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