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