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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2007 Oracle. All rights reserved.
4 */
5
6#include <linux/blkdev.h>
7#include <linux/module.h>
8#include <linux/fs.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 <linux/security.h>
30#include <linux/fs_parser.h>
31#include "messages.h"
32#include "delayed-inode.h"
33#include "ctree.h"
34#include "disk-io.h"
35#include "transaction.h"
36#include "btrfs_inode.h"
37#include "print-tree.h"
38#include "props.h"
39#include "xattr.h"
40#include "bio.h"
41#include "export.h"
42#include "compression.h"
43#include "rcu-string.h"
44#include "dev-replace.h"
45#include "free-space-cache.h"
46#include "backref.h"
47#include "space-info.h"
48#include "sysfs.h"
49#include "zoned.h"
50#include "tests/btrfs-tests.h"
51#include "block-group.h"
52#include "discard.h"
53#include "qgroup.h"
54#include "raid56.h"
55#include "fs.h"
56#include "accessors.h"
57#include "defrag.h"
58#include "dir-item.h"
59#include "ioctl.h"
60#include "scrub.h"
61#include "verity.h"
62#include "super.h"
63#include "extent-tree.h"
64#define CREATE_TRACE_POINTS
65#include <trace/events/btrfs.h>
66
67static const struct super_operations btrfs_super_ops;
68static struct file_system_type btrfs_fs_type;
69
70static void btrfs_put_super(struct super_block *sb)
71{
72 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
73
74 btrfs_info(fs_info, "last unmount of filesystem %pU", fs_info->fs_devices->fsid);
75 close_ctree(fs_info);
76}
77
78/* Store the mount options related information. */
79struct btrfs_fs_context {
80 char *subvol_name;
81 u64 subvol_objectid;
82 u64 max_inline;
83 u32 commit_interval;
84 u32 metadata_ratio;
85 u32 thread_pool_size;
86 unsigned long mount_opt;
87 unsigned long compress_type:4;
88 unsigned int compress_level;
89 refcount_t refs;
90};
91
92enum {
93 Opt_acl,
94 Opt_clear_cache,
95 Opt_commit_interval,
96 Opt_compress,
97 Opt_compress_force,
98 Opt_compress_force_type,
99 Opt_compress_type,
100 Opt_degraded,
101 Opt_device,
102 Opt_fatal_errors,
103 Opt_flushoncommit,
104 Opt_max_inline,
105 Opt_barrier,
106 Opt_datacow,
107 Opt_datasum,
108 Opt_defrag,
109 Opt_discard,
110 Opt_discard_mode,
111 Opt_ratio,
112 Opt_rescan_uuid_tree,
113 Opt_skip_balance,
114 Opt_space_cache,
115 Opt_space_cache_version,
116 Opt_ssd,
117 Opt_ssd_spread,
118 Opt_subvol,
119 Opt_subvol_empty,
120 Opt_subvolid,
121 Opt_thread_pool,
122 Opt_treelog,
123 Opt_user_subvol_rm_allowed,
124
125 /* Rescue options */
126 Opt_rescue,
127 Opt_usebackuproot,
128 Opt_nologreplay,
129 Opt_ignorebadroots,
130 Opt_ignoredatacsums,
131 Opt_rescue_all,
132
133 /* Debugging options */
134 Opt_enospc_debug,
135#ifdef CONFIG_BTRFS_DEBUG
136 Opt_fragment, Opt_fragment_data, Opt_fragment_metadata, Opt_fragment_all,
137#endif
138#ifdef CONFIG_BTRFS_FS_REF_VERIFY
139 Opt_ref_verify,
140#endif
141 Opt_err,
142};
143
144enum {
145 Opt_fatal_errors_panic,
146 Opt_fatal_errors_bug,
147};
148
149static const struct constant_table btrfs_parameter_fatal_errors[] = {
150 { "panic", Opt_fatal_errors_panic },
151 { "bug", Opt_fatal_errors_bug },
152 {}
153};
154
155enum {
156 Opt_discard_sync,
157 Opt_discard_async,
158};
159
160static const struct constant_table btrfs_parameter_discard[] = {
161 { "sync", Opt_discard_sync },
162 { "async", Opt_discard_async },
163 {}
164};
165
166enum {
167 Opt_space_cache_v1,
168 Opt_space_cache_v2,
169};
170
171static const struct constant_table btrfs_parameter_space_cache[] = {
172 { "v1", Opt_space_cache_v1 },
173 { "v2", Opt_space_cache_v2 },
174 {}
175};
176
177enum {
178 Opt_rescue_usebackuproot,
179 Opt_rescue_nologreplay,
180 Opt_rescue_ignorebadroots,
181 Opt_rescue_ignoredatacsums,
182 Opt_rescue_parameter_all,
183};
184
185static const struct constant_table btrfs_parameter_rescue[] = {
186 { "usebackuproot", Opt_rescue_usebackuproot },
187 { "nologreplay", Opt_rescue_nologreplay },
188 { "ignorebadroots", Opt_rescue_ignorebadroots },
189 { "ibadroots", Opt_rescue_ignorebadroots },
190 { "ignoredatacsums", Opt_rescue_ignoredatacsums },
191 { "idatacsums", Opt_rescue_ignoredatacsums },
192 { "all", Opt_rescue_parameter_all },
193 {}
194};
195
196#ifdef CONFIG_BTRFS_DEBUG
197enum {
198 Opt_fragment_parameter_data,
199 Opt_fragment_parameter_metadata,
200 Opt_fragment_parameter_all,
201};
202
203static const struct constant_table btrfs_parameter_fragment[] = {
204 { "data", Opt_fragment_parameter_data },
205 { "metadata", Opt_fragment_parameter_metadata },
206 { "all", Opt_fragment_parameter_all },
207 {}
208};
209#endif
210
211static const struct fs_parameter_spec btrfs_fs_parameters[] = {
212 fsparam_flag_no("acl", Opt_acl),
213 fsparam_flag_no("autodefrag", Opt_defrag),
214 fsparam_flag_no("barrier", Opt_barrier),
215 fsparam_flag("clear_cache", Opt_clear_cache),
216 fsparam_u32("commit", Opt_commit_interval),
217 fsparam_flag("compress", Opt_compress),
218 fsparam_string("compress", Opt_compress_type),
219 fsparam_flag("compress-force", Opt_compress_force),
220 fsparam_string("compress-force", Opt_compress_force_type),
221 fsparam_flag_no("datacow", Opt_datacow),
222 fsparam_flag_no("datasum", Opt_datasum),
223 fsparam_flag("degraded", Opt_degraded),
224 fsparam_string("device", Opt_device),
225 fsparam_flag_no("discard", Opt_discard),
226 fsparam_enum("discard", Opt_discard_mode, btrfs_parameter_discard),
227 fsparam_enum("fatal_errors", Opt_fatal_errors, btrfs_parameter_fatal_errors),
228 fsparam_flag_no("flushoncommit", Opt_flushoncommit),
229 fsparam_string("max_inline", Opt_max_inline),
230 fsparam_u32("metadata_ratio", Opt_ratio),
231 fsparam_flag("rescan_uuid_tree", Opt_rescan_uuid_tree),
232 fsparam_flag("skip_balance", Opt_skip_balance),
233 fsparam_flag_no("space_cache", Opt_space_cache),
234 fsparam_enum("space_cache", Opt_space_cache_version, btrfs_parameter_space_cache),
235 fsparam_flag_no("ssd", Opt_ssd),
236 fsparam_flag_no("ssd_spread", Opt_ssd_spread),
237 fsparam_string("subvol", Opt_subvol),
238 fsparam_flag("subvol=", Opt_subvol_empty),
239 fsparam_u64("subvolid", Opt_subvolid),
240 fsparam_u32("thread_pool", Opt_thread_pool),
241 fsparam_flag_no("treelog", Opt_treelog),
242 fsparam_flag("user_subvol_rm_allowed", Opt_user_subvol_rm_allowed),
243
244 /* Rescue options. */
245 fsparam_enum("rescue", Opt_rescue, btrfs_parameter_rescue),
246 /* Deprecated, with alias rescue=nologreplay */
247 __fsparam(NULL, "nologreplay", Opt_nologreplay, fs_param_deprecated, NULL),
248 /* Deprecated, with alias rescue=usebackuproot */
249 __fsparam(NULL, "usebackuproot", Opt_usebackuproot, fs_param_deprecated, NULL),
250
251 /* Debugging options. */
252 fsparam_flag_no("enospc_debug", Opt_enospc_debug),
253#ifdef CONFIG_BTRFS_DEBUG
254 fsparam_enum("fragment", Opt_fragment, btrfs_parameter_fragment),
255#endif
256#ifdef CONFIG_BTRFS_FS_REF_VERIFY
257 fsparam_flag("ref_verify", Opt_ref_verify),
258#endif
259 {}
260};
261
262/* No support for restricting writes to btrfs devices yet... */
263static inline blk_mode_t btrfs_open_mode(struct fs_context *fc)
264{
265 return sb_open_mode(fc->sb_flags) & ~BLK_OPEN_RESTRICT_WRITES;
266}
267
268static int btrfs_parse_param(struct fs_context *fc, struct fs_parameter *param)
269{
270 struct btrfs_fs_context *ctx = fc->fs_private;
271 struct fs_parse_result result;
272 int opt;
273
274 opt = fs_parse(fc, btrfs_fs_parameters, param, &result);
275 if (opt < 0)
276 return opt;
277
278 switch (opt) {
279 case Opt_degraded:
280 btrfs_set_opt(ctx->mount_opt, DEGRADED);
281 break;
282 case Opt_subvol_empty:
283 /*
284 * This exists because we used to allow it on accident, so we're
285 * keeping it to maintain ABI. See 37becec95ac3 ("Btrfs: allow
286 * empty subvol= again").
287 */
288 break;
289 case Opt_subvol:
290 kfree(ctx->subvol_name);
291 ctx->subvol_name = kstrdup(param->string, GFP_KERNEL);
292 if (!ctx->subvol_name)
293 return -ENOMEM;
294 break;
295 case Opt_subvolid:
296 ctx->subvol_objectid = result.uint_64;
297
298 /* subvolid=0 means give me the original fs_tree. */
299 if (!ctx->subvol_objectid)
300 ctx->subvol_objectid = BTRFS_FS_TREE_OBJECTID;
301 break;
302 case Opt_device: {
303 struct btrfs_device *device;
304 blk_mode_t mode = btrfs_open_mode(fc);
305
306 mutex_lock(&uuid_mutex);
307 device = btrfs_scan_one_device(param->string, mode, false);
308 mutex_unlock(&uuid_mutex);
309 if (IS_ERR(device))
310 return PTR_ERR(device);
311 break;
312 }
313 case Opt_datasum:
314 if (result.negated) {
315 btrfs_set_opt(ctx->mount_opt, NODATASUM);
316 } else {
317 btrfs_clear_opt(ctx->mount_opt, NODATACOW);
318 btrfs_clear_opt(ctx->mount_opt, NODATASUM);
319 }
320 break;
321 case Opt_datacow:
322 if (result.negated) {
323 btrfs_clear_opt(ctx->mount_opt, COMPRESS);
324 btrfs_clear_opt(ctx->mount_opt, FORCE_COMPRESS);
325 btrfs_set_opt(ctx->mount_opt, NODATACOW);
326 btrfs_set_opt(ctx->mount_opt, NODATASUM);
327 } else {
328 btrfs_clear_opt(ctx->mount_opt, NODATACOW);
329 }
330 break;
331 case Opt_compress_force:
332 case Opt_compress_force_type:
333 btrfs_set_opt(ctx->mount_opt, FORCE_COMPRESS);
334 fallthrough;
335 case Opt_compress:
336 case Opt_compress_type:
337 if (opt == Opt_compress || opt == Opt_compress_force) {
338 ctx->compress_type = BTRFS_COMPRESS_ZLIB;
339 ctx->compress_level = BTRFS_ZLIB_DEFAULT_LEVEL;
340 btrfs_set_opt(ctx->mount_opt, COMPRESS);
341 btrfs_clear_opt(ctx->mount_opt, NODATACOW);
342 btrfs_clear_opt(ctx->mount_opt, NODATASUM);
343 } else if (strncmp(param->string, "zlib", 4) == 0) {
344 ctx->compress_type = BTRFS_COMPRESS_ZLIB;
345 ctx->compress_level =
346 btrfs_compress_str2level(BTRFS_COMPRESS_ZLIB,
347 param->string + 4);
348 btrfs_set_opt(ctx->mount_opt, COMPRESS);
349 btrfs_clear_opt(ctx->mount_opt, NODATACOW);
350 btrfs_clear_opt(ctx->mount_opt, NODATASUM);
351 } else if (strncmp(param->string, "lzo", 3) == 0) {
352 ctx->compress_type = BTRFS_COMPRESS_LZO;
353 ctx->compress_level = 0;
354 btrfs_set_opt(ctx->mount_opt, COMPRESS);
355 btrfs_clear_opt(ctx->mount_opt, NODATACOW);
356 btrfs_clear_opt(ctx->mount_opt, NODATASUM);
357 } else if (strncmp(param->string, "zstd", 4) == 0) {
358 ctx->compress_type = BTRFS_COMPRESS_ZSTD;
359 ctx->compress_level =
360 btrfs_compress_str2level(BTRFS_COMPRESS_ZSTD,
361 param->string + 4);
362 btrfs_set_opt(ctx->mount_opt, COMPRESS);
363 btrfs_clear_opt(ctx->mount_opt, NODATACOW);
364 btrfs_clear_opt(ctx->mount_opt, NODATASUM);
365 } else if (strncmp(param->string, "no", 2) == 0) {
366 ctx->compress_level = 0;
367 ctx->compress_type = 0;
368 btrfs_clear_opt(ctx->mount_opt, COMPRESS);
369 btrfs_clear_opt(ctx->mount_opt, FORCE_COMPRESS);
370 } else {
371 btrfs_err(NULL, "unrecognized compression value %s",
372 param->string);
373 return -EINVAL;
374 }
375 break;
376 case Opt_ssd:
377 if (result.negated) {
378 btrfs_set_opt(ctx->mount_opt, NOSSD);
379 btrfs_clear_opt(ctx->mount_opt, SSD);
380 btrfs_clear_opt(ctx->mount_opt, SSD_SPREAD);
381 } else {
382 btrfs_set_opt(ctx->mount_opt, SSD);
383 btrfs_clear_opt(ctx->mount_opt, NOSSD);
384 }
385 break;
386 case Opt_ssd_spread:
387 if (result.negated) {
388 btrfs_clear_opt(ctx->mount_opt, SSD_SPREAD);
389 } else {
390 btrfs_set_opt(ctx->mount_opt, SSD);
391 btrfs_set_opt(ctx->mount_opt, SSD_SPREAD);
392 btrfs_clear_opt(ctx->mount_opt, NOSSD);
393 }
394 break;
395 case Opt_barrier:
396 if (result.negated)
397 btrfs_set_opt(ctx->mount_opt, NOBARRIER);
398 else
399 btrfs_clear_opt(ctx->mount_opt, NOBARRIER);
400 break;
401 case Opt_thread_pool:
402 if (result.uint_32 == 0) {
403 btrfs_err(NULL, "invalid value 0 for thread_pool");
404 return -EINVAL;
405 }
406 ctx->thread_pool_size = result.uint_32;
407 break;
408 case Opt_max_inline:
409 ctx->max_inline = memparse(param->string, NULL);
410 break;
411 case Opt_acl:
412 if (result.negated) {
413 fc->sb_flags &= ~SB_POSIXACL;
414 } else {
415#ifdef CONFIG_BTRFS_FS_POSIX_ACL
416 fc->sb_flags |= SB_POSIXACL;
417#else
418 btrfs_err(NULL, "support for ACL not compiled in");
419 return -EINVAL;
420#endif
421 }
422 /*
423 * VFS limits the ability to toggle ACL on and off via remount,
424 * despite every file system allowing this. This seems to be
425 * an oversight since we all do, but it'll fail if we're
426 * remounting. So don't set the mask here, we'll check it in
427 * btrfs_reconfigure and do the toggling ourselves.
428 */
429 if (fc->purpose != FS_CONTEXT_FOR_RECONFIGURE)
430 fc->sb_flags_mask |= SB_POSIXACL;
431 break;
432 case Opt_treelog:
433 if (result.negated)
434 btrfs_set_opt(ctx->mount_opt, NOTREELOG);
435 else
436 btrfs_clear_opt(ctx->mount_opt, NOTREELOG);
437 break;
438 case Opt_nologreplay:
439 btrfs_warn(NULL,
440 "'nologreplay' is deprecated, use 'rescue=nologreplay' instead");
441 btrfs_set_opt(ctx->mount_opt, NOLOGREPLAY);
442 break;
443 case Opt_flushoncommit:
444 if (result.negated)
445 btrfs_clear_opt(ctx->mount_opt, FLUSHONCOMMIT);
446 else
447 btrfs_set_opt(ctx->mount_opt, FLUSHONCOMMIT);
448 break;
449 case Opt_ratio:
450 ctx->metadata_ratio = result.uint_32;
451 break;
452 case Opt_discard:
453 if (result.negated) {
454 btrfs_clear_opt(ctx->mount_opt, DISCARD_SYNC);
455 btrfs_clear_opt(ctx->mount_opt, DISCARD_ASYNC);
456 btrfs_set_opt(ctx->mount_opt, NODISCARD);
457 } else {
458 btrfs_set_opt(ctx->mount_opt, DISCARD_SYNC);
459 btrfs_clear_opt(ctx->mount_opt, DISCARD_ASYNC);
460 }
461 break;
462 case Opt_discard_mode:
463 switch (result.uint_32) {
464 case Opt_discard_sync:
465 btrfs_clear_opt(ctx->mount_opt, DISCARD_ASYNC);
466 btrfs_set_opt(ctx->mount_opt, DISCARD_SYNC);
467 break;
468 case Opt_discard_async:
469 btrfs_clear_opt(ctx->mount_opt, DISCARD_SYNC);
470 btrfs_set_opt(ctx->mount_opt, DISCARD_ASYNC);
471 break;
472 default:
473 btrfs_err(NULL, "unrecognized discard mode value %s",
474 param->key);
475 return -EINVAL;
476 }
477 btrfs_clear_opt(ctx->mount_opt, NODISCARD);
478 break;
479 case Opt_space_cache:
480 if (result.negated) {
481 btrfs_set_opt(ctx->mount_opt, NOSPACECACHE);
482 btrfs_clear_opt(ctx->mount_opt, SPACE_CACHE);
483 btrfs_clear_opt(ctx->mount_opt, FREE_SPACE_TREE);
484 } else {
485 btrfs_clear_opt(ctx->mount_opt, FREE_SPACE_TREE);
486 btrfs_set_opt(ctx->mount_opt, SPACE_CACHE);
487 }
488 break;
489 case Opt_space_cache_version:
490 switch (result.uint_32) {
491 case Opt_space_cache_v1:
492 btrfs_set_opt(ctx->mount_opt, SPACE_CACHE);
493 btrfs_clear_opt(ctx->mount_opt, FREE_SPACE_TREE);
494 break;
495 case Opt_space_cache_v2:
496 btrfs_clear_opt(ctx->mount_opt, SPACE_CACHE);
497 btrfs_set_opt(ctx->mount_opt, FREE_SPACE_TREE);
498 break;
499 default:
500 btrfs_err(NULL, "unrecognized space_cache value %s",
501 param->key);
502 return -EINVAL;
503 }
504 break;
505 case Opt_rescan_uuid_tree:
506 btrfs_set_opt(ctx->mount_opt, RESCAN_UUID_TREE);
507 break;
508 case Opt_clear_cache:
509 btrfs_set_opt(ctx->mount_opt, CLEAR_CACHE);
510 break;
511 case Opt_user_subvol_rm_allowed:
512 btrfs_set_opt(ctx->mount_opt, USER_SUBVOL_RM_ALLOWED);
513 break;
514 case Opt_enospc_debug:
515 if (result.negated)
516 btrfs_clear_opt(ctx->mount_opt, ENOSPC_DEBUG);
517 else
518 btrfs_set_opt(ctx->mount_opt, ENOSPC_DEBUG);
519 break;
520 case Opt_defrag:
521 if (result.negated)
522 btrfs_clear_opt(ctx->mount_opt, AUTO_DEFRAG);
523 else
524 btrfs_set_opt(ctx->mount_opt, AUTO_DEFRAG);
525 break;
526 case Opt_usebackuproot:
527 btrfs_warn(NULL,
528 "'usebackuproot' is deprecated, use 'rescue=usebackuproot' instead");
529 btrfs_set_opt(ctx->mount_opt, USEBACKUPROOT);
530
531 /* If we're loading the backup roots we can't trust the space cache. */
532 btrfs_set_opt(ctx->mount_opt, CLEAR_CACHE);
533 break;
534 case Opt_skip_balance:
535 btrfs_set_opt(ctx->mount_opt, SKIP_BALANCE);
536 break;
537 case Opt_fatal_errors:
538 switch (result.uint_32) {
539 case Opt_fatal_errors_panic:
540 btrfs_set_opt(ctx->mount_opt, PANIC_ON_FATAL_ERROR);
541 break;
542 case Opt_fatal_errors_bug:
543 btrfs_clear_opt(ctx->mount_opt, PANIC_ON_FATAL_ERROR);
544 break;
545 default:
546 btrfs_err(NULL, "unrecognized fatal_errors value %s",
547 param->key);
548 return -EINVAL;
549 }
550 break;
551 case Opt_commit_interval:
552 ctx->commit_interval = result.uint_32;
553 if (ctx->commit_interval == 0)
554 ctx->commit_interval = BTRFS_DEFAULT_COMMIT_INTERVAL;
555 break;
556 case Opt_rescue:
557 switch (result.uint_32) {
558 case Opt_rescue_usebackuproot:
559 btrfs_set_opt(ctx->mount_opt, USEBACKUPROOT);
560 break;
561 case Opt_rescue_nologreplay:
562 btrfs_set_opt(ctx->mount_opt, NOLOGREPLAY);
563 break;
564 case Opt_rescue_ignorebadroots:
565 btrfs_set_opt(ctx->mount_opt, IGNOREBADROOTS);
566 break;
567 case Opt_rescue_ignoredatacsums:
568 btrfs_set_opt(ctx->mount_opt, IGNOREDATACSUMS);
569 break;
570 case Opt_rescue_parameter_all:
571 btrfs_set_opt(ctx->mount_opt, IGNOREDATACSUMS);
572 btrfs_set_opt(ctx->mount_opt, IGNOREBADROOTS);
573 btrfs_set_opt(ctx->mount_opt, NOLOGREPLAY);
574 break;
575 default:
576 btrfs_info(NULL, "unrecognized rescue option '%s'",
577 param->key);
578 return -EINVAL;
579 }
580 break;
581#ifdef CONFIG_BTRFS_DEBUG
582 case Opt_fragment:
583 switch (result.uint_32) {
584 case Opt_fragment_parameter_all:
585 btrfs_set_opt(ctx->mount_opt, FRAGMENT_DATA);
586 btrfs_set_opt(ctx->mount_opt, FRAGMENT_METADATA);
587 break;
588 case Opt_fragment_parameter_metadata:
589 btrfs_set_opt(ctx->mount_opt, FRAGMENT_METADATA);
590 break;
591 case Opt_fragment_parameter_data:
592 btrfs_set_opt(ctx->mount_opt, FRAGMENT_DATA);
593 break;
594 default:
595 btrfs_info(NULL, "unrecognized fragment option '%s'",
596 param->key);
597 return -EINVAL;
598 }
599 break;
600#endif
601#ifdef CONFIG_BTRFS_FS_REF_VERIFY
602 case Opt_ref_verify:
603 btrfs_set_opt(ctx->mount_opt, REF_VERIFY);
604 break;
605#endif
606 default:
607 btrfs_err(NULL, "unrecognized mount option '%s'", param->key);
608 return -EINVAL;
609 }
610
611 return 0;
612}
613
614/*
615 * Some options only have meaning at mount time and shouldn't persist across
616 * remounts, or be displayed. Clear these at the end of mount and remount code
617 * paths.
618 */
619static void btrfs_clear_oneshot_options(struct btrfs_fs_info *fs_info)
620{
621 btrfs_clear_opt(fs_info->mount_opt, USEBACKUPROOT);
622 btrfs_clear_opt(fs_info->mount_opt, CLEAR_CACHE);
623 btrfs_clear_opt(fs_info->mount_opt, NOSPACECACHE);
624}
625
626static bool check_ro_option(struct btrfs_fs_info *fs_info,
627 unsigned long mount_opt, unsigned long opt,
628 const char *opt_name)
629{
630 if (mount_opt & opt) {
631 btrfs_err(fs_info, "%s must be used with ro mount option",
632 opt_name);
633 return true;
634 }
635 return false;
636}
637
638bool btrfs_check_options(struct btrfs_fs_info *info, unsigned long *mount_opt,
639 unsigned long flags)
640{
641 bool ret = true;
642
643 if (!(flags & SB_RDONLY) &&
644 (check_ro_option(info, *mount_opt, BTRFS_MOUNT_NOLOGREPLAY, "nologreplay") ||
645 check_ro_option(info, *mount_opt, BTRFS_MOUNT_IGNOREBADROOTS, "ignorebadroots") ||
646 check_ro_option(info, *mount_opt, BTRFS_MOUNT_IGNOREDATACSUMS, "ignoredatacsums")))
647 ret = false;
648
649 if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE) &&
650 !btrfs_raw_test_opt(*mount_opt, FREE_SPACE_TREE) &&
651 !btrfs_raw_test_opt(*mount_opt, CLEAR_CACHE)) {
652 btrfs_err(info, "cannot disable free-space-tree");
653 ret = false;
654 }
655 if (btrfs_fs_compat_ro(info, BLOCK_GROUP_TREE) &&
656 !btrfs_raw_test_opt(*mount_opt, FREE_SPACE_TREE)) {
657 btrfs_err(info, "cannot disable free-space-tree with block-group-tree feature");
658 ret = false;
659 }
660
661 if (btrfs_check_mountopts_zoned(info, mount_opt))
662 ret = false;
663
664 if (!test_bit(BTRFS_FS_STATE_REMOUNTING, &info->fs_state)) {
665 if (btrfs_raw_test_opt(*mount_opt, SPACE_CACHE))
666 btrfs_info(info, "disk space caching is enabled");
667 if (btrfs_raw_test_opt(*mount_opt, FREE_SPACE_TREE))
668 btrfs_info(info, "using free-space-tree");
669 }
670
671 return ret;
672}
673
674/*
675 * This is subtle, we only call this during open_ctree(). We need to pre-load
676 * the mount options with the on-disk settings. Before the new mount API took
677 * effect we would do this on mount and remount. With the new mount API we'll
678 * only do this on the initial mount.
679 *
680 * This isn't a change in behavior, because we're using the current state of the
681 * file system to set the current mount options. If you mounted with special
682 * options to disable these features and then remounted we wouldn't revert the
683 * settings, because mounting without these features cleared the on-disk
684 * settings, so this being called on re-mount is not needed.
685 */
686void btrfs_set_free_space_cache_settings(struct btrfs_fs_info *fs_info)
687{
688 if (fs_info->sectorsize < PAGE_SIZE) {
689 btrfs_clear_opt(fs_info->mount_opt, SPACE_CACHE);
690 if (!btrfs_test_opt(fs_info, FREE_SPACE_TREE)) {
691 btrfs_info(fs_info,
692 "forcing free space tree for sector size %u with page size %lu",
693 fs_info->sectorsize, PAGE_SIZE);
694 btrfs_set_opt(fs_info->mount_opt, FREE_SPACE_TREE);
695 }
696 }
697
698 /*
699 * At this point our mount options are populated, so we only mess with
700 * these settings if we don't have any settings already.
701 */
702 if (btrfs_test_opt(fs_info, FREE_SPACE_TREE))
703 return;
704
705 if (btrfs_is_zoned(fs_info) &&
706 btrfs_free_space_cache_v1_active(fs_info)) {
707 btrfs_info(fs_info, "zoned: clearing existing space cache");
708 btrfs_set_super_cache_generation(fs_info->super_copy, 0);
709 return;
710 }
711
712 if (btrfs_test_opt(fs_info, SPACE_CACHE))
713 return;
714
715 if (btrfs_test_opt(fs_info, NOSPACECACHE))
716 return;
717
718 /*
719 * At this point we don't have explicit options set by the user, set
720 * them ourselves based on the state of the file system.
721 */
722 if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
723 btrfs_set_opt(fs_info->mount_opt, FREE_SPACE_TREE);
724 else if (btrfs_free_space_cache_v1_active(fs_info))
725 btrfs_set_opt(fs_info->mount_opt, SPACE_CACHE);
726}
727
728static void set_device_specific_options(struct btrfs_fs_info *fs_info)
729{
730 if (!btrfs_test_opt(fs_info, NOSSD) &&
731 !fs_info->fs_devices->rotating)
732 btrfs_set_opt(fs_info->mount_opt, SSD);
733
734 /*
735 * For devices supporting discard turn on discard=async automatically,
736 * unless it's already set or disabled. This could be turned off by
737 * nodiscard for the same mount.
738 *
739 * The zoned mode piggy backs on the discard functionality for
740 * resetting a zone. There is no reason to delay the zone reset as it is
741 * fast enough. So, do not enable async discard for zoned mode.
742 */
743 if (!(btrfs_test_opt(fs_info, DISCARD_SYNC) ||
744 btrfs_test_opt(fs_info, DISCARD_ASYNC) ||
745 btrfs_test_opt(fs_info, NODISCARD)) &&
746 fs_info->fs_devices->discardable &&
747 !btrfs_is_zoned(fs_info))
748 btrfs_set_opt(fs_info->mount_opt, DISCARD_ASYNC);
749}
750
751char *btrfs_get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
752 u64 subvol_objectid)
753{
754 struct btrfs_root *root = fs_info->tree_root;
755 struct btrfs_root *fs_root = NULL;
756 struct btrfs_root_ref *root_ref;
757 struct btrfs_inode_ref *inode_ref;
758 struct btrfs_key key;
759 struct btrfs_path *path = NULL;
760 char *name = NULL, *ptr;
761 u64 dirid;
762 int len;
763 int ret;
764
765 path = btrfs_alloc_path();
766 if (!path) {
767 ret = -ENOMEM;
768 goto err;
769 }
770
771 name = kmalloc(PATH_MAX, GFP_KERNEL);
772 if (!name) {
773 ret = -ENOMEM;
774 goto err;
775 }
776 ptr = name + PATH_MAX - 1;
777 ptr[0] = '\0';
778
779 /*
780 * Walk up the subvolume trees in the tree of tree roots by root
781 * backrefs until we hit the top-level subvolume.
782 */
783 while (subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
784 key.objectid = subvol_objectid;
785 key.type = BTRFS_ROOT_BACKREF_KEY;
786 key.offset = (u64)-1;
787
788 ret = btrfs_search_backwards(root, &key, path);
789 if (ret < 0) {
790 goto err;
791 } else if (ret > 0) {
792 ret = -ENOENT;
793 goto err;
794 }
795
796 subvol_objectid = key.offset;
797
798 root_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
799 struct btrfs_root_ref);
800 len = btrfs_root_ref_name_len(path->nodes[0], root_ref);
801 ptr -= len + 1;
802 if (ptr < name) {
803 ret = -ENAMETOOLONG;
804 goto err;
805 }
806 read_extent_buffer(path->nodes[0], ptr + 1,
807 (unsigned long)(root_ref + 1), len);
808 ptr[0] = '/';
809 dirid = btrfs_root_ref_dirid(path->nodes[0], root_ref);
810 btrfs_release_path(path);
811
812 fs_root = btrfs_get_fs_root(fs_info, subvol_objectid, true);
813 if (IS_ERR(fs_root)) {
814 ret = PTR_ERR(fs_root);
815 fs_root = NULL;
816 goto err;
817 }
818
819 /*
820 * Walk up the filesystem tree by inode refs until we hit the
821 * root directory.
822 */
823 while (dirid != BTRFS_FIRST_FREE_OBJECTID) {
824 key.objectid = dirid;
825 key.type = BTRFS_INODE_REF_KEY;
826 key.offset = (u64)-1;
827
828 ret = btrfs_search_backwards(fs_root, &key, path);
829 if (ret < 0) {
830 goto err;
831 } else if (ret > 0) {
832 ret = -ENOENT;
833 goto err;
834 }
835
836 dirid = key.offset;
837
838 inode_ref = btrfs_item_ptr(path->nodes[0],
839 path->slots[0],
840 struct btrfs_inode_ref);
841 len = btrfs_inode_ref_name_len(path->nodes[0],
842 inode_ref);
843 ptr -= len + 1;
844 if (ptr < name) {
845 ret = -ENAMETOOLONG;
846 goto err;
847 }
848 read_extent_buffer(path->nodes[0], ptr + 1,
849 (unsigned long)(inode_ref + 1), len);
850 ptr[0] = '/';
851 btrfs_release_path(path);
852 }
853 btrfs_put_root(fs_root);
854 fs_root = NULL;
855 }
856
857 btrfs_free_path(path);
858 if (ptr == name + PATH_MAX - 1) {
859 name[0] = '/';
860 name[1] = '\0';
861 } else {
862 memmove(name, ptr, name + PATH_MAX - ptr);
863 }
864 return name;
865
866err:
867 btrfs_put_root(fs_root);
868 btrfs_free_path(path);
869 kfree(name);
870 return ERR_PTR(ret);
871}
872
873static int get_default_subvol_objectid(struct btrfs_fs_info *fs_info, u64 *objectid)
874{
875 struct btrfs_root *root = fs_info->tree_root;
876 struct btrfs_dir_item *di;
877 struct btrfs_path *path;
878 struct btrfs_key location;
879 struct fscrypt_str name = FSTR_INIT("default", 7);
880 u64 dir_id;
881
882 path = btrfs_alloc_path();
883 if (!path)
884 return -ENOMEM;
885
886 /*
887 * Find the "default" dir item which points to the root item that we
888 * will mount by default if we haven't been given a specific subvolume
889 * to mount.
890 */
891 dir_id = btrfs_super_root_dir(fs_info->super_copy);
892 di = btrfs_lookup_dir_item(NULL, root, path, dir_id, &name, 0);
893 if (IS_ERR(di)) {
894 btrfs_free_path(path);
895 return PTR_ERR(di);
896 }
897 if (!di) {
898 /*
899 * Ok the default dir item isn't there. This is weird since
900 * it's always been there, but don't freak out, just try and
901 * mount the top-level subvolume.
902 */
903 btrfs_free_path(path);
904 *objectid = BTRFS_FS_TREE_OBJECTID;
905 return 0;
906 }
907
908 btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
909 btrfs_free_path(path);
910 *objectid = location.objectid;
911 return 0;
912}
913
914static int btrfs_fill_super(struct super_block *sb,
915 struct btrfs_fs_devices *fs_devices,
916 void *data)
917{
918 struct inode *inode;
919 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
920 int err;
921
922 sb->s_maxbytes = MAX_LFS_FILESIZE;
923 sb->s_magic = BTRFS_SUPER_MAGIC;
924 sb->s_op = &btrfs_super_ops;
925 sb->s_d_op = &btrfs_dentry_operations;
926 sb->s_export_op = &btrfs_export_ops;
927#ifdef CONFIG_FS_VERITY
928 sb->s_vop = &btrfs_verityops;
929#endif
930 sb->s_xattr = btrfs_xattr_handlers;
931 sb->s_time_gran = 1;
932 sb->s_iflags |= SB_I_CGROUPWB;
933
934 err = super_setup_bdi(sb);
935 if (err) {
936 btrfs_err(fs_info, "super_setup_bdi failed");
937 return err;
938 }
939
940 err = open_ctree(sb, fs_devices, (char *)data);
941 if (err) {
942 btrfs_err(fs_info, "open_ctree failed");
943 return err;
944 }
945
946 inode = btrfs_iget(sb, BTRFS_FIRST_FREE_OBJECTID, fs_info->fs_root);
947 if (IS_ERR(inode)) {
948 err = PTR_ERR(inode);
949 btrfs_handle_fs_error(fs_info, err, NULL);
950 goto fail_close;
951 }
952
953 sb->s_root = d_make_root(inode);
954 if (!sb->s_root) {
955 err = -ENOMEM;
956 goto fail_close;
957 }
958
959 sb->s_flags |= SB_ACTIVE;
960 return 0;
961
962fail_close:
963 close_ctree(fs_info);
964 return err;
965}
966
967int btrfs_sync_fs(struct super_block *sb, int wait)
968{
969 struct btrfs_trans_handle *trans;
970 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
971 struct btrfs_root *root = fs_info->tree_root;
972
973 trace_btrfs_sync_fs(fs_info, wait);
974
975 if (!wait) {
976 filemap_flush(fs_info->btree_inode->i_mapping);
977 return 0;
978 }
979
980 btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
981
982 trans = btrfs_attach_transaction_barrier(root);
983 if (IS_ERR(trans)) {
984 /* no transaction, don't bother */
985 if (PTR_ERR(trans) == -ENOENT) {
986 /*
987 * Exit unless we have some pending changes
988 * that need to go through commit
989 */
990 if (!test_bit(BTRFS_FS_NEED_TRANS_COMMIT,
991 &fs_info->flags))
992 return 0;
993 /*
994 * A non-blocking test if the fs is frozen. We must not
995 * start a new transaction here otherwise a deadlock
996 * happens. The pending operations are delayed to the
997 * next commit after thawing.
998 */
999 if (sb_start_write_trylock(sb))
1000 sb_end_write(sb);
1001 else
1002 return 0;
1003 trans = btrfs_start_transaction(root, 0);
1004 }
1005 if (IS_ERR(trans))
1006 return PTR_ERR(trans);
1007 }
1008 return btrfs_commit_transaction(trans);
1009}
1010
1011static void print_rescue_option(struct seq_file *seq, const char *s, bool *printed)
1012{
1013 seq_printf(seq, "%s%s", (*printed) ? ":" : ",rescue=", s);
1014 *printed = true;
1015}
1016
1017static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
1018{
1019 struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
1020 const char *compress_type;
1021 const char *subvol_name;
1022 bool printed = false;
1023
1024 if (btrfs_test_opt(info, DEGRADED))
1025 seq_puts(seq, ",degraded");
1026 if (btrfs_test_opt(info, NODATASUM))
1027 seq_puts(seq, ",nodatasum");
1028 if (btrfs_test_opt(info, NODATACOW))
1029 seq_puts(seq, ",nodatacow");
1030 if (btrfs_test_opt(info, NOBARRIER))
1031 seq_puts(seq, ",nobarrier");
1032 if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE)
1033 seq_printf(seq, ",max_inline=%llu", info->max_inline);
1034 if (info->thread_pool_size != min_t(unsigned long,
1035 num_online_cpus() + 2, 8))
1036 seq_printf(seq, ",thread_pool=%u", info->thread_pool_size);
1037 if (btrfs_test_opt(info, COMPRESS)) {
1038 compress_type = btrfs_compress_type2str(info->compress_type);
1039 if (btrfs_test_opt(info, FORCE_COMPRESS))
1040 seq_printf(seq, ",compress-force=%s", compress_type);
1041 else
1042 seq_printf(seq, ",compress=%s", compress_type);
1043 if (info->compress_level)
1044 seq_printf(seq, ":%d", info->compress_level);
1045 }
1046 if (btrfs_test_opt(info, NOSSD))
1047 seq_puts(seq, ",nossd");
1048 if (btrfs_test_opt(info, SSD_SPREAD))
1049 seq_puts(seq, ",ssd_spread");
1050 else if (btrfs_test_opt(info, SSD))
1051 seq_puts(seq, ",ssd");
1052 if (btrfs_test_opt(info, NOTREELOG))
1053 seq_puts(seq, ",notreelog");
1054 if (btrfs_test_opt(info, NOLOGREPLAY))
1055 print_rescue_option(seq, "nologreplay", &printed);
1056 if (btrfs_test_opt(info, USEBACKUPROOT))
1057 print_rescue_option(seq, "usebackuproot", &printed);
1058 if (btrfs_test_opt(info, IGNOREBADROOTS))
1059 print_rescue_option(seq, "ignorebadroots", &printed);
1060 if (btrfs_test_opt(info, IGNOREDATACSUMS))
1061 print_rescue_option(seq, "ignoredatacsums", &printed);
1062 if (btrfs_test_opt(info, FLUSHONCOMMIT))
1063 seq_puts(seq, ",flushoncommit");
1064 if (btrfs_test_opt(info, DISCARD_SYNC))
1065 seq_puts(seq, ",discard");
1066 if (btrfs_test_opt(info, DISCARD_ASYNC))
1067 seq_puts(seq, ",discard=async");
1068 if (!(info->sb->s_flags & SB_POSIXACL))
1069 seq_puts(seq, ",noacl");
1070 if (btrfs_free_space_cache_v1_active(info))
1071 seq_puts(seq, ",space_cache");
1072 else if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE))
1073 seq_puts(seq, ",space_cache=v2");
1074 else
1075 seq_puts(seq, ",nospace_cache");
1076 if (btrfs_test_opt(info, RESCAN_UUID_TREE))
1077 seq_puts(seq, ",rescan_uuid_tree");
1078 if (btrfs_test_opt(info, CLEAR_CACHE))
1079 seq_puts(seq, ",clear_cache");
1080 if (btrfs_test_opt(info, USER_SUBVOL_RM_ALLOWED))
1081 seq_puts(seq, ",user_subvol_rm_allowed");
1082 if (btrfs_test_opt(info, ENOSPC_DEBUG))
1083 seq_puts(seq, ",enospc_debug");
1084 if (btrfs_test_opt(info, AUTO_DEFRAG))
1085 seq_puts(seq, ",autodefrag");
1086 if (btrfs_test_opt(info, SKIP_BALANCE))
1087 seq_puts(seq, ",skip_balance");
1088 if (info->metadata_ratio)
1089 seq_printf(seq, ",metadata_ratio=%u", info->metadata_ratio);
1090 if (btrfs_test_opt(info, PANIC_ON_FATAL_ERROR))
1091 seq_puts(seq, ",fatal_errors=panic");
1092 if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL)
1093 seq_printf(seq, ",commit=%u", info->commit_interval);
1094#ifdef CONFIG_BTRFS_DEBUG
1095 if (btrfs_test_opt(info, FRAGMENT_DATA))
1096 seq_puts(seq, ",fragment=data");
1097 if (btrfs_test_opt(info, FRAGMENT_METADATA))
1098 seq_puts(seq, ",fragment=metadata");
1099#endif
1100 if (btrfs_test_opt(info, REF_VERIFY))
1101 seq_puts(seq, ",ref_verify");
1102 seq_printf(seq, ",subvolid=%llu",
1103 BTRFS_I(d_inode(dentry))->root->root_key.objectid);
1104 subvol_name = btrfs_get_subvol_name_from_objectid(info,
1105 BTRFS_I(d_inode(dentry))->root->root_key.objectid);
1106 if (!IS_ERR(subvol_name)) {
1107 seq_puts(seq, ",subvol=");
1108 seq_escape(seq, subvol_name, " \t\n\\");
1109 kfree(subvol_name);
1110 }
1111 return 0;
1112}
1113
1114/*
1115 * subvolumes are identified by ino 256
1116 */
1117static inline int is_subvolume_inode(struct inode *inode)
1118{
1119 if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
1120 return 1;
1121 return 0;
1122}
1123
1124static struct dentry *mount_subvol(const char *subvol_name, u64 subvol_objectid,
1125 struct vfsmount *mnt)
1126{
1127 struct dentry *root;
1128 int ret;
1129
1130 if (!subvol_name) {
1131 if (!subvol_objectid) {
1132 ret = get_default_subvol_objectid(btrfs_sb(mnt->mnt_sb),
1133 &subvol_objectid);
1134 if (ret) {
1135 root = ERR_PTR(ret);
1136 goto out;
1137 }
1138 }
1139 subvol_name = btrfs_get_subvol_name_from_objectid(
1140 btrfs_sb(mnt->mnt_sb), subvol_objectid);
1141 if (IS_ERR(subvol_name)) {
1142 root = ERR_CAST(subvol_name);
1143 subvol_name = NULL;
1144 goto out;
1145 }
1146
1147 }
1148
1149 root = mount_subtree(mnt, subvol_name);
1150 /* mount_subtree() drops our reference on the vfsmount. */
1151 mnt = NULL;
1152
1153 if (!IS_ERR(root)) {
1154 struct super_block *s = root->d_sb;
1155 struct btrfs_fs_info *fs_info = btrfs_sb(s);
1156 struct inode *root_inode = d_inode(root);
1157 u64 root_objectid = BTRFS_I(root_inode)->root->root_key.objectid;
1158
1159 ret = 0;
1160 if (!is_subvolume_inode(root_inode)) {
1161 btrfs_err(fs_info, "'%s' is not a valid subvolume",
1162 subvol_name);
1163 ret = -EINVAL;
1164 }
1165 if (subvol_objectid && root_objectid != subvol_objectid) {
1166 /*
1167 * This will also catch a race condition where a
1168 * subvolume which was passed by ID is renamed and
1169 * another subvolume is renamed over the old location.
1170 */
1171 btrfs_err(fs_info,
1172 "subvol '%s' does not match subvolid %llu",
1173 subvol_name, subvol_objectid);
1174 ret = -EINVAL;
1175 }
1176 if (ret) {
1177 dput(root);
1178 root = ERR_PTR(ret);
1179 deactivate_locked_super(s);
1180 }
1181 }
1182
1183out:
1184 mntput(mnt);
1185 kfree(subvol_name);
1186 return root;
1187}
1188
1189static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
1190 u32 new_pool_size, u32 old_pool_size)
1191{
1192 if (new_pool_size == old_pool_size)
1193 return;
1194
1195 fs_info->thread_pool_size = new_pool_size;
1196
1197 btrfs_info(fs_info, "resize thread pool %d -> %d",
1198 old_pool_size, new_pool_size);
1199
1200 btrfs_workqueue_set_max(fs_info->workers, new_pool_size);
1201 btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size);
1202 btrfs_workqueue_set_max(fs_info->caching_workers, new_pool_size);
1203 workqueue_set_max_active(fs_info->endio_workers, new_pool_size);
1204 workqueue_set_max_active(fs_info->endio_meta_workers, new_pool_size);
1205 btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size);
1206 btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
1207 btrfs_workqueue_set_max(fs_info->delayed_workers, new_pool_size);
1208}
1209
1210static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info,
1211 unsigned long old_opts, int flags)
1212{
1213 if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1214 (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1215 (flags & SB_RDONLY))) {
1216 /* wait for any defraggers to finish */
1217 wait_event(fs_info->transaction_wait,
1218 (atomic_read(&fs_info->defrag_running) == 0));
1219 if (flags & SB_RDONLY)
1220 sync_filesystem(fs_info->sb);
1221 }
1222}
1223
1224static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
1225 unsigned long old_opts)
1226{
1227 const bool cache_opt = btrfs_test_opt(fs_info, SPACE_CACHE);
1228
1229 /*
1230 * We need to cleanup all defragable inodes if the autodefragment is
1231 * close or the filesystem is read only.
1232 */
1233 if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1234 (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) || sb_rdonly(fs_info->sb))) {
1235 btrfs_cleanup_defrag_inodes(fs_info);
1236 }
1237
1238 /* If we toggled discard async */
1239 if (!btrfs_raw_test_opt(old_opts, DISCARD_ASYNC) &&
1240 btrfs_test_opt(fs_info, DISCARD_ASYNC))
1241 btrfs_discard_resume(fs_info);
1242 else if (btrfs_raw_test_opt(old_opts, DISCARD_ASYNC) &&
1243 !btrfs_test_opt(fs_info, DISCARD_ASYNC))
1244 btrfs_discard_cleanup(fs_info);
1245
1246 /* If we toggled space cache */
1247 if (cache_opt != btrfs_free_space_cache_v1_active(fs_info))
1248 btrfs_set_free_space_cache_v1_active(fs_info, cache_opt);
1249}
1250
1251static int btrfs_remount_rw(struct btrfs_fs_info *fs_info)
1252{
1253 int ret;
1254
1255 if (BTRFS_FS_ERROR(fs_info)) {
1256 btrfs_err(fs_info,
1257 "remounting read-write after error is not allowed");
1258 return -EINVAL;
1259 }
1260
1261 if (fs_info->fs_devices->rw_devices == 0)
1262 return -EACCES;
1263
1264 if (!btrfs_check_rw_degradable(fs_info, NULL)) {
1265 btrfs_warn(fs_info,
1266 "too many missing devices, writable remount is not allowed");
1267 return -EACCES;
1268 }
1269
1270 if (btrfs_super_log_root(fs_info->super_copy) != 0) {
1271 btrfs_warn(fs_info,
1272 "mount required to replay tree-log, cannot remount read-write");
1273 return -EINVAL;
1274 }
1275
1276 /*
1277 * NOTE: when remounting with a change that does writes, don't put it
1278 * anywhere above this point, as we are not sure to be safe to write
1279 * until we pass the above checks.
1280 */
1281 ret = btrfs_start_pre_rw_mount(fs_info);
1282 if (ret)
1283 return ret;
1284
1285 btrfs_clear_sb_rdonly(fs_info->sb);
1286
1287 set_bit(BTRFS_FS_OPEN, &fs_info->flags);
1288
1289 /*
1290 * If we've gone from readonly -> read-write, we need to get our
1291 * sync/async discard lists in the right state.
1292 */
1293 btrfs_discard_resume(fs_info);
1294
1295 return 0;
1296}
1297
1298static int btrfs_remount_ro(struct btrfs_fs_info *fs_info)
1299{
1300 /*
1301 * This also happens on 'umount -rf' or on shutdown, when the
1302 * filesystem is busy.
1303 */
1304 cancel_work_sync(&fs_info->async_reclaim_work);
1305 cancel_work_sync(&fs_info->async_data_reclaim_work);
1306
1307 btrfs_discard_cleanup(fs_info);
1308
1309 /* Wait for the uuid_scan task to finish */
1310 down(&fs_info->uuid_tree_rescan_sem);
1311 /* Avoid complains from lockdep et al. */
1312 up(&fs_info->uuid_tree_rescan_sem);
1313
1314 btrfs_set_sb_rdonly(fs_info->sb);
1315
1316 /*
1317 * Setting SB_RDONLY will put the cleaner thread to sleep at the next
1318 * loop if it's already active. If it's already asleep, we'll leave
1319 * unused block groups on disk until we're mounted read-write again
1320 * unless we clean them up here.
1321 */
1322 btrfs_delete_unused_bgs(fs_info);
1323
1324 /*
1325 * The cleaner task could be already running before we set the flag
1326 * BTRFS_FS_STATE_RO (and SB_RDONLY in the superblock). We must make
1327 * sure that after we finish the remount, i.e. after we call
1328 * btrfs_commit_super(), the cleaner can no longer start a transaction
1329 * - either because it was dropping a dead root, running delayed iputs
1330 * or deleting an unused block group (the cleaner picked a block
1331 * group from the list of unused block groups before we were able to
1332 * in the previous call to btrfs_delete_unused_bgs()).
1333 */
1334 wait_on_bit(&fs_info->flags, BTRFS_FS_CLEANER_RUNNING, TASK_UNINTERRUPTIBLE);
1335
1336 /*
1337 * We've set the superblock to RO mode, so we might have made the
1338 * cleaner task sleep without running all pending delayed iputs. Go
1339 * through all the delayed iputs here, so that if an unmount happens
1340 * without remounting RW we don't end up at finishing close_ctree()
1341 * with a non-empty list of delayed iputs.
1342 */
1343 btrfs_run_delayed_iputs(fs_info);
1344
1345 btrfs_dev_replace_suspend_for_unmount(fs_info);
1346 btrfs_scrub_cancel(fs_info);
1347 btrfs_pause_balance(fs_info);
1348
1349 /*
1350 * Pause the qgroup rescan worker if it is running. We don't want it to
1351 * be still running after we are in RO mode, as after that, by the time
1352 * we unmount, it might have left a transaction open, so we would leak
1353 * the transaction and/or crash.
1354 */
1355 btrfs_qgroup_wait_for_completion(fs_info, false);
1356
1357 return btrfs_commit_super(fs_info);
1358}
1359
1360static void btrfs_ctx_to_info(struct btrfs_fs_info *fs_info, struct btrfs_fs_context *ctx)
1361{
1362 fs_info->max_inline = ctx->max_inline;
1363 fs_info->commit_interval = ctx->commit_interval;
1364 fs_info->metadata_ratio = ctx->metadata_ratio;
1365 fs_info->thread_pool_size = ctx->thread_pool_size;
1366 fs_info->mount_opt = ctx->mount_opt;
1367 fs_info->compress_type = ctx->compress_type;
1368 fs_info->compress_level = ctx->compress_level;
1369}
1370
1371static void btrfs_info_to_ctx(struct btrfs_fs_info *fs_info, struct btrfs_fs_context *ctx)
1372{
1373 ctx->max_inline = fs_info->max_inline;
1374 ctx->commit_interval = fs_info->commit_interval;
1375 ctx->metadata_ratio = fs_info->metadata_ratio;
1376 ctx->thread_pool_size = fs_info->thread_pool_size;
1377 ctx->mount_opt = fs_info->mount_opt;
1378 ctx->compress_type = fs_info->compress_type;
1379 ctx->compress_level = fs_info->compress_level;
1380}
1381
1382#define btrfs_info_if_set(fs_info, old_ctx, opt, fmt, args...) \
1383do { \
1384 if ((!old_ctx || !btrfs_raw_test_opt(old_ctx->mount_opt, opt)) && \
1385 btrfs_raw_test_opt(fs_info->mount_opt, opt)) \
1386 btrfs_info(fs_info, fmt, ##args); \
1387} while (0)
1388
1389#define btrfs_info_if_unset(fs_info, old_ctx, opt, fmt, args...) \
1390do { \
1391 if ((old_ctx && btrfs_raw_test_opt(old_ctx->mount_opt, opt)) && \
1392 !btrfs_raw_test_opt(fs_info->mount_opt, opt)) \
1393 btrfs_info(fs_info, fmt, ##args); \
1394} while (0)
1395
1396static void btrfs_emit_options(struct btrfs_fs_info *info,
1397 struct btrfs_fs_context *old)
1398{
1399 btrfs_info_if_set(info, old, NODATASUM, "setting nodatasum");
1400 btrfs_info_if_set(info, old, DEGRADED, "allowing degraded mounts");
1401 btrfs_info_if_set(info, old, NODATASUM, "setting nodatasum");
1402 btrfs_info_if_set(info, old, SSD, "enabling ssd optimizations");
1403 btrfs_info_if_set(info, old, SSD_SPREAD, "using spread ssd allocation scheme");
1404 btrfs_info_if_set(info, old, NOBARRIER, "turning off barriers");
1405 btrfs_info_if_set(info, old, NOTREELOG, "disabling tree log");
1406 btrfs_info_if_set(info, old, NOLOGREPLAY, "disabling log replay at mount time");
1407 btrfs_info_if_set(info, old, FLUSHONCOMMIT, "turning on flush-on-commit");
1408 btrfs_info_if_set(info, old, DISCARD_SYNC, "turning on sync discard");
1409 btrfs_info_if_set(info, old, DISCARD_ASYNC, "turning on async discard");
1410 btrfs_info_if_set(info, old, FREE_SPACE_TREE, "enabling free space tree");
1411 btrfs_info_if_set(info, old, SPACE_CACHE, "enabling disk space caching");
1412 btrfs_info_if_set(info, old, CLEAR_CACHE, "force clearing of disk cache");
1413 btrfs_info_if_set(info, old, AUTO_DEFRAG, "enabling auto defrag");
1414 btrfs_info_if_set(info, old, FRAGMENT_DATA, "fragmenting data");
1415 btrfs_info_if_set(info, old, FRAGMENT_METADATA, "fragmenting metadata");
1416 btrfs_info_if_set(info, old, REF_VERIFY, "doing ref verification");
1417 btrfs_info_if_set(info, old, USEBACKUPROOT, "trying to use backup root at mount time");
1418 btrfs_info_if_set(info, old, IGNOREBADROOTS, "ignoring bad roots");
1419 btrfs_info_if_set(info, old, IGNOREDATACSUMS, "ignoring data csums");
1420
1421 btrfs_info_if_unset(info, old, NODATACOW, "setting datacow");
1422 btrfs_info_if_unset(info, old, SSD, "not using ssd optimizations");
1423 btrfs_info_if_unset(info, old, SSD_SPREAD, "not using spread ssd allocation scheme");
1424 btrfs_info_if_unset(info, old, NOBARRIER, "turning off barriers");
1425 btrfs_info_if_unset(info, old, NOTREELOG, "enabling tree log");
1426 btrfs_info_if_unset(info, old, SPACE_CACHE, "disabling disk space caching");
1427 btrfs_info_if_unset(info, old, FREE_SPACE_TREE, "disabling free space tree");
1428 btrfs_info_if_unset(info, old, AUTO_DEFRAG, "disabling auto defrag");
1429 btrfs_info_if_unset(info, old, COMPRESS, "use no compression");
1430
1431 /* Did the compression settings change? */
1432 if (btrfs_test_opt(info, COMPRESS) &&
1433 (!old ||
1434 old->compress_type != info->compress_type ||
1435 old->compress_level != info->compress_level ||
1436 (!btrfs_raw_test_opt(old->mount_opt, FORCE_COMPRESS) &&
1437 btrfs_raw_test_opt(info->mount_opt, FORCE_COMPRESS)))) {
1438 const char *compress_type = btrfs_compress_type2str(info->compress_type);
1439
1440 btrfs_info(info, "%s %s compression, level %d",
1441 btrfs_test_opt(info, FORCE_COMPRESS) ? "force" : "use",
1442 compress_type, info->compress_level);
1443 }
1444
1445 if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE)
1446 btrfs_info(info, "max_inline set to %llu", info->max_inline);
1447}
1448
1449static int btrfs_reconfigure(struct fs_context *fc)
1450{
1451 struct super_block *sb = fc->root->d_sb;
1452 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1453 struct btrfs_fs_context *ctx = fc->fs_private;
1454 struct btrfs_fs_context old_ctx;
1455 int ret = 0;
1456 bool mount_reconfigure = (fc->s_fs_info != NULL);
1457
1458 btrfs_info_to_ctx(fs_info, &old_ctx);
1459
1460 /*
1461 * This is our "bind mount" trick, we don't want to allow the user to do
1462 * anything other than mount a different ro/rw and a different subvol,
1463 * all of the mount options should be maintained.
1464 */
1465 if (mount_reconfigure)
1466 ctx->mount_opt = old_ctx.mount_opt;
1467
1468 sync_filesystem(sb);
1469 set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1470
1471 if (!mount_reconfigure &&
1472 !btrfs_check_options(fs_info, &ctx->mount_opt, fc->sb_flags))
1473 return -EINVAL;
1474
1475 ret = btrfs_check_features(fs_info, !(fc->sb_flags & SB_RDONLY));
1476 if (ret < 0)
1477 return ret;
1478
1479 btrfs_ctx_to_info(fs_info, ctx);
1480 btrfs_remount_begin(fs_info, old_ctx.mount_opt, fc->sb_flags);
1481 btrfs_resize_thread_pool(fs_info, fs_info->thread_pool_size,
1482 old_ctx.thread_pool_size);
1483
1484 if ((bool)btrfs_test_opt(fs_info, FREE_SPACE_TREE) !=
1485 (bool)btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE) &&
1486 (!sb_rdonly(sb) || (fc->sb_flags & SB_RDONLY))) {
1487 btrfs_warn(fs_info,
1488 "remount supports changing free space tree only from RO to RW");
1489 /* Make sure free space cache options match the state on disk. */
1490 if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE)) {
1491 btrfs_set_opt(fs_info->mount_opt, FREE_SPACE_TREE);
1492 btrfs_clear_opt(fs_info->mount_opt, SPACE_CACHE);
1493 }
1494 if (btrfs_free_space_cache_v1_active(fs_info)) {
1495 btrfs_clear_opt(fs_info->mount_opt, FREE_SPACE_TREE);
1496 btrfs_set_opt(fs_info->mount_opt, SPACE_CACHE);
1497 }
1498 }
1499
1500 ret = 0;
1501 if (!sb_rdonly(sb) && (fc->sb_flags & SB_RDONLY))
1502 ret = btrfs_remount_ro(fs_info);
1503 else if (sb_rdonly(sb) && !(fc->sb_flags & SB_RDONLY))
1504 ret = btrfs_remount_rw(fs_info);
1505 if (ret)
1506 goto restore;
1507
1508 /*
1509 * If we set the mask during the parameter parsing VFS would reject the
1510 * remount. Here we can set the mask and the value will be updated
1511 * appropriately.
1512 */
1513 if ((fc->sb_flags & SB_POSIXACL) != (sb->s_flags & SB_POSIXACL))
1514 fc->sb_flags_mask |= SB_POSIXACL;
1515
1516 btrfs_emit_options(fs_info, &old_ctx);
1517 wake_up_process(fs_info->transaction_kthread);
1518 btrfs_remount_cleanup(fs_info, old_ctx.mount_opt);
1519 btrfs_clear_oneshot_options(fs_info);
1520 clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1521
1522 return 0;
1523restore:
1524 btrfs_ctx_to_info(fs_info, &old_ctx);
1525 btrfs_remount_cleanup(fs_info, old_ctx.mount_opt);
1526 clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1527 return ret;
1528}
1529
1530/* Used to sort the devices by max_avail(descending sort) */
1531static int btrfs_cmp_device_free_bytes(const void *a, const void *b)
1532{
1533 const struct btrfs_device_info *dev_info1 = a;
1534 const struct btrfs_device_info *dev_info2 = b;
1535
1536 if (dev_info1->max_avail > dev_info2->max_avail)
1537 return -1;
1538 else if (dev_info1->max_avail < dev_info2->max_avail)
1539 return 1;
1540 return 0;
1541}
1542
1543/*
1544 * sort the devices by max_avail, in which max free extent size of each device
1545 * is stored.(Descending Sort)
1546 */
1547static inline void btrfs_descending_sort_devices(
1548 struct btrfs_device_info *devices,
1549 size_t nr_devices)
1550{
1551 sort(devices, nr_devices, sizeof(struct btrfs_device_info),
1552 btrfs_cmp_device_free_bytes, NULL);
1553}
1554
1555/*
1556 * The helper to calc the free space on the devices that can be used to store
1557 * file data.
1558 */
1559static inline int btrfs_calc_avail_data_space(struct btrfs_fs_info *fs_info,
1560 u64 *free_bytes)
1561{
1562 struct btrfs_device_info *devices_info;
1563 struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
1564 struct btrfs_device *device;
1565 u64 type;
1566 u64 avail_space;
1567 u64 min_stripe_size;
1568 int num_stripes = 1;
1569 int i = 0, nr_devices;
1570 const struct btrfs_raid_attr *rattr;
1571
1572 /*
1573 * We aren't under the device list lock, so this is racy-ish, but good
1574 * enough for our purposes.
1575 */
1576 nr_devices = fs_info->fs_devices->open_devices;
1577 if (!nr_devices) {
1578 smp_mb();
1579 nr_devices = fs_info->fs_devices->open_devices;
1580 ASSERT(nr_devices);
1581 if (!nr_devices) {
1582 *free_bytes = 0;
1583 return 0;
1584 }
1585 }
1586
1587 devices_info = kmalloc_array(nr_devices, sizeof(*devices_info),
1588 GFP_KERNEL);
1589 if (!devices_info)
1590 return -ENOMEM;
1591
1592 /* calc min stripe number for data space allocation */
1593 type = btrfs_data_alloc_profile(fs_info);
1594 rattr = &btrfs_raid_array[btrfs_bg_flags_to_raid_index(type)];
1595
1596 if (type & BTRFS_BLOCK_GROUP_RAID0)
1597 num_stripes = nr_devices;
1598 else if (type & BTRFS_BLOCK_GROUP_RAID1_MASK)
1599 num_stripes = rattr->ncopies;
1600 else if (type & BTRFS_BLOCK_GROUP_RAID10)
1601 num_stripes = 4;
1602
1603 /* Adjust for more than 1 stripe per device */
1604 min_stripe_size = rattr->dev_stripes * BTRFS_STRIPE_LEN;
1605
1606 rcu_read_lock();
1607 list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
1608 if (!test_bit(BTRFS_DEV_STATE_IN_FS_METADATA,
1609 &device->dev_state) ||
1610 !device->bdev ||
1611 test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state))
1612 continue;
1613
1614 if (i >= nr_devices)
1615 break;
1616
1617 avail_space = device->total_bytes - device->bytes_used;
1618
1619 /* align with stripe_len */
1620 avail_space = rounddown(avail_space, BTRFS_STRIPE_LEN);
1621
1622 /*
1623 * Ensure we have at least min_stripe_size on top of the
1624 * reserved space on the device.
1625 */
1626 if (avail_space <= BTRFS_DEVICE_RANGE_RESERVED + min_stripe_size)
1627 continue;
1628
1629 avail_space -= BTRFS_DEVICE_RANGE_RESERVED;
1630
1631 devices_info[i].dev = device;
1632 devices_info[i].max_avail = avail_space;
1633
1634 i++;
1635 }
1636 rcu_read_unlock();
1637
1638 nr_devices = i;
1639
1640 btrfs_descending_sort_devices(devices_info, nr_devices);
1641
1642 i = nr_devices - 1;
1643 avail_space = 0;
1644 while (nr_devices >= rattr->devs_min) {
1645 num_stripes = min(num_stripes, nr_devices);
1646
1647 if (devices_info[i].max_avail >= min_stripe_size) {
1648 int j;
1649 u64 alloc_size;
1650
1651 avail_space += devices_info[i].max_avail * num_stripes;
1652 alloc_size = devices_info[i].max_avail;
1653 for (j = i + 1 - num_stripes; j <= i; j++)
1654 devices_info[j].max_avail -= alloc_size;
1655 }
1656 i--;
1657 nr_devices--;
1658 }
1659
1660 kfree(devices_info);
1661 *free_bytes = avail_space;
1662 return 0;
1663}
1664
1665/*
1666 * Calculate numbers for 'df', pessimistic in case of mixed raid profiles.
1667 *
1668 * If there's a redundant raid level at DATA block groups, use the respective
1669 * multiplier to scale the sizes.
1670 *
1671 * Unused device space usage is based on simulating the chunk allocator
1672 * algorithm that respects the device sizes and order of allocations. This is
1673 * a close approximation of the actual use but there are other factors that may
1674 * change the result (like a new metadata chunk).
1675 *
1676 * If metadata is exhausted, f_bavail will be 0.
1677 */
1678static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
1679{
1680 struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
1681 struct btrfs_super_block *disk_super = fs_info->super_copy;
1682 struct btrfs_space_info *found;
1683 u64 total_used = 0;
1684 u64 total_free_data = 0;
1685 u64 total_free_meta = 0;
1686 u32 bits = fs_info->sectorsize_bits;
1687 __be32 *fsid = (__be32 *)fs_info->fs_devices->fsid;
1688 unsigned factor = 1;
1689 struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
1690 int ret;
1691 u64 thresh = 0;
1692 int mixed = 0;
1693
1694 list_for_each_entry(found, &fs_info->space_info, list) {
1695 if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
1696 int i;
1697
1698 total_free_data += found->disk_total - found->disk_used;
1699 total_free_data -=
1700 btrfs_account_ro_block_groups_free_space(found);
1701
1702 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
1703 if (!list_empty(&found->block_groups[i]))
1704 factor = btrfs_bg_type_to_factor(
1705 btrfs_raid_array[i].bg_flag);
1706 }
1707 }
1708
1709 /*
1710 * Metadata in mixed block group profiles are accounted in data
1711 */
1712 if (!mixed && found->flags & BTRFS_BLOCK_GROUP_METADATA) {
1713 if (found->flags & BTRFS_BLOCK_GROUP_DATA)
1714 mixed = 1;
1715 else
1716 total_free_meta += found->disk_total -
1717 found->disk_used;
1718 }
1719
1720 total_used += found->disk_used;
1721 }
1722
1723 buf->f_blocks = div_u64(btrfs_super_total_bytes(disk_super), factor);
1724 buf->f_blocks >>= bits;
1725 buf->f_bfree = buf->f_blocks - (div_u64(total_used, factor) >> bits);
1726
1727 /* Account global block reserve as used, it's in logical size already */
1728 spin_lock(&block_rsv->lock);
1729 /* Mixed block groups accounting is not byte-accurate, avoid overflow */
1730 if (buf->f_bfree >= block_rsv->size >> bits)
1731 buf->f_bfree -= block_rsv->size >> bits;
1732 else
1733 buf->f_bfree = 0;
1734 spin_unlock(&block_rsv->lock);
1735
1736 buf->f_bavail = div_u64(total_free_data, factor);
1737 ret = btrfs_calc_avail_data_space(fs_info, &total_free_data);
1738 if (ret)
1739 return ret;
1740 buf->f_bavail += div_u64(total_free_data, factor);
1741 buf->f_bavail = buf->f_bavail >> bits;
1742
1743 /*
1744 * We calculate the remaining metadata space minus global reserve. If
1745 * this is (supposedly) smaller than zero, there's no space. But this
1746 * does not hold in practice, the exhausted state happens where's still
1747 * some positive delta. So we apply some guesswork and compare the
1748 * delta to a 4M threshold. (Practically observed delta was ~2M.)
1749 *
1750 * We probably cannot calculate the exact threshold value because this
1751 * depends on the internal reservations requested by various
1752 * operations, so some operations that consume a few metadata will
1753 * succeed even if the Avail is zero. But this is better than the other
1754 * way around.
1755 */
1756 thresh = SZ_4M;
1757
1758 /*
1759 * We only want to claim there's no available space if we can no longer
1760 * allocate chunks for our metadata profile and our global reserve will
1761 * not fit in the free metadata space. If we aren't ->full then we
1762 * still can allocate chunks and thus are fine using the currently
1763 * calculated f_bavail.
1764 */
1765 if (!mixed && block_rsv->space_info->full &&
1766 (total_free_meta < thresh || total_free_meta - thresh < block_rsv->size))
1767 buf->f_bavail = 0;
1768
1769 buf->f_type = BTRFS_SUPER_MAGIC;
1770 buf->f_bsize = dentry->d_sb->s_blocksize;
1771 buf->f_namelen = BTRFS_NAME_LEN;
1772
1773 /* We treat it as constant endianness (it doesn't matter _which_)
1774 because we want the fsid to come out the same whether mounted
1775 on a big-endian or little-endian host */
1776 buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
1777 buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
1778 /* Mask in the root object ID too, to disambiguate subvols */
1779 buf->f_fsid.val[0] ^=
1780 BTRFS_I(d_inode(dentry))->root->root_key.objectid >> 32;
1781 buf->f_fsid.val[1] ^=
1782 BTRFS_I(d_inode(dentry))->root->root_key.objectid;
1783
1784 return 0;
1785}
1786
1787static int btrfs_fc_test_super(struct super_block *sb, struct fs_context *fc)
1788{
1789 struct btrfs_fs_info *p = fc->s_fs_info;
1790 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1791
1792 return fs_info->fs_devices == p->fs_devices;
1793}
1794
1795static int btrfs_get_tree_super(struct fs_context *fc)
1796{
1797 struct btrfs_fs_info *fs_info = fc->s_fs_info;
1798 struct btrfs_fs_context *ctx = fc->fs_private;
1799 struct btrfs_fs_devices *fs_devices = NULL;
1800 struct block_device *bdev;
1801 struct btrfs_device *device;
1802 struct super_block *sb;
1803 blk_mode_t mode = btrfs_open_mode(fc);
1804 int ret;
1805
1806 btrfs_ctx_to_info(fs_info, ctx);
1807 mutex_lock(&uuid_mutex);
1808
1809 /*
1810 * With 'true' passed to btrfs_scan_one_device() (mount time) we expect
1811 * either a valid device or an error.
1812 */
1813 device = btrfs_scan_one_device(fc->source, mode, true);
1814 ASSERT(device != NULL);
1815 if (IS_ERR(device)) {
1816 mutex_unlock(&uuid_mutex);
1817 return PTR_ERR(device);
1818 }
1819
1820 fs_devices = device->fs_devices;
1821 fs_info->fs_devices = fs_devices;
1822
1823 ret = btrfs_open_devices(fs_devices, mode, &btrfs_fs_type);
1824 mutex_unlock(&uuid_mutex);
1825 if (ret)
1826 return ret;
1827
1828 if (!(fc->sb_flags & SB_RDONLY) && fs_devices->rw_devices == 0) {
1829 ret = -EACCES;
1830 goto error;
1831 }
1832
1833 bdev = fs_devices->latest_dev->bdev;
1834
1835 /*
1836 * From now on the error handling is not straightforward.
1837 *
1838 * If successful, this will transfer the fs_info into the super block,
1839 * and fc->s_fs_info will be NULL. However if there's an existing
1840 * super, we'll still have fc->s_fs_info populated. If we error
1841 * completely out it'll be cleaned up when we drop the fs_context,
1842 * otherwise it's tied to the lifetime of the super_block.
1843 */
1844 sb = sget_fc(fc, btrfs_fc_test_super, set_anon_super_fc);
1845 if (IS_ERR(sb)) {
1846 ret = PTR_ERR(sb);
1847 goto error;
1848 }
1849
1850 set_device_specific_options(fs_info);
1851
1852 if (sb->s_root) {
1853 btrfs_close_devices(fs_devices);
1854 if ((fc->sb_flags ^ sb->s_flags) & SB_RDONLY)
1855 ret = -EBUSY;
1856 } else {
1857 snprintf(sb->s_id, sizeof(sb->s_id), "%pg", bdev);
1858 shrinker_debugfs_rename(sb->s_shrink, "sb-btrfs:%s", sb->s_id);
1859 btrfs_sb(sb)->bdev_holder = &btrfs_fs_type;
1860 ret = btrfs_fill_super(sb, fs_devices, NULL);
1861 }
1862
1863 if (ret) {
1864 deactivate_locked_super(sb);
1865 return ret;
1866 }
1867
1868 btrfs_clear_oneshot_options(fs_info);
1869
1870 fc->root = dget(sb->s_root);
1871 return 0;
1872
1873error:
1874 btrfs_close_devices(fs_devices);
1875 return ret;
1876}
1877
1878/*
1879 * Ever since commit 0723a0473fb4 ("btrfs: allow mounting btrfs subvolumes
1880 * with different ro/rw options") the following works:
1881 *
1882 * (i) mount /dev/sda3 -o subvol=foo,ro /mnt/foo
1883 * (ii) mount /dev/sda3 -o subvol=bar,rw /mnt/bar
1884 *
1885 * which looks nice and innocent but is actually pretty intricate and deserves
1886 * a long comment.
1887 *
1888 * On another filesystem a subvolume mount is close to something like:
1889 *
1890 * (iii) # create rw superblock + initial mount
1891 * mount -t xfs /dev/sdb /opt/
1892 *
1893 * # create ro bind mount
1894 * mount --bind -o ro /opt/foo /mnt/foo
1895 *
1896 * # unmount initial mount
1897 * umount /opt
1898 *
1899 * Of course, there's some special subvolume sauce and there's the fact that the
1900 * sb->s_root dentry is really swapped after mount_subtree(). But conceptually
1901 * it's very close and will help us understand the issue.
1902 *
1903 * The old mount API didn't cleanly distinguish between a mount being made ro
1904 * and a superblock being made ro. The only way to change the ro state of
1905 * either object was by passing ms_rdonly. If a new mount was created via
1906 * mount(2) such as:
1907 *
1908 * mount("/dev/sdb", "/mnt", "xfs", ms_rdonly, null);
1909 *
1910 * the MS_RDONLY flag being specified had two effects:
1911 *
1912 * (1) MNT_READONLY was raised -> the resulting mount got
1913 * @mnt->mnt_flags |= MNT_READONLY raised.
1914 *
1915 * (2) MS_RDONLY was passed to the filesystem's mount method and the filesystems
1916 * made the superblock ro. Note, how SB_RDONLY has the same value as
1917 * ms_rdonly and is raised whenever MS_RDONLY is passed through mount(2).
1918 *
1919 * Creating a subtree mount via (iii) ends up leaving a rw superblock with a
1920 * subtree mounted ro.
1921 *
1922 * But consider the effect on the old mount API on btrfs subvolume mounting
1923 * which combines the distinct step in (iii) into a single step.
1924 *
1925 * By issuing (i) both the mount and the superblock are turned ro. Now when (ii)
1926 * is issued the superblock is ro and thus even if the mount created for (ii) is
1927 * rw it wouldn't help. Hence, btrfs needed to transition the superblock from ro
1928 * to rw for (ii) which it did using an internal remount call.
1929 *
1930 * IOW, subvolume mounting was inherently complicated due to the ambiguity of
1931 * MS_RDONLY in mount(2). Note, this ambiguity has mount(8) always translate
1932 * "ro" to MS_RDONLY. IOW, in both (i) and (ii) "ro" becomes MS_RDONLY when
1933 * passed by mount(8) to mount(2).
1934 *
1935 * Enter the new mount API. The new mount API disambiguates making a mount ro
1936 * and making a superblock ro.
1937 *
1938 * (3) To turn a mount ro the MOUNT_ATTR_ONLY flag can be used with either
1939 * fsmount() or mount_setattr() this is a pure VFS level change for a
1940 * specific mount or mount tree that is never seen by the filesystem itself.
1941 *
1942 * (4) To turn a superblock ro the "ro" flag must be used with
1943 * fsconfig(FSCONFIG_SET_FLAG, "ro"). This option is seen by the filesystem
1944 * in fc->sb_flags.
1945 *
1946 * This disambiguation has rather positive consequences. Mounting a subvolume
1947 * ro will not also turn the superblock ro. Only the mount for the subvolume
1948 * will become ro.
1949 *
1950 * So, if the superblock creation request comes from the new mount API the
1951 * caller must have explicitly done:
1952 *
1953 * fsconfig(FSCONFIG_SET_FLAG, "ro")
1954 * fsmount/mount_setattr(MOUNT_ATTR_RDONLY)
1955 *
1956 * IOW, at some point the caller must have explicitly turned the whole
1957 * superblock ro and we shouldn't just undo it like we did for the old mount
1958 * API. In any case, it lets us avoid the hack in the new mount API.
1959 *
1960 * Consequently, the remounting hack must only be used for requests originating
1961 * from the old mount API and should be marked for full deprecation so it can be
1962 * turned off in a couple of years.
1963 *
1964 * The new mount API has no reason to support this hack.
1965 */
1966static struct vfsmount *btrfs_reconfigure_for_mount(struct fs_context *fc)
1967{
1968 struct vfsmount *mnt;
1969 int ret;
1970 const bool ro2rw = !(fc->sb_flags & SB_RDONLY);
1971
1972 /*
1973 * We got an EBUSY because our SB_RDONLY flag didn't match the existing
1974 * super block, so invert our setting here and retry the mount so we
1975 * can get our vfsmount.
1976 */
1977 if (ro2rw)
1978 fc->sb_flags |= SB_RDONLY;
1979 else
1980 fc->sb_flags &= ~SB_RDONLY;
1981
1982 mnt = fc_mount(fc);
1983 if (IS_ERR(mnt))
1984 return mnt;
1985
1986 if (!fc->oldapi || !ro2rw)
1987 return mnt;
1988
1989 /* We need to convert to rw, call reconfigure. */
1990 fc->sb_flags &= ~SB_RDONLY;
1991 down_write(&mnt->mnt_sb->s_umount);
1992 ret = btrfs_reconfigure(fc);
1993 up_write(&mnt->mnt_sb->s_umount);
1994 if (ret) {
1995 mntput(mnt);
1996 return ERR_PTR(ret);
1997 }
1998 return mnt;
1999}
2000
2001static int btrfs_get_tree_subvol(struct fs_context *fc)
2002{
2003 struct btrfs_fs_info *fs_info = NULL;
2004 struct btrfs_fs_context *ctx = fc->fs_private;
2005 struct fs_context *dup_fc;
2006 struct dentry *dentry;
2007 struct vfsmount *mnt;
2008
2009 /*
2010 * Setup a dummy root and fs_info for test/set super. This is because
2011 * we don't actually fill this stuff out until open_ctree, but we need
2012 * then open_ctree will properly initialize the file system specific
2013 * settings later. btrfs_init_fs_info initializes the static elements
2014 * of the fs_info (locks and such) to make cleanup easier if we find a
2015 * superblock with our given fs_devices later on at sget() time.
2016 */
2017 fs_info = kvzalloc(sizeof(struct btrfs_fs_info), GFP_KERNEL);
2018 if (!fs_info)
2019 return -ENOMEM;
2020
2021 fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
2022 fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
2023 if (!fs_info->super_copy || !fs_info->super_for_commit) {
2024 btrfs_free_fs_info(fs_info);
2025 return -ENOMEM;
2026 }
2027 btrfs_init_fs_info(fs_info);
2028
2029 dup_fc = vfs_dup_fs_context(fc);
2030 if (IS_ERR(dup_fc)) {
2031 btrfs_free_fs_info(fs_info);
2032 return PTR_ERR(dup_fc);
2033 }
2034
2035 /*
2036 * When we do the sget_fc this gets transferred to the sb, so we only
2037 * need to set it on the dup_fc as this is what creates the super block.
2038 */
2039 dup_fc->s_fs_info = fs_info;
2040
2041 /*
2042 * We'll do the security settings in our btrfs_get_tree_super() mount
2043 * loop, they were duplicated into dup_fc, we can drop the originals
2044 * here.
2045 */
2046 security_free_mnt_opts(&fc->security);
2047 fc->security = NULL;
2048
2049 mnt = fc_mount(dup_fc);
2050 if (PTR_ERR_OR_ZERO(mnt) == -EBUSY)
2051 mnt = btrfs_reconfigure_for_mount(dup_fc);
2052 put_fs_context(dup_fc);
2053 if (IS_ERR(mnt))
2054 return PTR_ERR(mnt);
2055
2056 /*
2057 * This free's ->subvol_name, because if it isn't set we have to
2058 * allocate a buffer to hold the subvol_name, so we just drop our
2059 * reference to it here.
2060 */
2061 dentry = mount_subvol(ctx->subvol_name, ctx->subvol_objectid, mnt);
2062 ctx->subvol_name = NULL;
2063 if (IS_ERR(dentry))
2064 return PTR_ERR(dentry);
2065
2066 fc->root = dentry;
2067 return 0;
2068}
2069
2070static int btrfs_get_tree(struct fs_context *fc)
2071{
2072 /*
2073 * Since we use mount_subtree to mount the default/specified subvol, we
2074 * have to do mounts in two steps.
2075 *
2076 * First pass through we call btrfs_get_tree_subvol(), this is just a
2077 * wrapper around fc_mount() to call back into here again, and this time
2078 * we'll call btrfs_get_tree_super(). This will do the open_ctree() and
2079 * everything to open the devices and file system. Then we return back
2080 * with a fully constructed vfsmount in btrfs_get_tree_subvol(), and
2081 * from there we can do our mount_subvol() call, which will lookup
2082 * whichever subvol we're mounting and setup this fc with the
2083 * appropriate dentry for the subvol.
2084 */
2085 if (fc->s_fs_info)
2086 return btrfs_get_tree_super(fc);
2087 return btrfs_get_tree_subvol(fc);
2088}
2089
2090static void btrfs_kill_super(struct super_block *sb)
2091{
2092 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2093 kill_anon_super(sb);
2094 btrfs_free_fs_info(fs_info);
2095}
2096
2097static void btrfs_free_fs_context(struct fs_context *fc)
2098{
2099 struct btrfs_fs_context *ctx = fc->fs_private;
2100 struct btrfs_fs_info *fs_info = fc->s_fs_info;
2101
2102 if (fs_info)
2103 btrfs_free_fs_info(fs_info);
2104
2105 if (ctx && refcount_dec_and_test(&ctx->refs)) {
2106 kfree(ctx->subvol_name);
2107 kfree(ctx);
2108 }
2109}
2110
2111static int btrfs_dup_fs_context(struct fs_context *fc, struct fs_context *src_fc)
2112{
2113 struct btrfs_fs_context *ctx = src_fc->fs_private;
2114
2115 /*
2116 * Give a ref to our ctx to this dup, as we want to keep it around for
2117 * our original fc so we can have the subvolume name or objectid.
2118 *
2119 * We unset ->source in the original fc because the dup needs it for
2120 * mounting, and then once we free the dup it'll free ->source, so we
2121 * need to make sure we're only pointing to it in one fc.
2122 */
2123 refcount_inc(&ctx->refs);
2124 fc->fs_private = ctx;
2125 fc->source = src_fc->source;
2126 src_fc->source = NULL;
2127 return 0;
2128}
2129
2130static const struct fs_context_operations btrfs_fs_context_ops = {
2131 .parse_param = btrfs_parse_param,
2132 .reconfigure = btrfs_reconfigure,
2133 .get_tree = btrfs_get_tree,
2134 .dup = btrfs_dup_fs_context,
2135 .free = btrfs_free_fs_context,
2136};
2137
2138static int btrfs_init_fs_context(struct fs_context *fc)
2139{
2140 struct btrfs_fs_context *ctx;
2141
2142 ctx = kzalloc(sizeof(struct btrfs_fs_context), GFP_KERNEL);
2143 if (!ctx)
2144 return -ENOMEM;
2145
2146 refcount_set(&ctx->refs, 1);
2147 fc->fs_private = ctx;
2148 fc->ops = &btrfs_fs_context_ops;
2149
2150 if (fc->purpose == FS_CONTEXT_FOR_RECONFIGURE) {
2151 btrfs_info_to_ctx(btrfs_sb(fc->root->d_sb), ctx);
2152 } else {
2153 ctx->thread_pool_size =
2154 min_t(unsigned long, num_online_cpus() + 2, 8);
2155 ctx->max_inline = BTRFS_DEFAULT_MAX_INLINE;
2156 ctx->commit_interval = BTRFS_DEFAULT_COMMIT_INTERVAL;
2157 }
2158
2159#ifdef CONFIG_BTRFS_FS_POSIX_ACL
2160 fc->sb_flags |= SB_POSIXACL;
2161#endif
2162 fc->sb_flags |= SB_I_VERSION;
2163
2164 return 0;
2165}
2166
2167static struct file_system_type btrfs_fs_type = {
2168 .owner = THIS_MODULE,
2169 .name = "btrfs",
2170 .init_fs_context = btrfs_init_fs_context,
2171 .parameters = btrfs_fs_parameters,
2172 .kill_sb = btrfs_kill_super,
2173 .fs_flags = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA | FS_ALLOW_IDMAP,
2174 };
2175
2176MODULE_ALIAS_FS("btrfs");
2177
2178static int btrfs_control_open(struct inode *inode, struct file *file)
2179{
2180 /*
2181 * The control file's private_data is used to hold the
2182 * transaction when it is started and is used to keep
2183 * track of whether a transaction is already in progress.
2184 */
2185 file->private_data = NULL;
2186 return 0;
2187}
2188
2189/*
2190 * Used by /dev/btrfs-control for devices ioctls.
2191 */
2192static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
2193 unsigned long arg)
2194{
2195 struct btrfs_ioctl_vol_args *vol;
2196 struct btrfs_device *device = NULL;
2197 dev_t devt = 0;
2198 int ret = -ENOTTY;
2199
2200 if (!capable(CAP_SYS_ADMIN))
2201 return -EPERM;
2202
2203 vol = memdup_user((void __user *)arg, sizeof(*vol));
2204 if (IS_ERR(vol))
2205 return PTR_ERR(vol);
2206 vol->name[BTRFS_PATH_NAME_MAX] = '\0';
2207
2208 switch (cmd) {
2209 case BTRFS_IOC_SCAN_DEV:
2210 mutex_lock(&uuid_mutex);
2211 /*
2212 * Scanning outside of mount can return NULL which would turn
2213 * into 0 error code.
2214 */
2215 device = btrfs_scan_one_device(vol->name, BLK_OPEN_READ, false);
2216 ret = PTR_ERR_OR_ZERO(device);
2217 mutex_unlock(&uuid_mutex);
2218 break;
2219 case BTRFS_IOC_FORGET_DEV:
2220 if (vol->name[0] != 0) {
2221 ret = lookup_bdev(vol->name, &devt);
2222 if (ret)
2223 break;
2224 }
2225 ret = btrfs_forget_devices(devt);
2226 break;
2227 case BTRFS_IOC_DEVICES_READY:
2228 mutex_lock(&uuid_mutex);
2229 /*
2230 * Scanning outside of mount can return NULL which would turn
2231 * into 0 error code.
2232 */
2233 device = btrfs_scan_one_device(vol->name, BLK_OPEN_READ, false);
2234 if (IS_ERR_OR_NULL(device)) {
2235 mutex_unlock(&uuid_mutex);
2236 ret = PTR_ERR(device);
2237 break;
2238 }
2239 ret = !(device->fs_devices->num_devices ==
2240 device->fs_devices->total_devices);
2241 mutex_unlock(&uuid_mutex);
2242 break;
2243 case BTRFS_IOC_GET_SUPPORTED_FEATURES:
2244 ret = btrfs_ioctl_get_supported_features((void __user*)arg);
2245 break;
2246 }
2247
2248 kfree(vol);
2249 return ret;
2250}
2251
2252static int btrfs_freeze(struct super_block *sb)
2253{
2254 struct btrfs_trans_handle *trans;
2255 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2256 struct btrfs_root *root = fs_info->tree_root;
2257
2258 set_bit(BTRFS_FS_FROZEN, &fs_info->flags);
2259 /*
2260 * We don't need a barrier here, we'll wait for any transaction that
2261 * could be in progress on other threads (and do delayed iputs that
2262 * we want to avoid on a frozen filesystem), or do the commit
2263 * ourselves.
2264 */
2265 trans = btrfs_attach_transaction_barrier(root);
2266 if (IS_ERR(trans)) {
2267 /* no transaction, don't bother */
2268 if (PTR_ERR(trans) == -ENOENT)
2269 return 0;
2270 return PTR_ERR(trans);
2271 }
2272 return btrfs_commit_transaction(trans);
2273}
2274
2275static int check_dev_super(struct btrfs_device *dev)
2276{
2277 struct btrfs_fs_info *fs_info = dev->fs_info;
2278 struct btrfs_super_block *sb;
2279 u64 last_trans;
2280 u16 csum_type;
2281 int ret = 0;
2282
2283 /* This should be called with fs still frozen. */
2284 ASSERT(test_bit(BTRFS_FS_FROZEN, &fs_info->flags));
2285
2286 /* Missing dev, no need to check. */
2287 if (!dev->bdev)
2288 return 0;
2289
2290 /* Only need to check the primary super block. */
2291 sb = btrfs_read_dev_one_super(dev->bdev, 0, true);
2292 if (IS_ERR(sb))
2293 return PTR_ERR(sb);
2294
2295 /* Verify the checksum. */
2296 csum_type = btrfs_super_csum_type(sb);
2297 if (csum_type != btrfs_super_csum_type(fs_info->super_copy)) {
2298 btrfs_err(fs_info, "csum type changed, has %u expect %u",
2299 csum_type, btrfs_super_csum_type(fs_info->super_copy));
2300 ret = -EUCLEAN;
2301 goto out;
2302 }
2303
2304 if (btrfs_check_super_csum(fs_info, sb)) {
2305 btrfs_err(fs_info, "csum for on-disk super block no longer matches");
2306 ret = -EUCLEAN;
2307 goto out;
2308 }
2309
2310 /* Btrfs_validate_super() includes fsid check against super->fsid. */
2311 ret = btrfs_validate_super(fs_info, sb, 0);
2312 if (ret < 0)
2313 goto out;
2314
2315 last_trans = btrfs_get_last_trans_committed(fs_info);
2316 if (btrfs_super_generation(sb) != last_trans) {
2317 btrfs_err(fs_info, "transid mismatch, has %llu expect %llu",
2318 btrfs_super_generation(sb), last_trans);
2319 ret = -EUCLEAN;
2320 goto out;
2321 }
2322out:
2323 btrfs_release_disk_super(sb);
2324 return ret;
2325}
2326
2327static int btrfs_unfreeze(struct super_block *sb)
2328{
2329 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2330 struct btrfs_device *device;
2331 int ret = 0;
2332
2333 /*
2334 * Make sure the fs is not changed by accident (like hibernation then
2335 * modified by other OS).
2336 * If we found anything wrong, we mark the fs error immediately.
2337 *
2338 * And since the fs is frozen, no one can modify the fs yet, thus
2339 * we don't need to hold device_list_mutex.
2340 */
2341 list_for_each_entry(device, &fs_info->fs_devices->devices, dev_list) {
2342 ret = check_dev_super(device);
2343 if (ret < 0) {
2344 btrfs_handle_fs_error(fs_info, ret,
2345 "super block on devid %llu got modified unexpectedly",
2346 device->devid);
2347 break;
2348 }
2349 }
2350 clear_bit(BTRFS_FS_FROZEN, &fs_info->flags);
2351
2352 /*
2353 * We still return 0, to allow VFS layer to unfreeze the fs even the
2354 * above checks failed. Since the fs is either fine or read-only, we're
2355 * safe to continue, without causing further damage.
2356 */
2357 return 0;
2358}
2359
2360static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
2361{
2362 struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
2363
2364 /*
2365 * There should be always a valid pointer in latest_dev, it may be stale
2366 * for a short moment in case it's being deleted but still valid until
2367 * the end of RCU grace period.
2368 */
2369 rcu_read_lock();
2370 seq_escape(m, btrfs_dev_name(fs_info->fs_devices->latest_dev), " \t\n\\");
2371 rcu_read_unlock();
2372
2373 return 0;
2374}
2375
2376static const struct super_operations btrfs_super_ops = {
2377 .drop_inode = btrfs_drop_inode,
2378 .evict_inode = btrfs_evict_inode,
2379 .put_super = btrfs_put_super,
2380 .sync_fs = btrfs_sync_fs,
2381 .show_options = btrfs_show_options,
2382 .show_devname = btrfs_show_devname,
2383 .alloc_inode = btrfs_alloc_inode,
2384 .destroy_inode = btrfs_destroy_inode,
2385 .free_inode = btrfs_free_inode,
2386 .statfs = btrfs_statfs,
2387 .freeze_fs = btrfs_freeze,
2388 .unfreeze_fs = btrfs_unfreeze,
2389};
2390
2391static const struct file_operations btrfs_ctl_fops = {
2392 .open = btrfs_control_open,
2393 .unlocked_ioctl = btrfs_control_ioctl,
2394 .compat_ioctl = compat_ptr_ioctl,
2395 .owner = THIS_MODULE,
2396 .llseek = noop_llseek,
2397};
2398
2399static struct miscdevice btrfs_misc = {
2400 .minor = BTRFS_MINOR,
2401 .name = "btrfs-control",
2402 .fops = &btrfs_ctl_fops
2403};
2404
2405MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
2406MODULE_ALIAS("devname:btrfs-control");
2407
2408static int __init btrfs_interface_init(void)
2409{
2410 return misc_register(&btrfs_misc);
2411}
2412
2413static __cold void btrfs_interface_exit(void)
2414{
2415 misc_deregister(&btrfs_misc);
2416}
2417
2418static int __init btrfs_print_mod_info(void)
2419{
2420 static const char options[] = ""
2421#ifdef CONFIG_BTRFS_DEBUG
2422 ", debug=on"
2423#endif
2424#ifdef CONFIG_BTRFS_ASSERT
2425 ", assert=on"
2426#endif
2427#ifdef CONFIG_BTRFS_FS_REF_VERIFY
2428 ", ref-verify=on"
2429#endif
2430#ifdef CONFIG_BLK_DEV_ZONED
2431 ", zoned=yes"
2432#else
2433 ", zoned=no"
2434#endif
2435#ifdef CONFIG_FS_VERITY
2436 ", fsverity=yes"
2437#else
2438 ", fsverity=no"
2439#endif
2440 ;
2441 pr_info("Btrfs loaded%s\n", options);
2442 return 0;
2443}
2444
2445static int register_btrfs(void)
2446{
2447 return register_filesystem(&btrfs_fs_type);
2448}
2449
2450static void unregister_btrfs(void)
2451{
2452 unregister_filesystem(&btrfs_fs_type);
2453}
2454
2455/* Helper structure for long init/exit functions. */
2456struct init_sequence {
2457 int (*init_func)(void);
2458 /* Can be NULL if the init_func doesn't need cleanup. */
2459 void (*exit_func)(void);
2460};
2461
2462static const struct init_sequence mod_init_seq[] = {
2463 {
2464 .init_func = btrfs_props_init,
2465 .exit_func = NULL,
2466 }, {
2467 .init_func = btrfs_init_sysfs,
2468 .exit_func = btrfs_exit_sysfs,
2469 }, {
2470 .init_func = btrfs_init_compress,
2471 .exit_func = btrfs_exit_compress,
2472 }, {
2473 .init_func = btrfs_init_cachep,
2474 .exit_func = btrfs_destroy_cachep,
2475 }, {
2476 .init_func = btrfs_transaction_init,
2477 .exit_func = btrfs_transaction_exit,
2478 }, {
2479 .init_func = btrfs_ctree_init,
2480 .exit_func = btrfs_ctree_exit,
2481 }, {
2482 .init_func = btrfs_free_space_init,
2483 .exit_func = btrfs_free_space_exit,
2484 }, {
2485 .init_func = extent_state_init_cachep,
2486 .exit_func = extent_state_free_cachep,
2487 }, {
2488 .init_func = extent_buffer_init_cachep,
2489 .exit_func = extent_buffer_free_cachep,
2490 }, {
2491 .init_func = btrfs_bioset_init,
2492 .exit_func = btrfs_bioset_exit,
2493 }, {
2494 .init_func = extent_map_init,
2495 .exit_func = extent_map_exit,
2496 }, {
2497 .init_func = ordered_data_init,
2498 .exit_func = ordered_data_exit,
2499 }, {
2500 .init_func = btrfs_delayed_inode_init,
2501 .exit_func = btrfs_delayed_inode_exit,
2502 }, {
2503 .init_func = btrfs_auto_defrag_init,
2504 .exit_func = btrfs_auto_defrag_exit,
2505 }, {
2506 .init_func = btrfs_delayed_ref_init,
2507 .exit_func = btrfs_delayed_ref_exit,
2508 }, {
2509 .init_func = btrfs_prelim_ref_init,
2510 .exit_func = btrfs_prelim_ref_exit,
2511 }, {
2512 .init_func = btrfs_interface_init,
2513 .exit_func = btrfs_interface_exit,
2514 }, {
2515 .init_func = btrfs_print_mod_info,
2516 .exit_func = NULL,
2517 }, {
2518 .init_func = btrfs_run_sanity_tests,
2519 .exit_func = NULL,
2520 }, {
2521 .init_func = register_btrfs,
2522 .exit_func = unregister_btrfs,
2523 }
2524};
2525
2526static bool mod_init_result[ARRAY_SIZE(mod_init_seq)];
2527
2528static __always_inline void btrfs_exit_btrfs_fs(void)
2529{
2530 int i;
2531
2532 for (i = ARRAY_SIZE(mod_init_seq) - 1; i >= 0; i--) {
2533 if (!mod_init_result[i])
2534 continue;
2535 if (mod_init_seq[i].exit_func)
2536 mod_init_seq[i].exit_func();
2537 mod_init_result[i] = false;
2538 }
2539}
2540
2541static void __exit exit_btrfs_fs(void)
2542{
2543 btrfs_exit_btrfs_fs();
2544 btrfs_cleanup_fs_uuids();
2545}
2546
2547static int __init init_btrfs_fs(void)
2548{
2549 int ret;
2550 int i;
2551
2552 for (i = 0; i < ARRAY_SIZE(mod_init_seq); i++) {
2553 ASSERT(!mod_init_result[i]);
2554 ret = mod_init_seq[i].init_func();
2555 if (ret < 0) {
2556 btrfs_exit_btrfs_fs();
2557 return ret;
2558 }
2559 mod_init_result[i] = true;
2560 }
2561 return 0;
2562}
2563
2564late_initcall(init_btrfs_fs);
2565module_exit(exit_btrfs_fs)
2566
2567MODULE_LICENSE("GPL");
2568MODULE_SOFTDEP("pre: crc32c");
2569MODULE_SOFTDEP("pre: xxhash64");
2570MODULE_SOFTDEP("pre: sha256");
2571MODULE_SOFTDEP("pre: blake2b-256");
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2007 Oracle. All rights reserved.
4 */
5
6#include <linux/blkdev.h>
7#include <linux/module.h>
8#include <linux/buffer_head.h>
9#include <linux/fs.h>
10#include <linux/pagemap.h>
11#include <linux/highmem.h>
12#include <linux/time.h>
13#include <linux/init.h>
14#include <linux/seq_file.h>
15#include <linux/string.h>
16#include <linux/backing-dev.h>
17#include <linux/mount.h>
18#include <linux/mpage.h>
19#include <linux/swap.h>
20#include <linux/writeback.h>
21#include <linux/statfs.h>
22#include <linux/compat.h>
23#include <linux/parser.h>
24#include <linux/ctype.h>
25#include <linux/namei.h>
26#include <linux/miscdevice.h>
27#include <linux/magic.h>
28#include <linux/slab.h>
29#include <linux/cleancache.h>
30#include <linux/ratelimit.h>
31#include <linux/crc32c.h>
32#include <linux/btrfs.h>
33#include "delayed-inode.h"
34#include "ctree.h"
35#include "disk-io.h"
36#include "transaction.h"
37#include "btrfs_inode.h"
38#include "print-tree.h"
39#include "props.h"
40#include "xattr.h"
41#include "volumes.h"
42#include "export.h"
43#include "compression.h"
44#include "rcu-string.h"
45#include "dev-replace.h"
46#include "free-space-cache.h"
47#include "backref.h"
48#include "tests/btrfs-tests.h"
49
50#include "qgroup.h"
51#define CREATE_TRACE_POINTS
52#include <trace/events/btrfs.h>
53
54static const struct super_operations btrfs_super_ops;
55
56/*
57 * Types for mounting the default subvolume and a subvolume explicitly
58 * requested by subvol=/path. That way the callchain is straightforward and we
59 * don't have to play tricks with the mount options and recursive calls to
60 * btrfs_mount.
61 *
62 * The new btrfs_root_fs_type also servers as a tag for the bdev_holder.
63 */
64static struct file_system_type btrfs_fs_type;
65static struct file_system_type btrfs_root_fs_type;
66
67static int btrfs_remount(struct super_block *sb, int *flags, char *data);
68
69const char *btrfs_decode_error(int errno)
70{
71 char *errstr = "unknown";
72
73 switch (errno) {
74 case -EIO:
75 errstr = "IO failure";
76 break;
77 case -ENOMEM:
78 errstr = "Out of memory";
79 break;
80 case -EROFS:
81 errstr = "Readonly filesystem";
82 break;
83 case -EEXIST:
84 errstr = "Object already exists";
85 break;
86 case -ENOSPC:
87 errstr = "No space left";
88 break;
89 case -ENOENT:
90 errstr = "No such entry";
91 break;
92 }
93
94 return errstr;
95}
96
97/*
98 * __btrfs_handle_fs_error decodes expected errors from the caller and
99 * invokes the approciate error response.
100 */
101__cold
102void __btrfs_handle_fs_error(struct btrfs_fs_info *fs_info, const char *function,
103 unsigned int line, int errno, const char *fmt, ...)
104{
105 struct super_block *sb = fs_info->sb;
106#ifdef CONFIG_PRINTK
107 const char *errstr;
108#endif
109
110 /*
111 * Special case: if the error is EROFS, and we're already
112 * under SB_RDONLY, then it is safe here.
113 */
114 if (errno == -EROFS && sb_rdonly(sb))
115 return;
116
117#ifdef CONFIG_PRINTK
118 errstr = btrfs_decode_error(errno);
119 if (fmt) {
120 struct va_format vaf;
121 va_list args;
122
123 va_start(args, fmt);
124 vaf.fmt = fmt;
125 vaf.va = &args;
126
127 pr_crit("BTRFS: error (device %s) in %s:%d: errno=%d %s (%pV)\n",
128 sb->s_id, function, line, errno, errstr, &vaf);
129 va_end(args);
130 } else {
131 pr_crit("BTRFS: error (device %s) in %s:%d: errno=%d %s\n",
132 sb->s_id, function, line, errno, errstr);
133 }
134#endif
135
136 /*
137 * Today we only save the error info to memory. Long term we'll
138 * also send it down to the disk
139 */
140 set_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state);
141
142 /* Don't go through full error handling during mount */
143 if (!(sb->s_flags & SB_BORN))
144 return;
145
146 if (sb_rdonly(sb))
147 return;
148
149 /* btrfs handle error by forcing the filesystem readonly */
150 sb->s_flags |= SB_RDONLY;
151 btrfs_info(fs_info, "forced readonly");
152 /*
153 * Note that a running device replace operation is not canceled here
154 * although there is no way to update the progress. It would add the
155 * risk of a deadlock, therefore the canceling is omitted. The only
156 * penalty is that some I/O remains active until the procedure
157 * completes. The next time when the filesystem is mounted writeable
158 * again, the device replace operation continues.
159 */
160}
161
162#ifdef CONFIG_PRINTK
163static const char * const logtypes[] = {
164 "emergency",
165 "alert",
166 "critical",
167 "error",
168 "warning",
169 "notice",
170 "info",
171 "debug",
172};
173
174
175/*
176 * Use one ratelimit state per log level so that a flood of less important
177 * messages doesn't cause more important ones to be dropped.
178 */
179static struct ratelimit_state printk_limits[] = {
180 RATELIMIT_STATE_INIT(printk_limits[0], DEFAULT_RATELIMIT_INTERVAL, 100),
181 RATELIMIT_STATE_INIT(printk_limits[1], DEFAULT_RATELIMIT_INTERVAL, 100),
182 RATELIMIT_STATE_INIT(printk_limits[2], DEFAULT_RATELIMIT_INTERVAL, 100),
183 RATELIMIT_STATE_INIT(printk_limits[3], DEFAULT_RATELIMIT_INTERVAL, 100),
184 RATELIMIT_STATE_INIT(printk_limits[4], DEFAULT_RATELIMIT_INTERVAL, 100),
185 RATELIMIT_STATE_INIT(printk_limits[5], DEFAULT_RATELIMIT_INTERVAL, 100),
186 RATELIMIT_STATE_INIT(printk_limits[6], DEFAULT_RATELIMIT_INTERVAL, 100),
187 RATELIMIT_STATE_INIT(printk_limits[7], DEFAULT_RATELIMIT_INTERVAL, 100),
188};
189
190void btrfs_printk(const struct btrfs_fs_info *fs_info, const char *fmt, ...)
191{
192 char lvl[PRINTK_MAX_SINGLE_HEADER_LEN + 1] = "\0";
193 struct va_format vaf;
194 va_list args;
195 int kern_level;
196 const char *type = logtypes[4];
197 struct ratelimit_state *ratelimit = &printk_limits[4];
198
199 va_start(args, fmt);
200
201 while ((kern_level = printk_get_level(fmt)) != 0) {
202 size_t size = printk_skip_level(fmt) - fmt;
203
204 if (kern_level >= '0' && kern_level <= '7') {
205 memcpy(lvl, fmt, size);
206 lvl[size] = '\0';
207 type = logtypes[kern_level - '0'];
208 ratelimit = &printk_limits[kern_level - '0'];
209 }
210 fmt += size;
211 }
212
213 vaf.fmt = fmt;
214 vaf.va = &args;
215
216 if (__ratelimit(ratelimit))
217 printk("%sBTRFS %s (device %s): %pV\n", lvl, type,
218 fs_info ? fs_info->sb->s_id : "<unknown>", &vaf);
219
220 va_end(args);
221}
222#endif
223
224/*
225 * We only mark the transaction aborted and then set the file system read-only.
226 * This will prevent new transactions from starting or trying to join this
227 * one.
228 *
229 * This means that error recovery at the call site is limited to freeing
230 * any local memory allocations and passing the error code up without
231 * further cleanup. The transaction should complete as it normally would
232 * in the call path but will return -EIO.
233 *
234 * We'll complete the cleanup in btrfs_end_transaction and
235 * btrfs_commit_transaction.
236 */
237__cold
238void __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
239 const char *function,
240 unsigned int line, int errno)
241{
242 struct btrfs_fs_info *fs_info = trans->fs_info;
243
244 trans->aborted = errno;
245 /* Nothing used. The other threads that have joined this
246 * transaction may be able to continue. */
247 if (!trans->dirty && list_empty(&trans->new_bgs)) {
248 const char *errstr;
249
250 errstr = btrfs_decode_error(errno);
251 btrfs_warn(fs_info,
252 "%s:%d: Aborting unused transaction(%s).",
253 function, line, errstr);
254 return;
255 }
256 WRITE_ONCE(trans->transaction->aborted, errno);
257 /* Wake up anybody who may be waiting on this transaction */
258 wake_up(&fs_info->transaction_wait);
259 wake_up(&fs_info->transaction_blocked_wait);
260 __btrfs_handle_fs_error(fs_info, function, line, errno, NULL);
261}
262/*
263 * __btrfs_panic decodes unexpected, fatal errors from the caller,
264 * issues an alert, and either panics or BUGs, depending on mount options.
265 */
266__cold
267void __btrfs_panic(struct btrfs_fs_info *fs_info, const char *function,
268 unsigned int line, int errno, const char *fmt, ...)
269{
270 char *s_id = "<unknown>";
271 const char *errstr;
272 struct va_format vaf = { .fmt = fmt };
273 va_list args;
274
275 if (fs_info)
276 s_id = fs_info->sb->s_id;
277
278 va_start(args, fmt);
279 vaf.va = &args;
280
281 errstr = btrfs_decode_error(errno);
282 if (fs_info && (btrfs_test_opt(fs_info, PANIC_ON_FATAL_ERROR)))
283 panic(KERN_CRIT "BTRFS panic (device %s) in %s:%d: %pV (errno=%d %s)\n",
284 s_id, function, line, &vaf, errno, errstr);
285
286 btrfs_crit(fs_info, "panic in %s:%d: %pV (errno=%d %s)",
287 function, line, &vaf, errno, errstr);
288 va_end(args);
289 /* Caller calls BUG() */
290}
291
292static void btrfs_put_super(struct super_block *sb)
293{
294 close_ctree(btrfs_sb(sb));
295}
296
297enum {
298 Opt_acl, Opt_noacl,
299 Opt_clear_cache,
300 Opt_commit_interval,
301 Opt_compress,
302 Opt_compress_force,
303 Opt_compress_force_type,
304 Opt_compress_type,
305 Opt_degraded,
306 Opt_device,
307 Opt_fatal_errors,
308 Opt_flushoncommit, Opt_noflushoncommit,
309 Opt_inode_cache, Opt_noinode_cache,
310 Opt_max_inline,
311 Opt_barrier, Opt_nobarrier,
312 Opt_datacow, Opt_nodatacow,
313 Opt_datasum, Opt_nodatasum,
314 Opt_defrag, Opt_nodefrag,
315 Opt_discard, Opt_nodiscard,
316 Opt_nologreplay,
317 Opt_norecovery,
318 Opt_ratio,
319 Opt_rescan_uuid_tree,
320 Opt_skip_balance,
321 Opt_space_cache, Opt_no_space_cache,
322 Opt_space_cache_version,
323 Opt_ssd, Opt_nossd,
324 Opt_ssd_spread, Opt_nossd_spread,
325 Opt_subvol,
326 Opt_subvolid,
327 Opt_thread_pool,
328 Opt_treelog, Opt_notreelog,
329 Opt_usebackuproot,
330 Opt_user_subvol_rm_allowed,
331
332 /* Deprecated options */
333 Opt_alloc_start,
334 Opt_recovery,
335 Opt_subvolrootid,
336
337 /* Debugging options */
338 Opt_check_integrity,
339 Opt_check_integrity_including_extent_data,
340 Opt_check_integrity_print_mask,
341 Opt_enospc_debug, Opt_noenospc_debug,
342#ifdef CONFIG_BTRFS_DEBUG
343 Opt_fragment_data, Opt_fragment_metadata, Opt_fragment_all,
344#endif
345#ifdef CONFIG_BTRFS_FS_REF_VERIFY
346 Opt_ref_verify,
347#endif
348 Opt_err,
349};
350
351static const match_table_t tokens = {
352 {Opt_acl, "acl"},
353 {Opt_noacl, "noacl"},
354 {Opt_clear_cache, "clear_cache"},
355 {Opt_commit_interval, "commit=%u"},
356 {Opt_compress, "compress"},
357 {Opt_compress_type, "compress=%s"},
358 {Opt_compress_force, "compress-force"},
359 {Opt_compress_force_type, "compress-force=%s"},
360 {Opt_degraded, "degraded"},
361 {Opt_device, "device=%s"},
362 {Opt_fatal_errors, "fatal_errors=%s"},
363 {Opt_flushoncommit, "flushoncommit"},
364 {Opt_noflushoncommit, "noflushoncommit"},
365 {Opt_inode_cache, "inode_cache"},
366 {Opt_noinode_cache, "noinode_cache"},
367 {Opt_max_inline, "max_inline=%s"},
368 {Opt_barrier, "barrier"},
369 {Opt_nobarrier, "nobarrier"},
370 {Opt_datacow, "datacow"},
371 {Opt_nodatacow, "nodatacow"},
372 {Opt_datasum, "datasum"},
373 {Opt_nodatasum, "nodatasum"},
374 {Opt_defrag, "autodefrag"},
375 {Opt_nodefrag, "noautodefrag"},
376 {Opt_discard, "discard"},
377 {Opt_nodiscard, "nodiscard"},
378 {Opt_nologreplay, "nologreplay"},
379 {Opt_norecovery, "norecovery"},
380 {Opt_ratio, "metadata_ratio=%u"},
381 {Opt_rescan_uuid_tree, "rescan_uuid_tree"},
382 {Opt_skip_balance, "skip_balance"},
383 {Opt_space_cache, "space_cache"},
384 {Opt_no_space_cache, "nospace_cache"},
385 {Opt_space_cache_version, "space_cache=%s"},
386 {Opt_ssd, "ssd"},
387 {Opt_nossd, "nossd"},
388 {Opt_ssd_spread, "ssd_spread"},
389 {Opt_nossd_spread, "nossd_spread"},
390 {Opt_subvol, "subvol=%s"},
391 {Opt_subvolid, "subvolid=%s"},
392 {Opt_thread_pool, "thread_pool=%u"},
393 {Opt_treelog, "treelog"},
394 {Opt_notreelog, "notreelog"},
395 {Opt_usebackuproot, "usebackuproot"},
396 {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
397
398 /* Deprecated options */
399 {Opt_alloc_start, "alloc_start=%s"},
400 {Opt_recovery, "recovery"},
401 {Opt_subvolrootid, "subvolrootid=%d"},
402
403 /* Debugging options */
404 {Opt_check_integrity, "check_int"},
405 {Opt_check_integrity_including_extent_data, "check_int_data"},
406 {Opt_check_integrity_print_mask, "check_int_print_mask=%u"},
407 {Opt_enospc_debug, "enospc_debug"},
408 {Opt_noenospc_debug, "noenospc_debug"},
409#ifdef CONFIG_BTRFS_DEBUG
410 {Opt_fragment_data, "fragment=data"},
411 {Opt_fragment_metadata, "fragment=metadata"},
412 {Opt_fragment_all, "fragment=all"},
413#endif
414#ifdef CONFIG_BTRFS_FS_REF_VERIFY
415 {Opt_ref_verify, "ref_verify"},
416#endif
417 {Opt_err, NULL},
418};
419
420/*
421 * Regular mount options parser. Everything that is needed only when
422 * reading in a new superblock is parsed here.
423 * XXX JDM: This needs to be cleaned up for remount.
424 */
425int btrfs_parse_options(struct btrfs_fs_info *info, char *options,
426 unsigned long new_flags)
427{
428 substring_t args[MAX_OPT_ARGS];
429 char *p, *num;
430 u64 cache_gen;
431 int intarg;
432 int ret = 0;
433 char *compress_type;
434 bool compress_force = false;
435 enum btrfs_compression_type saved_compress_type;
436 bool saved_compress_force;
437 int no_compress = 0;
438
439 cache_gen = btrfs_super_cache_generation(info->super_copy);
440 if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE))
441 btrfs_set_opt(info->mount_opt, FREE_SPACE_TREE);
442 else if (cache_gen)
443 btrfs_set_opt(info->mount_opt, SPACE_CACHE);
444
445 /*
446 * Even the options are empty, we still need to do extra check
447 * against new flags
448 */
449 if (!options)
450 goto check;
451
452 while ((p = strsep(&options, ",")) != NULL) {
453 int token;
454 if (!*p)
455 continue;
456
457 token = match_token(p, tokens, args);
458 switch (token) {
459 case Opt_degraded:
460 btrfs_info(info, "allowing degraded mounts");
461 btrfs_set_opt(info->mount_opt, DEGRADED);
462 break;
463 case Opt_subvol:
464 case Opt_subvolid:
465 case Opt_subvolrootid:
466 case Opt_device:
467 /*
468 * These are parsed by btrfs_parse_subvol_options
469 * and btrfs_parse_early_options
470 * and can be happily ignored here.
471 */
472 break;
473 case Opt_nodatasum:
474 btrfs_set_and_info(info, NODATASUM,
475 "setting nodatasum");
476 break;
477 case Opt_datasum:
478 if (btrfs_test_opt(info, NODATASUM)) {
479 if (btrfs_test_opt(info, NODATACOW))
480 btrfs_info(info,
481 "setting datasum, datacow enabled");
482 else
483 btrfs_info(info, "setting datasum");
484 }
485 btrfs_clear_opt(info->mount_opt, NODATACOW);
486 btrfs_clear_opt(info->mount_opt, NODATASUM);
487 break;
488 case Opt_nodatacow:
489 if (!btrfs_test_opt(info, NODATACOW)) {
490 if (!btrfs_test_opt(info, COMPRESS) ||
491 !btrfs_test_opt(info, FORCE_COMPRESS)) {
492 btrfs_info(info,
493 "setting nodatacow, compression disabled");
494 } else {
495 btrfs_info(info, "setting nodatacow");
496 }
497 }
498 btrfs_clear_opt(info->mount_opt, COMPRESS);
499 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
500 btrfs_set_opt(info->mount_opt, NODATACOW);
501 btrfs_set_opt(info->mount_opt, NODATASUM);
502 break;
503 case Opt_datacow:
504 btrfs_clear_and_info(info, NODATACOW,
505 "setting datacow");
506 break;
507 case Opt_compress_force:
508 case Opt_compress_force_type:
509 compress_force = true;
510 /* Fallthrough */
511 case Opt_compress:
512 case Opt_compress_type:
513 saved_compress_type = btrfs_test_opt(info,
514 COMPRESS) ?
515 info->compress_type : BTRFS_COMPRESS_NONE;
516 saved_compress_force =
517 btrfs_test_opt(info, FORCE_COMPRESS);
518 if (token == Opt_compress ||
519 token == Opt_compress_force ||
520 strncmp(args[0].from, "zlib", 4) == 0) {
521 compress_type = "zlib";
522
523 info->compress_type = BTRFS_COMPRESS_ZLIB;
524 info->compress_level = BTRFS_ZLIB_DEFAULT_LEVEL;
525 /*
526 * args[0] contains uninitialized data since
527 * for these tokens we don't expect any
528 * parameter.
529 */
530 if (token != Opt_compress &&
531 token != Opt_compress_force)
532 info->compress_level =
533 btrfs_compress_str2level(args[0].from);
534 btrfs_set_opt(info->mount_opt, COMPRESS);
535 btrfs_clear_opt(info->mount_opt, NODATACOW);
536 btrfs_clear_opt(info->mount_opt, NODATASUM);
537 no_compress = 0;
538 } else if (strncmp(args[0].from, "lzo", 3) == 0) {
539 compress_type = "lzo";
540 info->compress_type = BTRFS_COMPRESS_LZO;
541 btrfs_set_opt(info->mount_opt, COMPRESS);
542 btrfs_clear_opt(info->mount_opt, NODATACOW);
543 btrfs_clear_opt(info->mount_opt, NODATASUM);
544 btrfs_set_fs_incompat(info, COMPRESS_LZO);
545 no_compress = 0;
546 } else if (strcmp(args[0].from, "zstd") == 0) {
547 compress_type = "zstd";
548 info->compress_type = BTRFS_COMPRESS_ZSTD;
549 btrfs_set_opt(info->mount_opt, COMPRESS);
550 btrfs_clear_opt(info->mount_opt, NODATACOW);
551 btrfs_clear_opt(info->mount_opt, NODATASUM);
552 btrfs_set_fs_incompat(info, COMPRESS_ZSTD);
553 no_compress = 0;
554 } else if (strncmp(args[0].from, "no", 2) == 0) {
555 compress_type = "no";
556 btrfs_clear_opt(info->mount_opt, COMPRESS);
557 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
558 compress_force = false;
559 no_compress++;
560 } else {
561 ret = -EINVAL;
562 goto out;
563 }
564
565 if (compress_force) {
566 btrfs_set_opt(info->mount_opt, FORCE_COMPRESS);
567 } else {
568 /*
569 * If we remount from compress-force=xxx to
570 * compress=xxx, we need clear FORCE_COMPRESS
571 * flag, otherwise, there is no way for users
572 * to disable forcible compression separately.
573 */
574 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
575 }
576 if ((btrfs_test_opt(info, COMPRESS) &&
577 (info->compress_type != saved_compress_type ||
578 compress_force != saved_compress_force)) ||
579 (!btrfs_test_opt(info, COMPRESS) &&
580 no_compress == 1)) {
581 btrfs_info(info, "%s %s compression, level %d",
582 (compress_force) ? "force" : "use",
583 compress_type, info->compress_level);
584 }
585 compress_force = false;
586 break;
587 case Opt_ssd:
588 btrfs_set_and_info(info, SSD,
589 "enabling ssd optimizations");
590 btrfs_clear_opt(info->mount_opt, NOSSD);
591 break;
592 case Opt_ssd_spread:
593 btrfs_set_and_info(info, SSD,
594 "enabling ssd optimizations");
595 btrfs_set_and_info(info, SSD_SPREAD,
596 "using spread ssd allocation scheme");
597 btrfs_clear_opt(info->mount_opt, NOSSD);
598 break;
599 case Opt_nossd:
600 btrfs_set_opt(info->mount_opt, NOSSD);
601 btrfs_clear_and_info(info, SSD,
602 "not using ssd optimizations");
603 /* Fallthrough */
604 case Opt_nossd_spread:
605 btrfs_clear_and_info(info, SSD_SPREAD,
606 "not using spread ssd allocation scheme");
607 break;
608 case Opt_barrier:
609 btrfs_clear_and_info(info, NOBARRIER,
610 "turning on barriers");
611 break;
612 case Opt_nobarrier:
613 btrfs_set_and_info(info, NOBARRIER,
614 "turning off barriers");
615 break;
616 case Opt_thread_pool:
617 ret = match_int(&args[0], &intarg);
618 if (ret) {
619 goto out;
620 } else if (intarg == 0) {
621 ret = -EINVAL;
622 goto out;
623 }
624 info->thread_pool_size = intarg;
625 break;
626 case Opt_max_inline:
627 num = match_strdup(&args[0]);
628 if (num) {
629 info->max_inline = memparse(num, NULL);
630 kfree(num);
631
632 if (info->max_inline) {
633 info->max_inline = min_t(u64,
634 info->max_inline,
635 info->sectorsize);
636 }
637 btrfs_info(info, "max_inline at %llu",
638 info->max_inline);
639 } else {
640 ret = -ENOMEM;
641 goto out;
642 }
643 break;
644 case Opt_alloc_start:
645 btrfs_info(info,
646 "option alloc_start is obsolete, ignored");
647 break;
648 case Opt_acl:
649#ifdef CONFIG_BTRFS_FS_POSIX_ACL
650 info->sb->s_flags |= SB_POSIXACL;
651 break;
652#else
653 btrfs_err(info, "support for ACL not compiled in!");
654 ret = -EINVAL;
655 goto out;
656#endif
657 case Opt_noacl:
658 info->sb->s_flags &= ~SB_POSIXACL;
659 break;
660 case Opt_notreelog:
661 btrfs_set_and_info(info, NOTREELOG,
662 "disabling tree log");
663 break;
664 case Opt_treelog:
665 btrfs_clear_and_info(info, NOTREELOG,
666 "enabling tree log");
667 break;
668 case Opt_norecovery:
669 case Opt_nologreplay:
670 btrfs_set_and_info(info, NOLOGREPLAY,
671 "disabling log replay at mount time");
672 break;
673 case Opt_flushoncommit:
674 btrfs_set_and_info(info, FLUSHONCOMMIT,
675 "turning on flush-on-commit");
676 break;
677 case Opt_noflushoncommit:
678 btrfs_clear_and_info(info, FLUSHONCOMMIT,
679 "turning off flush-on-commit");
680 break;
681 case Opt_ratio:
682 ret = match_int(&args[0], &intarg);
683 if (ret)
684 goto out;
685 info->metadata_ratio = intarg;
686 btrfs_info(info, "metadata ratio %u",
687 info->metadata_ratio);
688 break;
689 case Opt_discard:
690 btrfs_set_and_info(info, DISCARD,
691 "turning on discard");
692 break;
693 case Opt_nodiscard:
694 btrfs_clear_and_info(info, DISCARD,
695 "turning off discard");
696 break;
697 case Opt_space_cache:
698 case Opt_space_cache_version:
699 if (token == Opt_space_cache ||
700 strcmp(args[0].from, "v1") == 0) {
701 btrfs_clear_opt(info->mount_opt,
702 FREE_SPACE_TREE);
703 btrfs_set_and_info(info, SPACE_CACHE,
704 "enabling disk space caching");
705 } else if (strcmp(args[0].from, "v2") == 0) {
706 btrfs_clear_opt(info->mount_opt,
707 SPACE_CACHE);
708 btrfs_set_and_info(info, FREE_SPACE_TREE,
709 "enabling free space tree");
710 } else {
711 ret = -EINVAL;
712 goto out;
713 }
714 break;
715 case Opt_rescan_uuid_tree:
716 btrfs_set_opt(info->mount_opt, RESCAN_UUID_TREE);
717 break;
718 case Opt_no_space_cache:
719 if (btrfs_test_opt(info, SPACE_CACHE)) {
720 btrfs_clear_and_info(info, SPACE_CACHE,
721 "disabling disk space caching");
722 }
723 if (btrfs_test_opt(info, FREE_SPACE_TREE)) {
724 btrfs_clear_and_info(info, FREE_SPACE_TREE,
725 "disabling free space tree");
726 }
727 break;
728 case Opt_inode_cache:
729 btrfs_set_pending_and_info(info, INODE_MAP_CACHE,
730 "enabling inode map caching");
731 break;
732 case Opt_noinode_cache:
733 btrfs_clear_pending_and_info(info, INODE_MAP_CACHE,
734 "disabling inode map caching");
735 break;
736 case Opt_clear_cache:
737 btrfs_set_and_info(info, CLEAR_CACHE,
738 "force clearing of disk cache");
739 break;
740 case Opt_user_subvol_rm_allowed:
741 btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
742 break;
743 case Opt_enospc_debug:
744 btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
745 break;
746 case Opt_noenospc_debug:
747 btrfs_clear_opt(info->mount_opt, ENOSPC_DEBUG);
748 break;
749 case Opt_defrag:
750 btrfs_set_and_info(info, AUTO_DEFRAG,
751 "enabling auto defrag");
752 break;
753 case Opt_nodefrag:
754 btrfs_clear_and_info(info, AUTO_DEFRAG,
755 "disabling auto defrag");
756 break;
757 case Opt_recovery:
758 btrfs_warn(info,
759 "'recovery' is deprecated, use 'usebackuproot' instead");
760 case Opt_usebackuproot:
761 btrfs_info(info,
762 "trying to use backup root at mount time");
763 btrfs_set_opt(info->mount_opt, USEBACKUPROOT);
764 break;
765 case Opt_skip_balance:
766 btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
767 break;
768#ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
769 case Opt_check_integrity_including_extent_data:
770 btrfs_info(info,
771 "enabling check integrity including extent data");
772 btrfs_set_opt(info->mount_opt,
773 CHECK_INTEGRITY_INCLUDING_EXTENT_DATA);
774 btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
775 break;
776 case Opt_check_integrity:
777 btrfs_info(info, "enabling check integrity");
778 btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
779 break;
780 case Opt_check_integrity_print_mask:
781 ret = match_int(&args[0], &intarg);
782 if (ret)
783 goto out;
784 info->check_integrity_print_mask = intarg;
785 btrfs_info(info, "check_integrity_print_mask 0x%x",
786 info->check_integrity_print_mask);
787 break;
788#else
789 case Opt_check_integrity_including_extent_data:
790 case Opt_check_integrity:
791 case Opt_check_integrity_print_mask:
792 btrfs_err(info,
793 "support for check_integrity* not compiled in!");
794 ret = -EINVAL;
795 goto out;
796#endif
797 case Opt_fatal_errors:
798 if (strcmp(args[0].from, "panic") == 0)
799 btrfs_set_opt(info->mount_opt,
800 PANIC_ON_FATAL_ERROR);
801 else if (strcmp(args[0].from, "bug") == 0)
802 btrfs_clear_opt(info->mount_opt,
803 PANIC_ON_FATAL_ERROR);
804 else {
805 ret = -EINVAL;
806 goto out;
807 }
808 break;
809 case Opt_commit_interval:
810 intarg = 0;
811 ret = match_int(&args[0], &intarg);
812 if (ret)
813 goto out;
814 if (intarg == 0) {
815 btrfs_info(info,
816 "using default commit interval %us",
817 BTRFS_DEFAULT_COMMIT_INTERVAL);
818 intarg = BTRFS_DEFAULT_COMMIT_INTERVAL;
819 } else if (intarg > 300) {
820 btrfs_warn(info, "excessive commit interval %d",
821 intarg);
822 }
823 info->commit_interval = intarg;
824 break;
825#ifdef CONFIG_BTRFS_DEBUG
826 case Opt_fragment_all:
827 btrfs_info(info, "fragmenting all space");
828 btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
829 btrfs_set_opt(info->mount_opt, FRAGMENT_METADATA);
830 break;
831 case Opt_fragment_metadata:
832 btrfs_info(info, "fragmenting metadata");
833 btrfs_set_opt(info->mount_opt,
834 FRAGMENT_METADATA);
835 break;
836 case Opt_fragment_data:
837 btrfs_info(info, "fragmenting data");
838 btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
839 break;
840#endif
841#ifdef CONFIG_BTRFS_FS_REF_VERIFY
842 case Opt_ref_verify:
843 btrfs_info(info, "doing ref verification");
844 btrfs_set_opt(info->mount_opt, REF_VERIFY);
845 break;
846#endif
847 case Opt_err:
848 btrfs_info(info, "unrecognized mount option '%s'", p);
849 ret = -EINVAL;
850 goto out;
851 default:
852 break;
853 }
854 }
855check:
856 /*
857 * Extra check for current option against current flag
858 */
859 if (btrfs_test_opt(info, NOLOGREPLAY) && !(new_flags & SB_RDONLY)) {
860 btrfs_err(info,
861 "nologreplay must be used with ro mount option");
862 ret = -EINVAL;
863 }
864out:
865 if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE) &&
866 !btrfs_test_opt(info, FREE_SPACE_TREE) &&
867 !btrfs_test_opt(info, CLEAR_CACHE)) {
868 btrfs_err(info, "cannot disable free space tree");
869 ret = -EINVAL;
870
871 }
872 if (!ret && btrfs_test_opt(info, SPACE_CACHE))
873 btrfs_info(info, "disk space caching is enabled");
874 if (!ret && btrfs_test_opt(info, FREE_SPACE_TREE))
875 btrfs_info(info, "using free space tree");
876 return ret;
877}
878
879/*
880 * Parse mount options that are required early in the mount process.
881 *
882 * All other options will be parsed on much later in the mount process and
883 * only when we need to allocate a new super block.
884 */
885static int btrfs_parse_early_options(const char *options, fmode_t flags,
886 void *holder, struct btrfs_fs_devices **fs_devices)
887{
888 substring_t args[MAX_OPT_ARGS];
889 char *device_name, *opts, *orig, *p;
890 int error = 0;
891
892 if (!options)
893 return 0;
894
895 /*
896 * strsep changes the string, duplicate it because btrfs_parse_options
897 * gets called later
898 */
899 opts = kstrdup(options, GFP_KERNEL);
900 if (!opts)
901 return -ENOMEM;
902 orig = opts;
903
904 while ((p = strsep(&opts, ",")) != NULL) {
905 int token;
906
907 if (!*p)
908 continue;
909
910 token = match_token(p, tokens, args);
911 if (token == Opt_device) {
912 device_name = match_strdup(&args[0]);
913 if (!device_name) {
914 error = -ENOMEM;
915 goto out;
916 }
917 error = btrfs_scan_one_device(device_name,
918 flags, holder, fs_devices);
919 kfree(device_name);
920 if (error)
921 goto out;
922 }
923 }
924
925out:
926 kfree(orig);
927 return error;
928}
929
930/*
931 * Parse mount options that are related to subvolume id
932 *
933 * The value is later passed to mount_subvol()
934 */
935static int btrfs_parse_subvol_options(const char *options, fmode_t flags,
936 char **subvol_name, u64 *subvol_objectid)
937{
938 substring_t args[MAX_OPT_ARGS];
939 char *opts, *orig, *p;
940 int error = 0;
941 u64 subvolid;
942
943 if (!options)
944 return 0;
945
946 /*
947 * strsep changes the string, duplicate it because
948 * btrfs_parse_early_options gets called later
949 */
950 opts = kstrdup(options, GFP_KERNEL);
951 if (!opts)
952 return -ENOMEM;
953 orig = opts;
954
955 while ((p = strsep(&opts, ",")) != NULL) {
956 int token;
957 if (!*p)
958 continue;
959
960 token = match_token(p, tokens, args);
961 switch (token) {
962 case Opt_subvol:
963 kfree(*subvol_name);
964 *subvol_name = match_strdup(&args[0]);
965 if (!*subvol_name) {
966 error = -ENOMEM;
967 goto out;
968 }
969 break;
970 case Opt_subvolid:
971 error = match_u64(&args[0], &subvolid);
972 if (error)
973 goto out;
974
975 /* we want the original fs_tree */
976 if (subvolid == 0)
977 subvolid = BTRFS_FS_TREE_OBJECTID;
978
979 *subvol_objectid = subvolid;
980 break;
981 case Opt_subvolrootid:
982 pr_warn("BTRFS: 'subvolrootid' mount option is deprecated and has no effect\n");
983 break;
984 default:
985 break;
986 }
987 }
988
989out:
990 kfree(orig);
991 return error;
992}
993
994static char *get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
995 u64 subvol_objectid)
996{
997 struct btrfs_root *root = fs_info->tree_root;
998 struct btrfs_root *fs_root;
999 struct btrfs_root_ref *root_ref;
1000 struct btrfs_inode_ref *inode_ref;
1001 struct btrfs_key key;
1002 struct btrfs_path *path = NULL;
1003 char *name = NULL, *ptr;
1004 u64 dirid;
1005 int len;
1006 int ret;
1007
1008 path = btrfs_alloc_path();
1009 if (!path) {
1010 ret = -ENOMEM;
1011 goto err;
1012 }
1013 path->leave_spinning = 1;
1014
1015 name = kmalloc(PATH_MAX, GFP_KERNEL);
1016 if (!name) {
1017 ret = -ENOMEM;
1018 goto err;
1019 }
1020 ptr = name + PATH_MAX - 1;
1021 ptr[0] = '\0';
1022
1023 /*
1024 * Walk up the subvolume trees in the tree of tree roots by root
1025 * backrefs until we hit the top-level subvolume.
1026 */
1027 while (subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
1028 key.objectid = subvol_objectid;
1029 key.type = BTRFS_ROOT_BACKREF_KEY;
1030 key.offset = (u64)-1;
1031
1032 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1033 if (ret < 0) {
1034 goto err;
1035 } else if (ret > 0) {
1036 ret = btrfs_previous_item(root, path, subvol_objectid,
1037 BTRFS_ROOT_BACKREF_KEY);
1038 if (ret < 0) {
1039 goto err;
1040 } else if (ret > 0) {
1041 ret = -ENOENT;
1042 goto err;
1043 }
1044 }
1045
1046 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1047 subvol_objectid = key.offset;
1048
1049 root_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
1050 struct btrfs_root_ref);
1051 len = btrfs_root_ref_name_len(path->nodes[0], root_ref);
1052 ptr -= len + 1;
1053 if (ptr < name) {
1054 ret = -ENAMETOOLONG;
1055 goto err;
1056 }
1057 read_extent_buffer(path->nodes[0], ptr + 1,
1058 (unsigned long)(root_ref + 1), len);
1059 ptr[0] = '/';
1060 dirid = btrfs_root_ref_dirid(path->nodes[0], root_ref);
1061 btrfs_release_path(path);
1062
1063 key.objectid = subvol_objectid;
1064 key.type = BTRFS_ROOT_ITEM_KEY;
1065 key.offset = (u64)-1;
1066 fs_root = btrfs_read_fs_root_no_name(fs_info, &key);
1067 if (IS_ERR(fs_root)) {
1068 ret = PTR_ERR(fs_root);
1069 goto err;
1070 }
1071
1072 /*
1073 * Walk up the filesystem tree by inode refs until we hit the
1074 * root directory.
1075 */
1076 while (dirid != BTRFS_FIRST_FREE_OBJECTID) {
1077 key.objectid = dirid;
1078 key.type = BTRFS_INODE_REF_KEY;
1079 key.offset = (u64)-1;
1080
1081 ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0);
1082 if (ret < 0) {
1083 goto err;
1084 } else if (ret > 0) {
1085 ret = btrfs_previous_item(fs_root, path, dirid,
1086 BTRFS_INODE_REF_KEY);
1087 if (ret < 0) {
1088 goto err;
1089 } else if (ret > 0) {
1090 ret = -ENOENT;
1091 goto err;
1092 }
1093 }
1094
1095 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1096 dirid = key.offset;
1097
1098 inode_ref = btrfs_item_ptr(path->nodes[0],
1099 path->slots[0],
1100 struct btrfs_inode_ref);
1101 len = btrfs_inode_ref_name_len(path->nodes[0],
1102 inode_ref);
1103 ptr -= len + 1;
1104 if (ptr < name) {
1105 ret = -ENAMETOOLONG;
1106 goto err;
1107 }
1108 read_extent_buffer(path->nodes[0], ptr + 1,
1109 (unsigned long)(inode_ref + 1), len);
1110 ptr[0] = '/';
1111 btrfs_release_path(path);
1112 }
1113 }
1114
1115 btrfs_free_path(path);
1116 if (ptr == name + PATH_MAX - 1) {
1117 name[0] = '/';
1118 name[1] = '\0';
1119 } else {
1120 memmove(name, ptr, name + PATH_MAX - ptr);
1121 }
1122 return name;
1123
1124err:
1125 btrfs_free_path(path);
1126 kfree(name);
1127 return ERR_PTR(ret);
1128}
1129
1130static int get_default_subvol_objectid(struct btrfs_fs_info *fs_info, u64 *objectid)
1131{
1132 struct btrfs_root *root = fs_info->tree_root;
1133 struct btrfs_dir_item *di;
1134 struct btrfs_path *path;
1135 struct btrfs_key location;
1136 u64 dir_id;
1137
1138 path = btrfs_alloc_path();
1139 if (!path)
1140 return -ENOMEM;
1141 path->leave_spinning = 1;
1142
1143 /*
1144 * Find the "default" dir item which points to the root item that we
1145 * will mount by default if we haven't been given a specific subvolume
1146 * to mount.
1147 */
1148 dir_id = btrfs_super_root_dir(fs_info->super_copy);
1149 di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
1150 if (IS_ERR(di)) {
1151 btrfs_free_path(path);
1152 return PTR_ERR(di);
1153 }
1154 if (!di) {
1155 /*
1156 * Ok the default dir item isn't there. This is weird since
1157 * it's always been there, but don't freak out, just try and
1158 * mount the top-level subvolume.
1159 */
1160 btrfs_free_path(path);
1161 *objectid = BTRFS_FS_TREE_OBJECTID;
1162 return 0;
1163 }
1164
1165 btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
1166 btrfs_free_path(path);
1167 *objectid = location.objectid;
1168 return 0;
1169}
1170
1171static int btrfs_fill_super(struct super_block *sb,
1172 struct btrfs_fs_devices *fs_devices,
1173 void *data)
1174{
1175 struct inode *inode;
1176 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1177 struct btrfs_key key;
1178 int err;
1179
1180 sb->s_maxbytes = MAX_LFS_FILESIZE;
1181 sb->s_magic = BTRFS_SUPER_MAGIC;
1182 sb->s_op = &btrfs_super_ops;
1183 sb->s_d_op = &btrfs_dentry_operations;
1184 sb->s_export_op = &btrfs_export_ops;
1185 sb->s_xattr = btrfs_xattr_handlers;
1186 sb->s_time_gran = 1;
1187#ifdef CONFIG_BTRFS_FS_POSIX_ACL
1188 sb->s_flags |= SB_POSIXACL;
1189#endif
1190 sb->s_flags |= SB_I_VERSION;
1191 sb->s_iflags |= SB_I_CGROUPWB;
1192
1193 err = super_setup_bdi(sb);
1194 if (err) {
1195 btrfs_err(fs_info, "super_setup_bdi failed");
1196 return err;
1197 }
1198
1199 err = open_ctree(sb, fs_devices, (char *)data);
1200 if (err) {
1201 btrfs_err(fs_info, "open_ctree failed");
1202 return err;
1203 }
1204
1205 key.objectid = BTRFS_FIRST_FREE_OBJECTID;
1206 key.type = BTRFS_INODE_ITEM_KEY;
1207 key.offset = 0;
1208 inode = btrfs_iget(sb, &key, fs_info->fs_root, NULL);
1209 if (IS_ERR(inode)) {
1210 err = PTR_ERR(inode);
1211 goto fail_close;
1212 }
1213
1214 sb->s_root = d_make_root(inode);
1215 if (!sb->s_root) {
1216 err = -ENOMEM;
1217 goto fail_close;
1218 }
1219
1220 cleancache_init_fs(sb);
1221 sb->s_flags |= SB_ACTIVE;
1222 return 0;
1223
1224fail_close:
1225 close_ctree(fs_info);
1226 return err;
1227}
1228
1229int btrfs_sync_fs(struct super_block *sb, int wait)
1230{
1231 struct btrfs_trans_handle *trans;
1232 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1233 struct btrfs_root *root = fs_info->tree_root;
1234
1235 trace_btrfs_sync_fs(fs_info, wait);
1236
1237 if (!wait) {
1238 filemap_flush(fs_info->btree_inode->i_mapping);
1239 return 0;
1240 }
1241
1242 btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
1243
1244 trans = btrfs_attach_transaction_barrier(root);
1245 if (IS_ERR(trans)) {
1246 /* no transaction, don't bother */
1247 if (PTR_ERR(trans) == -ENOENT) {
1248 /*
1249 * Exit unless we have some pending changes
1250 * that need to go through commit
1251 */
1252 if (fs_info->pending_changes == 0)
1253 return 0;
1254 /*
1255 * A non-blocking test if the fs is frozen. We must not
1256 * start a new transaction here otherwise a deadlock
1257 * happens. The pending operations are delayed to the
1258 * next commit after thawing.
1259 */
1260 if (sb_start_write_trylock(sb))
1261 sb_end_write(sb);
1262 else
1263 return 0;
1264 trans = btrfs_start_transaction(root, 0);
1265 }
1266 if (IS_ERR(trans))
1267 return PTR_ERR(trans);
1268 }
1269 return btrfs_commit_transaction(trans);
1270}
1271
1272static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
1273{
1274 struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
1275 const char *compress_type;
1276
1277 if (btrfs_test_opt(info, DEGRADED))
1278 seq_puts(seq, ",degraded");
1279 if (btrfs_test_opt(info, NODATASUM))
1280 seq_puts(seq, ",nodatasum");
1281 if (btrfs_test_opt(info, NODATACOW))
1282 seq_puts(seq, ",nodatacow");
1283 if (btrfs_test_opt(info, NOBARRIER))
1284 seq_puts(seq, ",nobarrier");
1285 if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE)
1286 seq_printf(seq, ",max_inline=%llu", info->max_inline);
1287 if (info->thread_pool_size != min_t(unsigned long,
1288 num_online_cpus() + 2, 8))
1289 seq_printf(seq, ",thread_pool=%u", info->thread_pool_size);
1290 if (btrfs_test_opt(info, COMPRESS)) {
1291 compress_type = btrfs_compress_type2str(info->compress_type);
1292 if (btrfs_test_opt(info, FORCE_COMPRESS))
1293 seq_printf(seq, ",compress-force=%s", compress_type);
1294 else
1295 seq_printf(seq, ",compress=%s", compress_type);
1296 if (info->compress_level)
1297 seq_printf(seq, ":%d", info->compress_level);
1298 }
1299 if (btrfs_test_opt(info, NOSSD))
1300 seq_puts(seq, ",nossd");
1301 if (btrfs_test_opt(info, SSD_SPREAD))
1302 seq_puts(seq, ",ssd_spread");
1303 else if (btrfs_test_opt(info, SSD))
1304 seq_puts(seq, ",ssd");
1305 if (btrfs_test_opt(info, NOTREELOG))
1306 seq_puts(seq, ",notreelog");
1307 if (btrfs_test_opt(info, NOLOGREPLAY))
1308 seq_puts(seq, ",nologreplay");
1309 if (btrfs_test_opt(info, FLUSHONCOMMIT))
1310 seq_puts(seq, ",flushoncommit");
1311 if (btrfs_test_opt(info, DISCARD))
1312 seq_puts(seq, ",discard");
1313 if (!(info->sb->s_flags & SB_POSIXACL))
1314 seq_puts(seq, ",noacl");
1315 if (btrfs_test_opt(info, SPACE_CACHE))
1316 seq_puts(seq, ",space_cache");
1317 else if (btrfs_test_opt(info, FREE_SPACE_TREE))
1318 seq_puts(seq, ",space_cache=v2");
1319 else
1320 seq_puts(seq, ",nospace_cache");
1321 if (btrfs_test_opt(info, RESCAN_UUID_TREE))
1322 seq_puts(seq, ",rescan_uuid_tree");
1323 if (btrfs_test_opt(info, CLEAR_CACHE))
1324 seq_puts(seq, ",clear_cache");
1325 if (btrfs_test_opt(info, USER_SUBVOL_RM_ALLOWED))
1326 seq_puts(seq, ",user_subvol_rm_allowed");
1327 if (btrfs_test_opt(info, ENOSPC_DEBUG))
1328 seq_puts(seq, ",enospc_debug");
1329 if (btrfs_test_opt(info, AUTO_DEFRAG))
1330 seq_puts(seq, ",autodefrag");
1331 if (btrfs_test_opt(info, INODE_MAP_CACHE))
1332 seq_puts(seq, ",inode_cache");
1333 if (btrfs_test_opt(info, SKIP_BALANCE))
1334 seq_puts(seq, ",skip_balance");
1335#ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
1336 if (btrfs_test_opt(info, CHECK_INTEGRITY_INCLUDING_EXTENT_DATA))
1337 seq_puts(seq, ",check_int_data");
1338 else if (btrfs_test_opt(info, CHECK_INTEGRITY))
1339 seq_puts(seq, ",check_int");
1340 if (info->check_integrity_print_mask)
1341 seq_printf(seq, ",check_int_print_mask=%d",
1342 info->check_integrity_print_mask);
1343#endif
1344 if (info->metadata_ratio)
1345 seq_printf(seq, ",metadata_ratio=%u", info->metadata_ratio);
1346 if (btrfs_test_opt(info, PANIC_ON_FATAL_ERROR))
1347 seq_puts(seq, ",fatal_errors=panic");
1348 if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL)
1349 seq_printf(seq, ",commit=%u", info->commit_interval);
1350#ifdef CONFIG_BTRFS_DEBUG
1351 if (btrfs_test_opt(info, FRAGMENT_DATA))
1352 seq_puts(seq, ",fragment=data");
1353 if (btrfs_test_opt(info, FRAGMENT_METADATA))
1354 seq_puts(seq, ",fragment=metadata");
1355#endif
1356 if (btrfs_test_opt(info, REF_VERIFY))
1357 seq_puts(seq, ",ref_verify");
1358 seq_printf(seq, ",subvolid=%llu",
1359 BTRFS_I(d_inode(dentry))->root->root_key.objectid);
1360 seq_puts(seq, ",subvol=");
1361 seq_dentry(seq, dentry, " \t\n\\");
1362 return 0;
1363}
1364
1365static int btrfs_test_super(struct super_block *s, void *data)
1366{
1367 struct btrfs_fs_info *p = data;
1368 struct btrfs_fs_info *fs_info = btrfs_sb(s);
1369
1370 return fs_info->fs_devices == p->fs_devices;
1371}
1372
1373static int btrfs_set_super(struct super_block *s, void *data)
1374{
1375 int err = set_anon_super(s, data);
1376 if (!err)
1377 s->s_fs_info = data;
1378 return err;
1379}
1380
1381/*
1382 * subvolumes are identified by ino 256
1383 */
1384static inline int is_subvolume_inode(struct inode *inode)
1385{
1386 if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
1387 return 1;
1388 return 0;
1389}
1390
1391static struct dentry *mount_subvol(const char *subvol_name, u64 subvol_objectid,
1392 const char *device_name, struct vfsmount *mnt)
1393{
1394 struct dentry *root;
1395 int ret;
1396
1397 if (!subvol_name) {
1398 if (!subvol_objectid) {
1399 ret = get_default_subvol_objectid(btrfs_sb(mnt->mnt_sb),
1400 &subvol_objectid);
1401 if (ret) {
1402 root = ERR_PTR(ret);
1403 goto out;
1404 }
1405 }
1406 subvol_name = get_subvol_name_from_objectid(btrfs_sb(mnt->mnt_sb),
1407 subvol_objectid);
1408 if (IS_ERR(subvol_name)) {
1409 root = ERR_CAST(subvol_name);
1410 subvol_name = NULL;
1411 goto out;
1412 }
1413
1414 }
1415
1416 root = mount_subtree(mnt, subvol_name);
1417 /* mount_subtree() drops our reference on the vfsmount. */
1418 mnt = NULL;
1419
1420 if (!IS_ERR(root)) {
1421 struct super_block *s = root->d_sb;
1422 struct btrfs_fs_info *fs_info = btrfs_sb(s);
1423 struct inode *root_inode = d_inode(root);
1424 u64 root_objectid = BTRFS_I(root_inode)->root->root_key.objectid;
1425
1426 ret = 0;
1427 if (!is_subvolume_inode(root_inode)) {
1428 btrfs_err(fs_info, "'%s' is not a valid subvolume",
1429 subvol_name);
1430 ret = -EINVAL;
1431 }
1432 if (subvol_objectid && root_objectid != subvol_objectid) {
1433 /*
1434 * This will also catch a race condition where a
1435 * subvolume which was passed by ID is renamed and
1436 * another subvolume is renamed over the old location.
1437 */
1438 btrfs_err(fs_info,
1439 "subvol '%s' does not match subvolid %llu",
1440 subvol_name, subvol_objectid);
1441 ret = -EINVAL;
1442 }
1443 if (ret) {
1444 dput(root);
1445 root = ERR_PTR(ret);
1446 deactivate_locked_super(s);
1447 }
1448 }
1449
1450out:
1451 mntput(mnt);
1452 kfree(subvol_name);
1453 return root;
1454}
1455
1456static int parse_security_options(char *orig_opts,
1457 struct security_mnt_opts *sec_opts)
1458{
1459 char *secdata = NULL;
1460 int ret = 0;
1461
1462 secdata = alloc_secdata();
1463 if (!secdata)
1464 return -ENOMEM;
1465 ret = security_sb_copy_data(orig_opts, secdata);
1466 if (ret) {
1467 free_secdata(secdata);
1468 return ret;
1469 }
1470 ret = security_sb_parse_opts_str(secdata, sec_opts);
1471 free_secdata(secdata);
1472 return ret;
1473}
1474
1475static int setup_security_options(struct btrfs_fs_info *fs_info,
1476 struct super_block *sb,
1477 struct security_mnt_opts *sec_opts)
1478{
1479 int ret = 0;
1480
1481 /*
1482 * Call security_sb_set_mnt_opts() to check whether new sec_opts
1483 * is valid.
1484 */
1485 ret = security_sb_set_mnt_opts(sb, sec_opts, 0, NULL);
1486 if (ret)
1487 return ret;
1488
1489#ifdef CONFIG_SECURITY
1490 if (!fs_info->security_opts.num_mnt_opts) {
1491 /* first time security setup, copy sec_opts to fs_info */
1492 memcpy(&fs_info->security_opts, sec_opts, sizeof(*sec_opts));
1493 } else {
1494 /*
1495 * Since SELinux (the only one supporting security_mnt_opts)
1496 * does NOT support changing context during remount/mount of
1497 * the same sb, this must be the same or part of the same
1498 * security options, just free it.
1499 */
1500 security_free_mnt_opts(sec_opts);
1501 }
1502#endif
1503 return ret;
1504}
1505
1506/*
1507 * Find a superblock for the given device / mount point.
1508 *
1509 * Note: This is based on mount_bdev from fs/super.c with a few additions
1510 * for multiple device setup. Make sure to keep it in sync.
1511 */
1512static struct dentry *btrfs_mount_root(struct file_system_type *fs_type,
1513 int flags, const char *device_name, void *data)
1514{
1515 struct block_device *bdev = NULL;
1516 struct super_block *s;
1517 struct btrfs_fs_devices *fs_devices = NULL;
1518 struct btrfs_fs_info *fs_info = NULL;
1519 struct security_mnt_opts new_sec_opts;
1520 fmode_t mode = FMODE_READ;
1521 int error = 0;
1522
1523 if (!(flags & SB_RDONLY))
1524 mode |= FMODE_WRITE;
1525
1526 error = btrfs_parse_early_options(data, mode, fs_type,
1527 &fs_devices);
1528 if (error) {
1529 return ERR_PTR(error);
1530 }
1531
1532 security_init_mnt_opts(&new_sec_opts);
1533 if (data) {
1534 error = parse_security_options(data, &new_sec_opts);
1535 if (error)
1536 return ERR_PTR(error);
1537 }
1538
1539 error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices);
1540 if (error)
1541 goto error_sec_opts;
1542
1543 /*
1544 * Setup a dummy root and fs_info for test/set super. This is because
1545 * we don't actually fill this stuff out until open_ctree, but we need
1546 * it for searching for existing supers, so this lets us do that and
1547 * then open_ctree will properly initialize everything later.
1548 */
1549 fs_info = kvzalloc(sizeof(struct btrfs_fs_info), GFP_KERNEL);
1550 if (!fs_info) {
1551 error = -ENOMEM;
1552 goto error_sec_opts;
1553 }
1554
1555 fs_info->fs_devices = fs_devices;
1556
1557 fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
1558 fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
1559 security_init_mnt_opts(&fs_info->security_opts);
1560 if (!fs_info->super_copy || !fs_info->super_for_commit) {
1561 error = -ENOMEM;
1562 goto error_fs_info;
1563 }
1564
1565 error = btrfs_open_devices(fs_devices, mode, fs_type);
1566 if (error)
1567 goto error_fs_info;
1568
1569 if (!(flags & SB_RDONLY) && fs_devices->rw_devices == 0) {
1570 error = -EACCES;
1571 goto error_close_devices;
1572 }
1573
1574 bdev = fs_devices->latest_bdev;
1575 s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | SB_NOSEC,
1576 fs_info);
1577 if (IS_ERR(s)) {
1578 error = PTR_ERR(s);
1579 goto error_close_devices;
1580 }
1581
1582 if (s->s_root) {
1583 btrfs_close_devices(fs_devices);
1584 free_fs_info(fs_info);
1585 if ((flags ^ s->s_flags) & SB_RDONLY)
1586 error = -EBUSY;
1587 } else {
1588 snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev);
1589 btrfs_sb(s)->bdev_holder = fs_type;
1590 error = btrfs_fill_super(s, fs_devices, data);
1591 }
1592 if (error) {
1593 deactivate_locked_super(s);
1594 goto error_sec_opts;
1595 }
1596
1597 fs_info = btrfs_sb(s);
1598 error = setup_security_options(fs_info, s, &new_sec_opts);
1599 if (error) {
1600 deactivate_locked_super(s);
1601 goto error_sec_opts;
1602 }
1603
1604 return dget(s->s_root);
1605
1606error_close_devices:
1607 btrfs_close_devices(fs_devices);
1608error_fs_info:
1609 free_fs_info(fs_info);
1610error_sec_opts:
1611 security_free_mnt_opts(&new_sec_opts);
1612 return ERR_PTR(error);
1613}
1614
1615/*
1616 * Mount function which is called by VFS layer.
1617 *
1618 * In order to allow mounting a subvolume directly, btrfs uses mount_subtree()
1619 * which needs vfsmount* of device's root (/). This means device's root has to
1620 * be mounted internally in any case.
1621 *
1622 * Operation flow:
1623 * 1. Parse subvol id related options for later use in mount_subvol().
1624 *
1625 * 2. Mount device's root (/) by calling vfs_kern_mount().
1626 *
1627 * NOTE: vfs_kern_mount() is used by VFS to call btrfs_mount() in the
1628 * first place. In order to avoid calling btrfs_mount() again, we use
1629 * different file_system_type which is not registered to VFS by
1630 * register_filesystem() (btrfs_root_fs_type). As a result,
1631 * btrfs_mount_root() is called. The return value will be used by
1632 * mount_subtree() in mount_subvol().
1633 *
1634 * 3. Call mount_subvol() to get the dentry of subvolume. Since there is
1635 * "btrfs subvolume set-default", mount_subvol() is called always.
1636 */
1637static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
1638 const char *device_name, void *data)
1639{
1640 struct vfsmount *mnt_root;
1641 struct dentry *root;
1642 fmode_t mode = FMODE_READ;
1643 char *subvol_name = NULL;
1644 u64 subvol_objectid = 0;
1645 int error = 0;
1646
1647 if (!(flags & SB_RDONLY))
1648 mode |= FMODE_WRITE;
1649
1650 error = btrfs_parse_subvol_options(data, mode,
1651 &subvol_name, &subvol_objectid);
1652 if (error) {
1653 kfree(subvol_name);
1654 return ERR_PTR(error);
1655 }
1656
1657 /* mount device's root (/) */
1658 mnt_root = vfs_kern_mount(&btrfs_root_fs_type, flags, device_name, data);
1659 if (PTR_ERR_OR_ZERO(mnt_root) == -EBUSY) {
1660 if (flags & SB_RDONLY) {
1661 mnt_root = vfs_kern_mount(&btrfs_root_fs_type,
1662 flags & ~SB_RDONLY, device_name, data);
1663 } else {
1664 mnt_root = vfs_kern_mount(&btrfs_root_fs_type,
1665 flags | SB_RDONLY, device_name, data);
1666 if (IS_ERR(mnt_root)) {
1667 root = ERR_CAST(mnt_root);
1668 goto out;
1669 }
1670
1671 down_write(&mnt_root->mnt_sb->s_umount);
1672 error = btrfs_remount(mnt_root->mnt_sb, &flags, NULL);
1673 up_write(&mnt_root->mnt_sb->s_umount);
1674 if (error < 0) {
1675 root = ERR_PTR(error);
1676 mntput(mnt_root);
1677 goto out;
1678 }
1679 }
1680 }
1681 if (IS_ERR(mnt_root)) {
1682 root = ERR_CAST(mnt_root);
1683 goto out;
1684 }
1685
1686 /* mount_subvol() will free subvol_name and mnt_root */
1687 root = mount_subvol(subvol_name, subvol_objectid, device_name, mnt_root);
1688
1689out:
1690 return root;
1691}
1692
1693static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
1694 u32 new_pool_size, u32 old_pool_size)
1695{
1696 if (new_pool_size == old_pool_size)
1697 return;
1698
1699 fs_info->thread_pool_size = new_pool_size;
1700
1701 btrfs_info(fs_info, "resize thread pool %d -> %d",
1702 old_pool_size, new_pool_size);
1703
1704 btrfs_workqueue_set_max(fs_info->workers, new_pool_size);
1705 btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size);
1706 btrfs_workqueue_set_max(fs_info->submit_workers, new_pool_size);
1707 btrfs_workqueue_set_max(fs_info->caching_workers, new_pool_size);
1708 btrfs_workqueue_set_max(fs_info->endio_workers, new_pool_size);
1709 btrfs_workqueue_set_max(fs_info->endio_meta_workers, new_pool_size);
1710 btrfs_workqueue_set_max(fs_info->endio_meta_write_workers,
1711 new_pool_size);
1712 btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size);
1713 btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
1714 btrfs_workqueue_set_max(fs_info->delayed_workers, new_pool_size);
1715 btrfs_workqueue_set_max(fs_info->readahead_workers, new_pool_size);
1716 btrfs_workqueue_set_max(fs_info->scrub_wr_completion_workers,
1717 new_pool_size);
1718}
1719
1720static inline void btrfs_remount_prepare(struct btrfs_fs_info *fs_info)
1721{
1722 set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1723}
1724
1725static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info,
1726 unsigned long old_opts, int flags)
1727{
1728 if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1729 (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1730 (flags & SB_RDONLY))) {
1731 /* wait for any defraggers to finish */
1732 wait_event(fs_info->transaction_wait,
1733 (atomic_read(&fs_info->defrag_running) == 0));
1734 if (flags & SB_RDONLY)
1735 sync_filesystem(fs_info->sb);
1736 }
1737}
1738
1739static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
1740 unsigned long old_opts)
1741{
1742 /*
1743 * We need to cleanup all defragable inodes if the autodefragment is
1744 * close or the filesystem is read only.
1745 */
1746 if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1747 (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) || sb_rdonly(fs_info->sb))) {
1748 btrfs_cleanup_defrag_inodes(fs_info);
1749 }
1750
1751 clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1752}
1753
1754static int btrfs_remount(struct super_block *sb, int *flags, char *data)
1755{
1756 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1757 struct btrfs_root *root = fs_info->tree_root;
1758 unsigned old_flags = sb->s_flags;
1759 unsigned long old_opts = fs_info->mount_opt;
1760 unsigned long old_compress_type = fs_info->compress_type;
1761 u64 old_max_inline = fs_info->max_inline;
1762 u32 old_thread_pool_size = fs_info->thread_pool_size;
1763 u32 old_metadata_ratio = fs_info->metadata_ratio;
1764 int ret;
1765
1766 sync_filesystem(sb);
1767 btrfs_remount_prepare(fs_info);
1768
1769 if (data) {
1770 struct security_mnt_opts new_sec_opts;
1771
1772 security_init_mnt_opts(&new_sec_opts);
1773 ret = parse_security_options(data, &new_sec_opts);
1774 if (ret)
1775 goto restore;
1776 ret = setup_security_options(fs_info, sb,
1777 &new_sec_opts);
1778 if (ret) {
1779 security_free_mnt_opts(&new_sec_opts);
1780 goto restore;
1781 }
1782 }
1783
1784 ret = btrfs_parse_options(fs_info, data, *flags);
1785 if (ret) {
1786 ret = -EINVAL;
1787 goto restore;
1788 }
1789
1790 btrfs_remount_begin(fs_info, old_opts, *flags);
1791 btrfs_resize_thread_pool(fs_info,
1792 fs_info->thread_pool_size, old_thread_pool_size);
1793
1794 if ((bool)(*flags & SB_RDONLY) == sb_rdonly(sb))
1795 goto out;
1796
1797 if (*flags & SB_RDONLY) {
1798 /*
1799 * this also happens on 'umount -rf' or on shutdown, when
1800 * the filesystem is busy.
1801 */
1802 cancel_work_sync(&fs_info->async_reclaim_work);
1803
1804 /* wait for the uuid_scan task to finish */
1805 down(&fs_info->uuid_tree_rescan_sem);
1806 /* avoid complains from lockdep et al. */
1807 up(&fs_info->uuid_tree_rescan_sem);
1808
1809 sb->s_flags |= SB_RDONLY;
1810
1811 /*
1812 * Setting SB_RDONLY will put the cleaner thread to
1813 * sleep at the next loop if it's already active.
1814 * If it's already asleep, we'll leave unused block
1815 * groups on disk until we're mounted read-write again
1816 * unless we clean them up here.
1817 */
1818 btrfs_delete_unused_bgs(fs_info);
1819
1820 btrfs_dev_replace_suspend_for_unmount(fs_info);
1821 btrfs_scrub_cancel(fs_info);
1822 btrfs_pause_balance(fs_info);
1823
1824 ret = btrfs_commit_super(fs_info);
1825 if (ret)
1826 goto restore;
1827 } else {
1828 if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
1829 btrfs_err(fs_info,
1830 "Remounting read-write after error is not allowed");
1831 ret = -EINVAL;
1832 goto restore;
1833 }
1834 if (fs_info->fs_devices->rw_devices == 0) {
1835 ret = -EACCES;
1836 goto restore;
1837 }
1838
1839 if (!btrfs_check_rw_degradable(fs_info, NULL)) {
1840 btrfs_warn(fs_info,
1841 "too many missing devices, writeable remount is not allowed");
1842 ret = -EACCES;
1843 goto restore;
1844 }
1845
1846 if (btrfs_super_log_root(fs_info->super_copy) != 0) {
1847 ret = -EINVAL;
1848 goto restore;
1849 }
1850
1851 ret = btrfs_cleanup_fs_roots(fs_info);
1852 if (ret)
1853 goto restore;
1854
1855 /* recover relocation */
1856 mutex_lock(&fs_info->cleaner_mutex);
1857 ret = btrfs_recover_relocation(root);
1858 mutex_unlock(&fs_info->cleaner_mutex);
1859 if (ret)
1860 goto restore;
1861
1862 ret = btrfs_resume_balance_async(fs_info);
1863 if (ret)
1864 goto restore;
1865
1866 ret = btrfs_resume_dev_replace_async(fs_info);
1867 if (ret) {
1868 btrfs_warn(fs_info, "failed to resume dev_replace");
1869 goto restore;
1870 }
1871
1872 btrfs_qgroup_rescan_resume(fs_info);
1873
1874 if (!fs_info->uuid_root) {
1875 btrfs_info(fs_info, "creating UUID tree");
1876 ret = btrfs_create_uuid_tree(fs_info);
1877 if (ret) {
1878 btrfs_warn(fs_info,
1879 "failed to create the UUID tree %d",
1880 ret);
1881 goto restore;
1882 }
1883 }
1884 sb->s_flags &= ~SB_RDONLY;
1885
1886 set_bit(BTRFS_FS_OPEN, &fs_info->flags);
1887 }
1888out:
1889 wake_up_process(fs_info->transaction_kthread);
1890 btrfs_remount_cleanup(fs_info, old_opts);
1891 return 0;
1892
1893restore:
1894 /* We've hit an error - don't reset SB_RDONLY */
1895 if (sb_rdonly(sb))
1896 old_flags |= SB_RDONLY;
1897 sb->s_flags = old_flags;
1898 fs_info->mount_opt = old_opts;
1899 fs_info->compress_type = old_compress_type;
1900 fs_info->max_inline = old_max_inline;
1901 btrfs_resize_thread_pool(fs_info,
1902 old_thread_pool_size, fs_info->thread_pool_size);
1903 fs_info->metadata_ratio = old_metadata_ratio;
1904 btrfs_remount_cleanup(fs_info, old_opts);
1905 return ret;
1906}
1907
1908/* Used to sort the devices by max_avail(descending sort) */
1909static int btrfs_cmp_device_free_bytes(const void *dev_info1,
1910 const void *dev_info2)
1911{
1912 if (((struct btrfs_device_info *)dev_info1)->max_avail >
1913 ((struct btrfs_device_info *)dev_info2)->max_avail)
1914 return -1;
1915 else if (((struct btrfs_device_info *)dev_info1)->max_avail <
1916 ((struct btrfs_device_info *)dev_info2)->max_avail)
1917 return 1;
1918 else
1919 return 0;
1920}
1921
1922/*
1923 * sort the devices by max_avail, in which max free extent size of each device
1924 * is stored.(Descending Sort)
1925 */
1926static inline void btrfs_descending_sort_devices(
1927 struct btrfs_device_info *devices,
1928 size_t nr_devices)
1929{
1930 sort(devices, nr_devices, sizeof(struct btrfs_device_info),
1931 btrfs_cmp_device_free_bytes, NULL);
1932}
1933
1934/*
1935 * The helper to calc the free space on the devices that can be used to store
1936 * file data.
1937 */
1938static int btrfs_calc_avail_data_space(struct btrfs_fs_info *fs_info,
1939 u64 *free_bytes)
1940{
1941 struct btrfs_device_info *devices_info;
1942 struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
1943 struct btrfs_device *device;
1944 u64 skip_space;
1945 u64 type;
1946 u64 avail_space;
1947 u64 min_stripe_size;
1948 int min_stripes = 1, num_stripes = 1;
1949 int i = 0, nr_devices;
1950
1951 /*
1952 * We aren't under the device list lock, so this is racy-ish, but good
1953 * enough for our purposes.
1954 */
1955 nr_devices = fs_info->fs_devices->open_devices;
1956 if (!nr_devices) {
1957 smp_mb();
1958 nr_devices = fs_info->fs_devices->open_devices;
1959 ASSERT(nr_devices);
1960 if (!nr_devices) {
1961 *free_bytes = 0;
1962 return 0;
1963 }
1964 }
1965
1966 devices_info = kmalloc_array(nr_devices, sizeof(*devices_info),
1967 GFP_KERNEL);
1968 if (!devices_info)
1969 return -ENOMEM;
1970
1971 /* calc min stripe number for data space allocation */
1972 type = btrfs_data_alloc_profile(fs_info);
1973 if (type & BTRFS_BLOCK_GROUP_RAID0) {
1974 min_stripes = 2;
1975 num_stripes = nr_devices;
1976 } else if (type & BTRFS_BLOCK_GROUP_RAID1) {
1977 min_stripes = 2;
1978 num_stripes = 2;
1979 } else if (type & BTRFS_BLOCK_GROUP_RAID10) {
1980 min_stripes = 4;
1981 num_stripes = 4;
1982 }
1983
1984 if (type & BTRFS_BLOCK_GROUP_DUP)
1985 min_stripe_size = 2 * BTRFS_STRIPE_LEN;
1986 else
1987 min_stripe_size = BTRFS_STRIPE_LEN;
1988
1989 rcu_read_lock();
1990 list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
1991 if (!test_bit(BTRFS_DEV_STATE_IN_FS_METADATA,
1992 &device->dev_state) ||
1993 !device->bdev ||
1994 test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state))
1995 continue;
1996
1997 if (i >= nr_devices)
1998 break;
1999
2000 avail_space = device->total_bytes - device->bytes_used;
2001
2002 /* align with stripe_len */
2003 avail_space = div_u64(avail_space, BTRFS_STRIPE_LEN);
2004 avail_space *= BTRFS_STRIPE_LEN;
2005
2006 /*
2007 * In order to avoid overwriting the superblock on the drive,
2008 * btrfs starts at an offset of at least 1MB when doing chunk
2009 * allocation.
2010 */
2011 skip_space = SZ_1M;
2012
2013 /*
2014 * we can use the free space in [0, skip_space - 1], subtract
2015 * it from the total.
2016 */
2017 if (avail_space && avail_space >= skip_space)
2018 avail_space -= skip_space;
2019 else
2020 avail_space = 0;
2021
2022 if (avail_space < min_stripe_size)
2023 continue;
2024
2025 devices_info[i].dev = device;
2026 devices_info[i].max_avail = avail_space;
2027
2028 i++;
2029 }
2030 rcu_read_unlock();
2031
2032 nr_devices = i;
2033
2034 btrfs_descending_sort_devices(devices_info, nr_devices);
2035
2036 i = nr_devices - 1;
2037 avail_space = 0;
2038 while (nr_devices >= min_stripes) {
2039 if (num_stripes > nr_devices)
2040 num_stripes = nr_devices;
2041
2042 if (devices_info[i].max_avail >= min_stripe_size) {
2043 int j;
2044 u64 alloc_size;
2045
2046 avail_space += devices_info[i].max_avail * num_stripes;
2047 alloc_size = devices_info[i].max_avail;
2048 for (j = i + 1 - num_stripes; j <= i; j++)
2049 devices_info[j].max_avail -= alloc_size;
2050 }
2051 i--;
2052 nr_devices--;
2053 }
2054
2055 kfree(devices_info);
2056 *free_bytes = avail_space;
2057 return 0;
2058}
2059
2060/*
2061 * Calculate numbers for 'df', pessimistic in case of mixed raid profiles.
2062 *
2063 * If there's a redundant raid level at DATA block groups, use the respective
2064 * multiplier to scale the sizes.
2065 *
2066 * Unused device space usage is based on simulating the chunk allocator
2067 * algorithm that respects the device sizes and order of allocations. This is
2068 * a close approximation of the actual use but there are other factors that may
2069 * change the result (like a new metadata chunk).
2070 *
2071 * If metadata is exhausted, f_bavail will be 0.
2072 */
2073static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
2074{
2075 struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
2076 struct btrfs_super_block *disk_super = fs_info->super_copy;
2077 struct list_head *head = &fs_info->space_info;
2078 struct btrfs_space_info *found;
2079 u64 total_used = 0;
2080 u64 total_free_data = 0;
2081 u64 total_free_meta = 0;
2082 int bits = dentry->d_sb->s_blocksize_bits;
2083 __be32 *fsid = (__be32 *)fs_info->fsid;
2084 unsigned factor = 1;
2085 struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
2086 int ret;
2087 u64 thresh = 0;
2088 int mixed = 0;
2089
2090 rcu_read_lock();
2091 list_for_each_entry_rcu(found, head, list) {
2092 if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
2093 int i;
2094
2095 total_free_data += found->disk_total - found->disk_used;
2096 total_free_data -=
2097 btrfs_account_ro_block_groups_free_space(found);
2098
2099 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
2100 if (!list_empty(&found->block_groups[i])) {
2101 switch (i) {
2102 case BTRFS_RAID_DUP:
2103 case BTRFS_RAID_RAID1:
2104 case BTRFS_RAID_RAID10:
2105 factor = 2;
2106 }
2107 }
2108 }
2109 }
2110
2111 /*
2112 * Metadata in mixed block goup profiles are accounted in data
2113 */
2114 if (!mixed && found->flags & BTRFS_BLOCK_GROUP_METADATA) {
2115 if (found->flags & BTRFS_BLOCK_GROUP_DATA)
2116 mixed = 1;
2117 else
2118 total_free_meta += found->disk_total -
2119 found->disk_used;
2120 }
2121
2122 total_used += found->disk_used;
2123 }
2124
2125 rcu_read_unlock();
2126
2127 buf->f_blocks = div_u64(btrfs_super_total_bytes(disk_super), factor);
2128 buf->f_blocks >>= bits;
2129 buf->f_bfree = buf->f_blocks - (div_u64(total_used, factor) >> bits);
2130
2131 /* Account global block reserve as used, it's in logical size already */
2132 spin_lock(&block_rsv->lock);
2133 /* Mixed block groups accounting is not byte-accurate, avoid overflow */
2134 if (buf->f_bfree >= block_rsv->size >> bits)
2135 buf->f_bfree -= block_rsv->size >> bits;
2136 else
2137 buf->f_bfree = 0;
2138 spin_unlock(&block_rsv->lock);
2139
2140 buf->f_bavail = div_u64(total_free_data, factor);
2141 ret = btrfs_calc_avail_data_space(fs_info, &total_free_data);
2142 if (ret)
2143 return ret;
2144 buf->f_bavail += div_u64(total_free_data, factor);
2145 buf->f_bavail = buf->f_bavail >> bits;
2146
2147 /*
2148 * We calculate the remaining metadata space minus global reserve. If
2149 * this is (supposedly) smaller than zero, there's no space. But this
2150 * does not hold in practice, the exhausted state happens where's still
2151 * some positive delta. So we apply some guesswork and compare the
2152 * delta to a 4M threshold. (Practically observed delta was ~2M.)
2153 *
2154 * We probably cannot calculate the exact threshold value because this
2155 * depends on the internal reservations requested by various
2156 * operations, so some operations that consume a few metadata will
2157 * succeed even if the Avail is zero. But this is better than the other
2158 * way around.
2159 */
2160 thresh = SZ_4M;
2161
2162 if (!mixed && total_free_meta - thresh < block_rsv->size)
2163 buf->f_bavail = 0;
2164
2165 buf->f_type = BTRFS_SUPER_MAGIC;
2166 buf->f_bsize = dentry->d_sb->s_blocksize;
2167 buf->f_namelen = BTRFS_NAME_LEN;
2168
2169 /* We treat it as constant endianness (it doesn't matter _which_)
2170 because we want the fsid to come out the same whether mounted
2171 on a big-endian or little-endian host */
2172 buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
2173 buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
2174 /* Mask in the root object ID too, to disambiguate subvols */
2175 buf->f_fsid.val[0] ^= BTRFS_I(d_inode(dentry))->root->objectid >> 32;
2176 buf->f_fsid.val[1] ^= BTRFS_I(d_inode(dentry))->root->objectid;
2177
2178 return 0;
2179}
2180
2181static void btrfs_kill_super(struct super_block *sb)
2182{
2183 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2184 kill_anon_super(sb);
2185 free_fs_info(fs_info);
2186}
2187
2188static struct file_system_type btrfs_fs_type = {
2189 .owner = THIS_MODULE,
2190 .name = "btrfs",
2191 .mount = btrfs_mount,
2192 .kill_sb = btrfs_kill_super,
2193 .fs_flags = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,
2194};
2195
2196static struct file_system_type btrfs_root_fs_type = {
2197 .owner = THIS_MODULE,
2198 .name = "btrfs",
2199 .mount = btrfs_mount_root,
2200 .kill_sb = btrfs_kill_super,
2201 .fs_flags = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,
2202};
2203
2204MODULE_ALIAS_FS("btrfs");
2205
2206static int btrfs_control_open(struct inode *inode, struct file *file)
2207{
2208 /*
2209 * The control file's private_data is used to hold the
2210 * transaction when it is started and is used to keep
2211 * track of whether a transaction is already in progress.
2212 */
2213 file->private_data = NULL;
2214 return 0;
2215}
2216
2217/*
2218 * used by btrfsctl to scan devices when no FS is mounted
2219 */
2220static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
2221 unsigned long arg)
2222{
2223 struct btrfs_ioctl_vol_args *vol;
2224 struct btrfs_fs_devices *fs_devices;
2225 int ret = -ENOTTY;
2226
2227 if (!capable(CAP_SYS_ADMIN))
2228 return -EPERM;
2229
2230 vol = memdup_user((void __user *)arg, sizeof(*vol));
2231 if (IS_ERR(vol))
2232 return PTR_ERR(vol);
2233
2234 switch (cmd) {
2235 case BTRFS_IOC_SCAN_DEV:
2236 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
2237 &btrfs_root_fs_type, &fs_devices);
2238 break;
2239 case BTRFS_IOC_DEVICES_READY:
2240 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
2241 &btrfs_root_fs_type, &fs_devices);
2242 if (ret)
2243 break;
2244 ret = !(fs_devices->num_devices == fs_devices->total_devices);
2245 break;
2246 case BTRFS_IOC_GET_SUPPORTED_FEATURES:
2247 ret = btrfs_ioctl_get_supported_features((void __user*)arg);
2248 break;
2249 }
2250
2251 kfree(vol);
2252 return ret;
2253}
2254
2255static int btrfs_freeze(struct super_block *sb)
2256{
2257 struct btrfs_trans_handle *trans;
2258 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2259 struct btrfs_root *root = fs_info->tree_root;
2260
2261 set_bit(BTRFS_FS_FROZEN, &fs_info->flags);
2262 /*
2263 * We don't need a barrier here, we'll wait for any transaction that
2264 * could be in progress on other threads (and do delayed iputs that
2265 * we want to avoid on a frozen filesystem), or do the commit
2266 * ourselves.
2267 */
2268 trans = btrfs_attach_transaction_barrier(root);
2269 if (IS_ERR(trans)) {
2270 /* no transaction, don't bother */
2271 if (PTR_ERR(trans) == -ENOENT)
2272 return 0;
2273 return PTR_ERR(trans);
2274 }
2275 return btrfs_commit_transaction(trans);
2276}
2277
2278static int btrfs_unfreeze(struct super_block *sb)
2279{
2280 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2281
2282 clear_bit(BTRFS_FS_FROZEN, &fs_info->flags);
2283 return 0;
2284}
2285
2286static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
2287{
2288 struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
2289 struct btrfs_fs_devices *cur_devices;
2290 struct btrfs_device *dev, *first_dev = NULL;
2291 struct list_head *head;
2292 struct rcu_string *name;
2293
2294 /*
2295 * Lightweight locking of the devices. We should not need
2296 * device_list_mutex here as we only read the device data and the list
2297 * is protected by RCU. Even if a device is deleted during the list
2298 * traversals, we'll get valid data, the freeing callback will wait at
2299 * least until until the rcu_read_unlock.
2300 */
2301 rcu_read_lock();
2302 cur_devices = fs_info->fs_devices;
2303 while (cur_devices) {
2304 head = &cur_devices->devices;
2305 list_for_each_entry_rcu(dev, head, dev_list) {
2306 if (test_bit(BTRFS_DEV_STATE_MISSING, &dev->dev_state))
2307 continue;
2308 if (!dev->name)
2309 continue;
2310 if (!first_dev || dev->devid < first_dev->devid)
2311 first_dev = dev;
2312 }
2313 cur_devices = cur_devices->seed;
2314 }
2315
2316 if (first_dev) {
2317 name = rcu_dereference(first_dev->name);
2318 seq_escape(m, name->str, " \t\n\\");
2319 } else {
2320 WARN_ON(1);
2321 }
2322 rcu_read_unlock();
2323 return 0;
2324}
2325
2326static const struct super_operations btrfs_super_ops = {
2327 .drop_inode = btrfs_drop_inode,
2328 .evict_inode = btrfs_evict_inode,
2329 .put_super = btrfs_put_super,
2330 .sync_fs = btrfs_sync_fs,
2331 .show_options = btrfs_show_options,
2332 .show_devname = btrfs_show_devname,
2333 .write_inode = btrfs_write_inode,
2334 .alloc_inode = btrfs_alloc_inode,
2335 .destroy_inode = btrfs_destroy_inode,
2336 .statfs = btrfs_statfs,
2337 .remount_fs = btrfs_remount,
2338 .freeze_fs = btrfs_freeze,
2339 .unfreeze_fs = btrfs_unfreeze,
2340};
2341
2342static const struct file_operations btrfs_ctl_fops = {
2343 .open = btrfs_control_open,
2344 .unlocked_ioctl = btrfs_control_ioctl,
2345 .compat_ioctl = btrfs_control_ioctl,
2346 .owner = THIS_MODULE,
2347 .llseek = noop_llseek,
2348};
2349
2350static struct miscdevice btrfs_misc = {
2351 .minor = BTRFS_MINOR,
2352 .name = "btrfs-control",
2353 .fops = &btrfs_ctl_fops
2354};
2355
2356MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
2357MODULE_ALIAS("devname:btrfs-control");
2358
2359static int __init btrfs_interface_init(void)
2360{
2361 return misc_register(&btrfs_misc);
2362}
2363
2364static __cold void btrfs_interface_exit(void)
2365{
2366 misc_deregister(&btrfs_misc);
2367}
2368
2369static void __init btrfs_print_mod_info(void)
2370{
2371 pr_info("Btrfs loaded, crc32c=%s"
2372#ifdef CONFIG_BTRFS_DEBUG
2373 ", debug=on"
2374#endif
2375#ifdef CONFIG_BTRFS_ASSERT
2376 ", assert=on"
2377#endif
2378#ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
2379 ", integrity-checker=on"
2380#endif
2381#ifdef CONFIG_BTRFS_FS_REF_VERIFY
2382 ", ref-verify=on"
2383#endif
2384 "\n",
2385 crc32c_impl());
2386}
2387
2388static int __init init_btrfs_fs(void)
2389{
2390 int err;
2391
2392 btrfs_props_init();
2393
2394 err = btrfs_init_sysfs();
2395 if (err)
2396 return err;
2397
2398 btrfs_init_compress();
2399
2400 err = btrfs_init_cachep();
2401 if (err)
2402 goto free_compress;
2403
2404 err = extent_io_init();
2405 if (err)
2406 goto free_cachep;
2407
2408 err = extent_map_init();
2409 if (err)
2410 goto free_extent_io;
2411
2412 err = ordered_data_init();
2413 if (err)
2414 goto free_extent_map;
2415
2416 err = btrfs_delayed_inode_init();
2417 if (err)
2418 goto free_ordered_data;
2419
2420 err = btrfs_auto_defrag_init();
2421 if (err)
2422 goto free_delayed_inode;
2423
2424 err = btrfs_delayed_ref_init();
2425 if (err)
2426 goto free_auto_defrag;
2427
2428 err = btrfs_prelim_ref_init();
2429 if (err)
2430 goto free_delayed_ref;
2431
2432 err = btrfs_end_io_wq_init();
2433 if (err)
2434 goto free_prelim_ref;
2435
2436 err = btrfs_interface_init();
2437 if (err)
2438 goto free_end_io_wq;
2439
2440 btrfs_init_lockdep();
2441
2442 btrfs_print_mod_info();
2443
2444 err = btrfs_run_sanity_tests();
2445 if (err)
2446 goto unregister_ioctl;
2447
2448 err = register_filesystem(&btrfs_fs_type);
2449 if (err)
2450 goto unregister_ioctl;
2451
2452 return 0;
2453
2454unregister_ioctl:
2455 btrfs_interface_exit();
2456free_end_io_wq:
2457 btrfs_end_io_wq_exit();
2458free_prelim_ref:
2459 btrfs_prelim_ref_exit();
2460free_delayed_ref:
2461 btrfs_delayed_ref_exit();
2462free_auto_defrag:
2463 btrfs_auto_defrag_exit();
2464free_delayed_inode:
2465 btrfs_delayed_inode_exit();
2466free_ordered_data:
2467 ordered_data_exit();
2468free_extent_map:
2469 extent_map_exit();
2470free_extent_io:
2471 extent_io_exit();
2472free_cachep:
2473 btrfs_destroy_cachep();
2474free_compress:
2475 btrfs_exit_compress();
2476 btrfs_exit_sysfs();
2477
2478 return err;
2479}
2480
2481static void __exit exit_btrfs_fs(void)
2482{
2483 btrfs_destroy_cachep();
2484 btrfs_delayed_ref_exit();
2485 btrfs_auto_defrag_exit();
2486 btrfs_delayed_inode_exit();
2487 btrfs_prelim_ref_exit();
2488 ordered_data_exit();
2489 extent_map_exit();
2490 extent_io_exit();
2491 btrfs_interface_exit();
2492 btrfs_end_io_wq_exit();
2493 unregister_filesystem(&btrfs_fs_type);
2494 btrfs_exit_sysfs();
2495 btrfs_cleanup_fs_uuids();
2496 btrfs_exit_compress();
2497}
2498
2499late_initcall(init_btrfs_fs);
2500module_exit(exit_btrfs_fs)
2501
2502MODULE_LICENSE("GPL");