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Linux 3.12.28
[linux/fpc-iii.git] / fs / btrfs / super.c
blobe913328d0f2adc9c3beb2c37556a479c7615d2fa
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 "compat.h"
46 #include "delayed-inode.h"
47 #include "ctree.h"
48 #include "disk-io.h"
49 #include "transaction.h"
50 #include "btrfs_inode.h"
51 #include "print-tree.h"
52 #include "xattr.h"
53 #include "volumes.h"
54 #include "export.h"
55 #include "compression.h"
56 #include "rcu-string.h"
57 #include "dev-replace.h"
58 #include "free-space-cache.h"
59 #include "backref.h"
60 #include "tests/btrfs-tests.h"
61
62 #define CREATE_TRACE_POINTS
63 #include <trace/events/btrfs.h>
64
65 static const struct super_operations btrfs_super_ops;
66 static struct file_system_type btrfs_fs_type;
67
68 static const char *btrfs_decode_error(int errno)
69 {
70 char *errstr = "unknown";
71
72 switch (errno) {
73 case -EIO:
74 errstr = "IO failure";
75 break;
76 case -ENOMEM:
77 errstr = "Out of memory";
78 break;
79 case -EROFS:
80 errstr = "Readonly filesystem";
81 break;
82 case -EEXIST:
83 errstr = "Object already exists";
84 break;
85 case -ENOSPC:
86 errstr = "No space left";
87 break;
88 case -ENOENT:
89 errstr = "No such entry";
90 break;
91 }
92
93 return errstr;
94 }
95
96 static void save_error_info(struct btrfs_fs_info *fs_info)
97 {
98 /*
99 * today we only save the error info into ram. Long term we'll
100 * also send it down to the disk
101 */
102 set_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state);
103 }
104
105 /* btrfs handle error by forcing the filesystem readonly */
106 static void btrfs_handle_error(struct btrfs_fs_info *fs_info)
107 {
108 struct super_block *sb = fs_info->sb;
109
110 if (sb->s_flags & MS_RDONLY)
111 return;
112
113 if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
114 sb->s_flags |= MS_RDONLY;
115 btrfs_info(fs_info, "forced readonly");
116 /*
117 * Note that a running device replace operation is not
118 * canceled here although there is no way to update
119 * the progress. It would add the risk of a deadlock,
120 * therefore the canceling is ommited. The only penalty
121 * is that some I/O remains active until the procedure
122 * completes. The next time when the filesystem is
123 * mounted writeable again, the device replace
124 * operation continues.
125 */
126 }
127 }
128
129 #ifdef CONFIG_PRINTK
130 /*
131 * __btrfs_std_error decodes expected errors from the caller and
132 * invokes the approciate error response.
133 */
134 void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function,
135 unsigned int line, int errno, const char *fmt, ...)
136 {
137 struct super_block *sb = fs_info->sb;
138 const char *errstr;
139
140 /*
141 * Special case: if the error is EROFS, and we're already
142 * under MS_RDONLY, then it is safe here.
143 */
144 if (errno == -EROFS && (sb->s_flags & MS_RDONLY))
145 return;
146
147 errstr = btrfs_decode_error(errno);
148 if (fmt) {
149 struct va_format vaf;
150 va_list args;
151
152 va_start(args, fmt);
153 vaf.fmt = fmt;
154 vaf.va = &args;
155
156 printk(KERN_CRIT "BTRFS error (device %s) in %s:%d: errno=%d %s (%pV)\n",
157 sb->s_id, function, line, errno, errstr, &vaf);
158 va_end(args);
159 } else {
160 printk(KERN_CRIT "BTRFS error (device %s) in %s:%d: errno=%d %s\n",
161 sb->s_id, function, line, errno, errstr);
162 }
163
164 /* Don't go through full error handling during mount */
165 save_error_info(fs_info);
166 if (sb->s_flags & MS_BORN)
167 btrfs_handle_error(fs_info);
168 }
169
170 static const char * const logtypes[] = {
171 "emergency",
172 "alert",
173 "critical",
174 "error",
175 "warning",
176 "notice",
177 "info",
178 "debug",
179 };
180
181 void btrfs_printk(const struct btrfs_fs_info *fs_info, const char *fmt, ...)
182 {
183 struct super_block *sb = fs_info->sb;
184 char lvl[4];
185 struct va_format vaf;
186 va_list args;
187 const char *type = logtypes[4];
188 int kern_level;
189
190 va_start(args, fmt);
191
192 kern_level = printk_get_level(fmt);
193 if (kern_level) {
194 size_t size = printk_skip_level(fmt) - fmt;
195 memcpy(lvl, fmt, size);
196 lvl[size] = '\0';
197 fmt += size;
198 type = logtypes[kern_level - '0'];
199 } else
200 *lvl = '\0';
201
202 vaf.fmt = fmt;
203 vaf.va = &args;
204
205 printk("%sBTRFS %s (device %s): %pV\n", lvl, type, sb->s_id, &vaf);
206
207 va_end(args);
208 }
209
210 #else
211
212 void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function,
213 unsigned int line, int errno, const char *fmt, ...)
214 {
215 struct super_block *sb = fs_info->sb;
216
217 /*
218 * Special case: if the error is EROFS, and we're already
219 * under MS_RDONLY, then it is safe here.
220 */
221 if (errno == -EROFS && (sb->s_flags & MS_RDONLY))
222 return;
223
224 /* Don't go through full error handling during mount */
225 if (sb->s_flags & MS_BORN) {
226 save_error_info(fs_info);
227 btrfs_handle_error(fs_info);
228 }
229 }
230 #endif
231
232 /*
233 * We only mark the transaction aborted and then set the file system read-only.
234 * This will prevent new transactions from starting or trying to join this
235 * one.
236 *
237 * This means that error recovery at the call site is limited to freeing
238 * any local memory allocations and passing the error code up without
239 * further cleanup. The transaction should complete as it normally would
240 * in the call path but will return -EIO.
241 *
242 * We'll complete the cleanup in btrfs_end_transaction and
243 * btrfs_commit_transaction.
244 */
245 void __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
246 struct btrfs_root *root, const char *function,
247 unsigned int line, int errno)
248 {
249 /*
250 * Report first abort since mount
251 */
252 if (!test_and_set_bit(BTRFS_FS_STATE_TRANS_ABORTED,
253 &root->fs_info->fs_state)) {
254 WARN(1, KERN_DEBUG "btrfs: Transaction aborted (error %d)\n",
255 errno);
256 }
257 trans->aborted = errno;
258 /* Nothing used. The other threads that have joined this
259 * transaction may be able to continue. */
260 if (!trans->blocks_used) {
261 const char *errstr;
262
263 errstr = btrfs_decode_error(errno);
264 btrfs_warn(root->fs_info,
265 "%s:%d: Aborting unused transaction(%s).",
266 function, line, errstr);
267 return;
268 }
269 ACCESS_ONCE(trans->transaction->aborted) = errno;
270 /* Wake up anybody who may be waiting on this transaction */
271 wake_up(&root->fs_info->transaction_wait);
272 wake_up(&root->fs_info->transaction_blocked_wait);
273 __btrfs_std_error(root->fs_info, function, line, errno, NULL);
274 }
275 /*
276 * __btrfs_panic decodes unexpected, fatal errors from the caller,
277 * issues an alert, and either panics or BUGs, depending on mount options.
278 */
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 printk(KERN_CRIT "BTRFS panic (device %s) in %s:%d: %pV (errno=%d %s)\n",
299 s_id, 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 (void)close_ctree(btrfs_sb(sb)->tree_root);
307 /* FIXME: need to fix VFS to return error? */
308 /* AV: return it _where_? ->put_super() can be triggered by any number
309 * of async events, up to and including delivery of SIGKILL to the
310 * last process that kept it busy. Or segfault in the aforementioned
311 * process... Whom would you report that to?
312 */
313 }
314
315 enum {
316 Opt_degraded, Opt_subvol, Opt_subvolid, Opt_device, Opt_nodatasum,
317 Opt_nodatacow, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd,
318 Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl, Opt_compress,
319 Opt_compress_type, Opt_compress_force, Opt_compress_force_type,
320 Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard,
321 Opt_space_cache, Opt_clear_cache, Opt_user_subvol_rm_allowed,
322 Opt_enospc_debug, Opt_subvolrootid, Opt_defrag, Opt_inode_cache,
323 Opt_no_space_cache, Opt_recovery, Opt_skip_balance,
324 Opt_check_integrity, Opt_check_integrity_including_extent_data,
325 Opt_check_integrity_print_mask, Opt_fatal_errors, Opt_rescan_uuid_tree,
326 Opt_commit_interval,
327 Opt_err,
328 };
329
330 static match_table_t tokens = {
331 {Opt_degraded, "degraded"},
332 {Opt_subvol, "subvol=%s"},
333 {Opt_subvolid, "subvolid=%s"},
334 {Opt_device, "device=%s"},
335 {Opt_nodatasum, "nodatasum"},
336 {Opt_nodatacow, "nodatacow"},
337 {Opt_nobarrier, "nobarrier"},
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_noacl, "noacl"},
349 {Opt_notreelog, "notreelog"},
350 {Opt_flushoncommit, "flushoncommit"},
351 {Opt_ratio, "metadata_ratio=%d"},
352 {Opt_discard, "discard"},
353 {Opt_space_cache, "space_cache"},
354 {Opt_clear_cache, "clear_cache"},
355 {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
356 {Opt_enospc_debug, "enospc_debug"},
357 {Opt_subvolrootid, "subvolrootid=%d"},
358 {Opt_defrag, "autodefrag"},
359 {Opt_inode_cache, "inode_cache"},
360 {Opt_no_space_cache, "nospace_cache"},
361 {Opt_recovery, "recovery"},
362 {Opt_skip_balance, "skip_balance"},
363 {Opt_check_integrity, "check_int"},
364 {Opt_check_integrity_including_extent_data, "check_int_data"},
365 {Opt_check_integrity_print_mask, "check_int_print_mask=%d"},
366 {Opt_rescan_uuid_tree, "rescan_uuid_tree"},
367 {Opt_fatal_errors, "fatal_errors=%s"},
368 {Opt_commit_interval, "commit=%d"},
369 {Opt_err, NULL},
370 };
371
372 /*
373 * Regular mount options parser. Everything that is needed only when
374 * reading in a new superblock is parsed here.
375 * XXX JDM: This needs to be cleaned up for remount.
376 */
377 int btrfs_parse_options(struct btrfs_root *root, char *options)
378 {
379 struct btrfs_fs_info *info = root->fs_info;
380 substring_t args[MAX_OPT_ARGS];
381 char *p, *num, *orig = NULL;
382 u64 cache_gen;
383 int intarg;
384 int ret = 0;
385 char *compress_type;
386 bool compress_force = false;
387
388 cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
389 if (cache_gen)
390 btrfs_set_opt(info->mount_opt, SPACE_CACHE);
391
392 if (!options)
393 goto out;
394
395 /*
396 * strsep changes the string, duplicate it because parse_options
397 * gets called twice
398 */
399 options = kstrdup(options, GFP_NOFS);
400 if (!options)
401 return -ENOMEM;
402
403 orig = options;
404
405 while ((p = strsep(&options, ",")) != NULL) {
406 int token;
407 if (!*p)
408 continue;
409
410 token = match_token(p, tokens, args);
411 switch (token) {
412 case Opt_degraded:
413 printk(KERN_INFO "btrfs: allowing degraded mounts\n");
414 btrfs_set_opt(info->mount_opt, DEGRADED);
415 break;
416 case Opt_subvol:
417 case Opt_subvolid:
418 case Opt_subvolrootid:
419 case Opt_device:
420 /*
421 * These are parsed by btrfs_parse_early_options
422 * and can be happily ignored here.
423 */
424 break;
425 case Opt_nodatasum:
426 printk(KERN_INFO "btrfs: setting nodatasum\n");
427 btrfs_set_opt(info->mount_opt, NODATASUM);
428 break;
429 case Opt_nodatacow:
430 if (!btrfs_test_opt(root, COMPRESS) ||
431 !btrfs_test_opt(root, FORCE_COMPRESS)) {
432 printk(KERN_INFO "btrfs: setting nodatacow, compression disabled\n");
433 } else {
434 printk(KERN_INFO "btrfs: setting nodatacow\n");
435 }
436 info->compress_type = BTRFS_COMPRESS_NONE;
437 btrfs_clear_opt(info->mount_opt, COMPRESS);
438 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
439 btrfs_set_opt(info->mount_opt, NODATACOW);
440 btrfs_set_opt(info->mount_opt, NODATASUM);
441 break;
442 case Opt_compress_force:
443 case Opt_compress_force_type:
444 compress_force = true;
445 /* Fallthrough */
446 case Opt_compress:
447 case Opt_compress_type:
448 if (token == Opt_compress ||
449 token == Opt_compress_force ||
450 strcmp(args[0].from, "zlib") == 0) {
451 compress_type = "zlib";
452 info->compress_type = BTRFS_COMPRESS_ZLIB;
453 btrfs_set_opt(info->mount_opt, COMPRESS);
454 btrfs_clear_opt(info->mount_opt, NODATACOW);
455 btrfs_clear_opt(info->mount_opt, NODATASUM);
456 } else if (strcmp(args[0].from, "lzo") == 0) {
457 compress_type = "lzo";
458 info->compress_type = BTRFS_COMPRESS_LZO;
459 btrfs_set_opt(info->mount_opt, COMPRESS);
460 btrfs_clear_opt(info->mount_opt, NODATACOW);
461 btrfs_clear_opt(info->mount_opt, NODATASUM);
462 btrfs_set_fs_incompat(info, COMPRESS_LZO);
463 } else if (strncmp(args[0].from, "no", 2) == 0) {
464 compress_type = "no";
465 info->compress_type = BTRFS_COMPRESS_NONE;
466 btrfs_clear_opt(info->mount_opt, COMPRESS);
467 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
468 compress_force = false;
469 } else {
470 ret = -EINVAL;
471 goto out;
472 }
473
474 if (compress_force) {
475 btrfs_set_opt(info->mount_opt, FORCE_COMPRESS);
476 pr_info("btrfs: force %s compression\n",
477 compress_type);
478 } else
479 pr_info("btrfs: use %s compression\n",
480 compress_type);
481 break;
482 case Opt_ssd:
483 printk(KERN_INFO "btrfs: use ssd allocation scheme\n");
484 btrfs_set_opt(info->mount_opt, SSD);
485 break;
486 case Opt_ssd_spread:
487 printk(KERN_INFO "btrfs: use spread ssd "
488 "allocation scheme\n");
489 btrfs_set_opt(info->mount_opt, SSD);
490 btrfs_set_opt(info->mount_opt, SSD_SPREAD);
491 break;
492 case Opt_nossd:
493 printk(KERN_INFO "btrfs: not using ssd allocation "
494 "scheme\n");
495 btrfs_set_opt(info->mount_opt, NOSSD);
496 btrfs_clear_opt(info->mount_opt, SSD);
497 btrfs_clear_opt(info->mount_opt, SSD_SPREAD);
498 break;
499 case Opt_nobarrier:
500 printk(KERN_INFO "btrfs: turning off barriers\n");
501 btrfs_set_opt(info->mount_opt, NOBARRIER);
502 break;
503 case Opt_thread_pool:
504 ret = match_int(&args[0], &intarg);
505 if (ret) {
506 goto out;
507 } else if (intarg > 0) {
508 info->thread_pool_size = intarg;
509 } else {
510 ret = -EINVAL;
511 goto out;
512 }
513 break;
514 case Opt_max_inline:
515 num = match_strdup(&args[0]);
516 if (num) {
517 info->max_inline = memparse(num, NULL);
518 kfree(num);
519
520 if (info->max_inline) {
521 info->max_inline = max_t(u64,
522 info->max_inline,
523 root->sectorsize);
524 }
525 printk(KERN_INFO "btrfs: max_inline at %llu\n",
526 info->max_inline);
527 } else {
528 ret = -ENOMEM;
529 goto out;
530 }
531 break;
532 case Opt_alloc_start:
533 num = match_strdup(&args[0]);
534 if (num) {
535 mutex_lock(&info->chunk_mutex);
536 info->alloc_start = memparse(num, NULL);
537 mutex_unlock(&info->chunk_mutex);
538 kfree(num);
539 printk(KERN_INFO
540 "btrfs: allocations start at %llu\n",
541 info->alloc_start);
542 } else {
543 ret = -ENOMEM;
544 goto out;
545 }
546 break;
547 case Opt_noacl:
548 root->fs_info->sb->s_flags &= ~MS_POSIXACL;
549 break;
550 case Opt_notreelog:
551 printk(KERN_INFO "btrfs: disabling tree log\n");
552 btrfs_set_opt(info->mount_opt, NOTREELOG);
553 break;
554 case Opt_flushoncommit:
555 printk(KERN_INFO "btrfs: turning on flush-on-commit\n");
556 btrfs_set_opt(info->mount_opt, FLUSHONCOMMIT);
557 break;
558 case Opt_ratio:
559 ret = match_int(&args[0], &intarg);
560 if (ret) {
561 goto out;
562 } else if (intarg >= 0) {
563 info->metadata_ratio = intarg;
564 printk(KERN_INFO "btrfs: metadata ratio %d\n",
565 info->metadata_ratio);
566 } else {
567 ret = -EINVAL;
568 goto out;
569 }
570 break;
571 case Opt_discard:
572 btrfs_set_opt(info->mount_opt, DISCARD);
573 break;
574 case Opt_space_cache:
575 btrfs_set_opt(info->mount_opt, SPACE_CACHE);
576 break;
577 case Opt_rescan_uuid_tree:
578 btrfs_set_opt(info->mount_opt, RESCAN_UUID_TREE);
579 break;
580 case Opt_no_space_cache:
581 printk(KERN_INFO "btrfs: disabling disk space caching\n");
582 btrfs_clear_opt(info->mount_opt, SPACE_CACHE);
583 break;
584 case Opt_inode_cache:
585 printk(KERN_INFO "btrfs: enabling inode map caching\n");
586 btrfs_set_opt(info->mount_opt, INODE_MAP_CACHE);
587 break;
588 case Opt_clear_cache:
589 printk(KERN_INFO "btrfs: force clearing of disk cache\n");
590 btrfs_set_opt(info->mount_opt, CLEAR_CACHE);
591 break;
592 case Opt_user_subvol_rm_allowed:
593 btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
594 break;
595 case Opt_enospc_debug:
596 btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
597 break;
598 case Opt_defrag:
599 printk(KERN_INFO "btrfs: enabling auto defrag\n");
600 btrfs_set_opt(info->mount_opt, AUTO_DEFRAG);
601 break;
602 case Opt_recovery:
603 printk(KERN_INFO "btrfs: enabling auto recovery\n");
604 btrfs_set_opt(info->mount_opt, RECOVERY);
605 break;
606 case Opt_skip_balance:
607 btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
608 break;
609 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
610 case Opt_check_integrity_including_extent_data:
611 printk(KERN_INFO "btrfs: enabling check integrity"
612 " including extent data\n");
613 btrfs_set_opt(info->mount_opt,
614 CHECK_INTEGRITY_INCLUDING_EXTENT_DATA);
615 btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
616 break;
617 case Opt_check_integrity:
618 printk(KERN_INFO "btrfs: enabling check integrity\n");
619 btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
620 break;
621 case Opt_check_integrity_print_mask:
622 ret = match_int(&args[0], &intarg);
623 if (ret) {
624 goto out;
625 } else if (intarg >= 0) {
626 info->check_integrity_print_mask = intarg;
627 printk(KERN_INFO "btrfs:"
628 " check_integrity_print_mask 0x%x\n",
629 info->check_integrity_print_mask);
630 } else {
631 ret = -EINVAL;
632 goto out;
633 }
634 break;
635 #else
636 case Opt_check_integrity_including_extent_data:
637 case Opt_check_integrity:
638 case Opt_check_integrity_print_mask:
639 printk(KERN_ERR "btrfs: support for check_integrity*"
640 " not compiled in!\n");
641 ret = -EINVAL;
642 goto out;
643 #endif
644 case Opt_fatal_errors:
645 if (strcmp(args[0].from, "panic") == 0)
646 btrfs_set_opt(info->mount_opt,
647 PANIC_ON_FATAL_ERROR);
648 else if (strcmp(args[0].from, "bug") == 0)
649 btrfs_clear_opt(info->mount_opt,
650 PANIC_ON_FATAL_ERROR);
651 else {
652 ret = -EINVAL;
653 goto out;
654 }
655 break;
656 case Opt_commit_interval:
657 intarg = 0;
658 ret = match_int(&args[0], &intarg);
659 if (ret < 0) {
660 printk(KERN_ERR
661 "btrfs: invalid commit interval\n");
662 ret = -EINVAL;
663 goto out;
664 }
665 if (intarg > 0) {
666 if (intarg > 300) {
667 printk(KERN_WARNING
668 "btrfs: excessive commit interval %d\n",
669 intarg);
670 }
671 info->commit_interval = intarg;
672 } else {
673 printk(KERN_INFO
674 "btrfs: using default commit interval %ds\n",
675 BTRFS_DEFAULT_COMMIT_INTERVAL);
676 info->commit_interval = BTRFS_DEFAULT_COMMIT_INTERVAL;
677 }
678 break;
679 case Opt_err:
680 printk(KERN_INFO "btrfs: unrecognized mount option "
681 "'%s'\n", p);
682 ret = -EINVAL;
683 goto out;
684 default:
685 break;
686 }
687 }
688 out:
689 if (!ret && btrfs_test_opt(root, SPACE_CACHE))
690 printk(KERN_INFO "btrfs: disk space caching is enabled\n");
691 kfree(orig);
692 return ret;
693 }
694
695 /*
696 * Parse mount options that are required early in the mount process.
697 *
698 * All other options will be parsed on much later in the mount process and
699 * only when we need to allocate a new super block.
700 */
701 static int btrfs_parse_early_options(const char *options, fmode_t flags,
702 void *holder, char **subvol_name, u64 *subvol_objectid,
703 struct btrfs_fs_devices **fs_devices)
704 {
705 substring_t args[MAX_OPT_ARGS];
706 char *device_name, *opts, *orig, *p;
707 char *num = NULL;
708 int error = 0;
709
710 if (!options)
711 return 0;
712
713 /*
714 * strsep changes the string, duplicate it because parse_options
715 * gets called twice
716 */
717 opts = kstrdup(options, GFP_KERNEL);
718 if (!opts)
719 return -ENOMEM;
720 orig = opts;
721
722 while ((p = strsep(&opts, ",")) != NULL) {
723 int token;
724 if (!*p)
725 continue;
726
727 token = match_token(p, tokens, args);
728 switch (token) {
729 case Opt_subvol:
730 kfree(*subvol_name);
731 *subvol_name = match_strdup(&args[0]);
732 if (!*subvol_name) {
733 error = -ENOMEM;
734 goto out;
735 }
736 break;
737 case Opt_subvolid:
738 num = match_strdup(&args[0]);
739 if (num) {
740 *subvol_objectid = memparse(num, NULL);
741 kfree(num);
742 /* we want the original fs_tree */
743 if (!*subvol_objectid)
744 *subvol_objectid =
745 BTRFS_FS_TREE_OBJECTID;
746 } else {
747 error = -EINVAL;
748 goto out;
749 }
750 break;
751 case Opt_subvolrootid:
752 printk(KERN_WARNING
753 "btrfs: 'subvolrootid' mount option is deprecated and has no effect\n");
754 break;
755 case Opt_device:
756 device_name = match_strdup(&args[0]);
757 if (!device_name) {
758 error = -ENOMEM;
759 goto out;
760 }
761 error = btrfs_scan_one_device(device_name,
762 flags, holder, fs_devices);
763 kfree(device_name);
764 if (error)
765 goto out;
766 break;
767 default:
768 break;
769 }
770 }
771
772 out:
773 kfree(orig);
774 return error;
775 }
776
777 static struct dentry *get_default_root(struct super_block *sb,
778 u64 subvol_objectid)
779 {
780 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
781 struct btrfs_root *root = fs_info->tree_root;
782 struct btrfs_root *new_root;
783 struct btrfs_dir_item *di;
784 struct btrfs_path *path;
785 struct btrfs_key location;
786 struct inode *inode;
787 u64 dir_id;
788 int new = 0;
789
790 /*
791 * We have a specific subvol we want to mount, just setup location and
792 * go look up the root.
793 */
794 if (subvol_objectid) {
795 location.objectid = subvol_objectid;
796 location.type = BTRFS_ROOT_ITEM_KEY;
797 location.offset = (u64)-1;
798 goto find_root;
799 }
800
801 path = btrfs_alloc_path();
802 if (!path)
803 return ERR_PTR(-ENOMEM);
804 path->leave_spinning = 1;
805
806 /*
807 * Find the "default" dir item which points to the root item that we
808 * will mount by default if we haven't been given a specific subvolume
809 * to mount.
810 */
811 dir_id = btrfs_super_root_dir(fs_info->super_copy);
812 di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
813 if (IS_ERR(di)) {
814 btrfs_free_path(path);
815 return ERR_CAST(di);
816 }
817 if (!di) {
818 /*
819 * Ok the default dir item isn't there. This is weird since
820 * it's always been there, but don't freak out, just try and
821 * mount to root most subvolume.
822 */
823 btrfs_free_path(path);
824 dir_id = BTRFS_FIRST_FREE_OBJECTID;
825 new_root = fs_info->fs_root;
826 goto setup_root;
827 }
828
829 btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
830 btrfs_free_path(path);
831
832 find_root:
833 new_root = btrfs_read_fs_root_no_name(fs_info, &location);
834 if (IS_ERR(new_root))
835 return ERR_CAST(new_root);
836
837 dir_id = btrfs_root_dirid(&new_root->root_item);
838 setup_root:
839 location.objectid = dir_id;
840 location.type = BTRFS_INODE_ITEM_KEY;
841 location.offset = 0;
842
843 inode = btrfs_iget(sb, &location, new_root, &new);
844 if (IS_ERR(inode))
845 return ERR_CAST(inode);
846
847 /*
848 * If we're just mounting the root most subvol put the inode and return
849 * a reference to the dentry. We will have already gotten a reference
850 * to the inode in btrfs_fill_super so we're good to go.
851 */
852 if (!new && sb->s_root->d_inode == inode) {
853 iput(inode);
854 return dget(sb->s_root);
855 }
856
857 return d_obtain_alias(inode);
858 }
859
860 static int btrfs_fill_super(struct super_block *sb,
861 struct btrfs_fs_devices *fs_devices,
862 void *data, int silent)
863 {
864 struct inode *inode;
865 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
866 struct btrfs_key key;
867 int err;
868
869 sb->s_maxbytes = MAX_LFS_FILESIZE;
870 sb->s_magic = BTRFS_SUPER_MAGIC;
871 sb->s_op = &btrfs_super_ops;
872 sb->s_d_op = &btrfs_dentry_operations;
873 sb->s_export_op = &btrfs_export_ops;
874 sb->s_xattr = btrfs_xattr_handlers;
875 sb->s_time_gran = 1;
876 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
877 sb->s_flags |= MS_POSIXACL;
878 #endif
879 sb->s_flags |= MS_I_VERSION;
880 err = open_ctree(sb, fs_devices, (char *)data);
881 if (err) {
882 printk("btrfs: open_ctree failed\n");
883 return err;
884 }
885
886 key.objectid = BTRFS_FIRST_FREE_OBJECTID;
887 key.type = BTRFS_INODE_ITEM_KEY;
888 key.offset = 0;
889 inode = btrfs_iget(sb, &key, fs_info->fs_root, NULL);
890 if (IS_ERR(inode)) {
891 err = PTR_ERR(inode);
892 goto fail_close;
893 }
894
895 sb->s_root = d_make_root(inode);
896 if (!sb->s_root) {
897 err = -ENOMEM;
898 goto fail_close;
899 }
900
901 save_mount_options(sb, data);
902 cleancache_init_fs(sb);
903 sb->s_flags |= MS_ACTIVE;
904 return 0;
905
906 fail_close:
907 close_ctree(fs_info->tree_root);
908 return err;
909 }
910
911 int btrfs_sync_fs(struct super_block *sb, int wait)
912 {
913 struct btrfs_trans_handle *trans;
914 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
915 struct btrfs_root *root = fs_info->tree_root;
916
917 trace_btrfs_sync_fs(wait);
918
919 if (!wait) {
920 filemap_flush(fs_info->btree_inode->i_mapping);
921 return 0;
922 }
923
924 btrfs_wait_all_ordered_extents(fs_info);
925
926 trans = btrfs_attach_transaction_barrier(root);
927 if (IS_ERR(trans)) {
928 /* no transaction, don't bother */
929 if (PTR_ERR(trans) == -ENOENT)
930 return 0;
931 return PTR_ERR(trans);
932 }
933 return btrfs_commit_transaction(trans, root);
934 }
935
936 static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
937 {
938 struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
939 struct btrfs_root *root = info->tree_root;
940 char *compress_type;
941
942 if (btrfs_test_opt(root, DEGRADED))
943 seq_puts(seq, ",degraded");
944 if (btrfs_test_opt(root, NODATASUM))
945 seq_puts(seq, ",nodatasum");
946 if (btrfs_test_opt(root, NODATACOW))
947 seq_puts(seq, ",nodatacow");
948 if (btrfs_test_opt(root, NOBARRIER))
949 seq_puts(seq, ",nobarrier");
950 if (info->max_inline != 8192 * 1024)
951 seq_printf(seq, ",max_inline=%llu", info->max_inline);
952 if (info->alloc_start != 0)
953 seq_printf(seq, ",alloc_start=%llu", info->alloc_start);
954 if (info->thread_pool_size != min_t(unsigned long,
955 num_online_cpus() + 2, 8))
956 seq_printf(seq, ",thread_pool=%d", info->thread_pool_size);
957 if (btrfs_test_opt(root, COMPRESS)) {
958 if (info->compress_type == BTRFS_COMPRESS_ZLIB)
959 compress_type = "zlib";
960 else
961 compress_type = "lzo";
962 if (btrfs_test_opt(root, FORCE_COMPRESS))
963 seq_printf(seq, ",compress-force=%s", compress_type);
964 else
965 seq_printf(seq, ",compress=%s", compress_type);
966 }
967 if (btrfs_test_opt(root, NOSSD))
968 seq_puts(seq, ",nossd");
969 if (btrfs_test_opt(root, SSD_SPREAD))
970 seq_puts(seq, ",ssd_spread");
971 else if (btrfs_test_opt(root, SSD))
972 seq_puts(seq, ",ssd");
973 if (btrfs_test_opt(root, NOTREELOG))
974 seq_puts(seq, ",notreelog");
975 if (btrfs_test_opt(root, FLUSHONCOMMIT))
976 seq_puts(seq, ",flushoncommit");
977 if (btrfs_test_opt(root, DISCARD))
978 seq_puts(seq, ",discard");
979 if (!(root->fs_info->sb->s_flags & MS_POSIXACL))
980 seq_puts(seq, ",noacl");
981 if (btrfs_test_opt(root, SPACE_CACHE))
982 seq_puts(seq, ",space_cache");
983 else
984 seq_puts(seq, ",nospace_cache");
985 if (btrfs_test_opt(root, RESCAN_UUID_TREE))
986 seq_puts(seq, ",rescan_uuid_tree");
987 if (btrfs_test_opt(root, CLEAR_CACHE))
988 seq_puts(seq, ",clear_cache");
989 if (btrfs_test_opt(root, USER_SUBVOL_RM_ALLOWED))
990 seq_puts(seq, ",user_subvol_rm_allowed");
991 if (btrfs_test_opt(root, ENOSPC_DEBUG))
992 seq_puts(seq, ",enospc_debug");
993 if (btrfs_test_opt(root, AUTO_DEFRAG))
994 seq_puts(seq, ",autodefrag");
995 if (btrfs_test_opt(root, INODE_MAP_CACHE))
996 seq_puts(seq, ",inode_cache");
997 if (btrfs_test_opt(root, SKIP_BALANCE))
998 seq_puts(seq, ",skip_balance");
999 if (btrfs_test_opt(root, RECOVERY))
1000 seq_puts(seq, ",recovery");
1001 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
1002 if (btrfs_test_opt(root, CHECK_INTEGRITY_INCLUDING_EXTENT_DATA))
1003 seq_puts(seq, ",check_int_data");
1004 else if (btrfs_test_opt(root, CHECK_INTEGRITY))
1005 seq_puts(seq, ",check_int");
1006 if (info->check_integrity_print_mask)
1007 seq_printf(seq, ",check_int_print_mask=%d",
1008 info->check_integrity_print_mask);
1009 #endif
1010 if (info->metadata_ratio)
1011 seq_printf(seq, ",metadata_ratio=%d",
1012 info->metadata_ratio);
1013 if (btrfs_test_opt(root, PANIC_ON_FATAL_ERROR))
1014 seq_puts(seq, ",fatal_errors=panic");
1015 if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL)
1016 seq_printf(seq, ",commit=%d", info->commit_interval);
1017 return 0;
1018 }
1019
1020 static int btrfs_test_super(struct super_block *s, void *data)
1021 {
1022 struct btrfs_fs_info *p = data;
1023 struct btrfs_fs_info *fs_info = btrfs_sb(s);
1024
1025 return fs_info->fs_devices == p->fs_devices;
1026 }
1027
1028 static int btrfs_set_super(struct super_block *s, void *data)
1029 {
1030 int err = set_anon_super(s, data);
1031 if (!err)
1032 s->s_fs_info = data;
1033 return err;
1034 }
1035
1036 /*
1037 * subvolumes are identified by ino 256
1038 */
1039 static inline int is_subvolume_inode(struct inode *inode)
1040 {
1041 if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
1042 return 1;
1043 return 0;
1044 }
1045
1046 /*
1047 * This will strip out the subvol=%s argument for an argument string and add
1048 * subvolid=0 to make sure we get the actual tree root for path walking to the
1049 * subvol we want.
1050 */
1051 static char *setup_root_args(char *args)
1052 {
1053 unsigned len = strlen(args) + 2 + 1;
1054 char *src, *dst, *buf;
1055
1056 /*
1057 * We need the same args as before, but with this substitution:
1058 * s!subvol=[^,]+!subvolid=0!
1059 *
1060 * Since the replacement string is up to 2 bytes longer than the
1061 * original, allocate strlen(args) + 2 + 1 bytes.
1062 */
1063
1064 src = strstr(args, "subvol=");
1065 /* This shouldn't happen, but just in case.. */
1066 if (!src)
1067 return NULL;
1068
1069 buf = dst = kmalloc(len, GFP_NOFS);
1070 if (!buf)
1071 return NULL;
1072
1073 /*
1074 * If the subvol= arg is not at the start of the string,
1075 * copy whatever precedes it into buf.
1076 */
1077 if (src != args) {
1078 *src++ = '\0';
1079 strcpy(buf, args);
1080 dst += strlen(args);
1081 }
1082
1083 strcpy(dst, "subvolid=0");
1084 dst += strlen("subvolid=0");
1085
1086 /*
1087 * If there is a "," after the original subvol=... string,
1088 * copy that suffix into our buffer. Otherwise, we're done.
1089 */
1090 src = strchr(src, ',');
1091 if (src)
1092 strcpy(dst, src);
1093
1094 return buf;
1095 }
1096
1097 static struct dentry *mount_subvol(const char *subvol_name, int flags,
1098 const char *device_name, char *data)
1099 {
1100 struct dentry *root;
1101 struct vfsmount *mnt;
1102 char *newargs;
1103
1104 newargs = setup_root_args(data);
1105 if (!newargs)
1106 return ERR_PTR(-ENOMEM);
1107 mnt = vfs_kern_mount(&btrfs_fs_type, flags, device_name,
1108 newargs);
1109 kfree(newargs);
1110 if (IS_ERR(mnt))
1111 return ERR_CAST(mnt);
1112
1113 root = mount_subtree(mnt, subvol_name);
1114
1115 if (!IS_ERR(root) && !is_subvolume_inode(root->d_inode)) {
1116 struct super_block *s = root->d_sb;
1117 dput(root);
1118 root = ERR_PTR(-EINVAL);
1119 deactivate_locked_super(s);
1120 printk(KERN_ERR "btrfs: '%s' is not a valid subvolume\n",
1121 subvol_name);
1122 }
1123
1124 return root;
1125 }
1126
1127 /*
1128 * Find a superblock for the given device / mount point.
1129 *
1130 * Note: This is based on get_sb_bdev from fs/super.c with a few additions
1131 * for multiple device setup. Make sure to keep it in sync.
1132 */
1133 static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
1134 const char *device_name, void *data)
1135 {
1136 struct block_device *bdev = NULL;
1137 struct super_block *s;
1138 struct dentry *root;
1139 struct btrfs_fs_devices *fs_devices = NULL;
1140 struct btrfs_fs_info *fs_info = NULL;
1141 fmode_t mode = FMODE_READ;
1142 char *subvol_name = NULL;
1143 u64 subvol_objectid = 0;
1144 int error = 0;
1145
1146 if (!(flags & MS_RDONLY))
1147 mode |= FMODE_WRITE;
1148
1149 error = btrfs_parse_early_options(data, mode, fs_type,
1150 &subvol_name, &subvol_objectid,
1151 &fs_devices);
1152 if (error) {
1153 kfree(subvol_name);
1154 return ERR_PTR(error);
1155 }
1156
1157 if (subvol_name) {
1158 root = mount_subvol(subvol_name, flags, device_name, data);
1159 kfree(subvol_name);
1160 return root;
1161 }
1162
1163 error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices);
1164 if (error)
1165 return ERR_PTR(error);
1166
1167 /*
1168 * Setup a dummy root and fs_info for test/set super. This is because
1169 * we don't actually fill this stuff out until open_ctree, but we need
1170 * it for searching for existing supers, so this lets us do that and
1171 * then open_ctree will properly initialize everything later.
1172 */
1173 fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_NOFS);
1174 if (!fs_info)
1175 return ERR_PTR(-ENOMEM);
1176
1177 fs_info->fs_devices = fs_devices;
1178
1179 fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
1180 fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
1181 if (!fs_info->super_copy || !fs_info->super_for_commit) {
1182 error = -ENOMEM;
1183 goto error_fs_info;
1184 }
1185
1186 error = btrfs_open_devices(fs_devices, mode, fs_type);
1187 if (error)
1188 goto error_fs_info;
1189
1190 if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
1191 error = -EACCES;
1192 goto error_close_devices;
1193 }
1194
1195 bdev = fs_devices->latest_bdev;
1196 s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | MS_NOSEC,
1197 fs_info);
1198 if (IS_ERR(s)) {
1199 error = PTR_ERR(s);
1200 goto error_close_devices;
1201 }
1202
1203 if (s->s_root) {
1204 btrfs_close_devices(fs_devices);
1205 free_fs_info(fs_info);
1206 if ((flags ^ s->s_flags) & MS_RDONLY)
1207 error = -EBUSY;
1208 } else {
1209 char b[BDEVNAME_SIZE];
1210
1211 strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
1212 btrfs_sb(s)->bdev_holder = fs_type;
1213 error = btrfs_fill_super(s, fs_devices, data,
1214 flags & MS_SILENT ? 1 : 0);
1215 }
1216
1217 root = !error ? get_default_root(s, subvol_objectid) : ERR_PTR(error);
1218 if (IS_ERR(root))
1219 deactivate_locked_super(s);
1220
1221 return root;
1222
1223 error_close_devices:
1224 btrfs_close_devices(fs_devices);
1225 error_fs_info:
1226 free_fs_info(fs_info);
1227 return ERR_PTR(error);
1228 }
1229
1230 static void btrfs_set_max_workers(struct btrfs_workers *workers, int new_limit)
1231 {
1232 spin_lock_irq(&workers->lock);
1233 workers->max_workers = new_limit;
1234 spin_unlock_irq(&workers->lock);
1235 }
1236
1237 static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
1238 int new_pool_size, int old_pool_size)
1239 {
1240 if (new_pool_size == old_pool_size)
1241 return;
1242
1243 fs_info->thread_pool_size = new_pool_size;
1244
1245 printk(KERN_INFO "btrfs: resize thread pool %d -> %d\n",
1246 old_pool_size, new_pool_size);
1247
1248 btrfs_set_max_workers(&fs_info->generic_worker, new_pool_size);
1249 btrfs_set_max_workers(&fs_info->workers, new_pool_size);
1250 btrfs_set_max_workers(&fs_info->delalloc_workers, new_pool_size);
1251 btrfs_set_max_workers(&fs_info->submit_workers, new_pool_size);
1252 btrfs_set_max_workers(&fs_info->caching_workers, new_pool_size);
1253 btrfs_set_max_workers(&fs_info->fixup_workers, new_pool_size);
1254 btrfs_set_max_workers(&fs_info->endio_workers, new_pool_size);
1255 btrfs_set_max_workers(&fs_info->endio_meta_workers, new_pool_size);
1256 btrfs_set_max_workers(&fs_info->endio_meta_write_workers, new_pool_size);
1257 btrfs_set_max_workers(&fs_info->endio_write_workers, new_pool_size);
1258 btrfs_set_max_workers(&fs_info->endio_freespace_worker, new_pool_size);
1259 btrfs_set_max_workers(&fs_info->delayed_workers, new_pool_size);
1260 btrfs_set_max_workers(&fs_info->readahead_workers, new_pool_size);
1261 btrfs_set_max_workers(&fs_info->scrub_wr_completion_workers,
1262 new_pool_size);
1263 }
1264
1265 static inline void btrfs_remount_prepare(struct btrfs_fs_info *fs_info)
1266 {
1267 set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1268 }
1269
1270 static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info,
1271 unsigned long old_opts, int flags)
1272 {
1273 if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1274 (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1275 (flags & MS_RDONLY))) {
1276 /* wait for any defraggers to finish */
1277 wait_event(fs_info->transaction_wait,
1278 (atomic_read(&fs_info->defrag_running) == 0));
1279 if (flags & MS_RDONLY)
1280 sync_filesystem(fs_info->sb);
1281 }
1282 }
1283
1284 static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
1285 unsigned long old_opts)
1286 {
1287 /*
1288 * We need cleanup all defragable inodes if the autodefragment is
1289 * close or the fs is R/O.
1290 */
1291 if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1292 (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1293 (fs_info->sb->s_flags & MS_RDONLY))) {
1294 btrfs_cleanup_defrag_inodes(fs_info);
1295 }
1296
1297 clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1298 }
1299
1300 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
1301 {
1302 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1303 struct btrfs_root *root = fs_info->tree_root;
1304 unsigned old_flags = sb->s_flags;
1305 unsigned long old_opts = fs_info->mount_opt;
1306 unsigned long old_compress_type = fs_info->compress_type;
1307 u64 old_max_inline = fs_info->max_inline;
1308 u64 old_alloc_start = fs_info->alloc_start;
1309 int old_thread_pool_size = fs_info->thread_pool_size;
1310 unsigned int old_metadata_ratio = fs_info->metadata_ratio;
1311 int ret;
1312
1313 btrfs_remount_prepare(fs_info);
1314
1315 ret = btrfs_parse_options(root, data);
1316 if (ret) {
1317 ret = -EINVAL;
1318 goto restore;
1319 }
1320
1321 btrfs_remount_begin(fs_info, old_opts, *flags);
1322 btrfs_resize_thread_pool(fs_info,
1323 fs_info->thread_pool_size, old_thread_pool_size);
1324
1325 if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1326 goto out;
1327
1328 if (*flags & MS_RDONLY) {
1329 /*
1330 * this also happens on 'umount -rf' or on shutdown, when
1331 * the filesystem is busy.
1332 */
1333 sb->s_flags |= MS_RDONLY;
1334
1335 btrfs_dev_replace_suspend_for_unmount(fs_info);
1336 btrfs_scrub_cancel(fs_info);
1337 btrfs_pause_balance(fs_info);
1338
1339 ret = btrfs_commit_super(root);
1340 if (ret)
1341 goto restore;
1342 } else {
1343 if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state)) {
1344 btrfs_err(fs_info,
1345 "Remounting read-write after error is not allowed\n");
1346 ret = -EINVAL;
1347 goto restore;
1348 }
1349 if (fs_info->fs_devices->rw_devices == 0) {
1350 ret = -EACCES;
1351 goto restore;
1352 }
1353
1354 if (fs_info->fs_devices->missing_devices >
1355 fs_info->num_tolerated_disk_barrier_failures &&
1356 !(*flags & MS_RDONLY)) {
1357 printk(KERN_WARNING
1358 "Btrfs: too many missing devices, writeable remount is not allowed\n");
1359 ret = -EACCES;
1360 goto restore;
1361 }
1362
1363 if (btrfs_super_log_root(fs_info->super_copy) != 0) {
1364 ret = -EINVAL;
1365 goto restore;
1366 }
1367
1368 ret = btrfs_cleanup_fs_roots(fs_info);
1369 if (ret)
1370 goto restore;
1371
1372 /* recover relocation */
1373 ret = btrfs_recover_relocation(root);
1374 if (ret)
1375 goto restore;
1376
1377 ret = btrfs_resume_balance_async(fs_info);
1378 if (ret)
1379 goto restore;
1380
1381 ret = btrfs_resume_dev_replace_async(fs_info);
1382 if (ret) {
1383 pr_warn("btrfs: failed to resume dev_replace\n");
1384 goto restore;
1385 }
1386
1387 if (!fs_info->uuid_root) {
1388 pr_info("btrfs: creating UUID tree\n");
1389 ret = btrfs_create_uuid_tree(fs_info);
1390 if (ret) {
1391 pr_warn("btrfs: failed to create the uuid tree"
1392 "%d\n", ret);
1393 goto restore;
1394 }
1395 }
1396 sb->s_flags &= ~MS_RDONLY;
1397 }
1398 out:
1399 btrfs_remount_cleanup(fs_info, old_opts);
1400 return 0;
1401
1402 restore:
1403 /* We've hit an error - don't reset MS_RDONLY */
1404 if (sb->s_flags & MS_RDONLY)
1405 old_flags |= MS_RDONLY;
1406 sb->s_flags = old_flags;
1407 fs_info->mount_opt = old_opts;
1408 fs_info->compress_type = old_compress_type;
1409 fs_info->max_inline = old_max_inline;
1410 mutex_lock(&fs_info->chunk_mutex);
1411 fs_info->alloc_start = old_alloc_start;
1412 mutex_unlock(&fs_info->chunk_mutex);
1413 btrfs_resize_thread_pool(fs_info,
1414 old_thread_pool_size, fs_info->thread_pool_size);
1415 fs_info->metadata_ratio = old_metadata_ratio;
1416 btrfs_remount_cleanup(fs_info, old_opts);
1417 return ret;
1418 }
1419
1420 /* Used to sort the devices by max_avail(descending sort) */
1421 static int btrfs_cmp_device_free_bytes(const void *dev_info1,
1422 const void *dev_info2)
1423 {
1424 if (((struct btrfs_device_info *)dev_info1)->max_avail >
1425 ((struct btrfs_device_info *)dev_info2)->max_avail)
1426 return -1;
1427 else if (((struct btrfs_device_info *)dev_info1)->max_avail <
1428 ((struct btrfs_device_info *)dev_info2)->max_avail)
1429 return 1;
1430 else
1431 return 0;
1432 }
1433
1434 /*
1435 * sort the devices by max_avail, in which max free extent size of each device
1436 * is stored.(Descending Sort)
1437 */
1438 static inline void btrfs_descending_sort_devices(
1439 struct btrfs_device_info *devices,
1440 size_t nr_devices)
1441 {
1442 sort(devices, nr_devices, sizeof(struct btrfs_device_info),
1443 btrfs_cmp_device_free_bytes, NULL);
1444 }
1445
1446 /*
1447 * The helper to calc the free space on the devices that can be used to store
1448 * file data.
1449 */
1450 static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes)
1451 {
1452 struct btrfs_fs_info *fs_info = root->fs_info;
1453 struct btrfs_device_info *devices_info;
1454 struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
1455 struct btrfs_device *device;
1456 u64 skip_space;
1457 u64 type;
1458 u64 avail_space;
1459 u64 used_space;
1460 u64 min_stripe_size;
1461 int min_stripes = 1, num_stripes = 1;
1462 int i = 0, nr_devices;
1463 int ret;
1464
1465 nr_devices = fs_info->fs_devices->open_devices;
1466 BUG_ON(!nr_devices);
1467
1468 devices_info = kmalloc(sizeof(*devices_info) * nr_devices,
1469 GFP_NOFS);
1470 if (!devices_info)
1471 return -ENOMEM;
1472
1473 /* calc min stripe number for data space alloction */
1474 type = btrfs_get_alloc_profile(root, 1);
1475 if (type & BTRFS_BLOCK_GROUP_RAID0) {
1476 min_stripes = 2;
1477 num_stripes = nr_devices;
1478 } else if (type & BTRFS_BLOCK_GROUP_RAID1) {
1479 min_stripes = 2;
1480 num_stripes = 2;
1481 } else if (type & BTRFS_BLOCK_GROUP_RAID10) {
1482 min_stripes = 4;
1483 num_stripes = 4;
1484 }
1485
1486 if (type & BTRFS_BLOCK_GROUP_DUP)
1487 min_stripe_size = 2 * BTRFS_STRIPE_LEN;
1488 else
1489 min_stripe_size = BTRFS_STRIPE_LEN;
1490
1491 list_for_each_entry(device, &fs_devices->devices, dev_list) {
1492 if (!device->in_fs_metadata || !device->bdev ||
1493 device->is_tgtdev_for_dev_replace)
1494 continue;
1495
1496 avail_space = device->total_bytes - device->bytes_used;
1497
1498 /* align with stripe_len */
1499 do_div(avail_space, BTRFS_STRIPE_LEN);
1500 avail_space *= BTRFS_STRIPE_LEN;
1501
1502 /*
1503 * In order to avoid overwritting the superblock on the drive,
1504 * btrfs starts at an offset of at least 1MB when doing chunk
1505 * allocation.
1506 */
1507 skip_space = 1024 * 1024;
1508
1509 /* user can set the offset in fs_info->alloc_start. */
1510 if (fs_info->alloc_start + BTRFS_STRIPE_LEN <=
1511 device->total_bytes)
1512 skip_space = max(fs_info->alloc_start, skip_space);
1513
1514 /*
1515 * btrfs can not use the free space in [0, skip_space - 1],
1516 * we must subtract it from the total. In order to implement
1517 * it, we account the used space in this range first.
1518 */
1519 ret = btrfs_account_dev_extents_size(device, 0, skip_space - 1,
1520 &used_space);
1521 if (ret) {
1522 kfree(devices_info);
1523 return ret;
1524 }
1525
1526 /* calc the free space in [0, skip_space - 1] */
1527 skip_space -= used_space;
1528
1529 /*
1530 * we can use the free space in [0, skip_space - 1], subtract
1531 * it from the total.
1532 */
1533 if (avail_space && avail_space >= skip_space)
1534 avail_space -= skip_space;
1535 else
1536 avail_space = 0;
1537
1538 if (avail_space < min_stripe_size)
1539 continue;
1540
1541 devices_info[i].dev = device;
1542 devices_info[i].max_avail = avail_space;
1543
1544 i++;
1545 }
1546
1547 nr_devices = i;
1548
1549 btrfs_descending_sort_devices(devices_info, nr_devices);
1550
1551 i = nr_devices - 1;
1552 avail_space = 0;
1553 while (nr_devices >= min_stripes) {
1554 if (num_stripes > nr_devices)
1555 num_stripes = nr_devices;
1556
1557 if (devices_info[i].max_avail >= min_stripe_size) {
1558 int j;
1559 u64 alloc_size;
1560
1561 avail_space += devices_info[i].max_avail * num_stripes;
1562 alloc_size = devices_info[i].max_avail;
1563 for (j = i + 1 - num_stripes; j <= i; j++)
1564 devices_info[j].max_avail -= alloc_size;
1565 }
1566 i--;
1567 nr_devices--;
1568 }
1569
1570 kfree(devices_info);
1571 *free_bytes = avail_space;
1572 return 0;
1573 }
1574
1575 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
1576 {
1577 struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
1578 struct btrfs_super_block *disk_super = fs_info->super_copy;
1579 struct list_head *head = &fs_info->space_info;
1580 struct btrfs_space_info *found;
1581 u64 total_used = 0;
1582 u64 total_free_data = 0;
1583 int bits = dentry->d_sb->s_blocksize_bits;
1584 __be32 *fsid = (__be32 *)fs_info->fsid;
1585 int ret;
1586
1587 /* holding chunk_muext to avoid allocating new chunks */
1588 mutex_lock(&fs_info->chunk_mutex);
1589 rcu_read_lock();
1590 list_for_each_entry_rcu(found, head, list) {
1591 if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
1592 total_free_data += found->disk_total - found->disk_used;
1593 total_free_data -=
1594 btrfs_account_ro_block_groups_free_space(found);
1595 }
1596
1597 total_used += found->disk_used;
1598 }
1599 rcu_read_unlock();
1600
1601 buf->f_namelen = BTRFS_NAME_LEN;
1602 buf->f_blocks = btrfs_super_total_bytes(disk_super) >> bits;
1603 buf->f_bfree = buf->f_blocks - (total_used >> bits);
1604 buf->f_bsize = dentry->d_sb->s_blocksize;
1605 buf->f_type = BTRFS_SUPER_MAGIC;
1606 buf->f_bavail = total_free_data;
1607 ret = btrfs_calc_avail_data_space(fs_info->tree_root, &total_free_data);
1608 if (ret) {
1609 mutex_unlock(&fs_info->chunk_mutex);
1610 return ret;
1611 }
1612 buf->f_bavail += total_free_data;
1613 buf->f_bavail = buf->f_bavail >> bits;
1614 mutex_unlock(&fs_info->chunk_mutex);
1615
1616 /* We treat it as constant endianness (it doesn't matter _which_)
1617 because we want the fsid to come out the same whether mounted
1618 on a big-endian or little-endian host */
1619 buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
1620 buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
1621 /* Mask in the root object ID too, to disambiguate subvols */
1622 buf->f_fsid.val[0] ^= BTRFS_I(dentry->d_inode)->root->objectid >> 32;
1623 buf->f_fsid.val[1] ^= BTRFS_I(dentry->d_inode)->root->objectid;
1624
1625 return 0;
1626 }
1627
1628 static void btrfs_kill_super(struct super_block *sb)
1629 {
1630 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1631 kill_anon_super(sb);
1632 free_fs_info(fs_info);
1633 }
1634
1635 static struct file_system_type btrfs_fs_type = {
1636 .owner = THIS_MODULE,
1637 .name = "btrfs",
1638 .mount = btrfs_mount,
1639 .kill_sb = btrfs_kill_super,
1640 .fs_flags = FS_REQUIRES_DEV,
1641 };
1642 MODULE_ALIAS_FS("btrfs");
1643
1644 /*
1645 * used by btrfsctl to scan devices when no FS is mounted
1646 */
1647 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
1648 unsigned long arg)
1649 {
1650 struct btrfs_ioctl_vol_args *vol;
1651 struct btrfs_fs_devices *fs_devices;
1652 int ret = -ENOTTY;
1653
1654 if (!capable(CAP_SYS_ADMIN))
1655 return -EPERM;
1656
1657 vol = memdup_user((void __user *)arg, sizeof(*vol));
1658 if (IS_ERR(vol))
1659 return PTR_ERR(vol);
1660
1661 switch (cmd) {
1662 case BTRFS_IOC_SCAN_DEV:
1663 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
1664 &btrfs_fs_type, &fs_devices);
1665 break;
1666 case BTRFS_IOC_DEVICES_READY:
1667 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
1668 &btrfs_fs_type, &fs_devices);
1669 if (ret)
1670 break;
1671 ret = !(fs_devices->num_devices == fs_devices->total_devices);
1672 break;
1673 }
1674
1675 kfree(vol);
1676 return ret;
1677 }
1678
1679 static int btrfs_freeze(struct super_block *sb)
1680 {
1681 struct btrfs_trans_handle *trans;
1682 struct btrfs_root *root = btrfs_sb(sb)->tree_root;
1683
1684 trans = btrfs_attach_transaction_barrier(root);
1685 if (IS_ERR(trans)) {
1686 /* no transaction, don't bother */
1687 if (PTR_ERR(trans) == -ENOENT)
1688 return 0;
1689 return PTR_ERR(trans);
1690 }
1691 return btrfs_commit_transaction(trans, root);
1692 }
1693
1694 static int btrfs_unfreeze(struct super_block *sb)
1695 {
1696 return 0;
1697 }
1698
1699 static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
1700 {
1701 struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
1702 struct btrfs_fs_devices *cur_devices;
1703 struct btrfs_device *dev, *first_dev = NULL;
1704 struct list_head *head;
1705 struct rcu_string *name;
1706
1707 mutex_lock(&fs_info->fs_devices->device_list_mutex);
1708 cur_devices = fs_info->fs_devices;
1709 while (cur_devices) {
1710 head = &cur_devices->devices;
1711 list_for_each_entry(dev, head, dev_list) {
1712 if (dev->missing)
1713 continue;
1714 if (!first_dev || dev->devid < first_dev->devid)
1715 first_dev = dev;
1716 }
1717 cur_devices = cur_devices->seed;
1718 }
1719
1720 if (first_dev) {
1721 rcu_read_lock();
1722 name = rcu_dereference(first_dev->name);
1723 seq_escape(m, name->str, " \t\n\\");
1724 rcu_read_unlock();
1725 } else {
1726 WARN_ON(1);
1727 }
1728 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
1729 return 0;
1730 }
1731
1732 static const struct super_operations btrfs_super_ops = {
1733 .drop_inode = btrfs_drop_inode,
1734 .evict_inode = btrfs_evict_inode,
1735 .put_super = btrfs_put_super,
1736 .sync_fs = btrfs_sync_fs,
1737 .show_options = btrfs_show_options,
1738 .show_devname = btrfs_show_devname,
1739 .write_inode = btrfs_write_inode,
1740 .alloc_inode = btrfs_alloc_inode,
1741 .destroy_inode = btrfs_destroy_inode,
1742 .statfs = btrfs_statfs,
1743 .remount_fs = btrfs_remount,
1744 .freeze_fs = btrfs_freeze,
1745 .unfreeze_fs = btrfs_unfreeze,
1746 };
1747
1748 static const struct file_operations btrfs_ctl_fops = {
1749 .unlocked_ioctl = btrfs_control_ioctl,
1750 .compat_ioctl = btrfs_control_ioctl,
1751 .owner = THIS_MODULE,
1752 .llseek = noop_llseek,
1753 };
1754
1755 static struct miscdevice btrfs_misc = {
1756 .minor = BTRFS_MINOR,
1757 .name = "btrfs-control",
1758 .fops = &btrfs_ctl_fops
1759 };
1760
1761 MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
1762 MODULE_ALIAS("devname:btrfs-control");
1763
1764 static int btrfs_interface_init(void)
1765 {
1766 return misc_register(&btrfs_misc);
1767 }
1768
1769 static void btrfs_interface_exit(void)
1770 {
1771 if (misc_deregister(&btrfs_misc) < 0)
1772 printk(KERN_INFO "btrfs: misc_deregister failed for control device\n");
1773 }
1774
1775 static void btrfs_print_info(void)
1776 {
1777 printk(KERN_INFO "Btrfs loaded"
1778 #ifdef CONFIG_BTRFS_DEBUG
1779 ", debug=on"
1780 #endif
1781 #ifdef CONFIG_BTRFS_ASSERT
1782 ", assert=on"
1783 #endif
1784 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
1785 ", integrity-checker=on"
1786 #endif
1787 "\n");
1788 }
1789
1790 static int btrfs_run_sanity_tests(void)
1791 {
1792 return btrfs_test_free_space_cache();
1793 }
1794
1795 static int __init init_btrfs_fs(void)
1796 {
1797 int err;
1798
1799 err = btrfs_init_sysfs();
1800 if (err)
1801 return err;
1802
1803 btrfs_init_compress();
1804
1805 err = btrfs_init_cachep();
1806 if (err)
1807 goto free_compress;
1808
1809 err = extent_io_init();
1810 if (err)
1811 goto free_cachep;
1812
1813 err = extent_map_init();
1814 if (err)
1815 goto free_extent_io;
1816
1817 err = ordered_data_init();
1818 if (err)
1819 goto free_extent_map;
1820
1821 err = btrfs_delayed_inode_init();
1822 if (err)
1823 goto free_ordered_data;
1824
1825 err = btrfs_auto_defrag_init();
1826 if (err)
1827 goto free_delayed_inode;
1828
1829 err = btrfs_delayed_ref_init();
1830 if (err)
1831 goto free_auto_defrag;
1832
1833 err = btrfs_prelim_ref_init();
1834 if (err)
1835 goto free_prelim_ref;
1836
1837 err = btrfs_interface_init();
1838 if (err)
1839 goto free_delayed_ref;
1840
1841 btrfs_init_lockdep();
1842
1843 btrfs_print_info();
1844
1845 err = btrfs_run_sanity_tests();
1846 if (err)
1847 goto unregister_ioctl;
1848
1849 err = register_filesystem(&btrfs_fs_type);
1850 if (err)
1851 goto unregister_ioctl;
1852
1853 return 0;
1854
1855 unregister_ioctl:
1856 btrfs_interface_exit();
1857 free_prelim_ref:
1858 btrfs_prelim_ref_exit();
1859 free_delayed_ref:
1860 btrfs_delayed_ref_exit();
1861 free_auto_defrag:
1862 btrfs_auto_defrag_exit();
1863 free_delayed_inode:
1864 btrfs_delayed_inode_exit();
1865 free_ordered_data:
1866 ordered_data_exit();
1867 free_extent_map:
1868 extent_map_exit();
1869 free_extent_io:
1870 extent_io_exit();
1871 free_cachep:
1872 btrfs_destroy_cachep();
1873 free_compress:
1874 btrfs_exit_compress();
1875 btrfs_exit_sysfs();
1876 return err;
1877 }
1878
1879 static void __exit exit_btrfs_fs(void)
1880 {
1881 btrfs_destroy_cachep();
1882 btrfs_delayed_ref_exit();
1883 btrfs_auto_defrag_exit();
1884 btrfs_delayed_inode_exit();
1885 btrfs_prelim_ref_exit();
1886 ordered_data_exit();
1887 extent_map_exit();
1888 extent_io_exit();
1889 btrfs_interface_exit();
1890 unregister_filesystem(&btrfs_fs_type);
1891 btrfs_exit_sysfs();
1892 btrfs_cleanup_fs_uuids();
1893 btrfs_exit_compress();
1894 }
1895
1896 module_init(init_btrfs_fs)
1897 module_exit(exit_btrfs_fs)
1898
1899 MODULE_LICENSE("GPL");
Linux with added FPC-III support