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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 "direct-io.h"
38#include "props.h"
39#include "xattr.h"
40#include "bio.h"
41#include "export.h"
42#include "compression.h"
43#include "dev-replace.h"
44#include "free-space-cache.h"
45#include "backref.h"
46#include "space-info.h"
47#include "sysfs.h"
48#include "zoned.h"
49#include "tests/btrfs-tests.h"
50#include "block-group.h"
51#include "discard.h"
52#include "qgroup.h"
53#include "raid56.h"
54#include "fs.h"
55#include "accessors.h"
56#include "defrag.h"
57#include "dir-item.h"
58#include "ioctl.h"
59#include "scrub.h"
60#include "verity.h"
61#include "super.h"
62#include "extent-tree.h"
63#define CREATE_TRACE_POINTS
64#include <trace/events/btrfs.h>
65
66static const struct super_operations btrfs_super_ops;
67static struct file_system_type btrfs_fs_type;
68
69static void btrfs_put_super(struct super_block *sb)
70{
71 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
72
73 btrfs_info(fs_info, "last unmount of filesystem %pU", fs_info->fs_devices->fsid);
74 close_ctree(fs_info);
75}
76
77/* Store the mount options related information. */
78struct btrfs_fs_context {
79 char *subvol_name;
80 u64 subvol_objectid;
81 u64 max_inline;
82 u32 commit_interval;
83 u32 metadata_ratio;
84 u32 thread_pool_size;
85 unsigned long long mount_opt;
86 unsigned long compress_type:4;
87 unsigned int compress_level;
88 refcount_t refs;
89};
90
91enum {
92 Opt_acl,
93 Opt_clear_cache,
94 Opt_commit_interval,
95 Opt_compress,
96 Opt_compress_force,
97 Opt_compress_force_type,
98 Opt_compress_type,
99 Opt_degraded,
100 Opt_device,
101 Opt_fatal_errors,
102 Opt_flushoncommit,
103 Opt_max_inline,
104 Opt_barrier,
105 Opt_datacow,
106 Opt_datasum,
107 Opt_defrag,
108 Opt_discard,
109 Opt_discard_mode,
110 Opt_ratio,
111 Opt_rescan_uuid_tree,
112 Opt_skip_balance,
113 Opt_space_cache,
114 Opt_space_cache_version,
115 Opt_ssd,
116 Opt_ssd_spread,
117 Opt_subvol,
118 Opt_subvol_empty,
119 Opt_subvolid,
120 Opt_thread_pool,
121 Opt_treelog,
122 Opt_user_subvol_rm_allowed,
123 Opt_norecovery,
124
125 /* Rescue options */
126 Opt_rescue,
127 Opt_usebackuproot,
128 Opt_nologreplay,
129
130 /* Debugging options */
131 Opt_enospc_debug,
132#ifdef CONFIG_BTRFS_DEBUG
133 Opt_fragment, Opt_fragment_data, Opt_fragment_metadata, Opt_fragment_all,
134#endif
135#ifdef CONFIG_BTRFS_FS_REF_VERIFY
136 Opt_ref_verify,
137#endif
138 Opt_err,
139};
140
141enum {
142 Opt_fatal_errors_panic,
143 Opt_fatal_errors_bug,
144};
145
146static const struct constant_table btrfs_parameter_fatal_errors[] = {
147 { "panic", Opt_fatal_errors_panic },
148 { "bug", Opt_fatal_errors_bug },
149 {}
150};
151
152enum {
153 Opt_discard_sync,
154 Opt_discard_async,
155};
156
157static const struct constant_table btrfs_parameter_discard[] = {
158 { "sync", Opt_discard_sync },
159 { "async", Opt_discard_async },
160 {}
161};
162
163enum {
164 Opt_space_cache_v1,
165 Opt_space_cache_v2,
166};
167
168static const struct constant_table btrfs_parameter_space_cache[] = {
169 { "v1", Opt_space_cache_v1 },
170 { "v2", Opt_space_cache_v2 },
171 {}
172};
173
174enum {
175 Opt_rescue_usebackuproot,
176 Opt_rescue_nologreplay,
177 Opt_rescue_ignorebadroots,
178 Opt_rescue_ignoredatacsums,
179 Opt_rescue_ignoremetacsums,
180 Opt_rescue_ignoresuperflags,
181 Opt_rescue_parameter_all,
182};
183
184static const struct constant_table btrfs_parameter_rescue[] = {
185 { "usebackuproot", Opt_rescue_usebackuproot },
186 { "nologreplay", Opt_rescue_nologreplay },
187 { "ignorebadroots", Opt_rescue_ignorebadroots },
188 { "ibadroots", Opt_rescue_ignorebadroots },
189 { "ignoredatacsums", Opt_rescue_ignoredatacsums },
190 { "ignoremetacsums", Opt_rescue_ignoremetacsums},
191 { "ignoresuperflags", Opt_rescue_ignoresuperflags},
192 { "idatacsums", Opt_rescue_ignoredatacsums },
193 { "imetacsums", Opt_rescue_ignoremetacsums},
194 { "isuperflags", Opt_rescue_ignoresuperflags},
195 { "all", Opt_rescue_parameter_all },
196 {}
197};
198
199#ifdef CONFIG_BTRFS_DEBUG
200enum {
201 Opt_fragment_parameter_data,
202 Opt_fragment_parameter_metadata,
203 Opt_fragment_parameter_all,
204};
205
206static const struct constant_table btrfs_parameter_fragment[] = {
207 { "data", Opt_fragment_parameter_data },
208 { "metadata", Opt_fragment_parameter_metadata },
209 { "all", Opt_fragment_parameter_all },
210 {}
211};
212#endif
213
214static const struct fs_parameter_spec btrfs_fs_parameters[] = {
215 fsparam_flag_no("acl", Opt_acl),
216 fsparam_flag_no("autodefrag", Opt_defrag),
217 fsparam_flag_no("barrier", Opt_barrier),
218 fsparam_flag("clear_cache", Opt_clear_cache),
219 fsparam_u32("commit", Opt_commit_interval),
220 fsparam_flag("compress", Opt_compress),
221 fsparam_string("compress", Opt_compress_type),
222 fsparam_flag("compress-force", Opt_compress_force),
223 fsparam_string("compress-force", Opt_compress_force_type),
224 fsparam_flag_no("datacow", Opt_datacow),
225 fsparam_flag_no("datasum", Opt_datasum),
226 fsparam_flag("degraded", Opt_degraded),
227 fsparam_string("device", Opt_device),
228 fsparam_flag_no("discard", Opt_discard),
229 fsparam_enum("discard", Opt_discard_mode, btrfs_parameter_discard),
230 fsparam_enum("fatal_errors", Opt_fatal_errors, btrfs_parameter_fatal_errors),
231 fsparam_flag_no("flushoncommit", Opt_flushoncommit),
232 fsparam_string("max_inline", Opt_max_inline),
233 fsparam_u32("metadata_ratio", Opt_ratio),
234 fsparam_flag("rescan_uuid_tree", Opt_rescan_uuid_tree),
235 fsparam_flag("skip_balance", Opt_skip_balance),
236 fsparam_flag_no("space_cache", Opt_space_cache),
237 fsparam_enum("space_cache", Opt_space_cache_version, btrfs_parameter_space_cache),
238 fsparam_flag_no("ssd", Opt_ssd),
239 fsparam_flag_no("ssd_spread", Opt_ssd_spread),
240 fsparam_string("subvol", Opt_subvol),
241 fsparam_flag("subvol=", Opt_subvol_empty),
242 fsparam_u64("subvolid", Opt_subvolid),
243 fsparam_u32("thread_pool", Opt_thread_pool),
244 fsparam_flag_no("treelog", Opt_treelog),
245 fsparam_flag("user_subvol_rm_allowed", Opt_user_subvol_rm_allowed),
246
247 /* Rescue options. */
248 fsparam_enum("rescue", Opt_rescue, btrfs_parameter_rescue),
249 /* Deprecated, with alias rescue=nologreplay */
250 __fsparam(NULL, "nologreplay", Opt_nologreplay, fs_param_deprecated, NULL),
251 /* Deprecated, with alias rescue=usebackuproot */
252 __fsparam(NULL, "usebackuproot", Opt_usebackuproot, fs_param_deprecated, NULL),
253 /* For compatibility only, alias for "rescue=nologreplay". */
254 fsparam_flag("norecovery", Opt_norecovery),
255
256 /* Debugging options. */
257 fsparam_flag_no("enospc_debug", Opt_enospc_debug),
258#ifdef CONFIG_BTRFS_DEBUG
259 fsparam_enum("fragment", Opt_fragment, btrfs_parameter_fragment),
260#endif
261#ifdef CONFIG_BTRFS_FS_REF_VERIFY
262 fsparam_flag("ref_verify", Opt_ref_verify),
263#endif
264 {}
265};
266
267/* No support for restricting writes to btrfs devices yet... */
268static inline blk_mode_t btrfs_open_mode(struct fs_context *fc)
269{
270 return sb_open_mode(fc->sb_flags) & ~BLK_OPEN_RESTRICT_WRITES;
271}
272
273static int btrfs_parse_param(struct fs_context *fc, struct fs_parameter *param)
274{
275 struct btrfs_fs_context *ctx = fc->fs_private;
276 struct fs_parse_result result;
277 int opt;
278
279 opt = fs_parse(fc, btrfs_fs_parameters, param, &result);
280 if (opt < 0)
281 return opt;
282
283 switch (opt) {
284 case Opt_degraded:
285 btrfs_set_opt(ctx->mount_opt, DEGRADED);
286 break;
287 case Opt_subvol_empty:
288 /*
289 * This exists because we used to allow it on accident, so we're
290 * keeping it to maintain ABI. See 37becec95ac3 ("Btrfs: allow
291 * empty subvol= again").
292 */
293 break;
294 case Opt_subvol:
295 kfree(ctx->subvol_name);
296 ctx->subvol_name = kstrdup(param->string, GFP_KERNEL);
297 if (!ctx->subvol_name)
298 return -ENOMEM;
299 break;
300 case Opt_subvolid:
301 ctx->subvol_objectid = result.uint_64;
302
303 /* subvolid=0 means give me the original fs_tree. */
304 if (!ctx->subvol_objectid)
305 ctx->subvol_objectid = BTRFS_FS_TREE_OBJECTID;
306 break;
307 case Opt_device: {
308 struct btrfs_device *device;
309 blk_mode_t mode = btrfs_open_mode(fc);
310
311 mutex_lock(&uuid_mutex);
312 device = btrfs_scan_one_device(param->string, mode, false);
313 mutex_unlock(&uuid_mutex);
314 if (IS_ERR(device))
315 return PTR_ERR(device);
316 break;
317 }
318 case Opt_datasum:
319 if (result.negated) {
320 btrfs_set_opt(ctx->mount_opt, NODATASUM);
321 } else {
322 btrfs_clear_opt(ctx->mount_opt, NODATACOW);
323 btrfs_clear_opt(ctx->mount_opt, NODATASUM);
324 }
325 break;
326 case Opt_datacow:
327 if (result.negated) {
328 btrfs_clear_opt(ctx->mount_opt, COMPRESS);
329 btrfs_clear_opt(ctx->mount_opt, FORCE_COMPRESS);
330 btrfs_set_opt(ctx->mount_opt, NODATACOW);
331 btrfs_set_opt(ctx->mount_opt, NODATASUM);
332 } else {
333 btrfs_clear_opt(ctx->mount_opt, NODATACOW);
334 }
335 break;
336 case Opt_compress_force:
337 case Opt_compress_force_type:
338 btrfs_set_opt(ctx->mount_opt, FORCE_COMPRESS);
339 fallthrough;
340 case Opt_compress:
341 case Opt_compress_type:
342 /*
343 * Provide the same semantics as older kernels that don't use fs
344 * context, specifying the "compress" option clears
345 * "force-compress" without the need to pass
346 * "compress-force=[no|none]" before specifying "compress".
347 */
348 if (opt != Opt_compress_force && opt != Opt_compress_force_type)
349 btrfs_clear_opt(ctx->mount_opt, FORCE_COMPRESS);
350
351 if (opt == Opt_compress || opt == Opt_compress_force) {
352 ctx->compress_type = BTRFS_COMPRESS_ZLIB;
353 ctx->compress_level = BTRFS_ZLIB_DEFAULT_LEVEL;
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, "zlib", 4) == 0) {
358 ctx->compress_type = BTRFS_COMPRESS_ZLIB;
359 ctx->compress_level =
360 btrfs_compress_str2level(BTRFS_COMPRESS_ZLIB,
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, "lzo", 3) == 0) {
366 ctx->compress_type = BTRFS_COMPRESS_LZO;
367 ctx->compress_level = 0;
368 btrfs_set_opt(ctx->mount_opt, COMPRESS);
369 btrfs_clear_opt(ctx->mount_opt, NODATACOW);
370 btrfs_clear_opt(ctx->mount_opt, NODATASUM);
371 } else if (strncmp(param->string, "zstd", 4) == 0) {
372 ctx->compress_type = BTRFS_COMPRESS_ZSTD;
373 ctx->compress_level =
374 btrfs_compress_str2level(BTRFS_COMPRESS_ZSTD,
375 param->string + 4);
376 btrfs_set_opt(ctx->mount_opt, COMPRESS);
377 btrfs_clear_opt(ctx->mount_opt, NODATACOW);
378 btrfs_clear_opt(ctx->mount_opt, NODATASUM);
379 } else if (strncmp(param->string, "no", 2) == 0) {
380 ctx->compress_level = 0;
381 ctx->compress_type = 0;
382 btrfs_clear_opt(ctx->mount_opt, COMPRESS);
383 btrfs_clear_opt(ctx->mount_opt, FORCE_COMPRESS);
384 } else {
385 btrfs_err(NULL, "unrecognized compression value %s",
386 param->string);
387 return -EINVAL;
388 }
389 break;
390 case Opt_ssd:
391 if (result.negated) {
392 btrfs_set_opt(ctx->mount_opt, NOSSD);
393 btrfs_clear_opt(ctx->mount_opt, SSD);
394 btrfs_clear_opt(ctx->mount_opt, SSD_SPREAD);
395 } else {
396 btrfs_set_opt(ctx->mount_opt, SSD);
397 btrfs_clear_opt(ctx->mount_opt, NOSSD);
398 }
399 break;
400 case Opt_ssd_spread:
401 if (result.negated) {
402 btrfs_clear_opt(ctx->mount_opt, SSD_SPREAD);
403 } else {
404 btrfs_set_opt(ctx->mount_opt, SSD);
405 btrfs_set_opt(ctx->mount_opt, SSD_SPREAD);
406 btrfs_clear_opt(ctx->mount_opt, NOSSD);
407 }
408 break;
409 case Opt_barrier:
410 if (result.negated)
411 btrfs_set_opt(ctx->mount_opt, NOBARRIER);
412 else
413 btrfs_clear_opt(ctx->mount_opt, NOBARRIER);
414 break;
415 case Opt_thread_pool:
416 if (result.uint_32 == 0) {
417 btrfs_err(NULL, "invalid value 0 for thread_pool");
418 return -EINVAL;
419 }
420 ctx->thread_pool_size = result.uint_32;
421 break;
422 case Opt_max_inline:
423 ctx->max_inline = memparse(param->string, NULL);
424 break;
425 case Opt_acl:
426 if (result.negated) {
427 fc->sb_flags &= ~SB_POSIXACL;
428 } else {
429#ifdef CONFIG_BTRFS_FS_POSIX_ACL
430 fc->sb_flags |= SB_POSIXACL;
431#else
432 btrfs_err(NULL, "support for ACL not compiled in");
433 return -EINVAL;
434#endif
435 }
436 /*
437 * VFS limits the ability to toggle ACL on and off via remount,
438 * despite every file system allowing this. This seems to be
439 * an oversight since we all do, but it'll fail if we're
440 * remounting. So don't set the mask here, we'll check it in
441 * btrfs_reconfigure and do the toggling ourselves.
442 */
443 if (fc->purpose != FS_CONTEXT_FOR_RECONFIGURE)
444 fc->sb_flags_mask |= SB_POSIXACL;
445 break;
446 case Opt_treelog:
447 if (result.negated)
448 btrfs_set_opt(ctx->mount_opt, NOTREELOG);
449 else
450 btrfs_clear_opt(ctx->mount_opt, NOTREELOG);
451 break;
452 case Opt_nologreplay:
453 btrfs_warn(NULL,
454 "'nologreplay' is deprecated, use 'rescue=nologreplay' instead");
455 btrfs_set_opt(ctx->mount_opt, NOLOGREPLAY);
456 break;
457 case Opt_norecovery:
458 btrfs_info(NULL,
459"'norecovery' is for compatibility only, recommended to use 'rescue=nologreplay'");
460 btrfs_set_opt(ctx->mount_opt, NOLOGREPLAY);
461 break;
462 case Opt_flushoncommit:
463 if (result.negated)
464 btrfs_clear_opt(ctx->mount_opt, FLUSHONCOMMIT);
465 else
466 btrfs_set_opt(ctx->mount_opt, FLUSHONCOMMIT);
467 break;
468 case Opt_ratio:
469 ctx->metadata_ratio = result.uint_32;
470 break;
471 case Opt_discard:
472 if (result.negated) {
473 btrfs_clear_opt(ctx->mount_opt, DISCARD_SYNC);
474 btrfs_clear_opt(ctx->mount_opt, DISCARD_ASYNC);
475 btrfs_set_opt(ctx->mount_opt, NODISCARD);
476 } else {
477 btrfs_set_opt(ctx->mount_opt, DISCARD_SYNC);
478 btrfs_clear_opt(ctx->mount_opt, DISCARD_ASYNC);
479 }
480 break;
481 case Opt_discard_mode:
482 switch (result.uint_32) {
483 case Opt_discard_sync:
484 btrfs_clear_opt(ctx->mount_opt, DISCARD_ASYNC);
485 btrfs_set_opt(ctx->mount_opt, DISCARD_SYNC);
486 break;
487 case Opt_discard_async:
488 btrfs_clear_opt(ctx->mount_opt, DISCARD_SYNC);
489 btrfs_set_opt(ctx->mount_opt, DISCARD_ASYNC);
490 break;
491 default:
492 btrfs_err(NULL, "unrecognized discard mode value %s",
493 param->key);
494 return -EINVAL;
495 }
496 btrfs_clear_opt(ctx->mount_opt, NODISCARD);
497 break;
498 case Opt_space_cache:
499 if (result.negated) {
500 btrfs_set_opt(ctx->mount_opt, NOSPACECACHE);
501 btrfs_clear_opt(ctx->mount_opt, SPACE_CACHE);
502 btrfs_clear_opt(ctx->mount_opt, FREE_SPACE_TREE);
503 } else {
504 btrfs_clear_opt(ctx->mount_opt, FREE_SPACE_TREE);
505 btrfs_set_opt(ctx->mount_opt, SPACE_CACHE);
506 }
507 break;
508 case Opt_space_cache_version:
509 switch (result.uint_32) {
510 case Opt_space_cache_v1:
511 btrfs_set_opt(ctx->mount_opt, SPACE_CACHE);
512 btrfs_clear_opt(ctx->mount_opt, FREE_SPACE_TREE);
513 break;
514 case Opt_space_cache_v2:
515 btrfs_clear_opt(ctx->mount_opt, SPACE_CACHE);
516 btrfs_set_opt(ctx->mount_opt, FREE_SPACE_TREE);
517 break;
518 default:
519 btrfs_err(NULL, "unrecognized space_cache value %s",
520 param->key);
521 return -EINVAL;
522 }
523 break;
524 case Opt_rescan_uuid_tree:
525 btrfs_set_opt(ctx->mount_opt, RESCAN_UUID_TREE);
526 break;
527 case Opt_clear_cache:
528 btrfs_set_opt(ctx->mount_opt, CLEAR_CACHE);
529 break;
530 case Opt_user_subvol_rm_allowed:
531 btrfs_set_opt(ctx->mount_opt, USER_SUBVOL_RM_ALLOWED);
532 break;
533 case Opt_enospc_debug:
534 if (result.negated)
535 btrfs_clear_opt(ctx->mount_opt, ENOSPC_DEBUG);
536 else
537 btrfs_set_opt(ctx->mount_opt, ENOSPC_DEBUG);
538 break;
539 case Opt_defrag:
540 if (result.negated)
541 btrfs_clear_opt(ctx->mount_opt, AUTO_DEFRAG);
542 else
543 btrfs_set_opt(ctx->mount_opt, AUTO_DEFRAG);
544 break;
545 case Opt_usebackuproot:
546 btrfs_warn(NULL,
547 "'usebackuproot' is deprecated, use 'rescue=usebackuproot' instead");
548 btrfs_set_opt(ctx->mount_opt, USEBACKUPROOT);
549
550 /* If we're loading the backup roots we can't trust the space cache. */
551 btrfs_set_opt(ctx->mount_opt, CLEAR_CACHE);
552 break;
553 case Opt_skip_balance:
554 btrfs_set_opt(ctx->mount_opt, SKIP_BALANCE);
555 break;
556 case Opt_fatal_errors:
557 switch (result.uint_32) {
558 case Opt_fatal_errors_panic:
559 btrfs_set_opt(ctx->mount_opt, PANIC_ON_FATAL_ERROR);
560 break;
561 case Opt_fatal_errors_bug:
562 btrfs_clear_opt(ctx->mount_opt, PANIC_ON_FATAL_ERROR);
563 break;
564 default:
565 btrfs_err(NULL, "unrecognized fatal_errors value %s",
566 param->key);
567 return -EINVAL;
568 }
569 break;
570 case Opt_commit_interval:
571 ctx->commit_interval = result.uint_32;
572 if (ctx->commit_interval == 0)
573 ctx->commit_interval = BTRFS_DEFAULT_COMMIT_INTERVAL;
574 break;
575 case Opt_rescue:
576 switch (result.uint_32) {
577 case Opt_rescue_usebackuproot:
578 btrfs_set_opt(ctx->mount_opt, USEBACKUPROOT);
579 break;
580 case Opt_rescue_nologreplay:
581 btrfs_set_opt(ctx->mount_opt, NOLOGREPLAY);
582 break;
583 case Opt_rescue_ignorebadroots:
584 btrfs_set_opt(ctx->mount_opt, IGNOREBADROOTS);
585 break;
586 case Opt_rescue_ignoredatacsums:
587 btrfs_set_opt(ctx->mount_opt, IGNOREDATACSUMS);
588 break;
589 case Opt_rescue_ignoremetacsums:
590 btrfs_set_opt(ctx->mount_opt, IGNOREMETACSUMS);
591 break;
592 case Opt_rescue_ignoresuperflags:
593 btrfs_set_opt(ctx->mount_opt, IGNORESUPERFLAGS);
594 break;
595 case Opt_rescue_parameter_all:
596 btrfs_set_opt(ctx->mount_opt, IGNOREDATACSUMS);
597 btrfs_set_opt(ctx->mount_opt, IGNOREMETACSUMS);
598 btrfs_set_opt(ctx->mount_opt, IGNORESUPERFLAGS);
599 btrfs_set_opt(ctx->mount_opt, IGNOREBADROOTS);
600 btrfs_set_opt(ctx->mount_opt, NOLOGREPLAY);
601 break;
602 default:
603 btrfs_info(NULL, "unrecognized rescue option '%s'",
604 param->key);
605 return -EINVAL;
606 }
607 break;
608#ifdef CONFIG_BTRFS_DEBUG
609 case Opt_fragment:
610 switch (result.uint_32) {
611 case Opt_fragment_parameter_all:
612 btrfs_set_opt(ctx->mount_opt, FRAGMENT_DATA);
613 btrfs_set_opt(ctx->mount_opt, FRAGMENT_METADATA);
614 break;
615 case Opt_fragment_parameter_metadata:
616 btrfs_set_opt(ctx->mount_opt, FRAGMENT_METADATA);
617 break;
618 case Opt_fragment_parameter_data:
619 btrfs_set_opt(ctx->mount_opt, FRAGMENT_DATA);
620 break;
621 default:
622 btrfs_info(NULL, "unrecognized fragment option '%s'",
623 param->key);
624 return -EINVAL;
625 }
626 break;
627#endif
628#ifdef CONFIG_BTRFS_FS_REF_VERIFY
629 case Opt_ref_verify:
630 btrfs_set_opt(ctx->mount_opt, REF_VERIFY);
631 break;
632#endif
633 default:
634 btrfs_err(NULL, "unrecognized mount option '%s'", param->key);
635 return -EINVAL;
636 }
637
638 return 0;
639}
640
641/*
642 * Some options only have meaning at mount time and shouldn't persist across
643 * remounts, or be displayed. Clear these at the end of mount and remount code
644 * paths.
645 */
646static void btrfs_clear_oneshot_options(struct btrfs_fs_info *fs_info)
647{
648 btrfs_clear_opt(fs_info->mount_opt, USEBACKUPROOT);
649 btrfs_clear_opt(fs_info->mount_opt, CLEAR_CACHE);
650 btrfs_clear_opt(fs_info->mount_opt, NOSPACECACHE);
651}
652
653static bool check_ro_option(const struct btrfs_fs_info *fs_info,
654 unsigned long long mount_opt, unsigned long long opt,
655 const char *opt_name)
656{
657 if (mount_opt & opt) {
658 btrfs_err(fs_info, "%s must be used with ro mount option",
659 opt_name);
660 return true;
661 }
662 return false;
663}
664
665bool btrfs_check_options(const struct btrfs_fs_info *info,
666 unsigned long long *mount_opt,
667 unsigned long flags)
668{
669 bool ret = true;
670
671 if (!(flags & SB_RDONLY) &&
672 (check_ro_option(info, *mount_opt, BTRFS_MOUNT_NOLOGREPLAY, "nologreplay") ||
673 check_ro_option(info, *mount_opt, BTRFS_MOUNT_IGNOREBADROOTS, "ignorebadroots") ||
674 check_ro_option(info, *mount_opt, BTRFS_MOUNT_IGNOREDATACSUMS, "ignoredatacsums") ||
675 check_ro_option(info, *mount_opt, BTRFS_MOUNT_IGNOREMETACSUMS, "ignoremetacsums") ||
676 check_ro_option(info, *mount_opt, BTRFS_MOUNT_IGNORESUPERFLAGS, "ignoresuperflags")))
677 ret = false;
678
679 if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE) &&
680 !btrfs_raw_test_opt(*mount_opt, FREE_SPACE_TREE) &&
681 !btrfs_raw_test_opt(*mount_opt, CLEAR_CACHE)) {
682 btrfs_err(info, "cannot disable free-space-tree");
683 ret = false;
684 }
685 if (btrfs_fs_compat_ro(info, BLOCK_GROUP_TREE) &&
686 !btrfs_raw_test_opt(*mount_opt, FREE_SPACE_TREE)) {
687 btrfs_err(info, "cannot disable free-space-tree with block-group-tree feature");
688 ret = false;
689 }
690
691 if (btrfs_check_mountopts_zoned(info, mount_opt))
692 ret = false;
693
694 if (!test_bit(BTRFS_FS_STATE_REMOUNTING, &info->fs_state)) {
695 if (btrfs_raw_test_opt(*mount_opt, SPACE_CACHE)) {
696 btrfs_info(info, "disk space caching is enabled");
697 btrfs_warn(info,
698"space cache v1 is being deprecated and will be removed in a future release, please use -o space_cache=v2");
699 }
700 if (btrfs_raw_test_opt(*mount_opt, FREE_SPACE_TREE))
701 btrfs_info(info, "using free-space-tree");
702 }
703
704 return ret;
705}
706
707/*
708 * This is subtle, we only call this during open_ctree(). We need to pre-load
709 * the mount options with the on-disk settings. Before the new mount API took
710 * effect we would do this on mount and remount. With the new mount API we'll
711 * only do this on the initial mount.
712 *
713 * This isn't a change in behavior, because we're using the current state of the
714 * file system to set the current mount options. If you mounted with special
715 * options to disable these features and then remounted we wouldn't revert the
716 * settings, because mounting without these features cleared the on-disk
717 * settings, so this being called on re-mount is not needed.
718 */
719void btrfs_set_free_space_cache_settings(struct btrfs_fs_info *fs_info)
720{
721 if (fs_info->sectorsize < PAGE_SIZE) {
722 btrfs_clear_opt(fs_info->mount_opt, SPACE_CACHE);
723 if (!btrfs_test_opt(fs_info, FREE_SPACE_TREE)) {
724 btrfs_info(fs_info,
725 "forcing free space tree for sector size %u with page size %lu",
726 fs_info->sectorsize, PAGE_SIZE);
727 btrfs_set_opt(fs_info->mount_opt, FREE_SPACE_TREE);
728 }
729 }
730
731 /*
732 * At this point our mount options are populated, so we only mess with
733 * these settings if we don't have any settings already.
734 */
735 if (btrfs_test_opt(fs_info, FREE_SPACE_TREE))
736 return;
737
738 if (btrfs_is_zoned(fs_info) &&
739 btrfs_free_space_cache_v1_active(fs_info)) {
740 btrfs_info(fs_info, "zoned: clearing existing space cache");
741 btrfs_set_super_cache_generation(fs_info->super_copy, 0);
742 return;
743 }
744
745 if (btrfs_test_opt(fs_info, SPACE_CACHE))
746 return;
747
748 if (btrfs_test_opt(fs_info, NOSPACECACHE))
749 return;
750
751 /*
752 * At this point we don't have explicit options set by the user, set
753 * them ourselves based on the state of the file system.
754 */
755 if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
756 btrfs_set_opt(fs_info->mount_opt, FREE_SPACE_TREE);
757 else if (btrfs_free_space_cache_v1_active(fs_info))
758 btrfs_set_opt(fs_info->mount_opt, SPACE_CACHE);
759}
760
761static void set_device_specific_options(struct btrfs_fs_info *fs_info)
762{
763 if (!btrfs_test_opt(fs_info, NOSSD) &&
764 !fs_info->fs_devices->rotating)
765 btrfs_set_opt(fs_info->mount_opt, SSD);
766
767 /*
768 * For devices supporting discard turn on discard=async automatically,
769 * unless it's already set or disabled. This could be turned off by
770 * nodiscard for the same mount.
771 *
772 * The zoned mode piggy backs on the discard functionality for
773 * resetting a zone. There is no reason to delay the zone reset as it is
774 * fast enough. So, do not enable async discard for zoned mode.
775 */
776 if (!(btrfs_test_opt(fs_info, DISCARD_SYNC) ||
777 btrfs_test_opt(fs_info, DISCARD_ASYNC) ||
778 btrfs_test_opt(fs_info, NODISCARD)) &&
779 fs_info->fs_devices->discardable &&
780 !btrfs_is_zoned(fs_info))
781 btrfs_set_opt(fs_info->mount_opt, DISCARD_ASYNC);
782}
783
784char *btrfs_get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
785 u64 subvol_objectid)
786{
787 struct btrfs_root *root = fs_info->tree_root;
788 struct btrfs_root *fs_root = NULL;
789 struct btrfs_root_ref *root_ref;
790 struct btrfs_inode_ref *inode_ref;
791 struct btrfs_key key;
792 struct btrfs_path *path = NULL;
793 char *name = NULL, *ptr;
794 u64 dirid;
795 int len;
796 int ret;
797
798 path = btrfs_alloc_path();
799 if (!path) {
800 ret = -ENOMEM;
801 goto err;
802 }
803
804 name = kmalloc(PATH_MAX, GFP_KERNEL);
805 if (!name) {
806 ret = -ENOMEM;
807 goto err;
808 }
809 ptr = name + PATH_MAX - 1;
810 ptr[0] = '\0';
811
812 /*
813 * Walk up the subvolume trees in the tree of tree roots by root
814 * backrefs until we hit the top-level subvolume.
815 */
816 while (subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
817 key.objectid = subvol_objectid;
818 key.type = BTRFS_ROOT_BACKREF_KEY;
819 key.offset = (u64)-1;
820
821 ret = btrfs_search_backwards(root, &key, path);
822 if (ret < 0) {
823 goto err;
824 } else if (ret > 0) {
825 ret = -ENOENT;
826 goto err;
827 }
828
829 subvol_objectid = key.offset;
830
831 root_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
832 struct btrfs_root_ref);
833 len = btrfs_root_ref_name_len(path->nodes[0], root_ref);
834 ptr -= len + 1;
835 if (ptr < name) {
836 ret = -ENAMETOOLONG;
837 goto err;
838 }
839 read_extent_buffer(path->nodes[0], ptr + 1,
840 (unsigned long)(root_ref + 1), len);
841 ptr[0] = '/';
842 dirid = btrfs_root_ref_dirid(path->nodes[0], root_ref);
843 btrfs_release_path(path);
844
845 fs_root = btrfs_get_fs_root(fs_info, subvol_objectid, true);
846 if (IS_ERR(fs_root)) {
847 ret = PTR_ERR(fs_root);
848 fs_root = NULL;
849 goto err;
850 }
851
852 /*
853 * Walk up the filesystem tree by inode refs until we hit the
854 * root directory.
855 */
856 while (dirid != BTRFS_FIRST_FREE_OBJECTID) {
857 key.objectid = dirid;
858 key.type = BTRFS_INODE_REF_KEY;
859 key.offset = (u64)-1;
860
861 ret = btrfs_search_backwards(fs_root, &key, path);
862 if (ret < 0) {
863 goto err;
864 } else if (ret > 0) {
865 ret = -ENOENT;
866 goto err;
867 }
868
869 dirid = key.offset;
870
871 inode_ref = btrfs_item_ptr(path->nodes[0],
872 path->slots[0],
873 struct btrfs_inode_ref);
874 len = btrfs_inode_ref_name_len(path->nodes[0],
875 inode_ref);
876 ptr -= len + 1;
877 if (ptr < name) {
878 ret = -ENAMETOOLONG;
879 goto err;
880 }
881 read_extent_buffer(path->nodes[0], ptr + 1,
882 (unsigned long)(inode_ref + 1), len);
883 ptr[0] = '/';
884 btrfs_release_path(path);
885 }
886 btrfs_put_root(fs_root);
887 fs_root = NULL;
888 }
889
890 btrfs_free_path(path);
891 if (ptr == name + PATH_MAX - 1) {
892 name[0] = '/';
893 name[1] = '\0';
894 } else {
895 memmove(name, ptr, name + PATH_MAX - ptr);
896 }
897 return name;
898
899err:
900 btrfs_put_root(fs_root);
901 btrfs_free_path(path);
902 kfree(name);
903 return ERR_PTR(ret);
904}
905
906static int get_default_subvol_objectid(struct btrfs_fs_info *fs_info, u64 *objectid)
907{
908 struct btrfs_root *root = fs_info->tree_root;
909 struct btrfs_dir_item *di;
910 struct btrfs_path *path;
911 struct btrfs_key location;
912 struct fscrypt_str name = FSTR_INIT("default", 7);
913 u64 dir_id;
914
915 path = btrfs_alloc_path();
916 if (!path)
917 return -ENOMEM;
918
919 /*
920 * Find the "default" dir item which points to the root item that we
921 * will mount by default if we haven't been given a specific subvolume
922 * to mount.
923 */
924 dir_id = btrfs_super_root_dir(fs_info->super_copy);
925 di = btrfs_lookup_dir_item(NULL, root, path, dir_id, &name, 0);
926 if (IS_ERR(di)) {
927 btrfs_free_path(path);
928 return PTR_ERR(di);
929 }
930 if (!di) {
931 /*
932 * Ok the default dir item isn't there. This is weird since
933 * it's always been there, but don't freak out, just try and
934 * mount the top-level subvolume.
935 */
936 btrfs_free_path(path);
937 *objectid = BTRFS_FS_TREE_OBJECTID;
938 return 0;
939 }
940
941 btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
942 btrfs_free_path(path);
943 *objectid = location.objectid;
944 return 0;
945}
946
947static int btrfs_fill_super(struct super_block *sb,
948 struct btrfs_fs_devices *fs_devices)
949{
950 struct inode *inode;
951 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
952 int err;
953
954 sb->s_maxbytes = MAX_LFS_FILESIZE;
955 sb->s_magic = BTRFS_SUPER_MAGIC;
956 sb->s_op = &btrfs_super_ops;
957 sb->s_d_op = &btrfs_dentry_operations;
958 sb->s_export_op = &btrfs_export_ops;
959#ifdef CONFIG_FS_VERITY
960 sb->s_vop = &btrfs_verityops;
961#endif
962 sb->s_xattr = btrfs_xattr_handlers;
963 sb->s_time_gran = 1;
964 sb->s_iflags |= SB_I_CGROUPWB;
965
966 err = super_setup_bdi(sb);
967 if (err) {
968 btrfs_err(fs_info, "super_setup_bdi failed");
969 return err;
970 }
971
972 err = open_ctree(sb, fs_devices);
973 if (err) {
974 btrfs_err(fs_info, "open_ctree failed: %d", err);
975 return err;
976 }
977
978 inode = btrfs_iget(BTRFS_FIRST_FREE_OBJECTID, fs_info->fs_root);
979 if (IS_ERR(inode)) {
980 err = PTR_ERR(inode);
981 btrfs_handle_fs_error(fs_info, err, NULL);
982 goto fail_close;
983 }
984
985 sb->s_root = d_make_root(inode);
986 if (!sb->s_root) {
987 err = -ENOMEM;
988 goto fail_close;
989 }
990
991 sb->s_flags |= SB_ACTIVE;
992 return 0;
993
994fail_close:
995 close_ctree(fs_info);
996 return err;
997}
998
999int btrfs_sync_fs(struct super_block *sb, int wait)
1000{
1001 struct btrfs_trans_handle *trans;
1002 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1003 struct btrfs_root *root = fs_info->tree_root;
1004
1005 trace_btrfs_sync_fs(fs_info, wait);
1006
1007 if (!wait) {
1008 filemap_flush(fs_info->btree_inode->i_mapping);
1009 return 0;
1010 }
1011
1012 btrfs_wait_ordered_roots(fs_info, U64_MAX, NULL);
1013
1014 trans = btrfs_attach_transaction_barrier(root);
1015 if (IS_ERR(trans)) {
1016 /* no transaction, don't bother */
1017 if (PTR_ERR(trans) == -ENOENT) {
1018 /*
1019 * Exit unless we have some pending changes
1020 * that need to go through commit
1021 */
1022 if (!test_bit(BTRFS_FS_NEED_TRANS_COMMIT,
1023 &fs_info->flags))
1024 return 0;
1025 /*
1026 * A non-blocking test if the fs is frozen. We must not
1027 * start a new transaction here otherwise a deadlock
1028 * happens. The pending operations are delayed to the
1029 * next commit after thawing.
1030 */
1031 if (sb_start_write_trylock(sb))
1032 sb_end_write(sb);
1033 else
1034 return 0;
1035 trans = btrfs_start_transaction(root, 0);
1036 }
1037 if (IS_ERR(trans))
1038 return PTR_ERR(trans);
1039 }
1040 return btrfs_commit_transaction(trans);
1041}
1042
1043static void print_rescue_option(struct seq_file *seq, const char *s, bool *printed)
1044{
1045 seq_printf(seq, "%s%s", (*printed) ? ":" : ",rescue=", s);
1046 *printed = true;
1047}
1048
1049static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
1050{
1051 struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
1052 const char *compress_type;
1053 const char *subvol_name;
1054 bool printed = false;
1055
1056 if (btrfs_test_opt(info, DEGRADED))
1057 seq_puts(seq, ",degraded");
1058 if (btrfs_test_opt(info, NODATASUM))
1059 seq_puts(seq, ",nodatasum");
1060 if (btrfs_test_opt(info, NODATACOW))
1061 seq_puts(seq, ",nodatacow");
1062 if (btrfs_test_opt(info, NOBARRIER))
1063 seq_puts(seq, ",nobarrier");
1064 if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE)
1065 seq_printf(seq, ",max_inline=%llu", info->max_inline);
1066 if (info->thread_pool_size != min_t(unsigned long,
1067 num_online_cpus() + 2, 8))
1068 seq_printf(seq, ",thread_pool=%u", info->thread_pool_size);
1069 if (btrfs_test_opt(info, COMPRESS)) {
1070 compress_type = btrfs_compress_type2str(info->compress_type);
1071 if (btrfs_test_opt(info, FORCE_COMPRESS))
1072 seq_printf(seq, ",compress-force=%s", compress_type);
1073 else
1074 seq_printf(seq, ",compress=%s", compress_type);
1075 if (info->compress_level)
1076 seq_printf(seq, ":%d", info->compress_level);
1077 }
1078 if (btrfs_test_opt(info, NOSSD))
1079 seq_puts(seq, ",nossd");
1080 if (btrfs_test_opt(info, SSD_SPREAD))
1081 seq_puts(seq, ",ssd_spread");
1082 else if (btrfs_test_opt(info, SSD))
1083 seq_puts(seq, ",ssd");
1084 if (btrfs_test_opt(info, NOTREELOG))
1085 seq_puts(seq, ",notreelog");
1086 if (btrfs_test_opt(info, NOLOGREPLAY))
1087 print_rescue_option(seq, "nologreplay", &printed);
1088 if (btrfs_test_opt(info, USEBACKUPROOT))
1089 print_rescue_option(seq, "usebackuproot", &printed);
1090 if (btrfs_test_opt(info, IGNOREBADROOTS))
1091 print_rescue_option(seq, "ignorebadroots", &printed);
1092 if (btrfs_test_opt(info, IGNOREDATACSUMS))
1093 print_rescue_option(seq, "ignoredatacsums", &printed);
1094 if (btrfs_test_opt(info, IGNOREMETACSUMS))
1095 print_rescue_option(seq, "ignoremetacsums", &printed);
1096 if (btrfs_test_opt(info, IGNORESUPERFLAGS))
1097 print_rescue_option(seq, "ignoresuperflags", &printed);
1098 if (btrfs_test_opt(info, FLUSHONCOMMIT))
1099 seq_puts(seq, ",flushoncommit");
1100 if (btrfs_test_opt(info, DISCARD_SYNC))
1101 seq_puts(seq, ",discard");
1102 if (btrfs_test_opt(info, DISCARD_ASYNC))
1103 seq_puts(seq, ",discard=async");
1104 if (!(info->sb->s_flags & SB_POSIXACL))
1105 seq_puts(seq, ",noacl");
1106 if (btrfs_free_space_cache_v1_active(info))
1107 seq_puts(seq, ",space_cache");
1108 else if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE))
1109 seq_puts(seq, ",space_cache=v2");
1110 else
1111 seq_puts(seq, ",nospace_cache");
1112 if (btrfs_test_opt(info, RESCAN_UUID_TREE))
1113 seq_puts(seq, ",rescan_uuid_tree");
1114 if (btrfs_test_opt(info, CLEAR_CACHE))
1115 seq_puts(seq, ",clear_cache");
1116 if (btrfs_test_opt(info, USER_SUBVOL_RM_ALLOWED))
1117 seq_puts(seq, ",user_subvol_rm_allowed");
1118 if (btrfs_test_opt(info, ENOSPC_DEBUG))
1119 seq_puts(seq, ",enospc_debug");
1120 if (btrfs_test_opt(info, AUTO_DEFRAG))
1121 seq_puts(seq, ",autodefrag");
1122 if (btrfs_test_opt(info, SKIP_BALANCE))
1123 seq_puts(seq, ",skip_balance");
1124 if (info->metadata_ratio)
1125 seq_printf(seq, ",metadata_ratio=%u", info->metadata_ratio);
1126 if (btrfs_test_opt(info, PANIC_ON_FATAL_ERROR))
1127 seq_puts(seq, ",fatal_errors=panic");
1128 if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL)
1129 seq_printf(seq, ",commit=%u", info->commit_interval);
1130#ifdef CONFIG_BTRFS_DEBUG
1131 if (btrfs_test_opt(info, FRAGMENT_DATA))
1132 seq_puts(seq, ",fragment=data");
1133 if (btrfs_test_opt(info, FRAGMENT_METADATA))
1134 seq_puts(seq, ",fragment=metadata");
1135#endif
1136 if (btrfs_test_opt(info, REF_VERIFY))
1137 seq_puts(seq, ",ref_verify");
1138 seq_printf(seq, ",subvolid=%llu", btrfs_root_id(BTRFS_I(d_inode(dentry))->root));
1139 subvol_name = btrfs_get_subvol_name_from_objectid(info,
1140 btrfs_root_id(BTRFS_I(d_inode(dentry))->root));
1141 if (!IS_ERR(subvol_name)) {
1142 seq_puts(seq, ",subvol=");
1143 seq_escape(seq, subvol_name, " \t\n\\");
1144 kfree(subvol_name);
1145 }
1146 return 0;
1147}
1148
1149/*
1150 * subvolumes are identified by ino 256
1151 */
1152static inline int is_subvolume_inode(struct inode *inode)
1153{
1154 if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
1155 return 1;
1156 return 0;
1157}
1158
1159static struct dentry *mount_subvol(const char *subvol_name, u64 subvol_objectid,
1160 struct vfsmount *mnt)
1161{
1162 struct dentry *root;
1163 int ret;
1164
1165 if (!subvol_name) {
1166 if (!subvol_objectid) {
1167 ret = get_default_subvol_objectid(btrfs_sb(mnt->mnt_sb),
1168 &subvol_objectid);
1169 if (ret) {
1170 root = ERR_PTR(ret);
1171 goto out;
1172 }
1173 }
1174 subvol_name = btrfs_get_subvol_name_from_objectid(
1175 btrfs_sb(mnt->mnt_sb), subvol_objectid);
1176 if (IS_ERR(subvol_name)) {
1177 root = ERR_CAST(subvol_name);
1178 subvol_name = NULL;
1179 goto out;
1180 }
1181
1182 }
1183
1184 root = mount_subtree(mnt, subvol_name);
1185 /* mount_subtree() drops our reference on the vfsmount. */
1186 mnt = NULL;
1187
1188 if (!IS_ERR(root)) {
1189 struct super_block *s = root->d_sb;
1190 struct btrfs_fs_info *fs_info = btrfs_sb(s);
1191 struct inode *root_inode = d_inode(root);
1192 u64 root_objectid = btrfs_root_id(BTRFS_I(root_inode)->root);
1193
1194 ret = 0;
1195 if (!is_subvolume_inode(root_inode)) {
1196 btrfs_err(fs_info, "'%s' is not a valid subvolume",
1197 subvol_name);
1198 ret = -EINVAL;
1199 }
1200 if (subvol_objectid && root_objectid != subvol_objectid) {
1201 /*
1202 * This will also catch a race condition where a
1203 * subvolume which was passed by ID is renamed and
1204 * another subvolume is renamed over the old location.
1205 */
1206 btrfs_err(fs_info,
1207 "subvol '%s' does not match subvolid %llu",
1208 subvol_name, subvol_objectid);
1209 ret = -EINVAL;
1210 }
1211 if (ret) {
1212 dput(root);
1213 root = ERR_PTR(ret);
1214 deactivate_locked_super(s);
1215 }
1216 }
1217
1218out:
1219 mntput(mnt);
1220 kfree(subvol_name);
1221 return root;
1222}
1223
1224static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
1225 u32 new_pool_size, u32 old_pool_size)
1226{
1227 if (new_pool_size == old_pool_size)
1228 return;
1229
1230 fs_info->thread_pool_size = new_pool_size;
1231
1232 btrfs_info(fs_info, "resize thread pool %d -> %d",
1233 old_pool_size, new_pool_size);
1234
1235 btrfs_workqueue_set_max(fs_info->workers, new_pool_size);
1236 btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size);
1237 btrfs_workqueue_set_max(fs_info->caching_workers, new_pool_size);
1238 workqueue_set_max_active(fs_info->endio_workers, new_pool_size);
1239 workqueue_set_max_active(fs_info->endio_meta_workers, new_pool_size);
1240 btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size);
1241 btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
1242 btrfs_workqueue_set_max(fs_info->delayed_workers, new_pool_size);
1243}
1244
1245static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info,
1246 unsigned long long old_opts, int flags)
1247{
1248 if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1249 (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1250 (flags & SB_RDONLY))) {
1251 /* wait for any defraggers to finish */
1252 wait_event(fs_info->transaction_wait,
1253 (atomic_read(&fs_info->defrag_running) == 0));
1254 if (flags & SB_RDONLY)
1255 sync_filesystem(fs_info->sb);
1256 }
1257}
1258
1259static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
1260 unsigned long long old_opts)
1261{
1262 const bool cache_opt = btrfs_test_opt(fs_info, SPACE_CACHE);
1263
1264 /*
1265 * We need to cleanup all defragable inodes if the autodefragment is
1266 * close or the filesystem is read only.
1267 */
1268 if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1269 (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) || sb_rdonly(fs_info->sb))) {
1270 btrfs_cleanup_defrag_inodes(fs_info);
1271 }
1272
1273 /* If we toggled discard async */
1274 if (!btrfs_raw_test_opt(old_opts, DISCARD_ASYNC) &&
1275 btrfs_test_opt(fs_info, DISCARD_ASYNC))
1276 btrfs_discard_resume(fs_info);
1277 else if (btrfs_raw_test_opt(old_opts, DISCARD_ASYNC) &&
1278 !btrfs_test_opt(fs_info, DISCARD_ASYNC))
1279 btrfs_discard_cleanup(fs_info);
1280
1281 /* If we toggled space cache */
1282 if (cache_opt != btrfs_free_space_cache_v1_active(fs_info))
1283 btrfs_set_free_space_cache_v1_active(fs_info, cache_opt);
1284}
1285
1286static int btrfs_remount_rw(struct btrfs_fs_info *fs_info)
1287{
1288 int ret;
1289
1290 if (BTRFS_FS_ERROR(fs_info)) {
1291 btrfs_err(fs_info,
1292 "remounting read-write after error is not allowed");
1293 return -EINVAL;
1294 }
1295
1296 if (fs_info->fs_devices->rw_devices == 0)
1297 return -EACCES;
1298
1299 if (!btrfs_check_rw_degradable(fs_info, NULL)) {
1300 btrfs_warn(fs_info,
1301 "too many missing devices, writable remount is not allowed");
1302 return -EACCES;
1303 }
1304
1305 if (btrfs_super_log_root(fs_info->super_copy) != 0) {
1306 btrfs_warn(fs_info,
1307 "mount required to replay tree-log, cannot remount read-write");
1308 return -EINVAL;
1309 }
1310
1311 /*
1312 * NOTE: when remounting with a change that does writes, don't put it
1313 * anywhere above this point, as we are not sure to be safe to write
1314 * until we pass the above checks.
1315 */
1316 ret = btrfs_start_pre_rw_mount(fs_info);
1317 if (ret)
1318 return ret;
1319
1320 btrfs_clear_sb_rdonly(fs_info->sb);
1321
1322 set_bit(BTRFS_FS_OPEN, &fs_info->flags);
1323
1324 /*
1325 * If we've gone from readonly -> read-write, we need to get our
1326 * sync/async discard lists in the right state.
1327 */
1328 btrfs_discard_resume(fs_info);
1329
1330 return 0;
1331}
1332
1333static int btrfs_remount_ro(struct btrfs_fs_info *fs_info)
1334{
1335 /*
1336 * This also happens on 'umount -rf' or on shutdown, when the
1337 * filesystem is busy.
1338 */
1339 cancel_work_sync(&fs_info->async_reclaim_work);
1340 cancel_work_sync(&fs_info->async_data_reclaim_work);
1341
1342 btrfs_discard_cleanup(fs_info);
1343
1344 /* Wait for the uuid_scan task to finish */
1345 down(&fs_info->uuid_tree_rescan_sem);
1346 /* Avoid complains from lockdep et al. */
1347 up(&fs_info->uuid_tree_rescan_sem);
1348
1349 btrfs_set_sb_rdonly(fs_info->sb);
1350
1351 /*
1352 * Setting SB_RDONLY will put the cleaner thread to sleep at the next
1353 * loop if it's already active. If it's already asleep, we'll leave
1354 * unused block groups on disk until we're mounted read-write again
1355 * unless we clean them up here.
1356 */
1357 btrfs_delete_unused_bgs(fs_info);
1358
1359 /*
1360 * The cleaner task could be already running before we set the flag
1361 * BTRFS_FS_STATE_RO (and SB_RDONLY in the superblock). We must make
1362 * sure that after we finish the remount, i.e. after we call
1363 * btrfs_commit_super(), the cleaner can no longer start a transaction
1364 * - either because it was dropping a dead root, running delayed iputs
1365 * or deleting an unused block group (the cleaner picked a block
1366 * group from the list of unused block groups before we were able to
1367 * in the previous call to btrfs_delete_unused_bgs()).
1368 */
1369 wait_on_bit(&fs_info->flags, BTRFS_FS_CLEANER_RUNNING, TASK_UNINTERRUPTIBLE);
1370
1371 /*
1372 * We've set the superblock to RO mode, so we might have made the
1373 * cleaner task sleep without running all pending delayed iputs. Go
1374 * through all the delayed iputs here, so that if an unmount happens
1375 * without remounting RW we don't end up at finishing close_ctree()
1376 * with a non-empty list of delayed iputs.
1377 */
1378 btrfs_run_delayed_iputs(fs_info);
1379
1380 btrfs_dev_replace_suspend_for_unmount(fs_info);
1381 btrfs_scrub_cancel(fs_info);
1382 btrfs_pause_balance(fs_info);
1383
1384 /*
1385 * Pause the qgroup rescan worker if it is running. We don't want it to
1386 * be still running after we are in RO mode, as after that, by the time
1387 * we unmount, it might have left a transaction open, so we would leak
1388 * the transaction and/or crash.
1389 */
1390 btrfs_qgroup_wait_for_completion(fs_info, false);
1391
1392 return btrfs_commit_super(fs_info);
1393}
1394
1395static void btrfs_ctx_to_info(struct btrfs_fs_info *fs_info, struct btrfs_fs_context *ctx)
1396{
1397 fs_info->max_inline = ctx->max_inline;
1398 fs_info->commit_interval = ctx->commit_interval;
1399 fs_info->metadata_ratio = ctx->metadata_ratio;
1400 fs_info->thread_pool_size = ctx->thread_pool_size;
1401 fs_info->mount_opt = ctx->mount_opt;
1402 fs_info->compress_type = ctx->compress_type;
1403 fs_info->compress_level = ctx->compress_level;
1404}
1405
1406static void btrfs_info_to_ctx(struct btrfs_fs_info *fs_info, struct btrfs_fs_context *ctx)
1407{
1408 ctx->max_inline = fs_info->max_inline;
1409 ctx->commit_interval = fs_info->commit_interval;
1410 ctx->metadata_ratio = fs_info->metadata_ratio;
1411 ctx->thread_pool_size = fs_info->thread_pool_size;
1412 ctx->mount_opt = fs_info->mount_opt;
1413 ctx->compress_type = fs_info->compress_type;
1414 ctx->compress_level = fs_info->compress_level;
1415}
1416
1417#define btrfs_info_if_set(fs_info, old_ctx, opt, fmt, args...) \
1418do { \
1419 if ((!old_ctx || !btrfs_raw_test_opt(old_ctx->mount_opt, opt)) && \
1420 btrfs_raw_test_opt(fs_info->mount_opt, opt)) \
1421 btrfs_info(fs_info, fmt, ##args); \
1422} while (0)
1423
1424#define btrfs_info_if_unset(fs_info, old_ctx, opt, fmt, args...) \
1425do { \
1426 if ((old_ctx && btrfs_raw_test_opt(old_ctx->mount_opt, opt)) && \
1427 !btrfs_raw_test_opt(fs_info->mount_opt, opt)) \
1428 btrfs_info(fs_info, fmt, ##args); \
1429} while (0)
1430
1431static void btrfs_emit_options(struct btrfs_fs_info *info,
1432 struct btrfs_fs_context *old)
1433{
1434 btrfs_info_if_set(info, old, NODATASUM, "setting nodatasum");
1435 btrfs_info_if_set(info, old, DEGRADED, "allowing degraded mounts");
1436 btrfs_info_if_set(info, old, NODATASUM, "setting nodatasum");
1437 btrfs_info_if_set(info, old, SSD, "enabling ssd optimizations");
1438 btrfs_info_if_set(info, old, SSD_SPREAD, "using spread ssd allocation scheme");
1439 btrfs_info_if_set(info, old, NOBARRIER, "turning off barriers");
1440 btrfs_info_if_set(info, old, NOTREELOG, "disabling tree log");
1441 btrfs_info_if_set(info, old, NOLOGREPLAY, "disabling log replay at mount time");
1442 btrfs_info_if_set(info, old, FLUSHONCOMMIT, "turning on flush-on-commit");
1443 btrfs_info_if_set(info, old, DISCARD_SYNC, "turning on sync discard");
1444 btrfs_info_if_set(info, old, DISCARD_ASYNC, "turning on async discard");
1445 btrfs_info_if_set(info, old, FREE_SPACE_TREE, "enabling free space tree");
1446 btrfs_info_if_set(info, old, SPACE_CACHE, "enabling disk space caching");
1447 btrfs_info_if_set(info, old, CLEAR_CACHE, "force clearing of disk cache");
1448 btrfs_info_if_set(info, old, AUTO_DEFRAG, "enabling auto defrag");
1449 btrfs_info_if_set(info, old, FRAGMENT_DATA, "fragmenting data");
1450 btrfs_info_if_set(info, old, FRAGMENT_METADATA, "fragmenting metadata");
1451 btrfs_info_if_set(info, old, REF_VERIFY, "doing ref verification");
1452 btrfs_info_if_set(info, old, USEBACKUPROOT, "trying to use backup root at mount time");
1453 btrfs_info_if_set(info, old, IGNOREBADROOTS, "ignoring bad roots");
1454 btrfs_info_if_set(info, old, IGNOREDATACSUMS, "ignoring data csums");
1455 btrfs_info_if_set(info, old, IGNOREMETACSUMS, "ignoring meta csums");
1456 btrfs_info_if_set(info, old, IGNORESUPERFLAGS, "ignoring unknown super block flags");
1457
1458 btrfs_info_if_unset(info, old, NODATACOW, "setting datacow");
1459 btrfs_info_if_unset(info, old, SSD, "not using ssd optimizations");
1460 btrfs_info_if_unset(info, old, SSD_SPREAD, "not using spread ssd allocation scheme");
1461 btrfs_info_if_unset(info, old, NOBARRIER, "turning off barriers");
1462 btrfs_info_if_unset(info, old, NOTREELOG, "enabling tree log");
1463 btrfs_info_if_unset(info, old, SPACE_CACHE, "disabling disk space caching");
1464 btrfs_info_if_unset(info, old, FREE_SPACE_TREE, "disabling free space tree");
1465 btrfs_info_if_unset(info, old, AUTO_DEFRAG, "disabling auto defrag");
1466 btrfs_info_if_unset(info, old, COMPRESS, "use no compression");
1467
1468 /* Did the compression settings change? */
1469 if (btrfs_test_opt(info, COMPRESS) &&
1470 (!old ||
1471 old->compress_type != info->compress_type ||
1472 old->compress_level != info->compress_level ||
1473 (!btrfs_raw_test_opt(old->mount_opt, FORCE_COMPRESS) &&
1474 btrfs_raw_test_opt(info->mount_opt, FORCE_COMPRESS)))) {
1475 const char *compress_type = btrfs_compress_type2str(info->compress_type);
1476
1477 btrfs_info(info, "%s %s compression, level %d",
1478 btrfs_test_opt(info, FORCE_COMPRESS) ? "force" : "use",
1479 compress_type, info->compress_level);
1480 }
1481
1482 if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE)
1483 btrfs_info(info, "max_inline set to %llu", info->max_inline);
1484}
1485
1486static int btrfs_reconfigure(struct fs_context *fc)
1487{
1488 struct super_block *sb = fc->root->d_sb;
1489 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1490 struct btrfs_fs_context *ctx = fc->fs_private;
1491 struct btrfs_fs_context old_ctx;
1492 int ret = 0;
1493 bool mount_reconfigure = (fc->s_fs_info != NULL);
1494
1495 btrfs_info_to_ctx(fs_info, &old_ctx);
1496
1497 /*
1498 * This is our "bind mount" trick, we don't want to allow the user to do
1499 * anything other than mount a different ro/rw and a different subvol,
1500 * all of the mount options should be maintained.
1501 */
1502 if (mount_reconfigure)
1503 ctx->mount_opt = old_ctx.mount_opt;
1504
1505 sync_filesystem(sb);
1506 set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1507
1508 if (!btrfs_check_options(fs_info, &ctx->mount_opt, fc->sb_flags))
1509 return -EINVAL;
1510
1511 ret = btrfs_check_features(fs_info, !(fc->sb_flags & SB_RDONLY));
1512 if (ret < 0)
1513 return ret;
1514
1515 btrfs_ctx_to_info(fs_info, ctx);
1516 btrfs_remount_begin(fs_info, old_ctx.mount_opt, fc->sb_flags);
1517 btrfs_resize_thread_pool(fs_info, fs_info->thread_pool_size,
1518 old_ctx.thread_pool_size);
1519
1520 if ((bool)btrfs_test_opt(fs_info, FREE_SPACE_TREE) !=
1521 (bool)btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE) &&
1522 (!sb_rdonly(sb) || (fc->sb_flags & SB_RDONLY))) {
1523 btrfs_warn(fs_info,
1524 "remount supports changing free space tree only from RO to RW");
1525 /* Make sure free space cache options match the state on disk. */
1526 if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE)) {
1527 btrfs_set_opt(fs_info->mount_opt, FREE_SPACE_TREE);
1528 btrfs_clear_opt(fs_info->mount_opt, SPACE_CACHE);
1529 }
1530 if (btrfs_free_space_cache_v1_active(fs_info)) {
1531 btrfs_clear_opt(fs_info->mount_opt, FREE_SPACE_TREE);
1532 btrfs_set_opt(fs_info->mount_opt, SPACE_CACHE);
1533 }
1534 }
1535
1536 ret = 0;
1537 if (!sb_rdonly(sb) && (fc->sb_flags & SB_RDONLY))
1538 ret = btrfs_remount_ro(fs_info);
1539 else if (sb_rdonly(sb) && !(fc->sb_flags & SB_RDONLY))
1540 ret = btrfs_remount_rw(fs_info);
1541 if (ret)
1542 goto restore;
1543
1544 /*
1545 * If we set the mask during the parameter parsing VFS would reject the
1546 * remount. Here we can set the mask and the value will be updated
1547 * appropriately.
1548 */
1549 if ((fc->sb_flags & SB_POSIXACL) != (sb->s_flags & SB_POSIXACL))
1550 fc->sb_flags_mask |= SB_POSIXACL;
1551
1552 btrfs_emit_options(fs_info, &old_ctx);
1553 wake_up_process(fs_info->transaction_kthread);
1554 btrfs_remount_cleanup(fs_info, old_ctx.mount_opt);
1555 btrfs_clear_oneshot_options(fs_info);
1556 clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1557
1558 return 0;
1559restore:
1560 btrfs_ctx_to_info(fs_info, &old_ctx);
1561 btrfs_remount_cleanup(fs_info, old_ctx.mount_opt);
1562 clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1563 return ret;
1564}
1565
1566/* Used to sort the devices by max_avail(descending sort) */
1567static int btrfs_cmp_device_free_bytes(const void *a, const void *b)
1568{
1569 const struct btrfs_device_info *dev_info1 = a;
1570 const struct btrfs_device_info *dev_info2 = b;
1571
1572 if (dev_info1->max_avail > dev_info2->max_avail)
1573 return -1;
1574 else if (dev_info1->max_avail < dev_info2->max_avail)
1575 return 1;
1576 return 0;
1577}
1578
1579/*
1580 * sort the devices by max_avail, in which max free extent size of each device
1581 * is stored.(Descending Sort)
1582 */
1583static inline void btrfs_descending_sort_devices(
1584 struct btrfs_device_info *devices,
1585 size_t nr_devices)
1586{
1587 sort(devices, nr_devices, sizeof(struct btrfs_device_info),
1588 btrfs_cmp_device_free_bytes, NULL);
1589}
1590
1591/*
1592 * The helper to calc the free space on the devices that can be used to store
1593 * file data.
1594 */
1595static inline int btrfs_calc_avail_data_space(struct btrfs_fs_info *fs_info,
1596 u64 *free_bytes)
1597{
1598 struct btrfs_device_info *devices_info;
1599 struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
1600 struct btrfs_device *device;
1601 u64 type;
1602 u64 avail_space;
1603 u64 min_stripe_size;
1604 int num_stripes = 1;
1605 int i = 0, nr_devices;
1606 const struct btrfs_raid_attr *rattr;
1607
1608 /*
1609 * We aren't under the device list lock, so this is racy-ish, but good
1610 * enough for our purposes.
1611 */
1612 nr_devices = fs_info->fs_devices->open_devices;
1613 if (!nr_devices) {
1614 smp_mb();
1615 nr_devices = fs_info->fs_devices->open_devices;
1616 ASSERT(nr_devices);
1617 if (!nr_devices) {
1618 *free_bytes = 0;
1619 return 0;
1620 }
1621 }
1622
1623 devices_info = kmalloc_array(nr_devices, sizeof(*devices_info),
1624 GFP_KERNEL);
1625 if (!devices_info)
1626 return -ENOMEM;
1627
1628 /* calc min stripe number for data space allocation */
1629 type = btrfs_data_alloc_profile(fs_info);
1630 rattr = &btrfs_raid_array[btrfs_bg_flags_to_raid_index(type)];
1631
1632 if (type & BTRFS_BLOCK_GROUP_RAID0)
1633 num_stripes = nr_devices;
1634 else if (type & BTRFS_BLOCK_GROUP_RAID1_MASK)
1635 num_stripes = rattr->ncopies;
1636 else if (type & BTRFS_BLOCK_GROUP_RAID10)
1637 num_stripes = 4;
1638
1639 /* Adjust for more than 1 stripe per device */
1640 min_stripe_size = rattr->dev_stripes * BTRFS_STRIPE_LEN;
1641
1642 rcu_read_lock();
1643 list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
1644 if (!test_bit(BTRFS_DEV_STATE_IN_FS_METADATA,
1645 &device->dev_state) ||
1646 !device->bdev ||
1647 test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state))
1648 continue;
1649
1650 if (i >= nr_devices)
1651 break;
1652
1653 avail_space = device->total_bytes - device->bytes_used;
1654
1655 /* align with stripe_len */
1656 avail_space = rounddown(avail_space, BTRFS_STRIPE_LEN);
1657
1658 /*
1659 * Ensure we have at least min_stripe_size on top of the
1660 * reserved space on the device.
1661 */
1662 if (avail_space <= BTRFS_DEVICE_RANGE_RESERVED + min_stripe_size)
1663 continue;
1664
1665 avail_space -= BTRFS_DEVICE_RANGE_RESERVED;
1666
1667 devices_info[i].dev = device;
1668 devices_info[i].max_avail = avail_space;
1669
1670 i++;
1671 }
1672 rcu_read_unlock();
1673
1674 nr_devices = i;
1675
1676 btrfs_descending_sort_devices(devices_info, nr_devices);
1677
1678 i = nr_devices - 1;
1679 avail_space = 0;
1680 while (nr_devices >= rattr->devs_min) {
1681 num_stripes = min(num_stripes, nr_devices);
1682
1683 if (devices_info[i].max_avail >= min_stripe_size) {
1684 int j;
1685 u64 alloc_size;
1686
1687 avail_space += devices_info[i].max_avail * num_stripes;
1688 alloc_size = devices_info[i].max_avail;
1689 for (j = i + 1 - num_stripes; j <= i; j++)
1690 devices_info[j].max_avail -= alloc_size;
1691 }
1692 i--;
1693 nr_devices--;
1694 }
1695
1696 kfree(devices_info);
1697 *free_bytes = avail_space;
1698 return 0;
1699}
1700
1701/*
1702 * Calculate numbers for 'df', pessimistic in case of mixed raid profiles.
1703 *
1704 * If there's a redundant raid level at DATA block groups, use the respective
1705 * multiplier to scale the sizes.
1706 *
1707 * Unused device space usage is based on simulating the chunk allocator
1708 * algorithm that respects the device sizes and order of allocations. This is
1709 * a close approximation of the actual use but there are other factors that may
1710 * change the result (like a new metadata chunk).
1711 *
1712 * If metadata is exhausted, f_bavail will be 0.
1713 */
1714static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
1715{
1716 struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
1717 struct btrfs_super_block *disk_super = fs_info->super_copy;
1718 struct btrfs_space_info *found;
1719 u64 total_used = 0;
1720 u64 total_free_data = 0;
1721 u64 total_free_meta = 0;
1722 u32 bits = fs_info->sectorsize_bits;
1723 __be32 *fsid = (__be32 *)fs_info->fs_devices->fsid;
1724 unsigned factor = 1;
1725 struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
1726 int ret;
1727 u64 thresh = 0;
1728 int mixed = 0;
1729
1730 list_for_each_entry(found, &fs_info->space_info, list) {
1731 if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
1732 int i;
1733
1734 total_free_data += found->disk_total - found->disk_used;
1735 total_free_data -=
1736 btrfs_account_ro_block_groups_free_space(found);
1737
1738 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
1739 if (!list_empty(&found->block_groups[i]))
1740 factor = btrfs_bg_type_to_factor(
1741 btrfs_raid_array[i].bg_flag);
1742 }
1743 }
1744
1745 /*
1746 * Metadata in mixed block group profiles are accounted in data
1747 */
1748 if (!mixed && found->flags & BTRFS_BLOCK_GROUP_METADATA) {
1749 if (found->flags & BTRFS_BLOCK_GROUP_DATA)
1750 mixed = 1;
1751 else
1752 total_free_meta += found->disk_total -
1753 found->disk_used;
1754 }
1755
1756 total_used += found->disk_used;
1757 }
1758
1759 buf->f_blocks = div_u64(btrfs_super_total_bytes(disk_super), factor);
1760 buf->f_blocks >>= bits;
1761 buf->f_bfree = buf->f_blocks - (div_u64(total_used, factor) >> bits);
1762
1763 /* Account global block reserve as used, it's in logical size already */
1764 spin_lock(&block_rsv->lock);
1765 /* Mixed block groups accounting is not byte-accurate, avoid overflow */
1766 if (buf->f_bfree >= block_rsv->size >> bits)
1767 buf->f_bfree -= block_rsv->size >> bits;
1768 else
1769 buf->f_bfree = 0;
1770 spin_unlock(&block_rsv->lock);
1771
1772 buf->f_bavail = div_u64(total_free_data, factor);
1773 ret = btrfs_calc_avail_data_space(fs_info, &total_free_data);
1774 if (ret)
1775 return ret;
1776 buf->f_bavail += div_u64(total_free_data, factor);
1777 buf->f_bavail = buf->f_bavail >> bits;
1778
1779 /*
1780 * We calculate the remaining metadata space minus global reserve. If
1781 * this is (supposedly) smaller than zero, there's no space. But this
1782 * does not hold in practice, the exhausted state happens where's still
1783 * some positive delta. So we apply some guesswork and compare the
1784 * delta to a 4M threshold. (Practically observed delta was ~2M.)
1785 *
1786 * We probably cannot calculate the exact threshold value because this
1787 * depends on the internal reservations requested by various
1788 * operations, so some operations that consume a few metadata will
1789 * succeed even if the Avail is zero. But this is better than the other
1790 * way around.
1791 */
1792 thresh = SZ_4M;
1793
1794 /*
1795 * We only want to claim there's no available space if we can no longer
1796 * allocate chunks for our metadata profile and our global reserve will
1797 * not fit in the free metadata space. If we aren't ->full then we
1798 * still can allocate chunks and thus are fine using the currently
1799 * calculated f_bavail.
1800 */
1801 if (!mixed && block_rsv->space_info->full &&
1802 (total_free_meta < thresh || total_free_meta - thresh < block_rsv->size))
1803 buf->f_bavail = 0;
1804
1805 buf->f_type = BTRFS_SUPER_MAGIC;
1806 buf->f_bsize = fs_info->sectorsize;
1807 buf->f_namelen = BTRFS_NAME_LEN;
1808
1809 /* We treat it as constant endianness (it doesn't matter _which_)
1810 because we want the fsid to come out the same whether mounted
1811 on a big-endian or little-endian host */
1812 buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
1813 buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
1814 /* Mask in the root object ID too, to disambiguate subvols */
1815 buf->f_fsid.val[0] ^= btrfs_root_id(BTRFS_I(d_inode(dentry))->root) >> 32;
1816 buf->f_fsid.val[1] ^= btrfs_root_id(BTRFS_I(d_inode(dentry))->root);
1817
1818 return 0;
1819}
1820
1821static int btrfs_fc_test_super(struct super_block *sb, struct fs_context *fc)
1822{
1823 struct btrfs_fs_info *p = fc->s_fs_info;
1824 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1825
1826 return fs_info->fs_devices == p->fs_devices;
1827}
1828
1829static int btrfs_get_tree_super(struct fs_context *fc)
1830{
1831 struct btrfs_fs_info *fs_info = fc->s_fs_info;
1832 struct btrfs_fs_context *ctx = fc->fs_private;
1833 struct btrfs_fs_devices *fs_devices = NULL;
1834 struct block_device *bdev;
1835 struct btrfs_device *device;
1836 struct super_block *sb;
1837 blk_mode_t mode = btrfs_open_mode(fc);
1838 int ret;
1839
1840 btrfs_ctx_to_info(fs_info, ctx);
1841 mutex_lock(&uuid_mutex);
1842
1843 /*
1844 * With 'true' passed to btrfs_scan_one_device() (mount time) we expect
1845 * either a valid device or an error.
1846 */
1847 device = btrfs_scan_one_device(fc->source, mode, true);
1848 ASSERT(device != NULL);
1849 if (IS_ERR(device)) {
1850 mutex_unlock(&uuid_mutex);
1851 return PTR_ERR(device);
1852 }
1853
1854 fs_devices = device->fs_devices;
1855 fs_info->fs_devices = fs_devices;
1856
1857 ret = btrfs_open_devices(fs_devices, mode, &btrfs_fs_type);
1858 mutex_unlock(&uuid_mutex);
1859 if (ret)
1860 return ret;
1861
1862 if (!(fc->sb_flags & SB_RDONLY) && fs_devices->rw_devices == 0) {
1863 ret = -EACCES;
1864 goto error;
1865 }
1866
1867 bdev = fs_devices->latest_dev->bdev;
1868
1869 /*
1870 * From now on the error handling is not straightforward.
1871 *
1872 * If successful, this will transfer the fs_info into the super block,
1873 * and fc->s_fs_info will be NULL. However if there's an existing
1874 * super, we'll still have fc->s_fs_info populated. If we error
1875 * completely out it'll be cleaned up when we drop the fs_context,
1876 * otherwise it's tied to the lifetime of the super_block.
1877 */
1878 sb = sget_fc(fc, btrfs_fc_test_super, set_anon_super_fc);
1879 if (IS_ERR(sb)) {
1880 ret = PTR_ERR(sb);
1881 goto error;
1882 }
1883
1884 set_device_specific_options(fs_info);
1885
1886 if (sb->s_root) {
1887 btrfs_close_devices(fs_devices);
1888 /*
1889 * At this stage we may have RO flag mismatch between
1890 * fc->sb_flags and sb->s_flags. Caller should detect such
1891 * mismatch and reconfigure with sb->s_umount rwsem held if
1892 * needed.
1893 */
1894 } else {
1895 snprintf(sb->s_id, sizeof(sb->s_id), "%pg", bdev);
1896 shrinker_debugfs_rename(sb->s_shrink, "sb-btrfs:%s", sb->s_id);
1897 btrfs_sb(sb)->bdev_holder = &btrfs_fs_type;
1898 ret = btrfs_fill_super(sb, fs_devices);
1899 if (ret) {
1900 deactivate_locked_super(sb);
1901 return ret;
1902 }
1903 }
1904
1905 btrfs_clear_oneshot_options(fs_info);
1906
1907 fc->root = dget(sb->s_root);
1908 return 0;
1909
1910error:
1911 btrfs_close_devices(fs_devices);
1912 return ret;
1913}
1914
1915/*
1916 * Ever since commit 0723a0473fb4 ("btrfs: allow mounting btrfs subvolumes
1917 * with different ro/rw options") the following works:
1918 *
1919 * (i) mount /dev/sda3 -o subvol=foo,ro /mnt/foo
1920 * (ii) mount /dev/sda3 -o subvol=bar,rw /mnt/bar
1921 *
1922 * which looks nice and innocent but is actually pretty intricate and deserves
1923 * a long comment.
1924 *
1925 * On another filesystem a subvolume mount is close to something like:
1926 *
1927 * (iii) # create rw superblock + initial mount
1928 * mount -t xfs /dev/sdb /opt/
1929 *
1930 * # create ro bind mount
1931 * mount --bind -o ro /opt/foo /mnt/foo
1932 *
1933 * # unmount initial mount
1934 * umount /opt
1935 *
1936 * Of course, there's some special subvolume sauce and there's the fact that the
1937 * sb->s_root dentry is really swapped after mount_subtree(). But conceptually
1938 * it's very close and will help us understand the issue.
1939 *
1940 * The old mount API didn't cleanly distinguish between a mount being made ro
1941 * and a superblock being made ro. The only way to change the ro state of
1942 * either object was by passing ms_rdonly. If a new mount was created via
1943 * mount(2) such as:
1944 *
1945 * mount("/dev/sdb", "/mnt", "xfs", ms_rdonly, null);
1946 *
1947 * the MS_RDONLY flag being specified had two effects:
1948 *
1949 * (1) MNT_READONLY was raised -> the resulting mount got
1950 * @mnt->mnt_flags |= MNT_READONLY raised.
1951 *
1952 * (2) MS_RDONLY was passed to the filesystem's mount method and the filesystems
1953 * made the superblock ro. Note, how SB_RDONLY has the same value as
1954 * ms_rdonly and is raised whenever MS_RDONLY is passed through mount(2).
1955 *
1956 * Creating a subtree mount via (iii) ends up leaving a rw superblock with a
1957 * subtree mounted ro.
1958 *
1959 * But consider the effect on the old mount API on btrfs subvolume mounting
1960 * which combines the distinct step in (iii) into a single step.
1961 *
1962 * By issuing (i) both the mount and the superblock are turned ro. Now when (ii)
1963 * is issued the superblock is ro and thus even if the mount created for (ii) is
1964 * rw it wouldn't help. Hence, btrfs needed to transition the superblock from ro
1965 * to rw for (ii) which it did using an internal remount call.
1966 *
1967 * IOW, subvolume mounting was inherently complicated due to the ambiguity of
1968 * MS_RDONLY in mount(2). Note, this ambiguity has mount(8) always translate
1969 * "ro" to MS_RDONLY. IOW, in both (i) and (ii) "ro" becomes MS_RDONLY when
1970 * passed by mount(8) to mount(2).
1971 *
1972 * Enter the new mount API. The new mount API disambiguates making a mount ro
1973 * and making a superblock ro.
1974 *
1975 * (3) To turn a mount ro the MOUNT_ATTR_ONLY flag can be used with either
1976 * fsmount() or mount_setattr() this is a pure VFS level change for a
1977 * specific mount or mount tree that is never seen by the filesystem itself.
1978 *
1979 * (4) To turn a superblock ro the "ro" flag must be used with
1980 * fsconfig(FSCONFIG_SET_FLAG, "ro"). This option is seen by the filesystem
1981 * in fc->sb_flags.
1982 *
1983 * But, currently the util-linux mount command already utilizes the new mount
1984 * API and is still setting fsconfig(FSCONFIG_SET_FLAG, "ro") no matter if it's
1985 * btrfs or not, setting the whole super block RO. To make per-subvolume mounting
1986 * work with different options work we need to keep backward compatibility.
1987 */
1988static int btrfs_reconfigure_for_mount(struct fs_context *fc, struct vfsmount *mnt)
1989{
1990 int ret = 0;
1991
1992 if (fc->sb_flags & SB_RDONLY)
1993 return ret;
1994
1995 down_write(&mnt->mnt_sb->s_umount);
1996 if (!(fc->sb_flags & SB_RDONLY) && (mnt->mnt_sb->s_flags & SB_RDONLY))
1997 ret = btrfs_reconfigure(fc);
1998 up_write(&mnt->mnt_sb->s_umount);
1999 return ret;
2000}
2001
2002static int btrfs_get_tree_subvol(struct fs_context *fc)
2003{
2004 struct btrfs_fs_info *fs_info = NULL;
2005 struct btrfs_fs_context *ctx = fc->fs_private;
2006 struct fs_context *dup_fc;
2007 struct dentry *dentry;
2008 struct vfsmount *mnt;
2009 int ret = 0;
2010
2011 /*
2012 * Setup a dummy root and fs_info for test/set super. This is because
2013 * we don't actually fill this stuff out until open_ctree, but we need
2014 * then open_ctree will properly initialize the file system specific
2015 * settings later. btrfs_init_fs_info initializes the static elements
2016 * of the fs_info (locks and such) to make cleanup easier if we find a
2017 * superblock with our given fs_devices later on at sget() time.
2018 */
2019 fs_info = kvzalloc(sizeof(struct btrfs_fs_info), GFP_KERNEL);
2020 if (!fs_info)
2021 return -ENOMEM;
2022
2023 fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
2024 fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
2025 if (!fs_info->super_copy || !fs_info->super_for_commit) {
2026 btrfs_free_fs_info(fs_info);
2027 return -ENOMEM;
2028 }
2029 btrfs_init_fs_info(fs_info);
2030
2031 dup_fc = vfs_dup_fs_context(fc);
2032 if (IS_ERR(dup_fc)) {
2033 btrfs_free_fs_info(fs_info);
2034 return PTR_ERR(dup_fc);
2035 }
2036
2037 /*
2038 * When we do the sget_fc this gets transferred to the sb, so we only
2039 * need to set it on the dup_fc as this is what creates the super block.
2040 */
2041 dup_fc->s_fs_info = fs_info;
2042
2043 /*
2044 * We'll do the security settings in our btrfs_get_tree_super() mount
2045 * loop, they were duplicated into dup_fc, we can drop the originals
2046 * here.
2047 */
2048 security_free_mnt_opts(&fc->security);
2049 fc->security = NULL;
2050
2051 mnt = fc_mount(dup_fc);
2052 if (IS_ERR(mnt)) {
2053 put_fs_context(dup_fc);
2054 return PTR_ERR(mnt);
2055 }
2056 ret = btrfs_reconfigure_for_mount(dup_fc, mnt);
2057 put_fs_context(dup_fc);
2058 if (ret) {
2059 mntput(mnt);
2060 return ret;
2061 }
2062
2063 /*
2064 * This free's ->subvol_name, because if it isn't set we have to
2065 * allocate a buffer to hold the subvol_name, so we just drop our
2066 * reference to it here.
2067 */
2068 dentry = mount_subvol(ctx->subvol_name, ctx->subvol_objectid, mnt);
2069 ctx->subvol_name = NULL;
2070 if (IS_ERR(dentry))
2071 return PTR_ERR(dentry);
2072
2073 fc->root = dentry;
2074 return 0;
2075}
2076
2077static int btrfs_get_tree(struct fs_context *fc)
2078{
2079 /*
2080 * Since we use mount_subtree to mount the default/specified subvol, we
2081 * have to do mounts in two steps.
2082 *
2083 * First pass through we call btrfs_get_tree_subvol(), this is just a
2084 * wrapper around fc_mount() to call back into here again, and this time
2085 * we'll call btrfs_get_tree_super(). This will do the open_ctree() and
2086 * everything to open the devices and file system. Then we return back
2087 * with a fully constructed vfsmount in btrfs_get_tree_subvol(), and
2088 * from there we can do our mount_subvol() call, which will lookup
2089 * whichever subvol we're mounting and setup this fc with the
2090 * appropriate dentry for the subvol.
2091 */
2092 if (fc->s_fs_info)
2093 return btrfs_get_tree_super(fc);
2094 return btrfs_get_tree_subvol(fc);
2095}
2096
2097static void btrfs_kill_super(struct super_block *sb)
2098{
2099 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2100 kill_anon_super(sb);
2101 btrfs_free_fs_info(fs_info);
2102}
2103
2104static void btrfs_free_fs_context(struct fs_context *fc)
2105{
2106 struct btrfs_fs_context *ctx = fc->fs_private;
2107 struct btrfs_fs_info *fs_info = fc->s_fs_info;
2108
2109 if (fs_info)
2110 btrfs_free_fs_info(fs_info);
2111
2112 if (ctx && refcount_dec_and_test(&ctx->refs)) {
2113 kfree(ctx->subvol_name);
2114 kfree(ctx);
2115 }
2116}
2117
2118static int btrfs_dup_fs_context(struct fs_context *fc, struct fs_context *src_fc)
2119{
2120 struct btrfs_fs_context *ctx = src_fc->fs_private;
2121
2122 /*
2123 * Give a ref to our ctx to this dup, as we want to keep it around for
2124 * our original fc so we can have the subvolume name or objectid.
2125 *
2126 * We unset ->source in the original fc because the dup needs it for
2127 * mounting, and then once we free the dup it'll free ->source, so we
2128 * need to make sure we're only pointing to it in one fc.
2129 */
2130 refcount_inc(&ctx->refs);
2131 fc->fs_private = ctx;
2132 fc->source = src_fc->source;
2133 src_fc->source = NULL;
2134 return 0;
2135}
2136
2137static const struct fs_context_operations btrfs_fs_context_ops = {
2138 .parse_param = btrfs_parse_param,
2139 .reconfigure = btrfs_reconfigure,
2140 .get_tree = btrfs_get_tree,
2141 .dup = btrfs_dup_fs_context,
2142 .free = btrfs_free_fs_context,
2143};
2144
2145static int btrfs_init_fs_context(struct fs_context *fc)
2146{
2147 struct btrfs_fs_context *ctx;
2148
2149 ctx = kzalloc(sizeof(struct btrfs_fs_context), GFP_KERNEL);
2150 if (!ctx)
2151 return -ENOMEM;
2152
2153 refcount_set(&ctx->refs, 1);
2154 fc->fs_private = ctx;
2155 fc->ops = &btrfs_fs_context_ops;
2156
2157 if (fc->purpose == FS_CONTEXT_FOR_RECONFIGURE) {
2158 btrfs_info_to_ctx(btrfs_sb(fc->root->d_sb), ctx);
2159 } else {
2160 ctx->thread_pool_size =
2161 min_t(unsigned long, num_online_cpus() + 2, 8);
2162 ctx->max_inline = BTRFS_DEFAULT_MAX_INLINE;
2163 ctx->commit_interval = BTRFS_DEFAULT_COMMIT_INTERVAL;
2164 }
2165
2166#ifdef CONFIG_BTRFS_FS_POSIX_ACL
2167 fc->sb_flags |= SB_POSIXACL;
2168#endif
2169 fc->sb_flags |= SB_I_VERSION;
2170
2171 return 0;
2172}
2173
2174static struct file_system_type btrfs_fs_type = {
2175 .owner = THIS_MODULE,
2176 .name = "btrfs",
2177 .init_fs_context = btrfs_init_fs_context,
2178 .parameters = btrfs_fs_parameters,
2179 .kill_sb = btrfs_kill_super,
2180 .fs_flags = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA |
2181 FS_ALLOW_IDMAP | FS_MGTIME,
2182 };
2183
2184MODULE_ALIAS_FS("btrfs");
2185
2186static int btrfs_control_open(struct inode *inode, struct file *file)
2187{
2188 /*
2189 * The control file's private_data is used to hold the
2190 * transaction when it is started and is used to keep
2191 * track of whether a transaction is already in progress.
2192 */
2193 file->private_data = NULL;
2194 return 0;
2195}
2196
2197/*
2198 * Used by /dev/btrfs-control for devices ioctls.
2199 */
2200static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
2201 unsigned long arg)
2202{
2203 struct btrfs_ioctl_vol_args *vol;
2204 struct btrfs_device *device = NULL;
2205 dev_t devt = 0;
2206 int ret = -ENOTTY;
2207
2208 if (!capable(CAP_SYS_ADMIN))
2209 return -EPERM;
2210
2211 vol = memdup_user((void __user *)arg, sizeof(*vol));
2212 if (IS_ERR(vol))
2213 return PTR_ERR(vol);
2214 ret = btrfs_check_ioctl_vol_args_path(vol);
2215 if (ret < 0)
2216 goto out;
2217
2218 switch (cmd) {
2219 case BTRFS_IOC_SCAN_DEV:
2220 mutex_lock(&uuid_mutex);
2221 /*
2222 * Scanning outside of mount can return NULL which would turn
2223 * into 0 error code.
2224 */
2225 device = btrfs_scan_one_device(vol->name, BLK_OPEN_READ, false);
2226 ret = PTR_ERR_OR_ZERO(device);
2227 mutex_unlock(&uuid_mutex);
2228 break;
2229 case BTRFS_IOC_FORGET_DEV:
2230 if (vol->name[0] != 0) {
2231 ret = lookup_bdev(vol->name, &devt);
2232 if (ret)
2233 break;
2234 }
2235 ret = btrfs_forget_devices(devt);
2236 break;
2237 case BTRFS_IOC_DEVICES_READY:
2238 mutex_lock(&uuid_mutex);
2239 /*
2240 * Scanning outside of mount can return NULL which would turn
2241 * into 0 error code.
2242 */
2243 device = btrfs_scan_one_device(vol->name, BLK_OPEN_READ, false);
2244 if (IS_ERR_OR_NULL(device)) {
2245 mutex_unlock(&uuid_mutex);
2246 if (IS_ERR(device))
2247 ret = PTR_ERR(device);
2248 else
2249 ret = 0;
2250 break;
2251 }
2252 ret = !(device->fs_devices->num_devices ==
2253 device->fs_devices->total_devices);
2254 mutex_unlock(&uuid_mutex);
2255 break;
2256 case BTRFS_IOC_GET_SUPPORTED_FEATURES:
2257 ret = btrfs_ioctl_get_supported_features((void __user*)arg);
2258 break;
2259 }
2260
2261out:
2262 kfree(vol);
2263 return ret;
2264}
2265
2266static int btrfs_freeze(struct super_block *sb)
2267{
2268 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2269
2270 set_bit(BTRFS_FS_FROZEN, &fs_info->flags);
2271 /*
2272 * We don't need a barrier here, we'll wait for any transaction that
2273 * could be in progress on other threads (and do delayed iputs that
2274 * we want to avoid on a frozen filesystem), or do the commit
2275 * ourselves.
2276 */
2277 return btrfs_commit_current_transaction(fs_info->tree_root);
2278}
2279
2280static int check_dev_super(struct btrfs_device *dev)
2281{
2282 struct btrfs_fs_info *fs_info = dev->fs_info;
2283 struct btrfs_super_block *sb;
2284 u64 last_trans;
2285 u16 csum_type;
2286 int ret = 0;
2287
2288 /* This should be called with fs still frozen. */
2289 ASSERT(test_bit(BTRFS_FS_FROZEN, &fs_info->flags));
2290
2291 /* Missing dev, no need to check. */
2292 if (!dev->bdev)
2293 return 0;
2294
2295 /* Only need to check the primary super block. */
2296 sb = btrfs_read_dev_one_super(dev->bdev, 0, true);
2297 if (IS_ERR(sb))
2298 return PTR_ERR(sb);
2299
2300 /* Verify the checksum. */
2301 csum_type = btrfs_super_csum_type(sb);
2302 if (csum_type != btrfs_super_csum_type(fs_info->super_copy)) {
2303 btrfs_err(fs_info, "csum type changed, has %u expect %u",
2304 csum_type, btrfs_super_csum_type(fs_info->super_copy));
2305 ret = -EUCLEAN;
2306 goto out;
2307 }
2308
2309 if (btrfs_check_super_csum(fs_info, sb)) {
2310 btrfs_err(fs_info, "csum for on-disk super block no longer matches");
2311 ret = -EUCLEAN;
2312 goto out;
2313 }
2314
2315 /* Btrfs_validate_super() includes fsid check against super->fsid. */
2316 ret = btrfs_validate_super(fs_info, sb, 0);
2317 if (ret < 0)
2318 goto out;
2319
2320 last_trans = btrfs_get_last_trans_committed(fs_info);
2321 if (btrfs_super_generation(sb) != last_trans) {
2322 btrfs_err(fs_info, "transid mismatch, has %llu expect %llu",
2323 btrfs_super_generation(sb), last_trans);
2324 ret = -EUCLEAN;
2325 goto out;
2326 }
2327out:
2328 btrfs_release_disk_super(sb);
2329 return ret;
2330}
2331
2332static int btrfs_unfreeze(struct super_block *sb)
2333{
2334 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2335 struct btrfs_device *device;
2336 int ret = 0;
2337
2338 /*
2339 * Make sure the fs is not changed by accident (like hibernation then
2340 * modified by other OS).
2341 * If we found anything wrong, we mark the fs error immediately.
2342 *
2343 * And since the fs is frozen, no one can modify the fs yet, thus
2344 * we don't need to hold device_list_mutex.
2345 */
2346 list_for_each_entry(device, &fs_info->fs_devices->devices, dev_list) {
2347 ret = check_dev_super(device);
2348 if (ret < 0) {
2349 btrfs_handle_fs_error(fs_info, ret,
2350 "super block on devid %llu got modified unexpectedly",
2351 device->devid);
2352 break;
2353 }
2354 }
2355 clear_bit(BTRFS_FS_FROZEN, &fs_info->flags);
2356
2357 /*
2358 * We still return 0, to allow VFS layer to unfreeze the fs even the
2359 * above checks failed. Since the fs is either fine or read-only, we're
2360 * safe to continue, without causing further damage.
2361 */
2362 return 0;
2363}
2364
2365static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
2366{
2367 struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
2368
2369 /*
2370 * There should be always a valid pointer in latest_dev, it may be stale
2371 * for a short moment in case it's being deleted but still valid until
2372 * the end of RCU grace period.
2373 */
2374 rcu_read_lock();
2375 seq_escape(m, btrfs_dev_name(fs_info->fs_devices->latest_dev), " \t\n\\");
2376 rcu_read_unlock();
2377
2378 return 0;
2379}
2380
2381static long btrfs_nr_cached_objects(struct super_block *sb, struct shrink_control *sc)
2382{
2383 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2384 const s64 nr = percpu_counter_sum_positive(&fs_info->evictable_extent_maps);
2385
2386 trace_btrfs_extent_map_shrinker_count(fs_info, nr);
2387
2388 return nr;
2389}
2390
2391static long btrfs_free_cached_objects(struct super_block *sb, struct shrink_control *sc)
2392{
2393 const long nr_to_scan = min_t(unsigned long, LONG_MAX, sc->nr_to_scan);
2394 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2395
2396 btrfs_free_extent_maps(fs_info, nr_to_scan);
2397
2398 /* The extent map shrinker runs asynchronously, so always return 0. */
2399 return 0;
2400}
2401
2402static const struct super_operations btrfs_super_ops = {
2403 .drop_inode = btrfs_drop_inode,
2404 .evict_inode = btrfs_evict_inode,
2405 .put_super = btrfs_put_super,
2406 .sync_fs = btrfs_sync_fs,
2407 .show_options = btrfs_show_options,
2408 .show_devname = btrfs_show_devname,
2409 .alloc_inode = btrfs_alloc_inode,
2410 .destroy_inode = btrfs_destroy_inode,
2411 .free_inode = btrfs_free_inode,
2412 .statfs = btrfs_statfs,
2413 .freeze_fs = btrfs_freeze,
2414 .unfreeze_fs = btrfs_unfreeze,
2415 .nr_cached_objects = btrfs_nr_cached_objects,
2416 .free_cached_objects = btrfs_free_cached_objects,
2417};
2418
2419static const struct file_operations btrfs_ctl_fops = {
2420 .open = btrfs_control_open,
2421 .unlocked_ioctl = btrfs_control_ioctl,
2422 .compat_ioctl = compat_ptr_ioctl,
2423 .owner = THIS_MODULE,
2424 .llseek = noop_llseek,
2425};
2426
2427static struct miscdevice btrfs_misc = {
2428 .minor = BTRFS_MINOR,
2429 .name = "btrfs-control",
2430 .fops = &btrfs_ctl_fops
2431};
2432
2433MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
2434MODULE_ALIAS("devname:btrfs-control");
2435
2436static int __init btrfs_interface_init(void)
2437{
2438 return misc_register(&btrfs_misc);
2439}
2440
2441static __cold void btrfs_interface_exit(void)
2442{
2443 misc_deregister(&btrfs_misc);
2444}
2445
2446static int __init btrfs_print_mod_info(void)
2447{
2448 static const char options[] = ""
2449#ifdef CONFIG_BTRFS_DEBUG
2450 ", debug=on"
2451#endif
2452#ifdef CONFIG_BTRFS_ASSERT
2453 ", assert=on"
2454#endif
2455#ifdef CONFIG_BTRFS_FS_REF_VERIFY
2456 ", ref-verify=on"
2457#endif
2458#ifdef CONFIG_BLK_DEV_ZONED
2459 ", zoned=yes"
2460#else
2461 ", zoned=no"
2462#endif
2463#ifdef CONFIG_FS_VERITY
2464 ", fsverity=yes"
2465#else
2466 ", fsverity=no"
2467#endif
2468 ;
2469 pr_info("Btrfs loaded%s\n", options);
2470 return 0;
2471}
2472
2473static int register_btrfs(void)
2474{
2475 return register_filesystem(&btrfs_fs_type);
2476}
2477
2478static void unregister_btrfs(void)
2479{
2480 unregister_filesystem(&btrfs_fs_type);
2481}
2482
2483/* Helper structure for long init/exit functions. */
2484struct init_sequence {
2485 int (*init_func)(void);
2486 /* Can be NULL if the init_func doesn't need cleanup. */
2487 void (*exit_func)(void);
2488};
2489
2490static const struct init_sequence mod_init_seq[] = {
2491 {
2492 .init_func = btrfs_props_init,
2493 .exit_func = NULL,
2494 }, {
2495 .init_func = btrfs_init_sysfs,
2496 .exit_func = btrfs_exit_sysfs,
2497 }, {
2498 .init_func = btrfs_init_compress,
2499 .exit_func = btrfs_exit_compress,
2500 }, {
2501 .init_func = btrfs_init_cachep,
2502 .exit_func = btrfs_destroy_cachep,
2503 }, {
2504 .init_func = btrfs_init_dio,
2505 .exit_func = btrfs_destroy_dio,
2506 }, {
2507 .init_func = btrfs_transaction_init,
2508 .exit_func = btrfs_transaction_exit,
2509 }, {
2510 .init_func = btrfs_ctree_init,
2511 .exit_func = btrfs_ctree_exit,
2512 }, {
2513 .init_func = btrfs_free_space_init,
2514 .exit_func = btrfs_free_space_exit,
2515 }, {
2516 .init_func = extent_state_init_cachep,
2517 .exit_func = extent_state_free_cachep,
2518 }, {
2519 .init_func = extent_buffer_init_cachep,
2520 .exit_func = extent_buffer_free_cachep,
2521 }, {
2522 .init_func = btrfs_bioset_init,
2523 .exit_func = btrfs_bioset_exit,
2524 }, {
2525 .init_func = extent_map_init,
2526 .exit_func = extent_map_exit,
2527 }, {
2528 .init_func = ordered_data_init,
2529 .exit_func = ordered_data_exit,
2530 }, {
2531 .init_func = btrfs_delayed_inode_init,
2532 .exit_func = btrfs_delayed_inode_exit,
2533 }, {
2534 .init_func = btrfs_auto_defrag_init,
2535 .exit_func = btrfs_auto_defrag_exit,
2536 }, {
2537 .init_func = btrfs_delayed_ref_init,
2538 .exit_func = btrfs_delayed_ref_exit,
2539 }, {
2540 .init_func = btrfs_prelim_ref_init,
2541 .exit_func = btrfs_prelim_ref_exit,
2542 }, {
2543 .init_func = btrfs_interface_init,
2544 .exit_func = btrfs_interface_exit,
2545 }, {
2546 .init_func = btrfs_print_mod_info,
2547 .exit_func = NULL,
2548 }, {
2549 .init_func = btrfs_run_sanity_tests,
2550 .exit_func = NULL,
2551 }, {
2552 .init_func = register_btrfs,
2553 .exit_func = unregister_btrfs,
2554 }
2555};
2556
2557static bool mod_init_result[ARRAY_SIZE(mod_init_seq)];
2558
2559static __always_inline void btrfs_exit_btrfs_fs(void)
2560{
2561 int i;
2562
2563 for (i = ARRAY_SIZE(mod_init_seq) - 1; i >= 0; i--) {
2564 if (!mod_init_result[i])
2565 continue;
2566 if (mod_init_seq[i].exit_func)
2567 mod_init_seq[i].exit_func();
2568 mod_init_result[i] = false;
2569 }
2570}
2571
2572static void __exit exit_btrfs_fs(void)
2573{
2574 btrfs_exit_btrfs_fs();
2575 btrfs_cleanup_fs_uuids();
2576}
2577
2578static int __init init_btrfs_fs(void)
2579{
2580 int ret;
2581 int i;
2582
2583 for (i = 0; i < ARRAY_SIZE(mod_init_seq); i++) {
2584 ASSERT(!mod_init_result[i]);
2585 ret = mod_init_seq[i].init_func();
2586 if (ret < 0) {
2587 btrfs_exit_btrfs_fs();
2588 return ret;
2589 }
2590 mod_init_result[i] = true;
2591 }
2592 return 0;
2593}
2594
2595late_initcall(init_btrfs_fs);
2596module_exit(exit_btrfs_fs)
2597
2598MODULE_DESCRIPTION("B-Tree File System (BTRFS)");
2599MODULE_LICENSE("GPL");
2600MODULE_SOFTDEP("pre: crc32c");
2601MODULE_SOFTDEP("pre: xxhash64");
2602MODULE_SOFTDEP("pre: sha256");
2603MODULE_SOFTDEP("pre: blake2b-256");
1/*
2 * Copyright (C) 2007 Oracle. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18
19#include <linux/blkdev.h>
20#include <linux/module.h>
21#include <linux/buffer_head.h>
22#include <linux/fs.h>
23#include <linux/pagemap.h>
24#include <linux/highmem.h>
25#include <linux/time.h>
26#include <linux/init.h>
27#include <linux/seq_file.h>
28#include <linux/string.h>
29#include <linux/backing-dev.h>
30#include <linux/mount.h>
31#include <linux/mpage.h>
32#include <linux/swap.h>
33#include <linux/writeback.h>
34#include <linux/statfs.h>
35#include <linux/compat.h>
36#include <linux/parser.h>
37#include <linux/ctype.h>
38#include <linux/namei.h>
39#include <linux/miscdevice.h>
40#include <linux/magic.h>
41#include <linux/slab.h>
42#include <linux/cleancache.h>
43#include <linux/ratelimit.h>
44#include <linux/btrfs.h>
45#include "delayed-inode.h"
46#include "ctree.h"
47#include "disk-io.h"
48#include "transaction.h"
49#include "btrfs_inode.h"
50#include "print-tree.h"
51#include "hash.h"
52#include "props.h"
53#include "xattr.h"
54#include "volumes.h"
55#include "export.h"
56#include "compression.h"
57#include "rcu-string.h"
58#include "dev-replace.h"
59#include "free-space-cache.h"
60#include "backref.h"
61#include "tests/btrfs-tests.h"
62
63#include "qgroup.h"
64#define CREATE_TRACE_POINTS
65#include <trace/events/btrfs.h>
66
67static const struct super_operations btrfs_super_ops;
68static struct file_system_type btrfs_fs_type;
69
70static int btrfs_remount(struct super_block *sb, int *flags, char *data);
71
72const char *btrfs_decode_error(int errno)
73{
74 char *errstr = "unknown";
75
76 switch (errno) {
77 case -EIO:
78 errstr = "IO failure";
79 break;
80 case -ENOMEM:
81 errstr = "Out of memory";
82 break;
83 case -EROFS:
84 errstr = "Readonly filesystem";
85 break;
86 case -EEXIST:
87 errstr = "Object already exists";
88 break;
89 case -ENOSPC:
90 errstr = "No space left";
91 break;
92 case -ENOENT:
93 errstr = "No such entry";
94 break;
95 }
96
97 return errstr;
98}
99
100static void save_error_info(struct btrfs_fs_info *fs_info)
101{
102 /*
103 * today we only save the error info into ram. Long term we'll
104 * also send it down to the disk
105 */
106 set_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state);
107}
108
109/* btrfs handle error by forcing the filesystem readonly */
110static void btrfs_handle_error(struct btrfs_fs_info *fs_info)
111{
112 struct super_block *sb = fs_info->sb;
113
114 if (sb->s_flags & MS_RDONLY)
115 return;
116
117 if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
118 sb->s_flags |= MS_RDONLY;
119 btrfs_info(fs_info, "forced readonly");
120 /*
121 * Note that a running device replace operation is not
122 * canceled here although there is no way to update
123 * the progress. It would add the risk of a deadlock,
124 * therefore the canceling is ommited. The only penalty
125 * is that some I/O remains active until the procedure
126 * completes. The next time when the filesystem is
127 * mounted writeable again, the device replace
128 * operation continues.
129 */
130 }
131}
132
133/*
134 * __btrfs_std_error decodes expected errors from the caller and
135 * invokes the approciate error response.
136 */
137__cold
138void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function,
139 unsigned int line, int errno, const char *fmt, ...)
140{
141 struct super_block *sb = fs_info->sb;
142#ifdef CONFIG_PRINTK
143 const char *errstr;
144#endif
145
146 /*
147 * Special case: if the error is EROFS, and we're already
148 * under MS_RDONLY, then it is safe here.
149 */
150 if (errno == -EROFS && (sb->s_flags & MS_RDONLY))
151 return;
152
153#ifdef CONFIG_PRINTK
154 errstr = btrfs_decode_error(errno);
155 if (fmt) {
156 struct va_format vaf;
157 va_list args;
158
159 va_start(args, fmt);
160 vaf.fmt = fmt;
161 vaf.va = &args;
162
163 printk(KERN_CRIT
164 "BTRFS: error (device %s) in %s:%d: errno=%d %s (%pV)\n",
165 sb->s_id, function, line, errno, errstr, &vaf);
166 va_end(args);
167 } else {
168 printk(KERN_CRIT "BTRFS: error (device %s) in %s:%d: errno=%d %s\n",
169 sb->s_id, function, line, errno, errstr);
170 }
171#endif
172
173 /* Don't go through full error handling during mount */
174 save_error_info(fs_info);
175 if (sb->s_flags & MS_BORN)
176 btrfs_handle_error(fs_info);
177}
178
179#ifdef CONFIG_PRINTK
180static const char * const logtypes[] = {
181 "emergency",
182 "alert",
183 "critical",
184 "error",
185 "warning",
186 "notice",
187 "info",
188 "debug",
189};
190
191void btrfs_printk(const struct btrfs_fs_info *fs_info, const char *fmt, ...)
192{
193 struct super_block *sb = fs_info->sb;
194 char lvl[4];
195 struct va_format vaf;
196 va_list args;
197 const char *type = logtypes[4];
198 int kern_level;
199
200 va_start(args, fmt);
201
202 kern_level = printk_get_level(fmt);
203 if (kern_level) {
204 size_t size = printk_skip_level(fmt) - fmt;
205 memcpy(lvl, fmt, size);
206 lvl[size] = '\0';
207 fmt += size;
208 type = logtypes[kern_level - '0'];
209 } else
210 *lvl = '\0';
211
212 vaf.fmt = fmt;
213 vaf.va = &args;
214
215 printk("%sBTRFS %s (device %s): %pV\n", lvl, type, sb->s_id, &vaf);
216
217 va_end(args);
218}
219#endif
220
221/*
222 * We only mark the transaction aborted and then set the file system read-only.
223 * This will prevent new transactions from starting or trying to join this
224 * one.
225 *
226 * This means that error recovery at the call site is limited to freeing
227 * any local memory allocations and passing the error code up without
228 * further cleanup. The transaction should complete as it normally would
229 * in the call path but will return -EIO.
230 *
231 * We'll complete the cleanup in btrfs_end_transaction and
232 * btrfs_commit_transaction.
233 */
234__cold
235void __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
236 struct btrfs_root *root, const char *function,
237 unsigned int line, int errno)
238{
239 trans->aborted = errno;
240 /* Nothing used. The other threads that have joined this
241 * transaction may be able to continue. */
242 if (!trans->blocks_used && list_empty(&trans->new_bgs)) {
243 const char *errstr;
244
245 errstr = btrfs_decode_error(errno);
246 btrfs_warn(root->fs_info,
247 "%s:%d: Aborting unused transaction(%s).",
248 function, line, errstr);
249 return;
250 }
251 ACCESS_ONCE(trans->transaction->aborted) = errno;
252 /* Wake up anybody who may be waiting on this transaction */
253 wake_up(&root->fs_info->transaction_wait);
254 wake_up(&root->fs_info->transaction_blocked_wait);
255 __btrfs_std_error(root->fs_info, function, line, errno, NULL);
256}
257/*
258 * __btrfs_panic decodes unexpected, fatal errors from the caller,
259 * issues an alert, and either panics or BUGs, depending on mount options.
260 */
261__cold
262void __btrfs_panic(struct btrfs_fs_info *fs_info, const char *function,
263 unsigned int line, int errno, const char *fmt, ...)
264{
265 char *s_id = "<unknown>";
266 const char *errstr;
267 struct va_format vaf = { .fmt = fmt };
268 va_list args;
269
270 if (fs_info)
271 s_id = fs_info->sb->s_id;
272
273 va_start(args, fmt);
274 vaf.va = &args;
275
276 errstr = btrfs_decode_error(errno);
277 if (fs_info && (fs_info->mount_opt & BTRFS_MOUNT_PANIC_ON_FATAL_ERROR))
278 panic(KERN_CRIT "BTRFS panic (device %s) in %s:%d: %pV (errno=%d %s)\n",
279 s_id, function, line, &vaf, errno, errstr);
280
281 btrfs_crit(fs_info, "panic in %s:%d: %pV (errno=%d %s)",
282 function, line, &vaf, errno, errstr);
283 va_end(args);
284 /* Caller calls BUG() */
285}
286
287static void btrfs_put_super(struct super_block *sb)
288{
289 close_ctree(btrfs_sb(sb)->tree_root);
290}
291
292enum {
293 Opt_degraded, Opt_subvol, Opt_subvolid, Opt_device, Opt_nodatasum,
294 Opt_nodatacow, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd,
295 Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl, Opt_compress,
296 Opt_compress_type, Opt_compress_force, Opt_compress_force_type,
297 Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard,
298 Opt_space_cache, Opt_space_cache_version, Opt_clear_cache,
299 Opt_user_subvol_rm_allowed, Opt_enospc_debug, Opt_subvolrootid,
300 Opt_defrag, Opt_inode_cache, Opt_no_space_cache, Opt_recovery,
301 Opt_skip_balance, Opt_check_integrity,
302 Opt_check_integrity_including_extent_data,
303 Opt_check_integrity_print_mask, Opt_fatal_errors, Opt_rescan_uuid_tree,
304 Opt_commit_interval, Opt_barrier, Opt_nodefrag, Opt_nodiscard,
305 Opt_noenospc_debug, Opt_noflushoncommit, Opt_acl, Opt_datacow,
306 Opt_datasum, Opt_treelog, Opt_noinode_cache, Opt_usebackuproot,
307 Opt_nologreplay, Opt_norecovery,
308#ifdef CONFIG_BTRFS_DEBUG
309 Opt_fragment_data, Opt_fragment_metadata, Opt_fragment_all,
310#endif
311 Opt_err,
312};
313
314static const match_table_t tokens = {
315 {Opt_degraded, "degraded"},
316 {Opt_subvol, "subvol=%s"},
317 {Opt_subvolid, "subvolid=%s"},
318 {Opt_device, "device=%s"},
319 {Opt_nodatasum, "nodatasum"},
320 {Opt_datasum, "datasum"},
321 {Opt_nodatacow, "nodatacow"},
322 {Opt_datacow, "datacow"},
323 {Opt_nobarrier, "nobarrier"},
324 {Opt_barrier, "barrier"},
325 {Opt_max_inline, "max_inline=%s"},
326 {Opt_alloc_start, "alloc_start=%s"},
327 {Opt_thread_pool, "thread_pool=%d"},
328 {Opt_compress, "compress"},
329 {Opt_compress_type, "compress=%s"},
330 {Opt_compress_force, "compress-force"},
331 {Opt_compress_force_type, "compress-force=%s"},
332 {Opt_ssd, "ssd"},
333 {Opt_ssd_spread, "ssd_spread"},
334 {Opt_nossd, "nossd"},
335 {Opt_acl, "acl"},
336 {Opt_noacl, "noacl"},
337 {Opt_notreelog, "notreelog"},
338 {Opt_treelog, "treelog"},
339 {Opt_nologreplay, "nologreplay"},
340 {Opt_norecovery, "norecovery"},
341 {Opt_flushoncommit, "flushoncommit"},
342 {Opt_noflushoncommit, "noflushoncommit"},
343 {Opt_ratio, "metadata_ratio=%d"},
344 {Opt_discard, "discard"},
345 {Opt_nodiscard, "nodiscard"},
346 {Opt_space_cache, "space_cache"},
347 {Opt_space_cache_version, "space_cache=%s"},
348 {Opt_clear_cache, "clear_cache"},
349 {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
350 {Opt_enospc_debug, "enospc_debug"},
351 {Opt_noenospc_debug, "noenospc_debug"},
352 {Opt_subvolrootid, "subvolrootid=%d"},
353 {Opt_defrag, "autodefrag"},
354 {Opt_nodefrag, "noautodefrag"},
355 {Opt_inode_cache, "inode_cache"},
356 {Opt_noinode_cache, "noinode_cache"},
357 {Opt_no_space_cache, "nospace_cache"},
358 {Opt_recovery, "recovery"}, /* deprecated */
359 {Opt_usebackuproot, "usebackuproot"},
360 {Opt_skip_balance, "skip_balance"},
361 {Opt_check_integrity, "check_int"},
362 {Opt_check_integrity_including_extent_data, "check_int_data"},
363 {Opt_check_integrity_print_mask, "check_int_print_mask=%d"},
364 {Opt_rescan_uuid_tree, "rescan_uuid_tree"},
365 {Opt_fatal_errors, "fatal_errors=%s"},
366 {Opt_commit_interval, "commit=%d"},
367#ifdef CONFIG_BTRFS_DEBUG
368 {Opt_fragment_data, "fragment=data"},
369 {Opt_fragment_metadata, "fragment=metadata"},
370 {Opt_fragment_all, "fragment=all"},
371#endif
372 {Opt_err, NULL},
373};
374
375/*
376 * Regular mount options parser. Everything that is needed only when
377 * reading in a new superblock is parsed here.
378 * XXX JDM: This needs to be cleaned up for remount.
379 */
380int btrfs_parse_options(struct btrfs_root *root, char *options,
381 unsigned long new_flags)
382{
383 struct btrfs_fs_info *info = root->fs_info;
384 substring_t args[MAX_OPT_ARGS];
385 char *p, *num, *orig = NULL;
386 u64 cache_gen;
387 int intarg;
388 int ret = 0;
389 char *compress_type;
390 bool compress_force = false;
391 enum btrfs_compression_type saved_compress_type;
392 bool saved_compress_force;
393 int no_compress = 0;
394
395 cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
396 if (btrfs_fs_compat_ro(root->fs_info, FREE_SPACE_TREE))
397 btrfs_set_opt(info->mount_opt, FREE_SPACE_TREE);
398 else if (cache_gen)
399 btrfs_set_opt(info->mount_opt, SPACE_CACHE);
400
401 /*
402 * Even the options are empty, we still need to do extra check
403 * against new flags
404 */
405 if (!options)
406 goto check;
407
408 /*
409 * strsep changes the string, duplicate it because parse_options
410 * gets called twice
411 */
412 options = kstrdup(options, GFP_NOFS);
413 if (!options)
414 return -ENOMEM;
415
416 orig = options;
417
418 while ((p = strsep(&options, ",")) != NULL) {
419 int token;
420 if (!*p)
421 continue;
422
423 token = match_token(p, tokens, args);
424 switch (token) {
425 case Opt_degraded:
426 btrfs_info(root->fs_info, "allowing degraded mounts");
427 btrfs_set_opt(info->mount_opt, DEGRADED);
428 break;
429 case Opt_subvol:
430 case Opt_subvolid:
431 case Opt_subvolrootid:
432 case Opt_device:
433 /*
434 * These are parsed by btrfs_parse_early_options
435 * and can be happily ignored here.
436 */
437 break;
438 case Opt_nodatasum:
439 btrfs_set_and_info(root, NODATASUM,
440 "setting nodatasum");
441 break;
442 case Opt_datasum:
443 if (btrfs_test_opt(root, NODATASUM)) {
444 if (btrfs_test_opt(root, NODATACOW))
445 btrfs_info(root->fs_info, "setting datasum, datacow enabled");
446 else
447 btrfs_info(root->fs_info, "setting datasum");
448 }
449 btrfs_clear_opt(info->mount_opt, NODATACOW);
450 btrfs_clear_opt(info->mount_opt, NODATASUM);
451 break;
452 case Opt_nodatacow:
453 if (!btrfs_test_opt(root, NODATACOW)) {
454 if (!btrfs_test_opt(root, COMPRESS) ||
455 !btrfs_test_opt(root, FORCE_COMPRESS)) {
456 btrfs_info(root->fs_info,
457 "setting nodatacow, compression disabled");
458 } else {
459 btrfs_info(root->fs_info, "setting nodatacow");
460 }
461 }
462 btrfs_clear_opt(info->mount_opt, COMPRESS);
463 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
464 btrfs_set_opt(info->mount_opt, NODATACOW);
465 btrfs_set_opt(info->mount_opt, NODATASUM);
466 break;
467 case Opt_datacow:
468 btrfs_clear_and_info(root, NODATACOW,
469 "setting datacow");
470 break;
471 case Opt_compress_force:
472 case Opt_compress_force_type:
473 compress_force = true;
474 /* Fallthrough */
475 case Opt_compress:
476 case Opt_compress_type:
477 saved_compress_type = btrfs_test_opt(root, COMPRESS) ?
478 info->compress_type : BTRFS_COMPRESS_NONE;
479 saved_compress_force =
480 btrfs_test_opt(root, FORCE_COMPRESS);
481 if (token == Opt_compress ||
482 token == Opt_compress_force ||
483 strcmp(args[0].from, "zlib") == 0) {
484 compress_type = "zlib";
485 info->compress_type = BTRFS_COMPRESS_ZLIB;
486 btrfs_set_opt(info->mount_opt, COMPRESS);
487 btrfs_clear_opt(info->mount_opt, NODATACOW);
488 btrfs_clear_opt(info->mount_opt, NODATASUM);
489 no_compress = 0;
490 } else if (strcmp(args[0].from, "lzo") == 0) {
491 compress_type = "lzo";
492 info->compress_type = BTRFS_COMPRESS_LZO;
493 btrfs_set_opt(info->mount_opt, COMPRESS);
494 btrfs_clear_opt(info->mount_opt, NODATACOW);
495 btrfs_clear_opt(info->mount_opt, NODATASUM);
496 btrfs_set_fs_incompat(info, COMPRESS_LZO);
497 no_compress = 0;
498 } else if (strncmp(args[0].from, "no", 2) == 0) {
499 compress_type = "no";
500 btrfs_clear_opt(info->mount_opt, COMPRESS);
501 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
502 compress_force = false;
503 no_compress++;
504 } else {
505 ret = -EINVAL;
506 goto out;
507 }
508
509 if (compress_force) {
510 btrfs_set_opt(info->mount_opt, FORCE_COMPRESS);
511 } else {
512 /*
513 * If we remount from compress-force=xxx to
514 * compress=xxx, we need clear FORCE_COMPRESS
515 * flag, otherwise, there is no way for users
516 * to disable forcible compression separately.
517 */
518 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
519 }
520 if ((btrfs_test_opt(root, COMPRESS) &&
521 (info->compress_type != saved_compress_type ||
522 compress_force != saved_compress_force)) ||
523 (!btrfs_test_opt(root, COMPRESS) &&
524 no_compress == 1)) {
525 btrfs_info(root->fs_info,
526 "%s %s compression",
527 (compress_force) ? "force" : "use",
528 compress_type);
529 }
530 compress_force = false;
531 break;
532 case Opt_ssd:
533 btrfs_set_and_info(root, SSD,
534 "use ssd allocation scheme");
535 break;
536 case Opt_ssd_spread:
537 btrfs_set_and_info(root, SSD_SPREAD,
538 "use spread ssd allocation scheme");
539 btrfs_set_opt(info->mount_opt, SSD);
540 break;
541 case Opt_nossd:
542 btrfs_set_and_info(root, NOSSD,
543 "not using ssd allocation scheme");
544 btrfs_clear_opt(info->mount_opt, SSD);
545 break;
546 case Opt_barrier:
547 btrfs_clear_and_info(root, NOBARRIER,
548 "turning on barriers");
549 break;
550 case Opt_nobarrier:
551 btrfs_set_and_info(root, NOBARRIER,
552 "turning off barriers");
553 break;
554 case Opt_thread_pool:
555 ret = match_int(&args[0], &intarg);
556 if (ret) {
557 goto out;
558 } else if (intarg > 0) {
559 info->thread_pool_size = intarg;
560 } else {
561 ret = -EINVAL;
562 goto out;
563 }
564 break;
565 case Opt_max_inline:
566 num = match_strdup(&args[0]);
567 if (num) {
568 info->max_inline = memparse(num, NULL);
569 kfree(num);
570
571 if (info->max_inline) {
572 info->max_inline = min_t(u64,
573 info->max_inline,
574 root->sectorsize);
575 }
576 btrfs_info(root->fs_info, "max_inline at %llu",
577 info->max_inline);
578 } else {
579 ret = -ENOMEM;
580 goto out;
581 }
582 break;
583 case Opt_alloc_start:
584 num = match_strdup(&args[0]);
585 if (num) {
586 mutex_lock(&info->chunk_mutex);
587 info->alloc_start = memparse(num, NULL);
588 mutex_unlock(&info->chunk_mutex);
589 kfree(num);
590 btrfs_info(root->fs_info, "allocations start at %llu",
591 info->alloc_start);
592 } else {
593 ret = -ENOMEM;
594 goto out;
595 }
596 break;
597 case Opt_acl:
598#ifdef CONFIG_BTRFS_FS_POSIX_ACL
599 root->fs_info->sb->s_flags |= MS_POSIXACL;
600 break;
601#else
602 btrfs_err(root->fs_info,
603 "support for ACL not compiled in!");
604 ret = -EINVAL;
605 goto out;
606#endif
607 case Opt_noacl:
608 root->fs_info->sb->s_flags &= ~MS_POSIXACL;
609 break;
610 case Opt_notreelog:
611 btrfs_set_and_info(root, NOTREELOG,
612 "disabling tree log");
613 break;
614 case Opt_treelog:
615 btrfs_clear_and_info(root, NOTREELOG,
616 "enabling tree log");
617 break;
618 case Opt_norecovery:
619 case Opt_nologreplay:
620 btrfs_set_and_info(root, NOLOGREPLAY,
621 "disabling log replay at mount time");
622 break;
623 case Opt_flushoncommit:
624 btrfs_set_and_info(root, FLUSHONCOMMIT,
625 "turning on flush-on-commit");
626 break;
627 case Opt_noflushoncommit:
628 btrfs_clear_and_info(root, FLUSHONCOMMIT,
629 "turning off flush-on-commit");
630 break;
631 case Opt_ratio:
632 ret = match_int(&args[0], &intarg);
633 if (ret) {
634 goto out;
635 } else if (intarg >= 0) {
636 info->metadata_ratio = intarg;
637 btrfs_info(root->fs_info, "metadata ratio %d",
638 info->metadata_ratio);
639 } else {
640 ret = -EINVAL;
641 goto out;
642 }
643 break;
644 case Opt_discard:
645 btrfs_set_and_info(root, DISCARD,
646 "turning on discard");
647 break;
648 case Opt_nodiscard:
649 btrfs_clear_and_info(root, DISCARD,
650 "turning off discard");
651 break;
652 case Opt_space_cache:
653 case Opt_space_cache_version:
654 if (token == Opt_space_cache ||
655 strcmp(args[0].from, "v1") == 0) {
656 btrfs_clear_opt(root->fs_info->mount_opt,
657 FREE_SPACE_TREE);
658 btrfs_set_and_info(root, SPACE_CACHE,
659 "enabling disk space caching");
660 } else if (strcmp(args[0].from, "v2") == 0) {
661 btrfs_clear_opt(root->fs_info->mount_opt,
662 SPACE_CACHE);
663 btrfs_set_and_info(root, FREE_SPACE_TREE,
664 "enabling free space tree");
665 } else {
666 ret = -EINVAL;
667 goto out;
668 }
669 break;
670 case Opt_rescan_uuid_tree:
671 btrfs_set_opt(info->mount_opt, RESCAN_UUID_TREE);
672 break;
673 case Opt_no_space_cache:
674 if (btrfs_test_opt(root, SPACE_CACHE)) {
675 btrfs_clear_and_info(root, SPACE_CACHE,
676 "disabling disk space caching");
677 }
678 if (btrfs_test_opt(root, FREE_SPACE_TREE)) {
679 btrfs_clear_and_info(root, FREE_SPACE_TREE,
680 "disabling free space tree");
681 }
682 break;
683 case Opt_inode_cache:
684 btrfs_set_pending_and_info(info, INODE_MAP_CACHE,
685 "enabling inode map caching");
686 break;
687 case Opt_noinode_cache:
688 btrfs_clear_pending_and_info(info, INODE_MAP_CACHE,
689 "disabling inode map caching");
690 break;
691 case Opt_clear_cache:
692 btrfs_set_and_info(root, CLEAR_CACHE,
693 "force clearing of disk cache");
694 break;
695 case Opt_user_subvol_rm_allowed:
696 btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
697 break;
698 case Opt_enospc_debug:
699 btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
700 break;
701 case Opt_noenospc_debug:
702 btrfs_clear_opt(info->mount_opt, ENOSPC_DEBUG);
703 break;
704 case Opt_defrag:
705 btrfs_set_and_info(root, AUTO_DEFRAG,
706 "enabling auto defrag");
707 break;
708 case Opt_nodefrag:
709 btrfs_clear_and_info(root, AUTO_DEFRAG,
710 "disabling auto defrag");
711 break;
712 case Opt_recovery:
713 btrfs_warn(root->fs_info,
714 "'recovery' is deprecated, use 'usebackuproot' instead");
715 case Opt_usebackuproot:
716 btrfs_info(root->fs_info,
717 "trying to use backup root at mount time");
718 btrfs_set_opt(info->mount_opt, USEBACKUPROOT);
719 break;
720 case Opt_skip_balance:
721 btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
722 break;
723#ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
724 case Opt_check_integrity_including_extent_data:
725 btrfs_info(root->fs_info,
726 "enabling check integrity including extent data");
727 btrfs_set_opt(info->mount_opt,
728 CHECK_INTEGRITY_INCLUDING_EXTENT_DATA);
729 btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
730 break;
731 case Opt_check_integrity:
732 btrfs_info(root->fs_info, "enabling check integrity");
733 btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
734 break;
735 case Opt_check_integrity_print_mask:
736 ret = match_int(&args[0], &intarg);
737 if (ret) {
738 goto out;
739 } else if (intarg >= 0) {
740 info->check_integrity_print_mask = intarg;
741 btrfs_info(root->fs_info, "check_integrity_print_mask 0x%x",
742 info->check_integrity_print_mask);
743 } else {
744 ret = -EINVAL;
745 goto out;
746 }
747 break;
748#else
749 case Opt_check_integrity_including_extent_data:
750 case Opt_check_integrity:
751 case Opt_check_integrity_print_mask:
752 btrfs_err(root->fs_info,
753 "support for check_integrity* not compiled in!");
754 ret = -EINVAL;
755 goto out;
756#endif
757 case Opt_fatal_errors:
758 if (strcmp(args[0].from, "panic") == 0)
759 btrfs_set_opt(info->mount_opt,
760 PANIC_ON_FATAL_ERROR);
761 else if (strcmp(args[0].from, "bug") == 0)
762 btrfs_clear_opt(info->mount_opt,
763 PANIC_ON_FATAL_ERROR);
764 else {
765 ret = -EINVAL;
766 goto out;
767 }
768 break;
769 case Opt_commit_interval:
770 intarg = 0;
771 ret = match_int(&args[0], &intarg);
772 if (ret < 0) {
773 btrfs_err(root->fs_info, "invalid commit interval");
774 ret = -EINVAL;
775 goto out;
776 }
777 if (intarg > 0) {
778 if (intarg > 300) {
779 btrfs_warn(root->fs_info, "excessive commit interval %d",
780 intarg);
781 }
782 info->commit_interval = intarg;
783 } else {
784 btrfs_info(root->fs_info, "using default commit interval %ds",
785 BTRFS_DEFAULT_COMMIT_INTERVAL);
786 info->commit_interval = BTRFS_DEFAULT_COMMIT_INTERVAL;
787 }
788 break;
789#ifdef CONFIG_BTRFS_DEBUG
790 case Opt_fragment_all:
791 btrfs_info(root->fs_info, "fragmenting all space");
792 btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
793 btrfs_set_opt(info->mount_opt, FRAGMENT_METADATA);
794 break;
795 case Opt_fragment_metadata:
796 btrfs_info(root->fs_info, "fragmenting metadata");
797 btrfs_set_opt(info->mount_opt,
798 FRAGMENT_METADATA);
799 break;
800 case Opt_fragment_data:
801 btrfs_info(root->fs_info, "fragmenting data");
802 btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
803 break;
804#endif
805 case Opt_err:
806 btrfs_info(root->fs_info, "unrecognized mount option '%s'", p);
807 ret = -EINVAL;
808 goto out;
809 default:
810 break;
811 }
812 }
813check:
814 /*
815 * Extra check for current option against current flag
816 */
817 if (btrfs_test_opt(root, NOLOGREPLAY) && !(new_flags & MS_RDONLY)) {
818 btrfs_err(root->fs_info,
819 "nologreplay must be used with ro mount option");
820 ret = -EINVAL;
821 }
822out:
823 if (btrfs_fs_compat_ro(root->fs_info, FREE_SPACE_TREE) &&
824 !btrfs_test_opt(root, FREE_SPACE_TREE) &&
825 !btrfs_test_opt(root, CLEAR_CACHE)) {
826 btrfs_err(root->fs_info, "cannot disable free space tree");
827 ret = -EINVAL;
828
829 }
830 if (!ret && btrfs_test_opt(root, SPACE_CACHE))
831 btrfs_info(root->fs_info, "disk space caching is enabled");
832 if (!ret && btrfs_test_opt(root, FREE_SPACE_TREE))
833 btrfs_info(root->fs_info, "using free space tree");
834 kfree(orig);
835 return ret;
836}
837
838/*
839 * Parse mount options that are required early in the mount process.
840 *
841 * All other options will be parsed on much later in the mount process and
842 * only when we need to allocate a new super block.
843 */
844static int btrfs_parse_early_options(const char *options, fmode_t flags,
845 void *holder, char **subvol_name, u64 *subvol_objectid,
846 struct btrfs_fs_devices **fs_devices)
847{
848 substring_t args[MAX_OPT_ARGS];
849 char *device_name, *opts, *orig, *p;
850 char *num = NULL;
851 int error = 0;
852
853 if (!options)
854 return 0;
855
856 /*
857 * strsep changes the string, duplicate it because parse_options
858 * gets called twice
859 */
860 opts = kstrdup(options, GFP_KERNEL);
861 if (!opts)
862 return -ENOMEM;
863 orig = opts;
864
865 while ((p = strsep(&opts, ",")) != NULL) {
866 int token;
867 if (!*p)
868 continue;
869
870 token = match_token(p, tokens, args);
871 switch (token) {
872 case Opt_subvol:
873 kfree(*subvol_name);
874 *subvol_name = match_strdup(&args[0]);
875 if (!*subvol_name) {
876 error = -ENOMEM;
877 goto out;
878 }
879 break;
880 case Opt_subvolid:
881 num = match_strdup(&args[0]);
882 if (num) {
883 *subvol_objectid = memparse(num, NULL);
884 kfree(num);
885 /* we want the original fs_tree */
886 if (!*subvol_objectid)
887 *subvol_objectid =
888 BTRFS_FS_TREE_OBJECTID;
889 } else {
890 error = -EINVAL;
891 goto out;
892 }
893 break;
894 case Opt_subvolrootid:
895 printk(KERN_WARNING
896 "BTRFS: 'subvolrootid' mount option is deprecated and has "
897 "no effect\n");
898 break;
899 case Opt_device:
900 device_name = match_strdup(&args[0]);
901 if (!device_name) {
902 error = -ENOMEM;
903 goto out;
904 }
905 error = btrfs_scan_one_device(device_name,
906 flags, holder, fs_devices);
907 kfree(device_name);
908 if (error)
909 goto out;
910 break;
911 default:
912 break;
913 }
914 }
915
916out:
917 kfree(orig);
918 return error;
919}
920
921static char *get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
922 u64 subvol_objectid)
923{
924 struct btrfs_root *root = fs_info->tree_root;
925 struct btrfs_root *fs_root;
926 struct btrfs_root_ref *root_ref;
927 struct btrfs_inode_ref *inode_ref;
928 struct btrfs_key key;
929 struct btrfs_path *path = NULL;
930 char *name = NULL, *ptr;
931 u64 dirid;
932 int len;
933 int ret;
934
935 path = btrfs_alloc_path();
936 if (!path) {
937 ret = -ENOMEM;
938 goto err;
939 }
940 path->leave_spinning = 1;
941
942 name = kmalloc(PATH_MAX, GFP_NOFS);
943 if (!name) {
944 ret = -ENOMEM;
945 goto err;
946 }
947 ptr = name + PATH_MAX - 1;
948 ptr[0] = '\0';
949
950 /*
951 * Walk up the subvolume trees in the tree of tree roots by root
952 * backrefs until we hit the top-level subvolume.
953 */
954 while (subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
955 key.objectid = subvol_objectid;
956 key.type = BTRFS_ROOT_BACKREF_KEY;
957 key.offset = (u64)-1;
958
959 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
960 if (ret < 0) {
961 goto err;
962 } else if (ret > 0) {
963 ret = btrfs_previous_item(root, path, subvol_objectid,
964 BTRFS_ROOT_BACKREF_KEY);
965 if (ret < 0) {
966 goto err;
967 } else if (ret > 0) {
968 ret = -ENOENT;
969 goto err;
970 }
971 }
972
973 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
974 subvol_objectid = key.offset;
975
976 root_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
977 struct btrfs_root_ref);
978 len = btrfs_root_ref_name_len(path->nodes[0], root_ref);
979 ptr -= len + 1;
980 if (ptr < name) {
981 ret = -ENAMETOOLONG;
982 goto err;
983 }
984 read_extent_buffer(path->nodes[0], ptr + 1,
985 (unsigned long)(root_ref + 1), len);
986 ptr[0] = '/';
987 dirid = btrfs_root_ref_dirid(path->nodes[0], root_ref);
988 btrfs_release_path(path);
989
990 key.objectid = subvol_objectid;
991 key.type = BTRFS_ROOT_ITEM_KEY;
992 key.offset = (u64)-1;
993 fs_root = btrfs_read_fs_root_no_name(fs_info, &key);
994 if (IS_ERR(fs_root)) {
995 ret = PTR_ERR(fs_root);
996 goto err;
997 }
998
999 /*
1000 * Walk up the filesystem tree by inode refs until we hit the
1001 * root directory.
1002 */
1003 while (dirid != BTRFS_FIRST_FREE_OBJECTID) {
1004 key.objectid = dirid;
1005 key.type = BTRFS_INODE_REF_KEY;
1006 key.offset = (u64)-1;
1007
1008 ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0);
1009 if (ret < 0) {
1010 goto err;
1011 } else if (ret > 0) {
1012 ret = btrfs_previous_item(fs_root, path, dirid,
1013 BTRFS_INODE_REF_KEY);
1014 if (ret < 0) {
1015 goto err;
1016 } else if (ret > 0) {
1017 ret = -ENOENT;
1018 goto err;
1019 }
1020 }
1021
1022 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1023 dirid = key.offset;
1024
1025 inode_ref = btrfs_item_ptr(path->nodes[0],
1026 path->slots[0],
1027 struct btrfs_inode_ref);
1028 len = btrfs_inode_ref_name_len(path->nodes[0],
1029 inode_ref);
1030 ptr -= len + 1;
1031 if (ptr < name) {
1032 ret = -ENAMETOOLONG;
1033 goto err;
1034 }
1035 read_extent_buffer(path->nodes[0], ptr + 1,
1036 (unsigned long)(inode_ref + 1), len);
1037 ptr[0] = '/';
1038 btrfs_release_path(path);
1039 }
1040 }
1041
1042 btrfs_free_path(path);
1043 if (ptr == name + PATH_MAX - 1) {
1044 name[0] = '/';
1045 name[1] = '\0';
1046 } else {
1047 memmove(name, ptr, name + PATH_MAX - ptr);
1048 }
1049 return name;
1050
1051err:
1052 btrfs_free_path(path);
1053 kfree(name);
1054 return ERR_PTR(ret);
1055}
1056
1057static int get_default_subvol_objectid(struct btrfs_fs_info *fs_info, u64 *objectid)
1058{
1059 struct btrfs_root *root = fs_info->tree_root;
1060 struct btrfs_dir_item *di;
1061 struct btrfs_path *path;
1062 struct btrfs_key location;
1063 u64 dir_id;
1064
1065 path = btrfs_alloc_path();
1066 if (!path)
1067 return -ENOMEM;
1068 path->leave_spinning = 1;
1069
1070 /*
1071 * Find the "default" dir item which points to the root item that we
1072 * will mount by default if we haven't been given a specific subvolume
1073 * to mount.
1074 */
1075 dir_id = btrfs_super_root_dir(fs_info->super_copy);
1076 di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
1077 if (IS_ERR(di)) {
1078 btrfs_free_path(path);
1079 return PTR_ERR(di);
1080 }
1081 if (!di) {
1082 /*
1083 * Ok the default dir item isn't there. This is weird since
1084 * it's always been there, but don't freak out, just try and
1085 * mount the top-level subvolume.
1086 */
1087 btrfs_free_path(path);
1088 *objectid = BTRFS_FS_TREE_OBJECTID;
1089 return 0;
1090 }
1091
1092 btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
1093 btrfs_free_path(path);
1094 *objectid = location.objectid;
1095 return 0;
1096}
1097
1098static int btrfs_fill_super(struct super_block *sb,
1099 struct btrfs_fs_devices *fs_devices,
1100 void *data, int silent)
1101{
1102 struct inode *inode;
1103 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1104 struct btrfs_key key;
1105 int err;
1106
1107 sb->s_maxbytes = MAX_LFS_FILESIZE;
1108 sb->s_magic = BTRFS_SUPER_MAGIC;
1109 sb->s_op = &btrfs_super_ops;
1110 sb->s_d_op = &btrfs_dentry_operations;
1111 sb->s_export_op = &btrfs_export_ops;
1112 sb->s_xattr = btrfs_xattr_handlers;
1113 sb->s_time_gran = 1;
1114#ifdef CONFIG_BTRFS_FS_POSIX_ACL
1115 sb->s_flags |= MS_POSIXACL;
1116#endif
1117 sb->s_flags |= MS_I_VERSION;
1118 sb->s_iflags |= SB_I_CGROUPWB;
1119 err = open_ctree(sb, fs_devices, (char *)data);
1120 if (err) {
1121 printk(KERN_ERR "BTRFS: open_ctree failed\n");
1122 return err;
1123 }
1124
1125 key.objectid = BTRFS_FIRST_FREE_OBJECTID;
1126 key.type = BTRFS_INODE_ITEM_KEY;
1127 key.offset = 0;
1128 inode = btrfs_iget(sb, &key, fs_info->fs_root, NULL);
1129 if (IS_ERR(inode)) {
1130 err = PTR_ERR(inode);
1131 goto fail_close;
1132 }
1133
1134 sb->s_root = d_make_root(inode);
1135 if (!sb->s_root) {
1136 err = -ENOMEM;
1137 goto fail_close;
1138 }
1139
1140 save_mount_options(sb, data);
1141 cleancache_init_fs(sb);
1142 sb->s_flags |= MS_ACTIVE;
1143 return 0;
1144
1145fail_close:
1146 close_ctree(fs_info->tree_root);
1147 return err;
1148}
1149
1150int btrfs_sync_fs(struct super_block *sb, int wait)
1151{
1152 struct btrfs_trans_handle *trans;
1153 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1154 struct btrfs_root *root = fs_info->tree_root;
1155
1156 trace_btrfs_sync_fs(wait);
1157
1158 if (!wait) {
1159 filemap_flush(fs_info->btree_inode->i_mapping);
1160 return 0;
1161 }
1162
1163 btrfs_wait_ordered_roots(fs_info, -1);
1164
1165 trans = btrfs_attach_transaction_barrier(root);
1166 if (IS_ERR(trans)) {
1167 /* no transaction, don't bother */
1168 if (PTR_ERR(trans) == -ENOENT) {
1169 /*
1170 * Exit unless we have some pending changes
1171 * that need to go through commit
1172 */
1173 if (fs_info->pending_changes == 0)
1174 return 0;
1175 /*
1176 * A non-blocking test if the fs is frozen. We must not
1177 * start a new transaction here otherwise a deadlock
1178 * happens. The pending operations are delayed to the
1179 * next commit after thawing.
1180 */
1181 if (__sb_start_write(sb, SB_FREEZE_WRITE, false))
1182 __sb_end_write(sb, SB_FREEZE_WRITE);
1183 else
1184 return 0;
1185 trans = btrfs_start_transaction(root, 0);
1186 }
1187 if (IS_ERR(trans))
1188 return PTR_ERR(trans);
1189 }
1190 return btrfs_commit_transaction(trans, root);
1191}
1192
1193static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
1194{
1195 struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
1196 struct btrfs_root *root = info->tree_root;
1197 char *compress_type;
1198
1199 if (btrfs_test_opt(root, DEGRADED))
1200 seq_puts(seq, ",degraded");
1201 if (btrfs_test_opt(root, NODATASUM))
1202 seq_puts(seq, ",nodatasum");
1203 if (btrfs_test_opt(root, NODATACOW))
1204 seq_puts(seq, ",nodatacow");
1205 if (btrfs_test_opt(root, NOBARRIER))
1206 seq_puts(seq, ",nobarrier");
1207 if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE)
1208 seq_printf(seq, ",max_inline=%llu", info->max_inline);
1209 if (info->alloc_start != 0)
1210 seq_printf(seq, ",alloc_start=%llu", info->alloc_start);
1211 if (info->thread_pool_size != min_t(unsigned long,
1212 num_online_cpus() + 2, 8))
1213 seq_printf(seq, ",thread_pool=%d", info->thread_pool_size);
1214 if (btrfs_test_opt(root, COMPRESS)) {
1215 if (info->compress_type == BTRFS_COMPRESS_ZLIB)
1216 compress_type = "zlib";
1217 else
1218 compress_type = "lzo";
1219 if (btrfs_test_opt(root, FORCE_COMPRESS))
1220 seq_printf(seq, ",compress-force=%s", compress_type);
1221 else
1222 seq_printf(seq, ",compress=%s", compress_type);
1223 }
1224 if (btrfs_test_opt(root, NOSSD))
1225 seq_puts(seq, ",nossd");
1226 if (btrfs_test_opt(root, SSD_SPREAD))
1227 seq_puts(seq, ",ssd_spread");
1228 else if (btrfs_test_opt(root, SSD))
1229 seq_puts(seq, ",ssd");
1230 if (btrfs_test_opt(root, NOTREELOG))
1231 seq_puts(seq, ",notreelog");
1232 if (btrfs_test_opt(root, NOLOGREPLAY))
1233 seq_puts(seq, ",nologreplay");
1234 if (btrfs_test_opt(root, FLUSHONCOMMIT))
1235 seq_puts(seq, ",flushoncommit");
1236 if (btrfs_test_opt(root, DISCARD))
1237 seq_puts(seq, ",discard");
1238 if (!(root->fs_info->sb->s_flags & MS_POSIXACL))
1239 seq_puts(seq, ",noacl");
1240 if (btrfs_test_opt(root, SPACE_CACHE))
1241 seq_puts(seq, ",space_cache");
1242 else if (btrfs_test_opt(root, FREE_SPACE_TREE))
1243 seq_puts(seq, ",space_cache=v2");
1244 else
1245 seq_puts(seq, ",nospace_cache");
1246 if (btrfs_test_opt(root, RESCAN_UUID_TREE))
1247 seq_puts(seq, ",rescan_uuid_tree");
1248 if (btrfs_test_opt(root, CLEAR_CACHE))
1249 seq_puts(seq, ",clear_cache");
1250 if (btrfs_test_opt(root, USER_SUBVOL_RM_ALLOWED))
1251 seq_puts(seq, ",user_subvol_rm_allowed");
1252 if (btrfs_test_opt(root, ENOSPC_DEBUG))
1253 seq_puts(seq, ",enospc_debug");
1254 if (btrfs_test_opt(root, AUTO_DEFRAG))
1255 seq_puts(seq, ",autodefrag");
1256 if (btrfs_test_opt(root, INODE_MAP_CACHE))
1257 seq_puts(seq, ",inode_cache");
1258 if (btrfs_test_opt(root, SKIP_BALANCE))
1259 seq_puts(seq, ",skip_balance");
1260#ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
1261 if (btrfs_test_opt(root, CHECK_INTEGRITY_INCLUDING_EXTENT_DATA))
1262 seq_puts(seq, ",check_int_data");
1263 else if (btrfs_test_opt(root, CHECK_INTEGRITY))
1264 seq_puts(seq, ",check_int");
1265 if (info->check_integrity_print_mask)
1266 seq_printf(seq, ",check_int_print_mask=%d",
1267 info->check_integrity_print_mask);
1268#endif
1269 if (info->metadata_ratio)
1270 seq_printf(seq, ",metadata_ratio=%d",
1271 info->metadata_ratio);
1272 if (btrfs_test_opt(root, PANIC_ON_FATAL_ERROR))
1273 seq_puts(seq, ",fatal_errors=panic");
1274 if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL)
1275 seq_printf(seq, ",commit=%d", info->commit_interval);
1276#ifdef CONFIG_BTRFS_DEBUG
1277 if (btrfs_test_opt(root, FRAGMENT_DATA))
1278 seq_puts(seq, ",fragment=data");
1279 if (btrfs_test_opt(root, FRAGMENT_METADATA))
1280 seq_puts(seq, ",fragment=metadata");
1281#endif
1282 seq_printf(seq, ",subvolid=%llu",
1283 BTRFS_I(d_inode(dentry))->root->root_key.objectid);
1284 seq_puts(seq, ",subvol=");
1285 seq_dentry(seq, dentry, " \t\n\\");
1286 return 0;
1287}
1288
1289static int btrfs_test_super(struct super_block *s, void *data)
1290{
1291 struct btrfs_fs_info *p = data;
1292 struct btrfs_fs_info *fs_info = btrfs_sb(s);
1293
1294 return fs_info->fs_devices == p->fs_devices;
1295}
1296
1297static int btrfs_set_super(struct super_block *s, void *data)
1298{
1299 int err = set_anon_super(s, data);
1300 if (!err)
1301 s->s_fs_info = data;
1302 return err;
1303}
1304
1305/*
1306 * subvolumes are identified by ino 256
1307 */
1308static inline int is_subvolume_inode(struct inode *inode)
1309{
1310 if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
1311 return 1;
1312 return 0;
1313}
1314
1315/*
1316 * This will add subvolid=0 to the argument string while removing any subvol=
1317 * and subvolid= arguments to make sure we get the top-level root for path
1318 * walking to the subvol we want.
1319 */
1320static char *setup_root_args(char *args)
1321{
1322 char *buf, *dst, *sep;
1323
1324 if (!args)
1325 return kstrdup("subvolid=0", GFP_NOFS);
1326
1327 /* The worst case is that we add ",subvolid=0" to the end. */
1328 buf = dst = kmalloc(strlen(args) + strlen(",subvolid=0") + 1, GFP_NOFS);
1329 if (!buf)
1330 return NULL;
1331
1332 while (1) {
1333 sep = strchrnul(args, ',');
1334 if (!strstarts(args, "subvol=") &&
1335 !strstarts(args, "subvolid=")) {
1336 memcpy(dst, args, sep - args);
1337 dst += sep - args;
1338 *dst++ = ',';
1339 }
1340 if (*sep)
1341 args = sep + 1;
1342 else
1343 break;
1344 }
1345 strcpy(dst, "subvolid=0");
1346
1347 return buf;
1348}
1349
1350static struct dentry *mount_subvol(const char *subvol_name, u64 subvol_objectid,
1351 int flags, const char *device_name,
1352 char *data)
1353{
1354 struct dentry *root;
1355 struct vfsmount *mnt = NULL;
1356 char *newargs;
1357 int ret;
1358
1359 newargs = setup_root_args(data);
1360 if (!newargs) {
1361 root = ERR_PTR(-ENOMEM);
1362 goto out;
1363 }
1364
1365 mnt = vfs_kern_mount(&btrfs_fs_type, flags, device_name, newargs);
1366 if (PTR_ERR_OR_ZERO(mnt) == -EBUSY) {
1367 if (flags & MS_RDONLY) {
1368 mnt = vfs_kern_mount(&btrfs_fs_type, flags & ~MS_RDONLY,
1369 device_name, newargs);
1370 } else {
1371 mnt = vfs_kern_mount(&btrfs_fs_type, flags | MS_RDONLY,
1372 device_name, newargs);
1373 if (IS_ERR(mnt)) {
1374 root = ERR_CAST(mnt);
1375 mnt = NULL;
1376 goto out;
1377 }
1378
1379 down_write(&mnt->mnt_sb->s_umount);
1380 ret = btrfs_remount(mnt->mnt_sb, &flags, NULL);
1381 up_write(&mnt->mnt_sb->s_umount);
1382 if (ret < 0) {
1383 root = ERR_PTR(ret);
1384 goto out;
1385 }
1386 }
1387 }
1388 if (IS_ERR(mnt)) {
1389 root = ERR_CAST(mnt);
1390 mnt = NULL;
1391 goto out;
1392 }
1393
1394 if (!subvol_name) {
1395 if (!subvol_objectid) {
1396 ret = get_default_subvol_objectid(btrfs_sb(mnt->mnt_sb),
1397 &subvol_objectid);
1398 if (ret) {
1399 root = ERR_PTR(ret);
1400 goto out;
1401 }
1402 }
1403 subvol_name = get_subvol_name_from_objectid(btrfs_sb(mnt->mnt_sb),
1404 subvol_objectid);
1405 if (IS_ERR(subvol_name)) {
1406 root = ERR_CAST(subvol_name);
1407 subvol_name = NULL;
1408 goto out;
1409 }
1410
1411 }
1412
1413 root = mount_subtree(mnt, subvol_name);
1414 /* mount_subtree() drops our reference on the vfsmount. */
1415 mnt = NULL;
1416
1417 if (!IS_ERR(root)) {
1418 struct super_block *s = root->d_sb;
1419 struct inode *root_inode = d_inode(root);
1420 u64 root_objectid = BTRFS_I(root_inode)->root->root_key.objectid;
1421
1422 ret = 0;
1423 if (!is_subvolume_inode(root_inode)) {
1424 pr_err("BTRFS: '%s' is not a valid subvolume\n",
1425 subvol_name);
1426 ret = -EINVAL;
1427 }
1428 if (subvol_objectid && root_objectid != subvol_objectid) {
1429 /*
1430 * This will also catch a race condition where a
1431 * subvolume which was passed by ID is renamed and
1432 * another subvolume is renamed over the old location.
1433 */
1434 pr_err("BTRFS: subvol '%s' does not match subvolid %llu\n",
1435 subvol_name, subvol_objectid);
1436 ret = -EINVAL;
1437 }
1438 if (ret) {
1439 dput(root);
1440 root = ERR_PTR(ret);
1441 deactivate_locked_super(s);
1442 }
1443 }
1444
1445out:
1446 mntput(mnt);
1447 kfree(newargs);
1448 kfree(subvol_name);
1449 return root;
1450}
1451
1452static int parse_security_options(char *orig_opts,
1453 struct security_mnt_opts *sec_opts)
1454{
1455 char *secdata = NULL;
1456 int ret = 0;
1457
1458 secdata = alloc_secdata();
1459 if (!secdata)
1460 return -ENOMEM;
1461 ret = security_sb_copy_data(orig_opts, secdata);
1462 if (ret) {
1463 free_secdata(secdata);
1464 return ret;
1465 }
1466 ret = security_sb_parse_opts_str(secdata, sec_opts);
1467 free_secdata(secdata);
1468 return ret;
1469}
1470
1471static int setup_security_options(struct btrfs_fs_info *fs_info,
1472 struct super_block *sb,
1473 struct security_mnt_opts *sec_opts)
1474{
1475 int ret = 0;
1476
1477 /*
1478 * Call security_sb_set_mnt_opts() to check whether new sec_opts
1479 * is valid.
1480 */
1481 ret = security_sb_set_mnt_opts(sb, sec_opts, 0, NULL);
1482 if (ret)
1483 return ret;
1484
1485#ifdef CONFIG_SECURITY
1486 if (!fs_info->security_opts.num_mnt_opts) {
1487 /* first time security setup, copy sec_opts to fs_info */
1488 memcpy(&fs_info->security_opts, sec_opts, sizeof(*sec_opts));
1489 } else {
1490 /*
1491 * Since SELinux(the only one supports security_mnt_opts) does
1492 * NOT support changing context during remount/mount same sb,
1493 * This must be the same or part of the same security options,
1494 * just free it.
1495 */
1496 security_free_mnt_opts(sec_opts);
1497 }
1498#endif
1499 return ret;
1500}
1501
1502/*
1503 * Find a superblock for the given device / mount point.
1504 *
1505 * Note: This is based on get_sb_bdev from fs/super.c with a few additions
1506 * for multiple device setup. Make sure to keep it in sync.
1507 */
1508static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
1509 const char *device_name, void *data)
1510{
1511 struct block_device *bdev = NULL;
1512 struct super_block *s;
1513 struct btrfs_fs_devices *fs_devices = NULL;
1514 struct btrfs_fs_info *fs_info = NULL;
1515 struct security_mnt_opts new_sec_opts;
1516 fmode_t mode = FMODE_READ;
1517 char *subvol_name = NULL;
1518 u64 subvol_objectid = 0;
1519 int error = 0;
1520
1521 if (!(flags & MS_RDONLY))
1522 mode |= FMODE_WRITE;
1523
1524 error = btrfs_parse_early_options(data, mode, fs_type,
1525 &subvol_name, &subvol_objectid,
1526 &fs_devices);
1527 if (error) {
1528 kfree(subvol_name);
1529 return ERR_PTR(error);
1530 }
1531
1532 if (subvol_name || subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
1533 /* mount_subvol() will free subvol_name. */
1534 return mount_subvol(subvol_name, subvol_objectid, flags,
1535 device_name, data);
1536 }
1537
1538 security_init_mnt_opts(&new_sec_opts);
1539 if (data) {
1540 error = parse_security_options(data, &new_sec_opts);
1541 if (error)
1542 return ERR_PTR(error);
1543 }
1544
1545 error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices);
1546 if (error)
1547 goto error_sec_opts;
1548
1549 /*
1550 * Setup a dummy root and fs_info for test/set super. This is because
1551 * we don't actually fill this stuff out until open_ctree, but we need
1552 * it for searching for existing supers, so this lets us do that and
1553 * then open_ctree will properly initialize everything later.
1554 */
1555 fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_NOFS);
1556 if (!fs_info) {
1557 error = -ENOMEM;
1558 goto error_sec_opts;
1559 }
1560
1561 fs_info->fs_devices = fs_devices;
1562
1563 fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
1564 fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
1565 security_init_mnt_opts(&fs_info->security_opts);
1566 if (!fs_info->super_copy || !fs_info->super_for_commit) {
1567 error = -ENOMEM;
1568 goto error_fs_info;
1569 }
1570
1571 error = btrfs_open_devices(fs_devices, mode, fs_type);
1572 if (error)
1573 goto error_fs_info;
1574
1575 if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
1576 error = -EACCES;
1577 goto error_close_devices;
1578 }
1579
1580 bdev = fs_devices->latest_bdev;
1581 s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | MS_NOSEC,
1582 fs_info);
1583 if (IS_ERR(s)) {
1584 error = PTR_ERR(s);
1585 goto error_close_devices;
1586 }
1587
1588 if (s->s_root) {
1589 btrfs_close_devices(fs_devices);
1590 free_fs_info(fs_info);
1591 if ((flags ^ s->s_flags) & MS_RDONLY)
1592 error = -EBUSY;
1593 } else {
1594 snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev);
1595 btrfs_sb(s)->bdev_holder = fs_type;
1596 error = btrfs_fill_super(s, fs_devices, data,
1597 flags & MS_SILENT ? 1 : 0);
1598 }
1599 if (error) {
1600 deactivate_locked_super(s);
1601 goto error_sec_opts;
1602 }
1603
1604 fs_info = btrfs_sb(s);
1605 error = setup_security_options(fs_info, s, &new_sec_opts);
1606 if (error) {
1607 deactivate_locked_super(s);
1608 goto error_sec_opts;
1609 }
1610
1611 return dget(s->s_root);
1612
1613error_close_devices:
1614 btrfs_close_devices(fs_devices);
1615error_fs_info:
1616 free_fs_info(fs_info);
1617error_sec_opts:
1618 security_free_mnt_opts(&new_sec_opts);
1619 return ERR_PTR(error);
1620}
1621
1622static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
1623 int new_pool_size, int old_pool_size)
1624{
1625 if (new_pool_size == old_pool_size)
1626 return;
1627
1628 fs_info->thread_pool_size = new_pool_size;
1629
1630 btrfs_info(fs_info, "resize thread pool %d -> %d",
1631 old_pool_size, new_pool_size);
1632
1633 btrfs_workqueue_set_max(fs_info->workers, new_pool_size);
1634 btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size);
1635 btrfs_workqueue_set_max(fs_info->submit_workers, new_pool_size);
1636 btrfs_workqueue_set_max(fs_info->caching_workers, new_pool_size);
1637 btrfs_workqueue_set_max(fs_info->endio_workers, new_pool_size);
1638 btrfs_workqueue_set_max(fs_info->endio_meta_workers, new_pool_size);
1639 btrfs_workqueue_set_max(fs_info->endio_meta_write_workers,
1640 new_pool_size);
1641 btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size);
1642 btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
1643 btrfs_workqueue_set_max(fs_info->delayed_workers, new_pool_size);
1644 btrfs_workqueue_set_max(fs_info->readahead_workers, new_pool_size);
1645 btrfs_workqueue_set_max(fs_info->scrub_wr_completion_workers,
1646 new_pool_size);
1647}
1648
1649static inline void btrfs_remount_prepare(struct btrfs_fs_info *fs_info)
1650{
1651 set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1652}
1653
1654static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info,
1655 unsigned long old_opts, int flags)
1656{
1657 if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1658 (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1659 (flags & MS_RDONLY))) {
1660 /* wait for any defraggers to finish */
1661 wait_event(fs_info->transaction_wait,
1662 (atomic_read(&fs_info->defrag_running) == 0));
1663 if (flags & MS_RDONLY)
1664 sync_filesystem(fs_info->sb);
1665 }
1666}
1667
1668static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
1669 unsigned long old_opts)
1670{
1671 /*
1672 * We need cleanup all defragable inodes if the autodefragment is
1673 * close or the fs is R/O.
1674 */
1675 if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1676 (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1677 (fs_info->sb->s_flags & MS_RDONLY))) {
1678 btrfs_cleanup_defrag_inodes(fs_info);
1679 }
1680
1681 clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1682}
1683
1684static int btrfs_remount(struct super_block *sb, int *flags, char *data)
1685{
1686 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1687 struct btrfs_root *root = fs_info->tree_root;
1688 unsigned old_flags = sb->s_flags;
1689 unsigned long old_opts = fs_info->mount_opt;
1690 unsigned long old_compress_type = fs_info->compress_type;
1691 u64 old_max_inline = fs_info->max_inline;
1692 u64 old_alloc_start = fs_info->alloc_start;
1693 int old_thread_pool_size = fs_info->thread_pool_size;
1694 unsigned int old_metadata_ratio = fs_info->metadata_ratio;
1695 int ret;
1696
1697 sync_filesystem(sb);
1698 btrfs_remount_prepare(fs_info);
1699
1700 if (data) {
1701 struct security_mnt_opts new_sec_opts;
1702
1703 security_init_mnt_opts(&new_sec_opts);
1704 ret = parse_security_options(data, &new_sec_opts);
1705 if (ret)
1706 goto restore;
1707 ret = setup_security_options(fs_info, sb,
1708 &new_sec_opts);
1709 if (ret) {
1710 security_free_mnt_opts(&new_sec_opts);
1711 goto restore;
1712 }
1713 }
1714
1715 ret = btrfs_parse_options(root, data, *flags);
1716 if (ret) {
1717 ret = -EINVAL;
1718 goto restore;
1719 }
1720
1721 btrfs_remount_begin(fs_info, old_opts, *flags);
1722 btrfs_resize_thread_pool(fs_info,
1723 fs_info->thread_pool_size, old_thread_pool_size);
1724
1725 if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1726 goto out;
1727
1728 if (*flags & MS_RDONLY) {
1729 /*
1730 * this also happens on 'umount -rf' or on shutdown, when
1731 * the filesystem is busy.
1732 */
1733 cancel_work_sync(&fs_info->async_reclaim_work);
1734
1735 /* wait for the uuid_scan task to finish */
1736 down(&fs_info->uuid_tree_rescan_sem);
1737 /* avoid complains from lockdep et al. */
1738 up(&fs_info->uuid_tree_rescan_sem);
1739
1740 sb->s_flags |= MS_RDONLY;
1741
1742 /*
1743 * Setting MS_RDONLY will put the cleaner thread to
1744 * sleep at the next loop if it's already active.
1745 * If it's already asleep, we'll leave unused block
1746 * groups on disk until we're mounted read-write again
1747 * unless we clean them up here.
1748 */
1749 btrfs_delete_unused_bgs(fs_info);
1750
1751 btrfs_dev_replace_suspend_for_unmount(fs_info);
1752 btrfs_scrub_cancel(fs_info);
1753 btrfs_pause_balance(fs_info);
1754
1755 ret = btrfs_commit_super(root);
1756 if (ret)
1757 goto restore;
1758 } else {
1759 if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state)) {
1760 btrfs_err(fs_info,
1761 "Remounting read-write after error is not allowed");
1762 ret = -EINVAL;
1763 goto restore;
1764 }
1765 if (fs_info->fs_devices->rw_devices == 0) {
1766 ret = -EACCES;
1767 goto restore;
1768 }
1769
1770 if (fs_info->fs_devices->missing_devices >
1771 fs_info->num_tolerated_disk_barrier_failures &&
1772 !(*flags & MS_RDONLY)) {
1773 btrfs_warn(fs_info,
1774 "too many missing devices, writeable remount is not allowed");
1775 ret = -EACCES;
1776 goto restore;
1777 }
1778
1779 if (btrfs_super_log_root(fs_info->super_copy) != 0) {
1780 ret = -EINVAL;
1781 goto restore;
1782 }
1783
1784 ret = btrfs_cleanup_fs_roots(fs_info);
1785 if (ret)
1786 goto restore;
1787
1788 /* recover relocation */
1789 mutex_lock(&fs_info->cleaner_mutex);
1790 ret = btrfs_recover_relocation(root);
1791 mutex_unlock(&fs_info->cleaner_mutex);
1792 if (ret)
1793 goto restore;
1794
1795 ret = btrfs_resume_balance_async(fs_info);
1796 if (ret)
1797 goto restore;
1798
1799 ret = btrfs_resume_dev_replace_async(fs_info);
1800 if (ret) {
1801 btrfs_warn(fs_info, "failed to resume dev_replace");
1802 goto restore;
1803 }
1804
1805 if (!fs_info->uuid_root) {
1806 btrfs_info(fs_info, "creating UUID tree");
1807 ret = btrfs_create_uuid_tree(fs_info);
1808 if (ret) {
1809 btrfs_warn(fs_info, "failed to create the UUID tree %d", ret);
1810 goto restore;
1811 }
1812 }
1813 sb->s_flags &= ~MS_RDONLY;
1814 }
1815out:
1816 wake_up_process(fs_info->transaction_kthread);
1817 btrfs_remount_cleanup(fs_info, old_opts);
1818 return 0;
1819
1820restore:
1821 /* We've hit an error - don't reset MS_RDONLY */
1822 if (sb->s_flags & MS_RDONLY)
1823 old_flags |= MS_RDONLY;
1824 sb->s_flags = old_flags;
1825 fs_info->mount_opt = old_opts;
1826 fs_info->compress_type = old_compress_type;
1827 fs_info->max_inline = old_max_inline;
1828 mutex_lock(&fs_info->chunk_mutex);
1829 fs_info->alloc_start = old_alloc_start;
1830 mutex_unlock(&fs_info->chunk_mutex);
1831 btrfs_resize_thread_pool(fs_info,
1832 old_thread_pool_size, fs_info->thread_pool_size);
1833 fs_info->metadata_ratio = old_metadata_ratio;
1834 btrfs_remount_cleanup(fs_info, old_opts);
1835 return ret;
1836}
1837
1838/* Used to sort the devices by max_avail(descending sort) */
1839static int btrfs_cmp_device_free_bytes(const void *dev_info1,
1840 const void *dev_info2)
1841{
1842 if (((struct btrfs_device_info *)dev_info1)->max_avail >
1843 ((struct btrfs_device_info *)dev_info2)->max_avail)
1844 return -1;
1845 else if (((struct btrfs_device_info *)dev_info1)->max_avail <
1846 ((struct btrfs_device_info *)dev_info2)->max_avail)
1847 return 1;
1848 else
1849 return 0;
1850}
1851
1852/*
1853 * sort the devices by max_avail, in which max free extent size of each device
1854 * is stored.(Descending Sort)
1855 */
1856static inline void btrfs_descending_sort_devices(
1857 struct btrfs_device_info *devices,
1858 size_t nr_devices)
1859{
1860 sort(devices, nr_devices, sizeof(struct btrfs_device_info),
1861 btrfs_cmp_device_free_bytes, NULL);
1862}
1863
1864/*
1865 * The helper to calc the free space on the devices that can be used to store
1866 * file data.
1867 */
1868static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes)
1869{
1870 struct btrfs_fs_info *fs_info = root->fs_info;
1871 struct btrfs_device_info *devices_info;
1872 struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
1873 struct btrfs_device *device;
1874 u64 skip_space;
1875 u64 type;
1876 u64 avail_space;
1877 u64 used_space;
1878 u64 min_stripe_size;
1879 int min_stripes = 1, num_stripes = 1;
1880 int i = 0, nr_devices;
1881 int ret;
1882
1883 /*
1884 * We aren't under the device list lock, so this is racey-ish, but good
1885 * enough for our purposes.
1886 */
1887 nr_devices = fs_info->fs_devices->open_devices;
1888 if (!nr_devices) {
1889 smp_mb();
1890 nr_devices = fs_info->fs_devices->open_devices;
1891 ASSERT(nr_devices);
1892 if (!nr_devices) {
1893 *free_bytes = 0;
1894 return 0;
1895 }
1896 }
1897
1898 devices_info = kmalloc_array(nr_devices, sizeof(*devices_info),
1899 GFP_NOFS);
1900 if (!devices_info)
1901 return -ENOMEM;
1902
1903 /* calc min stripe number for data space alloction */
1904 type = btrfs_get_alloc_profile(root, 1);
1905 if (type & BTRFS_BLOCK_GROUP_RAID0) {
1906 min_stripes = 2;
1907 num_stripes = nr_devices;
1908 } else if (type & BTRFS_BLOCK_GROUP_RAID1) {
1909 min_stripes = 2;
1910 num_stripes = 2;
1911 } else if (type & BTRFS_BLOCK_GROUP_RAID10) {
1912 min_stripes = 4;
1913 num_stripes = 4;
1914 }
1915
1916 if (type & BTRFS_BLOCK_GROUP_DUP)
1917 min_stripe_size = 2 * BTRFS_STRIPE_LEN;
1918 else
1919 min_stripe_size = BTRFS_STRIPE_LEN;
1920
1921 if (fs_info->alloc_start)
1922 mutex_lock(&fs_devices->device_list_mutex);
1923 rcu_read_lock();
1924 list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
1925 if (!device->in_fs_metadata || !device->bdev ||
1926 device->is_tgtdev_for_dev_replace)
1927 continue;
1928
1929 if (i >= nr_devices)
1930 break;
1931
1932 avail_space = device->total_bytes - device->bytes_used;
1933
1934 /* align with stripe_len */
1935 avail_space = div_u64(avail_space, BTRFS_STRIPE_LEN);
1936 avail_space *= BTRFS_STRIPE_LEN;
1937
1938 /*
1939 * In order to avoid overwritting the superblock on the drive,
1940 * btrfs starts at an offset of at least 1MB when doing chunk
1941 * allocation.
1942 */
1943 skip_space = SZ_1M;
1944
1945 /* user can set the offset in fs_info->alloc_start. */
1946 if (fs_info->alloc_start &&
1947 fs_info->alloc_start + BTRFS_STRIPE_LEN <=
1948 device->total_bytes) {
1949 rcu_read_unlock();
1950 skip_space = max(fs_info->alloc_start, skip_space);
1951
1952 /*
1953 * btrfs can not use the free space in
1954 * [0, skip_space - 1], we must subtract it from the
1955 * total. In order to implement it, we account the used
1956 * space in this range first.
1957 */
1958 ret = btrfs_account_dev_extents_size(device, 0,
1959 skip_space - 1,
1960 &used_space);
1961 if (ret) {
1962 kfree(devices_info);
1963 mutex_unlock(&fs_devices->device_list_mutex);
1964 return ret;
1965 }
1966
1967 rcu_read_lock();
1968
1969 /* calc the free space in [0, skip_space - 1] */
1970 skip_space -= used_space;
1971 }
1972
1973 /*
1974 * we can use the free space in [0, skip_space - 1], subtract
1975 * it from the total.
1976 */
1977 if (avail_space && avail_space >= skip_space)
1978 avail_space -= skip_space;
1979 else
1980 avail_space = 0;
1981
1982 if (avail_space < min_stripe_size)
1983 continue;
1984
1985 devices_info[i].dev = device;
1986 devices_info[i].max_avail = avail_space;
1987
1988 i++;
1989 }
1990 rcu_read_unlock();
1991 if (fs_info->alloc_start)
1992 mutex_unlock(&fs_devices->device_list_mutex);
1993
1994 nr_devices = i;
1995
1996 btrfs_descending_sort_devices(devices_info, nr_devices);
1997
1998 i = nr_devices - 1;
1999 avail_space = 0;
2000 while (nr_devices >= min_stripes) {
2001 if (num_stripes > nr_devices)
2002 num_stripes = nr_devices;
2003
2004 if (devices_info[i].max_avail >= min_stripe_size) {
2005 int j;
2006 u64 alloc_size;
2007
2008 avail_space += devices_info[i].max_avail * num_stripes;
2009 alloc_size = devices_info[i].max_avail;
2010 for (j = i + 1 - num_stripes; j <= i; j++)
2011 devices_info[j].max_avail -= alloc_size;
2012 }
2013 i--;
2014 nr_devices--;
2015 }
2016
2017 kfree(devices_info);
2018 *free_bytes = avail_space;
2019 return 0;
2020}
2021
2022/*
2023 * Calculate numbers for 'df', pessimistic in case of mixed raid profiles.
2024 *
2025 * If there's a redundant raid level at DATA block groups, use the respective
2026 * multiplier to scale the sizes.
2027 *
2028 * Unused device space usage is based on simulating the chunk allocator
2029 * algorithm that respects the device sizes, order of allocations and the
2030 * 'alloc_start' value, this is a close approximation of the actual use but
2031 * there are other factors that may change the result (like a new metadata
2032 * chunk).
2033 *
2034 * If metadata is exhausted, f_bavail will be 0.
2035 *
2036 * FIXME: not accurate for mixed block groups, total and free/used are ok,
2037 * available appears slightly larger.
2038 */
2039static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
2040{
2041 struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
2042 struct btrfs_super_block *disk_super = fs_info->super_copy;
2043 struct list_head *head = &fs_info->space_info;
2044 struct btrfs_space_info *found;
2045 u64 total_used = 0;
2046 u64 total_free_data = 0;
2047 u64 total_free_meta = 0;
2048 int bits = dentry->d_sb->s_blocksize_bits;
2049 __be32 *fsid = (__be32 *)fs_info->fsid;
2050 unsigned factor = 1;
2051 struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
2052 int ret;
2053 u64 thresh = 0;
2054
2055 /*
2056 * holding chunk_muext to avoid allocating new chunks, holding
2057 * device_list_mutex to avoid the device being removed
2058 */
2059 rcu_read_lock();
2060 list_for_each_entry_rcu(found, head, list) {
2061 if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
2062 int i;
2063
2064 total_free_data += found->disk_total - found->disk_used;
2065 total_free_data -=
2066 btrfs_account_ro_block_groups_free_space(found);
2067
2068 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
2069 if (!list_empty(&found->block_groups[i])) {
2070 switch (i) {
2071 case BTRFS_RAID_DUP:
2072 case BTRFS_RAID_RAID1:
2073 case BTRFS_RAID_RAID10:
2074 factor = 2;
2075 }
2076 }
2077 }
2078 }
2079 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
2080 total_free_meta += found->disk_total - found->disk_used;
2081
2082 total_used += found->disk_used;
2083 }
2084
2085 rcu_read_unlock();
2086
2087 buf->f_blocks = div_u64(btrfs_super_total_bytes(disk_super), factor);
2088 buf->f_blocks >>= bits;
2089 buf->f_bfree = buf->f_blocks - (div_u64(total_used, factor) >> bits);
2090
2091 /* Account global block reserve as used, it's in logical size already */
2092 spin_lock(&block_rsv->lock);
2093 buf->f_bfree -= block_rsv->size >> bits;
2094 spin_unlock(&block_rsv->lock);
2095
2096 buf->f_bavail = div_u64(total_free_data, factor);
2097 ret = btrfs_calc_avail_data_space(fs_info->tree_root, &total_free_data);
2098 if (ret)
2099 return ret;
2100 buf->f_bavail += div_u64(total_free_data, factor);
2101 buf->f_bavail = buf->f_bavail >> bits;
2102
2103 /*
2104 * We calculate the remaining metadata space minus global reserve. If
2105 * this is (supposedly) smaller than zero, there's no space. But this
2106 * does not hold in practice, the exhausted state happens where's still
2107 * some positive delta. So we apply some guesswork and compare the
2108 * delta to a 4M threshold. (Practically observed delta was ~2M.)
2109 *
2110 * We probably cannot calculate the exact threshold value because this
2111 * depends on the internal reservations requested by various
2112 * operations, so some operations that consume a few metadata will
2113 * succeed even if the Avail is zero. But this is better than the other
2114 * way around.
2115 */
2116 thresh = 4 * 1024 * 1024;
2117
2118 if (total_free_meta - thresh < block_rsv->size)
2119 buf->f_bavail = 0;
2120
2121 buf->f_type = BTRFS_SUPER_MAGIC;
2122 buf->f_bsize = dentry->d_sb->s_blocksize;
2123 buf->f_namelen = BTRFS_NAME_LEN;
2124
2125 /* We treat it as constant endianness (it doesn't matter _which_)
2126 because we want the fsid to come out the same whether mounted
2127 on a big-endian or little-endian host */
2128 buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
2129 buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
2130 /* Mask in the root object ID too, to disambiguate subvols */
2131 buf->f_fsid.val[0] ^= BTRFS_I(d_inode(dentry))->root->objectid >> 32;
2132 buf->f_fsid.val[1] ^= BTRFS_I(d_inode(dentry))->root->objectid;
2133
2134 return 0;
2135}
2136
2137static void btrfs_kill_super(struct super_block *sb)
2138{
2139 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2140 kill_anon_super(sb);
2141 free_fs_info(fs_info);
2142}
2143
2144static struct file_system_type btrfs_fs_type = {
2145 .owner = THIS_MODULE,
2146 .name = "btrfs",
2147 .mount = btrfs_mount,
2148 .kill_sb = btrfs_kill_super,
2149 .fs_flags = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,
2150};
2151MODULE_ALIAS_FS("btrfs");
2152
2153static int btrfs_control_open(struct inode *inode, struct file *file)
2154{
2155 /*
2156 * The control file's private_data is used to hold the
2157 * transaction when it is started and is used to keep
2158 * track of whether a transaction is already in progress.
2159 */
2160 file->private_data = NULL;
2161 return 0;
2162}
2163
2164/*
2165 * used by btrfsctl to scan devices when no FS is mounted
2166 */
2167static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
2168 unsigned long arg)
2169{
2170 struct btrfs_ioctl_vol_args *vol;
2171 struct btrfs_fs_devices *fs_devices;
2172 int ret = -ENOTTY;
2173
2174 if (!capable(CAP_SYS_ADMIN))
2175 return -EPERM;
2176
2177 vol = memdup_user((void __user *)arg, sizeof(*vol));
2178 if (IS_ERR(vol))
2179 return PTR_ERR(vol);
2180
2181 switch (cmd) {
2182 case BTRFS_IOC_SCAN_DEV:
2183 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
2184 &btrfs_fs_type, &fs_devices);
2185 break;
2186 case BTRFS_IOC_DEVICES_READY:
2187 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
2188 &btrfs_fs_type, &fs_devices);
2189 if (ret)
2190 break;
2191 ret = !(fs_devices->num_devices == fs_devices->total_devices);
2192 break;
2193 case BTRFS_IOC_GET_SUPPORTED_FEATURES:
2194 ret = btrfs_ioctl_get_supported_features((void __user*)arg);
2195 break;
2196 }
2197
2198 kfree(vol);
2199 return ret;
2200}
2201
2202static int btrfs_freeze(struct super_block *sb)
2203{
2204 struct btrfs_trans_handle *trans;
2205 struct btrfs_root *root = btrfs_sb(sb)->tree_root;
2206
2207 trans = btrfs_attach_transaction_barrier(root);
2208 if (IS_ERR(trans)) {
2209 /* no transaction, don't bother */
2210 if (PTR_ERR(trans) == -ENOENT)
2211 return 0;
2212 return PTR_ERR(trans);
2213 }
2214 return btrfs_commit_transaction(trans, root);
2215}
2216
2217static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
2218{
2219 struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
2220 struct btrfs_fs_devices *cur_devices;
2221 struct btrfs_device *dev, *first_dev = NULL;
2222 struct list_head *head;
2223 struct rcu_string *name;
2224
2225 mutex_lock(&fs_info->fs_devices->device_list_mutex);
2226 cur_devices = fs_info->fs_devices;
2227 while (cur_devices) {
2228 head = &cur_devices->devices;
2229 list_for_each_entry(dev, head, dev_list) {
2230 if (dev->missing)
2231 continue;
2232 if (!dev->name)
2233 continue;
2234 if (!first_dev || dev->devid < first_dev->devid)
2235 first_dev = dev;
2236 }
2237 cur_devices = cur_devices->seed;
2238 }
2239
2240 if (first_dev) {
2241 rcu_read_lock();
2242 name = rcu_dereference(first_dev->name);
2243 seq_escape(m, name->str, " \t\n\\");
2244 rcu_read_unlock();
2245 } else {
2246 WARN_ON(1);
2247 }
2248 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2249 return 0;
2250}
2251
2252static const struct super_operations btrfs_super_ops = {
2253 .drop_inode = btrfs_drop_inode,
2254 .evict_inode = btrfs_evict_inode,
2255 .put_super = btrfs_put_super,
2256 .sync_fs = btrfs_sync_fs,
2257 .show_options = btrfs_show_options,
2258 .show_devname = btrfs_show_devname,
2259 .write_inode = btrfs_write_inode,
2260 .alloc_inode = btrfs_alloc_inode,
2261 .destroy_inode = btrfs_destroy_inode,
2262 .statfs = btrfs_statfs,
2263 .remount_fs = btrfs_remount,
2264 .freeze_fs = btrfs_freeze,
2265};
2266
2267static const struct file_operations btrfs_ctl_fops = {
2268 .open = btrfs_control_open,
2269 .unlocked_ioctl = btrfs_control_ioctl,
2270 .compat_ioctl = btrfs_control_ioctl,
2271 .owner = THIS_MODULE,
2272 .llseek = noop_llseek,
2273};
2274
2275static struct miscdevice btrfs_misc = {
2276 .minor = BTRFS_MINOR,
2277 .name = "btrfs-control",
2278 .fops = &btrfs_ctl_fops
2279};
2280
2281MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
2282MODULE_ALIAS("devname:btrfs-control");
2283
2284static int btrfs_interface_init(void)
2285{
2286 return misc_register(&btrfs_misc);
2287}
2288
2289static void btrfs_interface_exit(void)
2290{
2291 misc_deregister(&btrfs_misc);
2292}
2293
2294static void btrfs_print_mod_info(void)
2295{
2296 printk(KERN_INFO "Btrfs loaded"
2297#ifdef CONFIG_BTRFS_DEBUG
2298 ", debug=on"
2299#endif
2300#ifdef CONFIG_BTRFS_ASSERT
2301 ", assert=on"
2302#endif
2303#ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
2304 ", integrity-checker=on"
2305#endif
2306 "\n");
2307}
2308
2309static int btrfs_run_sanity_tests(void)
2310{
2311 int ret;
2312
2313 ret = btrfs_init_test_fs();
2314 if (ret)
2315 return ret;
2316
2317 ret = btrfs_test_free_space_cache();
2318 if (ret)
2319 goto out;
2320 ret = btrfs_test_extent_buffer_operations();
2321 if (ret)
2322 goto out;
2323 ret = btrfs_test_extent_io();
2324 if (ret)
2325 goto out;
2326 ret = btrfs_test_inodes();
2327 if (ret)
2328 goto out;
2329 ret = btrfs_test_qgroups();
2330 if (ret)
2331 goto out;
2332 ret = btrfs_test_free_space_tree();
2333out:
2334 btrfs_destroy_test_fs();
2335 return ret;
2336}
2337
2338static int __init init_btrfs_fs(void)
2339{
2340 int err;
2341
2342 err = btrfs_hash_init();
2343 if (err)
2344 return err;
2345
2346 btrfs_props_init();
2347
2348 err = btrfs_init_sysfs();
2349 if (err)
2350 goto free_hash;
2351
2352 btrfs_init_compress();
2353
2354 err = btrfs_init_cachep();
2355 if (err)
2356 goto free_compress;
2357
2358 err = extent_io_init();
2359 if (err)
2360 goto free_cachep;
2361
2362 err = extent_map_init();
2363 if (err)
2364 goto free_extent_io;
2365
2366 err = ordered_data_init();
2367 if (err)
2368 goto free_extent_map;
2369
2370 err = btrfs_delayed_inode_init();
2371 if (err)
2372 goto free_ordered_data;
2373
2374 err = btrfs_auto_defrag_init();
2375 if (err)
2376 goto free_delayed_inode;
2377
2378 err = btrfs_delayed_ref_init();
2379 if (err)
2380 goto free_auto_defrag;
2381
2382 err = btrfs_prelim_ref_init();
2383 if (err)
2384 goto free_delayed_ref;
2385
2386 err = btrfs_end_io_wq_init();
2387 if (err)
2388 goto free_prelim_ref;
2389
2390 err = btrfs_interface_init();
2391 if (err)
2392 goto free_end_io_wq;
2393
2394 btrfs_init_lockdep();
2395
2396 btrfs_print_mod_info();
2397
2398 err = btrfs_run_sanity_tests();
2399 if (err)
2400 goto unregister_ioctl;
2401
2402 err = register_filesystem(&btrfs_fs_type);
2403 if (err)
2404 goto unregister_ioctl;
2405
2406 return 0;
2407
2408unregister_ioctl:
2409 btrfs_interface_exit();
2410free_end_io_wq:
2411 btrfs_end_io_wq_exit();
2412free_prelim_ref:
2413 btrfs_prelim_ref_exit();
2414free_delayed_ref:
2415 btrfs_delayed_ref_exit();
2416free_auto_defrag:
2417 btrfs_auto_defrag_exit();
2418free_delayed_inode:
2419 btrfs_delayed_inode_exit();
2420free_ordered_data:
2421 ordered_data_exit();
2422free_extent_map:
2423 extent_map_exit();
2424free_extent_io:
2425 extent_io_exit();
2426free_cachep:
2427 btrfs_destroy_cachep();
2428free_compress:
2429 btrfs_exit_compress();
2430 btrfs_exit_sysfs();
2431free_hash:
2432 btrfs_hash_exit();
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 btrfs_hash_exit();
2453}
2454
2455late_initcall(init_btrfs_fs);
2456module_exit(exit_btrfs_fs)
2457
2458MODULE_LICENSE("GPL");