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Btrfs: add free space tree mount option
[deliverable/linux.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 static void save_error_info(struct btrfs_fs_info *fs_info)
101 {
102 /*
103 * today we only save the error info into ram. Long term we'll
104 * also send it down to the disk
105 */
106 set_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state);
107 }
108
109 /* btrfs handle error by forcing the filesystem readonly */
110 static void btrfs_handle_error(struct btrfs_fs_info *fs_info)
111 {
112 struct super_block *sb = fs_info->sb;
113
114 if (sb->s_flags & MS_RDONLY)
115 return;
116
117 if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
118 sb->s_flags |= MS_RDONLY;
119 btrfs_info(fs_info, "forced readonly");
120 /*
121 * Note that a running device replace operation is not
122 * canceled here although there is no way to update
123 * the progress. It would add the risk of a deadlock,
124 * therefore the canceling is ommited. The only penalty
125 * is that some I/O remains active until the procedure
126 * completes. The next time when the filesystem is
127 * mounted writeable again, the device replace
128 * operation continues.
129 */
130 }
131 }
132
133 #ifdef CONFIG_PRINTK
134 /*
135 * __btrfs_std_error decodes expected errors from the caller and
136 * invokes the approciate error response.
137 */
138 __cold
139 void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function,
140 unsigned int line, int errno, const char *fmt, ...)
141 {
142 struct super_block *sb = fs_info->sb;
143 const char *errstr;
144
145 /*
146 * Special case: if the error is EROFS, and we're already
147 * under MS_RDONLY, then it is safe here.
148 */
149 if (errno == -EROFS && (sb->s_flags & MS_RDONLY))
150 return;
151
152 errstr = btrfs_decode_error(errno);
153 if (fmt) {
154 struct va_format vaf;
155 va_list args;
156
157 va_start(args, fmt);
158 vaf.fmt = fmt;
159 vaf.va = &args;
160
161 printk(KERN_CRIT
162 "BTRFS: error (device %s) in %s:%d: errno=%d %s (%pV)\n",
163 sb->s_id, function, line, errno, errstr, &vaf);
164 va_end(args);
165 } else {
166 printk(KERN_CRIT "BTRFS: error (device %s) in %s:%d: errno=%d %s\n",
167 sb->s_id, function, line, errno, errstr);
168 }
169
170 /* Don't go through full error handling during mount */
171 save_error_info(fs_info);
172 if (sb->s_flags & MS_BORN)
173 btrfs_handle_error(fs_info);
174 }
175
176 static const char * const logtypes[] = {
177 "emergency",
178 "alert",
179 "critical",
180 "error",
181 "warning",
182 "notice",
183 "info",
184 "debug",
185 };
186
187 void btrfs_printk(const struct btrfs_fs_info *fs_info, const char *fmt, ...)
188 {
189 struct super_block *sb = fs_info->sb;
190 char lvl[4];
191 struct va_format vaf;
192 va_list args;
193 const char *type = logtypes[4];
194 int kern_level;
195
196 va_start(args, fmt);
197
198 kern_level = printk_get_level(fmt);
199 if (kern_level) {
200 size_t size = printk_skip_level(fmt) - fmt;
201 memcpy(lvl, fmt, size);
202 lvl[size] = '\0';
203 fmt += size;
204 type = logtypes[kern_level - '0'];
205 } else
206 *lvl = '\0';
207
208 vaf.fmt = fmt;
209 vaf.va = &args;
210
211 printk("%sBTRFS %s (device %s): %pV\n", lvl, type, sb->s_id, &vaf);
212
213 va_end(args);
214 }
215
216 #else
217
218 void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function,
219 unsigned int line, int errno, const char *fmt, ...)
220 {
221 struct super_block *sb = fs_info->sb;
222
223 /*
224 * Special case: if the error is EROFS, and we're already
225 * under MS_RDONLY, then it is safe here.
226 */
227 if (errno == -EROFS && (sb->s_flags & MS_RDONLY))
228 return;
229
230 /* Don't go through full error handling during mount */
231 if (sb->s_flags & MS_BORN) {
232 save_error_info(fs_info);
233 btrfs_handle_error(fs_info);
234 }
235 }
236 #endif
237
238 /*
239 * We only mark the transaction aborted and then set the file system read-only.
240 * This will prevent new transactions from starting or trying to join this
241 * one.
242 *
243 * This means that error recovery at the call site is limited to freeing
244 * any local memory allocations and passing the error code up without
245 * further cleanup. The transaction should complete as it normally would
246 * in the call path but will return -EIO.
247 *
248 * We'll complete the cleanup in btrfs_end_transaction and
249 * btrfs_commit_transaction.
250 */
251 __cold
252 void __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
253 struct btrfs_root *root, const char *function,
254 unsigned int line, int errno)
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->blocks_used && list_empty(&trans->new_bgs)) {
260 const char *errstr;
261
262 errstr = btrfs_decode_error(errno);
263 btrfs_warn(root->fs_info,
264 "%s:%d: Aborting unused transaction(%s).",
265 function, line, errstr);
266 return;
267 }
268 ACCESS_ONCE(trans->transaction->aborted) = errno;
269 /* Wake up anybody who may be waiting on this transaction */
270 wake_up(&root->fs_info->transaction_wait);
271 wake_up(&root->fs_info->transaction_blocked_wait);
272 __btrfs_std_error(root->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)->tree_root);
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,
324 Opt_err,
325 };
326
327 static match_table_t tokens = {
328 {Opt_degraded, "degraded"},
329 {Opt_subvol, "subvol=%s"},
330 {Opt_subvolid, "subvolid=%s"},
331 {Opt_device, "device=%s"},
332 {Opt_nodatasum, "nodatasum"},
333 {Opt_datasum, "datasum"},
334 {Opt_nodatacow, "nodatacow"},
335 {Opt_datacow, "datacow"},
336 {Opt_nobarrier, "nobarrier"},
337 {Opt_barrier, "barrier"},
338 {Opt_max_inline, "max_inline=%s"},
339 {Opt_alloc_start, "alloc_start=%s"},
340 {Opt_thread_pool, "thread_pool=%d"},
341 {Opt_compress, "compress"},
342 {Opt_compress_type, "compress=%s"},
343 {Opt_compress_force, "compress-force"},
344 {Opt_compress_force_type, "compress-force=%s"},
345 {Opt_ssd, "ssd"},
346 {Opt_ssd_spread, "ssd_spread"},
347 {Opt_nossd, "nossd"},
348 {Opt_acl, "acl"},
349 {Opt_noacl, "noacl"},
350 {Opt_notreelog, "notreelog"},
351 {Opt_treelog, "treelog"},
352 {Opt_flushoncommit, "flushoncommit"},
353 {Opt_noflushoncommit, "noflushoncommit"},
354 {Opt_ratio, "metadata_ratio=%d"},
355 {Opt_discard, "discard"},
356 {Opt_nodiscard, "nodiscard"},
357 {Opt_space_cache, "space_cache"},
358 {Opt_space_cache_version, "space_cache=%s"},
359 {Opt_clear_cache, "clear_cache"},
360 {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
361 {Opt_enospc_debug, "enospc_debug"},
362 {Opt_noenospc_debug, "noenospc_debug"},
363 {Opt_subvolrootid, "subvolrootid=%d"},
364 {Opt_defrag, "autodefrag"},
365 {Opt_nodefrag, "noautodefrag"},
366 {Opt_inode_cache, "inode_cache"},
367 {Opt_noinode_cache, "noinode_cache"},
368 {Opt_no_space_cache, "nospace_cache"},
369 {Opt_recovery, "recovery"},
370 {Opt_skip_balance, "skip_balance"},
371 {Opt_check_integrity, "check_int"},
372 {Opt_check_integrity_including_extent_data, "check_int_data"},
373 {Opt_check_integrity_print_mask, "check_int_print_mask=%d"},
374 {Opt_rescan_uuid_tree, "rescan_uuid_tree"},
375 {Opt_fatal_errors, "fatal_errors=%s"},
376 {Opt_commit_interval, "commit=%d"},
377 {Opt_err, NULL},
378 };
379
380 /*
381 * Regular mount options parser. Everything that is needed only when
382 * reading in a new superblock is parsed here.
383 * XXX JDM: This needs to be cleaned up for remount.
384 */
385 int btrfs_parse_options(struct btrfs_root *root, char *options)
386 {
387 struct btrfs_fs_info *info = root->fs_info;
388 substring_t args[MAX_OPT_ARGS];
389 char *p, *num, *orig = NULL;
390 u64 cache_gen;
391 int intarg;
392 int ret = 0;
393 char *compress_type;
394 bool compress_force = false;
395
396 cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
397 if (btrfs_fs_compat_ro(root->fs_info, FREE_SPACE_TREE))
398 btrfs_set_opt(info->mount_opt, FREE_SPACE_TREE);
399 else if (cache_gen)
400 btrfs_set_opt(info->mount_opt, SPACE_CACHE);
401
402 if (!options)
403 goto out;
404
405 /*
406 * strsep changes the string, duplicate it because parse_options
407 * gets called twice
408 */
409 options = kstrdup(options, GFP_NOFS);
410 if (!options)
411 return -ENOMEM;
412
413 orig = options;
414
415 while ((p = strsep(&options, ",")) != NULL) {
416 int token;
417 if (!*p)
418 continue;
419
420 token = match_token(p, tokens, args);
421 switch (token) {
422 case Opt_degraded:
423 btrfs_info(root->fs_info, "allowing degraded mounts");
424 btrfs_set_opt(info->mount_opt, DEGRADED);
425 break;
426 case Opt_subvol:
427 case Opt_subvolid:
428 case Opt_subvolrootid:
429 case Opt_device:
430 /*
431 * These are parsed by btrfs_parse_early_options
432 * and can be happily ignored here.
433 */
434 break;
435 case Opt_nodatasum:
436 btrfs_set_and_info(root, NODATASUM,
437 "setting nodatasum");
438 break;
439 case Opt_datasum:
440 if (btrfs_test_opt(root, NODATASUM)) {
441 if (btrfs_test_opt(root, NODATACOW))
442 btrfs_info(root->fs_info, "setting datasum, datacow enabled");
443 else
444 btrfs_info(root->fs_info, "setting datasum");
445 }
446 btrfs_clear_opt(info->mount_opt, NODATACOW);
447 btrfs_clear_opt(info->mount_opt, NODATASUM);
448 break;
449 case Opt_nodatacow:
450 if (!btrfs_test_opt(root, NODATACOW)) {
451 if (!btrfs_test_opt(root, COMPRESS) ||
452 !btrfs_test_opt(root, FORCE_COMPRESS)) {
453 btrfs_info(root->fs_info,
454 "setting nodatacow, compression disabled");
455 } else {
456 btrfs_info(root->fs_info, "setting nodatacow");
457 }
458 }
459 btrfs_clear_opt(info->mount_opt, COMPRESS);
460 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
461 btrfs_set_opt(info->mount_opt, NODATACOW);
462 btrfs_set_opt(info->mount_opt, NODATASUM);
463 break;
464 case Opt_datacow:
465 btrfs_clear_and_info(root, NODATACOW,
466 "setting datacow");
467 break;
468 case Opt_compress_force:
469 case Opt_compress_force_type:
470 compress_force = true;
471 /* Fallthrough */
472 case Opt_compress:
473 case Opt_compress_type:
474 if (token == Opt_compress ||
475 token == Opt_compress_force ||
476 strcmp(args[0].from, "zlib") == 0) {
477 compress_type = "zlib";
478 info->compress_type = BTRFS_COMPRESS_ZLIB;
479 btrfs_set_opt(info->mount_opt, COMPRESS);
480 btrfs_clear_opt(info->mount_opt, NODATACOW);
481 btrfs_clear_opt(info->mount_opt, NODATASUM);
482 } else if (strcmp(args[0].from, "lzo") == 0) {
483 compress_type = "lzo";
484 info->compress_type = BTRFS_COMPRESS_LZO;
485 btrfs_set_opt(info->mount_opt, COMPRESS);
486 btrfs_clear_opt(info->mount_opt, NODATACOW);
487 btrfs_clear_opt(info->mount_opt, NODATASUM);
488 btrfs_set_fs_incompat(info, COMPRESS_LZO);
489 } else if (strncmp(args[0].from, "no", 2) == 0) {
490 compress_type = "no";
491 btrfs_clear_opt(info->mount_opt, COMPRESS);
492 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
493 compress_force = false;
494 } else {
495 ret = -EINVAL;
496 goto out;
497 }
498
499 if (compress_force) {
500 btrfs_set_and_info(root, FORCE_COMPRESS,
501 "force %s compression",
502 compress_type);
503 } else {
504 if (!btrfs_test_opt(root, COMPRESS))
505 btrfs_info(root->fs_info,
506 "btrfs: use %s compression",
507 compress_type);
508 /*
509 * If we remount from compress-force=xxx to
510 * compress=xxx, we need clear FORCE_COMPRESS
511 * flag, otherwise, there is no way for users
512 * to disable forcible compression separately.
513 */
514 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
515 }
516 break;
517 case Opt_ssd:
518 btrfs_set_and_info(root, SSD,
519 "use ssd allocation scheme");
520 break;
521 case Opt_ssd_spread:
522 btrfs_set_and_info(root, SSD_SPREAD,
523 "use spread ssd allocation scheme");
524 btrfs_set_opt(info->mount_opt, SSD);
525 break;
526 case Opt_nossd:
527 btrfs_set_and_info(root, NOSSD,
528 "not using ssd allocation scheme");
529 btrfs_clear_opt(info->mount_opt, SSD);
530 break;
531 case Opt_barrier:
532 btrfs_clear_and_info(root, NOBARRIER,
533 "turning on barriers");
534 break;
535 case Opt_nobarrier:
536 btrfs_set_and_info(root, NOBARRIER,
537 "turning off barriers");
538 break;
539 case Opt_thread_pool:
540 ret = match_int(&args[0], &intarg);
541 if (ret) {
542 goto out;
543 } else if (intarg > 0) {
544 info->thread_pool_size = intarg;
545 } else {
546 ret = -EINVAL;
547 goto out;
548 }
549 break;
550 case Opt_max_inline:
551 num = match_strdup(&args[0]);
552 if (num) {
553 info->max_inline = memparse(num, NULL);
554 kfree(num);
555
556 if (info->max_inline) {
557 info->max_inline = min_t(u64,
558 info->max_inline,
559 root->sectorsize);
560 }
561 btrfs_info(root->fs_info, "max_inline at %llu",
562 info->max_inline);
563 } else {
564 ret = -ENOMEM;
565 goto out;
566 }
567 break;
568 case Opt_alloc_start:
569 num = match_strdup(&args[0]);
570 if (num) {
571 mutex_lock(&info->chunk_mutex);
572 info->alloc_start = memparse(num, NULL);
573 mutex_unlock(&info->chunk_mutex);
574 kfree(num);
575 btrfs_info(root->fs_info, "allocations start at %llu",
576 info->alloc_start);
577 } else {
578 ret = -ENOMEM;
579 goto out;
580 }
581 break;
582 case Opt_acl:
583 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
584 root->fs_info->sb->s_flags |= MS_POSIXACL;
585 break;
586 #else
587 btrfs_err(root->fs_info,
588 "support for ACL not compiled in!");
589 ret = -EINVAL;
590 goto out;
591 #endif
592 case Opt_noacl:
593 root->fs_info->sb->s_flags &= ~MS_POSIXACL;
594 break;
595 case Opt_notreelog:
596 btrfs_set_and_info(root, NOTREELOG,
597 "disabling tree log");
598 break;
599 case Opt_treelog:
600 btrfs_clear_and_info(root, NOTREELOG,
601 "enabling tree log");
602 break;
603 case Opt_flushoncommit:
604 btrfs_set_and_info(root, FLUSHONCOMMIT,
605 "turning on flush-on-commit");
606 break;
607 case Opt_noflushoncommit:
608 btrfs_clear_and_info(root, FLUSHONCOMMIT,
609 "turning off flush-on-commit");
610 break;
611 case Opt_ratio:
612 ret = match_int(&args[0], &intarg);
613 if (ret) {
614 goto out;
615 } else if (intarg >= 0) {
616 info->metadata_ratio = intarg;
617 btrfs_info(root->fs_info, "metadata ratio %d",
618 info->metadata_ratio);
619 } else {
620 ret = -EINVAL;
621 goto out;
622 }
623 break;
624 case Opt_discard:
625 btrfs_set_and_info(root, DISCARD,
626 "turning on discard");
627 break;
628 case Opt_nodiscard:
629 btrfs_clear_and_info(root, DISCARD,
630 "turning off discard");
631 break;
632 case Opt_space_cache:
633 case Opt_space_cache_version:
634 if (token == Opt_space_cache ||
635 strcmp(args[0].from, "v1") == 0) {
636 btrfs_clear_opt(root->fs_info->mount_opt,
637 FREE_SPACE_TREE);
638 btrfs_set_and_info(root, SPACE_CACHE,
639 "enabling disk space caching");
640 } else if (strcmp(args[0].from, "v2") == 0) {
641 btrfs_clear_opt(root->fs_info->mount_opt,
642 SPACE_CACHE);
643 btrfs_set_and_info(root, FREE_SPACE_TREE,
644 "enabling free space tree");
645 } else {
646 ret = -EINVAL;
647 goto out;
648 }
649 break;
650 case Opt_rescan_uuid_tree:
651 btrfs_set_opt(info->mount_opt, RESCAN_UUID_TREE);
652 break;
653 case Opt_no_space_cache:
654 if (btrfs_test_opt(root, SPACE_CACHE)) {
655 btrfs_clear_and_info(root, SPACE_CACHE,
656 "disabling disk space caching");
657 }
658 if (btrfs_test_opt(root, FREE_SPACE_TREE)) {
659 btrfs_clear_and_info(root, FREE_SPACE_TREE,
660 "disabling free space tree");
661 }
662 break;
663 case Opt_inode_cache:
664 btrfs_set_pending_and_info(info, INODE_MAP_CACHE,
665 "enabling inode map caching");
666 break;
667 case Opt_noinode_cache:
668 btrfs_clear_pending_and_info(info, INODE_MAP_CACHE,
669 "disabling inode map caching");
670 break;
671 case Opt_clear_cache:
672 btrfs_set_and_info(root, CLEAR_CACHE,
673 "force clearing of disk cache");
674 break;
675 case Opt_user_subvol_rm_allowed:
676 btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
677 break;
678 case Opt_enospc_debug:
679 btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
680 break;
681 case Opt_noenospc_debug:
682 btrfs_clear_opt(info->mount_opt, ENOSPC_DEBUG);
683 break;
684 case Opt_defrag:
685 btrfs_set_and_info(root, AUTO_DEFRAG,
686 "enabling auto defrag");
687 break;
688 case Opt_nodefrag:
689 btrfs_clear_and_info(root, AUTO_DEFRAG,
690 "disabling auto defrag");
691 break;
692 case Opt_recovery:
693 btrfs_info(root->fs_info, "enabling auto recovery");
694 btrfs_set_opt(info->mount_opt, RECOVERY);
695 break;
696 case Opt_skip_balance:
697 btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
698 break;
699 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
700 case Opt_check_integrity_including_extent_data:
701 btrfs_info(root->fs_info,
702 "enabling check integrity including extent data");
703 btrfs_set_opt(info->mount_opt,
704 CHECK_INTEGRITY_INCLUDING_EXTENT_DATA);
705 btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
706 break;
707 case Opt_check_integrity:
708 btrfs_info(root->fs_info, "enabling check integrity");
709 btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
710 break;
711 case Opt_check_integrity_print_mask:
712 ret = match_int(&args[0], &intarg);
713 if (ret) {
714 goto out;
715 } else if (intarg >= 0) {
716 info->check_integrity_print_mask = intarg;
717 btrfs_info(root->fs_info, "check_integrity_print_mask 0x%x",
718 info->check_integrity_print_mask);
719 } else {
720 ret = -EINVAL;
721 goto out;
722 }
723 break;
724 #else
725 case Opt_check_integrity_including_extent_data:
726 case Opt_check_integrity:
727 case Opt_check_integrity_print_mask:
728 btrfs_err(root->fs_info,
729 "support for check_integrity* not compiled in!");
730 ret = -EINVAL;
731 goto out;
732 #endif
733 case Opt_fatal_errors:
734 if (strcmp(args[0].from, "panic") == 0)
735 btrfs_set_opt(info->mount_opt,
736 PANIC_ON_FATAL_ERROR);
737 else if (strcmp(args[0].from, "bug") == 0)
738 btrfs_clear_opt(info->mount_opt,
739 PANIC_ON_FATAL_ERROR);
740 else {
741 ret = -EINVAL;
742 goto out;
743 }
744 break;
745 case Opt_commit_interval:
746 intarg = 0;
747 ret = match_int(&args[0], &intarg);
748 if (ret < 0) {
749 btrfs_err(root->fs_info, "invalid commit interval");
750 ret = -EINVAL;
751 goto out;
752 }
753 if (intarg > 0) {
754 if (intarg > 300) {
755 btrfs_warn(root->fs_info, "excessive commit interval %d",
756 intarg);
757 }
758 info->commit_interval = intarg;
759 } else {
760 btrfs_info(root->fs_info, "using default commit interval %ds",
761 BTRFS_DEFAULT_COMMIT_INTERVAL);
762 info->commit_interval = BTRFS_DEFAULT_COMMIT_INTERVAL;
763 }
764 break;
765 case Opt_err:
766 btrfs_info(root->fs_info, "unrecognized mount option '%s'", p);
767 ret = -EINVAL;
768 goto out;
769 default:
770 break;
771 }
772 }
773 out:
774 if (btrfs_fs_compat_ro(root->fs_info, FREE_SPACE_TREE) &&
775 !btrfs_test_opt(root, FREE_SPACE_TREE) &&
776 !btrfs_test_opt(root, CLEAR_CACHE)) {
777 btrfs_err(root->fs_info, "cannot disable free space tree");
778 ret = -EINVAL;
779
780 }
781 if (!ret && btrfs_test_opt(root, SPACE_CACHE))
782 btrfs_info(root->fs_info, "disk space caching is enabled");
783 if (!ret && btrfs_test_opt(root, FREE_SPACE_TREE))
784 btrfs_info(root->fs_info, "using free space tree");
785 kfree(orig);
786 return ret;
787 }
788
789 /*
790 * Parse mount options that are required early in the mount process.
791 *
792 * All other options will be parsed on much later in the mount process and
793 * only when we need to allocate a new super block.
794 */
795 static int btrfs_parse_early_options(const char *options, fmode_t flags,
796 void *holder, char **subvol_name, u64 *subvol_objectid,
797 struct btrfs_fs_devices **fs_devices)
798 {
799 substring_t args[MAX_OPT_ARGS];
800 char *device_name, *opts, *orig, *p;
801 char *num = NULL;
802 int error = 0;
803
804 if (!options)
805 return 0;
806
807 /*
808 * strsep changes the string, duplicate it because parse_options
809 * gets called twice
810 */
811 opts = kstrdup(options, GFP_KERNEL);
812 if (!opts)
813 return -ENOMEM;
814 orig = opts;
815
816 while ((p = strsep(&opts, ",")) != NULL) {
817 int token;
818 if (!*p)
819 continue;
820
821 token = match_token(p, tokens, args);
822 switch (token) {
823 case Opt_subvol:
824 kfree(*subvol_name);
825 *subvol_name = match_strdup(&args[0]);
826 if (!*subvol_name) {
827 error = -ENOMEM;
828 goto out;
829 }
830 break;
831 case Opt_subvolid:
832 num = match_strdup(&args[0]);
833 if (num) {
834 *subvol_objectid = memparse(num, NULL);
835 kfree(num);
836 /* we want the original fs_tree */
837 if (!*subvol_objectid)
838 *subvol_objectid =
839 BTRFS_FS_TREE_OBJECTID;
840 } else {
841 error = -EINVAL;
842 goto out;
843 }
844 break;
845 case Opt_subvolrootid:
846 printk(KERN_WARNING
847 "BTRFS: 'subvolrootid' mount option is deprecated and has "
848 "no effect\n");
849 break;
850 case Opt_device:
851 device_name = match_strdup(&args[0]);
852 if (!device_name) {
853 error = -ENOMEM;
854 goto out;
855 }
856 error = btrfs_scan_one_device(device_name,
857 flags, holder, fs_devices);
858 kfree(device_name);
859 if (error)
860 goto out;
861 break;
862 default:
863 break;
864 }
865 }
866
867 out:
868 kfree(orig);
869 return error;
870 }
871
872 static char *get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
873 u64 subvol_objectid)
874 {
875 struct btrfs_root *root = fs_info->tree_root;
876 struct btrfs_root *fs_root;
877 struct btrfs_root_ref *root_ref;
878 struct btrfs_inode_ref *inode_ref;
879 struct btrfs_key key;
880 struct btrfs_path *path = NULL;
881 char *name = NULL, *ptr;
882 u64 dirid;
883 int len;
884 int ret;
885
886 path = btrfs_alloc_path();
887 if (!path) {
888 ret = -ENOMEM;
889 goto err;
890 }
891 path->leave_spinning = 1;
892
893 name = kmalloc(PATH_MAX, GFP_NOFS);
894 if (!name) {
895 ret = -ENOMEM;
896 goto err;
897 }
898 ptr = name + PATH_MAX - 1;
899 ptr[0] = '\0';
900
901 /*
902 * Walk up the subvolume trees in the tree of tree roots by root
903 * backrefs until we hit the top-level subvolume.
904 */
905 while (subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
906 key.objectid = subvol_objectid;
907 key.type = BTRFS_ROOT_BACKREF_KEY;
908 key.offset = (u64)-1;
909
910 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
911 if (ret < 0) {
912 goto err;
913 } else if (ret > 0) {
914 ret = btrfs_previous_item(root, path, subvol_objectid,
915 BTRFS_ROOT_BACKREF_KEY);
916 if (ret < 0) {
917 goto err;
918 } else if (ret > 0) {
919 ret = -ENOENT;
920 goto err;
921 }
922 }
923
924 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
925 subvol_objectid = key.offset;
926
927 root_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
928 struct btrfs_root_ref);
929 len = btrfs_root_ref_name_len(path->nodes[0], root_ref);
930 ptr -= len + 1;
931 if (ptr < name) {
932 ret = -ENAMETOOLONG;
933 goto err;
934 }
935 read_extent_buffer(path->nodes[0], ptr + 1,
936 (unsigned long)(root_ref + 1), len);
937 ptr[0] = '/';
938 dirid = btrfs_root_ref_dirid(path->nodes[0], root_ref);
939 btrfs_release_path(path);
940
941 key.objectid = subvol_objectid;
942 key.type = BTRFS_ROOT_ITEM_KEY;
943 key.offset = (u64)-1;
944 fs_root = btrfs_read_fs_root_no_name(fs_info, &key);
945 if (IS_ERR(fs_root)) {
946 ret = PTR_ERR(fs_root);
947 goto err;
948 }
949
950 /*
951 * Walk up the filesystem tree by inode refs until we hit the
952 * root directory.
953 */
954 while (dirid != BTRFS_FIRST_FREE_OBJECTID) {
955 key.objectid = dirid;
956 key.type = BTRFS_INODE_REF_KEY;
957 key.offset = (u64)-1;
958
959 ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0);
960 if (ret < 0) {
961 goto err;
962 } else if (ret > 0) {
963 ret = btrfs_previous_item(fs_root, path, dirid,
964 BTRFS_INODE_REF_KEY);
965 if (ret < 0) {
966 goto err;
967 } else if (ret > 0) {
968 ret = -ENOENT;
969 goto err;
970 }
971 }
972
973 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
974 dirid = key.offset;
975
976 inode_ref = btrfs_item_ptr(path->nodes[0],
977 path->slots[0],
978 struct btrfs_inode_ref);
979 len = btrfs_inode_ref_name_len(path->nodes[0],
980 inode_ref);
981 ptr -= len + 1;
982 if (ptr < name) {
983 ret = -ENAMETOOLONG;
984 goto err;
985 }
986 read_extent_buffer(path->nodes[0], ptr + 1,
987 (unsigned long)(inode_ref + 1), len);
988 ptr[0] = '/';
989 btrfs_release_path(path);
990 }
991 }
992
993 btrfs_free_path(path);
994 if (ptr == name + PATH_MAX - 1) {
995 name[0] = '/';
996 name[1] = '\0';
997 } else {
998 memmove(name, ptr, name + PATH_MAX - ptr);
999 }
1000 return name;
1001
1002 err:
1003 btrfs_free_path(path);
1004 kfree(name);
1005 return ERR_PTR(ret);
1006 }
1007
1008 static int get_default_subvol_objectid(struct btrfs_fs_info *fs_info, u64 *objectid)
1009 {
1010 struct btrfs_root *root = fs_info->tree_root;
1011 struct btrfs_dir_item *di;
1012 struct btrfs_path *path;
1013 struct btrfs_key location;
1014 u64 dir_id;
1015
1016 path = btrfs_alloc_path();
1017 if (!path)
1018 return -ENOMEM;
1019 path->leave_spinning = 1;
1020
1021 /*
1022 * Find the "default" dir item which points to the root item that we
1023 * will mount by default if we haven't been given a specific subvolume
1024 * to mount.
1025 */
1026 dir_id = btrfs_super_root_dir(fs_info->super_copy);
1027 di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
1028 if (IS_ERR(di)) {
1029 btrfs_free_path(path);
1030 return PTR_ERR(di);
1031 }
1032 if (!di) {
1033 /*
1034 * Ok the default dir item isn't there. This is weird since
1035 * it's always been there, but don't freak out, just try and
1036 * mount the top-level subvolume.
1037 */
1038 btrfs_free_path(path);
1039 *objectid = BTRFS_FS_TREE_OBJECTID;
1040 return 0;
1041 }
1042
1043 btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
1044 btrfs_free_path(path);
1045 *objectid = location.objectid;
1046 return 0;
1047 }
1048
1049 static int btrfs_fill_super(struct super_block *sb,
1050 struct btrfs_fs_devices *fs_devices,
1051 void *data, int silent)
1052 {
1053 struct inode *inode;
1054 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1055 struct btrfs_key key;
1056 int err;
1057
1058 sb->s_maxbytes = MAX_LFS_FILESIZE;
1059 sb->s_magic = BTRFS_SUPER_MAGIC;
1060 sb->s_op = &btrfs_super_ops;
1061 sb->s_d_op = &btrfs_dentry_operations;
1062 sb->s_export_op = &btrfs_export_ops;
1063 sb->s_xattr = btrfs_xattr_handlers;
1064 sb->s_time_gran = 1;
1065 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
1066 sb->s_flags |= MS_POSIXACL;
1067 #endif
1068 sb->s_flags |= MS_I_VERSION;
1069 sb->s_iflags |= SB_I_CGROUPWB;
1070 err = open_ctree(sb, fs_devices, (char *)data);
1071 if (err) {
1072 printk(KERN_ERR "BTRFS: open_ctree failed\n");
1073 return err;
1074 }
1075
1076 key.objectid = BTRFS_FIRST_FREE_OBJECTID;
1077 key.type = BTRFS_INODE_ITEM_KEY;
1078 key.offset = 0;
1079 inode = btrfs_iget(sb, &key, fs_info->fs_root, NULL);
1080 if (IS_ERR(inode)) {
1081 err = PTR_ERR(inode);
1082 goto fail_close;
1083 }
1084
1085 sb->s_root = d_make_root(inode);
1086 if (!sb->s_root) {
1087 err = -ENOMEM;
1088 goto fail_close;
1089 }
1090
1091 save_mount_options(sb, data);
1092 cleancache_init_fs(sb);
1093 sb->s_flags |= MS_ACTIVE;
1094 return 0;
1095
1096 fail_close:
1097 close_ctree(fs_info->tree_root);
1098 return err;
1099 }
1100
1101 int btrfs_sync_fs(struct super_block *sb, int wait)
1102 {
1103 struct btrfs_trans_handle *trans;
1104 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1105 struct btrfs_root *root = fs_info->tree_root;
1106
1107 trace_btrfs_sync_fs(wait);
1108
1109 if (!wait) {
1110 filemap_flush(fs_info->btree_inode->i_mapping);
1111 return 0;
1112 }
1113
1114 btrfs_wait_ordered_roots(fs_info, -1);
1115
1116 trans = btrfs_attach_transaction_barrier(root);
1117 if (IS_ERR(trans)) {
1118 /* no transaction, don't bother */
1119 if (PTR_ERR(trans) == -ENOENT) {
1120 /*
1121 * Exit unless we have some pending changes
1122 * that need to go through commit
1123 */
1124 if (fs_info->pending_changes == 0)
1125 return 0;
1126 /*
1127 * A non-blocking test if the fs is frozen. We must not
1128 * start a new transaction here otherwise a deadlock
1129 * happens. The pending operations are delayed to the
1130 * next commit after thawing.
1131 */
1132 if (__sb_start_write(sb, SB_FREEZE_WRITE, false))
1133 __sb_end_write(sb, SB_FREEZE_WRITE);
1134 else
1135 return 0;
1136 trans = btrfs_start_transaction(root, 0);
1137 }
1138 if (IS_ERR(trans))
1139 return PTR_ERR(trans);
1140 }
1141 return btrfs_commit_transaction(trans, root);
1142 }
1143
1144 static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
1145 {
1146 struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
1147 struct btrfs_root *root = info->tree_root;
1148 char *compress_type;
1149
1150 if (btrfs_test_opt(root, DEGRADED))
1151 seq_puts(seq, ",degraded");
1152 if (btrfs_test_opt(root, NODATASUM))
1153 seq_puts(seq, ",nodatasum");
1154 if (btrfs_test_opt(root, NODATACOW))
1155 seq_puts(seq, ",nodatacow");
1156 if (btrfs_test_opt(root, NOBARRIER))
1157 seq_puts(seq, ",nobarrier");
1158 if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE)
1159 seq_printf(seq, ",max_inline=%llu", info->max_inline);
1160 if (info->alloc_start != 0)
1161 seq_printf(seq, ",alloc_start=%llu", info->alloc_start);
1162 if (info->thread_pool_size != min_t(unsigned long,
1163 num_online_cpus() + 2, 8))
1164 seq_printf(seq, ",thread_pool=%d", info->thread_pool_size);
1165 if (btrfs_test_opt(root, COMPRESS)) {
1166 if (info->compress_type == BTRFS_COMPRESS_ZLIB)
1167 compress_type = "zlib";
1168 else
1169 compress_type = "lzo";
1170 if (btrfs_test_opt(root, FORCE_COMPRESS))
1171 seq_printf(seq, ",compress-force=%s", compress_type);
1172 else
1173 seq_printf(seq, ",compress=%s", compress_type);
1174 }
1175 if (btrfs_test_opt(root, NOSSD))
1176 seq_puts(seq, ",nossd");
1177 if (btrfs_test_opt(root, SSD_SPREAD))
1178 seq_puts(seq, ",ssd_spread");
1179 else if (btrfs_test_opt(root, SSD))
1180 seq_puts(seq, ",ssd");
1181 if (btrfs_test_opt(root, NOTREELOG))
1182 seq_puts(seq, ",notreelog");
1183 if (btrfs_test_opt(root, FLUSHONCOMMIT))
1184 seq_puts(seq, ",flushoncommit");
1185 if (btrfs_test_opt(root, DISCARD))
1186 seq_puts(seq, ",discard");
1187 if (!(root->fs_info->sb->s_flags & MS_POSIXACL))
1188 seq_puts(seq, ",noacl");
1189 if (btrfs_test_opt(root, SPACE_CACHE))
1190 seq_puts(seq, ",space_cache");
1191 else if (btrfs_test_opt(root, FREE_SPACE_TREE))
1192 seq_puts(seq, ",space_cache=v2");
1193 else
1194 seq_puts(seq, ",nospace_cache");
1195 if (btrfs_test_opt(root, RESCAN_UUID_TREE))
1196 seq_puts(seq, ",rescan_uuid_tree");
1197 if (btrfs_test_opt(root, CLEAR_CACHE))
1198 seq_puts(seq, ",clear_cache");
1199 if (btrfs_test_opt(root, USER_SUBVOL_RM_ALLOWED))
1200 seq_puts(seq, ",user_subvol_rm_allowed");
1201 if (btrfs_test_opt(root, ENOSPC_DEBUG))
1202 seq_puts(seq, ",enospc_debug");
1203 if (btrfs_test_opt(root, AUTO_DEFRAG))
1204 seq_puts(seq, ",autodefrag");
1205 if (btrfs_test_opt(root, INODE_MAP_CACHE))
1206 seq_puts(seq, ",inode_cache");
1207 if (btrfs_test_opt(root, SKIP_BALANCE))
1208 seq_puts(seq, ",skip_balance");
1209 if (btrfs_test_opt(root, RECOVERY))
1210 seq_puts(seq, ",recovery");
1211 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
1212 if (btrfs_test_opt(root, CHECK_INTEGRITY_INCLUDING_EXTENT_DATA))
1213 seq_puts(seq, ",check_int_data");
1214 else if (btrfs_test_opt(root, CHECK_INTEGRITY))
1215 seq_puts(seq, ",check_int");
1216 if (info->check_integrity_print_mask)
1217 seq_printf(seq, ",check_int_print_mask=%d",
1218 info->check_integrity_print_mask);
1219 #endif
1220 if (info->metadata_ratio)
1221 seq_printf(seq, ",metadata_ratio=%d",
1222 info->metadata_ratio);
1223 if (btrfs_test_opt(root, PANIC_ON_FATAL_ERROR))
1224 seq_puts(seq, ",fatal_errors=panic");
1225 if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL)
1226 seq_printf(seq, ",commit=%d", info->commit_interval);
1227 seq_printf(seq, ",subvolid=%llu",
1228 BTRFS_I(d_inode(dentry))->root->root_key.objectid);
1229 seq_puts(seq, ",subvol=");
1230 seq_dentry(seq, dentry, " \t\n\\");
1231 return 0;
1232 }
1233
1234 static int btrfs_test_super(struct super_block *s, void *data)
1235 {
1236 struct btrfs_fs_info *p = data;
1237 struct btrfs_fs_info *fs_info = btrfs_sb(s);
1238
1239 return fs_info->fs_devices == p->fs_devices;
1240 }
1241
1242 static int btrfs_set_super(struct super_block *s, void *data)
1243 {
1244 int err = set_anon_super(s, data);
1245 if (!err)
1246 s->s_fs_info = data;
1247 return err;
1248 }
1249
1250 /*
1251 * subvolumes are identified by ino 256
1252 */
1253 static inline int is_subvolume_inode(struct inode *inode)
1254 {
1255 if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
1256 return 1;
1257 return 0;
1258 }
1259
1260 /*
1261 * This will add subvolid=0 to the argument string while removing any subvol=
1262 * and subvolid= arguments to make sure we get the top-level root for path
1263 * walking to the subvol we want.
1264 */
1265 static char *setup_root_args(char *args)
1266 {
1267 char *buf, *dst, *sep;
1268
1269 if (!args)
1270 return kstrdup("subvolid=0", GFP_NOFS);
1271
1272 /* The worst case is that we add ",subvolid=0" to the end. */
1273 buf = dst = kmalloc(strlen(args) + strlen(",subvolid=0") + 1, GFP_NOFS);
1274 if (!buf)
1275 return NULL;
1276
1277 while (1) {
1278 sep = strchrnul(args, ',');
1279 if (!strstarts(args, "subvol=") &&
1280 !strstarts(args, "subvolid=")) {
1281 memcpy(dst, args, sep - args);
1282 dst += sep - args;
1283 *dst++ = ',';
1284 }
1285 if (*sep)
1286 args = sep + 1;
1287 else
1288 break;
1289 }
1290 strcpy(dst, "subvolid=0");
1291
1292 return buf;
1293 }
1294
1295 static struct dentry *mount_subvol(const char *subvol_name, u64 subvol_objectid,
1296 int flags, const char *device_name,
1297 char *data)
1298 {
1299 struct dentry *root;
1300 struct vfsmount *mnt = NULL;
1301 char *newargs;
1302 int ret;
1303
1304 newargs = setup_root_args(data);
1305 if (!newargs) {
1306 root = ERR_PTR(-ENOMEM);
1307 goto out;
1308 }
1309
1310 mnt = vfs_kern_mount(&btrfs_fs_type, flags, device_name, newargs);
1311 if (PTR_ERR_OR_ZERO(mnt) == -EBUSY) {
1312 if (flags & MS_RDONLY) {
1313 mnt = vfs_kern_mount(&btrfs_fs_type, flags & ~MS_RDONLY,
1314 device_name, newargs);
1315 } else {
1316 mnt = vfs_kern_mount(&btrfs_fs_type, flags | MS_RDONLY,
1317 device_name, newargs);
1318 if (IS_ERR(mnt)) {
1319 root = ERR_CAST(mnt);
1320 mnt = NULL;
1321 goto out;
1322 }
1323
1324 down_write(&mnt->mnt_sb->s_umount);
1325 ret = btrfs_remount(mnt->mnt_sb, &flags, NULL);
1326 up_write(&mnt->mnt_sb->s_umount);
1327 if (ret < 0) {
1328 root = ERR_PTR(ret);
1329 goto out;
1330 }
1331 }
1332 }
1333 if (IS_ERR(mnt)) {
1334 root = ERR_CAST(mnt);
1335 mnt = NULL;
1336 goto out;
1337 }
1338
1339 if (!subvol_name) {
1340 if (!subvol_objectid) {
1341 ret = get_default_subvol_objectid(btrfs_sb(mnt->mnt_sb),
1342 &subvol_objectid);
1343 if (ret) {
1344 root = ERR_PTR(ret);
1345 goto out;
1346 }
1347 }
1348 subvol_name = get_subvol_name_from_objectid(btrfs_sb(mnt->mnt_sb),
1349 subvol_objectid);
1350 if (IS_ERR(subvol_name)) {
1351 root = ERR_CAST(subvol_name);
1352 subvol_name = NULL;
1353 goto out;
1354 }
1355
1356 }
1357
1358 root = mount_subtree(mnt, subvol_name);
1359 /* mount_subtree() drops our reference on the vfsmount. */
1360 mnt = NULL;
1361
1362 if (!IS_ERR(root)) {
1363 struct super_block *s = root->d_sb;
1364 struct inode *root_inode = d_inode(root);
1365 u64 root_objectid = BTRFS_I(root_inode)->root->root_key.objectid;
1366
1367 ret = 0;
1368 if (!is_subvolume_inode(root_inode)) {
1369 pr_err("BTRFS: '%s' is not a valid subvolume\n",
1370 subvol_name);
1371 ret = -EINVAL;
1372 }
1373 if (subvol_objectid && root_objectid != subvol_objectid) {
1374 /*
1375 * This will also catch a race condition where a
1376 * subvolume which was passed by ID is renamed and
1377 * another subvolume is renamed over the old location.
1378 */
1379 pr_err("BTRFS: subvol '%s' does not match subvolid %llu\n",
1380 subvol_name, subvol_objectid);
1381 ret = -EINVAL;
1382 }
1383 if (ret) {
1384 dput(root);
1385 root = ERR_PTR(ret);
1386 deactivate_locked_super(s);
1387 }
1388 }
1389
1390 out:
1391 mntput(mnt);
1392 kfree(newargs);
1393 kfree(subvol_name);
1394 return root;
1395 }
1396
1397 static int parse_security_options(char *orig_opts,
1398 struct security_mnt_opts *sec_opts)
1399 {
1400 char *secdata = NULL;
1401 int ret = 0;
1402
1403 secdata = alloc_secdata();
1404 if (!secdata)
1405 return -ENOMEM;
1406 ret = security_sb_copy_data(orig_opts, secdata);
1407 if (ret) {
1408 free_secdata(secdata);
1409 return ret;
1410 }
1411 ret = security_sb_parse_opts_str(secdata, sec_opts);
1412 free_secdata(secdata);
1413 return ret;
1414 }
1415
1416 static int setup_security_options(struct btrfs_fs_info *fs_info,
1417 struct super_block *sb,
1418 struct security_mnt_opts *sec_opts)
1419 {
1420 int ret = 0;
1421
1422 /*
1423 * Call security_sb_set_mnt_opts() to check whether new sec_opts
1424 * is valid.
1425 */
1426 ret = security_sb_set_mnt_opts(sb, sec_opts, 0, NULL);
1427 if (ret)
1428 return ret;
1429
1430 #ifdef CONFIG_SECURITY
1431 if (!fs_info->security_opts.num_mnt_opts) {
1432 /* first time security setup, copy sec_opts to fs_info */
1433 memcpy(&fs_info->security_opts, sec_opts, sizeof(*sec_opts));
1434 } else {
1435 /*
1436 * Since SELinux(the only one supports security_mnt_opts) does
1437 * NOT support changing context during remount/mount same sb,
1438 * This must be the same or part of the same security options,
1439 * just free it.
1440 */
1441 security_free_mnt_opts(sec_opts);
1442 }
1443 #endif
1444 return ret;
1445 }
1446
1447 /*
1448 * Find a superblock for the given device / mount point.
1449 *
1450 * Note: This is based on get_sb_bdev from fs/super.c with a few additions
1451 * for multiple device setup. Make sure to keep it in sync.
1452 */
1453 static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
1454 const char *device_name, void *data)
1455 {
1456 struct block_device *bdev = NULL;
1457 struct super_block *s;
1458 struct btrfs_fs_devices *fs_devices = NULL;
1459 struct btrfs_fs_info *fs_info = NULL;
1460 struct security_mnt_opts new_sec_opts;
1461 fmode_t mode = FMODE_READ;
1462 char *subvol_name = NULL;
1463 u64 subvol_objectid = 0;
1464 int error = 0;
1465
1466 if (!(flags & MS_RDONLY))
1467 mode |= FMODE_WRITE;
1468
1469 error = btrfs_parse_early_options(data, mode, fs_type,
1470 &subvol_name, &subvol_objectid,
1471 &fs_devices);
1472 if (error) {
1473 kfree(subvol_name);
1474 return ERR_PTR(error);
1475 }
1476
1477 if (subvol_name || subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
1478 /* mount_subvol() will free subvol_name. */
1479 return mount_subvol(subvol_name, subvol_objectid, flags,
1480 device_name, data);
1481 }
1482
1483 security_init_mnt_opts(&new_sec_opts);
1484 if (data) {
1485 error = parse_security_options(data, &new_sec_opts);
1486 if (error)
1487 return ERR_PTR(error);
1488 }
1489
1490 error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices);
1491 if (error)
1492 goto error_sec_opts;
1493
1494 /*
1495 * Setup a dummy root and fs_info for test/set super. This is because
1496 * we don't actually fill this stuff out until open_ctree, but we need
1497 * it for searching for existing supers, so this lets us do that and
1498 * then open_ctree will properly initialize everything later.
1499 */
1500 fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_NOFS);
1501 if (!fs_info) {
1502 error = -ENOMEM;
1503 goto error_sec_opts;
1504 }
1505
1506 fs_info->fs_devices = fs_devices;
1507
1508 fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
1509 fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
1510 security_init_mnt_opts(&fs_info->security_opts);
1511 if (!fs_info->super_copy || !fs_info->super_for_commit) {
1512 error = -ENOMEM;
1513 goto error_fs_info;
1514 }
1515
1516 error = btrfs_open_devices(fs_devices, mode, fs_type);
1517 if (error)
1518 goto error_fs_info;
1519
1520 if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
1521 error = -EACCES;
1522 goto error_close_devices;
1523 }
1524
1525 bdev = fs_devices->latest_bdev;
1526 s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | MS_NOSEC,
1527 fs_info);
1528 if (IS_ERR(s)) {
1529 error = PTR_ERR(s);
1530 goto error_close_devices;
1531 }
1532
1533 if (s->s_root) {
1534 btrfs_close_devices(fs_devices);
1535 free_fs_info(fs_info);
1536 if ((flags ^ s->s_flags) & MS_RDONLY)
1537 error = -EBUSY;
1538 } else {
1539 char b[BDEVNAME_SIZE];
1540
1541 strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
1542 btrfs_sb(s)->bdev_holder = fs_type;
1543 error = btrfs_fill_super(s, fs_devices, data,
1544 flags & MS_SILENT ? 1 : 0);
1545 }
1546 if (error) {
1547 deactivate_locked_super(s);
1548 goto error_sec_opts;
1549 }
1550
1551 fs_info = btrfs_sb(s);
1552 error = setup_security_options(fs_info, s, &new_sec_opts);
1553 if (error) {
1554 deactivate_locked_super(s);
1555 goto error_sec_opts;
1556 }
1557
1558 return dget(s->s_root);
1559
1560 error_close_devices:
1561 btrfs_close_devices(fs_devices);
1562 error_fs_info:
1563 free_fs_info(fs_info);
1564 error_sec_opts:
1565 security_free_mnt_opts(&new_sec_opts);
1566 return ERR_PTR(error);
1567 }
1568
1569 static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
1570 int new_pool_size, int old_pool_size)
1571 {
1572 if (new_pool_size == old_pool_size)
1573 return;
1574
1575 fs_info->thread_pool_size = new_pool_size;
1576
1577 btrfs_info(fs_info, "resize thread pool %d -> %d",
1578 old_pool_size, new_pool_size);
1579
1580 btrfs_workqueue_set_max(fs_info->workers, new_pool_size);
1581 btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size);
1582 btrfs_workqueue_set_max(fs_info->submit_workers, new_pool_size);
1583 btrfs_workqueue_set_max(fs_info->caching_workers, new_pool_size);
1584 btrfs_workqueue_set_max(fs_info->endio_workers, new_pool_size);
1585 btrfs_workqueue_set_max(fs_info->endio_meta_workers, new_pool_size);
1586 btrfs_workqueue_set_max(fs_info->endio_meta_write_workers,
1587 new_pool_size);
1588 btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size);
1589 btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
1590 btrfs_workqueue_set_max(fs_info->delayed_workers, new_pool_size);
1591 btrfs_workqueue_set_max(fs_info->readahead_workers, new_pool_size);
1592 btrfs_workqueue_set_max(fs_info->scrub_wr_completion_workers,
1593 new_pool_size);
1594 }
1595
1596 static inline void btrfs_remount_prepare(struct btrfs_fs_info *fs_info)
1597 {
1598 set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1599 }
1600
1601 static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info,
1602 unsigned long old_opts, int flags)
1603 {
1604 if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1605 (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1606 (flags & MS_RDONLY))) {
1607 /* wait for any defraggers to finish */
1608 wait_event(fs_info->transaction_wait,
1609 (atomic_read(&fs_info->defrag_running) == 0));
1610 if (flags & MS_RDONLY)
1611 sync_filesystem(fs_info->sb);
1612 }
1613 }
1614
1615 static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
1616 unsigned long old_opts)
1617 {
1618 /*
1619 * We need cleanup all defragable inodes if the autodefragment is
1620 * close or the fs is R/O.
1621 */
1622 if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1623 (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1624 (fs_info->sb->s_flags & MS_RDONLY))) {
1625 btrfs_cleanup_defrag_inodes(fs_info);
1626 }
1627
1628 clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1629 }
1630
1631 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
1632 {
1633 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1634 struct btrfs_root *root = fs_info->tree_root;
1635 unsigned old_flags = sb->s_flags;
1636 unsigned long old_opts = fs_info->mount_opt;
1637 unsigned long old_compress_type = fs_info->compress_type;
1638 u64 old_max_inline = fs_info->max_inline;
1639 u64 old_alloc_start = fs_info->alloc_start;
1640 int old_thread_pool_size = fs_info->thread_pool_size;
1641 unsigned int old_metadata_ratio = fs_info->metadata_ratio;
1642 int ret;
1643
1644 sync_filesystem(sb);
1645 btrfs_remount_prepare(fs_info);
1646
1647 if (data) {
1648 struct security_mnt_opts new_sec_opts;
1649
1650 security_init_mnt_opts(&new_sec_opts);
1651 ret = parse_security_options(data, &new_sec_opts);
1652 if (ret)
1653 goto restore;
1654 ret = setup_security_options(fs_info, sb,
1655 &new_sec_opts);
1656 if (ret) {
1657 security_free_mnt_opts(&new_sec_opts);
1658 goto restore;
1659 }
1660 }
1661
1662 ret = btrfs_parse_options(root, data);
1663 if (ret) {
1664 ret = -EINVAL;
1665 goto restore;
1666 }
1667
1668 btrfs_remount_begin(fs_info, old_opts, *flags);
1669 btrfs_resize_thread_pool(fs_info,
1670 fs_info->thread_pool_size, old_thread_pool_size);
1671
1672 if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1673 goto out;
1674
1675 if (*flags & MS_RDONLY) {
1676 /*
1677 * this also happens on 'umount -rf' or on shutdown, when
1678 * the filesystem is busy.
1679 */
1680 cancel_work_sync(&fs_info->async_reclaim_work);
1681
1682 /* wait for the uuid_scan task to finish */
1683 down(&fs_info->uuid_tree_rescan_sem);
1684 /* avoid complains from lockdep et al. */
1685 up(&fs_info->uuid_tree_rescan_sem);
1686
1687 sb->s_flags |= MS_RDONLY;
1688
1689 /*
1690 * Setting MS_RDONLY will put the cleaner thread to
1691 * sleep at the next loop if it's already active.
1692 * If it's already asleep, we'll leave unused block
1693 * groups on disk until we're mounted read-write again
1694 * unless we clean them up here.
1695 */
1696 btrfs_delete_unused_bgs(fs_info);
1697
1698 btrfs_dev_replace_suspend_for_unmount(fs_info);
1699 btrfs_scrub_cancel(fs_info);
1700 btrfs_pause_balance(fs_info);
1701
1702 ret = btrfs_commit_super(root);
1703 if (ret)
1704 goto restore;
1705 } else {
1706 if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state)) {
1707 btrfs_err(fs_info,
1708 "Remounting read-write after error is not allowed");
1709 ret = -EINVAL;
1710 goto restore;
1711 }
1712 if (fs_info->fs_devices->rw_devices == 0) {
1713 ret = -EACCES;
1714 goto restore;
1715 }
1716
1717 if (fs_info->fs_devices->missing_devices >
1718 fs_info->num_tolerated_disk_barrier_failures &&
1719 !(*flags & MS_RDONLY)) {
1720 btrfs_warn(fs_info,
1721 "too many missing devices, writeable remount is not allowed");
1722 ret = -EACCES;
1723 goto restore;
1724 }
1725
1726 if (btrfs_super_log_root(fs_info->super_copy) != 0) {
1727 ret = -EINVAL;
1728 goto restore;
1729 }
1730
1731 ret = btrfs_cleanup_fs_roots(fs_info);
1732 if (ret)
1733 goto restore;
1734
1735 /* recover relocation */
1736 mutex_lock(&fs_info->cleaner_mutex);
1737 ret = btrfs_recover_relocation(root);
1738 mutex_unlock(&fs_info->cleaner_mutex);
1739 if (ret)
1740 goto restore;
1741
1742 ret = btrfs_resume_balance_async(fs_info);
1743 if (ret)
1744 goto restore;
1745
1746 ret = btrfs_resume_dev_replace_async(fs_info);
1747 if (ret) {
1748 btrfs_warn(fs_info, "failed to resume dev_replace");
1749 goto restore;
1750 }
1751
1752 if (!fs_info->uuid_root) {
1753 btrfs_info(fs_info, "creating UUID tree");
1754 ret = btrfs_create_uuid_tree(fs_info);
1755 if (ret) {
1756 btrfs_warn(fs_info, "failed to create the UUID tree %d", ret);
1757 goto restore;
1758 }
1759 }
1760 sb->s_flags &= ~MS_RDONLY;
1761 }
1762 out:
1763 wake_up_process(fs_info->transaction_kthread);
1764 btrfs_remount_cleanup(fs_info, old_opts);
1765 return 0;
1766
1767 restore:
1768 /* We've hit an error - don't reset MS_RDONLY */
1769 if (sb->s_flags & MS_RDONLY)
1770 old_flags |= MS_RDONLY;
1771 sb->s_flags = old_flags;
1772 fs_info->mount_opt = old_opts;
1773 fs_info->compress_type = old_compress_type;
1774 fs_info->max_inline = old_max_inline;
1775 mutex_lock(&fs_info->chunk_mutex);
1776 fs_info->alloc_start = old_alloc_start;
1777 mutex_unlock(&fs_info->chunk_mutex);
1778 btrfs_resize_thread_pool(fs_info,
1779 old_thread_pool_size, fs_info->thread_pool_size);
1780 fs_info->metadata_ratio = old_metadata_ratio;
1781 btrfs_remount_cleanup(fs_info, old_opts);
1782 return ret;
1783 }
1784
1785 /* Used to sort the devices by max_avail(descending sort) */
1786 static int btrfs_cmp_device_free_bytes(const void *dev_info1,
1787 const void *dev_info2)
1788 {
1789 if (((struct btrfs_device_info *)dev_info1)->max_avail >
1790 ((struct btrfs_device_info *)dev_info2)->max_avail)
1791 return -1;
1792 else if (((struct btrfs_device_info *)dev_info1)->max_avail <
1793 ((struct btrfs_device_info *)dev_info2)->max_avail)
1794 return 1;
1795 else
1796 return 0;
1797 }
1798
1799 /*
1800 * sort the devices by max_avail, in which max free extent size of each device
1801 * is stored.(Descending Sort)
1802 */
1803 static inline void btrfs_descending_sort_devices(
1804 struct btrfs_device_info *devices,
1805 size_t nr_devices)
1806 {
1807 sort(devices, nr_devices, sizeof(struct btrfs_device_info),
1808 btrfs_cmp_device_free_bytes, NULL);
1809 }
1810
1811 /*
1812 * The helper to calc the free space on the devices that can be used to store
1813 * file data.
1814 */
1815 static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes)
1816 {
1817 struct btrfs_fs_info *fs_info = root->fs_info;
1818 struct btrfs_device_info *devices_info;
1819 struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
1820 struct btrfs_device *device;
1821 u64 skip_space;
1822 u64 type;
1823 u64 avail_space;
1824 u64 used_space;
1825 u64 min_stripe_size;
1826 int min_stripes = 1, num_stripes = 1;
1827 int i = 0, nr_devices;
1828 int ret;
1829
1830 /*
1831 * We aren't under the device list lock, so this is racey-ish, but good
1832 * enough for our purposes.
1833 */
1834 nr_devices = fs_info->fs_devices->open_devices;
1835 if (!nr_devices) {
1836 smp_mb();
1837 nr_devices = fs_info->fs_devices->open_devices;
1838 ASSERT(nr_devices);
1839 if (!nr_devices) {
1840 *free_bytes = 0;
1841 return 0;
1842 }
1843 }
1844
1845 devices_info = kmalloc_array(nr_devices, sizeof(*devices_info),
1846 GFP_NOFS);
1847 if (!devices_info)
1848 return -ENOMEM;
1849
1850 /* calc min stripe number for data space alloction */
1851 type = btrfs_get_alloc_profile(root, 1);
1852 if (type & BTRFS_BLOCK_GROUP_RAID0) {
1853 min_stripes = 2;
1854 num_stripes = nr_devices;
1855 } else if (type & BTRFS_BLOCK_GROUP_RAID1) {
1856 min_stripes = 2;
1857 num_stripes = 2;
1858 } else if (type & BTRFS_BLOCK_GROUP_RAID10) {
1859 min_stripes = 4;
1860 num_stripes = 4;
1861 }
1862
1863 if (type & BTRFS_BLOCK_GROUP_DUP)
1864 min_stripe_size = 2 * BTRFS_STRIPE_LEN;
1865 else
1866 min_stripe_size = BTRFS_STRIPE_LEN;
1867
1868 if (fs_info->alloc_start)
1869 mutex_lock(&fs_devices->device_list_mutex);
1870 rcu_read_lock();
1871 list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
1872 if (!device->in_fs_metadata || !device->bdev ||
1873 device->is_tgtdev_for_dev_replace)
1874 continue;
1875
1876 if (i >= nr_devices)
1877 break;
1878
1879 avail_space = device->total_bytes - device->bytes_used;
1880
1881 /* align with stripe_len */
1882 avail_space = div_u64(avail_space, BTRFS_STRIPE_LEN);
1883 avail_space *= BTRFS_STRIPE_LEN;
1884
1885 /*
1886 * In order to avoid overwritting the superblock on the drive,
1887 * btrfs starts at an offset of at least 1MB when doing chunk
1888 * allocation.
1889 */
1890 skip_space = 1024 * 1024;
1891
1892 /* user can set the offset in fs_info->alloc_start. */
1893 if (fs_info->alloc_start &&
1894 fs_info->alloc_start + BTRFS_STRIPE_LEN <=
1895 device->total_bytes) {
1896 rcu_read_unlock();
1897 skip_space = max(fs_info->alloc_start, skip_space);
1898
1899 /*
1900 * btrfs can not use the free space in
1901 * [0, skip_space - 1], we must subtract it from the
1902 * total. In order to implement it, we account the used
1903 * space in this range first.
1904 */
1905 ret = btrfs_account_dev_extents_size(device, 0,
1906 skip_space - 1,
1907 &used_space);
1908 if (ret) {
1909 kfree(devices_info);
1910 mutex_unlock(&fs_devices->device_list_mutex);
1911 return ret;
1912 }
1913
1914 rcu_read_lock();
1915
1916 /* calc the free space in [0, skip_space - 1] */
1917 skip_space -= used_space;
1918 }
1919
1920 /*
1921 * we can use the free space in [0, skip_space - 1], subtract
1922 * it from the total.
1923 */
1924 if (avail_space && avail_space >= skip_space)
1925 avail_space -= skip_space;
1926 else
1927 avail_space = 0;
1928
1929 if (avail_space < min_stripe_size)
1930 continue;
1931
1932 devices_info[i].dev = device;
1933 devices_info[i].max_avail = avail_space;
1934
1935 i++;
1936 }
1937 rcu_read_unlock();
1938 if (fs_info->alloc_start)
1939 mutex_unlock(&fs_devices->device_list_mutex);
1940
1941 nr_devices = i;
1942
1943 btrfs_descending_sort_devices(devices_info, nr_devices);
1944
1945 i = nr_devices - 1;
1946 avail_space = 0;
1947 while (nr_devices >= min_stripes) {
1948 if (num_stripes > nr_devices)
1949 num_stripes = nr_devices;
1950
1951 if (devices_info[i].max_avail >= min_stripe_size) {
1952 int j;
1953 u64 alloc_size;
1954
1955 avail_space += devices_info[i].max_avail * num_stripes;
1956 alloc_size = devices_info[i].max_avail;
1957 for (j = i + 1 - num_stripes; j <= i; j++)
1958 devices_info[j].max_avail -= alloc_size;
1959 }
1960 i--;
1961 nr_devices--;
1962 }
1963
1964 kfree(devices_info);
1965 *free_bytes = avail_space;
1966 return 0;
1967 }
1968
1969 /*
1970 * Calculate numbers for 'df', pessimistic in case of mixed raid profiles.
1971 *
1972 * If there's a redundant raid level at DATA block groups, use the respective
1973 * multiplier to scale the sizes.
1974 *
1975 * Unused device space usage is based on simulating the chunk allocator
1976 * algorithm that respects the device sizes, order of allocations and the
1977 * 'alloc_start' value, this is a close approximation of the actual use but
1978 * there are other factors that may change the result (like a new metadata
1979 * chunk).
1980 *
1981 * FIXME: not accurate for mixed block groups, total and free/used are ok,
1982 * available appears slightly larger.
1983 */
1984 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
1985 {
1986 struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
1987 struct btrfs_super_block *disk_super = fs_info->super_copy;
1988 struct list_head *head = &fs_info->space_info;
1989 struct btrfs_space_info *found;
1990 u64 total_used = 0;
1991 u64 total_free_data = 0;
1992 int bits = dentry->d_sb->s_blocksize_bits;
1993 __be32 *fsid = (__be32 *)fs_info->fsid;
1994 unsigned factor = 1;
1995 struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
1996 int ret;
1997
1998 /*
1999 * holding chunk_muext to avoid allocating new chunks, holding
2000 * device_list_mutex to avoid the device being removed
2001 */
2002 rcu_read_lock();
2003 list_for_each_entry_rcu(found, head, list) {
2004 if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
2005 int i;
2006
2007 total_free_data += found->disk_total - found->disk_used;
2008 total_free_data -=
2009 btrfs_account_ro_block_groups_free_space(found);
2010
2011 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
2012 if (!list_empty(&found->block_groups[i])) {
2013 switch (i) {
2014 case BTRFS_RAID_DUP:
2015 case BTRFS_RAID_RAID1:
2016 case BTRFS_RAID_RAID10:
2017 factor = 2;
2018 }
2019 }
2020 }
2021 }
2022
2023 total_used += found->disk_used;
2024 }
2025
2026 rcu_read_unlock();
2027
2028 buf->f_blocks = div_u64(btrfs_super_total_bytes(disk_super), factor);
2029 buf->f_blocks >>= bits;
2030 buf->f_bfree = buf->f_blocks - (div_u64(total_used, factor) >> bits);
2031
2032 /* Account global block reserve as used, it's in logical size already */
2033 spin_lock(&block_rsv->lock);
2034 buf->f_bfree -= block_rsv->size >> bits;
2035 spin_unlock(&block_rsv->lock);
2036
2037 buf->f_bavail = div_u64(total_free_data, factor);
2038 ret = btrfs_calc_avail_data_space(fs_info->tree_root, &total_free_data);
2039 if (ret)
2040 return ret;
2041 buf->f_bavail += div_u64(total_free_data, factor);
2042 buf->f_bavail = buf->f_bavail >> bits;
2043
2044 buf->f_type = BTRFS_SUPER_MAGIC;
2045 buf->f_bsize = dentry->d_sb->s_blocksize;
2046 buf->f_namelen = BTRFS_NAME_LEN;
2047
2048 /* We treat it as constant endianness (it doesn't matter _which_)
2049 because we want the fsid to come out the same whether mounted
2050 on a big-endian or little-endian host */
2051 buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
2052 buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
2053 /* Mask in the root object ID too, to disambiguate subvols */
2054 buf->f_fsid.val[0] ^= BTRFS_I(d_inode(dentry))->root->objectid >> 32;
2055 buf->f_fsid.val[1] ^= BTRFS_I(d_inode(dentry))->root->objectid;
2056
2057 return 0;
2058 }
2059
2060 static void btrfs_kill_super(struct super_block *sb)
2061 {
2062 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2063 kill_anon_super(sb);
2064 free_fs_info(fs_info);
2065 }
2066
2067 static struct file_system_type btrfs_fs_type = {
2068 .owner = THIS_MODULE,
2069 .name = "btrfs",
2070 .mount = btrfs_mount,
2071 .kill_sb = btrfs_kill_super,
2072 .fs_flags = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,
2073 };
2074 MODULE_ALIAS_FS("btrfs");
2075
2076 static int btrfs_control_open(struct inode *inode, struct file *file)
2077 {
2078 /*
2079 * The control file's private_data is used to hold the
2080 * transaction when it is started and is used to keep
2081 * track of whether a transaction is already in progress.
2082 */
2083 file->private_data = NULL;
2084 return 0;
2085 }
2086
2087 /*
2088 * used by btrfsctl to scan devices when no FS is mounted
2089 */
2090 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
2091 unsigned long arg)
2092 {
2093 struct btrfs_ioctl_vol_args *vol;
2094 struct btrfs_fs_devices *fs_devices;
2095 int ret = -ENOTTY;
2096
2097 if (!capable(CAP_SYS_ADMIN))
2098 return -EPERM;
2099
2100 vol = memdup_user((void __user *)arg, sizeof(*vol));
2101 if (IS_ERR(vol))
2102 return PTR_ERR(vol);
2103
2104 switch (cmd) {
2105 case BTRFS_IOC_SCAN_DEV:
2106 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
2107 &btrfs_fs_type, &fs_devices);
2108 break;
2109 case BTRFS_IOC_DEVICES_READY:
2110 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
2111 &btrfs_fs_type, &fs_devices);
2112 if (ret)
2113 break;
2114 ret = !(fs_devices->num_devices == fs_devices->total_devices);
2115 break;
2116 }
2117
2118 kfree(vol);
2119 return ret;
2120 }
2121
2122 static int btrfs_freeze(struct super_block *sb)
2123 {
2124 struct btrfs_trans_handle *trans;
2125 struct btrfs_root *root = btrfs_sb(sb)->tree_root;
2126
2127 trans = btrfs_attach_transaction_barrier(root);
2128 if (IS_ERR(trans)) {
2129 /* no transaction, don't bother */
2130 if (PTR_ERR(trans) == -ENOENT)
2131 return 0;
2132 return PTR_ERR(trans);
2133 }
2134 return btrfs_commit_transaction(trans, root);
2135 }
2136
2137 static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
2138 {
2139 struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
2140 struct btrfs_fs_devices *cur_devices;
2141 struct btrfs_device *dev, *first_dev = NULL;
2142 struct list_head *head;
2143 struct rcu_string *name;
2144
2145 mutex_lock(&fs_info->fs_devices->device_list_mutex);
2146 cur_devices = fs_info->fs_devices;
2147 while (cur_devices) {
2148 head = &cur_devices->devices;
2149 list_for_each_entry(dev, head, dev_list) {
2150 if (dev->missing)
2151 continue;
2152 if (!dev->name)
2153 continue;
2154 if (!first_dev || dev->devid < first_dev->devid)
2155 first_dev = dev;
2156 }
2157 cur_devices = cur_devices->seed;
2158 }
2159
2160 if (first_dev) {
2161 rcu_read_lock();
2162 name = rcu_dereference(first_dev->name);
2163 seq_escape(m, name->str, " \t\n\\");
2164 rcu_read_unlock();
2165 } else {
2166 WARN_ON(1);
2167 }
2168 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2169 return 0;
2170 }
2171
2172 static const struct super_operations btrfs_super_ops = {
2173 .drop_inode = btrfs_drop_inode,
2174 .evict_inode = btrfs_evict_inode,
2175 .put_super = btrfs_put_super,
2176 .sync_fs = btrfs_sync_fs,
2177 .show_options = btrfs_show_options,
2178 .show_devname = btrfs_show_devname,
2179 .write_inode = btrfs_write_inode,
2180 .alloc_inode = btrfs_alloc_inode,
2181 .destroy_inode = btrfs_destroy_inode,
2182 .statfs = btrfs_statfs,
2183 .remount_fs = btrfs_remount,
2184 .freeze_fs = btrfs_freeze,
2185 };
2186
2187 static const struct file_operations btrfs_ctl_fops = {
2188 .open = btrfs_control_open,
2189 .unlocked_ioctl = btrfs_control_ioctl,
2190 .compat_ioctl = btrfs_control_ioctl,
2191 .owner = THIS_MODULE,
2192 .llseek = noop_llseek,
2193 };
2194
2195 static struct miscdevice btrfs_misc = {
2196 .minor = BTRFS_MINOR,
2197 .name = "btrfs-control",
2198 .fops = &btrfs_ctl_fops
2199 };
2200
2201 MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
2202 MODULE_ALIAS("devname:btrfs-control");
2203
2204 static int btrfs_interface_init(void)
2205 {
2206 return misc_register(&btrfs_misc);
2207 }
2208
2209 static void btrfs_interface_exit(void)
2210 {
2211 misc_deregister(&btrfs_misc);
2212 }
2213
2214 static void btrfs_print_info(void)
2215 {
2216 printk(KERN_INFO "Btrfs loaded"
2217 #ifdef CONFIG_BTRFS_DEBUG
2218 ", debug=on"
2219 #endif
2220 #ifdef CONFIG_BTRFS_ASSERT
2221 ", assert=on"
2222 #endif
2223 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
2224 ", integrity-checker=on"
2225 #endif
2226 "\n");
2227 }
2228
2229 static int btrfs_run_sanity_tests(void)
2230 {
2231 int ret;
2232
2233 ret = btrfs_init_test_fs();
2234 if (ret)
2235 return ret;
2236
2237 ret = btrfs_test_free_space_cache();
2238 if (ret)
2239 goto out;
2240 ret = btrfs_test_extent_buffer_operations();
2241 if (ret)
2242 goto out;
2243 ret = btrfs_test_extent_io();
2244 if (ret)
2245 goto out;
2246 ret = btrfs_test_inodes();
2247 if (ret)
2248 goto out;
2249 ret = btrfs_test_qgroups();
2250 if (ret)
2251 goto out;
2252 ret = btrfs_test_free_space_tree();
2253 out:
2254 btrfs_destroy_test_fs();
2255 return ret;
2256 }
2257
2258 static int __init init_btrfs_fs(void)
2259 {
2260 int err;
2261
2262 err = btrfs_hash_init();
2263 if (err)
2264 return err;
2265
2266 btrfs_props_init();
2267
2268 err = btrfs_init_sysfs();
2269 if (err)
2270 goto free_hash;
2271
2272 btrfs_init_compress();
2273
2274 err = btrfs_init_cachep();
2275 if (err)
2276 goto free_compress;
2277
2278 err = extent_io_init();
2279 if (err)
2280 goto free_cachep;
2281
2282 err = extent_map_init();
2283 if (err)
2284 goto free_extent_io;
2285
2286 err = ordered_data_init();
2287 if (err)
2288 goto free_extent_map;
2289
2290 err = btrfs_delayed_inode_init();
2291 if (err)
2292 goto free_ordered_data;
2293
2294 err = btrfs_auto_defrag_init();
2295 if (err)
2296 goto free_delayed_inode;
2297
2298 err = btrfs_delayed_ref_init();
2299 if (err)
2300 goto free_auto_defrag;
2301
2302 err = btrfs_prelim_ref_init();
2303 if (err)
2304 goto free_delayed_ref;
2305
2306 err = btrfs_end_io_wq_init();
2307 if (err)
2308 goto free_prelim_ref;
2309
2310 err = btrfs_interface_init();
2311 if (err)
2312 goto free_end_io_wq;
2313
2314 btrfs_init_lockdep();
2315
2316 btrfs_print_info();
2317
2318 err = btrfs_run_sanity_tests();
2319 if (err)
2320 goto unregister_ioctl;
2321
2322 err = register_filesystem(&btrfs_fs_type);
2323 if (err)
2324 goto unregister_ioctl;
2325
2326 return 0;
2327
2328 unregister_ioctl:
2329 btrfs_interface_exit();
2330 free_end_io_wq:
2331 btrfs_end_io_wq_exit();
2332 free_prelim_ref:
2333 btrfs_prelim_ref_exit();
2334 free_delayed_ref:
2335 btrfs_delayed_ref_exit();
2336 free_auto_defrag:
2337 btrfs_auto_defrag_exit();
2338 free_delayed_inode:
2339 btrfs_delayed_inode_exit();
2340 free_ordered_data:
2341 ordered_data_exit();
2342 free_extent_map:
2343 extent_map_exit();
2344 free_extent_io:
2345 extent_io_exit();
2346 free_cachep:
2347 btrfs_destroy_cachep();
2348 free_compress:
2349 btrfs_exit_compress();
2350 btrfs_exit_sysfs();
2351 free_hash:
2352 btrfs_hash_exit();
2353 return err;
2354 }
2355
2356 static void __exit exit_btrfs_fs(void)
2357 {
2358 btrfs_destroy_cachep();
2359 btrfs_delayed_ref_exit();
2360 btrfs_auto_defrag_exit();
2361 btrfs_delayed_inode_exit();
2362 btrfs_prelim_ref_exit();
2363 ordered_data_exit();
2364 extent_map_exit();
2365 extent_io_exit();
2366 btrfs_interface_exit();
2367 btrfs_end_io_wq_exit();
2368 unregister_filesystem(&btrfs_fs_type);
2369 btrfs_exit_sysfs();
2370 btrfs_cleanup_fs_uuids();
2371 btrfs_exit_compress();
2372 btrfs_hash_exit();
2373 }
2374
2375 late_initcall(init_btrfs_fs);
2376 module_exit(exit_btrfs_fs)
2377
2378 MODULE_LICENSE("GPL");
Linux kernel - Deliverables
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