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 <linux/slab.h>
  43 #include "compat.h"
  44 #include "ctree.h"
  45 #include "disk-io.h"
  46 #include "transaction.h"
  47 #include "btrfs_inode.h"
  48 #include "ioctl.h"
  49 #include "print-tree.h"
  50 #include "volumes.h"
  51 #include "locking.h"
  52
  53 /* Mask out flags that are inappropriate for the given type of inode. */
  54 static inline __u32 btrfs_mask_flags(umode_t mode, __u32 flags)
  55 {
  56         if (S_ISDIR(mode))
  57                 return flags;
  58         else if (S_ISREG(mode))
  59                 return flags & ~FS_DIRSYNC_FL;
  60         else
  61                 return flags & (FS_NODUMP_FL | FS_NOATIME_FL);
  62 }
  63
  64 /*
  65  * Export inode flags to the format expected by the FS_IOC_GETFLAGS ioctl.
  66  */
  67 static unsigned int btrfs_flags_to_ioctl(unsigned int flags)
  68 {
  69         unsigned int iflags = 0;
  70
  71         if (flags & BTRFS_INODE_SYNC)
  72                 iflags |= FS_SYNC_FL;
  73         if (flags & BTRFS_INODE_IMMUTABLE)
  74                 iflags |= FS_IMMUTABLE_FL;
  75         if (flags & BTRFS_INODE_APPEND)
  76                 iflags |= FS_APPEND_FL;
  77         if (flags & BTRFS_INODE_NODUMP)
  78                 iflags |= FS_NODUMP_FL;
  79         if (flags & BTRFS_INODE_NOATIME)
  80                 iflags |= FS_NOATIME_FL;
  81         if (flags & BTRFS_INODE_DIRSYNC)
  82                 iflags |= FS_DIRSYNC_FL;
  83
  84         return iflags;
  85 }
  86
  87 /*
  88  * Update inode->i_flags based on the btrfs internal flags.
  89  */
  90 void btrfs_update_iflags(struct inode *inode)
  91 {
  92         struct btrfs_inode *ip = BTRFS_I(inode);
  93
  94         inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
  95
  96         if (ip->flags & BTRFS_INODE_SYNC)
  97                 inode->i_flags |= S_SYNC;
  98         if (ip->flags & BTRFS_INODE_IMMUTABLE)
  99                 inode->i_flags |= S_IMMUTABLE;
 100         if (ip->flags & BTRFS_INODE_APPEND)
 101                 inode->i_flags |= S_APPEND;
 102         if (ip->flags & BTRFS_INODE_NOATIME)
 103                 inode->i_flags |= S_NOATIME;
 104         if (ip->flags & BTRFS_INODE_DIRSYNC)
 105                 inode->i_flags |= S_DIRSYNC;
 106 }
 107
 108 /*
 109  * Inherit flags from the parent inode.
 110  *
 111  * Unlike extN we don't have any flags we don't want to inherit currently.
 112  */
 113 void btrfs_inherit_iflags(struct inode *inode, struct inode *dir)
 114 {
 115         unsigned int flags;
 116
 117         if (!dir)
 118                 return;
 119
 120         flags = BTRFS_I(dir)->flags;
 121
 122         if (S_ISREG(inode->i_mode))
 123                 flags &= ~BTRFS_INODE_DIRSYNC;
 124         else if (!S_ISDIR(inode->i_mode))
 125                 flags &= (BTRFS_INODE_NODUMP | BTRFS_INODE_NOATIME);
 126
 127         BTRFS_I(inode)->flags = flags;
 128         btrfs_update_iflags(inode);
 129 }
 130
 131 static int btrfs_ioctl_getflags(struct file *file, void __user *arg)
 132 {
 133         struct btrfs_inode *ip = BTRFS_I(file->f_path.dentry->d_inode);
 134         unsigned int flags = btrfs_flags_to_ioctl(ip->flags);
 135
 136         if (copy_to_user(arg, &flags, sizeof(flags)))
 137                 return -EFAULT;
 138         return 0;
 139 }
 140
 141 static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
 142 {
 143         struct inode *inode = file->f_path.dentry->d_inode;
 144         struct btrfs_inode *ip = BTRFS_I(inode);
 145         struct btrfs_root *root = ip->root;
 146         struct btrfs_trans_handle *trans;
 147         unsigned int flags, oldflags;
 148         int ret;
 149
 150         if (copy_from_user(&flags, arg, sizeof(flags)))
 151                 return -EFAULT;
 152
 153         if (flags & ~(FS_IMMUTABLE_FL | FS_APPEND_FL | \
 154                       FS_NOATIME_FL | FS_NODUMP_FL | \
 155                       FS_SYNC_FL | FS_DIRSYNC_FL))
 156                 return -EOPNOTSUPP;
 157
 158         if (!is_owner_or_cap(inode))
 159                 return -EACCES;
 160
 161         mutex_lock(&inode->i_mutex);
 162
 163         flags = btrfs_mask_flags(inode->i_mode, flags);
 164         oldflags = btrfs_flags_to_ioctl(ip->flags);
 165         if ((flags ^ oldflags) & (FS_APPEND_FL | FS_IMMUTABLE_FL)) {
 166                 if (!capable(CAP_LINUX_IMMUTABLE)) {
 167                         ret = -EPERM;
 168                         goto out_unlock;
 169                 }
 170         }
 171
 172         ret = mnt_want_write(file->f_path.mnt);
 173         if (ret)
 174                 goto out_unlock;
 175
 176         if (flags & FS_SYNC_FL)
 177                 ip->flags |= BTRFS_INODE_SYNC;
 178         else
 179                 ip->flags &= ~BTRFS_INODE_SYNC;
 180         if (flags & FS_IMMUTABLE_FL)
 181                 ip->flags |= BTRFS_INODE_IMMUTABLE;
 182         else
 183                 ip->flags &= ~BTRFS_INODE_IMMUTABLE;
 184         if (flags & FS_APPEND_FL)
 185                 ip->flags |= BTRFS_INODE_APPEND;
 186         else
 187                 ip->flags &= ~BTRFS_INODE_APPEND;
 188         if (flags & FS_NODUMP_FL)
 189                 ip->flags |= BTRFS_INODE_NODUMP;
 190         else
 191                 ip->flags &= ~BTRFS_INODE_NODUMP;
 192         if (flags & FS_NOATIME_FL)
 193                 ip->flags |= BTRFS_INODE_NOATIME;
 194         else
 195                 ip->flags &= ~BTRFS_INODE_NOATIME;
 196         if (flags & FS_DIRSYNC_FL)
 197                 ip->flags |= BTRFS_INODE_DIRSYNC;
 198         else
 199                 ip->flags &= ~BTRFS_INODE_DIRSYNC;
 200
 201
 202         trans = btrfs_join_transaction(root, 1);
 203         BUG_ON(!trans);
 204
 205         ret = btrfs_update_inode(trans, root, inode);
 206         BUG_ON(ret);
 207
 208         btrfs_update_iflags(inode);
 209         inode->i_ctime = CURRENT_TIME;
 210         btrfs_end_transaction(trans, root);
 211
 212         mnt_drop_write(file->f_path.mnt);
 213  out_unlock:
 214         mutex_unlock(&inode->i_mutex);
 215         return 0;
 216 }
 217
 218 static int btrfs_ioctl_getversion(struct file *file, int __user *arg)
 219 {
 220         struct inode *inode = file->f_path.dentry->d_inode;
 221
 222         return put_user(inode->i_generation, arg);
 223 }
 224
 225 static noinline int create_subvol(struct btrfs_root *root,
 226                                   struct dentry *dentry,
 227                                   char *name, int namelen,
 228                                   u64 *async_transid)
 229 {
 230         struct btrfs_trans_handle *trans;
 231         struct btrfs_key key;
 232         struct btrfs_root_item root_item;
 233         struct btrfs_inode_item *inode_item;
 234         struct extent_buffer *leaf;
 235         struct btrfs_root *new_root;
 236         struct dentry *parent = dget_parent(dentry);
 237         struct inode *dir;
 238         int ret;
 239         int err;
 240         u64 objectid;
 241         u64 new_dirid = BTRFS_FIRST_FREE_OBJECTID;
 242         u64 index = 0;
 243
 244         ret = btrfs_find_free_objectid(NULL, root->fs_info->tree_root,
 245                                        0, &objectid);
 246         if (ret) {
 247                 dput(parent);
 248                 return ret;
 249         }
 250
 251         dir = parent->d_inode;
 252
 253         /*
 254          * 1 - inode item
 255          * 2 - refs
 256          * 1 - root item
 257          * 2 - dir items
 258          */
 259         trans = btrfs_start_transaction(root, 6);
 260         if (IS_ERR(trans)) {
 261                 dput(parent);
 262                 return PTR_ERR(trans);
 263         }
 264
 265         leaf = btrfs_alloc_free_block(trans, root, root->leafsize,
 266                                       0, objectid, NULL, 0, 0, 0);
 267         if (IS_ERR(leaf)) {
 268                 ret = PTR_ERR(leaf);
 269                 goto fail;
 270         }
 271
 272         memset_extent_buffer(leaf, 0, 0, sizeof(struct btrfs_header));
 273         btrfs_set_header_bytenr(leaf, leaf->start);
 274         btrfs_set_header_generation(leaf, trans->transid);
 275         btrfs_set_header_backref_rev(leaf, BTRFS_MIXED_BACKREF_REV);
 276         btrfs_set_header_owner(leaf, objectid);
 277
 278         write_extent_buffer(leaf, root->fs_info->fsid,
 279                             (unsigned long)btrfs_header_fsid(leaf),
 280                             BTRFS_FSID_SIZE);
 281         write_extent_buffer(leaf, root->fs_info->chunk_tree_uuid,
 282                             (unsigned long)btrfs_header_chunk_tree_uuid(leaf),
 283                             BTRFS_UUID_SIZE);
 284         btrfs_mark_buffer_dirty(leaf);
 285
 286         inode_item = &root_item.inode;
 287         memset(inode_item, 0, sizeof(*inode_item));
 288         inode_item->generation = cpu_to_le64(1);
 289         inode_item->size = cpu_to_le64(3);
 290         inode_item->nlink = cpu_to_le32(1);
 291         inode_item->nbytes = cpu_to_le64(root->leafsize);
 292         inode_item->mode = cpu_to_le32(S_IFDIR | 0755);
 293
 294         btrfs_set_root_bytenr(&root_item, leaf->start);
 295         btrfs_set_root_generation(&root_item, trans->transid);
 296         btrfs_set_root_level(&root_item, 0);
 297         btrfs_set_root_refs(&root_item, 1);
 298         btrfs_set_root_used(&root_item, leaf->len);
 299         btrfs_set_root_last_snapshot(&root_item, 0);
 300
 301         memset(&root_item.drop_progress, 0, sizeof(root_item.drop_progress));
 302         root_item.drop_level = 0;
 303
 304         btrfs_tree_unlock(leaf);
 305         free_extent_buffer(leaf);
 306         leaf = NULL;
 307
 308         btrfs_set_root_dirid(&root_item, new_dirid);
 309
 310         key.objectid = objectid;
 311         key.offset = 0;
 312         btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
 313         ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key,
 314                                 &root_item);
 315         if (ret)
 316                 goto fail;
 317
 318         key.offset = (u64)-1;
 319         new_root = btrfs_read_fs_root_no_name(root->fs_info, &key);
 320         BUG_ON(IS_ERR(new_root));
 321
 322         btrfs_record_root_in_trans(trans, new_root);
 323
 324         ret = btrfs_create_subvol_root(trans, new_root, new_dirid,
 325                                        BTRFS_I(dir)->block_group);
 326         /*
 327          * insert the directory item
 328          */
 329         ret = btrfs_set_inode_index(dir, &index);
 330         BUG_ON(ret);
 331
 332         ret = btrfs_insert_dir_item(trans, root,
 333                                     name, namelen, dir->i_ino, &key,
 334                                     BTRFS_FT_DIR, index);
 335         if (ret)
 336                 goto fail;
 337
 338         btrfs_i_size_write(dir, dir->i_size + namelen * 2);
 339         ret = btrfs_update_inode(trans, root, dir);
 340         BUG_ON(ret);
 341
 342         ret = btrfs_add_root_ref(trans, root->fs_info->tree_root,
 343                                  objectid, root->root_key.objectid,
 344                                  dir->i_ino, index, name, namelen);
 345
 346         BUG_ON(ret);
 347
 348         d_instantiate(dentry, btrfs_lookup_dentry(dir, dentry));
 349 fail:
 350         dput(parent);
 351         if (async_transid) {
 352                 *async_transid = trans->transid;
 353                 err = btrfs_commit_transaction_async(trans, root, 1);
 354         } else {
 355                 err = btrfs_commit_transaction(trans, root);
 356         }
 357         if (err && !ret)
 358                 ret = err;
 359         return ret;
 360 }
 361
 362 static int create_snapshot(struct btrfs_root *root, struct dentry *dentry,
 363                            char *name, int namelen, u64 *async_transid)
 364 {
 365         struct inode *inode;
 366         struct dentry *parent;
 367         struct btrfs_pending_snapshot *pending_snapshot;
 368         struct btrfs_trans_handle *trans;
 369         int ret;
 370
 371         if (!root->ref_cows)
 372                 return -EINVAL;
 373
 374         pending_snapshot = kzalloc(sizeof(*pending_snapshot), GFP_NOFS);
 375         if (!pending_snapshot)
 376                 return -ENOMEM;
 377
 378         btrfs_init_block_rsv(&pending_snapshot->block_rsv);
 379         pending_snapshot->dentry = dentry;
 380         pending_snapshot->root = root;
 381
 382         trans = btrfs_start_transaction(root->fs_info->extent_root, 5);
 383         if (IS_ERR(trans)) {
 384                 ret = PTR_ERR(trans);
 385                 goto fail;
 386         }
 387
 388         ret = btrfs_snap_reserve_metadata(trans, pending_snapshot);
 389         BUG_ON(ret);
 390
 391         list_add(&pending_snapshot->list,
 392                  &trans->transaction->pending_snapshots);
 393         if (async_transid) {
 394                 *async_transid = trans->transid;
 395                 ret = btrfs_commit_transaction_async(trans,
 396                                      root->fs_info->extent_root, 1);
 397         } else {
 398                 ret = btrfs_commit_transaction(trans,
 399                                                root->fs_info->extent_root);
 400         }
 401         BUG_ON(ret);
 402
 403         ret = pending_snapshot->error;
 404         if (ret)
 405                 goto fail;
 406
 407         btrfs_orphan_cleanup(pending_snapshot->snap);
 408
 409         parent = dget_parent(dentry);
 410         inode = btrfs_lookup_dentry(parent->d_inode, dentry);
 411         dput(parent);
 412         if (IS_ERR(inode)) {
 413                 ret = PTR_ERR(inode);
 414                 goto fail;
 415         }
 416         BUG_ON(!inode);
 417         d_instantiate(dentry, inode);
 418         ret = 0;
 419 fail:
 420         kfree(pending_snapshot);
 421         return ret;
 422 }
 423
 424 /*  copy of check_sticky in fs/namei.c()
 425 * It's inline, so penalty for filesystems that don't use sticky bit is
 426 * minimal.
 427 */
 428 static inline int btrfs_check_sticky(struct inode *dir, struct inode *inode)
 429 {
 430         uid_t fsuid = current_fsuid();
 431
 432         if (!(dir->i_mode & S_ISVTX))
 433                 return 0;
 434         if (inode->i_uid == fsuid)
 435                 return 0;
 436         if (dir->i_uid == fsuid)
 437                 return 0;
 438         return !capable(CAP_FOWNER);
 439 }
 440
 441 /*  copy of may_delete in fs/namei.c()
 442  *      Check whether we can remove a link victim from directory dir, check
 443  *  whether the type of victim is right.
 444  *  1. We can't do it if dir is read-only (done in permission())
 445  *  2. We should have write and exec permissions on dir
 446  *  3. We can't remove anything from append-only dir
 447  *  4. We can't do anything with immutable dir (done in permission())
 448  *  5. If the sticky bit on dir is set we should either
 449  *      a. be owner of dir, or
 450  *      b. be owner of victim, or
 451  *      c. have CAP_FOWNER capability
 452  *  6. If the victim is append-only or immutable we can't do antyhing with
 453  *     links pointing to it.
 454  *  7. If we were asked to remove a directory and victim isn't one - ENOTDIR.
 455  *  8. If we were asked to remove a non-directory and victim isn't one - EISDIR.
 456  *  9. We can't remove a root or mountpoint.
 457  * 10. We don't allow removal of NFS sillyrenamed files; it's handled by
 458  *     nfs_async_unlink().
 459  */
 460
 461 static int btrfs_may_delete(struct inode *dir,struct dentry *victim,int isdir)
 462 {
 463         int error;
 464
 465         if (!victim->d_inode)
 466                 return -ENOENT;
 467
 468         BUG_ON(victim->d_parent->d_inode != dir);
 469         audit_inode_child(victim, dir);
 470
 471         error = inode_permission(dir, MAY_WRITE | MAY_EXEC);
 472         if (error)
 473                 return error;
 474         if (IS_APPEND(dir))
 475                 return -EPERM;
 476         if (btrfs_check_sticky(dir, victim->d_inode)||
 477                 IS_APPEND(victim->d_inode)||
 478             IS_IMMUTABLE(victim->d_inode) || IS_SWAPFILE(victim->d_inode))
 479                 return -EPERM;
 480         if (isdir) {
 481                 if (!S_ISDIR(victim->d_inode->i_mode))
 482                         return -ENOTDIR;
 483                 if (IS_ROOT(victim))
 484                         return -EBUSY;
 485         } else if (S_ISDIR(victim->d_inode->i_mode))
 486                 return -EISDIR;
 487         if (IS_DEADDIR(dir))
 488                 return -ENOENT;
 489         if (victim->d_flags & DCACHE_NFSFS_RENAMED)
 490                 return -EBUSY;
 491         return 0;
 492 }
 493
 494 /* copy of may_create in fs/namei.c() */
 495 static inline int btrfs_may_create(struct inode *dir, struct dentry *child)
 496 {
 497         if (child->d_inode)
 498                 return -EEXIST;
 499         if (IS_DEADDIR(dir))
 500                 return -ENOENT;
 501         return inode_permission(dir, MAY_WRITE | MAY_EXEC);
 502 }
 503
 504 /*
 505  * Create a new subvolume below @parent.  This is largely modeled after
 506  * sys_mkdirat and vfs_mkdir, but we only do a single component lookup
 507  * inside this filesystem so it's quite a bit simpler.
 508  */
 509 static noinline int btrfs_mksubvol(struct path *parent,
 510                                    char *name, int namelen,
 511                                    struct btrfs_root *snap_src,
 512                                    u64 *async_transid)
 513 {
 514         struct inode *dir  = parent->dentry->d_inode;
 515         struct dentry *dentry;
 516         int error;
 517
 518         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 519
 520         dentry = lookup_one_len(name, parent->dentry, namelen);
 521         error = PTR_ERR(dentry);
 522         if (IS_ERR(dentry))
 523                 goto out_unlock;
 524
 525         error = -EEXIST;
 526         if (dentry->d_inode)
 527                 goto out_dput;
 528
 529         error = mnt_want_write(parent->mnt);
 530         if (error)
 531                 goto out_dput;
 532
 533         error = btrfs_may_create(dir, dentry);
 534         if (error)
 535                 goto out_drop_write;
 536
 537         down_read(&BTRFS_I(dir)->root->fs_info->subvol_sem);
 538
 539         if (btrfs_root_refs(&BTRFS_I(dir)->root->root_item) == 0)
 540                 goto out_up_read;
 541
 542         if (snap_src) {
 543                 error = create_snapshot(snap_src, dentry,
 544                                         name, namelen, async_transid);
 545         } else {
 546                 error = create_subvol(BTRFS_I(dir)->root, dentry,
 547                                       name, namelen, async_transid);
 548         }
 549         if (!error)
 550                 fsnotify_mkdir(dir, dentry);
 551 out_up_read:
 552         up_read(&BTRFS_I(dir)->root->fs_info->subvol_sem);
 553 out_drop_write:
 554         mnt_drop_write(parent->mnt);
 555 out_dput:
 556         dput(dentry);
 557 out_unlock:
 558         mutex_unlock(&dir->i_mutex);
 559         return error;
 560 }
 561
 562 static int should_defrag_range(struct inode *inode, u64 start, u64 len,
 563                                int thresh, u64 *last_len, u64 *skip,
 564                                u64 *defrag_end)
 565 {
 566         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
 567         struct extent_map *em = NULL;
 568         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 569         int ret = 1;
 570
 571
 572         if (thresh == 0)
 573                 thresh = 256 * 1024;
 574
 575         /*
 576          * make sure that once we start defragging and extent, we keep on
 577          * defragging it
 578          */
 579         if (start < *defrag_end)
 580                 return 1;
 581
 582         *skip = 0;
 583
 584         /*
 585          * hopefully we have this extent in the tree already, try without
 586          * the full extent lock
 587          */
 588         read_lock(&em_tree->lock);
 589         em = lookup_extent_mapping(em_tree, start, len);
 590         read_unlock(&em_tree->lock);
 591
 592         if (!em) {
 593                 /* get the big lock and read metadata off disk */
 594                 lock_extent(io_tree, start, start + len - 1, GFP_NOFS);
 595                 em = btrfs_get_extent(inode, NULL, 0, start, len, 0);
 596                 unlock_extent(io_tree, start, start + len - 1, GFP_NOFS);
 597
 598                 if (IS_ERR(em))
 599                         return 0;
 600         }
 601
 602         /* this will cover holes, and inline extents */
 603         if (em->block_start >= EXTENT_MAP_LAST_BYTE)
 604                 ret = 0;
 605
 606         /*
 607          * we hit a real extent, if it is big don't bother defragging it again
 608          */
 609         if ((*last_len == 0 || *last_len >= thresh) && em->len >= thresh)
 610                 ret = 0;
 611
 612         /*
 613          * last_len ends up being a counter of how many bytes we've defragged.
 614          * every time we choose not to defrag an extent, we reset *last_len
 615          * so that the next tiny extent will force a defrag.
 616          *
 617          * The end result of this is that tiny extents before a single big
 618          * extent will force at least part of that big extent to be defragged.
 619          */
 620         if (ret) {
 621                 *last_len += len;
 622                 *defrag_end = extent_map_end(em);
 623         } else {
 624                 *last_len = 0;
 625                 *skip = extent_map_end(em);
 626                 *defrag_end = 0;
 627         }
 628
 629         free_extent_map(em);
 630         return ret;
 631 }
 632
 633 static int btrfs_defrag_file(struct file *file,
 634                              struct btrfs_ioctl_defrag_range_args *range)
 635 {
 636         struct inode *inode = fdentry(file)->d_inode;
 637         struct btrfs_root *root = BTRFS_I(inode)->root;
 638         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
 639         struct btrfs_ordered_extent *ordered;
 640         struct page *page;
 641         unsigned long last_index;
 642         unsigned long ra_pages = root->fs_info->bdi.ra_pages;
 643         unsigned long total_read = 0;
 644         u64 page_start;
 645         u64 page_end;
 646         u64 last_len = 0;
 647         u64 skip = 0;
 648         u64 defrag_end = 0;
 649         unsigned long i;
 650         int ret;
 651
 652         if (inode->i_size == 0)
 653                 return 0;
 654
 655         if (range->start + range->len > range->start) {
 656                 last_index = min_t(u64, inode->i_size - 1,
 657                          range->start + range->len - 1) >> PAGE_CACHE_SHIFT;
 658         } else {
 659                 last_index = (inode->i_size - 1) >> PAGE_CACHE_SHIFT;
 660         }
 661
 662         i = range->start >> PAGE_CACHE_SHIFT;
 663         while (i <= last_index) {
 664                 if (!should_defrag_range(inode, (u64)i << PAGE_CACHE_SHIFT,
 665                                         PAGE_CACHE_SIZE,
 666                                         range->extent_thresh,
 667                                         &last_len, &skip,
 668                                         &defrag_end)) {
 669                         unsigned long next;
 670                         /*
 671                          * the should_defrag function tells us how much to skip
 672                          * bump our counter by the suggested amount
 673                          */
 674                         next = (skip + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
 675                         i = max(i + 1, next);
 676                         continue;
 677                 }
 678
 679                 if (total_read % ra_pages == 0) {
 680                         btrfs_force_ra(inode->i_mapping, &file->f_ra, file, i,
 681                                        min(last_index, i + ra_pages - 1));
 682                 }
 683                 total_read++;
 684                 mutex_lock(&inode->i_mutex);
 685                 if (range->flags & BTRFS_DEFRAG_RANGE_COMPRESS)
 686                         BTRFS_I(inode)->force_compress = 1;
 687
 688                 ret  = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE);
 689                 if (ret)
 690                         goto err_unlock;
 691 again:
 692                 if (inode->i_size == 0 ||
 693                     i > ((inode->i_size - 1) >> PAGE_CACHE_SHIFT)) {
 694                         ret = 0;
 695                         goto err_reservations;
 696                 }
 697
 698                 page = grab_cache_page(inode->i_mapping, i);
 699                 if (!page) {
 700                         ret = -ENOMEM;
 701                         goto err_reservations;
 702                 }
 703
 704                 if (!PageUptodate(page)) {
 705                         btrfs_readpage(NULL, page);
 706                         lock_page(page);
 707                         if (!PageUptodate(page)) {
 708                                 unlock_page(page);
 709                                 page_cache_release(page);
 710                                 ret = -EIO;
 711                                 goto err_reservations;
 712                         }
 713                 }
 714
 715                 if (page->mapping != inode->i_mapping) {
 716                         unlock_page(page);
 717                         page_cache_release(page);
 718                         goto again;
 719                 }
 720
 721                 wait_on_page_writeback(page);
 722
 723                 if (PageDirty(page)) {
 724                         btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
 725                         goto loop_unlock;
 726                 }
 727
 728                 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
 729                 page_end = page_start + PAGE_CACHE_SIZE - 1;
 730                 lock_extent(io_tree, page_start, page_end, GFP_NOFS);
 731
 732                 ordered = btrfs_lookup_ordered_extent(inode, page_start);
 733                 if (ordered) {
 734                         unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
 735                         unlock_page(page);
 736                         page_cache_release(page);
 737                         btrfs_start_ordered_extent(inode, ordered, 1);
 738                         btrfs_put_ordered_extent(ordered);
 739                         goto again;
 740                 }
 741                 set_page_extent_mapped(page);
 742
 743                 /*
 744                  * this makes sure page_mkwrite is called on the
 745                  * page if it is dirtied again later
 746                  */
 747                 clear_page_dirty_for_io(page);
 748                 clear_extent_bits(&BTRFS_I(inode)->io_tree, page_start,
 749                                   page_end, EXTENT_DIRTY | EXTENT_DELALLOC |
 750                                   EXTENT_DO_ACCOUNTING, GFP_NOFS);
 751
 752                 btrfs_set_extent_delalloc(inode, page_start, page_end, NULL);
 753                 ClearPageChecked(page);
 754                 set_page_dirty(page);
 755                 unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
 756
 757 loop_unlock:
 758                 unlock_page(page);
 759                 page_cache_release(page);
 760                 mutex_unlock(&inode->i_mutex);
 761
 762                 balance_dirty_pages_ratelimited_nr(inode->i_mapping, 1);
 763                 i++;
 764         }
 765
 766         if ((range->flags & BTRFS_DEFRAG_RANGE_START_IO))
 767                 filemap_flush(inode->i_mapping);
 768
 769         if ((range->flags & BTRFS_DEFRAG_RANGE_COMPRESS)) {
 770                 /* the filemap_flush will queue IO into the worker threads, but
 771                  * we have to make sure the IO is actually started and that
 772                  * ordered extents get created before we return
 773                  */
 774                 atomic_inc(&root->fs_info->async_submit_draining);
 775                 while (atomic_read(&root->fs_info->nr_async_submits) ||
 776                       atomic_read(&root->fs_info->async_delalloc_pages)) {
 777                         wait_event(root->fs_info->async_submit_wait,
 778                            (atomic_read(&root->fs_info->nr_async_submits) == 0 &&
 779                             atomic_read(&root->fs_info->async_delalloc_pages) == 0));
 780                 }
 781                 atomic_dec(&root->fs_info->async_submit_draining);
 782
 783                 mutex_lock(&inode->i_mutex);
 784                 BTRFS_I(inode)->force_compress = 0;
 785                 mutex_unlock(&inode->i_mutex);
 786         }
 787
 788         return 0;
 789
 790 err_reservations:
 791         btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
 792 err_unlock:
 793         mutex_unlock(&inode->i_mutex);
 794         return ret;
 795 }
 796
 797 static noinline int btrfs_ioctl_resize(struct btrfs_root *root,
 798                                         void __user *arg)
 799 {
 800         u64 new_size;
 801         u64 old_size;
 802         u64 devid = 1;
 803         struct btrfs_ioctl_vol_args *vol_args;
 804         struct btrfs_trans_handle *trans;
 805         struct btrfs_device *device = NULL;
 806         char *sizestr;
 807         char *devstr = NULL;
 808         int ret = 0;
 809         int mod = 0;
 810
 811         if (root->fs_info->sb->s_flags & MS_RDONLY)
 812                 return -EROFS;
 813
 814         if (!capable(CAP_SYS_ADMIN))
 815                 return -EPERM;
 816
 817         vol_args = memdup_user(arg, sizeof(*vol_args));
 818         if (IS_ERR(vol_args))
 819                 return PTR_ERR(vol_args);
 820
 821         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
 822
 823         mutex_lock(&root->fs_info->volume_mutex);
 824         sizestr = vol_args->name;
 825         devstr = strchr(sizestr, ':');
 826         if (devstr) {
 827                 char *end;
 828                 sizestr = devstr + 1;
 829                 *devstr = '\0';
 830                 devstr = vol_args->name;
 831                 devid = simple_strtoull(devstr, &end, 10);
 832                 printk(KERN_INFO "resizing devid %llu\n",
 833                        (unsigned long long)devid);
 834         }
 835         device = btrfs_find_device(root, devid, NULL, NULL);
 836         if (!device) {
 837                 printk(KERN_INFO "resizer unable to find device %llu\n",
 838                        (unsigned long long)devid);
 839                 ret = -EINVAL;
 840                 goto out_unlock;
 841         }
 842         if (!strcmp(sizestr, "max"))
 843                 new_size = device->bdev->bd_inode->i_size;
 844         else {
 845                 if (sizestr[0] == '-') {
 846                         mod = -1;
 847                         sizestr++;
 848                 } else if (sizestr[0] == '+') {
 849                         mod = 1;
 850                         sizestr++;
 851                 }
 852                 new_size = memparse(sizestr, NULL);
 853                 if (new_size == 0) {
 854                         ret = -EINVAL;
 855                         goto out_unlock;
 856                 }
 857         }
 858
 859         old_size = device->total_bytes;
 860
 861         if (mod < 0) {
 862                 if (new_size > old_size) {
 863                         ret = -EINVAL;
 864                         goto out_unlock;
 865                 }
 866                 new_size = old_size - new_size;
 867         } else if (mod > 0) {
 868                 new_size = old_size + new_size;
 869         }
 870
 871         if (new_size < 256 * 1024 * 1024) {
 872                 ret = -EINVAL;
 873                 goto out_unlock;
 874         }
 875         if (new_size > device->bdev->bd_inode->i_size) {
 876                 ret = -EFBIG;
 877                 goto out_unlock;
 878         }
 879
 880         do_div(new_size, root->sectorsize);
 881         new_size *= root->sectorsize;
 882
 883         printk(KERN_INFO "new size for %s is %llu\n",
 884                 device->name, (unsigned long long)new_size);
 885
 886         if (new_size > old_size) {
 887                 trans = btrfs_start_transaction(root, 0);
 888                 ret = btrfs_grow_device(trans, device, new_size);
 889                 btrfs_commit_transaction(trans, root);
 890         } else {
 891                 ret = btrfs_shrink_device(device, new_size);
 892         }
 893
 894 out_unlock:
 895         mutex_unlock(&root->fs_info->volume_mutex);
 896         kfree(vol_args);
 897         return ret;
 898 }
 899
 900 static noinline int btrfs_ioctl_snap_create_transid(struct file *file,
 901                                                     char *name,
 902                                                     unsigned long fd,
 903                                                     int subvol,
 904                                                     u64 *transid)
 905 {
 906         struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root;
 907         struct file *src_file;
 908         int namelen;
 909         int ret = 0;
 910
 911         if (root->fs_info->sb->s_flags & MS_RDONLY)
 912                 return -EROFS;
 913
 914         namelen = strlen(name);
 915         if (strchr(name, '/')) {
 916                 ret = -EINVAL;
 917                 goto out;
 918         }
 919
 920         if (subvol) {
 921                 ret = btrfs_mksubvol(&file->f_path, name, namelen,
 922                                      NULL, transid);
 923         } else {
 924                 struct inode *src_inode;
 925                 src_file = fget(fd);
 926                 if (!src_file) {
 927                         ret = -EINVAL;
 928                         goto out;
 929                 }
 930
 931                 src_inode = src_file->f_path.dentry->d_inode;
 932                 if (src_inode->i_sb != file->f_path.dentry->d_inode->i_sb) {
 933                         printk(KERN_INFO "btrfs: Snapshot src from "
 934                                "another FS\n");
 935                         ret = -EINVAL;
 936                         fput(src_file);
 937                         goto out;
 938                 }
 939                 ret = btrfs_mksubvol(&file->f_path, name, namelen,
 940                                      BTRFS_I(src_inode)->root,
 941                                      transid);
 942                 fput(src_file);
 943         }
 944 out:
 945         return ret;
 946 }
 947
 948 static noinline int btrfs_ioctl_snap_create(struct file *file,
 949                                             void __user *arg, int subvol,
 950                                             int v2)
 951 {
 952         struct btrfs_ioctl_vol_args *vol_args = NULL;
 953         struct btrfs_ioctl_vol_args_v2 *vol_args_v2 = NULL;
 954         char *name;
 955         u64 fd;
 956         int ret;
 957
 958         if (v2) {
 959                 u64 transid = 0;
 960                 u64 *ptr = NULL;
 961
 962                 vol_args_v2 = memdup_user(arg, sizeof(*vol_args_v2));
 963                 if (IS_ERR(vol_args_v2))
 964                         return PTR_ERR(vol_args_v2);
 965
 966                 if (vol_args_v2->flags & ~BTRFS_SUBVOL_CREATE_ASYNC) {
 967                         ret = -EINVAL;
 968                         goto out;
 969                 }
 970
 971                 name = vol_args_v2->name;
 972                 fd = vol_args_v2->fd;
 973                 vol_args_v2->name[BTRFS_SUBVOL_NAME_MAX] = '\0';
 974
 975                 if (vol_args_v2->flags & BTRFS_SUBVOL_CREATE_ASYNC)
 976                         ptr = &transid;
 977
 978                 ret = btrfs_ioctl_snap_create_transid(file, name, fd,
 979                                                       subvol, ptr);
 980
 981                 if (ret == 0 && ptr &&
 982                     copy_to_user(arg +
 983                                  offsetof(struct btrfs_ioctl_vol_args_v2,
 984                                           transid), ptr, sizeof(*ptr)))
 985                         ret = -EFAULT;
 986         } else {
 987                 vol_args = memdup_user(arg, sizeof(*vol_args));
 988                 if (IS_ERR(vol_args))
 989                         return PTR_ERR(vol_args);
 990                 name = vol_args->name;
 991                 fd = vol_args->fd;
 992                 vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
 993
 994                 ret = btrfs_ioctl_snap_create_transid(file, name, fd,
 995                                                       subvol, NULL);
 996         }
 997 out:
 998         kfree(vol_args);
 999         kfree(vol_args_v2);
1000
1001         return ret;
1002 }
1003
1004 /*
1005  * helper to check if the subvolume references other subvolumes
1006  */
1007 static noinline int may_destroy_subvol(struct btrfs_root *root)
1008 {
1009         struct btrfs_path *path;
1010         struct btrfs_key key;
1011         int ret;
1012
1013         path = btrfs_alloc_path();
1014         if (!path)
1015                 return -ENOMEM;
1016
1017         key.objectid = root->root_key.objectid;
1018         key.type = BTRFS_ROOT_REF_KEY;
1019         key.offset = (u64)-1;
1020
1021         ret = btrfs_search_slot(NULL, root->fs_info->tree_root,
1022                                 &key, path, 0, 0);
1023         if (ret < 0)
1024                 goto out;
1025         BUG_ON(ret == 0);
1026
1027         ret = 0;
1028         if (path->slots[0] > 0) {
1029                 path->slots[0]--;
1030                 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1031                 if (key.objectid == root->root_key.objectid &&
1032                     key.type == BTRFS_ROOT_REF_KEY)
1033                         ret = -ENOTEMPTY;
1034         }
1035 out:
1036         btrfs_free_path(path);
1037         return ret;
1038 }
1039
1040 static noinline int key_in_sk(struct btrfs_key *key,
1041                               struct btrfs_ioctl_search_key *sk)
1042 {
1043         struct btrfs_key test;
1044         int ret;
1045
1046         test.objectid = sk->min_objectid;
1047         test.type = sk->min_type;
1048         test.offset = sk->min_offset;
1049
1050         ret = btrfs_comp_cpu_keys(key, &test);
1051         if (ret < 0)
1052                 return 0;
1053
1054         test.objectid = sk->max_objectid;
1055         test.type = sk->max_type;
1056         test.offset = sk->max_offset;
1057
1058         ret = btrfs_comp_cpu_keys(key, &test);
1059         if (ret > 0)
1060                 return 0;
1061         return 1;
1062 }
1063
1064 static noinline int copy_to_sk(struct btrfs_root *root,
1065                                struct btrfs_path *path,
1066                                struct btrfs_key *key,
1067                                struct btrfs_ioctl_search_key *sk,
1068                                char *buf,
1069                                unsigned long *sk_offset,
1070                                int *num_found)
1071 {
1072         u64 found_transid;
1073         struct extent_buffer *leaf;
1074         struct btrfs_ioctl_search_header sh;
1075         unsigned long item_off;
1076         unsigned long item_len;
1077         int nritems;
1078         int i;
1079         int slot;
1080         int found = 0;
1081         int ret = 0;
1082
1083         leaf = path->nodes[0];
1084         slot = path->slots[0];
1085         nritems = btrfs_header_nritems(leaf);
1086
1087         if (btrfs_header_generation(leaf) > sk->max_transid) {
1088                 i = nritems;
1089                 goto advance_key;
1090         }
1091         found_transid = btrfs_header_generation(leaf);
1092
1093         for (i = slot; i < nritems; i++) {
1094                 item_off = btrfs_item_ptr_offset(leaf, i);
1095                 item_len = btrfs_item_size_nr(leaf, i);
1096
1097                 if (item_len > BTRFS_SEARCH_ARGS_BUFSIZE)
1098                         item_len = 0;
1099
1100                 if (sizeof(sh) + item_len + *sk_offset >
1101                     BTRFS_SEARCH_ARGS_BUFSIZE) {
1102                         ret = 1;
1103                         goto overflow;
1104                 }
1105
1106                 btrfs_item_key_to_cpu(leaf, key, i);
1107                 if (!key_in_sk(key, sk))
1108                         continue;
1109
1110                 sh.objectid = key->objectid;
1111                 sh.offset = key->offset;
1112                 sh.type = key->type;
1113                 sh.len = item_len;
1114                 sh.transid = found_transid;
1115
1116                 /* copy search result header */
1117                 memcpy(buf + *sk_offset, &sh, sizeof(sh));
1118                 *sk_offset += sizeof(sh);
1119
1120                 if (item_len) {
1121                         char *p = buf + *sk_offset;
1122                         /* copy the item */
1123                         read_extent_buffer(leaf, p,
1124                                            item_off, item_len);
1125                         *sk_offset += item_len;
1126                 }
1127                 found++;
1128
1129                 if (*num_found >= sk->nr_items)
1130                         break;
1131         }
1132 advance_key:
1133         ret = 0;
1134         if (key->offset < (u64)-1 && key->offset < sk->max_offset)
1135                 key->offset++;
1136         else if (key->type < (u8)-1 && key->type < sk->max_type) {
1137                 key->offset = 0;
1138                 key->type++;
1139         } else if (key->objectid < (u64)-1 && key->objectid < sk->max_objectid) {
1140                 key->offset = 0;
1141                 key->type = 0;
1142                 key->objectid++;
1143         } else
1144                 ret = 1;
1145 overflow:
1146         *num_found += found;
1147         return ret;
1148 }
1149
1150 static noinline int search_ioctl(struct inode *inode,
1151                                  struct btrfs_ioctl_search_args *args)
1152 {
1153         struct btrfs_root *root;
1154         struct btrfs_key key;
1155         struct btrfs_key max_key;
1156         struct btrfs_path *path;
1157         struct btrfs_ioctl_search_key *sk = &args->key;
1158         struct btrfs_fs_info *info = BTRFS_I(inode)->root->fs_info;
1159         int ret;
1160         int num_found = 0;
1161         unsigned long sk_offset = 0;
1162
1163         path = btrfs_alloc_path();
1164         if (!path)
1165                 return -ENOMEM;
1166
1167         if (sk->tree_id == 0) {
1168                 /* search the root of the inode that was passed */
1169                 root = BTRFS_I(inode)->root;
1170         } else {
1171                 key.objectid = sk->tree_id;
1172                 key.type = BTRFS_ROOT_ITEM_KEY;
1173                 key.offset = (u64)-1;
1174                 root = btrfs_read_fs_root_no_name(info, &key);
1175                 if (IS_ERR(root)) {
1176                         printk(KERN_ERR "could not find root %llu\n",
1177                                sk->tree_id);
1178                         btrfs_free_path(path);
1179                         return -ENOENT;
1180                 }
1181         }
1182
1183         key.objectid = sk->min_objectid;
1184         key.type = sk->min_type;
1185         key.offset = sk->min_offset;
1186
1187         max_key.objectid = sk->max_objectid;
1188         max_key.type = sk->max_type;
1189         max_key.offset = sk->max_offset;
1190
1191         path->keep_locks = 1;
1192
1193         while(1) {
1194                 ret = btrfs_search_forward(root, &key, &max_key, path, 0,
1195                                            sk->min_transid);
1196                 if (ret != 0) {
1197                         if (ret > 0)
1198                                 ret = 0;
1199                         goto err;
1200                 }
1201                 ret = copy_to_sk(root, path, &key, sk, args->buf,
1202                                  &sk_offset, &num_found);
1203                 btrfs_release_path(root, path);
1204                 if (ret || num_found >= sk->nr_items)
1205                         break;
1206
1207         }
1208         ret = 0;
1209 err:
1210         sk->nr_items = num_found;
1211         btrfs_free_path(path);
1212         return ret;
1213 }
1214
1215 static noinline int btrfs_ioctl_tree_search(struct file *file,
1216                                            void __user *argp)
1217 {
1218          struct btrfs_ioctl_search_args *args;
1219          struct inode *inode;
1220          int ret;
1221
1222         if (!capable(CAP_SYS_ADMIN))
1223                 return -EPERM;
1224
1225         args = memdup_user(argp, sizeof(*args));
1226         if (IS_ERR(args))
1227                 return PTR_ERR(args);
1228
1229         inode = fdentry(file)->d_inode;
1230         ret = search_ioctl(inode, args);
1231         if (ret == 0 && copy_to_user(argp, args, sizeof(*args)))
1232                 ret = -EFAULT;
1233         kfree(args);
1234         return ret;
1235 }
1236
1237 /*
1238  * Search INODE_REFs to identify path name of 'dirid' directory
1239  * in a 'tree_id' tree. and sets path name to 'name'.
1240  */
1241 static noinline int btrfs_search_path_in_tree(struct btrfs_fs_info *info,
1242                                 u64 tree_id, u64 dirid, char *name)
1243 {
1244         struct btrfs_root *root;
1245         struct btrfs_key key;
1246         char *ptr;
1247         int ret = -1;
1248         int slot;
1249         int len;
1250         int total_len = 0;
1251         struct btrfs_inode_ref *iref;
1252         struct extent_buffer *l;
1253         struct btrfs_path *path;
1254
1255         if (dirid == BTRFS_FIRST_FREE_OBJECTID) {
1256                 name[0]='\0';
1257                 return 0;
1258         }
1259
1260         path = btrfs_alloc_path();
1261         if (!path)
1262                 return -ENOMEM;
1263
1264         ptr = &name[BTRFS_INO_LOOKUP_PATH_MAX];
1265
1266         key.objectid = tree_id;
1267         key.type = BTRFS_ROOT_ITEM_KEY;
1268         key.offset = (u64)-1;
1269         root = btrfs_read_fs_root_no_name(info, &key);
1270         if (IS_ERR(root)) {
1271                 printk(KERN_ERR "could not find root %llu\n", tree_id);
1272                 ret = -ENOENT;
1273                 goto out;
1274         }
1275
1276         key.objectid = dirid;
1277         key.type = BTRFS_INODE_REF_KEY;
1278         key.offset = (u64)-1;
1279
1280         while(1) {
1281                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1282                 if (ret < 0)
1283                         goto out;
1284
1285                 l = path->nodes[0];
1286                 slot = path->slots[0];
1287                 if (ret > 0 && slot > 0)
1288                         slot--;
1289                 btrfs_item_key_to_cpu(l, &key, slot);
1290
1291                 if (ret > 0 && (key.objectid != dirid ||
1292                                 key.type != BTRFS_INODE_REF_KEY)) {
1293                         ret = -ENOENT;
1294                         goto out;
1295                 }
1296
1297                 iref = btrfs_item_ptr(l, slot, struct btrfs_inode_ref);
1298                 len = btrfs_inode_ref_name_len(l, iref);
1299                 ptr -= len + 1;
1300                 total_len += len + 1;
1301                 if (ptr < name)
1302                         goto out;
1303
1304                 *(ptr + len) = '/';
1305                 read_extent_buffer(l, ptr,(unsigned long)(iref + 1), len);
1306
1307                 if (key.offset == BTRFS_FIRST_FREE_OBJECTID)
1308                         break;
1309
1310                 btrfs_release_path(root, path);
1311                 key.objectid = key.offset;
1312                 key.offset = (u64)-1;
1313                 dirid = key.objectid;
1314
1315         }
1316         if (ptr < name)
1317                 goto out;
1318         memcpy(name, ptr, total_len);
1319         name[total_len]='\0';
1320         ret = 0;
1321 out:
1322         btrfs_free_path(path);
1323         return ret;
1324 }
1325
1326 static noinline int btrfs_ioctl_ino_lookup(struct file *file,
1327                                            void __user *argp)
1328 {
1329          struct btrfs_ioctl_ino_lookup_args *args;
1330          struct inode *inode;
1331          int ret;
1332
1333         if (!capable(CAP_SYS_ADMIN))
1334                 return -EPERM;
1335
1336         args = memdup_user(argp, sizeof(*args));
1337         if (IS_ERR(args))
1338                 return PTR_ERR(args);
1339
1340         inode = fdentry(file)->d_inode;
1341
1342         if (args->treeid == 0)
1343                 args->treeid = BTRFS_I(inode)->root->root_key.objectid;
1344
1345         ret = btrfs_search_path_in_tree(BTRFS_I(inode)->root->fs_info,
1346                                         args->treeid, args->objectid,
1347                                         args->name);
1348
1349         if (ret == 0 && copy_to_user(argp, args, sizeof(*args)))
1350                 ret = -EFAULT;
1351
1352         kfree(args);
1353         return ret;
1354 }
1355
1356 static noinline int btrfs_ioctl_snap_destroy(struct file *file,
1357                                              void __user *arg)
1358 {
1359         struct dentry *parent = fdentry(file);
1360         struct dentry *dentry;
1361         struct inode *dir = parent->d_inode;
1362         struct inode *inode;
1363         struct btrfs_root *root = BTRFS_I(dir)->root;
1364         struct btrfs_root *dest = NULL;
1365         struct btrfs_ioctl_vol_args *vol_args;
1366         struct btrfs_trans_handle *trans;
1367         int namelen;
1368         int ret;
1369         int err = 0;
1370
1371         vol_args = memdup_user(arg, sizeof(*vol_args));
1372         if (IS_ERR(vol_args))
1373                 return PTR_ERR(vol_args);
1374
1375         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
1376         namelen = strlen(vol_args->name);
1377         if (strchr(vol_args->name, '/') ||
1378             strncmp(vol_args->name, "..", namelen) == 0) {
1379                 err = -EINVAL;
1380                 goto out;
1381         }
1382
1383         err = mnt_want_write(file->f_path.mnt);
1384         if (err)
1385                 goto out;
1386
1387         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
1388         dentry = lookup_one_len(vol_args->name, parent, namelen);
1389         if (IS_ERR(dentry)) {
1390                 err = PTR_ERR(dentry);
1391                 goto out_unlock_dir;
1392         }
1393
1394         if (!dentry->d_inode) {
1395                 err = -ENOENT;
1396                 goto out_dput;
1397         }
1398
1399         inode = dentry->d_inode;
1400         dest = BTRFS_I(inode)->root;
1401         if (!capable(CAP_SYS_ADMIN)){
1402                 /*
1403                  * Regular user.  Only allow this with a special mount
1404                  * option, when the user has write+exec access to the
1405                  * subvol root, and when rmdir(2) would have been
1406                  * allowed.
1407                  *
1408                  * Note that this is _not_ check that the subvol is
1409                  * empty or doesn't contain data that we wouldn't
1410                  * otherwise be able to delete.
1411                  *
1412                  * Users who want to delete empty subvols should try
1413                  * rmdir(2).
1414                  */
1415                 err = -EPERM;
1416                 if (!btrfs_test_opt(root, USER_SUBVOL_RM_ALLOWED))
1417                         goto out_dput;
1418
1419                 /*
1420                  * Do not allow deletion if the parent dir is the same
1421                  * as the dir to be deleted.  That means the ioctl
1422                  * must be called on the dentry referencing the root
1423                  * of the subvol, not a random directory contained
1424                  * within it.
1425                  */
1426                 err = -EINVAL;
1427                 if (root == dest)
1428                         goto out_dput;
1429
1430                 err = inode_permission(inode, MAY_WRITE | MAY_EXEC);
1431                 if (err)
1432                         goto out_dput;
1433
1434                 /* check if subvolume may be deleted by a non-root user */
1435                 err = btrfs_may_delete(dir, dentry, 1);
1436                 if (err)
1437                         goto out_dput;
1438         }
1439
1440         if (inode->i_ino != BTRFS_FIRST_FREE_OBJECTID) {
1441                 err = -EINVAL;
1442                 goto out_dput;
1443         }
1444
1445         mutex_lock(&inode->i_mutex);
1446         err = d_invalidate(dentry);
1447         if (err)
1448                 goto out_unlock;
1449
1450         down_write(&root->fs_info->subvol_sem);
1451
1452         err = may_destroy_subvol(dest);
1453         if (err)
1454                 goto out_up_write;
1455
1456         trans = btrfs_start_transaction(root, 0);
1457         if (IS_ERR(trans)) {
1458                 err = PTR_ERR(trans);
1459                 goto out_up_write;
1460         }
1461         trans->block_rsv = &root->fs_info->global_block_rsv;
1462
1463         ret = btrfs_unlink_subvol(trans, root, dir,
1464                                 dest->root_key.objectid,
1465                                 dentry->d_name.name,
1466                                 dentry->d_name.len);
1467         BUG_ON(ret);
1468
1469         btrfs_record_root_in_trans(trans, dest);
1470
1471         memset(&dest->root_item.drop_progress, 0,
1472                 sizeof(dest->root_item.drop_progress));
1473         dest->root_item.drop_level = 0;
1474         btrfs_set_root_refs(&dest->root_item, 0);
1475
1476         if (!xchg(&dest->orphan_item_inserted, 1)) {
1477                 ret = btrfs_insert_orphan_item(trans,
1478                                         root->fs_info->tree_root,
1479                                         dest->root_key.objectid);
1480                 BUG_ON(ret);
1481         }
1482
1483         ret = btrfs_end_transaction(trans, root);
1484         BUG_ON(ret);
1485         inode->i_flags |= S_DEAD;
1486 out_up_write:
1487         up_write(&root->fs_info->subvol_sem);
1488 out_unlock:
1489         mutex_unlock(&inode->i_mutex);
1490         if (!err) {
1491                 shrink_dcache_sb(root->fs_info->sb);
1492                 btrfs_invalidate_inodes(dest);
1493                 d_delete(dentry);
1494         }
1495 out_dput:
1496         dput(dentry);
1497 out_unlock_dir:
1498         mutex_unlock(&dir->i_mutex);
1499         mnt_drop_write(file->f_path.mnt);
1500 out:
1501         kfree(vol_args);
1502         return err;
1503 }
1504
1505 static int btrfs_ioctl_defrag(struct file *file, void __user *argp)
1506 {
1507         struct inode *inode = fdentry(file)->d_inode;
1508         struct btrfs_root *root = BTRFS_I(inode)->root;
1509         struct btrfs_ioctl_defrag_range_args *range;
1510         int ret;
1511
1512         ret = mnt_want_write(file->f_path.mnt);
1513         if (ret)
1514                 return ret;
1515
1516         switch (inode->i_mode & S_IFMT) {
1517         case S_IFDIR:
1518                 if (!capable(CAP_SYS_ADMIN)) {
1519                         ret = -EPERM;
1520                         goto out;
1521                 }
1522                 ret = btrfs_defrag_root(root, 0);
1523                 if (ret)
1524                         goto out;
1525                 ret = btrfs_defrag_root(root->fs_info->extent_root, 0);
1526                 break;
1527         case S_IFREG:
1528                 if (!(file->f_mode & FMODE_WRITE)) {
1529                         ret = -EINVAL;
1530                         goto out;
1531                 }
1532
1533                 range = kzalloc(sizeof(*range), GFP_KERNEL);
1534                 if (!range) {
1535                         ret = -ENOMEM;
1536                         goto out;
1537                 }
1538
1539                 if (argp) {
1540                         if (copy_from_user(range, argp,
1541                                            sizeof(*range))) {
1542                                 ret = -EFAULT;
1543                                 kfree(range);
1544                                 goto out;
1545                         }
1546                         /* compression requires us to start the IO */
1547                         if ((range->flags & BTRFS_DEFRAG_RANGE_COMPRESS)) {
1548                                 range->flags |= BTRFS_DEFRAG_RANGE_START_IO;
1549                                 range->extent_thresh = (u32)-1;
1550                         }
1551                 } else {
1552                         /* the rest are all set to zero by kzalloc */
1553                         range->len = (u64)-1;
1554                 }
1555                 ret = btrfs_defrag_file(file, range);
1556                 kfree(range);
1557                 break;
1558         default:
1559                 ret = -EINVAL;
1560         }
1561 out:
1562         mnt_drop_write(file->f_path.mnt);
1563         return ret;
1564 }
1565
1566 static long btrfs_ioctl_add_dev(struct btrfs_root *root, void __user *arg)
1567 {
1568         struct btrfs_ioctl_vol_args *vol_args;
1569         int ret;
1570
1571         if (!capable(CAP_SYS_ADMIN))
1572                 return -EPERM;
1573
1574         vol_args = memdup_user(arg, sizeof(*vol_args));
1575         if (IS_ERR(vol_args))
1576                 return PTR_ERR(vol_args);
1577
1578         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
1579         ret = btrfs_init_new_device(root, vol_args->name);
1580
1581         kfree(vol_args);
1582         return ret;
1583 }
1584
1585 static long btrfs_ioctl_rm_dev(struct btrfs_root *root, void __user *arg)
1586 {
1587         struct btrfs_ioctl_vol_args *vol_args;
1588         int ret;
1589
1590         if (!capable(CAP_SYS_ADMIN))
1591                 return -EPERM;
1592
1593         if (root->fs_info->sb->s_flags & MS_RDONLY)
1594                 return -EROFS;
1595
1596         vol_args = memdup_user(arg, sizeof(*vol_args));
1597         if (IS_ERR(vol_args))
1598                 return PTR_ERR(vol_args);
1599
1600         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
1601         ret = btrfs_rm_device(root, vol_args->name);
1602
1603         kfree(vol_args);
1604         return ret;
1605 }
1606
1607 static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd,
1608                                        u64 off, u64 olen, u64 destoff)
1609 {
1610         struct inode *inode = fdentry(file)->d_inode;
1611         struct btrfs_root *root = BTRFS_I(inode)->root;
1612         struct file *src_file;
1613         struct inode *src;
1614         struct btrfs_trans_handle *trans;
1615         struct btrfs_path *path;
1616         struct extent_buffer *leaf;
1617         char *buf;
1618         struct btrfs_key key;
1619         u32 nritems;
1620         int slot;
1621         int ret;
1622         u64 len = olen;
1623         u64 bs = root->fs_info->sb->s_blocksize;
1624         u64 hint_byte;
1625
1626         /*
1627          * TODO:
1628          * - split compressed inline extents.  annoying: we need to
1629          *   decompress into destination's address_space (the file offset
1630          *   may change, so source mapping won't do), then recompress (or
1631          *   otherwise reinsert) a subrange.
1632          * - allow ranges within the same file to be cloned (provided
1633          *   they don't overlap)?
1634          */
1635
1636         /* the destination must be opened for writing */
1637         if (!(file->f_mode & FMODE_WRITE) || (file->f_flags & O_APPEND))
1638                 return -EINVAL;
1639
1640         ret = mnt_want_write(file->f_path.mnt);
1641         if (ret)
1642                 return ret;
1643
1644         src_file = fget(srcfd);
1645         if (!src_file) {
1646                 ret = -EBADF;
1647                 goto out_drop_write;
1648         }
1649
1650         src = src_file->f_dentry->d_inode;
1651
1652         ret = -EINVAL;
1653         if (src == inode)
1654                 goto out_fput;
1655
1656         /* the src must be open for reading */
1657         if (!(src_file->f_mode & FMODE_READ))
1658                 goto out_fput;
1659
1660         ret = -EISDIR;
1661         if (S_ISDIR(src->i_mode) || S_ISDIR(inode->i_mode))
1662                 goto out_fput;
1663
1664         ret = -EXDEV;
1665         if (src->i_sb != inode->i_sb || BTRFS_I(src)->root != root)
1666                 goto out_fput;
1667
1668         ret = -ENOMEM;
1669         buf = vmalloc(btrfs_level_size(root, 0));
1670         if (!buf)
1671                 goto out_fput;
1672
1673         path = btrfs_alloc_path();
1674         if (!path) {
1675                 vfree(buf);
1676                 goto out_fput;
1677         }
1678         path->reada = 2;
1679
1680         if (inode < src) {
1681                 mutex_lock_nested(&inode->i_mutex, I_MUTEX_PARENT);
1682                 mutex_lock_nested(&src->i_mutex, I_MUTEX_CHILD);
1683         } else {
1684                 mutex_lock_nested(&src->i_mutex, I_MUTEX_PARENT);
1685                 mutex_lock_nested(&inode->i_mutex, I_MUTEX_CHILD);
1686         }
1687
1688         /* determine range to clone */
1689         ret = -EINVAL;
1690         if (off + len > src->i_size || off + len < off)
1691                 goto out_unlock;
1692         if (len == 0)
1693                 olen = len = src->i_size - off;
1694         /* if we extend to eof, continue to block boundary */
1695         if (off + len == src->i_size)
1696                 len = ALIGN(src->i_size, bs) - off;
1697
1698         /* verify the end result is block aligned */
1699         if (!IS_ALIGNED(off, bs) || !IS_ALIGNED(off + len, bs) ||
1700             !IS_ALIGNED(destoff, bs))
1701                 goto out_unlock;
1702
1703         /* do any pending delalloc/csum calc on src, one way or
1704            another, and lock file content */
1705         while (1) {
1706                 struct btrfs_ordered_extent *ordered;
1707                 lock_extent(&BTRFS_I(src)->io_tree, off, off+len, GFP_NOFS);
1708                 ordered = btrfs_lookup_first_ordered_extent(src, off+len);
1709                 if (!ordered &&
1710                     !test_range_bit(&BTRFS_I(src)->io_tree, off, off+len,
1711                                    EXTENT_DELALLOC, 0, NULL))
1712                         break;
1713                 unlock_extent(&BTRFS_I(src)->io_tree, off, off+len, GFP_NOFS);
1714                 if (ordered)
1715                         btrfs_put_ordered_extent(ordered);
1716                 btrfs_wait_ordered_range(src, off, len);
1717         }
1718
1719         /* clone data */
1720         key.objectid = src->i_ino;
1721         key.type = BTRFS_EXTENT_DATA_KEY;
1722         key.offset = 0;
1723
1724         while (1) {
1725                 /*
1726                  * note the key will change type as we walk through the
1727                  * tree.
1728                  */
1729                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1730                 if (ret < 0)
1731                         goto out;
1732
1733                 nritems = btrfs_header_nritems(path->nodes[0]);
1734                 if (path->slots[0] >= nritems) {
1735                         ret = btrfs_next_leaf(root, path);
1736                         if (ret < 0)
1737                                 goto out;
1738                         if (ret > 0)
1739                                 break;
1740                         nritems = btrfs_header_nritems(path->nodes[0]);
1741                 }
1742                 leaf = path->nodes[0];
1743                 slot = path->slots[0];
1744
1745                 btrfs_item_key_to_cpu(leaf, &key, slot);
1746                 if (btrfs_key_type(&key) > BTRFS_EXTENT_DATA_KEY ||
1747                     key.objectid != src->i_ino)
1748                         break;
1749
1750                 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) {
1751                         struct btrfs_file_extent_item *extent;
1752                         int type;
1753                         u32 size;
1754                         struct btrfs_key new_key;
1755                         u64 disko = 0, diskl = 0;
1756                         u64 datao = 0, datal = 0;
1757                         u8 comp;
1758                         u64 endoff;
1759
1760                         size = btrfs_item_size_nr(leaf, slot);
1761                         read_extent_buffer(leaf, buf,
1762                                            btrfs_item_ptr_offset(leaf, slot),
1763                                            size);
1764
1765                         extent = btrfs_item_ptr(leaf, slot,
1766                                                 struct btrfs_file_extent_item);
1767                         comp = btrfs_file_extent_compression(leaf, extent);
1768                         type = btrfs_file_extent_type(leaf, extent);
1769                         if (type == BTRFS_FILE_EXTENT_REG ||
1770                             type == BTRFS_FILE_EXTENT_PREALLOC) {
1771                                 disko = btrfs_file_extent_disk_bytenr(leaf,
1772                                                                       extent);
1773                                 diskl = btrfs_file_extent_disk_num_bytes(leaf,
1774                                                                  extent);
1775                                 datao = btrfs_file_extent_offset(leaf, extent);
1776                                 datal = btrfs_file_extent_num_bytes(leaf,
1777                                                                     extent);
1778                         } else if (type == BTRFS_FILE_EXTENT_INLINE) {
1779                                 /* take upper bound, may be compressed */
1780                                 datal = btrfs_file_extent_ram_bytes(leaf,
1781                                                                     extent);
1782                         }
1783                         btrfs_release_path(root, path);
1784
1785                         if (key.offset + datal <= off ||
1786                             key.offset >= off+len)
1787                                 goto next;
1788
1789                         memcpy(&new_key, &key, sizeof(new_key));
1790                         new_key.objectid = inode->i_ino;
1791                         new_key.offset = key.offset + destoff - off;
1792
1793                         trans = btrfs_start_transaction(root, 1);
1794                         if (IS_ERR(trans)) {
1795                                 ret = PTR_ERR(trans);
1796                                 goto out;
1797                         }
1798
1799                         if (type == BTRFS_FILE_EXTENT_REG ||
1800                             type == BTRFS_FILE_EXTENT_PREALLOC) {
1801                                 if (off > key.offset) {
1802                                         datao += off - key.offset;
1803                                         datal -= off - key.offset;
1804                                 }
1805
1806                                 if (key.offset + datal > off + len)
1807                                         datal = off + len - key.offset;
1808
1809                                 ret = btrfs_drop_extents(trans, inode,
1810                                                          new_key.offset,
1811                                                          new_key.offset + datal,
1812                                                          &hint_byte, 1);
1813                                 BUG_ON(ret);
1814
1815                                 ret = btrfs_insert_empty_item(trans, root, path,
1816                                                               &new_key, size);
1817                                 BUG_ON(ret);
1818
1819                                 leaf = path->nodes[0];
1820                                 slot = path->slots[0];
1821                                 write_extent_buffer(leaf, buf,
1822                                             btrfs_item_ptr_offset(leaf, slot),
1823                                             size);
1824
1825                                 extent = btrfs_item_ptr(leaf, slot,
1826                                                 struct btrfs_file_extent_item);
1827
1828                                 /* disko == 0 means it's a hole */
1829                                 if (!disko)
1830                                         datao = 0;
1831
1832                                 btrfs_set_file_extent_offset(leaf, extent,
1833                                                              datao);
1834                                 btrfs_set_file_extent_num_bytes(leaf, extent,
1835                                                                 datal);
1836                                 if (disko) {
1837                                         inode_add_bytes(inode, datal);
1838                                         ret = btrfs_inc_extent_ref(trans, root,
1839                                                         disko, diskl, 0,
1840                                                         root->root_key.objectid,
1841                                                         inode->i_ino,
1842                                                         new_key.offset - datao);
1843                                         BUG_ON(ret);
1844                                 }
1845                         } else if (type == BTRFS_FILE_EXTENT_INLINE) {
1846                                 u64 skip = 0;
1847                                 u64 trim = 0;
1848                                 if (off > key.offset) {
1849                                         skip = off - key.offset;
1850                                         new_key.offset += skip;
1851                                 }
1852
1853                                 if (key.offset + datal > off+len)
1854                                         trim = key.offset + datal - (off+len);
1855
1856                                 if (comp && (skip || trim)) {
1857                                         ret = -EINVAL;
1858                                         btrfs_end_transaction(trans, root);
1859                                         goto out;
1860                                 }
1861                                 size -= skip + trim;
1862                                 datal -= skip + trim;
1863
1864                                 ret = btrfs_drop_extents(trans, inode,
1865                                                          new_key.offset,
1866                                                          new_key.offset + datal,
1867                                                          &hint_byte, 1);
1868                                 BUG_ON(ret);
1869
1870                                 ret = btrfs_insert_empty_item(trans, root, path,
1871                                                               &new_key, size);
1872                                 BUG_ON(ret);
1873
1874                                 if (skip) {
1875                                         u32 start =
1876                                           btrfs_file_extent_calc_inline_size(0);
1877                                         memmove(buf+start, buf+start+skip,
1878                                                 datal);
1879                                 }
1880
1881                                 leaf = path->nodes[0];
1882                                 slot = path->slots[0];
1883                                 write_extent_buffer(leaf, buf,
1884                                             btrfs_item_ptr_offset(leaf, slot),
1885                                             size);
1886                                 inode_add_bytes(inode, datal);
1887                         }
1888
1889                         btrfs_mark_buffer_dirty(leaf);
1890                         btrfs_release_path(root, path);
1891
1892                         inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1893
1894                         /*
1895                          * we round up to the block size at eof when
1896                          * determining which extents to clone above,
1897                          * but shouldn't round up the file size
1898                          */
1899                         endoff = new_key.offset + datal;
1900                         if (endoff > destoff+olen)
1901                                 endoff = destoff+olen;
1902                         if (endoff > inode->i_size)
1903                                 btrfs_i_size_write(inode, endoff);
1904
1905                         BTRFS_I(inode)->flags = BTRFS_I(src)->flags;
1906                         ret = btrfs_update_inode(trans, root, inode);
1907                         BUG_ON(ret);
1908                         btrfs_end_transaction(trans, root);
1909                 }
1910 next:
1911                 btrfs_release_path(root, path);
1912                 key.offset++;
1913         }
1914         ret = 0;
1915 out:
1916         btrfs_release_path(root, path);
1917         unlock_extent(&BTRFS_I(src)->io_tree, off, off+len, GFP_NOFS);
1918 out_unlock:
1919         mutex_unlock(&src->i_mutex);
1920         mutex_unlock(&inode->i_mutex);
1921         vfree(buf);
1922         btrfs_free_path(path);
1923 out_fput:
1924         fput(src_file);
1925 out_drop_write:
1926         mnt_drop_write(file->f_path.mnt);
1927         return ret;
1928 }
1929
1930 static long btrfs_ioctl_clone_range(struct file *file, void __user *argp)
1931 {
1932         struct btrfs_ioctl_clone_range_args args;
1933
1934         if (copy_from_user(&args, argp, sizeof(args)))
1935                 return -EFAULT;
1936         return btrfs_ioctl_clone(file, args.src_fd, args.src_offset,
1937                                  args.src_length, args.dest_offset);
1938 }
1939
1940 /*
1941  * there are many ways the trans_start and trans_end ioctls can lead
1942  * to deadlocks.  They should only be used by applications that
1943  * basically own the machine, and have a very in depth understanding
1944  * of all the possible deadlocks and enospc problems.
1945  */
1946 static long btrfs_ioctl_trans_start(struct file *file)
1947 {
1948         struct inode *inode = fdentry(file)->d_inode;
1949         struct btrfs_root *root = BTRFS_I(inode)->root;
1950         struct btrfs_trans_handle *trans;
1951         int ret;
1952
1953         ret = -EPERM;
1954         if (!capable(CAP_SYS_ADMIN))
1955                 goto out;
1956
1957         ret = -EINPROGRESS;
1958         if (file->private_data)
1959                 goto out;
1960
1961         ret = mnt_want_write(file->f_path.mnt);
1962         if (ret)
1963                 goto out;
1964
1965         mutex_lock(&root->fs_info->trans_mutex);
1966         root->fs_info->open_ioctl_trans++;
1967         mutex_unlock(&root->fs_info->trans_mutex);
1968
1969         ret = -ENOMEM;
1970         trans = btrfs_start_ioctl_transaction(root, 0);
1971         if (!trans)
1972                 goto out_drop;
1973
1974         file->private_data = trans;
1975         return 0;
1976
1977 out_drop:
1978         mutex_lock(&root->fs_info->trans_mutex);
1979         root->fs_info->open_ioctl_trans--;
1980         mutex_unlock(&root->fs_info->trans_mutex);
1981         mnt_drop_write(file->f_path.mnt);
1982 out:
1983         return ret;
1984 }
1985
1986 static long btrfs_ioctl_default_subvol(struct file *file, void __user *argp)
1987 {
1988         struct inode *inode = fdentry(file)->d_inode;
1989         struct btrfs_root *root = BTRFS_I(inode)->root;
1990         struct btrfs_root *new_root;
1991         struct btrfs_dir_item *di;
1992         struct btrfs_trans_handle *trans;
1993         struct btrfs_path *path;
1994         struct btrfs_key location;
1995         struct btrfs_disk_key disk_key;
1996         struct btrfs_super_block *disk_super;
1997         u64 features;
1998         u64 objectid = 0;
1999         u64 dir_id;
2000
2001         if (!capable(CAP_SYS_ADMIN))
2002                 return -EPERM;
2003
2004         if (copy_from_user(&objectid, argp, sizeof(objectid)))
2005                 return -EFAULT;
2006
2007         if (!objectid)
2008                 objectid = root->root_key.objectid;
2009
2010         location.objectid = objectid;
2011         location.type = BTRFS_ROOT_ITEM_KEY;
2012         location.offset = (u64)-1;
2013
2014         new_root = btrfs_read_fs_root_no_name(root->fs_info, &location);
2015         if (IS_ERR(new_root))
2016                 return PTR_ERR(new_root);
2017
2018         if (btrfs_root_refs(&new_root->root_item) == 0)
2019                 return -ENOENT;
2020
2021         path = btrfs_alloc_path();
2022         if (!path)
2023                 return -ENOMEM;
2024         path->leave_spinning = 1;
2025
2026         trans = btrfs_start_transaction(root, 1);
2027         if (!trans) {
2028                 btrfs_free_path(path);
2029                 return -ENOMEM;
2030         }
2031
2032         dir_id = btrfs_super_root_dir(&root->fs_info->super_copy);
2033         di = btrfs_lookup_dir_item(trans, root->fs_info->tree_root, path,
2034                                    dir_id, "default", 7, 1);
2035         if (IS_ERR_OR_NULL(di)) {
2036                 btrfs_free_path(path);
2037                 btrfs_end_transaction(trans, root);
2038                 printk(KERN_ERR "Umm, you don't have the default dir item, "
2039                        "this isn't going to work\n");
2040                 return -ENOENT;
2041         }
2042
2043         btrfs_cpu_key_to_disk(&disk_key, &new_root->root_key);
2044         btrfs_set_dir_item_key(path->nodes[0], di, &disk_key);
2045         btrfs_mark_buffer_dirty(path->nodes[0]);
2046         btrfs_free_path(path);
2047
2048         disk_super = &root->fs_info->super_copy;
2049         features = btrfs_super_incompat_flags(disk_super);
2050         if (!(features & BTRFS_FEATURE_INCOMPAT_DEFAULT_SUBVOL)) {
2051                 features |= BTRFS_FEATURE_INCOMPAT_DEFAULT_SUBVOL;
2052                 btrfs_set_super_incompat_flags(disk_super, features);
2053         }
2054         btrfs_end_transaction(trans, root);
2055
2056         return 0;
2057 }
2058
2059 static void get_block_group_info(struct list_head *groups_list,
2060                                  struct btrfs_ioctl_space_info *space)
2061 {
2062         struct btrfs_block_group_cache *block_group;
2063
2064         space->total_bytes = 0;
2065         space->used_bytes = 0;
2066         space->flags = 0;
2067         list_for_each_entry(block_group, groups_list, list) {
2068                 space->flags = block_group->flags;
2069                 space->total_bytes += block_group->key.offset;
2070                 space->used_bytes +=
2071                         btrfs_block_group_used(&block_group->item);
2072         }
2073 }
2074
2075 long btrfs_ioctl_space_info(struct btrfs_root *root, void __user *arg)
2076 {
2077         struct btrfs_ioctl_space_args space_args;
2078         struct btrfs_ioctl_space_info space;
2079         struct btrfs_ioctl_space_info *dest;
2080         struct btrfs_ioctl_space_info *dest_orig;
2081         struct btrfs_ioctl_space_info *user_dest;
2082         struct btrfs_space_info *info;
2083         u64 types[] = {BTRFS_BLOCK_GROUP_DATA,
2084                        BTRFS_BLOCK_GROUP_SYSTEM,
2085                        BTRFS_BLOCK_GROUP_METADATA,
2086                        BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA};
2087         int num_types = 4;
2088         int alloc_size;
2089         int ret = 0;
2090         int slot_count = 0;
2091         int i, c;
2092
2093         if (copy_from_user(&space_args,
2094                            (struct btrfs_ioctl_space_args __user *)arg,
2095                            sizeof(space_args)))
2096                 return -EFAULT;
2097
2098         for (i = 0; i < num_types; i++) {
2099                 struct btrfs_space_info *tmp;
2100
2101                 info = NULL;
2102                 rcu_read_lock();
2103                 list_for_each_entry_rcu(tmp, &root->fs_info->space_info,
2104                                         list) {
2105                         if (tmp->flags == types[i]) {
2106                                 info = tmp;
2107                                 break;
2108                         }
2109                 }
2110                 rcu_read_unlock();
2111
2112                 if (!info)
2113                         continue;
2114
2115                 down_read(&info->groups_sem);
2116                 for (c = 0; c < BTRFS_NR_RAID_TYPES; c++) {
2117                         if (!list_empty(&info->block_groups[c]))
2118                                 slot_count++;
2119                 }
2120                 up_read(&info->groups_sem);
2121         }
2122
2123         /* space_slots == 0 means they are asking for a count */
2124         if (space_args.space_slots == 0) {
2125                 space_args.total_spaces = slot_count;
2126                 goto out;
2127         }
2128
2129         slot_count = min_t(int, space_args.space_slots, slot_count);
2130
2131         alloc_size = sizeof(*dest) * slot_count;
2132
2133         /* we generally have at most 6 or so space infos, one for each raid
2134          * level.  So, a whole page should be more than enough for everyone
2135          */
2136         if (alloc_size > PAGE_CACHE_SIZE)
2137                 return -ENOMEM;
2138
2139         space_args.total_spaces = 0;
2140         dest = kmalloc(alloc_size, GFP_NOFS);
2141         if (!dest)
2142                 return -ENOMEM;
2143         dest_orig = dest;
2144
2145         /* now we have a buffer to copy into */
2146         for (i = 0; i < num_types; i++) {
2147                 struct btrfs_space_info *tmp;
2148
2149                 info = NULL;
2150                 rcu_read_lock();
2151                 list_for_each_entry_rcu(tmp, &root->fs_info->space_info,
2152                                         list) {
2153                         if (tmp->flags == types[i]) {
2154                                 info = tmp;
2155                                 break;
2156                         }
2157                 }
2158                 rcu_read_unlock();
2159
2160                 if (!info)
2161                         continue;
2162                 down_read(&info->groups_sem);
2163                 for (c = 0; c < BTRFS_NR_RAID_TYPES; c++) {
2164                         if (!list_empty(&info->block_groups[c])) {
2165                                 get_block_group_info(&info->block_groups[c],
2166                                                      &space);
2167                                 memcpy(dest, &space, sizeof(space));
2168                                 dest++;
2169                                 space_args.total_spaces++;
2170                         }
2171                 }
2172                 up_read(&info->groups_sem);
2173         }
2174
2175         user_dest = (struct btrfs_ioctl_space_info *)
2176                 (arg + sizeof(struct btrfs_ioctl_space_args));
2177
2178         if (copy_to_user(user_dest, dest_orig, alloc_size))
2179                 ret = -EFAULT;
2180
2181         kfree(dest_orig);
2182 out:
2183         if (ret == 0 && copy_to_user(arg, &space_args, sizeof(space_args)))
2184                 ret = -EFAULT;
2185
2186         return ret;
2187 }
2188
2189 /*
2190  * there are many ways the trans_start and trans_end ioctls can lead
2191  * to deadlocks.  They should only be used by applications that
2192  * basically own the machine, and have a very in depth understanding
2193  * of all the possible deadlocks and enospc problems.
2194  */
2195 long btrfs_ioctl_trans_end(struct file *file)
2196 {
2197         struct inode *inode = fdentry(file)->d_inode;
2198         struct btrfs_root *root = BTRFS_I(inode)->root;
2199         struct btrfs_trans_handle *trans;
2200
2201         trans = file->private_data;
2202         if (!trans)
2203                 return -EINVAL;
2204         file->private_data = NULL;
2205
2206         btrfs_end_transaction(trans, root);
2207
2208         mutex_lock(&root->fs_info->trans_mutex);
2209         root->fs_info->open_ioctl_trans--;
2210         mutex_unlock(&root->fs_info->trans_mutex);
2211
2212         mnt_drop_write(file->f_path.mnt);
2213         return 0;
2214 }
2215
2216 static noinline long btrfs_ioctl_start_sync(struct file *file, void __user *argp)
2217 {
2218         struct btrfs_root *root = BTRFS_I(file->f_dentry->d_inode)->root;
2219         struct btrfs_trans_handle *trans;
2220         u64 transid;
2221
2222         trans = btrfs_start_transaction(root, 0);
2223         transid = trans->transid;
2224         btrfs_commit_transaction_async(trans, root, 0);
2225
2226         if (argp)
2227                 if (copy_to_user(argp, &transid, sizeof(transid)))
2228                         return -EFAULT;
2229         return 0;
2230 }
2231
2232 static noinline long btrfs_ioctl_wait_sync(struct file *file, void __user *argp)
2233 {
2234         struct btrfs_root *root = BTRFS_I(file->f_dentry->d_inode)->root;
2235         u64 transid;
2236
2237         if (argp) {
2238                 if (copy_from_user(&transid, argp, sizeof(transid)))
2239                         return -EFAULT;
2240         } else {
2241                 transid = 0;  /* current trans */
2242         }
2243         return btrfs_wait_for_commit(root, transid);
2244 }
2245
2246 long btrfs_ioctl(struct file *file, unsigned int
2247                 cmd, unsigned long arg)
2248 {
2249         struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root;
2250         void __user *argp = (void __user *)arg;
2251
2252         switch (cmd) {
2253         case FS_IOC_GETFLAGS:
2254                 return btrfs_ioctl_getflags(file, argp);
2255         case FS_IOC_SETFLAGS:
2256                 return btrfs_ioctl_setflags(file, argp);
2257         case FS_IOC_GETVERSION:
2258                 return btrfs_ioctl_getversion(file, argp);
2259         case BTRFS_IOC_SNAP_CREATE:
2260                 return btrfs_ioctl_snap_create(file, argp, 0, 0);
2261         case BTRFS_IOC_SNAP_CREATE_V2:
2262                 return btrfs_ioctl_snap_create(file, argp, 0, 1);
2263         case BTRFS_IOC_SUBVOL_CREATE:
2264                 return btrfs_ioctl_snap_create(file, argp, 1, 0);
2265         case BTRFS_IOC_SNAP_DESTROY:
2266                 return btrfs_ioctl_snap_destroy(file, argp);
2267         case BTRFS_IOC_DEFAULT_SUBVOL:
2268                 return btrfs_ioctl_default_subvol(file, argp);
2269         case BTRFS_IOC_DEFRAG:
2270                 return btrfs_ioctl_defrag(file, NULL);
2271         case BTRFS_IOC_DEFRAG_RANGE:
2272                 return btrfs_ioctl_defrag(file, argp);
2273         case BTRFS_IOC_RESIZE:
2274                 return btrfs_ioctl_resize(root, argp);
2275         case BTRFS_IOC_ADD_DEV:
2276                 return btrfs_ioctl_add_dev(root, argp);
2277         case BTRFS_IOC_RM_DEV:
2278                 return btrfs_ioctl_rm_dev(root, argp);
2279         case BTRFS_IOC_BALANCE:
2280                 return btrfs_balance(root->fs_info->dev_root);
2281         case BTRFS_IOC_CLONE:
2282                 return btrfs_ioctl_clone(file, arg, 0, 0, 0);
2283         case BTRFS_IOC_CLONE_RANGE:
2284                 return btrfs_ioctl_clone_range(file, argp);
2285         case BTRFS_IOC_TRANS_START:
2286                 return btrfs_ioctl_trans_start(file);
2287         case BTRFS_IOC_TRANS_END:
2288                 return btrfs_ioctl_trans_end(file);
2289         case BTRFS_IOC_TREE_SEARCH:
2290                 return btrfs_ioctl_tree_search(file, argp);
2291         case BTRFS_IOC_INO_LOOKUP:
2292                 return btrfs_ioctl_ino_lookup(file, argp);
2293         case BTRFS_IOC_SPACE_INFO:
2294                 return btrfs_ioctl_space_info(root, argp);
2295         case BTRFS_IOC_SYNC:
2296                 btrfs_sync_fs(file->f_dentry->d_sb, 1);
2297                 return 0;
2298         case BTRFS_IOC_START_SYNC:
2299                 return btrfs_ioctl_start_sync(file, argp);
2300         case BTRFS_IOC_WAIT_SYNC:
2301                 return btrfs_ioctl_wait_sync(file, argp);
2302         }
2303
2304         return -ENOTTY;
2305 }