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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dledford/rdma
[mirror_ubuntu-artful-kernel.git] / fs / btrfs / super.c
1 /*
2 * Copyright (C) 2007 Oracle. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18
19 #include <linux/blkdev.h>
20 #include <linux/module.h>
21 #include <linux/buffer_head.h>
22 #include <linux/fs.h>
23 #include <linux/pagemap.h>
24 #include <linux/highmem.h>
25 #include <linux/time.h>
26 #include <linux/init.h>
27 #include <linux/seq_file.h>
28 #include <linux/string.h>
29 #include <linux/backing-dev.h>
30 #include <linux/mount.h>
31 #include <linux/mpage.h>
32 #include <linux/swap.h>
33 #include <linux/writeback.h>
34 #include <linux/statfs.h>
35 #include <linux/compat.h>
36 #include <linux/parser.h>
37 #include <linux/ctype.h>
38 #include <linux/namei.h>
39 #include <linux/miscdevice.h>
40 #include <linux/magic.h>
41 #include <linux/slab.h>
42 #include <linux/cleancache.h>
43 #include <linux/ratelimit.h>
44 #include <linux/btrfs.h>
45 #include "delayed-inode.h"
46 #include "ctree.h"
47 #include "disk-io.h"
48 #include "transaction.h"
49 #include "btrfs_inode.h"
50 #include "print-tree.h"
51 #include "hash.h"
52 #include "props.h"
53 #include "xattr.h"
54 #include "volumes.h"
55 #include "export.h"
56 #include "compression.h"
57 #include "rcu-string.h"
58 #include "dev-replace.h"
59 #include "free-space-cache.h"
60 #include "backref.h"
61 #include "tests/btrfs-tests.h"
62
63 #include "qgroup.h"
64 #define CREATE_TRACE_POINTS
65 #include <trace/events/btrfs.h>
66
67 static const struct super_operations btrfs_super_ops;
68 static struct file_system_type btrfs_fs_type;
69
70 static int btrfs_remount(struct super_block *sb, int *flags, char *data);
71
72 const char *btrfs_decode_error(int errno)
73 {
74 char *errstr = "unknown";
75
76 switch (errno) {
77 case -EIO:
78 errstr = "IO failure";
79 break;
80 case -ENOMEM:
81 errstr = "Out of memory";
82 break;
83 case -EROFS:
84 errstr = "Readonly filesystem";
85 break;
86 case -EEXIST:
87 errstr = "Object already exists";
88 break;
89 case -ENOSPC:
90 errstr = "No space left";
91 break;
92 case -ENOENT:
93 errstr = "No such entry";
94 break;
95 }
96
97 return errstr;
98 }
99
100 /* btrfs handle error by forcing the filesystem readonly */
101 static void btrfs_handle_error(struct btrfs_fs_info *fs_info)
102 {
103 struct super_block *sb = fs_info->sb;
104
105 if (sb->s_flags & MS_RDONLY)
106 return;
107
108 if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
109 sb->s_flags |= MS_RDONLY;
110 btrfs_info(fs_info, "forced readonly");
111 /*
112 * Note that a running device replace operation is not
113 * canceled here although there is no way to update
114 * the progress. It would add the risk of a deadlock,
115 * therefore the canceling is omitted. The only penalty
116 * is that some I/O remains active until the procedure
117 * completes. The next time when the filesystem is
118 * mounted writeable again, the device replace
119 * operation continues.
120 */
121 }
122 }
123
124 /*
125 * __btrfs_handle_fs_error decodes expected errors from the caller and
126 * invokes the approciate error response.
127 */
128 __cold
129 void __btrfs_handle_fs_error(struct btrfs_fs_info *fs_info, const char *function,
130 unsigned int line, int errno, const char *fmt, ...)
131 {
132 struct super_block *sb = fs_info->sb;
133 #ifdef CONFIG_PRINTK
134 const char *errstr;
135 #endif
136
137 /*
138 * Special case: if the error is EROFS, and we're already
139 * under MS_RDONLY, then it is safe here.
140 */
141 if (errno == -EROFS && (sb->s_flags & MS_RDONLY))
142 return;
143
144 #ifdef CONFIG_PRINTK
145 errstr = btrfs_decode_error(errno);
146 if (fmt) {
147 struct va_format vaf;
148 va_list args;
149
150 va_start(args, fmt);
151 vaf.fmt = fmt;
152 vaf.va = &args;
153
154 pr_crit("BTRFS: error (device %s) in %s:%d: errno=%d %s (%pV)\n",
155 sb->s_id, function, line, errno, errstr, &vaf);
156 va_end(args);
157 } else {
158 pr_crit("BTRFS: error (device %s) in %s:%d: errno=%d %s\n",
159 sb->s_id, function, line, errno, errstr);
160 }
161 #endif
162
163 /*
164 * Today we only save the error info to memory. Long term we'll
165 * also send it down to the disk
166 */
167 set_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state);
168
169 /* Don't go through full error handling during mount */
170 if (sb->s_flags & MS_BORN)
171 btrfs_handle_error(fs_info);
172 }
173
174 #ifdef CONFIG_PRINTK
175 static const char * const logtypes[] = {
176 "emergency",
177 "alert",
178 "critical",
179 "error",
180 "warning",
181 "notice",
182 "info",
183 "debug",
184 };
185
186
187 /*
188 * Use one ratelimit state per log level so that a flood of less important
189 * messages doesn't cause more important ones to be dropped.
190 */
191 static struct ratelimit_state printk_limits[] = {
192 RATELIMIT_STATE_INIT(printk_limits[0], DEFAULT_RATELIMIT_INTERVAL, 100),
193 RATELIMIT_STATE_INIT(printk_limits[1], DEFAULT_RATELIMIT_INTERVAL, 100),
194 RATELIMIT_STATE_INIT(printk_limits[2], DEFAULT_RATELIMIT_INTERVAL, 100),
195 RATELIMIT_STATE_INIT(printk_limits[3], DEFAULT_RATELIMIT_INTERVAL, 100),
196 RATELIMIT_STATE_INIT(printk_limits[4], DEFAULT_RATELIMIT_INTERVAL, 100),
197 RATELIMIT_STATE_INIT(printk_limits[5], DEFAULT_RATELIMIT_INTERVAL, 100),
198 RATELIMIT_STATE_INIT(printk_limits[6], DEFAULT_RATELIMIT_INTERVAL, 100),
199 RATELIMIT_STATE_INIT(printk_limits[7], DEFAULT_RATELIMIT_INTERVAL, 100),
200 };
201
202 void btrfs_printk(const struct btrfs_fs_info *fs_info, const char *fmt, ...)
203 {
204 struct super_block *sb = fs_info->sb;
205 char lvl[PRINTK_MAX_SINGLE_HEADER_LEN + 1] = "\0";
206 struct va_format vaf;
207 va_list args;
208 int kern_level;
209 const char *type = logtypes[4];
210 struct ratelimit_state *ratelimit = &printk_limits[4];
211
212 va_start(args, fmt);
213
214 while ((kern_level = printk_get_level(fmt)) != 0) {
215 size_t size = printk_skip_level(fmt) - fmt;
216
217 if (kern_level >= '0' && kern_level <= '7') {
218 memcpy(lvl, fmt, size);
219 lvl[size] = '\0';
220 type = logtypes[kern_level - '0'];
221 ratelimit = &printk_limits[kern_level - '0'];
222 }
223 fmt += size;
224 }
225
226 vaf.fmt = fmt;
227 vaf.va = &args;
228
229 if (__ratelimit(ratelimit))
230 printk("%sBTRFS %s (device %s): %pV\n", lvl, type, sb->s_id, &vaf);
231
232 va_end(args);
233 }
234 #endif
235
236 /*
237 * We only mark the transaction aborted and then set the file system read-only.
238 * This will prevent new transactions from starting or trying to join this
239 * one.
240 *
241 * This means that error recovery at the call site is limited to freeing
242 * any local memory allocations and passing the error code up without
243 * further cleanup. The transaction should complete as it normally would
244 * in the call path but will return -EIO.
245 *
246 * We'll complete the cleanup in btrfs_end_transaction and
247 * btrfs_commit_transaction.
248 */
249 __cold
250 void __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
251 const char *function,
252 unsigned int line, int errno)
253 {
254 struct btrfs_fs_info *fs_info = trans->fs_info;
255
256 trans->aborted = errno;
257 /* Nothing used. The other threads that have joined this
258 * transaction may be able to continue. */
259 if (!trans->dirty && list_empty(&trans->new_bgs)) {
260 const char *errstr;
261
262 errstr = btrfs_decode_error(errno);
263 btrfs_warn(fs_info,
264 "%s:%d: Aborting unused transaction(%s).",
265 function, line, errstr);
266 return;
267 }
268 WRITE_ONCE(trans->transaction->aborted, errno);
269 /* Wake up anybody who may be waiting on this transaction */
270 wake_up(&fs_info->transaction_wait);
271 wake_up(&fs_info->transaction_blocked_wait);
272 __btrfs_handle_fs_error(fs_info, function, line, errno, NULL);
273 }
274 /*
275 * __btrfs_panic decodes unexpected, fatal errors from the caller,
276 * issues an alert, and either panics or BUGs, depending on mount options.
277 */
278 __cold
279 void __btrfs_panic(struct btrfs_fs_info *fs_info, const char *function,
280 unsigned int line, int errno, const char *fmt, ...)
281 {
282 char *s_id = "<unknown>";
283 const char *errstr;
284 struct va_format vaf = { .fmt = fmt };
285 va_list args;
286
287 if (fs_info)
288 s_id = fs_info->sb->s_id;
289
290 va_start(args, fmt);
291 vaf.va = &args;
292
293 errstr = btrfs_decode_error(errno);
294 if (fs_info && (fs_info->mount_opt & BTRFS_MOUNT_PANIC_ON_FATAL_ERROR))
295 panic(KERN_CRIT "BTRFS panic (device %s) in %s:%d: %pV (errno=%d %s)\n",
296 s_id, function, line, &vaf, errno, errstr);
297
298 btrfs_crit(fs_info, "panic in %s:%d: %pV (errno=%d %s)",
299 function, line, &vaf, errno, errstr);
300 va_end(args);
301 /* Caller calls BUG() */
302 }
303
304 static void btrfs_put_super(struct super_block *sb)
305 {
306 close_ctree(btrfs_sb(sb));
307 }
308
309 enum {
310 Opt_degraded, Opt_subvol, Opt_subvolid, Opt_device, Opt_nodatasum,
311 Opt_nodatacow, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd,
312 Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl, Opt_compress,
313 Opt_compress_type, Opt_compress_force, Opt_compress_force_type,
314 Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard,
315 Opt_space_cache, Opt_space_cache_version, Opt_clear_cache,
316 Opt_user_subvol_rm_allowed, Opt_enospc_debug, Opt_subvolrootid,
317 Opt_defrag, Opt_inode_cache, Opt_no_space_cache, Opt_recovery,
318 Opt_skip_balance, Opt_check_integrity,
319 Opt_check_integrity_including_extent_data,
320 Opt_check_integrity_print_mask, Opt_fatal_errors, Opt_rescan_uuid_tree,
321 Opt_commit_interval, Opt_barrier, Opt_nodefrag, Opt_nodiscard,
322 Opt_noenospc_debug, Opt_noflushoncommit, Opt_acl, Opt_datacow,
323 Opt_datasum, Opt_treelog, Opt_noinode_cache, Opt_usebackuproot,
324 Opt_nologreplay, Opt_norecovery,
325 #ifdef CONFIG_BTRFS_DEBUG
326 Opt_fragment_data, Opt_fragment_metadata, Opt_fragment_all,
327 #endif
328 Opt_err,
329 };
330
331 static const match_table_t tokens = {
332 {Opt_degraded, "degraded"},
333 {Opt_subvol, "subvol=%s"},
334 {Opt_subvolid, "subvolid=%s"},
335 {Opt_device, "device=%s"},
336 {Opt_nodatasum, "nodatasum"},
337 {Opt_datasum, "datasum"},
338 {Opt_nodatacow, "nodatacow"},
339 {Opt_datacow, "datacow"},
340 {Opt_nobarrier, "nobarrier"},
341 {Opt_barrier, "barrier"},
342 {Opt_max_inline, "max_inline=%s"},
343 {Opt_alloc_start, "alloc_start=%s"},
344 {Opt_thread_pool, "thread_pool=%d"},
345 {Opt_compress, "compress"},
346 {Opt_compress_type, "compress=%s"},
347 {Opt_compress_force, "compress-force"},
348 {Opt_compress_force_type, "compress-force=%s"},
349 {Opt_ssd, "ssd"},
350 {Opt_ssd_spread, "ssd_spread"},
351 {Opt_nossd, "nossd"},
352 {Opt_acl, "acl"},
353 {Opt_noacl, "noacl"},
354 {Opt_notreelog, "notreelog"},
355 {Opt_treelog, "treelog"},
356 {Opt_nologreplay, "nologreplay"},
357 {Opt_norecovery, "norecovery"},
358 {Opt_flushoncommit, "flushoncommit"},
359 {Opt_noflushoncommit, "noflushoncommit"},
360 {Opt_ratio, "metadata_ratio=%d"},
361 {Opt_discard, "discard"},
362 {Opt_nodiscard, "nodiscard"},
363 {Opt_space_cache, "space_cache"},
364 {Opt_space_cache_version, "space_cache=%s"},
365 {Opt_clear_cache, "clear_cache"},
366 {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
367 {Opt_enospc_debug, "enospc_debug"},
368 {Opt_noenospc_debug, "noenospc_debug"},
369 {Opt_subvolrootid, "subvolrootid=%d"},
370 {Opt_defrag, "autodefrag"},
371 {Opt_nodefrag, "noautodefrag"},
372 {Opt_inode_cache, "inode_cache"},
373 {Opt_noinode_cache, "noinode_cache"},
374 {Opt_no_space_cache, "nospace_cache"},
375 {Opt_recovery, "recovery"}, /* deprecated */
376 {Opt_usebackuproot, "usebackuproot"},
377 {Opt_skip_balance, "skip_balance"},
378 {Opt_check_integrity, "check_int"},
379 {Opt_check_integrity_including_extent_data, "check_int_data"},
380 {Opt_check_integrity_print_mask, "check_int_print_mask=%d"},
381 {Opt_rescan_uuid_tree, "rescan_uuid_tree"},
382 {Opt_fatal_errors, "fatal_errors=%s"},
383 {Opt_commit_interval, "commit=%d"},
384 #ifdef CONFIG_BTRFS_DEBUG
385 {Opt_fragment_data, "fragment=data"},
386 {Opt_fragment_metadata, "fragment=metadata"},
387 {Opt_fragment_all, "fragment=all"},
388 #endif
389 {Opt_err, NULL},
390 };
391
392 /*
393 * Regular mount options parser. Everything that is needed only when
394 * reading in a new superblock is parsed here.
395 * XXX JDM: This needs to be cleaned up for remount.
396 */
397 int btrfs_parse_options(struct btrfs_fs_info *info, char *options,
398 unsigned long new_flags)
399 {
400 substring_t args[MAX_OPT_ARGS];
401 char *p, *num, *orig = NULL;
402 u64 cache_gen;
403 int intarg;
404 int ret = 0;
405 char *compress_type;
406 bool compress_force = false;
407 enum btrfs_compression_type saved_compress_type;
408 bool saved_compress_force;
409 int no_compress = 0;
410
411 cache_gen = btrfs_super_cache_generation(info->super_copy);
412 if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE))
413 btrfs_set_opt(info->mount_opt, FREE_SPACE_TREE);
414 else if (cache_gen)
415 btrfs_set_opt(info->mount_opt, SPACE_CACHE);
416
417 /*
418 * Even the options are empty, we still need to do extra check
419 * against new flags
420 */
421 if (!options)
422 goto check;
423
424 /*
425 * strsep changes the string, duplicate it because parse_options
426 * gets called twice
427 */
428 options = kstrdup(options, GFP_NOFS);
429 if (!options)
430 return -ENOMEM;
431
432 orig = options;
433
434 while ((p = strsep(&options, ",")) != NULL) {
435 int token;
436 if (!*p)
437 continue;
438
439 token = match_token(p, tokens, args);
440 switch (token) {
441 case Opt_degraded:
442 btrfs_info(info, "allowing degraded mounts");
443 btrfs_set_opt(info->mount_opt, DEGRADED);
444 break;
445 case Opt_subvol:
446 case Opt_subvolid:
447 case Opt_subvolrootid:
448 case Opt_device:
449 /*
450 * These are parsed by btrfs_parse_early_options
451 * and can be happily ignored here.
452 */
453 break;
454 case Opt_nodatasum:
455 btrfs_set_and_info(info, NODATASUM,
456 "setting nodatasum");
457 break;
458 case Opt_datasum:
459 if (btrfs_test_opt(info, NODATASUM)) {
460 if (btrfs_test_opt(info, NODATACOW))
461 btrfs_info(info,
462 "setting datasum, datacow enabled");
463 else
464 btrfs_info(info, "setting datasum");
465 }
466 btrfs_clear_opt(info->mount_opt, NODATACOW);
467 btrfs_clear_opt(info->mount_opt, NODATASUM);
468 break;
469 case Opt_nodatacow:
470 if (!btrfs_test_opt(info, NODATACOW)) {
471 if (!btrfs_test_opt(info, COMPRESS) ||
472 !btrfs_test_opt(info, FORCE_COMPRESS)) {
473 btrfs_info(info,
474 "setting nodatacow, compression disabled");
475 } else {
476 btrfs_info(info, "setting nodatacow");
477 }
478 }
479 btrfs_clear_opt(info->mount_opt, COMPRESS);
480 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
481 btrfs_set_opt(info->mount_opt, NODATACOW);
482 btrfs_set_opt(info->mount_opt, NODATASUM);
483 break;
484 case Opt_datacow:
485 btrfs_clear_and_info(info, NODATACOW,
486 "setting datacow");
487 break;
488 case Opt_compress_force:
489 case Opt_compress_force_type:
490 compress_force = true;
491 /* Fallthrough */
492 case Opt_compress:
493 case Opt_compress_type:
494 saved_compress_type = btrfs_test_opt(info,
495 COMPRESS) ?
496 info->compress_type : BTRFS_COMPRESS_NONE;
497 saved_compress_force =
498 btrfs_test_opt(info, FORCE_COMPRESS);
499 if (token == Opt_compress ||
500 token == Opt_compress_force ||
501 strcmp(args[0].from, "zlib") == 0) {
502 compress_type = "zlib";
503 info->compress_type = BTRFS_COMPRESS_ZLIB;
504 btrfs_set_opt(info->mount_opt, COMPRESS);
505 btrfs_clear_opt(info->mount_opt, NODATACOW);
506 btrfs_clear_opt(info->mount_opt, NODATASUM);
507 no_compress = 0;
508 } else if (strcmp(args[0].from, "lzo") == 0) {
509 compress_type = "lzo";
510 info->compress_type = BTRFS_COMPRESS_LZO;
511 btrfs_set_opt(info->mount_opt, COMPRESS);
512 btrfs_clear_opt(info->mount_opt, NODATACOW);
513 btrfs_clear_opt(info->mount_opt, NODATASUM);
514 btrfs_set_fs_incompat(info, COMPRESS_LZO);
515 no_compress = 0;
516 } else if (strncmp(args[0].from, "no", 2) == 0) {
517 compress_type = "no";
518 btrfs_clear_opt(info->mount_opt, COMPRESS);
519 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
520 compress_force = false;
521 no_compress++;
522 } else {
523 ret = -EINVAL;
524 goto out;
525 }
526
527 if (compress_force) {
528 btrfs_set_opt(info->mount_opt, FORCE_COMPRESS);
529 } else {
530 /*
531 * If we remount from compress-force=xxx to
532 * compress=xxx, we need clear FORCE_COMPRESS
533 * flag, otherwise, there is no way for users
534 * to disable forcible compression separately.
535 */
536 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
537 }
538 if ((btrfs_test_opt(info, COMPRESS) &&
539 (info->compress_type != saved_compress_type ||
540 compress_force != saved_compress_force)) ||
541 (!btrfs_test_opt(info, COMPRESS) &&
542 no_compress == 1)) {
543 btrfs_info(info, "%s %s compression",
544 (compress_force) ? "force" : "use",
545 compress_type);
546 }
547 compress_force = false;
548 break;
549 case Opt_ssd:
550 btrfs_set_and_info(info, SSD,
551 "use ssd allocation scheme");
552 btrfs_clear_opt(info->mount_opt, NOSSD);
553 break;
554 case Opt_ssd_spread:
555 btrfs_set_and_info(info, SSD_SPREAD,
556 "use spread ssd allocation scheme");
557 btrfs_set_opt(info->mount_opt, SSD);
558 btrfs_clear_opt(info->mount_opt, NOSSD);
559 break;
560 case Opt_nossd:
561 btrfs_set_and_info(info, NOSSD,
562 "not using ssd allocation scheme");
563 btrfs_clear_opt(info->mount_opt, SSD);
564 btrfs_clear_opt(info->mount_opt, SSD_SPREAD);
565 break;
566 case Opt_barrier:
567 btrfs_clear_and_info(info, NOBARRIER,
568 "turning on barriers");
569 break;
570 case Opt_nobarrier:
571 btrfs_set_and_info(info, NOBARRIER,
572 "turning off barriers");
573 break;
574 case Opt_thread_pool:
575 ret = match_int(&args[0], &intarg);
576 if (ret) {
577 goto out;
578 } else if (intarg > 0) {
579 info->thread_pool_size = intarg;
580 } else {
581 ret = -EINVAL;
582 goto out;
583 }
584 break;
585 case Opt_max_inline:
586 num = match_strdup(&args[0]);
587 if (num) {
588 info->max_inline = memparse(num, NULL);
589 kfree(num);
590
591 if (info->max_inline) {
592 info->max_inline = min_t(u64,
593 info->max_inline,
594 info->sectorsize);
595 }
596 btrfs_info(info, "max_inline at %llu",
597 info->max_inline);
598 } else {
599 ret = -ENOMEM;
600 goto out;
601 }
602 break;
603 case Opt_alloc_start:
604 btrfs_info(info,
605 "option alloc_start is obsolete, ignored");
606 break;
607 case Opt_acl:
608 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
609 info->sb->s_flags |= MS_POSIXACL;
610 break;
611 #else
612 btrfs_err(info, "support for ACL not compiled in!");
613 ret = -EINVAL;
614 goto out;
615 #endif
616 case Opt_noacl:
617 info->sb->s_flags &= ~MS_POSIXACL;
618 break;
619 case Opt_notreelog:
620 btrfs_set_and_info(info, NOTREELOG,
621 "disabling tree log");
622 break;
623 case Opt_treelog:
624 btrfs_clear_and_info(info, NOTREELOG,
625 "enabling tree log");
626 break;
627 case Opt_norecovery:
628 case Opt_nologreplay:
629 btrfs_set_and_info(info, NOLOGREPLAY,
630 "disabling log replay at mount time");
631 break;
632 case Opt_flushoncommit:
633 btrfs_set_and_info(info, FLUSHONCOMMIT,
634 "turning on flush-on-commit");
635 break;
636 case Opt_noflushoncommit:
637 btrfs_clear_and_info(info, FLUSHONCOMMIT,
638 "turning off flush-on-commit");
639 break;
640 case Opt_ratio:
641 ret = match_int(&args[0], &intarg);
642 if (ret) {
643 goto out;
644 } else if (intarg >= 0) {
645 info->metadata_ratio = intarg;
646 btrfs_info(info, "metadata ratio %d",
647 info->metadata_ratio);
648 } else {
649 ret = -EINVAL;
650 goto out;
651 }
652 break;
653 case Opt_discard:
654 btrfs_set_and_info(info, DISCARD,
655 "turning on discard");
656 break;
657 case Opt_nodiscard:
658 btrfs_clear_and_info(info, DISCARD,
659 "turning off discard");
660 break;
661 case Opt_space_cache:
662 case Opt_space_cache_version:
663 if (token == Opt_space_cache ||
664 strcmp(args[0].from, "v1") == 0) {
665 btrfs_clear_opt(info->mount_opt,
666 FREE_SPACE_TREE);
667 btrfs_set_and_info(info, SPACE_CACHE,
668 "enabling disk space caching");
669 } else if (strcmp(args[0].from, "v2") == 0) {
670 btrfs_clear_opt(info->mount_opt,
671 SPACE_CACHE);
672 btrfs_set_and_info(info, FREE_SPACE_TREE,
673 "enabling free space tree");
674 } else {
675 ret = -EINVAL;
676 goto out;
677 }
678 break;
679 case Opt_rescan_uuid_tree:
680 btrfs_set_opt(info->mount_opt, RESCAN_UUID_TREE);
681 break;
682 case Opt_no_space_cache:
683 if (btrfs_test_opt(info, SPACE_CACHE)) {
684 btrfs_clear_and_info(info, SPACE_CACHE,
685 "disabling disk space caching");
686 }
687 if (btrfs_test_opt(info, FREE_SPACE_TREE)) {
688 btrfs_clear_and_info(info, FREE_SPACE_TREE,
689 "disabling free space tree");
690 }
691 break;
692 case Opt_inode_cache:
693 btrfs_set_pending_and_info(info, INODE_MAP_CACHE,
694 "enabling inode map caching");
695 break;
696 case Opt_noinode_cache:
697 btrfs_clear_pending_and_info(info, INODE_MAP_CACHE,
698 "disabling inode map caching");
699 break;
700 case Opt_clear_cache:
701 btrfs_set_and_info(info, CLEAR_CACHE,
702 "force clearing of disk cache");
703 break;
704 case Opt_user_subvol_rm_allowed:
705 btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
706 break;
707 case Opt_enospc_debug:
708 btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
709 break;
710 case Opt_noenospc_debug:
711 btrfs_clear_opt(info->mount_opt, ENOSPC_DEBUG);
712 break;
713 case Opt_defrag:
714 btrfs_set_and_info(info, AUTO_DEFRAG,
715 "enabling auto defrag");
716 break;
717 case Opt_nodefrag:
718 btrfs_clear_and_info(info, AUTO_DEFRAG,
719 "disabling auto defrag");
720 break;
721 case Opt_recovery:
722 btrfs_warn(info,
723 "'recovery' is deprecated, use 'usebackuproot' instead");
724 case Opt_usebackuproot:
725 btrfs_info(info,
726 "trying to use backup root at mount time");
727 btrfs_set_opt(info->mount_opt, USEBACKUPROOT);
728 break;
729 case Opt_skip_balance:
730 btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
731 break;
732 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
733 case Opt_check_integrity_including_extent_data:
734 btrfs_info(info,
735 "enabling check integrity including extent data");
736 btrfs_set_opt(info->mount_opt,
737 CHECK_INTEGRITY_INCLUDING_EXTENT_DATA);
738 btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
739 break;
740 case Opt_check_integrity:
741 btrfs_info(info, "enabling check integrity");
742 btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
743 break;
744 case Opt_check_integrity_print_mask:
745 ret = match_int(&args[0], &intarg);
746 if (ret) {
747 goto out;
748 } else if (intarg >= 0) {
749 info->check_integrity_print_mask = intarg;
750 btrfs_info(info,
751 "check_integrity_print_mask 0x%x",
752 info->check_integrity_print_mask);
753 } else {
754 ret = -EINVAL;
755 goto out;
756 }
757 break;
758 #else
759 case Opt_check_integrity_including_extent_data:
760 case Opt_check_integrity:
761 case Opt_check_integrity_print_mask:
762 btrfs_err(info,
763 "support for check_integrity* not compiled in!");
764 ret = -EINVAL;
765 goto out;
766 #endif
767 case Opt_fatal_errors:
768 if (strcmp(args[0].from, "panic") == 0)
769 btrfs_set_opt(info->mount_opt,
770 PANIC_ON_FATAL_ERROR);
771 else if (strcmp(args[0].from, "bug") == 0)
772 btrfs_clear_opt(info->mount_opt,
773 PANIC_ON_FATAL_ERROR);
774 else {
775 ret = -EINVAL;
776 goto out;
777 }
778 break;
779 case Opt_commit_interval:
780 intarg = 0;
781 ret = match_int(&args[0], &intarg);
782 if (ret < 0) {
783 btrfs_err(info, "invalid commit interval");
784 ret = -EINVAL;
785 goto out;
786 }
787 if (intarg > 0) {
788 if (intarg > 300) {
789 btrfs_warn(info,
790 "excessive commit interval %d",
791 intarg);
792 }
793 info->commit_interval = intarg;
794 } else {
795 btrfs_info(info,
796 "using default commit interval %ds",
797 BTRFS_DEFAULT_COMMIT_INTERVAL);
798 info->commit_interval = BTRFS_DEFAULT_COMMIT_INTERVAL;
799 }
800 break;
801 #ifdef CONFIG_BTRFS_DEBUG
802 case Opt_fragment_all:
803 btrfs_info(info, "fragmenting all space");
804 btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
805 btrfs_set_opt(info->mount_opt, FRAGMENT_METADATA);
806 break;
807 case Opt_fragment_metadata:
808 btrfs_info(info, "fragmenting metadata");
809 btrfs_set_opt(info->mount_opt,
810 FRAGMENT_METADATA);
811 break;
812 case Opt_fragment_data:
813 btrfs_info(info, "fragmenting data");
814 btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
815 break;
816 #endif
817 case Opt_err:
818 btrfs_info(info, "unrecognized mount option '%s'", p);
819 ret = -EINVAL;
820 goto out;
821 default:
822 break;
823 }
824 }
825 check:
826 /*
827 * Extra check for current option against current flag
828 */
829 if (btrfs_test_opt(info, NOLOGREPLAY) && !(new_flags & MS_RDONLY)) {
830 btrfs_err(info,
831 "nologreplay must be used with ro mount option");
832 ret = -EINVAL;
833 }
834 out:
835 if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE) &&
836 !btrfs_test_opt(info, FREE_SPACE_TREE) &&
837 !btrfs_test_opt(info, CLEAR_CACHE)) {
838 btrfs_err(info, "cannot disable free space tree");
839 ret = -EINVAL;
840
841 }
842 if (!ret && btrfs_test_opt(info, SPACE_CACHE))
843 btrfs_info(info, "disk space caching is enabled");
844 if (!ret && btrfs_test_opt(info, FREE_SPACE_TREE))
845 btrfs_info(info, "using free space tree");
846 kfree(orig);
847 return ret;
848 }
849
850 /*
851 * Parse mount options that are required early in the mount process.
852 *
853 * All other options will be parsed on much later in the mount process and
854 * only when we need to allocate a new super block.
855 */
856 static int btrfs_parse_early_options(const char *options, fmode_t flags,
857 void *holder, char **subvol_name, u64 *subvol_objectid,
858 struct btrfs_fs_devices **fs_devices)
859 {
860 substring_t args[MAX_OPT_ARGS];
861 char *device_name, *opts, *orig, *p;
862 char *num = NULL;
863 int error = 0;
864
865 if (!options)
866 return 0;
867
868 /*
869 * strsep changes the string, duplicate it because parse_options
870 * gets called twice
871 */
872 opts = kstrdup(options, GFP_KERNEL);
873 if (!opts)
874 return -ENOMEM;
875 orig = opts;
876
877 while ((p = strsep(&opts, ",")) != NULL) {
878 int token;
879 if (!*p)
880 continue;
881
882 token = match_token(p, tokens, args);
883 switch (token) {
884 case Opt_subvol:
885 kfree(*subvol_name);
886 *subvol_name = match_strdup(&args[0]);
887 if (!*subvol_name) {
888 error = -ENOMEM;
889 goto out;
890 }
891 break;
892 case Opt_subvolid:
893 num = match_strdup(&args[0]);
894 if (num) {
895 *subvol_objectid = memparse(num, NULL);
896 kfree(num);
897 /* we want the original fs_tree */
898 if (!*subvol_objectid)
899 *subvol_objectid =
900 BTRFS_FS_TREE_OBJECTID;
901 } else {
902 error = -EINVAL;
903 goto out;
904 }
905 break;
906 case Opt_subvolrootid:
907 pr_warn("BTRFS: 'subvolrootid' mount option is deprecated and has no effect\n");
908 break;
909 case Opt_device:
910 device_name = match_strdup(&args[0]);
911 if (!device_name) {
912 error = -ENOMEM;
913 goto out;
914 }
915 error = btrfs_scan_one_device(device_name,
916 flags, holder, fs_devices);
917 kfree(device_name);
918 if (error)
919 goto out;
920 break;
921 default:
922 break;
923 }
924 }
925
926 out:
927 kfree(orig);
928 return error;
929 }
930
931 static char *get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
932 u64 subvol_objectid)
933 {
934 struct btrfs_root *root = fs_info->tree_root;
935 struct btrfs_root *fs_root;
936 struct btrfs_root_ref *root_ref;
937 struct btrfs_inode_ref *inode_ref;
938 struct btrfs_key key;
939 struct btrfs_path *path = NULL;
940 char *name = NULL, *ptr;
941 u64 dirid;
942 int len;
943 int ret;
944
945 path = btrfs_alloc_path();
946 if (!path) {
947 ret = -ENOMEM;
948 goto err;
949 }
950 path->leave_spinning = 1;
951
952 name = kmalloc(PATH_MAX, GFP_NOFS);
953 if (!name) {
954 ret = -ENOMEM;
955 goto err;
956 }
957 ptr = name + PATH_MAX - 1;
958 ptr[0] = '\0';
959
960 /*
961 * Walk up the subvolume trees in the tree of tree roots by root
962 * backrefs until we hit the top-level subvolume.
963 */
964 while (subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
965 key.objectid = subvol_objectid;
966 key.type = BTRFS_ROOT_BACKREF_KEY;
967 key.offset = (u64)-1;
968
969 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
970 if (ret < 0) {
971 goto err;
972 } else if (ret > 0) {
973 ret = btrfs_previous_item(root, path, subvol_objectid,
974 BTRFS_ROOT_BACKREF_KEY);
975 if (ret < 0) {
976 goto err;
977 } else if (ret > 0) {
978 ret = -ENOENT;
979 goto err;
980 }
981 }
982
983 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
984 subvol_objectid = key.offset;
985
986 root_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
987 struct btrfs_root_ref);
988 len = btrfs_root_ref_name_len(path->nodes[0], root_ref);
989 ptr -= len + 1;
990 if (ptr < name) {
991 ret = -ENAMETOOLONG;
992 goto err;
993 }
994 read_extent_buffer(path->nodes[0], ptr + 1,
995 (unsigned long)(root_ref + 1), len);
996 ptr[0] = '/';
997 dirid = btrfs_root_ref_dirid(path->nodes[0], root_ref);
998 btrfs_release_path(path);
999
1000 key.objectid = subvol_objectid;
1001 key.type = BTRFS_ROOT_ITEM_KEY;
1002 key.offset = (u64)-1;
1003 fs_root = btrfs_read_fs_root_no_name(fs_info, &key);
1004 if (IS_ERR(fs_root)) {
1005 ret = PTR_ERR(fs_root);
1006 goto err;
1007 }
1008
1009 /*
1010 * Walk up the filesystem tree by inode refs until we hit the
1011 * root directory.
1012 */
1013 while (dirid != BTRFS_FIRST_FREE_OBJECTID) {
1014 key.objectid = dirid;
1015 key.type = BTRFS_INODE_REF_KEY;
1016 key.offset = (u64)-1;
1017
1018 ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0);
1019 if (ret < 0) {
1020 goto err;
1021 } else if (ret > 0) {
1022 ret = btrfs_previous_item(fs_root, path, dirid,
1023 BTRFS_INODE_REF_KEY);
1024 if (ret < 0) {
1025 goto err;
1026 } else if (ret > 0) {
1027 ret = -ENOENT;
1028 goto err;
1029 }
1030 }
1031
1032 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1033 dirid = key.offset;
1034
1035 inode_ref = btrfs_item_ptr(path->nodes[0],
1036 path->slots[0],
1037 struct btrfs_inode_ref);
1038 len = btrfs_inode_ref_name_len(path->nodes[0],
1039 inode_ref);
1040 ptr -= len + 1;
1041 if (ptr < name) {
1042 ret = -ENAMETOOLONG;
1043 goto err;
1044 }
1045 read_extent_buffer(path->nodes[0], ptr + 1,
1046 (unsigned long)(inode_ref + 1), len);
1047 ptr[0] = '/';
1048 btrfs_release_path(path);
1049 }
1050 }
1051
1052 btrfs_free_path(path);
1053 if (ptr == name + PATH_MAX - 1) {
1054 name[0] = '/';
1055 name[1] = '\0';
1056 } else {
1057 memmove(name, ptr, name + PATH_MAX - ptr);
1058 }
1059 return name;
1060
1061 err:
1062 btrfs_free_path(path);
1063 kfree(name);
1064 return ERR_PTR(ret);
1065 }
1066
1067 static int get_default_subvol_objectid(struct btrfs_fs_info *fs_info, u64 *objectid)
1068 {
1069 struct btrfs_root *root = fs_info->tree_root;
1070 struct btrfs_dir_item *di;
1071 struct btrfs_path *path;
1072 struct btrfs_key location;
1073 u64 dir_id;
1074
1075 path = btrfs_alloc_path();
1076 if (!path)
1077 return -ENOMEM;
1078 path->leave_spinning = 1;
1079
1080 /*
1081 * Find the "default" dir item which points to the root item that we
1082 * will mount by default if we haven't been given a specific subvolume
1083 * to mount.
1084 */
1085 dir_id = btrfs_super_root_dir(fs_info->super_copy);
1086 di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
1087 if (IS_ERR(di)) {
1088 btrfs_free_path(path);
1089 return PTR_ERR(di);
1090 }
1091 if (!di) {
1092 /*
1093 * Ok the default dir item isn't there. This is weird since
1094 * it's always been there, but don't freak out, just try and
1095 * mount the top-level subvolume.
1096 */
1097 btrfs_free_path(path);
1098 *objectid = BTRFS_FS_TREE_OBJECTID;
1099 return 0;
1100 }
1101
1102 btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
1103 btrfs_free_path(path);
1104 *objectid = location.objectid;
1105 return 0;
1106 }
1107
1108 static int btrfs_fill_super(struct super_block *sb,
1109 struct btrfs_fs_devices *fs_devices,
1110 void *data)
1111 {
1112 struct inode *inode;
1113 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1114 struct btrfs_key key;
1115 int err;
1116
1117 sb->s_maxbytes = MAX_LFS_FILESIZE;
1118 sb->s_magic = BTRFS_SUPER_MAGIC;
1119 sb->s_op = &btrfs_super_ops;
1120 sb->s_d_op = &btrfs_dentry_operations;
1121 sb->s_export_op = &btrfs_export_ops;
1122 sb->s_xattr = btrfs_xattr_handlers;
1123 sb->s_time_gran = 1;
1124 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
1125 sb->s_flags |= MS_POSIXACL;
1126 #endif
1127 sb->s_flags |= MS_I_VERSION;
1128 sb->s_iflags |= SB_I_CGROUPWB;
1129
1130 err = super_setup_bdi(sb);
1131 if (err) {
1132 btrfs_err(fs_info, "super_setup_bdi failed");
1133 return err;
1134 }
1135
1136 err = open_ctree(sb, fs_devices, (char *)data);
1137 if (err) {
1138 btrfs_err(fs_info, "open_ctree failed");
1139 return err;
1140 }
1141
1142 key.objectid = BTRFS_FIRST_FREE_OBJECTID;
1143 key.type = BTRFS_INODE_ITEM_KEY;
1144 key.offset = 0;
1145 inode = btrfs_iget(sb, &key, fs_info->fs_root, NULL);
1146 if (IS_ERR(inode)) {
1147 err = PTR_ERR(inode);
1148 goto fail_close;
1149 }
1150
1151 sb->s_root = d_make_root(inode);
1152 if (!sb->s_root) {
1153 err = -ENOMEM;
1154 goto fail_close;
1155 }
1156
1157 cleancache_init_fs(sb);
1158 sb->s_flags |= MS_ACTIVE;
1159 return 0;
1160
1161 fail_close:
1162 close_ctree(fs_info);
1163 return err;
1164 }
1165
1166 int btrfs_sync_fs(struct super_block *sb, int wait)
1167 {
1168 struct btrfs_trans_handle *trans;
1169 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1170 struct btrfs_root *root = fs_info->tree_root;
1171
1172 trace_btrfs_sync_fs(fs_info, wait);
1173
1174 if (!wait) {
1175 filemap_flush(fs_info->btree_inode->i_mapping);
1176 return 0;
1177 }
1178
1179 btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
1180
1181 trans = btrfs_attach_transaction_barrier(root);
1182 if (IS_ERR(trans)) {
1183 /* no transaction, don't bother */
1184 if (PTR_ERR(trans) == -ENOENT) {
1185 /*
1186 * Exit unless we have some pending changes
1187 * that need to go through commit
1188 */
1189 if (fs_info->pending_changes == 0)
1190 return 0;
1191 /*
1192 * A non-blocking test if the fs is frozen. We must not
1193 * start a new transaction here otherwise a deadlock
1194 * happens. The pending operations are delayed to the
1195 * next commit after thawing.
1196 */
1197 if (__sb_start_write(sb, SB_FREEZE_WRITE, false))
1198 __sb_end_write(sb, SB_FREEZE_WRITE);
1199 else
1200 return 0;
1201 trans = btrfs_start_transaction(root, 0);
1202 }
1203 if (IS_ERR(trans))
1204 return PTR_ERR(trans);
1205 }
1206 return btrfs_commit_transaction(trans);
1207 }
1208
1209 static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
1210 {
1211 struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
1212 char *compress_type;
1213
1214 if (btrfs_test_opt(info, DEGRADED))
1215 seq_puts(seq, ",degraded");
1216 if (btrfs_test_opt(info, NODATASUM))
1217 seq_puts(seq, ",nodatasum");
1218 if (btrfs_test_opt(info, NODATACOW))
1219 seq_puts(seq, ",nodatacow");
1220 if (btrfs_test_opt(info, NOBARRIER))
1221 seq_puts(seq, ",nobarrier");
1222 if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE)
1223 seq_printf(seq, ",max_inline=%llu", info->max_inline);
1224 if (info->thread_pool_size != min_t(unsigned long,
1225 num_online_cpus() + 2, 8))
1226 seq_printf(seq, ",thread_pool=%d", info->thread_pool_size);
1227 if (btrfs_test_opt(info, COMPRESS)) {
1228 if (info->compress_type == BTRFS_COMPRESS_ZLIB)
1229 compress_type = "zlib";
1230 else
1231 compress_type = "lzo";
1232 if (btrfs_test_opt(info, FORCE_COMPRESS))
1233 seq_printf(seq, ",compress-force=%s", compress_type);
1234 else
1235 seq_printf(seq, ",compress=%s", compress_type);
1236 }
1237 if (btrfs_test_opt(info, NOSSD))
1238 seq_puts(seq, ",nossd");
1239 if (btrfs_test_opt(info, SSD_SPREAD))
1240 seq_puts(seq, ",ssd_spread");
1241 else if (btrfs_test_opt(info, SSD))
1242 seq_puts(seq, ",ssd");
1243 if (btrfs_test_opt(info, NOTREELOG))
1244 seq_puts(seq, ",notreelog");
1245 if (btrfs_test_opt(info, NOLOGREPLAY))
1246 seq_puts(seq, ",nologreplay");
1247 if (btrfs_test_opt(info, FLUSHONCOMMIT))
1248 seq_puts(seq, ",flushoncommit");
1249 if (btrfs_test_opt(info, DISCARD))
1250 seq_puts(seq, ",discard");
1251 if (!(info->sb->s_flags & MS_POSIXACL))
1252 seq_puts(seq, ",noacl");
1253 if (btrfs_test_opt(info, SPACE_CACHE))
1254 seq_puts(seq, ",space_cache");
1255 else if (btrfs_test_opt(info, FREE_SPACE_TREE))
1256 seq_puts(seq, ",space_cache=v2");
1257 else
1258 seq_puts(seq, ",nospace_cache");
1259 if (btrfs_test_opt(info, RESCAN_UUID_TREE))
1260 seq_puts(seq, ",rescan_uuid_tree");
1261 if (btrfs_test_opt(info, CLEAR_CACHE))
1262 seq_puts(seq, ",clear_cache");
1263 if (btrfs_test_opt(info, USER_SUBVOL_RM_ALLOWED))
1264 seq_puts(seq, ",user_subvol_rm_allowed");
1265 if (btrfs_test_opt(info, ENOSPC_DEBUG))
1266 seq_puts(seq, ",enospc_debug");
1267 if (btrfs_test_opt(info, AUTO_DEFRAG))
1268 seq_puts(seq, ",autodefrag");
1269 if (btrfs_test_opt(info, INODE_MAP_CACHE))
1270 seq_puts(seq, ",inode_cache");
1271 if (btrfs_test_opt(info, SKIP_BALANCE))
1272 seq_puts(seq, ",skip_balance");
1273 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
1274 if (btrfs_test_opt(info, CHECK_INTEGRITY_INCLUDING_EXTENT_DATA))
1275 seq_puts(seq, ",check_int_data");
1276 else if (btrfs_test_opt(info, CHECK_INTEGRITY))
1277 seq_puts(seq, ",check_int");
1278 if (info->check_integrity_print_mask)
1279 seq_printf(seq, ",check_int_print_mask=%d",
1280 info->check_integrity_print_mask);
1281 #endif
1282 if (info->metadata_ratio)
1283 seq_printf(seq, ",metadata_ratio=%d",
1284 info->metadata_ratio);
1285 if (btrfs_test_opt(info, PANIC_ON_FATAL_ERROR))
1286 seq_puts(seq, ",fatal_errors=panic");
1287 if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL)
1288 seq_printf(seq, ",commit=%d", info->commit_interval);
1289 #ifdef CONFIG_BTRFS_DEBUG
1290 if (btrfs_test_opt(info, FRAGMENT_DATA))
1291 seq_puts(seq, ",fragment=data");
1292 if (btrfs_test_opt(info, FRAGMENT_METADATA))
1293 seq_puts(seq, ",fragment=metadata");
1294 #endif
1295 seq_printf(seq, ",subvolid=%llu",
1296 BTRFS_I(d_inode(dentry))->root->root_key.objectid);
1297 seq_puts(seq, ",subvol=");
1298 seq_dentry(seq, dentry, " \t\n\\");
1299 return 0;
1300 }
1301
1302 static int btrfs_test_super(struct super_block *s, void *data)
1303 {
1304 struct btrfs_fs_info *p = data;
1305 struct btrfs_fs_info *fs_info = btrfs_sb(s);
1306
1307 return fs_info->fs_devices == p->fs_devices;
1308 }
1309
1310 static int btrfs_set_super(struct super_block *s, void *data)
1311 {
1312 int err = set_anon_super(s, data);
1313 if (!err)
1314 s->s_fs_info = data;
1315 return err;
1316 }
1317
1318 /*
1319 * subvolumes are identified by ino 256
1320 */
1321 static inline int is_subvolume_inode(struct inode *inode)
1322 {
1323 if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
1324 return 1;
1325 return 0;
1326 }
1327
1328 /*
1329 * This will add subvolid=0 to the argument string while removing any subvol=
1330 * and subvolid= arguments to make sure we get the top-level root for path
1331 * walking to the subvol we want.
1332 */
1333 static char *setup_root_args(char *args)
1334 {
1335 char *buf, *dst, *sep;
1336
1337 if (!args)
1338 return kstrdup("subvolid=0", GFP_NOFS);
1339
1340 /* The worst case is that we add ",subvolid=0" to the end. */
1341 buf = dst = kmalloc(strlen(args) + strlen(",subvolid=0") + 1, GFP_NOFS);
1342 if (!buf)
1343 return NULL;
1344
1345 while (1) {
1346 sep = strchrnul(args, ',');
1347 if (!strstarts(args, "subvol=") &&
1348 !strstarts(args, "subvolid=")) {
1349 memcpy(dst, args, sep - args);
1350 dst += sep - args;
1351 *dst++ = ',';
1352 }
1353 if (*sep)
1354 args = sep + 1;
1355 else
1356 break;
1357 }
1358 strcpy(dst, "subvolid=0");
1359
1360 return buf;
1361 }
1362
1363 static struct dentry *mount_subvol(const char *subvol_name, u64 subvol_objectid,
1364 int flags, const char *device_name,
1365 char *data)
1366 {
1367 struct dentry *root;
1368 struct vfsmount *mnt = NULL;
1369 char *newargs;
1370 int ret;
1371
1372 newargs = setup_root_args(data);
1373 if (!newargs) {
1374 root = ERR_PTR(-ENOMEM);
1375 goto out;
1376 }
1377
1378 mnt = vfs_kern_mount(&btrfs_fs_type, flags, device_name, newargs);
1379 if (PTR_ERR_OR_ZERO(mnt) == -EBUSY) {
1380 if (flags & MS_RDONLY) {
1381 mnt = vfs_kern_mount(&btrfs_fs_type, flags & ~MS_RDONLY,
1382 device_name, newargs);
1383 } else {
1384 mnt = vfs_kern_mount(&btrfs_fs_type, flags | MS_RDONLY,
1385 device_name, newargs);
1386 if (IS_ERR(mnt)) {
1387 root = ERR_CAST(mnt);
1388 mnt = NULL;
1389 goto out;
1390 }
1391
1392 down_write(&mnt->mnt_sb->s_umount);
1393 ret = btrfs_remount(mnt->mnt_sb, &flags, NULL);
1394 up_write(&mnt->mnt_sb->s_umount);
1395 if (ret < 0) {
1396 root = ERR_PTR(ret);
1397 goto out;
1398 }
1399 }
1400 }
1401 if (IS_ERR(mnt)) {
1402 root = ERR_CAST(mnt);
1403 mnt = NULL;
1404 goto out;
1405 }
1406
1407 if (!subvol_name) {
1408 if (!subvol_objectid) {
1409 ret = get_default_subvol_objectid(btrfs_sb(mnt->mnt_sb),
1410 &subvol_objectid);
1411 if (ret) {
1412 root = ERR_PTR(ret);
1413 goto out;
1414 }
1415 }
1416 subvol_name = get_subvol_name_from_objectid(btrfs_sb(mnt->mnt_sb),
1417 subvol_objectid);
1418 if (IS_ERR(subvol_name)) {
1419 root = ERR_CAST(subvol_name);
1420 subvol_name = NULL;
1421 goto out;
1422 }
1423
1424 }
1425
1426 root = mount_subtree(mnt, subvol_name);
1427 /* mount_subtree() drops our reference on the vfsmount. */
1428 mnt = NULL;
1429
1430 if (!IS_ERR(root)) {
1431 struct super_block *s = root->d_sb;
1432 struct btrfs_fs_info *fs_info = btrfs_sb(s);
1433 struct inode *root_inode = d_inode(root);
1434 u64 root_objectid = BTRFS_I(root_inode)->root->root_key.objectid;
1435
1436 ret = 0;
1437 if (!is_subvolume_inode(root_inode)) {
1438 btrfs_err(fs_info, "'%s' is not a valid subvolume",
1439 subvol_name);
1440 ret = -EINVAL;
1441 }
1442 if (subvol_objectid && root_objectid != subvol_objectid) {
1443 /*
1444 * This will also catch a race condition where a
1445 * subvolume which was passed by ID is renamed and
1446 * another subvolume is renamed over the old location.
1447 */
1448 btrfs_err(fs_info,
1449 "subvol '%s' does not match subvolid %llu",
1450 subvol_name, subvol_objectid);
1451 ret = -EINVAL;
1452 }
1453 if (ret) {
1454 dput(root);
1455 root = ERR_PTR(ret);
1456 deactivate_locked_super(s);
1457 }
1458 }
1459
1460 out:
1461 mntput(mnt);
1462 kfree(newargs);
1463 kfree(subvol_name);
1464 return root;
1465 }
1466
1467 static int parse_security_options(char *orig_opts,
1468 struct security_mnt_opts *sec_opts)
1469 {
1470 char *secdata = NULL;
1471 int ret = 0;
1472
1473 secdata = alloc_secdata();
1474 if (!secdata)
1475 return -ENOMEM;
1476 ret = security_sb_copy_data(orig_opts, secdata);
1477 if (ret) {
1478 free_secdata(secdata);
1479 return ret;
1480 }
1481 ret = security_sb_parse_opts_str(secdata, sec_opts);
1482 free_secdata(secdata);
1483 return ret;
1484 }
1485
1486 static int setup_security_options(struct btrfs_fs_info *fs_info,
1487 struct super_block *sb,
1488 struct security_mnt_opts *sec_opts)
1489 {
1490 int ret = 0;
1491
1492 /*
1493 * Call security_sb_set_mnt_opts() to check whether new sec_opts
1494 * is valid.
1495 */
1496 ret = security_sb_set_mnt_opts(sb, sec_opts, 0, NULL);
1497 if (ret)
1498 return ret;
1499
1500 #ifdef CONFIG_SECURITY
1501 if (!fs_info->security_opts.num_mnt_opts) {
1502 /* first time security setup, copy sec_opts to fs_info */
1503 memcpy(&fs_info->security_opts, sec_opts, sizeof(*sec_opts));
1504 } else {
1505 /*
1506 * Since SELinux (the only one supporting security_mnt_opts)
1507 * does NOT support changing context during remount/mount of
1508 * the same sb, this must be the same or part of the same
1509 * security options, just free it.
1510 */
1511 security_free_mnt_opts(sec_opts);
1512 }
1513 #endif
1514 return ret;
1515 }
1516
1517 /*
1518 * Find a superblock for the given device / mount point.
1519 *
1520 * Note: This is based on get_sb_bdev from fs/super.c with a few additions
1521 * for multiple device setup. Make sure to keep it in sync.
1522 */
1523 static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
1524 const char *device_name, void *data)
1525 {
1526 struct block_device *bdev = NULL;
1527 struct super_block *s;
1528 struct btrfs_fs_devices *fs_devices = NULL;
1529 struct btrfs_fs_info *fs_info = NULL;
1530 struct security_mnt_opts new_sec_opts;
1531 fmode_t mode = FMODE_READ;
1532 char *subvol_name = NULL;
1533 u64 subvol_objectid = 0;
1534 int error = 0;
1535
1536 if (!(flags & MS_RDONLY))
1537 mode |= FMODE_WRITE;
1538
1539 error = btrfs_parse_early_options(data, mode, fs_type,
1540 &subvol_name, &subvol_objectid,
1541 &fs_devices);
1542 if (error) {
1543 kfree(subvol_name);
1544 return ERR_PTR(error);
1545 }
1546
1547 if (subvol_name || subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
1548 /* mount_subvol() will free subvol_name. */
1549 return mount_subvol(subvol_name, subvol_objectid, flags,
1550 device_name, data);
1551 }
1552
1553 security_init_mnt_opts(&new_sec_opts);
1554 if (data) {
1555 error = parse_security_options(data, &new_sec_opts);
1556 if (error)
1557 return ERR_PTR(error);
1558 }
1559
1560 error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices);
1561 if (error)
1562 goto error_sec_opts;
1563
1564 /*
1565 * Setup a dummy root and fs_info for test/set super. This is because
1566 * we don't actually fill this stuff out until open_ctree, but we need
1567 * it for searching for existing supers, so this lets us do that and
1568 * then open_ctree will properly initialize everything later.
1569 */
1570 fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_NOFS);
1571 if (!fs_info) {
1572 error = -ENOMEM;
1573 goto error_sec_opts;
1574 }
1575
1576 fs_info->fs_devices = fs_devices;
1577
1578 fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
1579 fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
1580 security_init_mnt_opts(&fs_info->security_opts);
1581 if (!fs_info->super_copy || !fs_info->super_for_commit) {
1582 error = -ENOMEM;
1583 goto error_fs_info;
1584 }
1585
1586 error = btrfs_open_devices(fs_devices, mode, fs_type);
1587 if (error)
1588 goto error_fs_info;
1589
1590 if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
1591 error = -EACCES;
1592 goto error_close_devices;
1593 }
1594
1595 bdev = fs_devices->latest_bdev;
1596 s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | MS_NOSEC,
1597 fs_info);
1598 if (IS_ERR(s)) {
1599 error = PTR_ERR(s);
1600 goto error_close_devices;
1601 }
1602
1603 if (s->s_root) {
1604 btrfs_close_devices(fs_devices);
1605 free_fs_info(fs_info);
1606 if ((flags ^ s->s_flags) & MS_RDONLY)
1607 error = -EBUSY;
1608 } else {
1609 snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev);
1610 btrfs_sb(s)->bdev_holder = fs_type;
1611 error = btrfs_fill_super(s, fs_devices, data);
1612 }
1613 if (error) {
1614 deactivate_locked_super(s);
1615 goto error_sec_opts;
1616 }
1617
1618 fs_info = btrfs_sb(s);
1619 error = setup_security_options(fs_info, s, &new_sec_opts);
1620 if (error) {
1621 deactivate_locked_super(s);
1622 goto error_sec_opts;
1623 }
1624
1625 return dget(s->s_root);
1626
1627 error_close_devices:
1628 btrfs_close_devices(fs_devices);
1629 error_fs_info:
1630 free_fs_info(fs_info);
1631 error_sec_opts:
1632 security_free_mnt_opts(&new_sec_opts);
1633 return ERR_PTR(error);
1634 }
1635
1636 static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
1637 int new_pool_size, int old_pool_size)
1638 {
1639 if (new_pool_size == old_pool_size)
1640 return;
1641
1642 fs_info->thread_pool_size = new_pool_size;
1643
1644 btrfs_info(fs_info, "resize thread pool %d -> %d",
1645 old_pool_size, new_pool_size);
1646
1647 btrfs_workqueue_set_max(fs_info->workers, new_pool_size);
1648 btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size);
1649 btrfs_workqueue_set_max(fs_info->submit_workers, new_pool_size);
1650 btrfs_workqueue_set_max(fs_info->caching_workers, new_pool_size);
1651 btrfs_workqueue_set_max(fs_info->endio_workers, new_pool_size);
1652 btrfs_workqueue_set_max(fs_info->endio_meta_workers, new_pool_size);
1653 btrfs_workqueue_set_max(fs_info->endio_meta_write_workers,
1654 new_pool_size);
1655 btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size);
1656 btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
1657 btrfs_workqueue_set_max(fs_info->delayed_workers, new_pool_size);
1658 btrfs_workqueue_set_max(fs_info->readahead_workers, new_pool_size);
1659 btrfs_workqueue_set_max(fs_info->scrub_wr_completion_workers,
1660 new_pool_size);
1661 }
1662
1663 static inline void btrfs_remount_prepare(struct btrfs_fs_info *fs_info)
1664 {
1665 set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1666 }
1667
1668 static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info,
1669 unsigned long old_opts, int flags)
1670 {
1671 if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1672 (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1673 (flags & MS_RDONLY))) {
1674 /* wait for any defraggers to finish */
1675 wait_event(fs_info->transaction_wait,
1676 (atomic_read(&fs_info->defrag_running) == 0));
1677 if (flags & MS_RDONLY)
1678 sync_filesystem(fs_info->sb);
1679 }
1680 }
1681
1682 static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
1683 unsigned long old_opts)
1684 {
1685 /*
1686 * We need to cleanup all defragable inodes if the autodefragment is
1687 * close or the filesystem is read only.
1688 */
1689 if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1690 (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1691 (fs_info->sb->s_flags & MS_RDONLY))) {
1692 btrfs_cleanup_defrag_inodes(fs_info);
1693 }
1694
1695 clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1696 }
1697
1698 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
1699 {
1700 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1701 struct btrfs_root *root = fs_info->tree_root;
1702 unsigned old_flags = sb->s_flags;
1703 unsigned long old_opts = fs_info->mount_opt;
1704 unsigned long old_compress_type = fs_info->compress_type;
1705 u64 old_max_inline = fs_info->max_inline;
1706 int old_thread_pool_size = fs_info->thread_pool_size;
1707 unsigned int old_metadata_ratio = fs_info->metadata_ratio;
1708 int ret;
1709
1710 sync_filesystem(sb);
1711 btrfs_remount_prepare(fs_info);
1712
1713 if (data) {
1714 struct security_mnt_opts new_sec_opts;
1715
1716 security_init_mnt_opts(&new_sec_opts);
1717 ret = parse_security_options(data, &new_sec_opts);
1718 if (ret)
1719 goto restore;
1720 ret = setup_security_options(fs_info, sb,
1721 &new_sec_opts);
1722 if (ret) {
1723 security_free_mnt_opts(&new_sec_opts);
1724 goto restore;
1725 }
1726 }
1727
1728 ret = btrfs_parse_options(fs_info, data, *flags);
1729 if (ret) {
1730 ret = -EINVAL;
1731 goto restore;
1732 }
1733
1734 btrfs_remount_begin(fs_info, old_opts, *flags);
1735 btrfs_resize_thread_pool(fs_info,
1736 fs_info->thread_pool_size, old_thread_pool_size);
1737
1738 if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1739 goto out;
1740
1741 if (*flags & MS_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
1748 /* wait for the uuid_scan task to finish */
1749 down(&fs_info->uuid_tree_rescan_sem);
1750 /* avoid complains from lockdep et al. */
1751 up(&fs_info->uuid_tree_rescan_sem);
1752
1753 sb->s_flags |= MS_RDONLY;
1754
1755 /*
1756 * Setting MS_RDONLY will put the cleaner thread to
1757 * sleep at the next loop if it's already active.
1758 * If it's already asleep, we'll leave unused block
1759 * groups on disk until we're mounted read-write again
1760 * unless we clean them up here.
1761 */
1762 btrfs_delete_unused_bgs(fs_info);
1763
1764 btrfs_dev_replace_suspend_for_unmount(fs_info);
1765 btrfs_scrub_cancel(fs_info);
1766 btrfs_pause_balance(fs_info);
1767
1768 ret = btrfs_commit_super(fs_info);
1769 if (ret)
1770 goto restore;
1771 } else {
1772 if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
1773 btrfs_err(fs_info,
1774 "Remounting read-write after error is not allowed");
1775 ret = -EINVAL;
1776 goto restore;
1777 }
1778 if (fs_info->fs_devices->rw_devices == 0) {
1779 ret = -EACCES;
1780 goto restore;
1781 }
1782
1783 if (fs_info->fs_devices->missing_devices >
1784 fs_info->num_tolerated_disk_barrier_failures) {
1785 btrfs_warn(fs_info,
1786 "too many missing devices, writeable remount is not allowed");
1787 ret = -EACCES;
1788 goto restore;
1789 }
1790
1791 if (btrfs_super_log_root(fs_info->super_copy) != 0) {
1792 ret = -EINVAL;
1793 goto restore;
1794 }
1795
1796 ret = btrfs_cleanup_fs_roots(fs_info);
1797 if (ret)
1798 goto restore;
1799
1800 /* recover relocation */
1801 mutex_lock(&fs_info->cleaner_mutex);
1802 ret = btrfs_recover_relocation(root);
1803 mutex_unlock(&fs_info->cleaner_mutex);
1804 if (ret)
1805 goto restore;
1806
1807 ret = btrfs_resume_balance_async(fs_info);
1808 if (ret)
1809 goto restore;
1810
1811 ret = btrfs_resume_dev_replace_async(fs_info);
1812 if (ret) {
1813 btrfs_warn(fs_info, "failed to resume dev_replace");
1814 goto restore;
1815 }
1816
1817 if (!fs_info->uuid_root) {
1818 btrfs_info(fs_info, "creating UUID tree");
1819 ret = btrfs_create_uuid_tree(fs_info);
1820 if (ret) {
1821 btrfs_warn(fs_info,
1822 "failed to create the UUID tree %d",
1823 ret);
1824 goto restore;
1825 }
1826 }
1827 sb->s_flags &= ~MS_RDONLY;
1828
1829 set_bit(BTRFS_FS_OPEN, &fs_info->flags);
1830 }
1831 out:
1832 wake_up_process(fs_info->transaction_kthread);
1833 btrfs_remount_cleanup(fs_info, old_opts);
1834 return 0;
1835
1836 restore:
1837 /* We've hit an error - don't reset MS_RDONLY */
1838 if (sb->s_flags & MS_RDONLY)
1839 old_flags |= MS_RDONLY;
1840 sb->s_flags = old_flags;
1841 fs_info->mount_opt = old_opts;
1842 fs_info->compress_type = old_compress_type;
1843 fs_info->max_inline = old_max_inline;
1844 btrfs_resize_thread_pool(fs_info,
1845 old_thread_pool_size, fs_info->thread_pool_size);
1846 fs_info->metadata_ratio = old_metadata_ratio;
1847 btrfs_remount_cleanup(fs_info, old_opts);
1848 return ret;
1849 }
1850
1851 /* Used to sort the devices by max_avail(descending sort) */
1852 static int btrfs_cmp_device_free_bytes(const void *dev_info1,
1853 const void *dev_info2)
1854 {
1855 if (((struct btrfs_device_info *)dev_info1)->max_avail >
1856 ((struct btrfs_device_info *)dev_info2)->max_avail)
1857 return -1;
1858 else if (((struct btrfs_device_info *)dev_info1)->max_avail <
1859 ((struct btrfs_device_info *)dev_info2)->max_avail)
1860 return 1;
1861 else
1862 return 0;
1863 }
1864
1865 /*
1866 * sort the devices by max_avail, in which max free extent size of each device
1867 * is stored.(Descending Sort)
1868 */
1869 static inline void btrfs_descending_sort_devices(
1870 struct btrfs_device_info *devices,
1871 size_t nr_devices)
1872 {
1873 sort(devices, nr_devices, sizeof(struct btrfs_device_info),
1874 btrfs_cmp_device_free_bytes, NULL);
1875 }
1876
1877 /*
1878 * The helper to calc the free space on the devices that can be used to store
1879 * file data.
1880 */
1881 static int btrfs_calc_avail_data_space(struct btrfs_fs_info *fs_info,
1882 u64 *free_bytes)
1883 {
1884 struct btrfs_device_info *devices_info;
1885 struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
1886 struct btrfs_device *device;
1887 u64 skip_space;
1888 u64 type;
1889 u64 avail_space;
1890 u64 min_stripe_size;
1891 int min_stripes = 1, num_stripes = 1;
1892 int i = 0, nr_devices;
1893
1894 /*
1895 * We aren't under the device list lock, so this is racy-ish, but good
1896 * enough for our purposes.
1897 */
1898 nr_devices = fs_info->fs_devices->open_devices;
1899 if (!nr_devices) {
1900 smp_mb();
1901 nr_devices = fs_info->fs_devices->open_devices;
1902 ASSERT(nr_devices);
1903 if (!nr_devices) {
1904 *free_bytes = 0;
1905 return 0;
1906 }
1907 }
1908
1909 devices_info = kmalloc_array(nr_devices, sizeof(*devices_info),
1910 GFP_KERNEL);
1911 if (!devices_info)
1912 return -ENOMEM;
1913
1914 /* calc min stripe number for data space allocation */
1915 type = btrfs_data_alloc_profile(fs_info);
1916 if (type & BTRFS_BLOCK_GROUP_RAID0) {
1917 min_stripes = 2;
1918 num_stripes = nr_devices;
1919 } else if (type & BTRFS_BLOCK_GROUP_RAID1) {
1920 min_stripes = 2;
1921 num_stripes = 2;
1922 } else if (type & BTRFS_BLOCK_GROUP_RAID10) {
1923 min_stripes = 4;
1924 num_stripes = 4;
1925 }
1926
1927 if (type & BTRFS_BLOCK_GROUP_DUP)
1928 min_stripe_size = 2 * BTRFS_STRIPE_LEN;
1929 else
1930 min_stripe_size = BTRFS_STRIPE_LEN;
1931
1932 rcu_read_lock();
1933 list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
1934 if (!device->in_fs_metadata || !device->bdev ||
1935 device->is_tgtdev_for_dev_replace)
1936 continue;
1937
1938 if (i >= nr_devices)
1939 break;
1940
1941 avail_space = device->total_bytes - device->bytes_used;
1942
1943 /* align with stripe_len */
1944 avail_space = div_u64(avail_space, BTRFS_STRIPE_LEN);
1945 avail_space *= BTRFS_STRIPE_LEN;
1946
1947 /*
1948 * In order to avoid overwriting the superblock on the drive,
1949 * btrfs starts at an offset of at least 1MB when doing chunk
1950 * allocation.
1951 */
1952 skip_space = SZ_1M;
1953
1954 /*
1955 * we can use the free space in [0, skip_space - 1], subtract
1956 * it from the total.
1957 */
1958 if (avail_space && avail_space >= skip_space)
1959 avail_space -= skip_space;
1960 else
1961 avail_space = 0;
1962
1963 if (avail_space < min_stripe_size)
1964 continue;
1965
1966 devices_info[i].dev = device;
1967 devices_info[i].max_avail = avail_space;
1968
1969 i++;
1970 }
1971 rcu_read_unlock();
1972
1973 nr_devices = i;
1974
1975 btrfs_descending_sort_devices(devices_info, nr_devices);
1976
1977 i = nr_devices - 1;
1978 avail_space = 0;
1979 while (nr_devices >= min_stripes) {
1980 if (num_stripes > nr_devices)
1981 num_stripes = nr_devices;
1982
1983 if (devices_info[i].max_avail >= min_stripe_size) {
1984 int j;
1985 u64 alloc_size;
1986
1987 avail_space += devices_info[i].max_avail * num_stripes;
1988 alloc_size = devices_info[i].max_avail;
1989 for (j = i + 1 - num_stripes; j <= i; j++)
1990 devices_info[j].max_avail -= alloc_size;
1991 }
1992 i--;
1993 nr_devices--;
1994 }
1995
1996 kfree(devices_info);
1997 *free_bytes = avail_space;
1998 return 0;
1999 }
2000
2001 /*
2002 * Calculate numbers for 'df', pessimistic in case of mixed raid profiles.
2003 *
2004 * If there's a redundant raid level at DATA block groups, use the respective
2005 * multiplier to scale the sizes.
2006 *
2007 * Unused device space usage is based on simulating the chunk allocator
2008 * algorithm that respects the device sizes and order of allocations. This is
2009 * a close approximation of the actual use but there are other factors that may
2010 * change the result (like a new metadata chunk).
2011 *
2012 * If metadata is exhausted, f_bavail will be 0.
2013 */
2014 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
2015 {
2016 struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
2017 struct btrfs_super_block *disk_super = fs_info->super_copy;
2018 struct list_head *head = &fs_info->space_info;
2019 struct btrfs_space_info *found;
2020 u64 total_used = 0;
2021 u64 total_free_data = 0;
2022 u64 total_free_meta = 0;
2023 int bits = dentry->d_sb->s_blocksize_bits;
2024 __be32 *fsid = (__be32 *)fs_info->fsid;
2025 unsigned factor = 1;
2026 struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
2027 int ret;
2028 u64 thresh = 0;
2029 int mixed = 0;
2030
2031 rcu_read_lock();
2032 list_for_each_entry_rcu(found, head, list) {
2033 if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
2034 int i;
2035
2036 total_free_data += found->disk_total - found->disk_used;
2037 total_free_data -=
2038 btrfs_account_ro_block_groups_free_space(found);
2039
2040 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
2041 if (!list_empty(&found->block_groups[i])) {
2042 switch (i) {
2043 case BTRFS_RAID_DUP:
2044 case BTRFS_RAID_RAID1:
2045 case BTRFS_RAID_RAID10:
2046 factor = 2;
2047 }
2048 }
2049 }
2050 }
2051
2052 /*
2053 * Metadata in mixed block goup profiles are accounted in data
2054 */
2055 if (!mixed && found->flags & BTRFS_BLOCK_GROUP_METADATA) {
2056 if (found->flags & BTRFS_BLOCK_GROUP_DATA)
2057 mixed = 1;
2058 else
2059 total_free_meta += found->disk_total -
2060 found->disk_used;
2061 }
2062
2063 total_used += found->disk_used;
2064 }
2065
2066 rcu_read_unlock();
2067
2068 buf->f_blocks = div_u64(btrfs_super_total_bytes(disk_super), factor);
2069 buf->f_blocks >>= bits;
2070 buf->f_bfree = buf->f_blocks - (div_u64(total_used, factor) >> bits);
2071
2072 /* Account global block reserve as used, it's in logical size already */
2073 spin_lock(&block_rsv->lock);
2074 /* Mixed block groups accounting is not byte-accurate, avoid overflow */
2075 if (buf->f_bfree >= block_rsv->size >> bits)
2076 buf->f_bfree -= block_rsv->size >> bits;
2077 else
2078 buf->f_bfree = 0;
2079 spin_unlock(&block_rsv->lock);
2080
2081 buf->f_bavail = div_u64(total_free_data, factor);
2082 ret = btrfs_calc_avail_data_space(fs_info, &total_free_data);
2083 if (ret)
2084 return ret;
2085 buf->f_bavail += div_u64(total_free_data, factor);
2086 buf->f_bavail = buf->f_bavail >> bits;
2087
2088 /*
2089 * We calculate the remaining metadata space minus global reserve. If
2090 * this is (supposedly) smaller than zero, there's no space. But this
2091 * does not hold in practice, the exhausted state happens where's still
2092 * some positive delta. So we apply some guesswork and compare the
2093 * delta to a 4M threshold. (Practically observed delta was ~2M.)
2094 *
2095 * We probably cannot calculate the exact threshold value because this
2096 * depends on the internal reservations requested by various
2097 * operations, so some operations that consume a few metadata will
2098 * succeed even if the Avail is zero. But this is better than the other
2099 * way around.
2100 */
2101 thresh = 4 * 1024 * 1024;
2102
2103 if (!mixed && total_free_meta - thresh < block_rsv->size)
2104 buf->f_bavail = 0;
2105
2106 buf->f_type = BTRFS_SUPER_MAGIC;
2107 buf->f_bsize = dentry->d_sb->s_blocksize;
2108 buf->f_namelen = BTRFS_NAME_LEN;
2109
2110 /* We treat it as constant endianness (it doesn't matter _which_)
2111 because we want the fsid to come out the same whether mounted
2112 on a big-endian or little-endian host */
2113 buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
2114 buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
2115 /* Mask in the root object ID too, to disambiguate subvols */
2116 buf->f_fsid.val[0] ^= BTRFS_I(d_inode(dentry))->root->objectid >> 32;
2117 buf->f_fsid.val[1] ^= BTRFS_I(d_inode(dentry))->root->objectid;
2118
2119 return 0;
2120 }
2121
2122 static void btrfs_kill_super(struct super_block *sb)
2123 {
2124 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2125 kill_anon_super(sb);
2126 free_fs_info(fs_info);
2127 }
2128
2129 static struct file_system_type btrfs_fs_type = {
2130 .owner = THIS_MODULE,
2131 .name = "btrfs",
2132 .mount = btrfs_mount,
2133 .kill_sb = btrfs_kill_super,
2134 .fs_flags = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,
2135 };
2136 MODULE_ALIAS_FS("btrfs");
2137
2138 static int btrfs_control_open(struct inode *inode, struct file *file)
2139 {
2140 /*
2141 * The control file's private_data is used to hold the
2142 * transaction when it is started and is used to keep
2143 * track of whether a transaction is already in progress.
2144 */
2145 file->private_data = NULL;
2146 return 0;
2147 }
2148
2149 /*
2150 * used by btrfsctl to scan devices when no FS is mounted
2151 */
2152 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
2153 unsigned long arg)
2154 {
2155 struct btrfs_ioctl_vol_args *vol;
2156 struct btrfs_fs_devices *fs_devices;
2157 int ret = -ENOTTY;
2158
2159 if (!capable(CAP_SYS_ADMIN))
2160 return -EPERM;
2161
2162 vol = memdup_user((void __user *)arg, sizeof(*vol));
2163 if (IS_ERR(vol))
2164 return PTR_ERR(vol);
2165
2166 switch (cmd) {
2167 case BTRFS_IOC_SCAN_DEV:
2168 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
2169 &btrfs_fs_type, &fs_devices);
2170 break;
2171 case BTRFS_IOC_DEVICES_READY:
2172 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
2173 &btrfs_fs_type, &fs_devices);
2174 if (ret)
2175 break;
2176 ret = !(fs_devices->num_devices == fs_devices->total_devices);
2177 break;
2178 case BTRFS_IOC_GET_SUPPORTED_FEATURES:
2179 ret = btrfs_ioctl_get_supported_features((void __user*)arg);
2180 break;
2181 }
2182
2183 kfree(vol);
2184 return ret;
2185 }
2186
2187 static int btrfs_freeze(struct super_block *sb)
2188 {
2189 struct btrfs_trans_handle *trans;
2190 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2191 struct btrfs_root *root = fs_info->tree_root;
2192
2193 set_bit(BTRFS_FS_FROZEN, &fs_info->flags);
2194 /*
2195 * We don't need a barrier here, we'll wait for any transaction that
2196 * could be in progress on other threads (and do delayed iputs that
2197 * we want to avoid on a frozen filesystem), or do the commit
2198 * ourselves.
2199 */
2200 trans = btrfs_attach_transaction_barrier(root);
2201 if (IS_ERR(trans)) {
2202 /* no transaction, don't bother */
2203 if (PTR_ERR(trans) == -ENOENT)
2204 return 0;
2205 return PTR_ERR(trans);
2206 }
2207 return btrfs_commit_transaction(trans);
2208 }
2209
2210 static int btrfs_unfreeze(struct super_block *sb)
2211 {
2212 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2213
2214 clear_bit(BTRFS_FS_FROZEN, &fs_info->flags);
2215 return 0;
2216 }
2217
2218 static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
2219 {
2220 struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
2221 struct btrfs_fs_devices *cur_devices;
2222 struct btrfs_device *dev, *first_dev = NULL;
2223 struct list_head *head;
2224 struct rcu_string *name;
2225
2226 mutex_lock(&fs_info->fs_devices->device_list_mutex);
2227 cur_devices = fs_info->fs_devices;
2228 while (cur_devices) {
2229 head = &cur_devices->devices;
2230 list_for_each_entry(dev, head, dev_list) {
2231 if (dev->missing)
2232 continue;
2233 if (!dev->name)
2234 continue;
2235 if (!first_dev || dev->devid < first_dev->devid)
2236 first_dev = dev;
2237 }
2238 cur_devices = cur_devices->seed;
2239 }
2240
2241 if (first_dev) {
2242 rcu_read_lock();
2243 name = rcu_dereference(first_dev->name);
2244 seq_escape(m, name->str, " \t\n\\");
2245 rcu_read_unlock();
2246 } else {
2247 WARN_ON(1);
2248 }
2249 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2250 return 0;
2251 }
2252
2253 static const struct super_operations btrfs_super_ops = {
2254 .drop_inode = btrfs_drop_inode,
2255 .evict_inode = btrfs_evict_inode,
2256 .put_super = btrfs_put_super,
2257 .sync_fs = btrfs_sync_fs,
2258 .show_options = btrfs_show_options,
2259 .show_devname = btrfs_show_devname,
2260 .write_inode = btrfs_write_inode,
2261 .alloc_inode = btrfs_alloc_inode,
2262 .destroy_inode = btrfs_destroy_inode,
2263 .statfs = btrfs_statfs,
2264 .remount_fs = btrfs_remount,
2265 .freeze_fs = btrfs_freeze,
2266 .unfreeze_fs = btrfs_unfreeze,
2267 };
2268
2269 static const struct file_operations btrfs_ctl_fops = {
2270 .open = btrfs_control_open,
2271 .unlocked_ioctl = btrfs_control_ioctl,
2272 .compat_ioctl = btrfs_control_ioctl,
2273 .owner = THIS_MODULE,
2274 .llseek = noop_llseek,
2275 };
2276
2277 static struct miscdevice btrfs_misc = {
2278 .minor = BTRFS_MINOR,
2279 .name = "btrfs-control",
2280 .fops = &btrfs_ctl_fops
2281 };
2282
2283 MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
2284 MODULE_ALIAS("devname:btrfs-control");
2285
2286 static int btrfs_interface_init(void)
2287 {
2288 return misc_register(&btrfs_misc);
2289 }
2290
2291 static void btrfs_interface_exit(void)
2292 {
2293 misc_deregister(&btrfs_misc);
2294 }
2295
2296 static void btrfs_print_mod_info(void)
2297 {
2298 pr_info("Btrfs loaded, crc32c=%s"
2299 #ifdef CONFIG_BTRFS_DEBUG
2300 ", debug=on"
2301 #endif
2302 #ifdef CONFIG_BTRFS_ASSERT
2303 ", assert=on"
2304 #endif
2305 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
2306 ", integrity-checker=on"
2307 #endif
2308 "\n",
2309 btrfs_crc32c_impl());
2310 }
2311
2312 static int __init init_btrfs_fs(void)
2313 {
2314 int err;
2315
2316 err = btrfs_hash_init();
2317 if (err)
2318 return err;
2319
2320 btrfs_props_init();
2321
2322 err = btrfs_init_sysfs();
2323 if (err)
2324 goto free_hash;
2325
2326 btrfs_init_compress();
2327
2328 err = btrfs_init_cachep();
2329 if (err)
2330 goto free_compress;
2331
2332 err = extent_io_init();
2333 if (err)
2334 goto free_cachep;
2335
2336 err = extent_map_init();
2337 if (err)
2338 goto free_extent_io;
2339
2340 err = ordered_data_init();
2341 if (err)
2342 goto free_extent_map;
2343
2344 err = btrfs_delayed_inode_init();
2345 if (err)
2346 goto free_ordered_data;
2347
2348 err = btrfs_auto_defrag_init();
2349 if (err)
2350 goto free_delayed_inode;
2351
2352 err = btrfs_delayed_ref_init();
2353 if (err)
2354 goto free_auto_defrag;
2355
2356 err = btrfs_prelim_ref_init();
2357 if (err)
2358 goto free_delayed_ref;
2359
2360 err = btrfs_end_io_wq_init();
2361 if (err)
2362 goto free_prelim_ref;
2363
2364 err = btrfs_interface_init();
2365 if (err)
2366 goto free_end_io_wq;
2367
2368 btrfs_init_lockdep();
2369
2370 btrfs_print_mod_info();
2371
2372 err = btrfs_run_sanity_tests();
2373 if (err)
2374 goto unregister_ioctl;
2375
2376 err = register_filesystem(&btrfs_fs_type);
2377 if (err)
2378 goto unregister_ioctl;
2379
2380 return 0;
2381
2382 unregister_ioctl:
2383 btrfs_interface_exit();
2384 free_end_io_wq:
2385 btrfs_end_io_wq_exit();
2386 free_prelim_ref:
2387 btrfs_prelim_ref_exit();
2388 free_delayed_ref:
2389 btrfs_delayed_ref_exit();
2390 free_auto_defrag:
2391 btrfs_auto_defrag_exit();
2392 free_delayed_inode:
2393 btrfs_delayed_inode_exit();
2394 free_ordered_data:
2395 ordered_data_exit();
2396 free_extent_map:
2397 extent_map_exit();
2398 free_extent_io:
2399 extent_io_exit();
2400 free_cachep:
2401 btrfs_destroy_cachep();
2402 free_compress:
2403 btrfs_exit_compress();
2404 btrfs_exit_sysfs();
2405 free_hash:
2406 btrfs_hash_exit();
2407 return err;
2408 }
2409
2410 static void __exit exit_btrfs_fs(void)
2411 {
2412 btrfs_destroy_cachep();
2413 btrfs_delayed_ref_exit();
2414 btrfs_auto_defrag_exit();
2415 btrfs_delayed_inode_exit();
2416 btrfs_prelim_ref_exit();
2417 ordered_data_exit();
2418 extent_map_exit();
2419 extent_io_exit();
2420 btrfs_interface_exit();
2421 btrfs_end_io_wq_exit();
2422 unregister_filesystem(&btrfs_fs_type);
2423 btrfs_exit_sysfs();
2424 btrfs_cleanup_fs_uuids();
2425 btrfs_exit_compress();
2426 btrfs_hash_exit();
2427 }
2428
2429 late_initcall(init_btrfs_fs);
2430 module_exit(exit_btrfs_fs)
2431
2432 MODULE_LICENSE("GPL");
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