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Btrfs: fix output of compression message in btrfs_parse_options()
[deliverable/linux.git] / fs / btrfs / super.c
1 /*
2 * Copyright (C) 2007 Oracle. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18
19 #include <linux/blkdev.h>
20 #include <linux/module.h>
21 #include <linux/buffer_head.h>
22 #include <linux/fs.h>
23 #include <linux/pagemap.h>
24 #include <linux/highmem.h>
25 #include <linux/time.h>
26 #include <linux/init.h>
27 #include <linux/seq_file.h>
28 #include <linux/string.h>
29 #include <linux/backing-dev.h>
30 #include <linux/mount.h>
31 #include <linux/mpage.h>
32 #include <linux/swap.h>
33 #include <linux/writeback.h>
34 #include <linux/statfs.h>
35 #include <linux/compat.h>
36 #include <linux/parser.h>
37 #include <linux/ctype.h>
38 #include <linux/namei.h>
39 #include <linux/miscdevice.h>
40 #include <linux/magic.h>
41 #include <linux/slab.h>
42 #include <linux/cleancache.h>
43 #include <linux/ratelimit.h>
44 #include <linux/btrfs.h>
45 #include "delayed-inode.h"
46 #include "ctree.h"
47 #include "disk-io.h"
48 #include "transaction.h"
49 #include "btrfs_inode.h"
50 #include "print-tree.h"
51 #include "hash.h"
52 #include "props.h"
53 #include "xattr.h"
54 #include "volumes.h"
55 #include "export.h"
56 #include "compression.h"
57 #include "rcu-string.h"
58 #include "dev-replace.h"
59 #include "free-space-cache.h"
60 #include "backref.h"
61 #include "tests/btrfs-tests.h"
62
63 #include "qgroup.h"
64 #define CREATE_TRACE_POINTS
65 #include <trace/events/btrfs.h>
66
67 static const struct super_operations btrfs_super_ops;
68 static struct file_system_type btrfs_fs_type;
69
70 static int btrfs_remount(struct super_block *sb, int *flags, char *data);
71
72 const char *btrfs_decode_error(int errno)
73 {
74 char *errstr = "unknown";
75
76 switch (errno) {
77 case -EIO:
78 errstr = "IO failure";
79 break;
80 case -ENOMEM:
81 errstr = "Out of memory";
82 break;
83 case -EROFS:
84 errstr = "Readonly filesystem";
85 break;
86 case -EEXIST:
87 errstr = "Object already exists";
88 break;
89 case -ENOSPC:
90 errstr = "No space left";
91 break;
92 case -ENOENT:
93 errstr = "No such entry";
94 break;
95 }
96
97 return errstr;
98 }
99
100 static void save_error_info(struct btrfs_fs_info *fs_info)
101 {
102 /*
103 * today we only save the error info into ram. Long term we'll
104 * also send it down to the disk
105 */
106 set_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state);
107 }
108
109 /* btrfs handle error by forcing the filesystem readonly */
110 static void btrfs_handle_error(struct btrfs_fs_info *fs_info)
111 {
112 struct super_block *sb = fs_info->sb;
113
114 if (sb->s_flags & MS_RDONLY)
115 return;
116
117 if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
118 sb->s_flags |= MS_RDONLY;
119 btrfs_info(fs_info, "forced readonly");
120 /*
121 * Note that a running device replace operation is not
122 * canceled here although there is no way to update
123 * the progress. It would add the risk of a deadlock,
124 * therefore the canceling is ommited. The only penalty
125 * is that some I/O remains active until the procedure
126 * completes. The next time when the filesystem is
127 * mounted writeable again, the device replace
128 * operation continues.
129 */
130 }
131 }
132
133 /*
134 * __btrfs_std_error decodes expected errors from the caller and
135 * invokes the approciate error response.
136 */
137 __cold
138 void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function,
139 unsigned int line, int errno, const char *fmt, ...)
140 {
141 struct super_block *sb = fs_info->sb;
142 #ifdef CONFIG_PRINTK
143 const char *errstr;
144 #endif
145
146 /*
147 * Special case: if the error is EROFS, and we're already
148 * under MS_RDONLY, then it is safe here.
149 */
150 if (errno == -EROFS && (sb->s_flags & MS_RDONLY))
151 return;
152
153 #ifdef CONFIG_PRINTK
154 errstr = btrfs_decode_error(errno);
155 if (fmt) {
156 struct va_format vaf;
157 va_list args;
158
159 va_start(args, fmt);
160 vaf.fmt = fmt;
161 vaf.va = &args;
162
163 printk(KERN_CRIT
164 "BTRFS: error (device %s) in %s:%d: errno=%d %s (%pV)\n",
165 sb->s_id, function, line, errno, errstr, &vaf);
166 va_end(args);
167 } else {
168 printk(KERN_CRIT "BTRFS: error (device %s) in %s:%d: errno=%d %s\n",
169 sb->s_id, function, line, errno, errstr);
170 }
171 #endif
172
173 /* Don't go through full error handling during mount */
174 save_error_info(fs_info);
175 if (sb->s_flags & MS_BORN)
176 btrfs_handle_error(fs_info);
177 }
178
179 #ifdef CONFIG_PRINTK
180 static const char * const logtypes[] = {
181 "emergency",
182 "alert",
183 "critical",
184 "error",
185 "warning",
186 "notice",
187 "info",
188 "debug",
189 };
190
191 void btrfs_printk(const struct btrfs_fs_info *fs_info, const char *fmt, ...)
192 {
193 struct super_block *sb = fs_info->sb;
194 char lvl[4];
195 struct va_format vaf;
196 va_list args;
197 const char *type = logtypes[4];
198 int kern_level;
199
200 va_start(args, fmt);
201
202 kern_level = printk_get_level(fmt);
203 if (kern_level) {
204 size_t size = printk_skip_level(fmt) - fmt;
205 memcpy(lvl, fmt, size);
206 lvl[size] = '\0';
207 fmt += size;
208 type = logtypes[kern_level - '0'];
209 } else
210 *lvl = '\0';
211
212 vaf.fmt = fmt;
213 vaf.va = &args;
214
215 printk("%sBTRFS %s (device %s): %pV\n", lvl, type, sb->s_id, &vaf);
216
217 va_end(args);
218 }
219 #endif
220
221 /*
222 * We only mark the transaction aborted and then set the file system read-only.
223 * This will prevent new transactions from starting or trying to join this
224 * one.
225 *
226 * This means that error recovery at the call site is limited to freeing
227 * any local memory allocations and passing the error code up without
228 * further cleanup. The transaction should complete as it normally would
229 * in the call path but will return -EIO.
230 *
231 * We'll complete the cleanup in btrfs_end_transaction and
232 * btrfs_commit_transaction.
233 */
234 __cold
235 void __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
236 struct btrfs_root *root, const char *function,
237 unsigned int line, int errno)
238 {
239 trans->aborted = errno;
240 /* Nothing used. The other threads that have joined this
241 * transaction may be able to continue. */
242 if (!trans->blocks_used && list_empty(&trans->new_bgs)) {
243 const char *errstr;
244
245 errstr = btrfs_decode_error(errno);
246 btrfs_warn(root->fs_info,
247 "%s:%d: Aborting unused transaction(%s).",
248 function, line, errstr);
249 return;
250 }
251 ACCESS_ONCE(trans->transaction->aborted) = errno;
252 /* Wake up anybody who may be waiting on this transaction */
253 wake_up(&root->fs_info->transaction_wait);
254 wake_up(&root->fs_info->transaction_blocked_wait);
255 __btrfs_std_error(root->fs_info, function, line, errno, NULL);
256 }
257 /*
258 * __btrfs_panic decodes unexpected, fatal errors from the caller,
259 * issues an alert, and either panics or BUGs, depending on mount options.
260 */
261 __cold
262 void __btrfs_panic(struct btrfs_fs_info *fs_info, const char *function,
263 unsigned int line, int errno, const char *fmt, ...)
264 {
265 char *s_id = "<unknown>";
266 const char *errstr;
267 struct va_format vaf = { .fmt = fmt };
268 va_list args;
269
270 if (fs_info)
271 s_id = fs_info->sb->s_id;
272
273 va_start(args, fmt);
274 vaf.va = &args;
275
276 errstr = btrfs_decode_error(errno);
277 if (fs_info && (fs_info->mount_opt & BTRFS_MOUNT_PANIC_ON_FATAL_ERROR))
278 panic(KERN_CRIT "BTRFS panic (device %s) in %s:%d: %pV (errno=%d %s)\n",
279 s_id, function, line, &vaf, errno, errstr);
280
281 btrfs_crit(fs_info, "panic in %s:%d: %pV (errno=%d %s)",
282 function, line, &vaf, errno, errstr);
283 va_end(args);
284 /* Caller calls BUG() */
285 }
286
287 static void btrfs_put_super(struct super_block *sb)
288 {
289 close_ctree(btrfs_sb(sb)->tree_root);
290 }
291
292 enum {
293 Opt_degraded, Opt_subvol, Opt_subvolid, Opt_device, Opt_nodatasum,
294 Opt_nodatacow, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd,
295 Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl, Opt_compress,
296 Opt_compress_type, Opt_compress_force, Opt_compress_force_type,
297 Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard,
298 Opt_space_cache, Opt_clear_cache, Opt_user_subvol_rm_allowed,
299 Opt_enospc_debug, Opt_subvolrootid, Opt_defrag, Opt_inode_cache,
300 Opt_no_space_cache, Opt_recovery, Opt_skip_balance,
301 Opt_check_integrity, Opt_check_integrity_including_extent_data,
302 Opt_check_integrity_print_mask, Opt_fatal_errors, Opt_rescan_uuid_tree,
303 Opt_commit_interval, Opt_barrier, Opt_nodefrag, Opt_nodiscard,
304 Opt_noenospc_debug, Opt_noflushoncommit, Opt_acl, Opt_datacow,
305 Opt_datasum, Opt_treelog, Opt_noinode_cache,
306 #ifdef CONFIG_BTRFS_DEBUG
307 Opt_fragment_data, Opt_fragment_metadata, Opt_fragment_all,
308 #endif
309 Opt_err,
310 };
311
312 static const match_table_t tokens = {
313 {Opt_degraded, "degraded"},
314 {Opt_subvol, "subvol=%s"},
315 {Opt_subvolid, "subvolid=%s"},
316 {Opt_device, "device=%s"},
317 {Opt_nodatasum, "nodatasum"},
318 {Opt_datasum, "datasum"},
319 {Opt_nodatacow, "nodatacow"},
320 {Opt_datacow, "datacow"},
321 {Opt_nobarrier, "nobarrier"},
322 {Opt_barrier, "barrier"},
323 {Opt_max_inline, "max_inline=%s"},
324 {Opt_alloc_start, "alloc_start=%s"},
325 {Opt_thread_pool, "thread_pool=%d"},
326 {Opt_compress, "compress"},
327 {Opt_compress_type, "compress=%s"},
328 {Opt_compress_force, "compress-force"},
329 {Opt_compress_force_type, "compress-force=%s"},
330 {Opt_ssd, "ssd"},
331 {Opt_ssd_spread, "ssd_spread"},
332 {Opt_nossd, "nossd"},
333 {Opt_acl, "acl"},
334 {Opt_noacl, "noacl"},
335 {Opt_notreelog, "notreelog"},
336 {Opt_treelog, "treelog"},
337 {Opt_flushoncommit, "flushoncommit"},
338 {Opt_noflushoncommit, "noflushoncommit"},
339 {Opt_ratio, "metadata_ratio=%d"},
340 {Opt_discard, "discard"},
341 {Opt_nodiscard, "nodiscard"},
342 {Opt_space_cache, "space_cache"},
343 {Opt_clear_cache, "clear_cache"},
344 {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
345 {Opt_enospc_debug, "enospc_debug"},
346 {Opt_noenospc_debug, "noenospc_debug"},
347 {Opt_subvolrootid, "subvolrootid=%d"},
348 {Opt_defrag, "autodefrag"},
349 {Opt_nodefrag, "noautodefrag"},
350 {Opt_inode_cache, "inode_cache"},
351 {Opt_noinode_cache, "noinode_cache"},
352 {Opt_no_space_cache, "nospace_cache"},
353 {Opt_recovery, "recovery"},
354 {Opt_skip_balance, "skip_balance"},
355 {Opt_check_integrity, "check_int"},
356 {Opt_check_integrity_including_extent_data, "check_int_data"},
357 {Opt_check_integrity_print_mask, "check_int_print_mask=%d"},
358 {Opt_rescan_uuid_tree, "rescan_uuid_tree"},
359 {Opt_fatal_errors, "fatal_errors=%s"},
360 {Opt_commit_interval, "commit=%d"},
361 #ifdef CONFIG_BTRFS_DEBUG
362 {Opt_fragment_data, "fragment=data"},
363 {Opt_fragment_metadata, "fragment=metadata"},
364 {Opt_fragment_all, "fragment=all"},
365 #endif
366 {Opt_err, NULL},
367 };
368
369 /*
370 * Regular mount options parser. Everything that is needed only when
371 * reading in a new superblock is parsed here.
372 * XXX JDM: This needs to be cleaned up for remount.
373 */
374 int btrfs_parse_options(struct btrfs_root *root, char *options)
375 {
376 struct btrfs_fs_info *info = root->fs_info;
377 substring_t args[MAX_OPT_ARGS];
378 char *p, *num, *orig = NULL;
379 u64 cache_gen;
380 int intarg;
381 int ret = 0;
382 char *compress_type;
383 bool compress_force = false;
384 enum btrfs_compression_type saved_compress_type;
385 bool saved_compress_force;
386 int no_compress = 0;
387
388 cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
389 if (cache_gen)
390 btrfs_set_opt(info->mount_opt, SPACE_CACHE);
391
392 if (!options)
393 goto out;
394
395 /*
396 * strsep changes the string, duplicate it because parse_options
397 * gets called twice
398 */
399 options = kstrdup(options, GFP_NOFS);
400 if (!options)
401 return -ENOMEM;
402
403 orig = options;
404
405 while ((p = strsep(&options, ",")) != NULL) {
406 int token;
407 if (!*p)
408 continue;
409
410 token = match_token(p, tokens, args);
411 switch (token) {
412 case Opt_degraded:
413 btrfs_info(root->fs_info, "allowing degraded mounts");
414 btrfs_set_opt(info->mount_opt, DEGRADED);
415 break;
416 case Opt_subvol:
417 case Opt_subvolid:
418 case Opt_subvolrootid:
419 case Opt_device:
420 /*
421 * These are parsed by btrfs_parse_early_options
422 * and can be happily ignored here.
423 */
424 break;
425 case Opt_nodatasum:
426 btrfs_set_and_info(root, NODATASUM,
427 "setting nodatasum");
428 break;
429 case Opt_datasum:
430 if (btrfs_test_opt(root, NODATASUM)) {
431 if (btrfs_test_opt(root, NODATACOW))
432 btrfs_info(root->fs_info, "setting datasum, datacow enabled");
433 else
434 btrfs_info(root->fs_info, "setting datasum");
435 }
436 btrfs_clear_opt(info->mount_opt, NODATACOW);
437 btrfs_clear_opt(info->mount_opt, NODATASUM);
438 break;
439 case Opt_nodatacow:
440 if (!btrfs_test_opt(root, NODATACOW)) {
441 if (!btrfs_test_opt(root, COMPRESS) ||
442 !btrfs_test_opt(root, FORCE_COMPRESS)) {
443 btrfs_info(root->fs_info,
444 "setting nodatacow, compression disabled");
445 } else {
446 btrfs_info(root->fs_info, "setting nodatacow");
447 }
448 }
449 btrfs_clear_opt(info->mount_opt, COMPRESS);
450 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
451 btrfs_set_opt(info->mount_opt, NODATACOW);
452 btrfs_set_opt(info->mount_opt, NODATASUM);
453 break;
454 case Opt_datacow:
455 btrfs_clear_and_info(root, NODATACOW,
456 "setting datacow");
457 break;
458 case Opt_compress_force:
459 case Opt_compress_force_type:
460 compress_force = true;
461 /* Fallthrough */
462 case Opt_compress:
463 case Opt_compress_type:
464 saved_compress_type = btrfs_test_opt(root, COMPRESS) ?
465 info->compress_type : BTRFS_COMPRESS_NONE;
466 saved_compress_force =
467 btrfs_test_opt(root, FORCE_COMPRESS);
468 if (token == Opt_compress ||
469 token == Opt_compress_force ||
470 strcmp(args[0].from, "zlib") == 0) {
471 compress_type = "zlib";
472 info->compress_type = BTRFS_COMPRESS_ZLIB;
473 btrfs_set_opt(info->mount_opt, COMPRESS);
474 btrfs_clear_opt(info->mount_opt, NODATACOW);
475 btrfs_clear_opt(info->mount_opt, NODATASUM);
476 no_compress = 0;
477 } else if (strcmp(args[0].from, "lzo") == 0) {
478 compress_type = "lzo";
479 info->compress_type = BTRFS_COMPRESS_LZO;
480 btrfs_set_opt(info->mount_opt, COMPRESS);
481 btrfs_clear_opt(info->mount_opt, NODATACOW);
482 btrfs_clear_opt(info->mount_opt, NODATASUM);
483 btrfs_set_fs_incompat(info, COMPRESS_LZO);
484 no_compress = 0;
485 } else if (strncmp(args[0].from, "no", 2) == 0) {
486 compress_type = "no";
487 btrfs_clear_opt(info->mount_opt, COMPRESS);
488 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
489 compress_force = false;
490 no_compress++;
491 } else {
492 ret = -EINVAL;
493 goto out;
494 }
495
496 if (compress_force) {
497 btrfs_set_opt(info->mount_opt, FORCE_COMPRESS);
498 } else {
499 /*
500 * If we remount from compress-force=xxx to
501 * compress=xxx, we need clear FORCE_COMPRESS
502 * flag, otherwise, there is no way for users
503 * to disable forcible compression separately.
504 */
505 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
506 }
507 if ((btrfs_test_opt(root, COMPRESS) &&
508 (info->compress_type != saved_compress_type ||
509 compress_force != saved_compress_force)) ||
510 (!btrfs_test_opt(root, COMPRESS) &&
511 no_compress == 1)) {
512 btrfs_info(root->fs_info,
513 "%s %s compression",
514 (compress_force) ? "force" : "use",
515 compress_type);
516 }
517 compress_force = false;
518 break;
519 case Opt_ssd:
520 btrfs_set_and_info(root, SSD,
521 "use ssd allocation scheme");
522 break;
523 case Opt_ssd_spread:
524 btrfs_set_and_info(root, SSD_SPREAD,
525 "use spread ssd allocation scheme");
526 btrfs_set_opt(info->mount_opt, SSD);
527 break;
528 case Opt_nossd:
529 btrfs_set_and_info(root, NOSSD,
530 "not using ssd allocation scheme");
531 btrfs_clear_opt(info->mount_opt, SSD);
532 break;
533 case Opt_barrier:
534 btrfs_clear_and_info(root, NOBARRIER,
535 "turning on barriers");
536 break;
537 case Opt_nobarrier:
538 btrfs_set_and_info(root, NOBARRIER,
539 "turning off barriers");
540 break;
541 case Opt_thread_pool:
542 ret = match_int(&args[0], &intarg);
543 if (ret) {
544 goto out;
545 } else if (intarg > 0) {
546 info->thread_pool_size = intarg;
547 } else {
548 ret = -EINVAL;
549 goto out;
550 }
551 break;
552 case Opt_max_inline:
553 num = match_strdup(&args[0]);
554 if (num) {
555 info->max_inline = memparse(num, NULL);
556 kfree(num);
557
558 if (info->max_inline) {
559 info->max_inline = min_t(u64,
560 info->max_inline,
561 root->sectorsize);
562 }
563 btrfs_info(root->fs_info, "max_inline at %llu",
564 info->max_inline);
565 } else {
566 ret = -ENOMEM;
567 goto out;
568 }
569 break;
570 case Opt_alloc_start:
571 num = match_strdup(&args[0]);
572 if (num) {
573 mutex_lock(&info->chunk_mutex);
574 info->alloc_start = memparse(num, NULL);
575 mutex_unlock(&info->chunk_mutex);
576 kfree(num);
577 btrfs_info(root->fs_info, "allocations start at %llu",
578 info->alloc_start);
579 } else {
580 ret = -ENOMEM;
581 goto out;
582 }
583 break;
584 case Opt_acl:
585 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
586 root->fs_info->sb->s_flags |= MS_POSIXACL;
587 break;
588 #else
589 btrfs_err(root->fs_info,
590 "support for ACL not compiled in!");
591 ret = -EINVAL;
592 goto out;
593 #endif
594 case Opt_noacl:
595 root->fs_info->sb->s_flags &= ~MS_POSIXACL;
596 break;
597 case Opt_notreelog:
598 btrfs_set_and_info(root, NOTREELOG,
599 "disabling tree log");
600 break;
601 case Opt_treelog:
602 btrfs_clear_and_info(root, NOTREELOG,
603 "enabling tree log");
604 break;
605 case Opt_flushoncommit:
606 btrfs_set_and_info(root, FLUSHONCOMMIT,
607 "turning on flush-on-commit");
608 break;
609 case Opt_noflushoncommit:
610 btrfs_clear_and_info(root, FLUSHONCOMMIT,
611 "turning off flush-on-commit");
612 break;
613 case Opt_ratio:
614 ret = match_int(&args[0], &intarg);
615 if (ret) {
616 goto out;
617 } else if (intarg >= 0) {
618 info->metadata_ratio = intarg;
619 btrfs_info(root->fs_info, "metadata ratio %d",
620 info->metadata_ratio);
621 } else {
622 ret = -EINVAL;
623 goto out;
624 }
625 break;
626 case Opt_discard:
627 btrfs_set_and_info(root, DISCARD,
628 "turning on discard");
629 break;
630 case Opt_nodiscard:
631 btrfs_clear_and_info(root, DISCARD,
632 "turning off discard");
633 break;
634 case Opt_space_cache:
635 btrfs_set_and_info(root, SPACE_CACHE,
636 "enabling disk space caching");
637 break;
638 case Opt_rescan_uuid_tree:
639 btrfs_set_opt(info->mount_opt, RESCAN_UUID_TREE);
640 break;
641 case Opt_no_space_cache:
642 btrfs_clear_and_info(root, SPACE_CACHE,
643 "disabling disk space caching");
644 break;
645 case Opt_inode_cache:
646 btrfs_set_pending_and_info(info, INODE_MAP_CACHE,
647 "enabling inode map caching");
648 break;
649 case Opt_noinode_cache:
650 btrfs_clear_pending_and_info(info, INODE_MAP_CACHE,
651 "disabling inode map caching");
652 break;
653 case Opt_clear_cache:
654 btrfs_set_and_info(root, CLEAR_CACHE,
655 "force clearing of disk cache");
656 break;
657 case Opt_user_subvol_rm_allowed:
658 btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
659 break;
660 case Opt_enospc_debug:
661 btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
662 break;
663 case Opt_noenospc_debug:
664 btrfs_clear_opt(info->mount_opt, ENOSPC_DEBUG);
665 break;
666 case Opt_defrag:
667 btrfs_set_and_info(root, AUTO_DEFRAG,
668 "enabling auto defrag");
669 break;
670 case Opt_nodefrag:
671 btrfs_clear_and_info(root, AUTO_DEFRAG,
672 "disabling auto defrag");
673 break;
674 case Opt_recovery:
675 btrfs_info(root->fs_info, "enabling auto recovery");
676 btrfs_set_opt(info->mount_opt, RECOVERY);
677 break;
678 case Opt_skip_balance:
679 btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
680 break;
681 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
682 case Opt_check_integrity_including_extent_data:
683 btrfs_info(root->fs_info,
684 "enabling check integrity including extent data");
685 btrfs_set_opt(info->mount_opt,
686 CHECK_INTEGRITY_INCLUDING_EXTENT_DATA);
687 btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
688 break;
689 case Opt_check_integrity:
690 btrfs_info(root->fs_info, "enabling check integrity");
691 btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
692 break;
693 case Opt_check_integrity_print_mask:
694 ret = match_int(&args[0], &intarg);
695 if (ret) {
696 goto out;
697 } else if (intarg >= 0) {
698 info->check_integrity_print_mask = intarg;
699 btrfs_info(root->fs_info, "check_integrity_print_mask 0x%x",
700 info->check_integrity_print_mask);
701 } else {
702 ret = -EINVAL;
703 goto out;
704 }
705 break;
706 #else
707 case Opt_check_integrity_including_extent_data:
708 case Opt_check_integrity:
709 case Opt_check_integrity_print_mask:
710 btrfs_err(root->fs_info,
711 "support for check_integrity* not compiled in!");
712 ret = -EINVAL;
713 goto out;
714 #endif
715 case Opt_fatal_errors:
716 if (strcmp(args[0].from, "panic") == 0)
717 btrfs_set_opt(info->mount_opt,
718 PANIC_ON_FATAL_ERROR);
719 else if (strcmp(args[0].from, "bug") == 0)
720 btrfs_clear_opt(info->mount_opt,
721 PANIC_ON_FATAL_ERROR);
722 else {
723 ret = -EINVAL;
724 goto out;
725 }
726 break;
727 case Opt_commit_interval:
728 intarg = 0;
729 ret = match_int(&args[0], &intarg);
730 if (ret < 0) {
731 btrfs_err(root->fs_info, "invalid commit interval");
732 ret = -EINVAL;
733 goto out;
734 }
735 if (intarg > 0) {
736 if (intarg > 300) {
737 btrfs_warn(root->fs_info, "excessive commit interval %d",
738 intarg);
739 }
740 info->commit_interval = intarg;
741 } else {
742 btrfs_info(root->fs_info, "using default commit interval %ds",
743 BTRFS_DEFAULT_COMMIT_INTERVAL);
744 info->commit_interval = BTRFS_DEFAULT_COMMIT_INTERVAL;
745 }
746 break;
747 #ifdef CONFIG_BTRFS_DEBUG
748 case Opt_fragment_all:
749 btrfs_info(root->fs_info, "fragmenting all space");
750 btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
751 btrfs_set_opt(info->mount_opt, FRAGMENT_METADATA);
752 break;
753 case Opt_fragment_metadata:
754 btrfs_info(root->fs_info, "fragmenting metadata");
755 btrfs_set_opt(info->mount_opt,
756 FRAGMENT_METADATA);
757 break;
758 case Opt_fragment_data:
759 btrfs_info(root->fs_info, "fragmenting data");
760 btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
761 break;
762 #endif
763 case Opt_err:
764 btrfs_info(root->fs_info, "unrecognized mount option '%s'", p);
765 ret = -EINVAL;
766 goto out;
767 default:
768 break;
769 }
770 }
771 out:
772 if (!ret && btrfs_test_opt(root, SPACE_CACHE))
773 btrfs_info(root->fs_info, "disk space caching is enabled");
774 kfree(orig);
775 return ret;
776 }
777
778 /*
779 * Parse mount options that are required early in the mount process.
780 *
781 * All other options will be parsed on much later in the mount process and
782 * only when we need to allocate a new super block.
783 */
784 static int btrfs_parse_early_options(const char *options, fmode_t flags,
785 void *holder, char **subvol_name, u64 *subvol_objectid,
786 struct btrfs_fs_devices **fs_devices)
787 {
788 substring_t args[MAX_OPT_ARGS];
789 char *device_name, *opts, *orig, *p;
790 char *num = NULL;
791 int error = 0;
792
793 if (!options)
794 return 0;
795
796 /*
797 * strsep changes the string, duplicate it because parse_options
798 * gets called twice
799 */
800 opts = kstrdup(options, GFP_KERNEL);
801 if (!opts)
802 return -ENOMEM;
803 orig = opts;
804
805 while ((p = strsep(&opts, ",")) != NULL) {
806 int token;
807 if (!*p)
808 continue;
809
810 token = match_token(p, tokens, args);
811 switch (token) {
812 case Opt_subvol:
813 kfree(*subvol_name);
814 *subvol_name = match_strdup(&args[0]);
815 if (!*subvol_name) {
816 error = -ENOMEM;
817 goto out;
818 }
819 break;
820 case Opt_subvolid:
821 num = match_strdup(&args[0]);
822 if (num) {
823 *subvol_objectid = memparse(num, NULL);
824 kfree(num);
825 /* we want the original fs_tree */
826 if (!*subvol_objectid)
827 *subvol_objectid =
828 BTRFS_FS_TREE_OBJECTID;
829 } else {
830 error = -EINVAL;
831 goto out;
832 }
833 break;
834 case Opt_subvolrootid:
835 printk(KERN_WARNING
836 "BTRFS: 'subvolrootid' mount option is deprecated and has "
837 "no effect\n");
838 break;
839 case Opt_device:
840 device_name = match_strdup(&args[0]);
841 if (!device_name) {
842 error = -ENOMEM;
843 goto out;
844 }
845 error = btrfs_scan_one_device(device_name,
846 flags, holder, fs_devices);
847 kfree(device_name);
848 if (error)
849 goto out;
850 break;
851 default:
852 break;
853 }
854 }
855
856 out:
857 kfree(orig);
858 return error;
859 }
860
861 static char *get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
862 u64 subvol_objectid)
863 {
864 struct btrfs_root *root = fs_info->tree_root;
865 struct btrfs_root *fs_root;
866 struct btrfs_root_ref *root_ref;
867 struct btrfs_inode_ref *inode_ref;
868 struct btrfs_key key;
869 struct btrfs_path *path = NULL;
870 char *name = NULL, *ptr;
871 u64 dirid;
872 int len;
873 int ret;
874
875 path = btrfs_alloc_path();
876 if (!path) {
877 ret = -ENOMEM;
878 goto err;
879 }
880 path->leave_spinning = 1;
881
882 name = kmalloc(PATH_MAX, GFP_NOFS);
883 if (!name) {
884 ret = -ENOMEM;
885 goto err;
886 }
887 ptr = name + PATH_MAX - 1;
888 ptr[0] = '\0';
889
890 /*
891 * Walk up the subvolume trees in the tree of tree roots by root
892 * backrefs until we hit the top-level subvolume.
893 */
894 while (subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
895 key.objectid = subvol_objectid;
896 key.type = BTRFS_ROOT_BACKREF_KEY;
897 key.offset = (u64)-1;
898
899 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
900 if (ret < 0) {
901 goto err;
902 } else if (ret > 0) {
903 ret = btrfs_previous_item(root, path, subvol_objectid,
904 BTRFS_ROOT_BACKREF_KEY);
905 if (ret < 0) {
906 goto err;
907 } else if (ret > 0) {
908 ret = -ENOENT;
909 goto err;
910 }
911 }
912
913 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
914 subvol_objectid = key.offset;
915
916 root_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
917 struct btrfs_root_ref);
918 len = btrfs_root_ref_name_len(path->nodes[0], root_ref);
919 ptr -= len + 1;
920 if (ptr < name) {
921 ret = -ENAMETOOLONG;
922 goto err;
923 }
924 read_extent_buffer(path->nodes[0], ptr + 1,
925 (unsigned long)(root_ref + 1), len);
926 ptr[0] = '/';
927 dirid = btrfs_root_ref_dirid(path->nodes[0], root_ref);
928 btrfs_release_path(path);
929
930 key.objectid = subvol_objectid;
931 key.type = BTRFS_ROOT_ITEM_KEY;
932 key.offset = (u64)-1;
933 fs_root = btrfs_read_fs_root_no_name(fs_info, &key);
934 if (IS_ERR(fs_root)) {
935 ret = PTR_ERR(fs_root);
936 goto err;
937 }
938
939 /*
940 * Walk up the filesystem tree by inode refs until we hit the
941 * root directory.
942 */
943 while (dirid != BTRFS_FIRST_FREE_OBJECTID) {
944 key.objectid = dirid;
945 key.type = BTRFS_INODE_REF_KEY;
946 key.offset = (u64)-1;
947
948 ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0);
949 if (ret < 0) {
950 goto err;
951 } else if (ret > 0) {
952 ret = btrfs_previous_item(fs_root, path, dirid,
953 BTRFS_INODE_REF_KEY);
954 if (ret < 0) {
955 goto err;
956 } else if (ret > 0) {
957 ret = -ENOENT;
958 goto err;
959 }
960 }
961
962 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
963 dirid = key.offset;
964
965 inode_ref = btrfs_item_ptr(path->nodes[0],
966 path->slots[0],
967 struct btrfs_inode_ref);
968 len = btrfs_inode_ref_name_len(path->nodes[0],
969 inode_ref);
970 ptr -= len + 1;
971 if (ptr < name) {
972 ret = -ENAMETOOLONG;
973 goto err;
974 }
975 read_extent_buffer(path->nodes[0], ptr + 1,
976 (unsigned long)(inode_ref + 1), len);
977 ptr[0] = '/';
978 btrfs_release_path(path);
979 }
980 }
981
982 btrfs_free_path(path);
983 if (ptr == name + PATH_MAX - 1) {
984 name[0] = '/';
985 name[1] = '\0';
986 } else {
987 memmove(name, ptr, name + PATH_MAX - ptr);
988 }
989 return name;
990
991 err:
992 btrfs_free_path(path);
993 kfree(name);
994 return ERR_PTR(ret);
995 }
996
997 static int get_default_subvol_objectid(struct btrfs_fs_info *fs_info, u64 *objectid)
998 {
999 struct btrfs_root *root = fs_info->tree_root;
1000 struct btrfs_dir_item *di;
1001 struct btrfs_path *path;
1002 struct btrfs_key location;
1003 u64 dir_id;
1004
1005 path = btrfs_alloc_path();
1006 if (!path)
1007 return -ENOMEM;
1008 path->leave_spinning = 1;
1009
1010 /*
1011 * Find the "default" dir item which points to the root item that we
1012 * will mount by default if we haven't been given a specific subvolume
1013 * to mount.
1014 */
1015 dir_id = btrfs_super_root_dir(fs_info->super_copy);
1016 di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
1017 if (IS_ERR(di)) {
1018 btrfs_free_path(path);
1019 return PTR_ERR(di);
1020 }
1021 if (!di) {
1022 /*
1023 * Ok the default dir item isn't there. This is weird since
1024 * it's always been there, but don't freak out, just try and
1025 * mount the top-level subvolume.
1026 */
1027 btrfs_free_path(path);
1028 *objectid = BTRFS_FS_TREE_OBJECTID;
1029 return 0;
1030 }
1031
1032 btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
1033 btrfs_free_path(path);
1034 *objectid = location.objectid;
1035 return 0;
1036 }
1037
1038 static int btrfs_fill_super(struct super_block *sb,
1039 struct btrfs_fs_devices *fs_devices,
1040 void *data, int silent)
1041 {
1042 struct inode *inode;
1043 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1044 struct btrfs_key key;
1045 int err;
1046
1047 sb->s_maxbytes = MAX_LFS_FILESIZE;
1048 sb->s_magic = BTRFS_SUPER_MAGIC;
1049 sb->s_op = &btrfs_super_ops;
1050 sb->s_d_op = &btrfs_dentry_operations;
1051 sb->s_export_op = &btrfs_export_ops;
1052 sb->s_xattr = btrfs_xattr_handlers;
1053 sb->s_time_gran = 1;
1054 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
1055 sb->s_flags |= MS_POSIXACL;
1056 #endif
1057 sb->s_flags |= MS_I_VERSION;
1058 sb->s_iflags |= SB_I_CGROUPWB;
1059 err = open_ctree(sb, fs_devices, (char *)data);
1060 if (err) {
1061 printk(KERN_ERR "BTRFS: open_ctree failed\n");
1062 return err;
1063 }
1064
1065 key.objectid = BTRFS_FIRST_FREE_OBJECTID;
1066 key.type = BTRFS_INODE_ITEM_KEY;
1067 key.offset = 0;
1068 inode = btrfs_iget(sb, &key, fs_info->fs_root, NULL);
1069 if (IS_ERR(inode)) {
1070 err = PTR_ERR(inode);
1071 goto fail_close;
1072 }
1073
1074 sb->s_root = d_make_root(inode);
1075 if (!sb->s_root) {
1076 err = -ENOMEM;
1077 goto fail_close;
1078 }
1079
1080 save_mount_options(sb, data);
1081 cleancache_init_fs(sb);
1082 sb->s_flags |= MS_ACTIVE;
1083 return 0;
1084
1085 fail_close:
1086 close_ctree(fs_info->tree_root);
1087 return err;
1088 }
1089
1090 int btrfs_sync_fs(struct super_block *sb, int wait)
1091 {
1092 struct btrfs_trans_handle *trans;
1093 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1094 struct btrfs_root *root = fs_info->tree_root;
1095
1096 trace_btrfs_sync_fs(wait);
1097
1098 if (!wait) {
1099 filemap_flush(fs_info->btree_inode->i_mapping);
1100 return 0;
1101 }
1102
1103 btrfs_wait_ordered_roots(fs_info, -1);
1104
1105 trans = btrfs_attach_transaction_barrier(root);
1106 if (IS_ERR(trans)) {
1107 /* no transaction, don't bother */
1108 if (PTR_ERR(trans) == -ENOENT) {
1109 /*
1110 * Exit unless we have some pending changes
1111 * that need to go through commit
1112 */
1113 if (fs_info->pending_changes == 0)
1114 return 0;
1115 /*
1116 * A non-blocking test if the fs is frozen. We must not
1117 * start a new transaction here otherwise a deadlock
1118 * happens. The pending operations are delayed to the
1119 * next commit after thawing.
1120 */
1121 if (__sb_start_write(sb, SB_FREEZE_WRITE, false))
1122 __sb_end_write(sb, SB_FREEZE_WRITE);
1123 else
1124 return 0;
1125 trans = btrfs_start_transaction(root, 0);
1126 }
1127 if (IS_ERR(trans))
1128 return PTR_ERR(trans);
1129 }
1130 return btrfs_commit_transaction(trans, root);
1131 }
1132
1133 static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
1134 {
1135 struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
1136 struct btrfs_root *root = info->tree_root;
1137 char *compress_type;
1138
1139 if (btrfs_test_opt(root, DEGRADED))
1140 seq_puts(seq, ",degraded");
1141 if (btrfs_test_opt(root, NODATASUM))
1142 seq_puts(seq, ",nodatasum");
1143 if (btrfs_test_opt(root, NODATACOW))
1144 seq_puts(seq, ",nodatacow");
1145 if (btrfs_test_opt(root, NOBARRIER))
1146 seq_puts(seq, ",nobarrier");
1147 if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE)
1148 seq_printf(seq, ",max_inline=%llu", info->max_inline);
1149 if (info->alloc_start != 0)
1150 seq_printf(seq, ",alloc_start=%llu", info->alloc_start);
1151 if (info->thread_pool_size != min_t(unsigned long,
1152 num_online_cpus() + 2, 8))
1153 seq_printf(seq, ",thread_pool=%d", info->thread_pool_size);
1154 if (btrfs_test_opt(root, COMPRESS)) {
1155 if (info->compress_type == BTRFS_COMPRESS_ZLIB)
1156 compress_type = "zlib";
1157 else
1158 compress_type = "lzo";
1159 if (btrfs_test_opt(root, FORCE_COMPRESS))
1160 seq_printf(seq, ",compress-force=%s", compress_type);
1161 else
1162 seq_printf(seq, ",compress=%s", compress_type);
1163 }
1164 if (btrfs_test_opt(root, NOSSD))
1165 seq_puts(seq, ",nossd");
1166 if (btrfs_test_opt(root, SSD_SPREAD))
1167 seq_puts(seq, ",ssd_spread");
1168 else if (btrfs_test_opt(root, SSD))
1169 seq_puts(seq, ",ssd");
1170 if (btrfs_test_opt(root, NOTREELOG))
1171 seq_puts(seq, ",notreelog");
1172 if (btrfs_test_opt(root, FLUSHONCOMMIT))
1173 seq_puts(seq, ",flushoncommit");
1174 if (btrfs_test_opt(root, DISCARD))
1175 seq_puts(seq, ",discard");
1176 if (!(root->fs_info->sb->s_flags & MS_POSIXACL))
1177 seq_puts(seq, ",noacl");
1178 if (btrfs_test_opt(root, SPACE_CACHE))
1179 seq_puts(seq, ",space_cache");
1180 else
1181 seq_puts(seq, ",nospace_cache");
1182 if (btrfs_test_opt(root, RESCAN_UUID_TREE))
1183 seq_puts(seq, ",rescan_uuid_tree");
1184 if (btrfs_test_opt(root, CLEAR_CACHE))
1185 seq_puts(seq, ",clear_cache");
1186 if (btrfs_test_opt(root, USER_SUBVOL_RM_ALLOWED))
1187 seq_puts(seq, ",user_subvol_rm_allowed");
1188 if (btrfs_test_opt(root, ENOSPC_DEBUG))
1189 seq_puts(seq, ",enospc_debug");
1190 if (btrfs_test_opt(root, AUTO_DEFRAG))
1191 seq_puts(seq, ",autodefrag");
1192 if (btrfs_test_opt(root, INODE_MAP_CACHE))
1193 seq_puts(seq, ",inode_cache");
1194 if (btrfs_test_opt(root, SKIP_BALANCE))
1195 seq_puts(seq, ",skip_balance");
1196 if (btrfs_test_opt(root, RECOVERY))
1197 seq_puts(seq, ",recovery");
1198 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
1199 if (btrfs_test_opt(root, CHECK_INTEGRITY_INCLUDING_EXTENT_DATA))
1200 seq_puts(seq, ",check_int_data");
1201 else if (btrfs_test_opt(root, CHECK_INTEGRITY))
1202 seq_puts(seq, ",check_int");
1203 if (info->check_integrity_print_mask)
1204 seq_printf(seq, ",check_int_print_mask=%d",
1205 info->check_integrity_print_mask);
1206 #endif
1207 if (info->metadata_ratio)
1208 seq_printf(seq, ",metadata_ratio=%d",
1209 info->metadata_ratio);
1210 if (btrfs_test_opt(root, PANIC_ON_FATAL_ERROR))
1211 seq_puts(seq, ",fatal_errors=panic");
1212 if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL)
1213 seq_printf(seq, ",commit=%d", info->commit_interval);
1214 #ifdef CONFIG_BTRFS_DEBUG
1215 if (btrfs_test_opt(root, FRAGMENT_DATA))
1216 seq_puts(seq, ",fragment=data");
1217 if (btrfs_test_opt(root, FRAGMENT_METADATA))
1218 seq_puts(seq, ",fragment=metadata");
1219 #endif
1220 seq_printf(seq, ",subvolid=%llu",
1221 BTRFS_I(d_inode(dentry))->root->root_key.objectid);
1222 seq_puts(seq, ",subvol=");
1223 seq_dentry(seq, dentry, " \t\n\\");
1224 return 0;
1225 }
1226
1227 static int btrfs_test_super(struct super_block *s, void *data)
1228 {
1229 struct btrfs_fs_info *p = data;
1230 struct btrfs_fs_info *fs_info = btrfs_sb(s);
1231
1232 return fs_info->fs_devices == p->fs_devices;
1233 }
1234
1235 static int btrfs_set_super(struct super_block *s, void *data)
1236 {
1237 int err = set_anon_super(s, data);
1238 if (!err)
1239 s->s_fs_info = data;
1240 return err;
1241 }
1242
1243 /*
1244 * subvolumes are identified by ino 256
1245 */
1246 static inline int is_subvolume_inode(struct inode *inode)
1247 {
1248 if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
1249 return 1;
1250 return 0;
1251 }
1252
1253 /*
1254 * This will add subvolid=0 to the argument string while removing any subvol=
1255 * and subvolid= arguments to make sure we get the top-level root for path
1256 * walking to the subvol we want.
1257 */
1258 static char *setup_root_args(char *args)
1259 {
1260 char *buf, *dst, *sep;
1261
1262 if (!args)
1263 return kstrdup("subvolid=0", GFP_NOFS);
1264
1265 /* The worst case is that we add ",subvolid=0" to the end. */
1266 buf = dst = kmalloc(strlen(args) + strlen(",subvolid=0") + 1, GFP_NOFS);
1267 if (!buf)
1268 return NULL;
1269
1270 while (1) {
1271 sep = strchrnul(args, ',');
1272 if (!strstarts(args, "subvol=") &&
1273 !strstarts(args, "subvolid=")) {
1274 memcpy(dst, args, sep - args);
1275 dst += sep - args;
1276 *dst++ = ',';
1277 }
1278 if (*sep)
1279 args = sep + 1;
1280 else
1281 break;
1282 }
1283 strcpy(dst, "subvolid=0");
1284
1285 return buf;
1286 }
1287
1288 static struct dentry *mount_subvol(const char *subvol_name, u64 subvol_objectid,
1289 int flags, const char *device_name,
1290 char *data)
1291 {
1292 struct dentry *root;
1293 struct vfsmount *mnt = NULL;
1294 char *newargs;
1295 int ret;
1296
1297 newargs = setup_root_args(data);
1298 if (!newargs) {
1299 root = ERR_PTR(-ENOMEM);
1300 goto out;
1301 }
1302
1303 mnt = vfs_kern_mount(&btrfs_fs_type, flags, device_name, newargs);
1304 if (PTR_ERR_OR_ZERO(mnt) == -EBUSY) {
1305 if (flags & MS_RDONLY) {
1306 mnt = vfs_kern_mount(&btrfs_fs_type, flags & ~MS_RDONLY,
1307 device_name, newargs);
1308 } else {
1309 mnt = vfs_kern_mount(&btrfs_fs_type, flags | MS_RDONLY,
1310 device_name, newargs);
1311 if (IS_ERR(mnt)) {
1312 root = ERR_CAST(mnt);
1313 mnt = NULL;
1314 goto out;
1315 }
1316
1317 down_write(&mnt->mnt_sb->s_umount);
1318 ret = btrfs_remount(mnt->mnt_sb, &flags, NULL);
1319 up_write(&mnt->mnt_sb->s_umount);
1320 if (ret < 0) {
1321 root = ERR_PTR(ret);
1322 goto out;
1323 }
1324 }
1325 }
1326 if (IS_ERR(mnt)) {
1327 root = ERR_CAST(mnt);
1328 mnt = NULL;
1329 goto out;
1330 }
1331
1332 if (!subvol_name) {
1333 if (!subvol_objectid) {
1334 ret = get_default_subvol_objectid(btrfs_sb(mnt->mnt_sb),
1335 &subvol_objectid);
1336 if (ret) {
1337 root = ERR_PTR(ret);
1338 goto out;
1339 }
1340 }
1341 subvol_name = get_subvol_name_from_objectid(btrfs_sb(mnt->mnt_sb),
1342 subvol_objectid);
1343 if (IS_ERR(subvol_name)) {
1344 root = ERR_CAST(subvol_name);
1345 subvol_name = NULL;
1346 goto out;
1347 }
1348
1349 }
1350
1351 root = mount_subtree(mnt, subvol_name);
1352 /* mount_subtree() drops our reference on the vfsmount. */
1353 mnt = NULL;
1354
1355 if (!IS_ERR(root)) {
1356 struct super_block *s = root->d_sb;
1357 struct inode *root_inode = d_inode(root);
1358 u64 root_objectid = BTRFS_I(root_inode)->root->root_key.objectid;
1359
1360 ret = 0;
1361 if (!is_subvolume_inode(root_inode)) {
1362 pr_err("BTRFS: '%s' is not a valid subvolume\n",
1363 subvol_name);
1364 ret = -EINVAL;
1365 }
1366 if (subvol_objectid && root_objectid != subvol_objectid) {
1367 /*
1368 * This will also catch a race condition where a
1369 * subvolume which was passed by ID is renamed and
1370 * another subvolume is renamed over the old location.
1371 */
1372 pr_err("BTRFS: subvol '%s' does not match subvolid %llu\n",
1373 subvol_name, subvol_objectid);
1374 ret = -EINVAL;
1375 }
1376 if (ret) {
1377 dput(root);
1378 root = ERR_PTR(ret);
1379 deactivate_locked_super(s);
1380 }
1381 }
1382
1383 out:
1384 mntput(mnt);
1385 kfree(newargs);
1386 kfree(subvol_name);
1387 return root;
1388 }
1389
1390 static int parse_security_options(char *orig_opts,
1391 struct security_mnt_opts *sec_opts)
1392 {
1393 char *secdata = NULL;
1394 int ret = 0;
1395
1396 secdata = alloc_secdata();
1397 if (!secdata)
1398 return -ENOMEM;
1399 ret = security_sb_copy_data(orig_opts, secdata);
1400 if (ret) {
1401 free_secdata(secdata);
1402 return ret;
1403 }
1404 ret = security_sb_parse_opts_str(secdata, sec_opts);
1405 free_secdata(secdata);
1406 return ret;
1407 }
1408
1409 static int setup_security_options(struct btrfs_fs_info *fs_info,
1410 struct super_block *sb,
1411 struct security_mnt_opts *sec_opts)
1412 {
1413 int ret = 0;
1414
1415 /*
1416 * Call security_sb_set_mnt_opts() to check whether new sec_opts
1417 * is valid.
1418 */
1419 ret = security_sb_set_mnt_opts(sb, sec_opts, 0, NULL);
1420 if (ret)
1421 return ret;
1422
1423 #ifdef CONFIG_SECURITY
1424 if (!fs_info->security_opts.num_mnt_opts) {
1425 /* first time security setup, copy sec_opts to fs_info */
1426 memcpy(&fs_info->security_opts, sec_opts, sizeof(*sec_opts));
1427 } else {
1428 /*
1429 * Since SELinux(the only one supports security_mnt_opts) does
1430 * NOT support changing context during remount/mount same sb,
1431 * This must be the same or part of the same security options,
1432 * just free it.
1433 */
1434 security_free_mnt_opts(sec_opts);
1435 }
1436 #endif
1437 return ret;
1438 }
1439
1440 /*
1441 * Find a superblock for the given device / mount point.
1442 *
1443 * Note: This is based on get_sb_bdev from fs/super.c with a few additions
1444 * for multiple device setup. Make sure to keep it in sync.
1445 */
1446 static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
1447 const char *device_name, void *data)
1448 {
1449 struct block_device *bdev = NULL;
1450 struct super_block *s;
1451 struct btrfs_fs_devices *fs_devices = NULL;
1452 struct btrfs_fs_info *fs_info = NULL;
1453 struct security_mnt_opts new_sec_opts;
1454 fmode_t mode = FMODE_READ;
1455 char *subvol_name = NULL;
1456 u64 subvol_objectid = 0;
1457 int error = 0;
1458
1459 if (!(flags & MS_RDONLY))
1460 mode |= FMODE_WRITE;
1461
1462 error = btrfs_parse_early_options(data, mode, fs_type,
1463 &subvol_name, &subvol_objectid,
1464 &fs_devices);
1465 if (error) {
1466 kfree(subvol_name);
1467 return ERR_PTR(error);
1468 }
1469
1470 if (subvol_name || subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
1471 /* mount_subvol() will free subvol_name. */
1472 return mount_subvol(subvol_name, subvol_objectid, flags,
1473 device_name, data);
1474 }
1475
1476 security_init_mnt_opts(&new_sec_opts);
1477 if (data) {
1478 error = parse_security_options(data, &new_sec_opts);
1479 if (error)
1480 return ERR_PTR(error);
1481 }
1482
1483 error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices);
1484 if (error)
1485 goto error_sec_opts;
1486
1487 /*
1488 * Setup a dummy root and fs_info for test/set super. This is because
1489 * we don't actually fill this stuff out until open_ctree, but we need
1490 * it for searching for existing supers, so this lets us do that and
1491 * then open_ctree will properly initialize everything later.
1492 */
1493 fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_NOFS);
1494 if (!fs_info) {
1495 error = -ENOMEM;
1496 goto error_sec_opts;
1497 }
1498
1499 fs_info->fs_devices = fs_devices;
1500
1501 fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
1502 fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
1503 security_init_mnt_opts(&fs_info->security_opts);
1504 if (!fs_info->super_copy || !fs_info->super_for_commit) {
1505 error = -ENOMEM;
1506 goto error_fs_info;
1507 }
1508
1509 error = btrfs_open_devices(fs_devices, mode, fs_type);
1510 if (error)
1511 goto error_fs_info;
1512
1513 if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
1514 error = -EACCES;
1515 goto error_close_devices;
1516 }
1517
1518 bdev = fs_devices->latest_bdev;
1519 s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | MS_NOSEC,
1520 fs_info);
1521 if (IS_ERR(s)) {
1522 error = PTR_ERR(s);
1523 goto error_close_devices;
1524 }
1525
1526 if (s->s_root) {
1527 btrfs_close_devices(fs_devices);
1528 free_fs_info(fs_info);
1529 if ((flags ^ s->s_flags) & MS_RDONLY)
1530 error = -EBUSY;
1531 } else {
1532 char b[BDEVNAME_SIZE];
1533
1534 strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
1535 btrfs_sb(s)->bdev_holder = fs_type;
1536 error = btrfs_fill_super(s, fs_devices, data,
1537 flags & MS_SILENT ? 1 : 0);
1538 }
1539 if (error) {
1540 deactivate_locked_super(s);
1541 goto error_sec_opts;
1542 }
1543
1544 fs_info = btrfs_sb(s);
1545 error = setup_security_options(fs_info, s, &new_sec_opts);
1546 if (error) {
1547 deactivate_locked_super(s);
1548 goto error_sec_opts;
1549 }
1550
1551 return dget(s->s_root);
1552
1553 error_close_devices:
1554 btrfs_close_devices(fs_devices);
1555 error_fs_info:
1556 free_fs_info(fs_info);
1557 error_sec_opts:
1558 security_free_mnt_opts(&new_sec_opts);
1559 return ERR_PTR(error);
1560 }
1561
1562 static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
1563 int new_pool_size, int old_pool_size)
1564 {
1565 if (new_pool_size == old_pool_size)
1566 return;
1567
1568 fs_info->thread_pool_size = new_pool_size;
1569
1570 btrfs_info(fs_info, "resize thread pool %d -> %d",
1571 old_pool_size, new_pool_size);
1572
1573 btrfs_workqueue_set_max(fs_info->workers, new_pool_size);
1574 btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size);
1575 btrfs_workqueue_set_max(fs_info->submit_workers, new_pool_size);
1576 btrfs_workqueue_set_max(fs_info->caching_workers, new_pool_size);
1577 btrfs_workqueue_set_max(fs_info->endio_workers, new_pool_size);
1578 btrfs_workqueue_set_max(fs_info->endio_meta_workers, new_pool_size);
1579 btrfs_workqueue_set_max(fs_info->endio_meta_write_workers,
1580 new_pool_size);
1581 btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size);
1582 btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
1583 btrfs_workqueue_set_max(fs_info->delayed_workers, new_pool_size);
1584 btrfs_workqueue_set_max(fs_info->readahead_workers, new_pool_size);
1585 btrfs_workqueue_set_max(fs_info->scrub_wr_completion_workers,
1586 new_pool_size);
1587 }
1588
1589 static inline void btrfs_remount_prepare(struct btrfs_fs_info *fs_info)
1590 {
1591 set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1592 }
1593
1594 static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info,
1595 unsigned long old_opts, int flags)
1596 {
1597 if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1598 (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1599 (flags & MS_RDONLY))) {
1600 /* wait for any defraggers to finish */
1601 wait_event(fs_info->transaction_wait,
1602 (atomic_read(&fs_info->defrag_running) == 0));
1603 if (flags & MS_RDONLY)
1604 sync_filesystem(fs_info->sb);
1605 }
1606 }
1607
1608 static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
1609 unsigned long old_opts)
1610 {
1611 /*
1612 * We need cleanup all defragable inodes if the autodefragment is
1613 * close or the fs is R/O.
1614 */
1615 if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1616 (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1617 (fs_info->sb->s_flags & MS_RDONLY))) {
1618 btrfs_cleanup_defrag_inodes(fs_info);
1619 }
1620
1621 clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1622 }
1623
1624 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
1625 {
1626 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1627 struct btrfs_root *root = fs_info->tree_root;
1628 unsigned old_flags = sb->s_flags;
1629 unsigned long old_opts = fs_info->mount_opt;
1630 unsigned long old_compress_type = fs_info->compress_type;
1631 u64 old_max_inline = fs_info->max_inline;
1632 u64 old_alloc_start = fs_info->alloc_start;
1633 int old_thread_pool_size = fs_info->thread_pool_size;
1634 unsigned int old_metadata_ratio = fs_info->metadata_ratio;
1635 int ret;
1636
1637 sync_filesystem(sb);
1638 btrfs_remount_prepare(fs_info);
1639
1640 if (data) {
1641 struct security_mnt_opts new_sec_opts;
1642
1643 security_init_mnt_opts(&new_sec_opts);
1644 ret = parse_security_options(data, &new_sec_opts);
1645 if (ret)
1646 goto restore;
1647 ret = setup_security_options(fs_info, sb,
1648 &new_sec_opts);
1649 if (ret) {
1650 security_free_mnt_opts(&new_sec_opts);
1651 goto restore;
1652 }
1653 }
1654
1655 ret = btrfs_parse_options(root, data);
1656 if (ret) {
1657 ret = -EINVAL;
1658 goto restore;
1659 }
1660
1661 btrfs_remount_begin(fs_info, old_opts, *flags);
1662 btrfs_resize_thread_pool(fs_info,
1663 fs_info->thread_pool_size, old_thread_pool_size);
1664
1665 if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1666 goto out;
1667
1668 if (*flags & MS_RDONLY) {
1669 /*
1670 * this also happens on 'umount -rf' or on shutdown, when
1671 * the filesystem is busy.
1672 */
1673 cancel_work_sync(&fs_info->async_reclaim_work);
1674
1675 /* wait for the uuid_scan task to finish */
1676 down(&fs_info->uuid_tree_rescan_sem);
1677 /* avoid complains from lockdep et al. */
1678 up(&fs_info->uuid_tree_rescan_sem);
1679
1680 sb->s_flags |= MS_RDONLY;
1681
1682 /*
1683 * Setting MS_RDONLY will put the cleaner thread to
1684 * sleep at the next loop if it's already active.
1685 * If it's already asleep, we'll leave unused block
1686 * groups on disk until we're mounted read-write again
1687 * unless we clean them up here.
1688 */
1689 btrfs_delete_unused_bgs(fs_info);
1690
1691 btrfs_dev_replace_suspend_for_unmount(fs_info);
1692 btrfs_scrub_cancel(fs_info);
1693 btrfs_pause_balance(fs_info);
1694
1695 ret = btrfs_commit_super(root);
1696 if (ret)
1697 goto restore;
1698 } else {
1699 if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state)) {
1700 btrfs_err(fs_info,
1701 "Remounting read-write after error is not allowed");
1702 ret = -EINVAL;
1703 goto restore;
1704 }
1705 if (fs_info->fs_devices->rw_devices == 0) {
1706 ret = -EACCES;
1707 goto restore;
1708 }
1709
1710 if (fs_info->fs_devices->missing_devices >
1711 fs_info->num_tolerated_disk_barrier_failures &&
1712 !(*flags & MS_RDONLY)) {
1713 btrfs_warn(fs_info,
1714 "too many missing devices, writeable remount is not allowed");
1715 ret = -EACCES;
1716 goto restore;
1717 }
1718
1719 if (btrfs_super_log_root(fs_info->super_copy) != 0) {
1720 ret = -EINVAL;
1721 goto restore;
1722 }
1723
1724 ret = btrfs_cleanup_fs_roots(fs_info);
1725 if (ret)
1726 goto restore;
1727
1728 /* recover relocation */
1729 mutex_lock(&fs_info->cleaner_mutex);
1730 ret = btrfs_recover_relocation(root);
1731 mutex_unlock(&fs_info->cleaner_mutex);
1732 if (ret)
1733 goto restore;
1734
1735 ret = btrfs_resume_balance_async(fs_info);
1736 if (ret)
1737 goto restore;
1738
1739 ret = btrfs_resume_dev_replace_async(fs_info);
1740 if (ret) {
1741 btrfs_warn(fs_info, "failed to resume dev_replace");
1742 goto restore;
1743 }
1744
1745 if (!fs_info->uuid_root) {
1746 btrfs_info(fs_info, "creating UUID tree");
1747 ret = btrfs_create_uuid_tree(fs_info);
1748 if (ret) {
1749 btrfs_warn(fs_info, "failed to create the UUID tree %d", ret);
1750 goto restore;
1751 }
1752 }
1753 sb->s_flags &= ~MS_RDONLY;
1754 }
1755 out:
1756 wake_up_process(fs_info->transaction_kthread);
1757 btrfs_remount_cleanup(fs_info, old_opts);
1758 return 0;
1759
1760 restore:
1761 /* We've hit an error - don't reset MS_RDONLY */
1762 if (sb->s_flags & MS_RDONLY)
1763 old_flags |= MS_RDONLY;
1764 sb->s_flags = old_flags;
1765 fs_info->mount_opt = old_opts;
1766 fs_info->compress_type = old_compress_type;
1767 fs_info->max_inline = old_max_inline;
1768 mutex_lock(&fs_info->chunk_mutex);
1769 fs_info->alloc_start = old_alloc_start;
1770 mutex_unlock(&fs_info->chunk_mutex);
1771 btrfs_resize_thread_pool(fs_info,
1772 old_thread_pool_size, fs_info->thread_pool_size);
1773 fs_info->metadata_ratio = old_metadata_ratio;
1774 btrfs_remount_cleanup(fs_info, old_opts);
1775 return ret;
1776 }
1777
1778 /* Used to sort the devices by max_avail(descending sort) */
1779 static int btrfs_cmp_device_free_bytes(const void *dev_info1,
1780 const void *dev_info2)
1781 {
1782 if (((struct btrfs_device_info *)dev_info1)->max_avail >
1783 ((struct btrfs_device_info *)dev_info2)->max_avail)
1784 return -1;
1785 else if (((struct btrfs_device_info *)dev_info1)->max_avail <
1786 ((struct btrfs_device_info *)dev_info2)->max_avail)
1787 return 1;
1788 else
1789 return 0;
1790 }
1791
1792 /*
1793 * sort the devices by max_avail, in which max free extent size of each device
1794 * is stored.(Descending Sort)
1795 */
1796 static inline void btrfs_descending_sort_devices(
1797 struct btrfs_device_info *devices,
1798 size_t nr_devices)
1799 {
1800 sort(devices, nr_devices, sizeof(struct btrfs_device_info),
1801 btrfs_cmp_device_free_bytes, NULL);
1802 }
1803
1804 /*
1805 * The helper to calc the free space on the devices that can be used to store
1806 * file data.
1807 */
1808 static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes)
1809 {
1810 struct btrfs_fs_info *fs_info = root->fs_info;
1811 struct btrfs_device_info *devices_info;
1812 struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
1813 struct btrfs_device *device;
1814 u64 skip_space;
1815 u64 type;
1816 u64 avail_space;
1817 u64 used_space;
1818 u64 min_stripe_size;
1819 int min_stripes = 1, num_stripes = 1;
1820 int i = 0, nr_devices;
1821 int ret;
1822
1823 /*
1824 * We aren't under the device list lock, so this is racey-ish, but good
1825 * enough for our purposes.
1826 */
1827 nr_devices = fs_info->fs_devices->open_devices;
1828 if (!nr_devices) {
1829 smp_mb();
1830 nr_devices = fs_info->fs_devices->open_devices;
1831 ASSERT(nr_devices);
1832 if (!nr_devices) {
1833 *free_bytes = 0;
1834 return 0;
1835 }
1836 }
1837
1838 devices_info = kmalloc_array(nr_devices, sizeof(*devices_info),
1839 GFP_NOFS);
1840 if (!devices_info)
1841 return -ENOMEM;
1842
1843 /* calc min stripe number for data space alloction */
1844 type = btrfs_get_alloc_profile(root, 1);
1845 if (type & BTRFS_BLOCK_GROUP_RAID0) {
1846 min_stripes = 2;
1847 num_stripes = nr_devices;
1848 } else if (type & BTRFS_BLOCK_GROUP_RAID1) {
1849 min_stripes = 2;
1850 num_stripes = 2;
1851 } else if (type & BTRFS_BLOCK_GROUP_RAID10) {
1852 min_stripes = 4;
1853 num_stripes = 4;
1854 }
1855
1856 if (type & BTRFS_BLOCK_GROUP_DUP)
1857 min_stripe_size = 2 * BTRFS_STRIPE_LEN;
1858 else
1859 min_stripe_size = BTRFS_STRIPE_LEN;
1860
1861 if (fs_info->alloc_start)
1862 mutex_lock(&fs_devices->device_list_mutex);
1863 rcu_read_lock();
1864 list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
1865 if (!device->in_fs_metadata || !device->bdev ||
1866 device->is_tgtdev_for_dev_replace)
1867 continue;
1868
1869 if (i >= nr_devices)
1870 break;
1871
1872 avail_space = device->total_bytes - device->bytes_used;
1873
1874 /* align with stripe_len */
1875 avail_space = div_u64(avail_space, BTRFS_STRIPE_LEN);
1876 avail_space *= BTRFS_STRIPE_LEN;
1877
1878 /*
1879 * In order to avoid overwritting the superblock on the drive,
1880 * btrfs starts at an offset of at least 1MB when doing chunk
1881 * allocation.
1882 */
1883 skip_space = 1024 * 1024;
1884
1885 /* user can set the offset in fs_info->alloc_start. */
1886 if (fs_info->alloc_start &&
1887 fs_info->alloc_start + BTRFS_STRIPE_LEN <=
1888 device->total_bytes) {
1889 rcu_read_unlock();
1890 skip_space = max(fs_info->alloc_start, skip_space);
1891
1892 /*
1893 * btrfs can not use the free space in
1894 * [0, skip_space - 1], we must subtract it from the
1895 * total. In order to implement it, we account the used
1896 * space in this range first.
1897 */
1898 ret = btrfs_account_dev_extents_size(device, 0,
1899 skip_space - 1,
1900 &used_space);
1901 if (ret) {
1902 kfree(devices_info);
1903 mutex_unlock(&fs_devices->device_list_mutex);
1904 return ret;
1905 }
1906
1907 rcu_read_lock();
1908
1909 /* calc the free space in [0, skip_space - 1] */
1910 skip_space -= used_space;
1911 }
1912
1913 /*
1914 * we can use the free space in [0, skip_space - 1], subtract
1915 * it from the total.
1916 */
1917 if (avail_space && avail_space >= skip_space)
1918 avail_space -= skip_space;
1919 else
1920 avail_space = 0;
1921
1922 if (avail_space < min_stripe_size)
1923 continue;
1924
1925 devices_info[i].dev = device;
1926 devices_info[i].max_avail = avail_space;
1927
1928 i++;
1929 }
1930 rcu_read_unlock();
1931 if (fs_info->alloc_start)
1932 mutex_unlock(&fs_devices->device_list_mutex);
1933
1934 nr_devices = i;
1935
1936 btrfs_descending_sort_devices(devices_info, nr_devices);
1937
1938 i = nr_devices - 1;
1939 avail_space = 0;
1940 while (nr_devices >= min_stripes) {
1941 if (num_stripes > nr_devices)
1942 num_stripes = nr_devices;
1943
1944 if (devices_info[i].max_avail >= min_stripe_size) {
1945 int j;
1946 u64 alloc_size;
1947
1948 avail_space += devices_info[i].max_avail * num_stripes;
1949 alloc_size = devices_info[i].max_avail;
1950 for (j = i + 1 - num_stripes; j <= i; j++)
1951 devices_info[j].max_avail -= alloc_size;
1952 }
1953 i--;
1954 nr_devices--;
1955 }
1956
1957 kfree(devices_info);
1958 *free_bytes = avail_space;
1959 return 0;
1960 }
1961
1962 /*
1963 * Calculate numbers for 'df', pessimistic in case of mixed raid profiles.
1964 *
1965 * If there's a redundant raid level at DATA block groups, use the respective
1966 * multiplier to scale the sizes.
1967 *
1968 * Unused device space usage is based on simulating the chunk allocator
1969 * algorithm that respects the device sizes, order of allocations and the
1970 * 'alloc_start' value, this is a close approximation of the actual use but
1971 * there are other factors that may change the result (like a new metadata
1972 * chunk).
1973 *
1974 * If metadata is exhausted, f_bavail will be 0.
1975 *
1976 * FIXME: not accurate for mixed block groups, total and free/used are ok,
1977 * available appears slightly larger.
1978 */
1979 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
1980 {
1981 struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
1982 struct btrfs_super_block *disk_super = fs_info->super_copy;
1983 struct list_head *head = &fs_info->space_info;
1984 struct btrfs_space_info *found;
1985 u64 total_used = 0;
1986 u64 total_free_data = 0;
1987 u64 total_free_meta = 0;
1988 int bits = dentry->d_sb->s_blocksize_bits;
1989 __be32 *fsid = (__be32 *)fs_info->fsid;
1990 unsigned factor = 1;
1991 struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
1992 int ret;
1993 u64 thresh = 0;
1994
1995 /*
1996 * holding chunk_muext to avoid allocating new chunks, holding
1997 * device_list_mutex to avoid the device being removed
1998 */
1999 rcu_read_lock();
2000 list_for_each_entry_rcu(found, head, list) {
2001 if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
2002 int i;
2003
2004 total_free_data += found->disk_total - found->disk_used;
2005 total_free_data -=
2006 btrfs_account_ro_block_groups_free_space(found);
2007
2008 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
2009 if (!list_empty(&found->block_groups[i])) {
2010 switch (i) {
2011 case BTRFS_RAID_DUP:
2012 case BTRFS_RAID_RAID1:
2013 case BTRFS_RAID_RAID10:
2014 factor = 2;
2015 }
2016 }
2017 }
2018 }
2019 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
2020 total_free_meta += found->disk_total - found->disk_used;
2021
2022 total_used += found->disk_used;
2023 }
2024
2025 rcu_read_unlock();
2026
2027 buf->f_blocks = div_u64(btrfs_super_total_bytes(disk_super), factor);
2028 buf->f_blocks >>= bits;
2029 buf->f_bfree = buf->f_blocks - (div_u64(total_used, factor) >> bits);
2030
2031 /* Account global block reserve as used, it's in logical size already */
2032 spin_lock(&block_rsv->lock);
2033 buf->f_bfree -= block_rsv->size >> bits;
2034 spin_unlock(&block_rsv->lock);
2035
2036 buf->f_bavail = div_u64(total_free_data, factor);
2037 ret = btrfs_calc_avail_data_space(fs_info->tree_root, &total_free_data);
2038 if (ret)
2039 return ret;
2040 buf->f_bavail += div_u64(total_free_data, factor);
2041 buf->f_bavail = buf->f_bavail >> bits;
2042
2043 /*
2044 * We calculate the remaining metadata space minus global reserve. If
2045 * this is (supposedly) smaller than zero, there's no space. But this
2046 * does not hold in practice, the exhausted state happens where's still
2047 * some positive delta. So we apply some guesswork and compare the
2048 * delta to a 4M threshold. (Practically observed delta was ~2M.)
2049 *
2050 * We probably cannot calculate the exact threshold value because this
2051 * depends on the internal reservations requested by various
2052 * operations, so some operations that consume a few metadata will
2053 * succeed even if the Avail is zero. But this is better than the other
2054 * way around.
2055 */
2056 thresh = 4 * 1024 * 1024;
2057
2058 if (total_free_meta - thresh < block_rsv->size)
2059 buf->f_bavail = 0;
2060
2061 buf->f_type = BTRFS_SUPER_MAGIC;
2062 buf->f_bsize = dentry->d_sb->s_blocksize;
2063 buf->f_namelen = BTRFS_NAME_LEN;
2064
2065 /* We treat it as constant endianness (it doesn't matter _which_)
2066 because we want the fsid to come out the same whether mounted
2067 on a big-endian or little-endian host */
2068 buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
2069 buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
2070 /* Mask in the root object ID too, to disambiguate subvols */
2071 buf->f_fsid.val[0] ^= BTRFS_I(d_inode(dentry))->root->objectid >> 32;
2072 buf->f_fsid.val[1] ^= BTRFS_I(d_inode(dentry))->root->objectid;
2073
2074 return 0;
2075 }
2076
2077 static void btrfs_kill_super(struct super_block *sb)
2078 {
2079 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2080 kill_anon_super(sb);
2081 free_fs_info(fs_info);
2082 }
2083
2084 static struct file_system_type btrfs_fs_type = {
2085 .owner = THIS_MODULE,
2086 .name = "btrfs",
2087 .mount = btrfs_mount,
2088 .kill_sb = btrfs_kill_super,
2089 .fs_flags = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,
2090 };
2091 MODULE_ALIAS_FS("btrfs");
2092
2093 static int btrfs_control_open(struct inode *inode, struct file *file)
2094 {
2095 /*
2096 * The control file's private_data is used to hold the
2097 * transaction when it is started and is used to keep
2098 * track of whether a transaction is already in progress.
2099 */
2100 file->private_data = NULL;
2101 return 0;
2102 }
2103
2104 /*
2105 * used by btrfsctl to scan devices when no FS is mounted
2106 */
2107 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
2108 unsigned long arg)
2109 {
2110 struct btrfs_ioctl_vol_args *vol;
2111 struct btrfs_fs_devices *fs_devices;
2112 int ret = -ENOTTY;
2113
2114 if (!capable(CAP_SYS_ADMIN))
2115 return -EPERM;
2116
2117 vol = memdup_user((void __user *)arg, sizeof(*vol));
2118 if (IS_ERR(vol))
2119 return PTR_ERR(vol);
2120
2121 switch (cmd) {
2122 case BTRFS_IOC_SCAN_DEV:
2123 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
2124 &btrfs_fs_type, &fs_devices);
2125 break;
2126 case BTRFS_IOC_DEVICES_READY:
2127 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
2128 &btrfs_fs_type, &fs_devices);
2129 if (ret)
2130 break;
2131 ret = !(fs_devices->num_devices == fs_devices->total_devices);
2132 break;
2133 }
2134
2135 kfree(vol);
2136 return ret;
2137 }
2138
2139 static int btrfs_freeze(struct super_block *sb)
2140 {
2141 struct btrfs_trans_handle *trans;
2142 struct btrfs_root *root = btrfs_sb(sb)->tree_root;
2143
2144 trans = btrfs_attach_transaction_barrier(root);
2145 if (IS_ERR(trans)) {
2146 /* no transaction, don't bother */
2147 if (PTR_ERR(trans) == -ENOENT)
2148 return 0;
2149 return PTR_ERR(trans);
2150 }
2151 return btrfs_commit_transaction(trans, root);
2152 }
2153
2154 static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
2155 {
2156 struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
2157 struct btrfs_fs_devices *cur_devices;
2158 struct btrfs_device *dev, *first_dev = NULL;
2159 struct list_head *head;
2160 struct rcu_string *name;
2161
2162 mutex_lock(&fs_info->fs_devices->device_list_mutex);
2163 cur_devices = fs_info->fs_devices;
2164 while (cur_devices) {
2165 head = &cur_devices->devices;
2166 list_for_each_entry(dev, head, dev_list) {
2167 if (dev->missing)
2168 continue;
2169 if (!dev->name)
2170 continue;
2171 if (!first_dev || dev->devid < first_dev->devid)
2172 first_dev = dev;
2173 }
2174 cur_devices = cur_devices->seed;
2175 }
2176
2177 if (first_dev) {
2178 rcu_read_lock();
2179 name = rcu_dereference(first_dev->name);
2180 seq_escape(m, name->str, " \t\n\\");
2181 rcu_read_unlock();
2182 } else {
2183 WARN_ON(1);
2184 }
2185 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2186 return 0;
2187 }
2188
2189 static const struct super_operations btrfs_super_ops = {
2190 .drop_inode = btrfs_drop_inode,
2191 .evict_inode = btrfs_evict_inode,
2192 .put_super = btrfs_put_super,
2193 .sync_fs = btrfs_sync_fs,
2194 .show_options = btrfs_show_options,
2195 .show_devname = btrfs_show_devname,
2196 .write_inode = btrfs_write_inode,
2197 .alloc_inode = btrfs_alloc_inode,
2198 .destroy_inode = btrfs_destroy_inode,
2199 .statfs = btrfs_statfs,
2200 .remount_fs = btrfs_remount,
2201 .freeze_fs = btrfs_freeze,
2202 };
2203
2204 static const struct file_operations btrfs_ctl_fops = {
2205 .open = btrfs_control_open,
2206 .unlocked_ioctl = btrfs_control_ioctl,
2207 .compat_ioctl = btrfs_control_ioctl,
2208 .owner = THIS_MODULE,
2209 .llseek = noop_llseek,
2210 };
2211
2212 static struct miscdevice btrfs_misc = {
2213 .minor = BTRFS_MINOR,
2214 .name = "btrfs-control",
2215 .fops = &btrfs_ctl_fops
2216 };
2217
2218 MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
2219 MODULE_ALIAS("devname:btrfs-control");
2220
2221 static int btrfs_interface_init(void)
2222 {
2223 return misc_register(&btrfs_misc);
2224 }
2225
2226 static void btrfs_interface_exit(void)
2227 {
2228 misc_deregister(&btrfs_misc);
2229 }
2230
2231 static void btrfs_print_info(void)
2232 {
2233 printk(KERN_INFO "Btrfs loaded"
2234 #ifdef CONFIG_BTRFS_DEBUG
2235 ", debug=on"
2236 #endif
2237 #ifdef CONFIG_BTRFS_ASSERT
2238 ", assert=on"
2239 #endif
2240 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
2241 ", integrity-checker=on"
2242 #endif
2243 "\n");
2244 }
2245
2246 static int btrfs_run_sanity_tests(void)
2247 {
2248 int ret;
2249
2250 ret = btrfs_init_test_fs();
2251 if (ret)
2252 return ret;
2253
2254 ret = btrfs_test_free_space_cache();
2255 if (ret)
2256 goto out;
2257 ret = btrfs_test_extent_buffer_operations();
2258 if (ret)
2259 goto out;
2260 ret = btrfs_test_extent_io();
2261 if (ret)
2262 goto out;
2263 ret = btrfs_test_inodes();
2264 if (ret)
2265 goto out;
2266 ret = btrfs_test_qgroups();
2267 out:
2268 btrfs_destroy_test_fs();
2269 return ret;
2270 }
2271
2272 static int __init init_btrfs_fs(void)
2273 {
2274 int err;
2275
2276 err = btrfs_hash_init();
2277 if (err)
2278 return err;
2279
2280 btrfs_props_init();
2281
2282 err = btrfs_init_sysfs();
2283 if (err)
2284 goto free_hash;
2285
2286 btrfs_init_compress();
2287
2288 err = btrfs_init_cachep();
2289 if (err)
2290 goto free_compress;
2291
2292 err = extent_io_init();
2293 if (err)
2294 goto free_cachep;
2295
2296 err = extent_map_init();
2297 if (err)
2298 goto free_extent_io;
2299
2300 err = ordered_data_init();
2301 if (err)
2302 goto free_extent_map;
2303
2304 err = btrfs_delayed_inode_init();
2305 if (err)
2306 goto free_ordered_data;
2307
2308 err = btrfs_auto_defrag_init();
2309 if (err)
2310 goto free_delayed_inode;
2311
2312 err = btrfs_delayed_ref_init();
2313 if (err)
2314 goto free_auto_defrag;
2315
2316 err = btrfs_prelim_ref_init();
2317 if (err)
2318 goto free_delayed_ref;
2319
2320 err = btrfs_end_io_wq_init();
2321 if (err)
2322 goto free_prelim_ref;
2323
2324 err = btrfs_interface_init();
2325 if (err)
2326 goto free_end_io_wq;
2327
2328 btrfs_init_lockdep();
2329
2330 btrfs_print_info();
2331
2332 err = btrfs_run_sanity_tests();
2333 if (err)
2334 goto unregister_ioctl;
2335
2336 err = register_filesystem(&btrfs_fs_type);
2337 if (err)
2338 goto unregister_ioctl;
2339
2340 return 0;
2341
2342 unregister_ioctl:
2343 btrfs_interface_exit();
2344 free_end_io_wq:
2345 btrfs_end_io_wq_exit();
2346 free_prelim_ref:
2347 btrfs_prelim_ref_exit();
2348 free_delayed_ref:
2349 btrfs_delayed_ref_exit();
2350 free_auto_defrag:
2351 btrfs_auto_defrag_exit();
2352 free_delayed_inode:
2353 btrfs_delayed_inode_exit();
2354 free_ordered_data:
2355 ordered_data_exit();
2356 free_extent_map:
2357 extent_map_exit();
2358 free_extent_io:
2359 extent_io_exit();
2360 free_cachep:
2361 btrfs_destroy_cachep();
2362 free_compress:
2363 btrfs_exit_compress();
2364 btrfs_exit_sysfs();
2365 free_hash:
2366 btrfs_hash_exit();
2367 return err;
2368 }
2369
2370 static void __exit exit_btrfs_fs(void)
2371 {
2372 btrfs_destroy_cachep();
2373 btrfs_delayed_ref_exit();
2374 btrfs_auto_defrag_exit();
2375 btrfs_delayed_inode_exit();
2376 btrfs_prelim_ref_exit();
2377 ordered_data_exit();
2378 extent_map_exit();
2379 extent_io_exit();
2380 btrfs_interface_exit();
2381 btrfs_end_io_wq_exit();
2382 unregister_filesystem(&btrfs_fs_type);
2383 btrfs_exit_sysfs();
2384 btrfs_cleanup_fs_uuids();
2385 btrfs_exit_compress();
2386 btrfs_hash_exit();
2387 }
2388
2389 late_initcall(init_btrfs_fs);
2390 module_exit(exit_btrfs_fs)
2391
2392 MODULE_LICENSE("GPL");
Linux kernel - Deliverables
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