xref: /openbmc/linux/fs/btrfs/super.c (revision 206204a1)
1 /*
2  * Copyright (C) 2007 Oracle.  All rights reserved.
3  *
4  * This program is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU General Public
6  * License v2 as published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope that it will be useful,
9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
11  * General Public License for more details.
12  *
13  * You should have received a copy of the GNU General Public
14  * License along with this program; if not, write to the
15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16  * Boston, MA 021110-1307, USA.
17  */
18 
19 #include <linux/blkdev.h>
20 #include <linux/module.h>
21 #include <linux/buffer_head.h>
22 #include <linux/fs.h>
23 #include <linux/pagemap.h>
24 #include <linux/highmem.h>
25 #include <linux/time.h>
26 #include <linux/init.h>
27 #include <linux/seq_file.h>
28 #include <linux/string.h>
29 #include <linux/backing-dev.h>
30 #include <linux/mount.h>
31 #include <linux/mpage.h>
32 #include <linux/swap.h>
33 #include <linux/writeback.h>
34 #include <linux/statfs.h>
35 #include <linux/compat.h>
36 #include <linux/parser.h>
37 #include <linux/ctype.h>
38 #include <linux/namei.h>
39 #include <linux/miscdevice.h>
40 #include <linux/magic.h>
41 #include <linux/slab.h>
42 #include <linux/cleancache.h>
43 #include <linux/ratelimit.h>
44 #include <linux/btrfs.h>
45 #include "delayed-inode.h"
46 #include "ctree.h"
47 #include "disk-io.h"
48 #include "transaction.h"
49 #include "btrfs_inode.h"
50 #include "print-tree.h"
51 #include "hash.h"
52 #include "props.h"
53 #include "xattr.h"
54 #include "volumes.h"
55 #include "export.h"
56 #include "compression.h"
57 #include "rcu-string.h"
58 #include "dev-replace.h"
59 #include "free-space-cache.h"
60 #include "backref.h"
61 #include "tests/btrfs-tests.h"
62 
63 #define CREATE_TRACE_POINTS
64 #include <trace/events/btrfs.h>
65 
66 static const struct super_operations btrfs_super_ops;
67 static struct file_system_type btrfs_fs_type;
68 
69 static int btrfs_remount(struct super_block *sb, int *flags, char *data);
70 
71 static const char *btrfs_decode_error(int errno)
72 {
73 	char *errstr = "unknown";
74 
75 	switch (errno) {
76 	case -EIO:
77 		errstr = "IO failure";
78 		break;
79 	case -ENOMEM:
80 		errstr = "Out of memory";
81 		break;
82 	case -EROFS:
83 		errstr = "Readonly filesystem";
84 		break;
85 	case -EEXIST:
86 		errstr = "Object already exists";
87 		break;
88 	case -ENOSPC:
89 		errstr = "No space left";
90 		break;
91 	case -ENOENT:
92 		errstr = "No such entry";
93 		break;
94 	}
95 
96 	return errstr;
97 }
98 
99 static void save_error_info(struct btrfs_fs_info *fs_info)
100 {
101 	/*
102 	 * today we only save the error info into ram.  Long term we'll
103 	 * also send it down to the disk
104 	 */
105 	set_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state);
106 }
107 
108 /* btrfs handle error by forcing the filesystem readonly */
109 static void btrfs_handle_error(struct btrfs_fs_info *fs_info)
110 {
111 	struct super_block *sb = fs_info->sb;
112 
113 	if (sb->s_flags & MS_RDONLY)
114 		return;
115 
116 	if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
117 		sb->s_flags |= MS_RDONLY;
118 		btrfs_info(fs_info, "forced readonly");
119 		/*
120 		 * Note that a running device replace operation is not
121 		 * canceled here although there is no way to update
122 		 * the progress. It would add the risk of a deadlock,
123 		 * therefore the canceling is ommited. The only penalty
124 		 * is that some I/O remains active until the procedure
125 		 * completes. The next time when the filesystem is
126 		 * mounted writeable again, the device replace
127 		 * operation continues.
128 		 */
129 	}
130 }
131 
132 #ifdef CONFIG_PRINTK
133 /*
134  * __btrfs_std_error decodes expected errors from the caller and
135  * invokes the approciate error response.
136  */
137 void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function,
138 		       unsigned int line, int errno, const char *fmt, ...)
139 {
140 	struct super_block *sb = fs_info->sb;
141 	const char *errstr;
142 
143 	/*
144 	 * Special case: if the error is EROFS, and we're already
145 	 * under MS_RDONLY, then it is safe here.
146 	 */
147 	if (errno == -EROFS && (sb->s_flags & MS_RDONLY))
148   		return;
149 
150 	errstr = btrfs_decode_error(errno);
151 	if (fmt) {
152 		struct va_format vaf;
153 		va_list args;
154 
155 		va_start(args, fmt);
156 		vaf.fmt = fmt;
157 		vaf.va = &args;
158 
159 		printk(KERN_CRIT
160 			"BTRFS: error (device %s) in %s:%d: errno=%d %s (%pV)\n",
161 			sb->s_id, function, line, errno, errstr, &vaf);
162 		va_end(args);
163 	} else {
164 		printk(KERN_CRIT "BTRFS: error (device %s) in %s:%d: errno=%d %s\n",
165 			sb->s_id, function, line, errno, errstr);
166 	}
167 
168 	/* Don't go through full error handling during mount */
169 	save_error_info(fs_info);
170 	if (sb->s_flags & MS_BORN)
171 		btrfs_handle_error(fs_info);
172 }
173 
174 static const char * const logtypes[] = {
175 	"emergency",
176 	"alert",
177 	"critical",
178 	"error",
179 	"warning",
180 	"notice",
181 	"info",
182 	"debug",
183 };
184 
185 void btrfs_printk(const struct btrfs_fs_info *fs_info, const char *fmt, ...)
186 {
187 	struct super_block *sb = fs_info->sb;
188 	char lvl[4];
189 	struct va_format vaf;
190 	va_list args;
191 	const char *type = logtypes[4];
192 	int kern_level;
193 
194 	va_start(args, fmt);
195 
196 	kern_level = printk_get_level(fmt);
197 	if (kern_level) {
198 		size_t size = printk_skip_level(fmt) - fmt;
199 		memcpy(lvl, fmt,  size);
200 		lvl[size] = '\0';
201 		fmt += size;
202 		type = logtypes[kern_level - '0'];
203 	} else
204 		*lvl = '\0';
205 
206 	vaf.fmt = fmt;
207 	vaf.va = &args;
208 
209 	printk("%sBTRFS %s (device %s): %pV\n", lvl, type, sb->s_id, &vaf);
210 
211 	va_end(args);
212 }
213 
214 #else
215 
216 void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function,
217 		       unsigned int line, int errno, const char *fmt, ...)
218 {
219 	struct super_block *sb = fs_info->sb;
220 
221 	/*
222 	 * Special case: if the error is EROFS, and we're already
223 	 * under MS_RDONLY, then it is safe here.
224 	 */
225 	if (errno == -EROFS && (sb->s_flags & MS_RDONLY))
226 		return;
227 
228 	/* Don't go through full error handling during mount */
229 	if (sb->s_flags & MS_BORN) {
230 		save_error_info(fs_info);
231 		btrfs_handle_error(fs_info);
232 	}
233 }
234 #endif
235 
236 /*
237  * We only mark the transaction aborted and then set the file system read-only.
238  * This will prevent new transactions from starting or trying to join this
239  * one.
240  *
241  * This means that error recovery at the call site is limited to freeing
242  * any local memory allocations and passing the error code up without
243  * further cleanup. The transaction should complete as it normally would
244  * in the call path but will return -EIO.
245  *
246  * We'll complete the cleanup in btrfs_end_transaction and
247  * btrfs_commit_transaction.
248  */
249 void __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
250 			       struct btrfs_root *root, const char *function,
251 			       unsigned int line, int errno)
252 {
253 	/*
254 	 * Report first abort since mount
255 	 */
256 	if (!test_and_set_bit(BTRFS_FS_STATE_TRANS_ABORTED,
257 				&root->fs_info->fs_state)) {
258 		WARN(1, KERN_DEBUG "BTRFS: Transaction aborted (error %d)\n",
259 				errno);
260 	}
261 	trans->aborted = errno;
262 	/* Nothing used. The other threads that have joined this
263 	 * transaction may be able to continue. */
264 	if (!trans->blocks_used) {
265 		const char *errstr;
266 
267 		errstr = btrfs_decode_error(errno);
268 		btrfs_warn(root->fs_info,
269 		           "%s:%d: Aborting unused transaction(%s).",
270 		           function, line, errstr);
271 		return;
272 	}
273 	ACCESS_ONCE(trans->transaction->aborted) = errno;
274 	/* Wake up anybody who may be waiting on this transaction */
275 	wake_up(&root->fs_info->transaction_wait);
276 	wake_up(&root->fs_info->transaction_blocked_wait);
277 	__btrfs_std_error(root->fs_info, function, line, errno, NULL);
278 }
279 /*
280  * __btrfs_panic decodes unexpected, fatal errors from the caller,
281  * issues an alert, and either panics or BUGs, depending on mount options.
282  */
283 void __btrfs_panic(struct btrfs_fs_info *fs_info, const char *function,
284 		   unsigned int line, int errno, const char *fmt, ...)
285 {
286 	char *s_id = "<unknown>";
287 	const char *errstr;
288 	struct va_format vaf = { .fmt = fmt };
289 	va_list args;
290 
291 	if (fs_info)
292 		s_id = fs_info->sb->s_id;
293 
294 	va_start(args, fmt);
295 	vaf.va = &args;
296 
297 	errstr = btrfs_decode_error(errno);
298 	if (fs_info && (fs_info->mount_opt & BTRFS_MOUNT_PANIC_ON_FATAL_ERROR))
299 		panic(KERN_CRIT "BTRFS panic (device %s) in %s:%d: %pV (errno=%d %s)\n",
300 			s_id, function, line, &vaf, errno, errstr);
301 
302 	btrfs_crit(fs_info, "panic in %s:%d: %pV (errno=%d %s)",
303 		   function, line, &vaf, errno, errstr);
304 	va_end(args);
305 	/* Caller calls BUG() */
306 }
307 
308 static void btrfs_put_super(struct super_block *sb)
309 {
310 	(void)close_ctree(btrfs_sb(sb)->tree_root);
311 	/* FIXME: need to fix VFS to return error? */
312 	/* AV: return it _where_?  ->put_super() can be triggered by any number
313 	 * of async events, up to and including delivery of SIGKILL to the
314 	 * last process that kept it busy.  Or segfault in the aforementioned
315 	 * process...  Whom would you report that to?
316 	 */
317 }
318 
319 enum {
320 	Opt_degraded, Opt_subvol, Opt_subvolid, Opt_device, Opt_nodatasum,
321 	Opt_nodatacow, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd,
322 	Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl, Opt_compress,
323 	Opt_compress_type, Opt_compress_force, Opt_compress_force_type,
324 	Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard,
325 	Opt_space_cache, Opt_clear_cache, Opt_user_subvol_rm_allowed,
326 	Opt_enospc_debug, Opt_subvolrootid, Opt_defrag, Opt_inode_cache,
327 	Opt_no_space_cache, Opt_recovery, Opt_skip_balance,
328 	Opt_check_integrity, Opt_check_integrity_including_extent_data,
329 	Opt_check_integrity_print_mask, Opt_fatal_errors, Opt_rescan_uuid_tree,
330 	Opt_commit_interval, Opt_barrier, Opt_nodefrag, Opt_nodiscard,
331 	Opt_noenospc_debug, Opt_noflushoncommit, Opt_acl, Opt_datacow,
332 	Opt_datasum, Opt_treelog, Opt_noinode_cache,
333 	Opt_err,
334 };
335 
336 static match_table_t tokens = {
337 	{Opt_degraded, "degraded"},
338 	{Opt_subvol, "subvol=%s"},
339 	{Opt_subvolid, "subvolid=%s"},
340 	{Opt_device, "device=%s"},
341 	{Opt_nodatasum, "nodatasum"},
342 	{Opt_datasum, "datasum"},
343 	{Opt_nodatacow, "nodatacow"},
344 	{Opt_datacow, "datacow"},
345 	{Opt_nobarrier, "nobarrier"},
346 	{Opt_barrier, "barrier"},
347 	{Opt_max_inline, "max_inline=%s"},
348 	{Opt_alloc_start, "alloc_start=%s"},
349 	{Opt_thread_pool, "thread_pool=%d"},
350 	{Opt_compress, "compress"},
351 	{Opt_compress_type, "compress=%s"},
352 	{Opt_compress_force, "compress-force"},
353 	{Opt_compress_force_type, "compress-force=%s"},
354 	{Opt_ssd, "ssd"},
355 	{Opt_ssd_spread, "ssd_spread"},
356 	{Opt_nossd, "nossd"},
357 	{Opt_acl, "acl"},
358 	{Opt_noacl, "noacl"},
359 	{Opt_notreelog, "notreelog"},
360 	{Opt_treelog, "treelog"},
361 	{Opt_flushoncommit, "flushoncommit"},
362 	{Opt_noflushoncommit, "noflushoncommit"},
363 	{Opt_ratio, "metadata_ratio=%d"},
364 	{Opt_discard, "discard"},
365 	{Opt_nodiscard, "nodiscard"},
366 	{Opt_space_cache, "space_cache"},
367 	{Opt_clear_cache, "clear_cache"},
368 	{Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
369 	{Opt_enospc_debug, "enospc_debug"},
370 	{Opt_noenospc_debug, "noenospc_debug"},
371 	{Opt_subvolrootid, "subvolrootid=%d"},
372 	{Opt_defrag, "autodefrag"},
373 	{Opt_nodefrag, "noautodefrag"},
374 	{Opt_inode_cache, "inode_cache"},
375 	{Opt_noinode_cache, "noinode_cache"},
376 	{Opt_no_space_cache, "nospace_cache"},
377 	{Opt_recovery, "recovery"},
378 	{Opt_skip_balance, "skip_balance"},
379 	{Opt_check_integrity, "check_int"},
380 	{Opt_check_integrity_including_extent_data, "check_int_data"},
381 	{Opt_check_integrity_print_mask, "check_int_print_mask=%d"},
382 	{Opt_rescan_uuid_tree, "rescan_uuid_tree"},
383 	{Opt_fatal_errors, "fatal_errors=%s"},
384 	{Opt_commit_interval, "commit=%d"},
385 	{Opt_err, NULL},
386 };
387 
388 /*
389  * Regular mount options parser.  Everything that is needed only when
390  * reading in a new superblock is parsed here.
391  * XXX JDM: This needs to be cleaned up for remount.
392  */
393 int btrfs_parse_options(struct btrfs_root *root, char *options)
394 {
395 	struct btrfs_fs_info *info = root->fs_info;
396 	substring_t args[MAX_OPT_ARGS];
397 	char *p, *num, *orig = NULL;
398 	u64 cache_gen;
399 	int intarg;
400 	int ret = 0;
401 	char *compress_type;
402 	bool compress_force = false;
403 	bool compress = false;
404 
405 	cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
406 	if (cache_gen)
407 		btrfs_set_opt(info->mount_opt, SPACE_CACHE);
408 
409 	if (!options)
410 		goto out;
411 
412 	/*
413 	 * strsep changes the string, duplicate it because parse_options
414 	 * gets called twice
415 	 */
416 	options = kstrdup(options, GFP_NOFS);
417 	if (!options)
418 		return -ENOMEM;
419 
420 	orig = options;
421 
422 	while ((p = strsep(&options, ",")) != NULL) {
423 		int token;
424 		if (!*p)
425 			continue;
426 
427 		token = match_token(p, tokens, args);
428 		switch (token) {
429 		case Opt_degraded:
430 			btrfs_info(root->fs_info, "allowing degraded mounts");
431 			btrfs_set_opt(info->mount_opt, DEGRADED);
432 			break;
433 		case Opt_subvol:
434 		case Opt_subvolid:
435 		case Opt_subvolrootid:
436 		case Opt_device:
437 			/*
438 			 * These are parsed by btrfs_parse_early_options
439 			 * and can be happily ignored here.
440 			 */
441 			break;
442 		case Opt_nodatasum:
443 			btrfs_set_and_info(root, NODATASUM,
444 					   "setting nodatasum");
445 			break;
446 		case Opt_datasum:
447 			if (btrfs_test_opt(root, NODATASUM)) {
448 				if (btrfs_test_opt(root, NODATACOW))
449 					btrfs_info(root->fs_info, "setting datasum, datacow enabled");
450 				else
451 					btrfs_info(root->fs_info, "setting datasum");
452 			}
453 			btrfs_clear_opt(info->mount_opt, NODATACOW);
454 			btrfs_clear_opt(info->mount_opt, NODATASUM);
455 			break;
456 		case Opt_nodatacow:
457 			if (!btrfs_test_opt(root, NODATACOW)) {
458 				if (!btrfs_test_opt(root, COMPRESS) ||
459 				    !btrfs_test_opt(root, FORCE_COMPRESS)) {
460 					btrfs_info(root->fs_info,
461 						   "setting nodatacow, compression disabled");
462 				} else {
463 					btrfs_info(root->fs_info, "setting nodatacow");
464 				}
465 			}
466 			btrfs_clear_opt(info->mount_opt, COMPRESS);
467 			btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
468 			btrfs_set_opt(info->mount_opt, NODATACOW);
469 			btrfs_set_opt(info->mount_opt, NODATASUM);
470 			break;
471 		case Opt_datacow:
472 			btrfs_clear_and_info(root, NODATACOW,
473 					     "setting datacow");
474 			break;
475 		case Opt_compress_force:
476 		case Opt_compress_force_type:
477 			compress_force = true;
478 			/* Fallthrough */
479 		case Opt_compress:
480 		case Opt_compress_type:
481 			compress = true;
482 			if (token == Opt_compress ||
483 			    token == Opt_compress_force ||
484 			    strcmp(args[0].from, "zlib") == 0) {
485 				compress_type = "zlib";
486 				info->compress_type = BTRFS_COMPRESS_ZLIB;
487 				btrfs_set_opt(info->mount_opt, COMPRESS);
488 				btrfs_clear_opt(info->mount_opt, NODATACOW);
489 				btrfs_clear_opt(info->mount_opt, NODATASUM);
490 			} else if (strcmp(args[0].from, "lzo") == 0) {
491 				compress_type = "lzo";
492 				info->compress_type = BTRFS_COMPRESS_LZO;
493 				btrfs_set_opt(info->mount_opt, COMPRESS);
494 				btrfs_clear_opt(info->mount_opt, NODATACOW);
495 				btrfs_clear_opt(info->mount_opt, NODATASUM);
496 				btrfs_set_fs_incompat(info, COMPRESS_LZO);
497 			} else if (strncmp(args[0].from, "no", 2) == 0) {
498 				compress_type = "no";
499 				btrfs_clear_opt(info->mount_opt, COMPRESS);
500 				btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
501 				compress_force = false;
502 			} else {
503 				ret = -EINVAL;
504 				goto out;
505 			}
506 
507 			if (compress_force) {
508 				btrfs_set_and_info(root, FORCE_COMPRESS,
509 						   "force %s compression",
510 						   compress_type);
511 			} else if (compress) {
512 				if (!btrfs_test_opt(root, COMPRESS))
513 					btrfs_info(root->fs_info,
514 						   "btrfs: use %s compression",
515 						   compress_type);
516 			}
517 			break;
518 		case Opt_ssd:
519 			btrfs_set_and_info(root, SSD,
520 					   "use ssd allocation scheme");
521 			break;
522 		case Opt_ssd_spread:
523 			btrfs_set_and_info(root, SSD_SPREAD,
524 					   "use spread ssd allocation scheme");
525 			break;
526 		case Opt_nossd:
527 			btrfs_clear_and_info(root, NOSSD,
528 					     "not using ssd allocation scheme");
529 			btrfs_clear_opt(info->mount_opt, SSD);
530 			break;
531 		case Opt_barrier:
532 			btrfs_clear_and_info(root, NOBARRIER,
533 					     "turning on barriers");
534 			break;
535 		case Opt_nobarrier:
536 			btrfs_set_and_info(root, NOBARRIER,
537 					   "turning off barriers");
538 			break;
539 		case Opt_thread_pool:
540 			ret = match_int(&args[0], &intarg);
541 			if (ret) {
542 				goto out;
543 			} else if (intarg > 0) {
544 				info->thread_pool_size = intarg;
545 			} else {
546 				ret = -EINVAL;
547 				goto out;
548 			}
549 			break;
550 		case Opt_max_inline:
551 			num = match_strdup(&args[0]);
552 			if (num) {
553 				info->max_inline = memparse(num, NULL);
554 				kfree(num);
555 
556 				if (info->max_inline) {
557 					info->max_inline = min_t(u64,
558 						info->max_inline,
559 						root->sectorsize);
560 				}
561 				btrfs_info(root->fs_info, "max_inline at %llu",
562 					info->max_inline);
563 			} else {
564 				ret = -ENOMEM;
565 				goto out;
566 			}
567 			break;
568 		case Opt_alloc_start:
569 			num = match_strdup(&args[0]);
570 			if (num) {
571 				mutex_lock(&info->chunk_mutex);
572 				info->alloc_start = memparse(num, NULL);
573 				mutex_unlock(&info->chunk_mutex);
574 				kfree(num);
575 				btrfs_info(root->fs_info, "allocations start at %llu",
576 					info->alloc_start);
577 			} else {
578 				ret = -ENOMEM;
579 				goto out;
580 			}
581 			break;
582 		case Opt_acl:
583 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
584 			root->fs_info->sb->s_flags |= MS_POSIXACL;
585 			break;
586 #else
587 			btrfs_err(root->fs_info,
588 				"support for ACL not compiled in!");
589 			ret = -EINVAL;
590 			goto out;
591 #endif
592 		case Opt_noacl:
593 			root->fs_info->sb->s_flags &= ~MS_POSIXACL;
594 			break;
595 		case Opt_notreelog:
596 			btrfs_set_and_info(root, NOTREELOG,
597 					   "disabling tree log");
598 			break;
599 		case Opt_treelog:
600 			btrfs_clear_and_info(root, NOTREELOG,
601 					     "enabling tree log");
602 			break;
603 		case Opt_flushoncommit:
604 			btrfs_set_and_info(root, FLUSHONCOMMIT,
605 					   "turning on flush-on-commit");
606 			break;
607 		case Opt_noflushoncommit:
608 			btrfs_clear_and_info(root, FLUSHONCOMMIT,
609 					     "turning off flush-on-commit");
610 			break;
611 		case Opt_ratio:
612 			ret = match_int(&args[0], &intarg);
613 			if (ret) {
614 				goto out;
615 			} else if (intarg >= 0) {
616 				info->metadata_ratio = intarg;
617 				btrfs_info(root->fs_info, "metadata ratio %d",
618 				       info->metadata_ratio);
619 			} else {
620 				ret = -EINVAL;
621 				goto out;
622 			}
623 			break;
624 		case Opt_discard:
625 			btrfs_set_and_info(root, DISCARD,
626 					   "turning on discard");
627 			break;
628 		case Opt_nodiscard:
629 			btrfs_clear_and_info(root, DISCARD,
630 					     "turning off discard");
631 			break;
632 		case Opt_space_cache:
633 			btrfs_set_and_info(root, SPACE_CACHE,
634 					   "enabling disk space caching");
635 			break;
636 		case Opt_rescan_uuid_tree:
637 			btrfs_set_opt(info->mount_opt, RESCAN_UUID_TREE);
638 			break;
639 		case Opt_no_space_cache:
640 			btrfs_clear_and_info(root, SPACE_CACHE,
641 					     "disabling disk space caching");
642 			break;
643 		case Opt_inode_cache:
644 			btrfs_set_and_info(root, CHANGE_INODE_CACHE,
645 					   "enabling inode map caching");
646 			break;
647 		case Opt_noinode_cache:
648 			btrfs_clear_and_info(root, CHANGE_INODE_CACHE,
649 					     "disabling inode map caching");
650 			break;
651 		case Opt_clear_cache:
652 			btrfs_set_and_info(root, CLEAR_CACHE,
653 					   "force clearing of disk cache");
654 			break;
655 		case Opt_user_subvol_rm_allowed:
656 			btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
657 			break;
658 		case Opt_enospc_debug:
659 			btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
660 			break;
661 		case Opt_noenospc_debug:
662 			btrfs_clear_opt(info->mount_opt, ENOSPC_DEBUG);
663 			break;
664 		case Opt_defrag:
665 			btrfs_set_and_info(root, AUTO_DEFRAG,
666 					   "enabling auto defrag");
667 			break;
668 		case Opt_nodefrag:
669 			btrfs_clear_and_info(root, AUTO_DEFRAG,
670 					     "disabling auto defrag");
671 			break;
672 		case Opt_recovery:
673 			btrfs_info(root->fs_info, "enabling auto recovery");
674 			btrfs_set_opt(info->mount_opt, RECOVERY);
675 			break;
676 		case Opt_skip_balance:
677 			btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
678 			break;
679 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
680 		case Opt_check_integrity_including_extent_data:
681 			btrfs_info(root->fs_info,
682 				   "enabling check integrity including extent data");
683 			btrfs_set_opt(info->mount_opt,
684 				      CHECK_INTEGRITY_INCLUDING_EXTENT_DATA);
685 			btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
686 			break;
687 		case Opt_check_integrity:
688 			btrfs_info(root->fs_info, "enabling check integrity");
689 			btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
690 			break;
691 		case Opt_check_integrity_print_mask:
692 			ret = match_int(&args[0], &intarg);
693 			if (ret) {
694 				goto out;
695 			} else if (intarg >= 0) {
696 				info->check_integrity_print_mask = intarg;
697 				btrfs_info(root->fs_info, "check_integrity_print_mask 0x%x",
698 				       info->check_integrity_print_mask);
699 			} else {
700 				ret = -EINVAL;
701 				goto out;
702 			}
703 			break;
704 #else
705 		case Opt_check_integrity_including_extent_data:
706 		case Opt_check_integrity:
707 		case Opt_check_integrity_print_mask:
708 			btrfs_err(root->fs_info,
709 				"support for check_integrity* not compiled in!");
710 			ret = -EINVAL;
711 			goto out;
712 #endif
713 		case Opt_fatal_errors:
714 			if (strcmp(args[0].from, "panic") == 0)
715 				btrfs_set_opt(info->mount_opt,
716 					      PANIC_ON_FATAL_ERROR);
717 			else if (strcmp(args[0].from, "bug") == 0)
718 				btrfs_clear_opt(info->mount_opt,
719 					      PANIC_ON_FATAL_ERROR);
720 			else {
721 				ret = -EINVAL;
722 				goto out;
723 			}
724 			break;
725 		case Opt_commit_interval:
726 			intarg = 0;
727 			ret = match_int(&args[0], &intarg);
728 			if (ret < 0) {
729 				btrfs_err(root->fs_info, "invalid commit interval");
730 				ret = -EINVAL;
731 				goto out;
732 			}
733 			if (intarg > 0) {
734 				if (intarg > 300) {
735 					btrfs_warn(root->fs_info, "excessive commit interval %d",
736 							intarg);
737 				}
738 				info->commit_interval = intarg;
739 			} else {
740 				btrfs_info(root->fs_info, "using default commit interval %ds",
741 				    BTRFS_DEFAULT_COMMIT_INTERVAL);
742 				info->commit_interval = BTRFS_DEFAULT_COMMIT_INTERVAL;
743 			}
744 			break;
745 		case Opt_err:
746 			btrfs_info(root->fs_info, "unrecognized mount option '%s'", p);
747 			ret = -EINVAL;
748 			goto out;
749 		default:
750 			break;
751 		}
752 	}
753 out:
754 	if (!ret && btrfs_test_opt(root, SPACE_CACHE))
755 		btrfs_info(root->fs_info, "disk space caching is enabled");
756 	kfree(orig);
757 	return ret;
758 }
759 
760 /*
761  * Parse mount options that are required early in the mount process.
762  *
763  * All other options will be parsed on much later in the mount process and
764  * only when we need to allocate a new super block.
765  */
766 static int btrfs_parse_early_options(const char *options, fmode_t flags,
767 		void *holder, char **subvol_name, u64 *subvol_objectid,
768 		struct btrfs_fs_devices **fs_devices)
769 {
770 	substring_t args[MAX_OPT_ARGS];
771 	char *device_name, *opts, *orig, *p;
772 	char *num = NULL;
773 	int error = 0;
774 
775 	if (!options)
776 		return 0;
777 
778 	/*
779 	 * strsep changes the string, duplicate it because parse_options
780 	 * gets called twice
781 	 */
782 	opts = kstrdup(options, GFP_KERNEL);
783 	if (!opts)
784 		return -ENOMEM;
785 	orig = opts;
786 
787 	while ((p = strsep(&opts, ",")) != NULL) {
788 		int token;
789 		if (!*p)
790 			continue;
791 
792 		token = match_token(p, tokens, args);
793 		switch (token) {
794 		case Opt_subvol:
795 			kfree(*subvol_name);
796 			*subvol_name = match_strdup(&args[0]);
797 			if (!*subvol_name) {
798 				error = -ENOMEM;
799 				goto out;
800 			}
801 			break;
802 		case Opt_subvolid:
803 			num = match_strdup(&args[0]);
804 			if (num) {
805 				*subvol_objectid = memparse(num, NULL);
806 				kfree(num);
807 				/* we want the original fs_tree */
808 				if (!*subvol_objectid)
809 					*subvol_objectid =
810 						BTRFS_FS_TREE_OBJECTID;
811 			} else {
812 				error = -EINVAL;
813 				goto out;
814 			}
815 			break;
816 		case Opt_subvolrootid:
817 			printk(KERN_WARNING
818 				"BTRFS: 'subvolrootid' mount option is deprecated and has "
819 				"no effect\n");
820 			break;
821 		case Opt_device:
822 			device_name = match_strdup(&args[0]);
823 			if (!device_name) {
824 				error = -ENOMEM;
825 				goto out;
826 			}
827 			error = btrfs_scan_one_device(device_name,
828 					flags, holder, fs_devices);
829 			kfree(device_name);
830 			if (error)
831 				goto out;
832 			break;
833 		default:
834 			break;
835 		}
836 	}
837 
838 out:
839 	kfree(orig);
840 	return error;
841 }
842 
843 static struct dentry *get_default_root(struct super_block *sb,
844 				       u64 subvol_objectid)
845 {
846 	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
847 	struct btrfs_root *root = fs_info->tree_root;
848 	struct btrfs_root *new_root;
849 	struct btrfs_dir_item *di;
850 	struct btrfs_path *path;
851 	struct btrfs_key location;
852 	struct inode *inode;
853 	struct dentry *dentry;
854 	u64 dir_id;
855 	int new = 0;
856 
857 	/*
858 	 * We have a specific subvol we want to mount, just setup location and
859 	 * go look up the root.
860 	 */
861 	if (subvol_objectid) {
862 		location.objectid = subvol_objectid;
863 		location.type = BTRFS_ROOT_ITEM_KEY;
864 		location.offset = (u64)-1;
865 		goto find_root;
866 	}
867 
868 	path = btrfs_alloc_path();
869 	if (!path)
870 		return ERR_PTR(-ENOMEM);
871 	path->leave_spinning = 1;
872 
873 	/*
874 	 * Find the "default" dir item which points to the root item that we
875 	 * will mount by default if we haven't been given a specific subvolume
876 	 * to mount.
877 	 */
878 	dir_id = btrfs_super_root_dir(fs_info->super_copy);
879 	di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
880 	if (IS_ERR(di)) {
881 		btrfs_free_path(path);
882 		return ERR_CAST(di);
883 	}
884 	if (!di) {
885 		/*
886 		 * Ok the default dir item isn't there.  This is weird since
887 		 * it's always been there, but don't freak out, just try and
888 		 * mount to root most subvolume.
889 		 */
890 		btrfs_free_path(path);
891 		dir_id = BTRFS_FIRST_FREE_OBJECTID;
892 		new_root = fs_info->fs_root;
893 		goto setup_root;
894 	}
895 
896 	btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
897 	btrfs_free_path(path);
898 
899 find_root:
900 	new_root = btrfs_read_fs_root_no_name(fs_info, &location);
901 	if (IS_ERR(new_root))
902 		return ERR_CAST(new_root);
903 
904 	dir_id = btrfs_root_dirid(&new_root->root_item);
905 setup_root:
906 	location.objectid = dir_id;
907 	location.type = BTRFS_INODE_ITEM_KEY;
908 	location.offset = 0;
909 
910 	inode = btrfs_iget(sb, &location, new_root, &new);
911 	if (IS_ERR(inode))
912 		return ERR_CAST(inode);
913 
914 	/*
915 	 * If we're just mounting the root most subvol put the inode and return
916 	 * a reference to the dentry.  We will have already gotten a reference
917 	 * to the inode in btrfs_fill_super so we're good to go.
918 	 */
919 	if (!new && sb->s_root->d_inode == inode) {
920 		iput(inode);
921 		return dget(sb->s_root);
922 	}
923 
924 	dentry = d_obtain_alias(inode);
925 	if (!IS_ERR(dentry)) {
926 		spin_lock(&dentry->d_lock);
927 		dentry->d_flags &= ~DCACHE_DISCONNECTED;
928 		spin_unlock(&dentry->d_lock);
929 	}
930 	return dentry;
931 }
932 
933 static int btrfs_fill_super(struct super_block *sb,
934 			    struct btrfs_fs_devices *fs_devices,
935 			    void *data, int silent)
936 {
937 	struct inode *inode;
938 	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
939 	struct btrfs_key key;
940 	int err;
941 
942 	sb->s_maxbytes = MAX_LFS_FILESIZE;
943 	sb->s_magic = BTRFS_SUPER_MAGIC;
944 	sb->s_op = &btrfs_super_ops;
945 	sb->s_d_op = &btrfs_dentry_operations;
946 	sb->s_export_op = &btrfs_export_ops;
947 	sb->s_xattr = btrfs_xattr_handlers;
948 	sb->s_time_gran = 1;
949 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
950 	sb->s_flags |= MS_POSIXACL;
951 #endif
952 	sb->s_flags |= MS_I_VERSION;
953 	err = open_ctree(sb, fs_devices, (char *)data);
954 	if (err) {
955 		printk(KERN_ERR "BTRFS: open_ctree failed\n");
956 		return err;
957 	}
958 
959 	key.objectid = BTRFS_FIRST_FREE_OBJECTID;
960 	key.type = BTRFS_INODE_ITEM_KEY;
961 	key.offset = 0;
962 	inode = btrfs_iget(sb, &key, fs_info->fs_root, NULL);
963 	if (IS_ERR(inode)) {
964 		err = PTR_ERR(inode);
965 		goto fail_close;
966 	}
967 
968 	sb->s_root = d_make_root(inode);
969 	if (!sb->s_root) {
970 		err = -ENOMEM;
971 		goto fail_close;
972 	}
973 
974 	save_mount_options(sb, data);
975 	cleancache_init_fs(sb);
976 	sb->s_flags |= MS_ACTIVE;
977 	return 0;
978 
979 fail_close:
980 	close_ctree(fs_info->tree_root);
981 	return err;
982 }
983 
984 int btrfs_sync_fs(struct super_block *sb, int wait)
985 {
986 	struct btrfs_trans_handle *trans;
987 	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
988 	struct btrfs_root *root = fs_info->tree_root;
989 
990 	trace_btrfs_sync_fs(wait);
991 
992 	if (!wait) {
993 		filemap_flush(fs_info->btree_inode->i_mapping);
994 		return 0;
995 	}
996 
997 	btrfs_wait_ordered_roots(fs_info, -1);
998 
999 	trans = btrfs_attach_transaction_barrier(root);
1000 	if (IS_ERR(trans)) {
1001 		/* no transaction, don't bother */
1002 		if (PTR_ERR(trans) == -ENOENT)
1003 			return 0;
1004 		return PTR_ERR(trans);
1005 	}
1006 	return btrfs_commit_transaction(trans, root);
1007 }
1008 
1009 static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
1010 {
1011 	struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
1012 	struct btrfs_root *root = info->tree_root;
1013 	char *compress_type;
1014 
1015 	if (btrfs_test_opt(root, DEGRADED))
1016 		seq_puts(seq, ",degraded");
1017 	if (btrfs_test_opt(root, NODATASUM))
1018 		seq_puts(seq, ",nodatasum");
1019 	if (btrfs_test_opt(root, NODATACOW))
1020 		seq_puts(seq, ",nodatacow");
1021 	if (btrfs_test_opt(root, NOBARRIER))
1022 		seq_puts(seq, ",nobarrier");
1023 	if (info->max_inline != 8192 * 1024)
1024 		seq_printf(seq, ",max_inline=%llu", info->max_inline);
1025 	if (info->alloc_start != 0)
1026 		seq_printf(seq, ",alloc_start=%llu", info->alloc_start);
1027 	if (info->thread_pool_size !=  min_t(unsigned long,
1028 					     num_online_cpus() + 2, 8))
1029 		seq_printf(seq, ",thread_pool=%d", info->thread_pool_size);
1030 	if (btrfs_test_opt(root, COMPRESS)) {
1031 		if (info->compress_type == BTRFS_COMPRESS_ZLIB)
1032 			compress_type = "zlib";
1033 		else
1034 			compress_type = "lzo";
1035 		if (btrfs_test_opt(root, FORCE_COMPRESS))
1036 			seq_printf(seq, ",compress-force=%s", compress_type);
1037 		else
1038 			seq_printf(seq, ",compress=%s", compress_type);
1039 	}
1040 	if (btrfs_test_opt(root, NOSSD))
1041 		seq_puts(seq, ",nossd");
1042 	if (btrfs_test_opt(root, SSD_SPREAD))
1043 		seq_puts(seq, ",ssd_spread");
1044 	else if (btrfs_test_opt(root, SSD))
1045 		seq_puts(seq, ",ssd");
1046 	if (btrfs_test_opt(root, NOTREELOG))
1047 		seq_puts(seq, ",notreelog");
1048 	if (btrfs_test_opt(root, FLUSHONCOMMIT))
1049 		seq_puts(seq, ",flushoncommit");
1050 	if (btrfs_test_opt(root, DISCARD))
1051 		seq_puts(seq, ",discard");
1052 	if (!(root->fs_info->sb->s_flags & MS_POSIXACL))
1053 		seq_puts(seq, ",noacl");
1054 	if (btrfs_test_opt(root, SPACE_CACHE))
1055 		seq_puts(seq, ",space_cache");
1056 	else
1057 		seq_puts(seq, ",nospace_cache");
1058 	if (btrfs_test_opt(root, RESCAN_UUID_TREE))
1059 		seq_puts(seq, ",rescan_uuid_tree");
1060 	if (btrfs_test_opt(root, CLEAR_CACHE))
1061 		seq_puts(seq, ",clear_cache");
1062 	if (btrfs_test_opt(root, USER_SUBVOL_RM_ALLOWED))
1063 		seq_puts(seq, ",user_subvol_rm_allowed");
1064 	if (btrfs_test_opt(root, ENOSPC_DEBUG))
1065 		seq_puts(seq, ",enospc_debug");
1066 	if (btrfs_test_opt(root, AUTO_DEFRAG))
1067 		seq_puts(seq, ",autodefrag");
1068 	if (btrfs_test_opt(root, INODE_MAP_CACHE))
1069 		seq_puts(seq, ",inode_cache");
1070 	if (btrfs_test_opt(root, SKIP_BALANCE))
1071 		seq_puts(seq, ",skip_balance");
1072 	if (btrfs_test_opt(root, RECOVERY))
1073 		seq_puts(seq, ",recovery");
1074 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
1075 	if (btrfs_test_opt(root, CHECK_INTEGRITY_INCLUDING_EXTENT_DATA))
1076 		seq_puts(seq, ",check_int_data");
1077 	else if (btrfs_test_opt(root, CHECK_INTEGRITY))
1078 		seq_puts(seq, ",check_int");
1079 	if (info->check_integrity_print_mask)
1080 		seq_printf(seq, ",check_int_print_mask=%d",
1081 				info->check_integrity_print_mask);
1082 #endif
1083 	if (info->metadata_ratio)
1084 		seq_printf(seq, ",metadata_ratio=%d",
1085 				info->metadata_ratio);
1086 	if (btrfs_test_opt(root, PANIC_ON_FATAL_ERROR))
1087 		seq_puts(seq, ",fatal_errors=panic");
1088 	if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL)
1089 		seq_printf(seq, ",commit=%d", info->commit_interval);
1090 	return 0;
1091 }
1092 
1093 static int btrfs_test_super(struct super_block *s, void *data)
1094 {
1095 	struct btrfs_fs_info *p = data;
1096 	struct btrfs_fs_info *fs_info = btrfs_sb(s);
1097 
1098 	return fs_info->fs_devices == p->fs_devices;
1099 }
1100 
1101 static int btrfs_set_super(struct super_block *s, void *data)
1102 {
1103 	int err = set_anon_super(s, data);
1104 	if (!err)
1105 		s->s_fs_info = data;
1106 	return err;
1107 }
1108 
1109 /*
1110  * subvolumes are identified by ino 256
1111  */
1112 static inline int is_subvolume_inode(struct inode *inode)
1113 {
1114 	if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
1115 		return 1;
1116 	return 0;
1117 }
1118 
1119 /*
1120  * This will strip out the subvol=%s argument for an argument string and add
1121  * subvolid=0 to make sure we get the actual tree root for path walking to the
1122  * subvol we want.
1123  */
1124 static char *setup_root_args(char *args)
1125 {
1126 	unsigned len = strlen(args) + 2 + 1;
1127 	char *src, *dst, *buf;
1128 
1129 	/*
1130 	 * We need the same args as before, but with this substitution:
1131 	 * s!subvol=[^,]+!subvolid=0!
1132 	 *
1133 	 * Since the replacement string is up to 2 bytes longer than the
1134 	 * original, allocate strlen(args) + 2 + 1 bytes.
1135 	 */
1136 
1137 	src = strstr(args, "subvol=");
1138 	/* This shouldn't happen, but just in case.. */
1139 	if (!src)
1140 		return NULL;
1141 
1142 	buf = dst = kmalloc(len, GFP_NOFS);
1143 	if (!buf)
1144 		return NULL;
1145 
1146 	/*
1147 	 * If the subvol= arg is not at the start of the string,
1148 	 * copy whatever precedes it into buf.
1149 	 */
1150 	if (src != args) {
1151 		*src++ = '\0';
1152 		strcpy(buf, args);
1153 		dst += strlen(args);
1154 	}
1155 
1156 	strcpy(dst, "subvolid=0");
1157 	dst += strlen("subvolid=0");
1158 
1159 	/*
1160 	 * If there is a "," after the original subvol=... string,
1161 	 * copy that suffix into our buffer.  Otherwise, we're done.
1162 	 */
1163 	src = strchr(src, ',');
1164 	if (src)
1165 		strcpy(dst, src);
1166 
1167 	return buf;
1168 }
1169 
1170 static struct dentry *mount_subvol(const char *subvol_name, int flags,
1171 				   const char *device_name, char *data)
1172 {
1173 	struct dentry *root;
1174 	struct vfsmount *mnt;
1175 	char *newargs;
1176 
1177 	newargs = setup_root_args(data);
1178 	if (!newargs)
1179 		return ERR_PTR(-ENOMEM);
1180 	mnt = vfs_kern_mount(&btrfs_fs_type, flags, device_name,
1181 			     newargs);
1182 
1183 	if (PTR_RET(mnt) == -EBUSY) {
1184 		if (flags & MS_RDONLY) {
1185 			mnt = vfs_kern_mount(&btrfs_fs_type, flags & ~MS_RDONLY, device_name,
1186 					     newargs);
1187 		} else {
1188 			int r;
1189 			mnt = vfs_kern_mount(&btrfs_fs_type, flags | MS_RDONLY, device_name,
1190 					     newargs);
1191 			if (IS_ERR(mnt)) {
1192 				kfree(newargs);
1193 				return ERR_CAST(mnt);
1194 			}
1195 
1196 			r = btrfs_remount(mnt->mnt_sb, &flags, NULL);
1197 			if (r < 0) {
1198 				/* FIXME: release vfsmount mnt ??*/
1199 				kfree(newargs);
1200 				return ERR_PTR(r);
1201 			}
1202 		}
1203 	}
1204 
1205 	kfree(newargs);
1206 
1207 	if (IS_ERR(mnt))
1208 		return ERR_CAST(mnt);
1209 
1210 	root = mount_subtree(mnt, subvol_name);
1211 
1212 	if (!IS_ERR(root) && !is_subvolume_inode(root->d_inode)) {
1213 		struct super_block *s = root->d_sb;
1214 		dput(root);
1215 		root = ERR_PTR(-EINVAL);
1216 		deactivate_locked_super(s);
1217 		printk(KERN_ERR "BTRFS: '%s' is not a valid subvolume\n",
1218 				subvol_name);
1219 	}
1220 
1221 	return root;
1222 }
1223 
1224 /*
1225  * Find a superblock for the given device / mount point.
1226  *
1227  * Note:  This is based on get_sb_bdev from fs/super.c with a few additions
1228  *	  for multiple device setup.  Make sure to keep it in sync.
1229  */
1230 static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
1231 		const char *device_name, void *data)
1232 {
1233 	struct block_device *bdev = NULL;
1234 	struct super_block *s;
1235 	struct dentry *root;
1236 	struct btrfs_fs_devices *fs_devices = NULL;
1237 	struct btrfs_fs_info *fs_info = NULL;
1238 	fmode_t mode = FMODE_READ;
1239 	char *subvol_name = NULL;
1240 	u64 subvol_objectid = 0;
1241 	int error = 0;
1242 
1243 	if (!(flags & MS_RDONLY))
1244 		mode |= FMODE_WRITE;
1245 
1246 	error = btrfs_parse_early_options(data, mode, fs_type,
1247 					  &subvol_name, &subvol_objectid,
1248 					  &fs_devices);
1249 	if (error) {
1250 		kfree(subvol_name);
1251 		return ERR_PTR(error);
1252 	}
1253 
1254 	if (subvol_name) {
1255 		root = mount_subvol(subvol_name, flags, device_name, data);
1256 		kfree(subvol_name);
1257 		return root;
1258 	}
1259 
1260 	error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices);
1261 	if (error)
1262 		return ERR_PTR(error);
1263 
1264 	/*
1265 	 * Setup a dummy root and fs_info for test/set super.  This is because
1266 	 * we don't actually fill this stuff out until open_ctree, but we need
1267 	 * it for searching for existing supers, so this lets us do that and
1268 	 * then open_ctree will properly initialize everything later.
1269 	 */
1270 	fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_NOFS);
1271 	if (!fs_info)
1272 		return ERR_PTR(-ENOMEM);
1273 
1274 	fs_info->fs_devices = fs_devices;
1275 
1276 	fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
1277 	fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
1278 	if (!fs_info->super_copy || !fs_info->super_for_commit) {
1279 		error = -ENOMEM;
1280 		goto error_fs_info;
1281 	}
1282 
1283 	error = btrfs_open_devices(fs_devices, mode, fs_type);
1284 	if (error)
1285 		goto error_fs_info;
1286 
1287 	if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
1288 		error = -EACCES;
1289 		goto error_close_devices;
1290 	}
1291 
1292 	bdev = fs_devices->latest_bdev;
1293 	s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | MS_NOSEC,
1294 		 fs_info);
1295 	if (IS_ERR(s)) {
1296 		error = PTR_ERR(s);
1297 		goto error_close_devices;
1298 	}
1299 
1300 	if (s->s_root) {
1301 		btrfs_close_devices(fs_devices);
1302 		free_fs_info(fs_info);
1303 		if ((flags ^ s->s_flags) & MS_RDONLY)
1304 			error = -EBUSY;
1305 	} else {
1306 		char b[BDEVNAME_SIZE];
1307 
1308 		strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
1309 		btrfs_sb(s)->bdev_holder = fs_type;
1310 		error = btrfs_fill_super(s, fs_devices, data,
1311 					 flags & MS_SILENT ? 1 : 0);
1312 	}
1313 
1314 	root = !error ? get_default_root(s, subvol_objectid) : ERR_PTR(error);
1315 	if (IS_ERR(root))
1316 		deactivate_locked_super(s);
1317 
1318 	return root;
1319 
1320 error_close_devices:
1321 	btrfs_close_devices(fs_devices);
1322 error_fs_info:
1323 	free_fs_info(fs_info);
1324 	return ERR_PTR(error);
1325 }
1326 
1327 static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
1328 				     int new_pool_size, int old_pool_size)
1329 {
1330 	if (new_pool_size == old_pool_size)
1331 		return;
1332 
1333 	fs_info->thread_pool_size = new_pool_size;
1334 
1335 	btrfs_info(fs_info, "resize thread pool %d -> %d",
1336 	       old_pool_size, new_pool_size);
1337 
1338 	btrfs_workqueue_set_max(fs_info->workers, new_pool_size);
1339 	btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size);
1340 	btrfs_workqueue_set_max(fs_info->submit_workers, new_pool_size);
1341 	btrfs_workqueue_set_max(fs_info->caching_workers, new_pool_size);
1342 	btrfs_workqueue_set_max(fs_info->endio_workers, new_pool_size);
1343 	btrfs_workqueue_set_max(fs_info->endio_meta_workers, new_pool_size);
1344 	btrfs_workqueue_set_max(fs_info->endio_meta_write_workers,
1345 				new_pool_size);
1346 	btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size);
1347 	btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
1348 	btrfs_workqueue_set_max(fs_info->delayed_workers, new_pool_size);
1349 	btrfs_workqueue_set_max(fs_info->readahead_workers, new_pool_size);
1350 	btrfs_workqueue_set_max(fs_info->scrub_wr_completion_workers,
1351 				new_pool_size);
1352 }
1353 
1354 static inline void btrfs_remount_prepare(struct btrfs_fs_info *fs_info)
1355 {
1356 	set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1357 }
1358 
1359 static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info,
1360 				       unsigned long old_opts, int flags)
1361 {
1362 	if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1363 	    (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1364 	     (flags & MS_RDONLY))) {
1365 		/* wait for any defraggers to finish */
1366 		wait_event(fs_info->transaction_wait,
1367 			   (atomic_read(&fs_info->defrag_running) == 0));
1368 		if (flags & MS_RDONLY)
1369 			sync_filesystem(fs_info->sb);
1370 	}
1371 }
1372 
1373 static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
1374 					 unsigned long old_opts)
1375 {
1376 	/*
1377 	 * We need cleanup all defragable inodes if the autodefragment is
1378 	 * close or the fs is R/O.
1379 	 */
1380 	if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
1381 	    (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
1382 	     (fs_info->sb->s_flags & MS_RDONLY))) {
1383 		btrfs_cleanup_defrag_inodes(fs_info);
1384 	}
1385 
1386 	clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
1387 }
1388 
1389 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
1390 {
1391 	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1392 	struct btrfs_root *root = fs_info->tree_root;
1393 	unsigned old_flags = sb->s_flags;
1394 	unsigned long old_opts = fs_info->mount_opt;
1395 	unsigned long old_compress_type = fs_info->compress_type;
1396 	u64 old_max_inline = fs_info->max_inline;
1397 	u64 old_alloc_start = fs_info->alloc_start;
1398 	int old_thread_pool_size = fs_info->thread_pool_size;
1399 	unsigned int old_metadata_ratio = fs_info->metadata_ratio;
1400 	int ret;
1401 
1402 	sync_filesystem(sb);
1403 	btrfs_remount_prepare(fs_info);
1404 
1405 	ret = btrfs_parse_options(root, data);
1406 	if (ret) {
1407 		ret = -EINVAL;
1408 		goto restore;
1409 	}
1410 
1411 	btrfs_remount_begin(fs_info, old_opts, *flags);
1412 	btrfs_resize_thread_pool(fs_info,
1413 		fs_info->thread_pool_size, old_thread_pool_size);
1414 
1415 	if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1416 		goto out;
1417 
1418 	if (*flags & MS_RDONLY) {
1419 		/*
1420 		 * this also happens on 'umount -rf' or on shutdown, when
1421 		 * the filesystem is busy.
1422 		 */
1423 		cancel_work_sync(&fs_info->async_reclaim_work);
1424 
1425 		/* wait for the uuid_scan task to finish */
1426 		down(&fs_info->uuid_tree_rescan_sem);
1427 		/* avoid complains from lockdep et al. */
1428 		up(&fs_info->uuid_tree_rescan_sem);
1429 
1430 		sb->s_flags |= MS_RDONLY;
1431 
1432 		btrfs_dev_replace_suspend_for_unmount(fs_info);
1433 		btrfs_scrub_cancel(fs_info);
1434 		btrfs_pause_balance(fs_info);
1435 
1436 		ret = btrfs_commit_super(root);
1437 		if (ret)
1438 			goto restore;
1439 	} else {
1440 		if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state)) {
1441 			btrfs_err(fs_info,
1442 				"Remounting read-write after error is not allowed");
1443 			ret = -EINVAL;
1444 			goto restore;
1445 		}
1446 		if (fs_info->fs_devices->rw_devices == 0) {
1447 			ret = -EACCES;
1448 			goto restore;
1449 		}
1450 
1451 		if (fs_info->fs_devices->missing_devices >
1452 		     fs_info->num_tolerated_disk_barrier_failures &&
1453 		    !(*flags & MS_RDONLY)) {
1454 			btrfs_warn(fs_info,
1455 				"too many missing devices, writeable remount is not allowed");
1456 			ret = -EACCES;
1457 			goto restore;
1458 		}
1459 
1460 		if (btrfs_super_log_root(fs_info->super_copy) != 0) {
1461 			ret = -EINVAL;
1462 			goto restore;
1463 		}
1464 
1465 		ret = btrfs_cleanup_fs_roots(fs_info);
1466 		if (ret)
1467 			goto restore;
1468 
1469 		/* recover relocation */
1470 		ret = btrfs_recover_relocation(root);
1471 		if (ret)
1472 			goto restore;
1473 
1474 		ret = btrfs_resume_balance_async(fs_info);
1475 		if (ret)
1476 			goto restore;
1477 
1478 		ret = btrfs_resume_dev_replace_async(fs_info);
1479 		if (ret) {
1480 			btrfs_warn(fs_info, "failed to resume dev_replace");
1481 			goto restore;
1482 		}
1483 
1484 		if (!fs_info->uuid_root) {
1485 			btrfs_info(fs_info, "creating UUID tree");
1486 			ret = btrfs_create_uuid_tree(fs_info);
1487 			if (ret) {
1488 				btrfs_warn(fs_info, "failed to create the UUID tree %d", ret);
1489 				goto restore;
1490 			}
1491 		}
1492 		sb->s_flags &= ~MS_RDONLY;
1493 	}
1494 out:
1495 	wake_up_process(fs_info->transaction_kthread);
1496 	btrfs_remount_cleanup(fs_info, old_opts);
1497 	return 0;
1498 
1499 restore:
1500 	/* We've hit an error - don't reset MS_RDONLY */
1501 	if (sb->s_flags & MS_RDONLY)
1502 		old_flags |= MS_RDONLY;
1503 	sb->s_flags = old_flags;
1504 	fs_info->mount_opt = old_opts;
1505 	fs_info->compress_type = old_compress_type;
1506 	fs_info->max_inline = old_max_inline;
1507 	mutex_lock(&fs_info->chunk_mutex);
1508 	fs_info->alloc_start = old_alloc_start;
1509 	mutex_unlock(&fs_info->chunk_mutex);
1510 	btrfs_resize_thread_pool(fs_info,
1511 		old_thread_pool_size, fs_info->thread_pool_size);
1512 	fs_info->metadata_ratio = old_metadata_ratio;
1513 	btrfs_remount_cleanup(fs_info, old_opts);
1514 	return ret;
1515 }
1516 
1517 /* Used to sort the devices by max_avail(descending sort) */
1518 static int btrfs_cmp_device_free_bytes(const void *dev_info1,
1519 				       const void *dev_info2)
1520 {
1521 	if (((struct btrfs_device_info *)dev_info1)->max_avail >
1522 	    ((struct btrfs_device_info *)dev_info2)->max_avail)
1523 		return -1;
1524 	else if (((struct btrfs_device_info *)dev_info1)->max_avail <
1525 		 ((struct btrfs_device_info *)dev_info2)->max_avail)
1526 		return 1;
1527 	else
1528 	return 0;
1529 }
1530 
1531 /*
1532  * sort the devices by max_avail, in which max free extent size of each device
1533  * is stored.(Descending Sort)
1534  */
1535 static inline void btrfs_descending_sort_devices(
1536 					struct btrfs_device_info *devices,
1537 					size_t nr_devices)
1538 {
1539 	sort(devices, nr_devices, sizeof(struct btrfs_device_info),
1540 	     btrfs_cmp_device_free_bytes, NULL);
1541 }
1542 
1543 /*
1544  * The helper to calc the free space on the devices that can be used to store
1545  * file data.
1546  */
1547 static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes)
1548 {
1549 	struct btrfs_fs_info *fs_info = root->fs_info;
1550 	struct btrfs_device_info *devices_info;
1551 	struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
1552 	struct btrfs_device *device;
1553 	u64 skip_space;
1554 	u64 type;
1555 	u64 avail_space;
1556 	u64 used_space;
1557 	u64 min_stripe_size;
1558 	int min_stripes = 1, num_stripes = 1;
1559 	int i = 0, nr_devices;
1560 	int ret;
1561 
1562 	nr_devices = fs_info->fs_devices->open_devices;
1563 	BUG_ON(!nr_devices);
1564 
1565 	devices_info = kmalloc_array(nr_devices, sizeof(*devices_info),
1566 			       GFP_NOFS);
1567 	if (!devices_info)
1568 		return -ENOMEM;
1569 
1570 	/* calc min stripe number for data space alloction */
1571 	type = btrfs_get_alloc_profile(root, 1);
1572 	if (type & BTRFS_BLOCK_GROUP_RAID0) {
1573 		min_stripes = 2;
1574 		num_stripes = nr_devices;
1575 	} else if (type & BTRFS_BLOCK_GROUP_RAID1) {
1576 		min_stripes = 2;
1577 		num_stripes = 2;
1578 	} else if (type & BTRFS_BLOCK_GROUP_RAID10) {
1579 		min_stripes = 4;
1580 		num_stripes = 4;
1581 	}
1582 
1583 	if (type & BTRFS_BLOCK_GROUP_DUP)
1584 		min_stripe_size = 2 * BTRFS_STRIPE_LEN;
1585 	else
1586 		min_stripe_size = BTRFS_STRIPE_LEN;
1587 
1588 	list_for_each_entry(device, &fs_devices->devices, dev_list) {
1589 		if (!device->in_fs_metadata || !device->bdev ||
1590 		    device->is_tgtdev_for_dev_replace)
1591 			continue;
1592 
1593 		avail_space = device->total_bytes - device->bytes_used;
1594 
1595 		/* align with stripe_len */
1596 		do_div(avail_space, BTRFS_STRIPE_LEN);
1597 		avail_space *= BTRFS_STRIPE_LEN;
1598 
1599 		/*
1600 		 * In order to avoid overwritting the superblock on the drive,
1601 		 * btrfs starts at an offset of at least 1MB when doing chunk
1602 		 * allocation.
1603 		 */
1604 		skip_space = 1024 * 1024;
1605 
1606 		/* user can set the offset in fs_info->alloc_start. */
1607 		if (fs_info->alloc_start + BTRFS_STRIPE_LEN <=
1608 		    device->total_bytes)
1609 			skip_space = max(fs_info->alloc_start, skip_space);
1610 
1611 		/*
1612 		 * btrfs can not use the free space in [0, skip_space - 1],
1613 		 * we must subtract it from the total. In order to implement
1614 		 * it, we account the used space in this range first.
1615 		 */
1616 		ret = btrfs_account_dev_extents_size(device, 0, skip_space - 1,
1617 						     &used_space);
1618 		if (ret) {
1619 			kfree(devices_info);
1620 			return ret;
1621 		}
1622 
1623 		/* calc the free space in [0, skip_space - 1] */
1624 		skip_space -= used_space;
1625 
1626 		/*
1627 		 * we can use the free space in [0, skip_space - 1], subtract
1628 		 * it from the total.
1629 		 */
1630 		if (avail_space && avail_space >= skip_space)
1631 			avail_space -= skip_space;
1632 		else
1633 			avail_space = 0;
1634 
1635 		if (avail_space < min_stripe_size)
1636 			continue;
1637 
1638 		devices_info[i].dev = device;
1639 		devices_info[i].max_avail = avail_space;
1640 
1641 		i++;
1642 	}
1643 
1644 	nr_devices = i;
1645 
1646 	btrfs_descending_sort_devices(devices_info, nr_devices);
1647 
1648 	i = nr_devices - 1;
1649 	avail_space = 0;
1650 	while (nr_devices >= min_stripes) {
1651 		if (num_stripes > nr_devices)
1652 			num_stripes = nr_devices;
1653 
1654 		if (devices_info[i].max_avail >= min_stripe_size) {
1655 			int j;
1656 			u64 alloc_size;
1657 
1658 			avail_space += devices_info[i].max_avail * num_stripes;
1659 			alloc_size = devices_info[i].max_avail;
1660 			for (j = i + 1 - num_stripes; j <= i; j++)
1661 				devices_info[j].max_avail -= alloc_size;
1662 		}
1663 		i--;
1664 		nr_devices--;
1665 	}
1666 
1667 	kfree(devices_info);
1668 	*free_bytes = avail_space;
1669 	return 0;
1670 }
1671 
1672 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
1673 {
1674 	struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
1675 	struct btrfs_super_block *disk_super = fs_info->super_copy;
1676 	struct list_head *head = &fs_info->space_info;
1677 	struct btrfs_space_info *found;
1678 	u64 total_used = 0;
1679 	u64 total_free_data = 0;
1680 	int bits = dentry->d_sb->s_blocksize_bits;
1681 	__be32 *fsid = (__be32 *)fs_info->fsid;
1682 	int ret;
1683 
1684 	/* holding chunk_muext to avoid allocating new chunks */
1685 	mutex_lock(&fs_info->chunk_mutex);
1686 	rcu_read_lock();
1687 	list_for_each_entry_rcu(found, head, list) {
1688 		if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
1689 			total_free_data += found->disk_total - found->disk_used;
1690 			total_free_data -=
1691 				btrfs_account_ro_block_groups_free_space(found);
1692 		}
1693 
1694 		total_used += found->disk_used;
1695 	}
1696 	rcu_read_unlock();
1697 
1698 	buf->f_namelen = BTRFS_NAME_LEN;
1699 	buf->f_blocks = btrfs_super_total_bytes(disk_super) >> bits;
1700 	buf->f_bfree = buf->f_blocks - (total_used >> bits);
1701 	buf->f_bsize = dentry->d_sb->s_blocksize;
1702 	buf->f_type = BTRFS_SUPER_MAGIC;
1703 	buf->f_bavail = total_free_data;
1704 	ret = btrfs_calc_avail_data_space(fs_info->tree_root, &total_free_data);
1705 	if (ret) {
1706 		mutex_unlock(&fs_info->chunk_mutex);
1707 		return ret;
1708 	}
1709 	buf->f_bavail += total_free_data;
1710 	buf->f_bavail = buf->f_bavail >> bits;
1711 	mutex_unlock(&fs_info->chunk_mutex);
1712 
1713 	/* We treat it as constant endianness (it doesn't matter _which_)
1714 	   because we want the fsid to come out the same whether mounted
1715 	   on a big-endian or little-endian host */
1716 	buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
1717 	buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
1718 	/* Mask in the root object ID too, to disambiguate subvols */
1719 	buf->f_fsid.val[0] ^= BTRFS_I(dentry->d_inode)->root->objectid >> 32;
1720 	buf->f_fsid.val[1] ^= BTRFS_I(dentry->d_inode)->root->objectid;
1721 
1722 	return 0;
1723 }
1724 
1725 static void btrfs_kill_super(struct super_block *sb)
1726 {
1727 	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1728 	kill_anon_super(sb);
1729 	free_fs_info(fs_info);
1730 }
1731 
1732 static struct file_system_type btrfs_fs_type = {
1733 	.owner		= THIS_MODULE,
1734 	.name		= "btrfs",
1735 	.mount		= btrfs_mount,
1736 	.kill_sb	= btrfs_kill_super,
1737 	.fs_flags	= FS_REQUIRES_DEV,
1738 };
1739 MODULE_ALIAS_FS("btrfs");
1740 
1741 /*
1742  * used by btrfsctl to scan devices when no FS is mounted
1743  */
1744 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
1745 				unsigned long arg)
1746 {
1747 	struct btrfs_ioctl_vol_args *vol;
1748 	struct btrfs_fs_devices *fs_devices;
1749 	int ret = -ENOTTY;
1750 
1751 	if (!capable(CAP_SYS_ADMIN))
1752 		return -EPERM;
1753 
1754 	vol = memdup_user((void __user *)arg, sizeof(*vol));
1755 	if (IS_ERR(vol))
1756 		return PTR_ERR(vol);
1757 
1758 	switch (cmd) {
1759 	case BTRFS_IOC_SCAN_DEV:
1760 		ret = btrfs_scan_one_device(vol->name, FMODE_READ,
1761 					    &btrfs_fs_type, &fs_devices);
1762 		break;
1763 	case BTRFS_IOC_DEVICES_READY:
1764 		ret = btrfs_scan_one_device(vol->name, FMODE_READ,
1765 					    &btrfs_fs_type, &fs_devices);
1766 		if (ret)
1767 			break;
1768 		ret = !(fs_devices->num_devices == fs_devices->total_devices);
1769 		break;
1770 	}
1771 
1772 	kfree(vol);
1773 	return ret;
1774 }
1775 
1776 static int btrfs_freeze(struct super_block *sb)
1777 {
1778 	struct btrfs_trans_handle *trans;
1779 	struct btrfs_root *root = btrfs_sb(sb)->tree_root;
1780 
1781 	trans = btrfs_attach_transaction_barrier(root);
1782 	if (IS_ERR(trans)) {
1783 		/* no transaction, don't bother */
1784 		if (PTR_ERR(trans) == -ENOENT)
1785 			return 0;
1786 		return PTR_ERR(trans);
1787 	}
1788 	return btrfs_commit_transaction(trans, root);
1789 }
1790 
1791 static int btrfs_unfreeze(struct super_block *sb)
1792 {
1793 	return 0;
1794 }
1795 
1796 static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
1797 {
1798 	struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
1799 	struct btrfs_fs_devices *cur_devices;
1800 	struct btrfs_device *dev, *first_dev = NULL;
1801 	struct list_head *head;
1802 	struct rcu_string *name;
1803 
1804 	mutex_lock(&fs_info->fs_devices->device_list_mutex);
1805 	cur_devices = fs_info->fs_devices;
1806 	while (cur_devices) {
1807 		head = &cur_devices->devices;
1808 		list_for_each_entry(dev, head, dev_list) {
1809 			if (dev->missing)
1810 				continue;
1811 			if (!first_dev || dev->devid < first_dev->devid)
1812 				first_dev = dev;
1813 		}
1814 		cur_devices = cur_devices->seed;
1815 	}
1816 
1817 	if (first_dev) {
1818 		rcu_read_lock();
1819 		name = rcu_dereference(first_dev->name);
1820 		seq_escape(m, name->str, " \t\n\\");
1821 		rcu_read_unlock();
1822 	} else {
1823 		WARN_ON(1);
1824 	}
1825 	mutex_unlock(&fs_info->fs_devices->device_list_mutex);
1826 	return 0;
1827 }
1828 
1829 static const struct super_operations btrfs_super_ops = {
1830 	.drop_inode	= btrfs_drop_inode,
1831 	.evict_inode	= btrfs_evict_inode,
1832 	.put_super	= btrfs_put_super,
1833 	.sync_fs	= btrfs_sync_fs,
1834 	.show_options	= btrfs_show_options,
1835 	.show_devname	= btrfs_show_devname,
1836 	.write_inode	= btrfs_write_inode,
1837 	.alloc_inode	= btrfs_alloc_inode,
1838 	.destroy_inode	= btrfs_destroy_inode,
1839 	.statfs		= btrfs_statfs,
1840 	.remount_fs	= btrfs_remount,
1841 	.freeze_fs	= btrfs_freeze,
1842 	.unfreeze_fs	= btrfs_unfreeze,
1843 };
1844 
1845 static const struct file_operations btrfs_ctl_fops = {
1846 	.unlocked_ioctl	 = btrfs_control_ioctl,
1847 	.compat_ioctl = btrfs_control_ioctl,
1848 	.owner	 = THIS_MODULE,
1849 	.llseek = noop_llseek,
1850 };
1851 
1852 static struct miscdevice btrfs_misc = {
1853 	.minor		= BTRFS_MINOR,
1854 	.name		= "btrfs-control",
1855 	.fops		= &btrfs_ctl_fops
1856 };
1857 
1858 MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
1859 MODULE_ALIAS("devname:btrfs-control");
1860 
1861 static int btrfs_interface_init(void)
1862 {
1863 	return misc_register(&btrfs_misc);
1864 }
1865 
1866 static void btrfs_interface_exit(void)
1867 {
1868 	if (misc_deregister(&btrfs_misc) < 0)
1869 		printk(KERN_INFO "BTRFS: misc_deregister failed for control device\n");
1870 }
1871 
1872 static void btrfs_print_info(void)
1873 {
1874 	printk(KERN_INFO "Btrfs loaded"
1875 #ifdef CONFIG_BTRFS_DEBUG
1876 			", debug=on"
1877 #endif
1878 #ifdef CONFIG_BTRFS_ASSERT
1879 			", assert=on"
1880 #endif
1881 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
1882 			", integrity-checker=on"
1883 #endif
1884 			"\n");
1885 }
1886 
1887 static int btrfs_run_sanity_tests(void)
1888 {
1889 	int ret;
1890 
1891 	ret = btrfs_init_test_fs();
1892 	if (ret)
1893 		return ret;
1894 
1895 	ret = btrfs_test_free_space_cache();
1896 	if (ret)
1897 		goto out;
1898 	ret = btrfs_test_extent_buffer_operations();
1899 	if (ret)
1900 		goto out;
1901 	ret = btrfs_test_extent_io();
1902 	if (ret)
1903 		goto out;
1904 	ret = btrfs_test_inodes();
1905 	if (ret)
1906 		goto out;
1907 	ret = btrfs_test_qgroups();
1908 out:
1909 	btrfs_destroy_test_fs();
1910 	return ret;
1911 }
1912 
1913 static int __init init_btrfs_fs(void)
1914 {
1915 	int err;
1916 
1917 	err = btrfs_hash_init();
1918 	if (err)
1919 		return err;
1920 
1921 	btrfs_props_init();
1922 
1923 	err = btrfs_init_sysfs();
1924 	if (err)
1925 		goto free_hash;
1926 
1927 	btrfs_init_compress();
1928 
1929 	err = btrfs_init_cachep();
1930 	if (err)
1931 		goto free_compress;
1932 
1933 	err = extent_io_init();
1934 	if (err)
1935 		goto free_cachep;
1936 
1937 	err = extent_map_init();
1938 	if (err)
1939 		goto free_extent_io;
1940 
1941 	err = ordered_data_init();
1942 	if (err)
1943 		goto free_extent_map;
1944 
1945 	err = btrfs_delayed_inode_init();
1946 	if (err)
1947 		goto free_ordered_data;
1948 
1949 	err = btrfs_auto_defrag_init();
1950 	if (err)
1951 		goto free_delayed_inode;
1952 
1953 	err = btrfs_delayed_ref_init();
1954 	if (err)
1955 		goto free_auto_defrag;
1956 
1957 	err = btrfs_prelim_ref_init();
1958 	if (err)
1959 		goto free_prelim_ref;
1960 
1961 	err = btrfs_interface_init();
1962 	if (err)
1963 		goto free_delayed_ref;
1964 
1965 	btrfs_init_lockdep();
1966 
1967 	btrfs_print_info();
1968 
1969 	err = btrfs_run_sanity_tests();
1970 	if (err)
1971 		goto unregister_ioctl;
1972 
1973 	err = register_filesystem(&btrfs_fs_type);
1974 	if (err)
1975 		goto unregister_ioctl;
1976 
1977 	return 0;
1978 
1979 unregister_ioctl:
1980 	btrfs_interface_exit();
1981 free_prelim_ref:
1982 	btrfs_prelim_ref_exit();
1983 free_delayed_ref:
1984 	btrfs_delayed_ref_exit();
1985 free_auto_defrag:
1986 	btrfs_auto_defrag_exit();
1987 free_delayed_inode:
1988 	btrfs_delayed_inode_exit();
1989 free_ordered_data:
1990 	ordered_data_exit();
1991 free_extent_map:
1992 	extent_map_exit();
1993 free_extent_io:
1994 	extent_io_exit();
1995 free_cachep:
1996 	btrfs_destroy_cachep();
1997 free_compress:
1998 	btrfs_exit_compress();
1999 	btrfs_exit_sysfs();
2000 free_hash:
2001 	btrfs_hash_exit();
2002 	return err;
2003 }
2004 
2005 static void __exit exit_btrfs_fs(void)
2006 {
2007 	btrfs_destroy_cachep();
2008 	btrfs_delayed_ref_exit();
2009 	btrfs_auto_defrag_exit();
2010 	btrfs_delayed_inode_exit();
2011 	btrfs_prelim_ref_exit();
2012 	ordered_data_exit();
2013 	extent_map_exit();
2014 	extent_io_exit();
2015 	btrfs_interface_exit();
2016 	unregister_filesystem(&btrfs_fs_type);
2017 	btrfs_exit_sysfs();
2018 	btrfs_cleanup_fs_uuids();
2019 	btrfs_exit_compress();
2020 	btrfs_hash_exit();
2021 }
2022 
2023 late_initcall(init_btrfs_fs);
2024 module_exit(exit_btrfs_fs)
2025 
2026 MODULE_LICENSE("GPL");
2027