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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 "compat.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 "ioctl.h"
51 #include "print-tree.h"
52 #include "xattr.h"
53 #include "volumes.h"
54 #include "version.h"
55 #include "export.h"
56 #include "compression.h"
57 #include "rcu-string.h"
58 #include "dev-replace.h"
59
60 #define CREATE_TRACE_POINTS
61 #include <trace/events/btrfs.h>
62
63 static const struct super_operations btrfs_super_ops;
64 static struct file_system_type btrfs_fs_type;
65
66 static const char *btrfs_decode_error(struct btrfs_fs_info *fs_info, int errno,
67 char nbuf[16])
68 {
69 char *errstr = NULL;
70
71 switch (errno) {
72 case -EIO:
73 errstr = "IO failure";
74 break;
75 case -ENOMEM:
76 errstr = "Out of memory";
77 break;
78 case -EROFS:
79 errstr = "Readonly filesystem";
80 break;
81 case -EEXIST:
82 errstr = "Object already exists";
83 break;
84 default:
85 if (nbuf) {
86 if (snprintf(nbuf, 16, "error %d", -errno) >= 0)
87 errstr = nbuf;
88 }
89 break;
90 }
91
92 return errstr;
93 }
94
95 static void __save_error_info(struct btrfs_fs_info *fs_info)
96 {
97 /*
98 * today we only save the error info into ram. Long term we'll
99 * also send it down to the disk
100 */
101 fs_info->fs_state = BTRFS_SUPER_FLAG_ERROR;
102 }
103
104 static void save_error_info(struct btrfs_fs_info *fs_info)
105 {
106 __save_error_info(fs_info);
107 }
108
109 /* btrfs handle error by forcing the filesystem readonly */
110 static void btrfs_handle_error(struct btrfs_fs_info *fs_info)
111 {
112 struct super_block *sb = fs_info->sb;
113
114 if (sb->s_flags & MS_RDONLY)
115 return;
116
117 if (fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
118 sb->s_flags |= MS_RDONLY;
119 printk(KERN_INFO "btrfs is forced readonly\n");
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 // WARN_ON(1);
131 }
132 }
133
134 #ifdef CONFIG_PRINTK
135 /*
136 * __btrfs_std_error decodes expected errors from the caller and
137 * invokes the approciate error response.
138 */
139 void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function,
140 unsigned int line, int errno, const char *fmt, ...)
141 {
142 struct super_block *sb = fs_info->sb;
143 char nbuf[16];
144 const char *errstr;
145 va_list args;
146 va_start(args, fmt);
147
148 /*
149 * Special case: if the error is EROFS, and we're already
150 * under MS_RDONLY, then it is safe here.
151 */
152 if (errno == -EROFS && (sb->s_flags & MS_RDONLY))
153 return;
154
155 errstr = btrfs_decode_error(fs_info, errno, nbuf);
156 if (fmt) {
157 struct va_format vaf = {
158 .fmt = fmt,
159 .va = &args,
160 };
161
162 printk(KERN_CRIT "BTRFS error (device %s) in %s:%d: %s (%pV)\n",
163 sb->s_id, function, line, errstr, &vaf);
164 } else {
165 printk(KERN_CRIT "BTRFS error (device %s) in %s:%d: %s\n",
166 sb->s_id, function, line, errstr);
167 }
168
169 /* Don't go through full error handling during mount */
170 if (sb->s_flags & MS_BORN) {
171 save_error_info(fs_info);
172 btrfs_handle_error(fs_info);
173 }
174 va_end(args);
175 }
176
177 static const char * const logtypes[] = {
178 "emergency",
179 "alert",
180 "critical",
181 "error",
182 "warning",
183 "notice",
184 "info",
185 "debug",
186 };
187
188 void btrfs_printk(struct btrfs_fs_info *fs_info, const char *fmt, ...)
189 {
190 struct super_block *sb = fs_info->sb;
191 char lvl[4];
192 struct va_format vaf;
193 va_list args;
194 const char *type = logtypes[4];
195 int kern_level;
196
197 va_start(args, fmt);
198
199 kern_level = printk_get_level(fmt);
200 if (kern_level) {
201 size_t size = printk_skip_level(fmt) - fmt;
202 memcpy(lvl, fmt, size);
203 lvl[size] = '\0';
204 fmt += size;
205 type = logtypes[kern_level - '0'];
206 } else
207 *lvl = '\0';
208
209 vaf.fmt = fmt;
210 vaf.va = &args;
211
212 printk("%sBTRFS %s (device %s): %pV", lvl, type, sb->s_id, &vaf);
213
214 va_end(args);
215 }
216
217 #else
218
219 void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function,
220 unsigned int line, int errno, const char *fmt, ...)
221 {
222 struct super_block *sb = fs_info->sb;
223
224 /*
225 * Special case: if the error is EROFS, and we're already
226 * under MS_RDONLY, then it is safe here.
227 */
228 if (errno == -EROFS && (sb->s_flags & MS_RDONLY))
229 return;
230
231 /* Don't go through full error handling during mount */
232 if (sb->s_flags & MS_BORN) {
233 save_error_info(fs_info);
234 btrfs_handle_error(fs_info);
235 }
236 }
237 #endif
238
239 /*
240 * We only mark the transaction aborted and then set the file system read-only.
241 * This will prevent new transactions from starting or trying to join this
242 * one.
243 *
244 * This means that error recovery at the call site is limited to freeing
245 * any local memory allocations and passing the error code up without
246 * further cleanup. The transaction should complete as it normally would
247 * in the call path but will return -EIO.
248 *
249 * We'll complete the cleanup in btrfs_end_transaction and
250 * btrfs_commit_transaction.
251 */
252 void __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
253 struct btrfs_root *root, const char *function,
254 unsigned int line, int errno)
255 {
256 WARN_ONCE(1, KERN_DEBUG "btrfs: Transaction aborted\n");
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 char nbuf[16];
262 const char *errstr;
263
264 errstr = btrfs_decode_error(root->fs_info, errno, nbuf);
265 btrfs_printk(root->fs_info,
266 "%s:%d: Aborting unused transaction(%s).\n",
267 function, line, errstr);
268 return;
269 }
270 trans->transaction->aborted = errno;
271 __btrfs_std_error(root->fs_info, function, line, errno, NULL);
272 }
273 /*
274 * __btrfs_panic decodes unexpected, fatal errors from the caller,
275 * issues an alert, and either panics or BUGs, depending on mount options.
276 */
277 void __btrfs_panic(struct btrfs_fs_info *fs_info, const char *function,
278 unsigned int line, int errno, const char *fmt, ...)
279 {
280 char nbuf[16];
281 char *s_id = "<unknown>";
282 const char *errstr;
283 struct va_format vaf = { .fmt = fmt };
284 va_list args;
285
286 if (fs_info)
287 s_id = fs_info->sb->s_id;
288
289 va_start(args, fmt);
290 vaf.va = &args;
291
292 errstr = btrfs_decode_error(fs_info, errno, nbuf);
293 if (fs_info->mount_opt & BTRFS_MOUNT_PANIC_ON_FATAL_ERROR)
294 panic(KERN_CRIT "BTRFS panic (device %s) in %s:%d: %pV (%s)\n",
295 s_id, function, line, &vaf, errstr);
296
297 printk(KERN_CRIT "BTRFS panic (device %s) in %s:%d: %pV (%s)\n",
298 s_id, function, line, &vaf, errstr);
299 va_end(args);
300 /* Caller calls BUG() */
301 }
302
303 static void btrfs_put_super(struct super_block *sb)
304 {
305 (void)close_ctree(btrfs_sb(sb)->tree_root);
306 /* FIXME: need to fix VFS to return error? */
307 /* AV: return it _where_? ->put_super() can be triggered by any number
308 * of async events, up to and including delivery of SIGKILL to the
309 * last process that kept it busy. Or segfault in the aforementioned
310 * process... Whom would you report that to?
311 */
312 }
313
314 enum {
315 Opt_degraded, Opt_subvol, Opt_subvolid, Opt_device, Opt_nodatasum,
316 Opt_nodatacow, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd,
317 Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl, Opt_compress,
318 Opt_compress_type, Opt_compress_force, Opt_compress_force_type,
319 Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard,
320 Opt_space_cache, Opt_clear_cache, Opt_user_subvol_rm_allowed,
321 Opt_enospc_debug, Opt_subvolrootid, Opt_defrag, Opt_inode_cache,
322 Opt_no_space_cache, Opt_recovery, Opt_skip_balance,
323 Opt_check_integrity, Opt_check_integrity_including_extent_data,
324 Opt_check_integrity_print_mask, Opt_fatal_errors,
325 Opt_err,
326 };
327
328 static match_table_t tokens = {
329 {Opt_degraded, "degraded"},
330 {Opt_subvol, "subvol=%s"},
331 {Opt_subvolid, "subvolid=%d"},
332 {Opt_device, "device=%s"},
333 {Opt_nodatasum, "nodatasum"},
334 {Opt_nodatacow, "nodatacow"},
335 {Opt_nobarrier, "nobarrier"},
336 {Opt_max_inline, "max_inline=%s"},
337 {Opt_alloc_start, "alloc_start=%s"},
338 {Opt_thread_pool, "thread_pool=%d"},
339 {Opt_compress, "compress"},
340 {Opt_compress_type, "compress=%s"},
341 {Opt_compress_force, "compress-force"},
342 {Opt_compress_force_type, "compress-force=%s"},
343 {Opt_ssd, "ssd"},
344 {Opt_ssd_spread, "ssd_spread"},
345 {Opt_nossd, "nossd"},
346 {Opt_noacl, "noacl"},
347 {Opt_notreelog, "notreelog"},
348 {Opt_flushoncommit, "flushoncommit"},
349 {Opt_ratio, "metadata_ratio=%d"},
350 {Opt_discard, "discard"},
351 {Opt_space_cache, "space_cache"},
352 {Opt_clear_cache, "clear_cache"},
353 {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
354 {Opt_enospc_debug, "enospc_debug"},
355 {Opt_subvolrootid, "subvolrootid=%d"},
356 {Opt_defrag, "autodefrag"},
357 {Opt_inode_cache, "inode_cache"},
358 {Opt_no_space_cache, "nospace_cache"},
359 {Opt_recovery, "recovery"},
360 {Opt_skip_balance, "skip_balance"},
361 {Opt_check_integrity, "check_int"},
362 {Opt_check_integrity_including_extent_data, "check_int_data"},
363 {Opt_check_integrity_print_mask, "check_int_print_mask=%d"},
364 {Opt_fatal_errors, "fatal_errors=%s"},
365 {Opt_err, NULL},
366 };
367
368 /*
369 * Regular mount options parser. Everything that is needed only when
370 * reading in a new superblock is parsed here.
371 * XXX JDM: This needs to be cleaned up for remount.
372 */
373 int btrfs_parse_options(struct btrfs_root *root, char *options)
374 {
375 struct btrfs_fs_info *info = root->fs_info;
376 substring_t args[MAX_OPT_ARGS];
377 char *p, *num, *orig = NULL;
378 u64 cache_gen;
379 int intarg;
380 int ret = 0;
381 char *compress_type;
382 bool compress_force = false;
383
384 cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
385 if (cache_gen)
386 btrfs_set_opt(info->mount_opt, SPACE_CACHE);
387
388 if (!options)
389 goto out;
390
391 /*
392 * strsep changes the string, duplicate it because parse_options
393 * gets called twice
394 */
395 options = kstrdup(options, GFP_NOFS);
396 if (!options)
397 return -ENOMEM;
398
399 orig = options;
400
401 while ((p = strsep(&options, ",")) != NULL) {
402 int token;
403 if (!*p)
404 continue;
405
406 token = match_token(p, tokens, args);
407 switch (token) {
408 case Opt_degraded:
409 printk(KERN_INFO "btrfs: allowing degraded mounts\n");
410 btrfs_set_opt(info->mount_opt, DEGRADED);
411 break;
412 case Opt_subvol:
413 case Opt_subvolid:
414 case Opt_subvolrootid:
415 case Opt_device:
416 /*
417 * These are parsed by btrfs_parse_early_options
418 * and can be happily ignored here.
419 */
420 break;
421 case Opt_nodatasum:
422 printk(KERN_INFO "btrfs: setting nodatasum\n");
423 btrfs_set_opt(info->mount_opt, NODATASUM);
424 break;
425 case Opt_nodatacow:
426 if (!btrfs_test_opt(root, COMPRESS) ||
427 !btrfs_test_opt(root, FORCE_COMPRESS)) {
428 printk(KERN_INFO "btrfs: setting nodatacow, compression disabled\n");
429 } else {
430 printk(KERN_INFO "btrfs: setting nodatacow\n");
431 }
432 info->compress_type = BTRFS_COMPRESS_NONE;
433 btrfs_clear_opt(info->mount_opt, COMPRESS);
434 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
435 btrfs_set_opt(info->mount_opt, NODATACOW);
436 btrfs_set_opt(info->mount_opt, NODATASUM);
437 break;
438 case Opt_compress_force:
439 case Opt_compress_force_type:
440 compress_force = true;
441 case Opt_compress:
442 case Opt_compress_type:
443 if (token == Opt_compress ||
444 token == Opt_compress_force ||
445 strcmp(args[0].from, "zlib") == 0) {
446 compress_type = "zlib";
447 info->compress_type = BTRFS_COMPRESS_ZLIB;
448 btrfs_set_opt(info->mount_opt, COMPRESS);
449 btrfs_clear_opt(info->mount_opt, NODATACOW);
450 btrfs_clear_opt(info->mount_opt, NODATASUM);
451 } else if (strcmp(args[0].from, "lzo") == 0) {
452 compress_type = "lzo";
453 info->compress_type = BTRFS_COMPRESS_LZO;
454 btrfs_set_opt(info->mount_opt, COMPRESS);
455 btrfs_clear_opt(info->mount_opt, NODATACOW);
456 btrfs_clear_opt(info->mount_opt, NODATASUM);
457 btrfs_set_fs_incompat(info, COMPRESS_LZO);
458 } else if (strncmp(args[0].from, "no", 2) == 0) {
459 compress_type = "no";
460 info->compress_type = BTRFS_COMPRESS_NONE;
461 btrfs_clear_opt(info->mount_opt, COMPRESS);
462 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
463 compress_force = false;
464 } else {
465 ret = -EINVAL;
466 goto out;
467 }
468
469 if (compress_force) {
470 btrfs_set_opt(info->mount_opt, FORCE_COMPRESS);
471 pr_info("btrfs: force %s compression\n",
472 compress_type);
473 } else
474 pr_info("btrfs: use %s compression\n",
475 compress_type);
476 break;
477 case Opt_ssd:
478 printk(KERN_INFO "btrfs: use ssd allocation scheme\n");
479 btrfs_set_opt(info->mount_opt, SSD);
480 break;
481 case Opt_ssd_spread:
482 printk(KERN_INFO "btrfs: use spread ssd "
483 "allocation scheme\n");
484 btrfs_set_opt(info->mount_opt, SSD);
485 btrfs_set_opt(info->mount_opt, SSD_SPREAD);
486 break;
487 case Opt_nossd:
488 printk(KERN_INFO "btrfs: not using ssd allocation "
489 "scheme\n");
490 btrfs_set_opt(info->mount_opt, NOSSD);
491 btrfs_clear_opt(info->mount_opt, SSD);
492 btrfs_clear_opt(info->mount_opt, SSD_SPREAD);
493 break;
494 case Opt_nobarrier:
495 printk(KERN_INFO "btrfs: turning off barriers\n");
496 btrfs_set_opt(info->mount_opt, NOBARRIER);
497 break;
498 case Opt_thread_pool:
499 intarg = 0;
500 match_int(&args[0], &intarg);
501 if (intarg)
502 info->thread_pool_size = intarg;
503 break;
504 case Opt_max_inline:
505 num = match_strdup(&args[0]);
506 if (num) {
507 info->max_inline = memparse(num, NULL);
508 kfree(num);
509
510 if (info->max_inline) {
511 info->max_inline = max_t(u64,
512 info->max_inline,
513 root->sectorsize);
514 }
515 printk(KERN_INFO "btrfs: max_inline at %llu\n",
516 (unsigned long long)info->max_inline);
517 }
518 break;
519 case Opt_alloc_start:
520 num = match_strdup(&args[0]);
521 if (num) {
522 info->alloc_start = memparse(num, NULL);
523 kfree(num);
524 printk(KERN_INFO
525 "btrfs: allocations start at %llu\n",
526 (unsigned long long)info->alloc_start);
527 }
528 break;
529 case Opt_noacl:
530 root->fs_info->sb->s_flags &= ~MS_POSIXACL;
531 break;
532 case Opt_notreelog:
533 printk(KERN_INFO "btrfs: disabling tree log\n");
534 btrfs_set_opt(info->mount_opt, NOTREELOG);
535 break;
536 case Opt_flushoncommit:
537 printk(KERN_INFO "btrfs: turning on flush-on-commit\n");
538 btrfs_set_opt(info->mount_opt, FLUSHONCOMMIT);
539 break;
540 case Opt_ratio:
541 intarg = 0;
542 match_int(&args[0], &intarg);
543 if (intarg) {
544 info->metadata_ratio = intarg;
545 printk(KERN_INFO "btrfs: metadata ratio %d\n",
546 info->metadata_ratio);
547 }
548 break;
549 case Opt_discard:
550 btrfs_set_opt(info->mount_opt, DISCARD);
551 break;
552 case Opt_space_cache:
553 btrfs_set_opt(info->mount_opt, SPACE_CACHE);
554 break;
555 case Opt_no_space_cache:
556 printk(KERN_INFO "btrfs: disabling disk space caching\n");
557 btrfs_clear_opt(info->mount_opt, SPACE_CACHE);
558 break;
559 case Opt_inode_cache:
560 printk(KERN_INFO "btrfs: enabling inode map caching\n");
561 btrfs_set_opt(info->mount_opt, INODE_MAP_CACHE);
562 break;
563 case Opt_clear_cache:
564 printk(KERN_INFO "btrfs: force clearing of disk cache\n");
565 btrfs_set_opt(info->mount_opt, CLEAR_CACHE);
566 break;
567 case Opt_user_subvol_rm_allowed:
568 btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
569 break;
570 case Opt_enospc_debug:
571 btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
572 break;
573 case Opt_defrag:
574 printk(KERN_INFO "btrfs: enabling auto defrag\n");
575 btrfs_set_opt(info->mount_opt, AUTO_DEFRAG);
576 break;
577 case Opt_recovery:
578 printk(KERN_INFO "btrfs: enabling auto recovery\n");
579 btrfs_set_opt(info->mount_opt, RECOVERY);
580 break;
581 case Opt_skip_balance:
582 btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
583 break;
584 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
585 case Opt_check_integrity_including_extent_data:
586 printk(KERN_INFO "btrfs: enabling check integrity"
587 " including extent data\n");
588 btrfs_set_opt(info->mount_opt,
589 CHECK_INTEGRITY_INCLUDING_EXTENT_DATA);
590 btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
591 break;
592 case Opt_check_integrity:
593 printk(KERN_INFO "btrfs: enabling check integrity\n");
594 btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
595 break;
596 case Opt_check_integrity_print_mask:
597 intarg = 0;
598 match_int(&args[0], &intarg);
599 if (intarg) {
600 info->check_integrity_print_mask = intarg;
601 printk(KERN_INFO "btrfs:"
602 " check_integrity_print_mask 0x%x\n",
603 info->check_integrity_print_mask);
604 }
605 break;
606 #else
607 case Opt_check_integrity_including_extent_data:
608 case Opt_check_integrity:
609 case Opt_check_integrity_print_mask:
610 printk(KERN_ERR "btrfs: support for check_integrity*"
611 " not compiled in!\n");
612 ret = -EINVAL;
613 goto out;
614 #endif
615 case Opt_fatal_errors:
616 if (strcmp(args[0].from, "panic") == 0)
617 btrfs_set_opt(info->mount_opt,
618 PANIC_ON_FATAL_ERROR);
619 else if (strcmp(args[0].from, "bug") == 0)
620 btrfs_clear_opt(info->mount_opt,
621 PANIC_ON_FATAL_ERROR);
622 else {
623 ret = -EINVAL;
624 goto out;
625 }
626 break;
627 case Opt_err:
628 printk(KERN_INFO "btrfs: unrecognized mount option "
629 "'%s'\n", p);
630 ret = -EINVAL;
631 goto out;
632 default:
633 break;
634 }
635 }
636 out:
637 if (!ret && btrfs_test_opt(root, SPACE_CACHE))
638 printk(KERN_INFO "btrfs: disk space caching is enabled\n");
639 kfree(orig);
640 return ret;
641 }
642
643 /*
644 * Parse mount options that are required early in the mount process.
645 *
646 * All other options will be parsed on much later in the mount process and
647 * only when we need to allocate a new super block.
648 */
649 static int btrfs_parse_early_options(const char *options, fmode_t flags,
650 void *holder, char **subvol_name, u64 *subvol_objectid,
651 u64 *subvol_rootid, struct btrfs_fs_devices **fs_devices)
652 {
653 substring_t args[MAX_OPT_ARGS];
654 char *device_name, *opts, *orig, *p;
655 int error = 0;
656 int intarg;
657
658 if (!options)
659 return 0;
660
661 /*
662 * strsep changes the string, duplicate it because parse_options
663 * gets called twice
664 */
665 opts = kstrdup(options, GFP_KERNEL);
666 if (!opts)
667 return -ENOMEM;
668 orig = opts;
669
670 while ((p = strsep(&opts, ",")) != NULL) {
671 int token;
672 if (!*p)
673 continue;
674
675 token = match_token(p, tokens, args);
676 switch (token) {
677 case Opt_subvol:
678 kfree(*subvol_name);
679 *subvol_name = match_strdup(&args[0]);
680 break;
681 case Opt_subvolid:
682 intarg = 0;
683 error = match_int(&args[0], &intarg);
684 if (!error) {
685 /* we want the original fs_tree */
686 if (!intarg)
687 *subvol_objectid =
688 BTRFS_FS_TREE_OBJECTID;
689 else
690 *subvol_objectid = intarg;
691 }
692 break;
693 case Opt_subvolrootid:
694 intarg = 0;
695 error = match_int(&args[0], &intarg);
696 if (!error) {
697 /* we want the original fs_tree */
698 if (!intarg)
699 *subvol_rootid =
700 BTRFS_FS_TREE_OBJECTID;
701 else
702 *subvol_rootid = intarg;
703 }
704 break;
705 case Opt_device:
706 device_name = match_strdup(&args[0]);
707 if (!device_name) {
708 error = -ENOMEM;
709 goto out;
710 }
711 error = btrfs_scan_one_device(device_name,
712 flags, holder, fs_devices);
713 kfree(device_name);
714 if (error)
715 goto out;
716 break;
717 default:
718 break;
719 }
720 }
721
722 out:
723 kfree(orig);
724 return error;
725 }
726
727 static struct dentry *get_default_root(struct super_block *sb,
728 u64 subvol_objectid)
729 {
730 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
731 struct btrfs_root *root = fs_info->tree_root;
732 struct btrfs_root *new_root;
733 struct btrfs_dir_item *di;
734 struct btrfs_path *path;
735 struct btrfs_key location;
736 struct inode *inode;
737 u64 dir_id;
738 int new = 0;
739
740 /*
741 * We have a specific subvol we want to mount, just setup location and
742 * go look up the root.
743 */
744 if (subvol_objectid) {
745 location.objectid = subvol_objectid;
746 location.type = BTRFS_ROOT_ITEM_KEY;
747 location.offset = (u64)-1;
748 goto find_root;
749 }
750
751 path = btrfs_alloc_path();
752 if (!path)
753 return ERR_PTR(-ENOMEM);
754 path->leave_spinning = 1;
755
756 /*
757 * Find the "default" dir item which points to the root item that we
758 * will mount by default if we haven't been given a specific subvolume
759 * to mount.
760 */
761 dir_id = btrfs_super_root_dir(fs_info->super_copy);
762 di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
763 if (IS_ERR(di)) {
764 btrfs_free_path(path);
765 return ERR_CAST(di);
766 }
767 if (!di) {
768 /*
769 * Ok the default dir item isn't there. This is weird since
770 * it's always been there, but don't freak out, just try and
771 * mount to root most subvolume.
772 */
773 btrfs_free_path(path);
774 dir_id = BTRFS_FIRST_FREE_OBJECTID;
775 new_root = fs_info->fs_root;
776 goto setup_root;
777 }
778
779 btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
780 btrfs_free_path(path);
781
782 find_root:
783 new_root = btrfs_read_fs_root_no_name(fs_info, &location);
784 if (IS_ERR(new_root))
785 return ERR_CAST(new_root);
786
787 if (btrfs_root_refs(&new_root->root_item) == 0)
788 return ERR_PTR(-ENOENT);
789
790 dir_id = btrfs_root_dirid(&new_root->root_item);
791 setup_root:
792 location.objectid = dir_id;
793 location.type = BTRFS_INODE_ITEM_KEY;
794 location.offset = 0;
795
796 inode = btrfs_iget(sb, &location, new_root, &new);
797 if (IS_ERR(inode))
798 return ERR_CAST(inode);
799
800 /*
801 * If we're just mounting the root most subvol put the inode and return
802 * a reference to the dentry. We will have already gotten a reference
803 * to the inode in btrfs_fill_super so we're good to go.
804 */
805 if (!new && sb->s_root->d_inode == inode) {
806 iput(inode);
807 return dget(sb->s_root);
808 }
809
810 return d_obtain_alias(inode);
811 }
812
813 static int btrfs_fill_super(struct super_block *sb,
814 struct btrfs_fs_devices *fs_devices,
815 void *data, int silent)
816 {
817 struct inode *inode;
818 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
819 struct btrfs_key key;
820 int err;
821
822 sb->s_maxbytes = MAX_LFS_FILESIZE;
823 sb->s_magic = BTRFS_SUPER_MAGIC;
824 sb->s_op = &btrfs_super_ops;
825 sb->s_d_op = &btrfs_dentry_operations;
826 sb->s_export_op = &btrfs_export_ops;
827 sb->s_xattr = btrfs_xattr_handlers;
828 sb->s_time_gran = 1;
829 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
830 sb->s_flags |= MS_POSIXACL;
831 #endif
832 sb->s_flags |= MS_I_VERSION;
833 err = open_ctree(sb, fs_devices, (char *)data);
834 if (err) {
835 printk("btrfs: open_ctree failed\n");
836 return err;
837 }
838
839 key.objectid = BTRFS_FIRST_FREE_OBJECTID;
840 key.type = BTRFS_INODE_ITEM_KEY;
841 key.offset = 0;
842 inode = btrfs_iget(sb, &key, fs_info->fs_root, NULL);
843 if (IS_ERR(inode)) {
844 err = PTR_ERR(inode);
845 goto fail_close;
846 }
847
848 sb->s_root = d_make_root(inode);
849 if (!sb->s_root) {
850 err = -ENOMEM;
851 goto fail_close;
852 }
853
854 save_mount_options(sb, data);
855 cleancache_init_fs(sb);
856 sb->s_flags |= MS_ACTIVE;
857 return 0;
858
859 fail_close:
860 close_ctree(fs_info->tree_root);
861 return err;
862 }
863
864 int btrfs_sync_fs(struct super_block *sb, int wait)
865 {
866 struct btrfs_trans_handle *trans;
867 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
868 struct btrfs_root *root = fs_info->tree_root;
869
870 trace_btrfs_sync_fs(wait);
871
872 if (!wait) {
873 filemap_flush(fs_info->btree_inode->i_mapping);
874 return 0;
875 }
876
877 btrfs_wait_ordered_extents(root, 0);
878
879 trans = btrfs_attach_transaction(root);
880 if (IS_ERR(trans)) {
881 /* no transaction, don't bother */
882 if (PTR_ERR(trans) == -ENOENT)
883 return 0;
884 return PTR_ERR(trans);
885 }
886 return btrfs_commit_transaction(trans, root);
887 }
888
889 static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
890 {
891 struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
892 struct btrfs_root *root = info->tree_root;
893 char *compress_type;
894
895 if (btrfs_test_opt(root, DEGRADED))
896 seq_puts(seq, ",degraded");
897 if (btrfs_test_opt(root, NODATASUM))
898 seq_puts(seq, ",nodatasum");
899 if (btrfs_test_opt(root, NODATACOW))
900 seq_puts(seq, ",nodatacow");
901 if (btrfs_test_opt(root, NOBARRIER))
902 seq_puts(seq, ",nobarrier");
903 if (info->max_inline != 8192 * 1024)
904 seq_printf(seq, ",max_inline=%llu",
905 (unsigned long long)info->max_inline);
906 if (info->alloc_start != 0)
907 seq_printf(seq, ",alloc_start=%llu",
908 (unsigned long long)info->alloc_start);
909 if (info->thread_pool_size != min_t(unsigned long,
910 num_online_cpus() + 2, 8))
911 seq_printf(seq, ",thread_pool=%d", info->thread_pool_size);
912 if (btrfs_test_opt(root, COMPRESS)) {
913 if (info->compress_type == BTRFS_COMPRESS_ZLIB)
914 compress_type = "zlib";
915 else
916 compress_type = "lzo";
917 if (btrfs_test_opt(root, FORCE_COMPRESS))
918 seq_printf(seq, ",compress-force=%s", compress_type);
919 else
920 seq_printf(seq, ",compress=%s", compress_type);
921 }
922 if (btrfs_test_opt(root, NOSSD))
923 seq_puts(seq, ",nossd");
924 if (btrfs_test_opt(root, SSD_SPREAD))
925 seq_puts(seq, ",ssd_spread");
926 else if (btrfs_test_opt(root, SSD))
927 seq_puts(seq, ",ssd");
928 if (btrfs_test_opt(root, NOTREELOG))
929 seq_puts(seq, ",notreelog");
930 if (btrfs_test_opt(root, FLUSHONCOMMIT))
931 seq_puts(seq, ",flushoncommit");
932 if (btrfs_test_opt(root, DISCARD))
933 seq_puts(seq, ",discard");
934 if (!(root->fs_info->sb->s_flags & MS_POSIXACL))
935 seq_puts(seq, ",noacl");
936 if (btrfs_test_opt(root, SPACE_CACHE))
937 seq_puts(seq, ",space_cache");
938 else
939 seq_puts(seq, ",nospace_cache");
940 if (btrfs_test_opt(root, CLEAR_CACHE))
941 seq_puts(seq, ",clear_cache");
942 if (btrfs_test_opt(root, USER_SUBVOL_RM_ALLOWED))
943 seq_puts(seq, ",user_subvol_rm_allowed");
944 if (btrfs_test_opt(root, ENOSPC_DEBUG))
945 seq_puts(seq, ",enospc_debug");
946 if (btrfs_test_opt(root, AUTO_DEFRAG))
947 seq_puts(seq, ",autodefrag");
948 if (btrfs_test_opt(root, INODE_MAP_CACHE))
949 seq_puts(seq, ",inode_cache");
950 if (btrfs_test_opt(root, SKIP_BALANCE))
951 seq_puts(seq, ",skip_balance");
952 if (btrfs_test_opt(root, PANIC_ON_FATAL_ERROR))
953 seq_puts(seq, ",fatal_errors=panic");
954 return 0;
955 }
956
957 static int btrfs_test_super(struct super_block *s, void *data)
958 {
959 struct btrfs_fs_info *p = data;
960 struct btrfs_fs_info *fs_info = btrfs_sb(s);
961
962 return fs_info->fs_devices == p->fs_devices;
963 }
964
965 static int btrfs_set_super(struct super_block *s, void *data)
966 {
967 int err = set_anon_super(s, data);
968 if (!err)
969 s->s_fs_info = data;
970 return err;
971 }
972
973 /*
974 * subvolumes are identified by ino 256
975 */
976 static inline int is_subvolume_inode(struct inode *inode)
977 {
978 if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
979 return 1;
980 return 0;
981 }
982
983 /*
984 * This will strip out the subvol=%s argument for an argument string and add
985 * subvolid=0 to make sure we get the actual tree root for path walking to the
986 * subvol we want.
987 */
988 static char *setup_root_args(char *args)
989 {
990 unsigned len = strlen(args) + 2 + 1;
991 char *src, *dst, *buf;
992
993 /*
994 * We need the same args as before, but with this substitution:
995 * s!subvol=[^,]+!subvolid=0!
996 *
997 * Since the replacement string is up to 2 bytes longer than the
998 * original, allocate strlen(args) + 2 + 1 bytes.
999 */
1000
1001 src = strstr(args, "subvol=");
1002 /* This shouldn't happen, but just in case.. */
1003 if (!src)
1004 return NULL;
1005
1006 buf = dst = kmalloc(len, GFP_NOFS);
1007 if (!buf)
1008 return NULL;
1009
1010 /*
1011 * If the subvol= arg is not at the start of the string,
1012 * copy whatever precedes it into buf.
1013 */
1014 if (src != args) {
1015 *src++ = '\0';
1016 strcpy(buf, args);
1017 dst += strlen(args);
1018 }
1019
1020 strcpy(dst, "subvolid=0");
1021 dst += strlen("subvolid=0");
1022
1023 /*
1024 * If there is a "," after the original subvol=... string,
1025 * copy that suffix into our buffer. Otherwise, we're done.
1026 */
1027 src = strchr(src, ',');
1028 if (src)
1029 strcpy(dst, src);
1030
1031 return buf;
1032 }
1033
1034 static struct dentry *mount_subvol(const char *subvol_name, int flags,
1035 const char *device_name, char *data)
1036 {
1037 struct dentry *root;
1038 struct vfsmount *mnt;
1039 char *newargs;
1040
1041 newargs = setup_root_args(data);
1042 if (!newargs)
1043 return ERR_PTR(-ENOMEM);
1044 mnt = vfs_kern_mount(&btrfs_fs_type, flags, device_name,
1045 newargs);
1046 kfree(newargs);
1047 if (IS_ERR(mnt))
1048 return ERR_CAST(mnt);
1049
1050 root = mount_subtree(mnt, subvol_name);
1051
1052 if (!IS_ERR(root) && !is_subvolume_inode(root->d_inode)) {
1053 struct super_block *s = root->d_sb;
1054 dput(root);
1055 root = ERR_PTR(-EINVAL);
1056 deactivate_locked_super(s);
1057 printk(KERN_ERR "btrfs: '%s' is not a valid subvolume\n",
1058 subvol_name);
1059 }
1060
1061 return root;
1062 }
1063
1064 /*
1065 * Find a superblock for the given device / mount point.
1066 *
1067 * Note: This is based on get_sb_bdev from fs/super.c with a few additions
1068 * for multiple device setup. Make sure to keep it in sync.
1069 */
1070 static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
1071 const char *device_name, void *data)
1072 {
1073 struct block_device *bdev = NULL;
1074 struct super_block *s;
1075 struct dentry *root;
1076 struct btrfs_fs_devices *fs_devices = NULL;
1077 struct btrfs_fs_info *fs_info = NULL;
1078 fmode_t mode = FMODE_READ;
1079 char *subvol_name = NULL;
1080 u64 subvol_objectid = 0;
1081 u64 subvol_rootid = 0;
1082 int error = 0;
1083
1084 if (!(flags & MS_RDONLY))
1085 mode |= FMODE_WRITE;
1086
1087 error = btrfs_parse_early_options(data, mode, fs_type,
1088 &subvol_name, &subvol_objectid,
1089 &subvol_rootid, &fs_devices);
1090 if (error) {
1091 kfree(subvol_name);
1092 return ERR_PTR(error);
1093 }
1094
1095 if (subvol_name) {
1096 root = mount_subvol(subvol_name, flags, device_name, data);
1097 kfree(subvol_name);
1098 return root;
1099 }
1100
1101 error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices);
1102 if (error)
1103 return ERR_PTR(error);
1104
1105 /*
1106 * Setup a dummy root and fs_info for test/set super. This is because
1107 * we don't actually fill this stuff out until open_ctree, but we need
1108 * it for searching for existing supers, so this lets us do that and
1109 * then open_ctree will properly initialize everything later.
1110 */
1111 fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_NOFS);
1112 if (!fs_info)
1113 return ERR_PTR(-ENOMEM);
1114
1115 fs_info->fs_devices = fs_devices;
1116
1117 fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
1118 fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
1119 if (!fs_info->super_copy || !fs_info->super_for_commit) {
1120 error = -ENOMEM;
1121 goto error_fs_info;
1122 }
1123
1124 error = btrfs_open_devices(fs_devices, mode, fs_type);
1125 if (error)
1126 goto error_fs_info;
1127
1128 if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
1129 error = -EACCES;
1130 goto error_close_devices;
1131 }
1132
1133 bdev = fs_devices->latest_bdev;
1134 s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | MS_NOSEC,
1135 fs_info);
1136 if (IS_ERR(s)) {
1137 error = PTR_ERR(s);
1138 goto error_close_devices;
1139 }
1140
1141 if (s->s_root) {
1142 btrfs_close_devices(fs_devices);
1143 free_fs_info(fs_info);
1144 if ((flags ^ s->s_flags) & MS_RDONLY)
1145 error = -EBUSY;
1146 } else {
1147 char b[BDEVNAME_SIZE];
1148
1149 strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
1150 btrfs_sb(s)->bdev_holder = fs_type;
1151 error = btrfs_fill_super(s, fs_devices, data,
1152 flags & MS_SILENT ? 1 : 0);
1153 }
1154
1155 root = !error ? get_default_root(s, subvol_objectid) : ERR_PTR(error);
1156 if (IS_ERR(root))
1157 deactivate_locked_super(s);
1158
1159 return root;
1160
1161 error_close_devices:
1162 btrfs_close_devices(fs_devices);
1163 error_fs_info:
1164 free_fs_info(fs_info);
1165 return ERR_PTR(error);
1166 }
1167
1168 static void btrfs_set_max_workers(struct btrfs_workers *workers, int new_limit)
1169 {
1170 spin_lock_irq(&workers->lock);
1171 workers->max_workers = new_limit;
1172 spin_unlock_irq(&workers->lock);
1173 }
1174
1175 static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
1176 int new_pool_size, int old_pool_size)
1177 {
1178 if (new_pool_size == old_pool_size)
1179 return;
1180
1181 fs_info->thread_pool_size = new_pool_size;
1182
1183 printk(KERN_INFO "btrfs: resize thread pool %d -> %d\n",
1184 old_pool_size, new_pool_size);
1185
1186 btrfs_set_max_workers(&fs_info->generic_worker, new_pool_size);
1187 btrfs_set_max_workers(&fs_info->workers, new_pool_size);
1188 btrfs_set_max_workers(&fs_info->delalloc_workers, new_pool_size);
1189 btrfs_set_max_workers(&fs_info->submit_workers, new_pool_size);
1190 btrfs_set_max_workers(&fs_info->caching_workers, new_pool_size);
1191 btrfs_set_max_workers(&fs_info->fixup_workers, new_pool_size);
1192 btrfs_set_max_workers(&fs_info->endio_workers, new_pool_size);
1193 btrfs_set_max_workers(&fs_info->endio_meta_workers, new_pool_size);
1194 btrfs_set_max_workers(&fs_info->endio_meta_write_workers, new_pool_size);
1195 btrfs_set_max_workers(&fs_info->endio_write_workers, new_pool_size);
1196 btrfs_set_max_workers(&fs_info->endio_freespace_worker, new_pool_size);
1197 btrfs_set_max_workers(&fs_info->delayed_workers, new_pool_size);
1198 btrfs_set_max_workers(&fs_info->readahead_workers, new_pool_size);
1199 btrfs_set_max_workers(&fs_info->scrub_wr_completion_workers,
1200 new_pool_size);
1201 }
1202
1203 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
1204 {
1205 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1206 struct btrfs_root *root = fs_info->tree_root;
1207 unsigned old_flags = sb->s_flags;
1208 unsigned long old_opts = fs_info->mount_opt;
1209 unsigned long old_compress_type = fs_info->compress_type;
1210 u64 old_max_inline = fs_info->max_inline;
1211 u64 old_alloc_start = fs_info->alloc_start;
1212 int old_thread_pool_size = fs_info->thread_pool_size;
1213 unsigned int old_metadata_ratio = fs_info->metadata_ratio;
1214 int ret;
1215
1216 ret = btrfs_parse_options(root, data);
1217 if (ret) {
1218 ret = -EINVAL;
1219 goto restore;
1220 }
1221
1222 btrfs_resize_thread_pool(fs_info,
1223 fs_info->thread_pool_size, old_thread_pool_size);
1224
1225 if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1226 return 0;
1227
1228 if (*flags & MS_RDONLY) {
1229 /*
1230 * this also happens on 'umount -rf' or on shutdown, when
1231 * the filesystem is busy.
1232 */
1233 sb->s_flags |= MS_RDONLY;
1234
1235 btrfs_dev_replace_suspend_for_unmount(fs_info);
1236 btrfs_scrub_cancel(fs_info);
1237
1238 ret = btrfs_commit_super(root);
1239 if (ret)
1240 goto restore;
1241 } else {
1242 if (fs_info->fs_devices->rw_devices == 0) {
1243 ret = -EACCES;
1244 goto restore;
1245 }
1246
1247 if (fs_info->fs_devices->missing_devices >
1248 fs_info->num_tolerated_disk_barrier_failures &&
1249 !(*flags & MS_RDONLY)) {
1250 printk(KERN_WARNING
1251 "Btrfs: too many missing devices, writeable remount is not allowed\n");
1252 ret = -EACCES;
1253 goto restore;
1254 }
1255
1256 if (btrfs_super_log_root(fs_info->super_copy) != 0) {
1257 ret = -EINVAL;
1258 goto restore;
1259 }
1260
1261 ret = btrfs_cleanup_fs_roots(fs_info);
1262 if (ret)
1263 goto restore;
1264
1265 /* recover relocation */
1266 ret = btrfs_recover_relocation(root);
1267 if (ret)
1268 goto restore;
1269
1270 ret = btrfs_resume_balance_async(fs_info);
1271 if (ret)
1272 goto restore;
1273
1274 ret = btrfs_resume_dev_replace_async(fs_info);
1275 if (ret) {
1276 pr_warn("btrfs: failed to resume dev_replace\n");
1277 goto restore;
1278 }
1279 sb->s_flags &= ~MS_RDONLY;
1280 }
1281
1282 return 0;
1283
1284 restore:
1285 /* We've hit an error - don't reset MS_RDONLY */
1286 if (sb->s_flags & MS_RDONLY)
1287 old_flags |= MS_RDONLY;
1288 sb->s_flags = old_flags;
1289 fs_info->mount_opt = old_opts;
1290 fs_info->compress_type = old_compress_type;
1291 fs_info->max_inline = old_max_inline;
1292 fs_info->alloc_start = old_alloc_start;
1293 btrfs_resize_thread_pool(fs_info,
1294 old_thread_pool_size, fs_info->thread_pool_size);
1295 fs_info->metadata_ratio = old_metadata_ratio;
1296 return ret;
1297 }
1298
1299 /* Used to sort the devices by max_avail(descending sort) */
1300 static int btrfs_cmp_device_free_bytes(const void *dev_info1,
1301 const void *dev_info2)
1302 {
1303 if (((struct btrfs_device_info *)dev_info1)->max_avail >
1304 ((struct btrfs_device_info *)dev_info2)->max_avail)
1305 return -1;
1306 else if (((struct btrfs_device_info *)dev_info1)->max_avail <
1307 ((struct btrfs_device_info *)dev_info2)->max_avail)
1308 return 1;
1309 else
1310 return 0;
1311 }
1312
1313 /*
1314 * sort the devices by max_avail, in which max free extent size of each device
1315 * is stored.(Descending Sort)
1316 */
1317 static inline void btrfs_descending_sort_devices(
1318 struct btrfs_device_info *devices,
1319 size_t nr_devices)
1320 {
1321 sort(devices, nr_devices, sizeof(struct btrfs_device_info),
1322 btrfs_cmp_device_free_bytes, NULL);
1323 }
1324
1325 /*
1326 * The helper to calc the free space on the devices that can be used to store
1327 * file data.
1328 */
1329 static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes)
1330 {
1331 struct btrfs_fs_info *fs_info = root->fs_info;
1332 struct btrfs_device_info *devices_info;
1333 struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
1334 struct btrfs_device *device;
1335 u64 skip_space;
1336 u64 type;
1337 u64 avail_space;
1338 u64 used_space;
1339 u64 min_stripe_size;
1340 int min_stripes = 1, num_stripes = 1;
1341 int i = 0, nr_devices;
1342 int ret;
1343
1344 nr_devices = fs_info->fs_devices->open_devices;
1345 BUG_ON(!nr_devices);
1346
1347 devices_info = kmalloc(sizeof(*devices_info) * nr_devices,
1348 GFP_NOFS);
1349 if (!devices_info)
1350 return -ENOMEM;
1351
1352 /* calc min stripe number for data space alloction */
1353 type = btrfs_get_alloc_profile(root, 1);
1354 if (type & BTRFS_BLOCK_GROUP_RAID0) {
1355 min_stripes = 2;
1356 num_stripes = nr_devices;
1357 } else if (type & BTRFS_BLOCK_GROUP_RAID1) {
1358 min_stripes = 2;
1359 num_stripes = 2;
1360 } else if (type & BTRFS_BLOCK_GROUP_RAID10) {
1361 min_stripes = 4;
1362 num_stripes = 4;
1363 }
1364
1365 if (type & BTRFS_BLOCK_GROUP_DUP)
1366 min_stripe_size = 2 * BTRFS_STRIPE_LEN;
1367 else
1368 min_stripe_size = BTRFS_STRIPE_LEN;
1369
1370 list_for_each_entry(device, &fs_devices->devices, dev_list) {
1371 if (!device->in_fs_metadata || !device->bdev ||
1372 device->is_tgtdev_for_dev_replace)
1373 continue;
1374
1375 avail_space = device->total_bytes - device->bytes_used;
1376
1377 /* align with stripe_len */
1378 do_div(avail_space, BTRFS_STRIPE_LEN);
1379 avail_space *= BTRFS_STRIPE_LEN;
1380
1381 /*
1382 * In order to avoid overwritting the superblock on the drive,
1383 * btrfs starts at an offset of at least 1MB when doing chunk
1384 * allocation.
1385 */
1386 skip_space = 1024 * 1024;
1387
1388 /* user can set the offset in fs_info->alloc_start. */
1389 if (fs_info->alloc_start + BTRFS_STRIPE_LEN <=
1390 device->total_bytes)
1391 skip_space = max(fs_info->alloc_start, skip_space);
1392
1393 /*
1394 * btrfs can not use the free space in [0, skip_space - 1],
1395 * we must subtract it from the total. In order to implement
1396 * it, we account the used space in this range first.
1397 */
1398 ret = btrfs_account_dev_extents_size(device, 0, skip_space - 1,
1399 &used_space);
1400 if (ret) {
1401 kfree(devices_info);
1402 return ret;
1403 }
1404
1405 /* calc the free space in [0, skip_space - 1] */
1406 skip_space -= used_space;
1407
1408 /*
1409 * we can use the free space in [0, skip_space - 1], subtract
1410 * it from the total.
1411 */
1412 if (avail_space && avail_space >= skip_space)
1413 avail_space -= skip_space;
1414 else
1415 avail_space = 0;
1416
1417 if (avail_space < min_stripe_size)
1418 continue;
1419
1420 devices_info[i].dev = device;
1421 devices_info[i].max_avail = avail_space;
1422
1423 i++;
1424 }
1425
1426 nr_devices = i;
1427
1428 btrfs_descending_sort_devices(devices_info, nr_devices);
1429
1430 i = nr_devices - 1;
1431 avail_space = 0;
1432 while (nr_devices >= min_stripes) {
1433 if (num_stripes > nr_devices)
1434 num_stripes = nr_devices;
1435
1436 if (devices_info[i].max_avail >= min_stripe_size) {
1437 int j;
1438 u64 alloc_size;
1439
1440 avail_space += devices_info[i].max_avail * num_stripes;
1441 alloc_size = devices_info[i].max_avail;
1442 for (j = i + 1 - num_stripes; j <= i; j++)
1443 devices_info[j].max_avail -= alloc_size;
1444 }
1445 i--;
1446 nr_devices--;
1447 }
1448
1449 kfree(devices_info);
1450 *free_bytes = avail_space;
1451 return 0;
1452 }
1453
1454 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
1455 {
1456 struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
1457 struct btrfs_super_block *disk_super = fs_info->super_copy;
1458 struct list_head *head = &fs_info->space_info;
1459 struct btrfs_space_info *found;
1460 u64 total_used = 0;
1461 u64 total_free_data = 0;
1462 int bits = dentry->d_sb->s_blocksize_bits;
1463 __be32 *fsid = (__be32 *)fs_info->fsid;
1464 int ret;
1465
1466 /* holding chunk_muext to avoid allocating new chunks */
1467 mutex_lock(&fs_info->chunk_mutex);
1468 rcu_read_lock();
1469 list_for_each_entry_rcu(found, head, list) {
1470 if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
1471 total_free_data += found->disk_total - found->disk_used;
1472 total_free_data -=
1473 btrfs_account_ro_block_groups_free_space(found);
1474 }
1475
1476 total_used += found->disk_used;
1477 }
1478 rcu_read_unlock();
1479
1480 buf->f_namelen = BTRFS_NAME_LEN;
1481 buf->f_blocks = btrfs_super_total_bytes(disk_super) >> bits;
1482 buf->f_bfree = buf->f_blocks - (total_used >> bits);
1483 buf->f_bsize = dentry->d_sb->s_blocksize;
1484 buf->f_type = BTRFS_SUPER_MAGIC;
1485 buf->f_bavail = total_free_data;
1486 ret = btrfs_calc_avail_data_space(fs_info->tree_root, &total_free_data);
1487 if (ret) {
1488 mutex_unlock(&fs_info->chunk_mutex);
1489 return ret;
1490 }
1491 buf->f_bavail += total_free_data;
1492 buf->f_bavail = buf->f_bavail >> bits;
1493 mutex_unlock(&fs_info->chunk_mutex);
1494
1495 /* We treat it as constant endianness (it doesn't matter _which_)
1496 because we want the fsid to come out the same whether mounted
1497 on a big-endian or little-endian host */
1498 buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
1499 buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
1500 /* Mask in the root object ID too, to disambiguate subvols */
1501 buf->f_fsid.val[0] ^= BTRFS_I(dentry->d_inode)->root->objectid >> 32;
1502 buf->f_fsid.val[1] ^= BTRFS_I(dentry->d_inode)->root->objectid;
1503
1504 return 0;
1505 }
1506
1507 static void btrfs_kill_super(struct super_block *sb)
1508 {
1509 struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1510 kill_anon_super(sb);
1511 free_fs_info(fs_info);
1512 }
1513
1514 static struct file_system_type btrfs_fs_type = {
1515 .owner = THIS_MODULE,
1516 .name = "btrfs",
1517 .mount = btrfs_mount,
1518 .kill_sb = btrfs_kill_super,
1519 .fs_flags = FS_REQUIRES_DEV,
1520 };
1521
1522 /*
1523 * used by btrfsctl to scan devices when no FS is mounted
1524 */
1525 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
1526 unsigned long arg)
1527 {
1528 struct btrfs_ioctl_vol_args *vol;
1529 struct btrfs_fs_devices *fs_devices;
1530 int ret = -ENOTTY;
1531
1532 if (!capable(CAP_SYS_ADMIN))
1533 return -EPERM;
1534
1535 vol = memdup_user((void __user *)arg, sizeof(*vol));
1536 if (IS_ERR(vol))
1537 return PTR_ERR(vol);
1538
1539 switch (cmd) {
1540 case BTRFS_IOC_SCAN_DEV:
1541 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
1542 &btrfs_fs_type, &fs_devices);
1543 break;
1544 case BTRFS_IOC_DEVICES_READY:
1545 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
1546 &btrfs_fs_type, &fs_devices);
1547 if (ret)
1548 break;
1549 ret = !(fs_devices->num_devices == fs_devices->total_devices);
1550 break;
1551 }
1552
1553 kfree(vol);
1554 return ret;
1555 }
1556
1557 static int btrfs_freeze(struct super_block *sb)
1558 {
1559 struct btrfs_trans_handle *trans;
1560 struct btrfs_root *root = btrfs_sb(sb)->tree_root;
1561
1562 trans = btrfs_attach_transaction(root);
1563 if (IS_ERR(trans)) {
1564 /* no transaction, don't bother */
1565 if (PTR_ERR(trans) == -ENOENT)
1566 return 0;
1567 return PTR_ERR(trans);
1568 }
1569 return btrfs_commit_transaction(trans, root);
1570 }
1571
1572 static int btrfs_unfreeze(struct super_block *sb)
1573 {
1574 return 0;
1575 }
1576
1577 static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
1578 {
1579 struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
1580 struct btrfs_fs_devices *cur_devices;
1581 struct btrfs_device *dev, *first_dev = NULL;
1582 struct list_head *head;
1583 struct rcu_string *name;
1584
1585 mutex_lock(&fs_info->fs_devices->device_list_mutex);
1586 cur_devices = fs_info->fs_devices;
1587 while (cur_devices) {
1588 head = &cur_devices->devices;
1589 list_for_each_entry(dev, head, dev_list) {
1590 if (dev->missing)
1591 continue;
1592 if (!first_dev || dev->devid < first_dev->devid)
1593 first_dev = dev;
1594 }
1595 cur_devices = cur_devices->seed;
1596 }
1597
1598 if (first_dev) {
1599 rcu_read_lock();
1600 name = rcu_dereference(first_dev->name);
1601 seq_escape(m, name->str, " \t\n\\");
1602 rcu_read_unlock();
1603 } else {
1604 WARN_ON(1);
1605 }
1606 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
1607 return 0;
1608 }
1609
1610 static const struct super_operations btrfs_super_ops = {
1611 .drop_inode = btrfs_drop_inode,
1612 .evict_inode = btrfs_evict_inode,
1613 .put_super = btrfs_put_super,
1614 .sync_fs = btrfs_sync_fs,
1615 .show_options = btrfs_show_options,
1616 .show_devname = btrfs_show_devname,
1617 .write_inode = btrfs_write_inode,
1618 .alloc_inode = btrfs_alloc_inode,
1619 .destroy_inode = btrfs_destroy_inode,
1620 .statfs = btrfs_statfs,
1621 .remount_fs = btrfs_remount,
1622 .freeze_fs = btrfs_freeze,
1623 .unfreeze_fs = btrfs_unfreeze,
1624 };
1625
1626 static const struct file_operations btrfs_ctl_fops = {
1627 .unlocked_ioctl = btrfs_control_ioctl,
1628 .compat_ioctl = btrfs_control_ioctl,
1629 .owner = THIS_MODULE,
1630 .llseek = noop_llseek,
1631 };
1632
1633 static struct miscdevice btrfs_misc = {
1634 .minor = BTRFS_MINOR,
1635 .name = "btrfs-control",
1636 .fops = &btrfs_ctl_fops
1637 };
1638
1639 MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
1640 MODULE_ALIAS("devname:btrfs-control");
1641
1642 static int btrfs_interface_init(void)
1643 {
1644 return misc_register(&btrfs_misc);
1645 }
1646
1647 static void btrfs_interface_exit(void)
1648 {
1649 if (misc_deregister(&btrfs_misc) < 0)
1650 printk(KERN_INFO "btrfs: misc_deregister failed for control device\n");
1651 }
1652
1653 static int __init init_btrfs_fs(void)
1654 {
1655 int err;
1656
1657 err = btrfs_init_sysfs();
1658 if (err)
1659 return err;
1660
1661 btrfs_init_compress();
1662
1663 err = btrfs_init_cachep();
1664 if (err)
1665 goto free_compress;
1666
1667 err = extent_io_init();
1668 if (err)
1669 goto free_cachep;
1670
1671 err = extent_map_init();
1672 if (err)
1673 goto free_extent_io;
1674
1675 err = ordered_data_init();
1676 if (err)
1677 goto free_extent_map;
1678
1679 err = btrfs_delayed_inode_init();
1680 if (err)
1681 goto free_ordered_data;
1682
1683 err = btrfs_auto_defrag_init();
1684 if (err)
1685 goto free_delayed_inode;
1686
1687 err = btrfs_interface_init();
1688 if (err)
1689 goto free_auto_defrag;
1690
1691 err = register_filesystem(&btrfs_fs_type);
1692 if (err)
1693 goto unregister_ioctl;
1694
1695 btrfs_init_lockdep();
1696
1697 printk(KERN_INFO "%s loaded\n", BTRFS_BUILD_VERSION);
1698 return 0;
1699
1700 unregister_ioctl:
1701 btrfs_interface_exit();
1702 free_auto_defrag:
1703 btrfs_auto_defrag_exit();
1704 free_delayed_inode:
1705 btrfs_delayed_inode_exit();
1706 free_ordered_data:
1707 ordered_data_exit();
1708 free_extent_map:
1709 extent_map_exit();
1710 free_extent_io:
1711 extent_io_exit();
1712 free_cachep:
1713 btrfs_destroy_cachep();
1714 free_compress:
1715 btrfs_exit_compress();
1716 btrfs_exit_sysfs();
1717 return err;
1718 }
1719
1720 static void __exit exit_btrfs_fs(void)
1721 {
1722 btrfs_destroy_cachep();
1723 btrfs_auto_defrag_exit();
1724 btrfs_delayed_inode_exit();
1725 ordered_data_exit();
1726 extent_map_exit();
1727 extent_io_exit();
1728 btrfs_interface_exit();
1729 unregister_filesystem(&btrfs_fs_type);
1730 btrfs_exit_sysfs();
1731 btrfs_cleanup_fs_uuids();
1732 btrfs_exit_compress();
1733 }
1734
1735 module_init(init_btrfs_fs)
1736 module_exit(exit_btrfs_fs)
1737
1738 MODULE_LICENSE("GPL");