FRV: Use generic show_interrupts()
[cris-mirror.git] / fs / btrfs / super.c
blobd39a9895d93288a6315e838cfe05dc1e1a65e7f4
1 /*
2 * Copyright (C) 2007 Oracle. All rights reserved.
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.
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.
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.
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 "compat.h"
43 #include "ctree.h"
44 #include "disk-io.h"
45 #include "transaction.h"
46 #include "btrfs_inode.h"
47 #include "ioctl.h"
48 #include "print-tree.h"
49 #include "xattr.h"
50 #include "volumes.h"
51 #include "version.h"
52 #include "export.h"
53 #include "compression.h"
55 static const struct super_operations btrfs_super_ops;
57 static const char *btrfs_decode_error(struct btrfs_fs_info *fs_info, int errno,
58 char nbuf[16])
60 char *errstr = NULL;
62 switch (errno) {
63 case -EIO:
64 errstr = "IO failure";
65 break;
66 case -ENOMEM:
67 errstr = "Out of memory";
68 break;
69 case -EROFS:
70 errstr = "Readonly filesystem";
71 break;
72 default:
73 if (nbuf) {
74 if (snprintf(nbuf, 16, "error %d", -errno) >= 0)
75 errstr = nbuf;
77 break;
80 return errstr;
83 static void __save_error_info(struct btrfs_fs_info *fs_info)
86 * today we only save the error info into ram. Long term we'll
87 * also send it down to the disk
89 fs_info->fs_state = BTRFS_SUPER_FLAG_ERROR;
92 /* NOTE:
93 * We move write_super stuff at umount in order to avoid deadlock
94 * for umount hold all lock.
96 static void save_error_info(struct btrfs_fs_info *fs_info)
98 __save_error_info(fs_info);
101 /* btrfs handle error by forcing the filesystem readonly */
102 static void btrfs_handle_error(struct btrfs_fs_info *fs_info)
104 struct super_block *sb = fs_info->sb;
106 if (sb->s_flags & MS_RDONLY)
107 return;
109 if (fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
110 sb->s_flags |= MS_RDONLY;
111 printk(KERN_INFO "btrfs is forced readonly\n");
116 * __btrfs_std_error decodes expected errors from the caller and
117 * invokes the approciate error response.
119 void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function,
120 unsigned int line, int errno)
122 struct super_block *sb = fs_info->sb;
123 char nbuf[16];
124 const char *errstr;
127 * Special case: if the error is EROFS, and we're already
128 * under MS_RDONLY, then it is safe here.
130 if (errno == -EROFS && (sb->s_flags & MS_RDONLY))
131 return;
133 errstr = btrfs_decode_error(fs_info, errno, nbuf);
134 printk(KERN_CRIT "BTRFS error (device %s) in %s:%d: %s\n",
135 sb->s_id, function, line, errstr);
136 save_error_info(fs_info);
138 btrfs_handle_error(fs_info);
141 static void btrfs_put_super(struct super_block *sb)
143 struct btrfs_root *root = btrfs_sb(sb);
144 int ret;
146 ret = close_ctree(root);
147 sb->s_fs_info = NULL;
149 (void)ret; /* FIXME: need to fix VFS to return error? */
152 enum {
153 Opt_degraded, Opt_subvol, Opt_subvolid, Opt_device, Opt_nodatasum,
154 Opt_nodatacow, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd,
155 Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl, Opt_compress,
156 Opt_compress_type, Opt_compress_force, Opt_compress_force_type,
157 Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard,
158 Opt_space_cache, Opt_clear_cache, Opt_user_subvol_rm_allowed,
159 Opt_enospc_debug, Opt_err,
162 static match_table_t tokens = {
163 {Opt_degraded, "degraded"},
164 {Opt_subvol, "subvol=%s"},
165 {Opt_subvolid, "subvolid=%d"},
166 {Opt_device, "device=%s"},
167 {Opt_nodatasum, "nodatasum"},
168 {Opt_nodatacow, "nodatacow"},
169 {Opt_nobarrier, "nobarrier"},
170 {Opt_max_inline, "max_inline=%s"},
171 {Opt_alloc_start, "alloc_start=%s"},
172 {Opt_thread_pool, "thread_pool=%d"},
173 {Opt_compress, "compress"},
174 {Opt_compress_type, "compress=%s"},
175 {Opt_compress_force, "compress-force"},
176 {Opt_compress_force_type, "compress-force=%s"},
177 {Opt_ssd, "ssd"},
178 {Opt_ssd_spread, "ssd_spread"},
179 {Opt_nossd, "nossd"},
180 {Opt_noacl, "noacl"},
181 {Opt_notreelog, "notreelog"},
182 {Opt_flushoncommit, "flushoncommit"},
183 {Opt_ratio, "metadata_ratio=%d"},
184 {Opt_discard, "discard"},
185 {Opt_space_cache, "space_cache"},
186 {Opt_clear_cache, "clear_cache"},
187 {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
188 {Opt_enospc_debug, "enospc_debug"},
189 {Opt_err, NULL},
193 * Regular mount options parser. Everything that is needed only when
194 * reading in a new superblock is parsed here.
196 int btrfs_parse_options(struct btrfs_root *root, char *options)
198 struct btrfs_fs_info *info = root->fs_info;
199 substring_t args[MAX_OPT_ARGS];
200 char *p, *num, *orig;
201 int intarg;
202 int ret = 0;
203 char *compress_type;
204 bool compress_force = false;
206 if (!options)
207 return 0;
210 * strsep changes the string, duplicate it because parse_options
211 * gets called twice
213 options = kstrdup(options, GFP_NOFS);
214 if (!options)
215 return -ENOMEM;
217 orig = options;
219 while ((p = strsep(&options, ",")) != NULL) {
220 int token;
221 if (!*p)
222 continue;
224 token = match_token(p, tokens, args);
225 switch (token) {
226 case Opt_degraded:
227 printk(KERN_INFO "btrfs: allowing degraded mounts\n");
228 btrfs_set_opt(info->mount_opt, DEGRADED);
229 break;
230 case Opt_subvol:
231 case Opt_subvolid:
232 case Opt_device:
234 * These are parsed by btrfs_parse_early_options
235 * and can be happily ignored here.
237 break;
238 case Opt_nodatasum:
239 printk(KERN_INFO "btrfs: setting nodatasum\n");
240 btrfs_set_opt(info->mount_opt, NODATASUM);
241 break;
242 case Opt_nodatacow:
243 printk(KERN_INFO "btrfs: setting nodatacow\n");
244 btrfs_set_opt(info->mount_opt, NODATACOW);
245 btrfs_set_opt(info->mount_opt, NODATASUM);
246 break;
247 case Opt_compress_force:
248 case Opt_compress_force_type:
249 compress_force = true;
250 case Opt_compress:
251 case Opt_compress_type:
252 if (token == Opt_compress ||
253 token == Opt_compress_force ||
254 strcmp(args[0].from, "zlib") == 0) {
255 compress_type = "zlib";
256 info->compress_type = BTRFS_COMPRESS_ZLIB;
257 } else if (strcmp(args[0].from, "lzo") == 0) {
258 compress_type = "lzo";
259 info->compress_type = BTRFS_COMPRESS_LZO;
260 } else {
261 ret = -EINVAL;
262 goto out;
265 btrfs_set_opt(info->mount_opt, COMPRESS);
266 if (compress_force) {
267 btrfs_set_opt(info->mount_opt, FORCE_COMPRESS);
268 pr_info("btrfs: force %s compression\n",
269 compress_type);
270 } else
271 pr_info("btrfs: use %s compression\n",
272 compress_type);
273 break;
274 case Opt_ssd:
275 printk(KERN_INFO "btrfs: use ssd allocation scheme\n");
276 btrfs_set_opt(info->mount_opt, SSD);
277 break;
278 case Opt_ssd_spread:
279 printk(KERN_INFO "btrfs: use spread ssd "
280 "allocation scheme\n");
281 btrfs_set_opt(info->mount_opt, SSD);
282 btrfs_set_opt(info->mount_opt, SSD_SPREAD);
283 break;
284 case Opt_nossd:
285 printk(KERN_INFO "btrfs: not using ssd allocation "
286 "scheme\n");
287 btrfs_set_opt(info->mount_opt, NOSSD);
288 btrfs_clear_opt(info->mount_opt, SSD);
289 btrfs_clear_opt(info->mount_opt, SSD_SPREAD);
290 break;
291 case Opt_nobarrier:
292 printk(KERN_INFO "btrfs: turning off barriers\n");
293 btrfs_set_opt(info->mount_opt, NOBARRIER);
294 break;
295 case Opt_thread_pool:
296 intarg = 0;
297 match_int(&args[0], &intarg);
298 if (intarg) {
299 info->thread_pool_size = intarg;
300 printk(KERN_INFO "btrfs: thread pool %d\n",
301 info->thread_pool_size);
303 break;
304 case Opt_max_inline:
305 num = match_strdup(&args[0]);
306 if (num) {
307 info->max_inline = memparse(num, NULL);
308 kfree(num);
310 if (info->max_inline) {
311 info->max_inline = max_t(u64,
312 info->max_inline,
313 root->sectorsize);
315 printk(KERN_INFO "btrfs: max_inline at %llu\n",
316 (unsigned long long)info->max_inline);
318 break;
319 case Opt_alloc_start:
320 num = match_strdup(&args[0]);
321 if (num) {
322 info->alloc_start = memparse(num, NULL);
323 kfree(num);
324 printk(KERN_INFO
325 "btrfs: allocations start at %llu\n",
326 (unsigned long long)info->alloc_start);
328 break;
329 case Opt_noacl:
330 root->fs_info->sb->s_flags &= ~MS_POSIXACL;
331 break;
332 case Opt_notreelog:
333 printk(KERN_INFO "btrfs: disabling tree log\n");
334 btrfs_set_opt(info->mount_opt, NOTREELOG);
335 break;
336 case Opt_flushoncommit:
337 printk(KERN_INFO "btrfs: turning on flush-on-commit\n");
338 btrfs_set_opt(info->mount_opt, FLUSHONCOMMIT);
339 break;
340 case Opt_ratio:
341 intarg = 0;
342 match_int(&args[0], &intarg);
343 if (intarg) {
344 info->metadata_ratio = intarg;
345 printk(KERN_INFO "btrfs: metadata ratio %d\n",
346 info->metadata_ratio);
348 break;
349 case Opt_discard:
350 btrfs_set_opt(info->mount_opt, DISCARD);
351 break;
352 case Opt_space_cache:
353 printk(KERN_INFO "btrfs: enabling disk space caching\n");
354 btrfs_set_opt(info->mount_opt, SPACE_CACHE);
355 break;
356 case Opt_clear_cache:
357 printk(KERN_INFO "btrfs: force clearing of disk cache\n");
358 btrfs_set_opt(info->mount_opt, CLEAR_CACHE);
359 break;
360 case Opt_user_subvol_rm_allowed:
361 btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
362 break;
363 case Opt_enospc_debug:
364 btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
365 break;
366 case Opt_err:
367 printk(KERN_INFO "btrfs: unrecognized mount option "
368 "'%s'\n", p);
369 ret = -EINVAL;
370 goto out;
371 default:
372 break;
375 out:
376 kfree(orig);
377 return ret;
381 * Parse mount options that are required early in the mount process.
383 * All other options will be parsed on much later in the mount process and
384 * only when we need to allocate a new super block.
386 static int btrfs_parse_early_options(const char *options, fmode_t flags,
387 void *holder, char **subvol_name, u64 *subvol_objectid,
388 struct btrfs_fs_devices **fs_devices)
390 substring_t args[MAX_OPT_ARGS];
391 char *opts, *orig, *p;
392 int error = 0;
393 int intarg;
395 if (!options)
396 goto out;
399 * strsep changes the string, duplicate it because parse_options
400 * gets called twice
402 opts = kstrdup(options, GFP_KERNEL);
403 if (!opts)
404 return -ENOMEM;
405 orig = opts;
407 while ((p = strsep(&opts, ",")) != NULL) {
408 int token;
409 if (!*p)
410 continue;
412 token = match_token(p, tokens, args);
413 switch (token) {
414 case Opt_subvol:
415 *subvol_name = match_strdup(&args[0]);
416 break;
417 case Opt_subvolid:
418 intarg = 0;
419 error = match_int(&args[0], &intarg);
420 if (!error) {
421 /* we want the original fs_tree */
422 if (!intarg)
423 *subvol_objectid =
424 BTRFS_FS_TREE_OBJECTID;
425 else
426 *subvol_objectid = intarg;
428 break;
429 case Opt_device:
430 error = btrfs_scan_one_device(match_strdup(&args[0]),
431 flags, holder, fs_devices);
432 if (error)
433 goto out_free_opts;
434 break;
435 default:
436 break;
440 out_free_opts:
441 kfree(orig);
442 out:
444 * If no subvolume name is specified we use the default one. Allocate
445 * a copy of the string "." here so that code later in the
446 * mount path doesn't care if it's the default volume or another one.
448 if (!*subvol_name) {
449 *subvol_name = kstrdup(".", GFP_KERNEL);
450 if (!*subvol_name)
451 return -ENOMEM;
453 return error;
456 static struct dentry *get_default_root(struct super_block *sb,
457 u64 subvol_objectid)
459 struct btrfs_root *root = sb->s_fs_info;
460 struct btrfs_root *new_root;
461 struct btrfs_dir_item *di;
462 struct btrfs_path *path;
463 struct btrfs_key location;
464 struct inode *inode;
465 struct dentry *dentry;
466 u64 dir_id;
467 int new = 0;
470 * We have a specific subvol we want to mount, just setup location and
471 * go look up the root.
473 if (subvol_objectid) {
474 location.objectid = subvol_objectid;
475 location.type = BTRFS_ROOT_ITEM_KEY;
476 location.offset = (u64)-1;
477 goto find_root;
480 path = btrfs_alloc_path();
481 if (!path)
482 return ERR_PTR(-ENOMEM);
483 path->leave_spinning = 1;
486 * Find the "default" dir item which points to the root item that we
487 * will mount by default if we haven't been given a specific subvolume
488 * to mount.
490 dir_id = btrfs_super_root_dir(&root->fs_info->super_copy);
491 di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
492 if (IS_ERR(di))
493 return ERR_CAST(di);
494 if (!di) {
496 * Ok the default dir item isn't there. This is weird since
497 * it's always been there, but don't freak out, just try and
498 * mount to root most subvolume.
500 btrfs_free_path(path);
501 dir_id = BTRFS_FIRST_FREE_OBJECTID;
502 new_root = root->fs_info->fs_root;
503 goto setup_root;
506 btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
507 btrfs_free_path(path);
509 find_root:
510 new_root = btrfs_read_fs_root_no_name(root->fs_info, &location);
511 if (IS_ERR(new_root))
512 return ERR_CAST(new_root);
514 if (btrfs_root_refs(&new_root->root_item) == 0)
515 return ERR_PTR(-ENOENT);
517 dir_id = btrfs_root_dirid(&new_root->root_item);
518 setup_root:
519 location.objectid = dir_id;
520 location.type = BTRFS_INODE_ITEM_KEY;
521 location.offset = 0;
523 inode = btrfs_iget(sb, &location, new_root, &new);
524 if (IS_ERR(inode))
525 return ERR_CAST(inode);
528 * If we're just mounting the root most subvol put the inode and return
529 * a reference to the dentry. We will have already gotten a reference
530 * to the inode in btrfs_fill_super so we're good to go.
532 if (!new && sb->s_root->d_inode == inode) {
533 iput(inode);
534 return dget(sb->s_root);
537 if (new) {
538 const struct qstr name = { .name = "/", .len = 1 };
541 * New inode, we need to make the dentry a sibling of s_root so
542 * everything gets cleaned up properly on unmount.
544 dentry = d_alloc(sb->s_root, &name);
545 if (!dentry) {
546 iput(inode);
547 return ERR_PTR(-ENOMEM);
549 d_splice_alias(inode, dentry);
550 } else {
552 * We found the inode in cache, just find a dentry for it and
553 * put the reference to the inode we just got.
555 dentry = d_find_alias(inode);
556 iput(inode);
559 return dentry;
562 static int btrfs_fill_super(struct super_block *sb,
563 struct btrfs_fs_devices *fs_devices,
564 void *data, int silent)
566 struct inode *inode;
567 struct dentry *root_dentry;
568 struct btrfs_root *tree_root;
569 struct btrfs_key key;
570 int err;
572 sb->s_maxbytes = MAX_LFS_FILESIZE;
573 sb->s_magic = BTRFS_SUPER_MAGIC;
574 sb->s_op = &btrfs_super_ops;
575 sb->s_d_op = &btrfs_dentry_operations;
576 sb->s_export_op = &btrfs_export_ops;
577 sb->s_xattr = btrfs_xattr_handlers;
578 sb->s_time_gran = 1;
579 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
580 sb->s_flags |= MS_POSIXACL;
581 #endif
583 tree_root = open_ctree(sb, fs_devices, (char *)data);
585 if (IS_ERR(tree_root)) {
586 printk("btrfs: open_ctree failed\n");
587 return PTR_ERR(tree_root);
589 sb->s_fs_info = tree_root;
591 key.objectid = BTRFS_FIRST_FREE_OBJECTID;
592 key.type = BTRFS_INODE_ITEM_KEY;
593 key.offset = 0;
594 inode = btrfs_iget(sb, &key, tree_root->fs_info->fs_root, NULL);
595 if (IS_ERR(inode)) {
596 err = PTR_ERR(inode);
597 goto fail_close;
600 root_dentry = d_alloc_root(inode);
601 if (!root_dentry) {
602 iput(inode);
603 err = -ENOMEM;
604 goto fail_close;
607 sb->s_root = root_dentry;
609 save_mount_options(sb, data);
610 return 0;
612 fail_close:
613 close_ctree(tree_root);
614 return err;
617 int btrfs_sync_fs(struct super_block *sb, int wait)
619 struct btrfs_trans_handle *trans;
620 struct btrfs_root *root = btrfs_sb(sb);
621 int ret;
623 if (!wait) {
624 filemap_flush(root->fs_info->btree_inode->i_mapping);
625 return 0;
628 btrfs_start_delalloc_inodes(root, 0);
629 btrfs_wait_ordered_extents(root, 0, 0);
631 trans = btrfs_start_transaction(root, 0);
632 if (IS_ERR(trans))
633 return PTR_ERR(trans);
634 ret = btrfs_commit_transaction(trans, root);
635 return ret;
638 static int btrfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
640 struct btrfs_root *root = btrfs_sb(vfs->mnt_sb);
641 struct btrfs_fs_info *info = root->fs_info;
643 if (btrfs_test_opt(root, DEGRADED))
644 seq_puts(seq, ",degraded");
645 if (btrfs_test_opt(root, NODATASUM))
646 seq_puts(seq, ",nodatasum");
647 if (btrfs_test_opt(root, NODATACOW))
648 seq_puts(seq, ",nodatacow");
649 if (btrfs_test_opt(root, NOBARRIER))
650 seq_puts(seq, ",nobarrier");
651 if (info->max_inline != 8192 * 1024)
652 seq_printf(seq, ",max_inline=%llu",
653 (unsigned long long)info->max_inline);
654 if (info->alloc_start != 0)
655 seq_printf(seq, ",alloc_start=%llu",
656 (unsigned long long)info->alloc_start);
657 if (info->thread_pool_size != min_t(unsigned long,
658 num_online_cpus() + 2, 8))
659 seq_printf(seq, ",thread_pool=%d", info->thread_pool_size);
660 if (btrfs_test_opt(root, COMPRESS))
661 seq_puts(seq, ",compress");
662 if (btrfs_test_opt(root, NOSSD))
663 seq_puts(seq, ",nossd");
664 if (btrfs_test_opt(root, SSD_SPREAD))
665 seq_puts(seq, ",ssd_spread");
666 else if (btrfs_test_opt(root, SSD))
667 seq_puts(seq, ",ssd");
668 if (btrfs_test_opt(root, NOTREELOG))
669 seq_puts(seq, ",notreelog");
670 if (btrfs_test_opt(root, FLUSHONCOMMIT))
671 seq_puts(seq, ",flushoncommit");
672 if (btrfs_test_opt(root, DISCARD))
673 seq_puts(seq, ",discard");
674 if (!(root->fs_info->sb->s_flags & MS_POSIXACL))
675 seq_puts(seq, ",noacl");
676 return 0;
679 static int btrfs_test_super(struct super_block *s, void *data)
681 struct btrfs_root *test_root = data;
682 struct btrfs_root *root = btrfs_sb(s);
685 * If this super block is going away, return false as it
686 * can't match as an existing super block.
688 if (!atomic_read(&s->s_active))
689 return 0;
690 return root->fs_info->fs_devices == test_root->fs_info->fs_devices;
693 static int btrfs_set_super(struct super_block *s, void *data)
695 s->s_fs_info = data;
697 return set_anon_super(s, data);
702 * Find a superblock for the given device / mount point.
704 * Note: This is based on get_sb_bdev from fs/super.c with a few additions
705 * for multiple device setup. Make sure to keep it in sync.
707 static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
708 const char *dev_name, void *data)
710 struct block_device *bdev = NULL;
711 struct super_block *s;
712 struct dentry *root;
713 struct btrfs_fs_devices *fs_devices = NULL;
714 struct btrfs_root *tree_root = NULL;
715 struct btrfs_fs_info *fs_info = NULL;
716 fmode_t mode = FMODE_READ;
717 char *subvol_name = NULL;
718 u64 subvol_objectid = 0;
719 int error = 0;
721 if (!(flags & MS_RDONLY))
722 mode |= FMODE_WRITE;
724 error = btrfs_parse_early_options(data, mode, fs_type,
725 &subvol_name, &subvol_objectid,
726 &fs_devices);
727 if (error)
728 return ERR_PTR(error);
730 error = btrfs_scan_one_device(dev_name, mode, fs_type, &fs_devices);
731 if (error)
732 goto error_free_subvol_name;
734 error = btrfs_open_devices(fs_devices, mode, fs_type);
735 if (error)
736 goto error_free_subvol_name;
738 if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
739 error = -EACCES;
740 goto error_close_devices;
744 * Setup a dummy root and fs_info for test/set super. This is because
745 * we don't actually fill this stuff out until open_ctree, but we need
746 * it for searching for existing supers, so this lets us do that and
747 * then open_ctree will properly initialize everything later.
749 fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_NOFS);
750 tree_root = kzalloc(sizeof(struct btrfs_root), GFP_NOFS);
751 if (!fs_info || !tree_root) {
752 error = -ENOMEM;
753 goto error_close_devices;
755 fs_info->tree_root = tree_root;
756 fs_info->fs_devices = fs_devices;
757 tree_root->fs_info = fs_info;
759 bdev = fs_devices->latest_bdev;
760 s = sget(fs_type, btrfs_test_super, btrfs_set_super, tree_root);
761 if (IS_ERR(s))
762 goto error_s;
764 if (s->s_root) {
765 if ((flags ^ s->s_flags) & MS_RDONLY) {
766 deactivate_locked_super(s);
767 error = -EBUSY;
768 goto error_close_devices;
771 btrfs_close_devices(fs_devices);
772 kfree(fs_info);
773 kfree(tree_root);
774 } else {
775 char b[BDEVNAME_SIZE];
777 s->s_flags = flags;
778 strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
779 error = btrfs_fill_super(s, fs_devices, data,
780 flags & MS_SILENT ? 1 : 0);
781 if (error) {
782 deactivate_locked_super(s);
783 goto error_free_subvol_name;
786 btrfs_sb(s)->fs_info->bdev_holder = fs_type;
787 s->s_flags |= MS_ACTIVE;
790 root = get_default_root(s, subvol_objectid);
791 if (IS_ERR(root)) {
792 error = PTR_ERR(root);
793 deactivate_locked_super(s);
794 goto error_free_subvol_name;
796 /* if they gave us a subvolume name bind mount into that */
797 if (strcmp(subvol_name, ".")) {
798 struct dentry *new_root;
799 mutex_lock(&root->d_inode->i_mutex);
800 new_root = lookup_one_len(subvol_name, root,
801 strlen(subvol_name));
802 mutex_unlock(&root->d_inode->i_mutex);
804 if (IS_ERR(new_root)) {
805 dput(root);
806 deactivate_locked_super(s);
807 error = PTR_ERR(new_root);
808 goto error_free_subvol_name;
810 if (!new_root->d_inode) {
811 dput(root);
812 dput(new_root);
813 deactivate_locked_super(s);
814 error = -ENXIO;
815 goto error_free_subvol_name;
817 dput(root);
818 root = new_root;
821 kfree(subvol_name);
822 return root;
824 error_s:
825 error = PTR_ERR(s);
826 error_close_devices:
827 btrfs_close_devices(fs_devices);
828 kfree(fs_info);
829 kfree(tree_root);
830 error_free_subvol_name:
831 kfree(subvol_name);
832 return ERR_PTR(error);
835 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
837 struct btrfs_root *root = btrfs_sb(sb);
838 int ret;
840 ret = btrfs_parse_options(root, data);
841 if (ret)
842 return -EINVAL;
844 if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
845 return 0;
847 if (*flags & MS_RDONLY) {
848 sb->s_flags |= MS_RDONLY;
850 ret = btrfs_commit_super(root);
851 WARN_ON(ret);
852 } else {
853 if (root->fs_info->fs_devices->rw_devices == 0)
854 return -EACCES;
856 if (btrfs_super_log_root(&root->fs_info->super_copy) != 0)
857 return -EINVAL;
859 ret = btrfs_cleanup_fs_roots(root->fs_info);
860 WARN_ON(ret);
862 /* recover relocation */
863 ret = btrfs_recover_relocation(root);
864 WARN_ON(ret);
866 sb->s_flags &= ~MS_RDONLY;
869 return 0;
873 * The helper to calc the free space on the devices that can be used to store
874 * file data.
876 static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes)
878 struct btrfs_fs_info *fs_info = root->fs_info;
879 struct btrfs_device_info *devices_info;
880 struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
881 struct btrfs_device *device;
882 u64 skip_space;
883 u64 type;
884 u64 avail_space;
885 u64 used_space;
886 u64 min_stripe_size;
887 int min_stripes = 1;
888 int i = 0, nr_devices;
889 int ret;
891 nr_devices = fs_info->fs_devices->rw_devices;
892 BUG_ON(!nr_devices);
894 devices_info = kmalloc(sizeof(*devices_info) * nr_devices,
895 GFP_NOFS);
896 if (!devices_info)
897 return -ENOMEM;
899 /* calc min stripe number for data space alloction */
900 type = btrfs_get_alloc_profile(root, 1);
901 if (type & BTRFS_BLOCK_GROUP_RAID0)
902 min_stripes = 2;
903 else if (type & BTRFS_BLOCK_GROUP_RAID1)
904 min_stripes = 2;
905 else if (type & BTRFS_BLOCK_GROUP_RAID10)
906 min_stripes = 4;
908 if (type & BTRFS_BLOCK_GROUP_DUP)
909 min_stripe_size = 2 * BTRFS_STRIPE_LEN;
910 else
911 min_stripe_size = BTRFS_STRIPE_LEN;
913 list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
914 if (!device->in_fs_metadata)
915 continue;
917 avail_space = device->total_bytes - device->bytes_used;
919 /* align with stripe_len */
920 do_div(avail_space, BTRFS_STRIPE_LEN);
921 avail_space *= BTRFS_STRIPE_LEN;
924 * In order to avoid overwritting the superblock on the drive,
925 * btrfs starts at an offset of at least 1MB when doing chunk
926 * allocation.
928 skip_space = 1024 * 1024;
930 /* user can set the offset in fs_info->alloc_start. */
931 if (fs_info->alloc_start + BTRFS_STRIPE_LEN <=
932 device->total_bytes)
933 skip_space = max(fs_info->alloc_start, skip_space);
936 * btrfs can not use the free space in [0, skip_space - 1],
937 * we must subtract it from the total. In order to implement
938 * it, we account the used space in this range first.
940 ret = btrfs_account_dev_extents_size(device, 0, skip_space - 1,
941 &used_space);
942 if (ret) {
943 kfree(devices_info);
944 return ret;
947 /* calc the free space in [0, skip_space - 1] */
948 skip_space -= used_space;
951 * we can use the free space in [0, skip_space - 1], subtract
952 * it from the total.
954 if (avail_space && avail_space >= skip_space)
955 avail_space -= skip_space;
956 else
957 avail_space = 0;
959 if (avail_space < min_stripe_size)
960 continue;
962 devices_info[i].dev = device;
963 devices_info[i].max_avail = avail_space;
965 i++;
968 nr_devices = i;
970 btrfs_descending_sort_devices(devices_info, nr_devices);
972 i = nr_devices - 1;
973 avail_space = 0;
974 while (nr_devices >= min_stripes) {
975 if (devices_info[i].max_avail >= min_stripe_size) {
976 int j;
977 u64 alloc_size;
979 avail_space += devices_info[i].max_avail * min_stripes;
980 alloc_size = devices_info[i].max_avail;
981 for (j = i + 1 - min_stripes; j <= i; j++)
982 devices_info[j].max_avail -= alloc_size;
984 i--;
985 nr_devices--;
988 kfree(devices_info);
989 *free_bytes = avail_space;
990 return 0;
993 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
995 struct btrfs_root *root = btrfs_sb(dentry->d_sb);
996 struct btrfs_super_block *disk_super = &root->fs_info->super_copy;
997 struct list_head *head = &root->fs_info->space_info;
998 struct btrfs_space_info *found;
999 u64 total_used = 0;
1000 u64 total_free_data = 0;
1001 int bits = dentry->d_sb->s_blocksize_bits;
1002 __be32 *fsid = (__be32 *)root->fs_info->fsid;
1003 int ret;
1005 /* holding chunk_muext to avoid allocating new chunks */
1006 mutex_lock(&root->fs_info->chunk_mutex);
1007 rcu_read_lock();
1008 list_for_each_entry_rcu(found, head, list) {
1009 if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
1010 total_free_data += found->disk_total - found->disk_used;
1011 total_free_data -=
1012 btrfs_account_ro_block_groups_free_space(found);
1015 total_used += found->disk_used;
1017 rcu_read_unlock();
1019 buf->f_namelen = BTRFS_NAME_LEN;
1020 buf->f_blocks = btrfs_super_total_bytes(disk_super) >> bits;
1021 buf->f_bfree = buf->f_blocks - (total_used >> bits);
1022 buf->f_bsize = dentry->d_sb->s_blocksize;
1023 buf->f_type = BTRFS_SUPER_MAGIC;
1024 buf->f_bavail = total_free_data;
1025 ret = btrfs_calc_avail_data_space(root, &total_free_data);
1026 if (ret) {
1027 mutex_unlock(&root->fs_info->chunk_mutex);
1028 return ret;
1030 buf->f_bavail += total_free_data;
1031 buf->f_bavail = buf->f_bavail >> bits;
1032 mutex_unlock(&root->fs_info->chunk_mutex);
1034 /* We treat it as constant endianness (it doesn't matter _which_)
1035 because we want the fsid to come out the same whether mounted
1036 on a big-endian or little-endian host */
1037 buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
1038 buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
1039 /* Mask in the root object ID too, to disambiguate subvols */
1040 buf->f_fsid.val[0] ^= BTRFS_I(dentry->d_inode)->root->objectid >> 32;
1041 buf->f_fsid.val[1] ^= BTRFS_I(dentry->d_inode)->root->objectid;
1043 return 0;
1046 static struct file_system_type btrfs_fs_type = {
1047 .owner = THIS_MODULE,
1048 .name = "btrfs",
1049 .mount = btrfs_mount,
1050 .kill_sb = kill_anon_super,
1051 .fs_flags = FS_REQUIRES_DEV,
1055 * used by btrfsctl to scan devices when no FS is mounted
1057 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
1058 unsigned long arg)
1060 struct btrfs_ioctl_vol_args *vol;
1061 struct btrfs_fs_devices *fs_devices;
1062 int ret = -ENOTTY;
1064 if (!capable(CAP_SYS_ADMIN))
1065 return -EPERM;
1067 vol = memdup_user((void __user *)arg, sizeof(*vol));
1068 if (IS_ERR(vol))
1069 return PTR_ERR(vol);
1071 switch (cmd) {
1072 case BTRFS_IOC_SCAN_DEV:
1073 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
1074 &btrfs_fs_type, &fs_devices);
1075 break;
1078 kfree(vol);
1079 return ret;
1082 static int btrfs_freeze(struct super_block *sb)
1084 struct btrfs_root *root = btrfs_sb(sb);
1085 mutex_lock(&root->fs_info->transaction_kthread_mutex);
1086 mutex_lock(&root->fs_info->cleaner_mutex);
1087 return 0;
1090 static int btrfs_unfreeze(struct super_block *sb)
1092 struct btrfs_root *root = btrfs_sb(sb);
1093 mutex_unlock(&root->fs_info->cleaner_mutex);
1094 mutex_unlock(&root->fs_info->transaction_kthread_mutex);
1095 return 0;
1098 static const struct super_operations btrfs_super_ops = {
1099 .drop_inode = btrfs_drop_inode,
1100 .evict_inode = btrfs_evict_inode,
1101 .put_super = btrfs_put_super,
1102 .sync_fs = btrfs_sync_fs,
1103 .show_options = btrfs_show_options,
1104 .write_inode = btrfs_write_inode,
1105 .dirty_inode = btrfs_dirty_inode,
1106 .alloc_inode = btrfs_alloc_inode,
1107 .destroy_inode = btrfs_destroy_inode,
1108 .statfs = btrfs_statfs,
1109 .remount_fs = btrfs_remount,
1110 .freeze_fs = btrfs_freeze,
1111 .unfreeze_fs = btrfs_unfreeze,
1114 static const struct file_operations btrfs_ctl_fops = {
1115 .unlocked_ioctl = btrfs_control_ioctl,
1116 .compat_ioctl = btrfs_control_ioctl,
1117 .owner = THIS_MODULE,
1118 .llseek = noop_llseek,
1121 static struct miscdevice btrfs_misc = {
1122 .minor = BTRFS_MINOR,
1123 .name = "btrfs-control",
1124 .fops = &btrfs_ctl_fops
1127 MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
1128 MODULE_ALIAS("devname:btrfs-control");
1130 static int btrfs_interface_init(void)
1132 return misc_register(&btrfs_misc);
1135 static void btrfs_interface_exit(void)
1137 if (misc_deregister(&btrfs_misc) < 0)
1138 printk(KERN_INFO "misc_deregister failed for control device");
1141 static int __init init_btrfs_fs(void)
1143 int err;
1145 err = btrfs_init_sysfs();
1146 if (err)
1147 return err;
1149 err = btrfs_init_compress();
1150 if (err)
1151 goto free_sysfs;
1153 err = btrfs_init_cachep();
1154 if (err)
1155 goto free_compress;
1157 err = extent_io_init();
1158 if (err)
1159 goto free_cachep;
1161 err = extent_map_init();
1162 if (err)
1163 goto free_extent_io;
1165 err = btrfs_interface_init();
1166 if (err)
1167 goto free_extent_map;
1169 err = register_filesystem(&btrfs_fs_type);
1170 if (err)
1171 goto unregister_ioctl;
1173 printk(KERN_INFO "%s loaded\n", BTRFS_BUILD_VERSION);
1174 return 0;
1176 unregister_ioctl:
1177 btrfs_interface_exit();
1178 free_extent_map:
1179 extent_map_exit();
1180 free_extent_io:
1181 extent_io_exit();
1182 free_cachep:
1183 btrfs_destroy_cachep();
1184 free_compress:
1185 btrfs_exit_compress();
1186 free_sysfs:
1187 btrfs_exit_sysfs();
1188 return err;
1191 static void __exit exit_btrfs_fs(void)
1193 btrfs_destroy_cachep();
1194 extent_map_exit();
1195 extent_io_exit();
1196 btrfs_interface_exit();
1197 unregister_filesystem(&btrfs_fs_type);
1198 btrfs_exit_sysfs();
1199 btrfs_cleanup_fs_uuids();
1200 btrfs_exit_compress();
1203 module_init(init_btrfs_fs)
1204 module_exit(exit_btrfs_fs)
1206 MODULE_LICENSE("GPL");