1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (C) 2007 Oracle. All rights reserved.
4 */
5
6 #include <linux/blkdev.h>
7 #include <linux/module.h>
8 #include <linux/fs.h>
9 #include <linux/pagemap.h>
10 #include <linux/highmem.h>
11 #include <linux/time.h>
12 #include <linux/init.h>
13 #include <linux/seq_file.h>
14 #include <linux/string.h>
15 #include <linux/backing-dev.h>
16 #include <linux/mount.h>
17 #include <linux/writeback.h>
18 #include <linux/statfs.h>
19 #include <linux/compat.h>
20 #include <linux/parser.h>
21 #include <linux/ctype.h>
22 #include <linux/namei.h>
23 #include <linux/miscdevice.h>
24 #include <linux/magic.h>
25 #include <linux/slab.h>
26 #include <linux/ratelimit.h>
27 #include <linux/crc32c.h>
28 #include <linux/btrfs.h>
29 #include <linux/security.h>
30 #include <linux/fs_parser.h>
31 #include "messages.h"
32 #include "delayed-inode.h"
33 #include "ctree.h"
34 #include "disk-io.h"
35 #include "transaction.h"
36 #include "btrfs_inode.h"
37 #include "direct-io.h"
38 #include "props.h"
39 #include "xattr.h"
40 #include "bio.h"
41 #include "export.h"
42 #include "compression.h"
43 #include "dev-replace.h"
44 #include "free-space-cache.h"
45 #include "backref.h"
46 #include "space-info.h"
47 #include "sysfs.h"
48 #include "zoned.h"
49 #include "tests/btrfs-tests.h"
50 #include "block-group.h"
51 #include "discard.h"
52 #include "qgroup.h"
53 #include "raid56.h"
54 #include "fs.h"
55 #include "accessors.h"
56 #include "defrag.h"
57 #include "dir-item.h"
58 #include "ioctl.h"
59 #include "scrub.h"
60 #include "verity.h"
61 #include "super.h"
62 #include "extent-tree.h"
63 #define CREATE_TRACE_POINTS
64 #include <trace/events/btrfs.h>
65
66 static const struct super_operations btrfs_super_ops;
67 static struct file_system_type btrfs_fs_type;
68
btrfs_put_super(struct super_block * sb)69 static void btrfs_put_super(struct super_block *sb)
70 {
71 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
72
73 btrfs_info(fs_info, "last unmount of filesystem %pU", fs_info->fs_devices->fsid);
74 close_ctree(fs_info);
75 }
76
77 /* Store the mount options related information. */
78 struct btrfs_fs_context {
79 char *subvol_name;
80 u64 subvol_objectid;
81 u64 max_inline;
82 u32 commit_interval;
83 u32 metadata_ratio;
84 u32 thread_pool_size;
85 unsigned long long mount_opt;
86 unsigned long compress_type:4;
87 int compress_level;
88 refcount_t refs;
89 };
90
91 static void btrfs_emit_options(struct btrfs_fs_info *info,
92 struct btrfs_fs_context *old);
93
94 enum {
95 Opt_acl,
96 Opt_clear_cache,
97 Opt_commit_interval,
98 Opt_compress,
99 Opt_compress_force,
100 Opt_compress_force_type,
101 Opt_compress_type,
102 Opt_degraded,
103 Opt_device,
104 Opt_fatal_errors,
105 Opt_flushoncommit,
106 Opt_max_inline,
107 Opt_barrier,
108 Opt_datacow,
109 Opt_datasum,
110 Opt_defrag,
111 Opt_discard,
112 Opt_discard_mode,
113 Opt_ratio,
114 Opt_rescan_uuid_tree,
115 Opt_skip_balance,
116 Opt_space_cache,
117 Opt_space_cache_version,
118 Opt_ssd,
119 Opt_ssd_spread,
120 Opt_subvol,
121 Opt_subvol_empty,
122 Opt_subvolid,
123 Opt_thread_pool,
124 Opt_treelog,
125 Opt_user_subvol_rm_allowed,
126 Opt_norecovery,
127
128 /* Rescue options */
129 Opt_rescue,
130 Opt_usebackuproot,
131
132 /* Debugging options */
133 Opt_enospc_debug,
134 #ifdef CONFIG_BTRFS_DEBUG
135 Opt_fragment, Opt_fragment_data, Opt_fragment_metadata, Opt_fragment_all,
136 #endif
137 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
138 Opt_ref_verify,
139 #endif
140 Opt_err,
141 };
142
143 enum {
144 Opt_fatal_errors_panic,
145 Opt_fatal_errors_bug,
146 };
147
148 static const struct constant_table btrfs_parameter_fatal_errors[] = {
149 { "panic", Opt_fatal_errors_panic },
150 { "bug", Opt_fatal_errors_bug },
151 {}
152 };
153
154 enum {
155 Opt_discard_sync,
156 Opt_discard_async,
157 };
158
159 static const struct constant_table btrfs_parameter_discard[] = {
160 { "sync", Opt_discard_sync },
161 { "async", Opt_discard_async },
162 {}
163 };
164
165 enum {
166 Opt_space_cache_v1,
167 Opt_space_cache_v2,
168 };
169
170 static const struct constant_table btrfs_parameter_space_cache[] = {
171 { "v1", Opt_space_cache_v1 },
172 { "v2", Opt_space_cache_v2 },
173 {}
174 };
175
176 enum {
177 Opt_rescue_usebackuproot,
178 Opt_rescue_nologreplay,
179 Opt_rescue_ignorebadroots,
180 Opt_rescue_ignoredatacsums,
181 Opt_rescue_ignoremetacsums,
182 Opt_rescue_ignoresuperflags,
183 Opt_rescue_parameter_all,
184 };
185
186 static const struct constant_table btrfs_parameter_rescue[] = {
187 { "usebackuproot", Opt_rescue_usebackuproot },
188 { "nologreplay", Opt_rescue_nologreplay },
189 { "ignorebadroots", Opt_rescue_ignorebadroots },
190 { "ibadroots", Opt_rescue_ignorebadroots },
191 { "ignoredatacsums", Opt_rescue_ignoredatacsums },
192 { "ignoremetacsums", Opt_rescue_ignoremetacsums},
193 { "ignoresuperflags", Opt_rescue_ignoresuperflags},
194 { "idatacsums", Opt_rescue_ignoredatacsums },
195 { "imetacsums", Opt_rescue_ignoremetacsums},
196 { "isuperflags", Opt_rescue_ignoresuperflags},
197 { "all", Opt_rescue_parameter_all },
198 {}
199 };
200
201 #ifdef CONFIG_BTRFS_DEBUG
202 enum {
203 Opt_fragment_parameter_data,
204 Opt_fragment_parameter_metadata,
205 Opt_fragment_parameter_all,
206 };
207
208 static const struct constant_table btrfs_parameter_fragment[] = {
209 { "data", Opt_fragment_parameter_data },
210 { "metadata", Opt_fragment_parameter_metadata },
211 { "all", Opt_fragment_parameter_all },
212 {}
213 };
214 #endif
215
216 static const struct fs_parameter_spec btrfs_fs_parameters[] = {
217 fsparam_flag_no("acl", Opt_acl),
218 fsparam_flag_no("autodefrag", Opt_defrag),
219 fsparam_flag_no("barrier", Opt_barrier),
220 fsparam_flag("clear_cache", Opt_clear_cache),
221 fsparam_u32("commit", Opt_commit_interval),
222 fsparam_flag("compress", Opt_compress),
223 fsparam_string("compress", Opt_compress_type),
224 fsparam_flag("compress-force", Opt_compress_force),
225 fsparam_string("compress-force", Opt_compress_force_type),
226 fsparam_flag_no("datacow", Opt_datacow),
227 fsparam_flag_no("datasum", Opt_datasum),
228 fsparam_flag("degraded", Opt_degraded),
229 fsparam_string("device", Opt_device),
230 fsparam_flag_no("discard", Opt_discard),
231 fsparam_enum("discard", Opt_discard_mode, btrfs_parameter_discard),
232 fsparam_enum("fatal_errors", Opt_fatal_errors, btrfs_parameter_fatal_errors),
233 fsparam_flag_no("flushoncommit", Opt_flushoncommit),
234 fsparam_string("max_inline", Opt_max_inline),
235 fsparam_u32("metadata_ratio", Opt_ratio),
236 fsparam_flag("rescan_uuid_tree", Opt_rescan_uuid_tree),
237 fsparam_flag("skip_balance", Opt_skip_balance),
238 fsparam_flag_no("space_cache", Opt_space_cache),
239 fsparam_enum("space_cache", Opt_space_cache_version, btrfs_parameter_space_cache),
240 fsparam_flag_no("ssd", Opt_ssd),
241 fsparam_flag_no("ssd_spread", Opt_ssd_spread),
242 fsparam_string("subvol", Opt_subvol),
243 fsparam_flag("subvol=", Opt_subvol_empty),
244 fsparam_u64("subvolid", Opt_subvolid),
245 fsparam_u32("thread_pool", Opt_thread_pool),
246 fsparam_flag_no("treelog", Opt_treelog),
247 fsparam_flag("user_subvol_rm_allowed", Opt_user_subvol_rm_allowed),
248
249 /* Rescue options. */
250 fsparam_enum("rescue", Opt_rescue, btrfs_parameter_rescue),
251 /* Deprecated, with alias rescue=usebackuproot */
252 __fsparam(NULL, "usebackuproot", Opt_usebackuproot, fs_param_deprecated, NULL),
253 /* For compatibility only, alias for "rescue=nologreplay". */
254 fsparam_flag("norecovery", Opt_norecovery),
255
256 /* Debugging options. */
257 fsparam_flag_no("enospc_debug", Opt_enospc_debug),
258 #ifdef CONFIG_BTRFS_DEBUG
259 fsparam_enum("fragment", Opt_fragment, btrfs_parameter_fragment),
260 #endif
261 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
262 fsparam_flag("ref_verify", Opt_ref_verify),
263 #endif
264 {}
265 };
266
btrfs_match_compress_type(const char * string,const char * type,bool may_have_level)267 static bool btrfs_match_compress_type(const char *string, const char *type, bool may_have_level)
268 {
269 const int len = strlen(type);
270
271 return (strncmp(string, type, len) == 0) &&
272 ((may_have_level && string[len] == ':') || string[len] == '\0');
273 }
274
btrfs_parse_compress(struct btrfs_fs_context * ctx,const struct fs_parameter * param,int opt)275 static int btrfs_parse_compress(struct btrfs_fs_context *ctx,
276 const struct fs_parameter *param, int opt)
277 {
278 const char *string = param->string;
279 int ret;
280
281 /*
282 * Provide the same semantics as older kernels that don't use fs
283 * context, specifying the "compress" option clears "force-compress"
284 * without the need to pass "compress-force=[no|none]" before
285 * specifying "compress".
286 */
287 if (opt != Opt_compress_force && opt != Opt_compress_force_type)
288 btrfs_clear_opt(ctx->mount_opt, FORCE_COMPRESS);
289
290 if (opt == Opt_compress || opt == Opt_compress_force) {
291 ctx->compress_type = BTRFS_COMPRESS_ZLIB;
292 ctx->compress_level = BTRFS_ZLIB_DEFAULT_LEVEL;
293 btrfs_set_opt(ctx->mount_opt, COMPRESS);
294 btrfs_clear_opt(ctx->mount_opt, NODATACOW);
295 btrfs_clear_opt(ctx->mount_opt, NODATASUM);
296 } else if (btrfs_match_compress_type(string, "zlib", true)) {
297 ctx->compress_type = BTRFS_COMPRESS_ZLIB;
298 ret = btrfs_compress_str2level(BTRFS_COMPRESS_ZLIB, string + 4,
299 &ctx->compress_level);
300 if (ret < 0)
301 goto error;
302 btrfs_set_opt(ctx->mount_opt, COMPRESS);
303 btrfs_clear_opt(ctx->mount_opt, NODATACOW);
304 btrfs_clear_opt(ctx->mount_opt, NODATASUM);
305 } else if (btrfs_match_compress_type(string, "lzo", true)) {
306 ctx->compress_type = BTRFS_COMPRESS_LZO;
307 ret = btrfs_compress_str2level(BTRFS_COMPRESS_LZO, string + 3,
308 &ctx->compress_level);
309 if (ret < 0)
310 goto error;
311 if (string[3] == ':' && string[4])
312 btrfs_warn(NULL, "Compression level ignored for LZO");
313 btrfs_set_opt(ctx->mount_opt, COMPRESS);
314 btrfs_clear_opt(ctx->mount_opt, NODATACOW);
315 btrfs_clear_opt(ctx->mount_opt, NODATASUM);
316 } else if (btrfs_match_compress_type(string, "zstd", true)) {
317 ctx->compress_type = BTRFS_COMPRESS_ZSTD;
318 ret = btrfs_compress_str2level(BTRFS_COMPRESS_ZSTD, string + 4,
319 &ctx->compress_level);
320 if (ret < 0)
321 goto error;
322 btrfs_set_opt(ctx->mount_opt, COMPRESS);
323 btrfs_clear_opt(ctx->mount_opt, NODATACOW);
324 btrfs_clear_opt(ctx->mount_opt, NODATASUM);
325 } else if (btrfs_match_compress_type(string, "no", false) ||
326 btrfs_match_compress_type(string, "none", false)) {
327 ctx->compress_level = 0;
328 ctx->compress_type = 0;
329 btrfs_clear_opt(ctx->mount_opt, COMPRESS);
330 btrfs_clear_opt(ctx->mount_opt, FORCE_COMPRESS);
331 } else {
332 ret = -EINVAL;
333 goto error;
334 }
335 return 0;
336 error:
337 btrfs_err(NULL, "failed to parse compression option '%s'", string);
338 return ret;
339
340 }
341
btrfs_parse_param(struct fs_context * fc,struct fs_parameter * param)342 static int btrfs_parse_param(struct fs_context *fc, struct fs_parameter *param)
343 {
344 struct btrfs_fs_context *ctx = fc->fs_private;
345 struct fs_parse_result result;
346 int opt;
347
348 opt = fs_parse(fc, btrfs_fs_parameters, param, &result);
349 if (opt < 0)
350 return opt;
351
352 switch (opt) {
353 case Opt_degraded:
354 btrfs_set_opt(ctx->mount_opt, DEGRADED);
355 break;
356 case Opt_subvol_empty:
357 /*
358 * This exists because we used to allow it on accident, so we're
359 * keeping it to maintain ABI. See 37becec95ac3 ("Btrfs: allow
360 * empty subvol= again").
361 */
362 break;
363 case Opt_subvol:
364 kfree(ctx->subvol_name);
365 ctx->subvol_name = kstrdup(param->string, GFP_KERNEL);
366 if (!ctx->subvol_name)
367 return -ENOMEM;
368 break;
369 case Opt_subvolid:
370 ctx->subvol_objectid = result.uint_64;
371
372 /* subvolid=0 means give me the original fs_tree. */
373 if (!ctx->subvol_objectid)
374 ctx->subvol_objectid = BTRFS_FS_TREE_OBJECTID;
375 break;
376 case Opt_device: {
377 struct btrfs_device *device;
378
379 mutex_lock(&uuid_mutex);
380 device = btrfs_scan_one_device(param->string, false);
381 mutex_unlock(&uuid_mutex);
382 if (IS_ERR(device))
383 return PTR_ERR(device);
384 break;
385 }
386 case Opt_datasum:
387 if (result.negated) {
388 btrfs_set_opt(ctx->mount_opt, NODATASUM);
389 } else {
390 btrfs_clear_opt(ctx->mount_opt, NODATACOW);
391 btrfs_clear_opt(ctx->mount_opt, NODATASUM);
392 }
393 break;
394 case Opt_datacow:
395 if (result.negated) {
396 btrfs_clear_opt(ctx->mount_opt, COMPRESS);
397 btrfs_clear_opt(ctx->mount_opt, FORCE_COMPRESS);
398 btrfs_set_opt(ctx->mount_opt, NODATACOW);
399 btrfs_set_opt(ctx->mount_opt, NODATASUM);
400 } else {
401 btrfs_clear_opt(ctx->mount_opt, NODATACOW);
402 }
403 break;
404 case Opt_compress_force:
405 case Opt_compress_force_type:
406 btrfs_set_opt(ctx->mount_opt, FORCE_COMPRESS);
407 fallthrough;
408 case Opt_compress:
409 case Opt_compress_type:
410 if (btrfs_parse_compress(ctx, param, opt))
411 return -EINVAL;
412 break;
413 case Opt_ssd:
414 if (result.negated) {
415 btrfs_set_opt(ctx->mount_opt, NOSSD);
416 btrfs_clear_opt(ctx->mount_opt, SSD);
417 btrfs_clear_opt(ctx->mount_opt, SSD_SPREAD);
418 } else {
419 btrfs_set_opt(ctx->mount_opt, SSD);
420 btrfs_clear_opt(ctx->mount_opt, NOSSD);
421 }
422 break;
423 case Opt_ssd_spread:
424 if (result.negated) {
425 btrfs_clear_opt(ctx->mount_opt, SSD_SPREAD);
426 } else {
427 btrfs_set_opt(ctx->mount_opt, SSD);
428 btrfs_set_opt(ctx->mount_opt, SSD_SPREAD);
429 btrfs_clear_opt(ctx->mount_opt, NOSSD);
430 }
431 break;
432 case Opt_barrier:
433 if (result.negated)
434 btrfs_set_opt(ctx->mount_opt, NOBARRIER);
435 else
436 btrfs_clear_opt(ctx->mount_opt, NOBARRIER);
437 break;
438 case Opt_thread_pool:
439 if (result.uint_32 == 0) {
440 btrfs_err(NULL, "invalid value 0 for thread_pool");
441 return -EINVAL;
442 }
443 ctx->thread_pool_size = result.uint_32;
444 break;
445 case Opt_max_inline:
446 ctx->max_inline = memparse(param->string, NULL);
447 break;
448 case Opt_acl:
449 if (result.negated) {
450 fc->sb_flags &= ~SB_POSIXACL;
451 } else {
452 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
453 fc->sb_flags |= SB_POSIXACL;
454 #else
455 btrfs_err(NULL, "support for ACL not compiled in");
456 return -EINVAL;
457 #endif
458 }
459 /*
460 * VFS limits the ability to toggle ACL on and off via remount,
461 * despite every file system allowing this. This seems to be
462 * an oversight since we all do, but it'll fail if we're
463 * remounting. So don't set the mask here, we'll check it in
464 * btrfs_reconfigure and do the toggling ourselves.
465 */
466 if (fc->purpose != FS_CONTEXT_FOR_RECONFIGURE)
467 fc->sb_flags_mask |= SB_POSIXACL;
468 break;
469 case Opt_treelog:
470 if (result.negated)
471 btrfs_set_opt(ctx->mount_opt, NOTREELOG);
472 else
473 btrfs_clear_opt(ctx->mount_opt, NOTREELOG);
474 break;
475 case Opt_norecovery:
476 btrfs_info(NULL,
477 "'norecovery' is for compatibility only, recommended to use 'rescue=nologreplay'");
478 btrfs_set_opt(ctx->mount_opt, NOLOGREPLAY);
479 break;
480 case Opt_flushoncommit:
481 if (result.negated)
482 btrfs_clear_opt(ctx->mount_opt, FLUSHONCOMMIT);
483 else
484 btrfs_set_opt(ctx->mount_opt, FLUSHONCOMMIT);
485 break;
486 case Opt_ratio:
487 ctx->metadata_ratio = result.uint_32;
488 break;
489 case Opt_discard:
490 if (result.negated) {
491 btrfs_clear_opt(ctx->mount_opt, DISCARD_SYNC);
492 btrfs_clear_opt(ctx->mount_opt, DISCARD_ASYNC);
493 btrfs_set_opt(ctx->mount_opt, NODISCARD);
494 } else {
495 btrfs_set_opt(ctx->mount_opt, DISCARD_SYNC);
496 btrfs_clear_opt(ctx->mount_opt, DISCARD_ASYNC);
497 }
498 break;
499 case Opt_discard_mode:
500 switch (result.uint_32) {
501 case Opt_discard_sync:
502 btrfs_clear_opt(ctx->mount_opt, DISCARD_ASYNC);
503 btrfs_set_opt(ctx->mount_opt, DISCARD_SYNC);
504 break;
505 case Opt_discard_async:
506 btrfs_clear_opt(ctx->mount_opt, DISCARD_SYNC);
507 btrfs_set_opt(ctx->mount_opt, DISCARD_ASYNC);
508 break;
509 default:
510 btrfs_err(NULL, "unrecognized discard mode value %s",
511 param->key);
512 return -EINVAL;
513 }
514 btrfs_clear_opt(ctx->mount_opt, NODISCARD);
515 break;
516 case Opt_space_cache:
517 if (result.negated) {
518 btrfs_set_opt(ctx->mount_opt, NOSPACECACHE);
519 btrfs_clear_opt(ctx->mount_opt, SPACE_CACHE);
520 btrfs_clear_opt(ctx->mount_opt, FREE_SPACE_TREE);
521 } else {
522 btrfs_clear_opt(ctx->mount_opt, FREE_SPACE_TREE);
523 btrfs_set_opt(ctx->mount_opt, SPACE_CACHE);
524 }
525 break;
526 case Opt_space_cache_version:
527 switch (result.uint_32) {
528 case Opt_space_cache_v1:
529 btrfs_set_opt(ctx->mount_opt, SPACE_CACHE);
530 btrfs_clear_opt(ctx->mount_opt, FREE_SPACE_TREE);
531 break;
532 case Opt_space_cache_v2:
533 btrfs_clear_opt(ctx->mount_opt, SPACE_CACHE);
534 btrfs_set_opt(ctx->mount_opt, FREE_SPACE_TREE);
535 break;
536 default:
537 btrfs_err(NULL, "unrecognized space_cache value %s",
538 param->key);
539 return -EINVAL;
540 }
541 break;
542 case Opt_rescan_uuid_tree:
543 btrfs_set_opt(ctx->mount_opt, RESCAN_UUID_TREE);
544 break;
545 case Opt_clear_cache:
546 btrfs_set_opt(ctx->mount_opt, CLEAR_CACHE);
547 break;
548 case Opt_user_subvol_rm_allowed:
549 btrfs_set_opt(ctx->mount_opt, USER_SUBVOL_RM_ALLOWED);
550 break;
551 case Opt_enospc_debug:
552 if (result.negated)
553 btrfs_clear_opt(ctx->mount_opt, ENOSPC_DEBUG);
554 else
555 btrfs_set_opt(ctx->mount_opt, ENOSPC_DEBUG);
556 break;
557 case Opt_defrag:
558 if (result.negated)
559 btrfs_clear_opt(ctx->mount_opt, AUTO_DEFRAG);
560 else
561 btrfs_set_opt(ctx->mount_opt, AUTO_DEFRAG);
562 break;
563 case Opt_usebackuproot:
564 btrfs_warn(NULL,
565 "'usebackuproot' is deprecated, use 'rescue=usebackuproot' instead");
566 btrfs_set_opt(ctx->mount_opt, USEBACKUPROOT);
567
568 /* If we're loading the backup roots we can't trust the space cache. */
569 btrfs_set_opt(ctx->mount_opt, CLEAR_CACHE);
570 break;
571 case Opt_skip_balance:
572 btrfs_set_opt(ctx->mount_opt, SKIP_BALANCE);
573 break;
574 case Opt_fatal_errors:
575 switch (result.uint_32) {
576 case Opt_fatal_errors_panic:
577 btrfs_set_opt(ctx->mount_opt, PANIC_ON_FATAL_ERROR);
578 break;
579 case Opt_fatal_errors_bug:
580 btrfs_clear_opt(ctx->mount_opt, PANIC_ON_FATAL_ERROR);
581 break;
582 default:
583 btrfs_err(NULL, "unrecognized fatal_errors value %s",
584 param->key);
585 return -EINVAL;
586 }
587 break;
588 case Opt_commit_interval:
589 ctx->commit_interval = result.uint_32;
590 if (ctx->commit_interval > BTRFS_WARNING_COMMIT_INTERVAL) {
591 btrfs_warn(NULL, "excessive commit interval %u, use with care",
592 ctx->commit_interval);
593 }
594 if (ctx->commit_interval == 0)
595 ctx->commit_interval = BTRFS_DEFAULT_COMMIT_INTERVAL;
596 break;
597 case Opt_rescue:
598 switch (result.uint_32) {
599 case Opt_rescue_usebackuproot:
600 btrfs_set_opt(ctx->mount_opt, USEBACKUPROOT);
601 break;
602 case Opt_rescue_nologreplay:
603 btrfs_set_opt(ctx->mount_opt, NOLOGREPLAY);
604 break;
605 case Opt_rescue_ignorebadroots:
606 btrfs_set_opt(ctx->mount_opt, IGNOREBADROOTS);
607 break;
608 case Opt_rescue_ignoredatacsums:
609 btrfs_set_opt(ctx->mount_opt, IGNOREDATACSUMS);
610 break;
611 case Opt_rescue_ignoremetacsums:
612 btrfs_set_opt(ctx->mount_opt, IGNOREMETACSUMS);
613 break;
614 case Opt_rescue_ignoresuperflags:
615 btrfs_set_opt(ctx->mount_opt, IGNORESUPERFLAGS);
616 break;
617 case Opt_rescue_parameter_all:
618 btrfs_set_opt(ctx->mount_opt, IGNOREDATACSUMS);
619 btrfs_set_opt(ctx->mount_opt, IGNOREMETACSUMS);
620 btrfs_set_opt(ctx->mount_opt, IGNORESUPERFLAGS);
621 btrfs_set_opt(ctx->mount_opt, IGNOREBADROOTS);
622 btrfs_set_opt(ctx->mount_opt, NOLOGREPLAY);
623 break;
624 default:
625 btrfs_info(NULL, "unrecognized rescue option '%s'",
626 param->key);
627 return -EINVAL;
628 }
629 break;
630 #ifdef CONFIG_BTRFS_DEBUG
631 case Opt_fragment:
632 switch (result.uint_32) {
633 case Opt_fragment_parameter_all:
634 btrfs_set_opt(ctx->mount_opt, FRAGMENT_DATA);
635 btrfs_set_opt(ctx->mount_opt, FRAGMENT_METADATA);
636 break;
637 case Opt_fragment_parameter_metadata:
638 btrfs_set_opt(ctx->mount_opt, FRAGMENT_METADATA);
639 break;
640 case Opt_fragment_parameter_data:
641 btrfs_set_opt(ctx->mount_opt, FRAGMENT_DATA);
642 break;
643 default:
644 btrfs_info(NULL, "unrecognized fragment option '%s'",
645 param->key);
646 return -EINVAL;
647 }
648 break;
649 #endif
650 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
651 case Opt_ref_verify:
652 btrfs_set_opt(ctx->mount_opt, REF_VERIFY);
653 break;
654 #endif
655 default:
656 btrfs_err(NULL, "unrecognized mount option '%s'", param->key);
657 return -EINVAL;
658 }
659
660 return 0;
661 }
662
663 /*
664 * Some options only have meaning at mount time and shouldn't persist across
665 * remounts, or be displayed. Clear these at the end of mount and remount code
666 * paths.
667 */
btrfs_clear_oneshot_options(struct btrfs_fs_info * fs_info)668 static void btrfs_clear_oneshot_options(struct btrfs_fs_info *fs_info)
669 {
670 btrfs_clear_opt(fs_info->mount_opt, USEBACKUPROOT);
671 btrfs_clear_opt(fs_info->mount_opt, CLEAR_CACHE);
672 btrfs_clear_opt(fs_info->mount_opt, NOSPACECACHE);
673 }
674
check_ro_option(const struct btrfs_fs_info * fs_info,unsigned long long mount_opt,unsigned long long opt,const char * opt_name)675 static bool check_ro_option(const struct btrfs_fs_info *fs_info,
676 unsigned long long mount_opt, unsigned long long opt,
677 const char *opt_name)
678 {
679 if (mount_opt & opt) {
680 btrfs_err(fs_info, "%s must be used with ro mount option",
681 opt_name);
682 return true;
683 }
684 return false;
685 }
686
btrfs_check_options(const struct btrfs_fs_info * info,unsigned long long * mount_opt,unsigned long flags)687 bool btrfs_check_options(const struct btrfs_fs_info *info,
688 unsigned long long *mount_opt,
689 unsigned long flags)
690 {
691 bool ret = true;
692
693 if (!(flags & SB_RDONLY) &&
694 (check_ro_option(info, *mount_opt, BTRFS_MOUNT_NOLOGREPLAY, "nologreplay") ||
695 check_ro_option(info, *mount_opt, BTRFS_MOUNT_IGNOREBADROOTS, "ignorebadroots") ||
696 check_ro_option(info, *mount_opt, BTRFS_MOUNT_IGNOREDATACSUMS, "ignoredatacsums") ||
697 check_ro_option(info, *mount_opt, BTRFS_MOUNT_IGNOREMETACSUMS, "ignoremetacsums") ||
698 check_ro_option(info, *mount_opt, BTRFS_MOUNT_IGNORESUPERFLAGS, "ignoresuperflags")))
699 ret = false;
700
701 if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE) &&
702 !btrfs_raw_test_opt(*mount_opt, FREE_SPACE_TREE) &&
703 !btrfs_raw_test_opt(*mount_opt, CLEAR_CACHE)) {
704 btrfs_err(info, "cannot disable free-space-tree");
705 ret = false;
706 }
707 if (btrfs_fs_compat_ro(info, BLOCK_GROUP_TREE) &&
708 !btrfs_raw_test_opt(*mount_opt, FREE_SPACE_TREE)) {
709 btrfs_err(info, "cannot disable free-space-tree with block-group-tree feature");
710 ret = false;
711 }
712
713 if (btrfs_check_mountopts_zoned(info, mount_opt))
714 ret = false;
715
716 if (!test_bit(BTRFS_FS_STATE_REMOUNTING, &info->fs_state)) {
717 if (btrfs_raw_test_opt(*mount_opt, SPACE_CACHE)) {
718 btrfs_warn(info,
719 "space cache v1 is being deprecated and will be removed in a future release, please use -o space_cache=v2");
720 }
721 }
722
723 return ret;
724 }
725
726 /*
727 * This is subtle, we only call this during open_ctree(). We need to pre-load
728 * the mount options with the on-disk settings. Before the new mount API took
729 * effect we would do this on mount and remount. With the new mount API we'll
730 * only do this on the initial mount.
731 *
732 * This isn't a change in behavior, because we're using the current state of the
733 * file system to set the current mount options. If you mounted with special
734 * options to disable these features and then remounted we wouldn't revert the
735 * settings, because mounting without these features cleared the on-disk
736 * settings, so this being called on re-mount is not needed.
737 */
btrfs_set_free_space_cache_settings(struct btrfs_fs_info * fs_info)738 void btrfs_set_free_space_cache_settings(struct btrfs_fs_info *fs_info)
739 {
740 if (fs_info->sectorsize < PAGE_SIZE) {
741 btrfs_clear_opt(fs_info->mount_opt, SPACE_CACHE);
742 if (!btrfs_test_opt(fs_info, FREE_SPACE_TREE)) {
743 btrfs_info(fs_info,
744 "forcing free space tree for sector size %u with page size %lu",
745 fs_info->sectorsize, PAGE_SIZE);
746 btrfs_set_opt(fs_info->mount_opt, FREE_SPACE_TREE);
747 }
748 }
749
750 /*
751 * At this point our mount options are populated, so we only mess with
752 * these settings if we don't have any settings already.
753 */
754 if (btrfs_test_opt(fs_info, FREE_SPACE_TREE))
755 return;
756
757 if (btrfs_is_zoned(fs_info) &&
758 btrfs_free_space_cache_v1_active(fs_info)) {
759 btrfs_info(fs_info, "zoned: clearing existing space cache");
760 btrfs_set_super_cache_generation(fs_info->super_copy, 0);
761 return;
762 }
763
764 if (btrfs_test_opt(fs_info, SPACE_CACHE))
765 return;
766
767 if (btrfs_test_opt(fs_info, NOSPACECACHE))
768 return;
769
770 /*
771 * At this point we don't have explicit options set by the user, set
772 * them ourselves based on the state of the file system.
773 */
774 if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
775 btrfs_set_opt(fs_info->mount_opt, FREE_SPACE_TREE);
776 else if (btrfs_free_space_cache_v1_active(fs_info))
777 btrfs_set_opt(fs_info->mount_opt, SPACE_CACHE);
778 }
779
set_device_specific_options(struct btrfs_fs_info * fs_info)780 static void set_device_specific_options(struct btrfs_fs_info *fs_info)
781 {
782 if (!btrfs_test_opt(fs_info, NOSSD) &&
783 !fs_info->fs_devices->rotating)
784 btrfs_set_opt(fs_info->mount_opt, SSD);
785
786 /*
787 * For devices supporting discard turn on discard=async automatically,
788 * unless it's already set or disabled. This could be turned off by
789 * nodiscard for the same mount.
790 *
791 * The zoned mode piggy backs on the discard functionality for
792 * resetting a zone. There is no reason to delay the zone reset as it is
793 * fast enough. So, do not enable async discard for zoned mode.
794 */
795 if (!(btrfs_test_opt(fs_info, DISCARD_SYNC) ||
796 btrfs_test_opt(fs_info, DISCARD_ASYNC) ||
797 btrfs_test_opt(fs_info, NODISCARD)) &&
798 fs_info->fs_devices->discardable &&
799 !btrfs_is_zoned(fs_info))
800 btrfs_set_opt(fs_info->mount_opt, DISCARD_ASYNC);
801 }
802
btrfs_get_subvol_name_from_objectid(struct btrfs_fs_info * fs_info,u64 subvol_objectid)803 char *btrfs_get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
804 u64 subvol_objectid)
805 {
806 struct btrfs_root *root = fs_info->tree_root;
807 struct btrfs_root *fs_root = NULL;
808 struct btrfs_root_ref *root_ref;
809 struct btrfs_inode_ref *inode_ref;
810 struct btrfs_key key;
811 struct btrfs_path *path = NULL;
812 char *name = NULL, *ptr;
813 u64 dirid;
814 int len;
815 int ret;
816
817 path = btrfs_alloc_path();
818 if (!path) {
819 ret = -ENOMEM;
820 goto err;
821 }
822
823 name = kmalloc(PATH_MAX, GFP_KERNEL);
824 if (!name) {
825 ret = -ENOMEM;
826 goto err;
827 }
828 ptr = name + PATH_MAX - 1;
829 ptr[0] = '\0';
830
831 /*
832 * Walk up the subvolume trees in the tree of tree roots by root
833 * backrefs until we hit the top-level subvolume.
834 */
835 while (subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
836 key.objectid = subvol_objectid;
837 key.type = BTRFS_ROOT_BACKREF_KEY;
838 key.offset = (u64)-1;
839
840 ret = btrfs_search_backwards(root, &key, path);
841 if (ret < 0) {
842 goto err;
843 } else if (ret > 0) {
844 ret = -ENOENT;
845 goto err;
846 }
847
848 subvol_objectid = key.offset;
849
850 root_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
851 struct btrfs_root_ref);
852 len = btrfs_root_ref_name_len(path->nodes[0], root_ref);
853 ptr -= len + 1;
854 if (ptr < name) {
855 ret = -ENAMETOOLONG;
856 goto err;
857 }
858 read_extent_buffer(path->nodes[0], ptr + 1,
859 (unsigned long)(root_ref + 1), len);
860 ptr[0] = '/';
861 dirid = btrfs_root_ref_dirid(path->nodes[0], root_ref);
862 btrfs_release_path(path);
863
864 fs_root = btrfs_get_fs_root(fs_info, subvol_objectid, true);
865 if (IS_ERR(fs_root)) {
866 ret = PTR_ERR(fs_root);
867 fs_root = NULL;
868 goto err;
869 }
870
871 /*
872 * Walk up the filesystem tree by inode refs until we hit the
873 * root directory.
874 */
875 while (dirid != BTRFS_FIRST_FREE_OBJECTID) {
876 key.objectid = dirid;
877 key.type = BTRFS_INODE_REF_KEY;
878 key.offset = (u64)-1;
879
880 ret = btrfs_search_backwards(fs_root, &key, path);
881 if (ret < 0) {
882 goto err;
883 } else if (ret > 0) {
884 ret = -ENOENT;
885 goto err;
886 }
887
888 dirid = key.offset;
889
890 inode_ref = btrfs_item_ptr(path->nodes[0],
891 path->slots[0],
892 struct btrfs_inode_ref);
893 len = btrfs_inode_ref_name_len(path->nodes[0],
894 inode_ref);
895 ptr -= len + 1;
896 if (ptr < name) {
897 ret = -ENAMETOOLONG;
898 goto err;
899 }
900 read_extent_buffer(path->nodes[0], ptr + 1,
901 (unsigned long)(inode_ref + 1), len);
902 ptr[0] = '/';
903 btrfs_release_path(path);
904 }
905 btrfs_put_root(fs_root);
906 fs_root = NULL;
907 }
908
909 btrfs_free_path(path);
910 if (ptr == name + PATH_MAX - 1) {
911 name[0] = '/';
912 name[1] = '\0';
913 } else {
914 memmove(name, ptr, name + PATH_MAX - ptr);
915 }
916 return name;
917
918 err:
919 btrfs_put_root(fs_root);
920 btrfs_free_path(path);
921 kfree(name);
922 return ERR_PTR(ret);
923 }
924
get_default_subvol_objectid(struct btrfs_fs_info * fs_info,u64 * objectid)925 static int get_default_subvol_objectid(struct btrfs_fs_info *fs_info, u64 *objectid)
926 {
927 struct btrfs_root *root = fs_info->tree_root;
928 struct btrfs_dir_item *di;
929 struct btrfs_path *path;
930 struct btrfs_key location;
931 struct fscrypt_str name = FSTR_INIT("default", 7);
932 u64 dir_id;
933
934 path = btrfs_alloc_path();
935 if (!path)
936 return -ENOMEM;
937
938 /*
939 * Find the "default" dir item which points to the root item that we
940 * will mount by default if we haven't been given a specific subvolume
941 * to mount.
942 */
943 dir_id = btrfs_super_root_dir(fs_info->super_copy);
944 di = btrfs_lookup_dir_item(NULL, root, path, dir_id, &name, 0);
945 if (IS_ERR(di)) {
946 btrfs_free_path(path);
947 return PTR_ERR(di);
948 }
949 if (!di) {
950 /*
951 * Ok the default dir item isn't there. This is weird since
952 * it's always been there, but don't freak out, just try and
953 * mount the top-level subvolume.
954 */
955 btrfs_free_path(path);
956 *objectid = BTRFS_FS_TREE_OBJECTID;
957 return 0;
958 }
959
960 btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
961 btrfs_free_path(path);
962 *objectid = location.objectid;
963 return 0;
964 }
965
btrfs_fill_super(struct super_block * sb,struct btrfs_fs_devices * fs_devices)966 static int btrfs_fill_super(struct super_block *sb,
967 struct btrfs_fs_devices *fs_devices)
968 {
969 struct btrfs_inode *inode;
970 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
971 int ret;
972
973 sb->s_maxbytes = MAX_LFS_FILESIZE;
974 sb->s_magic = BTRFS_SUPER_MAGIC;
975 sb->s_op = &btrfs_super_ops;
976 set_default_d_op(sb, &btrfs_dentry_operations);
977 sb->s_export_op = &btrfs_export_ops;
978 #ifdef CONFIG_FS_VERITY
979 sb->s_vop = &btrfs_verityops;
980 #endif
981 sb->s_xattr = btrfs_xattr_handlers;
982 sb->s_time_gran = 1;
983 sb->s_iflags |= SB_I_CGROUPWB | SB_I_ALLOW_HSM;
984
985 ret = super_setup_bdi(sb);
986 if (ret) {
987 btrfs_err(fs_info, "super_setup_bdi failed");
988 return ret;
989 }
990
991 ret = open_ctree(sb, fs_devices);
992 if (ret) {
993 btrfs_err(fs_info, "open_ctree failed: %d", ret);
994 return ret;
995 }
996
997 btrfs_emit_options(fs_info, NULL);
998
999 inode = btrfs_iget(BTRFS_FIRST_FREE_OBJECTID, fs_info->fs_root);
1000 if (IS_ERR(inode)) {
1001 ret = PTR_ERR(inode);
1002 btrfs_handle_fs_error(fs_info, ret, NULL);
1003 goto fail_close;
1004 }
1005
1006 sb->s_root = d_make_root(&inode->vfs_inode);
1007 if (!sb->s_root) {
1008 ret = -ENOMEM;
1009 goto fail_close;
1010 }
1011
1012 sb->s_flags |= SB_ACTIVE;
1013 return 0;
1014
1015 fail_close:
1016 close_ctree(fs_info);
1017 return ret;
1018 }
1019
btrfs_sync_fs(struct super_block * sb,int wait)1020 int btrfs_sync_fs(struct super_block *sb, int wait)
1021 {
1022 struct btrfs_trans_handle *trans;
1023 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1024 struct btrfs_root *root = fs_info->tree_root;
1025
1026 trace_btrfs_sync_fs(fs_info, wait);
1027
1028 if (!wait) {
1029 filemap_flush(fs_info->btree_inode->i_mapping);
1030 return 0;
1031 }
1032
1033 btrfs_wait_ordered_roots(fs_info, U64_MAX, NULL);
1034
1035 trans = btrfs_attach_transaction_barrier(root);
1036 if (IS_ERR(trans)) {
1037 /* no transaction, don't bother */
1038 if (PTR_ERR(trans) == -ENOENT) {
1039 /*
1040 * Exit unless we have some pending changes
1041 * that need to go through commit
1042 */
1043 if (!test_bit(BTRFS_FS_NEED_TRANS_COMMIT,
1044 &fs_info->flags))
1045 return 0;
1046 /*
1047 * A non-blocking test if the fs is frozen. We must not
1048 * start a new transaction here otherwise a deadlock
1049 * happens. The pending operations are delayed to the
1050 * next commit after thawing.
1051 */
1052 if (sb_start_write_trylock(sb))
1053 sb_end_write(sb);
1054 else
1055 return 0;
1056 trans = btrfs_start_transaction(root, 0);
1057 }
1058 if (IS_ERR(trans))
1059 return PTR_ERR(trans);
1060 }
1061 return btrfs_commit_transaction(trans);
1062 }
1063
print_rescue_option(struct seq_file * seq,const char * s,bool * printed)1064 static void print_rescue_option(struct seq_file *seq, const char *s, bool *printed)
1065 {
1066 seq_printf(seq, "%s%s", (*printed) ? ":" : ",rescue=", s);
1067 *printed = true;
1068 }
1069
btrfs_show_options(struct seq_file * seq,struct dentry * dentry)1070 static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
1071 {
1072 struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
1073 const char *compress_type;
1074 const char *subvol_name;
1075 bool printed = false;
1076
1077 if (btrfs_test_opt(info, DEGRADED))
1078 seq_puts(seq, ",degraded");
1079 if (btrfs_test_opt(info, NODATASUM))
1080 seq_puts(seq, ",nodatasum");
1081 if (btrfs_test_opt(info, NODATACOW))
1082 seq_puts(seq, ",nodatacow");
1083 if (btrfs_test_opt(info, NOBARRIER))
1084 seq_puts(seq, ",nobarrier");
1085 if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE)
1086 seq_printf(seq, ",max_inline=%llu", info->max_inline);
1087 if (info->thread_pool_size != min_t(unsigned long,
1088 num_online_cpus() + 2, 8))
1089 seq_printf(seq, ",thread_pool=%u", info->thread_pool_size);
1090 if (btrfs_test_opt(info, COMPRESS)) {
1091 compress_type = btrfs_compress_type2str(info->compress_type);
1092 if (btrfs_test_opt(info, FORCE_COMPRESS))
1093 seq_printf(seq, ",compress-force=%s", compress_type);
1094 else
1095 seq_printf(seq, ",compress=%s", compress_type);
1096 if (info->compress_level && info->compress_type != BTRFS_COMPRESS_LZO)
1097 seq_printf(seq, ":%d", info->compress_level);
1098 }
1099 if (btrfs_test_opt(info, NOSSD))
1100 seq_puts(seq, ",nossd");
1101 if (btrfs_test_opt(info, SSD_SPREAD))
1102 seq_puts(seq, ",ssd_spread");
1103 else if (btrfs_test_opt(info, SSD))
1104 seq_puts(seq, ",ssd");
1105 if (btrfs_test_opt(info, NOTREELOG))
1106 seq_puts(seq, ",notreelog");
1107 if (btrfs_test_opt(info, NOLOGREPLAY))
1108 print_rescue_option(seq, "nologreplay", &printed);
1109 if (btrfs_test_opt(info, USEBACKUPROOT))
1110 print_rescue_option(seq, "usebackuproot", &printed);
1111 if (btrfs_test_opt(info, IGNOREBADROOTS))
1112 print_rescue_option(seq, "ignorebadroots", &printed);
1113 if (btrfs_test_opt(info, IGNOREDATACSUMS))
1114 print_rescue_option(seq, "ignoredatacsums", &printed);
1115 if (btrfs_test_opt(info, IGNOREMETACSUMS))
1116 print_rescue_option(seq, "ignoremetacsums", &printed);
1117 if (btrfs_test_opt(info, IGNORESUPERFLAGS))
1118 print_rescue_option(seq, "ignoresuperflags", &printed);
1119 if (btrfs_test_opt(info, FLUSHONCOMMIT))
1120 seq_puts(seq, ",flushoncommit");
1121 if (btrfs_test_opt(info, DISCARD_SYNC))
1122 seq_puts(seq, ",discard");
1123 if (btrfs_test_opt(info, DISCARD_ASYNC))
1124 seq_puts(seq, ",discard=async");
1125 if (!(info->sb->s_flags & SB_POSIXACL))
1126 seq_puts(seq, ",noacl");
1127 if (btrfs_free_space_cache_v1_active(info))
1128 seq_puts(seq, ",space_cache");
1129 else if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE))
1130 seq_puts(seq, ",space_cache=v2");
1131 else
1132 seq_puts(seq, ",nospace_cache");
1133 if (btrfs_test_opt(info, RESCAN_UUID_TREE))
1134 seq_puts(seq, ",rescan_uuid_tree");
1135 if (btrfs_test_opt(info, CLEAR_CACHE))
1136 seq_puts(seq, ",clear_cache");
1137 if (btrfs_test_opt(info, USER_SUBVOL_RM_ALLOWED))
1138 seq_puts(seq, ",user_subvol_rm_allowed");
1139 if (btrfs_test_opt(info, ENOSPC_DEBUG))
1140 seq_puts(seq, ",enospc_debug");
1141 if (btrfs_test_opt(info, AUTO_DEFRAG))
1142 seq_puts(seq, ",autodefrag");
1143 if (btrfs_test_opt(info, SKIP_BALANCE))
1144 seq_puts(seq, ",skip_balance");
1145 if (info->metadata_ratio)
1146 seq_printf(seq, ",metadata_ratio=%u", info->metadata_ratio);
1147 if (btrfs_test_opt(info, PANIC_ON_FATAL_ERROR))
1148 seq_puts(seq, ",fatal_errors=panic");
1149 if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL)
1150 seq_printf(seq, ",commit=%u", info->commit_interval);
1151 #ifdef CONFIG_BTRFS_DEBUG
1152 if (btrfs_test_opt(info, FRAGMENT_DATA))
1153 seq_puts(seq, ",fragment=data");
1154 if (btrfs_test_opt(info, FRAGMENT_METADATA))
1155 seq_puts(seq, ",fragment=metadata");
1156 #endif
1157 if (btrfs_test_opt(info, REF_VERIFY))
1158 seq_puts(seq, ",ref_verify");
1159 seq_printf(seq, ",subvolid=%llu", btrfs_root_id(BTRFS_I(d_inode(dentry))->root));
1160 subvol_name = btrfs_get_subvol_name_from_objectid(info,
1161 btrfs_root_id(BTRFS_I(d_inode(dentry))->root));
1162 if (!IS_ERR(subvol_name)) {
1163 seq_show_option(seq, "subvol", subvol_name);
1164 kfree(subvol_name);
1165 }
1166 return 0;
1167 }
1168
1169 /*
1170 * subvolumes are identified by ino 256
1171 */
is_subvolume_inode(struct inode * inode)1172 static inline bool is_subvolume_inode(struct inode *inode)
1173 {
1174 if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
1175 return true;
1176 return false;
1177 }
1178
mount_subvol(const char * subvol_name,u64 subvol_objectid,struct vfsmount * mnt)1179 static struct dentry *mount_subvol(const char *subvol_name, u64 subvol_objectid,
1180 struct vfsmount *mnt)
1181 {
1182 struct dentry *root;
1183 int ret;
1184
1185 if (!subvol_name) {
1186 if (!subvol_objectid) {
1187 ret = get_default_subvol_objectid(btrfs_sb(mnt->mnt_sb),
1188 &subvol_objectid);
1189 if (ret) {
1190 root = ERR_PTR(ret);
1191 goto out;
1192 }
1193 }
1194 subvol_name = btrfs_get_subvol_name_from_objectid(
1195 btrfs_sb(mnt->mnt_sb), subvol_objectid);
1196 if (IS_ERR(subvol_name)) {
1197 root = ERR_CAST(subvol_name);
1198 subvol_name = NULL;
1199 goto out;
1200 }
1201
1202 }
1203
1204 root = mount_subtree(mnt, subvol_name);
1205 /* mount_subtree() drops our reference on the vfsmount. */
1206 mnt = NULL;
1207
1208 if (!IS_ERR(root)) {
1209 struct super_block *s = root->d_sb;
1210 struct btrfs_fs_info *fs_info = btrfs_sb(s);
1211 struct inode *root_inode = d_inode(root);
1212 u64 root_objectid = btrfs_root_id(BTRFS_I(root_inode)->root);
1213
1214 ret = 0;
1215 if (!is_subvolume_inode(root_inode)) {
1216 btrfs_err(fs_info, "'%s' is not a valid subvolume",
1217 subvol_name);
1218 ret = -EINVAL;
1219 }
1220 if (subvol_objectid && root_objectid != subvol_objectid) {
1221 /*
1222 * This will also catch a race condition where a
1223 * subvolume which was passed by ID is renamed and
1224 * another subvolume is renamed over the old location.
1225 */
1226 btrfs_err(fs_info,
1227 "subvol '%s' does not match subvolid %llu",
1228 subvol_name, subvol_objectid);
1229 ret = -EINVAL;
1230 }
1231 if (ret) {
1232 dput(root);
1233 root = ERR_PTR(ret);
1234 deactivate_locked_super(s);
1235 }
1236 }
1237
1238 out:
1239 mntput(mnt);
1240 kfree(subvol_name);
1241 return root;
1242 }
1243
btrfs_resize_thread_pool(struct btrfs_fs_info * fs_info,u32 new_pool_size,u32 old_pool_size)1244 static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
1245 u32 new_pool_size, u32 old_pool_size)
1246 {
1247 if (new_pool_size == old_pool_size)
1248 return;
1249
1250 fs_info->thread_pool_size = new_pool_size;
1251
1252 btrfs_info(fs_info, "resize thread pool %d -> %d",
1253 old_pool_size, new_pool_size);
1254
1255 btrfs_workqueue_set_max(fs_info->workers, new_pool_size);
1256 btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size);
1257 btrfs_workqueue_set_max(fs_info->caching_workers, new_pool_size);
1258 workqueue_set_max_active(fs_info->endio_workers, new_pool_size);
1259 workqueue_set_max_active(fs_info->endio_meta_workers, new_pool_size);
1260 btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size);
1261 btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
1262 btrfs_workqueue_set_max(fs_info->delayed_workers, new_pool_size);
1263 }
1264
btrfs_remount_begin(struct btrfs_fs_info * fs_info,unsigned long long old_opts,int flags)1265 static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info,
1266 unsigned long long old_opts, int flags)
1267 {
1268 if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1269 (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1270 (flags & SB_RDONLY))) {
1271 /* wait for any defraggers to finish */
1272 wait_event(fs_info->transaction_wait,
1273 (atomic_read(&fs_info->defrag_running) == 0));
1274 if (flags & SB_RDONLY)
1275 sync_filesystem(fs_info->sb);
1276 }
1277 }
1278
btrfs_remount_cleanup(struct btrfs_fs_info * fs_info,unsigned long long old_opts)1279 static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
1280 unsigned long long old_opts)
1281 {
1282 const bool cache_opt = btrfs_test_opt(fs_info, SPACE_CACHE);
1283
1284 /*
1285 * We need to cleanup all defragable inodes if the autodefragment is
1286 * close or the filesystem is read only.
1287 */
1288 if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1289 (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) || sb_rdonly(fs_info->sb))) {
1290 btrfs_cleanup_defrag_inodes(fs_info);
1291 }
1292
1293 /* If we toggled discard async */
1294 if (!btrfs_raw_test_opt(old_opts, DISCARD_ASYNC) &&
1295 btrfs_test_opt(fs_info, DISCARD_ASYNC))
1296 btrfs_discard_resume(fs_info);
1297 else if (btrfs_raw_test_opt(old_opts, DISCARD_ASYNC) &&
1298 !btrfs_test_opt(fs_info, DISCARD_ASYNC))
1299 btrfs_discard_cleanup(fs_info);
1300
1301 /* If we toggled space cache */
1302 if (cache_opt != btrfs_free_space_cache_v1_active(fs_info))
1303 btrfs_set_free_space_cache_v1_active(fs_info, cache_opt);
1304 }
1305
btrfs_remount_rw(struct btrfs_fs_info * fs_info)1306 static int btrfs_remount_rw(struct btrfs_fs_info *fs_info)
1307 {
1308 int ret;
1309
1310 if (BTRFS_FS_ERROR(fs_info)) {
1311 btrfs_err(fs_info,
1312 "remounting read-write after error is not allowed");
1313 return -EINVAL;
1314 }
1315
1316 if (fs_info->fs_devices->rw_devices == 0)
1317 return -EACCES;
1318
1319 if (!btrfs_check_rw_degradable(fs_info, NULL)) {
1320 btrfs_warn(fs_info,
1321 "too many missing devices, writable remount is not allowed");
1322 return -EACCES;
1323 }
1324
1325 if (btrfs_super_log_root(fs_info->super_copy) != 0) {
1326 btrfs_warn(fs_info,
1327 "mount required to replay tree-log, cannot remount read-write");
1328 return -EINVAL;
1329 }
1330
1331 /*
1332 * NOTE: when remounting with a change that does writes, don't put it
1333 * anywhere above this point, as we are not sure to be safe to write
1334 * until we pass the above checks.
1335 */
1336 ret = btrfs_start_pre_rw_mount(fs_info);
1337 if (ret)
1338 return ret;
1339
1340 btrfs_clear_sb_rdonly(fs_info->sb);
1341
1342 set_bit(BTRFS_FS_OPEN, &fs_info->flags);
1343
1344 /*
1345 * If we've gone from readonly -> read-write, we need to get our
1346 * sync/async discard lists in the right state.
1347 */
1348 btrfs_discard_resume(fs_info);
1349
1350 return 0;
1351 }
1352
btrfs_remount_ro(struct btrfs_fs_info * fs_info)1353 static int btrfs_remount_ro(struct btrfs_fs_info *fs_info)
1354 {
1355 /*
1356 * This also happens on 'umount -rf' or on shutdown, when the
1357 * filesystem is busy.
1358 */
1359 cancel_work_sync(&fs_info->async_reclaim_work);
1360 cancel_work_sync(&fs_info->async_data_reclaim_work);
1361
1362 btrfs_discard_cleanup(fs_info);
1363
1364 /* Wait for the uuid_scan task to finish */
1365 down(&fs_info->uuid_tree_rescan_sem);
1366 /* Avoid complains from lockdep et al. */
1367 up(&fs_info->uuid_tree_rescan_sem);
1368
1369 btrfs_set_sb_rdonly(fs_info->sb);
1370
1371 /*
1372 * Setting SB_RDONLY will put the cleaner thread to sleep at the next
1373 * loop if it's already active. If it's already asleep, we'll leave
1374 * unused block groups on disk until we're mounted read-write again
1375 * unless we clean them up here.
1376 */
1377 btrfs_delete_unused_bgs(fs_info);
1378
1379 /*
1380 * The cleaner task could be already running before we set the flag
1381 * BTRFS_FS_STATE_RO (and SB_RDONLY in the superblock). We must make
1382 * sure that after we finish the remount, i.e. after we call
1383 * btrfs_commit_super(), the cleaner can no longer start a transaction
1384 * - either because it was dropping a dead root, running delayed iputs
1385 * or deleting an unused block group (the cleaner picked a block
1386 * group from the list of unused block groups before we were able to
1387 * in the previous call to btrfs_delete_unused_bgs()).
1388 */
1389 wait_on_bit(&fs_info->flags, BTRFS_FS_CLEANER_RUNNING, TASK_UNINTERRUPTIBLE);
1390
1391 /*
1392 * We've set the superblock to RO mode, so we might have made the
1393 * cleaner task sleep without running all pending delayed iputs. Go
1394 * through all the delayed iputs here, so that if an unmount happens
1395 * without remounting RW we don't end up at finishing close_ctree()
1396 * with a non-empty list of delayed iputs.
1397 */
1398 btrfs_run_delayed_iputs(fs_info);
1399
1400 btrfs_dev_replace_suspend_for_unmount(fs_info);
1401 btrfs_scrub_cancel(fs_info);
1402 btrfs_pause_balance(fs_info);
1403
1404 /*
1405 * Pause the qgroup rescan worker if it is running. We don't want it to
1406 * be still running after we are in RO mode, as after that, by the time
1407 * we unmount, it might have left a transaction open, so we would leak
1408 * the transaction and/or crash.
1409 */
1410 btrfs_qgroup_wait_for_completion(fs_info, false);
1411
1412 return btrfs_commit_super(fs_info);
1413 }
1414
btrfs_ctx_to_info(struct btrfs_fs_info * fs_info,struct btrfs_fs_context * ctx)1415 static void btrfs_ctx_to_info(struct btrfs_fs_info *fs_info, struct btrfs_fs_context *ctx)
1416 {
1417 fs_info->max_inline = ctx->max_inline;
1418 fs_info->commit_interval = ctx->commit_interval;
1419 fs_info->metadata_ratio = ctx->metadata_ratio;
1420 fs_info->thread_pool_size = ctx->thread_pool_size;
1421 fs_info->mount_opt = ctx->mount_opt;
1422 fs_info->compress_type = ctx->compress_type;
1423 fs_info->compress_level = ctx->compress_level;
1424 }
1425
btrfs_info_to_ctx(struct btrfs_fs_info * fs_info,struct btrfs_fs_context * ctx)1426 static void btrfs_info_to_ctx(struct btrfs_fs_info *fs_info, struct btrfs_fs_context *ctx)
1427 {
1428 ctx->max_inline = fs_info->max_inline;
1429 ctx->commit_interval = fs_info->commit_interval;
1430 ctx->metadata_ratio = fs_info->metadata_ratio;
1431 ctx->thread_pool_size = fs_info->thread_pool_size;
1432 ctx->mount_opt = fs_info->mount_opt;
1433 ctx->compress_type = fs_info->compress_type;
1434 ctx->compress_level = fs_info->compress_level;
1435 }
1436
1437 #define btrfs_info_if_set(fs_info, old_ctx, opt, fmt, args...) \
1438 do { \
1439 if ((!old_ctx || !btrfs_raw_test_opt(old_ctx->mount_opt, opt)) && \
1440 btrfs_raw_test_opt(fs_info->mount_opt, opt)) \
1441 btrfs_info(fs_info, fmt, ##args); \
1442 } while (0)
1443
1444 #define btrfs_info_if_unset(fs_info, old_ctx, opt, fmt, args...) \
1445 do { \
1446 if ((old_ctx && btrfs_raw_test_opt(old_ctx->mount_opt, opt)) && \
1447 !btrfs_raw_test_opt(fs_info->mount_opt, opt)) \
1448 btrfs_info(fs_info, fmt, ##args); \
1449 } while (0)
1450
btrfs_emit_options(struct btrfs_fs_info * info,struct btrfs_fs_context * old)1451 static void btrfs_emit_options(struct btrfs_fs_info *info,
1452 struct btrfs_fs_context *old)
1453 {
1454 btrfs_info_if_set(info, old, NODATASUM, "setting nodatasum");
1455 btrfs_info_if_set(info, old, DEGRADED, "allowing degraded mounts");
1456 btrfs_info_if_set(info, old, NODATACOW, "setting nodatacow");
1457 btrfs_info_if_set(info, old, SSD, "enabling ssd optimizations");
1458 btrfs_info_if_set(info, old, SSD_SPREAD, "using spread ssd allocation scheme");
1459 btrfs_info_if_set(info, old, NOBARRIER, "turning off barriers");
1460 btrfs_info_if_set(info, old, NOTREELOG, "disabling tree log");
1461 btrfs_info_if_set(info, old, NOLOGREPLAY, "disabling log replay at mount time");
1462 btrfs_info_if_set(info, old, FLUSHONCOMMIT, "turning on flush-on-commit");
1463 btrfs_info_if_set(info, old, DISCARD_SYNC, "turning on sync discard");
1464 btrfs_info_if_set(info, old, DISCARD_ASYNC, "turning on async discard");
1465 btrfs_info_if_set(info, old, FREE_SPACE_TREE, "enabling free space tree");
1466 btrfs_info_if_set(info, old, SPACE_CACHE, "enabling disk space caching");
1467 btrfs_info_if_set(info, old, CLEAR_CACHE, "force clearing of disk cache");
1468 btrfs_info_if_set(info, old, AUTO_DEFRAG, "enabling auto defrag");
1469 btrfs_info_if_set(info, old, FRAGMENT_DATA, "fragmenting data");
1470 btrfs_info_if_set(info, old, FRAGMENT_METADATA, "fragmenting metadata");
1471 btrfs_info_if_set(info, old, REF_VERIFY, "doing ref verification");
1472 btrfs_info_if_set(info, old, USEBACKUPROOT, "trying to use backup root at mount time");
1473 btrfs_info_if_set(info, old, IGNOREBADROOTS, "ignoring bad roots");
1474 btrfs_info_if_set(info, old, IGNOREDATACSUMS, "ignoring data csums");
1475 btrfs_info_if_set(info, old, IGNOREMETACSUMS, "ignoring meta csums");
1476 btrfs_info_if_set(info, old, IGNORESUPERFLAGS, "ignoring unknown super block flags");
1477
1478 btrfs_info_if_unset(info, old, NODATASUM, "setting datasum");
1479 btrfs_info_if_unset(info, old, NODATACOW, "setting datacow");
1480 btrfs_info_if_unset(info, old, SSD, "not using ssd optimizations");
1481 btrfs_info_if_unset(info, old, SSD_SPREAD, "not using spread ssd allocation scheme");
1482 btrfs_info_if_unset(info, old, NOBARRIER, "turning on barriers");
1483 btrfs_info_if_unset(info, old, NOTREELOG, "enabling tree log");
1484 btrfs_info_if_unset(info, old, SPACE_CACHE, "disabling disk space caching");
1485 btrfs_info_if_unset(info, old, FREE_SPACE_TREE, "disabling free space tree");
1486 btrfs_info_if_unset(info, old, AUTO_DEFRAG, "disabling auto defrag");
1487 btrfs_info_if_unset(info, old, COMPRESS, "use no compression");
1488
1489 /* Did the compression settings change? */
1490 if (btrfs_test_opt(info, COMPRESS) &&
1491 (!old ||
1492 old->compress_type != info->compress_type ||
1493 old->compress_level != info->compress_level ||
1494 (!btrfs_raw_test_opt(old->mount_opt, FORCE_COMPRESS) &&
1495 btrfs_raw_test_opt(info->mount_opt, FORCE_COMPRESS)))) {
1496 const char *compress_type = btrfs_compress_type2str(info->compress_type);
1497
1498 btrfs_info(info, "%s %s compression, level %d",
1499 btrfs_test_opt(info, FORCE_COMPRESS) ? "force" : "use",
1500 compress_type, info->compress_level);
1501 }
1502
1503 if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE)
1504 btrfs_info(info, "max_inline set to %llu", info->max_inline);
1505 }
1506
btrfs_reconfigure(struct fs_context * fc)1507 static int btrfs_reconfigure(struct fs_context *fc)
1508 {
1509 struct super_block *sb = fc->root->d_sb;
1510 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1511 struct btrfs_fs_context *ctx = fc->fs_private;
1512 struct btrfs_fs_context old_ctx;
1513 int ret = 0;
1514 bool mount_reconfigure = (fc->s_fs_info != NULL);
1515
1516 btrfs_info_to_ctx(fs_info, &old_ctx);
1517
1518 /*
1519 * This is our "bind mount" trick, we don't want to allow the user to do
1520 * anything other than mount a different ro/rw and a different subvol,
1521 * all of the mount options should be maintained.
1522 */
1523 if (mount_reconfigure)
1524 ctx->mount_opt = old_ctx.mount_opt;
1525
1526 sync_filesystem(sb);
1527 set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1528
1529 if (!btrfs_check_options(fs_info, &ctx->mount_opt, fc->sb_flags))
1530 return -EINVAL;
1531
1532 ret = btrfs_check_features(fs_info, !(fc->sb_flags & SB_RDONLY));
1533 if (ret < 0)
1534 return ret;
1535
1536 btrfs_ctx_to_info(fs_info, ctx);
1537 btrfs_remount_begin(fs_info, old_ctx.mount_opt, fc->sb_flags);
1538 btrfs_resize_thread_pool(fs_info, fs_info->thread_pool_size,
1539 old_ctx.thread_pool_size);
1540
1541 if ((bool)btrfs_test_opt(fs_info, FREE_SPACE_TREE) !=
1542 (bool)btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE) &&
1543 (!sb_rdonly(sb) || (fc->sb_flags & SB_RDONLY))) {
1544 btrfs_warn(fs_info,
1545 "remount supports changing free space tree only from RO to RW");
1546 /* Make sure free space cache options match the state on disk. */
1547 if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE)) {
1548 btrfs_set_opt(fs_info->mount_opt, FREE_SPACE_TREE);
1549 btrfs_clear_opt(fs_info->mount_opt, SPACE_CACHE);
1550 }
1551 if (btrfs_free_space_cache_v1_active(fs_info)) {
1552 btrfs_clear_opt(fs_info->mount_opt, FREE_SPACE_TREE);
1553 btrfs_set_opt(fs_info->mount_opt, SPACE_CACHE);
1554 }
1555 }
1556
1557 ret = 0;
1558 if (!sb_rdonly(sb) && (fc->sb_flags & SB_RDONLY))
1559 ret = btrfs_remount_ro(fs_info);
1560 else if (sb_rdonly(sb) && !(fc->sb_flags & SB_RDONLY))
1561 ret = btrfs_remount_rw(fs_info);
1562 if (ret)
1563 goto restore;
1564
1565 /*
1566 * If we set the mask during the parameter parsing VFS would reject the
1567 * remount. Here we can set the mask and the value will be updated
1568 * appropriately.
1569 */
1570 if ((fc->sb_flags & SB_POSIXACL) != (sb->s_flags & SB_POSIXACL))
1571 fc->sb_flags_mask |= SB_POSIXACL;
1572
1573 btrfs_emit_options(fs_info, &old_ctx);
1574 wake_up_process(fs_info->transaction_kthread);
1575 btrfs_remount_cleanup(fs_info, old_ctx.mount_opt);
1576 btrfs_clear_oneshot_options(fs_info);
1577 clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1578
1579 return 0;
1580 restore:
1581 btrfs_ctx_to_info(fs_info, &old_ctx);
1582 btrfs_remount_cleanup(fs_info, old_ctx.mount_opt);
1583 clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1584 return ret;
1585 }
1586
1587 /* Used to sort the devices by max_avail(descending sort) */
btrfs_cmp_device_free_bytes(const void * a,const void * b)1588 static int btrfs_cmp_device_free_bytes(const void *a, const void *b)
1589 {
1590 const struct btrfs_device_info *dev_info1 = a;
1591 const struct btrfs_device_info *dev_info2 = b;
1592
1593 if (dev_info1->max_avail > dev_info2->max_avail)
1594 return -1;
1595 else if (dev_info1->max_avail < dev_info2->max_avail)
1596 return 1;
1597 return 0;
1598 }
1599
1600 /*
1601 * sort the devices by max_avail, in which max free extent size of each device
1602 * is stored.(Descending Sort)
1603 */
btrfs_descending_sort_devices(struct btrfs_device_info * devices,size_t nr_devices)1604 static inline void btrfs_descending_sort_devices(
1605 struct btrfs_device_info *devices,
1606 size_t nr_devices)
1607 {
1608 sort(devices, nr_devices, sizeof(struct btrfs_device_info),
1609 btrfs_cmp_device_free_bytes, NULL);
1610 }
1611
1612 /*
1613 * The helper to calc the free space on the devices that can be used to store
1614 * file data.
1615 */
btrfs_calc_avail_data_space(struct btrfs_fs_info * fs_info,u64 * free_bytes)1616 static inline int btrfs_calc_avail_data_space(struct btrfs_fs_info *fs_info,
1617 u64 *free_bytes)
1618 {
1619 struct btrfs_device_info *devices_info;
1620 struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
1621 struct btrfs_device *device;
1622 u64 type;
1623 u64 avail_space;
1624 u64 min_stripe_size;
1625 int num_stripes = 1;
1626 int i = 0, nr_devices;
1627 const struct btrfs_raid_attr *rattr;
1628
1629 /*
1630 * We aren't under the device list lock, so this is racy-ish, but good
1631 * enough for our purposes.
1632 */
1633 nr_devices = fs_info->fs_devices->open_devices;
1634 if (!nr_devices) {
1635 smp_mb();
1636 nr_devices = fs_info->fs_devices->open_devices;
1637 ASSERT(nr_devices);
1638 if (!nr_devices) {
1639 *free_bytes = 0;
1640 return 0;
1641 }
1642 }
1643
1644 devices_info = kmalloc_array(nr_devices, sizeof(*devices_info),
1645 GFP_KERNEL);
1646 if (!devices_info)
1647 return -ENOMEM;
1648
1649 /* calc min stripe number for data space allocation */
1650 type = btrfs_data_alloc_profile(fs_info);
1651 rattr = &btrfs_raid_array[btrfs_bg_flags_to_raid_index(type)];
1652
1653 if (type & BTRFS_BLOCK_GROUP_RAID0)
1654 num_stripes = nr_devices;
1655 else if (type & BTRFS_BLOCK_GROUP_RAID1_MASK)
1656 num_stripes = rattr->ncopies;
1657 else if (type & BTRFS_BLOCK_GROUP_RAID10)
1658 num_stripes = 4;
1659
1660 /* Adjust for more than 1 stripe per device */
1661 min_stripe_size = rattr->dev_stripes * BTRFS_STRIPE_LEN;
1662
1663 rcu_read_lock();
1664 list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
1665 if (!test_bit(BTRFS_DEV_STATE_IN_FS_METADATA,
1666 &device->dev_state) ||
1667 !device->bdev ||
1668 test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state))
1669 continue;
1670
1671 if (i >= nr_devices)
1672 break;
1673
1674 avail_space = device->total_bytes - device->bytes_used;
1675
1676 /* align with stripe_len */
1677 avail_space = rounddown(avail_space, BTRFS_STRIPE_LEN);
1678
1679 /*
1680 * Ensure we have at least min_stripe_size on top of the
1681 * reserved space on the device.
1682 */
1683 if (avail_space <= BTRFS_DEVICE_RANGE_RESERVED + min_stripe_size)
1684 continue;
1685
1686 avail_space -= BTRFS_DEVICE_RANGE_RESERVED;
1687
1688 devices_info[i].dev = device;
1689 devices_info[i].max_avail = avail_space;
1690
1691 i++;
1692 }
1693 rcu_read_unlock();
1694
1695 nr_devices = i;
1696
1697 btrfs_descending_sort_devices(devices_info, nr_devices);
1698
1699 i = nr_devices - 1;
1700 avail_space = 0;
1701 while (nr_devices >= rattr->devs_min) {
1702 num_stripes = min(num_stripes, nr_devices);
1703
1704 if (devices_info[i].max_avail >= min_stripe_size) {
1705 int j;
1706 u64 alloc_size;
1707
1708 avail_space += devices_info[i].max_avail * num_stripes;
1709 alloc_size = devices_info[i].max_avail;
1710 for (j = i + 1 - num_stripes; j <= i; j++)
1711 devices_info[j].max_avail -= alloc_size;
1712 }
1713 i--;
1714 nr_devices--;
1715 }
1716
1717 kfree(devices_info);
1718 *free_bytes = avail_space;
1719 return 0;
1720 }
1721
1722 /*
1723 * Calculate numbers for 'df', pessimistic in case of mixed raid profiles.
1724 *
1725 * If there's a redundant raid level at DATA block groups, use the respective
1726 * multiplier to scale the sizes.
1727 *
1728 * Unused device space usage is based on simulating the chunk allocator
1729 * algorithm that respects the device sizes and order of allocations. This is
1730 * a close approximation of the actual use but there are other factors that may
1731 * change the result (like a new metadata chunk).
1732 *
1733 * If metadata is exhausted, f_bavail will be 0.
1734 */
btrfs_statfs(struct dentry * dentry,struct kstatfs * buf)1735 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
1736 {
1737 struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
1738 struct btrfs_super_block *disk_super = fs_info->super_copy;
1739 struct btrfs_space_info *found;
1740 u64 total_used = 0;
1741 u64 total_free_data = 0;
1742 u64 total_free_meta = 0;
1743 u32 bits = fs_info->sectorsize_bits;
1744 __be32 *fsid = (__be32 *)fs_info->fs_devices->fsid;
1745 unsigned factor = 1;
1746 struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
1747 int ret;
1748 u64 thresh = 0;
1749 int mixed = 0;
1750
1751 list_for_each_entry(found, &fs_info->space_info, list) {
1752 if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
1753 int i;
1754
1755 total_free_data += found->disk_total - found->disk_used;
1756 total_free_data -=
1757 btrfs_account_ro_block_groups_free_space(found);
1758
1759 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
1760 if (!list_empty(&found->block_groups[i]))
1761 factor = btrfs_bg_type_to_factor(
1762 btrfs_raid_array[i].bg_flag);
1763 }
1764 }
1765
1766 /*
1767 * Metadata in mixed block group profiles are accounted in data
1768 */
1769 if (!mixed && found->flags & BTRFS_BLOCK_GROUP_METADATA) {
1770 if (found->flags & BTRFS_BLOCK_GROUP_DATA)
1771 mixed = 1;
1772 else
1773 total_free_meta += found->disk_total -
1774 found->disk_used;
1775 }
1776
1777 total_used += found->disk_used;
1778 }
1779
1780 buf->f_blocks = div_u64(btrfs_super_total_bytes(disk_super), factor);
1781 buf->f_blocks >>= bits;
1782 buf->f_bfree = buf->f_blocks - (div_u64(total_used, factor) >> bits);
1783
1784 /* Account global block reserve as used, it's in logical size already */
1785 spin_lock(&block_rsv->lock);
1786 /* Mixed block groups accounting is not byte-accurate, avoid overflow */
1787 if (buf->f_bfree >= block_rsv->size >> bits)
1788 buf->f_bfree -= block_rsv->size >> bits;
1789 else
1790 buf->f_bfree = 0;
1791 spin_unlock(&block_rsv->lock);
1792
1793 buf->f_bavail = div_u64(total_free_data, factor);
1794 ret = btrfs_calc_avail_data_space(fs_info, &total_free_data);
1795 if (ret)
1796 return ret;
1797 buf->f_bavail += div_u64(total_free_data, factor);
1798 buf->f_bavail = buf->f_bavail >> bits;
1799
1800 /*
1801 * We calculate the remaining metadata space minus global reserve. If
1802 * this is (supposedly) smaller than zero, there's no space. But this
1803 * does not hold in practice, the exhausted state happens where's still
1804 * some positive delta. So we apply some guesswork and compare the
1805 * delta to a 4M threshold. (Practically observed delta was ~2M.)
1806 *
1807 * We probably cannot calculate the exact threshold value because this
1808 * depends on the internal reservations requested by various
1809 * operations, so some operations that consume a few metadata will
1810 * succeed even if the Avail is zero. But this is better than the other
1811 * way around.
1812 */
1813 thresh = SZ_4M;
1814
1815 /*
1816 * We only want to claim there's no available space if we can no longer
1817 * allocate chunks for our metadata profile and our global reserve will
1818 * not fit in the free metadata space. If we aren't ->full then we
1819 * still can allocate chunks and thus are fine using the currently
1820 * calculated f_bavail.
1821 */
1822 if (!mixed && block_rsv->space_info->full &&
1823 (total_free_meta < thresh || total_free_meta - thresh < block_rsv->size))
1824 buf->f_bavail = 0;
1825
1826 buf->f_type = BTRFS_SUPER_MAGIC;
1827 buf->f_bsize = fs_info->sectorsize;
1828 buf->f_namelen = BTRFS_NAME_LEN;
1829
1830 /* We treat it as constant endianness (it doesn't matter _which_)
1831 because we want the fsid to come out the same whether mounted
1832 on a big-endian or little-endian host */
1833 buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
1834 buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
1835 /* Mask in the root object ID too, to disambiguate subvols */
1836 buf->f_fsid.val[0] ^= btrfs_root_id(BTRFS_I(d_inode(dentry))->root) >> 32;
1837 buf->f_fsid.val[1] ^= btrfs_root_id(BTRFS_I(d_inode(dentry))->root);
1838
1839 return 0;
1840 }
1841
btrfs_fc_test_super(struct super_block * sb,struct fs_context * fc)1842 static int btrfs_fc_test_super(struct super_block *sb, struct fs_context *fc)
1843 {
1844 struct btrfs_fs_info *p = fc->s_fs_info;
1845 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1846
1847 return fs_info->fs_devices == p->fs_devices;
1848 }
1849
btrfs_get_tree_super(struct fs_context * fc)1850 static int btrfs_get_tree_super(struct fs_context *fc)
1851 {
1852 struct btrfs_fs_info *fs_info = fc->s_fs_info;
1853 struct btrfs_fs_context *ctx = fc->fs_private;
1854 struct btrfs_fs_devices *fs_devices = NULL;
1855 struct btrfs_device *device;
1856 struct super_block *sb;
1857 blk_mode_t mode = sb_open_mode(fc->sb_flags);
1858 int ret;
1859
1860 btrfs_ctx_to_info(fs_info, ctx);
1861 mutex_lock(&uuid_mutex);
1862
1863 /*
1864 * With 'true' passed to btrfs_scan_one_device() (mount time) we expect
1865 * either a valid device or an error.
1866 */
1867 device = btrfs_scan_one_device(fc->source, true);
1868 ASSERT(device != NULL);
1869 if (IS_ERR(device)) {
1870 mutex_unlock(&uuid_mutex);
1871 return PTR_ERR(device);
1872 }
1873 fs_devices = device->fs_devices;
1874 /*
1875 * We cannot hold uuid_mutex calling sget_fc(), it will lead to a
1876 * locking order reversal with s_umount.
1877 *
1878 * So here we increase the holding number of fs_devices, this will ensure
1879 * the fs_devices itself won't be freed.
1880 */
1881 btrfs_fs_devices_inc_holding(fs_devices);
1882 fs_info->fs_devices = fs_devices;
1883 mutex_unlock(&uuid_mutex);
1884
1885
1886 sb = sget_fc(fc, btrfs_fc_test_super, set_anon_super_fc);
1887 if (IS_ERR(sb)) {
1888 mutex_lock(&uuid_mutex);
1889 btrfs_fs_devices_dec_holding(fs_devices);
1890 /*
1891 * Since the fs_devices is not opened, it can be freed at any
1892 * time after unlocking uuid_mutex. We need to avoid double
1893 * free through put_fs_context()->btrfs_free_fs_info().
1894 * So here we reset fs_info->fs_devices to NULL, and let the
1895 * regular fs_devices reclaim path to handle it.
1896 *
1897 * This applies to all later branches where no fs_devices is
1898 * opened.
1899 */
1900 fs_info->fs_devices = NULL;
1901 mutex_unlock(&uuid_mutex);
1902 return PTR_ERR(sb);
1903 }
1904
1905 set_device_specific_options(fs_info);
1906
1907 if (sb->s_root) {
1908 /*
1909 * Not the first mount of the fs thus got an existing super block.
1910 * Will reuse the returned super block, fs_info and fs_devices.
1911 *
1912 * fc->s_fs_info is not touched and will be later freed by
1913 * put_fs_context() through btrfs_free_fs_context().
1914 */
1915 ASSERT(fc->s_fs_info == fs_info);
1916
1917 mutex_lock(&uuid_mutex);
1918 btrfs_fs_devices_dec_holding(fs_devices);
1919 fs_info->fs_devices = NULL;
1920 mutex_unlock(&uuid_mutex);
1921 /*
1922 * At this stage we may have RO flag mismatch between
1923 * fc->sb_flags and sb->s_flags. Caller should detect such
1924 * mismatch and reconfigure with sb->s_umount rwsem held if
1925 * needed.
1926 */
1927 } else {
1928 struct block_device *bdev;
1929
1930 /*
1931 * The first mount of the fs thus a new superblock, fc->s_fs_info
1932 * must be NULL, and the ownership of our fs_info and fs_devices is
1933 * transferred to the super block.
1934 */
1935 ASSERT(fc->s_fs_info == NULL);
1936
1937 mutex_lock(&uuid_mutex);
1938 btrfs_fs_devices_dec_holding(fs_devices);
1939 ret = btrfs_open_devices(fs_devices, mode, sb);
1940 if (ret < 0)
1941 fs_info->fs_devices = NULL;
1942 mutex_unlock(&uuid_mutex);
1943 if (ret < 0) {
1944 deactivate_locked_super(sb);
1945 return ret;
1946 }
1947 if (!(fc->sb_flags & SB_RDONLY) && fs_devices->rw_devices == 0) {
1948 deactivate_locked_super(sb);
1949 return -EACCES;
1950 }
1951 bdev = fs_devices->latest_dev->bdev;
1952 snprintf(sb->s_id, sizeof(sb->s_id), "%pg", bdev);
1953 shrinker_debugfs_rename(sb->s_shrink, "sb-btrfs:%s", sb->s_id);
1954 ret = btrfs_fill_super(sb, fs_devices);
1955 if (ret) {
1956 deactivate_locked_super(sb);
1957 return ret;
1958 }
1959 }
1960
1961 btrfs_clear_oneshot_options(fs_info);
1962
1963 fc->root = dget(sb->s_root);
1964 return 0;
1965 }
1966
1967 /*
1968 * Ever since commit 0723a0473fb4 ("btrfs: allow mounting btrfs subvolumes
1969 * with different ro/rw options") the following works:
1970 *
1971 * (i) mount /dev/sda3 -o subvol=foo,ro /mnt/foo
1972 * (ii) mount /dev/sda3 -o subvol=bar,rw /mnt/bar
1973 *
1974 * which looks nice and innocent but is actually pretty intricate and deserves
1975 * a long comment.
1976 *
1977 * On another filesystem a subvolume mount is close to something like:
1978 *
1979 * (iii) # create rw superblock + initial mount
1980 * mount -t xfs /dev/sdb /opt/
1981 *
1982 * # create ro bind mount
1983 * mount --bind -o ro /opt/foo /mnt/foo
1984 *
1985 * # unmount initial mount
1986 * umount /opt
1987 *
1988 * Of course, there's some special subvolume sauce and there's the fact that the
1989 * sb->s_root dentry is really swapped after mount_subtree(). But conceptually
1990 * it's very close and will help us understand the issue.
1991 *
1992 * The old mount API didn't cleanly distinguish between a mount being made ro
1993 * and a superblock being made ro. The only way to change the ro state of
1994 * either object was by passing ms_rdonly. If a new mount was created via
1995 * mount(2) such as:
1996 *
1997 * mount("/dev/sdb", "/mnt", "xfs", ms_rdonly, null);
1998 *
1999 * the MS_RDONLY flag being specified had two effects:
2000 *
2001 * (1) MNT_READONLY was raised -> the resulting mount got
2002 * @mnt->mnt_flags |= MNT_READONLY raised.
2003 *
2004 * (2) MS_RDONLY was passed to the filesystem's mount method and the filesystems
2005 * made the superblock ro. Note, how SB_RDONLY has the same value as
2006 * ms_rdonly and is raised whenever MS_RDONLY is passed through mount(2).
2007 *
2008 * Creating a subtree mount via (iii) ends up leaving a rw superblock with a
2009 * subtree mounted ro.
2010 *
2011 * But consider the effect on the old mount API on btrfs subvolume mounting
2012 * which combines the distinct step in (iii) into a single step.
2013 *
2014 * By issuing (i) both the mount and the superblock are turned ro. Now when (ii)
2015 * is issued the superblock is ro and thus even if the mount created for (ii) is
2016 * rw it wouldn't help. Hence, btrfs needed to transition the superblock from ro
2017 * to rw for (ii) which it did using an internal remount call.
2018 *
2019 * IOW, subvolume mounting was inherently complicated due to the ambiguity of
2020 * MS_RDONLY in mount(2). Note, this ambiguity has mount(8) always translate
2021 * "ro" to MS_RDONLY. IOW, in both (i) and (ii) "ro" becomes MS_RDONLY when
2022 * passed by mount(8) to mount(2).
2023 *
2024 * Enter the new mount API. The new mount API disambiguates making a mount ro
2025 * and making a superblock ro.
2026 *
2027 * (3) To turn a mount ro the MOUNT_ATTR_ONLY flag can be used with either
2028 * fsmount() or mount_setattr() this is a pure VFS level change for a
2029 * specific mount or mount tree that is never seen by the filesystem itself.
2030 *
2031 * (4) To turn a superblock ro the "ro" flag must be used with
2032 * fsconfig(FSCONFIG_SET_FLAG, "ro"). This option is seen by the filesystem
2033 * in fc->sb_flags.
2034 *
2035 * But, currently the util-linux mount command already utilizes the new mount
2036 * API and is still setting fsconfig(FSCONFIG_SET_FLAG, "ro") no matter if it's
2037 * btrfs or not, setting the whole super block RO. To make per-subvolume mounting
2038 * work with different options work we need to keep backward compatibility.
2039 */
btrfs_reconfigure_for_mount(struct fs_context * fc)2040 static int btrfs_reconfigure_for_mount(struct fs_context *fc)
2041 {
2042 int ret = 0;
2043
2044 if (!(fc->sb_flags & SB_RDONLY) && (fc->root->d_sb->s_flags & SB_RDONLY))
2045 ret = btrfs_reconfigure(fc);
2046
2047 return ret;
2048 }
2049
btrfs_get_tree_subvol(struct fs_context * fc)2050 static int btrfs_get_tree_subvol(struct fs_context *fc)
2051 {
2052 struct btrfs_fs_info *fs_info = NULL;
2053 struct btrfs_fs_context *ctx = fc->fs_private;
2054 struct fs_context *dup_fc;
2055 struct dentry *dentry;
2056 struct vfsmount *mnt;
2057 int ret = 0;
2058
2059 /*
2060 * Setup a dummy root and fs_info for test/set super. This is because
2061 * we don't actually fill this stuff out until open_ctree, but we need
2062 * then open_ctree will properly initialize the file system specific
2063 * settings later. btrfs_init_fs_info initializes the static elements
2064 * of the fs_info (locks and such) to make cleanup easier if we find a
2065 * superblock with our given fs_devices later on at sget() time.
2066 */
2067 fs_info = kvzalloc(sizeof(struct btrfs_fs_info), GFP_KERNEL);
2068 if (!fs_info)
2069 return -ENOMEM;
2070
2071 fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
2072 fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
2073 if (!fs_info->super_copy || !fs_info->super_for_commit) {
2074 btrfs_free_fs_info(fs_info);
2075 return -ENOMEM;
2076 }
2077 btrfs_init_fs_info(fs_info);
2078
2079 dup_fc = vfs_dup_fs_context(fc);
2080 if (IS_ERR(dup_fc)) {
2081 btrfs_free_fs_info(fs_info);
2082 return PTR_ERR(dup_fc);
2083 }
2084
2085 /*
2086 * When we do the sget_fc this gets transferred to the sb, so we only
2087 * need to set it on the dup_fc as this is what creates the super block.
2088 */
2089 dup_fc->s_fs_info = fs_info;
2090
2091 ret = btrfs_get_tree_super(dup_fc);
2092 if (ret)
2093 goto error;
2094
2095 ret = btrfs_reconfigure_for_mount(dup_fc);
2096 up_write(&dup_fc->root->d_sb->s_umount);
2097 if (ret)
2098 goto error;
2099 mnt = vfs_create_mount(dup_fc);
2100 put_fs_context(dup_fc);
2101 if (IS_ERR(mnt))
2102 return PTR_ERR(mnt);
2103
2104 /*
2105 * This free's ->subvol_name, because if it isn't set we have to
2106 * allocate a buffer to hold the subvol_name, so we just drop our
2107 * reference to it here.
2108 */
2109 dentry = mount_subvol(ctx->subvol_name, ctx->subvol_objectid, mnt);
2110 ctx->subvol_name = NULL;
2111 if (IS_ERR(dentry))
2112 return PTR_ERR(dentry);
2113
2114 fc->root = dentry;
2115 return 0;
2116 error:
2117 put_fs_context(dup_fc);
2118 return ret;
2119 }
2120
btrfs_get_tree(struct fs_context * fc)2121 static int btrfs_get_tree(struct fs_context *fc)
2122 {
2123 ASSERT(fc->s_fs_info == NULL);
2124
2125 return btrfs_get_tree_subvol(fc);
2126 }
2127
btrfs_kill_super(struct super_block * sb)2128 static void btrfs_kill_super(struct super_block *sb)
2129 {
2130 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2131 kill_anon_super(sb);
2132 btrfs_free_fs_info(fs_info);
2133 }
2134
btrfs_free_fs_context(struct fs_context * fc)2135 static void btrfs_free_fs_context(struct fs_context *fc)
2136 {
2137 struct btrfs_fs_context *ctx = fc->fs_private;
2138 struct btrfs_fs_info *fs_info = fc->s_fs_info;
2139
2140 if (fs_info)
2141 btrfs_free_fs_info(fs_info);
2142
2143 if (ctx && refcount_dec_and_test(&ctx->refs)) {
2144 kfree(ctx->subvol_name);
2145 kfree(ctx);
2146 }
2147 }
2148
btrfs_dup_fs_context(struct fs_context * fc,struct fs_context * src_fc)2149 static int btrfs_dup_fs_context(struct fs_context *fc, struct fs_context *src_fc)
2150 {
2151 struct btrfs_fs_context *ctx = src_fc->fs_private;
2152
2153 /*
2154 * Give a ref to our ctx to this dup, as we want to keep it around for
2155 * our original fc so we can have the subvolume name or objectid.
2156 *
2157 * We unset ->source in the original fc because the dup needs it for
2158 * mounting, and then once we free the dup it'll free ->source, so we
2159 * need to make sure we're only pointing to it in one fc.
2160 */
2161 refcount_inc(&ctx->refs);
2162 fc->fs_private = ctx;
2163 fc->source = src_fc->source;
2164 src_fc->source = NULL;
2165 return 0;
2166 }
2167
2168 static const struct fs_context_operations btrfs_fs_context_ops = {
2169 .parse_param = btrfs_parse_param,
2170 .reconfigure = btrfs_reconfigure,
2171 .get_tree = btrfs_get_tree,
2172 .dup = btrfs_dup_fs_context,
2173 .free = btrfs_free_fs_context,
2174 };
2175
btrfs_init_fs_context(struct fs_context * fc)2176 static int btrfs_init_fs_context(struct fs_context *fc)
2177 {
2178 struct btrfs_fs_context *ctx;
2179
2180 ctx = kzalloc(sizeof(struct btrfs_fs_context), GFP_KERNEL);
2181 if (!ctx)
2182 return -ENOMEM;
2183
2184 refcount_set(&ctx->refs, 1);
2185 fc->fs_private = ctx;
2186 fc->ops = &btrfs_fs_context_ops;
2187
2188 if (fc->purpose == FS_CONTEXT_FOR_RECONFIGURE) {
2189 btrfs_info_to_ctx(btrfs_sb(fc->root->d_sb), ctx);
2190 } else {
2191 ctx->thread_pool_size =
2192 min_t(unsigned long, num_online_cpus() + 2, 8);
2193 ctx->max_inline = BTRFS_DEFAULT_MAX_INLINE;
2194 ctx->commit_interval = BTRFS_DEFAULT_COMMIT_INTERVAL;
2195 }
2196
2197 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
2198 fc->sb_flags |= SB_POSIXACL;
2199 #endif
2200 fc->sb_flags |= SB_I_VERSION;
2201
2202 return 0;
2203 }
2204
2205 static struct file_system_type btrfs_fs_type = {
2206 .owner = THIS_MODULE,
2207 .name = "btrfs",
2208 .init_fs_context = btrfs_init_fs_context,
2209 .parameters = btrfs_fs_parameters,
2210 .kill_sb = btrfs_kill_super,
2211 .fs_flags = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA |
2212 FS_ALLOW_IDMAP | FS_MGTIME,
2213 };
2214
2215 MODULE_ALIAS_FS("btrfs");
2216
btrfs_control_open(struct inode * inode,struct file * file)2217 static int btrfs_control_open(struct inode *inode, struct file *file)
2218 {
2219 /*
2220 * The control file's private_data is used to hold the
2221 * transaction when it is started and is used to keep
2222 * track of whether a transaction is already in progress.
2223 */
2224 file->private_data = NULL;
2225 return 0;
2226 }
2227
2228 /*
2229 * Used by /dev/btrfs-control for devices ioctls.
2230 */
btrfs_control_ioctl(struct file * file,unsigned int cmd,unsigned long arg)2231 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
2232 unsigned long arg)
2233 {
2234 struct btrfs_ioctl_vol_args *vol;
2235 struct btrfs_device *device = NULL;
2236 dev_t devt = 0;
2237 int ret = -ENOTTY;
2238
2239 if (!capable(CAP_SYS_ADMIN))
2240 return -EPERM;
2241
2242 vol = memdup_user((void __user *)arg, sizeof(*vol));
2243 if (IS_ERR(vol))
2244 return PTR_ERR(vol);
2245 ret = btrfs_check_ioctl_vol_args_path(vol);
2246 if (ret < 0)
2247 goto out;
2248
2249 switch (cmd) {
2250 case BTRFS_IOC_SCAN_DEV:
2251 mutex_lock(&uuid_mutex);
2252 /*
2253 * Scanning outside of mount can return NULL which would turn
2254 * into 0 error code.
2255 */
2256 device = btrfs_scan_one_device(vol->name, false);
2257 ret = PTR_ERR_OR_ZERO(device);
2258 mutex_unlock(&uuid_mutex);
2259 break;
2260 case BTRFS_IOC_FORGET_DEV:
2261 if (vol->name[0] != 0) {
2262 ret = lookup_bdev(vol->name, &devt);
2263 if (ret)
2264 break;
2265 }
2266 ret = btrfs_forget_devices(devt);
2267 break;
2268 case BTRFS_IOC_DEVICES_READY:
2269 mutex_lock(&uuid_mutex);
2270 /*
2271 * Scanning outside of mount can return NULL which would turn
2272 * into 0 error code.
2273 */
2274 device = btrfs_scan_one_device(vol->name, false);
2275 if (IS_ERR_OR_NULL(device)) {
2276 mutex_unlock(&uuid_mutex);
2277 if (IS_ERR(device))
2278 ret = PTR_ERR(device);
2279 else
2280 ret = 0;
2281 break;
2282 }
2283 ret = !(device->fs_devices->num_devices ==
2284 device->fs_devices->total_devices);
2285 mutex_unlock(&uuid_mutex);
2286 break;
2287 case BTRFS_IOC_GET_SUPPORTED_FEATURES:
2288 ret = btrfs_ioctl_get_supported_features((void __user*)arg);
2289 break;
2290 }
2291
2292 out:
2293 kfree(vol);
2294 return ret;
2295 }
2296
btrfs_freeze(struct super_block * sb)2297 static int btrfs_freeze(struct super_block *sb)
2298 {
2299 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2300
2301 set_bit(BTRFS_FS_FROZEN, &fs_info->flags);
2302 /*
2303 * We don't need a barrier here, we'll wait for any transaction that
2304 * could be in progress on other threads (and do delayed iputs that
2305 * we want to avoid on a frozen filesystem), or do the commit
2306 * ourselves.
2307 */
2308 return btrfs_commit_current_transaction(fs_info->tree_root);
2309 }
2310
check_dev_super(struct btrfs_device * dev)2311 static int check_dev_super(struct btrfs_device *dev)
2312 {
2313 struct btrfs_fs_info *fs_info = dev->fs_info;
2314 struct btrfs_super_block *sb;
2315 u64 last_trans;
2316 u16 csum_type;
2317 int ret = 0;
2318
2319 /* This should be called with fs still frozen. */
2320 ASSERT(test_bit(BTRFS_FS_FROZEN, &fs_info->flags));
2321
2322 /* Missing dev, no need to check. */
2323 if (!dev->bdev)
2324 return 0;
2325
2326 /* Only need to check the primary super block. */
2327 sb = btrfs_read_disk_super(dev->bdev, 0, true);
2328 if (IS_ERR(sb))
2329 return PTR_ERR(sb);
2330
2331 /* Verify the checksum. */
2332 csum_type = btrfs_super_csum_type(sb);
2333 if (csum_type != btrfs_super_csum_type(fs_info->super_copy)) {
2334 btrfs_err(fs_info, "csum type changed, has %u expect %u",
2335 csum_type, btrfs_super_csum_type(fs_info->super_copy));
2336 ret = -EUCLEAN;
2337 goto out;
2338 }
2339
2340 if (btrfs_check_super_csum(fs_info, sb)) {
2341 btrfs_err(fs_info, "csum for on-disk super block no longer matches");
2342 ret = -EUCLEAN;
2343 goto out;
2344 }
2345
2346 /* Btrfs_validate_super() includes fsid check against super->fsid. */
2347 ret = btrfs_validate_super(fs_info, sb, 0);
2348 if (ret < 0)
2349 goto out;
2350
2351 last_trans = btrfs_get_last_trans_committed(fs_info);
2352 if (btrfs_super_generation(sb) != last_trans) {
2353 btrfs_err(fs_info, "transid mismatch, has %llu expect %llu",
2354 btrfs_super_generation(sb), last_trans);
2355 ret = -EUCLEAN;
2356 goto out;
2357 }
2358 out:
2359 btrfs_release_disk_super(sb);
2360 return ret;
2361 }
2362
btrfs_unfreeze(struct super_block * sb)2363 static int btrfs_unfreeze(struct super_block *sb)
2364 {
2365 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2366 struct btrfs_device *device;
2367 int ret = 0;
2368
2369 /*
2370 * Make sure the fs is not changed by accident (like hibernation then
2371 * modified by other OS).
2372 * If we found anything wrong, we mark the fs error immediately.
2373 *
2374 * And since the fs is frozen, no one can modify the fs yet, thus
2375 * we don't need to hold device_list_mutex.
2376 */
2377 list_for_each_entry(device, &fs_info->fs_devices->devices, dev_list) {
2378 ret = check_dev_super(device);
2379 if (ret < 0) {
2380 btrfs_handle_fs_error(fs_info, ret,
2381 "super block on devid %llu got modified unexpectedly",
2382 device->devid);
2383 break;
2384 }
2385 }
2386 clear_bit(BTRFS_FS_FROZEN, &fs_info->flags);
2387
2388 /*
2389 * We still return 0, to allow VFS layer to unfreeze the fs even the
2390 * above checks failed. Since the fs is either fine or read-only, we're
2391 * safe to continue, without causing further damage.
2392 */
2393 return 0;
2394 }
2395
btrfs_show_devname(struct seq_file * m,struct dentry * root)2396 static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
2397 {
2398 struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
2399
2400 /*
2401 * There should be always a valid pointer in latest_dev, it may be stale
2402 * for a short moment in case it's being deleted but still valid until
2403 * the end of RCU grace period.
2404 */
2405 rcu_read_lock();
2406 seq_escape(m, btrfs_dev_name(fs_info->fs_devices->latest_dev), " \t\n\\");
2407 rcu_read_unlock();
2408
2409 return 0;
2410 }
2411
btrfs_nr_cached_objects(struct super_block * sb,struct shrink_control * sc)2412 static long btrfs_nr_cached_objects(struct super_block *sb, struct shrink_control *sc)
2413 {
2414 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2415 const s64 nr = percpu_counter_sum_positive(&fs_info->evictable_extent_maps);
2416
2417 trace_btrfs_extent_map_shrinker_count(fs_info, nr);
2418
2419 return nr;
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 btrfs_free_extent_maps(fs_info, nr_to_scan);
2428
2429 /* The extent map shrinker runs asynchronously, so always return 0. */
2430 return 0;
2431 }
2432
2433 static const struct super_operations btrfs_super_ops = {
2434 .drop_inode = btrfs_drop_inode,
2435 .evict_inode = btrfs_evict_inode,
2436 .put_super = btrfs_put_super,
2437 .sync_fs = btrfs_sync_fs,
2438 .show_options = btrfs_show_options,
2439 .show_devname = btrfs_show_devname,
2440 .alloc_inode = btrfs_alloc_inode,
2441 .destroy_inode = btrfs_destroy_inode,
2442 .free_inode = btrfs_free_inode,
2443 .statfs = btrfs_statfs,
2444 .freeze_fs = btrfs_freeze,
2445 .unfreeze_fs = btrfs_unfreeze,
2446 .nr_cached_objects = btrfs_nr_cached_objects,
2447 .free_cached_objects = btrfs_free_cached_objects,
2448 };
2449
2450 static const struct file_operations btrfs_ctl_fops = {
2451 .open = btrfs_control_open,
2452 .unlocked_ioctl = btrfs_control_ioctl,
2453 .compat_ioctl = compat_ptr_ioctl,
2454 .owner = THIS_MODULE,
2455 .llseek = noop_llseek,
2456 };
2457
2458 static struct miscdevice btrfs_misc = {
2459 .minor = BTRFS_MINOR,
2460 .name = "btrfs-control",
2461 .fops = &btrfs_ctl_fops
2462 };
2463
2464 MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
2465 MODULE_ALIAS("devname:btrfs-control");
2466
btrfs_interface_init(void)2467 static int __init btrfs_interface_init(void)
2468 {
2469 return misc_register(&btrfs_misc);
2470 }
2471
btrfs_interface_exit(void)2472 static __cold void btrfs_interface_exit(void)
2473 {
2474 misc_deregister(&btrfs_misc);
2475 }
2476
btrfs_print_mod_info(void)2477 static int __init btrfs_print_mod_info(void)
2478 {
2479 static const char options[] = ""
2480 #ifdef CONFIG_BTRFS_EXPERIMENTAL
2481 ", experimental=on"
2482 #endif
2483 #ifdef CONFIG_BTRFS_DEBUG
2484 ", debug=on"
2485 #endif
2486 #ifdef CONFIG_BTRFS_ASSERT
2487 ", assert=on"
2488 #endif
2489 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
2490 ", ref-verify=on"
2491 #endif
2492 #ifdef CONFIG_BLK_DEV_ZONED
2493 ", zoned=yes"
2494 #else
2495 ", zoned=no"
2496 #endif
2497 #ifdef CONFIG_FS_VERITY
2498 ", fsverity=yes"
2499 #else
2500 ", fsverity=no"
2501 #endif
2502 ;
2503
2504 #ifdef CONFIG_BTRFS_EXPERIMENTAL
2505 if (btrfs_get_mod_read_policy() == NULL)
2506 pr_info("Btrfs loaded%s\n", options);
2507 else
2508 pr_info("Btrfs loaded%s, read_policy=%s\n",
2509 options, btrfs_get_mod_read_policy());
2510 #else
2511 pr_info("Btrfs loaded%s\n", options);
2512 #endif
2513
2514 return 0;
2515 }
2516
register_btrfs(void)2517 static int register_btrfs(void)
2518 {
2519 return register_filesystem(&btrfs_fs_type);
2520 }
2521
unregister_btrfs(void)2522 static void unregister_btrfs(void)
2523 {
2524 unregister_filesystem(&btrfs_fs_type);
2525 }
2526
2527 /* Helper structure for long init/exit functions. */
2528 struct init_sequence {
2529 int (*init_func)(void);
2530 /* Can be NULL if the init_func doesn't need cleanup. */
2531 void (*exit_func)(void);
2532 };
2533
2534 static const struct init_sequence mod_init_seq[] = {
2535 {
2536 .init_func = btrfs_props_init,
2537 .exit_func = NULL,
2538 }, {
2539 .init_func = btrfs_init_sysfs,
2540 .exit_func = btrfs_exit_sysfs,
2541 }, {
2542 .init_func = btrfs_init_compress,
2543 .exit_func = btrfs_exit_compress,
2544 }, {
2545 .init_func = btrfs_init_cachep,
2546 .exit_func = btrfs_destroy_cachep,
2547 }, {
2548 .init_func = btrfs_init_dio,
2549 .exit_func = btrfs_destroy_dio,
2550 }, {
2551 .init_func = btrfs_transaction_init,
2552 .exit_func = btrfs_transaction_exit,
2553 }, {
2554 .init_func = btrfs_ctree_init,
2555 .exit_func = btrfs_ctree_exit,
2556 }, {
2557 .init_func = btrfs_free_space_init,
2558 .exit_func = btrfs_free_space_exit,
2559 }, {
2560 .init_func = btrfs_extent_state_init_cachep,
2561 .exit_func = btrfs_extent_state_free_cachep,
2562 }, {
2563 .init_func = extent_buffer_init_cachep,
2564 .exit_func = extent_buffer_free_cachep,
2565 }, {
2566 .init_func = btrfs_bioset_init,
2567 .exit_func = btrfs_bioset_exit,
2568 }, {
2569 .init_func = btrfs_extent_map_init,
2570 .exit_func = btrfs_extent_map_exit,
2571 #ifdef CONFIG_BTRFS_EXPERIMENTAL
2572 }, {
2573 .init_func = btrfs_read_policy_init,
2574 .exit_func = NULL,
2575 #endif
2576 }, {
2577 .init_func = ordered_data_init,
2578 .exit_func = ordered_data_exit,
2579 }, {
2580 .init_func = btrfs_delayed_inode_init,
2581 .exit_func = btrfs_delayed_inode_exit,
2582 }, {
2583 .init_func = btrfs_auto_defrag_init,
2584 .exit_func = btrfs_auto_defrag_exit,
2585 }, {
2586 .init_func = btrfs_delayed_ref_init,
2587 .exit_func = btrfs_delayed_ref_exit,
2588 }, {
2589 .init_func = btrfs_prelim_ref_init,
2590 .exit_func = btrfs_prelim_ref_exit,
2591 }, {
2592 .init_func = btrfs_interface_init,
2593 .exit_func = btrfs_interface_exit,
2594 }, {
2595 .init_func = btrfs_print_mod_info,
2596 .exit_func = NULL,
2597 }, {
2598 .init_func = btrfs_run_sanity_tests,
2599 .exit_func = NULL,
2600 }, {
2601 .init_func = register_btrfs,
2602 .exit_func = unregister_btrfs,
2603 }
2604 };
2605
2606 static bool mod_init_result[ARRAY_SIZE(mod_init_seq)];
2607
btrfs_exit_btrfs_fs(void)2608 static __always_inline void btrfs_exit_btrfs_fs(void)
2609 {
2610 int i;
2611
2612 for (i = ARRAY_SIZE(mod_init_seq) - 1; i >= 0; i--) {
2613 if (!mod_init_result[i])
2614 continue;
2615 if (mod_init_seq[i].exit_func)
2616 mod_init_seq[i].exit_func();
2617 mod_init_result[i] = false;
2618 }
2619 }
2620
exit_btrfs_fs(void)2621 static void __exit exit_btrfs_fs(void)
2622 {
2623 btrfs_exit_btrfs_fs();
2624 btrfs_cleanup_fs_uuids();
2625 }
2626
init_btrfs_fs(void)2627 static int __init init_btrfs_fs(void)
2628 {
2629 int ret;
2630 int i;
2631
2632 for (i = 0; i < ARRAY_SIZE(mod_init_seq); i++) {
2633 ASSERT(!mod_init_result[i]);
2634 ret = mod_init_seq[i].init_func();
2635 if (ret < 0) {
2636 btrfs_exit_btrfs_fs();
2637 return ret;
2638 }
2639 mod_init_result[i] = true;
2640 }
2641 return 0;
2642 }
2643
2644 late_initcall(init_btrfs_fs);
2645 module_exit(exit_btrfs_fs)
2646
2647 MODULE_DESCRIPTION("B-Tree File System (BTRFS)");
2648 MODULE_LICENSE("GPL");
2649 MODULE_SOFTDEP("pre: crc32c");
2650 MODULE_SOFTDEP("pre: xxhash64");
2651 MODULE_SOFTDEP("pre: sha256");
2652 MODULE_SOFTDEP("pre: blake2b-256");
2653