xref: /linux/fs/btrfs/super.c (revision ec2212088c42ff7d1362629ec26dda4f3e8bdad3)
1 /*
2  * Copyright (C) 2007 Oracle.  All rights reserved.
3  *
4  * This program is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU General Public
6  * License v2 as published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope that it will be useful,
9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
11  * General Public License for more details.
12  *
13  * You should have received a copy of the GNU General Public
14  * License along with this program; if not, write to the
15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16  * Boston, MA 021110-1307, USA.
17  */
18 
19 #include <linux/blkdev.h>
20 #include <linux/module.h>
21 #include <linux/buffer_head.h>
22 #include <linux/fs.h>
23 #include <linux/pagemap.h>
24 #include <linux/highmem.h>
25 #include <linux/time.h>
26 #include <linux/init.h>
27 #include <linux/seq_file.h>
28 #include <linux/string.h>
29 #include <linux/backing-dev.h>
30 #include <linux/mount.h>
31 #include <linux/mpage.h>
32 #include <linux/swap.h>
33 #include <linux/writeback.h>
34 #include <linux/statfs.h>
35 #include <linux/compat.h>
36 #include <linux/parser.h>
37 #include <linux/ctype.h>
38 #include <linux/namei.h>
39 #include <linux/miscdevice.h>
40 #include <linux/magic.h>
41 #include <linux/slab.h>
42 #include <linux/cleancache.h>
43 #include <linux/ratelimit.h>
44 #include "compat.h"
45 #include "delayed-inode.h"
46 #include "ctree.h"
47 #include "disk-io.h"
48 #include "transaction.h"
49 #include "btrfs_inode.h"
50 #include "ioctl.h"
51 #include "print-tree.h"
52 #include "xattr.h"
53 #include "volumes.h"
54 #include "version.h"
55 #include "export.h"
56 #include "compression.h"
57 
58 #define CREATE_TRACE_POINTS
59 #include <trace/events/btrfs.h>
60 
61 static const struct super_operations btrfs_super_ops;
62 static struct file_system_type btrfs_fs_type;
63 
64 static const char *btrfs_decode_error(struct btrfs_fs_info *fs_info, int errno,
65 				      char nbuf[16])
66 {
67 	char *errstr = NULL;
68 
69 	switch (errno) {
70 	case -EIO:
71 		errstr = "IO failure";
72 		break;
73 	case -ENOMEM:
74 		errstr = "Out of memory";
75 		break;
76 	case -EROFS:
77 		errstr = "Readonly filesystem";
78 		break;
79 	default:
80 		if (nbuf) {
81 			if (snprintf(nbuf, 16, "error %d", -errno) >= 0)
82 				errstr = nbuf;
83 		}
84 		break;
85 	}
86 
87 	return errstr;
88 }
89 
90 static void __save_error_info(struct btrfs_fs_info *fs_info)
91 {
92 	/*
93 	 * today we only save the error info into ram.  Long term we'll
94 	 * also send it down to the disk
95 	 */
96 	fs_info->fs_state = BTRFS_SUPER_FLAG_ERROR;
97 }
98 
99 /* NOTE:
100  *	We move write_super stuff at umount in order to avoid deadlock
101  *	for umount hold all lock.
102  */
103 static void save_error_info(struct btrfs_fs_info *fs_info)
104 {
105 	__save_error_info(fs_info);
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 (fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
117 		sb->s_flags |= MS_RDONLY;
118 		printk(KERN_INFO "btrfs is forced readonly\n");
119 	}
120 }
121 
122 /*
123  * __btrfs_std_error decodes expected errors from the caller and
124  * invokes the approciate error response.
125  */
126 void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function,
127 		     unsigned int line, int errno)
128 {
129 	struct super_block *sb = fs_info->sb;
130 	char nbuf[16];
131 	const char *errstr;
132 
133 	/*
134 	 * Special case: if the error is EROFS, and we're already
135 	 * under MS_RDONLY, then it is safe here.
136 	 */
137 	if (errno == -EROFS && (sb->s_flags & MS_RDONLY))
138 		return;
139 
140 	errstr = btrfs_decode_error(fs_info, errno, nbuf);
141 	printk(KERN_CRIT "BTRFS error (device %s) in %s:%d: %s\n",
142 		sb->s_id, function, line, errstr);
143 	save_error_info(fs_info);
144 
145 	btrfs_handle_error(fs_info);
146 }
147 
148 static void btrfs_put_super(struct super_block *sb)
149 {
150 	(void)close_ctree(btrfs_sb(sb)->tree_root);
151 	/* FIXME: need to fix VFS to return error? */
152 	/* AV: return it _where_?  ->put_super() can be triggered by any number
153 	 * of async events, up to and including delivery of SIGKILL to the
154 	 * last process that kept it busy.  Or segfault in the aforementioned
155 	 * process...  Whom would you report that to?
156 	 */
157 }
158 
159 enum {
160 	Opt_degraded, Opt_subvol, Opt_subvolid, Opt_device, Opt_nodatasum,
161 	Opt_nodatacow, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd,
162 	Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl, Opt_compress,
163 	Opt_compress_type, Opt_compress_force, Opt_compress_force_type,
164 	Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard,
165 	Opt_space_cache, Opt_clear_cache, Opt_user_subvol_rm_allowed,
166 	Opt_enospc_debug, Opt_subvolrootid, Opt_defrag, Opt_inode_cache,
167 	Opt_no_space_cache, Opt_recovery, Opt_skip_balance,
168 	Opt_check_integrity, Opt_check_integrity_including_extent_data,
169 	Opt_check_integrity_print_mask,
170 	Opt_err,
171 };
172 
173 static match_table_t tokens = {
174 	{Opt_degraded, "degraded"},
175 	{Opt_subvol, "subvol=%s"},
176 	{Opt_subvolid, "subvolid=%d"},
177 	{Opt_device, "device=%s"},
178 	{Opt_nodatasum, "nodatasum"},
179 	{Opt_nodatacow, "nodatacow"},
180 	{Opt_nobarrier, "nobarrier"},
181 	{Opt_max_inline, "max_inline=%s"},
182 	{Opt_alloc_start, "alloc_start=%s"},
183 	{Opt_thread_pool, "thread_pool=%d"},
184 	{Opt_compress, "compress"},
185 	{Opt_compress_type, "compress=%s"},
186 	{Opt_compress_force, "compress-force"},
187 	{Opt_compress_force_type, "compress-force=%s"},
188 	{Opt_ssd, "ssd"},
189 	{Opt_ssd_spread, "ssd_spread"},
190 	{Opt_nossd, "nossd"},
191 	{Opt_noacl, "noacl"},
192 	{Opt_notreelog, "notreelog"},
193 	{Opt_flushoncommit, "flushoncommit"},
194 	{Opt_ratio, "metadata_ratio=%d"},
195 	{Opt_discard, "discard"},
196 	{Opt_space_cache, "space_cache"},
197 	{Opt_clear_cache, "clear_cache"},
198 	{Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
199 	{Opt_enospc_debug, "enospc_debug"},
200 	{Opt_subvolrootid, "subvolrootid=%d"},
201 	{Opt_defrag, "autodefrag"},
202 	{Opt_inode_cache, "inode_cache"},
203 	{Opt_no_space_cache, "nospace_cache"},
204 	{Opt_recovery, "recovery"},
205 	{Opt_skip_balance, "skip_balance"},
206 	{Opt_check_integrity, "check_int"},
207 	{Opt_check_integrity_including_extent_data, "check_int_data"},
208 	{Opt_check_integrity_print_mask, "check_int_print_mask=%d"},
209 	{Opt_err, NULL},
210 };
211 
212 /*
213  * Regular mount options parser.  Everything that is needed only when
214  * reading in a new superblock is parsed here.
215  */
216 int btrfs_parse_options(struct btrfs_root *root, char *options)
217 {
218 	struct btrfs_fs_info *info = root->fs_info;
219 	substring_t args[MAX_OPT_ARGS];
220 	char *p, *num, *orig = NULL;
221 	u64 cache_gen;
222 	int intarg;
223 	int ret = 0;
224 	char *compress_type;
225 	bool compress_force = false;
226 
227 	cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
228 	if (cache_gen)
229 		btrfs_set_opt(info->mount_opt, SPACE_CACHE);
230 
231 	if (!options)
232 		goto out;
233 
234 	/*
235 	 * strsep changes the string, duplicate it because parse_options
236 	 * gets called twice
237 	 */
238 	options = kstrdup(options, GFP_NOFS);
239 	if (!options)
240 		return -ENOMEM;
241 
242 	orig = options;
243 
244 	while ((p = strsep(&options, ",")) != NULL) {
245 		int token;
246 		if (!*p)
247 			continue;
248 
249 		token = match_token(p, tokens, args);
250 		switch (token) {
251 		case Opt_degraded:
252 			printk(KERN_INFO "btrfs: allowing degraded mounts\n");
253 			btrfs_set_opt(info->mount_opt, DEGRADED);
254 			break;
255 		case Opt_subvol:
256 		case Opt_subvolid:
257 		case Opt_subvolrootid:
258 		case Opt_device:
259 			/*
260 			 * These are parsed by btrfs_parse_early_options
261 			 * and can be happily ignored here.
262 			 */
263 			break;
264 		case Opt_nodatasum:
265 			printk(KERN_INFO "btrfs: setting nodatasum\n");
266 			btrfs_set_opt(info->mount_opt, NODATASUM);
267 			break;
268 		case Opt_nodatacow:
269 			printk(KERN_INFO "btrfs: setting nodatacow\n");
270 			btrfs_set_opt(info->mount_opt, NODATACOW);
271 			btrfs_set_opt(info->mount_opt, NODATASUM);
272 			break;
273 		case Opt_compress_force:
274 		case Opt_compress_force_type:
275 			compress_force = true;
276 		case Opt_compress:
277 		case Opt_compress_type:
278 			if (token == Opt_compress ||
279 			    token == Opt_compress_force ||
280 			    strcmp(args[0].from, "zlib") == 0) {
281 				compress_type = "zlib";
282 				info->compress_type = BTRFS_COMPRESS_ZLIB;
283 			} else if (strcmp(args[0].from, "lzo") == 0) {
284 				compress_type = "lzo";
285 				info->compress_type = BTRFS_COMPRESS_LZO;
286 			} else {
287 				ret = -EINVAL;
288 				goto out;
289 			}
290 
291 			btrfs_set_opt(info->mount_opt, COMPRESS);
292 			if (compress_force) {
293 				btrfs_set_opt(info->mount_opt, FORCE_COMPRESS);
294 				pr_info("btrfs: force %s compression\n",
295 					compress_type);
296 			} else
297 				pr_info("btrfs: use %s compression\n",
298 					compress_type);
299 			break;
300 		case Opt_ssd:
301 			printk(KERN_INFO "btrfs: use ssd allocation scheme\n");
302 			btrfs_set_opt(info->mount_opt, SSD);
303 			break;
304 		case Opt_ssd_spread:
305 			printk(KERN_INFO "btrfs: use spread ssd "
306 			       "allocation scheme\n");
307 			btrfs_set_opt(info->mount_opt, SSD);
308 			btrfs_set_opt(info->mount_opt, SSD_SPREAD);
309 			break;
310 		case Opt_nossd:
311 			printk(KERN_INFO "btrfs: not using ssd allocation "
312 			       "scheme\n");
313 			btrfs_set_opt(info->mount_opt, NOSSD);
314 			btrfs_clear_opt(info->mount_opt, SSD);
315 			btrfs_clear_opt(info->mount_opt, SSD_SPREAD);
316 			break;
317 		case Opt_nobarrier:
318 			printk(KERN_INFO "btrfs: turning off barriers\n");
319 			btrfs_set_opt(info->mount_opt, NOBARRIER);
320 			break;
321 		case Opt_thread_pool:
322 			intarg = 0;
323 			match_int(&args[0], &intarg);
324 			if (intarg) {
325 				info->thread_pool_size = intarg;
326 				printk(KERN_INFO "btrfs: thread pool %d\n",
327 				       info->thread_pool_size);
328 			}
329 			break;
330 		case Opt_max_inline:
331 			num = match_strdup(&args[0]);
332 			if (num) {
333 				info->max_inline = memparse(num, NULL);
334 				kfree(num);
335 
336 				if (info->max_inline) {
337 					info->max_inline = max_t(u64,
338 						info->max_inline,
339 						root->sectorsize);
340 				}
341 				printk(KERN_INFO "btrfs: max_inline at %llu\n",
342 					(unsigned long long)info->max_inline);
343 			}
344 			break;
345 		case Opt_alloc_start:
346 			num = match_strdup(&args[0]);
347 			if (num) {
348 				info->alloc_start = memparse(num, NULL);
349 				kfree(num);
350 				printk(KERN_INFO
351 					"btrfs: allocations start at %llu\n",
352 					(unsigned long long)info->alloc_start);
353 			}
354 			break;
355 		case Opt_noacl:
356 			root->fs_info->sb->s_flags &= ~MS_POSIXACL;
357 			break;
358 		case Opt_notreelog:
359 			printk(KERN_INFO "btrfs: disabling tree log\n");
360 			btrfs_set_opt(info->mount_opt, NOTREELOG);
361 			break;
362 		case Opt_flushoncommit:
363 			printk(KERN_INFO "btrfs: turning on flush-on-commit\n");
364 			btrfs_set_opt(info->mount_opt, FLUSHONCOMMIT);
365 			break;
366 		case Opt_ratio:
367 			intarg = 0;
368 			match_int(&args[0], &intarg);
369 			if (intarg) {
370 				info->metadata_ratio = intarg;
371 				printk(KERN_INFO "btrfs: metadata ratio %d\n",
372 				       info->metadata_ratio);
373 			}
374 			break;
375 		case Opt_discard:
376 			btrfs_set_opt(info->mount_opt, DISCARD);
377 			break;
378 		case Opt_space_cache:
379 			btrfs_set_opt(info->mount_opt, SPACE_CACHE);
380 			break;
381 		case Opt_no_space_cache:
382 			printk(KERN_INFO "btrfs: disabling disk space caching\n");
383 			btrfs_clear_opt(info->mount_opt, SPACE_CACHE);
384 			break;
385 		case Opt_inode_cache:
386 			printk(KERN_INFO "btrfs: enabling inode map caching\n");
387 			btrfs_set_opt(info->mount_opt, INODE_MAP_CACHE);
388 			break;
389 		case Opt_clear_cache:
390 			printk(KERN_INFO "btrfs: force clearing of disk cache\n");
391 			btrfs_set_opt(info->mount_opt, CLEAR_CACHE);
392 			break;
393 		case Opt_user_subvol_rm_allowed:
394 			btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
395 			break;
396 		case Opt_enospc_debug:
397 			btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
398 			break;
399 		case Opt_defrag:
400 			printk(KERN_INFO "btrfs: enabling auto defrag");
401 			btrfs_set_opt(info->mount_opt, AUTO_DEFRAG);
402 			break;
403 		case Opt_recovery:
404 			printk(KERN_INFO "btrfs: enabling auto recovery");
405 			btrfs_set_opt(info->mount_opt, RECOVERY);
406 			break;
407 		case Opt_skip_balance:
408 			btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
409 			break;
410 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
411 		case Opt_check_integrity_including_extent_data:
412 			printk(KERN_INFO "btrfs: enabling check integrity"
413 			       " including extent data\n");
414 			btrfs_set_opt(info->mount_opt,
415 				      CHECK_INTEGRITY_INCLUDING_EXTENT_DATA);
416 			btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
417 			break;
418 		case Opt_check_integrity:
419 			printk(KERN_INFO "btrfs: enabling check integrity\n");
420 			btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
421 			break;
422 		case Opt_check_integrity_print_mask:
423 			intarg = 0;
424 			match_int(&args[0], &intarg);
425 			if (intarg) {
426 				info->check_integrity_print_mask = intarg;
427 				printk(KERN_INFO "btrfs:"
428 				       " check_integrity_print_mask 0x%x\n",
429 				       info->check_integrity_print_mask);
430 			}
431 			break;
432 #else
433 		case Opt_check_integrity_including_extent_data:
434 		case Opt_check_integrity:
435 		case Opt_check_integrity_print_mask:
436 			printk(KERN_ERR "btrfs: support for check_integrity*"
437 			       " not compiled in!\n");
438 			ret = -EINVAL;
439 			goto out;
440 #endif
441 		case Opt_err:
442 			printk(KERN_INFO "btrfs: unrecognized mount option "
443 			       "'%s'\n", p);
444 			ret = -EINVAL;
445 			goto out;
446 		default:
447 			break;
448 		}
449 	}
450 out:
451 	if (!ret && btrfs_test_opt(root, SPACE_CACHE))
452 		printk(KERN_INFO "btrfs: disk space caching is enabled\n");
453 	kfree(orig);
454 	return ret;
455 }
456 
457 /*
458  * Parse mount options that are required early in the mount process.
459  *
460  * All other options will be parsed on much later in the mount process and
461  * only when we need to allocate a new super block.
462  */
463 static int btrfs_parse_early_options(const char *options, fmode_t flags,
464 		void *holder, char **subvol_name, u64 *subvol_objectid,
465 		u64 *subvol_rootid, struct btrfs_fs_devices **fs_devices)
466 {
467 	substring_t args[MAX_OPT_ARGS];
468 	char *device_name, *opts, *orig, *p;
469 	int error = 0;
470 	int intarg;
471 
472 	if (!options)
473 		return 0;
474 
475 	/*
476 	 * strsep changes the string, duplicate it because parse_options
477 	 * gets called twice
478 	 */
479 	opts = kstrdup(options, GFP_KERNEL);
480 	if (!opts)
481 		return -ENOMEM;
482 	orig = opts;
483 
484 	while ((p = strsep(&opts, ",")) != NULL) {
485 		int token;
486 		if (!*p)
487 			continue;
488 
489 		token = match_token(p, tokens, args);
490 		switch (token) {
491 		case Opt_subvol:
492 			kfree(*subvol_name);
493 			*subvol_name = match_strdup(&args[0]);
494 			break;
495 		case Opt_subvolid:
496 			intarg = 0;
497 			error = match_int(&args[0], &intarg);
498 			if (!error) {
499 				/* we want the original fs_tree */
500 				if (!intarg)
501 					*subvol_objectid =
502 						BTRFS_FS_TREE_OBJECTID;
503 				else
504 					*subvol_objectid = intarg;
505 			}
506 			break;
507 		case Opt_subvolrootid:
508 			intarg = 0;
509 			error = match_int(&args[0], &intarg);
510 			if (!error) {
511 				/* we want the original fs_tree */
512 				if (!intarg)
513 					*subvol_rootid =
514 						BTRFS_FS_TREE_OBJECTID;
515 				else
516 					*subvol_rootid = intarg;
517 			}
518 			break;
519 		case Opt_device:
520 			device_name = match_strdup(&args[0]);
521 			if (!device_name) {
522 				error = -ENOMEM;
523 				goto out;
524 			}
525 			error = btrfs_scan_one_device(device_name,
526 					flags, holder, fs_devices);
527 			kfree(device_name);
528 			if (error)
529 				goto out;
530 			break;
531 		default:
532 			break;
533 		}
534 	}
535 
536 out:
537 	kfree(orig);
538 	return error;
539 }
540 
541 static struct dentry *get_default_root(struct super_block *sb,
542 				       u64 subvol_objectid)
543 {
544 	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
545 	struct btrfs_root *root = fs_info->tree_root;
546 	struct btrfs_root *new_root;
547 	struct btrfs_dir_item *di;
548 	struct btrfs_path *path;
549 	struct btrfs_key location;
550 	struct inode *inode;
551 	u64 dir_id;
552 	int new = 0;
553 
554 	/*
555 	 * We have a specific subvol we want to mount, just setup location and
556 	 * go look up the root.
557 	 */
558 	if (subvol_objectid) {
559 		location.objectid = subvol_objectid;
560 		location.type = BTRFS_ROOT_ITEM_KEY;
561 		location.offset = (u64)-1;
562 		goto find_root;
563 	}
564 
565 	path = btrfs_alloc_path();
566 	if (!path)
567 		return ERR_PTR(-ENOMEM);
568 	path->leave_spinning = 1;
569 
570 	/*
571 	 * Find the "default" dir item which points to the root item that we
572 	 * will mount by default if we haven't been given a specific subvolume
573 	 * to mount.
574 	 */
575 	dir_id = btrfs_super_root_dir(fs_info->super_copy);
576 	di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
577 	if (IS_ERR(di)) {
578 		btrfs_free_path(path);
579 		return ERR_CAST(di);
580 	}
581 	if (!di) {
582 		/*
583 		 * Ok the default dir item isn't there.  This is weird since
584 		 * it's always been there, but don't freak out, just try and
585 		 * mount to root most subvolume.
586 		 */
587 		btrfs_free_path(path);
588 		dir_id = BTRFS_FIRST_FREE_OBJECTID;
589 		new_root = fs_info->fs_root;
590 		goto setup_root;
591 	}
592 
593 	btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
594 	btrfs_free_path(path);
595 
596 find_root:
597 	new_root = btrfs_read_fs_root_no_name(fs_info, &location);
598 	if (IS_ERR(new_root))
599 		return ERR_CAST(new_root);
600 
601 	if (btrfs_root_refs(&new_root->root_item) == 0)
602 		return ERR_PTR(-ENOENT);
603 
604 	dir_id = btrfs_root_dirid(&new_root->root_item);
605 setup_root:
606 	location.objectid = dir_id;
607 	location.type = BTRFS_INODE_ITEM_KEY;
608 	location.offset = 0;
609 
610 	inode = btrfs_iget(sb, &location, new_root, &new);
611 	if (IS_ERR(inode))
612 		return ERR_CAST(inode);
613 
614 	/*
615 	 * If we're just mounting the root most subvol put the inode and return
616 	 * a reference to the dentry.  We will have already gotten a reference
617 	 * to the inode in btrfs_fill_super so we're good to go.
618 	 */
619 	if (!new && sb->s_root->d_inode == inode) {
620 		iput(inode);
621 		return dget(sb->s_root);
622 	}
623 
624 	return d_obtain_alias(inode);
625 }
626 
627 static int btrfs_fill_super(struct super_block *sb,
628 			    struct btrfs_fs_devices *fs_devices,
629 			    void *data, int silent)
630 {
631 	struct inode *inode;
632 	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
633 	struct btrfs_key key;
634 	int err;
635 
636 	sb->s_maxbytes = MAX_LFS_FILESIZE;
637 	sb->s_magic = BTRFS_SUPER_MAGIC;
638 	sb->s_op = &btrfs_super_ops;
639 	sb->s_d_op = &btrfs_dentry_operations;
640 	sb->s_export_op = &btrfs_export_ops;
641 	sb->s_xattr = btrfs_xattr_handlers;
642 	sb->s_time_gran = 1;
643 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
644 	sb->s_flags |= MS_POSIXACL;
645 #endif
646 
647 	err = open_ctree(sb, fs_devices, (char *)data);
648 	if (err) {
649 		printk("btrfs: open_ctree failed\n");
650 		return err;
651 	}
652 
653 	key.objectid = BTRFS_FIRST_FREE_OBJECTID;
654 	key.type = BTRFS_INODE_ITEM_KEY;
655 	key.offset = 0;
656 	inode = btrfs_iget(sb, &key, fs_info->fs_root, NULL);
657 	if (IS_ERR(inode)) {
658 		err = PTR_ERR(inode);
659 		goto fail_close;
660 	}
661 
662 	sb->s_root = d_make_root(inode);
663 	if (!sb->s_root) {
664 		err = -ENOMEM;
665 		goto fail_close;
666 	}
667 
668 	save_mount_options(sb, data);
669 	cleancache_init_fs(sb);
670 	sb->s_flags |= MS_ACTIVE;
671 	return 0;
672 
673 fail_close:
674 	close_ctree(fs_info->tree_root);
675 	return err;
676 }
677 
678 int btrfs_sync_fs(struct super_block *sb, int wait)
679 {
680 	struct btrfs_trans_handle *trans;
681 	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
682 	struct btrfs_root *root = fs_info->tree_root;
683 	int ret;
684 
685 	trace_btrfs_sync_fs(wait);
686 
687 	if (!wait) {
688 		filemap_flush(fs_info->btree_inode->i_mapping);
689 		return 0;
690 	}
691 
692 	btrfs_start_delalloc_inodes(root, 0);
693 	btrfs_wait_ordered_extents(root, 0, 0);
694 
695 	trans = btrfs_start_transaction(root, 0);
696 	if (IS_ERR(trans))
697 		return PTR_ERR(trans);
698 	ret = btrfs_commit_transaction(trans, root);
699 	return ret;
700 }
701 
702 static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
703 {
704 	struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
705 	struct btrfs_root *root = info->tree_root;
706 	char *compress_type;
707 
708 	if (btrfs_test_opt(root, DEGRADED))
709 		seq_puts(seq, ",degraded");
710 	if (btrfs_test_opt(root, NODATASUM))
711 		seq_puts(seq, ",nodatasum");
712 	if (btrfs_test_opt(root, NODATACOW))
713 		seq_puts(seq, ",nodatacow");
714 	if (btrfs_test_opt(root, NOBARRIER))
715 		seq_puts(seq, ",nobarrier");
716 	if (info->max_inline != 8192 * 1024)
717 		seq_printf(seq, ",max_inline=%llu",
718 			   (unsigned long long)info->max_inline);
719 	if (info->alloc_start != 0)
720 		seq_printf(seq, ",alloc_start=%llu",
721 			   (unsigned long long)info->alloc_start);
722 	if (info->thread_pool_size !=  min_t(unsigned long,
723 					     num_online_cpus() + 2, 8))
724 		seq_printf(seq, ",thread_pool=%d", info->thread_pool_size);
725 	if (btrfs_test_opt(root, COMPRESS)) {
726 		if (info->compress_type == BTRFS_COMPRESS_ZLIB)
727 			compress_type = "zlib";
728 		else
729 			compress_type = "lzo";
730 		if (btrfs_test_opt(root, FORCE_COMPRESS))
731 			seq_printf(seq, ",compress-force=%s", compress_type);
732 		else
733 			seq_printf(seq, ",compress=%s", compress_type);
734 	}
735 	if (btrfs_test_opt(root, NOSSD))
736 		seq_puts(seq, ",nossd");
737 	if (btrfs_test_opt(root, SSD_SPREAD))
738 		seq_puts(seq, ",ssd_spread");
739 	else if (btrfs_test_opt(root, SSD))
740 		seq_puts(seq, ",ssd");
741 	if (btrfs_test_opt(root, NOTREELOG))
742 		seq_puts(seq, ",notreelog");
743 	if (btrfs_test_opt(root, FLUSHONCOMMIT))
744 		seq_puts(seq, ",flushoncommit");
745 	if (btrfs_test_opt(root, DISCARD))
746 		seq_puts(seq, ",discard");
747 	if (!(root->fs_info->sb->s_flags & MS_POSIXACL))
748 		seq_puts(seq, ",noacl");
749 	if (btrfs_test_opt(root, SPACE_CACHE))
750 		seq_puts(seq, ",space_cache");
751 	else
752 		seq_puts(seq, ",nospace_cache");
753 	if (btrfs_test_opt(root, CLEAR_CACHE))
754 		seq_puts(seq, ",clear_cache");
755 	if (btrfs_test_opt(root, USER_SUBVOL_RM_ALLOWED))
756 		seq_puts(seq, ",user_subvol_rm_allowed");
757 	if (btrfs_test_opt(root, ENOSPC_DEBUG))
758 		seq_puts(seq, ",enospc_debug");
759 	if (btrfs_test_opt(root, AUTO_DEFRAG))
760 		seq_puts(seq, ",autodefrag");
761 	if (btrfs_test_opt(root, INODE_MAP_CACHE))
762 		seq_puts(seq, ",inode_cache");
763 	if (btrfs_test_opt(root, SKIP_BALANCE))
764 		seq_puts(seq, ",skip_balance");
765 	return 0;
766 }
767 
768 static int btrfs_test_super(struct super_block *s, void *data)
769 {
770 	struct btrfs_fs_info *p = data;
771 	struct btrfs_fs_info *fs_info = btrfs_sb(s);
772 
773 	return fs_info->fs_devices == p->fs_devices;
774 }
775 
776 static int btrfs_set_super(struct super_block *s, void *data)
777 {
778 	int err = set_anon_super(s, data);
779 	if (!err)
780 		s->s_fs_info = data;
781 	return err;
782 }
783 
784 /*
785  * subvolumes are identified by ino 256
786  */
787 static inline int is_subvolume_inode(struct inode *inode)
788 {
789 	if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
790 		return 1;
791 	return 0;
792 }
793 
794 /*
795  * This will strip out the subvol=%s argument for an argument string and add
796  * subvolid=0 to make sure we get the actual tree root for path walking to the
797  * subvol we want.
798  */
799 static char *setup_root_args(char *args)
800 {
801 	unsigned copied = 0;
802 	unsigned len = strlen(args) + 2;
803 	char *pos;
804 	char *ret;
805 
806 	/*
807 	 * We need the same args as before, but minus
808 	 *
809 	 * subvol=a
810 	 *
811 	 * and add
812 	 *
813 	 * subvolid=0
814 	 *
815 	 * which is a difference of 2 characters, so we allocate strlen(args) +
816 	 * 2 characters.
817 	 */
818 	ret = kzalloc(len * sizeof(char), GFP_NOFS);
819 	if (!ret)
820 		return NULL;
821 	pos = strstr(args, "subvol=");
822 
823 	/* This shouldn't happen, but just in case.. */
824 	if (!pos) {
825 		kfree(ret);
826 		return NULL;
827 	}
828 
829 	/*
830 	 * The subvol=<> arg is not at the front of the string, copy everybody
831 	 * up to that into ret.
832 	 */
833 	if (pos != args) {
834 		*pos = '\0';
835 		strcpy(ret, args);
836 		copied += strlen(args);
837 		pos++;
838 	}
839 
840 	strncpy(ret + copied, "subvolid=0", len - copied);
841 
842 	/* Length of subvolid=0 */
843 	copied += 10;
844 
845 	/*
846 	 * If there is no , after the subvol= option then we know there's no
847 	 * other options and we can just return.
848 	 */
849 	pos = strchr(pos, ',');
850 	if (!pos)
851 		return ret;
852 
853 	/* Copy the rest of the arguments into our buffer */
854 	strncpy(ret + copied, pos, len - copied);
855 	copied += strlen(pos);
856 
857 	return ret;
858 }
859 
860 static struct dentry *mount_subvol(const char *subvol_name, int flags,
861 				   const char *device_name, char *data)
862 {
863 	struct dentry *root;
864 	struct vfsmount *mnt;
865 	char *newargs;
866 
867 	newargs = setup_root_args(data);
868 	if (!newargs)
869 		return ERR_PTR(-ENOMEM);
870 	mnt = vfs_kern_mount(&btrfs_fs_type, flags, device_name,
871 			     newargs);
872 	kfree(newargs);
873 	if (IS_ERR(mnt))
874 		return ERR_CAST(mnt);
875 
876 	root = mount_subtree(mnt, subvol_name);
877 
878 	if (!IS_ERR(root) && !is_subvolume_inode(root->d_inode)) {
879 		struct super_block *s = root->d_sb;
880 		dput(root);
881 		root = ERR_PTR(-EINVAL);
882 		deactivate_locked_super(s);
883 		printk(KERN_ERR "btrfs: '%s' is not a valid subvolume\n",
884 				subvol_name);
885 	}
886 
887 	return root;
888 }
889 
890 /*
891  * Find a superblock for the given device / mount point.
892  *
893  * Note:  This is based on get_sb_bdev from fs/super.c with a few additions
894  *	  for multiple device setup.  Make sure to keep it in sync.
895  */
896 static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
897 		const char *device_name, void *data)
898 {
899 	struct block_device *bdev = NULL;
900 	struct super_block *s;
901 	struct dentry *root;
902 	struct btrfs_fs_devices *fs_devices = NULL;
903 	struct btrfs_fs_info *fs_info = NULL;
904 	fmode_t mode = FMODE_READ;
905 	char *subvol_name = NULL;
906 	u64 subvol_objectid = 0;
907 	u64 subvol_rootid = 0;
908 	int error = 0;
909 
910 	if (!(flags & MS_RDONLY))
911 		mode |= FMODE_WRITE;
912 
913 	error = btrfs_parse_early_options(data, mode, fs_type,
914 					  &subvol_name, &subvol_objectid,
915 					  &subvol_rootid, &fs_devices);
916 	if (error) {
917 		kfree(subvol_name);
918 		return ERR_PTR(error);
919 	}
920 
921 	if (subvol_name) {
922 		root = mount_subvol(subvol_name, flags, device_name, data);
923 		kfree(subvol_name);
924 		return root;
925 	}
926 
927 	error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices);
928 	if (error)
929 		return ERR_PTR(error);
930 
931 	/*
932 	 * Setup a dummy root and fs_info for test/set super.  This is because
933 	 * we don't actually fill this stuff out until open_ctree, but we need
934 	 * it for searching for existing supers, so this lets us do that and
935 	 * then open_ctree will properly initialize everything later.
936 	 */
937 	fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_NOFS);
938 	if (!fs_info)
939 		return ERR_PTR(-ENOMEM);
940 
941 	fs_info->fs_devices = fs_devices;
942 
943 	fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
944 	fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
945 	if (!fs_info->super_copy || !fs_info->super_for_commit) {
946 		error = -ENOMEM;
947 		goto error_fs_info;
948 	}
949 
950 	error = btrfs_open_devices(fs_devices, mode, fs_type);
951 	if (error)
952 		goto error_fs_info;
953 
954 	if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
955 		error = -EACCES;
956 		goto error_close_devices;
957 	}
958 
959 	bdev = fs_devices->latest_bdev;
960 	s = sget(fs_type, btrfs_test_super, btrfs_set_super, fs_info);
961 	if (IS_ERR(s)) {
962 		error = PTR_ERR(s);
963 		goto error_close_devices;
964 	}
965 
966 	if (s->s_root) {
967 		btrfs_close_devices(fs_devices);
968 		free_fs_info(fs_info);
969 		if ((flags ^ s->s_flags) & MS_RDONLY)
970 			error = -EBUSY;
971 	} else {
972 		char b[BDEVNAME_SIZE];
973 
974 		s->s_flags = flags | MS_NOSEC;
975 		strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
976 		btrfs_sb(s)->bdev_holder = fs_type;
977 		error = btrfs_fill_super(s, fs_devices, data,
978 					 flags & MS_SILENT ? 1 : 0);
979 	}
980 
981 	root = !error ? get_default_root(s, subvol_objectid) : ERR_PTR(error);
982 	if (IS_ERR(root))
983 		deactivate_locked_super(s);
984 
985 	return root;
986 
987 error_close_devices:
988 	btrfs_close_devices(fs_devices);
989 error_fs_info:
990 	free_fs_info(fs_info);
991 	return ERR_PTR(error);
992 }
993 
994 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
995 {
996 	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
997 	struct btrfs_root *root = fs_info->tree_root;
998 	int ret;
999 
1000 	ret = btrfs_parse_options(root, data);
1001 	if (ret)
1002 		return -EINVAL;
1003 
1004 	if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1005 		return 0;
1006 
1007 	if (*flags & MS_RDONLY) {
1008 		sb->s_flags |= MS_RDONLY;
1009 
1010 		ret =  btrfs_commit_super(root);
1011 		WARN_ON(ret);
1012 	} else {
1013 		if (fs_info->fs_devices->rw_devices == 0)
1014 			return -EACCES;
1015 
1016 		if (btrfs_super_log_root(fs_info->super_copy) != 0)
1017 			return -EINVAL;
1018 
1019 		ret = btrfs_cleanup_fs_roots(fs_info);
1020 		WARN_ON(ret);
1021 
1022 		/* recover relocation */
1023 		ret = btrfs_recover_relocation(root);
1024 		WARN_ON(ret);
1025 
1026 		sb->s_flags &= ~MS_RDONLY;
1027 	}
1028 
1029 	return 0;
1030 }
1031 
1032 /* Used to sort the devices by max_avail(descending sort) */
1033 static int btrfs_cmp_device_free_bytes(const void *dev_info1,
1034 				       const void *dev_info2)
1035 {
1036 	if (((struct btrfs_device_info *)dev_info1)->max_avail >
1037 	    ((struct btrfs_device_info *)dev_info2)->max_avail)
1038 		return -1;
1039 	else if (((struct btrfs_device_info *)dev_info1)->max_avail <
1040 		 ((struct btrfs_device_info *)dev_info2)->max_avail)
1041 		return 1;
1042 	else
1043 	return 0;
1044 }
1045 
1046 /*
1047  * sort the devices by max_avail, in which max free extent size of each device
1048  * is stored.(Descending Sort)
1049  */
1050 static inline void btrfs_descending_sort_devices(
1051 					struct btrfs_device_info *devices,
1052 					size_t nr_devices)
1053 {
1054 	sort(devices, nr_devices, sizeof(struct btrfs_device_info),
1055 	     btrfs_cmp_device_free_bytes, NULL);
1056 }
1057 
1058 /*
1059  * The helper to calc the free space on the devices that can be used to store
1060  * file data.
1061  */
1062 static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes)
1063 {
1064 	struct btrfs_fs_info *fs_info = root->fs_info;
1065 	struct btrfs_device_info *devices_info;
1066 	struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
1067 	struct btrfs_device *device;
1068 	u64 skip_space;
1069 	u64 type;
1070 	u64 avail_space;
1071 	u64 used_space;
1072 	u64 min_stripe_size;
1073 	int min_stripes = 1, num_stripes = 1;
1074 	int i = 0, nr_devices;
1075 	int ret;
1076 
1077 	nr_devices = fs_info->fs_devices->open_devices;
1078 	BUG_ON(!nr_devices);
1079 
1080 	devices_info = kmalloc(sizeof(*devices_info) * nr_devices,
1081 			       GFP_NOFS);
1082 	if (!devices_info)
1083 		return -ENOMEM;
1084 
1085 	/* calc min stripe number for data space alloction */
1086 	type = btrfs_get_alloc_profile(root, 1);
1087 	if (type & BTRFS_BLOCK_GROUP_RAID0) {
1088 		min_stripes = 2;
1089 		num_stripes = nr_devices;
1090 	} else if (type & BTRFS_BLOCK_GROUP_RAID1) {
1091 		min_stripes = 2;
1092 		num_stripes = 2;
1093 	} else if (type & BTRFS_BLOCK_GROUP_RAID10) {
1094 		min_stripes = 4;
1095 		num_stripes = 4;
1096 	}
1097 
1098 	if (type & BTRFS_BLOCK_GROUP_DUP)
1099 		min_stripe_size = 2 * BTRFS_STRIPE_LEN;
1100 	else
1101 		min_stripe_size = BTRFS_STRIPE_LEN;
1102 
1103 	list_for_each_entry(device, &fs_devices->devices, dev_list) {
1104 		if (!device->in_fs_metadata || !device->bdev)
1105 			continue;
1106 
1107 		avail_space = device->total_bytes - device->bytes_used;
1108 
1109 		/* align with stripe_len */
1110 		do_div(avail_space, BTRFS_STRIPE_LEN);
1111 		avail_space *= BTRFS_STRIPE_LEN;
1112 
1113 		/*
1114 		 * In order to avoid overwritting the superblock on the drive,
1115 		 * btrfs starts at an offset of at least 1MB when doing chunk
1116 		 * allocation.
1117 		 */
1118 		skip_space = 1024 * 1024;
1119 
1120 		/* user can set the offset in fs_info->alloc_start. */
1121 		if (fs_info->alloc_start + BTRFS_STRIPE_LEN <=
1122 		    device->total_bytes)
1123 			skip_space = max(fs_info->alloc_start, skip_space);
1124 
1125 		/*
1126 		 * btrfs can not use the free space in [0, skip_space - 1],
1127 		 * we must subtract it from the total. In order to implement
1128 		 * it, we account the used space in this range first.
1129 		 */
1130 		ret = btrfs_account_dev_extents_size(device, 0, skip_space - 1,
1131 						     &used_space);
1132 		if (ret) {
1133 			kfree(devices_info);
1134 			return ret;
1135 		}
1136 
1137 		/* calc the free space in [0, skip_space - 1] */
1138 		skip_space -= used_space;
1139 
1140 		/*
1141 		 * we can use the free space in [0, skip_space - 1], subtract
1142 		 * it from the total.
1143 		 */
1144 		if (avail_space && avail_space >= skip_space)
1145 			avail_space -= skip_space;
1146 		else
1147 			avail_space = 0;
1148 
1149 		if (avail_space < min_stripe_size)
1150 			continue;
1151 
1152 		devices_info[i].dev = device;
1153 		devices_info[i].max_avail = avail_space;
1154 
1155 		i++;
1156 	}
1157 
1158 	nr_devices = i;
1159 
1160 	btrfs_descending_sort_devices(devices_info, nr_devices);
1161 
1162 	i = nr_devices - 1;
1163 	avail_space = 0;
1164 	while (nr_devices >= min_stripes) {
1165 		if (num_stripes > nr_devices)
1166 			num_stripes = nr_devices;
1167 
1168 		if (devices_info[i].max_avail >= min_stripe_size) {
1169 			int j;
1170 			u64 alloc_size;
1171 
1172 			avail_space += devices_info[i].max_avail * num_stripes;
1173 			alloc_size = devices_info[i].max_avail;
1174 			for (j = i + 1 - num_stripes; j <= i; j++)
1175 				devices_info[j].max_avail -= alloc_size;
1176 		}
1177 		i--;
1178 		nr_devices--;
1179 	}
1180 
1181 	kfree(devices_info);
1182 	*free_bytes = avail_space;
1183 	return 0;
1184 }
1185 
1186 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
1187 {
1188 	struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
1189 	struct btrfs_super_block *disk_super = fs_info->super_copy;
1190 	struct list_head *head = &fs_info->space_info;
1191 	struct btrfs_space_info *found;
1192 	u64 total_used = 0;
1193 	u64 total_free_data = 0;
1194 	int bits = dentry->d_sb->s_blocksize_bits;
1195 	__be32 *fsid = (__be32 *)fs_info->fsid;
1196 	int ret;
1197 
1198 	/* holding chunk_muext to avoid allocating new chunks */
1199 	mutex_lock(&fs_info->chunk_mutex);
1200 	rcu_read_lock();
1201 	list_for_each_entry_rcu(found, head, list) {
1202 		if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
1203 			total_free_data += found->disk_total - found->disk_used;
1204 			total_free_data -=
1205 				btrfs_account_ro_block_groups_free_space(found);
1206 		}
1207 
1208 		total_used += found->disk_used;
1209 	}
1210 	rcu_read_unlock();
1211 
1212 	buf->f_namelen = BTRFS_NAME_LEN;
1213 	buf->f_blocks = btrfs_super_total_bytes(disk_super) >> bits;
1214 	buf->f_bfree = buf->f_blocks - (total_used >> bits);
1215 	buf->f_bsize = dentry->d_sb->s_blocksize;
1216 	buf->f_type = BTRFS_SUPER_MAGIC;
1217 	buf->f_bavail = total_free_data;
1218 	ret = btrfs_calc_avail_data_space(fs_info->tree_root, &total_free_data);
1219 	if (ret) {
1220 		mutex_unlock(&fs_info->chunk_mutex);
1221 		return ret;
1222 	}
1223 	buf->f_bavail += total_free_data;
1224 	buf->f_bavail = buf->f_bavail >> bits;
1225 	mutex_unlock(&fs_info->chunk_mutex);
1226 
1227 	/* We treat it as constant endianness (it doesn't matter _which_)
1228 	   because we want the fsid to come out the same whether mounted
1229 	   on a big-endian or little-endian host */
1230 	buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
1231 	buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
1232 	/* Mask in the root object ID too, to disambiguate subvols */
1233 	buf->f_fsid.val[0] ^= BTRFS_I(dentry->d_inode)->root->objectid >> 32;
1234 	buf->f_fsid.val[1] ^= BTRFS_I(dentry->d_inode)->root->objectid;
1235 
1236 	return 0;
1237 }
1238 
1239 static void btrfs_kill_super(struct super_block *sb)
1240 {
1241 	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1242 	kill_anon_super(sb);
1243 	free_fs_info(fs_info);
1244 }
1245 
1246 static struct file_system_type btrfs_fs_type = {
1247 	.owner		= THIS_MODULE,
1248 	.name		= "btrfs",
1249 	.mount		= btrfs_mount,
1250 	.kill_sb	= btrfs_kill_super,
1251 	.fs_flags	= FS_REQUIRES_DEV,
1252 };
1253 
1254 /*
1255  * used by btrfsctl to scan devices when no FS is mounted
1256  */
1257 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
1258 				unsigned long arg)
1259 {
1260 	struct btrfs_ioctl_vol_args *vol;
1261 	struct btrfs_fs_devices *fs_devices;
1262 	int ret = -ENOTTY;
1263 
1264 	if (!capable(CAP_SYS_ADMIN))
1265 		return -EPERM;
1266 
1267 	vol = memdup_user((void __user *)arg, sizeof(*vol));
1268 	if (IS_ERR(vol))
1269 		return PTR_ERR(vol);
1270 
1271 	switch (cmd) {
1272 	case BTRFS_IOC_SCAN_DEV:
1273 		ret = btrfs_scan_one_device(vol->name, FMODE_READ,
1274 					    &btrfs_fs_type, &fs_devices);
1275 		break;
1276 	}
1277 
1278 	kfree(vol);
1279 	return ret;
1280 }
1281 
1282 static int btrfs_freeze(struct super_block *sb)
1283 {
1284 	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1285 	mutex_lock(&fs_info->transaction_kthread_mutex);
1286 	mutex_lock(&fs_info->cleaner_mutex);
1287 	return 0;
1288 }
1289 
1290 static int btrfs_unfreeze(struct super_block *sb)
1291 {
1292 	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1293 	mutex_unlock(&fs_info->cleaner_mutex);
1294 	mutex_unlock(&fs_info->transaction_kthread_mutex);
1295 	return 0;
1296 }
1297 
1298 static void btrfs_fs_dirty_inode(struct inode *inode, int flags)
1299 {
1300 	int ret;
1301 
1302 	ret = btrfs_dirty_inode(inode);
1303 	if (ret)
1304 		printk_ratelimited(KERN_ERR "btrfs: fail to dirty inode %Lu "
1305 				   "error %d\n", btrfs_ino(inode), ret);
1306 }
1307 
1308 static const struct super_operations btrfs_super_ops = {
1309 	.drop_inode	= btrfs_drop_inode,
1310 	.evict_inode	= btrfs_evict_inode,
1311 	.put_super	= btrfs_put_super,
1312 	.sync_fs	= btrfs_sync_fs,
1313 	.show_options	= btrfs_show_options,
1314 	.write_inode	= btrfs_write_inode,
1315 	.dirty_inode	= btrfs_fs_dirty_inode,
1316 	.alloc_inode	= btrfs_alloc_inode,
1317 	.destroy_inode	= btrfs_destroy_inode,
1318 	.statfs		= btrfs_statfs,
1319 	.remount_fs	= btrfs_remount,
1320 	.freeze_fs	= btrfs_freeze,
1321 	.unfreeze_fs	= btrfs_unfreeze,
1322 };
1323 
1324 static const struct file_operations btrfs_ctl_fops = {
1325 	.unlocked_ioctl	 = btrfs_control_ioctl,
1326 	.compat_ioctl = btrfs_control_ioctl,
1327 	.owner	 = THIS_MODULE,
1328 	.llseek = noop_llseek,
1329 };
1330 
1331 static struct miscdevice btrfs_misc = {
1332 	.minor		= BTRFS_MINOR,
1333 	.name		= "btrfs-control",
1334 	.fops		= &btrfs_ctl_fops
1335 };
1336 
1337 MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
1338 MODULE_ALIAS("devname:btrfs-control");
1339 
1340 static int btrfs_interface_init(void)
1341 {
1342 	return misc_register(&btrfs_misc);
1343 }
1344 
1345 static void btrfs_interface_exit(void)
1346 {
1347 	if (misc_deregister(&btrfs_misc) < 0)
1348 		printk(KERN_INFO "misc_deregister failed for control device");
1349 }
1350 
1351 static int __init init_btrfs_fs(void)
1352 {
1353 	int err;
1354 
1355 	err = btrfs_init_sysfs();
1356 	if (err)
1357 		return err;
1358 
1359 	err = btrfs_init_compress();
1360 	if (err)
1361 		goto free_sysfs;
1362 
1363 	err = btrfs_init_cachep();
1364 	if (err)
1365 		goto free_compress;
1366 
1367 	err = extent_io_init();
1368 	if (err)
1369 		goto free_cachep;
1370 
1371 	err = extent_map_init();
1372 	if (err)
1373 		goto free_extent_io;
1374 
1375 	err = btrfs_delayed_inode_init();
1376 	if (err)
1377 		goto free_extent_map;
1378 
1379 	err = btrfs_interface_init();
1380 	if (err)
1381 		goto free_delayed_inode;
1382 
1383 	err = register_filesystem(&btrfs_fs_type);
1384 	if (err)
1385 		goto unregister_ioctl;
1386 
1387 	printk(KERN_INFO "%s loaded\n", BTRFS_BUILD_VERSION);
1388 	return 0;
1389 
1390 unregister_ioctl:
1391 	btrfs_interface_exit();
1392 free_delayed_inode:
1393 	btrfs_delayed_inode_exit();
1394 free_extent_map:
1395 	extent_map_exit();
1396 free_extent_io:
1397 	extent_io_exit();
1398 free_cachep:
1399 	btrfs_destroy_cachep();
1400 free_compress:
1401 	btrfs_exit_compress();
1402 free_sysfs:
1403 	btrfs_exit_sysfs();
1404 	return err;
1405 }
1406 
1407 static void __exit exit_btrfs_fs(void)
1408 {
1409 	btrfs_destroy_cachep();
1410 	btrfs_delayed_inode_exit();
1411 	extent_map_exit();
1412 	extent_io_exit();
1413 	btrfs_interface_exit();
1414 	unregister_filesystem(&btrfs_fs_type);
1415 	btrfs_exit_sysfs();
1416 	btrfs_cleanup_fs_uuids();
1417 	btrfs_exit_compress();
1418 }
1419 
1420 module_init(init_btrfs_fs)
1421 module_exit(exit_btrfs_fs)
1422 
1423 MODULE_LICENSE("GPL");
1424