Add /dev/btrfs-control for device scanning ioctls
[linux-2.6] / fs / btrfs / super.c
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/string.h>
28 #include <linux/smp_lock.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 "ctree.h"
41 #include "disk-io.h"
42 #include "transaction.h"
43 #include "btrfs_inode.h"
44 #include "ioctl.h"
45 #include "print-tree.h"
46 #include "xattr.h"
47
48 #define BTRFS_SUPER_MAGIC 0x9123683E
49
50 static struct super_operations btrfs_super_ops;
51
52 static void btrfs_put_super (struct super_block * sb)
53 {
54         struct btrfs_root *root = btrfs_sb(sb);
55         struct btrfs_fs_info *fs = root->fs_info;
56         int ret;
57
58         ret = close_ctree(root);
59         if (ret) {
60                 printk("close ctree returns %d\n", ret);
61         }
62         btrfs_sysfs_del_super(fs);
63         sb->s_fs_info = NULL;
64 }
65
66 enum {
67         Opt_subvol, Opt_nodatasum, Opt_nodatacow, Opt_max_extent,
68         Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd, Opt_err,
69 };
70
71 static match_table_t tokens = {
72         {Opt_subvol, "subvol=%s"},
73         {Opt_nodatasum, "nodatasum"},
74         {Opt_nodatacow, "nodatacow"},
75         {Opt_nobarrier, "nobarrier"},
76         {Opt_max_extent, "max_extent=%s"},
77         {Opt_max_inline, "max_inline=%s"},
78         {Opt_alloc_start, "alloc_start=%s"},
79         {Opt_ssd, "ssd"},
80         {Opt_err, NULL}
81 };
82
83 u64 btrfs_parse_size(char *str)
84 {
85         u64 res;
86         int mult = 1;
87         char *end;
88         char last;
89
90         res = simple_strtoul(str, &end, 10);
91
92         last = end[0];
93         if (isalpha(last)) {
94                 last = tolower(last);
95                 switch (last) {
96                 case 'g':
97                         mult *= 1024;
98                 case 'm':
99                         mult *= 1024;
100                 case 'k':
101                         mult *= 1024;
102                 }
103                 res = res * mult;
104         }
105         return res;
106 }
107
108 static int parse_options (char * options,
109                           struct btrfs_root *root,
110                           char **subvol_name)
111 {
112         char * p;
113         struct btrfs_fs_info *info = NULL;
114         substring_t args[MAX_OPT_ARGS];
115
116         if (!options)
117                 return 1;
118
119         /*
120          * strsep changes the string, duplicate it because parse_options
121          * gets called twice
122          */
123         options = kstrdup(options, GFP_NOFS);
124         if (!options)
125                 return -ENOMEM;
126
127         if (root)
128                 info = root->fs_info;
129
130         while ((p = strsep (&options, ",")) != NULL) {
131                 int token;
132                 if (!*p)
133                         continue;
134
135                 token = match_token(p, tokens, args);
136                 switch (token) {
137                 case Opt_subvol:
138                         if (subvol_name) {
139                                 *subvol_name = match_strdup(&args[0]);
140                         }
141                         break;
142                 case Opt_nodatasum:
143                         if (info) {
144                                 printk("btrfs: setting nodatacsum\n");
145                                 btrfs_set_opt(info->mount_opt, NODATASUM);
146                         }
147                         break;
148                 case Opt_nodatacow:
149                         if (info) {
150                                 printk("btrfs: setting nodatacow\n");
151                                 btrfs_set_opt(info->mount_opt, NODATACOW);
152                                 btrfs_set_opt(info->mount_opt, NODATASUM);
153                         }
154                         break;
155                 case Opt_ssd:
156                         if (info) {
157                                 printk("btrfs: use ssd allocation scheme\n");
158                                 btrfs_set_opt(info->mount_opt, SSD);
159                         }
160                         break;
161                 case Opt_nobarrier:
162                         if (info) {
163                                 printk("btrfs: turning off barriers\n");
164                                 btrfs_set_opt(info->mount_opt, NOBARRIER);
165                         }
166                         break;
167                 case Opt_max_extent:
168                         if (info) {
169                                 char *num = match_strdup(&args[0]);
170                                 if (num) {
171                                         info->max_extent =
172                                                 btrfs_parse_size(num);
173                                         kfree(num);
174
175                                         info->max_extent = max_t(u64,
176                                                          info->max_extent,
177                                                          root->sectorsize);
178                                         printk("btrfs: max_extent at %Lu\n",
179                                                info->max_extent);
180                                 }
181                         }
182                         break;
183                 case Opt_max_inline:
184                         if (info) {
185                                 char *num = match_strdup(&args[0]);
186                                 if (num) {
187                                         info->max_inline =
188                                                 btrfs_parse_size(num);
189                                         kfree(num);
190
191                                         info->max_inline = max_t(u64,
192                                                          info->max_inline,
193                                                          root->sectorsize);
194                                         printk("btrfs: max_inline at %Lu\n",
195                                                info->max_inline);
196                                 }
197                         }
198                         break;
199                 case Opt_alloc_start:
200                         if (info) {
201                                 char *num = match_strdup(&args[0]);
202                                 if (num) {
203                                         info->alloc_start =
204                                                 btrfs_parse_size(num);
205                                         kfree(num);
206                                         printk("btrfs: allocations start at "
207                                                "%Lu\n", info->alloc_start);
208                                 }
209                         }
210                         break;
211                 default:
212                         break;
213                 }
214         }
215         kfree(options);
216         return 1;
217 }
218
219 static int btrfs_fill_super(struct super_block * sb, void * data, int silent)
220 {
221         struct inode * inode;
222         struct dentry * root_dentry;
223         struct btrfs_super_block *disk_super;
224         struct btrfs_root *tree_root;
225         struct btrfs_inode *bi;
226         int err;
227
228         sb->s_maxbytes = MAX_LFS_FILESIZE;
229         sb->s_magic = BTRFS_SUPER_MAGIC;
230         sb->s_op = &btrfs_super_ops;
231         sb->s_xattr = btrfs_xattr_handlers;
232         sb->s_time_gran = 1;
233
234         tree_root = open_ctree(sb);
235
236         if (!tree_root || IS_ERR(tree_root)) {
237                 printk("btrfs: open_ctree failed\n");
238                 return -EIO;
239         }
240         sb->s_fs_info = tree_root;
241         disk_super = &tree_root->fs_info->super_copy;
242         inode = btrfs_iget_locked(sb, btrfs_super_root_dir(disk_super),
243                                   tree_root);
244         bi = BTRFS_I(inode);
245         bi->location.objectid = inode->i_ino;
246         bi->location.offset = 0;
247         bi->root = tree_root;
248
249         btrfs_set_key_type(&bi->location, BTRFS_INODE_ITEM_KEY);
250
251         if (!inode) {
252                 err = -ENOMEM;
253                 goto fail_close;
254         }
255         if (inode->i_state & I_NEW) {
256                 btrfs_read_locked_inode(inode);
257                 unlock_new_inode(inode);
258         }
259
260         root_dentry = d_alloc_root(inode);
261         if (!root_dentry) {
262                 iput(inode);
263                 err = -ENOMEM;
264                 goto fail_close;
265         }
266
267         parse_options((char *)data, tree_root, NULL);
268
269         /* this does the super kobj at the same time */
270         err = btrfs_sysfs_add_super(tree_root->fs_info);
271         if (err)
272                 goto fail_close;
273
274         sb->s_root = root_dentry;
275         btrfs_transaction_queue_work(tree_root, HZ * 30);
276
277 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,25)
278         save_mount_options(sb, data);
279 #endif
280
281         return 0;
282
283 fail_close:
284         close_ctree(tree_root);
285         return err;
286 }
287
288 static int btrfs_sync_fs(struct super_block *sb, int wait)
289 {
290         struct btrfs_trans_handle *trans;
291         struct btrfs_root *root;
292         int ret;
293         root = btrfs_sb(sb);
294
295         sb->s_dirt = 0;
296         if (!wait) {
297                 filemap_flush(root->fs_info->btree_inode->i_mapping);
298                 return 0;
299         }
300         btrfs_clean_old_snapshots(root);
301         mutex_lock(&root->fs_info->fs_mutex);
302         btrfs_defrag_dirty_roots(root->fs_info);
303         trans = btrfs_start_transaction(root, 1);
304         ret = btrfs_commit_transaction(trans, root);
305         sb->s_dirt = 0;
306         mutex_unlock(&root->fs_info->fs_mutex);
307         return ret;
308 }
309
310 static void btrfs_write_super(struct super_block *sb)
311 {
312         sb->s_dirt = 0;
313 }
314
315 /*
316  * This is almost a copy of get_sb_bdev in fs/super.c.
317  * We need the local copy to allow direct mounting of
318  * subvolumes, but this could be easily integrated back
319  * into the generic version.  --hch
320  */
321
322 /* start copy & paste */
323 static int set_bdev_super(struct super_block *s, void *data)
324 {
325         s->s_bdev = data;
326         s->s_dev = s->s_bdev->bd_dev;
327         return 0;
328 }
329
330 static int test_bdev_super(struct super_block *s, void *data)
331 {
332         return (void *)s->s_bdev == data;
333 }
334
335 int btrfs_get_sb_bdev(struct file_system_type *fs_type,
336         int flags, const char *dev_name, void *data,
337         int (*fill_super)(struct super_block *, void *, int),
338         struct vfsmount *mnt, const char *subvol)
339 {
340         struct block_device *bdev = NULL;
341         struct super_block *s;
342         struct dentry *root;
343         int error = 0;
344
345         bdev = open_bdev_excl(dev_name, flags, fs_type);
346         if (IS_ERR(bdev))
347                 return PTR_ERR(bdev);
348
349         /*
350          * once the super is inserted into the list by sget, s_umount
351          * will protect the lockfs code from trying to start a snapshot
352          * while we are mounting
353          */
354         down(&bdev->bd_mount_sem);
355         s = sget(fs_type, test_bdev_super, set_bdev_super, bdev);
356         up(&bdev->bd_mount_sem);
357         if (IS_ERR(s))
358                 goto error_s;
359
360         if (s->s_root) {
361                 if ((flags ^ s->s_flags) & MS_RDONLY) {
362                         up_write(&s->s_umount);
363                         deactivate_super(s);
364                         error = -EBUSY;
365                         goto error_bdev;
366                 }
367
368                 close_bdev_excl(bdev);
369         } else {
370                 char b[BDEVNAME_SIZE];
371
372                 s->s_flags = flags;
373                 strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
374                 sb_set_blocksize(s, block_size(bdev));
375                 error = fill_super(s, data, flags & MS_SILENT ? 1 : 0);
376                 if (error) {
377                         up_write(&s->s_umount);
378                         deactivate_super(s);
379                         goto error;
380                 }
381
382                 s->s_flags |= MS_ACTIVE;
383         }
384
385         if (subvol) {
386                 root = lookup_one_len(subvol, s->s_root, strlen(subvol));
387                 if (IS_ERR(root)) {
388                         up_write(&s->s_umount);
389                         deactivate_super(s);
390                         error = PTR_ERR(root);
391                         goto error;
392                 }
393                 if (!root->d_inode) {
394                         dput(root);
395                         up_write(&s->s_umount);
396                         deactivate_super(s);
397                         error = -ENXIO;
398                         goto error;
399                 }
400         } else {
401                 root = dget(s->s_root);
402         }
403
404         mnt->mnt_sb = s;
405         mnt->mnt_root = root;
406         return 0;
407
408 error_s:
409         error = PTR_ERR(s);
410 error_bdev:
411         close_bdev_excl(bdev);
412 error:
413         return error;
414 }
415 /* end copy & paste */
416
417 static int btrfs_get_sb(struct file_system_type *fs_type,
418         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
419 {
420         int ret;
421         char *subvol_name = NULL;
422
423         parse_options((char *)data, NULL, &subvol_name);
424         ret = btrfs_get_sb_bdev(fs_type, flags, dev_name, data,
425                         btrfs_fill_super, mnt,
426                         subvol_name ? subvol_name : "default");
427         if (subvol_name)
428                 kfree(subvol_name);
429         return ret;
430 }
431
432 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
433 {
434         struct btrfs_root *root = btrfs_sb(dentry->d_sb);
435         struct btrfs_super_block *disk_super = &root->fs_info->super_copy;
436         int bits = dentry->d_sb->s_blocksize_bits;
437
438         buf->f_namelen = BTRFS_NAME_LEN;
439         buf->f_blocks = btrfs_super_total_bytes(disk_super) >> bits;
440         buf->f_bfree = buf->f_blocks -
441                 (btrfs_super_bytes_used(disk_super) >> bits);
442         buf->f_bavail = buf->f_bfree;
443         buf->f_bsize = dentry->d_sb->s_blocksize;
444         buf->f_type = BTRFS_SUPER_MAGIC;
445         return 0;
446 }
447
448 static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
449                                 unsigned long arg)
450 {
451         printk("btrfs control ioctl %d\n", cmd);
452         return 0;
453 }
454
455 static struct file_system_type btrfs_fs_type = {
456         .owner          = THIS_MODULE,
457         .name           = "btrfs",
458         .get_sb         = btrfs_get_sb,
459         .kill_sb        = kill_block_super,
460         .fs_flags       = FS_REQUIRES_DEV,
461 };
462
463 static void btrfs_write_super_lockfs(struct super_block *sb)
464 {
465         struct btrfs_root *root = btrfs_sb(sb);
466         btrfs_transaction_flush_work(root);
467 }
468
469 static void btrfs_unlockfs(struct super_block *sb)
470 {
471         struct btrfs_root *root = btrfs_sb(sb);
472         btrfs_transaction_queue_work(root, HZ * 30);
473 }
474
475 static struct super_operations btrfs_super_ops = {
476         .delete_inode   = btrfs_delete_inode,
477         .put_inode      = btrfs_put_inode,
478         .put_super      = btrfs_put_super,
479         .write_super    = btrfs_write_super,
480         .sync_fs        = btrfs_sync_fs,
481 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,25)
482         .read_inode     = btrfs_read_locked_inode,
483 #else
484         .show_options   = generic_show_options,
485 #endif
486         .write_inode    = btrfs_write_inode,
487         .dirty_inode    = btrfs_dirty_inode,
488         .alloc_inode    = btrfs_alloc_inode,
489         .destroy_inode  = btrfs_destroy_inode,
490         .statfs         = btrfs_statfs,
491         .write_super_lockfs = btrfs_write_super_lockfs,
492         .unlockfs       = btrfs_unlockfs,
493 };
494
495 static const struct file_operations btrfs_ctl_fops = {
496         .unlocked_ioctl  = btrfs_control_ioctl,
497         .compat_ioctl = btrfs_control_ioctl,
498         .owner   = THIS_MODULE,
499 };
500
501 static struct miscdevice btrfs_misc = {
502         .minor          = MISC_DYNAMIC_MINOR,
503         .name           = "btrfs-control",
504         .fops           = &btrfs_ctl_fops
505 };
506
507 static int btrfs_interface_init(void)
508 {
509         return misc_register(&btrfs_misc);
510 }
511
512 void btrfs_interface_exit(void)
513 {
514         if (misc_deregister(&btrfs_misc) < 0)
515                 printk("misc_deregister failed for control device");
516 }
517
518 static int __init init_btrfs_fs(void)
519 {
520         int err;
521
522         err = btrfs_init_sysfs();
523         if (err)
524                 return err;
525
526         btrfs_init_transaction_sys();
527         err = btrfs_init_cachep();
528         if (err)
529                 goto free_transaction_sys;
530
531         err = extent_io_init();
532         if (err)
533                 goto free_cachep;
534
535         err = extent_map_init();
536         if (err)
537                 goto free_extent_io;
538
539         err = btrfs_interface_init();
540         if (err)
541                 goto free_extent_map;
542         err = register_filesystem(&btrfs_fs_type);
543         if (err)
544                 goto unregister_ioctl;
545         return 0;
546
547 unregister_ioctl:
548         btrfs_interface_exit();
549 free_extent_map:
550         extent_map_exit();
551 free_extent_io:
552         extent_io_exit();
553 free_cachep:
554         btrfs_destroy_cachep();
555 free_transaction_sys:
556         btrfs_exit_transaction_sys();
557         btrfs_exit_sysfs();
558         return err;
559 }
560
561 static void __exit exit_btrfs_fs(void)
562 {
563         btrfs_exit_transaction_sys();
564         btrfs_destroy_cachep();
565         extent_map_exit();
566         extent_io_exit();
567         btrfs_interface_exit();
568         unregister_filesystem(&btrfs_fs_type);
569         btrfs_exit_sysfs();
570 }
571
572 module_init(init_btrfs_fs)
573 module_exit(exit_btrfs_fs)
574
575 MODULE_LICENSE("GPL");