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Merge tag 'iwlwifi-for-kalle-2016-02-25' of https://git.kernel.org/pub/scm/linux...
[deliverable/linux.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 /*
134 * __btrfs_std_error decodes expected errors from the caller and
135 * invokes the approciate error response.
136 */
137 __cold
138 void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function,
139 unsigned int line, int errno, const char *fmt, ...)
140 {
141 struct super_block *sb = fs_info->sb;
142 #ifdef CONFIG_PRINTK
143 const char *errstr;
144 #endif
145
146 /*
147 * Special case: if the error is EROFS, and we're already
148 * under MS_RDONLY, then it is safe here.
149 */
150 if (errno == -EROFS && (sb->s_flags & MS_RDONLY))
151 return;
152
153 #ifdef CONFIG_PRINTK
154 errstr = btrfs_decode_error(errno);
155 if (fmt) {
156 struct va_format vaf;
157 va_list args;
158
159 va_start(args, fmt);
160 vaf.fmt = fmt;
161 vaf.va = &args;
162
163 printk(KERN_CRIT
164 "BTRFS: error (device %s) in %s:%d: errno=%d %s (%pV)\n",
165 sb->s_id, function, line, errno, errstr, &vaf);
166 va_end(args);
167 } else {
168 printk(KERN_CRIT "BTRFS: error (device %s) in %s:%d: errno=%d %s\n",
169 sb->s_id, function, line, errno, errstr);
170 }
171 #endif
172
173 /* Don't go through full error handling during mount */
174 save_error_info(fs_info);
175 if (sb->s_flags & MS_BORN)
176 btrfs_handle_error(fs_info);
177 }
178
179 #ifdef CONFIG_PRINTK
180 static const char * const logtypes[] = {
181 "emergency",
182 "alert",
183 "critical",
184 "error",
185 "warning",
186 "notice",
187 "info",
188 "debug",
189 };
190
191 void btrfs_printk(const struct btrfs_fs_info *fs_info, const char *fmt, ...)
192 {
193 struct super_block *sb = fs_info->sb;
194 char lvl[4];
195 struct va_format vaf;
196 va_list args;
197 const char *type = logtypes[4];
198 int kern_level;
199
200 va_start(args, fmt);
201
202 kern_level = printk_get_level(fmt);
203 if (kern_level) {
204 size_t size = printk_skip_level(fmt) - fmt;
205 memcpy(lvl, fmt, size);
206 lvl[size] = '\0';
207 fmt += size;
208 type = logtypes[kern_level - '0'];
209 } else
210 *lvl = '\0';
211
212 vaf.fmt = fmt;
213 vaf.va = &args;
214
215 printk("%sBTRFS %s (device %s): %pV\n", lvl, type, sb->s_id, &vaf);
216
217 va_end(args);
218 }
219 #endif
220
221 /*
222 * We only mark the transaction aborted and then set the file system read-only.
223 * This will prevent new transactions from starting or trying to join this
224 * one.
225 *
226 * This means that error recovery at the call site is limited to freeing
227 * any local memory allocations and passing the error code up without
228 * further cleanup. The transaction should complete as it normally would
229 * in the call path but will return -EIO.
230 *
231 * We'll complete the cleanup in btrfs_end_transaction and
232 * btrfs_commit_transaction.
233 */
234 __cold
235 void __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
236 struct btrfs_root *root, const char *function,
237 unsigned int line, int errno)
238 {
239 trans->aborted = errno;
240 /* Nothing used. The other threads that have joined this
241 * transaction may be able to continue. */
242 if (!trans->blocks_used && list_empty(&trans->new_bgs)) {
243 const char *errstr;
244
245 errstr = btrfs_decode_error(errno);
246 btrfs_warn(root->fs_info,
247 "%s:%d: Aborting unused transaction(%s).",
248 function, line, errstr);
249 return;
250 }
251 ACCESS_ONCE(trans->transaction->aborted) = errno;
252 /* Wake up anybody who may be waiting on this transaction */
253 wake_up(&root->fs_info->transaction_wait);
254 wake_up(&root->fs_info->transaction_blocked_wait);
255 __btrfs_std_error(root->fs_info, function, line, errno, NULL);
256 }
257 /*
258 * __btrfs_panic decodes unexpected, fatal errors from the caller,
259 * issues an alert, and either panics or BUGs, depending on mount options.
260 */
261 __cold
262 void __btrfs_panic(struct btrfs_fs_info *fs_info, const char *function,
263 unsigned int line, int errno, const char *fmt, ...)
264 {
265 char *s_id = "<unknown>";
266 const char *errstr;
267 struct va_format vaf = { .fmt = fmt };
268 va_list args;
269
270 if (fs_info)
271 s_id = fs_info->sb->s_id;
272
273 va_start(args, fmt);
274 vaf.va = &args;
275
276 errstr = btrfs_decode_error(errno);
277 if (fs_info && (fs_info->mount_opt & BTRFS_MOUNT_PANIC_ON_FATAL_ERROR))
278 panic(KERN_CRIT "BTRFS panic (device %s) in %s:%d: %pV (errno=%d %s)\n",
279 s_id, function, line, &vaf, errno, errstr);
280
281 btrfs_crit(fs_info, "panic in %s:%d: %pV (errno=%d %s)",
282 function, line, &vaf, errno, errstr);
283 va_end(args);
284 /* Caller calls BUG() */
285 }
286
287 static void btrfs_put_super(struct super_block *sb)
288 {
289 close_ctree(btrfs_sb(sb)->tree_root);
290 }
291
292 enum {
293 Opt_degraded, Opt_subvol, Opt_subvolid, Opt_device, Opt_nodatasum,
294 Opt_nodatacow, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd,
295 Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl, Opt_compress,
296 Opt_compress_type, Opt_compress_force, Opt_compress_force_type,
297 Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard,
298 Opt_space_cache, Opt_space_cache_version, Opt_clear_cache,
299 Opt_user_subvol_rm_allowed, Opt_enospc_debug, Opt_subvolrootid,
300 Opt_defrag, Opt_inode_cache, Opt_no_space_cache, Opt_recovery,
301 Opt_skip_balance, Opt_check_integrity,
302 Opt_check_integrity_including_extent_data,
303 Opt_check_integrity_print_mask, Opt_fatal_errors, Opt_rescan_uuid_tree,
304 Opt_commit_interval, Opt_barrier, Opt_nodefrag, Opt_nodiscard,
305 Opt_noenospc_debug, Opt_noflushoncommit, Opt_acl, Opt_datacow,
306 Opt_datasum, Opt_treelog, Opt_noinode_cache,
307 #ifdef CONFIG_BTRFS_DEBUG
308 Opt_fragment_data, Opt_fragment_metadata, Opt_fragment_all,
309 #endif
310 Opt_err,
311 };
312
313 static const match_table_t tokens = {
314 {Opt_degraded, "degraded"},
315 {Opt_subvol, "subvol=%s"},
316 {Opt_subvolid, "subvolid=%s"},
317 {Opt_device, "device=%s"},
318 {Opt_nodatasum, "nodatasum"},
319 {Opt_datasum, "datasum"},
320 {Opt_nodatacow, "nodatacow"},
321 {Opt_datacow, "datacow"},
322 {Opt_nobarrier, "nobarrier"},
323 {Opt_barrier, "barrier"},
324 {Opt_max_inline, "max_inline=%s"},
325 {Opt_alloc_start, "alloc_start=%s"},
326 {Opt_thread_pool, "thread_pool=%d"},
327 {Opt_compress, "compress"},
328 {Opt_compress_type, "compress=%s"},
329 {Opt_compress_force, "compress-force"},
330 {Opt_compress_force_type, "compress-force=%s"},
331 {Opt_ssd, "ssd"},
332 {Opt_ssd_spread, "ssd_spread"},
333 {Opt_nossd, "nossd"},
334 {Opt_acl, "acl"},
335 {Opt_noacl, "noacl"},
336 {Opt_notreelog, "notreelog"},
337 {Opt_treelog, "treelog"},
338 {Opt_flushoncommit, "flushoncommit"},
339 {Opt_noflushoncommit, "noflushoncommit"},
340 {Opt_ratio, "metadata_ratio=%d"},
341 {Opt_discard, "discard"},
342 {Opt_nodiscard, "nodiscard"},
343 {Opt_space_cache, "space_cache"},
344 {Opt_space_cache_version, "space_cache=%s"},
345 {Opt_clear_cache, "clear_cache"},
346 {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
347 {Opt_enospc_debug, "enospc_debug"},
348 {Opt_noenospc_debug, "noenospc_debug"},
349 {Opt_subvolrootid, "subvolrootid=%d"},
350 {Opt_defrag, "autodefrag"},
351 {Opt_nodefrag, "noautodefrag"},
352 {Opt_inode_cache, "inode_cache"},
353 {Opt_noinode_cache, "noinode_cache"},
354 {Opt_no_space_cache, "nospace_cache"},
355 {Opt_recovery, "recovery"},
356 {Opt_skip_balance, "skip_balance"},
357 {Opt_check_integrity, "check_int"},
358 {Opt_check_integrity_including_extent_data, "check_int_data"},
359 {Opt_check_integrity_print_mask, "check_int_print_mask=%d"},
360 {Opt_rescan_uuid_tree, "rescan_uuid_tree"},
361 {Opt_fatal_errors, "fatal_errors=%s"},
362 {Opt_commit_interval, "commit=%d"},
363 #ifdef CONFIG_BTRFS_DEBUG
364 {Opt_fragment_data, "fragment=data"},
365 {Opt_fragment_metadata, "fragment=metadata"},
366 {Opt_fragment_all, "fragment=all"},
367 #endif
368 {Opt_err, NULL},
369 };
370
371 /*
372 * Regular mount options parser. Everything that is needed only when
373 * reading in a new superblock is parsed here.
374 * XXX JDM: This needs to be cleaned up for remount.
375 */
376 int btrfs_parse_options(struct btrfs_root *root, char *options)
377 {
378 struct btrfs_fs_info *info = root->fs_info;
379 substring_t args[MAX_OPT_ARGS];
380 char *p, *num, *orig = NULL;
381 u64 cache_gen;
382 int intarg;
383 int ret = 0;
384 char *compress_type;
385 bool compress_force = false;
386
387 cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
388 if (btrfs_fs_compat_ro(root->fs_info, FREE_SPACE_TREE))
389 btrfs_set_opt(info->mount_opt, FREE_SPACE_TREE);
390 else if (cache_gen)
391 btrfs_set_opt(info->mount_opt, SPACE_CACHE);
392
393 if (!options)
394 goto out;
395
396 /*
397 * strsep changes the string, duplicate it because parse_options
398 * gets called twice
399 */
400 options = kstrdup(options, GFP_NOFS);
401 if (!options)
402 return -ENOMEM;
403
404 orig = options;
405
406 while ((p = strsep(&options, ",")) != NULL) {
407 int token;
408 if (!*p)
409 continue;
410
411 token = match_token(p, tokens, args);
412 switch (token) {
413 case Opt_degraded:
414 btrfs_info(root->fs_info, "allowing degraded mounts");
415 btrfs_set_opt(info->mount_opt, DEGRADED);
416 break;
417 case Opt_subvol:
418 case Opt_subvolid:
419 case Opt_subvolrootid:
420 case Opt_device:
421 /*
422 * These are parsed by btrfs_parse_early_options
423 * and can be happily ignored here.
424 */
425 break;
426 case Opt_nodatasum:
427 btrfs_set_and_info(root, NODATASUM,
428 "setting nodatasum");
429 break;
430 case Opt_datasum:
431 if (btrfs_test_opt(root, NODATASUM)) {
432 if (btrfs_test_opt(root, NODATACOW))
433 btrfs_info(root->fs_info, "setting datasum, datacow enabled");
434 else
435 btrfs_info(root->fs_info, "setting datasum");
436 }
437 btrfs_clear_opt(info->mount_opt, NODATACOW);
438 btrfs_clear_opt(info->mount_opt, NODATASUM);
439 break;
440 case Opt_nodatacow:
441 if (!btrfs_test_opt(root, NODATACOW)) {
442 if (!btrfs_test_opt(root, COMPRESS) ||
443 !btrfs_test_opt(root, FORCE_COMPRESS)) {
444 btrfs_info(root->fs_info,
445 "setting nodatacow, compression disabled");
446 } else {
447 btrfs_info(root->fs_info, "setting nodatacow");
448 }
449 }
450 btrfs_clear_opt(info->mount_opt, COMPRESS);
451 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
452 btrfs_set_opt(info->mount_opt, NODATACOW);
453 btrfs_set_opt(info->mount_opt, NODATASUM);
454 break;
455 case Opt_datacow:
456 btrfs_clear_and_info(root, NODATACOW,
457 "setting datacow");
458 break;
459 case Opt_compress_force:
460 case Opt_compress_force_type:
461 compress_force = true;
462 /* Fallthrough */
463 case Opt_compress:
464 case Opt_compress_type:
465 if (token == Opt_compress ||
466 token == Opt_compress_force ||
467 strcmp(args[0].from, "zlib") == 0) {
468 compress_type = "zlib";
469 info->compress_type = BTRFS_COMPRESS_ZLIB;
470 btrfs_set_opt(info->mount_opt, COMPRESS);
471 btrfs_clear_opt(info->mount_opt, NODATACOW);
472 btrfs_clear_opt(info->mount_opt, NODATASUM);
473 } else if (strcmp(args[0].from, "lzo") == 0) {
474 compress_type = "lzo";
475 info->compress_type = BTRFS_COMPRESS_LZO;
476 btrfs_set_opt(info->mount_opt, COMPRESS);
477 btrfs_clear_opt(info->mount_opt, NODATACOW);
478 btrfs_clear_opt(info->mount_opt, NODATASUM);
479 btrfs_set_fs_incompat(info, COMPRESS_LZO);
480 } else if (strncmp(args[0].from, "no", 2) == 0) {
481 compress_type = "no";
482 btrfs_clear_opt(info->mount_opt, COMPRESS);
483 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
484 compress_force = false;
485 } else {
486 ret = -EINVAL;
487 goto out;
488 }
489
490 if (compress_force) {
491 btrfs_set_and_info(root, FORCE_COMPRESS,
492 "force %s compression",
493 compress_type);
494 } else {
495 if (!btrfs_test_opt(root, COMPRESS))
496 btrfs_info(root->fs_info,
497 "btrfs: use %s compression",
498 compress_type);
499 /*
500 * If we remount from compress-force=xxx to
501 * compress=xxx, we need clear FORCE_COMPRESS
502 * flag, otherwise, there is no way for users
503 * to disable forcible compression separately.
504 */
505 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
506 }
507 break;
508 case Opt_ssd:
509 btrfs_set_and_info(root, SSD,
510 "use ssd allocation scheme");
511 break;
512 case Opt_ssd_spread:
513 btrfs_set_and_info(root, SSD_SPREAD,
514 "use spread ssd allocation scheme");
515 btrfs_set_opt(info->mount_opt, SSD);
516 break;
517 case Opt_nossd:
518 btrfs_set_and_info(root, NOSSD,
519 "not using ssd allocation scheme");
520 btrfs_clear_opt(info->mount_opt, SSD);
521 break;
522 case Opt_barrier:
523 btrfs_clear_and_info(root, NOBARRIER,
524 "turning on barriers");
525 break;
526 case Opt_nobarrier:
527 btrfs_set_and_info(root, NOBARRIER,
528 "turning off barriers");
529 break;
530 case Opt_thread_pool:
531 ret = match_int(&args[0], &intarg);
532 if (ret) {
533 goto out;
534 } else if (intarg > 0) {
535 info->thread_pool_size = intarg;
536 } else {
537 ret = -EINVAL;
538 goto out;
539 }
540 break;
541 case Opt_max_inline:
542 num = match_strdup(&args[0]);
543 if (num) {
544 info->max_inline = memparse(num, NULL);
545 kfree(num);
546
547 if (info->max_inline) {
548 info->max_inline = min_t(u64,
549 info->max_inline,
550 root->sectorsize);
551 }
552 btrfs_info(root->fs_info, "max_inline at %llu",
553 info->max_inline);
554 } else {
555 ret = -ENOMEM;
556 goto out;
557 }
558 break;
559 case Opt_alloc_start:
560 num = match_strdup(&args[0]);
561 if (num) {
562 mutex_lock(&info->chunk_mutex);
563 info->alloc_start = memparse(num, NULL);
564 mutex_unlock(&info->chunk_mutex);
565 kfree(num);
566 btrfs_info(root->fs_info, "allocations start at %llu",
567 info->alloc_start);
568 } else {
569 ret = -ENOMEM;
570 goto out;
571 }
572 break;
573 case Opt_acl:
574 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
575 root->fs_info->sb->s_flags |= MS_POSIXACL;
576 break;
577 #else
578 btrfs_err(root->fs_info,
579 "support for ACL not compiled in!");
580 ret = -EINVAL;
581 goto out;
582 #endif
583 case Opt_noacl:
584 root->fs_info->sb->s_flags &= ~MS_POSIXACL;
585 break;
586 case Opt_notreelog:
587 btrfs_set_and_info(root, NOTREELOG,
588 "disabling tree log");
589 break;
590 case Opt_treelog:
591 btrfs_clear_and_info(root, NOTREELOG,
592 "enabling tree log");
593 break;
594 case Opt_flushoncommit:
595 btrfs_set_and_info(root, FLUSHONCOMMIT,
596 "turning on flush-on-commit");
597 break;
598 case Opt_noflushoncommit:
599 btrfs_clear_and_info(root, FLUSHONCOMMIT,
600 "turning off flush-on-commit");
601 break;
602 case Opt_ratio:
603 ret = match_int(&args[0], &intarg);
604 if (ret) {
605 goto out;
606 } else if (intarg >= 0) {
607 info->metadata_ratio = intarg;
608 btrfs_info(root->fs_info, "metadata ratio %d",
609 info->metadata_ratio);
610 } else {
611 ret = -EINVAL;
612 goto out;
613 }
614 break;
615 case Opt_discard:
616 btrfs_set_and_info(root, DISCARD,
617 "turning on discard");
618 break;
619 case Opt_nodiscard:
620 btrfs_clear_and_info(root, DISCARD,
621 "turning off discard");
622 break;
623 case Opt_space_cache:
624 case Opt_space_cache_version:
625 if (token == Opt_space_cache ||
626 strcmp(args[0].from, "v1") == 0) {
627 btrfs_clear_opt(root->fs_info->mount_opt,
628 FREE_SPACE_TREE);
629 btrfs_set_and_info(root, SPACE_CACHE,
630 "enabling disk space caching");
631 } else if (strcmp(args[0].from, "v2") == 0) {
632 btrfs_clear_opt(root->fs_info->mount_opt,
633 SPACE_CACHE);
634 btrfs_set_and_info(root, FREE_SPACE_TREE,
635 "enabling free space tree");
636 } else {
637 ret = -EINVAL;
638 goto out;
639 }
640 break;
641 case Opt_rescan_uuid_tree:
642 btrfs_set_opt(info->mount_opt, RESCAN_UUID_TREE);
643 break;
644 case Opt_no_space_cache:
645 if (btrfs_test_opt(root, SPACE_CACHE)) {
646 btrfs_clear_and_info(root, SPACE_CACHE,
647 "disabling disk space caching");
648 }
649 if (btrfs_test_opt(root, FREE_SPACE_TREE)) {
650 btrfs_clear_and_info(root, FREE_SPACE_TREE,
651 "disabling free space tree");
652 }
653 break;
654 case Opt_inode_cache:
655 btrfs_set_pending_and_info(info, INODE_MAP_CACHE,
656 "enabling inode map caching");
657 break;
658 case Opt_noinode_cache:
659 btrfs_clear_pending_and_info(info, INODE_MAP_CACHE,
660 "disabling inode map caching");
661 break;
662 case Opt_clear_cache:
663 btrfs_set_and_info(root, CLEAR_CACHE,
664 "force clearing of disk cache");
665 break;
666 case Opt_user_subvol_rm_allowed:
667 btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
668 break;
669 case Opt_enospc_debug:
670 btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
671 break;
672 case Opt_noenospc_debug:
673 btrfs_clear_opt(info->mount_opt, ENOSPC_DEBUG);
674 break;
675 case Opt_defrag:
676 btrfs_set_and_info(root, AUTO_DEFRAG,
677 "enabling auto defrag");
678 break;
679 case Opt_nodefrag:
680 btrfs_clear_and_info(root, AUTO_DEFRAG,
681 "disabling auto defrag");
682 break;
683 case Opt_recovery:
684 btrfs_info(root->fs_info, "enabling auto recovery");
685 btrfs_set_opt(info->mount_opt, RECOVERY);
686 break;
687 case Opt_skip_balance:
688 btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
689 break;
690 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
691 case Opt_check_integrity_including_extent_data:
692 btrfs_info(root->fs_info,
693 "enabling check integrity including extent data");
694 btrfs_set_opt(info->mount_opt,
695 CHECK_INTEGRITY_INCLUDING_EXTENT_DATA);
696 btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
697 break;
698 case Opt_check_integrity:
699 btrfs_info(root->fs_info, "enabling check integrity");
700 btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
701 break;
702 case Opt_check_integrity_print_mask:
703 ret = match_int(&args[0], &intarg);
704 if (ret) {
705 goto out;
706 } else if (intarg >= 0) {
707 info->check_integrity_print_mask = intarg;
708 btrfs_info(root->fs_info, "check_integrity_print_mask 0x%x",
709 info->check_integrity_print_mask);
710 } else {
711 ret = -EINVAL;
712 goto out;
713 }
714 break;
715 #else
716 case Opt_check_integrity_including_extent_data:
717 case Opt_check_integrity:
718 case Opt_check_integrity_print_mask:
719 btrfs_err(root->fs_info,
720 "support for check_integrity* not compiled in!");
721 ret = -EINVAL;
722 goto out;
723 #endif
724 case Opt_fatal_errors:
725 if (strcmp(args[0].from, "panic") == 0)
726 btrfs_set_opt(info->mount_opt,
727 PANIC_ON_FATAL_ERROR);
728 else if (strcmp(args[0].from, "bug") == 0)
729 btrfs_clear_opt(info->mount_opt,
730 PANIC_ON_FATAL_ERROR);
731 else {
732 ret = -EINVAL;
733 goto out;
734 }
735 break;
736 case Opt_commit_interval:
737 intarg = 0;
738 ret = match_int(&args[0], &intarg);
739 if (ret < 0) {
740 btrfs_err(root->fs_info, "invalid commit interval");
741 ret = -EINVAL;
742 goto out;
743 }
744 if (intarg > 0) {
745 if (intarg > 300) {
746 btrfs_warn(root->fs_info, "excessive commit interval %d",
747 intarg);
748 }
749 info->commit_interval = intarg;
750 } else {
751 btrfs_info(root->fs_info, "using default commit interval %ds",
752 BTRFS_DEFAULT_COMMIT_INTERVAL);
753 info->commit_interval = BTRFS_DEFAULT_COMMIT_INTERVAL;
754 }
755 break;
756 #ifdef CONFIG_BTRFS_DEBUG
757 case Opt_fragment_all:
758 btrfs_info(root->fs_info, "fragmenting all space");
759 btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
760 btrfs_set_opt(info->mount_opt, FRAGMENT_METADATA);
761 break;
762 case Opt_fragment_metadata:
763 btrfs_info(root->fs_info, "fragmenting metadata");
764 btrfs_set_opt(info->mount_opt,
765 FRAGMENT_METADATA);
766 break;
767 case Opt_fragment_data:
768 btrfs_info(root->fs_info, "fragmenting data");
769 btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
770 break;
771 #endif
772 case Opt_err:
773 btrfs_info(root->fs_info, "unrecognized mount option '%s'", p);
774 ret = -EINVAL;
775 goto out;
776 default:
777 break;
778 }
779 }
780 out:
781 if (btrfs_fs_compat_ro(root->fs_info, FREE_SPACE_TREE) &&
782 !btrfs_test_opt(root, FREE_SPACE_TREE) &&
783 !btrfs_test_opt(root, CLEAR_CACHE)) {
784 btrfs_err(root->fs_info, "cannot disable free space tree");
785 ret = -EINVAL;
786
787 }
788 if (!ret && btrfs_test_opt(root, SPACE_CACHE))
789 btrfs_info(root->fs_info, "disk space caching is enabled");
790 if (!ret && btrfs_test_opt(root, FREE_SPACE_TREE))
791 btrfs_info(root->fs_info, "using free space tree");
792 kfree(orig);
793 return ret;
794 }
795
796 /*
797 * Parse mount options that are required early in the mount process.
798 *
799 * All other options will be parsed on much later in the mount process and
800 * only when we need to allocate a new super block.
801 */
802 static int btrfs_parse_early_options(const char *options, fmode_t flags,
803 void *holder, char **subvol_name, u64 *subvol_objectid,
804 struct btrfs_fs_devices **fs_devices)
805 {
806 substring_t args[MAX_OPT_ARGS];
807 char *device_name, *opts, *orig, *p;
808 char *num = NULL;
809 int error = 0;
810
811 if (!options)
812 return 0;
813
814 /*
815 * strsep changes the string, duplicate it because parse_options
816 * gets called twice
817 */
818 opts = kstrdup(options, GFP_KERNEL);
819 if (!opts)
820 return -ENOMEM;
821 orig = opts;
822
823 while ((p = strsep(&opts, ",")) != NULL) {
824 int token;
825 if (!*p)
826 continue;
827
828 token = match_token(p, tokens, args);
829 switch (token) {
830 case Opt_subvol:
831 kfree(*subvol_name);
832 *subvol_name = match_strdup(&args[0]);
833 if (!*subvol_name) {
834 error = -ENOMEM;
835 goto out;
836 }
837 break;
838 case Opt_subvolid:
839 num = match_strdup(&args[0]);
840 if (num) {
841 *subvol_objectid = memparse(num, NULL);
842 kfree(num);
843 /* we want the original fs_tree */
844 if (!*subvol_objectid)
845 *subvol_objectid =
846 BTRFS_FS_TREE_OBJECTID;
847 } else {
848 error = -EINVAL;
849 goto out;
850 }
851 break;
852 case Opt_subvolrootid:
853 printk(KERN_WARNING
854 "BTRFS: 'subvolrootid' mount option is deprecated and has "
855 "no effect\n");
856 break;
857 case Opt_device:
858 device_name = match_strdup(&args[0]);
859 if (!device_name) {
860 error = -ENOMEM;
861 goto out;
862 }
863 error = btrfs_scan_one_device(device_name,
864 flags, holder, fs_devices);
865 kfree(device_name);
866 if (error)
867 goto out;
868 break;
869 default:
870 break;
871 }
872 }
873
874 out:
875 kfree(orig);
876 return error;
877 }
878
879 static char *get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
880 u64 subvol_objectid)
881 {
882 struct btrfs_root *root = fs_info->tree_root;
883 struct btrfs_root *fs_root;
884 struct btrfs_root_ref *root_ref;
885 struct btrfs_inode_ref *inode_ref;
886 struct btrfs_key key;
887 struct btrfs_path *path = NULL;
888 char *name = NULL, *ptr;
889 u64 dirid;
890 int len;
891 int ret;
892
893 path = btrfs_alloc_path();
894 if (!path) {
895 ret = -ENOMEM;
896 goto err;
897 }
898 path->leave_spinning = 1;
899
900 name = kmalloc(PATH_MAX, GFP_NOFS);
901 if (!name) {
902 ret = -ENOMEM;
903 goto err;
904 }
905 ptr = name + PATH_MAX - 1;
906 ptr[0] = '\0';
907
908 /*
909 * Walk up the subvolume trees in the tree of tree roots by root
910 * backrefs until we hit the top-level subvolume.
911 */
912 while (subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
913 key.objectid = subvol_objectid;
914 key.type = BTRFS_ROOT_BACKREF_KEY;
915 key.offset = (u64)-1;
916
917 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
918 if (ret < 0) {
919 goto err;
920 } else if (ret > 0) {
921 ret = btrfs_previous_item(root, path, subvol_objectid,
922 BTRFS_ROOT_BACKREF_KEY);
923 if (ret < 0) {
924 goto err;
925 } else if (ret > 0) {
926 ret = -ENOENT;
927 goto err;
928 }
929 }
930
931 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
932 subvol_objectid = key.offset;
933
934 root_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
935 struct btrfs_root_ref);
936 len = btrfs_root_ref_name_len(path->nodes[0], root_ref);
937 ptr -= len + 1;
938 if (ptr < name) {
939 ret = -ENAMETOOLONG;
940 goto err;
941 }
942 read_extent_buffer(path->nodes[0], ptr + 1,
943 (unsigned long)(root_ref + 1), len);
944 ptr[0] = '/';
945 dirid = btrfs_root_ref_dirid(path->nodes[0], root_ref);
946 btrfs_release_path(path);
947
948 key.objectid = subvol_objectid;
949 key.type = BTRFS_ROOT_ITEM_KEY;
950 key.offset = (u64)-1;
951 fs_root = btrfs_read_fs_root_no_name(fs_info, &key);
952 if (IS_ERR(fs_root)) {
953 ret = PTR_ERR(fs_root);
954 goto err;
955 }
956
957 /*
958 * Walk up the filesystem tree by inode refs until we hit the
959 * root directory.
960 */
961 while (dirid != BTRFS_FIRST_FREE_OBJECTID) {
962 key.objectid = dirid;
963 key.type = BTRFS_INODE_REF_KEY;
964 key.offset = (u64)-1;
965
966 ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0);
967 if (ret < 0) {
968 goto err;
969 } else if (ret > 0) {
970 ret = btrfs_previous_item(fs_root, path, dirid,
971 BTRFS_INODE_REF_KEY);
972 if (ret < 0) {
973 goto err;
974 } else if (ret > 0) {
975 ret = -ENOENT;
976 goto err;
977 }
978 }
979
980 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
981 dirid = key.offset;
982
983 inode_ref = btrfs_item_ptr(path->nodes[0],
984 path->slots[0],
985 struct btrfs_inode_ref);
986 len = btrfs_inode_ref_name_len(path->nodes[0],
987 inode_ref);
988 ptr -= len + 1;
989 if (ptr < name) {
990 ret = -ENAMETOOLONG;
991 goto err;
992 }
993 read_extent_buffer(path->nodes[0], ptr + 1,
994 (unsigned long)(inode_ref + 1), len);
995 ptr[0] = '/';
996 btrfs_release_path(path);
997 }
998 }
999
1000 btrfs_free_path(path);
1001 if (ptr == name + PATH_MAX - 1) {
1002 name[0] = '/';
1003 name[1] = '\0';
1004 } else {
1005 memmove(name, ptr, name + PATH_MAX - ptr);
1006 }
1007 return name;
1008
1009 err:
1010 btrfs_free_path(path);
1011 kfree(name);
1012 return ERR_PTR(ret);
1013 }
1014
1015 static int get_default_subvol_objectid(struct btrfs_fs_info *fs_info, u64 *objectid)
1016 {
1017 struct btrfs_root *root = fs_info->tree_root;
1018 struct btrfs_dir_item *di;
1019 struct btrfs_path *path;
1020 struct btrfs_key location;
1021 u64 dir_id;
1022
1023 path = btrfs_alloc_path();
1024 if (!path)
1025 return -ENOMEM;
1026 path->leave_spinning = 1;
1027
1028 /*
1029 * Find the "default" dir item which points to the root item that we
1030 * will mount by default if we haven't been given a specific subvolume
1031 * to mount.
1032 */
1033 dir_id = btrfs_super_root_dir(fs_info->super_copy);
1034 di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
1035 if (IS_ERR(di)) {
1036 btrfs_free_path(path);
1037 return PTR_ERR(di);
1038 }
1039 if (!di) {
1040 /*
1041 * Ok the default dir item isn't there. This is weird since
1042 * it's always been there, but don't freak out, just try and
1043 * mount the top-level subvolume.
1044 */
1045 btrfs_free_path(path);
1046 *objectid = BTRFS_FS_TREE_OBJECTID;
1047 return 0;
1048 }
1049
1050 btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
1051 btrfs_free_path(path);
1052 *objectid = location.objectid;
1053 return 0;
1054 }
1055
1056 static int btrfs_fill_super(struct super_block *sb,
1057 struct btrfs_fs_devices *fs_devices,
1058 void *data, int silent)
1059 {
1060 struct inode *inode;
1061 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1062 struct btrfs_key key;
1063 int err;
1064
1065 sb->s_maxbytes = MAX_LFS_FILESIZE;
1066 sb->s_magic = BTRFS_SUPER_MAGIC;
1067 sb->s_op = &btrfs_super_ops;
1068 sb->s_d_op = &btrfs_dentry_operations;
1069 sb->s_export_op = &btrfs_export_ops;
1070 sb->s_xattr = btrfs_xattr_handlers;
1071 sb->s_time_gran = 1;
1072 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
1073 sb->s_flags |= MS_POSIXACL;
1074 #endif
1075 sb->s_flags |= MS_I_VERSION;
1076 sb->s_iflags |= SB_I_CGROUPWB;
1077 err = open_ctree(sb, fs_devices, (char *)data);
1078 if (err) {
1079 printk(KERN_ERR "BTRFS: open_ctree failed\n");
1080 return err;
1081 }
1082
1083 key.objectid = BTRFS_FIRST_FREE_OBJECTID;
1084 key.type = BTRFS_INODE_ITEM_KEY;
1085 key.offset = 0;
1086 inode = btrfs_iget(sb, &key, fs_info->fs_root, NULL);
1087 if (IS_ERR(inode)) {
1088 err = PTR_ERR(inode);
1089 goto fail_close;
1090 }
1091
1092 sb->s_root = d_make_root(inode);
1093 if (!sb->s_root) {
1094 err = -ENOMEM;
1095 goto fail_close;
1096 }
1097
1098 save_mount_options(sb, data);
1099 cleancache_init_fs(sb);
1100 sb->s_flags |= MS_ACTIVE;
1101 return 0;
1102
1103 fail_close:
1104 close_ctree(fs_info->tree_root);
1105 return err;
1106 }
1107
1108 int btrfs_sync_fs(struct super_block *sb, int wait)
1109 {
1110 struct btrfs_trans_handle *trans;
1111 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1112 struct btrfs_root *root = fs_info->tree_root;
1113
1114 trace_btrfs_sync_fs(wait);
1115
1116 if (!wait) {
1117 filemap_flush(fs_info->btree_inode->i_mapping);
1118 return 0;
1119 }
1120
1121 btrfs_wait_ordered_roots(fs_info, -1);
1122
1123 trans = btrfs_attach_transaction_barrier(root);
1124 if (IS_ERR(trans)) {
1125 /* no transaction, don't bother */
1126 if (PTR_ERR(trans) == -ENOENT) {
1127 /*
1128 * Exit unless we have some pending changes
1129 * that need to go through commit
1130 */
1131 if (fs_info->pending_changes == 0)
1132 return 0;
1133 /*
1134 * A non-blocking test if the fs is frozen. We must not
1135 * start a new transaction here otherwise a deadlock
1136 * happens. The pending operations are delayed to the
1137 * next commit after thawing.
1138 */
1139 if (__sb_start_write(sb, SB_FREEZE_WRITE, false))
1140 __sb_end_write(sb, SB_FREEZE_WRITE);
1141 else
1142 return 0;
1143 trans = btrfs_start_transaction(root, 0);
1144 }
1145 if (IS_ERR(trans))
1146 return PTR_ERR(trans);
1147 }
1148 return btrfs_commit_transaction(trans, root);
1149 }
1150
1151 static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
1152 {
1153 struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
1154 struct btrfs_root *root = info->tree_root;
1155 char *compress_type;
1156
1157 if (btrfs_test_opt(root, DEGRADED))
1158 seq_puts(seq, ",degraded");
1159 if (btrfs_test_opt(root, NODATASUM))
1160 seq_puts(seq, ",nodatasum");
1161 if (btrfs_test_opt(root, NODATACOW))
1162 seq_puts(seq, ",nodatacow");
1163 if (btrfs_test_opt(root, NOBARRIER))
1164 seq_puts(seq, ",nobarrier");
1165 if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE)
1166 seq_printf(seq, ",max_inline=%llu", info->max_inline);
1167 if (info->alloc_start != 0)
1168 seq_printf(seq, ",alloc_start=%llu", info->alloc_start);
1169 if (info->thread_pool_size != min_t(unsigned long,
1170 num_online_cpus() + 2, 8))
1171 seq_printf(seq, ",thread_pool=%d", info->thread_pool_size);
1172 if (btrfs_test_opt(root, COMPRESS)) {
1173 if (info->compress_type == BTRFS_COMPRESS_ZLIB)
1174 compress_type = "zlib";
1175 else
1176 compress_type = "lzo";
1177 if (btrfs_test_opt(root, FORCE_COMPRESS))
1178 seq_printf(seq, ",compress-force=%s", compress_type);
1179 else
1180 seq_printf(seq, ",compress=%s", compress_type);
1181 }
1182 if (btrfs_test_opt(root, NOSSD))
1183 seq_puts(seq, ",nossd");
1184 if (btrfs_test_opt(root, SSD_SPREAD))
1185 seq_puts(seq, ",ssd_spread");
1186 else if (btrfs_test_opt(root, SSD))
1187 seq_puts(seq, ",ssd");
1188 if (btrfs_test_opt(root, NOTREELOG))
1189 seq_puts(seq, ",notreelog");
1190 if (btrfs_test_opt(root, FLUSHONCOMMIT))
1191 seq_puts(seq, ",flushoncommit");
1192 if (btrfs_test_opt(root, DISCARD))
1193 seq_puts(seq, ",discard");
1194 if (!(root->fs_info->sb->s_flags & MS_POSIXACL))
1195 seq_puts(seq, ",noacl");
1196 if (btrfs_test_opt(root, SPACE_CACHE))
1197 seq_puts(seq, ",space_cache");
1198 else if (btrfs_test_opt(root, FREE_SPACE_TREE))
1199 seq_puts(seq, ",space_cache=v2");
1200 else
1201 seq_puts(seq, ",nospace_cache");
1202 if (btrfs_test_opt(root, RESCAN_UUID_TREE))
1203 seq_puts(seq, ",rescan_uuid_tree");
1204 if (btrfs_test_opt(root, CLEAR_CACHE))
1205 seq_puts(seq, ",clear_cache");
1206 if (btrfs_test_opt(root, USER_SUBVOL_RM_ALLOWED))
1207 seq_puts(seq, ",user_subvol_rm_allowed");
1208 if (btrfs_test_opt(root, ENOSPC_DEBUG))
1209 seq_puts(seq, ",enospc_debug");
1210 if (btrfs_test_opt(root, AUTO_DEFRAG))
1211 seq_puts(seq, ",autodefrag");
1212 if (btrfs_test_opt(root, INODE_MAP_CACHE))
1213 seq_puts(seq, ",inode_cache");
1214 if (btrfs_test_opt(root, SKIP_BALANCE))
1215 seq_puts(seq, ",skip_balance");
1216 if (btrfs_test_opt(root, RECOVERY))
1217 seq_puts(seq, ",recovery");
1218 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
1219 if (btrfs_test_opt(root, CHECK_INTEGRITY_INCLUDING_EXTENT_DATA))
1220 seq_puts(seq, ",check_int_data");
1221 else if (btrfs_test_opt(root, CHECK_INTEGRITY))
1222 seq_puts(seq, ",check_int");
1223 if (info->check_integrity_print_mask)
1224 seq_printf(seq, ",check_int_print_mask=%d",
1225 info->check_integrity_print_mask);
1226 #endif
1227 if (info->metadata_ratio)
1228 seq_printf(seq, ",metadata_ratio=%d",
1229 info->metadata_ratio);
1230 if (btrfs_test_opt(root, PANIC_ON_FATAL_ERROR))
1231 seq_puts(seq, ",fatal_errors=panic");
1232 if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL)
1233 seq_printf(seq, ",commit=%d", info->commit_interval);
1234 #ifdef CONFIG_BTRFS_DEBUG
1235 if (btrfs_test_opt(root, FRAGMENT_DATA))
1236 seq_puts(seq, ",fragment=data");
1237 if (btrfs_test_opt(root, FRAGMENT_METADATA))
1238 seq_puts(seq, ",fragment=metadata");
1239 #endif
1240 seq_printf(seq, ",subvolid=%llu",
1241 BTRFS_I(d_inode(dentry))->root->root_key.objectid);
1242 seq_puts(seq, ",subvol=");
1243 seq_dentry(seq, dentry, " \t\n\\");
1244 return 0;
1245 }
1246
1247 static int btrfs_test_super(struct super_block *s, void *data)
1248 {
1249 struct btrfs_fs_info *p = data;
1250 struct btrfs_fs_info *fs_info = btrfs_sb(s);
1251
1252 return fs_info->fs_devices == p->fs_devices;
1253 }
1254
1255 static int btrfs_set_super(struct super_block *s, void *data)
1256 {
1257 int err = set_anon_super(s, data);
1258 if (!err)
1259 s->s_fs_info = data;
1260 return err;
1261 }
1262
1263 /*
1264 * subvolumes are identified by ino 256
1265 */
1266 static inline int is_subvolume_inode(struct inode *inode)
1267 {
1268 if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
1269 return 1;
1270 return 0;
1271 }
1272
1273 /*
1274 * This will add subvolid=0 to the argument string while removing any subvol=
1275 * and subvolid= arguments to make sure we get the top-level root for path
1276 * walking to the subvol we want.
1277 */
1278 static char *setup_root_args(char *args)
1279 {
1280 char *buf, *dst, *sep;
1281
1282 if (!args)
1283 return kstrdup("subvolid=0", GFP_NOFS);
1284
1285 /* The worst case is that we add ",subvolid=0" to the end. */
1286 buf = dst = kmalloc(strlen(args) + strlen(",subvolid=0") + 1, GFP_NOFS);
1287 if (!buf)
1288 return NULL;
1289
1290 while (1) {
1291 sep = strchrnul(args, ',');
1292 if (!strstarts(args, "subvol=") &&
1293 !strstarts(args, "subvolid=")) {
1294 memcpy(dst, args, sep - args);
1295 dst += sep - args;
1296 *dst++ = ',';
1297 }
1298 if (*sep)
1299 args = sep + 1;
1300 else
1301 break;
1302 }
1303 strcpy(dst, "subvolid=0");
1304
1305 return buf;
1306 }
1307
1308 static struct dentry *mount_subvol(const char *subvol_name, u64 subvol_objectid,
1309 int flags, const char *device_name,
1310 char *data)
1311 {
1312 struct dentry *root;
1313 struct vfsmount *mnt = NULL;
1314 char *newargs;
1315 int ret;
1316
1317 newargs = setup_root_args(data);
1318 if (!newargs) {
1319 root = ERR_PTR(-ENOMEM);
1320 goto out;
1321 }
1322
1323 mnt = vfs_kern_mount(&btrfs_fs_type, flags, device_name, newargs);
1324 if (PTR_ERR_OR_ZERO(mnt) == -EBUSY) {
1325 if (flags & MS_RDONLY) {
1326 mnt = vfs_kern_mount(&btrfs_fs_type, flags & ~MS_RDONLY,
1327 device_name, newargs);
1328 } else {
1329 mnt = vfs_kern_mount(&btrfs_fs_type, flags | MS_RDONLY,
1330 device_name, newargs);
1331 if (IS_ERR(mnt)) {
1332 root = ERR_CAST(mnt);
1333 mnt = NULL;
1334 goto out;
1335 }
1336
1337 down_write(&mnt->mnt_sb->s_umount);
1338 ret = btrfs_remount(mnt->mnt_sb, &flags, NULL);
1339 up_write(&mnt->mnt_sb->s_umount);
1340 if (ret < 0) {
1341 root = ERR_PTR(ret);
1342 goto out;
1343 }
1344 }
1345 }
1346 if (IS_ERR(mnt)) {
1347 root = ERR_CAST(mnt);
1348 mnt = NULL;
1349 goto out;
1350 }
1351
1352 if (!subvol_name) {
1353 if (!subvol_objectid) {
1354 ret = get_default_subvol_objectid(btrfs_sb(mnt->mnt_sb),
1355 &subvol_objectid);
1356 if (ret) {
1357 root = ERR_PTR(ret);
1358 goto out;
1359 }
1360 }
1361 subvol_name = get_subvol_name_from_objectid(btrfs_sb(mnt->mnt_sb),
1362 subvol_objectid);
1363 if (IS_ERR(subvol_name)) {
1364 root = ERR_CAST(subvol_name);
1365 subvol_name = NULL;
1366 goto out;
1367 }
1368
1369 }
1370
1371 root = mount_subtree(mnt, subvol_name);
1372 /* mount_subtree() drops our reference on the vfsmount. */
1373 mnt = NULL;
1374
1375 if (!IS_ERR(root)) {
1376 struct super_block *s = root->d_sb;
1377 struct inode *root_inode = d_inode(root);
1378 u64 root_objectid = BTRFS_I(root_inode)->root->root_key.objectid;
1379
1380 ret = 0;
1381 if (!is_subvolume_inode(root_inode)) {
1382 pr_err("BTRFS: '%s' is not a valid subvolume\n",
1383 subvol_name);
1384 ret = -EINVAL;
1385 }
1386 if (subvol_objectid && root_objectid != subvol_objectid) {
1387 /*
1388 * This will also catch a race condition where a
1389 * subvolume which was passed by ID is renamed and
1390 * another subvolume is renamed over the old location.
1391 */
1392 pr_err("BTRFS: subvol '%s' does not match subvolid %llu\n",
1393 subvol_name, subvol_objectid);
1394 ret = -EINVAL;
1395 }
1396 if (ret) {
1397 dput(root);
1398 root = ERR_PTR(ret);
1399 deactivate_locked_super(s);
1400 }
1401 }
1402
1403 out:
1404 mntput(mnt);
1405 kfree(newargs);
1406 kfree(subvol_name);
1407 return root;
1408 }
1409
1410 static int parse_security_options(char *orig_opts,
1411 struct security_mnt_opts *sec_opts)
1412 {
1413 char *secdata = NULL;
1414 int ret = 0;
1415
1416 secdata = alloc_secdata();
1417 if (!secdata)
1418 return -ENOMEM;
1419 ret = security_sb_copy_data(orig_opts, secdata);
1420 if (ret) {
1421 free_secdata(secdata);
1422 return ret;
1423 }
1424 ret = security_sb_parse_opts_str(secdata, sec_opts);
1425 free_secdata(secdata);
1426 return ret;
1427 }
1428
1429 static int setup_security_options(struct btrfs_fs_info *fs_info,
1430 struct super_block *sb,
1431 struct security_mnt_opts *sec_opts)
1432 {
1433 int ret = 0;
1434
1435 /*
1436 * Call security_sb_set_mnt_opts() to check whether new sec_opts
1437 * is valid.
1438 */
1439 ret = security_sb_set_mnt_opts(sb, sec_opts, 0, NULL);
1440 if (ret)
1441 return ret;
1442
1443 #ifdef CONFIG_SECURITY
1444 if (!fs_info->security_opts.num_mnt_opts) {
1445 /* first time security setup, copy sec_opts to fs_info */
1446 memcpy(&fs_info->security_opts, sec_opts, sizeof(*sec_opts));
1447 } else {
1448 /*
1449 * Since SELinux(the only one supports security_mnt_opts) does
1450 * NOT support changing context during remount/mount same sb,
1451 * This must be the same or part of the same security options,
1452 * just free it.
1453 */
1454 security_free_mnt_opts(sec_opts);
1455 }
1456 #endif
1457 return ret;
1458 }
1459
1460 /*
1461 * Find a superblock for the given device / mount point.
1462 *
1463 * Note: This is based on get_sb_bdev from fs/super.c with a few additions
1464 * for multiple device setup. Make sure to keep it in sync.
1465 */
1466 static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
1467 const char *device_name, void *data)
1468 {
1469 struct block_device *bdev = NULL;
1470 struct super_block *s;
1471 struct btrfs_fs_devices *fs_devices = NULL;
1472 struct btrfs_fs_info *fs_info = NULL;
1473 struct security_mnt_opts new_sec_opts;
1474 fmode_t mode = FMODE_READ;
1475 char *subvol_name = NULL;
1476 u64 subvol_objectid = 0;
1477 int error = 0;
1478
1479 if (!(flags & MS_RDONLY))
1480 mode |= FMODE_WRITE;
1481
1482 error = btrfs_parse_early_options(data, mode, fs_type,
1483 &subvol_name, &subvol_objectid,
1484 &fs_devices);
1485 if (error) {
1486 kfree(subvol_name);
1487 return ERR_PTR(error);
1488 }
1489
1490 if (subvol_name || subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
1491 /* mount_subvol() will free subvol_name. */
1492 return mount_subvol(subvol_name, subvol_objectid, flags,
1493 device_name, data);
1494 }
1495
1496 security_init_mnt_opts(&new_sec_opts);
1497 if (data) {
1498 error = parse_security_options(data, &new_sec_opts);
1499 if (error)
1500 return ERR_PTR(error);
1501 }
1502
1503 error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices);
1504 if (error)
1505 goto error_sec_opts;
1506
1507 /*
1508 * Setup a dummy root and fs_info for test/set super. This is because
1509 * we don't actually fill this stuff out until open_ctree, but we need
1510 * it for searching for existing supers, so this lets us do that and
1511 * then open_ctree will properly initialize everything later.
1512 */
1513 fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_NOFS);
1514 if (!fs_info) {
1515 error = -ENOMEM;
1516 goto error_sec_opts;
1517 }
1518
1519 fs_info->fs_devices = fs_devices;
1520
1521 fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
1522 fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
1523 security_init_mnt_opts(&fs_info->security_opts);
1524 if (!fs_info->super_copy || !fs_info->super_for_commit) {
1525 error = -ENOMEM;
1526 goto error_fs_info;
1527 }
1528
1529 error = btrfs_open_devices(fs_devices, mode, fs_type);
1530 if (error)
1531 goto error_fs_info;
1532
1533 if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
1534 error = -EACCES;
1535 goto error_close_devices;
1536 }
1537
1538 bdev = fs_devices->latest_bdev;
1539 s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | MS_NOSEC,
1540 fs_info);
1541 if (IS_ERR(s)) {
1542 error = PTR_ERR(s);
1543 goto error_close_devices;
1544 }
1545
1546 if (s->s_root) {
1547 btrfs_close_devices(fs_devices);
1548 free_fs_info(fs_info);
1549 if ((flags ^ s->s_flags) & MS_RDONLY)
1550 error = -EBUSY;
1551 } else {
1552 snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev);
1553 btrfs_sb(s)->bdev_holder = fs_type;
1554 error = btrfs_fill_super(s, fs_devices, data,
1555 flags & MS_SILENT ? 1 : 0);
1556 }
1557 if (error) {
1558 deactivate_locked_super(s);
1559 goto error_sec_opts;
1560 }
1561
1562 fs_info = btrfs_sb(s);
1563 error = setup_security_options(fs_info, s, &new_sec_opts);
1564 if (error) {
1565 deactivate_locked_super(s);
1566 goto error_sec_opts;
1567 }
1568
1569 return dget(s->s_root);
1570
1571 error_close_devices:
1572 btrfs_close_devices(fs_devices);
1573 error_fs_info:
1574 free_fs_info(fs_info);
1575 error_sec_opts:
1576 security_free_mnt_opts(&new_sec_opts);
1577 return ERR_PTR(error);
1578 }
1579
1580 static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
1581 int new_pool_size, int old_pool_size)
1582 {
1583 if (new_pool_size == old_pool_size)
1584 return;
1585
1586 fs_info->thread_pool_size = new_pool_size;
1587
1588 btrfs_info(fs_info, "resize thread pool %d -> %d",
1589 old_pool_size, new_pool_size);
1590
1591 btrfs_workqueue_set_max(fs_info->workers, new_pool_size);
1592 btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size);
1593 btrfs_workqueue_set_max(fs_info->submit_workers, new_pool_size);
1594 btrfs_workqueue_set_max(fs_info->caching_workers, new_pool_size);
1595 btrfs_workqueue_set_max(fs_info->endio_workers, new_pool_size);
1596 btrfs_workqueue_set_max(fs_info->endio_meta_workers, new_pool_size);
1597 btrfs_workqueue_set_max(fs_info->endio_meta_write_workers,
1598 new_pool_size);
1599 btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size);
1600 btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
1601 btrfs_workqueue_set_max(fs_info->delayed_workers, new_pool_size);
1602 btrfs_workqueue_set_max(fs_info->readahead_workers, new_pool_size);
1603 btrfs_workqueue_set_max(fs_info->scrub_wr_completion_workers,
1604 new_pool_size);
1605 }
1606
1607 static inline void btrfs_remount_prepare(struct btrfs_fs_info *fs_info)
1608 {
1609 set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1610 }
1611
1612 static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info,
1613 unsigned long old_opts, int flags)
1614 {
1615 if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1616 (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1617 (flags & MS_RDONLY))) {
1618 /* wait for any defraggers to finish */
1619 wait_event(fs_info->transaction_wait,
1620 (atomic_read(&fs_info->defrag_running) == 0));
1621 if (flags & MS_RDONLY)
1622 sync_filesystem(fs_info->sb);
1623 }
1624 }
1625
1626 static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
1627 unsigned long old_opts)
1628 {
1629 /*
1630 * We need cleanup all defragable inodes if the autodefragment is
1631 * close or the fs is R/O.
1632 */
1633 if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1634 (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1635 (fs_info->sb->s_flags & MS_RDONLY))) {
1636 btrfs_cleanup_defrag_inodes(fs_info);
1637 }
1638
1639 clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1640 }
1641
1642 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
1643 {
1644 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1645 struct btrfs_root *root = fs_info->tree_root;
1646 unsigned old_flags = sb->s_flags;
1647 unsigned long old_opts = fs_info->mount_opt;
1648 unsigned long old_compress_type = fs_info->compress_type;
1649 u64 old_max_inline = fs_info->max_inline;
1650 u64 old_alloc_start = fs_info->alloc_start;
1651 int old_thread_pool_size = fs_info->thread_pool_size;
1652 unsigned int old_metadata_ratio = fs_info->metadata_ratio;
1653 int ret;
1654
1655 sync_filesystem(sb);
1656 btrfs_remount_prepare(fs_info);
1657
1658 if (data) {
1659 struct security_mnt_opts new_sec_opts;
1660
1661 security_init_mnt_opts(&new_sec_opts);
1662 ret = parse_security_options(data, &new_sec_opts);
1663 if (ret)
1664 goto restore;
1665 ret = setup_security_options(fs_info, sb,
1666 &new_sec_opts);
1667 if (ret) {
1668 security_free_mnt_opts(&new_sec_opts);
1669 goto restore;
1670 }
1671 }
1672
1673 ret = btrfs_parse_options(root, data);
1674 if (ret) {
1675 ret = -EINVAL;
1676 goto restore;
1677 }
1678
1679 btrfs_remount_begin(fs_info, old_opts, *flags);
1680 btrfs_resize_thread_pool(fs_info,
1681 fs_info->thread_pool_size, old_thread_pool_size);
1682
1683 if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1684 goto out;
1685
1686 if (*flags & MS_RDONLY) {
1687 /*
1688 * this also happens on 'umount -rf' or on shutdown, when
1689 * the filesystem is busy.
1690 */
1691 cancel_work_sync(&fs_info->async_reclaim_work);
1692
1693 /* wait for the uuid_scan task to finish */
1694 down(&fs_info->uuid_tree_rescan_sem);
1695 /* avoid complains from lockdep et al. */
1696 up(&fs_info->uuid_tree_rescan_sem);
1697
1698 sb->s_flags |= MS_RDONLY;
1699
1700 /*
1701 * Setting MS_RDONLY will put the cleaner thread to
1702 * sleep at the next loop if it's already active.
1703 * If it's already asleep, we'll leave unused block
1704 * groups on disk until we're mounted read-write again
1705 * unless we clean them up here.
1706 */
1707 btrfs_delete_unused_bgs(fs_info);
1708
1709 btrfs_dev_replace_suspend_for_unmount(fs_info);
1710 btrfs_scrub_cancel(fs_info);
1711 btrfs_pause_balance(fs_info);
1712
1713 ret = btrfs_commit_super(root);
1714 if (ret)
1715 goto restore;
1716 } else {
1717 if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state)) {
1718 btrfs_err(fs_info,
1719 "Remounting read-write after error is not allowed");
1720 ret = -EINVAL;
1721 goto restore;
1722 }
1723 if (fs_info->fs_devices->rw_devices == 0) {
1724 ret = -EACCES;
1725 goto restore;
1726 }
1727
1728 if (fs_info->fs_devices->missing_devices >
1729 fs_info->num_tolerated_disk_barrier_failures &&
1730 !(*flags & MS_RDONLY)) {
1731 btrfs_warn(fs_info,
1732 "too many missing devices, writeable remount is not allowed");
1733 ret = -EACCES;
1734 goto restore;
1735 }
1736
1737 if (btrfs_super_log_root(fs_info->super_copy) != 0) {
1738 ret = -EINVAL;
1739 goto restore;
1740 }
1741
1742 ret = btrfs_cleanup_fs_roots(fs_info);
1743 if (ret)
1744 goto restore;
1745
1746 /* recover relocation */
1747 mutex_lock(&fs_info->cleaner_mutex);
1748 ret = btrfs_recover_relocation(root);
1749 mutex_unlock(&fs_info->cleaner_mutex);
1750 if (ret)
1751 goto restore;
1752
1753 ret = btrfs_resume_balance_async(fs_info);
1754 if (ret)
1755 goto restore;
1756
1757 ret = btrfs_resume_dev_replace_async(fs_info);
1758 if (ret) {
1759 btrfs_warn(fs_info, "failed to resume dev_replace");
1760 goto restore;
1761 }
1762
1763 if (!fs_info->uuid_root) {
1764 btrfs_info(fs_info, "creating UUID tree");
1765 ret = btrfs_create_uuid_tree(fs_info);
1766 if (ret) {
1767 btrfs_warn(fs_info, "failed to create the UUID tree %d", ret);
1768 goto restore;
1769 }
1770 }
1771 sb->s_flags &= ~MS_RDONLY;
1772 }
1773 out:
1774 wake_up_process(fs_info->transaction_kthread);
1775 btrfs_remount_cleanup(fs_info, old_opts);
1776 return 0;
1777
1778 restore:
1779 /* We've hit an error - don't reset MS_RDONLY */
1780 if (sb->s_flags & MS_RDONLY)
1781 old_flags |= MS_RDONLY;
1782 sb->s_flags = old_flags;
1783 fs_info->mount_opt = old_opts;
1784 fs_info->compress_type = old_compress_type;
1785 fs_info->max_inline = old_max_inline;
1786 mutex_lock(&fs_info->chunk_mutex);
1787 fs_info->alloc_start = old_alloc_start;
1788 mutex_unlock(&fs_info->chunk_mutex);
1789 btrfs_resize_thread_pool(fs_info,
1790 old_thread_pool_size, fs_info->thread_pool_size);
1791 fs_info->metadata_ratio = old_metadata_ratio;
1792 btrfs_remount_cleanup(fs_info, old_opts);
1793 return ret;
1794 }
1795
1796 /* Used to sort the devices by max_avail(descending sort) */
1797 static int btrfs_cmp_device_free_bytes(const void *dev_info1,
1798 const void *dev_info2)
1799 {
1800 if (((struct btrfs_device_info *)dev_info1)->max_avail >
1801 ((struct btrfs_device_info *)dev_info2)->max_avail)
1802 return -1;
1803 else if (((struct btrfs_device_info *)dev_info1)->max_avail <
1804 ((struct btrfs_device_info *)dev_info2)->max_avail)
1805 return 1;
1806 else
1807 return 0;
1808 }
1809
1810 /*
1811 * sort the devices by max_avail, in which max free extent size of each device
1812 * is stored.(Descending Sort)
1813 */
1814 static inline void btrfs_descending_sort_devices(
1815 struct btrfs_device_info *devices,
1816 size_t nr_devices)
1817 {
1818 sort(devices, nr_devices, sizeof(struct btrfs_device_info),
1819 btrfs_cmp_device_free_bytes, NULL);
1820 }
1821
1822 /*
1823 * The helper to calc the free space on the devices that can be used to store
1824 * file data.
1825 */
1826 static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes)
1827 {
1828 struct btrfs_fs_info *fs_info = root->fs_info;
1829 struct btrfs_device_info *devices_info;
1830 struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
1831 struct btrfs_device *device;
1832 u64 skip_space;
1833 u64 type;
1834 u64 avail_space;
1835 u64 used_space;
1836 u64 min_stripe_size;
1837 int min_stripes = 1, num_stripes = 1;
1838 int i = 0, nr_devices;
1839 int ret;
1840
1841 /*
1842 * We aren't under the device list lock, so this is racey-ish, but good
1843 * enough for our purposes.
1844 */
1845 nr_devices = fs_info->fs_devices->open_devices;
1846 if (!nr_devices) {
1847 smp_mb();
1848 nr_devices = fs_info->fs_devices->open_devices;
1849 ASSERT(nr_devices);
1850 if (!nr_devices) {
1851 *free_bytes = 0;
1852 return 0;
1853 }
1854 }
1855
1856 devices_info = kmalloc_array(nr_devices, sizeof(*devices_info),
1857 GFP_NOFS);
1858 if (!devices_info)
1859 return -ENOMEM;
1860
1861 /* calc min stripe number for data space alloction */
1862 type = btrfs_get_alloc_profile(root, 1);
1863 if (type & BTRFS_BLOCK_GROUP_RAID0) {
1864 min_stripes = 2;
1865 num_stripes = nr_devices;
1866 } else if (type & BTRFS_BLOCK_GROUP_RAID1) {
1867 min_stripes = 2;
1868 num_stripes = 2;
1869 } else if (type & BTRFS_BLOCK_GROUP_RAID10) {
1870 min_stripes = 4;
1871 num_stripes = 4;
1872 }
1873
1874 if (type & BTRFS_BLOCK_GROUP_DUP)
1875 min_stripe_size = 2 * BTRFS_STRIPE_LEN;
1876 else
1877 min_stripe_size = BTRFS_STRIPE_LEN;
1878
1879 if (fs_info->alloc_start)
1880 mutex_lock(&fs_devices->device_list_mutex);
1881 rcu_read_lock();
1882 list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
1883 if (!device->in_fs_metadata || !device->bdev ||
1884 device->is_tgtdev_for_dev_replace)
1885 continue;
1886
1887 if (i >= nr_devices)
1888 break;
1889
1890 avail_space = device->total_bytes - device->bytes_used;
1891
1892 /* align with stripe_len */
1893 avail_space = div_u64(avail_space, BTRFS_STRIPE_LEN);
1894 avail_space *= BTRFS_STRIPE_LEN;
1895
1896 /*
1897 * In order to avoid overwritting the superblock on the drive,
1898 * btrfs starts at an offset of at least 1MB when doing chunk
1899 * allocation.
1900 */
1901 skip_space = SZ_1M;
1902
1903 /* user can set the offset in fs_info->alloc_start. */
1904 if (fs_info->alloc_start &&
1905 fs_info->alloc_start + BTRFS_STRIPE_LEN <=
1906 device->total_bytes) {
1907 rcu_read_unlock();
1908 skip_space = max(fs_info->alloc_start, skip_space);
1909
1910 /*
1911 * btrfs can not use the free space in
1912 * [0, skip_space - 1], we must subtract it from the
1913 * total. In order to implement it, we account the used
1914 * space in this range first.
1915 */
1916 ret = btrfs_account_dev_extents_size(device, 0,
1917 skip_space - 1,
1918 &used_space);
1919 if (ret) {
1920 kfree(devices_info);
1921 mutex_unlock(&fs_devices->device_list_mutex);
1922 return ret;
1923 }
1924
1925 rcu_read_lock();
1926
1927 /* calc the free space in [0, skip_space - 1] */
1928 skip_space -= used_space;
1929 }
1930
1931 /*
1932 * we can use the free space in [0, skip_space - 1], subtract
1933 * it from the total.
1934 */
1935 if (avail_space && avail_space >= skip_space)
1936 avail_space -= skip_space;
1937 else
1938 avail_space = 0;
1939
1940 if (avail_space < min_stripe_size)
1941 continue;
1942
1943 devices_info[i].dev = device;
1944 devices_info[i].max_avail = avail_space;
1945
1946 i++;
1947 }
1948 rcu_read_unlock();
1949 if (fs_info->alloc_start)
1950 mutex_unlock(&fs_devices->device_list_mutex);
1951
1952 nr_devices = i;
1953
1954 btrfs_descending_sort_devices(devices_info, nr_devices);
1955
1956 i = nr_devices - 1;
1957 avail_space = 0;
1958 while (nr_devices >= min_stripes) {
1959 if (num_stripes > nr_devices)
1960 num_stripes = nr_devices;
1961
1962 if (devices_info[i].max_avail >= min_stripe_size) {
1963 int j;
1964 u64 alloc_size;
1965
1966 avail_space += devices_info[i].max_avail * num_stripes;
1967 alloc_size = devices_info[i].max_avail;
1968 for (j = i + 1 - num_stripes; j <= i; j++)
1969 devices_info[j].max_avail -= alloc_size;
1970 }
1971 i--;
1972 nr_devices--;
1973 }
1974
1975 kfree(devices_info);
1976 *free_bytes = avail_space;
1977 return 0;
1978 }
1979
1980 /*
1981 * Calculate numbers for 'df', pessimistic in case of mixed raid profiles.
1982 *
1983 * If there's a redundant raid level at DATA block groups, use the respective
1984 * multiplier to scale the sizes.
1985 *
1986 * Unused device space usage is based on simulating the chunk allocator
1987 * algorithm that respects the device sizes, order of allocations and the
1988 * 'alloc_start' value, this is a close approximation of the actual use but
1989 * there are other factors that may change the result (like a new metadata
1990 * chunk).
1991 *
1992 * If metadata is exhausted, f_bavail will be 0.
1993 *
1994 * FIXME: not accurate for mixed block groups, total and free/used are ok,
1995 * available appears slightly larger.
1996 */
1997 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
1998 {
1999 struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
2000 struct btrfs_super_block *disk_super = fs_info->super_copy;
2001 struct list_head *head = &fs_info->space_info;
2002 struct btrfs_space_info *found;
2003 u64 total_used = 0;
2004 u64 total_free_data = 0;
2005 u64 total_free_meta = 0;
2006 int bits = dentry->d_sb->s_blocksize_bits;
2007 __be32 *fsid = (__be32 *)fs_info->fsid;
2008 unsigned factor = 1;
2009 struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
2010 int ret;
2011 u64 thresh = 0;
2012
2013 /*
2014 * holding chunk_muext to avoid allocating new chunks, holding
2015 * device_list_mutex to avoid the device being removed
2016 */
2017 rcu_read_lock();
2018 list_for_each_entry_rcu(found, head, list) {
2019 if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
2020 int i;
2021
2022 total_free_data += found->disk_total - found->disk_used;
2023 total_free_data -=
2024 btrfs_account_ro_block_groups_free_space(found);
2025
2026 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
2027 if (!list_empty(&found->block_groups[i])) {
2028 switch (i) {
2029 case BTRFS_RAID_DUP:
2030 case BTRFS_RAID_RAID1:
2031 case BTRFS_RAID_RAID10:
2032 factor = 2;
2033 }
2034 }
2035 }
2036 }
2037 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
2038 total_free_meta += found->disk_total - found->disk_used;
2039
2040 total_used += found->disk_used;
2041 }
2042
2043 rcu_read_unlock();
2044
2045 buf->f_blocks = div_u64(btrfs_super_total_bytes(disk_super), factor);
2046 buf->f_blocks >>= bits;
2047 buf->f_bfree = buf->f_blocks - (div_u64(total_used, factor) >> bits);
2048
2049 /* Account global block reserve as used, it's in logical size already */
2050 spin_lock(&block_rsv->lock);
2051 buf->f_bfree -= block_rsv->size >> bits;
2052 spin_unlock(&block_rsv->lock);
2053
2054 buf->f_bavail = div_u64(total_free_data, factor);
2055 ret = btrfs_calc_avail_data_space(fs_info->tree_root, &total_free_data);
2056 if (ret)
2057 return ret;
2058 buf->f_bavail += div_u64(total_free_data, factor);
2059 buf->f_bavail = buf->f_bavail >> bits;
2060
2061 /*
2062 * We calculate the remaining metadata space minus global reserve. If
2063 * this is (supposedly) smaller than zero, there's no space. But this
2064 * does not hold in practice, the exhausted state happens where's still
2065 * some positive delta. So we apply some guesswork and compare the
2066 * delta to a 4M threshold. (Practically observed delta was ~2M.)
2067 *
2068 * We probably cannot calculate the exact threshold value because this
2069 * depends on the internal reservations requested by various
2070 * operations, so some operations that consume a few metadata will
2071 * succeed even if the Avail is zero. But this is better than the other
2072 * way around.
2073 */
2074 thresh = 4 * 1024 * 1024;
2075
2076 if (total_free_meta - thresh < block_rsv->size)
2077 buf->f_bavail = 0;
2078
2079 buf->f_type = BTRFS_SUPER_MAGIC;
2080 buf->f_bsize = dentry->d_sb->s_blocksize;
2081 buf->f_namelen = BTRFS_NAME_LEN;
2082
2083 /* We treat it as constant endianness (it doesn't matter _which_)
2084 because we want the fsid to come out the same whether mounted
2085 on a big-endian or little-endian host */
2086 buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
2087 buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
2088 /* Mask in the root object ID too, to disambiguate subvols */
2089 buf->f_fsid.val[0] ^= BTRFS_I(d_inode(dentry))->root->objectid >> 32;
2090 buf->f_fsid.val[1] ^= BTRFS_I(d_inode(dentry))->root->objectid;
2091
2092 return 0;
2093 }
2094
2095 static void btrfs_kill_super(struct super_block *sb)
2096 {
2097 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2098 kill_anon_super(sb);
2099 free_fs_info(fs_info);
2100 }
2101
2102 static struct file_system_type btrfs_fs_type = {
2103 .owner = THIS_MODULE,
2104 .name = "btrfs",
2105 .mount = btrfs_mount,
2106 .kill_sb = btrfs_kill_super,
2107 .fs_flags = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,
2108 };
2109 MODULE_ALIAS_FS("btrfs");
2110
2111 static int btrfs_control_open(struct inode *inode, struct file *file)
2112 {
2113 /*
2114 * The control file's private_data is used to hold the
2115 * transaction when it is started and is used to keep
2116 * track of whether a transaction is already in progress.
2117 */
2118 file->private_data = NULL;
2119 return 0;
2120 }
2121
2122 /*
2123 * used by btrfsctl to scan devices when no FS is mounted
2124 */
2125 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
2126 unsigned long arg)
2127 {
2128 struct btrfs_ioctl_vol_args *vol;
2129 struct btrfs_fs_devices *fs_devices;
2130 int ret = -ENOTTY;
2131
2132 if (!capable(CAP_SYS_ADMIN))
2133 return -EPERM;
2134
2135 vol = memdup_user((void __user *)arg, sizeof(*vol));
2136 if (IS_ERR(vol))
2137 return PTR_ERR(vol);
2138
2139 switch (cmd) {
2140 case BTRFS_IOC_SCAN_DEV:
2141 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
2142 &btrfs_fs_type, &fs_devices);
2143 break;
2144 case BTRFS_IOC_DEVICES_READY:
2145 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
2146 &btrfs_fs_type, &fs_devices);
2147 if (ret)
2148 break;
2149 ret = !(fs_devices->num_devices == fs_devices->total_devices);
2150 break;
2151 }
2152
2153 kfree(vol);
2154 return ret;
2155 }
2156
2157 static int btrfs_freeze(struct super_block *sb)
2158 {
2159 struct btrfs_trans_handle *trans;
2160 struct btrfs_root *root = btrfs_sb(sb)->tree_root;
2161
2162 trans = btrfs_attach_transaction_barrier(root);
2163 if (IS_ERR(trans)) {
2164 /* no transaction, don't bother */
2165 if (PTR_ERR(trans) == -ENOENT)
2166 return 0;
2167 return PTR_ERR(trans);
2168 }
2169 return btrfs_commit_transaction(trans, root);
2170 }
2171
2172 static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
2173 {
2174 struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
2175 struct btrfs_fs_devices *cur_devices;
2176 struct btrfs_device *dev, *first_dev = NULL;
2177 struct list_head *head;
2178 struct rcu_string *name;
2179
2180 mutex_lock(&fs_info->fs_devices->device_list_mutex);
2181 cur_devices = fs_info->fs_devices;
2182 while (cur_devices) {
2183 head = &cur_devices->devices;
2184 list_for_each_entry(dev, head, dev_list) {
2185 if (dev->missing)
2186 continue;
2187 if (!dev->name)
2188 continue;
2189 if (!first_dev || dev->devid < first_dev->devid)
2190 first_dev = dev;
2191 }
2192 cur_devices = cur_devices->seed;
2193 }
2194
2195 if (first_dev) {
2196 rcu_read_lock();
2197 name = rcu_dereference(first_dev->name);
2198 seq_escape(m, name->str, " \t\n\\");
2199 rcu_read_unlock();
2200 } else {
2201 WARN_ON(1);
2202 }
2203 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2204 return 0;
2205 }
2206
2207 static const struct super_operations btrfs_super_ops = {
2208 .drop_inode = btrfs_drop_inode,
2209 .evict_inode = btrfs_evict_inode,
2210 .put_super = btrfs_put_super,
2211 .sync_fs = btrfs_sync_fs,
2212 .show_options = btrfs_show_options,
2213 .show_devname = btrfs_show_devname,
2214 .write_inode = btrfs_write_inode,
2215 .alloc_inode = btrfs_alloc_inode,
2216 .destroy_inode = btrfs_destroy_inode,
2217 .statfs = btrfs_statfs,
2218 .remount_fs = btrfs_remount,
2219 .freeze_fs = btrfs_freeze,
2220 };
2221
2222 static const struct file_operations btrfs_ctl_fops = {
2223 .open = btrfs_control_open,
2224 .unlocked_ioctl = btrfs_control_ioctl,
2225 .compat_ioctl = btrfs_control_ioctl,
2226 .owner = THIS_MODULE,
2227 .llseek = noop_llseek,
2228 };
2229
2230 static struct miscdevice btrfs_misc = {
2231 .minor = BTRFS_MINOR,
2232 .name = "btrfs-control",
2233 .fops = &btrfs_ctl_fops
2234 };
2235
2236 MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
2237 MODULE_ALIAS("devname:btrfs-control");
2238
2239 static int btrfs_interface_init(void)
2240 {
2241 return misc_register(&btrfs_misc);
2242 }
2243
2244 static void btrfs_interface_exit(void)
2245 {
2246 misc_deregister(&btrfs_misc);
2247 }
2248
2249 static void btrfs_print_info(void)
2250 {
2251 printk(KERN_INFO "Btrfs loaded"
2252 #ifdef CONFIG_BTRFS_DEBUG
2253 ", debug=on"
2254 #endif
2255 #ifdef CONFIG_BTRFS_ASSERT
2256 ", assert=on"
2257 #endif
2258 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
2259 ", integrity-checker=on"
2260 #endif
2261 "\n");
2262 }
2263
2264 static int btrfs_run_sanity_tests(void)
2265 {
2266 int ret;
2267
2268 ret = btrfs_init_test_fs();
2269 if (ret)
2270 return ret;
2271
2272 ret = btrfs_test_free_space_cache();
2273 if (ret)
2274 goto out;
2275 ret = btrfs_test_extent_buffer_operations();
2276 if (ret)
2277 goto out;
2278 ret = btrfs_test_extent_io();
2279 if (ret)
2280 goto out;
2281 ret = btrfs_test_inodes();
2282 if (ret)
2283 goto out;
2284 ret = btrfs_test_qgroups();
2285 if (ret)
2286 goto out;
2287 ret = btrfs_test_free_space_tree();
2288 out:
2289 btrfs_destroy_test_fs();
2290 return ret;
2291 }
2292
2293 static int __init init_btrfs_fs(void)
2294 {
2295 int err;
2296
2297 err = btrfs_hash_init();
2298 if (err)
2299 return err;
2300
2301 btrfs_props_init();
2302
2303 err = btrfs_init_sysfs();
2304 if (err)
2305 goto free_hash;
2306
2307 btrfs_init_compress();
2308
2309 err = btrfs_init_cachep();
2310 if (err)
2311 goto free_compress;
2312
2313 err = extent_io_init();
2314 if (err)
2315 goto free_cachep;
2316
2317 err = extent_map_init();
2318 if (err)
2319 goto free_extent_io;
2320
2321 err = ordered_data_init();
2322 if (err)
2323 goto free_extent_map;
2324
2325 err = btrfs_delayed_inode_init();
2326 if (err)
2327 goto free_ordered_data;
2328
2329 err = btrfs_auto_defrag_init();
2330 if (err)
2331 goto free_delayed_inode;
2332
2333 err = btrfs_delayed_ref_init();
2334 if (err)
2335 goto free_auto_defrag;
2336
2337 err = btrfs_prelim_ref_init();
2338 if (err)
2339 goto free_delayed_ref;
2340
2341 err = btrfs_end_io_wq_init();
2342 if (err)
2343 goto free_prelim_ref;
2344
2345 err = btrfs_interface_init();
2346 if (err)
2347 goto free_end_io_wq;
2348
2349 btrfs_init_lockdep();
2350
2351 btrfs_print_info();
2352
2353 err = btrfs_run_sanity_tests();
2354 if (err)
2355 goto unregister_ioctl;
2356
2357 err = register_filesystem(&btrfs_fs_type);
2358 if (err)
2359 goto unregister_ioctl;
2360
2361 return 0;
2362
2363 unregister_ioctl:
2364 btrfs_interface_exit();
2365 free_end_io_wq:
2366 btrfs_end_io_wq_exit();
2367 free_prelim_ref:
2368 btrfs_prelim_ref_exit();
2369 free_delayed_ref:
2370 btrfs_delayed_ref_exit();
2371 free_auto_defrag:
2372 btrfs_auto_defrag_exit();
2373 free_delayed_inode:
2374 btrfs_delayed_inode_exit();
2375 free_ordered_data:
2376 ordered_data_exit();
2377 free_extent_map:
2378 extent_map_exit();
2379 free_extent_io:
2380 extent_io_exit();
2381 free_cachep:
2382 btrfs_destroy_cachep();
2383 free_compress:
2384 btrfs_exit_compress();
2385 btrfs_exit_sysfs();
2386 free_hash:
2387 btrfs_hash_exit();
2388 return err;
2389 }
2390
2391 static void __exit exit_btrfs_fs(void)
2392 {
2393 btrfs_destroy_cachep();
2394 btrfs_delayed_ref_exit();
2395 btrfs_auto_defrag_exit();
2396 btrfs_delayed_inode_exit();
2397 btrfs_prelim_ref_exit();
2398 ordered_data_exit();
2399 extent_map_exit();
2400 extent_io_exit();
2401 btrfs_interface_exit();
2402 btrfs_end_io_wq_exit();
2403 unregister_filesystem(&btrfs_fs_type);
2404 btrfs_exit_sysfs();
2405 btrfs_cleanup_fs_uuids();
2406 btrfs_exit_compress();
2407 btrfs_hash_exit();
2408 }
2409
2410 late_initcall(init_btrfs_fs);
2411 module_exit(exit_btrfs_fs)
2412
2413 MODULE_LICENSE("GPL");
Linux kernel - Deliverables
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