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Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6
[linux/fpc-iii.git] / fs / btrfs / super.c
blob4e59a91a11e0447ab05f5c39b9f5baa58121fc23
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 /* btrfs handle error by forcing the filesystem readonly */
101 static void btrfs_handle_error(struct btrfs_fs_info *fs_info)
102 {
103 struct super_block *sb = fs_info->sb;
104
105 if (sb->s_flags & MS_RDONLY)
106 return;
107
108 if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
109 sb->s_flags |= MS_RDONLY;
110 btrfs_info(fs_info, "forced readonly");
111 /*
112 * Note that a running device replace operation is not
113 * canceled here although there is no way to update
114 * the progress. It would add the risk of a deadlock,
115 * therefore the canceling is omitted. The only penalty
116 * is that some I/O remains active until the procedure
117 * completes. The next time when the filesystem is
118 * mounted writeable again, the device replace
119 * operation continues.
120 */
121 }
122 }
123
124 /*
125 * __btrfs_handle_fs_error decodes expected errors from the caller and
126 * invokes the approciate error response.
127 */
128 __cold
129 void __btrfs_handle_fs_error(struct btrfs_fs_info *fs_info, const char *function,
130 unsigned int line, int errno, const char *fmt, ...)
131 {
132 struct super_block *sb = fs_info->sb;
133 #ifdef CONFIG_PRINTK
134 const char *errstr;
135 #endif
136
137 /*
138 * Special case: if the error is EROFS, and we're already
139 * under MS_RDONLY, then it is safe here.
140 */
141 if (errno == -EROFS && (sb->s_flags & MS_RDONLY))
142 return;
143
144 #ifdef CONFIG_PRINTK
145 errstr = btrfs_decode_error(errno);
146 if (fmt) {
147 struct va_format vaf;
148 va_list args;
149
150 va_start(args, fmt);
151 vaf.fmt = fmt;
152 vaf.va = &args;
153
154 printk(KERN_CRIT
155 "BTRFS: error (device %s) in %s:%d: errno=%d %s (%pV)\n",
156 sb->s_id, function, line, errno, errstr, &vaf);
157 va_end(args);
158 } else {
159 printk(KERN_CRIT "BTRFS: error (device %s) in %s:%d: errno=%d %s\n",
160 sb->s_id, function, line, errno, errstr);
161 }
162 #endif
163
164 /*
165 * Today we only save the error info to memory. Long term we'll
166 * also send it down to the disk
167 */
168 set_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state);
169
170 /* Don't go through full error handling during mount */
171 if (sb->s_flags & MS_BORN)
172 btrfs_handle_error(fs_info);
173 }
174
175 #ifdef CONFIG_PRINTK
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 #endif
216
217 /*
218 * We only mark the transaction aborted and then set the file system read-only.
219 * This will prevent new transactions from starting or trying to join this
220 * one.
221 *
222 * This means that error recovery at the call site is limited to freeing
223 * any local memory allocations and passing the error code up without
224 * further cleanup. The transaction should complete as it normally would
225 * in the call path but will return -EIO.
226 *
227 * We'll complete the cleanup in btrfs_end_transaction and
228 * btrfs_commit_transaction.
229 */
230 __cold
231 void __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
232 struct btrfs_root *root, const char *function,
233 unsigned int line, int errno)
234 {
235 trans->aborted = errno;
236 /* Nothing used. The other threads that have joined this
237 * transaction may be able to continue. */
238 if (!trans->blocks_used && list_empty(&trans->new_bgs)) {
239 const char *errstr;
240
241 errstr = btrfs_decode_error(errno);
242 btrfs_warn(root->fs_info,
243 "%s:%d: Aborting unused transaction(%s).",
244 function, line, errstr);
245 return;
246 }
247 ACCESS_ONCE(trans->transaction->aborted) = errno;
248 /* Wake up anybody who may be waiting on this transaction */
249 wake_up(&root->fs_info->transaction_wait);
250 wake_up(&root->fs_info->transaction_blocked_wait);
251 __btrfs_handle_fs_error(root->fs_info, function, line, errno, NULL);
252 }
253 /*
254 * __btrfs_panic decodes unexpected, fatal errors from the caller,
255 * issues an alert, and either panics or BUGs, depending on mount options.
256 */
257 __cold
258 void __btrfs_panic(struct btrfs_fs_info *fs_info, const char *function,
259 unsigned int line, int errno, const char *fmt, ...)
260 {
261 char *s_id = "<unknown>";
262 const char *errstr;
263 struct va_format vaf = { .fmt = fmt };
264 va_list args;
265
266 if (fs_info)
267 s_id = fs_info->sb->s_id;
268
269 va_start(args, fmt);
270 vaf.va = &args;
271
272 errstr = btrfs_decode_error(errno);
273 if (fs_info && (fs_info->mount_opt & BTRFS_MOUNT_PANIC_ON_FATAL_ERROR))
274 panic(KERN_CRIT "BTRFS panic (device %s) in %s:%d: %pV (errno=%d %s)\n",
275 s_id, function, line, &vaf, errno, errstr);
276
277 btrfs_crit(fs_info, "panic in %s:%d: %pV (errno=%d %s)",
278 function, line, &vaf, errno, errstr);
279 va_end(args);
280 /* Caller calls BUG() */
281 }
282
283 static void btrfs_put_super(struct super_block *sb)
284 {
285 close_ctree(btrfs_sb(sb)->tree_root);
286 }
287
288 enum {
289 Opt_degraded, Opt_subvol, Opt_subvolid, Opt_device, Opt_nodatasum,
290 Opt_nodatacow, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd,
291 Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl, Opt_compress,
292 Opt_compress_type, Opt_compress_force, Opt_compress_force_type,
293 Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard,
294 Opt_space_cache, Opt_space_cache_version, Opt_clear_cache,
295 Opt_user_subvol_rm_allowed, Opt_enospc_debug, Opt_subvolrootid,
296 Opt_defrag, Opt_inode_cache, Opt_no_space_cache, Opt_recovery,
297 Opt_skip_balance, Opt_check_integrity,
298 Opt_check_integrity_including_extent_data,
299 Opt_check_integrity_print_mask, Opt_fatal_errors, Opt_rescan_uuid_tree,
300 Opt_commit_interval, Opt_barrier, Opt_nodefrag, Opt_nodiscard,
301 Opt_noenospc_debug, Opt_noflushoncommit, Opt_acl, Opt_datacow,
302 Opt_datasum, Opt_treelog, Opt_noinode_cache, Opt_usebackuproot,
303 Opt_nologreplay, Opt_norecovery,
304 #ifdef CONFIG_BTRFS_DEBUG
305 Opt_fragment_data, Opt_fragment_metadata, Opt_fragment_all,
306 #endif
307 Opt_err,
308 };
309
310 static const match_table_t tokens = {
311 {Opt_degraded, "degraded"},
312 {Opt_subvol, "subvol=%s"},
313 {Opt_subvolid, "subvolid=%s"},
314 {Opt_device, "device=%s"},
315 {Opt_nodatasum, "nodatasum"},
316 {Opt_datasum, "datasum"},
317 {Opt_nodatacow, "nodatacow"},
318 {Opt_datacow, "datacow"},
319 {Opt_nobarrier, "nobarrier"},
320 {Opt_barrier, "barrier"},
321 {Opt_max_inline, "max_inline=%s"},
322 {Opt_alloc_start, "alloc_start=%s"},
323 {Opt_thread_pool, "thread_pool=%d"},
324 {Opt_compress, "compress"},
325 {Opt_compress_type, "compress=%s"},
326 {Opt_compress_force, "compress-force"},
327 {Opt_compress_force_type, "compress-force=%s"},
328 {Opt_ssd, "ssd"},
329 {Opt_ssd_spread, "ssd_spread"},
330 {Opt_nossd, "nossd"},
331 {Opt_acl, "acl"},
332 {Opt_noacl, "noacl"},
333 {Opt_notreelog, "notreelog"},
334 {Opt_treelog, "treelog"},
335 {Opt_nologreplay, "nologreplay"},
336 {Opt_norecovery, "norecovery"},
337 {Opt_flushoncommit, "flushoncommit"},
338 {Opt_noflushoncommit, "noflushoncommit"},
339 {Opt_ratio, "metadata_ratio=%d"},
340 {Opt_discard, "discard"},
341 {Opt_nodiscard, "nodiscard"},
342 {Opt_space_cache, "space_cache"},
343 {Opt_space_cache_version, "space_cache=%s"},
344 {Opt_clear_cache, "clear_cache"},
345 {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
346 {Opt_enospc_debug, "enospc_debug"},
347 {Opt_noenospc_debug, "noenospc_debug"},
348 {Opt_subvolrootid, "subvolrootid=%d"},
349 {Opt_defrag, "autodefrag"},
350 {Opt_nodefrag, "noautodefrag"},
351 {Opt_inode_cache, "inode_cache"},
352 {Opt_noinode_cache, "noinode_cache"},
353 {Opt_no_space_cache, "nospace_cache"},
354 {Opt_recovery, "recovery"}, /* deprecated */
355 {Opt_usebackuproot, "usebackuproot"},
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 unsigned long new_flags)
378 {
379 struct btrfs_fs_info *info = root->fs_info;
380 substring_t args[MAX_OPT_ARGS];
381 char *p, *num, *orig = NULL;
382 u64 cache_gen;
383 int intarg;
384 int ret = 0;
385 char *compress_type;
386 bool compress_force = false;
387 enum btrfs_compression_type saved_compress_type;
388 bool saved_compress_force;
389 int no_compress = 0;
390
391 cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
392 if (btrfs_fs_compat_ro(root->fs_info, FREE_SPACE_TREE))
393 btrfs_set_opt(info->mount_opt, FREE_SPACE_TREE);
394 else if (cache_gen)
395 btrfs_set_opt(info->mount_opt, SPACE_CACHE);
396
397 /*
398 * Even the options are empty, we still need to do extra check
399 * against new flags
400 */
401 if (!options)
402 goto check;
403
404 /*
405 * strsep changes the string, duplicate it because parse_options
406 * gets called twice
407 */
408 options = kstrdup(options, GFP_NOFS);
409 if (!options)
410 return -ENOMEM;
411
412 orig = options;
413
414 while ((p = strsep(&options, ",")) != NULL) {
415 int token;
416 if (!*p)
417 continue;
418
419 token = match_token(p, tokens, args);
420 switch (token) {
421 case Opt_degraded:
422 btrfs_info(root->fs_info, "allowing degraded mounts");
423 btrfs_set_opt(info->mount_opt, DEGRADED);
424 break;
425 case Opt_subvol:
426 case Opt_subvolid:
427 case Opt_subvolrootid:
428 case Opt_device:
429 /*
430 * These are parsed by btrfs_parse_early_options
431 * and can be happily ignored here.
432 */
433 break;
434 case Opt_nodatasum:
435 btrfs_set_and_info(root, NODATASUM,
436 "setting nodatasum");
437 break;
438 case Opt_datasum:
439 if (btrfs_test_opt(root, NODATASUM)) {
440 if (btrfs_test_opt(root, NODATACOW))
441 btrfs_info(root->fs_info, "setting datasum, datacow enabled");
442 else
443 btrfs_info(root->fs_info, "setting datasum");
444 }
445 btrfs_clear_opt(info->mount_opt, NODATACOW);
446 btrfs_clear_opt(info->mount_opt, NODATASUM);
447 break;
448 case Opt_nodatacow:
449 if (!btrfs_test_opt(root, NODATACOW)) {
450 if (!btrfs_test_opt(root, COMPRESS) ||
451 !btrfs_test_opt(root, FORCE_COMPRESS)) {
452 btrfs_info(root->fs_info,
453 "setting nodatacow, compression disabled");
454 } else {
455 btrfs_info(root->fs_info, "setting nodatacow");
456 }
457 }
458 btrfs_clear_opt(info->mount_opt, COMPRESS);
459 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
460 btrfs_set_opt(info->mount_opt, NODATACOW);
461 btrfs_set_opt(info->mount_opt, NODATASUM);
462 break;
463 case Opt_datacow:
464 btrfs_clear_and_info(root, NODATACOW,
465 "setting datacow");
466 break;
467 case Opt_compress_force:
468 case Opt_compress_force_type:
469 compress_force = true;
470 /* Fallthrough */
471 case Opt_compress:
472 case Opt_compress_type:
473 saved_compress_type = btrfs_test_opt(root, COMPRESS) ?
474 info->compress_type : BTRFS_COMPRESS_NONE;
475 saved_compress_force =
476 btrfs_test_opt(root, FORCE_COMPRESS);
477 if (token == Opt_compress ||
478 token == Opt_compress_force ||
479 strcmp(args[0].from, "zlib") == 0) {
480 compress_type = "zlib";
481 info->compress_type = BTRFS_COMPRESS_ZLIB;
482 btrfs_set_opt(info->mount_opt, COMPRESS);
483 btrfs_clear_opt(info->mount_opt, NODATACOW);
484 btrfs_clear_opt(info->mount_opt, NODATASUM);
485 no_compress = 0;
486 } else if (strcmp(args[0].from, "lzo") == 0) {
487 compress_type = "lzo";
488 info->compress_type = BTRFS_COMPRESS_LZO;
489 btrfs_set_opt(info->mount_opt, COMPRESS);
490 btrfs_clear_opt(info->mount_opt, NODATACOW);
491 btrfs_clear_opt(info->mount_opt, NODATASUM);
492 btrfs_set_fs_incompat(info, COMPRESS_LZO);
493 no_compress = 0;
494 } else if (strncmp(args[0].from, "no", 2) == 0) {
495 compress_type = "no";
496 btrfs_clear_opt(info->mount_opt, COMPRESS);
497 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
498 compress_force = false;
499 no_compress++;
500 } else {
501 ret = -EINVAL;
502 goto out;
503 }
504
505 if (compress_force) {
506 btrfs_set_opt(info->mount_opt, FORCE_COMPRESS);
507 } else {
508 /*
509 * If we remount from compress-force=xxx to
510 * compress=xxx, we need clear FORCE_COMPRESS
511 * flag, otherwise, there is no way for users
512 * to disable forcible compression separately.
513 */
514 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
515 }
516 if ((btrfs_test_opt(root, COMPRESS) &&
517 (info->compress_type != saved_compress_type ||
518 compress_force != saved_compress_force)) ||
519 (!btrfs_test_opt(root, COMPRESS) &&
520 no_compress == 1)) {
521 btrfs_info(root->fs_info,
522 "%s %s compression",
523 (compress_force) ? "force" : "use",
524 compress_type);
525 }
526 compress_force = false;
527 break;
528 case Opt_ssd:
529 btrfs_set_and_info(root, SSD,
530 "use ssd allocation scheme");
531 break;
532 case Opt_ssd_spread:
533 btrfs_set_and_info(root, SSD_SPREAD,
534 "use spread ssd allocation scheme");
535 btrfs_set_opt(info->mount_opt, SSD);
536 break;
537 case Opt_nossd:
538 btrfs_set_and_info(root, NOSSD,
539 "not using ssd allocation scheme");
540 btrfs_clear_opt(info->mount_opt, SSD);
541 break;
542 case Opt_barrier:
543 btrfs_clear_and_info(root, NOBARRIER,
544 "turning on barriers");
545 break;
546 case Opt_nobarrier:
547 btrfs_set_and_info(root, NOBARRIER,
548 "turning off barriers");
549 break;
550 case Opt_thread_pool:
551 ret = match_int(&args[0], &intarg);
552 if (ret) {
553 goto out;
554 } else if (intarg > 0) {
555 info->thread_pool_size = intarg;
556 } else {
557 ret = -EINVAL;
558 goto out;
559 }
560 break;
561 case Opt_max_inline:
562 num = match_strdup(&args[0]);
563 if (num) {
564 info->max_inline = memparse(num, NULL);
565 kfree(num);
566
567 if (info->max_inline) {
568 info->max_inline = min_t(u64,
569 info->max_inline,
570 root->sectorsize);
571 }
572 btrfs_info(root->fs_info, "max_inline at %llu",
573 info->max_inline);
574 } else {
575 ret = -ENOMEM;
576 goto out;
577 }
578 break;
579 case Opt_alloc_start:
580 num = match_strdup(&args[0]);
581 if (num) {
582 mutex_lock(&info->chunk_mutex);
583 info->alloc_start = memparse(num, NULL);
584 mutex_unlock(&info->chunk_mutex);
585 kfree(num);
586 btrfs_info(root->fs_info, "allocations start at %llu",
587 info->alloc_start);
588 } else {
589 ret = -ENOMEM;
590 goto out;
591 }
592 break;
593 case Opt_acl:
594 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
595 root->fs_info->sb->s_flags |= MS_POSIXACL;
596 break;
597 #else
598 btrfs_err(root->fs_info,
599 "support for ACL not compiled in!");
600 ret = -EINVAL;
601 goto out;
602 #endif
603 case Opt_noacl:
604 root->fs_info->sb->s_flags &= ~MS_POSIXACL;
605 break;
606 case Opt_notreelog:
607 btrfs_set_and_info(root, NOTREELOG,
608 "disabling tree log");
609 break;
610 case Opt_treelog:
611 btrfs_clear_and_info(root, NOTREELOG,
612 "enabling tree log");
613 break;
614 case Opt_norecovery:
615 case Opt_nologreplay:
616 btrfs_set_and_info(root, NOLOGREPLAY,
617 "disabling log replay at mount time");
618 break;
619 case Opt_flushoncommit:
620 btrfs_set_and_info(root, FLUSHONCOMMIT,
621 "turning on flush-on-commit");
622 break;
623 case Opt_noflushoncommit:
624 btrfs_clear_and_info(root, FLUSHONCOMMIT,
625 "turning off flush-on-commit");
626 break;
627 case Opt_ratio:
628 ret = match_int(&args[0], &intarg);
629 if (ret) {
630 goto out;
631 } else if (intarg >= 0) {
632 info->metadata_ratio = intarg;
633 btrfs_info(root->fs_info, "metadata ratio %d",
634 info->metadata_ratio);
635 } else {
636 ret = -EINVAL;
637 goto out;
638 }
639 break;
640 case Opt_discard:
641 btrfs_set_and_info(root, DISCARD,
642 "turning on discard");
643 break;
644 case Opt_nodiscard:
645 btrfs_clear_and_info(root, DISCARD,
646 "turning off discard");
647 break;
648 case Opt_space_cache:
649 case Opt_space_cache_version:
650 if (token == Opt_space_cache ||
651 strcmp(args[0].from, "v1") == 0) {
652 btrfs_clear_opt(root->fs_info->mount_opt,
653 FREE_SPACE_TREE);
654 btrfs_set_and_info(root, SPACE_CACHE,
655 "enabling disk space caching");
656 } else if (strcmp(args[0].from, "v2") == 0) {
657 btrfs_clear_opt(root->fs_info->mount_opt,
658 SPACE_CACHE);
659 btrfs_set_and_info(root, FREE_SPACE_TREE,
660 "enabling free space tree");
661 } else {
662 ret = -EINVAL;
663 goto out;
664 }
665 break;
666 case Opt_rescan_uuid_tree:
667 btrfs_set_opt(info->mount_opt, RESCAN_UUID_TREE);
668 break;
669 case Opt_no_space_cache:
670 if (btrfs_test_opt(root, SPACE_CACHE)) {
671 btrfs_clear_and_info(root, SPACE_CACHE,
672 "disabling disk space caching");
673 }
674 if (btrfs_test_opt(root, FREE_SPACE_TREE)) {
675 btrfs_clear_and_info(root, FREE_SPACE_TREE,
676 "disabling free space tree");
677 }
678 break;
679 case Opt_inode_cache:
680 btrfs_set_pending_and_info(info, INODE_MAP_CACHE,
681 "enabling inode map caching");
682 break;
683 case Opt_noinode_cache:
684 btrfs_clear_pending_and_info(info, INODE_MAP_CACHE,
685 "disabling inode map caching");
686 break;
687 case Opt_clear_cache:
688 btrfs_set_and_info(root, CLEAR_CACHE,
689 "force clearing of disk cache");
690 break;
691 case Opt_user_subvol_rm_allowed:
692 btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
693 break;
694 case Opt_enospc_debug:
695 btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
696 break;
697 case Opt_noenospc_debug:
698 btrfs_clear_opt(info->mount_opt, ENOSPC_DEBUG);
699 break;
700 case Opt_defrag:
701 btrfs_set_and_info(root, AUTO_DEFRAG,
702 "enabling auto defrag");
703 break;
704 case Opt_nodefrag:
705 btrfs_clear_and_info(root, AUTO_DEFRAG,
706 "disabling auto defrag");
707 break;
708 case Opt_recovery:
709 btrfs_warn(root->fs_info,
710 "'recovery' is deprecated, use 'usebackuproot' instead");
711 case Opt_usebackuproot:
712 btrfs_info(root->fs_info,
713 "trying to use backup root at mount time");
714 btrfs_set_opt(info->mount_opt, USEBACKUPROOT);
715 break;
716 case Opt_skip_balance:
717 btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
718 break;
719 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
720 case Opt_check_integrity_including_extent_data:
721 btrfs_info(root->fs_info,
722 "enabling check integrity including extent data");
723 btrfs_set_opt(info->mount_opt,
724 CHECK_INTEGRITY_INCLUDING_EXTENT_DATA);
725 btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
726 break;
727 case Opt_check_integrity:
728 btrfs_info(root->fs_info, "enabling check integrity");
729 btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
730 break;
731 case Opt_check_integrity_print_mask:
732 ret = match_int(&args[0], &intarg);
733 if (ret) {
734 goto out;
735 } else if (intarg >= 0) {
736 info->check_integrity_print_mask = intarg;
737 btrfs_info(root->fs_info, "check_integrity_print_mask 0x%x",
738 info->check_integrity_print_mask);
739 } else {
740 ret = -EINVAL;
741 goto out;
742 }
743 break;
744 #else
745 case Opt_check_integrity_including_extent_data:
746 case Opt_check_integrity:
747 case Opt_check_integrity_print_mask:
748 btrfs_err(root->fs_info,
749 "support for check_integrity* not compiled in!");
750 ret = -EINVAL;
751 goto out;
752 #endif
753 case Opt_fatal_errors:
754 if (strcmp(args[0].from, "panic") == 0)
755 btrfs_set_opt(info->mount_opt,
756 PANIC_ON_FATAL_ERROR);
757 else if (strcmp(args[0].from, "bug") == 0)
758 btrfs_clear_opt(info->mount_opt,
759 PANIC_ON_FATAL_ERROR);
760 else {
761 ret = -EINVAL;
762 goto out;
763 }
764 break;
765 case Opt_commit_interval:
766 intarg = 0;
767 ret = match_int(&args[0], &intarg);
768 if (ret < 0) {
769 btrfs_err(root->fs_info, "invalid commit interval");
770 ret = -EINVAL;
771 goto out;
772 }
773 if (intarg > 0) {
774 if (intarg > 300) {
775 btrfs_warn(root->fs_info, "excessive commit interval %d",
776 intarg);
777 }
778 info->commit_interval = intarg;
779 } else {
780 btrfs_info(root->fs_info, "using default commit interval %ds",
781 BTRFS_DEFAULT_COMMIT_INTERVAL);
782 info->commit_interval = BTRFS_DEFAULT_COMMIT_INTERVAL;
783 }
784 break;
785 #ifdef CONFIG_BTRFS_DEBUG
786 case Opt_fragment_all:
787 btrfs_info(root->fs_info, "fragmenting all space");
788 btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
789 btrfs_set_opt(info->mount_opt, FRAGMENT_METADATA);
790 break;
791 case Opt_fragment_metadata:
792 btrfs_info(root->fs_info, "fragmenting metadata");
793 btrfs_set_opt(info->mount_opt,
794 FRAGMENT_METADATA);
795 break;
796 case Opt_fragment_data:
797 btrfs_info(root->fs_info, "fragmenting data");
798 btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
799 break;
800 #endif
801 case Opt_err:
802 btrfs_info(root->fs_info, "unrecognized mount option '%s'", p);
803 ret = -EINVAL;
804 goto out;
805 default:
806 break;
807 }
808 }
809 check:
810 /*
811 * Extra check for current option against current flag
812 */
813 if (btrfs_test_opt(root, NOLOGREPLAY) && !(new_flags & MS_RDONLY)) {
814 btrfs_err(root->fs_info,
815 "nologreplay must be used with ro mount option");
816 ret = -EINVAL;
817 }
818 out:
819 if (btrfs_fs_compat_ro(root->fs_info, FREE_SPACE_TREE) &&
820 !btrfs_test_opt(root, FREE_SPACE_TREE) &&
821 !btrfs_test_opt(root, CLEAR_CACHE)) {
822 btrfs_err(root->fs_info, "cannot disable free space tree");
823 ret = -EINVAL;
824
825 }
826 if (!ret && btrfs_test_opt(root, SPACE_CACHE))
827 btrfs_info(root->fs_info, "disk space caching is enabled");
828 if (!ret && btrfs_test_opt(root, FREE_SPACE_TREE))
829 btrfs_info(root->fs_info, "using free space tree");
830 kfree(orig);
831 return ret;
832 }
833
834 /*
835 * Parse mount options that are required early in the mount process.
836 *
837 * All other options will be parsed on much later in the mount process and
838 * only when we need to allocate a new super block.
839 */
840 static int btrfs_parse_early_options(const char *options, fmode_t flags,
841 void *holder, char **subvol_name, u64 *subvol_objectid,
842 struct btrfs_fs_devices **fs_devices)
843 {
844 substring_t args[MAX_OPT_ARGS];
845 char *device_name, *opts, *orig, *p;
846 char *num = NULL;
847 int error = 0;
848
849 if (!options)
850 return 0;
851
852 /*
853 * strsep changes the string, duplicate it because parse_options
854 * gets called twice
855 */
856 opts = kstrdup(options, GFP_KERNEL);
857 if (!opts)
858 return -ENOMEM;
859 orig = opts;
860
861 while ((p = strsep(&opts, ",")) != NULL) {
862 int token;
863 if (!*p)
864 continue;
865
866 token = match_token(p, tokens, args);
867 switch (token) {
868 case Opt_subvol:
869 kfree(*subvol_name);
870 *subvol_name = match_strdup(&args[0]);
871 if (!*subvol_name) {
872 error = -ENOMEM;
873 goto out;
874 }
875 break;
876 case Opt_subvolid:
877 num = match_strdup(&args[0]);
878 if (num) {
879 *subvol_objectid = memparse(num, NULL);
880 kfree(num);
881 /* we want the original fs_tree */
882 if (!*subvol_objectid)
883 *subvol_objectid =
884 BTRFS_FS_TREE_OBJECTID;
885 } else {
886 error = -EINVAL;
887 goto out;
888 }
889 break;
890 case Opt_subvolrootid:
891 printk(KERN_WARNING
892 "BTRFS: 'subvolrootid' mount option is deprecated and has "
893 "no effect\n");
894 break;
895 case Opt_device:
896 device_name = match_strdup(&args[0]);
897 if (!device_name) {
898 error = -ENOMEM;
899 goto out;
900 }
901 error = btrfs_scan_one_device(device_name,
902 flags, holder, fs_devices);
903 kfree(device_name);
904 if (error)
905 goto out;
906 break;
907 default:
908 break;
909 }
910 }
911
912 out:
913 kfree(orig);
914 return error;
915 }
916
917 static char *get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
918 u64 subvol_objectid)
919 {
920 struct btrfs_root *root = fs_info->tree_root;
921 struct btrfs_root *fs_root;
922 struct btrfs_root_ref *root_ref;
923 struct btrfs_inode_ref *inode_ref;
924 struct btrfs_key key;
925 struct btrfs_path *path = NULL;
926 char *name = NULL, *ptr;
927 u64 dirid;
928 int len;
929 int ret;
930
931 path = btrfs_alloc_path();
932 if (!path) {
933 ret = -ENOMEM;
934 goto err;
935 }
936 path->leave_spinning = 1;
937
938 name = kmalloc(PATH_MAX, GFP_NOFS);
939 if (!name) {
940 ret = -ENOMEM;
941 goto err;
942 }
943 ptr = name + PATH_MAX - 1;
944 ptr[0] = '\0';
945
946 /*
947 * Walk up the subvolume trees in the tree of tree roots by root
948 * backrefs until we hit the top-level subvolume.
949 */
950 while (subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
951 key.objectid = subvol_objectid;
952 key.type = BTRFS_ROOT_BACKREF_KEY;
953 key.offset = (u64)-1;
954
955 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
956 if (ret < 0) {
957 goto err;
958 } else if (ret > 0) {
959 ret = btrfs_previous_item(root, path, subvol_objectid,
960 BTRFS_ROOT_BACKREF_KEY);
961 if (ret < 0) {
962 goto err;
963 } else if (ret > 0) {
964 ret = -ENOENT;
965 goto err;
966 }
967 }
968
969 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
970 subvol_objectid = key.offset;
971
972 root_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
973 struct btrfs_root_ref);
974 len = btrfs_root_ref_name_len(path->nodes[0], root_ref);
975 ptr -= len + 1;
976 if (ptr < name) {
977 ret = -ENAMETOOLONG;
978 goto err;
979 }
980 read_extent_buffer(path->nodes[0], ptr + 1,
981 (unsigned long)(root_ref + 1), len);
982 ptr[0] = '/';
983 dirid = btrfs_root_ref_dirid(path->nodes[0], root_ref);
984 btrfs_release_path(path);
985
986 key.objectid = subvol_objectid;
987 key.type = BTRFS_ROOT_ITEM_KEY;
988 key.offset = (u64)-1;
989 fs_root = btrfs_read_fs_root_no_name(fs_info, &key);
990 if (IS_ERR(fs_root)) {
991 ret = PTR_ERR(fs_root);
992 goto err;
993 }
994
995 /*
996 * Walk up the filesystem tree by inode refs until we hit the
997 * root directory.
998 */
999 while (dirid != BTRFS_FIRST_FREE_OBJECTID) {
1000 key.objectid = dirid;
1001 key.type = BTRFS_INODE_REF_KEY;
1002 key.offset = (u64)-1;
1003
1004 ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0);
1005 if (ret < 0) {
1006 goto err;
1007 } else if (ret > 0) {
1008 ret = btrfs_previous_item(fs_root, path, dirid,
1009 BTRFS_INODE_REF_KEY);
1010 if (ret < 0) {
1011 goto err;
1012 } else if (ret > 0) {
1013 ret = -ENOENT;
1014 goto err;
1015 }
1016 }
1017
1018 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1019 dirid = key.offset;
1020
1021 inode_ref = btrfs_item_ptr(path->nodes[0],
1022 path->slots[0],
1023 struct btrfs_inode_ref);
1024 len = btrfs_inode_ref_name_len(path->nodes[0],
1025 inode_ref);
1026 ptr -= len + 1;
1027 if (ptr < name) {
1028 ret = -ENAMETOOLONG;
1029 goto err;
1030 }
1031 read_extent_buffer(path->nodes[0], ptr + 1,
1032 (unsigned long)(inode_ref + 1), len);
1033 ptr[0] = '/';
1034 btrfs_release_path(path);
1035 }
1036 }
1037
1038 btrfs_free_path(path);
1039 if (ptr == name + PATH_MAX - 1) {
1040 name[0] = '/';
1041 name[1] = '\0';
1042 } else {
1043 memmove(name, ptr, name + PATH_MAX - ptr);
1044 }
1045 return name;
1046
1047 err:
1048 btrfs_free_path(path);
1049 kfree(name);
1050 return ERR_PTR(ret);
1051 }
1052
1053 static int get_default_subvol_objectid(struct btrfs_fs_info *fs_info, u64 *objectid)
1054 {
1055 struct btrfs_root *root = fs_info->tree_root;
1056 struct btrfs_dir_item *di;
1057 struct btrfs_path *path;
1058 struct btrfs_key location;
1059 u64 dir_id;
1060
1061 path = btrfs_alloc_path();
1062 if (!path)
1063 return -ENOMEM;
1064 path->leave_spinning = 1;
1065
1066 /*
1067 * Find the "default" dir item which points to the root item that we
1068 * will mount by default if we haven't been given a specific subvolume
1069 * to mount.
1070 */
1071 dir_id = btrfs_super_root_dir(fs_info->super_copy);
1072 di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
1073 if (IS_ERR(di)) {
1074 btrfs_free_path(path);
1075 return PTR_ERR(di);
1076 }
1077 if (!di) {
1078 /*
1079 * Ok the default dir item isn't there. This is weird since
1080 * it's always been there, but don't freak out, just try and
1081 * mount the top-level subvolume.
1082 */
1083 btrfs_free_path(path);
1084 *objectid = BTRFS_FS_TREE_OBJECTID;
1085 return 0;
1086 }
1087
1088 btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
1089 btrfs_free_path(path);
1090 *objectid = location.objectid;
1091 return 0;
1092 }
1093
1094 static int btrfs_fill_super(struct super_block *sb,
1095 struct btrfs_fs_devices *fs_devices,
1096 void *data, int silent)
1097 {
1098 struct inode *inode;
1099 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1100 struct btrfs_key key;
1101 int err;
1102
1103 sb->s_maxbytes = MAX_LFS_FILESIZE;
1104 sb->s_magic = BTRFS_SUPER_MAGIC;
1105 sb->s_op = &btrfs_super_ops;
1106 sb->s_d_op = &btrfs_dentry_operations;
1107 sb->s_export_op = &btrfs_export_ops;
1108 sb->s_xattr = btrfs_xattr_handlers;
1109 sb->s_time_gran = 1;
1110 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
1111 sb->s_flags |= MS_POSIXACL;
1112 #endif
1113 sb->s_flags |= MS_I_VERSION;
1114 sb->s_iflags |= SB_I_CGROUPWB;
1115 err = open_ctree(sb, fs_devices, (char *)data);
1116 if (err) {
1117 printk(KERN_ERR "BTRFS: open_ctree failed\n");
1118 return err;
1119 }
1120
1121 key.objectid = BTRFS_FIRST_FREE_OBJECTID;
1122 key.type = BTRFS_INODE_ITEM_KEY;
1123 key.offset = 0;
1124 inode = btrfs_iget(sb, &key, fs_info->fs_root, NULL);
1125 if (IS_ERR(inode)) {
1126 err = PTR_ERR(inode);
1127 goto fail_close;
1128 }
1129
1130 sb->s_root = d_make_root(inode);
1131 if (!sb->s_root) {
1132 err = -ENOMEM;
1133 goto fail_close;
1134 }
1135
1136 save_mount_options(sb, data);
1137 cleancache_init_fs(sb);
1138 sb->s_flags |= MS_ACTIVE;
1139 return 0;
1140
1141 fail_close:
1142 close_ctree(fs_info->tree_root);
1143 return err;
1144 }
1145
1146 int btrfs_sync_fs(struct super_block *sb, int wait)
1147 {
1148 struct btrfs_trans_handle *trans;
1149 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1150 struct btrfs_root *root = fs_info->tree_root;
1151
1152 trace_btrfs_sync_fs(wait);
1153
1154 if (!wait) {
1155 filemap_flush(fs_info->btree_inode->i_mapping);
1156 return 0;
1157 }
1158
1159 btrfs_wait_ordered_roots(fs_info, -1, 0, (u64)-1);
1160
1161 trans = btrfs_attach_transaction_barrier(root);
1162 if (IS_ERR(trans)) {
1163 /* no transaction, don't bother */
1164 if (PTR_ERR(trans) == -ENOENT) {
1165 /*
1166 * Exit unless we have some pending changes
1167 * that need to go through commit
1168 */
1169 if (fs_info->pending_changes == 0)
1170 return 0;
1171 /*
1172 * A non-blocking test if the fs is frozen. We must not
1173 * start a new transaction here otherwise a deadlock
1174 * happens. The pending operations are delayed to the
1175 * next commit after thawing.
1176 */
1177 if (__sb_start_write(sb, SB_FREEZE_WRITE, false))
1178 __sb_end_write(sb, SB_FREEZE_WRITE);
1179 else
1180 return 0;
1181 trans = btrfs_start_transaction(root, 0);
1182 }
1183 if (IS_ERR(trans))
1184 return PTR_ERR(trans);
1185 }
1186 return btrfs_commit_transaction(trans, root);
1187 }
1188
1189 static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
1190 {
1191 struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
1192 struct btrfs_root *root = info->tree_root;
1193 char *compress_type;
1194
1195 if (btrfs_test_opt(root, DEGRADED))
1196 seq_puts(seq, ",degraded");
1197 if (btrfs_test_opt(root, NODATASUM))
1198 seq_puts(seq, ",nodatasum");
1199 if (btrfs_test_opt(root, NODATACOW))
1200 seq_puts(seq, ",nodatacow");
1201 if (btrfs_test_opt(root, NOBARRIER))
1202 seq_puts(seq, ",nobarrier");
1203 if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE)
1204 seq_printf(seq, ",max_inline=%llu", info->max_inline);
1205 if (info->alloc_start != 0)
1206 seq_printf(seq, ",alloc_start=%llu", info->alloc_start);
1207 if (info->thread_pool_size != min_t(unsigned long,
1208 num_online_cpus() + 2, 8))
1209 seq_printf(seq, ",thread_pool=%d", info->thread_pool_size);
1210 if (btrfs_test_opt(root, COMPRESS)) {
1211 if (info->compress_type == BTRFS_COMPRESS_ZLIB)
1212 compress_type = "zlib";
1213 else
1214 compress_type = "lzo";
1215 if (btrfs_test_opt(root, FORCE_COMPRESS))
1216 seq_printf(seq, ",compress-force=%s", compress_type);
1217 else
1218 seq_printf(seq, ",compress=%s", compress_type);
1219 }
1220 if (btrfs_test_opt(root, NOSSD))
1221 seq_puts(seq, ",nossd");
1222 if (btrfs_test_opt(root, SSD_SPREAD))
1223 seq_puts(seq, ",ssd_spread");
1224 else if (btrfs_test_opt(root, SSD))
1225 seq_puts(seq, ",ssd");
1226 if (btrfs_test_opt(root, NOTREELOG))
1227 seq_puts(seq, ",notreelog");
1228 if (btrfs_test_opt(root, NOLOGREPLAY))
1229 seq_puts(seq, ",nologreplay");
1230 if (btrfs_test_opt(root, FLUSHONCOMMIT))
1231 seq_puts(seq, ",flushoncommit");
1232 if (btrfs_test_opt(root, DISCARD))
1233 seq_puts(seq, ",discard");
1234 if (!(root->fs_info->sb->s_flags & MS_POSIXACL))
1235 seq_puts(seq, ",noacl");
1236 if (btrfs_test_opt(root, SPACE_CACHE))
1237 seq_puts(seq, ",space_cache");
1238 else if (btrfs_test_opt(root, FREE_SPACE_TREE))
1239 seq_puts(seq, ",space_cache=v2");
1240 else
1241 seq_puts(seq, ",nospace_cache");
1242 if (btrfs_test_opt(root, RESCAN_UUID_TREE))
1243 seq_puts(seq, ",rescan_uuid_tree");
1244 if (btrfs_test_opt(root, CLEAR_CACHE))
1245 seq_puts(seq, ",clear_cache");
1246 if (btrfs_test_opt(root, USER_SUBVOL_RM_ALLOWED))
1247 seq_puts(seq, ",user_subvol_rm_allowed");
1248 if (btrfs_test_opt(root, ENOSPC_DEBUG))
1249 seq_puts(seq, ",enospc_debug");
1250 if (btrfs_test_opt(root, AUTO_DEFRAG))
1251 seq_puts(seq, ",autodefrag");
1252 if (btrfs_test_opt(root, INODE_MAP_CACHE))
1253 seq_puts(seq, ",inode_cache");
1254 if (btrfs_test_opt(root, SKIP_BALANCE))
1255 seq_puts(seq, ",skip_balance");
1256 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
1257 if (btrfs_test_opt(root, CHECK_INTEGRITY_INCLUDING_EXTENT_DATA))
1258 seq_puts(seq, ",check_int_data");
1259 else if (btrfs_test_opt(root, CHECK_INTEGRITY))
1260 seq_puts(seq, ",check_int");
1261 if (info->check_integrity_print_mask)
1262 seq_printf(seq, ",check_int_print_mask=%d",
1263 info->check_integrity_print_mask);
1264 #endif
1265 if (info->metadata_ratio)
1266 seq_printf(seq, ",metadata_ratio=%d",
1267 info->metadata_ratio);
1268 if (btrfs_test_opt(root, PANIC_ON_FATAL_ERROR))
1269 seq_puts(seq, ",fatal_errors=panic");
1270 if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL)
1271 seq_printf(seq, ",commit=%d", info->commit_interval);
1272 #ifdef CONFIG_BTRFS_DEBUG
1273 if (btrfs_test_opt(root, FRAGMENT_DATA))
1274 seq_puts(seq, ",fragment=data");
1275 if (btrfs_test_opt(root, FRAGMENT_METADATA))
1276 seq_puts(seq, ",fragment=metadata");
1277 #endif
1278 seq_printf(seq, ",subvolid=%llu",
1279 BTRFS_I(d_inode(dentry))->root->root_key.objectid);
1280 seq_puts(seq, ",subvol=");
1281 seq_dentry(seq, dentry, " \t\n\\");
1282 return 0;
1283 }
1284
1285 static int btrfs_test_super(struct super_block *s, void *data)
1286 {
1287 struct btrfs_fs_info *p = data;
1288 struct btrfs_fs_info *fs_info = btrfs_sb(s);
1289
1290 return fs_info->fs_devices == p->fs_devices;
1291 }
1292
1293 static int btrfs_set_super(struct super_block *s, void *data)
1294 {
1295 int err = set_anon_super(s, data);
1296 if (!err)
1297 s->s_fs_info = data;
1298 return err;
1299 }
1300
1301 /*
1302 * subvolumes are identified by ino 256
1303 */
1304 static inline int is_subvolume_inode(struct inode *inode)
1305 {
1306 if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
1307 return 1;
1308 return 0;
1309 }
1310
1311 /*
1312 * This will add subvolid=0 to the argument string while removing any subvol=
1313 * and subvolid= arguments to make sure we get the top-level root for path
1314 * walking to the subvol we want.
1315 */
1316 static char *setup_root_args(char *args)
1317 {
1318 char *buf, *dst, *sep;
1319
1320 if (!args)
1321 return kstrdup("subvolid=0", GFP_NOFS);
1322
1323 /* The worst case is that we add ",subvolid=0" to the end. */
1324 buf = dst = kmalloc(strlen(args) + strlen(",subvolid=0") + 1, GFP_NOFS);
1325 if (!buf)
1326 return NULL;
1327
1328 while (1) {
1329 sep = strchrnul(args, ',');
1330 if (!strstarts(args, "subvol=") &&
1331 !strstarts(args, "subvolid=")) {
1332 memcpy(dst, args, sep - args);
1333 dst += sep - args;
1334 *dst++ = ',';
1335 }
1336 if (*sep)
1337 args = sep + 1;
1338 else
1339 break;
1340 }
1341 strcpy(dst, "subvolid=0");
1342
1343 return buf;
1344 }
1345
1346 static struct dentry *mount_subvol(const char *subvol_name, u64 subvol_objectid,
1347 int flags, const char *device_name,
1348 char *data)
1349 {
1350 struct dentry *root;
1351 struct vfsmount *mnt = NULL;
1352 char *newargs;
1353 int ret;
1354
1355 newargs = setup_root_args(data);
1356 if (!newargs) {
1357 root = ERR_PTR(-ENOMEM);
1358 goto out;
1359 }
1360
1361 mnt = vfs_kern_mount(&btrfs_fs_type, flags, device_name, newargs);
1362 if (PTR_ERR_OR_ZERO(mnt) == -EBUSY) {
1363 if (flags & MS_RDONLY) {
1364 mnt = vfs_kern_mount(&btrfs_fs_type, flags & ~MS_RDONLY,
1365 device_name, newargs);
1366 } else {
1367 mnt = vfs_kern_mount(&btrfs_fs_type, flags | MS_RDONLY,
1368 device_name, newargs);
1369 if (IS_ERR(mnt)) {
1370 root = ERR_CAST(mnt);
1371 mnt = NULL;
1372 goto out;
1373 }
1374
1375 down_write(&mnt->mnt_sb->s_umount);
1376 ret = btrfs_remount(mnt->mnt_sb, &flags, NULL);
1377 up_write(&mnt->mnt_sb->s_umount);
1378 if (ret < 0) {
1379 root = ERR_PTR(ret);
1380 goto out;
1381 }
1382 }
1383 }
1384 if (IS_ERR(mnt)) {
1385 root = ERR_CAST(mnt);
1386 mnt = NULL;
1387 goto out;
1388 }
1389
1390 if (!subvol_name) {
1391 if (!subvol_objectid) {
1392 ret = get_default_subvol_objectid(btrfs_sb(mnt->mnt_sb),
1393 &subvol_objectid);
1394 if (ret) {
1395 root = ERR_PTR(ret);
1396 goto out;
1397 }
1398 }
1399 subvol_name = get_subvol_name_from_objectid(btrfs_sb(mnt->mnt_sb),
1400 subvol_objectid);
1401 if (IS_ERR(subvol_name)) {
1402 root = ERR_CAST(subvol_name);
1403 subvol_name = NULL;
1404 goto out;
1405 }
1406
1407 }
1408
1409 root = mount_subtree(mnt, subvol_name);
1410 /* mount_subtree() drops our reference on the vfsmount. */
1411 mnt = NULL;
1412
1413 if (!IS_ERR(root)) {
1414 struct super_block *s = root->d_sb;
1415 struct inode *root_inode = d_inode(root);
1416 u64 root_objectid = BTRFS_I(root_inode)->root->root_key.objectid;
1417
1418 ret = 0;
1419 if (!is_subvolume_inode(root_inode)) {
1420 pr_err("BTRFS: '%s' is not a valid subvolume\n",
1421 subvol_name);
1422 ret = -EINVAL;
1423 }
1424 if (subvol_objectid && root_objectid != subvol_objectid) {
1425 /*
1426 * This will also catch a race condition where a
1427 * subvolume which was passed by ID is renamed and
1428 * another subvolume is renamed over the old location.
1429 */
1430 pr_err("BTRFS: subvol '%s' does not match subvolid %llu\n",
1431 subvol_name, subvol_objectid);
1432 ret = -EINVAL;
1433 }
1434 if (ret) {
1435 dput(root);
1436 root = ERR_PTR(ret);
1437 deactivate_locked_super(s);
1438 }
1439 }
1440
1441 out:
1442 mntput(mnt);
1443 kfree(newargs);
1444 kfree(subvol_name);
1445 return root;
1446 }
1447
1448 static int parse_security_options(char *orig_opts,
1449 struct security_mnt_opts *sec_opts)
1450 {
1451 char *secdata = NULL;
1452 int ret = 0;
1453
1454 secdata = alloc_secdata();
1455 if (!secdata)
1456 return -ENOMEM;
1457 ret = security_sb_copy_data(orig_opts, secdata);
1458 if (ret) {
1459 free_secdata(secdata);
1460 return ret;
1461 }
1462 ret = security_sb_parse_opts_str(secdata, sec_opts);
1463 free_secdata(secdata);
1464 return ret;
1465 }
1466
1467 static int setup_security_options(struct btrfs_fs_info *fs_info,
1468 struct super_block *sb,
1469 struct security_mnt_opts *sec_opts)
1470 {
1471 int ret = 0;
1472
1473 /*
1474 * Call security_sb_set_mnt_opts() to check whether new sec_opts
1475 * is valid.
1476 */
1477 ret = security_sb_set_mnt_opts(sb, sec_opts, 0, NULL);
1478 if (ret)
1479 return ret;
1480
1481 #ifdef CONFIG_SECURITY
1482 if (!fs_info->security_opts.num_mnt_opts) {
1483 /* first time security setup, copy sec_opts to fs_info */
1484 memcpy(&fs_info->security_opts, sec_opts, sizeof(*sec_opts));
1485 } else {
1486 /*
1487 * Since SELinux (the only one supporting security_mnt_opts)
1488 * does NOT support changing context during remount/mount of
1489 * the same sb, this must be the same or part of the same
1490 * security options, just free it.
1491 */
1492 security_free_mnt_opts(sec_opts);
1493 }
1494 #endif
1495 return ret;
1496 }
1497
1498 /*
1499 * Find a superblock for the given device / mount point.
1500 *
1501 * Note: This is based on get_sb_bdev from fs/super.c with a few additions
1502 * for multiple device setup. Make sure to keep it in sync.
1503 */
1504 static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
1505 const char *device_name, void *data)
1506 {
1507 struct block_device *bdev = NULL;
1508 struct super_block *s;
1509 struct btrfs_fs_devices *fs_devices = NULL;
1510 struct btrfs_fs_info *fs_info = NULL;
1511 struct security_mnt_opts new_sec_opts;
1512 fmode_t mode = FMODE_READ;
1513 char *subvol_name = NULL;
1514 u64 subvol_objectid = 0;
1515 int error = 0;
1516
1517 if (!(flags & MS_RDONLY))
1518 mode |= FMODE_WRITE;
1519
1520 error = btrfs_parse_early_options(data, mode, fs_type,
1521 &subvol_name, &subvol_objectid,
1522 &fs_devices);
1523 if (error) {
1524 kfree(subvol_name);
1525 return ERR_PTR(error);
1526 }
1527
1528 if (subvol_name || subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
1529 /* mount_subvol() will free subvol_name. */
1530 return mount_subvol(subvol_name, subvol_objectid, flags,
1531 device_name, data);
1532 }
1533
1534 security_init_mnt_opts(&new_sec_opts);
1535 if (data) {
1536 error = parse_security_options(data, &new_sec_opts);
1537 if (error)
1538 return ERR_PTR(error);
1539 }
1540
1541 error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices);
1542 if (error)
1543 goto error_sec_opts;
1544
1545 /*
1546 * Setup a dummy root and fs_info for test/set super. This is because
1547 * we don't actually fill this stuff out until open_ctree, but we need
1548 * it for searching for existing supers, so this lets us do that and
1549 * then open_ctree will properly initialize everything later.
1550 */
1551 fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_NOFS);
1552 if (!fs_info) {
1553 error = -ENOMEM;
1554 goto error_sec_opts;
1555 }
1556
1557 fs_info->fs_devices = fs_devices;
1558
1559 fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
1560 fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
1561 security_init_mnt_opts(&fs_info->security_opts);
1562 if (!fs_info->super_copy || !fs_info->super_for_commit) {
1563 error = -ENOMEM;
1564 goto error_fs_info;
1565 }
1566
1567 error = btrfs_open_devices(fs_devices, mode, fs_type);
1568 if (error)
1569 goto error_fs_info;
1570
1571 if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
1572 error = -EACCES;
1573 goto error_close_devices;
1574 }
1575
1576 bdev = fs_devices->latest_bdev;
1577 s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | MS_NOSEC,
1578 fs_info);
1579 if (IS_ERR(s)) {
1580 error = PTR_ERR(s);
1581 goto error_close_devices;
1582 }
1583
1584 if (s->s_root) {
1585 btrfs_close_devices(fs_devices);
1586 free_fs_info(fs_info);
1587 if ((flags ^ s->s_flags) & MS_RDONLY)
1588 error = -EBUSY;
1589 } else {
1590 snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev);
1591 btrfs_sb(s)->bdev_holder = fs_type;
1592 error = btrfs_fill_super(s, fs_devices, data,
1593 flags & MS_SILENT ? 1 : 0);
1594 }
1595 if (error) {
1596 deactivate_locked_super(s);
1597 goto error_sec_opts;
1598 }
1599
1600 fs_info = btrfs_sb(s);
1601 error = setup_security_options(fs_info, s, &new_sec_opts);
1602 if (error) {
1603 deactivate_locked_super(s);
1604 goto error_sec_opts;
1605 }
1606
1607 return dget(s->s_root);
1608
1609 error_close_devices:
1610 btrfs_close_devices(fs_devices);
1611 error_fs_info:
1612 free_fs_info(fs_info);
1613 error_sec_opts:
1614 security_free_mnt_opts(&new_sec_opts);
1615 return ERR_PTR(error);
1616 }
1617
1618 static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
1619 int new_pool_size, int old_pool_size)
1620 {
1621 if (new_pool_size == old_pool_size)
1622 return;
1623
1624 fs_info->thread_pool_size = new_pool_size;
1625
1626 btrfs_info(fs_info, "resize thread pool %d -> %d",
1627 old_pool_size, new_pool_size);
1628
1629 btrfs_workqueue_set_max(fs_info->workers, new_pool_size);
1630 btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size);
1631 btrfs_workqueue_set_max(fs_info->submit_workers, new_pool_size);
1632 btrfs_workqueue_set_max(fs_info->caching_workers, new_pool_size);
1633 btrfs_workqueue_set_max(fs_info->endio_workers, new_pool_size);
1634 btrfs_workqueue_set_max(fs_info->endio_meta_workers, new_pool_size);
1635 btrfs_workqueue_set_max(fs_info->endio_meta_write_workers,
1636 new_pool_size);
1637 btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size);
1638 btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
1639 btrfs_workqueue_set_max(fs_info->delayed_workers, new_pool_size);
1640 btrfs_workqueue_set_max(fs_info->readahead_workers, new_pool_size);
1641 btrfs_workqueue_set_max(fs_info->scrub_wr_completion_workers,
1642 new_pool_size);
1643 }
1644
1645 static inline void btrfs_remount_prepare(struct btrfs_fs_info *fs_info)
1646 {
1647 set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1648 }
1649
1650 static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info,
1651 unsigned long old_opts, int flags)
1652 {
1653 if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1654 (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1655 (flags & MS_RDONLY))) {
1656 /* wait for any defraggers to finish */
1657 wait_event(fs_info->transaction_wait,
1658 (atomic_read(&fs_info->defrag_running) == 0));
1659 if (flags & MS_RDONLY)
1660 sync_filesystem(fs_info->sb);
1661 }
1662 }
1663
1664 static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
1665 unsigned long old_opts)
1666 {
1667 /*
1668 * We need to cleanup all defragable inodes if the autodefragment is
1669 * close or the filesystem is read only.
1670 */
1671 if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1672 (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1673 (fs_info->sb->s_flags & MS_RDONLY))) {
1674 btrfs_cleanup_defrag_inodes(fs_info);
1675 }
1676
1677 clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1678 }
1679
1680 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
1681 {
1682 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1683 struct btrfs_root *root = fs_info->tree_root;
1684 unsigned old_flags = sb->s_flags;
1685 unsigned long old_opts = fs_info->mount_opt;
1686 unsigned long old_compress_type = fs_info->compress_type;
1687 u64 old_max_inline = fs_info->max_inline;
1688 u64 old_alloc_start = fs_info->alloc_start;
1689 int old_thread_pool_size = fs_info->thread_pool_size;
1690 unsigned int old_metadata_ratio = fs_info->metadata_ratio;
1691 int ret;
1692
1693 sync_filesystem(sb);
1694 btrfs_remount_prepare(fs_info);
1695
1696 if (data) {
1697 struct security_mnt_opts new_sec_opts;
1698
1699 security_init_mnt_opts(&new_sec_opts);
1700 ret = parse_security_options(data, &new_sec_opts);
1701 if (ret)
1702 goto restore;
1703 ret = setup_security_options(fs_info, sb,
1704 &new_sec_opts);
1705 if (ret) {
1706 security_free_mnt_opts(&new_sec_opts);
1707 goto restore;
1708 }
1709 }
1710
1711 ret = btrfs_parse_options(root, data, *flags);
1712 if (ret) {
1713 ret = -EINVAL;
1714 goto restore;
1715 }
1716
1717 btrfs_remount_begin(fs_info, old_opts, *flags);
1718 btrfs_resize_thread_pool(fs_info,
1719 fs_info->thread_pool_size, old_thread_pool_size);
1720
1721 if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1722 goto out;
1723
1724 if (*flags & MS_RDONLY) {
1725 /*
1726 * this also happens on 'umount -rf' or on shutdown, when
1727 * the filesystem is busy.
1728 */
1729 cancel_work_sync(&fs_info->async_reclaim_work);
1730
1731 /* wait for the uuid_scan task to finish */
1732 down(&fs_info->uuid_tree_rescan_sem);
1733 /* avoid complains from lockdep et al. */
1734 up(&fs_info->uuid_tree_rescan_sem);
1735
1736 sb->s_flags |= MS_RDONLY;
1737
1738 /*
1739 * Setting MS_RDONLY will put the cleaner thread to
1740 * sleep at the next loop if it's already active.
1741 * If it's already asleep, we'll leave unused block
1742 * groups on disk until we're mounted read-write again
1743 * unless we clean them up here.
1744 */
1745 btrfs_delete_unused_bgs(fs_info);
1746
1747 btrfs_dev_replace_suspend_for_unmount(fs_info);
1748 btrfs_scrub_cancel(fs_info);
1749 btrfs_pause_balance(fs_info);
1750
1751 ret = btrfs_commit_super(root);
1752 if (ret)
1753 goto restore;
1754 } else {
1755 if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state)) {
1756 btrfs_err(fs_info,
1757 "Remounting read-write after error is not allowed");
1758 ret = -EINVAL;
1759 goto restore;
1760 }
1761 if (fs_info->fs_devices->rw_devices == 0) {
1762 ret = -EACCES;
1763 goto restore;
1764 }
1765
1766 if (fs_info->fs_devices->missing_devices >
1767 fs_info->num_tolerated_disk_barrier_failures &&
1768 !(*flags & MS_RDONLY)) {
1769 btrfs_warn(fs_info,
1770 "too many missing devices, writeable remount is not allowed");
1771 ret = -EACCES;
1772 goto restore;
1773 }
1774
1775 if (btrfs_super_log_root(fs_info->super_copy) != 0) {
1776 ret = -EINVAL;
1777 goto restore;
1778 }
1779
1780 ret = btrfs_cleanup_fs_roots(fs_info);
1781 if (ret)
1782 goto restore;
1783
1784 /* recover relocation */
1785 mutex_lock(&fs_info->cleaner_mutex);
1786 ret = btrfs_recover_relocation(root);
1787 mutex_unlock(&fs_info->cleaner_mutex);
1788 if (ret)
1789 goto restore;
1790
1791 ret = btrfs_resume_balance_async(fs_info);
1792 if (ret)
1793 goto restore;
1794
1795 ret = btrfs_resume_dev_replace_async(fs_info);
1796 if (ret) {
1797 btrfs_warn(fs_info, "failed to resume dev_replace");
1798 goto restore;
1799 }
1800
1801 if (!fs_info->uuid_root) {
1802 btrfs_info(fs_info, "creating UUID tree");
1803 ret = btrfs_create_uuid_tree(fs_info);
1804 if (ret) {
1805 btrfs_warn(fs_info, "failed to create the UUID tree %d", ret);
1806 goto restore;
1807 }
1808 }
1809 sb->s_flags &= ~MS_RDONLY;
1810 }
1811 out:
1812 wake_up_process(fs_info->transaction_kthread);
1813 btrfs_remount_cleanup(fs_info, old_opts);
1814 return 0;
1815
1816 restore:
1817 /* We've hit an error - don't reset MS_RDONLY */
1818 if (sb->s_flags & MS_RDONLY)
1819 old_flags |= MS_RDONLY;
1820 sb->s_flags = old_flags;
1821 fs_info->mount_opt = old_opts;
1822 fs_info->compress_type = old_compress_type;
1823 fs_info->max_inline = old_max_inline;
1824 mutex_lock(&fs_info->chunk_mutex);
1825 fs_info->alloc_start = old_alloc_start;
1826 mutex_unlock(&fs_info->chunk_mutex);
1827 btrfs_resize_thread_pool(fs_info,
1828 old_thread_pool_size, fs_info->thread_pool_size);
1829 fs_info->metadata_ratio = old_metadata_ratio;
1830 btrfs_remount_cleanup(fs_info, old_opts);
1831 return ret;
1832 }
1833
1834 /* Used to sort the devices by max_avail(descending sort) */
1835 static int btrfs_cmp_device_free_bytes(const void *dev_info1,
1836 const void *dev_info2)
1837 {
1838 if (((struct btrfs_device_info *)dev_info1)->max_avail >
1839 ((struct btrfs_device_info *)dev_info2)->max_avail)
1840 return -1;
1841 else if (((struct btrfs_device_info *)dev_info1)->max_avail <
1842 ((struct btrfs_device_info *)dev_info2)->max_avail)
1843 return 1;
1844 else
1845 return 0;
1846 }
1847
1848 /*
1849 * sort the devices by max_avail, in which max free extent size of each device
1850 * is stored.(Descending Sort)
1851 */
1852 static inline void btrfs_descending_sort_devices(
1853 struct btrfs_device_info *devices,
1854 size_t nr_devices)
1855 {
1856 sort(devices, nr_devices, sizeof(struct btrfs_device_info),
1857 btrfs_cmp_device_free_bytes, NULL);
1858 }
1859
1860 /*
1861 * The helper to calc the free space on the devices that can be used to store
1862 * file data.
1863 */
1864 static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes)
1865 {
1866 struct btrfs_fs_info *fs_info = root->fs_info;
1867 struct btrfs_device_info *devices_info;
1868 struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
1869 struct btrfs_device *device;
1870 u64 skip_space;
1871 u64 type;
1872 u64 avail_space;
1873 u64 used_space;
1874 u64 min_stripe_size;
1875 int min_stripes = 1, num_stripes = 1;
1876 int i = 0, nr_devices;
1877 int ret;
1878
1879 /*
1880 * We aren't under the device list lock, so this is racy-ish, but good
1881 * enough for our purposes.
1882 */
1883 nr_devices = fs_info->fs_devices->open_devices;
1884 if (!nr_devices) {
1885 smp_mb();
1886 nr_devices = fs_info->fs_devices->open_devices;
1887 ASSERT(nr_devices);
1888 if (!nr_devices) {
1889 *free_bytes = 0;
1890 return 0;
1891 }
1892 }
1893
1894 devices_info = kmalloc_array(nr_devices, sizeof(*devices_info),
1895 GFP_NOFS);
1896 if (!devices_info)
1897 return -ENOMEM;
1898
1899 /* calc min stripe number for data space allocation */
1900 type = btrfs_get_alloc_profile(root, 1);
1901 if (type & BTRFS_BLOCK_GROUP_RAID0) {
1902 min_stripes = 2;
1903 num_stripes = nr_devices;
1904 } else if (type & BTRFS_BLOCK_GROUP_RAID1) {
1905 min_stripes = 2;
1906 num_stripes = 2;
1907 } else if (type & BTRFS_BLOCK_GROUP_RAID10) {
1908 min_stripes = 4;
1909 num_stripes = 4;
1910 }
1911
1912 if (type & BTRFS_BLOCK_GROUP_DUP)
1913 min_stripe_size = 2 * BTRFS_STRIPE_LEN;
1914 else
1915 min_stripe_size = BTRFS_STRIPE_LEN;
1916
1917 if (fs_info->alloc_start)
1918 mutex_lock(&fs_devices->device_list_mutex);
1919 rcu_read_lock();
1920 list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
1921 if (!device->in_fs_metadata || !device->bdev ||
1922 device->is_tgtdev_for_dev_replace)
1923 continue;
1924
1925 if (i >= nr_devices)
1926 break;
1927
1928 avail_space = device->total_bytes - device->bytes_used;
1929
1930 /* align with stripe_len */
1931 avail_space = div_u64(avail_space, BTRFS_STRIPE_LEN);
1932 avail_space *= BTRFS_STRIPE_LEN;
1933
1934 /*
1935 * In order to avoid overwriting the superblock on the drive,
1936 * btrfs starts at an offset of at least 1MB when doing chunk
1937 * allocation.
1938 */
1939 skip_space = SZ_1M;
1940
1941 /* user can set the offset in fs_info->alloc_start. */
1942 if (fs_info->alloc_start &&
1943 fs_info->alloc_start + BTRFS_STRIPE_LEN <=
1944 device->total_bytes) {
1945 rcu_read_unlock();
1946 skip_space = max(fs_info->alloc_start, skip_space);
1947
1948 /*
1949 * btrfs can not use the free space in
1950 * [0, skip_space - 1], we must subtract it from the
1951 * total. In order to implement it, we account the used
1952 * space in this range first.
1953 */
1954 ret = btrfs_account_dev_extents_size(device, 0,
1955 skip_space - 1,
1956 &used_space);
1957 if (ret) {
1958 kfree(devices_info);
1959 mutex_unlock(&fs_devices->device_list_mutex);
1960 return ret;
1961 }
1962
1963 rcu_read_lock();
1964
1965 /* calc the free space in [0, skip_space - 1] */
1966 skip_space -= used_space;
1967 }
1968
1969 /*
1970 * we can use the free space in [0, skip_space - 1], subtract
1971 * it from the total.
1972 */
1973 if (avail_space && avail_space >= skip_space)
1974 avail_space -= skip_space;
1975 else
1976 avail_space = 0;
1977
1978 if (avail_space < min_stripe_size)
1979 continue;
1980
1981 devices_info[i].dev = device;
1982 devices_info[i].max_avail = avail_space;
1983
1984 i++;
1985 }
1986 rcu_read_unlock();
1987 if (fs_info->alloc_start)
1988 mutex_unlock(&fs_devices->device_list_mutex);
1989
1990 nr_devices = i;
1991
1992 btrfs_descending_sort_devices(devices_info, nr_devices);
1993
1994 i = nr_devices - 1;
1995 avail_space = 0;
1996 while (nr_devices >= min_stripes) {
1997 if (num_stripes > nr_devices)
1998 num_stripes = nr_devices;
1999
2000 if (devices_info[i].max_avail >= min_stripe_size) {
2001 int j;
2002 u64 alloc_size;
2003
2004 avail_space += devices_info[i].max_avail * num_stripes;
2005 alloc_size = devices_info[i].max_avail;
2006 for (j = i + 1 - num_stripes; j <= i; j++)
2007 devices_info[j].max_avail -= alloc_size;
2008 }
2009 i--;
2010 nr_devices--;
2011 }
2012
2013 kfree(devices_info);
2014 *free_bytes = avail_space;
2015 return 0;
2016 }
2017
2018 /*
2019 * Calculate numbers for 'df', pessimistic in case of mixed raid profiles.
2020 *
2021 * If there's a redundant raid level at DATA block groups, use the respective
2022 * multiplier to scale the sizes.
2023 *
2024 * Unused device space usage is based on simulating the chunk allocator
2025 * algorithm that respects the device sizes, order of allocations and the
2026 * 'alloc_start' value, this is a close approximation of the actual use but
2027 * there are other factors that may change the result (like a new metadata
2028 * chunk).
2029 *
2030 * If metadata is exhausted, f_bavail will be 0.
2031 *
2032 * FIXME: not accurate for mixed block groups, total and free/used are ok,
2033 * available appears slightly larger.
2034 */
2035 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
2036 {
2037 struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
2038 struct btrfs_super_block *disk_super = fs_info->super_copy;
2039 struct list_head *head = &fs_info->space_info;
2040 struct btrfs_space_info *found;
2041 u64 total_used = 0;
2042 u64 total_free_data = 0;
2043 u64 total_free_meta = 0;
2044 int bits = dentry->d_sb->s_blocksize_bits;
2045 __be32 *fsid = (__be32 *)fs_info->fsid;
2046 unsigned factor = 1;
2047 struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
2048 int ret;
2049 u64 thresh = 0;
2050 int mixed = 0;
2051
2052 /*
2053 * holding chunk_mutex to avoid allocating new chunks, holding
2054 * device_list_mutex to avoid the device being removed
2055 */
2056 rcu_read_lock();
2057 list_for_each_entry_rcu(found, head, list) {
2058 if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
2059 int i;
2060
2061 total_free_data += found->disk_total - found->disk_used;
2062 total_free_data -=
2063 btrfs_account_ro_block_groups_free_space(found);
2064
2065 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
2066 if (!list_empty(&found->block_groups[i])) {
2067 switch (i) {
2068 case BTRFS_RAID_DUP:
2069 case BTRFS_RAID_RAID1:
2070 case BTRFS_RAID_RAID10:
2071 factor = 2;
2072 }
2073 }
2074 }
2075 }
2076
2077 /*
2078 * Metadata in mixed block goup profiles are accounted in data
2079 */
2080 if (!mixed && found->flags & BTRFS_BLOCK_GROUP_METADATA) {
2081 if (found->flags & BTRFS_BLOCK_GROUP_DATA)
2082 mixed = 1;
2083 else
2084 total_free_meta += found->disk_total -
2085 found->disk_used;
2086 }
2087
2088 total_used += found->disk_used;
2089 }
2090
2091 rcu_read_unlock();
2092
2093 buf->f_blocks = div_u64(btrfs_super_total_bytes(disk_super), factor);
2094 buf->f_blocks >>= bits;
2095 buf->f_bfree = buf->f_blocks - (div_u64(total_used, factor) >> bits);
2096
2097 /* Account global block reserve as used, it's in logical size already */
2098 spin_lock(&block_rsv->lock);
2099 /* Mixed block groups accounting is not byte-accurate, avoid overflow */
2100 if (buf->f_bfree >= block_rsv->size >> bits)
2101 buf->f_bfree -= block_rsv->size >> bits;
2102 else
2103 buf->f_bfree = 0;
2104 spin_unlock(&block_rsv->lock);
2105
2106 buf->f_bavail = div_u64(total_free_data, factor);
2107 ret = btrfs_calc_avail_data_space(fs_info->tree_root, &total_free_data);
2108 if (ret)
2109 return ret;
2110 buf->f_bavail += div_u64(total_free_data, factor);
2111 buf->f_bavail = buf->f_bavail >> bits;
2112
2113 /*
2114 * We calculate the remaining metadata space minus global reserve. If
2115 * this is (supposedly) smaller than zero, there's no space. But this
2116 * does not hold in practice, the exhausted state happens where's still
2117 * some positive delta. So we apply some guesswork and compare the
2118 * delta to a 4M threshold. (Practically observed delta was ~2M.)
2119 *
2120 * We probably cannot calculate the exact threshold value because this
2121 * depends on the internal reservations requested by various
2122 * operations, so some operations that consume a few metadata will
2123 * succeed even if the Avail is zero. But this is better than the other
2124 * way around.
2125 */
2126 thresh = 4 * 1024 * 1024;
2127
2128 if (!mixed && total_free_meta - thresh < block_rsv->size)
2129 buf->f_bavail = 0;
2130
2131 buf->f_type = BTRFS_SUPER_MAGIC;
2132 buf->f_bsize = dentry->d_sb->s_blocksize;
2133 buf->f_namelen = BTRFS_NAME_LEN;
2134
2135 /* We treat it as constant endianness (it doesn't matter _which_)
2136 because we want the fsid to come out the same whether mounted
2137 on a big-endian or little-endian host */
2138 buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
2139 buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
2140 /* Mask in the root object ID too, to disambiguate subvols */
2141 buf->f_fsid.val[0] ^= BTRFS_I(d_inode(dentry))->root->objectid >> 32;
2142 buf->f_fsid.val[1] ^= BTRFS_I(d_inode(dentry))->root->objectid;
2143
2144 return 0;
2145 }
2146
2147 static void btrfs_kill_super(struct super_block *sb)
2148 {
2149 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2150 kill_anon_super(sb);
2151 free_fs_info(fs_info);
2152 }
2153
2154 static struct file_system_type btrfs_fs_type = {
2155 .owner = THIS_MODULE,
2156 .name = "btrfs",
2157 .mount = btrfs_mount,
2158 .kill_sb = btrfs_kill_super,
2159 .fs_flags = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,
2160 };
2161 MODULE_ALIAS_FS("btrfs");
2162
2163 static int btrfs_control_open(struct inode *inode, struct file *file)
2164 {
2165 /*
2166 * The control file's private_data is used to hold the
2167 * transaction when it is started and is used to keep
2168 * track of whether a transaction is already in progress.
2169 */
2170 file->private_data = NULL;
2171 return 0;
2172 }
2173
2174 /*
2175 * used by btrfsctl to scan devices when no FS is mounted
2176 */
2177 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
2178 unsigned long arg)
2179 {
2180 struct btrfs_ioctl_vol_args *vol;
2181 struct btrfs_fs_devices *fs_devices;
2182 int ret = -ENOTTY;
2183
2184 if (!capable(CAP_SYS_ADMIN))
2185 return -EPERM;
2186
2187 vol = memdup_user((void __user *)arg, sizeof(*vol));
2188 if (IS_ERR(vol))
2189 return PTR_ERR(vol);
2190
2191 switch (cmd) {
2192 case BTRFS_IOC_SCAN_DEV:
2193 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
2194 &btrfs_fs_type, &fs_devices);
2195 break;
2196 case BTRFS_IOC_DEVICES_READY:
2197 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
2198 &btrfs_fs_type, &fs_devices);
2199 if (ret)
2200 break;
2201 ret = !(fs_devices->num_devices == fs_devices->total_devices);
2202 break;
2203 case BTRFS_IOC_GET_SUPPORTED_FEATURES:
2204 ret = btrfs_ioctl_get_supported_features((void __user*)arg);
2205 break;
2206 }
2207
2208 kfree(vol);
2209 return ret;
2210 }
2211
2212 static int btrfs_freeze(struct super_block *sb)
2213 {
2214 struct btrfs_trans_handle *trans;
2215 struct btrfs_root *root = btrfs_sb(sb)->tree_root;
2216
2217 trans = btrfs_attach_transaction_barrier(root);
2218 if (IS_ERR(trans)) {
2219 /* no transaction, don't bother */
2220 if (PTR_ERR(trans) == -ENOENT)
2221 return 0;
2222 return PTR_ERR(trans);
2223 }
2224 return btrfs_commit_transaction(trans, root);
2225 }
2226
2227 static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
2228 {
2229 struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
2230 struct btrfs_fs_devices *cur_devices;
2231 struct btrfs_device *dev, *first_dev = NULL;
2232 struct list_head *head;
2233 struct rcu_string *name;
2234
2235 mutex_lock(&fs_info->fs_devices->device_list_mutex);
2236 cur_devices = fs_info->fs_devices;
2237 while (cur_devices) {
2238 head = &cur_devices->devices;
2239 list_for_each_entry(dev, head, dev_list) {
2240 if (dev->missing)
2241 continue;
2242 if (!dev->name)
2243 continue;
2244 if (!first_dev || dev->devid < first_dev->devid)
2245 first_dev = dev;
2246 }
2247 cur_devices = cur_devices->seed;
2248 }
2249
2250 if (first_dev) {
2251 rcu_read_lock();
2252 name = rcu_dereference(first_dev->name);
2253 seq_escape(m, name->str, " \t\n\\");
2254 rcu_read_unlock();
2255 } else {
2256 WARN_ON(1);
2257 }
2258 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2259 return 0;
2260 }
2261
2262 static const struct super_operations btrfs_super_ops = {
2263 .drop_inode = btrfs_drop_inode,
2264 .evict_inode = btrfs_evict_inode,
2265 .put_super = btrfs_put_super,
2266 .sync_fs = btrfs_sync_fs,
2267 .show_options = btrfs_show_options,
2268 .show_devname = btrfs_show_devname,
2269 .write_inode = btrfs_write_inode,
2270 .alloc_inode = btrfs_alloc_inode,
2271 .destroy_inode = btrfs_destroy_inode,
2272 .statfs = btrfs_statfs,
2273 .remount_fs = btrfs_remount,
2274 .freeze_fs = btrfs_freeze,
2275 };
2276
2277 static const struct file_operations btrfs_ctl_fops = {
2278 .open = btrfs_control_open,
2279 .unlocked_ioctl = btrfs_control_ioctl,
2280 .compat_ioctl = btrfs_control_ioctl,
2281 .owner = THIS_MODULE,
2282 .llseek = noop_llseek,
2283 };
2284
2285 static struct miscdevice btrfs_misc = {
2286 .minor = BTRFS_MINOR,
2287 .name = "btrfs-control",
2288 .fops = &btrfs_ctl_fops
2289 };
2290
2291 MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
2292 MODULE_ALIAS("devname:btrfs-control");
2293
2294 static int btrfs_interface_init(void)
2295 {
2296 return misc_register(&btrfs_misc);
2297 }
2298
2299 static void btrfs_interface_exit(void)
2300 {
2301 misc_deregister(&btrfs_misc);
2302 }
2303
2304 static void btrfs_print_mod_info(void)
2305 {
2306 printk(KERN_INFO "Btrfs loaded"
2307 #ifdef CONFIG_BTRFS_DEBUG
2308 ", debug=on"
2309 #endif
2310 #ifdef CONFIG_BTRFS_ASSERT
2311 ", assert=on"
2312 #endif
2313 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
2314 ", integrity-checker=on"
2315 #endif
2316 "\n");
2317 }
2318
2319 static int btrfs_run_sanity_tests(void)
2320 {
2321 int ret;
2322
2323 ret = btrfs_init_test_fs();
2324 if (ret)
2325 return ret;
2326
2327 ret = btrfs_test_free_space_cache();
2328 if (ret)
2329 goto out;
2330 ret = btrfs_test_extent_buffer_operations();
2331 if (ret)
2332 goto out;
2333 ret = btrfs_test_extent_io();
2334 if (ret)
2335 goto out;
2336 ret = btrfs_test_inodes();
2337 if (ret)
2338 goto out;
2339 ret = btrfs_test_qgroups();
2340 if (ret)
2341 goto out;
2342 ret = btrfs_test_free_space_tree();
2343 out:
2344 btrfs_destroy_test_fs();
2345 return ret;
2346 }
2347
2348 static int __init init_btrfs_fs(void)
2349 {
2350 int err;
2351
2352 err = btrfs_hash_init();
2353 if (err)
2354 return err;
2355
2356 btrfs_props_init();
2357
2358 err = btrfs_init_sysfs();
2359 if (err)
2360 goto free_hash;
2361
2362 btrfs_init_compress();
2363
2364 err = btrfs_init_cachep();
2365 if (err)
2366 goto free_compress;
2367
2368 err = extent_io_init();
2369 if (err)
2370 goto free_cachep;
2371
2372 err = extent_map_init();
2373 if (err)
2374 goto free_extent_io;
2375
2376 err = ordered_data_init();
2377 if (err)
2378 goto free_extent_map;
2379
2380 err = btrfs_delayed_inode_init();
2381 if (err)
2382 goto free_ordered_data;
2383
2384 err = btrfs_auto_defrag_init();
2385 if (err)
2386 goto free_delayed_inode;
2387
2388 err = btrfs_delayed_ref_init();
2389 if (err)
2390 goto free_auto_defrag;
2391
2392 err = btrfs_prelim_ref_init();
2393 if (err)
2394 goto free_delayed_ref;
2395
2396 err = btrfs_end_io_wq_init();
2397 if (err)
2398 goto free_prelim_ref;
2399
2400 err = btrfs_interface_init();
2401 if (err)
2402 goto free_end_io_wq;
2403
2404 btrfs_init_lockdep();
2405
2406 btrfs_print_mod_info();
2407
2408 err = btrfs_run_sanity_tests();
2409 if (err)
2410 goto unregister_ioctl;
2411
2412 err = register_filesystem(&btrfs_fs_type);
2413 if (err)
2414 goto unregister_ioctl;
2415
2416 return 0;
2417
2418 unregister_ioctl:
2419 btrfs_interface_exit();
2420 free_end_io_wq:
2421 btrfs_end_io_wq_exit();
2422 free_prelim_ref:
2423 btrfs_prelim_ref_exit();
2424 free_delayed_ref:
2425 btrfs_delayed_ref_exit();
2426 free_auto_defrag:
2427 btrfs_auto_defrag_exit();
2428 free_delayed_inode:
2429 btrfs_delayed_inode_exit();
2430 free_ordered_data:
2431 ordered_data_exit();
2432 free_extent_map:
2433 extent_map_exit();
2434 free_extent_io:
2435 extent_io_exit();
2436 free_cachep:
2437 btrfs_destroy_cachep();
2438 free_compress:
2439 btrfs_exit_compress();
2440 btrfs_exit_sysfs();
2441 free_hash:
2442 btrfs_hash_exit();
2443 return err;
2444 }
2445
2446 static void __exit exit_btrfs_fs(void)
2447 {
2448 btrfs_destroy_cachep();
2449 btrfs_delayed_ref_exit();
2450 btrfs_auto_defrag_exit();
2451 btrfs_delayed_inode_exit();
2452 btrfs_prelim_ref_exit();
2453 ordered_data_exit();
2454 extent_map_exit();
2455 extent_io_exit();
2456 btrfs_interface_exit();
2457 btrfs_end_io_wq_exit();
2458 unregister_filesystem(&btrfs_fs_type);
2459 btrfs_exit_sysfs();
2460 btrfs_cleanup_fs_uuids();
2461 btrfs_exit_compress();
2462 btrfs_hash_exit();
2463 }
2464
2465 late_initcall(init_btrfs_fs);
2466 module_exit(exit_btrfs_fs)
2467
2468 MODULE_LICENSE("GPL");
Linux with added FPC-III support