xref: /openbmc/linux/fs/btrfs/super.c (revision c2a311dc)
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 "messages.h"
30 #include "delayed-inode.h"
31 #include "ctree.h"
32 #include "disk-io.h"
33 #include "transaction.h"
34 #include "btrfs_inode.h"
35 #include "print-tree.h"
36 #include "props.h"
37 #include "xattr.h"
38 #include "bio.h"
39 #include "export.h"
40 #include "compression.h"
41 #include "rcu-string.h"
42 #include "dev-replace.h"
43 #include "free-space-cache.h"
44 #include "backref.h"
45 #include "space-info.h"
46 #include "sysfs.h"
47 #include "zoned.h"
48 #include "tests/btrfs-tests.h"
49 #include "block-group.h"
50 #include "discard.h"
51 #include "qgroup.h"
52 #include "raid56.h"
53 #include "fs.h"
54 #include "accessors.h"
55 #include "defrag.h"
56 #include "dir-item.h"
57 #include "ioctl.h"
58 #include "scrub.h"
59 #include "verity.h"
60 #include "super.h"
61 #include "extent-tree.h"
62 #define CREATE_TRACE_POINTS
63 #include <trace/events/btrfs.h>
64 
65 static const struct super_operations btrfs_super_ops;
66 
67 /*
68  * Types for mounting the default subvolume and a subvolume explicitly
69  * requested by subvol=/path. That way the callchain is straightforward and we
70  * don't have to play tricks with the mount options and recursive calls to
71  * btrfs_mount.
72  *
73  * The new btrfs_root_fs_type also servers as a tag for the bdev_holder.
74  */
75 static struct file_system_type btrfs_fs_type;
76 static struct file_system_type btrfs_root_fs_type;
77 
78 static int btrfs_remount(struct super_block *sb, int *flags, char *data);
79 
80 static void btrfs_put_super(struct super_block *sb)
81 {
82 	close_ctree(btrfs_sb(sb));
83 }
84 
85 enum {
86 	Opt_acl, Opt_noacl,
87 	Opt_clear_cache,
88 	Opt_commit_interval,
89 	Opt_compress,
90 	Opt_compress_force,
91 	Opt_compress_force_type,
92 	Opt_compress_type,
93 	Opt_degraded,
94 	Opt_device,
95 	Opt_fatal_errors,
96 	Opt_flushoncommit, Opt_noflushoncommit,
97 	Opt_max_inline,
98 	Opt_barrier, Opt_nobarrier,
99 	Opt_datacow, Opt_nodatacow,
100 	Opt_datasum, Opt_nodatasum,
101 	Opt_defrag, Opt_nodefrag,
102 	Opt_discard, Opt_nodiscard,
103 	Opt_discard_mode,
104 	Opt_norecovery,
105 	Opt_ratio,
106 	Opt_rescan_uuid_tree,
107 	Opt_skip_balance,
108 	Opt_space_cache, Opt_no_space_cache,
109 	Opt_space_cache_version,
110 	Opt_ssd, Opt_nossd,
111 	Opt_ssd_spread, Opt_nossd_spread,
112 	Opt_subvol,
113 	Opt_subvol_empty,
114 	Opt_subvolid,
115 	Opt_thread_pool,
116 	Opt_treelog, Opt_notreelog,
117 	Opt_user_subvol_rm_allowed,
118 
119 	/* Rescue options */
120 	Opt_rescue,
121 	Opt_usebackuproot,
122 	Opt_nologreplay,
123 	Opt_ignorebadroots,
124 	Opt_ignoredatacsums,
125 	Opt_rescue_all,
126 
127 	/* Deprecated options */
128 	Opt_recovery,
129 	Opt_inode_cache, Opt_noinode_cache,
130 
131 	/* Debugging options */
132 	Opt_check_integrity,
133 	Opt_check_integrity_including_extent_data,
134 	Opt_check_integrity_print_mask,
135 	Opt_enospc_debug, Opt_noenospc_debug,
136 #ifdef CONFIG_BTRFS_DEBUG
137 	Opt_fragment_data, Opt_fragment_metadata, Opt_fragment_all,
138 #endif
139 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
140 	Opt_ref_verify,
141 #endif
142 	Opt_err,
143 };
144 
145 static const match_table_t tokens = {
146 	{Opt_acl, "acl"},
147 	{Opt_noacl, "noacl"},
148 	{Opt_clear_cache, "clear_cache"},
149 	{Opt_commit_interval, "commit=%u"},
150 	{Opt_compress, "compress"},
151 	{Opt_compress_type, "compress=%s"},
152 	{Opt_compress_force, "compress-force"},
153 	{Opt_compress_force_type, "compress-force=%s"},
154 	{Opt_degraded, "degraded"},
155 	{Opt_device, "device=%s"},
156 	{Opt_fatal_errors, "fatal_errors=%s"},
157 	{Opt_flushoncommit, "flushoncommit"},
158 	{Opt_noflushoncommit, "noflushoncommit"},
159 	{Opt_inode_cache, "inode_cache"},
160 	{Opt_noinode_cache, "noinode_cache"},
161 	{Opt_max_inline, "max_inline=%s"},
162 	{Opt_barrier, "barrier"},
163 	{Opt_nobarrier, "nobarrier"},
164 	{Opt_datacow, "datacow"},
165 	{Opt_nodatacow, "nodatacow"},
166 	{Opt_datasum, "datasum"},
167 	{Opt_nodatasum, "nodatasum"},
168 	{Opt_defrag, "autodefrag"},
169 	{Opt_nodefrag, "noautodefrag"},
170 	{Opt_discard, "discard"},
171 	{Opt_discard_mode, "discard=%s"},
172 	{Opt_nodiscard, "nodiscard"},
173 	{Opt_norecovery, "norecovery"},
174 	{Opt_ratio, "metadata_ratio=%u"},
175 	{Opt_rescan_uuid_tree, "rescan_uuid_tree"},
176 	{Opt_skip_balance, "skip_balance"},
177 	{Opt_space_cache, "space_cache"},
178 	{Opt_no_space_cache, "nospace_cache"},
179 	{Opt_space_cache_version, "space_cache=%s"},
180 	{Opt_ssd, "ssd"},
181 	{Opt_nossd, "nossd"},
182 	{Opt_ssd_spread, "ssd_spread"},
183 	{Opt_nossd_spread, "nossd_spread"},
184 	{Opt_subvol, "subvol=%s"},
185 	{Opt_subvol_empty, "subvol="},
186 	{Opt_subvolid, "subvolid=%s"},
187 	{Opt_thread_pool, "thread_pool=%u"},
188 	{Opt_treelog, "treelog"},
189 	{Opt_notreelog, "notreelog"},
190 	{Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
191 
192 	/* Rescue options */
193 	{Opt_rescue, "rescue=%s"},
194 	/* Deprecated, with alias rescue=nologreplay */
195 	{Opt_nologreplay, "nologreplay"},
196 	/* Deprecated, with alias rescue=usebackuproot */
197 	{Opt_usebackuproot, "usebackuproot"},
198 
199 	/* Deprecated options */
200 	{Opt_recovery, "recovery"},
201 
202 	/* Debugging options */
203 	{Opt_check_integrity, "check_int"},
204 	{Opt_check_integrity_including_extent_data, "check_int_data"},
205 	{Opt_check_integrity_print_mask, "check_int_print_mask=%u"},
206 	{Opt_enospc_debug, "enospc_debug"},
207 	{Opt_noenospc_debug, "noenospc_debug"},
208 #ifdef CONFIG_BTRFS_DEBUG
209 	{Opt_fragment_data, "fragment=data"},
210 	{Opt_fragment_metadata, "fragment=metadata"},
211 	{Opt_fragment_all, "fragment=all"},
212 #endif
213 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
214 	{Opt_ref_verify, "ref_verify"},
215 #endif
216 	{Opt_err, NULL},
217 };
218 
219 static const match_table_t rescue_tokens = {
220 	{Opt_usebackuproot, "usebackuproot"},
221 	{Opt_nologreplay, "nologreplay"},
222 	{Opt_ignorebadroots, "ignorebadroots"},
223 	{Opt_ignorebadroots, "ibadroots"},
224 	{Opt_ignoredatacsums, "ignoredatacsums"},
225 	{Opt_ignoredatacsums, "idatacsums"},
226 	{Opt_rescue_all, "all"},
227 	{Opt_err, NULL},
228 };
229 
230 static bool check_ro_option(struct btrfs_fs_info *fs_info, unsigned long opt,
231 			    const char *opt_name)
232 {
233 	if (fs_info->mount_opt & opt) {
234 		btrfs_err(fs_info, "%s must be used with ro mount option",
235 			  opt_name);
236 		return true;
237 	}
238 	return false;
239 }
240 
241 static int parse_rescue_options(struct btrfs_fs_info *info, const char *options)
242 {
243 	char *opts;
244 	char *orig;
245 	char *p;
246 	substring_t args[MAX_OPT_ARGS];
247 	int ret = 0;
248 
249 	opts = kstrdup(options, GFP_KERNEL);
250 	if (!opts)
251 		return -ENOMEM;
252 	orig = opts;
253 
254 	while ((p = strsep(&opts, ":")) != NULL) {
255 		int token;
256 
257 		if (!*p)
258 			continue;
259 		token = match_token(p, rescue_tokens, args);
260 		switch (token){
261 		case Opt_usebackuproot:
262 			btrfs_info(info,
263 				   "trying to use backup root at mount time");
264 			btrfs_set_opt(info->mount_opt, USEBACKUPROOT);
265 			break;
266 		case Opt_nologreplay:
267 			btrfs_set_and_info(info, NOLOGREPLAY,
268 					   "disabling log replay at mount time");
269 			break;
270 		case Opt_ignorebadroots:
271 			btrfs_set_and_info(info, IGNOREBADROOTS,
272 					   "ignoring bad roots");
273 			break;
274 		case Opt_ignoredatacsums:
275 			btrfs_set_and_info(info, IGNOREDATACSUMS,
276 					   "ignoring data csums");
277 			break;
278 		case Opt_rescue_all:
279 			btrfs_info(info, "enabling all of the rescue options");
280 			btrfs_set_and_info(info, IGNOREDATACSUMS,
281 					   "ignoring data csums");
282 			btrfs_set_and_info(info, IGNOREBADROOTS,
283 					   "ignoring bad roots");
284 			btrfs_set_and_info(info, NOLOGREPLAY,
285 					   "disabling log replay at mount time");
286 			break;
287 		case Opt_err:
288 			btrfs_info(info, "unrecognized rescue option '%s'", p);
289 			ret = -EINVAL;
290 			goto out;
291 		default:
292 			break;
293 		}
294 
295 	}
296 out:
297 	kfree(orig);
298 	return ret;
299 }
300 
301 /*
302  * Regular mount options parser.  Everything that is needed only when
303  * reading in a new superblock is parsed here.
304  * XXX JDM: This needs to be cleaned up for remount.
305  */
306 int btrfs_parse_options(struct btrfs_fs_info *info, char *options,
307 			unsigned long new_flags)
308 {
309 	substring_t args[MAX_OPT_ARGS];
310 	char *p, *num;
311 	int intarg;
312 	int ret = 0;
313 	char *compress_type;
314 	bool compress_force = false;
315 	enum btrfs_compression_type saved_compress_type;
316 	int saved_compress_level;
317 	bool saved_compress_force;
318 	int no_compress = 0;
319 	const bool remounting = test_bit(BTRFS_FS_STATE_REMOUNTING, &info->fs_state);
320 
321 	if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE))
322 		btrfs_set_opt(info->mount_opt, FREE_SPACE_TREE);
323 	else if (btrfs_free_space_cache_v1_active(info)) {
324 		if (btrfs_is_zoned(info)) {
325 			btrfs_info(info,
326 			"zoned: clearing existing space cache");
327 			btrfs_set_super_cache_generation(info->super_copy, 0);
328 		} else {
329 			btrfs_set_opt(info->mount_opt, SPACE_CACHE);
330 		}
331 	}
332 
333 	/*
334 	 * Even the options are empty, we still need to do extra check
335 	 * against new flags
336 	 */
337 	if (!options)
338 		goto check;
339 
340 	while ((p = strsep(&options, ",")) != NULL) {
341 		int token;
342 		if (!*p)
343 			continue;
344 
345 		token = match_token(p, tokens, args);
346 		switch (token) {
347 		case Opt_degraded:
348 			btrfs_info(info, "allowing degraded mounts");
349 			btrfs_set_opt(info->mount_opt, DEGRADED);
350 			break;
351 		case Opt_subvol:
352 		case Opt_subvol_empty:
353 		case Opt_subvolid:
354 		case Opt_device:
355 			/*
356 			 * These are parsed by btrfs_parse_subvol_options or
357 			 * btrfs_parse_device_options and can be ignored here.
358 			 */
359 			break;
360 		case Opt_nodatasum:
361 			btrfs_set_and_info(info, NODATASUM,
362 					   "setting nodatasum");
363 			break;
364 		case Opt_datasum:
365 			if (btrfs_test_opt(info, NODATASUM)) {
366 				if (btrfs_test_opt(info, NODATACOW))
367 					btrfs_info(info,
368 						   "setting datasum, datacow enabled");
369 				else
370 					btrfs_info(info, "setting datasum");
371 			}
372 			btrfs_clear_opt(info->mount_opt, NODATACOW);
373 			btrfs_clear_opt(info->mount_opt, NODATASUM);
374 			break;
375 		case Opt_nodatacow:
376 			if (!btrfs_test_opt(info, NODATACOW)) {
377 				if (!btrfs_test_opt(info, COMPRESS) ||
378 				    !btrfs_test_opt(info, FORCE_COMPRESS)) {
379 					btrfs_info(info,
380 						   "setting nodatacow, compression disabled");
381 				} else {
382 					btrfs_info(info, "setting nodatacow");
383 				}
384 			}
385 			btrfs_clear_opt(info->mount_opt, COMPRESS);
386 			btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
387 			btrfs_set_opt(info->mount_opt, NODATACOW);
388 			btrfs_set_opt(info->mount_opt, NODATASUM);
389 			break;
390 		case Opt_datacow:
391 			btrfs_clear_and_info(info, NODATACOW,
392 					     "setting datacow");
393 			break;
394 		case Opt_compress_force:
395 		case Opt_compress_force_type:
396 			compress_force = true;
397 			fallthrough;
398 		case Opt_compress:
399 		case Opt_compress_type:
400 			saved_compress_type = btrfs_test_opt(info,
401 							     COMPRESS) ?
402 				info->compress_type : BTRFS_COMPRESS_NONE;
403 			saved_compress_force =
404 				btrfs_test_opt(info, FORCE_COMPRESS);
405 			saved_compress_level = info->compress_level;
406 			if (token == Opt_compress ||
407 			    token == Opt_compress_force ||
408 			    strncmp(args[0].from, "zlib", 4) == 0) {
409 				compress_type = "zlib";
410 
411 				info->compress_type = BTRFS_COMPRESS_ZLIB;
412 				info->compress_level = BTRFS_ZLIB_DEFAULT_LEVEL;
413 				/*
414 				 * args[0] contains uninitialized data since
415 				 * for these tokens we don't expect any
416 				 * parameter.
417 				 */
418 				if (token != Opt_compress &&
419 				    token != Opt_compress_force)
420 					info->compress_level =
421 					  btrfs_compress_str2level(
422 							BTRFS_COMPRESS_ZLIB,
423 							args[0].from + 4);
424 				btrfs_set_opt(info->mount_opt, COMPRESS);
425 				btrfs_clear_opt(info->mount_opt, NODATACOW);
426 				btrfs_clear_opt(info->mount_opt, NODATASUM);
427 				no_compress = 0;
428 			} else if (strncmp(args[0].from, "lzo", 3) == 0) {
429 				compress_type = "lzo";
430 				info->compress_type = BTRFS_COMPRESS_LZO;
431 				info->compress_level = 0;
432 				btrfs_set_opt(info->mount_opt, COMPRESS);
433 				btrfs_clear_opt(info->mount_opt, NODATACOW);
434 				btrfs_clear_opt(info->mount_opt, NODATASUM);
435 				btrfs_set_fs_incompat(info, COMPRESS_LZO);
436 				no_compress = 0;
437 			} else if (strncmp(args[0].from, "zstd", 4) == 0) {
438 				compress_type = "zstd";
439 				info->compress_type = BTRFS_COMPRESS_ZSTD;
440 				info->compress_level =
441 					btrfs_compress_str2level(
442 							 BTRFS_COMPRESS_ZSTD,
443 							 args[0].from + 4);
444 				btrfs_set_opt(info->mount_opt, COMPRESS);
445 				btrfs_clear_opt(info->mount_opt, NODATACOW);
446 				btrfs_clear_opt(info->mount_opt, NODATASUM);
447 				btrfs_set_fs_incompat(info, COMPRESS_ZSTD);
448 				no_compress = 0;
449 			} else if (strncmp(args[0].from, "no", 2) == 0) {
450 				compress_type = "no";
451 				info->compress_level = 0;
452 				info->compress_type = 0;
453 				btrfs_clear_opt(info->mount_opt, COMPRESS);
454 				btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
455 				compress_force = false;
456 				no_compress++;
457 			} else {
458 				btrfs_err(info, "unrecognized compression value %s",
459 					  args[0].from);
460 				ret = -EINVAL;
461 				goto out;
462 			}
463 
464 			if (compress_force) {
465 				btrfs_set_opt(info->mount_opt, FORCE_COMPRESS);
466 			} else {
467 				/*
468 				 * If we remount from compress-force=xxx to
469 				 * compress=xxx, we need clear FORCE_COMPRESS
470 				 * flag, otherwise, there is no way for users
471 				 * to disable forcible compression separately.
472 				 */
473 				btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
474 			}
475 			if (no_compress == 1) {
476 				btrfs_info(info, "use no compression");
477 			} else if ((info->compress_type != saved_compress_type) ||
478 				   (compress_force != saved_compress_force) ||
479 				   (info->compress_level != saved_compress_level)) {
480 				btrfs_info(info, "%s %s compression, level %d",
481 					   (compress_force) ? "force" : "use",
482 					   compress_type, info->compress_level);
483 			}
484 			compress_force = false;
485 			break;
486 		case Opt_ssd:
487 			btrfs_set_and_info(info, SSD,
488 					   "enabling ssd optimizations");
489 			btrfs_clear_opt(info->mount_opt, NOSSD);
490 			break;
491 		case Opt_ssd_spread:
492 			btrfs_set_and_info(info, SSD,
493 					   "enabling ssd optimizations");
494 			btrfs_set_and_info(info, SSD_SPREAD,
495 					   "using spread ssd allocation scheme");
496 			btrfs_clear_opt(info->mount_opt, NOSSD);
497 			break;
498 		case Opt_nossd:
499 			btrfs_set_opt(info->mount_opt, NOSSD);
500 			btrfs_clear_and_info(info, SSD,
501 					     "not using ssd optimizations");
502 			fallthrough;
503 		case Opt_nossd_spread:
504 			btrfs_clear_and_info(info, SSD_SPREAD,
505 					     "not using spread ssd allocation scheme");
506 			break;
507 		case Opt_barrier:
508 			btrfs_clear_and_info(info, NOBARRIER,
509 					     "turning on barriers");
510 			break;
511 		case Opt_nobarrier:
512 			btrfs_set_and_info(info, NOBARRIER,
513 					   "turning off barriers");
514 			break;
515 		case Opt_thread_pool:
516 			ret = match_int(&args[0], &intarg);
517 			if (ret) {
518 				btrfs_err(info, "unrecognized thread_pool value %s",
519 					  args[0].from);
520 				goto out;
521 			} else if (intarg == 0) {
522 				btrfs_err(info, "invalid value 0 for thread_pool");
523 				ret = -EINVAL;
524 				goto out;
525 			}
526 			info->thread_pool_size = intarg;
527 			break;
528 		case Opt_max_inline:
529 			num = match_strdup(&args[0]);
530 			if (num) {
531 				info->max_inline = memparse(num, NULL);
532 				kfree(num);
533 
534 				if (info->max_inline) {
535 					info->max_inline = min_t(u64,
536 						info->max_inline,
537 						info->sectorsize);
538 				}
539 				btrfs_info(info, "max_inline at %llu",
540 					   info->max_inline);
541 			} else {
542 				ret = -ENOMEM;
543 				goto out;
544 			}
545 			break;
546 		case Opt_acl:
547 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
548 			info->sb->s_flags |= SB_POSIXACL;
549 			break;
550 #else
551 			btrfs_err(info, "support for ACL not compiled in!");
552 			ret = -EINVAL;
553 			goto out;
554 #endif
555 		case Opt_noacl:
556 			info->sb->s_flags &= ~SB_POSIXACL;
557 			break;
558 		case Opt_notreelog:
559 			btrfs_set_and_info(info, NOTREELOG,
560 					   "disabling tree log");
561 			break;
562 		case Opt_treelog:
563 			btrfs_clear_and_info(info, NOTREELOG,
564 					     "enabling tree log");
565 			break;
566 		case Opt_norecovery:
567 		case Opt_nologreplay:
568 			btrfs_warn(info,
569 		"'nologreplay' is deprecated, use 'rescue=nologreplay' instead");
570 			btrfs_set_and_info(info, NOLOGREPLAY,
571 					   "disabling log replay at mount time");
572 			break;
573 		case Opt_flushoncommit:
574 			btrfs_set_and_info(info, FLUSHONCOMMIT,
575 					   "turning on flush-on-commit");
576 			break;
577 		case Opt_noflushoncommit:
578 			btrfs_clear_and_info(info, FLUSHONCOMMIT,
579 					     "turning off flush-on-commit");
580 			break;
581 		case Opt_ratio:
582 			ret = match_int(&args[0], &intarg);
583 			if (ret) {
584 				btrfs_err(info, "unrecognized metadata_ratio value %s",
585 					  args[0].from);
586 				goto out;
587 			}
588 			info->metadata_ratio = intarg;
589 			btrfs_info(info, "metadata ratio %u",
590 				   info->metadata_ratio);
591 			break;
592 		case Opt_discard:
593 		case Opt_discard_mode:
594 			if (token == Opt_discard ||
595 			    strcmp(args[0].from, "sync") == 0) {
596 				btrfs_clear_opt(info->mount_opt, DISCARD_ASYNC);
597 				btrfs_set_and_info(info, DISCARD_SYNC,
598 						   "turning on sync discard");
599 			} else if (strcmp(args[0].from, "async") == 0) {
600 				btrfs_clear_opt(info->mount_opt, DISCARD_SYNC);
601 				btrfs_set_and_info(info, DISCARD_ASYNC,
602 						   "turning on async discard");
603 			} else {
604 				btrfs_err(info, "unrecognized discard mode value %s",
605 					  args[0].from);
606 				ret = -EINVAL;
607 				goto out;
608 			}
609 			btrfs_clear_opt(info->mount_opt, NODISCARD);
610 			break;
611 		case Opt_nodiscard:
612 			btrfs_clear_and_info(info, DISCARD_SYNC,
613 					     "turning off discard");
614 			btrfs_clear_and_info(info, DISCARD_ASYNC,
615 					     "turning off async discard");
616 			btrfs_set_opt(info->mount_opt, NODISCARD);
617 			break;
618 		case Opt_space_cache:
619 		case Opt_space_cache_version:
620 			/*
621 			 * We already set FREE_SPACE_TREE above because we have
622 			 * compat_ro(FREE_SPACE_TREE) set, and we aren't going
623 			 * to allow v1 to be set for extent tree v2, simply
624 			 * ignore this setting if we're extent tree v2.
625 			 */
626 			if (btrfs_fs_incompat(info, EXTENT_TREE_V2))
627 				break;
628 			if (token == Opt_space_cache ||
629 			    strcmp(args[0].from, "v1") == 0) {
630 				btrfs_clear_opt(info->mount_opt,
631 						FREE_SPACE_TREE);
632 				btrfs_set_and_info(info, SPACE_CACHE,
633 					   "enabling disk space caching");
634 			} else if (strcmp(args[0].from, "v2") == 0) {
635 				btrfs_clear_opt(info->mount_opt,
636 						SPACE_CACHE);
637 				btrfs_set_and_info(info, FREE_SPACE_TREE,
638 						   "enabling free space tree");
639 			} else {
640 				btrfs_err(info, "unrecognized space_cache value %s",
641 					  args[0].from);
642 				ret = -EINVAL;
643 				goto out;
644 			}
645 			break;
646 		case Opt_rescan_uuid_tree:
647 			btrfs_set_opt(info->mount_opt, RESCAN_UUID_TREE);
648 			break;
649 		case Opt_no_space_cache:
650 			/*
651 			 * We cannot operate without the free space tree with
652 			 * extent tree v2, ignore this option.
653 			 */
654 			if (btrfs_fs_incompat(info, EXTENT_TREE_V2))
655 				break;
656 			if (btrfs_test_opt(info, SPACE_CACHE)) {
657 				btrfs_clear_and_info(info, SPACE_CACHE,
658 					     "disabling disk space caching");
659 			}
660 			if (btrfs_test_opt(info, FREE_SPACE_TREE)) {
661 				btrfs_clear_and_info(info, FREE_SPACE_TREE,
662 					     "disabling free space tree");
663 			}
664 			break;
665 		case Opt_inode_cache:
666 		case Opt_noinode_cache:
667 			btrfs_warn(info,
668 	"the 'inode_cache' option is deprecated and has no effect since 5.11");
669 			break;
670 		case Opt_clear_cache:
671 			/*
672 			 * We cannot clear the free space tree with extent tree
673 			 * v2, ignore this option.
674 			 */
675 			if (btrfs_fs_incompat(info, EXTENT_TREE_V2))
676 				break;
677 			btrfs_set_and_info(info, CLEAR_CACHE,
678 					   "force clearing of disk cache");
679 			break;
680 		case Opt_user_subvol_rm_allowed:
681 			btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
682 			break;
683 		case Opt_enospc_debug:
684 			btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
685 			break;
686 		case Opt_noenospc_debug:
687 			btrfs_clear_opt(info->mount_opt, ENOSPC_DEBUG);
688 			break;
689 		case Opt_defrag:
690 			btrfs_set_and_info(info, AUTO_DEFRAG,
691 					   "enabling auto defrag");
692 			break;
693 		case Opt_nodefrag:
694 			btrfs_clear_and_info(info, AUTO_DEFRAG,
695 					     "disabling auto defrag");
696 			break;
697 		case Opt_recovery:
698 		case Opt_usebackuproot:
699 			btrfs_warn(info,
700 			"'%s' is deprecated, use 'rescue=usebackuproot' instead",
701 				   token == Opt_recovery ? "recovery" :
702 				   "usebackuproot");
703 			btrfs_info(info,
704 				   "trying to use backup root at mount time");
705 			btrfs_set_opt(info->mount_opt, USEBACKUPROOT);
706 			break;
707 		case Opt_skip_balance:
708 			btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
709 			break;
710 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
711 		case Opt_check_integrity_including_extent_data:
712 			btrfs_warn(info,
713 	"integrity checker is deprecated and will be removed in 6.7");
714 			btrfs_info(info,
715 				   "enabling check integrity including extent data");
716 			btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY_DATA);
717 			btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
718 			break;
719 		case Opt_check_integrity:
720 			btrfs_warn(info,
721 	"integrity checker is deprecated and will be removed in 6.7");
722 			btrfs_info(info, "enabling check integrity");
723 			btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
724 			break;
725 		case Opt_check_integrity_print_mask:
726 			ret = match_int(&args[0], &intarg);
727 			if (ret) {
728 				btrfs_err(info,
729 				"unrecognized check_integrity_print_mask value %s",
730 					args[0].from);
731 				goto out;
732 			}
733 			info->check_integrity_print_mask = intarg;
734 			btrfs_warn(info,
735 	"integrity checker is deprecated and will be removed in 6.7");
736 			btrfs_info(info, "check_integrity_print_mask 0x%x",
737 				   info->check_integrity_print_mask);
738 			break;
739 #else
740 		case Opt_check_integrity_including_extent_data:
741 		case Opt_check_integrity:
742 		case Opt_check_integrity_print_mask:
743 			btrfs_err(info,
744 				  "support for check_integrity* not compiled in!");
745 			ret = -EINVAL;
746 			goto out;
747 #endif
748 		case Opt_fatal_errors:
749 			if (strcmp(args[0].from, "panic") == 0) {
750 				btrfs_set_opt(info->mount_opt,
751 					      PANIC_ON_FATAL_ERROR);
752 			} else if (strcmp(args[0].from, "bug") == 0) {
753 				btrfs_clear_opt(info->mount_opt,
754 					      PANIC_ON_FATAL_ERROR);
755 			} else {
756 				btrfs_err(info, "unrecognized fatal_errors value %s",
757 					  args[0].from);
758 				ret = -EINVAL;
759 				goto out;
760 			}
761 			break;
762 		case Opt_commit_interval:
763 			intarg = 0;
764 			ret = match_int(&args[0], &intarg);
765 			if (ret) {
766 				btrfs_err(info, "unrecognized commit_interval value %s",
767 					  args[0].from);
768 				ret = -EINVAL;
769 				goto out;
770 			}
771 			if (intarg == 0) {
772 				btrfs_info(info,
773 					   "using default commit interval %us",
774 					   BTRFS_DEFAULT_COMMIT_INTERVAL);
775 				intarg = BTRFS_DEFAULT_COMMIT_INTERVAL;
776 			} else if (intarg > 300) {
777 				btrfs_warn(info, "excessive commit interval %d",
778 					   intarg);
779 			}
780 			info->commit_interval = intarg;
781 			break;
782 		case Opt_rescue:
783 			ret = parse_rescue_options(info, args[0].from);
784 			if (ret < 0) {
785 				btrfs_err(info, "unrecognized rescue value %s",
786 					  args[0].from);
787 				goto out;
788 			}
789 			break;
790 #ifdef CONFIG_BTRFS_DEBUG
791 		case Opt_fragment_all:
792 			btrfs_info(info, "fragmenting all space");
793 			btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
794 			btrfs_set_opt(info->mount_opt, FRAGMENT_METADATA);
795 			break;
796 		case Opt_fragment_metadata:
797 			btrfs_info(info, "fragmenting metadata");
798 			btrfs_set_opt(info->mount_opt,
799 				      FRAGMENT_METADATA);
800 			break;
801 		case Opt_fragment_data:
802 			btrfs_info(info, "fragmenting data");
803 			btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
804 			break;
805 #endif
806 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
807 		case Opt_ref_verify:
808 			btrfs_info(info, "doing ref verification");
809 			btrfs_set_opt(info->mount_opt, REF_VERIFY);
810 			break;
811 #endif
812 		case Opt_err:
813 			btrfs_err(info, "unrecognized mount option '%s'", p);
814 			ret = -EINVAL;
815 			goto out;
816 		default:
817 			break;
818 		}
819 	}
820 check:
821 	/* We're read-only, don't have to check. */
822 	if (new_flags & SB_RDONLY)
823 		goto out;
824 
825 	if (check_ro_option(info, BTRFS_MOUNT_NOLOGREPLAY, "nologreplay") ||
826 	    check_ro_option(info, BTRFS_MOUNT_IGNOREBADROOTS, "ignorebadroots") ||
827 	    check_ro_option(info, BTRFS_MOUNT_IGNOREDATACSUMS, "ignoredatacsums"))
828 		ret = -EINVAL;
829 out:
830 	if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE) &&
831 	    !btrfs_test_opt(info, FREE_SPACE_TREE) &&
832 	    !btrfs_test_opt(info, CLEAR_CACHE)) {
833 		btrfs_err(info, "cannot disable free space tree");
834 		ret = -EINVAL;
835 	}
836 	if (btrfs_fs_compat_ro(info, BLOCK_GROUP_TREE) &&
837 	     !btrfs_test_opt(info, FREE_SPACE_TREE)) {
838 		btrfs_err(info, "cannot disable free space tree with block-group-tree feature");
839 		ret = -EINVAL;
840 	}
841 	if (!ret)
842 		ret = btrfs_check_mountopts_zoned(info);
843 	if (!ret && !remounting) {
844 		if (btrfs_test_opt(info, SPACE_CACHE))
845 			btrfs_info(info, "disk space caching is enabled");
846 		if (btrfs_test_opt(info, FREE_SPACE_TREE))
847 			btrfs_info(info, "using free space tree");
848 	}
849 	return ret;
850 }
851 
852 /*
853  * Parse mount options that are required early in the mount process.
854  *
855  * All other options will be parsed on much later in the mount process and
856  * only when we need to allocate a new super block.
857  */
858 static int btrfs_parse_device_options(const char *options, blk_mode_t flags)
859 {
860 	substring_t args[MAX_OPT_ARGS];
861 	char *device_name, *opts, *orig, *p;
862 	struct btrfs_device *device = NULL;
863 	int error = 0;
864 
865 	lockdep_assert_held(&uuid_mutex);
866 
867 	if (!options)
868 		return 0;
869 
870 	/*
871 	 * strsep changes the string, duplicate it because btrfs_parse_options
872 	 * gets called later
873 	 */
874 	opts = kstrdup(options, GFP_KERNEL);
875 	if (!opts)
876 		return -ENOMEM;
877 	orig = opts;
878 
879 	while ((p = strsep(&opts, ",")) != NULL) {
880 		int token;
881 
882 		if (!*p)
883 			continue;
884 
885 		token = match_token(p, tokens, args);
886 		if (token == Opt_device) {
887 			device_name = match_strdup(&args[0]);
888 			if (!device_name) {
889 				error = -ENOMEM;
890 				goto out;
891 			}
892 			device = btrfs_scan_one_device(device_name, flags);
893 			kfree(device_name);
894 			if (IS_ERR(device)) {
895 				error = PTR_ERR(device);
896 				goto out;
897 			}
898 		}
899 	}
900 
901 out:
902 	kfree(orig);
903 	return error;
904 }
905 
906 /*
907  * Parse mount options that are related to subvolume id
908  *
909  * The value is later passed to mount_subvol()
910  */
911 static int btrfs_parse_subvol_options(const char *options, char **subvol_name,
912 		u64 *subvol_objectid)
913 {
914 	substring_t args[MAX_OPT_ARGS];
915 	char *opts, *orig, *p;
916 	int error = 0;
917 	u64 subvolid;
918 
919 	if (!options)
920 		return 0;
921 
922 	/*
923 	 * strsep changes the string, duplicate it because
924 	 * btrfs_parse_device_options gets called later
925 	 */
926 	opts = kstrdup(options, GFP_KERNEL);
927 	if (!opts)
928 		return -ENOMEM;
929 	orig = opts;
930 
931 	while ((p = strsep(&opts, ",")) != NULL) {
932 		int token;
933 		if (!*p)
934 			continue;
935 
936 		token = match_token(p, tokens, args);
937 		switch (token) {
938 		case Opt_subvol:
939 			kfree(*subvol_name);
940 			*subvol_name = match_strdup(&args[0]);
941 			if (!*subvol_name) {
942 				error = -ENOMEM;
943 				goto out;
944 			}
945 			break;
946 		case Opt_subvolid:
947 			error = match_u64(&args[0], &subvolid);
948 			if (error)
949 				goto out;
950 
951 			/* we want the original fs_tree */
952 			if (subvolid == 0)
953 				subvolid = BTRFS_FS_TREE_OBJECTID;
954 
955 			*subvol_objectid = subvolid;
956 			break;
957 		default:
958 			break;
959 		}
960 	}
961 
962 out:
963 	kfree(orig);
964 	return error;
965 }
966 
967 char *btrfs_get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
968 					  u64 subvol_objectid)
969 {
970 	struct btrfs_root *root = fs_info->tree_root;
971 	struct btrfs_root *fs_root = NULL;
972 	struct btrfs_root_ref *root_ref;
973 	struct btrfs_inode_ref *inode_ref;
974 	struct btrfs_key key;
975 	struct btrfs_path *path = NULL;
976 	char *name = NULL, *ptr;
977 	u64 dirid;
978 	int len;
979 	int ret;
980 
981 	path = btrfs_alloc_path();
982 	if (!path) {
983 		ret = -ENOMEM;
984 		goto err;
985 	}
986 
987 	name = kmalloc(PATH_MAX, GFP_KERNEL);
988 	if (!name) {
989 		ret = -ENOMEM;
990 		goto err;
991 	}
992 	ptr = name + PATH_MAX - 1;
993 	ptr[0] = '\0';
994 
995 	/*
996 	 * Walk up the subvolume trees in the tree of tree roots by root
997 	 * backrefs until we hit the top-level subvolume.
998 	 */
999 	while (subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
1000 		key.objectid = subvol_objectid;
1001 		key.type = BTRFS_ROOT_BACKREF_KEY;
1002 		key.offset = (u64)-1;
1003 
1004 		ret = btrfs_search_backwards(root, &key, path);
1005 		if (ret < 0) {
1006 			goto err;
1007 		} else if (ret > 0) {
1008 			ret = -ENOENT;
1009 			goto err;
1010 		}
1011 
1012 		subvol_objectid = key.offset;
1013 
1014 		root_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
1015 					  struct btrfs_root_ref);
1016 		len = btrfs_root_ref_name_len(path->nodes[0], root_ref);
1017 		ptr -= len + 1;
1018 		if (ptr < name) {
1019 			ret = -ENAMETOOLONG;
1020 			goto err;
1021 		}
1022 		read_extent_buffer(path->nodes[0], ptr + 1,
1023 				   (unsigned long)(root_ref + 1), len);
1024 		ptr[0] = '/';
1025 		dirid = btrfs_root_ref_dirid(path->nodes[0], root_ref);
1026 		btrfs_release_path(path);
1027 
1028 		fs_root = btrfs_get_fs_root(fs_info, subvol_objectid, true);
1029 		if (IS_ERR(fs_root)) {
1030 			ret = PTR_ERR(fs_root);
1031 			fs_root = NULL;
1032 			goto err;
1033 		}
1034 
1035 		/*
1036 		 * Walk up the filesystem tree by inode refs until we hit the
1037 		 * root directory.
1038 		 */
1039 		while (dirid != BTRFS_FIRST_FREE_OBJECTID) {
1040 			key.objectid = dirid;
1041 			key.type = BTRFS_INODE_REF_KEY;
1042 			key.offset = (u64)-1;
1043 
1044 			ret = btrfs_search_backwards(fs_root, &key, path);
1045 			if (ret < 0) {
1046 				goto err;
1047 			} else if (ret > 0) {
1048 				ret = -ENOENT;
1049 				goto err;
1050 			}
1051 
1052 			dirid = key.offset;
1053 
1054 			inode_ref = btrfs_item_ptr(path->nodes[0],
1055 						   path->slots[0],
1056 						   struct btrfs_inode_ref);
1057 			len = btrfs_inode_ref_name_len(path->nodes[0],
1058 						       inode_ref);
1059 			ptr -= len + 1;
1060 			if (ptr < name) {
1061 				ret = -ENAMETOOLONG;
1062 				goto err;
1063 			}
1064 			read_extent_buffer(path->nodes[0], ptr + 1,
1065 					   (unsigned long)(inode_ref + 1), len);
1066 			ptr[0] = '/';
1067 			btrfs_release_path(path);
1068 		}
1069 		btrfs_put_root(fs_root);
1070 		fs_root = NULL;
1071 	}
1072 
1073 	btrfs_free_path(path);
1074 	if (ptr == name + PATH_MAX - 1) {
1075 		name[0] = '/';
1076 		name[1] = '\0';
1077 	} else {
1078 		memmove(name, ptr, name + PATH_MAX - ptr);
1079 	}
1080 	return name;
1081 
1082 err:
1083 	btrfs_put_root(fs_root);
1084 	btrfs_free_path(path);
1085 	kfree(name);
1086 	return ERR_PTR(ret);
1087 }
1088 
1089 static int get_default_subvol_objectid(struct btrfs_fs_info *fs_info, u64 *objectid)
1090 {
1091 	struct btrfs_root *root = fs_info->tree_root;
1092 	struct btrfs_dir_item *di;
1093 	struct btrfs_path *path;
1094 	struct btrfs_key location;
1095 	struct fscrypt_str name = FSTR_INIT("default", 7);
1096 	u64 dir_id;
1097 
1098 	path = btrfs_alloc_path();
1099 	if (!path)
1100 		return -ENOMEM;
1101 
1102 	/*
1103 	 * Find the "default" dir item which points to the root item that we
1104 	 * will mount by default if we haven't been given a specific subvolume
1105 	 * to mount.
1106 	 */
1107 	dir_id = btrfs_super_root_dir(fs_info->super_copy);
1108 	di = btrfs_lookup_dir_item(NULL, root, path, dir_id, &name, 0);
1109 	if (IS_ERR(di)) {
1110 		btrfs_free_path(path);
1111 		return PTR_ERR(di);
1112 	}
1113 	if (!di) {
1114 		/*
1115 		 * Ok the default dir item isn't there.  This is weird since
1116 		 * it's always been there, but don't freak out, just try and
1117 		 * mount the top-level subvolume.
1118 		 */
1119 		btrfs_free_path(path);
1120 		*objectid = BTRFS_FS_TREE_OBJECTID;
1121 		return 0;
1122 	}
1123 
1124 	btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
1125 	btrfs_free_path(path);
1126 	*objectid = location.objectid;
1127 	return 0;
1128 }
1129 
1130 static int btrfs_fill_super(struct super_block *sb,
1131 			    struct btrfs_fs_devices *fs_devices,
1132 			    void *data)
1133 {
1134 	struct inode *inode;
1135 	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1136 	int err;
1137 
1138 	sb->s_maxbytes = MAX_LFS_FILESIZE;
1139 	sb->s_magic = BTRFS_SUPER_MAGIC;
1140 	sb->s_op = &btrfs_super_ops;
1141 	sb->s_d_op = &btrfs_dentry_operations;
1142 	sb->s_export_op = &btrfs_export_ops;
1143 #ifdef CONFIG_FS_VERITY
1144 	sb->s_vop = &btrfs_verityops;
1145 #endif
1146 	sb->s_xattr = btrfs_xattr_handlers;
1147 	sb->s_time_gran = 1;
1148 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
1149 	sb->s_flags |= SB_POSIXACL;
1150 #endif
1151 	sb->s_flags |= SB_I_VERSION;
1152 	sb->s_iflags |= SB_I_CGROUPWB;
1153 
1154 	err = super_setup_bdi(sb);
1155 	if (err) {
1156 		btrfs_err(fs_info, "super_setup_bdi failed");
1157 		return err;
1158 	}
1159 
1160 	err = open_ctree(sb, fs_devices, (char *)data);
1161 	if (err) {
1162 		btrfs_err(fs_info, "open_ctree failed");
1163 		return err;
1164 	}
1165 
1166 	inode = btrfs_iget(sb, BTRFS_FIRST_FREE_OBJECTID, fs_info->fs_root);
1167 	if (IS_ERR(inode)) {
1168 		err = PTR_ERR(inode);
1169 		btrfs_handle_fs_error(fs_info, err, NULL);
1170 		goto fail_close;
1171 	}
1172 
1173 	sb->s_root = d_make_root(inode);
1174 	if (!sb->s_root) {
1175 		err = -ENOMEM;
1176 		goto fail_close;
1177 	}
1178 
1179 	sb->s_flags |= SB_ACTIVE;
1180 	return 0;
1181 
1182 fail_close:
1183 	close_ctree(fs_info);
1184 	return err;
1185 }
1186 
1187 int btrfs_sync_fs(struct super_block *sb, int wait)
1188 {
1189 	struct btrfs_trans_handle *trans;
1190 	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1191 	struct btrfs_root *root = fs_info->tree_root;
1192 
1193 	trace_btrfs_sync_fs(fs_info, wait);
1194 
1195 	if (!wait) {
1196 		filemap_flush(fs_info->btree_inode->i_mapping);
1197 		return 0;
1198 	}
1199 
1200 	btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
1201 
1202 	trans = btrfs_attach_transaction_barrier(root);
1203 	if (IS_ERR(trans)) {
1204 		/* no transaction, don't bother */
1205 		if (PTR_ERR(trans) == -ENOENT) {
1206 			/*
1207 			 * Exit unless we have some pending changes
1208 			 * that need to go through commit
1209 			 */
1210 			if (!test_bit(BTRFS_FS_NEED_TRANS_COMMIT,
1211 				      &fs_info->flags))
1212 				return 0;
1213 			/*
1214 			 * A non-blocking test if the fs is frozen. We must not
1215 			 * start a new transaction here otherwise a deadlock
1216 			 * happens. The pending operations are delayed to the
1217 			 * next commit after thawing.
1218 			 */
1219 			if (sb_start_write_trylock(sb))
1220 				sb_end_write(sb);
1221 			else
1222 				return 0;
1223 			trans = btrfs_start_transaction(root, 0);
1224 		}
1225 		if (IS_ERR(trans))
1226 			return PTR_ERR(trans);
1227 	}
1228 	return btrfs_commit_transaction(trans);
1229 }
1230 
1231 static void print_rescue_option(struct seq_file *seq, const char *s, bool *printed)
1232 {
1233 	seq_printf(seq, "%s%s", (*printed) ? ":" : ",rescue=", s);
1234 	*printed = true;
1235 }
1236 
1237 static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
1238 {
1239 	struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
1240 	const char *compress_type;
1241 	const char *subvol_name;
1242 	bool printed = false;
1243 
1244 	if (btrfs_test_opt(info, DEGRADED))
1245 		seq_puts(seq, ",degraded");
1246 	if (btrfs_test_opt(info, NODATASUM))
1247 		seq_puts(seq, ",nodatasum");
1248 	if (btrfs_test_opt(info, NODATACOW))
1249 		seq_puts(seq, ",nodatacow");
1250 	if (btrfs_test_opt(info, NOBARRIER))
1251 		seq_puts(seq, ",nobarrier");
1252 	if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE)
1253 		seq_printf(seq, ",max_inline=%llu", info->max_inline);
1254 	if (info->thread_pool_size !=  min_t(unsigned long,
1255 					     num_online_cpus() + 2, 8))
1256 		seq_printf(seq, ",thread_pool=%u", info->thread_pool_size);
1257 	if (btrfs_test_opt(info, COMPRESS)) {
1258 		compress_type = btrfs_compress_type2str(info->compress_type);
1259 		if (btrfs_test_opt(info, FORCE_COMPRESS))
1260 			seq_printf(seq, ",compress-force=%s", compress_type);
1261 		else
1262 			seq_printf(seq, ",compress=%s", compress_type);
1263 		if (info->compress_level)
1264 			seq_printf(seq, ":%d", info->compress_level);
1265 	}
1266 	if (btrfs_test_opt(info, NOSSD))
1267 		seq_puts(seq, ",nossd");
1268 	if (btrfs_test_opt(info, SSD_SPREAD))
1269 		seq_puts(seq, ",ssd_spread");
1270 	else if (btrfs_test_opt(info, SSD))
1271 		seq_puts(seq, ",ssd");
1272 	if (btrfs_test_opt(info, NOTREELOG))
1273 		seq_puts(seq, ",notreelog");
1274 	if (btrfs_test_opt(info, NOLOGREPLAY))
1275 		print_rescue_option(seq, "nologreplay", &printed);
1276 	if (btrfs_test_opt(info, USEBACKUPROOT))
1277 		print_rescue_option(seq, "usebackuproot", &printed);
1278 	if (btrfs_test_opt(info, IGNOREBADROOTS))
1279 		print_rescue_option(seq, "ignorebadroots", &printed);
1280 	if (btrfs_test_opt(info, IGNOREDATACSUMS))
1281 		print_rescue_option(seq, "ignoredatacsums", &printed);
1282 	if (btrfs_test_opt(info, FLUSHONCOMMIT))
1283 		seq_puts(seq, ",flushoncommit");
1284 	if (btrfs_test_opt(info, DISCARD_SYNC))
1285 		seq_puts(seq, ",discard");
1286 	if (btrfs_test_opt(info, DISCARD_ASYNC))
1287 		seq_puts(seq, ",discard=async");
1288 	if (!(info->sb->s_flags & SB_POSIXACL))
1289 		seq_puts(seq, ",noacl");
1290 	if (btrfs_free_space_cache_v1_active(info))
1291 		seq_puts(seq, ",space_cache");
1292 	else if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE))
1293 		seq_puts(seq, ",space_cache=v2");
1294 	else
1295 		seq_puts(seq, ",nospace_cache");
1296 	if (btrfs_test_opt(info, RESCAN_UUID_TREE))
1297 		seq_puts(seq, ",rescan_uuid_tree");
1298 	if (btrfs_test_opt(info, CLEAR_CACHE))
1299 		seq_puts(seq, ",clear_cache");
1300 	if (btrfs_test_opt(info, USER_SUBVOL_RM_ALLOWED))
1301 		seq_puts(seq, ",user_subvol_rm_allowed");
1302 	if (btrfs_test_opt(info, ENOSPC_DEBUG))
1303 		seq_puts(seq, ",enospc_debug");
1304 	if (btrfs_test_opt(info, AUTO_DEFRAG))
1305 		seq_puts(seq, ",autodefrag");
1306 	if (btrfs_test_opt(info, SKIP_BALANCE))
1307 		seq_puts(seq, ",skip_balance");
1308 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
1309 	if (btrfs_test_opt(info, CHECK_INTEGRITY_DATA))
1310 		seq_puts(seq, ",check_int_data");
1311 	else if (btrfs_test_opt(info, CHECK_INTEGRITY))
1312 		seq_puts(seq, ",check_int");
1313 	if (info->check_integrity_print_mask)
1314 		seq_printf(seq, ",check_int_print_mask=%d",
1315 				info->check_integrity_print_mask);
1316 #endif
1317 	if (info->metadata_ratio)
1318 		seq_printf(seq, ",metadata_ratio=%u", info->metadata_ratio);
1319 	if (btrfs_test_opt(info, PANIC_ON_FATAL_ERROR))
1320 		seq_puts(seq, ",fatal_errors=panic");
1321 	if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL)
1322 		seq_printf(seq, ",commit=%u", info->commit_interval);
1323 #ifdef CONFIG_BTRFS_DEBUG
1324 	if (btrfs_test_opt(info, FRAGMENT_DATA))
1325 		seq_puts(seq, ",fragment=data");
1326 	if (btrfs_test_opt(info, FRAGMENT_METADATA))
1327 		seq_puts(seq, ",fragment=metadata");
1328 #endif
1329 	if (btrfs_test_opt(info, REF_VERIFY))
1330 		seq_puts(seq, ",ref_verify");
1331 	seq_printf(seq, ",subvolid=%llu",
1332 		  BTRFS_I(d_inode(dentry))->root->root_key.objectid);
1333 	subvol_name = btrfs_get_subvol_name_from_objectid(info,
1334 			BTRFS_I(d_inode(dentry))->root->root_key.objectid);
1335 	if (!IS_ERR(subvol_name)) {
1336 		seq_puts(seq, ",subvol=");
1337 		seq_escape(seq, subvol_name, " \t\n\\");
1338 		kfree(subvol_name);
1339 	}
1340 	return 0;
1341 }
1342 
1343 static int btrfs_test_super(struct super_block *s, void *data)
1344 {
1345 	struct btrfs_fs_info *p = data;
1346 	struct btrfs_fs_info *fs_info = btrfs_sb(s);
1347 
1348 	return fs_info->fs_devices == p->fs_devices;
1349 }
1350 
1351 static int btrfs_set_super(struct super_block *s, void *data)
1352 {
1353 	int err = set_anon_super(s, data);
1354 	if (!err)
1355 		s->s_fs_info = data;
1356 	return err;
1357 }
1358 
1359 /*
1360  * subvolumes are identified by ino 256
1361  */
1362 static inline int is_subvolume_inode(struct inode *inode)
1363 {
1364 	if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
1365 		return 1;
1366 	return 0;
1367 }
1368 
1369 static struct dentry *mount_subvol(const char *subvol_name, u64 subvol_objectid,
1370 				   struct vfsmount *mnt)
1371 {
1372 	struct dentry *root;
1373 	int ret;
1374 
1375 	if (!subvol_name) {
1376 		if (!subvol_objectid) {
1377 			ret = get_default_subvol_objectid(btrfs_sb(mnt->mnt_sb),
1378 							  &subvol_objectid);
1379 			if (ret) {
1380 				root = ERR_PTR(ret);
1381 				goto out;
1382 			}
1383 		}
1384 		subvol_name = btrfs_get_subvol_name_from_objectid(
1385 					btrfs_sb(mnt->mnt_sb), subvol_objectid);
1386 		if (IS_ERR(subvol_name)) {
1387 			root = ERR_CAST(subvol_name);
1388 			subvol_name = NULL;
1389 			goto out;
1390 		}
1391 
1392 	}
1393 
1394 	root = mount_subtree(mnt, subvol_name);
1395 	/* mount_subtree() drops our reference on the vfsmount. */
1396 	mnt = NULL;
1397 
1398 	if (!IS_ERR(root)) {
1399 		struct super_block *s = root->d_sb;
1400 		struct btrfs_fs_info *fs_info = btrfs_sb(s);
1401 		struct inode *root_inode = d_inode(root);
1402 		u64 root_objectid = BTRFS_I(root_inode)->root->root_key.objectid;
1403 
1404 		ret = 0;
1405 		if (!is_subvolume_inode(root_inode)) {
1406 			btrfs_err(fs_info, "'%s' is not a valid subvolume",
1407 			       subvol_name);
1408 			ret = -EINVAL;
1409 		}
1410 		if (subvol_objectid && root_objectid != subvol_objectid) {
1411 			/*
1412 			 * This will also catch a race condition where a
1413 			 * subvolume which was passed by ID is renamed and
1414 			 * another subvolume is renamed over the old location.
1415 			 */
1416 			btrfs_err(fs_info,
1417 				  "subvol '%s' does not match subvolid %llu",
1418 				  subvol_name, subvol_objectid);
1419 			ret = -EINVAL;
1420 		}
1421 		if (ret) {
1422 			dput(root);
1423 			root = ERR_PTR(ret);
1424 			deactivate_locked_super(s);
1425 		}
1426 	}
1427 
1428 out:
1429 	mntput(mnt);
1430 	kfree(subvol_name);
1431 	return root;
1432 }
1433 
1434 /*
1435  * Find a superblock for the given device / mount point.
1436  *
1437  * Note: This is based on mount_bdev from fs/super.c with a few additions
1438  *       for multiple device setup.  Make sure to keep it in sync.
1439  */
1440 static struct dentry *btrfs_mount_root(struct file_system_type *fs_type,
1441 		int flags, const char *device_name, void *data)
1442 {
1443 	struct block_device *bdev = NULL;
1444 	struct super_block *s;
1445 	struct btrfs_device *device = NULL;
1446 	struct btrfs_fs_devices *fs_devices = NULL;
1447 	struct btrfs_fs_info *fs_info = NULL;
1448 	void *new_sec_opts = NULL;
1449 	blk_mode_t mode = sb_open_mode(flags);
1450 	int error = 0;
1451 
1452 	if (data) {
1453 		error = security_sb_eat_lsm_opts(data, &new_sec_opts);
1454 		if (error)
1455 			return ERR_PTR(error);
1456 	}
1457 
1458 	/*
1459 	 * Setup a dummy root and fs_info for test/set super.  This is because
1460 	 * we don't actually fill this stuff out until open_ctree, but we need
1461 	 * then open_ctree will properly initialize the file system specific
1462 	 * settings later.  btrfs_init_fs_info initializes the static elements
1463 	 * of the fs_info (locks and such) to make cleanup easier if we find a
1464 	 * superblock with our given fs_devices later on at sget() time.
1465 	 */
1466 	fs_info = kvzalloc(sizeof(struct btrfs_fs_info), GFP_KERNEL);
1467 	if (!fs_info) {
1468 		error = -ENOMEM;
1469 		goto error_sec_opts;
1470 	}
1471 	btrfs_init_fs_info(fs_info);
1472 
1473 	fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
1474 	fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
1475 	if (!fs_info->super_copy || !fs_info->super_for_commit) {
1476 		error = -ENOMEM;
1477 		goto error_fs_info;
1478 	}
1479 
1480 	mutex_lock(&uuid_mutex);
1481 	error = btrfs_parse_device_options(data, mode);
1482 	if (error) {
1483 		mutex_unlock(&uuid_mutex);
1484 		goto error_fs_info;
1485 	}
1486 
1487 	device = btrfs_scan_one_device(device_name, mode);
1488 	if (IS_ERR(device)) {
1489 		mutex_unlock(&uuid_mutex);
1490 		error = PTR_ERR(device);
1491 		goto error_fs_info;
1492 	}
1493 
1494 	fs_devices = device->fs_devices;
1495 	fs_info->fs_devices = fs_devices;
1496 
1497 	error = btrfs_open_devices(fs_devices, mode, fs_type);
1498 	mutex_unlock(&uuid_mutex);
1499 	if (error)
1500 		goto error_fs_info;
1501 
1502 	if (!(flags & SB_RDONLY) && fs_devices->rw_devices == 0) {
1503 		error = -EACCES;
1504 		goto error_close_devices;
1505 	}
1506 
1507 	bdev = fs_devices->latest_dev->bdev;
1508 	s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | SB_NOSEC,
1509 		 fs_info);
1510 	if (IS_ERR(s)) {
1511 		error = PTR_ERR(s);
1512 		goto error_close_devices;
1513 	}
1514 
1515 	if (s->s_root) {
1516 		btrfs_close_devices(fs_devices);
1517 		btrfs_free_fs_info(fs_info);
1518 		if ((flags ^ s->s_flags) & SB_RDONLY)
1519 			error = -EBUSY;
1520 	} else {
1521 		snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev);
1522 		shrinker_debugfs_rename(&s->s_shrink, "sb-%s:%s", fs_type->name,
1523 					s->s_id);
1524 		btrfs_sb(s)->bdev_holder = fs_type;
1525 		error = btrfs_fill_super(s, fs_devices, data);
1526 	}
1527 	if (!error)
1528 		error = security_sb_set_mnt_opts(s, new_sec_opts, 0, NULL);
1529 	security_free_mnt_opts(&new_sec_opts);
1530 	if (error) {
1531 		deactivate_locked_super(s);
1532 		return ERR_PTR(error);
1533 	}
1534 
1535 	return dget(s->s_root);
1536 
1537 error_close_devices:
1538 	btrfs_close_devices(fs_devices);
1539 error_fs_info:
1540 	btrfs_free_fs_info(fs_info);
1541 error_sec_opts:
1542 	security_free_mnt_opts(&new_sec_opts);
1543 	return ERR_PTR(error);
1544 }
1545 
1546 /*
1547  * Mount function which is called by VFS layer.
1548  *
1549  * In order to allow mounting a subvolume directly, btrfs uses mount_subtree()
1550  * which needs vfsmount* of device's root (/).  This means device's root has to
1551  * be mounted internally in any case.
1552  *
1553  * Operation flow:
1554  *   1. Parse subvol id related options for later use in mount_subvol().
1555  *
1556  *   2. Mount device's root (/) by calling vfs_kern_mount().
1557  *
1558  *      NOTE: vfs_kern_mount() is used by VFS to call btrfs_mount() in the
1559  *      first place. In order to avoid calling btrfs_mount() again, we use
1560  *      different file_system_type which is not registered to VFS by
1561  *      register_filesystem() (btrfs_root_fs_type). As a result,
1562  *      btrfs_mount_root() is called. The return value will be used by
1563  *      mount_subtree() in mount_subvol().
1564  *
1565  *   3. Call mount_subvol() to get the dentry of subvolume. Since there is
1566  *      "btrfs subvolume set-default", mount_subvol() is called always.
1567  */
1568 static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
1569 		const char *device_name, void *data)
1570 {
1571 	struct vfsmount *mnt_root;
1572 	struct dentry *root;
1573 	char *subvol_name = NULL;
1574 	u64 subvol_objectid = 0;
1575 	int error = 0;
1576 
1577 	error = btrfs_parse_subvol_options(data, &subvol_name,
1578 					&subvol_objectid);
1579 	if (error) {
1580 		kfree(subvol_name);
1581 		return ERR_PTR(error);
1582 	}
1583 
1584 	/* mount device's root (/) */
1585 	mnt_root = vfs_kern_mount(&btrfs_root_fs_type, flags, device_name, data);
1586 	if (PTR_ERR_OR_ZERO(mnt_root) == -EBUSY) {
1587 		if (flags & SB_RDONLY) {
1588 			mnt_root = vfs_kern_mount(&btrfs_root_fs_type,
1589 				flags & ~SB_RDONLY, device_name, data);
1590 		} else {
1591 			mnt_root = vfs_kern_mount(&btrfs_root_fs_type,
1592 				flags | SB_RDONLY, device_name, data);
1593 			if (IS_ERR(mnt_root)) {
1594 				root = ERR_CAST(mnt_root);
1595 				kfree(subvol_name);
1596 				goto out;
1597 			}
1598 
1599 			down_write(&mnt_root->mnt_sb->s_umount);
1600 			error = btrfs_remount(mnt_root->mnt_sb, &flags, NULL);
1601 			up_write(&mnt_root->mnt_sb->s_umount);
1602 			if (error < 0) {
1603 				root = ERR_PTR(error);
1604 				mntput(mnt_root);
1605 				kfree(subvol_name);
1606 				goto out;
1607 			}
1608 		}
1609 	}
1610 	if (IS_ERR(mnt_root)) {
1611 		root = ERR_CAST(mnt_root);
1612 		kfree(subvol_name);
1613 		goto out;
1614 	}
1615 
1616 	/* mount_subvol() will free subvol_name and mnt_root */
1617 	root = mount_subvol(subvol_name, subvol_objectid, mnt_root);
1618 
1619 out:
1620 	return root;
1621 }
1622 
1623 static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
1624 				     u32 new_pool_size, u32 old_pool_size)
1625 {
1626 	if (new_pool_size == old_pool_size)
1627 		return;
1628 
1629 	fs_info->thread_pool_size = new_pool_size;
1630 
1631 	btrfs_info(fs_info, "resize thread pool %d -> %d",
1632 	       old_pool_size, new_pool_size);
1633 
1634 	btrfs_workqueue_set_max(fs_info->workers, new_pool_size);
1635 	btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size);
1636 	btrfs_workqueue_set_max(fs_info->caching_workers, new_pool_size);
1637 	workqueue_set_max_active(fs_info->endio_workers, new_pool_size);
1638 	workqueue_set_max_active(fs_info->endio_meta_workers, new_pool_size);
1639 	btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size);
1640 	btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
1641 	btrfs_workqueue_set_max(fs_info->delayed_workers, new_pool_size);
1642 }
1643 
1644 static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info,
1645 				       unsigned long old_opts, int flags)
1646 {
1647 	if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1648 	    (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1649 	     (flags & SB_RDONLY))) {
1650 		/* wait for any defraggers to finish */
1651 		wait_event(fs_info->transaction_wait,
1652 			   (atomic_read(&fs_info->defrag_running) == 0));
1653 		if (flags & SB_RDONLY)
1654 			sync_filesystem(fs_info->sb);
1655 	}
1656 }
1657 
1658 static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
1659 					 unsigned long old_opts)
1660 {
1661 	const bool cache_opt = btrfs_test_opt(fs_info, SPACE_CACHE);
1662 
1663 	/*
1664 	 * We need to cleanup all defragable inodes if the autodefragment is
1665 	 * close or the filesystem is read only.
1666 	 */
1667 	if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1668 	    (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) || sb_rdonly(fs_info->sb))) {
1669 		btrfs_cleanup_defrag_inodes(fs_info);
1670 	}
1671 
1672 	/* If we toggled discard async */
1673 	if (!btrfs_raw_test_opt(old_opts, DISCARD_ASYNC) &&
1674 	    btrfs_test_opt(fs_info, DISCARD_ASYNC))
1675 		btrfs_discard_resume(fs_info);
1676 	else if (btrfs_raw_test_opt(old_opts, DISCARD_ASYNC) &&
1677 		 !btrfs_test_opt(fs_info, DISCARD_ASYNC))
1678 		btrfs_discard_cleanup(fs_info);
1679 
1680 	/* If we toggled space cache */
1681 	if (cache_opt != btrfs_free_space_cache_v1_active(fs_info))
1682 		btrfs_set_free_space_cache_v1_active(fs_info, cache_opt);
1683 }
1684 
1685 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
1686 {
1687 	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1688 	unsigned old_flags = sb->s_flags;
1689 	unsigned long old_opts = fs_info->mount_opt;
1690 	unsigned long old_compress_type = fs_info->compress_type;
1691 	u64 old_max_inline = fs_info->max_inline;
1692 	u32 old_thread_pool_size = fs_info->thread_pool_size;
1693 	u32 old_metadata_ratio = fs_info->metadata_ratio;
1694 	int ret;
1695 
1696 	sync_filesystem(sb);
1697 	set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1698 
1699 	if (data) {
1700 		void *new_sec_opts = NULL;
1701 
1702 		ret = security_sb_eat_lsm_opts(data, &new_sec_opts);
1703 		if (!ret)
1704 			ret = security_sb_remount(sb, new_sec_opts);
1705 		security_free_mnt_opts(&new_sec_opts);
1706 		if (ret)
1707 			goto restore;
1708 	}
1709 
1710 	ret = btrfs_parse_options(fs_info, data, *flags);
1711 	if (ret)
1712 		goto restore;
1713 
1714 	ret = btrfs_check_features(fs_info, !(*flags & SB_RDONLY));
1715 	if (ret < 0)
1716 		goto restore;
1717 
1718 	btrfs_remount_begin(fs_info, old_opts, *flags);
1719 	btrfs_resize_thread_pool(fs_info,
1720 		fs_info->thread_pool_size, old_thread_pool_size);
1721 
1722 	if ((bool)btrfs_test_opt(fs_info, FREE_SPACE_TREE) !=
1723 	    (bool)btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE) &&
1724 	    (!sb_rdonly(sb) || (*flags & SB_RDONLY))) {
1725 		btrfs_warn(fs_info,
1726 		"remount supports changing free space tree only from ro to rw");
1727 		/* Make sure free space cache options match the state on disk */
1728 		if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE)) {
1729 			btrfs_set_opt(fs_info->mount_opt, FREE_SPACE_TREE);
1730 			btrfs_clear_opt(fs_info->mount_opt, SPACE_CACHE);
1731 		}
1732 		if (btrfs_free_space_cache_v1_active(fs_info)) {
1733 			btrfs_clear_opt(fs_info->mount_opt, FREE_SPACE_TREE);
1734 			btrfs_set_opt(fs_info->mount_opt, SPACE_CACHE);
1735 		}
1736 	}
1737 
1738 	if ((bool)(*flags & SB_RDONLY) == sb_rdonly(sb))
1739 		goto out;
1740 
1741 	if (*flags & SB_RDONLY) {
1742 		/*
1743 		 * this also happens on 'umount -rf' or on shutdown, when
1744 		 * the filesystem is busy.
1745 		 */
1746 		cancel_work_sync(&fs_info->async_reclaim_work);
1747 		cancel_work_sync(&fs_info->async_data_reclaim_work);
1748 
1749 		btrfs_discard_cleanup(fs_info);
1750 
1751 		/* wait for the uuid_scan task to finish */
1752 		down(&fs_info->uuid_tree_rescan_sem);
1753 		/* avoid complains from lockdep et al. */
1754 		up(&fs_info->uuid_tree_rescan_sem);
1755 
1756 		btrfs_set_sb_rdonly(sb);
1757 
1758 		/*
1759 		 * Setting SB_RDONLY will put the cleaner thread to
1760 		 * sleep at the next loop if it's already active.
1761 		 * If it's already asleep, we'll leave unused block
1762 		 * groups on disk until we're mounted read-write again
1763 		 * unless we clean them up here.
1764 		 */
1765 		btrfs_delete_unused_bgs(fs_info);
1766 
1767 		/*
1768 		 * The cleaner task could be already running before we set the
1769 		 * flag BTRFS_FS_STATE_RO (and SB_RDONLY in the superblock).
1770 		 * We must make sure that after we finish the remount, i.e. after
1771 		 * we call btrfs_commit_super(), the cleaner can no longer start
1772 		 * a transaction - either because it was dropping a dead root,
1773 		 * running delayed iputs or deleting an unused block group (the
1774 		 * cleaner picked a block group from the list of unused block
1775 		 * groups before we were able to in the previous call to
1776 		 * btrfs_delete_unused_bgs()).
1777 		 */
1778 		wait_on_bit(&fs_info->flags, BTRFS_FS_CLEANER_RUNNING,
1779 			    TASK_UNINTERRUPTIBLE);
1780 
1781 		/*
1782 		 * We've set the superblock to RO mode, so we might have made
1783 		 * the cleaner task sleep without running all pending delayed
1784 		 * iputs. Go through all the delayed iputs here, so that if an
1785 		 * unmount happens without remounting RW we don't end up at
1786 		 * finishing close_ctree() with a non-empty list of delayed
1787 		 * iputs.
1788 		 */
1789 		btrfs_run_delayed_iputs(fs_info);
1790 
1791 		btrfs_dev_replace_suspend_for_unmount(fs_info);
1792 		btrfs_scrub_cancel(fs_info);
1793 		btrfs_pause_balance(fs_info);
1794 
1795 		/*
1796 		 * Pause the qgroup rescan worker if it is running. We don't want
1797 		 * it to be still running after we are in RO mode, as after that,
1798 		 * by the time we unmount, it might have left a transaction open,
1799 		 * so we would leak the transaction and/or crash.
1800 		 */
1801 		btrfs_qgroup_wait_for_completion(fs_info, false);
1802 
1803 		ret = btrfs_commit_super(fs_info);
1804 		if (ret)
1805 			goto restore;
1806 	} else {
1807 		if (BTRFS_FS_ERROR(fs_info)) {
1808 			btrfs_err(fs_info,
1809 				"Remounting read-write after error is not allowed");
1810 			ret = -EINVAL;
1811 			goto restore;
1812 		}
1813 		if (fs_info->fs_devices->rw_devices == 0) {
1814 			ret = -EACCES;
1815 			goto restore;
1816 		}
1817 
1818 		if (!btrfs_check_rw_degradable(fs_info, NULL)) {
1819 			btrfs_warn(fs_info,
1820 		"too many missing devices, writable remount is not allowed");
1821 			ret = -EACCES;
1822 			goto restore;
1823 		}
1824 
1825 		if (btrfs_super_log_root(fs_info->super_copy) != 0) {
1826 			btrfs_warn(fs_info,
1827 		"mount required to replay tree-log, cannot remount read-write");
1828 			ret = -EINVAL;
1829 			goto restore;
1830 		}
1831 
1832 		/*
1833 		 * NOTE: when remounting with a change that does writes, don't
1834 		 * put it anywhere above this point, as we are not sure to be
1835 		 * safe to write until we pass the above checks.
1836 		 */
1837 		ret = btrfs_start_pre_rw_mount(fs_info);
1838 		if (ret)
1839 			goto restore;
1840 
1841 		btrfs_clear_sb_rdonly(sb);
1842 
1843 		set_bit(BTRFS_FS_OPEN, &fs_info->flags);
1844 
1845 		/*
1846 		 * If we've gone from readonly -> read/write, we need to get
1847 		 * our sync/async discard lists in the right state.
1848 		 */
1849 		btrfs_discard_resume(fs_info);
1850 	}
1851 out:
1852 	/*
1853 	 * We need to set SB_I_VERSION here otherwise it'll get cleared by VFS,
1854 	 * since the absence of the flag means it can be toggled off by remount.
1855 	 */
1856 	*flags |= SB_I_VERSION;
1857 
1858 	wake_up_process(fs_info->transaction_kthread);
1859 	btrfs_remount_cleanup(fs_info, old_opts);
1860 	btrfs_clear_oneshot_options(fs_info);
1861 	clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1862 
1863 	return 0;
1864 
1865 restore:
1866 	/* We've hit an error - don't reset SB_RDONLY */
1867 	if (sb_rdonly(sb))
1868 		old_flags |= SB_RDONLY;
1869 	if (!(old_flags & SB_RDONLY))
1870 		clear_bit(BTRFS_FS_STATE_RO, &fs_info->fs_state);
1871 	sb->s_flags = old_flags;
1872 	fs_info->mount_opt = old_opts;
1873 	fs_info->compress_type = old_compress_type;
1874 	fs_info->max_inline = old_max_inline;
1875 	btrfs_resize_thread_pool(fs_info,
1876 		old_thread_pool_size, fs_info->thread_pool_size);
1877 	fs_info->metadata_ratio = old_metadata_ratio;
1878 	btrfs_remount_cleanup(fs_info, old_opts);
1879 	clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1880 
1881 	return ret;
1882 }
1883 
1884 /* Used to sort the devices by max_avail(descending sort) */
1885 static int btrfs_cmp_device_free_bytes(const void *a, const void *b)
1886 {
1887 	const struct btrfs_device_info *dev_info1 = a;
1888 	const struct btrfs_device_info *dev_info2 = b;
1889 
1890 	if (dev_info1->max_avail > dev_info2->max_avail)
1891 		return -1;
1892 	else if (dev_info1->max_avail < dev_info2->max_avail)
1893 		return 1;
1894 	return 0;
1895 }
1896 
1897 /*
1898  * sort the devices by max_avail, in which max free extent size of each device
1899  * is stored.(Descending Sort)
1900  */
1901 static inline void btrfs_descending_sort_devices(
1902 					struct btrfs_device_info *devices,
1903 					size_t nr_devices)
1904 {
1905 	sort(devices, nr_devices, sizeof(struct btrfs_device_info),
1906 	     btrfs_cmp_device_free_bytes, NULL);
1907 }
1908 
1909 /*
1910  * The helper to calc the free space on the devices that can be used to store
1911  * file data.
1912  */
1913 static inline int btrfs_calc_avail_data_space(struct btrfs_fs_info *fs_info,
1914 					      u64 *free_bytes)
1915 {
1916 	struct btrfs_device_info *devices_info;
1917 	struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
1918 	struct btrfs_device *device;
1919 	u64 type;
1920 	u64 avail_space;
1921 	u64 min_stripe_size;
1922 	int num_stripes = 1;
1923 	int i = 0, nr_devices;
1924 	const struct btrfs_raid_attr *rattr;
1925 
1926 	/*
1927 	 * We aren't under the device list lock, so this is racy-ish, but good
1928 	 * enough for our purposes.
1929 	 */
1930 	nr_devices = fs_info->fs_devices->open_devices;
1931 	if (!nr_devices) {
1932 		smp_mb();
1933 		nr_devices = fs_info->fs_devices->open_devices;
1934 		ASSERT(nr_devices);
1935 		if (!nr_devices) {
1936 			*free_bytes = 0;
1937 			return 0;
1938 		}
1939 	}
1940 
1941 	devices_info = kmalloc_array(nr_devices, sizeof(*devices_info),
1942 			       GFP_KERNEL);
1943 	if (!devices_info)
1944 		return -ENOMEM;
1945 
1946 	/* calc min stripe number for data space allocation */
1947 	type = btrfs_data_alloc_profile(fs_info);
1948 	rattr = &btrfs_raid_array[btrfs_bg_flags_to_raid_index(type)];
1949 
1950 	if (type & BTRFS_BLOCK_GROUP_RAID0)
1951 		num_stripes = nr_devices;
1952 	else if (type & BTRFS_BLOCK_GROUP_RAID1_MASK)
1953 		num_stripes = rattr->ncopies;
1954 	else if (type & BTRFS_BLOCK_GROUP_RAID10)
1955 		num_stripes = 4;
1956 
1957 	/* Adjust for more than 1 stripe per device */
1958 	min_stripe_size = rattr->dev_stripes * BTRFS_STRIPE_LEN;
1959 
1960 	rcu_read_lock();
1961 	list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
1962 		if (!test_bit(BTRFS_DEV_STATE_IN_FS_METADATA,
1963 						&device->dev_state) ||
1964 		    !device->bdev ||
1965 		    test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state))
1966 			continue;
1967 
1968 		if (i >= nr_devices)
1969 			break;
1970 
1971 		avail_space = device->total_bytes - device->bytes_used;
1972 
1973 		/* align with stripe_len */
1974 		avail_space = rounddown(avail_space, BTRFS_STRIPE_LEN);
1975 
1976 		/*
1977 		 * Ensure we have at least min_stripe_size on top of the
1978 		 * reserved space on the device.
1979 		 */
1980 		if (avail_space <= BTRFS_DEVICE_RANGE_RESERVED + min_stripe_size)
1981 			continue;
1982 
1983 		avail_space -= BTRFS_DEVICE_RANGE_RESERVED;
1984 
1985 		devices_info[i].dev = device;
1986 		devices_info[i].max_avail = avail_space;
1987 
1988 		i++;
1989 	}
1990 	rcu_read_unlock();
1991 
1992 	nr_devices = i;
1993 
1994 	btrfs_descending_sort_devices(devices_info, nr_devices);
1995 
1996 	i = nr_devices - 1;
1997 	avail_space = 0;
1998 	while (nr_devices >= rattr->devs_min) {
1999 		num_stripes = min(num_stripes, nr_devices);
2000 
2001 		if (devices_info[i].max_avail >= min_stripe_size) {
2002 			int j;
2003 			u64 alloc_size;
2004 
2005 			avail_space += devices_info[i].max_avail * num_stripes;
2006 			alloc_size = devices_info[i].max_avail;
2007 			for (j = i + 1 - num_stripes; j <= i; j++)
2008 				devices_info[j].max_avail -= alloc_size;
2009 		}
2010 		i--;
2011 		nr_devices--;
2012 	}
2013 
2014 	kfree(devices_info);
2015 	*free_bytes = avail_space;
2016 	return 0;
2017 }
2018 
2019 /*
2020  * Calculate numbers for 'df', pessimistic in case of mixed raid profiles.
2021  *
2022  * If there's a redundant raid level at DATA block groups, use the respective
2023  * multiplier to scale the sizes.
2024  *
2025  * Unused device space usage is based on simulating the chunk allocator
2026  * algorithm that respects the device sizes and order of allocations.  This is
2027  * a close approximation of the actual use but there are other factors that may
2028  * change the result (like a new metadata chunk).
2029  *
2030  * If metadata is exhausted, f_bavail will be 0.
2031  */
2032 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
2033 {
2034 	struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
2035 	struct btrfs_super_block *disk_super = fs_info->super_copy;
2036 	struct btrfs_space_info *found;
2037 	u64 total_used = 0;
2038 	u64 total_free_data = 0;
2039 	u64 total_free_meta = 0;
2040 	u32 bits = fs_info->sectorsize_bits;
2041 	__be32 *fsid = (__be32 *)fs_info->fs_devices->fsid;
2042 	unsigned factor = 1;
2043 	struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
2044 	int ret;
2045 	u64 thresh = 0;
2046 	int mixed = 0;
2047 
2048 	list_for_each_entry(found, &fs_info->space_info, list) {
2049 		if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
2050 			int i;
2051 
2052 			total_free_data += found->disk_total - found->disk_used;
2053 			total_free_data -=
2054 				btrfs_account_ro_block_groups_free_space(found);
2055 
2056 			for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
2057 				if (!list_empty(&found->block_groups[i]))
2058 					factor = btrfs_bg_type_to_factor(
2059 						btrfs_raid_array[i].bg_flag);
2060 			}
2061 		}
2062 
2063 		/*
2064 		 * Metadata in mixed block group profiles are accounted in data
2065 		 */
2066 		if (!mixed && found->flags & BTRFS_BLOCK_GROUP_METADATA) {
2067 			if (found->flags & BTRFS_BLOCK_GROUP_DATA)
2068 				mixed = 1;
2069 			else
2070 				total_free_meta += found->disk_total -
2071 					found->disk_used;
2072 		}
2073 
2074 		total_used += found->disk_used;
2075 	}
2076 
2077 	buf->f_blocks = div_u64(btrfs_super_total_bytes(disk_super), factor);
2078 	buf->f_blocks >>= bits;
2079 	buf->f_bfree = buf->f_blocks - (div_u64(total_used, factor) >> bits);
2080 
2081 	/* Account global block reserve as used, it's in logical size already */
2082 	spin_lock(&block_rsv->lock);
2083 	/* Mixed block groups accounting is not byte-accurate, avoid overflow */
2084 	if (buf->f_bfree >= block_rsv->size >> bits)
2085 		buf->f_bfree -= block_rsv->size >> bits;
2086 	else
2087 		buf->f_bfree = 0;
2088 	spin_unlock(&block_rsv->lock);
2089 
2090 	buf->f_bavail = div_u64(total_free_data, factor);
2091 	ret = btrfs_calc_avail_data_space(fs_info, &total_free_data);
2092 	if (ret)
2093 		return ret;
2094 	buf->f_bavail += div_u64(total_free_data, factor);
2095 	buf->f_bavail = buf->f_bavail >> bits;
2096 
2097 	/*
2098 	 * We calculate the remaining metadata space minus global reserve. If
2099 	 * this is (supposedly) smaller than zero, there's no space. But this
2100 	 * does not hold in practice, the exhausted state happens where's still
2101 	 * some positive delta. So we apply some guesswork and compare the
2102 	 * delta to a 4M threshold.  (Practically observed delta was ~2M.)
2103 	 *
2104 	 * We probably cannot calculate the exact threshold value because this
2105 	 * depends on the internal reservations requested by various
2106 	 * operations, so some operations that consume a few metadata will
2107 	 * succeed even if the Avail is zero. But this is better than the other
2108 	 * way around.
2109 	 */
2110 	thresh = SZ_4M;
2111 
2112 	/*
2113 	 * We only want to claim there's no available space if we can no longer
2114 	 * allocate chunks for our metadata profile and our global reserve will
2115 	 * not fit in the free metadata space.  If we aren't ->full then we
2116 	 * still can allocate chunks and thus are fine using the currently
2117 	 * calculated f_bavail.
2118 	 */
2119 	if (!mixed && block_rsv->space_info->full &&
2120 	    (total_free_meta < thresh || total_free_meta - thresh < block_rsv->size))
2121 		buf->f_bavail = 0;
2122 
2123 	buf->f_type = BTRFS_SUPER_MAGIC;
2124 	buf->f_bsize = dentry->d_sb->s_blocksize;
2125 	buf->f_namelen = BTRFS_NAME_LEN;
2126 
2127 	/* We treat it as constant endianness (it doesn't matter _which_)
2128 	   because we want the fsid to come out the same whether mounted
2129 	   on a big-endian or little-endian host */
2130 	buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
2131 	buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
2132 	/* Mask in the root object ID too, to disambiguate subvols */
2133 	buf->f_fsid.val[0] ^=
2134 		BTRFS_I(d_inode(dentry))->root->root_key.objectid >> 32;
2135 	buf->f_fsid.val[1] ^=
2136 		BTRFS_I(d_inode(dentry))->root->root_key.objectid;
2137 
2138 	return 0;
2139 }
2140 
2141 static void btrfs_kill_super(struct super_block *sb)
2142 {
2143 	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2144 	kill_anon_super(sb);
2145 	btrfs_free_fs_info(fs_info);
2146 }
2147 
2148 static struct file_system_type btrfs_fs_type = {
2149 	.owner		= THIS_MODULE,
2150 	.name		= "btrfs",
2151 	.mount		= btrfs_mount,
2152 	.kill_sb	= btrfs_kill_super,
2153 	.fs_flags	= FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,
2154 };
2155 
2156 static struct file_system_type btrfs_root_fs_type = {
2157 	.owner		= THIS_MODULE,
2158 	.name		= "btrfs",
2159 	.mount		= btrfs_mount_root,
2160 	.kill_sb	= btrfs_kill_super,
2161 	.fs_flags	= FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA | FS_ALLOW_IDMAP,
2162 };
2163 
2164 MODULE_ALIAS_FS("btrfs");
2165 
2166 static int btrfs_control_open(struct inode *inode, struct file *file)
2167 {
2168 	/*
2169 	 * The control file's private_data is used to hold the
2170 	 * transaction when it is started and is used to keep
2171 	 * track of whether a transaction is already in progress.
2172 	 */
2173 	file->private_data = NULL;
2174 	return 0;
2175 }
2176 
2177 /*
2178  * Used by /dev/btrfs-control for devices ioctls.
2179  */
2180 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
2181 				unsigned long arg)
2182 {
2183 	struct btrfs_ioctl_vol_args *vol;
2184 	struct btrfs_device *device = NULL;
2185 	dev_t devt = 0;
2186 	int ret = -ENOTTY;
2187 
2188 	if (!capable(CAP_SYS_ADMIN))
2189 		return -EPERM;
2190 
2191 	vol = memdup_user((void __user *)arg, sizeof(*vol));
2192 	if (IS_ERR(vol))
2193 		return PTR_ERR(vol);
2194 	vol->name[BTRFS_PATH_NAME_MAX] = '\0';
2195 
2196 	switch (cmd) {
2197 	case BTRFS_IOC_SCAN_DEV:
2198 		mutex_lock(&uuid_mutex);
2199 		device = btrfs_scan_one_device(vol->name, BLK_OPEN_READ);
2200 		ret = PTR_ERR_OR_ZERO(device);
2201 		mutex_unlock(&uuid_mutex);
2202 		break;
2203 	case BTRFS_IOC_FORGET_DEV:
2204 		if (vol->name[0] != 0) {
2205 			ret = lookup_bdev(vol->name, &devt);
2206 			if (ret)
2207 				break;
2208 		}
2209 		ret = btrfs_forget_devices(devt);
2210 		break;
2211 	case BTRFS_IOC_DEVICES_READY:
2212 		mutex_lock(&uuid_mutex);
2213 		device = btrfs_scan_one_device(vol->name, BLK_OPEN_READ);
2214 		if (IS_ERR(device)) {
2215 			mutex_unlock(&uuid_mutex);
2216 			ret = PTR_ERR(device);
2217 			break;
2218 		}
2219 		ret = !(device->fs_devices->num_devices ==
2220 			device->fs_devices->total_devices);
2221 		mutex_unlock(&uuid_mutex);
2222 		break;
2223 	case BTRFS_IOC_GET_SUPPORTED_FEATURES:
2224 		ret = btrfs_ioctl_get_supported_features((void __user*)arg);
2225 		break;
2226 	}
2227 
2228 	kfree(vol);
2229 	return ret;
2230 }
2231 
2232 static int btrfs_freeze(struct super_block *sb)
2233 {
2234 	struct btrfs_trans_handle *trans;
2235 	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2236 	struct btrfs_root *root = fs_info->tree_root;
2237 
2238 	set_bit(BTRFS_FS_FROZEN, &fs_info->flags);
2239 	/*
2240 	 * We don't need a barrier here, we'll wait for any transaction that
2241 	 * could be in progress on other threads (and do delayed iputs that
2242 	 * we want to avoid on a frozen filesystem), or do the commit
2243 	 * ourselves.
2244 	 */
2245 	trans = btrfs_attach_transaction_barrier(root);
2246 	if (IS_ERR(trans)) {
2247 		/* no transaction, don't bother */
2248 		if (PTR_ERR(trans) == -ENOENT)
2249 			return 0;
2250 		return PTR_ERR(trans);
2251 	}
2252 	return btrfs_commit_transaction(trans);
2253 }
2254 
2255 static int check_dev_super(struct btrfs_device *dev)
2256 {
2257 	struct btrfs_fs_info *fs_info = dev->fs_info;
2258 	struct btrfs_super_block *sb;
2259 	u16 csum_type;
2260 	int ret = 0;
2261 
2262 	/* This should be called with fs still frozen. */
2263 	ASSERT(test_bit(BTRFS_FS_FROZEN, &fs_info->flags));
2264 
2265 	/* Missing dev, no need to check. */
2266 	if (!dev->bdev)
2267 		return 0;
2268 
2269 	/* Only need to check the primary super block. */
2270 	sb = btrfs_read_dev_one_super(dev->bdev, 0, true);
2271 	if (IS_ERR(sb))
2272 		return PTR_ERR(sb);
2273 
2274 	/* Verify the checksum. */
2275 	csum_type = btrfs_super_csum_type(sb);
2276 	if (csum_type != btrfs_super_csum_type(fs_info->super_copy)) {
2277 		btrfs_err(fs_info, "csum type changed, has %u expect %u",
2278 			  csum_type, btrfs_super_csum_type(fs_info->super_copy));
2279 		ret = -EUCLEAN;
2280 		goto out;
2281 	}
2282 
2283 	if (btrfs_check_super_csum(fs_info, sb)) {
2284 		btrfs_err(fs_info, "csum for on-disk super block no longer matches");
2285 		ret = -EUCLEAN;
2286 		goto out;
2287 	}
2288 
2289 	/* Btrfs_validate_super() includes fsid check against super->fsid. */
2290 	ret = btrfs_validate_super(fs_info, sb, 0);
2291 	if (ret < 0)
2292 		goto out;
2293 
2294 	if (btrfs_super_generation(sb) != fs_info->last_trans_committed) {
2295 		btrfs_err(fs_info, "transid mismatch, has %llu expect %llu",
2296 			btrfs_super_generation(sb),
2297 			fs_info->last_trans_committed);
2298 		ret = -EUCLEAN;
2299 		goto out;
2300 	}
2301 out:
2302 	btrfs_release_disk_super(sb);
2303 	return ret;
2304 }
2305 
2306 static int btrfs_unfreeze(struct super_block *sb)
2307 {
2308 	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2309 	struct btrfs_device *device;
2310 	int ret = 0;
2311 
2312 	/*
2313 	 * Make sure the fs is not changed by accident (like hibernation then
2314 	 * modified by other OS).
2315 	 * If we found anything wrong, we mark the fs error immediately.
2316 	 *
2317 	 * And since the fs is frozen, no one can modify the fs yet, thus
2318 	 * we don't need to hold device_list_mutex.
2319 	 */
2320 	list_for_each_entry(device, &fs_info->fs_devices->devices, dev_list) {
2321 		ret = check_dev_super(device);
2322 		if (ret < 0) {
2323 			btrfs_handle_fs_error(fs_info, ret,
2324 				"super block on devid %llu got modified unexpectedly",
2325 				device->devid);
2326 			break;
2327 		}
2328 	}
2329 	clear_bit(BTRFS_FS_FROZEN, &fs_info->flags);
2330 
2331 	/*
2332 	 * We still return 0, to allow VFS layer to unfreeze the fs even the
2333 	 * above checks failed. Since the fs is either fine or read-only, we're
2334 	 * safe to continue, without causing further damage.
2335 	 */
2336 	return 0;
2337 }
2338 
2339 static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
2340 {
2341 	struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
2342 
2343 	/*
2344 	 * There should be always a valid pointer in latest_dev, it may be stale
2345 	 * for a short moment in case it's being deleted but still valid until
2346 	 * the end of RCU grace period.
2347 	 */
2348 	rcu_read_lock();
2349 	seq_escape(m, btrfs_dev_name(fs_info->fs_devices->latest_dev), " \t\n\\");
2350 	rcu_read_unlock();
2351 
2352 	return 0;
2353 }
2354 
2355 static const struct super_operations btrfs_super_ops = {
2356 	.drop_inode	= btrfs_drop_inode,
2357 	.evict_inode	= btrfs_evict_inode,
2358 	.put_super	= btrfs_put_super,
2359 	.sync_fs	= btrfs_sync_fs,
2360 	.show_options	= btrfs_show_options,
2361 	.show_devname	= btrfs_show_devname,
2362 	.alloc_inode	= btrfs_alloc_inode,
2363 	.destroy_inode	= btrfs_destroy_inode,
2364 	.free_inode	= btrfs_free_inode,
2365 	.statfs		= btrfs_statfs,
2366 	.remount_fs	= btrfs_remount,
2367 	.freeze_fs	= btrfs_freeze,
2368 	.unfreeze_fs	= btrfs_unfreeze,
2369 };
2370 
2371 static const struct file_operations btrfs_ctl_fops = {
2372 	.open = btrfs_control_open,
2373 	.unlocked_ioctl	 = btrfs_control_ioctl,
2374 	.compat_ioctl = compat_ptr_ioctl,
2375 	.owner	 = THIS_MODULE,
2376 	.llseek = noop_llseek,
2377 };
2378 
2379 static struct miscdevice btrfs_misc = {
2380 	.minor		= BTRFS_MINOR,
2381 	.name		= "btrfs-control",
2382 	.fops		= &btrfs_ctl_fops
2383 };
2384 
2385 MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
2386 MODULE_ALIAS("devname:btrfs-control");
2387 
2388 static int __init btrfs_interface_init(void)
2389 {
2390 	return misc_register(&btrfs_misc);
2391 }
2392 
2393 static __cold void btrfs_interface_exit(void)
2394 {
2395 	misc_deregister(&btrfs_misc);
2396 }
2397 
2398 static int __init btrfs_print_mod_info(void)
2399 {
2400 	static const char options[] = ""
2401 #ifdef CONFIG_BTRFS_DEBUG
2402 			", debug=on"
2403 #endif
2404 #ifdef CONFIG_BTRFS_ASSERT
2405 			", assert=on"
2406 #endif
2407 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
2408 			", integrity-checker=on"
2409 #endif
2410 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
2411 			", ref-verify=on"
2412 #endif
2413 #ifdef CONFIG_BLK_DEV_ZONED
2414 			", zoned=yes"
2415 #else
2416 			", zoned=no"
2417 #endif
2418 #ifdef CONFIG_FS_VERITY
2419 			", fsverity=yes"
2420 #else
2421 			", fsverity=no"
2422 #endif
2423 			;
2424 	pr_info("Btrfs loaded%s\n", options);
2425 	return 0;
2426 }
2427 
2428 static int register_btrfs(void)
2429 {
2430 	return register_filesystem(&btrfs_fs_type);
2431 }
2432 
2433 static void unregister_btrfs(void)
2434 {
2435 	unregister_filesystem(&btrfs_fs_type);
2436 }
2437 
2438 /* Helper structure for long init/exit functions. */
2439 struct init_sequence {
2440 	int (*init_func)(void);
2441 	/* Can be NULL if the init_func doesn't need cleanup. */
2442 	void (*exit_func)(void);
2443 };
2444 
2445 static const struct init_sequence mod_init_seq[] = {
2446 	{
2447 		.init_func = btrfs_props_init,
2448 		.exit_func = NULL,
2449 	}, {
2450 		.init_func = btrfs_init_sysfs,
2451 		.exit_func = btrfs_exit_sysfs,
2452 	}, {
2453 		.init_func = btrfs_init_compress,
2454 		.exit_func = btrfs_exit_compress,
2455 	}, {
2456 		.init_func = btrfs_init_cachep,
2457 		.exit_func = btrfs_destroy_cachep,
2458 	}, {
2459 		.init_func = btrfs_transaction_init,
2460 		.exit_func = btrfs_transaction_exit,
2461 	}, {
2462 		.init_func = btrfs_ctree_init,
2463 		.exit_func = btrfs_ctree_exit,
2464 	}, {
2465 		.init_func = btrfs_free_space_init,
2466 		.exit_func = btrfs_free_space_exit,
2467 	}, {
2468 		.init_func = extent_state_init_cachep,
2469 		.exit_func = extent_state_free_cachep,
2470 	}, {
2471 		.init_func = extent_buffer_init_cachep,
2472 		.exit_func = extent_buffer_free_cachep,
2473 	}, {
2474 		.init_func = btrfs_bioset_init,
2475 		.exit_func = btrfs_bioset_exit,
2476 	}, {
2477 		.init_func = extent_map_init,
2478 		.exit_func = extent_map_exit,
2479 	}, {
2480 		.init_func = ordered_data_init,
2481 		.exit_func = ordered_data_exit,
2482 	}, {
2483 		.init_func = btrfs_delayed_inode_init,
2484 		.exit_func = btrfs_delayed_inode_exit,
2485 	}, {
2486 		.init_func = btrfs_auto_defrag_init,
2487 		.exit_func = btrfs_auto_defrag_exit,
2488 	}, {
2489 		.init_func = btrfs_delayed_ref_init,
2490 		.exit_func = btrfs_delayed_ref_exit,
2491 	}, {
2492 		.init_func = btrfs_prelim_ref_init,
2493 		.exit_func = btrfs_prelim_ref_exit,
2494 	}, {
2495 		.init_func = btrfs_interface_init,
2496 		.exit_func = btrfs_interface_exit,
2497 	}, {
2498 		.init_func = btrfs_print_mod_info,
2499 		.exit_func = NULL,
2500 	}, {
2501 		.init_func = btrfs_run_sanity_tests,
2502 		.exit_func = NULL,
2503 	}, {
2504 		.init_func = register_btrfs,
2505 		.exit_func = unregister_btrfs,
2506 	}
2507 };
2508 
2509 static bool mod_init_result[ARRAY_SIZE(mod_init_seq)];
2510 
2511 static __always_inline void btrfs_exit_btrfs_fs(void)
2512 {
2513 	int i;
2514 
2515 	for (i = ARRAY_SIZE(mod_init_seq) - 1; i >= 0; i--) {
2516 		if (!mod_init_result[i])
2517 			continue;
2518 		if (mod_init_seq[i].exit_func)
2519 			mod_init_seq[i].exit_func();
2520 		mod_init_result[i] = false;
2521 	}
2522 }
2523 
2524 static void __exit exit_btrfs_fs(void)
2525 {
2526 	btrfs_exit_btrfs_fs();
2527 	btrfs_cleanup_fs_uuids();
2528 }
2529 
2530 static int __init init_btrfs_fs(void)
2531 {
2532 	int ret;
2533 	int i;
2534 
2535 	for (i = 0; i < ARRAY_SIZE(mod_init_seq); i++) {
2536 		ASSERT(!mod_init_result[i]);
2537 		ret = mod_init_seq[i].init_func();
2538 		if (ret < 0) {
2539 			btrfs_exit_btrfs_fs();
2540 			return ret;
2541 		}
2542 		mod_init_result[i] = true;
2543 	}
2544 	return 0;
2545 }
2546 
2547 late_initcall(init_btrfs_fs);
2548 module_exit(exit_btrfs_fs)
2549 
2550 MODULE_LICENSE("GPL");
2551 MODULE_SOFTDEP("pre: crc32c");
2552 MODULE_SOFTDEP("pre: xxhash64");
2553 MODULE_SOFTDEP("pre: sha256");
2554 MODULE_SOFTDEP("pre: blake2b-256");
2555