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 <linux/blkdev.h>
  44 #include "compat.h"
  45 #include "ctree.h"
  46 #include "disk-io.h"
  47 #include "transaction.h"
  48 #include "btrfs_inode.h"
  49 #include "ioctl.h"
  50 #include "print-tree.h"
  51 #include "volumes.h"
  52 #include "locking.h"
  53 #include "inode-map.h"
  54
  55 /* Mask out flags that are inappropriate for the given type of inode. */
  56 static inline __u32 btrfs_mask_flags(umode_t mode, __u32 flags)
  57 {
  58         if (S_ISDIR(mode))
  59                 return flags;
  60         else if (S_ISREG(mode))
  61                 return flags & ~FS_DIRSYNC_FL;
  62         else
  63                 return flags & (FS_NODUMP_FL | FS_NOATIME_FL);
  64 }
  65
  66 /*
  67  * Export inode flags to the format expected by the FS_IOC_GETFLAGS ioctl.
  68  */
  69 static unsigned int btrfs_flags_to_ioctl(unsigned int flags)
  70 {
  71         unsigned int iflags = 0;
  72
  73         if (flags & BTRFS_INODE_SYNC)
  74                 iflags |= FS_SYNC_FL;
  75         if (flags & BTRFS_INODE_IMMUTABLE)
  76                 iflags |= FS_IMMUTABLE_FL;
  77         if (flags & BTRFS_INODE_APPEND)
  78                 iflags |= FS_APPEND_FL;
  79         if (flags & BTRFS_INODE_NODUMP)
  80                 iflags |= FS_NODUMP_FL;
  81         if (flags & BTRFS_INODE_NOATIME)
  82                 iflags |= FS_NOATIME_FL;
  83         if (flags & BTRFS_INODE_DIRSYNC)
  84                 iflags |= FS_DIRSYNC_FL;
  85         if (flags & BTRFS_INODE_NODATACOW)
  86                 iflags |= FS_NOCOW_FL;
  87
  88         if ((flags & BTRFS_INODE_COMPRESS) && !(flags & BTRFS_INODE_NOCOMPRESS))
  89                 iflags |= FS_COMPR_FL;
  90         else if (flags & BTRFS_INODE_NOCOMPRESS)
  91                 iflags |= FS_NOCOMP_FL;
  92
  93         return iflags;
  94 }
  95
  96 /*
  97  * Update inode->i_flags based on the btrfs internal flags.
  98  */
  99 void btrfs_update_iflags(struct inode *inode)
 100 {
 101         struct btrfs_inode *ip = BTRFS_I(inode);
 102
 103         inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
 104
 105         if (ip->flags & BTRFS_INODE_SYNC)
 106                 inode->i_flags |= S_SYNC;
 107         if (ip->flags & BTRFS_INODE_IMMUTABLE)
 108                 inode->i_flags |= S_IMMUTABLE;
 109         if (ip->flags & BTRFS_INODE_APPEND)
 110                 inode->i_flags |= S_APPEND;
 111         if (ip->flags & BTRFS_INODE_NOATIME)
 112                 inode->i_flags |= S_NOATIME;
 113         if (ip->flags & BTRFS_INODE_DIRSYNC)
 114                 inode->i_flags |= S_DIRSYNC;
 115 }
 116
 117 /*
 118  * Inherit flags from the parent inode.
 119  *
 120  * Unlike extN we don't have any flags we don't want to inherit currently.
 121  */
 122 void btrfs_inherit_iflags(struct inode *inode, struct inode *dir)
 123 {
 124         unsigned int flags;
 125
 126         if (!dir)
 127                 return;
 128
 129         flags = BTRFS_I(dir)->flags;
 130
 131         if (S_ISREG(inode->i_mode))
 132                 flags &= ~BTRFS_INODE_DIRSYNC;
 133         else if (!S_ISDIR(inode->i_mode))
 134                 flags &= (BTRFS_INODE_NODUMP | BTRFS_INODE_NOATIME);
 135
 136         BTRFS_I(inode)->flags = flags;
 137         btrfs_update_iflags(inode);
 138 }
 139
 140 static int btrfs_ioctl_getflags(struct file *file, void __user *arg)
 141 {
 142         struct btrfs_inode *ip = BTRFS_I(file->f_path.dentry->d_inode);
 143         unsigned int flags = btrfs_flags_to_ioctl(ip->flags);
 144
 145         if (copy_to_user(arg, &flags, sizeof(flags)))
 146                 return -EFAULT;
 147         return 0;
 148 }
 149
 150 static int check_flags(unsigned int flags)
 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                       FS_NOCOMP_FL | FS_COMPR_FL |
 156                       FS_NOCOW_FL))
 157                 return -EOPNOTSUPP;
 158
 159         if ((flags & FS_NOCOMP_FL) && (flags & FS_COMPR_FL))
 160                 return -EINVAL;
 161
 162         return 0;
 163 }
 164
 165 static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
 166 {
 167         struct inode *inode = file->f_path.dentry->d_inode;
 168         struct btrfs_inode *ip = BTRFS_I(inode);
 169         struct btrfs_root *root = ip->root;
 170         struct btrfs_trans_handle *trans;
 171         unsigned int flags, oldflags;
 172         int ret;
 173
 174         if (btrfs_root_readonly(root))
 175                 return -EROFS;
 176
 177         if (copy_from_user(&flags, arg, sizeof(flags)))
 178                 return -EFAULT;
 179
 180         ret = check_flags(flags);
 181         if (ret)
 182                 return ret;
 183
 184         if (!inode_owner_or_capable(inode))
 185                 return -EACCES;
 186
 187         mutex_lock(&inode->i_mutex);
 188
 189         flags = btrfs_mask_flags(inode->i_mode, flags);
 190         oldflags = btrfs_flags_to_ioctl(ip->flags);
 191         if ((flags ^ oldflags) & (FS_APPEND_FL | FS_IMMUTABLE_FL)) {
 192                 if (!capable(CAP_LINUX_IMMUTABLE)) {
 193                         ret = -EPERM;
 194                         goto out_unlock;
 195                 }
 196         }
 197
 198         ret = mnt_want_write(file->f_path.mnt);
 199         if (ret)
 200                 goto out_unlock;
 201
 202         if (flags & FS_SYNC_FL)
 203                 ip->flags |= BTRFS_INODE_SYNC;
 204         else
 205                 ip->flags &= ~BTRFS_INODE_SYNC;
 206         if (flags & FS_IMMUTABLE_FL)
 207                 ip->flags |= BTRFS_INODE_IMMUTABLE;
 208         else
 209                 ip->flags &= ~BTRFS_INODE_IMMUTABLE;
 210         if (flags & FS_APPEND_FL)
 211                 ip->flags |= BTRFS_INODE_APPEND;
 212         else
 213                 ip->flags &= ~BTRFS_INODE_APPEND;
 214         if (flags & FS_NODUMP_FL)
 215                 ip->flags |= BTRFS_INODE_NODUMP;
 216         else
 217                 ip->flags &= ~BTRFS_INODE_NODUMP;
 218         if (flags & FS_NOATIME_FL)
 219                 ip->flags |= BTRFS_INODE_NOATIME;
 220         else
 221                 ip->flags &= ~BTRFS_INODE_NOATIME;
 222         if (flags & FS_DIRSYNC_FL)
 223                 ip->flags |= BTRFS_INODE_DIRSYNC;
 224         else
 225                 ip->flags &= ~BTRFS_INODE_DIRSYNC;
 226         if (flags & FS_NOCOW_FL)
 227                 ip->flags |= BTRFS_INODE_NODATACOW;
 228         else
 229                 ip->flags &= ~BTRFS_INODE_NODATACOW;
 230
 231         /*
 232          * The COMPRESS flag can only be changed by users, while the NOCOMPRESS
 233          * flag may be changed automatically if compression code won't make
 234          * things smaller.
 235          */
 236         if (flags & FS_NOCOMP_FL) {
 237                 ip->flags &= ~BTRFS_INODE_COMPRESS;
 238                 ip->flags |= BTRFS_INODE_NOCOMPRESS;
 239         } else if (flags & FS_COMPR_FL) {
 240                 ip->flags |= BTRFS_INODE_COMPRESS;
 241                 ip->flags &= ~BTRFS_INODE_NOCOMPRESS;
 242         } else {
 243                 ip->flags &= ~(BTRFS_INODE_COMPRESS | BTRFS_INODE_NOCOMPRESS);
 244         }
 245
 246         trans = btrfs_join_transaction(root);
 247         BUG_ON(IS_ERR(trans));
 248
 249         ret = btrfs_update_inode(trans, root, inode);
 250         BUG_ON(ret);
 251
 252         btrfs_update_iflags(inode);
 253         inode->i_ctime = CURRENT_TIME;
 254         btrfs_end_transaction(trans, root);
 255
 256         mnt_drop_write(file->f_path.mnt);
 257
 258         ret = 0;
 259  out_unlock:
 260         mutex_unlock(&inode->i_mutex);
 261         return ret;
 262 }
 263
 264 static int btrfs_ioctl_getversion(struct file *file, int __user *arg)
 265 {
 266         struct inode *inode = file->f_path.dentry->d_inode;
 267
 268         return put_user(inode->i_generation, arg);
 269 }
 270
 271 static noinline int btrfs_ioctl_fitrim(struct file *file, void __user *arg)
 272 {
 273         struct btrfs_root *root = fdentry(file)->d_sb->s_fs_info;
 274         struct btrfs_fs_info *fs_info = root->fs_info;
 275         struct btrfs_device *device;
 276         struct request_queue *q;
 277         struct fstrim_range range;
 278         u64 minlen = ULLONG_MAX;
 279         u64 num_devices = 0;
 280         int ret;
 281
 282         if (!capable(CAP_SYS_ADMIN))
 283                 return -EPERM;
 284
 285         rcu_read_lock();
 286         list_for_each_entry_rcu(device, &fs_info->fs_devices->devices,
 287                                 dev_list) {
 288                 if (!device->bdev)
 289                         continue;
 290                 q = bdev_get_queue(device->bdev);
 291                 if (blk_queue_discard(q)) {
 292                         num_devices++;
 293                         minlen = min((u64)q->limits.discard_granularity,
 294                                      minlen);
 295                 }
 296         }
 297         rcu_read_unlock();
 298         if (!num_devices)
 299                 return -EOPNOTSUPP;
 300
 301         if (copy_from_user(&range, arg, sizeof(range)))
 302                 return -EFAULT;
 303
 304         range.minlen = max(range.minlen, minlen);
 305         ret = btrfs_trim_fs(root, &range);
 306         if (ret < 0)
 307                 return ret;
 308
 309         if (copy_to_user(arg, &range, sizeof(range)))
 310                 return -EFAULT;
 311
 312         return 0;
 313 }
 314
 315 static noinline int create_subvol(struct btrfs_root *root,
 316                                   struct dentry *dentry,
 317                                   char *name, int namelen,
 318                                   u64 *async_transid)
 319 {
 320         struct btrfs_trans_handle *trans;
 321         struct btrfs_key key;
 322         struct btrfs_root_item root_item;
 323         struct btrfs_inode_item *inode_item;
 324         struct extent_buffer *leaf;
 325         struct btrfs_root *new_root;
 326         struct dentry *parent = dget_parent(dentry);
 327         struct inode *dir;
 328         int ret;
 329         int err;
 330         u64 objectid;
 331         u64 new_dirid = BTRFS_FIRST_FREE_OBJECTID;
 332         u64 index = 0;
 333
 334         ret = btrfs_find_free_objectid(root->fs_info->tree_root, &objectid);
 335         if (ret) {
 336                 dput(parent);
 337                 return ret;
 338         }
 339
 340         dir = parent->d_inode;
 341
 342         /*
 343          * 1 - inode item
 344          * 2 - refs
 345          * 1 - root item
 346          * 2 - dir items
 347          */
 348         trans = btrfs_start_transaction(root, 6);
 349         if (IS_ERR(trans)) {
 350                 dput(parent);
 351                 return PTR_ERR(trans);
 352         }
 353
 354         leaf = btrfs_alloc_free_block(trans, root, root->leafsize,
 355                                       0, objectid, NULL, 0, 0, 0);
 356         if (IS_ERR(leaf)) {
 357                 ret = PTR_ERR(leaf);
 358                 goto fail;
 359         }
 360
 361         memset_extent_buffer(leaf, 0, 0, sizeof(struct btrfs_header));
 362         btrfs_set_header_bytenr(leaf, leaf->start);
 363         btrfs_set_header_generation(leaf, trans->transid);
 364         btrfs_set_header_backref_rev(leaf, BTRFS_MIXED_BACKREF_REV);
 365         btrfs_set_header_owner(leaf, objectid);
 366
 367         write_extent_buffer(leaf, root->fs_info->fsid,
 368                             (unsigned long)btrfs_header_fsid(leaf),
 369                             BTRFS_FSID_SIZE);
 370         write_extent_buffer(leaf, root->fs_info->chunk_tree_uuid,
 371                             (unsigned long)btrfs_header_chunk_tree_uuid(leaf),
 372                             BTRFS_UUID_SIZE);
 373         btrfs_mark_buffer_dirty(leaf);
 374
 375         inode_item = &root_item.inode;
 376         memset(inode_item, 0, sizeof(*inode_item));
 377         inode_item->generation = cpu_to_le64(1);
 378         inode_item->size = cpu_to_le64(3);
 379         inode_item->nlink = cpu_to_le32(1);
 380         inode_item->nbytes = cpu_to_le64(root->leafsize);
 381         inode_item->mode = cpu_to_le32(S_IFDIR | 0755);
 382
 383         root_item.flags = 0;
 384         root_item.byte_limit = 0;
 385         inode_item->flags = cpu_to_le64(BTRFS_INODE_ROOT_ITEM_INIT);
 386
 387         btrfs_set_root_bytenr(&root_item, leaf->start);
 388         btrfs_set_root_generation(&root_item, trans->transid);
 389         btrfs_set_root_level(&root_item, 0);
 390         btrfs_set_root_refs(&root_item, 1);
 391         btrfs_set_root_used(&root_item, leaf->len);
 392         btrfs_set_root_last_snapshot(&root_item, 0);
 393
 394         memset(&root_item.drop_progress, 0, sizeof(root_item.drop_progress));
 395         root_item.drop_level = 0;
 396
 397         btrfs_tree_unlock(leaf);
 398         free_extent_buffer(leaf);
 399         leaf = NULL;
 400
 401         btrfs_set_root_dirid(&root_item, new_dirid);
 402
 403         key.objectid = objectid;
 404         key.offset = 0;
 405         btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
 406         ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key,
 407                                 &root_item);
 408         if (ret)
 409                 goto fail;
 410
 411         key.offset = (u64)-1;
 412         new_root = btrfs_read_fs_root_no_name(root->fs_info, &key);
 413         BUG_ON(IS_ERR(new_root));
 414
 415         btrfs_record_root_in_trans(trans, new_root);
 416
 417         ret = btrfs_create_subvol_root(trans, new_root, new_dirid);
 418         /*
 419          * insert the directory item
 420          */
 421         ret = btrfs_set_inode_index(dir, &index);
 422         BUG_ON(ret);
 423
 424         ret = btrfs_insert_dir_item(trans, root,
 425                                     name, namelen, dir, &key,
 426                                     BTRFS_FT_DIR, index);
 427         if (ret)
 428                 goto fail;
 429
 430         btrfs_i_size_write(dir, dir->i_size + namelen * 2);
 431         ret = btrfs_update_inode(trans, root, dir);
 432         BUG_ON(ret);
 433
 434         ret = btrfs_add_root_ref(trans, root->fs_info->tree_root,
 435                                  objectid, root->root_key.objectid,
 436                                  btrfs_ino(dir), index, name, namelen);
 437
 438         BUG_ON(ret);
 439
 440         d_instantiate(dentry, btrfs_lookup_dentry(dir, dentry));
 441 fail:
 442         dput(parent);
 443         if (async_transid) {
 444                 *async_transid = trans->transid;
 445                 err = btrfs_commit_transaction_async(trans, root, 1);
 446         } else {
 447                 err = btrfs_commit_transaction(trans, root);
 448         }
 449         if (err && !ret)
 450                 ret = err;
 451         return ret;
 452 }
 453
 454 static int create_snapshot(struct btrfs_root *root, struct dentry *dentry,
 455                            char *name, int namelen, u64 *async_transid,
 456                            bool readonly)
 457 {
 458         struct inode *inode;
 459         struct dentry *parent;
 460         struct btrfs_pending_snapshot *pending_snapshot;
 461         struct btrfs_trans_handle *trans;
 462         int ret;
 463
 464         if (!root->ref_cows)
 465                 return -EINVAL;
 466
 467         pending_snapshot = kzalloc(sizeof(*pending_snapshot), GFP_NOFS);
 468         if (!pending_snapshot)
 469                 return -ENOMEM;
 470
 471         btrfs_init_block_rsv(&pending_snapshot->block_rsv);
 472         pending_snapshot->dentry = dentry;
 473         pending_snapshot->root = root;
 474         pending_snapshot->readonly = readonly;
 475
 476         trans = btrfs_start_transaction(root->fs_info->extent_root, 5);
 477         if (IS_ERR(trans)) {
 478                 ret = PTR_ERR(trans);
 479                 goto fail;
 480         }
 481
 482         ret = btrfs_snap_reserve_metadata(trans, pending_snapshot);
 483         BUG_ON(ret);
 484
 485         list_add(&pending_snapshot->list,
 486                  &trans->transaction->pending_snapshots);
 487         if (async_transid) {
 488                 *async_transid = trans->transid;
 489                 ret = btrfs_commit_transaction_async(trans,
 490                                      root->fs_info->extent_root, 1);
 491         } else {
 492                 ret = btrfs_commit_transaction(trans,
 493                                                root->fs_info->extent_root);
 494         }
 495         BUG_ON(ret);
 496
 497         ret = pending_snapshot->error;
 498         if (ret)
 499                 goto fail;
 500
 501         ret = btrfs_orphan_cleanup(pending_snapshot->snap);
 502         if (ret)
 503                 goto fail;
 504
 505         parent = dget_parent(dentry);
 506         inode = btrfs_lookup_dentry(parent->d_inode, dentry);
 507         dput(parent);
 508         if (IS_ERR(inode)) {
 509                 ret = PTR_ERR(inode);
 510                 goto fail;
 511         }
 512         BUG_ON(!inode);
 513         d_instantiate(dentry, inode);
 514         ret = 0;
 515 fail:
 516         kfree(pending_snapshot);
 517         return ret;
 518 }
 519
 520 /*  copy of check_sticky in fs/namei.c()
 521 * It's inline, so penalty for filesystems that don't use sticky bit is
 522 * minimal.
 523 */
 524 static inline int btrfs_check_sticky(struct inode *dir, struct inode *inode)
 525 {
 526         uid_t fsuid = current_fsuid();
 527
 528         if (!(dir->i_mode & S_ISVTX))
 529                 return 0;
 530         if (inode->i_uid == fsuid)
 531                 return 0;
 532         if (dir->i_uid == fsuid)
 533                 return 0;
 534         return !capable(CAP_FOWNER);
 535 }
 536
 537 /*  copy of may_delete in fs/namei.c()
 538  *      Check whether we can remove a link victim from directory dir, check
 539  *  whether the type of victim is right.
 540  *  1. We can't do it if dir is read-only (done in permission())
 541  *  2. We should have write and exec permissions on dir
 542  *  3. We can't remove anything from append-only dir
 543  *  4. We can't do anything with immutable dir (done in permission())
 544  *  5. If the sticky bit on dir is set we should either
 545  *      a. be owner of dir, or
 546  *      b. be owner of victim, or
 547  *      c. have CAP_FOWNER capability
 548  *  6. If the victim is append-only or immutable we can't do antyhing with
 549  *     links pointing to it.
 550  *  7. If we were asked to remove a directory and victim isn't one - ENOTDIR.
 551  *  8. If we were asked to remove a non-directory and victim isn't one - EISDIR.
 552  *  9. We can't remove a root or mountpoint.
 553  * 10. We don't allow removal of NFS sillyrenamed files; it's handled by
 554  *     nfs_async_unlink().
 555  */
 556
 557 static int btrfs_may_delete(struct inode *dir,struct dentry *victim,int isdir)
 558 {
 559         int error;
 560
 561         if (!victim->d_inode)
 562                 return -ENOENT;
 563
 564         BUG_ON(victim->d_parent->d_inode != dir);
 565         audit_inode_child(victim, dir);
 566
 567         error = inode_permission(dir, MAY_WRITE | MAY_EXEC);
 568         if (error)
 569                 return error;
 570         if (IS_APPEND(dir))
 571                 return -EPERM;
 572         if (btrfs_check_sticky(dir, victim->d_inode)||
 573                 IS_APPEND(victim->d_inode)||
 574             IS_IMMUTABLE(victim->d_inode) || IS_SWAPFILE(victim->d_inode))
 575                 return -EPERM;
 576         if (isdir) {
 577                 if (!S_ISDIR(victim->d_inode->i_mode))
 578                         return -ENOTDIR;
 579                 if (IS_ROOT(victim))
 580                         return -EBUSY;
 581         } else if (S_ISDIR(victim->d_inode->i_mode))
 582                 return -EISDIR;
 583         if (IS_DEADDIR(dir))
 584                 return -ENOENT;
 585         if (victim->d_flags & DCACHE_NFSFS_RENAMED)
 586                 return -EBUSY;
 587         return 0;
 588 }
 589
 590 /* copy of may_create in fs/namei.c() */
 591 static inline int btrfs_may_create(struct inode *dir, struct dentry *child)
 592 {
 593         if (child->d_inode)
 594                 return -EEXIST;
 595         if (IS_DEADDIR(dir))
 596                 return -ENOENT;
 597         return inode_permission(dir, MAY_WRITE | MAY_EXEC);
 598 }
 599
 600 /*
 601  * Create a new subvolume below @parent.  This is largely modeled after
 602  * sys_mkdirat and vfs_mkdir, but we only do a single component lookup
 603  * inside this filesystem so it's quite a bit simpler.
 604  */
 605 static noinline int btrfs_mksubvol(struct path *parent,
 606                                    char *name, int namelen,
 607                                    struct btrfs_root *snap_src,
 608                                    u64 *async_transid, bool readonly)
 609 {
 610         struct inode *dir  = parent->dentry->d_inode;
 611         struct dentry *dentry;
 612         int error;
 613
 614         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 615
 616         dentry = lookup_one_len(name, parent->dentry, namelen);
 617         error = PTR_ERR(dentry);
 618         if (IS_ERR(dentry))
 619                 goto out_unlock;
 620
 621         error = -EEXIST;
 622         if (dentry->d_inode)
 623                 goto out_dput;
 624
 625         error = mnt_want_write(parent->mnt);
 626         if (error)
 627                 goto out_dput;
 628
 629         error = btrfs_may_create(dir, dentry);
 630         if (error)
 631                 goto out_drop_write;
 632
 633         down_read(&BTRFS_I(dir)->root->fs_info->subvol_sem);
 634
 635         if (btrfs_root_refs(&BTRFS_I(dir)->root->root_item) == 0)
 636                 goto out_up_read;
 637
 638         if (snap_src) {
 639                 error = create_snapshot(snap_src, dentry,
 640                                         name, namelen, async_transid, readonly);
 641         } else {
 642                 error = create_subvol(BTRFS_I(dir)->root, dentry,
 643                                       name, namelen, async_transid);
 644         }
 645         if (!error)
 646                 fsnotify_mkdir(dir, dentry);
 647 out_up_read:
 648         up_read(&BTRFS_I(dir)->root->fs_info->subvol_sem);
 649 out_drop_write:
 650         mnt_drop_write(parent->mnt);
 651 out_dput:
 652         dput(dentry);
 653 out_unlock:
 654         mutex_unlock(&dir->i_mutex);
 655         return error;
 656 }
 657
 658 /*
 659  * When we're defragging a range, we don't want to kick it off again
 660  * if it is really just waiting for delalloc to send it down.
 661  * If we find a nice big extent or delalloc range for the bytes in the
 662  * file you want to defrag, we return 0 to let you know to skip this
 663  * part of the file
 664  */
 665 static int check_defrag_in_cache(struct inode *inode, u64 offset, int thresh)
 666 {
 667         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
 668         struct extent_map *em = NULL;
 669         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 670         u64 end;
 671
 672         read_lock(&em_tree->lock);
 673         em = lookup_extent_mapping(em_tree, offset, PAGE_CACHE_SIZE);
 674         read_unlock(&em_tree->lock);
 675
 676         if (em) {
 677                 end = extent_map_end(em);
 678                 free_extent_map(em);
 679                 if (end - offset > thresh)
 680                         return 0;
 681         }
 682         /* if we already have a nice delalloc here, just stop */
 683         thresh /= 2;
 684         end = count_range_bits(io_tree, &offset, offset + thresh,
 685                                thresh, EXTENT_DELALLOC, 1);
 686         if (end >= thresh)
 687                 return 0;
 688         return 1;
 689 }
 690
 691 /*
 692  * helper function to walk through a file and find extents
 693  * newer than a specific transid, and smaller than thresh.
 694  *
 695  * This is used by the defragging code to find new and small
 696  * extents
 697  */
 698 static int find_new_extents(struct btrfs_root *root,
 699                             struct inode *inode, u64 newer_than,
 700                             u64 *off, int thresh)
 701 {
 702         struct btrfs_path *path;
 703         struct btrfs_key min_key;
 704         struct btrfs_key max_key;
 705         struct extent_buffer *leaf;
 706         struct btrfs_file_extent_item *extent;
 707         int type;
 708         int ret;
 709         u64 ino = btrfs_ino(inode);
 710
 711         path = btrfs_alloc_path();
 712         if (!path)
 713                 return -ENOMEM;
 714
 715         min_key.objectid = ino;
 716         min_key.type = BTRFS_EXTENT_DATA_KEY;
 717         min_key.offset = *off;
 718
 719         max_key.objectid = ino;
 720         max_key.type = (u8)-1;
 721         max_key.offset = (u64)-1;
 722
 723         path->keep_locks = 1;
 724
 725         while(1) {
 726                 ret = btrfs_search_forward(root, &min_key, &max_key,
 727                                            path, 0, newer_than);
 728                 if (ret != 0)
 729                         goto none;
 730                 if (min_key.objectid != ino)
 731                         goto none;
 732                 if (min_key.type != BTRFS_EXTENT_DATA_KEY)
 733                         goto none;
 734
 735                 leaf = path->nodes[0];
 736                 extent = btrfs_item_ptr(leaf, path->slots[0],
 737                                         struct btrfs_file_extent_item);
 738
 739                 type = btrfs_file_extent_type(leaf, extent);
 740                 if (type == BTRFS_FILE_EXTENT_REG &&
 741                     btrfs_file_extent_num_bytes(leaf, extent) < thresh &&
 742                     check_defrag_in_cache(inode, min_key.offset, thresh)) {
 743                         *off = min_key.offset;
 744                         btrfs_free_path(path);
 745                         return 0;
 746                 }
 747
 748                 if (min_key.offset == (u64)-1)
 749                         goto none;
 750
 751                 min_key.offset++;
 752                 btrfs_release_path(path);
 753         }
 754 none:
 755         btrfs_free_path(path);
 756         return -ENOENT;
 757 }
 758
 759 static int should_defrag_range(struct inode *inode, u64 start, u64 len,
 760                                int thresh, u64 *last_len, u64 *skip,
 761                                u64 *defrag_end)
 762 {
 763         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
 764         struct extent_map *em = NULL;
 765         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 766         int ret = 1;
 767
 768         /*
 769          * make sure that once we start defragging and extent, we keep on
 770          * defragging it
 771          */
 772         if (start < *defrag_end)
 773                 return 1;
 774
 775         *skip = 0;
 776
 777         /*
 778          * hopefully we have this extent in the tree already, try without
 779          * the full extent lock
 780          */
 781         read_lock(&em_tree->lock);
 782         em = lookup_extent_mapping(em_tree, start, len);
 783         read_unlock(&em_tree->lock);
 784
 785         if (!em) {
 786                 /* get the big lock and read metadata off disk */
 787                 lock_extent(io_tree, start, start + len - 1, GFP_NOFS);
 788                 em = btrfs_get_extent(inode, NULL, 0, start, len, 0);
 789                 unlock_extent(io_tree, start, start + len - 1, GFP_NOFS);
 790
 791                 if (IS_ERR(em))
 792                         return 0;
 793         }
 794
 795         /* this will cover holes, and inline extents */
 796         if (em->block_start >= EXTENT_MAP_LAST_BYTE)
 797                 ret = 0;
 798
 799         /*
 800          * we hit a real extent, if it is big don't bother defragging it again
 801          */
 802         if ((*last_len == 0 || *last_len >= thresh) && em->len >= thresh)
 803                 ret = 0;
 804
 805         /*
 806          * last_len ends up being a counter of how many bytes we've defragged.
 807          * every time we choose not to defrag an extent, we reset *last_len
 808          * so that the next tiny extent will force a defrag.
 809          *
 810          * The end result of this is that tiny extents before a single big
 811          * extent will force at least part of that big extent to be defragged.
 812          */
 813         if (ret) {
 814                 *last_len += len;
 815                 *defrag_end = extent_map_end(em);
 816         } else {
 817                 *last_len = 0;
 818                 *skip = extent_map_end(em);
 819                 *defrag_end = 0;
 820         }
 821
 822         free_extent_map(em);
 823         return ret;
 824 }
 825
 826 /*
 827  * it doesn't do much good to defrag one or two pages
 828  * at a time.  This pulls in a nice chunk of pages
 829  * to COW and defrag.
 830  *
 831  * It also makes sure the delalloc code has enough
 832  * dirty data to avoid making new small extents as part
 833  * of the defrag
 834  *
 835  * It's a good idea to start RA on this range
 836  * before calling this.
 837  */
 838 static int cluster_pages_for_defrag(struct inode *inode,
 839                                     struct page **pages,
 840                                     unsigned long start_index,
 841                                     int num_pages)
 842 {
 843         unsigned long file_end;
 844         u64 isize = i_size_read(inode);
 845         u64 page_start;
 846         u64 page_end;
 847         int ret;
 848         int i;
 849         int i_done;
 850         struct btrfs_ordered_extent *ordered;
 851         struct extent_state *cached_state = NULL;
 852
 853         if (isize == 0)
 854                 return 0;
 855         file_end = (isize - 1) >> PAGE_CACHE_SHIFT;
 856
 857         ret = btrfs_delalloc_reserve_space(inode,
 858                                            num_pages << PAGE_CACHE_SHIFT);
 859         if (ret)
 860                 return ret;
 861 again:
 862         ret = 0;
 863         i_done = 0;
 864
 865         /* step one, lock all the pages */
 866         for (i = 0; i < num_pages; i++) {
 867                 struct page *page;
 868                 page = grab_cache_page(inode->i_mapping,
 869                                             start_index + i);
 870                 if (!page)
 871                         break;
 872
 873                 if (!PageUptodate(page)) {
 874                         btrfs_readpage(NULL, page);
 875                         lock_page(page);
 876                         if (!PageUptodate(page)) {
 877                                 unlock_page(page);
 878                                 page_cache_release(page);
 879                                 ret = -EIO;
 880                                 break;
 881                         }
 882                 }
 883                 isize = i_size_read(inode);
 884                 file_end = (isize - 1) >> PAGE_CACHE_SHIFT;
 885                 if (!isize || page->index > file_end ||
 886                     page->mapping != inode->i_mapping) {
 887                         /* whoops, we blew past eof, skip this page */
 888                         unlock_page(page);
 889                         page_cache_release(page);
 890                         break;
 891                 }
 892                 pages[i] = page;
 893                 i_done++;
 894         }
 895         if (!i_done || ret)
 896                 goto out;
 897
 898         if (!(inode->i_sb->s_flags & MS_ACTIVE))
 899                 goto out;
 900
 901         /*
 902          * so now we have a nice long stream of locked
 903          * and up to date pages, lets wait on them
 904          */
 905         for (i = 0; i < i_done; i++)
 906                 wait_on_page_writeback(pages[i]);
 907
 908         page_start = page_offset(pages[0]);
 909         page_end = page_offset(pages[i_done - 1]) + PAGE_CACHE_SIZE;
 910
 911         lock_extent_bits(&BTRFS_I(inode)->io_tree,
 912                          page_start, page_end - 1, 0, &cached_state,
 913                          GFP_NOFS);
 914         ordered = btrfs_lookup_first_ordered_extent(inode, page_end - 1);
 915         if (ordered &&
 916             ordered->file_offset + ordered->len > page_start &&
 917             ordered->file_offset < page_end) {
 918                 btrfs_put_ordered_extent(ordered);
 919                 unlock_extent_cached(&BTRFS_I(inode)->io_tree,
 920                                      page_start, page_end - 1,
 921                                      &cached_state, GFP_NOFS);
 922                 for (i = 0; i < i_done; i++) {
 923                         unlock_page(pages[i]);
 924                         page_cache_release(pages[i]);
 925                 }
 926                 btrfs_wait_ordered_range(inode, page_start,
 927                                          page_end - page_start);
 928                 goto again;
 929         }
 930         if (ordered)
 931                 btrfs_put_ordered_extent(ordered);
 932
 933         clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start,
 934                           page_end - 1, EXTENT_DIRTY | EXTENT_DELALLOC |
 935                           EXTENT_DO_ACCOUNTING, 0, 0, &cached_state,
 936                           GFP_NOFS);
 937
 938         if (i_done != num_pages) {
 939                 atomic_inc(&BTRFS_I(inode)->outstanding_extents);
 940                 btrfs_delalloc_release_space(inode,
 941                                      (num_pages - i_done) << PAGE_CACHE_SHIFT);
 942         }
 943
 944
 945         btrfs_set_extent_delalloc(inode, page_start, page_end - 1,
 946                                   &cached_state);
 947
 948         unlock_extent_cached(&BTRFS_I(inode)->io_tree,
 949                              page_start, page_end - 1, &cached_state,
 950                              GFP_NOFS);
 951
 952         for (i = 0; i < i_done; i++) {
 953                 clear_page_dirty_for_io(pages[i]);
 954                 ClearPageChecked(pages[i]);
 955                 set_page_extent_mapped(pages[i]);
 956                 set_page_dirty(pages[i]);
 957                 unlock_page(pages[i]);
 958                 page_cache_release(pages[i]);
 959         }
 960         return i_done;
 961 out:
 962         for (i = 0; i < i_done; i++) {
 963                 unlock_page(pages[i]);
 964                 page_cache_release(pages[i]);
 965         }
 966         btrfs_delalloc_release_space(inode, num_pages << PAGE_CACHE_SHIFT);
 967         return ret;
 968
 969 }
 970
 971 int btrfs_defrag_file(struct inode *inode, struct file *file,
 972                       struct btrfs_ioctl_defrag_range_args *range,
 973                       u64 newer_than, unsigned long max_to_defrag)
 974 {
 975         struct btrfs_root *root = BTRFS_I(inode)->root;
 976         struct btrfs_super_block *disk_super;
 977         struct file_ra_state *ra = NULL;
 978         unsigned long last_index;
 979         u64 features;
 980         u64 last_len = 0;
 981         u64 skip = 0;
 982         u64 defrag_end = 0;
 983         u64 newer_off = range->start;
 984         int newer_left = 0;
 985         unsigned long i;
 986         int ret;
 987         int defrag_count = 0;
 988         int compress_type = BTRFS_COMPRESS_ZLIB;
 989         int extent_thresh = range->extent_thresh;
 990         int newer_cluster = (256 * 1024) >> PAGE_CACHE_SHIFT;
 991         u64 new_align = ~((u64)128 * 1024 - 1);
 992         struct page **pages = NULL;
 993
 994         if (extent_thresh == 0)
 995                 extent_thresh = 256 * 1024;
 996
 997         if (range->flags & BTRFS_DEFRAG_RANGE_COMPRESS) {
 998                 if (range->compress_type > BTRFS_COMPRESS_TYPES)
 999                         return -EINVAL;
1000                 if (range->compress_type)
1001                         compress_type = range->compress_type;
1002         }
1003
1004         if (inode->i_size == 0)
1005                 return 0;
1006
1007         /*
1008          * if we were not given a file, allocate a readahead
1009          * context
1010          */
1011         if (!file) {
1012                 ra = kzalloc(sizeof(*ra), GFP_NOFS);
1013                 if (!ra)
1014                         return -ENOMEM;
1015                 file_ra_state_init(ra, inode->i_mapping);
1016         } else {
1017                 ra = &file->f_ra;
1018         }
1019
1020         pages = kmalloc(sizeof(struct page *) * newer_cluster,
1021                         GFP_NOFS);
1022         if (!pages) {
1023                 ret = -ENOMEM;
1024                 goto out_ra;
1025         }
1026
1027         /* find the last page to defrag */
1028         if (range->start + range->len > range->start) {
1029                 last_index = min_t(u64, inode->i_size - 1,
1030                          range->start + range->len - 1) >> PAGE_CACHE_SHIFT;
1031         } else {
1032                 last_index = (inode->i_size - 1) >> PAGE_CACHE_SHIFT;
1033         }
1034
1035         if (newer_than) {
1036                 ret = find_new_extents(root, inode, newer_than,
1037                                        &newer_off, 64 * 1024);
1038                 if (!ret) {
1039                         range->start = newer_off;
1040                         /*
1041                          * we always align our defrag to help keep
1042                          * the extents in the file evenly spaced
1043                          */
1044                         i = (newer_off & new_align) >> PAGE_CACHE_SHIFT;
1045                         newer_left = newer_cluster;
1046                 } else
1047                         goto out_ra;
1048         } else {
1049                 i = range->start >> PAGE_CACHE_SHIFT;
1050         }
1051         if (!max_to_defrag)
1052                 max_to_defrag = last_index - 1;
1053
1054         while (i <= last_index && defrag_count < max_to_defrag) {
1055                 /*
1056                  * make sure we stop running if someone unmounts
1057                  * the FS
1058                  */
1059                 if (!(inode->i_sb->s_flags & MS_ACTIVE))
1060                         break;
1061
1062                 if (!newer_than &&
1063                     !should_defrag_range(inode, (u64)i << PAGE_CACHE_SHIFT,
1064                                         PAGE_CACHE_SIZE,
1065                                         extent_thresh,
1066                                         &last_len, &skip,
1067                                         &defrag_end)) {
1068                         unsigned long next;
1069                         /*
1070                          * the should_defrag function tells us how much to skip
1071                          * bump our counter by the suggested amount
1072                          */
1073                         next = (skip + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
1074                         i = max(i + 1, next);
1075                         continue;
1076                 }
1077                 if (range->flags & BTRFS_DEFRAG_RANGE_COMPRESS)
1078                         BTRFS_I(inode)->force_compress = compress_type;
1079
1080                 btrfs_force_ra(inode->i_mapping, ra, file, i, newer_cluster);
1081
1082                 ret = cluster_pages_for_defrag(inode, pages, i, newer_cluster);
1083                 if (ret < 0)
1084                         goto out_ra;
1085
1086                 defrag_count += ret;
1087                 balance_dirty_pages_ratelimited_nr(inode->i_mapping, ret);
1088                 i += ret;
1089
1090                 if (newer_than) {
1091                         if (newer_off == (u64)-1)
1092                                 break;
1093
1094                         newer_off = max(newer_off + 1,
1095                                         (u64)i << PAGE_CACHE_SHIFT);
1096
1097                         ret = find_new_extents(root, inode,
1098                                                newer_than, &newer_off,
1099                                                64 * 1024);
1100                         if (!ret) {
1101                                 range->start = newer_off;
1102                                 i = (newer_off & new_align) >> PAGE_CACHE_SHIFT;
1103                                 newer_left = newer_cluster;
1104                         } else {
1105                                 break;
1106                         }
1107                 } else {
1108                         i++;
1109                 }
1110         }
1111
1112         if ((range->flags & BTRFS_DEFRAG_RANGE_START_IO))
1113                 filemap_flush(inode->i_mapping);
1114
1115         if ((range->flags & BTRFS_DEFRAG_RANGE_COMPRESS)) {
1116                 /* the filemap_flush will queue IO into the worker threads, but
1117                  * we have to make sure the IO is actually started and that
1118                  * ordered extents get created before we return
1119                  */
1120                 atomic_inc(&root->fs_info->async_submit_draining);
1121                 while (atomic_read(&root->fs_info->nr_async_submits) ||
1122                       atomic_read(&root->fs_info->async_delalloc_pages)) {
1123                         wait_event(root->fs_info->async_submit_wait,
1124                            (atomic_read(&root->fs_info->nr_async_submits) == 0 &&
1125                             atomic_read(&root->fs_info->async_delalloc_pages) == 0));
1126                 }
1127                 atomic_dec(&root->fs_info->async_submit_draining);
1128
1129                 mutex_lock(&inode->i_mutex);
1130                 BTRFS_I(inode)->force_compress = BTRFS_COMPRESS_NONE;
1131                 mutex_unlock(&inode->i_mutex);
1132         }
1133
1134         disk_super = &root->fs_info->super_copy;
1135         features = btrfs_super_incompat_flags(disk_super);
1136         if (range->compress_type == BTRFS_COMPRESS_LZO) {
1137                 features |= BTRFS_FEATURE_INCOMPAT_COMPRESS_LZO;
1138                 btrfs_set_super_incompat_flags(disk_super, features);
1139         }
1140
1141         if (!file)
1142                 kfree(ra);
1143         return defrag_count;
1144
1145 out_ra:
1146         if (!file)
1147                 kfree(ra);
1148         kfree(pages);
1149         return ret;
1150 }
1151
1152 static noinline int btrfs_ioctl_resize(struct btrfs_root *root,
1153                                         void __user *arg)
1154 {
1155         u64 new_size;
1156         u64 old_size;
1157         u64 devid = 1;
1158         struct btrfs_ioctl_vol_args *vol_args;
1159         struct btrfs_trans_handle *trans;
1160         struct btrfs_device *device = NULL;
1161         char *sizestr;
1162         char *devstr = NULL;
1163         int ret = 0;
1164         int mod = 0;
1165
1166         if (root->fs_info->sb->s_flags & MS_RDONLY)
1167                 return -EROFS;
1168
1169         if (!capable(CAP_SYS_ADMIN))
1170                 return -EPERM;
1171
1172         vol_args = memdup_user(arg, sizeof(*vol_args));
1173         if (IS_ERR(vol_args))
1174                 return PTR_ERR(vol_args);
1175
1176         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
1177
1178         mutex_lock(&root->fs_info->volume_mutex);
1179         sizestr = vol_args->name;
1180         devstr = strchr(sizestr, ':');
1181         if (devstr) {
1182                 char *end;
1183                 sizestr = devstr + 1;
1184                 *devstr = '\0';
1185                 devstr = vol_args->name;
1186                 devid = simple_strtoull(devstr, &end, 10);
1187                 printk(KERN_INFO "resizing devid %llu\n",
1188                        (unsigned long long)devid);
1189         }
1190         device = btrfs_find_device(root, devid, NULL, NULL);
1191         if (!device) {
1192                 printk(KERN_INFO "resizer unable to find device %llu\n",
1193                        (unsigned long long)devid);
1194                 ret = -EINVAL;
1195                 goto out_unlock;
1196         }
1197         if (!strcmp(sizestr, "max"))
1198                 new_size = device->bdev->bd_inode->i_size;
1199         else {
1200                 if (sizestr[0] == '-') {
1201                         mod = -1;
1202                         sizestr++;
1203                 } else if (sizestr[0] == '+') {
1204                         mod = 1;
1205                         sizestr++;
1206                 }
1207                 new_size = memparse(sizestr, NULL);
1208                 if (new_size == 0) {
1209                         ret = -EINVAL;
1210                         goto out_unlock;
1211                 }
1212         }
1213
1214         old_size = device->total_bytes;
1215
1216         if (mod < 0) {
1217                 if (new_size > old_size) {
1218                         ret = -EINVAL;
1219                         goto out_unlock;
1220                 }
1221                 new_size = old_size - new_size;
1222         } else if (mod > 0) {
1223                 new_size = old_size + new_size;
1224         }
1225
1226         if (new_size < 256 * 1024 * 1024) {
1227                 ret = -EINVAL;
1228                 goto out_unlock;
1229         }
1230         if (new_size > device->bdev->bd_inode->i_size) {
1231                 ret = -EFBIG;
1232                 goto out_unlock;
1233         }
1234
1235         do_div(new_size, root->sectorsize);
1236         new_size *= root->sectorsize;
1237
1238         printk(KERN_INFO "new size for %s is %llu\n",
1239                 device->name, (unsigned long long)new_size);
1240
1241         if (new_size > old_size) {
1242                 trans = btrfs_start_transaction(root, 0);
1243                 if (IS_ERR(trans)) {
1244                         ret = PTR_ERR(trans);
1245                         goto out_unlock;
1246                 }
1247                 ret = btrfs_grow_device(trans, device, new_size);
1248                 btrfs_commit_transaction(trans, root);
1249         } else {
1250                 ret = btrfs_shrink_device(device, new_size);
1251         }
1252
1253 out_unlock:
1254         mutex_unlock(&root->fs_info->volume_mutex);
1255         kfree(vol_args);
1256         return ret;
1257 }
1258
1259 static noinline int btrfs_ioctl_snap_create_transid(struct file *file,
1260                                                     char *name,
1261                                                     unsigned long fd,
1262                                                     int subvol,
1263                                                     u64 *transid,
1264                                                     bool readonly)
1265 {
1266         struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root;
1267         struct file *src_file;
1268         int namelen;
1269         int ret = 0;
1270
1271         if (root->fs_info->sb->s_flags & MS_RDONLY)
1272                 return -EROFS;
1273
1274         namelen = strlen(name);
1275         if (strchr(name, '/')) {
1276                 ret = -EINVAL;
1277                 goto out;
1278         }
1279
1280         if (subvol) {
1281                 ret = btrfs_mksubvol(&file->f_path, name, namelen,
1282                                      NULL, transid, readonly);
1283         } else {
1284                 struct inode *src_inode;
1285                 src_file = fget(fd);
1286                 if (!src_file) {
1287                         ret = -EINVAL;
1288                         goto out;
1289                 }
1290
1291                 src_inode = src_file->f_path.dentry->d_inode;
1292                 if (src_inode->i_sb != file->f_path.dentry->d_inode->i_sb) {
1293                         printk(KERN_INFO "btrfs: Snapshot src from "
1294                                "another FS\n");
1295                         ret = -EINVAL;
1296                         fput(src_file);
1297                         goto out;
1298                 }
1299                 ret = btrfs_mksubvol(&file->f_path, name, namelen,
1300                                      BTRFS_I(src_inode)->root,
1301                                      transid, readonly);
1302                 fput(src_file);
1303         }
1304 out:
1305         return ret;
1306 }
1307
1308 static noinline int btrfs_ioctl_snap_create(struct file *file,
1309                                             void __user *arg, int subvol)
1310 {
1311         struct btrfs_ioctl_vol_args *vol_args;
1312         int ret;
1313
1314         vol_args = memdup_user(arg, sizeof(*vol_args));
1315         if (IS_ERR(vol_args))
1316                 return PTR_ERR(vol_args);
1317         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
1318
1319         ret = btrfs_ioctl_snap_create_transid(file, vol_args->name,
1320                                               vol_args->fd, subvol,
1321                                               NULL, false);
1322
1323         kfree(vol_args);
1324         return ret;
1325 }
1326
1327 static noinline int btrfs_ioctl_snap_create_v2(struct file *file,
1328                                                void __user *arg, int subvol)
1329 {
1330         struct btrfs_ioctl_vol_args_v2 *vol_args;
1331         int ret;
1332         u64 transid = 0;
1333         u64 *ptr = NULL;
1334         bool readonly = false;
1335
1336         vol_args = memdup_user(arg, sizeof(*vol_args));
1337         if (IS_ERR(vol_args))
1338                 return PTR_ERR(vol_args);
1339         vol_args->name[BTRFS_SUBVOL_NAME_MAX] = '\0';
1340
1341         if (vol_args->flags &
1342             ~(BTRFS_SUBVOL_CREATE_ASYNC | BTRFS_SUBVOL_RDONLY)) {
1343                 ret = -EOPNOTSUPP;
1344                 goto out;
1345         }
1346
1347         if (vol_args->flags & BTRFS_SUBVOL_CREATE_ASYNC)
1348                 ptr = &transid;
1349         if (vol_args->flags & BTRFS_SUBVOL_RDONLY)
1350                 readonly = true;
1351
1352         ret = btrfs_ioctl_snap_create_transid(file, vol_args->name,
1353                                               vol_args->fd, subvol,
1354                                               ptr, readonly);
1355
1356         if (ret == 0 && ptr &&
1357             copy_to_user(arg +
1358                          offsetof(struct btrfs_ioctl_vol_args_v2,
1359                                   transid), ptr, sizeof(*ptr)))
1360                 ret = -EFAULT;
1361 out:
1362         kfree(vol_args);
1363         return ret;
1364 }
1365
1366 static noinline int btrfs_ioctl_subvol_getflags(struct file *file,
1367                                                 void __user *arg)
1368 {
1369         struct inode *inode = fdentry(file)->d_inode;
1370         struct btrfs_root *root = BTRFS_I(inode)->root;
1371         int ret = 0;
1372         u64 flags = 0;
1373
1374         if (btrfs_ino(inode) != BTRFS_FIRST_FREE_OBJECTID)
1375                 return -EINVAL;
1376
1377         down_read(&root->fs_info->subvol_sem);
1378         if (btrfs_root_readonly(root))
1379                 flags |= BTRFS_SUBVOL_RDONLY;
1380         up_read(&root->fs_info->subvol_sem);
1381
1382         if (copy_to_user(arg, &flags, sizeof(flags)))
1383                 ret = -EFAULT;
1384
1385         return ret;
1386 }
1387
1388 static noinline int btrfs_ioctl_subvol_setflags(struct file *file,
1389                                               void __user *arg)
1390 {
1391         struct inode *inode = fdentry(file)->d_inode;
1392         struct btrfs_root *root = BTRFS_I(inode)->root;
1393         struct btrfs_trans_handle *trans;
1394         u64 root_flags;
1395         u64 flags;
1396         int ret = 0;
1397
1398         if (root->fs_info->sb->s_flags & MS_RDONLY)
1399                 return -EROFS;
1400
1401         if (btrfs_ino(inode) != BTRFS_FIRST_FREE_OBJECTID)
1402                 return -EINVAL;
1403
1404         if (copy_from_user(&flags, arg, sizeof(flags)))
1405                 return -EFAULT;
1406
1407         if (flags & BTRFS_SUBVOL_CREATE_ASYNC)
1408                 return -EINVAL;
1409
1410         if (flags & ~BTRFS_SUBVOL_RDONLY)
1411                 return -EOPNOTSUPP;
1412
1413         if (!inode_owner_or_capable(inode))
1414                 return -EACCES;
1415
1416         down_write(&root->fs_info->subvol_sem);
1417
1418         /* nothing to do */
1419         if (!!(flags & BTRFS_SUBVOL_RDONLY) == btrfs_root_readonly(root))
1420                 goto out;
1421
1422         root_flags = btrfs_root_flags(&root->root_item);
1423         if (flags & BTRFS_SUBVOL_RDONLY)
1424                 btrfs_set_root_flags(&root->root_item,
1425                                      root_flags | BTRFS_ROOT_SUBVOL_RDONLY);
1426         else
1427                 btrfs_set_root_flags(&root->root_item,
1428                                      root_flags & ~BTRFS_ROOT_SUBVOL_RDONLY);
1429
1430         trans = btrfs_start_transaction(root, 1);
1431         if (IS_ERR(trans)) {
1432                 ret = PTR_ERR(trans);
1433                 goto out_reset;
1434         }
1435
1436         ret = btrfs_update_root(trans, root->fs_info->tree_root,
1437                                 &root->root_key, &root->root_item);
1438
1439         btrfs_commit_transaction(trans, root);
1440 out_reset:
1441         if (ret)
1442                 btrfs_set_root_flags(&root->root_item, root_flags);
1443 out:
1444         up_write(&root->fs_info->subvol_sem);
1445         return ret;
1446 }
1447
1448 /*
1449  * helper to check if the subvolume references other subvolumes
1450  */
1451 static noinline int may_destroy_subvol(struct btrfs_root *root)
1452 {
1453         struct btrfs_path *path;
1454         struct btrfs_key key;
1455         int ret;
1456
1457         path = btrfs_alloc_path();
1458         if (!path)
1459                 return -ENOMEM;
1460
1461         key.objectid = root->root_key.objectid;
1462         key.type = BTRFS_ROOT_REF_KEY;
1463         key.offset = (u64)-1;
1464
1465         ret = btrfs_search_slot(NULL, root->fs_info->tree_root,
1466                                 &key, path, 0, 0);
1467         if (ret < 0)
1468                 goto out;
1469         BUG_ON(ret == 0);
1470
1471         ret = 0;
1472         if (path->slots[0] > 0) {
1473                 path->slots[0]--;
1474                 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1475                 if (key.objectid == root->root_key.objectid &&
1476                     key.type == BTRFS_ROOT_REF_KEY)
1477                         ret = -ENOTEMPTY;
1478         }
1479 out:
1480         btrfs_free_path(path);
1481         return ret;
1482 }
1483
1484 static noinline int key_in_sk(struct btrfs_key *key,
1485                               struct btrfs_ioctl_search_key *sk)
1486 {
1487         struct btrfs_key test;
1488         int ret;
1489
1490         test.objectid = sk->min_objectid;
1491         test.type = sk->min_type;
1492         test.offset = sk->min_offset;
1493
1494         ret = btrfs_comp_cpu_keys(key, &test);
1495         if (ret < 0)
1496                 return 0;
1497
1498         test.objectid = sk->max_objectid;
1499         test.type = sk->max_type;
1500         test.offset = sk->max_offset;
1501
1502         ret = btrfs_comp_cpu_keys(key, &test);
1503         if (ret > 0)
1504                 return 0;
1505         return 1;
1506 }
1507
1508 static noinline int copy_to_sk(struct btrfs_root *root,
1509                                struct btrfs_path *path,
1510                                struct btrfs_key *key,
1511                                struct btrfs_ioctl_search_key *sk,
1512                                char *buf,
1513                                unsigned long *sk_offset,
1514                                int *num_found)
1515 {
1516         u64 found_transid;
1517         struct extent_buffer *leaf;
1518         struct btrfs_ioctl_search_header sh;
1519         unsigned long item_off;
1520         unsigned long item_len;
1521         int nritems;
1522         int i;
1523         int slot;
1524         int ret = 0;
1525
1526         leaf = path->nodes[0];
1527         slot = path->slots[0];
1528         nritems = btrfs_header_nritems(leaf);
1529
1530         if (btrfs_header_generation(leaf) > sk->max_transid) {
1531                 i = nritems;
1532                 goto advance_key;
1533         }
1534         found_transid = btrfs_header_generation(leaf);
1535
1536         for (i = slot; i < nritems; i++) {
1537                 item_off = btrfs_item_ptr_offset(leaf, i);
1538                 item_len = btrfs_item_size_nr(leaf, i);
1539
1540                 if (item_len > BTRFS_SEARCH_ARGS_BUFSIZE)
1541                         item_len = 0;
1542
1543                 if (sizeof(sh) + item_len + *sk_offset >
1544                     BTRFS_SEARCH_ARGS_BUFSIZE) {
1545                         ret = 1;
1546                         goto overflow;
1547                 }
1548
1549                 btrfs_item_key_to_cpu(leaf, key, i);
1550                 if (!key_in_sk(key, sk))
1551                         continue;
1552
1553                 sh.objectid = key->objectid;
1554                 sh.offset = key->offset;
1555                 sh.type = key->type;
1556                 sh.len = item_len;
1557                 sh.transid = found_transid;
1558
1559                 /* copy search result header */
1560                 memcpy(buf + *sk_offset, &sh, sizeof(sh));
1561                 *sk_offset += sizeof(sh);
1562
1563                 if (item_len) {
1564                         char *p = buf + *sk_offset;
1565                         /* copy the item */
1566                         read_extent_buffer(leaf, p,
1567                                            item_off, item_len);
1568                         *sk_offset += item_len;
1569                 }
1570                 (*num_found)++;
1571
1572                 if (*num_found >= sk->nr_items)
1573                         break;
1574         }
1575 advance_key:
1576         ret = 0;
1577         if (key->offset < (u64)-1 && key->offset < sk->max_offset)
1578                 key->offset++;
1579         else if (key->type < (u8)-1 && key->type < sk->max_type) {
1580                 key->offset = 0;
1581                 key->type++;
1582         } else if (key->objectid < (u64)-1 && key->objectid < sk->max_objectid) {
1583                 key->offset = 0;
1584                 key->type = 0;
1585                 key->objectid++;
1586         } else
1587                 ret = 1;
1588 overflow:
1589         return ret;
1590 }
1591
1592 static noinline int search_ioctl(struct inode *inode,
1593                                  struct btrfs_ioctl_search_args *args)
1594 {
1595         struct btrfs_root *root;
1596         struct btrfs_key key;
1597         struct btrfs_key max_key;
1598         struct btrfs_path *path;
1599         struct btrfs_ioctl_search_key *sk = &args->key;
1600         struct btrfs_fs_info *info = BTRFS_I(inode)->root->fs_info;
1601         int ret;
1602         int num_found = 0;
1603         unsigned long sk_offset = 0;
1604
1605         path = btrfs_alloc_path();
1606         if (!path)
1607                 return -ENOMEM;
1608
1609         if (sk->tree_id == 0) {
1610                 /* search the root of the inode that was passed */
1611                 root = BTRFS_I(inode)->root;
1612         } else {
1613                 key.objectid = sk->tree_id;
1614                 key.type = BTRFS_ROOT_ITEM_KEY;
1615                 key.offset = (u64)-1;
1616                 root = btrfs_read_fs_root_no_name(info, &key);
1617                 if (IS_ERR(root)) {
1618                         printk(KERN_ERR "could not find root %llu\n",
1619                                sk->tree_id);
1620                         btrfs_free_path(path);
1621                         return -ENOENT;
1622                 }
1623         }
1624
1625         key.objectid = sk->min_objectid;
1626         key.type = sk->min_type;
1627         key.offset = sk->min_offset;
1628
1629         max_key.objectid = sk->max_objectid;
1630         max_key.type = sk->max_type;
1631         max_key.offset = sk->max_offset;
1632
1633         path->keep_locks = 1;
1634
1635         while(1) {
1636                 ret = btrfs_search_forward(root, &key, &max_key, path, 0,
1637                                            sk->min_transid);
1638                 if (ret != 0) {
1639                         if (ret > 0)
1640                                 ret = 0;
1641                         goto err;
1642                 }
1643                 ret = copy_to_sk(root, path, &key, sk, args->buf,
1644                                  &sk_offset, &num_found);
1645                 btrfs_release_path(path);
1646                 if (ret || num_found >= sk->nr_items)
1647                         break;
1648
1649         }
1650         ret = 0;
1651 err:
1652         sk->nr_items = num_found;
1653         btrfs_free_path(path);
1654         return ret;
1655 }
1656
1657 static noinline int btrfs_ioctl_tree_search(struct file *file,
1658                                            void __user *argp)
1659 {
1660          struct btrfs_ioctl_search_args *args;
1661          struct inode *inode;
1662          int ret;
1663
1664         if (!capable(CAP_SYS_ADMIN))
1665                 return -EPERM;
1666
1667         args = memdup_user(argp, sizeof(*args));
1668         if (IS_ERR(args))
1669                 return PTR_ERR(args);
1670
1671         inode = fdentry(file)->d_inode;
1672         ret = search_ioctl(inode, args);
1673         if (ret == 0 && copy_to_user(argp, args, sizeof(*args)))
1674                 ret = -EFAULT;
1675         kfree(args);
1676         return ret;
1677 }
1678
1679 /*
1680  * Search INODE_REFs to identify path name of 'dirid' directory
1681  * in a 'tree_id' tree. and sets path name to 'name'.
1682  */
1683 static noinline int btrfs_search_path_in_tree(struct btrfs_fs_info *info,
1684                                 u64 tree_id, u64 dirid, char *name)
1685 {
1686         struct btrfs_root *root;
1687         struct btrfs_key key;
1688         char *ptr;
1689         int ret = -1;
1690         int slot;
1691         int len;
1692         int total_len = 0;
1693         struct btrfs_inode_ref *iref;
1694         struct extent_buffer *l;
1695         struct btrfs_path *path;
1696
1697         if (dirid == BTRFS_FIRST_FREE_OBJECTID) {
1698                 name[0]='\0';
1699                 return 0;
1700         }
1701
1702         path = btrfs_alloc_path();
1703         if (!path)
1704                 return -ENOMEM;
1705
1706         ptr = &name[BTRFS_INO_LOOKUP_PATH_MAX];
1707
1708         key.objectid = tree_id;
1709         key.type = BTRFS_ROOT_ITEM_KEY;
1710         key.offset = (u64)-1;
1711         root = btrfs_read_fs_root_no_name(info, &key);
1712         if (IS_ERR(root)) {
1713                 printk(KERN_ERR "could not find root %llu\n", tree_id);
1714                 ret = -ENOENT;
1715                 goto out;
1716         }
1717
1718         key.objectid = dirid;
1719         key.type = BTRFS_INODE_REF_KEY;
1720         key.offset = (u64)-1;
1721
1722         while(1) {
1723                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1724                 if (ret < 0)
1725                         goto out;
1726
1727                 l = path->nodes[0];
1728                 slot = path->slots[0];
1729                 if (ret > 0 && slot > 0)
1730                         slot--;
1731                 btrfs_item_key_to_cpu(l, &key, slot);
1732
1733                 if (ret > 0 && (key.objectid != dirid ||
1734                                 key.type != BTRFS_INODE_REF_KEY)) {
1735                         ret = -ENOENT;
1736                         goto out;
1737                 }
1738
1739                 iref = btrfs_item_ptr(l, slot, struct btrfs_inode_ref);
1740                 len = btrfs_inode_ref_name_len(l, iref);
1741                 ptr -= len + 1;
1742                 total_len += len + 1;
1743                 if (ptr < name)
1744                         goto out;
1745
1746                 *(ptr + len) = '/';
1747                 read_extent_buffer(l, ptr,(unsigned long)(iref + 1), len);
1748
1749                 if (key.offset == BTRFS_FIRST_FREE_OBJECTID)
1750                         break;
1751
1752                 btrfs_release_path(path);
1753                 key.objectid = key.offset;
1754                 key.offset = (u64)-1;
1755                 dirid = key.objectid;
1756
1757         }
1758         if (ptr < name)
1759                 goto out;
1760         memcpy(name, ptr, total_len);
1761         name[total_len]='\0';
1762         ret = 0;
1763 out:
1764         btrfs_free_path(path);
1765         return ret;
1766 }
1767
1768 static noinline int btrfs_ioctl_ino_lookup(struct file *file,
1769                                            void __user *argp)
1770 {
1771          struct btrfs_ioctl_ino_lookup_args *args;
1772          struct inode *inode;
1773          int ret;
1774
1775         if (!capable(CAP_SYS_ADMIN))
1776                 return -EPERM;
1777
1778         args = memdup_user(argp, sizeof(*args));
1779         if (IS_ERR(args))
1780                 return PTR_ERR(args);
1781
1782         inode = fdentry(file)->d_inode;
1783
1784         if (args->treeid == 0)
1785                 args->treeid = BTRFS_I(inode)->root->root_key.objectid;
1786
1787         ret = btrfs_search_path_in_tree(BTRFS_I(inode)->root->fs_info,
1788                                         args->treeid, args->objectid,
1789                                         args->name);
1790
1791         if (ret == 0 && copy_to_user(argp, args, sizeof(*args)))
1792                 ret = -EFAULT;
1793
1794         kfree(args);
1795         return ret;
1796 }
1797
1798 static noinline int btrfs_ioctl_snap_destroy(struct file *file,
1799                                              void __user *arg)
1800 {
1801         struct dentry *parent = fdentry(file);
1802         struct dentry *dentry;
1803         struct inode *dir = parent->d_inode;
1804         struct inode *inode;
1805         struct btrfs_root *root = BTRFS_I(dir)->root;
1806         struct btrfs_root *dest = NULL;
1807         struct btrfs_ioctl_vol_args *vol_args;
1808         struct btrfs_trans_handle *trans;
1809         int namelen;
1810         int ret;
1811         int err = 0;
1812
1813         vol_args = memdup_user(arg, sizeof(*vol_args));
1814         if (IS_ERR(vol_args))
1815                 return PTR_ERR(vol_args);
1816
1817         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
1818         namelen = strlen(vol_args->name);
1819         if (strchr(vol_args->name, '/') ||
1820             strncmp(vol_args->name, "..", namelen) == 0) {
1821                 err = -EINVAL;
1822                 goto out;
1823         }
1824
1825         err = mnt_want_write(file->f_path.mnt);
1826         if (err)
1827                 goto out;
1828
1829         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
1830         dentry = lookup_one_len(vol_args->name, parent, namelen);
1831         if (IS_ERR(dentry)) {
1832                 err = PTR_ERR(dentry);
1833                 goto out_unlock_dir;
1834         }
1835
1836         if (!dentry->d_inode) {
1837                 err = -ENOENT;
1838                 goto out_dput;
1839         }
1840
1841         inode = dentry->d_inode;
1842         dest = BTRFS_I(inode)->root;
1843         if (!capable(CAP_SYS_ADMIN)){
1844                 /*
1845                  * Regular user.  Only allow this with a special mount
1846                  * option, when the user has write+exec access to the
1847                  * subvol root, and when rmdir(2) would have been
1848                  * allowed.
1849                  *
1850                  * Note that this is _not_ check that the subvol is
1851                  * empty or doesn't contain data that we wouldn't
1852                  * otherwise be able to delete.
1853                  *
1854                  * Users who want to delete empty subvols should try
1855                  * rmdir(2).
1856                  */
1857                 err = -EPERM;
1858                 if (!btrfs_test_opt(root, USER_SUBVOL_RM_ALLOWED))
1859                         goto out_dput;
1860
1861                 /*
1862                  * Do not allow deletion if the parent dir is the same
1863                  * as the dir to be deleted.  That means the ioctl
1864                  * must be called on the dentry referencing the root
1865                  * of the subvol, not a random directory contained
1866                  * within it.
1867                  */
1868                 err = -EINVAL;
1869                 if (root == dest)
1870                         goto out_dput;
1871
1872                 err = inode_permission(inode, MAY_WRITE | MAY_EXEC);
1873                 if (err)
1874                         goto out_dput;
1875
1876                 /* check if subvolume may be deleted by a non-root user */
1877                 err = btrfs_may_delete(dir, dentry, 1);
1878                 if (err)
1879                         goto out_dput;
1880         }
1881
1882         if (btrfs_ino(inode) != BTRFS_FIRST_FREE_OBJECTID) {
1883                 err = -EINVAL;
1884                 goto out_dput;
1885         }
1886
1887         mutex_lock(&inode->i_mutex);
1888         err = d_invalidate(dentry);
1889         if (err)
1890                 goto out_unlock;
1891
1892         down_write(&root->fs_info->subvol_sem);
1893
1894         err = may_destroy_subvol(dest);
1895         if (err)
1896                 goto out_up_write;
1897
1898         trans = btrfs_start_transaction(root, 0);
1899         if (IS_ERR(trans)) {
1900                 err = PTR_ERR(trans);
1901                 goto out_up_write;
1902         }
1903         trans->block_rsv = &root->fs_info->global_block_rsv;
1904
1905         ret = btrfs_unlink_subvol(trans, root, dir,
1906                                 dest->root_key.objectid,
1907                                 dentry->d_name.name,
1908                                 dentry->d_name.len);
1909         BUG_ON(ret);
1910
1911         btrfs_record_root_in_trans(trans, dest);
1912
1913         memset(&dest->root_item.drop_progress, 0,
1914                 sizeof(dest->root_item.drop_progress));
1915         dest->root_item.drop_level = 0;
1916         btrfs_set_root_refs(&dest->root_item, 0);
1917
1918         if (!xchg(&dest->orphan_item_inserted, 1)) {
1919                 ret = btrfs_insert_orphan_item(trans,
1920                                         root->fs_info->tree_root,
1921                                         dest->root_key.objectid);
1922                 BUG_ON(ret);
1923         }
1924
1925         ret = btrfs_end_transaction(trans, root);
1926         BUG_ON(ret);
1927         inode->i_flags |= S_DEAD;
1928 out_up_write:
1929         up_write(&root->fs_info->subvol_sem);
1930 out_unlock:
1931         mutex_unlock(&inode->i_mutex);
1932         if (!err) {
1933                 shrink_dcache_sb(root->fs_info->sb);
1934                 btrfs_invalidate_inodes(dest);
1935                 d_delete(dentry);
1936         }
1937 out_dput:
1938         dput(dentry);
1939 out_unlock_dir:
1940         mutex_unlock(&dir->i_mutex);
1941         mnt_drop_write(file->f_path.mnt);
1942 out:
1943         kfree(vol_args);
1944         return err;
1945 }
1946
1947 static int btrfs_ioctl_defrag(struct file *file, void __user *argp)
1948 {
1949         struct inode *inode = fdentry(file)->d_inode;
1950         struct btrfs_root *root = BTRFS_I(inode)->root;
1951         struct btrfs_ioctl_defrag_range_args *range;
1952         int ret;
1953
1954         if (btrfs_root_readonly(root))
1955                 return -EROFS;
1956
1957         ret = mnt_want_write(file->f_path.mnt);
1958         if (ret)
1959                 return ret;
1960
1961         switch (inode->i_mode & S_IFMT) {
1962         case S_IFDIR:
1963                 if (!capable(CAP_SYS_ADMIN)) {
1964                         ret = -EPERM;
1965                         goto out;
1966                 }
1967                 ret = btrfs_defrag_root(root, 0);
1968                 if (ret)
1969                         goto out;
1970                 ret = btrfs_defrag_root(root->fs_info->extent_root, 0);
1971                 break;
1972         case S_IFREG:
1973                 if (!(file->f_mode & FMODE_WRITE)) {
1974                         ret = -EINVAL;
1975                         goto out;
1976                 }
1977
1978                 range = kzalloc(sizeof(*range), GFP_KERNEL);
1979                 if (!range) {
1980                         ret = -ENOMEM;
1981                         goto out;
1982                 }
1983
1984                 if (argp) {
1985                         if (copy_from_user(range, argp,
1986                                            sizeof(*range))) {
1987                                 ret = -EFAULT;
1988                                 kfree(range);
1989                                 goto out;
1990                         }
1991                         /* compression requires us to start the IO */
1992                         if ((range->flags & BTRFS_DEFRAG_RANGE_COMPRESS)) {
1993                                 range->flags |= BTRFS_DEFRAG_RANGE_START_IO;
1994                                 range->extent_thresh = (u32)-1;
1995                         }
1996                 } else {
1997                         /* the rest are all set to zero by kzalloc */
1998                         range->len = (u64)-1;
1999                 }
2000                 ret = btrfs_defrag_file(fdentry(file)->d_inode, file,
2001                                         range, 0, 0);
2002                 if (ret > 0)
2003                         ret = 0;
2004                 kfree(range);
2005                 break;
2006         default:
2007                 ret = -EINVAL;
2008         }
2009 out:
2010         mnt_drop_write(file->f_path.mnt);
2011         return ret;
2012 }
2013
2014 static long btrfs_ioctl_add_dev(struct btrfs_root *root, void __user *arg)
2015 {
2016         struct btrfs_ioctl_vol_args *vol_args;
2017         int ret;
2018
2019         if (!capable(CAP_SYS_ADMIN))
2020                 return -EPERM;
2021
2022         vol_args = memdup_user(arg, sizeof(*vol_args));
2023         if (IS_ERR(vol_args))
2024                 return PTR_ERR(vol_args);
2025
2026         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
2027         ret = btrfs_init_new_device(root, vol_args->name);
2028
2029         kfree(vol_args);
2030         return ret;
2031 }
2032
2033 static long btrfs_ioctl_rm_dev(struct btrfs_root *root, void __user *arg)
2034 {
2035         struct btrfs_ioctl_vol_args *vol_args;
2036         int ret;
2037
2038         if (!capable(CAP_SYS_ADMIN))
2039                 return -EPERM;
2040
2041         if (root->fs_info->sb->s_flags & MS_RDONLY)
2042                 return -EROFS;
2043
2044         vol_args = memdup_user(arg, sizeof(*vol_args));
2045         if (IS_ERR(vol_args))
2046                 return PTR_ERR(vol_args);
2047
2048         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
2049         ret = btrfs_rm_device(root, vol_args->name);
2050
2051         kfree(vol_args);
2052         return ret;
2053 }
2054
2055 static long btrfs_ioctl_fs_info(struct btrfs_root *root, void __user *arg)
2056 {
2057         struct btrfs_ioctl_fs_info_args fi_args;
2058         struct btrfs_device *device;
2059         struct btrfs_device *next;
2060         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
2061
2062         if (!capable(CAP_SYS_ADMIN))
2063                 return -EPERM;
2064
2065         fi_args.num_devices = fs_devices->num_devices;
2066         fi_args.max_id = 0;
2067         memcpy(&fi_args.fsid, root->fs_info->fsid, sizeof(fi_args.fsid));
2068
2069         mutex_lock(&fs_devices->device_list_mutex);
2070         list_for_each_entry_safe(device, next, &fs_devices->devices, dev_list) {
2071                 if (device->devid > fi_args.max_id)
2072                         fi_args.max_id = device->devid;
2073         }
2074         mutex_unlock(&fs_devices->device_list_mutex);
2075
2076         if (copy_to_user(arg, &fi_args, sizeof(fi_args)))
2077                 return -EFAULT;
2078
2079         return 0;
2080 }
2081
2082 static long btrfs_ioctl_dev_info(struct btrfs_root *root, void __user *arg)
2083 {
2084         struct btrfs_ioctl_dev_info_args *di_args;
2085         struct btrfs_device *dev;
2086         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
2087         int ret = 0;
2088         char *s_uuid = NULL;
2089         char empty_uuid[BTRFS_UUID_SIZE] = {0};
2090
2091         if (!capable(CAP_SYS_ADMIN))
2092                 return -EPERM;
2093
2094         di_args = memdup_user(arg, sizeof(*di_args));
2095         if (IS_ERR(di_args))
2096                 return PTR_ERR(di_args);
2097
2098         if (memcmp(empty_uuid, di_args->uuid, BTRFS_UUID_SIZE) != 0)
2099                 s_uuid = di_args->uuid;
2100
2101         mutex_lock(&fs_devices->device_list_mutex);
2102         dev = btrfs_find_device(root, di_args->devid, s_uuid, NULL);
2103         mutex_unlock(&fs_devices->device_list_mutex);
2104
2105         if (!dev) {
2106                 ret = -ENODEV;
2107                 goto out;
2108         }
2109
2110         di_args->devid = dev->devid;
2111         di_args->bytes_used = dev->bytes_used;
2112         di_args->total_bytes = dev->total_bytes;
2113         memcpy(di_args->uuid, dev->uuid, sizeof(di_args->uuid));
2114         strncpy(di_args->path, dev->name, sizeof(di_args->path));
2115
2116 out:
2117         if (ret == 0 && copy_to_user(arg, di_args, sizeof(*di_args)))
2118                 ret = -EFAULT;
2119
2120         kfree(di_args);
2121         return ret;
2122 }
2123
2124 static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd,
2125                                        u64 off, u64 olen, u64 destoff)
2126 {
2127         struct inode *inode = fdentry(file)->d_inode;
2128         struct btrfs_root *root = BTRFS_I(inode)->root;
2129         struct file *src_file;
2130         struct inode *src;
2131         struct btrfs_trans_handle *trans;
2132         struct btrfs_path *path;
2133         struct extent_buffer *leaf;
2134         char *buf;
2135         struct btrfs_key key;
2136         u32 nritems;
2137         int slot;
2138         int ret;
2139         u64 len = olen;
2140         u64 bs = root->fs_info->sb->s_blocksize;
2141         u64 hint_byte;
2142
2143         /*
2144          * TODO:
2145          * - split compressed inline extents.  annoying: we need to
2146          *   decompress into destination's address_space (the file offset
2147          *   may change, so source mapping won't do), then recompress (or
2148          *   otherwise reinsert) a subrange.
2149          * - allow ranges within the same file to be cloned (provided
2150          *   they don't overlap)?
2151          */
2152
2153         /* the destination must be opened for writing */
2154         if (!(file->f_mode & FMODE_WRITE) || (file->f_flags & O_APPEND))
2155                 return -EINVAL;
2156
2157         if (btrfs_root_readonly(root))
2158                 return -EROFS;
2159
2160         ret = mnt_want_write(file->f_path.mnt);
2161         if (ret)
2162                 return ret;
2163
2164         src_file = fget(srcfd);
2165         if (!src_file) {
2166                 ret = -EBADF;
2167                 goto out_drop_write;
2168         }
2169
2170         src = src_file->f_dentry->d_inode;
2171
2172         ret = -EINVAL;
2173         if (src == inode)
2174                 goto out_fput;
2175
2176         /* the src must be open for reading */
2177         if (!(src_file->f_mode & FMODE_READ))
2178                 goto out_fput;
2179
2180         ret = -EISDIR;
2181         if (S_ISDIR(src->i_mode) || S_ISDIR(inode->i_mode))
2182                 goto out_fput;
2183
2184         ret = -EXDEV;
2185         if (src->i_sb != inode->i_sb || BTRFS_I(src)->root != root)
2186                 goto out_fput;
2187
2188         ret = -ENOMEM;
2189         buf = vmalloc(btrfs_level_size(root, 0));
2190         if (!buf)
2191                 goto out_fput;
2192
2193         path = btrfs_alloc_path();
2194         if (!path) {
2195                 vfree(buf);
2196                 goto out_fput;
2197         }
2198         path->reada = 2;
2199
2200         if (inode < src) {
2201                 mutex_lock_nested(&inode->i_mutex, I_MUTEX_PARENT);
2202                 mutex_lock_nested(&src->i_mutex, I_MUTEX_CHILD);
2203         } else {
2204                 mutex_lock_nested(&src->i_mutex, I_MUTEX_PARENT);
2205                 mutex_lock_nested(&inode->i_mutex, I_MUTEX_CHILD);
2206         }
2207
2208         /* determine range to clone */
2209         ret = -EINVAL;
2210         if (off + len > src->i_size || off + len < off)
2211                 goto out_unlock;
2212         if (len == 0)
2213                 olen = len = src->i_size - off;
2214         /* if we extend to eof, continue to block boundary */
2215         if (off + len == src->i_size)
2216                 len = ALIGN(src->i_size, bs) - off;
2217
2218         /* verify the end result is block aligned */
2219         if (!IS_ALIGNED(off, bs) || !IS_ALIGNED(off + len, bs) ||
2220             !IS_ALIGNED(destoff, bs))
2221                 goto out_unlock;
2222
2223         /* do any pending delalloc/csum calc on src, one way or
2224            another, and lock file content */
2225         while (1) {
2226                 struct btrfs_ordered_extent *ordered;
2227                 lock_extent(&BTRFS_I(src)->io_tree, off, off+len, GFP_NOFS);
2228                 ordered = btrfs_lookup_first_ordered_extent(src, off+len);
2229                 if (!ordered &&
2230                     !test_range_bit(&BTRFS_I(src)->io_tree, off, off+len,
2231                                    EXTENT_DELALLOC, 0, NULL))
2232                         break;
2233                 unlock_extent(&BTRFS_I(src)->io_tree, off, off+len, GFP_NOFS);
2234                 if (ordered)
2235                         btrfs_put_ordered_extent(ordered);
2236                 btrfs_wait_ordered_range(src, off, len);
2237         }
2238
2239         /* clone data */
2240         key.objectid = btrfs_ino(src);
2241         key.type = BTRFS_EXTENT_DATA_KEY;
2242         key.offset = 0;
2243
2244         while (1) {
2245                 /*
2246                  * note the key will change type as we walk through the
2247                  * tree.
2248                  */
2249                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2250                 if (ret < 0)
2251                         goto out;
2252
2253                 nritems = btrfs_header_nritems(path->nodes[0]);
2254                 if (path->slots[0] >= nritems) {
2255                         ret = btrfs_next_leaf(root, path);
2256                         if (ret < 0)
2257                                 goto out;
2258                         if (ret > 0)
2259                                 break;
2260                         nritems = btrfs_header_nritems(path->nodes[0]);
2261                 }
2262                 leaf = path->nodes[0];
2263                 slot = path->slots[0];
2264
2265                 btrfs_item_key_to_cpu(leaf, &key, slot);
2266                 if (btrfs_key_type(&key) > BTRFS_EXTENT_DATA_KEY ||
2267                     key.objectid != btrfs_ino(src))
2268                         break;
2269
2270                 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) {
2271                         struct btrfs_file_extent_item *extent;
2272                         int type;
2273                         u32 size;
2274                         struct btrfs_key new_key;
2275                         u64 disko = 0, diskl = 0;
2276                         u64 datao = 0, datal = 0;
2277                         u8 comp;
2278                         u64 endoff;
2279
2280                         size = btrfs_item_size_nr(leaf, slot);
2281                         read_extent_buffer(leaf, buf,
2282                                            btrfs_item_ptr_offset(leaf, slot),
2283                                            size);
2284
2285                         extent = btrfs_item_ptr(leaf, slot,
2286                                                 struct btrfs_file_extent_item);
2287                         comp = btrfs_file_extent_compression(leaf, extent);
2288                         type = btrfs_file_extent_type(leaf, extent);
2289                         if (type == BTRFS_FILE_EXTENT_REG ||
2290                             type == BTRFS_FILE_EXTENT_PREALLOC) {
2291                                 disko = btrfs_file_extent_disk_bytenr(leaf,
2292                                                                       extent);
2293                                 diskl = btrfs_file_extent_disk_num_bytes(leaf,
2294                                                                  extent);
2295                                 datao = btrfs_file_extent_offset(leaf, extent);
2296                                 datal = btrfs_file_extent_num_bytes(leaf,
2297                                                                     extent);
2298                         } else if (type == BTRFS_FILE_EXTENT_INLINE) {
2299                                 /* take upper bound, may be compressed */
2300                                 datal = btrfs_file_extent_ram_bytes(leaf,
2301                                                                     extent);
2302                         }
2303                         btrfs_release_path(path);
2304
2305                         if (key.offset + datal <= off ||
2306                             key.offset >= off+len)
2307                                 goto next;
2308
2309                         memcpy(&new_key, &key, sizeof(new_key));
2310                         new_key.objectid = btrfs_ino(inode);
2311                         if (off <= key.offset)
2312                                 new_key.offset = key.offset + destoff - off;
2313                         else
2314                                 new_key.offset = destoff;
2315
2316                         trans = btrfs_start_transaction(root, 1);
2317                         if (IS_ERR(trans)) {
2318                                 ret = PTR_ERR(trans);
2319                                 goto out;
2320                         }
2321
2322                         if (type == BTRFS_FILE_EXTENT_REG ||
2323                             type == BTRFS_FILE_EXTENT_PREALLOC) {
2324                                 if (off > key.offset) {
2325                                         datao += off - key.offset;
2326                                         datal -= off - key.offset;
2327                                 }
2328
2329                                 if (key.offset + datal > off + len)
2330                                         datal = off + len - key.offset;
2331
2332                                 ret = btrfs_drop_extents(trans, inode,
2333                                                          new_key.offset,
2334                                                          new_key.offset + datal,
2335                                                          &hint_byte, 1);
2336                                 BUG_ON(ret);
2337
2338                                 ret = btrfs_insert_empty_item(trans, root, path,
2339                                                               &new_key, size);
2340                                 BUG_ON(ret);
2341
2342                                 leaf = path->nodes[0];
2343                                 slot = path->slots[0];
2344                                 write_extent_buffer(leaf, buf,
2345                                             btrfs_item_ptr_offset(leaf, slot),
2346                                             size);
2347
2348                                 extent = btrfs_item_ptr(leaf, slot,
2349                                                 struct btrfs_file_extent_item);
2350
2351                                 /* disko == 0 means it's a hole */
2352                                 if (!disko)
2353                                         datao = 0;
2354
2355                                 btrfs_set_file_extent_offset(leaf, extent,
2356                                                              datao);
2357                                 btrfs_set_file_extent_num_bytes(leaf, extent,
2358                                                                 datal);
2359                                 if (disko) {
2360                                         inode_add_bytes(inode, datal);
2361                                         ret = btrfs_inc_extent_ref(trans, root,
2362                                                         disko, diskl, 0,
2363                                                         root->root_key.objectid,
2364                                                         btrfs_ino(inode),
2365                                                         new_key.offset - datao);
2366                                         BUG_ON(ret);
2367                                 }
2368                         } else if (type == BTRFS_FILE_EXTENT_INLINE) {
2369                                 u64 skip = 0;
2370                                 u64 trim = 0;
2371                                 if (off > key.offset) {
2372                                         skip = off - key.offset;
2373                                         new_key.offset += skip;
2374                                 }
2375
2376                                 if (key.offset + datal > off+len)
2377                                         trim = key.offset + datal - (off+len);
2378
2379                                 if (comp && (skip || trim)) {
2380                                         ret = -EINVAL;
2381                                         btrfs_end_transaction(trans, root);
2382                                         goto out;
2383                                 }
2384                                 size -= skip + trim;
2385                                 datal -= skip + trim;
2386
2387                                 ret = btrfs_drop_extents(trans, inode,
2388                                                          new_key.offset,
2389                                                          new_key.offset + datal,
2390                                                          &hint_byte, 1);
2391                                 BUG_ON(ret);
2392
2393                                 ret = btrfs_insert_empty_item(trans, root, path,
2394                                                               &new_key, size);
2395                                 BUG_ON(ret);
2396
2397                                 if (skip) {
2398                                         u32 start =
2399                                           btrfs_file_extent_calc_inline_size(0);
2400                                         memmove(buf+start, buf+start+skip,
2401                                                 datal);
2402                                 }
2403
2404                                 leaf = path->nodes[0];
2405                                 slot = path->slots[0];
2406                                 write_extent_buffer(leaf, buf,
2407                                             btrfs_item_ptr_offset(leaf, slot),
2408                                             size);
2409                                 inode_add_bytes(inode, datal);
2410                         }
2411
2412                         btrfs_mark_buffer_dirty(leaf);
2413                         btrfs_release_path(path);
2414
2415                         inode->i_mtime = inode->i_ctime = CURRENT_TIME;
2416
2417                         /*
2418                          * we round up to the block size at eof when
2419                          * determining which extents to clone above,
2420                          * but shouldn't round up the file size
2421                          */
2422                         endoff = new_key.offset + datal;
2423                         if (endoff > destoff+olen)
2424                                 endoff = destoff+olen;
2425                         if (endoff > inode->i_size)
2426                                 btrfs_i_size_write(inode, endoff);
2427
2428                         BTRFS_I(inode)->flags = BTRFS_I(src)->flags;
2429                         ret = btrfs_update_inode(trans, root, inode);
2430                         BUG_ON(ret);
2431                         btrfs_end_transaction(trans, root);
2432                 }
2433 next:
2434                 btrfs_release_path(path);
2435                 key.offset++;
2436         }
2437         ret = 0;
2438 out:
2439         btrfs_release_path(path);
2440         unlock_extent(&BTRFS_I(src)->io_tree, off, off+len, GFP_NOFS);
2441 out_unlock:
2442         mutex_unlock(&src->i_mutex);
2443         mutex_unlock(&inode->i_mutex);
2444         vfree(buf);
2445         btrfs_free_path(path);
2446 out_fput:
2447         fput(src_file);
2448 out_drop_write:
2449         mnt_drop_write(file->f_path.mnt);
2450         return ret;
2451 }
2452
2453 static long btrfs_ioctl_clone_range(struct file *file, void __user *argp)
2454 {
2455         struct btrfs_ioctl_clone_range_args args;
2456
2457         if (copy_from_user(&args, argp, sizeof(args)))
2458                 return -EFAULT;
2459         return btrfs_ioctl_clone(file, args.src_fd, args.src_offset,
2460                                  args.src_length, args.dest_offset);
2461 }
2462
2463 /*
2464  * there are many ways the trans_start and trans_end ioctls can lead
2465  * to deadlocks.  They should only be used by applications that
2466  * basically own the machine, and have a very in depth understanding
2467  * of all the possible deadlocks and enospc problems.
2468  */
2469 static long btrfs_ioctl_trans_start(struct file *file)
2470 {
2471         struct inode *inode = fdentry(file)->d_inode;
2472         struct btrfs_root *root = BTRFS_I(inode)->root;
2473         struct btrfs_trans_handle *trans;
2474         int ret;
2475
2476         ret = -EPERM;
2477         if (!capable(CAP_SYS_ADMIN))
2478                 goto out;
2479
2480         ret = -EINPROGRESS;
2481         if (file->private_data)
2482                 goto out;
2483
2484         ret = -EROFS;
2485         if (btrfs_root_readonly(root))
2486                 goto out;
2487
2488         ret = mnt_want_write(file->f_path.mnt);
2489         if (ret)
2490                 goto out;
2491
2492         atomic_inc(&root->fs_info->open_ioctl_trans);
2493
2494         ret = -ENOMEM;
2495         trans = btrfs_start_ioctl_transaction(root);
2496         if (IS_ERR(trans))
2497                 goto out_drop;
2498
2499         file->private_data = trans;
2500         return 0;
2501
2502 out_drop:
2503         atomic_dec(&root->fs_info->open_ioctl_trans);
2504         mnt_drop_write(file->f_path.mnt);
2505 out:
2506         return ret;
2507 }
2508
2509 static long btrfs_ioctl_default_subvol(struct file *file, void __user *argp)
2510 {
2511         struct inode *inode = fdentry(file)->d_inode;
2512         struct btrfs_root *root = BTRFS_I(inode)->root;
2513         struct btrfs_root *new_root;
2514         struct btrfs_dir_item *di;
2515         struct btrfs_trans_handle *trans;
2516         struct btrfs_path *path;
2517         struct btrfs_key location;
2518         struct btrfs_disk_key disk_key;
2519         struct btrfs_super_block *disk_super;
2520         u64 features;
2521         u64 objectid = 0;
2522         u64 dir_id;
2523
2524         if (!capable(CAP_SYS_ADMIN))
2525                 return -EPERM;
2526
2527         if (copy_from_user(&objectid, argp, sizeof(objectid)))
2528                 return -EFAULT;
2529
2530         if (!objectid)
2531                 objectid = root->root_key.objectid;
2532
2533         location.objectid = objectid;
2534         location.type = BTRFS_ROOT_ITEM_KEY;
2535         location.offset = (u64)-1;
2536
2537         new_root = btrfs_read_fs_root_no_name(root->fs_info, &location);
2538         if (IS_ERR(new_root))
2539                 return PTR_ERR(new_root);
2540
2541         if (btrfs_root_refs(&new_root->root_item) == 0)
2542                 return -ENOENT;
2543
2544         path = btrfs_alloc_path();
2545         if (!path)
2546                 return -ENOMEM;
2547         path->leave_spinning = 1;
2548
2549         trans = btrfs_start_transaction(root, 1);
2550         if (IS_ERR(trans)) {
2551                 btrfs_free_path(path);
2552                 return PTR_ERR(trans);
2553         }
2554
2555         dir_id = btrfs_super_root_dir(&root->fs_info->super_copy);
2556         di = btrfs_lookup_dir_item(trans, root->fs_info->tree_root, path,
2557                                    dir_id, "default", 7, 1);
2558         if (IS_ERR_OR_NULL(di)) {
2559                 btrfs_free_path(path);
2560                 btrfs_end_transaction(trans, root);
2561                 printk(KERN_ERR "Umm, you don't have the default dir item, "
2562                        "this isn't going to work\n");
2563                 return -ENOENT;
2564         }
2565
2566         btrfs_cpu_key_to_disk(&disk_key, &new_root->root_key);
2567         btrfs_set_dir_item_key(path->nodes[0], di, &disk_key);
2568         btrfs_mark_buffer_dirty(path->nodes[0]);
2569         btrfs_free_path(path);
2570
2571         disk_super = &root->fs_info->super_copy;
2572         features = btrfs_super_incompat_flags(disk_super);
2573         if (!(features & BTRFS_FEATURE_INCOMPAT_DEFAULT_SUBVOL)) {
2574                 features |= BTRFS_FEATURE_INCOMPAT_DEFAULT_SUBVOL;
2575                 btrfs_set_super_incompat_flags(disk_super, features);
2576         }
2577         btrfs_end_transaction(trans, root);
2578
2579         return 0;
2580 }
2581
2582 static void get_block_group_info(struct list_head *groups_list,
2583                                  struct btrfs_ioctl_space_info *space)
2584 {
2585         struct btrfs_block_group_cache *block_group;
2586
2587         space->total_bytes = 0;
2588         space->used_bytes = 0;
2589         space->flags = 0;
2590         list_for_each_entry(block_group, groups_list, list) {
2591                 space->flags = block_group->flags;
2592                 space->total_bytes += block_group->key.offset;
2593                 space->used_bytes +=
2594                         btrfs_block_group_used(&block_group->item);
2595         }
2596 }
2597
2598 long btrfs_ioctl_space_info(struct btrfs_root *root, void __user *arg)
2599 {
2600         struct btrfs_ioctl_space_args space_args;
2601         struct btrfs_ioctl_space_info space;
2602         struct btrfs_ioctl_space_info *dest;
2603         struct btrfs_ioctl_space_info *dest_orig;
2604         struct btrfs_ioctl_space_info __user *user_dest;
2605         struct btrfs_space_info *info;
2606         u64 types[] = {BTRFS_BLOCK_GROUP_DATA,
2607                        BTRFS_BLOCK_GROUP_SYSTEM,
2608                        BTRFS_BLOCK_GROUP_METADATA,
2609                        BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA};
2610         int num_types = 4;
2611         int alloc_size;
2612         int ret = 0;
2613         u64 slot_count = 0;
2614         int i, c;
2615
2616         if (copy_from_user(&space_args,
2617                            (struct btrfs_ioctl_space_args __user *)arg,
2618                            sizeof(space_args)))
2619                 return -EFAULT;
2620
2621         for (i = 0; i < num_types; i++) {
2622                 struct btrfs_space_info *tmp;
2623
2624                 info = NULL;
2625                 rcu_read_lock();
2626                 list_for_each_entry_rcu(tmp, &root->fs_info->space_info,
2627                                         list) {
2628                         if (tmp->flags == types[i]) {
2629                                 info = tmp;
2630                                 break;
2631                         }
2632                 }
2633                 rcu_read_unlock();
2634
2635                 if (!info)
2636                         continue;
2637
2638                 down_read(&info->groups_sem);
2639                 for (c = 0; c < BTRFS_NR_RAID_TYPES; c++) {
2640                         if (!list_empty(&info->block_groups[c]))
2641                                 slot_count++;
2642                 }
2643                 up_read(&info->groups_sem);
2644         }
2645
2646         /* space_slots == 0 means they are asking for a count */
2647         if (space_args.space_slots == 0) {
2648                 space_args.total_spaces = slot_count;
2649                 goto out;
2650         }
2651
2652         slot_count = min_t(u64, space_args.space_slots, slot_count);
2653
2654         alloc_size = sizeof(*dest) * slot_count;
2655
2656         /* we generally have at most 6 or so space infos, one for each raid
2657          * level.  So, a whole page should be more than enough for everyone
2658          */
2659         if (alloc_size > PAGE_CACHE_SIZE)
2660                 return -ENOMEM;
2661
2662         space_args.total_spaces = 0;
2663         dest = kmalloc(alloc_size, GFP_NOFS);
2664         if (!dest)
2665                 return -ENOMEM;
2666         dest_orig = dest;
2667
2668         /* now we have a buffer to copy into */
2669         for (i = 0; i < num_types; i++) {
2670                 struct btrfs_space_info *tmp;
2671
2672                 if (!slot_count)
2673                         break;
2674
2675                 info = NULL;
2676                 rcu_read_lock();
2677                 list_for_each_entry_rcu(tmp, &root->fs_info->space_info,
2678                                         list) {
2679                         if (tmp->flags == types[i]) {
2680                                 info = tmp;
2681                                 break;
2682                         }
2683                 }
2684                 rcu_read_unlock();
2685
2686                 if (!info)
2687                         continue;
2688                 down_read(&info->groups_sem);
2689                 for (c = 0; c < BTRFS_NR_RAID_TYPES; c++) {
2690                         if (!list_empty(&info->block_groups[c])) {
2691                                 get_block_group_info(&info->block_groups[c],
2692                                                      &space);
2693                                 memcpy(dest, &space, sizeof(space));
2694                                 dest++;
2695                                 space_args.total_spaces++;
2696                                 slot_count--;
2697                         }
2698                         if (!slot_count)
2699                                 break;
2700                 }
2701                 up_read(&info->groups_sem);
2702         }
2703
2704         user_dest = (struct btrfs_ioctl_space_info *)
2705                 (arg + sizeof(struct btrfs_ioctl_space_args));
2706
2707         if (copy_to_user(user_dest, dest_orig, alloc_size))
2708                 ret = -EFAULT;
2709
2710         kfree(dest_orig);
2711 out:
2712         if (ret == 0 && copy_to_user(arg, &space_args, sizeof(space_args)))
2713                 ret = -EFAULT;
2714
2715         return ret;
2716 }
2717
2718 /*
2719  * there are many ways the trans_start and trans_end ioctls can lead
2720  * to deadlocks.  They should only be used by applications that
2721  * basically own the machine, and have a very in depth understanding
2722  * of all the possible deadlocks and enospc problems.
2723  */
2724 long btrfs_ioctl_trans_end(struct file *file)
2725 {
2726         struct inode *inode = fdentry(file)->d_inode;
2727         struct btrfs_root *root = BTRFS_I(inode)->root;
2728         struct btrfs_trans_handle *trans;
2729
2730         trans = file->private_data;
2731         if (!trans)
2732                 return -EINVAL;
2733         file->private_data = NULL;
2734
2735         btrfs_end_transaction(trans, root);
2736
2737         atomic_dec(&root->fs_info->open_ioctl_trans);
2738
2739         mnt_drop_write(file->f_path.mnt);
2740         return 0;
2741 }
2742
2743 static noinline long btrfs_ioctl_start_sync(struct file *file, void __user *argp)
2744 {
2745         struct btrfs_root *root = BTRFS_I(file->f_dentry->d_inode)->root;
2746         struct btrfs_trans_handle *trans;
2747         u64 transid;
2748         int ret;
2749
2750         trans = btrfs_start_transaction(root, 0);
2751         if (IS_ERR(trans))
2752                 return PTR_ERR(trans);
2753         transid = trans->transid;
2754         ret = btrfs_commit_transaction_async(trans, root, 0);
2755         if (ret) {
2756                 btrfs_end_transaction(trans, root);
2757                 return ret;
2758         }
2759
2760         if (argp)
2761                 if (copy_to_user(argp, &transid, sizeof(transid)))
2762                         return -EFAULT;
2763         return 0;
2764 }
2765
2766 static noinline long btrfs_ioctl_wait_sync(struct file *file, void __user *argp)
2767 {
2768         struct btrfs_root *root = BTRFS_I(file->f_dentry->d_inode)->root;
2769         u64 transid;
2770
2771         if (argp) {
2772                 if (copy_from_user(&transid, argp, sizeof(transid)))
2773                         return -EFAULT;
2774         } else {
2775                 transid = 0;  /* current trans */
2776         }
2777         return btrfs_wait_for_commit(root, transid);
2778 }
2779
2780 static long btrfs_ioctl_scrub(struct btrfs_root *root, void __user *arg)
2781 {
2782         int ret;
2783         struct btrfs_ioctl_scrub_args *sa;
2784
2785         if (!capable(CAP_SYS_ADMIN))
2786                 return -EPERM;
2787
2788         sa = memdup_user(arg, sizeof(*sa));
2789         if (IS_ERR(sa))
2790                 return PTR_ERR(sa);
2791
2792         ret = btrfs_scrub_dev(root, sa->devid, sa->start, sa->end,
2793                               &sa->progress, sa->flags & BTRFS_SCRUB_READONLY);
2794
2795         if (copy_to_user(arg, sa, sizeof(*sa)))
2796                 ret = -EFAULT;
2797
2798         kfree(sa);
2799         return ret;
2800 }
2801
2802 static long btrfs_ioctl_scrub_cancel(struct btrfs_root *root, void __user *arg)
2803 {
2804         if (!capable(CAP_SYS_ADMIN))
2805                 return -EPERM;
2806
2807         return btrfs_scrub_cancel(root);
2808 }
2809
2810 static long btrfs_ioctl_scrub_progress(struct btrfs_root *root,
2811                                        void __user *arg)
2812 {
2813         struct btrfs_ioctl_scrub_args *sa;
2814         int ret;
2815
2816         if (!capable(CAP_SYS_ADMIN))
2817                 return -EPERM;
2818
2819         sa = memdup_user(arg, sizeof(*sa));
2820         if (IS_ERR(sa))
2821                 return PTR_ERR(sa);
2822
2823         ret = btrfs_scrub_progress(root, sa->devid, &sa->progress);
2824
2825         if (copy_to_user(arg, sa, sizeof(*sa)))
2826                 ret = -EFAULT;
2827
2828         kfree(sa);
2829         return ret;
2830 }
2831
2832 long btrfs_ioctl(struct file *file, unsigned int
2833                 cmd, unsigned long arg)
2834 {
2835         struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root;
2836         void __user *argp = (void __user *)arg;
2837
2838         switch (cmd) {
2839         case FS_IOC_GETFLAGS:
2840                 return btrfs_ioctl_getflags(file, argp);
2841         case FS_IOC_SETFLAGS:
2842                 return btrfs_ioctl_setflags(file, argp);
2843         case FS_IOC_GETVERSION:
2844                 return btrfs_ioctl_getversion(file, argp);
2845         case FITRIM:
2846                 return btrfs_ioctl_fitrim(file, argp);
2847         case BTRFS_IOC_SNAP_CREATE:
2848                 return btrfs_ioctl_snap_create(file, argp, 0);
2849         case BTRFS_IOC_SNAP_CREATE_V2:
2850                 return btrfs_ioctl_snap_create_v2(file, argp, 0);
2851         case BTRFS_IOC_SUBVOL_CREATE:
2852                 return btrfs_ioctl_snap_create(file, argp, 1);
2853         case BTRFS_IOC_SNAP_DESTROY:
2854                 return btrfs_ioctl_snap_destroy(file, argp);
2855         case BTRFS_IOC_SUBVOL_GETFLAGS:
2856                 return btrfs_ioctl_subvol_getflags(file, argp);
2857         case BTRFS_IOC_SUBVOL_SETFLAGS:
2858                 return btrfs_ioctl_subvol_setflags(file, argp);
2859         case BTRFS_IOC_DEFAULT_SUBVOL:
2860                 return btrfs_ioctl_default_subvol(file, argp);
2861         case BTRFS_IOC_DEFRAG:
2862                 return btrfs_ioctl_defrag(file, NULL);
2863         case BTRFS_IOC_DEFRAG_RANGE:
2864                 return btrfs_ioctl_defrag(file, argp);
2865         case BTRFS_IOC_RESIZE:
2866                 return btrfs_ioctl_resize(root, argp);
2867         case BTRFS_IOC_ADD_DEV:
2868                 return btrfs_ioctl_add_dev(root, argp);
2869         case BTRFS_IOC_RM_DEV:
2870                 return btrfs_ioctl_rm_dev(root, argp);
2871         case BTRFS_IOC_FS_INFO:
2872                 return btrfs_ioctl_fs_info(root, argp);
2873         case BTRFS_IOC_DEV_INFO:
2874                 return btrfs_ioctl_dev_info(root, argp);
2875         case BTRFS_IOC_BALANCE:
2876                 return btrfs_balance(root->fs_info->dev_root);
2877         case BTRFS_IOC_CLONE:
2878                 return btrfs_ioctl_clone(file, arg, 0, 0, 0);
2879         case BTRFS_IOC_CLONE_RANGE:
2880                 return btrfs_ioctl_clone_range(file, argp);
2881         case BTRFS_IOC_TRANS_START:
2882                 return btrfs_ioctl_trans_start(file);
2883         case BTRFS_IOC_TRANS_END:
2884                 return btrfs_ioctl_trans_end(file);
2885         case BTRFS_IOC_TREE_SEARCH:
2886                 return btrfs_ioctl_tree_search(file, argp);
2887         case BTRFS_IOC_INO_LOOKUP:
2888                 return btrfs_ioctl_ino_lookup(file, argp);
2889         case BTRFS_IOC_SPACE_INFO:
2890                 return btrfs_ioctl_space_info(root, argp);
2891         case BTRFS_IOC_SYNC:
2892                 btrfs_sync_fs(file->f_dentry->d_sb, 1);
2893                 return 0;
2894         case BTRFS_IOC_START_SYNC:
2895                 return btrfs_ioctl_start_sync(file, argp);
2896         case BTRFS_IOC_WAIT_SYNC:
2897                 return btrfs_ioctl_wait_sync(file, argp);
2898         case BTRFS_IOC_SCRUB:
2899                 return btrfs_ioctl_scrub(root, argp);
2900         case BTRFS_IOC_SCRUB_CANCEL:
2901                 return btrfs_ioctl_scrub_cancel(root, argp);
2902         case BTRFS_IOC_SCRUB_PROGRESS:
2903                 return btrfs_ioctl_scrub_progress(root, argp);
2904         }
2905
2906         return -ENOTTY;
2907 }