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/smp_lock.h>
  31 #include <linux/backing-dev.h>
  32 #include <linux/mount.h>
  33 #include <linux/mpage.h>
  34 #include <linux/namei.h>
  35 #include <linux/swap.h>
  36 #include <linux/writeback.h>
  37 #include <linux/statfs.h>
  38 #include <linux/compat.h>
  39 #include <linux/bit_spinlock.h>
  40 #include <linux/security.h>
  41 #include <linux/version.h>
  42 #include <linux/xattr.h>
  43 #include <linux/vmalloc.h>
  44 #include "ctree.h"
  45 #include "disk-io.h"
  46 #include "transaction.h"
  47 #include "btrfs_inode.h"
  48 #include "ioctl.h"
  49 #include "print-tree.h"
  50 #include "volumes.h"
  51 #include "locking.h"
  52
  53
  54
  55 static noinline int create_subvol(struct btrfs_root *root,
  56                                   struct dentry *dentry,
  57                                   char *name, int namelen)
  58 {
  59         struct btrfs_trans_handle *trans;
  60         struct btrfs_key key;
  61         struct btrfs_root_item root_item;
  62         struct btrfs_inode_item *inode_item;
  63         struct extent_buffer *leaf;
  64         struct btrfs_root *new_root = root;
  65         struct inode *dir;
  66         int ret;
  67         int err;
  68         u64 objectid;
  69         u64 new_dirid = BTRFS_FIRST_FREE_OBJECTID;
  70         unsigned long nr = 1;
  71
  72         ret = btrfs_check_free_space(root, 1, 0);
  73         if (ret)
  74                 goto fail_commit;
  75
  76         trans = btrfs_start_transaction(root, 1);
  77         BUG_ON(!trans);
  78
  79         ret = btrfs_find_free_objectid(trans, root->fs_info->tree_root,
  80                                        0, &objectid);
  81         if (ret)
  82                 goto fail;
  83
  84         leaf = btrfs_alloc_free_block(trans, root, root->leafsize, 0,
  85                                       objectid, trans->transid, 0, 0, 0);
  86         if (IS_ERR(leaf)) {
  87                 ret = PTR_ERR(leaf);
  88                 goto fail;
  89         }
  90
  91         btrfs_set_header_nritems(leaf, 0);
  92         btrfs_set_header_level(leaf, 0);
  93         btrfs_set_header_bytenr(leaf, leaf->start);
  94         btrfs_set_header_generation(leaf, trans->transid);
  95         btrfs_set_header_owner(leaf, objectid);
  96
  97         write_extent_buffer(leaf, root->fs_info->fsid,
  98                             (unsigned long)btrfs_header_fsid(leaf),
  99                             BTRFS_FSID_SIZE);
 100         btrfs_mark_buffer_dirty(leaf);
 101
 102         inode_item = &root_item.inode;
 103         memset(inode_item, 0, sizeof(*inode_item));
 104         inode_item->generation = cpu_to_le64(1);
 105         inode_item->size = cpu_to_le64(3);
 106         inode_item->nlink = cpu_to_le32(1);
 107         inode_item->nbytes = cpu_to_le64(root->leafsize);
 108         inode_item->mode = cpu_to_le32(S_IFDIR | 0755);
 109
 110         btrfs_set_root_bytenr(&root_item, leaf->start);
 111         btrfs_set_root_generation(&root_item, trans->transid);
 112         btrfs_set_root_level(&root_item, 0);
 113         btrfs_set_root_refs(&root_item, 1);
 114         btrfs_set_root_used(&root_item, 0);
 115         btrfs_set_root_last_snapshot(&root_item, 0);
 116
 117         memset(&root_item.drop_progress, 0, sizeof(root_item.drop_progress));
 118         root_item.drop_level = 0;
 119
 120         btrfs_tree_unlock(leaf);
 121         free_extent_buffer(leaf);
 122         leaf = NULL;
 123
 124         btrfs_set_root_dirid(&root_item, new_dirid);
 125
 126         key.objectid = objectid;
 127         key.offset = 1;
 128         btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
 129         ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key,
 130                                 &root_item);
 131         if (ret)
 132                 goto fail;
 133
 134         /*
 135          * insert the directory item
 136          */
 137         key.offset = (u64)-1;
 138         dir = root->fs_info->sb->s_root->d_inode;
 139         ret = btrfs_insert_dir_item(trans, root->fs_info->tree_root,
 140                                     name, namelen, dir->i_ino, &key,
 141                                     BTRFS_FT_DIR, 0);
 142         if (ret)
 143                 goto fail;
 144
 145         ret = btrfs_insert_inode_ref(trans, root->fs_info->tree_root,
 146                              name, namelen, objectid,
 147                              root->fs_info->sb->s_root->d_inode->i_ino, 0);
 148         if (ret)
 149                 goto fail;
 150
 151         ret = btrfs_commit_transaction(trans, root);
 152         if (ret)
 153                 goto fail_commit;
 154
 155         new_root = btrfs_read_fs_root(root->fs_info, &key, name, namelen);
 156         BUG_ON(!new_root);
 157
 158         trans = btrfs_start_transaction(new_root, 1);
 159         BUG_ON(!trans);
 160
 161         ret = btrfs_create_subvol_root(new_root, dentry, trans, new_dirid,
 162                                        BTRFS_I(dir)->block_group);
 163         if (ret)
 164                 goto fail;
 165
 166 fail:
 167         nr = trans->blocks_used;
 168         err = btrfs_commit_transaction(trans, new_root);
 169         if (err && !ret)
 170                 ret = err;
 171 fail_commit:
 172         btrfs_btree_balance_dirty(root, nr);
 173         return ret;
 174 }
 175
 176 static int create_snapshot(struct btrfs_root *root, char *name, int namelen)
 177 {
 178         struct btrfs_pending_snapshot *pending_snapshot;
 179         struct btrfs_trans_handle *trans;
 180         int ret;
 181         int err;
 182         unsigned long nr = 0;
 183
 184         if (!root->ref_cows)
 185                 return -EINVAL;
 186
 187         ret = btrfs_check_free_space(root, 1, 0);
 188         if (ret)
 189                 goto fail_unlock;
 190
 191         pending_snapshot = kmalloc(sizeof(*pending_snapshot), GFP_NOFS);
 192         if (!pending_snapshot) {
 193                 ret = -ENOMEM;
 194                 goto fail_unlock;
 195         }
 196         pending_snapshot->name = kmalloc(namelen + 1, GFP_NOFS);
 197         if (!pending_snapshot->name) {
 198                 ret = -ENOMEM;
 199                 kfree(pending_snapshot);
 200                 goto fail_unlock;
 201         }
 202         memcpy(pending_snapshot->name, name, namelen);
 203         pending_snapshot->name[namelen] = '\0';
 204         trans = btrfs_start_transaction(root, 1);
 205         BUG_ON(!trans);
 206         pending_snapshot->root = root;
 207         list_add(&pending_snapshot->list,
 208                  &trans->transaction->pending_snapshots);
 209         ret = btrfs_update_inode(trans, root, root->inode);
 210         err = btrfs_commit_transaction(trans, root);
 211
 212 fail_unlock:
 213         btrfs_btree_balance_dirty(root, nr);
 214         return ret;
 215 }
 216
 217 /* copy of may_create in fs/namei.c() */
 218 static inline int btrfs_may_create(struct inode *dir, struct dentry *child)
 219 {
 220         if (child->d_inode)
 221                 return -EEXIST;
 222         if (IS_DEADDIR(dir))
 223                 return -ENOENT;
 224         return inode_permission(dir, MAY_WRITE | MAY_EXEC);
 225 }
 226
 227 /*
 228  * Create a new subvolume below @parent.  This is largely modeled after
 229  * sys_mkdirat and vfs_mkdir, but we only do a single component lookup
 230  * inside this filesystem so it's quite a bit simpler.
 231  */
 232 static noinline int btrfs_mksubvol(struct path *parent, char *name,
 233                                    int mode, int namelen)
 234 {
 235         struct dentry *dentry;
 236         int error;
 237
 238         mutex_lock_nested(&parent->dentry->d_inode->i_mutex, I_MUTEX_PARENT);
 239
 240         dentry = lookup_one_len(name, parent->dentry, namelen);
 241         error = PTR_ERR(dentry);
 242         if (IS_ERR(dentry))
 243                 goto out_unlock;
 244
 245         error = -EEXIST;
 246         if (dentry->d_inode)
 247                 goto out_dput;
 248
 249         if (!IS_POSIXACL(parent->dentry->d_inode))
 250                 mode &= ~current->fs->umask;
 251         error = mnt_want_write(parent->mnt);
 252         if (error)
 253                 goto out_dput;
 254
 255         error = btrfs_may_create(parent->dentry->d_inode, dentry);
 256         if (error)
 257                 goto out_drop_write;
 258
 259         /*
 260          * Actually perform the low-level subvolume creation after all
 261          * this VFS fuzz.
 262          *
 263          * Eventually we want to pass in an inode under which we create this
 264          * subvolume, but for now all are under the filesystem root.
 265          *
 266          * Also we should pass on the mode eventually to allow creating new
 267          * subvolume with specific mode bits.
 268          */
 269         error = create_subvol(BTRFS_I(parent->dentry->d_inode)->root, dentry,
 270                               name, namelen);
 271         if (error)
 272                 goto out_drop_write;
 273
 274         fsnotify_mkdir(parent->dentry->d_inode, dentry);
 275 out_drop_write:
 276         mnt_drop_write(parent->mnt);
 277 out_dput:
 278         dput(dentry);
 279 out_unlock:
 280         mutex_unlock(&parent->dentry->d_inode->i_mutex);
 281         return error;
 282 }
 283
 284
 285 int btrfs_defrag_file(struct file *file)
 286 {
 287         struct inode *inode = fdentry(file)->d_inode;
 288         struct btrfs_root *root = BTRFS_I(inode)->root;
 289         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
 290         struct btrfs_ordered_extent *ordered;
 291         struct page *page;
 292         unsigned long last_index;
 293         unsigned long ra_pages = root->fs_info->bdi.ra_pages;
 294         unsigned long total_read = 0;
 295         u64 page_start;
 296         u64 page_end;
 297         unsigned long i;
 298         int ret;
 299
 300         ret = btrfs_check_free_space(root, inode->i_size, 0);
 301         if (ret)
 302                 return -ENOSPC;
 303
 304         mutex_lock(&inode->i_mutex);
 305         last_index = inode->i_size >> PAGE_CACHE_SHIFT;
 306         for (i = 0; i <= last_index; i++) {
 307                 if (total_read % ra_pages == 0) {
 308                         btrfs_force_ra(inode->i_mapping, &file->f_ra, file, i,
 309                                        min(last_index, i + ra_pages - 1));
 310                 }
 311                 total_read++;
 312 again:
 313                 page = grab_cache_page(inode->i_mapping, i);
 314                 if (!page)
 315                         goto out_unlock;
 316                 if (!PageUptodate(page)) {
 317                         btrfs_readpage(NULL, page);
 318                         lock_page(page);
 319                         if (!PageUptodate(page)) {
 320                                 unlock_page(page);
 321                                 page_cache_release(page);
 322                                 goto out_unlock;
 323                         }
 324                 }
 325
 326                 wait_on_page_writeback(page);
 327
 328                 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
 329                 page_end = page_start + PAGE_CACHE_SIZE - 1;
 330                 lock_extent(io_tree, page_start, page_end, GFP_NOFS);
 331
 332                 ordered = btrfs_lookup_ordered_extent(inode, page_start);
 333                 if (ordered) {
 334                         unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
 335                         unlock_page(page);
 336                         page_cache_release(page);
 337                         btrfs_start_ordered_extent(inode, ordered, 1);
 338                         btrfs_put_ordered_extent(ordered);
 339                         goto again;
 340                 }
 341                 set_page_extent_mapped(page);
 342
 343                 /*
 344                  * this makes sure page_mkwrite is called on the
 345                  * page if it is dirtied again later
 346                  */
 347                 clear_page_dirty_for_io(page);
 348
 349                 btrfs_set_extent_delalloc(inode, page_start, page_end);
 350
 351                 unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
 352                 set_page_dirty(page);
 353                 unlock_page(page);
 354                 page_cache_release(page);
 355                 balance_dirty_pages_ratelimited_nr(inode->i_mapping, 1);
 356         }
 357
 358 out_unlock:
 359         mutex_unlock(&inode->i_mutex);
 360         return 0;
 361 }
 362
 363 /*
 364  * Called inside transaction, so use GFP_NOFS
 365  */
 366
 367 static int btrfs_ioctl_resize(struct btrfs_root *root, void __user *arg)
 368 {
 369         u64 new_size;
 370         u64 old_size;
 371         u64 devid = 1;
 372         struct btrfs_ioctl_vol_args *vol_args;
 373         struct btrfs_trans_handle *trans;
 374         struct btrfs_device *device = NULL;
 375         char *sizestr;
 376         char *devstr = NULL;
 377         int ret = 0;
 378         int namelen;
 379         int mod = 0;
 380
 381         vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);
 382
 383         if (!vol_args)
 384                 return -ENOMEM;
 385
 386         if (copy_from_user(vol_args, arg, sizeof(*vol_args))) {
 387                 ret = -EFAULT;
 388                 goto out;
 389         }
 390
 391         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
 392         namelen = strlen(vol_args->name);
 393
 394         mutex_lock(&root->fs_info->volume_mutex);
 395         sizestr = vol_args->name;
 396         devstr = strchr(sizestr, ':');
 397         if (devstr) {
 398                 char *end;
 399                 sizestr = devstr + 1;
 400                 *devstr = '\0';
 401                 devstr = vol_args->name;
 402                 devid = simple_strtoull(devstr, &end, 10);
 403                 printk(KERN_INFO "resizing devid %llu\n", devid);
 404         }
 405         device = btrfs_find_device(root, devid, NULL);
 406         if (!device) {
 407                 printk(KERN_INFO "resizer unable to find device %llu\n", devid);
 408                 ret = -EINVAL;
 409                 goto out_unlock;
 410         }
 411         if (!strcmp(sizestr, "max"))
 412                 new_size = device->bdev->bd_inode->i_size;
 413         else {
 414                 if (sizestr[0] == '-') {
 415                         mod = -1;
 416                         sizestr++;
 417                 } else if (sizestr[0] == '+') {
 418                         mod = 1;
 419                         sizestr++;
 420                 }
 421                 new_size = btrfs_parse_size(sizestr);
 422                 if (new_size == 0) {
 423                         ret = -EINVAL;
 424                         goto out_unlock;
 425                 }
 426         }
 427
 428         old_size = device->total_bytes;
 429
 430         if (mod < 0) {
 431                 if (new_size > old_size) {
 432                         ret = -EINVAL;
 433                         goto out_unlock;
 434                 }
 435                 new_size = old_size - new_size;
 436         } else if (mod > 0) {
 437                 new_size = old_size + new_size;
 438         }
 439
 440         if (new_size < 256 * 1024 * 1024) {
 441                 ret = -EINVAL;
 442                 goto out_unlock;
 443         }
 444         if (new_size > device->bdev->bd_inode->i_size) {
 445                 ret = -EFBIG;
 446                 goto out_unlock;
 447         }
 448
 449         do_div(new_size, root->sectorsize);
 450         new_size *= root->sectorsize;
 451
 452         printk(KERN_INFO "new size for %s is %llu\n",
 453                 device->name, (unsigned long long)new_size);
 454
 455         if (new_size > old_size) {
 456                 trans = btrfs_start_transaction(root, 1);
 457                 ret = btrfs_grow_device(trans, device, new_size);
 458                 btrfs_commit_transaction(trans, root);
 459         } else {
 460                 ret = btrfs_shrink_device(device, new_size);
 461         }
 462
 463 out_unlock:
 464         mutex_unlock(&root->fs_info->volume_mutex);
 465 out:
 466         kfree(vol_args);
 467         return ret;
 468 }
 469
 470 static noinline int btrfs_ioctl_snap_create(struct file *file,
 471                                             void __user *arg)
 472 {
 473         struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root;
 474         struct btrfs_ioctl_vol_args *vol_args;
 475         struct btrfs_dir_item *di;
 476         struct btrfs_path *path;
 477         u64 root_dirid;
 478         int namelen;
 479         int ret;
 480
 481         vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);
 482
 483         if (!vol_args)
 484                 return -ENOMEM;
 485
 486         if (copy_from_user(vol_args, arg, sizeof(*vol_args))) {
 487                 ret = -EFAULT;
 488                 goto out;
 489         }
 490
 491         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
 492         namelen = strlen(vol_args->name);
 493         if (strchr(vol_args->name, '/')) {
 494                 ret = -EINVAL;
 495                 goto out;
 496         }
 497
 498         path = btrfs_alloc_path();
 499         if (!path) {
 500                 ret = -ENOMEM;
 501                 goto out;
 502         }
 503
 504         root_dirid = root->fs_info->sb->s_root->d_inode->i_ino,
 505         di = btrfs_lookup_dir_item(NULL, root->fs_info->tree_root,
 506                             path, root_dirid,
 507                             vol_args->name, namelen, 0);
 508         btrfs_free_path(path);
 509
 510         if (di && !IS_ERR(di)) {
 511                 ret = -EEXIST;
 512                 goto out;
 513         }
 514
 515         if (IS_ERR(di)) {
 516                 ret = PTR_ERR(di);
 517                 goto out;
 518         }
 519
 520         if (root == root->fs_info->tree_root) {
 521                 ret = btrfs_mksubvol(&file->f_path, vol_args->name,
 522                                      file->f_path.dentry->d_inode->i_mode,
 523                                      namelen);
 524         } else {
 525                 ret = create_snapshot(root, vol_args->name, namelen);
 526         }
 527
 528 out:
 529         kfree(vol_args);
 530         return ret;
 531 }
 532
 533 static int btrfs_ioctl_defrag(struct file *file)
 534 {
 535         struct inode *inode = fdentry(file)->d_inode;
 536         struct btrfs_root *root = BTRFS_I(inode)->root;
 537
 538         switch (inode->i_mode & S_IFMT) {
 539         case S_IFDIR:
 540                 btrfs_defrag_root(root, 0);
 541                 btrfs_defrag_root(root->fs_info->extent_root, 0);
 542                 break;
 543         case S_IFREG:
 544                 btrfs_defrag_file(file);
 545                 break;
 546         }
 547
 548         return 0;
 549 }
 550
 551 long btrfs_ioctl_add_dev(struct btrfs_root *root, void __user *arg)
 552 {
 553         struct btrfs_ioctl_vol_args *vol_args;
 554         int ret;
 555
 556         vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);
 557
 558         if (!vol_args)
 559                 return -ENOMEM;
 560
 561         if (copy_from_user(vol_args, arg, sizeof(*vol_args))) {
 562                 ret = -EFAULT;
 563                 goto out;
 564         }
 565         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
 566         ret = btrfs_init_new_device(root, vol_args->name);
 567
 568 out:
 569         kfree(vol_args);
 570         return ret;
 571 }
 572
 573 long btrfs_ioctl_rm_dev(struct btrfs_root *root, void __user *arg)
 574 {
 575         struct btrfs_ioctl_vol_args *vol_args;
 576         int ret;
 577
 578         vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);
 579
 580         if (!vol_args)
 581                 return -ENOMEM;
 582
 583         if (copy_from_user(vol_args, arg, sizeof(*vol_args))) {
 584                 ret = -EFAULT;
 585                 goto out;
 586         }
 587         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
 588         ret = btrfs_rm_device(root, vol_args->name);
 589
 590 out:
 591         kfree(vol_args);
 592         return ret;
 593 }
 594
 595 long btrfs_ioctl_clone(struct file *file, unsigned long src_fd)
 596 {
 597         struct inode *inode = fdentry(file)->d_inode;
 598         struct btrfs_root *root = BTRFS_I(inode)->root;
 599         struct file *src_file;
 600         struct inode *src;
 601         struct btrfs_trans_handle *trans;
 602         struct btrfs_path *path;
 603         struct extent_buffer *leaf;
 604         char *buf;
 605         struct btrfs_key key;
 606         u32 nritems;
 607         int slot;
 608         int ret;
 609
 610         src_file = fget(src_fd);
 611         if (!src_file)
 612                 return -EBADF;
 613         src = src_file->f_dentry->d_inode;
 614
 615         ret = -EISDIR;
 616         if (S_ISDIR(src->i_mode) || S_ISDIR(inode->i_mode))
 617                 goto out_fput;
 618
 619         ret = -EXDEV;
 620         if (src->i_sb != inode->i_sb || BTRFS_I(src)->root != root)
 621                 goto out_fput;
 622
 623         ret = -ENOMEM;
 624         buf = vmalloc(btrfs_level_size(root, 0));
 625         if (!buf)
 626                 goto out_fput;
 627
 628         path = btrfs_alloc_path();
 629         if (!path) {
 630                 vfree(buf);
 631                 goto out_fput;
 632         }
 633         path->reada = 2;
 634
 635         if (inode < src) {
 636                 mutex_lock(&inode->i_mutex);
 637                 mutex_lock(&src->i_mutex);
 638         } else {
 639                 mutex_lock(&src->i_mutex);
 640                 mutex_lock(&inode->i_mutex);
 641         }
 642
 643         ret = -ENOTEMPTY;
 644         if (inode->i_size)
 645                 goto out_unlock;
 646
 647         /* do any pending delalloc/csum calc on src, one way or
 648            another, and lock file content */
 649         while (1) {
 650                 struct btrfs_ordered_extent *ordered;
 651                 lock_extent(&BTRFS_I(src)->io_tree, 0, (u64)-1, GFP_NOFS);
 652                 ordered = btrfs_lookup_first_ordered_extent(inode, (u64)-1);
 653                 if (BTRFS_I(src)->delalloc_bytes == 0 && !ordered)
 654                         break;
 655                 unlock_extent(&BTRFS_I(src)->io_tree, 0, (u64)-1, GFP_NOFS);
 656                 if (ordered)
 657                         btrfs_put_ordered_extent(ordered);
 658                 btrfs_wait_ordered_range(src, 0, (u64)-1);
 659         }
 660
 661         trans = btrfs_start_transaction(root, 1);
 662         BUG_ON(!trans);
 663
 664         key.objectid = src->i_ino;
 665         key.type = BTRFS_EXTENT_DATA_KEY;
 666         key.offset = 0;
 667
 668         while (1) {
 669                 /*
 670                  * note the key will change type as we walk through the
 671                  * tree.
 672                  */
 673                 ret = btrfs_search_slot(trans, root, &key, path, 0, 0);
 674                 if (ret < 0)
 675                         goto out;
 676
 677                 nritems = btrfs_header_nritems(path->nodes[0]);
 678                 if (path->slots[0] >= nritems) {
 679                         ret = btrfs_next_leaf(root, path);
 680                         if (ret < 0)
 681                                 goto out;
 682                         if (ret > 0)
 683                                 break;
 684                         nritems = btrfs_header_nritems(path->nodes[0]);
 685                 }
 686                 leaf = path->nodes[0];
 687                 slot = path->slots[0];
 688
 689                 btrfs_item_key_to_cpu(leaf, &key, slot);
 690                 if (btrfs_key_type(&key) > BTRFS_CSUM_ITEM_KEY ||
 691                     key.objectid != src->i_ino)
 692                         break;
 693
 694                 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY ||
 695                     btrfs_key_type(&key) == BTRFS_CSUM_ITEM_KEY) {
 696                         u32 size;
 697                         struct btrfs_key new_key;
 698
 699                         size = btrfs_item_size_nr(leaf, slot);
 700                         read_extent_buffer(leaf, buf,
 701                                            btrfs_item_ptr_offset(leaf, slot),
 702                                            size);
 703                         btrfs_release_path(root, path);
 704
 705                         memcpy(&new_key, &key, sizeof(new_key));
 706                         new_key.objectid = inode->i_ino;
 707                         ret = btrfs_insert_empty_item(trans, root, path,
 708                                                       &new_key, size);
 709                         if (ret)
 710                                 goto out;
 711
 712                         leaf = path->nodes[0];
 713                         slot = path->slots[0];
 714                         write_extent_buffer(leaf, buf,
 715                                             btrfs_item_ptr_offset(leaf, slot),
 716                                             size);
 717                         btrfs_mark_buffer_dirty(leaf);
 718                 }
 719
 720                 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) {
 721                         struct btrfs_file_extent_item *extent;
 722                         int found_type;
 723
 724                         extent = btrfs_item_ptr(leaf, slot,
 725                                                 struct btrfs_file_extent_item);
 726                         found_type = btrfs_file_extent_type(leaf, extent);
 727                         if (found_type == BTRFS_FILE_EXTENT_REG ||
 728                             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
 729                                 u64 ds = btrfs_file_extent_disk_bytenr(leaf,
 730                                                                        extent);
 731                                 u64 dl = btrfs_file_extent_disk_num_bytes(leaf,
 732                                                                  extent);
 733                                 /* ds == 0 means there's a hole */
 734                                 if (ds != 0) {
 735                                         ret = btrfs_inc_extent_ref(trans, root,
 736                                                      ds, dl, leaf->start,
 737                                                      root->root_key.objectid,
 738                                                      trans->transid,
 739                                                      inode->i_ino);
 740                                         BUG_ON(ret);
 741                                 }
 742                         }
 743                 }
 744                 btrfs_release_path(root, path);
 745                 key.offset++;
 746         }
 747         ret = 0;
 748 out:
 749         btrfs_release_path(root, path);
 750         if (ret == 0) {
 751                 inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 752                 inode_set_bytes(inode, inode_get_bytes(src));
 753                 btrfs_i_size_write(inode, src->i_size);
 754                 BTRFS_I(inode)->flags = BTRFS_I(src)->flags;
 755                 ret = btrfs_update_inode(trans, root, inode);
 756         }
 757         btrfs_end_transaction(trans, root);
 758         unlock_extent(&BTRFS_I(src)->io_tree, 0, (u64)-1, GFP_NOFS);
 759         if (ret)
 760                 vmtruncate(inode, 0);
 761 out_unlock:
 762         mutex_unlock(&src->i_mutex);
 763         mutex_unlock(&inode->i_mutex);
 764         vfree(buf);
 765         btrfs_free_path(path);
 766 out_fput:
 767         fput(src_file);
 768         return ret;
 769 }
 770
 771 /*
 772  * there are many ways the trans_start and trans_end ioctls can lead
 773  * to deadlocks.  They should only be used by applications that
 774  * basically own the machine, and have a very in depth understanding
 775  * of all the possible deadlocks and enospc problems.
 776  */
 777 long btrfs_ioctl_trans_start(struct file *file)
 778 {
 779         struct inode *inode = fdentry(file)->d_inode;
 780         struct btrfs_root *root = BTRFS_I(inode)->root;
 781         struct btrfs_trans_handle *trans;
 782         int ret = 0;
 783
 784         if (!capable(CAP_SYS_ADMIN))
 785                 return -EPERM;
 786
 787         if (file->private_data) {
 788                 ret = -EINPROGRESS;
 789                 goto out;
 790         }
 791
 792         mutex_lock(&root->fs_info->trans_mutex);
 793         root->fs_info->open_ioctl_trans++;
 794         mutex_unlock(&root->fs_info->trans_mutex);
 795
 796         trans = btrfs_start_ioctl_transaction(root, 0);
 797         if (trans)
 798                 file->private_data = trans;
 799         else
 800                 ret = -ENOMEM;
 801         /*printk(KERN_INFO "btrfs_ioctl_trans_start on %p\n", file);*/
 802 out:
 803         return ret;
 804 }
 805
 806 /*
 807  * there are many ways the trans_start and trans_end ioctls can lead
 808  * to deadlocks.  They should only be used by applications that
 809  * basically own the machine, and have a very in depth understanding
 810  * of all the possible deadlocks and enospc problems.
 811  */
 812 long btrfs_ioctl_trans_end(struct file *file)
 813 {
 814         struct inode *inode = fdentry(file)->d_inode;
 815         struct btrfs_root *root = BTRFS_I(inode)->root;
 816         struct btrfs_trans_handle *trans;
 817         int ret = 0;
 818
 819         trans = file->private_data;
 820         if (!trans) {
 821                 ret = -EINVAL;
 822                 goto out;
 823         }
 824         btrfs_end_transaction(trans, root);
 825         file->private_data = NULL;
 826
 827         mutex_lock(&root->fs_info->trans_mutex);
 828         root->fs_info->open_ioctl_trans--;
 829         mutex_unlock(&root->fs_info->trans_mutex);
 830
 831 out:
 832         return ret;
 833 }
 834
 835 long btrfs_ioctl(struct file *file, unsigned int
 836                 cmd, unsigned long arg)
 837 {
 838         struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root;
 839
 840         switch (cmd) {
 841         case BTRFS_IOC_SNAP_CREATE:
 842                 return btrfs_ioctl_snap_create(file, (void __user *)arg);
 843         case BTRFS_IOC_DEFRAG:
 844                 return btrfs_ioctl_defrag(file);
 845         case BTRFS_IOC_RESIZE:
 846                 return btrfs_ioctl_resize(root, (void __user *)arg);
 847         case BTRFS_IOC_ADD_DEV:
 848                 return btrfs_ioctl_add_dev(root, (void __user *)arg);
 849         case BTRFS_IOC_RM_DEV:
 850                 return btrfs_ioctl_rm_dev(root, (void __user *)arg);
 851         case BTRFS_IOC_BALANCE:
 852                 return btrfs_balance(root->fs_info->dev_root);
 853         case BTRFS_IOC_CLONE:
 854                 return btrfs_ioctl_clone(file, arg);
 855         case BTRFS_IOC_TRANS_START:
 856                 return btrfs_ioctl_trans_start(file);
 857         case BTRFS_IOC_TRANS_END:
 858                 return btrfs_ioctl_trans_end(file);
 859         case BTRFS_IOC_SYNC:
 860                 btrfs_start_delalloc_inodes(root);
 861                 btrfs_sync_fs(file->f_dentry->d_sb, 1);
 862                 return 0;
 863         }
 864
 865         return -ENOTTY;
 866 }