git.oblomov.eu Git - linux-2.6/blob - fs/btrfs/ioctl.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 #include <linux/kernel.h>
  20 #include <linux/bio.h>
  21 #include <linux/buffer_head.h>
  22 #include <linux/file.h>
  23 #include <linux/fs.h>
  24 #include <linux/fsnotify.h>
  25 #include <linux/pagemap.h>
  26 #include <linux/highmem.h>
  27 #include <linux/time.h>
  28 #include <linux/init.h>
  29 #include <linux/string.h>
  30 #include <linux/backing-dev.h>
  31 #include <linux/mount.h>
  32 #include <linux/mpage.h>
  33 #include <linux/namei.h>
  34 #include <linux/swap.h>
  35 #include <linux/writeback.h>
  36 #include <linux/statfs.h>
  37 #include <linux/compat.h>
  38 #include <linux/bit_spinlock.h>
  39 #include <linux/security.h>
  40 #include <linux/xattr.h>
  41 #include <linux/vmalloc.h>
  42 #include "compat.h"
  43 #include "ctree.h"
  44 #include "disk-io.h"
  45 #include "transaction.h"
  46 #include "btrfs_inode.h"
  47 #include "ioctl.h"
  48 #include "print-tree.h"
  49 #include "volumes.h"
  50 #include "locking.h"
  51
  52 /* Mask out flags that are inappropriate for the given type of inode. */
  53 static inline __u32 btrfs_mask_flags(umode_t mode, __u32 flags)
  54 {
  55         if (S_ISDIR(mode))
  56                 return flags;
  57         else if (S_ISREG(mode))
  58                 return flags & ~FS_DIRSYNC_FL;
  59         else
  60                 return flags & (FS_NODUMP_FL | FS_NOATIME_FL);
  61 }
  62
  63 /*
  64  * Export inode flags to the format expected by the FS_IOC_GETFLAGS ioctl.
  65  */
  66 static unsigned int btrfs_flags_to_ioctl(unsigned int flags)
  67 {
  68         unsigned int iflags = 0;
  69
  70         if (flags & BTRFS_INODE_SYNC)
  71                 iflags |= FS_SYNC_FL;
  72         if (flags & BTRFS_INODE_IMMUTABLE)
  73                 iflags |= FS_IMMUTABLE_FL;
  74         if (flags & BTRFS_INODE_APPEND)
  75                 iflags |= FS_APPEND_FL;
  76         if (flags & BTRFS_INODE_NODUMP)
  77                 iflags |= FS_NODUMP_FL;
  78         if (flags & BTRFS_INODE_NOATIME)
  79                 iflags |= FS_NOATIME_FL;
  80         if (flags & BTRFS_INODE_DIRSYNC)
  81                 iflags |= FS_DIRSYNC_FL;
  82
  83         return iflags;
  84 }
  85
  86 /*
  87  * Update inode->i_flags based on the btrfs internal flags.
  88  */
  89 void btrfs_update_iflags(struct inode *inode)
  90 {
  91         struct btrfs_inode *ip = BTRFS_I(inode);
  92
  93         inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
  94
  95         if (ip->flags & BTRFS_INODE_SYNC)
  96                 inode->i_flags |= S_SYNC;
  97         if (ip->flags & BTRFS_INODE_IMMUTABLE)
  98                 inode->i_flags |= S_IMMUTABLE;
  99         if (ip->flags & BTRFS_INODE_APPEND)
 100                 inode->i_flags |= S_APPEND;
 101         if (ip->flags & BTRFS_INODE_NOATIME)
 102                 inode->i_flags |= S_NOATIME;
 103         if (ip->flags & BTRFS_INODE_DIRSYNC)
 104                 inode->i_flags |= S_DIRSYNC;
 105 }
 106
 107 /*
 108  * Inherit flags from the parent inode.
 109  *
 110  * Unlike extN we don't have any flags we don't want to inherit currently.
 111  */
 112 void btrfs_inherit_iflags(struct inode *inode, struct inode *dir)
 113 {
 114         unsigned int flags;
 115
 116         if (!dir)
 117                 return;
 118
 119         flags = BTRFS_I(dir)->flags;
 120
 121         if (S_ISREG(inode->i_mode))
 122                 flags &= ~BTRFS_INODE_DIRSYNC;
 123         else if (!S_ISDIR(inode->i_mode))
 124                 flags &= (BTRFS_INODE_NODUMP | BTRFS_INODE_NOATIME);
 125
 126         BTRFS_I(inode)->flags = flags;
 127         btrfs_update_iflags(inode);
 128 }
 129
 130 static int btrfs_ioctl_getflags(struct file *file, void __user *arg)
 131 {
 132         struct btrfs_inode *ip = BTRFS_I(file->f_path.dentry->d_inode);
 133         unsigned int flags = btrfs_flags_to_ioctl(ip->flags);
 134
 135         if (copy_to_user(arg, &flags, sizeof(flags)))
 136                 return -EFAULT;
 137         return 0;
 138 }
 139
 140 static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
 141 {
 142         struct inode *inode = file->f_path.dentry->d_inode;
 143         struct btrfs_inode *ip = BTRFS_I(inode);
 144         struct btrfs_root *root = ip->root;
 145         struct btrfs_trans_handle *trans;
 146         unsigned int flags, oldflags;
 147         int ret;
 148
 149         if (copy_from_user(&flags, arg, sizeof(flags)))
 150                 return -EFAULT;
 151
 152         if (flags & ~(FS_IMMUTABLE_FL | FS_APPEND_FL | \
 153                       FS_NOATIME_FL | FS_NODUMP_FL | \
 154                       FS_SYNC_FL | FS_DIRSYNC_FL))
 155                 return -EOPNOTSUPP;
 156
 157         if (!is_owner_or_cap(inode))
 158                 return -EACCES;
 159
 160         mutex_lock(&inode->i_mutex);
 161
 162         flags = btrfs_mask_flags(inode->i_mode, flags);
 163         oldflags = btrfs_flags_to_ioctl(ip->flags);
 164         if ((flags ^ oldflags) & (FS_APPEND_FL | FS_IMMUTABLE_FL)) {
 165                 if (!capable(CAP_LINUX_IMMUTABLE)) {
 166                         ret = -EPERM;
 167                         goto out_unlock;
 168                 }
 169         }
 170
 171         ret = mnt_want_write(file->f_path.mnt);
 172         if (ret)
 173                 goto out_unlock;
 174
 175         if (flags & FS_SYNC_FL)
 176                 ip->flags |= BTRFS_INODE_SYNC;
 177         else
 178                 ip->flags &= ~BTRFS_INODE_SYNC;
 179         if (flags & FS_IMMUTABLE_FL)
 180                 ip->flags |= BTRFS_INODE_IMMUTABLE;
 181         else
 182                 ip->flags &= ~BTRFS_INODE_IMMUTABLE;
 183         if (flags & FS_APPEND_FL)
 184                 ip->flags |= BTRFS_INODE_APPEND;
 185         else
 186                 ip->flags &= ~BTRFS_INODE_APPEND;
 187         if (flags & FS_NODUMP_FL)
 188                 ip->flags |= BTRFS_INODE_NODUMP;
 189         else
 190                 ip->flags &= ~BTRFS_INODE_NODUMP;
 191         if (flags & FS_NOATIME_FL)
 192                 ip->flags |= BTRFS_INODE_NOATIME;
 193         else
 194                 ip->flags &= ~BTRFS_INODE_NOATIME;
 195         if (flags & FS_DIRSYNC_FL)
 196                 ip->flags |= BTRFS_INODE_DIRSYNC;
 197         else
 198                 ip->flags &= ~BTRFS_INODE_DIRSYNC;
 199
 200
 201         trans = btrfs_join_transaction(root, 1);
 202         BUG_ON(!trans);
 203
 204         ret = btrfs_update_inode(trans, root, inode);
 205         BUG_ON(ret);
 206
 207         btrfs_update_iflags(inode);
 208         inode->i_ctime = CURRENT_TIME;
 209         btrfs_end_transaction(trans, root);
 210
 211         mnt_drop_write(file->f_path.mnt);
 212  out_unlock:
 213         mutex_unlock(&inode->i_mutex);
 214         return 0;
 215 }
 216
 217 static int btrfs_ioctl_getversion(struct file *file, int __user *arg)
 218 {
 219         struct inode *inode = file->f_path.dentry->d_inode;
 220
 221         return put_user(inode->i_generation, arg);
 222 }
 223
 224 static noinline int create_subvol(struct btrfs_root *root,
 225                                   struct dentry *dentry,
 226                                   char *name, int namelen)
 227 {
 228         struct btrfs_trans_handle *trans;
 229         struct btrfs_key key;
 230         struct btrfs_root_item root_item;
 231         struct btrfs_inode_item *inode_item;
 232         struct extent_buffer *leaf;
 233         struct btrfs_root *new_root = root;
 234         struct inode *dir;
 235         int ret;
 236         int err;
 237         u64 objectid;
 238         u64 new_dirid = BTRFS_FIRST_FREE_OBJECTID;
 239         u64 index = 0;
 240         unsigned long nr = 1;
 241
 242         ret = btrfs_check_metadata_free_space(root);
 243         if (ret)
 244                 goto fail_commit;
 245
 246         trans = btrfs_start_transaction(root, 1);
 247         BUG_ON(!trans);
 248
 249         ret = btrfs_find_free_objectid(trans, root->fs_info->tree_root,
 250                                        0, &objectid);
 251         if (ret)
 252                 goto fail;
 253
 254         leaf = btrfs_alloc_free_block(trans, root, root->leafsize,
 255                                       0, objectid, NULL, 0, 0, 0);
 256         if (IS_ERR(leaf)) {
 257                 ret = PTR_ERR(leaf);
 258                 goto fail;
 259         }
 260
 261         memset_extent_buffer(leaf, 0, 0, sizeof(struct btrfs_header));
 262         btrfs_set_header_bytenr(leaf, leaf->start);
 263         btrfs_set_header_generation(leaf, trans->transid);
 264         btrfs_set_header_backref_rev(leaf, BTRFS_MIXED_BACKREF_REV);
 265         btrfs_set_header_owner(leaf, objectid);
 266
 267         write_extent_buffer(leaf, root->fs_info->fsid,
 268                             (unsigned long)btrfs_header_fsid(leaf),
 269                             BTRFS_FSID_SIZE);
 270         write_extent_buffer(leaf, root->fs_info->chunk_tree_uuid,
 271                             (unsigned long)btrfs_header_chunk_tree_uuid(leaf),
 272                             BTRFS_UUID_SIZE);
 273         btrfs_mark_buffer_dirty(leaf);
 274
 275         inode_item = &root_item.inode;
 276         memset(inode_item, 0, sizeof(*inode_item));
 277         inode_item->generation = cpu_to_le64(1);
 278         inode_item->size = cpu_to_le64(3);
 279         inode_item->nlink = cpu_to_le32(1);
 280         inode_item->nbytes = cpu_to_le64(root->leafsize);
 281         inode_item->mode = cpu_to_le32(S_IFDIR | 0755);
 282
 283         btrfs_set_root_bytenr(&root_item, leaf->start);
 284         btrfs_set_root_generation(&root_item, trans->transid);
 285         btrfs_set_root_level(&root_item, 0);
 286         btrfs_set_root_refs(&root_item, 1);
 287         btrfs_set_root_used(&root_item, 0);
 288         btrfs_set_root_last_snapshot(&root_item, 0);
 289
 290         memset(&root_item.drop_progress, 0, sizeof(root_item.drop_progress));
 291         root_item.drop_level = 0;
 292
 293         btrfs_tree_unlock(leaf);
 294         free_extent_buffer(leaf);
 295         leaf = NULL;
 296
 297         btrfs_set_root_dirid(&root_item, new_dirid);
 298
 299         key.objectid = objectid;
 300         key.offset = 0;
 301         btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
 302         ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key,
 303                                 &root_item);
 304         if (ret)
 305                 goto fail;
 306
 307         /*
 308          * insert the directory item
 309          */
 310         key.offset = (u64)-1;
 311         dir = dentry->d_parent->d_inode;
 312         ret = btrfs_set_inode_index(dir, &index);
 313         BUG_ON(ret);
 314
 315         ret = btrfs_insert_dir_item(trans, root,
 316                                     name, namelen, dir->i_ino, &key,
 317                                     BTRFS_FT_DIR, index);
 318         if (ret)
 319                 goto fail;
 320
 321         btrfs_i_size_write(dir, dir->i_size + namelen * 2);
 322         ret = btrfs_update_inode(trans, root, dir);
 323         BUG_ON(ret);
 324
 325         /* add the backref first */
 326         ret = btrfs_add_root_ref(trans, root->fs_info->tree_root,
 327                                  objectid, BTRFS_ROOT_BACKREF_KEY,
 328                                  root->root_key.objectid,
 329                                  dir->i_ino, index, name, namelen);
 330
 331         BUG_ON(ret);
 332
 333         /* now add the forward ref */
 334         ret = btrfs_add_root_ref(trans, root->fs_info->tree_root,
 335                                  root->root_key.objectid, BTRFS_ROOT_REF_KEY,
 336                                  objectid,
 337                                  dir->i_ino, index, name, namelen);
 338
 339         BUG_ON(ret);
 340
 341         ret = btrfs_commit_transaction(trans, root);
 342         if (ret)
 343                 goto fail_commit;
 344
 345         new_root = btrfs_read_fs_root_no_name(root->fs_info, &key);
 346         BUG_ON(!new_root);
 347
 348         trans = btrfs_start_transaction(new_root, 1);
 349         BUG_ON(!trans);
 350
 351         ret = btrfs_create_subvol_root(trans, new_root, dentry, new_dirid,
 352                                        BTRFS_I(dir)->block_group);
 353         if (ret)
 354                 goto fail;
 355
 356 fail:
 357         nr = trans->blocks_used;
 358         err = btrfs_commit_transaction(trans, new_root);
 359         if (err && !ret)
 360                 ret = err;
 361 fail_commit:
 362         btrfs_btree_balance_dirty(root, nr);
 363         return ret;
 364 }
 365
 366 static int create_snapshot(struct btrfs_root *root, struct dentry *dentry,
 367                            char *name, int namelen)
 368 {
 369         struct btrfs_pending_snapshot *pending_snapshot;
 370         struct btrfs_trans_handle *trans;
 371         int ret = 0;
 372         int err;
 373         unsigned long nr = 0;
 374
 375         if (!root->ref_cows)
 376                 return -EINVAL;
 377
 378         ret = btrfs_check_metadata_free_space(root);
 379         if (ret)
 380                 goto fail_unlock;
 381
 382         pending_snapshot = kzalloc(sizeof(*pending_snapshot), GFP_NOFS);
 383         if (!pending_snapshot) {
 384                 ret = -ENOMEM;
 385                 goto fail_unlock;
 386         }
 387         pending_snapshot->name = kmalloc(namelen + 1, GFP_NOFS);
 388         if (!pending_snapshot->name) {
 389                 ret = -ENOMEM;
 390                 kfree(pending_snapshot);
 391                 goto fail_unlock;
 392         }
 393         memcpy(pending_snapshot->name, name, namelen);
 394         pending_snapshot->name[namelen] = '\0';
 395         pending_snapshot->dentry = dentry;
 396         trans = btrfs_start_transaction(root, 1);
 397         BUG_ON(!trans);
 398         pending_snapshot->root = root;
 399         list_add(&pending_snapshot->list,
 400                  &trans->transaction->pending_snapshots);
 401         err = btrfs_commit_transaction(trans, root);
 402
 403 fail_unlock:
 404         btrfs_btree_balance_dirty(root, nr);
 405         return ret;
 406 }
 407
 408 /* copy of may_create in fs/namei.c() */
 409 static inline int btrfs_may_create(struct inode *dir, struct dentry *child)
 410 {
 411         if (child->d_inode)
 412                 return -EEXIST;
 413         if (IS_DEADDIR(dir))
 414                 return -ENOENT;
 415         return inode_permission(dir, MAY_WRITE | MAY_EXEC);
 416 }
 417
 418 /*
 419  * Create a new subvolume below @parent.  This is largely modeled after
 420  * sys_mkdirat and vfs_mkdir, but we only do a single component lookup
 421  * inside this filesystem so it's quite a bit simpler.
 422  */
 423 static noinline int btrfs_mksubvol(struct path *parent, char *name,
 424                                    int mode, int namelen,
 425                                    struct btrfs_root *snap_src)
 426 {
 427         struct dentry *dentry;
 428         int error;
 429
 430         mutex_lock_nested(&parent->dentry->d_inode->i_mutex, I_MUTEX_PARENT);
 431
 432         dentry = lookup_one_len(name, parent->dentry, namelen);
 433         error = PTR_ERR(dentry);
 434         if (IS_ERR(dentry))
 435                 goto out_unlock;
 436
 437         error = -EEXIST;
 438         if (dentry->d_inode)
 439                 goto out_dput;
 440
 441         if (!IS_POSIXACL(parent->dentry->d_inode))
 442                 mode &= ~current_umask();
 443
 444         error = mnt_want_write(parent->mnt);
 445         if (error)
 446                 goto out_dput;
 447
 448         error = btrfs_may_create(parent->dentry->d_inode, dentry);
 449         if (error)
 450                 goto out_drop_write;
 451
 452         /*
 453          * Actually perform the low-level subvolume creation after all
 454          * this VFS fuzz.
 455          *
 456          * Eventually we want to pass in an inode under which we create this
 457          * subvolume, but for now all are under the filesystem root.
 458          *
 459          * Also we should pass on the mode eventually to allow creating new
 460          * subvolume with specific mode bits.
 461          */
 462         if (snap_src) {
 463                 struct dentry *dir = dentry->d_parent;
 464                 struct dentry *test = dir->d_parent;
 465                 struct btrfs_path *path = btrfs_alloc_path();
 466                 int ret;
 467                 u64 test_oid;
 468                 u64 parent_oid = BTRFS_I(dir->d_inode)->root->root_key.objectid;
 469
 470                 test_oid = snap_src->root_key.objectid;
 471
 472                 ret = btrfs_find_root_ref(snap_src->fs_info->tree_root,
 473                                           path, parent_oid, test_oid);
 474                 if (ret == 0)
 475                         goto create;
 476                 btrfs_release_path(snap_src->fs_info->tree_root, path);
 477
 478                 /* we need to make sure we aren't creating a directory loop
 479                  * by taking a snapshot of something that has our current
 480                  * subvol in its directory tree.  So, this loops through
 481                  * the dentries and checks the forward refs for each subvolume
 482                  * to see if is references the subvolume where we are
 483                  * placing this new snapshot.
 484                  */
 485                 while (1) {
 486                         if (!test ||
 487                             dir == snap_src->fs_info->sb->s_root ||
 488                             test == snap_src->fs_info->sb->s_root ||
 489                             test->d_inode->i_sb != snap_src->fs_info->sb) {
 490                                 break;
 491                         }
 492                         if (S_ISLNK(test->d_inode->i_mode)) {
 493                                 printk(KERN_INFO "Btrfs symlink in snapshot "
 494                                        "path, failed\n");
 495                                 error = -EMLINK;
 496                                 btrfs_free_path(path);
 497                                 goto out_drop_write;
 498                         }
 499                         test_oid =
 500                                 BTRFS_I(test->d_inode)->root->root_key.objectid;
 501                         ret = btrfs_find_root_ref(snap_src->fs_info->tree_root,
 502                                   path, test_oid, parent_oid);
 503                         if (ret == 0) {
 504                                 printk(KERN_INFO "Btrfs snapshot creation "
 505                                        "failed, looping\n");
 506                                 error = -EMLINK;
 507                                 btrfs_free_path(path);
 508                                 goto out_drop_write;
 509                         }
 510                         btrfs_release_path(snap_src->fs_info->tree_root, path);
 511                         test = test->d_parent;
 512                 }
 513 create:
 514                 btrfs_free_path(path);
 515                 error = create_snapshot(snap_src, dentry, name, namelen);
 516         } else {
 517                 error = create_subvol(BTRFS_I(parent->dentry->d_inode)->root,
 518                                       dentry, name, namelen);
 519         }
 520         if (error)
 521                 goto out_drop_write;
 522
 523         fsnotify_mkdir(parent->dentry->d_inode, dentry);
 524 out_drop_write:
 525         mnt_drop_write(parent->mnt);
 526 out_dput:
 527         dput(dentry);
 528 out_unlock:
 529         mutex_unlock(&parent->dentry->d_inode->i_mutex);
 530         return error;
 531 }
 532
 533
 534 static int btrfs_defrag_file(struct file *file)
 535 {
 536         struct inode *inode = fdentry(file)->d_inode;
 537         struct btrfs_root *root = BTRFS_I(inode)->root;
 538         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
 539         struct btrfs_ordered_extent *ordered;
 540         struct page *page;
 541         unsigned long last_index;
 542         unsigned long ra_pages = root->fs_info->bdi.ra_pages;
 543         unsigned long total_read = 0;
 544         u64 page_start;
 545         u64 page_end;
 546         unsigned long i;
 547         int ret;
 548
 549         ret = btrfs_check_data_free_space(root, inode, inode->i_size);
 550         if (ret)
 551                 return -ENOSPC;
 552
 553         mutex_lock(&inode->i_mutex);
 554         last_index = inode->i_size >> PAGE_CACHE_SHIFT;
 555         for (i = 0; i <= last_index; i++) {
 556                 if (total_read % ra_pages == 0) {
 557                         btrfs_force_ra(inode->i_mapping, &file->f_ra, file, i,
 558                                        min(last_index, i + ra_pages - 1));
 559                 }
 560                 total_read++;
 561 again:
 562                 page = grab_cache_page(inode->i_mapping, i);
 563                 if (!page)
 564                         goto out_unlock;
 565                 if (!PageUptodate(page)) {
 566                         btrfs_readpage(NULL, page);
 567                         lock_page(page);
 568                         if (!PageUptodate(page)) {
 569                                 unlock_page(page);
 570                                 page_cache_release(page);
 571                                 goto out_unlock;
 572                         }
 573                 }
 574
 575                 wait_on_page_writeback(page);
 576
 577                 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
 578                 page_end = page_start + PAGE_CACHE_SIZE - 1;
 579                 lock_extent(io_tree, page_start, page_end, GFP_NOFS);
 580
 581                 ordered = btrfs_lookup_ordered_extent(inode, page_start);
 582                 if (ordered) {
 583                         unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
 584                         unlock_page(page);
 585                         page_cache_release(page);
 586                         btrfs_start_ordered_extent(inode, ordered, 1);
 587                         btrfs_put_ordered_extent(ordered);
 588                         goto again;
 589                 }
 590                 set_page_extent_mapped(page);
 591
 592                 /*
 593                  * this makes sure page_mkwrite is called on the
 594                  * page if it is dirtied again later
 595                  */
 596                 clear_page_dirty_for_io(page);
 597
 598                 btrfs_set_extent_delalloc(inode, page_start, page_end);
 599
 600                 unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
 601                 set_page_dirty(page);
 602                 unlock_page(page);
 603                 page_cache_release(page);
 604                 balance_dirty_pages_ratelimited_nr(inode->i_mapping, 1);
 605         }
 606
 607 out_unlock:
 608         mutex_unlock(&inode->i_mutex);
 609         return 0;
 610 }
 611
 612 static int btrfs_ioctl_resize(struct btrfs_root *root, void __user *arg)
 613 {
 614         u64 new_size;
 615         u64 old_size;
 616         u64 devid = 1;
 617         struct btrfs_ioctl_vol_args *vol_args;
 618         struct btrfs_trans_handle *trans;
 619         struct btrfs_device *device = NULL;
 620         char *sizestr;
 621         char *devstr = NULL;
 622         int ret = 0;
 623         int namelen;
 624         int mod = 0;
 625
 626         if (root->fs_info->sb->s_flags & MS_RDONLY)
 627                 return -EROFS;
 628
 629         if (!capable(CAP_SYS_ADMIN))
 630                 return -EPERM;
 631
 632         vol_args = memdup_user(arg, sizeof(*vol_args));
 633         if (IS_ERR(vol_args))
 634                 return PTR_ERR(vol_args);
 635
 636         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
 637         namelen = strlen(vol_args->name);
 638
 639         mutex_lock(&root->fs_info->volume_mutex);
 640         sizestr = vol_args->name;
 641         devstr = strchr(sizestr, ':');
 642         if (devstr) {
 643                 char *end;
 644                 sizestr = devstr + 1;
 645                 *devstr = '\0';
 646                 devstr = vol_args->name;
 647                 devid = simple_strtoull(devstr, &end, 10);
 648                 printk(KERN_INFO "resizing devid %llu\n",
 649                        (unsigned long long)devid);
 650         }
 651         device = btrfs_find_device(root, devid, NULL, NULL);
 652         if (!device) {
 653                 printk(KERN_INFO "resizer unable to find device %llu\n",
 654                        (unsigned long long)devid);
 655                 ret = -EINVAL;
 656                 goto out_unlock;
 657         }
 658         if (!strcmp(sizestr, "max"))
 659                 new_size = device->bdev->bd_inode->i_size;
 660         else {
 661                 if (sizestr[0] == '-') {
 662                         mod = -1;
 663                         sizestr++;
 664                 } else if (sizestr[0] == '+') {
 665                         mod = 1;
 666                         sizestr++;
 667                 }
 668                 new_size = btrfs_parse_size(sizestr);
 669                 if (new_size == 0) {
 670                         ret = -EINVAL;
 671                         goto out_unlock;
 672                 }
 673         }
 674
 675         old_size = device->total_bytes;
 676
 677         if (mod < 0) {
 678                 if (new_size > old_size) {
 679                         ret = -EINVAL;
 680                         goto out_unlock;
 681                 }
 682                 new_size = old_size - new_size;
 683         } else if (mod > 0) {
 684                 new_size = old_size + new_size;
 685         }
 686
 687         if (new_size < 256 * 1024 * 1024) {
 688                 ret = -EINVAL;
 689                 goto out_unlock;
 690         }
 691         if (new_size > device->bdev->bd_inode->i_size) {
 692                 ret = -EFBIG;
 693                 goto out_unlock;
 694         }
 695
 696         do_div(new_size, root->sectorsize);
 697         new_size *= root->sectorsize;
 698
 699         printk(KERN_INFO "new size for %s is %llu\n",
 700                 device->name, (unsigned long long)new_size);
 701
 702         if (new_size > old_size) {
 703                 trans = btrfs_start_transaction(root, 1);
 704                 ret = btrfs_grow_device(trans, device, new_size);
 705                 btrfs_commit_transaction(trans, root);
 706         } else {
 707                 ret = btrfs_shrink_device(device, new_size);
 708         }
 709
 710 out_unlock:
 711         mutex_unlock(&root->fs_info->volume_mutex);
 712         kfree(vol_args);
 713         return ret;
 714 }
 715
 716 static noinline int btrfs_ioctl_snap_create(struct file *file,
 717                                             void __user *arg, int subvol)
 718 {
 719         struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root;
 720         struct btrfs_ioctl_vol_args *vol_args;
 721         struct btrfs_dir_item *di;
 722         struct btrfs_path *path;
 723         struct file *src_file;
 724         u64 root_dirid;
 725         int namelen;
 726         int ret = 0;
 727
 728         if (root->fs_info->sb->s_flags & MS_RDONLY)
 729                 return -EROFS;
 730
 731         vol_args = memdup_user(arg, sizeof(*vol_args));
 732         if (IS_ERR(vol_args))
 733                 return PTR_ERR(vol_args);
 734
 735         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
 736         namelen = strlen(vol_args->name);
 737         if (strchr(vol_args->name, '/')) {
 738                 ret = -EINVAL;
 739                 goto out;
 740         }
 741
 742         path = btrfs_alloc_path();
 743         if (!path) {
 744                 ret = -ENOMEM;
 745                 goto out;
 746         }
 747
 748         root_dirid = root->fs_info->sb->s_root->d_inode->i_ino,
 749         di = btrfs_lookup_dir_item(NULL, root->fs_info->tree_root,
 750                             path, root_dirid,
 751                             vol_args->name, namelen, 0);
 752         btrfs_free_path(path);
 753
 754         if (di && !IS_ERR(di)) {
 755                 ret = -EEXIST;
 756                 goto out;
 757         }
 758
 759         if (IS_ERR(di)) {
 760                 ret = PTR_ERR(di);
 761                 goto out;
 762         }
 763
 764         if (subvol) {
 765                 ret = btrfs_mksubvol(&file->f_path, vol_args->name,
 766                                      file->f_path.dentry->d_inode->i_mode,
 767                                      namelen, NULL);
 768         } else {
 769                 struct inode *src_inode;
 770                 src_file = fget(vol_args->fd);
 771                 if (!src_file) {
 772                         ret = -EINVAL;
 773                         goto out;
 774                 }
 775
 776                 src_inode = src_file->f_path.dentry->d_inode;
 777                 if (src_inode->i_sb != file->f_path.dentry->d_inode->i_sb) {
 778                         printk(KERN_INFO "btrfs: Snapshot src from "
 779                                "another FS\n");
 780                         ret = -EINVAL;
 781                         fput(src_file);
 782                         goto out;
 783                 }
 784                 ret = btrfs_mksubvol(&file->f_path, vol_args->name,
 785                              file->f_path.dentry->d_inode->i_mode,
 786                              namelen, BTRFS_I(src_inode)->root);
 787                 fput(src_file);
 788         }
 789
 790 out:
 791         kfree(vol_args);
 792         return ret;
 793 }
 794
 795 static int btrfs_ioctl_defrag(struct file *file)
 796 {
 797         struct inode *inode = fdentry(file)->d_inode;
 798         struct btrfs_root *root = BTRFS_I(inode)->root;
 799         int ret;
 800
 801         ret = mnt_want_write(file->f_path.mnt);
 802         if (ret)
 803                 return ret;
 804
 805         switch (inode->i_mode & S_IFMT) {
 806         case S_IFDIR:
 807                 if (!capable(CAP_SYS_ADMIN)) {
 808                         ret = -EPERM;
 809                         goto out;
 810                 }
 811                 btrfs_defrag_root(root, 0);
 812                 btrfs_defrag_root(root->fs_info->extent_root, 0);
 813                 break;
 814         case S_IFREG:
 815                 if (!(file->f_mode & FMODE_WRITE)) {
 816                         ret = -EINVAL;
 817                         goto out;
 818                 }
 819                 btrfs_defrag_file(file);
 820                 break;
 821         }
 822 out:
 823         mnt_drop_write(file->f_path.mnt);
 824         return ret;
 825 }
 826
 827 static long btrfs_ioctl_add_dev(struct btrfs_root *root, void __user *arg)
 828 {
 829         struct btrfs_ioctl_vol_args *vol_args;
 830         int ret;
 831
 832         if (!capable(CAP_SYS_ADMIN))
 833                 return -EPERM;
 834
 835         vol_args = memdup_user(arg, sizeof(*vol_args));
 836         if (IS_ERR(vol_args))
 837                 return PTR_ERR(vol_args);
 838
 839         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
 840         ret = btrfs_init_new_device(root, vol_args->name);
 841
 842         kfree(vol_args);
 843         return ret;
 844 }
 845
 846 static long btrfs_ioctl_rm_dev(struct btrfs_root *root, void __user *arg)
 847 {
 848         struct btrfs_ioctl_vol_args *vol_args;
 849         int ret;
 850
 851         if (!capable(CAP_SYS_ADMIN))
 852                 return -EPERM;
 853
 854         if (root->fs_info->sb->s_flags & MS_RDONLY)
 855                 return -EROFS;
 856
 857         vol_args = memdup_user(arg, sizeof(*vol_args));
 858         if (IS_ERR(vol_args))
 859                 return PTR_ERR(vol_args);
 860
 861         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
 862         ret = btrfs_rm_device(root, vol_args->name);
 863
 864         kfree(vol_args);
 865         return ret;
 866 }
 867
 868 static long btrfs_ioctl_clone(struct file *file, unsigned long srcfd,
 869                 u64 off, u64 olen, u64 destoff)
 870 {
 871         struct inode *inode = fdentry(file)->d_inode;
 872         struct btrfs_root *root = BTRFS_I(inode)->root;
 873         struct file *src_file;
 874         struct inode *src;
 875         struct btrfs_trans_handle *trans;
 876         struct btrfs_path *path;
 877         struct extent_buffer *leaf;
 878         char *buf;
 879         struct btrfs_key key;
 880         u32 nritems;
 881         int slot;
 882         int ret;
 883         u64 len = olen;
 884         u64 bs = root->fs_info->sb->s_blocksize;
 885         u64 hint_byte;
 886
 887         /*
 888          * TODO:
 889          * - split compressed inline extents.  annoying: we need to
 890          *   decompress into destination's address_space (the file offset
 891          *   may change, so source mapping won't do), then recompress (or
 892          *   otherwise reinsert) a subrange.
 893          * - allow ranges within the same file to be cloned (provided
 894          *   they don't overlap)?
 895          */
 896
 897         /* the destination must be opened for writing */
 898         if (!(file->f_mode & FMODE_WRITE))
 899                 return -EINVAL;
 900
 901         ret = mnt_want_write(file->f_path.mnt);
 902         if (ret)
 903                 return ret;
 904
 905         src_file = fget(srcfd);
 906         if (!src_file) {
 907                 ret = -EBADF;
 908                 goto out_drop_write;
 909         }
 910         src = src_file->f_dentry->d_inode;
 911
 912         ret = -EINVAL;
 913         if (src == inode)
 914                 goto out_fput;
 915
 916         ret = -EISDIR;
 917         if (S_ISDIR(src->i_mode) || S_ISDIR(inode->i_mode))
 918                 goto out_fput;
 919
 920         ret = -EXDEV;
 921         if (src->i_sb != inode->i_sb || BTRFS_I(src)->root != root)
 922                 goto out_fput;
 923
 924         ret = -ENOMEM;
 925         buf = vmalloc(btrfs_level_size(root, 0));
 926         if (!buf)
 927                 goto out_fput;
 928
 929         path = btrfs_alloc_path();
 930         if (!path) {
 931                 vfree(buf);
 932                 goto out_fput;
 933         }
 934         path->reada = 2;
 935
 936         if (inode < src) {
 937                 mutex_lock(&inode->i_mutex);
 938                 mutex_lock(&src->i_mutex);
 939         } else {
 940                 mutex_lock(&src->i_mutex);
 941                 mutex_lock(&inode->i_mutex);
 942         }
 943
 944         /* determine range to clone */
 945         ret = -EINVAL;
 946         if (off >= src->i_size || off + len > src->i_size)
 947                 goto out_unlock;
 948         if (len == 0)
 949                 olen = len = src->i_size - off;
 950         /* if we extend to eof, continue to block boundary */
 951         if (off + len == src->i_size)
 952                 len = ((src->i_size + bs-1) & ~(bs-1))
 953                         - off;
 954
 955         /* verify the end result is block aligned */
 956         if ((off & (bs-1)) ||
 957             ((off + len) & (bs-1)))
 958                 goto out_unlock;
 959
 960         /* do any pending delalloc/csum calc on src, one way or
 961            another, and lock file content */
 962         while (1) {
 963                 struct btrfs_ordered_extent *ordered;
 964                 lock_extent(&BTRFS_I(src)->io_tree, off, off+len, GFP_NOFS);
 965                 ordered = btrfs_lookup_first_ordered_extent(inode, off+len);
 966                 if (BTRFS_I(src)->delalloc_bytes == 0 && !ordered)
 967                         break;
 968                 unlock_extent(&BTRFS_I(src)->io_tree, off, off+len, GFP_NOFS);
 969                 if (ordered)
 970                         btrfs_put_ordered_extent(ordered);
 971                 btrfs_wait_ordered_range(src, off, off+len);
 972         }
 973
 974         trans = btrfs_start_transaction(root, 1);
 975         BUG_ON(!trans);
 976
 977         /* punch hole in destination first */
 978         btrfs_drop_extents(trans, root, inode, off, off + len,
 979                            off + len, 0, &hint_byte);
 980
 981         /* clone data */
 982         key.objectid = src->i_ino;
 983         key.type = BTRFS_EXTENT_DATA_KEY;
 984         key.offset = 0;
 985
 986         while (1) {
 987                 /*
 988                  * note the key will change type as we walk through the
 989                  * tree.
 990                  */
 991                 ret = btrfs_search_slot(trans, root, &key, path, 0, 0);
 992                 if (ret < 0)
 993                         goto out;
 994
 995                 nritems = btrfs_header_nritems(path->nodes[0]);
 996                 if (path->slots[0] >= nritems) {
 997                         ret = btrfs_next_leaf(root, path);
 998                         if (ret < 0)
 999                                 goto out;
1000                         if (ret > 0)
1001                                 break;
1002                         nritems = btrfs_header_nritems(path->nodes[0]);
1003                 }
1004                 leaf = path->nodes[0];
1005                 slot = path->slots[0];
1006
1007                 btrfs_item_key_to_cpu(leaf, &key, slot);
1008                 if (btrfs_key_type(&key) > BTRFS_EXTENT_DATA_KEY ||
1009                     key.objectid != src->i_ino)
1010                         break;
1011
1012                 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) {
1013                         struct btrfs_file_extent_item *extent;
1014                         int type;
1015                         u32 size;
1016                         struct btrfs_key new_key;
1017                         u64 disko = 0, diskl = 0;
1018                         u64 datao = 0, datal = 0;
1019                         u8 comp;
1020
1021                         size = btrfs_item_size_nr(leaf, slot);
1022                         read_extent_buffer(leaf, buf,
1023                                            btrfs_item_ptr_offset(leaf, slot),
1024                                            size);
1025
1026                         extent = btrfs_item_ptr(leaf, slot,
1027                                                 struct btrfs_file_extent_item);
1028                         comp = btrfs_file_extent_compression(leaf, extent);
1029                         type = btrfs_file_extent_type(leaf, extent);
1030                         if (type == BTRFS_FILE_EXTENT_REG ||
1031                             type == BTRFS_FILE_EXTENT_PREALLOC) {
1032                                 disko = btrfs_file_extent_disk_bytenr(leaf,
1033                                                                       extent);
1034                                 diskl = btrfs_file_extent_disk_num_bytes(leaf,
1035                                                                  extent);
1036                                 datao = btrfs_file_extent_offset(leaf, extent);
1037                                 datal = btrfs_file_extent_num_bytes(leaf,
1038                                                                     extent);
1039                         } else if (type == BTRFS_FILE_EXTENT_INLINE) {
1040                                 /* take upper bound, may be compressed */
1041                                 datal = btrfs_file_extent_ram_bytes(leaf,
1042                                                                     extent);
1043                         }
1044                         btrfs_release_path(root, path);
1045
1046                         if (key.offset + datal < off ||
1047                             key.offset >= off+len)
1048                                 goto next;
1049
1050                         memcpy(&new_key, &key, sizeof(new_key));
1051                         new_key.objectid = inode->i_ino;
1052                         new_key.offset = key.offset + destoff - off;
1053
1054                         if (type == BTRFS_FILE_EXTENT_REG ||
1055                             type == BTRFS_FILE_EXTENT_PREALLOC) {
1056                                 ret = btrfs_insert_empty_item(trans, root, path,
1057                                                               &new_key, size);
1058                                 if (ret)
1059                                         goto out;
1060
1061                                 leaf = path->nodes[0];
1062                                 slot = path->slots[0];
1063                                 write_extent_buffer(leaf, buf,
1064                                             btrfs_item_ptr_offset(leaf, slot),
1065                                             size);
1066
1067                                 extent = btrfs_item_ptr(leaf, slot,
1068                                                 struct btrfs_file_extent_item);
1069
1070                                 if (off > key.offset) {
1071                                         datao += off - key.offset;
1072                                         datal -= off - key.offset;
1073                                 }
1074                                 if (key.offset + datao + datal + key.offset >
1075                                     off + len)
1076                                         datal = off + len - key.offset - datao;
1077                                 /* disko == 0 means it's a hole */
1078                                 if (!disko)
1079                                         datao = 0;
1080
1081                                 btrfs_set_file_extent_offset(leaf, extent,
1082                                                              datao);
1083                                 btrfs_set_file_extent_num_bytes(leaf, extent,
1084                                                                 datal);
1085                                 if (disko) {
1086                                         inode_add_bytes(inode, datal);
1087                                         ret = btrfs_inc_extent_ref(trans, root,
1088                                                         disko, diskl, 0,
1089                                                         root->root_key.objectid,
1090                                                         inode->i_ino,
1091                                                         new_key.offset - datao);
1092                                         BUG_ON(ret);
1093                                 }
1094                         } else if (type == BTRFS_FILE_EXTENT_INLINE) {
1095                                 u64 skip = 0;
1096                                 u64 trim = 0;
1097                                 if (off > key.offset) {
1098                                         skip = off - key.offset;
1099                                         new_key.offset += skip;
1100                                 }
1101
1102                                 if (key.offset + datal > off+len)
1103                                         trim = key.offset + datal - (off+len);
1104
1105                                 if (comp && (skip || trim)) {
1106                                         ret = -EINVAL;
1107                                         goto out;
1108                                 }
1109                                 size -= skip + trim;
1110                                 datal -= skip + trim;
1111                                 ret = btrfs_insert_empty_item(trans, root, path,
1112                                                               &new_key, size);
1113                                 if (ret)
1114                                         goto out;
1115
1116                                 if (skip) {
1117                                         u32 start =
1118                                           btrfs_file_extent_calc_inline_size(0);
1119                                         memmove(buf+start, buf+start+skip,
1120                                                 datal);
1121                                 }
1122
1123                                 leaf = path->nodes[0];
1124                                 slot = path->slots[0];
1125                                 write_extent_buffer(leaf, buf,
1126                                             btrfs_item_ptr_offset(leaf, slot),
1127                                             size);
1128                                 inode_add_bytes(inode, datal);
1129                         }
1130
1131                         btrfs_mark_buffer_dirty(leaf);
1132                 }
1133
1134 next:
1135                 btrfs_release_path(root, path);
1136                 key.offset++;
1137         }
1138         ret = 0;
1139 out:
1140         btrfs_release_path(root, path);
1141         if (ret == 0) {
1142                 inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1143                 if (destoff + olen > inode->i_size)
1144                         btrfs_i_size_write(inode, destoff + olen);
1145                 BTRFS_I(inode)->flags = BTRFS_I(src)->flags;
1146                 ret = btrfs_update_inode(trans, root, inode);
1147         }
1148         btrfs_end_transaction(trans, root);
1149         unlock_extent(&BTRFS_I(src)->io_tree, off, off+len, GFP_NOFS);
1150         if (ret)
1151                 vmtruncate(inode, 0);
1152 out_unlock:
1153         mutex_unlock(&src->i_mutex);
1154         mutex_unlock(&inode->i_mutex);
1155         vfree(buf);
1156         btrfs_free_path(path);
1157 out_fput:
1158         fput(src_file);
1159 out_drop_write:
1160         mnt_drop_write(file->f_path.mnt);
1161         return ret;
1162 }
1163
1164 static long btrfs_ioctl_clone_range(struct file *file, void __user *argp)
1165 {
1166         struct btrfs_ioctl_clone_range_args args;
1167
1168         if (copy_from_user(&args, argp, sizeof(args)))
1169                 return -EFAULT;
1170         return btrfs_ioctl_clone(file, args.src_fd, args.src_offset,
1171                                  args.src_length, args.dest_offset);
1172 }
1173
1174 /*
1175  * there are many ways the trans_start and trans_end ioctls can lead
1176  * to deadlocks.  They should only be used by applications that
1177  * basically own the machine, and have a very in depth understanding
1178  * of all the possible deadlocks and enospc problems.
1179  */
1180 static long btrfs_ioctl_trans_start(struct file *file)
1181 {
1182         struct inode *inode = fdentry(file)->d_inode;
1183         struct btrfs_root *root = BTRFS_I(inode)->root;
1184         struct btrfs_trans_handle *trans;
1185         int ret = 0;
1186
1187         if (!capable(CAP_SYS_ADMIN))
1188                 return -EPERM;
1189
1190         if (file->private_data) {
1191                 ret = -EINPROGRESS;
1192                 goto out;
1193         }
1194
1195         ret = mnt_want_write(file->f_path.mnt);
1196         if (ret)
1197                 goto out;
1198
1199         mutex_lock(&root->fs_info->trans_mutex);
1200         root->fs_info->open_ioctl_trans++;
1201         mutex_unlock(&root->fs_info->trans_mutex);
1202
1203         trans = btrfs_start_ioctl_transaction(root, 0);
1204         if (trans)
1205                 file->private_data = trans;
1206         else
1207                 ret = -ENOMEM;
1208         /*printk(KERN_INFO "btrfs_ioctl_trans_start on %p\n", file);*/
1209 out:
1210         return ret;
1211 }
1212
1213 /*
1214  * there are many ways the trans_start and trans_end ioctls can lead
1215  * to deadlocks.  They should only be used by applications that
1216  * basically own the machine, and have a very in depth understanding
1217  * of all the possible deadlocks and enospc problems.
1218  */
1219 long btrfs_ioctl_trans_end(struct file *file)
1220 {
1221         struct inode *inode = fdentry(file)->d_inode;
1222         struct btrfs_root *root = BTRFS_I(inode)->root;
1223         struct btrfs_trans_handle *trans;
1224         int ret = 0;
1225
1226         trans = file->private_data;
1227         if (!trans) {
1228                 ret = -EINVAL;
1229                 goto out;
1230         }
1231         btrfs_end_transaction(trans, root);
1232         file->private_data = NULL;
1233
1234         mutex_lock(&root->fs_info->trans_mutex);
1235         root->fs_info->open_ioctl_trans--;
1236         mutex_unlock(&root->fs_info->trans_mutex);
1237
1238         mnt_drop_write(file->f_path.mnt);
1239
1240 out:
1241         return ret;
1242 }
1243
1244 long btrfs_ioctl(struct file *file, unsigned int
1245                 cmd, unsigned long arg)
1246 {
1247         struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root;
1248         void __user *argp = (void __user *)arg;
1249
1250         switch (cmd) {
1251         case FS_IOC_GETFLAGS:
1252                 return btrfs_ioctl_getflags(file, argp);
1253         case FS_IOC_SETFLAGS:
1254                 return btrfs_ioctl_setflags(file, argp);
1255         case FS_IOC_GETVERSION:
1256                 return btrfs_ioctl_getversion(file, argp);
1257         case BTRFS_IOC_SNAP_CREATE:
1258                 return btrfs_ioctl_snap_create(file, argp, 0);
1259         case BTRFS_IOC_SUBVOL_CREATE:
1260                 return btrfs_ioctl_snap_create(file, argp, 1);
1261         case BTRFS_IOC_DEFRAG:
1262                 return btrfs_ioctl_defrag(file);
1263         case BTRFS_IOC_RESIZE:
1264                 return btrfs_ioctl_resize(root, argp);
1265         case BTRFS_IOC_ADD_DEV:
1266                 return btrfs_ioctl_add_dev(root, argp);
1267         case BTRFS_IOC_RM_DEV:
1268                 return btrfs_ioctl_rm_dev(root, argp);
1269         case BTRFS_IOC_BALANCE:
1270                 return btrfs_balance(root->fs_info->dev_root);
1271         case BTRFS_IOC_CLONE:
1272                 return btrfs_ioctl_clone(file, arg, 0, 0, 0);
1273         case BTRFS_IOC_CLONE_RANGE:
1274                 return btrfs_ioctl_clone_range(file, argp);
1275         case BTRFS_IOC_TRANS_START:
1276                 return btrfs_ioctl_trans_start(file);
1277         case BTRFS_IOC_TRANS_END:
1278                 return btrfs_ioctl_trans_end(file);
1279         case BTRFS_IOC_SYNC:
1280                 btrfs_sync_fs(file->f_dentry->d_sb, 1);
1281                 return 0;
1282         }
1283
1284         return -ENOTTY;
1285 }