fs/btrfs/inode.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2007 Oracle.  All rights reserved.
   4  */
   5
   6 #include <linux/kernel.h>
   7 #include <linux/bio.h>
   8 #include <linux/buffer_head.h>
   9 #include <linux/file.h>
  10 #include <linux/fs.h>
  11 #include <linux/pagemap.h>
  12 #include <linux/highmem.h>
  13 #include <linux/time.h>
  14 #include <linux/init.h>
  15 #include <linux/string.h>
  16 #include <linux/backing-dev.h>
  17 #include <linux/writeback.h>
  18 #include <linux/compat.h>
  19 #include <linux/xattr.h>
  20 #include <linux/posix_acl.h>
  21 #include <linux/falloc.h>
  22 #include <linux/slab.h>
  23 #include <linux/ratelimit.h>
  24 #include <linux/btrfs.h>
  25 #include <linux/blkdev.h>
  26 #include <linux/posix_acl_xattr.h>
  27 #include <linux/uio.h>
  28 #include <linux/magic.h>
  29 #include <linux/iversion.h>
  30 #include <linux/swap.h>
  31 #include <linux/sched/mm.h>
  32 #include <asm/unaligned.h>
  33 #include "misc.h"
  34 #include "ctree.h"
  35 #include "disk-io.h"
  36 #include "transaction.h"
  37 #include "btrfs_inode.h"
  38 #include "print-tree.h"
  39 #include "ordered-data.h"
  40 #include "xattr.h"
  41 #include "tree-log.h"
  42 #include "volumes.h"
  43 #include "compression.h"
  44 #include "locking.h"
  45 #include "free-space-cache.h"
  46 #include "inode-map.h"
  47 #include "props.h"
  48 #include "qgroup.h"
  49 #include "delalloc-space.h"
  50 #include "block-group.h"
  51
  52 struct btrfs_iget_args {
  53         struct btrfs_key *location;
  54         struct btrfs_root *root;
  55 };
  56
  57 struct btrfs_dio_data {
  58         u64 reserve;
  59         u64 unsubmitted_oe_range_start;
  60         u64 unsubmitted_oe_range_end;
  61         int overwrite;
  62 };
  63
  64 static const struct inode_operations btrfs_dir_inode_operations;
  65 static const struct inode_operations btrfs_symlink_inode_operations;
  66 static const struct inode_operations btrfs_special_inode_operations;
  67 static const struct inode_operations btrfs_file_inode_operations;
  68 static const struct address_space_operations btrfs_aops;
  69 static const struct file_operations btrfs_dir_file_operations;
  70 static const struct extent_io_ops btrfs_extent_io_ops;
  71
  72 static struct kmem_cache *btrfs_inode_cachep;
  73 struct kmem_cache *btrfs_trans_handle_cachep;
  74 struct kmem_cache *btrfs_path_cachep;
  75 struct kmem_cache *btrfs_free_space_cachep;
  76 struct kmem_cache *btrfs_free_space_bitmap_cachep;
  77
  78 static int btrfs_setsize(struct inode *inode, struct iattr *attr);
  79 static int btrfs_truncate(struct inode *inode, bool skip_writeback);
  80 static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent);
  81 static noinline int cow_file_range(struct inode *inode,
  82                                    struct page *locked_page,
  83                                    u64 start, u64 end, int *page_started,
  84                                    unsigned long *nr_written, int unlock);
  85 static struct extent_map *create_io_em(struct inode *inode, u64 start, u64 len,
  86                                        u64 orig_start, u64 block_start,
  87                                        u64 block_len, u64 orig_block_len,
  88                                        u64 ram_bytes, int compress_type,
  89                                        int type);
  90
  91 static void __endio_write_update_ordered(struct inode *inode,
  92                                          const u64 offset, const u64 bytes,
  93                                          const bool uptodate);
  94
  95 /*
  96  * Cleanup all submitted ordered extents in specified range to handle errors
  97  * from the btrfs_run_delalloc_range() callback.
  98  *
  99  * NOTE: caller must ensure that when an error happens, it can not call
 100  * extent_clear_unlock_delalloc() to clear both the bits EXTENT_DO_ACCOUNTING
 101  * and EXTENT_DELALLOC simultaneously, because that causes the reserved metadata
 102  * to be released, which we want to happen only when finishing the ordered
 103  * extent (btrfs_finish_ordered_io()).
 104  */
 105 static inline void btrfs_cleanup_ordered_extents(struct inode *inode,
 106                                                  struct page *locked_page,
 107                                                  u64 offset, u64 bytes)
 108 {
 109         unsigned long index = offset >> PAGE_SHIFT;
 110         unsigned long end_index = (offset + bytes - 1) >> PAGE_SHIFT;
 111         u64 page_start = page_offset(locked_page);
 112         u64 page_end = page_start + PAGE_SIZE - 1;
 113
 114         struct page *page;
 115
 116         while (index <= end_index) {
 117                 page = find_get_page(inode->i_mapping, index);
 118                 index++;
 119                 if (!page)
 120                         continue;
 121                 ClearPagePrivate2(page);
 122                 put_page(page);
 123         }
 124
 125         /*
 126          * In case this page belongs to the delalloc range being instantiated
 127          * then skip it, since the first page of a range is going to be
 128          * properly cleaned up by the caller of run_delalloc_range
 129          */
 130         if (page_start >= offset && page_end <= (offset + bytes - 1)) {
 131                 offset += PAGE_SIZE;
 132                 bytes -= PAGE_SIZE;
 133         }
 134
 135         return __endio_write_update_ordered(inode, offset, bytes, false);
 136 }
 137
 138 static int btrfs_dirty_inode(struct inode *inode);
 139
 140 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
 141 void btrfs_test_inode_set_ops(struct inode *inode)
 142 {
 143         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
 144 }
 145 #endif
 146
 147 static int btrfs_init_inode_security(struct btrfs_trans_handle *trans,
 148                                      struct inode *inode,  struct inode *dir,
 149                                      const struct qstr *qstr)
 150 {
 151         int err;
 152
 153         err = btrfs_init_acl(trans, inode, dir);
 154         if (!err)
 155                 err = btrfs_xattr_security_init(trans, inode, dir, qstr);
 156         return err;
 157 }
 158
 159 /*
 160  * this does all the hard work for inserting an inline extent into
 161  * the btree.  The caller should have done a btrfs_drop_extents so that
 162  * no overlapping inline items exist in the btree
 163  */
 164 static int insert_inline_extent(struct btrfs_trans_handle *trans,
 165                                 struct btrfs_path *path, int extent_inserted,
 166                                 struct btrfs_root *root, struct inode *inode,
 167                                 u64 start, size_t size, size_t compressed_size,
 168                                 int compress_type,
 169                                 struct page **compressed_pages)
 170 {
 171         struct extent_buffer *leaf;
 172         struct page *page = NULL;
 173         char *kaddr;
 174         unsigned long ptr;
 175         struct btrfs_file_extent_item *ei;
 176         int ret;
 177         size_t cur_size = size;
 178         unsigned long offset;
 179
 180         ASSERT((compressed_size > 0 && compressed_pages) ||
 181                (compressed_size == 0 && !compressed_pages));
 182
 183         if (compressed_size && compressed_pages)
 184                 cur_size = compressed_size;
 185
 186         inode_add_bytes(inode, size);
 187
 188         if (!extent_inserted) {
 189                 struct btrfs_key key;
 190                 size_t datasize;
 191
 192                 key.objectid = btrfs_ino(BTRFS_I(inode));
 193                 key.offset = start;
 194                 key.type = BTRFS_EXTENT_DATA_KEY;
 195
 196                 datasize = btrfs_file_extent_calc_inline_size(cur_size);
 197                 path->leave_spinning = 1;
 198                 ret = btrfs_insert_empty_item(trans, root, path, &key,
 199                                               datasize);
 200                 if (ret)
 201                         goto fail;
 202         }
 203         leaf = path->nodes[0];
 204         ei = btrfs_item_ptr(leaf, path->slots[0],
 205                             struct btrfs_file_extent_item);
 206         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
 207         btrfs_set_file_extent_type(leaf, ei, BTRFS_FILE_EXTENT_INLINE);
 208         btrfs_set_file_extent_encryption(leaf, ei, 0);
 209         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
 210         btrfs_set_file_extent_ram_bytes(leaf, ei, size);
 211         ptr = btrfs_file_extent_inline_start(ei);
 212
 213         if (compress_type != BTRFS_COMPRESS_NONE) {
 214                 struct page *cpage;
 215                 int i = 0;
 216                 while (compressed_size > 0) {
 217                         cpage = compressed_pages[i];
 218                         cur_size = min_t(unsigned long, compressed_size,
 219                                        PAGE_SIZE);
 220
 221                         kaddr = kmap_atomic(cpage);
 222                         write_extent_buffer(leaf, kaddr, ptr, cur_size);
 223                         kunmap_atomic(kaddr);
 224
 225                         i++;
 226                         ptr += cur_size;
 227                         compressed_size -= cur_size;
 228                 }
 229                 btrfs_set_file_extent_compression(leaf, ei,
 230                                                   compress_type);
 231         } else {
 232                 page = find_get_page(inode->i_mapping,
 233                                      start >> PAGE_SHIFT);
 234                 btrfs_set_file_extent_compression(leaf, ei, 0);
 235                 kaddr = kmap_atomic(page);
 236                 offset = offset_in_page(start);
 237                 write_extent_buffer(leaf, kaddr + offset, ptr, size);
 238                 kunmap_atomic(kaddr);
 239                 put_page(page);
 240         }
 241         btrfs_mark_buffer_dirty(leaf);
 242         btrfs_release_path(path);
 243
 244         /*
 245          * we're an inline extent, so nobody can
 246          * extend the file past i_size without locking
 247          * a page we already have locked.
 248          *
 249          * We must do any isize and inode updates
 250          * before we unlock the pages.  Otherwise we
 251          * could end up racing with unlink.
 252          */
 253         BTRFS_I(inode)->disk_i_size = inode->i_size;
 254         ret = btrfs_update_inode(trans, root, inode);
 255
 256 fail:
 257         return ret;
 258 }
 259
 260
 261 /*
 262  * conditionally insert an inline extent into the file.  This
 263  * does the checks required to make sure the data is small enough
 264  * to fit as an inline extent.
 265  */
 266 static noinline int cow_file_range_inline(struct inode *inode, u64 start,
 267                                           u64 end, size_t compressed_size,
 268                                           int compress_type,
 269                                           struct page **compressed_pages)
 270 {
 271         struct btrfs_root *root = BTRFS_I(inode)->root;
 272         struct btrfs_fs_info *fs_info = root->fs_info;
 273         struct btrfs_trans_handle *trans;
 274         u64 isize = i_size_read(inode);
 275         u64 actual_end = min(end + 1, isize);
 276         u64 inline_len = actual_end - start;
 277         u64 aligned_end = ALIGN(end, fs_info->sectorsize);
 278         u64 data_len = inline_len;
 279         int ret;
 280         struct btrfs_path *path;
 281         int extent_inserted = 0;
 282         u32 extent_item_size;
 283
 284         if (compressed_size)
 285                 data_len = compressed_size;
 286
 287         if (start > 0 ||
 288             actual_end > fs_info->sectorsize ||
 289             data_len > BTRFS_MAX_INLINE_DATA_SIZE(fs_info) ||
 290             (!compressed_size &&
 291             (actual_end & (fs_info->sectorsize - 1)) == 0) ||
 292             end + 1 < isize ||
 293             data_len > fs_info->max_inline) {
 294                 return 1;
 295         }
 296
 297         path = btrfs_alloc_path();
 298         if (!path)
 299                 return -ENOMEM;
 300
 301         trans = btrfs_join_transaction(root);
 302         if (IS_ERR(trans)) {
 303                 btrfs_free_path(path);
 304                 return PTR_ERR(trans);
 305         }
 306         trans->block_rsv = &BTRFS_I(inode)->block_rsv;
 307
 308         if (compressed_size && compressed_pages)
 309                 extent_item_size = btrfs_file_extent_calc_inline_size(
 310                    compressed_size);
 311         else
 312                 extent_item_size = btrfs_file_extent_calc_inline_size(
 313                     inline_len);
 314
 315         ret = __btrfs_drop_extents(trans, root, inode, path,
 316                                    start, aligned_end, NULL,
 317                                    1, 1, extent_item_size, &extent_inserted);
 318         if (ret) {
 319                 btrfs_abort_transaction(trans, ret);
 320                 goto out;
 321         }
 322
 323         if (isize > actual_end)
 324                 inline_len = min_t(u64, isize, actual_end);
 325         ret = insert_inline_extent(trans, path, extent_inserted,
 326                                    root, inode, start,
 327                                    inline_len, compressed_size,
 328                                    compress_type, compressed_pages);
 329         if (ret && ret != -ENOSPC) {
 330                 btrfs_abort_transaction(trans, ret);
 331                 goto out;
 332         } else if (ret == -ENOSPC) {
 333                 ret = 1;
 334                 goto out;
 335         }
 336
 337         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
 338         btrfs_drop_extent_cache(BTRFS_I(inode), start, aligned_end - 1, 0);
 339 out:
 340         /*
 341          * Don't forget to free the reserved space, as for inlined extent
 342          * it won't count as data extent, free them directly here.
 343          * And at reserve time, it's always aligned to page size, so
 344          * just free one page here.
 345          */
 346         btrfs_qgroup_free_data(inode, NULL, 0, PAGE_SIZE);
 347         btrfs_free_path(path);
 348         btrfs_end_transaction(trans);
 349         return ret;
 350 }
 351
 352 struct async_extent {
 353         u64 start;
 354         u64 ram_size;
 355         u64 compressed_size;
 356         struct page **pages;
 357         unsigned long nr_pages;
 358         int compress_type;
 359         struct list_head list;
 360 };
 361
 362 struct async_chunk {
 363         struct inode *inode;
 364         struct page *locked_page;
 365         u64 start;
 366         u64 end;
 367         unsigned int write_flags;
 368         struct list_head extents;
 369         struct cgroup_subsys_state *blkcg_css;
 370         struct btrfs_work work;
 371         atomic_t *pending;
 372 };
 373
 374 struct async_cow {
 375         /* Number of chunks in flight; must be first in the structure */
 376         atomic_t num_chunks;
 377         struct async_chunk chunks[];
 378 };
 379
 380 static noinline int add_async_extent(struct async_chunk *cow,
 381                                      u64 start, u64 ram_size,
 382                                      u64 compressed_size,
 383                                      struct page **pages,
 384                                      unsigned long nr_pages,
 385                                      int compress_type)
 386 {
 387         struct async_extent *async_extent;
 388
 389         async_extent = kmalloc(sizeof(*async_extent), GFP_NOFS);
 390         BUG_ON(!async_extent); /* -ENOMEM */
 391         async_extent->start = start;
 392         async_extent->ram_size = ram_size;
 393         async_extent->compressed_size = compressed_size;
 394         async_extent->pages = pages;
 395         async_extent->nr_pages = nr_pages;
 396         async_extent->compress_type = compress_type;
 397         list_add_tail(&async_extent->list, &cow->extents);
 398         return 0;
 399 }
 400
 401 /*
 402  * Check if the inode has flags compatible with compression
 403  */
 404 static inline bool inode_can_compress(struct inode *inode)
 405 {
 406         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW ||
 407             BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)
 408                 return false;
 409         return true;
 410 }
 411
 412 /*
 413  * Check if the inode needs to be submitted to compression, based on mount
 414  * options, defragmentation, properties or heuristics.
 415  */
 416 static inline int inode_need_compress(struct inode *inode, u64 start, u64 end)
 417 {
 418         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 419
 420         if (!inode_can_compress(inode)) {
 421                 WARN(IS_ENABLED(CONFIG_BTRFS_DEBUG),
 422                         KERN_ERR "BTRFS: unexpected compression for ino %llu\n",
 423                         btrfs_ino(BTRFS_I(inode)));
 424                 return 0;
 425         }
 426         /* force compress */
 427         if (btrfs_test_opt(fs_info, FORCE_COMPRESS))
 428                 return 1;
 429         /* defrag ioctl */
 430         if (BTRFS_I(inode)->defrag_compress)
 431                 return 1;
 432         /* bad compression ratios */
 433         if (BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS)
 434                 return 0;
 435         if (btrfs_test_opt(fs_info, COMPRESS) ||
 436             BTRFS_I(inode)->flags & BTRFS_INODE_COMPRESS ||
 437             BTRFS_I(inode)->prop_compress)
 438                 return btrfs_compress_heuristic(inode, start, end);
 439         return 0;
 440 }
 441
 442 static inline void inode_should_defrag(struct btrfs_inode *inode,
 443                 u64 start, u64 end, u64 num_bytes, u64 small_write)
 444 {
 445         /* If this is a small write inside eof, kick off a defrag */
 446         if (num_bytes < small_write &&
 447             (start > 0 || end + 1 < inode->disk_i_size))
 448                 btrfs_add_inode_defrag(NULL, inode);
 449 }
 450
 451 /*
 452  * we create compressed extents in two phases.  The first
 453  * phase compresses a range of pages that have already been
 454  * locked (both pages and state bits are locked).
 455  *
 456  * This is done inside an ordered work queue, and the compression
 457  * is spread across many cpus.  The actual IO submission is step
 458  * two, and the ordered work queue takes care of making sure that
 459  * happens in the same order things were put onto the queue by
 460  * writepages and friends.
 461  *
 462  * If this code finds it can't get good compression, it puts an
 463  * entry onto the work queue to write the uncompressed bytes.  This
 464  * makes sure that both compressed inodes and uncompressed inodes
 465  * are written in the same order that the flusher thread sent them
 466  * down.
 467  */
 468 static noinline int compress_file_range(struct async_chunk *async_chunk)
 469 {
 470         struct inode *inode = async_chunk->inode;
 471         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 472         u64 blocksize = fs_info->sectorsize;
 473         u64 start = async_chunk->start;
 474         u64 end = async_chunk->end;
 475         u64 actual_end;
 476         u64 i_size;
 477         int ret = 0;
 478         struct page **pages = NULL;
 479         unsigned long nr_pages;
 480         unsigned long total_compressed = 0;
 481         unsigned long total_in = 0;
 482         int i;
 483         int will_compress;
 484         int compress_type = fs_info->compress_type;
 485         int compressed_extents = 0;
 486         int redirty = 0;
 487
 488         inode_should_defrag(BTRFS_I(inode), start, end, end - start + 1,
 489                         SZ_16K);
 490
 491         /*
 492          * We need to save i_size before now because it could change in between
 493          * us evaluating the size and assigning it.  This is because we lock and
 494          * unlock the page in truncate and fallocate, and then modify the i_size
 495          * later on.
 496          *
 497          * The barriers are to emulate READ_ONCE, remove that once i_size_read
 498          * does that for us.
 499          */
 500         barrier();
 501         i_size = i_size_read(inode);
 502         barrier();
 503         actual_end = min_t(u64, i_size, end + 1);
 504 again:
 505         will_compress = 0;
 506         nr_pages = (end >> PAGE_SHIFT) - (start >> PAGE_SHIFT) + 1;
 507         BUILD_BUG_ON((BTRFS_MAX_COMPRESSED % PAGE_SIZE) != 0);
 508         nr_pages = min_t(unsigned long, nr_pages,
 509                         BTRFS_MAX_COMPRESSED / PAGE_SIZE);
 510
 511         /*
 512          * we don't want to send crud past the end of i_size through
 513          * compression, that's just a waste of CPU time.  So, if the
 514          * end of the file is before the start of our current
 515          * requested range of bytes, we bail out to the uncompressed
 516          * cleanup code that can deal with all of this.
 517          *
 518          * It isn't really the fastest way to fix things, but this is a
 519          * very uncommon corner.
 520          */
 521         if (actual_end <= start)
 522                 goto cleanup_and_bail_uncompressed;
 523
 524         total_compressed = actual_end - start;
 525
 526         /*
 527          * skip compression for a small file range(<=blocksize) that
 528          * isn't an inline extent, since it doesn't save disk space at all.
 529          */
 530         if (total_compressed <= blocksize &&
 531            (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
 532                 goto cleanup_and_bail_uncompressed;
 533
 534         total_compressed = min_t(unsigned long, total_compressed,
 535                         BTRFS_MAX_UNCOMPRESSED);
 536         total_in = 0;
 537         ret = 0;
 538
 539         /*
 540          * we do compression for mount -o compress and when the
 541          * inode has not been flagged as nocompress.  This flag can
 542          * change at any time if we discover bad compression ratios.
 543          */
 544         if (inode_need_compress(inode, start, end)) {
 545                 WARN_ON(pages);
 546                 pages = kcalloc(nr_pages, sizeof(struct page *), GFP_NOFS);
 547                 if (!pages) {
 548                         /* just bail out to the uncompressed code */
 549                         nr_pages = 0;
 550                         goto cont;
 551                 }
 552
 553                 if (BTRFS_I(inode)->defrag_compress)
 554                         compress_type = BTRFS_I(inode)->defrag_compress;
 555                 else if (BTRFS_I(inode)->prop_compress)
 556                         compress_type = BTRFS_I(inode)->prop_compress;
 557
 558                 /*
 559                  * we need to call clear_page_dirty_for_io on each
 560                  * page in the range.  Otherwise applications with the file
 561                  * mmap'd can wander in and change the page contents while
 562                  * we are compressing them.
 563                  *
 564                  * If the compression fails for any reason, we set the pages
 565                  * dirty again later on.
 566                  *
 567                  * Note that the remaining part is redirtied, the start pointer
 568                  * has moved, the end is the original one.
 569                  */
 570                 if (!redirty) {
 571                         extent_range_clear_dirty_for_io(inode, start, end);
 572                         redirty = 1;
 573                 }
 574
 575                 /* Compression level is applied here and only here */
 576                 ret = btrfs_compress_pages(
 577                         compress_type | (fs_info->compress_level << 4),
 578                                            inode->i_mapping, start,
 579                                            pages,
 580                                            &nr_pages,
 581                                            &total_in,
 582                                            &total_compressed);
 583
 584                 if (!ret) {
 585                         unsigned long offset = offset_in_page(total_compressed);
 586                         struct page *page = pages[nr_pages - 1];
 587                         char *kaddr;
 588
 589                         /* zero the tail end of the last page, we might be
 590                          * sending it down to disk
 591                          */
 592                         if (offset) {
 593                                 kaddr = kmap_atomic(page);
 594                                 memset(kaddr + offset, 0,
 595                                        PAGE_SIZE - offset);
 596                                 kunmap_atomic(kaddr);
 597                         }
 598                         will_compress = 1;
 599                 }
 600         }
 601 cont:
 602         if (start == 0) {
 603                 /* lets try to make an inline extent */
 604                 if (ret || total_in < actual_end) {
 605                         /* we didn't compress the entire range, try
 606                          * to make an uncompressed inline extent.
 607                          */
 608                         ret = cow_file_range_inline(inode, start, end, 0,
 609                                                     BTRFS_COMPRESS_NONE, NULL);
 610                 } else {
 611                         /* try making a compressed inline extent */
 612                         ret = cow_file_range_inline(inode, start, end,
 613                                                     total_compressed,
 614                                                     compress_type, pages);
 615                 }
 616                 if (ret <= 0) {
 617                         unsigned long clear_flags = EXTENT_DELALLOC |
 618                                 EXTENT_DELALLOC_NEW | EXTENT_DEFRAG |
 619                                 EXTENT_DO_ACCOUNTING;
 620                         unsigned long page_error_op;
 621
 622                         page_error_op = ret < 0 ? PAGE_SET_ERROR : 0;
 623
 624                         /*
 625                          * inline extent creation worked or returned error,
 626                          * we don't need to create any more async work items.
 627                          * Unlock and free up our temp pages.
 628                          *
 629                          * We use DO_ACCOUNTING here because we need the
 630                          * delalloc_release_metadata to be done _after_ we drop
 631                          * our outstanding extent for clearing delalloc for this
 632                          * range.
 633                          */
 634                         extent_clear_unlock_delalloc(inode, start, end, NULL,
 635                                                      clear_flags,
 636                                                      PAGE_UNLOCK |
 637                                                      PAGE_CLEAR_DIRTY |
 638                                                      PAGE_SET_WRITEBACK |
 639                                                      page_error_op |
 640                                                      PAGE_END_WRITEBACK);
 641
 642                         for (i = 0; i < nr_pages; i++) {
 643                                 WARN_ON(pages[i]->mapping);
 644                                 put_page(pages[i]);
 645                         }
 646                         kfree(pages);
 647
 648                         return 0;
 649                 }
 650         }
 651
 652         if (will_compress) {
 653                 /*
 654                  * we aren't doing an inline extent round the compressed size
 655                  * up to a block size boundary so the allocator does sane
 656                  * things
 657                  */
 658                 total_compressed = ALIGN(total_compressed, blocksize);
 659
 660                 /*
 661                  * one last check to make sure the compression is really a
 662                  * win, compare the page count read with the blocks on disk,
 663                  * compression must free at least one sector size
 664                  */
 665                 total_in = ALIGN(total_in, PAGE_SIZE);
 666                 if (total_compressed + blocksize <= total_in) {
 667                         compressed_extents++;
 668
 669                         /*
 670                          * The async work queues will take care of doing actual
 671                          * allocation on disk for these compressed pages, and
 672                          * will submit them to the elevator.
 673                          */
 674                         add_async_extent(async_chunk, start, total_in,
 675                                         total_compressed, pages, nr_pages,
 676                                         compress_type);
 677
 678                         if (start + total_in < end) {
 679                                 start += total_in;
 680                                 pages = NULL;
 681                                 cond_resched();
 682                                 goto again;
 683                         }
 684                         return compressed_extents;
 685                 }
 686         }
 687         if (pages) {
 688                 /*
 689                  * the compression code ran but failed to make things smaller,
 690                  * free any pages it allocated and our page pointer array
 691                  */
 692                 for (i = 0; i < nr_pages; i++) {
 693                         WARN_ON(pages[i]->mapping);
 694                         put_page(pages[i]);
 695                 }
 696                 kfree(pages);
 697                 pages = NULL;
 698                 total_compressed = 0;
 699                 nr_pages = 0;
 700
 701                 /* flag the file so we don't compress in the future */
 702                 if (!btrfs_test_opt(fs_info, FORCE_COMPRESS) &&
 703                     !(BTRFS_I(inode)->prop_compress)) {
 704                         BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
 705                 }
 706         }
 707 cleanup_and_bail_uncompressed:
 708         /*
 709          * No compression, but we still need to write the pages in the file
 710          * we've been given so far.  redirty the locked page if it corresponds
 711          * to our extent and set things up for the async work queue to run
 712          * cow_file_range to do the normal delalloc dance.
 713          */
 714         if (async_chunk->locked_page &&
 715             (page_offset(async_chunk->locked_page) >= start &&
 716              page_offset(async_chunk->locked_page)) <= end) {
 717                 __set_page_dirty_nobuffers(async_chunk->locked_page);
 718                 /* unlocked later on in the async handlers */
 719         }
 720
 721         if (redirty)
 722                 extent_range_redirty_for_io(inode, start, end);
 723         add_async_extent(async_chunk, start, end - start + 1, 0, NULL, 0,
 724                          BTRFS_COMPRESS_NONE);
 725         compressed_extents++;
 726
 727         return compressed_extents;
 728 }
 729
 730 static void free_async_extent_pages(struct async_extent *async_extent)
 731 {
 732         int i;
 733
 734         if (!async_extent->pages)
 735                 return;
 736
 737         for (i = 0; i < async_extent->nr_pages; i++) {
 738                 WARN_ON(async_extent->pages[i]->mapping);
 739                 put_page(async_extent->pages[i]);
 740         }
 741         kfree(async_extent->pages);
 742         async_extent->nr_pages = 0;
 743         async_extent->pages = NULL;
 744 }
 745
 746 /*
 747  * phase two of compressed writeback.  This is the ordered portion
 748  * of the code, which only gets called in the order the work was
 749  * queued.  We walk all the async extents created by compress_file_range
 750  * and send them down to the disk.
 751  */
 752 static noinline void submit_compressed_extents(struct async_chunk *async_chunk)
 753 {
 754         struct inode *inode = async_chunk->inode;
 755         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 756         struct async_extent *async_extent;
 757         u64 alloc_hint = 0;
 758         struct btrfs_key ins;
 759         struct extent_map *em;
 760         struct btrfs_root *root = BTRFS_I(inode)->root;
 761         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
 762         int ret = 0;
 763
 764 again:
 765         while (!list_empty(&async_chunk->extents)) {
 766                 async_extent = list_entry(async_chunk->extents.next,
 767                                           struct async_extent, list);
 768                 list_del(&async_extent->list);
 769
 770 retry:
 771                 lock_extent(io_tree, async_extent->start,
 772                             async_extent->start + async_extent->ram_size - 1);
 773                 /* did the compression code fall back to uncompressed IO? */
 774                 if (!async_extent->pages) {
 775                         int page_started = 0;
 776                         unsigned long nr_written = 0;
 777
 778                         /* allocate blocks */
 779                         ret = cow_file_range(inode, async_chunk->locked_page,
 780                                              async_extent->start,
 781                                              async_extent->start +
 782                                              async_extent->ram_size - 1,
 783                                              &page_started, &nr_written, 0);
 784
 785                         /* JDM XXX */
 786
 787                         /*
 788                          * if page_started, cow_file_range inserted an
 789                          * inline extent and took care of all the unlocking
 790                          * and IO for us.  Otherwise, we need to submit
 791                          * all those pages down to the drive.
 792                          */
 793                         if (!page_started && !ret)
 794                                 extent_write_locked_range(inode,
 795                                                   async_extent->start,
 796                                                   async_extent->start +
 797                                                   async_extent->ram_size - 1,
 798                                                   WB_SYNC_ALL);
 799                         else if (ret && async_chunk->locked_page)
 800                                 unlock_page(async_chunk->locked_page);
 801                         kfree(async_extent);
 802                         cond_resched();
 803                         continue;
 804                 }
 805
 806                 ret = btrfs_reserve_extent(root, async_extent->ram_size,
 807                                            async_extent->compressed_size,
 808                                            async_extent->compressed_size,
 809                                            0, alloc_hint, &ins, 1, 1);
 810                 if (ret) {
 811                         free_async_extent_pages(async_extent);
 812
 813                         if (ret == -ENOSPC) {
 814                                 unlock_extent(io_tree, async_extent->start,
 815                                               async_extent->start +
 816                                               async_extent->ram_size - 1);
 817
 818                                 /*
 819                                  * we need to redirty the pages if we decide to
 820                                  * fallback to uncompressed IO, otherwise we
 821                                  * will not submit these pages down to lower
 822                                  * layers.
 823                                  */
 824                                 extent_range_redirty_for_io(inode,
 825                                                 async_extent->start,
 826                                                 async_extent->start +
 827                                                 async_extent->ram_size - 1);
 828
 829                                 goto retry;
 830                         }
 831                         goto out_free;
 832                 }
 833                 /*
 834                  * here we're doing allocation and writeback of the
 835                  * compressed pages
 836                  */
 837                 em = create_io_em(inode, async_extent->start,
 838                                   async_extent->ram_size, /* len */
 839                                   async_extent->start, /* orig_start */
 840                                   ins.objectid, /* block_start */
 841                                   ins.offset, /* block_len */
 842                                   ins.offset, /* orig_block_len */
 843                                   async_extent->ram_size, /* ram_bytes */
 844                                   async_extent->compress_type,
 845                                   BTRFS_ORDERED_COMPRESSED);
 846                 if (IS_ERR(em))
 847                         /* ret value is not necessary due to void function */
 848                         goto out_free_reserve;
 849                 free_extent_map(em);
 850
 851                 ret = btrfs_add_ordered_extent_compress(inode,
 852                                                 async_extent->start,
 853                                                 ins.objectid,
 854                                                 async_extent->ram_size,
 855                                                 ins.offset,
 856                                                 BTRFS_ORDERED_COMPRESSED,
 857                                                 async_extent->compress_type);
 858                 if (ret) {
 859                         btrfs_drop_extent_cache(BTRFS_I(inode),
 860                                                 async_extent->start,
 861                                                 async_extent->start +
 862                                                 async_extent->ram_size - 1, 0);
 863                         goto out_free_reserve;
 864                 }
 865                 btrfs_dec_block_group_reservations(fs_info, ins.objectid);
 866
 867                 /*
 868                  * clear dirty, set writeback and unlock the pages.
 869                  */
 870                 extent_clear_unlock_delalloc(inode, async_extent->start,
 871                                 async_extent->start +
 872                                 async_extent->ram_size - 1,
 873                                 NULL, EXTENT_LOCKED | EXTENT_DELALLOC,
 874                                 PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
 875                                 PAGE_SET_WRITEBACK);
 876                 if (btrfs_submit_compressed_write(inode,
 877                                     async_extent->start,
 878                                     async_extent->ram_size,
 879                                     ins.objectid,
 880                                     ins.offset, async_extent->pages,
 881                                     async_extent->nr_pages,
 882                                     async_chunk->write_flags,
 883                                     async_chunk->blkcg_css)) {
 884                         struct page *p = async_extent->pages[0];
 885                         const u64 start = async_extent->start;
 886                         const u64 end = start + async_extent->ram_size - 1;
 887
 888                         p->mapping = inode->i_mapping;
 889                         btrfs_writepage_endio_finish_ordered(p, start, end, 0);
 890
 891                         p->mapping = NULL;
 892                         extent_clear_unlock_delalloc(inode, start, end,
 893                                                      NULL, 0,
 894                                                      PAGE_END_WRITEBACK |
 895                                                      PAGE_SET_ERROR);
 896                         free_async_extent_pages(async_extent);
 897                 }
 898                 alloc_hint = ins.objectid + ins.offset;
 899                 kfree(async_extent);
 900                 cond_resched();
 901         }
 902         return;
 903 out_free_reserve:
 904         btrfs_dec_block_group_reservations(fs_info, ins.objectid);
 905         btrfs_free_reserved_extent(fs_info, ins.objectid, ins.offset, 1);
 906 out_free:
 907         extent_clear_unlock_delalloc(inode, async_extent->start,
 908                                      async_extent->start +
 909                                      async_extent->ram_size - 1,
 910                                      NULL, EXTENT_LOCKED | EXTENT_DELALLOC |
 911                                      EXTENT_DELALLOC_NEW |
 912                                      EXTENT_DEFRAG | EXTENT_DO_ACCOUNTING,
 913                                      PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
 914                                      PAGE_SET_WRITEBACK | PAGE_END_WRITEBACK |
 915                                      PAGE_SET_ERROR);
 916         free_async_extent_pages(async_extent);
 917         kfree(async_extent);
 918         goto again;
 919 }
 920
 921 static u64 get_extent_allocation_hint(struct inode *inode, u64 start,
 922                                       u64 num_bytes)
 923 {
 924         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 925         struct extent_map *em;
 926         u64 alloc_hint = 0;
 927
 928         read_lock(&em_tree->lock);
 929         em = search_extent_mapping(em_tree, start, num_bytes);
 930         if (em) {
 931                 /*
 932                  * if block start isn't an actual block number then find the
 933                  * first block in this inode and use that as a hint.  If that
 934                  * block is also bogus then just don't worry about it.
 935                  */
 936                 if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
 937                         free_extent_map(em);
 938                         em = search_extent_mapping(em_tree, 0, 0);
 939                         if (em && em->block_start < EXTENT_MAP_LAST_BYTE)
 940                                 alloc_hint = em->block_start;
 941                         if (em)
 942                                 free_extent_map(em);
 943                 } else {
 944                         alloc_hint = em->block_start;
 945                         free_extent_map(em);
 946                 }
 947         }
 948         read_unlock(&em_tree->lock);
 949
 950         return alloc_hint;
 951 }
 952
 953 /*
 954  * when extent_io.c finds a delayed allocation range in the file,
 955  * the call backs end up in this code.  The basic idea is to
 956  * allocate extents on disk for the range, and create ordered data structs
 957  * in ram to track those extents.
 958  *
 959  * locked_page is the page that writepage had locked already.  We use
 960  * it to make sure we don't do extra locks or unlocks.
 961  *
 962  * *page_started is set to one if we unlock locked_page and do everything
 963  * required to start IO on it.  It may be clean and already done with
 964  * IO when we return.
 965  */
 966 static noinline int cow_file_range(struct inode *inode,
 967                                    struct page *locked_page,
 968                                    u64 start, u64 end, int *page_started,
 969                                    unsigned long *nr_written, int unlock)
 970 {
 971         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 972         struct btrfs_root *root = BTRFS_I(inode)->root;
 973         u64 alloc_hint = 0;
 974         u64 num_bytes;
 975         unsigned long ram_size;
 976         u64 cur_alloc_size = 0;
 977         u64 blocksize = fs_info->sectorsize;
 978         struct btrfs_key ins;
 979         struct extent_map *em;
 980         unsigned clear_bits;
 981         unsigned long page_ops;
 982         bool extent_reserved = false;
 983         int ret = 0;
 984
 985         if (btrfs_is_free_space_inode(BTRFS_I(inode))) {
 986                 WARN_ON_ONCE(1);
 987                 ret = -EINVAL;
 988                 goto out_unlock;
 989         }
 990
 991         num_bytes = ALIGN(end - start + 1, blocksize);
 992         num_bytes = max(blocksize,  num_bytes);
 993         ASSERT(num_bytes <= btrfs_super_total_bytes(fs_info->super_copy));
 994
 995         inode_should_defrag(BTRFS_I(inode), start, end, num_bytes, SZ_64K);
 996
 997         if (start == 0) {
 998                 /* lets try to make an inline extent */
 999                 ret = cow_file_range_inline(inode, start, end, 0,
1000                                             BTRFS_COMPRESS_NONE, NULL);
1001                 if (ret == 0) {
1002                         /*
1003                          * We use DO_ACCOUNTING here because we need the
1004                          * delalloc_release_metadata to be run _after_ we drop
1005                          * our outstanding extent for clearing delalloc for this
1006                          * range.
1007                          */
1008                         extent_clear_unlock_delalloc(inode, start, end, NULL,
1009                                      EXTENT_LOCKED | EXTENT_DELALLOC |
1010                                      EXTENT_DELALLOC_NEW | EXTENT_DEFRAG |
1011                                      EXTENT_DO_ACCOUNTING, PAGE_UNLOCK |
1012                                      PAGE_CLEAR_DIRTY | PAGE_SET_WRITEBACK |
1013                                      PAGE_END_WRITEBACK);
1014                         *nr_written = *nr_written +
1015                              (end - start + PAGE_SIZE) / PAGE_SIZE;
1016                         *page_started = 1;
1017                         goto out;
1018                 } else if (ret < 0) {
1019                         goto out_unlock;
1020                 }
1021         }
1022
1023         alloc_hint = get_extent_allocation_hint(inode, start, num_bytes);
1024         btrfs_drop_extent_cache(BTRFS_I(inode), start,
1025                         start + num_bytes - 1, 0);
1026
1027         while (num_bytes > 0) {
1028                 cur_alloc_size = num_bytes;
1029                 ret = btrfs_reserve_extent(root, cur_alloc_size, cur_alloc_size,
1030                                            fs_info->sectorsize, 0, alloc_hint,
1031                                            &ins, 1, 1);
1032                 if (ret < 0)
1033                         goto out_unlock;
1034                 cur_alloc_size = ins.offset;
1035                 extent_reserved = true;
1036
1037                 ram_size = ins.offset;
1038                 em = create_io_em(inode, start, ins.offset, /* len */
1039                                   start, /* orig_start */
1040                                   ins.objectid, /* block_start */
1041                                   ins.offset, /* block_len */
1042                                   ins.offset, /* orig_block_len */
1043                                   ram_size, /* ram_bytes */
1044                                   BTRFS_COMPRESS_NONE, /* compress_type */
1045                                   BTRFS_ORDERED_REGULAR /* type */);
1046                 if (IS_ERR(em)) {
1047                         ret = PTR_ERR(em);
1048                         goto out_reserve;
1049                 }
1050                 free_extent_map(em);
1051
1052                 ret = btrfs_add_ordered_extent(inode, start, ins.objectid,
1053                                                ram_size, cur_alloc_size, 0);
1054                 if (ret)
1055                         goto out_drop_extent_cache;
1056
1057                 if (root->root_key.objectid ==
1058                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
1059                         ret = btrfs_reloc_clone_csums(inode, start,
1060                                                       cur_alloc_size);
1061                         /*
1062                          * Only drop cache here, and process as normal.
1063                          *
1064                          * We must not allow extent_clear_unlock_delalloc()
1065                          * at out_unlock label to free meta of this ordered
1066                          * extent, as its meta should be freed by
1067                          * btrfs_finish_ordered_io().
1068                          *
1069                          * So we must continue until @start is increased to
1070                          * skip current ordered extent.
1071                          */
1072                         if (ret)
1073                                 btrfs_drop_extent_cache(BTRFS_I(inode), start,
1074                                                 start + ram_size - 1, 0);
1075                 }
1076
1077                 btrfs_dec_block_group_reservations(fs_info, ins.objectid);
1078
1079                 /* we're not doing compressed IO, don't unlock the first
1080                  * page (which the caller expects to stay locked), don't
1081                  * clear any dirty bits and don't set any writeback bits
1082                  *
1083                  * Do set the Private2 bit so we know this page was properly
1084                  * setup for writepage
1085                  */
1086                 page_ops = unlock ? PAGE_UNLOCK : 0;
1087                 page_ops |= PAGE_SET_PRIVATE2;
1088
1089                 extent_clear_unlock_delalloc(inode, start,
1090                                              start + ram_size - 1,
1091                                              locked_page,
1092                                              EXTENT_LOCKED | EXTENT_DELALLOC,
1093                                              page_ops);
1094                 if (num_bytes < cur_alloc_size)
1095                         num_bytes = 0;
1096                 else
1097                         num_bytes -= cur_alloc_size;
1098                 alloc_hint = ins.objectid + ins.offset;
1099                 start += cur_alloc_size;
1100                 extent_reserved = false;
1101
1102                 /*
1103                  * btrfs_reloc_clone_csums() error, since start is increased
1104                  * extent_clear_unlock_delalloc() at out_unlock label won't
1105                  * free metadata of current ordered extent, we're OK to exit.
1106                  */
1107                 if (ret)
1108                         goto out_unlock;
1109         }
1110 out:
1111         return ret;
1112
1113 out_drop_extent_cache:
1114         btrfs_drop_extent_cache(BTRFS_I(inode), start, start + ram_size - 1, 0);
1115 out_reserve:
1116         btrfs_dec_block_group_reservations(fs_info, ins.objectid);
1117         btrfs_free_reserved_extent(fs_info, ins.objectid, ins.offset, 1);
1118 out_unlock:
1119         clear_bits = EXTENT_LOCKED | EXTENT_DELALLOC | EXTENT_DELALLOC_NEW |
1120                 EXTENT_DEFRAG | EXTENT_CLEAR_META_RESV;
1121         page_ops = PAGE_UNLOCK | PAGE_CLEAR_DIRTY | PAGE_SET_WRITEBACK |
1122                 PAGE_END_WRITEBACK;
1123         /*
1124          * If we reserved an extent for our delalloc range (or a subrange) and
1125          * failed to create the respective ordered extent, then it means that
1126          * when we reserved the extent we decremented the extent's size from
1127          * the data space_info's bytes_may_use counter and incremented the
1128          * space_info's bytes_reserved counter by the same amount. We must make
1129          * sure extent_clear_unlock_delalloc() does not try to decrement again
1130          * the data space_info's bytes_may_use counter, therefore we do not pass
1131          * it the flag EXTENT_CLEAR_DATA_RESV.
1132          */
1133         if (extent_reserved) {
1134                 extent_clear_unlock_delalloc(inode, start,
1135                                              start + cur_alloc_size,
1136                                              locked_page,
1137                                              clear_bits,
1138                                              page_ops);
1139                 start += cur_alloc_size;
1140                 if (start >= end)
1141                         goto out;
1142         }
1143         extent_clear_unlock_delalloc(inode, start, end, locked_page,
1144                                      clear_bits | EXTENT_CLEAR_DATA_RESV,
1145                                      page_ops);
1146         goto out;
1147 }
1148
1149 /*
1150  * work queue call back to started compression on a file and pages
1151  */
1152 static noinline void async_cow_start(struct btrfs_work *work)
1153 {
1154         struct async_chunk *async_chunk;
1155         int compressed_extents;
1156
1157         async_chunk = container_of(work, struct async_chunk, work);
1158
1159         compressed_extents = compress_file_range(async_chunk);
1160         if (compressed_extents == 0) {
1161                 btrfs_add_delayed_iput(async_chunk->inode);
1162                 async_chunk->inode = NULL;
1163         }
1164 }
1165
1166 /*
1167  * work queue call back to submit previously compressed pages
1168  */
1169 static noinline void async_cow_submit(struct btrfs_work *work)
1170 {
1171         struct async_chunk *async_chunk = container_of(work, struct async_chunk,
1172                                                      work);
1173         struct btrfs_fs_info *fs_info = btrfs_work_owner(work);
1174         unsigned long nr_pages;
1175
1176         nr_pages = (async_chunk->end - async_chunk->start + PAGE_SIZE) >>
1177                 PAGE_SHIFT;
1178
1179         /* atomic_sub_return implies a barrier */
1180         if (atomic_sub_return(nr_pages, &fs_info->async_delalloc_pages) <
1181             5 * SZ_1M)
1182                 cond_wake_up_nomb(&fs_info->async_submit_wait);
1183
1184         /*
1185          * ->inode could be NULL if async_chunk_start has failed to compress,
1186          * in which case we don't have anything to submit, yet we need to
1187          * always adjust ->async_delalloc_pages as its paired with the init
1188          * happening in cow_file_range_async
1189          */
1190         if (async_chunk->inode)
1191                 submit_compressed_extents(async_chunk);
1192 }
1193
1194 static noinline void async_cow_free(struct btrfs_work *work)
1195 {
1196         struct async_chunk *async_chunk;
1197
1198         async_chunk = container_of(work, struct async_chunk, work);
1199         if (async_chunk->inode)
1200                 btrfs_add_delayed_iput(async_chunk->inode);
1201         if (async_chunk->blkcg_css)
1202                 css_put(async_chunk->blkcg_css);
1203         /*
1204          * Since the pointer to 'pending' is at the beginning of the array of
1205          * async_chunk's, freeing it ensures the whole array has been freed.
1206          */
1207         if (atomic_dec_and_test(async_chunk->pending))
1208                 kvfree(async_chunk->pending);
1209 }
1210
1211 static int cow_file_range_async(struct inode *inode,
1212                                 struct writeback_control *wbc,
1213                                 struct page *locked_page,
1214                                 u64 start, u64 end, int *page_started,
1215                                 unsigned long *nr_written)
1216 {
1217         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1218         struct cgroup_subsys_state *blkcg_css = wbc_blkcg_css(wbc);
1219         struct async_cow *ctx;
1220         struct async_chunk *async_chunk;
1221         unsigned long nr_pages;
1222         u64 cur_end;
1223         u64 num_chunks = DIV_ROUND_UP(end - start, SZ_512K);
1224         int i;
1225         bool should_compress;
1226         unsigned nofs_flag;
1227         const unsigned int write_flags = wbc_to_write_flags(wbc);
1228
1229         unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
1230
1231         if (BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS &&
1232             !btrfs_test_opt(fs_info, FORCE_COMPRESS)) {
1233                 num_chunks = 1;
1234                 should_compress = false;
1235         } else {
1236                 should_compress = true;
1237         }
1238
1239         nofs_flag = memalloc_nofs_save();
1240         ctx = kvmalloc(struct_size(ctx, chunks, num_chunks), GFP_KERNEL);
1241         memalloc_nofs_restore(nofs_flag);
1242
1243         if (!ctx) {
1244                 unsigned clear_bits = EXTENT_LOCKED | EXTENT_DELALLOC |
1245                         EXTENT_DELALLOC_NEW | EXTENT_DEFRAG |
1246                         EXTENT_DO_ACCOUNTING;
1247                 unsigned long page_ops = PAGE_UNLOCK | PAGE_CLEAR_DIRTY |
1248                         PAGE_SET_WRITEBACK | PAGE_END_WRITEBACK |
1249                         PAGE_SET_ERROR;
1250
1251                 extent_clear_unlock_delalloc(inode, start, end, locked_page,
1252                                              clear_bits, page_ops);
1253                 return -ENOMEM;
1254         }
1255
1256         async_chunk = ctx->chunks;
1257         atomic_set(&ctx->num_chunks, num_chunks);
1258
1259         for (i = 0; i < num_chunks; i++) {
1260                 if (should_compress)
1261                         cur_end = min(end, start + SZ_512K - 1);
1262                 else
1263                         cur_end = end;
1264
1265                 /*
1266                  * igrab is called higher up in the call chain, take only the
1267                  * lightweight reference for the callback lifetime
1268                  */
1269                 ihold(inode);
1270                 async_chunk[i].pending = &ctx->num_chunks;
1271                 async_chunk[i].inode = inode;
1272                 async_chunk[i].start = start;
1273                 async_chunk[i].end = cur_end;
1274                 async_chunk[i].write_flags = write_flags;
1275                 INIT_LIST_HEAD(&async_chunk[i].extents);
1276
1277                 /*
1278                  * The locked_page comes all the way from writepage and its
1279                  * the original page we were actually given.  As we spread
1280                  * this large delalloc region across multiple async_chunk
1281                  * structs, only the first struct needs a pointer to locked_page
1282                  *
1283                  * This way we don't need racey decisions about who is supposed
1284                  * to unlock it.
1285                  */
1286                 if (locked_page) {
1287                         /*
1288                          * Depending on the compressibility, the pages might or
1289                          * might not go through async.  We want all of them to
1290                          * be accounted against wbc once.  Let's do it here
1291                          * before the paths diverge.  wbc accounting is used
1292                          * only for foreign writeback detection and doesn't
1293                          * need full accuracy.  Just account the whole thing
1294                          * against the first page.
1295                          */
1296                         wbc_account_cgroup_owner(wbc, locked_page,
1297                                                  cur_end - start);
1298                         async_chunk[i].locked_page = locked_page;
1299                         locked_page = NULL;
1300                 } else {
1301                         async_chunk[i].locked_page = NULL;
1302                 }
1303
1304                 if (blkcg_css != blkcg_root_css) {
1305                         css_get(blkcg_css);
1306                         async_chunk[i].blkcg_css = blkcg_css;
1307                 } else {
1308                         async_chunk[i].blkcg_css = NULL;
1309                 }
1310
1311                 btrfs_init_work(&async_chunk[i].work, async_cow_start,
1312                                 async_cow_submit, async_cow_free);
1313
1314                 nr_pages = DIV_ROUND_UP(cur_end - start, PAGE_SIZE);
1315                 atomic_add(nr_pages, &fs_info->async_delalloc_pages);
1316
1317                 btrfs_queue_work(fs_info->delalloc_workers, &async_chunk[i].work);
1318
1319                 *nr_written += nr_pages;
1320                 start = cur_end + 1;
1321         }
1322         *page_started = 1;
1323         return 0;
1324 }
1325
1326 static noinline int csum_exist_in_range(struct btrfs_fs_info *fs_info,
1327                                         u64 bytenr, u64 num_bytes)
1328 {
1329         int ret;
1330         struct btrfs_ordered_sum *sums;
1331         LIST_HEAD(list);
1332
1333         ret = btrfs_lookup_csums_range(fs_info->csum_root, bytenr,
1334                                        bytenr + num_bytes - 1, &list, 0);
1335         if (ret == 0 && list_empty(&list))
1336                 return 0;
1337
1338         while (!list_empty(&list)) {
1339                 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
1340                 list_del(&sums->list);
1341                 kfree(sums);
1342         }
1343         if (ret < 0)
1344                 return ret;
1345         return 1;
1346 }
1347
1348 /*
1349  * when nowcow writeback call back.  This checks for snapshots or COW copies
1350  * of the extents that exist in the file, and COWs the file as required.
1351  *
1352  * If no cow copies or snapshots exist, we write directly to the existing
1353  * blocks on disk
1354  */
1355 static noinline int run_delalloc_nocow(struct inode *inode,
1356                                        struct page *locked_page,
1357                                        const u64 start, const u64 end,
1358                                        int *page_started, int force,
1359                                        unsigned long *nr_written)
1360 {
1361         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1362         struct btrfs_root *root = BTRFS_I(inode)->root;
1363         struct btrfs_path *path;
1364         u64 cow_start = (u64)-1;
1365         u64 cur_offset = start;
1366         int ret;
1367         bool check_prev = true;
1368         const bool freespace_inode = btrfs_is_free_space_inode(BTRFS_I(inode));
1369         u64 ino = btrfs_ino(BTRFS_I(inode));
1370         bool nocow = false;
1371         u64 disk_bytenr = 0;
1372
1373         path = btrfs_alloc_path();
1374         if (!path) {
1375                 extent_clear_unlock_delalloc(inode, start, end, locked_page,
1376                                              EXTENT_LOCKED | EXTENT_DELALLOC |
1377                                              EXTENT_DO_ACCOUNTING |
1378                                              EXTENT_DEFRAG, PAGE_UNLOCK |
1379                                              PAGE_CLEAR_DIRTY |
1380                                              PAGE_SET_WRITEBACK |
1381                                              PAGE_END_WRITEBACK);
1382                 return -ENOMEM;
1383         }
1384
1385         while (1) {
1386                 struct btrfs_key found_key;
1387                 struct btrfs_file_extent_item *fi;
1388                 struct extent_buffer *leaf;
1389                 u64 extent_end;
1390                 u64 extent_offset;
1391                 u64 num_bytes = 0;
1392                 u64 disk_num_bytes;
1393                 u64 ram_bytes;
1394                 int extent_type;
1395
1396                 nocow = false;
1397
1398                 ret = btrfs_lookup_file_extent(NULL, root, path, ino,
1399                                                cur_offset, 0);
1400                 if (ret < 0)
1401                         goto error;
1402
1403                 /*
1404                  * If there is no extent for our range when doing the initial
1405                  * search, then go back to the previous slot as it will be the
1406                  * one containing the search offset
1407                  */
1408                 if (ret > 0 && path->slots[0] > 0 && check_prev) {
1409                         leaf = path->nodes[0];
1410                         btrfs_item_key_to_cpu(leaf, &found_key,
1411                                               path->slots[0] - 1);
1412                         if (found_key.objectid == ino &&
1413                             found_key.type == BTRFS_EXTENT_DATA_KEY)
1414                                 path->slots[0]--;
1415                 }
1416                 check_prev = false;
1417 next_slot:
1418                 /* Go to next leaf if we have exhausted the current one */
1419                 leaf = path->nodes[0];
1420                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1421                         ret = btrfs_next_leaf(root, path);
1422                         if (ret < 0) {
1423                                 if (cow_start != (u64)-1)
1424                                         cur_offset = cow_start;
1425                                 goto error;
1426                         }
1427                         if (ret > 0)
1428                                 break;
1429                         leaf = path->nodes[0];
1430                 }
1431
1432                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1433
1434                 /* Didn't find anything for our INO */
1435                 if (found_key.objectid > ino)
1436                         break;
1437                 /*
1438                  * Keep searching until we find an EXTENT_ITEM or there are no
1439                  * more extents for this inode
1440                  */
1441                 if (WARN_ON_ONCE(found_key.objectid < ino) ||
1442                     found_key.type < BTRFS_EXTENT_DATA_KEY) {
1443                         path->slots[0]++;
1444                         goto next_slot;
1445                 }
1446
1447                 /* Found key is not EXTENT_DATA_KEY or starts after req range */
1448                 if (found_key.type > BTRFS_EXTENT_DATA_KEY ||
1449                     found_key.offset > end)
1450                         break;
1451
1452                 /*
1453                  * If the found extent starts after requested offset, then
1454                  * adjust extent_end to be right before this extent begins
1455                  */
1456                 if (found_key.offset > cur_offset) {
1457                         extent_end = found_key.offset;
1458                         extent_type = 0;
1459                         goto out_check;
1460                 }
1461
1462                 /*
1463                  * Found extent which begins before our range and potentially
1464                  * intersect it
1465                  */
1466                 fi = btrfs_item_ptr(leaf, path->slots[0],
1467                                     struct btrfs_file_extent_item);
1468                 extent_type = btrfs_file_extent_type(leaf, fi);
1469
1470                 ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
1471                 if (extent_type == BTRFS_FILE_EXTENT_REG ||
1472                     extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1473                         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1474                         extent_offset = btrfs_file_extent_offset(leaf, fi);
1475                         extent_end = found_key.offset +
1476                                 btrfs_file_extent_num_bytes(leaf, fi);
1477                         disk_num_bytes =
1478                                 btrfs_file_extent_disk_num_bytes(leaf, fi);
1479                         /*
1480                          * If the extent we got ends before our current offset,
1481                          * skip to the next extent.
1482                          */
1483                         if (extent_end <= cur_offset) {
1484                                 path->slots[0]++;
1485                                 goto next_slot;
1486                         }
1487                         /* Skip holes */
1488                         if (disk_bytenr == 0)
1489                                 goto out_check;
1490                         /* Skip compressed/encrypted/encoded extents */
1491                         if (btrfs_file_extent_compression(leaf, fi) ||
1492                             btrfs_file_extent_encryption(leaf, fi) ||
1493                             btrfs_file_extent_other_encoding(leaf, fi))
1494                                 goto out_check;
1495                         /*
1496                          * If extent is created before the last volume's snapshot
1497                          * this implies the extent is shared, hence we can't do
1498                          * nocow. This is the same check as in
1499                          * btrfs_cross_ref_exist but without calling
1500                          * btrfs_search_slot.
1501                          */
1502                         if (!freespace_inode &&
1503                             btrfs_file_extent_generation(leaf, fi) <=
1504                             btrfs_root_last_snapshot(&root->root_item))
1505                                 goto out_check;
1506                         if (extent_type == BTRFS_FILE_EXTENT_REG && !force)
1507                                 goto out_check;
1508                         /* If extent is RO, we must COW it */
1509                         if (btrfs_extent_readonly(fs_info, disk_bytenr))
1510                                 goto out_check;
1511                         ret = btrfs_cross_ref_exist(root, ino,
1512                                                     found_key.offset -
1513                                                     extent_offset, disk_bytenr);
1514                         if (ret) {
1515                                 /*
1516                                  * ret could be -EIO if the above fails to read
1517                                  * metadata.
1518                                  */
1519                                 if (ret < 0) {
1520                                         if (cow_start != (u64)-1)
1521                                                 cur_offset = cow_start;
1522                                         goto error;
1523                                 }
1524
1525                                 WARN_ON_ONCE(freespace_inode);
1526                                 goto out_check;
1527                         }
1528                         disk_bytenr += extent_offset;
1529                         disk_bytenr += cur_offset - found_key.offset;
1530                         num_bytes = min(end + 1, extent_end) - cur_offset;
1531                         /*
1532                          * If there are pending snapshots for this root, we
1533                          * fall into common COW way
1534                          */
1535                         if (!freespace_inode && atomic_read(&root->snapshot_force_cow))
1536                                 goto out_check;
1537                         /*
1538                          * force cow if csum exists in the range.
1539                          * this ensure that csum for a given extent are
1540                          * either valid or do not exist.
1541                          */
1542                         ret = csum_exist_in_range(fs_info, disk_bytenr,
1543                                                   num_bytes);
1544                         if (ret) {
1545                                 /*
1546                                  * ret could be -EIO if the above fails to read
1547                                  * metadata.
1548                                  */
1549                                 if (ret < 0) {
1550                                         if (cow_start != (u64)-1)
1551                                                 cur_offset = cow_start;
1552                                         goto error;
1553                                 }
1554                                 WARN_ON_ONCE(freespace_inode);
1555                                 goto out_check;
1556                         }
1557                         if (!btrfs_inc_nocow_writers(fs_info, disk_bytenr))
1558                                 goto out_check;
1559                         nocow = true;
1560                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
1561                         extent_end = found_key.offset + ram_bytes;
1562                         extent_end = ALIGN(extent_end, fs_info->sectorsize);
1563                         /* Skip extents outside of our requested range */
1564                         if (extent_end <= start) {
1565                                 path->slots[0]++;
1566                                 goto next_slot;
1567                         }
1568                 } else {
1569                         /* If this triggers then we have a memory corruption */
1570                         BUG();
1571                 }
1572 out_check:
1573                 /*
1574                  * If nocow is false then record the beginning of the range
1575                  * that needs to be COWed
1576                  */
1577                 if (!nocow) {
1578                         if (cow_start == (u64)-1)
1579                                 cow_start = cur_offset;
1580                         cur_offset = extent_end;
1581                         if (cur_offset > end)
1582                                 break;
1583                         path->slots[0]++;
1584                         goto next_slot;
1585                 }
1586
1587                 btrfs_release_path(path);
1588
1589                 /*
1590                  * COW range from cow_start to found_key.offset - 1. As the key
1591                  * will contain the beginning of the first extent that can be
1592                  * NOCOW, following one which needs to be COW'ed
1593                  */
1594                 if (cow_start != (u64)-1) {
1595                         ret = cow_file_range(inode, locked_page,
1596                                              cow_start, found_key.offset - 1,
1597                                              page_started, nr_written, 1);
1598                         if (ret) {
1599                                 if (nocow)
1600                                         btrfs_dec_nocow_writers(fs_info,
1601                                                                 disk_bytenr);
1602                                 goto error;
1603                         }
1604                         cow_start = (u64)-1;
1605                 }
1606
1607                 if (extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1608                         u64 orig_start = found_key.offset - extent_offset;
1609                         struct extent_map *em;
1610
1611                         em = create_io_em(inode, cur_offset, num_bytes,
1612                                           orig_start,
1613                                           disk_bytenr, /* block_start */
1614                                           num_bytes, /* block_len */
1615                                           disk_num_bytes, /* orig_block_len */
1616                                           ram_bytes, BTRFS_COMPRESS_NONE,
1617                                           BTRFS_ORDERED_PREALLOC);
1618                         if (IS_ERR(em)) {
1619                                 if (nocow)
1620                                         btrfs_dec_nocow_writers(fs_info,
1621                                                                 disk_bytenr);
1622                                 ret = PTR_ERR(em);
1623                                 goto error;
1624                         }
1625                         free_extent_map(em);
1626                         ret = btrfs_add_ordered_extent(inode, cur_offset,
1627                                                        disk_bytenr, num_bytes,
1628                                                        num_bytes,
1629                                                        BTRFS_ORDERED_PREALLOC);
1630                         if (ret) {
1631                                 btrfs_drop_extent_cache(BTRFS_I(inode),
1632                                                         cur_offset,
1633                                                         cur_offset + num_bytes - 1,
1634                                                         0);
1635                                 goto error;
1636                         }
1637                 } else {
1638                         ret = btrfs_add_ordered_extent(inode, cur_offset,
1639                                                        disk_bytenr, num_bytes,
1640                                                        num_bytes,
1641                                                        BTRFS_ORDERED_NOCOW);
1642                         if (ret)
1643                                 goto error;
1644                 }
1645
1646                 if (nocow)
1647                         btrfs_dec_nocow_writers(fs_info, disk_bytenr);
1648                 nocow = false;
1649
1650                 if (root->root_key.objectid ==
1651                     BTRFS_DATA_RELOC_TREE_OBJECTID)
1652                         /*
1653                          * Error handled later, as we must prevent
1654                          * extent_clear_unlock_delalloc() in error handler
1655                          * from freeing metadata of created ordered extent.
1656                          */
1657                         ret = btrfs_reloc_clone_csums(inode, cur_offset,
1658                                                       num_bytes);
1659
1660                 extent_clear_unlock_delalloc(inode, cur_offset,
1661                                              cur_offset + num_bytes - 1,
1662                                              locked_page, EXTENT_LOCKED |
1663                                              EXTENT_DELALLOC |
1664                                              EXTENT_CLEAR_DATA_RESV,
1665                                              PAGE_UNLOCK | PAGE_SET_PRIVATE2);
1666
1667                 cur_offset = extent_end;
1668
1669                 /*
1670                  * btrfs_reloc_clone_csums() error, now we're OK to call error
1671                  * handler, as metadata for created ordered extent will only
1672                  * be freed by btrfs_finish_ordered_io().
1673                  */
1674                 if (ret)
1675                         goto error;
1676                 if (cur_offset > end)
1677                         break;
1678         }
1679         btrfs_release_path(path);
1680
1681         if (cur_offset <= end && cow_start == (u64)-1)
1682                 cow_start = cur_offset;
1683
1684         if (cow_start != (u64)-1) {
1685                 cur_offset = end;
1686                 ret = cow_file_range(inode, locked_page, cow_start, end,
1687                                      page_started, nr_written, 1);
1688                 if (ret)
1689                         goto error;
1690         }
1691
1692 error:
1693         if (nocow)
1694                 btrfs_dec_nocow_writers(fs_info, disk_bytenr);
1695
1696         if (ret && cur_offset < end)
1697                 extent_clear_unlock_delalloc(inode, cur_offset, end,
1698                                              locked_page, EXTENT_LOCKED |
1699                                              EXTENT_DELALLOC | EXTENT_DEFRAG |
1700                                              EXTENT_DO_ACCOUNTING, PAGE_UNLOCK |
1701                                              PAGE_CLEAR_DIRTY |
1702                                              PAGE_SET_WRITEBACK |
1703                                              PAGE_END_WRITEBACK);
1704         btrfs_free_path(path);
1705         return ret;
1706 }
1707
1708 static inline int need_force_cow(struct inode *inode, u64 start, u64 end)
1709 {
1710
1711         if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) &&
1712             !(BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC))
1713                 return 0;
1714
1715         /*
1716          * @defrag_bytes is a hint value, no spinlock held here,
1717          * if is not zero, it means the file is defragging.
1718          * Force cow if given extent needs to be defragged.
1719          */
1720         if (BTRFS_I(inode)->defrag_bytes &&
1721             test_range_bit(&BTRFS_I(inode)->io_tree, start, end,
1722                            EXTENT_DEFRAG, 0, NULL))
1723                 return 1;
1724
1725         return 0;
1726 }
1727
1728 /*
1729  * Function to process delayed allocation (create CoW) for ranges which are
1730  * being touched for the first time.
1731  */
1732 int btrfs_run_delalloc_range(struct inode *inode, struct page *locked_page,
1733                 u64 start, u64 end, int *page_started, unsigned long *nr_written,
1734                 struct writeback_control *wbc)
1735 {
1736         int ret;
1737         int force_cow = need_force_cow(inode, start, end);
1738
1739         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW && !force_cow) {
1740                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1741                                          page_started, 1, nr_written);
1742         } else if (BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC && !force_cow) {
1743                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1744                                          page_started, 0, nr_written);
1745         } else if (!inode_can_compress(inode) ||
1746                    !inode_need_compress(inode, start, end)) {
1747                 ret = cow_file_range(inode, locked_page, start, end,
1748                                       page_started, nr_written, 1);
1749         } else {
1750                 set_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
1751                         &BTRFS_I(inode)->runtime_flags);
1752                 ret = cow_file_range_async(inode, wbc, locked_page, start, end,
1753                                            page_started, nr_written);
1754         }
1755         if (ret)
1756                 btrfs_cleanup_ordered_extents(inode, locked_page, start,
1757                                               end - start + 1);
1758         return ret;
1759 }
1760
1761 void btrfs_split_delalloc_extent(struct inode *inode,
1762                                  struct extent_state *orig, u64 split)
1763 {
1764         u64 size;
1765
1766         /* not delalloc, ignore it */
1767         if (!(orig->state & EXTENT_DELALLOC))
1768                 return;
1769
1770         size = orig->end - orig->start + 1;
1771         if (size > BTRFS_MAX_EXTENT_SIZE) {
1772                 u32 num_extents;
1773                 u64 new_size;
1774
1775                 /*
1776                  * See the explanation in btrfs_merge_delalloc_extent, the same
1777                  * applies here, just in reverse.
1778                  */
1779                 new_size = orig->end - split + 1;
1780                 num_extents = count_max_extents(new_size);
1781                 new_size = split - orig->start;
1782                 num_extents += count_max_extents(new_size);
1783                 if (count_max_extents(size) >= num_extents)
1784                         return;
1785         }
1786
1787         spin_lock(&BTRFS_I(inode)->lock);
1788         btrfs_mod_outstanding_extents(BTRFS_I(inode), 1);
1789         spin_unlock(&BTRFS_I(inode)->lock);
1790 }
1791
1792 /*
1793  * Handle merged delayed allocation extents so we can keep track of new extents
1794  * that are just merged onto old extents, such as when we are doing sequential
1795  * writes, so we can properly account for the metadata space we'll need.
1796  */
1797 void btrfs_merge_delalloc_extent(struct inode *inode, struct extent_state *new,
1798                                  struct extent_state *other)
1799 {
1800         u64 new_size, old_size;
1801         u32 num_extents;
1802
1803         /* not delalloc, ignore it */
1804         if (!(other->state & EXTENT_DELALLOC))
1805                 return;
1806
1807         if (new->start > other->start)
1808                 new_size = new->end - other->start + 1;
1809         else
1810                 new_size = other->end - new->start + 1;
1811
1812         /* we're not bigger than the max, unreserve the space and go */
1813         if (new_size <= BTRFS_MAX_EXTENT_SIZE) {
1814                 spin_lock(&BTRFS_I(inode)->lock);
1815                 btrfs_mod_outstanding_extents(BTRFS_I(inode), -1);
1816                 spin_unlock(&BTRFS_I(inode)->lock);
1817                 return;
1818         }
1819
1820         /*
1821          * We have to add up either side to figure out how many extents were
1822          * accounted for before we merged into one big extent.  If the number of
1823          * extents we accounted for is <= the amount we need for the new range
1824          * then we can return, otherwise drop.  Think of it like this
1825          *
1826          * [ 4k][MAX_SIZE]
1827          *
1828          * So we've grown the extent by a MAX_SIZE extent, this would mean we
1829          * need 2 outstanding extents, on one side we have 1 and the other side
1830          * we have 1 so they are == and we can return.  But in this case
1831          *
1832          * [MAX_SIZE+4k][MAX_SIZE+4k]
1833          *
1834          * Each range on their own accounts for 2 extents, but merged together
1835          * they are only 3 extents worth of accounting, so we need to drop in
1836          * this case.
1837          */
1838         old_size = other->end - other->start + 1;
1839         num_extents = count_max_extents(old_size);
1840         old_size = new->end - new->start + 1;
1841         num_extents += count_max_extents(old_size);
1842         if (count_max_extents(new_size) >= num_extents)
1843                 return;
1844
1845         spin_lock(&BTRFS_I(inode)->lock);
1846         btrfs_mod_outstanding_extents(BTRFS_I(inode), -1);
1847         spin_unlock(&BTRFS_I(inode)->lock);
1848 }
1849
1850 static void btrfs_add_delalloc_inodes(struct btrfs_root *root,
1851                                       struct inode *inode)
1852 {
1853         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1854
1855         spin_lock(&root->delalloc_lock);
1856         if (list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1857                 list_add_tail(&BTRFS_I(inode)->delalloc_inodes,
1858                               &root->delalloc_inodes);
1859                 set_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1860                         &BTRFS_I(inode)->runtime_flags);
1861                 root->nr_delalloc_inodes++;
1862                 if (root->nr_delalloc_inodes == 1) {
1863                         spin_lock(&fs_info->delalloc_root_lock);
1864                         BUG_ON(!list_empty(&root->delalloc_root));
1865                         list_add_tail(&root->delalloc_root,
1866                                       &fs_info->delalloc_roots);
1867                         spin_unlock(&fs_info->delalloc_root_lock);
1868                 }
1869         }
1870         spin_unlock(&root->delalloc_lock);
1871 }
1872
1873
1874 void __btrfs_del_delalloc_inode(struct btrfs_root *root,
1875                                 struct btrfs_inode *inode)
1876 {
1877         struct btrfs_fs_info *fs_info = root->fs_info;
1878
1879         if (!list_empty(&inode->delalloc_inodes)) {
1880                 list_del_init(&inode->delalloc_inodes);
1881                 clear_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1882                           &inode->runtime_flags);
1883                 root->nr_delalloc_inodes--;
1884                 if (!root->nr_delalloc_inodes) {
1885                         ASSERT(list_empty(&root->delalloc_inodes));
1886                         spin_lock(&fs_info->delalloc_root_lock);
1887                         BUG_ON(list_empty(&root->delalloc_root));
1888                         list_del_init(&root->delalloc_root);
1889                         spin_unlock(&fs_info->delalloc_root_lock);
1890                 }
1891         }
1892 }
1893
1894 static void btrfs_del_delalloc_inode(struct btrfs_root *root,
1895                                      struct btrfs_inode *inode)
1896 {
1897         spin_lock(&root->delalloc_lock);
1898         __btrfs_del_delalloc_inode(root, inode);
1899         spin_unlock(&root->delalloc_lock);
1900 }
1901
1902 /*
1903  * Properly track delayed allocation bytes in the inode and to maintain the
1904  * list of inodes that have pending delalloc work to be done.
1905  */
1906 void btrfs_set_delalloc_extent(struct inode *inode, struct extent_state *state,
1907                                unsigned *bits)
1908 {
1909         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1910
1911         if ((*bits & EXTENT_DEFRAG) && !(*bits & EXTENT_DELALLOC))
1912                 WARN_ON(1);
1913         /*
1914          * set_bit and clear bit hooks normally require _irqsave/restore
1915          * but in this case, we are only testing for the DELALLOC
1916          * bit, which is only set or cleared with irqs on
1917          */
1918         if (!(state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1919                 struct btrfs_root *root = BTRFS_I(inode)->root;
1920                 u64 len = state->end + 1 - state->start;
1921                 u32 num_extents = count_max_extents(len);
1922                 bool do_list = !btrfs_is_free_space_inode(BTRFS_I(inode));
1923
1924                 spin_lock(&BTRFS_I(inode)->lock);
1925                 btrfs_mod_outstanding_extents(BTRFS_I(inode), num_extents);
1926                 spin_unlock(&BTRFS_I(inode)->lock);
1927
1928                 /* For sanity tests */
1929                 if (btrfs_is_testing(fs_info))
1930                         return;
1931
1932                 percpu_counter_add_batch(&fs_info->delalloc_bytes, len,
1933                                          fs_info->delalloc_batch);
1934                 spin_lock(&BTRFS_I(inode)->lock);
1935                 BTRFS_I(inode)->delalloc_bytes += len;
1936                 if (*bits & EXTENT_DEFRAG)
1937                         BTRFS_I(inode)->defrag_bytes += len;
1938                 if (do_list && !test_bit(BTRFS_INODE_IN_DELALLOC_LIST,
1939                                          &BTRFS_I(inode)->runtime_flags))
1940                         btrfs_add_delalloc_inodes(root, inode);
1941                 spin_unlock(&BTRFS_I(inode)->lock);
1942         }
1943
1944         if (!(state->state & EXTENT_DELALLOC_NEW) &&
1945             (*bits & EXTENT_DELALLOC_NEW)) {
1946                 spin_lock(&BTRFS_I(inode)->lock);
1947                 BTRFS_I(inode)->new_delalloc_bytes += state->end + 1 -
1948                         state->start;
1949                 spin_unlock(&BTRFS_I(inode)->lock);
1950         }
1951 }
1952
1953 /*
1954  * Once a range is no longer delalloc this function ensures that proper
1955  * accounting happens.
1956  */
1957 void btrfs_clear_delalloc_extent(struct inode *vfs_inode,
1958                                  struct extent_state *state, unsigned *bits)
1959 {
1960         struct btrfs_inode *inode = BTRFS_I(vfs_inode);
1961         struct btrfs_fs_info *fs_info = btrfs_sb(vfs_inode->i_sb);
1962         u64 len = state->end + 1 - state->start;
1963         u32 num_extents = count_max_extents(len);
1964
1965         if ((state->state & EXTENT_DEFRAG) && (*bits & EXTENT_DEFRAG)) {
1966                 spin_lock(&inode->lock);
1967                 inode->defrag_bytes -= len;
1968                 spin_unlock(&inode->lock);
1969         }
1970
1971         /*
1972          * set_bit and clear bit hooks normally require _irqsave/restore
1973          * but in this case, we are only testing for the DELALLOC
1974          * bit, which is only set or cleared with irqs on
1975          */
1976         if ((state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1977                 struct btrfs_root *root = inode->root;
1978                 bool do_list = !btrfs_is_free_space_inode(inode);
1979
1980                 spin_lock(&inode->lock);
1981                 btrfs_mod_outstanding_extents(inode, -num_extents);
1982                 spin_unlock(&inode->lock);
1983
1984                 /*
1985                  * We don't reserve metadata space for space cache inodes so we
1986                  * don't need to call delalloc_release_metadata if there is an
1987                  * error.
1988                  */
1989                 if (*bits & EXTENT_CLEAR_META_RESV &&
1990                     root != fs_info->tree_root)
1991                         btrfs_delalloc_release_metadata(inode, len, false);
1992
1993                 /* For sanity tests. */
1994                 if (btrfs_is_testing(fs_info))
1995                         return;
1996
1997                 if (root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID &&
1998                     do_list && !(state->state & EXTENT_NORESERVE) &&
1999                     (*bits & EXTENT_CLEAR_DATA_RESV))
2000                         btrfs_free_reserved_data_space_noquota(
2001                                         &inode->vfs_inode,
2002                                         state->start, len);
2003
2004                 percpu_counter_add_batch(&fs_info->delalloc_bytes, -len,
2005                                          fs_info->delalloc_batch);
2006                 spin_lock(&inode->lock);
2007                 inode->delalloc_bytes -= len;
2008                 if (do_list && inode->delalloc_bytes == 0 &&
2009                     test_bit(BTRFS_INODE_IN_DELALLOC_LIST,
2010                                         &inode->runtime_flags))
2011                         btrfs_del_delalloc_inode(root, inode);
2012                 spin_unlock(&inode->lock);
2013         }
2014
2015         if ((state->state & EXTENT_DELALLOC_NEW) &&
2016             (*bits & EXTENT_DELALLOC_NEW)) {
2017                 spin_lock(&inode->lock);
2018                 ASSERT(inode->new_delalloc_bytes >= len);
2019                 inode->new_delalloc_bytes -= len;
2020                 spin_unlock(&inode->lock);
2021         }
2022 }
2023
2024 /*
2025  * btrfs_bio_fits_in_stripe - Checks whether the size of the given bio will fit
2026  * in a chunk's stripe. This function ensures that bios do not span a
2027  * stripe/chunk
2028  *
2029  * @page - The page we are about to add to the bio
2030  * @size - size we want to add to the bio
2031  * @bio - bio we want to ensure is smaller than a stripe
2032  * @bio_flags - flags of the bio
2033  *
2034  * return 1 if page cannot be added to the bio
2035  * return 0 if page can be added to the bio
2036  * return error otherwise
2037  */
2038 int btrfs_bio_fits_in_stripe(struct page *page, size_t size, struct bio *bio,
2039                              unsigned long bio_flags)
2040 {
2041         struct inode *inode = page->mapping->host;
2042         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2043         u64 logical = (u64)bio->bi_iter.bi_sector << 9;
2044         u64 length = 0;
2045         u64 map_length;
2046         int ret;
2047         struct btrfs_io_geometry geom;
2048
2049         if (bio_flags & EXTENT_BIO_COMPRESSED)
2050                 return 0;
2051
2052         length = bio->bi_iter.bi_size;
2053         map_length = length;
2054         ret = btrfs_get_io_geometry(fs_info, btrfs_op(bio), logical, map_length,
2055                                     &geom);
2056         if (ret < 0)
2057                 return ret;
2058
2059         if (geom.len < length + size)
2060                 return 1;
2061         return 0;
2062 }
2063
2064 /*
2065  * in order to insert checksums into the metadata in large chunks,
2066  * we wait until bio submission time.   All the pages in the bio are
2067  * checksummed and sums are attached onto the ordered extent record.
2068  *
2069  * At IO completion time the cums attached on the ordered extent record
2070  * are inserted into the btree
2071  */
2072 static blk_status_t btrfs_submit_bio_start(void *private_data, struct bio *bio,
2073                                     u64 bio_offset)
2074 {
2075         struct inode *inode = private_data;
2076         blk_status_t ret = 0;
2077
2078         ret = btrfs_csum_one_bio(inode, bio, 0, 0);
2079         BUG_ON(ret); /* -ENOMEM */
2080         return 0;
2081 }
2082
2083 /*
2084  * extent_io.c submission hook. This does the right thing for csum calculation
2085  * on write, or reading the csums from the tree before a read.
2086  *
2087  * Rules about async/sync submit,
2088  * a) read:                             sync submit
2089  *
2090  * b) write without checksum:           sync submit
2091  *
2092  * c) write with checksum:
2093  *    c-1) if bio is issued by fsync:   sync submit
2094  *         (sync_writers != 0)
2095  *
2096  *    c-2) if root is reloc root:       sync submit
2097  *         (only in case of buffered IO)
2098  *
2099  *    c-3) otherwise:                   async submit
2100  */
2101 static blk_status_t btrfs_submit_bio_hook(struct inode *inode, struct bio *bio,
2102                                           int mirror_num,
2103                                           unsigned long bio_flags)
2104
2105 {
2106         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2107         struct btrfs_root *root = BTRFS_I(inode)->root;
2108         enum btrfs_wq_endio_type metadata = BTRFS_WQ_ENDIO_DATA;
2109         blk_status_t ret = 0;
2110         int skip_sum;
2111         int async = !atomic_read(&BTRFS_I(inode)->sync_writers);
2112
2113         skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
2114
2115         if (btrfs_is_free_space_inode(BTRFS_I(inode)))
2116                 metadata = BTRFS_WQ_ENDIO_FREE_SPACE;
2117
2118         if (bio_op(bio) != REQ_OP_WRITE) {
2119                 ret = btrfs_bio_wq_end_io(fs_info, bio, metadata);
2120                 if (ret)
2121                         goto out;
2122
2123                 if (bio_flags & EXTENT_BIO_COMPRESSED) {
2124                         ret = btrfs_submit_compressed_read(inode, bio,
2125                                                            mirror_num,
2126                                                            bio_flags);
2127                         goto out;
2128                 } else if (!skip_sum) {
2129                         ret = btrfs_lookup_bio_sums(inode, bio, (u64)-1, NULL);
2130                         if (ret)
2131                                 goto out;
2132                 }
2133                 goto mapit;
2134         } else if (async && !skip_sum) {
2135                 /* csum items have already been cloned */
2136                 if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
2137                         goto mapit;
2138                 /* we're doing a write, do the async checksumming */
2139                 ret = btrfs_wq_submit_bio(fs_info, bio, mirror_num, bio_flags,
2140                                           0, inode, btrfs_submit_bio_start);
2141                 goto out;
2142         } else if (!skip_sum) {
2143                 ret = btrfs_csum_one_bio(inode, bio, 0, 0);
2144                 if (ret)
2145                         goto out;
2146         }
2147
2148 mapit:
2149         ret = btrfs_map_bio(fs_info, bio, mirror_num);
2150
2151 out:
2152         if (ret) {
2153                 bio->bi_status = ret;
2154                 bio_endio(bio);
2155         }
2156         return ret;
2157 }
2158
2159 /*
2160  * given a list of ordered sums record them in the inode.  This happens
2161  * at IO completion time based on sums calculated at bio submission time.
2162  */
2163 static noinline int add_pending_csums(struct btrfs_trans_handle *trans,
2164                              struct inode *inode, struct list_head *list)
2165 {
2166         struct btrfs_ordered_sum *sum;
2167         int ret;
2168
2169         list_for_each_entry(sum, list, list) {
2170                 trans->adding_csums = true;
2171                 ret = btrfs_csum_file_blocks(trans,
2172                        BTRFS_I(inode)->root->fs_info->csum_root, sum);
2173                 trans->adding_csums = false;
2174                 if (ret)
2175                         return ret;
2176         }
2177         return 0;
2178 }
2179
2180 int btrfs_set_extent_delalloc(struct inode *inode, u64 start, u64 end,
2181                               unsigned int extra_bits,
2182                               struct extent_state **cached_state)
2183 {
2184         WARN_ON(PAGE_ALIGNED(end));
2185         return set_extent_delalloc(&BTRFS_I(inode)->io_tree, start, end,
2186                                    extra_bits, cached_state);
2187 }
2188
2189 /* see btrfs_writepage_start_hook for details on why this is required */
2190 struct btrfs_writepage_fixup {
2191         struct page *page;
2192         struct btrfs_work work;
2193 };
2194
2195 static void btrfs_writepage_fixup_worker(struct btrfs_work *work)
2196 {
2197         struct btrfs_writepage_fixup *fixup;
2198         struct btrfs_ordered_extent *ordered;
2199         struct extent_state *cached_state = NULL;
2200         struct extent_changeset *data_reserved = NULL;
2201         struct page *page;
2202         struct inode *inode;
2203         u64 page_start;
2204         u64 page_end;
2205         int ret;
2206
2207         fixup = container_of(work, struct btrfs_writepage_fixup, work);
2208         page = fixup->page;
2209 again:
2210         lock_page(page);
2211         if (!page->mapping || !PageDirty(page) || !PageChecked(page)) {
2212                 ClearPageChecked(page);
2213                 goto out_page;
2214         }
2215
2216         inode = page->mapping->host;
2217         page_start = page_offset(page);
2218         page_end = page_offset(page) + PAGE_SIZE - 1;
2219
2220         lock_extent_bits(&BTRFS_I(inode)->io_tree, page_start, page_end,
2221                          &cached_state);
2222
2223         /* already ordered? We're done */
2224         if (PagePrivate2(page))
2225                 goto out;
2226
2227         ordered = btrfs_lookup_ordered_range(BTRFS_I(inode), page_start,
2228                                         PAGE_SIZE);
2229         if (ordered) {
2230                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start,
2231                                      page_end, &cached_state);
2232                 unlock_page(page);
2233                 btrfs_start_ordered_extent(inode, ordered, 1);
2234                 btrfs_put_ordered_extent(ordered);
2235                 goto again;
2236         }
2237
2238         ret = btrfs_delalloc_reserve_space(inode, &data_reserved, page_start,
2239                                            PAGE_SIZE);
2240         if (ret) {
2241                 mapping_set_error(page->mapping, ret);
2242                 end_extent_writepage(page, ret, page_start, page_end);
2243                 ClearPageChecked(page);
2244                 goto out;
2245          }
2246
2247         ret = btrfs_set_extent_delalloc(inode, page_start, page_end, 0,
2248                                         &cached_state);
2249         if (ret) {
2250                 mapping_set_error(page->mapping, ret);
2251                 end_extent_writepage(page, ret, page_start, page_end);
2252                 ClearPageChecked(page);
2253                 goto out_reserved;
2254         }
2255
2256         ClearPageChecked(page);
2257         set_page_dirty(page);
2258 out_reserved:
2259         btrfs_delalloc_release_extents(BTRFS_I(inode), PAGE_SIZE);
2260         if (ret)
2261                 btrfs_delalloc_release_space(inode, data_reserved, page_start,
2262                                              PAGE_SIZE, true);
2263 out:
2264         unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start, page_end,
2265                              &cached_state);
2266 out_page:
2267         unlock_page(page);
2268         put_page(page);
2269         kfree(fixup);
2270         extent_changeset_free(data_reserved);
2271 }
2272
2273 /*
2274  * There are a few paths in the higher layers of the kernel that directly
2275  * set the page dirty bit without asking the filesystem if it is a
2276  * good idea.  This causes problems because we want to make sure COW
2277  * properly happens and the data=ordered rules are followed.
2278  *
2279  * In our case any range that doesn't have the ORDERED bit set
2280  * hasn't been properly setup for IO.  We kick off an async process
2281  * to fix it up.  The async helper will wait for ordered extents, set
2282  * the delalloc bit and make it safe to write the page.
2283  */
2284 int btrfs_writepage_cow_fixup(struct page *page, u64 start, u64 end)
2285 {
2286         struct inode *inode = page->mapping->host;
2287         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2288         struct btrfs_writepage_fixup *fixup;
2289
2290         /* this page is properly in the ordered list */
2291         if (TestClearPagePrivate2(page))
2292                 return 0;
2293
2294         if (PageChecked(page))
2295                 return -EAGAIN;
2296
2297         fixup = kzalloc(sizeof(*fixup), GFP_NOFS);
2298         if (!fixup)
2299                 return -EAGAIN;
2300
2301         SetPageChecked(page);
2302         get_page(page);
2303         btrfs_init_work(&fixup->work, btrfs_writepage_fixup_worker, NULL, NULL);
2304         fixup->page = page;
2305         btrfs_queue_work(fs_info->fixup_workers, &fixup->work);
2306         return -EBUSY;
2307 }
2308
2309 static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
2310                                        struct inode *inode, u64 file_pos,
2311                                        u64 disk_bytenr, u64 disk_num_bytes,
2312                                        u64 num_bytes, u64 ram_bytes,
2313                                        u8 compression, u8 encryption,
2314                                        u16 other_encoding, int extent_type)
2315 {
2316         struct btrfs_root *root = BTRFS_I(inode)->root;
2317         struct btrfs_file_extent_item *fi;
2318         struct btrfs_path *path;
2319         struct extent_buffer *leaf;
2320         struct btrfs_key ins;
2321         u64 qg_released;
2322         int extent_inserted = 0;
2323         int ret;
2324
2325         path = btrfs_alloc_path();
2326         if (!path)
2327                 return -ENOMEM;
2328
2329         /*
2330          * we may be replacing one extent in the tree with another.
2331          * The new extent is pinned in the extent map, and we don't want
2332          * to drop it from the cache until it is completely in the btree.
2333          *
2334          * So, tell btrfs_drop_extents to leave this extent in the cache.
2335          * the caller is expected to unpin it and allow it to be merged
2336          * with the others.
2337          */
2338         ret = __btrfs_drop_extents(trans, root, inode, path, file_pos,
2339                                    file_pos + num_bytes, NULL, 0,
2340                                    1, sizeof(*fi), &extent_inserted);
2341         if (ret)
2342                 goto out;
2343
2344         if (!extent_inserted) {
2345                 ins.objectid = btrfs_ino(BTRFS_I(inode));
2346                 ins.offset = file_pos;
2347                 ins.type = BTRFS_EXTENT_DATA_KEY;
2348
2349                 path->leave_spinning = 1;
2350                 ret = btrfs_insert_empty_item(trans, root, path, &ins,
2351                                               sizeof(*fi));
2352                 if (ret)
2353                         goto out;
2354         }
2355         leaf = path->nodes[0];
2356         fi = btrfs_item_ptr(leaf, path->slots[0],
2357                             struct btrfs_file_extent_item);
2358         btrfs_set_file_extent_generation(leaf, fi, trans->transid);
2359         btrfs_set_file_extent_type(leaf, fi, extent_type);
2360         btrfs_set_file_extent_disk_bytenr(leaf, fi, disk_bytenr);
2361         btrfs_set_file_extent_disk_num_bytes(leaf, fi, disk_num_bytes);
2362         btrfs_set_file_extent_offset(leaf, fi, 0);
2363         btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
2364         btrfs_set_file_extent_ram_bytes(leaf, fi, ram_bytes);
2365         btrfs_set_file_extent_compression(leaf, fi, compression);
2366         btrfs_set_file_extent_encryption(leaf, fi, encryption);
2367         btrfs_set_file_extent_other_encoding(leaf, fi, other_encoding);
2368
2369         btrfs_mark_buffer_dirty(leaf);
2370         btrfs_release_path(path);
2371
2372         inode_add_bytes(inode, num_bytes);
2373
2374         ins.objectid = disk_bytenr;
2375         ins.offset = disk_num_bytes;
2376         ins.type = BTRFS_EXTENT_ITEM_KEY;
2377
2378         /*
2379          * Release the reserved range from inode dirty range map, as it is
2380          * already moved into delayed_ref_head
2381          */
2382         ret = btrfs_qgroup_release_data(inode, file_pos, ram_bytes);
2383         if (ret < 0)
2384                 goto out;
2385         qg_released = ret;
2386         ret = btrfs_alloc_reserved_file_extent(trans, root,
2387                                                btrfs_ino(BTRFS_I(inode)),
2388                                                file_pos, qg_released, &ins);
2389 out:
2390         btrfs_free_path(path);
2391
2392         return ret;
2393 }
2394
2395 static void btrfs_release_delalloc_bytes(struct btrfs_fs_info *fs_info,
2396                                          u64 start, u64 len)
2397 {
2398         struct btrfs_block_group *cache;
2399
2400         cache = btrfs_lookup_block_group(fs_info, start);
2401         ASSERT(cache);
2402
2403         spin_lock(&cache->lock);
2404         cache->delalloc_bytes -= len;
2405         spin_unlock(&cache->lock);
2406
2407         btrfs_put_block_group(cache);
2408 }
2409
2410 /* as ordered data IO finishes, this gets called so we can finish
2411  * an ordered extent if the range of bytes in the file it covers are
2412  * fully written.
2413  */
2414 static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent)
2415 {
2416         struct inode *inode = ordered_extent->inode;
2417         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2418         struct btrfs_root *root = BTRFS_I(inode)->root;
2419         struct btrfs_trans_handle *trans = NULL;
2420         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2421         struct extent_state *cached_state = NULL;
2422         u64 start, end;
2423         int compress_type = 0;
2424         int ret = 0;
2425         u64 logical_len = ordered_extent->num_bytes;
2426         bool freespace_inode;
2427         bool truncated = false;
2428         bool range_locked = false;
2429         bool clear_new_delalloc_bytes = false;
2430         bool clear_reserved_extent = true;
2431         unsigned int clear_bits;
2432
2433         start = ordered_extent->file_offset;
2434         end = start + ordered_extent->num_bytes - 1;
2435
2436         if (!test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags) &&
2437             !test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags) &&
2438             !test_bit(BTRFS_ORDERED_DIRECT, &ordered_extent->flags))
2439                 clear_new_delalloc_bytes = true;
2440
2441         freespace_inode = btrfs_is_free_space_inode(BTRFS_I(inode));
2442
2443         if (test_bit(BTRFS_ORDERED_IOERR, &ordered_extent->flags)) {
2444                 ret = -EIO;
2445                 goto out;
2446         }
2447
2448         btrfs_free_io_failure_record(BTRFS_I(inode), start, end);
2449
2450         if (test_bit(BTRFS_ORDERED_TRUNCATED, &ordered_extent->flags)) {
2451                 truncated = true;
2452                 logical_len = ordered_extent->truncated_len;
2453                 /* Truncated the entire extent, don't bother adding */
2454                 if (!logical_len)
2455                         goto out;
2456         }
2457
2458         if (test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags)) {
2459                 BUG_ON(!list_empty(&ordered_extent->list)); /* Logic error */
2460
2461                 /*
2462                  * For mwrite(mmap + memset to write) case, we still reserve
2463                  * space for NOCOW range.
2464                  * As NOCOW won't cause a new delayed ref, just free the space
2465                  */
2466                 btrfs_qgroup_free_data(inode, NULL, start,
2467                                        ordered_extent->num_bytes);
2468                 btrfs_ordered_update_i_size(inode, 0, ordered_extent);
2469                 if (freespace_inode)
2470                         trans = btrfs_join_transaction_spacecache(root);
2471                 else
2472                         trans = btrfs_join_transaction(root);
2473                 if (IS_ERR(trans)) {
2474                         ret = PTR_ERR(trans);
2475                         trans = NULL;
2476                         goto out;
2477                 }
2478                 trans->block_rsv = &BTRFS_I(inode)->block_rsv;
2479                 ret = btrfs_update_inode_fallback(trans, root, inode);
2480                 if (ret) /* -ENOMEM or corruption */
2481                         btrfs_abort_transaction(trans, ret);
2482                 goto out;
2483         }
2484
2485         range_locked = true;
2486         lock_extent_bits(io_tree, start, end, &cached_state);
2487
2488         if (freespace_inode)
2489                 trans = btrfs_join_transaction_spacecache(root);
2490         else
2491                 trans = btrfs_join_transaction(root);
2492         if (IS_ERR(trans)) {
2493                 ret = PTR_ERR(trans);
2494                 trans = NULL;
2495                 goto out;
2496         }
2497
2498         trans->block_rsv = &BTRFS_I(inode)->block_rsv;
2499
2500         if (test_bit(BTRFS_ORDERED_COMPRESSED, &ordered_extent->flags))
2501                 compress_type = ordered_extent->compress_type;
2502         if (test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags)) {
2503                 BUG_ON(compress_type);
2504                 btrfs_qgroup_free_data(inode, NULL, start,
2505                                        ordered_extent->num_bytes);
2506                 ret = btrfs_mark_extent_written(trans, BTRFS_I(inode),
2507                                                 ordered_extent->file_offset,
2508                                                 ordered_extent->file_offset +
2509                                                 logical_len);
2510         } else {
2511                 BUG_ON(root == fs_info->tree_root);
2512                 ret = insert_reserved_file_extent(trans, inode, start,
2513                                                 ordered_extent->disk_bytenr,
2514                                                 ordered_extent->disk_num_bytes,
2515                                                 logical_len, logical_len,
2516                                                 compress_type, 0, 0,
2517                                                 BTRFS_FILE_EXTENT_REG);
2518                 if (!ret) {
2519                         clear_reserved_extent = false;
2520                         btrfs_release_delalloc_bytes(fs_info,
2521                                                 ordered_extent->disk_bytenr,
2522                                                 ordered_extent->disk_num_bytes);
2523                 }
2524         }
2525         unpin_extent_cache(&BTRFS_I(inode)->extent_tree,
2526                            ordered_extent->file_offset,
2527                            ordered_extent->num_bytes, trans->transid);
2528         if (ret < 0) {
2529                 btrfs_abort_transaction(trans, ret);
2530                 goto out;
2531         }
2532
2533         ret = add_pending_csums(trans, inode, &ordered_extent->list);
2534         if (ret) {
2535                 btrfs_abort_transaction(trans, ret);
2536                 goto out;
2537         }
2538
2539         btrfs_ordered_update_i_size(inode, 0, ordered_extent);
2540         ret = btrfs_update_inode_fallback(trans, root, inode);
2541         if (ret) { /* -ENOMEM or corruption */
2542                 btrfs_abort_transaction(trans, ret);
2543                 goto out;
2544         }
2545         ret = 0;
2546 out:
2547         clear_bits = EXTENT_DEFRAG;
2548         if (range_locked)
2549                 clear_bits |= EXTENT_LOCKED;
2550         if (clear_new_delalloc_bytes)
2551                 clear_bits |= EXTENT_DELALLOC_NEW;
2552         clear_extent_bit(&BTRFS_I(inode)->io_tree, start, end, clear_bits,
2553                          (clear_bits & EXTENT_LOCKED) ? 1 : 0, 0,
2554                          &cached_state);
2555
2556         if (trans)
2557                 btrfs_end_transaction(trans);
2558
2559         if (ret || truncated) {
2560                 u64 unwritten_start = start;
2561
2562                 if (truncated)
2563                         unwritten_start += logical_len;
2564                 clear_extent_uptodate(io_tree, unwritten_start, end, NULL);
2565
2566                 /* Drop the cache for the part of the extent we didn't write. */
2567                 btrfs_drop_extent_cache(BTRFS_I(inode), unwritten_start, end, 0);
2568
2569                 /*
2570                  * If the ordered extent had an IOERR or something else went
2571                  * wrong we need to return the space for this ordered extent
2572                  * back to the allocator.  We only free the extent in the
2573                  * truncated case if we didn't write out the extent at all.
2574                  *
2575                  * If we made it past insert_reserved_file_extent before we
2576                  * errored out then we don't need to do this as the accounting
2577                  * has already been done.
2578                  */
2579                 if ((ret || !logical_len) &&
2580                     clear_reserved_extent &&
2581                     !test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags) &&
2582                     !test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags)) {
2583                         /*
2584                          * Discard the range before returning it back to the
2585                          * free space pool
2586                          */
2587                         if (ret && btrfs_test_opt(fs_info, DISCARD_SYNC))
2588                                 btrfs_discard_extent(fs_info,
2589                                                 ordered_extent->disk_bytenr,
2590                                                 ordered_extent->disk_num_bytes,
2591                                                 NULL);
2592                         btrfs_free_reserved_extent(fs_info,
2593                                         ordered_extent->disk_bytenr,
2594                                         ordered_extent->disk_num_bytes, 1);
2595                 }
2596         }
2597
2598         /*
2599          * This needs to be done to make sure anybody waiting knows we are done
2600          * updating everything for this ordered extent.
2601          */
2602         btrfs_remove_ordered_extent(inode, ordered_extent);
2603
2604         /* once for us */
2605         btrfs_put_ordered_extent(ordered_extent);
2606         /* once for the tree */
2607         btrfs_put_ordered_extent(ordered_extent);
2608
2609         return ret;
2610 }
2611
2612 static void finish_ordered_fn(struct btrfs_work *work)
2613 {
2614         struct btrfs_ordered_extent *ordered_extent;
2615         ordered_extent = container_of(work, struct btrfs_ordered_extent, work);
2616         btrfs_finish_ordered_io(ordered_extent);
2617 }
2618
2619 void btrfs_writepage_endio_finish_ordered(struct page *page, u64 start,
2620                                           u64 end, int uptodate)
2621 {
2622         struct inode *inode = page->mapping->host;
2623         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2624         struct btrfs_ordered_extent *ordered_extent = NULL;
2625         struct btrfs_workqueue *wq;
2626
2627         trace_btrfs_writepage_end_io_hook(page, start, end, uptodate);
2628
2629         ClearPagePrivate2(page);
2630         if (!btrfs_dec_test_ordered_pending(inode, &ordered_extent, start,
2631                                             end - start + 1, uptodate))
2632                 return;
2633
2634         if (btrfs_is_free_space_inode(BTRFS_I(inode)))
2635                 wq = fs_info->endio_freespace_worker;
2636         else
2637                 wq = fs_info->endio_write_workers;
2638
2639         btrfs_init_work(&ordered_extent->work, finish_ordered_fn, NULL, NULL);
2640         btrfs_queue_work(wq, &ordered_extent->work);
2641 }
2642
2643 static int __readpage_endio_check(struct inode *inode,
2644                                   struct btrfs_io_bio *io_bio,
2645                                   int icsum, struct page *page,
2646                                   int pgoff, u64 start, size_t len)
2647 {
2648         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2649         SHASH_DESC_ON_STACK(shash, fs_info->csum_shash);
2650         char *kaddr;
2651         u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
2652         u8 *csum_expected;
2653         u8 csum[BTRFS_CSUM_SIZE];
2654
2655         csum_expected = ((u8 *)io_bio->csum) + icsum * csum_size;
2656
2657         kaddr = kmap_atomic(page);
2658         shash->tfm = fs_info->csum_shash;
2659
2660         crypto_shash_init(shash);
2661         crypto_shash_update(shash, kaddr + pgoff, len);
2662         crypto_shash_final(shash, csum);
2663
2664         if (memcmp(csum, csum_expected, csum_size))
2665                 goto zeroit;
2666
2667         kunmap_atomic(kaddr);
2668         return 0;
2669 zeroit:
2670         btrfs_print_data_csum_error(BTRFS_I(inode), start, csum, csum_expected,
2671                                     io_bio->mirror_num);
2672         memset(kaddr + pgoff, 1, len);
2673         flush_dcache_page(page);
2674         kunmap_atomic(kaddr);
2675         return -EIO;
2676 }
2677
2678 /*
2679  * when reads are done, we need to check csums to verify the data is correct
2680  * if there's a match, we allow the bio to finish.  If not, the code in
2681  * extent_io.c will try to find good copies for us.
2682  */
2683 static int btrfs_readpage_end_io_hook(struct btrfs_io_bio *io_bio,
2684                                       u64 phy_offset, struct page *page,
2685                                       u64 start, u64 end, int mirror)
2686 {
2687         size_t offset = start - page_offset(page);
2688         struct inode *inode = page->mapping->host;
2689         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2690         struct btrfs_root *root = BTRFS_I(inode)->root;
2691
2692         if (PageChecked(page)) {
2693                 ClearPageChecked(page);
2694                 return 0;
2695         }
2696
2697         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)
2698                 return 0;
2699
2700         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID &&
2701             test_range_bit(io_tree, start, end, EXTENT_NODATASUM, 1, NULL)) {
2702                 clear_extent_bits(io_tree, start, end, EXTENT_NODATASUM);
2703                 return 0;
2704         }
2705
2706         phy_offset >>= inode->i_sb->s_blocksize_bits;
2707         return __readpage_endio_check(inode, io_bio, phy_offset, page, offset,
2708                                       start, (size_t)(end - start + 1));
2709 }
2710
2711 /*
2712  * btrfs_add_delayed_iput - perform a delayed iput on @inode
2713  *
2714  * @inode: The inode we want to perform iput on
2715  *
2716  * This function uses the generic vfs_inode::i_count to track whether we should
2717  * just decrement it (in case it's > 1) or if this is the last iput then link
2718  * the inode to the delayed iput machinery. Delayed iputs are processed at
2719  * transaction commit time/superblock commit/cleaner kthread.
2720  */
2721 void btrfs_add_delayed_iput(struct inode *inode)
2722 {
2723         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2724         struct btrfs_inode *binode = BTRFS_I(inode);
2725
2726         if (atomic_add_unless(&inode->i_count, -1, 1))
2727                 return;
2728
2729         atomic_inc(&fs_info->nr_delayed_iputs);
2730         spin_lock(&fs_info->delayed_iput_lock);
2731         ASSERT(list_empty(&binode->delayed_iput));
2732         list_add_tail(&binode->delayed_iput, &fs_info->delayed_iputs);
2733         spin_unlock(&fs_info->delayed_iput_lock);
2734         if (!test_bit(BTRFS_FS_CLEANER_RUNNING, &fs_info->flags))
2735                 wake_up_process(fs_info->cleaner_kthread);
2736 }
2737
2738 static void run_delayed_iput_locked(struct btrfs_fs_info *fs_info,
2739                                     struct btrfs_inode *inode)
2740 {
2741         list_del_init(&inode->delayed_iput);
2742         spin_unlock(&fs_info->delayed_iput_lock);
2743         iput(&inode->vfs_inode);
2744         if (atomic_dec_and_test(&fs_info->nr_delayed_iputs))
2745                 wake_up(&fs_info->delayed_iputs_wait);
2746         spin_lock(&fs_info->delayed_iput_lock);
2747 }
2748
2749 static void btrfs_run_delayed_iput(struct btrfs_fs_info *fs_info,
2750                                    struct btrfs_inode *inode)
2751 {
2752         if (!list_empty(&inode->delayed_iput)) {
2753                 spin_lock(&fs_info->delayed_iput_lock);
2754                 if (!list_empty(&inode->delayed_iput))
2755                         run_delayed_iput_locked(fs_info, inode);
2756                 spin_unlock(&fs_info->delayed_iput_lock);
2757         }
2758 }
2759
2760 void btrfs_run_delayed_iputs(struct btrfs_fs_info *fs_info)
2761 {
2762
2763         spin_lock(&fs_info->delayed_iput_lock);
2764         while (!list_empty(&fs_info->delayed_iputs)) {
2765                 struct btrfs_inode *inode;
2766
2767                 inode = list_first_entry(&fs_info->delayed_iputs,
2768                                 struct btrfs_inode, delayed_iput);
2769                 run_delayed_iput_locked(fs_info, inode);
2770         }
2771         spin_unlock(&fs_info->delayed_iput_lock);
2772 }
2773
2774 /**
2775  * btrfs_wait_on_delayed_iputs - wait on the delayed iputs to be done running
2776  * @fs_info - the fs_info for this fs
2777  * @return - EINTR if we were killed, 0 if nothing's pending
2778  *
2779  * This will wait on any delayed iputs that are currently running with KILLABLE
2780  * set.  Once they are all done running we will return, unless we are killed in
2781  * which case we return EINTR. This helps in user operations like fallocate etc
2782  * that might get blocked on the iputs.
2783  */
2784 int btrfs_wait_on_delayed_iputs(struct btrfs_fs_info *fs_info)
2785 {
2786         int ret = wait_event_killable(fs_info->delayed_iputs_wait,
2787                         atomic_read(&fs_info->nr_delayed_iputs) == 0);
2788         if (ret)
2789                 return -EINTR;
2790         return 0;
2791 }
2792
2793 /*
2794  * This creates an orphan entry for the given inode in case something goes wrong
2795  * in the middle of an unlink.
2796  */
2797 int btrfs_orphan_add(struct btrfs_trans_handle *trans,
2798                      struct btrfs_inode *inode)
2799 {
2800         int ret;
2801
2802         ret = btrfs_insert_orphan_item(trans, inode->root, btrfs_ino(inode));
2803         if (ret && ret != -EEXIST) {
2804                 btrfs_abort_transaction(trans, ret);
2805                 return ret;
2806         }
2807
2808         return 0;
2809 }
2810
2811 /*
2812  * We have done the delete so we can go ahead and remove the orphan item for
2813  * this particular inode.
2814  */
2815 static int btrfs_orphan_del(struct btrfs_trans_handle *trans,
2816                             struct btrfs_inode *inode)
2817 {
2818         return btrfs_del_orphan_item(trans, inode->root, btrfs_ino(inode));
2819 }
2820
2821 /*
2822  * this cleans up any orphans that may be left on the list from the last use
2823  * of this root.
2824  */
2825 int btrfs_orphan_cleanup(struct btrfs_root *root)
2826 {
2827         struct btrfs_fs_info *fs_info = root->fs_info;
2828         struct btrfs_path *path;
2829         struct extent_buffer *leaf;
2830         struct btrfs_key key, found_key;
2831         struct btrfs_trans_handle *trans;
2832         struct inode *inode;
2833         u64 last_objectid = 0;
2834         int ret = 0, nr_unlink = 0;
2835
2836         if (cmpxchg(&root->orphan_cleanup_state, 0, ORPHAN_CLEANUP_STARTED))
2837                 return 0;
2838
2839         path = btrfs_alloc_path();
2840         if (!path) {
2841                 ret = -ENOMEM;
2842                 goto out;
2843         }
2844         path->reada = READA_BACK;
2845
2846         key.objectid = BTRFS_ORPHAN_OBJECTID;
2847         key.type = BTRFS_ORPHAN_ITEM_KEY;
2848         key.offset = (u64)-1;
2849
2850         while (1) {
2851                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2852                 if (ret < 0)
2853                         goto out;
2854
2855                 /*
2856                  * if ret == 0 means we found what we were searching for, which
2857                  * is weird, but possible, so only screw with path if we didn't
2858                  * find the key and see if we have stuff that matches
2859                  */
2860                 if (ret > 0) {
2861                         ret = 0;
2862                         if (path->slots[0] == 0)
2863                                 break;
2864                         path->slots[0]--;
2865                 }
2866
2867                 /* pull out the item */
2868                 leaf = path->nodes[0];
2869                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2870
2871                 /* make sure the item matches what we want */
2872                 if (found_key.objectid != BTRFS_ORPHAN_OBJECTID)
2873                         break;
2874                 if (found_key.type != BTRFS_ORPHAN_ITEM_KEY)
2875                         break;
2876
2877                 /* release the path since we're done with it */
2878                 btrfs_release_path(path);
2879
2880                 /*
2881                  * this is where we are basically btrfs_lookup, without the
2882                  * crossing root thing.  we store the inode number in the
2883                  * offset of the orphan item.
2884                  */
2885
2886                 if (found_key.offset == last_objectid) {
2887                         btrfs_err(fs_info,
2888                                   "Error removing orphan entry, stopping orphan cleanup");
2889                         ret = -EINVAL;
2890                         goto out;
2891                 }
2892
2893                 last_objectid = found_key.offset;
2894
2895                 found_key.objectid = found_key.offset;
2896                 found_key.type = BTRFS_INODE_ITEM_KEY;
2897                 found_key.offset = 0;
2898                 inode = btrfs_iget(fs_info->sb, &found_key, root);
2899                 ret = PTR_ERR_OR_ZERO(inode);
2900                 if (ret && ret != -ENOENT)
2901                         goto out;
2902
2903                 if (ret == -ENOENT && root == fs_info->tree_root) {
2904                         struct btrfs_root *dead_root;
2905                         struct btrfs_fs_info *fs_info = root->fs_info;
2906                         int is_dead_root = 0;
2907
2908                         /*
2909                          * this is an orphan in the tree root. Currently these
2910                          * could come from 2 sources:
2911                          *  a) a snapshot deletion in progress
2912                          *  b) a free space cache inode
2913                          * We need to distinguish those two, as the snapshot
2914                          * orphan must not get deleted.
2915                          * find_dead_roots already ran before us, so if this
2916                          * is a snapshot deletion, we should find the root
2917                          * in the dead_roots list
2918                          */
2919                         spin_lock(&fs_info->trans_lock);
2920                         list_for_each_entry(dead_root, &fs_info->dead_roots,
2921                                             root_list) {
2922                                 if (dead_root->root_key.objectid ==
2923                                     found_key.objectid) {
2924                                         is_dead_root = 1;
2925                                         break;
2926                                 }
2927                         }
2928                         spin_unlock(&fs_info->trans_lock);
2929                         if (is_dead_root) {
2930                                 /* prevent this orphan from being found again */
2931                                 key.offset = found_key.objectid - 1;
2932                                 continue;
2933                         }
2934
2935                 }
2936
2937                 /*
2938                  * If we have an inode with links, there are a couple of
2939                  * possibilities. Old kernels (before v3.12) used to create an
2940                  * orphan item for truncate indicating that there were possibly
2941                  * extent items past i_size that needed to be deleted. In v3.12,
2942                  * truncate was changed to update i_size in sync with the extent
2943                  * items, but the (useless) orphan item was still created. Since
2944                  * v4.18, we don't create the orphan item for truncate at all.
2945                  *
2946                  * So, this item could mean that we need to do a truncate, but
2947                  * only if this filesystem was last used on a pre-v3.12 kernel
2948                  * and was not cleanly unmounted. The odds of that are quite
2949                  * slim, and it's a pain to do the truncate now, so just delete
2950                  * the orphan item.
2951                  *
2952                  * It's also possible that this orphan item was supposed to be
2953                  * deleted but wasn't. The inode number may have been reused,
2954                  * but either way, we can delete the orphan item.
2955                  */
2956                 if (ret == -ENOENT || inode->i_nlink) {
2957                         if (!ret)
2958                                 iput(inode);
2959                         trans = btrfs_start_transaction(root, 1);
2960                         if (IS_ERR(trans)) {
2961                                 ret = PTR_ERR(trans);
2962                                 goto out;
2963                         }
2964                         btrfs_debug(fs_info, "auto deleting %Lu",
2965                                     found_key.objectid);
2966                         ret = btrfs_del_orphan_item(trans, root,
2967                                                     found_key.objectid);
2968                         btrfs_end_transaction(trans);
2969                         if (ret)
2970                                 goto out;
2971                         continue;
2972                 }
2973
2974                 nr_unlink++;
2975
2976                 /* this will do delete_inode and everything for us */
2977                 iput(inode);
2978         }
2979         /* release the path since we're done with it */
2980         btrfs_release_path(path);
2981
2982         root->orphan_cleanup_state = ORPHAN_CLEANUP_DONE;
2983
2984         if (test_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state)) {
2985                 trans = btrfs_join_transaction(root);
2986                 if (!IS_ERR(trans))
2987                         btrfs_end_transaction(trans);
2988         }
2989
2990         if (nr_unlink)
2991                 btrfs_debug(fs_info, "unlinked %d orphans", nr_unlink);
2992
2993 out:
2994         if (ret)
2995                 btrfs_err(fs_info, "could not do orphan cleanup %d", ret);
2996         btrfs_free_path(path);
2997         return ret;
2998 }
2999
3000 /*
3001  * very simple check to peek ahead in the leaf looking for xattrs.  If we
3002  * don't find any xattrs, we know there can't be any acls.
3003  *
3004  * slot is the slot the inode is in, objectid is the objectid of the inode
3005  */
3006 static noinline int acls_after_inode_item(struct extent_buffer *leaf,
3007                                           int slot, u64 objectid,
3008                                           int *first_xattr_slot)
3009 {
3010         u32 nritems = btrfs_header_nritems(leaf);
3011         struct btrfs_key found_key;
3012         static u64 xattr_access = 0;
3013         static u64 xattr_default = 0;
3014         int scanned = 0;
3015
3016         if (!xattr_access) {
3017                 xattr_access = btrfs_name_hash(XATTR_NAME_POSIX_ACL_ACCESS,
3018                                         strlen(XATTR_NAME_POSIX_ACL_ACCESS));
3019                 xattr_default = btrfs_name_hash(XATTR_NAME_POSIX_ACL_DEFAULT,
3020                                         strlen(XATTR_NAME_POSIX_ACL_DEFAULT));
3021         }
3022
3023         slot++;
3024         *first_xattr_slot = -1;
3025         while (slot < nritems) {
3026                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
3027
3028                 /* we found a different objectid, there must not be acls */
3029                 if (found_key.objectid != objectid)
3030                         return 0;
3031
3032                 /* we found an xattr, assume we've got an acl */
3033                 if (found_key.type == BTRFS_XATTR_ITEM_KEY) {
3034                         if (*first_xattr_slot == -1)
3035                                 *first_xattr_slot = slot;
3036                         if (found_key.offset == xattr_access ||
3037                             found_key.offset == xattr_default)
3038                                 return 1;
3039                 }
3040
3041                 /*
3042                  * we found a key greater than an xattr key, there can't
3043                  * be any acls later on
3044                  */
3045                 if (found_key.type > BTRFS_XATTR_ITEM_KEY)
3046                         return 0;
3047
3048                 slot++;
3049                 scanned++;
3050
3051                 /*
3052                  * it goes inode, inode backrefs, xattrs, extents,
3053                  * so if there are a ton of hard links to an inode there can
3054                  * be a lot of backrefs.  Don't waste time searching too hard,
3055                  * this is just an optimization
3056                  */
3057                 if (scanned >= 8)
3058                         break;
3059         }
3060         /* we hit the end of the leaf before we found an xattr or
3061          * something larger than an xattr.  We have to assume the inode
3062          * has acls
3063          */
3064         if (*first_xattr_slot == -1)
3065                 *first_xattr_slot = slot;
3066         return 1;
3067 }
3068
3069 /*
3070  * read an inode from the btree into the in-memory inode
3071  */
3072 static int btrfs_read_locked_inode(struct inode *inode,
3073                                    struct btrfs_path *in_path)
3074 {
3075         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3076         struct btrfs_path *path = in_path;
3077         struct extent_buffer *leaf;
3078         struct btrfs_inode_item *inode_item;
3079         struct btrfs_root *root = BTRFS_I(inode)->root;
3080         struct btrfs_key location;
3081         unsigned long ptr;
3082         int maybe_acls;
3083         u32 rdev;
3084         int ret;
3085         bool filled = false;
3086         int first_xattr_slot;
3087
3088         ret = btrfs_fill_inode(inode, &rdev);
3089         if (!ret)
3090                 filled = true;
3091
3092         if (!path) {
3093                 path = btrfs_alloc_path();
3094                 if (!path)
3095                         return -ENOMEM;
3096         }
3097
3098         memcpy(&location, &BTRFS_I(inode)->location, sizeof(location));
3099
3100         ret = btrfs_lookup_inode(NULL, root, path, &location, 0);
3101         if (ret) {
3102                 if (path != in_path)
3103                         btrfs_free_path(path);
3104                 return ret;
3105         }
3106
3107         leaf = path->nodes[0];
3108
3109         if (filled)
3110                 goto cache_index;
3111
3112         inode_item = btrfs_item_ptr(leaf, path->slots[0],
3113                                     struct btrfs_inode_item);
3114         inode->i_mode = btrfs_inode_mode(leaf, inode_item);
3115         set_nlink(inode, btrfs_inode_nlink(leaf, inode_item));
3116         i_uid_write(inode, btrfs_inode_uid(leaf, inode_item));
3117         i_gid_write(inode, btrfs_inode_gid(leaf, inode_item));
3118         btrfs_i_size_write(BTRFS_I(inode), btrfs_inode_size(leaf, inode_item));
3119
3120         inode->i_atime.tv_sec = btrfs_timespec_sec(leaf, &inode_item->atime);
3121         inode->i_atime.tv_nsec = btrfs_timespec_nsec(leaf, &inode_item->atime);
3122
3123         inode->i_mtime.tv_sec = btrfs_timespec_sec(leaf, &inode_item->mtime);
3124         inode->i_mtime.tv_nsec = btrfs_timespec_nsec(leaf, &inode_item->mtime);
3125
3126         inode->i_ctime.tv_sec = btrfs_timespec_sec(leaf, &inode_item->ctime);
3127         inode->i_ctime.tv_nsec = btrfs_timespec_nsec(leaf, &inode_item->ctime);
3128
3129         BTRFS_I(inode)->i_otime.tv_sec =
3130                 btrfs_timespec_sec(leaf, &inode_item->otime);
3131         BTRFS_I(inode)->i_otime.tv_nsec =
3132                 btrfs_timespec_nsec(leaf, &inode_item->otime);
3133
3134         inode_set_bytes(inode, btrfs_inode_nbytes(leaf, inode_item));
3135         BTRFS_I(inode)->generation = btrfs_inode_generation(leaf, inode_item);
3136         BTRFS_I(inode)->last_trans = btrfs_inode_transid(leaf, inode_item);
3137
3138         inode_set_iversion_queried(inode,
3139                                    btrfs_inode_sequence(leaf, inode_item));
3140         inode->i_generation = BTRFS_I(inode)->generation;
3141         inode->i_rdev = 0;
3142         rdev = btrfs_inode_rdev(leaf, inode_item);
3143
3144         BTRFS_I(inode)->index_cnt = (u64)-1;
3145         BTRFS_I(inode)->flags = btrfs_inode_flags(leaf, inode_item);
3146
3147 cache_index:
3148         /*
3149          * If we were modified in the current generation and evicted from memory
3150          * and then re-read we need to do a full sync since we don't have any
3151          * idea about which extents were modified before we were evicted from
3152          * cache.
3153          *
3154          * This is required for both inode re-read from disk and delayed inode
3155          * in delayed_nodes_tree.
3156          */
3157         if (BTRFS_I(inode)->last_trans == fs_info->generation)
3158                 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
3159                         &BTRFS_I(inode)->runtime_flags);
3160
3161         /*
3162          * We don't persist the id of the transaction where an unlink operation
3163          * against the inode was last made. So here we assume the inode might
3164          * have been evicted, and therefore the exact value of last_unlink_trans
3165          * lost, and set it to last_trans to avoid metadata inconsistencies
3166          * between the inode and its parent if the inode is fsync'ed and the log
3167          * replayed. For example, in the scenario:
3168          *
3169          * touch mydir/foo
3170          * ln mydir/foo mydir/bar
3171          * sync
3172          * unlink mydir/bar
3173          * echo 2 > /proc/sys/vm/drop_caches   # evicts inode
3174          * xfs_io -c fsync mydir/foo
3175          * <power failure>
3176          * mount fs, triggers fsync log replay
3177          *
3178          * We must make sure that when we fsync our inode foo we also log its
3179          * parent inode, otherwise after log replay the parent still has the
3180          * dentry with the "bar" name but our inode foo has a link count of 1
3181          * and doesn't have an inode ref with the name "bar" anymore.
3182          *
3183          * Setting last_unlink_trans to last_trans is a pessimistic approach,
3184          * but it guarantees correctness at the expense of occasional full
3185          * transaction commits on fsync if our inode is a directory, or if our
3186          * inode is not a directory, logging its parent unnecessarily.
3187          */
3188         BTRFS_I(inode)->last_unlink_trans = BTRFS_I(inode)->last_trans;
3189
3190         path->slots[0]++;
3191         if (inode->i_nlink != 1 ||
3192             path->slots[0] >= btrfs_header_nritems(leaf))
3193                 goto cache_acl;
3194
3195         btrfs_item_key_to_cpu(leaf, &location, path->slots[0]);
3196         if (location.objectid != btrfs_ino(BTRFS_I(inode)))
3197                 goto cache_acl;
3198
3199         ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
3200         if (location.type == BTRFS_INODE_REF_KEY) {
3201                 struct btrfs_inode_ref *ref;
3202
3203                 ref = (struct btrfs_inode_ref *)ptr;
3204                 BTRFS_I(inode)->dir_index = btrfs_inode_ref_index(leaf, ref);
3205         } else if (location.type == BTRFS_INODE_EXTREF_KEY) {
3206                 struct btrfs_inode_extref *extref;
3207
3208                 extref = (struct btrfs_inode_extref *)ptr;
3209                 BTRFS_I(inode)->dir_index = btrfs_inode_extref_index(leaf,
3210                                                                      extref);
3211         }
3212 cache_acl:
3213         /*
3214          * try to precache a NULL acl entry for files that don't have
3215          * any xattrs or acls
3216          */
3217         maybe_acls = acls_after_inode_item(leaf, path->slots[0],
3218                         btrfs_ino(BTRFS_I(inode)), &first_xattr_slot);
3219         if (first_xattr_slot != -1) {
3220                 path->slots[0] = first_xattr_slot;
3221                 ret = btrfs_load_inode_props(inode, path);
3222                 if (ret)
3223                         btrfs_err(fs_info,
3224                                   "error loading props for ino %llu (root %llu): %d",
3225                                   btrfs_ino(BTRFS_I(inode)),
3226                                   root->root_key.objectid, ret);
3227         }
3228         if (path != in_path)
3229                 btrfs_free_path(path);
3230
3231         if (!maybe_acls)
3232                 cache_no_acl(inode);
3233
3234         switch (inode->i_mode & S_IFMT) {
3235         case S_IFREG:
3236                 inode->i_mapping->a_ops = &btrfs_aops;
3237                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
3238                 inode->i_fop = &btrfs_file_operations;
3239                 inode->i_op = &btrfs_file_inode_operations;
3240                 break;
3241         case S_IFDIR:
3242                 inode->i_fop = &btrfs_dir_file_operations;
3243                 inode->i_op = &btrfs_dir_inode_operations;
3244                 break;
3245         case S_IFLNK:
3246                 inode->i_op = &btrfs_symlink_inode_operations;
3247                 inode_nohighmem(inode);
3248                 inode->i_mapping->a_ops = &btrfs_aops;
3249                 break;
3250         default:
3251                 inode->i_op = &btrfs_special_inode_operations;
3252                 init_special_inode(inode, inode->i_mode, rdev);
3253                 break;
3254         }
3255
3256         btrfs_sync_inode_flags_to_i_flags(inode);
3257         return 0;
3258 }
3259
3260 /*
3261  * given a leaf and an inode, copy the inode fields into the leaf
3262  */
3263 static void fill_inode_item(struct btrfs_trans_handle *trans,
3264                             struct extent_buffer *leaf,
3265                             struct btrfs_inode_item *item,
3266                             struct inode *inode)
3267 {
3268         struct btrfs_map_token token;
3269
3270         btrfs_init_map_token(&token, leaf);
3271
3272         btrfs_set_token_inode_uid(leaf, item, i_uid_read(inode), &token);
3273         btrfs_set_token_inode_gid(leaf, item, i_gid_read(inode), &token);
3274         btrfs_set_token_inode_size(leaf, item, BTRFS_I(inode)->disk_i_size,
3275                                    &token);
3276         btrfs_set_token_inode_mode(leaf, item, inode->i_mode, &token);
3277         btrfs_set_token_inode_nlink(leaf, item, inode->i_nlink, &token);
3278
3279         btrfs_set_token_timespec_sec(leaf, &item->atime,
3280                                      inode->i_atime.tv_sec, &token);
3281         btrfs_set_token_timespec_nsec(leaf, &item->atime,
3282                                       inode->i_atime.tv_nsec, &token);
3283
3284         btrfs_set_token_timespec_sec(leaf, &item->mtime,
3285                                      inode->i_mtime.tv_sec, &token);
3286         btrfs_set_token_timespec_nsec(leaf, &item->mtime,
3287                                       inode->i_mtime.tv_nsec, &token);
3288
3289         btrfs_set_token_timespec_sec(leaf, &item->ctime,
3290                                      inode->i_ctime.tv_sec, &token);
3291         btrfs_set_token_timespec_nsec(leaf, &item->ctime,
3292                                       inode->i_ctime.tv_nsec, &token);
3293
3294         btrfs_set_token_timespec_sec(leaf, &item->otime,
3295                                      BTRFS_I(inode)->i_otime.tv_sec, &token);
3296         btrfs_set_token_timespec_nsec(leaf, &item->otime,
3297                                       BTRFS_I(inode)->i_otime.tv_nsec, &token);
3298
3299         btrfs_set_token_inode_nbytes(leaf, item, inode_get_bytes(inode),
3300                                      &token);
3301         btrfs_set_token_inode_generation(leaf, item, BTRFS_I(inode)->generation,
3302                                          &token);
3303         btrfs_set_token_inode_sequence(leaf, item, inode_peek_iversion(inode),
3304                                        &token);
3305         btrfs_set_token_inode_transid(leaf, item, trans->transid, &token);
3306         btrfs_set_token_inode_rdev(leaf, item, inode->i_rdev, &token);
3307         btrfs_set_token_inode_flags(leaf, item, BTRFS_I(inode)->flags, &token);
3308         btrfs_set_token_inode_block_group(leaf, item, 0, &token);
3309 }
3310
3311 /*
3312  * copy everything in the in-memory inode into the btree.
3313  */
3314 static noinline int btrfs_update_inode_item(struct btrfs_trans_handle *trans,
3315                                 struct btrfs_root *root, struct inode *inode)
3316 {
3317         struct btrfs_inode_item *inode_item;
3318         struct btrfs_path *path;
3319         struct extent_buffer *leaf;
3320         int ret;
3321
3322         path = btrfs_alloc_path();
3323         if (!path)
3324                 return -ENOMEM;
3325
3326         path->leave_spinning = 1;
3327         ret = btrfs_lookup_inode(trans, root, path, &BTRFS_I(inode)->location,
3328                                  1);
3329         if (ret) {
3330                 if (ret > 0)
3331                         ret = -ENOENT;
3332                 goto failed;
3333         }
3334
3335         leaf = path->nodes[0];
3336         inode_item = btrfs_item_ptr(leaf, path->slots[0],
3337                                     struct btrfs_inode_item);
3338
3339         fill_inode_item(trans, leaf, inode_item, inode);
3340         btrfs_mark_buffer_dirty(leaf);
3341         btrfs_set_inode_last_trans(trans, inode);
3342         ret = 0;
3343 failed:
3344         btrfs_free_path(path);
3345         return ret;
3346 }
3347
3348 /*
3349  * copy everything in the in-memory inode into the btree.
3350  */
3351 noinline int btrfs_update_inode(struct btrfs_trans_handle *trans,
3352                                 struct btrfs_root *root, struct inode *inode)
3353 {
3354         struct btrfs_fs_info *fs_info = root->fs_info;
3355         int ret;
3356
3357         /*
3358          * If the inode is a free space inode, we can deadlock during commit
3359          * if we put it into the delayed code.
3360          *
3361          * The data relocation inode should also be directly updated
3362          * without delay
3363          */
3364         if (!btrfs_is_free_space_inode(BTRFS_I(inode))
3365             && root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID
3366             && !test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags)) {
3367                 btrfs_update_root_times(trans, root);
3368
3369                 ret = btrfs_delayed_update_inode(trans, root, inode);
3370                 if (!ret)
3371                         btrfs_set_inode_last_trans(trans, inode);
3372                 return ret;
3373         }
3374
3375         return btrfs_update_inode_item(trans, root, inode);
3376 }
3377
3378 noinline int btrfs_update_inode_fallback(struct btrfs_trans_handle *trans,
3379                                          struct btrfs_root *root,
3380                                          struct inode *inode)
3381 {
3382         int ret;
3383
3384         ret = btrfs_update_inode(trans, root, inode);
3385         if (ret == -ENOSPC)
3386                 return btrfs_update_inode_item(trans, root, inode);
3387         return ret;
3388 }
3389
3390 /*
3391  * unlink helper that gets used here in inode.c and in the tree logging
3392  * recovery code.  It remove a link in a directory with a given name, and
3393  * also drops the back refs in the inode to the directory
3394  */
3395 static int __btrfs_unlink_inode(struct btrfs_trans_handle *trans,
3396                                 struct btrfs_root *root,
3397                                 struct btrfs_inode *dir,
3398                                 struct btrfs_inode *inode,
3399                                 const char *name, int name_len)
3400 {
3401         struct btrfs_fs_info *fs_info = root->fs_info;
3402         struct btrfs_path *path;
3403         int ret = 0;
3404         struct btrfs_dir_item *di;
3405         u64 index;
3406         u64 ino = btrfs_ino(inode);
3407         u64 dir_ino = btrfs_ino(dir);
3408
3409         path = btrfs_alloc_path();
3410         if (!path) {
3411                 ret = -ENOMEM;
3412                 goto out;
3413         }
3414
3415         path->leave_spinning = 1;
3416         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
3417                                     name, name_len, -1);
3418         if (IS_ERR_OR_NULL(di)) {
3419                 ret = di ? PTR_ERR(di) : -ENOENT;
3420                 goto err;
3421         }
3422         ret = btrfs_delete_one_dir_name(trans, root, path, di);
3423         if (ret)
3424                 goto err;
3425         btrfs_release_path(path);
3426
3427         /*
3428          * If we don't have dir index, we have to get it by looking up
3429          * the inode ref, since we get the inode ref, remove it directly,
3430          * it is unnecessary to do delayed deletion.
3431          *
3432          * But if we have dir index, needn't search inode ref to get it.
3433          * Since the inode ref is close to the inode item, it is better
3434          * that we delay to delete it, and just do this deletion when
3435          * we update the inode item.
3436          */
3437         if (inode->dir_index) {
3438                 ret = btrfs_delayed_delete_inode_ref(inode);
3439                 if (!ret) {
3440                         index = inode->dir_index;
3441                         goto skip_backref;
3442                 }
3443         }
3444
3445         ret = btrfs_del_inode_ref(trans, root, name, name_len, ino,
3446                                   dir_ino, &index);
3447         if (ret) {
3448                 btrfs_info(fs_info,
3449                         "failed to delete reference to %.*s, inode %llu parent %llu",
3450                         name_len, name, ino, dir_ino);
3451                 btrfs_abort_transaction(trans, ret);
3452                 goto err;
3453         }
3454 skip_backref:
3455         ret = btrfs_delete_delayed_dir_index(trans, dir, index);
3456         if (ret) {
3457                 btrfs_abort_transaction(trans, ret);
3458                 goto err;
3459         }
3460
3461         ret = btrfs_del_inode_ref_in_log(trans, root, name, name_len, inode,
3462                         dir_ino);
3463         if (ret != 0 && ret != -ENOENT) {
3464                 btrfs_abort_transaction(trans, ret);
3465                 goto err;
3466         }
3467
3468         ret = btrfs_del_dir_entries_in_log(trans, root, name, name_len, dir,
3469                         index);
3470         if (ret == -ENOENT)
3471                 ret = 0;
3472         else if (ret)
3473                 btrfs_abort_transaction(trans, ret);
3474
3475         /*
3476          * If we have a pending delayed iput we could end up with the final iput
3477          * being run in btrfs-cleaner context.  If we have enough of these built
3478          * up we can end up burning a lot of time in btrfs-cleaner without any
3479          * way to throttle the unlinks.  Since we're currently holding a ref on
3480          * the inode we can run the delayed iput here without any issues as the
3481          * final iput won't be done until after we drop the ref we're currently
3482          * holding.
3483          */
3484         btrfs_run_delayed_iput(fs_info, inode);
3485 err:
3486         btrfs_free_path(path);
3487         if (ret)
3488                 goto out;
3489
3490         btrfs_i_size_write(dir, dir->vfs_inode.i_size - name_len * 2);
3491         inode_inc_iversion(&inode->vfs_inode);
3492         inode_inc_iversion(&dir->vfs_inode);
3493         inode->vfs_inode.i_ctime = dir->vfs_inode.i_mtime =
3494                 dir->vfs_inode.i_ctime = current_time(&inode->vfs_inode);
3495         ret = btrfs_update_inode(trans, root, &dir->vfs_inode);
3496 out:
3497         return ret;
3498 }
3499
3500 int btrfs_unlink_inode(struct btrfs_trans_handle *trans,
3501                        struct btrfs_root *root,
3502                        struct btrfs_inode *dir, struct btrfs_inode *inode,
3503                        const char *name, int name_len)
3504 {
3505         int ret;
3506         ret = __btrfs_unlink_inode(trans, root, dir, inode, name, name_len);
3507         if (!ret) {
3508                 drop_nlink(&inode->vfs_inode);
3509                 ret = btrfs_update_inode(trans, root, &inode->vfs_inode);
3510         }
3511         return ret;
3512 }
3513
3514 /*
3515  * helper to start transaction for unlink and rmdir.
3516  *
3517  * unlink and rmdir are special in btrfs, they do not always free space, so
3518  * if we cannot make our reservations the normal way try and see if there is
3519  * plenty of slack room in the global reserve to migrate, otherwise we cannot
3520  * allow the unlink to occur.
3521  */
3522 static struct btrfs_trans_handle *__unlink_start_trans(struct inode *dir)
3523 {
3524         struct btrfs_root *root = BTRFS_I(dir)->root;
3525
3526         /*
3527          * 1 for the possible orphan item
3528          * 1 for the dir item
3529          * 1 for the dir index
3530          * 1 for the inode ref
3531          * 1 for the inode
3532          */
3533         return btrfs_start_transaction_fallback_global_rsv(root, 5, 5);
3534 }
3535
3536 static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
3537 {
3538         struct btrfs_root *root = BTRFS_I(dir)->root;
3539         struct btrfs_trans_handle *trans;
3540         struct inode *inode = d_inode(dentry);
3541         int ret;
3542
3543         trans = __unlink_start_trans(dir);
3544         if (IS_ERR(trans))
3545                 return PTR_ERR(trans);
3546
3547         btrfs_record_unlink_dir(trans, BTRFS_I(dir), BTRFS_I(d_inode(dentry)),
3548                         0);
3549
3550         ret = btrfs_unlink_inode(trans, root, BTRFS_I(dir),
3551                         BTRFS_I(d_inode(dentry)), dentry->d_name.name,
3552                         dentry->d_name.len);
3553         if (ret)
3554                 goto out;
3555
3556         if (inode->i_nlink == 0) {
3557                 ret = btrfs_orphan_add(trans, BTRFS_I(inode));
3558                 if (ret)
3559                         goto out;
3560         }
3561
3562 out:
3563         btrfs_end_transaction(trans);
3564         btrfs_btree_balance_dirty(root->fs_info);
3565         return ret;
3566 }
3567
3568 static int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
3569                                struct inode *dir, struct dentry *dentry)
3570 {
3571         struct btrfs_root *root = BTRFS_I(dir)->root;
3572         struct btrfs_inode *inode = BTRFS_I(d_inode(dentry));
3573         struct btrfs_path *path;
3574         struct extent_buffer *leaf;
3575         struct btrfs_dir_item *di;
3576         struct btrfs_key key;
3577         const char *name = dentry->d_name.name;
3578         int name_len = dentry->d_name.len;
3579         u64 index;
3580         int ret;
3581         u64 objectid;
3582         u64 dir_ino = btrfs_ino(BTRFS_I(dir));
3583
3584         if (btrfs_ino(inode) == BTRFS_FIRST_FREE_OBJECTID) {
3585                 objectid = inode->root->root_key.objectid;
3586         } else if (btrfs_ino(inode) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID) {
3587                 objectid = inode->location.objectid;
3588         } else {
3589                 WARN_ON(1);
3590                 return -EINVAL;
3591         }
3592
3593         path = btrfs_alloc_path();
3594         if (!path)
3595                 return -ENOMEM;
3596
3597         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
3598                                    name, name_len, -1);
3599         if (IS_ERR_OR_NULL(di)) {
3600                 ret = di ? PTR_ERR(di) : -ENOENT;
3601                 goto out;
3602         }
3603
3604         leaf = path->nodes[0];
3605         btrfs_dir_item_key_to_cpu(leaf, di, &key);
3606         WARN_ON(key.type != BTRFS_ROOT_ITEM_KEY || key.objectid != objectid);
3607         ret = btrfs_delete_one_dir_name(trans, root, path, di);
3608         if (ret) {
3609                 btrfs_abort_transaction(trans, ret);
3610                 goto out;
3611         }
3612         btrfs_release_path(path);
3613
3614         /*
3615          * This is a placeholder inode for a subvolume we didn't have a
3616          * reference to at the time of the snapshot creation.  In the meantime
3617          * we could have renamed the real subvol link into our snapshot, so
3618          * depending on btrfs_del_root_ref to return -ENOENT here is incorret.
3619          * Instead simply lookup the dir_index_item for this entry so we can
3620          * remove it.  Otherwise we know we have a ref to the root and we can
3621          * call btrfs_del_root_ref, and it _shouldn't_ fail.
3622          */
3623         if (btrfs_ino(inode) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID) {
3624                 di = btrfs_search_dir_index_item(root, path, dir_ino,
3625                                                  name, name_len);
3626                 if (IS_ERR_OR_NULL(di)) {
3627                         if (!di)
3628                                 ret = -ENOENT;
3629                         else
3630                                 ret = PTR_ERR(di);
3631                         btrfs_abort_transaction(trans, ret);
3632                         goto out;
3633                 }
3634
3635                 leaf = path->nodes[0];
3636                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3637                 index = key.offset;
3638                 btrfs_release_path(path);
3639         } else {
3640                 ret = btrfs_del_root_ref(trans, objectid,
3641                                          root->root_key.objectid, dir_ino,
3642                                          &index, name, name_len);
3643                 if (ret) {
3644                         btrfs_abort_transaction(trans, ret);
3645                         goto out;
3646                 }
3647         }
3648
3649         ret = btrfs_delete_delayed_dir_index(trans, BTRFS_I(dir), index);
3650         if (ret) {
3651                 btrfs_abort_transaction(trans, ret);
3652                 goto out;
3653         }
3654
3655         btrfs_i_size_write(BTRFS_I(dir), dir->i_size - name_len * 2);
3656         inode_inc_iversion(dir);
3657         dir->i_mtime = dir->i_ctime = current_time(dir);
3658         ret = btrfs_update_inode_fallback(trans, root, dir);
3659         if (ret)
3660                 btrfs_abort_transaction(trans, ret);
3661 out:
3662         btrfs_free_path(path);
3663         return ret;
3664 }
3665
3666 /*
3667  * Helper to check if the subvolume references other subvolumes or if it's
3668  * default.
3669  */
3670 static noinline int may_destroy_subvol(struct btrfs_root *root)
3671 {
3672         struct btrfs_fs_info *fs_info = root->fs_info;
3673         struct btrfs_path *path;
3674         struct btrfs_dir_item *di;
3675         struct btrfs_key key;
3676         u64 dir_id;
3677         int ret;
3678
3679         path = btrfs_alloc_path();
3680         if (!path)
3681                 return -ENOMEM;
3682
3683         /* Make sure this root isn't set as the default subvol */
3684         dir_id = btrfs_super_root_dir(fs_info->super_copy);
3685         di = btrfs_lookup_dir_item(NULL, fs_info->tree_root, path,
3686                                    dir_id, "default", 7, 0);
3687         if (di && !IS_ERR(di)) {
3688                 btrfs_dir_item_key_to_cpu(path->nodes[0], di, &key);
3689                 if (key.objectid == root->root_key.objectid) {
3690                         ret = -EPERM;
3691                         btrfs_err(fs_info,
3692                                   "deleting default subvolume %llu is not allowed",
3693                                   key.objectid);
3694                         goto out;
3695                 }
3696                 btrfs_release_path(path);
3697         }
3698
3699         key.objectid = root->root_key.objectid;
3700         key.type = BTRFS_ROOT_REF_KEY;
3701         key.offset = (u64)-1;
3702
3703         ret = btrfs_search_slot(NULL, fs_info->tree_root, &key, path, 0, 0);
3704         if (ret < 0)
3705                 goto out;
3706         BUG_ON(ret == 0);
3707
3708         ret = 0;
3709         if (path->slots[0] > 0) {
3710                 path->slots[0]--;
3711                 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
3712                 if (key.objectid == root->root_key.objectid &&
3713                     key.type == BTRFS_ROOT_REF_KEY)
3714                         ret = -ENOTEMPTY;
3715         }
3716 out:
3717         btrfs_free_path(path);
3718         return ret;
3719 }
3720
3721 /* Delete all dentries for inodes belonging to the root */
3722 static void btrfs_prune_dentries(struct btrfs_root *root)
3723 {
3724         struct btrfs_fs_info *fs_info = root->fs_info;
3725         struct rb_node *node;
3726         struct rb_node *prev;
3727         struct btrfs_inode *entry;
3728         struct inode *inode;
3729         u64 objectid = 0;
3730
3731         if (!test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
3732                 WARN_ON(btrfs_root_refs(&root->root_item) != 0);
3733
3734         spin_lock(&root->inode_lock);
3735 again:
3736         node = root->inode_tree.rb_node;
3737         prev = NULL;
3738         while (node) {
3739                 prev = node;
3740                 entry = rb_entry(node, struct btrfs_inode, rb_node);
3741
3742                 if (objectid < btrfs_ino(entry))
3743                         node = node->rb_left;
3744                 else if (objectid > btrfs_ino(entry))
3745                         node = node->rb_right;
3746                 else
3747                         break;
3748         }
3749         if (!node) {
3750                 while (prev) {
3751                         entry = rb_entry(prev, struct btrfs_inode, rb_node);
3752                         if (objectid <= btrfs_ino(entry)) {
3753                                 node = prev;
3754                                 break;
3755                         }
3756                         prev = rb_next(prev);
3757                 }
3758         }
3759         while (node) {
3760                 entry = rb_entry(node, struct btrfs_inode, rb_node);
3761                 objectid = btrfs_ino(entry) + 1;
3762                 inode = igrab(&entry->vfs_inode);
3763                 if (inode) {
3764                         spin_unlock(&root->inode_lock);
3765                         if (atomic_read(&inode->i_count) > 1)
3766                                 d_prune_aliases(inode);
3767                         /*
3768                          * btrfs_drop_inode will have it removed from the inode
3769                          * cache when its usage count hits zero.
3770                          */
3771                         iput(inode);
3772                         cond_resched();
3773                         spin_lock(&root->inode_lock);
3774                         goto again;
3775                 }
3776
3777                 if (cond_resched_lock(&root->inode_lock))
3778                         goto again;
3779
3780                 node = rb_next(node);
3781         }
3782         spin_unlock(&root->inode_lock);
3783 }
3784
3785 int btrfs_delete_subvolume(struct inode *dir, struct dentry *dentry)
3786 {
3787         struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
3788         struct btrfs_root *root = BTRFS_I(dir)->root;
3789         struct inode *inode = d_inode(dentry);
3790         struct btrfs_root *dest = BTRFS_I(inode)->root;
3791         struct btrfs_trans_handle *trans;
3792         struct btrfs_block_rsv block_rsv;
3793         u64 root_flags;
3794         int ret;
3795         int err;
3796
3797         /*
3798          * Don't allow to delete a subvolume with send in progress. This is
3799          * inside the inode lock so the error handling that has to drop the bit
3800          * again is not run concurrently.
3801          */
3802         spin_lock(&dest->root_item_lock);
3803         if (dest->send_in_progress) {
3804                 spin_unlock(&dest->root_item_lock);
3805                 btrfs_warn(fs_info,
3806                            "attempt to delete subvolume %llu during send",
3807                            dest->root_key.objectid);
3808                 return -EPERM;
3809         }
3810         root_flags = btrfs_root_flags(&dest->root_item);
3811         btrfs_set_root_flags(&dest->root_item,
3812                              root_flags | BTRFS_ROOT_SUBVOL_DEAD);
3813         spin_unlock(&dest->root_item_lock);
3814
3815         down_write(&fs_info->subvol_sem);
3816
3817         err = may_destroy_subvol(dest);
3818         if (err)
3819                 goto out_up_write;
3820
3821         btrfs_init_block_rsv(&block_rsv, BTRFS_BLOCK_RSV_TEMP);
3822         /*
3823          * One for dir inode,
3824          * two for dir entries,
3825          * two for root ref/backref.
3826          */
3827         err = btrfs_subvolume_reserve_metadata(root, &block_rsv, 5, true);
3828         if (err)
3829                 goto out_up_write;
3830
3831         trans = btrfs_start_transaction(root, 0);
3832         if (IS_ERR(trans)) {
3833                 err = PTR_ERR(trans);
3834                 goto out_release;
3835         }
3836         trans->block_rsv = &block_rsv;
3837         trans->bytes_reserved = block_rsv.size;
3838
3839         btrfs_record_snapshot_destroy(trans, BTRFS_I(dir));
3840
3841         ret = btrfs_unlink_subvol(trans, dir, dentry);
3842         if (ret) {
3843                 err = ret;
3844                 btrfs_abort_transaction(trans, ret);
3845                 goto out_end_trans;
3846         }
3847
3848         btrfs_record_root_in_trans(trans, dest);
3849
3850         memset(&dest->root_item.drop_progress, 0,
3851                 sizeof(dest->root_item.drop_progress));
3852         dest->root_item.drop_level = 0;
3853         btrfs_set_root_refs(&dest->root_item, 0);
3854
3855         if (!test_and_set_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &dest->state)) {
3856                 ret = btrfs_insert_orphan_item(trans,
3857                                         fs_info->tree_root,
3858                                         dest->root_key.objectid);
3859                 if (ret) {
3860                         btrfs_abort_transaction(trans, ret);
3861                         err = ret;
3862                         goto out_end_trans;
3863                 }
3864         }
3865
3866         ret = btrfs_uuid_tree_remove(trans, dest->root_item.uuid,
3867                                   BTRFS_UUID_KEY_SUBVOL,
3868                                   dest->root_key.objectid);
3869         if (ret && ret != -ENOENT) {
3870                 btrfs_abort_transaction(trans, ret);
3871                 err = ret;
3872                 goto out_end_trans;
3873         }
3874         if (!btrfs_is_empty_uuid(dest->root_item.received_uuid)) {
3875                 ret = btrfs_uuid_tree_remove(trans,
3876                                           dest->root_item.received_uuid,
3877                                           BTRFS_UUID_KEY_RECEIVED_SUBVOL,
3878                                           dest->root_key.objectid);
3879                 if (ret && ret != -ENOENT) {
3880                         btrfs_abort_transaction(trans, ret);
3881                         err = ret;
3882                         goto out_end_trans;
3883                 }
3884         }
3885
3886 out_end_trans:
3887         trans->block_rsv = NULL;
3888         trans->bytes_reserved = 0;
3889         ret = btrfs_end_transaction(trans);
3890         if (ret && !err)
3891                 err = ret;
3892         inode->i_flags |= S_DEAD;
3893 out_release:
3894         btrfs_subvolume_release_metadata(fs_info, &block_rsv);
3895 out_up_write:
3896         up_write(&fs_info->subvol_sem);
3897         if (err) {
3898                 spin_lock(&dest->root_item_lock);
3899                 root_flags = btrfs_root_flags(&dest->root_item);
3900                 btrfs_set_root_flags(&dest->root_item,
3901                                 root_flags & ~BTRFS_ROOT_SUBVOL_DEAD);
3902                 spin_unlock(&dest->root_item_lock);
3903         } else {
3904                 d_invalidate(dentry);
3905                 btrfs_prune_dentries(dest);
3906                 ASSERT(dest->send_in_progress == 0);
3907
3908                 /* the last ref */
3909                 if (dest->ino_cache_inode) {
3910                         iput(dest->ino_cache_inode);
3911                         dest->ino_cache_inode = NULL;
3912                 }
3913         }
3914
3915         return err;
3916 }
3917
3918 static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
3919 {
3920         struct inode *inode = d_inode(dentry);
3921         int err = 0;
3922         struct btrfs_root *root = BTRFS_I(dir)->root;
3923         struct btrfs_trans_handle *trans;
3924         u64 last_unlink_trans;
3925
3926         if (inode->i_size > BTRFS_EMPTY_DIR_SIZE)
3927                 return -ENOTEMPTY;
3928         if (btrfs_ino(BTRFS_I(inode)) == BTRFS_FIRST_FREE_OBJECTID)
3929                 return btrfs_delete_subvolume(dir, dentry);
3930
3931         trans = __unlink_start_trans(dir);
3932         if (IS_ERR(trans))
3933                 return PTR_ERR(trans);
3934
3935         if (unlikely(btrfs_ino(BTRFS_I(inode)) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
3936                 err = btrfs_unlink_subvol(trans, dir, dentry);
3937                 goto out;
3938         }
3939
3940         err = btrfs_orphan_add(trans, BTRFS_I(inode));
3941         if (err)
3942                 goto out;
3943
3944         last_unlink_trans = BTRFS_I(inode)->last_unlink_trans;
3945
3946         /* now the directory is empty */
3947         err = btrfs_unlink_inode(trans, root, BTRFS_I(dir),
3948                         BTRFS_I(d_inode(dentry)), dentry->d_name.name,
3949                         dentry->d_name.len);
3950         if (!err) {
3951                 btrfs_i_size_write(BTRFS_I(inode), 0);
3952                 /*
3953                  * Propagate the last_unlink_trans value of the deleted dir to
3954                  * its parent directory. This is to prevent an unrecoverable
3955                  * log tree in the case we do something like this:
3956                  * 1) create dir foo
3957                  * 2) create snapshot under dir foo
3958                  * 3) delete the snapshot
3959                  * 4) rmdir foo
3960                  * 5) mkdir foo
3961                  * 6) fsync foo or some file inside foo
3962                  */
3963                 if (last_unlink_trans >= trans->transid)
3964                         BTRFS_I(dir)->last_unlink_trans = last_unlink_trans;
3965         }
3966 out:
3967         btrfs_end_transaction(trans);
3968         btrfs_btree_balance_dirty(root->fs_info);
3969
3970         return err;
3971 }
3972
3973 /*
3974  * Return this if we need to call truncate_block for the last bit of the
3975  * truncate.
3976  */
3977 #define NEED_TRUNCATE_BLOCK 1
3978
3979 /*
3980  * this can truncate away extent items, csum items and directory items.
3981  * It starts at a high offset and removes keys until it can't find
3982  * any higher than new_size
3983  *
3984  * csum items that cross the new i_size are truncated to the new size
3985  * as well.
3986  *
3987  * min_type is the minimum key type to truncate down to.  If set to 0, this
3988  * will kill all the items on this inode, including the INODE_ITEM_KEY.
3989  */
3990 int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
3991                                struct btrfs_root *root,
3992                                struct inode *inode,
3993                                u64 new_size, u32 min_type)
3994 {
3995         struct btrfs_fs_info *fs_info = root->fs_info;
3996         struct btrfs_path *path;
3997         struct extent_buffer *leaf;
3998         struct btrfs_file_extent_item *fi;
3999         struct btrfs_key key;
4000         struct btrfs_key found_key;
4001         u64 extent_start = 0;
4002         u64 extent_num_bytes = 0;
4003         u64 extent_offset = 0;
4004         u64 item_end = 0;
4005         u64 last_size = new_size;
4006         u32 found_type = (u8)-1;
4007         int found_extent;
4008         int del_item;
4009         int pending_del_nr = 0;
4010         int pending_del_slot = 0;
4011         int extent_type = -1;
4012         int ret;
4013         u64 ino = btrfs_ino(BTRFS_I(inode));
4014         u64 bytes_deleted = 0;
4015         bool be_nice = false;
4016         bool should_throttle = false;
4017
4018         BUG_ON(new_size > 0 && min_type != BTRFS_EXTENT_DATA_KEY);
4019
4020         /*
4021          * for non-free space inodes and ref cows, we want to back off from
4022          * time to time
4023          */
4024         if (!btrfs_is_free_space_inode(BTRFS_I(inode)) &&
4025             test_bit(BTRFS_ROOT_REF_COWS, &root->state))
4026                 be_nice = true;
4027
4028         path = btrfs_alloc_path();
4029         if (!path)
4030                 return -ENOMEM;
4031         path->reada = READA_BACK;
4032
4033         /*
4034          * We want to drop from the next block forward in case this new size is
4035          * not block aligned since we will be keeping the last block of the
4036          * extent just the way it is.
4037          */
4038         if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
4039             root == fs_info->tree_root)
4040                 btrfs_drop_extent_cache(BTRFS_I(inode), ALIGN(new_size,
4041                                         fs_info->sectorsize),
4042                                         (u64)-1, 0);
4043
4044         /*
4045          * This function is also used to drop the items in the log tree before
4046          * we relog the inode, so if root != BTRFS_I(inode)->root, it means
4047          * it is used to drop the logged items. So we shouldn't kill the delayed
4048          * items.
4049          */
4050         if (min_type == 0 && root == BTRFS_I(inode)->root)
4051                 btrfs_kill_delayed_inode_items(BTRFS_I(inode));
4052
4053         key.objectid = ino;
4054         key.offset = (u64)-1;
4055         key.type = (u8)-1;
4056
4057 search_again:
4058         /*
4059          * with a 16K leaf size and 128MB extents, you can actually queue
4060          * up a huge file in a single leaf.  Most of the time that
4061          * bytes_deleted is > 0, it will be huge by the time we get here
4062          */
4063         if (be_nice && bytes_deleted > SZ_32M &&
4064             btrfs_should_end_transaction(trans)) {
4065                 ret = -EAGAIN;
4066                 goto out;
4067         }
4068
4069         path->leave_spinning = 1;
4070         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
4071         if (ret < 0)
4072                 goto out;
4073
4074         if (ret > 0) {
4075                 ret = 0;
4076                 /* there are no items in the tree for us to truncate, we're
4077                  * done
4078                  */
4079                 if (path->slots[0] == 0)
4080                         goto out;
4081                 path->slots[0]--;
4082         }
4083
4084         while (1) {
4085                 fi = NULL;
4086                 leaf = path->nodes[0];
4087                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
4088                 found_type = found_key.type;
4089
4090                 if (found_key.objectid != ino)
4091                         break;
4092
4093                 if (found_type < min_type)
4094                         break;
4095
4096                 item_end = found_key.offset;
4097                 if (found_type == BTRFS_EXTENT_DATA_KEY) {
4098                         fi = btrfs_item_ptr(leaf, path->slots[0],
4099                                             struct btrfs_file_extent_item);
4100                         extent_type = btrfs_file_extent_type(leaf, fi);
4101                         if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
4102                                 item_end +=
4103                                     btrfs_file_extent_num_bytes(leaf, fi);
4104
4105                                 trace_btrfs_truncate_show_fi_regular(
4106                                         BTRFS_I(inode), leaf, fi,
4107                                         found_key.offset);
4108                         } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
4109                                 item_end += btrfs_file_extent_ram_bytes(leaf,
4110                                                                         fi);
4111
4112                                 trace_btrfs_truncate_show_fi_inline(
4113                                         BTRFS_I(inode), leaf, fi, path->slots[0],
4114                                         found_key.offset);
4115                         }
4116                         item_end--;
4117                 }
4118                 if (found_type > min_type) {
4119                         del_item = 1;
4120                 } else {
4121                         if (item_end < new_size)
4122                                 break;
4123                         if (found_key.offset >= new_size)
4124                                 del_item = 1;
4125                         else
4126                                 del_item = 0;
4127                 }
4128                 found_extent = 0;
4129                 /* FIXME, shrink the extent if the ref count is only 1 */
4130                 if (found_type != BTRFS_EXTENT_DATA_KEY)
4131                         goto delete;
4132
4133                 if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
4134                         u64 num_dec;
4135                         extent_start = btrfs_file_extent_disk_bytenr(leaf, fi);
4136                         if (!del_item) {
4137                                 u64 orig_num_bytes =
4138                                         btrfs_file_extent_num_bytes(leaf, fi);
4139                                 extent_num_bytes = ALIGN(new_size -
4140                                                 found_key.offset,
4141                                                 fs_info->sectorsize);
4142                                 btrfs_set_file_extent_num_bytes(leaf, fi,
4143                                                          extent_num_bytes);
4144                                 num_dec = (orig_num_bytes -
4145                                            extent_num_bytes);
4146                                 if (test_bit(BTRFS_ROOT_REF_COWS,
4147                                              &root->state) &&
4148                                     extent_start != 0)
4149                                         inode_sub_bytes(inode, num_dec);
4150                                 btrfs_mark_buffer_dirty(leaf);
4151                         } else {
4152                                 extent_num_bytes =
4153                                         btrfs_file_extent_disk_num_bytes(leaf,
4154                                                                          fi);
4155                                 extent_offset = found_key.offset -
4156                                         btrfs_file_extent_offset(leaf, fi);
4157
4158                                 /* FIXME blocksize != 4096 */
4159                                 num_dec = btrfs_file_extent_num_bytes(leaf, fi);
4160                                 if (extent_start != 0) {
4161                                         found_extent = 1;
4162                                         if (test_bit(BTRFS_ROOT_REF_COWS,
4163                                                      &root->state))
4164                                                 inode_sub_bytes(inode, num_dec);
4165                                 }
4166                         }
4167                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
4168                         /*
4169                          * we can't truncate inline items that have had
4170                          * special encodings
4171                          */
4172                         if (!del_item &&
4173                             btrfs_file_extent_encryption(leaf, fi) == 0 &&
4174                             btrfs_file_extent_other_encoding(leaf, fi) == 0 &&
4175                             btrfs_file_extent_compression(leaf, fi) == 0) {
4176                                 u32 size = (u32)(new_size - found_key.offset);
4177
4178                                 btrfs_set_file_extent_ram_bytes(leaf, fi, size);
4179                                 size = btrfs_file_extent_calc_inline_size(size);
4180                                 btrfs_truncate_item(path, size, 1);
4181                         } else if (!del_item) {
4182                                 /*
4183                                  * We have to bail so the last_size is set to
4184                                  * just before this extent.
4185                                  */
4186                                 ret = NEED_TRUNCATE_BLOCK;
4187                                 break;
4188                         }
4189
4190                         if (test_bit(BTRFS_ROOT_REF_COWS, &root->state))
4191                                 inode_sub_bytes(inode, item_end + 1 - new_size);
4192                 }
4193 delete:
4194                 if (del_item)
4195                         last_size = found_key.offset;
4196                 else
4197                         last_size = new_size;
4198                 if (del_item) {
4199                         if (!pending_del_nr) {
4200                                 /* no pending yet, add ourselves */
4201                                 pending_del_slot = path->slots[0];
4202                                 pending_del_nr = 1;
4203                         } else if (pending_del_nr &&
4204                                    path->slots[0] + 1 == pending_del_slot) {
4205                                 /* hop on the pending chunk */
4206                                 pending_del_nr++;
4207                                 pending_del_slot = path->slots[0];
4208                         } else {
4209                                 BUG();
4210                         }
4211                 } else {
4212                         break;
4213                 }
4214                 should_throttle = false;
4215
4216                 if (found_extent &&
4217                     (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
4218                      root == fs_info->tree_root)) {
4219                         struct btrfs_ref ref = { 0 };
4220
4221                         btrfs_set_path_blocking(path);
4222                         bytes_deleted += extent_num_bytes;
4223
4224                         btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF,
4225                                         extent_start, extent_num_bytes, 0);
4226                         ref.real_root = root->root_key.objectid;
4227                         btrfs_init_data_ref(&ref, btrfs_header_owner(leaf),
4228                                         ino, extent_offset);
4229                         ret = btrfs_free_extent(trans, &ref);
4230                         if (ret) {
4231                                 btrfs_abort_transaction(trans, ret);
4232                                 break;
4233                         }
4234                         if (be_nice) {
4235                                 if (btrfs_should_throttle_delayed_refs(trans))
4236                                         should_throttle = true;
4237                         }
4238                 }
4239
4240                 if (found_type == BTRFS_INODE_ITEM_KEY)
4241                         break;
4242
4243                 if (path->slots[0] == 0 ||
4244                     path->slots[0] != pending_del_slot ||
4245                     should_throttle) {
4246                         if (pending_del_nr) {
4247                                 ret = btrfs_del_items(trans, root, path,
4248                                                 pending_del_slot,
4249                                                 pending_del_nr);
4250                                 if (ret) {
4251                                         btrfs_abort_transaction(trans, ret);
4252                                         break;
4253                                 }
4254                                 pending_del_nr = 0;
4255                         }
4256                         btrfs_release_path(path);
4257
4258                         /*
4259                          * We can generate a lot of delayed refs, so we need to
4260                          * throttle every once and a while and make sure we're
4261                          * adding enough space to keep up with the work we are
4262                          * generating.  Since we hold a transaction here we
4263                          * can't flush, and we don't want to FLUSH_LIMIT because
4264                          * we could have generated too many delayed refs to
4265                          * actually allocate, so just bail if we're short and
4266                          * let the normal reservation dance happen higher up.
4267                          */
4268                         if (should_throttle) {
4269                                 ret = btrfs_delayed_refs_rsv_refill(fs_info,
4270                                                         BTRFS_RESERVE_NO_FLUSH);
4271                                 if (ret) {
4272                                         ret = -EAGAIN;
4273                                         break;
4274                                 }
4275                         }
4276                         goto search_again;
4277                 } else {
4278                         path->slots[0]--;
4279                 }
4280         }
4281 out:
4282         if (ret >= 0 && pending_del_nr) {
4283                 int err;
4284
4285                 err = btrfs_del_items(trans, root, path, pending_del_slot,
4286                                       pending_del_nr);
4287                 if (err) {
4288                         btrfs_abort_transaction(trans, err);
4289                         ret = err;
4290                 }
4291         }
4292         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
4293                 ASSERT(last_size >= new_size);
4294                 if (!ret && last_size > new_size)
4295                         last_size = new_size;
4296                 btrfs_ordered_update_i_size(inode, last_size, NULL);
4297         }
4298
4299         btrfs_free_path(path);
4300         return ret;
4301 }
4302
4303 /*
4304  * btrfs_truncate_block - read, zero a chunk and write a block
4305  * @inode - inode that we're zeroing
4306  * @from - the offset to start zeroing
4307  * @len - the length to zero, 0 to zero the entire range respective to the
4308  *      offset
4309  * @front - zero up to the offset instead of from the offset on
4310  *
4311  * This will find the block for the "from" offset and cow the block and zero the
4312  * part we want to zero.  This is used with truncate and hole punching.
4313  */
4314 int btrfs_truncate_block(struct inode *inode, loff_t from, loff_t len,
4315                         int front)
4316 {
4317         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4318         struct address_space *mapping = inode->i_mapping;
4319         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4320         struct btrfs_ordered_extent *ordered;
4321         struct extent_state *cached_state = NULL;
4322         struct extent_changeset *data_reserved = NULL;
4323         char *kaddr;
4324         u32 blocksize = fs_info->sectorsize;
4325         pgoff_t index = from >> PAGE_SHIFT;
4326         unsigned offset = from & (blocksize - 1);
4327         struct page *page;
4328         gfp_t mask = btrfs_alloc_write_mask(mapping);
4329         int ret = 0;
4330         u64 block_start;
4331         u64 block_end;
4332
4333         if (IS_ALIGNED(offset, blocksize) &&
4334             (!len || IS_ALIGNED(len, blocksize)))
4335                 goto out;
4336
4337         block_start = round_down(from, blocksize);
4338         block_end = block_start + blocksize - 1;
4339
4340         ret = btrfs_delalloc_reserve_space(inode, &data_reserved,
4341                                            block_start, blocksize);
4342         if (ret)
4343                 goto out;
4344
4345 again:
4346         page = find_or_create_page(mapping, index, mask);
4347         if (!page) {
4348                 btrfs_delalloc_release_space(inode, data_reserved,
4349                                              block_start, blocksize, true);
4350                 btrfs_delalloc_release_extents(BTRFS_I(inode), blocksize);
4351                 ret = -ENOMEM;
4352                 goto out;
4353         }
4354
4355         if (!PageUptodate(page)) {
4356                 ret = btrfs_readpage(NULL, page);
4357                 lock_page(page);
4358                 if (page->mapping != mapping) {
4359                         unlock_page(page);
4360                         put_page(page);
4361                         goto again;
4362                 }
4363                 if (!PageUptodate(page)) {
4364                         ret = -EIO;
4365                         goto out_unlock;
4366                 }
4367         }
4368         wait_on_page_writeback(page);
4369
4370         lock_extent_bits(io_tree, block_start, block_end, &cached_state);
4371         set_page_extent_mapped(page);
4372
4373         ordered = btrfs_lookup_ordered_extent(inode, block_start);
4374         if (ordered) {
4375                 unlock_extent_cached(io_tree, block_start, block_end,
4376                                      &cached_state);
4377                 unlock_page(page);
4378                 put_page(page);
4379                 btrfs_start_ordered_extent(inode, ordered, 1);
4380                 btrfs_put_ordered_extent(ordered);
4381                 goto again;
4382         }
4383
4384         clear_extent_bit(&BTRFS_I(inode)->io_tree, block_start, block_end,
4385                          EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
4386                          0, 0, &cached_state);
4387
4388         ret = btrfs_set_extent_delalloc(inode, block_start, block_end, 0,
4389                                         &cached_state);
4390         if (ret) {
4391                 unlock_extent_cached(io_tree, block_start, block_end,
4392                                      &cached_state);
4393                 goto out_unlock;
4394         }
4395
4396         if (offset != blocksize) {
4397                 if (!len)
4398                         len = blocksize - offset;
4399                 kaddr = kmap(page);
4400                 if (front)
4401                         memset(kaddr + (block_start - page_offset(page)),
4402                                 0, offset);
4403                 else
4404                         memset(kaddr + (block_start - page_offset(page)) +  offset,
4405                                 0, len);
4406                 flush_dcache_page(page);
4407                 kunmap(page);
4408         }
4409         ClearPageChecked(page);
4410         set_page_dirty(page);
4411         unlock_extent_cached(io_tree, block_start, block_end, &cached_state);
4412
4413 out_unlock:
4414         if (ret)
4415                 btrfs_delalloc_release_space(inode, data_reserved, block_start,
4416                                              blocksize, true);
4417         btrfs_delalloc_release_extents(BTRFS_I(inode), blocksize);
4418         unlock_page(page);
4419         put_page(page);
4420 out:
4421         extent_changeset_free(data_reserved);
4422         return ret;
4423 }
4424
4425 static int maybe_insert_hole(struct btrfs_root *root, struct inode *inode,
4426                              u64 offset, u64 len)
4427 {
4428         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4429         struct btrfs_trans_handle *trans;
4430         int ret;
4431
4432         /*
4433          * Still need to make sure the inode looks like it's been updated so
4434          * that any holes get logged if we fsync.
4435          */
4436         if (btrfs_fs_incompat(fs_info, NO_HOLES)) {
4437                 BTRFS_I(inode)->last_trans = fs_info->generation;
4438                 BTRFS_I(inode)->last_sub_trans = root->log_transid;
4439                 BTRFS_I(inode)->last_log_commit = root->last_log_commit;
4440                 return 0;
4441         }
4442
4443         /*
4444          * 1 - for the one we're dropping
4445          * 1 - for the one we're adding
4446          * 1 - for updating the inode.
4447          */
4448         trans = btrfs_start_transaction(root, 3);
4449         if (IS_ERR(trans))
4450                 return PTR_ERR(trans);
4451
4452         ret = btrfs_drop_extents(trans, root, inode, offset, offset + len, 1);
4453         if (ret) {
4454                 btrfs_abort_transaction(trans, ret);
4455                 btrfs_end_transaction(trans);
4456                 return ret;
4457         }
4458
4459         ret = btrfs_insert_file_extent(trans, root, btrfs_ino(BTRFS_I(inode)),
4460                         offset, 0, 0, len, 0, len, 0, 0, 0);
4461         if (ret)
4462                 btrfs_abort_transaction(trans, ret);
4463         else
4464                 btrfs_update_inode(trans, root, inode);
4465         btrfs_end_transaction(trans);
4466         return ret;
4467 }
4468
4469 /*
4470  * This function puts in dummy file extents for the area we're creating a hole
4471  * for.  So if we are truncating this file to a larger size we need to insert
4472  * these file extents so that btrfs_get_extent will return a EXTENT_MAP_HOLE for
4473  * the range between oldsize and size
4474  */
4475 int btrfs_cont_expand(struct inode *inode, loff_t oldsize, loff_t size)
4476 {
4477         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4478         struct btrfs_root *root = BTRFS_I(inode)->root;
4479         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4480         struct extent_map *em = NULL;
4481         struct extent_state *cached_state = NULL;
4482         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
4483         u64 hole_start = ALIGN(oldsize, fs_info->sectorsize);
4484         u64 block_end = ALIGN(size, fs_info->sectorsize);
4485         u64 last_byte;
4486         u64 cur_offset;
4487         u64 hole_size;
4488         int err = 0;
4489
4490         /*
4491          * If our size started in the middle of a block we need to zero out the
4492          * rest of the block before we expand the i_size, otherwise we could
4493          * expose stale data.
4494          */
4495         err = btrfs_truncate_block(inode, oldsize, 0, 0);
4496         if (err)
4497                 return err;
4498
4499         if (size <= hole_start)
4500                 return 0;
4501
4502         btrfs_lock_and_flush_ordered_range(io_tree, BTRFS_I(inode), hole_start,
4503                                            block_end - 1, &cached_state);
4504         cur_offset = hole_start;
4505         while (1) {
4506                 em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, cur_offset,
4507                                       block_end - cur_offset);
4508                 if (IS_ERR(em)) {
4509                         err = PTR_ERR(em);
4510                         em = NULL;
4511                         break;
4512                 }
4513                 last_byte = min(extent_map_end(em), block_end);
4514                 last_byte = ALIGN(last_byte, fs_info->sectorsize);
4515                 if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
4516                         struct extent_map *hole_em;
4517                         hole_size = last_byte - cur_offset;
4518
4519                         err = maybe_insert_hole(root, inode, cur_offset,
4520                                                 hole_size);
4521                         if (err)
4522                                 break;
4523                         btrfs_drop_extent_cache(BTRFS_I(inode), cur_offset,
4524                                                 cur_offset + hole_size - 1, 0);
4525                         hole_em = alloc_extent_map();
4526                         if (!hole_em) {
4527                                 set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
4528                                         &BTRFS_I(inode)->runtime_flags);
4529                                 goto next;
4530                         }
4531                         hole_em->start = cur_offset;
4532                         hole_em->len = hole_size;
4533                         hole_em->orig_start = cur_offset;
4534
4535                         hole_em->block_start = EXTENT_MAP_HOLE;
4536                         hole_em->block_len = 0;
4537                         hole_em->orig_block_len = 0;
4538                         hole_em->ram_bytes = hole_size;
4539                         hole_em->compress_type = BTRFS_COMPRESS_NONE;
4540                         hole_em->generation = fs_info->generation;
4541
4542                         while (1) {
4543                                 write_lock(&em_tree->lock);
4544                                 err = add_extent_mapping(em_tree, hole_em, 1);
4545                                 write_unlock(&em_tree->lock);
4546                                 if (err != -EEXIST)
4547                                         break;
4548                                 btrfs_drop_extent_cache(BTRFS_I(inode),
4549                                                         cur_offset,
4550                                                         cur_offset +
4551                                                         hole_size - 1, 0);
4552                         }
4553                         free_extent_map(hole_em);
4554                 }
4555 next:
4556                 free_extent_map(em);
4557                 em = NULL;
4558                 cur_offset = last_byte;
4559                 if (cur_offset >= block_end)
4560                         break;
4561         }
4562         free_extent_map(em);
4563         unlock_extent_cached(io_tree, hole_start, block_end - 1, &cached_state);
4564         return err;
4565 }
4566
4567 static int btrfs_setsize(struct inode *inode, struct iattr *attr)
4568 {
4569         struct btrfs_root *root = BTRFS_I(inode)->root;
4570         struct btrfs_trans_handle *trans;
4571         loff_t oldsize = i_size_read(inode);
4572         loff_t newsize = attr->ia_size;
4573         int mask = attr->ia_valid;
4574         int ret;
4575
4576         /*
4577          * The regular truncate() case without ATTR_CTIME and ATTR_MTIME is a
4578          * special case where we need to update the times despite not having
4579          * these flags set.  For all other operations the VFS set these flags
4580          * explicitly if it wants a timestamp update.
4581          */
4582         if (newsize != oldsize) {
4583                 inode_inc_iversion(inode);
4584                 if (!(mask & (ATTR_CTIME | ATTR_MTIME)))
4585                         inode->i_ctime = inode->i_mtime =
4586                                 current_time(inode);
4587         }
4588
4589         if (newsize > oldsize) {
4590                 /*
4591                  * Don't do an expanding truncate while snapshotting is ongoing.
4592                  * This is to ensure the snapshot captures a fully consistent
4593                  * state of this file - if the snapshot captures this expanding
4594                  * truncation, it must capture all writes that happened before
4595                  * this truncation.
4596                  */
4597                 btrfs_wait_for_snapshot_creation(root);
4598                 ret = btrfs_cont_expand(inode, oldsize, newsize);
4599                 if (ret) {
4600                         btrfs_end_write_no_snapshotting(root);
4601                         return ret;
4602                 }
4603
4604                 trans = btrfs_start_transaction(root, 1);
4605                 if (IS_ERR(trans)) {
4606                         btrfs_end_write_no_snapshotting(root);
4607                         return PTR_ERR(trans);
4608                 }
4609
4610                 i_size_write(inode, newsize);
4611                 btrfs_ordered_update_i_size(inode, i_size_read(inode), NULL);
4612                 pagecache_isize_extended(inode, oldsize, newsize);
4613                 ret = btrfs_update_inode(trans, root, inode);
4614                 btrfs_end_write_no_snapshotting(root);
4615                 btrfs_end_transaction(trans);
4616         } else {
4617
4618                 /*
4619                  * We're truncating a file that used to have good data down to
4620                  * zero. Make sure it gets into the ordered flush list so that
4621                  * any new writes get down to disk quickly.
4622                  */
4623                 if (newsize == 0)
4624                         set_bit(BTRFS_INODE_ORDERED_DATA_CLOSE,
4625                                 &BTRFS_I(inode)->runtime_flags);
4626
4627                 truncate_setsize(inode, newsize);
4628
4629                 /* Disable nonlocked read DIO to avoid the endless truncate */
4630                 btrfs_inode_block_unlocked_dio(BTRFS_I(inode));
4631                 inode_dio_wait(inode);
4632                 btrfs_inode_resume_unlocked_dio(BTRFS_I(inode));
4633
4634                 ret = btrfs_truncate(inode, newsize == oldsize);
4635                 if (ret && inode->i_nlink) {
4636                         int err;
4637
4638                         /*
4639                          * Truncate failed, so fix up the in-memory size. We
4640                          * adjusted disk_i_size down as we removed extents, so
4641                          * wait for disk_i_size to be stable and then update the
4642                          * in-memory size to match.
4643                          */
4644                         err = btrfs_wait_ordered_range(inode, 0, (u64)-1);
4645                         if (err)
4646                                 return err;
4647                         i_size_write(inode, BTRFS_I(inode)->disk_i_size);
4648                 }
4649         }
4650
4651         return ret;
4652 }
4653
4654 static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
4655 {
4656         struct inode *inode = d_inode(dentry);
4657         struct btrfs_root *root = BTRFS_I(inode)->root;
4658         int err;
4659
4660         if (btrfs_root_readonly(root))
4661                 return -EROFS;
4662
4663         err = setattr_prepare(dentry, attr);
4664         if (err)
4665                 return err;
4666
4667         if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {
4668                 err = btrfs_setsize(inode, attr);
4669                 if (err)
4670                         return err;
4671         }
4672
4673         if (attr->ia_valid) {
4674                 setattr_copy(inode, attr);
4675                 inode_inc_iversion(inode);
4676                 err = btrfs_dirty_inode(inode);
4677
4678                 if (!err && attr->ia_valid & ATTR_MODE)
4679                         err = posix_acl_chmod(inode, inode->i_mode);
4680         }
4681
4682         return err;
4683 }
4684
4685 /*
4686  * While truncating the inode pages during eviction, we get the VFS calling
4687  * btrfs_invalidatepage() against each page of the inode. This is slow because
4688  * the calls to btrfs_invalidatepage() result in a huge amount of calls to
4689  * lock_extent_bits() and clear_extent_bit(), which keep merging and splitting
4690  * extent_state structures over and over, wasting lots of time.
4691  *
4692  * Therefore if the inode is being evicted, let btrfs_invalidatepage() skip all
4693  * those expensive operations on a per page basis and do only the ordered io
4694  * finishing, while we release here the extent_map and extent_state structures,
4695  * without the excessive merging and splitting.
4696  */
4697 static void evict_inode_truncate_pages(struct inode *inode)
4698 {
4699         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4700         struct extent_map_tree *map_tree = &BTRFS_I(inode)->extent_tree;
4701         struct rb_node *node;
4702
4703         ASSERT(inode->i_state & I_FREEING);
4704         truncate_inode_pages_final(&inode->i_data);
4705
4706         write_lock(&map_tree->lock);
4707         while (!RB_EMPTY_ROOT(&map_tree->map.rb_root)) {
4708                 struct extent_map *em;
4709
4710                 node = rb_first_cached(&map_tree->map);
4711                 em = rb_entry(node, struct extent_map, rb_node);
4712                 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
4713                 clear_bit(EXTENT_FLAG_LOGGING, &em->flags);
4714                 remove_extent_mapping(map_tree, em);
4715                 free_extent_map(em);
4716                 if (need_resched()) {
4717                         write_unlock(&map_tree->lock);
4718                         cond_resched();
4719                         write_lock(&map_tree->lock);
4720                 }
4721         }
4722         write_unlock(&map_tree->lock);
4723
4724         /*
4725          * Keep looping until we have no more ranges in the io tree.
4726          * We can have ongoing bios started by readpages (called from readahead)
4727          * that have their endio callback (extent_io.c:end_bio_extent_readpage)
4728          * still in progress (unlocked the pages in the bio but did not yet
4729          * unlocked the ranges in the io tree). Therefore this means some
4730          * ranges can still be locked and eviction started because before
4731          * submitting those bios, which are executed by a separate task (work
4732          * queue kthread), inode references (inode->i_count) were not taken
4733          * (which would be dropped in the end io callback of each bio).
4734          * Therefore here we effectively end up waiting for those bios and
4735          * anyone else holding locked ranges without having bumped the inode's
4736          * reference count - if we don't do it, when they access the inode's
4737          * io_tree to unlock a range it may be too late, leading to an
4738          * use-after-free issue.
4739          */
4740         spin_lock(&io_tree->lock);
4741         while (!RB_EMPTY_ROOT(&io_tree->state)) {
4742                 struct extent_state *state;
4743                 struct extent_state *cached_state = NULL;
4744                 u64 start;
4745                 u64 end;
4746                 unsigned state_flags;
4747
4748                 node = rb_first(&io_tree->state);
4749                 state = rb_entry(node, struct extent_state, rb_node);
4750                 start = state->start;
4751                 end = state->end;
4752                 state_flags = state->state;
4753                 spin_unlock(&io_tree->lock);
4754
4755                 lock_extent_bits(io_tree, start, end, &cached_state);
4756
4757                 /*
4758                  * If still has DELALLOC flag, the extent didn't reach disk,
4759                  * and its reserved space won't be freed by delayed_ref.
4760                  * So we need to free its reserved space here.
4761                  * (Refer to comment in btrfs_invalidatepage, case 2)
4762                  *
4763                  * Note, end is the bytenr of last byte, so we need + 1 here.
4764                  */
4765                 if (state_flags & EXTENT_DELALLOC)
4766                         btrfs_qgroup_free_data(inode, NULL, start, end - start + 1);
4767
4768                 clear_extent_bit(io_tree, start, end,
4769                                  EXTENT_LOCKED | EXTENT_DELALLOC |
4770                                  EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG, 1, 1,
4771                                  &cached_state);
4772
4773                 cond_resched();
4774                 spin_lock(&io_tree->lock);
4775         }
4776         spin_unlock(&io_tree->lock);
4777 }
4778
4779 static struct btrfs_trans_handle *evict_refill_and_join(struct btrfs_root *root,
4780                                                         struct btrfs_block_rsv *rsv)
4781 {
4782         struct btrfs_fs_info *fs_info = root->fs_info;
4783         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
4784         struct btrfs_trans_handle *trans;
4785         u64 delayed_refs_extra = btrfs_calc_insert_metadata_size(fs_info, 1);
4786         int ret;
4787
4788         /*
4789          * Eviction should be taking place at some place safe because of our
4790          * delayed iputs.  However the normal flushing code will run delayed
4791          * iputs, so we cannot use FLUSH_ALL otherwise we'll deadlock.
4792          *
4793          * We reserve the delayed_refs_extra here again because we can't use
4794          * btrfs_start_transaction(root, 0) for the same deadlocky reason as
4795          * above.  We reserve our extra bit here because we generate a ton of
4796          * delayed refs activity by truncating.
4797          *
4798          * If we cannot make our reservation we'll attempt to steal from the
4799          * global reserve, because we really want to be able to free up space.
4800          */
4801         ret = btrfs_block_rsv_refill(root, rsv, rsv->size + delayed_refs_extra,
4802                                      BTRFS_RESERVE_FLUSH_EVICT);
4803         if (ret) {
4804                 /*
4805                  * Try to steal from the global reserve if there is space for
4806                  * it.
4807                  */
4808                 if (btrfs_check_space_for_delayed_refs(fs_info) ||
4809                     btrfs_block_rsv_migrate(global_rsv, rsv, rsv->size, 0)) {
4810                         btrfs_warn(fs_info,
4811                                    "could not allocate space for delete; will truncate on mount");
4812                         return ERR_PTR(-ENOSPC);
4813                 }
4814                 delayed_refs_extra = 0;
4815         }
4816
4817         trans = btrfs_join_transaction(root);
4818         if (IS_ERR(trans))
4819                 return trans;
4820
4821         if (delayed_refs_extra) {
4822                 trans->block_rsv = &fs_info->trans_block_rsv;
4823                 trans->bytes_reserved = delayed_refs_extra;
4824                 btrfs_block_rsv_migrate(rsv, trans->block_rsv,
4825                                         delayed_refs_extra, 1);
4826         }
4827         return trans;
4828 }
4829
4830 void btrfs_evict_inode(struct inode *inode)
4831 {
4832         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4833         struct btrfs_trans_handle *trans;
4834         struct btrfs_root *root = BTRFS_I(inode)->root;
4835         struct btrfs_block_rsv *rsv;
4836         int ret;
4837
4838         trace_btrfs_inode_evict(inode);
4839
4840         if (!root) {
4841                 clear_inode(inode);
4842                 return;
4843         }
4844
4845         evict_inode_truncate_pages(inode);
4846
4847         if (inode->i_nlink &&
4848             ((btrfs_root_refs(&root->root_item) != 0 &&
4849               root->root_key.objectid != BTRFS_ROOT_TREE_OBJECTID) ||
4850              btrfs_is_free_space_inode(BTRFS_I(inode))))
4851                 goto no_delete;
4852
4853         if (is_bad_inode(inode))
4854                 goto no_delete;
4855
4856         btrfs_free_io_failure_record(BTRFS_I(inode), 0, (u64)-1);
4857
4858         if (test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags))
4859                 goto no_delete;
4860
4861         if (inode->i_nlink > 0) {
4862                 BUG_ON(btrfs_root_refs(&root->root_item) != 0 &&
4863                        root->root_key.objectid != BTRFS_ROOT_TREE_OBJECTID);
4864                 goto no_delete;
4865         }
4866
4867         ret = btrfs_commit_inode_delayed_inode(BTRFS_I(inode));
4868         if (ret)
4869                 goto no_delete;
4870
4871         rsv = btrfs_alloc_block_rsv(fs_info, BTRFS_BLOCK_RSV_TEMP);
4872         if (!rsv)
4873                 goto no_delete;
4874         rsv->size = btrfs_calc_metadata_size(fs_info, 1);
4875         rsv->failfast = 1;
4876
4877         btrfs_i_size_write(BTRFS_I(inode), 0);
4878
4879         while (1) {
4880                 trans = evict_refill_and_join(root, rsv);
4881                 if (IS_ERR(trans))
4882                         goto free_rsv;
4883
4884                 trans->block_rsv = rsv;
4885
4886                 ret = btrfs_truncate_inode_items(trans, root, inode, 0, 0);
4887                 trans->block_rsv = &fs_info->trans_block_rsv;
4888                 btrfs_end_transaction(trans);
4889                 btrfs_btree_balance_dirty(fs_info);
4890                 if (ret && ret != -ENOSPC && ret != -EAGAIN)
4891                         goto free_rsv;
4892                 else if (!ret)
4893                         break;
4894         }
4895
4896         /*
4897          * Errors here aren't a big deal, it just means we leave orphan items in
4898          * the tree. They will be cleaned up on the next mount. If the inode
4899          * number gets reused, cleanup deletes the orphan item without doing
4900          * anything, and unlink reuses the existing orphan item.
4901          *
4902          * If it turns out that we are dropping too many of these, we might want
4903          * to add a mechanism for retrying these after a commit.
4904          */
4905         trans = evict_refill_and_join(root, rsv);
4906         if (!IS_ERR(trans)) {
4907                 trans->block_rsv = rsv;
4908                 btrfs_orphan_del(trans, BTRFS_I(inode));
4909                 trans->block_rsv = &fs_info->trans_block_rsv;
4910                 btrfs_end_transaction(trans);
4911         }
4912
4913         if (!(root == fs_info->tree_root ||
4914               root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID))
4915                 btrfs_return_ino(root, btrfs_ino(BTRFS_I(inode)));
4916
4917 free_rsv:
4918         btrfs_free_block_rsv(fs_info, rsv);
4919 no_delete:
4920         /*
4921          * If we didn't successfully delete, the orphan item will still be in
4922          * the tree and we'll retry on the next mount. Again, we might also want
4923          * to retry these periodically in the future.
4924          */
4925         btrfs_remove_delayed_node(BTRFS_I(inode));
4926         clear_inode(inode);
4927 }
4928
4929 /*
4930  * Return the key found in the dir entry in the location pointer, fill @type
4931  * with BTRFS_FT_*, and return 0.
4932  *
4933  * If no dir entries were found, returns -ENOENT.
4934  * If found a corrupted location in dir entry, returns -EUCLEAN.
4935  */
4936 static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
4937                                struct btrfs_key *location, u8 *type)
4938 {
4939         const char *name = dentry->d_name.name;
4940         int namelen = dentry->d_name.len;
4941         struct btrfs_dir_item *di;
4942         struct btrfs_path *path;
4943         struct btrfs_root *root = BTRFS_I(dir)->root;
4944         int ret = 0;
4945
4946         path = btrfs_alloc_path();
4947         if (!path)
4948                 return -ENOMEM;
4949
4950         di = btrfs_lookup_dir_item(NULL, root, path, btrfs_ino(BTRFS_I(dir)),
4951                         name, namelen, 0);
4952         if (IS_ERR_OR_NULL(di)) {
4953                 ret = di ? PTR_ERR(di) : -ENOENT;
4954                 goto out;
4955         }
4956
4957         btrfs_dir_item_key_to_cpu(path->nodes[0], di, location);
4958         if (location->type != BTRFS_INODE_ITEM_KEY &&
4959             location->type != BTRFS_ROOT_ITEM_KEY) {
4960                 ret = -EUCLEAN;
4961                 btrfs_warn(root->fs_info,
4962 "%s gets something invalid in DIR_ITEM (name %s, directory ino %llu, location(%llu %u %llu))",
4963                            __func__, name, btrfs_ino(BTRFS_I(dir)),
4964                            location->objectid, location->type, location->offset);
4965         }
4966         if (!ret)
4967                 *type = btrfs_dir_type(path->nodes[0], di);
4968 out:
4969         btrfs_free_path(path);
4970         return ret;
4971 }
4972
4973 /*
4974  * when we hit a tree root in a directory, the btrfs part of the inode
4975  * needs to be changed to reflect the root directory of the tree root.  This
4976  * is kind of like crossing a mount point.
4977  */
4978 static int fixup_tree_root_location(struct btrfs_fs_info *fs_info,
4979                                     struct inode *dir,
4980                                     struct dentry *dentry,
4981                                     struct btrfs_key *location,
4982                                     struct btrfs_root **sub_root)
4983 {
4984         struct btrfs_path *path;
4985         struct btrfs_root *new_root;
4986         struct btrfs_root_ref *ref;
4987         struct extent_buffer *leaf;
4988         struct btrfs_key key;
4989         int ret;
4990         int err = 0;
4991
4992         path = btrfs_alloc_path();
4993         if (!path) {
4994                 err = -ENOMEM;
4995                 goto out;
4996         }
4997
4998         err = -ENOENT;
4999         key.objectid = BTRFS_I(dir)->root->root_key.objectid;
5000         key.type = BTRFS_ROOT_REF_KEY;
5001         key.offset = location->objectid;
5002
5003         ret = btrfs_search_slot(NULL, fs_info->tree_root, &key, path, 0, 0);
5004         if (ret) {
5005                 if (ret < 0)
5006                         err = ret;
5007                 goto out;
5008         }
5009
5010         leaf = path->nodes[0];
5011         ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
5012         if (btrfs_root_ref_dirid(leaf, ref) != btrfs_ino(BTRFS_I(dir)) ||
5013             btrfs_root_ref_name_len(leaf, ref) != dentry->d_name.len)
5014                 goto out;
5015
5016         ret = memcmp_extent_buffer(leaf, dentry->d_name.name,
5017                                    (unsigned long)(ref + 1),
5018                                    dentry->d_name.len);
5019         if (ret)
5020                 goto out;
5021
5022         btrfs_release_path(path);
5023
5024         new_root = btrfs_read_fs_root_no_name(fs_info, location);
5025         if (IS_ERR(new_root)) {
5026                 err = PTR_ERR(new_root);
5027                 goto out;
5028         }
5029
5030         *sub_root = new_root;
5031         location->objectid = btrfs_root_dirid(&new_root->root_item);
5032         location->type = BTRFS_INODE_ITEM_KEY;
5033         location->offset = 0;
5034         err = 0;
5035 out:
5036         btrfs_free_path(path);
5037         return err;
5038 }
5039
5040 static void inode_tree_add(struct inode *inode)
5041 {
5042         struct btrfs_root *root = BTRFS_I(inode)->root;
5043         struct btrfs_inode *entry;
5044         struct rb_node **p;
5045         struct rb_node *parent;
5046         struct rb_node *new = &BTRFS_I(inode)->rb_node;
5047         u64 ino = btrfs_ino(BTRFS_I(inode));
5048
5049         if (inode_unhashed(inode))
5050                 return;
5051         parent = NULL;
5052         spin_lock(&root->inode_lock);
5053         p = &root->inode_tree.rb_node;
5054         while (*p) {
5055                 parent = *p;
5056                 entry = rb_entry(parent, struct btrfs_inode, rb_node);
5057
5058                 if (ino < btrfs_ino(entry))
5059                         p = &parent->rb_left;
5060                 else if (ino > btrfs_ino(entry))
5061                         p = &parent->rb_right;
5062                 else {
5063                         WARN_ON(!(entry->vfs_inode.i_state &
5064                                   (I_WILL_FREE | I_FREEING)));
5065                         rb_replace_node(parent, new, &root->inode_tree);
5066                         RB_CLEAR_NODE(parent);
5067                         spin_unlock(&root->inode_lock);
5068                         return;
5069                 }
5070         }
5071         rb_link_node(new, parent, p);
5072         rb_insert_color(new, &root->inode_tree);
5073         spin_unlock(&root->inode_lock);
5074 }
5075
5076 static void inode_tree_del(struct inode *inode)
5077 {
5078         struct btrfs_root *root = BTRFS_I(inode)->root;
5079         int empty = 0;
5080
5081         spin_lock(&root->inode_lock);
5082         if (!RB_EMPTY_NODE(&BTRFS_I(inode)->rb_node)) {
5083                 rb_erase(&BTRFS_I(inode)->rb_node, &root->inode_tree);
5084                 RB_CLEAR_NODE(&BTRFS_I(inode)->rb_node);
5085                 empty = RB_EMPTY_ROOT(&root->inode_tree);
5086         }
5087         spin_unlock(&root->inode_lock);
5088
5089         if (empty && btrfs_root_refs(&root->root_item) == 0) {
5090                 spin_lock(&root->inode_lock);
5091                 empty = RB_EMPTY_ROOT(&root->inode_tree);
5092                 spin_unlock(&root->inode_lock);
5093                 if (empty)
5094                         btrfs_add_dead_root(root);
5095         }
5096 }
5097
5098
5099 static int btrfs_init_locked_inode(struct inode *inode, void *p)
5100 {
5101         struct btrfs_iget_args *args = p;
5102         inode->i_ino = args->location->objectid;
5103         memcpy(&BTRFS_I(inode)->location, args->location,
5104                sizeof(*args->location));
5105         BTRFS_I(inode)->root = args->root;
5106         return 0;
5107 }
5108
5109 static int btrfs_find_actor(struct inode *inode, void *opaque)
5110 {
5111         struct btrfs_iget_args *args = opaque;
5112         return args->location->objectid == BTRFS_I(inode)->location.objectid &&
5113                 args->root == BTRFS_I(inode)->root;
5114 }
5115
5116 static struct inode *btrfs_iget_locked(struct super_block *s,
5117                                        struct btrfs_key *location,
5118                                        struct btrfs_root *root)
5119 {
5120         struct inode *inode;
5121         struct btrfs_iget_args args;
5122         unsigned long hashval = btrfs_inode_hash(location->objectid, root);
5123
5124         args.location = location;
5125         args.root = root;
5126
5127         inode = iget5_locked(s, hashval, btrfs_find_actor,
5128                              btrfs_init_locked_inode,
5129                              (void *)&args);
5130         return inode;
5131 }
5132
5133 /*
5134  * Get an inode object given its location and corresponding root.
5135  * Path can be preallocated to prevent recursing back to iget through
5136  * allocator. NULL is also valid but may require an additional allocation
5137  * later.
5138  */
5139 struct inode *btrfs_iget_path(struct super_block *s, struct btrfs_key *location,
5140                               struct btrfs_root *root, struct btrfs_path *path)
5141 {
5142         struct inode *inode;
5143
5144         inode = btrfs_iget_locked(s, location, root);
5145         if (!inode)
5146                 return ERR_PTR(-ENOMEM);
5147
5148         if (inode->i_state & I_NEW) {
5149                 int ret;
5150
5151                 ret = btrfs_read_locked_inode(inode, path);
5152                 if (!ret) {
5153                         inode_tree_add(inode);
5154                         unlock_new_inode(inode);
5155                 } else {
5156                         iget_failed(inode);
5157                         /*
5158                          * ret > 0 can come from btrfs_search_slot called by
5159                          * btrfs_read_locked_inode, this means the inode item
5160                          * was not found.
5161                          */
5162                         if (ret > 0)
5163                                 ret = -ENOENT;
5164                         inode = ERR_PTR(ret);
5165                 }
5166         }
5167
5168         return inode;
5169 }
5170
5171 struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location,
5172                          struct btrfs_root *root)
5173 {
5174         return btrfs_iget_path(s, location, root, NULL);
5175 }
5176
5177 static struct inode *new_simple_dir(struct super_block *s,
5178                                     struct btrfs_key *key,
5179                                     struct btrfs_root *root)
5180 {
5181         struct inode *inode = new_inode(s);
5182
5183         if (!inode)
5184                 return ERR_PTR(-ENOMEM);
5185
5186         BTRFS_I(inode)->root = root;
5187         memcpy(&BTRFS_I(inode)->location, key, sizeof(*key));
5188         set_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags);
5189
5190         inode->i_ino = BTRFS_EMPTY_SUBVOL_DIR_OBJECTID;
5191         /*
5192          * We only need lookup, the rest is read-only and there's no inode
5193          * associated with the dentry
5194          */
5195         inode->i_op = &simple_dir_inode_operations;
5196         inode->i_opflags &= ~IOP_XATTR;
5197         inode->i_fop = &simple_dir_operations;
5198         inode->i_mode = S_IFDIR | S_IRUGO | S_IWUSR | S_IXUGO;
5199         inode->i_mtime = current_time(inode);
5200         inode->i_atime = inode->i_mtime;
5201         inode->i_ctime = inode->i_mtime;
5202         BTRFS_I(inode)->i_otime = inode->i_mtime;
5203
5204         return inode;
5205 }
5206
5207 static inline u8 btrfs_inode_type(struct inode *inode)
5208 {
5209         /*
5210          * Compile-time asserts that generic FT_* types still match
5211          * BTRFS_FT_* types
5212          */
5213         BUILD_BUG_ON(BTRFS_FT_UNKNOWN != FT_UNKNOWN);
5214         BUILD_BUG_ON(BTRFS_FT_REG_FILE != FT_REG_FILE);
5215         BUILD_BUG_ON(BTRFS_FT_DIR != FT_DIR);
5216         BUILD_BUG_ON(BTRFS_FT_CHRDEV != FT_CHRDEV);
5217         BUILD_BUG_ON(BTRFS_FT_BLKDEV != FT_BLKDEV);
5218         BUILD_BUG_ON(BTRFS_FT_FIFO != FT_FIFO);
5219         BUILD_BUG_ON(BTRFS_FT_SOCK != FT_SOCK);
5220         BUILD_BUG_ON(BTRFS_FT_SYMLINK != FT_SYMLINK);
5221
5222         return fs_umode_to_ftype(inode->i_mode);
5223 }
5224
5225 struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry)
5226 {
5227         struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
5228         struct inode *inode;
5229         struct btrfs_root *root = BTRFS_I(dir)->root;
5230         struct btrfs_root *sub_root = root;
5231         struct btrfs_key location;
5232         u8 di_type = 0;
5233         int index;
5234         int ret = 0;
5235
5236         if (dentry->d_name.len > BTRFS_NAME_LEN)
5237                 return ERR_PTR(-ENAMETOOLONG);
5238
5239         ret = btrfs_inode_by_name(dir, dentry, &location, &di_type);
5240         if (ret < 0)
5241                 return ERR_PTR(ret);
5242
5243         if (location.type == BTRFS_INODE_ITEM_KEY) {
5244                 inode = btrfs_iget(dir->i_sb, &location, root);
5245                 if (IS_ERR(inode))
5246                         return inode;
5247
5248                 /* Do extra check against inode mode with di_type */
5249                 if (btrfs_inode_type(inode) != di_type) {
5250                         btrfs_crit(fs_info,
5251 "inode mode mismatch with dir: inode mode=0%o btrfs type=%u dir type=%u",
5252                                   inode->i_mode, btrfs_inode_type(inode),
5253                                   di_type);
5254                         iput(inode);
5255                         return ERR_PTR(-EUCLEAN);
5256                 }
5257                 return inode;
5258         }
5259
5260         index = srcu_read_lock(&fs_info->subvol_srcu);
5261         ret = fixup_tree_root_location(fs_info, dir, dentry,
5262                                        &location, &sub_root);
5263         if (ret < 0) {
5264                 if (ret != -ENOENT)
5265                         inode = ERR_PTR(ret);
5266                 else
5267                         inode = new_simple_dir(dir->i_sb, &location, sub_root);
5268         } else {
5269                 inode = btrfs_iget(dir->i_sb, &location, sub_root);
5270         }
5271         srcu_read_unlock(&fs_info->subvol_srcu, index);
5272
5273         if (!IS_ERR(inode) && root != sub_root) {
5274                 down_read(&fs_info->cleanup_work_sem);
5275                 if (!sb_rdonly(inode->i_sb))
5276                         ret = btrfs_orphan_cleanup(sub_root);
5277                 up_read(&fs_info->cleanup_work_sem);
5278                 if (ret) {
5279                         iput(inode);
5280                         inode = ERR_PTR(ret);
5281                 }
5282         }
5283
5284         return inode;
5285 }
5286
5287 static int btrfs_dentry_delete(const struct dentry *dentry)
5288 {
5289         struct btrfs_root *root;
5290         struct inode *inode = d_inode(dentry);
5291
5292         if (!inode && !IS_ROOT(dentry))
5293                 inode = d_inode(dentry->d_parent);
5294
5295         if (inode) {
5296                 root = BTRFS_I(inode)->root;
5297                 if (btrfs_root_refs(&root->root_item) == 0)
5298                         return 1;
5299
5300                 if (btrfs_ino(BTRFS_I(inode)) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
5301                         return 1;
5302         }
5303         return 0;
5304 }
5305
5306 static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
5307                                    unsigned int flags)
5308 {
5309         struct inode *inode = btrfs_lookup_dentry(dir, dentry);
5310
5311         if (inode == ERR_PTR(-ENOENT))
5312                 inode = NULL;
5313         return d_splice_alias(inode, dentry);
5314 }
5315
5316 /*
5317  * All this infrastructure exists because dir_emit can fault, and we are holding
5318  * the tree lock when doing readdir.  For now just allocate a buffer and copy
5319  * our information into that, and then dir_emit from the buffer.  This is
5320  * similar to what NFS does, only we don't keep the buffer around in pagecache
5321  * because I'm afraid I'll mess that up.  Long term we need to make filldir do
5322  * copy_to_user_inatomic so we don't have to worry about page faulting under the
5323  * tree lock.
5324  */
5325 static int btrfs_opendir(struct inode *inode, struct file *file)
5326 {
5327         struct btrfs_file_private *private;
5328
5329         private = kzalloc(sizeof(struct btrfs_file_private), GFP_KERNEL);
5330         if (!private)
5331                 return -ENOMEM;
5332         private->filldir_buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
5333         if (!private->filldir_buf) {
5334                 kfree(private);
5335                 return -ENOMEM;
5336         }
5337         file->private_data = private;
5338         return 0;
5339 }
5340
5341 struct dir_entry {
5342         u64 ino;
5343         u64 offset;
5344         unsigned type;
5345         int name_len;
5346 };
5347
5348 static int btrfs_filldir(void *addr, int entries, struct dir_context *ctx)
5349 {
5350         while (entries--) {
5351                 struct dir_entry *entry = addr;
5352                 char *name = (char *)(entry + 1);
5353
5354                 ctx->pos = get_unaligned(&entry->offset);
5355                 if (!dir_emit(ctx, name, get_unaligned(&entry->name_len),
5356                                          get_unaligned(&entry->ino),
5357                                          get_unaligned(&entry->type)))
5358                         return 1;
5359                 addr += sizeof(struct dir_entry) +
5360                         get_unaligned(&entry->name_len);
5361                 ctx->pos++;
5362         }
5363         return 0;
5364 }
5365
5366 static int btrfs_real_readdir(struct file *file, struct dir_context *ctx)
5367 {
5368         struct inode *inode = file_inode(file);
5369         struct btrfs_root *root = BTRFS_I(inode)->root;
5370         struct btrfs_file_private *private = file->private_data;
5371         struct btrfs_dir_item *di;
5372         struct btrfs_key key;
5373         struct btrfs_key found_key;
5374         struct btrfs_path *path;
5375         void *addr;
5376         struct list_head ins_list;
5377         struct list_head del_list;
5378         int ret;
5379         struct extent_buffer *leaf;
5380         int slot;
5381         char *name_ptr;
5382         int name_len;
5383         int entries = 0;
5384         int total_len = 0;
5385         bool put = false;
5386         struct btrfs_key location;
5387
5388         if (!dir_emit_dots(file, ctx))
5389                 return 0;
5390
5391         path = btrfs_alloc_path();
5392         if (!path)
5393                 return -ENOMEM;
5394
5395         addr = private->filldir_buf;
5396         path->reada = READA_FORWARD;
5397
5398         INIT_LIST_HEAD(&ins_list);
5399         INIT_LIST_HEAD(&del_list);
5400         put = btrfs_readdir_get_delayed_items(inode, &ins_list, &del_list);
5401
5402 again:
5403         key.type = BTRFS_DIR_INDEX_KEY;
5404         key.offset = ctx->pos;
5405         key.objectid = btrfs_ino(BTRFS_I(inode));
5406
5407         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5408         if (ret < 0)
5409                 goto err;
5410
5411         while (1) {
5412                 struct dir_entry *entry;
5413
5414                 leaf = path->nodes[0];
5415                 slot = path->slots[0];
5416                 if (slot >= btrfs_header_nritems(leaf)) {
5417                         ret = btrfs_next_leaf(root, path);
5418                         if (ret < 0)
5419                                 goto err;
5420                         else if (ret > 0)
5421                                 break;
5422                         continue;
5423                 }
5424
5425                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
5426
5427                 if (found_key.objectid != key.objectid)
5428                         break;
5429                 if (found_key.type != BTRFS_DIR_INDEX_KEY)
5430                         break;
5431                 if (found_key.offset < ctx->pos)
5432                         goto next;
5433                 if (btrfs_should_delete_dir_index(&del_list, found_key.offset))
5434                         goto next;
5435                 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
5436                 name_len = btrfs_dir_name_len(leaf, di);
5437                 if ((total_len + sizeof(struct dir_entry) + name_len) >=
5438                     PAGE_SIZE) {
5439                         btrfs_release_path(path);
5440                         ret = btrfs_filldir(private->filldir_buf, entries, ctx);
5441                         if (ret)
5442                                 goto nopos;
5443                         addr = private->filldir_buf;
5444                         entries = 0;
5445                         total_len = 0;
5446                         goto again;
5447                 }
5448
5449                 entry = addr;
5450                 put_unaligned(name_len, &entry->name_len);
5451                 name_ptr = (char *)(entry + 1);
5452                 read_extent_buffer(leaf, name_ptr, (unsigned long)(di + 1),
5453                                    name_len);
5454                 put_unaligned(fs_ftype_to_dtype(btrfs_dir_type(leaf, di)),
5455                                 &entry->type);
5456                 btrfs_dir_item_key_to_cpu(leaf, di, &location);
5457                 put_unaligned(location.objectid, &entry->ino);
5458                 put_unaligned(found_key.offset, &entry->offset);
5459                 entries++;
5460                 addr += sizeof(struct dir_entry) + name_len;
5461                 total_len += sizeof(struct dir_entry) + name_len;
5462 next:
5463                 path->slots[0]++;
5464         }
5465         btrfs_release_path(path);
5466
5467         ret = btrfs_filldir(private->filldir_buf, entries, ctx);
5468         if (ret)
5469                 goto nopos;
5470
5471         ret = btrfs_readdir_delayed_dir_index(ctx, &ins_list);
5472         if (ret)
5473                 goto nopos;
5474
5475         /*
5476          * Stop new entries from being returned after we return the last
5477          * entry.
5478          *
5479          * New directory entries are assigned a strictly increasing
5480          * offset.  This means that new entries created during readdir
5481          * are *guaranteed* to be seen in the future by that readdir.
5482          * This has broken buggy programs which operate on names as
5483          * they're returned by readdir.  Until we re-use freed offsets
5484          * we have this hack to stop new entries from being returned
5485          * under the assumption that they'll never reach this huge
5486          * offset.
5487          *
5488          * This is being careful not to overflow 32bit loff_t unless the
5489          * last entry requires it because doing so has broken 32bit apps
5490          * in the past.
5491          */
5492         if (ctx->pos >= INT_MAX)
5493                 ctx->pos = LLONG_MAX;
5494         else
5495                 ctx->pos = INT_MAX;
5496 nopos:
5497         ret = 0;
5498 err:
5499         if (put)
5500                 btrfs_readdir_put_delayed_items(inode, &ins_list, &del_list);
5501         btrfs_free_path(path);
5502         return ret;
5503 }
5504
5505 /*
5506  * This is somewhat expensive, updating the tree every time the
5507  * inode changes.  But, it is most likely to find the inode in cache.
5508  * FIXME, needs more benchmarking...there are no reasons other than performance
5509  * to keep or drop this code.
5510  */
5511 static int btrfs_dirty_inode(struct inode *inode)
5512 {
5513         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
5514         struct btrfs_root *root = BTRFS_I(inode)->root;
5515         struct btrfs_trans_handle *trans;
5516         int ret;
5517
5518         if (test_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags))
5519                 return 0;
5520
5521         trans = btrfs_join_transaction(root);
5522         if (IS_ERR(trans))
5523                 return PTR_ERR(trans);
5524
5525         ret = btrfs_update_inode(trans, root, inode);
5526         if (ret && ret == -ENOSPC) {
5527                 /* whoops, lets try again with the full transaction */
5528                 btrfs_end_transaction(trans);
5529                 trans = btrfs_start_transaction(root, 1);
5530                 if (IS_ERR(trans))
5531                         return PTR_ERR(trans);
5532
5533                 ret = btrfs_update_inode(trans, root, inode);
5534         }
5535         btrfs_end_transaction(trans);
5536         if (BTRFS_I(inode)->delayed_node)
5537                 btrfs_balance_delayed_items(fs_info);
5538
5539         return ret;
5540 }
5541
5542 /*
5543  * This is a copy of file_update_time.  We need this so we can return error on
5544  * ENOSPC for updating the inode in the case of file write and mmap writes.
5545  */
5546 static int btrfs_update_time(struct inode *inode, struct timespec64 *now,
5547                              int flags)
5548 {
5549         struct btrfs_root *root = BTRFS_I(inode)->root;
5550         bool dirty = flags & ~S_VERSION;
5551
5552         if (btrfs_root_readonly(root))
5553                 return -EROFS;
5554
5555         if (flags & S_VERSION)
5556                 dirty |= inode_maybe_inc_iversion(inode, dirty);
5557         if (flags & S_CTIME)
5558                 inode->i_ctime = *now;
5559         if (flags & S_MTIME)
5560                 inode->i_mtime = *now;
5561         if (flags & S_ATIME)
5562                 inode->i_atime = *now;
5563         return dirty ? btrfs_dirty_inode(inode) : 0;
5564 }
5565
5566 /*
5567  * find the highest existing sequence number in a directory
5568  * and then set the in-memory index_cnt variable to reflect
5569  * free sequence numbers
5570  */
5571 static int btrfs_set_inode_index_count(struct btrfs_inode *inode)
5572 {
5573         struct btrfs_root *root = inode->root;
5574         struct btrfs_key key, found_key;
5575         struct btrfs_path *path;
5576         struct extent_buffer *leaf;
5577         int ret;
5578
5579         key.objectid = btrfs_ino(inode);
5580         key.type = BTRFS_DIR_INDEX_KEY;
5581         key.offset = (u64)-1;
5582
5583         path = btrfs_alloc_path();
5584         if (!path)
5585                 return -ENOMEM;
5586
5587         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5588         if (ret < 0)
5589                 goto out;
5590         /* FIXME: we should be able to handle this */
5591         if (ret == 0)
5592                 goto out;
5593         ret = 0;
5594
5595         /*
5596          * MAGIC NUMBER EXPLANATION:
5597          * since we search a directory based on f_pos we have to start at 2
5598          * since '.' and '..' have f_pos of 0 and 1 respectively, so everybody
5599          * else has to start at 2
5600          */
5601         if (path->slots[0] == 0) {
5602                 inode->index_cnt = 2;
5603                 goto out;
5604         }
5605
5606         path->slots[0]--;
5607
5608         leaf = path->nodes[0];
5609         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
5610
5611         if (found_key.objectid != btrfs_ino(inode) ||
5612             found_key.type != BTRFS_DIR_INDEX_KEY) {
5613                 inode->index_cnt = 2;
5614                 goto out;
5615         }
5616
5617         inode->index_cnt = found_key.offset + 1;
5618 out:
5619         btrfs_free_path(path);
5620         return ret;
5621 }
5622
5623 /*
5624  * helper to find a free sequence number in a given directory.  This current
5625  * code is very simple, later versions will do smarter things in the btree
5626  */
5627 int btrfs_set_inode_index(struct btrfs_inode *dir, u64 *index)
5628 {
5629         int ret = 0;
5630
5631         if (dir->index_cnt == (u64)-1) {
5632                 ret = btrfs_inode_delayed_dir_index_count(dir);
5633                 if (ret) {
5634                         ret = btrfs_set_inode_index_count(dir);
5635                         if (ret)
5636                                 return ret;
5637                 }
5638         }
5639
5640         *index = dir->index_cnt;
5641         dir->index_cnt++;
5642
5643         return ret;
5644 }
5645
5646 static int btrfs_insert_inode_locked(struct inode *inode)
5647 {
5648         struct btrfs_iget_args args;
5649         args.location = &BTRFS_I(inode)->location;
5650         args.root = BTRFS_I(inode)->root;
5651
5652         return insert_inode_locked4(inode,
5653                    btrfs_inode_hash(inode->i_ino, BTRFS_I(inode)->root),
5654                    btrfs_find_actor, &args);
5655 }
5656
5657 /*
5658  * Inherit flags from the parent inode.
5659  *
5660  * Currently only the compression flags and the cow flags are inherited.
5661  */
5662 static void btrfs_inherit_iflags(struct inode *inode, struct inode *dir)
5663 {
5664         unsigned int flags;
5665
5666         if (!dir)
5667                 return;
5668
5669         flags = BTRFS_I(dir)->flags;
5670
5671         if (flags & BTRFS_INODE_NOCOMPRESS) {
5672                 BTRFS_I(inode)->flags &= ~BTRFS_INODE_COMPRESS;
5673                 BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
5674         } else if (flags & BTRFS_INODE_COMPRESS) {
5675                 BTRFS_I(inode)->flags &= ~BTRFS_INODE_NOCOMPRESS;
5676                 BTRFS_I(inode)->flags |= BTRFS_INODE_COMPRESS;
5677         }
5678
5679         if (flags & BTRFS_INODE_NODATACOW) {
5680                 BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW;
5681                 if (S_ISREG(inode->i_mode))
5682                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM;
5683         }
5684
5685         btrfs_sync_inode_flags_to_i_flags(inode);
5686 }
5687
5688 static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
5689                                      struct btrfs_root *root,
5690                                      struct inode *dir,
5691                                      const char *name, int name_len,
5692                                      u64 ref_objectid, u64 objectid,
5693                                      umode_t mode, u64 *index)
5694 {
5695         struct btrfs_fs_info *fs_info = root->fs_info;
5696         struct inode *inode;
5697         struct btrfs_inode_item *inode_item;
5698         struct btrfs_key *location;
5699         struct btrfs_path *path;
5700         struct btrfs_inode_ref *ref;
5701         struct btrfs_key key[2];
5702         u32 sizes[2];
5703         int nitems = name ? 2 : 1;
5704         unsigned long ptr;
5705         unsigned int nofs_flag;
5706         int ret;
5707
5708         path = btrfs_alloc_path();
5709         if (!path)
5710                 return ERR_PTR(-ENOMEM);
5711
5712         nofs_flag = memalloc_nofs_save();
5713         inode = new_inode(fs_info->sb);
5714         memalloc_nofs_restore(nofs_flag);
5715         if (!inode) {
5716                 btrfs_free_path(path);
5717                 return ERR_PTR(-ENOMEM);
5718         }
5719
5720         /*
5721          * O_TMPFILE, set link count to 0, so that after this point,
5722          * we fill in an inode item with the correct link count.
5723          */
5724         if (!name)
5725                 set_nlink(inode, 0);
5726
5727         /*
5728          * we have to initialize this early, so we can reclaim the inode
5729          * number if we fail afterwards in this function.
5730          */
5731         inode->i_ino = objectid;
5732
5733         if (dir && name) {
5734                 trace_btrfs_inode_request(dir);
5735
5736                 ret = btrfs_set_inode_index(BTRFS_I(dir), index);
5737                 if (ret) {
5738                         btrfs_free_path(path);
5739                         iput(inode);
5740                         return ERR_PTR(ret);
5741                 }
5742         } else if (dir) {
5743                 *index = 0;
5744         }
5745         /*
5746          * index_cnt is ignored for everything but a dir,
5747          * btrfs_set_inode_index_count has an explanation for the magic
5748          * number
5749          */
5750         BTRFS_I(inode)->index_cnt = 2;
5751         BTRFS_I(inode)->dir_index = *index;
5752         BTRFS_I(inode)->root = root;
5753         BTRFS_I(inode)->generation = trans->transid;
5754         inode->i_generation = BTRFS_I(inode)->generation;
5755
5756         /*
5757          * We could have gotten an inode number from somebody who was fsynced
5758          * and then removed in this same transaction, so let's just set full
5759          * sync since it will be a full sync anyway and this will blow away the
5760          * old info in the log.
5761          */
5762         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
5763
5764         key[0].objectid = objectid;
5765         key[0].type = BTRFS_INODE_ITEM_KEY;
5766         key[0].offset = 0;
5767
5768         sizes[0] = sizeof(struct btrfs_inode_item);
5769
5770         if (name) {
5771                 /*
5772                  * Start new inodes with an inode_ref. This is slightly more
5773                  * efficient for small numbers of hard links since they will
5774                  * be packed into one item. Extended refs will kick in if we
5775                  * add more hard links than can fit in the ref item.
5776                  */
5777                 key[1].objectid = objectid;
5778                 key[1].type = BTRFS_INODE_REF_KEY;
5779                 key[1].offset = ref_objectid;
5780
5781                 sizes[1] = name_len + sizeof(*ref);
5782         }
5783
5784         location = &BTRFS_I(inode)->location;
5785         location->objectid = objectid;
5786         location->offset = 0;
5787         location->type = BTRFS_INODE_ITEM_KEY;
5788
5789         ret = btrfs_insert_inode_locked(inode);
5790         if (ret < 0) {
5791                 iput(inode);
5792                 goto fail;
5793         }
5794
5795         path->leave_spinning = 1;
5796         ret = btrfs_insert_empty_items(trans, root, path, key, sizes, nitems);
5797         if (ret != 0)
5798                 goto fail_unlock;
5799
5800         inode_init_owner(inode, dir, mode);
5801         inode_set_bytes(inode, 0);
5802
5803         inode->i_mtime = current_time(inode);
5804         inode->i_atime = inode->i_mtime;
5805         inode->i_ctime = inode->i_mtime;
5806         BTRFS_I(inode)->i_otime = inode->i_mtime;
5807
5808         inode_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
5809                                   struct btrfs_inode_item);
5810         memzero_extent_buffer(path->nodes[0], (unsigned long)inode_item,
5811                              sizeof(*inode_item));
5812         fill_inode_item(trans, path->nodes[0], inode_item, inode);
5813
5814         if (name) {
5815                 ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
5816                                      struct btrfs_inode_ref);
5817                 btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
5818                 btrfs_set_inode_ref_index(path->nodes[0], ref, *index);
5819                 ptr = (unsigned long)(ref + 1);
5820                 write_extent_buffer(path->nodes[0], name, ptr, name_len);
5821         }
5822
5823         btrfs_mark_buffer_dirty(path->nodes[0]);
5824         btrfs_free_path(path);
5825
5826         btrfs_inherit_iflags(inode, dir);
5827
5828         if (S_ISREG(mode)) {
5829                 if (btrfs_test_opt(fs_info, NODATASUM))
5830                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM;
5831                 if (btrfs_test_opt(fs_info, NODATACOW))
5832                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW |
5833                                 BTRFS_INODE_NODATASUM;
5834         }
5835
5836         inode_tree_add(inode);
5837
5838         trace_btrfs_inode_new(inode);
5839         btrfs_set_inode_last_trans(trans, inode);
5840
5841         btrfs_update_root_times(trans, root);
5842
5843         ret = btrfs_inode_inherit_props(trans, inode, dir);
5844         if (ret)
5845                 btrfs_err(fs_info,
5846                           "error inheriting props for ino %llu (root %llu): %d",
5847                         btrfs_ino(BTRFS_I(inode)), root->root_key.objectid, ret);
5848
5849         return inode;
5850
5851 fail_unlock:
5852         discard_new_inode(inode);
5853 fail:
5854         if (dir && name)
5855                 BTRFS_I(dir)->index_cnt--;
5856         btrfs_free_path(path);
5857         return ERR_PTR(ret);
5858 }
5859
5860 /*
5861  * utility function to add 'inode' into 'parent_inode' with
5862  * a give name and a given sequence number.
5863  * if 'add_backref' is true, also insert a backref from the
5864  * inode to the parent directory.
5865  */
5866 int btrfs_add_link(struct btrfs_trans_handle *trans,
5867                    struct btrfs_inode *parent_inode, struct btrfs_inode *inode,
5868                    const char *name, int name_len, int add_backref, u64 index)
5869 {
5870         int ret = 0;
5871         struct btrfs_key key;
5872         struct btrfs_root *root = parent_inode->root;
5873         u64 ino = btrfs_ino(inode);
5874         u64 parent_ino = btrfs_ino(parent_inode);
5875
5876         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
5877                 memcpy(&key, &inode->root->root_key, sizeof(key));
5878         } else {
5879                 key.objectid = ino;
5880                 key.type = BTRFS_INODE_ITEM_KEY;
5881                 key.offset = 0;
5882         }
5883
5884         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
5885                 ret = btrfs_add_root_ref(trans, key.objectid,
5886                                          root->root_key.objectid, parent_ino,
5887                                          index, name, name_len);
5888         } else if (add_backref) {
5889                 ret = btrfs_insert_inode_ref(trans, root, name, name_len, ino,
5890                                              parent_ino, index);
5891         }
5892
5893         /* Nothing to clean up yet */
5894         if (ret)
5895                 return ret;
5896
5897         ret = btrfs_insert_dir_item(trans, name, name_len, parent_inode, &key,
5898                                     btrfs_inode_type(&inode->vfs_inode), index);
5899         if (ret == -EEXIST || ret == -EOVERFLOW)
5900                 goto fail_dir_item;
5901         else if (ret) {
5902                 btrfs_abort_transaction(trans, ret);
5903                 return ret;
5904         }
5905
5906         btrfs_i_size_write(parent_inode, parent_inode->vfs_inode.i_size +
5907                            name_len * 2);
5908         inode_inc_iversion(&parent_inode->vfs_inode);
5909         /*
5910          * If we are replaying a log tree, we do not want to update the mtime
5911          * and ctime of the parent directory with the current time, since the
5912          * log replay procedure is responsible for setting them to their correct
5913          * values (the ones it had when the fsync was done).
5914          */
5915         if (!test_bit(BTRFS_FS_LOG_RECOVERING, &root->fs_info->flags)) {
5916                 struct timespec64 now = current_time(&parent_inode->vfs_inode);
5917
5918                 parent_inode->vfs_inode.i_mtime = now;
5919                 parent_inode->vfs_inode.i_ctime = now;
5920         }
5921         ret = btrfs_update_inode(trans, root, &parent_inode->vfs_inode);
5922         if (ret)
5923                 btrfs_abort_transaction(trans, ret);
5924         return ret;
5925
5926 fail_dir_item:
5927         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
5928                 u64 local_index;
5929                 int err;
5930                 err = btrfs_del_root_ref(trans, key.objectid,
5931                                          root->root_key.objectid, parent_ino,
5932                                          &local_index, name, name_len);
5933                 if (err)
5934                         btrfs_abort_transaction(trans, err);
5935         } else if (add_backref) {
5936                 u64 local_index;
5937                 int err;
5938
5939                 err = btrfs_del_inode_ref(trans, root, name, name_len,
5940                                           ino, parent_ino, &local_index);
5941                 if (err)
5942                         btrfs_abort_transaction(trans, err);
5943         }
5944
5945         /* Return the original error code */
5946         return ret;
5947 }
5948
5949 static int btrfs_add_nondir(struct btrfs_trans_handle *trans,
5950                             struct btrfs_inode *dir, struct dentry *dentry,
5951                             struct btrfs_inode *inode, int backref, u64 index)
5952 {
5953         int err = btrfs_add_link(trans, dir, inode,
5954                                  dentry->d_name.name, dentry->d_name.len,
5955                                  backref, index);
5956         if (err > 0)
5957                 err = -EEXIST;
5958         return err;
5959 }
5960
5961 static int btrfs_mknod(struct inode *dir, struct dentry *dentry,
5962                         umode_t mode, dev_t rdev)
5963 {
5964         struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
5965         struct btrfs_trans_handle *trans;
5966         struct btrfs_root *root = BTRFS_I(dir)->root;
5967         struct inode *inode = NULL;
5968         int err;
5969         u64 objectid;
5970         u64 index = 0;
5971
5972         /*
5973          * 2 for inode item and ref
5974          * 2 for dir items
5975          * 1 for xattr if selinux is on
5976          */
5977         trans = btrfs_start_transaction(root, 5);
5978         if (IS_ERR(trans))
5979                 return PTR_ERR(trans);
5980
5981         err = btrfs_find_free_ino(root, &objectid);
5982         if (err)
5983                 goto out_unlock;
5984
5985         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
5986                         dentry->d_name.len, btrfs_ino(BTRFS_I(dir)), objectid,
5987                         mode, &index);
5988         if (IS_ERR(inode)) {
5989                 err = PTR_ERR(inode);
5990                 inode = NULL;
5991                 goto out_unlock;
5992         }
5993
5994         /*
5995         * If the active LSM wants to access the inode during
5996         * d_instantiate it needs these. Smack checks to see
5997         * if the filesystem supports xattrs by looking at the
5998         * ops vector.
5999         */
6000         inode->i_op = &btrfs_special_inode_operations;
6001         init_special_inode(inode, inode->i_mode, rdev);
6002
6003         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
6004         if (err)
6005                 goto out_unlock;
6006
6007         err = btrfs_add_nondir(trans, BTRFS_I(dir), dentry, BTRFS_I(inode),
6008                         0, index);
6009         if (err)
6010                 goto out_unlock;
6011
6012         btrfs_update_inode(trans, root, inode);
6013         d_instantiate_new(dentry, inode);
6014
6015 out_unlock:
6016         btrfs_end_transaction(trans);
6017         btrfs_btree_balance_dirty(fs_info);
6018         if (err && inode) {
6019                 inode_dec_link_count(inode);
6020                 discard_new_inode(inode);
6021         }
6022         return err;
6023 }
6024
6025 static int btrfs_create(struct inode *dir, struct dentry *dentry,
6026                         umode_t mode, bool excl)
6027 {
6028         struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
6029         struct btrfs_trans_handle *trans;
6030         struct btrfs_root *root = BTRFS_I(dir)->root;
6031         struct inode *inode = NULL;
6032         int err;
6033         u64 objectid;
6034         u64 index = 0;
6035
6036         /*
6037          * 2 for inode item and ref
6038          * 2 for dir items
6039          * 1 for xattr if selinux is on
6040          */
6041         trans = btrfs_start_transaction(root, 5);
6042         if (IS_ERR(trans))
6043                 return PTR_ERR(trans);
6044
6045         err = btrfs_find_free_ino(root, &objectid);
6046         if (err)
6047                 goto out_unlock;
6048
6049         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
6050                         dentry->d_name.len, btrfs_ino(BTRFS_I(dir)), objectid,
6051                         mode, &index);
6052         if (IS_ERR(inode)) {
6053                 err = PTR_ERR(inode);
6054                 inode = NULL;
6055                 goto out_unlock;
6056         }
6057         /*
6058         * If the active LSM wants to access the inode during
6059         * d_instantiate it needs these. Smack checks to see
6060         * if the filesystem supports xattrs by looking at the
6061         * ops vector.
6062         */
6063         inode->i_fop = &btrfs_file_operations;
6064         inode->i_op = &btrfs_file_inode_operations;
6065         inode->i_mapping->a_ops = &btrfs_aops;
6066
6067         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
6068         if (err)
6069                 goto out_unlock;
6070
6071         err = btrfs_update_inode(trans, root, inode);
6072         if (err)
6073                 goto out_unlock;
6074
6075         err = btrfs_add_nondir(trans, BTRFS_I(dir), dentry, BTRFS_I(inode),
6076                         0, index);
6077         if (err)
6078                 goto out_unlock;
6079
6080         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
6081         d_instantiate_new(dentry, inode);
6082
6083 out_unlock:
6084         btrfs_end_transaction(trans);
6085         if (err && inode) {
6086                 inode_dec_link_count(inode);
6087                 discard_new_inode(inode);
6088         }
6089         btrfs_btree_balance_dirty(fs_info);
6090         return err;
6091 }
6092
6093 static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
6094                       struct dentry *dentry)
6095 {
6096         struct btrfs_trans_handle *trans = NULL;
6097         struct btrfs_root *root = BTRFS_I(dir)->root;
6098         struct inode *inode = d_inode(old_dentry);
6099         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
6100         u64 index;
6101         int err;
6102         int drop_inode = 0;
6103
6104         /* do not allow sys_link's with other subvols of the same device */
6105         if (root->root_key.objectid != BTRFS_I(inode)->root->root_key.objectid)
6106                 return -EXDEV;
6107
6108         if (inode->i_nlink >= BTRFS_LINK_MAX)
6109                 return -EMLINK;
6110
6111         err = btrfs_set_inode_index(BTRFS_I(dir), &index);
6112         if (err)
6113                 goto fail;
6114
6115         /*
6116          * 2 items for inode and inode ref
6117          * 2 items for dir items
6118          * 1 item for parent inode
6119          * 1 item for orphan item deletion if O_TMPFILE
6120          */
6121         trans = btrfs_start_transaction(root, inode->i_nlink ? 5 : 6);
6122         if (IS_ERR(trans)) {
6123                 err = PTR_ERR(trans);
6124                 trans = NULL;
6125                 goto fail;
6126         }
6127
6128         /* There are several dir indexes for this inode, clear the cache. */
6129         BTRFS_I(inode)->dir_index = 0ULL;
6130         inc_nlink(inode);
6131         inode_inc_iversion(inode);
6132         inode->i_ctime = current_time(inode);
6133         ihold(inode);
6134         set_bit(BTRFS_INODE_COPY_EVERYTHING, &BTRFS_I(inode)->runtime_flags);
6135
6136         err = btrfs_add_nondir(trans, BTRFS_I(dir), dentry, BTRFS_I(inode),
6137                         1, index);
6138
6139         if (err) {
6140                 drop_inode = 1;
6141         } else {
6142                 struct dentry *parent = dentry->d_parent;
6143                 int ret;
6144
6145                 err = btrfs_update_inode(trans, root, inode);
6146                 if (err)
6147                         goto fail;
6148                 if (inode->i_nlink == 1) {
6149                         /*
6150                          * If new hard link count is 1, it's a file created
6151                          * with open(2) O_TMPFILE flag.
6152                          */
6153                         err = btrfs_orphan_del(trans, BTRFS_I(inode));
6154                         if (err)
6155                                 goto fail;
6156                 }
6157                 d_instantiate(dentry, inode);
6158                 ret = btrfs_log_new_name(trans, BTRFS_I(inode), NULL, parent,
6159                                          true, NULL);
6160                 if (ret == BTRFS_NEED_TRANS_COMMIT) {
6161                         err = btrfs_commit_transaction(trans);
6162                         trans = NULL;
6163                 }
6164         }
6165
6166 fail:
6167         if (trans)
6168                 btrfs_end_transaction(trans);
6169         if (drop_inode) {
6170                 inode_dec_link_count(inode);
6171                 iput(inode);
6172         }
6173         btrfs_btree_balance_dirty(fs_info);
6174         return err;
6175 }
6176
6177 static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
6178 {
6179         struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
6180         struct inode *inode = NULL;
6181         struct btrfs_trans_handle *trans;
6182         struct btrfs_root *root = BTRFS_I(dir)->root;
6183         int err = 0;
6184         u64 objectid = 0;
6185         u64 index = 0;
6186
6187         /*
6188          * 2 items for inode and ref
6189          * 2 items for dir items
6190          * 1 for xattr if selinux is on
6191          */
6192         trans = btrfs_start_transaction(root, 5);
6193         if (IS_ERR(trans))
6194                 return PTR_ERR(trans);
6195
6196         err = btrfs_find_free_ino(root, &objectid);
6197         if (err)
6198                 goto out_fail;
6199
6200         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
6201                         dentry->d_name.len, btrfs_ino(BTRFS_I(dir)), objectid,
6202                         S_IFDIR | mode, &index);
6203         if (IS_ERR(inode)) {
6204                 err = PTR_ERR(inode);
6205                 inode = NULL;
6206                 goto out_fail;
6207         }
6208
6209         /* these must be set before we unlock the inode */
6210         inode->i_op = &btrfs_dir_inode_operations;
6211         inode->i_fop = &btrfs_dir_file_operations;
6212
6213         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
6214         if (err)
6215                 goto out_fail;
6216
6217         btrfs_i_size_write(BTRFS_I(inode), 0);
6218         err = btrfs_update_inode(trans, root, inode);
6219         if (err)
6220                 goto out_fail;
6221
6222         err = btrfs_add_link(trans, BTRFS_I(dir), BTRFS_I(inode),
6223                         dentry->d_name.name,
6224                         dentry->d_name.len, 0, index);
6225         if (err)
6226                 goto out_fail;
6227
6228         d_instantiate_new(dentry, inode);
6229
6230 out_fail:
6231         btrfs_end_transaction(trans);
6232         if (err && inode) {
6233                 inode_dec_link_count(inode);
6234                 discard_new_inode(inode);
6235         }
6236         btrfs_btree_balance_dirty(fs_info);
6237         return err;
6238 }
6239
6240 static noinline int uncompress_inline(struct btrfs_path *path,
6241                                       struct page *page,
6242                                       size_t pg_offset, u64 extent_offset,
6243                                       struct btrfs_file_extent_item *item)
6244 {
6245         int ret;
6246         struct extent_buffer *leaf = path->nodes[0];
6247         char *tmp;
6248         size_t max_size;
6249         unsigned long inline_size;
6250         unsigned long ptr;
6251         int compress_type;
6252
6253         WARN_ON(pg_offset != 0);
6254         compress_type = btrfs_file_extent_compression(leaf, item);
6255         max_size = btrfs_file_extent_ram_bytes(leaf, item);
6256         inline_size = btrfs_file_extent_inline_item_len(leaf,
6257                                         btrfs_item_nr(path->slots[0]));
6258         tmp = kmalloc(inline_size, GFP_NOFS);
6259         if (!tmp)
6260                 return -ENOMEM;
6261         ptr = btrfs_file_extent_inline_start(item);
6262
6263         read_extent_buffer(leaf, tmp, ptr, inline_size);
6264
6265         max_size = min_t(unsigned long, PAGE_SIZE, max_size);
6266         ret = btrfs_decompress(compress_type, tmp, page,
6267                                extent_offset, inline_size, max_size);
6268
6269         /*
6270          * decompression code contains a memset to fill in any space between the end
6271          * of the uncompressed data and the end of max_size in case the decompressed
6272          * data ends up shorter than ram_bytes.  That doesn't cover the hole between
6273          * the end of an inline extent and the beginning of the next block, so we
6274          * cover that region here.
6275          */
6276
6277         if (max_size + pg_offset < PAGE_SIZE) {
6278                 char *map = kmap(page);
6279                 memset(map + pg_offset + max_size, 0, PAGE_SIZE - max_size - pg_offset);
6280                 kunmap(page);
6281         }
6282         kfree(tmp);
6283         return ret;
6284 }
6285
6286 /**
6287  * btrfs_get_extent - Lookup the first extent overlapping a range in a file.
6288  * @inode:      file to search in
6289  * @page:       page to read extent data into if the extent is inline
6290  * @pg_offset:  offset into @page to copy to
6291  * @start:      file offset
6292  * @len:        length of range starting at @start
6293  *
6294  * This returns the first &struct extent_map which overlaps with the given
6295  * range, reading it from the B-tree and caching it if necessary. Note that
6296  * there may be more extents which overlap the given range after the returned
6297  * extent_map.
6298  *
6299  * If @page is not NULL and the extent is inline, this also reads the extent
6300  * data directly into the page and marks the extent up to date in the io_tree.
6301  *
6302  * Return: ERR_PTR on error, non-NULL extent_map on success.
6303  */
6304 struct extent_map *btrfs_get_extent(struct btrfs_inode *inode,
6305                                     struct page *page, size_t pg_offset,
6306                                     u64 start, u64 len)
6307 {
6308         struct btrfs_fs_info *fs_info = inode->root->fs_info;
6309         int ret;
6310         int err = 0;
6311         u64 extent_start = 0;
6312         u64 extent_end = 0;
6313         u64 objectid = btrfs_ino(inode);
6314         int extent_type = -1;
6315         struct btrfs_path *path = NULL;
6316         struct btrfs_root *root = inode->root;
6317         struct btrfs_file_extent_item *item;
6318         struct extent_buffer *leaf;
6319         struct btrfs_key found_key;
6320         struct extent_map *em = NULL;
6321         struct extent_map_tree *em_tree = &inode->extent_tree;
6322         struct extent_io_tree *io_tree = &inode->io_tree;
6323
6324         read_lock(&em_tree->lock);
6325         em = lookup_extent_mapping(em_tree, start, len);
6326         read_unlock(&em_tree->lock);
6327
6328         if (em) {
6329                 if (em->start > start || em->start + em->len <= start)
6330                         free_extent_map(em);
6331                 else if (em->block_start == EXTENT_MAP_INLINE && page)
6332                         free_extent_map(em);
6333                 else
6334                         goto out;
6335         }
6336         em = alloc_extent_map();
6337         if (!em) {
6338                 err = -ENOMEM;
6339                 goto out;
6340         }
6341         em->start = EXTENT_MAP_HOLE;
6342         em->orig_start = EXTENT_MAP_HOLE;
6343         em->len = (u64)-1;
6344         em->block_len = (u64)-1;
6345
6346         path = btrfs_alloc_path();
6347         if (!path) {
6348                 err = -ENOMEM;
6349                 goto out;
6350         }
6351
6352         /* Chances are we'll be called again, so go ahead and do readahead */
6353         path->reada = READA_FORWARD;
6354
6355         /*
6356          * Unless we're going to uncompress the inline extent, no sleep would
6357          * happen.
6358          */
6359         path->leave_spinning = 1;
6360
6361         ret = btrfs_lookup_file_extent(NULL, root, path, objectid, start, 0);
6362         if (ret < 0) {
6363                 err = ret;
6364                 goto out;
6365         } else if (ret > 0) {
6366                 if (path->slots[0] == 0)
6367                         goto not_found;
6368                 path->slots[0]--;
6369         }
6370
6371         leaf = path->nodes[0];
6372         item = btrfs_item_ptr(leaf, path->slots[0],
6373                               struct btrfs_file_extent_item);
6374         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6375         if (found_key.objectid != objectid ||
6376             found_key.type != BTRFS_EXTENT_DATA_KEY) {
6377                 /*
6378                  * If we backup past the first extent we want to move forward
6379                  * and see if there is an extent in front of us, otherwise we'll
6380                  * say there is a hole for our whole search range which can
6381                  * cause problems.
6382                  */
6383                 extent_end = start;
6384                 goto next;
6385         }
6386
6387         extent_type = btrfs_file_extent_type(leaf, item);
6388         extent_start = found_key.offset;
6389         if (extent_type == BTRFS_FILE_EXTENT_REG ||
6390             extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
6391                 /* Only regular file could have regular/prealloc extent */
6392                 if (!S_ISREG(inode->vfs_inode.i_mode)) {
6393                         ret = -EUCLEAN;
6394                         btrfs_crit(fs_info,
6395                 "regular/prealloc extent found for non-regular inode %llu",
6396                                    btrfs_ino(inode));
6397                         goto out;
6398                 }
6399                 extent_end = extent_start +
6400                        btrfs_file_extent_num_bytes(leaf, item);
6401
6402                 trace_btrfs_get_extent_show_fi_regular(inode, leaf, item,
6403                                                        extent_start);
6404         } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
6405                 size_t size;
6406
6407                 size = btrfs_file_extent_ram_bytes(leaf, item);
6408                 extent_end = ALIGN(extent_start + size,
6409                                    fs_info->sectorsize);
6410
6411                 trace_btrfs_get_extent_show_fi_inline(inode, leaf, item,
6412                                                       path->slots[0],
6413                                                       extent_start);
6414         }
6415 next:
6416         if (start >= extent_end) {
6417                 path->slots[0]++;
6418                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
6419                         ret = btrfs_next_leaf(root, path);
6420                         if (ret < 0) {
6421                                 err = ret;
6422                                 goto out;
6423                         } else if (ret > 0) {
6424                                 goto not_found;
6425                         }
6426                         leaf = path->nodes[0];
6427                 }
6428                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6429                 if (found_key.objectid != objectid ||
6430                     found_key.type != BTRFS_EXTENT_DATA_KEY)
6431                         goto not_found;
6432                 if (start + len <= found_key.offset)
6433                         goto not_found;
6434                 if (start > found_key.offset)
6435                         goto next;
6436
6437                 /* New extent overlaps with existing one */
6438                 em->start = start;
6439                 em->orig_start = start;
6440                 em->len = found_key.offset - start;
6441                 em->block_start = EXTENT_MAP_HOLE;
6442                 goto insert;
6443         }
6444
6445         btrfs_extent_item_to_extent_map(inode, path, item, !page, em);
6446
6447         if (extent_type == BTRFS_FILE_EXTENT_REG ||
6448             extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
6449                 goto insert;
6450         } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
6451                 unsigned long ptr;
6452                 char *map;
6453                 size_t size;
6454                 size_t extent_offset;
6455                 size_t copy_size;
6456
6457                 if (!page)
6458                         goto out;
6459
6460                 size = btrfs_file_extent_ram_bytes(leaf, item);
6461                 extent_offset = page_offset(page) + pg_offset - extent_start;
6462                 copy_size = min_t(u64, PAGE_SIZE - pg_offset,
6463                                   size - extent_offset);
6464                 em->start = extent_start + extent_offset;
6465                 em->len = ALIGN(copy_size, fs_info->sectorsize);
6466                 em->orig_block_len = em->len;
6467                 em->orig_start = em->start;
6468                 ptr = btrfs_file_extent_inline_start(item) + extent_offset;
6469
6470                 btrfs_set_path_blocking(path);
6471                 if (!PageUptodate(page)) {
6472                         if (btrfs_file_extent_compression(leaf, item) !=
6473                             BTRFS_COMPRESS_NONE) {
6474                                 ret = uncompress_inline(path, page, pg_offset,
6475                                                         extent_offset, item);
6476                                 if (ret) {
6477                                         err = ret;
6478                                         goto out;
6479                                 }
6480                         } else {
6481                                 map = kmap(page);
6482                                 read_extent_buffer(leaf, map + pg_offset, ptr,
6483                                                    copy_size);
6484                                 if (pg_offset + copy_size < PAGE_SIZE) {
6485                                         memset(map + pg_offset + copy_size, 0,
6486                                                PAGE_SIZE - pg_offset -
6487                                                copy_size);
6488                                 }
6489                                 kunmap(page);
6490                         }
6491                         flush_dcache_page(page);
6492                 }
6493                 set_extent_uptodate(io_tree, em->start,
6494                                     extent_map_end(em) - 1, NULL, GFP_NOFS);
6495                 goto insert;
6496         }
6497 not_found:
6498         em->start = start;
6499         em->orig_start = start;
6500         em->len = len;
6501         em->block_start = EXTENT_MAP_HOLE;
6502 insert:
6503         btrfs_release_path(path);
6504         if (em->start > start || extent_map_end(em) <= start) {
6505                 btrfs_err(fs_info,
6506                           "bad extent! em: [%llu %llu] passed [%llu %llu]",
6507                           em->start, em->len, start, len);
6508                 err = -EIO;
6509                 goto out;
6510         }
6511
6512         err = 0;
6513         write_lock(&em_tree->lock);
6514         err = btrfs_add_extent_mapping(fs_info, em_tree, &em, start, len);
6515         write_unlock(&em_tree->lock);
6516 out:
6517         btrfs_free_path(path);
6518
6519         trace_btrfs_get_extent(root, inode, em);
6520
6521         if (err) {
6522                 free_extent_map(em);
6523                 return ERR_PTR(err);
6524         }
6525         BUG_ON(!em); /* Error is always set */
6526         return em;
6527 }
6528
6529 struct extent_map *btrfs_get_extent_fiemap(struct btrfs_inode *inode,
6530                                            u64 start, u64 len)
6531 {
6532         struct extent_map *em;
6533         struct extent_map *hole_em = NULL;
6534         u64 delalloc_start = start;
6535         u64 end;
6536         u64 delalloc_len;
6537         u64 delalloc_end;
6538         int err = 0;
6539
6540         em = btrfs_get_extent(inode, NULL, 0, start, len);
6541         if (IS_ERR(em))
6542                 return em;
6543         /*
6544          * If our em maps to:
6545          * - a hole or
6546          * - a pre-alloc extent,
6547          * there might actually be delalloc bytes behind it.
6548          */
6549         if (em->block_start != EXTENT_MAP_HOLE &&
6550             !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
6551                 return em;
6552         else
6553                 hole_em = em;
6554
6555         /* check to see if we've wrapped (len == -1 or similar) */
6556         end = start + len;
6557         if (end < start)
6558                 end = (u64)-1;
6559         else
6560                 end -= 1;
6561
6562         em = NULL;
6563
6564         /* ok, we didn't find anything, lets look for delalloc */
6565         delalloc_len = count_range_bits(&inode->io_tree, &delalloc_start,
6566                                  end, len, EXTENT_DELALLOC, 1);
6567         delalloc_end = delalloc_start + delalloc_len;
6568         if (delalloc_end < delalloc_start)
6569                 delalloc_end = (u64)-1;
6570
6571         /*
6572          * We didn't find anything useful, return the original results from
6573          * get_extent()
6574          */
6575         if (delalloc_start > end || delalloc_end <= start) {
6576                 em = hole_em;
6577                 hole_em = NULL;
6578                 goto out;
6579         }
6580
6581         /*
6582          * Adjust the delalloc_start to make sure it doesn't go backwards from
6583          * the start they passed in
6584          */
6585         delalloc_start = max(start, delalloc_start);
6586         delalloc_len = delalloc_end - delalloc_start;
6587
6588         if (delalloc_len > 0) {
6589                 u64 hole_start;
6590                 u64 hole_len;
6591                 const u64 hole_end = extent_map_end(hole_em);
6592
6593                 em = alloc_extent_map();
6594                 if (!em) {
6595                         err = -ENOMEM;
6596                         goto out;
6597                 }
6598
6599                 ASSERT(hole_em);
6600                 /*
6601                  * When btrfs_get_extent can't find anything it returns one
6602                  * huge hole
6603                  *
6604                  * Make sure what it found really fits our range, and adjust to
6605                  * make sure it is based on the start from the caller
6606                  */
6607                 if (hole_end <= start || hole_em->start > end) {
6608                        free_extent_map(hole_em);
6609                        hole_em = NULL;
6610                 } else {
6611                        hole_start = max(hole_em->start, start);
6612                        hole_len = hole_end - hole_start;
6613                 }
6614
6615                 if (hole_em && delalloc_start > hole_start) {
6616                         /*
6617                          * Our hole starts before our delalloc, so we have to
6618                          * return just the parts of the hole that go until the
6619                          * delalloc starts
6620                          */
6621                         em->len = min(hole_len, delalloc_start - hole_start);
6622                         em->start = hole_start;
6623                         em->orig_start = hole_start;
6624                         /*
6625                          * Don't adjust block start at all, it is fixed at
6626                          * EXTENT_MAP_HOLE
6627                          */
6628                         em->block_start = hole_em->block_start;
6629                         em->block_len = hole_len;
6630                         if (test_bit(EXTENT_FLAG_PREALLOC, &hole_em->flags))
6631                                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
6632                 } else {
6633                         /*
6634                          * Hole is out of passed range or it starts after
6635                          * delalloc range
6636                          */
6637                         em->start = delalloc_start;
6638                         em->len = delalloc_len;
6639                         em->orig_start = delalloc_start;
6640                         em->block_start = EXTENT_MAP_DELALLOC;
6641                         em->block_len = delalloc_len;
6642                 }
6643         } else {
6644                 return hole_em;
6645         }
6646 out:
6647
6648         free_extent_map(hole_em);
6649         if (err) {
6650                 free_extent_map(em);
6651                 return ERR_PTR(err);
6652         }
6653         return em;
6654 }
6655
6656 static struct extent_map *btrfs_create_dio_extent(struct inode *inode,
6657                                                   const u64 start,
6658                                                   const u64 len,
6659                                                   const u64 orig_start,
6660                                                   const u64 block_start,
6661                                                   const u64 block_len,
6662                                                   const u64 orig_block_len,
6663                                                   const u64 ram_bytes,
6664                                                   const int type)
6665 {
6666         struct extent_map *em = NULL;
6667         int ret;
6668
6669         if (type != BTRFS_ORDERED_NOCOW) {
6670                 em = create_io_em(inode, start, len, orig_start,
6671                                   block_start, block_len, orig_block_len,
6672                                   ram_bytes,
6673                                   BTRFS_COMPRESS_NONE, /* compress_type */
6674                                   type);
6675                 if (IS_ERR(em))
6676                         goto out;
6677         }
6678         ret = btrfs_add_ordered_extent_dio(inode, start, block_start,
6679                                            len, block_len, type);
6680         if (ret) {
6681                 if (em) {
6682                         free_extent_map(em);
6683                         btrfs_drop_extent_cache(BTRFS_I(inode), start,
6684                                                 start + len - 1, 0);
6685                 }
6686                 em = ERR_PTR(ret);
6687         }
6688  out:
6689
6690         return em;
6691 }
6692
6693 static struct extent_map *btrfs_new_extent_direct(struct inode *inode,
6694                                                   u64 start, u64 len)
6695 {
6696         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
6697         struct btrfs_root *root = BTRFS_I(inode)->root;
6698         struct extent_map *em;
6699         struct btrfs_key ins;
6700         u64 alloc_hint;
6701         int ret;
6702
6703         alloc_hint = get_extent_allocation_hint(inode, start, len);
6704         ret = btrfs_reserve_extent(root, len, len, fs_info->sectorsize,
6705                                    0, alloc_hint, &ins, 1, 1);
6706         if (ret)
6707                 return ERR_PTR(ret);
6708
6709         em = btrfs_create_dio_extent(inode, start, ins.offset, start,
6710                                      ins.objectid, ins.offset, ins.offset,
6711                                      ins.offset, BTRFS_ORDERED_REGULAR);
6712         btrfs_dec_block_group_reservations(fs_info, ins.objectid);
6713         if (IS_ERR(em))
6714                 btrfs_free_reserved_extent(fs_info, ins.objectid,
6715                                            ins.offset, 1);
6716
6717         return em;
6718 }
6719
6720 /*
6721  * returns 1 when the nocow is safe, < 1 on error, 0 if the
6722  * block must be cow'd
6723  */
6724 noinline int can_nocow_extent(struct inode *inode, u64 offset, u64 *len,
6725                               u64 *orig_start, u64 *orig_block_len,
6726                               u64 *ram_bytes)
6727 {
6728         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
6729         struct btrfs_path *path;
6730         int ret;
6731         struct extent_buffer *leaf;
6732         struct btrfs_root *root = BTRFS_I(inode)->root;
6733         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
6734         struct btrfs_file_extent_item *fi;
6735         struct btrfs_key key;
6736         u64 disk_bytenr;
6737         u64 backref_offset;
6738         u64 extent_end;
6739         u64 num_bytes;
6740         int slot;
6741         int found_type;
6742         bool nocow = (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW);
6743
6744         path = btrfs_alloc_path();
6745         if (!path)
6746                 return -ENOMEM;
6747
6748         ret = btrfs_lookup_file_extent(NULL, root, path,
6749                         btrfs_ino(BTRFS_I(inode)), offset, 0);
6750         if (ret < 0)
6751                 goto out;
6752
6753         slot = path->slots[0];
6754         if (ret == 1) {
6755                 if (slot == 0) {
6756                         /* can't find the item, must cow */
6757                         ret = 0;
6758                         goto out;
6759                 }
6760                 slot--;
6761         }
6762         ret = 0;
6763         leaf = path->nodes[0];
6764         btrfs_item_key_to_cpu(leaf, &key, slot);
6765         if (key.objectid != btrfs_ino(BTRFS_I(inode)) ||
6766             key.type != BTRFS_EXTENT_DATA_KEY) {
6767                 /* not our file or wrong item type, must cow */
6768                 goto out;
6769         }
6770
6771         if (key.offset > offset) {
6772                 /* Wrong offset, must cow */
6773                 goto out;
6774         }
6775
6776         fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
6777         found_type = btrfs_file_extent_type(leaf, fi);
6778         if (found_type != BTRFS_FILE_EXTENT_REG &&
6779             found_type != BTRFS_FILE_EXTENT_PREALLOC) {
6780                 /* not a regular extent, must cow */
6781                 goto out;
6782         }
6783
6784         if (!nocow && found_type == BTRFS_FILE_EXTENT_REG)
6785                 goto out;
6786
6787         extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
6788         if (extent_end <= offset)
6789                 goto out;
6790
6791         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
6792         if (disk_bytenr == 0)
6793                 goto out;
6794
6795         if (btrfs_file_extent_compression(leaf, fi) ||
6796             btrfs_file_extent_encryption(leaf, fi) ||
6797             btrfs_file_extent_other_encoding(leaf, fi))
6798                 goto out;
6799
6800         /*
6801          * Do the same check as in btrfs_cross_ref_exist but without the
6802          * unnecessary search.
6803          */
6804         if (btrfs_file_extent_generation(leaf, fi) <=
6805             btrfs_root_last_snapshot(&root->root_item))
6806                 goto out;
6807
6808         backref_offset = btrfs_file_extent_offset(leaf, fi);
6809
6810         if (orig_start) {
6811                 *orig_start = key.offset - backref_offset;
6812                 *orig_block_len = btrfs_file_extent_disk_num_bytes(leaf, fi);
6813                 *ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
6814         }
6815
6816         if (btrfs_extent_readonly(fs_info, disk_bytenr))
6817                 goto out;
6818
6819         num_bytes = min(offset + *len, extent_end) - offset;
6820         if (!nocow && found_type == BTRFS_FILE_EXTENT_PREALLOC) {
6821                 u64 range_end;
6822
6823                 range_end = round_up(offset + num_bytes,
6824                                      root->fs_info->sectorsize) - 1;
6825                 ret = test_range_bit(io_tree, offset, range_end,
6826                                      EXTENT_DELALLOC, 0, NULL);
6827                 if (ret) {
6828                         ret = -EAGAIN;
6829                         goto out;
6830                 }
6831         }
6832
6833         btrfs_release_path(path);
6834
6835         /*
6836          * look for other files referencing this extent, if we
6837          * find any we must cow
6838          */
6839
6840         ret = btrfs_cross_ref_exist(root, btrfs_ino(BTRFS_I(inode)),
6841                                     key.offset - backref_offset, disk_bytenr);
6842         if (ret) {
6843                 ret = 0;
6844                 goto out;
6845         }
6846
6847         /*
6848          * adjust disk_bytenr and num_bytes to cover just the bytes
6849          * in this extent we are about to write.  If there
6850          * are any csums in that range we have to cow in order
6851          * to keep the csums correct
6852          */
6853         disk_bytenr += backref_offset;
6854         disk_bytenr += offset - key.offset;
6855         if (csum_exist_in_range(fs_info, disk_bytenr, num_bytes))
6856                 goto out;
6857         /*
6858          * all of the above have passed, it is safe to overwrite this extent
6859          * without cow
6860          */
6861         *len = num_bytes;
6862         ret = 1;
6863 out:
6864         btrfs_free_path(path);
6865         return ret;
6866 }
6867
6868 static int lock_extent_direct(struct inode *inode, u64 lockstart, u64 lockend,
6869                               struct extent_state **cached_state, int writing)
6870 {
6871         struct btrfs_ordered_extent *ordered;
6872         int ret = 0;
6873
6874         while (1) {
6875                 lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend,
6876                                  cached_state);
6877                 /*
6878                  * We're concerned with the entire range that we're going to be
6879                  * doing DIO to, so we need to make sure there's no ordered
6880                  * extents in this range.
6881                  */
6882                 ordered = btrfs_lookup_ordered_range(BTRFS_I(inode), lockstart,
6883                                                      lockend - lockstart + 1);
6884
6885                 /*
6886                  * We need to make sure there are no buffered pages in this
6887                  * range either, we could have raced between the invalidate in
6888                  * generic_file_direct_write and locking the extent.  The
6889                  * invalidate needs to happen so that reads after a write do not
6890                  * get stale data.
6891                  */
6892                 if (!ordered &&
6893                     (!writing || !filemap_range_has_page(inode->i_mapping,
6894                                                          lockstart, lockend)))
6895                         break;
6896
6897                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
6898                                      cached_state);
6899
6900                 if (ordered) {
6901                         /*
6902                          * If we are doing a DIO read and the ordered extent we
6903                          * found is for a buffered write, we can not wait for it
6904                          * to complete and retry, because if we do so we can
6905                          * deadlock with concurrent buffered writes on page
6906                          * locks. This happens only if our DIO read covers more
6907                          * than one extent map, if at this point has already
6908                          * created an ordered extent for a previous extent map
6909                          * and locked its range in the inode's io tree, and a
6910                          * concurrent write against that previous extent map's
6911                          * range and this range started (we unlock the ranges
6912                          * in the io tree only when the bios complete and
6913                          * buffered writes always lock pages before attempting
6914                          * to lock range in the io tree).
6915                          */
6916                         if (writing ||
6917                             test_bit(BTRFS_ORDERED_DIRECT, &ordered->flags))
6918                                 btrfs_start_ordered_extent(inode, ordered, 1);
6919                         else
6920                                 ret = -ENOTBLK;
6921                         btrfs_put_ordered_extent(ordered);
6922                 } else {
6923                         /*
6924                          * We could trigger writeback for this range (and wait
6925                          * for it to complete) and then invalidate the pages for
6926                          * this range (through invalidate_inode_pages2_range()),
6927                          * but that can lead us to a deadlock with a concurrent
6928                          * call to readpages() (a buffered read or a defrag call
6929                          * triggered a readahead) on a page lock due to an
6930                          * ordered dio extent we created before but did not have
6931                          * yet a corresponding bio submitted (whence it can not
6932                          * complete), which makes readpages() wait for that
6933                          * ordered extent to complete while holding a lock on
6934                          * that page.
6935                          */
6936                         ret = -ENOTBLK;
6937                 }
6938
6939                 if (ret)
6940                         break;
6941
6942                 cond_resched();
6943         }
6944
6945         return ret;
6946 }
6947
6948 /* The callers of this must take lock_extent() */
6949 static struct extent_map *create_io_em(struct inode *inode, u64 start, u64 len,
6950                                        u64 orig_start, u64 block_start,
6951                                        u64 block_len, u64 orig_block_len,
6952                                        u64 ram_bytes, int compress_type,
6953                                        int type)
6954 {
6955         struct extent_map_tree *em_tree;
6956         struct extent_map *em;
6957         int ret;
6958
6959         ASSERT(type == BTRFS_ORDERED_PREALLOC ||
6960                type == BTRFS_ORDERED_COMPRESSED ||
6961                type == BTRFS_ORDERED_NOCOW ||
6962                type == BTRFS_ORDERED_REGULAR);
6963
6964         em_tree = &BTRFS_I(inode)->extent_tree;
6965         em = alloc_extent_map();
6966         if (!em)
6967                 return ERR_PTR(-ENOMEM);
6968
6969         em->start = start;
6970         em->orig_start = orig_start;
6971         em->len = len;
6972         em->block_len = block_len;
6973         em->block_start = block_start;
6974         em->orig_block_len = orig_block_len;
6975         em->ram_bytes = ram_bytes;
6976         em->generation = -1;
6977         set_bit(EXTENT_FLAG_PINNED, &em->flags);
6978         if (type == BTRFS_ORDERED_PREALLOC) {
6979                 set_bit(EXTENT_FLAG_FILLING, &em->flags);
6980         } else if (type == BTRFS_ORDERED_COMPRESSED) {
6981                 set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
6982                 em->compress_type = compress_type;
6983         }
6984
6985         do {
6986                 btrfs_drop_extent_cache(BTRFS_I(inode), em->start,
6987                                 em->start + em->len - 1, 0);
6988                 write_lock(&em_tree->lock);
6989                 ret = add_extent_mapping(em_tree, em, 1);
6990                 write_unlock(&em_tree->lock);
6991                 /*
6992                  * The caller has taken lock_extent(), who could race with us
6993                  * to add em?
6994                  */
6995         } while (ret == -EEXIST);
6996
6997         if (ret) {
6998                 free_extent_map(em);
6999                 return ERR_PTR(ret);
7000         }
7001
7002         /* em got 2 refs now, callers needs to do free_extent_map once. */
7003         return em;
7004 }
7005
7006
7007 static int btrfs_get_blocks_direct_read(struct extent_map *em,
7008                                         struct buffer_head *bh_result,
7009                                         struct inode *inode,
7010                                         u64 start, u64 len)
7011 {
7012         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
7013
7014         if (em->block_start == EXTENT_MAP_HOLE ||
7015                         test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
7016                 return -ENOENT;
7017
7018         len = min(len, em->len - (start - em->start));
7019
7020         bh_result->b_blocknr = (em->block_start + (start - em->start)) >>
7021                 inode->i_blkbits;
7022         bh_result->b_size = len;
7023         bh_result->b_bdev = fs_info->fs_devices->latest_bdev;
7024         set_buffer_mapped(bh_result);
7025
7026         return 0;
7027 }
7028
7029 static int btrfs_get_blocks_direct_write(struct extent_map **map,
7030                                          struct buffer_head *bh_result,
7031                                          struct inode *inode,
7032                                          struct btrfs_dio_data *dio_data,
7033                                          u64 start, u64 len)
7034 {
7035         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
7036         struct extent_map *em = *map;
7037         int ret = 0;
7038
7039         /*
7040          * We don't allocate a new extent in the following cases
7041          *
7042          * 1) The inode is marked as NODATACOW. In this case we'll just use the
7043          * existing extent.
7044          * 2) The extent is marked as PREALLOC. We're good to go here and can
7045          * just use the extent.
7046          *
7047          */
7048         if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags) ||
7049             ((BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) &&
7050              em->block_start != EXTENT_MAP_HOLE)) {
7051                 int type;
7052                 u64 block_start, orig_start, orig_block_len, ram_bytes;
7053
7054                 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
7055                         type = BTRFS_ORDERED_PREALLOC;
7056                 else
7057                         type = BTRFS_ORDERED_NOCOW;
7058                 len = min(len, em->len - (start - em->start));
7059                 block_start = em->block_start + (start - em->start);
7060
7061                 if (can_nocow_extent(inode, start, &len, &orig_start,
7062                                      &orig_block_len, &ram_bytes) == 1 &&
7063                     btrfs_inc_nocow_writers(fs_info, block_start)) {
7064                         struct extent_map *em2;
7065
7066                         em2 = btrfs_create_dio_extent(inode, start, len,
7067                                                       orig_start, block_start,
7068                                                       len, orig_block_len,
7069                                                       ram_bytes, type);
7070                         btrfs_dec_nocow_writers(fs_info, block_start);
7071                         if (type == BTRFS_ORDERED_PREALLOC) {
7072                                 free_extent_map(em);
7073                                 *map = em = em2;
7074                         }
7075
7076                         if (em2 && IS_ERR(em2)) {
7077                                 ret = PTR_ERR(em2);
7078                                 goto out;
7079                         }
7080                         /*
7081                          * For inode marked NODATACOW or extent marked PREALLOC,
7082                          * use the existing or preallocated extent, so does not
7083                          * need to adjust btrfs_space_info's bytes_may_use.
7084                          */
7085                         btrfs_free_reserved_data_space_noquota(inode, start,
7086                                                                len);
7087                         goto skip_cow;
7088                 }
7089         }
7090
7091         /* this will cow the extent */
7092         len = bh_result->b_size;
7093         free_extent_map(em);
7094         *map = em = btrfs_new_extent_direct(inode, start, len);
7095         if (IS_ERR(em)) {
7096                 ret = PTR_ERR(em);
7097                 goto out;
7098         }
7099
7100         len = min(len, em->len - (start - em->start));
7101
7102 skip_cow:
7103         bh_result->b_blocknr = (em->block_start + (start - em->start)) >>
7104                 inode->i_blkbits;
7105         bh_result->b_size = len;
7106         bh_result->b_bdev = fs_info->fs_devices->latest_bdev;
7107         set_buffer_mapped(bh_result);
7108
7109         if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
7110                 set_buffer_new(bh_result);
7111
7112         /*
7113          * Need to update the i_size under the extent lock so buffered
7114          * readers will get the updated i_size when we unlock.
7115          */
7116         if (!dio_data->overwrite && start + len > i_size_read(inode))
7117                 i_size_write(inode, start + len);
7118
7119         WARN_ON(dio_data->reserve < len);
7120         dio_data->reserve -= len;
7121         dio_data->unsubmitted_oe_range_end = start + len;
7122         current->journal_info = dio_data;
7123 out:
7124         return ret;
7125 }
7126
7127 static int btrfs_get_blocks_direct(struct inode *inode, sector_t iblock,
7128                                    struct buffer_head *bh_result, int create)
7129 {
7130         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
7131         struct extent_map *em;
7132         struct extent_state *cached_state = NULL;
7133         struct btrfs_dio_data *dio_data = NULL;
7134         u64 start = iblock << inode->i_blkbits;
7135         u64 lockstart, lockend;
7136         u64 len = bh_result->b_size;
7137         int ret = 0;
7138
7139         if (!create)
7140                 len = min_t(u64, len, fs_info->sectorsize);
7141
7142         lockstart = start;
7143         lockend = start + len - 1;
7144
7145         if (current->journal_info) {
7146                 /*
7147                  * Need to pull our outstanding extents and set journal_info to NULL so
7148                  * that anything that needs to check if there's a transaction doesn't get
7149                  * confused.
7150                  */
7151                 dio_data = current->journal_info;
7152                 current->journal_info = NULL;
7153         }
7154
7155         /*
7156          * If this errors out it's because we couldn't invalidate pagecache for
7157          * this range and we need to fallback to buffered.
7158          */
7159         if (lock_extent_direct(inode, lockstart, lockend, &cached_state,
7160                                create)) {
7161                 ret = -ENOTBLK;
7162                 goto err;
7163         }
7164
7165         em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, start, len);
7166         if (IS_ERR(em)) {
7167                 ret = PTR_ERR(em);
7168                 goto unlock_err;
7169         }
7170
7171         /*
7172          * Ok for INLINE and COMPRESSED extents we need to fallback on buffered
7173          * io.  INLINE is special, and we could probably kludge it in here, but
7174          * it's still buffered so for safety lets just fall back to the generic
7175          * buffered path.
7176          *
7177          * For COMPRESSED we _have_ to read the entire extent in so we can
7178          * decompress it, so there will be buffering required no matter what we
7179          * do, so go ahead and fallback to buffered.
7180          *
7181          * We return -ENOTBLK because that's what makes DIO go ahead and go back
7182          * to buffered IO.  Don't blame me, this is the price we pay for using
7183          * the generic code.
7184          */
7185         if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags) ||
7186             em->block_start == EXTENT_MAP_INLINE) {
7187                 free_extent_map(em);
7188                 ret = -ENOTBLK;
7189                 goto unlock_err;
7190         }
7191
7192         if (create) {
7193                 ret = btrfs_get_blocks_direct_write(&em, bh_result, inode,
7194                                                     dio_data, start, len);
7195                 if (ret < 0)
7196                         goto unlock_err;
7197
7198                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart,
7199                                      lockend, &cached_state);
7200         } else {
7201                 ret = btrfs_get_blocks_direct_read(em, bh_result, inode,
7202                                                    start, len);
7203                 /* Can be negative only if we read from a hole */
7204                 if (ret < 0) {
7205                         ret = 0;
7206                         free_extent_map(em);
7207                         goto unlock_err;
7208                 }
7209                 /*
7210                  * We need to unlock only the end area that we aren't using.
7211                  * The rest is going to be unlocked by the endio routine.
7212                  */
7213                 lockstart = start + bh_result->b_size;
7214                 if (lockstart < lockend) {
7215                         unlock_extent_cached(&BTRFS_I(inode)->io_tree,
7216                                              lockstart, lockend, &cached_state);
7217                 } else {
7218                         free_extent_state(cached_state);
7219                 }
7220         }
7221
7222         free_extent_map(em);
7223
7224         return 0;
7225
7226 unlock_err:
7227         unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
7228                              &cached_state);
7229 err:
7230         if (dio_data)
7231                 current->journal_info = dio_data;
7232         return ret;
7233 }
7234
7235 static inline blk_status_t submit_dio_repair_bio(struct inode *inode,
7236                                                  struct bio *bio,
7237                                                  int mirror_num)
7238 {
7239         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
7240         blk_status_t ret;
7241
7242         BUG_ON(bio_op(bio) == REQ_OP_WRITE);
7243
7244         ret = btrfs_bio_wq_end_io(fs_info, bio, BTRFS_WQ_ENDIO_DIO_REPAIR);
7245         if (ret)
7246                 return ret;
7247
7248         ret = btrfs_map_bio(fs_info, bio, mirror_num);
7249
7250         return ret;
7251 }
7252
7253 static int btrfs_check_dio_repairable(struct inode *inode,
7254                                       struct bio *failed_bio,
7255                                       struct io_failure_record *failrec,
7256                                       int failed_mirror)
7257 {
7258         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
7259         int num_copies;
7260
7261         num_copies = btrfs_num_copies(fs_info, failrec->logical, failrec->len);
7262         if (num_copies == 1) {
7263                 /*
7264                  * we only have a single copy of the data, so don't bother with
7265                  * all the retry and error correction code that follows. no
7266                  * matter what the error is, it is very likely to persist.
7267                  */
7268                 btrfs_debug(fs_info,
7269                         "Check DIO Repairable: cannot repair, num_copies=%d, next_mirror %d, failed_mirror %d",
7270                         num_copies, failrec->this_mirror, failed_mirror);
7271                 return 0;
7272         }
7273
7274         failrec->failed_mirror = failed_mirror;
7275         failrec->this_mirror++;
7276         if (failrec->this_mirror == failed_mirror)
7277                 failrec->this_mirror++;
7278
7279         if (failrec->this_mirror > num_copies) {
7280                 btrfs_debug(fs_info,
7281                         "Check DIO Repairable: (fail) num_copies=%d, next_mirror %d, failed_mirror %d",
7282                         num_copies, failrec->this_mirror, failed_mirror);
7283                 return 0;
7284         }
7285
7286         return 1;
7287 }
7288
7289 static blk_status_t dio_read_error(struct inode *inode, struct bio *failed_bio,
7290                                    struct page *page, unsigned int pgoff,
7291                                    u64 start, u64 end, int failed_mirror,
7292                                    bio_end_io_t *repair_endio, void *repair_arg)
7293 {
7294         struct io_failure_record *failrec;
7295         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
7296         struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
7297         struct bio *bio;
7298         int isector;
7299         unsigned int read_mode = 0;
7300         int segs;
7301         int ret;
7302         blk_status_t status;
7303         struct bio_vec bvec;
7304
7305         BUG_ON(bio_op(failed_bio) == REQ_OP_WRITE);
7306
7307         ret = btrfs_get_io_failure_record(inode, start, end, &failrec);
7308         if (ret)
7309                 return errno_to_blk_status(ret);
7310
7311         ret = btrfs_check_dio_repairable(inode, failed_bio, failrec,
7312                                          failed_mirror);
7313         if (!ret) {
7314                 free_io_failure(failure_tree, io_tree, failrec);
7315                 return BLK_STS_IOERR;
7316         }
7317
7318         segs = bio_segments(failed_bio);
7319         bio_get_first_bvec(failed_bio, &bvec);
7320         if (segs > 1 ||
7321             (bvec.bv_len > btrfs_inode_sectorsize(inode)))
7322                 read_mode |= REQ_FAILFAST_DEV;
7323
7324         isector = start - btrfs_io_bio(failed_bio)->logical;
7325         isector >>= inode->i_sb->s_blocksize_bits;
7326         bio = btrfs_create_repair_bio(inode, failed_bio, failrec, page,
7327                                 pgoff, isector, repair_endio, repair_arg);
7328         bio->bi_opf = REQ_OP_READ | read_mode;
7329
7330         btrfs_debug(BTRFS_I(inode)->root->fs_info,
7331                     "repair DIO read error: submitting new dio read[%#x] to this_mirror=%d, in_validation=%d",
7332                     read_mode, failrec->this_mirror, failrec->in_validation);
7333
7334         status = submit_dio_repair_bio(inode, bio, failrec->this_mirror);
7335         if (status) {
7336                 free_io_failure(failure_tree, io_tree, failrec);
7337                 bio_put(bio);
7338         }
7339
7340         return status;
7341 }
7342
7343 struct btrfs_retry_complete {
7344         struct completion done;
7345         struct inode *inode;
7346         u64 start;
7347         int uptodate;
7348 };
7349
7350 static void btrfs_retry_endio_nocsum(struct bio *bio)
7351 {
7352         struct btrfs_retry_complete *done = bio->bi_private;
7353         struct inode *inode = done->inode;
7354         struct bio_vec *bvec;
7355         struct extent_io_tree *io_tree, *failure_tree;
7356         struct bvec_iter_all iter_all;
7357
7358         if (bio->bi_status)
7359                 goto end;
7360
7361         ASSERT(bio->bi_vcnt == 1);
7362         io_tree = &BTRFS_I(inode)->io_tree;
7363         failure_tree = &BTRFS_I(inode)->io_failure_tree;
7364         ASSERT(bio_first_bvec_all(bio)->bv_len == btrfs_inode_sectorsize(inode));
7365
7366         done->uptodate = 1;
7367         ASSERT(!bio_flagged(bio, BIO_CLONED));
7368         bio_for_each_segment_all(bvec, bio, iter_all)
7369                 clean_io_failure(BTRFS_I(inode)->root->fs_info, failure_tree,
7370                                  io_tree, done->start, bvec->bv_page,
7371                                  btrfs_ino(BTRFS_I(inode)), 0);
7372 end:
7373         complete(&done->done);
7374         bio_put(bio);
7375 }
7376
7377 static blk_status_t __btrfs_correct_data_nocsum(struct inode *inode,
7378                                                 struct btrfs_io_bio *io_bio)
7379 {
7380         struct btrfs_fs_info *fs_info;
7381         struct bio_vec bvec;
7382         struct bvec_iter iter;
7383         struct btrfs_retry_complete done;
7384         u64 start;
7385         unsigned int pgoff;
7386         u32 sectorsize;
7387         int nr_sectors;
7388         blk_status_t ret;
7389         blk_status_t err = BLK_STS_OK;
7390
7391         fs_info = BTRFS_I(inode)->root->fs_info;
7392         sectorsize = fs_info->sectorsize;
7393
7394         start = io_bio->logical;
7395         done.inode = inode;
7396         io_bio->bio.bi_iter = io_bio->iter;
7397
7398         bio_for_each_segment(bvec, &io_bio->bio, iter) {
7399                 nr_sectors = BTRFS_BYTES_TO_BLKS(fs_info, bvec.bv_len);
7400                 pgoff = bvec.bv_offset;
7401
7402 next_block_or_try_again:
7403                 done.uptodate = 0;
7404                 done.start = start;
7405                 init_completion(&done.done);
7406
7407                 ret = dio_read_error(inode, &io_bio->bio, bvec.bv_page,
7408                                 pgoff, start, start + sectorsize - 1,
7409                                 io_bio->mirror_num,
7410                                 btrfs_retry_endio_nocsum, &done);
7411                 if (ret) {
7412                         err = ret;
7413                         goto next;
7414                 }
7415
7416                 wait_for_completion_io(&done.done);
7417
7418                 if (!done.uptodate) {
7419                         /* We might have another mirror, so try again */
7420                         goto next_block_or_try_again;
7421                 }
7422
7423 next:
7424                 start += sectorsize;
7425
7426                 nr_sectors--;
7427                 if (nr_sectors) {
7428                         pgoff += sectorsize;
7429                         ASSERT(pgoff < PAGE_SIZE);
7430                         goto next_block_or_try_again;
7431                 }
7432         }
7433
7434         return err;
7435 }
7436
7437 static void btrfs_retry_endio(struct bio *bio)
7438 {
7439         struct btrfs_retry_complete *done = bio->bi_private;
7440         struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
7441         struct extent_io_tree *io_tree, *failure_tree;
7442         struct inode *inode = done->inode;
7443         struct bio_vec *bvec;
7444         int uptodate;
7445         int ret;
7446         int i = 0;
7447         struct bvec_iter_all iter_all;
7448
7449         if (bio->bi_status)
7450                 goto end;
7451
7452         uptodate = 1;
7453
7454         ASSERT(bio->bi_vcnt == 1);
7455         ASSERT(bio_first_bvec_all(bio)->bv_len == btrfs_inode_sectorsize(done->inode));
7456
7457         io_tree = &BTRFS_I(inode)->io_tree;
7458         failure_tree = &BTRFS_I(inode)->io_failure_tree;
7459
7460         ASSERT(!bio_flagged(bio, BIO_CLONED));
7461         bio_for_each_segment_all(bvec, bio, iter_all) {
7462                 ret = __readpage_endio_check(inode, io_bio, i, bvec->bv_page,
7463                                              bvec->bv_offset, done->start,
7464                                              bvec->bv_len);
7465                 if (!ret)
7466                         clean_io_failure(BTRFS_I(inode)->root->fs_info,
7467                                          failure_tree, io_tree, done->start,
7468                                          bvec->bv_page,
7469                                          btrfs_ino(BTRFS_I(inode)),
7470                                          bvec->bv_offset);
7471                 else
7472                         uptodate = 0;
7473                 i++;
7474         }
7475
7476         done->uptodate = uptodate;
7477 end:
7478         complete(&done->done);
7479         bio_put(bio);
7480 }
7481
7482 static blk_status_t __btrfs_subio_endio_read(struct inode *inode,
7483                 struct btrfs_io_bio *io_bio, blk_status_t err)
7484 {
7485         struct btrfs_fs_info *fs_info;
7486         struct bio_vec bvec;
7487         struct bvec_iter iter;
7488         struct btrfs_retry_complete done;
7489         u64 start;
7490         u64 offset = 0;
7491         u32 sectorsize;
7492         int nr_sectors;
7493         unsigned int pgoff;
7494         int csum_pos;
7495         bool uptodate = (err == 0);
7496         int ret;
7497         blk_status_t status;
7498
7499         fs_info = BTRFS_I(inode)->root->fs_info;
7500         sectorsize = fs_info->sectorsize;
7501
7502         err = BLK_STS_OK;
7503         start = io_bio->logical;
7504         done.inode = inode;
7505         io_bio->bio.bi_iter = io_bio->iter;
7506
7507         bio_for_each_segment(bvec, &io_bio->bio, iter) {
7508                 nr_sectors = BTRFS_BYTES_TO_BLKS(fs_info, bvec.bv_len);
7509
7510                 pgoff = bvec.bv_offset;
7511 next_block:
7512                 if (uptodate) {
7513                         csum_pos = BTRFS_BYTES_TO_BLKS(fs_info, offset);
7514                         ret = __readpage_endio_check(inode, io_bio, csum_pos,
7515                                         bvec.bv_page, pgoff, start, sectorsize);
7516                         if (likely(!ret))
7517                                 goto next;
7518                 }
7519 try_again:
7520                 done.uptodate = 0;
7521                 done.start = start;
7522                 init_completion(&done.done);
7523
7524                 status = dio_read_error(inode, &io_bio->bio, bvec.bv_page,
7525                                         pgoff, start, start + sectorsize - 1,
7526                                         io_bio->mirror_num, btrfs_retry_endio,
7527                                         &done);
7528                 if (status) {
7529                         err = status;
7530                         goto next;
7531                 }
7532
7533                 wait_for_completion_io(&done.done);
7534
7535                 if (!done.uptodate) {
7536                         /* We might have another mirror, so try again */
7537                         goto try_again;
7538                 }
7539 next:
7540                 offset += sectorsize;
7541                 start += sectorsize;
7542
7543                 ASSERT(nr_sectors);
7544
7545                 nr_sectors--;
7546                 if (nr_sectors) {
7547                         pgoff += sectorsize;
7548                         ASSERT(pgoff < PAGE_SIZE);
7549                         goto next_block;
7550                 }
7551         }
7552
7553         return err;
7554 }
7555
7556 static blk_status_t btrfs_subio_endio_read(struct inode *inode,
7557                 struct btrfs_io_bio *io_bio, blk_status_t err)
7558 {
7559         bool skip_csum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
7560
7561         if (skip_csum) {
7562                 if (unlikely(err))
7563                         return __btrfs_correct_data_nocsum(inode, io_bio);
7564                 else
7565                         return BLK_STS_OK;
7566         } else {
7567                 return __btrfs_subio_endio_read(inode, io_bio, err);
7568         }
7569 }
7570
7571 static void btrfs_endio_direct_read(struct bio *bio)
7572 {
7573         struct btrfs_dio_private *dip = bio->bi_private;
7574         struct inode *inode = dip->inode;
7575         struct bio *dio_bio;
7576         struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
7577         blk_status_t err = bio->bi_status;
7578
7579         if (dip->flags & BTRFS_DIO_ORIG_BIO_SUBMITTED)
7580                 err = btrfs_subio_endio_read(inode, io_bio, err);
7581
7582         unlock_extent(&BTRFS_I(inode)->io_tree, dip->logical_offset,
7583                       dip->logical_offset + dip->bytes - 1);
7584         dio_bio = dip->dio_bio;
7585
7586         kfree(dip);
7587
7588         dio_bio->bi_status = err;
7589         dio_end_io(dio_bio);
7590         btrfs_io_bio_free_csum(io_bio);
7591         bio_put(bio);
7592 }
7593
7594 static void __endio_write_update_ordered(struct inode *inode,
7595                                          const u64 offset, const u64 bytes,
7596                                          const bool uptodate)
7597 {
7598         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
7599         struct btrfs_ordered_extent *ordered = NULL;
7600         struct btrfs_workqueue *wq;
7601         u64 ordered_offset = offset;
7602         u64 ordered_bytes = bytes;
7603         u64 last_offset;
7604
7605         if (btrfs_is_free_space_inode(BTRFS_I(inode)))
7606                 wq = fs_info->endio_freespace_worker;
7607         else
7608                 wq = fs_info->endio_write_workers;
7609
7610         while (ordered_offset < offset + bytes) {
7611                 last_offset = ordered_offset;
7612                 if (btrfs_dec_test_first_ordered_pending(inode, &ordered,
7613                                                            &ordered_offset,
7614                                                            ordered_bytes,
7615                                                            uptodate)) {
7616                         btrfs_init_work(&ordered->work, finish_ordered_fn, NULL,
7617                                         NULL);
7618                         btrfs_queue_work(wq, &ordered->work);
7619                 }
7620                 /*
7621                  * If btrfs_dec_test_ordered_pending does not find any ordered
7622                  * extent in the range, we can exit.
7623                  */
7624                 if (ordered_offset == last_offset)
7625                         return;
7626                 /*
7627                  * Our bio might span multiple ordered extents. In this case
7628                  * we keep going until we have accounted the whole dio.
7629                  */
7630                 if (ordered_offset < offset + bytes) {
7631                         ordered_bytes = offset + bytes - ordered_offset;
7632                         ordered = NULL;
7633                 }
7634         }
7635 }
7636
7637 static void btrfs_endio_direct_write(struct bio *bio)
7638 {
7639         struct btrfs_dio_private *dip = bio->bi_private;
7640         struct bio *dio_bio = dip->dio_bio;
7641
7642         __endio_write_update_ordered(dip->inode, dip->logical_offset,
7643                                      dip->bytes, !bio->bi_status);
7644
7645         kfree(dip);
7646
7647         dio_bio->bi_status = bio->bi_status;
7648         dio_end_io(dio_bio);
7649         bio_put(bio);
7650 }
7651
7652 static blk_status_t btrfs_submit_bio_start_direct_io(void *private_data,
7653                                     struct bio *bio, u64 offset)
7654 {
7655         struct inode *inode = private_data;
7656         blk_status_t ret;
7657         ret = btrfs_csum_one_bio(inode, bio, offset, 1);
7658         BUG_ON(ret); /* -ENOMEM */
7659         return 0;
7660 }
7661
7662 static void btrfs_end_dio_bio(struct bio *bio)
7663 {
7664         struct btrfs_dio_private *dip = bio->bi_private;
7665         blk_status_t err = bio->bi_status;
7666
7667         if (err)
7668                 btrfs_warn(BTRFS_I(dip->inode)->root->fs_info,
7669                            "direct IO failed ino %llu rw %d,%u sector %#Lx len %u err no %d",
7670                            btrfs_ino(BTRFS_I(dip->inode)), bio_op(bio),
7671                            bio->bi_opf,
7672                            (unsigned long long)bio->bi_iter.bi_sector,
7673                            bio->bi_iter.bi_size, err);
7674
7675         if (dip->subio_endio)
7676                 err = dip->subio_endio(dip->inode, btrfs_io_bio(bio), err);
7677
7678         if (err) {
7679                 /*
7680                  * We want to perceive the errors flag being set before
7681                  * decrementing the reference count. We don't need a barrier
7682                  * since atomic operations with a return value are fully
7683                  * ordered as per atomic_t.txt
7684                  */
7685                 dip->errors = 1;
7686         }
7687
7688         /* if there are more bios still pending for this dio, just exit */
7689         if (!atomic_dec_and_test(&dip->pending_bios))
7690                 goto out;
7691
7692         if (dip->errors) {
7693                 bio_io_error(dip->orig_bio);
7694         } else {
7695                 dip->dio_bio->bi_status = BLK_STS_OK;
7696                 bio_endio(dip->orig_bio);
7697         }
7698 out:
7699         bio_put(bio);
7700 }
7701
7702 static inline blk_status_t btrfs_lookup_and_bind_dio_csum(struct inode *inode,
7703                                                  struct btrfs_dio_private *dip,
7704                                                  struct bio *bio,
7705                                                  u64 file_offset)
7706 {
7707         struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
7708         struct btrfs_io_bio *orig_io_bio = btrfs_io_bio(dip->orig_bio);
7709         blk_status_t ret;
7710
7711         /*
7712          * We load all the csum data we need when we submit
7713          * the first bio to reduce the csum tree search and
7714          * contention.
7715          */
7716         if (dip->logical_offset == file_offset) {
7717                 ret = btrfs_lookup_bio_sums(inode, dip->orig_bio, file_offset,
7718                                             NULL);
7719                 if (ret)
7720                         return ret;
7721         }
7722
7723         if (bio == dip->orig_bio)
7724                 return 0;
7725
7726         file_offset -= dip->logical_offset;
7727         file_offset >>= inode->i_sb->s_blocksize_bits;
7728         io_bio->csum = (u8 *)(((u32 *)orig_io_bio->csum) + file_offset);
7729
7730         return 0;
7731 }
7732
7733 static inline blk_status_t btrfs_submit_dio_bio(struct bio *bio,
7734                 struct inode *inode, u64 file_offset, int async_submit)
7735 {
7736         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
7737         struct btrfs_dio_private *dip = bio->bi_private;
7738         bool write = bio_op(bio) == REQ_OP_WRITE;
7739         blk_status_t ret;
7740
7741         /* Check btrfs_submit_bio_hook() for rules about async submit. */
7742         if (async_submit)
7743                 async_submit = !atomic_read(&BTRFS_I(inode)->sync_writers);
7744
7745         if (!write) {
7746                 ret = btrfs_bio_wq_end_io(fs_info, bio, BTRFS_WQ_ENDIO_DATA);
7747                 if (ret)
7748                         goto err;
7749         }
7750
7751         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)
7752                 goto map;
7753
7754         if (write && async_submit) {
7755                 ret = btrfs_wq_submit_bio(fs_info, bio, 0, 0,
7756                                           file_offset, inode,
7757                                           btrfs_submit_bio_start_direct_io);
7758                 goto err;
7759         } else if (write) {
7760                 /*
7761                  * If we aren't doing async submit, calculate the csum of the
7762                  * bio now.
7763                  */
7764                 ret = btrfs_csum_one_bio(inode, bio, file_offset, 1);
7765                 if (ret)
7766                         goto err;
7767         } else {
7768                 ret = btrfs_lookup_and_bind_dio_csum(inode, dip, bio,
7769                                                      file_offset);
7770                 if (ret)
7771                         goto err;
7772         }
7773 map:
7774         ret = btrfs_map_bio(fs_info, bio, 0);
7775 err:
7776         return ret;
7777 }
7778
7779 static int btrfs_submit_direct_hook(struct btrfs_dio_private *dip)
7780 {
7781         struct inode *inode = dip->inode;
7782         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
7783         struct bio *bio;
7784         struct bio *orig_bio = dip->orig_bio;
7785         u64 start_sector = orig_bio->bi_iter.bi_sector;
7786         u64 file_offset = dip->logical_offset;
7787         int async_submit = 0;
7788         u64 submit_len;
7789         int clone_offset = 0;
7790         int clone_len;
7791         int ret;
7792         blk_status_t status;
7793         struct btrfs_io_geometry geom;
7794
7795         submit_len = orig_bio->bi_iter.bi_size;
7796         ret = btrfs_get_io_geometry(fs_info, btrfs_op(orig_bio),
7797                                     start_sector << 9, submit_len, &geom);
7798         if (ret)
7799                 return -EIO;
7800
7801         if (geom.len >= submit_len) {
7802                 bio = orig_bio;
7803                 dip->flags |= BTRFS_DIO_ORIG_BIO_SUBMITTED;
7804                 goto submit;
7805         }
7806
7807         /* async crcs make it difficult to collect full stripe writes. */
7808         if (btrfs_data_alloc_profile(fs_info) & BTRFS_BLOCK_GROUP_RAID56_MASK)
7809                 async_submit = 0;
7810         else
7811                 async_submit = 1;
7812
7813         /* bio split */
7814         ASSERT(geom.len <= INT_MAX);
7815         atomic_inc(&dip->pending_bios);
7816         do {
7817                 clone_len = min_t(int, submit_len, geom.len);
7818
7819                 /*
7820                  * This will never fail as it's passing GPF_NOFS and
7821                  * the allocation is backed by btrfs_bioset.
7822                  */
7823                 bio = btrfs_bio_clone_partial(orig_bio, clone_offset,
7824                                               clone_len);
7825                 bio->bi_private = dip;
7826                 bio->bi_end_io = btrfs_end_dio_bio;
7827                 btrfs_io_bio(bio)->logical = file_offset;
7828
7829                 ASSERT(submit_len >= clone_len);
7830                 submit_len -= clone_len;
7831                 if (submit_len == 0)
7832                         break;
7833
7834                 /*
7835                  * Increase the count before we submit the bio so we know
7836                  * the end IO handler won't happen before we increase the
7837                  * count. Otherwise, the dip might get freed before we're
7838                  * done setting it up.
7839                  */
7840                 atomic_inc(&dip->pending_bios);
7841
7842                 status = btrfs_submit_dio_bio(bio, inode, file_offset,
7843                                                 async_submit);
7844                 if (status) {
7845                         bio_put(bio);
7846                         atomic_dec(&dip->pending_bios);
7847                         goto out_err;
7848                 }
7849
7850                 clone_offset += clone_len;
7851                 start_sector += clone_len >> 9;
7852                 file_offset += clone_len;
7853
7854                 ret = btrfs_get_io_geometry(fs_info, btrfs_op(orig_bio),
7855                                       start_sector << 9, submit_len, &geom);
7856                 if (ret)
7857                         goto out_err;
7858         } while (submit_len > 0);
7859
7860 submit:
7861         status = btrfs_submit_dio_bio(bio, inode, file_offset, async_submit);
7862         if (!status)
7863                 return 0;
7864
7865         bio_put(bio);
7866 out_err:
7867         dip->errors = 1;
7868         /*
7869          * Before atomic variable goto zero, we must  make sure dip->errors is
7870          * perceived to be set. This ordering is ensured by the fact that an
7871          * atomic operations with a return value are fully ordered as per
7872          * atomic_t.txt
7873          */
7874         if (atomic_dec_and_test(&dip->pending_bios))
7875                 bio_io_error(dip->orig_bio);
7876
7877         /* bio_end_io() will handle error, so we needn't return it */
7878         return 0;
7879 }
7880
7881 static void btrfs_submit_direct(struct bio *dio_bio, struct inode *inode,
7882                                 loff_t file_offset)
7883 {
7884         struct btrfs_dio_private *dip = NULL;
7885         struct bio *bio = NULL;
7886         struct btrfs_io_bio *io_bio;
7887         bool write = (bio_op(dio_bio) == REQ_OP_WRITE);
7888         int ret = 0;
7889
7890         bio = btrfs_bio_clone(dio_bio);
7891
7892         dip = kzalloc(sizeof(*dip), GFP_NOFS);
7893         if (!dip) {
7894                 ret = -ENOMEM;
7895                 goto free_ordered;
7896         }
7897
7898         dip->private = dio_bio->bi_private;
7899         dip->inode = inode;
7900         dip->logical_offset = file_offset;
7901         dip->bytes = dio_bio->bi_iter.bi_size;
7902         dip->disk_bytenr = (u64)dio_bio->bi_iter.bi_sector << 9;
7903         bio->bi_private = dip;
7904         dip->orig_bio = bio;
7905         dip->dio_bio = dio_bio;
7906         atomic_set(&dip->pending_bios, 0);
7907         io_bio = btrfs_io_bio(bio);
7908         io_bio->logical = file_offset;
7909
7910         if (write) {
7911                 bio->bi_end_io = btrfs_endio_direct_write;
7912         } else {
7913                 bio->bi_end_io = btrfs_endio_direct_read;
7914                 dip->subio_endio = btrfs_subio_endio_read;
7915         }
7916
7917         /*
7918          * Reset the range for unsubmitted ordered extents (to a 0 length range)
7919          * even if we fail to submit a bio, because in such case we do the
7920          * corresponding error handling below and it must not be done a second
7921          * time by btrfs_direct_IO().
7922          */
7923         if (write) {
7924                 struct btrfs_dio_data *dio_data = current->journal_info;
7925
7926                 dio_data->unsubmitted_oe_range_end = dip->logical_offset +
7927                         dip->bytes;
7928                 dio_data->unsubmitted_oe_range_start =
7929                         dio_data->unsubmitted_oe_range_end;
7930         }
7931
7932         ret = btrfs_submit_direct_hook(dip);
7933         if (!ret)
7934                 return;
7935
7936         btrfs_io_bio_free_csum(io_bio);
7937
7938 free_ordered:
7939         /*
7940          * If we arrived here it means either we failed to submit the dip
7941          * or we either failed to clone the dio_bio or failed to allocate the
7942          * dip. If we cloned the dio_bio and allocated the dip, we can just
7943          * call bio_endio against our io_bio so that we get proper resource
7944          * cleanup if we fail to submit the dip, otherwise, we must do the
7945          * same as btrfs_endio_direct_[write|read] because we can't call these
7946          * callbacks - they require an allocated dip and a clone of dio_bio.
7947          */
7948         if (bio && dip) {
7949                 bio_io_error(bio);
7950                 /*
7951                  * The end io callbacks free our dip, do the final put on bio
7952                  * and all the cleanup and final put for dio_bio (through
7953                  * dio_end_io()).
7954                  */
7955                 dip = NULL;
7956                 bio = NULL;
7957         } else {
7958                 if (write)
7959                         __endio_write_update_ordered(inode,
7960                                                 file_offset,
7961                                                 dio_bio->bi_iter.bi_size,
7962                                                 false);
7963                 else
7964                         unlock_extent(&BTRFS_I(inode)->io_tree, file_offset,
7965                               file_offset + dio_bio->bi_iter.bi_size - 1);
7966
7967                 dio_bio->bi_status = BLK_STS_IOERR;
7968                 /*
7969                  * Releases and cleans up our dio_bio, no need to bio_put()
7970                  * nor bio_endio()/bio_io_error() against dio_bio.
7971                  */
7972                 dio_end_io(dio_bio);
7973         }
7974         if (bio)
7975                 bio_put(bio);
7976         kfree(dip);
7977 }
7978
7979 static ssize_t check_direct_IO(struct btrfs_fs_info *fs_info,
7980                                const struct iov_iter *iter, loff_t offset)
7981 {
7982         int seg;
7983         int i;
7984         unsigned int blocksize_mask = fs_info->sectorsize - 1;
7985         ssize_t retval = -EINVAL;
7986
7987         if (offset & blocksize_mask)
7988                 goto out;
7989
7990         if (iov_iter_alignment(iter) & blocksize_mask)
7991                 goto out;
7992
7993         /* If this is a write we don't need to check anymore */
7994         if (iov_iter_rw(iter) != READ || !iter_is_iovec(iter))
7995                 return 0;
7996         /*
7997          * Check to make sure we don't have duplicate iov_base's in this
7998          * iovec, if so return EINVAL, otherwise we'll get csum errors
7999          * when reading back.
8000          */
8001         for (seg = 0; seg < iter->nr_segs; seg++) {
8002                 for (i = seg + 1; i < iter->nr_segs; i++) {
8003                         if (iter->iov[seg].iov_base == iter->iov[i].iov_base)
8004                                 goto out;
8005                 }
8006         }
8007         retval = 0;
8008 out:
8009         return retval;
8010 }
8011
8012 static ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
8013 {
8014         struct file *file = iocb->ki_filp;
8015         struct inode *inode = file->f_mapping->host;
8016         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
8017         struct btrfs_dio_data dio_data = { 0 };
8018         struct extent_changeset *data_reserved = NULL;
8019         loff_t offset = iocb->ki_pos;
8020         size_t count = 0;
8021         int flags = 0;
8022         bool wakeup = true;
8023         bool relock = false;
8024         ssize_t ret;
8025
8026         if (check_direct_IO(fs_info, iter, offset))
8027                 return 0;
8028
8029         inode_dio_begin(inode);
8030
8031         /*
8032          * The generic stuff only does filemap_write_and_wait_range, which
8033          * isn't enough if we've written compressed pages to this area, so
8034          * we need to flush the dirty pages again to make absolutely sure
8035          * that any outstanding dirty pages are on disk.
8036          */
8037         count = iov_iter_count(iter);
8038         if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
8039                      &BTRFS_I(inode)->runtime_flags))
8040                 filemap_fdatawrite_range(inode->i_mapping, offset,
8041                                          offset + count - 1);
8042
8043         if (iov_iter_rw(iter) == WRITE) {
8044                 /*
8045                  * If the write DIO is beyond the EOF, we need update
8046                  * the isize, but it is protected by i_mutex. So we can
8047                  * not unlock the i_mutex at this case.
8048                  */
8049                 if (offset + count <= inode->i_size) {
8050                         dio_data.overwrite = 1;
8051                         inode_unlock(inode);
8052                         relock = true;
8053                 } else if (iocb->ki_flags & IOCB_NOWAIT) {
8054                         ret = -EAGAIN;
8055                         goto out;
8056                 }
8057                 ret = btrfs_delalloc_reserve_space(inode, &data_reserved,
8058                                                    offset, count);
8059                 if (ret)
8060                         goto out;
8061
8062                 /*
8063                  * We need to know how many extents we reserved so that we can
8064                  * do the accounting properly if we go over the number we
8065                  * originally calculated.  Abuse current->journal_info for this.
8066                  */
8067                 dio_data.reserve = round_up(count,
8068                                             fs_info->sectorsize);
8069                 dio_data.unsubmitted_oe_range_start = (u64)offset;
8070                 dio_data.unsubmitted_oe_range_end = (u64)offset;
8071                 current->journal_info = &dio_data;
8072                 down_read(&BTRFS_I(inode)->dio_sem);
8073         } else if (test_bit(BTRFS_INODE_READDIO_NEED_LOCK,
8074                                      &BTRFS_I(inode)->runtime_flags)) {
8075                 inode_dio_end(inode);
8076                 flags = DIO_LOCKING | DIO_SKIP_HOLES;
8077                 wakeup = false;
8078         }
8079
8080         ret = __blockdev_direct_IO(iocb, inode,
8081                                    fs_info->fs_devices->latest_bdev,
8082                                    iter, btrfs_get_blocks_direct, NULL,
8083                                    btrfs_submit_direct, flags);
8084         if (iov_iter_rw(iter) == WRITE) {
8085                 up_read(&BTRFS_I(inode)->dio_sem);
8086                 current->journal_info = NULL;
8087                 if (ret < 0 && ret != -EIOCBQUEUED) {
8088                         if (dio_data.reserve)
8089                                 btrfs_delalloc_release_space(inode, data_reserved,
8090                                         offset, dio_data.reserve, true);
8091                         /*
8092                          * On error we might have left some ordered extents
8093                          * without submitting corresponding bios for them, so
8094                          * cleanup them up to avoid other tasks getting them
8095                          * and waiting for them to complete forever.
8096                          */
8097                         if (dio_data.unsubmitted_oe_range_start <
8098                             dio_data.unsubmitted_oe_range_end)
8099                                 __endio_write_update_ordered(inode,
8100                                         dio_data.unsubmitted_oe_range_start,
8101                                         dio_data.unsubmitted_oe_range_end -
8102                                         dio_data.unsubmitted_oe_range_start,
8103                                         false);
8104                 } else if (ret >= 0 && (size_t)ret < count)
8105                         btrfs_delalloc_release_space(inode, data_reserved,
8106                                         offset, count - (size_t)ret, true);
8107                 btrfs_delalloc_release_extents(BTRFS_I(inode), count);
8108         }
8109 out:
8110         if (wakeup)
8111                 inode_dio_end(inode);
8112         if (relock)
8113                 inode_lock(inode);
8114
8115         extent_changeset_free(data_reserved);
8116         return ret;
8117 }
8118
8119 #define BTRFS_FIEMAP_FLAGS      (FIEMAP_FLAG_SYNC)
8120
8121 static int btrfs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
8122                 __u64 start, __u64 len)
8123 {
8124         int     ret;
8125
8126         ret = fiemap_check_flags(fieinfo, BTRFS_FIEMAP_FLAGS);
8127         if (ret)
8128                 return ret;
8129
8130         return extent_fiemap(inode, fieinfo, start, len);
8131 }
8132
8133 int btrfs_readpage(struct file *file, struct page *page)
8134 {
8135         struct extent_io_tree *tree;
8136         tree = &BTRFS_I(page->mapping->host)->io_tree;
8137         return extent_read_full_page(tree, page, btrfs_get_extent, 0);
8138 }
8139
8140 static int btrfs_writepage(struct page *page, struct writeback_control *wbc)
8141 {
8142         struct inode *inode = page->mapping->host;
8143         int ret;
8144
8145         if (current->flags & PF_MEMALLOC) {
8146                 redirty_page_for_writepage(wbc, page);
8147                 unlock_page(page);
8148                 return 0;
8149         }
8150
8151         /*
8152          * If we are under memory pressure we will call this directly from the
8153          * VM, we need to make sure we have the inode referenced for the ordered
8154          * extent.  If not just return like we didn't do anything.
8155          */
8156         if (!igrab(inode)) {
8157                 redirty_page_for_writepage(wbc, page);
8158                 return AOP_WRITEPAGE_ACTIVATE;
8159         }
8160         ret = extent_write_full_page(page, wbc);
8161         btrfs_add_delayed_iput(inode);
8162         return ret;
8163 }
8164
8165 static int btrfs_writepages(struct address_space *mapping,
8166                             struct writeback_control *wbc)
8167 {
8168         return extent_writepages(mapping, wbc);
8169 }
8170
8171 static int
8172 btrfs_readpages(struct file *file, struct address_space *mapping,
8173                 struct list_head *pages, unsigned nr_pages)
8174 {
8175         return extent_readpages(mapping, pages, nr_pages);
8176 }
8177
8178 static int __btrfs_releasepage(struct page *page, gfp_t gfp_flags)
8179 {
8180         int ret = try_release_extent_mapping(page, gfp_flags);
8181         if (ret == 1) {
8182                 ClearPagePrivate(page);
8183                 set_page_private(page, 0);
8184                 put_page(page);
8185         }
8186         return ret;
8187 }
8188
8189 static int btrfs_releasepage(struct page *page, gfp_t gfp_flags)
8190 {
8191         if (PageWriteback(page) || PageDirty(page))
8192                 return 0;
8193         return __btrfs_releasepage(page, gfp_flags);
8194 }
8195
8196 static void btrfs_invalidatepage(struct page *page, unsigned int offset,
8197                                  unsigned int length)
8198 {
8199         struct inode *inode = page->mapping->host;
8200         struct extent_io_tree *tree;
8201         struct btrfs_ordered_extent *ordered;
8202         struct extent_state *cached_state = NULL;
8203         u64 page_start = page_offset(page);
8204         u64 page_end = page_start + PAGE_SIZE - 1;
8205         u64 start;
8206         u64 end;
8207         int inode_evicting = inode->i_state & I_FREEING;
8208
8209         /*
8210          * we have the page locked, so new writeback can't start,
8211          * and the dirty bit won't be cleared while we are here.
8212          *
8213          * Wait for IO on this page so that we can safely clear
8214          * the PagePrivate2 bit and do ordered accounting
8215          */
8216         wait_on_page_writeback(page);
8217
8218         tree = &BTRFS_I(inode)->io_tree;
8219         if (offset) {
8220                 btrfs_releasepage(page, GFP_NOFS);
8221                 return;
8222         }
8223
8224         if (!inode_evicting)
8225                 lock_extent_bits(tree, page_start, page_end, &cached_state);
8226 again:
8227         start = page_start;
8228         ordered = btrfs_lookup_ordered_range(BTRFS_I(inode), start,
8229                                         page_end - start + 1);
8230         if (ordered) {
8231                 end = min(page_end,
8232                           ordered->file_offset + ordered->num_bytes - 1);
8233                 /*
8234                  * IO on this page will never be started, so we need
8235                  * to account for any ordered extents now
8236                  */
8237                 if (!inode_evicting)
8238                         clear_extent_bit(tree, start, end,
8239                                          EXTENT_DELALLOC | EXTENT_DELALLOC_NEW |
8240                                          EXTENT_LOCKED | EXTENT_DO_ACCOUNTING |
8241                                          EXTENT_DEFRAG, 1, 0, &cached_state);
8242                 /*
8243                  * whoever cleared the private bit is responsible
8244                  * for the finish_ordered_io
8245                  */
8246                 if (TestClearPagePrivate2(page)) {
8247                         struct btrfs_ordered_inode_tree *tree;
8248                         u64 new_len;
8249
8250                         tree = &BTRFS_I(inode)->ordered_tree;
8251
8252                         spin_lock_irq(&tree->lock);
8253                         set_bit(BTRFS_ORDERED_TRUNCATED, &ordered->flags);
8254                         new_len = start - ordered->file_offset;
8255                         if (new_len < ordered->truncated_len)
8256                                 ordered->truncated_len = new_len;
8257                         spin_unlock_irq(&tree->lock);
8258
8259                         if (btrfs_dec_test_ordered_pending(inode, &ordered,
8260                                                            start,
8261                                                            end - start + 1, 1))
8262                                 btrfs_finish_ordered_io(ordered);
8263                 }
8264                 btrfs_put_ordered_extent(ordered);
8265                 if (!inode_evicting) {
8266                         cached_state = NULL;
8267                         lock_extent_bits(tree, start, end,
8268                                          &cached_state);
8269                 }
8270
8271                 start = end + 1;
8272                 if (start < page_end)
8273                         goto again;
8274         }
8275
8276         /*
8277          * Qgroup reserved space handler
8278          * Page here will be either
8279          * 1) Already written to disk
8280          *    In this case, its reserved space is released from data rsv map
8281          *    and will be freed by delayed_ref handler finally.
8282          *    So even we call qgroup_free_data(), it won't decrease reserved
8283          *    space.
8284          * 2) Not written to disk
8285          *    This means the reserved space should be freed here. However,
8286          *    if a truncate invalidates the page (by clearing PageDirty)
8287          *    and the page is accounted for while allocating extent
8288          *    in btrfs_check_data_free_space() we let delayed_ref to
8289          *    free the entire extent.
8290          */
8291         if (PageDirty(page))
8292                 btrfs_qgroup_free_data(inode, NULL, page_start, PAGE_SIZE);
8293         if (!inode_evicting) {
8294                 clear_extent_bit(tree, page_start, page_end, EXTENT_LOCKED |
8295                                  EXTENT_DELALLOC | EXTENT_DELALLOC_NEW |
8296                                  EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG, 1, 1,
8297                                  &cached_state);
8298
8299                 __btrfs_releasepage(page, GFP_NOFS);
8300         }
8301
8302         ClearPageChecked(page);
8303         if (PagePrivate(page)) {
8304                 ClearPagePrivate(page);
8305                 set_page_private(page, 0);
8306                 put_page(page);
8307         }
8308 }
8309
8310 /*
8311  * btrfs_page_mkwrite() is not allowed to change the file size as it gets
8312  * called from a page fault handler when a page is first dirtied. Hence we must
8313  * be careful to check for EOF conditions here. We set the page up correctly
8314  * for a written page which means we get ENOSPC checking when writing into
8315  * holes and correct delalloc and unwritten extent mapping on filesystems that
8316  * support these features.
8317  *
8318  * We are not allowed to take the i_mutex here so we have to play games to
8319  * protect against truncate races as the page could now be beyond EOF.  Because
8320  * truncate_setsize() writes the inode size before removing pages, once we have
8321  * the page lock we can determine safely if the page is beyond EOF. If it is not
8322  * beyond EOF, then the page is guaranteed safe against truncation until we
8323  * unlock the page.
8324  */
8325 vm_fault_t btrfs_page_mkwrite(struct vm_fault *vmf)
8326 {
8327         struct page *page = vmf->page;
8328         struct inode *inode = file_inode(vmf->vma->vm_file);
8329         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
8330         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
8331         struct btrfs_ordered_extent *ordered;
8332         struct extent_state *cached_state = NULL;
8333         struct extent_changeset *data_reserved = NULL;
8334         char *kaddr;
8335         unsigned long zero_start;
8336         loff_t size;
8337         vm_fault_t ret;
8338         int ret2;
8339         int reserved = 0;
8340         u64 reserved_space;
8341         u64 page_start;
8342         u64 page_end;
8343         u64 end;
8344
8345         reserved_space = PAGE_SIZE;
8346
8347         sb_start_pagefault(inode->i_sb);
8348         page_start = page_offset(page);
8349         page_end = page_start + PAGE_SIZE - 1;
8350         end = page_end;
8351
8352         /*
8353          * Reserving delalloc space after obtaining the page lock can lead to
8354          * deadlock. For example, if a dirty page is locked by this function
8355          * and the call to btrfs_delalloc_reserve_space() ends up triggering
8356          * dirty page write out, then the btrfs_writepage() function could
8357          * end up waiting indefinitely to get a lock on the page currently
8358          * being processed by btrfs_page_mkwrite() function.
8359          */
8360         ret2 = btrfs_delalloc_reserve_space(inode, &data_reserved, page_start,
8361                                            reserved_space);
8362         if (!ret2) {
8363                 ret2 = file_update_time(vmf->vma->vm_file);
8364                 reserved = 1;
8365         }
8366         if (ret2) {
8367                 ret = vmf_error(ret2);
8368                 if (reserved)
8369                         goto out;
8370                 goto out_noreserve;
8371         }
8372
8373         ret = VM_FAULT_NOPAGE; /* make the VM retry the fault */
8374 again:
8375         lock_page(page);
8376         size = i_size_read(inode);
8377
8378         if ((page->mapping != inode->i_mapping) ||
8379             (page_start >= size)) {
8380                 /* page got truncated out from underneath us */
8381                 goto out_unlock;
8382         }
8383         wait_on_page_writeback(page);
8384
8385         lock_extent_bits(io_tree, page_start, page_end, &cached_state);
8386         set_page_extent_mapped(page);
8387
8388         /*
8389          * we can't set the delalloc bits if there are pending ordered
8390          * extents.  Drop our locks and wait for them to finish
8391          */
8392         ordered = btrfs_lookup_ordered_range(BTRFS_I(inode), page_start,
8393                         PAGE_SIZE);
8394         if (ordered) {
8395                 unlock_extent_cached(io_tree, page_start, page_end,
8396                                      &cached_state);
8397                 unlock_page(page);
8398                 btrfs_start_ordered_extent(inode, ordered, 1);
8399                 btrfs_put_ordered_extent(ordered);
8400                 goto again;
8401         }
8402
8403         if (page->index == ((size - 1) >> PAGE_SHIFT)) {
8404                 reserved_space = round_up(size - page_start,
8405                                           fs_info->sectorsize);
8406                 if (reserved_space < PAGE_SIZE) {
8407                         end = page_start + reserved_space - 1;
8408                         btrfs_delalloc_release_space(inode, data_reserved,
8409                                         page_start, PAGE_SIZE - reserved_space,
8410                                         true);
8411                 }
8412         }
8413
8414         /*
8415          * page_mkwrite gets called when the page is firstly dirtied after it's
8416          * faulted in, but write(2) could also dirty a page and set delalloc
8417          * bits, thus in this case for space account reason, we still need to
8418          * clear any delalloc bits within this page range since we have to
8419          * reserve data&meta space before lock_page() (see above comments).
8420          */
8421         clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start, end,
8422                           EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING |
8423                           EXTENT_DEFRAG, 0, 0, &cached_state);
8424
8425         ret2 = btrfs_set_extent_delalloc(inode, page_start, end, 0,
8426                                         &cached_state);
8427         if (ret2) {
8428                 unlock_extent_cached(io_tree, page_start, page_end,
8429                                      &cached_state);
8430                 ret = VM_FAULT_SIGBUS;
8431                 goto out_unlock;
8432         }
8433
8434         /* page is wholly or partially inside EOF */
8435         if (page_start + PAGE_SIZE > size)
8436                 zero_start = offset_in_page(size);
8437         else
8438                 zero_start = PAGE_SIZE;
8439
8440         if (zero_start != PAGE_SIZE) {
8441                 kaddr = kmap(page);
8442                 memset(kaddr + zero_start, 0, PAGE_SIZE - zero_start);
8443                 flush_dcache_page(page);
8444                 kunmap(page);
8445         }
8446         ClearPageChecked(page);
8447         set_page_dirty(page);
8448         SetPageUptodate(page);
8449
8450         BTRFS_I(inode)->last_trans = fs_info->generation;
8451         BTRFS_I(inode)->last_sub_trans = BTRFS_I(inode)->root->log_transid;
8452         BTRFS_I(inode)->last_log_commit = BTRFS_I(inode)->root->last_log_commit;
8453
8454         unlock_extent_cached(io_tree, page_start, page_end, &cached_state);
8455
8456         btrfs_delalloc_release_extents(BTRFS_I(inode), PAGE_SIZE);
8457         sb_end_pagefault(inode->i_sb);
8458         extent_changeset_free(data_reserved);
8459         return VM_FAULT_LOCKED;
8460
8461 out_unlock:
8462         unlock_page(page);
8463 out:
8464         btrfs_delalloc_release_extents(BTRFS_I(inode), PAGE_SIZE);
8465         btrfs_delalloc_release_space(inode, data_reserved, page_start,
8466                                      reserved_space, (ret != 0));
8467 out_noreserve:
8468         sb_end_pagefault(inode->i_sb);
8469         extent_changeset_free(data_reserved);
8470         return ret;
8471 }
8472
8473 static int btrfs_truncate(struct inode *inode, bool skip_writeback)
8474 {
8475         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
8476         struct btrfs_root *root = BTRFS_I(inode)->root;
8477         struct btrfs_block_rsv *rsv;
8478         int ret;
8479         struct btrfs_trans_handle *trans;
8480         u64 mask = fs_info->sectorsize - 1;
8481         u64 min_size = btrfs_calc_metadata_size(fs_info, 1);
8482
8483         if (!skip_writeback) {
8484                 ret = btrfs_wait_ordered_range(inode, inode->i_size & (~mask),
8485                                                (u64)-1);
8486                 if (ret)
8487                         return ret;
8488         }
8489
8490         /*
8491          * Yes ladies and gentlemen, this is indeed ugly.  We have a couple of
8492          * things going on here:
8493          *
8494          * 1) We need to reserve space to update our inode.
8495          *
8496          * 2) We need to have something to cache all the space that is going to
8497          * be free'd up by the truncate operation, but also have some slack
8498          * space reserved in case it uses space during the truncate (thank you
8499          * very much snapshotting).
8500          *
8501          * And we need these to be separate.  The fact is we can use a lot of
8502          * space doing the truncate, and we have no earthly idea how much space
8503          * we will use, so we need the truncate reservation to be separate so it
8504          * doesn't end up using space reserved for updating the inode.  We also
8505          * need to be able to stop the transaction and start a new one, which
8506          * means we need to be able to update the inode several times, and we
8507          * have no idea of knowing how many times that will be, so we can't just
8508          * reserve 1 item for the entirety of the operation, so that has to be
8509          * done separately as well.
8510          *
8511          * So that leaves us with
8512          *
8513          * 1) rsv - for the truncate reservation, which we will steal from the
8514          * transaction reservation.
8515          * 2) fs_info->trans_block_rsv - this will have 1 items worth left for
8516          * updating the inode.
8517          */
8518         rsv = btrfs_alloc_block_rsv(fs_info, BTRFS_BLOCK_RSV_TEMP);
8519         if (!rsv)
8520                 return -ENOMEM;
8521         rsv->size = min_size;
8522         rsv->failfast = 1;
8523
8524         /*
8525          * 1 for the truncate slack space
8526          * 1 for updating the inode.
8527          */
8528         trans = btrfs_start_transaction(root, 2);
8529         if (IS_ERR(trans)) {
8530                 ret = PTR_ERR(trans);
8531                 goto out;
8532         }
8533
8534         /* Migrate the slack space for the truncate to our reserve */
8535         ret = btrfs_block_rsv_migrate(&fs_info->trans_block_rsv, rsv,
8536                                       min_size, false);
8537         BUG_ON(ret);
8538
8539         /*
8540          * So if we truncate and then write and fsync we normally would just
8541          * write the extents that changed, which is a problem if we need to
8542          * first truncate that entire inode.  So set this flag so we write out
8543          * all of the extents in the inode to the sync log so we're completely
8544          * safe.
8545          */
8546         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
8547         trans->block_rsv = rsv;
8548
8549         while (1) {
8550                 ret = btrfs_truncate_inode_items(trans, root, inode,
8551                                                  inode->i_size,
8552                                                  BTRFS_EXTENT_DATA_KEY);
8553                 trans->block_rsv = &fs_info->trans_block_rsv;
8554                 if (ret != -ENOSPC && ret != -EAGAIN)
8555                         break;
8556
8557                 ret = btrfs_update_inode(trans, root, inode);
8558                 if (ret)
8559                         break;
8560
8561                 btrfs_end_transaction(trans);
8562                 btrfs_btree_balance_dirty(fs_info);
8563
8564                 trans = btrfs_start_transaction(root, 2);
8565                 if (IS_ERR(trans)) {
8566                         ret = PTR_ERR(trans);
8567                         trans = NULL;
8568                         break;
8569                 }
8570
8571                 btrfs_block_rsv_release(fs_info, rsv, -1);
8572                 ret = btrfs_block_rsv_migrate(&fs_info->trans_block_rsv,
8573                                               rsv, min_size, false);
8574                 BUG_ON(ret);    /* shouldn't happen */
8575                 trans->block_rsv = rsv;
8576         }
8577
8578         /*
8579          * We can't call btrfs_truncate_block inside a trans handle as we could
8580          * deadlock with freeze, if we got NEED_TRUNCATE_BLOCK then we know
8581          * we've truncated everything except the last little bit, and can do
8582          * btrfs_truncate_block and then update the disk_i_size.
8583          */
8584         if (ret == NEED_TRUNCATE_BLOCK) {
8585                 btrfs_end_transaction(trans);
8586                 btrfs_btree_balance_dirty(fs_info);
8587
8588                 ret = btrfs_truncate_block(inode, inode->i_size, 0, 0);
8589                 if (ret)
8590                         goto out;
8591                 trans = btrfs_start_transaction(root, 1);
8592                 if (IS_ERR(trans)) {
8593                         ret = PTR_ERR(trans);
8594                         goto out;
8595                 }
8596                 btrfs_ordered_update_i_size(inode, inode->i_size, NULL);
8597         }
8598
8599         if (trans) {
8600                 int ret2;
8601
8602                 trans->block_rsv = &fs_info->trans_block_rsv;
8603                 ret2 = btrfs_update_inode(trans, root, inode);
8604                 if (ret2 && !ret)
8605                         ret = ret2;
8606
8607                 ret2 = btrfs_end_transaction(trans);
8608                 if (ret2 && !ret)
8609                         ret = ret2;
8610                 btrfs_btree_balance_dirty(fs_info);
8611         }
8612 out:
8613         btrfs_free_block_rsv(fs_info, rsv);
8614
8615         return ret;
8616 }
8617
8618 /*
8619  * create a new subvolume directory/inode (helper for the ioctl).
8620  */
8621 int btrfs_create_subvol_root(struct btrfs_trans_handle *trans,
8622                              struct btrfs_root *new_root,
8623                              struct btrfs_root *parent_root,
8624                              u64 new_dirid)
8625 {
8626         struct inode *inode;
8627         int err;
8628         u64 index = 0;
8629
8630         inode = btrfs_new_inode(trans, new_root, NULL, "..", 2,
8631                                 new_dirid, new_dirid,
8632                                 S_IFDIR | (~current_umask() & S_IRWXUGO),
8633                                 &index);
8634         if (IS_ERR(inode))
8635                 return PTR_ERR(inode);
8636         inode->i_op = &btrfs_dir_inode_operations;
8637         inode->i_fop = &btrfs_dir_file_operations;
8638
8639         set_nlink(inode, 1);
8640         btrfs_i_size_write(BTRFS_I(inode), 0);
8641         unlock_new_inode(inode);
8642
8643         err = btrfs_subvol_inherit_props(trans, new_root, parent_root);
8644         if (err)
8645                 btrfs_err(new_root->fs_info,
8646                           "error inheriting subvolume %llu properties: %d",
8647                           new_root->root_key.objectid, err);
8648
8649         err = btrfs_update_inode(trans, new_root, inode);
8650
8651         iput(inode);
8652         return err;
8653 }
8654
8655 struct inode *btrfs_alloc_inode(struct super_block *sb)
8656 {
8657         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
8658         struct btrfs_inode *ei;
8659         struct inode *inode;
8660
8661         ei = kmem_cache_alloc(btrfs_inode_cachep, GFP_KERNEL);
8662         if (!ei)
8663                 return NULL;
8664
8665         ei->root = NULL;
8666         ei->generation = 0;
8667         ei->last_trans = 0;
8668         ei->last_sub_trans = 0;
8669         ei->logged_trans = 0;
8670         ei->delalloc_bytes = 0;
8671         ei->new_delalloc_bytes = 0;
8672         ei->defrag_bytes = 0;
8673         ei->disk_i_size = 0;
8674         ei->flags = 0;
8675         ei->csum_bytes = 0;
8676         ei->index_cnt = (u64)-1;
8677         ei->dir_index = 0;
8678         ei->last_unlink_trans = 0;
8679         ei->last_log_commit = 0;
8680
8681         spin_lock_init(&ei->lock);
8682         ei->outstanding_extents = 0;
8683         if (sb->s_magic != BTRFS_TEST_MAGIC)
8684                 btrfs_init_metadata_block_rsv(fs_info, &ei->block_rsv,
8685                                               BTRFS_BLOCK_RSV_DELALLOC);
8686         ei->runtime_flags = 0;
8687         ei->prop_compress = BTRFS_COMPRESS_NONE;
8688         ei->defrag_compress = BTRFS_COMPRESS_NONE;
8689
8690         ei->delayed_node = NULL;
8691
8692         ei->i_otime.tv_sec = 0;
8693         ei->i_otime.tv_nsec = 0;
8694
8695         inode = &ei->vfs_inode;
8696         extent_map_tree_init(&ei->extent_tree);
8697         extent_io_tree_init(fs_info, &ei->io_tree, IO_TREE_INODE_IO, inode);
8698         extent_io_tree_init(fs_info, &ei->io_failure_tree,
8699                             IO_TREE_INODE_IO_FAILURE, inode);
8700         ei->io_tree.track_uptodate = true;
8701         ei->io_failure_tree.track_uptodate = true;
8702         atomic_set(&ei->sync_writers, 0);
8703         mutex_init(&ei->log_mutex);
8704         btrfs_ordered_inode_tree_init(&ei->ordered_tree);
8705         INIT_LIST_HEAD(&ei->delalloc_inodes);
8706         INIT_LIST_HEAD(&ei->delayed_iput);
8707         RB_CLEAR_NODE(&ei->rb_node);
8708         init_rwsem(&ei->dio_sem);
8709
8710         return inode;
8711 }
8712
8713 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
8714 void btrfs_test_destroy_inode(struct inode *inode)
8715 {
8716         btrfs_drop_extent_cache(BTRFS_I(inode), 0, (u64)-1, 0);
8717         kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
8718 }
8719 #endif
8720
8721 void btrfs_free_inode(struct inode *inode)
8722 {
8723         kmem_cache_free(btrfs_inode_cachep, BTRFS_I(inode));
8724 }
8725
8726 void btrfs_destroy_inode(struct inode *inode)
8727 {
8728         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
8729         struct btrfs_ordered_extent *ordered;
8730         struct btrfs_root *root = BTRFS_I(inode)->root;
8731
8732         WARN_ON(!hlist_empty(&inode->i_dentry));
8733         WARN_ON(inode->i_data.nrpages);
8734         WARN_ON(BTRFS_I(inode)->block_rsv.reserved);
8735         WARN_ON(BTRFS_I(inode)->block_rsv.size);
8736         WARN_ON(BTRFS_I(inode)->outstanding_extents);
8737         WARN_ON(BTRFS_I(inode)->delalloc_bytes);
8738         WARN_ON(BTRFS_I(inode)->new_delalloc_bytes);
8739         WARN_ON(BTRFS_I(inode)->csum_bytes);
8740         WARN_ON(BTRFS_I(inode)->defrag_bytes);
8741
8742         /*
8743          * This can happen where we create an inode, but somebody else also
8744          * created the same inode and we need to destroy the one we already
8745          * created.
8746          */
8747         if (!root)
8748                 return;
8749
8750         while (1) {
8751                 ordered = btrfs_lookup_first_ordered_extent(inode, (u64)-1);
8752                 if (!ordered)
8753                         break;
8754                 else {
8755                         btrfs_err(fs_info,
8756                                   "found ordered extent %llu %llu on inode cleanup",
8757                                   ordered->file_offset, ordered->num_bytes);
8758                         btrfs_remove_ordered_extent(inode, ordered);
8759                         btrfs_put_ordered_extent(ordered);
8760                         btrfs_put_ordered_extent(ordered);
8761                 }
8762         }
8763         btrfs_qgroup_check_reserved_leak(inode);
8764         inode_tree_del(inode);
8765         btrfs_drop_extent_cache(BTRFS_I(inode), 0, (u64)-1, 0);
8766 }
8767
8768 int btrfs_drop_inode(struct inode *inode)
8769 {
8770         struct btrfs_root *root = BTRFS_I(inode)->root;
8771
8772         if (root == NULL)
8773                 return 1;
8774
8775         /* the snap/subvol tree is on deleting */
8776         if (btrfs_root_refs(&root->root_item) == 0)
8777                 return 1;
8778         else
8779                 return generic_drop_inode(inode);
8780 }
8781
8782 static void init_once(void *foo)
8783 {
8784         struct btrfs_inode *ei = (struct btrfs_inode *) foo;
8785
8786         inode_init_once(&ei->vfs_inode);
8787 }
8788
8789 void __cold btrfs_destroy_cachep(void)
8790 {
8791         /*
8792          * Make sure all delayed rcu free inodes are flushed before we
8793          * destroy cache.
8794          */
8795         rcu_barrier();
8796         kmem_cache_destroy(btrfs_inode_cachep);
8797         kmem_cache_destroy(btrfs_trans_handle_cachep);
8798         kmem_cache_destroy(btrfs_path_cachep);
8799         kmem_cache_destroy(btrfs_free_space_cachep);
8800         kmem_cache_destroy(btrfs_free_space_bitmap_cachep);
8801 }
8802
8803 int __init btrfs_init_cachep(void)
8804 {
8805         btrfs_inode_cachep = kmem_cache_create("btrfs_inode",
8806                         sizeof(struct btrfs_inode), 0,
8807                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD | SLAB_ACCOUNT,
8808                         init_once);
8809         if (!btrfs_inode_cachep)
8810                 goto fail;
8811
8812         btrfs_trans_handle_cachep = kmem_cache_create("btrfs_trans_handle",
8813                         sizeof(struct btrfs_trans_handle), 0,
8814                         SLAB_TEMPORARY | SLAB_MEM_SPREAD, NULL);
8815         if (!btrfs_trans_handle_cachep)
8816                 goto fail;
8817
8818         btrfs_path_cachep = kmem_cache_create("btrfs_path",
8819                         sizeof(struct btrfs_path), 0,
8820                         SLAB_MEM_SPREAD, NULL);
8821         if (!btrfs_path_cachep)
8822                 goto fail;
8823
8824         btrfs_free_space_cachep = kmem_cache_create("btrfs_free_space",
8825                         sizeof(struct btrfs_free_space), 0,
8826                         SLAB_MEM_SPREAD, NULL);
8827         if (!btrfs_free_space_cachep)
8828                 goto fail;
8829
8830         btrfs_free_space_bitmap_cachep = kmem_cache_create("btrfs_free_space_bitmap",
8831                                                         PAGE_SIZE, PAGE_SIZE,
8832                                                         SLAB_RED_ZONE, NULL);
8833         if (!btrfs_free_space_bitmap_cachep)
8834                 goto fail;
8835
8836         return 0;
8837 fail:
8838         btrfs_destroy_cachep();
8839         return -ENOMEM;
8840 }
8841
8842 static int btrfs_getattr(const struct path *path, struct kstat *stat,
8843                          u32 request_mask, unsigned int flags)
8844 {
8845         u64 delalloc_bytes;
8846         struct inode *inode = d_inode(path->dentry);
8847         u32 blocksize = inode->i_sb->s_blocksize;
8848         u32 bi_flags = BTRFS_I(inode)->flags;
8849
8850         stat->result_mask |= STATX_BTIME;
8851         stat->btime.tv_sec = BTRFS_I(inode)->i_otime.tv_sec;
8852         stat->btime.tv_nsec = BTRFS_I(inode)->i_otime.tv_nsec;
8853         if (bi_flags & BTRFS_INODE_APPEND)
8854                 stat->attributes |= STATX_ATTR_APPEND;
8855         if (bi_flags & BTRFS_INODE_COMPRESS)
8856                 stat->attributes |= STATX_ATTR_COMPRESSED;
8857         if (bi_flags & BTRFS_INODE_IMMUTABLE)
8858                 stat->attributes |= STATX_ATTR_IMMUTABLE;
8859         if (bi_flags & BTRFS_INODE_NODUMP)
8860                 stat->attributes |= STATX_ATTR_NODUMP;
8861
8862         stat->attributes_mask |= (STATX_ATTR_APPEND |
8863                                   STATX_ATTR_COMPRESSED |
8864                                   STATX_ATTR_IMMUTABLE |
8865                                   STATX_ATTR_NODUMP);
8866
8867         generic_fillattr(inode, stat);
8868         stat->dev = BTRFS_I(inode)->root->anon_dev;
8869
8870         spin_lock(&BTRFS_I(inode)->lock);
8871         delalloc_bytes = BTRFS_I(inode)->new_delalloc_bytes;
8872         spin_unlock(&BTRFS_I(inode)->lock);
8873         stat->blocks = (ALIGN(inode_get_bytes(inode), blocksize) +
8874                         ALIGN(delalloc_bytes, blocksize)) >> 9;
8875         return 0;
8876 }
8877
8878 static int btrfs_rename_exchange(struct inode *old_dir,
8879                               struct dentry *old_dentry,
8880                               struct inode *new_dir,
8881                               struct dentry *new_dentry)
8882 {
8883         struct btrfs_fs_info *fs_info = btrfs_sb(old_dir->i_sb);
8884         struct btrfs_trans_handle *trans;
8885         struct btrfs_root *root = BTRFS_I(old_dir)->root;
8886         struct btrfs_root *dest = BTRFS_I(new_dir)->root;
8887         struct inode *new_inode = new_dentry->d_inode;
8888         struct inode *old_inode = old_dentry->d_inode;
8889         struct timespec64 ctime = current_time(old_inode);
8890         struct dentry *parent;
8891         u64 old_ino = btrfs_ino(BTRFS_I(old_inode));
8892         u64 new_ino = btrfs_ino(BTRFS_I(new_inode));
8893         u64 old_idx = 0;
8894         u64 new_idx = 0;
8895         int ret;
8896         bool root_log_pinned = false;
8897         bool dest_log_pinned = false;
8898         struct btrfs_log_ctx ctx_root;
8899         struct btrfs_log_ctx ctx_dest;
8900         bool sync_log_root = false;
8901         bool sync_log_dest = false;
8902         bool commit_transaction = false;
8903
8904         /* we only allow rename subvolume link between subvolumes */
8905         if (old_ino != BTRFS_FIRST_FREE_OBJECTID && root != dest)
8906                 return -EXDEV;
8907
8908         btrfs_init_log_ctx(&ctx_root, old_inode);
8909         btrfs_init_log_ctx(&ctx_dest, new_inode);
8910
8911         /* close the race window with snapshot create/destroy ioctl */
8912         if (old_ino == BTRFS_FIRST_FREE_OBJECTID ||
8913             new_ino == BTRFS_FIRST_FREE_OBJECTID)
8914                 down_read(&fs_info->subvol_sem);
8915
8916         /*
8917          * We want to reserve the absolute worst case amount of items.  So if
8918          * both inodes are subvols and we need to unlink them then that would
8919          * require 4 item modifications, but if they are both normal inodes it
8920          * would require 5 item modifications, so we'll assume their normal
8921          * inodes.  So 5 * 2 is 10, plus 2 for the new links, so 12 total items
8922          * should cover the worst case number of items we'll modify.
8923          */
8924         trans = btrfs_start_transaction(root, 12);
8925         if (IS_ERR(trans)) {
8926                 ret = PTR_ERR(trans);
8927                 goto out_notrans;
8928         }
8929
8930         if (dest != root)
8931                 btrfs_record_root_in_trans(trans, dest);
8932
8933         /*
8934          * We need to find a free sequence number both in the source and
8935          * in the destination directory for the exchange.
8936          */
8937         ret = btrfs_set_inode_index(BTRFS_I(new_dir), &old_idx);
8938         if (ret)
8939                 goto out_fail;
8940         ret = btrfs_set_inode_index(BTRFS_I(old_dir), &new_idx);
8941         if (ret)
8942                 goto out_fail;
8943
8944         BTRFS_I(old_inode)->dir_index = 0ULL;
8945         BTRFS_I(new_inode)->dir_index = 0ULL;
8946
8947         /* Reference for the source. */
8948         if (old_ino == BTRFS_FIRST_FREE_OBJECTID) {
8949                 /* force full log commit if subvolume involved. */
8950                 btrfs_set_log_full_commit(trans);
8951         } else {
8952                 btrfs_pin_log_trans(root);
8953                 root_log_pinned = true;
8954                 ret = btrfs_insert_inode_ref(trans, dest,
8955                                              new_dentry->d_name.name,
8956                                              new_dentry->d_name.len,
8957                                              old_ino,
8958                                              btrfs_ino(BTRFS_I(new_dir)),
8959                                              old_idx);
8960                 if (ret)
8961                         goto out_fail;
8962         }
8963
8964         /* And now for the dest. */
8965         if (new_ino == BTRFS_FIRST_FREE_OBJECTID) {
8966                 /* force full log commit if subvolume involved. */
8967                 btrfs_set_log_full_commit(trans);
8968         } else {
8969                 btrfs_pin_log_trans(dest);
8970                 dest_log_pinned = true;
8971                 ret = btrfs_insert_inode_ref(trans, root,
8972                                              old_dentry->d_name.name,
8973                                              old_dentry->d_name.len,
8974                                              new_ino,
8975                                              btrfs_ino(BTRFS_I(old_dir)),
8976                                              new_idx);
8977                 if (ret)
8978                         goto out_fail;
8979         }
8980
8981         /* Update inode version and ctime/mtime. */
8982         inode_inc_iversion(old_dir);
8983         inode_inc_iversion(new_dir);
8984         inode_inc_iversion(old_inode);
8985         inode_inc_iversion(new_inode);
8986         old_dir->i_ctime = old_dir->i_mtime = ctime;
8987         new_dir->i_ctime = new_dir->i_mtime = ctime;
8988         old_inode->i_ctime = ctime;
8989         new_inode->i_ctime = ctime;
8990
8991         if (old_dentry->d_parent != new_dentry->d_parent) {
8992                 btrfs_record_unlink_dir(trans, BTRFS_I(old_dir),
8993                                 BTRFS_I(old_inode), 1);
8994                 btrfs_record_unlink_dir(trans, BTRFS_I(new_dir),
8995                                 BTRFS_I(new_inode), 1);
8996         }
8997
8998         /* src is a subvolume */
8999         if (old_ino == BTRFS_FIRST_FREE_OBJECTID) {
9000                 ret = btrfs_unlink_subvol(trans, old_dir, old_dentry);
9001         } else { /* src is an inode */
9002                 ret = __btrfs_unlink_inode(trans, root, BTRFS_I(old_dir),
9003                                            BTRFS_I(old_dentry->d_inode),
9004                                            old_dentry->d_name.name,
9005                                            old_dentry->d_name.len);
9006                 if (!ret)
9007                         ret = btrfs_update_inode(trans, root, old_inode);
9008         }
9009         if (ret) {
9010                 btrfs_abort_transaction(trans, ret);
9011                 goto out_fail;
9012         }
9013
9014         /* dest is a subvolume */
9015         if (new_ino == BTRFS_FIRST_FREE_OBJECTID) {
9016                 ret = btrfs_unlink_subvol(trans, new_dir, new_dentry);
9017         } else { /* dest is an inode */
9018                 ret = __btrfs_unlink_inode(trans, dest, BTRFS_I(new_dir),
9019                                            BTRFS_I(new_dentry->d_inode),
9020                                            new_dentry->d_name.name,
9021                                            new_dentry->d_name.len);
9022                 if (!ret)
9023                         ret = btrfs_update_inode(trans, dest, new_inode);
9024         }
9025         if (ret) {
9026                 btrfs_abort_transaction(trans, ret);
9027                 goto out_fail;
9028         }
9029
9030         ret = btrfs_add_link(trans, BTRFS_I(new_dir), BTRFS_I(old_inode),
9031                              new_dentry->d_name.name,
9032                              new_dentry->d_name.len, 0, old_idx);
9033         if (ret) {
9034                 btrfs_abort_transaction(trans, ret);
9035                 goto out_fail;
9036         }
9037
9038         ret = btrfs_add_link(trans, BTRFS_I(old_dir), BTRFS_I(new_inode),
9039                              old_dentry->d_name.name,
9040                              old_dentry->d_name.len, 0, new_idx);
9041         if (ret) {
9042                 btrfs_abort_transaction(trans, ret);
9043                 goto out_fail;
9044         }
9045
9046         if (old_inode->i_nlink == 1)
9047                 BTRFS_I(old_inode)->dir_index = old_idx;
9048         if (new_inode->i_nlink == 1)
9049                 BTRFS_I(new_inode)->dir_index = new_idx;
9050
9051         if (root_log_pinned) {
9052                 parent = new_dentry->d_parent;
9053                 ret = btrfs_log_new_name(trans, BTRFS_I(old_inode),
9054                                          BTRFS_I(old_dir), parent,
9055                                          false, &ctx_root);
9056                 if (ret == BTRFS_NEED_LOG_SYNC)
9057                         sync_log_root = true;
9058                 else if (ret == BTRFS_NEED_TRANS_COMMIT)
9059                         commit_transaction = true;
9060                 ret = 0;
9061                 btrfs_end_log_trans(root);
9062                 root_log_pinned = false;
9063         }
9064         if (dest_log_pinned) {
9065                 if (!commit_transaction) {
9066                         parent = old_dentry->d_parent;
9067                         ret = btrfs_log_new_name(trans, BTRFS_I(new_inode),
9068                                                  BTRFS_I(new_dir), parent,
9069                                                  false, &ctx_dest);
9070                         if (ret == BTRFS_NEED_LOG_SYNC)
9071                                 sync_log_dest = true;
9072                         else if (ret == BTRFS_NEED_TRANS_COMMIT)
9073                                 commit_transaction = true;
9074                         ret = 0;
9075                 }
9076                 btrfs_end_log_trans(dest);
9077                 dest_log_pinned = false;
9078         }
9079 out_fail:
9080         /*
9081          * If we have pinned a log and an error happened, we unpin tasks
9082          * trying to sync the log and force them to fallback to a transaction
9083          * commit if the log currently contains any of the inodes involved in
9084          * this rename operation (to ensure we do not persist a log with an
9085          * inconsistent state for any of these inodes or leading to any
9086          * inconsistencies when replayed). If the transaction was aborted, the
9087          * abortion reason is propagated to userspace when attempting to commit
9088          * the transaction. If the log does not contain any of these inodes, we
9089          * allow the tasks to sync it.
9090          */
9091         if (ret && (root_log_pinned || dest_log_pinned)) {
9092                 if (btrfs_inode_in_log(BTRFS_I(old_dir), fs_info->generation) ||
9093                     btrfs_inode_in_log(BTRFS_I(new_dir), fs_info->generation) ||
9094                     btrfs_inode_in_log(BTRFS_I(old_inode), fs_info->generation) ||
9095                     (new_inode &&
9096                      btrfs_inode_in_log(BTRFS_I(new_inode), fs_info->generation)))
9097                         btrfs_set_log_full_commit(trans);
9098
9099                 if (root_log_pinned) {
9100                         btrfs_end_log_trans(root);
9101                         root_log_pinned = false;
9102                 }
9103                 if (dest_log_pinned) {
9104                         btrfs_end_log_trans(dest);
9105                         dest_log_pinned = false;
9106                 }
9107         }
9108         if (!ret && sync_log_root && !commit_transaction) {
9109                 ret = btrfs_sync_log(trans, BTRFS_I(old_inode)->root,
9110                                      &ctx_root);
9111                 if (ret)
9112                         commit_transaction = true;
9113         }
9114         if (!ret && sync_log_dest && !commit_transaction) {
9115                 ret = btrfs_sync_log(trans, BTRFS_I(new_inode)->root,
9116                                      &ctx_dest);
9117                 if (ret)
9118                         commit_transaction = true;
9119         }
9120         if (commit_transaction) {
9121                 /*
9122                  * We may have set commit_transaction when logging the new name
9123                  * in the destination root, in which case we left the source
9124                  * root context in the list of log contextes. So make sure we
9125                  * remove it to avoid invalid memory accesses, since the context
9126                  * was allocated in our stack frame.
9127                  */
9128                 if (sync_log_root) {
9129                         mutex_lock(&root->log_mutex);
9130                         list_del_init(&ctx_root.list);
9131                         mutex_unlock(&root->log_mutex);
9132                 }
9133                 ret = btrfs_commit_transaction(trans);
9134         } else {
9135                 int ret2;
9136
9137                 ret2 = btrfs_end_transaction(trans);
9138                 ret = ret ? ret : ret2;
9139         }
9140 out_notrans:
9141         if (new_ino == BTRFS_FIRST_FREE_OBJECTID ||
9142             old_ino == BTRFS_FIRST_FREE_OBJECTID)
9143                 up_read(&fs_info->subvol_sem);
9144
9145         ASSERT(list_empty(&ctx_root.list));
9146         ASSERT(list_empty(&ctx_dest.list));
9147
9148         return ret;
9149 }
9150
9151 static int btrfs_whiteout_for_rename(struct btrfs_trans_handle *trans,
9152                                      struct btrfs_root *root,
9153                                      struct inode *dir,
9154                                      struct dentry *dentry)
9155 {
9156         int ret;
9157         struct inode *inode;
9158         u64 objectid;
9159         u64 index;
9160
9161         ret = btrfs_find_free_ino(root, &objectid);
9162         if (ret)
9163                 return ret;
9164
9165         inode = btrfs_new_inode(trans, root, dir,
9166                                 dentry->d_name.name,
9167                                 dentry->d_name.len,
9168                                 btrfs_ino(BTRFS_I(dir)),
9169                                 objectid,
9170                                 S_IFCHR | WHITEOUT_MODE,
9171                                 &index);
9172
9173         if (IS_ERR(inode)) {
9174                 ret = PTR_ERR(inode);
9175                 return ret;
9176         }
9177
9178         inode->i_op = &btrfs_special_inode_operations;
9179         init_special_inode(inode, inode->i_mode,
9180                 WHITEOUT_DEV);
9181
9182         ret = btrfs_init_inode_security(trans, inode, dir,
9183                                 &dentry->d_name);
9184         if (ret)
9185                 goto out;
9186
9187         ret = btrfs_add_nondir(trans, BTRFS_I(dir), dentry,
9188                                 BTRFS_I(inode), 0, index);
9189         if (ret)
9190                 goto out;
9191
9192         ret = btrfs_update_inode(trans, root, inode);
9193 out:
9194         unlock_new_inode(inode);
9195         if (ret)
9196                 inode_dec_link_count(inode);
9197         iput(inode);
9198
9199         return ret;
9200 }
9201
9202 static int btrfs_rename(struct inode *old_dir, struct dentry *old_dentry,
9203                            struct inode *new_dir, struct dentry *new_dentry,
9204                            unsigned int flags)
9205 {
9206         struct btrfs_fs_info *fs_info = btrfs_sb(old_dir->i_sb);
9207         struct btrfs_trans_handle *trans;
9208         unsigned int trans_num_items;
9209         struct btrfs_root *root = BTRFS_I(old_dir)->root;
9210         struct btrfs_root *dest = BTRFS_I(new_dir)->root;
9211         struct inode *new_inode = d_inode(new_dentry);
9212         struct inode *old_inode = d_inode(old_dentry);
9213         u64 index = 0;
9214         int ret;
9215         u64 old_ino = btrfs_ino(BTRFS_I(old_inode));
9216         bool log_pinned = false;
9217         struct btrfs_log_ctx ctx;
9218         bool sync_log = false;
9219         bool commit_transaction = false;
9220
9221         if (btrfs_ino(BTRFS_I(new_dir)) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
9222                 return -EPERM;
9223
9224         /* we only allow rename subvolume link between subvolumes */
9225         if (old_ino != BTRFS_FIRST_FREE_OBJECTID && root != dest)
9226                 return -EXDEV;
9227
9228         if (old_ino == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID ||
9229             (new_inode && btrfs_ino(BTRFS_I(new_inode)) == BTRFS_FIRST_FREE_OBJECTID))
9230                 return -ENOTEMPTY;
9231
9232         if (S_ISDIR(old_inode->i_mode) && new_inode &&
9233             new_inode->i_size > BTRFS_EMPTY_DIR_SIZE)
9234                 return -ENOTEMPTY;
9235
9236
9237         /* check for collisions, even if the  name isn't there */
9238         ret = btrfs_check_dir_item_collision(dest, new_dir->i_ino,
9239                              new_dentry->d_name.name,
9240                              new_dentry->d_name.len);
9241
9242         if (ret) {
9243                 if (ret == -EEXIST) {
9244                         /* we shouldn't get
9245                          * eexist without a new_inode */
9246                         if (WARN_ON(!new_inode)) {
9247                                 return ret;
9248                         }
9249                 } else {
9250                         /* maybe -EOVERFLOW */
9251                         return ret;
9252                 }
9253         }
9254         ret = 0;
9255
9256         /*
9257          * we're using rename to replace one file with another.  Start IO on it
9258          * now so  we don't add too much work to the end of the transaction
9259          */
9260         if (new_inode && S_ISREG(old_inode->i_mode) && new_inode->i_size)
9261                 filemap_flush(old_inode->i_mapping);
9262
9263         /* close the racy window with snapshot create/destroy ioctl */
9264         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
9265                 down_read(&fs_info->subvol_sem);
9266         /*
9267          * We want to reserve the absolute worst case amount of items.  So if
9268          * both inodes are subvols and we need to unlink them then that would
9269          * require 4 item modifications, but if they are both normal inodes it
9270          * would require 5 item modifications, so we'll assume they are normal
9271          * inodes.  So 5 * 2 is 10, plus 1 for the new link, so 11 total items
9272          * should cover the worst case number of items we'll modify.
9273          * If our rename has the whiteout flag, we need more 5 units for the
9274          * new inode (1 inode item, 1 inode ref, 2 dir items and 1 xattr item
9275          * when selinux is enabled).
9276          */
9277         trans_num_items = 11;
9278         if (flags & RENAME_WHITEOUT)
9279                 trans_num_items += 5;
9280         trans = btrfs_start_transaction(root, trans_num_items);
9281         if (IS_ERR(trans)) {
9282                 ret = PTR_ERR(trans);
9283                 goto out_notrans;
9284         }
9285
9286         if (dest != root)
9287                 btrfs_record_root_in_trans(trans, dest);
9288
9289         ret = btrfs_set_inode_index(BTRFS_I(new_dir), &index);
9290         if (ret)
9291                 goto out_fail;
9292
9293         BTRFS_I(old_inode)->dir_index = 0ULL;
9294         if (unlikely(old_ino == BTRFS_FIRST_FREE_OBJECTID)) {
9295                 /* force full log commit if subvolume involved. */
9296                 btrfs_set_log_full_commit(trans);
9297         } else {
9298                 btrfs_pin_log_trans(root);
9299                 log_pinned = true;
9300                 ret = btrfs_insert_inode_ref(trans, dest,
9301                                              new_dentry->d_name.name,
9302                                              new_dentry->d_name.len,
9303                                              old_ino,
9304                                              btrfs_ino(BTRFS_I(new_dir)), index);
9305                 if (ret)
9306                         goto out_fail;
9307         }
9308
9309         inode_inc_iversion(old_dir);
9310         inode_inc_iversion(new_dir);
9311         inode_inc_iversion(old_inode);
9312         old_dir->i_ctime = old_dir->i_mtime =
9313         new_dir->i_ctime = new_dir->i_mtime =
9314         old_inode->i_ctime = current_time(old_dir);
9315
9316         if (old_dentry->d_parent != new_dentry->d_parent)
9317                 btrfs_record_unlink_dir(trans, BTRFS_I(old_dir),
9318                                 BTRFS_I(old_inode), 1);
9319
9320         if (unlikely(old_ino == BTRFS_FIRST_FREE_OBJECTID)) {
9321                 ret = btrfs_unlink_subvol(trans, old_dir, old_dentry);
9322         } else {
9323                 ret = __btrfs_unlink_inode(trans, root, BTRFS_I(old_dir),
9324                                         BTRFS_I(d_inode(old_dentry)),
9325                                         old_dentry->d_name.name,
9326                                         old_dentry->d_name.len);
9327                 if (!ret)
9328                         ret = btrfs_update_inode(trans, root, old_inode);
9329         }
9330         if (ret) {
9331                 btrfs_abort_transaction(trans, ret);
9332                 goto out_fail;
9333         }
9334
9335         if (new_inode) {
9336                 inode_inc_iversion(new_inode);
9337                 new_inode->i_ctime = current_time(new_inode);
9338                 if (unlikely(btrfs_ino(BTRFS_I(new_inode)) ==
9339                              BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
9340                         ret = btrfs_unlink_subvol(trans, new_dir, new_dentry);
9341                         BUG_ON(new_inode->i_nlink == 0);
9342                 } else {
9343                         ret = btrfs_unlink_inode(trans, dest, BTRFS_I(new_dir),
9344                                                  BTRFS_I(d_inode(new_dentry)),
9345                                                  new_dentry->d_name.name,
9346                                                  new_dentry->d_name.len);
9347                 }
9348                 if (!ret && new_inode->i_nlink == 0)
9349                         ret = btrfs_orphan_add(trans,
9350                                         BTRFS_I(d_inode(new_dentry)));
9351                 if (ret) {
9352                         btrfs_abort_transaction(trans, ret);
9353                         goto out_fail;
9354                 }
9355         }
9356
9357         ret = btrfs_add_link(trans, BTRFS_I(new_dir), BTRFS_I(old_inode),
9358                              new_dentry->d_name.name,
9359                              new_dentry->d_name.len, 0, index);
9360         if (ret) {
9361                 btrfs_abort_transaction(trans, ret);
9362                 goto out_fail;
9363         }
9364
9365         if (old_inode->i_nlink == 1)
9366                 BTRFS_I(old_inode)->dir_index = index;
9367
9368         if (log_pinned) {
9369                 struct dentry *parent = new_dentry->d_parent;
9370
9371                 btrfs_init_log_ctx(&ctx, old_inode);
9372                 ret = btrfs_log_new_name(trans, BTRFS_I(old_inode),
9373                                          BTRFS_I(old_dir), parent,
9374                                          false, &ctx);
9375                 if (ret == BTRFS_NEED_LOG_SYNC)
9376                         sync_log = true;
9377                 else if (ret == BTRFS_NEED_TRANS_COMMIT)
9378                         commit_transaction = true;
9379                 ret = 0;
9380                 btrfs_end_log_trans(root);
9381                 log_pinned = false;
9382         }
9383
9384         if (flags & RENAME_WHITEOUT) {
9385                 ret = btrfs_whiteout_for_rename(trans, root, old_dir,
9386                                                 old_dentry);
9387
9388                 if (ret) {
9389                         btrfs_abort_transaction(trans, ret);
9390                         goto out_fail;
9391                 }
9392         }
9393 out_fail:
9394         /*
9395          * If we have pinned the log and an error happened, we unpin tasks
9396          * trying to sync the log and force them to fallback to a transaction
9397          * commit if the log currently contains any of the inodes involved in
9398          * this rename operation (to ensure we do not persist a log with an
9399          * inconsistent state for any of these inodes or leading to any
9400          * inconsistencies when replayed). If the transaction was aborted, the
9401          * abortion reason is propagated to userspace when attempting to commit
9402          * the transaction. If the log does not contain any of these inodes, we
9403          * allow the tasks to sync it.
9404          */
9405         if (ret && log_pinned) {
9406                 if (btrfs_inode_in_log(BTRFS_I(old_dir), fs_info->generation) ||
9407                     btrfs_inode_in_log(BTRFS_I(new_dir), fs_info->generation) ||
9408                     btrfs_inode_in_log(BTRFS_I(old_inode), fs_info->generation) ||
9409                     (new_inode &&
9410                      btrfs_inode_in_log(BTRFS_I(new_inode), fs_info->generation)))
9411                         btrfs_set_log_full_commit(trans);
9412
9413                 btrfs_end_log_trans(root);
9414                 log_pinned = false;
9415         }
9416         if (!ret && sync_log) {
9417                 ret = btrfs_sync_log(trans, BTRFS_I(old_inode)->root, &ctx);
9418                 if (ret)
9419                         commit_transaction = true;
9420         }
9421         if (commit_transaction) {
9422                 ret = btrfs_commit_transaction(trans);
9423         } else {
9424                 int ret2;
9425
9426                 ret2 = btrfs_end_transaction(trans);
9427                 ret = ret ? ret : ret2;
9428         }
9429 out_notrans:
9430         if (old_ino == BTRFS_FIRST_FREE_OBJECTID)
9431                 up_read(&fs_info->subvol_sem);
9432
9433         return ret;
9434 }
9435
9436 static int btrfs_rename2(struct inode *old_dir, struct dentry *old_dentry,
9437                          struct inode *new_dir, struct dentry *new_dentry,
9438                          unsigned int flags)
9439 {
9440         if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT))
9441                 return -EINVAL;
9442
9443         if (flags & RENAME_EXCHANGE)
9444                 return btrfs_rename_exchange(old_dir, old_dentry, new_dir,
9445                                           new_dentry);
9446
9447         return btrfs_rename(old_dir, old_dentry, new_dir, new_dentry, flags);
9448 }
9449
9450 struct btrfs_delalloc_work {
9451         struct inode *inode;
9452         struct completion completion;
9453         struct list_head list;
9454         struct btrfs_work work;
9455 };
9456
9457 static void btrfs_run_delalloc_work(struct btrfs_work *work)
9458 {
9459         struct btrfs_delalloc_work *delalloc_work;
9460         struct inode *inode;
9461
9462         delalloc_work = container_of(work, struct btrfs_delalloc_work,
9463                                      work);
9464         inode = delalloc_work->inode;
9465         filemap_flush(inode->i_mapping);
9466         if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
9467                                 &BTRFS_I(inode)->runtime_flags))
9468                 filemap_flush(inode->i_mapping);
9469
9470         iput(inode);
9471         complete(&delalloc_work->completion);
9472 }
9473
9474 static struct btrfs_delalloc_work *btrfs_alloc_delalloc_work(struct inode *inode)
9475 {
9476         struct btrfs_delalloc_work *work;
9477
9478         work = kmalloc(sizeof(*work), GFP_NOFS);
9479         if (!work)
9480                 return NULL;
9481
9482         init_completion(&work->completion);
9483         INIT_LIST_HEAD(&work->list);
9484         work->inode = inode;
9485         btrfs_init_work(&work->work, btrfs_run_delalloc_work, NULL, NULL);
9486
9487         return work;
9488 }
9489
9490 /*
9491  * some fairly slow code that needs optimization. This walks the list
9492  * of all the inodes with pending delalloc and forces them to disk.
9493  */
9494 static int start_delalloc_inodes(struct btrfs_root *root, int nr, bool snapshot)
9495 {
9496         struct btrfs_inode *binode;
9497         struct inode *inode;
9498         struct btrfs_delalloc_work *work, *next;
9499         struct list_head works;
9500         struct list_head splice;
9501         int ret = 0;
9502
9503         INIT_LIST_HEAD(&works);
9504         INIT_LIST_HEAD(&splice);
9505
9506         mutex_lock(&root->delalloc_mutex);
9507         spin_lock(&root->delalloc_lock);
9508         list_splice_init(&root->delalloc_inodes, &splice);
9509         while (!list_empty(&splice)) {
9510                 binode = list_entry(splice.next, struct btrfs_inode,
9511                                     delalloc_inodes);
9512
9513                 list_move_tail(&binode->delalloc_inodes,
9514                                &root->delalloc_inodes);
9515                 inode = igrab(&binode->vfs_inode);
9516                 if (!inode) {
9517                         cond_resched_lock(&root->delalloc_lock);
9518                         continue;
9519                 }
9520                 spin_unlock(&root->delalloc_lock);
9521
9522                 if (snapshot)
9523                         set_bit(BTRFS_INODE_SNAPSHOT_FLUSH,
9524                                 &binode->runtime_flags);
9525                 work = btrfs_alloc_delalloc_work(inode);
9526                 if (!work) {
9527                         iput(inode);
9528                         ret = -ENOMEM;
9529                         goto out;
9530                 }
9531                 list_add_tail(&work->list, &works);
9532                 btrfs_queue_work(root->fs_info->flush_workers,
9533                                  &work->work);
9534                 ret++;
9535                 if (nr != -1 && ret >= nr)
9536                         goto out;
9537                 cond_resched();
9538                 spin_lock(&root->delalloc_lock);
9539         }
9540         spin_unlock(&root->delalloc_lock);
9541
9542 out:
9543         list_for_each_entry_safe(work, next, &works, list) {
9544                 list_del_init(&work->list);
9545                 wait_for_completion(&work->completion);
9546                 kfree(work);
9547         }
9548
9549         if (!list_empty(&splice)) {
9550                 spin_lock(&root->delalloc_lock);
9551                 list_splice_tail(&splice, &root->delalloc_inodes);
9552                 spin_unlock(&root->delalloc_lock);
9553         }
9554         mutex_unlock(&root->delalloc_mutex);
9555         return ret;
9556 }
9557
9558 int btrfs_start_delalloc_snapshot(struct btrfs_root *root)
9559 {
9560         struct btrfs_fs_info *fs_info = root->fs_info;
9561         int ret;
9562
9563         if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
9564                 return -EROFS;
9565
9566         ret = start_delalloc_inodes(root, -1, true);
9567         if (ret > 0)
9568                 ret = 0;
9569         return ret;
9570 }
9571
9572 int btrfs_start_delalloc_roots(struct btrfs_fs_info *fs_info, int nr)
9573 {
9574         struct btrfs_root *root;
9575         struct list_head splice;
9576         int ret;
9577
9578         if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
9579                 return -EROFS;
9580
9581         INIT_LIST_HEAD(&splice);
9582
9583         mutex_lock(&fs_info->delalloc_root_mutex);
9584         spin_lock(&fs_info->delalloc_root_lock);
9585         list_splice_init(&fs_info->delalloc_roots, &splice);
9586         while (!list_empty(&splice) && nr) {
9587                 root = list_first_entry(&splice, struct btrfs_root,
9588                                         delalloc_root);
9589                 root = btrfs_grab_fs_root(root);
9590                 BUG_ON(!root);
9591                 list_move_tail(&root->delalloc_root,
9592                                &fs_info->delalloc_roots);
9593                 spin_unlock(&fs_info->delalloc_root_lock);
9594
9595                 ret = start_delalloc_inodes(root, nr, false);
9596                 btrfs_put_fs_root(root);
9597                 if (ret < 0)
9598                         goto out;
9599
9600                 if (nr != -1) {
9601                         nr -= ret;
9602                         WARN_ON(nr < 0);
9603                 }
9604                 spin_lock(&fs_info->delalloc_root_lock);
9605         }
9606         spin_unlock(&fs_info->delalloc_root_lock);
9607
9608         ret = 0;
9609 out:
9610         if (!list_empty(&splice)) {
9611                 spin_lock(&fs_info->delalloc_root_lock);
9612                 list_splice_tail(&splice, &fs_info->delalloc_roots);
9613                 spin_unlock(&fs_info->delalloc_root_lock);
9614         }
9615         mutex_unlock(&fs_info->delalloc_root_mutex);
9616         return ret;
9617 }
9618
9619 static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
9620                          const char *symname)
9621 {
9622         struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
9623         struct btrfs_trans_handle *trans;
9624         struct btrfs_root *root = BTRFS_I(dir)->root;
9625         struct btrfs_path *path;
9626         struct btrfs_key key;
9627         struct inode *inode = NULL;
9628         int err;
9629         u64 objectid;
9630         u64 index = 0;
9631         int name_len;
9632         int datasize;
9633         unsigned long ptr;
9634         struct btrfs_file_extent_item *ei;
9635         struct extent_buffer *leaf;
9636
9637         name_len = strlen(symname);
9638         if (name_len > BTRFS_MAX_INLINE_DATA_SIZE(fs_info))
9639                 return -ENAMETOOLONG;
9640
9641         /*
9642          * 2 items for inode item and ref
9643          * 2 items for dir items
9644          * 1 item for updating parent inode item
9645          * 1 item for the inline extent item
9646          * 1 item for xattr if selinux is on
9647          */
9648         trans = btrfs_start_transaction(root, 7);
9649         if (IS_ERR(trans))
9650                 return PTR_ERR(trans);
9651
9652         err = btrfs_find_free_ino(root, &objectid);
9653         if (err)
9654                 goto out_unlock;
9655
9656         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
9657                                 dentry->d_name.len, btrfs_ino(BTRFS_I(dir)),
9658                                 objectid, S_IFLNK|S_IRWXUGO, &index);
9659         if (IS_ERR(inode)) {
9660                 err = PTR_ERR(inode);
9661                 inode = NULL;
9662                 goto out_unlock;
9663         }
9664
9665         /*
9666         * If the active LSM wants to access the inode during
9667         * d_instantiate it needs these. Smack checks to see
9668         * if the filesystem supports xattrs by looking at the
9669         * ops vector.
9670         */
9671         inode->i_fop = &btrfs_file_operations;
9672         inode->i_op = &btrfs_file_inode_operations;
9673         inode->i_mapping->a_ops = &btrfs_aops;
9674         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
9675
9676         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
9677         if (err)
9678                 goto out_unlock;
9679
9680         path = btrfs_alloc_path();
9681         if (!path) {
9682                 err = -ENOMEM;
9683                 goto out_unlock;
9684         }
9685         key.objectid = btrfs_ino(BTRFS_I(inode));
9686         key.offset = 0;
9687         key.type = BTRFS_EXTENT_DATA_KEY;
9688         datasize = btrfs_file_extent_calc_inline_size(name_len);
9689         err = btrfs_insert_empty_item(trans, root, path, &key,
9690                                       datasize);
9691         if (err) {
9692                 btrfs_free_path(path);
9693                 goto out_unlock;
9694         }
9695         leaf = path->nodes[0];
9696         ei = btrfs_item_ptr(leaf, path->slots[0],
9697                             struct btrfs_file_extent_item);
9698         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
9699         btrfs_set_file_extent_type(leaf, ei,
9700                                    BTRFS_FILE_EXTENT_INLINE);
9701         btrfs_set_file_extent_encryption(leaf, ei, 0);
9702         btrfs_set_file_extent_compression(leaf, ei, 0);
9703         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
9704         btrfs_set_file_extent_ram_bytes(leaf, ei, name_len);
9705
9706         ptr = btrfs_file_extent_inline_start(ei);
9707         write_extent_buffer(leaf, symname, ptr, name_len);
9708         btrfs_mark_buffer_dirty(leaf);
9709         btrfs_free_path(path);
9710
9711         inode->i_op = &btrfs_symlink_inode_operations;
9712         inode_nohighmem(inode);
9713         inode_set_bytes(inode, name_len);
9714         btrfs_i_size_write(BTRFS_I(inode), name_len);
9715         err = btrfs_update_inode(trans, root, inode);
9716         /*
9717          * Last step, add directory indexes for our symlink inode. This is the
9718          * last step to avoid extra cleanup of these indexes if an error happens
9719          * elsewhere above.
9720          */
9721         if (!err)
9722                 err = btrfs_add_nondir(trans, BTRFS_I(dir), dentry,
9723                                 BTRFS_I(inode), 0, index);
9724         if (err)
9725                 goto out_unlock;
9726
9727         d_instantiate_new(dentry, inode);
9728
9729 out_unlock:
9730         btrfs_end_transaction(trans);
9731         if (err && inode) {
9732                 inode_dec_link_count(inode);
9733                 discard_new_inode(inode);
9734         }
9735         btrfs_btree_balance_dirty(fs_info);
9736         return err;
9737 }
9738
9739 static int __btrfs_prealloc_file_range(struct inode *inode, int mode,
9740                                        u64 start, u64 num_bytes, u64 min_size,
9741                                        loff_t actual_len, u64 *alloc_hint,
9742                                        struct btrfs_trans_handle *trans)
9743 {
9744         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
9745         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
9746         struct extent_map *em;
9747         struct btrfs_root *root = BTRFS_I(inode)->root;
9748         struct btrfs_key ins;
9749         u64 cur_offset = start;
9750         u64 i_size;
9751         u64 cur_bytes;
9752         u64 last_alloc = (u64)-1;
9753         int ret = 0;
9754         bool own_trans = true;
9755         u64 end = start + num_bytes - 1;
9756
9757         if (trans)
9758                 own_trans = false;
9759         while (num_bytes > 0) {
9760                 if (own_trans) {
9761                         trans = btrfs_start_transaction(root, 3);
9762                         if (IS_ERR(trans)) {
9763                                 ret = PTR_ERR(trans);
9764                                 break;
9765                         }
9766                 }
9767
9768                 cur_bytes = min_t(u64, num_bytes, SZ_256M);
9769                 cur_bytes = max(cur_bytes, min_size);
9770                 /*
9771                  * If we are severely fragmented we could end up with really
9772                  * small allocations, so if the allocator is returning small
9773                  * chunks lets make its job easier by only searching for those
9774                  * sized chunks.
9775                  */
9776                 cur_bytes = min(cur_bytes, last_alloc);
9777                 ret = btrfs_reserve_extent(root, cur_bytes, cur_bytes,
9778                                 min_size, 0, *alloc_hint, &ins, 1, 0);
9779                 if (ret) {
9780                         if (own_trans)
9781                                 btrfs_end_transaction(trans);
9782                         break;
9783                 }
9784                 btrfs_dec_block_group_reservations(fs_info, ins.objectid);
9785
9786                 last_alloc = ins.offset;
9787                 ret = insert_reserved_file_extent(trans, inode,
9788                                                   cur_offset, ins.objectid,
9789                                                   ins.offset, ins.offset,
9790                                                   ins.offset, 0, 0, 0,
9791                                                   BTRFS_FILE_EXTENT_PREALLOC);
9792                 if (ret) {
9793                         btrfs_free_reserved_extent(fs_info, ins.objectid,
9794                                                    ins.offset, 0);
9795                         btrfs_abort_transaction(trans, ret);
9796                         if (own_trans)
9797                                 btrfs_end_transaction(trans);
9798                         break;
9799                 }
9800
9801                 btrfs_drop_extent_cache(BTRFS_I(inode), cur_offset,
9802                                         cur_offset + ins.offset -1, 0);
9803
9804                 em = alloc_extent_map();
9805                 if (!em) {
9806                         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
9807                                 &BTRFS_I(inode)->runtime_flags);
9808                         goto next;
9809                 }
9810
9811                 em->start = cur_offset;
9812                 em->orig_start = cur_offset;
9813                 em->len = ins.offset;
9814                 em->block_start = ins.objectid;
9815                 em->block_len = ins.offset;
9816                 em->orig_block_len = ins.offset;
9817                 em->ram_bytes = ins.offset;
9818                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
9819                 em->generation = trans->transid;
9820
9821                 while (1) {
9822                         write_lock(&em_tree->lock);
9823                         ret = add_extent_mapping(em_tree, em, 1);
9824                         write_unlock(&em_tree->lock);
9825                         if (ret != -EEXIST)
9826                                 break;
9827                         btrfs_drop_extent_cache(BTRFS_I(inode), cur_offset,
9828                                                 cur_offset + ins.offset - 1,
9829                                                 0);
9830                 }
9831                 free_extent_map(em);
9832 next:
9833                 num_bytes -= ins.offset;
9834                 cur_offset += ins.offset;
9835                 *alloc_hint = ins.objectid + ins.offset;
9836
9837                 inode_inc_iversion(inode);
9838                 inode->i_ctime = current_time(inode);
9839                 BTRFS_I(inode)->flags |= BTRFS_INODE_PREALLOC;
9840                 if (!(mode & FALLOC_FL_KEEP_SIZE) &&
9841                     (actual_len > inode->i_size) &&
9842                     (cur_offset > inode->i_size)) {
9843                         if (cur_offset > actual_len)
9844                                 i_size = actual_len;
9845                         else
9846                                 i_size = cur_offset;
9847                         i_size_write(inode, i_size);
9848                         btrfs_ordered_update_i_size(inode, i_size, NULL);
9849                 }
9850
9851                 ret = btrfs_update_inode(trans, root, inode);
9852
9853                 if (ret) {
9854                         btrfs_abort_transaction(trans, ret);
9855                         if (own_trans)
9856                                 btrfs_end_transaction(trans);
9857                         break;
9858                 }
9859
9860                 if (own_trans)
9861                         btrfs_end_transaction(trans);
9862         }
9863         if (cur_offset < end)
9864                 btrfs_free_reserved_data_space(inode, NULL, cur_offset,
9865                         end - cur_offset + 1);
9866         return ret;
9867 }
9868
9869 int btrfs_prealloc_file_range(struct inode *inode, int mode,
9870                               u64 start, u64 num_bytes, u64 min_size,
9871                               loff_t actual_len, u64 *alloc_hint)
9872 {
9873         return __btrfs_prealloc_file_range(inode, mode, start, num_bytes,
9874                                            min_size, actual_len, alloc_hint,
9875                                            NULL);
9876 }
9877
9878 int btrfs_prealloc_file_range_trans(struct inode *inode,
9879                                     struct btrfs_trans_handle *trans, int mode,
9880                                     u64 start, u64 num_bytes, u64 min_size,
9881                                     loff_t actual_len, u64 *alloc_hint)
9882 {
9883         return __btrfs_prealloc_file_range(inode, mode, start, num_bytes,
9884                                            min_size, actual_len, alloc_hint, trans);
9885 }
9886
9887 static int btrfs_set_page_dirty(struct page *page)
9888 {
9889         return __set_page_dirty_nobuffers(page);
9890 }
9891
9892 static int btrfs_permission(struct inode *inode, int mask)
9893 {
9894         struct btrfs_root *root = BTRFS_I(inode)->root;
9895         umode_t mode = inode->i_mode;
9896
9897         if (mask & MAY_WRITE &&
9898             (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode))) {
9899                 if (btrfs_root_readonly(root))
9900                         return -EROFS;
9901                 if (BTRFS_I(inode)->flags & BTRFS_INODE_READONLY)
9902                         return -EACCES;
9903         }
9904         return generic_permission(inode, mask);
9905 }
9906
9907 static int btrfs_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
9908 {
9909         struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
9910         struct btrfs_trans_handle *trans;
9911         struct btrfs_root *root = BTRFS_I(dir)->root;
9912         struct inode *inode = NULL;
9913         u64 objectid;
9914         u64 index;
9915         int ret = 0;
9916
9917         /*
9918          * 5 units required for adding orphan entry
9919          */
9920         trans = btrfs_start_transaction(root, 5);
9921         if (IS_ERR(trans))
9922                 return PTR_ERR(trans);
9923
9924         ret = btrfs_find_free_ino(root, &objectid);
9925         if (ret)
9926                 goto out;
9927
9928         inode = btrfs_new_inode(trans, root, dir, NULL, 0,
9929                         btrfs_ino(BTRFS_I(dir)), objectid, mode, &index);
9930         if (IS_ERR(inode)) {
9931                 ret = PTR_ERR(inode);
9932                 inode = NULL;
9933                 goto out;
9934         }
9935
9936         inode->i_fop = &btrfs_file_operations;
9937         inode->i_op = &btrfs_file_inode_operations;
9938
9939         inode->i_mapping->a_ops = &btrfs_aops;
9940         BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
9941
9942         ret = btrfs_init_inode_security(trans, inode, dir, NULL);
9943         if (ret)
9944                 goto out;
9945
9946         ret = btrfs_update_inode(trans, root, inode);
9947         if (ret)
9948                 goto out;
9949         ret = btrfs_orphan_add(trans, BTRFS_I(inode));
9950         if (ret)
9951                 goto out;
9952
9953         /*
9954          * We set number of links to 0 in btrfs_new_inode(), and here we set
9955          * it to 1 because d_tmpfile() will issue a warning if the count is 0,
9956          * through:
9957          *
9958          *    d_tmpfile() -> inode_dec_link_count() -> drop_nlink()
9959          */
9960         set_nlink(inode, 1);
9961         d_tmpfile(dentry, inode);
9962         unlock_new_inode(inode);
9963         mark_inode_dirty(inode);
9964 out:
9965         btrfs_end_transaction(trans);
9966         if (ret && inode)
9967                 discard_new_inode(inode);
9968         btrfs_btree_balance_dirty(fs_info);
9969         return ret;
9970 }
9971
9972 void btrfs_set_range_writeback(struct extent_io_tree *tree, u64 start, u64 end)
9973 {
9974         struct inode *inode = tree->private_data;
9975         unsigned long index = start >> PAGE_SHIFT;
9976         unsigned long end_index = end >> PAGE_SHIFT;
9977         struct page *page;
9978
9979         while (index <= end_index) {
9980                 page = find_get_page(inode->i_mapping, index);
9981                 ASSERT(page); /* Pages should be in the extent_io_tree */
9982                 set_page_writeback(page);
9983                 put_page(page);
9984                 index++;
9985         }
9986 }
9987
9988 #ifdef CONFIG_SWAP
9989 /*
9990  * Add an entry indicating a block group or device which is pinned by a
9991  * swapfile. Returns 0 on success, 1 if there is already an entry for it, or a
9992  * negative errno on failure.
9993  */
9994 static int btrfs_add_swapfile_pin(struct inode *inode, void *ptr,
9995                                   bool is_block_group)
9996 {
9997         struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
9998         struct btrfs_swapfile_pin *sp, *entry;
9999         struct rb_node **p;
10000         struct rb_node *parent = NULL;
10001
10002         sp = kmalloc(sizeof(*sp), GFP_NOFS);
10003         if (!sp)
10004                 return -ENOMEM;
10005         sp->ptr = ptr;
10006         sp->inode = inode;
10007         sp->is_block_group = is_block_group;
10008
10009         spin_lock(&fs_info->swapfile_pins_lock);
10010         p = &fs_info->swapfile_pins.rb_node;
10011         while (*p) {
10012                 parent = *p;
10013                 entry = rb_entry(parent, struct btrfs_swapfile_pin, node);
10014                 if (sp->ptr < entry->ptr ||
10015                     (sp->ptr == entry->ptr && sp->inode < entry->inode)) {
10016                         p = &(*p)->rb_left;
10017                 } else if (sp->ptr > entry->ptr ||
10018                            (sp->ptr == entry->ptr && sp->inode > entry->inode)) {
10019                         p = &(*p)->rb_right;
10020                 } else {
10021                         spin_unlock(&fs_info->swapfile_pins_lock);
10022                         kfree(sp);
10023                         return 1;
10024                 }
10025         }
10026         rb_link_node(&sp->node, parent, p);
10027         rb_insert_color(&sp->node, &fs_info->swapfile_pins);
10028         spin_unlock(&fs_info->swapfile_pins_lock);
10029         return 0;
10030 }
10031
10032 /* Free all of the entries pinned by this swapfile. */
10033 static void btrfs_free_swapfile_pins(struct inode *inode)
10034 {
10035         struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
10036         struct btrfs_swapfile_pin *sp;
10037         struct rb_node *node, *next;
10038
10039         spin_lock(&fs_info->swapfile_pins_lock);
10040         node = rb_first(&fs_info->swapfile_pins);
10041         while (node) {
10042                 next = rb_next(node);
10043                 sp = rb_entry(node, struct btrfs_swapfile_pin, node);
10044                 if (sp->inode == inode) {
10045                         rb_erase(&sp->node, &fs_info->swapfile_pins);
10046                         if (sp->is_block_group)
10047                                 btrfs_put_block_group(sp->ptr);
10048                         kfree(sp);
10049                 }
10050                 node = next;
10051         }
10052         spin_unlock(&fs_info->swapfile_pins_lock);
10053 }
10054
10055 struct btrfs_swap_info {
10056         u64 start;
10057         u64 block_start;
10058         u64 block_len;
10059         u64 lowest_ppage;
10060         u64 highest_ppage;
10061         unsigned long nr_pages;
10062         int nr_extents;
10063 };
10064
10065 static int btrfs_add_swap_extent(struct swap_info_struct *sis,
10066                                  struct btrfs_swap_info *bsi)
10067 {
10068         unsigned long nr_pages;
10069         u64 first_ppage, first_ppage_reported, next_ppage;
10070         int ret;
10071
10072         first_ppage = ALIGN(bsi->block_start, PAGE_SIZE) >> PAGE_SHIFT;
10073         next_ppage = ALIGN_DOWN(bsi->block_start + bsi->block_len,
10074                                 PAGE_SIZE) >> PAGE_SHIFT;
10075
10076         if (first_ppage >= next_ppage)
10077                 return 0;
10078         nr_pages = next_ppage - first_ppage;
10079
10080         first_ppage_reported = first_ppage;
10081         if (bsi->start == 0)
10082                 first_ppage_reported++;
10083         if (bsi->lowest_ppage > first_ppage_reported)
10084                 bsi->lowest_ppage = first_ppage_reported;
10085         if (bsi->highest_ppage < (next_ppage - 1))
10086                 bsi->highest_ppage = next_ppage - 1;
10087
10088         ret = add_swap_extent(sis, bsi->nr_pages, nr_pages, first_ppage);
10089         if (ret < 0)
10090                 return ret;
10091         bsi->nr_extents += ret;
10092         bsi->nr_pages += nr_pages;
10093         return 0;
10094 }
10095
10096 static void btrfs_swap_deactivate(struct file *file)
10097 {
10098         struct inode *inode = file_inode(file);
10099
10100         btrfs_free_swapfile_pins(inode);
10101         atomic_dec(&BTRFS_I(inode)->root->nr_swapfiles);
10102 }
10103
10104 static int btrfs_swap_activate(struct swap_info_struct *sis, struct file *file,
10105                                sector_t *span)
10106 {
10107         struct inode *inode = file_inode(file);
10108         struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
10109         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
10110         struct extent_state *cached_state = NULL;
10111         struct extent_map *em = NULL;
10112         struct btrfs_device *device = NULL;
10113         struct btrfs_swap_info bsi = {
10114                 .lowest_ppage = (sector_t)-1ULL,
10115         };
10116         int ret = 0;
10117         u64 isize;
10118         u64 start;
10119
10120         /*
10121          * If the swap file was just created, make sure delalloc is done. If the
10122          * file changes again after this, the user is doing something stupid and
10123          * we don't really care.
10124          */
10125         ret = btrfs_wait_ordered_range(inode, 0, (u64)-1);
10126         if (ret)
10127                 return ret;
10128
10129         /*
10130          * The inode is locked, so these flags won't change after we check them.
10131          */
10132         if (BTRFS_I(inode)->flags & BTRFS_INODE_COMPRESS) {
10133                 btrfs_warn(fs_info, "swapfile must not be compressed");
10134                 return -EINVAL;
10135         }
10136         if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW)) {
10137                 btrfs_warn(fs_info, "swapfile must not be copy-on-write");
10138                 return -EINVAL;
10139         }
10140         if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) {
10141                 btrfs_warn(fs_info, "swapfile must not be checksummed");
10142                 return -EINVAL;
10143         }
10144
10145         /*
10146          * Balance or device remove/replace/resize can move stuff around from
10147          * under us. The EXCL_OP flag makes sure they aren't running/won't run
10148          * concurrently while we are mapping the swap extents, and
10149          * fs_info->swapfile_pins prevents them from running while the swap file
10150          * is active and moving the extents. Note that this also prevents a
10151          * concurrent device add which isn't actually necessary, but it's not
10152          * really worth the trouble to allow it.
10153          */
10154         if (test_and_set_bit(BTRFS_FS_EXCL_OP, &fs_info->flags)) {
10155                 btrfs_warn(fs_info,
10156            "cannot activate swapfile while exclusive operation is running");
10157                 return -EBUSY;
10158         }
10159         /*
10160          * Snapshots can create extents which require COW even if NODATACOW is
10161          * set. We use this counter to prevent snapshots. We must increment it
10162          * before walking the extents because we don't want a concurrent
10163          * snapshot to run after we've already checked the extents.
10164          */
10165         atomic_inc(&BTRFS_I(inode)->root->nr_swapfiles);
10166
10167         isize = ALIGN_DOWN(inode->i_size, fs_info->sectorsize);
10168
10169         lock_extent_bits(io_tree, 0, isize - 1, &cached_state);
10170         start = 0;
10171         while (start < isize) {
10172                 u64 logical_block_start, physical_block_start;
10173                 struct btrfs_block_group *bg;
10174                 u64 len = isize - start;
10175
10176                 em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, start, len);
10177                 if (IS_ERR(em)) {
10178                         ret = PTR_ERR(em);
10179                         goto out;
10180                 }
10181
10182                 if (em->block_start == EXTENT_MAP_HOLE) {
10183                         btrfs_warn(fs_info, "swapfile must not have holes");
10184                         ret = -EINVAL;
10185                         goto out;
10186                 }
10187                 if (em->block_start == EXTENT_MAP_INLINE) {
10188                         /*
10189                          * It's unlikely we'll ever actually find ourselves
10190                          * here, as a file small enough to fit inline won't be
10191                          * big enough to store more than the swap header, but in
10192                          * case something changes in the future, let's catch it
10193                          * here rather than later.
10194                          */
10195                         btrfs_warn(fs_info, "swapfile must not be inline");
10196                         ret = -EINVAL;
10197                         goto out;
10198                 }
10199                 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
10200                         btrfs_warn(fs_info, "swapfile must not be compressed");
10201                         ret = -EINVAL;
10202                         goto out;
10203                 }
10204
10205                 logical_block_start = em->block_start + (start - em->start);
10206                 len = min(len, em->len - (start - em->start));
10207                 free_extent_map(em);
10208                 em = NULL;
10209
10210                 ret = can_nocow_extent(inode, start, &len, NULL, NULL, NULL);
10211                 if (ret < 0) {
10212                         goto out;
10213                 } else if (ret) {
10214                         ret = 0;
10215                 } else {
10216                         btrfs_warn(fs_info,
10217                                    "swapfile must not be copy-on-write");
10218                         ret = -EINVAL;
10219                         goto out;
10220                 }
10221
10222                 em = btrfs_get_chunk_map(fs_info, logical_block_start, len);
10223                 if (IS_ERR(em)) {
10224                         ret = PTR_ERR(em);
10225                         goto out;
10226                 }
10227
10228                 if (em->map_lookup->type & BTRFS_BLOCK_GROUP_PROFILE_MASK) {
10229                         btrfs_warn(fs_info,
10230                                    "swapfile must have single data profile");
10231                         ret = -EINVAL;
10232                         goto out;
10233                 }
10234
10235                 if (device == NULL) {
10236                         device = em->map_lookup->stripes[0].dev;
10237                         ret = btrfs_add_swapfile_pin(inode, device, false);
10238                         if (ret == 1)
10239                                 ret = 0;
10240                         else if (ret)
10241                                 goto out;
10242                 } else if (device != em->map_lookup->stripes[0].dev) {
10243                         btrfs_warn(fs_info, "swapfile must be on one device");
10244                         ret = -EINVAL;
10245                         goto out;
10246                 }
10247
10248                 physical_block_start = (em->map_lookup->stripes[0].physical +
10249                                         (logical_block_start - em->start));
10250                 len = min(len, em->len - (logical_block_start - em->start));
10251                 free_extent_map(em);
10252                 em = NULL;
10253
10254                 bg = btrfs_lookup_block_group(fs_info, logical_block_start);
10255                 if (!bg) {
10256                         btrfs_warn(fs_info,
10257                            "could not find block group containing swapfile");
10258                         ret = -EINVAL;
10259                         goto out;
10260                 }
10261
10262                 ret = btrfs_add_swapfile_pin(inode, bg, true);
10263                 if (ret) {
10264                         btrfs_put_block_group(bg);
10265                         if (ret == 1)
10266                                 ret = 0;
10267                         else
10268                                 goto out;
10269                 }
10270
10271                 if (bsi.block_len &&
10272                     bsi.block_start + bsi.block_len == physical_block_start) {
10273                         bsi.block_len += len;
10274                 } else {
10275                         if (bsi.block_len) {
10276                                 ret = btrfs_add_swap_extent(sis, &bsi);
10277                                 if (ret)
10278                                         goto out;
10279                         }
10280                         bsi.start = start;
10281                         bsi.block_start = physical_block_start;
10282                         bsi.block_len = len;
10283                 }
10284
10285                 start += len;
10286         }
10287
10288         if (bsi.block_len)
10289                 ret = btrfs_add_swap_extent(sis, &bsi);
10290
10291 out:
10292         if (!IS_ERR_OR_NULL(em))
10293                 free_extent_map(em);
10294
10295         unlock_extent_cached(io_tree, 0, isize - 1, &cached_state);
10296
10297         if (ret)
10298                 btrfs_swap_deactivate(file);
10299
10300         clear_bit(BTRFS_FS_EXCL_OP, &fs_info->flags);
10301
10302         if (ret)
10303                 return ret;
10304
10305         if (device)
10306                 sis->bdev = device->bdev;
10307         *span = bsi.highest_ppage - bsi.lowest_ppage + 1;
10308         sis->max = bsi.nr_pages;
10309         sis->pages = bsi.nr_pages - 1;
10310         sis->highest_bit = bsi.nr_pages - 1;
10311         return bsi.nr_extents;
10312 }
10313 #else
10314 static void btrfs_swap_deactivate(struct file *file)
10315 {
10316 }
10317
10318 static int btrfs_swap_activate(struct swap_info_struct *sis, struct file *file,
10319                                sector_t *span)
10320 {
10321         return -EOPNOTSUPP;
10322 }
10323 #endif
10324
10325 static const struct inode_operations btrfs_dir_inode_operations = {
10326         .getattr        = btrfs_getattr,
10327         .lookup         = btrfs_lookup,
10328         .create         = btrfs_create,
10329         .unlink         = btrfs_unlink,
10330         .link           = btrfs_link,
10331         .mkdir          = btrfs_mkdir,
10332         .rmdir          = btrfs_rmdir,
10333         .rename         = btrfs_rename2,
10334         .symlink        = btrfs_symlink,
10335         .setattr        = btrfs_setattr,
10336         .mknod          = btrfs_mknod,
10337         .listxattr      = btrfs_listxattr,
10338         .permission     = btrfs_permission,
10339         .get_acl        = btrfs_get_acl,
10340         .set_acl        = btrfs_set_acl,
10341         .update_time    = btrfs_update_time,
10342         .tmpfile        = btrfs_tmpfile,
10343 };
10344
10345 static const struct file_operations btrfs_dir_file_operations = {
10346         .llseek         = generic_file_llseek,
10347         .read           = generic_read_dir,
10348         .iterate_shared = btrfs_real_readdir,
10349         .open           = btrfs_opendir,
10350         .unlocked_ioctl = btrfs_ioctl,
10351 #ifdef CONFIG_COMPAT
10352         .compat_ioctl   = btrfs_compat_ioctl,
10353 #endif
10354         .release        = btrfs_release_file,
10355         .fsync          = btrfs_sync_file,
10356 };
10357
10358 static const struct extent_io_ops btrfs_extent_io_ops = {
10359         /* mandatory callbacks */
10360         .submit_bio_hook = btrfs_submit_bio_hook,
10361         .readpage_end_io_hook = btrfs_readpage_end_io_hook,
10362 };
10363
10364 /*
10365  * btrfs doesn't support the bmap operation because swapfiles
10366  * use bmap to make a mapping of extents in the file.  They assume
10367  * these extents won't change over the life of the file and they
10368  * use the bmap result to do IO directly to the drive.
10369  *
10370  * the btrfs bmap call would return logical addresses that aren't
10371  * suitable for IO and they also will change frequently as COW
10372  * operations happen.  So, swapfile + btrfs == corruption.
10373  *
10374  * For now we're avoiding this by dropping bmap.
10375  */
10376 static const struct address_space_operations btrfs_aops = {
10377         .readpage       = btrfs_readpage,
10378         .writepage      = btrfs_writepage,
10379         .writepages     = btrfs_writepages,
10380         .readpages      = btrfs_readpages,
10381         .direct_IO      = btrfs_direct_IO,
10382         .invalidatepage = btrfs_invalidatepage,
10383         .releasepage    = btrfs_releasepage,
10384         .set_page_dirty = btrfs_set_page_dirty,
10385         .error_remove_page = generic_error_remove_page,
10386         .swap_activate  = btrfs_swap_activate,
10387         .swap_deactivate = btrfs_swap_deactivate,
10388 };
10389
10390 static const struct inode_operations btrfs_file_inode_operations = {
10391         .getattr        = btrfs_getattr,
10392         .setattr        = btrfs_setattr,
10393         .listxattr      = btrfs_listxattr,
10394         .permission     = btrfs_permission,
10395         .fiemap         = btrfs_fiemap,
10396         .get_acl        = btrfs_get_acl,
10397         .set_acl        = btrfs_set_acl,
10398         .update_time    = btrfs_update_time,
10399 };
10400 static const struct inode_operations btrfs_special_inode_operations = {
10401         .getattr        = btrfs_getattr,
10402         .setattr        = btrfs_setattr,
10403         .permission     = btrfs_permission,
10404         .listxattr      = btrfs_listxattr,
10405         .get_acl        = btrfs_get_acl,
10406         .set_acl        = btrfs_set_acl,
10407         .update_time    = btrfs_update_time,
10408 };
10409 static const struct inode_operations btrfs_symlink_inode_operations = {
10410         .get_link       = page_get_link,
10411         .getattr        = btrfs_getattr,
10412         .setattr        = btrfs_setattr,
10413         .permission     = btrfs_permission,
10414         .listxattr      = btrfs_listxattr,
10415         .update_time    = btrfs_update_time,
10416 };
10417
10418 const struct dentry_operations btrfs_dentry_operations = {
10419         .d_delete       = btrfs_dentry_delete,
10420 };