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i2c: i2c-core: sort includes
[linux-2.6/btrfs-unstable.git] / fs / btrfs / super.c
blobd41e09fe8e38d77674862c7fe61f610a81d1159d
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 enum btrfs_compression_type saved_compress_type;
387 bool saved_compress_force;
388 int no_compress = 0;
389
390 cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
391 if (btrfs_fs_compat_ro(root->fs_info, FREE_SPACE_TREE))
392 btrfs_set_opt(info->mount_opt, FREE_SPACE_TREE);
393 else if (cache_gen)
394 btrfs_set_opt(info->mount_opt, SPACE_CACHE);
395
396 if (!options)
397 goto out;
398
399 /*
400 * strsep changes the string, duplicate it because parse_options
401 * gets called twice
402 */
403 options = kstrdup(options, GFP_NOFS);
404 if (!options)
405 return -ENOMEM;
406
407 orig = options;
408
409 while ((p = strsep(&options, ",")) != NULL) {
410 int token;
411 if (!*p)
412 continue;
413
414 token = match_token(p, tokens, args);
415 switch (token) {
416 case Opt_degraded:
417 btrfs_info(root->fs_info, "allowing degraded mounts");
418 btrfs_set_opt(info->mount_opt, DEGRADED);
419 break;
420 case Opt_subvol:
421 case Opt_subvolid:
422 case Opt_subvolrootid:
423 case Opt_device:
424 /*
425 * These are parsed by btrfs_parse_early_options
426 * and can be happily ignored here.
427 */
428 break;
429 case Opt_nodatasum:
430 btrfs_set_and_info(root, NODATASUM,
431 "setting nodatasum");
432 break;
433 case Opt_datasum:
434 if (btrfs_test_opt(root, NODATASUM)) {
435 if (btrfs_test_opt(root, NODATACOW))
436 btrfs_info(root->fs_info, "setting datasum, datacow enabled");
437 else
438 btrfs_info(root->fs_info, "setting datasum");
439 }
440 btrfs_clear_opt(info->mount_opt, NODATACOW);
441 btrfs_clear_opt(info->mount_opt, NODATASUM);
442 break;
443 case Opt_nodatacow:
444 if (!btrfs_test_opt(root, NODATACOW)) {
445 if (!btrfs_test_opt(root, COMPRESS) ||
446 !btrfs_test_opt(root, FORCE_COMPRESS)) {
447 btrfs_info(root->fs_info,
448 "setting nodatacow, compression disabled");
449 } else {
450 btrfs_info(root->fs_info, "setting nodatacow");
451 }
452 }
453 btrfs_clear_opt(info->mount_opt, COMPRESS);
454 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
455 btrfs_set_opt(info->mount_opt, NODATACOW);
456 btrfs_set_opt(info->mount_opt, NODATASUM);
457 break;
458 case Opt_datacow:
459 btrfs_clear_and_info(root, NODATACOW,
460 "setting datacow");
461 break;
462 case Opt_compress_force:
463 case Opt_compress_force_type:
464 compress_force = true;
465 /* Fallthrough */
466 case Opt_compress:
467 case Opt_compress_type:
468 saved_compress_type = btrfs_test_opt(root, COMPRESS) ?
469 info->compress_type : BTRFS_COMPRESS_NONE;
470 saved_compress_force =
471 btrfs_test_opt(root, FORCE_COMPRESS);
472 if (token == Opt_compress ||
473 token == Opt_compress_force ||
474 strcmp(args[0].from, "zlib") == 0) {
475 compress_type = "zlib";
476 info->compress_type = BTRFS_COMPRESS_ZLIB;
477 btrfs_set_opt(info->mount_opt, COMPRESS);
478 btrfs_clear_opt(info->mount_opt, NODATACOW);
479 btrfs_clear_opt(info->mount_opt, NODATASUM);
480 no_compress = 0;
481 } else if (strcmp(args[0].from, "lzo") == 0) {
482 compress_type = "lzo";
483 info->compress_type = BTRFS_COMPRESS_LZO;
484 btrfs_set_opt(info->mount_opt, COMPRESS);
485 btrfs_clear_opt(info->mount_opt, NODATACOW);
486 btrfs_clear_opt(info->mount_opt, NODATASUM);
487 btrfs_set_fs_incompat(info, COMPRESS_LZO);
488 no_compress = 0;
489 } else if (strncmp(args[0].from, "no", 2) == 0) {
490 compress_type = "no";
491 btrfs_clear_opt(info->mount_opt, COMPRESS);
492 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
493 compress_force = false;
494 no_compress++;
495 } else {
496 ret = -EINVAL;
497 goto out;
498 }
499
500 if (compress_force) {
501 btrfs_set_opt(info->mount_opt, FORCE_COMPRESS);
502 } else {
503 /*
504 * If we remount from compress-force=xxx to
505 * compress=xxx, we need clear FORCE_COMPRESS
506 * flag, otherwise, there is no way for users
507 * to disable forcible compression separately.
508 */
509 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
510 }
511 if ((btrfs_test_opt(root, COMPRESS) &&
512 (info->compress_type != saved_compress_type ||
513 compress_force != saved_compress_force)) ||
514 (!btrfs_test_opt(root, COMPRESS) &&
515 no_compress == 1)) {
516 btrfs_info(root->fs_info,
517 "%s %s compression",
518 (compress_force) ? "force" : "use",
519 compress_type);
520 }
521 compress_force = false;
522 break;
523 case Opt_ssd:
524 btrfs_set_and_info(root, SSD,
525 "use ssd allocation scheme");
526 break;
527 case Opt_ssd_spread:
528 btrfs_set_and_info(root, SSD_SPREAD,
529 "use spread ssd allocation scheme");
530 btrfs_set_opt(info->mount_opt, SSD);
531 break;
532 case Opt_nossd:
533 btrfs_set_and_info(root, NOSSD,
534 "not using ssd allocation scheme");
535 btrfs_clear_opt(info->mount_opt, SSD);
536 break;
537 case Opt_barrier:
538 btrfs_clear_and_info(root, NOBARRIER,
539 "turning on barriers");
540 break;
541 case Opt_nobarrier:
542 btrfs_set_and_info(root, NOBARRIER,
543 "turning off barriers");
544 break;
545 case Opt_thread_pool:
546 ret = match_int(&args[0], &intarg);
547 if (ret) {
548 goto out;
549 } else if (intarg > 0) {
550 info->thread_pool_size = intarg;
551 } else {
552 ret = -EINVAL;
553 goto out;
554 }
555 break;
556 case Opt_max_inline:
557 num = match_strdup(&args[0]);
558 if (num) {
559 info->max_inline = memparse(num, NULL);
560 kfree(num);
561
562 if (info->max_inline) {
563 info->max_inline = min_t(u64,
564 info->max_inline,
565 root->sectorsize);
566 }
567 btrfs_info(root->fs_info, "max_inline at %llu",
568 info->max_inline);
569 } else {
570 ret = -ENOMEM;
571 goto out;
572 }
573 break;
574 case Opt_alloc_start:
575 num = match_strdup(&args[0]);
576 if (num) {
577 mutex_lock(&info->chunk_mutex);
578 info->alloc_start = memparse(num, NULL);
579 mutex_unlock(&info->chunk_mutex);
580 kfree(num);
581 btrfs_info(root->fs_info, "allocations start at %llu",
582 info->alloc_start);
583 } else {
584 ret = -ENOMEM;
585 goto out;
586 }
587 break;
588 case Opt_acl:
589 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
590 root->fs_info->sb->s_flags |= MS_POSIXACL;
591 break;
592 #else
593 btrfs_err(root->fs_info,
594 "support for ACL not compiled in!");
595 ret = -EINVAL;
596 goto out;
597 #endif
598 case Opt_noacl:
599 root->fs_info->sb->s_flags &= ~MS_POSIXACL;
600 break;
601 case Opt_notreelog:
602 btrfs_set_and_info(root, NOTREELOG,
603 "disabling tree log");
604 break;
605 case Opt_treelog:
606 btrfs_clear_and_info(root, NOTREELOG,
607 "enabling tree log");
608 break;
609 case Opt_flushoncommit:
610 btrfs_set_and_info(root, FLUSHONCOMMIT,
611 "turning on flush-on-commit");
612 break;
613 case Opt_noflushoncommit:
614 btrfs_clear_and_info(root, FLUSHONCOMMIT,
615 "turning off flush-on-commit");
616 break;
617 case Opt_ratio:
618 ret = match_int(&args[0], &intarg);
619 if (ret) {
620 goto out;
621 } else if (intarg >= 0) {
622 info->metadata_ratio = intarg;
623 btrfs_info(root->fs_info, "metadata ratio %d",
624 info->metadata_ratio);
625 } else {
626 ret = -EINVAL;
627 goto out;
628 }
629 break;
630 case Opt_discard:
631 btrfs_set_and_info(root, DISCARD,
632 "turning on discard");
633 break;
634 case Opt_nodiscard:
635 btrfs_clear_and_info(root, DISCARD,
636 "turning off discard");
637 break;
638 case Opt_space_cache:
639 case Opt_space_cache_version:
640 if (token == Opt_space_cache ||
641 strcmp(args[0].from, "v1") == 0) {
642 btrfs_clear_opt(root->fs_info->mount_opt,
643 FREE_SPACE_TREE);
644 btrfs_set_and_info(root, SPACE_CACHE,
645 "enabling disk space caching");
646 } else if (strcmp(args[0].from, "v2") == 0) {
647 btrfs_clear_opt(root->fs_info->mount_opt,
648 SPACE_CACHE);
649 btrfs_set_and_info(root, FREE_SPACE_TREE,
650 "enabling free space tree");
651 } else {
652 ret = -EINVAL;
653 goto out;
654 }
655 break;
656 case Opt_rescan_uuid_tree:
657 btrfs_set_opt(info->mount_opt, RESCAN_UUID_TREE);
658 break;
659 case Opt_no_space_cache:
660 if (btrfs_test_opt(root, SPACE_CACHE)) {
661 btrfs_clear_and_info(root, SPACE_CACHE,
662 "disabling disk space caching");
663 }
664 if (btrfs_test_opt(root, FREE_SPACE_TREE)) {
665 btrfs_clear_and_info(root, FREE_SPACE_TREE,
666 "disabling free space tree");
667 }
668 break;
669 case Opt_inode_cache:
670 btrfs_set_pending_and_info(info, INODE_MAP_CACHE,
671 "enabling inode map caching");
672 break;
673 case Opt_noinode_cache:
674 btrfs_clear_pending_and_info(info, INODE_MAP_CACHE,
675 "disabling inode map caching");
676 break;
677 case Opt_clear_cache:
678 btrfs_set_and_info(root, CLEAR_CACHE,
679 "force clearing of disk cache");
680 break;
681 case Opt_user_subvol_rm_allowed:
682 btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
683 break;
684 case Opt_enospc_debug:
685 btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
686 break;
687 case Opt_noenospc_debug:
688 btrfs_clear_opt(info->mount_opt, ENOSPC_DEBUG);
689 break;
690 case Opt_defrag:
691 btrfs_set_and_info(root, AUTO_DEFRAG,
692 "enabling auto defrag");
693 break;
694 case Opt_nodefrag:
695 btrfs_clear_and_info(root, AUTO_DEFRAG,
696 "disabling auto defrag");
697 break;
698 case Opt_recovery:
699 btrfs_info(root->fs_info, "enabling auto recovery");
700 btrfs_set_opt(info->mount_opt, RECOVERY);
701 break;
702 case Opt_skip_balance:
703 btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
704 break;
705 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
706 case Opt_check_integrity_including_extent_data:
707 btrfs_info(root->fs_info,
708 "enabling check integrity including extent data");
709 btrfs_set_opt(info->mount_opt,
710 CHECK_INTEGRITY_INCLUDING_EXTENT_DATA);
711 btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
712 break;
713 case Opt_check_integrity:
714 btrfs_info(root->fs_info, "enabling check integrity");
715 btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
716 break;
717 case Opt_check_integrity_print_mask:
718 ret = match_int(&args[0], &intarg);
719 if (ret) {
720 goto out;
721 } else if (intarg >= 0) {
722 info->check_integrity_print_mask = intarg;
723 btrfs_info(root->fs_info, "check_integrity_print_mask 0x%x",
724 info->check_integrity_print_mask);
725 } else {
726 ret = -EINVAL;
727 goto out;
728 }
729 break;
730 #else
731 case Opt_check_integrity_including_extent_data:
732 case Opt_check_integrity:
733 case Opt_check_integrity_print_mask:
734 btrfs_err(root->fs_info,
735 "support for check_integrity* not compiled in!");
736 ret = -EINVAL;
737 goto out;
738 #endif
739 case Opt_fatal_errors:
740 if (strcmp(args[0].from, "panic") == 0)
741 btrfs_set_opt(info->mount_opt,
742 PANIC_ON_FATAL_ERROR);
743 else if (strcmp(args[0].from, "bug") == 0)
744 btrfs_clear_opt(info->mount_opt,
745 PANIC_ON_FATAL_ERROR);
746 else {
747 ret = -EINVAL;
748 goto out;
749 }
750 break;
751 case Opt_commit_interval:
752 intarg = 0;
753 ret = match_int(&args[0], &intarg);
754 if (ret < 0) {
755 btrfs_err(root->fs_info, "invalid commit interval");
756 ret = -EINVAL;
757 goto out;
758 }
759 if (intarg > 0) {
760 if (intarg > 300) {
761 btrfs_warn(root->fs_info, "excessive commit interval %d",
762 intarg);
763 }
764 info->commit_interval = intarg;
765 } else {
766 btrfs_info(root->fs_info, "using default commit interval %ds",
767 BTRFS_DEFAULT_COMMIT_INTERVAL);
768 info->commit_interval = BTRFS_DEFAULT_COMMIT_INTERVAL;
769 }
770 break;
771 #ifdef CONFIG_BTRFS_DEBUG
772 case Opt_fragment_all:
773 btrfs_info(root->fs_info, "fragmenting all space");
774 btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
775 btrfs_set_opt(info->mount_opt, FRAGMENT_METADATA);
776 break;
777 case Opt_fragment_metadata:
778 btrfs_info(root->fs_info, "fragmenting metadata");
779 btrfs_set_opt(info->mount_opt,
780 FRAGMENT_METADATA);
781 break;
782 case Opt_fragment_data:
783 btrfs_info(root->fs_info, "fragmenting data");
784 btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
785 break;
786 #endif
787 case Opt_err:
788 btrfs_info(root->fs_info, "unrecognized mount option '%s'", p);
789 ret = -EINVAL;
790 goto out;
791 default:
792 break;
793 }
794 }
795 out:
796 if (btrfs_fs_compat_ro(root->fs_info, FREE_SPACE_TREE) &&
797 !btrfs_test_opt(root, FREE_SPACE_TREE) &&
798 !btrfs_test_opt(root, CLEAR_CACHE)) {
799 btrfs_err(root->fs_info, "cannot disable free space tree");
800 ret = -EINVAL;
801
802 }
803 if (!ret && btrfs_test_opt(root, SPACE_CACHE))
804 btrfs_info(root->fs_info, "disk space caching is enabled");
805 if (!ret && btrfs_test_opt(root, FREE_SPACE_TREE))
806 btrfs_info(root->fs_info, "using free space tree");
807 kfree(orig);
808 return ret;
809 }
810
811 /*
812 * Parse mount options that are required early in the mount process.
813 *
814 * All other options will be parsed on much later in the mount process and
815 * only when we need to allocate a new super block.
816 */
817 static int btrfs_parse_early_options(const char *options, fmode_t flags,
818 void *holder, char **subvol_name, u64 *subvol_objectid,
819 struct btrfs_fs_devices **fs_devices)
820 {
821 substring_t args[MAX_OPT_ARGS];
822 char *device_name, *opts, *orig, *p;
823 char *num = NULL;
824 int error = 0;
825
826 if (!options)
827 return 0;
828
829 /*
830 * strsep changes the string, duplicate it because parse_options
831 * gets called twice
832 */
833 opts = kstrdup(options, GFP_KERNEL);
834 if (!opts)
835 return -ENOMEM;
836 orig = opts;
837
838 while ((p = strsep(&opts, ",")) != NULL) {
839 int token;
840 if (!*p)
841 continue;
842
843 token = match_token(p, tokens, args);
844 switch (token) {
845 case Opt_subvol:
846 kfree(*subvol_name);
847 *subvol_name = match_strdup(&args[0]);
848 if (!*subvol_name) {
849 error = -ENOMEM;
850 goto out;
851 }
852 break;
853 case Opt_subvolid:
854 num = match_strdup(&args[0]);
855 if (num) {
856 *subvol_objectid = memparse(num, NULL);
857 kfree(num);
858 /* we want the original fs_tree */
859 if (!*subvol_objectid)
860 *subvol_objectid =
861 BTRFS_FS_TREE_OBJECTID;
862 } else {
863 error = -EINVAL;
864 goto out;
865 }
866 break;
867 case Opt_subvolrootid:
868 printk(KERN_WARNING
869 "BTRFS: 'subvolrootid' mount option is deprecated and has "
870 "no effect\n");
871 break;
872 case Opt_device:
873 device_name = match_strdup(&args[0]);
874 if (!device_name) {
875 error = -ENOMEM;
876 goto out;
877 }
878 error = btrfs_scan_one_device(device_name,
879 flags, holder, fs_devices);
880 kfree(device_name);
881 if (error)
882 goto out;
883 break;
884 default:
885 break;
886 }
887 }
888
889 out:
890 kfree(orig);
891 return error;
892 }
893
894 static char *get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
895 u64 subvol_objectid)
896 {
897 struct btrfs_root *root = fs_info->tree_root;
898 struct btrfs_root *fs_root;
899 struct btrfs_root_ref *root_ref;
900 struct btrfs_inode_ref *inode_ref;
901 struct btrfs_key key;
902 struct btrfs_path *path = NULL;
903 char *name = NULL, *ptr;
904 u64 dirid;
905 int len;
906 int ret;
907
908 path = btrfs_alloc_path();
909 if (!path) {
910 ret = -ENOMEM;
911 goto err;
912 }
913 path->leave_spinning = 1;
914
915 name = kmalloc(PATH_MAX, GFP_NOFS);
916 if (!name) {
917 ret = -ENOMEM;
918 goto err;
919 }
920 ptr = name + PATH_MAX - 1;
921 ptr[0] = '\0';
922
923 /*
924 * Walk up the subvolume trees in the tree of tree roots by root
925 * backrefs until we hit the top-level subvolume.
926 */
927 while (subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
928 key.objectid = subvol_objectid;
929 key.type = BTRFS_ROOT_BACKREF_KEY;
930 key.offset = (u64)-1;
931
932 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
933 if (ret < 0) {
934 goto err;
935 } else if (ret > 0) {
936 ret = btrfs_previous_item(root, path, subvol_objectid,
937 BTRFS_ROOT_BACKREF_KEY);
938 if (ret < 0) {
939 goto err;
940 } else if (ret > 0) {
941 ret = -ENOENT;
942 goto err;
943 }
944 }
945
946 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
947 subvol_objectid = key.offset;
948
949 root_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
950 struct btrfs_root_ref);
951 len = btrfs_root_ref_name_len(path->nodes[0], root_ref);
952 ptr -= len + 1;
953 if (ptr < name) {
954 ret = -ENAMETOOLONG;
955 goto err;
956 }
957 read_extent_buffer(path->nodes[0], ptr + 1,
958 (unsigned long)(root_ref + 1), len);
959 ptr[0] = '/';
960 dirid = btrfs_root_ref_dirid(path->nodes[0], root_ref);
961 btrfs_release_path(path);
962
963 key.objectid = subvol_objectid;
964 key.type = BTRFS_ROOT_ITEM_KEY;
965 key.offset = (u64)-1;
966 fs_root = btrfs_read_fs_root_no_name(fs_info, &key);
967 if (IS_ERR(fs_root)) {
968 ret = PTR_ERR(fs_root);
969 goto err;
970 }
971
972 /*
973 * Walk up the filesystem tree by inode refs until we hit the
974 * root directory.
975 */
976 while (dirid != BTRFS_FIRST_FREE_OBJECTID) {
977 key.objectid = dirid;
978 key.type = BTRFS_INODE_REF_KEY;
979 key.offset = (u64)-1;
980
981 ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0);
982 if (ret < 0) {
983 goto err;
984 } else if (ret > 0) {
985 ret = btrfs_previous_item(fs_root, path, dirid,
986 BTRFS_INODE_REF_KEY);
987 if (ret < 0) {
988 goto err;
989 } else if (ret > 0) {
990 ret = -ENOENT;
991 goto err;
992 }
993 }
994
995 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
996 dirid = key.offset;
997
998 inode_ref = btrfs_item_ptr(path->nodes[0],
999 path->slots[0],
1000 struct btrfs_inode_ref);
1001 len = btrfs_inode_ref_name_len(path->nodes[0],
1002 inode_ref);
1003 ptr -= len + 1;
1004 if (ptr < name) {
1005 ret = -ENAMETOOLONG;
1006 goto err;
1007 }
1008 read_extent_buffer(path->nodes[0], ptr + 1,
1009 (unsigned long)(inode_ref + 1), len);
1010 ptr[0] = '/';
1011 btrfs_release_path(path);
1012 }
1013 }
1014
1015 btrfs_free_path(path);
1016 if (ptr == name + PATH_MAX - 1) {
1017 name[0] = '/';
1018 name[1] = '\0';
1019 } else {
1020 memmove(name, ptr, name + PATH_MAX - ptr);
1021 }
1022 return name;
1023
1024 err:
1025 btrfs_free_path(path);
1026 kfree(name);
1027 return ERR_PTR(ret);
1028 }
1029
1030 static int get_default_subvol_objectid(struct btrfs_fs_info *fs_info, u64 *objectid)
1031 {
1032 struct btrfs_root *root = fs_info->tree_root;
1033 struct btrfs_dir_item *di;
1034 struct btrfs_path *path;
1035 struct btrfs_key location;
1036 u64 dir_id;
1037
1038 path = btrfs_alloc_path();
1039 if (!path)
1040 return -ENOMEM;
1041 path->leave_spinning = 1;
1042
1043 /*
1044 * Find the "default" dir item which points to the root item that we
1045 * will mount by default if we haven't been given a specific subvolume
1046 * to mount.
1047 */
1048 dir_id = btrfs_super_root_dir(fs_info->super_copy);
1049 di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
1050 if (IS_ERR(di)) {
1051 btrfs_free_path(path);
1052 return PTR_ERR(di);
1053 }
1054 if (!di) {
1055 /*
1056 * Ok the default dir item isn't there. This is weird since
1057 * it's always been there, but don't freak out, just try and
1058 * mount the top-level subvolume.
1059 */
1060 btrfs_free_path(path);
1061 *objectid = BTRFS_FS_TREE_OBJECTID;
1062 return 0;
1063 }
1064
1065 btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
1066 btrfs_free_path(path);
1067 *objectid = location.objectid;
1068 return 0;
1069 }
1070
1071 static int btrfs_fill_super(struct super_block *sb,
1072 struct btrfs_fs_devices *fs_devices,
1073 void *data, int silent)
1074 {
1075 struct inode *inode;
1076 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1077 struct btrfs_key key;
1078 int err;
1079
1080 sb->s_maxbytes = MAX_LFS_FILESIZE;
1081 sb->s_magic = BTRFS_SUPER_MAGIC;
1082 sb->s_op = &btrfs_super_ops;
1083 sb->s_d_op = &btrfs_dentry_operations;
1084 sb->s_export_op = &btrfs_export_ops;
1085 sb->s_xattr = btrfs_xattr_handlers;
1086 sb->s_time_gran = 1;
1087 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
1088 sb->s_flags |= MS_POSIXACL;
1089 #endif
1090 sb->s_flags |= MS_I_VERSION;
1091 sb->s_iflags |= SB_I_CGROUPWB;
1092 err = open_ctree(sb, fs_devices, (char *)data);
1093 if (err) {
1094 printk(KERN_ERR "BTRFS: open_ctree failed\n");
1095 return err;
1096 }
1097
1098 key.objectid = BTRFS_FIRST_FREE_OBJECTID;
1099 key.type = BTRFS_INODE_ITEM_KEY;
1100 key.offset = 0;
1101 inode = btrfs_iget(sb, &key, fs_info->fs_root, NULL);
1102 if (IS_ERR(inode)) {
1103 err = PTR_ERR(inode);
1104 goto fail_close;
1105 }
1106
1107 sb->s_root = d_make_root(inode);
1108 if (!sb->s_root) {
1109 err = -ENOMEM;
1110 goto fail_close;
1111 }
1112
1113 save_mount_options(sb, data);
1114 cleancache_init_fs(sb);
1115 sb->s_flags |= MS_ACTIVE;
1116 return 0;
1117
1118 fail_close:
1119 close_ctree(fs_info->tree_root);
1120 return err;
1121 }
1122
1123 int btrfs_sync_fs(struct super_block *sb, int wait)
1124 {
1125 struct btrfs_trans_handle *trans;
1126 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1127 struct btrfs_root *root = fs_info->tree_root;
1128
1129 trace_btrfs_sync_fs(wait);
1130
1131 if (!wait) {
1132 filemap_flush(fs_info->btree_inode->i_mapping);
1133 return 0;
1134 }
1135
1136 btrfs_wait_ordered_roots(fs_info, -1);
1137
1138 trans = btrfs_attach_transaction_barrier(root);
1139 if (IS_ERR(trans)) {
1140 /* no transaction, don't bother */
1141 if (PTR_ERR(trans) == -ENOENT) {
1142 /*
1143 * Exit unless we have some pending changes
1144 * that need to go through commit
1145 */
1146 if (fs_info->pending_changes == 0)
1147 return 0;
1148 /*
1149 * A non-blocking test if the fs is frozen. We must not
1150 * start a new transaction here otherwise a deadlock
1151 * happens. The pending operations are delayed to the
1152 * next commit after thawing.
1153 */
1154 if (__sb_start_write(sb, SB_FREEZE_WRITE, false))
1155 __sb_end_write(sb, SB_FREEZE_WRITE);
1156 else
1157 return 0;
1158 trans = btrfs_start_transaction(root, 0);
1159 }
1160 if (IS_ERR(trans))
1161 return PTR_ERR(trans);
1162 }
1163 return btrfs_commit_transaction(trans, root);
1164 }
1165
1166 static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
1167 {
1168 struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
1169 struct btrfs_root *root = info->tree_root;
1170 char *compress_type;
1171
1172 if (btrfs_test_opt(root, DEGRADED))
1173 seq_puts(seq, ",degraded");
1174 if (btrfs_test_opt(root, NODATASUM))
1175 seq_puts(seq, ",nodatasum");
1176 if (btrfs_test_opt(root, NODATACOW))
1177 seq_puts(seq, ",nodatacow");
1178 if (btrfs_test_opt(root, NOBARRIER))
1179 seq_puts(seq, ",nobarrier");
1180 if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE)
1181 seq_printf(seq, ",max_inline=%llu", info->max_inline);
1182 if (info->alloc_start != 0)
1183 seq_printf(seq, ",alloc_start=%llu", info->alloc_start);
1184 if (info->thread_pool_size != min_t(unsigned long,
1185 num_online_cpus() + 2, 8))
1186 seq_printf(seq, ",thread_pool=%d", info->thread_pool_size);
1187 if (btrfs_test_opt(root, COMPRESS)) {
1188 if (info->compress_type == BTRFS_COMPRESS_ZLIB)
1189 compress_type = "zlib";
1190 else
1191 compress_type = "lzo";
1192 if (btrfs_test_opt(root, FORCE_COMPRESS))
1193 seq_printf(seq, ",compress-force=%s", compress_type);
1194 else
1195 seq_printf(seq, ",compress=%s", compress_type);
1196 }
1197 if (btrfs_test_opt(root, NOSSD))
1198 seq_puts(seq, ",nossd");
1199 if (btrfs_test_opt(root, SSD_SPREAD))
1200 seq_puts(seq, ",ssd_spread");
1201 else if (btrfs_test_opt(root, SSD))
1202 seq_puts(seq, ",ssd");
1203 if (btrfs_test_opt(root, NOTREELOG))
1204 seq_puts(seq, ",notreelog");
1205 if (btrfs_test_opt(root, FLUSHONCOMMIT))
1206 seq_puts(seq, ",flushoncommit");
1207 if (btrfs_test_opt(root, DISCARD))
1208 seq_puts(seq, ",discard");
1209 if (!(root->fs_info->sb->s_flags & MS_POSIXACL))
1210 seq_puts(seq, ",noacl");
1211 if (btrfs_test_opt(root, SPACE_CACHE))
1212 seq_puts(seq, ",space_cache");
1213 else if (btrfs_test_opt(root, FREE_SPACE_TREE))
1214 seq_puts(seq, ",space_cache=v2");
1215 else
1216 seq_puts(seq, ",nospace_cache");
1217 if (btrfs_test_opt(root, RESCAN_UUID_TREE))
1218 seq_puts(seq, ",rescan_uuid_tree");
1219 if (btrfs_test_opt(root, CLEAR_CACHE))
1220 seq_puts(seq, ",clear_cache");
1221 if (btrfs_test_opt(root, USER_SUBVOL_RM_ALLOWED))
1222 seq_puts(seq, ",user_subvol_rm_allowed");
1223 if (btrfs_test_opt(root, ENOSPC_DEBUG))
1224 seq_puts(seq, ",enospc_debug");
1225 if (btrfs_test_opt(root, AUTO_DEFRAG))
1226 seq_puts(seq, ",autodefrag");
1227 if (btrfs_test_opt(root, INODE_MAP_CACHE))
1228 seq_puts(seq, ",inode_cache");
1229 if (btrfs_test_opt(root, SKIP_BALANCE))
1230 seq_puts(seq, ",skip_balance");
1231 if (btrfs_test_opt(root, RECOVERY))
1232 seq_puts(seq, ",recovery");
1233 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
1234 if (btrfs_test_opt(root, CHECK_INTEGRITY_INCLUDING_EXTENT_DATA))
1235 seq_puts(seq, ",check_int_data");
1236 else if (btrfs_test_opt(root, CHECK_INTEGRITY))
1237 seq_puts(seq, ",check_int");
1238 if (info->check_integrity_print_mask)
1239 seq_printf(seq, ",check_int_print_mask=%d",
1240 info->check_integrity_print_mask);
1241 #endif
1242 if (info->metadata_ratio)
1243 seq_printf(seq, ",metadata_ratio=%d",
1244 info->metadata_ratio);
1245 if (btrfs_test_opt(root, PANIC_ON_FATAL_ERROR))
1246 seq_puts(seq, ",fatal_errors=panic");
1247 if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL)
1248 seq_printf(seq, ",commit=%d", info->commit_interval);
1249 #ifdef CONFIG_BTRFS_DEBUG
1250 if (btrfs_test_opt(root, FRAGMENT_DATA))
1251 seq_puts(seq, ",fragment=data");
1252 if (btrfs_test_opt(root, FRAGMENT_METADATA))
1253 seq_puts(seq, ",fragment=metadata");
1254 #endif
1255 seq_printf(seq, ",subvolid=%llu",
1256 BTRFS_I(d_inode(dentry))->root->root_key.objectid);
1257 seq_puts(seq, ",subvol=");
1258 seq_dentry(seq, dentry, " \t\n\\");
1259 return 0;
1260 }
1261
1262 static int btrfs_test_super(struct super_block *s, void *data)
1263 {
1264 struct btrfs_fs_info *p = data;
1265 struct btrfs_fs_info *fs_info = btrfs_sb(s);
1266
1267 return fs_info->fs_devices == p->fs_devices;
1268 }
1269
1270 static int btrfs_set_super(struct super_block *s, void *data)
1271 {
1272 int err = set_anon_super(s, data);
1273 if (!err)
1274 s->s_fs_info = data;
1275 return err;
1276 }
1277
1278 /*
1279 * subvolumes are identified by ino 256
1280 */
1281 static inline int is_subvolume_inode(struct inode *inode)
1282 {
1283 if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
1284 return 1;
1285 return 0;
1286 }
1287
1288 /*
1289 * This will add subvolid=0 to the argument string while removing any subvol=
1290 * and subvolid= arguments to make sure we get the top-level root for path
1291 * walking to the subvol we want.
1292 */
1293 static char *setup_root_args(char *args)
1294 {
1295 char *buf, *dst, *sep;
1296
1297 if (!args)
1298 return kstrdup("subvolid=0", GFP_NOFS);
1299
1300 /* The worst case is that we add ",subvolid=0" to the end. */
1301 buf = dst = kmalloc(strlen(args) + strlen(",subvolid=0") + 1, GFP_NOFS);
1302 if (!buf)
1303 return NULL;
1304
1305 while (1) {
1306 sep = strchrnul(args, ',');
1307 if (!strstarts(args, "subvol=") &&
1308 !strstarts(args, "subvolid=")) {
1309 memcpy(dst, args, sep - args);
1310 dst += sep - args;
1311 *dst++ = ',';
1312 }
1313 if (*sep)
1314 args = sep + 1;
1315 else
1316 break;
1317 }
1318 strcpy(dst, "subvolid=0");
1319
1320 return buf;
1321 }
1322
1323 static struct dentry *mount_subvol(const char *subvol_name, u64 subvol_objectid,
1324 int flags, const char *device_name,
1325 char *data)
1326 {
1327 struct dentry *root;
1328 struct vfsmount *mnt = NULL;
1329 char *newargs;
1330 int ret;
1331
1332 newargs = setup_root_args(data);
1333 if (!newargs) {
1334 root = ERR_PTR(-ENOMEM);
1335 goto out;
1336 }
1337
1338 mnt = vfs_kern_mount(&btrfs_fs_type, flags, device_name, newargs);
1339 if (PTR_ERR_OR_ZERO(mnt) == -EBUSY) {
1340 if (flags & MS_RDONLY) {
1341 mnt = vfs_kern_mount(&btrfs_fs_type, flags & ~MS_RDONLY,
1342 device_name, newargs);
1343 } else {
1344 mnt = vfs_kern_mount(&btrfs_fs_type, flags | MS_RDONLY,
1345 device_name, newargs);
1346 if (IS_ERR(mnt)) {
1347 root = ERR_CAST(mnt);
1348 mnt = NULL;
1349 goto out;
1350 }
1351
1352 down_write(&mnt->mnt_sb->s_umount);
1353 ret = btrfs_remount(mnt->mnt_sb, &flags, NULL);
1354 up_write(&mnt->mnt_sb->s_umount);
1355 if (ret < 0) {
1356 root = ERR_PTR(ret);
1357 goto out;
1358 }
1359 }
1360 }
1361 if (IS_ERR(mnt)) {
1362 root = ERR_CAST(mnt);
1363 mnt = NULL;
1364 goto out;
1365 }
1366
1367 if (!subvol_name) {
1368 if (!subvol_objectid) {
1369 ret = get_default_subvol_objectid(btrfs_sb(mnt->mnt_sb),
1370 &subvol_objectid);
1371 if (ret) {
1372 root = ERR_PTR(ret);
1373 goto out;
1374 }
1375 }
1376 subvol_name = get_subvol_name_from_objectid(btrfs_sb(mnt->mnt_sb),
1377 subvol_objectid);
1378 if (IS_ERR(subvol_name)) {
1379 root = ERR_CAST(subvol_name);
1380 subvol_name = NULL;
1381 goto out;
1382 }
1383
1384 }
1385
1386 root = mount_subtree(mnt, subvol_name);
1387 /* mount_subtree() drops our reference on the vfsmount. */
1388 mnt = NULL;
1389
1390 if (!IS_ERR(root)) {
1391 struct super_block *s = root->d_sb;
1392 struct inode *root_inode = d_inode(root);
1393 u64 root_objectid = BTRFS_I(root_inode)->root->root_key.objectid;
1394
1395 ret = 0;
1396 if (!is_subvolume_inode(root_inode)) {
1397 pr_err("BTRFS: '%s' is not a valid subvolume\n",
1398 subvol_name);
1399 ret = -EINVAL;
1400 }
1401 if (subvol_objectid && root_objectid != subvol_objectid) {
1402 /*
1403 * This will also catch a race condition where a
1404 * subvolume which was passed by ID is renamed and
1405 * another subvolume is renamed over the old location.
1406 */
1407 pr_err("BTRFS: subvol '%s' does not match subvolid %llu\n",
1408 subvol_name, subvol_objectid);
1409 ret = -EINVAL;
1410 }
1411 if (ret) {
1412 dput(root);
1413 root = ERR_PTR(ret);
1414 deactivate_locked_super(s);
1415 }
1416 }
1417
1418 out:
1419 mntput(mnt);
1420 kfree(newargs);
1421 kfree(subvol_name);
1422 return root;
1423 }
1424
1425 static int parse_security_options(char *orig_opts,
1426 struct security_mnt_opts *sec_opts)
1427 {
1428 char *secdata = NULL;
1429 int ret = 0;
1430
1431 secdata = alloc_secdata();
1432 if (!secdata)
1433 return -ENOMEM;
1434 ret = security_sb_copy_data(orig_opts, secdata);
1435 if (ret) {
1436 free_secdata(secdata);
1437 return ret;
1438 }
1439 ret = security_sb_parse_opts_str(secdata, sec_opts);
1440 free_secdata(secdata);
1441 return ret;
1442 }
1443
1444 static int setup_security_options(struct btrfs_fs_info *fs_info,
1445 struct super_block *sb,
1446 struct security_mnt_opts *sec_opts)
1447 {
1448 int ret = 0;
1449
1450 /*
1451 * Call security_sb_set_mnt_opts() to check whether new sec_opts
1452 * is valid.
1453 */
1454 ret = security_sb_set_mnt_opts(sb, sec_opts, 0, NULL);
1455 if (ret)
1456 return ret;
1457
1458 #ifdef CONFIG_SECURITY
1459 if (!fs_info->security_opts.num_mnt_opts) {
1460 /* first time security setup, copy sec_opts to fs_info */
1461 memcpy(&fs_info->security_opts, sec_opts, sizeof(*sec_opts));
1462 } else {
1463 /*
1464 * Since SELinux(the only one supports security_mnt_opts) does
1465 * NOT support changing context during remount/mount same sb,
1466 * This must be the same or part of the same security options,
1467 * just free it.
1468 */
1469 security_free_mnt_opts(sec_opts);
1470 }
1471 #endif
1472 return ret;
1473 }
1474
1475 /*
1476 * Find a superblock for the given device / mount point.
1477 *
1478 * Note: This is based on get_sb_bdev from fs/super.c with a few additions
1479 * for multiple device setup. Make sure to keep it in sync.
1480 */
1481 static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
1482 const char *device_name, void *data)
1483 {
1484 struct block_device *bdev = NULL;
1485 struct super_block *s;
1486 struct btrfs_fs_devices *fs_devices = NULL;
1487 struct btrfs_fs_info *fs_info = NULL;
1488 struct security_mnt_opts new_sec_opts;
1489 fmode_t mode = FMODE_READ;
1490 char *subvol_name = NULL;
1491 u64 subvol_objectid = 0;
1492 int error = 0;
1493
1494 if (!(flags & MS_RDONLY))
1495 mode |= FMODE_WRITE;
1496
1497 error = btrfs_parse_early_options(data, mode, fs_type,
1498 &subvol_name, &subvol_objectid,
1499 &fs_devices);
1500 if (error) {
1501 kfree(subvol_name);
1502 return ERR_PTR(error);
1503 }
1504
1505 if (subvol_name || subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
1506 /* mount_subvol() will free subvol_name. */
1507 return mount_subvol(subvol_name, subvol_objectid, flags,
1508 device_name, data);
1509 }
1510
1511 security_init_mnt_opts(&new_sec_opts);
1512 if (data) {
1513 error = parse_security_options(data, &new_sec_opts);
1514 if (error)
1515 return ERR_PTR(error);
1516 }
1517
1518 error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices);
1519 if (error)
1520 goto error_sec_opts;
1521
1522 /*
1523 * Setup a dummy root and fs_info for test/set super. This is because
1524 * we don't actually fill this stuff out until open_ctree, but we need
1525 * it for searching for existing supers, so this lets us do that and
1526 * then open_ctree will properly initialize everything later.
1527 */
1528 fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_NOFS);
1529 if (!fs_info) {
1530 error = -ENOMEM;
1531 goto error_sec_opts;
1532 }
1533
1534 fs_info->fs_devices = fs_devices;
1535
1536 fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
1537 fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
1538 security_init_mnt_opts(&fs_info->security_opts);
1539 if (!fs_info->super_copy || !fs_info->super_for_commit) {
1540 error = -ENOMEM;
1541 goto error_fs_info;
1542 }
1543
1544 error = btrfs_open_devices(fs_devices, mode, fs_type);
1545 if (error)
1546 goto error_fs_info;
1547
1548 if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
1549 error = -EACCES;
1550 goto error_close_devices;
1551 }
1552
1553 bdev = fs_devices->latest_bdev;
1554 s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | MS_NOSEC,
1555 fs_info);
1556 if (IS_ERR(s)) {
1557 error = PTR_ERR(s);
1558 goto error_close_devices;
1559 }
1560
1561 if (s->s_root) {
1562 btrfs_close_devices(fs_devices);
1563 free_fs_info(fs_info);
1564 if ((flags ^ s->s_flags) & MS_RDONLY)
1565 error = -EBUSY;
1566 } else {
1567 snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev);
1568 btrfs_sb(s)->bdev_holder = fs_type;
1569 error = btrfs_fill_super(s, fs_devices, data,
1570 flags & MS_SILENT ? 1 : 0);
1571 }
1572 if (error) {
1573 deactivate_locked_super(s);
1574 goto error_sec_opts;
1575 }
1576
1577 fs_info = btrfs_sb(s);
1578 error = setup_security_options(fs_info, s, &new_sec_opts);
1579 if (error) {
1580 deactivate_locked_super(s);
1581 goto error_sec_opts;
1582 }
1583
1584 return dget(s->s_root);
1585
1586 error_close_devices:
1587 btrfs_close_devices(fs_devices);
1588 error_fs_info:
1589 free_fs_info(fs_info);
1590 error_sec_opts:
1591 security_free_mnt_opts(&new_sec_opts);
1592 return ERR_PTR(error);
1593 }
1594
1595 static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
1596 int new_pool_size, int old_pool_size)
1597 {
1598 if (new_pool_size == old_pool_size)
1599 return;
1600
1601 fs_info->thread_pool_size = new_pool_size;
1602
1603 btrfs_info(fs_info, "resize thread pool %d -> %d",
1604 old_pool_size, new_pool_size);
1605
1606 btrfs_workqueue_set_max(fs_info->workers, new_pool_size);
1607 btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size);
1608 btrfs_workqueue_set_max(fs_info->submit_workers, new_pool_size);
1609 btrfs_workqueue_set_max(fs_info->caching_workers, new_pool_size);
1610 btrfs_workqueue_set_max(fs_info->endio_workers, new_pool_size);
1611 btrfs_workqueue_set_max(fs_info->endio_meta_workers, new_pool_size);
1612 btrfs_workqueue_set_max(fs_info->endio_meta_write_workers,
1613 new_pool_size);
1614 btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size);
1615 btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
1616 btrfs_workqueue_set_max(fs_info->delayed_workers, new_pool_size);
1617 btrfs_workqueue_set_max(fs_info->readahead_workers, new_pool_size);
1618 btrfs_workqueue_set_max(fs_info->scrub_wr_completion_workers,
1619 new_pool_size);
1620 }
1621
1622 static inline void btrfs_remount_prepare(struct btrfs_fs_info *fs_info)
1623 {
1624 set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1625 }
1626
1627 static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info,
1628 unsigned long old_opts, int flags)
1629 {
1630 if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1631 (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1632 (flags & MS_RDONLY))) {
1633 /* wait for any defraggers to finish */
1634 wait_event(fs_info->transaction_wait,
1635 (atomic_read(&fs_info->defrag_running) == 0));
1636 if (flags & MS_RDONLY)
1637 sync_filesystem(fs_info->sb);
1638 }
1639 }
1640
1641 static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
1642 unsigned long old_opts)
1643 {
1644 /*
1645 * We need cleanup all defragable inodes if the autodefragment is
1646 * close or the fs is R/O.
1647 */
1648 if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1649 (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1650 (fs_info->sb->s_flags & MS_RDONLY))) {
1651 btrfs_cleanup_defrag_inodes(fs_info);
1652 }
1653
1654 clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1655 }
1656
1657 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
1658 {
1659 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1660 struct btrfs_root *root = fs_info->tree_root;
1661 unsigned old_flags = sb->s_flags;
1662 unsigned long old_opts = fs_info->mount_opt;
1663 unsigned long old_compress_type = fs_info->compress_type;
1664 u64 old_max_inline = fs_info->max_inline;
1665 u64 old_alloc_start = fs_info->alloc_start;
1666 int old_thread_pool_size = fs_info->thread_pool_size;
1667 unsigned int old_metadata_ratio = fs_info->metadata_ratio;
1668 int ret;
1669
1670 sync_filesystem(sb);
1671 btrfs_remount_prepare(fs_info);
1672
1673 if (data) {
1674 struct security_mnt_opts new_sec_opts;
1675
1676 security_init_mnt_opts(&new_sec_opts);
1677 ret = parse_security_options(data, &new_sec_opts);
1678 if (ret)
1679 goto restore;
1680 ret = setup_security_options(fs_info, sb,
1681 &new_sec_opts);
1682 if (ret) {
1683 security_free_mnt_opts(&new_sec_opts);
1684 goto restore;
1685 }
1686 }
1687
1688 ret = btrfs_parse_options(root, data);
1689 if (ret) {
1690 ret = -EINVAL;
1691 goto restore;
1692 }
1693
1694 btrfs_remount_begin(fs_info, old_opts, *flags);
1695 btrfs_resize_thread_pool(fs_info,
1696 fs_info->thread_pool_size, old_thread_pool_size);
1697
1698 if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1699 goto out;
1700
1701 if (*flags & MS_RDONLY) {
1702 /*
1703 * this also happens on 'umount -rf' or on shutdown, when
1704 * the filesystem is busy.
1705 */
1706 cancel_work_sync(&fs_info->async_reclaim_work);
1707
1708 /* wait for the uuid_scan task to finish */
1709 down(&fs_info->uuid_tree_rescan_sem);
1710 /* avoid complains from lockdep et al. */
1711 up(&fs_info->uuid_tree_rescan_sem);
1712
1713 sb->s_flags |= MS_RDONLY;
1714
1715 /*
1716 * Setting MS_RDONLY will put the cleaner thread to
1717 * sleep at the next loop if it's already active.
1718 * If it's already asleep, we'll leave unused block
1719 * groups on disk until we're mounted read-write again
1720 * unless we clean them up here.
1721 */
1722 btrfs_delete_unused_bgs(fs_info);
1723
1724 btrfs_dev_replace_suspend_for_unmount(fs_info);
1725 btrfs_scrub_cancel(fs_info);
1726 btrfs_pause_balance(fs_info);
1727
1728 ret = btrfs_commit_super(root);
1729 if (ret)
1730 goto restore;
1731 } else {
1732 if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state)) {
1733 btrfs_err(fs_info,
1734 "Remounting read-write after error is not allowed");
1735 ret = -EINVAL;
1736 goto restore;
1737 }
1738 if (fs_info->fs_devices->rw_devices == 0) {
1739 ret = -EACCES;
1740 goto restore;
1741 }
1742
1743 if (fs_info->fs_devices->missing_devices >
1744 fs_info->num_tolerated_disk_barrier_failures &&
1745 !(*flags & MS_RDONLY)) {
1746 btrfs_warn(fs_info,
1747 "too many missing devices, writeable remount is not allowed");
1748 ret = -EACCES;
1749 goto restore;
1750 }
1751
1752 if (btrfs_super_log_root(fs_info->super_copy) != 0) {
1753 ret = -EINVAL;
1754 goto restore;
1755 }
1756
1757 ret = btrfs_cleanup_fs_roots(fs_info);
1758 if (ret)
1759 goto restore;
1760
1761 /* recover relocation */
1762 mutex_lock(&fs_info->cleaner_mutex);
1763 ret = btrfs_recover_relocation(root);
1764 mutex_unlock(&fs_info->cleaner_mutex);
1765 if (ret)
1766 goto restore;
1767
1768 ret = btrfs_resume_balance_async(fs_info);
1769 if (ret)
1770 goto restore;
1771
1772 ret = btrfs_resume_dev_replace_async(fs_info);
1773 if (ret) {
1774 btrfs_warn(fs_info, "failed to resume dev_replace");
1775 goto restore;
1776 }
1777
1778 if (!fs_info->uuid_root) {
1779 btrfs_info(fs_info, "creating UUID tree");
1780 ret = btrfs_create_uuid_tree(fs_info);
1781 if (ret) {
1782 btrfs_warn(fs_info, "failed to create the UUID tree %d", ret);
1783 goto restore;
1784 }
1785 }
1786 sb->s_flags &= ~MS_RDONLY;
1787 }
1788 out:
1789 wake_up_process(fs_info->transaction_kthread);
1790 btrfs_remount_cleanup(fs_info, old_opts);
1791 return 0;
1792
1793 restore:
1794 /* We've hit an error - don't reset MS_RDONLY */
1795 if (sb->s_flags & MS_RDONLY)
1796 old_flags |= MS_RDONLY;
1797 sb->s_flags = old_flags;
1798 fs_info->mount_opt = old_opts;
1799 fs_info->compress_type = old_compress_type;
1800 fs_info->max_inline = old_max_inline;
1801 mutex_lock(&fs_info->chunk_mutex);
1802 fs_info->alloc_start = old_alloc_start;
1803 mutex_unlock(&fs_info->chunk_mutex);
1804 btrfs_resize_thread_pool(fs_info,
1805 old_thread_pool_size, fs_info->thread_pool_size);
1806 fs_info->metadata_ratio = old_metadata_ratio;
1807 btrfs_remount_cleanup(fs_info, old_opts);
1808 return ret;
1809 }
1810
1811 /* Used to sort the devices by max_avail(descending sort) */
1812 static int btrfs_cmp_device_free_bytes(const void *dev_info1,
1813 const void *dev_info2)
1814 {
1815 if (((struct btrfs_device_info *)dev_info1)->max_avail >
1816 ((struct btrfs_device_info *)dev_info2)->max_avail)
1817 return -1;
1818 else if (((struct btrfs_device_info *)dev_info1)->max_avail <
1819 ((struct btrfs_device_info *)dev_info2)->max_avail)
1820 return 1;
1821 else
1822 return 0;
1823 }
1824
1825 /*
1826 * sort the devices by max_avail, in which max free extent size of each device
1827 * is stored.(Descending Sort)
1828 */
1829 static inline void btrfs_descending_sort_devices(
1830 struct btrfs_device_info *devices,
1831 size_t nr_devices)
1832 {
1833 sort(devices, nr_devices, sizeof(struct btrfs_device_info),
1834 btrfs_cmp_device_free_bytes, NULL);
1835 }
1836
1837 /*
1838 * The helper to calc the free space on the devices that can be used to store
1839 * file data.
1840 */
1841 static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes)
1842 {
1843 struct btrfs_fs_info *fs_info = root->fs_info;
1844 struct btrfs_device_info *devices_info;
1845 struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
1846 struct btrfs_device *device;
1847 u64 skip_space;
1848 u64 type;
1849 u64 avail_space;
1850 u64 used_space;
1851 u64 min_stripe_size;
1852 int min_stripes = 1, num_stripes = 1;
1853 int i = 0, nr_devices;
1854 int ret;
1855
1856 /*
1857 * We aren't under the device list lock, so this is racey-ish, but good
1858 * enough for our purposes.
1859 */
1860 nr_devices = fs_info->fs_devices->open_devices;
1861 if (!nr_devices) {
1862 smp_mb();
1863 nr_devices = fs_info->fs_devices->open_devices;
1864 ASSERT(nr_devices);
1865 if (!nr_devices) {
1866 *free_bytes = 0;
1867 return 0;
1868 }
1869 }
1870
1871 devices_info = kmalloc_array(nr_devices, sizeof(*devices_info),
1872 GFP_NOFS);
1873 if (!devices_info)
1874 return -ENOMEM;
1875
1876 /* calc min stripe number for data space alloction */
1877 type = btrfs_get_alloc_profile(root, 1);
1878 if (type & BTRFS_BLOCK_GROUP_RAID0) {
1879 min_stripes = 2;
1880 num_stripes = nr_devices;
1881 } else if (type & BTRFS_BLOCK_GROUP_RAID1) {
1882 min_stripes = 2;
1883 num_stripes = 2;
1884 } else if (type & BTRFS_BLOCK_GROUP_RAID10) {
1885 min_stripes = 4;
1886 num_stripes = 4;
1887 }
1888
1889 if (type & BTRFS_BLOCK_GROUP_DUP)
1890 min_stripe_size = 2 * BTRFS_STRIPE_LEN;
1891 else
1892 min_stripe_size = BTRFS_STRIPE_LEN;
1893
1894 if (fs_info->alloc_start)
1895 mutex_lock(&fs_devices->device_list_mutex);
1896 rcu_read_lock();
1897 list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
1898 if (!device->in_fs_metadata || !device->bdev ||
1899 device->is_tgtdev_for_dev_replace)
1900 continue;
1901
1902 if (i >= nr_devices)
1903 break;
1904
1905 avail_space = device->total_bytes - device->bytes_used;
1906
1907 /* align with stripe_len */
1908 avail_space = div_u64(avail_space, BTRFS_STRIPE_LEN);
1909 avail_space *= BTRFS_STRIPE_LEN;
1910
1911 /*
1912 * In order to avoid overwritting the superblock on the drive,
1913 * btrfs starts at an offset of at least 1MB when doing chunk
1914 * allocation.
1915 */
1916 skip_space = SZ_1M;
1917
1918 /* user can set the offset in fs_info->alloc_start. */
1919 if (fs_info->alloc_start &&
1920 fs_info->alloc_start + BTRFS_STRIPE_LEN <=
1921 device->total_bytes) {
1922 rcu_read_unlock();
1923 skip_space = max(fs_info->alloc_start, skip_space);
1924
1925 /*
1926 * btrfs can not use the free space in
1927 * [0, skip_space - 1], we must subtract it from the
1928 * total. In order to implement it, we account the used
1929 * space in this range first.
1930 */
1931 ret = btrfs_account_dev_extents_size(device, 0,
1932 skip_space - 1,
1933 &used_space);
1934 if (ret) {
1935 kfree(devices_info);
1936 mutex_unlock(&fs_devices->device_list_mutex);
1937 return ret;
1938 }
1939
1940 rcu_read_lock();
1941
1942 /* calc the free space in [0, skip_space - 1] */
1943 skip_space -= used_space;
1944 }
1945
1946 /*
1947 * we can use the free space in [0, skip_space - 1], subtract
1948 * it from the total.
1949 */
1950 if (avail_space && avail_space >= skip_space)
1951 avail_space -= skip_space;
1952 else
1953 avail_space = 0;
1954
1955 if (avail_space < min_stripe_size)
1956 continue;
1957
1958 devices_info[i].dev = device;
1959 devices_info[i].max_avail = avail_space;
1960
1961 i++;
1962 }
1963 rcu_read_unlock();
1964 if (fs_info->alloc_start)
1965 mutex_unlock(&fs_devices->device_list_mutex);
1966
1967 nr_devices = i;
1968
1969 btrfs_descending_sort_devices(devices_info, nr_devices);
1970
1971 i = nr_devices - 1;
1972 avail_space = 0;
1973 while (nr_devices >= min_stripes) {
1974 if (num_stripes > nr_devices)
1975 num_stripes = nr_devices;
1976
1977 if (devices_info[i].max_avail >= min_stripe_size) {
1978 int j;
1979 u64 alloc_size;
1980
1981 avail_space += devices_info[i].max_avail * num_stripes;
1982 alloc_size = devices_info[i].max_avail;
1983 for (j = i + 1 - num_stripes; j <= i; j++)
1984 devices_info[j].max_avail -= alloc_size;
1985 }
1986 i--;
1987 nr_devices--;
1988 }
1989
1990 kfree(devices_info);
1991 *free_bytes = avail_space;
1992 return 0;
1993 }
1994
1995 /*
1996 * Calculate numbers for 'df', pessimistic in case of mixed raid profiles.
1997 *
1998 * If there's a redundant raid level at DATA block groups, use the respective
1999 * multiplier to scale the sizes.
2000 *
2001 * Unused device space usage is based on simulating the chunk allocator
2002 * algorithm that respects the device sizes, order of allocations and the
2003 * 'alloc_start' value, this is a close approximation of the actual use but
2004 * there are other factors that may change the result (like a new metadata
2005 * chunk).
2006 *
2007 * If metadata is exhausted, f_bavail will be 0.
2008 *
2009 * FIXME: not accurate for mixed block groups, total and free/used are ok,
2010 * available appears slightly larger.
2011 */
2012 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
2013 {
2014 struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
2015 struct btrfs_super_block *disk_super = fs_info->super_copy;
2016 struct list_head *head = &fs_info->space_info;
2017 struct btrfs_space_info *found;
2018 u64 total_used = 0;
2019 u64 total_free_data = 0;
2020 u64 total_free_meta = 0;
2021 int bits = dentry->d_sb->s_blocksize_bits;
2022 __be32 *fsid = (__be32 *)fs_info->fsid;
2023 unsigned factor = 1;
2024 struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
2025 int ret;
2026 u64 thresh = 0;
2027
2028 /*
2029 * holding chunk_muext to avoid allocating new chunks, holding
2030 * device_list_mutex to avoid the device being removed
2031 */
2032 rcu_read_lock();
2033 list_for_each_entry_rcu(found, head, list) {
2034 if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
2035 int i;
2036
2037 total_free_data += found->disk_total - found->disk_used;
2038 total_free_data -=
2039 btrfs_account_ro_block_groups_free_space(found);
2040
2041 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
2042 if (!list_empty(&found->block_groups[i])) {
2043 switch (i) {
2044 case BTRFS_RAID_DUP:
2045 case BTRFS_RAID_RAID1:
2046 case BTRFS_RAID_RAID10:
2047 factor = 2;
2048 }
2049 }
2050 }
2051 }
2052 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
2053 total_free_meta += found->disk_total - found->disk_used;
2054
2055 total_used += found->disk_used;
2056 }
2057
2058 rcu_read_unlock();
2059
2060 buf->f_blocks = div_u64(btrfs_super_total_bytes(disk_super), factor);
2061 buf->f_blocks >>= bits;
2062 buf->f_bfree = buf->f_blocks - (div_u64(total_used, factor) >> bits);
2063
2064 /* Account global block reserve as used, it's in logical size already */
2065 spin_lock(&block_rsv->lock);
2066 buf->f_bfree -= block_rsv->size >> bits;
2067 spin_unlock(&block_rsv->lock);
2068
2069 buf->f_bavail = div_u64(total_free_data, factor);
2070 ret = btrfs_calc_avail_data_space(fs_info->tree_root, &total_free_data);
2071 if (ret)
2072 return ret;
2073 buf->f_bavail += div_u64(total_free_data, factor);
2074 buf->f_bavail = buf->f_bavail >> bits;
2075
2076 /*
2077 * We calculate the remaining metadata space minus global reserve. If
2078 * this is (supposedly) smaller than zero, there's no space. But this
2079 * does not hold in practice, the exhausted state happens where's still
2080 * some positive delta. So we apply some guesswork and compare the
2081 * delta to a 4M threshold. (Practically observed delta was ~2M.)
2082 *
2083 * We probably cannot calculate the exact threshold value because this
2084 * depends on the internal reservations requested by various
2085 * operations, so some operations that consume a few metadata will
2086 * succeed even if the Avail is zero. But this is better than the other
2087 * way around.
2088 */
2089 thresh = 4 * 1024 * 1024;
2090
2091 if (total_free_meta - thresh < block_rsv->size)
2092 buf->f_bavail = 0;
2093
2094 buf->f_type = BTRFS_SUPER_MAGIC;
2095 buf->f_bsize = dentry->d_sb->s_blocksize;
2096 buf->f_namelen = BTRFS_NAME_LEN;
2097
2098 /* We treat it as constant endianness (it doesn't matter _which_)
2099 because we want the fsid to come out the same whether mounted
2100 on a big-endian or little-endian host */
2101 buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
2102 buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
2103 /* Mask in the root object ID too, to disambiguate subvols */
2104 buf->f_fsid.val[0] ^= BTRFS_I(d_inode(dentry))->root->objectid >> 32;
2105 buf->f_fsid.val[1] ^= BTRFS_I(d_inode(dentry))->root->objectid;
2106
2107 return 0;
2108 }
2109
2110 static void btrfs_kill_super(struct super_block *sb)
2111 {
2112 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2113 kill_anon_super(sb);
2114 free_fs_info(fs_info);
2115 }
2116
2117 static struct file_system_type btrfs_fs_type = {
2118 .owner = THIS_MODULE,
2119 .name = "btrfs",
2120 .mount = btrfs_mount,
2121 .kill_sb = btrfs_kill_super,
2122 .fs_flags = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,
2123 };
2124 MODULE_ALIAS_FS("btrfs");
2125
2126 static int btrfs_control_open(struct inode *inode, struct file *file)
2127 {
2128 /*
2129 * The control file's private_data is used to hold the
2130 * transaction when it is started and is used to keep
2131 * track of whether a transaction is already in progress.
2132 */
2133 file->private_data = NULL;
2134 return 0;
2135 }
2136
2137 /*
2138 * used by btrfsctl to scan devices when no FS is mounted
2139 */
2140 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
2141 unsigned long arg)
2142 {
2143 struct btrfs_ioctl_vol_args *vol;
2144 struct btrfs_fs_devices *fs_devices;
2145 int ret = -ENOTTY;
2146
2147 if (!capable(CAP_SYS_ADMIN))
2148 return -EPERM;
2149
2150 vol = memdup_user((void __user *)arg, sizeof(*vol));
2151 if (IS_ERR(vol))
2152 return PTR_ERR(vol);
2153
2154 switch (cmd) {
2155 case BTRFS_IOC_SCAN_DEV:
2156 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
2157 &btrfs_fs_type, &fs_devices);
2158 break;
2159 case BTRFS_IOC_DEVICES_READY:
2160 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
2161 &btrfs_fs_type, &fs_devices);
2162 if (ret)
2163 break;
2164 ret = !(fs_devices->num_devices == fs_devices->total_devices);
2165 break;
2166 }
2167
2168 kfree(vol);
2169 return ret;
2170 }
2171
2172 static int btrfs_freeze(struct super_block *sb)
2173 {
2174 struct btrfs_trans_handle *trans;
2175 struct btrfs_root *root = btrfs_sb(sb)->tree_root;
2176
2177 trans = btrfs_attach_transaction_barrier(root);
2178 if (IS_ERR(trans)) {
2179 /* no transaction, don't bother */
2180 if (PTR_ERR(trans) == -ENOENT)
2181 return 0;
2182 return PTR_ERR(trans);
2183 }
2184 return btrfs_commit_transaction(trans, root);
2185 }
2186
2187 static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
2188 {
2189 struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
2190 struct btrfs_fs_devices *cur_devices;
2191 struct btrfs_device *dev, *first_dev = NULL;
2192 struct list_head *head;
2193 struct rcu_string *name;
2194
2195 mutex_lock(&fs_info->fs_devices->device_list_mutex);
2196 cur_devices = fs_info->fs_devices;
2197 while (cur_devices) {
2198 head = &cur_devices->devices;
2199 list_for_each_entry(dev, head, dev_list) {
2200 if (dev->missing)
2201 continue;
2202 if (!dev->name)
2203 continue;
2204 if (!first_dev || dev->devid < first_dev->devid)
2205 first_dev = dev;
2206 }
2207 cur_devices = cur_devices->seed;
2208 }
2209
2210 if (first_dev) {
2211 rcu_read_lock();
2212 name = rcu_dereference(first_dev->name);
2213 seq_escape(m, name->str, " \t\n\\");
2214 rcu_read_unlock();
2215 } else {
2216 WARN_ON(1);
2217 }
2218 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2219 return 0;
2220 }
2221
2222 static const struct super_operations btrfs_super_ops = {
2223 .drop_inode = btrfs_drop_inode,
2224 .evict_inode = btrfs_evict_inode,
2225 .put_super = btrfs_put_super,
2226 .sync_fs = btrfs_sync_fs,
2227 .show_options = btrfs_show_options,
2228 .show_devname = btrfs_show_devname,
2229 .write_inode = btrfs_write_inode,
2230 .alloc_inode = btrfs_alloc_inode,
2231 .destroy_inode = btrfs_destroy_inode,
2232 .statfs = btrfs_statfs,
2233 .remount_fs = btrfs_remount,
2234 .freeze_fs = btrfs_freeze,
2235 };
2236
2237 static const struct file_operations btrfs_ctl_fops = {
2238 .open = btrfs_control_open,
2239 .unlocked_ioctl = btrfs_control_ioctl,
2240 .compat_ioctl = btrfs_control_ioctl,
2241 .owner = THIS_MODULE,
2242 .llseek = noop_llseek,
2243 };
2244
2245 static struct miscdevice btrfs_misc = {
2246 .minor = BTRFS_MINOR,
2247 .name = "btrfs-control",
2248 .fops = &btrfs_ctl_fops
2249 };
2250
2251 MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
2252 MODULE_ALIAS("devname:btrfs-control");
2253
2254 static int btrfs_interface_init(void)
2255 {
2256 return misc_register(&btrfs_misc);
2257 }
2258
2259 static void btrfs_interface_exit(void)
2260 {
2261 misc_deregister(&btrfs_misc);
2262 }
2263
2264 static void btrfs_print_info(void)
2265 {
2266 printk(KERN_INFO "Btrfs loaded"
2267 #ifdef CONFIG_BTRFS_DEBUG
2268 ", debug=on"
2269 #endif
2270 #ifdef CONFIG_BTRFS_ASSERT
2271 ", assert=on"
2272 #endif
2273 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
2274 ", integrity-checker=on"
2275 #endif
2276 "\n");
2277 }
2278
2279 static int btrfs_run_sanity_tests(void)
2280 {
2281 int ret;
2282
2283 ret = btrfs_init_test_fs();
2284 if (ret)
2285 return ret;
2286
2287 ret = btrfs_test_free_space_cache();
2288 if (ret)
2289 goto out;
2290 ret = btrfs_test_extent_buffer_operations();
2291 if (ret)
2292 goto out;
2293 ret = btrfs_test_extent_io();
2294 if (ret)
2295 goto out;
2296 ret = btrfs_test_inodes();
2297 if (ret)
2298 goto out;
2299 ret = btrfs_test_qgroups();
2300 if (ret)
2301 goto out;
2302 ret = btrfs_test_free_space_tree();
2303 out:
2304 btrfs_destroy_test_fs();
2305 return ret;
2306 }
2307
2308 static int __init init_btrfs_fs(void)
2309 {
2310 int err;
2311
2312 err = btrfs_hash_init();
2313 if (err)
2314 return err;
2315
2316 btrfs_props_init();
2317
2318 err = btrfs_init_sysfs();
2319 if (err)
2320 goto free_hash;
2321
2322 btrfs_init_compress();
2323
2324 err = btrfs_init_cachep();
2325 if (err)
2326 goto free_compress;
2327
2328 err = extent_io_init();
2329 if (err)
2330 goto free_cachep;
2331
2332 err = extent_map_init();
2333 if (err)
2334 goto free_extent_io;
2335
2336 err = ordered_data_init();
2337 if (err)
2338 goto free_extent_map;
2339
2340 err = btrfs_delayed_inode_init();
2341 if (err)
2342 goto free_ordered_data;
2343
2344 err = btrfs_auto_defrag_init();
2345 if (err)
2346 goto free_delayed_inode;
2347
2348 err = btrfs_delayed_ref_init();
2349 if (err)
2350 goto free_auto_defrag;
2351
2352 err = btrfs_prelim_ref_init();
2353 if (err)
2354 goto free_delayed_ref;
2355
2356 err = btrfs_end_io_wq_init();
2357 if (err)
2358 goto free_prelim_ref;
2359
2360 err = btrfs_interface_init();
2361 if (err)
2362 goto free_end_io_wq;
2363
2364 btrfs_init_lockdep();
2365
2366 btrfs_print_info();
2367
2368 err = btrfs_run_sanity_tests();
2369 if (err)
2370 goto unregister_ioctl;
2371
2372 err = register_filesystem(&btrfs_fs_type);
2373 if (err)
2374 goto unregister_ioctl;
2375
2376 return 0;
2377
2378 unregister_ioctl:
2379 btrfs_interface_exit();
2380 free_end_io_wq:
2381 btrfs_end_io_wq_exit();
2382 free_prelim_ref:
2383 btrfs_prelim_ref_exit();
2384 free_delayed_ref:
2385 btrfs_delayed_ref_exit();
2386 free_auto_defrag:
2387 btrfs_auto_defrag_exit();
2388 free_delayed_inode:
2389 btrfs_delayed_inode_exit();
2390 free_ordered_data:
2391 ordered_data_exit();
2392 free_extent_map:
2393 extent_map_exit();
2394 free_extent_io:
2395 extent_io_exit();
2396 free_cachep:
2397 btrfs_destroy_cachep();
2398 free_compress:
2399 btrfs_exit_compress();
2400 btrfs_exit_sysfs();
2401 free_hash:
2402 btrfs_hash_exit();
2403 return err;
2404 }
2405
2406 static void __exit exit_btrfs_fs(void)
2407 {
2408 btrfs_destroy_cachep();
2409 btrfs_delayed_ref_exit();
2410 btrfs_auto_defrag_exit();
2411 btrfs_delayed_inode_exit();
2412 btrfs_prelim_ref_exit();
2413 ordered_data_exit();
2414 extent_map_exit();
2415 extent_io_exit();
2416 btrfs_interface_exit();
2417 btrfs_end_io_wq_exit();
2418 unregister_filesystem(&btrfs_fs_type);
2419 btrfs_exit_sysfs();
2420 btrfs_cleanup_fs_uuids();
2421 btrfs_exit_compress();
2422 btrfs_hash_exit();
2423 }
2424
2425 late_initcall(init_btrfs_fs);
2426 module_exit(exit_btrfs_fs)
2427
2428 MODULE_LICENSE("GPL");
(deprecated) Btrfs devel tree