1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (C) 2007 Oracle. All rights reserved.
6 #include <linux/blkdev.h>
7 #include <linux/module.h>
9 #include <linux/pagemap.h>
10 #include <linux/highmem.h>
11 #include <linux/time.h>
12 #include <linux/init.h>
13 #include <linux/seq_file.h>
14 #include <linux/string.h>
15 #include <linux/backing-dev.h>
16 #include <linux/mount.h>
17 #include <linux/writeback.h>
18 #include <linux/statfs.h>
19 #include <linux/compat.h>
20 #include <linux/parser.h>
21 #include <linux/ctype.h>
22 #include <linux/namei.h>
23 #include <linux/miscdevice.h>
24 #include <linux/magic.h>
25 #include <linux/slab.h>
26 #include <linux/ratelimit.h>
27 #include <linux/crc32c.h>
28 #include <linux/btrfs.h>
29 #include "delayed-inode.h"
32 #include "transaction.h"
33 #include "btrfs_inode.h"
34 #include "print-tree.h"
39 #include "compression.h"
40 #include "rcu-string.h"
41 #include "dev-replace.h"
42 #include "free-space-cache.h"
44 #include "space-info.h"
47 #include "tests/btrfs-tests.h"
48 #include "block-group.h"
52 #define CREATE_TRACE_POINTS
53 #include <trace/events/btrfs.h>
55 static const struct super_operations btrfs_super_ops;
58 * Types for mounting the default subvolume and a subvolume explicitly
59 * requested by subvol=/path. That way the callchain is straightforward and we
60 * don't have to play tricks with the mount options and recursive calls to
63 * The new btrfs_root_fs_type also servers as a tag for the bdev_holder.
65 static struct file_system_type btrfs_fs_type;
66 static struct file_system_type btrfs_root_fs_type;
68 static int btrfs_remount(struct super_block *sb, int *flags, char *data);
72 #define STATE_STRING_PREFACE ": state "
73 #define STATE_STRING_BUF_LEN (sizeof(STATE_STRING_PREFACE) + BTRFS_FS_STATE_COUNT)
76 * Characters to print to indicate error conditions or uncommon filesystem state.
79 static const char fs_state_chars[] = {
80 [BTRFS_FS_STATE_ERROR] = 'E',
81 [BTRFS_FS_STATE_REMOUNTING] = 'M',
82 [BTRFS_FS_STATE_RO] = 0,
83 [BTRFS_FS_STATE_TRANS_ABORTED] = 'A',
84 [BTRFS_FS_STATE_DEV_REPLACING] = 'R',
85 [BTRFS_FS_STATE_DUMMY_FS_INFO] = 0,
86 [BTRFS_FS_STATE_NO_CSUMS] = 'C',
87 [BTRFS_FS_STATE_LOG_CLEANUP_ERROR] = 'L',
90 static void btrfs_state_to_string(const struct btrfs_fs_info *info, char *buf)
93 bool states_printed = false;
94 unsigned long fs_state = READ_ONCE(info->fs_state);
97 memcpy(curr, STATE_STRING_PREFACE, sizeof(STATE_STRING_PREFACE));
98 curr += sizeof(STATE_STRING_PREFACE) - 1;
100 for_each_set_bit(bit, &fs_state, sizeof(fs_state)) {
101 WARN_ON_ONCE(bit >= BTRFS_FS_STATE_COUNT);
102 if ((bit < BTRFS_FS_STATE_COUNT) && fs_state_chars[bit]) {
103 *curr++ = fs_state_chars[bit];
104 states_printed = true;
108 /* If no states were printed, reset the buffer */
117 * Generally the error codes correspond to their respective errors, but there
118 * are a few special cases.
120 * EUCLEAN: Any sort of corruption that we encounter. The tree-checker for
121 * instance will return EUCLEAN if any of the blocks are corrupted in
122 * a way that is problematic. We want to reserve EUCLEAN for these
123 * sort of corruptions.
125 * EROFS: If we check BTRFS_FS_STATE_ERROR and fail out with a return error, we
126 * need to use EROFS for this case. We will have no idea of the
127 * original failure, that will have been reported at the time we tripped
128 * over the error. Each subsequent error that doesn't have any context
129 * of the original error should use EROFS when handling BTRFS_FS_STATE_ERROR.
131 const char * __attribute_const__ btrfs_decode_error(int errno)
133 char *errstr = "unknown";
136 case -ENOENT: /* -2 */
137 errstr = "No such entry";
140 errstr = "IO failure";
142 case -ENOMEM: /* -12*/
143 errstr = "Out of memory";
145 case -EEXIST: /* -17 */
146 errstr = "Object already exists";
148 case -ENOSPC: /* -28 */
149 errstr = "No space left";
151 case -EROFS: /* -30 */
152 errstr = "Readonly filesystem";
154 case -EOPNOTSUPP: /* -95 */
155 errstr = "Operation not supported";
157 case -EUCLEAN: /* -117 */
158 errstr = "Filesystem corrupted";
160 case -EDQUOT: /* -122 */
161 errstr = "Quota exceeded";
169 * __btrfs_handle_fs_error decodes expected errors from the caller and
170 * invokes the appropriate error response.
173 void __btrfs_handle_fs_error(struct btrfs_fs_info *fs_info, const char *function,
174 unsigned int line, int errno, const char *fmt, ...)
176 struct super_block *sb = fs_info->sb;
178 char statestr[STATE_STRING_BUF_LEN];
183 * Special case: if the error is EROFS, and we're already
184 * under SB_RDONLY, then it is safe here.
186 if (errno == -EROFS && sb_rdonly(sb))
190 errstr = btrfs_decode_error(errno);
191 btrfs_state_to_string(fs_info, statestr);
193 struct va_format vaf;
200 pr_crit("BTRFS: error (device %s%s) in %s:%d: errno=%d %s (%pV)\n",
201 sb->s_id, statestr, function, line, errno, errstr, &vaf);
204 pr_crit("BTRFS: error (device %s%s) in %s:%d: errno=%d %s\n",
205 sb->s_id, statestr, function, line, errno, errstr);
210 * Today we only save the error info to memory. Long term we'll
211 * also send it down to the disk
213 set_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state);
215 /* Don't go through full error handling during mount */
216 if (!(sb->s_flags & SB_BORN))
222 btrfs_discard_stop(fs_info);
224 /* btrfs handle error by forcing the filesystem readonly */
225 btrfs_set_sb_rdonly(sb);
226 btrfs_info(fs_info, "forced readonly");
228 * Note that a running device replace operation is not canceled here
229 * although there is no way to update the progress. It would add the
230 * risk of a deadlock, therefore the canceling is omitted. The only
231 * penalty is that some I/O remains active until the procedure
232 * completes. The next time when the filesystem is mounted writable
233 * again, the device replace operation continues.
238 static const char * const logtypes[] = {
251 * Use one ratelimit state per log level so that a flood of less important
252 * messages doesn't cause more important ones to be dropped.
254 static struct ratelimit_state printk_limits[] = {
255 RATELIMIT_STATE_INIT(printk_limits[0], DEFAULT_RATELIMIT_INTERVAL, 100),
256 RATELIMIT_STATE_INIT(printk_limits[1], DEFAULT_RATELIMIT_INTERVAL, 100),
257 RATELIMIT_STATE_INIT(printk_limits[2], DEFAULT_RATELIMIT_INTERVAL, 100),
258 RATELIMIT_STATE_INIT(printk_limits[3], DEFAULT_RATELIMIT_INTERVAL, 100),
259 RATELIMIT_STATE_INIT(printk_limits[4], DEFAULT_RATELIMIT_INTERVAL, 100),
260 RATELIMIT_STATE_INIT(printk_limits[5], DEFAULT_RATELIMIT_INTERVAL, 100),
261 RATELIMIT_STATE_INIT(printk_limits[6], DEFAULT_RATELIMIT_INTERVAL, 100),
262 RATELIMIT_STATE_INIT(printk_limits[7], DEFAULT_RATELIMIT_INTERVAL, 100),
265 void __cold _btrfs_printk(const struct btrfs_fs_info *fs_info, const char *fmt, ...)
267 char lvl[PRINTK_MAX_SINGLE_HEADER_LEN + 1] = "\0";
268 struct va_format vaf;
271 const char *type = logtypes[4];
272 struct ratelimit_state *ratelimit = &printk_limits[4];
276 while ((kern_level = printk_get_level(fmt)) != 0) {
277 size_t size = printk_skip_level(fmt) - fmt;
279 if (kern_level >= '0' && kern_level <= '7') {
280 memcpy(lvl, fmt, size);
282 type = logtypes[kern_level - '0'];
283 ratelimit = &printk_limits[kern_level - '0'];
291 if (__ratelimit(ratelimit)) {
293 char statestr[STATE_STRING_BUF_LEN];
295 btrfs_state_to_string(fs_info, statestr);
296 _printk("%sBTRFS %s (device %s%s): %pV\n", lvl, type,
297 fs_info->sb->s_id, statestr, &vaf);
299 _printk("%sBTRFS %s: %pV\n", lvl, type, &vaf);
307 #if BITS_PER_LONG == 32
308 void __cold btrfs_warn_32bit_limit(struct btrfs_fs_info *fs_info)
310 if (!test_and_set_bit(BTRFS_FS_32BIT_WARN, &fs_info->flags)) {
311 btrfs_warn(fs_info, "reaching 32bit limit for logical addresses");
313 "due to page cache limit on 32bit systems, btrfs can't access metadata at or beyond %lluT",
314 BTRFS_32BIT_MAX_FILE_SIZE >> 40);
316 "please consider upgrading to 64bit kernel/hardware");
320 void __cold btrfs_err_32bit_limit(struct btrfs_fs_info *fs_info)
322 if (!test_and_set_bit(BTRFS_FS_32BIT_ERROR, &fs_info->flags)) {
323 btrfs_err(fs_info, "reached 32bit limit for logical addresses");
325 "due to page cache limit on 32bit systems, metadata beyond %lluT can't be accessed",
326 BTRFS_32BIT_MAX_FILE_SIZE >> 40);
328 "please consider upgrading to 64bit kernel/hardware");
334 * We only mark the transaction aborted and then set the file system read-only.
335 * This will prevent new transactions from starting or trying to join this
338 * This means that error recovery at the call site is limited to freeing
339 * any local memory allocations and passing the error code up without
340 * further cleanup. The transaction should complete as it normally would
341 * in the call path but will return -EIO.
343 * We'll complete the cleanup in btrfs_end_transaction and
344 * btrfs_commit_transaction.
347 void __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
348 const char *function,
349 unsigned int line, int errno, bool first_hit)
351 struct btrfs_fs_info *fs_info = trans->fs_info;
353 WRITE_ONCE(trans->aborted, errno);
354 WRITE_ONCE(trans->transaction->aborted, errno);
355 if (first_hit && errno == -ENOSPC)
356 btrfs_dump_space_info_for_trans_abort(fs_info);
357 /* Wake up anybody who may be waiting on this transaction */
358 wake_up(&fs_info->transaction_wait);
359 wake_up(&fs_info->transaction_blocked_wait);
360 __btrfs_handle_fs_error(fs_info, function, line, errno, NULL);
363 * __btrfs_panic decodes unexpected, fatal errors from the caller,
364 * issues an alert, and either panics or BUGs, depending on mount options.
367 void __btrfs_panic(struct btrfs_fs_info *fs_info, const char *function,
368 unsigned int line, int errno, const char *fmt, ...)
370 char *s_id = "<unknown>";
372 struct va_format vaf = { .fmt = fmt };
376 s_id = fs_info->sb->s_id;
381 errstr = btrfs_decode_error(errno);
382 if (fs_info && (btrfs_test_opt(fs_info, PANIC_ON_FATAL_ERROR)))
383 panic(KERN_CRIT "BTRFS panic (device %s) in %s:%d: %pV (errno=%d %s)\n",
384 s_id, function, line, &vaf, errno, errstr);
386 btrfs_crit(fs_info, "panic in %s:%d: %pV (errno=%d %s)",
387 function, line, &vaf, errno, errstr);
389 /* Caller calls BUG() */
392 static void btrfs_put_super(struct super_block *sb)
394 close_ctree(btrfs_sb(sb));
403 Opt_compress_force_type,
408 Opt_flushoncommit, Opt_noflushoncommit,
410 Opt_barrier, Opt_nobarrier,
411 Opt_datacow, Opt_nodatacow,
412 Opt_datasum, Opt_nodatasum,
413 Opt_defrag, Opt_nodefrag,
414 Opt_discard, Opt_nodiscard,
418 Opt_rescan_uuid_tree,
420 Opt_space_cache, Opt_no_space_cache,
421 Opt_space_cache_version,
423 Opt_ssd_spread, Opt_nossd_spread,
428 Opt_treelog, Opt_notreelog,
429 Opt_user_subvol_rm_allowed,
439 /* Deprecated options */
441 Opt_inode_cache, Opt_noinode_cache,
443 /* Debugging options */
445 Opt_check_integrity_including_extent_data,
446 Opt_check_integrity_print_mask,
447 Opt_enospc_debug, Opt_noenospc_debug,
448 #ifdef CONFIG_BTRFS_DEBUG
449 Opt_fragment_data, Opt_fragment_metadata, Opt_fragment_all,
451 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
457 static const match_table_t tokens = {
459 {Opt_noacl, "noacl"},
460 {Opt_clear_cache, "clear_cache"},
461 {Opt_commit_interval, "commit=%u"},
462 {Opt_compress, "compress"},
463 {Opt_compress_type, "compress=%s"},
464 {Opt_compress_force, "compress-force"},
465 {Opt_compress_force_type, "compress-force=%s"},
466 {Opt_degraded, "degraded"},
467 {Opt_device, "device=%s"},
468 {Opt_fatal_errors, "fatal_errors=%s"},
469 {Opt_flushoncommit, "flushoncommit"},
470 {Opt_noflushoncommit, "noflushoncommit"},
471 {Opt_inode_cache, "inode_cache"},
472 {Opt_noinode_cache, "noinode_cache"},
473 {Opt_max_inline, "max_inline=%s"},
474 {Opt_barrier, "barrier"},
475 {Opt_nobarrier, "nobarrier"},
476 {Opt_datacow, "datacow"},
477 {Opt_nodatacow, "nodatacow"},
478 {Opt_datasum, "datasum"},
479 {Opt_nodatasum, "nodatasum"},
480 {Opt_defrag, "autodefrag"},
481 {Opt_nodefrag, "noautodefrag"},
482 {Opt_discard, "discard"},
483 {Opt_discard_mode, "discard=%s"},
484 {Opt_nodiscard, "nodiscard"},
485 {Opt_norecovery, "norecovery"},
486 {Opt_ratio, "metadata_ratio=%u"},
487 {Opt_rescan_uuid_tree, "rescan_uuid_tree"},
488 {Opt_skip_balance, "skip_balance"},
489 {Opt_space_cache, "space_cache"},
490 {Opt_no_space_cache, "nospace_cache"},
491 {Opt_space_cache_version, "space_cache=%s"},
493 {Opt_nossd, "nossd"},
494 {Opt_ssd_spread, "ssd_spread"},
495 {Opt_nossd_spread, "nossd_spread"},
496 {Opt_subvol, "subvol=%s"},
497 {Opt_subvol_empty, "subvol="},
498 {Opt_subvolid, "subvolid=%s"},
499 {Opt_thread_pool, "thread_pool=%u"},
500 {Opt_treelog, "treelog"},
501 {Opt_notreelog, "notreelog"},
502 {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
505 {Opt_rescue, "rescue=%s"},
506 /* Deprecated, with alias rescue=nologreplay */
507 {Opt_nologreplay, "nologreplay"},
508 /* Deprecated, with alias rescue=usebackuproot */
509 {Opt_usebackuproot, "usebackuproot"},
511 /* Deprecated options */
512 {Opt_recovery, "recovery"},
514 /* Debugging options */
515 {Opt_check_integrity, "check_int"},
516 {Opt_check_integrity_including_extent_data, "check_int_data"},
517 {Opt_check_integrity_print_mask, "check_int_print_mask=%u"},
518 {Opt_enospc_debug, "enospc_debug"},
519 {Opt_noenospc_debug, "noenospc_debug"},
520 #ifdef CONFIG_BTRFS_DEBUG
521 {Opt_fragment_data, "fragment=data"},
522 {Opt_fragment_metadata, "fragment=metadata"},
523 {Opt_fragment_all, "fragment=all"},
525 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
526 {Opt_ref_verify, "ref_verify"},
531 static const match_table_t rescue_tokens = {
532 {Opt_usebackuproot, "usebackuproot"},
533 {Opt_nologreplay, "nologreplay"},
534 {Opt_ignorebadroots, "ignorebadroots"},
535 {Opt_ignorebadroots, "ibadroots"},
536 {Opt_ignoredatacsums, "ignoredatacsums"},
537 {Opt_ignoredatacsums, "idatacsums"},
538 {Opt_rescue_all, "all"},
542 static bool check_ro_option(struct btrfs_fs_info *fs_info, unsigned long opt,
543 const char *opt_name)
545 if (fs_info->mount_opt & opt) {
546 btrfs_err(fs_info, "%s must be used with ro mount option",
553 static int parse_rescue_options(struct btrfs_fs_info *info, const char *options)
558 substring_t args[MAX_OPT_ARGS];
561 opts = kstrdup(options, GFP_KERNEL);
566 while ((p = strsep(&opts, ":")) != NULL) {
571 token = match_token(p, rescue_tokens, args);
573 case Opt_usebackuproot:
575 "trying to use backup root at mount time");
576 btrfs_set_opt(info->mount_opt, USEBACKUPROOT);
578 case Opt_nologreplay:
579 btrfs_set_and_info(info, NOLOGREPLAY,
580 "disabling log replay at mount time");
582 case Opt_ignorebadroots:
583 btrfs_set_and_info(info, IGNOREBADROOTS,
584 "ignoring bad roots");
586 case Opt_ignoredatacsums:
587 btrfs_set_and_info(info, IGNOREDATACSUMS,
588 "ignoring data csums");
591 btrfs_info(info, "enabling all of the rescue options");
592 btrfs_set_and_info(info, IGNOREDATACSUMS,
593 "ignoring data csums");
594 btrfs_set_and_info(info, IGNOREBADROOTS,
595 "ignoring bad roots");
596 btrfs_set_and_info(info, NOLOGREPLAY,
597 "disabling log replay at mount time");
600 btrfs_info(info, "unrecognized rescue option '%s'", p);
614 * Regular mount options parser. Everything that is needed only when
615 * reading in a new superblock is parsed here.
616 * XXX JDM: This needs to be cleaned up for remount.
618 int btrfs_parse_options(struct btrfs_fs_info *info, char *options,
619 unsigned long new_flags)
621 substring_t args[MAX_OPT_ARGS];
626 bool compress_force = false;
627 enum btrfs_compression_type saved_compress_type;
628 int saved_compress_level;
629 bool saved_compress_force;
631 const bool remounting = test_bit(BTRFS_FS_STATE_REMOUNTING, &info->fs_state);
633 if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE))
634 btrfs_set_opt(info->mount_opt, FREE_SPACE_TREE);
635 else if (btrfs_free_space_cache_v1_active(info)) {
636 if (btrfs_is_zoned(info)) {
638 "zoned: clearing existing space cache");
639 btrfs_set_super_cache_generation(info->super_copy, 0);
641 btrfs_set_opt(info->mount_opt, SPACE_CACHE);
646 * Even the options are empty, we still need to do extra check
652 while ((p = strsep(&options, ",")) != NULL) {
657 token = match_token(p, tokens, args);
660 btrfs_info(info, "allowing degraded mounts");
661 btrfs_set_opt(info->mount_opt, DEGRADED);
664 case Opt_subvol_empty:
668 * These are parsed by btrfs_parse_subvol_options or
669 * btrfs_parse_device_options and can be ignored here.
673 btrfs_set_and_info(info, NODATASUM,
674 "setting nodatasum");
677 if (btrfs_test_opt(info, NODATASUM)) {
678 if (btrfs_test_opt(info, NODATACOW))
680 "setting datasum, datacow enabled");
682 btrfs_info(info, "setting datasum");
684 btrfs_clear_opt(info->mount_opt, NODATACOW);
685 btrfs_clear_opt(info->mount_opt, NODATASUM);
688 if (!btrfs_test_opt(info, NODATACOW)) {
689 if (!btrfs_test_opt(info, COMPRESS) ||
690 !btrfs_test_opt(info, FORCE_COMPRESS)) {
692 "setting nodatacow, compression disabled");
694 btrfs_info(info, "setting nodatacow");
697 btrfs_clear_opt(info->mount_opt, COMPRESS);
698 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
699 btrfs_set_opt(info->mount_opt, NODATACOW);
700 btrfs_set_opt(info->mount_opt, NODATASUM);
703 btrfs_clear_and_info(info, NODATACOW,
706 case Opt_compress_force:
707 case Opt_compress_force_type:
708 compress_force = true;
711 case Opt_compress_type:
712 saved_compress_type = btrfs_test_opt(info,
714 info->compress_type : BTRFS_COMPRESS_NONE;
715 saved_compress_force =
716 btrfs_test_opt(info, FORCE_COMPRESS);
717 saved_compress_level = info->compress_level;
718 if (token == Opt_compress ||
719 token == Opt_compress_force ||
720 strncmp(args[0].from, "zlib", 4) == 0) {
721 compress_type = "zlib";
723 info->compress_type = BTRFS_COMPRESS_ZLIB;
724 info->compress_level = BTRFS_ZLIB_DEFAULT_LEVEL;
726 * args[0] contains uninitialized data since
727 * for these tokens we don't expect any
730 if (token != Opt_compress &&
731 token != Opt_compress_force)
732 info->compress_level =
733 btrfs_compress_str2level(
736 btrfs_set_opt(info->mount_opt, COMPRESS);
737 btrfs_clear_opt(info->mount_opt, NODATACOW);
738 btrfs_clear_opt(info->mount_opt, NODATASUM);
740 } else if (strncmp(args[0].from, "lzo", 3) == 0) {
741 compress_type = "lzo";
742 info->compress_type = BTRFS_COMPRESS_LZO;
743 info->compress_level = 0;
744 btrfs_set_opt(info->mount_opt, COMPRESS);
745 btrfs_clear_opt(info->mount_opt, NODATACOW);
746 btrfs_clear_opt(info->mount_opt, NODATASUM);
747 btrfs_set_fs_incompat(info, COMPRESS_LZO);
749 } else if (strncmp(args[0].from, "zstd", 4) == 0) {
750 compress_type = "zstd";
751 info->compress_type = BTRFS_COMPRESS_ZSTD;
752 info->compress_level =
753 btrfs_compress_str2level(
756 btrfs_set_opt(info->mount_opt, COMPRESS);
757 btrfs_clear_opt(info->mount_opt, NODATACOW);
758 btrfs_clear_opt(info->mount_opt, NODATASUM);
759 btrfs_set_fs_incompat(info, COMPRESS_ZSTD);
761 } else if (strncmp(args[0].from, "no", 2) == 0) {
762 compress_type = "no";
763 info->compress_level = 0;
764 info->compress_type = 0;
765 btrfs_clear_opt(info->mount_opt, COMPRESS);
766 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
767 compress_force = false;
770 btrfs_err(info, "unrecognized compression value %s",
776 if (compress_force) {
777 btrfs_set_opt(info->mount_opt, FORCE_COMPRESS);
780 * If we remount from compress-force=xxx to
781 * compress=xxx, we need clear FORCE_COMPRESS
782 * flag, otherwise, there is no way for users
783 * to disable forcible compression separately.
785 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
787 if (no_compress == 1) {
788 btrfs_info(info, "use no compression");
789 } else if ((info->compress_type != saved_compress_type) ||
790 (compress_force != saved_compress_force) ||
791 (info->compress_level != saved_compress_level)) {
792 btrfs_info(info, "%s %s compression, level %d",
793 (compress_force) ? "force" : "use",
794 compress_type, info->compress_level);
796 compress_force = false;
799 btrfs_set_and_info(info, SSD,
800 "enabling ssd optimizations");
801 btrfs_clear_opt(info->mount_opt, NOSSD);
804 btrfs_set_and_info(info, SSD,
805 "enabling ssd optimizations");
806 btrfs_set_and_info(info, SSD_SPREAD,
807 "using spread ssd allocation scheme");
808 btrfs_clear_opt(info->mount_opt, NOSSD);
811 btrfs_set_opt(info->mount_opt, NOSSD);
812 btrfs_clear_and_info(info, SSD,
813 "not using ssd optimizations");
815 case Opt_nossd_spread:
816 btrfs_clear_and_info(info, SSD_SPREAD,
817 "not using spread ssd allocation scheme");
820 btrfs_clear_and_info(info, NOBARRIER,
821 "turning on barriers");
824 btrfs_set_and_info(info, NOBARRIER,
825 "turning off barriers");
827 case Opt_thread_pool:
828 ret = match_int(&args[0], &intarg);
830 btrfs_err(info, "unrecognized thread_pool value %s",
833 } else if (intarg == 0) {
834 btrfs_err(info, "invalid value 0 for thread_pool");
838 info->thread_pool_size = intarg;
841 num = match_strdup(&args[0]);
843 info->max_inline = memparse(num, NULL);
846 if (info->max_inline) {
847 info->max_inline = min_t(u64,
851 btrfs_info(info, "max_inline at %llu",
859 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
860 info->sb->s_flags |= SB_POSIXACL;
863 btrfs_err(info, "support for ACL not compiled in!");
868 info->sb->s_flags &= ~SB_POSIXACL;
871 btrfs_set_and_info(info, NOTREELOG,
872 "disabling tree log");
875 btrfs_clear_and_info(info, NOTREELOG,
876 "enabling tree log");
879 case Opt_nologreplay:
881 "'nologreplay' is deprecated, use 'rescue=nologreplay' instead");
882 btrfs_set_and_info(info, NOLOGREPLAY,
883 "disabling log replay at mount time");
885 case Opt_flushoncommit:
886 btrfs_set_and_info(info, FLUSHONCOMMIT,
887 "turning on flush-on-commit");
889 case Opt_noflushoncommit:
890 btrfs_clear_and_info(info, FLUSHONCOMMIT,
891 "turning off flush-on-commit");
894 ret = match_int(&args[0], &intarg);
896 btrfs_err(info, "unrecognized metadata_ratio value %s",
900 info->metadata_ratio = intarg;
901 btrfs_info(info, "metadata ratio %u",
902 info->metadata_ratio);
905 case Opt_discard_mode:
906 if (token == Opt_discard ||
907 strcmp(args[0].from, "sync") == 0) {
908 btrfs_clear_opt(info->mount_opt, DISCARD_ASYNC);
909 btrfs_set_and_info(info, DISCARD_SYNC,
910 "turning on sync discard");
911 } else if (strcmp(args[0].from, "async") == 0) {
912 btrfs_clear_opt(info->mount_opt, DISCARD_SYNC);
913 btrfs_set_and_info(info, DISCARD_ASYNC,
914 "turning on async discard");
916 btrfs_err(info, "unrecognized discard mode value %s",
923 btrfs_clear_and_info(info, DISCARD_SYNC,
924 "turning off discard");
925 btrfs_clear_and_info(info, DISCARD_ASYNC,
926 "turning off async discard");
928 case Opt_space_cache:
929 case Opt_space_cache_version:
931 * We already set FREE_SPACE_TREE above because we have
932 * compat_ro(FREE_SPACE_TREE) set, and we aren't going
933 * to allow v1 to be set for extent tree v2, simply
934 * ignore this setting if we're extent tree v2.
936 if (btrfs_fs_incompat(info, EXTENT_TREE_V2))
938 if (token == Opt_space_cache ||
939 strcmp(args[0].from, "v1") == 0) {
940 btrfs_clear_opt(info->mount_opt,
942 btrfs_set_and_info(info, SPACE_CACHE,
943 "enabling disk space caching");
944 } else if (strcmp(args[0].from, "v2") == 0) {
945 btrfs_clear_opt(info->mount_opt,
947 btrfs_set_and_info(info, FREE_SPACE_TREE,
948 "enabling free space tree");
950 btrfs_err(info, "unrecognized space_cache value %s",
956 case Opt_rescan_uuid_tree:
957 btrfs_set_opt(info->mount_opt, RESCAN_UUID_TREE);
959 case Opt_no_space_cache:
961 * We cannot operate without the free space tree with
962 * extent tree v2, ignore this option.
964 if (btrfs_fs_incompat(info, EXTENT_TREE_V2))
966 if (btrfs_test_opt(info, SPACE_CACHE)) {
967 btrfs_clear_and_info(info, SPACE_CACHE,
968 "disabling disk space caching");
970 if (btrfs_test_opt(info, FREE_SPACE_TREE)) {
971 btrfs_clear_and_info(info, FREE_SPACE_TREE,
972 "disabling free space tree");
975 case Opt_inode_cache:
976 case Opt_noinode_cache:
978 "the 'inode_cache' option is deprecated and has no effect since 5.11");
980 case Opt_clear_cache:
982 * We cannot clear the free space tree with extent tree
983 * v2, ignore this option.
985 if (btrfs_fs_incompat(info, EXTENT_TREE_V2))
987 btrfs_set_and_info(info, CLEAR_CACHE,
988 "force clearing of disk cache");
990 case Opt_user_subvol_rm_allowed:
991 btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
993 case Opt_enospc_debug:
994 btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
996 case Opt_noenospc_debug:
997 btrfs_clear_opt(info->mount_opt, ENOSPC_DEBUG);
1000 btrfs_set_and_info(info, AUTO_DEFRAG,
1001 "enabling auto defrag");
1004 btrfs_clear_and_info(info, AUTO_DEFRAG,
1005 "disabling auto defrag");
1008 case Opt_usebackuproot:
1010 "'%s' is deprecated, use 'rescue=usebackuproot' instead",
1011 token == Opt_recovery ? "recovery" :
1014 "trying to use backup root at mount time");
1015 btrfs_set_opt(info->mount_opt, USEBACKUPROOT);
1017 case Opt_skip_balance:
1018 btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
1020 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
1021 case Opt_check_integrity_including_extent_data:
1023 "enabling check integrity including extent data");
1024 btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY_DATA);
1025 btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
1027 case Opt_check_integrity:
1028 btrfs_info(info, "enabling check integrity");
1029 btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
1031 case Opt_check_integrity_print_mask:
1032 ret = match_int(&args[0], &intarg);
1035 "unrecognized check_integrity_print_mask value %s",
1039 info->check_integrity_print_mask = intarg;
1040 btrfs_info(info, "check_integrity_print_mask 0x%x",
1041 info->check_integrity_print_mask);
1044 case Opt_check_integrity_including_extent_data:
1045 case Opt_check_integrity:
1046 case Opt_check_integrity_print_mask:
1048 "support for check_integrity* not compiled in!");
1052 case Opt_fatal_errors:
1053 if (strcmp(args[0].from, "panic") == 0) {
1054 btrfs_set_opt(info->mount_opt,
1055 PANIC_ON_FATAL_ERROR);
1056 } else if (strcmp(args[0].from, "bug") == 0) {
1057 btrfs_clear_opt(info->mount_opt,
1058 PANIC_ON_FATAL_ERROR);
1060 btrfs_err(info, "unrecognized fatal_errors value %s",
1066 case Opt_commit_interval:
1068 ret = match_int(&args[0], &intarg);
1070 btrfs_err(info, "unrecognized commit_interval value %s",
1077 "using default commit interval %us",
1078 BTRFS_DEFAULT_COMMIT_INTERVAL);
1079 intarg = BTRFS_DEFAULT_COMMIT_INTERVAL;
1080 } else if (intarg > 300) {
1081 btrfs_warn(info, "excessive commit interval %d",
1084 info->commit_interval = intarg;
1087 ret = parse_rescue_options(info, args[0].from);
1089 btrfs_err(info, "unrecognized rescue value %s",
1094 #ifdef CONFIG_BTRFS_DEBUG
1095 case Opt_fragment_all:
1096 btrfs_info(info, "fragmenting all space");
1097 btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
1098 btrfs_set_opt(info->mount_opt, FRAGMENT_METADATA);
1100 case Opt_fragment_metadata:
1101 btrfs_info(info, "fragmenting metadata");
1102 btrfs_set_opt(info->mount_opt,
1105 case Opt_fragment_data:
1106 btrfs_info(info, "fragmenting data");
1107 btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
1110 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
1111 case Opt_ref_verify:
1112 btrfs_info(info, "doing ref verification");
1113 btrfs_set_opt(info->mount_opt, REF_VERIFY);
1117 btrfs_err(info, "unrecognized mount option '%s'", p);
1125 /* We're read-only, don't have to check. */
1126 if (new_flags & SB_RDONLY)
1129 if (check_ro_option(info, BTRFS_MOUNT_NOLOGREPLAY, "nologreplay") ||
1130 check_ro_option(info, BTRFS_MOUNT_IGNOREBADROOTS, "ignorebadroots") ||
1131 check_ro_option(info, BTRFS_MOUNT_IGNOREDATACSUMS, "ignoredatacsums"))
1134 if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE) &&
1135 !btrfs_test_opt(info, FREE_SPACE_TREE) &&
1136 !btrfs_test_opt(info, CLEAR_CACHE)) {
1137 btrfs_err(info, "cannot disable free space tree");
1140 if (btrfs_fs_compat_ro(info, BLOCK_GROUP_TREE) &&
1141 !btrfs_test_opt(info, FREE_SPACE_TREE)) {
1142 btrfs_err(info, "cannot disable free space tree with block-group-tree feature");
1146 ret = btrfs_check_mountopts_zoned(info);
1147 if (!ret && !remounting) {
1148 if (btrfs_test_opt(info, SPACE_CACHE))
1149 btrfs_info(info, "disk space caching is enabled");
1150 if (btrfs_test_opt(info, FREE_SPACE_TREE))
1151 btrfs_info(info, "using free space tree");
1157 * Parse mount options that are required early in the mount process.
1159 * All other options will be parsed on much later in the mount process and
1160 * only when we need to allocate a new super block.
1162 static int btrfs_parse_device_options(const char *options, fmode_t flags,
1165 substring_t args[MAX_OPT_ARGS];
1166 char *device_name, *opts, *orig, *p;
1167 struct btrfs_device *device = NULL;
1170 lockdep_assert_held(&uuid_mutex);
1176 * strsep changes the string, duplicate it because btrfs_parse_options
1179 opts = kstrdup(options, GFP_KERNEL);
1184 while ((p = strsep(&opts, ",")) != NULL) {
1190 token = match_token(p, tokens, args);
1191 if (token == Opt_device) {
1192 device_name = match_strdup(&args[0]);
1197 device = btrfs_scan_one_device(device_name, flags,
1200 if (IS_ERR(device)) {
1201 error = PTR_ERR(device);
1213 * Parse mount options that are related to subvolume id
1215 * The value is later passed to mount_subvol()
1217 static int btrfs_parse_subvol_options(const char *options, char **subvol_name,
1218 u64 *subvol_objectid)
1220 substring_t args[MAX_OPT_ARGS];
1221 char *opts, *orig, *p;
1229 * strsep changes the string, duplicate it because
1230 * btrfs_parse_device_options gets called later
1232 opts = kstrdup(options, GFP_KERNEL);
1237 while ((p = strsep(&opts, ",")) != NULL) {
1242 token = match_token(p, tokens, args);
1245 kfree(*subvol_name);
1246 *subvol_name = match_strdup(&args[0]);
1247 if (!*subvol_name) {
1253 error = match_u64(&args[0], &subvolid);
1257 /* we want the original fs_tree */
1259 subvolid = BTRFS_FS_TREE_OBJECTID;
1261 *subvol_objectid = subvolid;
1273 char *btrfs_get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
1274 u64 subvol_objectid)
1276 struct btrfs_root *root = fs_info->tree_root;
1277 struct btrfs_root *fs_root = NULL;
1278 struct btrfs_root_ref *root_ref;
1279 struct btrfs_inode_ref *inode_ref;
1280 struct btrfs_key key;
1281 struct btrfs_path *path = NULL;
1282 char *name = NULL, *ptr;
1287 path = btrfs_alloc_path();
1293 name = kmalloc(PATH_MAX, GFP_KERNEL);
1298 ptr = name + PATH_MAX - 1;
1302 * Walk up the subvolume trees in the tree of tree roots by root
1303 * backrefs until we hit the top-level subvolume.
1305 while (subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
1306 key.objectid = subvol_objectid;
1307 key.type = BTRFS_ROOT_BACKREF_KEY;
1308 key.offset = (u64)-1;
1310 ret = btrfs_search_backwards(root, &key, path);
1313 } else if (ret > 0) {
1318 subvol_objectid = key.offset;
1320 root_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
1321 struct btrfs_root_ref);
1322 len = btrfs_root_ref_name_len(path->nodes[0], root_ref);
1325 ret = -ENAMETOOLONG;
1328 read_extent_buffer(path->nodes[0], ptr + 1,
1329 (unsigned long)(root_ref + 1), len);
1331 dirid = btrfs_root_ref_dirid(path->nodes[0], root_ref);
1332 btrfs_release_path(path);
1334 fs_root = btrfs_get_fs_root(fs_info, subvol_objectid, true);
1335 if (IS_ERR(fs_root)) {
1336 ret = PTR_ERR(fs_root);
1342 * Walk up the filesystem tree by inode refs until we hit the
1345 while (dirid != BTRFS_FIRST_FREE_OBJECTID) {
1346 key.objectid = dirid;
1347 key.type = BTRFS_INODE_REF_KEY;
1348 key.offset = (u64)-1;
1350 ret = btrfs_search_backwards(fs_root, &key, path);
1353 } else if (ret > 0) {
1360 inode_ref = btrfs_item_ptr(path->nodes[0],
1362 struct btrfs_inode_ref);
1363 len = btrfs_inode_ref_name_len(path->nodes[0],
1367 ret = -ENAMETOOLONG;
1370 read_extent_buffer(path->nodes[0], ptr + 1,
1371 (unsigned long)(inode_ref + 1), len);
1373 btrfs_release_path(path);
1375 btrfs_put_root(fs_root);
1379 btrfs_free_path(path);
1380 if (ptr == name + PATH_MAX - 1) {
1384 memmove(name, ptr, name + PATH_MAX - ptr);
1389 btrfs_put_root(fs_root);
1390 btrfs_free_path(path);
1392 return ERR_PTR(ret);
1395 static int get_default_subvol_objectid(struct btrfs_fs_info *fs_info, u64 *objectid)
1397 struct btrfs_root *root = fs_info->tree_root;
1398 struct btrfs_dir_item *di;
1399 struct btrfs_path *path;
1400 struct btrfs_key location;
1403 path = btrfs_alloc_path();
1408 * Find the "default" dir item which points to the root item that we
1409 * will mount by default if we haven't been given a specific subvolume
1412 dir_id = btrfs_super_root_dir(fs_info->super_copy);
1413 di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
1415 btrfs_free_path(path);
1420 * Ok the default dir item isn't there. This is weird since
1421 * it's always been there, but don't freak out, just try and
1422 * mount the top-level subvolume.
1424 btrfs_free_path(path);
1425 *objectid = BTRFS_FS_TREE_OBJECTID;
1429 btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
1430 btrfs_free_path(path);
1431 *objectid = location.objectid;
1435 static int btrfs_fill_super(struct super_block *sb,
1436 struct btrfs_fs_devices *fs_devices,
1439 struct inode *inode;
1440 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1443 sb->s_maxbytes = MAX_LFS_FILESIZE;
1444 sb->s_magic = BTRFS_SUPER_MAGIC;
1445 sb->s_op = &btrfs_super_ops;
1446 sb->s_d_op = &btrfs_dentry_operations;
1447 sb->s_export_op = &btrfs_export_ops;
1448 #ifdef CONFIG_FS_VERITY
1449 sb->s_vop = &btrfs_verityops;
1451 sb->s_xattr = btrfs_xattr_handlers;
1452 sb->s_time_gran = 1;
1453 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
1454 sb->s_flags |= SB_POSIXACL;
1456 sb->s_flags |= SB_I_VERSION;
1457 sb->s_iflags |= SB_I_CGROUPWB;
1459 err = super_setup_bdi(sb);
1461 btrfs_err(fs_info, "super_setup_bdi failed");
1465 err = open_ctree(sb, fs_devices, (char *)data);
1467 btrfs_err(fs_info, "open_ctree failed");
1471 inode = btrfs_iget(sb, BTRFS_FIRST_FREE_OBJECTID, fs_info->fs_root);
1472 if (IS_ERR(inode)) {
1473 err = PTR_ERR(inode);
1477 sb->s_root = d_make_root(inode);
1483 sb->s_flags |= SB_ACTIVE;
1487 close_ctree(fs_info);
1491 int btrfs_sync_fs(struct super_block *sb, int wait)
1493 struct btrfs_trans_handle *trans;
1494 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1495 struct btrfs_root *root = fs_info->tree_root;
1497 trace_btrfs_sync_fs(fs_info, wait);
1500 filemap_flush(fs_info->btree_inode->i_mapping);
1504 btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
1506 trans = btrfs_attach_transaction_barrier(root);
1507 if (IS_ERR(trans)) {
1508 /* no transaction, don't bother */
1509 if (PTR_ERR(trans) == -ENOENT) {
1511 * Exit unless we have some pending changes
1512 * that need to go through commit
1514 if (fs_info->pending_changes == 0)
1517 * A non-blocking test if the fs is frozen. We must not
1518 * start a new transaction here otherwise a deadlock
1519 * happens. The pending operations are delayed to the
1520 * next commit after thawing.
1522 if (sb_start_write_trylock(sb))
1526 trans = btrfs_start_transaction(root, 0);
1529 return PTR_ERR(trans);
1531 return btrfs_commit_transaction(trans);
1534 static void print_rescue_option(struct seq_file *seq, const char *s, bool *printed)
1536 seq_printf(seq, "%s%s", (*printed) ? ":" : ",rescue=", s);
1540 static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
1542 struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
1543 const char *compress_type;
1544 const char *subvol_name;
1545 bool printed = false;
1547 if (btrfs_test_opt(info, DEGRADED))
1548 seq_puts(seq, ",degraded");
1549 if (btrfs_test_opt(info, NODATASUM))
1550 seq_puts(seq, ",nodatasum");
1551 if (btrfs_test_opt(info, NODATACOW))
1552 seq_puts(seq, ",nodatacow");
1553 if (btrfs_test_opt(info, NOBARRIER))
1554 seq_puts(seq, ",nobarrier");
1555 if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE)
1556 seq_printf(seq, ",max_inline=%llu", info->max_inline);
1557 if (info->thread_pool_size != min_t(unsigned long,
1558 num_online_cpus() + 2, 8))
1559 seq_printf(seq, ",thread_pool=%u", info->thread_pool_size);
1560 if (btrfs_test_opt(info, COMPRESS)) {
1561 compress_type = btrfs_compress_type2str(info->compress_type);
1562 if (btrfs_test_opt(info, FORCE_COMPRESS))
1563 seq_printf(seq, ",compress-force=%s", compress_type);
1565 seq_printf(seq, ",compress=%s", compress_type);
1566 if (info->compress_level)
1567 seq_printf(seq, ":%d", info->compress_level);
1569 if (btrfs_test_opt(info, NOSSD))
1570 seq_puts(seq, ",nossd");
1571 if (btrfs_test_opt(info, SSD_SPREAD))
1572 seq_puts(seq, ",ssd_spread");
1573 else if (btrfs_test_opt(info, SSD))
1574 seq_puts(seq, ",ssd");
1575 if (btrfs_test_opt(info, NOTREELOG))
1576 seq_puts(seq, ",notreelog");
1577 if (btrfs_test_opt(info, NOLOGREPLAY))
1578 print_rescue_option(seq, "nologreplay", &printed);
1579 if (btrfs_test_opt(info, USEBACKUPROOT))
1580 print_rescue_option(seq, "usebackuproot", &printed);
1581 if (btrfs_test_opt(info, IGNOREBADROOTS))
1582 print_rescue_option(seq, "ignorebadroots", &printed);
1583 if (btrfs_test_opt(info, IGNOREDATACSUMS))
1584 print_rescue_option(seq, "ignoredatacsums", &printed);
1585 if (btrfs_test_opt(info, FLUSHONCOMMIT))
1586 seq_puts(seq, ",flushoncommit");
1587 if (btrfs_test_opt(info, DISCARD_SYNC))
1588 seq_puts(seq, ",discard");
1589 if (btrfs_test_opt(info, DISCARD_ASYNC))
1590 seq_puts(seq, ",discard=async");
1591 if (!(info->sb->s_flags & SB_POSIXACL))
1592 seq_puts(seq, ",noacl");
1593 if (btrfs_free_space_cache_v1_active(info))
1594 seq_puts(seq, ",space_cache");
1595 else if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE))
1596 seq_puts(seq, ",space_cache=v2");
1598 seq_puts(seq, ",nospace_cache");
1599 if (btrfs_test_opt(info, RESCAN_UUID_TREE))
1600 seq_puts(seq, ",rescan_uuid_tree");
1601 if (btrfs_test_opt(info, CLEAR_CACHE))
1602 seq_puts(seq, ",clear_cache");
1603 if (btrfs_test_opt(info, USER_SUBVOL_RM_ALLOWED))
1604 seq_puts(seq, ",user_subvol_rm_allowed");
1605 if (btrfs_test_opt(info, ENOSPC_DEBUG))
1606 seq_puts(seq, ",enospc_debug");
1607 if (btrfs_test_opt(info, AUTO_DEFRAG))
1608 seq_puts(seq, ",autodefrag");
1609 if (btrfs_test_opt(info, SKIP_BALANCE))
1610 seq_puts(seq, ",skip_balance");
1611 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
1612 if (btrfs_test_opt(info, CHECK_INTEGRITY_DATA))
1613 seq_puts(seq, ",check_int_data");
1614 else if (btrfs_test_opt(info, CHECK_INTEGRITY))
1615 seq_puts(seq, ",check_int");
1616 if (info->check_integrity_print_mask)
1617 seq_printf(seq, ",check_int_print_mask=%d",
1618 info->check_integrity_print_mask);
1620 if (info->metadata_ratio)
1621 seq_printf(seq, ",metadata_ratio=%u", info->metadata_ratio);
1622 if (btrfs_test_opt(info, PANIC_ON_FATAL_ERROR))
1623 seq_puts(seq, ",fatal_errors=panic");
1624 if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL)
1625 seq_printf(seq, ",commit=%u", info->commit_interval);
1626 #ifdef CONFIG_BTRFS_DEBUG
1627 if (btrfs_test_opt(info, FRAGMENT_DATA))
1628 seq_puts(seq, ",fragment=data");
1629 if (btrfs_test_opt(info, FRAGMENT_METADATA))
1630 seq_puts(seq, ",fragment=metadata");
1632 if (btrfs_test_opt(info, REF_VERIFY))
1633 seq_puts(seq, ",ref_verify");
1634 seq_printf(seq, ",subvolid=%llu",
1635 BTRFS_I(d_inode(dentry))->root->root_key.objectid);
1636 subvol_name = btrfs_get_subvol_name_from_objectid(info,
1637 BTRFS_I(d_inode(dentry))->root->root_key.objectid);
1638 if (!IS_ERR(subvol_name)) {
1639 seq_puts(seq, ",subvol=");
1640 seq_escape(seq, subvol_name, " \t\n\\");
1646 static int btrfs_test_super(struct super_block *s, void *data)
1648 struct btrfs_fs_info *p = data;
1649 struct btrfs_fs_info *fs_info = btrfs_sb(s);
1651 return fs_info->fs_devices == p->fs_devices;
1654 static int btrfs_set_super(struct super_block *s, void *data)
1656 int err = set_anon_super(s, data);
1658 s->s_fs_info = data;
1663 * subvolumes are identified by ino 256
1665 static inline int is_subvolume_inode(struct inode *inode)
1667 if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
1672 static struct dentry *mount_subvol(const char *subvol_name, u64 subvol_objectid,
1673 struct vfsmount *mnt)
1675 struct dentry *root;
1679 if (!subvol_objectid) {
1680 ret = get_default_subvol_objectid(btrfs_sb(mnt->mnt_sb),
1683 root = ERR_PTR(ret);
1687 subvol_name = btrfs_get_subvol_name_from_objectid(
1688 btrfs_sb(mnt->mnt_sb), subvol_objectid);
1689 if (IS_ERR(subvol_name)) {
1690 root = ERR_CAST(subvol_name);
1697 root = mount_subtree(mnt, subvol_name);
1698 /* mount_subtree() drops our reference on the vfsmount. */
1701 if (!IS_ERR(root)) {
1702 struct super_block *s = root->d_sb;
1703 struct btrfs_fs_info *fs_info = btrfs_sb(s);
1704 struct inode *root_inode = d_inode(root);
1705 u64 root_objectid = BTRFS_I(root_inode)->root->root_key.objectid;
1708 if (!is_subvolume_inode(root_inode)) {
1709 btrfs_err(fs_info, "'%s' is not a valid subvolume",
1713 if (subvol_objectid && root_objectid != subvol_objectid) {
1715 * This will also catch a race condition where a
1716 * subvolume which was passed by ID is renamed and
1717 * another subvolume is renamed over the old location.
1720 "subvol '%s' does not match subvolid %llu",
1721 subvol_name, subvol_objectid);
1726 root = ERR_PTR(ret);
1727 deactivate_locked_super(s);
1738 * Find a superblock for the given device / mount point.
1740 * Note: This is based on mount_bdev from fs/super.c with a few additions
1741 * for multiple device setup. Make sure to keep it in sync.
1743 static struct dentry *btrfs_mount_root(struct file_system_type *fs_type,
1744 int flags, const char *device_name, void *data)
1746 struct block_device *bdev = NULL;
1747 struct super_block *s;
1748 struct btrfs_device *device = NULL;
1749 struct btrfs_fs_devices *fs_devices = NULL;
1750 struct btrfs_fs_info *fs_info = NULL;
1751 void *new_sec_opts = NULL;
1752 fmode_t mode = FMODE_READ;
1755 if (!(flags & SB_RDONLY))
1756 mode |= FMODE_WRITE;
1759 error = security_sb_eat_lsm_opts(data, &new_sec_opts);
1761 return ERR_PTR(error);
1765 * Setup a dummy root and fs_info for test/set super. This is because
1766 * we don't actually fill this stuff out until open_ctree, but we need
1767 * then open_ctree will properly initialize the file system specific
1768 * settings later. btrfs_init_fs_info initializes the static elements
1769 * of the fs_info (locks and such) to make cleanup easier if we find a
1770 * superblock with our given fs_devices later on at sget() time.
1772 fs_info = kvzalloc(sizeof(struct btrfs_fs_info), GFP_KERNEL);
1775 goto error_sec_opts;
1777 btrfs_init_fs_info(fs_info);
1779 fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
1780 fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
1781 if (!fs_info->super_copy || !fs_info->super_for_commit) {
1786 mutex_lock(&uuid_mutex);
1787 error = btrfs_parse_device_options(data, mode, fs_type);
1789 mutex_unlock(&uuid_mutex);
1793 device = btrfs_scan_one_device(device_name, mode, fs_type);
1794 if (IS_ERR(device)) {
1795 mutex_unlock(&uuid_mutex);
1796 error = PTR_ERR(device);
1800 fs_devices = device->fs_devices;
1801 fs_info->fs_devices = fs_devices;
1803 error = btrfs_open_devices(fs_devices, mode, fs_type);
1804 mutex_unlock(&uuid_mutex);
1808 if (!(flags & SB_RDONLY) && fs_devices->rw_devices == 0) {
1810 goto error_close_devices;
1813 bdev = fs_devices->latest_dev->bdev;
1814 s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | SB_NOSEC,
1818 goto error_close_devices;
1822 btrfs_close_devices(fs_devices);
1823 btrfs_free_fs_info(fs_info);
1824 if ((flags ^ s->s_flags) & SB_RDONLY)
1827 snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev);
1828 shrinker_debugfs_rename(&s->s_shrink, "sb-%s:%s", fs_type->name,
1830 btrfs_sb(s)->bdev_holder = fs_type;
1831 error = btrfs_fill_super(s, fs_devices, data);
1834 error = security_sb_set_mnt_opts(s, new_sec_opts, 0, NULL);
1835 security_free_mnt_opts(&new_sec_opts);
1837 deactivate_locked_super(s);
1838 return ERR_PTR(error);
1841 return dget(s->s_root);
1843 error_close_devices:
1844 btrfs_close_devices(fs_devices);
1846 btrfs_free_fs_info(fs_info);
1848 security_free_mnt_opts(&new_sec_opts);
1849 return ERR_PTR(error);
1853 * Mount function which is called by VFS layer.
1855 * In order to allow mounting a subvolume directly, btrfs uses mount_subtree()
1856 * which needs vfsmount* of device's root (/). This means device's root has to
1857 * be mounted internally in any case.
1860 * 1. Parse subvol id related options for later use in mount_subvol().
1862 * 2. Mount device's root (/) by calling vfs_kern_mount().
1864 * NOTE: vfs_kern_mount() is used by VFS to call btrfs_mount() in the
1865 * first place. In order to avoid calling btrfs_mount() again, we use
1866 * different file_system_type which is not registered to VFS by
1867 * register_filesystem() (btrfs_root_fs_type). As a result,
1868 * btrfs_mount_root() is called. The return value will be used by
1869 * mount_subtree() in mount_subvol().
1871 * 3. Call mount_subvol() to get the dentry of subvolume. Since there is
1872 * "btrfs subvolume set-default", mount_subvol() is called always.
1874 static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
1875 const char *device_name, void *data)
1877 struct vfsmount *mnt_root;
1878 struct dentry *root;
1879 char *subvol_name = NULL;
1880 u64 subvol_objectid = 0;
1883 error = btrfs_parse_subvol_options(data, &subvol_name,
1887 return ERR_PTR(error);
1890 /* mount device's root (/) */
1891 mnt_root = vfs_kern_mount(&btrfs_root_fs_type, flags, device_name, data);
1892 if (PTR_ERR_OR_ZERO(mnt_root) == -EBUSY) {
1893 if (flags & SB_RDONLY) {
1894 mnt_root = vfs_kern_mount(&btrfs_root_fs_type,
1895 flags & ~SB_RDONLY, device_name, data);
1897 mnt_root = vfs_kern_mount(&btrfs_root_fs_type,
1898 flags | SB_RDONLY, device_name, data);
1899 if (IS_ERR(mnt_root)) {
1900 root = ERR_CAST(mnt_root);
1905 down_write(&mnt_root->mnt_sb->s_umount);
1906 error = btrfs_remount(mnt_root->mnt_sb, &flags, NULL);
1907 up_write(&mnt_root->mnt_sb->s_umount);
1909 root = ERR_PTR(error);
1916 if (IS_ERR(mnt_root)) {
1917 root = ERR_CAST(mnt_root);
1922 /* mount_subvol() will free subvol_name and mnt_root */
1923 root = mount_subvol(subvol_name, subvol_objectid, mnt_root);
1929 static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
1930 u32 new_pool_size, u32 old_pool_size)
1932 if (new_pool_size == old_pool_size)
1935 fs_info->thread_pool_size = new_pool_size;
1937 btrfs_info(fs_info, "resize thread pool %d -> %d",
1938 old_pool_size, new_pool_size);
1940 btrfs_workqueue_set_max(fs_info->workers, new_pool_size);
1941 btrfs_workqueue_set_max(fs_info->hipri_workers, new_pool_size);
1942 btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size);
1943 btrfs_workqueue_set_max(fs_info->caching_workers, new_pool_size);
1944 workqueue_set_max_active(fs_info->endio_workers, new_pool_size);
1945 workqueue_set_max_active(fs_info->endio_meta_workers, new_pool_size);
1946 btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size);
1947 btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
1948 btrfs_workqueue_set_max(fs_info->delayed_workers, new_pool_size);
1951 static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info,
1952 unsigned long old_opts, int flags)
1954 if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1955 (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1956 (flags & SB_RDONLY))) {
1957 /* wait for any defraggers to finish */
1958 wait_event(fs_info->transaction_wait,
1959 (atomic_read(&fs_info->defrag_running) == 0));
1960 if (flags & SB_RDONLY)
1961 sync_filesystem(fs_info->sb);
1965 static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
1966 unsigned long old_opts)
1968 const bool cache_opt = btrfs_test_opt(fs_info, SPACE_CACHE);
1971 * We need to cleanup all defragable inodes if the autodefragment is
1972 * close or the filesystem is read only.
1974 if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1975 (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) || sb_rdonly(fs_info->sb))) {
1976 btrfs_cleanup_defrag_inodes(fs_info);
1979 /* If we toggled discard async */
1980 if (!btrfs_raw_test_opt(old_opts, DISCARD_ASYNC) &&
1981 btrfs_test_opt(fs_info, DISCARD_ASYNC))
1982 btrfs_discard_resume(fs_info);
1983 else if (btrfs_raw_test_opt(old_opts, DISCARD_ASYNC) &&
1984 !btrfs_test_opt(fs_info, DISCARD_ASYNC))
1985 btrfs_discard_cleanup(fs_info);
1987 /* If we toggled space cache */
1988 if (cache_opt != btrfs_free_space_cache_v1_active(fs_info))
1989 btrfs_set_free_space_cache_v1_active(fs_info, cache_opt);
1992 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
1994 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1995 unsigned old_flags = sb->s_flags;
1996 unsigned long old_opts = fs_info->mount_opt;
1997 unsigned long old_compress_type = fs_info->compress_type;
1998 u64 old_max_inline = fs_info->max_inline;
1999 u32 old_thread_pool_size = fs_info->thread_pool_size;
2000 u32 old_metadata_ratio = fs_info->metadata_ratio;
2003 sync_filesystem(sb);
2004 set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
2007 void *new_sec_opts = NULL;
2009 ret = security_sb_eat_lsm_opts(data, &new_sec_opts);
2011 ret = security_sb_remount(sb, new_sec_opts);
2012 security_free_mnt_opts(&new_sec_opts);
2017 ret = btrfs_parse_options(fs_info, data, *flags);
2021 ret = btrfs_check_features(fs_info, !(*flags & SB_RDONLY));
2025 btrfs_remount_begin(fs_info, old_opts, *flags);
2026 btrfs_resize_thread_pool(fs_info,
2027 fs_info->thread_pool_size, old_thread_pool_size);
2029 if ((bool)btrfs_test_opt(fs_info, FREE_SPACE_TREE) !=
2030 (bool)btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE) &&
2031 (!sb_rdonly(sb) || (*flags & SB_RDONLY))) {
2033 "remount supports changing free space tree only from ro to rw");
2034 /* Make sure free space cache options match the state on disk */
2035 if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE)) {
2036 btrfs_set_opt(fs_info->mount_opt, FREE_SPACE_TREE);
2037 btrfs_clear_opt(fs_info->mount_opt, SPACE_CACHE);
2039 if (btrfs_free_space_cache_v1_active(fs_info)) {
2040 btrfs_clear_opt(fs_info->mount_opt, FREE_SPACE_TREE);
2041 btrfs_set_opt(fs_info->mount_opt, SPACE_CACHE);
2045 if ((bool)(*flags & SB_RDONLY) == sb_rdonly(sb))
2048 if (*flags & SB_RDONLY) {
2050 * this also happens on 'umount -rf' or on shutdown, when
2051 * the filesystem is busy.
2053 cancel_work_sync(&fs_info->async_reclaim_work);
2054 cancel_work_sync(&fs_info->async_data_reclaim_work);
2056 btrfs_discard_cleanup(fs_info);
2058 /* wait for the uuid_scan task to finish */
2059 down(&fs_info->uuid_tree_rescan_sem);
2060 /* avoid complains from lockdep et al. */
2061 up(&fs_info->uuid_tree_rescan_sem);
2063 btrfs_set_sb_rdonly(sb);
2066 * Setting SB_RDONLY will put the cleaner thread to
2067 * sleep at the next loop if it's already active.
2068 * If it's already asleep, we'll leave unused block
2069 * groups on disk until we're mounted read-write again
2070 * unless we clean them up here.
2072 btrfs_delete_unused_bgs(fs_info);
2075 * The cleaner task could be already running before we set the
2076 * flag BTRFS_FS_STATE_RO (and SB_RDONLY in the superblock).
2077 * We must make sure that after we finish the remount, i.e. after
2078 * we call btrfs_commit_super(), the cleaner can no longer start
2079 * a transaction - either because it was dropping a dead root,
2080 * running delayed iputs or deleting an unused block group (the
2081 * cleaner picked a block group from the list of unused block
2082 * groups before we were able to in the previous call to
2083 * btrfs_delete_unused_bgs()).
2085 wait_on_bit(&fs_info->flags, BTRFS_FS_CLEANER_RUNNING,
2086 TASK_UNINTERRUPTIBLE);
2089 * We've set the superblock to RO mode, so we might have made
2090 * the cleaner task sleep without running all pending delayed
2091 * iputs. Go through all the delayed iputs here, so that if an
2092 * unmount happens without remounting RW we don't end up at
2093 * finishing close_ctree() with a non-empty list of delayed
2096 btrfs_run_delayed_iputs(fs_info);
2098 btrfs_dev_replace_suspend_for_unmount(fs_info);
2099 btrfs_scrub_cancel(fs_info);
2100 btrfs_pause_balance(fs_info);
2103 * Pause the qgroup rescan worker if it is running. We don't want
2104 * it to be still running after we are in RO mode, as after that,
2105 * by the time we unmount, it might have left a transaction open,
2106 * so we would leak the transaction and/or crash.
2108 btrfs_qgroup_wait_for_completion(fs_info, false);
2110 ret = btrfs_commit_super(fs_info);
2114 if (BTRFS_FS_ERROR(fs_info)) {
2116 "Remounting read-write after error is not allowed");
2120 if (fs_info->fs_devices->rw_devices == 0) {
2125 if (!btrfs_check_rw_degradable(fs_info, NULL)) {
2127 "too many missing devices, writable remount is not allowed");
2132 if (btrfs_super_log_root(fs_info->super_copy) != 0) {
2134 "mount required to replay tree-log, cannot remount read-write");
2140 * NOTE: when remounting with a change that does writes, don't
2141 * put it anywhere above this point, as we are not sure to be
2142 * safe to write until we pass the above checks.
2144 ret = btrfs_start_pre_rw_mount(fs_info);
2148 btrfs_clear_sb_rdonly(sb);
2150 set_bit(BTRFS_FS_OPEN, &fs_info->flags);
2154 * We need to set SB_I_VERSION here otherwise it'll get cleared by VFS,
2155 * since the absence of the flag means it can be toggled off by remount.
2157 *flags |= SB_I_VERSION;
2159 wake_up_process(fs_info->transaction_kthread);
2160 btrfs_remount_cleanup(fs_info, old_opts);
2161 btrfs_clear_oneshot_options(fs_info);
2162 clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
2167 /* We've hit an error - don't reset SB_RDONLY */
2169 old_flags |= SB_RDONLY;
2170 if (!(old_flags & SB_RDONLY))
2171 clear_bit(BTRFS_FS_STATE_RO, &fs_info->fs_state);
2172 sb->s_flags = old_flags;
2173 fs_info->mount_opt = old_opts;
2174 fs_info->compress_type = old_compress_type;
2175 fs_info->max_inline = old_max_inline;
2176 btrfs_resize_thread_pool(fs_info,
2177 old_thread_pool_size, fs_info->thread_pool_size);
2178 fs_info->metadata_ratio = old_metadata_ratio;
2179 btrfs_remount_cleanup(fs_info, old_opts);
2180 clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
2185 /* Used to sort the devices by max_avail(descending sort) */
2186 static int btrfs_cmp_device_free_bytes(const void *a, const void *b)
2188 const struct btrfs_device_info *dev_info1 = a;
2189 const struct btrfs_device_info *dev_info2 = b;
2191 if (dev_info1->max_avail > dev_info2->max_avail)
2193 else if (dev_info1->max_avail < dev_info2->max_avail)
2199 * sort the devices by max_avail, in which max free extent size of each device
2200 * is stored.(Descending Sort)
2202 static inline void btrfs_descending_sort_devices(
2203 struct btrfs_device_info *devices,
2206 sort(devices, nr_devices, sizeof(struct btrfs_device_info),
2207 btrfs_cmp_device_free_bytes, NULL);
2211 * The helper to calc the free space on the devices that can be used to store
2214 static inline int btrfs_calc_avail_data_space(struct btrfs_fs_info *fs_info,
2217 struct btrfs_device_info *devices_info;
2218 struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
2219 struct btrfs_device *device;
2222 u64 min_stripe_size;
2223 int num_stripes = 1;
2224 int i = 0, nr_devices;
2225 const struct btrfs_raid_attr *rattr;
2228 * We aren't under the device list lock, so this is racy-ish, but good
2229 * enough for our purposes.
2231 nr_devices = fs_info->fs_devices->open_devices;
2234 nr_devices = fs_info->fs_devices->open_devices;
2242 devices_info = kmalloc_array(nr_devices, sizeof(*devices_info),
2247 /* calc min stripe number for data space allocation */
2248 type = btrfs_data_alloc_profile(fs_info);
2249 rattr = &btrfs_raid_array[btrfs_bg_flags_to_raid_index(type)];
2251 if (type & BTRFS_BLOCK_GROUP_RAID0)
2252 num_stripes = nr_devices;
2253 else if (type & BTRFS_BLOCK_GROUP_RAID1_MASK)
2254 num_stripes = rattr->ncopies;
2255 else if (type & BTRFS_BLOCK_GROUP_RAID10)
2258 /* Adjust for more than 1 stripe per device */
2259 min_stripe_size = rattr->dev_stripes * BTRFS_STRIPE_LEN;
2262 list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
2263 if (!test_bit(BTRFS_DEV_STATE_IN_FS_METADATA,
2264 &device->dev_state) ||
2266 test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state))
2269 if (i >= nr_devices)
2272 avail_space = device->total_bytes - device->bytes_used;
2274 /* align with stripe_len */
2275 avail_space = rounddown(avail_space, BTRFS_STRIPE_LEN);
2278 * Ensure we have at least min_stripe_size on top of the
2279 * reserved space on the device.
2281 if (avail_space <= BTRFS_DEVICE_RANGE_RESERVED + min_stripe_size)
2284 avail_space -= BTRFS_DEVICE_RANGE_RESERVED;
2286 devices_info[i].dev = device;
2287 devices_info[i].max_avail = avail_space;
2295 btrfs_descending_sort_devices(devices_info, nr_devices);
2299 while (nr_devices >= rattr->devs_min) {
2300 num_stripes = min(num_stripes, nr_devices);
2302 if (devices_info[i].max_avail >= min_stripe_size) {
2306 avail_space += devices_info[i].max_avail * num_stripes;
2307 alloc_size = devices_info[i].max_avail;
2308 for (j = i + 1 - num_stripes; j <= i; j++)
2309 devices_info[j].max_avail -= alloc_size;
2315 kfree(devices_info);
2316 *free_bytes = avail_space;
2321 * Calculate numbers for 'df', pessimistic in case of mixed raid profiles.
2323 * If there's a redundant raid level at DATA block groups, use the respective
2324 * multiplier to scale the sizes.
2326 * Unused device space usage is based on simulating the chunk allocator
2327 * algorithm that respects the device sizes and order of allocations. This is
2328 * a close approximation of the actual use but there are other factors that may
2329 * change the result (like a new metadata chunk).
2331 * If metadata is exhausted, f_bavail will be 0.
2333 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
2335 struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
2336 struct btrfs_super_block *disk_super = fs_info->super_copy;
2337 struct btrfs_space_info *found;
2339 u64 total_free_data = 0;
2340 u64 total_free_meta = 0;
2341 u32 bits = fs_info->sectorsize_bits;
2342 __be32 *fsid = (__be32 *)fs_info->fs_devices->fsid;
2343 unsigned factor = 1;
2344 struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
2349 list_for_each_entry(found, &fs_info->space_info, list) {
2350 if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
2353 total_free_data += found->disk_total - found->disk_used;
2355 btrfs_account_ro_block_groups_free_space(found);
2357 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
2358 if (!list_empty(&found->block_groups[i]))
2359 factor = btrfs_bg_type_to_factor(
2360 btrfs_raid_array[i].bg_flag);
2365 * Metadata in mixed block goup profiles are accounted in data
2367 if (!mixed && found->flags & BTRFS_BLOCK_GROUP_METADATA) {
2368 if (found->flags & BTRFS_BLOCK_GROUP_DATA)
2371 total_free_meta += found->disk_total -
2375 total_used += found->disk_used;
2378 buf->f_blocks = div_u64(btrfs_super_total_bytes(disk_super), factor);
2379 buf->f_blocks >>= bits;
2380 buf->f_bfree = buf->f_blocks - (div_u64(total_used, factor) >> bits);
2382 /* Account global block reserve as used, it's in logical size already */
2383 spin_lock(&block_rsv->lock);
2384 /* Mixed block groups accounting is not byte-accurate, avoid overflow */
2385 if (buf->f_bfree >= block_rsv->size >> bits)
2386 buf->f_bfree -= block_rsv->size >> bits;
2389 spin_unlock(&block_rsv->lock);
2391 buf->f_bavail = div_u64(total_free_data, factor);
2392 ret = btrfs_calc_avail_data_space(fs_info, &total_free_data);
2395 buf->f_bavail += div_u64(total_free_data, factor);
2396 buf->f_bavail = buf->f_bavail >> bits;
2399 * We calculate the remaining metadata space minus global reserve. If
2400 * this is (supposedly) smaller than zero, there's no space. But this
2401 * does not hold in practice, the exhausted state happens where's still
2402 * some positive delta. So we apply some guesswork and compare the
2403 * delta to a 4M threshold. (Practically observed delta was ~2M.)
2405 * We probably cannot calculate the exact threshold value because this
2406 * depends on the internal reservations requested by various
2407 * operations, so some operations that consume a few metadata will
2408 * succeed even if the Avail is zero. But this is better than the other
2414 * We only want to claim there's no available space if we can no longer
2415 * allocate chunks for our metadata profile and our global reserve will
2416 * not fit in the free metadata space. If we aren't ->full then we
2417 * still can allocate chunks and thus are fine using the currently
2418 * calculated f_bavail.
2420 if (!mixed && block_rsv->space_info->full &&
2421 total_free_meta - thresh < block_rsv->size)
2424 buf->f_type = BTRFS_SUPER_MAGIC;
2425 buf->f_bsize = dentry->d_sb->s_blocksize;
2426 buf->f_namelen = BTRFS_NAME_LEN;
2428 /* We treat it as constant endianness (it doesn't matter _which_)
2429 because we want the fsid to come out the same whether mounted
2430 on a big-endian or little-endian host */
2431 buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
2432 buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
2433 /* Mask in the root object ID too, to disambiguate subvols */
2434 buf->f_fsid.val[0] ^=
2435 BTRFS_I(d_inode(dentry))->root->root_key.objectid >> 32;
2436 buf->f_fsid.val[1] ^=
2437 BTRFS_I(d_inode(dentry))->root->root_key.objectid;
2442 static void btrfs_kill_super(struct super_block *sb)
2444 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2445 kill_anon_super(sb);
2446 btrfs_free_fs_info(fs_info);
2449 static struct file_system_type btrfs_fs_type = {
2450 .owner = THIS_MODULE,
2452 .mount = btrfs_mount,
2453 .kill_sb = btrfs_kill_super,
2454 .fs_flags = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,
2457 static struct file_system_type btrfs_root_fs_type = {
2458 .owner = THIS_MODULE,
2460 .mount = btrfs_mount_root,
2461 .kill_sb = btrfs_kill_super,
2462 .fs_flags = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA | FS_ALLOW_IDMAP,
2465 MODULE_ALIAS_FS("btrfs");
2467 static int btrfs_control_open(struct inode *inode, struct file *file)
2470 * The control file's private_data is used to hold the
2471 * transaction when it is started and is used to keep
2472 * track of whether a transaction is already in progress.
2474 file->private_data = NULL;
2479 * Used by /dev/btrfs-control for devices ioctls.
2481 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
2484 struct btrfs_ioctl_vol_args *vol;
2485 struct btrfs_device *device = NULL;
2489 if (!capable(CAP_SYS_ADMIN))
2492 vol = memdup_user((void __user *)arg, sizeof(*vol));
2494 return PTR_ERR(vol);
2495 vol->name[BTRFS_PATH_NAME_MAX] = '\0';
2498 case BTRFS_IOC_SCAN_DEV:
2499 mutex_lock(&uuid_mutex);
2500 device = btrfs_scan_one_device(vol->name, FMODE_READ,
2501 &btrfs_root_fs_type);
2502 ret = PTR_ERR_OR_ZERO(device);
2503 mutex_unlock(&uuid_mutex);
2505 case BTRFS_IOC_FORGET_DEV:
2506 if (vol->name[0] != 0) {
2507 ret = lookup_bdev(vol->name, &devt);
2511 ret = btrfs_forget_devices(devt);
2513 case BTRFS_IOC_DEVICES_READY:
2514 mutex_lock(&uuid_mutex);
2515 device = btrfs_scan_one_device(vol->name, FMODE_READ,
2516 &btrfs_root_fs_type);
2517 if (IS_ERR(device)) {
2518 mutex_unlock(&uuid_mutex);
2519 ret = PTR_ERR(device);
2522 ret = !(device->fs_devices->num_devices ==
2523 device->fs_devices->total_devices);
2524 mutex_unlock(&uuid_mutex);
2526 case BTRFS_IOC_GET_SUPPORTED_FEATURES:
2527 ret = btrfs_ioctl_get_supported_features((void __user*)arg);
2535 static int btrfs_freeze(struct super_block *sb)
2537 struct btrfs_trans_handle *trans;
2538 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2539 struct btrfs_root *root = fs_info->tree_root;
2541 set_bit(BTRFS_FS_FROZEN, &fs_info->flags);
2543 * We don't need a barrier here, we'll wait for any transaction that
2544 * could be in progress on other threads (and do delayed iputs that
2545 * we want to avoid on a frozen filesystem), or do the commit
2548 trans = btrfs_attach_transaction_barrier(root);
2549 if (IS_ERR(trans)) {
2550 /* no transaction, don't bother */
2551 if (PTR_ERR(trans) == -ENOENT)
2553 return PTR_ERR(trans);
2555 return btrfs_commit_transaction(trans);
2558 static int check_dev_super(struct btrfs_device *dev)
2560 struct btrfs_fs_info *fs_info = dev->fs_info;
2561 struct btrfs_super_block *sb;
2565 /* This should be called with fs still frozen. */
2566 ASSERT(test_bit(BTRFS_FS_FROZEN, &fs_info->flags));
2568 /* Missing dev, no need to check. */
2572 /* Only need to check the primary super block. */
2573 sb = btrfs_read_dev_one_super(dev->bdev, 0, true);
2577 /* Verify the checksum. */
2578 csum_type = btrfs_super_csum_type(sb);
2579 if (csum_type != btrfs_super_csum_type(fs_info->super_copy)) {
2580 btrfs_err(fs_info, "csum type changed, has %u expect %u",
2581 csum_type, btrfs_super_csum_type(fs_info->super_copy));
2586 if (btrfs_check_super_csum(fs_info, sb)) {
2587 btrfs_err(fs_info, "csum for on-disk super block no longer matches");
2592 /* Btrfs_validate_super() includes fsid check against super->fsid. */
2593 ret = btrfs_validate_super(fs_info, sb, 0);
2597 if (btrfs_super_generation(sb) != fs_info->last_trans_committed) {
2598 btrfs_err(fs_info, "transid mismatch, has %llu expect %llu",
2599 btrfs_super_generation(sb),
2600 fs_info->last_trans_committed);
2605 btrfs_release_disk_super(sb);
2609 static int btrfs_unfreeze(struct super_block *sb)
2611 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2612 struct btrfs_device *device;
2616 * Make sure the fs is not changed by accident (like hibernation then
2617 * modified by other OS).
2618 * If we found anything wrong, we mark the fs error immediately.
2620 * And since the fs is frozen, no one can modify the fs yet, thus
2621 * we don't need to hold device_list_mutex.
2623 list_for_each_entry(device, &fs_info->fs_devices->devices, dev_list) {
2624 ret = check_dev_super(device);
2626 btrfs_handle_fs_error(fs_info, ret,
2627 "super block on devid %llu got modified unexpectedly",
2632 clear_bit(BTRFS_FS_FROZEN, &fs_info->flags);
2635 * We still return 0, to allow VFS layer to unfreeze the fs even the
2636 * above checks failed. Since the fs is either fine or read-only, we're
2637 * safe to continue, without causing further damage.
2642 static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
2644 struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
2647 * There should be always a valid pointer in latest_dev, it may be stale
2648 * for a short moment in case it's being deleted but still valid until
2649 * the end of RCU grace period.
2652 seq_escape(m, rcu_str_deref(fs_info->fs_devices->latest_dev->name), " \t\n\\");
2658 static const struct super_operations btrfs_super_ops = {
2659 .drop_inode = btrfs_drop_inode,
2660 .evict_inode = btrfs_evict_inode,
2661 .put_super = btrfs_put_super,
2662 .sync_fs = btrfs_sync_fs,
2663 .show_options = btrfs_show_options,
2664 .show_devname = btrfs_show_devname,
2665 .alloc_inode = btrfs_alloc_inode,
2666 .destroy_inode = btrfs_destroy_inode,
2667 .free_inode = btrfs_free_inode,
2668 .statfs = btrfs_statfs,
2669 .remount_fs = btrfs_remount,
2670 .freeze_fs = btrfs_freeze,
2671 .unfreeze_fs = btrfs_unfreeze,
2674 static const struct file_operations btrfs_ctl_fops = {
2675 .open = btrfs_control_open,
2676 .unlocked_ioctl = btrfs_control_ioctl,
2677 .compat_ioctl = compat_ptr_ioctl,
2678 .owner = THIS_MODULE,
2679 .llseek = noop_llseek,
2682 static struct miscdevice btrfs_misc = {
2683 .minor = BTRFS_MINOR,
2684 .name = "btrfs-control",
2685 .fops = &btrfs_ctl_fops
2688 MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
2689 MODULE_ALIAS("devname:btrfs-control");
2691 static int __init btrfs_interface_init(void)
2693 return misc_register(&btrfs_misc);
2696 static __cold void btrfs_interface_exit(void)
2698 misc_deregister(&btrfs_misc);
2701 static void __init btrfs_print_mod_info(void)
2703 static const char options[] = ""
2704 #ifdef CONFIG_BTRFS_DEBUG
2707 #ifdef CONFIG_BTRFS_ASSERT
2710 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
2711 ", integrity-checker=on"
2713 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
2716 #ifdef CONFIG_BLK_DEV_ZONED
2721 #ifdef CONFIG_FS_VERITY
2727 pr_info("Btrfs loaded, crc32c=%s%s\n", crc32c_impl(), options);
2730 static int __init init_btrfs_fs(void)
2736 err = btrfs_init_sysfs();
2740 btrfs_init_compress();
2742 err = btrfs_init_cachep();
2746 err = extent_state_init_cachep();
2750 err = extent_buffer_init_cachep();
2752 goto free_extent_cachep;
2754 err = btrfs_bioset_init();
2756 goto free_eb_cachep;
2758 err = extent_map_init();
2762 err = ordered_data_init();
2764 goto free_extent_map;
2766 err = btrfs_delayed_inode_init();
2768 goto free_ordered_data;
2770 err = btrfs_auto_defrag_init();
2772 goto free_delayed_inode;
2774 err = btrfs_delayed_ref_init();
2776 goto free_auto_defrag;
2778 err = btrfs_prelim_ref_init();
2780 goto free_delayed_ref;
2782 err = btrfs_interface_init();
2784 goto free_prelim_ref;
2786 btrfs_print_mod_info();
2788 err = btrfs_run_sanity_tests();
2790 goto unregister_ioctl;
2792 err = register_filesystem(&btrfs_fs_type);
2794 goto unregister_ioctl;
2799 btrfs_interface_exit();
2801 btrfs_prelim_ref_exit();
2803 btrfs_delayed_ref_exit();
2805 btrfs_auto_defrag_exit();
2807 btrfs_delayed_inode_exit();
2809 ordered_data_exit();
2813 btrfs_bioset_exit();
2815 extent_buffer_free_cachep();
2817 extent_state_free_cachep();
2819 btrfs_destroy_cachep();
2821 btrfs_exit_compress();
2827 static void __exit exit_btrfs_fs(void)
2829 btrfs_destroy_cachep();
2830 btrfs_delayed_ref_exit();
2831 btrfs_auto_defrag_exit();
2832 btrfs_delayed_inode_exit();
2833 btrfs_prelim_ref_exit();
2834 ordered_data_exit();
2836 btrfs_bioset_exit();
2837 extent_state_free_cachep();
2838 extent_buffer_free_cachep();
2839 btrfs_interface_exit();
2840 unregister_filesystem(&btrfs_fs_type);
2842 btrfs_cleanup_fs_uuids();
2843 btrfs_exit_compress();
2846 late_initcall(init_btrfs_fs);
2847 module_exit(exit_btrfs_fs)
2849 MODULE_LICENSE("GPL");
2850 MODULE_SOFTDEP("pre: crc32c");
2851 MODULE_SOFTDEP("pre: xxhash64");
2852 MODULE_SOFTDEP("pre: sha256");
2853 MODULE_SOFTDEP("pre: blake2b-256");