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Merge remote-tracking branch 'mmc-uh/next'
[deliverable/linux.git] / fs / btrfs / super.c
1 /*
2 * Copyright (C) 2007 Oracle. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18
19 #include <linux/blkdev.h>
20 #include <linux/module.h>
21 #include <linux/buffer_head.h>
22 #include <linux/fs.h>
23 #include <linux/pagemap.h>
24 #include <linux/highmem.h>
25 #include <linux/time.h>
26 #include <linux/init.h>
27 #include <linux/seq_file.h>
28 #include <linux/string.h>
29 #include <linux/backing-dev.h>
30 #include <linux/mount.h>
31 #include <linux/mpage.h>
32 #include <linux/swap.h>
33 #include <linux/writeback.h>
34 #include <linux/statfs.h>
35 #include <linux/compat.h>
36 #include <linux/parser.h>
37 #include <linux/ctype.h>
38 #include <linux/namei.h>
39 #include <linux/miscdevice.h>
40 #include <linux/magic.h>
41 #include <linux/slab.h>
42 #include <linux/cleancache.h>
43 #include <linux/ratelimit.h>
44 #include <linux/btrfs.h>
45 #include "delayed-inode.h"
46 #include "ctree.h"
47 #include "disk-io.h"
48 #include "transaction.h"
49 #include "btrfs_inode.h"
50 #include "print-tree.h"
51 #include "hash.h"
52 #include "props.h"
53 #include "xattr.h"
54 #include "volumes.h"
55 #include "export.h"
56 #include "compression.h"
57 #include "rcu-string.h"
58 #include "dev-replace.h"
59 #include "free-space-cache.h"
60 #include "backref.h"
61 #include "tests/btrfs-tests.h"
62
63 #include "qgroup.h"
64 #define CREATE_TRACE_POINTS
65 #include <trace/events/btrfs.h>
66
67 static const struct super_operations btrfs_super_ops;
68 static struct file_system_type btrfs_fs_type;
69
70 static int btrfs_remount(struct super_block *sb, int *flags, char *data);
71
72 const char *btrfs_decode_error(int errno)
73 {
74 char *errstr = "unknown";
75
76 switch (errno) {
77 case -EIO:
78 errstr = "IO failure";
79 break;
80 case -ENOMEM:
81 errstr = "Out of memory";
82 break;
83 case -EROFS:
84 errstr = "Readonly filesystem";
85 break;
86 case -EEXIST:
87 errstr = "Object already exists";
88 break;
89 case -ENOSPC:
90 errstr = "No space left";
91 break;
92 case -ENOENT:
93 errstr = "No such entry";
94 break;
95 }
96
97 return errstr;
98 }
99
100 /* 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
188 /*
189 * Use one ratelimit state per log level so that a flood of less important
190 * messages doesn't cause more important ones to be dropped.
191 */
192 static struct ratelimit_state printk_limits[] = {
193 RATELIMIT_STATE_INIT(printk_limits[0], DEFAULT_RATELIMIT_INTERVAL, 100),
194 RATELIMIT_STATE_INIT(printk_limits[1], DEFAULT_RATELIMIT_INTERVAL, 100),
195 RATELIMIT_STATE_INIT(printk_limits[2], DEFAULT_RATELIMIT_INTERVAL, 100),
196 RATELIMIT_STATE_INIT(printk_limits[3], DEFAULT_RATELIMIT_INTERVAL, 100),
197 RATELIMIT_STATE_INIT(printk_limits[4], DEFAULT_RATELIMIT_INTERVAL, 100),
198 RATELIMIT_STATE_INIT(printk_limits[5], DEFAULT_RATELIMIT_INTERVAL, 100),
199 RATELIMIT_STATE_INIT(printk_limits[6], DEFAULT_RATELIMIT_INTERVAL, 100),
200 RATELIMIT_STATE_INIT(printk_limits[7], DEFAULT_RATELIMIT_INTERVAL, 100),
201 };
202
203 void btrfs_printk(const struct btrfs_fs_info *fs_info, const char *fmt, ...)
204 {
205 struct super_block *sb = fs_info->sb;
206 char lvl[4];
207 struct va_format vaf;
208 va_list args;
209 const char *type = logtypes[4];
210 int kern_level;
211 struct ratelimit_state *ratelimit;
212
213 va_start(args, fmt);
214
215 kern_level = printk_get_level(fmt);
216 if (kern_level) {
217 size_t size = printk_skip_level(fmt) - fmt;
218 memcpy(lvl, fmt, size);
219 lvl[size] = '\0';
220 fmt += size;
221 type = logtypes[kern_level - '0'];
222 ratelimit = &printk_limits[kern_level - '0'];
223 } else {
224 *lvl = '\0';
225 /* Default to debug output */
226 ratelimit = &printk_limits[7];
227 }
228
229 vaf.fmt = fmt;
230 vaf.va = &args;
231
232 if (__ratelimit(ratelimit))
233 printk("%sBTRFS %s (device %s): %pV\n", lvl, type, sb->s_id, &vaf);
234
235 va_end(args);
236 }
237 #endif
238
239 /*
240 * We only mark the transaction aborted and then set the file system read-only.
241 * This will prevent new transactions from starting or trying to join this
242 * one.
243 *
244 * This means that error recovery at the call site is limited to freeing
245 * any local memory allocations and passing the error code up without
246 * further cleanup. The transaction should complete as it normally would
247 * in the call path but will return -EIO.
248 *
249 * We'll complete the cleanup in btrfs_end_transaction and
250 * btrfs_commit_transaction.
251 */
252 __cold
253 void __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
254 const char *function,
255 unsigned int line, int errno)
256 {
257 struct btrfs_fs_info *fs_info = trans->fs_info;
258
259 trans->aborted = errno;
260 /* Nothing used. The other threads that have joined this
261 * transaction may be able to continue. */
262 if (!trans->dirty && list_empty(&trans->new_bgs)) {
263 const char *errstr;
264
265 errstr = btrfs_decode_error(errno);
266 btrfs_warn(fs_info,
267 "%s:%d: Aborting unused transaction(%s).",
268 function, line, errstr);
269 return;
270 }
271 ACCESS_ONCE(trans->transaction->aborted) = errno;
272 /* Wake up anybody who may be waiting on this transaction */
273 wake_up(&fs_info->transaction_wait);
274 wake_up(&fs_info->transaction_blocked_wait);
275 __btrfs_handle_fs_error(fs_info, function, line, errno, NULL);
276 }
277 /*
278 * __btrfs_panic decodes unexpected, fatal errors from the caller,
279 * issues an alert, and either panics or BUGs, depending on mount options.
280 */
281 __cold
282 void __btrfs_panic(struct btrfs_fs_info *fs_info, const char *function,
283 unsigned int line, int errno, const char *fmt, ...)
284 {
285 char *s_id = "<unknown>";
286 const char *errstr;
287 struct va_format vaf = { .fmt = fmt };
288 va_list args;
289
290 if (fs_info)
291 s_id = fs_info->sb->s_id;
292
293 va_start(args, fmt);
294 vaf.va = &args;
295
296 errstr = btrfs_decode_error(errno);
297 if (fs_info && (fs_info->mount_opt & BTRFS_MOUNT_PANIC_ON_FATAL_ERROR))
298 panic(KERN_CRIT "BTRFS panic (device %s) in %s:%d: %pV (errno=%d %s)\n",
299 s_id, function, line, &vaf, errno, errstr);
300
301 btrfs_crit(fs_info, "panic in %s:%d: %pV (errno=%d %s)",
302 function, line, &vaf, errno, errstr);
303 va_end(args);
304 /* Caller calls BUG() */
305 }
306
307 static void btrfs_put_super(struct super_block *sb)
308 {
309 close_ctree(btrfs_sb(sb)->tree_root);
310 }
311
312 enum {
313 Opt_degraded, Opt_subvol, Opt_subvolid, Opt_device, Opt_nodatasum,
314 Opt_nodatacow, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd,
315 Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl, Opt_compress,
316 Opt_compress_type, Opt_compress_force, Opt_compress_force_type,
317 Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard,
318 Opt_space_cache, Opt_space_cache_version, Opt_clear_cache,
319 Opt_user_subvol_rm_allowed, Opt_enospc_debug, Opt_subvolrootid,
320 Opt_defrag, Opt_inode_cache, Opt_no_space_cache, Opt_recovery,
321 Opt_skip_balance, Opt_check_integrity,
322 Opt_check_integrity_including_extent_data,
323 Opt_check_integrity_print_mask, Opt_fatal_errors, Opt_rescan_uuid_tree,
324 Opt_commit_interval, Opt_barrier, Opt_nodefrag, Opt_nodiscard,
325 Opt_noenospc_debug, Opt_noflushoncommit, Opt_acl, Opt_datacow,
326 Opt_datasum, Opt_treelog, Opt_noinode_cache, Opt_usebackuproot,
327 Opt_nologreplay, Opt_norecovery,
328 #ifdef CONFIG_BTRFS_DEBUG
329 Opt_fragment_data, Opt_fragment_metadata, Opt_fragment_all,
330 #endif
331 Opt_err,
332 };
333
334 static const match_table_t tokens = {
335 {Opt_degraded, "degraded"},
336 {Opt_subvol, "subvol=%s"},
337 {Opt_subvolid, "subvolid=%s"},
338 {Opt_device, "device=%s"},
339 {Opt_nodatasum, "nodatasum"},
340 {Opt_datasum, "datasum"},
341 {Opt_nodatacow, "nodatacow"},
342 {Opt_datacow, "datacow"},
343 {Opt_nobarrier, "nobarrier"},
344 {Opt_barrier, "barrier"},
345 {Opt_max_inline, "max_inline=%s"},
346 {Opt_alloc_start, "alloc_start=%s"},
347 {Opt_thread_pool, "thread_pool=%d"},
348 {Opt_compress, "compress"},
349 {Opt_compress_type, "compress=%s"},
350 {Opt_compress_force, "compress-force"},
351 {Opt_compress_force_type, "compress-force=%s"},
352 {Opt_ssd, "ssd"},
353 {Opt_ssd_spread, "ssd_spread"},
354 {Opt_nossd, "nossd"},
355 {Opt_acl, "acl"},
356 {Opt_noacl, "noacl"},
357 {Opt_notreelog, "notreelog"},
358 {Opt_treelog, "treelog"},
359 {Opt_nologreplay, "nologreplay"},
360 {Opt_norecovery, "norecovery"},
361 {Opt_flushoncommit, "flushoncommit"},
362 {Opt_noflushoncommit, "noflushoncommit"},
363 {Opt_ratio, "metadata_ratio=%d"},
364 {Opt_discard, "discard"},
365 {Opt_nodiscard, "nodiscard"},
366 {Opt_space_cache, "space_cache"},
367 {Opt_space_cache_version, "space_cache=%s"},
368 {Opt_clear_cache, "clear_cache"},
369 {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
370 {Opt_enospc_debug, "enospc_debug"},
371 {Opt_noenospc_debug, "noenospc_debug"},
372 {Opt_subvolrootid, "subvolrootid=%d"},
373 {Opt_defrag, "autodefrag"},
374 {Opt_nodefrag, "noautodefrag"},
375 {Opt_inode_cache, "inode_cache"},
376 {Opt_noinode_cache, "noinode_cache"},
377 {Opt_no_space_cache, "nospace_cache"},
378 {Opt_recovery, "recovery"}, /* deprecated */
379 {Opt_usebackuproot, "usebackuproot"},
380 {Opt_skip_balance, "skip_balance"},
381 {Opt_check_integrity, "check_int"},
382 {Opt_check_integrity_including_extent_data, "check_int_data"},
383 {Opt_check_integrity_print_mask, "check_int_print_mask=%d"},
384 {Opt_rescan_uuid_tree, "rescan_uuid_tree"},
385 {Opt_fatal_errors, "fatal_errors=%s"},
386 {Opt_commit_interval, "commit=%d"},
387 #ifdef CONFIG_BTRFS_DEBUG
388 {Opt_fragment_data, "fragment=data"},
389 {Opt_fragment_metadata, "fragment=metadata"},
390 {Opt_fragment_all, "fragment=all"},
391 #endif
392 {Opt_err, NULL},
393 };
394
395 /*
396 * Regular mount options parser. Everything that is needed only when
397 * reading in a new superblock is parsed here.
398 * XXX JDM: This needs to be cleaned up for remount.
399 */
400 int btrfs_parse_options(struct btrfs_root *root, char *options,
401 unsigned long new_flags)
402 {
403 struct btrfs_fs_info *info = root->fs_info;
404 substring_t args[MAX_OPT_ARGS];
405 char *p, *num, *orig = NULL;
406 u64 cache_gen;
407 int intarg;
408 int ret = 0;
409 char *compress_type;
410 bool compress_force = false;
411 enum btrfs_compression_type saved_compress_type;
412 bool saved_compress_force;
413 int no_compress = 0;
414
415 cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
416 if (btrfs_fs_compat_ro(root->fs_info, FREE_SPACE_TREE))
417 btrfs_set_opt(info->mount_opt, FREE_SPACE_TREE);
418 else if (cache_gen)
419 btrfs_set_opt(info->mount_opt, SPACE_CACHE);
420
421 /*
422 * Even the options are empty, we still need to do extra check
423 * against new flags
424 */
425 if (!options)
426 goto check;
427
428 /*
429 * strsep changes the string, duplicate it because parse_options
430 * gets called twice
431 */
432 options = kstrdup(options, GFP_NOFS);
433 if (!options)
434 return -ENOMEM;
435
436 orig = options;
437
438 while ((p = strsep(&options, ",")) != NULL) {
439 int token;
440 if (!*p)
441 continue;
442
443 token = match_token(p, tokens, args);
444 switch (token) {
445 case Opt_degraded:
446 btrfs_info(root->fs_info, "allowing degraded mounts");
447 btrfs_set_opt(info->mount_opt, DEGRADED);
448 break;
449 case Opt_subvol:
450 case Opt_subvolid:
451 case Opt_subvolrootid:
452 case Opt_device:
453 /*
454 * These are parsed by btrfs_parse_early_options
455 * and can be happily ignored here.
456 */
457 break;
458 case Opt_nodatasum:
459 btrfs_set_and_info(info, NODATASUM,
460 "setting nodatasum");
461 break;
462 case Opt_datasum:
463 if (btrfs_test_opt(info, NODATASUM)) {
464 if (btrfs_test_opt(info, NODATACOW))
465 btrfs_info(root->fs_info, "setting datasum, datacow enabled");
466 else
467 btrfs_info(root->fs_info, "setting datasum");
468 }
469 btrfs_clear_opt(info->mount_opt, NODATACOW);
470 btrfs_clear_opt(info->mount_opt, NODATASUM);
471 break;
472 case Opt_nodatacow:
473 if (!btrfs_test_opt(info, NODATACOW)) {
474 if (!btrfs_test_opt(info, COMPRESS) ||
475 !btrfs_test_opt(info, FORCE_COMPRESS)) {
476 btrfs_info(root->fs_info,
477 "setting nodatacow, compression disabled");
478 } else {
479 btrfs_info(root->fs_info, "setting nodatacow");
480 }
481 }
482 btrfs_clear_opt(info->mount_opt, COMPRESS);
483 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
484 btrfs_set_opt(info->mount_opt, NODATACOW);
485 btrfs_set_opt(info->mount_opt, NODATASUM);
486 break;
487 case Opt_datacow:
488 btrfs_clear_and_info(info, NODATACOW,
489 "setting datacow");
490 break;
491 case Opt_compress_force:
492 case Opt_compress_force_type:
493 compress_force = true;
494 /* Fallthrough */
495 case Opt_compress:
496 case Opt_compress_type:
497 saved_compress_type = btrfs_test_opt(info,
498 COMPRESS) ?
499 info->compress_type : BTRFS_COMPRESS_NONE;
500 saved_compress_force =
501 btrfs_test_opt(info, FORCE_COMPRESS);
502 if (token == Opt_compress ||
503 token == Opt_compress_force ||
504 strcmp(args[0].from, "zlib") == 0) {
505 compress_type = "zlib";
506 info->compress_type = BTRFS_COMPRESS_ZLIB;
507 btrfs_set_opt(info->mount_opt, COMPRESS);
508 btrfs_clear_opt(info->mount_opt, NODATACOW);
509 btrfs_clear_opt(info->mount_opt, NODATASUM);
510 no_compress = 0;
511 } else if (strcmp(args[0].from, "lzo") == 0) {
512 compress_type = "lzo";
513 info->compress_type = BTRFS_COMPRESS_LZO;
514 btrfs_set_opt(info->mount_opt, COMPRESS);
515 btrfs_clear_opt(info->mount_opt, NODATACOW);
516 btrfs_clear_opt(info->mount_opt, NODATASUM);
517 btrfs_set_fs_incompat(info, COMPRESS_LZO);
518 no_compress = 0;
519 } else if (strncmp(args[0].from, "no", 2) == 0) {
520 compress_type = "no";
521 btrfs_clear_opt(info->mount_opt, COMPRESS);
522 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
523 compress_force = false;
524 no_compress++;
525 } else {
526 ret = -EINVAL;
527 goto out;
528 }
529
530 if (compress_force) {
531 btrfs_set_opt(info->mount_opt, FORCE_COMPRESS);
532 } else {
533 /*
534 * If we remount from compress-force=xxx to
535 * compress=xxx, we need clear FORCE_COMPRESS
536 * flag, otherwise, there is no way for users
537 * to disable forcible compression separately.
538 */
539 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
540 }
541 if ((btrfs_test_opt(info, COMPRESS) &&
542 (info->compress_type != saved_compress_type ||
543 compress_force != saved_compress_force)) ||
544 (!btrfs_test_opt(info, COMPRESS) &&
545 no_compress == 1)) {
546 btrfs_info(root->fs_info,
547 "%s %s compression",
548 (compress_force) ? "force" : "use",
549 compress_type);
550 }
551 compress_force = false;
552 break;
553 case Opt_ssd:
554 btrfs_set_and_info(info, SSD,
555 "use ssd allocation scheme");
556 break;
557 case Opt_ssd_spread:
558 btrfs_set_and_info(info, SSD_SPREAD,
559 "use spread ssd allocation scheme");
560 btrfs_set_opt(info->mount_opt, SSD);
561 break;
562 case Opt_nossd:
563 btrfs_set_and_info(info, NOSSD,
564 "not using ssd allocation scheme");
565 btrfs_clear_opt(info->mount_opt, SSD);
566 break;
567 case Opt_barrier:
568 btrfs_clear_and_info(info, NOBARRIER,
569 "turning on barriers");
570 break;
571 case Opt_nobarrier:
572 btrfs_set_and_info(info, NOBARRIER,
573 "turning off barriers");
574 break;
575 case Opt_thread_pool:
576 ret = match_int(&args[0], &intarg);
577 if (ret) {
578 goto out;
579 } else if (intarg > 0) {
580 info->thread_pool_size = intarg;
581 } else {
582 ret = -EINVAL;
583 goto out;
584 }
585 break;
586 case Opt_max_inline:
587 num = match_strdup(&args[0]);
588 if (num) {
589 info->max_inline = memparse(num, NULL);
590 kfree(num);
591
592 if (info->max_inline) {
593 info->max_inline = min_t(u64,
594 info->max_inline,
595 root->sectorsize);
596 }
597 btrfs_info(root->fs_info, "max_inline at %llu",
598 info->max_inline);
599 } else {
600 ret = -ENOMEM;
601 goto out;
602 }
603 break;
604 case Opt_alloc_start:
605 num = match_strdup(&args[0]);
606 if (num) {
607 mutex_lock(&info->chunk_mutex);
608 info->alloc_start = memparse(num, NULL);
609 mutex_unlock(&info->chunk_mutex);
610 kfree(num);
611 btrfs_info(root->fs_info, "allocations start at %llu",
612 info->alloc_start);
613 } else {
614 ret = -ENOMEM;
615 goto out;
616 }
617 break;
618 case Opt_acl:
619 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
620 root->fs_info->sb->s_flags |= MS_POSIXACL;
621 break;
622 #else
623 btrfs_err(root->fs_info,
624 "support for ACL not compiled in!");
625 ret = -EINVAL;
626 goto out;
627 #endif
628 case Opt_noacl:
629 root->fs_info->sb->s_flags &= ~MS_POSIXACL;
630 break;
631 case Opt_notreelog:
632 btrfs_set_and_info(info, NOTREELOG,
633 "disabling tree log");
634 break;
635 case Opt_treelog:
636 btrfs_clear_and_info(info, NOTREELOG,
637 "enabling tree log");
638 break;
639 case Opt_norecovery:
640 case Opt_nologreplay:
641 btrfs_set_and_info(info, NOLOGREPLAY,
642 "disabling log replay at mount time");
643 break;
644 case Opt_flushoncommit:
645 btrfs_set_and_info(info, FLUSHONCOMMIT,
646 "turning on flush-on-commit");
647 break;
648 case Opt_noflushoncommit:
649 btrfs_clear_and_info(info, FLUSHONCOMMIT,
650 "turning off flush-on-commit");
651 break;
652 case Opt_ratio:
653 ret = match_int(&args[0], &intarg);
654 if (ret) {
655 goto out;
656 } else if (intarg >= 0) {
657 info->metadata_ratio = intarg;
658 btrfs_info(root->fs_info, "metadata ratio %d",
659 info->metadata_ratio);
660 } else {
661 ret = -EINVAL;
662 goto out;
663 }
664 break;
665 case Opt_discard:
666 btrfs_set_and_info(info, DISCARD,
667 "turning on discard");
668 break;
669 case Opt_nodiscard:
670 btrfs_clear_and_info(info, DISCARD,
671 "turning off discard");
672 break;
673 case Opt_space_cache:
674 case Opt_space_cache_version:
675 if (token == Opt_space_cache ||
676 strcmp(args[0].from, "v1") == 0) {
677 btrfs_clear_opt(root->fs_info->mount_opt,
678 FREE_SPACE_TREE);
679 btrfs_set_and_info(info, SPACE_CACHE,
680 "enabling disk space caching");
681 } else if (strcmp(args[0].from, "v2") == 0) {
682 btrfs_clear_opt(root->fs_info->mount_opt,
683 SPACE_CACHE);
684 btrfs_set_and_info(info,
685 FREE_SPACE_TREE,
686 "enabling free space tree");
687 } else {
688 ret = -EINVAL;
689 goto out;
690 }
691 break;
692 case Opt_rescan_uuid_tree:
693 btrfs_set_opt(info->mount_opt, RESCAN_UUID_TREE);
694 break;
695 case Opt_no_space_cache:
696 if (btrfs_test_opt(info, SPACE_CACHE)) {
697 btrfs_clear_and_info(info,
698 SPACE_CACHE,
699 "disabling disk space caching");
700 }
701 if (btrfs_test_opt(info, FREE_SPACE_TREE)) {
702 btrfs_clear_and_info(info,
703 FREE_SPACE_TREE,
704 "disabling free space tree");
705 }
706 break;
707 case Opt_inode_cache:
708 btrfs_set_pending_and_info(info, INODE_MAP_CACHE,
709 "enabling inode map caching");
710 break;
711 case Opt_noinode_cache:
712 btrfs_clear_pending_and_info(info, INODE_MAP_CACHE,
713 "disabling inode map caching");
714 break;
715 case Opt_clear_cache:
716 btrfs_set_and_info(info, CLEAR_CACHE,
717 "force clearing of disk cache");
718 break;
719 case Opt_user_subvol_rm_allowed:
720 btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
721 break;
722 case Opt_enospc_debug:
723 btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
724 break;
725 case Opt_noenospc_debug:
726 btrfs_clear_opt(info->mount_opt, ENOSPC_DEBUG);
727 break;
728 case Opt_defrag:
729 btrfs_set_and_info(info, AUTO_DEFRAG,
730 "enabling auto defrag");
731 break;
732 case Opt_nodefrag:
733 btrfs_clear_and_info(info, AUTO_DEFRAG,
734 "disabling auto defrag");
735 break;
736 case Opt_recovery:
737 btrfs_warn(root->fs_info,
738 "'recovery' is deprecated, use 'usebackuproot' instead");
739 case Opt_usebackuproot:
740 btrfs_info(root->fs_info,
741 "trying to use backup root at mount time");
742 btrfs_set_opt(info->mount_opt, USEBACKUPROOT);
743 break;
744 case Opt_skip_balance:
745 btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
746 break;
747 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
748 case Opt_check_integrity_including_extent_data:
749 btrfs_info(root->fs_info,
750 "enabling check integrity including extent data");
751 btrfs_set_opt(info->mount_opt,
752 CHECK_INTEGRITY_INCLUDING_EXTENT_DATA);
753 btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
754 break;
755 case Opt_check_integrity:
756 btrfs_info(root->fs_info, "enabling check integrity");
757 btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
758 break;
759 case Opt_check_integrity_print_mask:
760 ret = match_int(&args[0], &intarg);
761 if (ret) {
762 goto out;
763 } else if (intarg >= 0) {
764 info->check_integrity_print_mask = intarg;
765 btrfs_info(root->fs_info, "check_integrity_print_mask 0x%x",
766 info->check_integrity_print_mask);
767 } else {
768 ret = -EINVAL;
769 goto out;
770 }
771 break;
772 #else
773 case Opt_check_integrity_including_extent_data:
774 case Opt_check_integrity:
775 case Opt_check_integrity_print_mask:
776 btrfs_err(root->fs_info,
777 "support for check_integrity* not compiled in!");
778 ret = -EINVAL;
779 goto out;
780 #endif
781 case Opt_fatal_errors:
782 if (strcmp(args[0].from, "panic") == 0)
783 btrfs_set_opt(info->mount_opt,
784 PANIC_ON_FATAL_ERROR);
785 else if (strcmp(args[0].from, "bug") == 0)
786 btrfs_clear_opt(info->mount_opt,
787 PANIC_ON_FATAL_ERROR);
788 else {
789 ret = -EINVAL;
790 goto out;
791 }
792 break;
793 case Opt_commit_interval:
794 intarg = 0;
795 ret = match_int(&args[0], &intarg);
796 if (ret < 0) {
797 btrfs_err(root->fs_info, "invalid commit interval");
798 ret = -EINVAL;
799 goto out;
800 }
801 if (intarg > 0) {
802 if (intarg > 300) {
803 btrfs_warn(root->fs_info, "excessive commit interval %d",
804 intarg);
805 }
806 info->commit_interval = intarg;
807 } else {
808 btrfs_info(root->fs_info, "using default commit interval %ds",
809 BTRFS_DEFAULT_COMMIT_INTERVAL);
810 info->commit_interval = BTRFS_DEFAULT_COMMIT_INTERVAL;
811 }
812 break;
813 #ifdef CONFIG_BTRFS_DEBUG
814 case Opt_fragment_all:
815 btrfs_info(root->fs_info, "fragmenting all space");
816 btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
817 btrfs_set_opt(info->mount_opt, FRAGMENT_METADATA);
818 break;
819 case Opt_fragment_metadata:
820 btrfs_info(root->fs_info, "fragmenting metadata");
821 btrfs_set_opt(info->mount_opt,
822 FRAGMENT_METADATA);
823 break;
824 case Opt_fragment_data:
825 btrfs_info(root->fs_info, "fragmenting data");
826 btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
827 break;
828 #endif
829 case Opt_err:
830 btrfs_info(root->fs_info, "unrecognized mount option '%s'", p);
831 ret = -EINVAL;
832 goto out;
833 default:
834 break;
835 }
836 }
837 check:
838 /*
839 * Extra check for current option against current flag
840 */
841 if (btrfs_test_opt(info, NOLOGREPLAY) && !(new_flags & MS_RDONLY)) {
842 btrfs_err(root->fs_info,
843 "nologreplay must be used with ro mount option");
844 ret = -EINVAL;
845 }
846 out:
847 if (btrfs_fs_compat_ro(root->fs_info, FREE_SPACE_TREE) &&
848 !btrfs_test_opt(info, FREE_SPACE_TREE) &&
849 !btrfs_test_opt(info, CLEAR_CACHE)) {
850 btrfs_err(root->fs_info, "cannot disable free space tree");
851 ret = -EINVAL;
852
853 }
854 if (!ret && btrfs_test_opt(info, SPACE_CACHE))
855 btrfs_info(root->fs_info, "disk space caching is enabled");
856 if (!ret && btrfs_test_opt(info, FREE_SPACE_TREE))
857 btrfs_info(root->fs_info, "using free space tree");
858 kfree(orig);
859 return ret;
860 }
861
862 /*
863 * Parse mount options that are required early in the mount process.
864 *
865 * All other options will be parsed on much later in the mount process and
866 * only when we need to allocate a new super block.
867 */
868 static int btrfs_parse_early_options(const char *options, fmode_t flags,
869 void *holder, char **subvol_name, u64 *subvol_objectid,
870 struct btrfs_fs_devices **fs_devices)
871 {
872 substring_t args[MAX_OPT_ARGS];
873 char *device_name, *opts, *orig, *p;
874 char *num = NULL;
875 int error = 0;
876
877 if (!options)
878 return 0;
879
880 /*
881 * strsep changes the string, duplicate it because parse_options
882 * gets called twice
883 */
884 opts = kstrdup(options, GFP_KERNEL);
885 if (!opts)
886 return -ENOMEM;
887 orig = opts;
888
889 while ((p = strsep(&opts, ",")) != NULL) {
890 int token;
891 if (!*p)
892 continue;
893
894 token = match_token(p, tokens, args);
895 switch (token) {
896 case Opt_subvol:
897 kfree(*subvol_name);
898 *subvol_name = match_strdup(&args[0]);
899 if (!*subvol_name) {
900 error = -ENOMEM;
901 goto out;
902 }
903 break;
904 case Opt_subvolid:
905 num = match_strdup(&args[0]);
906 if (num) {
907 *subvol_objectid = memparse(num, NULL);
908 kfree(num);
909 /* we want the original fs_tree */
910 if (!*subvol_objectid)
911 *subvol_objectid =
912 BTRFS_FS_TREE_OBJECTID;
913 } else {
914 error = -EINVAL;
915 goto out;
916 }
917 break;
918 case Opt_subvolrootid:
919 printk(KERN_WARNING
920 "BTRFS: 'subvolrootid' mount option is deprecated and has "
921 "no effect\n");
922 break;
923 case Opt_device:
924 device_name = match_strdup(&args[0]);
925 if (!device_name) {
926 error = -ENOMEM;
927 goto out;
928 }
929 error = btrfs_scan_one_device(device_name,
930 flags, holder, fs_devices);
931 kfree(device_name);
932 if (error)
933 goto out;
934 break;
935 default:
936 break;
937 }
938 }
939
940 out:
941 kfree(orig);
942 return error;
943 }
944
945 static char *get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
946 u64 subvol_objectid)
947 {
948 struct btrfs_root *root = fs_info->tree_root;
949 struct btrfs_root *fs_root;
950 struct btrfs_root_ref *root_ref;
951 struct btrfs_inode_ref *inode_ref;
952 struct btrfs_key key;
953 struct btrfs_path *path = NULL;
954 char *name = NULL, *ptr;
955 u64 dirid;
956 int len;
957 int ret;
958
959 path = btrfs_alloc_path();
960 if (!path) {
961 ret = -ENOMEM;
962 goto err;
963 }
964 path->leave_spinning = 1;
965
966 name = kmalloc(PATH_MAX, GFP_NOFS);
967 if (!name) {
968 ret = -ENOMEM;
969 goto err;
970 }
971 ptr = name + PATH_MAX - 1;
972 ptr[0] = '\0';
973
974 /*
975 * Walk up the subvolume trees in the tree of tree roots by root
976 * backrefs until we hit the top-level subvolume.
977 */
978 while (subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
979 key.objectid = subvol_objectid;
980 key.type = BTRFS_ROOT_BACKREF_KEY;
981 key.offset = (u64)-1;
982
983 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
984 if (ret < 0) {
985 goto err;
986 } else if (ret > 0) {
987 ret = btrfs_previous_item(root, path, subvol_objectid,
988 BTRFS_ROOT_BACKREF_KEY);
989 if (ret < 0) {
990 goto err;
991 } else if (ret > 0) {
992 ret = -ENOENT;
993 goto err;
994 }
995 }
996
997 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
998 subvol_objectid = key.offset;
999
1000 root_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
1001 struct btrfs_root_ref);
1002 len = btrfs_root_ref_name_len(path->nodes[0], root_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)(root_ref + 1), len);
1010 ptr[0] = '/';
1011 dirid = btrfs_root_ref_dirid(path->nodes[0], root_ref);
1012 btrfs_release_path(path);
1013
1014 key.objectid = subvol_objectid;
1015 key.type = BTRFS_ROOT_ITEM_KEY;
1016 key.offset = (u64)-1;
1017 fs_root = btrfs_read_fs_root_no_name(fs_info, &key);
1018 if (IS_ERR(fs_root)) {
1019 ret = PTR_ERR(fs_root);
1020 goto err;
1021 }
1022
1023 /*
1024 * Walk up the filesystem tree by inode refs until we hit the
1025 * root directory.
1026 */
1027 while (dirid != BTRFS_FIRST_FREE_OBJECTID) {
1028 key.objectid = dirid;
1029 key.type = BTRFS_INODE_REF_KEY;
1030 key.offset = (u64)-1;
1031
1032 ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0);
1033 if (ret < 0) {
1034 goto err;
1035 } else if (ret > 0) {
1036 ret = btrfs_previous_item(fs_root, path, dirid,
1037 BTRFS_INODE_REF_KEY);
1038 if (ret < 0) {
1039 goto err;
1040 } else if (ret > 0) {
1041 ret = -ENOENT;
1042 goto err;
1043 }
1044 }
1045
1046 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1047 dirid = key.offset;
1048
1049 inode_ref = btrfs_item_ptr(path->nodes[0],
1050 path->slots[0],
1051 struct btrfs_inode_ref);
1052 len = btrfs_inode_ref_name_len(path->nodes[0],
1053 inode_ref);
1054 ptr -= len + 1;
1055 if (ptr < name) {
1056 ret = -ENAMETOOLONG;
1057 goto err;
1058 }
1059 read_extent_buffer(path->nodes[0], ptr + 1,
1060 (unsigned long)(inode_ref + 1), len);
1061 ptr[0] = '/';
1062 btrfs_release_path(path);
1063 }
1064 }
1065
1066 btrfs_free_path(path);
1067 if (ptr == name + PATH_MAX - 1) {
1068 name[0] = '/';
1069 name[1] = '\0';
1070 } else {
1071 memmove(name, ptr, name + PATH_MAX - ptr);
1072 }
1073 return name;
1074
1075 err:
1076 btrfs_free_path(path);
1077 kfree(name);
1078 return ERR_PTR(ret);
1079 }
1080
1081 static int get_default_subvol_objectid(struct btrfs_fs_info *fs_info, u64 *objectid)
1082 {
1083 struct btrfs_root *root = fs_info->tree_root;
1084 struct btrfs_dir_item *di;
1085 struct btrfs_path *path;
1086 struct btrfs_key location;
1087 u64 dir_id;
1088
1089 path = btrfs_alloc_path();
1090 if (!path)
1091 return -ENOMEM;
1092 path->leave_spinning = 1;
1093
1094 /*
1095 * Find the "default" dir item which points to the root item that we
1096 * will mount by default if we haven't been given a specific subvolume
1097 * to mount.
1098 */
1099 dir_id = btrfs_super_root_dir(fs_info->super_copy);
1100 di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
1101 if (IS_ERR(di)) {
1102 btrfs_free_path(path);
1103 return PTR_ERR(di);
1104 }
1105 if (!di) {
1106 /*
1107 * Ok the default dir item isn't there. This is weird since
1108 * it's always been there, but don't freak out, just try and
1109 * mount the top-level subvolume.
1110 */
1111 btrfs_free_path(path);
1112 *objectid = BTRFS_FS_TREE_OBJECTID;
1113 return 0;
1114 }
1115
1116 btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
1117 btrfs_free_path(path);
1118 *objectid = location.objectid;
1119 return 0;
1120 }
1121
1122 static int btrfs_fill_super(struct super_block *sb,
1123 struct btrfs_fs_devices *fs_devices,
1124 void *data, int silent)
1125 {
1126 struct inode *inode;
1127 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1128 struct btrfs_key key;
1129 int err;
1130
1131 sb->s_maxbytes = MAX_LFS_FILESIZE;
1132 sb->s_magic = BTRFS_SUPER_MAGIC;
1133 sb->s_op = &btrfs_super_ops;
1134 sb->s_d_op = &btrfs_dentry_operations;
1135 sb->s_export_op = &btrfs_export_ops;
1136 sb->s_xattr = btrfs_xattr_handlers;
1137 sb->s_time_gran = 1;
1138 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
1139 sb->s_flags |= MS_POSIXACL;
1140 #endif
1141 sb->s_flags |= MS_I_VERSION;
1142 sb->s_iflags |= SB_I_CGROUPWB;
1143 err = open_ctree(sb, fs_devices, (char *)data);
1144 if (err) {
1145 printk(KERN_ERR "BTRFS: open_ctree failed\n");
1146 return err;
1147 }
1148
1149 key.objectid = BTRFS_FIRST_FREE_OBJECTID;
1150 key.type = BTRFS_INODE_ITEM_KEY;
1151 key.offset = 0;
1152 inode = btrfs_iget(sb, &key, fs_info->fs_root, NULL);
1153 if (IS_ERR(inode)) {
1154 err = PTR_ERR(inode);
1155 goto fail_close;
1156 }
1157
1158 sb->s_root = d_make_root(inode);
1159 if (!sb->s_root) {
1160 err = -ENOMEM;
1161 goto fail_close;
1162 }
1163
1164 save_mount_options(sb, data);
1165 cleancache_init_fs(sb);
1166 sb->s_flags |= MS_ACTIVE;
1167 return 0;
1168
1169 fail_close:
1170 close_ctree(fs_info->tree_root);
1171 return err;
1172 }
1173
1174 int btrfs_sync_fs(struct super_block *sb, int wait)
1175 {
1176 struct btrfs_trans_handle *trans;
1177 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1178 struct btrfs_root *root = fs_info->tree_root;
1179
1180 trace_btrfs_sync_fs(fs_info, wait);
1181
1182 if (!wait) {
1183 filemap_flush(fs_info->btree_inode->i_mapping);
1184 return 0;
1185 }
1186
1187 btrfs_wait_ordered_roots(fs_info, -1, 0, (u64)-1);
1188
1189 trans = btrfs_attach_transaction_barrier(root);
1190 if (IS_ERR(trans)) {
1191 /* no transaction, don't bother */
1192 if (PTR_ERR(trans) == -ENOENT) {
1193 /*
1194 * Exit unless we have some pending changes
1195 * that need to go through commit
1196 */
1197 if (fs_info->pending_changes == 0)
1198 return 0;
1199 /*
1200 * A non-blocking test if the fs is frozen. We must not
1201 * start a new transaction here otherwise a deadlock
1202 * happens. The pending operations are delayed to the
1203 * next commit after thawing.
1204 */
1205 if (__sb_start_write(sb, SB_FREEZE_WRITE, false))
1206 __sb_end_write(sb, SB_FREEZE_WRITE);
1207 else
1208 return 0;
1209 trans = btrfs_start_transaction(root, 0);
1210 }
1211 if (IS_ERR(trans))
1212 return PTR_ERR(trans);
1213 }
1214 return btrfs_commit_transaction(trans, root);
1215 }
1216
1217 static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
1218 {
1219 struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
1220 struct btrfs_root *root = info->tree_root;
1221 char *compress_type;
1222
1223 if (btrfs_test_opt(info, DEGRADED))
1224 seq_puts(seq, ",degraded");
1225 if (btrfs_test_opt(info, NODATASUM))
1226 seq_puts(seq, ",nodatasum");
1227 if (btrfs_test_opt(info, NODATACOW))
1228 seq_puts(seq, ",nodatacow");
1229 if (btrfs_test_opt(info, NOBARRIER))
1230 seq_puts(seq, ",nobarrier");
1231 if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE)
1232 seq_printf(seq, ",max_inline=%llu", info->max_inline);
1233 if (info->alloc_start != 0)
1234 seq_printf(seq, ",alloc_start=%llu", info->alloc_start);
1235 if (info->thread_pool_size != min_t(unsigned long,
1236 num_online_cpus() + 2, 8))
1237 seq_printf(seq, ",thread_pool=%d", info->thread_pool_size);
1238 if (btrfs_test_opt(info, COMPRESS)) {
1239 if (info->compress_type == BTRFS_COMPRESS_ZLIB)
1240 compress_type = "zlib";
1241 else
1242 compress_type = "lzo";
1243 if (btrfs_test_opt(info, FORCE_COMPRESS))
1244 seq_printf(seq, ",compress-force=%s", compress_type);
1245 else
1246 seq_printf(seq, ",compress=%s", compress_type);
1247 }
1248 if (btrfs_test_opt(info, NOSSD))
1249 seq_puts(seq, ",nossd");
1250 if (btrfs_test_opt(info, SSD_SPREAD))
1251 seq_puts(seq, ",ssd_spread");
1252 else if (btrfs_test_opt(info, SSD))
1253 seq_puts(seq, ",ssd");
1254 if (btrfs_test_opt(info, NOTREELOG))
1255 seq_puts(seq, ",notreelog");
1256 if (btrfs_test_opt(info, NOLOGREPLAY))
1257 seq_puts(seq, ",nologreplay");
1258 if (btrfs_test_opt(info, FLUSHONCOMMIT))
1259 seq_puts(seq, ",flushoncommit");
1260 if (btrfs_test_opt(info, DISCARD))
1261 seq_puts(seq, ",discard");
1262 if (!(root->fs_info->sb->s_flags & MS_POSIXACL))
1263 seq_puts(seq, ",noacl");
1264 if (btrfs_test_opt(info, SPACE_CACHE))
1265 seq_puts(seq, ",space_cache");
1266 else if (btrfs_test_opt(info, FREE_SPACE_TREE))
1267 seq_puts(seq, ",space_cache=v2");
1268 else
1269 seq_puts(seq, ",nospace_cache");
1270 if (btrfs_test_opt(info, RESCAN_UUID_TREE))
1271 seq_puts(seq, ",rescan_uuid_tree");
1272 if (btrfs_test_opt(info, CLEAR_CACHE))
1273 seq_puts(seq, ",clear_cache");
1274 if (btrfs_test_opt(info, USER_SUBVOL_RM_ALLOWED))
1275 seq_puts(seq, ",user_subvol_rm_allowed");
1276 if (btrfs_test_opt(info, ENOSPC_DEBUG))
1277 seq_puts(seq, ",enospc_debug");
1278 if (btrfs_test_opt(info, AUTO_DEFRAG))
1279 seq_puts(seq, ",autodefrag");
1280 if (btrfs_test_opt(info, INODE_MAP_CACHE))
1281 seq_puts(seq, ",inode_cache");
1282 if (btrfs_test_opt(info, SKIP_BALANCE))
1283 seq_puts(seq, ",skip_balance");
1284 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
1285 if (btrfs_test_opt(info, CHECK_INTEGRITY_INCLUDING_EXTENT_DATA))
1286 seq_puts(seq, ",check_int_data");
1287 else if (btrfs_test_opt(info, CHECK_INTEGRITY))
1288 seq_puts(seq, ",check_int");
1289 if (info->check_integrity_print_mask)
1290 seq_printf(seq, ",check_int_print_mask=%d",
1291 info->check_integrity_print_mask);
1292 #endif
1293 if (info->metadata_ratio)
1294 seq_printf(seq, ",metadata_ratio=%d",
1295 info->metadata_ratio);
1296 if (btrfs_test_opt(info, PANIC_ON_FATAL_ERROR))
1297 seq_puts(seq, ",fatal_errors=panic");
1298 if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL)
1299 seq_printf(seq, ",commit=%d", info->commit_interval);
1300 #ifdef CONFIG_BTRFS_DEBUG
1301 if (btrfs_test_opt(info, FRAGMENT_DATA))
1302 seq_puts(seq, ",fragment=data");
1303 if (btrfs_test_opt(info, FRAGMENT_METADATA))
1304 seq_puts(seq, ",fragment=metadata");
1305 #endif
1306 seq_printf(seq, ",subvolid=%llu",
1307 BTRFS_I(d_inode(dentry))->root->root_key.objectid);
1308 seq_puts(seq, ",subvol=");
1309 seq_dentry(seq, dentry, " \t\n\\");
1310 return 0;
1311 }
1312
1313 static int btrfs_test_super(struct super_block *s, void *data)
1314 {
1315 struct btrfs_fs_info *p = data;
1316 struct btrfs_fs_info *fs_info = btrfs_sb(s);
1317
1318 return fs_info->fs_devices == p->fs_devices;
1319 }
1320
1321 static int btrfs_set_super(struct super_block *s, void *data)
1322 {
1323 int err = set_anon_super(s, data);
1324 if (!err)
1325 s->s_fs_info = data;
1326 return err;
1327 }
1328
1329 /*
1330 * subvolumes are identified by ino 256
1331 */
1332 static inline int is_subvolume_inode(struct inode *inode)
1333 {
1334 if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
1335 return 1;
1336 return 0;
1337 }
1338
1339 /*
1340 * This will add subvolid=0 to the argument string while removing any subvol=
1341 * and subvolid= arguments to make sure we get the top-level root for path
1342 * walking to the subvol we want.
1343 */
1344 static char *setup_root_args(char *args)
1345 {
1346 char *buf, *dst, *sep;
1347
1348 if (!args)
1349 return kstrdup("subvolid=0", GFP_NOFS);
1350
1351 /* The worst case is that we add ",subvolid=0" to the end. */
1352 buf = dst = kmalloc(strlen(args) + strlen(",subvolid=0") + 1, GFP_NOFS);
1353 if (!buf)
1354 return NULL;
1355
1356 while (1) {
1357 sep = strchrnul(args, ',');
1358 if (!strstarts(args, "subvol=") &&
1359 !strstarts(args, "subvolid=")) {
1360 memcpy(dst, args, sep - args);
1361 dst += sep - args;
1362 *dst++ = ',';
1363 }
1364 if (*sep)
1365 args = sep + 1;
1366 else
1367 break;
1368 }
1369 strcpy(dst, "subvolid=0");
1370
1371 return buf;
1372 }
1373
1374 static struct dentry *mount_subvol(const char *subvol_name, u64 subvol_objectid,
1375 int flags, const char *device_name,
1376 char *data)
1377 {
1378 struct dentry *root;
1379 struct vfsmount *mnt = NULL;
1380 char *newargs;
1381 int ret;
1382
1383 newargs = setup_root_args(data);
1384 if (!newargs) {
1385 root = ERR_PTR(-ENOMEM);
1386 goto out;
1387 }
1388
1389 mnt = vfs_kern_mount(&btrfs_fs_type, flags, device_name, newargs);
1390 if (PTR_ERR_OR_ZERO(mnt) == -EBUSY) {
1391 if (flags & MS_RDONLY) {
1392 mnt = vfs_kern_mount(&btrfs_fs_type, flags & ~MS_RDONLY,
1393 device_name, newargs);
1394 } else {
1395 mnt = vfs_kern_mount(&btrfs_fs_type, flags | MS_RDONLY,
1396 device_name, newargs);
1397 if (IS_ERR(mnt)) {
1398 root = ERR_CAST(mnt);
1399 mnt = NULL;
1400 goto out;
1401 }
1402
1403 down_write(&mnt->mnt_sb->s_umount);
1404 ret = btrfs_remount(mnt->mnt_sb, &flags, NULL);
1405 up_write(&mnt->mnt_sb->s_umount);
1406 if (ret < 0) {
1407 root = ERR_PTR(ret);
1408 goto out;
1409 }
1410 }
1411 }
1412 if (IS_ERR(mnt)) {
1413 root = ERR_CAST(mnt);
1414 mnt = NULL;
1415 goto out;
1416 }
1417
1418 if (!subvol_name) {
1419 if (!subvol_objectid) {
1420 ret = get_default_subvol_objectid(btrfs_sb(mnt->mnt_sb),
1421 &subvol_objectid);
1422 if (ret) {
1423 root = ERR_PTR(ret);
1424 goto out;
1425 }
1426 }
1427 subvol_name = get_subvol_name_from_objectid(btrfs_sb(mnt->mnt_sb),
1428 subvol_objectid);
1429 if (IS_ERR(subvol_name)) {
1430 root = ERR_CAST(subvol_name);
1431 subvol_name = NULL;
1432 goto out;
1433 }
1434
1435 }
1436
1437 root = mount_subtree(mnt, subvol_name);
1438 /* mount_subtree() drops our reference on the vfsmount. */
1439 mnt = NULL;
1440
1441 if (!IS_ERR(root)) {
1442 struct super_block *s = root->d_sb;
1443 struct inode *root_inode = d_inode(root);
1444 u64 root_objectid = BTRFS_I(root_inode)->root->root_key.objectid;
1445
1446 ret = 0;
1447 if (!is_subvolume_inode(root_inode)) {
1448 pr_err("BTRFS: '%s' is not a valid subvolume\n",
1449 subvol_name);
1450 ret = -EINVAL;
1451 }
1452 if (subvol_objectid && root_objectid != subvol_objectid) {
1453 /*
1454 * This will also catch a race condition where a
1455 * subvolume which was passed by ID is renamed and
1456 * another subvolume is renamed over the old location.
1457 */
1458 pr_err("BTRFS: subvol '%s' does not match subvolid %llu\n",
1459 subvol_name, subvol_objectid);
1460 ret = -EINVAL;
1461 }
1462 if (ret) {
1463 dput(root);
1464 root = ERR_PTR(ret);
1465 deactivate_locked_super(s);
1466 }
1467 }
1468
1469 out:
1470 mntput(mnt);
1471 kfree(newargs);
1472 kfree(subvol_name);
1473 return root;
1474 }
1475
1476 static int parse_security_options(char *orig_opts,
1477 struct security_mnt_opts *sec_opts)
1478 {
1479 char *secdata = NULL;
1480 int ret = 0;
1481
1482 secdata = alloc_secdata();
1483 if (!secdata)
1484 return -ENOMEM;
1485 ret = security_sb_copy_data(orig_opts, secdata);
1486 if (ret) {
1487 free_secdata(secdata);
1488 return ret;
1489 }
1490 ret = security_sb_parse_opts_str(secdata, sec_opts);
1491 free_secdata(secdata);
1492 return ret;
1493 }
1494
1495 static int setup_security_options(struct btrfs_fs_info *fs_info,
1496 struct super_block *sb,
1497 struct security_mnt_opts *sec_opts)
1498 {
1499 int ret = 0;
1500
1501 /*
1502 * Call security_sb_set_mnt_opts() to check whether new sec_opts
1503 * is valid.
1504 */
1505 ret = security_sb_set_mnt_opts(sb, sec_opts, 0, NULL);
1506 if (ret)
1507 return ret;
1508
1509 #ifdef CONFIG_SECURITY
1510 if (!fs_info->security_opts.num_mnt_opts) {
1511 /* first time security setup, copy sec_opts to fs_info */
1512 memcpy(&fs_info->security_opts, sec_opts, sizeof(*sec_opts));
1513 } else {
1514 /*
1515 * Since SELinux (the only one supporting security_mnt_opts)
1516 * does NOT support changing context during remount/mount of
1517 * the same sb, this must be the same or part of the same
1518 * security options, just free it.
1519 */
1520 security_free_mnt_opts(sec_opts);
1521 }
1522 #endif
1523 return ret;
1524 }
1525
1526 /*
1527 * Find a superblock for the given device / mount point.
1528 *
1529 * Note: This is based on get_sb_bdev from fs/super.c with a few additions
1530 * for multiple device setup. Make sure to keep it in sync.
1531 */
1532 static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
1533 const char *device_name, void *data)
1534 {
1535 struct block_device *bdev = NULL;
1536 struct super_block *s;
1537 struct btrfs_fs_devices *fs_devices = NULL;
1538 struct btrfs_fs_info *fs_info = NULL;
1539 struct security_mnt_opts new_sec_opts;
1540 fmode_t mode = FMODE_READ;
1541 char *subvol_name = NULL;
1542 u64 subvol_objectid = 0;
1543 int error = 0;
1544
1545 if (!(flags & MS_RDONLY))
1546 mode |= FMODE_WRITE;
1547
1548 error = btrfs_parse_early_options(data, mode, fs_type,
1549 &subvol_name, &subvol_objectid,
1550 &fs_devices);
1551 if (error) {
1552 kfree(subvol_name);
1553 return ERR_PTR(error);
1554 }
1555
1556 if (subvol_name || subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
1557 /* mount_subvol() will free subvol_name. */
1558 return mount_subvol(subvol_name, subvol_objectid, flags,
1559 device_name, data);
1560 }
1561
1562 security_init_mnt_opts(&new_sec_opts);
1563 if (data) {
1564 error = parse_security_options(data, &new_sec_opts);
1565 if (error)
1566 return ERR_PTR(error);
1567 }
1568
1569 error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices);
1570 if (error)
1571 goto error_sec_opts;
1572
1573 /*
1574 * Setup a dummy root and fs_info for test/set super. This is because
1575 * we don't actually fill this stuff out until open_ctree, but we need
1576 * it for searching for existing supers, so this lets us do that and
1577 * then open_ctree will properly initialize everything later.
1578 */
1579 fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_NOFS);
1580 if (!fs_info) {
1581 error = -ENOMEM;
1582 goto error_sec_opts;
1583 }
1584
1585 fs_info->fs_devices = fs_devices;
1586
1587 fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
1588 fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
1589 security_init_mnt_opts(&fs_info->security_opts);
1590 if (!fs_info->super_copy || !fs_info->super_for_commit) {
1591 error = -ENOMEM;
1592 goto error_fs_info;
1593 }
1594
1595 error = btrfs_open_devices(fs_devices, mode, fs_type);
1596 if (error)
1597 goto error_fs_info;
1598
1599 if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
1600 error = -EACCES;
1601 goto error_close_devices;
1602 }
1603
1604 bdev = fs_devices->latest_bdev;
1605 s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | MS_NOSEC,
1606 fs_info);
1607 if (IS_ERR(s)) {
1608 error = PTR_ERR(s);
1609 goto error_close_devices;
1610 }
1611
1612 if (s->s_root) {
1613 btrfs_close_devices(fs_devices);
1614 free_fs_info(fs_info);
1615 if ((flags ^ s->s_flags) & MS_RDONLY)
1616 error = -EBUSY;
1617 } else {
1618 snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev);
1619 btrfs_sb(s)->bdev_holder = fs_type;
1620 error = btrfs_fill_super(s, fs_devices, data,
1621 flags & MS_SILENT ? 1 : 0);
1622 }
1623 if (error) {
1624 deactivate_locked_super(s);
1625 goto error_sec_opts;
1626 }
1627
1628 fs_info = btrfs_sb(s);
1629 error = setup_security_options(fs_info, s, &new_sec_opts);
1630 if (error) {
1631 deactivate_locked_super(s);
1632 goto error_sec_opts;
1633 }
1634
1635 return dget(s->s_root);
1636
1637 error_close_devices:
1638 btrfs_close_devices(fs_devices);
1639 error_fs_info:
1640 free_fs_info(fs_info);
1641 error_sec_opts:
1642 security_free_mnt_opts(&new_sec_opts);
1643 return ERR_PTR(error);
1644 }
1645
1646 static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
1647 int new_pool_size, int old_pool_size)
1648 {
1649 if (new_pool_size == old_pool_size)
1650 return;
1651
1652 fs_info->thread_pool_size = new_pool_size;
1653
1654 btrfs_info(fs_info, "resize thread pool %d -> %d",
1655 old_pool_size, new_pool_size);
1656
1657 btrfs_workqueue_set_max(fs_info->workers, new_pool_size);
1658 btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size);
1659 btrfs_workqueue_set_max(fs_info->submit_workers, new_pool_size);
1660 btrfs_workqueue_set_max(fs_info->caching_workers, new_pool_size);
1661 btrfs_workqueue_set_max(fs_info->endio_workers, new_pool_size);
1662 btrfs_workqueue_set_max(fs_info->endio_meta_workers, new_pool_size);
1663 btrfs_workqueue_set_max(fs_info->endio_meta_write_workers,
1664 new_pool_size);
1665 btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size);
1666 btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
1667 btrfs_workqueue_set_max(fs_info->delayed_workers, new_pool_size);
1668 btrfs_workqueue_set_max(fs_info->readahead_workers, new_pool_size);
1669 btrfs_workqueue_set_max(fs_info->scrub_wr_completion_workers,
1670 new_pool_size);
1671 }
1672
1673 static inline void btrfs_remount_prepare(struct btrfs_fs_info *fs_info)
1674 {
1675 set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1676 }
1677
1678 static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info,
1679 unsigned long old_opts, int flags)
1680 {
1681 if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1682 (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1683 (flags & MS_RDONLY))) {
1684 /* wait for any defraggers to finish */
1685 wait_event(fs_info->transaction_wait,
1686 (atomic_read(&fs_info->defrag_running) == 0));
1687 if (flags & MS_RDONLY)
1688 sync_filesystem(fs_info->sb);
1689 }
1690 }
1691
1692 static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
1693 unsigned long old_opts)
1694 {
1695 /*
1696 * We need to cleanup all defragable inodes if the autodefragment is
1697 * close or the filesystem is read only.
1698 */
1699 if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1700 (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1701 (fs_info->sb->s_flags & MS_RDONLY))) {
1702 btrfs_cleanup_defrag_inodes(fs_info);
1703 }
1704
1705 clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1706 }
1707
1708 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
1709 {
1710 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1711 struct btrfs_root *root = fs_info->tree_root;
1712 unsigned old_flags = sb->s_flags;
1713 unsigned long old_opts = fs_info->mount_opt;
1714 unsigned long old_compress_type = fs_info->compress_type;
1715 u64 old_max_inline = fs_info->max_inline;
1716 u64 old_alloc_start = fs_info->alloc_start;
1717 int old_thread_pool_size = fs_info->thread_pool_size;
1718 unsigned int old_metadata_ratio = fs_info->metadata_ratio;
1719 int ret;
1720
1721 sync_filesystem(sb);
1722 btrfs_remount_prepare(fs_info);
1723
1724 if (data) {
1725 struct security_mnt_opts new_sec_opts;
1726
1727 security_init_mnt_opts(&new_sec_opts);
1728 ret = parse_security_options(data, &new_sec_opts);
1729 if (ret)
1730 goto restore;
1731 ret = setup_security_options(fs_info, sb,
1732 &new_sec_opts);
1733 if (ret) {
1734 security_free_mnt_opts(&new_sec_opts);
1735 goto restore;
1736 }
1737 }
1738
1739 ret = btrfs_parse_options(root, data, *flags);
1740 if (ret) {
1741 ret = -EINVAL;
1742 goto restore;
1743 }
1744
1745 btrfs_remount_begin(fs_info, old_opts, *flags);
1746 btrfs_resize_thread_pool(fs_info,
1747 fs_info->thread_pool_size, old_thread_pool_size);
1748
1749 if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1750 goto out;
1751
1752 if (*flags & MS_RDONLY) {
1753 /*
1754 * this also happens on 'umount -rf' or on shutdown, when
1755 * the filesystem is busy.
1756 */
1757 cancel_work_sync(&fs_info->async_reclaim_work);
1758
1759 /* wait for the uuid_scan task to finish */
1760 down(&fs_info->uuid_tree_rescan_sem);
1761 /* avoid complains from lockdep et al. */
1762 up(&fs_info->uuid_tree_rescan_sem);
1763
1764 sb->s_flags |= MS_RDONLY;
1765
1766 /*
1767 * Setting MS_RDONLY will put the cleaner thread to
1768 * sleep at the next loop if it's already active.
1769 * If it's already asleep, we'll leave unused block
1770 * groups on disk until we're mounted read-write again
1771 * unless we clean them up here.
1772 */
1773 btrfs_delete_unused_bgs(fs_info);
1774
1775 btrfs_dev_replace_suspend_for_unmount(fs_info);
1776 btrfs_scrub_cancel(fs_info);
1777 btrfs_pause_balance(fs_info);
1778
1779 ret = btrfs_commit_super(root);
1780 if (ret)
1781 goto restore;
1782 } else {
1783 if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state)) {
1784 btrfs_err(fs_info,
1785 "Remounting read-write after error is not allowed");
1786 ret = -EINVAL;
1787 goto restore;
1788 }
1789 if (fs_info->fs_devices->rw_devices == 0) {
1790 ret = -EACCES;
1791 goto restore;
1792 }
1793
1794 if (fs_info->fs_devices->missing_devices >
1795 fs_info->num_tolerated_disk_barrier_failures &&
1796 !(*flags & MS_RDONLY)) {
1797 btrfs_warn(fs_info,
1798 "too many missing devices, writeable remount is not allowed");
1799 ret = -EACCES;
1800 goto restore;
1801 }
1802
1803 if (btrfs_super_log_root(fs_info->super_copy) != 0) {
1804 ret = -EINVAL;
1805 goto restore;
1806 }
1807
1808 ret = btrfs_cleanup_fs_roots(fs_info);
1809 if (ret)
1810 goto restore;
1811
1812 /* recover relocation */
1813 mutex_lock(&fs_info->cleaner_mutex);
1814 ret = btrfs_recover_relocation(root);
1815 mutex_unlock(&fs_info->cleaner_mutex);
1816 if (ret)
1817 goto restore;
1818
1819 ret = btrfs_resume_balance_async(fs_info);
1820 if (ret)
1821 goto restore;
1822
1823 ret = btrfs_resume_dev_replace_async(fs_info);
1824 if (ret) {
1825 btrfs_warn(fs_info, "failed to resume dev_replace");
1826 goto restore;
1827 }
1828
1829 if (!fs_info->uuid_root) {
1830 btrfs_info(fs_info, "creating UUID tree");
1831 ret = btrfs_create_uuid_tree(fs_info);
1832 if (ret) {
1833 btrfs_warn(fs_info, "failed to create the UUID tree %d", ret);
1834 goto restore;
1835 }
1836 }
1837 sb->s_flags &= ~MS_RDONLY;
1838
1839 set_bit(BTRFS_FS_OPEN, &fs_info->flags);
1840 }
1841 out:
1842 wake_up_process(fs_info->transaction_kthread);
1843 btrfs_remount_cleanup(fs_info, old_opts);
1844 return 0;
1845
1846 restore:
1847 /* We've hit an error - don't reset MS_RDONLY */
1848 if (sb->s_flags & MS_RDONLY)
1849 old_flags |= MS_RDONLY;
1850 sb->s_flags = old_flags;
1851 fs_info->mount_opt = old_opts;
1852 fs_info->compress_type = old_compress_type;
1853 fs_info->max_inline = old_max_inline;
1854 mutex_lock(&fs_info->chunk_mutex);
1855 fs_info->alloc_start = old_alloc_start;
1856 mutex_unlock(&fs_info->chunk_mutex);
1857 btrfs_resize_thread_pool(fs_info,
1858 old_thread_pool_size, fs_info->thread_pool_size);
1859 fs_info->metadata_ratio = old_metadata_ratio;
1860 btrfs_remount_cleanup(fs_info, old_opts);
1861 return ret;
1862 }
1863
1864 /* Used to sort the devices by max_avail(descending sort) */
1865 static int btrfs_cmp_device_free_bytes(const void *dev_info1,
1866 const void *dev_info2)
1867 {
1868 if (((struct btrfs_device_info *)dev_info1)->max_avail >
1869 ((struct btrfs_device_info *)dev_info2)->max_avail)
1870 return -1;
1871 else if (((struct btrfs_device_info *)dev_info1)->max_avail <
1872 ((struct btrfs_device_info *)dev_info2)->max_avail)
1873 return 1;
1874 else
1875 return 0;
1876 }
1877
1878 /*
1879 * sort the devices by max_avail, in which max free extent size of each device
1880 * is stored.(Descending Sort)
1881 */
1882 static inline void btrfs_descending_sort_devices(
1883 struct btrfs_device_info *devices,
1884 size_t nr_devices)
1885 {
1886 sort(devices, nr_devices, sizeof(struct btrfs_device_info),
1887 btrfs_cmp_device_free_bytes, NULL);
1888 }
1889
1890 /*
1891 * The helper to calc the free space on the devices that can be used to store
1892 * file data.
1893 */
1894 static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes)
1895 {
1896 struct btrfs_fs_info *fs_info = root->fs_info;
1897 struct btrfs_device_info *devices_info;
1898 struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
1899 struct btrfs_device *device;
1900 u64 skip_space;
1901 u64 type;
1902 u64 avail_space;
1903 u64 used_space;
1904 u64 min_stripe_size;
1905 int min_stripes = 1, num_stripes = 1;
1906 int i = 0, nr_devices;
1907 int ret;
1908
1909 /*
1910 * We aren't under the device list lock, so this is racy-ish, but good
1911 * enough for our purposes.
1912 */
1913 nr_devices = fs_info->fs_devices->open_devices;
1914 if (!nr_devices) {
1915 smp_mb();
1916 nr_devices = fs_info->fs_devices->open_devices;
1917 ASSERT(nr_devices);
1918 if (!nr_devices) {
1919 *free_bytes = 0;
1920 return 0;
1921 }
1922 }
1923
1924 devices_info = kmalloc_array(nr_devices, sizeof(*devices_info),
1925 GFP_NOFS);
1926 if (!devices_info)
1927 return -ENOMEM;
1928
1929 /* calc min stripe number for data space allocation */
1930 type = btrfs_get_alloc_profile(root, 1);
1931 if (type & BTRFS_BLOCK_GROUP_RAID0) {
1932 min_stripes = 2;
1933 num_stripes = nr_devices;
1934 } else if (type & BTRFS_BLOCK_GROUP_RAID1) {
1935 min_stripes = 2;
1936 num_stripes = 2;
1937 } else if (type & BTRFS_BLOCK_GROUP_RAID10) {
1938 min_stripes = 4;
1939 num_stripes = 4;
1940 }
1941
1942 if (type & BTRFS_BLOCK_GROUP_DUP)
1943 min_stripe_size = 2 * BTRFS_STRIPE_LEN;
1944 else
1945 min_stripe_size = BTRFS_STRIPE_LEN;
1946
1947 if (fs_info->alloc_start)
1948 mutex_lock(&fs_devices->device_list_mutex);
1949 rcu_read_lock();
1950 list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
1951 if (!device->in_fs_metadata || !device->bdev ||
1952 device->is_tgtdev_for_dev_replace)
1953 continue;
1954
1955 if (i >= nr_devices)
1956 break;
1957
1958 avail_space = device->total_bytes - device->bytes_used;
1959
1960 /* align with stripe_len */
1961 avail_space = div_u64(avail_space, BTRFS_STRIPE_LEN);
1962 avail_space *= BTRFS_STRIPE_LEN;
1963
1964 /*
1965 * In order to avoid overwriting the superblock on the drive,
1966 * btrfs starts at an offset of at least 1MB when doing chunk
1967 * allocation.
1968 */
1969 skip_space = SZ_1M;
1970
1971 /* user can set the offset in fs_info->alloc_start. */
1972 if (fs_info->alloc_start &&
1973 fs_info->alloc_start + BTRFS_STRIPE_LEN <=
1974 device->total_bytes) {
1975 rcu_read_unlock();
1976 skip_space = max(fs_info->alloc_start, skip_space);
1977
1978 /*
1979 * btrfs can not use the free space in
1980 * [0, skip_space - 1], we must subtract it from the
1981 * total. In order to implement it, we account the used
1982 * space in this range first.
1983 */
1984 ret = btrfs_account_dev_extents_size(device, 0,
1985 skip_space - 1,
1986 &used_space);
1987 if (ret) {
1988 kfree(devices_info);
1989 mutex_unlock(&fs_devices->device_list_mutex);
1990 return ret;
1991 }
1992
1993 rcu_read_lock();
1994
1995 /* calc the free space in [0, skip_space - 1] */
1996 skip_space -= used_space;
1997 }
1998
1999 /*
2000 * we can use the free space in [0, skip_space - 1], subtract
2001 * it from the total.
2002 */
2003 if (avail_space && avail_space >= skip_space)
2004 avail_space -= skip_space;
2005 else
2006 avail_space = 0;
2007
2008 if (avail_space < min_stripe_size)
2009 continue;
2010
2011 devices_info[i].dev = device;
2012 devices_info[i].max_avail = avail_space;
2013
2014 i++;
2015 }
2016 rcu_read_unlock();
2017 if (fs_info->alloc_start)
2018 mutex_unlock(&fs_devices->device_list_mutex);
2019
2020 nr_devices = i;
2021
2022 btrfs_descending_sort_devices(devices_info, nr_devices);
2023
2024 i = nr_devices - 1;
2025 avail_space = 0;
2026 while (nr_devices >= min_stripes) {
2027 if (num_stripes > nr_devices)
2028 num_stripes = nr_devices;
2029
2030 if (devices_info[i].max_avail >= min_stripe_size) {
2031 int j;
2032 u64 alloc_size;
2033
2034 avail_space += devices_info[i].max_avail * num_stripes;
2035 alloc_size = devices_info[i].max_avail;
2036 for (j = i + 1 - num_stripes; j <= i; j++)
2037 devices_info[j].max_avail -= alloc_size;
2038 }
2039 i--;
2040 nr_devices--;
2041 }
2042
2043 kfree(devices_info);
2044 *free_bytes = avail_space;
2045 return 0;
2046 }
2047
2048 /*
2049 * Calculate numbers for 'df', pessimistic in case of mixed raid profiles.
2050 *
2051 * If there's a redundant raid level at DATA block groups, use the respective
2052 * multiplier to scale the sizes.
2053 *
2054 * Unused device space usage is based on simulating the chunk allocator
2055 * algorithm that respects the device sizes, order of allocations and the
2056 * 'alloc_start' value, this is a close approximation of the actual use but
2057 * there are other factors that may change the result (like a new metadata
2058 * chunk).
2059 *
2060 * If metadata is exhausted, f_bavail will be 0.
2061 */
2062 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
2063 {
2064 struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
2065 struct btrfs_super_block *disk_super = fs_info->super_copy;
2066 struct list_head *head = &fs_info->space_info;
2067 struct btrfs_space_info *found;
2068 u64 total_used = 0;
2069 u64 total_free_data = 0;
2070 u64 total_free_meta = 0;
2071 int bits = dentry->d_sb->s_blocksize_bits;
2072 __be32 *fsid = (__be32 *)fs_info->fsid;
2073 unsigned factor = 1;
2074 struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
2075 int ret;
2076 u64 thresh = 0;
2077 int mixed = 0;
2078
2079 /*
2080 * holding chunk_mutex to avoid allocating new chunks, holding
2081 * device_list_mutex to avoid the device being removed
2082 */
2083 rcu_read_lock();
2084 list_for_each_entry_rcu(found, head, list) {
2085 if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
2086 int i;
2087
2088 total_free_data += found->disk_total - found->disk_used;
2089 total_free_data -=
2090 btrfs_account_ro_block_groups_free_space(found);
2091
2092 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
2093 if (!list_empty(&found->block_groups[i])) {
2094 switch (i) {
2095 case BTRFS_RAID_DUP:
2096 case BTRFS_RAID_RAID1:
2097 case BTRFS_RAID_RAID10:
2098 factor = 2;
2099 }
2100 }
2101 }
2102 }
2103
2104 /*
2105 * Metadata in mixed block goup profiles are accounted in data
2106 */
2107 if (!mixed && found->flags & BTRFS_BLOCK_GROUP_METADATA) {
2108 if (found->flags & BTRFS_BLOCK_GROUP_DATA)
2109 mixed = 1;
2110 else
2111 total_free_meta += found->disk_total -
2112 found->disk_used;
2113 }
2114
2115 total_used += found->disk_used;
2116 }
2117
2118 rcu_read_unlock();
2119
2120 buf->f_blocks = div_u64(btrfs_super_total_bytes(disk_super), factor);
2121 buf->f_blocks >>= bits;
2122 buf->f_bfree = buf->f_blocks - (div_u64(total_used, factor) >> bits);
2123
2124 /* Account global block reserve as used, it's in logical size already */
2125 spin_lock(&block_rsv->lock);
2126 /* Mixed block groups accounting is not byte-accurate, avoid overflow */
2127 if (buf->f_bfree >= block_rsv->size >> bits)
2128 buf->f_bfree -= block_rsv->size >> bits;
2129 else
2130 buf->f_bfree = 0;
2131 spin_unlock(&block_rsv->lock);
2132
2133 buf->f_bavail = div_u64(total_free_data, factor);
2134 ret = btrfs_calc_avail_data_space(fs_info->tree_root, &total_free_data);
2135 if (ret)
2136 return ret;
2137 buf->f_bavail += div_u64(total_free_data, factor);
2138 buf->f_bavail = buf->f_bavail >> bits;
2139
2140 /*
2141 * We calculate the remaining metadata space minus global reserve. If
2142 * this is (supposedly) smaller than zero, there's no space. But this
2143 * does not hold in practice, the exhausted state happens where's still
2144 * some positive delta. So we apply some guesswork and compare the
2145 * delta to a 4M threshold. (Practically observed delta was ~2M.)
2146 *
2147 * We probably cannot calculate the exact threshold value because this
2148 * depends on the internal reservations requested by various
2149 * operations, so some operations that consume a few metadata will
2150 * succeed even if the Avail is zero. But this is better than the other
2151 * way around.
2152 */
2153 thresh = 4 * 1024 * 1024;
2154
2155 if (!mixed && total_free_meta - thresh < block_rsv->size)
2156 buf->f_bavail = 0;
2157
2158 buf->f_type = BTRFS_SUPER_MAGIC;
2159 buf->f_bsize = dentry->d_sb->s_blocksize;
2160 buf->f_namelen = BTRFS_NAME_LEN;
2161
2162 /* We treat it as constant endianness (it doesn't matter _which_)
2163 because we want the fsid to come out the same whether mounted
2164 on a big-endian or little-endian host */
2165 buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
2166 buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
2167 /* Mask in the root object ID too, to disambiguate subvols */
2168 buf->f_fsid.val[0] ^= BTRFS_I(d_inode(dentry))->root->objectid >> 32;
2169 buf->f_fsid.val[1] ^= BTRFS_I(d_inode(dentry))->root->objectid;
2170
2171 return 0;
2172 }
2173
2174 static void btrfs_kill_super(struct super_block *sb)
2175 {
2176 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2177 kill_anon_super(sb);
2178 free_fs_info(fs_info);
2179 }
2180
2181 static struct file_system_type btrfs_fs_type = {
2182 .owner = THIS_MODULE,
2183 .name = "btrfs",
2184 .mount = btrfs_mount,
2185 .kill_sb = btrfs_kill_super,
2186 .fs_flags = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,
2187 };
2188 MODULE_ALIAS_FS("btrfs");
2189
2190 static int btrfs_control_open(struct inode *inode, struct file *file)
2191 {
2192 /*
2193 * The control file's private_data is used to hold the
2194 * transaction when it is started and is used to keep
2195 * track of whether a transaction is already in progress.
2196 */
2197 file->private_data = NULL;
2198 return 0;
2199 }
2200
2201 /*
2202 * used by btrfsctl to scan devices when no FS is mounted
2203 */
2204 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
2205 unsigned long arg)
2206 {
2207 struct btrfs_ioctl_vol_args *vol;
2208 struct btrfs_fs_devices *fs_devices;
2209 int ret = -ENOTTY;
2210
2211 if (!capable(CAP_SYS_ADMIN))
2212 return -EPERM;
2213
2214 vol = memdup_user((void __user *)arg, sizeof(*vol));
2215 if (IS_ERR(vol))
2216 return PTR_ERR(vol);
2217
2218 switch (cmd) {
2219 case BTRFS_IOC_SCAN_DEV:
2220 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
2221 &btrfs_fs_type, &fs_devices);
2222 break;
2223 case BTRFS_IOC_DEVICES_READY:
2224 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
2225 &btrfs_fs_type, &fs_devices);
2226 if (ret)
2227 break;
2228 ret = !(fs_devices->num_devices == fs_devices->total_devices);
2229 break;
2230 case BTRFS_IOC_GET_SUPPORTED_FEATURES:
2231 ret = btrfs_ioctl_get_supported_features((void __user*)arg);
2232 break;
2233 }
2234
2235 kfree(vol);
2236 return ret;
2237 }
2238
2239 static int btrfs_freeze(struct super_block *sb)
2240 {
2241 struct btrfs_trans_handle *trans;
2242 struct btrfs_root *root = btrfs_sb(sb)->tree_root;
2243
2244 root->fs_info->fs_frozen = 1;
2245 /*
2246 * We don't need a barrier here, we'll wait for any transaction that
2247 * could be in progress on other threads (and do delayed iputs that
2248 * we want to avoid on a frozen filesystem), or do the commit
2249 * ourselves.
2250 */
2251 trans = btrfs_attach_transaction_barrier(root);
2252 if (IS_ERR(trans)) {
2253 /* no transaction, don't bother */
2254 if (PTR_ERR(trans) == -ENOENT)
2255 return 0;
2256 return PTR_ERR(trans);
2257 }
2258 return btrfs_commit_transaction(trans, root);
2259 }
2260
2261 static int btrfs_unfreeze(struct super_block *sb)
2262 {
2263 struct btrfs_root *root = btrfs_sb(sb)->tree_root;
2264
2265 root->fs_info->fs_frozen = 0;
2266 return 0;
2267 }
2268
2269 static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
2270 {
2271 struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
2272 struct btrfs_fs_devices *cur_devices;
2273 struct btrfs_device *dev, *first_dev = NULL;
2274 struct list_head *head;
2275 struct rcu_string *name;
2276
2277 mutex_lock(&fs_info->fs_devices->device_list_mutex);
2278 cur_devices = fs_info->fs_devices;
2279 while (cur_devices) {
2280 head = &cur_devices->devices;
2281 list_for_each_entry(dev, head, dev_list) {
2282 if (dev->missing)
2283 continue;
2284 if (!dev->name)
2285 continue;
2286 if (!first_dev || dev->devid < first_dev->devid)
2287 first_dev = dev;
2288 }
2289 cur_devices = cur_devices->seed;
2290 }
2291
2292 if (first_dev) {
2293 rcu_read_lock();
2294 name = rcu_dereference(first_dev->name);
2295 seq_escape(m, name->str, " \t\n\\");
2296 rcu_read_unlock();
2297 } else {
2298 WARN_ON(1);
2299 }
2300 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2301 return 0;
2302 }
2303
2304 static const struct super_operations btrfs_super_ops = {
2305 .drop_inode = btrfs_drop_inode,
2306 .evict_inode = btrfs_evict_inode,
2307 .put_super = btrfs_put_super,
2308 .sync_fs = btrfs_sync_fs,
2309 .show_options = btrfs_show_options,
2310 .show_devname = btrfs_show_devname,
2311 .write_inode = btrfs_write_inode,
2312 .alloc_inode = btrfs_alloc_inode,
2313 .destroy_inode = btrfs_destroy_inode,
2314 .statfs = btrfs_statfs,
2315 .remount_fs = btrfs_remount,
2316 .freeze_fs = btrfs_freeze,
2317 .unfreeze_fs = btrfs_unfreeze,
2318 };
2319
2320 static const struct file_operations btrfs_ctl_fops = {
2321 .open = btrfs_control_open,
2322 .unlocked_ioctl = btrfs_control_ioctl,
2323 .compat_ioctl = btrfs_control_ioctl,
2324 .owner = THIS_MODULE,
2325 .llseek = noop_llseek,
2326 };
2327
2328 static struct miscdevice btrfs_misc = {
2329 .minor = BTRFS_MINOR,
2330 .name = "btrfs-control",
2331 .fops = &btrfs_ctl_fops
2332 };
2333
2334 MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
2335 MODULE_ALIAS("devname:btrfs-control");
2336
2337 static int btrfs_interface_init(void)
2338 {
2339 return misc_register(&btrfs_misc);
2340 }
2341
2342 static void btrfs_interface_exit(void)
2343 {
2344 misc_deregister(&btrfs_misc);
2345 }
2346
2347 static void btrfs_print_mod_info(void)
2348 {
2349 printk(KERN_INFO "Btrfs loaded, crc32c=%s"
2350 #ifdef CONFIG_BTRFS_DEBUG
2351 ", debug=on"
2352 #endif
2353 #ifdef CONFIG_BTRFS_ASSERT
2354 ", assert=on"
2355 #endif
2356 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
2357 ", integrity-checker=on"
2358 #endif
2359 "\n",
2360 btrfs_crc32c_impl());
2361 }
2362
2363 static int __init init_btrfs_fs(void)
2364 {
2365 int err;
2366
2367 err = btrfs_hash_init();
2368 if (err)
2369 return err;
2370
2371 btrfs_props_init();
2372
2373 err = btrfs_init_sysfs();
2374 if (err)
2375 goto free_hash;
2376
2377 btrfs_init_compress();
2378
2379 err = btrfs_init_cachep();
2380 if (err)
2381 goto free_compress;
2382
2383 err = extent_io_init();
2384 if (err)
2385 goto free_cachep;
2386
2387 err = extent_map_init();
2388 if (err)
2389 goto free_extent_io;
2390
2391 err = ordered_data_init();
2392 if (err)
2393 goto free_extent_map;
2394
2395 err = btrfs_delayed_inode_init();
2396 if (err)
2397 goto free_ordered_data;
2398
2399 err = btrfs_auto_defrag_init();
2400 if (err)
2401 goto free_delayed_inode;
2402
2403 err = btrfs_delayed_ref_init();
2404 if (err)
2405 goto free_auto_defrag;
2406
2407 err = btrfs_prelim_ref_init();
2408 if (err)
2409 goto free_delayed_ref;
2410
2411 err = btrfs_end_io_wq_init();
2412 if (err)
2413 goto free_prelim_ref;
2414
2415 err = btrfs_interface_init();
2416 if (err)
2417 goto free_end_io_wq;
2418
2419 btrfs_init_lockdep();
2420
2421 btrfs_print_mod_info();
2422
2423 err = btrfs_run_sanity_tests();
2424 if (err)
2425 goto unregister_ioctl;
2426
2427 err = register_filesystem(&btrfs_fs_type);
2428 if (err)
2429 goto unregister_ioctl;
2430
2431 return 0;
2432
2433 unregister_ioctl:
2434 btrfs_interface_exit();
2435 free_end_io_wq:
2436 btrfs_end_io_wq_exit();
2437 free_prelim_ref:
2438 btrfs_prelim_ref_exit();
2439 free_delayed_ref:
2440 btrfs_delayed_ref_exit();
2441 free_auto_defrag:
2442 btrfs_auto_defrag_exit();
2443 free_delayed_inode:
2444 btrfs_delayed_inode_exit();
2445 free_ordered_data:
2446 ordered_data_exit();
2447 free_extent_map:
2448 extent_map_exit();
2449 free_extent_io:
2450 extent_io_exit();
2451 free_cachep:
2452 btrfs_destroy_cachep();
2453 free_compress:
2454 btrfs_exit_compress();
2455 btrfs_exit_sysfs();
2456 free_hash:
2457 btrfs_hash_exit();
2458 return err;
2459 }
2460
2461 static void __exit exit_btrfs_fs(void)
2462 {
2463 btrfs_destroy_cachep();
2464 btrfs_delayed_ref_exit();
2465 btrfs_auto_defrag_exit();
2466 btrfs_delayed_inode_exit();
2467 btrfs_prelim_ref_exit();
2468 ordered_data_exit();
2469 extent_map_exit();
2470 extent_io_exit();
2471 btrfs_interface_exit();
2472 btrfs_end_io_wq_exit();
2473 unregister_filesystem(&btrfs_fs_type);
2474 btrfs_exit_sysfs();
2475 btrfs_cleanup_fs_uuids();
2476 btrfs_exit_compress();
2477 btrfs_hash_exit();
2478 }
2479
2480 late_initcall(init_btrfs_fs);
2481 module_exit(exit_btrfs_fs)
2482
2483 MODULE_LICENSE("GPL");
Linux kernel - Deliverables
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