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Merge branch 'for-linus-4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/mason...
[GitHub/exynos8895/android_kernel_samsung_universal8895.git] / fs / btrfs / super.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/blkdev.h>
20 #include <linux/module.h>
21 #include <linux/buffer_head.h>
22 #include <linux/fs.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/ratelimit.h>
44 #include <linux/btrfs.h>
45 #include "delayed-inode.h"
46 #include "ctree.h"
47 #include "disk-io.h"
48 #include "transaction.h"
49 #include "btrfs_inode.h"
50 #include "print-tree.h"
51 #include "hash.h"
52 #include "props.h"
53 #include "xattr.h"
54 #include "volumes.h"
55 #include "export.h"
56 #include "compression.h"
57 #include "rcu-string.h"
58 #include "dev-replace.h"
59 #include "free-space-cache.h"
60 #include "backref.h"
61 #include "tests/btrfs-tests.h"
62
63 #include "qgroup.h"
64 #define CREATE_TRACE_POINTS
65 #include <trace/events/btrfs.h>
66
67 static const struct super_operations btrfs_super_ops;
68 static struct file_system_type btrfs_fs_type;
69
70 static int btrfs_remount(struct super_block *sb, int *flags, char *data);
71
72 const char *btrfs_decode_error(int errno)
73 {
74 char *errstr = "unknown";
75
76 switch (errno) {
77 case -EIO:
78 errstr = "IO failure";
79 break;
80 case -ENOMEM:
81 errstr = "Out of memory";
82 break;
83 case -EROFS:
84 errstr = "Readonly filesystem";
85 break;
86 case -EEXIST:
87 errstr = "Object already exists";
88 break;
89 case -ENOSPC:
90 errstr = "No space left";
91 break;
92 case -ENOENT:
93 errstr = "No such entry";
94 break;
95 }
96
97 return errstr;
98 }
99
100 static void save_error_info(struct btrfs_fs_info *fs_info)
101 {
102 /*
103 * today we only save the error info into ram. Long term we'll
104 * also send it down to the disk
105 */
106 set_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state);
107 }
108
109 /* btrfs handle error by forcing the filesystem readonly */
110 static void btrfs_handle_error(struct btrfs_fs_info *fs_info)
111 {
112 struct super_block *sb = fs_info->sb;
113
114 if (sb->s_flags & MS_RDONLY)
115 return;
116
117 if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
118 sb->s_flags |= MS_RDONLY;
119 btrfs_info(fs_info, "forced readonly");
120 /*
121 * Note that a running device replace operation is not
122 * canceled here although there is no way to update
123 * the progress. It would add the risk of a deadlock,
124 * therefore the canceling is ommited. The only penalty
125 * is that some I/O remains active until the procedure
126 * completes. The next time when the filesystem is
127 * mounted writeable again, the device replace
128 * operation continues.
129 */
130 }
131 }
132
133 #ifdef CONFIG_PRINTK
134 /*
135 * __btrfs_std_error decodes expected errors from the caller and
136 * invokes the approciate error response.
137 */
138 __cold
139 void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function,
140 unsigned int line, int errno, const char *fmt, ...)
141 {
142 struct super_block *sb = fs_info->sb;
143 const char *errstr;
144
145 /*
146 * Special case: if the error is EROFS, and we're already
147 * under MS_RDONLY, then it is safe here.
148 */
149 if (errno == -EROFS && (sb->s_flags & MS_RDONLY))
150 return;
151
152 errstr = btrfs_decode_error(errno);
153 if (fmt) {
154 struct va_format vaf;
155 va_list args;
156
157 va_start(args, fmt);
158 vaf.fmt = fmt;
159 vaf.va = &args;
160
161 printk(KERN_CRIT
162 "BTRFS: error (device %s) in %s:%d: errno=%d %s (%pV)\n",
163 sb->s_id, function, line, errno, errstr, &vaf);
164 va_end(args);
165 } else {
166 printk(KERN_CRIT "BTRFS: error (device %s) in %s:%d: errno=%d %s\n",
167 sb->s_id, function, line, errno, errstr);
168 }
169
170 /* Don't go through full error handling during mount */
171 save_error_info(fs_info);
172 if (sb->s_flags & MS_BORN)
173 btrfs_handle_error(fs_info);
174 }
175
176 static const char * const logtypes[] = {
177 "emergency",
178 "alert",
179 "critical",
180 "error",
181 "warning",
182 "notice",
183 "info",
184 "debug",
185 };
186
187 void btrfs_printk(const struct btrfs_fs_info *fs_info, const char *fmt, ...)
188 {
189 struct super_block *sb = fs_info->sb;
190 char lvl[4];
191 struct va_format vaf;
192 va_list args;
193 const char *type = logtypes[4];
194 int kern_level;
195
196 va_start(args, fmt);
197
198 kern_level = printk_get_level(fmt);
199 if (kern_level) {
200 size_t size = printk_skip_level(fmt) - fmt;
201 memcpy(lvl, fmt, size);
202 lvl[size] = '\0';
203 fmt += size;
204 type = logtypes[kern_level - '0'];
205 } else
206 *lvl = '\0';
207
208 vaf.fmt = fmt;
209 vaf.va = &args;
210
211 printk("%sBTRFS %s (device %s): %pV\n", lvl, type, sb->s_id, &vaf);
212
213 va_end(args);
214 }
215
216 #else
217
218 void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function,
219 unsigned int line, int errno, const char *fmt, ...)
220 {
221 struct super_block *sb = fs_info->sb;
222
223 /*
224 * Special case: if the error is EROFS, and we're already
225 * under MS_RDONLY, then it is safe here.
226 */
227 if (errno == -EROFS && (sb->s_flags & MS_RDONLY))
228 return;
229
230 /* Don't go through full error handling during mount */
231 if (sb->s_flags & MS_BORN) {
232 save_error_info(fs_info);
233 btrfs_handle_error(fs_info);
234 }
235 }
236 #endif
237
238 /*
239 * We only mark the transaction aborted and then set the file system read-only.
240 * This will prevent new transactions from starting or trying to join this
241 * one.
242 *
243 * This means that error recovery at the call site is limited to freeing
244 * any local memory allocations and passing the error code up without
245 * further cleanup. The transaction should complete as it normally would
246 * in the call path but will return -EIO.
247 *
248 * We'll complete the cleanup in btrfs_end_transaction and
249 * btrfs_commit_transaction.
250 */
251 __cold
252 void __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
253 struct btrfs_root *root, const char *function,
254 unsigned int line, int errno)
255 {
256 trans->aborted = errno;
257 /* Nothing used. The other threads that have joined this
258 * transaction may be able to continue. */
259 if (!trans->blocks_used && list_empty(&trans->new_bgs)) {
260 const char *errstr;
261
262 errstr = btrfs_decode_error(errno);
263 btrfs_warn(root->fs_info,
264 "%s:%d: Aborting unused transaction(%s).",
265 function, line, errstr);
266 return;
267 }
268 ACCESS_ONCE(trans->transaction->aborted) = errno;
269 /* Wake up anybody who may be waiting on this transaction */
270 wake_up(&root->fs_info->transaction_wait);
271 wake_up(&root->fs_info->transaction_blocked_wait);
272 __btrfs_std_error(root->fs_info, function, line, errno, NULL);
273 }
274 /*
275 * __btrfs_panic decodes unexpected, fatal errors from the caller,
276 * issues an alert, and either panics or BUGs, depending on mount options.
277 */
278 __cold
279 void __btrfs_panic(struct btrfs_fs_info *fs_info, const char *function,
280 unsigned int line, int errno, const char *fmt, ...)
281 {
282 char *s_id = "<unknown>";
283 const char *errstr;
284 struct va_format vaf = { .fmt = fmt };
285 va_list args;
286
287 if (fs_info)
288 s_id = fs_info->sb->s_id;
289
290 va_start(args, fmt);
291 vaf.va = &args;
292
293 errstr = btrfs_decode_error(errno);
294 if (fs_info && (fs_info->mount_opt & BTRFS_MOUNT_PANIC_ON_FATAL_ERROR))
295 panic(KERN_CRIT "BTRFS panic (device %s) in %s:%d: %pV (errno=%d %s)\n",
296 s_id, function, line, &vaf, errno, errstr);
297
298 btrfs_crit(fs_info, "panic in %s:%d: %pV (errno=%d %s)",
299 function, line, &vaf, errno, errstr);
300 va_end(args);
301 /* Caller calls BUG() */
302 }
303
304 static void btrfs_put_super(struct super_block *sb)
305 {
306 close_ctree(btrfs_sb(sb)->tree_root);
307 }
308
309 enum {
310 Opt_degraded, Opt_subvol, Opt_subvolid, Opt_device, Opt_nodatasum,
311 Opt_nodatacow, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd,
312 Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl, Opt_compress,
313 Opt_compress_type, Opt_compress_force, Opt_compress_force_type,
314 Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard,
315 Opt_space_cache, Opt_clear_cache, Opt_user_subvol_rm_allowed,
316 Opt_enospc_debug, Opt_subvolrootid, Opt_defrag, Opt_inode_cache,
317 Opt_no_space_cache, Opt_recovery, Opt_skip_balance,
318 Opt_check_integrity, Opt_check_integrity_including_extent_data,
319 Opt_check_integrity_print_mask, Opt_fatal_errors, Opt_rescan_uuid_tree,
320 Opt_commit_interval, Opt_barrier, Opt_nodefrag, Opt_nodiscard,
321 Opt_noenospc_debug, Opt_noflushoncommit, Opt_acl, Opt_datacow,
322 Opt_datasum, Opt_treelog, Opt_noinode_cache,
323 Opt_err,
324 };
325
326 static match_table_t tokens = {
327 {Opt_degraded, "degraded"},
328 {Opt_subvol, "subvol=%s"},
329 {Opt_subvolid, "subvolid=%s"},
330 {Opt_device, "device=%s"},
331 {Opt_nodatasum, "nodatasum"},
332 {Opt_datasum, "datasum"},
333 {Opt_nodatacow, "nodatacow"},
334 {Opt_datacow, "datacow"},
335 {Opt_nobarrier, "nobarrier"},
336 {Opt_barrier, "barrier"},
337 {Opt_max_inline, "max_inline=%s"},
338 {Opt_alloc_start, "alloc_start=%s"},
339 {Opt_thread_pool, "thread_pool=%d"},
340 {Opt_compress, "compress"},
341 {Opt_compress_type, "compress=%s"},
342 {Opt_compress_force, "compress-force"},
343 {Opt_compress_force_type, "compress-force=%s"},
344 {Opt_ssd, "ssd"},
345 {Opt_ssd_spread, "ssd_spread"},
346 {Opt_nossd, "nossd"},
347 {Opt_acl, "acl"},
348 {Opt_noacl, "noacl"},
349 {Opt_notreelog, "notreelog"},
350 {Opt_treelog, "treelog"},
351 {Opt_flushoncommit, "flushoncommit"},
352 {Opt_noflushoncommit, "noflushoncommit"},
353 {Opt_ratio, "metadata_ratio=%d"},
354 {Opt_discard, "discard"},
355 {Opt_nodiscard, "nodiscard"},
356 {Opt_space_cache, "space_cache"},
357 {Opt_clear_cache, "clear_cache"},
358 {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
359 {Opt_enospc_debug, "enospc_debug"},
360 {Opt_noenospc_debug, "noenospc_debug"},
361 {Opt_subvolrootid, "subvolrootid=%d"},
362 {Opt_defrag, "autodefrag"},
363 {Opt_nodefrag, "noautodefrag"},
364 {Opt_inode_cache, "inode_cache"},
365 {Opt_noinode_cache, "noinode_cache"},
366 {Opt_no_space_cache, "nospace_cache"},
367 {Opt_recovery, "recovery"},
368 {Opt_skip_balance, "skip_balance"},
369 {Opt_check_integrity, "check_int"},
370 {Opt_check_integrity_including_extent_data, "check_int_data"},
371 {Opt_check_integrity_print_mask, "check_int_print_mask=%d"},
372 {Opt_rescan_uuid_tree, "rescan_uuid_tree"},
373 {Opt_fatal_errors, "fatal_errors=%s"},
374 {Opt_commit_interval, "commit=%d"},
375 {Opt_err, NULL},
376 };
377
378 /*
379 * Regular mount options parser. Everything that is needed only when
380 * reading in a new superblock is parsed here.
381 * XXX JDM: This needs to be cleaned up for remount.
382 */
383 int btrfs_parse_options(struct btrfs_root *root, char *options)
384 {
385 struct btrfs_fs_info *info = root->fs_info;
386 substring_t args[MAX_OPT_ARGS];
387 char *p, *num, *orig = NULL;
388 u64 cache_gen;
389 int intarg;
390 int ret = 0;
391 char *compress_type;
392 bool compress_force = false;
393
394 cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
395 if (cache_gen)
396 btrfs_set_opt(info->mount_opt, SPACE_CACHE);
397
398 if (!options)
399 goto out;
400
401 /*
402 * strsep changes the string, duplicate it because parse_options
403 * gets called twice
404 */
405 options = kstrdup(options, GFP_NOFS);
406 if (!options)
407 return -ENOMEM;
408
409 orig = options;
410
411 while ((p = strsep(&options, ",")) != NULL) {
412 int token;
413 if (!*p)
414 continue;
415
416 token = match_token(p, tokens, args);
417 switch (token) {
418 case Opt_degraded:
419 btrfs_info(root->fs_info, "allowing degraded mounts");
420 btrfs_set_opt(info->mount_opt, DEGRADED);
421 break;
422 case Opt_subvol:
423 case Opt_subvolid:
424 case Opt_subvolrootid:
425 case Opt_device:
426 /*
427 * These are parsed by btrfs_parse_early_options
428 * and can be happily ignored here.
429 */
430 break;
431 case Opt_nodatasum:
432 btrfs_set_and_info(root, NODATASUM,
433 "setting nodatasum");
434 break;
435 case Opt_datasum:
436 if (btrfs_test_opt(root, NODATASUM)) {
437 if (btrfs_test_opt(root, NODATACOW))
438 btrfs_info(root->fs_info, "setting datasum, datacow enabled");
439 else
440 btrfs_info(root->fs_info, "setting datasum");
441 }
442 btrfs_clear_opt(info->mount_opt, NODATACOW);
443 btrfs_clear_opt(info->mount_opt, NODATASUM);
444 break;
445 case Opt_nodatacow:
446 if (!btrfs_test_opt(root, NODATACOW)) {
447 if (!btrfs_test_opt(root, COMPRESS) ||
448 !btrfs_test_opt(root, FORCE_COMPRESS)) {
449 btrfs_info(root->fs_info,
450 "setting nodatacow, compression disabled");
451 } else {
452 btrfs_info(root->fs_info, "setting nodatacow");
453 }
454 }
455 btrfs_clear_opt(info->mount_opt, COMPRESS);
456 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
457 btrfs_set_opt(info->mount_opt, NODATACOW);
458 btrfs_set_opt(info->mount_opt, NODATASUM);
459 break;
460 case Opt_datacow:
461 btrfs_clear_and_info(root, NODATACOW,
462 "setting datacow");
463 break;
464 case Opt_compress_force:
465 case Opt_compress_force_type:
466 compress_force = true;
467 /* Fallthrough */
468 case Opt_compress:
469 case Opt_compress_type:
470 if (token == Opt_compress ||
471 token == Opt_compress_force ||
472 strcmp(args[0].from, "zlib") == 0) {
473 compress_type = "zlib";
474 info->compress_type = BTRFS_COMPRESS_ZLIB;
475 btrfs_set_opt(info->mount_opt, COMPRESS);
476 btrfs_clear_opt(info->mount_opt, NODATACOW);
477 btrfs_clear_opt(info->mount_opt, NODATASUM);
478 } else if (strcmp(args[0].from, "lzo") == 0) {
479 compress_type = "lzo";
480 info->compress_type = BTRFS_COMPRESS_LZO;
481 btrfs_set_opt(info->mount_opt, COMPRESS);
482 btrfs_clear_opt(info->mount_opt, NODATACOW);
483 btrfs_clear_opt(info->mount_opt, NODATASUM);
484 btrfs_set_fs_incompat(info, COMPRESS_LZO);
485 } else if (strncmp(args[0].from, "no", 2) == 0) {
486 compress_type = "no";
487 btrfs_clear_opt(info->mount_opt, COMPRESS);
488 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
489 compress_force = false;
490 } else {
491 ret = -EINVAL;
492 goto out;
493 }
494
495 if (compress_force) {
496 btrfs_set_and_info(root, FORCE_COMPRESS,
497 "force %s compression",
498 compress_type);
499 } else {
500 if (!btrfs_test_opt(root, COMPRESS))
501 btrfs_info(root->fs_info,
502 "btrfs: use %s compression",
503 compress_type);
504 /*
505 * If we remount from compress-force=xxx to
506 * compress=xxx, we need clear FORCE_COMPRESS
507 * flag, otherwise, there is no way for users
508 * to disable forcible compression separately.
509 */
510 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
511 }
512 break;
513 case Opt_ssd:
514 btrfs_set_and_info(root, SSD,
515 "use ssd allocation scheme");
516 break;
517 case Opt_ssd_spread:
518 btrfs_set_and_info(root, SSD_SPREAD,
519 "use spread ssd allocation scheme");
520 btrfs_set_opt(info->mount_opt, SSD);
521 break;
522 case Opt_nossd:
523 btrfs_set_and_info(root, NOSSD,
524 "not using ssd allocation scheme");
525 btrfs_clear_opt(info->mount_opt, SSD);
526 break;
527 case Opt_barrier:
528 btrfs_clear_and_info(root, NOBARRIER,
529 "turning on barriers");
530 break;
531 case Opt_nobarrier:
532 btrfs_set_and_info(root, NOBARRIER,
533 "turning off barriers");
534 break;
535 case Opt_thread_pool:
536 ret = match_int(&args[0], &intarg);
537 if (ret) {
538 goto out;
539 } else if (intarg > 0) {
540 info->thread_pool_size = intarg;
541 } else {
542 ret = -EINVAL;
543 goto out;
544 }
545 break;
546 case Opt_max_inline:
547 num = match_strdup(&args[0]);
548 if (num) {
549 info->max_inline = memparse(num, NULL);
550 kfree(num);
551
552 if (info->max_inline) {
553 info->max_inline = min_t(u64,
554 info->max_inline,
555 root->sectorsize);
556 }
557 btrfs_info(root->fs_info, "max_inline at %llu",
558 info->max_inline);
559 } else {
560 ret = -ENOMEM;
561 goto out;
562 }
563 break;
564 case Opt_alloc_start:
565 num = match_strdup(&args[0]);
566 if (num) {
567 mutex_lock(&info->chunk_mutex);
568 info->alloc_start = memparse(num, NULL);
569 mutex_unlock(&info->chunk_mutex);
570 kfree(num);
571 btrfs_info(root->fs_info, "allocations start at %llu",
572 info->alloc_start);
573 } else {
574 ret = -ENOMEM;
575 goto out;
576 }
577 break;
578 case Opt_acl:
579 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
580 root->fs_info->sb->s_flags |= MS_POSIXACL;
581 break;
582 #else
583 btrfs_err(root->fs_info,
584 "support for ACL not compiled in!");
585 ret = -EINVAL;
586 goto out;
587 #endif
588 case Opt_noacl:
589 root->fs_info->sb->s_flags &= ~MS_POSIXACL;
590 break;
591 case Opt_notreelog:
592 btrfs_set_and_info(root, NOTREELOG,
593 "disabling tree log");
594 break;
595 case Opt_treelog:
596 btrfs_clear_and_info(root, NOTREELOG,
597 "enabling tree log");
598 break;
599 case Opt_flushoncommit:
600 btrfs_set_and_info(root, FLUSHONCOMMIT,
601 "turning on flush-on-commit");
602 break;
603 case Opt_noflushoncommit:
604 btrfs_clear_and_info(root, FLUSHONCOMMIT,
605 "turning off flush-on-commit");
606 break;
607 case Opt_ratio:
608 ret = match_int(&args[0], &intarg);
609 if (ret) {
610 goto out;
611 } else if (intarg >= 0) {
612 info->metadata_ratio = intarg;
613 btrfs_info(root->fs_info, "metadata ratio %d",
614 info->metadata_ratio);
615 } else {
616 ret = -EINVAL;
617 goto out;
618 }
619 break;
620 case Opt_discard:
621 btrfs_set_and_info(root, DISCARD,
622 "turning on discard");
623 break;
624 case Opt_nodiscard:
625 btrfs_clear_and_info(root, DISCARD,
626 "turning off discard");
627 break;
628 case Opt_space_cache:
629 btrfs_set_and_info(root, SPACE_CACHE,
630 "enabling disk space caching");
631 break;
632 case Opt_rescan_uuid_tree:
633 btrfs_set_opt(info->mount_opt, RESCAN_UUID_TREE);
634 break;
635 case Opt_no_space_cache:
636 btrfs_clear_and_info(root, SPACE_CACHE,
637 "disabling disk space caching");
638 break;
639 case Opt_inode_cache:
640 btrfs_set_pending_and_info(info, INODE_MAP_CACHE,
641 "enabling inode map caching");
642 break;
643 case Opt_noinode_cache:
644 btrfs_clear_pending_and_info(info, INODE_MAP_CACHE,
645 "disabling inode map caching");
646 break;
647 case Opt_clear_cache:
648 btrfs_set_and_info(root, CLEAR_CACHE,
649 "force clearing of disk cache");
650 break;
651 case Opt_user_subvol_rm_allowed:
652 btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
653 break;
654 case Opt_enospc_debug:
655 btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
656 break;
657 case Opt_noenospc_debug:
658 btrfs_clear_opt(info->mount_opt, ENOSPC_DEBUG);
659 break;
660 case Opt_defrag:
661 btrfs_set_and_info(root, AUTO_DEFRAG,
662 "enabling auto defrag");
663 break;
664 case Opt_nodefrag:
665 btrfs_clear_and_info(root, AUTO_DEFRAG,
666 "disabling auto defrag");
667 break;
668 case Opt_recovery:
669 btrfs_info(root->fs_info, "enabling auto recovery");
670 btrfs_set_opt(info->mount_opt, RECOVERY);
671 break;
672 case Opt_skip_balance:
673 btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
674 break;
675 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
676 case Opt_check_integrity_including_extent_data:
677 btrfs_info(root->fs_info,
678 "enabling check integrity including extent data");
679 btrfs_set_opt(info->mount_opt,
680 CHECK_INTEGRITY_INCLUDING_EXTENT_DATA);
681 btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
682 break;
683 case Opt_check_integrity:
684 btrfs_info(root->fs_info, "enabling check integrity");
685 btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
686 break;
687 case Opt_check_integrity_print_mask:
688 ret = match_int(&args[0], &intarg);
689 if (ret) {
690 goto out;
691 } else if (intarg >= 0) {
692 info->check_integrity_print_mask = intarg;
693 btrfs_info(root->fs_info, "check_integrity_print_mask 0x%x",
694 info->check_integrity_print_mask);
695 } else {
696 ret = -EINVAL;
697 goto out;
698 }
699 break;
700 #else
701 case Opt_check_integrity_including_extent_data:
702 case Opt_check_integrity:
703 case Opt_check_integrity_print_mask:
704 btrfs_err(root->fs_info,
705 "support for check_integrity* not compiled in!");
706 ret = -EINVAL;
707 goto out;
708 #endif
709 case Opt_fatal_errors:
710 if (strcmp(args[0].from, "panic") == 0)
711 btrfs_set_opt(info->mount_opt,
712 PANIC_ON_FATAL_ERROR);
713 else if (strcmp(args[0].from, "bug") == 0)
714 btrfs_clear_opt(info->mount_opt,
715 PANIC_ON_FATAL_ERROR);
716 else {
717 ret = -EINVAL;
718 goto out;
719 }
720 break;
721 case Opt_commit_interval:
722 intarg = 0;
723 ret = match_int(&args[0], &intarg);
724 if (ret < 0) {
725 btrfs_err(root->fs_info, "invalid commit interval");
726 ret = -EINVAL;
727 goto out;
728 }
729 if (intarg > 0) {
730 if (intarg > 300) {
731 btrfs_warn(root->fs_info, "excessive commit interval %d",
732 intarg);
733 }
734 info->commit_interval = intarg;
735 } else {
736 btrfs_info(root->fs_info, "using default commit interval %ds",
737 BTRFS_DEFAULT_COMMIT_INTERVAL);
738 info->commit_interval = BTRFS_DEFAULT_COMMIT_INTERVAL;
739 }
740 break;
741 case Opt_err:
742 btrfs_info(root->fs_info, "unrecognized mount option '%s'", p);
743 ret = -EINVAL;
744 goto out;
745 default:
746 break;
747 }
748 }
749 out:
750 if (!ret && btrfs_test_opt(root, SPACE_CACHE))
751 btrfs_info(root->fs_info, "disk space caching is enabled");
752 kfree(orig);
753 return ret;
754 }
755
756 /*
757 * Parse mount options that are required early in the mount process.
758 *
759 * All other options will be parsed on much later in the mount process and
760 * only when we need to allocate a new super block.
761 */
762 static int btrfs_parse_early_options(const char *options, fmode_t flags,
763 void *holder, char **subvol_name, u64 *subvol_objectid,
764 struct btrfs_fs_devices **fs_devices)
765 {
766 substring_t args[MAX_OPT_ARGS];
767 char *device_name, *opts, *orig, *p;
768 char *num = NULL;
769 int error = 0;
770
771 if (!options)
772 return 0;
773
774 /*
775 * strsep changes the string, duplicate it because parse_options
776 * gets called twice
777 */
778 opts = kstrdup(options, GFP_KERNEL);
779 if (!opts)
780 return -ENOMEM;
781 orig = opts;
782
783 while ((p = strsep(&opts, ",")) != NULL) {
784 int token;
785 if (!*p)
786 continue;
787
788 token = match_token(p, tokens, args);
789 switch (token) {
790 case Opt_subvol:
791 kfree(*subvol_name);
792 *subvol_name = match_strdup(&args[0]);
793 if (!*subvol_name) {
794 error = -ENOMEM;
795 goto out;
796 }
797 break;
798 case Opt_subvolid:
799 num = match_strdup(&args[0]);
800 if (num) {
801 *subvol_objectid = memparse(num, NULL);
802 kfree(num);
803 /* we want the original fs_tree */
804 if (!*subvol_objectid)
805 *subvol_objectid =
806 BTRFS_FS_TREE_OBJECTID;
807 } else {
808 error = -EINVAL;
809 goto out;
810 }
811 break;
812 case Opt_subvolrootid:
813 printk(KERN_WARNING
814 "BTRFS: 'subvolrootid' mount option is deprecated and has "
815 "no effect\n");
816 break;
817 case Opt_device:
818 device_name = match_strdup(&args[0]);
819 if (!device_name) {
820 error = -ENOMEM;
821 goto out;
822 }
823 error = btrfs_scan_one_device(device_name,
824 flags, holder, fs_devices);
825 kfree(device_name);
826 if (error)
827 goto out;
828 break;
829 default:
830 break;
831 }
832 }
833
834 out:
835 kfree(orig);
836 return error;
837 }
838
839 static char *get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
840 u64 subvol_objectid)
841 {
842 struct btrfs_root *root = fs_info->tree_root;
843 struct btrfs_root *fs_root;
844 struct btrfs_root_ref *root_ref;
845 struct btrfs_inode_ref *inode_ref;
846 struct btrfs_key key;
847 struct btrfs_path *path = NULL;
848 char *name = NULL, *ptr;
849 u64 dirid;
850 int len;
851 int ret;
852
853 path = btrfs_alloc_path();
854 if (!path) {
855 ret = -ENOMEM;
856 goto err;
857 }
858 path->leave_spinning = 1;
859
860 name = kmalloc(PATH_MAX, GFP_NOFS);
861 if (!name) {
862 ret = -ENOMEM;
863 goto err;
864 }
865 ptr = name + PATH_MAX - 1;
866 ptr[0] = '\0';
867
868 /*
869 * Walk up the subvolume trees in the tree of tree roots by root
870 * backrefs until we hit the top-level subvolume.
871 */
872 while (subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
873 key.objectid = subvol_objectid;
874 key.type = BTRFS_ROOT_BACKREF_KEY;
875 key.offset = (u64)-1;
876
877 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
878 if (ret < 0) {
879 goto err;
880 } else if (ret > 0) {
881 ret = btrfs_previous_item(root, path, subvol_objectid,
882 BTRFS_ROOT_BACKREF_KEY);
883 if (ret < 0) {
884 goto err;
885 } else if (ret > 0) {
886 ret = -ENOENT;
887 goto err;
888 }
889 }
890
891 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
892 subvol_objectid = key.offset;
893
894 root_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
895 struct btrfs_root_ref);
896 len = btrfs_root_ref_name_len(path->nodes[0], root_ref);
897 ptr -= len + 1;
898 if (ptr < name) {
899 ret = -ENAMETOOLONG;
900 goto err;
901 }
902 read_extent_buffer(path->nodes[0], ptr + 1,
903 (unsigned long)(root_ref + 1), len);
904 ptr[0] = '/';
905 dirid = btrfs_root_ref_dirid(path->nodes[0], root_ref);
906 btrfs_release_path(path);
907
908 key.objectid = subvol_objectid;
909 key.type = BTRFS_ROOT_ITEM_KEY;
910 key.offset = (u64)-1;
911 fs_root = btrfs_read_fs_root_no_name(fs_info, &key);
912 if (IS_ERR(fs_root)) {
913 ret = PTR_ERR(fs_root);
914 goto err;
915 }
916
917 /*
918 * Walk up the filesystem tree by inode refs until we hit the
919 * root directory.
920 */
921 while (dirid != BTRFS_FIRST_FREE_OBJECTID) {
922 key.objectid = dirid;
923 key.type = BTRFS_INODE_REF_KEY;
924 key.offset = (u64)-1;
925
926 ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0);
927 if (ret < 0) {
928 goto err;
929 } else if (ret > 0) {
930 ret = btrfs_previous_item(fs_root, path, dirid,
931 BTRFS_INODE_REF_KEY);
932 if (ret < 0) {
933 goto err;
934 } else if (ret > 0) {
935 ret = -ENOENT;
936 goto err;
937 }
938 }
939
940 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
941 dirid = key.offset;
942
943 inode_ref = btrfs_item_ptr(path->nodes[0],
944 path->slots[0],
945 struct btrfs_inode_ref);
946 len = btrfs_inode_ref_name_len(path->nodes[0],
947 inode_ref);
948 ptr -= len + 1;
949 if (ptr < name) {
950 ret = -ENAMETOOLONG;
951 goto err;
952 }
953 read_extent_buffer(path->nodes[0], ptr + 1,
954 (unsigned long)(inode_ref + 1), len);
955 ptr[0] = '/';
956 btrfs_release_path(path);
957 }
958 }
959
960 btrfs_free_path(path);
961 if (ptr == name + PATH_MAX - 1) {
962 name[0] = '/';
963 name[1] = '\0';
964 } else {
965 memmove(name, ptr, name + PATH_MAX - ptr);
966 }
967 return name;
968
969 err:
970 btrfs_free_path(path);
971 kfree(name);
972 return ERR_PTR(ret);
973 }
974
975 static int get_default_subvol_objectid(struct btrfs_fs_info *fs_info, u64 *objectid)
976 {
977 struct btrfs_root *root = fs_info->tree_root;
978 struct btrfs_dir_item *di;
979 struct btrfs_path *path;
980 struct btrfs_key location;
981 u64 dir_id;
982
983 path = btrfs_alloc_path();
984 if (!path)
985 return -ENOMEM;
986 path->leave_spinning = 1;
987
988 /*
989 * Find the "default" dir item which points to the root item that we
990 * will mount by default if we haven't been given a specific subvolume
991 * to mount.
992 */
993 dir_id = btrfs_super_root_dir(fs_info->super_copy);
994 di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
995 if (IS_ERR(di)) {
996 btrfs_free_path(path);
997 return PTR_ERR(di);
998 }
999 if (!di) {
1000 /*
1001 * Ok the default dir item isn't there. This is weird since
1002 * it's always been there, but don't freak out, just try and
1003 * mount the top-level subvolume.
1004 */
1005 btrfs_free_path(path);
1006 *objectid = BTRFS_FS_TREE_OBJECTID;
1007 return 0;
1008 }
1009
1010 btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
1011 btrfs_free_path(path);
1012 *objectid = location.objectid;
1013 return 0;
1014 }
1015
1016 static int btrfs_fill_super(struct super_block *sb,
1017 struct btrfs_fs_devices *fs_devices,
1018 void *data, int silent)
1019 {
1020 struct inode *inode;
1021 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1022 struct btrfs_key key;
1023 int err;
1024
1025 sb->s_maxbytes = MAX_LFS_FILESIZE;
1026 sb->s_magic = BTRFS_SUPER_MAGIC;
1027 sb->s_op = &btrfs_super_ops;
1028 sb->s_d_op = &btrfs_dentry_operations;
1029 sb->s_export_op = &btrfs_export_ops;
1030 sb->s_xattr = btrfs_xattr_handlers;
1031 sb->s_time_gran = 1;
1032 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
1033 sb->s_flags |= MS_POSIXACL;
1034 #endif
1035 sb->s_flags |= MS_I_VERSION;
1036 sb->s_iflags |= SB_I_CGROUPWB;
1037 err = open_ctree(sb, fs_devices, (char *)data);
1038 if (err) {
1039 printk(KERN_ERR "BTRFS: open_ctree failed\n");
1040 return err;
1041 }
1042
1043 key.objectid = BTRFS_FIRST_FREE_OBJECTID;
1044 key.type = BTRFS_INODE_ITEM_KEY;
1045 key.offset = 0;
1046 inode = btrfs_iget(sb, &key, fs_info->fs_root, NULL);
1047 if (IS_ERR(inode)) {
1048 err = PTR_ERR(inode);
1049 goto fail_close;
1050 }
1051
1052 sb->s_root = d_make_root(inode);
1053 if (!sb->s_root) {
1054 err = -ENOMEM;
1055 goto fail_close;
1056 }
1057
1058 save_mount_options(sb, data);
1059 cleancache_init_fs(sb);
1060 sb->s_flags |= MS_ACTIVE;
1061 return 0;
1062
1063 fail_close:
1064 close_ctree(fs_info->tree_root);
1065 return err;
1066 }
1067
1068 int btrfs_sync_fs(struct super_block *sb, int wait)
1069 {
1070 struct btrfs_trans_handle *trans;
1071 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1072 struct btrfs_root *root = fs_info->tree_root;
1073
1074 trace_btrfs_sync_fs(wait);
1075
1076 if (!wait) {
1077 filemap_flush(fs_info->btree_inode->i_mapping);
1078 return 0;
1079 }
1080
1081 btrfs_wait_ordered_roots(fs_info, -1);
1082
1083 trans = btrfs_attach_transaction_barrier(root);
1084 if (IS_ERR(trans)) {
1085 /* no transaction, don't bother */
1086 if (PTR_ERR(trans) == -ENOENT) {
1087 /*
1088 * Exit unless we have some pending changes
1089 * that need to go through commit
1090 */
1091 if (fs_info->pending_changes == 0)
1092 return 0;
1093 /*
1094 * A non-blocking test if the fs is frozen. We must not
1095 * start a new transaction here otherwise a deadlock
1096 * happens. The pending operations are delayed to the
1097 * next commit after thawing.
1098 */
1099 if (__sb_start_write(sb, SB_FREEZE_WRITE, false))
1100 __sb_end_write(sb, SB_FREEZE_WRITE);
1101 else
1102 return 0;
1103 trans = btrfs_start_transaction(root, 0);
1104 }
1105 if (IS_ERR(trans))
1106 return PTR_ERR(trans);
1107 }
1108 return btrfs_commit_transaction(trans, root);
1109 }
1110
1111 static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
1112 {
1113 struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
1114 struct btrfs_root *root = info->tree_root;
1115 char *compress_type;
1116
1117 if (btrfs_test_opt(root, DEGRADED))
1118 seq_puts(seq, ",degraded");
1119 if (btrfs_test_opt(root, NODATASUM))
1120 seq_puts(seq, ",nodatasum");
1121 if (btrfs_test_opt(root, NODATACOW))
1122 seq_puts(seq, ",nodatacow");
1123 if (btrfs_test_opt(root, NOBARRIER))
1124 seq_puts(seq, ",nobarrier");
1125 if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE)
1126 seq_printf(seq, ",max_inline=%llu", info->max_inline);
1127 if (info->alloc_start != 0)
1128 seq_printf(seq, ",alloc_start=%llu", info->alloc_start);
1129 if (info->thread_pool_size != min_t(unsigned long,
1130 num_online_cpus() + 2, 8))
1131 seq_printf(seq, ",thread_pool=%d", info->thread_pool_size);
1132 if (btrfs_test_opt(root, COMPRESS)) {
1133 if (info->compress_type == BTRFS_COMPRESS_ZLIB)
1134 compress_type = "zlib";
1135 else
1136 compress_type = "lzo";
1137 if (btrfs_test_opt(root, FORCE_COMPRESS))
1138 seq_printf(seq, ",compress-force=%s", compress_type);
1139 else
1140 seq_printf(seq, ",compress=%s", compress_type);
1141 }
1142 if (btrfs_test_opt(root, NOSSD))
1143 seq_puts(seq, ",nossd");
1144 if (btrfs_test_opt(root, SSD_SPREAD))
1145 seq_puts(seq, ",ssd_spread");
1146 else if (btrfs_test_opt(root, SSD))
1147 seq_puts(seq, ",ssd");
1148 if (btrfs_test_opt(root, NOTREELOG))
1149 seq_puts(seq, ",notreelog");
1150 if (btrfs_test_opt(root, FLUSHONCOMMIT))
1151 seq_puts(seq, ",flushoncommit");
1152 if (btrfs_test_opt(root, DISCARD))
1153 seq_puts(seq, ",discard");
1154 if (!(root->fs_info->sb->s_flags & MS_POSIXACL))
1155 seq_puts(seq, ",noacl");
1156 if (btrfs_test_opt(root, SPACE_CACHE))
1157 seq_puts(seq, ",space_cache");
1158 else
1159 seq_puts(seq, ",nospace_cache");
1160 if (btrfs_test_opt(root, RESCAN_UUID_TREE))
1161 seq_puts(seq, ",rescan_uuid_tree");
1162 if (btrfs_test_opt(root, CLEAR_CACHE))
1163 seq_puts(seq, ",clear_cache");
1164 if (btrfs_test_opt(root, USER_SUBVOL_RM_ALLOWED))
1165 seq_puts(seq, ",user_subvol_rm_allowed");
1166 if (btrfs_test_opt(root, ENOSPC_DEBUG))
1167 seq_puts(seq, ",enospc_debug");
1168 if (btrfs_test_opt(root, AUTO_DEFRAG))
1169 seq_puts(seq, ",autodefrag");
1170 if (btrfs_test_opt(root, INODE_MAP_CACHE))
1171 seq_puts(seq, ",inode_cache");
1172 if (btrfs_test_opt(root, SKIP_BALANCE))
1173 seq_puts(seq, ",skip_balance");
1174 if (btrfs_test_opt(root, RECOVERY))
1175 seq_puts(seq, ",recovery");
1176 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
1177 if (btrfs_test_opt(root, CHECK_INTEGRITY_INCLUDING_EXTENT_DATA))
1178 seq_puts(seq, ",check_int_data");
1179 else if (btrfs_test_opt(root, CHECK_INTEGRITY))
1180 seq_puts(seq, ",check_int");
1181 if (info->check_integrity_print_mask)
1182 seq_printf(seq, ",check_int_print_mask=%d",
1183 info->check_integrity_print_mask);
1184 #endif
1185 if (info->metadata_ratio)
1186 seq_printf(seq, ",metadata_ratio=%d",
1187 info->metadata_ratio);
1188 if (btrfs_test_opt(root, PANIC_ON_FATAL_ERROR))
1189 seq_puts(seq, ",fatal_errors=panic");
1190 if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL)
1191 seq_printf(seq, ",commit=%d", info->commit_interval);
1192 seq_printf(seq, ",subvolid=%llu",
1193 BTRFS_I(d_inode(dentry))->root->root_key.objectid);
1194 seq_puts(seq, ",subvol=");
1195 seq_dentry(seq, dentry, " \t\n\\");
1196 return 0;
1197 }
1198
1199 static int btrfs_test_super(struct super_block *s, void *data)
1200 {
1201 struct btrfs_fs_info *p = data;
1202 struct btrfs_fs_info *fs_info = btrfs_sb(s);
1203
1204 return fs_info->fs_devices == p->fs_devices;
1205 }
1206
1207 static int btrfs_set_super(struct super_block *s, void *data)
1208 {
1209 int err = set_anon_super(s, data);
1210 if (!err)
1211 s->s_fs_info = data;
1212 return err;
1213 }
1214
1215 /*
1216 * subvolumes are identified by ino 256
1217 */
1218 static inline int is_subvolume_inode(struct inode *inode)
1219 {
1220 if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
1221 return 1;
1222 return 0;
1223 }
1224
1225 /*
1226 * This will add subvolid=0 to the argument string while removing any subvol=
1227 * and subvolid= arguments to make sure we get the top-level root for path
1228 * walking to the subvol we want.
1229 */
1230 static char *setup_root_args(char *args)
1231 {
1232 char *buf, *dst, *sep;
1233
1234 if (!args)
1235 return kstrdup("subvolid=0", GFP_NOFS);
1236
1237 /* The worst case is that we add ",subvolid=0" to the end. */
1238 buf = dst = kmalloc(strlen(args) + strlen(",subvolid=0") + 1, GFP_NOFS);
1239 if (!buf)
1240 return NULL;
1241
1242 while (1) {
1243 sep = strchrnul(args, ',');
1244 if (!strstarts(args, "subvol=") &&
1245 !strstarts(args, "subvolid=")) {
1246 memcpy(dst, args, sep - args);
1247 dst += sep - args;
1248 *dst++ = ',';
1249 }
1250 if (*sep)
1251 args = sep + 1;
1252 else
1253 break;
1254 }
1255 strcpy(dst, "subvolid=0");
1256
1257 return buf;
1258 }
1259
1260 static struct dentry *mount_subvol(const char *subvol_name, u64 subvol_objectid,
1261 int flags, const char *device_name,
1262 char *data)
1263 {
1264 struct dentry *root;
1265 struct vfsmount *mnt = NULL;
1266 char *newargs;
1267 int ret;
1268
1269 newargs = setup_root_args(data);
1270 if (!newargs) {
1271 root = ERR_PTR(-ENOMEM);
1272 goto out;
1273 }
1274
1275 mnt = vfs_kern_mount(&btrfs_fs_type, flags, device_name, newargs);
1276 if (PTR_ERR_OR_ZERO(mnt) == -EBUSY) {
1277 if (flags & MS_RDONLY) {
1278 mnt = vfs_kern_mount(&btrfs_fs_type, flags & ~MS_RDONLY,
1279 device_name, newargs);
1280 } else {
1281 mnt = vfs_kern_mount(&btrfs_fs_type, flags | MS_RDONLY,
1282 device_name, newargs);
1283 if (IS_ERR(mnt)) {
1284 root = ERR_CAST(mnt);
1285 mnt = NULL;
1286 goto out;
1287 }
1288
1289 down_write(&mnt->mnt_sb->s_umount);
1290 ret = btrfs_remount(mnt->mnt_sb, &flags, NULL);
1291 up_write(&mnt->mnt_sb->s_umount);
1292 if (ret < 0) {
1293 root = ERR_PTR(ret);
1294 goto out;
1295 }
1296 }
1297 }
1298 if (IS_ERR(mnt)) {
1299 root = ERR_CAST(mnt);
1300 mnt = NULL;
1301 goto out;
1302 }
1303
1304 if (!subvol_name) {
1305 if (!subvol_objectid) {
1306 ret = get_default_subvol_objectid(btrfs_sb(mnt->mnt_sb),
1307 &subvol_objectid);
1308 if (ret) {
1309 root = ERR_PTR(ret);
1310 goto out;
1311 }
1312 }
1313 subvol_name = get_subvol_name_from_objectid(btrfs_sb(mnt->mnt_sb),
1314 subvol_objectid);
1315 if (IS_ERR(subvol_name)) {
1316 root = ERR_CAST(subvol_name);
1317 subvol_name = NULL;
1318 goto out;
1319 }
1320
1321 }
1322
1323 root = mount_subtree(mnt, subvol_name);
1324 /* mount_subtree() drops our reference on the vfsmount. */
1325 mnt = NULL;
1326
1327 if (!IS_ERR(root)) {
1328 struct super_block *s = root->d_sb;
1329 struct inode *root_inode = d_inode(root);
1330 u64 root_objectid = BTRFS_I(root_inode)->root->root_key.objectid;
1331
1332 ret = 0;
1333 if (!is_subvolume_inode(root_inode)) {
1334 pr_err("BTRFS: '%s' is not a valid subvolume\n",
1335 subvol_name);
1336 ret = -EINVAL;
1337 }
1338 if (subvol_objectid && root_objectid != subvol_objectid) {
1339 /*
1340 * This will also catch a race condition where a
1341 * subvolume which was passed by ID is renamed and
1342 * another subvolume is renamed over the old location.
1343 */
1344 pr_err("BTRFS: subvol '%s' does not match subvolid %llu\n",
1345 subvol_name, subvol_objectid);
1346 ret = -EINVAL;
1347 }
1348 if (ret) {
1349 dput(root);
1350 root = ERR_PTR(ret);
1351 deactivate_locked_super(s);
1352 }
1353 }
1354
1355 out:
1356 mntput(mnt);
1357 kfree(newargs);
1358 kfree(subvol_name);
1359 return root;
1360 }
1361
1362 static int parse_security_options(char *orig_opts,
1363 struct security_mnt_opts *sec_opts)
1364 {
1365 char *secdata = NULL;
1366 int ret = 0;
1367
1368 secdata = alloc_secdata();
1369 if (!secdata)
1370 return -ENOMEM;
1371 ret = security_sb_copy_data(orig_opts, secdata);
1372 if (ret) {
1373 free_secdata(secdata);
1374 return ret;
1375 }
1376 ret = security_sb_parse_opts_str(secdata, sec_opts);
1377 free_secdata(secdata);
1378 return ret;
1379 }
1380
1381 static int setup_security_options(struct btrfs_fs_info *fs_info,
1382 struct super_block *sb,
1383 struct security_mnt_opts *sec_opts)
1384 {
1385 int ret = 0;
1386
1387 /*
1388 * Call security_sb_set_mnt_opts() to check whether new sec_opts
1389 * is valid.
1390 */
1391 ret = security_sb_set_mnt_opts(sb, sec_opts, 0, NULL);
1392 if (ret)
1393 return ret;
1394
1395 #ifdef CONFIG_SECURITY
1396 if (!fs_info->security_opts.num_mnt_opts) {
1397 /* first time security setup, copy sec_opts to fs_info */
1398 memcpy(&fs_info->security_opts, sec_opts, sizeof(*sec_opts));
1399 } else {
1400 /*
1401 * Since SELinux(the only one supports security_mnt_opts) does
1402 * NOT support changing context during remount/mount same sb,
1403 * This must be the same or part of the same security options,
1404 * just free it.
1405 */
1406 security_free_mnt_opts(sec_opts);
1407 }
1408 #endif
1409 return ret;
1410 }
1411
1412 /*
1413 * Find a superblock for the given device / mount point.
1414 *
1415 * Note: This is based on get_sb_bdev from fs/super.c with a few additions
1416 * for multiple device setup. Make sure to keep it in sync.
1417 */
1418 static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
1419 const char *device_name, void *data)
1420 {
1421 struct block_device *bdev = NULL;
1422 struct super_block *s;
1423 struct btrfs_fs_devices *fs_devices = NULL;
1424 struct btrfs_fs_info *fs_info = NULL;
1425 struct security_mnt_opts new_sec_opts;
1426 fmode_t mode = FMODE_READ;
1427 char *subvol_name = NULL;
1428 u64 subvol_objectid = 0;
1429 int error = 0;
1430
1431 if (!(flags & MS_RDONLY))
1432 mode |= FMODE_WRITE;
1433
1434 error = btrfs_parse_early_options(data, mode, fs_type,
1435 &subvol_name, &subvol_objectid,
1436 &fs_devices);
1437 if (error) {
1438 kfree(subvol_name);
1439 return ERR_PTR(error);
1440 }
1441
1442 if (subvol_name || subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
1443 /* mount_subvol() will free subvol_name. */
1444 return mount_subvol(subvol_name, subvol_objectid, flags,
1445 device_name, data);
1446 }
1447
1448 security_init_mnt_opts(&new_sec_opts);
1449 if (data) {
1450 error = parse_security_options(data, &new_sec_opts);
1451 if (error)
1452 return ERR_PTR(error);
1453 }
1454
1455 error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices);
1456 if (error)
1457 goto error_sec_opts;
1458
1459 /*
1460 * Setup a dummy root and fs_info for test/set super. This is because
1461 * we don't actually fill this stuff out until open_ctree, but we need
1462 * it for searching for existing supers, so this lets us do that and
1463 * then open_ctree will properly initialize everything later.
1464 */
1465 fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_NOFS);
1466 if (!fs_info) {
1467 error = -ENOMEM;
1468 goto error_sec_opts;
1469 }
1470
1471 fs_info->fs_devices = fs_devices;
1472
1473 fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
1474 fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
1475 security_init_mnt_opts(&fs_info->security_opts);
1476 if (!fs_info->super_copy || !fs_info->super_for_commit) {
1477 error = -ENOMEM;
1478 goto error_fs_info;
1479 }
1480
1481 error = btrfs_open_devices(fs_devices, mode, fs_type);
1482 if (error)
1483 goto error_fs_info;
1484
1485 if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
1486 error = -EACCES;
1487 goto error_close_devices;
1488 }
1489
1490 bdev = fs_devices->latest_bdev;
1491 s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | MS_NOSEC,
1492 fs_info);
1493 if (IS_ERR(s)) {
1494 error = PTR_ERR(s);
1495 goto error_close_devices;
1496 }
1497
1498 if (s->s_root) {
1499 btrfs_close_devices(fs_devices);
1500 free_fs_info(fs_info);
1501 if ((flags ^ s->s_flags) & MS_RDONLY)
1502 error = -EBUSY;
1503 } else {
1504 char b[BDEVNAME_SIZE];
1505
1506 strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
1507 btrfs_sb(s)->bdev_holder = fs_type;
1508 error = btrfs_fill_super(s, fs_devices, data,
1509 flags & MS_SILENT ? 1 : 0);
1510 }
1511 if (error) {
1512 deactivate_locked_super(s);
1513 goto error_sec_opts;
1514 }
1515
1516 fs_info = btrfs_sb(s);
1517 error = setup_security_options(fs_info, s, &new_sec_opts);
1518 if (error) {
1519 deactivate_locked_super(s);
1520 goto error_sec_opts;
1521 }
1522
1523 return dget(s->s_root);
1524
1525 error_close_devices:
1526 btrfs_close_devices(fs_devices);
1527 error_fs_info:
1528 free_fs_info(fs_info);
1529 error_sec_opts:
1530 security_free_mnt_opts(&new_sec_opts);
1531 return ERR_PTR(error);
1532 }
1533
1534 static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
1535 int new_pool_size, int old_pool_size)
1536 {
1537 if (new_pool_size == old_pool_size)
1538 return;
1539
1540 fs_info->thread_pool_size = new_pool_size;
1541
1542 btrfs_info(fs_info, "resize thread pool %d -> %d",
1543 old_pool_size, new_pool_size);
1544
1545 btrfs_workqueue_set_max(fs_info->workers, new_pool_size);
1546 btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size);
1547 btrfs_workqueue_set_max(fs_info->submit_workers, new_pool_size);
1548 btrfs_workqueue_set_max(fs_info->caching_workers, new_pool_size);
1549 btrfs_workqueue_set_max(fs_info->endio_workers, new_pool_size);
1550 btrfs_workqueue_set_max(fs_info->endio_meta_workers, new_pool_size);
1551 btrfs_workqueue_set_max(fs_info->endio_meta_write_workers,
1552 new_pool_size);
1553 btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size);
1554 btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
1555 btrfs_workqueue_set_max(fs_info->delayed_workers, new_pool_size);
1556 btrfs_workqueue_set_max(fs_info->readahead_workers, new_pool_size);
1557 btrfs_workqueue_set_max(fs_info->scrub_wr_completion_workers,
1558 new_pool_size);
1559 }
1560
1561 static inline void btrfs_remount_prepare(struct btrfs_fs_info *fs_info)
1562 {
1563 set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1564 }
1565
1566 static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info,
1567 unsigned long old_opts, int flags)
1568 {
1569 if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1570 (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1571 (flags & MS_RDONLY))) {
1572 /* wait for any defraggers to finish */
1573 wait_event(fs_info->transaction_wait,
1574 (atomic_read(&fs_info->defrag_running) == 0));
1575 if (flags & MS_RDONLY)
1576 sync_filesystem(fs_info->sb);
1577 }
1578 }
1579
1580 static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
1581 unsigned long old_opts)
1582 {
1583 /*
1584 * We need cleanup all defragable inodes if the autodefragment is
1585 * close or the fs is R/O.
1586 */
1587 if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1588 (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1589 (fs_info->sb->s_flags & MS_RDONLY))) {
1590 btrfs_cleanup_defrag_inodes(fs_info);
1591 }
1592
1593 clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1594 }
1595
1596 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
1597 {
1598 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1599 struct btrfs_root *root = fs_info->tree_root;
1600 unsigned old_flags = sb->s_flags;
1601 unsigned long old_opts = fs_info->mount_opt;
1602 unsigned long old_compress_type = fs_info->compress_type;
1603 u64 old_max_inline = fs_info->max_inline;
1604 u64 old_alloc_start = fs_info->alloc_start;
1605 int old_thread_pool_size = fs_info->thread_pool_size;
1606 unsigned int old_metadata_ratio = fs_info->metadata_ratio;
1607 int ret;
1608
1609 sync_filesystem(sb);
1610 btrfs_remount_prepare(fs_info);
1611
1612 if (data) {
1613 struct security_mnt_opts new_sec_opts;
1614
1615 security_init_mnt_opts(&new_sec_opts);
1616 ret = parse_security_options(data, &new_sec_opts);
1617 if (ret)
1618 goto restore;
1619 ret = setup_security_options(fs_info, sb,
1620 &new_sec_opts);
1621 if (ret) {
1622 security_free_mnt_opts(&new_sec_opts);
1623 goto restore;
1624 }
1625 }
1626
1627 ret = btrfs_parse_options(root, data);
1628 if (ret) {
1629 ret = -EINVAL;
1630 goto restore;
1631 }
1632
1633 btrfs_remount_begin(fs_info, old_opts, *flags);
1634 btrfs_resize_thread_pool(fs_info,
1635 fs_info->thread_pool_size, old_thread_pool_size);
1636
1637 if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1638 goto out;
1639
1640 if (*flags & MS_RDONLY) {
1641 /*
1642 * this also happens on 'umount -rf' or on shutdown, when
1643 * the filesystem is busy.
1644 */
1645 cancel_work_sync(&fs_info->async_reclaim_work);
1646
1647 /* wait for the uuid_scan task to finish */
1648 down(&fs_info->uuid_tree_rescan_sem);
1649 /* avoid complains from lockdep et al. */
1650 up(&fs_info->uuid_tree_rescan_sem);
1651
1652 sb->s_flags |= MS_RDONLY;
1653
1654 /*
1655 * Setting MS_RDONLY will put the cleaner thread to
1656 * sleep at the next loop if it's already active.
1657 * If it's already asleep, we'll leave unused block
1658 * groups on disk until we're mounted read-write again
1659 * unless we clean them up here.
1660 */
1661 btrfs_delete_unused_bgs(fs_info);
1662
1663 btrfs_dev_replace_suspend_for_unmount(fs_info);
1664 btrfs_scrub_cancel(fs_info);
1665 btrfs_pause_balance(fs_info);
1666
1667 ret = btrfs_commit_super(root);
1668 if (ret)
1669 goto restore;
1670 } else {
1671 if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state)) {
1672 btrfs_err(fs_info,
1673 "Remounting read-write after error is not allowed");
1674 ret = -EINVAL;
1675 goto restore;
1676 }
1677 if (fs_info->fs_devices->rw_devices == 0) {
1678 ret = -EACCES;
1679 goto restore;
1680 }
1681
1682 if (fs_info->fs_devices->missing_devices >
1683 fs_info->num_tolerated_disk_barrier_failures &&
1684 !(*flags & MS_RDONLY)) {
1685 btrfs_warn(fs_info,
1686 "too many missing devices, writeable remount is not allowed");
1687 ret = -EACCES;
1688 goto restore;
1689 }
1690
1691 if (btrfs_super_log_root(fs_info->super_copy) != 0) {
1692 ret = -EINVAL;
1693 goto restore;
1694 }
1695
1696 ret = btrfs_cleanup_fs_roots(fs_info);
1697 if (ret)
1698 goto restore;
1699
1700 /* recover relocation */
1701 mutex_lock(&fs_info->cleaner_mutex);
1702 ret = btrfs_recover_relocation(root);
1703 mutex_unlock(&fs_info->cleaner_mutex);
1704 if (ret)
1705 goto restore;
1706
1707 ret = btrfs_resume_balance_async(fs_info);
1708 if (ret)
1709 goto restore;
1710
1711 ret = btrfs_resume_dev_replace_async(fs_info);
1712 if (ret) {
1713 btrfs_warn(fs_info, "failed to resume dev_replace");
1714 goto restore;
1715 }
1716
1717 if (!fs_info->uuid_root) {
1718 btrfs_info(fs_info, "creating UUID tree");
1719 ret = btrfs_create_uuid_tree(fs_info);
1720 if (ret) {
1721 btrfs_warn(fs_info, "failed to create the UUID tree %d", ret);
1722 goto restore;
1723 }
1724 }
1725 sb->s_flags &= ~MS_RDONLY;
1726 }
1727 out:
1728 wake_up_process(fs_info->transaction_kthread);
1729 btrfs_remount_cleanup(fs_info, old_opts);
1730 return 0;
1731
1732 restore:
1733 /* We've hit an error - don't reset MS_RDONLY */
1734 if (sb->s_flags & MS_RDONLY)
1735 old_flags |= MS_RDONLY;
1736 sb->s_flags = old_flags;
1737 fs_info->mount_opt = old_opts;
1738 fs_info->compress_type = old_compress_type;
1739 fs_info->max_inline = old_max_inline;
1740 mutex_lock(&fs_info->chunk_mutex);
1741 fs_info->alloc_start = old_alloc_start;
1742 mutex_unlock(&fs_info->chunk_mutex);
1743 btrfs_resize_thread_pool(fs_info,
1744 old_thread_pool_size, fs_info->thread_pool_size);
1745 fs_info->metadata_ratio = old_metadata_ratio;
1746 btrfs_remount_cleanup(fs_info, old_opts);
1747 return ret;
1748 }
1749
1750 /* Used to sort the devices by max_avail(descending sort) */
1751 static int btrfs_cmp_device_free_bytes(const void *dev_info1,
1752 const void *dev_info2)
1753 {
1754 if (((struct btrfs_device_info *)dev_info1)->max_avail >
1755 ((struct btrfs_device_info *)dev_info2)->max_avail)
1756 return -1;
1757 else if (((struct btrfs_device_info *)dev_info1)->max_avail <
1758 ((struct btrfs_device_info *)dev_info2)->max_avail)
1759 return 1;
1760 else
1761 return 0;
1762 }
1763
1764 /*
1765 * sort the devices by max_avail, in which max free extent size of each device
1766 * is stored.(Descending Sort)
1767 */
1768 static inline void btrfs_descending_sort_devices(
1769 struct btrfs_device_info *devices,
1770 size_t nr_devices)
1771 {
1772 sort(devices, nr_devices, sizeof(struct btrfs_device_info),
1773 btrfs_cmp_device_free_bytes, NULL);
1774 }
1775
1776 /*
1777 * The helper to calc the free space on the devices that can be used to store
1778 * file data.
1779 */
1780 static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes)
1781 {
1782 struct btrfs_fs_info *fs_info = root->fs_info;
1783 struct btrfs_device_info *devices_info;
1784 struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
1785 struct btrfs_device *device;
1786 u64 skip_space;
1787 u64 type;
1788 u64 avail_space;
1789 u64 used_space;
1790 u64 min_stripe_size;
1791 int min_stripes = 1, num_stripes = 1;
1792 int i = 0, nr_devices;
1793 int ret;
1794
1795 /*
1796 * We aren't under the device list lock, so this is racey-ish, but good
1797 * enough for our purposes.
1798 */
1799 nr_devices = fs_info->fs_devices->open_devices;
1800 if (!nr_devices) {
1801 smp_mb();
1802 nr_devices = fs_info->fs_devices->open_devices;
1803 ASSERT(nr_devices);
1804 if (!nr_devices) {
1805 *free_bytes = 0;
1806 return 0;
1807 }
1808 }
1809
1810 devices_info = kmalloc_array(nr_devices, sizeof(*devices_info),
1811 GFP_NOFS);
1812 if (!devices_info)
1813 return -ENOMEM;
1814
1815 /* calc min stripe number for data space alloction */
1816 type = btrfs_get_alloc_profile(root, 1);
1817 if (type & BTRFS_BLOCK_GROUP_RAID0) {
1818 min_stripes = 2;
1819 num_stripes = nr_devices;
1820 } else if (type & BTRFS_BLOCK_GROUP_RAID1) {
1821 min_stripes = 2;
1822 num_stripes = 2;
1823 } else if (type & BTRFS_BLOCK_GROUP_RAID10) {
1824 min_stripes = 4;
1825 num_stripes = 4;
1826 }
1827
1828 if (type & BTRFS_BLOCK_GROUP_DUP)
1829 min_stripe_size = 2 * BTRFS_STRIPE_LEN;
1830 else
1831 min_stripe_size = BTRFS_STRIPE_LEN;
1832
1833 if (fs_info->alloc_start)
1834 mutex_lock(&fs_devices->device_list_mutex);
1835 rcu_read_lock();
1836 list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
1837 if (!device->in_fs_metadata || !device->bdev ||
1838 device->is_tgtdev_for_dev_replace)
1839 continue;
1840
1841 if (i >= nr_devices)
1842 break;
1843
1844 avail_space = device->total_bytes - device->bytes_used;
1845
1846 /* align with stripe_len */
1847 avail_space = div_u64(avail_space, BTRFS_STRIPE_LEN);
1848 avail_space *= BTRFS_STRIPE_LEN;
1849
1850 /*
1851 * In order to avoid overwritting the superblock on the drive,
1852 * btrfs starts at an offset of at least 1MB when doing chunk
1853 * allocation.
1854 */
1855 skip_space = 1024 * 1024;
1856
1857 /* user can set the offset in fs_info->alloc_start. */
1858 if (fs_info->alloc_start &&
1859 fs_info->alloc_start + BTRFS_STRIPE_LEN <=
1860 device->total_bytes) {
1861 rcu_read_unlock();
1862 skip_space = max(fs_info->alloc_start, skip_space);
1863
1864 /*
1865 * btrfs can not use the free space in
1866 * [0, skip_space - 1], we must subtract it from the
1867 * total. In order to implement it, we account the used
1868 * space in this range first.
1869 */
1870 ret = btrfs_account_dev_extents_size(device, 0,
1871 skip_space - 1,
1872 &used_space);
1873 if (ret) {
1874 kfree(devices_info);
1875 mutex_unlock(&fs_devices->device_list_mutex);
1876 return ret;
1877 }
1878
1879 rcu_read_lock();
1880
1881 /* calc the free space in [0, skip_space - 1] */
1882 skip_space -= used_space;
1883 }
1884
1885 /*
1886 * we can use the free space in [0, skip_space - 1], subtract
1887 * it from the total.
1888 */
1889 if (avail_space && avail_space >= skip_space)
1890 avail_space -= skip_space;
1891 else
1892 avail_space = 0;
1893
1894 if (avail_space < min_stripe_size)
1895 continue;
1896
1897 devices_info[i].dev = device;
1898 devices_info[i].max_avail = avail_space;
1899
1900 i++;
1901 }
1902 rcu_read_unlock();
1903 if (fs_info->alloc_start)
1904 mutex_unlock(&fs_devices->device_list_mutex);
1905
1906 nr_devices = i;
1907
1908 btrfs_descending_sort_devices(devices_info, nr_devices);
1909
1910 i = nr_devices - 1;
1911 avail_space = 0;
1912 while (nr_devices >= min_stripes) {
1913 if (num_stripes > nr_devices)
1914 num_stripes = nr_devices;
1915
1916 if (devices_info[i].max_avail >= min_stripe_size) {
1917 int j;
1918 u64 alloc_size;
1919
1920 avail_space += devices_info[i].max_avail * num_stripes;
1921 alloc_size = devices_info[i].max_avail;
1922 for (j = i + 1 - num_stripes; j <= i; j++)
1923 devices_info[j].max_avail -= alloc_size;
1924 }
1925 i--;
1926 nr_devices--;
1927 }
1928
1929 kfree(devices_info);
1930 *free_bytes = avail_space;
1931 return 0;
1932 }
1933
1934 /*
1935 * Calculate numbers for 'df', pessimistic in case of mixed raid profiles.
1936 *
1937 * If there's a redundant raid level at DATA block groups, use the respective
1938 * multiplier to scale the sizes.
1939 *
1940 * Unused device space usage is based on simulating the chunk allocator
1941 * algorithm that respects the device sizes, order of allocations and the
1942 * 'alloc_start' value, this is a close approximation of the actual use but
1943 * there are other factors that may change the result (like a new metadata
1944 * chunk).
1945 *
1946 * FIXME: not accurate for mixed block groups, total and free/used are ok,
1947 * available appears slightly larger.
1948 */
1949 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
1950 {
1951 struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
1952 struct btrfs_super_block *disk_super = fs_info->super_copy;
1953 struct list_head *head = &fs_info->space_info;
1954 struct btrfs_space_info *found;
1955 u64 total_used = 0;
1956 u64 total_free_data = 0;
1957 int bits = dentry->d_sb->s_blocksize_bits;
1958 __be32 *fsid = (__be32 *)fs_info->fsid;
1959 unsigned factor = 1;
1960 struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
1961 int ret;
1962
1963 /*
1964 * holding chunk_muext to avoid allocating new chunks, holding
1965 * device_list_mutex to avoid the device being removed
1966 */
1967 rcu_read_lock();
1968 list_for_each_entry_rcu(found, head, list) {
1969 if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
1970 int i;
1971
1972 total_free_data += found->disk_total - found->disk_used;
1973 total_free_data -=
1974 btrfs_account_ro_block_groups_free_space(found);
1975
1976 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
1977 if (!list_empty(&found->block_groups[i])) {
1978 switch (i) {
1979 case BTRFS_RAID_DUP:
1980 case BTRFS_RAID_RAID1:
1981 case BTRFS_RAID_RAID10:
1982 factor = 2;
1983 }
1984 }
1985 }
1986 }
1987
1988 total_used += found->disk_used;
1989 }
1990
1991 rcu_read_unlock();
1992
1993 buf->f_blocks = div_u64(btrfs_super_total_bytes(disk_super), factor);
1994 buf->f_blocks >>= bits;
1995 buf->f_bfree = buf->f_blocks - (div_u64(total_used, factor) >> bits);
1996
1997 /* Account global block reserve as used, it's in logical size already */
1998 spin_lock(&block_rsv->lock);
1999 buf->f_bfree -= block_rsv->size >> bits;
2000 spin_unlock(&block_rsv->lock);
2001
2002 buf->f_bavail = div_u64(total_free_data, factor);
2003 ret = btrfs_calc_avail_data_space(fs_info->tree_root, &total_free_data);
2004 if (ret)
2005 return ret;
2006 buf->f_bavail += div_u64(total_free_data, factor);
2007 buf->f_bavail = buf->f_bavail >> bits;
2008
2009 buf->f_type = BTRFS_SUPER_MAGIC;
2010 buf->f_bsize = dentry->d_sb->s_blocksize;
2011 buf->f_namelen = BTRFS_NAME_LEN;
2012
2013 /* We treat it as constant endianness (it doesn't matter _which_)
2014 because we want the fsid to come out the same whether mounted
2015 on a big-endian or little-endian host */
2016 buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
2017 buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
2018 /* Mask in the root object ID too, to disambiguate subvols */
2019 buf->f_fsid.val[0] ^= BTRFS_I(d_inode(dentry))->root->objectid >> 32;
2020 buf->f_fsid.val[1] ^= BTRFS_I(d_inode(dentry))->root->objectid;
2021
2022 return 0;
2023 }
2024
2025 static void btrfs_kill_super(struct super_block *sb)
2026 {
2027 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2028 kill_anon_super(sb);
2029 free_fs_info(fs_info);
2030 }
2031
2032 static struct file_system_type btrfs_fs_type = {
2033 .owner = THIS_MODULE,
2034 .name = "btrfs",
2035 .mount = btrfs_mount,
2036 .kill_sb = btrfs_kill_super,
2037 .fs_flags = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,
2038 };
2039 MODULE_ALIAS_FS("btrfs");
2040
2041 static int btrfs_control_open(struct inode *inode, struct file *file)
2042 {
2043 /*
2044 * The control file's private_data is used to hold the
2045 * transaction when it is started and is used to keep
2046 * track of whether a transaction is already in progress.
2047 */
2048 file->private_data = NULL;
2049 return 0;
2050 }
2051
2052 /*
2053 * used by btrfsctl to scan devices when no FS is mounted
2054 */
2055 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
2056 unsigned long arg)
2057 {
2058 struct btrfs_ioctl_vol_args *vol;
2059 struct btrfs_fs_devices *fs_devices;
2060 int ret = -ENOTTY;
2061
2062 if (!capable(CAP_SYS_ADMIN))
2063 return -EPERM;
2064
2065 vol = memdup_user((void __user *)arg, sizeof(*vol));
2066 if (IS_ERR(vol))
2067 return PTR_ERR(vol);
2068
2069 switch (cmd) {
2070 case BTRFS_IOC_SCAN_DEV:
2071 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
2072 &btrfs_fs_type, &fs_devices);
2073 break;
2074 case BTRFS_IOC_DEVICES_READY:
2075 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
2076 &btrfs_fs_type, &fs_devices);
2077 if (ret)
2078 break;
2079 ret = !(fs_devices->num_devices == fs_devices->total_devices);
2080 break;
2081 }
2082
2083 kfree(vol);
2084 return ret;
2085 }
2086
2087 static int btrfs_freeze(struct super_block *sb)
2088 {
2089 struct btrfs_trans_handle *trans;
2090 struct btrfs_root *root = btrfs_sb(sb)->tree_root;
2091
2092 trans = btrfs_attach_transaction_barrier(root);
2093 if (IS_ERR(trans)) {
2094 /* no transaction, don't bother */
2095 if (PTR_ERR(trans) == -ENOENT)
2096 return 0;
2097 return PTR_ERR(trans);
2098 }
2099 return btrfs_commit_transaction(trans, root);
2100 }
2101
2102 static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
2103 {
2104 struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
2105 struct btrfs_fs_devices *cur_devices;
2106 struct btrfs_device *dev, *first_dev = NULL;
2107 struct list_head *head;
2108 struct rcu_string *name;
2109
2110 mutex_lock(&fs_info->fs_devices->device_list_mutex);
2111 cur_devices = fs_info->fs_devices;
2112 while (cur_devices) {
2113 head = &cur_devices->devices;
2114 list_for_each_entry(dev, head, dev_list) {
2115 if (dev->missing)
2116 continue;
2117 if (!dev->name)
2118 continue;
2119 if (!first_dev || dev->devid < first_dev->devid)
2120 first_dev = dev;
2121 }
2122 cur_devices = cur_devices->seed;
2123 }
2124
2125 if (first_dev) {
2126 rcu_read_lock();
2127 name = rcu_dereference(first_dev->name);
2128 seq_escape(m, name->str, " \t\n\\");
2129 rcu_read_unlock();
2130 } else {
2131 WARN_ON(1);
2132 }
2133 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2134 return 0;
2135 }
2136
2137 static const struct super_operations btrfs_super_ops = {
2138 .drop_inode = btrfs_drop_inode,
2139 .evict_inode = btrfs_evict_inode,
2140 .put_super = btrfs_put_super,
2141 .sync_fs = btrfs_sync_fs,
2142 .show_options = btrfs_show_options,
2143 .show_devname = btrfs_show_devname,
2144 .write_inode = btrfs_write_inode,
2145 .alloc_inode = btrfs_alloc_inode,
2146 .destroy_inode = btrfs_destroy_inode,
2147 .statfs = btrfs_statfs,
2148 .remount_fs = btrfs_remount,
2149 .freeze_fs = btrfs_freeze,
2150 };
2151
2152 static const struct file_operations btrfs_ctl_fops = {
2153 .open = btrfs_control_open,
2154 .unlocked_ioctl = btrfs_control_ioctl,
2155 .compat_ioctl = btrfs_control_ioctl,
2156 .owner = THIS_MODULE,
2157 .llseek = noop_llseek,
2158 };
2159
2160 static struct miscdevice btrfs_misc = {
2161 .minor = BTRFS_MINOR,
2162 .name = "btrfs-control",
2163 .fops = &btrfs_ctl_fops
2164 };
2165
2166 MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
2167 MODULE_ALIAS("devname:btrfs-control");
2168
2169 static int btrfs_interface_init(void)
2170 {
2171 return misc_register(&btrfs_misc);
2172 }
2173
2174 static void btrfs_interface_exit(void)
2175 {
2176 misc_deregister(&btrfs_misc);
2177 }
2178
2179 static void btrfs_print_info(void)
2180 {
2181 printk(KERN_INFO "Btrfs loaded"
2182 #ifdef CONFIG_BTRFS_DEBUG
2183 ", debug=on"
2184 #endif
2185 #ifdef CONFIG_BTRFS_ASSERT
2186 ", assert=on"
2187 #endif
2188 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
2189 ", integrity-checker=on"
2190 #endif
2191 "\n");
2192 }
2193
2194 static int btrfs_run_sanity_tests(void)
2195 {
2196 int ret;
2197
2198 ret = btrfs_init_test_fs();
2199 if (ret)
2200 return ret;
2201
2202 ret = btrfs_test_free_space_cache();
2203 if (ret)
2204 goto out;
2205 ret = btrfs_test_extent_buffer_operations();
2206 if (ret)
2207 goto out;
2208 ret = btrfs_test_extent_io();
2209 if (ret)
2210 goto out;
2211 ret = btrfs_test_inodes();
2212 if (ret)
2213 goto out;
2214 ret = btrfs_test_qgroups();
2215 out:
2216 btrfs_destroy_test_fs();
2217 return ret;
2218 }
2219
2220 static int __init init_btrfs_fs(void)
2221 {
2222 int err;
2223
2224 err = btrfs_hash_init();
2225 if (err)
2226 return err;
2227
2228 btrfs_props_init();
2229
2230 err = btrfs_init_sysfs();
2231 if (err)
2232 goto free_hash;
2233
2234 btrfs_init_compress();
2235
2236 err = btrfs_init_cachep();
2237 if (err)
2238 goto free_compress;
2239
2240 err = extent_io_init();
2241 if (err)
2242 goto free_cachep;
2243
2244 err = extent_map_init();
2245 if (err)
2246 goto free_extent_io;
2247
2248 err = ordered_data_init();
2249 if (err)
2250 goto free_extent_map;
2251
2252 err = btrfs_delayed_inode_init();
2253 if (err)
2254 goto free_ordered_data;
2255
2256 err = btrfs_auto_defrag_init();
2257 if (err)
2258 goto free_delayed_inode;
2259
2260 err = btrfs_delayed_ref_init();
2261 if (err)
2262 goto free_auto_defrag;
2263
2264 err = btrfs_prelim_ref_init();
2265 if (err)
2266 goto free_delayed_ref;
2267
2268 err = btrfs_end_io_wq_init();
2269 if (err)
2270 goto free_prelim_ref;
2271
2272 err = btrfs_interface_init();
2273 if (err)
2274 goto free_end_io_wq;
2275
2276 btrfs_init_lockdep();
2277
2278 btrfs_print_info();
2279
2280 err = btrfs_run_sanity_tests();
2281 if (err)
2282 goto unregister_ioctl;
2283
2284 err = register_filesystem(&btrfs_fs_type);
2285 if (err)
2286 goto unregister_ioctl;
2287
2288 return 0;
2289
2290 unregister_ioctl:
2291 btrfs_interface_exit();
2292 free_end_io_wq:
2293 btrfs_end_io_wq_exit();
2294 free_prelim_ref:
2295 btrfs_prelim_ref_exit();
2296 free_delayed_ref:
2297 btrfs_delayed_ref_exit();
2298 free_auto_defrag:
2299 btrfs_auto_defrag_exit();
2300 free_delayed_inode:
2301 btrfs_delayed_inode_exit();
2302 free_ordered_data:
2303 ordered_data_exit();
2304 free_extent_map:
2305 extent_map_exit();
2306 free_extent_io:
2307 extent_io_exit();
2308 free_cachep:
2309 btrfs_destroy_cachep();
2310 free_compress:
2311 btrfs_exit_compress();
2312 btrfs_exit_sysfs();
2313 free_hash:
2314 btrfs_hash_exit();
2315 return err;
2316 }
2317
2318 static void __exit exit_btrfs_fs(void)
2319 {
2320 btrfs_destroy_cachep();
2321 btrfs_delayed_ref_exit();
2322 btrfs_auto_defrag_exit();
2323 btrfs_delayed_inode_exit();
2324 btrfs_prelim_ref_exit();
2325 ordered_data_exit();
2326 extent_map_exit();
2327 extent_io_exit();
2328 btrfs_interface_exit();
2329 btrfs_end_io_wq_exit();
2330 unregister_filesystem(&btrfs_fs_type);
2331 btrfs_exit_sysfs();
2332 btrfs_cleanup_fs_uuids();
2333 btrfs_exit_compress();
2334 btrfs_hash_exit();
2335 }
2336
2337 late_initcall(init_btrfs_fs);
2338 module_exit(exit_btrfs_fs)
2339
2340 MODULE_LICENSE("GPL");