fs/ext4/extents.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
   4  * Written by Alex Tomas <alex@clusterfs.com>
   5  *
   6  * Architecture independence:
   7  *   Copyright (c) 2005, Bull S.A.
   8  *   Written by Pierre Peiffer <pierre.peiffer@bull.net>
   9  */
  10
  11 /*
  12  * Extents support for EXT4
  13  *
  14  * TODO:
  15  *   - ext4*_error() should be used in some situations
  16  *   - analyze all BUG()/BUG_ON(), use -EIO where appropriate
  17  *   - smart tree reduction
  18  */
  19
  20 #include <linux/fs.h>
  21 #include <linux/time.h>
  22 #include <linux/jbd2.h>
  23 #include <linux/highuid.h>
  24 #include <linux/pagemap.h>
  25 #include <linux/quotaops.h>
  26 #include <linux/string.h>
  27 #include <linux/slab.h>
  28 #include <linux/uaccess.h>
  29 #include <linux/fiemap.h>
  30 #include <linux/backing-dev.h>
  31 #include "ext4_jbd2.h"
  32 #include "ext4_extents.h"
  33 #include "xattr.h"
  34
  35 #include <trace/events/ext4.h>
  36
  37 /*
  38  * used by extent splitting.
  39  */
  40 #define EXT4_EXT_MAY_ZEROOUT    0x1  /* safe to zeroout if split fails \
  41                                         due to ENOSPC */
  42 #define EXT4_EXT_MARK_UNWRIT1   0x2  /* mark first half unwritten */
  43 #define EXT4_EXT_MARK_UNWRIT2   0x4  /* mark second half unwritten */
  44
  45 #define EXT4_EXT_DATA_VALID1    0x8  /* first half contains valid data */
  46 #define EXT4_EXT_DATA_VALID2    0x10 /* second half contains valid data */
  47
  48 static __le32 ext4_extent_block_csum(struct inode *inode,
  49                                      struct ext4_extent_header *eh)
  50 {
  51         struct ext4_inode_info *ei = EXT4_I(inode);
  52         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
  53         __u32 csum;
  54
  55         csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)eh,
  56                            EXT4_EXTENT_TAIL_OFFSET(eh));
  57         return cpu_to_le32(csum);
  58 }
  59
  60 static int ext4_extent_block_csum_verify(struct inode *inode,
  61                                          struct ext4_extent_header *eh)
  62 {
  63         struct ext4_extent_tail *et;
  64
  65         if (!ext4_has_metadata_csum(inode->i_sb))
  66                 return 1;
  67
  68         et = find_ext4_extent_tail(eh);
  69         if (et->et_checksum != ext4_extent_block_csum(inode, eh))
  70                 return 0;
  71         return 1;
  72 }
  73
  74 static void ext4_extent_block_csum_set(struct inode *inode,
  75                                        struct ext4_extent_header *eh)
  76 {
  77         struct ext4_extent_tail *et;
  78
  79         if (!ext4_has_metadata_csum(inode->i_sb))
  80                 return;
  81
  82         et = find_ext4_extent_tail(eh);
  83         et->et_checksum = ext4_extent_block_csum(inode, eh);
  84 }
  85
  86 static int ext4_split_extent(handle_t *handle,
  87                                 struct inode *inode,
  88                                 struct ext4_ext_path **ppath,
  89                                 struct ext4_map_blocks *map,
  90                                 int split_flag,
  91                                 int flags);
  92
  93 static int ext4_split_extent_at(handle_t *handle,
  94                              struct inode *inode,
  95                              struct ext4_ext_path **ppath,
  96                              ext4_lblk_t split,
  97                              int split_flag,
  98                              int flags);
  99
 100 static int ext4_find_delayed_extent(struct inode *inode,
 101                                     struct extent_status *newes);
 102
 103 static int ext4_ext_trunc_restart_fn(struct inode *inode, int *dropped)
 104 {
 105         /*
 106          * Drop i_data_sem to avoid deadlock with ext4_map_blocks.  At this
 107          * moment, get_block can be called only for blocks inside i_size since
 108          * page cache has been already dropped and writes are blocked by
 109          * i_mutex. So we can safely drop the i_data_sem here.
 110          */
 111         BUG_ON(EXT4_JOURNAL(inode) == NULL);
 112         ext4_discard_preallocations(inode);
 113         up_write(&EXT4_I(inode)->i_data_sem);
 114         *dropped = 1;
 115         return 0;
 116 }
 117
 118 /*
 119  * Make sure 'handle' has at least 'check_cred' credits. If not, restart
 120  * transaction with 'restart_cred' credits. The function drops i_data_sem
 121  * when restarting transaction and gets it after transaction is restarted.
 122  *
 123  * The function returns 0 on success, 1 if transaction had to be restarted,
 124  * and < 0 in case of fatal error.
 125  */
 126 int ext4_datasem_ensure_credits(handle_t *handle, struct inode *inode,
 127                                 int check_cred, int restart_cred,
 128                                 int revoke_cred)
 129 {
 130         int ret;
 131         int dropped = 0;
 132
 133         ret = ext4_journal_ensure_credits_fn(handle, check_cred, restart_cred,
 134                 revoke_cred, ext4_ext_trunc_restart_fn(inode, &dropped));
 135         if (dropped)
 136                 down_write(&EXT4_I(inode)->i_data_sem);
 137         return ret;
 138 }
 139
 140 /*
 141  * could return:
 142  *  - EROFS
 143  *  - ENOMEM
 144  */
 145 static int ext4_ext_get_access(handle_t *handle, struct inode *inode,
 146                                 struct ext4_ext_path *path)
 147 {
 148         if (path->p_bh) {
 149                 /* path points to block */
 150                 BUFFER_TRACE(path->p_bh, "get_write_access");
 151                 return ext4_journal_get_write_access(handle, path->p_bh);
 152         }
 153         /* path points to leaf/index in inode body */
 154         /* we use in-core data, no need to protect them */
 155         return 0;
 156 }
 157
 158 /*
 159  * could return:
 160  *  - EROFS
 161  *  - ENOMEM
 162  *  - EIO
 163  */
 164 static int __ext4_ext_dirty(const char *where, unsigned int line,
 165                             handle_t *handle, struct inode *inode,
 166                             struct ext4_ext_path *path)
 167 {
 168         int err;
 169
 170         WARN_ON(!rwsem_is_locked(&EXT4_I(inode)->i_data_sem));
 171         if (path->p_bh) {
 172                 ext4_extent_block_csum_set(inode, ext_block_hdr(path->p_bh));
 173                 /* path points to block */
 174                 err = __ext4_handle_dirty_metadata(where, line, handle,
 175                                                    inode, path->p_bh);
 176         } else {
 177                 /* path points to leaf/index in inode body */
 178                 err = ext4_mark_inode_dirty(handle, inode);
 179         }
 180         return err;
 181 }
 182
 183 #define ext4_ext_dirty(handle, inode, path) \
 184                 __ext4_ext_dirty(__func__, __LINE__, (handle), (inode), (path))
 185
 186 static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
 187                               struct ext4_ext_path *path,
 188                               ext4_lblk_t block)
 189 {
 190         if (path) {
 191                 int depth = path->p_depth;
 192                 struct ext4_extent *ex;
 193
 194                 /*
 195                  * Try to predict block placement assuming that we are
 196                  * filling in a file which will eventually be
 197                  * non-sparse --- i.e., in the case of libbfd writing
 198                  * an ELF object sections out-of-order but in a way
 199                  * the eventually results in a contiguous object or
 200                  * executable file, or some database extending a table
 201                  * space file.  However, this is actually somewhat
 202                  * non-ideal if we are writing a sparse file such as
 203                  * qemu or KVM writing a raw image file that is going
 204                  * to stay fairly sparse, since it will end up
 205                  * fragmenting the file system's free space.  Maybe we
 206                  * should have some hueristics or some way to allow
 207                  * userspace to pass a hint to file system,
 208                  * especially if the latter case turns out to be
 209                  * common.
 210                  */
 211                 ex = path[depth].p_ext;
 212                 if (ex) {
 213                         ext4_fsblk_t ext_pblk = ext4_ext_pblock(ex);
 214                         ext4_lblk_t ext_block = le32_to_cpu(ex->ee_block);
 215
 216                         if (block > ext_block)
 217                                 return ext_pblk + (block - ext_block);
 218                         else
 219                                 return ext_pblk - (ext_block - block);
 220                 }
 221
 222                 /* it looks like index is empty;
 223                  * try to find starting block from index itself */
 224                 if (path[depth].p_bh)
 225                         return path[depth].p_bh->b_blocknr;
 226         }
 227
 228         /* OK. use inode's group */
 229         return ext4_inode_to_goal_block(inode);
 230 }
 231
 232 /*
 233  * Allocation for a meta data block
 234  */
 235 static ext4_fsblk_t
 236 ext4_ext_new_meta_block(handle_t *handle, struct inode *inode,
 237                         struct ext4_ext_path *path,
 238                         struct ext4_extent *ex, int *err, unsigned int flags)
 239 {
 240         ext4_fsblk_t goal, newblock;
 241
 242         goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block));
 243         newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
 244                                         NULL, err);
 245         return newblock;
 246 }
 247
 248 static inline int ext4_ext_space_block(struct inode *inode, int check)
 249 {
 250         int size;
 251
 252         size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 253                         / sizeof(struct ext4_extent);
 254 #ifdef AGGRESSIVE_TEST
 255         if (!check && size > 6)
 256                 size = 6;
 257 #endif
 258         return size;
 259 }
 260
 261 static inline int ext4_ext_space_block_idx(struct inode *inode, int check)
 262 {
 263         int size;
 264
 265         size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 266                         / sizeof(struct ext4_extent_idx);
 267 #ifdef AGGRESSIVE_TEST
 268         if (!check && size > 5)
 269                 size = 5;
 270 #endif
 271         return size;
 272 }
 273
 274 static inline int ext4_ext_space_root(struct inode *inode, int check)
 275 {
 276         int size;
 277
 278         size = sizeof(EXT4_I(inode)->i_data);
 279         size -= sizeof(struct ext4_extent_header);
 280         size /= sizeof(struct ext4_extent);
 281 #ifdef AGGRESSIVE_TEST
 282         if (!check && size > 3)
 283                 size = 3;
 284 #endif
 285         return size;
 286 }
 287
 288 static inline int ext4_ext_space_root_idx(struct inode *inode, int check)
 289 {
 290         int size;
 291
 292         size = sizeof(EXT4_I(inode)->i_data);
 293         size -= sizeof(struct ext4_extent_header);
 294         size /= sizeof(struct ext4_extent_idx);
 295 #ifdef AGGRESSIVE_TEST
 296         if (!check && size > 4)
 297                 size = 4;
 298 #endif
 299         return size;
 300 }
 301
 302 static inline int
 303 ext4_force_split_extent_at(handle_t *handle, struct inode *inode,
 304                            struct ext4_ext_path **ppath, ext4_lblk_t lblk,
 305                            int nofail)
 306 {
 307         struct ext4_ext_path *path = *ppath;
 308         int unwritten = ext4_ext_is_unwritten(path[path->p_depth].p_ext);
 309
 310         return ext4_split_extent_at(handle, inode, ppath, lblk, unwritten ?
 311                         EXT4_EXT_MARK_UNWRIT1|EXT4_EXT_MARK_UNWRIT2 : 0,
 312                         EXT4_EX_NOCACHE | EXT4_GET_BLOCKS_PRE_IO |
 313                         (nofail ? EXT4_GET_BLOCKS_METADATA_NOFAIL:0));
 314 }
 315
 316 static int
 317 ext4_ext_max_entries(struct inode *inode, int depth)
 318 {
 319         int max;
 320
 321         if (depth == ext_depth(inode)) {
 322                 if (depth == 0)
 323                         max = ext4_ext_space_root(inode, 1);
 324                 else
 325                         max = ext4_ext_space_root_idx(inode, 1);
 326         } else {
 327                 if (depth == 0)
 328                         max = ext4_ext_space_block(inode, 1);
 329                 else
 330                         max = ext4_ext_space_block_idx(inode, 1);
 331         }
 332
 333         return max;
 334 }
 335
 336 static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext)
 337 {
 338         ext4_fsblk_t block = ext4_ext_pblock(ext);
 339         int len = ext4_ext_get_actual_len(ext);
 340         ext4_lblk_t lblock = le32_to_cpu(ext->ee_block);
 341
 342         /*
 343          * We allow neither:
 344          *  - zero length
 345          *  - overflow/wrap-around
 346          */
 347         if (lblock + len <= lblock)
 348                 return 0;
 349         return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, len);
 350 }
 351
 352 static int ext4_valid_extent_idx(struct inode *inode,
 353                                 struct ext4_extent_idx *ext_idx)
 354 {
 355         ext4_fsblk_t block = ext4_idx_pblock(ext_idx);
 356
 357         return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, 1);
 358 }
 359
 360 static int ext4_valid_extent_entries(struct inode *inode,
 361                                 struct ext4_extent_header *eh,
 362                                 int depth)
 363 {
 364         unsigned short entries;
 365         if (eh->eh_entries == 0)
 366                 return 1;
 367
 368         entries = le16_to_cpu(eh->eh_entries);
 369
 370         if (depth == 0) {
 371                 /* leaf entries */
 372                 struct ext4_extent *ext = EXT_FIRST_EXTENT(eh);
 373                 struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
 374                 ext4_fsblk_t pblock = 0;
 375                 ext4_lblk_t lblock = 0;
 376                 ext4_lblk_t prev = 0;
 377                 int len = 0;
 378                 while (entries) {
 379                         if (!ext4_valid_extent(inode, ext))
 380                                 return 0;
 381
 382                         /* Check for overlapping extents */
 383                         lblock = le32_to_cpu(ext->ee_block);
 384                         len = ext4_ext_get_actual_len(ext);
 385                         if ((lblock <= prev) && prev) {
 386                                 pblock = ext4_ext_pblock(ext);
 387                                 es->s_last_error_block = cpu_to_le64(pblock);
 388                                 return 0;
 389                         }
 390                         ext++;
 391                         entries--;
 392                         prev = lblock + len - 1;
 393                 }
 394         } else {
 395                 struct ext4_extent_idx *ext_idx = EXT_FIRST_INDEX(eh);
 396                 while (entries) {
 397                         if (!ext4_valid_extent_idx(inode, ext_idx))
 398                                 return 0;
 399                         ext_idx++;
 400                         entries--;
 401                 }
 402         }
 403         return 1;
 404 }
 405
 406 static int __ext4_ext_check(const char *function, unsigned int line,
 407                             struct inode *inode, struct ext4_extent_header *eh,
 408                             int depth, ext4_fsblk_t pblk)
 409 {
 410         const char *error_msg;
 411         int max = 0, err = -EFSCORRUPTED;
 412
 413         if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) {
 414                 error_msg = "invalid magic";
 415                 goto corrupted;
 416         }
 417         if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) {
 418                 error_msg = "unexpected eh_depth";
 419                 goto corrupted;
 420         }
 421         if (unlikely(eh->eh_max == 0)) {
 422                 error_msg = "invalid eh_max";
 423                 goto corrupted;
 424         }
 425         max = ext4_ext_max_entries(inode, depth);
 426         if (unlikely(le16_to_cpu(eh->eh_max) > max)) {
 427                 error_msg = "too large eh_max";
 428                 goto corrupted;
 429         }
 430         if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) {
 431                 error_msg = "invalid eh_entries";
 432                 goto corrupted;
 433         }
 434         if (!ext4_valid_extent_entries(inode, eh, depth)) {
 435                 error_msg = "invalid extent entries";
 436                 goto corrupted;
 437         }
 438         if (unlikely(depth > 32)) {
 439                 error_msg = "too large eh_depth";
 440                 goto corrupted;
 441         }
 442         /* Verify checksum on non-root extent tree nodes */
 443         if (ext_depth(inode) != depth &&
 444             !ext4_extent_block_csum_verify(inode, eh)) {
 445                 error_msg = "extent tree corrupted";
 446                 err = -EFSBADCRC;
 447                 goto corrupted;
 448         }
 449         return 0;
 450
 451 corrupted:
 452         ext4_set_errno(inode->i_sb, -err);
 453         ext4_error_inode(inode, function, line, 0,
 454                          "pblk %llu bad header/extent: %s - magic %x, "
 455                          "entries %u, max %u(%u), depth %u(%u)",
 456                          (unsigned long long) pblk, error_msg,
 457                          le16_to_cpu(eh->eh_magic),
 458                          le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max),
 459                          max, le16_to_cpu(eh->eh_depth), depth);
 460         return err;
 461 }
 462
 463 #define ext4_ext_check(inode, eh, depth, pblk)                  \
 464         __ext4_ext_check(__func__, __LINE__, (inode), (eh), (depth), (pblk))
 465
 466 int ext4_ext_check_inode(struct inode *inode)
 467 {
 468         return ext4_ext_check(inode, ext_inode_hdr(inode), ext_depth(inode), 0);
 469 }
 470
 471 static struct buffer_head *
 472 __read_extent_tree_block(const char *function, unsigned int line,
 473                          struct inode *inode, ext4_fsblk_t pblk, int depth,
 474                          int flags)
 475 {
 476         struct buffer_head              *bh;
 477         int                             err;
 478
 479         bh = sb_getblk_gfp(inode->i_sb, pblk, __GFP_MOVABLE | GFP_NOFS);
 480         if (unlikely(!bh))
 481                 return ERR_PTR(-ENOMEM);
 482
 483         if (!bh_uptodate_or_lock(bh)) {
 484                 trace_ext4_ext_load_extent(inode, pblk, _RET_IP_);
 485                 err = bh_submit_read(bh);
 486                 if (err < 0)
 487                         goto errout;
 488         }
 489         if (buffer_verified(bh) && !(flags & EXT4_EX_FORCE_CACHE))
 490                 return bh;
 491         if (!ext4_has_feature_journal(inode->i_sb) ||
 492             (inode->i_ino !=
 493              le32_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_journal_inum))) {
 494                 err = __ext4_ext_check(function, line, inode,
 495                                        ext_block_hdr(bh), depth, pblk);
 496                 if (err)
 497                         goto errout;
 498         }
 499         set_buffer_verified(bh);
 500         /*
 501          * If this is a leaf block, cache all of its entries
 502          */
 503         if (!(flags & EXT4_EX_NOCACHE) && depth == 0) {
 504                 struct ext4_extent_header *eh = ext_block_hdr(bh);
 505                 struct ext4_extent *ex = EXT_FIRST_EXTENT(eh);
 506                 ext4_lblk_t prev = 0;
 507                 int i;
 508
 509                 for (i = le16_to_cpu(eh->eh_entries); i > 0; i--, ex++) {
 510                         unsigned int status = EXTENT_STATUS_WRITTEN;
 511                         ext4_lblk_t lblk = le32_to_cpu(ex->ee_block);
 512                         int len = ext4_ext_get_actual_len(ex);
 513
 514                         if (prev && (prev != lblk))
 515                                 ext4_es_cache_extent(inode, prev,
 516                                                      lblk - prev, ~0,
 517                                                      EXTENT_STATUS_HOLE);
 518
 519                         if (ext4_ext_is_unwritten(ex))
 520                                 status = EXTENT_STATUS_UNWRITTEN;
 521                         ext4_es_cache_extent(inode, lblk, len,
 522                                              ext4_ext_pblock(ex), status);
 523                         prev = lblk + len;
 524                 }
 525         }
 526         return bh;
 527 errout:
 528         put_bh(bh);
 529         return ERR_PTR(err);
 530
 531 }
 532
 533 #define read_extent_tree_block(inode, pblk, depth, flags)               \
 534         __read_extent_tree_block(__func__, __LINE__, (inode), (pblk),   \
 535                                  (depth), (flags))
 536
 537 /*
 538  * This function is called to cache a file's extent information in the
 539  * extent status tree
 540  */
 541 int ext4_ext_precache(struct inode *inode)
 542 {
 543         struct ext4_inode_info *ei = EXT4_I(inode);
 544         struct ext4_ext_path *path = NULL;
 545         struct buffer_head *bh;
 546         int i = 0, depth, ret = 0;
 547
 548         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
 549                 return 0;       /* not an extent-mapped inode */
 550
 551         down_read(&ei->i_data_sem);
 552         depth = ext_depth(inode);
 553
 554         path = kcalloc(depth + 1, sizeof(struct ext4_ext_path),
 555                        GFP_NOFS);
 556         if (path == NULL) {
 557                 up_read(&ei->i_data_sem);
 558                 return -ENOMEM;
 559         }
 560
 561         /* Don't cache anything if there are no external extent blocks */
 562         if (depth == 0)
 563                 goto out;
 564         path[0].p_hdr = ext_inode_hdr(inode);
 565         ret = ext4_ext_check(inode, path[0].p_hdr, depth, 0);
 566         if (ret)
 567                 goto out;
 568         path[0].p_idx = EXT_FIRST_INDEX(path[0].p_hdr);
 569         while (i >= 0) {
 570                 /*
 571                  * If this is a leaf block or we've reached the end of
 572                  * the index block, go up
 573                  */
 574                 if ((i == depth) ||
 575                     path[i].p_idx > EXT_LAST_INDEX(path[i].p_hdr)) {
 576                         brelse(path[i].p_bh);
 577                         path[i].p_bh = NULL;
 578                         i--;
 579                         continue;
 580                 }
 581                 bh = read_extent_tree_block(inode,
 582                                             ext4_idx_pblock(path[i].p_idx++),
 583                                             depth - i - 1,
 584                                             EXT4_EX_FORCE_CACHE);
 585                 if (IS_ERR(bh)) {
 586                         ret = PTR_ERR(bh);
 587                         break;
 588                 }
 589                 i++;
 590                 path[i].p_bh = bh;
 591                 path[i].p_hdr = ext_block_hdr(bh);
 592                 path[i].p_idx = EXT_FIRST_INDEX(path[i].p_hdr);
 593         }
 594         ext4_set_inode_state(inode, EXT4_STATE_EXT_PRECACHED);
 595 out:
 596         up_read(&ei->i_data_sem);
 597         ext4_ext_drop_refs(path);
 598         kfree(path);
 599         return ret;
 600 }
 601
 602 #ifdef EXT_DEBUG
 603 static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
 604 {
 605         int k, l = path->p_depth;
 606
 607         ext_debug("path:");
 608         for (k = 0; k <= l; k++, path++) {
 609                 if (path->p_idx) {
 610                   ext_debug("  %d->%llu", le32_to_cpu(path->p_idx->ei_block),
 611                             ext4_idx_pblock(path->p_idx));
 612                 } else if (path->p_ext) {
 613                         ext_debug("  %d:[%d]%d:%llu ",
 614                                   le32_to_cpu(path->p_ext->ee_block),
 615                                   ext4_ext_is_unwritten(path->p_ext),
 616                                   ext4_ext_get_actual_len(path->p_ext),
 617                                   ext4_ext_pblock(path->p_ext));
 618                 } else
 619                         ext_debug("  []");
 620         }
 621         ext_debug("\n");
 622 }
 623
 624 static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path)
 625 {
 626         int depth = ext_depth(inode);
 627         struct ext4_extent_header *eh;
 628         struct ext4_extent *ex;
 629         int i;
 630
 631         if (!path)
 632                 return;
 633
 634         eh = path[depth].p_hdr;
 635         ex = EXT_FIRST_EXTENT(eh);
 636
 637         ext_debug("Displaying leaf extents for inode %lu\n", inode->i_ino);
 638
 639         for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) {
 640                 ext_debug("%d:[%d]%d:%llu ", le32_to_cpu(ex->ee_block),
 641                           ext4_ext_is_unwritten(ex),
 642                           ext4_ext_get_actual_len(ex), ext4_ext_pblock(ex));
 643         }
 644         ext_debug("\n");
 645 }
 646
 647 static void ext4_ext_show_move(struct inode *inode, struct ext4_ext_path *path,
 648                         ext4_fsblk_t newblock, int level)
 649 {
 650         int depth = ext_depth(inode);
 651         struct ext4_extent *ex;
 652
 653         if (depth != level) {
 654                 struct ext4_extent_idx *idx;
 655                 idx = path[level].p_idx;
 656                 while (idx <= EXT_MAX_INDEX(path[level].p_hdr)) {
 657                         ext_debug("%d: move %d:%llu in new index %llu\n", level,
 658                                         le32_to_cpu(idx->ei_block),
 659                                         ext4_idx_pblock(idx),
 660                                         newblock);
 661                         idx++;
 662                 }
 663
 664                 return;
 665         }
 666
 667         ex = path[depth].p_ext;
 668         while (ex <= EXT_MAX_EXTENT(path[depth].p_hdr)) {
 669                 ext_debug("move %d:%llu:[%d]%d in new leaf %llu\n",
 670                                 le32_to_cpu(ex->ee_block),
 671                                 ext4_ext_pblock(ex),
 672                                 ext4_ext_is_unwritten(ex),
 673                                 ext4_ext_get_actual_len(ex),
 674                                 newblock);
 675                 ex++;
 676         }
 677 }
 678
 679 #else
 680 #define ext4_ext_show_path(inode, path)
 681 #define ext4_ext_show_leaf(inode, path)
 682 #define ext4_ext_show_move(inode, path, newblock, level)
 683 #endif
 684
 685 void ext4_ext_drop_refs(struct ext4_ext_path *path)
 686 {
 687         int depth, i;
 688
 689         if (!path)
 690                 return;
 691         depth = path->p_depth;
 692         for (i = 0; i <= depth; i++, path++)
 693                 if (path->p_bh) {
 694                         brelse(path->p_bh);
 695                         path->p_bh = NULL;
 696                 }
 697 }
 698
 699 /*
 700  * ext4_ext_binsearch_idx:
 701  * binary search for the closest index of the given block
 702  * the header must be checked before calling this
 703  */
 704 static void
 705 ext4_ext_binsearch_idx(struct inode *inode,
 706                         struct ext4_ext_path *path, ext4_lblk_t block)
 707 {
 708         struct ext4_extent_header *eh = path->p_hdr;
 709         struct ext4_extent_idx *r, *l, *m;
 710
 711
 712         ext_debug("binsearch for %u(idx):  ", block);
 713
 714         l = EXT_FIRST_INDEX(eh) + 1;
 715         r = EXT_LAST_INDEX(eh);
 716         while (l <= r) {
 717                 m = l + (r - l) / 2;
 718                 if (block < le32_to_cpu(m->ei_block))
 719                         r = m - 1;
 720                 else
 721                         l = m + 1;
 722                 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ei_block),
 723                                 m, le32_to_cpu(m->ei_block),
 724                                 r, le32_to_cpu(r->ei_block));
 725         }
 726
 727         path->p_idx = l - 1;
 728         ext_debug("  -> %u->%lld ", le32_to_cpu(path->p_idx->ei_block),
 729                   ext4_idx_pblock(path->p_idx));
 730
 731 #ifdef CHECK_BINSEARCH
 732         {
 733                 struct ext4_extent_idx *chix, *ix;
 734                 int k;
 735
 736                 chix = ix = EXT_FIRST_INDEX(eh);
 737                 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) {
 738                   if (k != 0 &&
 739                       le32_to_cpu(ix->ei_block) <= le32_to_cpu(ix[-1].ei_block)) {
 740                                 printk(KERN_DEBUG "k=%d, ix=0x%p, "
 741                                        "first=0x%p\n", k,
 742                                        ix, EXT_FIRST_INDEX(eh));
 743                                 printk(KERN_DEBUG "%u <= %u\n",
 744                                        le32_to_cpu(ix->ei_block),
 745                                        le32_to_cpu(ix[-1].ei_block));
 746                         }
 747                         BUG_ON(k && le32_to_cpu(ix->ei_block)
 748                                            <= le32_to_cpu(ix[-1].ei_block));
 749                         if (block < le32_to_cpu(ix->ei_block))
 750                                 break;
 751                         chix = ix;
 752                 }
 753                 BUG_ON(chix != path->p_idx);
 754         }
 755 #endif
 756
 757 }
 758
 759 /*
 760  * ext4_ext_binsearch:
 761  * binary search for closest extent of the given block
 762  * the header must be checked before calling this
 763  */
 764 static void
 765 ext4_ext_binsearch(struct inode *inode,
 766                 struct ext4_ext_path *path, ext4_lblk_t block)
 767 {
 768         struct ext4_extent_header *eh = path->p_hdr;
 769         struct ext4_extent *r, *l, *m;
 770
 771         if (eh->eh_entries == 0) {
 772                 /*
 773                  * this leaf is empty:
 774                  * we get such a leaf in split/add case
 775                  */
 776                 return;
 777         }
 778
 779         ext_debug("binsearch for %u:  ", block);
 780
 781         l = EXT_FIRST_EXTENT(eh) + 1;
 782         r = EXT_LAST_EXTENT(eh);
 783
 784         while (l <= r) {
 785                 m = l + (r - l) / 2;
 786                 if (block < le32_to_cpu(m->ee_block))
 787                         r = m - 1;
 788                 else
 789                         l = m + 1;
 790                 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ee_block),
 791                                 m, le32_to_cpu(m->ee_block),
 792                                 r, le32_to_cpu(r->ee_block));
 793         }
 794
 795         path->p_ext = l - 1;
 796         ext_debug("  -> %d:%llu:[%d]%d ",
 797                         le32_to_cpu(path->p_ext->ee_block),
 798                         ext4_ext_pblock(path->p_ext),
 799                         ext4_ext_is_unwritten(path->p_ext),
 800                         ext4_ext_get_actual_len(path->p_ext));
 801
 802 #ifdef CHECK_BINSEARCH
 803         {
 804                 struct ext4_extent *chex, *ex;
 805                 int k;
 806
 807                 chex = ex = EXT_FIRST_EXTENT(eh);
 808                 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) {
 809                         BUG_ON(k && le32_to_cpu(ex->ee_block)
 810                                           <= le32_to_cpu(ex[-1].ee_block));
 811                         if (block < le32_to_cpu(ex->ee_block))
 812                                 break;
 813                         chex = ex;
 814                 }
 815                 BUG_ON(chex != path->p_ext);
 816         }
 817 #endif
 818
 819 }
 820
 821 int ext4_ext_tree_init(handle_t *handle, struct inode *inode)
 822 {
 823         struct ext4_extent_header *eh;
 824
 825         eh = ext_inode_hdr(inode);
 826         eh->eh_depth = 0;
 827         eh->eh_entries = 0;
 828         eh->eh_magic = EXT4_EXT_MAGIC;
 829         eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode, 0));
 830         ext4_mark_inode_dirty(handle, inode);
 831         return 0;
 832 }
 833
 834 struct ext4_ext_path *
 835 ext4_find_extent(struct inode *inode, ext4_lblk_t block,
 836                  struct ext4_ext_path **orig_path, int flags)
 837 {
 838         struct ext4_extent_header *eh;
 839         struct buffer_head *bh;
 840         struct ext4_ext_path *path = orig_path ? *orig_path : NULL;
 841         short int depth, i, ppos = 0;
 842         int ret;
 843
 844         eh = ext_inode_hdr(inode);
 845         depth = ext_depth(inode);
 846         if (depth < 0 || depth > EXT4_MAX_EXTENT_DEPTH) {
 847                 EXT4_ERROR_INODE(inode, "inode has invalid extent depth: %d",
 848                                  depth);
 849                 ret = -EFSCORRUPTED;
 850                 goto err;
 851         }
 852
 853         if (path) {
 854                 ext4_ext_drop_refs(path);
 855                 if (depth > path[0].p_maxdepth) {
 856                         kfree(path);
 857                         *orig_path = path = NULL;
 858                 }
 859         }
 860         if (!path) {
 861                 /* account possible depth increase */
 862                 path = kcalloc(depth + 2, sizeof(struct ext4_ext_path),
 863                                 GFP_NOFS);
 864                 if (unlikely(!path))
 865                         return ERR_PTR(-ENOMEM);
 866                 path[0].p_maxdepth = depth + 1;
 867         }
 868         path[0].p_hdr = eh;
 869         path[0].p_bh = NULL;
 870
 871         i = depth;
 872         /* walk through the tree */
 873         while (i) {
 874                 ext_debug("depth %d: num %d, max %d\n",
 875                           ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
 876
 877                 ext4_ext_binsearch_idx(inode, path + ppos, block);
 878                 path[ppos].p_block = ext4_idx_pblock(path[ppos].p_idx);
 879                 path[ppos].p_depth = i;
 880                 path[ppos].p_ext = NULL;
 881
 882                 bh = read_extent_tree_block(inode, path[ppos].p_block, --i,
 883                                             flags);
 884                 if (IS_ERR(bh)) {
 885                         ret = PTR_ERR(bh);
 886                         goto err;
 887                 }
 888
 889                 eh = ext_block_hdr(bh);
 890                 ppos++;
 891                 path[ppos].p_bh = bh;
 892                 path[ppos].p_hdr = eh;
 893         }
 894
 895         path[ppos].p_depth = i;
 896         path[ppos].p_ext = NULL;
 897         path[ppos].p_idx = NULL;
 898
 899         /* find extent */
 900         ext4_ext_binsearch(inode, path + ppos, block);
 901         /* if not an empty leaf */
 902         if (path[ppos].p_ext)
 903                 path[ppos].p_block = ext4_ext_pblock(path[ppos].p_ext);
 904
 905         ext4_ext_show_path(inode, path);
 906
 907         return path;
 908
 909 err:
 910         ext4_ext_drop_refs(path);
 911         kfree(path);
 912         if (orig_path)
 913                 *orig_path = NULL;
 914         return ERR_PTR(ret);
 915 }
 916
 917 /*
 918  * ext4_ext_insert_index:
 919  * insert new index [@logical;@ptr] into the block at @curp;
 920  * check where to insert: before @curp or after @curp
 921  */
 922 static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
 923                                  struct ext4_ext_path *curp,
 924                                  int logical, ext4_fsblk_t ptr)
 925 {
 926         struct ext4_extent_idx *ix;
 927         int len, err;
 928
 929         err = ext4_ext_get_access(handle, inode, curp);
 930         if (err)
 931                 return err;
 932
 933         if (unlikely(logical == le32_to_cpu(curp->p_idx->ei_block))) {
 934                 EXT4_ERROR_INODE(inode,
 935                                  "logical %d == ei_block %d!",
 936                                  logical, le32_to_cpu(curp->p_idx->ei_block));
 937                 return -EFSCORRUPTED;
 938         }
 939
 940         if (unlikely(le16_to_cpu(curp->p_hdr->eh_entries)
 941                              >= le16_to_cpu(curp->p_hdr->eh_max))) {
 942                 EXT4_ERROR_INODE(inode,
 943                                  "eh_entries %d >= eh_max %d!",
 944                                  le16_to_cpu(curp->p_hdr->eh_entries),
 945                                  le16_to_cpu(curp->p_hdr->eh_max));
 946                 return -EFSCORRUPTED;
 947         }
 948
 949         if (logical > le32_to_cpu(curp->p_idx->ei_block)) {
 950                 /* insert after */
 951                 ext_debug("insert new index %d after: %llu\n", logical, ptr);
 952                 ix = curp->p_idx + 1;
 953         } else {
 954                 /* insert before */
 955                 ext_debug("insert new index %d before: %llu\n", logical, ptr);
 956                 ix = curp->p_idx;
 957         }
 958
 959         len = EXT_LAST_INDEX(curp->p_hdr) - ix + 1;
 960         BUG_ON(len < 0);
 961         if (len > 0) {
 962                 ext_debug("insert new index %d: "
 963                                 "move %d indices from 0x%p to 0x%p\n",
 964                                 logical, len, ix, ix + 1);
 965                 memmove(ix + 1, ix, len * sizeof(struct ext4_extent_idx));
 966         }
 967
 968         if (unlikely(ix > EXT_MAX_INDEX(curp->p_hdr))) {
 969                 EXT4_ERROR_INODE(inode, "ix > EXT_MAX_INDEX!");
 970                 return -EFSCORRUPTED;
 971         }
 972
 973         ix->ei_block = cpu_to_le32(logical);
 974         ext4_idx_store_pblock(ix, ptr);
 975         le16_add_cpu(&curp->p_hdr->eh_entries, 1);
 976
 977         if (unlikely(ix > EXT_LAST_INDEX(curp->p_hdr))) {
 978                 EXT4_ERROR_INODE(inode, "ix > EXT_LAST_INDEX!");
 979                 return -EFSCORRUPTED;
 980         }
 981
 982         err = ext4_ext_dirty(handle, inode, curp);
 983         ext4_std_error(inode->i_sb, err);
 984
 985         return err;
 986 }
 987
 988 /*
 989  * ext4_ext_split:
 990  * inserts new subtree into the path, using free index entry
 991  * at depth @at:
 992  * - allocates all needed blocks (new leaf and all intermediate index blocks)
 993  * - makes decision where to split
 994  * - moves remaining extents and index entries (right to the split point)
 995  *   into the newly allocated blocks
 996  * - initializes subtree
 997  */
 998 static int ext4_ext_split(handle_t *handle, struct inode *inode,
 999                           unsigned int flags,
1000                           struct ext4_ext_path *path,
1001                           struct ext4_extent *newext, int at)
1002 {
1003         struct buffer_head *bh = NULL;
1004         int depth = ext_depth(inode);
1005         struct ext4_extent_header *neh;
1006         struct ext4_extent_idx *fidx;
1007         int i = at, k, m, a;
1008         ext4_fsblk_t newblock, oldblock;
1009         __le32 border;
1010         ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */
1011         int err = 0;
1012         size_t ext_size = 0;
1013
1014         /* make decision: where to split? */
1015         /* FIXME: now decision is simplest: at current extent */
1016
1017         /* if current leaf will be split, then we should use
1018          * border from split point */
1019         if (unlikely(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr))) {
1020                 EXT4_ERROR_INODE(inode, "p_ext > EXT_MAX_EXTENT!");
1021                 return -EFSCORRUPTED;
1022         }
1023         if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) {
1024                 border = path[depth].p_ext[1].ee_block;
1025                 ext_debug("leaf will be split."
1026                                 " next leaf starts at %d\n",
1027                                   le32_to_cpu(border));
1028         } else {
1029                 border = newext->ee_block;
1030                 ext_debug("leaf will be added."
1031                                 " next leaf starts at %d\n",
1032                                 le32_to_cpu(border));
1033         }
1034
1035         /*
1036          * If error occurs, then we break processing
1037          * and mark filesystem read-only. index won't
1038          * be inserted and tree will be in consistent
1039          * state. Next mount will repair buffers too.
1040          */
1041
1042         /*
1043          * Get array to track all allocated blocks.
1044          * We need this to handle errors and free blocks
1045          * upon them.
1046          */
1047         ablocks = kcalloc(depth, sizeof(ext4_fsblk_t), GFP_NOFS);
1048         if (!ablocks)
1049                 return -ENOMEM;
1050
1051         /* allocate all needed blocks */
1052         ext_debug("allocate %d blocks for indexes/leaf\n", depth - at);
1053         for (a = 0; a < depth - at; a++) {
1054                 newblock = ext4_ext_new_meta_block(handle, inode, path,
1055                                                    newext, &err, flags);
1056                 if (newblock == 0)
1057                         goto cleanup;
1058                 ablocks[a] = newblock;
1059         }
1060
1061         /* initialize new leaf */
1062         newblock = ablocks[--a];
1063         if (unlikely(newblock == 0)) {
1064                 EXT4_ERROR_INODE(inode, "newblock == 0!");
1065                 err = -EFSCORRUPTED;
1066                 goto cleanup;
1067         }
1068         bh = sb_getblk_gfp(inode->i_sb, newblock, __GFP_MOVABLE | GFP_NOFS);
1069         if (unlikely(!bh)) {
1070                 err = -ENOMEM;
1071                 goto cleanup;
1072         }
1073         lock_buffer(bh);
1074
1075         err = ext4_journal_get_create_access(handle, bh);
1076         if (err)
1077                 goto cleanup;
1078
1079         neh = ext_block_hdr(bh);
1080         neh->eh_entries = 0;
1081         neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1082         neh->eh_magic = EXT4_EXT_MAGIC;
1083         neh->eh_depth = 0;
1084
1085         /* move remainder of path[depth] to the new leaf */
1086         if (unlikely(path[depth].p_hdr->eh_entries !=
1087                      path[depth].p_hdr->eh_max)) {
1088                 EXT4_ERROR_INODE(inode, "eh_entries %d != eh_max %d!",
1089                                  path[depth].p_hdr->eh_entries,
1090                                  path[depth].p_hdr->eh_max);
1091                 err = -EFSCORRUPTED;
1092                 goto cleanup;
1093         }
1094         /* start copy from next extent */
1095         m = EXT_MAX_EXTENT(path[depth].p_hdr) - path[depth].p_ext++;
1096         ext4_ext_show_move(inode, path, newblock, depth);
1097         if (m) {
1098                 struct ext4_extent *ex;
1099                 ex = EXT_FIRST_EXTENT(neh);
1100                 memmove(ex, path[depth].p_ext, sizeof(struct ext4_extent) * m);
1101                 le16_add_cpu(&neh->eh_entries, m);
1102         }
1103
1104         /* zero out unused area in the extent block */
1105         ext_size = sizeof(struct ext4_extent_header) +
1106                 sizeof(struct ext4_extent) * le16_to_cpu(neh->eh_entries);
1107         memset(bh->b_data + ext_size, 0, inode->i_sb->s_blocksize - ext_size);
1108         ext4_extent_block_csum_set(inode, neh);
1109         set_buffer_uptodate(bh);
1110         unlock_buffer(bh);
1111
1112         err = ext4_handle_dirty_metadata(handle, inode, bh);
1113         if (err)
1114                 goto cleanup;
1115         brelse(bh);
1116         bh = NULL;
1117
1118         /* correct old leaf */
1119         if (m) {
1120                 err = ext4_ext_get_access(handle, inode, path + depth);
1121                 if (err)
1122                         goto cleanup;
1123                 le16_add_cpu(&path[depth].p_hdr->eh_entries, -m);
1124                 err = ext4_ext_dirty(handle, inode, path + depth);
1125                 if (err)
1126                         goto cleanup;
1127
1128         }
1129
1130         /* create intermediate indexes */
1131         k = depth - at - 1;
1132         if (unlikely(k < 0)) {
1133                 EXT4_ERROR_INODE(inode, "k %d < 0!", k);
1134                 err = -EFSCORRUPTED;
1135                 goto cleanup;
1136         }
1137         if (k)
1138                 ext_debug("create %d intermediate indices\n", k);
1139         /* insert new index into current index block */
1140         /* current depth stored in i var */
1141         i = depth - 1;
1142         while (k--) {
1143                 oldblock = newblock;
1144                 newblock = ablocks[--a];
1145                 bh = sb_getblk(inode->i_sb, newblock);
1146                 if (unlikely(!bh)) {
1147                         err = -ENOMEM;
1148                         goto cleanup;
1149                 }
1150                 lock_buffer(bh);
1151
1152                 err = ext4_journal_get_create_access(handle, bh);
1153                 if (err)
1154                         goto cleanup;
1155
1156                 neh = ext_block_hdr(bh);
1157                 neh->eh_entries = cpu_to_le16(1);
1158                 neh->eh_magic = EXT4_EXT_MAGIC;
1159                 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1160                 neh->eh_depth = cpu_to_le16(depth - i);
1161                 fidx = EXT_FIRST_INDEX(neh);
1162                 fidx->ei_block = border;
1163                 ext4_idx_store_pblock(fidx, oldblock);
1164
1165                 ext_debug("int.index at %d (block %llu): %u -> %llu\n",
1166                                 i, newblock, le32_to_cpu(border), oldblock);
1167
1168                 /* move remainder of path[i] to the new index block */
1169                 if (unlikely(EXT_MAX_INDEX(path[i].p_hdr) !=
1170                                         EXT_LAST_INDEX(path[i].p_hdr))) {
1171                         EXT4_ERROR_INODE(inode,
1172                                          "EXT_MAX_INDEX != EXT_LAST_INDEX ee_block %d!",
1173                                          le32_to_cpu(path[i].p_ext->ee_block));
1174                         err = -EFSCORRUPTED;
1175                         goto cleanup;
1176                 }
1177                 /* start copy indexes */
1178                 m = EXT_MAX_INDEX(path[i].p_hdr) - path[i].p_idx++;
1179                 ext_debug("cur 0x%p, last 0x%p\n", path[i].p_idx,
1180                                 EXT_MAX_INDEX(path[i].p_hdr));
1181                 ext4_ext_show_move(inode, path, newblock, i);
1182                 if (m) {
1183                         memmove(++fidx, path[i].p_idx,
1184                                 sizeof(struct ext4_extent_idx) * m);
1185                         le16_add_cpu(&neh->eh_entries, m);
1186                 }
1187                 /* zero out unused area in the extent block */
1188                 ext_size = sizeof(struct ext4_extent_header) +
1189                    (sizeof(struct ext4_extent) * le16_to_cpu(neh->eh_entries));
1190                 memset(bh->b_data + ext_size, 0,
1191                         inode->i_sb->s_blocksize - ext_size);
1192                 ext4_extent_block_csum_set(inode, neh);
1193                 set_buffer_uptodate(bh);
1194                 unlock_buffer(bh);
1195
1196                 err = ext4_handle_dirty_metadata(handle, inode, bh);
1197                 if (err)
1198                         goto cleanup;
1199                 brelse(bh);
1200                 bh = NULL;
1201
1202                 /* correct old index */
1203                 if (m) {
1204                         err = ext4_ext_get_access(handle, inode, path + i);
1205                         if (err)
1206                                 goto cleanup;
1207                         le16_add_cpu(&path[i].p_hdr->eh_entries, -m);
1208                         err = ext4_ext_dirty(handle, inode, path + i);
1209                         if (err)
1210                                 goto cleanup;
1211                 }
1212
1213                 i--;
1214         }
1215
1216         /* insert new index */
1217         err = ext4_ext_insert_index(handle, inode, path + at,
1218                                     le32_to_cpu(border), newblock);
1219
1220 cleanup:
1221         if (bh) {
1222                 if (buffer_locked(bh))
1223                         unlock_buffer(bh);
1224                 brelse(bh);
1225         }
1226
1227         if (err) {
1228                 /* free all allocated blocks in error case */
1229                 for (i = 0; i < depth; i++) {
1230                         if (!ablocks[i])
1231                                 continue;
1232                         ext4_free_blocks(handle, inode, NULL, ablocks[i], 1,
1233                                          EXT4_FREE_BLOCKS_METADATA);
1234                 }
1235         }
1236         kfree(ablocks);
1237
1238         return err;
1239 }
1240
1241 /*
1242  * ext4_ext_grow_indepth:
1243  * implements tree growing procedure:
1244  * - allocates new block
1245  * - moves top-level data (index block or leaf) into the new block
1246  * - initializes new top-level, creating index that points to the
1247  *   just created block
1248  */
1249 static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
1250                                  unsigned int flags)
1251 {
1252         struct ext4_extent_header *neh;
1253         struct buffer_head *bh;
1254         ext4_fsblk_t newblock, goal = 0;
1255         struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
1256         int err = 0;
1257         size_t ext_size = 0;
1258
1259         /* Try to prepend new index to old one */
1260         if (ext_depth(inode))
1261                 goal = ext4_idx_pblock(EXT_FIRST_INDEX(ext_inode_hdr(inode)));
1262         if (goal > le32_to_cpu(es->s_first_data_block)) {
1263                 flags |= EXT4_MB_HINT_TRY_GOAL;
1264                 goal--;
1265         } else
1266                 goal = ext4_inode_to_goal_block(inode);
1267         newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
1268                                         NULL, &err);
1269         if (newblock == 0)
1270                 return err;
1271
1272         bh = sb_getblk_gfp(inode->i_sb, newblock, __GFP_MOVABLE | GFP_NOFS);
1273         if (unlikely(!bh))
1274                 return -ENOMEM;
1275         lock_buffer(bh);
1276
1277         err = ext4_journal_get_create_access(handle, bh);
1278         if (err) {
1279                 unlock_buffer(bh);
1280                 goto out;
1281         }
1282
1283         ext_size = sizeof(EXT4_I(inode)->i_data);
1284         /* move top-level index/leaf into new block */
1285         memmove(bh->b_data, EXT4_I(inode)->i_data, ext_size);
1286         /* zero out unused area in the extent block */
1287         memset(bh->b_data + ext_size, 0, inode->i_sb->s_blocksize - ext_size);
1288
1289         /* set size of new block */
1290         neh = ext_block_hdr(bh);
1291         /* old root could have indexes or leaves
1292          * so calculate e_max right way */
1293         if (ext_depth(inode))
1294                 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1295         else
1296                 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1297         neh->eh_magic = EXT4_EXT_MAGIC;
1298         ext4_extent_block_csum_set(inode, neh);
1299         set_buffer_uptodate(bh);
1300         unlock_buffer(bh);
1301
1302         err = ext4_handle_dirty_metadata(handle, inode, bh);
1303         if (err)
1304                 goto out;
1305
1306         /* Update top-level index: num,max,pointer */
1307         neh = ext_inode_hdr(inode);
1308         neh->eh_entries = cpu_to_le16(1);
1309         ext4_idx_store_pblock(EXT_FIRST_INDEX(neh), newblock);
1310         if (neh->eh_depth == 0) {
1311                 /* Root extent block becomes index block */
1312                 neh->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode, 0));
1313                 EXT_FIRST_INDEX(neh)->ei_block =
1314                         EXT_FIRST_EXTENT(neh)->ee_block;
1315         }
1316         ext_debug("new root: num %d(%d), lblock %d, ptr %llu\n",
1317                   le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max),
1318                   le32_to_cpu(EXT_FIRST_INDEX(neh)->ei_block),
1319                   ext4_idx_pblock(EXT_FIRST_INDEX(neh)));
1320
1321         le16_add_cpu(&neh->eh_depth, 1);
1322         ext4_mark_inode_dirty(handle, inode);
1323 out:
1324         brelse(bh);
1325
1326         return err;
1327 }
1328
1329 /*
1330  * ext4_ext_create_new_leaf:
1331  * finds empty index and adds new leaf.
1332  * if no free index is found, then it requests in-depth growing.
1333  */
1334 static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
1335                                     unsigned int mb_flags,
1336                                     unsigned int gb_flags,
1337                                     struct ext4_ext_path **ppath,
1338                                     struct ext4_extent *newext)
1339 {
1340         struct ext4_ext_path *path = *ppath;
1341         struct ext4_ext_path *curp;
1342         int depth, i, err = 0;
1343
1344 repeat:
1345         i = depth = ext_depth(inode);
1346
1347         /* walk up to the tree and look for free index entry */
1348         curp = path + depth;
1349         while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) {
1350                 i--;
1351                 curp--;
1352         }
1353
1354         /* we use already allocated block for index block,
1355          * so subsequent data blocks should be contiguous */
1356         if (EXT_HAS_FREE_INDEX(curp)) {
1357                 /* if we found index with free entry, then use that
1358                  * entry: create all needed subtree and add new leaf */
1359                 err = ext4_ext_split(handle, inode, mb_flags, path, newext, i);
1360                 if (err)
1361                         goto out;
1362
1363                 /* refill path */
1364                 path = ext4_find_extent(inode,
1365                                     (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1366                                     ppath, gb_flags);
1367                 if (IS_ERR(path))
1368                         err = PTR_ERR(path);
1369         } else {
1370                 /* tree is full, time to grow in depth */
1371                 err = ext4_ext_grow_indepth(handle, inode, mb_flags);
1372                 if (err)
1373                         goto out;
1374
1375                 /* refill path */
1376                 path = ext4_find_extent(inode,
1377                                    (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1378                                     ppath, gb_flags);
1379                 if (IS_ERR(path)) {
1380                         err = PTR_ERR(path);
1381                         goto out;
1382                 }
1383
1384                 /*
1385                  * only first (depth 0 -> 1) produces free space;
1386                  * in all other cases we have to split the grown tree
1387                  */
1388                 depth = ext_depth(inode);
1389                 if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) {
1390                         /* now we need to split */
1391                         goto repeat;
1392                 }
1393         }
1394
1395 out:
1396         return err;
1397 }
1398
1399 /*
1400  * search the closest allocated block to the left for *logical
1401  * and returns it at @logical + it's physical address at @phys
1402  * if *logical is the smallest allocated block, the function
1403  * returns 0 at @phys
1404  * return value contains 0 (success) or error code
1405  */
1406 static int ext4_ext_search_left(struct inode *inode,
1407                                 struct ext4_ext_path *path,
1408                                 ext4_lblk_t *logical, ext4_fsblk_t *phys)
1409 {
1410         struct ext4_extent_idx *ix;
1411         struct ext4_extent *ex;
1412         int depth, ee_len;
1413
1414         if (unlikely(path == NULL)) {
1415                 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1416                 return -EFSCORRUPTED;
1417         }
1418         depth = path->p_depth;
1419         *phys = 0;
1420
1421         if (depth == 0 && path->p_ext == NULL)
1422                 return 0;
1423
1424         /* usually extent in the path covers blocks smaller
1425          * then *logical, but it can be that extent is the
1426          * first one in the file */
1427
1428         ex = path[depth].p_ext;
1429         ee_len = ext4_ext_get_actual_len(ex);
1430         if (*logical < le32_to_cpu(ex->ee_block)) {
1431                 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1432                         EXT4_ERROR_INODE(inode,
1433                                          "EXT_FIRST_EXTENT != ex *logical %d ee_block %d!",
1434                                          *logical, le32_to_cpu(ex->ee_block));
1435                         return -EFSCORRUPTED;
1436                 }
1437                 while (--depth >= 0) {
1438                         ix = path[depth].p_idx;
1439                         if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1440                                 EXT4_ERROR_INODE(inode,
1441                                   "ix (%d) != EXT_FIRST_INDEX (%d) (depth %d)!",
1442                                   ix != NULL ? le32_to_cpu(ix->ei_block) : 0,
1443                                   EXT_FIRST_INDEX(path[depth].p_hdr) != NULL ?
1444                 le32_to_cpu(EXT_FIRST_INDEX(path[depth].p_hdr)->ei_block) : 0,
1445                                   depth);
1446                                 return -EFSCORRUPTED;
1447                         }
1448                 }
1449                 return 0;
1450         }
1451
1452         if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1453                 EXT4_ERROR_INODE(inode,
1454                                  "logical %d < ee_block %d + ee_len %d!",
1455                                  *logical, le32_to_cpu(ex->ee_block), ee_len);
1456                 return -EFSCORRUPTED;
1457         }
1458
1459         *logical = le32_to_cpu(ex->ee_block) + ee_len - 1;
1460         *phys = ext4_ext_pblock(ex) + ee_len - 1;
1461         return 0;
1462 }
1463
1464 /*
1465  * search the closest allocated block to the right for *logical
1466  * and returns it at @logical + it's physical address at @phys
1467  * if *logical is the largest allocated block, the function
1468  * returns 0 at @phys
1469  * return value contains 0 (success) or error code
1470  */
1471 static int ext4_ext_search_right(struct inode *inode,
1472                                  struct ext4_ext_path *path,
1473                                  ext4_lblk_t *logical, ext4_fsblk_t *phys,
1474                                  struct ext4_extent **ret_ex)
1475 {
1476         struct buffer_head *bh = NULL;
1477         struct ext4_extent_header *eh;
1478         struct ext4_extent_idx *ix;
1479         struct ext4_extent *ex;
1480         ext4_fsblk_t block;
1481         int depth;      /* Note, NOT eh_depth; depth from top of tree */
1482         int ee_len;
1483
1484         if (unlikely(path == NULL)) {
1485                 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1486                 return -EFSCORRUPTED;
1487         }
1488         depth = path->p_depth;
1489         *phys = 0;
1490
1491         if (depth == 0 && path->p_ext == NULL)
1492                 return 0;
1493
1494         /* usually extent in the path covers blocks smaller
1495          * then *logical, but it can be that extent is the
1496          * first one in the file */
1497
1498         ex = path[depth].p_ext;
1499         ee_len = ext4_ext_get_actual_len(ex);
1500         if (*logical < le32_to_cpu(ex->ee_block)) {
1501                 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1502                         EXT4_ERROR_INODE(inode,
1503                                          "first_extent(path[%d].p_hdr) != ex",
1504                                          depth);
1505                         return -EFSCORRUPTED;
1506                 }
1507                 while (--depth >= 0) {
1508                         ix = path[depth].p_idx;
1509                         if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1510                                 EXT4_ERROR_INODE(inode,
1511                                                  "ix != EXT_FIRST_INDEX *logical %d!",
1512                                                  *logical);
1513                                 return -EFSCORRUPTED;
1514                         }
1515                 }
1516                 goto found_extent;
1517         }
1518
1519         if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1520                 EXT4_ERROR_INODE(inode,
1521                                  "logical %d < ee_block %d + ee_len %d!",
1522                                  *logical, le32_to_cpu(ex->ee_block), ee_len);
1523                 return -EFSCORRUPTED;
1524         }
1525
1526         if (ex != EXT_LAST_EXTENT(path[depth].p_hdr)) {
1527                 /* next allocated block in this leaf */
1528                 ex++;
1529                 goto found_extent;
1530         }
1531
1532         /* go up and search for index to the right */
1533         while (--depth >= 0) {
1534                 ix = path[depth].p_idx;
1535                 if (ix != EXT_LAST_INDEX(path[depth].p_hdr))
1536                         goto got_index;
1537         }
1538
1539         /* we've gone up to the root and found no index to the right */
1540         return 0;
1541
1542 got_index:
1543         /* we've found index to the right, let's
1544          * follow it and find the closest allocated
1545          * block to the right */
1546         ix++;
1547         block = ext4_idx_pblock(ix);
1548         while (++depth < path->p_depth) {
1549                 /* subtract from p_depth to get proper eh_depth */
1550                 bh = read_extent_tree_block(inode, block,
1551                                             path->p_depth - depth, 0);
1552                 if (IS_ERR(bh))
1553                         return PTR_ERR(bh);
1554                 eh = ext_block_hdr(bh);
1555                 ix = EXT_FIRST_INDEX(eh);
1556                 block = ext4_idx_pblock(ix);
1557                 put_bh(bh);
1558         }
1559
1560         bh = read_extent_tree_block(inode, block, path->p_depth - depth, 0);
1561         if (IS_ERR(bh))
1562                 return PTR_ERR(bh);
1563         eh = ext_block_hdr(bh);
1564         ex = EXT_FIRST_EXTENT(eh);
1565 found_extent:
1566         *logical = le32_to_cpu(ex->ee_block);
1567         *phys = ext4_ext_pblock(ex);
1568         *ret_ex = ex;
1569         if (bh)
1570                 put_bh(bh);
1571         return 0;
1572 }
1573
1574 /*
1575  * ext4_ext_next_allocated_block:
1576  * returns allocated block in subsequent extent or EXT_MAX_BLOCKS.
1577  * NOTE: it considers block number from index entry as
1578  * allocated block. Thus, index entries have to be consistent
1579  * with leaves.
1580  */
1581 ext4_lblk_t
1582 ext4_ext_next_allocated_block(struct ext4_ext_path *path)
1583 {
1584         int depth;
1585
1586         BUG_ON(path == NULL);
1587         depth = path->p_depth;
1588
1589         if (depth == 0 && path->p_ext == NULL)
1590                 return EXT_MAX_BLOCKS;
1591
1592         while (depth >= 0) {
1593                 if (depth == path->p_depth) {
1594                         /* leaf */
1595                         if (path[depth].p_ext &&
1596                                 path[depth].p_ext !=
1597                                         EXT_LAST_EXTENT(path[depth].p_hdr))
1598                           return le32_to_cpu(path[depth].p_ext[1].ee_block);
1599                 } else {
1600                         /* index */
1601                         if (path[depth].p_idx !=
1602                                         EXT_LAST_INDEX(path[depth].p_hdr))
1603                           return le32_to_cpu(path[depth].p_idx[1].ei_block);
1604                 }
1605                 depth--;
1606         }
1607
1608         return EXT_MAX_BLOCKS;
1609 }
1610
1611 /*
1612  * ext4_ext_next_leaf_block:
1613  * returns first allocated block from next leaf or EXT_MAX_BLOCKS
1614  */
1615 static ext4_lblk_t ext4_ext_next_leaf_block(struct ext4_ext_path *path)
1616 {
1617         int depth;
1618
1619         BUG_ON(path == NULL);
1620         depth = path->p_depth;
1621
1622         /* zero-tree has no leaf blocks at all */
1623         if (depth == 0)
1624                 return EXT_MAX_BLOCKS;
1625
1626         /* go to index block */
1627         depth--;
1628
1629         while (depth >= 0) {
1630                 if (path[depth].p_idx !=
1631                                 EXT_LAST_INDEX(path[depth].p_hdr))
1632                         return (ext4_lblk_t)
1633                                 le32_to_cpu(path[depth].p_idx[1].ei_block);
1634                 depth--;
1635         }
1636
1637         return EXT_MAX_BLOCKS;
1638 }
1639
1640 /*
1641  * ext4_ext_correct_indexes:
1642  * if leaf gets modified and modified extent is first in the leaf,
1643  * then we have to correct all indexes above.
1644  * TODO: do we need to correct tree in all cases?
1645  */
1646 static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode,
1647                                 struct ext4_ext_path *path)
1648 {
1649         struct ext4_extent_header *eh;
1650         int depth = ext_depth(inode);
1651         struct ext4_extent *ex;
1652         __le32 border;
1653         int k, err = 0;
1654
1655         eh = path[depth].p_hdr;
1656         ex = path[depth].p_ext;
1657
1658         if (unlikely(ex == NULL || eh == NULL)) {
1659                 EXT4_ERROR_INODE(inode,
1660                                  "ex %p == NULL or eh %p == NULL", ex, eh);
1661                 return -EFSCORRUPTED;
1662         }
1663
1664         if (depth == 0) {
1665                 /* there is no tree at all */
1666                 return 0;
1667         }
1668
1669         if (ex != EXT_FIRST_EXTENT(eh)) {
1670                 /* we correct tree if first leaf got modified only */
1671                 return 0;
1672         }
1673
1674         /*
1675          * TODO: we need correction if border is smaller than current one
1676          */
1677         k = depth - 1;
1678         border = path[depth].p_ext->ee_block;
1679         err = ext4_ext_get_access(handle, inode, path + k);
1680         if (err)
1681                 return err;
1682         path[k].p_idx->ei_block = border;
1683         err = ext4_ext_dirty(handle, inode, path + k);
1684         if (err)
1685                 return err;
1686
1687         while (k--) {
1688                 /* change all left-side indexes */
1689                 if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr))
1690                         break;
1691                 err = ext4_ext_get_access(handle, inode, path + k);
1692                 if (err)
1693                         break;
1694                 path[k].p_idx->ei_block = border;
1695                 err = ext4_ext_dirty(handle, inode, path + k);
1696                 if (err)
1697                         break;
1698         }
1699
1700         return err;
1701 }
1702
1703 static int ext4_can_extents_be_merged(struct inode *inode,
1704                                       struct ext4_extent *ex1,
1705                                       struct ext4_extent *ex2)
1706 {
1707         unsigned short ext1_ee_len, ext2_ee_len;
1708
1709         if (ext4_ext_is_unwritten(ex1) != ext4_ext_is_unwritten(ex2))
1710                 return 0;
1711
1712         ext1_ee_len = ext4_ext_get_actual_len(ex1);
1713         ext2_ee_len = ext4_ext_get_actual_len(ex2);
1714
1715         if (le32_to_cpu(ex1->ee_block) + ext1_ee_len !=
1716                         le32_to_cpu(ex2->ee_block))
1717                 return 0;
1718
1719         /*
1720          * To allow future support for preallocated extents to be added
1721          * as an RO_COMPAT feature, refuse to merge to extents if
1722          * this can result in the top bit of ee_len being set.
1723          */
1724         if (ext1_ee_len + ext2_ee_len > EXT_INIT_MAX_LEN)
1725                 return 0;
1726
1727         if (ext4_ext_is_unwritten(ex1) &&
1728             ext1_ee_len + ext2_ee_len > EXT_UNWRITTEN_MAX_LEN)
1729                 return 0;
1730 #ifdef AGGRESSIVE_TEST
1731         if (ext1_ee_len >= 4)
1732                 return 0;
1733 #endif
1734
1735         if (ext4_ext_pblock(ex1) + ext1_ee_len == ext4_ext_pblock(ex2))
1736                 return 1;
1737         return 0;
1738 }
1739
1740 /*
1741  * This function tries to merge the "ex" extent to the next extent in the tree.
1742  * It always tries to merge towards right. If you want to merge towards
1743  * left, pass "ex - 1" as argument instead of "ex".
1744  * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns
1745  * 1 if they got merged.
1746  */
1747 static int ext4_ext_try_to_merge_right(struct inode *inode,
1748                                  struct ext4_ext_path *path,
1749                                  struct ext4_extent *ex)
1750 {
1751         struct ext4_extent_header *eh;
1752         unsigned int depth, len;
1753         int merge_done = 0, unwritten;
1754
1755         depth = ext_depth(inode);
1756         BUG_ON(path[depth].p_hdr == NULL);
1757         eh = path[depth].p_hdr;
1758
1759         while (ex < EXT_LAST_EXTENT(eh)) {
1760                 if (!ext4_can_extents_be_merged(inode, ex, ex + 1))
1761                         break;
1762                 /* merge with next extent! */
1763                 unwritten = ext4_ext_is_unwritten(ex);
1764                 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1765                                 + ext4_ext_get_actual_len(ex + 1));
1766                 if (unwritten)
1767                         ext4_ext_mark_unwritten(ex);
1768
1769                 if (ex + 1 < EXT_LAST_EXTENT(eh)) {
1770                         len = (EXT_LAST_EXTENT(eh) - ex - 1)
1771                                 * sizeof(struct ext4_extent);
1772                         memmove(ex + 1, ex + 2, len);
1773                 }
1774                 le16_add_cpu(&eh->eh_entries, -1);
1775                 merge_done = 1;
1776                 WARN_ON(eh->eh_entries == 0);
1777                 if (!eh->eh_entries)
1778                         EXT4_ERROR_INODE(inode, "eh->eh_entries = 0!");
1779         }
1780
1781         return merge_done;
1782 }
1783
1784 /*
1785  * This function does a very simple check to see if we can collapse
1786  * an extent tree with a single extent tree leaf block into the inode.
1787  */
1788 static void ext4_ext_try_to_merge_up(handle_t *handle,
1789                                      struct inode *inode,
1790                                      struct ext4_ext_path *path)
1791 {
1792         size_t s;
1793         unsigned max_root = ext4_ext_space_root(inode, 0);
1794         ext4_fsblk_t blk;
1795
1796         if ((path[0].p_depth != 1) ||
1797             (le16_to_cpu(path[0].p_hdr->eh_entries) != 1) ||
1798             (le16_to_cpu(path[1].p_hdr->eh_entries) > max_root))
1799                 return;
1800
1801         /*
1802          * We need to modify the block allocation bitmap and the block
1803          * group descriptor to release the extent tree block.  If we
1804          * can't get the journal credits, give up.
1805          */
1806         if (ext4_journal_extend(handle, 2,
1807                         ext4_free_metadata_revoke_credits(inode->i_sb, 1)))
1808                 return;
1809
1810         /*
1811          * Copy the extent data up to the inode
1812          */
1813         blk = ext4_idx_pblock(path[0].p_idx);
1814         s = le16_to_cpu(path[1].p_hdr->eh_entries) *
1815                 sizeof(struct ext4_extent_idx);
1816         s += sizeof(struct ext4_extent_header);
1817
1818         path[1].p_maxdepth = path[0].p_maxdepth;
1819         memcpy(path[0].p_hdr, path[1].p_hdr, s);
1820         path[0].p_depth = 0;
1821         path[0].p_ext = EXT_FIRST_EXTENT(path[0].p_hdr) +
1822                 (path[1].p_ext - EXT_FIRST_EXTENT(path[1].p_hdr));
1823         path[0].p_hdr->eh_max = cpu_to_le16(max_root);
1824
1825         brelse(path[1].p_bh);
1826         ext4_free_blocks(handle, inode, NULL, blk, 1,
1827                          EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
1828 }
1829
1830 /*
1831  * This function tries to merge the @ex extent to neighbours in the tree.
1832  * return 1 if merge left else 0.
1833  */
1834 static void ext4_ext_try_to_merge(handle_t *handle,
1835                                   struct inode *inode,
1836                                   struct ext4_ext_path *path,
1837                                   struct ext4_extent *ex) {
1838         struct ext4_extent_header *eh;
1839         unsigned int depth;
1840         int merge_done = 0;
1841
1842         depth = ext_depth(inode);
1843         BUG_ON(path[depth].p_hdr == NULL);
1844         eh = path[depth].p_hdr;
1845
1846         if (ex > EXT_FIRST_EXTENT(eh))
1847                 merge_done = ext4_ext_try_to_merge_right(inode, path, ex - 1);
1848
1849         if (!merge_done)
1850                 (void) ext4_ext_try_to_merge_right(inode, path, ex);
1851
1852         ext4_ext_try_to_merge_up(handle, inode, path);
1853 }
1854
1855 /*
1856  * check if a portion of the "newext" extent overlaps with an
1857  * existing extent.
1858  *
1859  * If there is an overlap discovered, it updates the length of the newext
1860  * such that there will be no overlap, and then returns 1.
1861  * If there is no overlap found, it returns 0.
1862  */
1863 static unsigned int ext4_ext_check_overlap(struct ext4_sb_info *sbi,
1864                                            struct inode *inode,
1865                                            struct ext4_extent *newext,
1866                                            struct ext4_ext_path *path)
1867 {
1868         ext4_lblk_t b1, b2;
1869         unsigned int depth, len1;
1870         unsigned int ret = 0;
1871
1872         b1 = le32_to_cpu(newext->ee_block);
1873         len1 = ext4_ext_get_actual_len(newext);
1874         depth = ext_depth(inode);
1875         if (!path[depth].p_ext)
1876                 goto out;
1877         b2 = EXT4_LBLK_CMASK(sbi, le32_to_cpu(path[depth].p_ext->ee_block));
1878
1879         /*
1880          * get the next allocated block if the extent in the path
1881          * is before the requested block(s)
1882          */
1883         if (b2 < b1) {
1884                 b2 = ext4_ext_next_allocated_block(path);
1885                 if (b2 == EXT_MAX_BLOCKS)
1886                         goto out;
1887                 b2 = EXT4_LBLK_CMASK(sbi, b2);
1888         }
1889
1890         /* check for wrap through zero on extent logical start block*/
1891         if (b1 + len1 < b1) {
1892                 len1 = EXT_MAX_BLOCKS - b1;
1893                 newext->ee_len = cpu_to_le16(len1);
1894                 ret = 1;
1895         }
1896
1897         /* check for overlap */
1898         if (b1 + len1 > b2) {
1899                 newext->ee_len = cpu_to_le16(b2 - b1);
1900                 ret = 1;
1901         }
1902 out:
1903         return ret;
1904 }
1905
1906 /*
1907  * ext4_ext_insert_extent:
1908  * tries to merge requsted extent into the existing extent or
1909  * inserts requested extent as new one into the tree,
1910  * creating new leaf in the no-space case.
1911  */
1912 int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
1913                                 struct ext4_ext_path **ppath,
1914                                 struct ext4_extent *newext, int gb_flags)
1915 {
1916         struct ext4_ext_path *path = *ppath;
1917         struct ext4_extent_header *eh;
1918         struct ext4_extent *ex, *fex;
1919         struct ext4_extent *nearex; /* nearest extent */
1920         struct ext4_ext_path *npath = NULL;
1921         int depth, len, err;
1922         ext4_lblk_t next;
1923         int mb_flags = 0, unwritten;
1924
1925         if (gb_flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
1926                 mb_flags |= EXT4_MB_DELALLOC_RESERVED;
1927         if (unlikely(ext4_ext_get_actual_len(newext) == 0)) {
1928                 EXT4_ERROR_INODE(inode, "ext4_ext_get_actual_len(newext) == 0");
1929                 return -EFSCORRUPTED;
1930         }
1931         depth = ext_depth(inode);
1932         ex = path[depth].p_ext;
1933         eh = path[depth].p_hdr;
1934         if (unlikely(path[depth].p_hdr == NULL)) {
1935                 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
1936                 return -EFSCORRUPTED;
1937         }
1938
1939         /* try to insert block into found extent and return */
1940         if (ex && !(gb_flags & EXT4_GET_BLOCKS_PRE_IO)) {
1941
1942                 /*
1943                  * Try to see whether we should rather test the extent on
1944                  * right from ex, or from the left of ex. This is because
1945                  * ext4_find_extent() can return either extent on the
1946                  * left, or on the right from the searched position. This
1947                  * will make merging more effective.
1948                  */
1949                 if (ex < EXT_LAST_EXTENT(eh) &&
1950                     (le32_to_cpu(ex->ee_block) +
1951                     ext4_ext_get_actual_len(ex) <
1952                     le32_to_cpu(newext->ee_block))) {
1953                         ex += 1;
1954                         goto prepend;
1955                 } else if ((ex > EXT_FIRST_EXTENT(eh)) &&
1956                            (le32_to_cpu(newext->ee_block) +
1957                            ext4_ext_get_actual_len(newext) <
1958                            le32_to_cpu(ex->ee_block)))
1959                         ex -= 1;
1960
1961                 /* Try to append newex to the ex */
1962                 if (ext4_can_extents_be_merged(inode, ex, newext)) {
1963                         ext_debug("append [%d]%d block to %u:[%d]%d"
1964                                   "(from %llu)\n",
1965                                   ext4_ext_is_unwritten(newext),
1966                                   ext4_ext_get_actual_len(newext),
1967                                   le32_to_cpu(ex->ee_block),
1968                                   ext4_ext_is_unwritten(ex),
1969                                   ext4_ext_get_actual_len(ex),
1970                                   ext4_ext_pblock(ex));
1971                         err = ext4_ext_get_access(handle, inode,
1972                                                   path + depth);
1973                         if (err)
1974                                 return err;
1975                         unwritten = ext4_ext_is_unwritten(ex);
1976                         ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1977                                         + ext4_ext_get_actual_len(newext));
1978                         if (unwritten)
1979                                 ext4_ext_mark_unwritten(ex);
1980                         eh = path[depth].p_hdr;
1981                         nearex = ex;
1982                         goto merge;
1983                 }
1984
1985 prepend:
1986                 /* Try to prepend newex to the ex */
1987                 if (ext4_can_extents_be_merged(inode, newext, ex)) {
1988                         ext_debug("prepend %u[%d]%d block to %u:[%d]%d"
1989                                   "(from %llu)\n",
1990                                   le32_to_cpu(newext->ee_block),
1991                                   ext4_ext_is_unwritten(newext),
1992                                   ext4_ext_get_actual_len(newext),
1993                                   le32_to_cpu(ex->ee_block),
1994                                   ext4_ext_is_unwritten(ex),
1995                                   ext4_ext_get_actual_len(ex),
1996                                   ext4_ext_pblock(ex));
1997                         err = ext4_ext_get_access(handle, inode,
1998                                                   path + depth);
1999                         if (err)
2000                                 return err;
2001
2002                         unwritten = ext4_ext_is_unwritten(ex);
2003                         ex->ee_block = newext->ee_block;
2004                         ext4_ext_store_pblock(ex, ext4_ext_pblock(newext));
2005                         ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
2006                                         + ext4_ext_get_actual_len(newext));
2007                         if (unwritten)
2008                                 ext4_ext_mark_unwritten(ex);
2009                         eh = path[depth].p_hdr;
2010                         nearex = ex;
2011                         goto merge;
2012                 }
2013         }
2014
2015         depth = ext_depth(inode);
2016         eh = path[depth].p_hdr;
2017         if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max))
2018                 goto has_space;
2019
2020         /* probably next leaf has space for us? */
2021         fex = EXT_LAST_EXTENT(eh);
2022         next = EXT_MAX_BLOCKS;
2023         if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block))
2024                 next = ext4_ext_next_leaf_block(path);
2025         if (next != EXT_MAX_BLOCKS) {
2026                 ext_debug("next leaf block - %u\n", next);
2027                 BUG_ON(npath != NULL);
2028                 npath = ext4_find_extent(inode, next, NULL, 0);
2029                 if (IS_ERR(npath))
2030                         return PTR_ERR(npath);
2031                 BUG_ON(npath->p_depth != path->p_depth);
2032                 eh = npath[depth].p_hdr;
2033                 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) {
2034                         ext_debug("next leaf isn't full(%d)\n",
2035                                   le16_to_cpu(eh->eh_entries));
2036                         path = npath;
2037                         goto has_space;
2038                 }
2039                 ext_debug("next leaf has no free space(%d,%d)\n",
2040                           le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
2041         }
2042
2043         /*
2044          * There is no free space in the found leaf.
2045          * We're gonna add a new leaf in the tree.
2046          */
2047         if (gb_flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
2048                 mb_flags |= EXT4_MB_USE_RESERVED;
2049         err = ext4_ext_create_new_leaf(handle, inode, mb_flags, gb_flags,
2050                                        ppath, newext);
2051         if (err)
2052                 goto cleanup;
2053         depth = ext_depth(inode);
2054         eh = path[depth].p_hdr;
2055
2056 has_space:
2057         nearex = path[depth].p_ext;
2058
2059         err = ext4_ext_get_access(handle, inode, path + depth);
2060         if (err)
2061                 goto cleanup;
2062
2063         if (!nearex) {
2064                 /* there is no extent in this leaf, create first one */
2065                 ext_debug("first extent in the leaf: %u:%llu:[%d]%d\n",
2066                                 le32_to_cpu(newext->ee_block),
2067                                 ext4_ext_pblock(newext),
2068                                 ext4_ext_is_unwritten(newext),
2069                                 ext4_ext_get_actual_len(newext));
2070                 nearex = EXT_FIRST_EXTENT(eh);
2071         } else {
2072                 if (le32_to_cpu(newext->ee_block)
2073                            > le32_to_cpu(nearex->ee_block)) {
2074                         /* Insert after */
2075                         ext_debug("insert %u:%llu:[%d]%d before: "
2076                                         "nearest %p\n",
2077                                         le32_to_cpu(newext->ee_block),
2078                                         ext4_ext_pblock(newext),
2079                                         ext4_ext_is_unwritten(newext),
2080                                         ext4_ext_get_actual_len(newext),
2081                                         nearex);
2082                         nearex++;
2083                 } else {
2084                         /* Insert before */
2085                         BUG_ON(newext->ee_block == nearex->ee_block);
2086                         ext_debug("insert %u:%llu:[%d]%d after: "
2087                                         "nearest %p\n",
2088                                         le32_to_cpu(newext->ee_block),
2089                                         ext4_ext_pblock(newext),
2090                                         ext4_ext_is_unwritten(newext),
2091                                         ext4_ext_get_actual_len(newext),
2092                                         nearex);
2093                 }
2094                 len = EXT_LAST_EXTENT(eh) - nearex + 1;
2095                 if (len > 0) {
2096                         ext_debug("insert %u:%llu:[%d]%d: "
2097                                         "move %d extents from 0x%p to 0x%p\n",
2098                                         le32_to_cpu(newext->ee_block),
2099                                         ext4_ext_pblock(newext),
2100                                         ext4_ext_is_unwritten(newext),
2101                                         ext4_ext_get_actual_len(newext),
2102                                         len, nearex, nearex + 1);
2103                         memmove(nearex + 1, nearex,
2104                                 len * sizeof(struct ext4_extent));
2105                 }
2106         }
2107
2108         le16_add_cpu(&eh->eh_entries, 1);
2109         path[depth].p_ext = nearex;
2110         nearex->ee_block = newext->ee_block;
2111         ext4_ext_store_pblock(nearex, ext4_ext_pblock(newext));
2112         nearex->ee_len = newext->ee_len;
2113
2114 merge:
2115         /* try to merge extents */
2116         if (!(gb_flags & EXT4_GET_BLOCKS_PRE_IO))
2117                 ext4_ext_try_to_merge(handle, inode, path, nearex);
2118
2119
2120         /* time to correct all indexes above */
2121         err = ext4_ext_correct_indexes(handle, inode, path);
2122         if (err)
2123                 goto cleanup;
2124
2125         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
2126
2127 cleanup:
2128         ext4_ext_drop_refs(npath);
2129         kfree(npath);
2130         return err;
2131 }
2132
2133 static int ext4_fill_fiemap_extents(struct inode *inode,
2134                                     ext4_lblk_t block, ext4_lblk_t num,
2135                                     struct fiemap_extent_info *fieinfo)
2136 {
2137         struct ext4_ext_path *path = NULL;
2138         struct ext4_extent *ex;
2139         struct extent_status es;
2140         ext4_lblk_t next, next_del, start = 0, end = 0;
2141         ext4_lblk_t last = block + num;
2142         int exists, depth = 0, err = 0;
2143         unsigned int flags = 0;
2144         unsigned char blksize_bits = inode->i_sb->s_blocksize_bits;
2145
2146         while (block < last && block != EXT_MAX_BLOCKS) {
2147                 num = last - block;
2148                 /* find extent for this block */
2149                 down_read(&EXT4_I(inode)->i_data_sem);
2150
2151                 path = ext4_find_extent(inode, block, &path, 0);
2152                 if (IS_ERR(path)) {
2153                         up_read(&EXT4_I(inode)->i_data_sem);
2154                         err = PTR_ERR(path);
2155                         path = NULL;
2156                         break;
2157                 }
2158
2159                 depth = ext_depth(inode);
2160                 if (unlikely(path[depth].p_hdr == NULL)) {
2161                         up_read(&EXT4_I(inode)->i_data_sem);
2162                         EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2163                         err = -EFSCORRUPTED;
2164                         break;
2165                 }
2166                 ex = path[depth].p_ext;
2167                 next = ext4_ext_next_allocated_block(path);
2168
2169                 flags = 0;
2170                 exists = 0;
2171                 if (!ex) {
2172                         /* there is no extent yet, so try to allocate
2173                          * all requested space */
2174                         start = block;
2175                         end = block + num;
2176                 } else if (le32_to_cpu(ex->ee_block) > block) {
2177                         /* need to allocate space before found extent */
2178                         start = block;
2179                         end = le32_to_cpu(ex->ee_block);
2180                         if (block + num < end)
2181                                 end = block + num;
2182                 } else if (block >= le32_to_cpu(ex->ee_block)
2183                                         + ext4_ext_get_actual_len(ex)) {
2184                         /* need to allocate space after found extent */
2185                         start = block;
2186                         end = block + num;
2187                         if (end >= next)
2188                                 end = next;
2189                 } else if (block >= le32_to_cpu(ex->ee_block)) {
2190                         /*
2191                          * some part of requested space is covered
2192                          * by found extent
2193                          */
2194                         start = block;
2195                         end = le32_to_cpu(ex->ee_block)
2196                                 + ext4_ext_get_actual_len(ex);
2197                         if (block + num < end)
2198                                 end = block + num;
2199                         exists = 1;
2200                 } else {
2201                         BUG();
2202                 }
2203                 BUG_ON(end <= start);
2204
2205                 if (!exists) {
2206                         es.es_lblk = start;
2207                         es.es_len = end - start;
2208                         es.es_pblk = 0;
2209                 } else {
2210                         es.es_lblk = le32_to_cpu(ex->ee_block);
2211                         es.es_len = ext4_ext_get_actual_len(ex);
2212                         es.es_pblk = ext4_ext_pblock(ex);
2213                         if (ext4_ext_is_unwritten(ex))
2214                                 flags |= FIEMAP_EXTENT_UNWRITTEN;
2215                 }
2216
2217                 /*
2218                  * Find delayed extent and update es accordingly. We call
2219                  * it even in !exists case to find out whether es is the
2220                  * last existing extent or not.
2221                  */
2222                 next_del = ext4_find_delayed_extent(inode, &es);
2223                 if (!exists && next_del) {
2224                         exists = 1;
2225                         flags |= (FIEMAP_EXTENT_DELALLOC |
2226                                   FIEMAP_EXTENT_UNKNOWN);
2227                 }
2228                 up_read(&EXT4_I(inode)->i_data_sem);
2229
2230                 if (unlikely(es.es_len == 0)) {
2231                         EXT4_ERROR_INODE(inode, "es.es_len == 0");
2232                         err = -EFSCORRUPTED;
2233                         break;
2234                 }
2235
2236                 /*
2237                  * This is possible iff next == next_del == EXT_MAX_BLOCKS.
2238                  * we need to check next == EXT_MAX_BLOCKS because it is
2239                  * possible that an extent is with unwritten and delayed
2240                  * status due to when an extent is delayed allocated and
2241                  * is allocated by fallocate status tree will track both of
2242                  * them in a extent.
2243                  *
2244                  * So we could return a unwritten and delayed extent, and
2245                  * its block is equal to 'next'.
2246                  */
2247                 if (next == next_del && next == EXT_MAX_BLOCKS) {
2248                         flags |= FIEMAP_EXTENT_LAST;
2249                         if (unlikely(next_del != EXT_MAX_BLOCKS ||
2250                                      next != EXT_MAX_BLOCKS)) {
2251                                 EXT4_ERROR_INODE(inode,
2252                                                  "next extent == %u, next "
2253                                                  "delalloc extent = %u",
2254                                                  next, next_del);
2255                                 err = -EFSCORRUPTED;
2256                                 break;
2257                         }
2258                 }
2259
2260                 if (exists) {
2261                         err = fiemap_fill_next_extent(fieinfo,
2262                                 (__u64)es.es_lblk << blksize_bits,
2263                                 (__u64)es.es_pblk << blksize_bits,
2264                                 (__u64)es.es_len << blksize_bits,
2265                                 flags);
2266                         if (err < 0)
2267                                 break;
2268                         if (err == 1) {
2269                                 err = 0;
2270                                 break;
2271                         }
2272                 }
2273
2274                 block = es.es_lblk + es.es_len;
2275         }
2276
2277         ext4_ext_drop_refs(path);
2278         kfree(path);
2279         return err;
2280 }
2281
2282 static int ext4_fill_es_cache_info(struct inode *inode,
2283                                    ext4_lblk_t block, ext4_lblk_t num,
2284                                    struct fiemap_extent_info *fieinfo)
2285 {
2286         ext4_lblk_t next, end = block + num - 1;
2287         struct extent_status es;
2288         unsigned char blksize_bits = inode->i_sb->s_blocksize_bits;
2289         unsigned int flags;
2290         int err;
2291
2292         while (block <= end) {
2293                 next = 0;
2294                 flags = 0;
2295                 if (!ext4_es_lookup_extent(inode, block, &next, &es))
2296                         break;
2297                 if (ext4_es_is_unwritten(&es))
2298                         flags |= FIEMAP_EXTENT_UNWRITTEN;
2299                 if (ext4_es_is_delayed(&es))
2300                         flags |= (FIEMAP_EXTENT_DELALLOC |
2301                                   FIEMAP_EXTENT_UNKNOWN);
2302                 if (ext4_es_is_hole(&es))
2303                         flags |= EXT4_FIEMAP_EXTENT_HOLE;
2304                 if (next == 0)
2305                         flags |= FIEMAP_EXTENT_LAST;
2306                 if (flags & (FIEMAP_EXTENT_DELALLOC|
2307                              EXT4_FIEMAP_EXTENT_HOLE))
2308                         es.es_pblk = 0;
2309                 else
2310                         es.es_pblk = ext4_es_pblock(&es);
2311                 err = fiemap_fill_next_extent(fieinfo,
2312                                 (__u64)es.es_lblk << blksize_bits,
2313                                 (__u64)es.es_pblk << blksize_bits,
2314                                 (__u64)es.es_len << blksize_bits,
2315                                 flags);
2316                 if (next == 0)
2317                         break;
2318                 block = next;
2319                 if (err < 0)
2320                         return err;
2321                 if (err == 1)
2322                         return 0;
2323         }
2324         return 0;
2325 }
2326
2327
2328 /*
2329  * ext4_ext_determine_hole - determine hole around given block
2330  * @inode:      inode we lookup in
2331  * @path:       path in extent tree to @lblk
2332  * @lblk:       pointer to logical block around which we want to determine hole
2333  *
2334  * Determine hole length (and start if easily possible) around given logical
2335  * block. We don't try too hard to find the beginning of the hole but @path
2336  * actually points to extent before @lblk, we provide it.
2337  *
2338  * The function returns the length of a hole starting at @lblk. We update @lblk
2339  * to the beginning of the hole if we managed to find it.
2340  */
2341 static ext4_lblk_t ext4_ext_determine_hole(struct inode *inode,
2342                                            struct ext4_ext_path *path,
2343                                            ext4_lblk_t *lblk)
2344 {
2345         int depth = ext_depth(inode);
2346         struct ext4_extent *ex;
2347         ext4_lblk_t len;
2348
2349         ex = path[depth].p_ext;
2350         if (ex == NULL) {
2351                 /* there is no extent yet, so gap is [0;-] */
2352                 *lblk = 0;
2353                 len = EXT_MAX_BLOCKS;
2354         } else if (*lblk < le32_to_cpu(ex->ee_block)) {
2355                 len = le32_to_cpu(ex->ee_block) - *lblk;
2356         } else if (*lblk >= le32_to_cpu(ex->ee_block)
2357                         + ext4_ext_get_actual_len(ex)) {
2358                 ext4_lblk_t next;
2359
2360                 *lblk = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex);
2361                 next = ext4_ext_next_allocated_block(path);
2362                 BUG_ON(next == *lblk);
2363                 len = next - *lblk;
2364         } else {
2365                 BUG();
2366         }
2367         return len;
2368 }
2369
2370 /*
2371  * ext4_ext_put_gap_in_cache:
2372  * calculate boundaries of the gap that the requested block fits into
2373  * and cache this gap
2374  */
2375 static void
2376 ext4_ext_put_gap_in_cache(struct inode *inode, ext4_lblk_t hole_start,
2377                           ext4_lblk_t hole_len)
2378 {
2379         struct extent_status es;
2380
2381         ext4_es_find_extent_range(inode, &ext4_es_is_delayed, hole_start,
2382                                   hole_start + hole_len - 1, &es);
2383         if (es.es_len) {
2384                 /* There's delayed extent containing lblock? */
2385                 if (es.es_lblk <= hole_start)
2386                         return;
2387                 hole_len = min(es.es_lblk - hole_start, hole_len);
2388         }
2389         ext_debug(" -> %u:%u\n", hole_start, hole_len);
2390         ext4_es_insert_extent(inode, hole_start, hole_len, ~0,
2391                               EXTENT_STATUS_HOLE);
2392 }
2393
2394 /*
2395  * ext4_ext_rm_idx:
2396  * removes index from the index block.
2397  */
2398 static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
2399                         struct ext4_ext_path *path, int depth)
2400 {
2401         int err;
2402         ext4_fsblk_t leaf;
2403
2404         /* free index block */
2405         depth--;
2406         path = path + depth;
2407         leaf = ext4_idx_pblock(path->p_idx);
2408         if (unlikely(path->p_hdr->eh_entries == 0)) {
2409                 EXT4_ERROR_INODE(inode, "path->p_hdr->eh_entries == 0");
2410                 return -EFSCORRUPTED;
2411         }
2412         err = ext4_ext_get_access(handle, inode, path);
2413         if (err)
2414                 return err;
2415
2416         if (path->p_idx != EXT_LAST_INDEX(path->p_hdr)) {
2417                 int len = EXT_LAST_INDEX(path->p_hdr) - path->p_idx;
2418                 len *= sizeof(struct ext4_extent_idx);
2419                 memmove(path->p_idx, path->p_idx + 1, len);
2420         }
2421
2422         le16_add_cpu(&path->p_hdr->eh_entries, -1);
2423         err = ext4_ext_dirty(handle, inode, path);
2424         if (err)
2425                 return err;
2426         ext_debug("index is empty, remove it, free block %llu\n", leaf);
2427         trace_ext4_ext_rm_idx(inode, leaf);
2428
2429         ext4_free_blocks(handle, inode, NULL, leaf, 1,
2430                          EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
2431
2432         while (--depth >= 0) {
2433                 if (path->p_idx != EXT_FIRST_INDEX(path->p_hdr))
2434                         break;
2435                 path--;
2436                 err = ext4_ext_get_access(handle, inode, path);
2437                 if (err)
2438                         break;
2439                 path->p_idx->ei_block = (path+1)->p_idx->ei_block;
2440                 err = ext4_ext_dirty(handle, inode, path);
2441                 if (err)
2442                         break;
2443         }
2444         return err;
2445 }
2446
2447 /*
2448  * ext4_ext_calc_credits_for_single_extent:
2449  * This routine returns max. credits that needed to insert an extent
2450  * to the extent tree.
2451  * When pass the actual path, the caller should calculate credits
2452  * under i_data_sem.
2453  */
2454 int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks,
2455                                                 struct ext4_ext_path *path)
2456 {
2457         if (path) {
2458                 int depth = ext_depth(inode);
2459                 int ret = 0;
2460
2461                 /* probably there is space in leaf? */
2462                 if (le16_to_cpu(path[depth].p_hdr->eh_entries)
2463                                 < le16_to_cpu(path[depth].p_hdr->eh_max)) {
2464
2465                         /*
2466                          *  There are some space in the leaf tree, no
2467                          *  need to account for leaf block credit
2468                          *
2469                          *  bitmaps and block group descriptor blocks
2470                          *  and other metadata blocks still need to be
2471                          *  accounted.
2472                          */
2473                         /* 1 bitmap, 1 block group descriptor */
2474                         ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb);
2475                         return ret;
2476                 }
2477         }
2478
2479         return ext4_chunk_trans_blocks(inode, nrblocks);
2480 }
2481
2482 /*
2483  * How many index/leaf blocks need to change/allocate to add @extents extents?
2484  *
2485  * If we add a single extent, then in the worse case, each tree level
2486  * index/leaf need to be changed in case of the tree split.
2487  *
2488  * If more extents are inserted, they could cause the whole tree split more
2489  * than once, but this is really rare.
2490  */
2491 int ext4_ext_index_trans_blocks(struct inode *inode, int extents)
2492 {
2493         int index;
2494         int depth;
2495
2496         /* If we are converting the inline data, only one is needed here. */
2497         if (ext4_has_inline_data(inode))
2498                 return 1;
2499
2500         depth = ext_depth(inode);
2501
2502         if (extents <= 1)
2503                 index = depth * 2;
2504         else
2505                 index = depth * 3;
2506
2507         return index;
2508 }
2509
2510 static inline int get_default_free_blocks_flags(struct inode *inode)
2511 {
2512         if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode) ||
2513             ext4_test_inode_flag(inode, EXT4_INODE_EA_INODE))
2514                 return EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET;
2515         else if (ext4_should_journal_data(inode))
2516                 return EXT4_FREE_BLOCKS_FORGET;
2517         return 0;
2518 }
2519
2520 /*
2521  * ext4_rereserve_cluster - increment the reserved cluster count when
2522  *                          freeing a cluster with a pending reservation
2523  *
2524  * @inode - file containing the cluster
2525  * @lblk - logical block in cluster to be reserved
2526  *
2527  * Increments the reserved cluster count and adjusts quota in a bigalloc
2528  * file system when freeing a partial cluster containing at least one
2529  * delayed and unwritten block.  A partial cluster meeting that
2530  * requirement will have a pending reservation.  If so, the
2531  * RERESERVE_CLUSTER flag is used when calling ext4_free_blocks() to
2532  * defer reserved and allocated space accounting to a subsequent call
2533  * to this function.
2534  */
2535 static void ext4_rereserve_cluster(struct inode *inode, ext4_lblk_t lblk)
2536 {
2537         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2538         struct ext4_inode_info *ei = EXT4_I(inode);
2539
2540         dquot_reclaim_block(inode, EXT4_C2B(sbi, 1));
2541
2542         spin_lock(&ei->i_block_reservation_lock);
2543         ei->i_reserved_data_blocks++;
2544         percpu_counter_add(&sbi->s_dirtyclusters_counter, 1);
2545         spin_unlock(&ei->i_block_reservation_lock);
2546
2547         percpu_counter_add(&sbi->s_freeclusters_counter, 1);
2548         ext4_remove_pending(inode, lblk);
2549 }
2550
2551 static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
2552                               struct ext4_extent *ex,
2553                               struct partial_cluster *partial,
2554                               ext4_lblk_t from, ext4_lblk_t to)
2555 {
2556         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2557         unsigned short ee_len = ext4_ext_get_actual_len(ex);
2558         ext4_fsblk_t last_pblk, pblk;
2559         ext4_lblk_t num;
2560         int flags;
2561
2562         /* only extent tail removal is allowed */
2563         if (from < le32_to_cpu(ex->ee_block) ||
2564             to != le32_to_cpu(ex->ee_block) + ee_len - 1) {
2565                 ext4_error(sbi->s_sb,
2566                            "strange request: removal(2) %u-%u from %u:%u",
2567                            from, to, le32_to_cpu(ex->ee_block), ee_len);
2568                 return 0;
2569         }
2570
2571 #ifdef EXTENTS_STATS
2572         spin_lock(&sbi->s_ext_stats_lock);
2573         sbi->s_ext_blocks += ee_len;
2574         sbi->s_ext_extents++;
2575         if (ee_len < sbi->s_ext_min)
2576                 sbi->s_ext_min = ee_len;
2577         if (ee_len > sbi->s_ext_max)
2578                 sbi->s_ext_max = ee_len;
2579         if (ext_depth(inode) > sbi->s_depth_max)
2580                 sbi->s_depth_max = ext_depth(inode);
2581         spin_unlock(&sbi->s_ext_stats_lock);
2582 #endif
2583
2584         trace_ext4_remove_blocks(inode, ex, from, to, partial);
2585
2586         /*
2587          * if we have a partial cluster, and it's different from the
2588          * cluster of the last block in the extent, we free it
2589          */
2590         last_pblk = ext4_ext_pblock(ex) + ee_len - 1;
2591
2592         if (partial->state != initial &&
2593             partial->pclu != EXT4_B2C(sbi, last_pblk)) {
2594                 if (partial->state == tofree) {
2595                         flags = get_default_free_blocks_flags(inode);
2596                         if (ext4_is_pending(inode, partial->lblk))
2597                                 flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
2598                         ext4_free_blocks(handle, inode, NULL,
2599                                          EXT4_C2B(sbi, partial->pclu),
2600                                          sbi->s_cluster_ratio, flags);
2601                         if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
2602                                 ext4_rereserve_cluster(inode, partial->lblk);
2603                 }
2604                 partial->state = initial;
2605         }
2606
2607         num = le32_to_cpu(ex->ee_block) + ee_len - from;
2608         pblk = ext4_ext_pblock(ex) + ee_len - num;
2609
2610         /*
2611          * We free the partial cluster at the end of the extent (if any),
2612          * unless the cluster is used by another extent (partial_cluster
2613          * state is nofree).  If a partial cluster exists here, it must be
2614          * shared with the last block in the extent.
2615          */
2616         flags = get_default_free_blocks_flags(inode);
2617
2618         /* partial, left end cluster aligned, right end unaligned */
2619         if ((EXT4_LBLK_COFF(sbi, to) != sbi->s_cluster_ratio - 1) &&
2620             (EXT4_LBLK_CMASK(sbi, to) >= from) &&
2621             (partial->state != nofree)) {
2622                 if (ext4_is_pending(inode, to))
2623                         flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
2624                 ext4_free_blocks(handle, inode, NULL,
2625                                  EXT4_PBLK_CMASK(sbi, last_pblk),
2626                                  sbi->s_cluster_ratio, flags);
2627                 if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
2628                         ext4_rereserve_cluster(inode, to);
2629                 partial->state = initial;
2630                 flags = get_default_free_blocks_flags(inode);
2631         }
2632
2633         flags |= EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER;
2634
2635         /*
2636          * For bigalloc file systems, we never free a partial cluster
2637          * at the beginning of the extent.  Instead, we check to see if we
2638          * need to free it on a subsequent call to ext4_remove_blocks,
2639          * or at the end of ext4_ext_rm_leaf or ext4_ext_remove_space.
2640          */
2641         flags |= EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER;
2642         ext4_free_blocks(handle, inode, NULL, pblk, num, flags);
2643
2644         /* reset the partial cluster if we've freed past it */
2645         if (partial->state != initial && partial->pclu != EXT4_B2C(sbi, pblk))
2646                 partial->state = initial;
2647
2648         /*
2649          * If we've freed the entire extent but the beginning is not left
2650          * cluster aligned and is not marked as ineligible for freeing we
2651          * record the partial cluster at the beginning of the extent.  It
2652          * wasn't freed by the preceding ext4_free_blocks() call, and we
2653          * need to look farther to the left to determine if it's to be freed
2654          * (not shared with another extent). Else, reset the partial
2655          * cluster - we're either  done freeing or the beginning of the
2656          * extent is left cluster aligned.
2657          */
2658         if (EXT4_LBLK_COFF(sbi, from) && num == ee_len) {
2659                 if (partial->state == initial) {
2660                         partial->pclu = EXT4_B2C(sbi, pblk);
2661                         partial->lblk = from;
2662                         partial->state = tofree;
2663                 }
2664         } else {
2665                 partial->state = initial;
2666         }
2667
2668         return 0;
2669 }
2670
2671 /*
2672  * ext4_ext_rm_leaf() Removes the extents associated with the
2673  * blocks appearing between "start" and "end".  Both "start"
2674  * and "end" must appear in the same extent or EIO is returned.
2675  *
2676  * @handle: The journal handle
2677  * @inode:  The files inode
2678  * @path:   The path to the leaf
2679  * @partial_cluster: The cluster which we'll have to free if all extents
2680  *                   has been released from it.  However, if this value is
2681  *                   negative, it's a cluster just to the right of the
2682  *                   punched region and it must not be freed.
2683  * @start:  The first block to remove
2684  * @end:   The last block to remove
2685  */
2686 static int
2687 ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
2688                  struct ext4_ext_path *path,
2689                  struct partial_cluster *partial,
2690                  ext4_lblk_t start, ext4_lblk_t end)
2691 {
2692         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2693         int err = 0, correct_index = 0;
2694         int depth = ext_depth(inode), credits, revoke_credits;
2695         struct ext4_extent_header *eh;
2696         ext4_lblk_t a, b;
2697         unsigned num;
2698         ext4_lblk_t ex_ee_block;
2699         unsigned short ex_ee_len;
2700         unsigned unwritten = 0;
2701         struct ext4_extent *ex;
2702         ext4_fsblk_t pblk;
2703
2704         /* the header must be checked already in ext4_ext_remove_space() */
2705         ext_debug("truncate since %u in leaf to %u\n", start, end);
2706         if (!path[depth].p_hdr)
2707                 path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);
2708         eh = path[depth].p_hdr;
2709         if (unlikely(path[depth].p_hdr == NULL)) {
2710                 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2711                 return -EFSCORRUPTED;
2712         }
2713         /* find where to start removing */
2714         ex = path[depth].p_ext;
2715         if (!ex)
2716                 ex = EXT_LAST_EXTENT(eh);
2717
2718         ex_ee_block = le32_to_cpu(ex->ee_block);
2719         ex_ee_len = ext4_ext_get_actual_len(ex);
2720
2721         trace_ext4_ext_rm_leaf(inode, start, ex, partial);
2722
2723         while (ex >= EXT_FIRST_EXTENT(eh) &&
2724                         ex_ee_block + ex_ee_len > start) {
2725
2726                 if (ext4_ext_is_unwritten(ex))
2727                         unwritten = 1;
2728                 else
2729                         unwritten = 0;
2730
2731                 ext_debug("remove ext %u:[%d]%d\n", ex_ee_block,
2732                           unwritten, ex_ee_len);
2733                 path[depth].p_ext = ex;
2734
2735                 a = ex_ee_block > start ? ex_ee_block : start;
2736                 b = ex_ee_block+ex_ee_len - 1 < end ?
2737                         ex_ee_block+ex_ee_len - 1 : end;
2738
2739                 ext_debug("  border %u:%u\n", a, b);
2740
2741                 /* If this extent is beyond the end of the hole, skip it */
2742                 if (end < ex_ee_block) {
2743                         /*
2744                          * We're going to skip this extent and move to another,
2745                          * so note that its first cluster is in use to avoid
2746                          * freeing it when removing blocks.  Eventually, the
2747                          * right edge of the truncated/punched region will
2748                          * be just to the left.
2749                          */
2750                         if (sbi->s_cluster_ratio > 1) {
2751                                 pblk = ext4_ext_pblock(ex);
2752                                 partial->pclu = EXT4_B2C(sbi, pblk);
2753                                 partial->state = nofree;
2754                         }
2755                         ex--;
2756                         ex_ee_block = le32_to_cpu(ex->ee_block);
2757                         ex_ee_len = ext4_ext_get_actual_len(ex);
2758                         continue;
2759                 } else if (b != ex_ee_block + ex_ee_len - 1) {
2760                         EXT4_ERROR_INODE(inode,
2761                                          "can not handle truncate %u:%u "
2762                                          "on extent %u:%u",
2763                                          start, end, ex_ee_block,
2764                                          ex_ee_block + ex_ee_len - 1);
2765                         err = -EFSCORRUPTED;
2766                         goto out;
2767                 } else if (a != ex_ee_block) {
2768                         /* remove tail of the extent */
2769                         num = a - ex_ee_block;
2770                 } else {
2771                         /* remove whole extent: excellent! */
2772                         num = 0;
2773                 }
2774                 /*
2775                  * 3 for leaf, sb, and inode plus 2 (bmap and group
2776                  * descriptor) for each block group; assume two block
2777                  * groups plus ex_ee_len/blocks_per_block_group for
2778                  * the worst case
2779                  */
2780                 credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb));
2781                 if (ex == EXT_FIRST_EXTENT(eh)) {
2782                         correct_index = 1;
2783                         credits += (ext_depth(inode)) + 1;
2784                 }
2785                 credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);
2786                 /*
2787                  * We may end up freeing some index blocks and data from the
2788                  * punched range. Note that partial clusters are accounted for
2789                  * by ext4_free_data_revoke_credits().
2790                  */
2791                 revoke_credits =
2792                         ext4_free_metadata_revoke_credits(inode->i_sb,
2793                                                           ext_depth(inode)) +
2794                         ext4_free_data_revoke_credits(inode, b - a + 1);
2795
2796                 err = ext4_datasem_ensure_credits(handle, inode, credits,
2797                                                   credits, revoke_credits);
2798                 if (err) {
2799                         if (err > 0)
2800                                 err = -EAGAIN;
2801                         goto out;
2802                 }
2803
2804                 err = ext4_ext_get_access(handle, inode, path + depth);
2805                 if (err)
2806                         goto out;
2807
2808                 err = ext4_remove_blocks(handle, inode, ex, partial, a, b);
2809                 if (err)
2810                         goto out;
2811
2812                 if (num == 0)
2813                         /* this extent is removed; mark slot entirely unused */
2814                         ext4_ext_store_pblock(ex, 0);
2815
2816                 ex->ee_len = cpu_to_le16(num);
2817                 /*
2818                  * Do not mark unwritten if all the blocks in the
2819                  * extent have been removed.
2820                  */
2821                 if (unwritten && num)
2822                         ext4_ext_mark_unwritten(ex);
2823                 /*
2824                  * If the extent was completely released,
2825                  * we need to remove it from the leaf
2826                  */
2827                 if (num == 0) {
2828                         if (end != EXT_MAX_BLOCKS - 1) {
2829                                 /*
2830                                  * For hole punching, we need to scoot all the
2831                                  * extents up when an extent is removed so that
2832                                  * we dont have blank extents in the middle
2833                                  */
2834                                 memmove(ex, ex+1, (EXT_LAST_EXTENT(eh) - ex) *
2835                                         sizeof(struct ext4_extent));
2836
2837                                 /* Now get rid of the one at the end */
2838                                 memset(EXT_LAST_EXTENT(eh), 0,
2839                                         sizeof(struct ext4_extent));
2840                         }
2841                         le16_add_cpu(&eh->eh_entries, -1);
2842                 }
2843
2844                 err = ext4_ext_dirty(handle, inode, path + depth);
2845                 if (err)
2846                         goto out;
2847
2848                 ext_debug("new extent: %u:%u:%llu\n", ex_ee_block, num,
2849                                 ext4_ext_pblock(ex));
2850                 ex--;
2851                 ex_ee_block = le32_to_cpu(ex->ee_block);
2852                 ex_ee_len = ext4_ext_get_actual_len(ex);
2853         }
2854
2855         if (correct_index && eh->eh_entries)
2856                 err = ext4_ext_correct_indexes(handle, inode, path);
2857
2858         /*
2859          * If there's a partial cluster and at least one extent remains in
2860          * the leaf, free the partial cluster if it isn't shared with the
2861          * current extent.  If it is shared with the current extent
2862          * we reset the partial cluster because we've reached the start of the
2863          * truncated/punched region and we're done removing blocks.
2864          */
2865         if (partial->state == tofree && ex >= EXT_FIRST_EXTENT(eh)) {
2866                 pblk = ext4_ext_pblock(ex) + ex_ee_len - 1;
2867                 if (partial->pclu != EXT4_B2C(sbi, pblk)) {
2868                         int flags = get_default_free_blocks_flags(inode);
2869
2870                         if (ext4_is_pending(inode, partial->lblk))
2871                                 flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
2872                         ext4_free_blocks(handle, inode, NULL,
2873                                          EXT4_C2B(sbi, partial->pclu),
2874                                          sbi->s_cluster_ratio, flags);
2875                         if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
2876                                 ext4_rereserve_cluster(inode, partial->lblk);
2877                 }
2878                 partial->state = initial;
2879         }
2880
2881         /* if this leaf is free, then we should
2882          * remove it from index block above */
2883         if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)
2884                 err = ext4_ext_rm_idx(handle, inode, path, depth);
2885
2886 out:
2887         return err;
2888 }
2889
2890 /*
2891  * ext4_ext_more_to_rm:
2892  * returns 1 if current index has to be freed (even partial)
2893  */
2894 static int
2895 ext4_ext_more_to_rm(struct ext4_ext_path *path)
2896 {
2897         BUG_ON(path->p_idx == NULL);
2898
2899         if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr))
2900                 return 0;
2901
2902         /*
2903          * if truncate on deeper level happened, it wasn't partial,
2904          * so we have to consider current index for truncation
2905          */
2906         if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block)
2907                 return 0;
2908         return 1;
2909 }
2910
2911 int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start,
2912                           ext4_lblk_t end)
2913 {
2914         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2915         int depth = ext_depth(inode);
2916         struct ext4_ext_path *path = NULL;
2917         struct partial_cluster partial;
2918         handle_t *handle;
2919         int i = 0, err = 0;
2920
2921         partial.pclu = 0;
2922         partial.lblk = 0;
2923         partial.state = initial;
2924
2925         ext_debug("truncate since %u to %u\n", start, end);
2926
2927         /* probably first extent we're gonna free will be last in block */
2928         handle = ext4_journal_start_with_revoke(inode, EXT4_HT_TRUNCATE,
2929                         depth + 1,
2930                         ext4_free_metadata_revoke_credits(inode->i_sb, depth));
2931         if (IS_ERR(handle))
2932                 return PTR_ERR(handle);
2933
2934 again:
2935         trace_ext4_ext_remove_space(inode, start, end, depth);
2936
2937         /*
2938          * Check if we are removing extents inside the extent tree. If that
2939          * is the case, we are going to punch a hole inside the extent tree
2940          * so we have to check whether we need to split the extent covering
2941          * the last block to remove so we can easily remove the part of it
2942          * in ext4_ext_rm_leaf().
2943          */
2944         if (end < EXT_MAX_BLOCKS - 1) {
2945                 struct ext4_extent *ex;
2946                 ext4_lblk_t ee_block, ex_end, lblk;
2947                 ext4_fsblk_t pblk;
2948
2949                 /* find extent for or closest extent to this block */
2950                 path = ext4_find_extent(inode, end, NULL, EXT4_EX_NOCACHE);
2951                 if (IS_ERR(path)) {
2952                         ext4_journal_stop(handle);
2953                         return PTR_ERR(path);
2954                 }
2955                 depth = ext_depth(inode);
2956                 /* Leaf not may not exist only if inode has no blocks at all */
2957                 ex = path[depth].p_ext;
2958                 if (!ex) {
2959                         if (depth) {
2960                                 EXT4_ERROR_INODE(inode,
2961                                                  "path[%d].p_hdr == NULL",
2962                                                  depth);
2963                                 err = -EFSCORRUPTED;
2964                         }
2965                         goto out;
2966                 }
2967
2968                 ee_block = le32_to_cpu(ex->ee_block);
2969                 ex_end = ee_block + ext4_ext_get_actual_len(ex) - 1;
2970
2971                 /*
2972                  * See if the last block is inside the extent, if so split
2973                  * the extent at 'end' block so we can easily remove the
2974                  * tail of the first part of the split extent in
2975                  * ext4_ext_rm_leaf().
2976                  */
2977                 if (end >= ee_block && end < ex_end) {
2978
2979                         /*
2980                          * If we're going to split the extent, note that
2981                          * the cluster containing the block after 'end' is
2982                          * in use to avoid freeing it when removing blocks.
2983                          */
2984                         if (sbi->s_cluster_ratio > 1) {
2985                                 pblk = ext4_ext_pblock(ex) + end - ee_block + 2;
2986                                 partial.pclu = EXT4_B2C(sbi, pblk);
2987                                 partial.state = nofree;
2988                         }
2989
2990                         /*
2991                          * Split the extent in two so that 'end' is the last
2992                          * block in the first new extent. Also we should not
2993                          * fail removing space due to ENOSPC so try to use
2994                          * reserved block if that happens.
2995                          */
2996                         err = ext4_force_split_extent_at(handle, inode, &path,
2997                                                          end + 1, 1);
2998                         if (err < 0)
2999                                 goto out;
3000
3001                 } else if (sbi->s_cluster_ratio > 1 && end >= ex_end &&
3002                            partial.state == initial) {
3003                         /*
3004                          * If we're punching, there's an extent to the right.
3005                          * If the partial cluster hasn't been set, set it to
3006                          * that extent's first cluster and its state to nofree
3007                          * so it won't be freed should it contain blocks to be
3008                          * removed. If it's already set (tofree/nofree), we're
3009                          * retrying and keep the original partial cluster info
3010                          * so a cluster marked tofree as a result of earlier
3011                          * extent removal is not lost.
3012                          */
3013                         lblk = ex_end + 1;
3014                         err = ext4_ext_search_right(inode, path, &lblk, &pblk,
3015                                                     &ex);
3016                         if (err)
3017                                 goto out;
3018                         if (pblk) {
3019                                 partial.pclu = EXT4_B2C(sbi, pblk);
3020                                 partial.state = nofree;
3021                         }
3022                 }
3023         }
3024         /*
3025          * We start scanning from right side, freeing all the blocks
3026          * after i_size and walking into the tree depth-wise.
3027          */
3028         depth = ext_depth(inode);
3029         if (path) {
3030                 int k = i = depth;
3031                 while (--k > 0)
3032                         path[k].p_block =
3033                                 le16_to_cpu(path[k].p_hdr->eh_entries)+1;
3034         } else {
3035                 path = kcalloc(depth + 1, sizeof(struct ext4_ext_path),
3036                                GFP_NOFS);
3037                 if (path == NULL) {
3038                         ext4_journal_stop(handle);
3039                         return -ENOMEM;
3040                 }
3041                 path[0].p_maxdepth = path[0].p_depth = depth;
3042                 path[0].p_hdr = ext_inode_hdr(inode);
3043                 i = 0;
3044
3045                 if (ext4_ext_check(inode, path[0].p_hdr, depth, 0)) {
3046                         err = -EFSCORRUPTED;
3047                         goto out;
3048                 }
3049         }
3050         err = 0;
3051
3052         while (i >= 0 && err == 0) {
3053                 if (i == depth) {
3054                         /* this is leaf block */
3055                         err = ext4_ext_rm_leaf(handle, inode, path,
3056                                                &partial, start, end);
3057                         /* root level has p_bh == NULL, brelse() eats this */
3058                         brelse(path[i].p_bh);
3059                         path[i].p_bh = NULL;
3060                         i--;
3061                         continue;
3062                 }
3063
3064                 /* this is index block */
3065                 if (!path[i].p_hdr) {
3066                         ext_debug("initialize header\n");
3067                         path[i].p_hdr = ext_block_hdr(path[i].p_bh);
3068                 }
3069
3070                 if (!path[i].p_idx) {
3071                         /* this level hasn't been touched yet */
3072                         path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);
3073                         path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1;
3074                         ext_debug("init index ptr: hdr 0x%p, num %d\n",
3075                                   path[i].p_hdr,
3076                                   le16_to_cpu(path[i].p_hdr->eh_entries));
3077                 } else {
3078                         /* we were already here, see at next index */
3079                         path[i].p_idx--;
3080                 }
3081
3082                 ext_debug("level %d - index, first 0x%p, cur 0x%p\n",
3083                                 i, EXT_FIRST_INDEX(path[i].p_hdr),
3084                                 path[i].p_idx);
3085                 if (ext4_ext_more_to_rm(path + i)) {
3086                         struct buffer_head *bh;
3087                         /* go to the next level */
3088                         ext_debug("move to level %d (block %llu)\n",
3089                                   i + 1, ext4_idx_pblock(path[i].p_idx));
3090                         memset(path + i + 1, 0, sizeof(*path));
3091                         bh = read_extent_tree_block(inode,
3092                                 ext4_idx_pblock(path[i].p_idx), depth - i - 1,
3093                                 EXT4_EX_NOCACHE);
3094                         if (IS_ERR(bh)) {
3095                                 /* should we reset i_size? */
3096                                 err = PTR_ERR(bh);
3097                                 break;
3098                         }
3099                         /* Yield here to deal with large extent trees.
3100                          * Should be a no-op if we did IO above. */
3101                         cond_resched();
3102                         if (WARN_ON(i + 1 > depth)) {
3103                                 err = -EFSCORRUPTED;
3104                                 break;
3105                         }
3106                         path[i + 1].p_bh = bh;
3107
3108                         /* save actual number of indexes since this
3109                          * number is changed at the next iteration */
3110                         path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries);
3111                         i++;
3112                 } else {
3113                         /* we finished processing this index, go up */
3114                         if (path[i].p_hdr->eh_entries == 0 && i > 0) {
3115                                 /* index is empty, remove it;
3116                                  * handle must be already prepared by the
3117                                  * truncatei_leaf() */
3118                                 err = ext4_ext_rm_idx(handle, inode, path, i);
3119                         }
3120                         /* root level has p_bh == NULL, brelse() eats this */
3121                         brelse(path[i].p_bh);
3122                         path[i].p_bh = NULL;
3123                         i--;
3124                         ext_debug("return to level %d\n", i);
3125                 }
3126         }
3127
3128         trace_ext4_ext_remove_space_done(inode, start, end, depth, &partial,
3129                                          path->p_hdr->eh_entries);
3130
3131         /*
3132          * if there's a partial cluster and we have removed the first extent
3133          * in the file, then we also free the partial cluster, if any
3134          */
3135         if (partial.state == tofree && err == 0) {
3136                 int flags = get_default_free_blocks_flags(inode);
3137
3138                 if (ext4_is_pending(inode, partial.lblk))
3139                         flags |= EXT4_FREE_BLOCKS_RERESERVE_CLUSTER;
3140                 ext4_free_blocks(handle, inode, NULL,
3141                                  EXT4_C2B(sbi, partial.pclu),
3142                                  sbi->s_cluster_ratio, flags);
3143                 if (flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)
3144                         ext4_rereserve_cluster(inode, partial.lblk);
3145                 partial.state = initial;
3146         }
3147
3148         /* TODO: flexible tree reduction should be here */
3149         if (path->p_hdr->eh_entries == 0) {
3150                 /*
3151                  * truncate to zero freed all the tree,
3152                  * so we need to correct eh_depth
3153                  */
3154                 err = ext4_ext_get_access(handle, inode, path);
3155                 if (err == 0) {
3156                         ext_inode_hdr(inode)->eh_depth = 0;
3157                         ext_inode_hdr(inode)->eh_max =
3158                                 cpu_to_le16(ext4_ext_space_root(inode, 0));
3159                         err = ext4_ext_dirty(handle, inode, path);
3160                 }
3161         }
3162 out:
3163         ext4_ext_drop_refs(path);
3164         kfree(path);
3165         path = NULL;
3166         if (err == -EAGAIN)
3167                 goto again;
3168         ext4_journal_stop(handle);
3169
3170         return err;
3171 }
3172
3173 /*
3174  * called at mount time
3175  */
3176 void ext4_ext_init(struct super_block *sb)
3177 {
3178         /*
3179          * possible initialization would be here
3180          */
3181
3182         if (ext4_has_feature_extents(sb)) {
3183 #if defined(AGGRESSIVE_TEST) || defined(CHECK_BINSEARCH) || defined(EXTENTS_STATS)
3184                 printk(KERN_INFO "EXT4-fs: file extents enabled"
3185 #ifdef AGGRESSIVE_TEST
3186                        ", aggressive tests"
3187 #endif
3188 #ifdef CHECK_BINSEARCH
3189                        ", check binsearch"
3190 #endif
3191 #ifdef EXTENTS_STATS
3192                        ", stats"
3193 #endif
3194                        "\n");
3195 #endif
3196 #ifdef EXTENTS_STATS
3197                 spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock);
3198                 EXT4_SB(sb)->s_ext_min = 1 << 30;
3199                 EXT4_SB(sb)->s_ext_max = 0;
3200 #endif
3201         }
3202 }
3203
3204 /*
3205  * called at umount time
3206  */
3207 void ext4_ext_release(struct super_block *sb)
3208 {
3209         if (!ext4_has_feature_extents(sb))
3210                 return;
3211
3212 #ifdef EXTENTS_STATS
3213         if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) {
3214                 struct ext4_sb_info *sbi = EXT4_SB(sb);
3215                 printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n",
3216                         sbi->s_ext_blocks, sbi->s_ext_extents,
3217                         sbi->s_ext_blocks / sbi->s_ext_extents);
3218                 printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n",
3219                         sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max);
3220         }
3221 #endif
3222 }
3223
3224 static int ext4_zeroout_es(struct inode *inode, struct ext4_extent *ex)
3225 {
3226         ext4_lblk_t  ee_block;
3227         ext4_fsblk_t ee_pblock;
3228         unsigned int ee_len;
3229
3230         ee_block  = le32_to_cpu(ex->ee_block);
3231         ee_len    = ext4_ext_get_actual_len(ex);
3232         ee_pblock = ext4_ext_pblock(ex);
3233
3234         if (ee_len == 0)
3235                 return 0;
3236
3237         return ext4_es_insert_extent(inode, ee_block, ee_len, ee_pblock,
3238                                      EXTENT_STATUS_WRITTEN);
3239 }
3240
3241 /* FIXME!! we need to try to merge to left or right after zero-out  */
3242 static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex)
3243 {
3244         ext4_fsblk_t ee_pblock;
3245         unsigned int ee_len;
3246
3247         ee_len    = ext4_ext_get_actual_len(ex);
3248         ee_pblock = ext4_ext_pblock(ex);
3249         return ext4_issue_zeroout(inode, le32_to_cpu(ex->ee_block), ee_pblock,
3250                                   ee_len);
3251 }
3252
3253 /*
3254  * ext4_split_extent_at() splits an extent at given block.
3255  *
3256  * @handle: the journal handle
3257  * @inode: the file inode
3258  * @path: the path to the extent
3259  * @split: the logical block where the extent is splitted.
3260  * @split_flags: indicates if the extent could be zeroout if split fails, and
3261  *               the states(init or unwritten) of new extents.
3262  * @flags: flags used to insert new extent to extent tree.
3263  *
3264  *
3265  * Splits extent [a, b] into two extents [a, @split) and [@split, b], states
3266  * of which are deterimined by split_flag.
3267  *
3268  * There are two cases:
3269  *  a> the extent are splitted into two extent.
3270  *  b> split is not needed, and just mark the extent.
3271  *
3272  * return 0 on success.
3273  */
3274 static int ext4_split_extent_at(handle_t *handle,
3275                              struct inode *inode,
3276                              struct ext4_ext_path **ppath,
3277                              ext4_lblk_t split,
3278                              int split_flag,
3279                              int flags)
3280 {
3281         struct ext4_ext_path *path = *ppath;
3282         ext4_fsblk_t newblock;
3283         ext4_lblk_t ee_block;
3284         struct ext4_extent *ex, newex, orig_ex, zero_ex;
3285         struct ext4_extent *ex2 = NULL;
3286         unsigned int ee_len, depth;
3287         int err = 0;
3288
3289         BUG_ON((split_flag & (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2)) ==
3290                (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2));
3291
3292         ext_debug("ext4_split_extents_at: inode %lu, logical"
3293                 "block %llu\n", inode->i_ino, (unsigned long long)split);
3294
3295         ext4_ext_show_leaf(inode, path);
3296
3297         depth = ext_depth(inode);
3298         ex = path[depth].p_ext;
3299         ee_block = le32_to_cpu(ex->ee_block);
3300         ee_len = ext4_ext_get_actual_len(ex);
3301         newblock = split - ee_block + ext4_ext_pblock(ex);
3302
3303         BUG_ON(split < ee_block || split >= (ee_block + ee_len));
3304         BUG_ON(!ext4_ext_is_unwritten(ex) &&
3305                split_flag & (EXT4_EXT_MAY_ZEROOUT |
3306                              EXT4_EXT_MARK_UNWRIT1 |
3307                              EXT4_EXT_MARK_UNWRIT2));
3308
3309         err = ext4_ext_get_access(handle, inode, path + depth);
3310         if (err)
3311                 goto out;
3312
3313         if (split == ee_block) {
3314                 /*
3315                  * case b: block @split is the block that the extent begins with
3316                  * then we just change the state of the extent, and splitting
3317                  * is not needed.
3318                  */
3319                 if (split_flag & EXT4_EXT_MARK_UNWRIT2)
3320                         ext4_ext_mark_unwritten(ex);
3321                 else
3322                         ext4_ext_mark_initialized(ex);
3323
3324                 if (!(flags & EXT4_GET_BLOCKS_PRE_IO))
3325                         ext4_ext_try_to_merge(handle, inode, path, ex);
3326
3327                 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3328                 goto out;
3329         }
3330
3331         /* case a */
3332         memcpy(&orig_ex, ex, sizeof(orig_ex));
3333         ex->ee_len = cpu_to_le16(split - ee_block);
3334         if (split_flag & EXT4_EXT_MARK_UNWRIT1)
3335                 ext4_ext_mark_unwritten(ex);
3336
3337         /*
3338          * path may lead to new leaf, not to original leaf any more
3339          * after ext4_ext_insert_extent() returns,
3340          */
3341         err = ext4_ext_dirty(handle, inode, path + depth);
3342         if (err)
3343                 goto fix_extent_len;
3344
3345         ex2 = &newex;
3346         ex2->ee_block = cpu_to_le32(split);
3347         ex2->ee_len   = cpu_to_le16(ee_len - (split - ee_block));
3348         ext4_ext_store_pblock(ex2, newblock);
3349         if (split_flag & EXT4_EXT_MARK_UNWRIT2)
3350                 ext4_ext_mark_unwritten(ex2);
3351
3352         err = ext4_ext_insert_extent(handle, inode, ppath, &newex, flags);
3353         if (err == -ENOSPC && (EXT4_EXT_MAY_ZEROOUT & split_flag)) {
3354                 if (split_flag & (EXT4_EXT_DATA_VALID1|EXT4_EXT_DATA_VALID2)) {
3355                         if (split_flag & EXT4_EXT_DATA_VALID1) {
3356                                 err = ext4_ext_zeroout(inode, ex2);
3357                                 zero_ex.ee_block = ex2->ee_block;
3358                                 zero_ex.ee_len = cpu_to_le16(
3359                                                 ext4_ext_get_actual_len(ex2));
3360                                 ext4_ext_store_pblock(&zero_ex,
3361                                                       ext4_ext_pblock(ex2));
3362                         } else {
3363                                 err = ext4_ext_zeroout(inode, ex);
3364                                 zero_ex.ee_block = ex->ee_block;
3365                                 zero_ex.ee_len = cpu_to_le16(
3366                                                 ext4_ext_get_actual_len(ex));
3367                                 ext4_ext_store_pblock(&zero_ex,
3368                                                       ext4_ext_pblock(ex));
3369                         }
3370                 } else {
3371                         err = ext4_ext_zeroout(inode, &orig_ex);
3372                         zero_ex.ee_block = orig_ex.ee_block;
3373                         zero_ex.ee_len = cpu_to_le16(
3374                                                 ext4_ext_get_actual_len(&orig_ex));
3375                         ext4_ext_store_pblock(&zero_ex,
3376                                               ext4_ext_pblock(&orig_ex));
3377                 }
3378
3379                 if (err)
3380                         goto fix_extent_len;
3381                 /* update the extent length and mark as initialized */
3382                 ex->ee_len = cpu_to_le16(ee_len);
3383                 ext4_ext_try_to_merge(handle, inode, path, ex);
3384                 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3385                 if (err)
3386                         goto fix_extent_len;
3387
3388                 /* update extent status tree */
3389                 err = ext4_zeroout_es(inode, &zero_ex);
3390
3391                 goto out;
3392         } else if (err)
3393                 goto fix_extent_len;
3394
3395 out:
3396         ext4_ext_show_leaf(inode, path);
3397         return err;
3398
3399 fix_extent_len:
3400         ex->ee_len = orig_ex.ee_len;
3401         ext4_ext_dirty(handle, inode, path + path->p_depth);
3402         return err;
3403 }
3404
3405 /*
3406  * ext4_split_extents() splits an extent and mark extent which is covered
3407  * by @map as split_flags indicates
3408  *
3409  * It may result in splitting the extent into multiple extents (up to three)
3410  * There are three possibilities:
3411  *   a> There is no split required
3412  *   b> Splits in two extents: Split is happening at either end of the extent
3413  *   c> Splits in three extents: Somone is splitting in middle of the extent
3414  *
3415  */
3416 static int ext4_split_extent(handle_t *handle,
3417                               struct inode *inode,
3418                               struct ext4_ext_path **ppath,
3419                               struct ext4_map_blocks *map,
3420                               int split_flag,
3421                               int flags)
3422 {
3423         struct ext4_ext_path *path = *ppath;
3424         ext4_lblk_t ee_block;
3425         struct ext4_extent *ex;
3426         unsigned int ee_len, depth;
3427         int err = 0;
3428         int unwritten;
3429         int split_flag1, flags1;
3430         int allocated = map->m_len;
3431
3432         depth = ext_depth(inode);
3433         ex = path[depth].p_ext;
3434         ee_block = le32_to_cpu(ex->ee_block);
3435         ee_len = ext4_ext_get_actual_len(ex);
3436         unwritten = ext4_ext_is_unwritten(ex);
3437
3438         if (map->m_lblk + map->m_len < ee_block + ee_len) {
3439                 split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT;
3440                 flags1 = flags | EXT4_GET_BLOCKS_PRE_IO;
3441                 if (unwritten)
3442                         split_flag1 |= EXT4_EXT_MARK_UNWRIT1 |
3443                                        EXT4_EXT_MARK_UNWRIT2;
3444                 if (split_flag & EXT4_EXT_DATA_VALID2)
3445                         split_flag1 |= EXT4_EXT_DATA_VALID1;
3446                 err = ext4_split_extent_at(handle, inode, ppath,
3447                                 map->m_lblk + map->m_len, split_flag1, flags1);
3448                 if (err)
3449                         goto out;
3450         } else {
3451                 allocated = ee_len - (map->m_lblk - ee_block);
3452         }
3453         /*
3454          * Update path is required because previous ext4_split_extent_at() may
3455          * result in split of original leaf or extent zeroout.
3456          */
3457         path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3458         if (IS_ERR(path))
3459                 return PTR_ERR(path);
3460         depth = ext_depth(inode);
3461         ex = path[depth].p_ext;
3462         if (!ex) {
3463                 EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
3464                                  (unsigned long) map->m_lblk);
3465                 return -EFSCORRUPTED;
3466         }
3467         unwritten = ext4_ext_is_unwritten(ex);
3468         split_flag1 = 0;
3469
3470         if (map->m_lblk >= ee_block) {
3471                 split_flag1 = split_flag & EXT4_EXT_DATA_VALID2;
3472                 if (unwritten) {
3473                         split_flag1 |= EXT4_EXT_MARK_UNWRIT1;
3474                         split_flag1 |= split_flag & (EXT4_EXT_MAY_ZEROOUT |
3475                                                      EXT4_EXT_MARK_UNWRIT2);
3476                 }
3477                 err = ext4_split_extent_at(handle, inode, ppath,
3478                                 map->m_lblk, split_flag1, flags);
3479                 if (err)
3480                         goto out;
3481         }
3482
3483         ext4_ext_show_leaf(inode, path);
3484 out:
3485         return err ? err : allocated;
3486 }
3487
3488 /*
3489  * This function is called by ext4_ext_map_blocks() if someone tries to write
3490  * to an unwritten extent. It may result in splitting the unwritten
3491  * extent into multiple extents (up to three - one initialized and two
3492  * unwritten).
3493  * There are three possibilities:
3494  *   a> There is no split required: Entire extent should be initialized
3495  *   b> Splits in two extents: Write is happening at either end of the extent
3496  *   c> Splits in three extents: Somone is writing in middle of the extent
3497  *
3498  * Pre-conditions:
3499  *  - The extent pointed to by 'path' is unwritten.
3500  *  - The extent pointed to by 'path' contains a superset
3501  *    of the logical span [map->m_lblk, map->m_lblk + map->m_len).
3502  *
3503  * Post-conditions on success:
3504  *  - the returned value is the number of blocks beyond map->l_lblk
3505  *    that are allocated and initialized.
3506  *    It is guaranteed to be >= map->m_len.
3507  */
3508 static int ext4_ext_convert_to_initialized(handle_t *handle,
3509                                            struct inode *inode,
3510                                            struct ext4_map_blocks *map,
3511                                            struct ext4_ext_path **ppath,
3512                                            int flags)
3513 {
3514         struct ext4_ext_path *path = *ppath;
3515         struct ext4_sb_info *sbi;
3516         struct ext4_extent_header *eh;
3517         struct ext4_map_blocks split_map;
3518         struct ext4_extent zero_ex1, zero_ex2;
3519         struct ext4_extent *ex, *abut_ex;
3520         ext4_lblk_t ee_block, eof_block;
3521         unsigned int ee_len, depth, map_len = map->m_len;
3522         int allocated = 0, max_zeroout = 0;
3523         int err = 0;
3524         int split_flag = EXT4_EXT_DATA_VALID2;
3525
3526         ext_debug("ext4_ext_convert_to_initialized: inode %lu, logical"
3527                 "block %llu, max_blocks %u\n", inode->i_ino,
3528                 (unsigned long long)map->m_lblk, map_len);
3529
3530         sbi = EXT4_SB(inode->i_sb);
3531         eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
3532                 inode->i_sb->s_blocksize_bits;
3533         if (eof_block < map->m_lblk + map_len)
3534                 eof_block = map->m_lblk + map_len;
3535
3536         depth = ext_depth(inode);
3537         eh = path[depth].p_hdr;
3538         ex = path[depth].p_ext;
3539         ee_block = le32_to_cpu(ex->ee_block);
3540         ee_len = ext4_ext_get_actual_len(ex);
3541         zero_ex1.ee_len = 0;
3542         zero_ex2.ee_len = 0;
3543
3544         trace_ext4_ext_convert_to_initialized_enter(inode, map, ex);
3545
3546         /* Pre-conditions */
3547         BUG_ON(!ext4_ext_is_unwritten(ex));
3548         BUG_ON(!in_range(map->m_lblk, ee_block, ee_len));
3549
3550         /*
3551          * Attempt to transfer newly initialized blocks from the currently
3552          * unwritten extent to its neighbor. This is much cheaper
3553          * than an insertion followed by a merge as those involve costly
3554          * memmove() calls. Transferring to the left is the common case in
3555          * steady state for workloads doing fallocate(FALLOC_FL_KEEP_SIZE)
3556          * followed by append writes.
3557          *
3558          * Limitations of the current logic:
3559          *  - L1: we do not deal with writes covering the whole extent.
3560          *    This would require removing the extent if the transfer
3561          *    is possible.
3562          *  - L2: we only attempt to merge with an extent stored in the
3563          *    same extent tree node.
3564          */
3565         if ((map->m_lblk == ee_block) &&
3566                 /* See if we can merge left */
3567                 (map_len < ee_len) &&           /*L1*/
3568                 (ex > EXT_FIRST_EXTENT(eh))) {  /*L2*/
3569                 ext4_lblk_t prev_lblk;
3570                 ext4_fsblk_t prev_pblk, ee_pblk;
3571                 unsigned int prev_len;
3572
3573                 abut_ex = ex - 1;
3574                 prev_lblk = le32_to_cpu(abut_ex->ee_block);
3575                 prev_len = ext4_ext_get_actual_len(abut_ex);
3576                 prev_pblk = ext4_ext_pblock(abut_ex);
3577                 ee_pblk = ext4_ext_pblock(ex);
3578
3579                 /*
3580                  * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3581                  * upon those conditions:
3582                  * - C1: abut_ex is initialized,
3583                  * - C2: abut_ex is logically abutting ex,
3584                  * - C3: abut_ex is physically abutting ex,
3585                  * - C4: abut_ex can receive the additional blocks without
3586                  *   overflowing the (initialized) length limit.
3587                  */
3588                 if ((!ext4_ext_is_unwritten(abut_ex)) &&                /*C1*/
3589                         ((prev_lblk + prev_len) == ee_block) &&         /*C2*/
3590                         ((prev_pblk + prev_len) == ee_pblk) &&          /*C3*/
3591                         (prev_len < (EXT_INIT_MAX_LEN - map_len))) {    /*C4*/
3592                         err = ext4_ext_get_access(handle, inode, path + depth);
3593                         if (err)
3594                                 goto out;
3595
3596                         trace_ext4_ext_convert_to_initialized_fastpath(inode,
3597                                 map, ex, abut_ex);
3598
3599                         /* Shift the start of ex by 'map_len' blocks */
3600                         ex->ee_block = cpu_to_le32(ee_block + map_len);
3601                         ext4_ext_store_pblock(ex, ee_pblk + map_len);
3602                         ex->ee_len = cpu_to_le16(ee_len - map_len);
3603                         ext4_ext_mark_unwritten(ex); /* Restore the flag */
3604
3605                         /* Extend abut_ex by 'map_len' blocks */
3606                         abut_ex->ee_len = cpu_to_le16(prev_len + map_len);
3607
3608                         /* Result: number of initialized blocks past m_lblk */
3609                         allocated = map_len;
3610                 }
3611         } else if (((map->m_lblk + map_len) == (ee_block + ee_len)) &&
3612                    (map_len < ee_len) &&        /*L1*/
3613                    ex < EXT_LAST_EXTENT(eh)) {  /*L2*/
3614                 /* See if we can merge right */
3615                 ext4_lblk_t next_lblk;
3616                 ext4_fsblk_t next_pblk, ee_pblk;
3617                 unsigned int next_len;
3618
3619                 abut_ex = ex + 1;
3620                 next_lblk = le32_to_cpu(abut_ex->ee_block);
3621                 next_len = ext4_ext_get_actual_len(abut_ex);
3622                 next_pblk = ext4_ext_pblock(abut_ex);
3623                 ee_pblk = ext4_ext_pblock(ex);
3624
3625                 /*
3626                  * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3627                  * upon those conditions:
3628                  * - C1: abut_ex is initialized,
3629                  * - C2: abut_ex is logically abutting ex,
3630                  * - C3: abut_ex is physically abutting ex,
3631                  * - C4: abut_ex can receive the additional blocks without
3632                  *   overflowing the (initialized) length limit.
3633                  */
3634                 if ((!ext4_ext_is_unwritten(abut_ex)) &&                /*C1*/
3635                     ((map->m_lblk + map_len) == next_lblk) &&           /*C2*/
3636                     ((ee_pblk + ee_len) == next_pblk) &&                /*C3*/
3637                     (next_len < (EXT_INIT_MAX_LEN - map_len))) {        /*C4*/
3638                         err = ext4_ext_get_access(handle, inode, path + depth);
3639                         if (err)
3640                                 goto out;
3641
3642                         trace_ext4_ext_convert_to_initialized_fastpath(inode,
3643                                 map, ex, abut_ex);
3644
3645                         /* Shift the start of abut_ex by 'map_len' blocks */
3646                         abut_ex->ee_block = cpu_to_le32(next_lblk - map_len);
3647                         ext4_ext_store_pblock(abut_ex, next_pblk - map_len);
3648                         ex->ee_len = cpu_to_le16(ee_len - map_len);
3649                         ext4_ext_mark_unwritten(ex); /* Restore the flag */
3650
3651                         /* Extend abut_ex by 'map_len' blocks */
3652                         abut_ex->ee_len = cpu_to_le16(next_len + map_len);
3653
3654                         /* Result: number of initialized blocks past m_lblk */
3655                         allocated = map_len;
3656                 }
3657         }
3658         if (allocated) {
3659                 /* Mark the block containing both extents as dirty */
3660                 ext4_ext_dirty(handle, inode, path + depth);
3661
3662                 /* Update path to point to the right extent */
3663                 path[depth].p_ext = abut_ex;
3664                 goto out;
3665         } else
3666                 allocated = ee_len - (map->m_lblk - ee_block);
3667
3668         WARN_ON(map->m_lblk < ee_block);
3669         /*
3670          * It is safe to convert extent to initialized via explicit
3671          * zeroout only if extent is fully inside i_size or new_size.
3672          */
3673         split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0;
3674
3675         if (EXT4_EXT_MAY_ZEROOUT & split_flag)
3676                 max_zeroout = sbi->s_extent_max_zeroout_kb >>
3677                         (inode->i_sb->s_blocksize_bits - 10);
3678
3679         /*
3680          * five cases:
3681          * 1. split the extent into three extents.
3682          * 2. split the extent into two extents, zeroout the head of the first
3683          *    extent.
3684          * 3. split the extent into two extents, zeroout the tail of the second
3685          *    extent.
3686          * 4. split the extent into two extents with out zeroout.
3687          * 5. no splitting needed, just possibly zeroout the head and / or the
3688          *    tail of the extent.
3689          */
3690         split_map.m_lblk = map->m_lblk;
3691         split_map.m_len = map->m_len;
3692
3693         if (max_zeroout && (allocated > split_map.m_len)) {
3694                 if (allocated <= max_zeroout) {
3695                         /* case 3 or 5 */
3696                         zero_ex1.ee_block =
3697                                  cpu_to_le32(split_map.m_lblk +
3698                                              split_map.m_len);
3699                         zero_ex1.ee_len =
3700                                 cpu_to_le16(allocated - split_map.m_len);
3701                         ext4_ext_store_pblock(&zero_ex1,
3702                                 ext4_ext_pblock(ex) + split_map.m_lblk +
3703                                 split_map.m_len - ee_block);
3704                         err = ext4_ext_zeroout(inode, &zero_ex1);
3705                         if (err)
3706                                 goto out;
3707                         split_map.m_len = allocated;
3708                 }
3709                 if (split_map.m_lblk - ee_block + split_map.m_len <
3710                                                                 max_zeroout) {
3711                         /* case 2 or 5 */
3712                         if (split_map.m_lblk != ee_block) {
3713                                 zero_ex2.ee_block = ex->ee_block;
3714                                 zero_ex2.ee_len = cpu_to_le16(split_map.m_lblk -
3715                                                         ee_block);
3716                                 ext4_ext_store_pblock(&zero_ex2,
3717                                                       ext4_ext_pblock(ex));
3718                                 err = ext4_ext_zeroout(inode, &zero_ex2);
3719                                 if (err)
3720                                         goto out;
3721                         }
3722
3723                         split_map.m_len += split_map.m_lblk - ee_block;
3724                         split_map.m_lblk = ee_block;
3725                         allocated = map->m_len;
3726                 }
3727         }
3728
3729         err = ext4_split_extent(handle, inode, ppath, &split_map, split_flag,
3730                                 flags);
3731         if (err > 0)
3732                 err = 0;
3733 out:
3734         /* If we have gotten a failure, don't zero out status tree */
3735         if (!err) {
3736                 err = ext4_zeroout_es(inode, &zero_ex1);
3737                 if (!err)
3738                         err = ext4_zeroout_es(inode, &zero_ex2);
3739         }
3740         return err ? err : allocated;
3741 }
3742
3743 /*
3744  * This function is called by ext4_ext_map_blocks() from
3745  * ext4_get_blocks_dio_write() when DIO to write
3746  * to an unwritten extent.
3747  *
3748  * Writing to an unwritten extent may result in splitting the unwritten
3749  * extent into multiple initialized/unwritten extents (up to three)
3750  * There are three possibilities:
3751  *   a> There is no split required: Entire extent should be unwritten
3752  *   b> Splits in two extents: Write is happening at either end of the extent
3753  *   c> Splits in three extents: Somone is writing in middle of the extent
3754  *
3755  * This works the same way in the case of initialized -> unwritten conversion.
3756  *
3757  * One of more index blocks maybe needed if the extent tree grow after
3758  * the unwritten extent split. To prevent ENOSPC occur at the IO
3759  * complete, we need to split the unwritten extent before DIO submit
3760  * the IO. The unwritten extent called at this time will be split
3761  * into three unwritten extent(at most). After IO complete, the part
3762  * being filled will be convert to initialized by the end_io callback function
3763  * via ext4_convert_unwritten_extents().
3764  *
3765  * Returns the size of unwritten extent to be written on success.
3766  */
3767 static int ext4_split_convert_extents(handle_t *handle,
3768                                         struct inode *inode,
3769                                         struct ext4_map_blocks *map,
3770                                         struct ext4_ext_path **ppath,
3771                                         int flags)
3772 {
3773         struct ext4_ext_path *path = *ppath;
3774         ext4_lblk_t eof_block;
3775         ext4_lblk_t ee_block;
3776         struct ext4_extent *ex;
3777         unsigned int ee_len;
3778         int split_flag = 0, depth;
3779
3780         ext_debug("%s: inode %lu, logical block %llu, max_blocks %u\n",
3781                   __func__, inode->i_ino,
3782                   (unsigned long long)map->m_lblk, map->m_len);
3783
3784         eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
3785                 inode->i_sb->s_blocksize_bits;
3786         if (eof_block < map->m_lblk + map->m_len)
3787                 eof_block = map->m_lblk + map->m_len;
3788         /*
3789          * It is safe to convert extent to initialized via explicit
3790          * zeroout only if extent is fully insde i_size or new_size.
3791          */
3792         depth = ext_depth(inode);
3793         ex = path[depth].p_ext;
3794         ee_block = le32_to_cpu(ex->ee_block);
3795         ee_len = ext4_ext_get_actual_len(ex);
3796
3797         /* Convert to unwritten */
3798         if (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN) {
3799                 split_flag |= EXT4_EXT_DATA_VALID1;
3800         /* Convert to initialized */
3801         } else if (flags & EXT4_GET_BLOCKS_CONVERT) {
3802                 split_flag |= ee_block + ee_len <= eof_block ?
3803                               EXT4_EXT_MAY_ZEROOUT : 0;
3804                 split_flag |= (EXT4_EXT_MARK_UNWRIT2 | EXT4_EXT_DATA_VALID2);
3805         }
3806         flags |= EXT4_GET_BLOCKS_PRE_IO;
3807         return ext4_split_extent(handle, inode, ppath, map, split_flag, flags);
3808 }
3809
3810 static int ext4_convert_unwritten_extents_endio(handle_t *handle,
3811                                                 struct inode *inode,
3812                                                 struct ext4_map_blocks *map,
3813                                                 struct ext4_ext_path **ppath)
3814 {
3815         struct ext4_ext_path *path = *ppath;
3816         struct ext4_extent *ex;
3817         ext4_lblk_t ee_block;
3818         unsigned int ee_len;
3819         int depth;
3820         int err = 0;
3821
3822         depth = ext_depth(inode);
3823         ex = path[depth].p_ext;
3824         ee_block = le32_to_cpu(ex->ee_block);
3825         ee_len = ext4_ext_get_actual_len(ex);
3826
3827         ext_debug("ext4_convert_unwritten_extents_endio: inode %lu, logical"
3828                 "block %llu, max_blocks %u\n", inode->i_ino,
3829                   (unsigned long long)ee_block, ee_len);
3830
3831         /* If extent is larger than requested it is a clear sign that we still
3832          * have some extent state machine issues left. So extent_split is still
3833          * required.
3834          * TODO: Once all related issues will be fixed this situation should be
3835          * illegal.
3836          */
3837         if (ee_block != map->m_lblk || ee_len > map->m_len) {
3838 #ifdef CONFIG_EXT4_DEBUG
3839                 ext4_warning(inode->i_sb, "Inode (%ld) finished: extent logical block %llu,"
3840                              " len %u; IO logical block %llu, len %u",
3841                              inode->i_ino, (unsigned long long)ee_block, ee_len,
3842                              (unsigned long long)map->m_lblk, map->m_len);
3843 #endif
3844                 err = ext4_split_convert_extents(handle, inode, map, ppath,
3845                                                  EXT4_GET_BLOCKS_CONVERT);
3846                 if (err < 0)
3847                         return err;
3848                 path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3849                 if (IS_ERR(path))
3850                         return PTR_ERR(path);
3851                 depth = ext_depth(inode);
3852                 ex = path[depth].p_ext;
3853         }
3854
3855         err = ext4_ext_get_access(handle, inode, path + depth);
3856         if (err)
3857                 goto out;
3858         /* first mark the extent as initialized */
3859         ext4_ext_mark_initialized(ex);
3860
3861         /* note: ext4_ext_correct_indexes() isn't needed here because
3862          * borders are not changed
3863          */
3864         ext4_ext_try_to_merge(handle, inode, path, ex);
3865
3866         /* Mark modified extent as dirty */
3867         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3868 out:
3869         ext4_ext_show_leaf(inode, path);
3870         return err;
3871 }
3872
3873 /*
3874  * Handle EOFBLOCKS_FL flag, clearing it if necessary
3875  */
3876 static int check_eofblocks_fl(handle_t *handle, struct inode *inode,
3877                               ext4_lblk_t lblk,
3878                               struct ext4_ext_path *path,
3879                               unsigned int len)
3880 {
3881         int i, depth;
3882         struct ext4_extent_header *eh;
3883         struct ext4_extent *last_ex;
3884
3885         if (!ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS))
3886                 return 0;
3887
3888         depth = ext_depth(inode);
3889         eh = path[depth].p_hdr;
3890
3891         /*
3892          * We're going to remove EOFBLOCKS_FL entirely in future so we
3893          * do not care for this case anymore. Simply remove the flag
3894          * if there are no extents.
3895          */
3896         if (unlikely(!eh->eh_entries))
3897                 goto out;
3898         last_ex = EXT_LAST_EXTENT(eh);
3899         /*
3900          * We should clear the EOFBLOCKS_FL flag if we are writing the
3901          * last block in the last extent in the file.  We test this by
3902          * first checking to see if the caller to
3903          * ext4_ext_get_blocks() was interested in the last block (or
3904          * a block beyond the last block) in the current extent.  If
3905          * this turns out to be false, we can bail out from this
3906          * function immediately.
3907          */
3908         if (lblk + len < le32_to_cpu(last_ex->ee_block) +
3909             ext4_ext_get_actual_len(last_ex))
3910                 return 0;
3911         /*
3912          * If the caller does appear to be planning to write at or
3913          * beyond the end of the current extent, we then test to see
3914          * if the current extent is the last extent in the file, by
3915          * checking to make sure it was reached via the rightmost node
3916          * at each level of the tree.
3917          */
3918         for (i = depth-1; i >= 0; i--)
3919                 if (path[i].p_idx != EXT_LAST_INDEX(path[i].p_hdr))
3920                         return 0;
3921 out:
3922         ext4_clear_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
3923         return ext4_mark_inode_dirty(handle, inode);
3924 }
3925
3926 static int
3927 convert_initialized_extent(handle_t *handle, struct inode *inode,
3928                            struct ext4_map_blocks *map,
3929                            struct ext4_ext_path **ppath,
3930                            unsigned int allocated)
3931 {
3932         struct ext4_ext_path *path = *ppath;
3933         struct ext4_extent *ex;
3934         ext4_lblk_t ee_block;
3935         unsigned int ee_len;
3936         int depth;
3937         int err = 0;
3938
3939         /*
3940          * Make sure that the extent is no bigger than we support with
3941          * unwritten extent
3942          */
3943         if (map->m_len > EXT_UNWRITTEN_MAX_LEN)
3944                 map->m_len = EXT_UNWRITTEN_MAX_LEN / 2;
3945
3946         depth = ext_depth(inode);
3947         ex = path[depth].p_ext;
3948         ee_block = le32_to_cpu(ex->ee_block);
3949         ee_len = ext4_ext_get_actual_len(ex);
3950
3951         ext_debug("%s: inode %lu, logical"
3952                 "block %llu, max_blocks %u\n", __func__, inode->i_ino,
3953                   (unsigned long long)ee_block, ee_len);
3954
3955         if (ee_block != map->m_lblk || ee_len > map->m_len) {
3956                 err = ext4_split_convert_extents(handle, inode, map, ppath,
3957                                 EXT4_GET_BLOCKS_CONVERT_UNWRITTEN);
3958                 if (err < 0)
3959                         return err;
3960                 path = ext4_find_extent(inode, map->m_lblk, ppath, 0);
3961                 if (IS_ERR(path))
3962                         return PTR_ERR(path);
3963                 depth = ext_depth(inode);
3964                 ex = path[depth].p_ext;
3965                 if (!ex) {
3966                         EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
3967                                          (unsigned long) map->m_lblk);
3968                         return -EFSCORRUPTED;
3969                 }
3970         }
3971
3972         err = ext4_ext_get_access(handle, inode, path + depth);
3973         if (err)
3974                 return err;
3975         /* first mark the extent as unwritten */
3976         ext4_ext_mark_unwritten(ex);
3977
3978         /* note: ext4_ext_correct_indexes() isn't needed here because
3979          * borders are not changed
3980          */
3981         ext4_ext_try_to_merge(handle, inode, path, ex);
3982
3983         /* Mark modified extent as dirty */
3984         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3985         if (err)
3986                 return err;
3987         ext4_ext_show_leaf(inode, path);
3988
3989         ext4_update_inode_fsync_trans(handle, inode, 1);
3990         err = check_eofblocks_fl(handle, inode, map->m_lblk, path, map->m_len);
3991         if (err)
3992                 return err;
3993         map->m_flags |= EXT4_MAP_UNWRITTEN;
3994         if (allocated > map->m_len)
3995                 allocated = map->m_len;
3996         map->m_len = allocated;
3997         return allocated;
3998 }
3999
4000 static int
4001 ext4_ext_handle_unwritten_extents(handle_t *handle, struct inode *inode,
4002                         struct ext4_map_blocks *map,
4003                         struct ext4_ext_path **ppath, int flags,
4004                         unsigned int allocated, ext4_fsblk_t newblock)
4005 {
4006         struct ext4_ext_path *path = *ppath;
4007         int ret = 0;
4008         int err = 0;
4009
4010         ext_debug("ext4_ext_handle_unwritten_extents: inode %lu, logical "
4011                   "block %llu, max_blocks %u, flags %x, allocated %u\n",
4012                   inode->i_ino, (unsigned long long)map->m_lblk, map->m_len,
4013                   flags, allocated);
4014         ext4_ext_show_leaf(inode, path);
4015
4016         /*
4017          * When writing into unwritten space, we should not fail to
4018          * allocate metadata blocks for the new extent block if needed.
4019          */
4020         flags |= EXT4_GET_BLOCKS_METADATA_NOFAIL;
4021
4022         trace_ext4_ext_handle_unwritten_extents(inode, map, flags,
4023                                                     allocated, newblock);
4024
4025         /* get_block() before submit the IO, split the extent */
4026         if (flags & EXT4_GET_BLOCKS_PRE_IO) {
4027                 ret = ext4_split_convert_extents(handle, inode, map, ppath,
4028                                          flags | EXT4_GET_BLOCKS_CONVERT);
4029                 if (ret <= 0)
4030                         goto out;
4031                 map->m_flags |= EXT4_MAP_UNWRITTEN;
4032                 goto out;
4033         }
4034         /* IO end_io complete, convert the filled extent to written */
4035         if (flags & EXT4_GET_BLOCKS_CONVERT) {
4036                 if (flags & EXT4_GET_BLOCKS_ZERO) {
4037                         if (allocated > map->m_len)
4038                                 allocated = map->m_len;
4039                         err = ext4_issue_zeroout(inode, map->m_lblk, newblock,
4040                                                  allocated);
4041                         if (err < 0)
4042                                 goto out2;
4043                 }
4044                 ret = ext4_convert_unwritten_extents_endio(handle, inode, map,
4045                                                            ppath);
4046                 if (ret >= 0) {
4047                         ext4_update_inode_fsync_trans(handle, inode, 1);
4048                         err = check_eofblocks_fl(handle, inode, map->m_lblk,
4049                                                  path, map->m_len);
4050                 } else
4051                         err = ret;
4052                 map->m_flags |= EXT4_MAP_MAPPED;
4053                 map->m_pblk = newblock;
4054                 if (allocated > map->m_len)
4055                         allocated = map->m_len;
4056                 map->m_len = allocated;
4057                 goto out2;
4058         }
4059         /* buffered IO case */
4060         /*
4061          * repeat fallocate creation request
4062          * we already have an unwritten extent
4063          */
4064         if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT) {
4065                 map->m_flags |= EXT4_MAP_UNWRITTEN;
4066                 goto map_out;
4067         }
4068
4069         /* buffered READ or buffered write_begin() lookup */
4070         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
4071                 /*
4072                  * We have blocks reserved already.  We
4073                  * return allocated blocks so that delalloc
4074                  * won't do block reservation for us.  But
4075                  * the buffer head will be unmapped so that
4076                  * a read from the block returns 0s.
4077                  */
4078                 map->m_flags |= EXT4_MAP_UNWRITTEN;
4079                 goto out1;
4080         }
4081
4082         /* buffered write, writepage time, convert*/
4083         ret = ext4_ext_convert_to_initialized(handle, inode, map, ppath, flags);
4084         if (ret >= 0)
4085                 ext4_update_inode_fsync_trans(handle, inode, 1);
4086 out:
4087         if (ret <= 0) {
4088                 err = ret;
4089                 goto out2;
4090         } else
4091                 allocated = ret;
4092         map->m_flags |= EXT4_MAP_NEW;
4093         if (allocated > map->m_len)
4094                 allocated = map->m_len;
4095         map->m_len = allocated;
4096
4097 map_out:
4098         map->m_flags |= EXT4_MAP_MAPPED;
4099         if ((flags & EXT4_GET_BLOCKS_KEEP_SIZE) == 0) {
4100                 err = check_eofblocks_fl(handle, inode, map->m_lblk, path,
4101                                          map->m_len);
4102                 if (err < 0)
4103                         goto out2;
4104         }
4105 out1:
4106         if (allocated > map->m_len)
4107                 allocated = map->m_len;
4108         ext4_ext_show_leaf(inode, path);
4109         map->m_pblk = newblock;
4110         map->m_len = allocated;
4111 out2:
4112         return err ? err : allocated;
4113 }
4114
4115 /*
4116  * get_implied_cluster_alloc - check to see if the requested
4117  * allocation (in the map structure) overlaps with a cluster already
4118  * allocated in an extent.
4119  *      @sb     The filesystem superblock structure
4120  *      @map    The requested lblk->pblk mapping
4121  *      @ex     The extent structure which might contain an implied
4122  *                      cluster allocation
4123  *
4124  * This function is called by ext4_ext_map_blocks() after we failed to
4125  * find blocks that were already in the inode's extent tree.  Hence,
4126  * we know that the beginning of the requested region cannot overlap
4127  * the extent from the inode's extent tree.  There are three cases we
4128  * want to catch.  The first is this case:
4129  *
4130  *               |--- cluster # N--|
4131  *    |--- extent ---|  |---- requested region ---|
4132  *                      |==========|
4133  *
4134  * The second case that we need to test for is this one:
4135  *
4136  *   |--------- cluster # N ----------------|
4137  *         |--- requested region --|   |------- extent ----|
4138  *         |=======================|
4139  *
4140  * The third case is when the requested region lies between two extents
4141  * within the same cluster:
4142  *          |------------- cluster # N-------------|
4143  * |----- ex -----|                  |---- ex_right ----|
4144  *                  |------ requested region ------|
4145  *                  |================|
4146  *
4147  * In each of the above cases, we need to set the map->m_pblk and
4148  * map->m_len so it corresponds to the return the extent labelled as
4149  * "|====|" from cluster #N, since it is already in use for data in
4150  * cluster EXT4_B2C(sbi, map->m_lblk).  We will then return 1 to
4151  * signal to ext4_ext_map_blocks() that map->m_pblk should be treated
4152  * as a new "allocated" block region.  Otherwise, we will return 0 and
4153  * ext4_ext_map_blocks() will then allocate one or more new clusters
4154  * by calling ext4_mb_new_blocks().
4155  */
4156 static int get_implied_cluster_alloc(struct super_block *sb,
4157                                      struct ext4_map_blocks *map,
4158                                      struct ext4_extent *ex,
4159                                      struct ext4_ext_path *path)
4160 {
4161         struct ext4_sb_info *sbi = EXT4_SB(sb);
4162         ext4_lblk_t c_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4163         ext4_lblk_t ex_cluster_start, ex_cluster_end;
4164         ext4_lblk_t rr_cluster_start;
4165         ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
4166         ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
4167         unsigned short ee_len = ext4_ext_get_actual_len(ex);
4168
4169         /* The extent passed in that we are trying to match */
4170         ex_cluster_start = EXT4_B2C(sbi, ee_block);
4171         ex_cluster_end = EXT4_B2C(sbi, ee_block + ee_len - 1);
4172
4173         /* The requested region passed into ext4_map_blocks() */
4174         rr_cluster_start = EXT4_B2C(sbi, map->m_lblk);
4175
4176         if ((rr_cluster_start == ex_cluster_end) ||
4177             (rr_cluster_start == ex_cluster_start)) {
4178                 if (rr_cluster_start == ex_cluster_end)
4179                         ee_start += ee_len - 1;
4180                 map->m_pblk = EXT4_PBLK_CMASK(sbi, ee_start) + c_offset;
4181                 map->m_len = min(map->m_len,
4182                                  (unsigned) sbi->s_cluster_ratio - c_offset);
4183                 /*
4184                  * Check for and handle this case:
4185                  *
4186                  *   |--------- cluster # N-------------|
4187                  *                     |------- extent ----|
4188                  *         |--- requested region ---|
4189                  *         |===========|
4190                  */
4191
4192                 if (map->m_lblk < ee_block)
4193                         map->m_len = min(map->m_len, ee_block - map->m_lblk);
4194
4195                 /*
4196                  * Check for the case where there is already another allocated
4197                  * block to the right of 'ex' but before the end of the cluster.
4198                  *
4199                  *          |------------- cluster # N-------------|
4200                  * |----- ex -----|                  |---- ex_right ----|
4201                  *                  |------ requested region ------|
4202                  *                  |================|
4203                  */
4204                 if (map->m_lblk > ee_block) {
4205                         ext4_lblk_t next = ext4_ext_next_allocated_block(path);
4206                         map->m_len = min(map->m_len, next - map->m_lblk);
4207                 }
4208
4209                 trace_ext4_get_implied_cluster_alloc_exit(sb, map, 1);
4210                 return 1;
4211         }
4212
4213         trace_ext4_get_implied_cluster_alloc_exit(sb, map, 0);
4214         return 0;
4215 }
4216
4217
4218 /*
4219  * Block allocation/map/preallocation routine for extents based files
4220  *
4221  *
4222  * Need to be called with
4223  * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block
4224  * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
4225  *
4226  * return > 0, number of of blocks already mapped/allocated
4227  *          if create == 0 and these are pre-allocated blocks
4228  *              buffer head is unmapped
4229  *          otherwise blocks are mapped
4230  *
4231  * return = 0, if plain look up failed (blocks have not been allocated)
4232  *          buffer head is unmapped
4233  *
4234  * return < 0, error case.
4235  */
4236 int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
4237                         struct ext4_map_blocks *map, int flags)
4238 {
4239         struct ext4_ext_path *path = NULL;
4240         struct ext4_extent newex, *ex, *ex2;
4241         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4242         ext4_fsblk_t newblock = 0;
4243         int free_on_err = 0, err = 0, depth, ret;
4244         unsigned int allocated = 0, offset = 0;
4245         unsigned int allocated_clusters = 0;
4246         struct ext4_allocation_request ar;
4247         ext4_lblk_t cluster_offset;
4248         bool map_from_cluster = false;
4249
4250         ext_debug("blocks %u/%u requested for inode %lu\n",
4251                   map->m_lblk, map->m_len, inode->i_ino);
4252         trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
4253
4254         /* find extent for this block */
4255         path = ext4_find_extent(inode, map->m_lblk, NULL, 0);
4256         if (IS_ERR(path)) {
4257                 err = PTR_ERR(path);
4258                 path = NULL;
4259                 goto out2;
4260         }
4261
4262         depth = ext_depth(inode);
4263
4264         /*
4265          * consistent leaf must not be empty;
4266          * this situation is possible, though, _during_ tree modification;
4267          * this is why assert can't be put in ext4_find_extent()
4268          */
4269         if (unlikely(path[depth].p_ext == NULL && depth != 0)) {
4270                 EXT4_ERROR_INODE(inode, "bad extent address "
4271                                  "lblock: %lu, depth: %d pblock %lld",
4272                                  (unsigned long) map->m_lblk, depth,
4273                                  path[depth].p_block);
4274                 err = -EFSCORRUPTED;
4275                 goto out2;
4276         }
4277
4278         ex = path[depth].p_ext;
4279         if (ex) {
4280                 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
4281                 ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
4282                 unsigned short ee_len;
4283
4284
4285                 /*
4286                  * unwritten extents are treated as holes, except that
4287                  * we split out initialized portions during a write.
4288                  */
4289                 ee_len = ext4_ext_get_actual_len(ex);
4290
4291                 trace_ext4_ext_show_extent(inode, ee_block, ee_start, ee_len);
4292
4293                 /* if found extent covers block, simply return it */
4294                 if (in_range(map->m_lblk, ee_block, ee_len)) {
4295                         newblock = map->m_lblk - ee_block + ee_start;
4296                         /* number of remaining blocks in the extent */
4297                         allocated = ee_len - (map->m_lblk - ee_block);
4298                         ext_debug("%u fit into %u:%d -> %llu\n", map->m_lblk,
4299                                   ee_block, ee_len, newblock);
4300
4301                         /*
4302                          * If the extent is initialized check whether the
4303                          * caller wants to convert it to unwritten.
4304                          */
4305                         if ((!ext4_ext_is_unwritten(ex)) &&
4306                             (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN)) {
4307                                 allocated = convert_initialized_extent(
4308                                                 handle, inode, map, &path,
4309                                                 allocated);
4310                                 goto out2;
4311                         } else if (!ext4_ext_is_unwritten(ex))
4312                                 goto out;
4313
4314                         ret = ext4_ext_handle_unwritten_extents(
4315                                 handle, inode, map, &path, flags,
4316                                 allocated, newblock);
4317                         if (ret < 0)
4318                                 err = ret;
4319                         else
4320                                 allocated = ret;
4321                         goto out2;
4322                 }
4323         }
4324
4325         /*
4326          * requested block isn't allocated yet;
4327          * we couldn't try to create block if create flag is zero
4328          */
4329         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
4330                 ext4_lblk_t hole_start, hole_len;
4331
4332                 hole_start = map->m_lblk;
4333                 hole_len = ext4_ext_determine_hole(inode, path, &hole_start);
4334                 /*
4335                  * put just found gap into cache to speed up
4336                  * subsequent requests
4337                  */
4338                 ext4_ext_put_gap_in_cache(inode, hole_start, hole_len);
4339
4340                 /* Update hole_len to reflect hole size after map->m_lblk */
4341                 if (hole_start != map->m_lblk)
4342                         hole_len -= map->m_lblk - hole_start;
4343                 map->m_pblk = 0;
4344                 map->m_len = min_t(unsigned int, map->m_len, hole_len);
4345
4346                 goto out2;
4347         }
4348
4349         /*
4350          * Okay, we need to do block allocation.
4351          */
4352         newex.ee_block = cpu_to_le32(map->m_lblk);
4353         cluster_offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4354
4355         /*
4356          * If we are doing bigalloc, check to see if the extent returned
4357          * by ext4_find_extent() implies a cluster we can use.
4358          */
4359         if (cluster_offset && ex &&
4360             get_implied_cluster_alloc(inode->i_sb, map, ex, path)) {
4361                 ar.len = allocated = map->m_len;
4362                 newblock = map->m_pblk;
4363                 map_from_cluster = true;
4364                 goto got_allocated_blocks;
4365         }
4366
4367         /* find neighbour allocated blocks */
4368         ar.lleft = map->m_lblk;
4369         err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft);
4370         if (err)
4371                 goto out2;
4372         ar.lright = map->m_lblk;
4373         ex2 = NULL;
4374         err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright, &ex2);
4375         if (err)
4376                 goto out2;
4377
4378         /* Check if the extent after searching to the right implies a
4379          * cluster we can use. */
4380         if ((sbi->s_cluster_ratio > 1) && ex2 &&
4381             get_implied_cluster_alloc(inode->i_sb, map, ex2, path)) {
4382                 ar.len = allocated = map->m_len;
4383                 newblock = map->m_pblk;
4384                 map_from_cluster = true;
4385                 goto got_allocated_blocks;
4386         }
4387
4388         /*
4389          * See if request is beyond maximum number of blocks we can have in
4390          * a single extent. For an initialized extent this limit is
4391          * EXT_INIT_MAX_LEN and for an unwritten extent this limit is
4392          * EXT_UNWRITTEN_MAX_LEN.
4393          */
4394         if (map->m_len > EXT_INIT_MAX_LEN &&
4395             !(flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
4396                 map->m_len = EXT_INIT_MAX_LEN;
4397         else if (map->m_len > EXT_UNWRITTEN_MAX_LEN &&
4398                  (flags & EXT4_GET_BLOCKS_UNWRIT_EXT))
4399                 map->m_len = EXT_UNWRITTEN_MAX_LEN;
4400
4401         /* Check if we can really insert (m_lblk)::(m_lblk + m_len) extent */
4402         newex.ee_len = cpu_to_le16(map->m_len);
4403         err = ext4_ext_check_overlap(sbi, inode, &newex, path);
4404         if (err)
4405                 allocated = ext4_ext_get_actual_len(&newex);
4406         else
4407                 allocated = map->m_len;
4408
4409         /* allocate new block */
4410         ar.inode = inode;
4411         ar.goal = ext4_ext_find_goal(inode, path, map->m_lblk);
4412         ar.logical = map->m_lblk;
4413         /*
4414          * We calculate the offset from the beginning of the cluster
4415          * for the logical block number, since when we allocate a
4416          * physical cluster, the physical block should start at the
4417          * same offset from the beginning of the cluster.  This is
4418          * needed so that future calls to get_implied_cluster_alloc()
4419          * work correctly.
4420          */
4421         offset = EXT4_LBLK_COFF(sbi, map->m_lblk);
4422         ar.len = EXT4_NUM_B2C(sbi, offset+allocated);
4423         ar.goal -= offset;
4424         ar.logical -= offset;
4425         if (S_ISREG(inode->i_mode))
4426                 ar.flags = EXT4_MB_HINT_DATA;
4427         else
4428                 /* disable in-core preallocation for non-regular files */
4429                 ar.flags = 0;
4430         if (flags & EXT4_GET_BLOCKS_NO_NORMALIZE)
4431                 ar.flags |= EXT4_MB_HINT_NOPREALLOC;
4432         if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
4433                 ar.flags |= EXT4_MB_DELALLOC_RESERVED;
4434         if (flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
4435                 ar.flags |= EXT4_MB_USE_RESERVED;
4436         newblock = ext4_mb_new_blocks(handle, &ar, &err);
4437         if (!newblock)
4438                 goto out2;
4439         ext_debug("allocate new block: goal %llu, found %llu/%u\n",
4440                   ar.goal, newblock, allocated);
4441         free_on_err = 1;
4442         allocated_clusters = ar.len;
4443         ar.len = EXT4_C2B(sbi, ar.len) - offset;
4444         if (ar.len > allocated)
4445                 ar.len = allocated;
4446
4447 got_allocated_blocks:
4448         /* try to insert new extent into found leaf and return */
4449         ext4_ext_store_pblock(&newex, newblock + offset);
4450         newex.ee_len = cpu_to_le16(ar.len);
4451         /* Mark unwritten */
4452         if (flags & EXT4_GET_BLOCKS_UNWRIT_EXT){
4453                 ext4_ext_mark_unwritten(&newex);
4454                 map->m_flags |= EXT4_MAP_UNWRITTEN;
4455         }
4456
4457         err = 0;
4458         if ((flags & EXT4_GET_BLOCKS_KEEP_SIZE) == 0)
4459                 err = check_eofblocks_fl(handle, inode, map->m_lblk,
4460                                          path, ar.len);
4461         if (!err)
4462                 err = ext4_ext_insert_extent(handle, inode, &path,
4463                                              &newex, flags);
4464
4465         if (err && free_on_err) {
4466                 int fb_flags = flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE ?
4467                         EXT4_FREE_BLOCKS_NO_QUOT_UPDATE : 0;
4468                 /* free data blocks we just allocated */
4469                 /* not a good idea to call discard here directly,
4470                  * but otherwise we'd need to call it every free() */
4471                 ext4_discard_preallocations(inode);
4472                 ext4_free_blocks(handle, inode, NULL, newblock,
4473                                  EXT4_C2B(sbi, allocated_clusters), fb_flags);
4474                 goto out2;
4475         }
4476
4477         /* previous routine could use block we allocated */
4478         newblock = ext4_ext_pblock(&newex);
4479         allocated = ext4_ext_get_actual_len(&newex);
4480         if (allocated > map->m_len)
4481                 allocated = map->m_len;
4482         map->m_flags |= EXT4_MAP_NEW;
4483
4484         /*
4485          * Reduce the reserved cluster count to reflect successful deferred
4486          * allocation of delayed allocated clusters or direct allocation of
4487          * clusters discovered to be delayed allocated.  Once allocated, a
4488          * cluster is not included in the reserved count.
4489          */
4490         if (test_opt(inode->i_sb, DELALLOC) && !map_from_cluster) {
4491                 if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
4492                         /*
4493                          * When allocating delayed allocated clusters, simply
4494                          * reduce the reserved cluster count and claim quota
4495                          */
4496                         ext4_da_update_reserve_space(inode, allocated_clusters,
4497                                                         1);
4498                 } else {
4499                         ext4_lblk_t lblk, len;
4500                         unsigned int n;
4501
4502                         /*
4503                          * When allocating non-delayed allocated clusters
4504                          * (from fallocate, filemap, DIO, or clusters
4505                          * allocated when delalloc has been disabled by
4506                          * ext4_nonda_switch), reduce the reserved cluster
4507                          * count by the number of allocated clusters that
4508                          * have previously been delayed allocated.  Quota
4509                          * has been claimed by ext4_mb_new_blocks() above,
4510                          * so release the quota reservations made for any
4511                          * previously delayed allocated clusters.
4512                          */
4513                         lblk = EXT4_LBLK_CMASK(sbi, map->m_lblk);
4514                         len = allocated_clusters << sbi->s_cluster_bits;
4515                         n = ext4_es_delayed_clu(inode, lblk, len);
4516                         if (n > 0)
4517                                 ext4_da_update_reserve_space(inode, (int) n, 0);
4518                 }
4519         }
4520
4521         /*
4522          * Cache the extent and update transaction to commit on fdatasync only
4523          * when it is _not_ an unwritten extent.
4524          */
4525         if ((flags & EXT4_GET_BLOCKS_UNWRIT_EXT) == 0)
4526                 ext4_update_inode_fsync_trans(handle, inode, 1);
4527         else
4528                 ext4_update_inode_fsync_trans(handle, inode, 0);
4529 out:
4530         if (allocated > map->m_len)
4531                 allocated = map->m_len;
4532         ext4_ext_show_leaf(inode, path);
4533         map->m_flags |= EXT4_MAP_MAPPED;
4534         map->m_pblk = newblock;
4535         map->m_len = allocated;
4536 out2:
4537         ext4_ext_drop_refs(path);
4538         kfree(path);
4539
4540         trace_ext4_ext_map_blocks_exit(inode, flags, map,
4541                                        err ? err : allocated);
4542         return err ? err : allocated;
4543 }
4544
4545 int ext4_ext_truncate(handle_t *handle, struct inode *inode)
4546 {
4547         struct super_block *sb = inode->i_sb;
4548         ext4_lblk_t last_block;
4549         int err = 0;
4550
4551         /*
4552          * TODO: optimization is possible here.
4553          * Probably we need not scan at all,
4554          * because page truncation is enough.
4555          */
4556
4557         /* we have to know where to truncate from in crash case */
4558         EXT4_I(inode)->i_disksize = inode->i_size;
4559         err = ext4_mark_inode_dirty(handle, inode);
4560         if (err)
4561                 return err;
4562
4563         last_block = (inode->i_size + sb->s_blocksize - 1)
4564                         >> EXT4_BLOCK_SIZE_BITS(sb);
4565 retry:
4566         err = ext4_es_remove_extent(inode, last_block,
4567                                     EXT_MAX_BLOCKS - last_block);
4568         if (err == -ENOMEM) {
4569                 cond_resched();
4570                 congestion_wait(BLK_RW_ASYNC, HZ/50);
4571                 goto retry;
4572         }
4573         if (err)
4574                 return err;
4575         return ext4_ext_remove_space(inode, last_block, EXT_MAX_BLOCKS - 1);
4576 }
4577
4578 static int ext4_alloc_file_blocks(struct file *file, ext4_lblk_t offset,
4579                                   ext4_lblk_t len, loff_t new_size,
4580                                   int flags)
4581 {
4582         struct inode *inode = file_inode(file);
4583         handle_t *handle;
4584         int ret = 0;
4585         int ret2 = 0;
4586         int retries = 0;
4587         int depth = 0;
4588         struct ext4_map_blocks map;
4589         unsigned int credits;
4590         loff_t epos;
4591
4592         BUG_ON(!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS));
4593         map.m_lblk = offset;
4594         map.m_len = len;
4595         /*
4596          * Don't normalize the request if it can fit in one extent so
4597          * that it doesn't get unnecessarily split into multiple
4598          * extents.
4599          */
4600         if (len <= EXT_UNWRITTEN_MAX_LEN)
4601                 flags |= EXT4_GET_BLOCKS_NO_NORMALIZE;
4602
4603         /*
4604          * credits to insert 1 extent into extent tree
4605          */
4606         credits = ext4_chunk_trans_blocks(inode, len);
4607         depth = ext_depth(inode);
4608
4609 retry:
4610         while (ret >= 0 && len) {
4611                 /*
4612                  * Recalculate credits when extent tree depth changes.
4613                  */
4614                 if (depth != ext_depth(inode)) {
4615                         credits = ext4_chunk_trans_blocks(inode, len);
4616                         depth = ext_depth(inode);
4617                 }
4618
4619                 handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
4620                                             credits);
4621                 if (IS_ERR(handle)) {
4622                         ret = PTR_ERR(handle);
4623                         break;
4624                 }
4625                 ret = ext4_map_blocks(handle, inode, &map, flags);
4626                 if (ret <= 0) {
4627                         ext4_debug("inode #%lu: block %u: len %u: "
4628                                    "ext4_ext_map_blocks returned %d",
4629                                    inode->i_ino, map.m_lblk,
4630                                    map.m_len, ret);
4631                         ext4_mark_inode_dirty(handle, inode);
4632                         ret2 = ext4_journal_stop(handle);
4633                         break;
4634                 }
4635                 map.m_lblk += ret;
4636                 map.m_len = len = len - ret;
4637                 epos = (loff_t)map.m_lblk << inode->i_blkbits;
4638                 inode->i_ctime = current_time(inode);
4639                 if (new_size) {
4640                         if (epos > new_size)
4641                                 epos = new_size;
4642                         if (ext4_update_inode_size(inode, epos) & 0x1)
4643                                 inode->i_mtime = inode->i_ctime;
4644                 } else {
4645                         if (epos > inode->i_size)
4646                                 ext4_set_inode_flag(inode,
4647                                                     EXT4_INODE_EOFBLOCKS);
4648                 }
4649                 ext4_mark_inode_dirty(handle, inode);
4650                 ext4_update_inode_fsync_trans(handle, inode, 1);
4651                 ret2 = ext4_journal_stop(handle);
4652                 if (ret2)
4653                         break;
4654         }
4655         if (ret == -ENOSPC &&
4656                         ext4_should_retry_alloc(inode->i_sb, &retries)) {
4657                 ret = 0;
4658                 goto retry;
4659         }
4660
4661         return ret > 0 ? ret2 : ret;
4662 }
4663
4664 static int ext4_collapse_range(struct inode *inode, loff_t offset, loff_t len);
4665
4666 static int ext4_insert_range(struct inode *inode, loff_t offset, loff_t len);
4667
4668 static long ext4_zero_range(struct file *file, loff_t offset,
4669                             loff_t len, int mode)
4670 {
4671         struct inode *inode = file_inode(file);
4672         handle_t *handle = NULL;
4673         unsigned int max_blocks;
4674         loff_t new_size = 0;
4675         int ret = 0;
4676         int flags;
4677         int credits;
4678         int partial_begin, partial_end;
4679         loff_t start, end;
4680         ext4_lblk_t lblk;
4681         unsigned int blkbits = inode->i_blkbits;
4682
4683         trace_ext4_zero_range(inode, offset, len, mode);
4684
4685         /* Call ext4_force_commit to flush all data in case of data=journal. */
4686         if (ext4_should_journal_data(inode)) {
4687                 ret = ext4_force_commit(inode->i_sb);
4688                 if (ret)
4689                         return ret;
4690         }
4691
4692         /*
4693          * Round up offset. This is not fallocate, we neet to zero out
4694          * blocks, so convert interior block aligned part of the range to
4695          * unwritten and possibly manually zero out unaligned parts of the
4696          * range.
4697          */
4698         start = round_up(offset, 1 << blkbits);
4699         end = round_down((offset + len), 1 << blkbits);
4700
4701         if (start < offset || end > offset + len)
4702                 return -EINVAL;
4703         partial_begin = offset & ((1 << blkbits) - 1);
4704         partial_end = (offset + len) & ((1 << blkbits) - 1);
4705
4706         lblk = start >> blkbits;
4707         max_blocks = (end >> blkbits);
4708         if (max_blocks < lblk)
4709                 max_blocks = 0;
4710         else
4711                 max_blocks -= lblk;
4712
4713         inode_lock(inode);
4714
4715         /*
4716          * Indirect files do not support unwritten extnets
4717          */
4718         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
4719                 ret = -EOPNOTSUPP;
4720                 goto out_mutex;
4721         }
4722
4723         if (!(mode & FALLOC_FL_KEEP_SIZE) &&
4724             (offset + len > inode->i_size ||
4725              offset + len > EXT4_I(inode)->i_disksize)) {
4726                 new_size = offset + len;
4727                 ret = inode_newsize_ok(inode, new_size);
4728                 if (ret)
4729                         goto out_mutex;
4730         }
4731
4732         flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
4733         if (mode & FALLOC_FL_KEEP_SIZE)
4734                 flags |= EXT4_GET_BLOCKS_KEEP_SIZE;
4735
4736         /* Wait all existing dio workers, newcomers will block on i_mutex */
4737         inode_dio_wait(inode);
4738
4739         /* Preallocate the range including the unaligned edges */
4740         if (partial_begin || partial_end) {
4741                 ret = ext4_alloc_file_blocks(file,
4742                                 round_down(offset, 1 << blkbits) >> blkbits,
4743                                 (round_up((offset + len), 1 << blkbits) -
4744                                  round_down(offset, 1 << blkbits)) >> blkbits,
4745                                 new_size, flags);
4746                 if (ret)
4747                         goto out_mutex;
4748
4749         }
4750
4751         /* Zero range excluding the unaligned edges */
4752         if (max_blocks > 0) {
4753                 flags |= (EXT4_GET_BLOCKS_CONVERT_UNWRITTEN |
4754                           EXT4_EX_NOCACHE);
4755
4756                 /*
4757                  * Prevent page faults from reinstantiating pages we have
4758                  * released from page cache.
4759                  */
4760                 down_write(&EXT4_I(inode)->i_mmap_sem);
4761
4762                 ret = ext4_break_layouts(inode);
4763                 if (ret) {
4764                         up_write(&EXT4_I(inode)->i_mmap_sem);
4765                         goto out_mutex;
4766                 }
4767
4768                 ret = ext4_update_disksize_before_punch(inode, offset, len);
4769                 if (ret) {
4770                         up_write(&EXT4_I(inode)->i_mmap_sem);
4771                         goto out_mutex;
4772                 }
4773                 /* Now release the pages and zero block aligned part of pages */
4774                 truncate_pagecache_range(inode, start, end - 1);
4775                 inode->i_mtime = inode->i_ctime = current_time(inode);
4776
4777                 ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size,
4778                                              flags);
4779                 up_write(&EXT4_I(inode)->i_mmap_sem);
4780                 if (ret)
4781                         goto out_mutex;
4782         }
4783         if (!partial_begin && !partial_end)
4784                 goto out_mutex;
4785
4786         /*
4787          * In worst case we have to writeout two nonadjacent unwritten
4788          * blocks and update the inode
4789          */
4790         credits = (2 * ext4_ext_index_trans_blocks(inode, 2)) + 1;
4791         if (ext4_should_journal_data(inode))
4792                 credits += 2;
4793         handle = ext4_journal_start(inode, EXT4_HT_MISC, credits);
4794         if (IS_ERR(handle)) {
4795                 ret = PTR_ERR(handle);
4796                 ext4_std_error(inode->i_sb, ret);
4797                 goto out_mutex;
4798         }
4799
4800         inode->i_mtime = inode->i_ctime = current_time(inode);
4801         if (new_size) {
4802                 ext4_update_inode_size(inode, new_size);
4803         } else {
4804                 /*
4805                 * Mark that we allocate beyond EOF so the subsequent truncate
4806                 * can proceed even if the new size is the same as i_size.
4807                 */
4808                 if (offset + len > inode->i_size)
4809                         ext4_set_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
4810         }
4811         ext4_mark_inode_dirty(handle, inode);
4812
4813         /* Zero out partial block at the edges of the range */
4814         ret = ext4_zero_partial_blocks(handle, inode, offset, len);
4815         if (ret >= 0)
4816                 ext4_update_inode_fsync_trans(handle, inode, 1);
4817
4818         if (file->f_flags & O_SYNC)
4819                 ext4_handle_sync(handle);
4820
4821         ext4_journal_stop(handle);
4822 out_mutex:
4823         inode_unlock(inode);
4824         return ret;
4825 }
4826
4827 /*
4828  * preallocate space for a file. This implements ext4's fallocate file
4829  * operation, which gets called from sys_fallocate system call.
4830  * For block-mapped files, posix_fallocate should fall back to the method
4831  * of writing zeroes to the required new blocks (the same behavior which is
4832  * expected for file systems which do not support fallocate() system call).
4833  */
4834 long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
4835 {
4836         struct inode *inode = file_inode(file);
4837         loff_t new_size = 0;
4838         unsigned int max_blocks;
4839         int ret = 0;
4840         int flags;
4841         ext4_lblk_t lblk;
4842         unsigned int blkbits = inode->i_blkbits;
4843
4844         /*
4845          * Encrypted inodes can't handle collapse range or insert
4846          * range since we would need to re-encrypt blocks with a
4847          * different IV or XTS tweak (which are based on the logical
4848          * block number).
4849          */
4850         if (IS_ENCRYPTED(inode) &&
4851             (mode & (FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_INSERT_RANGE)))
4852                 return -EOPNOTSUPP;
4853
4854         /* Return error if mode is not supported */
4855         if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
4856                      FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE |
4857                      FALLOC_FL_INSERT_RANGE))
4858                 return -EOPNOTSUPP;
4859
4860         if (mode & FALLOC_FL_PUNCH_HOLE)
4861                 return ext4_punch_hole(inode, offset, len);
4862
4863         ret = ext4_convert_inline_data(inode);
4864         if (ret)
4865                 return ret;
4866
4867         if (mode & FALLOC_FL_COLLAPSE_RANGE)
4868                 return ext4_collapse_range(inode, offset, len);
4869
4870         if (mode & FALLOC_FL_INSERT_RANGE)
4871                 return ext4_insert_range(inode, offset, len);
4872
4873         if (mode & FALLOC_FL_ZERO_RANGE)
4874                 return ext4_zero_range(file, offset, len, mode);
4875
4876         trace_ext4_fallocate_enter(inode, offset, len, mode);
4877         lblk = offset >> blkbits;
4878
4879         max_blocks = EXT4_MAX_BLOCKS(len, offset, blkbits);
4880         flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
4881         if (mode & FALLOC_FL_KEEP_SIZE)
4882                 flags |= EXT4_GET_BLOCKS_KEEP_SIZE;
4883
4884         inode_lock(inode);
4885
4886         /*
4887          * We only support preallocation for extent-based files only
4888          */
4889         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
4890                 ret = -EOPNOTSUPP;
4891                 goto out;
4892         }
4893
4894         if (!(mode & FALLOC_FL_KEEP_SIZE) &&
4895             (offset + len > inode->i_size ||
4896              offset + len > EXT4_I(inode)->i_disksize)) {
4897                 new_size = offset + len;
4898                 ret = inode_newsize_ok(inode, new_size);
4899                 if (ret)
4900                         goto out;
4901         }
4902
4903         /* Wait all existing dio workers, newcomers will block on i_mutex */
4904         inode_dio_wait(inode);
4905
4906         ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size, flags);
4907         if (ret)
4908                 goto out;
4909
4910         if (file->f_flags & O_SYNC && EXT4_SB(inode->i_sb)->s_journal) {
4911                 ret = jbd2_complete_transaction(EXT4_SB(inode->i_sb)->s_journal,
4912                                                 EXT4_I(inode)->i_sync_tid);
4913         }
4914 out:
4915         inode_unlock(inode);
4916         trace_ext4_fallocate_exit(inode, offset, max_blocks, ret);
4917         return ret;
4918 }
4919
4920 /*
4921  * This function convert a range of blocks to written extents
4922  * The caller of this function will pass the start offset and the size.
4923  * all unwritten extents within this range will be converted to
4924  * written extents.
4925  *
4926  * This function is called from the direct IO end io call back
4927  * function, to convert the fallocated extents after IO is completed.
4928  * Returns 0 on success.
4929  */
4930 int ext4_convert_unwritten_extents(handle_t *handle, struct inode *inode,
4931                                    loff_t offset, ssize_t len)
4932 {
4933         unsigned int max_blocks;
4934         int ret = 0;
4935         int ret2 = 0;
4936         struct ext4_map_blocks map;
4937         unsigned int blkbits = inode->i_blkbits;
4938         unsigned int credits = 0;
4939
4940         map.m_lblk = offset >> blkbits;
4941         max_blocks = EXT4_MAX_BLOCKS(len, offset, blkbits);
4942
4943         if (!handle) {
4944                 /*
4945                  * credits to insert 1 extent into extent tree
4946                  */
4947                 credits = ext4_chunk_trans_blocks(inode, max_blocks);
4948         }
4949         while (ret >= 0 && ret < max_blocks) {
4950                 map.m_lblk += ret;
4951                 map.m_len = (max_blocks -= ret);
4952                 if (credits) {
4953                         handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
4954                                                     credits);
4955                         if (IS_ERR(handle)) {
4956                                 ret = PTR_ERR(handle);
4957                                 break;
4958                         }
4959                 }
4960                 ret = ext4_map_blocks(handle, inode, &map,
4961                                       EXT4_GET_BLOCKS_IO_CONVERT_EXT);
4962                 if (ret <= 0)
4963                         ext4_warning(inode->i_sb,
4964                                      "inode #%lu: block %u: len %u: "
4965                                      "ext4_ext_map_blocks returned %d",
4966                                      inode->i_ino, map.m_lblk,
4967                                      map.m_len, ret);
4968                 ext4_mark_inode_dirty(handle, inode);
4969                 if (credits)
4970                         ret2 = ext4_journal_stop(handle);
4971                 if (ret <= 0 || ret2)
4972                         break;
4973         }
4974         return ret > 0 ? ret2 : ret;
4975 }
4976
4977 int ext4_convert_unwritten_io_end_vec(handle_t *handle, ext4_io_end_t *io_end)
4978 {
4979         int ret, err = 0;
4980         struct ext4_io_end_vec *io_end_vec;
4981
4982         /*
4983          * This is somewhat ugly but the idea is clear: When transaction is
4984          * reserved, everything goes into it. Otherwise we rather start several
4985          * smaller transactions for conversion of each extent separately.
4986          */
4987         if (handle) {
4988                 handle = ext4_journal_start_reserved(handle,
4989                                                      EXT4_HT_EXT_CONVERT);
4990                 if (IS_ERR(handle))
4991                         return PTR_ERR(handle);
4992         }
4993
4994         list_for_each_entry(io_end_vec, &io_end->list_vec, list) {
4995                 ret = ext4_convert_unwritten_extents(handle, io_end->inode,
4996                                                      io_end_vec->offset,
4997                                                      io_end_vec->size);
4998                 if (ret)
4999                         break;
5000         }
5001
5002         if (handle)
5003                 err = ext4_journal_stop(handle);
5004
5005         return ret < 0 ? ret : err;
5006 }
5007
5008 /*
5009  * If newes is not existing extent (newes->ec_pblk equals zero) find
5010  * delayed extent at start of newes and update newes accordingly and
5011  * return start of the next delayed extent.
5012  *
5013  * If newes is existing extent (newes->ec_pblk is not equal zero)
5014  * return start of next delayed extent or EXT_MAX_BLOCKS if no delayed
5015  * extent found. Leave newes unmodified.
5016  */
5017 static int ext4_find_delayed_extent(struct inode *inode,
5018                                     struct extent_status *newes)
5019 {
5020         struct extent_status es;
5021         ext4_lblk_t block, next_del;
5022
5023         if (newes->es_pblk == 0) {
5024                 ext4_es_find_extent_range(inode, &ext4_es_is_delayed,
5025                                           newes->es_lblk,
5026                                           newes->es_lblk + newes->es_len - 1,
5027                                           &es);
5028
5029                 /*
5030                  * No extent in extent-tree contains block @newes->es_pblk,
5031                  * then the block may stay in 1)a hole or 2)delayed-extent.
5032                  */
5033                 if (es.es_len == 0)
5034                         /* A hole found. */
5035                         return 0;
5036
5037                 if (es.es_lblk > newes->es_lblk) {
5038                         /* A hole found. */
5039                         newes->es_len = min(es.es_lblk - newes->es_lblk,
5040                                             newes->es_len);
5041                         return 0;
5042                 }
5043
5044                 newes->es_len = es.es_lblk + es.es_len - newes->es_lblk;
5045         }
5046
5047         block = newes->es_lblk + newes->es_len;
5048         ext4_es_find_extent_range(inode, &ext4_es_is_delayed, block,
5049                                   EXT_MAX_BLOCKS, &es);
5050         if (es.es_len == 0)
5051                 next_del = EXT_MAX_BLOCKS;
5052         else
5053                 next_del = es.es_lblk;
5054
5055         return next_del;
5056 }
5057
5058 static int ext4_xattr_fiemap(struct inode *inode,
5059                                 struct fiemap_extent_info *fieinfo)
5060 {
5061         __u64 physical = 0;
5062         __u64 length;
5063         __u32 flags = FIEMAP_EXTENT_LAST;
5064         int blockbits = inode->i_sb->s_blocksize_bits;
5065         int error = 0;
5066
5067         /* in-inode? */
5068         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
5069                 struct ext4_iloc iloc;
5070                 int offset;     /* offset of xattr in inode */
5071
5072                 error = ext4_get_inode_loc(inode, &iloc);
5073                 if (error)
5074                         return error;
5075                 physical = (__u64)iloc.bh->b_blocknr << blockbits;
5076                 offset = EXT4_GOOD_OLD_INODE_SIZE +
5077                                 EXT4_I(inode)->i_extra_isize;
5078                 physical += offset;
5079                 length = EXT4_SB(inode->i_sb)->s_inode_size - offset;
5080                 flags |= FIEMAP_EXTENT_DATA_INLINE;
5081                 brelse(iloc.bh);
5082         } else { /* external block */
5083                 physical = (__u64)EXT4_I(inode)->i_file_acl << blockbits;
5084                 length = inode->i_sb->s_blocksize;
5085         }
5086
5087         if (physical)
5088                 error = fiemap_fill_next_extent(fieinfo, 0, physical,
5089                                                 length, flags);
5090         return (error < 0 ? error : 0);
5091 }
5092
5093 static int _ext4_fiemap(struct inode *inode,
5094                         struct fiemap_extent_info *fieinfo,
5095                         __u64 start, __u64 len,
5096                         int (*fill)(struct inode *, ext4_lblk_t,
5097                                     ext4_lblk_t,
5098                                     struct fiemap_extent_info *))
5099 {
5100         ext4_lblk_t start_blk;
5101         u32 ext4_fiemap_flags = FIEMAP_FLAG_SYNC|FIEMAP_FLAG_XATTR;
5102
5103         int error = 0;
5104
5105         if (ext4_has_inline_data(inode)) {
5106                 int has_inline = 1;
5107
5108                 error = ext4_inline_data_fiemap(inode, fieinfo, &has_inline,
5109                                                 start, len);
5110
5111                 if (has_inline)
5112                         return error;
5113         }
5114
5115         if (fieinfo->fi_flags & FIEMAP_FLAG_CACHE) {
5116                 error = ext4_ext_precache(inode);
5117                 if (error)
5118                         return error;
5119                 fieinfo->fi_flags &= ~FIEMAP_FLAG_CACHE;
5120         }
5121
5122         /* fallback to generic here if not in extents fmt */
5123         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) &&
5124             fill == ext4_fill_fiemap_extents)
5125                 return generic_block_fiemap(inode, fieinfo, start, len,
5126                         ext4_get_block);
5127
5128         if (fill == ext4_fill_es_cache_info)
5129                 ext4_fiemap_flags &= FIEMAP_FLAG_XATTR;
5130         if (fiemap_check_flags(fieinfo, ext4_fiemap_flags))
5131                 return -EBADR;
5132
5133         if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) {
5134                 error = ext4_xattr_fiemap(inode, fieinfo);
5135         } else {
5136                 ext4_lblk_t len_blks;
5137                 __u64 last_blk;
5138
5139                 start_blk = start >> inode->i_sb->s_blocksize_bits;
5140                 last_blk = (start + len - 1) >> inode->i_sb->s_blocksize_bits;
5141                 if (last_blk >= EXT_MAX_BLOCKS)
5142                         last_blk = EXT_MAX_BLOCKS-1;
5143                 len_blks = ((ext4_lblk_t) last_blk) - start_blk + 1;
5144
5145                 /*
5146                  * Walk the extent tree gathering extent information
5147                  * and pushing extents back to the user.
5148                  */
5149                 error = fill(inode, start_blk, len_blks, fieinfo);
5150         }
5151         return error;
5152 }
5153
5154 int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
5155                 __u64 start, __u64 len)
5156 {
5157         return _ext4_fiemap(inode, fieinfo, start, len,
5158                             ext4_fill_fiemap_extents);
5159 }
5160
5161 int ext4_get_es_cache(struct inode *inode, struct fiemap_extent_info *fieinfo,
5162                       __u64 start, __u64 len)
5163 {
5164         if (ext4_has_inline_data(inode)) {
5165                 int has_inline;
5166
5167                 down_read(&EXT4_I(inode)->xattr_sem);
5168                 has_inline = ext4_has_inline_data(inode);
5169                 up_read(&EXT4_I(inode)->xattr_sem);
5170                 if (has_inline)
5171                         return 0;
5172         }
5173
5174         return _ext4_fiemap(inode, fieinfo, start, len,
5175                             ext4_fill_es_cache_info);
5176 }
5177
5178
5179 /*
5180  * ext4_access_path:
5181  * Function to access the path buffer for marking it dirty.
5182  * It also checks if there are sufficient credits left in the journal handle
5183  * to update path.
5184  */
5185 static int
5186 ext4_access_path(handle_t *handle, struct inode *inode,
5187                 struct ext4_ext_path *path)
5188 {
5189         int credits, err;
5190
5191         if (!ext4_handle_valid(handle))
5192                 return 0;
5193
5194         /*
5195          * Check if need to extend journal credits
5196          * 3 for leaf, sb, and inode plus 2 (bmap and group
5197          * descriptor) for each block group; assume two block
5198          * groups
5199          */
5200         credits = ext4_writepage_trans_blocks(inode);
5201         err = ext4_datasem_ensure_credits(handle, inode, 7, credits, 0);
5202         if (err < 0)
5203                 return err;
5204
5205         err = ext4_ext_get_access(handle, inode, path);
5206         return err;
5207 }
5208
5209 /*
5210  * ext4_ext_shift_path_extents:
5211  * Shift the extents of a path structure lying between path[depth].p_ext
5212  * and EXT_LAST_EXTENT(path[depth].p_hdr), by @shift blocks. @SHIFT tells
5213  * if it is right shift or left shift operation.
5214  */
5215 static int
5216 ext4_ext_shift_path_extents(struct ext4_ext_path *path, ext4_lblk_t shift,
5217                             struct inode *inode, handle_t *handle,
5218                             enum SHIFT_DIRECTION SHIFT)
5219 {
5220         int depth, err = 0;
5221         struct ext4_extent *ex_start, *ex_last;
5222         bool update = false;
5223         depth = path->p_depth;
5224
5225         while (depth >= 0) {
5226                 if (depth == path->p_depth) {
5227                         ex_start = path[depth].p_ext;
5228                         if (!ex_start)
5229                                 return -EFSCORRUPTED;
5230
5231                         ex_last = EXT_LAST_EXTENT(path[depth].p_hdr);
5232
5233                         err = ext4_access_path(handle, inode, path + depth);
5234                         if (err)
5235                                 goto out;
5236
5237                         if (ex_start == EXT_FIRST_EXTENT(path[depth].p_hdr))
5238                                 update = true;
5239
5240                         while (ex_start <= ex_last) {
5241                                 if (SHIFT == SHIFT_LEFT) {
5242                                         le32_add_cpu(&ex_start->ee_block,
5243                                                 -shift);
5244                                         /* Try to merge to the left. */
5245                                         if ((ex_start >
5246                                             EXT_FIRST_EXTENT(path[depth].p_hdr))
5247                                             &&
5248                                             ext4_ext_try_to_merge_right(inode,
5249                                             path, ex_start - 1))
5250                                                 ex_last--;
5251                                         else
5252                                                 ex_start++;
5253                                 } else {
5254                                         le32_add_cpu(&ex_last->ee_block, shift);
5255                                         ext4_ext_try_to_merge_right(inode, path,
5256                                                 ex_last);
5257                                         ex_last--;
5258                                 }
5259                         }
5260                         err = ext4_ext_dirty(handle, inode, path + depth);
5261                         if (err)
5262                                 goto out;
5263
5264                         if (--depth < 0 || !update)
5265                                 break;
5266                 }
5267
5268                 /* Update index too */
5269                 err = ext4_access_path(handle, inode, path + depth);
5270                 if (err)
5271                         goto out;
5272
5273                 if (SHIFT == SHIFT_LEFT)
5274                         le32_add_cpu(&path[depth].p_idx->ei_block, -shift);
5275                 else
5276                         le32_add_cpu(&path[depth].p_idx->ei_block, shift);
5277                 err = ext4_ext_dirty(handle, inode, path + depth);
5278                 if (err)
5279                         goto out;
5280
5281                 /* we are done if current index is not a starting index */
5282                 if (path[depth].p_idx != EXT_FIRST_INDEX(path[depth].p_hdr))
5283                         break;
5284
5285                 depth--;
5286         }
5287
5288 out:
5289         return err;
5290 }
5291
5292 /*
5293  * ext4_ext_shift_extents:
5294  * All the extents which lies in the range from @start to the last allocated
5295  * block for the @inode are shifted either towards left or right (depending
5296  * upon @SHIFT) by @shift blocks.
5297  * On success, 0 is returned, error otherwise.
5298  */
5299 static int
5300 ext4_ext_shift_extents(struct inode *inode, handle_t *handle,
5301                        ext4_lblk_t start, ext4_lblk_t shift,
5302                        enum SHIFT_DIRECTION SHIFT)
5303 {
5304         struct ext4_ext_path *path;
5305         int ret = 0, depth;
5306         struct ext4_extent *extent;
5307         ext4_lblk_t stop, *iterator, ex_start, ex_end;
5308
5309         /* Let path point to the last extent */
5310         path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL,
5311                                 EXT4_EX_NOCACHE);
5312         if (IS_ERR(path))
5313                 return PTR_ERR(path);
5314
5315         depth = path->p_depth;
5316         extent = path[depth].p_ext;
5317         if (!extent)
5318                 goto out;
5319
5320         stop = le32_to_cpu(extent->ee_block);
5321
5322        /*
5323         * For left shifts, make sure the hole on the left is big enough to
5324         * accommodate the shift.  For right shifts, make sure the last extent
5325         * won't be shifted beyond EXT_MAX_BLOCKS.
5326         */
5327         if (SHIFT == SHIFT_LEFT) {
5328                 path = ext4_find_extent(inode, start - 1, &path,
5329                                         EXT4_EX_NOCACHE);
5330                 if (IS_ERR(path))
5331                         return PTR_ERR(path);
5332                 depth = path->p_depth;
5333                 extent =  path[depth].p_ext;
5334                 if (extent) {
5335                         ex_start = le32_to_cpu(extent->ee_block);
5336                         ex_end = le32_to_cpu(extent->ee_block) +
5337                                 ext4_ext_get_actual_len(extent);
5338                 } else {
5339                         ex_start = 0;
5340                         ex_end = 0;
5341                 }
5342
5343                 if ((start == ex_start && shift > ex_start) ||
5344                     (shift > start - ex_end)) {
5345                         ret = -EINVAL;
5346                         goto out;
5347                 }
5348         } else {
5349                 if (shift > EXT_MAX_BLOCKS -
5350                     (stop + ext4_ext_get_actual_len(extent))) {
5351                         ret = -EINVAL;
5352                         goto out;
5353                 }
5354         }
5355
5356         /*
5357          * In case of left shift, iterator points to start and it is increased
5358          * till we reach stop. In case of right shift, iterator points to stop
5359          * and it is decreased till we reach start.
5360          */
5361         if (SHIFT == SHIFT_LEFT)
5362                 iterator = &start;
5363         else
5364                 iterator = &stop;
5365
5366         /*
5367          * Its safe to start updating extents.  Start and stop are unsigned, so
5368          * in case of right shift if extent with 0 block is reached, iterator
5369          * becomes NULL to indicate the end of the loop.
5370          */
5371         while (iterator && start <= stop) {
5372                 path = ext4_find_extent(inode, *iterator, &path,
5373                                         EXT4_EX_NOCACHE);
5374                 if (IS_ERR(path))
5375                         return PTR_ERR(path);
5376                 depth = path->p_depth;
5377                 extent = path[depth].p_ext;
5378                 if (!extent) {
5379                         EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
5380                                          (unsigned long) *iterator);
5381                         return -EFSCORRUPTED;
5382                 }
5383                 if (SHIFT == SHIFT_LEFT && *iterator >
5384                     le32_to_cpu(extent->ee_block)) {
5385                         /* Hole, move to the next extent */
5386                         if (extent < EXT_LAST_EXTENT(path[depth].p_hdr)) {
5387                                 path[depth].p_ext++;
5388                         } else {
5389                                 *iterator = ext4_ext_next_allocated_block(path);
5390                                 continue;
5391                         }
5392                 }
5393
5394                 if (SHIFT == SHIFT_LEFT) {
5395                         extent = EXT_LAST_EXTENT(path[depth].p_hdr);
5396                         *iterator = le32_to_cpu(extent->ee_block) +
5397                                         ext4_ext_get_actual_len(extent);
5398                 } else {
5399                         extent = EXT_FIRST_EXTENT(path[depth].p_hdr);
5400                         if (le32_to_cpu(extent->ee_block) > 0)
5401                                 *iterator = le32_to_cpu(extent->ee_block) - 1;
5402                         else
5403                                 /* Beginning is reached, end of the loop */
5404                                 iterator = NULL;
5405                         /* Update path extent in case we need to stop */
5406                         while (le32_to_cpu(extent->ee_block) < start)
5407                                 extent++;
5408                         path[depth].p_ext = extent;
5409                 }
5410                 ret = ext4_ext_shift_path_extents(path, shift, inode,
5411                                 handle, SHIFT);
5412                 if (ret)
5413                         break;
5414         }
5415 out:
5416         ext4_ext_drop_refs(path);
5417         kfree(path);
5418         return ret;
5419 }
5420
5421 /*
5422  * ext4_collapse_range:
5423  * This implements the fallocate's collapse range functionality for ext4
5424  * Returns: 0 and non-zero on error.
5425  */
5426 static int ext4_collapse_range(struct inode *inode, loff_t offset, loff_t len)
5427 {
5428         struct super_block *sb = inode->i_sb;
5429         ext4_lblk_t punch_start, punch_stop;
5430         handle_t *handle;
5431         unsigned int credits;
5432         loff_t new_size, ioffset;
5433         int ret;
5434
5435         /*
5436          * We need to test this early because xfstests assumes that a
5437          * collapse range of (0, 1) will return EOPNOTSUPP if the file
5438          * system does not support collapse range.
5439          */
5440         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
5441                 return -EOPNOTSUPP;
5442
5443         /* Collapse range works only on fs cluster size aligned regions. */
5444         if (!IS_ALIGNED(offset | len, EXT4_CLUSTER_SIZE(sb)))
5445                 return -EINVAL;
5446
5447         trace_ext4_collapse_range(inode, offset, len);
5448
5449         punch_start = offset >> EXT4_BLOCK_SIZE_BITS(sb);
5450         punch_stop = (offset + len) >> EXT4_BLOCK_SIZE_BITS(sb);
5451
5452         /* Call ext4_force_commit to flush all data in case of data=journal. */
5453         if (ext4_should_journal_data(inode)) {
5454                 ret = ext4_force_commit(inode->i_sb);
5455                 if (ret)
5456                         return ret;
5457         }
5458
5459         inode_lock(inode);
5460         /*
5461          * There is no need to overlap collapse range with EOF, in which case
5462          * it is effectively a truncate operation
5463          */
5464         if (offset + len >= inode->i_size) {
5465                 ret = -EINVAL;
5466                 goto out_mutex;
5467         }
5468
5469         /* Currently just for extent based files */
5470         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
5471                 ret = -EOPNOTSUPP;
5472                 goto out_mutex;
5473         }
5474
5475         /* Wait for existing dio to complete */
5476         inode_dio_wait(inode);
5477
5478         /*
5479          * Prevent page faults from reinstantiating pages we have released from
5480          * page cache.
5481          */
5482         down_write(&EXT4_I(inode)->i_mmap_sem);
5483
5484         ret = ext4_break_layouts(inode);
5485         if (ret)
5486                 goto out_mmap;
5487
5488         /*
5489          * Need to round down offset to be aligned with page size boundary
5490          * for page size > block size.
5491          */
5492         ioffset = round_down(offset, PAGE_SIZE);
5493         /*
5494          * Write tail of the last page before removed range since it will get
5495          * removed from the page cache below.
5496          */
5497         ret = filemap_write_and_wait_range(inode->i_mapping, ioffset, offset);
5498         if (ret)
5499                 goto out_mmap;
5500         /*
5501          * Write data that will be shifted to preserve them when discarding
5502          * page cache below. We are also protected from pages becoming dirty
5503          * by i_mmap_sem.
5504          */
5505         ret = filemap_write_and_wait_range(inode->i_mapping, offset + len,
5506                                            LLONG_MAX);
5507         if (ret)
5508                 goto out_mmap;
5509         truncate_pagecache(inode, ioffset);
5510
5511         credits = ext4_writepage_trans_blocks(inode);
5512         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
5513         if (IS_ERR(handle)) {
5514                 ret = PTR_ERR(handle);
5515                 goto out_mmap;
5516         }
5517
5518         down_write(&EXT4_I(inode)->i_data_sem);
5519         ext4_discard_preallocations(inode);
5520
5521         ret = ext4_es_remove_extent(inode, punch_start,
5522                                     EXT_MAX_BLOCKS - punch_start);
5523         if (ret) {
5524                 up_write(&EXT4_I(inode)->i_data_sem);
5525                 goto out_stop;
5526         }
5527
5528         ret = ext4_ext_remove_space(inode, punch_start, punch_stop - 1);
5529         if (ret) {
5530                 up_write(&EXT4_I(inode)->i_data_sem);
5531                 goto out_stop;
5532         }
5533         ext4_discard_preallocations(inode);
5534
5535         ret = ext4_ext_shift_extents(inode, handle, punch_stop,
5536                                      punch_stop - punch_start, SHIFT_LEFT);
5537         if (ret) {
5538                 up_write(&EXT4_I(inode)->i_data_sem);
5539                 goto out_stop;
5540         }
5541
5542         new_size = inode->i_size - len;
5543         i_size_write(inode, new_size);
5544         EXT4_I(inode)->i_disksize = new_size;
5545
5546         up_write(&EXT4_I(inode)->i_data_sem);
5547         if (IS_SYNC(inode))
5548                 ext4_handle_sync(handle);
5549         inode->i_mtime = inode->i_ctime = current_time(inode);
5550         ext4_mark_inode_dirty(handle, inode);
5551         ext4_update_inode_fsync_trans(handle, inode, 1);
5552
5553 out_stop:
5554         ext4_journal_stop(handle);
5555 out_mmap:
5556         up_write(&EXT4_I(inode)->i_mmap_sem);
5557 out_mutex:
5558         inode_unlock(inode);
5559         return ret;
5560 }
5561
5562 /*
5563  * ext4_insert_range:
5564  * This function implements the FALLOC_FL_INSERT_RANGE flag of fallocate.
5565  * The data blocks starting from @offset to the EOF are shifted by @len
5566  * towards right to create a hole in the @inode. Inode size is increased
5567  * by len bytes.
5568  * Returns 0 on success, error otherwise.
5569  */
5570 static int ext4_insert_range(struct inode *inode, loff_t offset, loff_t len)
5571 {
5572         struct super_block *sb = inode->i_sb;
5573         handle_t *handle;
5574         struct ext4_ext_path *path;
5575         struct ext4_extent *extent;
5576         ext4_lblk_t offset_lblk, len_lblk, ee_start_lblk = 0;
5577         unsigned int credits, ee_len;
5578         int ret = 0, depth, split_flag = 0;
5579         loff_t ioffset;
5580
5581         /*
5582          * We need to test this early because xfstests assumes that an
5583          * insert range of (0, 1) will return EOPNOTSUPP if the file
5584          * system does not support insert range.
5585          */
5586         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
5587                 return -EOPNOTSUPP;
5588
5589         /* Insert range works only on fs cluster size aligned regions. */
5590         if (!IS_ALIGNED(offset | len, EXT4_CLUSTER_SIZE(sb)))
5591                 return -EINVAL;
5592
5593         trace_ext4_insert_range(inode, offset, len);
5594
5595         offset_lblk = offset >> EXT4_BLOCK_SIZE_BITS(sb);
5596         len_lblk = len >> EXT4_BLOCK_SIZE_BITS(sb);
5597
5598         /* Call ext4_force_commit to flush all data in case of data=journal */
5599         if (ext4_should_journal_data(inode)) {
5600                 ret = ext4_force_commit(inode->i_sb);
5601                 if (ret)
5602                         return ret;
5603         }
5604
5605         inode_lock(inode);
5606         /* Currently just for extent based files */
5607         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
5608                 ret = -EOPNOTSUPP;
5609                 goto out_mutex;
5610         }
5611
5612         /* Check whether the maximum file size would be exceeded */
5613         if (len > inode->i_sb->s_maxbytes - inode->i_size) {
5614                 ret = -EFBIG;
5615                 goto out_mutex;
5616         }
5617
5618         /* Offset must be less than i_size */
5619         if (offset >= inode->i_size) {
5620                 ret = -EINVAL;
5621                 goto out_mutex;
5622         }
5623
5624         /* Wait for existing dio to complete */
5625         inode_dio_wait(inode);
5626
5627         /*
5628          * Prevent page faults from reinstantiating pages we have released from
5629          * page cache.
5630          */
5631         down_write(&EXT4_I(inode)->i_mmap_sem);
5632
5633         ret = ext4_break_layouts(inode);
5634         if (ret)
5635                 goto out_mmap;
5636
5637         /*
5638          * Need to round down to align start offset to page size boundary
5639          * for page size > block size.
5640          */
5641         ioffset = round_down(offset, PAGE_SIZE);
5642         /* Write out all dirty pages */
5643         ret = filemap_write_and_wait_range(inode->i_mapping, ioffset,
5644                         LLONG_MAX);
5645         if (ret)
5646                 goto out_mmap;
5647         truncate_pagecache(inode, ioffset);
5648
5649         credits = ext4_writepage_trans_blocks(inode);
5650         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
5651         if (IS_ERR(handle)) {
5652                 ret = PTR_ERR(handle);
5653                 goto out_mmap;
5654         }
5655
5656         /* Expand file to avoid data loss if there is error while shifting */
5657         inode->i_size += len;
5658         EXT4_I(inode)->i_disksize += len;
5659         inode->i_mtime = inode->i_ctime = current_time(inode);
5660         ret = ext4_mark_inode_dirty(handle, inode);
5661         if (ret)
5662                 goto out_stop;
5663
5664         down_write(&EXT4_I(inode)->i_data_sem);
5665         ext4_discard_preallocations(inode);
5666
5667         path = ext4_find_extent(inode, offset_lblk, NULL, 0);
5668         if (IS_ERR(path)) {
5669                 up_write(&EXT4_I(inode)->i_data_sem);
5670                 goto out_stop;
5671         }
5672
5673         depth = ext_depth(inode);
5674         extent = path[depth].p_ext;
5675         if (extent) {
5676                 ee_start_lblk = le32_to_cpu(extent->ee_block);
5677                 ee_len = ext4_ext_get_actual_len(extent);
5678
5679                 /*
5680                  * If offset_lblk is not the starting block of extent, split
5681                  * the extent @offset_lblk
5682                  */
5683                 if ((offset_lblk > ee_start_lblk) &&
5684                                 (offset_lblk < (ee_start_lblk + ee_len))) {
5685                         if (ext4_ext_is_unwritten(extent))
5686                                 split_flag = EXT4_EXT_MARK_UNWRIT1 |
5687                                         EXT4_EXT_MARK_UNWRIT2;
5688                         ret = ext4_split_extent_at(handle, inode, &path,
5689                                         offset_lblk, split_flag,
5690                                         EXT4_EX_NOCACHE |
5691                                         EXT4_GET_BLOCKS_PRE_IO |
5692                                         EXT4_GET_BLOCKS_METADATA_NOFAIL);
5693                 }
5694
5695                 ext4_ext_drop_refs(path);
5696                 kfree(path);
5697                 if (ret < 0) {
5698                         up_write(&EXT4_I(inode)->i_data_sem);
5699                         goto out_stop;
5700                 }
5701         } else {
5702                 ext4_ext_drop_refs(path);
5703                 kfree(path);
5704         }
5705
5706         ret = ext4_es_remove_extent(inode, offset_lblk,
5707                         EXT_MAX_BLOCKS - offset_lblk);
5708         if (ret) {
5709                 up_write(&EXT4_I(inode)->i_data_sem);
5710                 goto out_stop;
5711         }
5712
5713         /*
5714          * if offset_lblk lies in a hole which is at start of file, use
5715          * ee_start_lblk to shift extents
5716          */
5717         ret = ext4_ext_shift_extents(inode, handle,
5718                 ee_start_lblk > offset_lblk ? ee_start_lblk : offset_lblk,
5719                 len_lblk, SHIFT_RIGHT);
5720
5721         up_write(&EXT4_I(inode)->i_data_sem);
5722         if (IS_SYNC(inode))
5723                 ext4_handle_sync(handle);
5724         if (ret >= 0)
5725                 ext4_update_inode_fsync_trans(handle, inode, 1);
5726
5727 out_stop:
5728         ext4_journal_stop(handle);
5729 out_mmap:
5730         up_write(&EXT4_I(inode)->i_mmap_sem);
5731 out_mutex:
5732         inode_unlock(inode);
5733         return ret;
5734 }
5735
5736 /**
5737  * ext4_swap_extents() - Swap extents between two inodes
5738  * @handle: handle for this transaction
5739  * @inode1:     First inode
5740  * @inode2:     Second inode
5741  * @lblk1:      Start block for first inode
5742  * @lblk2:      Start block for second inode
5743  * @count:      Number of blocks to swap
5744  * @unwritten: Mark second inode's extents as unwritten after swap
5745  * @erp:        Pointer to save error value
5746  *
5747  * This helper routine does exactly what is promise "swap extents". All other
5748  * stuff such as page-cache locking consistency, bh mapping consistency or
5749  * extent's data copying must be performed by caller.
5750  * Locking:
5751  *              i_mutex is held for both inodes
5752  *              i_data_sem is locked for write for both inodes
5753  * Assumptions:
5754  *              All pages from requested range are locked for both inodes
5755  */
5756 int
5757 ext4_swap_extents(handle_t *handle, struct inode *inode1,
5758                   struct inode *inode2, ext4_lblk_t lblk1, ext4_lblk_t lblk2,
5759                   ext4_lblk_t count, int unwritten, int *erp)
5760 {
5761         struct ext4_ext_path *path1 = NULL;
5762         struct ext4_ext_path *path2 = NULL;
5763         int replaced_count = 0;
5764
5765         BUG_ON(!rwsem_is_locked(&EXT4_I(inode1)->i_data_sem));
5766         BUG_ON(!rwsem_is_locked(&EXT4_I(inode2)->i_data_sem));
5767         BUG_ON(!inode_is_locked(inode1));
5768         BUG_ON(!inode_is_locked(inode2));
5769
5770         *erp = ext4_es_remove_extent(inode1, lblk1, count);
5771         if (unlikely(*erp))
5772                 return 0;
5773         *erp = ext4_es_remove_extent(inode2, lblk2, count);
5774         if (unlikely(*erp))
5775                 return 0;
5776
5777         while (count) {
5778                 struct ext4_extent *ex1, *ex2, tmp_ex;
5779                 ext4_lblk_t e1_blk, e2_blk;
5780                 int e1_len, e2_len, len;
5781                 int split = 0;
5782
5783                 path1 = ext4_find_extent(inode1, lblk1, NULL, EXT4_EX_NOCACHE);
5784                 if (IS_ERR(path1)) {
5785                         *erp = PTR_ERR(path1);
5786                         path1 = NULL;
5787                 finish:
5788                         count = 0;
5789                         goto repeat;
5790                 }
5791                 path2 = ext4_find_extent(inode2, lblk2, NULL, EXT4_EX_NOCACHE);
5792                 if (IS_ERR(path2)) {
5793                         *erp = PTR_ERR(path2);
5794                         path2 = NULL;
5795                         goto finish;
5796                 }
5797                 ex1 = path1[path1->p_depth].p_ext;
5798                 ex2 = path2[path2->p_depth].p_ext;
5799                 /* Do we have somthing to swap ? */
5800                 if (unlikely(!ex2 || !ex1))
5801                         goto finish;
5802
5803                 e1_blk = le32_to_cpu(ex1->ee_block);
5804                 e2_blk = le32_to_cpu(ex2->ee_block);
5805                 e1_len = ext4_ext_get_actual_len(ex1);
5806                 e2_len = ext4_ext_get_actual_len(ex2);
5807
5808                 /* Hole handling */
5809                 if (!in_range(lblk1, e1_blk, e1_len) ||
5810                     !in_range(lblk2, e2_blk, e2_len)) {
5811                         ext4_lblk_t next1, next2;
5812
5813                         /* if hole after extent, then go to next extent */
5814                         next1 = ext4_ext_next_allocated_block(path1);
5815                         next2 = ext4_ext_next_allocated_block(path2);
5816                         /* If hole before extent, then shift to that extent */
5817                         if (e1_blk > lblk1)
5818                                 next1 = e1_blk;
5819                         if (e2_blk > lblk2)
5820                                 next2 = e2_blk;
5821                         /* Do we have something to swap */
5822                         if (next1 == EXT_MAX_BLOCKS || next2 == EXT_MAX_BLOCKS)
5823                                 goto finish;
5824                         /* Move to the rightest boundary */
5825                         len = next1 - lblk1;
5826                         if (len < next2 - lblk2)
5827                                 len = next2 - lblk2;
5828                         if (len > count)
5829                                 len = count;
5830                         lblk1 += len;
5831                         lblk2 += len;
5832                         count -= len;
5833                         goto repeat;
5834                 }
5835
5836                 /* Prepare left boundary */
5837                 if (e1_blk < lblk1) {
5838                         split = 1;
5839                         *erp = ext4_force_split_extent_at(handle, inode1,
5840                                                 &path1, lblk1, 0);
5841                         if (unlikely(*erp))
5842                                 goto finish;
5843                 }
5844                 if (e2_blk < lblk2) {
5845                         split = 1;
5846                         *erp = ext4_force_split_extent_at(handle, inode2,
5847                                                 &path2,  lblk2, 0);
5848                         if (unlikely(*erp))
5849                                 goto finish;
5850                 }
5851                 /* ext4_split_extent_at() may result in leaf extent split,
5852                  * path must to be revalidated. */
5853                 if (split)
5854                         goto repeat;
5855
5856                 /* Prepare right boundary */
5857                 len = count;
5858                 if (len > e1_blk + e1_len - lblk1)
5859                         len = e1_blk + e1_len - lblk1;
5860                 if (len > e2_blk + e2_len - lblk2)
5861                         len = e2_blk + e2_len - lblk2;
5862
5863                 if (len != e1_len) {
5864                         split = 1;
5865                         *erp = ext4_force_split_extent_at(handle, inode1,
5866                                                 &path1, lblk1 + len, 0);
5867                         if (unlikely(*erp))
5868                                 goto finish;
5869                 }
5870                 if (len != e2_len) {
5871                         split = 1;
5872                         *erp = ext4_force_split_extent_at(handle, inode2,
5873                                                 &path2, lblk2 + len, 0);
5874                         if (*erp)
5875                                 goto finish;
5876                 }
5877                 /* ext4_split_extent_at() may result in leaf extent split,
5878                  * path must to be revalidated. */
5879                 if (split)
5880                         goto repeat;
5881
5882                 BUG_ON(e2_len != e1_len);
5883                 *erp = ext4_ext_get_access(handle, inode1, path1 + path1->p_depth);
5884                 if (unlikely(*erp))
5885                         goto finish;
5886                 *erp = ext4_ext_get_access(handle, inode2, path2 + path2->p_depth);
5887                 if (unlikely(*erp))
5888                         goto finish;
5889
5890                 /* Both extents are fully inside boundaries. Swap it now */
5891                 tmp_ex = *ex1;
5892                 ext4_ext_store_pblock(ex1, ext4_ext_pblock(ex2));
5893                 ext4_ext_store_pblock(ex2, ext4_ext_pblock(&tmp_ex));
5894                 ex1->ee_len = cpu_to_le16(e2_len);
5895                 ex2->ee_len = cpu_to_le16(e1_len);
5896                 if (unwritten)
5897                         ext4_ext_mark_unwritten(ex2);
5898                 if (ext4_ext_is_unwritten(&tmp_ex))
5899                         ext4_ext_mark_unwritten(ex1);
5900
5901                 ext4_ext_try_to_merge(handle, inode2, path2, ex2);
5902                 ext4_ext_try_to_merge(handle, inode1, path1, ex1);
5903                 *erp = ext4_ext_dirty(handle, inode2, path2 +
5904                                       path2->p_depth);
5905                 if (unlikely(*erp))
5906                         goto finish;
5907                 *erp = ext4_ext_dirty(handle, inode1, path1 +
5908                                       path1->p_depth);
5909                 /*
5910                  * Looks scarry ah..? second inode already points to new blocks,
5911                  * and it was successfully dirtied. But luckily error may happen
5912                  * only due to journal error, so full transaction will be
5913                  * aborted anyway.
5914                  */
5915                 if (unlikely(*erp))
5916                         goto finish;
5917                 lblk1 += len;
5918                 lblk2 += len;
5919                 replaced_count += len;
5920                 count -= len;
5921
5922         repeat:
5923                 ext4_ext_drop_refs(path1);
5924                 kfree(path1);
5925                 ext4_ext_drop_refs(path2);
5926                 kfree(path2);
5927                 path1 = path2 = NULL;
5928         }
5929         return replaced_count;
5930 }
5931
5932 /*
5933  * ext4_clu_mapped - determine whether any block in a logical cluster has
5934  *                   been mapped to a physical cluster
5935  *
5936  * @inode - file containing the logical cluster
5937  * @lclu - logical cluster of interest
5938  *
5939  * Returns 1 if any block in the logical cluster is mapped, signifying
5940  * that a physical cluster has been allocated for it.  Otherwise,
5941  * returns 0.  Can also return negative error codes.  Derived from
5942  * ext4_ext_map_blocks().
5943  */
5944 int ext4_clu_mapped(struct inode *inode, ext4_lblk_t lclu)
5945 {
5946         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
5947         struct ext4_ext_path *path;
5948         int depth, mapped = 0, err = 0;
5949         struct ext4_extent *extent;
5950         ext4_lblk_t first_lblk, first_lclu, last_lclu;
5951
5952         /* search for the extent closest to the first block in the cluster */
5953         path = ext4_find_extent(inode, EXT4_C2B(sbi, lclu), NULL, 0);
5954         if (IS_ERR(path)) {
5955                 err = PTR_ERR(path);
5956                 path = NULL;
5957                 goto out;
5958         }
5959
5960         depth = ext_depth(inode);
5961
5962         /*
5963          * A consistent leaf must not be empty.  This situation is possible,
5964          * though, _during_ tree modification, and it's why an assert can't
5965          * be put in ext4_find_extent().
5966          */
5967         if (unlikely(path[depth].p_ext == NULL && depth != 0)) {
5968                 EXT4_ERROR_INODE(inode,
5969                     "bad extent address - lblock: %lu, depth: %d, pblock: %lld",
5970                                  (unsigned long) EXT4_C2B(sbi, lclu),
5971                                  depth, path[depth].p_block);
5972                 err = -EFSCORRUPTED;
5973                 goto out;
5974         }
5975
5976         extent = path[depth].p_ext;
5977
5978         /* can't be mapped if the extent tree is empty */
5979         if (extent == NULL)
5980                 goto out;
5981
5982         first_lblk = le32_to_cpu(extent->ee_block);
5983         first_lclu = EXT4_B2C(sbi, first_lblk);
5984
5985         /*
5986          * Three possible outcomes at this point - found extent spanning
5987          * the target cluster, to the left of the target cluster, or to the
5988          * right of the target cluster.  The first two cases are handled here.
5989          * The last case indicates the target cluster is not mapped.
5990          */
5991         if (lclu >= first_lclu) {
5992                 last_lclu = EXT4_B2C(sbi, first_lblk +
5993                                      ext4_ext_get_actual_len(extent) - 1);
5994                 if (lclu <= last_lclu) {
5995                         mapped = 1;
5996                 } else {
5997                         first_lblk = ext4_ext_next_allocated_block(path);
5998                         first_lclu = EXT4_B2C(sbi, first_lblk);
5999                         if (lclu == first_lclu)
6000                                 mapped = 1;
6001                 }
6002         }
6003
6004 out:
6005         ext4_ext_drop_refs(path);
6006         kfree(path);
6007
6008         return err ? err : mapped;
6009 }