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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/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 "props.h"
38#include "xattr.h"
39#include "bio.h"
40#include "export.h"
41#include "compression.h"
42#include "dev-replace.h"
43#include "free-space-cache.h"
44#include "backref.h"
45#include "space-info.h"
46#include "sysfs.h"
47#include "zoned.h"
48#include "tests/btrfs-tests.h"
49#include "block-group.h"
50#include "discard.h"
51#include "qgroup.h"
52#include "raid56.h"
53#include "fs.h"
54#include "accessors.h"
55#include "defrag.h"
56#include "dir-item.h"
57#include "ioctl.h"
58#include "scrub.h"
59#include "verity.h"
60#include "super.h"
61#include "extent-tree.h"
62#define CREATE_TRACE_POINTS
63#include <trace/events/btrfs.h>
64
65static const struct super_operations btrfs_super_ops;
66static struct file_system_type btrfs_fs_type;
67
68static void btrfs_put_super(struct super_block *sb)
69{
70 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
71
72 btrfs_info(fs_info, "last unmount of filesystem %pU", fs_info->fs_devices->fsid);
73 close_ctree(fs_info);
74}
75
76/* Store the mount options related information. */
77struct btrfs_fs_context {
78 char *subvol_name;
79 u64 subvol_objectid;
80 u64 max_inline;
81 u32 commit_interval;
82 u32 metadata_ratio;
83 u32 thread_pool_size;
84 unsigned long mount_opt;
85 unsigned long compress_type:4;
86 unsigned int compress_level;
87 refcount_t refs;
88};
89
90enum {
91 Opt_acl,
92 Opt_clear_cache,
93 Opt_commit_interval,
94 Opt_compress,
95 Opt_compress_force,
96 Opt_compress_force_type,
97 Opt_compress_type,
98 Opt_degraded,
99 Opt_device,
100 Opt_fatal_errors,
101 Opt_flushoncommit,
102 Opt_max_inline,
103 Opt_barrier,
104 Opt_datacow,
105 Opt_datasum,
106 Opt_defrag,
107 Opt_discard,
108 Opt_discard_mode,
109 Opt_ratio,
110 Opt_rescan_uuid_tree,
111 Opt_skip_balance,
112 Opt_space_cache,
113 Opt_space_cache_version,
114 Opt_ssd,
115 Opt_ssd_spread,
116 Opt_subvol,
117 Opt_subvol_empty,
118 Opt_subvolid,
119 Opt_thread_pool,
120 Opt_treelog,
121 Opt_user_subvol_rm_allowed,
122
123 /* Rescue options */
124 Opt_rescue,
125 Opt_usebackuproot,
126 Opt_nologreplay,
127 Opt_ignorebadroots,
128 Opt_ignoredatacsums,
129 Opt_rescue_all,
130
131 /* Debugging options */
132 Opt_enospc_debug,
133#ifdef CONFIG_BTRFS_DEBUG
134 Opt_fragment, Opt_fragment_data, Opt_fragment_metadata, Opt_fragment_all,
135#endif
136#ifdef CONFIG_BTRFS_FS_REF_VERIFY
137 Opt_ref_verify,
138#endif
139 Opt_err,
140};
141
142enum {
143 Opt_fatal_errors_panic,
144 Opt_fatal_errors_bug,
145};
146
147static const struct constant_table btrfs_parameter_fatal_errors[] = {
148 { "panic", Opt_fatal_errors_panic },
149 { "bug", Opt_fatal_errors_bug },
150 {}
151};
152
153enum {
154 Opt_discard_sync,
155 Opt_discard_async,
156};
157
158static const struct constant_table btrfs_parameter_discard[] = {
159 { "sync", Opt_discard_sync },
160 { "async", Opt_discard_async },
161 {}
162};
163
164enum {
165 Opt_space_cache_v1,
166 Opt_space_cache_v2,
167};
168
169static const struct constant_table btrfs_parameter_space_cache[] = {
170 { "v1", Opt_space_cache_v1 },
171 { "v2", Opt_space_cache_v2 },
172 {}
173};
174
175enum {
176 Opt_rescue_usebackuproot,
177 Opt_rescue_nologreplay,
178 Opt_rescue_ignorebadroots,
179 Opt_rescue_ignoredatacsums,
180 Opt_rescue_parameter_all,
181};
182
183static const struct constant_table btrfs_parameter_rescue[] = {
184 { "usebackuproot", Opt_rescue_usebackuproot },
185 { "nologreplay", Opt_rescue_nologreplay },
186 { "ignorebadroots", Opt_rescue_ignorebadroots },
187 { "ibadroots", Opt_rescue_ignorebadroots },
188 { "ignoredatacsums", Opt_rescue_ignoredatacsums },
189 { "idatacsums", Opt_rescue_ignoredatacsums },
190 { "all", Opt_rescue_parameter_all },
191 {}
192};
193
194#ifdef CONFIG_BTRFS_DEBUG
195enum {
196 Opt_fragment_parameter_data,
197 Opt_fragment_parameter_metadata,
198 Opt_fragment_parameter_all,
199};
200
201static const struct constant_table btrfs_parameter_fragment[] = {
202 { "data", Opt_fragment_parameter_data },
203 { "metadata", Opt_fragment_parameter_metadata },
204 { "all", Opt_fragment_parameter_all },
205 {}
206};
207#endif
208
209static const struct fs_parameter_spec btrfs_fs_parameters[] = {
210 fsparam_flag_no("acl", Opt_acl),
211 fsparam_flag_no("autodefrag", Opt_defrag),
212 fsparam_flag_no("barrier", Opt_barrier),
213 fsparam_flag("clear_cache", Opt_clear_cache),
214 fsparam_u32("commit", Opt_commit_interval),
215 fsparam_flag("compress", Opt_compress),
216 fsparam_string("compress", Opt_compress_type),
217 fsparam_flag("compress-force", Opt_compress_force),
218 fsparam_string("compress-force", Opt_compress_force_type),
219 fsparam_flag_no("datacow", Opt_datacow),
220 fsparam_flag_no("datasum", Opt_datasum),
221 fsparam_flag("degraded", Opt_degraded),
222 fsparam_string("device", Opt_device),
223 fsparam_flag_no("discard", Opt_discard),
224 fsparam_enum("discard", Opt_discard_mode, btrfs_parameter_discard),
225 fsparam_enum("fatal_errors", Opt_fatal_errors, btrfs_parameter_fatal_errors),
226 fsparam_flag_no("flushoncommit", Opt_flushoncommit),
227 fsparam_string("max_inline", Opt_max_inline),
228 fsparam_u32("metadata_ratio", Opt_ratio),
229 fsparam_flag("rescan_uuid_tree", Opt_rescan_uuid_tree),
230 fsparam_flag("skip_balance", Opt_skip_balance),
231 fsparam_flag_no("space_cache", Opt_space_cache),
232 fsparam_enum("space_cache", Opt_space_cache_version, btrfs_parameter_space_cache),
233 fsparam_flag_no("ssd", Opt_ssd),
234 fsparam_flag_no("ssd_spread", Opt_ssd_spread),
235 fsparam_string("subvol", Opt_subvol),
236 fsparam_flag("subvol=", Opt_subvol_empty),
237 fsparam_u64("subvolid", Opt_subvolid),
238 fsparam_u32("thread_pool", Opt_thread_pool),
239 fsparam_flag_no("treelog", Opt_treelog),
240 fsparam_flag("user_subvol_rm_allowed", Opt_user_subvol_rm_allowed),
241
242 /* Rescue options. */
243 fsparam_enum("rescue", Opt_rescue, btrfs_parameter_rescue),
244 /* Deprecated, with alias rescue=nologreplay */
245 __fsparam(NULL, "nologreplay", Opt_nologreplay, fs_param_deprecated, NULL),
246 /* Deprecated, with alias rescue=usebackuproot */
247 __fsparam(NULL, "usebackuproot", Opt_usebackuproot, fs_param_deprecated, NULL),
248
249 /* Debugging options. */
250 fsparam_flag_no("enospc_debug", Opt_enospc_debug),
251#ifdef CONFIG_BTRFS_DEBUG
252 fsparam_enum("fragment", Opt_fragment, btrfs_parameter_fragment),
253#endif
254#ifdef CONFIG_BTRFS_FS_REF_VERIFY
255 fsparam_flag("ref_verify", Opt_ref_verify),
256#endif
257 {}
258};
259
260/* No support for restricting writes to btrfs devices yet... */
261static inline blk_mode_t btrfs_open_mode(struct fs_context *fc)
262{
263 return sb_open_mode(fc->sb_flags) & ~BLK_OPEN_RESTRICT_WRITES;
264}
265
266static int btrfs_parse_param(struct fs_context *fc, struct fs_parameter *param)
267{
268 struct btrfs_fs_context *ctx = fc->fs_private;
269 struct fs_parse_result result;
270 int opt;
271
272 opt = fs_parse(fc, btrfs_fs_parameters, param, &result);
273 if (opt < 0)
274 return opt;
275
276 switch (opt) {
277 case Opt_degraded:
278 btrfs_set_opt(ctx->mount_opt, DEGRADED);
279 break;
280 case Opt_subvol_empty:
281 /*
282 * This exists because we used to allow it on accident, so we're
283 * keeping it to maintain ABI. See 37becec95ac3 ("Btrfs: allow
284 * empty subvol= again").
285 */
286 break;
287 case Opt_subvol:
288 kfree(ctx->subvol_name);
289 ctx->subvol_name = kstrdup(param->string, GFP_KERNEL);
290 if (!ctx->subvol_name)
291 return -ENOMEM;
292 break;
293 case Opt_subvolid:
294 ctx->subvol_objectid = result.uint_64;
295
296 /* subvolid=0 means give me the original fs_tree. */
297 if (!ctx->subvol_objectid)
298 ctx->subvol_objectid = BTRFS_FS_TREE_OBJECTID;
299 break;
300 case Opt_device: {
301 struct btrfs_device *device;
302 blk_mode_t mode = btrfs_open_mode(fc);
303
304 mutex_lock(&uuid_mutex);
305 device = btrfs_scan_one_device(param->string, mode, false);
306 mutex_unlock(&uuid_mutex);
307 if (IS_ERR(device))
308 return PTR_ERR(device);
309 break;
310 }
311 case Opt_datasum:
312 if (result.negated) {
313 btrfs_set_opt(ctx->mount_opt, NODATASUM);
314 } else {
315 btrfs_clear_opt(ctx->mount_opt, NODATACOW);
316 btrfs_clear_opt(ctx->mount_opt, NODATASUM);
317 }
318 break;
319 case Opt_datacow:
320 if (result.negated) {
321 btrfs_clear_opt(ctx->mount_opt, COMPRESS);
322 btrfs_clear_opt(ctx->mount_opt, FORCE_COMPRESS);
323 btrfs_set_opt(ctx->mount_opt, NODATACOW);
324 btrfs_set_opt(ctx->mount_opt, NODATASUM);
325 } else {
326 btrfs_clear_opt(ctx->mount_opt, NODATACOW);
327 }
328 break;
329 case Opt_compress_force:
330 case Opt_compress_force_type:
331 btrfs_set_opt(ctx->mount_opt, FORCE_COMPRESS);
332 fallthrough;
333 case Opt_compress:
334 case Opt_compress_type:
335 if (opt == Opt_compress || opt == Opt_compress_force) {
336 ctx->compress_type = BTRFS_COMPRESS_ZLIB;
337 ctx->compress_level = BTRFS_ZLIB_DEFAULT_LEVEL;
338 btrfs_set_opt(ctx->mount_opt, COMPRESS);
339 btrfs_clear_opt(ctx->mount_opt, NODATACOW);
340 btrfs_clear_opt(ctx->mount_opt, NODATASUM);
341 } else if (strncmp(param->string, "zlib", 4) == 0) {
342 ctx->compress_type = BTRFS_COMPRESS_ZLIB;
343 ctx->compress_level =
344 btrfs_compress_str2level(BTRFS_COMPRESS_ZLIB,
345 param->string + 4);
346 btrfs_set_opt(ctx->mount_opt, COMPRESS);
347 btrfs_clear_opt(ctx->mount_opt, NODATACOW);
348 btrfs_clear_opt(ctx->mount_opt, NODATASUM);
349 } else if (strncmp(param->string, "lzo", 3) == 0) {
350 ctx->compress_type = BTRFS_COMPRESS_LZO;
351 ctx->compress_level = 0;
352 btrfs_set_opt(ctx->mount_opt, COMPRESS);
353 btrfs_clear_opt(ctx->mount_opt, NODATACOW);
354 btrfs_clear_opt(ctx->mount_opt, NODATASUM);
355 } else if (strncmp(param->string, "zstd", 4) == 0) {
356 ctx->compress_type = BTRFS_COMPRESS_ZSTD;
357 ctx->compress_level =
358 btrfs_compress_str2level(BTRFS_COMPRESS_ZSTD,
359 param->string + 4);
360 btrfs_set_opt(ctx->mount_opt, COMPRESS);
361 btrfs_clear_opt(ctx->mount_opt, NODATACOW);
362 btrfs_clear_opt(ctx->mount_opt, NODATASUM);
363 } else if (strncmp(param->string, "no", 2) == 0) {
364 ctx->compress_level = 0;
365 ctx->compress_type = 0;
366 btrfs_clear_opt(ctx->mount_opt, COMPRESS);
367 btrfs_clear_opt(ctx->mount_opt, FORCE_COMPRESS);
368 } else {
369 btrfs_err(NULL, "unrecognized compression value %s",
370 param->string);
371 return -EINVAL;
372 }
373 break;
374 case Opt_ssd:
375 if (result.negated) {
376 btrfs_set_opt(ctx->mount_opt, NOSSD);
377 btrfs_clear_opt(ctx->mount_opt, SSD);
378 btrfs_clear_opt(ctx->mount_opt, SSD_SPREAD);
379 } else {
380 btrfs_set_opt(ctx->mount_opt, SSD);
381 btrfs_clear_opt(ctx->mount_opt, NOSSD);
382 }
383 break;
384 case Opt_ssd_spread:
385 if (result.negated) {
386 btrfs_clear_opt(ctx->mount_opt, SSD_SPREAD);
387 } else {
388 btrfs_set_opt(ctx->mount_opt, SSD);
389 btrfs_set_opt(ctx->mount_opt, SSD_SPREAD);
390 btrfs_clear_opt(ctx->mount_opt, NOSSD);
391 }
392 break;
393 case Opt_barrier:
394 if (result.negated)
395 btrfs_set_opt(ctx->mount_opt, NOBARRIER);
396 else
397 btrfs_clear_opt(ctx->mount_opt, NOBARRIER);
398 break;
399 case Opt_thread_pool:
400 if (result.uint_32 == 0) {
401 btrfs_err(NULL, "invalid value 0 for thread_pool");
402 return -EINVAL;
403 }
404 ctx->thread_pool_size = result.uint_32;
405 break;
406 case Opt_max_inline:
407 ctx->max_inline = memparse(param->string, NULL);
408 break;
409 case Opt_acl:
410 if (result.negated) {
411 fc->sb_flags &= ~SB_POSIXACL;
412 } else {
413#ifdef CONFIG_BTRFS_FS_POSIX_ACL
414 fc->sb_flags |= SB_POSIXACL;
415#else
416 btrfs_err(NULL, "support for ACL not compiled in");
417 return -EINVAL;
418#endif
419 }
420 /*
421 * VFS limits the ability to toggle ACL on and off via remount,
422 * despite every file system allowing this. This seems to be
423 * an oversight since we all do, but it'll fail if we're
424 * remounting. So don't set the mask here, we'll check it in
425 * btrfs_reconfigure and do the toggling ourselves.
426 */
427 if (fc->purpose != FS_CONTEXT_FOR_RECONFIGURE)
428 fc->sb_flags_mask |= SB_POSIXACL;
429 break;
430 case Opt_treelog:
431 if (result.negated)
432 btrfs_set_opt(ctx->mount_opt, NOTREELOG);
433 else
434 btrfs_clear_opt(ctx->mount_opt, NOTREELOG);
435 break;
436 case Opt_nologreplay:
437 btrfs_warn(NULL,
438 "'nologreplay' is deprecated, use 'rescue=nologreplay' instead");
439 btrfs_set_opt(ctx->mount_opt, NOLOGREPLAY);
440 break;
441 case Opt_flushoncommit:
442 if (result.negated)
443 btrfs_clear_opt(ctx->mount_opt, FLUSHONCOMMIT);
444 else
445 btrfs_set_opt(ctx->mount_opt, FLUSHONCOMMIT);
446 break;
447 case Opt_ratio:
448 ctx->metadata_ratio = result.uint_32;
449 break;
450 case Opt_discard:
451 if (result.negated) {
452 btrfs_clear_opt(ctx->mount_opt, DISCARD_SYNC);
453 btrfs_clear_opt(ctx->mount_opt, DISCARD_ASYNC);
454 btrfs_set_opt(ctx->mount_opt, NODISCARD);
455 } else {
456 btrfs_set_opt(ctx->mount_opt, DISCARD_SYNC);
457 btrfs_clear_opt(ctx->mount_opt, DISCARD_ASYNC);
458 }
459 break;
460 case Opt_discard_mode:
461 switch (result.uint_32) {
462 case Opt_discard_sync:
463 btrfs_clear_opt(ctx->mount_opt, DISCARD_ASYNC);
464 btrfs_set_opt(ctx->mount_opt, DISCARD_SYNC);
465 break;
466 case Opt_discard_async:
467 btrfs_clear_opt(ctx->mount_opt, DISCARD_SYNC);
468 btrfs_set_opt(ctx->mount_opt, DISCARD_ASYNC);
469 break;
470 default:
471 btrfs_err(NULL, "unrecognized discard mode value %s",
472 param->key);
473 return -EINVAL;
474 }
475 btrfs_clear_opt(ctx->mount_opt, NODISCARD);
476 break;
477 case Opt_space_cache:
478 if (result.negated) {
479 btrfs_set_opt(ctx->mount_opt, NOSPACECACHE);
480 btrfs_clear_opt(ctx->mount_opt, SPACE_CACHE);
481 btrfs_clear_opt(ctx->mount_opt, FREE_SPACE_TREE);
482 } else {
483 btrfs_clear_opt(ctx->mount_opt, FREE_SPACE_TREE);
484 btrfs_set_opt(ctx->mount_opt, SPACE_CACHE);
485 }
486 break;
487 case Opt_space_cache_version:
488 switch (result.uint_32) {
489 case Opt_space_cache_v1:
490 btrfs_set_opt(ctx->mount_opt, SPACE_CACHE);
491 btrfs_clear_opt(ctx->mount_opt, FREE_SPACE_TREE);
492 break;
493 case Opt_space_cache_v2:
494 btrfs_clear_opt(ctx->mount_opt, SPACE_CACHE);
495 btrfs_set_opt(ctx->mount_opt, FREE_SPACE_TREE);
496 break;
497 default:
498 btrfs_err(NULL, "unrecognized space_cache value %s",
499 param->key);
500 return -EINVAL;
501 }
502 break;
503 case Opt_rescan_uuid_tree:
504 btrfs_set_opt(ctx->mount_opt, RESCAN_UUID_TREE);
505 break;
506 case Opt_clear_cache:
507 btrfs_set_opt(ctx->mount_opt, CLEAR_CACHE);
508 break;
509 case Opt_user_subvol_rm_allowed:
510 btrfs_set_opt(ctx->mount_opt, USER_SUBVOL_RM_ALLOWED);
511 break;
512 case Opt_enospc_debug:
513 if (result.negated)
514 btrfs_clear_opt(ctx->mount_opt, ENOSPC_DEBUG);
515 else
516 btrfs_set_opt(ctx->mount_opt, ENOSPC_DEBUG);
517 break;
518 case Opt_defrag:
519 if (result.negated)
520 btrfs_clear_opt(ctx->mount_opt, AUTO_DEFRAG);
521 else
522 btrfs_set_opt(ctx->mount_opt, AUTO_DEFRAG);
523 break;
524 case Opt_usebackuproot:
525 btrfs_warn(NULL,
526 "'usebackuproot' is deprecated, use 'rescue=usebackuproot' instead");
527 btrfs_set_opt(ctx->mount_opt, USEBACKUPROOT);
528
529 /* If we're loading the backup roots we can't trust the space cache. */
530 btrfs_set_opt(ctx->mount_opt, CLEAR_CACHE);
531 break;
532 case Opt_skip_balance:
533 btrfs_set_opt(ctx->mount_opt, SKIP_BALANCE);
534 break;
535 case Opt_fatal_errors:
536 switch (result.uint_32) {
537 case Opt_fatal_errors_panic:
538 btrfs_set_opt(ctx->mount_opt, PANIC_ON_FATAL_ERROR);
539 break;
540 case Opt_fatal_errors_bug:
541 btrfs_clear_opt(ctx->mount_opt, PANIC_ON_FATAL_ERROR);
542 break;
543 default:
544 btrfs_err(NULL, "unrecognized fatal_errors value %s",
545 param->key);
546 return -EINVAL;
547 }
548 break;
549 case Opt_commit_interval:
550 ctx->commit_interval = result.uint_32;
551 if (ctx->commit_interval == 0)
552 ctx->commit_interval = BTRFS_DEFAULT_COMMIT_INTERVAL;
553 break;
554 case Opt_rescue:
555 switch (result.uint_32) {
556 case Opt_rescue_usebackuproot:
557 btrfs_set_opt(ctx->mount_opt, USEBACKUPROOT);
558 break;
559 case Opt_rescue_nologreplay:
560 btrfs_set_opt(ctx->mount_opt, NOLOGREPLAY);
561 break;
562 case Opt_rescue_ignorebadroots:
563 btrfs_set_opt(ctx->mount_opt, IGNOREBADROOTS);
564 break;
565 case Opt_rescue_ignoredatacsums:
566 btrfs_set_opt(ctx->mount_opt, IGNOREDATACSUMS);
567 break;
568 case Opt_rescue_parameter_all:
569 btrfs_set_opt(ctx->mount_opt, IGNOREDATACSUMS);
570 btrfs_set_opt(ctx->mount_opt, IGNOREBADROOTS);
571 btrfs_set_opt(ctx->mount_opt, NOLOGREPLAY);
572 break;
573 default:
574 btrfs_info(NULL, "unrecognized rescue option '%s'",
575 param->key);
576 return -EINVAL;
577 }
578 break;
579#ifdef CONFIG_BTRFS_DEBUG
580 case Opt_fragment:
581 switch (result.uint_32) {
582 case Opt_fragment_parameter_all:
583 btrfs_set_opt(ctx->mount_opt, FRAGMENT_DATA);
584 btrfs_set_opt(ctx->mount_opt, FRAGMENT_METADATA);
585 break;
586 case Opt_fragment_parameter_metadata:
587 btrfs_set_opt(ctx->mount_opt, FRAGMENT_METADATA);
588 break;
589 case Opt_fragment_parameter_data:
590 btrfs_set_opt(ctx->mount_opt, FRAGMENT_DATA);
591 break;
592 default:
593 btrfs_info(NULL, "unrecognized fragment option '%s'",
594 param->key);
595 return -EINVAL;
596 }
597 break;
598#endif
599#ifdef CONFIG_BTRFS_FS_REF_VERIFY
600 case Opt_ref_verify:
601 btrfs_set_opt(ctx->mount_opt, REF_VERIFY);
602 break;
603#endif
604 default:
605 btrfs_err(NULL, "unrecognized mount option '%s'", param->key);
606 return -EINVAL;
607 }
608
609 return 0;
610}
611
612/*
613 * Some options only have meaning at mount time and shouldn't persist across
614 * remounts, or be displayed. Clear these at the end of mount and remount code
615 * paths.
616 */
617static void btrfs_clear_oneshot_options(struct btrfs_fs_info *fs_info)
618{
619 btrfs_clear_opt(fs_info->mount_opt, USEBACKUPROOT);
620 btrfs_clear_opt(fs_info->mount_opt, CLEAR_CACHE);
621 btrfs_clear_opt(fs_info->mount_opt, NOSPACECACHE);
622}
623
624static bool check_ro_option(struct btrfs_fs_info *fs_info,
625 unsigned long mount_opt, unsigned long opt,
626 const char *opt_name)
627{
628 if (mount_opt & opt) {
629 btrfs_err(fs_info, "%s must be used with ro mount option",
630 opt_name);
631 return true;
632 }
633 return false;
634}
635
636bool btrfs_check_options(struct btrfs_fs_info *info, unsigned long *mount_opt,
637 unsigned long flags)
638{
639 bool ret = true;
640
641 if (!(flags & SB_RDONLY) &&
642 (check_ro_option(info, *mount_opt, BTRFS_MOUNT_NOLOGREPLAY, "nologreplay") ||
643 check_ro_option(info, *mount_opt, BTRFS_MOUNT_IGNOREBADROOTS, "ignorebadroots") ||
644 check_ro_option(info, *mount_opt, BTRFS_MOUNT_IGNOREDATACSUMS, "ignoredatacsums")))
645 ret = false;
646
647 if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE) &&
648 !btrfs_raw_test_opt(*mount_opt, FREE_SPACE_TREE) &&
649 !btrfs_raw_test_opt(*mount_opt, CLEAR_CACHE)) {
650 btrfs_err(info, "cannot disable free-space-tree");
651 ret = false;
652 }
653 if (btrfs_fs_compat_ro(info, BLOCK_GROUP_TREE) &&
654 !btrfs_raw_test_opt(*mount_opt, FREE_SPACE_TREE)) {
655 btrfs_err(info, "cannot disable free-space-tree with block-group-tree feature");
656 ret = false;
657 }
658
659 if (btrfs_check_mountopts_zoned(info, mount_opt))
660 ret = false;
661
662 if (!test_bit(BTRFS_FS_STATE_REMOUNTING, &info->fs_state)) {
663 if (btrfs_raw_test_opt(*mount_opt, SPACE_CACHE))
664 btrfs_info(info, "disk space caching is enabled");
665 if (btrfs_raw_test_opt(*mount_opt, FREE_SPACE_TREE))
666 btrfs_info(info, "using free-space-tree");
667 }
668
669 return ret;
670}
671
672/*
673 * This is subtle, we only call this during open_ctree(). We need to pre-load
674 * the mount options with the on-disk settings. Before the new mount API took
675 * effect we would do this on mount and remount. With the new mount API we'll
676 * only do this on the initial mount.
677 *
678 * This isn't a change in behavior, because we're using the current state of the
679 * file system to set the current mount options. If you mounted with special
680 * options to disable these features and then remounted we wouldn't revert the
681 * settings, because mounting without these features cleared the on-disk
682 * settings, so this being called on re-mount is not needed.
683 */
684void btrfs_set_free_space_cache_settings(struct btrfs_fs_info *fs_info)
685{
686 if (fs_info->sectorsize < PAGE_SIZE) {
687 btrfs_clear_opt(fs_info->mount_opt, SPACE_CACHE);
688 if (!btrfs_test_opt(fs_info, FREE_SPACE_TREE)) {
689 btrfs_info(fs_info,
690 "forcing free space tree for sector size %u with page size %lu",
691 fs_info->sectorsize, PAGE_SIZE);
692 btrfs_set_opt(fs_info->mount_opt, FREE_SPACE_TREE);
693 }
694 }
695
696 /*
697 * At this point our mount options are populated, so we only mess with
698 * these settings if we don't have any settings already.
699 */
700 if (btrfs_test_opt(fs_info, FREE_SPACE_TREE))
701 return;
702
703 if (btrfs_is_zoned(fs_info) &&
704 btrfs_free_space_cache_v1_active(fs_info)) {
705 btrfs_info(fs_info, "zoned: clearing existing space cache");
706 btrfs_set_super_cache_generation(fs_info->super_copy, 0);
707 return;
708 }
709
710 if (btrfs_test_opt(fs_info, SPACE_CACHE))
711 return;
712
713 if (btrfs_test_opt(fs_info, NOSPACECACHE))
714 return;
715
716 /*
717 * At this point we don't have explicit options set by the user, set
718 * them ourselves based on the state of the file system.
719 */
720 if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
721 btrfs_set_opt(fs_info->mount_opt, FREE_SPACE_TREE);
722 else if (btrfs_free_space_cache_v1_active(fs_info))
723 btrfs_set_opt(fs_info->mount_opt, SPACE_CACHE);
724}
725
726static void set_device_specific_options(struct btrfs_fs_info *fs_info)
727{
728 if (!btrfs_test_opt(fs_info, NOSSD) &&
729 !fs_info->fs_devices->rotating)
730 btrfs_set_opt(fs_info->mount_opt, SSD);
731
732 /*
733 * For devices supporting discard turn on discard=async automatically,
734 * unless it's already set or disabled. This could be turned off by
735 * nodiscard for the same mount.
736 *
737 * The zoned mode piggy backs on the discard functionality for
738 * resetting a zone. There is no reason to delay the zone reset as it is
739 * fast enough. So, do not enable async discard for zoned mode.
740 */
741 if (!(btrfs_test_opt(fs_info, DISCARD_SYNC) ||
742 btrfs_test_opt(fs_info, DISCARD_ASYNC) ||
743 btrfs_test_opt(fs_info, NODISCARD)) &&
744 fs_info->fs_devices->discardable &&
745 !btrfs_is_zoned(fs_info))
746 btrfs_set_opt(fs_info->mount_opt, DISCARD_ASYNC);
747}
748
749char *btrfs_get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
750 u64 subvol_objectid)
751{
752 struct btrfs_root *root = fs_info->tree_root;
753 struct btrfs_root *fs_root = NULL;
754 struct btrfs_root_ref *root_ref;
755 struct btrfs_inode_ref *inode_ref;
756 struct btrfs_key key;
757 struct btrfs_path *path = NULL;
758 char *name = NULL, *ptr;
759 u64 dirid;
760 int len;
761 int ret;
762
763 path = btrfs_alloc_path();
764 if (!path) {
765 ret = -ENOMEM;
766 goto err;
767 }
768
769 name = kmalloc(PATH_MAX, GFP_KERNEL);
770 if (!name) {
771 ret = -ENOMEM;
772 goto err;
773 }
774 ptr = name + PATH_MAX - 1;
775 ptr[0] = '\0';
776
777 /*
778 * Walk up the subvolume trees in the tree of tree roots by root
779 * backrefs until we hit the top-level subvolume.
780 */
781 while (subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
782 key.objectid = subvol_objectid;
783 key.type = BTRFS_ROOT_BACKREF_KEY;
784 key.offset = (u64)-1;
785
786 ret = btrfs_search_backwards(root, &key, path);
787 if (ret < 0) {
788 goto err;
789 } else if (ret > 0) {
790 ret = -ENOENT;
791 goto err;
792 }
793
794 subvol_objectid = key.offset;
795
796 root_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
797 struct btrfs_root_ref);
798 len = btrfs_root_ref_name_len(path->nodes[0], root_ref);
799 ptr -= len + 1;
800 if (ptr < name) {
801 ret = -ENAMETOOLONG;
802 goto err;
803 }
804 read_extent_buffer(path->nodes[0], ptr + 1,
805 (unsigned long)(root_ref + 1), len);
806 ptr[0] = '/';
807 dirid = btrfs_root_ref_dirid(path->nodes[0], root_ref);
808 btrfs_release_path(path);
809
810 fs_root = btrfs_get_fs_root(fs_info, subvol_objectid, true);
811 if (IS_ERR(fs_root)) {
812 ret = PTR_ERR(fs_root);
813 fs_root = NULL;
814 goto err;
815 }
816
817 /*
818 * Walk up the filesystem tree by inode refs until we hit the
819 * root directory.
820 */
821 while (dirid != BTRFS_FIRST_FREE_OBJECTID) {
822 key.objectid = dirid;
823 key.type = BTRFS_INODE_REF_KEY;
824 key.offset = (u64)-1;
825
826 ret = btrfs_search_backwards(fs_root, &key, path);
827 if (ret < 0) {
828 goto err;
829 } else if (ret > 0) {
830 ret = -ENOENT;
831 goto err;
832 }
833
834 dirid = key.offset;
835
836 inode_ref = btrfs_item_ptr(path->nodes[0],
837 path->slots[0],
838 struct btrfs_inode_ref);
839 len = btrfs_inode_ref_name_len(path->nodes[0],
840 inode_ref);
841 ptr -= len + 1;
842 if (ptr < name) {
843 ret = -ENAMETOOLONG;
844 goto err;
845 }
846 read_extent_buffer(path->nodes[0], ptr + 1,
847 (unsigned long)(inode_ref + 1), len);
848 ptr[0] = '/';
849 btrfs_release_path(path);
850 }
851 btrfs_put_root(fs_root);
852 fs_root = NULL;
853 }
854
855 btrfs_free_path(path);
856 if (ptr == name + PATH_MAX - 1) {
857 name[0] = '/';
858 name[1] = '\0';
859 } else {
860 memmove(name, ptr, name + PATH_MAX - ptr);
861 }
862 return name;
863
864err:
865 btrfs_put_root(fs_root);
866 btrfs_free_path(path);
867 kfree(name);
868 return ERR_PTR(ret);
869}
870
871static int get_default_subvol_objectid(struct btrfs_fs_info *fs_info, u64 *objectid)
872{
873 struct btrfs_root *root = fs_info->tree_root;
874 struct btrfs_dir_item *di;
875 struct btrfs_path *path;
876 struct btrfs_key location;
877 struct fscrypt_str name = FSTR_INIT("default", 7);
878 u64 dir_id;
879
880 path = btrfs_alloc_path();
881 if (!path)
882 return -ENOMEM;
883
884 /*
885 * Find the "default" dir item which points to the root item that we
886 * will mount by default if we haven't been given a specific subvolume
887 * to mount.
888 */
889 dir_id = btrfs_super_root_dir(fs_info->super_copy);
890 di = btrfs_lookup_dir_item(NULL, root, path, dir_id, &name, 0);
891 if (IS_ERR(di)) {
892 btrfs_free_path(path);
893 return PTR_ERR(di);
894 }
895 if (!di) {
896 /*
897 * Ok the default dir item isn't there. This is weird since
898 * it's always been there, but don't freak out, just try and
899 * mount the top-level subvolume.
900 */
901 btrfs_free_path(path);
902 *objectid = BTRFS_FS_TREE_OBJECTID;
903 return 0;
904 }
905
906 btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
907 btrfs_free_path(path);
908 *objectid = location.objectid;
909 return 0;
910}
911
912static int btrfs_fill_super(struct super_block *sb,
913 struct btrfs_fs_devices *fs_devices,
914 void *data)
915{
916 struct inode *inode;
917 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
918 int err;
919
920 sb->s_maxbytes = MAX_LFS_FILESIZE;
921 sb->s_magic = BTRFS_SUPER_MAGIC;
922 sb->s_op = &btrfs_super_ops;
923 sb->s_d_op = &btrfs_dentry_operations;
924 sb->s_export_op = &btrfs_export_ops;
925#ifdef CONFIG_FS_VERITY
926 sb->s_vop = &btrfs_verityops;
927#endif
928 sb->s_xattr = btrfs_xattr_handlers;
929 sb->s_time_gran = 1;
930 sb->s_iflags |= SB_I_CGROUPWB;
931
932 err = super_setup_bdi(sb);
933 if (err) {
934 btrfs_err(fs_info, "super_setup_bdi failed");
935 return err;
936 }
937
938 err = open_ctree(sb, fs_devices, (char *)data);
939 if (err) {
940 btrfs_err(fs_info, "open_ctree failed");
941 return err;
942 }
943
944 inode = btrfs_iget(sb, BTRFS_FIRST_FREE_OBJECTID, fs_info->fs_root);
945 if (IS_ERR(inode)) {
946 err = PTR_ERR(inode);
947 btrfs_handle_fs_error(fs_info, err, NULL);
948 goto fail_close;
949 }
950
951 sb->s_root = d_make_root(inode);
952 if (!sb->s_root) {
953 err = -ENOMEM;
954 goto fail_close;
955 }
956
957 sb->s_flags |= SB_ACTIVE;
958 return 0;
959
960fail_close:
961 close_ctree(fs_info);
962 return err;
963}
964
965int btrfs_sync_fs(struct super_block *sb, int wait)
966{
967 struct btrfs_trans_handle *trans;
968 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
969 struct btrfs_root *root = fs_info->tree_root;
970
971 trace_btrfs_sync_fs(fs_info, wait);
972
973 if (!wait) {
974 filemap_flush(fs_info->btree_inode->i_mapping);
975 return 0;
976 }
977
978 btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
979
980 trans = btrfs_attach_transaction_barrier(root);
981 if (IS_ERR(trans)) {
982 /* no transaction, don't bother */
983 if (PTR_ERR(trans) == -ENOENT) {
984 /*
985 * Exit unless we have some pending changes
986 * that need to go through commit
987 */
988 if (!test_bit(BTRFS_FS_NEED_TRANS_COMMIT,
989 &fs_info->flags))
990 return 0;
991 /*
992 * A non-blocking test if the fs is frozen. We must not
993 * start a new transaction here otherwise a deadlock
994 * happens. The pending operations are delayed to the
995 * next commit after thawing.
996 */
997 if (sb_start_write_trylock(sb))
998 sb_end_write(sb);
999 else
1000 return 0;
1001 trans = btrfs_start_transaction(root, 0);
1002 }
1003 if (IS_ERR(trans))
1004 return PTR_ERR(trans);
1005 }
1006 return btrfs_commit_transaction(trans);
1007}
1008
1009static void print_rescue_option(struct seq_file *seq, const char *s, bool *printed)
1010{
1011 seq_printf(seq, "%s%s", (*printed) ? ":" : ",rescue=", s);
1012 *printed = true;
1013}
1014
1015static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
1016{
1017 struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
1018 const char *compress_type;
1019 const char *subvol_name;
1020 bool printed = false;
1021
1022 if (btrfs_test_opt(info, DEGRADED))
1023 seq_puts(seq, ",degraded");
1024 if (btrfs_test_opt(info, NODATASUM))
1025 seq_puts(seq, ",nodatasum");
1026 if (btrfs_test_opt(info, NODATACOW))
1027 seq_puts(seq, ",nodatacow");
1028 if (btrfs_test_opt(info, NOBARRIER))
1029 seq_puts(seq, ",nobarrier");
1030 if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE)
1031 seq_printf(seq, ",max_inline=%llu", info->max_inline);
1032 if (info->thread_pool_size != min_t(unsigned long,
1033 num_online_cpus() + 2, 8))
1034 seq_printf(seq, ",thread_pool=%u", info->thread_pool_size);
1035 if (btrfs_test_opt(info, COMPRESS)) {
1036 compress_type = btrfs_compress_type2str(info->compress_type);
1037 if (btrfs_test_opt(info, FORCE_COMPRESS))
1038 seq_printf(seq, ",compress-force=%s", compress_type);
1039 else
1040 seq_printf(seq, ",compress=%s", compress_type);
1041 if (info->compress_level)
1042 seq_printf(seq, ":%d", info->compress_level);
1043 }
1044 if (btrfs_test_opt(info, NOSSD))
1045 seq_puts(seq, ",nossd");
1046 if (btrfs_test_opt(info, SSD_SPREAD))
1047 seq_puts(seq, ",ssd_spread");
1048 else if (btrfs_test_opt(info, SSD))
1049 seq_puts(seq, ",ssd");
1050 if (btrfs_test_opt(info, NOTREELOG))
1051 seq_puts(seq, ",notreelog");
1052 if (btrfs_test_opt(info, NOLOGREPLAY))
1053 print_rescue_option(seq, "nologreplay", &printed);
1054 if (btrfs_test_opt(info, USEBACKUPROOT))
1055 print_rescue_option(seq, "usebackuproot", &printed);
1056 if (btrfs_test_opt(info, IGNOREBADROOTS))
1057 print_rescue_option(seq, "ignorebadroots", &printed);
1058 if (btrfs_test_opt(info, IGNOREDATACSUMS))
1059 print_rescue_option(seq, "ignoredatacsums", &printed);
1060 if (btrfs_test_opt(info, FLUSHONCOMMIT))
1061 seq_puts(seq, ",flushoncommit");
1062 if (btrfs_test_opt(info, DISCARD_SYNC))
1063 seq_puts(seq, ",discard");
1064 if (btrfs_test_opt(info, DISCARD_ASYNC))
1065 seq_puts(seq, ",discard=async");
1066 if (!(info->sb->s_flags & SB_POSIXACL))
1067 seq_puts(seq, ",noacl");
1068 if (btrfs_free_space_cache_v1_active(info))
1069 seq_puts(seq, ",space_cache");
1070 else if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE))
1071 seq_puts(seq, ",space_cache=v2");
1072 else
1073 seq_puts(seq, ",nospace_cache");
1074 if (btrfs_test_opt(info, RESCAN_UUID_TREE))
1075 seq_puts(seq, ",rescan_uuid_tree");
1076 if (btrfs_test_opt(info, CLEAR_CACHE))
1077 seq_puts(seq, ",clear_cache");
1078 if (btrfs_test_opt(info, USER_SUBVOL_RM_ALLOWED))
1079 seq_puts(seq, ",user_subvol_rm_allowed");
1080 if (btrfs_test_opt(info, ENOSPC_DEBUG))
1081 seq_puts(seq, ",enospc_debug");
1082 if (btrfs_test_opt(info, AUTO_DEFRAG))
1083 seq_puts(seq, ",autodefrag");
1084 if (btrfs_test_opt(info, SKIP_BALANCE))
1085 seq_puts(seq, ",skip_balance");
1086 if (info->metadata_ratio)
1087 seq_printf(seq, ",metadata_ratio=%u", info->metadata_ratio);
1088 if (btrfs_test_opt(info, PANIC_ON_FATAL_ERROR))
1089 seq_puts(seq, ",fatal_errors=panic");
1090 if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL)
1091 seq_printf(seq, ",commit=%u", info->commit_interval);
1092#ifdef CONFIG_BTRFS_DEBUG
1093 if (btrfs_test_opt(info, FRAGMENT_DATA))
1094 seq_puts(seq, ",fragment=data");
1095 if (btrfs_test_opt(info, FRAGMENT_METADATA))
1096 seq_puts(seq, ",fragment=metadata");
1097#endif
1098 if (btrfs_test_opt(info, REF_VERIFY))
1099 seq_puts(seq, ",ref_verify");
1100 seq_printf(seq, ",subvolid=%llu",
1101 BTRFS_I(d_inode(dentry))->root->root_key.objectid);
1102 subvol_name = btrfs_get_subvol_name_from_objectid(info,
1103 BTRFS_I(d_inode(dentry))->root->root_key.objectid);
1104 if (!IS_ERR(subvol_name)) {
1105 seq_puts(seq, ",subvol=");
1106 seq_escape(seq, subvol_name, " \t\n\\");
1107 kfree(subvol_name);
1108 }
1109 return 0;
1110}
1111
1112/*
1113 * subvolumes are identified by ino 256
1114 */
1115static inline int is_subvolume_inode(struct inode *inode)
1116{
1117 if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
1118 return 1;
1119 return 0;
1120}
1121
1122static struct dentry *mount_subvol(const char *subvol_name, u64 subvol_objectid,
1123 struct vfsmount *mnt)
1124{
1125 struct dentry *root;
1126 int ret;
1127
1128 if (!subvol_name) {
1129 if (!subvol_objectid) {
1130 ret = get_default_subvol_objectid(btrfs_sb(mnt->mnt_sb),
1131 &subvol_objectid);
1132 if (ret) {
1133 root = ERR_PTR(ret);
1134 goto out;
1135 }
1136 }
1137 subvol_name = btrfs_get_subvol_name_from_objectid(
1138 btrfs_sb(mnt->mnt_sb), subvol_objectid);
1139 if (IS_ERR(subvol_name)) {
1140 root = ERR_CAST(subvol_name);
1141 subvol_name = NULL;
1142 goto out;
1143 }
1144
1145 }
1146
1147 root = mount_subtree(mnt, subvol_name);
1148 /* mount_subtree() drops our reference on the vfsmount. */
1149 mnt = NULL;
1150
1151 if (!IS_ERR(root)) {
1152 struct super_block *s = root->d_sb;
1153 struct btrfs_fs_info *fs_info = btrfs_sb(s);
1154 struct inode *root_inode = d_inode(root);
1155 u64 root_objectid = BTRFS_I(root_inode)->root->root_key.objectid;
1156
1157 ret = 0;
1158 if (!is_subvolume_inode(root_inode)) {
1159 btrfs_err(fs_info, "'%s' is not a valid subvolume",
1160 subvol_name);
1161 ret = -EINVAL;
1162 }
1163 if (subvol_objectid && root_objectid != subvol_objectid) {
1164 /*
1165 * This will also catch a race condition where a
1166 * subvolume which was passed by ID is renamed and
1167 * another subvolume is renamed over the old location.
1168 */
1169 btrfs_err(fs_info,
1170 "subvol '%s' does not match subvolid %llu",
1171 subvol_name, subvol_objectid);
1172 ret = -EINVAL;
1173 }
1174 if (ret) {
1175 dput(root);
1176 root = ERR_PTR(ret);
1177 deactivate_locked_super(s);
1178 }
1179 }
1180
1181out:
1182 mntput(mnt);
1183 kfree(subvol_name);
1184 return root;
1185}
1186
1187static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
1188 u32 new_pool_size, u32 old_pool_size)
1189{
1190 if (new_pool_size == old_pool_size)
1191 return;
1192
1193 fs_info->thread_pool_size = new_pool_size;
1194
1195 btrfs_info(fs_info, "resize thread pool %d -> %d",
1196 old_pool_size, new_pool_size);
1197
1198 btrfs_workqueue_set_max(fs_info->workers, new_pool_size);
1199 btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size);
1200 btrfs_workqueue_set_max(fs_info->caching_workers, new_pool_size);
1201 workqueue_set_max_active(fs_info->endio_workers, new_pool_size);
1202 workqueue_set_max_active(fs_info->endio_meta_workers, new_pool_size);
1203 btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size);
1204 btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
1205 btrfs_workqueue_set_max(fs_info->delayed_workers, new_pool_size);
1206}
1207
1208static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info,
1209 unsigned long old_opts, int flags)
1210{
1211 if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1212 (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1213 (flags & SB_RDONLY))) {
1214 /* wait for any defraggers to finish */
1215 wait_event(fs_info->transaction_wait,
1216 (atomic_read(&fs_info->defrag_running) == 0));
1217 if (flags & SB_RDONLY)
1218 sync_filesystem(fs_info->sb);
1219 }
1220}
1221
1222static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
1223 unsigned long old_opts)
1224{
1225 const bool cache_opt = btrfs_test_opt(fs_info, SPACE_CACHE);
1226
1227 /*
1228 * We need to cleanup all defragable inodes if the autodefragment is
1229 * close or the filesystem is read only.
1230 */
1231 if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1232 (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) || sb_rdonly(fs_info->sb))) {
1233 btrfs_cleanup_defrag_inodes(fs_info);
1234 }
1235
1236 /* If we toggled discard async */
1237 if (!btrfs_raw_test_opt(old_opts, DISCARD_ASYNC) &&
1238 btrfs_test_opt(fs_info, DISCARD_ASYNC))
1239 btrfs_discard_resume(fs_info);
1240 else if (btrfs_raw_test_opt(old_opts, DISCARD_ASYNC) &&
1241 !btrfs_test_opt(fs_info, DISCARD_ASYNC))
1242 btrfs_discard_cleanup(fs_info);
1243
1244 /* If we toggled space cache */
1245 if (cache_opt != btrfs_free_space_cache_v1_active(fs_info))
1246 btrfs_set_free_space_cache_v1_active(fs_info, cache_opt);
1247}
1248
1249static int btrfs_remount_rw(struct btrfs_fs_info *fs_info)
1250{
1251 int ret;
1252
1253 if (BTRFS_FS_ERROR(fs_info)) {
1254 btrfs_err(fs_info,
1255 "remounting read-write after error is not allowed");
1256 return -EINVAL;
1257 }
1258
1259 if (fs_info->fs_devices->rw_devices == 0)
1260 return -EACCES;
1261
1262 if (!btrfs_check_rw_degradable(fs_info, NULL)) {
1263 btrfs_warn(fs_info,
1264 "too many missing devices, writable remount is not allowed");
1265 return -EACCES;
1266 }
1267
1268 if (btrfs_super_log_root(fs_info->super_copy) != 0) {
1269 btrfs_warn(fs_info,
1270 "mount required to replay tree-log, cannot remount read-write");
1271 return -EINVAL;
1272 }
1273
1274 /*
1275 * NOTE: when remounting with a change that does writes, don't put it
1276 * anywhere above this point, as we are not sure to be safe to write
1277 * until we pass the above checks.
1278 */
1279 ret = btrfs_start_pre_rw_mount(fs_info);
1280 if (ret)
1281 return ret;
1282
1283 btrfs_clear_sb_rdonly(fs_info->sb);
1284
1285 set_bit(BTRFS_FS_OPEN, &fs_info->flags);
1286
1287 /*
1288 * If we've gone from readonly -> read-write, we need to get our
1289 * sync/async discard lists in the right state.
1290 */
1291 btrfs_discard_resume(fs_info);
1292
1293 return 0;
1294}
1295
1296static int btrfs_remount_ro(struct btrfs_fs_info *fs_info)
1297{
1298 /*
1299 * This also happens on 'umount -rf' or on shutdown, when the
1300 * filesystem is busy.
1301 */
1302 cancel_work_sync(&fs_info->async_reclaim_work);
1303 cancel_work_sync(&fs_info->async_data_reclaim_work);
1304
1305 btrfs_discard_cleanup(fs_info);
1306
1307 /* Wait for the uuid_scan task to finish */
1308 down(&fs_info->uuid_tree_rescan_sem);
1309 /* Avoid complains from lockdep et al. */
1310 up(&fs_info->uuid_tree_rescan_sem);
1311
1312 btrfs_set_sb_rdonly(fs_info->sb);
1313
1314 /*
1315 * Setting SB_RDONLY will put the cleaner thread to sleep at the next
1316 * loop if it's already active. If it's already asleep, we'll leave
1317 * unused block groups on disk until we're mounted read-write again
1318 * unless we clean them up here.
1319 */
1320 btrfs_delete_unused_bgs(fs_info);
1321
1322 /*
1323 * The cleaner task could be already running before we set the flag
1324 * BTRFS_FS_STATE_RO (and SB_RDONLY in the superblock). We must make
1325 * sure that after we finish the remount, i.e. after we call
1326 * btrfs_commit_super(), the cleaner can no longer start a transaction
1327 * - either because it was dropping a dead root, running delayed iputs
1328 * or deleting an unused block group (the cleaner picked a block
1329 * group from the list of unused block groups before we were able to
1330 * in the previous call to btrfs_delete_unused_bgs()).
1331 */
1332 wait_on_bit(&fs_info->flags, BTRFS_FS_CLEANER_RUNNING, TASK_UNINTERRUPTIBLE);
1333
1334 /*
1335 * We've set the superblock to RO mode, so we might have made the
1336 * cleaner task sleep without running all pending delayed iputs. Go
1337 * through all the delayed iputs here, so that if an unmount happens
1338 * without remounting RW we don't end up at finishing close_ctree()
1339 * with a non-empty list of delayed iputs.
1340 */
1341 btrfs_run_delayed_iputs(fs_info);
1342
1343 btrfs_dev_replace_suspend_for_unmount(fs_info);
1344 btrfs_scrub_cancel(fs_info);
1345 btrfs_pause_balance(fs_info);
1346
1347 /*
1348 * Pause the qgroup rescan worker if it is running. We don't want it to
1349 * be still running after we are in RO mode, as after that, by the time
1350 * we unmount, it might have left a transaction open, so we would leak
1351 * the transaction and/or crash.
1352 */
1353 btrfs_qgroup_wait_for_completion(fs_info, false);
1354
1355 return btrfs_commit_super(fs_info);
1356}
1357
1358static void btrfs_ctx_to_info(struct btrfs_fs_info *fs_info, struct btrfs_fs_context *ctx)
1359{
1360 fs_info->max_inline = ctx->max_inline;
1361 fs_info->commit_interval = ctx->commit_interval;
1362 fs_info->metadata_ratio = ctx->metadata_ratio;
1363 fs_info->thread_pool_size = ctx->thread_pool_size;
1364 fs_info->mount_opt = ctx->mount_opt;
1365 fs_info->compress_type = ctx->compress_type;
1366 fs_info->compress_level = ctx->compress_level;
1367}
1368
1369static void btrfs_info_to_ctx(struct btrfs_fs_info *fs_info, struct btrfs_fs_context *ctx)
1370{
1371 ctx->max_inline = fs_info->max_inline;
1372 ctx->commit_interval = fs_info->commit_interval;
1373 ctx->metadata_ratio = fs_info->metadata_ratio;
1374 ctx->thread_pool_size = fs_info->thread_pool_size;
1375 ctx->mount_opt = fs_info->mount_opt;
1376 ctx->compress_type = fs_info->compress_type;
1377 ctx->compress_level = fs_info->compress_level;
1378}
1379
1380#define btrfs_info_if_set(fs_info, old_ctx, opt, fmt, args...) \
1381do { \
1382 if ((!old_ctx || !btrfs_raw_test_opt(old_ctx->mount_opt, opt)) && \
1383 btrfs_raw_test_opt(fs_info->mount_opt, opt)) \
1384 btrfs_info(fs_info, fmt, ##args); \
1385} while (0)
1386
1387#define btrfs_info_if_unset(fs_info, old_ctx, opt, fmt, args...) \
1388do { \
1389 if ((old_ctx && btrfs_raw_test_opt(old_ctx->mount_opt, opt)) && \
1390 !btrfs_raw_test_opt(fs_info->mount_opt, opt)) \
1391 btrfs_info(fs_info, fmt, ##args); \
1392} while (0)
1393
1394static void btrfs_emit_options(struct btrfs_fs_info *info,
1395 struct btrfs_fs_context *old)
1396{
1397 btrfs_info_if_set(info, old, NODATASUM, "setting nodatasum");
1398 btrfs_info_if_set(info, old, DEGRADED, "allowing degraded mounts");
1399 btrfs_info_if_set(info, old, NODATASUM, "setting nodatasum");
1400 btrfs_info_if_set(info, old, SSD, "enabling ssd optimizations");
1401 btrfs_info_if_set(info, old, SSD_SPREAD, "using spread ssd allocation scheme");
1402 btrfs_info_if_set(info, old, NOBARRIER, "turning off barriers");
1403 btrfs_info_if_set(info, old, NOTREELOG, "disabling tree log");
1404 btrfs_info_if_set(info, old, NOLOGREPLAY, "disabling log replay at mount time");
1405 btrfs_info_if_set(info, old, FLUSHONCOMMIT, "turning on flush-on-commit");
1406 btrfs_info_if_set(info, old, DISCARD_SYNC, "turning on sync discard");
1407 btrfs_info_if_set(info, old, DISCARD_ASYNC, "turning on async discard");
1408 btrfs_info_if_set(info, old, FREE_SPACE_TREE, "enabling free space tree");
1409 btrfs_info_if_set(info, old, SPACE_CACHE, "enabling disk space caching");
1410 btrfs_info_if_set(info, old, CLEAR_CACHE, "force clearing of disk cache");
1411 btrfs_info_if_set(info, old, AUTO_DEFRAG, "enabling auto defrag");
1412 btrfs_info_if_set(info, old, FRAGMENT_DATA, "fragmenting data");
1413 btrfs_info_if_set(info, old, FRAGMENT_METADATA, "fragmenting metadata");
1414 btrfs_info_if_set(info, old, REF_VERIFY, "doing ref verification");
1415 btrfs_info_if_set(info, old, USEBACKUPROOT, "trying to use backup root at mount time");
1416 btrfs_info_if_set(info, old, IGNOREBADROOTS, "ignoring bad roots");
1417 btrfs_info_if_set(info, old, IGNOREDATACSUMS, "ignoring data csums");
1418
1419 btrfs_info_if_unset(info, old, NODATACOW, "setting datacow");
1420 btrfs_info_if_unset(info, old, SSD, "not using ssd optimizations");
1421 btrfs_info_if_unset(info, old, SSD_SPREAD, "not using spread ssd allocation scheme");
1422 btrfs_info_if_unset(info, old, NOBARRIER, "turning off barriers");
1423 btrfs_info_if_unset(info, old, NOTREELOG, "enabling tree log");
1424 btrfs_info_if_unset(info, old, SPACE_CACHE, "disabling disk space caching");
1425 btrfs_info_if_unset(info, old, FREE_SPACE_TREE, "disabling free space tree");
1426 btrfs_info_if_unset(info, old, AUTO_DEFRAG, "disabling auto defrag");
1427 btrfs_info_if_unset(info, old, COMPRESS, "use no compression");
1428
1429 /* Did the compression settings change? */
1430 if (btrfs_test_opt(info, COMPRESS) &&
1431 (!old ||
1432 old->compress_type != info->compress_type ||
1433 old->compress_level != info->compress_level ||
1434 (!btrfs_raw_test_opt(old->mount_opt, FORCE_COMPRESS) &&
1435 btrfs_raw_test_opt(info->mount_opt, FORCE_COMPRESS)))) {
1436 const char *compress_type = btrfs_compress_type2str(info->compress_type);
1437
1438 btrfs_info(info, "%s %s compression, level %d",
1439 btrfs_test_opt(info, FORCE_COMPRESS) ? "force" : "use",
1440 compress_type, info->compress_level);
1441 }
1442
1443 if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE)
1444 btrfs_info(info, "max_inline set to %llu", info->max_inline);
1445}
1446
1447static int btrfs_reconfigure(struct fs_context *fc)
1448{
1449 struct super_block *sb = fc->root->d_sb;
1450 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1451 struct btrfs_fs_context *ctx = fc->fs_private;
1452 struct btrfs_fs_context old_ctx;
1453 int ret = 0;
1454 bool mount_reconfigure = (fc->s_fs_info != NULL);
1455
1456 btrfs_info_to_ctx(fs_info, &old_ctx);
1457
1458 /*
1459 * This is our "bind mount" trick, we don't want to allow the user to do
1460 * anything other than mount a different ro/rw and a different subvol,
1461 * all of the mount options should be maintained.
1462 */
1463 if (mount_reconfigure)
1464 ctx->mount_opt = old_ctx.mount_opt;
1465
1466 sync_filesystem(sb);
1467 set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1468
1469 if (!mount_reconfigure &&
1470 !btrfs_check_options(fs_info, &ctx->mount_opt, fc->sb_flags))
1471 return -EINVAL;
1472
1473 ret = btrfs_check_features(fs_info, !(fc->sb_flags & SB_RDONLY));
1474 if (ret < 0)
1475 return ret;
1476
1477 btrfs_ctx_to_info(fs_info, ctx);
1478 btrfs_remount_begin(fs_info, old_ctx.mount_opt, fc->sb_flags);
1479 btrfs_resize_thread_pool(fs_info, fs_info->thread_pool_size,
1480 old_ctx.thread_pool_size);
1481
1482 if ((bool)btrfs_test_opt(fs_info, FREE_SPACE_TREE) !=
1483 (bool)btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE) &&
1484 (!sb_rdonly(sb) || (fc->sb_flags & SB_RDONLY))) {
1485 btrfs_warn(fs_info,
1486 "remount supports changing free space tree only from RO to RW");
1487 /* Make sure free space cache options match the state on disk. */
1488 if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE)) {
1489 btrfs_set_opt(fs_info->mount_opt, FREE_SPACE_TREE);
1490 btrfs_clear_opt(fs_info->mount_opt, SPACE_CACHE);
1491 }
1492 if (btrfs_free_space_cache_v1_active(fs_info)) {
1493 btrfs_clear_opt(fs_info->mount_opt, FREE_SPACE_TREE);
1494 btrfs_set_opt(fs_info->mount_opt, SPACE_CACHE);
1495 }
1496 }
1497
1498 ret = 0;
1499 if (!sb_rdonly(sb) && (fc->sb_flags & SB_RDONLY))
1500 ret = btrfs_remount_ro(fs_info);
1501 else if (sb_rdonly(sb) && !(fc->sb_flags & SB_RDONLY))
1502 ret = btrfs_remount_rw(fs_info);
1503 if (ret)
1504 goto restore;
1505
1506 /*
1507 * If we set the mask during the parameter parsing VFS would reject the
1508 * remount. Here we can set the mask and the value will be updated
1509 * appropriately.
1510 */
1511 if ((fc->sb_flags & SB_POSIXACL) != (sb->s_flags & SB_POSIXACL))
1512 fc->sb_flags_mask |= SB_POSIXACL;
1513
1514 btrfs_emit_options(fs_info, &old_ctx);
1515 wake_up_process(fs_info->transaction_kthread);
1516 btrfs_remount_cleanup(fs_info, old_ctx.mount_opt);
1517 btrfs_clear_oneshot_options(fs_info);
1518 clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1519
1520 return 0;
1521restore:
1522 btrfs_ctx_to_info(fs_info, &old_ctx);
1523 btrfs_remount_cleanup(fs_info, old_ctx.mount_opt);
1524 clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1525 return ret;
1526}
1527
1528/* Used to sort the devices by max_avail(descending sort) */
1529static int btrfs_cmp_device_free_bytes(const void *a, const void *b)
1530{
1531 const struct btrfs_device_info *dev_info1 = a;
1532 const struct btrfs_device_info *dev_info2 = b;
1533
1534 if (dev_info1->max_avail > dev_info2->max_avail)
1535 return -1;
1536 else if (dev_info1->max_avail < dev_info2->max_avail)
1537 return 1;
1538 return 0;
1539}
1540
1541/*
1542 * sort the devices by max_avail, in which max free extent size of each device
1543 * is stored.(Descending Sort)
1544 */
1545static inline void btrfs_descending_sort_devices(
1546 struct btrfs_device_info *devices,
1547 size_t nr_devices)
1548{
1549 sort(devices, nr_devices, sizeof(struct btrfs_device_info),
1550 btrfs_cmp_device_free_bytes, NULL);
1551}
1552
1553/*
1554 * The helper to calc the free space on the devices that can be used to store
1555 * file data.
1556 */
1557static inline int btrfs_calc_avail_data_space(struct btrfs_fs_info *fs_info,
1558 u64 *free_bytes)
1559{
1560 struct btrfs_device_info *devices_info;
1561 struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
1562 struct btrfs_device *device;
1563 u64 type;
1564 u64 avail_space;
1565 u64 min_stripe_size;
1566 int num_stripes = 1;
1567 int i = 0, nr_devices;
1568 const struct btrfs_raid_attr *rattr;
1569
1570 /*
1571 * We aren't under the device list lock, so this is racy-ish, but good
1572 * enough for our purposes.
1573 */
1574 nr_devices = fs_info->fs_devices->open_devices;
1575 if (!nr_devices) {
1576 smp_mb();
1577 nr_devices = fs_info->fs_devices->open_devices;
1578 ASSERT(nr_devices);
1579 if (!nr_devices) {
1580 *free_bytes = 0;
1581 return 0;
1582 }
1583 }
1584
1585 devices_info = kmalloc_array(nr_devices, sizeof(*devices_info),
1586 GFP_KERNEL);
1587 if (!devices_info)
1588 return -ENOMEM;
1589
1590 /* calc min stripe number for data space allocation */
1591 type = btrfs_data_alloc_profile(fs_info);
1592 rattr = &btrfs_raid_array[btrfs_bg_flags_to_raid_index(type)];
1593
1594 if (type & BTRFS_BLOCK_GROUP_RAID0)
1595 num_stripes = nr_devices;
1596 else if (type & BTRFS_BLOCK_GROUP_RAID1_MASK)
1597 num_stripes = rattr->ncopies;
1598 else if (type & BTRFS_BLOCK_GROUP_RAID10)
1599 num_stripes = 4;
1600
1601 /* Adjust for more than 1 stripe per device */
1602 min_stripe_size = rattr->dev_stripes * BTRFS_STRIPE_LEN;
1603
1604 rcu_read_lock();
1605 list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
1606 if (!test_bit(BTRFS_DEV_STATE_IN_FS_METADATA,
1607 &device->dev_state) ||
1608 !device->bdev ||
1609 test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state))
1610 continue;
1611
1612 if (i >= nr_devices)
1613 break;
1614
1615 avail_space = device->total_bytes - device->bytes_used;
1616
1617 /* align with stripe_len */
1618 avail_space = rounddown(avail_space, BTRFS_STRIPE_LEN);
1619
1620 /*
1621 * Ensure we have at least min_stripe_size on top of the
1622 * reserved space on the device.
1623 */
1624 if (avail_space <= BTRFS_DEVICE_RANGE_RESERVED + min_stripe_size)
1625 continue;
1626
1627 avail_space -= BTRFS_DEVICE_RANGE_RESERVED;
1628
1629 devices_info[i].dev = device;
1630 devices_info[i].max_avail = avail_space;
1631
1632 i++;
1633 }
1634 rcu_read_unlock();
1635
1636 nr_devices = i;
1637
1638 btrfs_descending_sort_devices(devices_info, nr_devices);
1639
1640 i = nr_devices - 1;
1641 avail_space = 0;
1642 while (nr_devices >= rattr->devs_min) {
1643 num_stripes = min(num_stripes, nr_devices);
1644
1645 if (devices_info[i].max_avail >= min_stripe_size) {
1646 int j;
1647 u64 alloc_size;
1648
1649 avail_space += devices_info[i].max_avail * num_stripes;
1650 alloc_size = devices_info[i].max_avail;
1651 for (j = i + 1 - num_stripes; j <= i; j++)
1652 devices_info[j].max_avail -= alloc_size;
1653 }
1654 i--;
1655 nr_devices--;
1656 }
1657
1658 kfree(devices_info);
1659 *free_bytes = avail_space;
1660 return 0;
1661}
1662
1663/*
1664 * Calculate numbers for 'df', pessimistic in case of mixed raid profiles.
1665 *
1666 * If there's a redundant raid level at DATA block groups, use the respective
1667 * multiplier to scale the sizes.
1668 *
1669 * Unused device space usage is based on simulating the chunk allocator
1670 * algorithm that respects the device sizes and order of allocations. This is
1671 * a close approximation of the actual use but there are other factors that may
1672 * change the result (like a new metadata chunk).
1673 *
1674 * If metadata is exhausted, f_bavail will be 0.
1675 */
1676static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
1677{
1678 struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
1679 struct btrfs_super_block *disk_super = fs_info->super_copy;
1680 struct btrfs_space_info *found;
1681 u64 total_used = 0;
1682 u64 total_free_data = 0;
1683 u64 total_free_meta = 0;
1684 u32 bits = fs_info->sectorsize_bits;
1685 __be32 *fsid = (__be32 *)fs_info->fs_devices->fsid;
1686 unsigned factor = 1;
1687 struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
1688 int ret;
1689 u64 thresh = 0;
1690 int mixed = 0;
1691
1692 list_for_each_entry(found, &fs_info->space_info, list) {
1693 if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
1694 int i;
1695
1696 total_free_data += found->disk_total - found->disk_used;
1697 total_free_data -=
1698 btrfs_account_ro_block_groups_free_space(found);
1699
1700 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
1701 if (!list_empty(&found->block_groups[i]))
1702 factor = btrfs_bg_type_to_factor(
1703 btrfs_raid_array[i].bg_flag);
1704 }
1705 }
1706
1707 /*
1708 * Metadata in mixed block group profiles are accounted in data
1709 */
1710 if (!mixed && found->flags & BTRFS_BLOCK_GROUP_METADATA) {
1711 if (found->flags & BTRFS_BLOCK_GROUP_DATA)
1712 mixed = 1;
1713 else
1714 total_free_meta += found->disk_total -
1715 found->disk_used;
1716 }
1717
1718 total_used += found->disk_used;
1719 }
1720
1721 buf->f_blocks = div_u64(btrfs_super_total_bytes(disk_super), factor);
1722 buf->f_blocks >>= bits;
1723 buf->f_bfree = buf->f_blocks - (div_u64(total_used, factor) >> bits);
1724
1725 /* Account global block reserve as used, it's in logical size already */
1726 spin_lock(&block_rsv->lock);
1727 /* Mixed block groups accounting is not byte-accurate, avoid overflow */
1728 if (buf->f_bfree >= block_rsv->size >> bits)
1729 buf->f_bfree -= block_rsv->size >> bits;
1730 else
1731 buf->f_bfree = 0;
1732 spin_unlock(&block_rsv->lock);
1733
1734 buf->f_bavail = div_u64(total_free_data, factor);
1735 ret = btrfs_calc_avail_data_space(fs_info, &total_free_data);
1736 if (ret)
1737 return ret;
1738 buf->f_bavail += div_u64(total_free_data, factor);
1739 buf->f_bavail = buf->f_bavail >> bits;
1740
1741 /*
1742 * We calculate the remaining metadata space minus global reserve. If
1743 * this is (supposedly) smaller than zero, there's no space. But this
1744 * does not hold in practice, the exhausted state happens where's still
1745 * some positive delta. So we apply some guesswork and compare the
1746 * delta to a 4M threshold. (Practically observed delta was ~2M.)
1747 *
1748 * We probably cannot calculate the exact threshold value because this
1749 * depends on the internal reservations requested by various
1750 * operations, so some operations that consume a few metadata will
1751 * succeed even if the Avail is zero. But this is better than the other
1752 * way around.
1753 */
1754 thresh = SZ_4M;
1755
1756 /*
1757 * We only want to claim there's no available space if we can no longer
1758 * allocate chunks for our metadata profile and our global reserve will
1759 * not fit in the free metadata space. If we aren't ->full then we
1760 * still can allocate chunks and thus are fine using the currently
1761 * calculated f_bavail.
1762 */
1763 if (!mixed && block_rsv->space_info->full &&
1764 (total_free_meta < thresh || total_free_meta - thresh < block_rsv->size))
1765 buf->f_bavail = 0;
1766
1767 buf->f_type = BTRFS_SUPER_MAGIC;
1768 buf->f_bsize = fs_info->sectorsize;
1769 buf->f_namelen = BTRFS_NAME_LEN;
1770
1771 /* We treat it as constant endianness (it doesn't matter _which_)
1772 because we want the fsid to come out the same whether mounted
1773 on a big-endian or little-endian host */
1774 buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
1775 buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
1776 /* Mask in the root object ID too, to disambiguate subvols */
1777 buf->f_fsid.val[0] ^=
1778 BTRFS_I(d_inode(dentry))->root->root_key.objectid >> 32;
1779 buf->f_fsid.val[1] ^=
1780 BTRFS_I(d_inode(dentry))->root->root_key.objectid;
1781
1782 return 0;
1783}
1784
1785static int btrfs_fc_test_super(struct super_block *sb, struct fs_context *fc)
1786{
1787 struct btrfs_fs_info *p = fc->s_fs_info;
1788 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1789
1790 return fs_info->fs_devices == p->fs_devices;
1791}
1792
1793static int btrfs_get_tree_super(struct fs_context *fc)
1794{
1795 struct btrfs_fs_info *fs_info = fc->s_fs_info;
1796 struct btrfs_fs_context *ctx = fc->fs_private;
1797 struct btrfs_fs_devices *fs_devices = NULL;
1798 struct block_device *bdev;
1799 struct btrfs_device *device;
1800 struct super_block *sb;
1801 blk_mode_t mode = btrfs_open_mode(fc);
1802 int ret;
1803
1804 btrfs_ctx_to_info(fs_info, ctx);
1805 mutex_lock(&uuid_mutex);
1806
1807 /*
1808 * With 'true' passed to btrfs_scan_one_device() (mount time) we expect
1809 * either a valid device or an error.
1810 */
1811 device = btrfs_scan_one_device(fc->source, mode, true);
1812 ASSERT(device != NULL);
1813 if (IS_ERR(device)) {
1814 mutex_unlock(&uuid_mutex);
1815 return PTR_ERR(device);
1816 }
1817
1818 fs_devices = device->fs_devices;
1819 fs_info->fs_devices = fs_devices;
1820
1821 ret = btrfs_open_devices(fs_devices, mode, &btrfs_fs_type);
1822 mutex_unlock(&uuid_mutex);
1823 if (ret)
1824 return ret;
1825
1826 if (!(fc->sb_flags & SB_RDONLY) && fs_devices->rw_devices == 0) {
1827 ret = -EACCES;
1828 goto error;
1829 }
1830
1831 bdev = fs_devices->latest_dev->bdev;
1832
1833 /*
1834 * From now on the error handling is not straightforward.
1835 *
1836 * If successful, this will transfer the fs_info into the super block,
1837 * and fc->s_fs_info will be NULL. However if there's an existing
1838 * super, we'll still have fc->s_fs_info populated. If we error
1839 * completely out it'll be cleaned up when we drop the fs_context,
1840 * otherwise it's tied to the lifetime of the super_block.
1841 */
1842 sb = sget_fc(fc, btrfs_fc_test_super, set_anon_super_fc);
1843 if (IS_ERR(sb)) {
1844 ret = PTR_ERR(sb);
1845 goto error;
1846 }
1847
1848 set_device_specific_options(fs_info);
1849
1850 if (sb->s_root) {
1851 btrfs_close_devices(fs_devices);
1852 if ((fc->sb_flags ^ sb->s_flags) & SB_RDONLY)
1853 ret = -EBUSY;
1854 } else {
1855 snprintf(sb->s_id, sizeof(sb->s_id), "%pg", bdev);
1856 shrinker_debugfs_rename(sb->s_shrink, "sb-btrfs:%s", sb->s_id);
1857 btrfs_sb(sb)->bdev_holder = &btrfs_fs_type;
1858 ret = btrfs_fill_super(sb, fs_devices, NULL);
1859 }
1860
1861 if (ret) {
1862 deactivate_locked_super(sb);
1863 return ret;
1864 }
1865
1866 btrfs_clear_oneshot_options(fs_info);
1867
1868 fc->root = dget(sb->s_root);
1869 return 0;
1870
1871error:
1872 btrfs_close_devices(fs_devices);
1873 return ret;
1874}
1875
1876/*
1877 * Ever since commit 0723a0473fb4 ("btrfs: allow mounting btrfs subvolumes
1878 * with different ro/rw options") the following works:
1879 *
1880 * (i) mount /dev/sda3 -o subvol=foo,ro /mnt/foo
1881 * (ii) mount /dev/sda3 -o subvol=bar,rw /mnt/bar
1882 *
1883 * which looks nice and innocent but is actually pretty intricate and deserves
1884 * a long comment.
1885 *
1886 * On another filesystem a subvolume mount is close to something like:
1887 *
1888 * (iii) # create rw superblock + initial mount
1889 * mount -t xfs /dev/sdb /opt/
1890 *
1891 * # create ro bind mount
1892 * mount --bind -o ro /opt/foo /mnt/foo
1893 *
1894 * # unmount initial mount
1895 * umount /opt
1896 *
1897 * Of course, there's some special subvolume sauce and there's the fact that the
1898 * sb->s_root dentry is really swapped after mount_subtree(). But conceptually
1899 * it's very close and will help us understand the issue.
1900 *
1901 * The old mount API didn't cleanly distinguish between a mount being made ro
1902 * and a superblock being made ro. The only way to change the ro state of
1903 * either object was by passing ms_rdonly. If a new mount was created via
1904 * mount(2) such as:
1905 *
1906 * mount("/dev/sdb", "/mnt", "xfs", ms_rdonly, null);
1907 *
1908 * the MS_RDONLY flag being specified had two effects:
1909 *
1910 * (1) MNT_READONLY was raised -> the resulting mount got
1911 * @mnt->mnt_flags |= MNT_READONLY raised.
1912 *
1913 * (2) MS_RDONLY was passed to the filesystem's mount method and the filesystems
1914 * made the superblock ro. Note, how SB_RDONLY has the same value as
1915 * ms_rdonly and is raised whenever MS_RDONLY is passed through mount(2).
1916 *
1917 * Creating a subtree mount via (iii) ends up leaving a rw superblock with a
1918 * subtree mounted ro.
1919 *
1920 * But consider the effect on the old mount API on btrfs subvolume mounting
1921 * which combines the distinct step in (iii) into a single step.
1922 *
1923 * By issuing (i) both the mount and the superblock are turned ro. Now when (ii)
1924 * is issued the superblock is ro and thus even if the mount created for (ii) is
1925 * rw it wouldn't help. Hence, btrfs needed to transition the superblock from ro
1926 * to rw for (ii) which it did using an internal remount call.
1927 *
1928 * IOW, subvolume mounting was inherently complicated due to the ambiguity of
1929 * MS_RDONLY in mount(2). Note, this ambiguity has mount(8) always translate
1930 * "ro" to MS_RDONLY. IOW, in both (i) and (ii) "ro" becomes MS_RDONLY when
1931 * passed by mount(8) to mount(2).
1932 *
1933 * Enter the new mount API. The new mount API disambiguates making a mount ro
1934 * and making a superblock ro.
1935 *
1936 * (3) To turn a mount ro the MOUNT_ATTR_ONLY flag can be used with either
1937 * fsmount() or mount_setattr() this is a pure VFS level change for a
1938 * specific mount or mount tree that is never seen by the filesystem itself.
1939 *
1940 * (4) To turn a superblock ro the "ro" flag must be used with
1941 * fsconfig(FSCONFIG_SET_FLAG, "ro"). This option is seen by the filesystem
1942 * in fc->sb_flags.
1943 *
1944 * This disambiguation has rather positive consequences. Mounting a subvolume
1945 * ro will not also turn the superblock ro. Only the mount for the subvolume
1946 * will become ro.
1947 *
1948 * So, if the superblock creation request comes from the new mount API the
1949 * caller must have explicitly done:
1950 *
1951 * fsconfig(FSCONFIG_SET_FLAG, "ro")
1952 * fsmount/mount_setattr(MOUNT_ATTR_RDONLY)
1953 *
1954 * IOW, at some point the caller must have explicitly turned the whole
1955 * superblock ro and we shouldn't just undo it like we did for the old mount
1956 * API. In any case, it lets us avoid the hack in the new mount API.
1957 *
1958 * Consequently, the remounting hack must only be used for requests originating
1959 * from the old mount API and should be marked for full deprecation so it can be
1960 * turned off in a couple of years.
1961 *
1962 * The new mount API has no reason to support this hack.
1963 */
1964static struct vfsmount *btrfs_reconfigure_for_mount(struct fs_context *fc)
1965{
1966 struct vfsmount *mnt;
1967 int ret;
1968 const bool ro2rw = !(fc->sb_flags & SB_RDONLY);
1969
1970 /*
1971 * We got an EBUSY because our SB_RDONLY flag didn't match the existing
1972 * super block, so invert our setting here and retry the mount so we
1973 * can get our vfsmount.
1974 */
1975 if (ro2rw)
1976 fc->sb_flags |= SB_RDONLY;
1977 else
1978 fc->sb_flags &= ~SB_RDONLY;
1979
1980 mnt = fc_mount(fc);
1981 if (IS_ERR(mnt))
1982 return mnt;
1983
1984 if (!fc->oldapi || !ro2rw)
1985 return mnt;
1986
1987 /* We need to convert to rw, call reconfigure. */
1988 fc->sb_flags &= ~SB_RDONLY;
1989 down_write(&mnt->mnt_sb->s_umount);
1990 ret = btrfs_reconfigure(fc);
1991 up_write(&mnt->mnt_sb->s_umount);
1992 if (ret) {
1993 mntput(mnt);
1994 return ERR_PTR(ret);
1995 }
1996 return mnt;
1997}
1998
1999static int btrfs_get_tree_subvol(struct fs_context *fc)
2000{
2001 struct btrfs_fs_info *fs_info = NULL;
2002 struct btrfs_fs_context *ctx = fc->fs_private;
2003 struct fs_context *dup_fc;
2004 struct dentry *dentry;
2005 struct vfsmount *mnt;
2006
2007 /*
2008 * Setup a dummy root and fs_info for test/set super. This is because
2009 * we don't actually fill this stuff out until open_ctree, but we need
2010 * then open_ctree will properly initialize the file system specific
2011 * settings later. btrfs_init_fs_info initializes the static elements
2012 * of the fs_info (locks and such) to make cleanup easier if we find a
2013 * superblock with our given fs_devices later on at sget() time.
2014 */
2015 fs_info = kvzalloc(sizeof(struct btrfs_fs_info), GFP_KERNEL);
2016 if (!fs_info)
2017 return -ENOMEM;
2018
2019 fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
2020 fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
2021 if (!fs_info->super_copy || !fs_info->super_for_commit) {
2022 btrfs_free_fs_info(fs_info);
2023 return -ENOMEM;
2024 }
2025 btrfs_init_fs_info(fs_info);
2026
2027 dup_fc = vfs_dup_fs_context(fc);
2028 if (IS_ERR(dup_fc)) {
2029 btrfs_free_fs_info(fs_info);
2030 return PTR_ERR(dup_fc);
2031 }
2032
2033 /*
2034 * When we do the sget_fc this gets transferred to the sb, so we only
2035 * need to set it on the dup_fc as this is what creates the super block.
2036 */
2037 dup_fc->s_fs_info = fs_info;
2038
2039 /*
2040 * We'll do the security settings in our btrfs_get_tree_super() mount
2041 * loop, they were duplicated into dup_fc, we can drop the originals
2042 * here.
2043 */
2044 security_free_mnt_opts(&fc->security);
2045 fc->security = NULL;
2046
2047 mnt = fc_mount(dup_fc);
2048 if (PTR_ERR_OR_ZERO(mnt) == -EBUSY)
2049 mnt = btrfs_reconfigure_for_mount(dup_fc);
2050 put_fs_context(dup_fc);
2051 if (IS_ERR(mnt))
2052 return PTR_ERR(mnt);
2053
2054 /*
2055 * This free's ->subvol_name, because if it isn't set we have to
2056 * allocate a buffer to hold the subvol_name, so we just drop our
2057 * reference to it here.
2058 */
2059 dentry = mount_subvol(ctx->subvol_name, ctx->subvol_objectid, mnt);
2060 ctx->subvol_name = NULL;
2061 if (IS_ERR(dentry))
2062 return PTR_ERR(dentry);
2063
2064 fc->root = dentry;
2065 return 0;
2066}
2067
2068static int btrfs_get_tree(struct fs_context *fc)
2069{
2070 /*
2071 * Since we use mount_subtree to mount the default/specified subvol, we
2072 * have to do mounts in two steps.
2073 *
2074 * First pass through we call btrfs_get_tree_subvol(), this is just a
2075 * wrapper around fc_mount() to call back into here again, and this time
2076 * we'll call btrfs_get_tree_super(). This will do the open_ctree() and
2077 * everything to open the devices and file system. Then we return back
2078 * with a fully constructed vfsmount in btrfs_get_tree_subvol(), and
2079 * from there we can do our mount_subvol() call, which will lookup
2080 * whichever subvol we're mounting and setup this fc with the
2081 * appropriate dentry for the subvol.
2082 */
2083 if (fc->s_fs_info)
2084 return btrfs_get_tree_super(fc);
2085 return btrfs_get_tree_subvol(fc);
2086}
2087
2088static void btrfs_kill_super(struct super_block *sb)
2089{
2090 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2091 kill_anon_super(sb);
2092 btrfs_free_fs_info(fs_info);
2093}
2094
2095static void btrfs_free_fs_context(struct fs_context *fc)
2096{
2097 struct btrfs_fs_context *ctx = fc->fs_private;
2098 struct btrfs_fs_info *fs_info = fc->s_fs_info;
2099
2100 if (fs_info)
2101 btrfs_free_fs_info(fs_info);
2102
2103 if (ctx && refcount_dec_and_test(&ctx->refs)) {
2104 kfree(ctx->subvol_name);
2105 kfree(ctx);
2106 }
2107}
2108
2109static int btrfs_dup_fs_context(struct fs_context *fc, struct fs_context *src_fc)
2110{
2111 struct btrfs_fs_context *ctx = src_fc->fs_private;
2112
2113 /*
2114 * Give a ref to our ctx to this dup, as we want to keep it around for
2115 * our original fc so we can have the subvolume name or objectid.
2116 *
2117 * We unset ->source in the original fc because the dup needs it for
2118 * mounting, and then once we free the dup it'll free ->source, so we
2119 * need to make sure we're only pointing to it in one fc.
2120 */
2121 refcount_inc(&ctx->refs);
2122 fc->fs_private = ctx;
2123 fc->source = src_fc->source;
2124 src_fc->source = NULL;
2125 return 0;
2126}
2127
2128static const struct fs_context_operations btrfs_fs_context_ops = {
2129 .parse_param = btrfs_parse_param,
2130 .reconfigure = btrfs_reconfigure,
2131 .get_tree = btrfs_get_tree,
2132 .dup = btrfs_dup_fs_context,
2133 .free = btrfs_free_fs_context,
2134};
2135
2136static int btrfs_init_fs_context(struct fs_context *fc)
2137{
2138 struct btrfs_fs_context *ctx;
2139
2140 ctx = kzalloc(sizeof(struct btrfs_fs_context), GFP_KERNEL);
2141 if (!ctx)
2142 return -ENOMEM;
2143
2144 refcount_set(&ctx->refs, 1);
2145 fc->fs_private = ctx;
2146 fc->ops = &btrfs_fs_context_ops;
2147
2148 if (fc->purpose == FS_CONTEXT_FOR_RECONFIGURE) {
2149 btrfs_info_to_ctx(btrfs_sb(fc->root->d_sb), ctx);
2150 } else {
2151 ctx->thread_pool_size =
2152 min_t(unsigned long, num_online_cpus() + 2, 8);
2153 ctx->max_inline = BTRFS_DEFAULT_MAX_INLINE;
2154 ctx->commit_interval = BTRFS_DEFAULT_COMMIT_INTERVAL;
2155 }
2156
2157#ifdef CONFIG_BTRFS_FS_POSIX_ACL
2158 fc->sb_flags |= SB_POSIXACL;
2159#endif
2160 fc->sb_flags |= SB_I_VERSION;
2161
2162 return 0;
2163}
2164
2165static struct file_system_type btrfs_fs_type = {
2166 .owner = THIS_MODULE,
2167 .name = "btrfs",
2168 .init_fs_context = btrfs_init_fs_context,
2169 .parameters = btrfs_fs_parameters,
2170 .kill_sb = btrfs_kill_super,
2171 .fs_flags = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA | FS_ALLOW_IDMAP,
2172 };
2173
2174MODULE_ALIAS_FS("btrfs");
2175
2176static int btrfs_control_open(struct inode *inode, struct file *file)
2177{
2178 /*
2179 * The control file's private_data is used to hold the
2180 * transaction when it is started and is used to keep
2181 * track of whether a transaction is already in progress.
2182 */
2183 file->private_data = NULL;
2184 return 0;
2185}
2186
2187/*
2188 * Used by /dev/btrfs-control for devices ioctls.
2189 */
2190static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
2191 unsigned long arg)
2192{
2193 struct btrfs_ioctl_vol_args *vol;
2194 struct btrfs_device *device = NULL;
2195 dev_t devt = 0;
2196 int ret = -ENOTTY;
2197
2198 if (!capable(CAP_SYS_ADMIN))
2199 return -EPERM;
2200
2201 vol = memdup_user((void __user *)arg, sizeof(*vol));
2202 if (IS_ERR(vol))
2203 return PTR_ERR(vol);
2204 ret = btrfs_check_ioctl_vol_args_path(vol);
2205 if (ret < 0)
2206 goto out;
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
2248out:
2249 kfree(vol);
2250 return ret;
2251}
2252
2253static int btrfs_freeze(struct super_block *sb)
2254{
2255 struct btrfs_trans_handle *trans;
2256 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2257 struct btrfs_root *root = fs_info->tree_root;
2258
2259 set_bit(BTRFS_FS_FROZEN, &fs_info->flags);
2260 /*
2261 * We don't need a barrier here, we'll wait for any transaction that
2262 * could be in progress on other threads (and do delayed iputs that
2263 * we want to avoid on a frozen filesystem), or do the commit
2264 * ourselves.
2265 */
2266 trans = btrfs_attach_transaction_barrier(root);
2267 if (IS_ERR(trans)) {
2268 /* no transaction, don't bother */
2269 if (PTR_ERR(trans) == -ENOENT)
2270 return 0;
2271 return PTR_ERR(trans);
2272 }
2273 return btrfs_commit_transaction(trans);
2274}
2275
2276static int check_dev_super(struct btrfs_device *dev)
2277{
2278 struct btrfs_fs_info *fs_info = dev->fs_info;
2279 struct btrfs_super_block *sb;
2280 u64 last_trans;
2281 u16 csum_type;
2282 int ret = 0;
2283
2284 /* This should be called with fs still frozen. */
2285 ASSERT(test_bit(BTRFS_FS_FROZEN, &fs_info->flags));
2286
2287 /* Missing dev, no need to check. */
2288 if (!dev->bdev)
2289 return 0;
2290
2291 /* Only need to check the primary super block. */
2292 sb = btrfs_read_dev_one_super(dev->bdev, 0, true);
2293 if (IS_ERR(sb))
2294 return PTR_ERR(sb);
2295
2296 /* Verify the checksum. */
2297 csum_type = btrfs_super_csum_type(sb);
2298 if (csum_type != btrfs_super_csum_type(fs_info->super_copy)) {
2299 btrfs_err(fs_info, "csum type changed, has %u expect %u",
2300 csum_type, btrfs_super_csum_type(fs_info->super_copy));
2301 ret = -EUCLEAN;
2302 goto out;
2303 }
2304
2305 if (btrfs_check_super_csum(fs_info, sb)) {
2306 btrfs_err(fs_info, "csum for on-disk super block no longer matches");
2307 ret = -EUCLEAN;
2308 goto out;
2309 }
2310
2311 /* Btrfs_validate_super() includes fsid check against super->fsid. */
2312 ret = btrfs_validate_super(fs_info, sb, 0);
2313 if (ret < 0)
2314 goto out;
2315
2316 last_trans = btrfs_get_last_trans_committed(fs_info);
2317 if (btrfs_super_generation(sb) != last_trans) {
2318 btrfs_err(fs_info, "transid mismatch, has %llu expect %llu",
2319 btrfs_super_generation(sb), last_trans);
2320 ret = -EUCLEAN;
2321 goto out;
2322 }
2323out:
2324 btrfs_release_disk_super(sb);
2325 return ret;
2326}
2327
2328static int btrfs_unfreeze(struct super_block *sb)
2329{
2330 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2331 struct btrfs_device *device;
2332 int ret = 0;
2333
2334 /*
2335 * Make sure the fs is not changed by accident (like hibernation then
2336 * modified by other OS).
2337 * If we found anything wrong, we mark the fs error immediately.
2338 *
2339 * And since the fs is frozen, no one can modify the fs yet, thus
2340 * we don't need to hold device_list_mutex.
2341 */
2342 list_for_each_entry(device, &fs_info->fs_devices->devices, dev_list) {
2343 ret = check_dev_super(device);
2344 if (ret < 0) {
2345 btrfs_handle_fs_error(fs_info, ret,
2346 "super block on devid %llu got modified unexpectedly",
2347 device->devid);
2348 break;
2349 }
2350 }
2351 clear_bit(BTRFS_FS_FROZEN, &fs_info->flags);
2352
2353 /*
2354 * We still return 0, to allow VFS layer to unfreeze the fs even the
2355 * above checks failed. Since the fs is either fine or read-only, we're
2356 * safe to continue, without causing further damage.
2357 */
2358 return 0;
2359}
2360
2361static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
2362{
2363 struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
2364
2365 /*
2366 * There should be always a valid pointer in latest_dev, it may be stale
2367 * for a short moment in case it's being deleted but still valid until
2368 * the end of RCU grace period.
2369 */
2370 rcu_read_lock();
2371 seq_escape(m, btrfs_dev_name(fs_info->fs_devices->latest_dev), " \t\n\\");
2372 rcu_read_unlock();
2373
2374 return 0;
2375}
2376
2377static const struct super_operations btrfs_super_ops = {
2378 .drop_inode = btrfs_drop_inode,
2379 .evict_inode = btrfs_evict_inode,
2380 .put_super = btrfs_put_super,
2381 .sync_fs = btrfs_sync_fs,
2382 .show_options = btrfs_show_options,
2383 .show_devname = btrfs_show_devname,
2384 .alloc_inode = btrfs_alloc_inode,
2385 .destroy_inode = btrfs_destroy_inode,
2386 .free_inode = btrfs_free_inode,
2387 .statfs = btrfs_statfs,
2388 .freeze_fs = btrfs_freeze,
2389 .unfreeze_fs = btrfs_unfreeze,
2390};
2391
2392static const struct file_operations btrfs_ctl_fops = {
2393 .open = btrfs_control_open,
2394 .unlocked_ioctl = btrfs_control_ioctl,
2395 .compat_ioctl = compat_ptr_ioctl,
2396 .owner = THIS_MODULE,
2397 .llseek = noop_llseek,
2398};
2399
2400static struct miscdevice btrfs_misc = {
2401 .minor = BTRFS_MINOR,
2402 .name = "btrfs-control",
2403 .fops = &btrfs_ctl_fops
2404};
2405
2406MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
2407MODULE_ALIAS("devname:btrfs-control");
2408
2409static int __init btrfs_interface_init(void)
2410{
2411 return misc_register(&btrfs_misc);
2412}
2413
2414static __cold void btrfs_interface_exit(void)
2415{
2416 misc_deregister(&btrfs_misc);
2417}
2418
2419static int __init btrfs_print_mod_info(void)
2420{
2421 static const char options[] = ""
2422#ifdef CONFIG_BTRFS_DEBUG
2423 ", debug=on"
2424#endif
2425#ifdef CONFIG_BTRFS_ASSERT
2426 ", assert=on"
2427#endif
2428#ifdef CONFIG_BTRFS_FS_REF_VERIFY
2429 ", ref-verify=on"
2430#endif
2431#ifdef CONFIG_BLK_DEV_ZONED
2432 ", zoned=yes"
2433#else
2434 ", zoned=no"
2435#endif
2436#ifdef CONFIG_FS_VERITY
2437 ", fsverity=yes"
2438#else
2439 ", fsverity=no"
2440#endif
2441 ;
2442 pr_info("Btrfs loaded%s\n", options);
2443 return 0;
2444}
2445
2446static int register_btrfs(void)
2447{
2448 return register_filesystem(&btrfs_fs_type);
2449}
2450
2451static void unregister_btrfs(void)
2452{
2453 unregister_filesystem(&btrfs_fs_type);
2454}
2455
2456/* Helper structure for long init/exit functions. */
2457struct init_sequence {
2458 int (*init_func)(void);
2459 /* Can be NULL if the init_func doesn't need cleanup. */
2460 void (*exit_func)(void);
2461};
2462
2463static const struct init_sequence mod_init_seq[] = {
2464 {
2465 .init_func = btrfs_props_init,
2466 .exit_func = NULL,
2467 }, {
2468 .init_func = btrfs_init_sysfs,
2469 .exit_func = btrfs_exit_sysfs,
2470 }, {
2471 .init_func = btrfs_init_compress,
2472 .exit_func = btrfs_exit_compress,
2473 }, {
2474 .init_func = btrfs_init_cachep,
2475 .exit_func = btrfs_destroy_cachep,
2476 }, {
2477 .init_func = btrfs_transaction_init,
2478 .exit_func = btrfs_transaction_exit,
2479 }, {
2480 .init_func = btrfs_ctree_init,
2481 .exit_func = btrfs_ctree_exit,
2482 }, {
2483 .init_func = btrfs_free_space_init,
2484 .exit_func = btrfs_free_space_exit,
2485 }, {
2486 .init_func = extent_state_init_cachep,
2487 .exit_func = extent_state_free_cachep,
2488 }, {
2489 .init_func = extent_buffer_init_cachep,
2490 .exit_func = extent_buffer_free_cachep,
2491 }, {
2492 .init_func = btrfs_bioset_init,
2493 .exit_func = btrfs_bioset_exit,
2494 }, {
2495 .init_func = extent_map_init,
2496 .exit_func = extent_map_exit,
2497 }, {
2498 .init_func = ordered_data_init,
2499 .exit_func = ordered_data_exit,
2500 }, {
2501 .init_func = btrfs_delayed_inode_init,
2502 .exit_func = btrfs_delayed_inode_exit,
2503 }, {
2504 .init_func = btrfs_auto_defrag_init,
2505 .exit_func = btrfs_auto_defrag_exit,
2506 }, {
2507 .init_func = btrfs_delayed_ref_init,
2508 .exit_func = btrfs_delayed_ref_exit,
2509 }, {
2510 .init_func = btrfs_prelim_ref_init,
2511 .exit_func = btrfs_prelim_ref_exit,
2512 }, {
2513 .init_func = btrfs_interface_init,
2514 .exit_func = btrfs_interface_exit,
2515 }, {
2516 .init_func = btrfs_print_mod_info,
2517 .exit_func = NULL,
2518 }, {
2519 .init_func = btrfs_run_sanity_tests,
2520 .exit_func = NULL,
2521 }, {
2522 .init_func = register_btrfs,
2523 .exit_func = unregister_btrfs,
2524 }
2525};
2526
2527static bool mod_init_result[ARRAY_SIZE(mod_init_seq)];
2528
2529static __always_inline void btrfs_exit_btrfs_fs(void)
2530{
2531 int i;
2532
2533 for (i = ARRAY_SIZE(mod_init_seq) - 1; i >= 0; i--) {
2534 if (!mod_init_result[i])
2535 continue;
2536 if (mod_init_seq[i].exit_func)
2537 mod_init_seq[i].exit_func();
2538 mod_init_result[i] = false;
2539 }
2540}
2541
2542static void __exit exit_btrfs_fs(void)
2543{
2544 btrfs_exit_btrfs_fs();
2545 btrfs_cleanup_fs_uuids();
2546}
2547
2548static int __init init_btrfs_fs(void)
2549{
2550 int ret;
2551 int i;
2552
2553 for (i = 0; i < ARRAY_SIZE(mod_init_seq); i++) {
2554 ASSERT(!mod_init_result[i]);
2555 ret = mod_init_seq[i].init_func();
2556 if (ret < 0) {
2557 btrfs_exit_btrfs_fs();
2558 return ret;
2559 }
2560 mod_init_result[i] = true;
2561 }
2562 return 0;
2563}
2564
2565late_initcall(init_btrfs_fs);
2566module_exit(exit_btrfs_fs)
2567
2568MODULE_LICENSE("GPL");
2569MODULE_SOFTDEP("pre: crc32c");
2570MODULE_SOFTDEP("pre: xxhash64");
2571MODULE_SOFTDEP("pre: sha256");
2572MODULE_SOFTDEP("pre: blake2b-256");