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
btrfs_decode_error(int errno)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
save_error_info(struct btrfs_fs_info * fs_info)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 */
btrfs_handle_error(struct btrfs_fs_info * fs_info)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 /*
134 * __btrfs_std_error decodes expected errors from the caller and
135 * invokes the approciate error response.
136 */
137 __cold
__btrfs_std_error(struct btrfs_fs_info * fs_info,const char * function,unsigned int line,int errno,const char * fmt,...)138 void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function,
139 unsigned int line, int errno, const char *fmt, ...)
140 {
141 struct super_block *sb = fs_info->sb;
142 #ifdef CONFIG_PRINTK
143 const char *errstr;
144 #endif
145
146 /*
147 * Special case: if the error is EROFS, and we're already
148 * under MS_RDONLY, then it is safe here.
149 */
150 if (errno == -EROFS && (sb->s_flags & MS_RDONLY))
151 return;
152
153 #ifdef CONFIG_PRINTK
154 errstr = btrfs_decode_error(errno);
155 if (fmt) {
156 struct va_format vaf;
157 va_list args;
158
159 va_start(args, fmt);
160 vaf.fmt = fmt;
161 vaf.va = &args;
162
163 printk(KERN_CRIT
164 "BTRFS: error (device %s) in %s:%d: errno=%d %s (%pV)\n",
165 sb->s_id, function, line, errno, errstr, &vaf);
166 va_end(args);
167 } else {
168 printk(KERN_CRIT "BTRFS: error (device %s) in %s:%d: errno=%d %s\n",
169 sb->s_id, function, line, errno, errstr);
170 }
171 #endif
172
173 /* Don't go through full error handling during mount */
174 save_error_info(fs_info);
175 if (sb->s_flags & MS_BORN)
176 btrfs_handle_error(fs_info);
177 }
178
179 #ifdef CONFIG_PRINTK
180 static const char * const logtypes[] = {
181 "emergency",
182 "alert",
183 "critical",
184 "error",
185 "warning",
186 "notice",
187 "info",
188 "debug",
189 };
190
btrfs_printk(const struct btrfs_fs_info * fs_info,const char * fmt,...)191 void btrfs_printk(const struct btrfs_fs_info *fs_info, const char *fmt, ...)
192 {
193 struct super_block *sb = fs_info->sb;
194 char lvl[4];
195 struct va_format vaf;
196 va_list args;
197 const char *type = logtypes[4];
198 int kern_level;
199
200 va_start(args, fmt);
201
202 kern_level = printk_get_level(fmt);
203 if (kern_level) {
204 size_t size = printk_skip_level(fmt) - fmt;
205 memcpy(lvl, fmt, size);
206 lvl[size] = '\0';
207 fmt += size;
208 type = logtypes[kern_level - '0'];
209 } else
210 *lvl = '\0';
211
212 vaf.fmt = fmt;
213 vaf.va = &args;
214
215 printk("%sBTRFS %s (device %s): %pV\n", lvl, type, sb->s_id, &vaf);
216
217 va_end(args);
218 }
219 #endif
220
221 /*
222 * We only mark the transaction aborted and then set the file system read-only.
223 * This will prevent new transactions from starting or trying to join this
224 * one.
225 *
226 * This means that error recovery at the call site is limited to freeing
227 * any local memory allocations and passing the error code up without
228 * further cleanup. The transaction should complete as it normally would
229 * in the call path but will return -EIO.
230 *
231 * We'll complete the cleanup in btrfs_end_transaction and
232 * btrfs_commit_transaction.
233 */
234 __cold
__btrfs_abort_transaction(struct btrfs_trans_handle * trans,struct btrfs_root * root,const char * function,unsigned int line,int errno)235 void __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
236 struct btrfs_root *root, const char *function,
237 unsigned int line, int errno)
238 {
239 trans->aborted = errno;
240 /* Nothing used. The other threads that have joined this
241 * transaction may be able to continue. */
242 if (!trans->dirty && list_empty(&trans->new_bgs)) {
243 const char *errstr;
244
245 errstr = btrfs_decode_error(errno);
246 btrfs_warn(root->fs_info,
247 "%s:%d: Aborting unused transaction(%s).",
248 function, line, errstr);
249 return;
250 }
251 ACCESS_ONCE(trans->transaction->aborted) = errno;
252 /* Wake up anybody who may be waiting on this transaction */
253 wake_up(&root->fs_info->transaction_wait);
254 wake_up(&root->fs_info->transaction_blocked_wait);
255 __btrfs_std_error(root->fs_info, function, line, errno, NULL);
256 }
257 /*
258 * __btrfs_panic decodes unexpected, fatal errors from the caller,
259 * issues an alert, and either panics or BUGs, depending on mount options.
260 */
261 __cold
__btrfs_panic(struct btrfs_fs_info * fs_info,const char * function,unsigned int line,int errno,const char * fmt,...)262 void __btrfs_panic(struct btrfs_fs_info *fs_info, const char *function,
263 unsigned int line, int errno, const char *fmt, ...)
264 {
265 char *s_id = "<unknown>";
266 const char *errstr;
267 struct va_format vaf = { .fmt = fmt };
268 va_list args;
269
270 if (fs_info)
271 s_id = fs_info->sb->s_id;
272
273 va_start(args, fmt);
274 vaf.va = &args;
275
276 errstr = btrfs_decode_error(errno);
277 if (fs_info && (fs_info->mount_opt & BTRFS_MOUNT_PANIC_ON_FATAL_ERROR))
278 panic(KERN_CRIT "BTRFS panic (device %s) in %s:%d: %pV (errno=%d %s)\n",
279 s_id, function, line, &vaf, errno, errstr);
280
281 btrfs_crit(fs_info, "panic in %s:%d: %pV (errno=%d %s)",
282 function, line, &vaf, errno, errstr);
283 va_end(args);
284 /* Caller calls BUG() */
285 }
286
btrfs_put_super(struct super_block * sb)287 static void btrfs_put_super(struct super_block *sb)
288 {
289 close_ctree(btrfs_sb(sb)->tree_root);
290 }
291
292 enum {
293 Opt_degraded, Opt_subvol, Opt_subvolid, Opt_device, Opt_nodatasum,
294 Opt_nodatacow, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd,
295 Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl, Opt_compress,
296 Opt_compress_type, Opt_compress_force, Opt_compress_force_type,
297 Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard,
298 Opt_space_cache, Opt_clear_cache, Opt_user_subvol_rm_allowed,
299 Opt_enospc_debug, Opt_subvolrootid, Opt_defrag, Opt_inode_cache,
300 Opt_no_space_cache, Opt_recovery, Opt_skip_balance,
301 Opt_check_integrity, Opt_check_integrity_including_extent_data,
302 Opt_check_integrity_print_mask, Opt_fatal_errors, Opt_rescan_uuid_tree,
303 Opt_commit_interval, Opt_barrier, Opt_nodefrag, Opt_nodiscard,
304 Opt_noenospc_debug, Opt_noflushoncommit, Opt_acl, Opt_datacow,
305 Opt_datasum, Opt_treelog, Opt_noinode_cache,
306 #ifdef CONFIG_BTRFS_DEBUG
307 Opt_fragment_data, Opt_fragment_metadata, Opt_fragment_all,
308 #endif
309 Opt_err,
310 };
311
312 static match_table_t tokens = {
313 {Opt_degraded, "degraded"},
314 {Opt_subvol, "subvol=%s"},
315 {Opt_subvolid, "subvolid=%s"},
316 {Opt_device, "device=%s"},
317 {Opt_nodatasum, "nodatasum"},
318 {Opt_datasum, "datasum"},
319 {Opt_nodatacow, "nodatacow"},
320 {Opt_datacow, "datacow"},
321 {Opt_nobarrier, "nobarrier"},
322 {Opt_barrier, "barrier"},
323 {Opt_max_inline, "max_inline=%s"},
324 {Opt_alloc_start, "alloc_start=%s"},
325 {Opt_thread_pool, "thread_pool=%d"},
326 {Opt_compress, "compress"},
327 {Opt_compress_type, "compress=%s"},
328 {Opt_compress_force, "compress-force"},
329 {Opt_compress_force_type, "compress-force=%s"},
330 {Opt_ssd, "ssd"},
331 {Opt_ssd_spread, "ssd_spread"},
332 {Opt_nossd, "nossd"},
333 {Opt_acl, "acl"},
334 {Opt_noacl, "noacl"},
335 {Opt_notreelog, "notreelog"},
336 {Opt_treelog, "treelog"},
337 {Opt_flushoncommit, "flushoncommit"},
338 {Opt_noflushoncommit, "noflushoncommit"},
339 {Opt_ratio, "metadata_ratio=%d"},
340 {Opt_discard, "discard"},
341 {Opt_nodiscard, "nodiscard"},
342 {Opt_space_cache, "space_cache"},
343 {Opt_clear_cache, "clear_cache"},
344 {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
345 {Opt_enospc_debug, "enospc_debug"},
346 {Opt_noenospc_debug, "noenospc_debug"},
347 {Opt_subvolrootid, "subvolrootid=%d"},
348 {Opt_defrag, "autodefrag"},
349 {Opt_nodefrag, "noautodefrag"},
350 {Opt_inode_cache, "inode_cache"},
351 {Opt_noinode_cache, "noinode_cache"},
352 {Opt_no_space_cache, "nospace_cache"},
353 {Opt_recovery, "recovery"},
354 {Opt_skip_balance, "skip_balance"},
355 {Opt_check_integrity, "check_int"},
356 {Opt_check_integrity_including_extent_data, "check_int_data"},
357 {Opt_check_integrity_print_mask, "check_int_print_mask=%d"},
358 {Opt_rescan_uuid_tree, "rescan_uuid_tree"},
359 {Opt_fatal_errors, "fatal_errors=%s"},
360 {Opt_commit_interval, "commit=%d"},
361 #ifdef CONFIG_BTRFS_DEBUG
362 {Opt_fragment_data, "fragment=data"},
363 {Opt_fragment_metadata, "fragment=metadata"},
364 {Opt_fragment_all, "fragment=all"},
365 #endif
366 {Opt_err, NULL},
367 };
368
369 /*
370 * Regular mount options parser. Everything that is needed only when
371 * reading in a new superblock is parsed here.
372 * XXX JDM: This needs to be cleaned up for remount.
373 */
btrfs_parse_options(struct btrfs_root * root,char * options)374 int btrfs_parse_options(struct btrfs_root *root, char *options)
375 {
376 struct btrfs_fs_info *info = root->fs_info;
377 substring_t args[MAX_OPT_ARGS];
378 char *p, *num, *orig = NULL;
379 u64 cache_gen;
380 int intarg;
381 int ret = 0;
382 char *compress_type;
383 bool compress_force = false;
384
385 cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
386 if (cache_gen)
387 btrfs_set_opt(info->mount_opt, SPACE_CACHE);
388
389 if (!options)
390 goto out;
391
392 /*
393 * strsep changes the string, duplicate it because parse_options
394 * gets called twice
395 */
396 options = kstrdup(options, GFP_NOFS);
397 if (!options)
398 return -ENOMEM;
399
400 orig = options;
401
402 while ((p = strsep(&options, ",")) != NULL) {
403 int token;
404 if (!*p)
405 continue;
406
407 token = match_token(p, tokens, args);
408 switch (token) {
409 case Opt_degraded:
410 btrfs_info(root->fs_info, "allowing degraded mounts");
411 btrfs_set_opt(info->mount_opt, DEGRADED);
412 break;
413 case Opt_subvol:
414 case Opt_subvolid:
415 case Opt_subvolrootid:
416 case Opt_device:
417 /*
418 * These are parsed by btrfs_parse_early_options
419 * and can be happily ignored here.
420 */
421 break;
422 case Opt_nodatasum:
423 btrfs_set_and_info(root, NODATASUM,
424 "setting nodatasum");
425 break;
426 case Opt_datasum:
427 if (btrfs_test_opt(root, NODATASUM)) {
428 if (btrfs_test_opt(root, NODATACOW))
429 btrfs_info(root->fs_info, "setting datasum, datacow enabled");
430 else
431 btrfs_info(root->fs_info, "setting datasum");
432 }
433 btrfs_clear_opt(info->mount_opt, NODATACOW);
434 btrfs_clear_opt(info->mount_opt, NODATASUM);
435 break;
436 case Opt_nodatacow:
437 if (!btrfs_test_opt(root, NODATACOW)) {
438 if (!btrfs_test_opt(root, COMPRESS) ||
439 !btrfs_test_opt(root, FORCE_COMPRESS)) {
440 btrfs_info(root->fs_info,
441 "setting nodatacow, compression disabled");
442 } else {
443 btrfs_info(root->fs_info, "setting nodatacow");
444 }
445 }
446 btrfs_clear_opt(info->mount_opt, COMPRESS);
447 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
448 btrfs_set_opt(info->mount_opt, NODATACOW);
449 btrfs_set_opt(info->mount_opt, NODATASUM);
450 break;
451 case Opt_datacow:
452 btrfs_clear_and_info(root, NODATACOW,
453 "setting datacow");
454 break;
455 case Opt_compress_force:
456 case Opt_compress_force_type:
457 compress_force = true;
458 /* Fallthrough */
459 case Opt_compress:
460 case Opt_compress_type:
461 if (token == Opt_compress ||
462 token == Opt_compress_force ||
463 strcmp(args[0].from, "zlib") == 0) {
464 compress_type = "zlib";
465 info->compress_type = BTRFS_COMPRESS_ZLIB;
466 btrfs_set_opt(info->mount_opt, COMPRESS);
467 btrfs_clear_opt(info->mount_opt, NODATACOW);
468 btrfs_clear_opt(info->mount_opt, NODATASUM);
469 } else if (strcmp(args[0].from, "lzo") == 0) {
470 compress_type = "lzo";
471 info->compress_type = BTRFS_COMPRESS_LZO;
472 btrfs_set_opt(info->mount_opt, COMPRESS);
473 btrfs_clear_opt(info->mount_opt, NODATACOW);
474 btrfs_clear_opt(info->mount_opt, NODATASUM);
475 btrfs_set_fs_incompat(info, COMPRESS_LZO);
476 } else if (strncmp(args[0].from, "no", 2) == 0) {
477 compress_type = "no";
478 btrfs_clear_opt(info->mount_opt, COMPRESS);
479 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
480 compress_force = false;
481 } else {
482 ret = -EINVAL;
483 goto out;
484 }
485
486 if (compress_force) {
487 btrfs_set_and_info(root, FORCE_COMPRESS,
488 "force %s compression",
489 compress_type);
490 } else {
491 if (!btrfs_test_opt(root, COMPRESS))
492 btrfs_info(root->fs_info,
493 "btrfs: use %s compression",
494 compress_type);
495 /*
496 * If we remount from compress-force=xxx to
497 * compress=xxx, we need clear FORCE_COMPRESS
498 * flag, otherwise, there is no way for users
499 * to disable forcible compression separately.
500 */
501 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
502 }
503 break;
504 case Opt_ssd:
505 btrfs_set_and_info(root, SSD,
506 "use ssd allocation scheme");
507 break;
508 case Opt_ssd_spread:
509 btrfs_set_and_info(root, SSD_SPREAD,
510 "use spread ssd allocation scheme");
511 btrfs_set_opt(info->mount_opt, SSD);
512 break;
513 case Opt_nossd:
514 btrfs_set_and_info(root, NOSSD,
515 "not using ssd allocation scheme");
516 btrfs_clear_opt(info->mount_opt, SSD);
517 break;
518 case Opt_barrier:
519 btrfs_clear_and_info(root, NOBARRIER,
520 "turning on barriers");
521 break;
522 case Opt_nobarrier:
523 btrfs_set_and_info(root, NOBARRIER,
524 "turning off barriers");
525 break;
526 case Opt_thread_pool:
527 ret = match_int(&args[0], &intarg);
528 if (ret) {
529 goto out;
530 } else if (intarg > 0) {
531 info->thread_pool_size = intarg;
532 } else {
533 ret = -EINVAL;
534 goto out;
535 }
536 break;
537 case Opt_max_inline:
538 num = match_strdup(&args[0]);
539 if (num) {
540 info->max_inline = memparse(num, NULL);
541 kfree(num);
542
543 if (info->max_inline) {
544 info->max_inline = min_t(u64,
545 info->max_inline,
546 root->sectorsize);
547 }
548 btrfs_info(root->fs_info, "max_inline at %llu",
549 info->max_inline);
550 } else {
551 ret = -ENOMEM;
552 goto out;
553 }
554 break;
555 case Opt_alloc_start:
556 num = match_strdup(&args[0]);
557 if (num) {
558 mutex_lock(&info->chunk_mutex);
559 info->alloc_start = memparse(num, NULL);
560 mutex_unlock(&info->chunk_mutex);
561 kfree(num);
562 btrfs_info(root->fs_info, "allocations start at %llu",
563 info->alloc_start);
564 } else {
565 ret = -ENOMEM;
566 goto out;
567 }
568 break;
569 case Opt_acl:
570 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
571 root->fs_info->sb->s_flags |= MS_POSIXACL;
572 break;
573 #else
574 btrfs_err(root->fs_info,
575 "support for ACL not compiled in!");
576 ret = -EINVAL;
577 goto out;
578 #endif
579 case Opt_noacl:
580 root->fs_info->sb->s_flags &= ~MS_POSIXACL;
581 break;
582 case Opt_notreelog:
583 btrfs_set_and_info(root, NOTREELOG,
584 "disabling tree log");
585 break;
586 case Opt_treelog:
587 btrfs_clear_and_info(root, NOTREELOG,
588 "enabling tree log");
589 break;
590 case Opt_flushoncommit:
591 btrfs_set_and_info(root, FLUSHONCOMMIT,
592 "turning on flush-on-commit");
593 break;
594 case Opt_noflushoncommit:
595 btrfs_clear_and_info(root, FLUSHONCOMMIT,
596 "turning off flush-on-commit");
597 break;
598 case Opt_ratio:
599 ret = match_int(&args[0], &intarg);
600 if (ret) {
601 goto out;
602 } else if (intarg >= 0) {
603 info->metadata_ratio = intarg;
604 btrfs_info(root->fs_info, "metadata ratio %d",
605 info->metadata_ratio);
606 } else {
607 ret = -EINVAL;
608 goto out;
609 }
610 break;
611 case Opt_discard:
612 btrfs_set_and_info(root, DISCARD,
613 "turning on discard");
614 break;
615 case Opt_nodiscard:
616 btrfs_clear_and_info(root, DISCARD,
617 "turning off discard");
618 break;
619 case Opt_space_cache:
620 btrfs_set_and_info(root, SPACE_CACHE,
621 "enabling disk space caching");
622 break;
623 case Opt_rescan_uuid_tree:
624 btrfs_set_opt(info->mount_opt, RESCAN_UUID_TREE);
625 break;
626 case Opt_no_space_cache:
627 btrfs_clear_and_info(root, SPACE_CACHE,
628 "disabling disk space caching");
629 break;
630 case Opt_inode_cache:
631 btrfs_set_pending_and_info(info, INODE_MAP_CACHE,
632 "enabling inode map caching");
633 break;
634 case Opt_noinode_cache:
635 btrfs_clear_pending_and_info(info, INODE_MAP_CACHE,
636 "disabling inode map caching");
637 break;
638 case Opt_clear_cache:
639 btrfs_set_and_info(root, CLEAR_CACHE,
640 "force clearing of disk cache");
641 break;
642 case Opt_user_subvol_rm_allowed:
643 btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
644 break;
645 case Opt_enospc_debug:
646 btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
647 break;
648 case Opt_noenospc_debug:
649 btrfs_clear_opt(info->mount_opt, ENOSPC_DEBUG);
650 break;
651 case Opt_defrag:
652 btrfs_set_and_info(root, AUTO_DEFRAG,
653 "enabling auto defrag");
654 break;
655 case Opt_nodefrag:
656 btrfs_clear_and_info(root, AUTO_DEFRAG,
657 "disabling auto defrag");
658 break;
659 case Opt_recovery:
660 btrfs_info(root->fs_info, "enabling auto recovery");
661 btrfs_set_opt(info->mount_opt, RECOVERY);
662 break;
663 case Opt_skip_balance:
664 btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
665 break;
666 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
667 case Opt_check_integrity_including_extent_data:
668 btrfs_info(root->fs_info,
669 "enabling check integrity including extent data");
670 btrfs_set_opt(info->mount_opt,
671 CHECK_INTEGRITY_INCLUDING_EXTENT_DATA);
672 btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
673 break;
674 case Opt_check_integrity:
675 btrfs_info(root->fs_info, "enabling check integrity");
676 btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
677 break;
678 case Opt_check_integrity_print_mask:
679 ret = match_int(&args[0], &intarg);
680 if (ret) {
681 goto out;
682 } else if (intarg >= 0) {
683 info->check_integrity_print_mask = intarg;
684 btrfs_info(root->fs_info, "check_integrity_print_mask 0x%x",
685 info->check_integrity_print_mask);
686 } else {
687 ret = -EINVAL;
688 goto out;
689 }
690 break;
691 #else
692 case Opt_check_integrity_including_extent_data:
693 case Opt_check_integrity:
694 case Opt_check_integrity_print_mask:
695 btrfs_err(root->fs_info,
696 "support for check_integrity* not compiled in!");
697 ret = -EINVAL;
698 goto out;
699 #endif
700 case Opt_fatal_errors:
701 if (strcmp(args[0].from, "panic") == 0)
702 btrfs_set_opt(info->mount_opt,
703 PANIC_ON_FATAL_ERROR);
704 else if (strcmp(args[0].from, "bug") == 0)
705 btrfs_clear_opt(info->mount_opt,
706 PANIC_ON_FATAL_ERROR);
707 else {
708 ret = -EINVAL;
709 goto out;
710 }
711 break;
712 case Opt_commit_interval:
713 intarg = 0;
714 ret = match_int(&args[0], &intarg);
715 if (ret < 0) {
716 btrfs_err(root->fs_info, "invalid commit interval");
717 ret = -EINVAL;
718 goto out;
719 }
720 if (intarg > 0) {
721 if (intarg > 300) {
722 btrfs_warn(root->fs_info, "excessive commit interval %d",
723 intarg);
724 }
725 info->commit_interval = intarg;
726 } else {
727 btrfs_info(root->fs_info, "using default commit interval %ds",
728 BTRFS_DEFAULT_COMMIT_INTERVAL);
729 info->commit_interval = BTRFS_DEFAULT_COMMIT_INTERVAL;
730 }
731 break;
732 #ifdef CONFIG_BTRFS_DEBUG
733 case Opt_fragment_all:
734 btrfs_info(root->fs_info, "fragmenting all space");
735 btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
736 btrfs_set_opt(info->mount_opt, FRAGMENT_METADATA);
737 break;
738 case Opt_fragment_metadata:
739 btrfs_info(root->fs_info, "fragmenting metadata");
740 btrfs_set_opt(info->mount_opt,
741 FRAGMENT_METADATA);
742 break;
743 case Opt_fragment_data:
744 btrfs_info(root->fs_info, "fragmenting data");
745 btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
746 break;
747 #endif
748 case Opt_err:
749 btrfs_info(root->fs_info, "unrecognized mount option '%s'", p);
750 ret = -EINVAL;
751 goto out;
752 default:
753 break;
754 }
755 }
756 out:
757 if (!ret && btrfs_test_opt(root, SPACE_CACHE))
758 btrfs_info(root->fs_info, "disk space caching is enabled");
759 kfree(orig);
760 return ret;
761 }
762
763 /*
764 * Parse mount options that are required early in the mount process.
765 *
766 * All other options will be parsed on much later in the mount process and
767 * only when we need to allocate a new super block.
768 */
btrfs_parse_early_options(const char * options,fmode_t flags,void * holder,char ** subvol_name,u64 * subvol_objectid,struct btrfs_fs_devices ** fs_devices)769 static int btrfs_parse_early_options(const char *options, fmode_t flags,
770 void *holder, char **subvol_name, u64 *subvol_objectid,
771 struct btrfs_fs_devices **fs_devices)
772 {
773 substring_t args[MAX_OPT_ARGS];
774 char *device_name, *opts, *orig, *p;
775 char *num = NULL;
776 int error = 0;
777
778 if (!options)
779 return 0;
780
781 /*
782 * strsep changes the string, duplicate it because parse_options
783 * gets called twice
784 */
785 opts = kstrdup(options, GFP_KERNEL);
786 if (!opts)
787 return -ENOMEM;
788 orig = opts;
789
790 while ((p = strsep(&opts, ",")) != NULL) {
791 int token;
792 if (!*p)
793 continue;
794
795 token = match_token(p, tokens, args);
796 switch (token) {
797 case Opt_subvol:
798 kfree(*subvol_name);
799 *subvol_name = match_strdup(&args[0]);
800 if (!*subvol_name) {
801 error = -ENOMEM;
802 goto out;
803 }
804 break;
805 case Opt_subvolid:
806 num = match_strdup(&args[0]);
807 if (num) {
808 *subvol_objectid = memparse(num, NULL);
809 kfree(num);
810 /* we want the original fs_tree */
811 if (!*subvol_objectid)
812 *subvol_objectid =
813 BTRFS_FS_TREE_OBJECTID;
814 } else {
815 error = -EINVAL;
816 goto out;
817 }
818 break;
819 case Opt_subvolrootid:
820 printk(KERN_WARNING
821 "BTRFS: 'subvolrootid' mount option is deprecated and has "
822 "no effect\n");
823 break;
824 case Opt_device:
825 device_name = match_strdup(&args[0]);
826 if (!device_name) {
827 error = -ENOMEM;
828 goto out;
829 }
830 error = btrfs_scan_one_device(device_name,
831 flags, holder, fs_devices);
832 kfree(device_name);
833 if (error)
834 goto out;
835 break;
836 default:
837 break;
838 }
839 }
840
841 out:
842 kfree(orig);
843 return error;
844 }
845
btrfs_get_subvol_name_from_objectid(struct btrfs_fs_info * fs_info,u64 subvol_objectid)846 char *btrfs_get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
847 u64 subvol_objectid)
848 {
849 struct btrfs_root *root = fs_info->tree_root;
850 struct btrfs_root *fs_root;
851 struct btrfs_root_ref *root_ref;
852 struct btrfs_inode_ref *inode_ref;
853 struct btrfs_key key;
854 struct btrfs_path *path = NULL;
855 char *name = NULL, *ptr;
856 u64 dirid;
857 int len;
858 int ret;
859
860 path = btrfs_alloc_path();
861 if (!path) {
862 ret = -ENOMEM;
863 goto err;
864 }
865 path->leave_spinning = 1;
866
867 name = kmalloc(PATH_MAX, GFP_NOFS);
868 if (!name) {
869 ret = -ENOMEM;
870 goto err;
871 }
872 ptr = name + PATH_MAX - 1;
873 ptr[0] = '\0';
874
875 /*
876 * Walk up the subvolume trees in the tree of tree roots by root
877 * backrefs until we hit the top-level subvolume.
878 */
879 while (subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
880 key.objectid = subvol_objectid;
881 key.type = BTRFS_ROOT_BACKREF_KEY;
882 key.offset = (u64)-1;
883
884 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
885 if (ret < 0) {
886 goto err;
887 } else if (ret > 0) {
888 ret = btrfs_previous_item(root, path, subvol_objectid,
889 BTRFS_ROOT_BACKREF_KEY);
890 if (ret < 0) {
891 goto err;
892 } else if (ret > 0) {
893 ret = -ENOENT;
894 goto err;
895 }
896 }
897
898 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
899 subvol_objectid = key.offset;
900
901 root_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
902 struct btrfs_root_ref);
903 len = btrfs_root_ref_name_len(path->nodes[0], root_ref);
904 ptr -= len + 1;
905 if (ptr < name) {
906 ret = -ENAMETOOLONG;
907 goto err;
908 }
909 read_extent_buffer(path->nodes[0], ptr + 1,
910 (unsigned long)(root_ref + 1), len);
911 ptr[0] = '/';
912 dirid = btrfs_root_ref_dirid(path->nodes[0], root_ref);
913 btrfs_release_path(path);
914
915 key.objectid = subvol_objectid;
916 key.type = BTRFS_ROOT_ITEM_KEY;
917 key.offset = (u64)-1;
918 fs_root = btrfs_read_fs_root_no_name(fs_info, &key);
919 if (IS_ERR(fs_root)) {
920 ret = PTR_ERR(fs_root);
921 goto err;
922 }
923
924 /*
925 * Walk up the filesystem tree by inode refs until we hit the
926 * root directory.
927 */
928 while (dirid != BTRFS_FIRST_FREE_OBJECTID) {
929 key.objectid = dirid;
930 key.type = BTRFS_INODE_REF_KEY;
931 key.offset = (u64)-1;
932
933 ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0);
934 if (ret < 0) {
935 goto err;
936 } else if (ret > 0) {
937 ret = btrfs_previous_item(fs_root, path, dirid,
938 BTRFS_INODE_REF_KEY);
939 if (ret < 0) {
940 goto err;
941 } else if (ret > 0) {
942 ret = -ENOENT;
943 goto err;
944 }
945 }
946
947 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
948 dirid = key.offset;
949
950 inode_ref = btrfs_item_ptr(path->nodes[0],
951 path->slots[0],
952 struct btrfs_inode_ref);
953 len = btrfs_inode_ref_name_len(path->nodes[0],
954 inode_ref);
955 ptr -= len + 1;
956 if (ptr < name) {
957 ret = -ENAMETOOLONG;
958 goto err;
959 }
960 read_extent_buffer(path->nodes[0], ptr + 1,
961 (unsigned long)(inode_ref + 1), len);
962 ptr[0] = '/';
963 btrfs_release_path(path);
964 }
965 }
966
967 btrfs_free_path(path);
968 if (ptr == name + PATH_MAX - 1) {
969 name[0] = '/';
970 name[1] = '\0';
971 } else {
972 memmove(name, ptr, name + PATH_MAX - ptr);
973 }
974 return name;
975
976 err:
977 btrfs_free_path(path);
978 kfree(name);
979 return ERR_PTR(ret);
980 }
981
get_default_subvol_objectid(struct btrfs_fs_info * fs_info,u64 * objectid)982 static int get_default_subvol_objectid(struct btrfs_fs_info *fs_info, u64 *objectid)
983 {
984 struct btrfs_root *root = fs_info->tree_root;
985 struct btrfs_dir_item *di;
986 struct btrfs_path *path;
987 struct btrfs_key location;
988 u64 dir_id;
989
990 path = btrfs_alloc_path();
991 if (!path)
992 return -ENOMEM;
993 path->leave_spinning = 1;
994
995 /*
996 * Find the "default" dir item which points to the root item that we
997 * will mount by default if we haven't been given a specific subvolume
998 * to mount.
999 */
1000 dir_id = btrfs_super_root_dir(fs_info->super_copy);
1001 di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
1002 if (IS_ERR(di)) {
1003 btrfs_free_path(path);
1004 return PTR_ERR(di);
1005 }
1006 if (!di) {
1007 /*
1008 * Ok the default dir item isn't there. This is weird since
1009 * it's always been there, but don't freak out, just try and
1010 * mount the top-level subvolume.
1011 */
1012 btrfs_free_path(path);
1013 *objectid = BTRFS_FS_TREE_OBJECTID;
1014 return 0;
1015 }
1016
1017 btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
1018 btrfs_free_path(path);
1019 *objectid = location.objectid;
1020 return 0;
1021 }
1022
btrfs_fill_super(struct super_block * sb,struct btrfs_fs_devices * fs_devices,void * data,int silent)1023 static int btrfs_fill_super(struct super_block *sb,
1024 struct btrfs_fs_devices *fs_devices,
1025 void *data, int silent)
1026 {
1027 struct inode *inode;
1028 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1029 struct btrfs_key key;
1030 int err;
1031
1032 sb->s_maxbytes = MAX_LFS_FILESIZE;
1033 sb->s_magic = BTRFS_SUPER_MAGIC;
1034 sb->s_op = &btrfs_super_ops;
1035 sb->s_d_op = &btrfs_dentry_operations;
1036 sb->s_export_op = &btrfs_export_ops;
1037 sb->s_xattr = btrfs_xattr_handlers;
1038 sb->s_time_gran = 1;
1039 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
1040 sb->s_flags |= MS_POSIXACL;
1041 #endif
1042 sb->s_flags |= MS_I_VERSION;
1043 sb->s_iflags |= SB_I_CGROUPWB;
1044 err = open_ctree(sb, fs_devices, (char *)data);
1045 if (err) {
1046 printk(KERN_ERR "BTRFS: open_ctree failed\n");
1047 return err;
1048 }
1049
1050 key.objectid = BTRFS_FIRST_FREE_OBJECTID;
1051 key.type = BTRFS_INODE_ITEM_KEY;
1052 key.offset = 0;
1053 inode = btrfs_iget(sb, &key, fs_info->fs_root, NULL);
1054 if (IS_ERR(inode)) {
1055 err = PTR_ERR(inode);
1056 goto fail_close;
1057 }
1058
1059 sb->s_root = d_make_root(inode);
1060 if (!sb->s_root) {
1061 err = -ENOMEM;
1062 goto fail_close;
1063 }
1064
1065 save_mount_options(sb, data);
1066 cleancache_init_fs(sb);
1067 sb->s_flags |= MS_ACTIVE;
1068 return 0;
1069
1070 fail_close:
1071 close_ctree(fs_info->tree_root);
1072 return err;
1073 }
1074
btrfs_sync_fs(struct super_block * sb,int wait)1075 int btrfs_sync_fs(struct super_block *sb, int wait)
1076 {
1077 struct btrfs_trans_handle *trans;
1078 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1079 struct btrfs_root *root = fs_info->tree_root;
1080
1081 trace_btrfs_sync_fs(wait);
1082
1083 if (!wait) {
1084 filemap_flush(fs_info->btree_inode->i_mapping);
1085 return 0;
1086 }
1087
1088 btrfs_wait_ordered_roots(fs_info, -1);
1089
1090 trans = btrfs_attach_transaction_barrier(root);
1091 if (IS_ERR(trans)) {
1092 /* no transaction, don't bother */
1093 if (PTR_ERR(trans) == -ENOENT) {
1094 /*
1095 * Exit unless we have some pending changes
1096 * that need to go through commit
1097 */
1098 if (fs_info->pending_changes == 0)
1099 return 0;
1100 /*
1101 * A non-blocking test if the fs is frozen. We must not
1102 * start a new transaction here otherwise a deadlock
1103 * happens. The pending operations are delayed to the
1104 * next commit after thawing.
1105 */
1106 if (__sb_start_write(sb, SB_FREEZE_WRITE, false))
1107 __sb_end_write(sb, SB_FREEZE_WRITE);
1108 else
1109 return 0;
1110 trans = btrfs_start_transaction(root, 0);
1111 }
1112 if (IS_ERR(trans))
1113 return PTR_ERR(trans);
1114 }
1115 return btrfs_commit_transaction(trans, root);
1116 }
1117
btrfs_show_options(struct seq_file * seq,struct dentry * dentry)1118 static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
1119 {
1120 struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
1121 struct btrfs_root *root = info->tree_root;
1122 char *compress_type;
1123 const char *subvol_name;
1124
1125 if (btrfs_test_opt(root, DEGRADED))
1126 seq_puts(seq, ",degraded");
1127 if (btrfs_test_opt(root, NODATASUM))
1128 seq_puts(seq, ",nodatasum");
1129 if (btrfs_test_opt(root, NODATACOW))
1130 seq_puts(seq, ",nodatacow");
1131 if (btrfs_test_opt(root, NOBARRIER))
1132 seq_puts(seq, ",nobarrier");
1133 if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE)
1134 seq_printf(seq, ",max_inline=%llu", info->max_inline);
1135 if (info->alloc_start != 0)
1136 seq_printf(seq, ",alloc_start=%llu", info->alloc_start);
1137 if (info->thread_pool_size != min_t(unsigned long,
1138 num_online_cpus() + 2, 8))
1139 seq_printf(seq, ",thread_pool=%d", info->thread_pool_size);
1140 if (btrfs_test_opt(root, COMPRESS)) {
1141 if (info->compress_type == BTRFS_COMPRESS_ZLIB)
1142 compress_type = "zlib";
1143 else
1144 compress_type = "lzo";
1145 if (btrfs_test_opt(root, FORCE_COMPRESS))
1146 seq_printf(seq, ",compress-force=%s", compress_type);
1147 else
1148 seq_printf(seq, ",compress=%s", compress_type);
1149 }
1150 if (btrfs_test_opt(root, NOSSD))
1151 seq_puts(seq, ",nossd");
1152 if (btrfs_test_opt(root, SSD_SPREAD))
1153 seq_puts(seq, ",ssd_spread");
1154 else if (btrfs_test_opt(root, SSD))
1155 seq_puts(seq, ",ssd");
1156 if (btrfs_test_opt(root, NOTREELOG))
1157 seq_puts(seq, ",notreelog");
1158 if (btrfs_test_opt(root, FLUSHONCOMMIT))
1159 seq_puts(seq, ",flushoncommit");
1160 if (btrfs_test_opt(root, DISCARD))
1161 seq_puts(seq, ",discard");
1162 if (!(root->fs_info->sb->s_flags & MS_POSIXACL))
1163 seq_puts(seq, ",noacl");
1164 if (btrfs_test_opt(root, SPACE_CACHE))
1165 seq_puts(seq, ",space_cache");
1166 else
1167 seq_puts(seq, ",nospace_cache");
1168 if (btrfs_test_opt(root, RESCAN_UUID_TREE))
1169 seq_puts(seq, ",rescan_uuid_tree");
1170 if (btrfs_test_opt(root, CLEAR_CACHE))
1171 seq_puts(seq, ",clear_cache");
1172 if (btrfs_test_opt(root, USER_SUBVOL_RM_ALLOWED))
1173 seq_puts(seq, ",user_subvol_rm_allowed");
1174 if (btrfs_test_opt(root, ENOSPC_DEBUG))
1175 seq_puts(seq, ",enospc_debug");
1176 if (btrfs_test_opt(root, AUTO_DEFRAG))
1177 seq_puts(seq, ",autodefrag");
1178 if (btrfs_test_opt(root, INODE_MAP_CACHE))
1179 seq_puts(seq, ",inode_cache");
1180 if (btrfs_test_opt(root, SKIP_BALANCE))
1181 seq_puts(seq, ",skip_balance");
1182 if (btrfs_test_opt(root, RECOVERY))
1183 seq_puts(seq, ",recovery");
1184 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
1185 if (btrfs_test_opt(root, CHECK_INTEGRITY_INCLUDING_EXTENT_DATA))
1186 seq_puts(seq, ",check_int_data");
1187 else if (btrfs_test_opt(root, CHECK_INTEGRITY))
1188 seq_puts(seq, ",check_int");
1189 if (info->check_integrity_print_mask)
1190 seq_printf(seq, ",check_int_print_mask=%d",
1191 info->check_integrity_print_mask);
1192 #endif
1193 if (info->metadata_ratio)
1194 seq_printf(seq, ",metadata_ratio=%d",
1195 info->metadata_ratio);
1196 if (btrfs_test_opt(root, PANIC_ON_FATAL_ERROR))
1197 seq_puts(seq, ",fatal_errors=panic");
1198 if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL)
1199 seq_printf(seq, ",commit=%d", info->commit_interval);
1200 #ifdef CONFIG_BTRFS_DEBUG
1201 if (btrfs_test_opt(root, FRAGMENT_DATA))
1202 seq_puts(seq, ",fragment=data");
1203 if (btrfs_test_opt(root, FRAGMENT_METADATA))
1204 seq_puts(seq, ",fragment=metadata");
1205 #endif
1206 seq_printf(seq, ",subvolid=%llu",
1207 BTRFS_I(d_inode(dentry))->root->root_key.objectid);
1208 subvol_name = btrfs_get_subvol_name_from_objectid(info,
1209 BTRFS_I(d_inode(dentry))->root->root_key.objectid);
1210 if (!IS_ERR(subvol_name)) {
1211 seq_puts(seq, ",subvol=");
1212 seq_escape(seq, subvol_name, " \t\n\\");
1213 kfree(subvol_name);
1214 }
1215 return 0;
1216 }
1217
btrfs_test_super(struct super_block * s,void * data)1218 static int btrfs_test_super(struct super_block *s, void *data)
1219 {
1220 struct btrfs_fs_info *p = data;
1221 struct btrfs_fs_info *fs_info = btrfs_sb(s);
1222
1223 return fs_info->fs_devices == p->fs_devices;
1224 }
1225
btrfs_set_super(struct super_block * s,void * data)1226 static int btrfs_set_super(struct super_block *s, void *data)
1227 {
1228 int err = set_anon_super(s, data);
1229 if (!err)
1230 s->s_fs_info = data;
1231 return err;
1232 }
1233
1234 /*
1235 * subvolumes are identified by ino 256
1236 */
is_subvolume_inode(struct inode * inode)1237 static inline int is_subvolume_inode(struct inode *inode)
1238 {
1239 if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
1240 return 1;
1241 return 0;
1242 }
1243
1244 /*
1245 * This will add subvolid=0 to the argument string while removing any subvol=
1246 * and subvolid= arguments to make sure we get the top-level root for path
1247 * walking to the subvol we want.
1248 */
setup_root_args(char * args)1249 static char *setup_root_args(char *args)
1250 {
1251 char *buf, *dst, *sep;
1252
1253 if (!args)
1254 return kstrdup("subvolid=0", GFP_NOFS);
1255
1256 /* The worst case is that we add ",subvolid=0" to the end. */
1257 buf = dst = kmalloc(strlen(args) + strlen(",subvolid=0") + 1, GFP_NOFS);
1258 if (!buf)
1259 return NULL;
1260
1261 while (1) {
1262 sep = strchrnul(args, ',');
1263 if (!strstarts(args, "subvol=") &&
1264 !strstarts(args, "subvolid=")) {
1265 memcpy(dst, args, sep - args);
1266 dst += sep - args;
1267 *dst++ = ',';
1268 }
1269 if (*sep)
1270 args = sep + 1;
1271 else
1272 break;
1273 }
1274 strcpy(dst, "subvolid=0");
1275
1276 return buf;
1277 }
1278
mount_subvol(const char * subvol_name,u64 subvol_objectid,int flags,const char * device_name,char * data)1279 static struct dentry *mount_subvol(const char *subvol_name, u64 subvol_objectid,
1280 int flags, const char *device_name,
1281 char *data)
1282 {
1283 struct dentry *root;
1284 struct vfsmount *mnt = NULL;
1285 char *newargs;
1286 int ret;
1287
1288 newargs = setup_root_args(data);
1289 if (!newargs) {
1290 root = ERR_PTR(-ENOMEM);
1291 goto out;
1292 }
1293
1294 mnt = vfs_kern_mount(&btrfs_fs_type, flags, device_name, newargs);
1295 if (PTR_ERR_OR_ZERO(mnt) == -EBUSY) {
1296 if (flags & MS_RDONLY) {
1297 mnt = vfs_kern_mount(&btrfs_fs_type, flags & ~MS_RDONLY,
1298 device_name, newargs);
1299 } else {
1300 mnt = vfs_kern_mount(&btrfs_fs_type, flags | MS_RDONLY,
1301 device_name, newargs);
1302 if (IS_ERR(mnt)) {
1303 root = ERR_CAST(mnt);
1304 mnt = NULL;
1305 goto out;
1306 }
1307
1308 down_write(&mnt->mnt_sb->s_umount);
1309 ret = btrfs_remount(mnt->mnt_sb, &flags, NULL);
1310 up_write(&mnt->mnt_sb->s_umount);
1311 if (ret < 0) {
1312 root = ERR_PTR(ret);
1313 goto out;
1314 }
1315 }
1316 }
1317 if (IS_ERR(mnt)) {
1318 root = ERR_CAST(mnt);
1319 mnt = NULL;
1320 goto out;
1321 }
1322
1323 if (!subvol_name) {
1324 if (!subvol_objectid) {
1325 ret = get_default_subvol_objectid(btrfs_sb(mnt->mnt_sb),
1326 &subvol_objectid);
1327 if (ret) {
1328 root = ERR_PTR(ret);
1329 goto out;
1330 }
1331 }
1332 subvol_name = btrfs_get_subvol_name_from_objectid(
1333 btrfs_sb(mnt->mnt_sb), subvol_objectid);
1334 if (IS_ERR(subvol_name)) {
1335 root = ERR_CAST(subvol_name);
1336 subvol_name = NULL;
1337 goto out;
1338 }
1339
1340 }
1341
1342 root = mount_subtree(mnt, subvol_name);
1343 /* mount_subtree() drops our reference on the vfsmount. */
1344 mnt = NULL;
1345
1346 if (!IS_ERR(root)) {
1347 struct super_block *s = root->d_sb;
1348 struct inode *root_inode = d_inode(root);
1349 u64 root_objectid = BTRFS_I(root_inode)->root->root_key.objectid;
1350
1351 ret = 0;
1352 if (!is_subvolume_inode(root_inode)) {
1353 pr_err("BTRFS: '%s' is not a valid subvolume\n",
1354 subvol_name);
1355 ret = -EINVAL;
1356 }
1357 if (subvol_objectid && root_objectid != subvol_objectid) {
1358 /*
1359 * This will also catch a race condition where a
1360 * subvolume which was passed by ID is renamed and
1361 * another subvolume is renamed over the old location.
1362 */
1363 pr_err("BTRFS: subvol '%s' does not match subvolid %llu\n",
1364 subvol_name, subvol_objectid);
1365 ret = -EINVAL;
1366 }
1367 if (ret) {
1368 dput(root);
1369 root = ERR_PTR(ret);
1370 deactivate_locked_super(s);
1371 }
1372 }
1373
1374 out:
1375 mntput(mnt);
1376 kfree(newargs);
1377 kfree(subvol_name);
1378 return root;
1379 }
1380
parse_security_options(char * orig_opts,struct security_mnt_opts * sec_opts)1381 static int parse_security_options(char *orig_opts,
1382 struct security_mnt_opts *sec_opts)
1383 {
1384 char *secdata = NULL;
1385 int ret = 0;
1386
1387 secdata = alloc_secdata();
1388 if (!secdata)
1389 return -ENOMEM;
1390 ret = security_sb_copy_data(orig_opts, secdata);
1391 if (ret) {
1392 free_secdata(secdata);
1393 return ret;
1394 }
1395 ret = security_sb_parse_opts_str(secdata, sec_opts);
1396 free_secdata(secdata);
1397 return ret;
1398 }
1399
setup_security_options(struct btrfs_fs_info * fs_info,struct super_block * sb,struct security_mnt_opts * sec_opts)1400 static int setup_security_options(struct btrfs_fs_info *fs_info,
1401 struct super_block *sb,
1402 struct security_mnt_opts *sec_opts)
1403 {
1404 int ret = 0;
1405
1406 /*
1407 * Call security_sb_set_mnt_opts() to check whether new sec_opts
1408 * is valid.
1409 */
1410 ret = security_sb_set_mnt_opts(sb, sec_opts, 0, NULL);
1411 if (ret)
1412 return ret;
1413
1414 #ifdef CONFIG_SECURITY
1415 if (!fs_info->security_opts.num_mnt_opts) {
1416 /* first time security setup, copy sec_opts to fs_info */
1417 memcpy(&fs_info->security_opts, sec_opts, sizeof(*sec_opts));
1418 } else {
1419 /*
1420 * Since SELinux(the only one supports security_mnt_opts) does
1421 * NOT support changing context during remount/mount same sb,
1422 * This must be the same or part of the same security options,
1423 * just free it.
1424 */
1425 security_free_mnt_opts(sec_opts);
1426 }
1427 #endif
1428 return ret;
1429 }
1430
1431 /*
1432 * Find a superblock for the given device / mount point.
1433 *
1434 * Note: This is based on get_sb_bdev from fs/super.c with a few additions
1435 * for multiple device setup. Make sure to keep it in sync.
1436 */
btrfs_mount(struct file_system_type * fs_type,int flags,const char * device_name,void * data)1437 static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
1438 const char *device_name, void *data)
1439 {
1440 struct block_device *bdev = NULL;
1441 struct super_block *s;
1442 struct btrfs_fs_devices *fs_devices = NULL;
1443 struct btrfs_fs_info *fs_info = NULL;
1444 struct security_mnt_opts new_sec_opts;
1445 fmode_t mode = FMODE_READ;
1446 char *subvol_name = NULL;
1447 u64 subvol_objectid = 0;
1448 int error = 0;
1449
1450 if (!(flags & MS_RDONLY))
1451 mode |= FMODE_WRITE;
1452
1453 error = btrfs_parse_early_options(data, mode, fs_type,
1454 &subvol_name, &subvol_objectid,
1455 &fs_devices);
1456 if (error) {
1457 kfree(subvol_name);
1458 return ERR_PTR(error);
1459 }
1460
1461 if (subvol_name || subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
1462 /* mount_subvol() will free subvol_name. */
1463 return mount_subvol(subvol_name, subvol_objectid, flags,
1464 device_name, data);
1465 }
1466
1467 security_init_mnt_opts(&new_sec_opts);
1468 if (data) {
1469 error = parse_security_options(data, &new_sec_opts);
1470 if (error)
1471 return ERR_PTR(error);
1472 }
1473
1474 error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices);
1475 if (error)
1476 goto error_sec_opts;
1477
1478 /*
1479 * Setup a dummy root and fs_info for test/set super. This is because
1480 * we don't actually fill this stuff out until open_ctree, but we need
1481 * it for searching for existing supers, so this lets us do that and
1482 * then open_ctree will properly initialize everything later.
1483 */
1484 fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_NOFS);
1485 if (!fs_info) {
1486 error = -ENOMEM;
1487 goto error_sec_opts;
1488 }
1489
1490 fs_info->fs_devices = fs_devices;
1491
1492 fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
1493 fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
1494 security_init_mnt_opts(&fs_info->security_opts);
1495 if (!fs_info->super_copy || !fs_info->super_for_commit) {
1496 error = -ENOMEM;
1497 goto error_fs_info;
1498 }
1499
1500 error = btrfs_open_devices(fs_devices, mode, fs_type);
1501 if (error)
1502 goto error_fs_info;
1503
1504 if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
1505 error = -EACCES;
1506 goto error_close_devices;
1507 }
1508
1509 bdev = fs_devices->latest_bdev;
1510 s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | MS_NOSEC,
1511 fs_info);
1512 if (IS_ERR(s)) {
1513 error = PTR_ERR(s);
1514 goto error_close_devices;
1515 }
1516
1517 if (s->s_root) {
1518 btrfs_close_devices(fs_devices);
1519 free_fs_info(fs_info);
1520 if ((flags ^ s->s_flags) & MS_RDONLY)
1521 error = -EBUSY;
1522 } else {
1523 char b[BDEVNAME_SIZE];
1524
1525 strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
1526 btrfs_sb(s)->bdev_holder = fs_type;
1527 error = btrfs_fill_super(s, fs_devices, data,
1528 flags & MS_SILENT ? 1 : 0);
1529 }
1530 if (error) {
1531 deactivate_locked_super(s);
1532 goto error_sec_opts;
1533 }
1534
1535 fs_info = btrfs_sb(s);
1536 error = setup_security_options(fs_info, s, &new_sec_opts);
1537 if (error) {
1538 deactivate_locked_super(s);
1539 goto error_sec_opts;
1540 }
1541
1542 return dget(s->s_root);
1543
1544 error_close_devices:
1545 btrfs_close_devices(fs_devices);
1546 error_fs_info:
1547 free_fs_info(fs_info);
1548 error_sec_opts:
1549 security_free_mnt_opts(&new_sec_opts);
1550 return ERR_PTR(error);
1551 }
1552
btrfs_resize_thread_pool(struct btrfs_fs_info * fs_info,int new_pool_size,int old_pool_size)1553 static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
1554 int new_pool_size, int old_pool_size)
1555 {
1556 if (new_pool_size == old_pool_size)
1557 return;
1558
1559 fs_info->thread_pool_size = new_pool_size;
1560
1561 btrfs_info(fs_info, "resize thread pool %d -> %d",
1562 old_pool_size, new_pool_size);
1563
1564 btrfs_workqueue_set_max(fs_info->workers, new_pool_size);
1565 btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size);
1566 btrfs_workqueue_set_max(fs_info->submit_workers, new_pool_size);
1567 btrfs_workqueue_set_max(fs_info->caching_workers, new_pool_size);
1568 btrfs_workqueue_set_max(fs_info->endio_workers, new_pool_size);
1569 btrfs_workqueue_set_max(fs_info->endio_meta_workers, new_pool_size);
1570 btrfs_workqueue_set_max(fs_info->endio_meta_write_workers,
1571 new_pool_size);
1572 btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size);
1573 btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
1574 btrfs_workqueue_set_max(fs_info->delayed_workers, new_pool_size);
1575 btrfs_workqueue_set_max(fs_info->readahead_workers, new_pool_size);
1576 btrfs_workqueue_set_max(fs_info->scrub_wr_completion_workers,
1577 new_pool_size);
1578 }
1579
btrfs_remount_prepare(struct btrfs_fs_info * fs_info)1580 static inline void btrfs_remount_prepare(struct btrfs_fs_info *fs_info)
1581 {
1582 set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1583 }
1584
btrfs_remount_begin(struct btrfs_fs_info * fs_info,unsigned long old_opts,int flags)1585 static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info,
1586 unsigned long old_opts, int flags)
1587 {
1588 if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1589 (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1590 (flags & MS_RDONLY))) {
1591 /* wait for any defraggers to finish */
1592 wait_event(fs_info->transaction_wait,
1593 (atomic_read(&fs_info->defrag_running) == 0));
1594 if (flags & MS_RDONLY)
1595 sync_filesystem(fs_info->sb);
1596 }
1597 }
1598
btrfs_remount_cleanup(struct btrfs_fs_info * fs_info,unsigned long old_opts)1599 static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
1600 unsigned long old_opts)
1601 {
1602 /*
1603 * We need cleanup all defragable inodes if the autodefragment is
1604 * close or the fs is R/O.
1605 */
1606 if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1607 (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1608 (fs_info->sb->s_flags & MS_RDONLY))) {
1609 btrfs_cleanup_defrag_inodes(fs_info);
1610 }
1611
1612 clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1613 }
1614
btrfs_remount(struct super_block * sb,int * flags,char * data)1615 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
1616 {
1617 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1618 struct btrfs_root *root = fs_info->tree_root;
1619 unsigned old_flags = sb->s_flags;
1620 unsigned long old_opts = fs_info->mount_opt;
1621 unsigned long old_compress_type = fs_info->compress_type;
1622 u64 old_max_inline = fs_info->max_inline;
1623 u64 old_alloc_start = fs_info->alloc_start;
1624 int old_thread_pool_size = fs_info->thread_pool_size;
1625 unsigned int old_metadata_ratio = fs_info->metadata_ratio;
1626 int ret;
1627
1628 sync_filesystem(sb);
1629 btrfs_remount_prepare(fs_info);
1630
1631 if (data) {
1632 struct security_mnt_opts new_sec_opts;
1633
1634 security_init_mnt_opts(&new_sec_opts);
1635 ret = parse_security_options(data, &new_sec_opts);
1636 if (ret)
1637 goto restore;
1638 ret = setup_security_options(fs_info, sb,
1639 &new_sec_opts);
1640 if (ret) {
1641 security_free_mnt_opts(&new_sec_opts);
1642 goto restore;
1643 }
1644 }
1645
1646 ret = btrfs_parse_options(root, data);
1647 if (ret) {
1648 ret = -EINVAL;
1649 goto restore;
1650 }
1651
1652 btrfs_remount_begin(fs_info, old_opts, *flags);
1653 btrfs_resize_thread_pool(fs_info,
1654 fs_info->thread_pool_size, old_thread_pool_size);
1655
1656 if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1657 goto out;
1658
1659 if (*flags & MS_RDONLY) {
1660 /*
1661 * this also happens on 'umount -rf' or on shutdown, when
1662 * the filesystem is busy.
1663 */
1664 cancel_work_sync(&fs_info->async_reclaim_work);
1665
1666 /* wait for the uuid_scan task to finish */
1667 down(&fs_info->uuid_tree_rescan_sem);
1668 /* avoid complains from lockdep et al. */
1669 up(&fs_info->uuid_tree_rescan_sem);
1670
1671 sb->s_flags |= MS_RDONLY;
1672
1673 /*
1674 * Setting MS_RDONLY will put the cleaner thread to
1675 * sleep at the next loop if it's already active.
1676 * If it's already asleep, we'll leave unused block
1677 * groups on disk until we're mounted read-write again
1678 * unless we clean them up here.
1679 */
1680 btrfs_delete_unused_bgs(fs_info);
1681
1682 btrfs_dev_replace_suspend_for_unmount(fs_info);
1683 btrfs_scrub_cancel(fs_info);
1684 btrfs_pause_balance(fs_info);
1685
1686 ret = btrfs_commit_super(root);
1687 if (ret)
1688 goto restore;
1689 } else {
1690 if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state)) {
1691 btrfs_err(fs_info,
1692 "Remounting read-write after error is not allowed");
1693 ret = -EINVAL;
1694 goto restore;
1695 }
1696 if (fs_info->fs_devices->rw_devices == 0) {
1697 ret = -EACCES;
1698 goto restore;
1699 }
1700
1701 if (fs_info->fs_devices->missing_devices >
1702 fs_info->num_tolerated_disk_barrier_failures &&
1703 !(*flags & MS_RDONLY)) {
1704 btrfs_warn(fs_info,
1705 "too many missing devices, writeable remount is not allowed");
1706 ret = -EACCES;
1707 goto restore;
1708 }
1709
1710 if (btrfs_super_log_root(fs_info->super_copy) != 0) {
1711 btrfs_warn(fs_info,
1712 "mount required to replay tree-log, cannot remount read-write");
1713 ret = -EINVAL;
1714 goto restore;
1715 }
1716
1717 ret = btrfs_cleanup_fs_roots(fs_info);
1718 if (ret)
1719 goto restore;
1720
1721 /* recover relocation */
1722 mutex_lock(&fs_info->cleaner_mutex);
1723 ret = btrfs_recover_relocation(root);
1724 mutex_unlock(&fs_info->cleaner_mutex);
1725 if (ret)
1726 goto restore;
1727
1728 ret = btrfs_resume_balance_async(fs_info);
1729 if (ret)
1730 goto restore;
1731
1732 ret = btrfs_resume_dev_replace_async(fs_info);
1733 if (ret) {
1734 btrfs_warn(fs_info, "failed to resume dev_replace");
1735 goto restore;
1736 }
1737
1738 btrfs_qgroup_rescan_resume(fs_info);
1739
1740 if (!fs_info->uuid_root) {
1741 btrfs_info(fs_info, "creating UUID tree");
1742 ret = btrfs_create_uuid_tree(fs_info);
1743 if (ret) {
1744 btrfs_warn(fs_info, "failed to create the UUID tree %d", ret);
1745 goto restore;
1746 }
1747 }
1748 sb->s_flags &= ~MS_RDONLY;
1749 }
1750 out:
1751 wake_up_process(fs_info->transaction_kthread);
1752 btrfs_remount_cleanup(fs_info, old_opts);
1753 return 0;
1754
1755 restore:
1756 /* We've hit an error - don't reset MS_RDONLY */
1757 if (sb->s_flags & MS_RDONLY)
1758 old_flags |= MS_RDONLY;
1759 sb->s_flags = old_flags;
1760 fs_info->mount_opt = old_opts;
1761 fs_info->compress_type = old_compress_type;
1762 fs_info->max_inline = old_max_inline;
1763 mutex_lock(&fs_info->chunk_mutex);
1764 fs_info->alloc_start = old_alloc_start;
1765 mutex_unlock(&fs_info->chunk_mutex);
1766 btrfs_resize_thread_pool(fs_info,
1767 old_thread_pool_size, fs_info->thread_pool_size);
1768 fs_info->metadata_ratio = old_metadata_ratio;
1769 btrfs_remount_cleanup(fs_info, old_opts);
1770 return ret;
1771 }
1772
1773 /* Used to sort the devices by max_avail(descending sort) */
btrfs_cmp_device_free_bytes(const void * dev_info1,const void * dev_info2)1774 static int btrfs_cmp_device_free_bytes(const void *dev_info1,
1775 const void *dev_info2)
1776 {
1777 if (((struct btrfs_device_info *)dev_info1)->max_avail >
1778 ((struct btrfs_device_info *)dev_info2)->max_avail)
1779 return -1;
1780 else if (((struct btrfs_device_info *)dev_info1)->max_avail <
1781 ((struct btrfs_device_info *)dev_info2)->max_avail)
1782 return 1;
1783 else
1784 return 0;
1785 }
1786
1787 /*
1788 * sort the devices by max_avail, in which max free extent size of each device
1789 * is stored.(Descending Sort)
1790 */
btrfs_descending_sort_devices(struct btrfs_device_info * devices,size_t nr_devices)1791 static inline void btrfs_descending_sort_devices(
1792 struct btrfs_device_info *devices,
1793 size_t nr_devices)
1794 {
1795 sort(devices, nr_devices, sizeof(struct btrfs_device_info),
1796 btrfs_cmp_device_free_bytes, NULL);
1797 }
1798
1799 /*
1800 * The helper to calc the free space on the devices that can be used to store
1801 * file data.
1802 */
btrfs_calc_avail_data_space(struct btrfs_root * root,u64 * free_bytes)1803 static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes)
1804 {
1805 struct btrfs_fs_info *fs_info = root->fs_info;
1806 struct btrfs_device_info *devices_info;
1807 struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
1808 struct btrfs_device *device;
1809 u64 skip_space;
1810 u64 type;
1811 u64 avail_space;
1812 u64 used_space;
1813 u64 min_stripe_size;
1814 int min_stripes = 1, num_stripes = 1;
1815 int i = 0, nr_devices;
1816 int ret;
1817
1818 /*
1819 * We aren't under the device list lock, so this is racey-ish, but good
1820 * enough for our purposes.
1821 */
1822 nr_devices = fs_info->fs_devices->open_devices;
1823 if (!nr_devices) {
1824 smp_mb();
1825 nr_devices = fs_info->fs_devices->open_devices;
1826 ASSERT(nr_devices);
1827 if (!nr_devices) {
1828 *free_bytes = 0;
1829 return 0;
1830 }
1831 }
1832
1833 devices_info = kmalloc_array(nr_devices, sizeof(*devices_info),
1834 GFP_NOFS);
1835 if (!devices_info)
1836 return -ENOMEM;
1837
1838 /* calc min stripe number for data space alloction */
1839 type = btrfs_get_alloc_profile(root, 1);
1840 if (type & BTRFS_BLOCK_GROUP_RAID0) {
1841 min_stripes = 2;
1842 num_stripes = nr_devices;
1843 } else if (type & BTRFS_BLOCK_GROUP_RAID1) {
1844 min_stripes = 2;
1845 num_stripes = 2;
1846 } else if (type & BTRFS_BLOCK_GROUP_RAID10) {
1847 min_stripes = 4;
1848 num_stripes = 4;
1849 }
1850
1851 if (type & BTRFS_BLOCK_GROUP_DUP)
1852 min_stripe_size = 2 * BTRFS_STRIPE_LEN;
1853 else
1854 min_stripe_size = BTRFS_STRIPE_LEN;
1855
1856 if (fs_info->alloc_start)
1857 mutex_lock(&fs_devices->device_list_mutex);
1858 rcu_read_lock();
1859 list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
1860 if (!device->in_fs_metadata || !device->bdev ||
1861 device->is_tgtdev_for_dev_replace)
1862 continue;
1863
1864 if (i >= nr_devices)
1865 break;
1866
1867 avail_space = device->total_bytes - device->bytes_used;
1868
1869 /* align with stripe_len */
1870 avail_space = div_u64(avail_space, BTRFS_STRIPE_LEN);
1871 avail_space *= BTRFS_STRIPE_LEN;
1872
1873 /*
1874 * In order to avoid overwritting the superblock on the drive,
1875 * btrfs starts at an offset of at least 1MB when doing chunk
1876 * allocation.
1877 */
1878 skip_space = 1024 * 1024;
1879
1880 /* user can set the offset in fs_info->alloc_start. */
1881 if (fs_info->alloc_start &&
1882 fs_info->alloc_start + BTRFS_STRIPE_LEN <=
1883 device->total_bytes) {
1884 rcu_read_unlock();
1885 skip_space = max(fs_info->alloc_start, skip_space);
1886
1887 /*
1888 * btrfs can not use the free space in
1889 * [0, skip_space - 1], we must subtract it from the
1890 * total. In order to implement it, we account the used
1891 * space in this range first.
1892 */
1893 ret = btrfs_account_dev_extents_size(device, 0,
1894 skip_space - 1,
1895 &used_space);
1896 if (ret) {
1897 kfree(devices_info);
1898 mutex_unlock(&fs_devices->device_list_mutex);
1899 return ret;
1900 }
1901
1902 rcu_read_lock();
1903
1904 /* calc the free space in [0, skip_space - 1] */
1905 skip_space -= used_space;
1906 }
1907
1908 /*
1909 * we can use the free space in [0, skip_space - 1], subtract
1910 * it from the total.
1911 */
1912 if (avail_space && avail_space >= skip_space)
1913 avail_space -= skip_space;
1914 else
1915 avail_space = 0;
1916
1917 if (avail_space < min_stripe_size)
1918 continue;
1919
1920 devices_info[i].dev = device;
1921 devices_info[i].max_avail = avail_space;
1922
1923 i++;
1924 }
1925 rcu_read_unlock();
1926 if (fs_info->alloc_start)
1927 mutex_unlock(&fs_devices->device_list_mutex);
1928
1929 nr_devices = i;
1930
1931 btrfs_descending_sort_devices(devices_info, nr_devices);
1932
1933 i = nr_devices - 1;
1934 avail_space = 0;
1935 while (nr_devices >= min_stripes) {
1936 if (num_stripes > nr_devices)
1937 num_stripes = nr_devices;
1938
1939 if (devices_info[i].max_avail >= min_stripe_size) {
1940 int j;
1941 u64 alloc_size;
1942
1943 avail_space += devices_info[i].max_avail * num_stripes;
1944 alloc_size = devices_info[i].max_avail;
1945 for (j = i + 1 - num_stripes; j <= i; j++)
1946 devices_info[j].max_avail -= alloc_size;
1947 }
1948 i--;
1949 nr_devices--;
1950 }
1951
1952 kfree(devices_info);
1953 *free_bytes = avail_space;
1954 return 0;
1955 }
1956
1957 /*
1958 * Calculate numbers for 'df', pessimistic in case of mixed raid profiles.
1959 *
1960 * If there's a redundant raid level at DATA block groups, use the respective
1961 * multiplier to scale the sizes.
1962 *
1963 * Unused device space usage is based on simulating the chunk allocator
1964 * algorithm that respects the device sizes, order of allocations and the
1965 * 'alloc_start' value, this is a close approximation of the actual use but
1966 * there are other factors that may change the result (like a new metadata
1967 * chunk).
1968 *
1969 * If metadata is exhausted, f_bavail will be 0.
1970 *
1971 * FIXME: not accurate for mixed block groups, total and free/used are ok,
1972 * available appears slightly larger.
1973 */
btrfs_statfs(struct dentry * dentry,struct kstatfs * buf)1974 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
1975 {
1976 struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
1977 struct btrfs_super_block *disk_super = fs_info->super_copy;
1978 struct list_head *head = &fs_info->space_info;
1979 struct btrfs_space_info *found;
1980 u64 total_used = 0;
1981 u64 total_free_data = 0;
1982 u64 total_free_meta = 0;
1983 int bits = dentry->d_sb->s_blocksize_bits;
1984 __be32 *fsid = (__be32 *)fs_info->fsid;
1985 unsigned factor = 1;
1986 struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
1987 int ret;
1988 u64 thresh = 0;
1989 int mixed = 0;
1990
1991 /*
1992 * holding chunk_muext to avoid allocating new chunks, holding
1993 * device_list_mutex to avoid the device being removed
1994 */
1995 rcu_read_lock();
1996 list_for_each_entry_rcu(found, head, list) {
1997 if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
1998 int i;
1999
2000 total_free_data += found->disk_total - found->disk_used;
2001 total_free_data -=
2002 btrfs_account_ro_block_groups_free_space(found);
2003
2004 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
2005 if (!list_empty(&found->block_groups[i])) {
2006 switch (i) {
2007 case BTRFS_RAID_DUP:
2008 case BTRFS_RAID_RAID1:
2009 case BTRFS_RAID_RAID10:
2010 factor = 2;
2011 }
2012 }
2013 }
2014 }
2015
2016 /*
2017 * Metadata in mixed block goup profiles are accounted in data
2018 */
2019 if (!mixed && found->flags & BTRFS_BLOCK_GROUP_METADATA) {
2020 if (found->flags & BTRFS_BLOCK_GROUP_DATA)
2021 mixed = 1;
2022 else
2023 total_free_meta += found->disk_total -
2024 found->disk_used;
2025 }
2026
2027 total_used += found->disk_used;
2028 }
2029
2030 rcu_read_unlock();
2031
2032 buf->f_blocks = div_u64(btrfs_super_total_bytes(disk_super), factor);
2033 buf->f_blocks >>= bits;
2034 buf->f_bfree = buf->f_blocks - (div_u64(total_used, factor) >> bits);
2035
2036 /* Account global block reserve as used, it's in logical size already */
2037 spin_lock(&block_rsv->lock);
2038 buf->f_bfree -= block_rsv->size >> bits;
2039 spin_unlock(&block_rsv->lock);
2040
2041 buf->f_bavail = div_u64(total_free_data, factor);
2042 ret = btrfs_calc_avail_data_space(fs_info->tree_root, &total_free_data);
2043 if (ret)
2044 return ret;
2045 buf->f_bavail += div_u64(total_free_data, factor);
2046 buf->f_bavail = buf->f_bavail >> bits;
2047
2048 /*
2049 * We calculate the remaining metadata space minus global reserve. If
2050 * this is (supposedly) smaller than zero, there's no space. But this
2051 * does not hold in practice, the exhausted state happens where's still
2052 * some positive delta. So we apply some guesswork and compare the
2053 * delta to a 4M threshold. (Practically observed delta was ~2M.)
2054 *
2055 * We probably cannot calculate the exact threshold value because this
2056 * depends on the internal reservations requested by various
2057 * operations, so some operations that consume a few metadata will
2058 * succeed even if the Avail is zero. But this is better than the other
2059 * way around.
2060 */
2061 thresh = 4 * 1024 * 1024;
2062
2063 /*
2064 * We only want to claim there's no available space if we can no longer
2065 * allocate chunks for our metadata profile and our global reserve will
2066 * not fit in the free metadata space. If we aren't ->full then we
2067 * still can allocate chunks and thus are fine using the currently
2068 * calculated f_bavail.
2069 */
2070 if (!mixed && block_rsv->space_info->full &&
2071 total_free_meta - thresh < block_rsv->size)
2072 buf->f_bavail = 0;
2073
2074 buf->f_type = BTRFS_SUPER_MAGIC;
2075 buf->f_bsize = dentry->d_sb->s_blocksize;
2076 buf->f_namelen = BTRFS_NAME_LEN;
2077
2078 /* We treat it as constant endianness (it doesn't matter _which_)
2079 because we want the fsid to come out the same whether mounted
2080 on a big-endian or little-endian host */
2081 buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
2082 buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
2083 /* Mask in the root object ID too, to disambiguate subvols */
2084 buf->f_fsid.val[0] ^= BTRFS_I(d_inode(dentry))->root->objectid >> 32;
2085 buf->f_fsid.val[1] ^= BTRFS_I(d_inode(dentry))->root->objectid;
2086
2087 return 0;
2088 }
2089
btrfs_kill_super(struct super_block * sb)2090 static void btrfs_kill_super(struct super_block *sb)
2091 {
2092 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2093 kill_anon_super(sb);
2094 free_fs_info(fs_info);
2095 }
2096
2097 static struct file_system_type btrfs_fs_type = {
2098 .owner = THIS_MODULE,
2099 .name = "btrfs",
2100 .mount = btrfs_mount,
2101 .kill_sb = btrfs_kill_super,
2102 .fs_flags = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,
2103 };
2104 MODULE_ALIAS_FS("btrfs");
2105
btrfs_control_open(struct inode * inode,struct file * file)2106 static int btrfs_control_open(struct inode *inode, struct file *file)
2107 {
2108 /*
2109 * The control file's private_data is used to hold the
2110 * transaction when it is started and is used to keep
2111 * track of whether a transaction is already in progress.
2112 */
2113 file->private_data = NULL;
2114 return 0;
2115 }
2116
2117 /*
2118 * used by btrfsctl to scan devices when no FS is mounted
2119 */
btrfs_control_ioctl(struct file * file,unsigned int cmd,unsigned long arg)2120 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
2121 unsigned long arg)
2122 {
2123 struct btrfs_ioctl_vol_args *vol;
2124 struct btrfs_fs_devices *fs_devices;
2125 int ret = -ENOTTY;
2126
2127 if (!capable(CAP_SYS_ADMIN))
2128 return -EPERM;
2129
2130 vol = memdup_user((void __user *)arg, sizeof(*vol));
2131 if (IS_ERR(vol))
2132 return PTR_ERR(vol);
2133 vol->name[BTRFS_PATH_NAME_MAX] = '\0';
2134
2135 switch (cmd) {
2136 case BTRFS_IOC_SCAN_DEV:
2137 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
2138 &btrfs_fs_type, &fs_devices);
2139 break;
2140 case BTRFS_IOC_DEVICES_READY:
2141 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
2142 &btrfs_fs_type, &fs_devices);
2143 if (ret)
2144 break;
2145 ret = !(fs_devices->num_devices == fs_devices->total_devices);
2146 break;
2147 }
2148
2149 kfree(vol);
2150 return ret;
2151 }
2152
btrfs_freeze(struct super_block * sb)2153 static int btrfs_freeze(struct super_block *sb)
2154 {
2155 struct btrfs_trans_handle *trans;
2156 struct btrfs_root *root = btrfs_sb(sb)->tree_root;
2157
2158 trans = btrfs_attach_transaction_barrier(root);
2159 if (IS_ERR(trans)) {
2160 /* no transaction, don't bother */
2161 if (PTR_ERR(trans) == -ENOENT)
2162 return 0;
2163 return PTR_ERR(trans);
2164 }
2165 return btrfs_commit_transaction(trans, root);
2166 }
2167
btrfs_show_devname(struct seq_file * m,struct dentry * root)2168 static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
2169 {
2170 struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
2171 struct btrfs_fs_devices *cur_devices;
2172 struct btrfs_device *dev, *first_dev = NULL;
2173 struct list_head *head;
2174 struct rcu_string *name;
2175
2176 mutex_lock(&fs_info->fs_devices->device_list_mutex);
2177 cur_devices = fs_info->fs_devices;
2178 while (cur_devices) {
2179 head = &cur_devices->devices;
2180 list_for_each_entry(dev, head, dev_list) {
2181 if (dev->missing)
2182 continue;
2183 if (!dev->name)
2184 continue;
2185 if (!first_dev || dev->devid < first_dev->devid)
2186 first_dev = dev;
2187 }
2188 cur_devices = cur_devices->seed;
2189 }
2190
2191 if (first_dev) {
2192 rcu_read_lock();
2193 name = rcu_dereference(first_dev->name);
2194 seq_escape(m, name->str, " \t\n\\");
2195 rcu_read_unlock();
2196 } else {
2197 WARN_ON(1);
2198 }
2199 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2200 return 0;
2201 }
2202
2203 static const struct super_operations btrfs_super_ops = {
2204 .drop_inode = btrfs_drop_inode,
2205 .evict_inode = btrfs_evict_inode,
2206 .put_super = btrfs_put_super,
2207 .sync_fs = btrfs_sync_fs,
2208 .show_options = btrfs_show_options,
2209 .show_devname = btrfs_show_devname,
2210 .write_inode = btrfs_write_inode,
2211 .alloc_inode = btrfs_alloc_inode,
2212 .destroy_inode = btrfs_destroy_inode,
2213 .statfs = btrfs_statfs,
2214 .remount_fs = btrfs_remount,
2215 .freeze_fs = btrfs_freeze,
2216 };
2217
2218 static const struct file_operations btrfs_ctl_fops = {
2219 .open = btrfs_control_open,
2220 .unlocked_ioctl = btrfs_control_ioctl,
2221 .compat_ioctl = btrfs_control_ioctl,
2222 .owner = THIS_MODULE,
2223 .llseek = noop_llseek,
2224 };
2225
2226 static struct miscdevice btrfs_misc = {
2227 .minor = BTRFS_MINOR,
2228 .name = "btrfs-control",
2229 .fops = &btrfs_ctl_fops
2230 };
2231
2232 MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
2233 MODULE_ALIAS("devname:btrfs-control");
2234
btrfs_interface_init(void)2235 static int btrfs_interface_init(void)
2236 {
2237 return misc_register(&btrfs_misc);
2238 }
2239
btrfs_interface_exit(void)2240 static void btrfs_interface_exit(void)
2241 {
2242 misc_deregister(&btrfs_misc);
2243 }
2244
btrfs_print_info(void)2245 static void btrfs_print_info(void)
2246 {
2247 printk(KERN_INFO "Btrfs loaded"
2248 #ifdef CONFIG_BTRFS_DEBUG
2249 ", debug=on"
2250 #endif
2251 #ifdef CONFIG_BTRFS_ASSERT
2252 ", assert=on"
2253 #endif
2254 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
2255 ", integrity-checker=on"
2256 #endif
2257 "\n");
2258 }
2259
btrfs_run_sanity_tests(void)2260 static int btrfs_run_sanity_tests(void)
2261 {
2262 int ret;
2263
2264 ret = btrfs_init_test_fs();
2265 if (ret)
2266 return ret;
2267
2268 ret = btrfs_test_free_space_cache();
2269 if (ret)
2270 goto out;
2271 ret = btrfs_test_extent_buffer_operations();
2272 if (ret)
2273 goto out;
2274 ret = btrfs_test_extent_io();
2275 if (ret)
2276 goto out;
2277 ret = btrfs_test_inodes();
2278 if (ret)
2279 goto out;
2280 ret = btrfs_test_qgroups();
2281 out:
2282 btrfs_destroy_test_fs();
2283 return ret;
2284 }
2285
init_btrfs_fs(void)2286 static int __init init_btrfs_fs(void)
2287 {
2288 int err;
2289
2290 err = btrfs_hash_init();
2291 if (err)
2292 return err;
2293
2294 btrfs_props_init();
2295
2296 err = btrfs_init_sysfs();
2297 if (err)
2298 goto free_hash;
2299
2300 btrfs_init_compress();
2301
2302 err = btrfs_init_cachep();
2303 if (err)
2304 goto free_compress;
2305
2306 err = extent_io_init();
2307 if (err)
2308 goto free_cachep;
2309
2310 err = extent_map_init();
2311 if (err)
2312 goto free_extent_io;
2313
2314 err = ordered_data_init();
2315 if (err)
2316 goto free_extent_map;
2317
2318 err = btrfs_delayed_inode_init();
2319 if (err)
2320 goto free_ordered_data;
2321
2322 err = btrfs_auto_defrag_init();
2323 if (err)
2324 goto free_delayed_inode;
2325
2326 err = btrfs_delayed_ref_init();
2327 if (err)
2328 goto free_auto_defrag;
2329
2330 err = btrfs_prelim_ref_init();
2331 if (err)
2332 goto free_delayed_ref;
2333
2334 err = btrfs_end_io_wq_init();
2335 if (err)
2336 goto free_prelim_ref;
2337
2338 err = btrfs_interface_init();
2339 if (err)
2340 goto free_end_io_wq;
2341
2342 btrfs_init_lockdep();
2343
2344 btrfs_print_info();
2345
2346 err = btrfs_run_sanity_tests();
2347 if (err)
2348 goto unregister_ioctl;
2349
2350 err = register_filesystem(&btrfs_fs_type);
2351 if (err)
2352 goto unregister_ioctl;
2353
2354 return 0;
2355
2356 unregister_ioctl:
2357 btrfs_interface_exit();
2358 free_end_io_wq:
2359 btrfs_end_io_wq_exit();
2360 free_prelim_ref:
2361 btrfs_prelim_ref_exit();
2362 free_delayed_ref:
2363 btrfs_delayed_ref_exit();
2364 free_auto_defrag:
2365 btrfs_auto_defrag_exit();
2366 free_delayed_inode:
2367 btrfs_delayed_inode_exit();
2368 free_ordered_data:
2369 ordered_data_exit();
2370 free_extent_map:
2371 extent_map_exit();
2372 free_extent_io:
2373 extent_io_exit();
2374 free_cachep:
2375 btrfs_destroy_cachep();
2376 free_compress:
2377 btrfs_exit_compress();
2378 btrfs_exit_sysfs();
2379 free_hash:
2380 btrfs_hash_exit();
2381 return err;
2382 }
2383
exit_btrfs_fs(void)2384 static void __exit exit_btrfs_fs(void)
2385 {
2386 btrfs_destroy_cachep();
2387 btrfs_delayed_ref_exit();
2388 btrfs_auto_defrag_exit();
2389 btrfs_delayed_inode_exit();
2390 btrfs_prelim_ref_exit();
2391 ordered_data_exit();
2392 extent_map_exit();
2393 extent_io_exit();
2394 btrfs_interface_exit();
2395 btrfs_end_io_wq_exit();
2396 unregister_filesystem(&btrfs_fs_type);
2397 btrfs_exit_sysfs();
2398 btrfs_cleanup_fs_uuids();
2399 btrfs_exit_compress();
2400 btrfs_hash_exit();
2401 }
2402
2403 late_initcall(init_btrfs_fs);
2404 module_exit(exit_btrfs_fs)
2405
2406 MODULE_LICENSE("GPL");
2407