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 "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"
54
55 #define CREATE_TRACE_POINTS
56 #include <trace/events/btrfs.h>
57
58 static const struct super_operations btrfs_super_ops;
59
btrfs_decode_error(struct btrfs_fs_info * fs_info,int errno,char nbuf[16])60 static const char *btrfs_decode_error(struct btrfs_fs_info *fs_info, int errno,
61 char nbuf[16])
62 {
63 char *errstr = NULL;
64
65 switch (errno) {
66 case -EIO:
67 errstr = "IO failure";
68 break;
69 case -ENOMEM:
70 errstr = "Out of memory";
71 break;
72 case -EROFS:
73 errstr = "Readonly filesystem";
74 break;
75 default:
76 if (nbuf) {
77 if (snprintf(nbuf, 16, "error %d", -errno) >= 0)
78 errstr = nbuf;
79 }
80 break;
81 }
82
83 return errstr;
84 }
85
__save_error_info(struct btrfs_fs_info * fs_info)86 static void __save_error_info(struct btrfs_fs_info *fs_info)
87 {
88 /*
89 * today we only save the error info into ram. Long term we'll
90 * also send it down to the disk
91 */
92 fs_info->fs_state = BTRFS_SUPER_FLAG_ERROR;
93 }
94
95 /* NOTE:
96 * We move write_super stuff at umount in order to avoid deadlock
97 * for umount hold all lock.
98 */
save_error_info(struct btrfs_fs_info * fs_info)99 static void save_error_info(struct btrfs_fs_info *fs_info)
100 {
101 __save_error_info(fs_info);
102 }
103
104 /* btrfs handle error by forcing the filesystem readonly */
btrfs_handle_error(struct btrfs_fs_info * fs_info)105 static void btrfs_handle_error(struct btrfs_fs_info *fs_info)
106 {
107 struct super_block *sb = fs_info->sb;
108
109 if (sb->s_flags & MS_RDONLY)
110 return;
111
112 if (fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
113 sb->s_flags |= MS_RDONLY;
114 printk(KERN_INFO "btrfs is forced readonly\n");
115 }
116 }
117
118 /*
119 * __btrfs_std_error decodes expected errors from the caller and
120 * invokes the approciate error response.
121 */
__btrfs_std_error(struct btrfs_fs_info * fs_info,const char * function,unsigned int line,int errno)122 void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function,
123 unsigned int line, int errno)
124 {
125 struct super_block *sb = fs_info->sb;
126 char nbuf[16];
127 const char *errstr;
128
129 /*
130 * Special case: if the error is EROFS, and we're already
131 * under MS_RDONLY, then it is safe here.
132 */
133 if (errno == -EROFS && (sb->s_flags & MS_RDONLY))
134 return;
135
136 errstr = btrfs_decode_error(fs_info, errno, nbuf);
137 printk(KERN_CRIT "BTRFS error (device %s) in %s:%d: %s\n",
138 sb->s_id, function, line, errstr);
139 save_error_info(fs_info);
140
141 btrfs_handle_error(fs_info);
142 }
143
btrfs_put_super(struct super_block * sb)144 static void btrfs_put_super(struct super_block *sb)
145 {
146 struct btrfs_root *root = btrfs_sb(sb);
147 int ret;
148
149 ret = close_ctree(root);
150 sb->s_fs_info = NULL;
151
152 (void)ret; /* FIXME: need to fix VFS to return error? */
153 }
154
155 enum {
156 Opt_degraded, Opt_subvol, Opt_subvolid, Opt_device, Opt_nodatasum,
157 Opt_nodatacow, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd,
158 Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl, Opt_compress,
159 Opt_compress_type, Opt_compress_force, Opt_compress_force_type,
160 Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard,
161 Opt_space_cache, Opt_clear_cache, Opt_user_subvol_rm_allowed,
162 Opt_enospc_debug, Opt_subvolrootid, Opt_err,
163 };
164
165 static match_table_t tokens = {
166 {Opt_degraded, "degraded"},
167 {Opt_subvol, "subvol=%s"},
168 {Opt_subvolid, "subvolid=%d"},
169 {Opt_device, "device=%s"},
170 {Opt_nodatasum, "nodatasum"},
171 {Opt_nodatacow, "nodatacow"},
172 {Opt_nobarrier, "nobarrier"},
173 {Opt_max_inline, "max_inline=%s"},
174 {Opt_alloc_start, "alloc_start=%s"},
175 {Opt_thread_pool, "thread_pool=%d"},
176 {Opt_compress, "compress"},
177 {Opt_compress_type, "compress=%s"},
178 {Opt_compress_force, "compress-force"},
179 {Opt_compress_force_type, "compress-force=%s"},
180 {Opt_ssd, "ssd"},
181 {Opt_ssd_spread, "ssd_spread"},
182 {Opt_nossd, "nossd"},
183 {Opt_noacl, "noacl"},
184 {Opt_notreelog, "notreelog"},
185 {Opt_flushoncommit, "flushoncommit"},
186 {Opt_ratio, "metadata_ratio=%d"},
187 {Opt_discard, "discard"},
188 {Opt_space_cache, "space_cache"},
189 {Opt_clear_cache, "clear_cache"},
190 {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
191 {Opt_enospc_debug, "enospc_debug"},
192 {Opt_subvolrootid, "subvolrootid=%d"},
193 {Opt_err, NULL},
194 };
195
196 /*
197 * Regular mount options parser. Everything that is needed only when
198 * reading in a new superblock is parsed here.
199 */
btrfs_parse_options(struct btrfs_root * root,char * options)200 int btrfs_parse_options(struct btrfs_root *root, char *options)
201 {
202 struct btrfs_fs_info *info = root->fs_info;
203 substring_t args[MAX_OPT_ARGS];
204 char *p, *num, *orig;
205 int intarg;
206 int ret = 0;
207 char *compress_type;
208 bool compress_force = false;
209
210 if (!options)
211 return 0;
212
213 /*
214 * strsep changes the string, duplicate it because parse_options
215 * gets called twice
216 */
217 options = kstrdup(options, GFP_NOFS);
218 if (!options)
219 return -ENOMEM;
220
221 orig = options;
222
223 while ((p = strsep(&options, ",")) != NULL) {
224 int token;
225 if (!*p)
226 continue;
227
228 token = match_token(p, tokens, args);
229 switch (token) {
230 case Opt_degraded:
231 printk(KERN_INFO "btrfs: allowing degraded mounts\n");
232 btrfs_set_opt(info->mount_opt, DEGRADED);
233 break;
234 case Opt_subvol:
235 case Opt_subvolid:
236 case Opt_subvolrootid:
237 case Opt_device:
238 /*
239 * These are parsed by btrfs_parse_early_options
240 * and can be happily ignored here.
241 */
242 break;
243 case Opt_nodatasum:
244 printk(KERN_INFO "btrfs: setting nodatasum\n");
245 btrfs_set_opt(info->mount_opt, NODATASUM);
246 break;
247 case Opt_nodatacow:
248 printk(KERN_INFO "btrfs: setting nodatacow\n");
249 btrfs_set_opt(info->mount_opt, NODATACOW);
250 btrfs_set_opt(info->mount_opt, NODATASUM);
251 break;
252 case Opt_compress_force:
253 case Opt_compress_force_type:
254 compress_force = true;
255 case Opt_compress:
256 case Opt_compress_type:
257 if (token == Opt_compress ||
258 token == Opt_compress_force ||
259 strcmp(args[0].from, "zlib") == 0) {
260 compress_type = "zlib";
261 info->compress_type = BTRFS_COMPRESS_ZLIB;
262 } else if (strcmp(args[0].from, "lzo") == 0) {
263 compress_type = "lzo";
264 info->compress_type = BTRFS_COMPRESS_LZO;
265 } else {
266 ret = -EINVAL;
267 goto out;
268 }
269
270 btrfs_set_opt(info->mount_opt, COMPRESS);
271 if (compress_force) {
272 btrfs_set_opt(info->mount_opt, FORCE_COMPRESS);
273 pr_info("btrfs: force %s compression\n",
274 compress_type);
275 } else
276 pr_info("btrfs: use %s compression\n",
277 compress_type);
278 break;
279 case Opt_ssd:
280 printk(KERN_INFO "btrfs: use ssd allocation scheme\n");
281 btrfs_set_opt(info->mount_opt, SSD);
282 break;
283 case Opt_ssd_spread:
284 printk(KERN_INFO "btrfs: use spread ssd "
285 "allocation scheme\n");
286 btrfs_set_opt(info->mount_opt, SSD);
287 btrfs_set_opt(info->mount_opt, SSD_SPREAD);
288 break;
289 case Opt_nossd:
290 printk(KERN_INFO "btrfs: not using ssd allocation "
291 "scheme\n");
292 btrfs_set_opt(info->mount_opt, NOSSD);
293 btrfs_clear_opt(info->mount_opt, SSD);
294 btrfs_clear_opt(info->mount_opt, SSD_SPREAD);
295 break;
296 case Opt_nobarrier:
297 printk(KERN_INFO "btrfs: turning off barriers\n");
298 btrfs_set_opt(info->mount_opt, NOBARRIER);
299 break;
300 case Opt_thread_pool:
301 intarg = 0;
302 match_int(&args[0], &intarg);
303 if (intarg) {
304 info->thread_pool_size = intarg;
305 printk(KERN_INFO "btrfs: thread pool %d\n",
306 info->thread_pool_size);
307 }
308 break;
309 case Opt_max_inline:
310 num = match_strdup(&args[0]);
311 if (num) {
312 info->max_inline = memparse(num, NULL);
313 kfree(num);
314
315 if (info->max_inline) {
316 info->max_inline = max_t(u64,
317 info->max_inline,
318 root->sectorsize);
319 }
320 printk(KERN_INFO "btrfs: max_inline at %llu\n",
321 (unsigned long long)info->max_inline);
322 }
323 break;
324 case Opt_alloc_start:
325 num = match_strdup(&args[0]);
326 if (num) {
327 info->alloc_start = memparse(num, NULL);
328 kfree(num);
329 printk(KERN_INFO
330 "btrfs: allocations start at %llu\n",
331 (unsigned long long)info->alloc_start);
332 }
333 break;
334 case Opt_noacl:
335 root->fs_info->sb->s_flags &= ~MS_POSIXACL;
336 break;
337 case Opt_notreelog:
338 printk(KERN_INFO "btrfs: disabling tree log\n");
339 btrfs_set_opt(info->mount_opt, NOTREELOG);
340 break;
341 case Opt_flushoncommit:
342 printk(KERN_INFO "btrfs: turning on flush-on-commit\n");
343 btrfs_set_opt(info->mount_opt, FLUSHONCOMMIT);
344 break;
345 case Opt_ratio:
346 intarg = 0;
347 match_int(&args[0], &intarg);
348 if (intarg) {
349 info->metadata_ratio = intarg;
350 printk(KERN_INFO "btrfs: metadata ratio %d\n",
351 info->metadata_ratio);
352 }
353 break;
354 case Opt_discard:
355 btrfs_set_opt(info->mount_opt, DISCARD);
356 break;
357 case Opt_space_cache:
358 printk(KERN_INFO "btrfs: enabling disk space caching\n");
359 btrfs_set_opt(info->mount_opt, SPACE_CACHE);
360 break;
361 case Opt_clear_cache:
362 printk(KERN_INFO "btrfs: force clearing of disk cache\n");
363 btrfs_set_opt(info->mount_opt, CLEAR_CACHE);
364 break;
365 case Opt_user_subvol_rm_allowed:
366 btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
367 break;
368 case Opt_enospc_debug:
369 btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
370 break;
371 case Opt_err:
372 printk(KERN_INFO "btrfs: unrecognized mount option "
373 "'%s'\n", p);
374 ret = -EINVAL;
375 goto out;
376 default:
377 break;
378 }
379 }
380 out:
381 kfree(orig);
382 return ret;
383 }
384
385 /*
386 * Parse mount options that are required early in the mount process.
387 *
388 * All other options will be parsed on much later in the mount process and
389 * only when we need to allocate a new super block.
390 */
btrfs_parse_early_options(const char * options,fmode_t flags,void * holder,char ** subvol_name,u64 * subvol_objectid,u64 * subvol_rootid,struct btrfs_fs_devices ** fs_devices)391 static int btrfs_parse_early_options(const char *options, fmode_t flags,
392 void *holder, char **subvol_name, u64 *subvol_objectid,
393 u64 *subvol_rootid, struct btrfs_fs_devices **fs_devices)
394 {
395 substring_t args[MAX_OPT_ARGS];
396 char *opts, *orig, *p;
397 int error = 0;
398 int intarg;
399
400 if (!options)
401 goto out;
402
403 /*
404 * strsep changes the string, duplicate it because parse_options
405 * gets called twice
406 */
407 opts = kstrdup(options, GFP_KERNEL);
408 if (!opts)
409 return -ENOMEM;
410 orig = opts;
411
412 while ((p = strsep(&opts, ",")) != NULL) {
413 int token;
414 if (!*p)
415 continue;
416
417 token = match_token(p, tokens, args);
418 switch (token) {
419 case Opt_subvol:
420 *subvol_name = match_strdup(&args[0]);
421 break;
422 case Opt_subvolid:
423 intarg = 0;
424 error = match_int(&args[0], &intarg);
425 if (!error) {
426 /* we want the original fs_tree */
427 if (!intarg)
428 *subvol_objectid =
429 BTRFS_FS_TREE_OBJECTID;
430 else
431 *subvol_objectid = intarg;
432 }
433 break;
434 case Opt_subvolrootid:
435 intarg = 0;
436 error = match_int(&args[0], &intarg);
437 if (!error) {
438 /* we want the original fs_tree */
439 if (!intarg)
440 *subvol_rootid =
441 BTRFS_FS_TREE_OBJECTID;
442 else
443 *subvol_rootid = intarg;
444 }
445 break;
446 case Opt_device:
447 error = btrfs_scan_one_device(match_strdup(&args[0]),
448 flags, holder, fs_devices);
449 if (error)
450 goto out_free_opts;
451 break;
452 default:
453 break;
454 }
455 }
456
457 out_free_opts:
458 kfree(orig);
459 out:
460 /*
461 * If no subvolume name is specified we use the default one. Allocate
462 * a copy of the string "." here so that code later in the
463 * mount path doesn't care if it's the default volume or another one.
464 */
465 if (!*subvol_name) {
466 *subvol_name = kstrdup(".", GFP_KERNEL);
467 if (!*subvol_name)
468 return -ENOMEM;
469 }
470 return error;
471 }
472
get_default_root(struct super_block * sb,u64 subvol_objectid)473 static struct dentry *get_default_root(struct super_block *sb,
474 u64 subvol_objectid)
475 {
476 struct btrfs_root *root = sb->s_fs_info;
477 struct btrfs_root *new_root;
478 struct btrfs_dir_item *di;
479 struct btrfs_path *path;
480 struct btrfs_key location;
481 struct inode *inode;
482 struct dentry *dentry;
483 u64 dir_id;
484 int new = 0;
485
486 /*
487 * We have a specific subvol we want to mount, just setup location and
488 * go look up the root.
489 */
490 if (subvol_objectid) {
491 location.objectid = subvol_objectid;
492 location.type = BTRFS_ROOT_ITEM_KEY;
493 location.offset = (u64)-1;
494 goto find_root;
495 }
496
497 path = btrfs_alloc_path();
498 if (!path)
499 return ERR_PTR(-ENOMEM);
500 path->leave_spinning = 1;
501
502 /*
503 * Find the "default" dir item which points to the root item that we
504 * will mount by default if we haven't been given a specific subvolume
505 * to mount.
506 */
507 dir_id = btrfs_super_root_dir(&root->fs_info->super_copy);
508 di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
509 if (IS_ERR(di))
510 return ERR_CAST(di);
511 if (!di) {
512 /*
513 * Ok the default dir item isn't there. This is weird since
514 * it's always been there, but don't freak out, just try and
515 * mount to root most subvolume.
516 */
517 btrfs_free_path(path);
518 dir_id = BTRFS_FIRST_FREE_OBJECTID;
519 new_root = root->fs_info->fs_root;
520 goto setup_root;
521 }
522
523 btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
524 btrfs_free_path(path);
525
526 find_root:
527 new_root = btrfs_read_fs_root_no_name(root->fs_info, &location);
528 if (IS_ERR(new_root))
529 return ERR_CAST(new_root);
530
531 if (btrfs_root_refs(&new_root->root_item) == 0)
532 return ERR_PTR(-ENOENT);
533
534 dir_id = btrfs_root_dirid(&new_root->root_item);
535 setup_root:
536 location.objectid = dir_id;
537 location.type = BTRFS_INODE_ITEM_KEY;
538 location.offset = 0;
539
540 inode = btrfs_iget(sb, &location, new_root, &new);
541 if (IS_ERR(inode))
542 return ERR_CAST(inode);
543
544 /*
545 * If we're just mounting the root most subvol put the inode and return
546 * a reference to the dentry. We will have already gotten a reference
547 * to the inode in btrfs_fill_super so we're good to go.
548 */
549 if (!new && sb->s_root->d_inode == inode) {
550 iput(inode);
551 return dget(sb->s_root);
552 }
553
554 if (new) {
555 const struct qstr name = { .name = "/", .len = 1 };
556
557 /*
558 * New inode, we need to make the dentry a sibling of s_root so
559 * everything gets cleaned up properly on unmount.
560 */
561 dentry = d_alloc(sb->s_root, &name);
562 if (!dentry) {
563 iput(inode);
564 return ERR_PTR(-ENOMEM);
565 }
566 d_splice_alias(inode, dentry);
567 } else {
568 /*
569 * We found the inode in cache, just find a dentry for it and
570 * put the reference to the inode we just got.
571 */
572 dentry = d_find_alias(inode);
573 iput(inode);
574 }
575
576 return dentry;
577 }
578
btrfs_fill_super(struct super_block * sb,struct btrfs_fs_devices * fs_devices,void * data,int silent)579 static int btrfs_fill_super(struct super_block *sb,
580 struct btrfs_fs_devices *fs_devices,
581 void *data, int silent)
582 {
583 struct inode *inode;
584 struct dentry *root_dentry;
585 struct btrfs_root *tree_root;
586 struct btrfs_key key;
587 int err;
588
589 sb->s_maxbytes = MAX_LFS_FILESIZE;
590 sb->s_magic = BTRFS_SUPER_MAGIC;
591 sb->s_op = &btrfs_super_ops;
592 sb->s_d_op = &btrfs_dentry_operations;
593 sb->s_export_op = &btrfs_export_ops;
594 sb->s_xattr = btrfs_xattr_handlers;
595 sb->s_time_gran = 1;
596 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
597 sb->s_flags |= MS_POSIXACL;
598 #endif
599
600 tree_root = open_ctree(sb, fs_devices, (char *)data);
601
602 if (IS_ERR(tree_root)) {
603 printk("btrfs: open_ctree failed\n");
604 return PTR_ERR(tree_root);
605 }
606 sb->s_fs_info = tree_root;
607
608 key.objectid = BTRFS_FIRST_FREE_OBJECTID;
609 key.type = BTRFS_INODE_ITEM_KEY;
610 key.offset = 0;
611 inode = btrfs_iget(sb, &key, tree_root->fs_info->fs_root, NULL);
612 if (IS_ERR(inode)) {
613 err = PTR_ERR(inode);
614 goto fail_close;
615 }
616
617 root_dentry = d_alloc_root(inode);
618 if (!root_dentry) {
619 iput(inode);
620 err = -ENOMEM;
621 goto fail_close;
622 }
623
624 sb->s_root = root_dentry;
625
626 save_mount_options(sb, data);
627 return 0;
628
629 fail_close:
630 close_ctree(tree_root);
631 return err;
632 }
633
btrfs_sync_fs(struct super_block * sb,int wait)634 int btrfs_sync_fs(struct super_block *sb, int wait)
635 {
636 struct btrfs_trans_handle *trans;
637 struct btrfs_root *root = btrfs_sb(sb);
638 int ret;
639
640 trace_btrfs_sync_fs(wait);
641
642 if (!wait) {
643 filemap_flush(root->fs_info->btree_inode->i_mapping);
644 return 0;
645 }
646
647 btrfs_start_delalloc_inodes(root, 0);
648 btrfs_wait_ordered_extents(root, 0, 0);
649
650 trans = btrfs_start_transaction(root, 0);
651 if (IS_ERR(trans))
652 return PTR_ERR(trans);
653 ret = btrfs_commit_transaction(trans, root);
654 return ret;
655 }
656
btrfs_show_options(struct seq_file * seq,struct vfsmount * vfs)657 static int btrfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
658 {
659 struct btrfs_root *root = btrfs_sb(vfs->mnt_sb);
660 struct btrfs_fs_info *info = root->fs_info;
661 char *compress_type;
662
663 if (btrfs_test_opt(root, DEGRADED))
664 seq_puts(seq, ",degraded");
665 if (btrfs_test_opt(root, NODATASUM))
666 seq_puts(seq, ",nodatasum");
667 if (btrfs_test_opt(root, NODATACOW))
668 seq_puts(seq, ",nodatacow");
669 if (btrfs_test_opt(root, NOBARRIER))
670 seq_puts(seq, ",nobarrier");
671 if (info->max_inline != 8192 * 1024)
672 seq_printf(seq, ",max_inline=%llu",
673 (unsigned long long)info->max_inline);
674 if (info->alloc_start != 0)
675 seq_printf(seq, ",alloc_start=%llu",
676 (unsigned long long)info->alloc_start);
677 if (info->thread_pool_size != min_t(unsigned long,
678 num_online_cpus() + 2, 8))
679 seq_printf(seq, ",thread_pool=%d", info->thread_pool_size);
680 if (btrfs_test_opt(root, COMPRESS)) {
681 if (info->compress_type == BTRFS_COMPRESS_ZLIB)
682 compress_type = "zlib";
683 else
684 compress_type = "lzo";
685 if (btrfs_test_opt(root, FORCE_COMPRESS))
686 seq_printf(seq, ",compress-force=%s", compress_type);
687 else
688 seq_printf(seq, ",compress=%s", compress_type);
689 }
690 if (btrfs_test_opt(root, NOSSD))
691 seq_puts(seq, ",nossd");
692 if (btrfs_test_opt(root, SSD_SPREAD))
693 seq_puts(seq, ",ssd_spread");
694 else if (btrfs_test_opt(root, SSD))
695 seq_puts(seq, ",ssd");
696 if (btrfs_test_opt(root, NOTREELOG))
697 seq_puts(seq, ",notreelog");
698 if (btrfs_test_opt(root, FLUSHONCOMMIT))
699 seq_puts(seq, ",flushoncommit");
700 if (btrfs_test_opt(root, DISCARD))
701 seq_puts(seq, ",discard");
702 if (!(root->fs_info->sb->s_flags & MS_POSIXACL))
703 seq_puts(seq, ",noacl");
704 if (btrfs_test_opt(root, SPACE_CACHE))
705 seq_puts(seq, ",space_cache");
706 if (btrfs_test_opt(root, CLEAR_CACHE))
707 seq_puts(seq, ",clear_cache");
708 if (btrfs_test_opt(root, USER_SUBVOL_RM_ALLOWED))
709 seq_puts(seq, ",user_subvol_rm_allowed");
710 return 0;
711 }
712
btrfs_test_super(struct super_block * s,void * data)713 static int btrfs_test_super(struct super_block *s, void *data)
714 {
715 struct btrfs_root *test_root = data;
716 struct btrfs_root *root = btrfs_sb(s);
717
718 /*
719 * If this super block is going away, return false as it
720 * can't match as an existing super block.
721 */
722 if (!atomic_read(&s->s_active))
723 return 0;
724 return root->fs_info->fs_devices == test_root->fs_info->fs_devices;
725 }
726
btrfs_set_super(struct super_block * s,void * data)727 static int btrfs_set_super(struct super_block *s, void *data)
728 {
729 s->s_fs_info = data;
730
731 return set_anon_super(s, data);
732 }
733
734
735 /*
736 * Find a superblock for the given device / mount point.
737 *
738 * Note: This is based on get_sb_bdev from fs/super.c with a few additions
739 * for multiple device setup. Make sure to keep it in sync.
740 */
btrfs_mount(struct file_system_type * fs_type,int flags,const char * dev_name,void * data)741 static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
742 const char *dev_name, void *data)
743 {
744 struct block_device *bdev = NULL;
745 struct super_block *s;
746 struct dentry *root;
747 struct btrfs_fs_devices *fs_devices = NULL;
748 struct btrfs_root *tree_root = NULL;
749 struct btrfs_fs_info *fs_info = NULL;
750 fmode_t mode = FMODE_READ;
751 char *subvol_name = NULL;
752 u64 subvol_objectid = 0;
753 u64 subvol_rootid = 0;
754 int error = 0;
755
756 if (!(flags & MS_RDONLY))
757 mode |= FMODE_WRITE;
758
759 error = btrfs_parse_early_options(data, mode, fs_type,
760 &subvol_name, &subvol_objectid,
761 &subvol_rootid, &fs_devices);
762 if (error)
763 return ERR_PTR(error);
764
765 error = btrfs_scan_one_device(dev_name, mode, fs_type, &fs_devices);
766 if (error)
767 goto error_free_subvol_name;
768
769 error = btrfs_open_devices(fs_devices, mode, fs_type);
770 if (error)
771 goto error_free_subvol_name;
772
773 if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
774 error = -EACCES;
775 goto error_close_devices;
776 }
777
778 /*
779 * Setup a dummy root and fs_info for test/set super. This is because
780 * we don't actually fill this stuff out until open_ctree, but we need
781 * it for searching for existing supers, so this lets us do that and
782 * then open_ctree will properly initialize everything later.
783 */
784 fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_NOFS);
785 tree_root = kzalloc(sizeof(struct btrfs_root), GFP_NOFS);
786 if (!fs_info || !tree_root) {
787 error = -ENOMEM;
788 goto error_close_devices;
789 }
790 fs_info->tree_root = tree_root;
791 fs_info->fs_devices = fs_devices;
792 tree_root->fs_info = fs_info;
793
794 bdev = fs_devices->latest_bdev;
795 s = sget(fs_type, btrfs_test_super, btrfs_set_super, tree_root);
796 if (IS_ERR(s))
797 goto error_s;
798
799 if (s->s_root) {
800 if ((flags ^ s->s_flags) & MS_RDONLY) {
801 deactivate_locked_super(s);
802 error = -EBUSY;
803 goto error_close_devices;
804 }
805
806 btrfs_close_devices(fs_devices);
807 kfree(fs_info);
808 kfree(tree_root);
809 } else {
810 char b[BDEVNAME_SIZE];
811
812 s->s_flags = flags;
813 strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
814 error = btrfs_fill_super(s, fs_devices, data,
815 flags & MS_SILENT ? 1 : 0);
816 if (error) {
817 deactivate_locked_super(s);
818 goto error_free_subvol_name;
819 }
820
821 btrfs_sb(s)->fs_info->bdev_holder = fs_type;
822 s->s_flags |= MS_ACTIVE;
823 }
824
825 /* if they gave us a subvolume name bind mount into that */
826 if (strcmp(subvol_name, ".")) {
827 struct dentry *new_root;
828
829 root = get_default_root(s, subvol_rootid);
830 if (IS_ERR(root)) {
831 error = PTR_ERR(root);
832 deactivate_locked_super(s);
833 goto error_free_subvol_name;
834 }
835
836 mutex_lock(&root->d_inode->i_mutex);
837 new_root = lookup_one_len(subvol_name, root,
838 strlen(subvol_name));
839 mutex_unlock(&root->d_inode->i_mutex);
840
841 if (IS_ERR(new_root)) {
842 dput(root);
843 deactivate_locked_super(s);
844 error = PTR_ERR(new_root);
845 goto error_free_subvol_name;
846 }
847 if (!new_root->d_inode) {
848 dput(root);
849 dput(new_root);
850 deactivate_locked_super(s);
851 error = -ENXIO;
852 goto error_free_subvol_name;
853 }
854 dput(root);
855 root = new_root;
856 } else {
857 root = get_default_root(s, subvol_objectid);
858 if (IS_ERR(root)) {
859 error = PTR_ERR(root);
860 deactivate_locked_super(s);
861 goto error_free_subvol_name;
862 }
863 }
864
865 kfree(subvol_name);
866 return root;
867
868 error_s:
869 error = PTR_ERR(s);
870 error_close_devices:
871 btrfs_close_devices(fs_devices);
872 kfree(fs_info);
873 kfree(tree_root);
874 error_free_subvol_name:
875 kfree(subvol_name);
876 return ERR_PTR(error);
877 }
878
btrfs_remount(struct super_block * sb,int * flags,char * data)879 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
880 {
881 struct btrfs_root *root = btrfs_sb(sb);
882 int ret;
883
884 ret = btrfs_parse_options(root, data);
885 if (ret)
886 return -EINVAL;
887
888 if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
889 return 0;
890
891 if (*flags & MS_RDONLY) {
892 sb->s_flags |= MS_RDONLY;
893
894 ret = btrfs_commit_super(root);
895 WARN_ON(ret);
896 } else {
897 if (root->fs_info->fs_devices->rw_devices == 0)
898 return -EACCES;
899
900 if (btrfs_super_log_root(&root->fs_info->super_copy) != 0)
901 return -EINVAL;
902
903 ret = btrfs_cleanup_fs_roots(root->fs_info);
904 WARN_ON(ret);
905
906 /* recover relocation */
907 ret = btrfs_recover_relocation(root);
908 WARN_ON(ret);
909
910 sb->s_flags &= ~MS_RDONLY;
911 }
912
913 return 0;
914 }
915
916 /*
917 * The helper to calc the free space on the devices that can be used to store
918 * file data.
919 */
btrfs_calc_avail_data_space(struct btrfs_root * root,u64 * free_bytes)920 static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes)
921 {
922 struct btrfs_fs_info *fs_info = root->fs_info;
923 struct btrfs_device_info *devices_info;
924 struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
925 struct btrfs_device *device;
926 u64 skip_space;
927 u64 type;
928 u64 avail_space;
929 u64 used_space;
930 u64 min_stripe_size;
931 int min_stripes = 1;
932 int i = 0, nr_devices;
933 int ret;
934
935 nr_devices = fs_info->fs_devices->rw_devices;
936 BUG_ON(!nr_devices);
937
938 devices_info = kmalloc(sizeof(*devices_info) * nr_devices,
939 GFP_NOFS);
940 if (!devices_info)
941 return -ENOMEM;
942
943 /* calc min stripe number for data space alloction */
944 type = btrfs_get_alloc_profile(root, 1);
945 if (type & BTRFS_BLOCK_GROUP_RAID0)
946 min_stripes = 2;
947 else if (type & BTRFS_BLOCK_GROUP_RAID1)
948 min_stripes = 2;
949 else if (type & BTRFS_BLOCK_GROUP_RAID10)
950 min_stripes = 4;
951
952 if (type & BTRFS_BLOCK_GROUP_DUP)
953 min_stripe_size = 2 * BTRFS_STRIPE_LEN;
954 else
955 min_stripe_size = BTRFS_STRIPE_LEN;
956
957 list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
958 if (!device->in_fs_metadata)
959 continue;
960
961 avail_space = device->total_bytes - device->bytes_used;
962
963 /* align with stripe_len */
964 do_div(avail_space, BTRFS_STRIPE_LEN);
965 avail_space *= BTRFS_STRIPE_LEN;
966
967 /*
968 * In order to avoid overwritting the superblock on the drive,
969 * btrfs starts at an offset of at least 1MB when doing chunk
970 * allocation.
971 */
972 skip_space = 1024 * 1024;
973
974 /* user can set the offset in fs_info->alloc_start. */
975 if (fs_info->alloc_start + BTRFS_STRIPE_LEN <=
976 device->total_bytes)
977 skip_space = max(fs_info->alloc_start, skip_space);
978
979 /*
980 * btrfs can not use the free space in [0, skip_space - 1],
981 * we must subtract it from the total. In order to implement
982 * it, we account the used space in this range first.
983 */
984 ret = btrfs_account_dev_extents_size(device, 0, skip_space - 1,
985 &used_space);
986 if (ret) {
987 kfree(devices_info);
988 return ret;
989 }
990
991 /* calc the free space in [0, skip_space - 1] */
992 skip_space -= used_space;
993
994 /*
995 * we can use the free space in [0, skip_space - 1], subtract
996 * it from the total.
997 */
998 if (avail_space && avail_space >= skip_space)
999 avail_space -= skip_space;
1000 else
1001 avail_space = 0;
1002
1003 if (avail_space < min_stripe_size)
1004 continue;
1005
1006 devices_info[i].dev = device;
1007 devices_info[i].max_avail = avail_space;
1008
1009 i++;
1010 }
1011
1012 nr_devices = i;
1013
1014 btrfs_descending_sort_devices(devices_info, nr_devices);
1015
1016 i = nr_devices - 1;
1017 avail_space = 0;
1018 while (nr_devices >= min_stripes) {
1019 if (devices_info[i].max_avail >= min_stripe_size) {
1020 int j;
1021 u64 alloc_size;
1022
1023 avail_space += devices_info[i].max_avail * min_stripes;
1024 alloc_size = devices_info[i].max_avail;
1025 for (j = i + 1 - min_stripes; j <= i; j++)
1026 devices_info[j].max_avail -= alloc_size;
1027 }
1028 i--;
1029 nr_devices--;
1030 }
1031
1032 kfree(devices_info);
1033 *free_bytes = avail_space;
1034 return 0;
1035 }
1036
btrfs_statfs(struct dentry * dentry,struct kstatfs * buf)1037 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
1038 {
1039 struct btrfs_root *root = btrfs_sb(dentry->d_sb);
1040 struct btrfs_super_block *disk_super = &root->fs_info->super_copy;
1041 struct list_head *head = &root->fs_info->space_info;
1042 struct btrfs_space_info *found;
1043 u64 total_used = 0;
1044 u64 total_free_data = 0;
1045 int bits = dentry->d_sb->s_blocksize_bits;
1046 __be32 *fsid = (__be32 *)root->fs_info->fsid;
1047 int ret;
1048
1049 /* holding chunk_muext to avoid allocating new chunks */
1050 mutex_lock(&root->fs_info->chunk_mutex);
1051 rcu_read_lock();
1052 list_for_each_entry_rcu(found, head, list) {
1053 if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
1054 total_free_data += found->disk_total - found->disk_used;
1055 total_free_data -=
1056 btrfs_account_ro_block_groups_free_space(found);
1057 }
1058
1059 total_used += found->disk_used;
1060 }
1061 rcu_read_unlock();
1062
1063 buf->f_namelen = BTRFS_NAME_LEN;
1064 buf->f_blocks = btrfs_super_total_bytes(disk_super) >> bits;
1065 buf->f_bfree = buf->f_blocks - (total_used >> bits);
1066 buf->f_bsize = dentry->d_sb->s_blocksize;
1067 buf->f_type = BTRFS_SUPER_MAGIC;
1068 buf->f_bavail = total_free_data;
1069 ret = btrfs_calc_avail_data_space(root, &total_free_data);
1070 if (ret) {
1071 mutex_unlock(&root->fs_info->chunk_mutex);
1072 return ret;
1073 }
1074 buf->f_bavail += total_free_data;
1075 buf->f_bavail = buf->f_bavail >> bits;
1076 mutex_unlock(&root->fs_info->chunk_mutex);
1077
1078 /* We treat it as constant endianness (it doesn't matter _which_)
1079 because we want the fsid to come out the same whether mounted
1080 on a big-endian or little-endian host */
1081 buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
1082 buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
1083 /* Mask in the root object ID too, to disambiguate subvols */
1084 buf->f_fsid.val[0] ^= BTRFS_I(dentry->d_inode)->root->objectid >> 32;
1085 buf->f_fsid.val[1] ^= BTRFS_I(dentry->d_inode)->root->objectid;
1086
1087 return 0;
1088 }
1089
1090 static struct file_system_type btrfs_fs_type = {
1091 .owner = THIS_MODULE,
1092 .name = "btrfs",
1093 .mount = btrfs_mount,
1094 .kill_sb = kill_anon_super,
1095 .fs_flags = FS_REQUIRES_DEV,
1096 };
1097
1098 /*
1099 * used by btrfsctl to scan devices when no FS is mounted
1100 */
btrfs_control_ioctl(struct file * file,unsigned int cmd,unsigned long arg)1101 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
1102 unsigned long arg)
1103 {
1104 struct btrfs_ioctl_vol_args *vol;
1105 struct btrfs_fs_devices *fs_devices;
1106 int ret = -ENOTTY;
1107
1108 if (!capable(CAP_SYS_ADMIN))
1109 return -EPERM;
1110
1111 vol = memdup_user((void __user *)arg, sizeof(*vol));
1112 if (IS_ERR(vol))
1113 return PTR_ERR(vol);
1114
1115 switch (cmd) {
1116 case BTRFS_IOC_SCAN_DEV:
1117 ret = btrfs_scan_one_device(vol->name, FMODE_READ,
1118 &btrfs_fs_type, &fs_devices);
1119 break;
1120 }
1121
1122 kfree(vol);
1123 return ret;
1124 }
1125
btrfs_freeze(struct super_block * sb)1126 static int btrfs_freeze(struct super_block *sb)
1127 {
1128 struct btrfs_root *root = btrfs_sb(sb);
1129 mutex_lock(&root->fs_info->transaction_kthread_mutex);
1130 mutex_lock(&root->fs_info->cleaner_mutex);
1131 return 0;
1132 }
1133
btrfs_unfreeze(struct super_block * sb)1134 static int btrfs_unfreeze(struct super_block *sb)
1135 {
1136 struct btrfs_root *root = btrfs_sb(sb);
1137 mutex_unlock(&root->fs_info->cleaner_mutex);
1138 mutex_unlock(&root->fs_info->transaction_kthread_mutex);
1139 return 0;
1140 }
1141
1142 static const struct super_operations btrfs_super_ops = {
1143 .drop_inode = btrfs_drop_inode,
1144 .evict_inode = btrfs_evict_inode,
1145 .put_super = btrfs_put_super,
1146 .sync_fs = btrfs_sync_fs,
1147 .show_options = btrfs_show_options,
1148 .write_inode = btrfs_write_inode,
1149 .dirty_inode = btrfs_dirty_inode,
1150 .alloc_inode = btrfs_alloc_inode,
1151 .destroy_inode = btrfs_destroy_inode,
1152 .statfs = btrfs_statfs,
1153 .remount_fs = btrfs_remount,
1154 .freeze_fs = btrfs_freeze,
1155 .unfreeze_fs = btrfs_unfreeze,
1156 };
1157
1158 static const struct file_operations btrfs_ctl_fops = {
1159 .unlocked_ioctl = btrfs_control_ioctl,
1160 .compat_ioctl = btrfs_control_ioctl,
1161 .owner = THIS_MODULE,
1162 .llseek = noop_llseek,
1163 };
1164
1165 static struct miscdevice btrfs_misc = {
1166 .minor = BTRFS_MINOR,
1167 .name = "btrfs-control",
1168 .fops = &btrfs_ctl_fops
1169 };
1170
1171 MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
1172 MODULE_ALIAS("devname:btrfs-control");
1173
btrfs_interface_init(void)1174 static int btrfs_interface_init(void)
1175 {
1176 return misc_register(&btrfs_misc);
1177 }
1178
btrfs_interface_exit(void)1179 static void btrfs_interface_exit(void)
1180 {
1181 if (misc_deregister(&btrfs_misc) < 0)
1182 printk(KERN_INFO "misc_deregister failed for control device");
1183 }
1184
init_btrfs_fs(void)1185 static int __init init_btrfs_fs(void)
1186 {
1187 int err;
1188
1189 err = btrfs_init_sysfs();
1190 if (err)
1191 return err;
1192
1193 err = btrfs_init_compress();
1194 if (err)
1195 goto free_sysfs;
1196
1197 err = btrfs_init_cachep();
1198 if (err)
1199 goto free_compress;
1200
1201 err = extent_io_init();
1202 if (err)
1203 goto free_cachep;
1204
1205 err = extent_map_init();
1206 if (err)
1207 goto free_extent_io;
1208
1209 err = btrfs_interface_init();
1210 if (err)
1211 goto free_extent_map;
1212
1213 err = register_filesystem(&btrfs_fs_type);
1214 if (err)
1215 goto unregister_ioctl;
1216
1217 printk(KERN_INFO "%s loaded\n", BTRFS_BUILD_VERSION);
1218 return 0;
1219
1220 unregister_ioctl:
1221 btrfs_interface_exit();
1222 free_extent_map:
1223 extent_map_exit();
1224 free_extent_io:
1225 extent_io_exit();
1226 free_cachep:
1227 btrfs_destroy_cachep();
1228 free_compress:
1229 btrfs_exit_compress();
1230 free_sysfs:
1231 btrfs_exit_sysfs();
1232 return err;
1233 }
1234
exit_btrfs_fs(void)1235 static void __exit exit_btrfs_fs(void)
1236 {
1237 btrfs_destroy_cachep();
1238 extent_map_exit();
1239 extent_io_exit();
1240 btrfs_interface_exit();
1241 unregister_filesystem(&btrfs_fs_type);
1242 btrfs_exit_sysfs();
1243 btrfs_cleanup_fs_uuids();
1244 btrfs_exit_compress();
1245 }
1246
1247 module_init(init_btrfs_fs)
1248 module_exit(exit_btrfs_fs)
1249
1250 MODULE_LICENSE("GPL");
1251