2 * Copyright (C) 2007 Oracle. All rights reserved.
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.
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.
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.
19 #include <linux/blkdev.h>
20 #include <linux/module.h>
21 #include <linux/buffer_head.h>
23 #include <linux/pagemap.h>
24 #include <linux/highmem.h>
25 #include <linux/time.h>
26 #include <linux/init.h>
27 #include <linux/seq_file.h>
28 #include <linux/string.h>
29 #include <linux/backing-dev.h>
30 #include <linux/mount.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/parser.h>
37 #include <linux/ctype.h>
38 #include <linux/namei.h>
39 #include <linux/miscdevice.h>
40 #include <linux/magic.h>
41 #include <linux/slab.h>
42 #include <linux/cleancache.h>
43 #include <linux/mnt_namespace.h>
45 #include "delayed-inode.h"
48 #include "transaction.h"
49 #include "btrfs_inode.h"
51 #include "print-tree.h"
56 #include "compression.h"
58 #define CREATE_TRACE_POINTS
59 #include <trace/events/btrfs.h>
61 static const struct super_operations btrfs_super_ops
;
62 static struct file_system_type btrfs_fs_type
;
64 static const char *btrfs_decode_error(struct btrfs_fs_info
*fs_info
, int errno
,
71 errstr
= "IO failure";
74 errstr
= "Out of memory";
77 errstr
= "Readonly filesystem";
81 if (snprintf(nbuf
, 16, "error %d", -errno
) >= 0)
90 static void __save_error_info(struct btrfs_fs_info
*fs_info
)
93 * today we only save the error info into ram. Long term we'll
94 * also send it down to the disk
96 fs_info
->fs_state
= BTRFS_SUPER_FLAG_ERROR
;
100 * We move write_super stuff at umount in order to avoid deadlock
101 * for umount hold all lock.
103 static void save_error_info(struct btrfs_fs_info
*fs_info
)
105 __save_error_info(fs_info
);
108 /* btrfs handle error by forcing the filesystem readonly */
109 static void btrfs_handle_error(struct btrfs_fs_info
*fs_info
)
111 struct super_block
*sb
= fs_info
->sb
;
113 if (sb
->s_flags
& MS_RDONLY
)
116 if (fs_info
->fs_state
& BTRFS_SUPER_FLAG_ERROR
) {
117 sb
->s_flags
|= MS_RDONLY
;
118 printk(KERN_INFO
"btrfs is forced readonly\n");
123 * __btrfs_std_error decodes expected errors from the caller and
124 * invokes the approciate error response.
126 void __btrfs_std_error(struct btrfs_fs_info
*fs_info
, const char *function
,
127 unsigned int line
, int errno
)
129 struct super_block
*sb
= fs_info
->sb
;
134 * Special case: if the error is EROFS, and we're already
135 * under MS_RDONLY, then it is safe here.
137 if (errno
== -EROFS
&& (sb
->s_flags
& MS_RDONLY
))
140 errstr
= btrfs_decode_error(fs_info
, errno
, nbuf
);
141 printk(KERN_CRIT
"BTRFS error (device %s) in %s:%d: %s\n",
142 sb
->s_id
, function
, line
, errstr
);
143 save_error_info(fs_info
);
145 btrfs_handle_error(fs_info
);
148 static void btrfs_put_super(struct super_block
*sb
)
150 struct btrfs_root
*root
= btrfs_sb(sb
);
153 ret
= close_ctree(root
);
154 sb
->s_fs_info
= NULL
;
156 (void)ret
; /* FIXME: need to fix VFS to return error? */
160 Opt_degraded
, Opt_subvol
, Opt_subvolid
, Opt_device
, Opt_nodatasum
,
161 Opt_nodatacow
, Opt_max_inline
, Opt_alloc_start
, Opt_nobarrier
, Opt_ssd
,
162 Opt_nossd
, Opt_ssd_spread
, Opt_thread_pool
, Opt_noacl
, Opt_compress
,
163 Opt_compress_type
, Opt_compress_force
, Opt_compress_force_type
,
164 Opt_notreelog
, Opt_ratio
, Opt_flushoncommit
, Opt_discard
,
165 Opt_space_cache
, Opt_clear_cache
, Opt_user_subvol_rm_allowed
,
166 Opt_enospc_debug
, Opt_subvolrootid
, Opt_defrag
,
167 Opt_inode_cache
, Opt_no_space_cache
, Opt_err
,
170 static match_table_t tokens
= {
171 {Opt_degraded
, "degraded"},
172 {Opt_subvol
, "subvol=%s"},
173 {Opt_subvolid
, "subvolid=%d"},
174 {Opt_device
, "device=%s"},
175 {Opt_nodatasum
, "nodatasum"},
176 {Opt_nodatacow
, "nodatacow"},
177 {Opt_nobarrier
, "nobarrier"},
178 {Opt_max_inline
, "max_inline=%s"},
179 {Opt_alloc_start
, "alloc_start=%s"},
180 {Opt_thread_pool
, "thread_pool=%d"},
181 {Opt_compress
, "compress"},
182 {Opt_compress_type
, "compress=%s"},
183 {Opt_compress_force
, "compress-force"},
184 {Opt_compress_force_type
, "compress-force=%s"},
186 {Opt_ssd_spread
, "ssd_spread"},
187 {Opt_nossd
, "nossd"},
188 {Opt_noacl
, "noacl"},
189 {Opt_notreelog
, "notreelog"},
190 {Opt_flushoncommit
, "flushoncommit"},
191 {Opt_ratio
, "metadata_ratio=%d"},
192 {Opt_discard
, "discard"},
193 {Opt_space_cache
, "space_cache"},
194 {Opt_clear_cache
, "clear_cache"},
195 {Opt_user_subvol_rm_allowed
, "user_subvol_rm_allowed"},
196 {Opt_enospc_debug
, "enospc_debug"},
197 {Opt_subvolrootid
, "subvolrootid=%d"},
198 {Opt_defrag
, "autodefrag"},
199 {Opt_inode_cache
, "inode_cache"},
200 {Opt_no_space_cache
, "no_space_cache"},
205 * Regular mount options parser. Everything that is needed only when
206 * reading in a new superblock is parsed here.
208 int btrfs_parse_options(struct btrfs_root
*root
, char *options
)
210 struct btrfs_fs_info
*info
= root
->fs_info
;
211 substring_t args
[MAX_OPT_ARGS
];
212 char *p
, *num
, *orig
= NULL
;
217 bool compress_force
= false;
219 cache_gen
= btrfs_super_cache_generation(&root
->fs_info
->super_copy
);
221 btrfs_set_opt(info
->mount_opt
, SPACE_CACHE
);
227 * strsep changes the string, duplicate it because parse_options
230 options
= kstrdup(options
, GFP_NOFS
);
236 while ((p
= strsep(&options
, ",")) != NULL
) {
241 token
= match_token(p
, tokens
, args
);
244 printk(KERN_INFO
"btrfs: allowing degraded mounts\n");
245 btrfs_set_opt(info
->mount_opt
, DEGRADED
);
249 case Opt_subvolrootid
:
252 * These are parsed by btrfs_parse_early_options
253 * and can be happily ignored here.
257 printk(KERN_INFO
"btrfs: setting nodatasum\n");
258 btrfs_set_opt(info
->mount_opt
, NODATASUM
);
261 printk(KERN_INFO
"btrfs: setting nodatacow\n");
262 btrfs_set_opt(info
->mount_opt
, NODATACOW
);
263 btrfs_set_opt(info
->mount_opt
, NODATASUM
);
265 case Opt_compress_force
:
266 case Opt_compress_force_type
:
267 compress_force
= true;
269 case Opt_compress_type
:
270 if (token
== Opt_compress
||
271 token
== Opt_compress_force
||
272 strcmp(args
[0].from
, "zlib") == 0) {
273 compress_type
= "zlib";
274 info
->compress_type
= BTRFS_COMPRESS_ZLIB
;
275 } else if (strcmp(args
[0].from
, "lzo") == 0) {
276 compress_type
= "lzo";
277 info
->compress_type
= BTRFS_COMPRESS_LZO
;
283 btrfs_set_opt(info
->mount_opt
, COMPRESS
);
284 if (compress_force
) {
285 btrfs_set_opt(info
->mount_opt
, FORCE_COMPRESS
);
286 pr_info("btrfs: force %s compression\n",
289 pr_info("btrfs: use %s compression\n",
293 printk(KERN_INFO
"btrfs: use ssd allocation scheme\n");
294 btrfs_set_opt(info
->mount_opt
, SSD
);
297 printk(KERN_INFO
"btrfs: use spread ssd "
298 "allocation scheme\n");
299 btrfs_set_opt(info
->mount_opt
, SSD
);
300 btrfs_set_opt(info
->mount_opt
, SSD_SPREAD
);
303 printk(KERN_INFO
"btrfs: not using ssd allocation "
305 btrfs_set_opt(info
->mount_opt
, NOSSD
);
306 btrfs_clear_opt(info
->mount_opt
, SSD
);
307 btrfs_clear_opt(info
->mount_opt
, SSD_SPREAD
);
310 printk(KERN_INFO
"btrfs: turning off barriers\n");
311 btrfs_set_opt(info
->mount_opt
, NOBARRIER
);
313 case Opt_thread_pool
:
315 match_int(&args
[0], &intarg
);
317 info
->thread_pool_size
= intarg
;
318 printk(KERN_INFO
"btrfs: thread pool %d\n",
319 info
->thread_pool_size
);
323 num
= match_strdup(&args
[0]);
325 info
->max_inline
= memparse(num
, NULL
);
328 if (info
->max_inline
) {
329 info
->max_inline
= max_t(u64
,
333 printk(KERN_INFO
"btrfs: max_inline at %llu\n",
334 (unsigned long long)info
->max_inline
);
337 case Opt_alloc_start
:
338 num
= match_strdup(&args
[0]);
340 info
->alloc_start
= memparse(num
, NULL
);
343 "btrfs: allocations start at %llu\n",
344 (unsigned long long)info
->alloc_start
);
348 root
->fs_info
->sb
->s_flags
&= ~MS_POSIXACL
;
351 printk(KERN_INFO
"btrfs: disabling tree log\n");
352 btrfs_set_opt(info
->mount_opt
, NOTREELOG
);
354 case Opt_flushoncommit
:
355 printk(KERN_INFO
"btrfs: turning on flush-on-commit\n");
356 btrfs_set_opt(info
->mount_opt
, FLUSHONCOMMIT
);
360 match_int(&args
[0], &intarg
);
362 info
->metadata_ratio
= intarg
;
363 printk(KERN_INFO
"btrfs: metadata ratio %d\n",
364 info
->metadata_ratio
);
368 btrfs_set_opt(info
->mount_opt
, DISCARD
);
370 case Opt_space_cache
:
371 btrfs_set_opt(info
->mount_opt
, SPACE_CACHE
);
373 case Opt_no_space_cache
:
374 printk(KERN_INFO
"btrfs: disabling disk space caching\n");
375 btrfs_clear_opt(info
->mount_opt
, SPACE_CACHE
);
377 case Opt_inode_cache
:
378 printk(KERN_INFO
"btrfs: enabling inode map caching\n");
379 btrfs_set_opt(info
->mount_opt
, INODE_MAP_CACHE
);
381 case Opt_clear_cache
:
382 printk(KERN_INFO
"btrfs: force clearing of disk cache\n");
383 btrfs_set_opt(info
->mount_opt
, CLEAR_CACHE
);
385 case Opt_user_subvol_rm_allowed
:
386 btrfs_set_opt(info
->mount_opt
, USER_SUBVOL_RM_ALLOWED
);
388 case Opt_enospc_debug
:
389 btrfs_set_opt(info
->mount_opt
, ENOSPC_DEBUG
);
392 printk(KERN_INFO
"btrfs: enabling auto defrag");
393 btrfs_set_opt(info
->mount_opt
, AUTO_DEFRAG
);
396 printk(KERN_INFO
"btrfs: unrecognized mount option "
405 if (!ret
&& btrfs_test_opt(root
, SPACE_CACHE
))
406 printk(KERN_INFO
"btrfs: disk space caching is enabled\n");
412 * Parse mount options that are required early in the mount process.
414 * All other options will be parsed on much later in the mount process and
415 * only when we need to allocate a new super block.
417 static int btrfs_parse_early_options(const char *options
, fmode_t flags
,
418 void *holder
, char **subvol_name
, u64
*subvol_objectid
,
419 u64
*subvol_rootid
, struct btrfs_fs_devices
**fs_devices
)
421 substring_t args
[MAX_OPT_ARGS
];
422 char *device_name
, *opts
, *orig
, *p
;
430 * strsep changes the string, duplicate it because parse_options
433 opts
= kstrdup(options
, GFP_KERNEL
);
438 while ((p
= strsep(&opts
, ",")) != NULL
) {
443 token
= match_token(p
, tokens
, args
);
446 *subvol_name
= match_strdup(&args
[0]);
450 error
= match_int(&args
[0], &intarg
);
452 /* we want the original fs_tree */
455 BTRFS_FS_TREE_OBJECTID
;
457 *subvol_objectid
= intarg
;
460 case Opt_subvolrootid
:
462 error
= match_int(&args
[0], &intarg
);
464 /* we want the original fs_tree */
467 BTRFS_FS_TREE_OBJECTID
;
469 *subvol_rootid
= intarg
;
473 device_name
= match_strdup(&args
[0]);
478 error
= btrfs_scan_one_device(device_name
,
479 flags
, holder
, fs_devices
);
494 static struct dentry
*get_default_root(struct super_block
*sb
,
497 struct btrfs_root
*root
= sb
->s_fs_info
;
498 struct btrfs_root
*new_root
;
499 struct btrfs_dir_item
*di
;
500 struct btrfs_path
*path
;
501 struct btrfs_key location
;
507 * We have a specific subvol we want to mount, just setup location and
508 * go look up the root.
510 if (subvol_objectid
) {
511 location
.objectid
= subvol_objectid
;
512 location
.type
= BTRFS_ROOT_ITEM_KEY
;
513 location
.offset
= (u64
)-1;
517 path
= btrfs_alloc_path();
519 return ERR_PTR(-ENOMEM
);
520 path
->leave_spinning
= 1;
523 * Find the "default" dir item which points to the root item that we
524 * will mount by default if we haven't been given a specific subvolume
527 dir_id
= btrfs_super_root_dir(&root
->fs_info
->super_copy
);
528 di
= btrfs_lookup_dir_item(NULL
, root
, path
, dir_id
, "default", 7, 0);
530 btrfs_free_path(path
);
535 * Ok the default dir item isn't there. This is weird since
536 * it's always been there, but don't freak out, just try and
537 * mount to root most subvolume.
539 btrfs_free_path(path
);
540 dir_id
= BTRFS_FIRST_FREE_OBJECTID
;
541 new_root
= root
->fs_info
->fs_root
;
545 btrfs_dir_item_key_to_cpu(path
->nodes
[0], di
, &location
);
546 btrfs_free_path(path
);
549 new_root
= btrfs_read_fs_root_no_name(root
->fs_info
, &location
);
550 if (IS_ERR(new_root
))
551 return ERR_CAST(new_root
);
553 if (btrfs_root_refs(&new_root
->root_item
) == 0)
554 return ERR_PTR(-ENOENT
);
556 dir_id
= btrfs_root_dirid(&new_root
->root_item
);
558 location
.objectid
= dir_id
;
559 location
.type
= BTRFS_INODE_ITEM_KEY
;
562 inode
= btrfs_iget(sb
, &location
, new_root
, &new);
564 return ERR_CAST(inode
);
567 * If we're just mounting the root most subvol put the inode and return
568 * a reference to the dentry. We will have already gotten a reference
569 * to the inode in btrfs_fill_super so we're good to go.
571 if (!new && sb
->s_root
->d_inode
== inode
) {
573 return dget(sb
->s_root
);
576 return d_obtain_alias(inode
);
579 static int btrfs_fill_super(struct super_block
*sb
,
580 struct btrfs_fs_devices
*fs_devices
,
581 void *data
, int silent
)
584 struct dentry
*root_dentry
;
585 struct btrfs_root
*tree_root
;
586 struct btrfs_key key
;
589 sb
->s_maxbytes
= MAX_LFS_FILESIZE
;
590 sb
->s_magic
= BTRFS_SUPER_MAGIC
;
591 sb
->s_op
= &btrfs_super_ops
;
592 sb
->s_d_op
= &btrfs_dentry_operations
;
593 sb
->s_export_op
= &btrfs_export_ops
;
594 sb
->s_xattr
= btrfs_xattr_handlers
;
596 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
597 sb
->s_flags
|= MS_POSIXACL
;
600 tree_root
= open_ctree(sb
, fs_devices
, (char *)data
);
602 if (IS_ERR(tree_root
)) {
603 printk("btrfs: open_ctree failed\n");
604 return PTR_ERR(tree_root
);
606 sb
->s_fs_info
= tree_root
;
608 key
.objectid
= BTRFS_FIRST_FREE_OBJECTID
;
609 key
.type
= BTRFS_INODE_ITEM_KEY
;
611 inode
= btrfs_iget(sb
, &key
, tree_root
->fs_info
->fs_root
, NULL
);
613 err
= PTR_ERR(inode
);
617 root_dentry
= d_alloc_root(inode
);
624 sb
->s_root
= root_dentry
;
626 save_mount_options(sb
, data
);
627 cleancache_init_fs(sb
);
631 close_ctree(tree_root
);
635 int btrfs_sync_fs(struct super_block
*sb
, int wait
)
637 struct btrfs_trans_handle
*trans
;
638 struct btrfs_root
*root
= btrfs_sb(sb
);
641 trace_btrfs_sync_fs(wait
);
644 filemap_flush(root
->fs_info
->btree_inode
->i_mapping
);
648 btrfs_start_delalloc_inodes(root
, 0);
649 btrfs_wait_ordered_extents(root
, 0, 0);
651 trans
= btrfs_start_transaction(root
, 0);
653 return PTR_ERR(trans
);
654 ret
= btrfs_commit_transaction(trans
, root
);
658 static int btrfs_show_options(struct seq_file
*seq
, struct vfsmount
*vfs
)
660 struct btrfs_root
*root
= btrfs_sb(vfs
->mnt_sb
);
661 struct btrfs_fs_info
*info
= root
->fs_info
;
664 if (btrfs_test_opt(root
, DEGRADED
))
665 seq_puts(seq
, ",degraded");
666 if (btrfs_test_opt(root
, NODATASUM
))
667 seq_puts(seq
, ",nodatasum");
668 if (btrfs_test_opt(root
, NODATACOW
))
669 seq_puts(seq
, ",nodatacow");
670 if (btrfs_test_opt(root
, NOBARRIER
))
671 seq_puts(seq
, ",nobarrier");
672 if (info
->max_inline
!= 8192 * 1024)
673 seq_printf(seq
, ",max_inline=%llu",
674 (unsigned long long)info
->max_inline
);
675 if (info
->alloc_start
!= 0)
676 seq_printf(seq
, ",alloc_start=%llu",
677 (unsigned long long)info
->alloc_start
);
678 if (info
->thread_pool_size
!= min_t(unsigned long,
679 num_online_cpus() + 2, 8))
680 seq_printf(seq
, ",thread_pool=%d", info
->thread_pool_size
);
681 if (btrfs_test_opt(root
, COMPRESS
)) {
682 if (info
->compress_type
== BTRFS_COMPRESS_ZLIB
)
683 compress_type
= "zlib";
685 compress_type
= "lzo";
686 if (btrfs_test_opt(root
, FORCE_COMPRESS
))
687 seq_printf(seq
, ",compress-force=%s", compress_type
);
689 seq_printf(seq
, ",compress=%s", compress_type
);
691 if (btrfs_test_opt(root
, NOSSD
))
692 seq_puts(seq
, ",nossd");
693 if (btrfs_test_opt(root
, SSD_SPREAD
))
694 seq_puts(seq
, ",ssd_spread");
695 else if (btrfs_test_opt(root
, SSD
))
696 seq_puts(seq
, ",ssd");
697 if (btrfs_test_opt(root
, NOTREELOG
))
698 seq_puts(seq
, ",notreelog");
699 if (btrfs_test_opt(root
, FLUSHONCOMMIT
))
700 seq_puts(seq
, ",flushoncommit");
701 if (btrfs_test_opt(root
, DISCARD
))
702 seq_puts(seq
, ",discard");
703 if (!(root
->fs_info
->sb
->s_flags
& MS_POSIXACL
))
704 seq_puts(seq
, ",noacl");
705 if (btrfs_test_opt(root
, SPACE_CACHE
))
706 seq_puts(seq
, ",space_cache");
708 seq_puts(seq
, ",no_space_cache");
709 if (btrfs_test_opt(root
, CLEAR_CACHE
))
710 seq_puts(seq
, ",clear_cache");
711 if (btrfs_test_opt(root
, USER_SUBVOL_RM_ALLOWED
))
712 seq_puts(seq
, ",user_subvol_rm_allowed");
713 if (btrfs_test_opt(root
, ENOSPC_DEBUG
))
714 seq_puts(seq
, ",enospc_debug");
715 if (btrfs_test_opt(root
, AUTO_DEFRAG
))
716 seq_puts(seq
, ",autodefrag");
717 if (btrfs_test_opt(root
, INODE_MAP_CACHE
))
718 seq_puts(seq
, ",inode_cache");
722 static int btrfs_test_super(struct super_block
*s
, void *data
)
724 struct btrfs_root
*test_root
= data
;
725 struct btrfs_root
*root
= btrfs_sb(s
);
728 * If this super block is going away, return false as it
729 * can't match as an existing super block.
731 if (!atomic_read(&s
->s_active
))
733 return root
->fs_info
->fs_devices
== test_root
->fs_info
->fs_devices
;
736 static int btrfs_set_super(struct super_block
*s
, void *data
)
740 return set_anon_super(s
, data
);
744 * This will strip out the subvol=%s argument for an argument string and add
745 * subvolid=0 to make sure we get the actual tree root for path walking to the
748 static char *setup_root_args(char *args
)
751 unsigned len
= strlen(args
) + 2;
756 * We need the same args as before, but minus
764 * which is a difference of 2 characters, so we allocate strlen(args) +
767 ret
= kzalloc(len
* sizeof(char), GFP_NOFS
);
770 pos
= strstr(args
, "subvol=");
772 /* This shouldn't happen, but just in case.. */
779 * The subvol=<> arg is not at the front of the string, copy everybody
780 * up to that into ret.
785 copied
+= strlen(args
);
789 strncpy(ret
+ copied
, "subvolid=0", len
- copied
);
791 /* Length of subvolid=0 */
795 * If there is no , after the subvol= option then we know there's no
796 * other options and we can just return.
798 pos
= strchr(pos
, ',');
802 /* Copy the rest of the arguments into our buffer */
803 strncpy(ret
+ copied
, pos
, len
- copied
);
804 copied
+= strlen(pos
);
809 static struct dentry
*mount_subvol(const char *subvol_name
, int flags
,
810 const char *device_name
, char *data
)
812 struct super_block
*s
;
814 struct vfsmount
*mnt
;
815 struct mnt_namespace
*ns_private
;
820 newargs
= setup_root_args(data
);
822 return ERR_PTR(-ENOMEM
);
823 mnt
= vfs_kern_mount(&btrfs_fs_type
, flags
, device_name
,
827 return ERR_CAST(mnt
);
829 ns_private
= create_mnt_ns(mnt
);
830 if (IS_ERR(ns_private
)) {
832 return ERR_CAST(ns_private
);
836 * This will trigger the automount of the subvol so we can just
837 * drop the mnt we have here and return the dentry that we
840 error
= vfs_path_lookup(mnt
->mnt_root
, mnt
, subvol_name
,
841 LOOKUP_FOLLOW
, &path
);
842 put_mnt_ns(ns_private
);
844 return ERR_PTR(error
);
846 /* Get a ref to the sb and the dentry we found and return it */
847 s
= path
.mnt
->mnt_sb
;
848 atomic_inc(&s
->s_active
);
849 root
= dget(path
.dentry
);
851 down_write(&s
->s_umount
);
857 * Find a superblock for the given device / mount point.
859 * Note: This is based on get_sb_bdev from fs/super.c with a few additions
860 * for multiple device setup. Make sure to keep it in sync.
862 static struct dentry
*btrfs_mount(struct file_system_type
*fs_type
, int flags
,
863 const char *device_name
, void *data
)
865 struct block_device
*bdev
= NULL
;
866 struct super_block
*s
;
868 struct btrfs_fs_devices
*fs_devices
= NULL
;
869 struct btrfs_root
*tree_root
= NULL
;
870 struct btrfs_fs_info
*fs_info
= NULL
;
871 fmode_t mode
= FMODE_READ
;
872 char *subvol_name
= NULL
;
873 u64 subvol_objectid
= 0;
874 u64 subvol_rootid
= 0;
877 if (!(flags
& MS_RDONLY
))
880 error
= btrfs_parse_early_options(data
, mode
, fs_type
,
881 &subvol_name
, &subvol_objectid
,
882 &subvol_rootid
, &fs_devices
);
884 return ERR_PTR(error
);
887 root
= mount_subvol(subvol_name
, flags
, device_name
, data
);
892 error
= btrfs_scan_one_device(device_name
, mode
, fs_type
, &fs_devices
);
894 return ERR_PTR(error
);
896 error
= btrfs_open_devices(fs_devices
, mode
, fs_type
);
898 return ERR_PTR(error
);
900 if (!(flags
& MS_RDONLY
) && fs_devices
->rw_devices
== 0) {
902 goto error_close_devices
;
906 * Setup a dummy root and fs_info for test/set super. This is because
907 * we don't actually fill this stuff out until open_ctree, but we need
908 * it for searching for existing supers, so this lets us do that and
909 * then open_ctree will properly initialize everything later.
911 fs_info
= kzalloc(sizeof(struct btrfs_fs_info
), GFP_NOFS
);
912 tree_root
= kzalloc(sizeof(struct btrfs_root
), GFP_NOFS
);
913 if (!fs_info
|| !tree_root
) {
915 goto error_close_devices
;
917 fs_info
->tree_root
= tree_root
;
918 fs_info
->fs_devices
= fs_devices
;
919 tree_root
->fs_info
= fs_info
;
921 bdev
= fs_devices
->latest_bdev
;
922 s
= sget(fs_type
, btrfs_test_super
, btrfs_set_super
, tree_root
);
925 goto error_close_devices
;
929 if ((flags
^ s
->s_flags
) & MS_RDONLY
) {
930 deactivate_locked_super(s
);
931 return ERR_PTR(-EBUSY
);
934 btrfs_close_devices(fs_devices
);
938 char b
[BDEVNAME_SIZE
];
940 s
->s_flags
= flags
| MS_NOSEC
;
941 strlcpy(s
->s_id
, bdevname(bdev
, b
), sizeof(s
->s_id
));
942 error
= btrfs_fill_super(s
, fs_devices
, data
,
943 flags
& MS_SILENT
? 1 : 0);
945 deactivate_locked_super(s
);
946 return ERR_PTR(error
);
949 btrfs_sb(s
)->fs_info
->bdev_holder
= fs_type
;
950 s
->s_flags
|= MS_ACTIVE
;
953 root
= get_default_root(s
, subvol_objectid
);
955 deactivate_locked_super(s
);
962 btrfs_close_devices(fs_devices
);
965 return ERR_PTR(error
);
968 static int btrfs_remount(struct super_block
*sb
, int *flags
, char *data
)
970 struct btrfs_root
*root
= btrfs_sb(sb
);
973 ret
= btrfs_parse_options(root
, data
);
977 if ((*flags
& MS_RDONLY
) == (sb
->s_flags
& MS_RDONLY
))
980 if (*flags
& MS_RDONLY
) {
981 sb
->s_flags
|= MS_RDONLY
;
983 ret
= btrfs_commit_super(root
);
986 if (root
->fs_info
->fs_devices
->rw_devices
== 0)
989 if (btrfs_super_log_root(&root
->fs_info
->super_copy
) != 0)
992 ret
= btrfs_cleanup_fs_roots(root
->fs_info
);
995 /* recover relocation */
996 ret
= btrfs_recover_relocation(root
);
999 sb
->s_flags
&= ~MS_RDONLY
;
1005 /* Used to sort the devices by max_avail(descending sort) */
1006 static int btrfs_cmp_device_free_bytes(const void *dev_info1
,
1007 const void *dev_info2
)
1009 if (((struct btrfs_device_info
*)dev_info1
)->max_avail
>
1010 ((struct btrfs_device_info
*)dev_info2
)->max_avail
)
1012 else if (((struct btrfs_device_info
*)dev_info1
)->max_avail
<
1013 ((struct btrfs_device_info
*)dev_info2
)->max_avail
)
1020 * sort the devices by max_avail, in which max free extent size of each device
1021 * is stored.(Descending Sort)
1023 static inline void btrfs_descending_sort_devices(
1024 struct btrfs_device_info
*devices
,
1027 sort(devices
, nr_devices
, sizeof(struct btrfs_device_info
),
1028 btrfs_cmp_device_free_bytes
, NULL
);
1032 * The helper to calc the free space on the devices that can be used to store
1035 static int btrfs_calc_avail_data_space(struct btrfs_root
*root
, u64
*free_bytes
)
1037 struct btrfs_fs_info
*fs_info
= root
->fs_info
;
1038 struct btrfs_device_info
*devices_info
;
1039 struct btrfs_fs_devices
*fs_devices
= fs_info
->fs_devices
;
1040 struct btrfs_device
*device
;
1045 u64 min_stripe_size
;
1046 int min_stripes
= 1;
1047 int i
= 0, nr_devices
;
1050 nr_devices
= fs_info
->fs_devices
->rw_devices
;
1051 BUG_ON(!nr_devices
);
1053 devices_info
= kmalloc(sizeof(*devices_info
) * nr_devices
,
1058 /* calc min stripe number for data space alloction */
1059 type
= btrfs_get_alloc_profile(root
, 1);
1060 if (type
& BTRFS_BLOCK_GROUP_RAID0
)
1062 else if (type
& BTRFS_BLOCK_GROUP_RAID1
)
1064 else if (type
& BTRFS_BLOCK_GROUP_RAID10
)
1067 if (type
& BTRFS_BLOCK_GROUP_DUP
)
1068 min_stripe_size
= 2 * BTRFS_STRIPE_LEN
;
1070 min_stripe_size
= BTRFS_STRIPE_LEN
;
1072 list_for_each_entry(device
, &fs_devices
->alloc_list
, dev_alloc_list
) {
1073 if (!device
->in_fs_metadata
)
1076 avail_space
= device
->total_bytes
- device
->bytes_used
;
1078 /* align with stripe_len */
1079 do_div(avail_space
, BTRFS_STRIPE_LEN
);
1080 avail_space
*= BTRFS_STRIPE_LEN
;
1083 * In order to avoid overwritting the superblock on the drive,
1084 * btrfs starts at an offset of at least 1MB when doing chunk
1087 skip_space
= 1024 * 1024;
1089 /* user can set the offset in fs_info->alloc_start. */
1090 if (fs_info
->alloc_start
+ BTRFS_STRIPE_LEN
<=
1091 device
->total_bytes
)
1092 skip_space
= max(fs_info
->alloc_start
, skip_space
);
1095 * btrfs can not use the free space in [0, skip_space - 1],
1096 * we must subtract it from the total. In order to implement
1097 * it, we account the used space in this range first.
1099 ret
= btrfs_account_dev_extents_size(device
, 0, skip_space
- 1,
1102 kfree(devices_info
);
1106 /* calc the free space in [0, skip_space - 1] */
1107 skip_space
-= used_space
;
1110 * we can use the free space in [0, skip_space - 1], subtract
1111 * it from the total.
1113 if (avail_space
&& avail_space
>= skip_space
)
1114 avail_space
-= skip_space
;
1118 if (avail_space
< min_stripe_size
)
1121 devices_info
[i
].dev
= device
;
1122 devices_info
[i
].max_avail
= avail_space
;
1129 btrfs_descending_sort_devices(devices_info
, nr_devices
);
1133 while (nr_devices
>= min_stripes
) {
1134 if (devices_info
[i
].max_avail
>= min_stripe_size
) {
1138 avail_space
+= devices_info
[i
].max_avail
* min_stripes
;
1139 alloc_size
= devices_info
[i
].max_avail
;
1140 for (j
= i
+ 1 - min_stripes
; j
<= i
; j
++)
1141 devices_info
[j
].max_avail
-= alloc_size
;
1147 kfree(devices_info
);
1148 *free_bytes
= avail_space
;
1152 static int btrfs_statfs(struct dentry
*dentry
, struct kstatfs
*buf
)
1154 struct btrfs_root
*root
= btrfs_sb(dentry
->d_sb
);
1155 struct btrfs_super_block
*disk_super
= &root
->fs_info
->super_copy
;
1156 struct list_head
*head
= &root
->fs_info
->space_info
;
1157 struct btrfs_space_info
*found
;
1159 u64 total_free_data
= 0;
1160 int bits
= dentry
->d_sb
->s_blocksize_bits
;
1161 __be32
*fsid
= (__be32
*)root
->fs_info
->fsid
;
1164 /* holding chunk_muext to avoid allocating new chunks */
1165 mutex_lock(&root
->fs_info
->chunk_mutex
);
1167 list_for_each_entry_rcu(found
, head
, list
) {
1168 if (found
->flags
& BTRFS_BLOCK_GROUP_DATA
) {
1169 total_free_data
+= found
->disk_total
- found
->disk_used
;
1171 btrfs_account_ro_block_groups_free_space(found
);
1174 total_used
+= found
->disk_used
;
1178 buf
->f_namelen
= BTRFS_NAME_LEN
;
1179 buf
->f_blocks
= btrfs_super_total_bytes(disk_super
) >> bits
;
1180 buf
->f_bfree
= buf
->f_blocks
- (total_used
>> bits
);
1181 buf
->f_bsize
= dentry
->d_sb
->s_blocksize
;
1182 buf
->f_type
= BTRFS_SUPER_MAGIC
;
1183 buf
->f_bavail
= total_free_data
;
1184 ret
= btrfs_calc_avail_data_space(root
, &total_free_data
);
1186 mutex_unlock(&root
->fs_info
->chunk_mutex
);
1189 buf
->f_bavail
+= total_free_data
;
1190 buf
->f_bavail
= buf
->f_bavail
>> bits
;
1191 mutex_unlock(&root
->fs_info
->chunk_mutex
);
1193 /* We treat it as constant endianness (it doesn't matter _which_)
1194 because we want the fsid to come out the same whether mounted
1195 on a big-endian or little-endian host */
1196 buf
->f_fsid
.val
[0] = be32_to_cpu(fsid
[0]) ^ be32_to_cpu(fsid
[2]);
1197 buf
->f_fsid
.val
[1] = be32_to_cpu(fsid
[1]) ^ be32_to_cpu(fsid
[3]);
1198 /* Mask in the root object ID too, to disambiguate subvols */
1199 buf
->f_fsid
.val
[0] ^= BTRFS_I(dentry
->d_inode
)->root
->objectid
>> 32;
1200 buf
->f_fsid
.val
[1] ^= BTRFS_I(dentry
->d_inode
)->root
->objectid
;
1205 static struct file_system_type btrfs_fs_type
= {
1206 .owner
= THIS_MODULE
,
1208 .mount
= btrfs_mount
,
1209 .kill_sb
= kill_anon_super
,
1210 .fs_flags
= FS_REQUIRES_DEV
,
1214 * used by btrfsctl to scan devices when no FS is mounted
1216 static long btrfs_control_ioctl(struct file
*file
, unsigned int cmd
,
1219 struct btrfs_ioctl_vol_args
*vol
;
1220 struct btrfs_fs_devices
*fs_devices
;
1223 if (!capable(CAP_SYS_ADMIN
))
1226 vol
= memdup_user((void __user
*)arg
, sizeof(*vol
));
1228 return PTR_ERR(vol
);
1231 case BTRFS_IOC_SCAN_DEV
:
1232 ret
= btrfs_scan_one_device(vol
->name
, FMODE_READ
,
1233 &btrfs_fs_type
, &fs_devices
);
1241 static int btrfs_freeze(struct super_block
*sb
)
1243 struct btrfs_root
*root
= btrfs_sb(sb
);
1244 mutex_lock(&root
->fs_info
->transaction_kthread_mutex
);
1245 mutex_lock(&root
->fs_info
->cleaner_mutex
);
1249 static int btrfs_unfreeze(struct super_block
*sb
)
1251 struct btrfs_root
*root
= btrfs_sb(sb
);
1252 mutex_unlock(&root
->fs_info
->cleaner_mutex
);
1253 mutex_unlock(&root
->fs_info
->transaction_kthread_mutex
);
1257 static const struct super_operations btrfs_super_ops
= {
1258 .drop_inode
= btrfs_drop_inode
,
1259 .evict_inode
= btrfs_evict_inode
,
1260 .put_super
= btrfs_put_super
,
1261 .sync_fs
= btrfs_sync_fs
,
1262 .show_options
= btrfs_show_options
,
1263 .write_inode
= btrfs_write_inode
,
1264 .dirty_inode
= btrfs_dirty_inode
,
1265 .alloc_inode
= btrfs_alloc_inode
,
1266 .destroy_inode
= btrfs_destroy_inode
,
1267 .statfs
= btrfs_statfs
,
1268 .remount_fs
= btrfs_remount
,
1269 .freeze_fs
= btrfs_freeze
,
1270 .unfreeze_fs
= btrfs_unfreeze
,
1273 static const struct file_operations btrfs_ctl_fops
= {
1274 .unlocked_ioctl
= btrfs_control_ioctl
,
1275 .compat_ioctl
= btrfs_control_ioctl
,
1276 .owner
= THIS_MODULE
,
1277 .llseek
= noop_llseek
,
1280 static struct miscdevice btrfs_misc
= {
1281 .minor
= BTRFS_MINOR
,
1282 .name
= "btrfs-control",
1283 .fops
= &btrfs_ctl_fops
1286 MODULE_ALIAS_MISCDEV(BTRFS_MINOR
);
1287 MODULE_ALIAS("devname:btrfs-control");
1289 static int btrfs_interface_init(void)
1291 return misc_register(&btrfs_misc
);
1294 static void btrfs_interface_exit(void)
1296 if (misc_deregister(&btrfs_misc
) < 0)
1297 printk(KERN_INFO
"misc_deregister failed for control device");
1300 static int __init
init_btrfs_fs(void)
1304 err
= btrfs_init_sysfs();
1308 err
= btrfs_init_compress();
1312 err
= btrfs_init_cachep();
1316 err
= extent_io_init();
1320 err
= extent_map_init();
1322 goto free_extent_io
;
1324 err
= btrfs_delayed_inode_init();
1326 goto free_extent_map
;
1328 err
= btrfs_interface_init();
1330 goto free_delayed_inode
;
1332 err
= register_filesystem(&btrfs_fs_type
);
1334 goto unregister_ioctl
;
1336 printk(KERN_INFO
"%s loaded\n", BTRFS_BUILD_VERSION
);
1340 btrfs_interface_exit();
1342 btrfs_delayed_inode_exit();
1348 btrfs_destroy_cachep();
1350 btrfs_exit_compress();
1356 static void __exit
exit_btrfs_fs(void)
1358 btrfs_destroy_cachep();
1359 btrfs_delayed_inode_exit();
1362 btrfs_interface_exit();
1363 unregister_filesystem(&btrfs_fs_type
);
1365 btrfs_cleanup_fs_uuids();
1366 btrfs_exit_compress();
1369 module_init(init_btrfs_fs
)
1370 module_exit(exit_btrfs_fs
)
1372 MODULE_LICENSE("GPL");