Root/fs/btrfs/ioctl.c

1/*
2 * Copyright (C) 2007 Oracle. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18
19#include <linux/kernel.h>
20#include <linux/bio.h>
21#include <linux/buffer_head.h>
22#include <linux/file.h>
23#include <linux/fs.h>
24#include <linux/fsnotify.h>
25#include <linux/pagemap.h>
26#include <linux/highmem.h>
27#include <linux/time.h>
28#include <linux/init.h>
29#include <linux/string.h>
30#include <linux/backing-dev.h>
31#include <linux/mount.h>
32#include <linux/mpage.h>
33#include <linux/namei.h>
34#include <linux/swap.h>
35#include <linux/writeback.h>
36#include <linux/statfs.h>
37#include <linux/compat.h>
38#include <linux/bit_spinlock.h>
39#include <linux/security.h>
40#include <linux/xattr.h>
41#include <linux/vmalloc.h>
42#include <linux/slab.h>
43#include "compat.h"
44#include "ctree.h"
45#include "disk-io.h"
46#include "transaction.h"
47#include "btrfs_inode.h"
48#include "ioctl.h"
49#include "print-tree.h"
50#include "volumes.h"
51#include "locking.h"
52
53/* Mask out flags that are inappropriate for the given type of inode. */
54static inline __u32 btrfs_mask_flags(umode_t mode, __u32 flags)
55{
56    if (S_ISDIR(mode))
57        return flags;
58    else if (S_ISREG(mode))
59        return flags & ~FS_DIRSYNC_FL;
60    else
61        return flags & (FS_NODUMP_FL | FS_NOATIME_FL);
62}
63
64/*
65 * Export inode flags to the format expected by the FS_IOC_GETFLAGS ioctl.
66 */
67static unsigned int btrfs_flags_to_ioctl(unsigned int flags)
68{
69    unsigned int iflags = 0;
70
71    if (flags & BTRFS_INODE_SYNC)
72        iflags |= FS_SYNC_FL;
73    if (flags & BTRFS_INODE_IMMUTABLE)
74        iflags |= FS_IMMUTABLE_FL;
75    if (flags & BTRFS_INODE_APPEND)
76        iflags |= FS_APPEND_FL;
77    if (flags & BTRFS_INODE_NODUMP)
78        iflags |= FS_NODUMP_FL;
79    if (flags & BTRFS_INODE_NOATIME)
80        iflags |= FS_NOATIME_FL;
81    if (flags & BTRFS_INODE_DIRSYNC)
82        iflags |= FS_DIRSYNC_FL;
83
84    return iflags;
85}
86
87/*
88 * Update inode->i_flags based on the btrfs internal flags.
89 */
90void btrfs_update_iflags(struct inode *inode)
91{
92    struct btrfs_inode *ip = BTRFS_I(inode);
93
94    inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
95
96    if (ip->flags & BTRFS_INODE_SYNC)
97        inode->i_flags |= S_SYNC;
98    if (ip->flags & BTRFS_INODE_IMMUTABLE)
99        inode->i_flags |= S_IMMUTABLE;
100    if (ip->flags & BTRFS_INODE_APPEND)
101        inode->i_flags |= S_APPEND;
102    if (ip->flags & BTRFS_INODE_NOATIME)
103        inode->i_flags |= S_NOATIME;
104    if (ip->flags & BTRFS_INODE_DIRSYNC)
105        inode->i_flags |= S_DIRSYNC;
106}
107
108/*
109 * Inherit flags from the parent inode.
110 *
111 * Unlike extN we don't have any flags we don't want to inherit currently.
112 */
113void btrfs_inherit_iflags(struct inode *inode, struct inode *dir)
114{
115    unsigned int flags;
116
117    if (!dir)
118        return;
119
120    flags = BTRFS_I(dir)->flags;
121
122    if (S_ISREG(inode->i_mode))
123        flags &= ~BTRFS_INODE_DIRSYNC;
124    else if (!S_ISDIR(inode->i_mode))
125        flags &= (BTRFS_INODE_NODUMP | BTRFS_INODE_NOATIME);
126
127    BTRFS_I(inode)->flags = flags;
128    btrfs_update_iflags(inode);
129}
130
131static int btrfs_ioctl_getflags(struct file *file, void __user *arg)
132{
133    struct btrfs_inode *ip = BTRFS_I(file->f_path.dentry->d_inode);
134    unsigned int flags = btrfs_flags_to_ioctl(ip->flags);
135
136    if (copy_to_user(arg, &flags, sizeof(flags)))
137        return -EFAULT;
138    return 0;
139}
140
141static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
142{
143    struct inode *inode = file->f_path.dentry->d_inode;
144    struct btrfs_inode *ip = BTRFS_I(inode);
145    struct btrfs_root *root = ip->root;
146    struct btrfs_trans_handle *trans;
147    unsigned int flags, oldflags;
148    int ret;
149
150    if (copy_from_user(&flags, arg, sizeof(flags)))
151        return -EFAULT;
152
153    if (flags & ~(FS_IMMUTABLE_FL | FS_APPEND_FL | \
154              FS_NOATIME_FL | FS_NODUMP_FL | \
155              FS_SYNC_FL | FS_DIRSYNC_FL))
156        return -EOPNOTSUPP;
157
158    if (!is_owner_or_cap(inode))
159        return -EACCES;
160
161    mutex_lock(&inode->i_mutex);
162
163    flags = btrfs_mask_flags(inode->i_mode, flags);
164    oldflags = btrfs_flags_to_ioctl(ip->flags);
165    if ((flags ^ oldflags) & (FS_APPEND_FL | FS_IMMUTABLE_FL)) {
166        if (!capable(CAP_LINUX_IMMUTABLE)) {
167            ret = -EPERM;
168            goto out_unlock;
169        }
170    }
171
172    ret = mnt_want_write(file->f_path.mnt);
173    if (ret)
174        goto out_unlock;
175
176    if (flags & FS_SYNC_FL)
177        ip->flags |= BTRFS_INODE_SYNC;
178    else
179        ip->flags &= ~BTRFS_INODE_SYNC;
180    if (flags & FS_IMMUTABLE_FL)
181        ip->flags |= BTRFS_INODE_IMMUTABLE;
182    else
183        ip->flags &= ~BTRFS_INODE_IMMUTABLE;
184    if (flags & FS_APPEND_FL)
185        ip->flags |= BTRFS_INODE_APPEND;
186    else
187        ip->flags &= ~BTRFS_INODE_APPEND;
188    if (flags & FS_NODUMP_FL)
189        ip->flags |= BTRFS_INODE_NODUMP;
190    else
191        ip->flags &= ~BTRFS_INODE_NODUMP;
192    if (flags & FS_NOATIME_FL)
193        ip->flags |= BTRFS_INODE_NOATIME;
194    else
195        ip->flags &= ~BTRFS_INODE_NOATIME;
196    if (flags & FS_DIRSYNC_FL)
197        ip->flags |= BTRFS_INODE_DIRSYNC;
198    else
199        ip->flags &= ~BTRFS_INODE_DIRSYNC;
200
201
202    trans = btrfs_join_transaction(root, 1);
203    BUG_ON(!trans);
204
205    ret = btrfs_update_inode(trans, root, inode);
206    BUG_ON(ret);
207
208    btrfs_update_iflags(inode);
209    inode->i_ctime = CURRENT_TIME;
210    btrfs_end_transaction(trans, root);
211
212    mnt_drop_write(file->f_path.mnt);
213 out_unlock:
214    mutex_unlock(&inode->i_mutex);
215    return 0;
216}
217
218static int btrfs_ioctl_getversion(struct file *file, int __user *arg)
219{
220    struct inode *inode = file->f_path.dentry->d_inode;
221
222    return put_user(inode->i_generation, arg);
223}
224
225static noinline int create_subvol(struct btrfs_root *root,
226                  struct dentry *dentry,
227                  char *name, int namelen)
228{
229    struct btrfs_trans_handle *trans;
230    struct btrfs_key key;
231    struct btrfs_root_item root_item;
232    struct btrfs_inode_item *inode_item;
233    struct extent_buffer *leaf;
234    struct btrfs_root *new_root;
235    struct inode *dir = dentry->d_parent->d_inode;
236    int ret;
237    int err;
238    u64 objectid;
239    u64 new_dirid = BTRFS_FIRST_FREE_OBJECTID;
240    u64 index = 0;
241
242    /*
243     * 1 - inode item
244     * 2 - refs
245     * 1 - root item
246     * 2 - dir items
247     */
248    ret = btrfs_reserve_metadata_space(root, 6);
249    if (ret)
250        return ret;
251
252    trans = btrfs_start_transaction(root, 1);
253    BUG_ON(!trans);
254
255    ret = btrfs_find_free_objectid(trans, root->fs_info->tree_root,
256                       0, &objectid);
257    if (ret)
258        goto fail;
259
260    leaf = btrfs_alloc_free_block(trans, root, root->leafsize,
261                      0, objectid, NULL, 0, 0, 0);
262    if (IS_ERR(leaf)) {
263        ret = PTR_ERR(leaf);
264        goto fail;
265    }
266
267    memset_extent_buffer(leaf, 0, 0, sizeof(struct btrfs_header));
268    btrfs_set_header_bytenr(leaf, leaf->start);
269    btrfs_set_header_generation(leaf, trans->transid);
270    btrfs_set_header_backref_rev(leaf, BTRFS_MIXED_BACKREF_REV);
271    btrfs_set_header_owner(leaf, objectid);
272
273    write_extent_buffer(leaf, root->fs_info->fsid,
274                (unsigned long)btrfs_header_fsid(leaf),
275                BTRFS_FSID_SIZE);
276    write_extent_buffer(leaf, root->fs_info->chunk_tree_uuid,
277                (unsigned long)btrfs_header_chunk_tree_uuid(leaf),
278                BTRFS_UUID_SIZE);
279    btrfs_mark_buffer_dirty(leaf);
280
281    inode_item = &root_item.inode;
282    memset(inode_item, 0, sizeof(*inode_item));
283    inode_item->generation = cpu_to_le64(1);
284    inode_item->size = cpu_to_le64(3);
285    inode_item->nlink = cpu_to_le32(1);
286    inode_item->nbytes = cpu_to_le64(root->leafsize);
287    inode_item->mode = cpu_to_le32(S_IFDIR | 0755);
288
289    btrfs_set_root_bytenr(&root_item, leaf->start);
290    btrfs_set_root_generation(&root_item, trans->transid);
291    btrfs_set_root_level(&root_item, 0);
292    btrfs_set_root_refs(&root_item, 1);
293    btrfs_set_root_used(&root_item, leaf->len);
294    btrfs_set_root_last_snapshot(&root_item, 0);
295
296    memset(&root_item.drop_progress, 0, sizeof(root_item.drop_progress));
297    root_item.drop_level = 0;
298
299    btrfs_tree_unlock(leaf);
300    free_extent_buffer(leaf);
301    leaf = NULL;
302
303    btrfs_set_root_dirid(&root_item, new_dirid);
304
305    key.objectid = objectid;
306    key.offset = 0;
307    btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
308    ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key,
309                &root_item);
310    if (ret)
311        goto fail;
312
313    key.offset = (u64)-1;
314    new_root = btrfs_read_fs_root_no_name(root->fs_info, &key);
315    BUG_ON(IS_ERR(new_root));
316
317    btrfs_record_root_in_trans(trans, new_root);
318
319    ret = btrfs_create_subvol_root(trans, new_root, new_dirid,
320                       BTRFS_I(dir)->block_group);
321    /*
322     * insert the directory item
323     */
324    ret = btrfs_set_inode_index(dir, &index);
325    BUG_ON(ret);
326
327    ret = btrfs_insert_dir_item(trans, root,
328                    name, namelen, dir->i_ino, &key,
329                    BTRFS_FT_DIR, index);
330    if (ret)
331        goto fail;
332
333    btrfs_i_size_write(dir, dir->i_size + namelen * 2);
334    ret = btrfs_update_inode(trans, root, dir);
335    BUG_ON(ret);
336
337    ret = btrfs_add_root_ref(trans, root->fs_info->tree_root,
338                 objectid, root->root_key.objectid,
339                 dir->i_ino, index, name, namelen);
340
341    BUG_ON(ret);
342
343    d_instantiate(dentry, btrfs_lookup_dentry(dir, dentry));
344fail:
345    err = btrfs_commit_transaction(trans, root);
346    if (err && !ret)
347        ret = err;
348
349    btrfs_unreserve_metadata_space(root, 6);
350    return ret;
351}
352
353static int create_snapshot(struct btrfs_root *root, struct dentry *dentry,
354               char *name, int namelen)
355{
356    struct inode *inode;
357    struct btrfs_pending_snapshot *pending_snapshot;
358    struct btrfs_trans_handle *trans;
359    int ret;
360
361    if (!root->ref_cows)
362        return -EINVAL;
363
364    /*
365     * 1 - inode item
366     * 2 - refs
367     * 1 - root item
368     * 2 - dir items
369     */
370    ret = btrfs_reserve_metadata_space(root, 6);
371    if (ret)
372        goto fail;
373
374    pending_snapshot = kzalloc(sizeof(*pending_snapshot), GFP_NOFS);
375    if (!pending_snapshot) {
376        ret = -ENOMEM;
377        btrfs_unreserve_metadata_space(root, 6);
378        goto fail;
379    }
380    pending_snapshot->name = kmalloc(namelen + 1, GFP_NOFS);
381    if (!pending_snapshot->name) {
382        ret = -ENOMEM;
383        kfree(pending_snapshot);
384        btrfs_unreserve_metadata_space(root, 6);
385        goto fail;
386    }
387    memcpy(pending_snapshot->name, name, namelen);
388    pending_snapshot->name[namelen] = '\0';
389    pending_snapshot->dentry = dentry;
390    trans = btrfs_start_transaction(root, 1);
391    BUG_ON(!trans);
392    pending_snapshot->root = root;
393    list_add(&pending_snapshot->list,
394         &trans->transaction->pending_snapshots);
395    ret = btrfs_commit_transaction(trans, root);
396    BUG_ON(ret);
397    btrfs_unreserve_metadata_space(root, 6);
398
399    inode = btrfs_lookup_dentry(dentry->d_parent->d_inode, dentry);
400    if (IS_ERR(inode)) {
401        ret = PTR_ERR(inode);
402        goto fail;
403    }
404    BUG_ON(!inode);
405    d_instantiate(dentry, inode);
406    ret = 0;
407fail:
408    return ret;
409}
410
411/* copy of may_create in fs/namei.c() */
412static inline int btrfs_may_create(struct inode *dir, struct dentry *child)
413{
414    if (child->d_inode)
415        return -EEXIST;
416    if (IS_DEADDIR(dir))
417        return -ENOENT;
418    return inode_permission(dir, MAY_WRITE | MAY_EXEC);
419}
420
421/*
422 * Create a new subvolume below @parent. This is largely modeled after
423 * sys_mkdirat and vfs_mkdir, but we only do a single component lookup
424 * inside this filesystem so it's quite a bit simpler.
425 */
426static noinline int btrfs_mksubvol(struct path *parent,
427                   char *name, int namelen,
428                   struct btrfs_root *snap_src)
429{
430    struct inode *dir = parent->dentry->d_inode;
431    struct dentry *dentry;
432    int error;
433
434    mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
435
436    dentry = lookup_one_len(name, parent->dentry, namelen);
437    error = PTR_ERR(dentry);
438    if (IS_ERR(dentry))
439        goto out_unlock;
440
441    error = -EEXIST;
442    if (dentry->d_inode)
443        goto out_dput;
444
445    error = mnt_want_write(parent->mnt);
446    if (error)
447        goto out_dput;
448
449    error = btrfs_may_create(dir, dentry);
450    if (error)
451        goto out_drop_write;
452
453    down_read(&BTRFS_I(dir)->root->fs_info->subvol_sem);
454
455    if (btrfs_root_refs(&BTRFS_I(dir)->root->root_item) == 0)
456        goto out_up_read;
457
458    if (snap_src) {
459        error = create_snapshot(snap_src, dentry,
460                    name, namelen);
461    } else {
462        error = create_subvol(BTRFS_I(dir)->root, dentry,
463                      name, namelen);
464    }
465    if (!error)
466        fsnotify_mkdir(dir, dentry);
467out_up_read:
468    up_read(&BTRFS_I(dir)->root->fs_info->subvol_sem);
469out_drop_write:
470    mnt_drop_write(parent->mnt);
471out_dput:
472    dput(dentry);
473out_unlock:
474    mutex_unlock(&dir->i_mutex);
475    return error;
476}
477
478static int should_defrag_range(struct inode *inode, u64 start, u64 len,
479                   int thresh, u64 *last_len, u64 *skip,
480                   u64 *defrag_end)
481{
482    struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
483    struct extent_map *em = NULL;
484    struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
485    int ret = 1;
486
487
488    if (thresh == 0)
489        thresh = 256 * 1024;
490
491    /*
492     * make sure that once we start defragging and extent, we keep on
493     * defragging it
494     */
495    if (start < *defrag_end)
496        return 1;
497
498    *skip = 0;
499
500    /*
501     * hopefully we have this extent in the tree already, try without
502     * the full extent lock
503     */
504    read_lock(&em_tree->lock);
505    em = lookup_extent_mapping(em_tree, start, len);
506    read_unlock(&em_tree->lock);
507
508    if (!em) {
509        /* get the big lock and read metadata off disk */
510        lock_extent(io_tree, start, start + len - 1, GFP_NOFS);
511        em = btrfs_get_extent(inode, NULL, 0, start, len, 0);
512        unlock_extent(io_tree, start, start + len - 1, GFP_NOFS);
513
514        if (IS_ERR(em))
515            return 0;
516    }
517
518    /* this will cover holes, and inline extents */
519    if (em->block_start >= EXTENT_MAP_LAST_BYTE)
520        ret = 0;
521
522    /*
523     * we hit a real extent, if it is big don't bother defragging it again
524     */
525    if ((*last_len == 0 || *last_len >= thresh) && em->len >= thresh)
526        ret = 0;
527
528    /*
529     * last_len ends up being a counter of how many bytes we've defragged.
530     * every time we choose not to defrag an extent, we reset *last_len
531     * so that the next tiny extent will force a defrag.
532     *
533     * The end result of this is that tiny extents before a single big
534     * extent will force at least part of that big extent to be defragged.
535     */
536    if (ret) {
537        *last_len += len;
538        *defrag_end = extent_map_end(em);
539    } else {
540        *last_len = 0;
541        *skip = extent_map_end(em);
542        *defrag_end = 0;
543    }
544
545    free_extent_map(em);
546    return ret;
547}
548
549static int btrfs_defrag_file(struct file *file,
550                 struct btrfs_ioctl_defrag_range_args *range)
551{
552    struct inode *inode = fdentry(file)->d_inode;
553    struct btrfs_root *root = BTRFS_I(inode)->root;
554    struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
555    struct btrfs_ordered_extent *ordered;
556    struct page *page;
557    unsigned long last_index;
558    unsigned long ra_pages = root->fs_info->bdi.ra_pages;
559    unsigned long total_read = 0;
560    u64 page_start;
561    u64 page_end;
562    u64 last_len = 0;
563    u64 skip = 0;
564    u64 defrag_end = 0;
565    unsigned long i;
566    int ret;
567
568    if (inode->i_size == 0)
569        return 0;
570
571    if (range->start + range->len > range->start) {
572        last_index = min_t(u64, inode->i_size - 1,
573             range->start + range->len - 1) >> PAGE_CACHE_SHIFT;
574    } else {
575        last_index = (inode->i_size - 1) >> PAGE_CACHE_SHIFT;
576    }
577
578    i = range->start >> PAGE_CACHE_SHIFT;
579    while (i <= last_index) {
580        if (!should_defrag_range(inode, (u64)i << PAGE_CACHE_SHIFT,
581                    PAGE_CACHE_SIZE,
582                    range->extent_thresh,
583                    &last_len, &skip,
584                    &defrag_end)) {
585            unsigned long next;
586            /*
587             * the should_defrag function tells us how much to skip
588             * bump our counter by the suggested amount
589             */
590            next = (skip + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
591            i = max(i + 1, next);
592            continue;
593        }
594
595        if (total_read % ra_pages == 0) {
596            btrfs_force_ra(inode->i_mapping, &file->f_ra, file, i,
597                       min(last_index, i + ra_pages - 1));
598        }
599        total_read++;
600        mutex_lock(&inode->i_mutex);
601        if (range->flags & BTRFS_DEFRAG_RANGE_COMPRESS)
602            BTRFS_I(inode)->force_compress = 1;
603
604        ret = btrfs_check_data_free_space(root, inode, PAGE_CACHE_SIZE);
605        if (ret) {
606            ret = -ENOSPC;
607            break;
608        }
609
610        ret = btrfs_reserve_metadata_for_delalloc(root, inode, 1);
611        if (ret) {
612            btrfs_free_reserved_data_space(root, inode,
613                               PAGE_CACHE_SIZE);
614            ret = -ENOSPC;
615            break;
616        }
617again:
618        if (inode->i_size == 0 ||
619            i > ((inode->i_size - 1) >> PAGE_CACHE_SHIFT)) {
620            ret = 0;
621            goto err_reservations;
622        }
623
624        page = grab_cache_page(inode->i_mapping, i);
625        if (!page)
626            goto err_reservations;
627
628        if (!PageUptodate(page)) {
629            btrfs_readpage(NULL, page);
630            lock_page(page);
631            if (!PageUptodate(page)) {
632                unlock_page(page);
633                page_cache_release(page);
634                goto err_reservations;
635            }
636        }
637
638        if (page->mapping != inode->i_mapping) {
639            unlock_page(page);
640            page_cache_release(page);
641            goto again;
642        }
643
644        wait_on_page_writeback(page);
645
646        if (PageDirty(page)) {
647            btrfs_free_reserved_data_space(root, inode,
648                               PAGE_CACHE_SIZE);
649            goto loop_unlock;
650        }
651
652        page_start = (u64)page->index << PAGE_CACHE_SHIFT;
653        page_end = page_start + PAGE_CACHE_SIZE - 1;
654        lock_extent(io_tree, page_start, page_end, GFP_NOFS);
655
656        ordered = btrfs_lookup_ordered_extent(inode, page_start);
657        if (ordered) {
658            unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
659            unlock_page(page);
660            page_cache_release(page);
661            btrfs_start_ordered_extent(inode, ordered, 1);
662            btrfs_put_ordered_extent(ordered);
663            goto again;
664        }
665        set_page_extent_mapped(page);
666
667        /*
668         * this makes sure page_mkwrite is called on the
669         * page if it is dirtied again later
670         */
671        clear_page_dirty_for_io(page);
672        clear_extent_bits(&BTRFS_I(inode)->io_tree, page_start,
673                  page_end, EXTENT_DIRTY | EXTENT_DELALLOC |
674                  EXTENT_DO_ACCOUNTING, GFP_NOFS);
675
676        btrfs_set_extent_delalloc(inode, page_start, page_end, NULL);
677        ClearPageChecked(page);
678        set_page_dirty(page);
679        unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
680
681loop_unlock:
682        unlock_page(page);
683        page_cache_release(page);
684        mutex_unlock(&inode->i_mutex);
685
686        btrfs_unreserve_metadata_for_delalloc(root, inode, 1);
687        balance_dirty_pages_ratelimited_nr(inode->i_mapping, 1);
688        i++;
689    }
690
691    if ((range->flags & BTRFS_DEFRAG_RANGE_START_IO))
692        filemap_flush(inode->i_mapping);
693
694    if ((range->flags & BTRFS_DEFRAG_RANGE_COMPRESS)) {
695        /* the filemap_flush will queue IO into the worker threads, but
696         * we have to make sure the IO is actually started and that
697         * ordered extents get created before we return
698         */
699        atomic_inc(&root->fs_info->async_submit_draining);
700        while (atomic_read(&root->fs_info->nr_async_submits) ||
701              atomic_read(&root->fs_info->async_delalloc_pages)) {
702            wait_event(root->fs_info->async_submit_wait,
703               (atomic_read(&root->fs_info->nr_async_submits) == 0 &&
704                atomic_read(&root->fs_info->async_delalloc_pages) == 0));
705        }
706        atomic_dec(&root->fs_info->async_submit_draining);
707
708        mutex_lock(&inode->i_mutex);
709        BTRFS_I(inode)->force_compress = 0;
710        mutex_unlock(&inode->i_mutex);
711    }
712
713    return 0;
714
715err_reservations:
716    mutex_unlock(&inode->i_mutex);
717    btrfs_free_reserved_data_space(root, inode, PAGE_CACHE_SIZE);
718    btrfs_unreserve_metadata_for_delalloc(root, inode, 1);
719    return ret;
720}
721
722static noinline int btrfs_ioctl_resize(struct btrfs_root *root,
723                    void __user *arg)
724{
725    u64 new_size;
726    u64 old_size;
727    u64 devid = 1;
728    struct btrfs_ioctl_vol_args *vol_args;
729    struct btrfs_trans_handle *trans;
730    struct btrfs_device *device = NULL;
731    char *sizestr;
732    char *devstr = NULL;
733    int ret = 0;
734    int namelen;
735    int mod = 0;
736
737    if (root->fs_info->sb->s_flags & MS_RDONLY)
738        return -EROFS;
739
740    if (!capable(CAP_SYS_ADMIN))
741        return -EPERM;
742
743    vol_args = memdup_user(arg, sizeof(*vol_args));
744    if (IS_ERR(vol_args))
745        return PTR_ERR(vol_args);
746
747    vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
748    namelen = strlen(vol_args->name);
749
750    mutex_lock(&root->fs_info->volume_mutex);
751    sizestr = vol_args->name;
752    devstr = strchr(sizestr, ':');
753    if (devstr) {
754        char *end;
755        sizestr = devstr + 1;
756        *devstr = '\0';
757        devstr = vol_args->name;
758        devid = simple_strtoull(devstr, &end, 10);
759        printk(KERN_INFO "resizing devid %llu\n",
760               (unsigned long long)devid);
761    }
762    device = btrfs_find_device(root, devid, NULL, NULL);
763    if (!device) {
764        printk(KERN_INFO "resizer unable to find device %llu\n",
765               (unsigned long long)devid);
766        ret = -EINVAL;
767        goto out_unlock;
768    }
769    if (!strcmp(sizestr, "max"))
770        new_size = device->bdev->bd_inode->i_size;
771    else {
772        if (sizestr[0] == '-') {
773            mod = -1;
774            sizestr++;
775        } else if (sizestr[0] == '+') {
776            mod = 1;
777            sizestr++;
778        }
779        new_size = memparse(sizestr, NULL);
780        if (new_size == 0) {
781            ret = -EINVAL;
782            goto out_unlock;
783        }
784    }
785
786    old_size = device->total_bytes;
787
788    if (mod < 0) {
789        if (new_size > old_size) {
790            ret = -EINVAL;
791            goto out_unlock;
792        }
793        new_size = old_size - new_size;
794    } else if (mod > 0) {
795        new_size = old_size + new_size;
796    }
797
798    if (new_size < 256 * 1024 * 1024) {
799        ret = -EINVAL;
800        goto out_unlock;
801    }
802    if (new_size > device->bdev->bd_inode->i_size) {
803        ret = -EFBIG;
804        goto out_unlock;
805    }
806
807    do_div(new_size, root->sectorsize);
808    new_size *= root->sectorsize;
809
810    printk(KERN_INFO "new size for %s is %llu\n",
811        device->name, (unsigned long long)new_size);
812
813    if (new_size > old_size) {
814        trans = btrfs_start_transaction(root, 1);
815        ret = btrfs_grow_device(trans, device, new_size);
816        btrfs_commit_transaction(trans, root);
817    } else {
818        ret = btrfs_shrink_device(device, new_size);
819    }
820
821out_unlock:
822    mutex_unlock(&root->fs_info->volume_mutex);
823    kfree(vol_args);
824    return ret;
825}
826
827static noinline int btrfs_ioctl_snap_create(struct file *file,
828                        void __user *arg, int subvol)
829{
830    struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root;
831    struct btrfs_ioctl_vol_args *vol_args;
832    struct file *src_file;
833    int namelen;
834    int ret = 0;
835
836    if (root->fs_info->sb->s_flags & MS_RDONLY)
837        return -EROFS;
838
839    vol_args = memdup_user(arg, sizeof(*vol_args));
840    if (IS_ERR(vol_args))
841        return PTR_ERR(vol_args);
842
843    vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
844    namelen = strlen(vol_args->name);
845    if (strchr(vol_args->name, '/')) {
846        ret = -EINVAL;
847        goto out;
848    }
849
850    if (subvol) {
851        ret = btrfs_mksubvol(&file->f_path, vol_args->name, namelen,
852                     NULL);
853    } else {
854        struct inode *src_inode;
855        src_file = fget(vol_args->fd);
856        if (!src_file) {
857            ret = -EINVAL;
858            goto out;
859        }
860
861        src_inode = src_file->f_path.dentry->d_inode;
862        if (src_inode->i_sb != file->f_path.dentry->d_inode->i_sb) {
863            printk(KERN_INFO "btrfs: Snapshot src from "
864                   "another FS\n");
865            ret = -EINVAL;
866            fput(src_file);
867            goto out;
868        }
869        ret = btrfs_mksubvol(&file->f_path, vol_args->name, namelen,
870                     BTRFS_I(src_inode)->root);
871        fput(src_file);
872    }
873out:
874    kfree(vol_args);
875    return ret;
876}
877
878/*
879 * helper to check if the subvolume references other subvolumes
880 */
881static noinline int may_destroy_subvol(struct btrfs_root *root)
882{
883    struct btrfs_path *path;
884    struct btrfs_key key;
885    int ret;
886
887    path = btrfs_alloc_path();
888    if (!path)
889        return -ENOMEM;
890
891    key.objectid = root->root_key.objectid;
892    key.type = BTRFS_ROOT_REF_KEY;
893    key.offset = (u64)-1;
894
895    ret = btrfs_search_slot(NULL, root->fs_info->tree_root,
896                &key, path, 0, 0);
897    if (ret < 0)
898        goto out;
899    BUG_ON(ret == 0);
900
901    ret = 0;
902    if (path->slots[0] > 0) {
903        path->slots[0]--;
904        btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
905        if (key.objectid == root->root_key.objectid &&
906            key.type == BTRFS_ROOT_REF_KEY)
907            ret = -ENOTEMPTY;
908    }
909out:
910    btrfs_free_path(path);
911    return ret;
912}
913
914static noinline int key_in_sk(struct btrfs_key *key,
915                  struct btrfs_ioctl_search_key *sk)
916{
917    struct btrfs_key test;
918    int ret;
919
920    test.objectid = sk->min_objectid;
921    test.type = sk->min_type;
922    test.offset = sk->min_offset;
923
924    ret = btrfs_comp_cpu_keys(key, &test);
925    if (ret < 0)
926        return 0;
927
928    test.objectid = sk->max_objectid;
929    test.type = sk->max_type;
930    test.offset = sk->max_offset;
931
932    ret = btrfs_comp_cpu_keys(key, &test);
933    if (ret > 0)
934        return 0;
935    return 1;
936}
937
938static noinline int copy_to_sk(struct btrfs_root *root,
939                   struct btrfs_path *path,
940                   struct btrfs_key *key,
941                   struct btrfs_ioctl_search_key *sk,
942                   char *buf,
943                   unsigned long *sk_offset,
944                   int *num_found)
945{
946    u64 found_transid;
947    struct extent_buffer *leaf;
948    struct btrfs_ioctl_search_header sh;
949    unsigned long item_off;
950    unsigned long item_len;
951    int nritems;
952    int i;
953    int slot;
954    int found = 0;
955    int ret = 0;
956
957    leaf = path->nodes[0];
958    slot = path->slots[0];
959    nritems = btrfs_header_nritems(leaf);
960
961    if (btrfs_header_generation(leaf) > sk->max_transid) {
962        i = nritems;
963        goto advance_key;
964    }
965    found_transid = btrfs_header_generation(leaf);
966
967    for (i = slot; i < nritems; i++) {
968        item_off = btrfs_item_ptr_offset(leaf, i);
969        item_len = btrfs_item_size_nr(leaf, i);
970
971        if (item_len > BTRFS_SEARCH_ARGS_BUFSIZE)
972            item_len = 0;
973
974        if (sizeof(sh) + item_len + *sk_offset >
975            BTRFS_SEARCH_ARGS_BUFSIZE) {
976            ret = 1;
977            goto overflow;
978        }
979
980        btrfs_item_key_to_cpu(leaf, key, i);
981        if (!key_in_sk(key, sk))
982            continue;
983
984        sh.objectid = key->objectid;
985        sh.offset = key->offset;
986        sh.type = key->type;
987        sh.len = item_len;
988        sh.transid = found_transid;
989
990        /* copy search result header */
991        memcpy(buf + *sk_offset, &sh, sizeof(sh));
992        *sk_offset += sizeof(sh);
993
994        if (item_len) {
995            char *p = buf + *sk_offset;
996            /* copy the item */
997            read_extent_buffer(leaf, p,
998                       item_off, item_len);
999            *sk_offset += item_len;
1000        }
1001        found++;
1002
1003        if (*num_found >= sk->nr_items)
1004            break;
1005    }
1006advance_key:
1007    ret = 0;
1008    if (key->offset < (u64)-1 && key->offset < sk->max_offset)
1009        key->offset++;
1010    else if (key->type < (u8)-1 && key->type < sk->max_type) {
1011        key->offset = 0;
1012        key->type++;
1013    } else if (key->objectid < (u64)-1 && key->objectid < sk->max_objectid) {
1014        key->offset = 0;
1015        key->type = 0;
1016        key->objectid++;
1017    } else
1018        ret = 1;
1019overflow:
1020    *num_found += found;
1021    return ret;
1022}
1023
1024static noinline int search_ioctl(struct inode *inode,
1025                 struct btrfs_ioctl_search_args *args)
1026{
1027    struct btrfs_root *root;
1028    struct btrfs_key key;
1029    struct btrfs_key max_key;
1030    struct btrfs_path *path;
1031    struct btrfs_ioctl_search_key *sk = &args->key;
1032    struct btrfs_fs_info *info = BTRFS_I(inode)->root->fs_info;
1033    int ret;
1034    int num_found = 0;
1035    unsigned long sk_offset = 0;
1036
1037    path = btrfs_alloc_path();
1038    if (!path)
1039        return -ENOMEM;
1040
1041    if (sk->tree_id == 0) {
1042        /* search the root of the inode that was passed */
1043        root = BTRFS_I(inode)->root;
1044    } else {
1045        key.objectid = sk->tree_id;
1046        key.type = BTRFS_ROOT_ITEM_KEY;
1047        key.offset = (u64)-1;
1048        root = btrfs_read_fs_root_no_name(info, &key);
1049        if (IS_ERR(root)) {
1050            printk(KERN_ERR "could not find root %llu\n",
1051                   sk->tree_id);
1052            btrfs_free_path(path);
1053            return -ENOENT;
1054        }
1055    }
1056
1057    key.objectid = sk->min_objectid;
1058    key.type = sk->min_type;
1059    key.offset = sk->min_offset;
1060
1061    max_key.objectid = sk->max_objectid;
1062    max_key.type = sk->max_type;
1063    max_key.offset = sk->max_offset;
1064
1065    path->keep_locks = 1;
1066
1067    while(1) {
1068        ret = btrfs_search_forward(root, &key, &max_key, path, 0,
1069                       sk->min_transid);
1070        if (ret != 0) {
1071            if (ret > 0)
1072                ret = 0;
1073            goto err;
1074        }
1075        ret = copy_to_sk(root, path, &key, sk, args->buf,
1076                 &sk_offset, &num_found);
1077        btrfs_release_path(root, path);
1078        if (ret || num_found >= sk->nr_items)
1079            break;
1080
1081    }
1082    ret = 0;
1083err:
1084    sk->nr_items = num_found;
1085    btrfs_free_path(path);
1086    return ret;
1087}
1088
1089static noinline int btrfs_ioctl_tree_search(struct file *file,
1090                       void __user *argp)
1091{
1092     struct btrfs_ioctl_search_args *args;
1093     struct inode *inode;
1094     int ret;
1095
1096    if (!capable(CAP_SYS_ADMIN))
1097        return -EPERM;
1098
1099    args = kmalloc(sizeof(*args), GFP_KERNEL);
1100    if (!args)
1101        return -ENOMEM;
1102
1103    if (copy_from_user(args, argp, sizeof(*args))) {
1104        kfree(args);
1105        return -EFAULT;
1106    }
1107    inode = fdentry(file)->d_inode;
1108    ret = search_ioctl(inode, args);
1109    if (ret == 0 && copy_to_user(argp, args, sizeof(*args)))
1110        ret = -EFAULT;
1111    kfree(args);
1112    return ret;
1113}
1114
1115/*
1116 * Search INODE_REFs to identify path name of 'dirid' directory
1117 * in a 'tree_id' tree. and sets path name to 'name'.
1118 */
1119static noinline int btrfs_search_path_in_tree(struct btrfs_fs_info *info,
1120                u64 tree_id, u64 dirid, char *name)
1121{
1122    struct btrfs_root *root;
1123    struct btrfs_key key;
1124    char *ptr;
1125    int ret = -1;
1126    int slot;
1127    int len;
1128    int total_len = 0;
1129    struct btrfs_inode_ref *iref;
1130    struct extent_buffer *l;
1131    struct btrfs_path *path;
1132
1133    if (dirid == BTRFS_FIRST_FREE_OBJECTID) {
1134        name[0]='\0';
1135        return 0;
1136    }
1137
1138    path = btrfs_alloc_path();
1139    if (!path)
1140        return -ENOMEM;
1141
1142    ptr = &name[BTRFS_INO_LOOKUP_PATH_MAX];
1143
1144    key.objectid = tree_id;
1145    key.type = BTRFS_ROOT_ITEM_KEY;
1146    key.offset = (u64)-1;
1147    root = btrfs_read_fs_root_no_name(info, &key);
1148    if (IS_ERR(root)) {
1149        printk(KERN_ERR "could not find root %llu\n", tree_id);
1150        ret = -ENOENT;
1151        goto out;
1152    }
1153
1154    key.objectid = dirid;
1155    key.type = BTRFS_INODE_REF_KEY;
1156    key.offset = (u64)-1;
1157
1158    while(1) {
1159        ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1160        if (ret < 0)
1161            goto out;
1162
1163        l = path->nodes[0];
1164        slot = path->slots[0];
1165        if (ret > 0 && slot > 0)
1166            slot--;
1167        btrfs_item_key_to_cpu(l, &key, slot);
1168
1169        if (ret > 0 && (key.objectid != dirid ||
1170                key.type != BTRFS_INODE_REF_KEY)) {
1171            ret = -ENOENT;
1172            goto out;
1173        }
1174
1175        iref = btrfs_item_ptr(l, slot, struct btrfs_inode_ref);
1176        len = btrfs_inode_ref_name_len(l, iref);
1177        ptr -= len + 1;
1178        total_len += len + 1;
1179        if (ptr < name)
1180            goto out;
1181
1182        *(ptr + len) = '/';
1183        read_extent_buffer(l, ptr,(unsigned long)(iref + 1), len);
1184
1185        if (key.offset == BTRFS_FIRST_FREE_OBJECTID)
1186            break;
1187
1188        btrfs_release_path(root, path);
1189        key.objectid = key.offset;
1190        key.offset = (u64)-1;
1191        dirid = key.objectid;
1192
1193    }
1194    if (ptr < name)
1195        goto out;
1196    memcpy(name, ptr, total_len);
1197    name[total_len]='\0';
1198    ret = 0;
1199out:
1200    btrfs_free_path(path);
1201    return ret;
1202}
1203
1204static noinline int btrfs_ioctl_ino_lookup(struct file *file,
1205                       void __user *argp)
1206{
1207     struct btrfs_ioctl_ino_lookup_args *args;
1208     struct inode *inode;
1209     int ret;
1210
1211    if (!capable(CAP_SYS_ADMIN))
1212        return -EPERM;
1213
1214    args = kmalloc(sizeof(*args), GFP_KERNEL);
1215    if (!args)
1216        return -ENOMEM;
1217
1218    if (copy_from_user(args, argp, sizeof(*args))) {
1219        kfree(args);
1220        return -EFAULT;
1221    }
1222    inode = fdentry(file)->d_inode;
1223
1224    if (args->treeid == 0)
1225        args->treeid = BTRFS_I(inode)->root->root_key.objectid;
1226
1227    ret = btrfs_search_path_in_tree(BTRFS_I(inode)->root->fs_info,
1228                    args->treeid, args->objectid,
1229                    args->name);
1230
1231    if (ret == 0 && copy_to_user(argp, args, sizeof(*args)))
1232        ret = -EFAULT;
1233
1234    kfree(args);
1235    return ret;
1236}
1237
1238static noinline int btrfs_ioctl_snap_destroy(struct file *file,
1239                         void __user *arg)
1240{
1241    struct dentry *parent = fdentry(file);
1242    struct dentry *dentry;
1243    struct inode *dir = parent->d_inode;
1244    struct inode *inode;
1245    struct btrfs_root *root = BTRFS_I(dir)->root;
1246    struct btrfs_root *dest = NULL;
1247    struct btrfs_ioctl_vol_args *vol_args;
1248    struct btrfs_trans_handle *trans;
1249    int namelen;
1250    int ret;
1251    int err = 0;
1252
1253    if (!capable(CAP_SYS_ADMIN))
1254        return -EPERM;
1255
1256    vol_args = memdup_user(arg, sizeof(*vol_args));
1257    if (IS_ERR(vol_args))
1258        return PTR_ERR(vol_args);
1259
1260    vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
1261    namelen = strlen(vol_args->name);
1262    if (strchr(vol_args->name, '/') ||
1263        strncmp(vol_args->name, "..", namelen) == 0) {
1264        err = -EINVAL;
1265        goto out;
1266    }
1267
1268    err = mnt_want_write(file->f_path.mnt);
1269    if (err)
1270        goto out;
1271
1272    mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
1273    dentry = lookup_one_len(vol_args->name, parent, namelen);
1274    if (IS_ERR(dentry)) {
1275        err = PTR_ERR(dentry);
1276        goto out_unlock_dir;
1277    }
1278
1279    if (!dentry->d_inode) {
1280        err = -ENOENT;
1281        goto out_dput;
1282    }
1283
1284    inode = dentry->d_inode;
1285    if (inode->i_ino != BTRFS_FIRST_FREE_OBJECTID) {
1286        err = -EINVAL;
1287        goto out_dput;
1288    }
1289
1290    dest = BTRFS_I(inode)->root;
1291
1292    mutex_lock(&inode->i_mutex);
1293    err = d_invalidate(dentry);
1294    if (err)
1295        goto out_unlock;
1296
1297    down_write(&root->fs_info->subvol_sem);
1298
1299    err = may_destroy_subvol(dest);
1300    if (err)
1301        goto out_up_write;
1302
1303    trans = btrfs_start_transaction(root, 1);
1304    ret = btrfs_unlink_subvol(trans, root, dir,
1305                dest->root_key.objectid,
1306                dentry->d_name.name,
1307                dentry->d_name.len);
1308    BUG_ON(ret);
1309
1310    btrfs_record_root_in_trans(trans, dest);
1311
1312    memset(&dest->root_item.drop_progress, 0,
1313        sizeof(dest->root_item.drop_progress));
1314    dest->root_item.drop_level = 0;
1315    btrfs_set_root_refs(&dest->root_item, 0);
1316
1317    ret = btrfs_insert_orphan_item(trans,
1318                root->fs_info->tree_root,
1319                dest->root_key.objectid);
1320    BUG_ON(ret);
1321
1322    ret = btrfs_commit_transaction(trans, root);
1323    BUG_ON(ret);
1324    inode->i_flags |= S_DEAD;
1325out_up_write:
1326    up_write(&root->fs_info->subvol_sem);
1327out_unlock:
1328    mutex_unlock(&inode->i_mutex);
1329    if (!err) {
1330        shrink_dcache_sb(root->fs_info->sb);
1331        btrfs_invalidate_inodes(dest);
1332        d_delete(dentry);
1333    }
1334out_dput:
1335    dput(dentry);
1336out_unlock_dir:
1337    mutex_unlock(&dir->i_mutex);
1338    mnt_drop_write(file->f_path.mnt);
1339out:
1340    kfree(vol_args);
1341    return err;
1342}
1343
1344static int btrfs_ioctl_defrag(struct file *file, void __user *argp)
1345{
1346    struct inode *inode = fdentry(file)->d_inode;
1347    struct btrfs_root *root = BTRFS_I(inode)->root;
1348    struct btrfs_ioctl_defrag_range_args *range;
1349    int ret;
1350
1351    ret = mnt_want_write(file->f_path.mnt);
1352    if (ret)
1353        return ret;
1354
1355    switch (inode->i_mode & S_IFMT) {
1356    case S_IFDIR:
1357        if (!capable(CAP_SYS_ADMIN)) {
1358            ret = -EPERM;
1359            goto out;
1360        }
1361        btrfs_defrag_root(root, 0);
1362        btrfs_defrag_root(root->fs_info->extent_root, 0);
1363        break;
1364    case S_IFREG:
1365        if (!(file->f_mode & FMODE_WRITE)) {
1366            ret = -EINVAL;
1367            goto out;
1368        }
1369
1370        range = kzalloc(sizeof(*range), GFP_KERNEL);
1371        if (!range) {
1372            ret = -ENOMEM;
1373            goto out;
1374        }
1375
1376        if (argp) {
1377            if (copy_from_user(range, argp,
1378                       sizeof(*range))) {
1379                ret = -EFAULT;
1380                kfree(range);
1381                goto out;
1382            }
1383            /* compression requires us to start the IO */
1384            if ((range->flags & BTRFS_DEFRAG_RANGE_COMPRESS)) {
1385                range->flags |= BTRFS_DEFRAG_RANGE_START_IO;
1386                range->extent_thresh = (u32)-1;
1387            }
1388        } else {
1389            /* the rest are all set to zero by kzalloc */
1390            range->len = (u64)-1;
1391        }
1392        btrfs_defrag_file(file, range);
1393        kfree(range);
1394        break;
1395    }
1396out:
1397    mnt_drop_write(file->f_path.mnt);
1398    return ret;
1399}
1400
1401static long btrfs_ioctl_add_dev(struct btrfs_root *root, void __user *arg)
1402{
1403    struct btrfs_ioctl_vol_args *vol_args;
1404    int ret;
1405
1406    if (!capable(CAP_SYS_ADMIN))
1407        return -EPERM;
1408
1409    vol_args = memdup_user(arg, sizeof(*vol_args));
1410    if (IS_ERR(vol_args))
1411        return PTR_ERR(vol_args);
1412
1413    vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
1414    ret = btrfs_init_new_device(root, vol_args->name);
1415
1416    kfree(vol_args);
1417    return ret;
1418}
1419
1420static long btrfs_ioctl_rm_dev(struct btrfs_root *root, void __user *arg)
1421{
1422    struct btrfs_ioctl_vol_args *vol_args;
1423    int ret;
1424
1425    if (!capable(CAP_SYS_ADMIN))
1426        return -EPERM;
1427
1428    if (root->fs_info->sb->s_flags & MS_RDONLY)
1429        return -EROFS;
1430
1431    vol_args = memdup_user(arg, sizeof(*vol_args));
1432    if (IS_ERR(vol_args))
1433        return PTR_ERR(vol_args);
1434
1435    vol_args->name[BTRFS_PATH_NAME_MAX] = '\0';
1436    ret = btrfs_rm_device(root, vol_args->name);
1437
1438    kfree(vol_args);
1439    return ret;
1440}
1441
1442static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd,
1443                       u64 off, u64 olen, u64 destoff)
1444{
1445    struct inode *inode = fdentry(file)->d_inode;
1446    struct btrfs_root *root = BTRFS_I(inode)->root;
1447    struct file *src_file;
1448    struct inode *src;
1449    struct btrfs_trans_handle *trans;
1450    struct btrfs_path *path;
1451    struct extent_buffer *leaf;
1452    char *buf;
1453    struct btrfs_key key;
1454    u32 nritems;
1455    int slot;
1456    int ret;
1457    u64 len = olen;
1458    u64 bs = root->fs_info->sb->s_blocksize;
1459    u64 hint_byte;
1460
1461    /*
1462     * TODO:
1463     * - split compressed inline extents. annoying: we need to
1464     * decompress into destination's address_space (the file offset
1465     * may change, so source mapping won't do), then recompress (or
1466     * otherwise reinsert) a subrange.
1467     * - allow ranges within the same file to be cloned (provided
1468     * they don't overlap)?
1469     */
1470
1471    /* the destination must be opened for writing */
1472    if (!(file->f_mode & FMODE_WRITE))
1473        return -EINVAL;
1474
1475    ret = mnt_want_write(file->f_path.mnt);
1476    if (ret)
1477        return ret;
1478
1479    src_file = fget(srcfd);
1480    if (!src_file) {
1481        ret = -EBADF;
1482        goto out_drop_write;
1483    }
1484    src = src_file->f_dentry->d_inode;
1485
1486    ret = -EINVAL;
1487    if (src == inode)
1488        goto out_fput;
1489
1490    ret = -EISDIR;
1491    if (S_ISDIR(src->i_mode) || S_ISDIR(inode->i_mode))
1492        goto out_fput;
1493
1494    ret = -EXDEV;
1495    if (src->i_sb != inode->i_sb || BTRFS_I(src)->root != root)
1496        goto out_fput;
1497
1498    ret = -ENOMEM;
1499    buf = vmalloc(btrfs_level_size(root, 0));
1500    if (!buf)
1501        goto out_fput;
1502
1503    path = btrfs_alloc_path();
1504    if (!path) {
1505        vfree(buf);
1506        goto out_fput;
1507    }
1508    path->reada = 2;
1509
1510    if (inode < src) {
1511        mutex_lock(&inode->i_mutex);
1512        mutex_lock(&src->i_mutex);
1513    } else {
1514        mutex_lock(&src->i_mutex);
1515        mutex_lock(&inode->i_mutex);
1516    }
1517
1518    /* determine range to clone */
1519    ret = -EINVAL;
1520    if (off >= src->i_size || off + len > src->i_size)
1521        goto out_unlock;
1522    if (len == 0)
1523        olen = len = src->i_size - off;
1524    /* if we extend to eof, continue to block boundary */
1525    if (off + len == src->i_size)
1526        len = ((src->i_size + bs-1) & ~(bs-1))
1527            - off;
1528
1529    /* verify the end result is block aligned */
1530    if ((off & (bs-1)) ||
1531        ((off + len) & (bs-1)))
1532        goto out_unlock;
1533
1534    /* do any pending delalloc/csum calc on src, one way or
1535       another, and lock file content */
1536    while (1) {
1537        struct btrfs_ordered_extent *ordered;
1538        lock_extent(&BTRFS_I(src)->io_tree, off, off+len, GFP_NOFS);
1539        ordered = btrfs_lookup_first_ordered_extent(inode, off+len);
1540        if (BTRFS_I(src)->delalloc_bytes == 0 && !ordered)
1541            break;
1542        unlock_extent(&BTRFS_I(src)->io_tree, off, off+len, GFP_NOFS);
1543        if (ordered)
1544            btrfs_put_ordered_extent(ordered);
1545        btrfs_wait_ordered_range(src, off, off+len);
1546    }
1547
1548    trans = btrfs_start_transaction(root, 1);
1549    BUG_ON(!trans);
1550
1551    /* punch hole in destination first */
1552    btrfs_drop_extents(trans, inode, off, off + len, &hint_byte, 1);
1553
1554    /* clone data */
1555    key.objectid = src->i_ino;
1556    key.type = BTRFS_EXTENT_DATA_KEY;
1557    key.offset = 0;
1558
1559    while (1) {
1560        /*
1561         * note the key will change type as we walk through the
1562         * tree.
1563         */
1564        ret = btrfs_search_slot(trans, root, &key, path, 0, 0);
1565        if (ret < 0)
1566            goto out;
1567
1568        nritems = btrfs_header_nritems(path->nodes[0]);
1569        if (path->slots[0] >= nritems) {
1570            ret = btrfs_next_leaf(root, path);
1571            if (ret < 0)
1572                goto out;
1573            if (ret > 0)
1574                break;
1575            nritems = btrfs_header_nritems(path->nodes[0]);
1576        }
1577        leaf = path->nodes[0];
1578        slot = path->slots[0];
1579
1580        btrfs_item_key_to_cpu(leaf, &key, slot);
1581        if (btrfs_key_type(&key) > BTRFS_EXTENT_DATA_KEY ||
1582            key.objectid != src->i_ino)
1583            break;
1584
1585        if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) {
1586            struct btrfs_file_extent_item *extent;
1587            int type;
1588            u32 size;
1589            struct btrfs_key new_key;
1590            u64 disko = 0, diskl = 0;
1591            u64 datao = 0, datal = 0;
1592            u8 comp;
1593
1594            size = btrfs_item_size_nr(leaf, slot);
1595            read_extent_buffer(leaf, buf,
1596                       btrfs_item_ptr_offset(leaf, slot),
1597                       size);
1598
1599            extent = btrfs_item_ptr(leaf, slot,
1600                        struct btrfs_file_extent_item);
1601            comp = btrfs_file_extent_compression(leaf, extent);
1602            type = btrfs_file_extent_type(leaf, extent);
1603            if (type == BTRFS_FILE_EXTENT_REG ||
1604                type == BTRFS_FILE_EXTENT_PREALLOC) {
1605                disko = btrfs_file_extent_disk_bytenr(leaf,
1606                                      extent);
1607                diskl = btrfs_file_extent_disk_num_bytes(leaf,
1608                                 extent);
1609                datao = btrfs_file_extent_offset(leaf, extent);
1610                datal = btrfs_file_extent_num_bytes(leaf,
1611                                    extent);
1612            } else if (type == BTRFS_FILE_EXTENT_INLINE) {
1613                /* take upper bound, may be compressed */
1614                datal = btrfs_file_extent_ram_bytes(leaf,
1615                                    extent);
1616            }
1617            btrfs_release_path(root, path);
1618
1619            if (key.offset + datal < off ||
1620                key.offset >= off+len)
1621                goto next;
1622
1623            memcpy(&new_key, &key, sizeof(new_key));
1624            new_key.objectid = inode->i_ino;
1625            new_key.offset = key.offset + destoff - off;
1626
1627            if (type == BTRFS_FILE_EXTENT_REG ||
1628                type == BTRFS_FILE_EXTENT_PREALLOC) {
1629                ret = btrfs_insert_empty_item(trans, root, path,
1630                                  &new_key, size);
1631                if (ret)
1632                    goto out;
1633
1634                leaf = path->nodes[0];
1635                slot = path->slots[0];
1636                write_extent_buffer(leaf, buf,
1637                        btrfs_item_ptr_offset(leaf, slot),
1638                        size);
1639
1640                extent = btrfs_item_ptr(leaf, slot,
1641                        struct btrfs_file_extent_item);
1642
1643                if (off > key.offset) {
1644                    datao += off - key.offset;
1645                    datal -= off - key.offset;
1646                }
1647
1648                if (key.offset + datal > off + len)
1649                    datal = off + len - key.offset;
1650
1651                /* disko == 0 means it's a hole */
1652                if (!disko)
1653                    datao = 0;
1654
1655                btrfs_set_file_extent_offset(leaf, extent,
1656                                 datao);
1657                btrfs_set_file_extent_num_bytes(leaf, extent,
1658                                datal);
1659                if (disko) {
1660                    inode_add_bytes(inode, datal);
1661                    ret = btrfs_inc_extent_ref(trans, root,
1662                            disko, diskl, 0,
1663                            root->root_key.objectid,
1664                            inode->i_ino,
1665                            new_key.offset - datao);
1666                    BUG_ON(ret);
1667                }
1668            } else if (type == BTRFS_FILE_EXTENT_INLINE) {
1669                u64 skip = 0;
1670                u64 trim = 0;
1671                if (off > key.offset) {
1672                    skip = off - key.offset;
1673                    new_key.offset += skip;
1674                }
1675
1676                if (key.offset + datal > off+len)
1677                    trim = key.offset + datal - (off+len);
1678
1679                if (comp && (skip || trim)) {
1680                    ret = -EINVAL;
1681                    goto out;
1682                }
1683                size -= skip + trim;
1684                datal -= skip + trim;
1685                ret = btrfs_insert_empty_item(trans, root, path,
1686                                  &new_key, size);
1687                if (ret)
1688                    goto out;
1689
1690                if (skip) {
1691                    u32 start =
1692                      btrfs_file_extent_calc_inline_size(0);
1693                    memmove(buf+start, buf+start+skip,
1694                        datal);
1695                }
1696
1697                leaf = path->nodes[0];
1698                slot = path->slots[0];
1699                write_extent_buffer(leaf, buf,
1700                        btrfs_item_ptr_offset(leaf, slot),
1701                        size);
1702                inode_add_bytes(inode, datal);
1703            }
1704
1705            btrfs_mark_buffer_dirty(leaf);
1706        }
1707
1708next:
1709        btrfs_release_path(root, path);
1710        key.offset++;
1711    }
1712    ret = 0;
1713out:
1714    btrfs_release_path(root, path);
1715    if (ret == 0) {
1716        inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1717        if (destoff + olen > inode->i_size)
1718            btrfs_i_size_write(inode, destoff + olen);
1719        BTRFS_I(inode)->flags = BTRFS_I(src)->flags;
1720        ret = btrfs_update_inode(trans, root, inode);
1721    }
1722    btrfs_end_transaction(trans, root);
1723    unlock_extent(&BTRFS_I(src)->io_tree, off, off+len, GFP_NOFS);
1724    if (ret)
1725        vmtruncate(inode, 0);
1726out_unlock:
1727    mutex_unlock(&src->i_mutex);
1728    mutex_unlock(&inode->i_mutex);
1729    vfree(buf);
1730    btrfs_free_path(path);
1731out_fput:
1732    fput(src_file);
1733out_drop_write:
1734    mnt_drop_write(file->f_path.mnt);
1735    return ret;
1736}
1737
1738static long btrfs_ioctl_clone_range(struct file *file, void __user *argp)
1739{
1740    struct btrfs_ioctl_clone_range_args args;
1741
1742    if (copy_from_user(&args, argp, sizeof(args)))
1743        return -EFAULT;
1744    return btrfs_ioctl_clone(file, args.src_fd, args.src_offset,
1745                 args.src_length, args.dest_offset);
1746}
1747
1748/*
1749 * there are many ways the trans_start and trans_end ioctls can lead
1750 * to deadlocks. They should only be used by applications that
1751 * basically own the machine, and have a very in depth understanding
1752 * of all the possible deadlocks and enospc problems.
1753 */
1754static long btrfs_ioctl_trans_start(struct file *file)
1755{
1756    struct inode *inode = fdentry(file)->d_inode;
1757    struct btrfs_root *root = BTRFS_I(inode)->root;
1758    struct btrfs_trans_handle *trans;
1759    int ret;
1760
1761    ret = -EPERM;
1762    if (!capable(CAP_SYS_ADMIN))
1763        goto out;
1764
1765    ret = -EINPROGRESS;
1766    if (file->private_data)
1767        goto out;
1768
1769    ret = mnt_want_write(file->f_path.mnt);
1770    if (ret)
1771        goto out;
1772
1773    mutex_lock(&root->fs_info->trans_mutex);
1774    root->fs_info->open_ioctl_trans++;
1775    mutex_unlock(&root->fs_info->trans_mutex);
1776
1777    ret = -ENOMEM;
1778    trans = btrfs_start_ioctl_transaction(root, 0);
1779    if (!trans)
1780        goto out_drop;
1781
1782    file->private_data = trans;
1783    return 0;
1784
1785out_drop:
1786    mutex_lock(&root->fs_info->trans_mutex);
1787    root->fs_info->open_ioctl_trans--;
1788    mutex_unlock(&root->fs_info->trans_mutex);
1789    mnt_drop_write(file->f_path.mnt);
1790out:
1791    return ret;
1792}
1793
1794static long btrfs_ioctl_default_subvol(struct file *file, void __user *argp)
1795{
1796    struct inode *inode = fdentry(file)->d_inode;
1797    struct btrfs_root *root = BTRFS_I(inode)->root;
1798    struct btrfs_root *new_root;
1799    struct btrfs_dir_item *di;
1800    struct btrfs_trans_handle *trans;
1801    struct btrfs_path *path;
1802    struct btrfs_key location;
1803    struct btrfs_disk_key disk_key;
1804    struct btrfs_super_block *disk_super;
1805    u64 features;
1806    u64 objectid = 0;
1807    u64 dir_id;
1808
1809    if (!capable(CAP_SYS_ADMIN))
1810        return -EPERM;
1811
1812    if (copy_from_user(&objectid, argp, sizeof(objectid)))
1813        return -EFAULT;
1814
1815    if (!objectid)
1816        objectid = root->root_key.objectid;
1817
1818    location.objectid = objectid;
1819    location.type = BTRFS_ROOT_ITEM_KEY;
1820    location.offset = (u64)-1;
1821
1822    new_root = btrfs_read_fs_root_no_name(root->fs_info, &location);
1823    if (IS_ERR(new_root))
1824        return PTR_ERR(new_root);
1825
1826    if (btrfs_root_refs(&new_root->root_item) == 0)
1827        return -ENOENT;
1828
1829    path = btrfs_alloc_path();
1830    if (!path)
1831        return -ENOMEM;
1832    path->leave_spinning = 1;
1833
1834    trans = btrfs_start_transaction(root, 1);
1835    if (!trans) {
1836        btrfs_free_path(path);
1837        return -ENOMEM;
1838    }
1839
1840    dir_id = btrfs_super_root_dir(&root->fs_info->super_copy);
1841    di = btrfs_lookup_dir_item(trans, root->fs_info->tree_root, path,
1842                   dir_id, "default", 7, 1);
1843    if (!di) {
1844        btrfs_free_path(path);
1845        btrfs_end_transaction(trans, root);
1846        printk(KERN_ERR "Umm, you don't have the default dir item, "
1847               "this isn't going to work\n");
1848        return -ENOENT;
1849    }
1850
1851    btrfs_cpu_key_to_disk(&disk_key, &new_root->root_key);
1852    btrfs_set_dir_item_key(path->nodes[0], di, &disk_key);
1853    btrfs_mark_buffer_dirty(path->nodes[0]);
1854    btrfs_free_path(path);
1855
1856    disk_super = &root->fs_info->super_copy;
1857    features = btrfs_super_incompat_flags(disk_super);
1858    if (!(features & BTRFS_FEATURE_INCOMPAT_DEFAULT_SUBVOL)) {
1859        features |= BTRFS_FEATURE_INCOMPAT_DEFAULT_SUBVOL;
1860        btrfs_set_super_incompat_flags(disk_super, features);
1861    }
1862    btrfs_end_transaction(trans, root);
1863
1864    return 0;
1865}
1866
1867long btrfs_ioctl_space_info(struct btrfs_root *root, void __user *arg)
1868{
1869    struct btrfs_ioctl_space_args space_args;
1870    struct btrfs_ioctl_space_info space;
1871    struct btrfs_ioctl_space_info *dest;
1872    struct btrfs_ioctl_space_info *dest_orig;
1873    struct btrfs_ioctl_space_info *user_dest;
1874    struct btrfs_space_info *info;
1875    int alloc_size;
1876    int ret = 0;
1877    int slot_count = 0;
1878
1879    if (copy_from_user(&space_args,
1880               (struct btrfs_ioctl_space_args __user *)arg,
1881               sizeof(space_args)))
1882        return -EFAULT;
1883
1884    /* first we count slots */
1885    rcu_read_lock();
1886    list_for_each_entry_rcu(info, &root->fs_info->space_info, list)
1887        slot_count++;
1888    rcu_read_unlock();
1889
1890    /* space_slots == 0 means they are asking for a count */
1891    if (space_args.space_slots == 0) {
1892        space_args.total_spaces = slot_count;
1893        goto out;
1894    }
1895    alloc_size = sizeof(*dest) * slot_count;
1896    /* we generally have at most 6 or so space infos, one for each raid
1897     * level. So, a whole page should be more than enough for everyone
1898     */
1899    if (alloc_size > PAGE_CACHE_SIZE)
1900        return -ENOMEM;
1901
1902    space_args.total_spaces = 0;
1903    dest = kmalloc(alloc_size, GFP_NOFS);
1904    if (!dest)
1905        return -ENOMEM;
1906    dest_orig = dest;
1907
1908    /* now we have a buffer to copy into */
1909    rcu_read_lock();
1910    list_for_each_entry_rcu(info, &root->fs_info->space_info, list) {
1911        /* make sure we don't copy more than we allocated
1912         * in our buffer
1913         */
1914        if (slot_count == 0)
1915            break;
1916        slot_count--;
1917
1918        /* make sure userland has enough room in their buffer */
1919        if (space_args.total_spaces >= space_args.space_slots)
1920            break;
1921
1922        space.flags = info->flags;
1923        space.total_bytes = info->total_bytes;
1924        space.used_bytes = info->bytes_used;
1925        memcpy(dest, &space, sizeof(space));
1926        dest++;
1927        space_args.total_spaces++;
1928    }
1929    rcu_read_unlock();
1930
1931    user_dest = (struct btrfs_ioctl_space_info *)
1932        (arg + sizeof(struct btrfs_ioctl_space_args));
1933
1934    if (copy_to_user(user_dest, dest_orig, alloc_size))
1935        ret = -EFAULT;
1936
1937    kfree(dest_orig);
1938out:
1939    if (ret == 0 && copy_to_user(arg, &space_args, sizeof(space_args)))
1940        ret = -EFAULT;
1941
1942    return ret;
1943}
1944
1945/*
1946 * there are many ways the trans_start and trans_end ioctls can lead
1947 * to deadlocks. They should only be used by applications that
1948 * basically own the machine, and have a very in depth understanding
1949 * of all the possible deadlocks and enospc problems.
1950 */
1951long btrfs_ioctl_trans_end(struct file *file)
1952{
1953    struct inode *inode = fdentry(file)->d_inode;
1954    struct btrfs_root *root = BTRFS_I(inode)->root;
1955    struct btrfs_trans_handle *trans;
1956
1957    trans = file->private_data;
1958    if (!trans)
1959        return -EINVAL;
1960    file->private_data = NULL;
1961
1962    btrfs_end_transaction(trans, root);
1963
1964    mutex_lock(&root->fs_info->trans_mutex);
1965    root->fs_info->open_ioctl_trans--;
1966    mutex_unlock(&root->fs_info->trans_mutex);
1967
1968    mnt_drop_write(file->f_path.mnt);
1969    return 0;
1970}
1971
1972long btrfs_ioctl(struct file *file, unsigned int
1973        cmd, unsigned long arg)
1974{
1975    struct btrfs_root *root = BTRFS_I(fdentry(file)->d_inode)->root;
1976    void __user *argp = (void __user *)arg;
1977
1978    switch (cmd) {
1979    case FS_IOC_GETFLAGS:
1980        return btrfs_ioctl_getflags(file, argp);
1981    case FS_IOC_SETFLAGS:
1982        return btrfs_ioctl_setflags(file, argp);
1983    case FS_IOC_GETVERSION:
1984        return btrfs_ioctl_getversion(file, argp);
1985    case BTRFS_IOC_SNAP_CREATE:
1986        return btrfs_ioctl_snap_create(file, argp, 0);
1987    case BTRFS_IOC_SUBVOL_CREATE:
1988        return btrfs_ioctl_snap_create(file, argp, 1);
1989    case BTRFS_IOC_SNAP_DESTROY:
1990        return btrfs_ioctl_snap_destroy(file, argp);
1991    case BTRFS_IOC_DEFAULT_SUBVOL:
1992        return btrfs_ioctl_default_subvol(file, argp);
1993    case BTRFS_IOC_DEFRAG:
1994        return btrfs_ioctl_defrag(file, NULL);
1995    case BTRFS_IOC_DEFRAG_RANGE:
1996        return btrfs_ioctl_defrag(file, argp);
1997    case BTRFS_IOC_RESIZE:
1998        return btrfs_ioctl_resize(root, argp);
1999    case BTRFS_IOC_ADD_DEV:
2000        return btrfs_ioctl_add_dev(root, argp);
2001    case BTRFS_IOC_RM_DEV:
2002        return btrfs_ioctl_rm_dev(root, argp);
2003    case BTRFS_IOC_BALANCE:
2004        return btrfs_balance(root->fs_info->dev_root);
2005    case BTRFS_IOC_CLONE:
2006        return btrfs_ioctl_clone(file, arg, 0, 0, 0);
2007    case BTRFS_IOC_CLONE_RANGE:
2008        return btrfs_ioctl_clone_range(file, argp);
2009    case BTRFS_IOC_TRANS_START:
2010        return btrfs_ioctl_trans_start(file);
2011    case BTRFS_IOC_TRANS_END:
2012        return btrfs_ioctl_trans_end(file);
2013    case BTRFS_IOC_TREE_SEARCH:
2014        return btrfs_ioctl_tree_search(file, argp);
2015    case BTRFS_IOC_INO_LOOKUP:
2016        return btrfs_ioctl_ino_lookup(file, argp);
2017    case BTRFS_IOC_SPACE_INFO:
2018        return btrfs_ioctl_space_info(root, argp);
2019    case BTRFS_IOC_SYNC:
2020        btrfs_sync_fs(file->f_dentry->d_sb, 1);
2021        return 0;
2022    }
2023
2024    return -ENOTTY;
2025}
2026

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