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 <linux/swap.h>
32 #include "messages.h"
33 #include "delayed-inode.h"
34 #include "ctree.h"
35 #include "disk-io.h"
36 #include "transaction.h"
37 #include "btrfs_inode.h"
38 #include "direct-io.h"
39 #include "props.h"
40 #include "xattr.h"
41 #include "bio.h"
42 #include "export.h"
43 #include "compression.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
67 static const struct super_operations btrfs_super_ops;
68 static struct file_system_type btrfs_fs_type;
69
btrfs_put_super(struct super_block * sb)70 static 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. */
79 struct 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 long mount_opt;
87 unsigned long compress_type:4;
88 unsigned int compress_level;
89 refcount_t refs;
90 };
91
92 enum {
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 Opt_norecovery,
125
126 /* Rescue options */
127 Opt_rescue,
128 Opt_usebackuproot,
129 Opt_nologreplay,
130
131 /* Debugging options */
132 Opt_enospc_debug,
133 #ifdef CONFIG_BTRFS_DEBUG
134 Opt_fragment, Opt_fragment_data, Opt_fragment_metadata, Opt_fragment_all,
135 #endif
136 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
137 Opt_ref_verify,
138 #endif
139 Opt_err,
140 };
141
142 enum {
143 Opt_fatal_errors_panic,
144 Opt_fatal_errors_bug,
145 };
146
147 static const struct constant_table btrfs_parameter_fatal_errors[] = {
148 { "panic", Opt_fatal_errors_panic },
149 { "bug", Opt_fatal_errors_bug },
150 {}
151 };
152
153 enum {
154 Opt_discard_sync,
155 Opt_discard_async,
156 };
157
158 static const struct constant_table btrfs_parameter_discard[] = {
159 { "sync", Opt_discard_sync },
160 { "async", Opt_discard_async },
161 {}
162 };
163
164 enum {
165 Opt_space_cache_v1,
166 Opt_space_cache_v2,
167 };
168
169 static const struct constant_table btrfs_parameter_space_cache[] = {
170 { "v1", Opt_space_cache_v1 },
171 { "v2", Opt_space_cache_v2 },
172 {}
173 };
174
175 enum {
176 Opt_rescue_usebackuproot,
177 Opt_rescue_nologreplay,
178 Opt_rescue_ignorebadroots,
179 Opt_rescue_ignoredatacsums,
180 Opt_rescue_ignoremetacsums,
181 Opt_rescue_ignoresuperflags,
182 Opt_rescue_parameter_all,
183 };
184
185 static 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 { "ignoremetacsums", Opt_rescue_ignoremetacsums},
192 { "ignoresuperflags", Opt_rescue_ignoresuperflags},
193 { "idatacsums", Opt_rescue_ignoredatacsums },
194 { "imetacsums", Opt_rescue_ignoremetacsums},
195 { "isuperflags", Opt_rescue_ignoresuperflags},
196 { "all", Opt_rescue_parameter_all },
197 {}
198 };
199
200 #ifdef CONFIG_BTRFS_DEBUG
201 enum {
202 Opt_fragment_parameter_data,
203 Opt_fragment_parameter_metadata,
204 Opt_fragment_parameter_all,
205 };
206
207 static const struct constant_table btrfs_parameter_fragment[] = {
208 { "data", Opt_fragment_parameter_data },
209 { "metadata", Opt_fragment_parameter_metadata },
210 { "all", Opt_fragment_parameter_all },
211 {}
212 };
213 #endif
214
215 static const struct fs_parameter_spec btrfs_fs_parameters[] = {
216 fsparam_flag_no("acl", Opt_acl),
217 fsparam_flag_no("autodefrag", Opt_defrag),
218 fsparam_flag_no("barrier", Opt_barrier),
219 fsparam_flag("clear_cache", Opt_clear_cache),
220 fsparam_u32("commit", Opt_commit_interval),
221 fsparam_flag("compress", Opt_compress),
222 fsparam_string("compress", Opt_compress_type),
223 fsparam_flag("compress-force", Opt_compress_force),
224 fsparam_string("compress-force", Opt_compress_force_type),
225 fsparam_flag_no("datacow", Opt_datacow),
226 fsparam_flag_no("datasum", Opt_datasum),
227 fsparam_flag("degraded", Opt_degraded),
228 fsparam_string("device", Opt_device),
229 fsparam_flag_no("discard", Opt_discard),
230 fsparam_enum("discard", Opt_discard_mode, btrfs_parameter_discard),
231 fsparam_enum("fatal_errors", Opt_fatal_errors, btrfs_parameter_fatal_errors),
232 fsparam_flag_no("flushoncommit", Opt_flushoncommit),
233 fsparam_string("max_inline", Opt_max_inline),
234 fsparam_u32("metadata_ratio", Opt_ratio),
235 fsparam_flag("rescan_uuid_tree", Opt_rescan_uuid_tree),
236 fsparam_flag("skip_balance", Opt_skip_balance),
237 fsparam_flag_no("space_cache", Opt_space_cache),
238 fsparam_enum("space_cache", Opt_space_cache_version, btrfs_parameter_space_cache),
239 fsparam_flag_no("ssd", Opt_ssd),
240 fsparam_flag_no("ssd_spread", Opt_ssd_spread),
241 fsparam_string("subvol", Opt_subvol),
242 fsparam_flag("subvol=", Opt_subvol_empty),
243 fsparam_u64("subvolid", Opt_subvolid),
244 fsparam_u32("thread_pool", Opt_thread_pool),
245 fsparam_flag_no("treelog", Opt_treelog),
246 fsparam_flag("user_subvol_rm_allowed", Opt_user_subvol_rm_allowed),
247
248 /* Rescue options. */
249 fsparam_enum("rescue", Opt_rescue, btrfs_parameter_rescue),
250 /* Deprecated, with alias rescue=nologreplay */
251 __fsparam(NULL, "nologreplay", Opt_nologreplay, fs_param_deprecated, NULL),
252 /* Deprecated, with alias rescue=usebackuproot */
253 __fsparam(NULL, "usebackuproot", Opt_usebackuproot, fs_param_deprecated, NULL),
254 /* For compatibility only, alias for "rescue=nologreplay". */
255 fsparam_flag("norecovery", Opt_norecovery),
256
257 /* Debugging options. */
258 fsparam_flag_no("enospc_debug", Opt_enospc_debug),
259 #ifdef CONFIG_BTRFS_DEBUG
260 fsparam_enum("fragment", Opt_fragment, btrfs_parameter_fragment),
261 #endif
262 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
263 fsparam_flag("ref_verify", Opt_ref_verify),
264 #endif
265 {}
266 };
267
268 /* No support for restricting writes to btrfs devices yet... */
btrfs_open_mode(struct fs_context * fc)269 static inline blk_mode_t btrfs_open_mode(struct fs_context *fc)
270 {
271 return sb_open_mode(fc->sb_flags) & ~BLK_OPEN_RESTRICT_WRITES;
272 }
273
btrfs_parse_param(struct fs_context * fc,struct fs_parameter * param)274 static int btrfs_parse_param(struct fs_context *fc, struct fs_parameter *param)
275 {
276 struct btrfs_fs_context *ctx = fc->fs_private;
277 struct fs_parse_result result;
278 int opt;
279
280 opt = fs_parse(fc, btrfs_fs_parameters, param, &result);
281 if (opt < 0)
282 return opt;
283
284 switch (opt) {
285 case Opt_degraded:
286 btrfs_set_opt(ctx->mount_opt, DEGRADED);
287 break;
288 case Opt_subvol_empty:
289 /*
290 * This exists because we used to allow it on accident, so we're
291 * keeping it to maintain ABI. See 37becec95ac3 ("Btrfs: allow
292 * empty subvol= again").
293 */
294 break;
295 case Opt_subvol:
296 kfree(ctx->subvol_name);
297 ctx->subvol_name = kstrdup(param->string, GFP_KERNEL);
298 if (!ctx->subvol_name)
299 return -ENOMEM;
300 break;
301 case Opt_subvolid:
302 ctx->subvol_objectid = result.uint_64;
303
304 /* subvolid=0 means give me the original fs_tree. */
305 if (!ctx->subvol_objectid)
306 ctx->subvol_objectid = BTRFS_FS_TREE_OBJECTID;
307 break;
308 case Opt_device: {
309 struct btrfs_device *device;
310 blk_mode_t mode = btrfs_open_mode(fc);
311
312 mutex_lock(&uuid_mutex);
313 device = btrfs_scan_one_device(param->string, mode, false);
314 mutex_unlock(&uuid_mutex);
315 if (IS_ERR(device))
316 return PTR_ERR(device);
317 break;
318 }
319 case Opt_datasum:
320 if (result.negated) {
321 btrfs_set_opt(ctx->mount_opt, NODATASUM);
322 } else {
323 btrfs_clear_opt(ctx->mount_opt, NODATACOW);
324 btrfs_clear_opt(ctx->mount_opt, NODATASUM);
325 }
326 break;
327 case Opt_datacow:
328 if (result.negated) {
329 btrfs_clear_opt(ctx->mount_opt, COMPRESS);
330 btrfs_clear_opt(ctx->mount_opt, FORCE_COMPRESS);
331 btrfs_set_opt(ctx->mount_opt, NODATACOW);
332 btrfs_set_opt(ctx->mount_opt, NODATASUM);
333 } else {
334 btrfs_clear_opt(ctx->mount_opt, NODATACOW);
335 }
336 break;
337 case Opt_compress_force:
338 case Opt_compress_force_type:
339 btrfs_set_opt(ctx->mount_opt, FORCE_COMPRESS);
340 fallthrough;
341 case Opt_compress:
342 case Opt_compress_type:
343 /*
344 * Provide the same semantics as older kernels that don't use fs
345 * context, specifying the "compress" option clears
346 * "force-compress" without the need to pass
347 * "compress-force=[no|none]" before specifying "compress".
348 */
349 if (opt != Opt_compress_force && opt != Opt_compress_force_type)
350 btrfs_clear_opt(ctx->mount_opt, FORCE_COMPRESS);
351
352 if (opt == Opt_compress || opt == Opt_compress_force) {
353 ctx->compress_type = BTRFS_COMPRESS_ZLIB;
354 ctx->compress_level = BTRFS_ZLIB_DEFAULT_LEVEL;
355 btrfs_set_opt(ctx->mount_opt, COMPRESS);
356 btrfs_clear_opt(ctx->mount_opt, NODATACOW);
357 btrfs_clear_opt(ctx->mount_opt, NODATASUM);
358 } else if (strncmp(param->string, "zlib", 4) == 0) {
359 ctx->compress_type = BTRFS_COMPRESS_ZLIB;
360 ctx->compress_level =
361 btrfs_compress_str2level(BTRFS_COMPRESS_ZLIB,
362 param->string + 4);
363 btrfs_set_opt(ctx->mount_opt, COMPRESS);
364 btrfs_clear_opt(ctx->mount_opt, NODATACOW);
365 btrfs_clear_opt(ctx->mount_opt, NODATASUM);
366 } else if (strncmp(param->string, "lzo", 3) == 0) {
367 ctx->compress_type = BTRFS_COMPRESS_LZO;
368 ctx->compress_level = 0;
369 btrfs_set_opt(ctx->mount_opt, COMPRESS);
370 btrfs_clear_opt(ctx->mount_opt, NODATACOW);
371 btrfs_clear_opt(ctx->mount_opt, NODATASUM);
372 } else if (strncmp(param->string, "zstd", 4) == 0) {
373 ctx->compress_type = BTRFS_COMPRESS_ZSTD;
374 ctx->compress_level =
375 btrfs_compress_str2level(BTRFS_COMPRESS_ZSTD,
376 param->string + 4);
377 btrfs_set_opt(ctx->mount_opt, COMPRESS);
378 btrfs_clear_opt(ctx->mount_opt, NODATACOW);
379 btrfs_clear_opt(ctx->mount_opt, NODATASUM);
380 } else if (strncmp(param->string, "no", 2) == 0) {
381 ctx->compress_level = 0;
382 ctx->compress_type = 0;
383 btrfs_clear_opt(ctx->mount_opt, COMPRESS);
384 btrfs_clear_opt(ctx->mount_opt, FORCE_COMPRESS);
385 } else {
386 btrfs_err(NULL, "unrecognized compression value %s",
387 param->string);
388 return -EINVAL;
389 }
390 break;
391 case Opt_ssd:
392 if (result.negated) {
393 btrfs_set_opt(ctx->mount_opt, NOSSD);
394 btrfs_clear_opt(ctx->mount_opt, SSD);
395 btrfs_clear_opt(ctx->mount_opt, SSD_SPREAD);
396 } else {
397 btrfs_set_opt(ctx->mount_opt, SSD);
398 btrfs_clear_opt(ctx->mount_opt, NOSSD);
399 }
400 break;
401 case Opt_ssd_spread:
402 if (result.negated) {
403 btrfs_clear_opt(ctx->mount_opt, SSD_SPREAD);
404 } else {
405 btrfs_set_opt(ctx->mount_opt, SSD);
406 btrfs_set_opt(ctx->mount_opt, SSD_SPREAD);
407 btrfs_clear_opt(ctx->mount_opt, NOSSD);
408 }
409 break;
410 case Opt_barrier:
411 if (result.negated)
412 btrfs_set_opt(ctx->mount_opt, NOBARRIER);
413 else
414 btrfs_clear_opt(ctx->mount_opt, NOBARRIER);
415 break;
416 case Opt_thread_pool:
417 if (result.uint_32 == 0) {
418 btrfs_err(NULL, "invalid value 0 for thread_pool");
419 return -EINVAL;
420 }
421 ctx->thread_pool_size = result.uint_32;
422 break;
423 case Opt_max_inline:
424 ctx->max_inline = memparse(param->string, NULL);
425 break;
426 case Opt_acl:
427 if (result.negated) {
428 fc->sb_flags &= ~SB_POSIXACL;
429 } else {
430 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
431 fc->sb_flags |= SB_POSIXACL;
432 #else
433 btrfs_err(NULL, "support for ACL not compiled in");
434 return -EINVAL;
435 #endif
436 }
437 /*
438 * VFS limits the ability to toggle ACL on and off via remount,
439 * despite every file system allowing this. This seems to be
440 * an oversight since we all do, but it'll fail if we're
441 * remounting. So don't set the mask here, we'll check it in
442 * btrfs_reconfigure and do the toggling ourselves.
443 */
444 if (fc->purpose != FS_CONTEXT_FOR_RECONFIGURE)
445 fc->sb_flags_mask |= SB_POSIXACL;
446 break;
447 case Opt_treelog:
448 if (result.negated)
449 btrfs_set_opt(ctx->mount_opt, NOTREELOG);
450 else
451 btrfs_clear_opt(ctx->mount_opt, NOTREELOG);
452 break;
453 case Opt_nologreplay:
454 btrfs_warn(NULL,
455 "'nologreplay' is deprecated, use 'rescue=nologreplay' instead");
456 btrfs_set_opt(ctx->mount_opt, NOLOGREPLAY);
457 break;
458 case Opt_norecovery:
459 btrfs_info(NULL,
460 "'norecovery' is for compatibility only, recommended to use 'rescue=nologreplay'");
461 btrfs_set_opt(ctx->mount_opt, NOLOGREPLAY);
462 break;
463 case Opt_flushoncommit:
464 if (result.negated)
465 btrfs_clear_opt(ctx->mount_opt, FLUSHONCOMMIT);
466 else
467 btrfs_set_opt(ctx->mount_opt, FLUSHONCOMMIT);
468 break;
469 case Opt_ratio:
470 ctx->metadata_ratio = result.uint_32;
471 break;
472 case Opt_discard:
473 if (result.negated) {
474 btrfs_clear_opt(ctx->mount_opt, DISCARD_SYNC);
475 btrfs_clear_opt(ctx->mount_opt, DISCARD_ASYNC);
476 btrfs_set_opt(ctx->mount_opt, NODISCARD);
477 } else {
478 btrfs_set_opt(ctx->mount_opt, DISCARD_SYNC);
479 btrfs_clear_opt(ctx->mount_opt, DISCARD_ASYNC);
480 }
481 break;
482 case Opt_discard_mode:
483 switch (result.uint_32) {
484 case Opt_discard_sync:
485 btrfs_clear_opt(ctx->mount_opt, DISCARD_ASYNC);
486 btrfs_set_opt(ctx->mount_opt, DISCARD_SYNC);
487 break;
488 case Opt_discard_async:
489 btrfs_clear_opt(ctx->mount_opt, DISCARD_SYNC);
490 btrfs_set_opt(ctx->mount_opt, DISCARD_ASYNC);
491 break;
492 default:
493 btrfs_err(NULL, "unrecognized discard mode value %s",
494 param->key);
495 return -EINVAL;
496 }
497 btrfs_clear_opt(ctx->mount_opt, NODISCARD);
498 break;
499 case Opt_space_cache:
500 if (result.negated) {
501 btrfs_set_opt(ctx->mount_opt, NOSPACECACHE);
502 btrfs_clear_opt(ctx->mount_opt, SPACE_CACHE);
503 btrfs_clear_opt(ctx->mount_opt, FREE_SPACE_TREE);
504 } else {
505 btrfs_clear_opt(ctx->mount_opt, FREE_SPACE_TREE);
506 btrfs_set_opt(ctx->mount_opt, SPACE_CACHE);
507 }
508 break;
509 case Opt_space_cache_version:
510 switch (result.uint_32) {
511 case Opt_space_cache_v1:
512 btrfs_set_opt(ctx->mount_opt, SPACE_CACHE);
513 btrfs_clear_opt(ctx->mount_opt, FREE_SPACE_TREE);
514 break;
515 case Opt_space_cache_v2:
516 btrfs_clear_opt(ctx->mount_opt, SPACE_CACHE);
517 btrfs_set_opt(ctx->mount_opt, FREE_SPACE_TREE);
518 break;
519 default:
520 btrfs_err(NULL, "unrecognized space_cache value %s",
521 param->key);
522 return -EINVAL;
523 }
524 break;
525 case Opt_rescan_uuid_tree:
526 btrfs_set_opt(ctx->mount_opt, RESCAN_UUID_TREE);
527 break;
528 case Opt_clear_cache:
529 btrfs_set_opt(ctx->mount_opt, CLEAR_CACHE);
530 break;
531 case Opt_user_subvol_rm_allowed:
532 btrfs_set_opt(ctx->mount_opt, USER_SUBVOL_RM_ALLOWED);
533 break;
534 case Opt_enospc_debug:
535 if (result.negated)
536 btrfs_clear_opt(ctx->mount_opt, ENOSPC_DEBUG);
537 else
538 btrfs_set_opt(ctx->mount_opt, ENOSPC_DEBUG);
539 break;
540 case Opt_defrag:
541 if (result.negated)
542 btrfs_clear_opt(ctx->mount_opt, AUTO_DEFRAG);
543 else
544 btrfs_set_opt(ctx->mount_opt, AUTO_DEFRAG);
545 break;
546 case Opt_usebackuproot:
547 btrfs_warn(NULL,
548 "'usebackuproot' is deprecated, use 'rescue=usebackuproot' instead");
549 btrfs_set_opt(ctx->mount_opt, USEBACKUPROOT);
550
551 /* If we're loading the backup roots we can't trust the space cache. */
552 btrfs_set_opt(ctx->mount_opt, CLEAR_CACHE);
553 break;
554 case Opt_skip_balance:
555 btrfs_set_opt(ctx->mount_opt, SKIP_BALANCE);
556 break;
557 case Opt_fatal_errors:
558 switch (result.uint_32) {
559 case Opt_fatal_errors_panic:
560 btrfs_set_opt(ctx->mount_opt, PANIC_ON_FATAL_ERROR);
561 break;
562 case Opt_fatal_errors_bug:
563 btrfs_clear_opt(ctx->mount_opt, PANIC_ON_FATAL_ERROR);
564 break;
565 default:
566 btrfs_err(NULL, "unrecognized fatal_errors value %s",
567 param->key);
568 return -EINVAL;
569 }
570 break;
571 case Opt_commit_interval:
572 ctx->commit_interval = result.uint_32;
573 if (ctx->commit_interval == 0)
574 ctx->commit_interval = BTRFS_DEFAULT_COMMIT_INTERVAL;
575 break;
576 case Opt_rescue:
577 switch (result.uint_32) {
578 case Opt_rescue_usebackuproot:
579 btrfs_set_opt(ctx->mount_opt, USEBACKUPROOT);
580 break;
581 case Opt_rescue_nologreplay:
582 btrfs_set_opt(ctx->mount_opt, NOLOGREPLAY);
583 break;
584 case Opt_rescue_ignorebadroots:
585 btrfs_set_opt(ctx->mount_opt, IGNOREBADROOTS);
586 break;
587 case Opt_rescue_ignoredatacsums:
588 btrfs_set_opt(ctx->mount_opt, IGNOREDATACSUMS);
589 break;
590 case Opt_rescue_ignoremetacsums:
591 btrfs_set_opt(ctx->mount_opt, IGNOREMETACSUMS);
592 break;
593 case Opt_rescue_ignoresuperflags:
594 btrfs_set_opt(ctx->mount_opt, IGNORESUPERFLAGS);
595 break;
596 case Opt_rescue_parameter_all:
597 btrfs_set_opt(ctx->mount_opt, IGNOREDATACSUMS);
598 btrfs_set_opt(ctx->mount_opt, IGNOREMETACSUMS);
599 btrfs_set_opt(ctx->mount_opt, IGNORESUPERFLAGS);
600 btrfs_set_opt(ctx->mount_opt, IGNOREBADROOTS);
601 btrfs_set_opt(ctx->mount_opt, NOLOGREPLAY);
602 break;
603 default:
604 btrfs_info(NULL, "unrecognized rescue option '%s'",
605 param->key);
606 return -EINVAL;
607 }
608 break;
609 #ifdef CONFIG_BTRFS_DEBUG
610 case Opt_fragment:
611 switch (result.uint_32) {
612 case Opt_fragment_parameter_all:
613 btrfs_set_opt(ctx->mount_opt, FRAGMENT_DATA);
614 btrfs_set_opt(ctx->mount_opt, FRAGMENT_METADATA);
615 break;
616 case Opt_fragment_parameter_metadata:
617 btrfs_set_opt(ctx->mount_opt, FRAGMENT_METADATA);
618 break;
619 case Opt_fragment_parameter_data:
620 btrfs_set_opt(ctx->mount_opt, FRAGMENT_DATA);
621 break;
622 default:
623 btrfs_info(NULL, "unrecognized fragment option '%s'",
624 param->key);
625 return -EINVAL;
626 }
627 break;
628 #endif
629 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
630 case Opt_ref_verify:
631 btrfs_set_opt(ctx->mount_opt, REF_VERIFY);
632 break;
633 #endif
634 default:
635 btrfs_err(NULL, "unrecognized mount option '%s'", param->key);
636 return -EINVAL;
637 }
638
639 return 0;
640 }
641
642 /*
643 * Some options only have meaning at mount time and shouldn't persist across
644 * remounts, or be displayed. Clear these at the end of mount and remount code
645 * paths.
646 */
btrfs_clear_oneshot_options(struct btrfs_fs_info * fs_info)647 static void btrfs_clear_oneshot_options(struct btrfs_fs_info *fs_info)
648 {
649 btrfs_clear_opt(fs_info->mount_opt, USEBACKUPROOT);
650 btrfs_clear_opt(fs_info->mount_opt, CLEAR_CACHE);
651 btrfs_clear_opt(fs_info->mount_opt, NOSPACECACHE);
652 }
653
check_ro_option(const struct btrfs_fs_info * fs_info,unsigned long long mount_opt,unsigned long long opt,const char * opt_name)654 static bool check_ro_option(const struct btrfs_fs_info *fs_info,
655 unsigned long long mount_opt, unsigned long long opt,
656 const char *opt_name)
657 {
658 if (mount_opt & opt) {
659 btrfs_err(fs_info, "%s must be used with ro mount option",
660 opt_name);
661 return true;
662 }
663 return false;
664 }
665
btrfs_check_options(const struct btrfs_fs_info * info,unsigned long long * mount_opt,unsigned long flags)666 bool btrfs_check_options(const struct btrfs_fs_info *info,
667 unsigned long long *mount_opt,
668 unsigned long flags)
669 {
670 bool ret = true;
671
672 if (!(flags & SB_RDONLY) &&
673 (check_ro_option(info, *mount_opt, BTRFS_MOUNT_NOLOGREPLAY, "nologreplay") ||
674 check_ro_option(info, *mount_opt, BTRFS_MOUNT_IGNOREBADROOTS, "ignorebadroots") ||
675 check_ro_option(info, *mount_opt, BTRFS_MOUNT_IGNOREDATACSUMS, "ignoredatacsums") ||
676 check_ro_option(info, *mount_opt, BTRFS_MOUNT_IGNOREMETACSUMS, "ignoremetacsums") ||
677 check_ro_option(info, *mount_opt, BTRFS_MOUNT_IGNORESUPERFLAGS, "ignoresuperflags")))
678 ret = false;
679
680 if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE) &&
681 !btrfs_raw_test_opt(*mount_opt, FREE_SPACE_TREE) &&
682 !btrfs_raw_test_opt(*mount_opt, CLEAR_CACHE)) {
683 btrfs_err(info, "cannot disable free-space-tree");
684 ret = false;
685 }
686 if (btrfs_fs_compat_ro(info, BLOCK_GROUP_TREE) &&
687 !btrfs_raw_test_opt(*mount_opt, FREE_SPACE_TREE)) {
688 btrfs_err(info, "cannot disable free-space-tree with block-group-tree feature");
689 ret = false;
690 }
691
692 if (btrfs_check_mountopts_zoned(info, mount_opt))
693 ret = false;
694
695 if (!test_bit(BTRFS_FS_STATE_REMOUNTING, &info->fs_state)) {
696 if (btrfs_raw_test_opt(*mount_opt, SPACE_CACHE)) {
697 btrfs_info(info, "disk space caching is enabled");
698 btrfs_warn(info,
699 "space cache v1 is being deprecated and will be removed in a future release, please use -o space_cache=v2");
700 }
701 if (btrfs_raw_test_opt(*mount_opt, FREE_SPACE_TREE))
702 btrfs_info(info, "using free-space-tree");
703 }
704
705 return ret;
706 }
707
708 /*
709 * This is subtle, we only call this during open_ctree(). We need to pre-load
710 * the mount options with the on-disk settings. Before the new mount API took
711 * effect we would do this on mount and remount. With the new mount API we'll
712 * only do this on the initial mount.
713 *
714 * This isn't a change in behavior, because we're using the current state of the
715 * file system to set the current mount options. If you mounted with special
716 * options to disable these features and then remounted we wouldn't revert the
717 * settings, because mounting without these features cleared the on-disk
718 * settings, so this being called on re-mount is not needed.
719 */
btrfs_set_free_space_cache_settings(struct btrfs_fs_info * fs_info)720 void btrfs_set_free_space_cache_settings(struct btrfs_fs_info *fs_info)
721 {
722 if (fs_info->sectorsize < PAGE_SIZE) {
723 btrfs_clear_opt(fs_info->mount_opt, SPACE_CACHE);
724 if (!btrfs_test_opt(fs_info, FREE_SPACE_TREE)) {
725 btrfs_info(fs_info,
726 "forcing free space tree for sector size %u with page size %lu",
727 fs_info->sectorsize, PAGE_SIZE);
728 btrfs_set_opt(fs_info->mount_opt, FREE_SPACE_TREE);
729 }
730 }
731
732 /*
733 * At this point our mount options are populated, so we only mess with
734 * these settings if we don't have any settings already.
735 */
736 if (btrfs_test_opt(fs_info, FREE_SPACE_TREE))
737 return;
738
739 if (btrfs_is_zoned(fs_info) &&
740 btrfs_free_space_cache_v1_active(fs_info)) {
741 btrfs_info(fs_info, "zoned: clearing existing space cache");
742 btrfs_set_super_cache_generation(fs_info->super_copy, 0);
743 return;
744 }
745
746 if (btrfs_test_opt(fs_info, SPACE_CACHE))
747 return;
748
749 if (btrfs_test_opt(fs_info, NOSPACECACHE))
750 return;
751
752 /*
753 * At this point we don't have explicit options set by the user, set
754 * them ourselves based on the state of the file system.
755 */
756 if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
757 btrfs_set_opt(fs_info->mount_opt, FREE_SPACE_TREE);
758 else if (btrfs_free_space_cache_v1_active(fs_info))
759 btrfs_set_opt(fs_info->mount_opt, SPACE_CACHE);
760 }
761
set_device_specific_options(struct btrfs_fs_info * fs_info)762 static void set_device_specific_options(struct btrfs_fs_info *fs_info)
763 {
764 if (!btrfs_test_opt(fs_info, NOSSD) &&
765 !fs_info->fs_devices->rotating)
766 btrfs_set_opt(fs_info->mount_opt, SSD);
767
768 /*
769 * For devices supporting discard turn on discard=async automatically,
770 * unless it's already set or disabled. This could be turned off by
771 * nodiscard for the same mount.
772 *
773 * The zoned mode piggy backs on the discard functionality for
774 * resetting a zone. There is no reason to delay the zone reset as it is
775 * fast enough. So, do not enable async discard for zoned mode.
776 */
777 if (!(btrfs_test_opt(fs_info, DISCARD_SYNC) ||
778 btrfs_test_opt(fs_info, DISCARD_ASYNC) ||
779 btrfs_test_opt(fs_info, NODISCARD)) &&
780 fs_info->fs_devices->discardable &&
781 !btrfs_is_zoned(fs_info))
782 btrfs_set_opt(fs_info->mount_opt, DISCARD_ASYNC);
783 }
784
btrfs_get_subvol_name_from_objectid(struct btrfs_fs_info * fs_info,u64 subvol_objectid)785 char *btrfs_get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
786 u64 subvol_objectid)
787 {
788 struct btrfs_root *root = fs_info->tree_root;
789 struct btrfs_root *fs_root = NULL;
790 struct btrfs_root_ref *root_ref;
791 struct btrfs_inode_ref *inode_ref;
792 struct btrfs_key key;
793 struct btrfs_path *path = NULL;
794 char *name = NULL, *ptr;
795 u64 dirid;
796 int len;
797 int ret;
798
799 path = btrfs_alloc_path();
800 if (!path) {
801 ret = -ENOMEM;
802 goto err;
803 }
804
805 name = kmalloc(PATH_MAX, GFP_KERNEL);
806 if (!name) {
807 ret = -ENOMEM;
808 goto err;
809 }
810 ptr = name + PATH_MAX - 1;
811 ptr[0] = '\0';
812
813 /*
814 * Walk up the subvolume trees in the tree of tree roots by root
815 * backrefs until we hit the top-level subvolume.
816 */
817 while (subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
818 key.objectid = subvol_objectid;
819 key.type = BTRFS_ROOT_BACKREF_KEY;
820 key.offset = (u64)-1;
821
822 ret = btrfs_search_backwards(root, &key, path);
823 if (ret < 0) {
824 goto err;
825 } else if (ret > 0) {
826 ret = -ENOENT;
827 goto err;
828 }
829
830 subvol_objectid = key.offset;
831
832 root_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
833 struct btrfs_root_ref);
834 len = btrfs_root_ref_name_len(path->nodes[0], root_ref);
835 ptr -= len + 1;
836 if (ptr < name) {
837 ret = -ENAMETOOLONG;
838 goto err;
839 }
840 read_extent_buffer(path->nodes[0], ptr + 1,
841 (unsigned long)(root_ref + 1), len);
842 ptr[0] = '/';
843 dirid = btrfs_root_ref_dirid(path->nodes[0], root_ref);
844 btrfs_release_path(path);
845
846 fs_root = btrfs_get_fs_root(fs_info, subvol_objectid, true);
847 if (IS_ERR(fs_root)) {
848 ret = PTR_ERR(fs_root);
849 fs_root = NULL;
850 goto err;
851 }
852
853 /*
854 * Walk up the filesystem tree by inode refs until we hit the
855 * root directory.
856 */
857 while (dirid != BTRFS_FIRST_FREE_OBJECTID) {
858 key.objectid = dirid;
859 key.type = BTRFS_INODE_REF_KEY;
860 key.offset = (u64)-1;
861
862 ret = btrfs_search_backwards(fs_root, &key, path);
863 if (ret < 0) {
864 goto err;
865 } else if (ret > 0) {
866 ret = -ENOENT;
867 goto err;
868 }
869
870 dirid = key.offset;
871
872 inode_ref = btrfs_item_ptr(path->nodes[0],
873 path->slots[0],
874 struct btrfs_inode_ref);
875 len = btrfs_inode_ref_name_len(path->nodes[0],
876 inode_ref);
877 ptr -= len + 1;
878 if (ptr < name) {
879 ret = -ENAMETOOLONG;
880 goto err;
881 }
882 read_extent_buffer(path->nodes[0], ptr + 1,
883 (unsigned long)(inode_ref + 1), len);
884 ptr[0] = '/';
885 btrfs_release_path(path);
886 }
887 btrfs_put_root(fs_root);
888 fs_root = NULL;
889 }
890
891 btrfs_free_path(path);
892 if (ptr == name + PATH_MAX - 1) {
893 name[0] = '/';
894 name[1] = '\0';
895 } else {
896 memmove(name, ptr, name + PATH_MAX - ptr);
897 }
898 return name;
899
900 err:
901 btrfs_put_root(fs_root);
902 btrfs_free_path(path);
903 kfree(name);
904 return ERR_PTR(ret);
905 }
906
get_default_subvol_objectid(struct btrfs_fs_info * fs_info,u64 * objectid)907 static int get_default_subvol_objectid(struct btrfs_fs_info *fs_info, u64 *objectid)
908 {
909 struct btrfs_root *root = fs_info->tree_root;
910 struct btrfs_dir_item *di;
911 struct btrfs_path *path;
912 struct btrfs_key location;
913 struct fscrypt_str name = FSTR_INIT("default", 7);
914 u64 dir_id;
915
916 path = btrfs_alloc_path();
917 if (!path)
918 return -ENOMEM;
919
920 /*
921 * Find the "default" dir item which points to the root item that we
922 * will mount by default if we haven't been given a specific subvolume
923 * to mount.
924 */
925 dir_id = btrfs_super_root_dir(fs_info->super_copy);
926 di = btrfs_lookup_dir_item(NULL, root, path, dir_id, &name, 0);
927 if (IS_ERR(di)) {
928 btrfs_free_path(path);
929 return PTR_ERR(di);
930 }
931 if (!di) {
932 /*
933 * Ok the default dir item isn't there. This is weird since
934 * it's always been there, but don't freak out, just try and
935 * mount the top-level subvolume.
936 */
937 btrfs_free_path(path);
938 *objectid = BTRFS_FS_TREE_OBJECTID;
939 return 0;
940 }
941
942 btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
943 btrfs_free_path(path);
944 *objectid = location.objectid;
945 return 0;
946 }
947
btrfs_fill_super(struct super_block * sb,struct btrfs_fs_devices * fs_devices,void * data)948 static int btrfs_fill_super(struct super_block *sb,
949 struct btrfs_fs_devices *fs_devices,
950 void *data)
951 {
952 struct inode *inode;
953 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
954 int err;
955
956 sb->s_maxbytes = MAX_LFS_FILESIZE;
957 sb->s_magic = BTRFS_SUPER_MAGIC;
958 sb->s_op = &btrfs_super_ops;
959 sb->s_d_op = &btrfs_dentry_operations;
960 sb->s_export_op = &btrfs_export_ops;
961 #ifdef CONFIG_FS_VERITY
962 sb->s_vop = &btrfs_verityops;
963 #endif
964 sb->s_xattr = btrfs_xattr_handlers;
965 sb->s_time_gran = 1;
966 sb->s_iflags |= SB_I_CGROUPWB;
967
968 err = super_setup_bdi(sb);
969 if (err) {
970 btrfs_err(fs_info, "super_setup_bdi failed");
971 return err;
972 }
973
974 err = open_ctree(sb, fs_devices, (char *)data);
975 if (err) {
976 btrfs_err(fs_info, "open_ctree failed");
977 return err;
978 }
979
980 inode = btrfs_iget(BTRFS_FIRST_FREE_OBJECTID, fs_info->fs_root);
981 if (IS_ERR(inode)) {
982 err = PTR_ERR(inode);
983 btrfs_handle_fs_error(fs_info, err, NULL);
984 goto fail_close;
985 }
986
987 sb->s_root = d_make_root(inode);
988 if (!sb->s_root) {
989 err = -ENOMEM;
990 goto fail_close;
991 }
992
993 sb->s_flags |= SB_ACTIVE;
994 return 0;
995
996 fail_close:
997 close_ctree(fs_info);
998 return err;
999 }
1000
btrfs_sync_fs(struct super_block * sb,int wait)1001 int btrfs_sync_fs(struct super_block *sb, int wait)
1002 {
1003 struct btrfs_trans_handle *trans;
1004 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1005 struct btrfs_root *root = fs_info->tree_root;
1006
1007 trace_btrfs_sync_fs(fs_info, wait);
1008
1009 if (!wait) {
1010 filemap_flush(fs_info->btree_inode->i_mapping);
1011 return 0;
1012 }
1013
1014 btrfs_wait_ordered_roots(fs_info, U64_MAX, NULL);
1015
1016 trans = btrfs_attach_transaction_barrier(root);
1017 if (IS_ERR(trans)) {
1018 /* no transaction, don't bother */
1019 if (PTR_ERR(trans) == -ENOENT) {
1020 /*
1021 * Exit unless we have some pending changes
1022 * that need to go through commit
1023 */
1024 if (!test_bit(BTRFS_FS_NEED_TRANS_COMMIT,
1025 &fs_info->flags))
1026 return 0;
1027 /*
1028 * A non-blocking test if the fs is frozen. We must not
1029 * start a new transaction here otherwise a deadlock
1030 * happens. The pending operations are delayed to the
1031 * next commit after thawing.
1032 */
1033 if (sb_start_write_trylock(sb))
1034 sb_end_write(sb);
1035 else
1036 return 0;
1037 trans = btrfs_start_transaction(root, 0);
1038 }
1039 if (IS_ERR(trans))
1040 return PTR_ERR(trans);
1041 }
1042 return btrfs_commit_transaction(trans);
1043 }
1044
print_rescue_option(struct seq_file * seq,const char * s,bool * printed)1045 static void print_rescue_option(struct seq_file *seq, const char *s, bool *printed)
1046 {
1047 seq_printf(seq, "%s%s", (*printed) ? ":" : ",rescue=", s);
1048 *printed = true;
1049 }
1050
btrfs_show_options(struct seq_file * seq,struct dentry * dentry)1051 static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
1052 {
1053 struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
1054 const char *compress_type;
1055 const char *subvol_name;
1056 bool printed = false;
1057
1058 if (btrfs_test_opt(info, DEGRADED))
1059 seq_puts(seq, ",degraded");
1060 if (btrfs_test_opt(info, NODATASUM))
1061 seq_puts(seq, ",nodatasum");
1062 if (btrfs_test_opt(info, NODATACOW))
1063 seq_puts(seq, ",nodatacow");
1064 if (btrfs_test_opt(info, NOBARRIER))
1065 seq_puts(seq, ",nobarrier");
1066 if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE)
1067 seq_printf(seq, ",max_inline=%llu", info->max_inline);
1068 if (info->thread_pool_size != min_t(unsigned long,
1069 num_online_cpus() + 2, 8))
1070 seq_printf(seq, ",thread_pool=%u", info->thread_pool_size);
1071 if (btrfs_test_opt(info, COMPRESS)) {
1072 compress_type = btrfs_compress_type2str(info->compress_type);
1073 if (btrfs_test_opt(info, FORCE_COMPRESS))
1074 seq_printf(seq, ",compress-force=%s", compress_type);
1075 else
1076 seq_printf(seq, ",compress=%s", compress_type);
1077 if (info->compress_level)
1078 seq_printf(seq, ":%d", info->compress_level);
1079 }
1080 if (btrfs_test_opt(info, NOSSD))
1081 seq_puts(seq, ",nossd");
1082 if (btrfs_test_opt(info, SSD_SPREAD))
1083 seq_puts(seq, ",ssd_spread");
1084 else if (btrfs_test_opt(info, SSD))
1085 seq_puts(seq, ",ssd");
1086 if (btrfs_test_opt(info, NOTREELOG))
1087 seq_puts(seq, ",notreelog");
1088 if (btrfs_test_opt(info, NOLOGREPLAY))
1089 print_rescue_option(seq, "nologreplay", &printed);
1090 if (btrfs_test_opt(info, USEBACKUPROOT))
1091 print_rescue_option(seq, "usebackuproot", &printed);
1092 if (btrfs_test_opt(info, IGNOREBADROOTS))
1093 print_rescue_option(seq, "ignorebadroots", &printed);
1094 if (btrfs_test_opt(info, IGNOREDATACSUMS))
1095 print_rescue_option(seq, "ignoredatacsums", &printed);
1096 if (btrfs_test_opt(info, IGNOREMETACSUMS))
1097 print_rescue_option(seq, "ignoremetacsums", &printed);
1098 if (btrfs_test_opt(info, IGNORESUPERFLAGS))
1099 print_rescue_option(seq, "ignoresuperflags", &printed);
1100 if (btrfs_test_opt(info, FLUSHONCOMMIT))
1101 seq_puts(seq, ",flushoncommit");
1102 if (btrfs_test_opt(info, DISCARD_SYNC))
1103 seq_puts(seq, ",discard");
1104 if (btrfs_test_opt(info, DISCARD_ASYNC))
1105 seq_puts(seq, ",discard=async");
1106 if (!(info->sb->s_flags & SB_POSIXACL))
1107 seq_puts(seq, ",noacl");
1108 if (btrfs_free_space_cache_v1_active(info))
1109 seq_puts(seq, ",space_cache");
1110 else if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE))
1111 seq_puts(seq, ",space_cache=v2");
1112 else
1113 seq_puts(seq, ",nospace_cache");
1114 if (btrfs_test_opt(info, RESCAN_UUID_TREE))
1115 seq_puts(seq, ",rescan_uuid_tree");
1116 if (btrfs_test_opt(info, CLEAR_CACHE))
1117 seq_puts(seq, ",clear_cache");
1118 if (btrfs_test_opt(info, USER_SUBVOL_RM_ALLOWED))
1119 seq_puts(seq, ",user_subvol_rm_allowed");
1120 if (btrfs_test_opt(info, ENOSPC_DEBUG))
1121 seq_puts(seq, ",enospc_debug");
1122 if (btrfs_test_opt(info, AUTO_DEFRAG))
1123 seq_puts(seq, ",autodefrag");
1124 if (btrfs_test_opt(info, SKIP_BALANCE))
1125 seq_puts(seq, ",skip_balance");
1126 if (info->metadata_ratio)
1127 seq_printf(seq, ",metadata_ratio=%u", info->metadata_ratio);
1128 if (btrfs_test_opt(info, PANIC_ON_FATAL_ERROR))
1129 seq_puts(seq, ",fatal_errors=panic");
1130 if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL)
1131 seq_printf(seq, ",commit=%u", info->commit_interval);
1132 #ifdef CONFIG_BTRFS_DEBUG
1133 if (btrfs_test_opt(info, FRAGMENT_DATA))
1134 seq_puts(seq, ",fragment=data");
1135 if (btrfs_test_opt(info, FRAGMENT_METADATA))
1136 seq_puts(seq, ",fragment=metadata");
1137 #endif
1138 if (btrfs_test_opt(info, REF_VERIFY))
1139 seq_puts(seq, ",ref_verify");
1140 seq_printf(seq, ",subvolid=%llu", btrfs_root_id(BTRFS_I(d_inode(dentry))->root));
1141 subvol_name = btrfs_get_subvol_name_from_objectid(info,
1142 btrfs_root_id(BTRFS_I(d_inode(dentry))->root));
1143 if (!IS_ERR(subvol_name)) {
1144 seq_puts(seq, ",subvol=");
1145 seq_escape(seq, subvol_name, " \t\n\\");
1146 kfree(subvol_name);
1147 }
1148 return 0;
1149 }
1150
1151 /*
1152 * subvolumes are identified by ino 256
1153 */
is_subvolume_inode(struct inode * inode)1154 static inline int is_subvolume_inode(struct inode *inode)
1155 {
1156 if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
1157 return 1;
1158 return 0;
1159 }
1160
mount_subvol(const char * subvol_name,u64 subvol_objectid,struct vfsmount * mnt)1161 static struct dentry *mount_subvol(const char *subvol_name, u64 subvol_objectid,
1162 struct vfsmount *mnt)
1163 {
1164 struct dentry *root;
1165 int ret;
1166
1167 if (!subvol_name) {
1168 if (!subvol_objectid) {
1169 ret = get_default_subvol_objectid(btrfs_sb(mnt->mnt_sb),
1170 &subvol_objectid);
1171 if (ret) {
1172 root = ERR_PTR(ret);
1173 goto out;
1174 }
1175 }
1176 subvol_name = btrfs_get_subvol_name_from_objectid(
1177 btrfs_sb(mnt->mnt_sb), subvol_objectid);
1178 if (IS_ERR(subvol_name)) {
1179 root = ERR_CAST(subvol_name);
1180 subvol_name = NULL;
1181 goto out;
1182 }
1183
1184 }
1185
1186 root = mount_subtree(mnt, subvol_name);
1187 /* mount_subtree() drops our reference on the vfsmount. */
1188 mnt = NULL;
1189
1190 if (!IS_ERR(root)) {
1191 struct super_block *s = root->d_sb;
1192 struct btrfs_fs_info *fs_info = btrfs_sb(s);
1193 struct inode *root_inode = d_inode(root);
1194 u64 root_objectid = btrfs_root_id(BTRFS_I(root_inode)->root);
1195
1196 ret = 0;
1197 if (!is_subvolume_inode(root_inode)) {
1198 btrfs_err(fs_info, "'%s' is not a valid subvolume",
1199 subvol_name);
1200 ret = -EINVAL;
1201 }
1202 if (subvol_objectid && root_objectid != subvol_objectid) {
1203 /*
1204 * This will also catch a race condition where a
1205 * subvolume which was passed by ID is renamed and
1206 * another subvolume is renamed over the old location.
1207 */
1208 btrfs_err(fs_info,
1209 "subvol '%s' does not match subvolid %llu",
1210 subvol_name, subvol_objectid);
1211 ret = -EINVAL;
1212 }
1213 if (ret) {
1214 dput(root);
1215 root = ERR_PTR(ret);
1216 deactivate_locked_super(s);
1217 }
1218 }
1219
1220 out:
1221 mntput(mnt);
1222 kfree(subvol_name);
1223 return root;
1224 }
1225
btrfs_resize_thread_pool(struct btrfs_fs_info * fs_info,u32 new_pool_size,u32 old_pool_size)1226 static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
1227 u32 new_pool_size, u32 old_pool_size)
1228 {
1229 if (new_pool_size == old_pool_size)
1230 return;
1231
1232 fs_info->thread_pool_size = new_pool_size;
1233
1234 btrfs_info(fs_info, "resize thread pool %d -> %d",
1235 old_pool_size, new_pool_size);
1236
1237 btrfs_workqueue_set_max(fs_info->workers, new_pool_size);
1238 btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size);
1239 btrfs_workqueue_set_max(fs_info->caching_workers, new_pool_size);
1240 workqueue_set_max_active(fs_info->endio_workers, new_pool_size);
1241 workqueue_set_max_active(fs_info->endio_meta_workers, new_pool_size);
1242 btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size);
1243 btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
1244 btrfs_workqueue_set_max(fs_info->delayed_workers, new_pool_size);
1245 }
1246
btrfs_remount_begin(struct btrfs_fs_info * fs_info,unsigned long long old_opts,int flags)1247 static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info,
1248 unsigned long long old_opts, int flags)
1249 {
1250 if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1251 (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1252 (flags & SB_RDONLY))) {
1253 /* wait for any defraggers to finish */
1254 wait_event(fs_info->transaction_wait,
1255 (atomic_read(&fs_info->defrag_running) == 0));
1256 if (flags & SB_RDONLY)
1257 sync_filesystem(fs_info->sb);
1258 }
1259 }
1260
btrfs_remount_cleanup(struct btrfs_fs_info * fs_info,unsigned long long old_opts)1261 static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
1262 unsigned long long old_opts)
1263 {
1264 const bool cache_opt = btrfs_test_opt(fs_info, SPACE_CACHE);
1265
1266 /*
1267 * We need to cleanup all defragable inodes if the autodefragment is
1268 * close or the filesystem is read only.
1269 */
1270 if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1271 (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) || sb_rdonly(fs_info->sb))) {
1272 btrfs_cleanup_defrag_inodes(fs_info);
1273 }
1274
1275 /* If we toggled discard async */
1276 if (!btrfs_raw_test_opt(old_opts, DISCARD_ASYNC) &&
1277 btrfs_test_opt(fs_info, DISCARD_ASYNC))
1278 btrfs_discard_resume(fs_info);
1279 else if (btrfs_raw_test_opt(old_opts, DISCARD_ASYNC) &&
1280 !btrfs_test_opt(fs_info, DISCARD_ASYNC))
1281 btrfs_discard_cleanup(fs_info);
1282
1283 /* If we toggled space cache */
1284 if (cache_opt != btrfs_free_space_cache_v1_active(fs_info))
1285 btrfs_set_free_space_cache_v1_active(fs_info, cache_opt);
1286 }
1287
btrfs_remount_rw(struct btrfs_fs_info * fs_info)1288 static int btrfs_remount_rw(struct btrfs_fs_info *fs_info)
1289 {
1290 int ret;
1291
1292 if (BTRFS_FS_ERROR(fs_info)) {
1293 btrfs_err(fs_info,
1294 "remounting read-write after error is not allowed");
1295 return -EINVAL;
1296 }
1297
1298 if (fs_info->fs_devices->rw_devices == 0)
1299 return -EACCES;
1300
1301 if (!btrfs_check_rw_degradable(fs_info, NULL)) {
1302 btrfs_warn(fs_info,
1303 "too many missing devices, writable remount is not allowed");
1304 return -EACCES;
1305 }
1306
1307 if (btrfs_super_log_root(fs_info->super_copy) != 0) {
1308 btrfs_warn(fs_info,
1309 "mount required to replay tree-log, cannot remount read-write");
1310 return -EINVAL;
1311 }
1312
1313 /*
1314 * NOTE: when remounting with a change that does writes, don't put it
1315 * anywhere above this point, as we are not sure to be safe to write
1316 * until we pass the above checks.
1317 */
1318 ret = btrfs_start_pre_rw_mount(fs_info);
1319 if (ret)
1320 return ret;
1321
1322 btrfs_clear_sb_rdonly(fs_info->sb);
1323
1324 set_bit(BTRFS_FS_OPEN, &fs_info->flags);
1325
1326 /*
1327 * If we've gone from readonly -> read-write, we need to get our
1328 * sync/async discard lists in the right state.
1329 */
1330 btrfs_discard_resume(fs_info);
1331
1332 return 0;
1333 }
1334
btrfs_remount_ro(struct btrfs_fs_info * fs_info)1335 static int btrfs_remount_ro(struct btrfs_fs_info *fs_info)
1336 {
1337 /*
1338 * This also happens on 'umount -rf' or on shutdown, when the
1339 * filesystem is busy.
1340 */
1341 cancel_work_sync(&fs_info->async_reclaim_work);
1342 cancel_work_sync(&fs_info->async_data_reclaim_work);
1343
1344 btrfs_discard_cleanup(fs_info);
1345
1346 /* Wait for the uuid_scan task to finish */
1347 down(&fs_info->uuid_tree_rescan_sem);
1348 /* Avoid complains from lockdep et al. */
1349 up(&fs_info->uuid_tree_rescan_sem);
1350
1351 btrfs_set_sb_rdonly(fs_info->sb);
1352
1353 /*
1354 * Setting SB_RDONLY will put the cleaner thread to sleep at the next
1355 * loop if it's already active. If it's already asleep, we'll leave
1356 * unused block groups on disk until we're mounted read-write again
1357 * unless we clean them up here.
1358 */
1359 btrfs_delete_unused_bgs(fs_info);
1360
1361 /*
1362 * The cleaner task could be already running before we set the flag
1363 * BTRFS_FS_STATE_RO (and SB_RDONLY in the superblock). We must make
1364 * sure that after we finish the remount, i.e. after we call
1365 * btrfs_commit_super(), the cleaner can no longer start a transaction
1366 * - either because it was dropping a dead root, running delayed iputs
1367 * or deleting an unused block group (the cleaner picked a block
1368 * group from the list of unused block groups before we were able to
1369 * in the previous call to btrfs_delete_unused_bgs()).
1370 */
1371 wait_on_bit(&fs_info->flags, BTRFS_FS_CLEANER_RUNNING, TASK_UNINTERRUPTIBLE);
1372
1373 /*
1374 * We've set the superblock to RO mode, so we might have made the
1375 * cleaner task sleep without running all pending delayed iputs. Go
1376 * through all the delayed iputs here, so that if an unmount happens
1377 * without remounting RW we don't end up at finishing close_ctree()
1378 * with a non-empty list of delayed iputs.
1379 */
1380 btrfs_run_delayed_iputs(fs_info);
1381
1382 btrfs_dev_replace_suspend_for_unmount(fs_info);
1383 btrfs_scrub_cancel(fs_info);
1384 btrfs_pause_balance(fs_info);
1385
1386 /*
1387 * Pause the qgroup rescan worker if it is running. We don't want it to
1388 * be still running after we are in RO mode, as after that, by the time
1389 * we unmount, it might have left a transaction open, so we would leak
1390 * the transaction and/or crash.
1391 */
1392 btrfs_qgroup_wait_for_completion(fs_info, false);
1393
1394 return btrfs_commit_super(fs_info);
1395 }
1396
btrfs_ctx_to_info(struct btrfs_fs_info * fs_info,struct btrfs_fs_context * ctx)1397 static void btrfs_ctx_to_info(struct btrfs_fs_info *fs_info, struct btrfs_fs_context *ctx)
1398 {
1399 fs_info->max_inline = ctx->max_inline;
1400 fs_info->commit_interval = ctx->commit_interval;
1401 fs_info->metadata_ratio = ctx->metadata_ratio;
1402 fs_info->thread_pool_size = ctx->thread_pool_size;
1403 fs_info->mount_opt = ctx->mount_opt;
1404 fs_info->compress_type = ctx->compress_type;
1405 fs_info->compress_level = ctx->compress_level;
1406 }
1407
btrfs_info_to_ctx(struct btrfs_fs_info * fs_info,struct btrfs_fs_context * ctx)1408 static void btrfs_info_to_ctx(struct btrfs_fs_info *fs_info, struct btrfs_fs_context *ctx)
1409 {
1410 ctx->max_inline = fs_info->max_inline;
1411 ctx->commit_interval = fs_info->commit_interval;
1412 ctx->metadata_ratio = fs_info->metadata_ratio;
1413 ctx->thread_pool_size = fs_info->thread_pool_size;
1414 ctx->mount_opt = fs_info->mount_opt;
1415 ctx->compress_type = fs_info->compress_type;
1416 ctx->compress_level = fs_info->compress_level;
1417 }
1418
1419 #define btrfs_info_if_set(fs_info, old_ctx, opt, fmt, args...) \
1420 do { \
1421 if ((!old_ctx || !btrfs_raw_test_opt(old_ctx->mount_opt, opt)) && \
1422 btrfs_raw_test_opt(fs_info->mount_opt, opt)) \
1423 btrfs_info(fs_info, fmt, ##args); \
1424 } while (0)
1425
1426 #define btrfs_info_if_unset(fs_info, old_ctx, opt, fmt, args...) \
1427 do { \
1428 if ((old_ctx && btrfs_raw_test_opt(old_ctx->mount_opt, opt)) && \
1429 !btrfs_raw_test_opt(fs_info->mount_opt, opt)) \
1430 btrfs_info(fs_info, fmt, ##args); \
1431 } while (0)
1432
btrfs_emit_options(struct btrfs_fs_info * info,struct btrfs_fs_context * old)1433 static void btrfs_emit_options(struct btrfs_fs_info *info,
1434 struct btrfs_fs_context *old)
1435 {
1436 btrfs_info_if_set(info, old, NODATASUM, "setting nodatasum");
1437 btrfs_info_if_set(info, old, DEGRADED, "allowing degraded mounts");
1438 btrfs_info_if_set(info, old, NODATASUM, "setting nodatasum");
1439 btrfs_info_if_set(info, old, SSD, "enabling ssd optimizations");
1440 btrfs_info_if_set(info, old, SSD_SPREAD, "using spread ssd allocation scheme");
1441 btrfs_info_if_set(info, old, NOBARRIER, "turning off barriers");
1442 btrfs_info_if_set(info, old, NOTREELOG, "disabling tree log");
1443 btrfs_info_if_set(info, old, NOLOGREPLAY, "disabling log replay at mount time");
1444 btrfs_info_if_set(info, old, FLUSHONCOMMIT, "turning on flush-on-commit");
1445 btrfs_info_if_set(info, old, DISCARD_SYNC, "turning on sync discard");
1446 btrfs_info_if_set(info, old, DISCARD_ASYNC, "turning on async discard");
1447 btrfs_info_if_set(info, old, FREE_SPACE_TREE, "enabling free space tree");
1448 btrfs_info_if_set(info, old, SPACE_CACHE, "enabling disk space caching");
1449 btrfs_info_if_set(info, old, CLEAR_CACHE, "force clearing of disk cache");
1450 btrfs_info_if_set(info, old, AUTO_DEFRAG, "enabling auto defrag");
1451 btrfs_info_if_set(info, old, FRAGMENT_DATA, "fragmenting data");
1452 btrfs_info_if_set(info, old, FRAGMENT_METADATA, "fragmenting metadata");
1453 btrfs_info_if_set(info, old, REF_VERIFY, "doing ref verification");
1454 btrfs_info_if_set(info, old, USEBACKUPROOT, "trying to use backup root at mount time");
1455 btrfs_info_if_set(info, old, IGNOREBADROOTS, "ignoring bad roots");
1456 btrfs_info_if_set(info, old, IGNOREDATACSUMS, "ignoring data csums");
1457 btrfs_info_if_set(info, old, IGNOREMETACSUMS, "ignoring meta csums");
1458 btrfs_info_if_set(info, old, IGNORESUPERFLAGS, "ignoring unknown super block flags");
1459
1460 btrfs_info_if_unset(info, old, NODATACOW, "setting datacow");
1461 btrfs_info_if_unset(info, old, SSD, "not using ssd optimizations");
1462 btrfs_info_if_unset(info, old, SSD_SPREAD, "not using spread ssd allocation scheme");
1463 btrfs_info_if_unset(info, old, NOBARRIER, "turning off barriers");
1464 btrfs_info_if_unset(info, old, NOTREELOG, "enabling tree log");
1465 btrfs_info_if_unset(info, old, SPACE_CACHE, "disabling disk space caching");
1466 btrfs_info_if_unset(info, old, FREE_SPACE_TREE, "disabling free space tree");
1467 btrfs_info_if_unset(info, old, AUTO_DEFRAG, "disabling auto defrag");
1468 btrfs_info_if_unset(info, old, COMPRESS, "use no compression");
1469
1470 /* Did the compression settings change? */
1471 if (btrfs_test_opt(info, COMPRESS) &&
1472 (!old ||
1473 old->compress_type != info->compress_type ||
1474 old->compress_level != info->compress_level ||
1475 (!btrfs_raw_test_opt(old->mount_opt, FORCE_COMPRESS) &&
1476 btrfs_raw_test_opt(info->mount_opt, FORCE_COMPRESS)))) {
1477 const char *compress_type = btrfs_compress_type2str(info->compress_type);
1478
1479 btrfs_info(info, "%s %s compression, level %d",
1480 btrfs_test_opt(info, FORCE_COMPRESS) ? "force" : "use",
1481 compress_type, info->compress_level);
1482 }
1483
1484 if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE)
1485 btrfs_info(info, "max_inline set to %llu", info->max_inline);
1486 }
1487
btrfs_reconfigure(struct fs_context * fc)1488 static int btrfs_reconfigure(struct fs_context *fc)
1489 {
1490 struct super_block *sb = fc->root->d_sb;
1491 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1492 struct btrfs_fs_context *ctx = fc->fs_private;
1493 struct btrfs_fs_context old_ctx;
1494 int ret = 0;
1495 bool mount_reconfigure = (fc->s_fs_info != NULL);
1496
1497 btrfs_info_to_ctx(fs_info, &old_ctx);
1498
1499 /*
1500 * This is our "bind mount" trick, we don't want to allow the user to do
1501 * anything other than mount a different ro/rw and a different subvol,
1502 * all of the mount options should be maintained.
1503 */
1504 if (mount_reconfigure)
1505 ctx->mount_opt = old_ctx.mount_opt;
1506
1507 sync_filesystem(sb);
1508 set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1509
1510 if (!btrfs_check_options(fs_info, &ctx->mount_opt, fc->sb_flags))
1511 return -EINVAL;
1512
1513 ret = btrfs_check_features(fs_info, !(fc->sb_flags & SB_RDONLY));
1514 if (ret < 0)
1515 return ret;
1516
1517 btrfs_ctx_to_info(fs_info, ctx);
1518 btrfs_remount_begin(fs_info, old_ctx.mount_opt, fc->sb_flags);
1519 btrfs_resize_thread_pool(fs_info, fs_info->thread_pool_size,
1520 old_ctx.thread_pool_size);
1521
1522 if ((bool)btrfs_test_opt(fs_info, FREE_SPACE_TREE) !=
1523 (bool)btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE) &&
1524 (!sb_rdonly(sb) || (fc->sb_flags & SB_RDONLY))) {
1525 btrfs_warn(fs_info,
1526 "remount supports changing free space tree only from RO to RW");
1527 /* Make sure free space cache options match the state on disk. */
1528 if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE)) {
1529 btrfs_set_opt(fs_info->mount_opt, FREE_SPACE_TREE);
1530 btrfs_clear_opt(fs_info->mount_opt, SPACE_CACHE);
1531 }
1532 if (btrfs_free_space_cache_v1_active(fs_info)) {
1533 btrfs_clear_opt(fs_info->mount_opt, FREE_SPACE_TREE);
1534 btrfs_set_opt(fs_info->mount_opt, SPACE_CACHE);
1535 }
1536 }
1537
1538 ret = 0;
1539 if (!sb_rdonly(sb) && (fc->sb_flags & SB_RDONLY))
1540 ret = btrfs_remount_ro(fs_info);
1541 else if (sb_rdonly(sb) && !(fc->sb_flags & SB_RDONLY))
1542 ret = btrfs_remount_rw(fs_info);
1543 if (ret)
1544 goto restore;
1545
1546 /*
1547 * If we set the mask during the parameter parsing VFS would reject the
1548 * remount. Here we can set the mask and the value will be updated
1549 * appropriately.
1550 */
1551 if ((fc->sb_flags & SB_POSIXACL) != (sb->s_flags & SB_POSIXACL))
1552 fc->sb_flags_mask |= SB_POSIXACL;
1553
1554 btrfs_emit_options(fs_info, &old_ctx);
1555 wake_up_process(fs_info->transaction_kthread);
1556 btrfs_remount_cleanup(fs_info, old_ctx.mount_opt);
1557 btrfs_clear_oneshot_options(fs_info);
1558 clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1559
1560 return 0;
1561 restore:
1562 btrfs_ctx_to_info(fs_info, &old_ctx);
1563 btrfs_remount_cleanup(fs_info, old_ctx.mount_opt);
1564 clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1565 return ret;
1566 }
1567
1568 /* Used to sort the devices by max_avail(descending sort) */
btrfs_cmp_device_free_bytes(const void * a,const void * b)1569 static int btrfs_cmp_device_free_bytes(const void *a, const void *b)
1570 {
1571 const struct btrfs_device_info *dev_info1 = a;
1572 const struct btrfs_device_info *dev_info2 = b;
1573
1574 if (dev_info1->max_avail > dev_info2->max_avail)
1575 return -1;
1576 else if (dev_info1->max_avail < dev_info2->max_avail)
1577 return 1;
1578 return 0;
1579 }
1580
1581 /*
1582 * sort the devices by max_avail, in which max free extent size of each device
1583 * is stored.(Descending Sort)
1584 */
btrfs_descending_sort_devices(struct btrfs_device_info * devices,size_t nr_devices)1585 static inline void btrfs_descending_sort_devices(
1586 struct btrfs_device_info *devices,
1587 size_t nr_devices)
1588 {
1589 sort(devices, nr_devices, sizeof(struct btrfs_device_info),
1590 btrfs_cmp_device_free_bytes, NULL);
1591 }
1592
1593 /*
1594 * The helper to calc the free space on the devices that can be used to store
1595 * file data.
1596 */
btrfs_calc_avail_data_space(struct btrfs_fs_info * fs_info,u64 * free_bytes)1597 static inline int btrfs_calc_avail_data_space(struct btrfs_fs_info *fs_info,
1598 u64 *free_bytes)
1599 {
1600 struct btrfs_device_info *devices_info;
1601 struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
1602 struct btrfs_device *device;
1603 u64 type;
1604 u64 avail_space;
1605 u64 min_stripe_size;
1606 int num_stripes = 1;
1607 int i = 0, nr_devices;
1608 const struct btrfs_raid_attr *rattr;
1609
1610 /*
1611 * We aren't under the device list lock, so this is racy-ish, but good
1612 * enough for our purposes.
1613 */
1614 nr_devices = fs_info->fs_devices->open_devices;
1615 if (!nr_devices) {
1616 smp_mb();
1617 nr_devices = fs_info->fs_devices->open_devices;
1618 ASSERT(nr_devices);
1619 if (!nr_devices) {
1620 *free_bytes = 0;
1621 return 0;
1622 }
1623 }
1624
1625 devices_info = kmalloc_array(nr_devices, sizeof(*devices_info),
1626 GFP_KERNEL);
1627 if (!devices_info)
1628 return -ENOMEM;
1629
1630 /* calc min stripe number for data space allocation */
1631 type = btrfs_data_alloc_profile(fs_info);
1632 rattr = &btrfs_raid_array[btrfs_bg_flags_to_raid_index(type)];
1633
1634 if (type & BTRFS_BLOCK_GROUP_RAID0)
1635 num_stripes = nr_devices;
1636 else if (type & BTRFS_BLOCK_GROUP_RAID1_MASK)
1637 num_stripes = rattr->ncopies;
1638 else if (type & BTRFS_BLOCK_GROUP_RAID10)
1639 num_stripes = 4;
1640
1641 /* Adjust for more than 1 stripe per device */
1642 min_stripe_size = rattr->dev_stripes * BTRFS_STRIPE_LEN;
1643
1644 rcu_read_lock();
1645 list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
1646 if (!test_bit(BTRFS_DEV_STATE_IN_FS_METADATA,
1647 &device->dev_state) ||
1648 !device->bdev ||
1649 test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state))
1650 continue;
1651
1652 if (i >= nr_devices)
1653 break;
1654
1655 avail_space = device->total_bytes - device->bytes_used;
1656
1657 /* align with stripe_len */
1658 avail_space = rounddown(avail_space, BTRFS_STRIPE_LEN);
1659
1660 /*
1661 * Ensure we have at least min_stripe_size on top of the
1662 * reserved space on the device.
1663 */
1664 if (avail_space <= BTRFS_DEVICE_RANGE_RESERVED + min_stripe_size)
1665 continue;
1666
1667 avail_space -= BTRFS_DEVICE_RANGE_RESERVED;
1668
1669 devices_info[i].dev = device;
1670 devices_info[i].max_avail = avail_space;
1671
1672 i++;
1673 }
1674 rcu_read_unlock();
1675
1676 nr_devices = i;
1677
1678 btrfs_descending_sort_devices(devices_info, nr_devices);
1679
1680 i = nr_devices - 1;
1681 avail_space = 0;
1682 while (nr_devices >= rattr->devs_min) {
1683 num_stripes = min(num_stripes, nr_devices);
1684
1685 if (devices_info[i].max_avail >= min_stripe_size) {
1686 int j;
1687 u64 alloc_size;
1688
1689 avail_space += devices_info[i].max_avail * num_stripes;
1690 alloc_size = devices_info[i].max_avail;
1691 for (j = i + 1 - num_stripes; j <= i; j++)
1692 devices_info[j].max_avail -= alloc_size;
1693 }
1694 i--;
1695 nr_devices--;
1696 }
1697
1698 kfree(devices_info);
1699 *free_bytes = avail_space;
1700 return 0;
1701 }
1702
1703 /*
1704 * Calculate numbers for 'df', pessimistic in case of mixed raid profiles.
1705 *
1706 * If there's a redundant raid level at DATA block groups, use the respective
1707 * multiplier to scale the sizes.
1708 *
1709 * Unused device space usage is based on simulating the chunk allocator
1710 * algorithm that respects the device sizes and order of allocations. This is
1711 * a close approximation of the actual use but there are other factors that may
1712 * change the result (like a new metadata chunk).
1713 *
1714 * If metadata is exhausted, f_bavail will be 0.
1715 */
btrfs_statfs(struct dentry * dentry,struct kstatfs * buf)1716 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
1717 {
1718 struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
1719 struct btrfs_super_block *disk_super = fs_info->super_copy;
1720 struct btrfs_space_info *found;
1721 u64 total_used = 0;
1722 u64 total_free_data = 0;
1723 u64 total_free_meta = 0;
1724 u32 bits = fs_info->sectorsize_bits;
1725 __be32 *fsid = (__be32 *)fs_info->fs_devices->fsid;
1726 unsigned factor = 1;
1727 struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
1728 int ret;
1729 u64 thresh = 0;
1730 int mixed = 0;
1731
1732 list_for_each_entry(found, &fs_info->space_info, list) {
1733 if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
1734 int i;
1735
1736 total_free_data += found->disk_total - found->disk_used;
1737 total_free_data -=
1738 btrfs_account_ro_block_groups_free_space(found);
1739
1740 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
1741 if (!list_empty(&found->block_groups[i]))
1742 factor = btrfs_bg_type_to_factor(
1743 btrfs_raid_array[i].bg_flag);
1744 }
1745 }
1746
1747 /*
1748 * Metadata in mixed block group profiles are accounted in data
1749 */
1750 if (!mixed && found->flags & BTRFS_BLOCK_GROUP_METADATA) {
1751 if (found->flags & BTRFS_BLOCK_GROUP_DATA)
1752 mixed = 1;
1753 else
1754 total_free_meta += found->disk_total -
1755 found->disk_used;
1756 }
1757
1758 total_used += found->disk_used;
1759 }
1760
1761 buf->f_blocks = div_u64(btrfs_super_total_bytes(disk_super), factor);
1762 buf->f_blocks >>= bits;
1763 buf->f_bfree = buf->f_blocks - (div_u64(total_used, factor) >> bits);
1764
1765 /* Account global block reserve as used, it's in logical size already */
1766 spin_lock(&block_rsv->lock);
1767 /* Mixed block groups accounting is not byte-accurate, avoid overflow */
1768 if (buf->f_bfree >= block_rsv->size >> bits)
1769 buf->f_bfree -= block_rsv->size >> bits;
1770 else
1771 buf->f_bfree = 0;
1772 spin_unlock(&block_rsv->lock);
1773
1774 buf->f_bavail = div_u64(total_free_data, factor);
1775 ret = btrfs_calc_avail_data_space(fs_info, &total_free_data);
1776 if (ret)
1777 return ret;
1778 buf->f_bavail += div_u64(total_free_data, factor);
1779 buf->f_bavail = buf->f_bavail >> bits;
1780
1781 /*
1782 * We calculate the remaining metadata space minus global reserve. If
1783 * this is (supposedly) smaller than zero, there's no space. But this
1784 * does not hold in practice, the exhausted state happens where's still
1785 * some positive delta. So we apply some guesswork and compare the
1786 * delta to a 4M threshold. (Practically observed delta was ~2M.)
1787 *
1788 * We probably cannot calculate the exact threshold value because this
1789 * depends on the internal reservations requested by various
1790 * operations, so some operations that consume a few metadata will
1791 * succeed even if the Avail is zero. But this is better than the other
1792 * way around.
1793 */
1794 thresh = SZ_4M;
1795
1796 /*
1797 * We only want to claim there's no available space if we can no longer
1798 * allocate chunks for our metadata profile and our global reserve will
1799 * not fit in the free metadata space. If we aren't ->full then we
1800 * still can allocate chunks and thus are fine using the currently
1801 * calculated f_bavail.
1802 */
1803 if (!mixed && block_rsv->space_info->full &&
1804 (total_free_meta < thresh || total_free_meta - thresh < block_rsv->size))
1805 buf->f_bavail = 0;
1806
1807 buf->f_type = BTRFS_SUPER_MAGIC;
1808 buf->f_bsize = fs_info->sectorsize;
1809 buf->f_namelen = BTRFS_NAME_LEN;
1810
1811 /* We treat it as constant endianness (it doesn't matter _which_)
1812 because we want the fsid to come out the same whether mounted
1813 on a big-endian or little-endian host */
1814 buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
1815 buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
1816 /* Mask in the root object ID too, to disambiguate subvols */
1817 buf->f_fsid.val[0] ^= btrfs_root_id(BTRFS_I(d_inode(dentry))->root) >> 32;
1818 buf->f_fsid.val[1] ^= btrfs_root_id(BTRFS_I(d_inode(dentry))->root);
1819
1820 return 0;
1821 }
1822
btrfs_fc_test_super(struct super_block * sb,struct fs_context * fc)1823 static int btrfs_fc_test_super(struct super_block *sb, struct fs_context *fc)
1824 {
1825 struct btrfs_fs_info *p = fc->s_fs_info;
1826 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1827
1828 return fs_info->fs_devices == p->fs_devices;
1829 }
1830
btrfs_get_tree_super(struct fs_context * fc)1831 static int btrfs_get_tree_super(struct fs_context *fc)
1832 {
1833 struct btrfs_fs_info *fs_info = fc->s_fs_info;
1834 struct btrfs_fs_context *ctx = fc->fs_private;
1835 struct btrfs_fs_devices *fs_devices = NULL;
1836 struct block_device *bdev;
1837 struct btrfs_device *device;
1838 struct super_block *sb;
1839 blk_mode_t mode = btrfs_open_mode(fc);
1840 int ret;
1841
1842 btrfs_ctx_to_info(fs_info, ctx);
1843 mutex_lock(&uuid_mutex);
1844
1845 /*
1846 * With 'true' passed to btrfs_scan_one_device() (mount time) we expect
1847 * either a valid device or an error.
1848 */
1849 device = btrfs_scan_one_device(fc->source, mode, true);
1850 ASSERT(device != NULL);
1851 if (IS_ERR(device)) {
1852 mutex_unlock(&uuid_mutex);
1853 return PTR_ERR(device);
1854 }
1855
1856 fs_devices = device->fs_devices;
1857 fs_info->fs_devices = fs_devices;
1858
1859 ret = btrfs_open_devices(fs_devices, mode, &btrfs_fs_type);
1860 mutex_unlock(&uuid_mutex);
1861 if (ret)
1862 return ret;
1863
1864 if (!(fc->sb_flags & SB_RDONLY) && fs_devices->rw_devices == 0) {
1865 ret = -EACCES;
1866 goto error;
1867 }
1868
1869 bdev = fs_devices->latest_dev->bdev;
1870
1871 /*
1872 * From now on the error handling is not straightforward.
1873 *
1874 * If successful, this will transfer the fs_info into the super block,
1875 * and fc->s_fs_info will be NULL. However if there's an existing
1876 * super, we'll still have fc->s_fs_info populated. If we error
1877 * completely out it'll be cleaned up when we drop the fs_context,
1878 * otherwise it's tied to the lifetime of the super_block.
1879 */
1880 sb = sget_fc(fc, btrfs_fc_test_super, set_anon_super_fc);
1881 if (IS_ERR(sb)) {
1882 ret = PTR_ERR(sb);
1883 goto error;
1884 }
1885
1886 set_device_specific_options(fs_info);
1887
1888 if (sb->s_root) {
1889 btrfs_close_devices(fs_devices);
1890 if ((fc->sb_flags ^ sb->s_flags) & SB_RDONLY)
1891 ret = -EBUSY;
1892 } else {
1893 snprintf(sb->s_id, sizeof(sb->s_id), "%pg", bdev);
1894 shrinker_debugfs_rename(sb->s_shrink, "sb-btrfs:%s", sb->s_id);
1895 btrfs_sb(sb)->bdev_holder = &btrfs_fs_type;
1896 ret = btrfs_fill_super(sb, fs_devices, NULL);
1897 }
1898
1899 if (ret) {
1900 deactivate_locked_super(sb);
1901 return ret;
1902 }
1903
1904 btrfs_clear_oneshot_options(fs_info);
1905
1906 fc->root = dget(sb->s_root);
1907 return 0;
1908
1909 error:
1910 btrfs_close_devices(fs_devices);
1911 return ret;
1912 }
1913
1914 /*
1915 * Ever since commit 0723a0473fb4 ("btrfs: allow mounting btrfs subvolumes
1916 * with different ro/rw options") the following works:
1917 *
1918 * (i) mount /dev/sda3 -o subvol=foo,ro /mnt/foo
1919 * (ii) mount /dev/sda3 -o subvol=bar,rw /mnt/bar
1920 *
1921 * which looks nice and innocent but is actually pretty intricate and deserves
1922 * a long comment.
1923 *
1924 * On another filesystem a subvolume mount is close to something like:
1925 *
1926 * (iii) # create rw superblock + initial mount
1927 * mount -t xfs /dev/sdb /opt/
1928 *
1929 * # create ro bind mount
1930 * mount --bind -o ro /opt/foo /mnt/foo
1931 *
1932 * # unmount initial mount
1933 * umount /opt
1934 *
1935 * Of course, there's some special subvolume sauce and there's the fact that the
1936 * sb->s_root dentry is really swapped after mount_subtree(). But conceptually
1937 * it's very close and will help us understand the issue.
1938 *
1939 * The old mount API didn't cleanly distinguish between a mount being made ro
1940 * and a superblock being made ro. The only way to change the ro state of
1941 * either object was by passing ms_rdonly. If a new mount was created via
1942 * mount(2) such as:
1943 *
1944 * mount("/dev/sdb", "/mnt", "xfs", ms_rdonly, null);
1945 *
1946 * the MS_RDONLY flag being specified had two effects:
1947 *
1948 * (1) MNT_READONLY was raised -> the resulting mount got
1949 * @mnt->mnt_flags |= MNT_READONLY raised.
1950 *
1951 * (2) MS_RDONLY was passed to the filesystem's mount method and the filesystems
1952 * made the superblock ro. Note, how SB_RDONLY has the same value as
1953 * ms_rdonly and is raised whenever MS_RDONLY is passed through mount(2).
1954 *
1955 * Creating a subtree mount via (iii) ends up leaving a rw superblock with a
1956 * subtree mounted ro.
1957 *
1958 * But consider the effect on the old mount API on btrfs subvolume mounting
1959 * which combines the distinct step in (iii) into a single step.
1960 *
1961 * By issuing (i) both the mount and the superblock are turned ro. Now when (ii)
1962 * is issued the superblock is ro and thus even if the mount created for (ii) is
1963 * rw it wouldn't help. Hence, btrfs needed to transition the superblock from ro
1964 * to rw for (ii) which it did using an internal remount call.
1965 *
1966 * IOW, subvolume mounting was inherently complicated due to the ambiguity of
1967 * MS_RDONLY in mount(2). Note, this ambiguity has mount(8) always translate
1968 * "ro" to MS_RDONLY. IOW, in both (i) and (ii) "ro" becomes MS_RDONLY when
1969 * passed by mount(8) to mount(2).
1970 *
1971 * Enter the new mount API. The new mount API disambiguates making a mount ro
1972 * and making a superblock ro.
1973 *
1974 * (3) To turn a mount ro the MOUNT_ATTR_ONLY flag can be used with either
1975 * fsmount() or mount_setattr() this is a pure VFS level change for a
1976 * specific mount or mount tree that is never seen by the filesystem itself.
1977 *
1978 * (4) To turn a superblock ro the "ro" flag must be used with
1979 * fsconfig(FSCONFIG_SET_FLAG, "ro"). This option is seen by the filesystem
1980 * in fc->sb_flags.
1981 *
1982 * This disambiguation has rather positive consequences. Mounting a subvolume
1983 * ro will not also turn the superblock ro. Only the mount for the subvolume
1984 * will become ro.
1985 *
1986 * So, if the superblock creation request comes from the new mount API the
1987 * caller must have explicitly done:
1988 *
1989 * fsconfig(FSCONFIG_SET_FLAG, "ro")
1990 * fsmount/mount_setattr(MOUNT_ATTR_RDONLY)
1991 *
1992 * IOW, at some point the caller must have explicitly turned the whole
1993 * superblock ro and we shouldn't just undo it like we did for the old mount
1994 * API. In any case, it lets us avoid the hack in the new mount API.
1995 *
1996 * Consequently, the remounting hack must only be used for requests originating
1997 * from the old mount API and should be marked for full deprecation so it can be
1998 * turned off in a couple of years.
1999 *
2000 * The new mount API has no reason to support this hack.
2001 */
btrfs_reconfigure_for_mount(struct fs_context * fc)2002 static struct vfsmount *btrfs_reconfigure_for_mount(struct fs_context *fc)
2003 {
2004 struct vfsmount *mnt;
2005 int ret;
2006 const bool ro2rw = !(fc->sb_flags & SB_RDONLY);
2007
2008 /*
2009 * We got an EBUSY because our SB_RDONLY flag didn't match the existing
2010 * super block, so invert our setting here and retry the mount so we
2011 * can get our vfsmount.
2012 */
2013 if (ro2rw)
2014 fc->sb_flags |= SB_RDONLY;
2015 else
2016 fc->sb_flags &= ~SB_RDONLY;
2017
2018 mnt = fc_mount(fc);
2019 if (IS_ERR(mnt))
2020 return mnt;
2021
2022 if (!fc->oldapi || !ro2rw)
2023 return mnt;
2024
2025 /* We need to convert to rw, call reconfigure. */
2026 fc->sb_flags &= ~SB_RDONLY;
2027 down_write(&mnt->mnt_sb->s_umount);
2028 ret = btrfs_reconfigure(fc);
2029 up_write(&mnt->mnt_sb->s_umount);
2030 if (ret) {
2031 mntput(mnt);
2032 return ERR_PTR(ret);
2033 }
2034 return mnt;
2035 }
2036
btrfs_get_tree_subvol(struct fs_context * fc)2037 static int btrfs_get_tree_subvol(struct fs_context *fc)
2038 {
2039 struct btrfs_fs_info *fs_info = NULL;
2040 struct btrfs_fs_context *ctx = fc->fs_private;
2041 struct fs_context *dup_fc;
2042 struct dentry *dentry;
2043 struct vfsmount *mnt;
2044
2045 /*
2046 * Setup a dummy root and fs_info for test/set super. This is because
2047 * we don't actually fill this stuff out until open_ctree, but we need
2048 * then open_ctree will properly initialize the file system specific
2049 * settings later. btrfs_init_fs_info initializes the static elements
2050 * of the fs_info (locks and such) to make cleanup easier if we find a
2051 * superblock with our given fs_devices later on at sget() time.
2052 */
2053 fs_info = kvzalloc(sizeof(struct btrfs_fs_info), GFP_KERNEL);
2054 if (!fs_info)
2055 return -ENOMEM;
2056
2057 fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
2058 fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
2059 if (!fs_info->super_copy || !fs_info->super_for_commit) {
2060 btrfs_free_fs_info(fs_info);
2061 return -ENOMEM;
2062 }
2063 btrfs_init_fs_info(fs_info);
2064
2065 dup_fc = vfs_dup_fs_context(fc);
2066 if (IS_ERR(dup_fc)) {
2067 btrfs_free_fs_info(fs_info);
2068 return PTR_ERR(dup_fc);
2069 }
2070
2071 /*
2072 * When we do the sget_fc this gets transferred to the sb, so we only
2073 * need to set it on the dup_fc as this is what creates the super block.
2074 */
2075 dup_fc->s_fs_info = fs_info;
2076
2077 /*
2078 * We'll do the security settings in our btrfs_get_tree_super() mount
2079 * loop, they were duplicated into dup_fc, we can drop the originals
2080 * here.
2081 */
2082 security_free_mnt_opts(&fc->security);
2083 fc->security = NULL;
2084
2085 mnt = fc_mount(dup_fc);
2086 if (PTR_ERR_OR_ZERO(mnt) == -EBUSY)
2087 mnt = btrfs_reconfigure_for_mount(dup_fc);
2088 put_fs_context(dup_fc);
2089 if (IS_ERR(mnt))
2090 return PTR_ERR(mnt);
2091
2092 /*
2093 * This free's ->subvol_name, because if it isn't set we have to
2094 * allocate a buffer to hold the subvol_name, so we just drop our
2095 * reference to it here.
2096 */
2097 dentry = mount_subvol(ctx->subvol_name, ctx->subvol_objectid, mnt);
2098 ctx->subvol_name = NULL;
2099 if (IS_ERR(dentry))
2100 return PTR_ERR(dentry);
2101
2102 fc->root = dentry;
2103 return 0;
2104 }
2105
btrfs_get_tree(struct fs_context * fc)2106 static int btrfs_get_tree(struct fs_context *fc)
2107 {
2108 /*
2109 * Since we use mount_subtree to mount the default/specified subvol, we
2110 * have to do mounts in two steps.
2111 *
2112 * First pass through we call btrfs_get_tree_subvol(), this is just a
2113 * wrapper around fc_mount() to call back into here again, and this time
2114 * we'll call btrfs_get_tree_super(). This will do the open_ctree() and
2115 * everything to open the devices and file system. Then we return back
2116 * with a fully constructed vfsmount in btrfs_get_tree_subvol(), and
2117 * from there we can do our mount_subvol() call, which will lookup
2118 * whichever subvol we're mounting and setup this fc with the
2119 * appropriate dentry for the subvol.
2120 */
2121 if (fc->s_fs_info)
2122 return btrfs_get_tree_super(fc);
2123 return btrfs_get_tree_subvol(fc);
2124 }
2125
btrfs_kill_super(struct super_block * sb)2126 static void btrfs_kill_super(struct super_block *sb)
2127 {
2128 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2129 kill_anon_super(sb);
2130 btrfs_free_fs_info(fs_info);
2131 }
2132
btrfs_free_fs_context(struct fs_context * fc)2133 static void btrfs_free_fs_context(struct fs_context *fc)
2134 {
2135 struct btrfs_fs_context *ctx = fc->fs_private;
2136 struct btrfs_fs_info *fs_info = fc->s_fs_info;
2137
2138 if (fs_info)
2139 btrfs_free_fs_info(fs_info);
2140
2141 if (ctx && refcount_dec_and_test(&ctx->refs)) {
2142 kfree(ctx->subvol_name);
2143 kfree(ctx);
2144 }
2145 }
2146
btrfs_dup_fs_context(struct fs_context * fc,struct fs_context * src_fc)2147 static int btrfs_dup_fs_context(struct fs_context *fc, struct fs_context *src_fc)
2148 {
2149 struct btrfs_fs_context *ctx = src_fc->fs_private;
2150
2151 /*
2152 * Give a ref to our ctx to this dup, as we want to keep it around for
2153 * our original fc so we can have the subvolume name or objectid.
2154 *
2155 * We unset ->source in the original fc because the dup needs it for
2156 * mounting, and then once we free the dup it'll free ->source, so we
2157 * need to make sure we're only pointing to it in one fc.
2158 */
2159 refcount_inc(&ctx->refs);
2160 fc->fs_private = ctx;
2161 fc->source = src_fc->source;
2162 src_fc->source = NULL;
2163 return 0;
2164 }
2165
2166 static const struct fs_context_operations btrfs_fs_context_ops = {
2167 .parse_param = btrfs_parse_param,
2168 .reconfigure = btrfs_reconfigure,
2169 .get_tree = btrfs_get_tree,
2170 .dup = btrfs_dup_fs_context,
2171 .free = btrfs_free_fs_context,
2172 };
2173
btrfs_init_fs_context(struct fs_context * fc)2174 static int btrfs_init_fs_context(struct fs_context *fc)
2175 {
2176 struct btrfs_fs_context *ctx;
2177
2178 ctx = kzalloc(sizeof(struct btrfs_fs_context), GFP_KERNEL);
2179 if (!ctx)
2180 return -ENOMEM;
2181
2182 refcount_set(&ctx->refs, 1);
2183 fc->fs_private = ctx;
2184 fc->ops = &btrfs_fs_context_ops;
2185
2186 if (fc->purpose == FS_CONTEXT_FOR_RECONFIGURE) {
2187 btrfs_info_to_ctx(btrfs_sb(fc->root->d_sb), ctx);
2188 } else {
2189 ctx->thread_pool_size =
2190 min_t(unsigned long, num_online_cpus() + 2, 8);
2191 ctx->max_inline = BTRFS_DEFAULT_MAX_INLINE;
2192 ctx->commit_interval = BTRFS_DEFAULT_COMMIT_INTERVAL;
2193 }
2194
2195 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
2196 fc->sb_flags |= SB_POSIXACL;
2197 #endif
2198 fc->sb_flags |= SB_I_VERSION;
2199
2200 return 0;
2201 }
2202
2203 static struct file_system_type btrfs_fs_type = {
2204 .owner = THIS_MODULE,
2205 .name = "btrfs",
2206 .init_fs_context = btrfs_init_fs_context,
2207 .parameters = btrfs_fs_parameters,
2208 .kill_sb = btrfs_kill_super,
2209 .fs_flags = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA | FS_ALLOW_IDMAP,
2210 };
2211
2212 MODULE_ALIAS_FS("btrfs");
2213
btrfs_control_open(struct inode * inode,struct file * file)2214 static int btrfs_control_open(struct inode *inode, struct file *file)
2215 {
2216 /*
2217 * The control file's private_data is used to hold the
2218 * transaction when it is started and is used to keep
2219 * track of whether a transaction is already in progress.
2220 */
2221 file->private_data = NULL;
2222 return 0;
2223 }
2224
2225 /*
2226 * Used by /dev/btrfs-control for devices ioctls.
2227 */
btrfs_control_ioctl(struct file * file,unsigned int cmd,unsigned long arg)2228 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
2229 unsigned long arg)
2230 {
2231 struct btrfs_ioctl_vol_args *vol;
2232 struct btrfs_device *device = NULL;
2233 dev_t devt = 0;
2234 int ret = -ENOTTY;
2235
2236 if (!capable(CAP_SYS_ADMIN))
2237 return -EPERM;
2238
2239 vol = memdup_user((void __user *)arg, sizeof(*vol));
2240 if (IS_ERR(vol))
2241 return PTR_ERR(vol);
2242 ret = btrfs_check_ioctl_vol_args_path(vol);
2243 if (ret < 0)
2244 goto out;
2245
2246 switch (cmd) {
2247 case BTRFS_IOC_SCAN_DEV:
2248 mutex_lock(&uuid_mutex);
2249 /*
2250 * Scanning outside of mount can return NULL which would turn
2251 * into 0 error code.
2252 */
2253 device = btrfs_scan_one_device(vol->name, BLK_OPEN_READ, false);
2254 ret = PTR_ERR_OR_ZERO(device);
2255 mutex_unlock(&uuid_mutex);
2256 break;
2257 case BTRFS_IOC_FORGET_DEV:
2258 if (vol->name[0] != 0) {
2259 ret = lookup_bdev(vol->name, &devt);
2260 if (ret)
2261 break;
2262 }
2263 ret = btrfs_forget_devices(devt);
2264 break;
2265 case BTRFS_IOC_DEVICES_READY:
2266 mutex_lock(&uuid_mutex);
2267 /*
2268 * Scanning outside of mount can return NULL which would turn
2269 * into 0 error code.
2270 */
2271 device = btrfs_scan_one_device(vol->name, BLK_OPEN_READ, false);
2272 if (IS_ERR_OR_NULL(device)) {
2273 mutex_unlock(&uuid_mutex);
2274 ret = PTR_ERR(device);
2275 break;
2276 }
2277 ret = !(device->fs_devices->num_devices ==
2278 device->fs_devices->total_devices);
2279 mutex_unlock(&uuid_mutex);
2280 break;
2281 case BTRFS_IOC_GET_SUPPORTED_FEATURES:
2282 ret = btrfs_ioctl_get_supported_features((void __user*)arg);
2283 break;
2284 }
2285
2286 out:
2287 kfree(vol);
2288 return ret;
2289 }
2290
btrfs_freeze(struct super_block * sb)2291 static int btrfs_freeze(struct super_block *sb)
2292 {
2293 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2294
2295 set_bit(BTRFS_FS_FROZEN, &fs_info->flags);
2296 /*
2297 * We don't need a barrier here, we'll wait for any transaction that
2298 * could be in progress on other threads (and do delayed iputs that
2299 * we want to avoid on a frozen filesystem), or do the commit
2300 * ourselves.
2301 */
2302 return btrfs_commit_current_transaction(fs_info->tree_root);
2303 }
2304
check_dev_super(struct btrfs_device * dev)2305 static int check_dev_super(struct btrfs_device *dev)
2306 {
2307 struct btrfs_fs_info *fs_info = dev->fs_info;
2308 struct btrfs_super_block *sb;
2309 u64 last_trans;
2310 u16 csum_type;
2311 int ret = 0;
2312
2313 /* This should be called with fs still frozen. */
2314 ASSERT(test_bit(BTRFS_FS_FROZEN, &fs_info->flags));
2315
2316 /* Missing dev, no need to check. */
2317 if (!dev->bdev)
2318 return 0;
2319
2320 /* Only need to check the primary super block. */
2321 sb = btrfs_read_dev_one_super(dev->bdev, 0, true);
2322 if (IS_ERR(sb))
2323 return PTR_ERR(sb);
2324
2325 /* Verify the checksum. */
2326 csum_type = btrfs_super_csum_type(sb);
2327 if (csum_type != btrfs_super_csum_type(fs_info->super_copy)) {
2328 btrfs_err(fs_info, "csum type changed, has %u expect %u",
2329 csum_type, btrfs_super_csum_type(fs_info->super_copy));
2330 ret = -EUCLEAN;
2331 goto out;
2332 }
2333
2334 if (btrfs_check_super_csum(fs_info, sb)) {
2335 btrfs_err(fs_info, "csum for on-disk super block no longer matches");
2336 ret = -EUCLEAN;
2337 goto out;
2338 }
2339
2340 /* Btrfs_validate_super() includes fsid check against super->fsid. */
2341 ret = btrfs_validate_super(fs_info, sb, 0);
2342 if (ret < 0)
2343 goto out;
2344
2345 last_trans = btrfs_get_last_trans_committed(fs_info);
2346 if (btrfs_super_generation(sb) != last_trans) {
2347 btrfs_err(fs_info, "transid mismatch, has %llu expect %llu",
2348 btrfs_super_generation(sb), last_trans);
2349 ret = -EUCLEAN;
2350 goto out;
2351 }
2352 out:
2353 btrfs_release_disk_super(sb);
2354 return ret;
2355 }
2356
btrfs_unfreeze(struct super_block * sb)2357 static int btrfs_unfreeze(struct super_block *sb)
2358 {
2359 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2360 struct btrfs_device *device;
2361 int ret = 0;
2362
2363 /*
2364 * Make sure the fs is not changed by accident (like hibernation then
2365 * modified by other OS).
2366 * If we found anything wrong, we mark the fs error immediately.
2367 *
2368 * And since the fs is frozen, no one can modify the fs yet, thus
2369 * we don't need to hold device_list_mutex.
2370 */
2371 list_for_each_entry(device, &fs_info->fs_devices->devices, dev_list) {
2372 ret = check_dev_super(device);
2373 if (ret < 0) {
2374 btrfs_handle_fs_error(fs_info, ret,
2375 "super block on devid %llu got modified unexpectedly",
2376 device->devid);
2377 break;
2378 }
2379 }
2380 clear_bit(BTRFS_FS_FROZEN, &fs_info->flags);
2381
2382 /*
2383 * We still return 0, to allow VFS layer to unfreeze the fs even the
2384 * above checks failed. Since the fs is either fine or read-only, we're
2385 * safe to continue, without causing further damage.
2386 */
2387 return 0;
2388 }
2389
btrfs_show_devname(struct seq_file * m,struct dentry * root)2390 static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
2391 {
2392 struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
2393
2394 /*
2395 * There should be always a valid pointer in latest_dev, it may be stale
2396 * for a short moment in case it's being deleted but still valid until
2397 * the end of RCU grace period.
2398 */
2399 rcu_read_lock();
2400 seq_escape(m, btrfs_dev_name(fs_info->fs_devices->latest_dev), " \t\n\\");
2401 rcu_read_unlock();
2402
2403 return 0;
2404 }
2405
btrfs_nr_cached_objects(struct super_block * sb,struct shrink_control * sc)2406 static long btrfs_nr_cached_objects(struct super_block *sb, struct shrink_control *sc)
2407 {
2408 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2409 const s64 nr = percpu_counter_sum_positive(&fs_info->evictable_extent_maps);
2410
2411 trace_btrfs_extent_map_shrinker_count(fs_info, nr);
2412
2413 /*
2414 * Only report the real number for DEBUG builds, as there are reports of
2415 * serious performance degradation caused by too frequent shrinks.
2416 */
2417 if (IS_ENABLED(CONFIG_BTRFS_DEBUG))
2418 return nr;
2419 return 0;
2420 }
2421
btrfs_free_cached_objects(struct super_block * sb,struct shrink_control * sc)2422 static long btrfs_free_cached_objects(struct super_block *sb, struct shrink_control *sc)
2423 {
2424 const long nr_to_scan = min_t(unsigned long, LONG_MAX, sc->nr_to_scan);
2425 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2426
2427 /*
2428 * We may be called from any task trying to allocate memory and we don't
2429 * want to slow it down with scanning and dropping extent maps. It would
2430 * also cause heavy lock contention if many tasks concurrently enter
2431 * here. Therefore only allow kswapd tasks to scan and drop extent maps.
2432 */
2433 if (!current_is_kswapd())
2434 return 0;
2435
2436 return btrfs_free_extent_maps(fs_info, nr_to_scan);
2437 }
2438
2439 static const struct super_operations btrfs_super_ops = {
2440 .drop_inode = btrfs_drop_inode,
2441 .evict_inode = btrfs_evict_inode,
2442 .put_super = btrfs_put_super,
2443 .sync_fs = btrfs_sync_fs,
2444 .show_options = btrfs_show_options,
2445 .show_devname = btrfs_show_devname,
2446 .alloc_inode = btrfs_alloc_inode,
2447 .destroy_inode = btrfs_destroy_inode,
2448 .free_inode = btrfs_free_inode,
2449 .statfs = btrfs_statfs,
2450 .freeze_fs = btrfs_freeze,
2451 .unfreeze_fs = btrfs_unfreeze,
2452 .nr_cached_objects = btrfs_nr_cached_objects,
2453 .free_cached_objects = btrfs_free_cached_objects,
2454 };
2455
2456 static const struct file_operations btrfs_ctl_fops = {
2457 .open = btrfs_control_open,
2458 .unlocked_ioctl = btrfs_control_ioctl,
2459 .compat_ioctl = compat_ptr_ioctl,
2460 .owner = THIS_MODULE,
2461 .llseek = noop_llseek,
2462 };
2463
2464 static struct miscdevice btrfs_misc = {
2465 .minor = BTRFS_MINOR,
2466 .name = "btrfs-control",
2467 .fops = &btrfs_ctl_fops
2468 };
2469
2470 MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
2471 MODULE_ALIAS("devname:btrfs-control");
2472
btrfs_interface_init(void)2473 static int __init btrfs_interface_init(void)
2474 {
2475 return misc_register(&btrfs_misc);
2476 }
2477
btrfs_interface_exit(void)2478 static __cold void btrfs_interface_exit(void)
2479 {
2480 misc_deregister(&btrfs_misc);
2481 }
2482
btrfs_print_mod_info(void)2483 static int __init btrfs_print_mod_info(void)
2484 {
2485 static const char options[] = ""
2486 #ifdef CONFIG_BTRFS_DEBUG
2487 ", debug=on"
2488 #endif
2489 #ifdef CONFIG_BTRFS_ASSERT
2490 ", assert=on"
2491 #endif
2492 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
2493 ", ref-verify=on"
2494 #endif
2495 #ifdef CONFIG_BLK_DEV_ZONED
2496 ", zoned=yes"
2497 #else
2498 ", zoned=no"
2499 #endif
2500 #ifdef CONFIG_FS_VERITY
2501 ", fsverity=yes"
2502 #else
2503 ", fsverity=no"
2504 #endif
2505 ;
2506 pr_info("Btrfs loaded%s\n", options);
2507 return 0;
2508 }
2509
register_btrfs(void)2510 static int register_btrfs(void)
2511 {
2512 return register_filesystem(&btrfs_fs_type);
2513 }
2514
unregister_btrfs(void)2515 static void unregister_btrfs(void)
2516 {
2517 unregister_filesystem(&btrfs_fs_type);
2518 }
2519
2520 /* Helper structure for long init/exit functions. */
2521 struct init_sequence {
2522 int (*init_func)(void);
2523 /* Can be NULL if the init_func doesn't need cleanup. */
2524 void (*exit_func)(void);
2525 };
2526
2527 static const struct init_sequence mod_init_seq[] = {
2528 {
2529 .init_func = btrfs_props_init,
2530 .exit_func = NULL,
2531 }, {
2532 .init_func = btrfs_init_sysfs,
2533 .exit_func = btrfs_exit_sysfs,
2534 }, {
2535 .init_func = btrfs_init_compress,
2536 .exit_func = btrfs_exit_compress,
2537 }, {
2538 .init_func = btrfs_init_cachep,
2539 .exit_func = btrfs_destroy_cachep,
2540 }, {
2541 .init_func = btrfs_init_dio,
2542 .exit_func = btrfs_destroy_dio,
2543 }, {
2544 .init_func = btrfs_transaction_init,
2545 .exit_func = btrfs_transaction_exit,
2546 }, {
2547 .init_func = btrfs_ctree_init,
2548 .exit_func = btrfs_ctree_exit,
2549 }, {
2550 .init_func = btrfs_free_space_init,
2551 .exit_func = btrfs_free_space_exit,
2552 }, {
2553 .init_func = extent_state_init_cachep,
2554 .exit_func = extent_state_free_cachep,
2555 }, {
2556 .init_func = extent_buffer_init_cachep,
2557 .exit_func = extent_buffer_free_cachep,
2558 }, {
2559 .init_func = btrfs_bioset_init,
2560 .exit_func = btrfs_bioset_exit,
2561 }, {
2562 .init_func = extent_map_init,
2563 .exit_func = extent_map_exit,
2564 }, {
2565 .init_func = ordered_data_init,
2566 .exit_func = ordered_data_exit,
2567 }, {
2568 .init_func = btrfs_delayed_inode_init,
2569 .exit_func = btrfs_delayed_inode_exit,
2570 }, {
2571 .init_func = btrfs_auto_defrag_init,
2572 .exit_func = btrfs_auto_defrag_exit,
2573 }, {
2574 .init_func = btrfs_delayed_ref_init,
2575 .exit_func = btrfs_delayed_ref_exit,
2576 }, {
2577 .init_func = btrfs_prelim_ref_init,
2578 .exit_func = btrfs_prelim_ref_exit,
2579 }, {
2580 .init_func = btrfs_interface_init,
2581 .exit_func = btrfs_interface_exit,
2582 }, {
2583 .init_func = btrfs_print_mod_info,
2584 .exit_func = NULL,
2585 }, {
2586 .init_func = btrfs_run_sanity_tests,
2587 .exit_func = NULL,
2588 }, {
2589 .init_func = register_btrfs,
2590 .exit_func = unregister_btrfs,
2591 }
2592 };
2593
2594 static bool mod_init_result[ARRAY_SIZE(mod_init_seq)];
2595
btrfs_exit_btrfs_fs(void)2596 static __always_inline void btrfs_exit_btrfs_fs(void)
2597 {
2598 int i;
2599
2600 for (i = ARRAY_SIZE(mod_init_seq) - 1; i >= 0; i--) {
2601 if (!mod_init_result[i])
2602 continue;
2603 if (mod_init_seq[i].exit_func)
2604 mod_init_seq[i].exit_func();
2605 mod_init_result[i] = false;
2606 }
2607 }
2608
exit_btrfs_fs(void)2609 static void __exit exit_btrfs_fs(void)
2610 {
2611 btrfs_exit_btrfs_fs();
2612 btrfs_cleanup_fs_uuids();
2613 }
2614
init_btrfs_fs(void)2615 static int __init init_btrfs_fs(void)
2616 {
2617 int ret;
2618 int i;
2619
2620 for (i = 0; i < ARRAY_SIZE(mod_init_seq); i++) {
2621 ASSERT(!mod_init_result[i]);
2622 ret = mod_init_seq[i].init_func();
2623 if (ret < 0) {
2624 btrfs_exit_btrfs_fs();
2625 return ret;
2626 }
2627 mod_init_result[i] = true;
2628 }
2629 return 0;
2630 }
2631
2632 late_initcall(init_btrfs_fs);
2633 module_exit(exit_btrfs_fs)
2634
2635 MODULE_DESCRIPTION("B-Tree File System (BTRFS)");
2636 MODULE_LICENSE("GPL");
2637 MODULE_SOFTDEP("pre: crc32c");
2638 MODULE_SOFTDEP("pre: xxhash64");
2639 MODULE_SOFTDEP("pre: sha256");
2640 MODULE_SOFTDEP("pre: blake2b-256");
2641