forked from torvalds/linux
-
Notifications
You must be signed in to change notification settings - Fork 0
/
Copy pathsuper.c
1427 lines (1263 loc) · 35.9 KB
/
super.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
/*
* Copyright (C) 2007 Oracle. All rights reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License v2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public
* License along with this program; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 021110-1307, USA.
*/
#include <linux/blkdev.h>
#include <linux/module.h>
#include <linux/buffer_head.h>
#include <linux/fs.h>
#include <linux/pagemap.h>
#include <linux/highmem.h>
#include <linux/time.h>
#include <linux/init.h>
#include <linux/seq_file.h>
#include <linux/string.h>
#include <linux/backing-dev.h>
#include <linux/mount.h>
#include <linux/mpage.h>
#include <linux/swap.h>
#include <linux/writeback.h>
#include <linux/statfs.h>
#include <linux/compat.h>
#include <linux/parser.h>
#include <linux/ctype.h>
#include <linux/namei.h>
#include <linux/miscdevice.h>
#include <linux/magic.h>
#include <linux/slab.h>
#include <linux/cleancache.h>
#include <linux/ratelimit.h>
#include "compat.h"
#include "delayed-inode.h"
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
#include "btrfs_inode.h"
#include "ioctl.h"
#include "print-tree.h"
#include "xattr.h"
#include "volumes.h"
#include "version.h"
#include "export.h"
#include "compression.h"
#define CREATE_TRACE_POINTS
#include <trace/events/btrfs.h>
static const struct super_operations btrfs_super_ops;
static struct file_system_type btrfs_fs_type;
static const char *btrfs_decode_error(struct btrfs_fs_info *fs_info, int errno,
char nbuf[16])
{
char *errstr = NULL;
switch (errno) {
case -EIO:
errstr = "IO failure";
break;
case -ENOMEM:
errstr = "Out of memory";
break;
case -EROFS:
errstr = "Readonly filesystem";
break;
default:
if (nbuf) {
if (snprintf(nbuf, 16, "error %d", -errno) >= 0)
errstr = nbuf;
}
break;
}
return errstr;
}
static void __save_error_info(struct btrfs_fs_info *fs_info)
{
/*
* today we only save the error info into ram. Long term we'll
* also send it down to the disk
*/
fs_info->fs_state = BTRFS_SUPER_FLAG_ERROR;
}
/* NOTE:
* We move write_super stuff at umount in order to avoid deadlock
* for umount hold all lock.
*/
static void save_error_info(struct btrfs_fs_info *fs_info)
{
__save_error_info(fs_info);
}
/* btrfs handle error by forcing the filesystem readonly */
static void btrfs_handle_error(struct btrfs_fs_info *fs_info)
{
struct super_block *sb = fs_info->sb;
if (sb->s_flags & MS_RDONLY)
return;
if (fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
sb->s_flags |= MS_RDONLY;
printk(KERN_INFO "btrfs is forced readonly\n");
}
}
/*
* __btrfs_std_error decodes expected errors from the caller and
* invokes the approciate error response.
*/
void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function,
unsigned int line, int errno)
{
struct super_block *sb = fs_info->sb;
char nbuf[16];
const char *errstr;
/*
* Special case: if the error is EROFS, and we're already
* under MS_RDONLY, then it is safe here.
*/
if (errno == -EROFS && (sb->s_flags & MS_RDONLY))
return;
errstr = btrfs_decode_error(fs_info, errno, nbuf);
printk(KERN_CRIT "BTRFS error (device %s) in %s:%d: %s\n",
sb->s_id, function, line, errstr);
save_error_info(fs_info);
btrfs_handle_error(fs_info);
}
static void btrfs_put_super(struct super_block *sb)
{
(void)close_ctree(btrfs_sb(sb)->tree_root);
/* FIXME: need to fix VFS to return error? */
/* AV: return it _where_? ->put_super() can be triggered by any number
* of async events, up to and including delivery of SIGKILL to the
* last process that kept it busy. Or segfault in the aforementioned
* process... Whom would you report that to?
*/
}
enum {
Opt_degraded, Opt_subvol, Opt_subvolid, Opt_device, Opt_nodatasum,
Opt_nodatacow, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd,
Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl, Opt_compress,
Opt_compress_type, Opt_compress_force, Opt_compress_force_type,
Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard,
Opt_space_cache, Opt_clear_cache, Opt_user_subvol_rm_allowed,
Opt_enospc_debug, Opt_subvolrootid, Opt_defrag, Opt_inode_cache,
Opt_no_space_cache, Opt_recovery, Opt_skip_balance,
Opt_check_integrity, Opt_check_integrity_including_extent_data,
Opt_check_integrity_print_mask,
Opt_err,
};
static match_table_t tokens = {
{Opt_degraded, "degraded"},
{Opt_subvol, "subvol=%s"},
{Opt_subvolid, "subvolid=%d"},
{Opt_device, "device=%s"},
{Opt_nodatasum, "nodatasum"},
{Opt_nodatacow, "nodatacow"},
{Opt_nobarrier, "nobarrier"},
{Opt_max_inline, "max_inline=%s"},
{Opt_alloc_start, "alloc_start=%s"},
{Opt_thread_pool, "thread_pool=%d"},
{Opt_compress, "compress"},
{Opt_compress_type, "compress=%s"},
{Opt_compress_force, "compress-force"},
{Opt_compress_force_type, "compress-force=%s"},
{Opt_ssd, "ssd"},
{Opt_ssd_spread, "ssd_spread"},
{Opt_nossd, "nossd"},
{Opt_noacl, "noacl"},
{Opt_notreelog, "notreelog"},
{Opt_flushoncommit, "flushoncommit"},
{Opt_ratio, "metadata_ratio=%d"},
{Opt_discard, "discard"},
{Opt_space_cache, "space_cache"},
{Opt_clear_cache, "clear_cache"},
{Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
{Opt_enospc_debug, "enospc_debug"},
{Opt_subvolrootid, "subvolrootid=%d"},
{Opt_defrag, "autodefrag"},
{Opt_inode_cache, "inode_cache"},
{Opt_no_space_cache, "nospace_cache"},
{Opt_recovery, "recovery"},
{Opt_skip_balance, "skip_balance"},
{Opt_check_integrity, "check_int"},
{Opt_check_integrity_including_extent_data, "check_int_data"},
{Opt_check_integrity_print_mask, "check_int_print_mask=%d"},
{Opt_err, NULL},
};
/*
* Regular mount options parser. Everything that is needed only when
* reading in a new superblock is parsed here.
*/
int btrfs_parse_options(struct btrfs_root *root, char *options)
{
struct btrfs_fs_info *info = root->fs_info;
substring_t args[MAX_OPT_ARGS];
char *p, *num, *orig = NULL;
u64 cache_gen;
int intarg;
int ret = 0;
char *compress_type;
bool compress_force = false;
cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
if (cache_gen)
btrfs_set_opt(info->mount_opt, SPACE_CACHE);
if (!options)
goto out;
/*
* strsep changes the string, duplicate it because parse_options
* gets called twice
*/
options = kstrdup(options, GFP_NOFS);
if (!options)
return -ENOMEM;
orig = options;
while ((p = strsep(&options, ",")) != NULL) {
int token;
if (!*p)
continue;
token = match_token(p, tokens, args);
switch (token) {
case Opt_degraded:
printk(KERN_INFO "btrfs: allowing degraded mounts\n");
btrfs_set_opt(info->mount_opt, DEGRADED);
break;
case Opt_subvol:
case Opt_subvolid:
case Opt_subvolrootid:
case Opt_device:
/*
* These are parsed by btrfs_parse_early_options
* and can be happily ignored here.
*/
break;
case Opt_nodatasum:
printk(KERN_INFO "btrfs: setting nodatasum\n");
btrfs_set_opt(info->mount_opt, NODATASUM);
break;
case Opt_nodatacow:
printk(KERN_INFO "btrfs: setting nodatacow\n");
btrfs_set_opt(info->mount_opt, NODATACOW);
btrfs_set_opt(info->mount_opt, NODATASUM);
break;
case Opt_compress_force:
case Opt_compress_force_type:
compress_force = true;
case Opt_compress:
case Opt_compress_type:
if (token == Opt_compress ||
token == Opt_compress_force ||
strcmp(args[0].from, "zlib") == 0) {
compress_type = "zlib";
info->compress_type = BTRFS_COMPRESS_ZLIB;
} else if (strcmp(args[0].from, "lzo") == 0) {
compress_type = "lzo";
info->compress_type = BTRFS_COMPRESS_LZO;
} else {
ret = -EINVAL;
goto out;
}
btrfs_set_opt(info->mount_opt, COMPRESS);
if (compress_force) {
btrfs_set_opt(info->mount_opt, FORCE_COMPRESS);
pr_info("btrfs: force %s compression\n",
compress_type);
} else
pr_info("btrfs: use %s compression\n",
compress_type);
break;
case Opt_ssd:
printk(KERN_INFO "btrfs: use ssd allocation scheme\n");
btrfs_set_opt(info->mount_opt, SSD);
break;
case Opt_ssd_spread:
printk(KERN_INFO "btrfs: use spread ssd "
"allocation scheme\n");
btrfs_set_opt(info->mount_opt, SSD);
btrfs_set_opt(info->mount_opt, SSD_SPREAD);
break;
case Opt_nossd:
printk(KERN_INFO "btrfs: not using ssd allocation "
"scheme\n");
btrfs_set_opt(info->mount_opt, NOSSD);
btrfs_clear_opt(info->mount_opt, SSD);
btrfs_clear_opt(info->mount_opt, SSD_SPREAD);
break;
case Opt_nobarrier:
printk(KERN_INFO "btrfs: turning off barriers\n");
btrfs_set_opt(info->mount_opt, NOBARRIER);
break;
case Opt_thread_pool:
intarg = 0;
match_int(&args[0], &intarg);
if (intarg) {
info->thread_pool_size = intarg;
printk(KERN_INFO "btrfs: thread pool %d\n",
info->thread_pool_size);
}
break;
case Opt_max_inline:
num = match_strdup(&args[0]);
if (num) {
info->max_inline = memparse(num, NULL);
kfree(num);
if (info->max_inline) {
info->max_inline = max_t(u64,
info->max_inline,
root->sectorsize);
}
printk(KERN_INFO "btrfs: max_inline at %llu\n",
(unsigned long long)info->max_inline);
}
break;
case Opt_alloc_start:
num = match_strdup(&args[0]);
if (num) {
info->alloc_start = memparse(num, NULL);
kfree(num);
printk(KERN_INFO
"btrfs: allocations start at %llu\n",
(unsigned long long)info->alloc_start);
}
break;
case Opt_noacl:
root->fs_info->sb->s_flags &= ~MS_POSIXACL;
break;
case Opt_notreelog:
printk(KERN_INFO "btrfs: disabling tree log\n");
btrfs_set_opt(info->mount_opt, NOTREELOG);
break;
case Opt_flushoncommit:
printk(KERN_INFO "btrfs: turning on flush-on-commit\n");
btrfs_set_opt(info->mount_opt, FLUSHONCOMMIT);
break;
case Opt_ratio:
intarg = 0;
match_int(&args[0], &intarg);
if (intarg) {
info->metadata_ratio = intarg;
printk(KERN_INFO "btrfs: metadata ratio %d\n",
info->metadata_ratio);
}
break;
case Opt_discard:
btrfs_set_opt(info->mount_opt, DISCARD);
break;
case Opt_space_cache:
btrfs_set_opt(info->mount_opt, SPACE_CACHE);
break;
case Opt_no_space_cache:
printk(KERN_INFO "btrfs: disabling disk space caching\n");
btrfs_clear_opt(info->mount_opt, SPACE_CACHE);
break;
case Opt_inode_cache:
printk(KERN_INFO "btrfs: enabling inode map caching\n");
btrfs_set_opt(info->mount_opt, INODE_MAP_CACHE);
break;
case Opt_clear_cache:
printk(KERN_INFO "btrfs: force clearing of disk cache\n");
btrfs_set_opt(info->mount_opt, CLEAR_CACHE);
break;
case Opt_user_subvol_rm_allowed:
btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
break;
case Opt_enospc_debug:
btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
break;
case Opt_defrag:
printk(KERN_INFO "btrfs: enabling auto defrag");
btrfs_set_opt(info->mount_opt, AUTO_DEFRAG);
break;
case Opt_recovery:
printk(KERN_INFO "btrfs: enabling auto recovery");
btrfs_set_opt(info->mount_opt, RECOVERY);
break;
case Opt_skip_balance:
btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
break;
#ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
case Opt_check_integrity_including_extent_data:
printk(KERN_INFO "btrfs: enabling check integrity"
" including extent data\n");
btrfs_set_opt(info->mount_opt,
CHECK_INTEGRITY_INCLUDING_EXTENT_DATA);
btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
break;
case Opt_check_integrity:
printk(KERN_INFO "btrfs: enabling check integrity\n");
btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
break;
case Opt_check_integrity_print_mask:
intarg = 0;
match_int(&args[0], &intarg);
if (intarg) {
info->check_integrity_print_mask = intarg;
printk(KERN_INFO "btrfs:"
" check_integrity_print_mask 0x%x\n",
info->check_integrity_print_mask);
}
break;
#else
case Opt_check_integrity_including_extent_data:
case Opt_check_integrity:
case Opt_check_integrity_print_mask:
printk(KERN_ERR "btrfs: support for check_integrity*"
" not compiled in!\n");
ret = -EINVAL;
goto out;
#endif
case Opt_err:
printk(KERN_INFO "btrfs: unrecognized mount option "
"'%s'\n", p);
ret = -EINVAL;
goto out;
default:
break;
}
}
out:
if (!ret && btrfs_test_opt(root, SPACE_CACHE))
printk(KERN_INFO "btrfs: disk space caching is enabled\n");
kfree(orig);
return ret;
}
/*
* Parse mount options that are required early in the mount process.
*
* All other options will be parsed on much later in the mount process and
* only when we need to allocate a new super block.
*/
static int btrfs_parse_early_options(const char *options, fmode_t flags,
void *holder, char **subvol_name, u64 *subvol_objectid,
u64 *subvol_rootid, struct btrfs_fs_devices **fs_devices)
{
substring_t args[MAX_OPT_ARGS];
char *device_name, *opts, *orig, *p;
int error = 0;
int intarg;
if (!options)
return 0;
/*
* strsep changes the string, duplicate it because parse_options
* gets called twice
*/
opts = kstrdup(options, GFP_KERNEL);
if (!opts)
return -ENOMEM;
orig = opts;
while ((p = strsep(&opts, ",")) != NULL) {
int token;
if (!*p)
continue;
token = match_token(p, tokens, args);
switch (token) {
case Opt_subvol:
kfree(*subvol_name);
*subvol_name = match_strdup(&args[0]);
break;
case Opt_subvolid:
intarg = 0;
error = match_int(&args[0], &intarg);
if (!error) {
/* we want the original fs_tree */
if (!intarg)
*subvol_objectid =
BTRFS_FS_TREE_OBJECTID;
else
*subvol_objectid = intarg;
}
break;
case Opt_subvolrootid:
intarg = 0;
error = match_int(&args[0], &intarg);
if (!error) {
/* we want the original fs_tree */
if (!intarg)
*subvol_rootid =
BTRFS_FS_TREE_OBJECTID;
else
*subvol_rootid = intarg;
}
break;
case Opt_device:
device_name = match_strdup(&args[0]);
if (!device_name) {
error = -ENOMEM;
goto out;
}
error = btrfs_scan_one_device(device_name,
flags, holder, fs_devices);
kfree(device_name);
if (error)
goto out;
break;
default:
break;
}
}
out:
kfree(orig);
return error;
}
static struct dentry *get_default_root(struct super_block *sb,
u64 subvol_objectid)
{
struct btrfs_fs_info *fs_info = btrfs_sb(sb);
struct btrfs_root *root = fs_info->tree_root;
struct btrfs_root *new_root;
struct btrfs_dir_item *di;
struct btrfs_path *path;
struct btrfs_key location;
struct inode *inode;
u64 dir_id;
int new = 0;
/*
* We have a specific subvol we want to mount, just setup location and
* go look up the root.
*/
if (subvol_objectid) {
location.objectid = subvol_objectid;
location.type = BTRFS_ROOT_ITEM_KEY;
location.offset = (u64)-1;
goto find_root;
}
path = btrfs_alloc_path();
if (!path)
return ERR_PTR(-ENOMEM);
path->leave_spinning = 1;
/*
* Find the "default" dir item which points to the root item that we
* will mount by default if we haven't been given a specific subvolume
* to mount.
*/
dir_id = btrfs_super_root_dir(fs_info->super_copy);
di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
if (IS_ERR(di)) {
btrfs_free_path(path);
return ERR_CAST(di);
}
if (!di) {
/*
* Ok the default dir item isn't there. This is weird since
* it's always been there, but don't freak out, just try and
* mount to root most subvolume.
*/
btrfs_free_path(path);
dir_id = BTRFS_FIRST_FREE_OBJECTID;
new_root = fs_info->fs_root;
goto setup_root;
}
btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
btrfs_free_path(path);
find_root:
new_root = btrfs_read_fs_root_no_name(fs_info, &location);
if (IS_ERR(new_root))
return ERR_CAST(new_root);
if (btrfs_root_refs(&new_root->root_item) == 0)
return ERR_PTR(-ENOENT);
dir_id = btrfs_root_dirid(&new_root->root_item);
setup_root:
location.objectid = dir_id;
location.type = BTRFS_INODE_ITEM_KEY;
location.offset = 0;
inode = btrfs_iget(sb, &location, new_root, &new);
if (IS_ERR(inode))
return ERR_CAST(inode);
/*
* If we're just mounting the root most subvol put the inode and return
* a reference to the dentry. We will have already gotten a reference
* to the inode in btrfs_fill_super so we're good to go.
*/
if (!new && sb->s_root->d_inode == inode) {
iput(inode);
return dget(sb->s_root);
}
return d_obtain_alias(inode);
}
static int btrfs_fill_super(struct super_block *sb,
struct btrfs_fs_devices *fs_devices,
void *data, int silent)
{
struct inode *inode;
struct dentry *root_dentry;
struct btrfs_fs_info *fs_info = btrfs_sb(sb);
struct btrfs_key key;
int err;
sb->s_maxbytes = MAX_LFS_FILESIZE;
sb->s_magic = BTRFS_SUPER_MAGIC;
sb->s_op = &btrfs_super_ops;
sb->s_d_op = &btrfs_dentry_operations;
sb->s_export_op = &btrfs_export_ops;
sb->s_xattr = btrfs_xattr_handlers;
sb->s_time_gran = 1;
#ifdef CONFIG_BTRFS_FS_POSIX_ACL
sb->s_flags |= MS_POSIXACL;
#endif
err = open_ctree(sb, fs_devices, (char *)data);
if (err) {
printk("btrfs: open_ctree failed\n");
return err;
}
key.objectid = BTRFS_FIRST_FREE_OBJECTID;
key.type = BTRFS_INODE_ITEM_KEY;
key.offset = 0;
inode = btrfs_iget(sb, &key, fs_info->fs_root, NULL);
if (IS_ERR(inode)) {
err = PTR_ERR(inode);
goto fail_close;
}
root_dentry = d_alloc_root(inode);
if (!root_dentry) {
iput(inode);
err = -ENOMEM;
goto fail_close;
}
sb->s_root = root_dentry;
save_mount_options(sb, data);
cleancache_init_fs(sb);
sb->s_flags |= MS_ACTIVE;
return 0;
fail_close:
close_ctree(fs_info->tree_root);
return err;
}
int btrfs_sync_fs(struct super_block *sb, int wait)
{
struct btrfs_trans_handle *trans;
struct btrfs_fs_info *fs_info = btrfs_sb(sb);
struct btrfs_root *root = fs_info->tree_root;
int ret;
trace_btrfs_sync_fs(wait);
if (!wait) {
filemap_flush(fs_info->btree_inode->i_mapping);
return 0;
}
btrfs_start_delalloc_inodes(root, 0);
btrfs_wait_ordered_extents(root, 0, 0);
trans = btrfs_start_transaction(root, 0);
if (IS_ERR(trans))
return PTR_ERR(trans);
ret = btrfs_commit_transaction(trans, root);
return ret;
}
static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
{
struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
struct btrfs_root *root = info->tree_root;
char *compress_type;
if (btrfs_test_opt(root, DEGRADED))
seq_puts(seq, ",degraded");
if (btrfs_test_opt(root, NODATASUM))
seq_puts(seq, ",nodatasum");
if (btrfs_test_opt(root, NODATACOW))
seq_puts(seq, ",nodatacow");
if (btrfs_test_opt(root, NOBARRIER))
seq_puts(seq, ",nobarrier");
if (info->max_inline != 8192 * 1024)
seq_printf(seq, ",max_inline=%llu",
(unsigned long long)info->max_inline);
if (info->alloc_start != 0)
seq_printf(seq, ",alloc_start=%llu",
(unsigned long long)info->alloc_start);
if (info->thread_pool_size != min_t(unsigned long,
num_online_cpus() + 2, 8))
seq_printf(seq, ",thread_pool=%d", info->thread_pool_size);
if (btrfs_test_opt(root, COMPRESS)) {
if (info->compress_type == BTRFS_COMPRESS_ZLIB)
compress_type = "zlib";
else
compress_type = "lzo";
if (btrfs_test_opt(root, FORCE_COMPRESS))
seq_printf(seq, ",compress-force=%s", compress_type);
else
seq_printf(seq, ",compress=%s", compress_type);
}
if (btrfs_test_opt(root, NOSSD))
seq_puts(seq, ",nossd");
if (btrfs_test_opt(root, SSD_SPREAD))
seq_puts(seq, ",ssd_spread");
else if (btrfs_test_opt(root, SSD))
seq_puts(seq, ",ssd");
if (btrfs_test_opt(root, NOTREELOG))
seq_puts(seq, ",notreelog");
if (btrfs_test_opt(root, FLUSHONCOMMIT))
seq_puts(seq, ",flushoncommit");
if (btrfs_test_opt(root, DISCARD))
seq_puts(seq, ",discard");
if (!(root->fs_info->sb->s_flags & MS_POSIXACL))
seq_puts(seq, ",noacl");
if (btrfs_test_opt(root, SPACE_CACHE))
seq_puts(seq, ",space_cache");
else
seq_puts(seq, ",nospace_cache");
if (btrfs_test_opt(root, CLEAR_CACHE))
seq_puts(seq, ",clear_cache");
if (btrfs_test_opt(root, USER_SUBVOL_RM_ALLOWED))
seq_puts(seq, ",user_subvol_rm_allowed");
if (btrfs_test_opt(root, ENOSPC_DEBUG))
seq_puts(seq, ",enospc_debug");
if (btrfs_test_opt(root, AUTO_DEFRAG))
seq_puts(seq, ",autodefrag");
if (btrfs_test_opt(root, INODE_MAP_CACHE))
seq_puts(seq, ",inode_cache");
if (btrfs_test_opt(root, SKIP_BALANCE))
seq_puts(seq, ",skip_balance");
return 0;
}
static int btrfs_test_super(struct super_block *s, void *data)
{
struct btrfs_fs_info *p = data;
struct btrfs_fs_info *fs_info = btrfs_sb(s);
return fs_info->fs_devices == p->fs_devices;
}
static int btrfs_set_super(struct super_block *s, void *data)
{
int err = set_anon_super(s, data);
if (!err)
s->s_fs_info = data;
return err;
}
/*
* subvolumes are identified by ino 256
*/
static inline int is_subvolume_inode(struct inode *inode)
{
if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
return 1;
return 0;
}
/*
* This will strip out the subvol=%s argument for an argument string and add
* subvolid=0 to make sure we get the actual tree root for path walking to the
* subvol we want.
*/
static char *setup_root_args(char *args)
{
unsigned copied = 0;
unsigned len = strlen(args) + 2;
char *pos;
char *ret;
/*
* We need the same args as before, but minus
*
* subvol=a
*
* and add
*
* subvolid=0
*
* which is a difference of 2 characters, so we allocate strlen(args) +
* 2 characters.
*/
ret = kzalloc(len * sizeof(char), GFP_NOFS);
if (!ret)
return NULL;
pos = strstr(args, "subvol=");
/* This shouldn't happen, but just in case.. */
if (!pos) {
kfree(ret);
return NULL;
}
/*
* The subvol=<> arg is not at the front of the string, copy everybody
* up to that into ret.
*/
if (pos != args) {
*pos = '\0';
strcpy(ret, args);
copied += strlen(args);
pos++;
}
strncpy(ret + copied, "subvolid=0", len - copied);
/* Length of subvolid=0 */
copied += 10;
/*
* If there is no , after the subvol= option then we know there's no
* other options and we can just return.
*/
pos = strchr(pos, ',');
if (!pos)
return ret;
/* Copy the rest of the arguments into our buffer */
strncpy(ret + copied, pos, len - copied);
copied += strlen(pos);
return ret;
}
static struct dentry *mount_subvol(const char *subvol_name, int flags,
const char *device_name, char *data)
{
struct dentry *root;
struct vfsmount *mnt;
char *newargs;
newargs = setup_root_args(data);
if (!newargs)
return ERR_PTR(-ENOMEM);
mnt = vfs_kern_mount(&btrfs_fs_type, flags, device_name,
newargs);
kfree(newargs);
if (IS_ERR(mnt))
return ERR_CAST(mnt);
root = mount_subtree(mnt, subvol_name);
if (!IS_ERR(root) && !is_subvolume_inode(root->d_inode)) {
struct super_block *s = root->d_sb;
dput(root);
root = ERR_PTR(-EINVAL);
deactivate_locked_super(s);
printk(KERN_ERR "btrfs: '%s' is not a valid subvolume\n",
subvol_name);
}
return root;
}
/*
* Find a superblock for the given device / mount point.
*
* Note: This is based on get_sb_bdev from fs/super.c with a few additions
* for multiple device setup. Make sure to keep it in sync.
*/
static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
const char *device_name, void *data)
{
struct block_device *bdev = NULL;
struct super_block *s;
struct dentry *root;
struct btrfs_fs_devices *fs_devices = NULL;
struct btrfs_fs_info *fs_info = NULL;
fmode_t mode = FMODE_READ;
char *subvol_name = NULL;
u64 subvol_objectid = 0;
u64 subvol_rootid = 0;
int error = 0;
if (!(flags & MS_RDONLY))
mode |= FMODE_WRITE;
error = btrfs_parse_early_options(data, mode, fs_type,
&subvol_name, &subvol_objectid,
&subvol_rootid, &fs_devices);
if (error) {
kfree(subvol_name);
return ERR_PTR(error);
}
if (subvol_name) {
root = mount_subvol(subvol_name, flags, device_name, data);
kfree(subvol_name);
return root;
}
error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices);
if (error)
return ERR_PTR(error);
/*
* Setup a dummy root and fs_info for test/set super. This is because
* we don't actually fill this stuff out until open_ctree, but we need
* it for searching for existing supers, so this lets us do that and
* then open_ctree will properly initialize everything later.
*/
fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_NOFS);
if (!fs_info)
return ERR_PTR(-ENOMEM);
fs_info->fs_devices = fs_devices;
fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
if (!fs_info->super_copy || !fs_info->super_for_commit) {
error = -ENOMEM;
goto error_fs_info;
}
error = btrfs_open_devices(fs_devices, mode, fs_type);
if (error)
goto error_fs_info;
if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
error = -EACCES;
goto error_close_devices;
}
bdev = fs_devices->latest_bdev;
s = sget(fs_type, btrfs_test_super, btrfs_set_super, fs_info);
if (IS_ERR(s)) {
error = PTR_ERR(s);
goto error_close_devices;
}
if (s->s_root) {
btrfs_close_devices(fs_devices);
free_fs_info(fs_info);
if ((flags ^ s->s_flags) & MS_RDONLY)
error = -EBUSY;
} else {
char b[BDEVNAME_SIZE];
s->s_flags = flags | MS_NOSEC;
strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
btrfs_sb(s)->bdev_holder = fs_type;
error = btrfs_fill_super(s, fs_devices, data,
flags & MS_SILENT ? 1 : 0);
}
root = !error ? get_default_root(s, subvol_objectid) : ERR_PTR(error);
if (IS_ERR(root))
deactivate_locked_super(s);
return root;
error_close_devices:
btrfs_close_devices(fs_devices);
error_fs_info:
free_fs_info(fs_info);
return ERR_PTR(error);
}
static int btrfs_remount(struct super_block *sb, int *flags, char *data)
{
struct btrfs_fs_info *fs_info = btrfs_sb(sb);