Btrfs: extent_map and data=ordered fixes for space balancing
[linux-2.6] / 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/pagemap.h>
25 #include <linux/highmem.h>
26 #include <linux/time.h>
27 #include <linux/init.h>
28 #include <linux/string.h>
29 #include <linux/smp_lock.h>
30 #include <linux/backing-dev.h>
31 #include <linux/mpage.h>
32 #include <linux/swap.h>
33 #include <linux/writeback.h>
34 #include <linux/statfs.h>
35 #include <linux/compat.h>
36 #include <linux/bit_spinlock.h>
37 #include <linux/version.h>
38 #include <linux/xattr.h>
39 #include <linux/vmalloc.h>
40 #include "ctree.h"
41 #include "disk-io.h"
42 #include "transaction.h"
43 #include "btrfs_inode.h"
44 #include "ioctl.h"
45 #include "print-tree.h"
46 #include "volumes.h"
47 #include "locking.h"
48
49
50
51 static noinline int create_subvol(struct btrfs_root *root, char *name,
52                                   int namelen)
53 {
54         struct btrfs_trans_handle *trans;
55         struct btrfs_key key;
56         struct btrfs_root_item root_item;
57         struct btrfs_inode_item *inode_item;
58         struct extent_buffer *leaf;
59         struct btrfs_root *new_root = root;
60         struct inode *dir;
61         int ret;
62         int err;
63         u64 objectid;
64         u64 new_dirid = BTRFS_FIRST_FREE_OBJECTID;
65         unsigned long nr = 1;
66
67         ret = btrfs_check_free_space(root, 1, 0);
68         if (ret)
69                 goto fail_commit;
70
71         trans = btrfs_start_transaction(root, 1);
72         BUG_ON(!trans);
73
74         ret = btrfs_find_free_objectid(trans, root->fs_info->tree_root,
75                                        0, &objectid);
76         if (ret)
77                 goto fail;
78
79         leaf = btrfs_alloc_free_block(trans, root, root->leafsize, 0,
80                                       objectid, trans->transid, 0, 0, 0);
81         if (IS_ERR(leaf)) {
82                 ret = PTR_ERR(leaf);
83                 goto fail;
84         }
85
86         btrfs_set_header_nritems(leaf, 0);
87         btrfs_set_header_level(leaf, 0);
88         btrfs_set_header_bytenr(leaf, leaf->start);
89         btrfs_set_header_generation(leaf, trans->transid);
90         btrfs_set_header_owner(leaf, objectid);
91
92         write_extent_buffer(leaf, root->fs_info->fsid,
93                             (unsigned long)btrfs_header_fsid(leaf),
94                             BTRFS_FSID_SIZE);
95         btrfs_mark_buffer_dirty(leaf);
96
97         inode_item = &root_item.inode;
98         memset(inode_item, 0, sizeof(*inode_item));
99         inode_item->generation = cpu_to_le64(1);
100         inode_item->size = cpu_to_le64(3);
101         inode_item->nlink = cpu_to_le32(1);
102         inode_item->nblocks = cpu_to_le64(1);
103         inode_item->mode = cpu_to_le32(S_IFDIR | 0755);
104
105         btrfs_set_root_bytenr(&root_item, leaf->start);
106         btrfs_set_root_level(&root_item, 0);
107         btrfs_set_root_refs(&root_item, 1);
108         btrfs_set_root_used(&root_item, 0);
109
110         memset(&root_item.drop_progress, 0, sizeof(root_item.drop_progress));
111         root_item.drop_level = 0;
112
113         btrfs_tree_unlock(leaf);
114         free_extent_buffer(leaf);
115         leaf = NULL;
116
117         btrfs_set_root_dirid(&root_item, new_dirid);
118
119         key.objectid = objectid;
120         key.offset = 1;
121         btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
122         ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key,
123                                 &root_item);
124         if (ret)
125                 goto fail;
126
127         /*
128          * insert the directory item
129          */
130         key.offset = (u64)-1;
131         dir = root->fs_info->sb->s_root->d_inode;
132         ret = btrfs_insert_dir_item(trans, root->fs_info->tree_root,
133                                     name, namelen, dir->i_ino, &key,
134                                     BTRFS_FT_DIR, 0);
135         if (ret)
136                 goto fail;
137
138         ret = btrfs_insert_inode_ref(trans, root->fs_info->tree_root,
139                              name, namelen, objectid,
140                              root->fs_info->sb->s_root->d_inode->i_ino, 0);
141         if (ret)
142                 goto fail;
143
144         ret = btrfs_commit_transaction(trans, root);
145         if (ret)
146                 goto fail_commit;
147
148         new_root = btrfs_read_fs_root(root->fs_info, &key, name, namelen);
149         BUG_ON(!new_root);
150
151         trans = btrfs_start_transaction(new_root, 1);
152         BUG_ON(!trans);
153
154         ret = btrfs_create_subvol_root(new_root, trans, new_dirid,
155                                        BTRFS_I(dir)->block_group);
156         if (ret)
157                 goto fail;
158
159         /* Invalidate existing dcache entry for new subvolume. */
160         btrfs_invalidate_dcache_root(root, name, namelen);
161
162 fail:
163         nr = trans->blocks_used;
164         err = btrfs_commit_transaction(trans, new_root);
165         if (err && !ret)
166                 ret = err;
167 fail_commit:
168         btrfs_btree_balance_dirty(root, nr);
169         return ret;
170 }
171
172 static int create_snapshot(struct btrfs_root *root, char *name, int namelen)
173 {
174         struct btrfs_pending_snapshot *pending_snapshot;
175         struct btrfs_trans_handle *trans;
176         int ret;
177         int err;
178         unsigned long nr = 0;
179
180         if (!root->ref_cows)
181                 return -EINVAL;
182
183         ret = btrfs_check_free_space(root, 1, 0);
184         if (ret)
185                 goto fail_unlock;
186
187         pending_snapshot = kmalloc(sizeof(*pending_snapshot), GFP_NOFS);
188         if (!pending_snapshot) {
189                 ret = -ENOMEM;
190                 goto fail_unlock;
191         }
192         pending_snapshot->name = kmalloc(namelen + 1, GFP_NOFS);
193         if (!pending_snapshot->name) {
194                 ret = -ENOMEM;
195                 kfree(pending_snapshot);
196                 goto fail_unlock;
197         }
198         memcpy(pending_snapshot->name, name, namelen);
199         pending_snapshot->name[namelen] = '\0';
200         trans = btrfs_start_transaction(root, 1);
201         BUG_ON(!trans);
202         pending_snapshot->root = root;
203         list_add(&pending_snapshot->list,
204                  &trans->transaction->pending_snapshots);
205         ret = btrfs_update_inode(trans, root, root->inode);
206         err = btrfs_commit_transaction(trans, root);
207
208 fail_unlock:
209         btrfs_btree_balance_dirty(root, nr);
210         return ret;
211 }
212
213 int btrfs_defrag_file(struct file *file)
214 {
215         struct inode *inode = fdentry(file)->d_inode;
216         struct btrfs_root *root = BTRFS_I(inode)->root;
217         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
218         struct btrfs_ordered_extent *ordered;
219         struct page *page;
220         unsigned long last_index;
221         unsigned long ra_pages = root->fs_info->bdi.ra_pages;
222         unsigned long total_read = 0;
223         u64 page_start;
224         u64 page_end;
225         unsigned long i;
226         int ret;
227
228         ret = btrfs_check_free_space(root, inode->i_size, 0);
229         if (ret)
230                 return -ENOSPC;
231
232         mutex_lock(&inode->i_mutex);
233         last_index = inode->i_size >> PAGE_CACHE_SHIFT;
234         for (i = 0; i <= last_index; i++) {
235                 if (total_read % ra_pages == 0) {
236                         btrfs_force_ra(inode->i_mapping, &file->f_ra, file, i,
237                                        min(last_index, i + ra_pages - 1));
238                 }
239                 total_read++;
240 again:
241                 page = grab_cache_page(inode->i_mapping, i);
242                 if (!page)
243                         goto out_unlock;
244                 if (!PageUptodate(page)) {
245                         btrfs_readpage(NULL, page);
246                         lock_page(page);
247                         if (!PageUptodate(page)) {
248                                 unlock_page(page);
249                                 page_cache_release(page);
250                                 goto out_unlock;
251                         }
252                 }
253
254                 wait_on_page_writeback(page);
255
256                 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
257                 page_end = page_start + PAGE_CACHE_SIZE - 1;
258                 lock_extent(io_tree, page_start, page_end, GFP_NOFS);
259
260                 ordered = btrfs_lookup_ordered_extent(inode, page_start);
261                 if (ordered) {
262                         unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
263                         unlock_page(page);
264                         page_cache_release(page);
265                         btrfs_start_ordered_extent(inode, ordered, 1);
266                         btrfs_put_ordered_extent(ordered);
267                         goto again;
268                 }
269                 set_page_extent_mapped(page);
270
271                 /*
272                  * this makes sure page_mkwrite is called on the
273                  * page if it is dirtied again later
274                  */
275                 clear_page_dirty_for_io(page);
276
277                 btrfs_set_extent_delalloc(inode, page_start, page_end);
278
279                 unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
280                 set_page_dirty(page);
281                 unlock_page(page);
282                 page_cache_release(page);
283                 balance_dirty_pages_ratelimited_nr(inode->i_mapping, 1);
284         }
285
286 out_unlock:
287         mutex_unlock(&inode->i_mutex);
288         return 0;
289 }
290
291 /*
292  * Called inside transaction, so use GFP_NOFS
293  */
294
295 static int btrfs_ioctl_resize(struct btrfs_root *root, void __user *arg)
296 {
297         u64 new_size;
298         u64 old_size;
299         u64 devid = 1;
300         struct btrfs_ioctl_vol_args *vol_args;
301         struct btrfs_trans_handle *trans;
302         struct btrfs_device *device = NULL;
303         char *sizestr;
304         char *devstr = NULL;
305         int ret = 0;
306         int namelen;
307         int mod = 0;
308
309         vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);
310
311         if (!vol_args)
312                 return -ENOMEM;
313
314         if (copy_from_user(vol_args, arg, sizeof(*vol_args))) {
315                 ret = -EFAULT;
316                 goto out;
317         }
318
319         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
320         namelen = strlen(vol_args->name);
321
322         mutex_lock(&root->fs_info->volume_mutex);
323         sizestr = vol_args->name;
324         devstr = strchr(sizestr, ':');
325         if (devstr) {
326                 char *end;
327                 sizestr = devstr + 1;
328                 *devstr = '\0';
329                 devstr = vol_args->name;
330                 devid = simple_strtoull(devstr, &end, 10);
331                 printk(KERN_INFO "resizing devid %llu\n", devid);
332         }
333         device = btrfs_find_device(root, devid, NULL);
334         if (!device) {
335                 printk(KERN_INFO "resizer unable to find device %llu\n", devid);
336                 ret = -EINVAL;
337                 goto out_unlock;
338         }
339         if (!strcmp(sizestr, "max"))
340                 new_size = device->bdev->bd_inode->i_size;
341         else {
342                 if (sizestr[0] == '-') {
343                         mod = -1;
344                         sizestr++;
345                 } else if (sizestr[0] == '+') {
346                         mod = 1;
347                         sizestr++;
348                 }
349                 new_size = btrfs_parse_size(sizestr);
350                 if (new_size == 0) {
351                         ret = -EINVAL;
352                         goto out_unlock;
353                 }
354         }
355
356         old_size = device->total_bytes;
357
358         if (mod < 0) {
359                 if (new_size > old_size) {
360                         ret = -EINVAL;
361                         goto out_unlock;
362                 }
363                 new_size = old_size - new_size;
364         } else if (mod > 0) {
365                 new_size = old_size + new_size;
366         }
367
368         if (new_size < 256 * 1024 * 1024) {
369                 ret = -EINVAL;
370                 goto out_unlock;
371         }
372         if (new_size > device->bdev->bd_inode->i_size) {
373                 ret = -EFBIG;
374                 goto out_unlock;
375         }
376
377         do_div(new_size, root->sectorsize);
378         new_size *= root->sectorsize;
379
380         printk(KERN_INFO "new size for %s is %llu\n",
381                 device->name, (unsigned long long)new_size);
382
383         if (new_size > old_size) {
384                 trans = btrfs_start_transaction(root, 1);
385                 ret = btrfs_grow_device(trans, device, new_size);
386                 btrfs_commit_transaction(trans, root);
387         } else {
388                 ret = btrfs_shrink_device(device, new_size);
389         }
390
391 out_unlock:
392         mutex_unlock(&root->fs_info->volume_mutex);
393 out:
394         kfree(vol_args);
395         return ret;
396 }
397
398 static noinline int btrfs_ioctl_snap_create(struct btrfs_root *root,
399                                             void __user *arg)
400 {
401         struct btrfs_ioctl_vol_args *vol_args;
402         struct btrfs_dir_item *di;
403         struct btrfs_path *path;
404         u64 root_dirid;
405         int namelen;
406         int ret;
407
408         vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);
409
410         if (!vol_args)
411                 return -ENOMEM;
412
413         if (copy_from_user(vol_args, arg, sizeof(*vol_args))) {
414                 ret = -EFAULT;
415                 goto out;
416         }
417
418         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
419         namelen = strlen(vol_args->name);
420         if (strchr(vol_args->name, '/')) {
421                 ret = -EINVAL;
422                 goto out;
423         }
424
425         path = btrfs_alloc_path();
426         if (!path) {
427                 ret = -ENOMEM;
428                 goto out;
429         }
430
431         root_dirid = root->fs_info->sb->s_root->d_inode->i_ino,
432         di = btrfs_lookup_dir_item(NULL, root->fs_info->tree_root,
433                             path, root_dirid,
434                             vol_args->name, namelen, 0);
435         btrfs_free_path(path);
436
437         if (di && !IS_ERR(di)) {
438                 ret = -EEXIST;
439                 goto out;
440         }
441
442         if (IS_ERR(di)) {
443                 ret = PTR_ERR(di);
444                 goto out;
445         }
446
447         if (root == root->fs_info->tree_root)
448                 ret = create_subvol(root, vol_args->name, namelen);
449         else
450                 ret = create_snapshot(root, vol_args->name, namelen);
451 out:
452         kfree(vol_args);
453         return ret;
454 }
455
456 static int btrfs_ioctl_defrag(struct file *file)
457 {
458         struct inode *inode = fdentry(file)->d_inode;
459         struct btrfs_root *root = BTRFS_I(inode)->root;
460
461         switch (inode->i_mode & S_IFMT) {
462         case S_IFDIR:
463                 btrfs_defrag_root(root, 0);
464                 btrfs_defrag_root(root->fs_info->extent_root, 0);
465                 break;
466         case S_IFREG:
467                 btrfs_defrag_file(file);
468                 break;
469         }
470
471         return 0;
472 }
473
474 long btrfs_ioctl_add_dev(struct btrfs_root *root, void __user *arg)
475 {
476         struct btrfs_ioctl_vol_args *vol_args;
477         int ret;
478
479         vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);
480
481         if (!vol_args)
482                 return -ENOMEM;
483
484         if (copy_from_user(vol_args, arg, sizeof(*vol_args))) {
485                 ret = -EFAULT;
486                 goto out;
487         }
488         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
489         ret = btrfs_init_new_device(root, vol_args->name);
490
491 out:
492         kfree(vol_args);
493         return ret;
494 }
495
496 long btrfs_ioctl_rm_dev(struct btrfs_root *root, void __user *arg)
497 {
498         struct btrfs_ioctl_vol_args *vol_args;
499         int ret;
500
501         vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);
502
503         if (!vol_args)
504                 return -ENOMEM;
505
506         if (copy_from_user(vol_args, arg, sizeof(*vol_args))) {
507                 ret = -EFAULT;
508                 goto out;
509         }
510         vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
511         ret = btrfs_rm_device(root, vol_args->name);
512
513 out:
514         kfree(vol_args);
515         return ret;
516 }
517
518 long btrfs_ioctl_clone(struct file *file, unsigned long src_fd)
519 {
520         struct inode *inode = fdentry(file)->d_inode;
521         struct btrfs_root *root = BTRFS_I(inode)->root;
522         struct file *src_file;
523         struct inode *src;
524         struct btrfs_trans_handle *trans;
525         struct btrfs_path *path;
526         struct extent_buffer *leaf;
527         char *buf;
528         struct btrfs_key key;
529         u32 nritems;
530         int slot;
531         int ret;
532
533         src_file = fget(src_fd);
534         if (!src_file)
535                 return -EBADF;
536         src = src_file->f_dentry->d_inode;
537
538         ret = -EISDIR;
539         if (S_ISDIR(src->i_mode) || S_ISDIR(inode->i_mode))
540                 goto out_fput;
541
542         ret = -EXDEV;
543         if (src->i_sb != inode->i_sb || BTRFS_I(src)->root != root)
544                 goto out_fput;
545
546         ret = -ENOMEM;
547         buf = vmalloc(btrfs_level_size(root, 0));
548         if (!buf)
549                 goto out_fput;
550
551         path = btrfs_alloc_path();
552         if (!path) {
553                 vfree(buf);
554                 goto out_fput;
555         }
556         path->reada = 2;
557
558         if (inode < src) {
559                 mutex_lock(&inode->i_mutex);
560                 mutex_lock(&src->i_mutex);
561         } else {
562                 mutex_lock(&src->i_mutex);
563                 mutex_lock(&inode->i_mutex);
564         }
565
566         ret = -ENOTEMPTY;
567         if (inode->i_size)
568                 goto out_unlock;
569
570         /* do any pending delalloc/csum calc on src, one way or
571            another, and lock file content */
572         while (1) {
573                 struct btrfs_ordered_extent *ordered;
574                 lock_extent(&BTRFS_I(src)->io_tree, 0, (u64)-1, GFP_NOFS);
575                 ordered = btrfs_lookup_first_ordered_extent(inode, (u64)-1);
576                 if (BTRFS_I(src)->delalloc_bytes == 0 && !ordered)
577                         break;
578                 unlock_extent(&BTRFS_I(src)->io_tree, 0, (u64)-1, GFP_NOFS);
579                 if (ordered)
580                         btrfs_put_ordered_extent(ordered);
581                 btrfs_wait_ordered_range(src, 0, (u64)-1);
582         }
583
584         trans = btrfs_start_transaction(root, 1);
585         BUG_ON(!trans);
586
587         key.objectid = src->i_ino;
588         key.type = BTRFS_EXTENT_DATA_KEY;
589         key.offset = 0;
590
591         while (1) {
592                 /*
593                  * note the key will change type as we walk through the
594                  * tree.
595                  */
596                 ret = btrfs_search_slot(trans, root, &key, path, 0, 0);
597                 if (ret < 0)
598                         goto out;
599
600                 nritems = btrfs_header_nritems(path->nodes[0]);
601                 if (path->slots[0] >= nritems) {
602                         ret = btrfs_next_leaf(root, path);
603                         if (ret < 0)
604                                 goto out;
605                         if (ret > 0)
606                                 break;
607                         nritems = btrfs_header_nritems(path->nodes[0]);
608                 }
609                 leaf = path->nodes[0];
610                 slot = path->slots[0];
611
612                 btrfs_item_key_to_cpu(leaf, &key, slot);
613                 if (btrfs_key_type(&key) > BTRFS_CSUM_ITEM_KEY ||
614                     key.objectid != src->i_ino)
615                         break;
616
617                 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY ||
618                     btrfs_key_type(&key) == BTRFS_CSUM_ITEM_KEY) {
619                         u32 size;
620                         struct btrfs_key new_key;
621
622                         size = btrfs_item_size_nr(leaf, slot);
623                         read_extent_buffer(leaf, buf,
624                                            btrfs_item_ptr_offset(leaf, slot),
625                                            size);
626                         btrfs_release_path(root, path);
627
628                         memcpy(&new_key, &key, sizeof(new_key));
629                         new_key.objectid = inode->i_ino;
630                         ret = btrfs_insert_empty_item(trans, root, path,
631                                                       &new_key, size);
632                         if (ret)
633                                 goto out;
634
635                         leaf = path->nodes[0];
636                         slot = path->slots[0];
637                         write_extent_buffer(leaf, buf,
638                                             btrfs_item_ptr_offset(leaf, slot),
639                                             size);
640                         btrfs_mark_buffer_dirty(leaf);
641                 }
642
643                 if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) {
644                         struct btrfs_file_extent_item *extent;
645                         int found_type;
646
647                         extent = btrfs_item_ptr(leaf, slot,
648                                                 struct btrfs_file_extent_item);
649                         found_type = btrfs_file_extent_type(leaf, extent);
650                         if (found_type == BTRFS_FILE_EXTENT_REG) {
651                                 u64 ds = btrfs_file_extent_disk_bytenr(leaf,
652                                                                        extent);
653                                 u64 dl = btrfs_file_extent_disk_num_bytes(leaf,
654                                                                  extent);
655                                 /* ds == 0 means there's a hole */
656                                 if (ds != 0) {
657                                         ret = btrfs_inc_extent_ref(trans, root,
658                                                      ds, dl, leaf->start,
659                                                      root->root_key.objectid,
660                                                      trans->transid,
661                                                      inode->i_ino, key.offset);
662                                         BUG_ON(ret);
663                                 }
664                         }
665                 }
666                 btrfs_release_path(root, path);
667                 key.offset++;
668         }
669         ret = 0;
670 out:
671         btrfs_release_path(root, path);
672         if (ret == 0) {
673                 inode->i_mtime = inode->i_ctime = CURRENT_TIME;
674                 inode->i_blocks = src->i_blocks;
675                 btrfs_i_size_write(inode, src->i_size);
676                 BTRFS_I(inode)->flags = BTRFS_I(src)->flags;
677                 ret = btrfs_update_inode(trans, root, inode);
678         }
679         btrfs_end_transaction(trans, root);
680         unlock_extent(&BTRFS_I(src)->io_tree, 0, (u64)-1, GFP_NOFS);
681         if (ret)
682                 vmtruncate(inode, 0);
683 out_unlock:
684         mutex_unlock(&src->i_mutex);
685         mutex_unlock(&inode->i_mutex);
686         vfree(buf);
687         btrfs_free_path(path);
688 out_fput:
689         fput(src_file);
690         return ret;
691 }
692
693 /*
694  * there are many ways the trans_start and trans_end ioctls can lead
695  * to deadlocks.  They should only be used by applications that
696  * basically own the machine, and have a very in depth understanding
697  * of all the possible deadlocks and enospc problems.
698  */
699 long btrfs_ioctl_trans_start(struct file *file)
700 {
701         struct inode *inode = fdentry(file)->d_inode;
702         struct btrfs_root *root = BTRFS_I(inode)->root;
703         struct btrfs_trans_handle *trans;
704         int ret = 0;
705
706         if (!capable(CAP_SYS_ADMIN))
707                 return -EPERM;
708
709         if (file->private_data) {
710                 ret = -EINPROGRESS;
711                 goto out;
712         }
713
714         mutex_lock(&root->fs_info->trans_mutex);
715         root->fs_info->open_ioctl_trans++;
716         mutex_unlock(&root->fs_info->trans_mutex);
717
718         trans = btrfs_start_ioctl_transaction(root, 0);
719         if (trans)
720                 file->private_data = trans;
721         else
722                 ret = -ENOMEM;
723         /*printk(KERN_INFO "btrfs_ioctl_trans_start on %p\n", file);*/
724 out:
725         return ret;
726 }
727
728 /*
729  * there are many ways the trans_start and trans_end ioctls can lead
730  * to deadlocks.  They should only be used by applications that
731  * basically own the machine, and have a very in depth understanding
732  * of all the possible deadlocks and enospc problems.
733  */
734 long btrfs_ioctl_trans_end(struct file *file)
735 {
736         struct inode *inode = fdentry(file)->d_inode;
737         struct btrfs_root *root = BTRFS_I(inode)->root;
738         struct btrfs_trans_handle *trans;
739         int ret = 0;
740
741         trans = file->private_data;
742         if (!trans) {
743                 ret = -EINVAL;
744                 goto out;
745         }
746         btrfs_end_transaction(trans, root);
747         file->private_data = NULL;
748
749         mutex_lock(&root->fs_info->trans_mutex);
750         root->fs_info->open_ioctl_trans--;
751         mutex_unlock(&root->fs_info->trans_mutex);
752
753 out:
754         return ret;
755 }
756
757 long btrfs_ioctl(struct file *file, unsigned int
758                 cmd, unsigned long arg)
759 {
760         struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root;
761
762         switch (cmd) {
763         case BTRFS_IOC_SNAP_CREATE:
764                 return btrfs_ioctl_snap_create(root, (void __user *)arg);
765         case BTRFS_IOC_DEFRAG:
766                 return btrfs_ioctl_defrag(file);
767         case BTRFS_IOC_RESIZE:
768                 return btrfs_ioctl_resize(root, (void __user *)arg);
769         case BTRFS_IOC_ADD_DEV:
770                 return btrfs_ioctl_add_dev(root, (void __user *)arg);
771         case BTRFS_IOC_RM_DEV:
772                 return btrfs_ioctl_rm_dev(root, (void __user *)arg);
773         case BTRFS_IOC_BALANCE:
774                 return btrfs_balance(root->fs_info->dev_root);
775         case BTRFS_IOC_CLONE:
776                 return btrfs_ioctl_clone(file, arg);
777         case BTRFS_IOC_TRANS_START:
778                 return btrfs_ioctl_trans_start(file);
779         case BTRFS_IOC_TRANS_END:
780                 return btrfs_ioctl_trans_end(file);
781         case BTRFS_IOC_SYNC:
782                 btrfs_start_delalloc_inodes(root);
783                 btrfs_sync_fs(file->f_dentry->d_sb, 1);
784                 return 0;
785         }
786
787         return -ENOTTY;
788 }