btrfs: return original error code when failing from option parsing
[sfrench/cifs-2.6.git] / fs / btrfs / super.c
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2007 Oracle.  All rights reserved.
4  */
5
6 #include <linux/blkdev.h>
7 #include <linux/module.h>
8 #include <linux/buffer_head.h>
9 #include <linux/fs.h>
10 #include <linux/pagemap.h>
11 #include <linux/highmem.h>
12 #include <linux/time.h>
13 #include <linux/init.h>
14 #include <linux/seq_file.h>
15 #include <linux/string.h>
16 #include <linux/backing-dev.h>
17 #include <linux/mount.h>
18 #include <linux/mpage.h>
19 #include <linux/swap.h>
20 #include <linux/writeback.h>
21 #include <linux/statfs.h>
22 #include <linux/compat.h>
23 #include <linux/parser.h>
24 #include <linux/ctype.h>
25 #include <linux/namei.h>
26 #include <linux/miscdevice.h>
27 #include <linux/magic.h>
28 #include <linux/slab.h>
29 #include <linux/cleancache.h>
30 #include <linux/ratelimit.h>
31 #include <linux/crc32c.h>
32 #include <linux/btrfs.h>
33 #include "delayed-inode.h"
34 #include "ctree.h"
35 #include "disk-io.h"
36 #include "transaction.h"
37 #include "btrfs_inode.h"
38 #include "print-tree.h"
39 #include "props.h"
40 #include "xattr.h"
41 #include "volumes.h"
42 #include "export.h"
43 #include "compression.h"
44 #include "rcu-string.h"
45 #include "dev-replace.h"
46 #include "free-space-cache.h"
47 #include "backref.h"
48 #include "tests/btrfs-tests.h"
49
50 #include "qgroup.h"
51 #define CREATE_TRACE_POINTS
52 #include <trace/events/btrfs.h>
53
54 static const struct super_operations btrfs_super_ops;
55
56 /*
57  * Types for mounting the default subvolume and a subvolume explicitly
58  * requested by subvol=/path. That way the callchain is straightforward and we
59  * don't have to play tricks with the mount options and recursive calls to
60  * btrfs_mount.
61  *
62  * The new btrfs_root_fs_type also servers as a tag for the bdev_holder.
63  */
64 static struct file_system_type btrfs_fs_type;
65 static struct file_system_type btrfs_root_fs_type;
66
67 static int btrfs_remount(struct super_block *sb, int *flags, char *data);
68
69 const char *btrfs_decode_error(int errno)
70 {
71         char *errstr = "unknown";
72
73         switch (errno) {
74         case -EIO:
75                 errstr = "IO failure";
76                 break;
77         case -ENOMEM:
78                 errstr = "Out of memory";
79                 break;
80         case -EROFS:
81                 errstr = "Readonly filesystem";
82                 break;
83         case -EEXIST:
84                 errstr = "Object already exists";
85                 break;
86         case -ENOSPC:
87                 errstr = "No space left";
88                 break;
89         case -ENOENT:
90                 errstr = "No such entry";
91                 break;
92         }
93
94         return errstr;
95 }
96
97 /*
98  * __btrfs_handle_fs_error decodes expected errors from the caller and
99  * invokes the approciate error response.
100  */
101 __cold
102 void __btrfs_handle_fs_error(struct btrfs_fs_info *fs_info, const char *function,
103                        unsigned int line, int errno, const char *fmt, ...)
104 {
105         struct super_block *sb = fs_info->sb;
106 #ifdef CONFIG_PRINTK
107         const char *errstr;
108 #endif
109
110         /*
111          * Special case: if the error is EROFS, and we're already
112          * under SB_RDONLY, then it is safe here.
113          */
114         if (errno == -EROFS && sb_rdonly(sb))
115                 return;
116
117 #ifdef CONFIG_PRINTK
118         errstr = btrfs_decode_error(errno);
119         if (fmt) {
120                 struct va_format vaf;
121                 va_list args;
122
123                 va_start(args, fmt);
124                 vaf.fmt = fmt;
125                 vaf.va = &args;
126
127                 pr_crit("BTRFS: error (device %s) in %s:%d: errno=%d %s (%pV)\n",
128                         sb->s_id, function, line, errno, errstr, &vaf);
129                 va_end(args);
130         } else {
131                 pr_crit("BTRFS: error (device %s) in %s:%d: errno=%d %s\n",
132                         sb->s_id, function, line, errno, errstr);
133         }
134 #endif
135
136         /*
137          * Today we only save the error info to memory.  Long term we'll
138          * also send it down to the disk
139          */
140         set_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state);
141
142         /* Don't go through full error handling during mount */
143         if (!(sb->s_flags & SB_BORN))
144                 return;
145
146         if (sb_rdonly(sb))
147                 return;
148
149         /* btrfs handle error by forcing the filesystem readonly */
150         sb->s_flags |= SB_RDONLY;
151         btrfs_info(fs_info, "forced readonly");
152         /*
153          * Note that a running device replace operation is not canceled here
154          * although there is no way to update the progress. It would add the
155          * risk of a deadlock, therefore the canceling is omitted. The only
156          * penalty is that some I/O remains active until the procedure
157          * completes. The next time when the filesystem is mounted writeable
158          * again, the device replace operation continues.
159          */
160 }
161
162 #ifdef CONFIG_PRINTK
163 static const char * const logtypes[] = {
164         "emergency",
165         "alert",
166         "critical",
167         "error",
168         "warning",
169         "notice",
170         "info",
171         "debug",
172 };
173
174
175 /*
176  * Use one ratelimit state per log level so that a flood of less important
177  * messages doesn't cause more important ones to be dropped.
178  */
179 static struct ratelimit_state printk_limits[] = {
180         RATELIMIT_STATE_INIT(printk_limits[0], DEFAULT_RATELIMIT_INTERVAL, 100),
181         RATELIMIT_STATE_INIT(printk_limits[1], DEFAULT_RATELIMIT_INTERVAL, 100),
182         RATELIMIT_STATE_INIT(printk_limits[2], DEFAULT_RATELIMIT_INTERVAL, 100),
183         RATELIMIT_STATE_INIT(printk_limits[3], DEFAULT_RATELIMIT_INTERVAL, 100),
184         RATELIMIT_STATE_INIT(printk_limits[4], DEFAULT_RATELIMIT_INTERVAL, 100),
185         RATELIMIT_STATE_INIT(printk_limits[5], DEFAULT_RATELIMIT_INTERVAL, 100),
186         RATELIMIT_STATE_INIT(printk_limits[6], DEFAULT_RATELIMIT_INTERVAL, 100),
187         RATELIMIT_STATE_INIT(printk_limits[7], DEFAULT_RATELIMIT_INTERVAL, 100),
188 };
189
190 void btrfs_printk(const struct btrfs_fs_info *fs_info, const char *fmt, ...)
191 {
192         char lvl[PRINTK_MAX_SINGLE_HEADER_LEN + 1] = "\0";
193         struct va_format vaf;
194         va_list args;
195         int kern_level;
196         const char *type = logtypes[4];
197         struct ratelimit_state *ratelimit = &printk_limits[4];
198
199         va_start(args, fmt);
200
201         while ((kern_level = printk_get_level(fmt)) != 0) {
202                 size_t size = printk_skip_level(fmt) - fmt;
203
204                 if (kern_level >= '0' && kern_level <= '7') {
205                         memcpy(lvl, fmt,  size);
206                         lvl[size] = '\0';
207                         type = logtypes[kern_level - '0'];
208                         ratelimit = &printk_limits[kern_level - '0'];
209                 }
210                 fmt += size;
211         }
212
213         vaf.fmt = fmt;
214         vaf.va = &args;
215
216         if (__ratelimit(ratelimit))
217                 printk("%sBTRFS %s (device %s): %pV\n", lvl, type,
218                         fs_info ? fs_info->sb->s_id : "<unknown>", &vaf);
219
220         va_end(args);
221 }
222 #endif
223
224 /*
225  * We only mark the transaction aborted and then set the file system read-only.
226  * This will prevent new transactions from starting or trying to join this
227  * one.
228  *
229  * This means that error recovery at the call site is limited to freeing
230  * any local memory allocations and passing the error code up without
231  * further cleanup. The transaction should complete as it normally would
232  * in the call path but will return -EIO.
233  *
234  * We'll complete the cleanup in btrfs_end_transaction and
235  * btrfs_commit_transaction.
236  */
237 __cold
238 void __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
239                                const char *function,
240                                unsigned int line, int errno)
241 {
242         struct btrfs_fs_info *fs_info = trans->fs_info;
243
244         trans->aborted = errno;
245         /* Nothing used. The other threads that have joined this
246          * transaction may be able to continue. */
247         if (!trans->dirty && list_empty(&trans->new_bgs)) {
248                 const char *errstr;
249
250                 errstr = btrfs_decode_error(errno);
251                 btrfs_warn(fs_info,
252                            "%s:%d: Aborting unused transaction(%s).",
253                            function, line, errstr);
254                 return;
255         }
256         WRITE_ONCE(trans->transaction->aborted, errno);
257         /* Wake up anybody who may be waiting on this transaction */
258         wake_up(&fs_info->transaction_wait);
259         wake_up(&fs_info->transaction_blocked_wait);
260         __btrfs_handle_fs_error(fs_info, function, line, errno, NULL);
261 }
262 /*
263  * __btrfs_panic decodes unexpected, fatal errors from the caller,
264  * issues an alert, and either panics or BUGs, depending on mount options.
265  */
266 __cold
267 void __btrfs_panic(struct btrfs_fs_info *fs_info, const char *function,
268                    unsigned int line, int errno, const char *fmt, ...)
269 {
270         char *s_id = "<unknown>";
271         const char *errstr;
272         struct va_format vaf = { .fmt = fmt };
273         va_list args;
274
275         if (fs_info)
276                 s_id = fs_info->sb->s_id;
277
278         va_start(args, fmt);
279         vaf.va = &args;
280
281         errstr = btrfs_decode_error(errno);
282         if (fs_info && (btrfs_test_opt(fs_info, PANIC_ON_FATAL_ERROR)))
283                 panic(KERN_CRIT "BTRFS panic (device %s) in %s:%d: %pV (errno=%d %s)\n",
284                         s_id, function, line, &vaf, errno, errstr);
285
286         btrfs_crit(fs_info, "panic in %s:%d: %pV (errno=%d %s)",
287                    function, line, &vaf, errno, errstr);
288         va_end(args);
289         /* Caller calls BUG() */
290 }
291
292 static void btrfs_put_super(struct super_block *sb)
293 {
294         close_ctree(btrfs_sb(sb));
295 }
296
297 enum {
298         Opt_acl, Opt_noacl,
299         Opt_clear_cache,
300         Opt_commit_interval,
301         Opt_compress,
302         Opt_compress_force,
303         Opt_compress_force_type,
304         Opt_compress_type,
305         Opt_degraded,
306         Opt_device,
307         Opt_fatal_errors,
308         Opt_flushoncommit, Opt_noflushoncommit,
309         Opt_inode_cache, Opt_noinode_cache,
310         Opt_max_inline,
311         Opt_barrier, Opt_nobarrier,
312         Opt_datacow, Opt_nodatacow,
313         Opt_datasum, Opt_nodatasum,
314         Opt_defrag, Opt_nodefrag,
315         Opt_discard, Opt_nodiscard,
316         Opt_nologreplay,
317         Opt_norecovery,
318         Opt_ratio,
319         Opt_rescan_uuid_tree,
320         Opt_skip_balance,
321         Opt_space_cache, Opt_no_space_cache,
322         Opt_space_cache_version,
323         Opt_ssd, Opt_nossd,
324         Opt_ssd_spread, Opt_nossd_spread,
325         Opt_subvol,
326         Opt_subvolid,
327         Opt_thread_pool,
328         Opt_treelog, Opt_notreelog,
329         Opt_usebackuproot,
330         Opt_user_subvol_rm_allowed,
331
332         /* Deprecated options */
333         Opt_alloc_start,
334         Opt_recovery,
335         Opt_subvolrootid,
336
337         /* Debugging options */
338         Opt_check_integrity,
339         Opt_check_integrity_including_extent_data,
340         Opt_check_integrity_print_mask,
341         Opt_enospc_debug, Opt_noenospc_debug,
342 #ifdef CONFIG_BTRFS_DEBUG
343         Opt_fragment_data, Opt_fragment_metadata, Opt_fragment_all,
344 #endif
345 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
346         Opt_ref_verify,
347 #endif
348         Opt_err,
349 };
350
351 static const match_table_t tokens = {
352         {Opt_acl, "acl"},
353         {Opt_noacl, "noacl"},
354         {Opt_clear_cache, "clear_cache"},
355         {Opt_commit_interval, "commit=%u"},
356         {Opt_compress, "compress"},
357         {Opt_compress_type, "compress=%s"},
358         {Opt_compress_force, "compress-force"},
359         {Opt_compress_force_type, "compress-force=%s"},
360         {Opt_degraded, "degraded"},
361         {Opt_device, "device=%s"},
362         {Opt_fatal_errors, "fatal_errors=%s"},
363         {Opt_flushoncommit, "flushoncommit"},
364         {Opt_noflushoncommit, "noflushoncommit"},
365         {Opt_inode_cache, "inode_cache"},
366         {Opt_noinode_cache, "noinode_cache"},
367         {Opt_max_inline, "max_inline=%s"},
368         {Opt_barrier, "barrier"},
369         {Opt_nobarrier, "nobarrier"},
370         {Opt_datacow, "datacow"},
371         {Opt_nodatacow, "nodatacow"},
372         {Opt_datasum, "datasum"},
373         {Opt_nodatasum, "nodatasum"},
374         {Opt_defrag, "autodefrag"},
375         {Opt_nodefrag, "noautodefrag"},
376         {Opt_discard, "discard"},
377         {Opt_nodiscard, "nodiscard"},
378         {Opt_nologreplay, "nologreplay"},
379         {Opt_norecovery, "norecovery"},
380         {Opt_ratio, "metadata_ratio=%u"},
381         {Opt_rescan_uuid_tree, "rescan_uuid_tree"},
382         {Opt_skip_balance, "skip_balance"},
383         {Opt_space_cache, "space_cache"},
384         {Opt_no_space_cache, "nospace_cache"},
385         {Opt_space_cache_version, "space_cache=%s"},
386         {Opt_ssd, "ssd"},
387         {Opt_nossd, "nossd"},
388         {Opt_ssd_spread, "ssd_spread"},
389         {Opt_nossd_spread, "nossd_spread"},
390         {Opt_subvol, "subvol=%s"},
391         {Opt_subvolid, "subvolid=%s"},
392         {Opt_thread_pool, "thread_pool=%u"},
393         {Opt_treelog, "treelog"},
394         {Opt_notreelog, "notreelog"},
395         {Opt_usebackuproot, "usebackuproot"},
396         {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
397
398         /* Deprecated options */
399         {Opt_alloc_start, "alloc_start=%s"},
400         {Opt_recovery, "recovery"},
401         {Opt_subvolrootid, "subvolrootid=%d"},
402
403         /* Debugging options */
404         {Opt_check_integrity, "check_int"},
405         {Opt_check_integrity_including_extent_data, "check_int_data"},
406         {Opt_check_integrity_print_mask, "check_int_print_mask=%u"},
407         {Opt_enospc_debug, "enospc_debug"},
408         {Opt_noenospc_debug, "noenospc_debug"},
409 #ifdef CONFIG_BTRFS_DEBUG
410         {Opt_fragment_data, "fragment=data"},
411         {Opt_fragment_metadata, "fragment=metadata"},
412         {Opt_fragment_all, "fragment=all"},
413 #endif
414 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
415         {Opt_ref_verify, "ref_verify"},
416 #endif
417         {Opt_err, NULL},
418 };
419
420 /*
421  * Regular mount options parser.  Everything that is needed only when
422  * reading in a new superblock is parsed here.
423  * XXX JDM: This needs to be cleaned up for remount.
424  */
425 int btrfs_parse_options(struct btrfs_fs_info *info, char *options,
426                         unsigned long new_flags)
427 {
428         substring_t args[MAX_OPT_ARGS];
429         char *p, *num;
430         u64 cache_gen;
431         int intarg;
432         int ret = 0;
433         char *compress_type;
434         bool compress_force = false;
435         enum btrfs_compression_type saved_compress_type;
436         bool saved_compress_force;
437         int no_compress = 0;
438
439         cache_gen = btrfs_super_cache_generation(info->super_copy);
440         if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE))
441                 btrfs_set_opt(info->mount_opt, FREE_SPACE_TREE);
442         else if (cache_gen)
443                 btrfs_set_opt(info->mount_opt, SPACE_CACHE);
444
445         /*
446          * Even the options are empty, we still need to do extra check
447          * against new flags
448          */
449         if (!options)
450                 goto check;
451
452         while ((p = strsep(&options, ",")) != NULL) {
453                 int token;
454                 if (!*p)
455                         continue;
456
457                 token = match_token(p, tokens, args);
458                 switch (token) {
459                 case Opt_degraded:
460                         btrfs_info(info, "allowing degraded mounts");
461                         btrfs_set_opt(info->mount_opt, DEGRADED);
462                         break;
463                 case Opt_subvol:
464                 case Opt_subvolid:
465                 case Opt_subvolrootid:
466                 case Opt_device:
467                         /*
468                          * These are parsed by btrfs_parse_subvol_options
469                          * and btrfs_parse_early_options
470                          * and can be happily ignored here.
471                          */
472                         break;
473                 case Opt_nodatasum:
474                         btrfs_set_and_info(info, NODATASUM,
475                                            "setting nodatasum");
476                         break;
477                 case Opt_datasum:
478                         if (btrfs_test_opt(info, NODATASUM)) {
479                                 if (btrfs_test_opt(info, NODATACOW))
480                                         btrfs_info(info,
481                                                    "setting datasum, datacow enabled");
482                                 else
483                                         btrfs_info(info, "setting datasum");
484                         }
485                         btrfs_clear_opt(info->mount_opt, NODATACOW);
486                         btrfs_clear_opt(info->mount_opt, NODATASUM);
487                         break;
488                 case Opt_nodatacow:
489                         if (!btrfs_test_opt(info, NODATACOW)) {
490                                 if (!btrfs_test_opt(info, COMPRESS) ||
491                                     !btrfs_test_opt(info, FORCE_COMPRESS)) {
492                                         btrfs_info(info,
493                                                    "setting nodatacow, compression disabled");
494                                 } else {
495                                         btrfs_info(info, "setting nodatacow");
496                                 }
497                         }
498                         btrfs_clear_opt(info->mount_opt, COMPRESS);
499                         btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
500                         btrfs_set_opt(info->mount_opt, NODATACOW);
501                         btrfs_set_opt(info->mount_opt, NODATASUM);
502                         break;
503                 case Opt_datacow:
504                         btrfs_clear_and_info(info, NODATACOW,
505                                              "setting datacow");
506                         break;
507                 case Opt_compress_force:
508                 case Opt_compress_force_type:
509                         compress_force = true;
510                         /* Fallthrough */
511                 case Opt_compress:
512                 case Opt_compress_type:
513                         saved_compress_type = btrfs_test_opt(info,
514                                                              COMPRESS) ?
515                                 info->compress_type : BTRFS_COMPRESS_NONE;
516                         saved_compress_force =
517                                 btrfs_test_opt(info, FORCE_COMPRESS);
518                         if (token == Opt_compress ||
519                             token == Opt_compress_force ||
520                             strncmp(args[0].from, "zlib", 4) == 0) {
521                                 compress_type = "zlib";
522
523                                 info->compress_type = BTRFS_COMPRESS_ZLIB;
524                                 info->compress_level = BTRFS_ZLIB_DEFAULT_LEVEL;
525                                 /*
526                                  * args[0] contains uninitialized data since
527                                  * for these tokens we don't expect any
528                                  * parameter.
529                                  */
530                                 if (token != Opt_compress &&
531                                     token != Opt_compress_force)
532                                         info->compress_level =
533                                           btrfs_compress_str2level(args[0].from);
534                                 btrfs_set_opt(info->mount_opt, COMPRESS);
535                                 btrfs_clear_opt(info->mount_opt, NODATACOW);
536                                 btrfs_clear_opt(info->mount_opt, NODATASUM);
537                                 no_compress = 0;
538                         } else if (strncmp(args[0].from, "lzo", 3) == 0) {
539                                 compress_type = "lzo";
540                                 info->compress_type = BTRFS_COMPRESS_LZO;
541                                 btrfs_set_opt(info->mount_opt, COMPRESS);
542                                 btrfs_clear_opt(info->mount_opt, NODATACOW);
543                                 btrfs_clear_opt(info->mount_opt, NODATASUM);
544                                 btrfs_set_fs_incompat(info, COMPRESS_LZO);
545                                 no_compress = 0;
546                         } else if (strcmp(args[0].from, "zstd") == 0) {
547                                 compress_type = "zstd";
548                                 info->compress_type = BTRFS_COMPRESS_ZSTD;
549                                 btrfs_set_opt(info->mount_opt, COMPRESS);
550                                 btrfs_clear_opt(info->mount_opt, NODATACOW);
551                                 btrfs_clear_opt(info->mount_opt, NODATASUM);
552                                 btrfs_set_fs_incompat(info, COMPRESS_ZSTD);
553                                 no_compress = 0;
554                         } else if (strncmp(args[0].from, "no", 2) == 0) {
555                                 compress_type = "no";
556                                 btrfs_clear_opt(info->mount_opt, COMPRESS);
557                                 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
558                                 compress_force = false;
559                                 no_compress++;
560                         } else {
561                                 ret = -EINVAL;
562                                 goto out;
563                         }
564
565                         if (compress_force) {
566                                 btrfs_set_opt(info->mount_opt, FORCE_COMPRESS);
567                         } else {
568                                 /*
569                                  * If we remount from compress-force=xxx to
570                                  * compress=xxx, we need clear FORCE_COMPRESS
571                                  * flag, otherwise, there is no way for users
572                                  * to disable forcible compression separately.
573                                  */
574                                 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
575                         }
576                         if ((btrfs_test_opt(info, COMPRESS) &&
577                              (info->compress_type != saved_compress_type ||
578                               compress_force != saved_compress_force)) ||
579                             (!btrfs_test_opt(info, COMPRESS) &&
580                              no_compress == 1)) {
581                                 btrfs_info(info, "%s %s compression, level %d",
582                                            (compress_force) ? "force" : "use",
583                                            compress_type, info->compress_level);
584                         }
585                         compress_force = false;
586                         break;
587                 case Opt_ssd:
588                         btrfs_set_and_info(info, SSD,
589                                            "enabling ssd optimizations");
590                         btrfs_clear_opt(info->mount_opt, NOSSD);
591                         break;
592                 case Opt_ssd_spread:
593                         btrfs_set_and_info(info, SSD,
594                                            "enabling ssd optimizations");
595                         btrfs_set_and_info(info, SSD_SPREAD,
596                                            "using spread ssd allocation scheme");
597                         btrfs_clear_opt(info->mount_opt, NOSSD);
598                         break;
599                 case Opt_nossd:
600                         btrfs_set_opt(info->mount_opt, NOSSD);
601                         btrfs_clear_and_info(info, SSD,
602                                              "not using ssd optimizations");
603                         /* Fallthrough */
604                 case Opt_nossd_spread:
605                         btrfs_clear_and_info(info, SSD_SPREAD,
606                                              "not using spread ssd allocation scheme");
607                         break;
608                 case Opt_barrier:
609                         btrfs_clear_and_info(info, NOBARRIER,
610                                              "turning on barriers");
611                         break;
612                 case Opt_nobarrier:
613                         btrfs_set_and_info(info, NOBARRIER,
614                                            "turning off barriers");
615                         break;
616                 case Opt_thread_pool:
617                         ret = match_int(&args[0], &intarg);
618                         if (ret) {
619                                 goto out;
620                         } else if (intarg == 0) {
621                                 ret = -EINVAL;
622                                 goto out;
623                         }
624                         info->thread_pool_size = intarg;
625                         break;
626                 case Opt_max_inline:
627                         num = match_strdup(&args[0]);
628                         if (num) {
629                                 info->max_inline = memparse(num, NULL);
630                                 kfree(num);
631
632                                 if (info->max_inline) {
633                                         info->max_inline = min_t(u64,
634                                                 info->max_inline,
635                                                 info->sectorsize);
636                                 }
637                                 btrfs_info(info, "max_inline at %llu",
638                                            info->max_inline);
639                         } else {
640                                 ret = -ENOMEM;
641                                 goto out;
642                         }
643                         break;
644                 case Opt_alloc_start:
645                         btrfs_info(info,
646                                 "option alloc_start is obsolete, ignored");
647                         break;
648                 case Opt_acl:
649 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
650                         info->sb->s_flags |= SB_POSIXACL;
651                         break;
652 #else
653                         btrfs_err(info, "support for ACL not compiled in!");
654                         ret = -EINVAL;
655                         goto out;
656 #endif
657                 case Opt_noacl:
658                         info->sb->s_flags &= ~SB_POSIXACL;
659                         break;
660                 case Opt_notreelog:
661                         btrfs_set_and_info(info, NOTREELOG,
662                                            "disabling tree log");
663                         break;
664                 case Opt_treelog:
665                         btrfs_clear_and_info(info, NOTREELOG,
666                                              "enabling tree log");
667                         break;
668                 case Opt_norecovery:
669                 case Opt_nologreplay:
670                         btrfs_set_and_info(info, NOLOGREPLAY,
671                                            "disabling log replay at mount time");
672                         break;
673                 case Opt_flushoncommit:
674                         btrfs_set_and_info(info, FLUSHONCOMMIT,
675                                            "turning on flush-on-commit");
676                         break;
677                 case Opt_noflushoncommit:
678                         btrfs_clear_and_info(info, FLUSHONCOMMIT,
679                                              "turning off flush-on-commit");
680                         break;
681                 case Opt_ratio:
682                         ret = match_int(&args[0], &intarg);
683                         if (ret)
684                                 goto out;
685                         info->metadata_ratio = intarg;
686                         btrfs_info(info, "metadata ratio %u",
687                                    info->metadata_ratio);
688                         break;
689                 case Opt_discard:
690                         btrfs_set_and_info(info, DISCARD,
691                                            "turning on discard");
692                         break;
693                 case Opt_nodiscard:
694                         btrfs_clear_and_info(info, DISCARD,
695                                              "turning off discard");
696                         break;
697                 case Opt_space_cache:
698                 case Opt_space_cache_version:
699                         if (token == Opt_space_cache ||
700                             strcmp(args[0].from, "v1") == 0) {
701                                 btrfs_clear_opt(info->mount_opt,
702                                                 FREE_SPACE_TREE);
703                                 btrfs_set_and_info(info, SPACE_CACHE,
704                                            "enabling disk space caching");
705                         } else if (strcmp(args[0].from, "v2") == 0) {
706                                 btrfs_clear_opt(info->mount_opt,
707                                                 SPACE_CACHE);
708                                 btrfs_set_and_info(info, FREE_SPACE_TREE,
709                                                    "enabling free space tree");
710                         } else {
711                                 ret = -EINVAL;
712                                 goto out;
713                         }
714                         break;
715                 case Opt_rescan_uuid_tree:
716                         btrfs_set_opt(info->mount_opt, RESCAN_UUID_TREE);
717                         break;
718                 case Opt_no_space_cache:
719                         if (btrfs_test_opt(info, SPACE_CACHE)) {
720                                 btrfs_clear_and_info(info, SPACE_CACHE,
721                                              "disabling disk space caching");
722                         }
723                         if (btrfs_test_opt(info, FREE_SPACE_TREE)) {
724                                 btrfs_clear_and_info(info, FREE_SPACE_TREE,
725                                              "disabling free space tree");
726                         }
727                         break;
728                 case Opt_inode_cache:
729                         btrfs_set_pending_and_info(info, INODE_MAP_CACHE,
730                                            "enabling inode map caching");
731                         break;
732                 case Opt_noinode_cache:
733                         btrfs_clear_pending_and_info(info, INODE_MAP_CACHE,
734                                              "disabling inode map caching");
735                         break;
736                 case Opt_clear_cache:
737                         btrfs_set_and_info(info, CLEAR_CACHE,
738                                            "force clearing of disk cache");
739                         break;
740                 case Opt_user_subvol_rm_allowed:
741                         btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
742                         break;
743                 case Opt_enospc_debug:
744                         btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
745                         break;
746                 case Opt_noenospc_debug:
747                         btrfs_clear_opt(info->mount_opt, ENOSPC_DEBUG);
748                         break;
749                 case Opt_defrag:
750                         btrfs_set_and_info(info, AUTO_DEFRAG,
751                                            "enabling auto defrag");
752                         break;
753                 case Opt_nodefrag:
754                         btrfs_clear_and_info(info, AUTO_DEFRAG,
755                                              "disabling auto defrag");
756                         break;
757                 case Opt_recovery:
758                         btrfs_warn(info,
759                                    "'recovery' is deprecated, use 'usebackuproot' instead");
760                 case Opt_usebackuproot:
761                         btrfs_info(info,
762                                    "trying to use backup root at mount time");
763                         btrfs_set_opt(info->mount_opt, USEBACKUPROOT);
764                         break;
765                 case Opt_skip_balance:
766                         btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
767                         break;
768 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
769                 case Opt_check_integrity_including_extent_data:
770                         btrfs_info(info,
771                                    "enabling check integrity including extent data");
772                         btrfs_set_opt(info->mount_opt,
773                                       CHECK_INTEGRITY_INCLUDING_EXTENT_DATA);
774                         btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
775                         break;
776                 case Opt_check_integrity:
777                         btrfs_info(info, "enabling check integrity");
778                         btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
779                         break;
780                 case Opt_check_integrity_print_mask:
781                         ret = match_int(&args[0], &intarg);
782                         if (ret)
783                                 goto out;
784                         info->check_integrity_print_mask = intarg;
785                         btrfs_info(info, "check_integrity_print_mask 0x%x",
786                                    info->check_integrity_print_mask);
787                         break;
788 #else
789                 case Opt_check_integrity_including_extent_data:
790                 case Opt_check_integrity:
791                 case Opt_check_integrity_print_mask:
792                         btrfs_err(info,
793                                   "support for check_integrity* not compiled in!");
794                         ret = -EINVAL;
795                         goto out;
796 #endif
797                 case Opt_fatal_errors:
798                         if (strcmp(args[0].from, "panic") == 0)
799                                 btrfs_set_opt(info->mount_opt,
800                                               PANIC_ON_FATAL_ERROR);
801                         else if (strcmp(args[0].from, "bug") == 0)
802                                 btrfs_clear_opt(info->mount_opt,
803                                               PANIC_ON_FATAL_ERROR);
804                         else {
805                                 ret = -EINVAL;
806                                 goto out;
807                         }
808                         break;
809                 case Opt_commit_interval:
810                         intarg = 0;
811                         ret = match_int(&args[0], &intarg);
812                         if (ret)
813                                 goto out;
814                         if (intarg == 0) {
815                                 btrfs_info(info,
816                                            "using default commit interval %us",
817                                            BTRFS_DEFAULT_COMMIT_INTERVAL);
818                                 intarg = BTRFS_DEFAULT_COMMIT_INTERVAL;
819                         } else if (intarg > 300) {
820                                 btrfs_warn(info, "excessive commit interval %d",
821                                            intarg);
822                         }
823                         info->commit_interval = intarg;
824                         break;
825 #ifdef CONFIG_BTRFS_DEBUG
826                 case Opt_fragment_all:
827                         btrfs_info(info, "fragmenting all space");
828                         btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
829                         btrfs_set_opt(info->mount_opt, FRAGMENT_METADATA);
830                         break;
831                 case Opt_fragment_metadata:
832                         btrfs_info(info, "fragmenting metadata");
833                         btrfs_set_opt(info->mount_opt,
834                                       FRAGMENT_METADATA);
835                         break;
836                 case Opt_fragment_data:
837                         btrfs_info(info, "fragmenting data");
838                         btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
839                         break;
840 #endif
841 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
842                 case Opt_ref_verify:
843                         btrfs_info(info, "doing ref verification");
844                         btrfs_set_opt(info->mount_opt, REF_VERIFY);
845                         break;
846 #endif
847                 case Opt_err:
848                         btrfs_info(info, "unrecognized mount option '%s'", p);
849                         ret = -EINVAL;
850                         goto out;
851                 default:
852                         break;
853                 }
854         }
855 check:
856         /*
857          * Extra check for current option against current flag
858          */
859         if (btrfs_test_opt(info, NOLOGREPLAY) && !(new_flags & SB_RDONLY)) {
860                 btrfs_err(info,
861                           "nologreplay must be used with ro mount option");
862                 ret = -EINVAL;
863         }
864 out:
865         if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE) &&
866             !btrfs_test_opt(info, FREE_SPACE_TREE) &&
867             !btrfs_test_opt(info, CLEAR_CACHE)) {
868                 btrfs_err(info, "cannot disable free space tree");
869                 ret = -EINVAL;
870
871         }
872         if (!ret && btrfs_test_opt(info, SPACE_CACHE))
873                 btrfs_info(info, "disk space caching is enabled");
874         if (!ret && btrfs_test_opt(info, FREE_SPACE_TREE))
875                 btrfs_info(info, "using free space tree");
876         return ret;
877 }
878
879 /*
880  * Parse mount options that are required early in the mount process.
881  *
882  * All other options will be parsed on much later in the mount process and
883  * only when we need to allocate a new super block.
884  */
885 static int btrfs_parse_early_options(const char *options, fmode_t flags,
886                 void *holder, struct btrfs_fs_devices **fs_devices)
887 {
888         substring_t args[MAX_OPT_ARGS];
889         char *device_name, *opts, *orig, *p;
890         int error = 0;
891
892         if (!options)
893                 return 0;
894
895         /*
896          * strsep changes the string, duplicate it because btrfs_parse_options
897          * gets called later
898          */
899         opts = kstrdup(options, GFP_KERNEL);
900         if (!opts)
901                 return -ENOMEM;
902         orig = opts;
903
904         while ((p = strsep(&opts, ",")) != NULL) {
905                 int token;
906
907                 if (!*p)
908                         continue;
909
910                 token = match_token(p, tokens, args);
911                 if (token == Opt_device) {
912                         device_name = match_strdup(&args[0]);
913                         if (!device_name) {
914                                 error = -ENOMEM;
915                                 goto out;
916                         }
917                         error = btrfs_scan_one_device(device_name,
918                                         flags, holder, fs_devices);
919                         kfree(device_name);
920                         if (error)
921                                 goto out;
922                 }
923         }
924
925 out:
926         kfree(orig);
927         return error;
928 }
929
930 /*
931  * Parse mount options that are related to subvolume id
932  *
933  * The value is later passed to mount_subvol()
934  */
935 static int btrfs_parse_subvol_options(const char *options, fmode_t flags,
936                 char **subvol_name, u64 *subvol_objectid)
937 {
938         substring_t args[MAX_OPT_ARGS];
939         char *opts, *orig, *p;
940         int error = 0;
941         u64 subvolid;
942
943         if (!options)
944                 return 0;
945
946         /*
947          * strsep changes the string, duplicate it because
948          * btrfs_parse_early_options gets called later
949          */
950         opts = kstrdup(options, GFP_KERNEL);
951         if (!opts)
952                 return -ENOMEM;
953         orig = opts;
954
955         while ((p = strsep(&opts, ",")) != NULL) {
956                 int token;
957                 if (!*p)
958                         continue;
959
960                 token = match_token(p, tokens, args);
961                 switch (token) {
962                 case Opt_subvol:
963                         kfree(*subvol_name);
964                         *subvol_name = match_strdup(&args[0]);
965                         if (!*subvol_name) {
966                                 error = -ENOMEM;
967                                 goto out;
968                         }
969                         break;
970                 case Opt_subvolid:
971                         error = match_u64(&args[0], &subvolid);
972                         if (error)
973                                 goto out;
974
975                         /* we want the original fs_tree */
976                         if (subvolid == 0)
977                                 subvolid = BTRFS_FS_TREE_OBJECTID;
978
979                         *subvol_objectid = subvolid;
980                         break;
981                 case Opt_subvolrootid:
982                         pr_warn("BTRFS: 'subvolrootid' mount option is deprecated and has no effect\n");
983                         break;
984                 default:
985                         break;
986                 }
987         }
988
989 out:
990         kfree(orig);
991         return error;
992 }
993
994 static char *get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
995                                            u64 subvol_objectid)
996 {
997         struct btrfs_root *root = fs_info->tree_root;
998         struct btrfs_root *fs_root;
999         struct btrfs_root_ref *root_ref;
1000         struct btrfs_inode_ref *inode_ref;
1001         struct btrfs_key key;
1002         struct btrfs_path *path = NULL;
1003         char *name = NULL, *ptr;
1004         u64 dirid;
1005         int len;
1006         int ret;
1007
1008         path = btrfs_alloc_path();
1009         if (!path) {
1010                 ret = -ENOMEM;
1011                 goto err;
1012         }
1013         path->leave_spinning = 1;
1014
1015         name = kmalloc(PATH_MAX, GFP_KERNEL);
1016         if (!name) {
1017                 ret = -ENOMEM;
1018                 goto err;
1019         }
1020         ptr = name + PATH_MAX - 1;
1021         ptr[0] = '\0';
1022
1023         /*
1024          * Walk up the subvolume trees in the tree of tree roots by root
1025          * backrefs until we hit the top-level subvolume.
1026          */
1027         while (subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
1028                 key.objectid = subvol_objectid;
1029                 key.type = BTRFS_ROOT_BACKREF_KEY;
1030                 key.offset = (u64)-1;
1031
1032                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1033                 if (ret < 0) {
1034                         goto err;
1035                 } else if (ret > 0) {
1036                         ret = btrfs_previous_item(root, path, subvol_objectid,
1037                                                   BTRFS_ROOT_BACKREF_KEY);
1038                         if (ret < 0) {
1039                                 goto err;
1040                         } else if (ret > 0) {
1041                                 ret = -ENOENT;
1042                                 goto err;
1043                         }
1044                 }
1045
1046                 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1047                 subvol_objectid = key.offset;
1048
1049                 root_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
1050                                           struct btrfs_root_ref);
1051                 len = btrfs_root_ref_name_len(path->nodes[0], root_ref);
1052                 ptr -= len + 1;
1053                 if (ptr < name) {
1054                         ret = -ENAMETOOLONG;
1055                         goto err;
1056                 }
1057                 read_extent_buffer(path->nodes[0], ptr + 1,
1058                                    (unsigned long)(root_ref + 1), len);
1059                 ptr[0] = '/';
1060                 dirid = btrfs_root_ref_dirid(path->nodes[0], root_ref);
1061                 btrfs_release_path(path);
1062
1063                 key.objectid = subvol_objectid;
1064                 key.type = BTRFS_ROOT_ITEM_KEY;
1065                 key.offset = (u64)-1;
1066                 fs_root = btrfs_read_fs_root_no_name(fs_info, &key);
1067                 if (IS_ERR(fs_root)) {
1068                         ret = PTR_ERR(fs_root);
1069                         goto err;
1070                 }
1071
1072                 /*
1073                  * Walk up the filesystem tree by inode refs until we hit the
1074                  * root directory.
1075                  */
1076                 while (dirid != BTRFS_FIRST_FREE_OBJECTID) {
1077                         key.objectid = dirid;
1078                         key.type = BTRFS_INODE_REF_KEY;
1079                         key.offset = (u64)-1;
1080
1081                         ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0);
1082                         if (ret < 0) {
1083                                 goto err;
1084                         } else if (ret > 0) {
1085                                 ret = btrfs_previous_item(fs_root, path, dirid,
1086                                                           BTRFS_INODE_REF_KEY);
1087                                 if (ret < 0) {
1088                                         goto err;
1089                                 } else if (ret > 0) {
1090                                         ret = -ENOENT;
1091                                         goto err;
1092                                 }
1093                         }
1094
1095                         btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1096                         dirid = key.offset;
1097
1098                         inode_ref = btrfs_item_ptr(path->nodes[0],
1099                                                    path->slots[0],
1100                                                    struct btrfs_inode_ref);
1101                         len = btrfs_inode_ref_name_len(path->nodes[0],
1102                                                        inode_ref);
1103                         ptr -= len + 1;
1104                         if (ptr < name) {
1105                                 ret = -ENAMETOOLONG;
1106                                 goto err;
1107                         }
1108                         read_extent_buffer(path->nodes[0], ptr + 1,
1109                                            (unsigned long)(inode_ref + 1), len);
1110                         ptr[0] = '/';
1111                         btrfs_release_path(path);
1112                 }
1113         }
1114
1115         btrfs_free_path(path);
1116         if (ptr == name + PATH_MAX - 1) {
1117                 name[0] = '/';
1118                 name[1] = '\0';
1119         } else {
1120                 memmove(name, ptr, name + PATH_MAX - ptr);
1121         }
1122         return name;
1123
1124 err:
1125         btrfs_free_path(path);
1126         kfree(name);
1127         return ERR_PTR(ret);
1128 }
1129
1130 static int get_default_subvol_objectid(struct btrfs_fs_info *fs_info, u64 *objectid)
1131 {
1132         struct btrfs_root *root = fs_info->tree_root;
1133         struct btrfs_dir_item *di;
1134         struct btrfs_path *path;
1135         struct btrfs_key location;
1136         u64 dir_id;
1137
1138         path = btrfs_alloc_path();
1139         if (!path)
1140                 return -ENOMEM;
1141         path->leave_spinning = 1;
1142
1143         /*
1144          * Find the "default" dir item which points to the root item that we
1145          * will mount by default if we haven't been given a specific subvolume
1146          * to mount.
1147          */
1148         dir_id = btrfs_super_root_dir(fs_info->super_copy);
1149         di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
1150         if (IS_ERR(di)) {
1151                 btrfs_free_path(path);
1152                 return PTR_ERR(di);
1153         }
1154         if (!di) {
1155                 /*
1156                  * Ok the default dir item isn't there.  This is weird since
1157                  * it's always been there, but don't freak out, just try and
1158                  * mount the top-level subvolume.
1159                  */
1160                 btrfs_free_path(path);
1161                 *objectid = BTRFS_FS_TREE_OBJECTID;
1162                 return 0;
1163         }
1164
1165         btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
1166         btrfs_free_path(path);
1167         *objectid = location.objectid;
1168         return 0;
1169 }
1170
1171 static int btrfs_fill_super(struct super_block *sb,
1172                             struct btrfs_fs_devices *fs_devices,
1173                             void *data)
1174 {
1175         struct inode *inode;
1176         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1177         struct btrfs_key key;
1178         int err;
1179
1180         sb->s_maxbytes = MAX_LFS_FILESIZE;
1181         sb->s_magic = BTRFS_SUPER_MAGIC;
1182         sb->s_op = &btrfs_super_ops;
1183         sb->s_d_op = &btrfs_dentry_operations;
1184         sb->s_export_op = &btrfs_export_ops;
1185         sb->s_xattr = btrfs_xattr_handlers;
1186         sb->s_time_gran = 1;
1187 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
1188         sb->s_flags |= SB_POSIXACL;
1189 #endif
1190         sb->s_flags |= SB_I_VERSION;
1191         sb->s_iflags |= SB_I_CGROUPWB;
1192
1193         err = super_setup_bdi(sb);
1194         if (err) {
1195                 btrfs_err(fs_info, "super_setup_bdi failed");
1196                 return err;
1197         }
1198
1199         err = open_ctree(sb, fs_devices, (char *)data);
1200         if (err) {
1201                 btrfs_err(fs_info, "open_ctree failed");
1202                 return err;
1203         }
1204
1205         key.objectid = BTRFS_FIRST_FREE_OBJECTID;
1206         key.type = BTRFS_INODE_ITEM_KEY;
1207         key.offset = 0;
1208         inode = btrfs_iget(sb, &key, fs_info->fs_root, NULL);
1209         if (IS_ERR(inode)) {
1210                 err = PTR_ERR(inode);
1211                 goto fail_close;
1212         }
1213
1214         sb->s_root = d_make_root(inode);
1215         if (!sb->s_root) {
1216                 err = -ENOMEM;
1217                 goto fail_close;
1218         }
1219
1220         cleancache_init_fs(sb);
1221         sb->s_flags |= SB_ACTIVE;
1222         return 0;
1223
1224 fail_close:
1225         close_ctree(fs_info);
1226         return err;
1227 }
1228
1229 int btrfs_sync_fs(struct super_block *sb, int wait)
1230 {
1231         struct btrfs_trans_handle *trans;
1232         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1233         struct btrfs_root *root = fs_info->tree_root;
1234
1235         trace_btrfs_sync_fs(fs_info, wait);
1236
1237         if (!wait) {
1238                 filemap_flush(fs_info->btree_inode->i_mapping);
1239                 return 0;
1240         }
1241
1242         btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
1243
1244         trans = btrfs_attach_transaction_barrier(root);
1245         if (IS_ERR(trans)) {
1246                 /* no transaction, don't bother */
1247                 if (PTR_ERR(trans) == -ENOENT) {
1248                         /*
1249                          * Exit unless we have some pending changes
1250                          * that need to go through commit
1251                          */
1252                         if (fs_info->pending_changes == 0)
1253                                 return 0;
1254                         /*
1255                          * A non-blocking test if the fs is frozen. We must not
1256                          * start a new transaction here otherwise a deadlock
1257                          * happens. The pending operations are delayed to the
1258                          * next commit after thawing.
1259                          */
1260                         if (sb_start_write_trylock(sb))
1261                                 sb_end_write(sb);
1262                         else
1263                                 return 0;
1264                         trans = btrfs_start_transaction(root, 0);
1265                 }
1266                 if (IS_ERR(trans))
1267                         return PTR_ERR(trans);
1268         }
1269         return btrfs_commit_transaction(trans);
1270 }
1271
1272 static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
1273 {
1274         struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
1275         const char *compress_type;
1276
1277         if (btrfs_test_opt(info, DEGRADED))
1278                 seq_puts(seq, ",degraded");
1279         if (btrfs_test_opt(info, NODATASUM))
1280                 seq_puts(seq, ",nodatasum");
1281         if (btrfs_test_opt(info, NODATACOW))
1282                 seq_puts(seq, ",nodatacow");
1283         if (btrfs_test_opt(info, NOBARRIER))
1284                 seq_puts(seq, ",nobarrier");
1285         if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE)
1286                 seq_printf(seq, ",max_inline=%llu", info->max_inline);
1287         if (info->thread_pool_size !=  min_t(unsigned long,
1288                                              num_online_cpus() + 2, 8))
1289                 seq_printf(seq, ",thread_pool=%u", info->thread_pool_size);
1290         if (btrfs_test_opt(info, COMPRESS)) {
1291                 compress_type = btrfs_compress_type2str(info->compress_type);
1292                 if (btrfs_test_opt(info, FORCE_COMPRESS))
1293                         seq_printf(seq, ",compress-force=%s", compress_type);
1294                 else
1295                         seq_printf(seq, ",compress=%s", compress_type);
1296                 if (info->compress_level)
1297                         seq_printf(seq, ":%d", info->compress_level);
1298         }
1299         if (btrfs_test_opt(info, NOSSD))
1300                 seq_puts(seq, ",nossd");
1301         if (btrfs_test_opt(info, SSD_SPREAD))
1302                 seq_puts(seq, ",ssd_spread");
1303         else if (btrfs_test_opt(info, SSD))
1304                 seq_puts(seq, ",ssd");
1305         if (btrfs_test_opt(info, NOTREELOG))
1306                 seq_puts(seq, ",notreelog");
1307         if (btrfs_test_opt(info, NOLOGREPLAY))
1308                 seq_puts(seq, ",nologreplay");
1309         if (btrfs_test_opt(info, FLUSHONCOMMIT))
1310                 seq_puts(seq, ",flushoncommit");
1311         if (btrfs_test_opt(info, DISCARD))
1312                 seq_puts(seq, ",discard");
1313         if (!(info->sb->s_flags & SB_POSIXACL))
1314                 seq_puts(seq, ",noacl");
1315         if (btrfs_test_opt(info, SPACE_CACHE))
1316                 seq_puts(seq, ",space_cache");
1317         else if (btrfs_test_opt(info, FREE_SPACE_TREE))
1318                 seq_puts(seq, ",space_cache=v2");
1319         else
1320                 seq_puts(seq, ",nospace_cache");
1321         if (btrfs_test_opt(info, RESCAN_UUID_TREE))
1322                 seq_puts(seq, ",rescan_uuid_tree");
1323         if (btrfs_test_opt(info, CLEAR_CACHE))
1324                 seq_puts(seq, ",clear_cache");
1325         if (btrfs_test_opt(info, USER_SUBVOL_RM_ALLOWED))
1326                 seq_puts(seq, ",user_subvol_rm_allowed");
1327         if (btrfs_test_opt(info, ENOSPC_DEBUG))
1328                 seq_puts(seq, ",enospc_debug");
1329         if (btrfs_test_opt(info, AUTO_DEFRAG))
1330                 seq_puts(seq, ",autodefrag");
1331         if (btrfs_test_opt(info, INODE_MAP_CACHE))
1332                 seq_puts(seq, ",inode_cache");
1333         if (btrfs_test_opt(info, SKIP_BALANCE))
1334                 seq_puts(seq, ",skip_balance");
1335 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
1336         if (btrfs_test_opt(info, CHECK_INTEGRITY_INCLUDING_EXTENT_DATA))
1337                 seq_puts(seq, ",check_int_data");
1338         else if (btrfs_test_opt(info, CHECK_INTEGRITY))
1339                 seq_puts(seq, ",check_int");
1340         if (info->check_integrity_print_mask)
1341                 seq_printf(seq, ",check_int_print_mask=%d",
1342                                 info->check_integrity_print_mask);
1343 #endif
1344         if (info->metadata_ratio)
1345                 seq_printf(seq, ",metadata_ratio=%u", info->metadata_ratio);
1346         if (btrfs_test_opt(info, PANIC_ON_FATAL_ERROR))
1347                 seq_puts(seq, ",fatal_errors=panic");
1348         if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL)
1349                 seq_printf(seq, ",commit=%u", info->commit_interval);
1350 #ifdef CONFIG_BTRFS_DEBUG
1351         if (btrfs_test_opt(info, FRAGMENT_DATA))
1352                 seq_puts(seq, ",fragment=data");
1353         if (btrfs_test_opt(info, FRAGMENT_METADATA))
1354                 seq_puts(seq, ",fragment=metadata");
1355 #endif
1356         if (btrfs_test_opt(info, REF_VERIFY))
1357                 seq_puts(seq, ",ref_verify");
1358         seq_printf(seq, ",subvolid=%llu",
1359                   BTRFS_I(d_inode(dentry))->root->root_key.objectid);
1360         seq_puts(seq, ",subvol=");
1361         seq_dentry(seq, dentry, " \t\n\\");
1362         return 0;
1363 }
1364
1365 static int btrfs_test_super(struct super_block *s, void *data)
1366 {
1367         struct btrfs_fs_info *p = data;
1368         struct btrfs_fs_info *fs_info = btrfs_sb(s);
1369
1370         return fs_info->fs_devices == p->fs_devices;
1371 }
1372
1373 static int btrfs_set_super(struct super_block *s, void *data)
1374 {
1375         int err = set_anon_super(s, data);
1376         if (!err)
1377                 s->s_fs_info = data;
1378         return err;
1379 }
1380
1381 /*
1382  * subvolumes are identified by ino 256
1383  */
1384 static inline int is_subvolume_inode(struct inode *inode)
1385 {
1386         if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
1387                 return 1;
1388         return 0;
1389 }
1390
1391 static struct dentry *mount_subvol(const char *subvol_name, u64 subvol_objectid,
1392                                    const char *device_name, struct vfsmount *mnt)
1393 {
1394         struct dentry *root;
1395         int ret;
1396
1397         if (!subvol_name) {
1398                 if (!subvol_objectid) {
1399                         ret = get_default_subvol_objectid(btrfs_sb(mnt->mnt_sb),
1400                                                           &subvol_objectid);
1401                         if (ret) {
1402                                 root = ERR_PTR(ret);
1403                                 goto out;
1404                         }
1405                 }
1406                 subvol_name = get_subvol_name_from_objectid(btrfs_sb(mnt->mnt_sb),
1407                                                             subvol_objectid);
1408                 if (IS_ERR(subvol_name)) {
1409                         root = ERR_CAST(subvol_name);
1410                         subvol_name = NULL;
1411                         goto out;
1412                 }
1413
1414         }
1415
1416         root = mount_subtree(mnt, subvol_name);
1417         /* mount_subtree() drops our reference on the vfsmount. */
1418         mnt = NULL;
1419
1420         if (!IS_ERR(root)) {
1421                 struct super_block *s = root->d_sb;
1422                 struct btrfs_fs_info *fs_info = btrfs_sb(s);
1423                 struct inode *root_inode = d_inode(root);
1424                 u64 root_objectid = BTRFS_I(root_inode)->root->root_key.objectid;
1425
1426                 ret = 0;
1427                 if (!is_subvolume_inode(root_inode)) {
1428                         btrfs_err(fs_info, "'%s' is not a valid subvolume",
1429                                subvol_name);
1430                         ret = -EINVAL;
1431                 }
1432                 if (subvol_objectid && root_objectid != subvol_objectid) {
1433                         /*
1434                          * This will also catch a race condition where a
1435                          * subvolume which was passed by ID is renamed and
1436                          * another subvolume is renamed over the old location.
1437                          */
1438                         btrfs_err(fs_info,
1439                                   "subvol '%s' does not match subvolid %llu",
1440                                   subvol_name, subvol_objectid);
1441                         ret = -EINVAL;
1442                 }
1443                 if (ret) {
1444                         dput(root);
1445                         root = ERR_PTR(ret);
1446                         deactivate_locked_super(s);
1447                 }
1448         }
1449
1450 out:
1451         mntput(mnt);
1452         kfree(subvol_name);
1453         return root;
1454 }
1455
1456 static int parse_security_options(char *orig_opts,
1457                                   struct security_mnt_opts *sec_opts)
1458 {
1459         char *secdata = NULL;
1460         int ret = 0;
1461
1462         secdata = alloc_secdata();
1463         if (!secdata)
1464                 return -ENOMEM;
1465         ret = security_sb_copy_data(orig_opts, secdata);
1466         if (ret) {
1467                 free_secdata(secdata);
1468                 return ret;
1469         }
1470         ret = security_sb_parse_opts_str(secdata, sec_opts);
1471         free_secdata(secdata);
1472         return ret;
1473 }
1474
1475 static int setup_security_options(struct btrfs_fs_info *fs_info,
1476                                   struct super_block *sb,
1477                                   struct security_mnt_opts *sec_opts)
1478 {
1479         int ret = 0;
1480
1481         /*
1482          * Call security_sb_set_mnt_opts() to check whether new sec_opts
1483          * is valid.
1484          */
1485         ret = security_sb_set_mnt_opts(sb, sec_opts, 0, NULL);
1486         if (ret)
1487                 return ret;
1488
1489 #ifdef CONFIG_SECURITY
1490         if (!fs_info->security_opts.num_mnt_opts) {
1491                 /* first time security setup, copy sec_opts to fs_info */
1492                 memcpy(&fs_info->security_opts, sec_opts, sizeof(*sec_opts));
1493         } else {
1494                 /*
1495                  * Since SELinux (the only one supporting security_mnt_opts)
1496                  * does NOT support changing context during remount/mount of
1497                  * the same sb, this must be the same or part of the same
1498                  * security options, just free it.
1499                  */
1500                 security_free_mnt_opts(sec_opts);
1501         }
1502 #endif
1503         return ret;
1504 }
1505
1506 /*
1507  * Find a superblock for the given device / mount point.
1508  *
1509  * Note: This is based on mount_bdev from fs/super.c with a few additions
1510  *       for multiple device setup.  Make sure to keep it in sync.
1511  */
1512 static struct dentry *btrfs_mount_root(struct file_system_type *fs_type,
1513                 int flags, const char *device_name, void *data)
1514 {
1515         struct block_device *bdev = NULL;
1516         struct super_block *s;
1517         struct btrfs_fs_devices *fs_devices = NULL;
1518         struct btrfs_fs_info *fs_info = NULL;
1519         struct security_mnt_opts new_sec_opts;
1520         fmode_t mode = FMODE_READ;
1521         int error = 0;
1522
1523         if (!(flags & SB_RDONLY))
1524                 mode |= FMODE_WRITE;
1525
1526         error = btrfs_parse_early_options(data, mode, fs_type,
1527                                           &fs_devices);
1528         if (error) {
1529                 return ERR_PTR(error);
1530         }
1531
1532         security_init_mnt_opts(&new_sec_opts);
1533         if (data) {
1534                 error = parse_security_options(data, &new_sec_opts);
1535                 if (error)
1536                         return ERR_PTR(error);
1537         }
1538
1539         error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices);
1540         if (error)
1541                 goto error_sec_opts;
1542
1543         /*
1544          * Setup a dummy root and fs_info for test/set super.  This is because
1545          * we don't actually fill this stuff out until open_ctree, but we need
1546          * it for searching for existing supers, so this lets us do that and
1547          * then open_ctree will properly initialize everything later.
1548          */
1549         fs_info = kvzalloc(sizeof(struct btrfs_fs_info), GFP_KERNEL);
1550         if (!fs_info) {
1551                 error = -ENOMEM;
1552                 goto error_sec_opts;
1553         }
1554
1555         fs_info->fs_devices = fs_devices;
1556
1557         fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
1558         fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
1559         security_init_mnt_opts(&fs_info->security_opts);
1560         if (!fs_info->super_copy || !fs_info->super_for_commit) {
1561                 error = -ENOMEM;
1562                 goto error_fs_info;
1563         }
1564
1565         error = btrfs_open_devices(fs_devices, mode, fs_type);
1566         if (error)
1567                 goto error_fs_info;
1568
1569         if (!(flags & SB_RDONLY) && fs_devices->rw_devices == 0) {
1570                 error = -EACCES;
1571                 goto error_close_devices;
1572         }
1573
1574         bdev = fs_devices->latest_bdev;
1575         s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | SB_NOSEC,
1576                  fs_info);
1577         if (IS_ERR(s)) {
1578                 error = PTR_ERR(s);
1579                 goto error_close_devices;
1580         }
1581
1582         if (s->s_root) {
1583                 btrfs_close_devices(fs_devices);
1584                 free_fs_info(fs_info);
1585                 if ((flags ^ s->s_flags) & SB_RDONLY)
1586                         error = -EBUSY;
1587         } else {
1588                 snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev);
1589                 btrfs_sb(s)->bdev_holder = fs_type;
1590                 error = btrfs_fill_super(s, fs_devices, data);
1591         }
1592         if (error) {
1593                 deactivate_locked_super(s);
1594                 goto error_sec_opts;
1595         }
1596
1597         fs_info = btrfs_sb(s);
1598         error = setup_security_options(fs_info, s, &new_sec_opts);
1599         if (error) {
1600                 deactivate_locked_super(s);
1601                 goto error_sec_opts;
1602         }
1603
1604         return dget(s->s_root);
1605
1606 error_close_devices:
1607         btrfs_close_devices(fs_devices);
1608 error_fs_info:
1609         free_fs_info(fs_info);
1610 error_sec_opts:
1611         security_free_mnt_opts(&new_sec_opts);
1612         return ERR_PTR(error);
1613 }
1614
1615 /*
1616  * Mount function which is called by VFS layer.
1617  *
1618  * In order to allow mounting a subvolume directly, btrfs uses mount_subtree()
1619  * which needs vfsmount* of device's root (/).  This means device's root has to
1620  * be mounted internally in any case.
1621  *
1622  * Operation flow:
1623  *   1. Parse subvol id related options for later use in mount_subvol().
1624  *
1625  *   2. Mount device's root (/) by calling vfs_kern_mount().
1626  *
1627  *      NOTE: vfs_kern_mount() is used by VFS to call btrfs_mount() in the
1628  *      first place. In order to avoid calling btrfs_mount() again, we use
1629  *      different file_system_type which is not registered to VFS by
1630  *      register_filesystem() (btrfs_root_fs_type). As a result,
1631  *      btrfs_mount_root() is called. The return value will be used by
1632  *      mount_subtree() in mount_subvol().
1633  *
1634  *   3. Call mount_subvol() to get the dentry of subvolume. Since there is
1635  *      "btrfs subvolume set-default", mount_subvol() is called always.
1636  */
1637 static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
1638                 const char *device_name, void *data)
1639 {
1640         struct vfsmount *mnt_root;
1641         struct dentry *root;
1642         fmode_t mode = FMODE_READ;
1643         char *subvol_name = NULL;
1644         u64 subvol_objectid = 0;
1645         int error = 0;
1646
1647         if (!(flags & SB_RDONLY))
1648                 mode |= FMODE_WRITE;
1649
1650         error = btrfs_parse_subvol_options(data, mode,
1651                                           &subvol_name, &subvol_objectid);
1652         if (error) {
1653                 kfree(subvol_name);
1654                 return ERR_PTR(error);
1655         }
1656
1657         /* mount device's root (/) */
1658         mnt_root = vfs_kern_mount(&btrfs_root_fs_type, flags, device_name, data);
1659         if (PTR_ERR_OR_ZERO(mnt_root) == -EBUSY) {
1660                 if (flags & SB_RDONLY) {
1661                         mnt_root = vfs_kern_mount(&btrfs_root_fs_type,
1662                                 flags & ~SB_RDONLY, device_name, data);
1663                 } else {
1664                         mnt_root = vfs_kern_mount(&btrfs_root_fs_type,
1665                                 flags | SB_RDONLY, device_name, data);
1666                         if (IS_ERR(mnt_root)) {
1667                                 root = ERR_CAST(mnt_root);
1668                                 goto out;
1669                         }
1670
1671                         down_write(&mnt_root->mnt_sb->s_umount);
1672                         error = btrfs_remount(mnt_root->mnt_sb, &flags, NULL);
1673                         up_write(&mnt_root->mnt_sb->s_umount);
1674                         if (error < 0) {
1675                                 root = ERR_PTR(error);
1676                                 mntput(mnt_root);
1677                                 goto out;
1678                         }
1679                 }
1680         }
1681         if (IS_ERR(mnt_root)) {
1682                 root = ERR_CAST(mnt_root);
1683                 goto out;
1684         }
1685
1686         /* mount_subvol() will free subvol_name and mnt_root */
1687         root = mount_subvol(subvol_name, subvol_objectid, device_name, mnt_root);
1688
1689 out:
1690         return root;
1691 }
1692
1693 static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
1694                                      u32 new_pool_size, u32 old_pool_size)
1695 {
1696         if (new_pool_size == old_pool_size)
1697                 return;
1698
1699         fs_info->thread_pool_size = new_pool_size;
1700
1701         btrfs_info(fs_info, "resize thread pool %d -> %d",
1702                old_pool_size, new_pool_size);
1703
1704         btrfs_workqueue_set_max(fs_info->workers, new_pool_size);
1705         btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size);
1706         btrfs_workqueue_set_max(fs_info->submit_workers, new_pool_size);
1707         btrfs_workqueue_set_max(fs_info->caching_workers, new_pool_size);
1708         btrfs_workqueue_set_max(fs_info->endio_workers, new_pool_size);
1709         btrfs_workqueue_set_max(fs_info->endio_meta_workers, new_pool_size);
1710         btrfs_workqueue_set_max(fs_info->endio_meta_write_workers,
1711                                 new_pool_size);
1712         btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size);
1713         btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
1714         btrfs_workqueue_set_max(fs_info->delayed_workers, new_pool_size);
1715         btrfs_workqueue_set_max(fs_info->readahead_workers, new_pool_size);
1716         btrfs_workqueue_set_max(fs_info->scrub_wr_completion_workers,
1717                                 new_pool_size);
1718 }
1719
1720 static inline void btrfs_remount_prepare(struct btrfs_fs_info *fs_info)
1721 {
1722         set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1723 }
1724
1725 static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info,
1726                                        unsigned long old_opts, int flags)
1727 {
1728         if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1729             (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1730              (flags & SB_RDONLY))) {
1731                 /* wait for any defraggers to finish */
1732                 wait_event(fs_info->transaction_wait,
1733                            (atomic_read(&fs_info->defrag_running) == 0));
1734                 if (flags & SB_RDONLY)
1735                         sync_filesystem(fs_info->sb);
1736         }
1737 }
1738
1739 static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
1740                                          unsigned long old_opts)
1741 {
1742         /*
1743          * We need to cleanup all defragable inodes if the autodefragment is
1744          * close or the filesystem is read only.
1745          */
1746         if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1747             (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) || sb_rdonly(fs_info->sb))) {
1748                 btrfs_cleanup_defrag_inodes(fs_info);
1749         }
1750
1751         clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1752 }
1753
1754 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
1755 {
1756         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1757         struct btrfs_root *root = fs_info->tree_root;
1758         unsigned old_flags = sb->s_flags;
1759         unsigned long old_opts = fs_info->mount_opt;
1760         unsigned long old_compress_type = fs_info->compress_type;
1761         u64 old_max_inline = fs_info->max_inline;
1762         u32 old_thread_pool_size = fs_info->thread_pool_size;
1763         u32 old_metadata_ratio = fs_info->metadata_ratio;
1764         int ret;
1765
1766         sync_filesystem(sb);
1767         btrfs_remount_prepare(fs_info);
1768
1769         if (data) {
1770                 struct security_mnt_opts new_sec_opts;
1771
1772                 security_init_mnt_opts(&new_sec_opts);
1773                 ret = parse_security_options(data, &new_sec_opts);
1774                 if (ret)
1775                         goto restore;
1776                 ret = setup_security_options(fs_info, sb,
1777                                              &new_sec_opts);
1778                 if (ret) {
1779                         security_free_mnt_opts(&new_sec_opts);
1780                         goto restore;
1781                 }
1782         }
1783
1784         ret = btrfs_parse_options(fs_info, data, *flags);
1785         if (ret)
1786                 goto restore;
1787
1788         btrfs_remount_begin(fs_info, old_opts, *flags);
1789         btrfs_resize_thread_pool(fs_info,
1790                 fs_info->thread_pool_size, old_thread_pool_size);
1791
1792         if ((bool)(*flags & SB_RDONLY) == sb_rdonly(sb))
1793                 goto out;
1794
1795         if (*flags & SB_RDONLY) {
1796                 /*
1797                  * this also happens on 'umount -rf' or on shutdown, when
1798                  * the filesystem is busy.
1799                  */
1800                 cancel_work_sync(&fs_info->async_reclaim_work);
1801
1802                 /* wait for the uuid_scan task to finish */
1803                 down(&fs_info->uuid_tree_rescan_sem);
1804                 /* avoid complains from lockdep et al. */
1805                 up(&fs_info->uuid_tree_rescan_sem);
1806
1807                 sb->s_flags |= SB_RDONLY;
1808
1809                 /*
1810                  * Setting SB_RDONLY will put the cleaner thread to
1811                  * sleep at the next loop if it's already active.
1812                  * If it's already asleep, we'll leave unused block
1813                  * groups on disk until we're mounted read-write again
1814                  * unless we clean them up here.
1815                  */
1816                 btrfs_delete_unused_bgs(fs_info);
1817
1818                 btrfs_dev_replace_suspend_for_unmount(fs_info);
1819                 btrfs_scrub_cancel(fs_info);
1820                 btrfs_pause_balance(fs_info);
1821
1822                 ret = btrfs_commit_super(fs_info);
1823                 if (ret)
1824                         goto restore;
1825         } else {
1826                 if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
1827                         btrfs_err(fs_info,
1828                                 "Remounting read-write after error is not allowed");
1829                         ret = -EINVAL;
1830                         goto restore;
1831                 }
1832                 if (fs_info->fs_devices->rw_devices == 0) {
1833                         ret = -EACCES;
1834                         goto restore;
1835                 }
1836
1837                 if (!btrfs_check_rw_degradable(fs_info, NULL)) {
1838                         btrfs_warn(fs_info,
1839                                 "too many missing devices, writeable remount is not allowed");
1840                         ret = -EACCES;
1841                         goto restore;
1842                 }
1843
1844                 if (btrfs_super_log_root(fs_info->super_copy) != 0) {
1845                         ret = -EINVAL;
1846                         goto restore;
1847                 }
1848
1849                 ret = btrfs_cleanup_fs_roots(fs_info);
1850                 if (ret)
1851                         goto restore;
1852
1853                 /* recover relocation */
1854                 mutex_lock(&fs_info->cleaner_mutex);
1855                 ret = btrfs_recover_relocation(root);
1856                 mutex_unlock(&fs_info->cleaner_mutex);
1857                 if (ret)
1858                         goto restore;
1859
1860                 ret = btrfs_resume_balance_async(fs_info);
1861                 if (ret)
1862                         goto restore;
1863
1864                 ret = btrfs_resume_dev_replace_async(fs_info);
1865                 if (ret) {
1866                         btrfs_warn(fs_info, "failed to resume dev_replace");
1867                         goto restore;
1868                 }
1869
1870                 btrfs_qgroup_rescan_resume(fs_info);
1871
1872                 if (!fs_info->uuid_root) {
1873                         btrfs_info(fs_info, "creating UUID tree");
1874                         ret = btrfs_create_uuid_tree(fs_info);
1875                         if (ret) {
1876                                 btrfs_warn(fs_info,
1877                                            "failed to create the UUID tree %d",
1878                                            ret);
1879                                 goto restore;
1880                         }
1881                 }
1882                 sb->s_flags &= ~SB_RDONLY;
1883
1884                 set_bit(BTRFS_FS_OPEN, &fs_info->flags);
1885         }
1886 out:
1887         wake_up_process(fs_info->transaction_kthread);
1888         btrfs_remount_cleanup(fs_info, old_opts);
1889         return 0;
1890
1891 restore:
1892         /* We've hit an error - don't reset SB_RDONLY */
1893         if (sb_rdonly(sb))
1894                 old_flags |= SB_RDONLY;
1895         sb->s_flags = old_flags;
1896         fs_info->mount_opt = old_opts;
1897         fs_info->compress_type = old_compress_type;
1898         fs_info->max_inline = old_max_inline;
1899         btrfs_resize_thread_pool(fs_info,
1900                 old_thread_pool_size, fs_info->thread_pool_size);
1901         fs_info->metadata_ratio = old_metadata_ratio;
1902         btrfs_remount_cleanup(fs_info, old_opts);
1903         return ret;
1904 }
1905
1906 /* Used to sort the devices by max_avail(descending sort) */
1907 static int btrfs_cmp_device_free_bytes(const void *dev_info1,
1908                                        const void *dev_info2)
1909 {
1910         if (((struct btrfs_device_info *)dev_info1)->max_avail >
1911             ((struct btrfs_device_info *)dev_info2)->max_avail)
1912                 return -1;
1913         else if (((struct btrfs_device_info *)dev_info1)->max_avail <
1914                  ((struct btrfs_device_info *)dev_info2)->max_avail)
1915                 return 1;
1916         else
1917         return 0;
1918 }
1919
1920 /*
1921  * sort the devices by max_avail, in which max free extent size of each device
1922  * is stored.(Descending Sort)
1923  */
1924 static inline void btrfs_descending_sort_devices(
1925                                         struct btrfs_device_info *devices,
1926                                         size_t nr_devices)
1927 {
1928         sort(devices, nr_devices, sizeof(struct btrfs_device_info),
1929              btrfs_cmp_device_free_bytes, NULL);
1930 }
1931
1932 /*
1933  * The helper to calc the free space on the devices that can be used to store
1934  * file data.
1935  */
1936 static int btrfs_calc_avail_data_space(struct btrfs_fs_info *fs_info,
1937                                        u64 *free_bytes)
1938 {
1939         struct btrfs_device_info *devices_info;
1940         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
1941         struct btrfs_device *device;
1942         u64 skip_space;
1943         u64 type;
1944         u64 avail_space;
1945         u64 min_stripe_size;
1946         int min_stripes = 1, num_stripes = 1;
1947         int i = 0, nr_devices;
1948
1949         /*
1950          * We aren't under the device list lock, so this is racy-ish, but good
1951          * enough for our purposes.
1952          */
1953         nr_devices = fs_info->fs_devices->open_devices;
1954         if (!nr_devices) {
1955                 smp_mb();
1956                 nr_devices = fs_info->fs_devices->open_devices;
1957                 ASSERT(nr_devices);
1958                 if (!nr_devices) {
1959                         *free_bytes = 0;
1960                         return 0;
1961                 }
1962         }
1963
1964         devices_info = kmalloc_array(nr_devices, sizeof(*devices_info),
1965                                GFP_KERNEL);
1966         if (!devices_info)
1967                 return -ENOMEM;
1968
1969         /* calc min stripe number for data space allocation */
1970         type = btrfs_data_alloc_profile(fs_info);
1971         if (type & BTRFS_BLOCK_GROUP_RAID0) {
1972                 min_stripes = 2;
1973                 num_stripes = nr_devices;
1974         } else if (type & BTRFS_BLOCK_GROUP_RAID1) {
1975                 min_stripes = 2;
1976                 num_stripes = 2;
1977         } else if (type & BTRFS_BLOCK_GROUP_RAID10) {
1978                 min_stripes = 4;
1979                 num_stripes = 4;
1980         }
1981
1982         if (type & BTRFS_BLOCK_GROUP_DUP)
1983                 min_stripe_size = 2 * BTRFS_STRIPE_LEN;
1984         else
1985                 min_stripe_size = BTRFS_STRIPE_LEN;
1986
1987         rcu_read_lock();
1988         list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
1989                 if (!test_bit(BTRFS_DEV_STATE_IN_FS_METADATA,
1990                                                 &device->dev_state) ||
1991                     !device->bdev ||
1992                     test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state))
1993                         continue;
1994
1995                 if (i >= nr_devices)
1996                         break;
1997
1998                 avail_space = device->total_bytes - device->bytes_used;
1999
2000                 /* align with stripe_len */
2001                 avail_space = div_u64(avail_space, BTRFS_STRIPE_LEN);
2002                 avail_space *= BTRFS_STRIPE_LEN;
2003
2004                 /*
2005                  * In order to avoid overwriting the superblock on the drive,
2006                  * btrfs starts at an offset of at least 1MB when doing chunk
2007                  * allocation.
2008                  */
2009                 skip_space = SZ_1M;
2010
2011                 /*
2012                  * we can use the free space in [0, skip_space - 1], subtract
2013                  * it from the total.
2014                  */
2015                 if (avail_space && avail_space >= skip_space)
2016                         avail_space -= skip_space;
2017                 else
2018                         avail_space = 0;
2019
2020                 if (avail_space < min_stripe_size)
2021                         continue;
2022
2023                 devices_info[i].dev = device;
2024                 devices_info[i].max_avail = avail_space;
2025
2026                 i++;
2027         }
2028         rcu_read_unlock();
2029
2030         nr_devices = i;
2031
2032         btrfs_descending_sort_devices(devices_info, nr_devices);
2033
2034         i = nr_devices - 1;
2035         avail_space = 0;
2036         while (nr_devices >= min_stripes) {
2037                 if (num_stripes > nr_devices)
2038                         num_stripes = nr_devices;
2039
2040                 if (devices_info[i].max_avail >= min_stripe_size) {
2041                         int j;
2042                         u64 alloc_size;
2043
2044                         avail_space += devices_info[i].max_avail * num_stripes;
2045                         alloc_size = devices_info[i].max_avail;
2046                         for (j = i + 1 - num_stripes; j <= i; j++)
2047                                 devices_info[j].max_avail -= alloc_size;
2048                 }
2049                 i--;
2050                 nr_devices--;
2051         }
2052
2053         kfree(devices_info);
2054         *free_bytes = avail_space;
2055         return 0;
2056 }
2057
2058 /*
2059  * Calculate numbers for 'df', pessimistic in case of mixed raid profiles.
2060  *
2061  * If there's a redundant raid level at DATA block groups, use the respective
2062  * multiplier to scale the sizes.
2063  *
2064  * Unused device space usage is based on simulating the chunk allocator
2065  * algorithm that respects the device sizes and order of allocations.  This is
2066  * a close approximation of the actual use but there are other factors that may
2067  * change the result (like a new metadata chunk).
2068  *
2069  * If metadata is exhausted, f_bavail will be 0.
2070  */
2071 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
2072 {
2073         struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
2074         struct btrfs_super_block *disk_super = fs_info->super_copy;
2075         struct list_head *head = &fs_info->space_info;
2076         struct btrfs_space_info *found;
2077         u64 total_used = 0;
2078         u64 total_free_data = 0;
2079         u64 total_free_meta = 0;
2080         int bits = dentry->d_sb->s_blocksize_bits;
2081         __be32 *fsid = (__be32 *)fs_info->fsid;
2082         unsigned factor = 1;
2083         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
2084         int ret;
2085         u64 thresh = 0;
2086         int mixed = 0;
2087
2088         rcu_read_lock();
2089         list_for_each_entry_rcu(found, head, list) {
2090                 if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
2091                         int i;
2092
2093                         total_free_data += found->disk_total - found->disk_used;
2094                         total_free_data -=
2095                                 btrfs_account_ro_block_groups_free_space(found);
2096
2097                         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
2098                                 if (!list_empty(&found->block_groups[i])) {
2099                                         switch (i) {
2100                                         case BTRFS_RAID_DUP:
2101                                         case BTRFS_RAID_RAID1:
2102                                         case BTRFS_RAID_RAID10:
2103                                                 factor = 2;
2104                                         }
2105                                 }
2106                         }
2107                 }
2108
2109                 /*
2110                  * Metadata in mixed block goup profiles are accounted in data
2111                  */
2112                 if (!mixed && found->flags & BTRFS_BLOCK_GROUP_METADATA) {
2113                         if (found->flags & BTRFS_BLOCK_GROUP_DATA)
2114                                 mixed = 1;
2115                         else
2116                                 total_free_meta += found->disk_total -
2117                                         found->disk_used;
2118                 }
2119
2120                 total_used += found->disk_used;
2121         }
2122
2123         rcu_read_unlock();
2124
2125         buf->f_blocks = div_u64(btrfs_super_total_bytes(disk_super), factor);
2126         buf->f_blocks >>= bits;
2127         buf->f_bfree = buf->f_blocks - (div_u64(total_used, factor) >> bits);
2128
2129         /* Account global block reserve as used, it's in logical size already */
2130         spin_lock(&block_rsv->lock);
2131         /* Mixed block groups accounting is not byte-accurate, avoid overflow */
2132         if (buf->f_bfree >= block_rsv->size >> bits)
2133                 buf->f_bfree -= block_rsv->size >> bits;
2134         else
2135                 buf->f_bfree = 0;
2136         spin_unlock(&block_rsv->lock);
2137
2138         buf->f_bavail = div_u64(total_free_data, factor);
2139         ret = btrfs_calc_avail_data_space(fs_info, &total_free_data);
2140         if (ret)
2141                 return ret;
2142         buf->f_bavail += div_u64(total_free_data, factor);
2143         buf->f_bavail = buf->f_bavail >> bits;
2144
2145         /*
2146          * We calculate the remaining metadata space minus global reserve. If
2147          * this is (supposedly) smaller than zero, there's no space. But this
2148          * does not hold in practice, the exhausted state happens where's still
2149          * some positive delta. So we apply some guesswork and compare the
2150          * delta to a 4M threshold.  (Practically observed delta was ~2M.)
2151          *
2152          * We probably cannot calculate the exact threshold value because this
2153          * depends on the internal reservations requested by various
2154          * operations, so some operations that consume a few metadata will
2155          * succeed even if the Avail is zero. But this is better than the other
2156          * way around.
2157          */
2158         thresh = SZ_4M;
2159
2160         if (!mixed && total_free_meta - thresh < block_rsv->size)
2161                 buf->f_bavail = 0;
2162
2163         buf->f_type = BTRFS_SUPER_MAGIC;
2164         buf->f_bsize = dentry->d_sb->s_blocksize;
2165         buf->f_namelen = BTRFS_NAME_LEN;
2166
2167         /* We treat it as constant endianness (it doesn't matter _which_)
2168            because we want the fsid to come out the same whether mounted
2169            on a big-endian or little-endian host */
2170         buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
2171         buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
2172         /* Mask in the root object ID too, to disambiguate subvols */
2173         buf->f_fsid.val[0] ^= BTRFS_I(d_inode(dentry))->root->objectid >> 32;
2174         buf->f_fsid.val[1] ^= BTRFS_I(d_inode(dentry))->root->objectid;
2175
2176         return 0;
2177 }
2178
2179 static void btrfs_kill_super(struct super_block *sb)
2180 {
2181         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2182         kill_anon_super(sb);
2183         free_fs_info(fs_info);
2184 }
2185
2186 static struct file_system_type btrfs_fs_type = {
2187         .owner          = THIS_MODULE,
2188         .name           = "btrfs",
2189         .mount          = btrfs_mount,
2190         .kill_sb        = btrfs_kill_super,
2191         .fs_flags       = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,
2192 };
2193
2194 static struct file_system_type btrfs_root_fs_type = {
2195         .owner          = THIS_MODULE,
2196         .name           = "btrfs",
2197         .mount          = btrfs_mount_root,
2198         .kill_sb        = btrfs_kill_super,
2199         .fs_flags       = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,
2200 };
2201
2202 MODULE_ALIAS_FS("btrfs");
2203
2204 static int btrfs_control_open(struct inode *inode, struct file *file)
2205 {
2206         /*
2207          * The control file's private_data is used to hold the
2208          * transaction when it is started and is used to keep
2209          * track of whether a transaction is already in progress.
2210          */
2211         file->private_data = NULL;
2212         return 0;
2213 }
2214
2215 /*
2216  * used by btrfsctl to scan devices when no FS is mounted
2217  */
2218 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
2219                                 unsigned long arg)
2220 {
2221         struct btrfs_ioctl_vol_args *vol;
2222         struct btrfs_fs_devices *fs_devices;
2223         int ret = -ENOTTY;
2224
2225         if (!capable(CAP_SYS_ADMIN))
2226                 return -EPERM;
2227
2228         vol = memdup_user((void __user *)arg, sizeof(*vol));
2229         if (IS_ERR(vol))
2230                 return PTR_ERR(vol);
2231
2232         switch (cmd) {
2233         case BTRFS_IOC_SCAN_DEV:
2234                 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
2235                                             &btrfs_root_fs_type, &fs_devices);
2236                 break;
2237         case BTRFS_IOC_DEVICES_READY:
2238                 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
2239                                             &btrfs_root_fs_type, &fs_devices);
2240                 if (ret)
2241                         break;
2242                 ret = !(fs_devices->num_devices == fs_devices->total_devices);
2243                 break;
2244         case BTRFS_IOC_GET_SUPPORTED_FEATURES:
2245                 ret = btrfs_ioctl_get_supported_features((void __user*)arg);
2246                 break;
2247         }
2248
2249         kfree(vol);
2250         return ret;
2251 }
2252
2253 static int btrfs_freeze(struct super_block *sb)
2254 {
2255         struct btrfs_trans_handle *trans;
2256         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2257         struct btrfs_root *root = fs_info->tree_root;
2258
2259         set_bit(BTRFS_FS_FROZEN, &fs_info->flags);
2260         /*
2261          * We don't need a barrier here, we'll wait for any transaction that
2262          * could be in progress on other threads (and do delayed iputs that
2263          * we want to avoid on a frozen filesystem), or do the commit
2264          * ourselves.
2265          */
2266         trans = btrfs_attach_transaction_barrier(root);
2267         if (IS_ERR(trans)) {
2268                 /* no transaction, don't bother */
2269                 if (PTR_ERR(trans) == -ENOENT)
2270                         return 0;
2271                 return PTR_ERR(trans);
2272         }
2273         return btrfs_commit_transaction(trans);
2274 }
2275
2276 static int btrfs_unfreeze(struct super_block *sb)
2277 {
2278         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2279
2280         clear_bit(BTRFS_FS_FROZEN, &fs_info->flags);
2281         return 0;
2282 }
2283
2284 static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
2285 {
2286         struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
2287         struct btrfs_fs_devices *cur_devices;
2288         struct btrfs_device *dev, *first_dev = NULL;
2289         struct list_head *head;
2290         struct rcu_string *name;
2291
2292         /*
2293          * Lightweight locking of the devices. We should not need
2294          * device_list_mutex here as we only read the device data and the list
2295          * is protected by RCU.  Even if a device is deleted during the list
2296          * traversals, we'll get valid data, the freeing callback will wait at
2297          * least until until the rcu_read_unlock.
2298          */
2299         rcu_read_lock();
2300         cur_devices = fs_info->fs_devices;
2301         while (cur_devices) {
2302                 head = &cur_devices->devices;
2303                 list_for_each_entry_rcu(dev, head, dev_list) {
2304                         if (test_bit(BTRFS_DEV_STATE_MISSING, &dev->dev_state))
2305                                 continue;
2306                         if (!dev->name)
2307                                 continue;
2308                         if (!first_dev || dev->devid < first_dev->devid)
2309                                 first_dev = dev;
2310                 }
2311                 cur_devices = cur_devices->seed;
2312         }
2313
2314         if (first_dev) {
2315                 name = rcu_dereference(first_dev->name);
2316                 seq_escape(m, name->str, " \t\n\\");
2317         } else {
2318                 WARN_ON(1);
2319         }
2320         rcu_read_unlock();
2321         return 0;
2322 }
2323
2324 static const struct super_operations btrfs_super_ops = {
2325         .drop_inode     = btrfs_drop_inode,
2326         .evict_inode    = btrfs_evict_inode,
2327         .put_super      = btrfs_put_super,
2328         .sync_fs        = btrfs_sync_fs,
2329         .show_options   = btrfs_show_options,
2330         .show_devname   = btrfs_show_devname,
2331         .write_inode    = btrfs_write_inode,
2332         .alloc_inode    = btrfs_alloc_inode,
2333         .destroy_inode  = btrfs_destroy_inode,
2334         .statfs         = btrfs_statfs,
2335         .remount_fs     = btrfs_remount,
2336         .freeze_fs      = btrfs_freeze,
2337         .unfreeze_fs    = btrfs_unfreeze,
2338 };
2339
2340 static const struct file_operations btrfs_ctl_fops = {
2341         .open = btrfs_control_open,
2342         .unlocked_ioctl  = btrfs_control_ioctl,
2343         .compat_ioctl = btrfs_control_ioctl,
2344         .owner   = THIS_MODULE,
2345         .llseek = noop_llseek,
2346 };
2347
2348 static struct miscdevice btrfs_misc = {
2349         .minor          = BTRFS_MINOR,
2350         .name           = "btrfs-control",
2351         .fops           = &btrfs_ctl_fops
2352 };
2353
2354 MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
2355 MODULE_ALIAS("devname:btrfs-control");
2356
2357 static int __init btrfs_interface_init(void)
2358 {
2359         return misc_register(&btrfs_misc);
2360 }
2361
2362 static __cold void btrfs_interface_exit(void)
2363 {
2364         misc_deregister(&btrfs_misc);
2365 }
2366
2367 static void __init btrfs_print_mod_info(void)
2368 {
2369         pr_info("Btrfs loaded, crc32c=%s"
2370 #ifdef CONFIG_BTRFS_DEBUG
2371                         ", debug=on"
2372 #endif
2373 #ifdef CONFIG_BTRFS_ASSERT
2374                         ", assert=on"
2375 #endif
2376 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
2377                         ", integrity-checker=on"
2378 #endif
2379 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
2380                         ", ref-verify=on"
2381 #endif
2382                         "\n",
2383                         crc32c_impl());
2384 }
2385
2386 static int __init init_btrfs_fs(void)
2387 {
2388         int err;
2389
2390         btrfs_props_init();
2391
2392         err = btrfs_init_sysfs();
2393         if (err)
2394                 return err;
2395
2396         btrfs_init_compress();
2397
2398         err = btrfs_init_cachep();
2399         if (err)
2400                 goto free_compress;
2401
2402         err = extent_io_init();
2403         if (err)
2404                 goto free_cachep;
2405
2406         err = extent_map_init();
2407         if (err)
2408                 goto free_extent_io;
2409
2410         err = ordered_data_init();
2411         if (err)
2412                 goto free_extent_map;
2413
2414         err = btrfs_delayed_inode_init();
2415         if (err)
2416                 goto free_ordered_data;
2417
2418         err = btrfs_auto_defrag_init();
2419         if (err)
2420                 goto free_delayed_inode;
2421
2422         err = btrfs_delayed_ref_init();
2423         if (err)
2424                 goto free_auto_defrag;
2425
2426         err = btrfs_prelim_ref_init();
2427         if (err)
2428                 goto free_delayed_ref;
2429
2430         err = btrfs_end_io_wq_init();
2431         if (err)
2432                 goto free_prelim_ref;
2433
2434         err = btrfs_interface_init();
2435         if (err)
2436                 goto free_end_io_wq;
2437
2438         btrfs_init_lockdep();
2439
2440         btrfs_print_mod_info();
2441
2442         err = btrfs_run_sanity_tests();
2443         if (err)
2444                 goto unregister_ioctl;
2445
2446         err = register_filesystem(&btrfs_fs_type);
2447         if (err)
2448                 goto unregister_ioctl;
2449
2450         return 0;
2451
2452 unregister_ioctl:
2453         btrfs_interface_exit();
2454 free_end_io_wq:
2455         btrfs_end_io_wq_exit();
2456 free_prelim_ref:
2457         btrfs_prelim_ref_exit();
2458 free_delayed_ref:
2459         btrfs_delayed_ref_exit();
2460 free_auto_defrag:
2461         btrfs_auto_defrag_exit();
2462 free_delayed_inode:
2463         btrfs_delayed_inode_exit();
2464 free_ordered_data:
2465         ordered_data_exit();
2466 free_extent_map:
2467         extent_map_exit();
2468 free_extent_io:
2469         extent_io_exit();
2470 free_cachep:
2471         btrfs_destroy_cachep();
2472 free_compress:
2473         btrfs_exit_compress();
2474         btrfs_exit_sysfs();
2475
2476         return err;
2477 }
2478
2479 static void __exit exit_btrfs_fs(void)
2480 {
2481         btrfs_destroy_cachep();
2482         btrfs_delayed_ref_exit();
2483         btrfs_auto_defrag_exit();
2484         btrfs_delayed_inode_exit();
2485         btrfs_prelim_ref_exit();
2486         ordered_data_exit();
2487         extent_map_exit();
2488         extent_io_exit();
2489         btrfs_interface_exit();
2490         btrfs_end_io_wq_exit();
2491         unregister_filesystem(&btrfs_fs_type);
2492         btrfs_exit_sysfs();
2493         btrfs_cleanup_fs_uuids();
2494         btrfs_exit_compress();
2495 }
2496
2497 late_initcall(init_btrfs_fs);
2498 module_exit(exit_btrfs_fs)
2499
2500 MODULE_LICENSE("GPL");