fs/btrfs/ioctl.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2007 Oracle.  All rights reserved.
   4  */
   5
   6 #include <linux/kernel.h>
   7 #include <linux/bio.h>
   8 #include <linux/file.h>
   9 #include <linux/fs.h>
  10 #include <linux/fsnotify.h>
  11 #include <linux/pagemap.h>
  12 #include <linux/highmem.h>
  13 #include <linux/time.h>
  14 #include <linux/string.h>
  15 #include <linux/backing-dev.h>
  16 #include <linux/mount.h>
  17 #include <linux/namei.h>
  18 #include <linux/writeback.h>
  19 #include <linux/compat.h>
  20 #include <linux/security.h>
  21 #include <linux/xattr.h>
  22 #include <linux/mm.h>
  23 #include <linux/slab.h>
  24 #include <linux/blkdev.h>
  25 #include <linux/uuid.h>
  26 #include <linux/btrfs.h>
  27 #include <linux/uaccess.h>
  28 #include <linux/iversion.h>
  29 #include "ctree.h"
  30 #include "disk-io.h"
  31 #include "transaction.h"
  32 #include "btrfs_inode.h"
  33 #include "print-tree.h"
  34 #include "volumes.h"
  35 #include "locking.h"
  36 #include "inode-map.h"
  37 #include "backref.h"
  38 #include "rcu-string.h"
  39 #include "send.h"
  40 #include "dev-replace.h"
  41 #include "props.h"
  42 #include "sysfs.h"
  43 #include "qgroup.h"
  44 #include "tree-log.h"
  45 #include "compression.h"
  46 #include "space-info.h"
  47 #include "delalloc-space.h"
  48 #include "block-group.h"
  49
  50 #ifdef CONFIG_64BIT
  51 /* If we have a 32-bit userspace and 64-bit kernel, then the UAPI
  52  * structures are incorrect, as the timespec structure from userspace
  53  * is 4 bytes too small. We define these alternatives here to teach
  54  * the kernel about the 32-bit struct packing.
  55  */
  56 struct btrfs_ioctl_timespec_32 {
  57         __u64 sec;
  58         __u32 nsec;
  59 } __attribute__ ((__packed__));
  60
  61 struct btrfs_ioctl_received_subvol_args_32 {
  62         char    uuid[BTRFS_UUID_SIZE];  /* in */
  63         __u64   stransid;               /* in */
  64         __u64   rtransid;               /* out */
  65         struct btrfs_ioctl_timespec_32 stime; /* in */
  66         struct btrfs_ioctl_timespec_32 rtime; /* out */
  67         __u64   flags;                  /* in */
  68         __u64   reserved[16];           /* in */
  69 } __attribute__ ((__packed__));
  70
  71 #define BTRFS_IOC_SET_RECEIVED_SUBVOL_32 _IOWR(BTRFS_IOCTL_MAGIC, 37, \
  72                                 struct btrfs_ioctl_received_subvol_args_32)
  73 #endif
  74
  75 #if defined(CONFIG_64BIT) && defined(CONFIG_COMPAT)
  76 struct btrfs_ioctl_send_args_32 {
  77         __s64 send_fd;                  /* in */
  78         __u64 clone_sources_count;      /* in */
  79         compat_uptr_t clone_sources;    /* in */
  80         __u64 parent_root;              /* in */
  81         __u64 flags;                    /* in */
  82         __u64 reserved[4];              /* in */
  83 } __attribute__ ((__packed__));
  84
  85 #define BTRFS_IOC_SEND_32 _IOW(BTRFS_IOCTL_MAGIC, 38, \
  86                                struct btrfs_ioctl_send_args_32)
  87 #endif
  88
  89 static int btrfs_clone(struct inode *src, struct inode *inode,
  90                        u64 off, u64 olen, u64 olen_aligned, u64 destoff,
  91                        int no_time_update);
  92
  93 /* Mask out flags that are inappropriate for the given type of inode. */
  94 static unsigned int btrfs_mask_fsflags_for_type(struct inode *inode,
  95                 unsigned int flags)
  96 {
  97         if (S_ISDIR(inode->i_mode))
  98                 return flags;
  99         else if (S_ISREG(inode->i_mode))
 100                 return flags & ~FS_DIRSYNC_FL;
 101         else
 102                 return flags & (FS_NODUMP_FL | FS_NOATIME_FL);
 103 }
 104
 105 /*
 106  * Export internal inode flags to the format expected by the FS_IOC_GETFLAGS
 107  * ioctl.
 108  */
 109 static unsigned int btrfs_inode_flags_to_fsflags(unsigned int flags)
 110 {
 111         unsigned int iflags = 0;
 112
 113         if (flags & BTRFS_INODE_SYNC)
 114                 iflags |= FS_SYNC_FL;
 115         if (flags & BTRFS_INODE_IMMUTABLE)
 116                 iflags |= FS_IMMUTABLE_FL;
 117         if (flags & BTRFS_INODE_APPEND)
 118                 iflags |= FS_APPEND_FL;
 119         if (flags & BTRFS_INODE_NODUMP)
 120                 iflags |= FS_NODUMP_FL;
 121         if (flags & BTRFS_INODE_NOATIME)
 122                 iflags |= FS_NOATIME_FL;
 123         if (flags & BTRFS_INODE_DIRSYNC)
 124                 iflags |= FS_DIRSYNC_FL;
 125         if (flags & BTRFS_INODE_NODATACOW)
 126                 iflags |= FS_NOCOW_FL;
 127
 128         if (flags & BTRFS_INODE_NOCOMPRESS)
 129                 iflags |= FS_NOCOMP_FL;
 130         else if (flags & BTRFS_INODE_COMPRESS)
 131                 iflags |= FS_COMPR_FL;
 132
 133         return iflags;
 134 }
 135
 136 /*
 137  * Update inode->i_flags based on the btrfs internal flags.
 138  */
 139 void btrfs_sync_inode_flags_to_i_flags(struct inode *inode)
 140 {
 141         struct btrfs_inode *binode = BTRFS_I(inode);
 142         unsigned int new_fl = 0;
 143
 144         if (binode->flags & BTRFS_INODE_SYNC)
 145                 new_fl |= S_SYNC;
 146         if (binode->flags & BTRFS_INODE_IMMUTABLE)
 147                 new_fl |= S_IMMUTABLE;
 148         if (binode->flags & BTRFS_INODE_APPEND)
 149                 new_fl |= S_APPEND;
 150         if (binode->flags & BTRFS_INODE_NOATIME)
 151                 new_fl |= S_NOATIME;
 152         if (binode->flags & BTRFS_INODE_DIRSYNC)
 153                 new_fl |= S_DIRSYNC;
 154
 155         set_mask_bits(&inode->i_flags,
 156                       S_SYNC | S_APPEND | S_IMMUTABLE | S_NOATIME | S_DIRSYNC,
 157                       new_fl);
 158 }
 159
 160 static int btrfs_ioctl_getflags(struct file *file, void __user *arg)
 161 {
 162         struct btrfs_inode *binode = BTRFS_I(file_inode(file));
 163         unsigned int flags = btrfs_inode_flags_to_fsflags(binode->flags);
 164
 165         if (copy_to_user(arg, &flags, sizeof(flags)))
 166                 return -EFAULT;
 167         return 0;
 168 }
 169
 170 /* Check if @flags are a supported and valid set of FS_*_FL flags */
 171 static int check_fsflags(unsigned int flags)
 172 {
 173         if (flags & ~(FS_IMMUTABLE_FL | FS_APPEND_FL | \
 174                       FS_NOATIME_FL | FS_NODUMP_FL | \
 175                       FS_SYNC_FL | FS_DIRSYNC_FL | \
 176                       FS_NOCOMP_FL | FS_COMPR_FL |
 177                       FS_NOCOW_FL))
 178                 return -EOPNOTSUPP;
 179
 180         if ((flags & FS_NOCOMP_FL) && (flags & FS_COMPR_FL))
 181                 return -EINVAL;
 182
 183         return 0;
 184 }
 185
 186 static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
 187 {
 188         struct inode *inode = file_inode(file);
 189         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 190         struct btrfs_inode *binode = BTRFS_I(inode);
 191         struct btrfs_root *root = binode->root;
 192         struct btrfs_trans_handle *trans;
 193         unsigned int fsflags, old_fsflags;
 194         int ret;
 195         const char *comp = NULL;
 196         u32 binode_flags = binode->flags;
 197
 198         if (!inode_owner_or_capable(inode))
 199                 return -EPERM;
 200
 201         if (btrfs_root_readonly(root))
 202                 return -EROFS;
 203
 204         if (copy_from_user(&fsflags, arg, sizeof(fsflags)))
 205                 return -EFAULT;
 206
 207         ret = check_fsflags(fsflags);
 208         if (ret)
 209                 return ret;
 210
 211         ret = mnt_want_write_file(file);
 212         if (ret)
 213                 return ret;
 214
 215         inode_lock(inode);
 216
 217         fsflags = btrfs_mask_fsflags_for_type(inode, fsflags);
 218         old_fsflags = btrfs_inode_flags_to_fsflags(binode->flags);
 219         ret = vfs_ioc_setflags_prepare(inode, old_fsflags, fsflags);
 220         if (ret)
 221                 goto out_unlock;
 222
 223         if (fsflags & FS_SYNC_FL)
 224                 binode_flags |= BTRFS_INODE_SYNC;
 225         else
 226                 binode_flags &= ~BTRFS_INODE_SYNC;
 227         if (fsflags & FS_IMMUTABLE_FL)
 228                 binode_flags |= BTRFS_INODE_IMMUTABLE;
 229         else
 230                 binode_flags &= ~BTRFS_INODE_IMMUTABLE;
 231         if (fsflags & FS_APPEND_FL)
 232                 binode_flags |= BTRFS_INODE_APPEND;
 233         else
 234                 binode_flags &= ~BTRFS_INODE_APPEND;
 235         if (fsflags & FS_NODUMP_FL)
 236                 binode_flags |= BTRFS_INODE_NODUMP;
 237         else
 238                 binode_flags &= ~BTRFS_INODE_NODUMP;
 239         if (fsflags & FS_NOATIME_FL)
 240                 binode_flags |= BTRFS_INODE_NOATIME;
 241         else
 242                 binode_flags &= ~BTRFS_INODE_NOATIME;
 243         if (fsflags & FS_DIRSYNC_FL)
 244                 binode_flags |= BTRFS_INODE_DIRSYNC;
 245         else
 246                 binode_flags &= ~BTRFS_INODE_DIRSYNC;
 247         if (fsflags & FS_NOCOW_FL) {
 248                 if (S_ISREG(inode->i_mode)) {
 249                         /*
 250                          * It's safe to turn csums off here, no extents exist.
 251                          * Otherwise we want the flag to reflect the real COW
 252                          * status of the file and will not set it.
 253                          */
 254                         if (inode->i_size == 0)
 255                                 binode_flags |= BTRFS_INODE_NODATACOW |
 256                                                 BTRFS_INODE_NODATASUM;
 257                 } else {
 258                         binode_flags |= BTRFS_INODE_NODATACOW;
 259                 }
 260         } else {
 261                 /*
 262                  * Revert back under same assumptions as above
 263                  */
 264                 if (S_ISREG(inode->i_mode)) {
 265                         if (inode->i_size == 0)
 266                                 binode_flags &= ~(BTRFS_INODE_NODATACOW |
 267                                                   BTRFS_INODE_NODATASUM);
 268                 } else {
 269                         binode_flags &= ~BTRFS_INODE_NODATACOW;
 270                 }
 271         }
 272
 273         /*
 274          * The COMPRESS flag can only be changed by users, while the NOCOMPRESS
 275          * flag may be changed automatically if compression code won't make
 276          * things smaller.
 277          */
 278         if (fsflags & FS_NOCOMP_FL) {
 279                 binode_flags &= ~BTRFS_INODE_COMPRESS;
 280                 binode_flags |= BTRFS_INODE_NOCOMPRESS;
 281         } else if (fsflags & FS_COMPR_FL) {
 282
 283                 if (IS_SWAPFILE(inode)) {
 284                         ret = -ETXTBSY;
 285                         goto out_unlock;
 286                 }
 287
 288                 binode_flags |= BTRFS_INODE_COMPRESS;
 289                 binode_flags &= ~BTRFS_INODE_NOCOMPRESS;
 290
 291                 comp = btrfs_compress_type2str(fs_info->compress_type);
 292                 if (!comp || comp[0] == 0)
 293                         comp = btrfs_compress_type2str(BTRFS_COMPRESS_ZLIB);
 294         } else {
 295                 binode_flags &= ~(BTRFS_INODE_COMPRESS | BTRFS_INODE_NOCOMPRESS);
 296         }
 297
 298         /*
 299          * 1 for inode item
 300          * 2 for properties
 301          */
 302         trans = btrfs_start_transaction(root, 3);
 303         if (IS_ERR(trans)) {
 304                 ret = PTR_ERR(trans);
 305                 goto out_unlock;
 306         }
 307
 308         if (comp) {
 309                 ret = btrfs_set_prop(trans, inode, "btrfs.compression", comp,
 310                                      strlen(comp), 0);
 311                 if (ret) {
 312                         btrfs_abort_transaction(trans, ret);
 313                         goto out_end_trans;
 314                 }
 315         } else {
 316                 ret = btrfs_set_prop(trans, inode, "btrfs.compression", NULL,
 317                                      0, 0);
 318                 if (ret && ret != -ENODATA) {
 319                         btrfs_abort_transaction(trans, ret);
 320                         goto out_end_trans;
 321                 }
 322         }
 323
 324         binode->flags = binode_flags;
 325         btrfs_sync_inode_flags_to_i_flags(inode);
 326         inode_inc_iversion(inode);
 327         inode->i_ctime = current_time(inode);
 328         ret = btrfs_update_inode(trans, root, inode);
 329
 330  out_end_trans:
 331         btrfs_end_transaction(trans);
 332  out_unlock:
 333         inode_unlock(inode);
 334         mnt_drop_write_file(file);
 335         return ret;
 336 }
 337
 338 /*
 339  * Translate btrfs internal inode flags to xflags as expected by the
 340  * FS_IOC_FSGETXATT ioctl. Filter only the supported ones, unknown flags are
 341  * silently dropped.
 342  */
 343 static unsigned int btrfs_inode_flags_to_xflags(unsigned int flags)
 344 {
 345         unsigned int xflags = 0;
 346
 347         if (flags & BTRFS_INODE_APPEND)
 348                 xflags |= FS_XFLAG_APPEND;
 349         if (flags & BTRFS_INODE_IMMUTABLE)
 350                 xflags |= FS_XFLAG_IMMUTABLE;
 351         if (flags & BTRFS_INODE_NOATIME)
 352                 xflags |= FS_XFLAG_NOATIME;
 353         if (flags & BTRFS_INODE_NODUMP)
 354                 xflags |= FS_XFLAG_NODUMP;
 355         if (flags & BTRFS_INODE_SYNC)
 356                 xflags |= FS_XFLAG_SYNC;
 357
 358         return xflags;
 359 }
 360
 361 /* Check if @flags are a supported and valid set of FS_XFLAGS_* flags */
 362 static int check_xflags(unsigned int flags)
 363 {
 364         if (flags & ~(FS_XFLAG_APPEND | FS_XFLAG_IMMUTABLE | FS_XFLAG_NOATIME |
 365                       FS_XFLAG_NODUMP | FS_XFLAG_SYNC))
 366                 return -EOPNOTSUPP;
 367         return 0;
 368 }
 369
 370 /*
 371  * Set the xflags from the internal inode flags. The remaining items of fsxattr
 372  * are zeroed.
 373  */
 374 static int btrfs_ioctl_fsgetxattr(struct file *file, void __user *arg)
 375 {
 376         struct btrfs_inode *binode = BTRFS_I(file_inode(file));
 377         struct fsxattr fa;
 378
 379         simple_fill_fsxattr(&fa, btrfs_inode_flags_to_xflags(binode->flags));
 380         if (copy_to_user(arg, &fa, sizeof(fa)))
 381                 return -EFAULT;
 382
 383         return 0;
 384 }
 385
 386 static int btrfs_ioctl_fssetxattr(struct file *file, void __user *arg)
 387 {
 388         struct inode *inode = file_inode(file);
 389         struct btrfs_inode *binode = BTRFS_I(inode);
 390         struct btrfs_root *root = binode->root;
 391         struct btrfs_trans_handle *trans;
 392         struct fsxattr fa, old_fa;
 393         unsigned old_flags;
 394         unsigned old_i_flags;
 395         int ret = 0;
 396
 397         if (!inode_owner_or_capable(inode))
 398                 return -EPERM;
 399
 400         if (btrfs_root_readonly(root))
 401                 return -EROFS;
 402
 403         if (copy_from_user(&fa, arg, sizeof(fa)))
 404                 return -EFAULT;
 405
 406         ret = check_xflags(fa.fsx_xflags);
 407         if (ret)
 408                 return ret;
 409
 410         if (fa.fsx_extsize != 0 || fa.fsx_projid != 0 || fa.fsx_cowextsize != 0)
 411                 return -EOPNOTSUPP;
 412
 413         ret = mnt_want_write_file(file);
 414         if (ret)
 415                 return ret;
 416
 417         inode_lock(inode);
 418
 419         old_flags = binode->flags;
 420         old_i_flags = inode->i_flags;
 421
 422         simple_fill_fsxattr(&old_fa,
 423                             btrfs_inode_flags_to_xflags(binode->flags));
 424         ret = vfs_ioc_fssetxattr_check(inode, &old_fa, &fa);
 425         if (ret)
 426                 goto out_unlock;
 427
 428         if (fa.fsx_xflags & FS_XFLAG_SYNC)
 429                 binode->flags |= BTRFS_INODE_SYNC;
 430         else
 431                 binode->flags &= ~BTRFS_INODE_SYNC;
 432         if (fa.fsx_xflags & FS_XFLAG_IMMUTABLE)
 433                 binode->flags |= BTRFS_INODE_IMMUTABLE;
 434         else
 435                 binode->flags &= ~BTRFS_INODE_IMMUTABLE;
 436         if (fa.fsx_xflags & FS_XFLAG_APPEND)
 437                 binode->flags |= BTRFS_INODE_APPEND;
 438         else
 439                 binode->flags &= ~BTRFS_INODE_APPEND;
 440         if (fa.fsx_xflags & FS_XFLAG_NODUMP)
 441                 binode->flags |= BTRFS_INODE_NODUMP;
 442         else
 443                 binode->flags &= ~BTRFS_INODE_NODUMP;
 444         if (fa.fsx_xflags & FS_XFLAG_NOATIME)
 445                 binode->flags |= BTRFS_INODE_NOATIME;
 446         else
 447                 binode->flags &= ~BTRFS_INODE_NOATIME;
 448
 449         /* 1 item for the inode */
 450         trans = btrfs_start_transaction(root, 1);
 451         if (IS_ERR(trans)) {
 452                 ret = PTR_ERR(trans);
 453                 goto out_unlock;
 454         }
 455
 456         btrfs_sync_inode_flags_to_i_flags(inode);
 457         inode_inc_iversion(inode);
 458         inode->i_ctime = current_time(inode);
 459         ret = btrfs_update_inode(trans, root, inode);
 460
 461         btrfs_end_transaction(trans);
 462
 463 out_unlock:
 464         if (ret) {
 465                 binode->flags = old_flags;
 466                 inode->i_flags = old_i_flags;
 467         }
 468
 469         inode_unlock(inode);
 470         mnt_drop_write_file(file);
 471
 472         return ret;
 473 }
 474
 475 static int btrfs_ioctl_getversion(struct file *file, int __user *arg)
 476 {
 477         struct inode *inode = file_inode(file);
 478
 479         return put_user(inode->i_generation, arg);
 480 }
 481
 482 static noinline int btrfs_ioctl_fitrim(struct file *file, void __user *arg)
 483 {
 484         struct inode *inode = file_inode(file);
 485         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 486         struct btrfs_device *device;
 487         struct request_queue *q;
 488         struct fstrim_range range;
 489         u64 minlen = ULLONG_MAX;
 490         u64 num_devices = 0;
 491         int ret;
 492
 493         if (!capable(CAP_SYS_ADMIN))
 494                 return -EPERM;
 495
 496         /*
 497          * If the fs is mounted with nologreplay, which requires it to be
 498          * mounted in RO mode as well, we can not allow discard on free space
 499          * inside block groups, because log trees refer to extents that are not
 500          * pinned in a block group's free space cache (pinning the extents is
 501          * precisely the first phase of replaying a log tree).
 502          */
 503         if (btrfs_test_opt(fs_info, NOLOGREPLAY))
 504                 return -EROFS;
 505
 506         rcu_read_lock();
 507         list_for_each_entry_rcu(device, &fs_info->fs_devices->devices,
 508                                 dev_list) {
 509                 if (!device->bdev)
 510                         continue;
 511                 q = bdev_get_queue(device->bdev);
 512                 if (blk_queue_discard(q)) {
 513                         num_devices++;
 514                         minlen = min_t(u64, q->limits.discard_granularity,
 515                                      minlen);
 516                 }
 517         }
 518         rcu_read_unlock();
 519
 520         if (!num_devices)
 521                 return -EOPNOTSUPP;
 522         if (copy_from_user(&range, arg, sizeof(range)))
 523                 return -EFAULT;
 524
 525         /*
 526          * NOTE: Don't truncate the range using super->total_bytes.  Bytenr of
 527          * block group is in the logical address space, which can be any
 528          * sectorsize aligned bytenr in  the range [0, U64_MAX].
 529          */
 530         if (range.len < fs_info->sb->s_blocksize)
 531                 return -EINVAL;
 532
 533         range.minlen = max(range.minlen, minlen);
 534         ret = btrfs_trim_fs(fs_info, &range);
 535         if (ret < 0)
 536                 return ret;
 537
 538         if (copy_to_user(arg, &range, sizeof(range)))
 539                 return -EFAULT;
 540
 541         return 0;
 542 }
 543
 544 int btrfs_is_empty_uuid(u8 *uuid)
 545 {
 546         int i;
 547
 548         for (i = 0; i < BTRFS_UUID_SIZE; i++) {
 549                 if (uuid[i])
 550                         return 0;
 551         }
 552         return 1;
 553 }
 554
 555 static noinline int create_subvol(struct inode *dir,
 556                                   struct dentry *dentry,
 557                                   const char *name, int namelen,
 558                                   u64 *async_transid,
 559                                   struct btrfs_qgroup_inherit *inherit)
 560 {
 561         struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
 562         struct btrfs_trans_handle *trans;
 563         struct btrfs_key key;
 564         struct btrfs_root_item *root_item;
 565         struct btrfs_inode_item *inode_item;
 566         struct extent_buffer *leaf;
 567         struct btrfs_root *root = BTRFS_I(dir)->root;
 568         struct btrfs_root *new_root;
 569         struct btrfs_block_rsv block_rsv;
 570         struct timespec64 cur_time = current_time(dir);
 571         struct inode *inode;
 572         int ret;
 573         int err;
 574         u64 objectid;
 575         u64 new_dirid = BTRFS_FIRST_FREE_OBJECTID;
 576         u64 index = 0;
 577         uuid_le new_uuid;
 578
 579         root_item = kzalloc(sizeof(*root_item), GFP_KERNEL);
 580         if (!root_item)
 581                 return -ENOMEM;
 582
 583         ret = btrfs_find_free_objectid(fs_info->tree_root, &objectid);
 584         if (ret)
 585                 goto fail_free;
 586
 587         /*
 588          * Don't create subvolume whose level is not zero. Or qgroup will be
 589          * screwed up since it assumes subvolume qgroup's level to be 0.
 590          */
 591         if (btrfs_qgroup_level(objectid)) {
 592                 ret = -ENOSPC;
 593                 goto fail_free;
 594         }
 595
 596         btrfs_init_block_rsv(&block_rsv, BTRFS_BLOCK_RSV_TEMP);
 597         /*
 598          * The same as the snapshot creation, please see the comment
 599          * of create_snapshot().
 600          */
 601         ret = btrfs_subvolume_reserve_metadata(root, &block_rsv, 8, false);
 602         if (ret)
 603                 goto fail_free;
 604
 605         trans = btrfs_start_transaction(root, 0);
 606         if (IS_ERR(trans)) {
 607                 ret = PTR_ERR(trans);
 608                 btrfs_subvolume_release_metadata(fs_info, &block_rsv);
 609                 goto fail_free;
 610         }
 611         trans->block_rsv = &block_rsv;
 612         trans->bytes_reserved = block_rsv.size;
 613
 614         ret = btrfs_qgroup_inherit(trans, 0, objectid, inherit);
 615         if (ret)
 616                 goto fail;
 617
 618         leaf = btrfs_alloc_tree_block(trans, root, 0, objectid, NULL, 0, 0, 0);
 619         if (IS_ERR(leaf)) {
 620                 ret = PTR_ERR(leaf);
 621                 goto fail;
 622         }
 623
 624         btrfs_mark_buffer_dirty(leaf);
 625
 626         inode_item = &root_item->inode;
 627         btrfs_set_stack_inode_generation(inode_item, 1);
 628         btrfs_set_stack_inode_size(inode_item, 3);
 629         btrfs_set_stack_inode_nlink(inode_item, 1);
 630         btrfs_set_stack_inode_nbytes(inode_item,
 631                                      fs_info->nodesize);
 632         btrfs_set_stack_inode_mode(inode_item, S_IFDIR | 0755);
 633
 634         btrfs_set_root_flags(root_item, 0);
 635         btrfs_set_root_limit(root_item, 0);
 636         btrfs_set_stack_inode_flags(inode_item, BTRFS_INODE_ROOT_ITEM_INIT);
 637
 638         btrfs_set_root_bytenr(root_item, leaf->start);
 639         btrfs_set_root_generation(root_item, trans->transid);
 640         btrfs_set_root_level(root_item, 0);
 641         btrfs_set_root_refs(root_item, 1);
 642         btrfs_set_root_used(root_item, leaf->len);
 643         btrfs_set_root_last_snapshot(root_item, 0);
 644
 645         btrfs_set_root_generation_v2(root_item,
 646                         btrfs_root_generation(root_item));
 647         uuid_le_gen(&new_uuid);
 648         memcpy(root_item->uuid, new_uuid.b, BTRFS_UUID_SIZE);
 649         btrfs_set_stack_timespec_sec(&root_item->otime, cur_time.tv_sec);
 650         btrfs_set_stack_timespec_nsec(&root_item->otime, cur_time.tv_nsec);
 651         root_item->ctime = root_item->otime;
 652         btrfs_set_root_ctransid(root_item, trans->transid);
 653         btrfs_set_root_otransid(root_item, trans->transid);
 654
 655         btrfs_tree_unlock(leaf);
 656         free_extent_buffer(leaf);
 657         leaf = NULL;
 658
 659         btrfs_set_root_dirid(root_item, new_dirid);
 660
 661         key.objectid = objectid;
 662         key.offset = 0;
 663         key.type = BTRFS_ROOT_ITEM_KEY;
 664         ret = btrfs_insert_root(trans, fs_info->tree_root, &key,
 665                                 root_item);
 666         if (ret)
 667                 goto fail;
 668
 669         key.offset = (u64)-1;
 670         new_root = btrfs_read_fs_root_no_name(fs_info, &key);
 671         if (IS_ERR(new_root)) {
 672                 ret = PTR_ERR(new_root);
 673                 btrfs_abort_transaction(trans, ret);
 674                 goto fail;
 675         }
 676
 677         btrfs_record_root_in_trans(trans, new_root);
 678
 679         ret = btrfs_create_subvol_root(trans, new_root, root, new_dirid);
 680         if (ret) {
 681                 /* We potentially lose an unused inode item here */
 682                 btrfs_abort_transaction(trans, ret);
 683                 goto fail;
 684         }
 685
 686         mutex_lock(&new_root->objectid_mutex);
 687         new_root->highest_objectid = new_dirid;
 688         mutex_unlock(&new_root->objectid_mutex);
 689
 690         /*
 691          * insert the directory item
 692          */
 693         ret = btrfs_set_inode_index(BTRFS_I(dir), &index);
 694         if (ret) {
 695                 btrfs_abort_transaction(trans, ret);
 696                 goto fail;
 697         }
 698
 699         ret = btrfs_insert_dir_item(trans, name, namelen, BTRFS_I(dir), &key,
 700                                     BTRFS_FT_DIR, index);
 701         if (ret) {
 702                 btrfs_abort_transaction(trans, ret);
 703                 goto fail;
 704         }
 705
 706         btrfs_i_size_write(BTRFS_I(dir), dir->i_size + namelen * 2);
 707         ret = btrfs_update_inode(trans, root, dir);
 708         BUG_ON(ret);
 709
 710         ret = btrfs_add_root_ref(trans, objectid, root->root_key.objectid,
 711                                  btrfs_ino(BTRFS_I(dir)), index, name, namelen);
 712         BUG_ON(ret);
 713
 714         ret = btrfs_uuid_tree_add(trans, root_item->uuid,
 715                                   BTRFS_UUID_KEY_SUBVOL, objectid);
 716         if (ret)
 717                 btrfs_abort_transaction(trans, ret);
 718
 719 fail:
 720         kfree(root_item);
 721         trans->block_rsv = NULL;
 722         trans->bytes_reserved = 0;
 723         btrfs_subvolume_release_metadata(fs_info, &block_rsv);
 724
 725         if (async_transid) {
 726                 *async_transid = trans->transid;
 727                 err = btrfs_commit_transaction_async(trans, 1);
 728                 if (err)
 729                         err = btrfs_commit_transaction(trans);
 730         } else {
 731                 err = btrfs_commit_transaction(trans);
 732         }
 733         if (err && !ret)
 734                 ret = err;
 735
 736         if (!ret) {
 737                 inode = btrfs_lookup_dentry(dir, dentry);
 738                 if (IS_ERR(inode))
 739                         return PTR_ERR(inode);
 740                 d_instantiate(dentry, inode);
 741         }
 742         return ret;
 743
 744 fail_free:
 745         kfree(root_item);
 746         return ret;
 747 }
 748
 749 static int create_snapshot(struct btrfs_root *root, struct inode *dir,
 750                            struct dentry *dentry,
 751                            u64 *async_transid, bool readonly,
 752                            struct btrfs_qgroup_inherit *inherit)
 753 {
 754         struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
 755         struct inode *inode;
 756         struct btrfs_pending_snapshot *pending_snapshot;
 757         struct btrfs_trans_handle *trans;
 758         int ret;
 759         bool snapshot_force_cow = false;
 760
 761         if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
 762                 return -EINVAL;
 763
 764         if (atomic_read(&root->nr_swapfiles)) {
 765                 btrfs_warn(fs_info,
 766                            "cannot snapshot subvolume with active swapfile");
 767                 return -ETXTBSY;
 768         }
 769
 770         pending_snapshot = kzalloc(sizeof(*pending_snapshot), GFP_KERNEL);
 771         if (!pending_snapshot)
 772                 return -ENOMEM;
 773
 774         pending_snapshot->root_item = kzalloc(sizeof(struct btrfs_root_item),
 775                         GFP_KERNEL);
 776         pending_snapshot->path = btrfs_alloc_path();
 777         if (!pending_snapshot->root_item || !pending_snapshot->path) {
 778                 ret = -ENOMEM;
 779                 goto free_pending;
 780         }
 781
 782         /*
 783          * Force new buffered writes to reserve space even when NOCOW is
 784          * possible. This is to avoid later writeback (running dealloc) to
 785          * fallback to COW mode and unexpectedly fail with ENOSPC.
 786          */
 787         atomic_inc(&root->will_be_snapshotted);
 788         smp_mb__after_atomic();
 789         /* wait for no snapshot writes */
 790         wait_event(root->subv_writers->wait,
 791                    percpu_counter_sum(&root->subv_writers->counter) == 0);
 792
 793         ret = btrfs_start_delalloc_snapshot(root);
 794         if (ret)
 795                 goto dec_and_free;
 796
 797         /*
 798          * All previous writes have started writeback in NOCOW mode, so now
 799          * we force future writes to fallback to COW mode during snapshot
 800          * creation.
 801          */
 802         atomic_inc(&root->snapshot_force_cow);
 803         snapshot_force_cow = true;
 804
 805         btrfs_wait_ordered_extents(root, U64_MAX, 0, (u64)-1);
 806
 807         btrfs_init_block_rsv(&pending_snapshot->block_rsv,
 808                              BTRFS_BLOCK_RSV_TEMP);
 809         /*
 810          * 1 - parent dir inode
 811          * 2 - dir entries
 812          * 1 - root item
 813          * 2 - root ref/backref
 814          * 1 - root of snapshot
 815          * 1 - UUID item
 816          */
 817         ret = btrfs_subvolume_reserve_metadata(BTRFS_I(dir)->root,
 818                                         &pending_snapshot->block_rsv, 8,
 819                                         false);
 820         if (ret)
 821                 goto dec_and_free;
 822
 823         pending_snapshot->dentry = dentry;
 824         pending_snapshot->root = root;
 825         pending_snapshot->readonly = readonly;
 826         pending_snapshot->dir = dir;
 827         pending_snapshot->inherit = inherit;
 828
 829         trans = btrfs_start_transaction(root, 0);
 830         if (IS_ERR(trans)) {
 831                 ret = PTR_ERR(trans);
 832                 goto fail;
 833         }
 834
 835         spin_lock(&fs_info->trans_lock);
 836         list_add(&pending_snapshot->list,
 837                  &trans->transaction->pending_snapshots);
 838         spin_unlock(&fs_info->trans_lock);
 839         if (async_transid) {
 840                 *async_transid = trans->transid;
 841                 ret = btrfs_commit_transaction_async(trans, 1);
 842                 if (ret)
 843                         ret = btrfs_commit_transaction(trans);
 844         } else {
 845                 ret = btrfs_commit_transaction(trans);
 846         }
 847         if (ret)
 848                 goto fail;
 849
 850         ret = pending_snapshot->error;
 851         if (ret)
 852                 goto fail;
 853
 854         ret = btrfs_orphan_cleanup(pending_snapshot->snap);
 855         if (ret)
 856                 goto fail;
 857
 858         inode = btrfs_lookup_dentry(d_inode(dentry->d_parent), dentry);
 859         if (IS_ERR(inode)) {
 860                 ret = PTR_ERR(inode);
 861                 goto fail;
 862         }
 863
 864         d_instantiate(dentry, inode);
 865         ret = 0;
 866 fail:
 867         btrfs_subvolume_release_metadata(fs_info, &pending_snapshot->block_rsv);
 868 dec_and_free:
 869         if (snapshot_force_cow)
 870                 atomic_dec(&root->snapshot_force_cow);
 871         if (atomic_dec_and_test(&root->will_be_snapshotted))
 872                 wake_up_var(&root->will_be_snapshotted);
 873 free_pending:
 874         kfree(pending_snapshot->root_item);
 875         btrfs_free_path(pending_snapshot->path);
 876         kfree(pending_snapshot);
 877
 878         return ret;
 879 }
 880
 881 /*  copy of may_delete in fs/namei.c()
 882  *      Check whether we can remove a link victim from directory dir, check
 883  *  whether the type of victim is right.
 884  *  1. We can't do it if dir is read-only (done in permission())
 885  *  2. We should have write and exec permissions on dir
 886  *  3. We can't remove anything from append-only dir
 887  *  4. We can't do anything with immutable dir (done in permission())
 888  *  5. If the sticky bit on dir is set we should either
 889  *      a. be owner of dir, or
 890  *      b. be owner of victim, or
 891  *      c. have CAP_FOWNER capability
 892  *  6. If the victim is append-only or immutable we can't do anything with
 893  *     links pointing to it.
 894  *  7. If we were asked to remove a directory and victim isn't one - ENOTDIR.
 895  *  8. If we were asked to remove a non-directory and victim isn't one - EISDIR.
 896  *  9. We can't remove a root or mountpoint.
 897  * 10. We don't allow removal of NFS sillyrenamed files; it's handled by
 898  *     nfs_async_unlink().
 899  */
 900
 901 static int btrfs_may_delete(struct inode *dir, struct dentry *victim, int isdir)
 902 {
 903         int error;
 904
 905         if (d_really_is_negative(victim))
 906                 return -ENOENT;
 907
 908         BUG_ON(d_inode(victim->d_parent) != dir);
 909         audit_inode_child(dir, victim, AUDIT_TYPE_CHILD_DELETE);
 910
 911         error = inode_permission(dir, MAY_WRITE | MAY_EXEC);
 912         if (error)
 913                 return error;
 914         if (IS_APPEND(dir))
 915                 return -EPERM;
 916         if (check_sticky(dir, d_inode(victim)) || IS_APPEND(d_inode(victim)) ||
 917             IS_IMMUTABLE(d_inode(victim)) || IS_SWAPFILE(d_inode(victim)))
 918                 return -EPERM;
 919         if (isdir) {
 920                 if (!d_is_dir(victim))
 921                         return -ENOTDIR;
 922                 if (IS_ROOT(victim))
 923                         return -EBUSY;
 924         } else if (d_is_dir(victim))
 925                 return -EISDIR;
 926         if (IS_DEADDIR(dir))
 927                 return -ENOENT;
 928         if (victim->d_flags & DCACHE_NFSFS_RENAMED)
 929                 return -EBUSY;
 930         return 0;
 931 }
 932
 933 /* copy of may_create in fs/namei.c() */
 934 static inline int btrfs_may_create(struct inode *dir, struct dentry *child)
 935 {
 936         if (d_really_is_positive(child))
 937                 return -EEXIST;
 938         if (IS_DEADDIR(dir))
 939                 return -ENOENT;
 940         return inode_permission(dir, MAY_WRITE | MAY_EXEC);
 941 }
 942
 943 /*
 944  * Create a new subvolume below @parent.  This is largely modeled after
 945  * sys_mkdirat and vfs_mkdir, but we only do a single component lookup
 946  * inside this filesystem so it's quite a bit simpler.
 947  */
 948 static noinline int btrfs_mksubvol(const struct path *parent,
 949                                    const char *name, int namelen,
 950                                    struct btrfs_root *snap_src,
 951                                    u64 *async_transid, bool readonly,
 952                                    struct btrfs_qgroup_inherit *inherit)
 953 {
 954         struct inode *dir = d_inode(parent->dentry);
 955         struct btrfs_fs_info *fs_info = btrfs_sb(dir->i_sb);
 956         struct dentry *dentry;
 957         int error;
 958
 959         error = down_write_killable_nested(&dir->i_rwsem, I_MUTEX_PARENT);
 960         if (error == -EINTR)
 961                 return error;
 962
 963         dentry = lookup_one_len(name, parent->dentry, namelen);
 964         error = PTR_ERR(dentry);
 965         if (IS_ERR(dentry))
 966                 goto out_unlock;
 967
 968         error = btrfs_may_create(dir, dentry);
 969         if (error)
 970                 goto out_dput;
 971
 972         /*
 973          * even if this name doesn't exist, we may get hash collisions.
 974          * check for them now when we can safely fail
 975          */
 976         error = btrfs_check_dir_item_collision(BTRFS_I(dir)->root,
 977                                                dir->i_ino, name,
 978                                                namelen);
 979         if (error)
 980                 goto out_dput;
 981
 982         down_read(&fs_info->subvol_sem);
 983
 984         if (btrfs_root_refs(&BTRFS_I(dir)->root->root_item) == 0)
 985                 goto out_up_read;
 986
 987         if (snap_src) {
 988                 error = create_snapshot(snap_src, dir, dentry,
 989                                         async_transid, readonly, inherit);
 990         } else {
 991                 error = create_subvol(dir, dentry, name, namelen,
 992                                       async_transid, inherit);
 993         }
 994         if (!error)
 995                 fsnotify_mkdir(dir, dentry);
 996 out_up_read:
 997         up_read(&fs_info->subvol_sem);
 998 out_dput:
 999         dput(dentry);
1000 out_unlock:
1001         inode_unlock(dir);
1002         return error;
1003 }
1004
1005 /*
1006  * When we're defragging a range, we don't want to kick it off again
1007  * if it is really just waiting for delalloc to send it down.
1008  * If we find a nice big extent or delalloc range for the bytes in the
1009  * file you want to defrag, we return 0 to let you know to skip this
1010  * part of the file
1011  */
1012 static int check_defrag_in_cache(struct inode *inode, u64 offset, u32 thresh)
1013 {
1014         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
1015         struct extent_map *em = NULL;
1016         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
1017         u64 end;
1018
1019         read_lock(&em_tree->lock);
1020         em = lookup_extent_mapping(em_tree, offset, PAGE_SIZE);
1021         read_unlock(&em_tree->lock);
1022
1023         if (em) {
1024                 end = extent_map_end(em);
1025                 free_extent_map(em);
1026                 if (end - offset > thresh)
1027                         return 0;
1028         }
1029         /* if we already have a nice delalloc here, just stop */
1030         thresh /= 2;
1031         end = count_range_bits(io_tree, &offset, offset + thresh,
1032                                thresh, EXTENT_DELALLOC, 1);
1033         if (end >= thresh)
1034                 return 0;
1035         return 1;
1036 }
1037
1038 /*
1039  * helper function to walk through a file and find extents
1040  * newer than a specific transid, and smaller than thresh.
1041  *
1042  * This is used by the defragging code to find new and small
1043  * extents
1044  */
1045 static int find_new_extents(struct btrfs_root *root,
1046                             struct inode *inode, u64 newer_than,
1047                             u64 *off, u32 thresh)
1048 {
1049         struct btrfs_path *path;
1050         struct btrfs_key min_key;
1051         struct extent_buffer *leaf;
1052         struct btrfs_file_extent_item *extent;
1053         int type;
1054         int ret;
1055         u64 ino = btrfs_ino(BTRFS_I(inode));
1056
1057         path = btrfs_alloc_path();
1058         if (!path)
1059                 return -ENOMEM;
1060
1061         min_key.objectid = ino;
1062         min_key.type = BTRFS_EXTENT_DATA_KEY;
1063         min_key.offset = *off;
1064
1065         while (1) {
1066                 ret = btrfs_search_forward(root, &min_key, path, newer_than);
1067                 if (ret != 0)
1068                         goto none;
1069 process_slot:
1070                 if (min_key.objectid != ino)
1071                         goto none;
1072                 if (min_key.type != BTRFS_EXTENT_DATA_KEY)
1073                         goto none;
1074
1075                 leaf = path->nodes[0];
1076                 extent = btrfs_item_ptr(leaf, path->slots[0],
1077                                         struct btrfs_file_extent_item);
1078
1079                 type = btrfs_file_extent_type(leaf, extent);
1080                 if (type == BTRFS_FILE_EXTENT_REG &&
1081                     btrfs_file_extent_num_bytes(leaf, extent) < thresh &&
1082                     check_defrag_in_cache(inode, min_key.offset, thresh)) {
1083                         *off = min_key.offset;
1084                         btrfs_free_path(path);
1085                         return 0;
1086                 }
1087
1088                 path->slots[0]++;
1089                 if (path->slots[0] < btrfs_header_nritems(leaf)) {
1090                         btrfs_item_key_to_cpu(leaf, &min_key, path->slots[0]);
1091                         goto process_slot;
1092                 }
1093
1094                 if (min_key.offset == (u64)-1)
1095                         goto none;
1096
1097                 min_key.offset++;
1098                 btrfs_release_path(path);
1099         }
1100 none:
1101         btrfs_free_path(path);
1102         return -ENOENT;
1103 }
1104
1105 static struct extent_map *defrag_lookup_extent(struct inode *inode, u64 start)
1106 {
1107         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
1108         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
1109         struct extent_map *em;
1110         u64 len = PAGE_SIZE;
1111
1112         /*
1113          * hopefully we have this extent in the tree already, try without
1114          * the full extent lock
1115          */
1116         read_lock(&em_tree->lock);
1117         em = lookup_extent_mapping(em_tree, start, len);
1118         read_unlock(&em_tree->lock);
1119
1120         if (!em) {
1121                 struct extent_state *cached = NULL;
1122                 u64 end = start + len - 1;
1123
1124                 /* get the big lock and read metadata off disk */
1125                 lock_extent_bits(io_tree, start, end, &cached);
1126                 em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, start, len, 0);
1127                 unlock_extent_cached(io_tree, start, end, &cached);
1128
1129                 if (IS_ERR(em))
1130                         return NULL;
1131         }
1132
1133         return em;
1134 }
1135
1136 static bool defrag_check_next_extent(struct inode *inode, struct extent_map *em)
1137 {
1138         struct extent_map *next;
1139         bool ret = true;
1140
1141         /* this is the last extent */
1142         if (em->start + em->len >= i_size_read(inode))
1143                 return false;
1144
1145         next = defrag_lookup_extent(inode, em->start + em->len);
1146         if (!next || next->block_start >= EXTENT_MAP_LAST_BYTE)
1147                 ret = false;
1148         else if ((em->block_start + em->block_len == next->block_start) &&
1149                  (em->block_len > SZ_128K && next->block_len > SZ_128K))
1150                 ret = false;
1151
1152         free_extent_map(next);
1153         return ret;
1154 }
1155
1156 static int should_defrag_range(struct inode *inode, u64 start, u32 thresh,
1157                                u64 *last_len, u64 *skip, u64 *defrag_end,
1158                                int compress)
1159 {
1160         struct extent_map *em;
1161         int ret = 1;
1162         bool next_mergeable = true;
1163         bool prev_mergeable = true;
1164
1165         /*
1166          * make sure that once we start defragging an extent, we keep on
1167          * defragging it
1168          */
1169         if (start < *defrag_end)
1170                 return 1;
1171
1172         *skip = 0;
1173
1174         em = defrag_lookup_extent(inode, start);
1175         if (!em)
1176                 return 0;
1177
1178         /* this will cover holes, and inline extents */
1179         if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
1180                 ret = 0;
1181                 goto out;
1182         }
1183
1184         if (!*defrag_end)
1185                 prev_mergeable = false;
1186
1187         next_mergeable = defrag_check_next_extent(inode, em);
1188         /*
1189          * we hit a real extent, if it is big or the next extent is not a
1190          * real extent, don't bother defragging it
1191          */
1192         if (!compress && (*last_len == 0 || *last_len >= thresh) &&
1193             (em->len >= thresh || (!next_mergeable && !prev_mergeable)))
1194                 ret = 0;
1195 out:
1196         /*
1197          * last_len ends up being a counter of how many bytes we've defragged.
1198          * every time we choose not to defrag an extent, we reset *last_len
1199          * so that the next tiny extent will force a defrag.
1200          *
1201          * The end result of this is that tiny extents before a single big
1202          * extent will force at least part of that big extent to be defragged.
1203          */
1204         if (ret) {
1205                 *defrag_end = extent_map_end(em);
1206         } else {
1207                 *last_len = 0;
1208                 *skip = extent_map_end(em);
1209                 *defrag_end = 0;
1210         }
1211
1212         free_extent_map(em);
1213         return ret;
1214 }
1215
1216 /*
1217  * it doesn't do much good to defrag one or two pages
1218  * at a time.  This pulls in a nice chunk of pages
1219  * to COW and defrag.
1220  *
1221  * It also makes sure the delalloc code has enough
1222  * dirty data to avoid making new small extents as part
1223  * of the defrag
1224  *
1225  * It's a good idea to start RA on this range
1226  * before calling this.
1227  */
1228 static int cluster_pages_for_defrag(struct inode *inode,
1229                                     struct page **pages,
1230                                     unsigned long start_index,
1231                                     unsigned long num_pages)
1232 {
1233         unsigned long file_end;
1234         u64 isize = i_size_read(inode);
1235         u64 page_start;
1236         u64 page_end;
1237         u64 page_cnt;
1238         int ret;
1239         int i;
1240         int i_done;
1241         struct btrfs_ordered_extent *ordered;
1242         struct extent_state *cached_state = NULL;
1243         struct extent_io_tree *tree;
1244         struct extent_changeset *data_reserved = NULL;
1245         gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
1246
1247         file_end = (isize - 1) >> PAGE_SHIFT;
1248         if (!isize || start_index > file_end)
1249                 return 0;
1250
1251         page_cnt = min_t(u64, (u64)num_pages, (u64)file_end - start_index + 1);
1252
1253         ret = btrfs_delalloc_reserve_space(inode, &data_reserved,
1254                         start_index << PAGE_SHIFT,
1255                         page_cnt << PAGE_SHIFT);
1256         if (ret)
1257                 return ret;
1258         i_done = 0;
1259         tree = &BTRFS_I(inode)->io_tree;
1260
1261         /* step one, lock all the pages */
1262         for (i = 0; i < page_cnt; i++) {
1263                 struct page *page;
1264 again:
1265                 page = find_or_create_page(inode->i_mapping,
1266                                            start_index + i, mask);
1267                 if (!page)
1268                         break;
1269
1270                 page_start = page_offset(page);
1271                 page_end = page_start + PAGE_SIZE - 1;
1272                 while (1) {
1273                         lock_extent_bits(tree, page_start, page_end,
1274                                          &cached_state);
1275                         ordered = btrfs_lookup_ordered_extent(inode,
1276                                                               page_start);
1277                         unlock_extent_cached(tree, page_start, page_end,
1278                                              &cached_state);
1279                         if (!ordered)
1280                                 break;
1281
1282                         unlock_page(page);
1283                         btrfs_start_ordered_extent(inode, ordered, 1);
1284                         btrfs_put_ordered_extent(ordered);
1285                         lock_page(page);
1286                         /*
1287                          * we unlocked the page above, so we need check if
1288                          * it was released or not.
1289                          */
1290                         if (page->mapping != inode->i_mapping) {
1291                                 unlock_page(page);
1292                                 put_page(page);
1293                                 goto again;
1294                         }
1295                 }
1296
1297                 if (!PageUptodate(page)) {
1298                         btrfs_readpage(NULL, page);
1299                         lock_page(page);
1300                         if (!PageUptodate(page)) {
1301                                 unlock_page(page);
1302                                 put_page(page);
1303                                 ret = -EIO;
1304                                 break;
1305                         }
1306                 }
1307
1308                 if (page->mapping != inode->i_mapping) {
1309                         unlock_page(page);
1310                         put_page(page);
1311                         goto again;
1312                 }
1313
1314                 pages[i] = page;
1315                 i_done++;
1316         }
1317         if (!i_done || ret)
1318                 goto out;
1319
1320         if (!(inode->i_sb->s_flags & SB_ACTIVE))
1321                 goto out;
1322
1323         /*
1324          * so now we have a nice long stream of locked
1325          * and up to date pages, lets wait on them
1326          */
1327         for (i = 0; i < i_done; i++)
1328                 wait_on_page_writeback(pages[i]);
1329
1330         page_start = page_offset(pages[0]);
1331         page_end = page_offset(pages[i_done - 1]) + PAGE_SIZE;
1332
1333         lock_extent_bits(&BTRFS_I(inode)->io_tree,
1334                          page_start, page_end - 1, &cached_state);
1335         clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start,
1336                           page_end - 1, EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING |
1337                           EXTENT_DEFRAG, 0, 0, &cached_state);
1338
1339         if (i_done != page_cnt) {
1340                 spin_lock(&BTRFS_I(inode)->lock);
1341                 btrfs_mod_outstanding_extents(BTRFS_I(inode), 1);
1342                 spin_unlock(&BTRFS_I(inode)->lock);
1343                 btrfs_delalloc_release_space(inode, data_reserved,
1344                                 start_index << PAGE_SHIFT,
1345                                 (page_cnt - i_done) << PAGE_SHIFT, true);
1346         }
1347
1348
1349         set_extent_defrag(&BTRFS_I(inode)->io_tree, page_start, page_end - 1,
1350                           &cached_state);
1351
1352         unlock_extent_cached(&BTRFS_I(inode)->io_tree,
1353                              page_start, page_end - 1, &cached_state);
1354
1355         for (i = 0; i < i_done; i++) {
1356                 clear_page_dirty_for_io(pages[i]);
1357                 ClearPageChecked(pages[i]);
1358                 set_page_extent_mapped(pages[i]);
1359                 set_page_dirty(pages[i]);
1360                 unlock_page(pages[i]);
1361                 put_page(pages[i]);
1362         }
1363         btrfs_delalloc_release_extents(BTRFS_I(inode), page_cnt << PAGE_SHIFT,
1364                                        false);
1365         extent_changeset_free(data_reserved);
1366         return i_done;
1367 out:
1368         for (i = 0; i < i_done; i++) {
1369                 unlock_page(pages[i]);
1370                 put_page(pages[i]);
1371         }
1372         btrfs_delalloc_release_space(inode, data_reserved,
1373                         start_index << PAGE_SHIFT,
1374                         page_cnt << PAGE_SHIFT, true);
1375         btrfs_delalloc_release_extents(BTRFS_I(inode), page_cnt << PAGE_SHIFT,
1376                                        true);
1377         extent_changeset_free(data_reserved);
1378         return ret;
1379
1380 }
1381
1382 int btrfs_defrag_file(struct inode *inode, struct file *file,
1383                       struct btrfs_ioctl_defrag_range_args *range,
1384                       u64 newer_than, unsigned long max_to_defrag)
1385 {
1386         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1387         struct btrfs_root *root = BTRFS_I(inode)->root;
1388         struct file_ra_state *ra = NULL;
1389         unsigned long last_index;
1390         u64 isize = i_size_read(inode);
1391         u64 last_len = 0;
1392         u64 skip = 0;
1393         u64 defrag_end = 0;
1394         u64 newer_off = range->start;
1395         unsigned long i;
1396         unsigned long ra_index = 0;
1397         int ret;
1398         int defrag_count = 0;
1399         int compress_type = BTRFS_COMPRESS_ZLIB;
1400         u32 extent_thresh = range->extent_thresh;
1401         unsigned long max_cluster = SZ_256K >> PAGE_SHIFT;
1402         unsigned long cluster = max_cluster;
1403         u64 new_align = ~((u64)SZ_128K - 1);
1404         struct page **pages = NULL;
1405         bool do_compress = range->flags & BTRFS_DEFRAG_RANGE_COMPRESS;
1406
1407         if (isize == 0)
1408                 return 0;
1409
1410         if (range->start >= isize)
1411                 return -EINVAL;
1412
1413         if (do_compress) {
1414                 if (range->compress_type > BTRFS_COMPRESS_TYPES)
1415                         return -EINVAL;
1416                 if (range->compress_type)
1417                         compress_type = range->compress_type;
1418         }
1419
1420         if (extent_thresh == 0)
1421                 extent_thresh = SZ_256K;
1422
1423         /*
1424          * If we were not given a file, allocate a readahead context. As
1425          * readahead is just an optimization, defrag will work without it so
1426          * we don't error out.
1427          */
1428         if (!file) {
1429                 ra = kzalloc(sizeof(*ra), GFP_KERNEL);
1430                 if (ra)
1431                         file_ra_state_init(ra, inode->i_mapping);
1432         } else {
1433                 ra = &file->f_ra;
1434         }
1435
1436         pages = kmalloc_array(max_cluster, sizeof(struct page *), GFP_KERNEL);
1437         if (!pages) {
1438                 ret = -ENOMEM;
1439                 goto out_ra;
1440         }
1441
1442         /* find the last page to defrag */
1443         if (range->start + range->len > range->start) {
1444                 last_index = min_t(u64, isize - 1,
1445                          range->start + range->len - 1) >> PAGE_SHIFT;
1446         } else {
1447                 last_index = (isize - 1) >> PAGE_SHIFT;
1448         }
1449
1450         if (newer_than) {
1451                 ret = find_new_extents(root, inode, newer_than,
1452                                        &newer_off, SZ_64K);
1453                 if (!ret) {
1454                         range->start = newer_off;
1455                         /*
1456                          * we always align our defrag to help keep
1457                          * the extents in the file evenly spaced
1458                          */
1459                         i = (newer_off & new_align) >> PAGE_SHIFT;
1460                 } else
1461                         goto out_ra;
1462         } else {
1463                 i = range->start >> PAGE_SHIFT;
1464         }
1465         if (!max_to_defrag)
1466                 max_to_defrag = last_index - i + 1;
1467
1468         /*
1469          * make writeback starts from i, so the defrag range can be
1470          * written sequentially.
1471          */
1472         if (i < inode->i_mapping->writeback_index)
1473                 inode->i_mapping->writeback_index = i;
1474
1475         while (i <= last_index && defrag_count < max_to_defrag &&
1476                (i < DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE))) {
1477                 /*
1478                  * make sure we stop running if someone unmounts
1479                  * the FS
1480                  */
1481                 if (!(inode->i_sb->s_flags & SB_ACTIVE))
1482                         break;
1483
1484                 if (btrfs_defrag_cancelled(fs_info)) {
1485                         btrfs_debug(fs_info, "defrag_file cancelled");
1486                         ret = -EAGAIN;
1487                         break;
1488                 }
1489
1490                 if (!should_defrag_range(inode, (u64)i << PAGE_SHIFT,
1491                                          extent_thresh, &last_len, &skip,
1492                                          &defrag_end, do_compress)){
1493                         unsigned long next;
1494                         /*
1495                          * the should_defrag function tells us how much to skip
1496                          * bump our counter by the suggested amount
1497                          */
1498                         next = DIV_ROUND_UP(skip, PAGE_SIZE);
1499                         i = max(i + 1, next);
1500                         continue;
1501                 }
1502
1503                 if (!newer_than) {
1504                         cluster = (PAGE_ALIGN(defrag_end) >>
1505                                    PAGE_SHIFT) - i;
1506                         cluster = min(cluster, max_cluster);
1507                 } else {
1508                         cluster = max_cluster;
1509                 }
1510
1511                 if (i + cluster > ra_index) {
1512                         ra_index = max(i, ra_index);
1513                         if (ra)
1514                                 page_cache_sync_readahead(inode->i_mapping, ra,
1515                                                 file, ra_index, cluster);
1516                         ra_index += cluster;
1517                 }
1518
1519                 inode_lock(inode);
1520                 if (IS_SWAPFILE(inode)) {
1521                         ret = -ETXTBSY;
1522                 } else {
1523                         if (do_compress)
1524                                 BTRFS_I(inode)->defrag_compress = compress_type;
1525                         ret = cluster_pages_for_defrag(inode, pages, i, cluster);
1526                 }
1527                 if (ret < 0) {
1528                         inode_unlock(inode);
1529                         goto out_ra;
1530                 }
1531
1532                 defrag_count += ret;
1533                 balance_dirty_pages_ratelimited(inode->i_mapping);
1534                 inode_unlock(inode);
1535
1536                 if (newer_than) {
1537                         if (newer_off == (u64)-1)
1538                                 break;
1539
1540                         if (ret > 0)
1541                                 i += ret;
1542
1543                         newer_off = max(newer_off + 1,
1544                                         (u64)i << PAGE_SHIFT);
1545
1546                         ret = find_new_extents(root, inode, newer_than,
1547                                                &newer_off, SZ_64K);
1548                         if (!ret) {
1549                                 range->start = newer_off;
1550                                 i = (newer_off & new_align) >> PAGE_SHIFT;
1551                         } else {
1552                                 break;
1553                         }
1554                 } else {
1555                         if (ret > 0) {
1556                                 i += ret;
1557                                 last_len += ret << PAGE_SHIFT;
1558                         } else {
1559                                 i++;
1560                                 last_len = 0;
1561                         }
1562                 }
1563         }
1564
1565         if ((range->flags & BTRFS_DEFRAG_RANGE_START_IO)) {
1566                 filemap_flush(inode->i_mapping);
1567                 if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
1568                              &BTRFS_I(inode)->runtime_flags))
1569                         filemap_flush(inode->i_mapping);
1570         }
1571
1572         if (range->compress_type == BTRFS_COMPRESS_LZO) {
1573                 btrfs_set_fs_incompat(fs_info, COMPRESS_LZO);
1574         } else if (range->compress_type == BTRFS_COMPRESS_ZSTD) {
1575                 btrfs_set_fs_incompat(fs_info, COMPRESS_ZSTD);
1576         }
1577
1578         ret = defrag_count;
1579
1580 out_ra:
1581         if (do_compress) {
1582                 inode_lock(inode);
1583                 BTRFS_I(inode)->defrag_compress = BTRFS_COMPRESS_NONE;
1584                 inode_unlock(inode);
1585         }
1586         if (!file)
1587                 kfree(ra);
1588         kfree(pages);
1589         return ret;
1590 }
1591
1592 static noinline int btrfs_ioctl_resize(struct file *file,
1593                                         void __user *arg)
1594 {
1595         struct inode *inode = file_inode(file);
1596         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1597         u64 new_size;
1598         u64 old_size;
1599         u64 devid = 1;
1600         struct btrfs_root *root = BTRFS_I(inode)->root;
1601         struct btrfs_ioctl_vol_args *vol_args;
1602         struct btrfs_trans_handle *trans;
1603         struct btrfs_device *device = NULL;
1604         char *sizestr;
1605         char *retptr;
1606         char *devstr = NULL;
1607         int ret = 0;
1608         int mod = 0;
1609
1610         if (!capable(CAP_SYS_ADMIN))
1611                 return -EPERM;
1612
1613         ret = mnt_want_write_file(file);
1614         if (ret)
1615                 return ret;
1616
1617         if (test_and_set_bit(BTRFS_FS_EXCL_OP, &fs_info->flags)) {
1618                 mnt_drop_write_file(file);
1619                 return BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
1620         }
1621
1622         vol_args = memdup_user(arg, sizeof(*vol_args));
1623         if (IS_ERR(vol_args)) {
1624                 ret = PTR_ERR(vol_args);
1625                 goto out;
1626         }
1627
1628         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
1629
1630         sizestr = vol_args->name;
1631         devstr = strchr(sizestr, ':');
1632         if (devstr) {
1633                 sizestr = devstr + 1;
1634                 *devstr = '\0';
1635                 devstr = vol_args->name;
1636                 ret = kstrtoull(devstr, 10, &devid);
1637                 if (ret)
1638                         goto out_free;
1639                 if (!devid) {
1640                         ret = -EINVAL;
1641                         goto out_free;
1642                 }
1643                 btrfs_info(fs_info, "resizing devid %llu", devid);
1644         }
1645
1646         device = btrfs_find_device(fs_info->fs_devices, devid, NULL, NULL, true);
1647         if (!device) {
1648                 btrfs_info(fs_info, "resizer unable to find device %llu",
1649                            devid);
1650                 ret = -ENODEV;
1651                 goto out_free;
1652         }
1653
1654         if (!test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state)) {
1655                 btrfs_info(fs_info,
1656                            "resizer unable to apply on readonly device %llu",
1657                        devid);
1658                 ret = -EPERM;
1659                 goto out_free;
1660         }
1661
1662         if (!strcmp(sizestr, "max"))
1663                 new_size = device->bdev->bd_inode->i_size;
1664         else {
1665                 if (sizestr[0] == '-') {
1666                         mod = -1;
1667                         sizestr++;
1668                 } else if (sizestr[0] == '+') {
1669                         mod = 1;
1670                         sizestr++;
1671                 }
1672                 new_size = memparse(sizestr, &retptr);
1673                 if (*retptr != '\0' || new_size == 0) {
1674                         ret = -EINVAL;
1675                         goto out_free;
1676                 }
1677         }
1678
1679         if (test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state)) {
1680                 ret = -EPERM;
1681                 goto out_free;
1682         }
1683
1684         old_size = btrfs_device_get_total_bytes(device);
1685
1686         if (mod < 0) {
1687                 if (new_size > old_size) {
1688                         ret = -EINVAL;
1689                         goto out_free;
1690                 }
1691                 new_size = old_size - new_size;
1692         } else if (mod > 0) {
1693                 if (new_size > ULLONG_MAX - old_size) {
1694                         ret = -ERANGE;
1695                         goto out_free;
1696                 }
1697                 new_size = old_size + new_size;
1698         }
1699
1700         if (new_size < SZ_256M) {
1701                 ret = -EINVAL;
1702                 goto out_free;
1703         }
1704         if (new_size > device->bdev->bd_inode->i_size) {
1705                 ret = -EFBIG;
1706                 goto out_free;
1707         }
1708
1709         new_size = round_down(new_size, fs_info->sectorsize);
1710
1711         btrfs_info_in_rcu(fs_info, "new size for %s is %llu",
1712                           rcu_str_deref(device->name), new_size);
1713
1714         if (new_size > old_size) {
1715                 trans = btrfs_start_transaction(root, 0);
1716                 if (IS_ERR(trans)) {
1717                         ret = PTR_ERR(trans);
1718                         goto out_free;
1719                 }
1720                 ret = btrfs_grow_device(trans, device, new_size);
1721                 btrfs_commit_transaction(trans);
1722         } else if (new_size < old_size) {
1723                 ret = btrfs_shrink_device(device, new_size);
1724         } /* equal, nothing need to do */
1725
1726 out_free:
1727         kfree(vol_args);
1728 out:
1729         clear_bit(BTRFS_FS_EXCL_OP, &fs_info->flags);
1730         mnt_drop_write_file(file);
1731         return ret;
1732 }
1733
1734 static noinline int btrfs_ioctl_snap_create_transid(struct file *file,
1735                                 const char *name, unsigned long fd, int subvol,
1736                                 u64 *transid, bool readonly,
1737                                 struct btrfs_qgroup_inherit *inherit)
1738 {
1739         int namelen;
1740         int ret = 0;
1741
1742         if (!S_ISDIR(file_inode(file)->i_mode))
1743                 return -ENOTDIR;
1744
1745         ret = mnt_want_write_file(file);
1746         if (ret)
1747                 goto out;
1748
1749         namelen = strlen(name);
1750         if (strchr(name, '/')) {
1751                 ret = -EINVAL;
1752                 goto out_drop_write;
1753         }
1754
1755         if (name[0] == '.' &&
1756            (namelen == 1 || (name[1] == '.' && namelen == 2))) {
1757                 ret = -EEXIST;
1758                 goto out_drop_write;
1759         }
1760
1761         if (subvol) {
1762                 ret = btrfs_mksubvol(&file->f_path, name, namelen,
1763                                      NULL, transid, readonly, inherit);
1764         } else {
1765                 struct fd src = fdget(fd);
1766                 struct inode *src_inode;
1767                 if (!src.file) {
1768                         ret = -EINVAL;
1769                         goto out_drop_write;
1770                 }
1771
1772                 src_inode = file_inode(src.file);
1773                 if (src_inode->i_sb != file_inode(file)->i_sb) {
1774                         btrfs_info(BTRFS_I(file_inode(file))->root->fs_info,
1775                                    "Snapshot src from another FS");
1776                         ret = -EXDEV;
1777                 } else if (!inode_owner_or_capable(src_inode)) {
1778                         /*
1779                          * Subvolume creation is not restricted, but snapshots
1780                          * are limited to own subvolumes only
1781                          */
1782                         ret = -EPERM;
1783                 } else {
1784                         ret = btrfs_mksubvol(&file->f_path, name, namelen,
1785                                              BTRFS_I(src_inode)->root,
1786                                              transid, readonly, inherit);
1787                 }
1788                 fdput(src);
1789         }
1790 out_drop_write:
1791         mnt_drop_write_file(file);
1792 out:
1793         return ret;
1794 }
1795
1796 static noinline int btrfs_ioctl_snap_create(struct file *file,
1797                                             void __user *arg, int subvol)
1798 {
1799         struct btrfs_ioctl_vol_args *vol_args;
1800         int ret;
1801
1802         if (!S_ISDIR(file_inode(file)->i_mode))
1803                 return -ENOTDIR;
1804
1805         vol_args = memdup_user(arg, sizeof(*vol_args));
1806         if (IS_ERR(vol_args))
1807                 return PTR_ERR(vol_args);
1808         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
1809
1810         ret = btrfs_ioctl_snap_create_transid(file, vol_args->name,
1811                                               vol_args->fd, subvol,
1812                                               NULL, false, NULL);
1813
1814         kfree(vol_args);
1815         return ret;
1816 }
1817
1818 static noinline int btrfs_ioctl_snap_create_v2(struct file *file,
1819                                                void __user *arg, int subvol)
1820 {
1821         struct btrfs_ioctl_vol_args_v2 *vol_args;
1822         int ret;
1823         u64 transid = 0;
1824         u64 *ptr = NULL;
1825         bool readonly = false;
1826         struct btrfs_qgroup_inherit *inherit = NULL;
1827
1828         if (!S_ISDIR(file_inode(file)->i_mode))
1829                 return -ENOTDIR;
1830
1831         vol_args = memdup_user(arg, sizeof(*vol_args));
1832         if (IS_ERR(vol_args))
1833                 return PTR_ERR(vol_args);
1834         vol_args->name[BTRFS_SUBVOL_NAME_MAX] = '\0';
1835
1836         if (vol_args->flags &
1837             ~(BTRFS_SUBVOL_CREATE_ASYNC | BTRFS_SUBVOL_RDONLY |
1838               BTRFS_SUBVOL_QGROUP_INHERIT)) {
1839                 ret = -EOPNOTSUPP;
1840                 goto free_args;
1841         }
1842
1843         if (vol_args->flags & BTRFS_SUBVOL_CREATE_ASYNC) {
1844                 struct inode *inode = file_inode(file);
1845                 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1846
1847                 btrfs_warn(fs_info,
1848 "SNAP_CREATE_V2 ioctl with CREATE_ASYNC is deprecated and will be removed in kernel 5.7");
1849
1850                 ptr = &transid;
1851         }
1852         if (vol_args->flags & BTRFS_SUBVOL_RDONLY)
1853                 readonly = true;
1854         if (vol_args->flags & BTRFS_SUBVOL_QGROUP_INHERIT) {
1855                 if (vol_args->size > PAGE_SIZE) {
1856                         ret = -EINVAL;
1857                         goto free_args;
1858                 }
1859                 inherit = memdup_user(vol_args->qgroup_inherit, vol_args->size);
1860                 if (IS_ERR(inherit)) {
1861                         ret = PTR_ERR(inherit);
1862                         goto free_args;
1863                 }
1864         }
1865
1866         ret = btrfs_ioctl_snap_create_transid(file, vol_args->name,
1867                                               vol_args->fd, subvol, ptr,
1868                                               readonly, inherit);
1869         if (ret)
1870                 goto free_inherit;
1871
1872         if (ptr && copy_to_user(arg +
1873                                 offsetof(struct btrfs_ioctl_vol_args_v2,
1874                                         transid),
1875                                 ptr, sizeof(*ptr)))
1876                 ret = -EFAULT;
1877
1878 free_inherit:
1879         kfree(inherit);
1880 free_args:
1881         kfree(vol_args);
1882         return ret;
1883 }
1884
1885 static noinline int btrfs_ioctl_subvol_getflags(struct file *file,
1886                                                 void __user *arg)
1887 {
1888         struct inode *inode = file_inode(file);
1889         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1890         struct btrfs_root *root = BTRFS_I(inode)->root;
1891         int ret = 0;
1892         u64 flags = 0;
1893
1894         if (btrfs_ino(BTRFS_I(inode)) != BTRFS_FIRST_FREE_OBJECTID)
1895                 return -EINVAL;
1896
1897         down_read(&fs_info->subvol_sem);
1898         if (btrfs_root_readonly(root))
1899                 flags |= BTRFS_SUBVOL_RDONLY;
1900         up_read(&fs_info->subvol_sem);
1901
1902         if (copy_to_user(arg, &flags, sizeof(flags)))
1903                 ret = -EFAULT;
1904
1905         return ret;
1906 }
1907
1908 static noinline int btrfs_ioctl_subvol_setflags(struct file *file,
1909                                               void __user *arg)
1910 {
1911         struct inode *inode = file_inode(file);
1912         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
1913         struct btrfs_root *root = BTRFS_I(inode)->root;
1914         struct btrfs_trans_handle *trans;
1915         u64 root_flags;
1916         u64 flags;
1917         int ret = 0;
1918
1919         if (!inode_owner_or_capable(inode))
1920                 return -EPERM;
1921
1922         ret = mnt_want_write_file(file);
1923         if (ret)
1924                 goto out;
1925
1926         if (btrfs_ino(BTRFS_I(inode)) != BTRFS_FIRST_FREE_OBJECTID) {
1927                 ret = -EINVAL;
1928                 goto out_drop_write;
1929         }
1930
1931         if (copy_from_user(&flags, arg, sizeof(flags))) {
1932                 ret = -EFAULT;
1933                 goto out_drop_write;
1934         }
1935
1936         if (flags & BTRFS_SUBVOL_CREATE_ASYNC) {
1937                 ret = -EINVAL;
1938                 goto out_drop_write;
1939         }
1940
1941         if (flags & ~BTRFS_SUBVOL_RDONLY) {
1942                 ret = -EOPNOTSUPP;
1943                 goto out_drop_write;
1944         }
1945
1946         down_write(&fs_info->subvol_sem);
1947
1948         /* nothing to do */
1949         if (!!(flags & BTRFS_SUBVOL_RDONLY) == btrfs_root_readonly(root))
1950                 goto out_drop_sem;
1951
1952         root_flags = btrfs_root_flags(&root->root_item);
1953         if (flags & BTRFS_SUBVOL_RDONLY) {
1954                 btrfs_set_root_flags(&root->root_item,
1955                                      root_flags | BTRFS_ROOT_SUBVOL_RDONLY);
1956         } else {
1957                 /*
1958                  * Block RO -> RW transition if this subvolume is involved in
1959                  * send
1960                  */
1961                 spin_lock(&root->root_item_lock);
1962                 if (root->send_in_progress == 0) {
1963                         btrfs_set_root_flags(&root->root_item,
1964                                      root_flags & ~BTRFS_ROOT_SUBVOL_RDONLY);
1965                         spin_unlock(&root->root_item_lock);
1966                 } else {
1967                         spin_unlock(&root->root_item_lock);
1968                         btrfs_warn(fs_info,
1969                                    "Attempt to set subvolume %llu read-write during send",
1970                                    root->root_key.objectid);
1971                         ret = -EPERM;
1972                         goto out_drop_sem;
1973                 }
1974         }
1975
1976         trans = btrfs_start_transaction(root, 1);
1977         if (IS_ERR(trans)) {
1978                 ret = PTR_ERR(trans);
1979                 goto out_reset;
1980         }
1981
1982         ret = btrfs_update_root(trans, fs_info->tree_root,
1983                                 &root->root_key, &root->root_item);
1984         if (ret < 0) {
1985                 btrfs_end_transaction(trans);
1986                 goto out_reset;
1987         }
1988
1989         ret = btrfs_commit_transaction(trans);
1990
1991 out_reset:
1992         if (ret)
1993                 btrfs_set_root_flags(&root->root_item, root_flags);
1994 out_drop_sem:
1995         up_write(&fs_info->subvol_sem);
1996 out_drop_write:
1997         mnt_drop_write_file(file);
1998 out:
1999         return ret;
2000 }
2001
2002 static noinline int key_in_sk(struct btrfs_key *key,
2003                               struct btrfs_ioctl_search_key *sk)
2004 {
2005         struct btrfs_key test;
2006         int ret;
2007
2008         test.objectid = sk->min_objectid;
2009         test.type = sk->min_type;
2010         test.offset = sk->min_offset;
2011
2012         ret = btrfs_comp_cpu_keys(key, &test);
2013         if (ret < 0)
2014                 return 0;
2015
2016         test.objectid = sk->max_objectid;
2017         test.type = sk->max_type;
2018         test.offset = sk->max_offset;
2019
2020         ret = btrfs_comp_cpu_keys(key, &test);
2021         if (ret > 0)
2022                 return 0;
2023         return 1;
2024 }
2025
2026 static noinline int copy_to_sk(struct btrfs_path *path,
2027                                struct btrfs_key *key,
2028                                struct btrfs_ioctl_search_key *sk,
2029                                size_t *buf_size,
2030                                char __user *ubuf,
2031                                unsigned long *sk_offset,
2032                                int *num_found)
2033 {
2034         u64 found_transid;
2035         struct extent_buffer *leaf;
2036         struct btrfs_ioctl_search_header sh;
2037         struct btrfs_key test;
2038         unsigned long item_off;
2039         unsigned long item_len;
2040         int nritems;
2041         int i;
2042         int slot;
2043         int ret = 0;
2044
2045         leaf = path->nodes[0];
2046         slot = path->slots[0];
2047         nritems = btrfs_header_nritems(leaf);
2048
2049         if (btrfs_header_generation(leaf) > sk->max_transid) {
2050                 i = nritems;
2051                 goto advance_key;
2052         }
2053         found_transid = btrfs_header_generation(leaf);
2054
2055         for (i = slot; i < nritems; i++) {
2056                 item_off = btrfs_item_ptr_offset(leaf, i);
2057                 item_len = btrfs_item_size_nr(leaf, i);
2058
2059                 btrfs_item_key_to_cpu(leaf, key, i);
2060                 if (!key_in_sk(key, sk))
2061                         continue;
2062
2063                 if (sizeof(sh) + item_len > *buf_size) {
2064                         if (*num_found) {
2065                                 ret = 1;
2066                                 goto out;
2067                         }
2068
2069                         /*
2070                          * return one empty item back for v1, which does not
2071                          * handle -EOVERFLOW
2072                          */
2073
2074                         *buf_size = sizeof(sh) + item_len;
2075                         item_len = 0;
2076                         ret = -EOVERFLOW;
2077                 }
2078
2079                 if (sizeof(sh) + item_len + *sk_offset > *buf_size) {
2080                         ret = 1;
2081                         goto out;
2082                 }
2083
2084                 sh.objectid = key->objectid;
2085                 sh.offset = key->offset;
2086                 sh.type = key->type;
2087                 sh.len = item_len;
2088                 sh.transid = found_transid;
2089
2090                 /* copy search result header */
2091                 if (copy_to_user(ubuf + *sk_offset, &sh, sizeof(sh))) {
2092                         ret = -EFAULT;
2093                         goto out;
2094                 }
2095
2096                 *sk_offset += sizeof(sh);
2097
2098                 if (item_len) {
2099                         char __user *up = ubuf + *sk_offset;
2100                         /* copy the item */
2101                         if (read_extent_buffer_to_user(leaf, up,
2102                                                        item_off, item_len)) {
2103                                 ret = -EFAULT;
2104                                 goto out;
2105                         }
2106
2107                         *sk_offset += item_len;
2108                 }
2109                 (*num_found)++;
2110
2111                 if (ret) /* -EOVERFLOW from above */
2112                         goto out;
2113
2114                 if (*num_found >= sk->nr_items) {
2115                         ret = 1;
2116                         goto out;
2117                 }
2118         }
2119 advance_key:
2120         ret = 0;
2121         test.objectid = sk->max_objectid;
2122         test.type = sk->max_type;
2123         test.offset = sk->max_offset;
2124         if (btrfs_comp_cpu_keys(key, &test) >= 0)
2125                 ret = 1;
2126         else if (key->offset < (u64)-1)
2127                 key->offset++;
2128         else if (key->type < (u8)-1) {
2129                 key->offset = 0;
2130                 key->type++;
2131         } else if (key->objectid < (u64)-1) {
2132                 key->offset = 0;
2133                 key->type = 0;
2134                 key->objectid++;
2135         } else
2136                 ret = 1;
2137 out:
2138         /*
2139          *  0: all items from this leaf copied, continue with next
2140          *  1: * more items can be copied, but unused buffer is too small
2141          *     * all items were found
2142          *     Either way, it will stops the loop which iterates to the next
2143          *     leaf
2144          *  -EOVERFLOW: item was to large for buffer
2145          *  -EFAULT: could not copy extent buffer back to userspace
2146          */
2147         return ret;
2148 }
2149
2150 static noinline int search_ioctl(struct inode *inode,
2151                                  struct btrfs_ioctl_search_key *sk,
2152                                  size_t *buf_size,
2153                                  char __user *ubuf)
2154 {
2155         struct btrfs_fs_info *info = btrfs_sb(inode->i_sb);
2156         struct btrfs_root *root;
2157         struct btrfs_key key;
2158         struct btrfs_path *path;
2159         int ret;
2160         int num_found = 0;
2161         unsigned long sk_offset = 0;
2162
2163         if (*buf_size < sizeof(struct btrfs_ioctl_search_header)) {
2164                 *buf_size = sizeof(struct btrfs_ioctl_search_header);
2165                 return -EOVERFLOW;
2166         }
2167
2168         path = btrfs_alloc_path();
2169         if (!path)
2170                 return -ENOMEM;
2171
2172         if (sk->tree_id == 0) {
2173                 /* search the root of the inode that was passed */
2174                 root = BTRFS_I(inode)->root;
2175         } else {
2176                 key.objectid = sk->tree_id;
2177                 key.type = BTRFS_ROOT_ITEM_KEY;
2178                 key.offset = (u64)-1;
2179                 root = btrfs_read_fs_root_no_name(info, &key);
2180                 if (IS_ERR(root)) {
2181                         btrfs_free_path(path);
2182                         return PTR_ERR(root);
2183                 }
2184         }
2185
2186         key.objectid = sk->min_objectid;
2187         key.type = sk->min_type;
2188         key.offset = sk->min_offset;
2189
2190         while (1) {
2191                 ret = btrfs_search_forward(root, &key, path, sk->min_transid);
2192                 if (ret != 0) {
2193                         if (ret > 0)
2194                                 ret = 0;
2195                         goto err;
2196                 }
2197                 ret = copy_to_sk(path, &key, sk, buf_size, ubuf,
2198                                  &sk_offset, &num_found);
2199                 btrfs_release_path(path);
2200                 if (ret)
2201                         break;
2202
2203         }
2204         if (ret > 0)
2205                 ret = 0;
2206 err:
2207         sk->nr_items = num_found;
2208         btrfs_free_path(path);
2209         return ret;
2210 }
2211
2212 static noinline int btrfs_ioctl_tree_search(struct file *file,
2213                                            void __user *argp)
2214 {
2215         struct btrfs_ioctl_search_args __user *uargs;
2216         struct btrfs_ioctl_search_key sk;
2217         struct inode *inode;
2218         int ret;
2219         size_t buf_size;
2220
2221         if (!capable(CAP_SYS_ADMIN))
2222                 return -EPERM;
2223
2224         uargs = (struct btrfs_ioctl_search_args __user *)argp;
2225
2226         if (copy_from_user(&sk, &uargs->key, sizeof(sk)))
2227                 return -EFAULT;
2228
2229         buf_size = sizeof(uargs->buf);
2230
2231         inode = file_inode(file);
2232         ret = search_ioctl(inode, &sk, &buf_size, uargs->buf);
2233
2234         /*
2235          * In the origin implementation an overflow is handled by returning a
2236          * search header with a len of zero, so reset ret.
2237          */
2238         if (ret == -EOVERFLOW)
2239                 ret = 0;
2240
2241         if (ret == 0 && copy_to_user(&uargs->key, &sk, sizeof(sk)))
2242                 ret = -EFAULT;
2243         return ret;
2244 }
2245
2246 static noinline int btrfs_ioctl_tree_search_v2(struct file *file,
2247                                                void __user *argp)
2248 {
2249         struct btrfs_ioctl_search_args_v2 __user *uarg;
2250         struct btrfs_ioctl_search_args_v2 args;
2251         struct inode *inode;
2252         int ret;
2253         size_t buf_size;
2254         const size_t buf_limit = SZ_16M;
2255
2256         if (!capable(CAP_SYS_ADMIN))
2257                 return -EPERM;
2258
2259         /* copy search header and buffer size */
2260         uarg = (struct btrfs_ioctl_search_args_v2 __user *)argp;
2261         if (copy_from_user(&args, uarg, sizeof(args)))
2262                 return -EFAULT;
2263
2264         buf_size = args.buf_size;
2265
2266         /* limit result size to 16MB */
2267         if (buf_size > buf_limit)
2268                 buf_size = buf_limit;
2269
2270         inode = file_inode(file);
2271         ret = search_ioctl(inode, &args.key, &buf_size,
2272                            (char __user *)(&uarg->buf[0]));
2273         if (ret == 0 && copy_to_user(&uarg->key, &args.key, sizeof(args.key)))
2274                 ret = -EFAULT;
2275         else if (ret == -EOVERFLOW &&
2276                 copy_to_user(&uarg->buf_size, &buf_size, sizeof(buf_size)))
2277                 ret = -EFAULT;
2278
2279         return ret;
2280 }
2281
2282 /*
2283  * Search INODE_REFs to identify path name of 'dirid' directory
2284  * in a 'tree_id' tree. and sets path name to 'name'.
2285  */
2286 static noinline int btrfs_search_path_in_tree(struct btrfs_fs_info *info,
2287                                 u64 tree_id, u64 dirid, char *name)
2288 {
2289         struct btrfs_root *root;
2290         struct btrfs_key key;
2291         char *ptr;
2292         int ret = -1;
2293         int slot;
2294         int len;
2295         int total_len = 0;
2296         struct btrfs_inode_ref *iref;
2297         struct extent_buffer *l;
2298         struct btrfs_path *path;
2299
2300         if (dirid == BTRFS_FIRST_FREE_OBJECTID) {
2301                 name[0]='\0';
2302                 return 0;
2303         }
2304
2305         path = btrfs_alloc_path();
2306         if (!path)
2307                 return -ENOMEM;
2308
2309         ptr = &name[BTRFS_INO_LOOKUP_PATH_MAX - 1];
2310
2311         key.objectid = tree_id;
2312         key.type = BTRFS_ROOT_ITEM_KEY;
2313         key.offset = (u64)-1;
2314         root = btrfs_read_fs_root_no_name(info, &key);
2315         if (IS_ERR(root)) {
2316                 ret = PTR_ERR(root);
2317                 goto out;
2318         }
2319
2320         key.objectid = dirid;
2321         key.type = BTRFS_INODE_REF_KEY;
2322         key.offset = (u64)-1;
2323
2324         while (1) {
2325                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2326                 if (ret < 0)
2327                         goto out;
2328                 else if (ret > 0) {
2329                         ret = btrfs_previous_item(root, path, dirid,
2330                                                   BTRFS_INODE_REF_KEY);
2331                         if (ret < 0)
2332                                 goto out;
2333                         else if (ret > 0) {
2334                                 ret = -ENOENT;
2335                                 goto out;
2336                         }
2337                 }
2338
2339                 l = path->nodes[0];
2340                 slot = path->slots[0];
2341                 btrfs_item_key_to_cpu(l, &key, slot);
2342
2343                 iref = btrfs_item_ptr(l, slot, struct btrfs_inode_ref);
2344                 len = btrfs_inode_ref_name_len(l, iref);
2345                 ptr -= len + 1;
2346                 total_len += len + 1;
2347                 if (ptr < name) {
2348                         ret = -ENAMETOOLONG;
2349                         goto out;
2350                 }
2351
2352                 *(ptr + len) = '/';
2353                 read_extent_buffer(l, ptr, (unsigned long)(iref + 1), len);
2354
2355                 if (key.offset == BTRFS_FIRST_FREE_OBJECTID)
2356                         break;
2357
2358                 btrfs_release_path(path);
2359                 key.objectid = key.offset;
2360                 key.offset = (u64)-1;
2361                 dirid = key.objectid;
2362         }
2363         memmove(name, ptr, total_len);
2364         name[total_len] = '\0';
2365         ret = 0;
2366 out:
2367         btrfs_free_path(path);
2368         return ret;
2369 }
2370
2371 static int btrfs_search_path_in_tree_user(struct inode *inode,
2372                                 struct btrfs_ioctl_ino_lookup_user_args *args)
2373 {
2374         struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
2375         struct super_block *sb = inode->i_sb;
2376         struct btrfs_key upper_limit = BTRFS_I(inode)->location;
2377         u64 treeid = BTRFS_I(inode)->root->root_key.objectid;
2378         u64 dirid = args->dirid;
2379         unsigned long item_off;
2380         unsigned long item_len;
2381         struct btrfs_inode_ref *iref;
2382         struct btrfs_root_ref *rref;
2383         struct btrfs_root *root;
2384         struct btrfs_path *path;
2385         struct btrfs_key key, key2;
2386         struct extent_buffer *leaf;
2387         struct inode *temp_inode;
2388         char *ptr;
2389         int slot;
2390         int len;
2391         int total_len = 0;
2392         int ret;
2393
2394         path = btrfs_alloc_path();
2395         if (!path)
2396                 return -ENOMEM;
2397
2398         /*
2399          * If the bottom subvolume does not exist directly under upper_limit,
2400          * construct the path in from the bottom up.
2401          */
2402         if (dirid != upper_limit.objectid) {
2403                 ptr = &args->path[BTRFS_INO_LOOKUP_USER_PATH_MAX - 1];
2404
2405                 key.objectid = treeid;
2406                 key.type = BTRFS_ROOT_ITEM_KEY;
2407                 key.offset = (u64)-1;
2408                 root = btrfs_read_fs_root_no_name(fs_info, &key);
2409                 if (IS_ERR(root)) {
2410                         ret = PTR_ERR(root);
2411                         goto out;
2412                 }
2413
2414                 key.objectid = dirid;
2415                 key.type = BTRFS_INODE_REF_KEY;
2416                 key.offset = (u64)-1;
2417                 while (1) {
2418                         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2419                         if (ret < 0) {
2420                                 goto out;
2421                         } else if (ret > 0) {
2422                                 ret = btrfs_previous_item(root, path, dirid,
2423                                                           BTRFS_INODE_REF_KEY);
2424                                 if (ret < 0) {
2425                                         goto out;
2426                                 } else if (ret > 0) {
2427                                         ret = -ENOENT;
2428                                         goto out;
2429                                 }
2430                         }
2431
2432                         leaf = path->nodes[0];
2433                         slot = path->slots[0];
2434                         btrfs_item_key_to_cpu(leaf, &key, slot);
2435
2436                         iref = btrfs_item_ptr(leaf, slot, struct btrfs_inode_ref);
2437                         len = btrfs_inode_ref_name_len(leaf, iref);
2438                         ptr -= len + 1;
2439                         total_len += len + 1;
2440                         if (ptr < args->path) {
2441                                 ret = -ENAMETOOLONG;
2442                                 goto out;
2443                         }
2444
2445                         *(ptr + len) = '/';
2446                         read_extent_buffer(leaf, ptr,
2447                                         (unsigned long)(iref + 1), len);
2448
2449                         /* Check the read+exec permission of this directory */
2450                         ret = btrfs_previous_item(root, path, dirid,
2451                                                   BTRFS_INODE_ITEM_KEY);
2452                         if (ret < 0) {
2453                                 goto out;
2454                         } else if (ret > 0) {
2455                                 ret = -ENOENT;
2456                                 goto out;
2457                         }
2458
2459                         leaf = path->nodes[0];
2460                         slot = path->slots[0];
2461                         btrfs_item_key_to_cpu(leaf, &key2, slot);
2462                         if (key2.objectid != dirid) {
2463                                 ret = -ENOENT;
2464                                 goto out;
2465                         }
2466
2467                         temp_inode = btrfs_iget(sb, &key2, root, NULL);
2468                         if (IS_ERR(temp_inode)) {
2469                                 ret = PTR_ERR(temp_inode);
2470                                 goto out;
2471                         }
2472                         ret = inode_permission(temp_inode, MAY_READ | MAY_EXEC);
2473                         iput(temp_inode);
2474                         if (ret) {
2475                                 ret = -EACCES;
2476                                 goto out;
2477                         }
2478
2479                         if (key.offset == upper_limit.objectid)
2480                                 break;
2481                         if (key.objectid == BTRFS_FIRST_FREE_OBJECTID) {
2482                                 ret = -EACCES;
2483                                 goto out;
2484                         }
2485
2486                         btrfs_release_path(path);
2487                         key.objectid = key.offset;
2488                         key.offset = (u64)-1;
2489                         dirid = key.objectid;
2490                 }
2491
2492                 memmove(args->path, ptr, total_len);
2493                 args->path[total_len] = '\0';
2494                 btrfs_release_path(path);
2495         }
2496
2497         /* Get the bottom subvolume's name from ROOT_REF */
2498         root = fs_info->tree_root;
2499         key.objectid = treeid;
2500         key.type = BTRFS_ROOT_REF_KEY;
2501         key.offset = args->treeid;
2502         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2503         if (ret < 0) {
2504                 goto out;
2505         } else if (ret > 0) {
2506                 ret = -ENOENT;
2507                 goto out;
2508         }
2509
2510         leaf = path->nodes[0];
2511         slot = path->slots[0];
2512         btrfs_item_key_to_cpu(leaf, &key, slot);
2513
2514         item_off = btrfs_item_ptr_offset(leaf, slot);
2515         item_len = btrfs_item_size_nr(leaf, slot);
2516         /* Check if dirid in ROOT_REF corresponds to passed dirid */
2517         rref = btrfs_item_ptr(leaf, slot, struct btrfs_root_ref);
2518         if (args->dirid != btrfs_root_ref_dirid(leaf, rref)) {
2519                 ret = -EINVAL;
2520                 goto out;
2521         }
2522
2523         /* Copy subvolume's name */
2524         item_off += sizeof(struct btrfs_root_ref);
2525         item_len -= sizeof(struct btrfs_root_ref);
2526         read_extent_buffer(leaf, args->name, item_off, item_len);
2527         args->name[item_len] = 0;
2528
2529 out:
2530         btrfs_free_path(path);
2531         return ret;
2532 }
2533
2534 static noinline int btrfs_ioctl_ino_lookup(struct file *file,
2535                                            void __user *argp)
2536 {
2537         struct btrfs_ioctl_ino_lookup_args *args;
2538         struct inode *inode;
2539         int ret = 0;
2540
2541         args = memdup_user(argp, sizeof(*args));
2542         if (IS_ERR(args))
2543                 return PTR_ERR(args);
2544
2545         inode = file_inode(file);
2546
2547         /*
2548          * Unprivileged query to obtain the containing subvolume root id. The
2549          * path is reset so it's consistent with btrfs_search_path_in_tree.
2550          */
2551         if (args->treeid == 0)
2552                 args->treeid = BTRFS_I(inode)->root->root_key.objectid;
2553
2554         if (args->objectid == BTRFS_FIRST_FREE_OBJECTID) {
2555                 args->name[0] = 0;
2556                 goto out;
2557         }
2558
2559         if (!capable(CAP_SYS_ADMIN)) {
2560                 ret = -EPERM;
2561                 goto out;
2562         }
2563
2564         ret = btrfs_search_path_in_tree(BTRFS_I(inode)->root->fs_info,
2565                                         args->treeid, args->objectid,
2566                                         args->name);
2567
2568 out:
2569         if (ret == 0 && copy_to_user(argp, args, sizeof(*args)))
2570                 ret = -EFAULT;
2571
2572         kfree(args);
2573         return ret;
2574 }
2575
2576 /*
2577  * Version of ino_lookup ioctl (unprivileged)
2578  *
2579  * The main differences from ino_lookup ioctl are:
2580  *
2581  *   1. Read + Exec permission will be checked using inode_permission() during
2582  *      path construction. -EACCES will be returned in case of failure.
2583  *   2. Path construction will be stopped at the inode number which corresponds
2584  *      to the fd with which this ioctl is called. If constructed path does not
2585  *      exist under fd's inode, -EACCES will be returned.
2586  *   3. The name of bottom subvolume is also searched and filled.
2587  */
2588 static int btrfs_ioctl_ino_lookup_user(struct file *file, void __user *argp)
2589 {
2590         struct btrfs_ioctl_ino_lookup_user_args *args;
2591         struct inode *inode;
2592         int ret;
2593
2594         args = memdup_user(argp, sizeof(*args));
2595         if (IS_ERR(args))
2596                 return PTR_ERR(args);
2597
2598         inode = file_inode(file);
2599
2600         if (args->dirid == BTRFS_FIRST_FREE_OBJECTID &&
2601             BTRFS_I(inode)->location.objectid != BTRFS_FIRST_FREE_OBJECTID) {
2602                 /*
2603                  * The subvolume does not exist under fd with which this is
2604                  * called
2605                  */
2606                 kfree(args);
2607                 return -EACCES;
2608         }
2609
2610         ret = btrfs_search_path_in_tree_user(inode, args);
2611
2612         if (ret == 0 && copy_to_user(argp, args, sizeof(*args)))
2613                 ret = -EFAULT;
2614
2615         kfree(args);
2616         return ret;
2617 }
2618
2619 /* Get the subvolume information in BTRFS_ROOT_ITEM and BTRFS_ROOT_BACKREF */
2620 static int btrfs_ioctl_get_subvol_info(struct file *file, void __user *argp)
2621 {
2622         struct btrfs_ioctl_get_subvol_info_args *subvol_info;
2623         struct btrfs_fs_info *fs_info;
2624         struct btrfs_root *root;
2625         struct btrfs_path *path;
2626         struct btrfs_key key;
2627         struct btrfs_root_item *root_item;
2628         struct btrfs_root_ref *rref;
2629         struct extent_buffer *leaf;
2630         unsigned long item_off;
2631         unsigned long item_len;
2632         struct inode *inode;
2633         int slot;
2634         int ret = 0;
2635
2636         path = btrfs_alloc_path();
2637         if (!path)
2638                 return -ENOMEM;
2639
2640         subvol_info = kzalloc(sizeof(*subvol_info), GFP_KERNEL);
2641         if (!subvol_info) {
2642                 btrfs_free_path(path);
2643                 return -ENOMEM;
2644         }
2645
2646         inode = file_inode(file);
2647         fs_info = BTRFS_I(inode)->root->fs_info;
2648
2649         /* Get root_item of inode's subvolume */
2650         key.objectid = BTRFS_I(inode)->root->root_key.objectid;
2651         key.type = BTRFS_ROOT_ITEM_KEY;
2652         key.offset = (u64)-1;
2653         root = btrfs_read_fs_root_no_name(fs_info, &key);
2654         if (IS_ERR(root)) {
2655                 ret = PTR_ERR(root);
2656                 goto out;
2657         }
2658         root_item = &root->root_item;
2659
2660         subvol_info->treeid = key.objectid;
2661
2662         subvol_info->generation = btrfs_root_generation(root_item);
2663         subvol_info->flags = btrfs_root_flags(root_item);
2664
2665         memcpy(subvol_info->uuid, root_item->uuid, BTRFS_UUID_SIZE);
2666         memcpy(subvol_info->parent_uuid, root_item->parent_uuid,
2667                                                     BTRFS_UUID_SIZE);
2668         memcpy(subvol_info->received_uuid, root_item->received_uuid,
2669                                                     BTRFS_UUID_SIZE);
2670
2671         subvol_info->ctransid = btrfs_root_ctransid(root_item);
2672         subvol_info->ctime.sec = btrfs_stack_timespec_sec(&root_item->ctime);
2673         subvol_info->ctime.nsec = btrfs_stack_timespec_nsec(&root_item->ctime);
2674
2675         subvol_info->otransid = btrfs_root_otransid(root_item);
2676         subvol_info->otime.sec = btrfs_stack_timespec_sec(&root_item->otime);
2677         subvol_info->otime.nsec = btrfs_stack_timespec_nsec(&root_item->otime);
2678
2679         subvol_info->stransid = btrfs_root_stransid(root_item);
2680         subvol_info->stime.sec = btrfs_stack_timespec_sec(&root_item->stime);
2681         subvol_info->stime.nsec = btrfs_stack_timespec_nsec(&root_item->stime);
2682
2683         subvol_info->rtransid = btrfs_root_rtransid(root_item);
2684         subvol_info->rtime.sec = btrfs_stack_timespec_sec(&root_item->rtime);
2685         subvol_info->rtime.nsec = btrfs_stack_timespec_nsec(&root_item->rtime);
2686
2687         if (key.objectid != BTRFS_FS_TREE_OBJECTID) {
2688                 /* Search root tree for ROOT_BACKREF of this subvolume */
2689                 root = fs_info->tree_root;
2690
2691                 key.type = BTRFS_ROOT_BACKREF_KEY;
2692                 key.offset = 0;
2693                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2694                 if (ret < 0) {
2695                         goto out;
2696                 } else if (path->slots[0] >=
2697                            btrfs_header_nritems(path->nodes[0])) {
2698                         ret = btrfs_next_leaf(root, path);
2699                         if (ret < 0) {
2700                                 goto out;
2701                         } else if (ret > 0) {
2702                                 ret = -EUCLEAN;
2703                                 goto out;
2704                         }
2705                 }
2706
2707                 leaf = path->nodes[0];
2708                 slot = path->slots[0];
2709                 btrfs_item_key_to_cpu(leaf, &key, slot);
2710                 if (key.objectid == subvol_info->treeid &&
2711                     key.type == BTRFS_ROOT_BACKREF_KEY) {
2712                         subvol_info->parent_id = key.offset;
2713
2714                         rref = btrfs_item_ptr(leaf, slot, struct btrfs_root_ref);
2715                         subvol_info->dirid = btrfs_root_ref_dirid(leaf, rref);
2716
2717                         item_off = btrfs_item_ptr_offset(leaf, slot)
2718                                         + sizeof(struct btrfs_root_ref);
2719                         item_len = btrfs_item_size_nr(leaf, slot)
2720                                         - sizeof(struct btrfs_root_ref);
2721                         read_extent_buffer(leaf, subvol_info->name,
2722                                            item_off, item_len);
2723                 } else {
2724                         ret = -ENOENT;
2725                         goto out;
2726                 }
2727         }
2728
2729         if (copy_to_user(argp, subvol_info, sizeof(*subvol_info)))
2730                 ret = -EFAULT;
2731
2732 out:
2733         btrfs_free_path(path);
2734         kzfree(subvol_info);
2735         return ret;
2736 }
2737
2738 /*
2739  * Return ROOT_REF information of the subvolume containing this inode
2740  * except the subvolume name.
2741  */
2742 static int btrfs_ioctl_get_subvol_rootref(struct file *file, void __user *argp)
2743 {
2744         struct btrfs_ioctl_get_subvol_rootref_args *rootrefs;
2745         struct btrfs_root_ref *rref;
2746         struct btrfs_root *root;
2747         struct btrfs_path *path;
2748         struct btrfs_key key;
2749         struct extent_buffer *leaf;
2750         struct inode *inode;
2751         u64 objectid;
2752         int slot;
2753         int ret;
2754         u8 found;
2755
2756         path = btrfs_alloc_path();
2757         if (!path)
2758                 return -ENOMEM;
2759
2760         rootrefs = memdup_user(argp, sizeof(*rootrefs));
2761         if (IS_ERR(rootrefs)) {
2762                 btrfs_free_path(path);
2763                 return PTR_ERR(rootrefs);
2764         }
2765
2766         inode = file_inode(file);
2767         root = BTRFS_I(inode)->root->fs_info->tree_root;
2768         objectid = BTRFS_I(inode)->root->root_key.objectid;
2769
2770         key.objectid = objectid;
2771         key.type = BTRFS_ROOT_REF_KEY;
2772         key.offset = rootrefs->min_treeid;
2773         found = 0;
2774
2775         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2776         if (ret < 0) {
2777                 goto out;
2778         } else if (path->slots[0] >=
2779                    btrfs_header_nritems(path->nodes[0])) {
2780                 ret = btrfs_next_leaf(root, path);
2781                 if (ret < 0) {
2782                         goto out;
2783                 } else if (ret > 0) {
2784                         ret = -EUCLEAN;
2785                         goto out;
2786                 }
2787         }
2788         while (1) {
2789                 leaf = path->nodes[0];
2790                 slot = path->slots[0];
2791
2792                 btrfs_item_key_to_cpu(leaf, &key, slot);
2793                 if (key.objectid != objectid || key.type != BTRFS_ROOT_REF_KEY) {
2794                         ret = 0;
2795                         goto out;
2796                 }
2797
2798                 if (found == BTRFS_MAX_ROOTREF_BUFFER_NUM) {
2799                         ret = -EOVERFLOW;
2800                         goto out;
2801                 }
2802
2803                 rref = btrfs_item_ptr(leaf, slot, struct btrfs_root_ref);
2804                 rootrefs->rootref[found].treeid = key.offset;
2805                 rootrefs->rootref[found].dirid =
2806                                   btrfs_root_ref_dirid(leaf, rref);
2807                 found++;
2808
2809                 ret = btrfs_next_item(root, path);
2810                 if (ret < 0) {
2811                         goto out;
2812                 } else if (ret > 0) {
2813                         ret = -EUCLEAN;
2814                         goto out;
2815                 }
2816         }
2817
2818 out:
2819         if (!ret || ret == -EOVERFLOW) {
2820                 rootrefs->num_items = found;
2821                 /* update min_treeid for next search */
2822                 if (found)
2823                         rootrefs->min_treeid =
2824                                 rootrefs->rootref[found - 1].treeid + 1;
2825                 if (copy_to_user(argp, rootrefs, sizeof(*rootrefs)))
2826                         ret = -EFAULT;
2827         }
2828
2829         kfree(rootrefs);
2830         btrfs_free_path(path);
2831
2832         return ret;
2833 }
2834
2835 static noinline int btrfs_ioctl_snap_destroy(struct file *file,
2836                                              void __user *arg)
2837 {
2838         struct dentry *parent = file->f_path.dentry;
2839         struct btrfs_fs_info *fs_info = btrfs_sb(parent->d_sb);
2840         struct dentry *dentry;
2841         struct inode *dir = d_inode(parent);
2842         struct inode *inode;
2843         struct btrfs_root *root = BTRFS_I(dir)->root;
2844         struct btrfs_root *dest = NULL;
2845         struct btrfs_ioctl_vol_args *vol_args;
2846         int namelen;
2847         int err = 0;
2848
2849         if (!S_ISDIR(dir->i_mode))
2850                 return -ENOTDIR;
2851
2852         vol_args = memdup_user(arg, sizeof(*vol_args));
2853         if (IS_ERR(vol_args))
2854                 return PTR_ERR(vol_args);
2855
2856         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
2857         namelen = strlen(vol_args->name);
2858         if (strchr(vol_args->name, '/') ||
2859             strncmp(vol_args->name, "..", namelen) == 0) {
2860                 err = -EINVAL;
2861                 goto out;
2862         }
2863
2864         err = mnt_want_write_file(file);
2865         if (err)
2866                 goto out;
2867
2868
2869         err = down_write_killable_nested(&dir->i_rwsem, I_MUTEX_PARENT);
2870         if (err == -EINTR)
2871                 goto out_drop_write;
2872         dentry = lookup_one_len(vol_args->name, parent, namelen);
2873         if (IS_ERR(dentry)) {
2874                 err = PTR_ERR(dentry);
2875                 goto out_unlock_dir;
2876         }
2877
2878         if (d_really_is_negative(dentry)) {
2879                 err = -ENOENT;
2880                 goto out_dput;
2881         }
2882
2883         inode = d_inode(dentry);
2884         dest = BTRFS_I(inode)->root;
2885         if (!capable(CAP_SYS_ADMIN)) {
2886                 /*
2887                  * Regular user.  Only allow this with a special mount
2888                  * option, when the user has write+exec access to the
2889                  * subvol root, and when rmdir(2) would have been
2890                  * allowed.
2891                  *
2892                  * Note that this is _not_ check that the subvol is
2893                  * empty or doesn't contain data that we wouldn't
2894                  * otherwise be able to delete.
2895                  *
2896                  * Users who want to delete empty subvols should try
2897                  * rmdir(2).
2898                  */
2899                 err = -EPERM;
2900                 if (!btrfs_test_opt(fs_info, USER_SUBVOL_RM_ALLOWED))
2901                         goto out_dput;
2902
2903                 /*
2904                  * Do not allow deletion if the parent dir is the same
2905                  * as the dir to be deleted.  That means the ioctl
2906                  * must be called on the dentry referencing the root
2907                  * of the subvol, not a random directory contained
2908                  * within it.
2909                  */
2910                 err = -EINVAL;
2911                 if (root == dest)
2912                         goto out_dput;
2913
2914                 err = inode_permission(inode, MAY_WRITE | MAY_EXEC);
2915                 if (err)
2916                         goto out_dput;
2917         }
2918
2919         /* check if subvolume may be deleted by a user */
2920         err = btrfs_may_delete(dir, dentry, 1);
2921         if (err)
2922                 goto out_dput;
2923
2924         if (btrfs_ino(BTRFS_I(inode)) != BTRFS_FIRST_FREE_OBJECTID) {
2925                 err = -EINVAL;
2926                 goto out_dput;
2927         }
2928
2929         inode_lock(inode);
2930         err = btrfs_delete_subvolume(dir, dentry);
2931         inode_unlock(inode);
2932         if (!err) {
2933                 fsnotify_rmdir(dir, dentry);
2934                 d_delete(dentry);
2935         }
2936
2937 out_dput:
2938         dput(dentry);
2939 out_unlock_dir:
2940         inode_unlock(dir);
2941 out_drop_write:
2942         mnt_drop_write_file(file);
2943 out:
2944         kfree(vol_args);
2945         return err;
2946 }
2947
2948 static int btrfs_ioctl_defrag(struct file *file, void __user *argp)
2949 {
2950         struct inode *inode = file_inode(file);
2951         struct btrfs_root *root = BTRFS_I(inode)->root;
2952         struct btrfs_ioctl_defrag_range_args *range;
2953         int ret;
2954
2955         ret = mnt_want_write_file(file);
2956         if (ret)
2957                 return ret;
2958
2959         if (btrfs_root_readonly(root)) {
2960                 ret = -EROFS;
2961                 goto out;
2962         }
2963
2964         switch (inode->i_mode & S_IFMT) {
2965         case S_IFDIR:
2966                 if (!capable(CAP_SYS_ADMIN)) {
2967                         ret = -EPERM;
2968                         goto out;
2969                 }
2970                 ret = btrfs_defrag_root(root);
2971                 break;
2972         case S_IFREG:
2973                 /*
2974                  * Note that this does not check the file descriptor for write
2975                  * access. This prevents defragmenting executables that are
2976                  * running and allows defrag on files open in read-only mode.
2977                  */
2978                 if (!capable(CAP_SYS_ADMIN) &&
2979                     inode_permission(inode, MAY_WRITE)) {
2980                         ret = -EPERM;
2981                         goto out;
2982                 }
2983
2984                 range = kzalloc(sizeof(*range), GFP_KERNEL);
2985                 if (!range) {
2986                         ret = -ENOMEM;
2987                         goto out;
2988                 }
2989
2990                 if (argp) {
2991                         if (copy_from_user(range, argp,
2992                                            sizeof(*range))) {
2993                                 ret = -EFAULT;
2994                                 kfree(range);
2995                                 goto out;
2996                         }
2997                         /* compression requires us to start the IO */
2998                         if ((range->flags & BTRFS_DEFRAG_RANGE_COMPRESS)) {
2999                                 range->flags |= BTRFS_DEFRAG_RANGE_START_IO;
3000                                 range->extent_thresh = (u32)-1;
3001                         }
3002                 } else {
3003                         /* the rest are all set to zero by kzalloc */
3004                         range->len = (u64)-1;
3005                 }
3006                 ret = btrfs_defrag_file(file_inode(file), file,
3007                                         range, BTRFS_OLDEST_GENERATION, 0);
3008                 if (ret > 0)
3009                         ret = 0;
3010                 kfree(range);
3011                 break;
3012         default:
3013                 ret = -EINVAL;
3014         }
3015 out:
3016         mnt_drop_write_file(file);
3017         return ret;
3018 }
3019
3020 static long btrfs_ioctl_add_dev(struct btrfs_fs_info *fs_info, void __user *arg)
3021 {
3022         struct btrfs_ioctl_vol_args *vol_args;
3023         int ret;
3024
3025         if (!capable(CAP_SYS_ADMIN))
3026                 return -EPERM;
3027
3028         if (test_and_set_bit(BTRFS_FS_EXCL_OP, &fs_info->flags))
3029                 return BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
3030
3031         vol_args = memdup_user(arg, sizeof(*vol_args));
3032         if (IS_ERR(vol_args)) {
3033                 ret = PTR_ERR(vol_args);
3034                 goto out;
3035         }
3036
3037         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
3038         ret = btrfs_init_new_device(fs_info, vol_args->name);
3039
3040         if (!ret)
3041                 btrfs_info(fs_info, "disk added %s", vol_args->name);
3042
3043         kfree(vol_args);
3044 out:
3045         clear_bit(BTRFS_FS_EXCL_OP, &fs_info->flags);
3046         return ret;
3047 }
3048
3049 static long btrfs_ioctl_rm_dev_v2(struct file *file, void __user *arg)
3050 {
3051         struct inode *inode = file_inode(file);
3052         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3053         struct btrfs_ioctl_vol_args_v2 *vol_args;
3054         int ret;
3055
3056         if (!capable(CAP_SYS_ADMIN))
3057                 return -EPERM;
3058
3059         ret = mnt_want_write_file(file);
3060         if (ret)
3061                 return ret;
3062
3063         vol_args = memdup_user(arg, sizeof(*vol_args));
3064         if (IS_ERR(vol_args)) {
3065                 ret = PTR_ERR(vol_args);
3066                 goto err_drop;
3067         }
3068
3069         /* Check for compatibility reject unknown flags */
3070         if (vol_args->flags & ~BTRFS_VOL_ARG_V2_FLAGS_SUPPORTED) {
3071                 ret = -EOPNOTSUPP;
3072                 goto out;
3073         }
3074
3075         if (test_and_set_bit(BTRFS_FS_EXCL_OP, &fs_info->flags)) {
3076                 ret = BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
3077                 goto out;
3078         }
3079
3080         if (vol_args->flags & BTRFS_DEVICE_SPEC_BY_ID) {
3081                 ret = btrfs_rm_device(fs_info, NULL, vol_args->devid);
3082         } else {
3083                 vol_args->name[BTRFS_SUBVOL_NAME_MAX] = '\0';
3084                 ret = btrfs_rm_device(fs_info, vol_args->name, 0);
3085         }
3086         clear_bit(BTRFS_FS_EXCL_OP, &fs_info->flags);
3087
3088         if (!ret) {
3089                 if (vol_args->flags & BTRFS_DEVICE_SPEC_BY_ID)
3090                         btrfs_info(fs_info, "device deleted: id %llu",
3091                                         vol_args->devid);
3092                 else
3093                         btrfs_info(fs_info, "device deleted: %s",
3094                                         vol_args->name);
3095         }
3096 out:
3097         kfree(vol_args);
3098 err_drop:
3099         mnt_drop_write_file(file);
3100         return ret;
3101 }
3102
3103 static long btrfs_ioctl_rm_dev(struct file *file, void __user *arg)
3104 {
3105         struct inode *inode = file_inode(file);
3106         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3107         struct btrfs_ioctl_vol_args *vol_args;
3108         int ret;
3109
3110         if (!capable(CAP_SYS_ADMIN))
3111                 return -EPERM;
3112
3113         ret = mnt_want_write_file(file);
3114         if (ret)
3115                 return ret;
3116
3117         if (test_and_set_bit(BTRFS_FS_EXCL_OP, &fs_info->flags)) {
3118                 ret = BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
3119                 goto out_drop_write;
3120         }
3121
3122         vol_args = memdup_user(arg, sizeof(*vol_args));
3123         if (IS_ERR(vol_args)) {
3124                 ret = PTR_ERR(vol_args);
3125                 goto out;
3126         }
3127
3128         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
3129         ret = btrfs_rm_device(fs_info, vol_args->name, 0);
3130
3131         if (!ret)
3132                 btrfs_info(fs_info, "disk deleted %s", vol_args->name);
3133         kfree(vol_args);
3134 out:
3135         clear_bit(BTRFS_FS_EXCL_OP, &fs_info->flags);
3136 out_drop_write:
3137         mnt_drop_write_file(file);
3138
3139         return ret;
3140 }
3141
3142 static long btrfs_ioctl_fs_info(struct btrfs_fs_info *fs_info,
3143                                 void __user *arg)
3144 {
3145         struct btrfs_ioctl_fs_info_args *fi_args;
3146         struct btrfs_device *device;
3147         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
3148         int ret = 0;
3149
3150         fi_args = kzalloc(sizeof(*fi_args), GFP_KERNEL);
3151         if (!fi_args)
3152                 return -ENOMEM;
3153
3154         rcu_read_lock();
3155         fi_args->num_devices = fs_devices->num_devices;
3156
3157         list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
3158                 if (device->devid > fi_args->max_id)
3159                         fi_args->max_id = device->devid;
3160         }
3161         rcu_read_unlock();
3162
3163         memcpy(&fi_args->fsid, fs_devices->fsid, sizeof(fi_args->fsid));
3164         fi_args->nodesize = fs_info->nodesize;
3165         fi_args->sectorsize = fs_info->sectorsize;
3166         fi_args->clone_alignment = fs_info->sectorsize;
3167
3168         if (copy_to_user(arg, fi_args, sizeof(*fi_args)))
3169                 ret = -EFAULT;
3170
3171         kfree(fi_args);
3172         return ret;
3173 }
3174
3175 static long btrfs_ioctl_dev_info(struct btrfs_fs_info *fs_info,
3176                                  void __user *arg)
3177 {
3178         struct btrfs_ioctl_dev_info_args *di_args;
3179         struct btrfs_device *dev;
3180         int ret = 0;
3181         char *s_uuid = NULL;
3182
3183         di_args = memdup_user(arg, sizeof(*di_args));
3184         if (IS_ERR(di_args))
3185                 return PTR_ERR(di_args);
3186
3187         if (!btrfs_is_empty_uuid(di_args->uuid))
3188                 s_uuid = di_args->uuid;
3189
3190         rcu_read_lock();
3191         dev = btrfs_find_device(fs_info->fs_devices, di_args->devid, s_uuid,
3192                                 NULL, true);
3193
3194         if (!dev) {
3195                 ret = -ENODEV;
3196                 goto out;
3197         }
3198
3199         di_args->devid = dev->devid;
3200         di_args->bytes_used = btrfs_device_get_bytes_used(dev);
3201         di_args->total_bytes = btrfs_device_get_total_bytes(dev);
3202         memcpy(di_args->uuid, dev->uuid, sizeof(di_args->uuid));
3203         if (dev->name) {
3204                 strncpy(di_args->path, rcu_str_deref(dev->name),
3205                                 sizeof(di_args->path) - 1);
3206                 di_args->path[sizeof(di_args->path) - 1] = 0;
3207         } else {
3208                 di_args->path[0] = '\0';
3209         }
3210
3211 out:
3212         rcu_read_unlock();
3213         if (ret == 0 && copy_to_user(arg, di_args, sizeof(*di_args)))
3214                 ret = -EFAULT;
3215
3216         kfree(di_args);
3217         return ret;
3218 }
3219
3220 static void btrfs_double_extent_unlock(struct inode *inode1, u64 loff1,
3221                                        struct inode *inode2, u64 loff2, u64 len)
3222 {
3223         unlock_extent(&BTRFS_I(inode1)->io_tree, loff1, loff1 + len - 1);
3224         unlock_extent(&BTRFS_I(inode2)->io_tree, loff2, loff2 + len - 1);
3225 }
3226
3227 static void btrfs_double_extent_lock(struct inode *inode1, u64 loff1,
3228                                      struct inode *inode2, u64 loff2, u64 len)
3229 {
3230         if (inode1 < inode2) {
3231                 swap(inode1, inode2);
3232                 swap(loff1, loff2);
3233         } else if (inode1 == inode2 && loff2 < loff1) {
3234                 swap(loff1, loff2);
3235         }
3236         lock_extent(&BTRFS_I(inode1)->io_tree, loff1, loff1 + len - 1);
3237         lock_extent(&BTRFS_I(inode2)->io_tree, loff2, loff2 + len - 1);
3238 }
3239
3240 static int btrfs_extent_same_range(struct inode *src, u64 loff, u64 len,
3241                                    struct inode *dst, u64 dst_loff)
3242 {
3243         int ret;
3244
3245         /*
3246          * Lock destination range to serialize with concurrent readpages() and
3247          * source range to serialize with relocation.
3248          */
3249         btrfs_double_extent_lock(src, loff, dst, dst_loff, len);
3250         ret = btrfs_clone(src, dst, loff, len, len, dst_loff, 1);
3251         btrfs_double_extent_unlock(src, loff, dst, dst_loff, len);
3252
3253         return ret;
3254 }
3255
3256 #define BTRFS_MAX_DEDUPE_LEN    SZ_16M
3257
3258 static int btrfs_extent_same(struct inode *src, u64 loff, u64 olen,
3259                              struct inode *dst, u64 dst_loff)
3260 {
3261         int ret;
3262         u64 i, tail_len, chunk_count;
3263         struct btrfs_root *root_dst = BTRFS_I(dst)->root;
3264
3265         spin_lock(&root_dst->root_item_lock);
3266         if (root_dst->send_in_progress) {
3267                 btrfs_warn_rl(root_dst->fs_info,
3268 "cannot deduplicate to root %llu while send operations are using it (%d in progress)",
3269                               root_dst->root_key.objectid,
3270                               root_dst->send_in_progress);
3271                 spin_unlock(&root_dst->root_item_lock);
3272                 return -EAGAIN;
3273         }
3274         root_dst->dedupe_in_progress++;
3275         spin_unlock(&root_dst->root_item_lock);
3276
3277         tail_len = olen % BTRFS_MAX_DEDUPE_LEN;
3278         chunk_count = div_u64(olen, BTRFS_MAX_DEDUPE_LEN);
3279
3280         for (i = 0; i < chunk_count; i++) {
3281                 ret = btrfs_extent_same_range(src, loff, BTRFS_MAX_DEDUPE_LEN,
3282                                               dst, dst_loff);
3283                 if (ret)
3284                         goto out;
3285
3286                 loff += BTRFS_MAX_DEDUPE_LEN;
3287                 dst_loff += BTRFS_MAX_DEDUPE_LEN;
3288         }
3289
3290         if (tail_len > 0)
3291                 ret = btrfs_extent_same_range(src, loff, tail_len, dst,
3292                                               dst_loff);
3293 out:
3294         spin_lock(&root_dst->root_item_lock);
3295         root_dst->dedupe_in_progress--;
3296         spin_unlock(&root_dst->root_item_lock);
3297
3298         return ret;
3299 }
3300
3301 static int clone_finish_inode_update(struct btrfs_trans_handle *trans,
3302                                      struct inode *inode,
3303                                      u64 endoff,
3304                                      const u64 destoff,
3305                                      const u64 olen,
3306                                      int no_time_update)
3307 {
3308         struct btrfs_root *root = BTRFS_I(inode)->root;
3309         int ret;
3310
3311         inode_inc_iversion(inode);
3312         if (!no_time_update)
3313                 inode->i_mtime = inode->i_ctime = current_time(inode);
3314         /*
3315          * We round up to the block size at eof when determining which
3316          * extents to clone above, but shouldn't round up the file size.
3317          */
3318         if (endoff > destoff + olen)
3319                 endoff = destoff + olen;
3320         if (endoff > inode->i_size)
3321                 btrfs_i_size_write(BTRFS_I(inode), endoff);
3322
3323         ret = btrfs_update_inode(trans, root, inode);
3324         if (ret) {
3325                 btrfs_abort_transaction(trans, ret);
3326                 btrfs_end_transaction(trans);
3327                 goto out;
3328         }
3329         ret = btrfs_end_transaction(trans);
3330 out:
3331         return ret;
3332 }
3333
3334 /*
3335  * Make sure we do not end up inserting an inline extent into a file that has
3336  * already other (non-inline) extents. If a file has an inline extent it can
3337  * not have any other extents and the (single) inline extent must start at the
3338  * file offset 0. Failing to respect these rules will lead to file corruption,
3339  * resulting in EIO errors on read/write operations, hitting BUG_ON's in mm, etc
3340  *
3341  * We can have extents that have been already written to disk or we can have
3342  * dirty ranges still in delalloc, in which case the extent maps and items are
3343  * created only when we run delalloc, and the delalloc ranges might fall outside
3344  * the range we are currently locking in the inode's io tree. So we check the
3345  * inode's i_size because of that (i_size updates are done while holding the
3346  * i_mutex, which we are holding here).
3347  * We also check to see if the inode has a size not greater than "datal" but has
3348  * extents beyond it, due to an fallocate with FALLOC_FL_KEEP_SIZE (and we are
3349  * protected against such concurrent fallocate calls by the i_mutex).
3350  *
3351  * If the file has no extents but a size greater than datal, do not allow the
3352  * copy because we would need turn the inline extent into a non-inline one (even
3353  * with NO_HOLES enabled). If we find our destination inode only has one inline
3354  * extent, just overwrite it with the source inline extent if its size is less
3355  * than the source extent's size, or we could copy the source inline extent's
3356  * data into the destination inode's inline extent if the later is greater then
3357  * the former.
3358  */
3359 static int clone_copy_inline_extent(struct inode *dst,
3360                                     struct btrfs_trans_handle *trans,
3361                                     struct btrfs_path *path,
3362                                     struct btrfs_key *new_key,
3363                                     const u64 drop_start,
3364                                     const u64 datal,
3365                                     const u64 skip,
3366                                     const u64 size,
3367                                     char *inline_data)
3368 {
3369         struct btrfs_fs_info *fs_info = btrfs_sb(dst->i_sb);
3370         struct btrfs_root *root = BTRFS_I(dst)->root;
3371         const u64 aligned_end = ALIGN(new_key->offset + datal,
3372                                       fs_info->sectorsize);
3373         int ret;
3374         struct btrfs_key key;
3375
3376         if (new_key->offset > 0)
3377                 return -EOPNOTSUPP;
3378
3379         key.objectid = btrfs_ino(BTRFS_I(dst));
3380         key.type = BTRFS_EXTENT_DATA_KEY;
3381         key.offset = 0;
3382         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3383         if (ret < 0) {
3384                 return ret;
3385         } else if (ret > 0) {
3386                 if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {
3387                         ret = btrfs_next_leaf(root, path);
3388                         if (ret < 0)
3389                                 return ret;
3390                         else if (ret > 0)
3391                                 goto copy_inline_extent;
3392                 }
3393                 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
3394                 if (key.objectid == btrfs_ino(BTRFS_I(dst)) &&
3395                     key.type == BTRFS_EXTENT_DATA_KEY) {
3396                         ASSERT(key.offset > 0);
3397                         return -EOPNOTSUPP;
3398                 }
3399         } else if (i_size_read(dst) <= datal) {
3400                 struct btrfs_file_extent_item *ei;
3401                 u64 ext_len;
3402
3403                 /*
3404                  * If the file size is <= datal, make sure there are no other
3405                  * extents following (can happen do to an fallocate call with
3406                  * the flag FALLOC_FL_KEEP_SIZE).
3407                  */
3408                 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
3409                                     struct btrfs_file_extent_item);
3410                 /*
3411                  * If it's an inline extent, it can not have other extents
3412                  * following it.
3413                  */
3414                 if (btrfs_file_extent_type(path->nodes[0], ei) ==
3415                     BTRFS_FILE_EXTENT_INLINE)
3416                         goto copy_inline_extent;
3417
3418                 ext_len = btrfs_file_extent_num_bytes(path->nodes[0], ei);
3419                 if (ext_len > aligned_end)
3420                         return -EOPNOTSUPP;
3421
3422                 ret = btrfs_next_item(root, path);
3423                 if (ret < 0) {
3424                         return ret;
3425                 } else if (ret == 0) {
3426                         btrfs_item_key_to_cpu(path->nodes[0], &key,
3427                                               path->slots[0]);
3428                         if (key.objectid == btrfs_ino(BTRFS_I(dst)) &&
3429                             key.type == BTRFS_EXTENT_DATA_KEY)
3430                                 return -EOPNOTSUPP;
3431                 }
3432         }
3433
3434 copy_inline_extent:
3435         /*
3436          * We have no extent items, or we have an extent at offset 0 which may
3437          * or may not be inlined. All these cases are dealt the same way.
3438          */
3439         if (i_size_read(dst) > datal) {
3440                 /*
3441                  * If the destination inode has an inline extent...
3442                  * This would require copying the data from the source inline
3443                  * extent into the beginning of the destination's inline extent.
3444                  * But this is really complex, both extents can be compressed
3445                  * or just one of them, which would require decompressing and
3446                  * re-compressing data (which could increase the new compressed
3447                  * size, not allowing the compressed data to fit anymore in an
3448                  * inline extent).
3449                  * So just don't support this case for now (it should be rare,
3450                  * we are not really saving space when cloning inline extents).
3451                  */
3452                 return -EOPNOTSUPP;
3453         }
3454
3455         btrfs_release_path(path);
3456         ret = btrfs_drop_extents(trans, root, dst, drop_start, aligned_end, 1);
3457         if (ret)
3458                 return ret;
3459         ret = btrfs_insert_empty_item(trans, root, path, new_key, size);
3460         if (ret)
3461                 return ret;
3462
3463         if (skip) {
3464                 const u32 start = btrfs_file_extent_calc_inline_size(0);
3465
3466                 memmove(inline_data + start, inline_data + start + skip, datal);
3467         }
3468
3469         write_extent_buffer(path->nodes[0], inline_data,
3470                             btrfs_item_ptr_offset(path->nodes[0],
3471                                                   path->slots[0]),
3472                             size);
3473         inode_add_bytes(dst, datal);
3474         set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(dst)->runtime_flags);
3475
3476         return 0;
3477 }
3478
3479 /**
3480  * btrfs_clone() - clone a range from inode file to another
3481  *
3482  * @src: Inode to clone from
3483  * @inode: Inode to clone to
3484  * @off: Offset within source to start clone from
3485  * @olen: Original length, passed by user, of range to clone
3486  * @olen_aligned: Block-aligned value of olen
3487  * @destoff: Offset within @inode to start clone
3488  * @no_time_update: Whether to update mtime/ctime on the target inode
3489  */
3490 static int btrfs_clone(struct inode *src, struct inode *inode,
3491                        const u64 off, const u64 olen, const u64 olen_aligned,
3492                        const u64 destoff, int no_time_update)
3493 {
3494         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3495         struct btrfs_root *root = BTRFS_I(inode)->root;
3496         struct btrfs_path *path = NULL;
3497         struct extent_buffer *leaf;
3498         struct btrfs_trans_handle *trans;
3499         char *buf = NULL;
3500         struct btrfs_key key;
3501         u32 nritems;
3502         int slot;
3503         int ret;
3504         const u64 len = olen_aligned;
3505         u64 last_dest_end = destoff;
3506
3507         ret = -ENOMEM;
3508         buf = kvmalloc(fs_info->nodesize, GFP_KERNEL);
3509         if (!buf)
3510                 return ret;
3511
3512         path = btrfs_alloc_path();
3513         if (!path) {
3514                 kvfree(buf);
3515                 return ret;
3516         }
3517
3518         path->reada = READA_FORWARD;
3519         /* clone data */
3520         key.objectid = btrfs_ino(BTRFS_I(src));
3521         key.type = BTRFS_EXTENT_DATA_KEY;
3522         key.offset = off;
3523
3524         while (1) {
3525                 u64 next_key_min_offset = key.offset + 1;
3526                 struct btrfs_file_extent_item *extent;
3527                 int type;
3528                 u32 size;
3529                 struct btrfs_key new_key;
3530                 u64 disko = 0, diskl = 0;
3531                 u64 datao = 0, datal = 0;
3532                 u8 comp;
3533                 u64 drop_start;
3534
3535                 /*
3536                  * note the key will change type as we walk through the
3537                  * tree.
3538                  */
3539                 path->leave_spinning = 1;
3540                 ret = btrfs_search_slot(NULL, BTRFS_I(src)->root, &key, path,
3541                                 0, 0);
3542                 if (ret < 0)
3543                         goto out;
3544                 /*
3545                  * First search, if no extent item that starts at offset off was
3546                  * found but the previous item is an extent item, it's possible
3547                  * it might overlap our target range, therefore process it.
3548                  */
3549                 if (key.offset == off && ret > 0 && path->slots[0] > 0) {
3550                         btrfs_item_key_to_cpu(path->nodes[0], &key,
3551                                               path->slots[0] - 1);
3552                         if (key.type == BTRFS_EXTENT_DATA_KEY)
3553                                 path->slots[0]--;
3554                 }
3555
3556                 nritems = btrfs_header_nritems(path->nodes[0]);
3557 process_slot:
3558                 if (path->slots[0] >= nritems) {
3559                         ret = btrfs_next_leaf(BTRFS_I(src)->root, path);
3560                         if (ret < 0)
3561                                 goto out;
3562                         if (ret > 0)
3563                                 break;
3564                         nritems = btrfs_header_nritems(path->nodes[0]);
3565                 }
3566                 leaf = path->nodes[0];
3567                 slot = path->slots[0];
3568
3569                 btrfs_item_key_to_cpu(leaf, &key, slot);
3570                 if (key.type > BTRFS_EXTENT_DATA_KEY ||
3571                     key.objectid != btrfs_ino(BTRFS_I(src)))
3572                         break;
3573
3574                 ASSERT(key.type == BTRFS_EXTENT_DATA_KEY);
3575
3576                 extent = btrfs_item_ptr(leaf, slot,
3577                                         struct btrfs_file_extent_item);
3578                 comp = btrfs_file_extent_compression(leaf, extent);
3579                 type = btrfs_file_extent_type(leaf, extent);
3580                 if (type == BTRFS_FILE_EXTENT_REG ||
3581                     type == BTRFS_FILE_EXTENT_PREALLOC) {
3582                         disko = btrfs_file_extent_disk_bytenr(leaf, extent);
3583                         diskl = btrfs_file_extent_disk_num_bytes(leaf, extent);
3584                         datao = btrfs_file_extent_offset(leaf, extent);
3585                         datal = btrfs_file_extent_num_bytes(leaf, extent);
3586                 } else if (type == BTRFS_FILE_EXTENT_INLINE) {
3587                         /* Take upper bound, may be compressed */
3588                         datal = btrfs_file_extent_ram_bytes(leaf, extent);
3589                 }
3590
3591                 /*
3592                  * The first search might have left us at an extent item that
3593                  * ends before our target range's start, can happen if we have
3594                  * holes and NO_HOLES feature enabled.
3595                  */
3596                 if (key.offset + datal <= off) {
3597                         path->slots[0]++;
3598                         goto process_slot;
3599                 } else if (key.offset >= off + len) {
3600                         break;
3601                 }
3602                 next_key_min_offset = key.offset + datal;
3603                 size = btrfs_item_size_nr(leaf, slot);
3604                 read_extent_buffer(leaf, buf, btrfs_item_ptr_offset(leaf, slot),
3605                                    size);
3606
3607                 btrfs_release_path(path);
3608                 path->leave_spinning = 0;
3609
3610                 memcpy(&new_key, &key, sizeof(new_key));
3611                 new_key.objectid = btrfs_ino(BTRFS_I(inode));
3612                 if (off <= key.offset)
3613                         new_key.offset = key.offset + destoff - off;
3614                 else
3615                         new_key.offset = destoff;
3616
3617                 /*
3618                  * Deal with a hole that doesn't have an extent item that
3619                  * represents it (NO_HOLES feature enabled).
3620                  * This hole is either in the middle of the cloning range or at
3621                  * the beginning (fully overlaps it or partially overlaps it).
3622                  */
3623                 if (new_key.offset != last_dest_end)
3624                         drop_start = last_dest_end;
3625                 else
3626                         drop_start = new_key.offset;
3627
3628                 if (type == BTRFS_FILE_EXTENT_REG ||
3629                     type == BTRFS_FILE_EXTENT_PREALLOC) {
3630                         struct btrfs_clone_extent_info clone_info;
3631
3632                         /*
3633                          *    a  | --- range to clone ---|  b
3634                          * | ------------- extent ------------- |
3635                          */
3636
3637                         /* Subtract range b */
3638                         if (key.offset + datal > off + len)
3639                                 datal = off + len - key.offset;
3640
3641                         /* Subtract range a */
3642                         if (off > key.offset) {
3643                                 datao += off - key.offset;
3644                                 datal -= off - key.offset;
3645                         }
3646
3647                         clone_info.disk_offset = disko;
3648                         clone_info.disk_len = diskl;
3649                         clone_info.data_offset = datao;
3650                         clone_info.data_len = datal;
3651                         clone_info.file_offset = new_key.offset;
3652                         clone_info.extent_buf = buf;
3653                         clone_info.item_size = size;
3654                         ret = btrfs_punch_hole_range(inode, path,
3655                                                      drop_start,
3656                                                      new_key.offset + datal - 1,
3657                                                      &clone_info, &trans);
3658                         if (ret)
3659                                 goto out;
3660                 } else if (type == BTRFS_FILE_EXTENT_INLINE) {
3661                         u64 skip = 0;
3662                         u64 trim = 0;
3663
3664                         if (off > key.offset) {
3665                                 skip = off - key.offset;
3666                                 new_key.offset += skip;
3667                         }
3668
3669                         if (key.offset + datal > off + len)
3670                                 trim = key.offset + datal - (off + len);
3671
3672                         if (comp && (skip || trim)) {
3673                                 ret = -EINVAL;
3674                                 goto out;
3675                         }
3676                         size -= skip + trim;
3677                         datal -= skip + trim;
3678
3679                         /*
3680                          * If our extent is inline, we know we will drop or
3681                          * adjust at most 1 extent item in the destination root.
3682                          *
3683                          * 1 - adjusting old extent (we may have to split it)
3684                          * 1 - add new extent
3685                          * 1 - inode update
3686                          */
3687                         trans = btrfs_start_transaction(root, 3);
3688                         if (IS_ERR(trans)) {
3689                                 ret = PTR_ERR(trans);
3690                                 goto out;
3691                         }
3692
3693                         ret = clone_copy_inline_extent(inode, trans, path,
3694                                                        &new_key, drop_start,
3695                                                        datal, skip, size, buf);
3696                         if (ret) {
3697                                 if (ret != -EOPNOTSUPP)
3698                                         btrfs_abort_transaction(trans, ret);
3699                                 btrfs_end_transaction(trans);
3700                                 goto out;
3701                         }
3702                 }
3703
3704                 btrfs_release_path(path);
3705
3706                 last_dest_end = ALIGN(new_key.offset + datal,
3707                                       fs_info->sectorsize);
3708                 ret = clone_finish_inode_update(trans, inode, last_dest_end,
3709                                                 destoff, olen, no_time_update);
3710                 if (ret)
3711                         goto out;
3712                 if (new_key.offset + datal >= destoff + len)
3713                         break;
3714
3715                 btrfs_release_path(path);
3716                 key.offset = next_key_min_offset;
3717
3718                 if (fatal_signal_pending(current)) {
3719                         ret = -EINTR;
3720                         goto out;
3721                 }
3722         }
3723         ret = 0;
3724
3725         if (last_dest_end < destoff + len) {
3726                 struct btrfs_clone_extent_info clone_info = { 0 };
3727                 /*
3728                  * We have an implicit hole (NO_HOLES feature is enabled) that
3729                  * fully or partially overlaps our cloning range at its end.
3730                  */
3731                 btrfs_release_path(path);
3732                 path->leave_spinning = 0;
3733
3734                 /*
3735                  * We are dealing with a hole and our clone_info already has a
3736                  * disk_offset of 0, we only need to fill the data length and
3737                  * file offset.
3738                  */
3739                 clone_info.data_len = destoff + len - last_dest_end;
3740                 clone_info.file_offset = last_dest_end;
3741                 ret = btrfs_punch_hole_range(inode, path,
3742                                              last_dest_end, destoff + len - 1,
3743                                              &clone_info, &trans);
3744                 if (ret)
3745                         goto out;
3746
3747                 ret = clone_finish_inode_update(trans, inode, destoff + len,
3748                                                 destoff, olen, no_time_update);
3749         }
3750
3751 out:
3752         btrfs_free_path(path);
3753         kvfree(buf);
3754         return ret;
3755 }
3756
3757 static noinline int btrfs_clone_files(struct file *file, struct file *file_src,
3758                                         u64 off, u64 olen, u64 destoff)
3759 {
3760         struct inode *inode = file_inode(file);
3761         struct inode *src = file_inode(file_src);
3762         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3763         int ret;
3764         u64 len = olen;
3765         u64 bs = fs_info->sb->s_blocksize;
3766
3767         /*
3768          * TODO:
3769          * - split compressed inline extents.  annoying: we need to
3770          *   decompress into destination's address_space (the file offset
3771          *   may change, so source mapping won't do), then recompress (or
3772          *   otherwise reinsert) a subrange.
3773          *
3774          * - split destination inode's inline extents.  The inline extents can
3775          *   be either compressed or non-compressed.
3776          */
3777
3778         /*
3779          * VFS's generic_remap_file_range_prep() protects us from cloning the
3780          * eof block into the middle of a file, which would result in corruption
3781          * if the file size is not blocksize aligned. So we don't need to check
3782          * for that case here.
3783          */
3784         if (off + len == src->i_size)
3785                 len = ALIGN(src->i_size, bs) - off;
3786
3787         if (destoff > inode->i_size) {
3788                 const u64 wb_start = ALIGN_DOWN(inode->i_size, bs);
3789
3790                 ret = btrfs_cont_expand(inode, inode->i_size, destoff);
3791                 if (ret)
3792                         return ret;
3793                 /*
3794                  * We may have truncated the last block if the inode's size is
3795                  * not sector size aligned, so we need to wait for writeback to
3796                  * complete before proceeding further, otherwise we can race
3797                  * with cloning and attempt to increment a reference to an
3798                  * extent that no longer exists (writeback completed right after
3799                  * we found the previous extent covering eof and before we
3800                  * attempted to increment its reference count).
3801                  */
3802                 ret = btrfs_wait_ordered_range(inode, wb_start,
3803                                                destoff - wb_start);
3804                 if (ret)
3805                         return ret;
3806         }
3807
3808         /*
3809          * Lock destination range to serialize with concurrent readpages() and
3810          * source range to serialize with relocation.
3811          */
3812         btrfs_double_extent_lock(src, off, inode, destoff, len);
3813         ret = btrfs_clone(src, inode, off, olen, len, destoff, 0);
3814         btrfs_double_extent_unlock(src, off, inode, destoff, len);
3815         /*
3816          * Truncate page cache pages so that future reads will see the cloned
3817          * data immediately and not the previous data.
3818          */
3819         truncate_inode_pages_range(&inode->i_data,
3820                                 round_down(destoff, PAGE_SIZE),
3821                                 round_up(destoff + len, PAGE_SIZE) - 1);
3822
3823         return ret;
3824 }
3825
3826 static int btrfs_remap_file_range_prep(struct file *file_in, loff_t pos_in,
3827                                        struct file *file_out, loff_t pos_out,
3828                                        loff_t *len, unsigned int remap_flags)
3829 {
3830         struct inode *inode_in = file_inode(file_in);
3831         struct inode *inode_out = file_inode(file_out);
3832         u64 bs = BTRFS_I(inode_out)->root->fs_info->sb->s_blocksize;
3833         bool same_inode = inode_out == inode_in;
3834         u64 wb_len;
3835         int ret;
3836
3837         if (!(remap_flags & REMAP_FILE_DEDUP)) {
3838                 struct btrfs_root *root_out = BTRFS_I(inode_out)->root;
3839
3840                 if (btrfs_root_readonly(root_out))
3841                         return -EROFS;
3842
3843                 if (file_in->f_path.mnt != file_out->f_path.mnt ||
3844                     inode_in->i_sb != inode_out->i_sb)
3845                         return -EXDEV;
3846         }
3847
3848         /* don't make the dst file partly checksummed */
3849         if ((BTRFS_I(inode_in)->flags & BTRFS_INODE_NODATASUM) !=
3850             (BTRFS_I(inode_out)->flags & BTRFS_INODE_NODATASUM)) {
3851                 return -EINVAL;
3852         }
3853
3854         /*
3855          * Now that the inodes are locked, we need to start writeback ourselves
3856          * and can not rely on the writeback from the VFS's generic helper
3857          * generic_remap_file_range_prep() because:
3858          *
3859          * 1) For compression we must call filemap_fdatawrite_range() range
3860          *    twice (btrfs_fdatawrite_range() does it for us), and the generic
3861          *    helper only calls it once;
3862          *
3863          * 2) filemap_fdatawrite_range(), called by the generic helper only
3864          *    waits for the writeback to complete, i.e. for IO to be done, and
3865          *    not for the ordered extents to complete. We need to wait for them
3866          *    to complete so that new file extent items are in the fs tree.
3867          */
3868         if (*len == 0 && !(remap_flags & REMAP_FILE_DEDUP))
3869                 wb_len = ALIGN(inode_in->i_size, bs) - ALIGN_DOWN(pos_in, bs);
3870         else
3871                 wb_len = ALIGN(*len, bs);
3872
3873         /*
3874          * Since we don't lock ranges, wait for ongoing lockless dio writes (as
3875          * any in progress could create its ordered extents after we wait for
3876          * existing ordered extents below).
3877          */
3878         inode_dio_wait(inode_in);
3879         if (!same_inode)
3880                 inode_dio_wait(inode_out);
3881
3882         /*
3883          * Workaround to make sure NOCOW buffered write reach disk as NOCOW.
3884          *
3885          * Btrfs' back references do not have a block level granularity, they
3886          * work at the whole extent level.
3887          * NOCOW buffered write without data space reserved may not be able
3888          * to fall back to CoW due to lack of data space, thus could cause
3889          * data loss.
3890          *
3891          * Here we take a shortcut by flushing the whole inode, so that all
3892          * nocow write should reach disk as nocow before we increase the
3893          * reference of the extent. We could do better by only flushing NOCOW
3894          * data, but that needs extra accounting.
3895          *
3896          * Also we don't need to check ASYNC_EXTENT, as async extent will be
3897          * CoWed anyway, not affecting nocow part.
3898          */
3899         ret = filemap_flush(inode_in->i_mapping);
3900         if (ret < 0)
3901                 return ret;
3902
3903         ret = btrfs_wait_ordered_range(inode_in, ALIGN_DOWN(pos_in, bs),
3904                                        wb_len);
3905         if (ret < 0)
3906                 return ret;
3907         ret = btrfs_wait_ordered_range(inode_out, ALIGN_DOWN(pos_out, bs),
3908                                        wb_len);
3909         if (ret < 0)
3910                 return ret;
3911
3912         return generic_remap_file_range_prep(file_in, pos_in, file_out, pos_out,
3913                                             len, remap_flags);
3914 }
3915
3916 loff_t btrfs_remap_file_range(struct file *src_file, loff_t off,
3917                 struct file *dst_file, loff_t destoff, loff_t len,
3918                 unsigned int remap_flags)
3919 {
3920         struct inode *src_inode = file_inode(src_file);
3921         struct inode *dst_inode = file_inode(dst_file);
3922         bool same_inode = dst_inode == src_inode;
3923         int ret;
3924
3925         if (remap_flags & ~(REMAP_FILE_DEDUP | REMAP_FILE_ADVISORY))
3926                 return -EINVAL;
3927
3928         if (same_inode)
3929                 inode_lock(src_inode);
3930         else
3931                 lock_two_nondirectories(src_inode, dst_inode);
3932
3933         ret = btrfs_remap_file_range_prep(src_file, off, dst_file, destoff,
3934                                           &len, remap_flags);
3935         if (ret < 0 || len == 0)
3936                 goto out_unlock;
3937
3938         if (remap_flags & REMAP_FILE_DEDUP)
3939                 ret = btrfs_extent_same(src_inode, off, len, dst_inode, destoff);
3940         else
3941                 ret = btrfs_clone_files(dst_file, src_file, off, len, destoff);
3942
3943 out_unlock:
3944         if (same_inode)
3945                 inode_unlock(src_inode);
3946         else
3947                 unlock_two_nondirectories(src_inode, dst_inode);
3948
3949         return ret < 0 ? ret : len;
3950 }
3951
3952 static long btrfs_ioctl_default_subvol(struct file *file, void __user *argp)
3953 {
3954         struct inode *inode = file_inode(file);
3955         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3956         struct btrfs_root *root = BTRFS_I(inode)->root;
3957         struct btrfs_root *new_root;
3958         struct btrfs_dir_item *di;
3959         struct btrfs_trans_handle *trans;
3960         struct btrfs_path *path;
3961         struct btrfs_key location;
3962         struct btrfs_disk_key disk_key;
3963         u64 objectid = 0;
3964         u64 dir_id;
3965         int ret;
3966
3967         if (!capable(CAP_SYS_ADMIN))
3968                 return -EPERM;
3969
3970         ret = mnt_want_write_file(file);
3971         if (ret)
3972                 return ret;
3973
3974         if (copy_from_user(&objectid, argp, sizeof(objectid))) {
3975                 ret = -EFAULT;
3976                 goto out;
3977         }
3978
3979         if (!objectid)
3980                 objectid = BTRFS_FS_TREE_OBJECTID;
3981
3982         location.objectid = objectid;
3983         location.type = BTRFS_ROOT_ITEM_KEY;
3984         location.offset = (u64)-1;
3985
3986         new_root = btrfs_read_fs_root_no_name(fs_info, &location);
3987         if (IS_ERR(new_root)) {
3988                 ret = PTR_ERR(new_root);
3989                 goto out;
3990         }
3991         if (!is_fstree(new_root->root_key.objectid)) {
3992                 ret = -ENOENT;
3993                 goto out;
3994         }
3995
3996         path = btrfs_alloc_path();
3997         if (!path) {
3998                 ret = -ENOMEM;
3999                 goto out;
4000         }
4001         path->leave_spinning = 1;
4002
4003         trans = btrfs_start_transaction(root, 1);
4004         if (IS_ERR(trans)) {
4005                 btrfs_free_path(path);
4006                 ret = PTR_ERR(trans);
4007                 goto out;
4008         }
4009
4010         dir_id = btrfs_super_root_dir(fs_info->super_copy);
4011         di = btrfs_lookup_dir_item(trans, fs_info->tree_root, path,
4012                                    dir_id, "default", 7, 1);
4013         if (IS_ERR_OR_NULL(di)) {
4014                 btrfs_free_path(path);
4015                 btrfs_end_transaction(trans);
4016                 btrfs_err(fs_info,
4017                           "Umm, you don't have the default diritem, this isn't going to work");
4018                 ret = -ENOENT;
4019                 goto out;
4020         }
4021
4022         btrfs_cpu_key_to_disk(&disk_key, &new_root->root_key);
4023         btrfs_set_dir_item_key(path->nodes[0], di, &disk_key);
4024         btrfs_mark_buffer_dirty(path->nodes[0]);
4025         btrfs_free_path(path);
4026
4027         btrfs_set_fs_incompat(fs_info, DEFAULT_SUBVOL);
4028         btrfs_end_transaction(trans);
4029 out:
4030         mnt_drop_write_file(file);
4031         return ret;
4032 }
4033
4034 static void get_block_group_info(struct list_head *groups_list,
4035                                  struct btrfs_ioctl_space_info *space)
4036 {
4037         struct btrfs_block_group_cache *block_group;
4038
4039         space->total_bytes = 0;
4040         space->used_bytes = 0;
4041         space->flags = 0;
4042         list_for_each_entry(block_group, groups_list, list) {
4043                 space->flags = block_group->flags;
4044                 space->total_bytes += block_group->key.offset;
4045                 space->used_bytes +=
4046                         btrfs_block_group_used(&block_group->item);
4047         }
4048 }
4049
4050 static long btrfs_ioctl_space_info(struct btrfs_fs_info *fs_info,
4051                                    void __user *arg)
4052 {
4053         struct btrfs_ioctl_space_args space_args;
4054         struct btrfs_ioctl_space_info space;
4055         struct btrfs_ioctl_space_info *dest;
4056         struct btrfs_ioctl_space_info *dest_orig;
4057         struct btrfs_ioctl_space_info __user *user_dest;
4058         struct btrfs_space_info *info;
4059         static const u64 types[] = {
4060                 BTRFS_BLOCK_GROUP_DATA,
4061                 BTRFS_BLOCK_GROUP_SYSTEM,
4062                 BTRFS_BLOCK_GROUP_METADATA,
4063                 BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA
4064         };
4065         int num_types = 4;
4066         int alloc_size;
4067         int ret = 0;
4068         u64 slot_count = 0;
4069         int i, c;
4070
4071         if (copy_from_user(&space_args,
4072                            (struct btrfs_ioctl_space_args __user *)arg,
4073                            sizeof(space_args)))
4074                 return -EFAULT;
4075
4076         for (i = 0; i < num_types; i++) {
4077                 struct btrfs_space_info *tmp;
4078
4079                 info = NULL;
4080                 rcu_read_lock();
4081                 list_for_each_entry_rcu(tmp, &fs_info->space_info,
4082                                         list) {
4083                         if (tmp->flags == types[i]) {
4084                                 info = tmp;
4085                                 break;
4086                         }
4087                 }
4088                 rcu_read_unlock();
4089
4090                 if (!info)
4091                         continue;
4092
4093                 down_read(&info->groups_sem);
4094                 for (c = 0; c < BTRFS_NR_RAID_TYPES; c++) {
4095                         if (!list_empty(&info->block_groups[c]))
4096                                 slot_count++;
4097                 }
4098                 up_read(&info->groups_sem);
4099         }
4100
4101         /*
4102          * Global block reserve, exported as a space_info
4103          */
4104         slot_count++;
4105
4106         /* space_slots == 0 means they are asking for a count */
4107         if (space_args.space_slots == 0) {
4108                 space_args.total_spaces = slot_count;
4109                 goto out;
4110         }
4111
4112         slot_count = min_t(u64, space_args.space_slots, slot_count);
4113
4114         alloc_size = sizeof(*dest) * slot_count;
4115
4116         /* we generally have at most 6 or so space infos, one for each raid
4117          * level.  So, a whole page should be more than enough for everyone
4118          */
4119         if (alloc_size > PAGE_SIZE)
4120                 return -ENOMEM;
4121
4122         space_args.total_spaces = 0;
4123         dest = kmalloc(alloc_size, GFP_KERNEL);
4124         if (!dest)
4125                 return -ENOMEM;
4126         dest_orig = dest;
4127
4128         /* now we have a buffer to copy into */
4129         for (i = 0; i < num_types; i++) {
4130                 struct btrfs_space_info *tmp;
4131
4132                 if (!slot_count)
4133                         break;
4134
4135                 info = NULL;
4136                 rcu_read_lock();
4137                 list_for_each_entry_rcu(tmp, &fs_info->space_info,
4138                                         list) {
4139                         if (tmp->flags == types[i]) {
4140                                 info = tmp;
4141                                 break;
4142                         }
4143                 }
4144                 rcu_read_unlock();
4145
4146                 if (!info)
4147                         continue;
4148                 down_read(&info->groups_sem);
4149                 for (c = 0; c < BTRFS_NR_RAID_TYPES; c++) {
4150                         if (!list_empty(&info->block_groups[c])) {
4151                                 get_block_group_info(&info->block_groups[c],
4152                                                      &space);
4153                                 memcpy(dest, &space, sizeof(space));
4154                                 dest++;
4155                                 space_args.total_spaces++;
4156                                 slot_count--;
4157                         }
4158                         if (!slot_count)
4159                                 break;
4160                 }
4161                 up_read(&info->groups_sem);
4162         }
4163
4164         /*
4165          * Add global block reserve
4166          */
4167         if (slot_count) {
4168                 struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
4169
4170                 spin_lock(&block_rsv->lock);
4171                 space.total_bytes = block_rsv->size;
4172                 space.used_bytes = block_rsv->size - block_rsv->reserved;
4173                 spin_unlock(&block_rsv->lock);
4174                 space.flags = BTRFS_SPACE_INFO_GLOBAL_RSV;
4175                 memcpy(dest, &space, sizeof(space));
4176                 space_args.total_spaces++;
4177         }
4178
4179         user_dest = (struct btrfs_ioctl_space_info __user *)
4180                 (arg + sizeof(struct btrfs_ioctl_space_args));
4181
4182         if (copy_to_user(user_dest, dest_orig, alloc_size))
4183                 ret = -EFAULT;
4184
4185         kfree(dest_orig);
4186 out:
4187         if (ret == 0 && copy_to_user(arg, &space_args, sizeof(space_args)))
4188                 ret = -EFAULT;
4189
4190         return ret;
4191 }
4192
4193 static noinline long btrfs_ioctl_start_sync(struct btrfs_root *root,
4194                                             void __user *argp)
4195 {
4196         struct btrfs_trans_handle *trans;
4197         u64 transid;
4198         int ret;
4199
4200         btrfs_warn(root->fs_info,
4201         "START_SYNC ioctl is deprecated and will be removed in kernel 5.7");
4202
4203         trans = btrfs_attach_transaction_barrier(root);
4204         if (IS_ERR(trans)) {
4205                 if (PTR_ERR(trans) != -ENOENT)
4206                         return PTR_ERR(trans);
4207
4208                 /* No running transaction, don't bother */
4209                 transid = root->fs_info->last_trans_committed;
4210                 goto out;
4211         }
4212         transid = trans->transid;
4213         ret = btrfs_commit_transaction_async(trans, 0);
4214         if (ret) {
4215                 btrfs_end_transaction(trans);
4216                 return ret;
4217         }
4218 out:
4219         if (argp)
4220                 if (copy_to_user(argp, &transid, sizeof(transid)))
4221                         return -EFAULT;
4222         return 0;
4223 }
4224
4225 static noinline long btrfs_ioctl_wait_sync(struct btrfs_fs_info *fs_info,
4226                                            void __user *argp)
4227 {
4228         u64 transid;
4229
4230         btrfs_warn(fs_info,
4231                 "WAIT_SYNC ioctl is deprecated and will be removed in kernel 5.7");
4232
4233         if (argp) {
4234                 if (copy_from_user(&transid, argp, sizeof(transid)))
4235                         return -EFAULT;
4236         } else {
4237                 transid = 0;  /* current trans */
4238         }
4239         return btrfs_wait_for_commit(fs_info, transid);
4240 }
4241
4242 static long btrfs_ioctl_scrub(struct file *file, void __user *arg)
4243 {
4244         struct btrfs_fs_info *fs_info = btrfs_sb(file_inode(file)->i_sb);
4245         struct btrfs_ioctl_scrub_args *sa;
4246         int ret;
4247
4248         if (!capable(CAP_SYS_ADMIN))
4249                 return -EPERM;
4250
4251         sa = memdup_user(arg, sizeof(*sa));
4252         if (IS_ERR(sa))
4253                 return PTR_ERR(sa);
4254
4255         if (!(sa->flags & BTRFS_SCRUB_READONLY)) {
4256                 ret = mnt_want_write_file(file);
4257                 if (ret)
4258                         goto out;
4259         }
4260
4261         ret = btrfs_scrub_dev(fs_info, sa->devid, sa->start, sa->end,
4262                               &sa->progress, sa->flags & BTRFS_SCRUB_READONLY,
4263                               0);
4264
4265         if (ret == 0 && copy_to_user(arg, sa, sizeof(*sa)))
4266                 ret = -EFAULT;
4267
4268         if (!(sa->flags & BTRFS_SCRUB_READONLY))
4269                 mnt_drop_write_file(file);
4270 out:
4271         kfree(sa);
4272         return ret;
4273 }
4274
4275 static long btrfs_ioctl_scrub_cancel(struct btrfs_fs_info *fs_info)
4276 {
4277         if (!capable(CAP_SYS_ADMIN))
4278                 return -EPERM;
4279
4280         return btrfs_scrub_cancel(fs_info);
4281 }
4282
4283 static long btrfs_ioctl_scrub_progress(struct btrfs_fs_info *fs_info,
4284                                        void __user *arg)
4285 {
4286         struct btrfs_ioctl_scrub_args *sa;
4287         int ret;
4288
4289         if (!capable(CAP_SYS_ADMIN))
4290                 return -EPERM;
4291
4292         sa = memdup_user(arg, sizeof(*sa));
4293         if (IS_ERR(sa))
4294                 return PTR_ERR(sa);
4295
4296         ret = btrfs_scrub_progress(fs_info, sa->devid, &sa->progress);
4297
4298         if (ret == 0 && copy_to_user(arg, sa, sizeof(*sa)))
4299                 ret = -EFAULT;
4300
4301         kfree(sa);
4302         return ret;
4303 }
4304
4305 static long btrfs_ioctl_get_dev_stats(struct btrfs_fs_info *fs_info,
4306                                       void __user *arg)
4307 {
4308         struct btrfs_ioctl_get_dev_stats *sa;
4309         int ret;
4310
4311         sa = memdup_user(arg, sizeof(*sa));
4312         if (IS_ERR(sa))
4313                 return PTR_ERR(sa);
4314
4315         if ((sa->flags & BTRFS_DEV_STATS_RESET) && !capable(CAP_SYS_ADMIN)) {
4316                 kfree(sa);
4317                 return -EPERM;
4318         }
4319
4320         ret = btrfs_get_dev_stats(fs_info, sa);
4321
4322         if (ret == 0 && copy_to_user(arg, sa, sizeof(*sa)))
4323                 ret = -EFAULT;
4324
4325         kfree(sa);
4326         return ret;
4327 }
4328
4329 static long btrfs_ioctl_dev_replace(struct btrfs_fs_info *fs_info,
4330                                     void __user *arg)
4331 {
4332         struct btrfs_ioctl_dev_replace_args *p;
4333         int ret;
4334
4335         if (!capable(CAP_SYS_ADMIN))
4336                 return -EPERM;
4337
4338         p = memdup_user(arg, sizeof(*p));
4339         if (IS_ERR(p))
4340                 return PTR_ERR(p);
4341
4342         switch (p->cmd) {
4343         case BTRFS_IOCTL_DEV_REPLACE_CMD_START:
4344                 if (sb_rdonly(fs_info->sb)) {
4345                         ret = -EROFS;
4346                         goto out;
4347                 }
4348                 if (test_and_set_bit(BTRFS_FS_EXCL_OP, &fs_info->flags)) {
4349                         ret = BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
4350                 } else {
4351                         ret = btrfs_dev_replace_by_ioctl(fs_info, p);
4352                         clear_bit(BTRFS_FS_EXCL_OP, &fs_info->flags);
4353                 }
4354                 break;
4355         case BTRFS_IOCTL_DEV_REPLACE_CMD_STATUS:
4356                 btrfs_dev_replace_status(fs_info, p);
4357                 ret = 0;
4358                 break;
4359         case BTRFS_IOCTL_DEV_REPLACE_CMD_CANCEL:
4360                 p->result = btrfs_dev_replace_cancel(fs_info);
4361                 ret = 0;
4362                 break;
4363         default:
4364                 ret = -EINVAL;
4365                 break;
4366         }
4367
4368         if ((ret == 0 || ret == -ECANCELED) && copy_to_user(arg, p, sizeof(*p)))
4369                 ret = -EFAULT;
4370 out:
4371         kfree(p);
4372         return ret;
4373 }
4374
4375 static long btrfs_ioctl_ino_to_path(struct btrfs_root *root, void __user *arg)
4376 {
4377         int ret = 0;
4378         int i;
4379         u64 rel_ptr;
4380         int size;
4381         struct btrfs_ioctl_ino_path_args *ipa = NULL;
4382         struct inode_fs_paths *ipath = NULL;
4383         struct btrfs_path *path;
4384
4385         if (!capable(CAP_DAC_READ_SEARCH))
4386                 return -EPERM;
4387
4388         path = btrfs_alloc_path();
4389         if (!path) {
4390                 ret = -ENOMEM;
4391                 goto out;
4392         }
4393
4394         ipa = memdup_user(arg, sizeof(*ipa));
4395         if (IS_ERR(ipa)) {
4396                 ret = PTR_ERR(ipa);
4397                 ipa = NULL;
4398                 goto out;
4399         }
4400
4401         size = min_t(u32, ipa->size, 4096);
4402         ipath = init_ipath(size, root, path);
4403         if (IS_ERR(ipath)) {
4404                 ret = PTR_ERR(ipath);
4405                 ipath = NULL;
4406                 goto out;
4407         }
4408
4409         ret = paths_from_inode(ipa->inum, ipath);
4410         if (ret < 0)
4411                 goto out;
4412
4413         for (i = 0; i < ipath->fspath->elem_cnt; ++i) {
4414                 rel_ptr = ipath->fspath->val[i] -
4415                           (u64)(unsigned long)ipath->fspath->val;
4416                 ipath->fspath->val[i] = rel_ptr;
4417         }
4418
4419         ret = copy_to_user((void __user *)(unsigned long)ipa->fspath,
4420                            ipath->fspath, size);
4421         if (ret) {
4422                 ret = -EFAULT;
4423                 goto out;
4424         }
4425
4426 out:
4427         btrfs_free_path(path);
4428         free_ipath(ipath);
4429         kfree(ipa);
4430
4431         return ret;
4432 }
4433
4434 static int build_ino_list(u64 inum, u64 offset, u64 root, void *ctx)
4435 {
4436         struct btrfs_data_container *inodes = ctx;
4437         const size_t c = 3 * sizeof(u64);
4438
4439         if (inodes->bytes_left >= c) {
4440                 inodes->bytes_left -= c;
4441                 inodes->val[inodes->elem_cnt] = inum;
4442                 inodes->val[inodes->elem_cnt + 1] = offset;
4443                 inodes->val[inodes->elem_cnt + 2] = root;
4444                 inodes->elem_cnt += 3;
4445         } else {
4446                 inodes->bytes_missing += c - inodes->bytes_left;
4447                 inodes->bytes_left = 0;
4448                 inodes->elem_missed += 3;
4449         }
4450
4451         return 0;
4452 }
4453
4454 static long btrfs_ioctl_logical_to_ino(struct btrfs_fs_info *fs_info,
4455                                         void __user *arg, int version)
4456 {
4457         int ret = 0;
4458         int size;
4459         struct btrfs_ioctl_logical_ino_args *loi;
4460         struct btrfs_data_container *inodes = NULL;
4461         struct btrfs_path *path = NULL;
4462         bool ignore_offset;
4463
4464         if (!capable(CAP_SYS_ADMIN))
4465                 return -EPERM;
4466
4467         loi = memdup_user(arg, sizeof(*loi));
4468         if (IS_ERR(loi))
4469                 return PTR_ERR(loi);
4470
4471         if (version == 1) {
4472                 ignore_offset = false;
4473                 size = min_t(u32, loi->size, SZ_64K);
4474         } else {
4475                 /* All reserved bits must be 0 for now */
4476                 if (memchr_inv(loi->reserved, 0, sizeof(loi->reserved))) {
4477                         ret = -EINVAL;
4478                         goto out_loi;
4479                 }
4480                 /* Only accept flags we have defined so far */
4481                 if (loi->flags & ~(BTRFS_LOGICAL_INO_ARGS_IGNORE_OFFSET)) {
4482                         ret = -EINVAL;
4483                         goto out_loi;
4484                 }
4485                 ignore_offset = loi->flags & BTRFS_LOGICAL_INO_ARGS_IGNORE_OFFSET;
4486                 size = min_t(u32, loi->size, SZ_16M);
4487         }
4488
4489         path = btrfs_alloc_path();
4490         if (!path) {
4491                 ret = -ENOMEM;
4492                 goto out;
4493         }
4494
4495         inodes = init_data_container(size);
4496         if (IS_ERR(inodes)) {
4497                 ret = PTR_ERR(inodes);
4498                 inodes = NULL;
4499                 goto out;
4500         }
4501
4502         ret = iterate_inodes_from_logical(loi->logical, fs_info, path,
4503                                           build_ino_list, inodes, ignore_offset);
4504         if (ret == -EINVAL)
4505                 ret = -ENOENT;
4506         if (ret < 0)
4507                 goto out;
4508
4509         ret = copy_to_user((void __user *)(unsigned long)loi->inodes, inodes,
4510                            size);
4511         if (ret)
4512                 ret = -EFAULT;
4513
4514 out:
4515         btrfs_free_path(path);
4516         kvfree(inodes);
4517 out_loi:
4518         kfree(loi);
4519
4520         return ret;
4521 }
4522
4523 void btrfs_update_ioctl_balance_args(struct btrfs_fs_info *fs_info,
4524                                struct btrfs_ioctl_balance_args *bargs)
4525 {
4526         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
4527
4528         bargs->flags = bctl->flags;
4529
4530         if (test_bit(BTRFS_FS_BALANCE_RUNNING, &fs_info->flags))
4531                 bargs->state |= BTRFS_BALANCE_STATE_RUNNING;
4532         if (atomic_read(&fs_info->balance_pause_req))
4533                 bargs->state |= BTRFS_BALANCE_STATE_PAUSE_REQ;
4534         if (atomic_read(&fs_info->balance_cancel_req))
4535                 bargs->state |= BTRFS_BALANCE_STATE_CANCEL_REQ;
4536
4537         memcpy(&bargs->data, &bctl->data, sizeof(bargs->data));
4538         memcpy(&bargs->meta, &bctl->meta, sizeof(bargs->meta));
4539         memcpy(&bargs->sys, &bctl->sys, sizeof(bargs->sys));
4540
4541         spin_lock(&fs_info->balance_lock);
4542         memcpy(&bargs->stat, &bctl->stat, sizeof(bargs->stat));
4543         spin_unlock(&fs_info->balance_lock);
4544 }
4545
4546 static long btrfs_ioctl_balance(struct file *file, void __user *arg)
4547 {
4548         struct btrfs_root *root = BTRFS_I(file_inode(file))->root;
4549         struct btrfs_fs_info *fs_info = root->fs_info;
4550         struct btrfs_ioctl_balance_args *bargs;
4551         struct btrfs_balance_control *bctl;
4552         bool need_unlock; /* for mut. excl. ops lock */
4553         int ret;
4554
4555         if (!capable(CAP_SYS_ADMIN))
4556                 return -EPERM;
4557
4558         ret = mnt_want_write_file(file);
4559         if (ret)
4560                 return ret;
4561
4562 again:
4563         if (!test_and_set_bit(BTRFS_FS_EXCL_OP, &fs_info->flags)) {
4564                 mutex_lock(&fs_info->balance_mutex);
4565                 need_unlock = true;
4566                 goto locked;
4567         }
4568
4569         /*
4570          * mut. excl. ops lock is locked.  Three possibilities:
4571          *   (1) some other op is running
4572          *   (2) balance is running
4573          *   (3) balance is paused -- special case (think resume)
4574          */
4575         mutex_lock(&fs_info->balance_mutex);
4576         if (fs_info->balance_ctl) {
4577                 /* this is either (2) or (3) */
4578                 if (!test_bit(BTRFS_FS_BALANCE_RUNNING, &fs_info->flags)) {
4579                         mutex_unlock(&fs_info->balance_mutex);
4580                         /*
4581                          * Lock released to allow other waiters to continue,
4582                          * we'll reexamine the status again.
4583                          */
4584                         mutex_lock(&fs_info->balance_mutex);
4585
4586                         if (fs_info->balance_ctl &&
4587                             !test_bit(BTRFS_FS_BALANCE_RUNNING, &fs_info->flags)) {
4588                                 /* this is (3) */
4589                                 need_unlock = false;
4590                                 goto locked;
4591                         }
4592
4593                         mutex_unlock(&fs_info->balance_mutex);
4594                         goto again;
4595                 } else {
4596                         /* this is (2) */
4597                         mutex_unlock(&fs_info->balance_mutex);
4598                         ret = -EINPROGRESS;
4599                         goto out;
4600                 }
4601         } else {
4602                 /* this is (1) */
4603                 mutex_unlock(&fs_info->balance_mutex);
4604                 ret = BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
4605                 goto out;
4606         }
4607
4608 locked:
4609         BUG_ON(!test_bit(BTRFS_FS_EXCL_OP, &fs_info->flags));
4610
4611         if (arg) {
4612                 bargs = memdup_user(arg, sizeof(*bargs));
4613                 if (IS_ERR(bargs)) {
4614                         ret = PTR_ERR(bargs);
4615                         goto out_unlock;
4616                 }
4617
4618                 if (bargs->flags & BTRFS_BALANCE_RESUME) {
4619                         if (!fs_info->balance_ctl) {
4620                                 ret = -ENOTCONN;
4621                                 goto out_bargs;
4622                         }
4623
4624                         bctl = fs_info->balance_ctl;
4625                         spin_lock(&fs_info->balance_lock);
4626                         bctl->flags |= BTRFS_BALANCE_RESUME;
4627                         spin_unlock(&fs_info->balance_lock);
4628
4629                         goto do_balance;
4630                 }
4631         } else {
4632                 bargs = NULL;
4633         }
4634
4635         if (fs_info->balance_ctl) {
4636                 ret = -EINPROGRESS;
4637                 goto out_bargs;
4638         }
4639
4640         bctl = kzalloc(sizeof(*bctl), GFP_KERNEL);
4641         if (!bctl) {
4642                 ret = -ENOMEM;
4643                 goto out_bargs;
4644         }
4645
4646         if (arg) {
4647                 memcpy(&bctl->data, &bargs->data, sizeof(bctl->data));
4648                 memcpy(&bctl->meta, &bargs->meta, sizeof(bctl->meta));
4649                 memcpy(&bctl->sys, &bargs->sys, sizeof(bctl->sys));
4650
4651                 bctl->flags = bargs->flags;
4652         } else {
4653                 /* balance everything - no filters */
4654                 bctl->flags |= BTRFS_BALANCE_TYPE_MASK;
4655         }
4656
4657         if (bctl->flags & ~(BTRFS_BALANCE_ARGS_MASK | BTRFS_BALANCE_TYPE_MASK)) {
4658                 ret = -EINVAL;
4659                 goto out_bctl;
4660         }
4661
4662 do_balance:
4663         /*
4664          * Ownership of bctl and filesystem flag BTRFS_FS_EXCL_OP goes to
4665          * btrfs_balance.  bctl is freed in reset_balance_state, or, if
4666          * restriper was paused all the way until unmount, in free_fs_info.
4667          * The flag should be cleared after reset_balance_state.
4668          */
4669         need_unlock = false;
4670
4671         ret = btrfs_balance(fs_info, bctl, bargs);
4672         bctl = NULL;
4673
4674         if ((ret == 0 || ret == -ECANCELED) && arg) {
4675                 if (copy_to_user(arg, bargs, sizeof(*bargs)))
4676                         ret = -EFAULT;
4677         }
4678
4679 out_bctl:
4680         kfree(bctl);
4681 out_bargs:
4682         kfree(bargs);
4683 out_unlock:
4684         mutex_unlock(&fs_info->balance_mutex);
4685         if (need_unlock)
4686                 clear_bit(BTRFS_FS_EXCL_OP, &fs_info->flags);
4687 out:
4688         mnt_drop_write_file(file);
4689         return ret;
4690 }
4691
4692 static long btrfs_ioctl_balance_ctl(struct btrfs_fs_info *fs_info, int cmd)
4693 {
4694         if (!capable(CAP_SYS_ADMIN))
4695                 return -EPERM;
4696
4697         switch (cmd) {
4698         case BTRFS_BALANCE_CTL_PAUSE:
4699                 return btrfs_pause_balance(fs_info);
4700         case BTRFS_BALANCE_CTL_CANCEL:
4701                 return btrfs_cancel_balance(fs_info);
4702         }
4703
4704         return -EINVAL;
4705 }
4706
4707 static long btrfs_ioctl_balance_progress(struct btrfs_fs_info *fs_info,
4708                                          void __user *arg)
4709 {
4710         struct btrfs_ioctl_balance_args *bargs;
4711         int ret = 0;
4712
4713         if (!capable(CAP_SYS_ADMIN))
4714                 return -EPERM;
4715
4716         mutex_lock(&fs_info->balance_mutex);
4717         if (!fs_info->balance_ctl) {
4718                 ret = -ENOTCONN;
4719                 goto out;
4720         }
4721
4722         bargs = kzalloc(sizeof(*bargs), GFP_KERNEL);
4723         if (!bargs) {
4724                 ret = -ENOMEM;
4725                 goto out;
4726         }
4727
4728         btrfs_update_ioctl_balance_args(fs_info, bargs);
4729
4730         if (copy_to_user(arg, bargs, sizeof(*bargs)))
4731                 ret = -EFAULT;
4732
4733         kfree(bargs);
4734 out:
4735         mutex_unlock(&fs_info->balance_mutex);
4736         return ret;
4737 }
4738
4739 static long btrfs_ioctl_quota_ctl(struct file *file, void __user *arg)
4740 {
4741         struct inode *inode = file_inode(file);
4742         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4743         struct btrfs_ioctl_quota_ctl_args *sa;
4744         int ret;
4745
4746         if (!capable(CAP_SYS_ADMIN))
4747                 return -EPERM;
4748
4749         ret = mnt_want_write_file(file);
4750         if (ret)
4751                 return ret;
4752
4753         sa = memdup_user(arg, sizeof(*sa));
4754         if (IS_ERR(sa)) {
4755                 ret = PTR_ERR(sa);
4756                 goto drop_write;
4757         }
4758
4759         down_write(&fs_info->subvol_sem);
4760
4761         switch (sa->cmd) {
4762         case BTRFS_QUOTA_CTL_ENABLE:
4763                 ret = btrfs_quota_enable(fs_info);
4764                 break;
4765         case BTRFS_QUOTA_CTL_DISABLE:
4766                 ret = btrfs_quota_disable(fs_info);
4767                 break;
4768         default:
4769                 ret = -EINVAL;
4770                 break;
4771         }
4772
4773         kfree(sa);
4774         up_write(&fs_info->subvol_sem);
4775 drop_write:
4776         mnt_drop_write_file(file);
4777         return ret;
4778 }
4779
4780 static long btrfs_ioctl_qgroup_assign(struct file *file, void __user *arg)
4781 {
4782         struct inode *inode = file_inode(file);
4783         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4784         struct btrfs_root *root = BTRFS_I(inode)->root;
4785         struct btrfs_ioctl_qgroup_assign_args *sa;
4786         struct btrfs_trans_handle *trans;
4787         int ret;
4788         int err;
4789
4790         if (!capable(CAP_SYS_ADMIN))
4791                 return -EPERM;
4792
4793         ret = mnt_want_write_file(file);
4794         if (ret)
4795                 return ret;
4796
4797         sa = memdup_user(arg, sizeof(*sa));
4798         if (IS_ERR(sa)) {
4799                 ret = PTR_ERR(sa);
4800                 goto drop_write;
4801         }
4802
4803         trans = btrfs_join_transaction(root);
4804         if (IS_ERR(trans)) {
4805                 ret = PTR_ERR(trans);
4806                 goto out;
4807         }
4808
4809         if (sa->assign) {
4810                 ret = btrfs_add_qgroup_relation(trans, sa->src, sa->dst);
4811         } else {
4812                 ret = btrfs_del_qgroup_relation(trans, sa->src, sa->dst);
4813         }
4814
4815         /* update qgroup status and info */
4816         err = btrfs_run_qgroups(trans);
4817         if (err < 0)
4818                 btrfs_handle_fs_error(fs_info, err,
4819                                       "failed to update qgroup status and info");
4820         err = btrfs_end_transaction(trans);
4821         if (err && !ret)
4822                 ret = err;
4823
4824 out:
4825         kfree(sa);
4826 drop_write:
4827         mnt_drop_write_file(file);
4828         return ret;
4829 }
4830
4831 static long btrfs_ioctl_qgroup_create(struct file *file, void __user *arg)
4832 {
4833         struct inode *inode = file_inode(file);
4834         struct btrfs_root *root = BTRFS_I(inode)->root;
4835         struct btrfs_ioctl_qgroup_create_args *sa;
4836         struct btrfs_trans_handle *trans;
4837         int ret;
4838         int err;
4839
4840         if (!capable(CAP_SYS_ADMIN))
4841                 return -EPERM;
4842
4843         ret = mnt_want_write_file(file);
4844         if (ret)
4845                 return ret;
4846
4847         sa = memdup_user(arg, sizeof(*sa));
4848         if (IS_ERR(sa)) {
4849                 ret = PTR_ERR(sa);
4850                 goto drop_write;
4851         }
4852
4853         if (!sa->qgroupid) {
4854                 ret = -EINVAL;
4855                 goto out;
4856         }
4857
4858         trans = btrfs_join_transaction(root);
4859         if (IS_ERR(trans)) {
4860                 ret = PTR_ERR(trans);
4861                 goto out;
4862         }
4863
4864         if (sa->create) {
4865                 ret = btrfs_create_qgroup(trans, sa->qgroupid);
4866         } else {
4867                 ret = btrfs_remove_qgroup(trans, sa->qgroupid);
4868         }
4869
4870         err = btrfs_end_transaction(trans);
4871         if (err && !ret)
4872                 ret = err;
4873
4874 out:
4875         kfree(sa);
4876 drop_write:
4877         mnt_drop_write_file(file);
4878         return ret;
4879 }
4880
4881 static long btrfs_ioctl_qgroup_limit(struct file *file, void __user *arg)
4882 {
4883         struct inode *inode = file_inode(file);
4884         struct btrfs_root *root = BTRFS_I(inode)->root;
4885         struct btrfs_ioctl_qgroup_limit_args *sa;
4886         struct btrfs_trans_handle *trans;
4887         int ret;
4888         int err;
4889         u64 qgroupid;
4890
4891         if (!capable(CAP_SYS_ADMIN))
4892                 return -EPERM;
4893
4894         ret = mnt_want_write_file(file);
4895         if (ret)
4896                 return ret;
4897
4898         sa = memdup_user(arg, sizeof(*sa));
4899         if (IS_ERR(sa)) {
4900                 ret = PTR_ERR(sa);
4901                 goto drop_write;
4902         }
4903
4904         trans = btrfs_join_transaction(root);
4905         if (IS_ERR(trans)) {
4906                 ret = PTR_ERR(trans);
4907                 goto out;
4908         }
4909
4910         qgroupid = sa->qgroupid;
4911         if (!qgroupid) {
4912                 /* take the current subvol as qgroup */
4913                 qgroupid = root->root_key.objectid;
4914         }
4915
4916         ret = btrfs_limit_qgroup(trans, qgroupid, &sa->lim);
4917
4918         err = btrfs_end_transaction(trans);
4919         if (err && !ret)
4920                 ret = err;
4921
4922 out:
4923         kfree(sa);
4924 drop_write:
4925         mnt_drop_write_file(file);
4926         return ret;
4927 }
4928
4929 static long btrfs_ioctl_quota_rescan(struct file *file, void __user *arg)
4930 {
4931         struct inode *inode = file_inode(file);
4932         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4933         struct btrfs_ioctl_quota_rescan_args *qsa;
4934         int ret;
4935
4936         if (!capable(CAP_SYS_ADMIN))
4937                 return -EPERM;
4938
4939         ret = mnt_want_write_file(file);
4940         if (ret)
4941                 return ret;
4942
4943         qsa = memdup_user(arg, sizeof(*qsa));
4944         if (IS_ERR(qsa)) {
4945                 ret = PTR_ERR(qsa);
4946                 goto drop_write;
4947         }
4948
4949         if (qsa->flags) {
4950                 ret = -EINVAL;
4951                 goto out;
4952         }
4953
4954         ret = btrfs_qgroup_rescan(fs_info);
4955
4956 out:
4957         kfree(qsa);
4958 drop_write:
4959         mnt_drop_write_file(file);
4960         return ret;
4961 }
4962
4963 static long btrfs_ioctl_quota_rescan_status(struct file *file, void __user *arg)
4964 {
4965         struct inode *inode = file_inode(file);
4966         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4967         struct btrfs_ioctl_quota_rescan_args *qsa;
4968         int ret = 0;
4969
4970         if (!capable(CAP_SYS_ADMIN))
4971                 return -EPERM;
4972
4973         qsa = kzalloc(sizeof(*qsa), GFP_KERNEL);
4974         if (!qsa)
4975                 return -ENOMEM;
4976
4977         if (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN) {
4978                 qsa->flags = 1;
4979                 qsa->progress = fs_info->qgroup_rescan_progress.objectid;
4980         }
4981
4982         if (copy_to_user(arg, qsa, sizeof(*qsa)))
4983                 ret = -EFAULT;
4984
4985         kfree(qsa);
4986         return ret;
4987 }
4988
4989 static long btrfs_ioctl_quota_rescan_wait(struct file *file, void __user *arg)
4990 {
4991         struct inode *inode = file_inode(file);
4992         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4993
4994         if (!capable(CAP_SYS_ADMIN))
4995                 return -EPERM;
4996
4997         return btrfs_qgroup_wait_for_completion(fs_info, true);
4998 }
4999
5000 static long _btrfs_ioctl_set_received_subvol(struct file *file,
5001                                             struct btrfs_ioctl_received_subvol_args *sa)
5002 {
5003         struct inode *inode = file_inode(file);
5004         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
5005         struct btrfs_root *root = BTRFS_I(inode)->root;
5006         struct btrfs_root_item *root_item = &root->root_item;
5007         struct btrfs_trans_handle *trans;
5008         struct timespec64 ct = current_time(inode);
5009         int ret = 0;
5010         int received_uuid_changed;
5011
5012         if (!inode_owner_or_capable(inode))
5013                 return -EPERM;
5014
5015         ret = mnt_want_write_file(file);
5016         if (ret < 0)
5017                 return ret;
5018
5019         down_write(&fs_info->subvol_sem);
5020
5021         if (btrfs_ino(BTRFS_I(inode)) != BTRFS_FIRST_FREE_OBJECTID) {
5022                 ret = -EINVAL;
5023                 goto out;
5024         }
5025
5026         if (btrfs_root_readonly(root)) {
5027                 ret = -EROFS;
5028                 goto out;
5029         }
5030
5031         /*
5032          * 1 - root item
5033          * 2 - uuid items (received uuid + subvol uuid)
5034          */
5035         trans = btrfs_start_transaction(root, 3);
5036         if (IS_ERR(trans)) {
5037                 ret = PTR_ERR(trans);
5038                 trans = NULL;
5039                 goto out;
5040         }
5041
5042         sa->rtransid = trans->transid;
5043         sa->rtime.sec = ct.tv_sec;
5044         sa->rtime.nsec = ct.tv_nsec;
5045
5046         received_uuid_changed = memcmp(root_item->received_uuid, sa->uuid,
5047                                        BTRFS_UUID_SIZE);
5048         if (received_uuid_changed &&
5049             !btrfs_is_empty_uuid(root_item->received_uuid)) {
5050                 ret = btrfs_uuid_tree_remove(trans, root_item->received_uuid,
5051                                           BTRFS_UUID_KEY_RECEIVED_SUBVOL,
5052                                           root->root_key.objectid);
5053                 if (ret && ret != -ENOENT) {
5054                         btrfs_abort_transaction(trans, ret);
5055                         btrfs_end_transaction(trans);
5056                         goto out;
5057                 }
5058         }
5059         memcpy(root_item->received_uuid, sa->uuid, BTRFS_UUID_SIZE);
5060         btrfs_set_root_stransid(root_item, sa->stransid);
5061         btrfs_set_root_rtransid(root_item, sa->rtransid);
5062         btrfs_set_stack_timespec_sec(&root_item->stime, sa->stime.sec);
5063         btrfs_set_stack_timespec_nsec(&root_item->stime, sa->stime.nsec);
5064         btrfs_set_stack_timespec_sec(&root_item->rtime, sa->rtime.sec);
5065         btrfs_set_stack_timespec_nsec(&root_item->rtime, sa->rtime.nsec);
5066
5067         ret = btrfs_update_root(trans, fs_info->tree_root,
5068                                 &root->root_key, &root->root_item);
5069         if (ret < 0) {
5070                 btrfs_end_transaction(trans);
5071                 goto out;
5072         }
5073         if (received_uuid_changed && !btrfs_is_empty_uuid(sa->uuid)) {
5074                 ret = btrfs_uuid_tree_add(trans, sa->uuid,
5075                                           BTRFS_UUID_KEY_RECEIVED_SUBVOL,
5076                                           root->root_key.objectid);
5077                 if (ret < 0 && ret != -EEXIST) {
5078                         btrfs_abort_transaction(trans, ret);
5079                         btrfs_end_transaction(trans);
5080                         goto out;
5081                 }
5082         }
5083         ret = btrfs_commit_transaction(trans);
5084 out:
5085         up_write(&fs_info->subvol_sem);
5086         mnt_drop_write_file(file);
5087         return ret;
5088 }
5089
5090 #ifdef CONFIG_64BIT
5091 static long btrfs_ioctl_set_received_subvol_32(struct file *file,
5092                                                 void __user *arg)
5093 {
5094         struct btrfs_ioctl_received_subvol_args_32 *args32 = NULL;
5095         struct btrfs_ioctl_received_subvol_args *args64 = NULL;
5096         int ret = 0;
5097
5098         args32 = memdup_user(arg, sizeof(*args32));
5099         if (IS_ERR(args32))
5100                 return PTR_ERR(args32);
5101
5102         args64 = kmalloc(sizeof(*args64), GFP_KERNEL);
5103         if (!args64) {
5104                 ret = -ENOMEM;
5105                 goto out;
5106         }
5107
5108         memcpy(args64->uuid, args32->uuid, BTRFS_UUID_SIZE);
5109         args64->stransid = args32->stransid;
5110         args64->rtransid = args32->rtransid;
5111         args64->stime.sec = args32->stime.sec;
5112         args64->stime.nsec = args32->stime.nsec;
5113         args64->rtime.sec = args32->rtime.sec;
5114         args64->rtime.nsec = args32->rtime.nsec;
5115         args64->flags = args32->flags;
5116
5117         ret = _btrfs_ioctl_set_received_subvol(file, args64);
5118         if (ret)
5119                 goto out;
5120
5121         memcpy(args32->uuid, args64->uuid, BTRFS_UUID_SIZE);
5122         args32->stransid = args64->stransid;
5123         args32->rtransid = args64->rtransid;
5124         args32->stime.sec = args64->stime.sec;
5125         args32->stime.nsec = args64->stime.nsec;
5126         args32->rtime.sec = args64->rtime.sec;
5127         args32->rtime.nsec = args64->rtime.nsec;
5128         args32->flags = args64->flags;
5129
5130         ret = copy_to_user(arg, args32, sizeof(*args32));
5131         if (ret)
5132                 ret = -EFAULT;
5133
5134 out:
5135         kfree(args32);
5136         kfree(args64);
5137         return ret;
5138 }
5139 #endif
5140
5141 static long btrfs_ioctl_set_received_subvol(struct file *file,
5142                                             void __user *arg)
5143 {
5144         struct btrfs_ioctl_received_subvol_args *sa = NULL;
5145         int ret = 0;
5146
5147         sa = memdup_user(arg, sizeof(*sa));
5148         if (IS_ERR(sa))
5149                 return PTR_ERR(sa);
5150
5151         ret = _btrfs_ioctl_set_received_subvol(file, sa);
5152
5153         if (ret)
5154                 goto out;
5155
5156         ret = copy_to_user(arg, sa, sizeof(*sa));
5157         if (ret)
5158                 ret = -EFAULT;
5159
5160 out:
5161         kfree(sa);
5162         return ret;
5163 }
5164
5165 static int btrfs_ioctl_get_fslabel(struct file *file, void __user *arg)
5166 {
5167         struct inode *inode = file_inode(file);
5168         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
5169         size_t len;
5170         int ret;
5171         char label[BTRFS_LABEL_SIZE];
5172
5173         spin_lock(&fs_info->super_lock);
5174         memcpy(label, fs_info->super_copy->label, BTRFS_LABEL_SIZE);
5175         spin_unlock(&fs_info->super_lock);
5176
5177         len = strnlen(label, BTRFS_LABEL_SIZE);
5178
5179         if (len == BTRFS_LABEL_SIZE) {
5180                 btrfs_warn(fs_info,
5181                            "label is too long, return the first %zu bytes",
5182                            --len);
5183         }
5184
5185         ret = copy_to_user(arg, label, len);
5186
5187         return ret ? -EFAULT : 0;
5188 }
5189
5190 static int btrfs_ioctl_set_fslabel(struct file *file, void __user *arg)
5191 {
5192         struct inode *inode = file_inode(file);
5193         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
5194         struct btrfs_root *root = BTRFS_I(inode)->root;
5195         struct btrfs_super_block *super_block = fs_info->super_copy;
5196         struct btrfs_trans_handle *trans;
5197         char label[BTRFS_LABEL_SIZE];
5198         int ret;
5199
5200         if (!capable(CAP_SYS_ADMIN))
5201                 return -EPERM;
5202
5203         if (copy_from_user(label, arg, sizeof(label)))
5204                 return -EFAULT;
5205
5206         if (strnlen(label, BTRFS_LABEL_SIZE) == BTRFS_LABEL_SIZE) {
5207                 btrfs_err(fs_info,
5208                           "unable to set label with more than %d bytes",
5209                           BTRFS_LABEL_SIZE - 1);
5210                 return -EINVAL;
5211         }
5212
5213         ret = mnt_want_write_file(file);
5214         if (ret)
5215                 return ret;
5216
5217         trans = btrfs_start_transaction(root, 0);
5218         if (IS_ERR(trans)) {
5219                 ret = PTR_ERR(trans);
5220                 goto out_unlock;
5221         }
5222
5223         spin_lock(&fs_info->super_lock);
5224         strcpy(super_block->label, label);
5225         spin_unlock(&fs_info->super_lock);
5226         ret = btrfs_commit_transaction(trans);
5227
5228 out_unlock:
5229         mnt_drop_write_file(file);
5230         return ret;
5231 }
5232
5233 #define INIT_FEATURE_FLAGS(suffix) \
5234         { .compat_flags = BTRFS_FEATURE_COMPAT_##suffix, \
5235           .compat_ro_flags = BTRFS_FEATURE_COMPAT_RO_##suffix, \
5236           .incompat_flags = BTRFS_FEATURE_INCOMPAT_##suffix }
5237
5238 int btrfs_ioctl_get_supported_features(void __user *arg)
5239 {
5240         static const struct btrfs_ioctl_feature_flags features[3] = {
5241                 INIT_FEATURE_FLAGS(SUPP),
5242                 INIT_FEATURE_FLAGS(SAFE_SET),
5243                 INIT_FEATURE_FLAGS(SAFE_CLEAR)
5244         };
5245
5246         if (copy_to_user(arg, &features, sizeof(features)))
5247                 return -EFAULT;
5248
5249         return 0;
5250 }
5251
5252 static int btrfs_ioctl_get_features(struct file *file, void __user *arg)
5253 {
5254         struct inode *inode = file_inode(file);
5255         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
5256         struct btrfs_super_block *super_block = fs_info->super_copy;
5257         struct btrfs_ioctl_feature_flags features;
5258
5259         features.compat_flags = btrfs_super_compat_flags(super_block);
5260         features.compat_ro_flags = btrfs_super_compat_ro_flags(super_block);
5261         features.incompat_flags = btrfs_super_incompat_flags(super_block);
5262
5263         if (copy_to_user(arg, &features, sizeof(features)))
5264                 return -EFAULT;
5265
5266         return 0;
5267 }
5268
5269 static int check_feature_bits(struct btrfs_fs_info *fs_info,
5270                               enum btrfs_feature_set set,
5271                               u64 change_mask, u64 flags, u64 supported_flags,
5272                               u64 safe_set, u64 safe_clear)
5273 {
5274         const char *type = btrfs_feature_set_name(set);
5275         char *names;
5276         u64 disallowed, unsupported;
5277         u64 set_mask = flags & change_mask;
5278         u64 clear_mask = ~flags & change_mask;
5279
5280         unsupported = set_mask & ~supported_flags;
5281         if (unsupported) {
5282                 names = btrfs_printable_features(set, unsupported);
5283                 if (names) {
5284                         btrfs_warn(fs_info,
5285                                    "this kernel does not support the %s feature bit%s",
5286                                    names, strchr(names, ',') ? "s" : "");
5287                         kfree(names);
5288                 } else
5289                         btrfs_warn(fs_info,
5290                                    "this kernel does not support %s bits 0x%llx",
5291                                    type, unsupported);
5292                 return -EOPNOTSUPP;
5293         }
5294
5295         disallowed = set_mask & ~safe_set;
5296         if (disallowed) {
5297                 names = btrfs_printable_features(set, disallowed);
5298                 if (names) {
5299                         btrfs_warn(fs_info,
5300                                    "can't set the %s feature bit%s while mounted",
5301                                    names, strchr(names, ',') ? "s" : "");
5302                         kfree(names);
5303                 } else
5304                         btrfs_warn(fs_info,
5305                                    "can't set %s bits 0x%llx while mounted",
5306                                    type, disallowed);
5307                 return -EPERM;
5308         }
5309
5310         disallowed = clear_mask & ~safe_clear;
5311         if (disallowed) {
5312                 names = btrfs_printable_features(set, disallowed);
5313                 if (names) {
5314                         btrfs_warn(fs_info,
5315                                    "can't clear the %s feature bit%s while mounted",
5316                                    names, strchr(names, ',') ? "s" : "");
5317                         kfree(names);
5318                 } else
5319                         btrfs_warn(fs_info,
5320                                    "can't clear %s bits 0x%llx while mounted",
5321                                    type, disallowed);
5322                 return -EPERM;
5323         }
5324
5325         return 0;
5326 }
5327
5328 #define check_feature(fs_info, change_mask, flags, mask_base)   \
5329 check_feature_bits(fs_info, FEAT_##mask_base, change_mask, flags,       \
5330                    BTRFS_FEATURE_ ## mask_base ## _SUPP,        \
5331                    BTRFS_FEATURE_ ## mask_base ## _SAFE_SET,    \
5332                    BTRFS_FEATURE_ ## mask_base ## _SAFE_CLEAR)
5333
5334 static int btrfs_ioctl_set_features(struct file *file, void __user *arg)
5335 {
5336         struct inode *inode = file_inode(file);
5337         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
5338         struct btrfs_root *root = BTRFS_I(inode)->root;
5339         struct btrfs_super_block *super_block = fs_info->super_copy;
5340         struct btrfs_ioctl_feature_flags flags[2];
5341         struct btrfs_trans_handle *trans;
5342         u64 newflags;
5343         int ret;
5344
5345         if (!capable(CAP_SYS_ADMIN))
5346                 return -EPERM;
5347
5348         if (copy_from_user(flags, arg, sizeof(flags)))
5349                 return -EFAULT;
5350
5351         /* Nothing to do */
5352         if (!flags[0].compat_flags && !flags[0].compat_ro_flags &&
5353             !flags[0].incompat_flags)
5354                 return 0;
5355
5356         ret = check_feature(fs_info, flags[0].compat_flags,
5357                             flags[1].compat_flags, COMPAT);
5358         if (ret)
5359                 return ret;
5360
5361         ret = check_feature(fs_info, flags[0].compat_ro_flags,
5362                             flags[1].compat_ro_flags, COMPAT_RO);
5363         if (ret)
5364                 return ret;
5365
5366         ret = check_feature(fs_info, flags[0].incompat_flags,
5367                             flags[1].incompat_flags, INCOMPAT);
5368         if (ret)
5369                 return ret;
5370
5371         ret = mnt_want_write_file(file);
5372         if (ret)
5373                 return ret;
5374
5375         trans = btrfs_start_transaction(root, 0);
5376         if (IS_ERR(trans)) {
5377                 ret = PTR_ERR(trans);
5378                 goto out_drop_write;
5379         }
5380
5381         spin_lock(&fs_info->super_lock);
5382         newflags = btrfs_super_compat_flags(super_block);
5383         newflags |= flags[0].compat_flags & flags[1].compat_flags;
5384         newflags &= ~(flags[0].compat_flags & ~flags[1].compat_flags);
5385         btrfs_set_super_compat_flags(super_block, newflags);
5386
5387         newflags = btrfs_super_compat_ro_flags(super_block);
5388         newflags |= flags[0].compat_ro_flags & flags[1].compat_ro_flags;
5389         newflags &= ~(flags[0].compat_ro_flags & ~flags[1].compat_ro_flags);
5390         btrfs_set_super_compat_ro_flags(super_block, newflags);
5391
5392         newflags = btrfs_super_incompat_flags(super_block);
5393         newflags |= flags[0].incompat_flags & flags[1].incompat_flags;
5394         newflags &= ~(flags[0].incompat_flags & ~flags[1].incompat_flags);
5395         btrfs_set_super_incompat_flags(super_block, newflags);
5396         spin_unlock(&fs_info->super_lock);
5397
5398         ret = btrfs_commit_transaction(trans);
5399 out_drop_write:
5400         mnt_drop_write_file(file);
5401
5402         return ret;
5403 }
5404
5405 static int _btrfs_ioctl_send(struct file *file, void __user *argp, bool compat)
5406 {
5407         struct btrfs_ioctl_send_args *arg;
5408         int ret;
5409
5410         if (compat) {
5411 #if defined(CONFIG_64BIT) && defined(CONFIG_COMPAT)
5412                 struct btrfs_ioctl_send_args_32 args32;
5413
5414                 ret = copy_from_user(&args32, argp, sizeof(args32));
5415                 if (ret)
5416                         return -EFAULT;
5417                 arg = kzalloc(sizeof(*arg), GFP_KERNEL);
5418                 if (!arg)
5419                         return -ENOMEM;
5420                 arg->send_fd = args32.send_fd;
5421                 arg->clone_sources_count = args32.clone_sources_count;
5422                 arg->clone_sources = compat_ptr(args32.clone_sources);
5423                 arg->parent_root = args32.parent_root;
5424                 arg->flags = args32.flags;
5425                 memcpy(arg->reserved, args32.reserved,
5426                        sizeof(args32.reserved));
5427 #else
5428                 return -ENOTTY;
5429 #endif
5430         } else {
5431                 arg = memdup_user(argp, sizeof(*arg));
5432                 if (IS_ERR(arg))
5433                         return PTR_ERR(arg);
5434         }
5435         ret = btrfs_ioctl_send(file, arg);
5436         kfree(arg);
5437         return ret;
5438 }
5439
5440 long btrfs_ioctl(struct file *file, unsigned int
5441                 cmd, unsigned long arg)
5442 {
5443         struct inode *inode = file_inode(file);
5444         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
5445         struct btrfs_root *root = BTRFS_I(inode)->root;
5446         void __user *argp = (void __user *)arg;
5447
5448         switch (cmd) {
5449         case FS_IOC_GETFLAGS:
5450                 return btrfs_ioctl_getflags(file, argp);
5451         case FS_IOC_SETFLAGS:
5452                 return btrfs_ioctl_setflags(file, argp);
5453         case FS_IOC_GETVERSION:
5454                 return btrfs_ioctl_getversion(file, argp);
5455         case FS_IOC_GETFSLABEL:
5456                 return btrfs_ioctl_get_fslabel(file, argp);
5457         case FS_IOC_SETFSLABEL:
5458                 return btrfs_ioctl_set_fslabel(file, argp);
5459         case FITRIM:
5460                 return btrfs_ioctl_fitrim(file, argp);
5461         case BTRFS_IOC_SNAP_CREATE:
5462                 return btrfs_ioctl_snap_create(file, argp, 0);
5463         case BTRFS_IOC_SNAP_CREATE_V2:
5464                 return btrfs_ioctl_snap_create_v2(file, argp, 0);
5465         case BTRFS_IOC_SUBVOL_CREATE:
5466                 return btrfs_ioctl_snap_create(file, argp, 1);
5467         case BTRFS_IOC_SUBVOL_CREATE_V2:
5468                 return btrfs_ioctl_snap_create_v2(file, argp, 1);
5469         case BTRFS_IOC_SNAP_DESTROY:
5470                 return btrfs_ioctl_snap_destroy(file, argp);
5471         case BTRFS_IOC_SUBVOL_GETFLAGS:
5472                 return btrfs_ioctl_subvol_getflags(file, argp);
5473         case BTRFS_IOC_SUBVOL_SETFLAGS:
5474                 return btrfs_ioctl_subvol_setflags(file, argp);
5475         case BTRFS_IOC_DEFAULT_SUBVOL:
5476                 return btrfs_ioctl_default_subvol(file, argp);
5477         case BTRFS_IOC_DEFRAG:
5478                 return btrfs_ioctl_defrag(file, NULL);
5479         case BTRFS_IOC_DEFRAG_RANGE:
5480                 return btrfs_ioctl_defrag(file, argp);
5481         case BTRFS_IOC_RESIZE:
5482                 return btrfs_ioctl_resize(file, argp);
5483         case BTRFS_IOC_ADD_DEV:
5484                 return btrfs_ioctl_add_dev(fs_info, argp);
5485         case BTRFS_IOC_RM_DEV:
5486                 return btrfs_ioctl_rm_dev(file, argp);
5487         case BTRFS_IOC_RM_DEV_V2:
5488                 return btrfs_ioctl_rm_dev_v2(file, argp);
5489         case BTRFS_IOC_FS_INFO:
5490                 return btrfs_ioctl_fs_info(fs_info, argp);
5491         case BTRFS_IOC_DEV_INFO:
5492                 return btrfs_ioctl_dev_info(fs_info, argp);
5493         case BTRFS_IOC_BALANCE:
5494                 return btrfs_ioctl_balance(file, NULL);
5495         case BTRFS_IOC_TREE_SEARCH:
5496                 return btrfs_ioctl_tree_search(file, argp);
5497         case BTRFS_IOC_TREE_SEARCH_V2:
5498                 return btrfs_ioctl_tree_search_v2(file, argp);
5499         case BTRFS_IOC_INO_LOOKUP:
5500                 return btrfs_ioctl_ino_lookup(file, argp);
5501         case BTRFS_IOC_INO_PATHS:
5502                 return btrfs_ioctl_ino_to_path(root, argp);
5503         case BTRFS_IOC_LOGICAL_INO:
5504                 return btrfs_ioctl_logical_to_ino(fs_info, argp, 1);
5505         case BTRFS_IOC_LOGICAL_INO_V2:
5506                 return btrfs_ioctl_logical_to_ino(fs_info, argp, 2);
5507         case BTRFS_IOC_SPACE_INFO:
5508                 return btrfs_ioctl_space_info(fs_info, argp);
5509         case BTRFS_IOC_SYNC: {
5510                 int ret;
5511
5512                 ret = btrfs_start_delalloc_roots(fs_info, -1);
5513                 if (ret)
5514                         return ret;
5515                 ret = btrfs_sync_fs(inode->i_sb, 1);
5516                 /*
5517                  * The transaction thread may want to do more work,
5518                  * namely it pokes the cleaner kthread that will start
5519                  * processing uncleaned subvols.
5520                  */
5521                 wake_up_process(fs_info->transaction_kthread);
5522                 return ret;
5523         }
5524         case BTRFS_IOC_START_SYNC:
5525                 return btrfs_ioctl_start_sync(root, argp);
5526         case BTRFS_IOC_WAIT_SYNC:
5527                 return btrfs_ioctl_wait_sync(fs_info, argp);
5528         case BTRFS_IOC_SCRUB:
5529                 return btrfs_ioctl_scrub(file, argp);
5530         case BTRFS_IOC_SCRUB_CANCEL:
5531                 return btrfs_ioctl_scrub_cancel(fs_info);
5532         case BTRFS_IOC_SCRUB_PROGRESS:
5533                 return btrfs_ioctl_scrub_progress(fs_info, argp);
5534         case BTRFS_IOC_BALANCE_V2:
5535                 return btrfs_ioctl_balance(file, argp);
5536         case BTRFS_IOC_BALANCE_CTL:
5537                 return btrfs_ioctl_balance_ctl(fs_info, arg);
5538         case BTRFS_IOC_BALANCE_PROGRESS:
5539                 return btrfs_ioctl_balance_progress(fs_info, argp);
5540         case BTRFS_IOC_SET_RECEIVED_SUBVOL:
5541                 return btrfs_ioctl_set_received_subvol(file, argp);
5542 #ifdef CONFIG_64BIT
5543         case BTRFS_IOC_SET_RECEIVED_SUBVOL_32:
5544                 return btrfs_ioctl_set_received_subvol_32(file, argp);
5545 #endif
5546         case BTRFS_IOC_SEND:
5547                 return _btrfs_ioctl_send(file, argp, false);
5548 #if defined(CONFIG_64BIT) && defined(CONFIG_COMPAT)
5549         case BTRFS_IOC_SEND_32:
5550                 return _btrfs_ioctl_send(file, argp, true);
5551 #endif
5552         case BTRFS_IOC_GET_DEV_STATS:
5553                 return btrfs_ioctl_get_dev_stats(fs_info, argp);
5554         case BTRFS_IOC_QUOTA_CTL:
5555                 return btrfs_ioctl_quota_ctl(file, argp);
5556         case BTRFS_IOC_QGROUP_ASSIGN:
5557                 return btrfs_ioctl_qgroup_assign(file, argp);
5558         case BTRFS_IOC_QGROUP_CREATE:
5559                 return btrfs_ioctl_qgroup_create(file, argp);
5560         case BTRFS_IOC_QGROUP_LIMIT:
5561                 return btrfs_ioctl_qgroup_limit(file, argp);
5562         case BTRFS_IOC_QUOTA_RESCAN:
5563                 return btrfs_ioctl_quota_rescan(file, argp);
5564         case BTRFS_IOC_QUOTA_RESCAN_STATUS:
5565                 return btrfs_ioctl_quota_rescan_status(file, argp);
5566         case BTRFS_IOC_QUOTA_RESCAN_WAIT:
5567                 return btrfs_ioctl_quota_rescan_wait(file, argp);
5568         case BTRFS_IOC_DEV_REPLACE:
5569                 return btrfs_ioctl_dev_replace(fs_info, argp);
5570         case BTRFS_IOC_GET_SUPPORTED_FEATURES:
5571                 return btrfs_ioctl_get_supported_features(argp);
5572         case BTRFS_IOC_GET_FEATURES:
5573                 return btrfs_ioctl_get_features(file, argp);
5574         case BTRFS_IOC_SET_FEATURES:
5575                 return btrfs_ioctl_set_features(file, argp);
5576         case FS_IOC_FSGETXATTR:
5577                 return btrfs_ioctl_fsgetxattr(file, argp);
5578         case FS_IOC_FSSETXATTR:
5579                 return btrfs_ioctl_fssetxattr(file, argp);
5580         case BTRFS_IOC_GET_SUBVOL_INFO:
5581                 return btrfs_ioctl_get_subvol_info(file, argp);
5582         case BTRFS_IOC_GET_SUBVOL_ROOTREF:
5583                 return btrfs_ioctl_get_subvol_rootref(file, argp);
5584         case BTRFS_IOC_INO_LOOKUP_USER:
5585                 return btrfs_ioctl_ino_lookup_user(file, argp);
5586         }
5587
5588         return -ENOTTY;
5589 }
5590
5591 #ifdef CONFIG_COMPAT
5592 long btrfs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
5593 {
5594         /*
5595          * These all access 32-bit values anyway so no further
5596          * handling is necessary.
5597          */
5598         switch (cmd) {
5599         case FS_IOC32_GETFLAGS:
5600                 cmd = FS_IOC_GETFLAGS;
5601                 break;
5602         case FS_IOC32_SETFLAGS:
5603                 cmd = FS_IOC_SETFLAGS;
5604                 break;
5605         case FS_IOC32_GETVERSION:
5606                 cmd = FS_IOC_GETVERSION;
5607                 break;
5608         }
5609
5610         return btrfs_ioctl(file, cmd, (unsigned long) compat_ptr(arg));
5611 }
5612 #endif