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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/fs/block_dev.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | * Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE | |
6 | */ | |
7 | ||
8 | #include <linux/config.h> | |
9 | #include <linux/init.h> | |
10 | #include <linux/mm.h> | |
11 | #include <linux/fcntl.h> | |
12 | #include <linux/slab.h> | |
13 | #include <linux/kmod.h> | |
14 | #include <linux/major.h> | |
15 | #include <linux/devfs_fs_kernel.h> | |
16 | #include <linux/smp_lock.h> | |
17 | #include <linux/highmem.h> | |
18 | #include <linux/blkdev.h> | |
19 | #include <linux/module.h> | |
20 | #include <linux/blkpg.h> | |
21 | #include <linux/buffer_head.h> | |
22 | #include <linux/mpage.h> | |
23 | #include <linux/mount.h> | |
24 | #include <linux/uio.h> | |
25 | #include <linux/namei.h> | |
26 | #include <asm/uaccess.h> | |
27 | ||
28 | struct bdev_inode { | |
29 | struct block_device bdev; | |
30 | struct inode vfs_inode; | |
31 | }; | |
32 | ||
33 | static inline struct bdev_inode *BDEV_I(struct inode *inode) | |
34 | { | |
35 | return container_of(inode, struct bdev_inode, vfs_inode); | |
36 | } | |
37 | ||
38 | inline struct block_device *I_BDEV(struct inode *inode) | |
39 | { | |
40 | return &BDEV_I(inode)->bdev; | |
41 | } | |
42 | ||
43 | EXPORT_SYMBOL(I_BDEV); | |
44 | ||
45 | static sector_t max_block(struct block_device *bdev) | |
46 | { | |
47 | sector_t retval = ~((sector_t)0); | |
48 | loff_t sz = i_size_read(bdev->bd_inode); | |
49 | ||
50 | if (sz) { | |
51 | unsigned int size = block_size(bdev); | |
52 | unsigned int sizebits = blksize_bits(size); | |
53 | retval = (sz >> sizebits); | |
54 | } | |
55 | return retval; | |
56 | } | |
57 | ||
58 | /* Kill _all_ buffers, dirty or not.. */ | |
59 | static void kill_bdev(struct block_device *bdev) | |
60 | { | |
61 | invalidate_bdev(bdev, 1); | |
62 | truncate_inode_pages(bdev->bd_inode->i_mapping, 0); | |
63 | } | |
64 | ||
65 | int set_blocksize(struct block_device *bdev, int size) | |
66 | { | |
67 | /* Size must be a power of two, and between 512 and PAGE_SIZE */ | |
68 | if (size > PAGE_SIZE || size < 512 || (size & (size-1))) | |
69 | return -EINVAL; | |
70 | ||
71 | /* Size cannot be smaller than the size supported by the device */ | |
72 | if (size < bdev_hardsect_size(bdev)) | |
73 | return -EINVAL; | |
74 | ||
75 | /* Don't change the size if it is same as current */ | |
76 | if (bdev->bd_block_size != size) { | |
77 | sync_blockdev(bdev); | |
78 | bdev->bd_block_size = size; | |
79 | bdev->bd_inode->i_blkbits = blksize_bits(size); | |
80 | kill_bdev(bdev); | |
81 | } | |
82 | return 0; | |
83 | } | |
84 | ||
85 | EXPORT_SYMBOL(set_blocksize); | |
86 | ||
87 | int sb_set_blocksize(struct super_block *sb, int size) | |
88 | { | |
1da177e4 LT |
89 | if (set_blocksize(sb->s_bdev, size)) |
90 | return 0; | |
91 | /* If we get here, we know size is power of two | |
92 | * and it's value is between 512 and PAGE_SIZE */ | |
93 | sb->s_blocksize = size; | |
38885bd4 | 94 | sb->s_blocksize_bits = blksize_bits(size); |
1da177e4 LT |
95 | return sb->s_blocksize; |
96 | } | |
97 | ||
98 | EXPORT_SYMBOL(sb_set_blocksize); | |
99 | ||
100 | int sb_min_blocksize(struct super_block *sb, int size) | |
101 | { | |
102 | int minsize = bdev_hardsect_size(sb->s_bdev); | |
103 | if (size < minsize) | |
104 | size = minsize; | |
105 | return sb_set_blocksize(sb, size); | |
106 | } | |
107 | ||
108 | EXPORT_SYMBOL(sb_min_blocksize); | |
109 | ||
110 | static int | |
111 | blkdev_get_block(struct inode *inode, sector_t iblock, | |
112 | struct buffer_head *bh, int create) | |
113 | { | |
114 | if (iblock >= max_block(I_BDEV(inode))) { | |
115 | if (create) | |
116 | return -EIO; | |
117 | ||
118 | /* | |
119 | * for reads, we're just trying to fill a partial page. | |
120 | * return a hole, they will have to call get_block again | |
121 | * before they can fill it, and they will get -EIO at that | |
122 | * time | |
123 | */ | |
124 | return 0; | |
125 | } | |
126 | bh->b_bdev = I_BDEV(inode); | |
127 | bh->b_blocknr = iblock; | |
128 | set_buffer_mapped(bh); | |
129 | return 0; | |
130 | } | |
131 | ||
132 | static int | |
133 | blkdev_get_blocks(struct inode *inode, sector_t iblock, | |
1d8fa7a2 | 134 | struct buffer_head *bh, int create) |
1da177e4 LT |
135 | { |
136 | sector_t end_block = max_block(I_BDEV(inode)); | |
1d8fa7a2 | 137 | unsigned long max_blocks = bh->b_size >> inode->i_blkbits; |
1da177e4 LT |
138 | |
139 | if ((iblock + max_blocks) > end_block) { | |
140 | max_blocks = end_block - iblock; | |
141 | if ((long)max_blocks <= 0) { | |
142 | if (create) | |
143 | return -EIO; /* write fully beyond EOF */ | |
144 | /* | |
145 | * It is a read which is fully beyond EOF. We return | |
146 | * a !buffer_mapped buffer | |
147 | */ | |
148 | max_blocks = 0; | |
149 | } | |
150 | } | |
151 | ||
152 | bh->b_bdev = I_BDEV(inode); | |
153 | bh->b_blocknr = iblock; | |
154 | bh->b_size = max_blocks << inode->i_blkbits; | |
155 | if (max_blocks) | |
156 | set_buffer_mapped(bh); | |
157 | return 0; | |
158 | } | |
159 | ||
160 | static ssize_t | |
161 | blkdev_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov, | |
162 | loff_t offset, unsigned long nr_segs) | |
163 | { | |
164 | struct file *file = iocb->ki_filp; | |
165 | struct inode *inode = file->f_mapping->host; | |
166 | ||
167 | return blockdev_direct_IO_no_locking(rw, iocb, inode, I_BDEV(inode), | |
168 | iov, offset, nr_segs, blkdev_get_blocks, NULL); | |
169 | } | |
170 | ||
171 | static int blkdev_writepage(struct page *page, struct writeback_control *wbc) | |
172 | { | |
173 | return block_write_full_page(page, blkdev_get_block, wbc); | |
174 | } | |
175 | ||
176 | static int blkdev_readpage(struct file * file, struct page * page) | |
177 | { | |
178 | return block_read_full_page(page, blkdev_get_block); | |
179 | } | |
180 | ||
181 | static int blkdev_prepare_write(struct file *file, struct page *page, unsigned from, unsigned to) | |
182 | { | |
183 | return block_prepare_write(page, from, to, blkdev_get_block); | |
184 | } | |
185 | ||
186 | static int blkdev_commit_write(struct file *file, struct page *page, unsigned from, unsigned to) | |
187 | { | |
188 | return block_commit_write(page, from, to); | |
189 | } | |
190 | ||
191 | /* | |
192 | * private llseek: | |
193 | * for a block special file file->f_dentry->d_inode->i_size is zero | |
194 | * so we compute the size by hand (just as in block_read/write above) | |
195 | */ | |
196 | static loff_t block_llseek(struct file *file, loff_t offset, int origin) | |
197 | { | |
198 | struct inode *bd_inode = file->f_mapping->host; | |
199 | loff_t size; | |
200 | loff_t retval; | |
201 | ||
1b1dcc1b | 202 | mutex_lock(&bd_inode->i_mutex); |
1da177e4 LT |
203 | size = i_size_read(bd_inode); |
204 | ||
205 | switch (origin) { | |
206 | case 2: | |
207 | offset += size; | |
208 | break; | |
209 | case 1: | |
210 | offset += file->f_pos; | |
211 | } | |
212 | retval = -EINVAL; | |
213 | if (offset >= 0 && offset <= size) { | |
214 | if (offset != file->f_pos) { | |
215 | file->f_pos = offset; | |
216 | } | |
217 | retval = offset; | |
218 | } | |
1b1dcc1b | 219 | mutex_unlock(&bd_inode->i_mutex); |
1da177e4 LT |
220 | return retval; |
221 | } | |
222 | ||
223 | /* | |
224 | * Filp is never NULL; the only case when ->fsync() is called with | |
225 | * NULL first argument is nfsd_sync_dir() and that's not a directory. | |
226 | */ | |
227 | ||
228 | static int block_fsync(struct file *filp, struct dentry *dentry, int datasync) | |
229 | { | |
230 | return sync_blockdev(I_BDEV(filp->f_mapping->host)); | |
231 | } | |
232 | ||
233 | /* | |
234 | * pseudo-fs | |
235 | */ | |
236 | ||
237 | static __cacheline_aligned_in_smp DEFINE_SPINLOCK(bdev_lock); | |
fa3536cc | 238 | static kmem_cache_t * bdev_cachep __read_mostly; |
1da177e4 LT |
239 | |
240 | static struct inode *bdev_alloc_inode(struct super_block *sb) | |
241 | { | |
242 | struct bdev_inode *ei = kmem_cache_alloc(bdev_cachep, SLAB_KERNEL); | |
243 | if (!ei) | |
244 | return NULL; | |
245 | return &ei->vfs_inode; | |
246 | } | |
247 | ||
248 | static void bdev_destroy_inode(struct inode *inode) | |
249 | { | |
250 | struct bdev_inode *bdi = BDEV_I(inode); | |
251 | ||
252 | bdi->bdev.bd_inode_backing_dev_info = NULL; | |
253 | kmem_cache_free(bdev_cachep, bdi); | |
254 | } | |
255 | ||
256 | static void init_once(void * foo, kmem_cache_t * cachep, unsigned long flags) | |
257 | { | |
258 | struct bdev_inode *ei = (struct bdev_inode *) foo; | |
259 | struct block_device *bdev = &ei->bdev; | |
260 | ||
261 | if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) == | |
262 | SLAB_CTOR_CONSTRUCTOR) | |
263 | { | |
264 | memset(bdev, 0, sizeof(*bdev)); | |
c039e313 AV |
265 | mutex_init(&bdev->bd_mutex); |
266 | mutex_init(&bdev->bd_mount_mutex); | |
1da177e4 LT |
267 | INIT_LIST_HEAD(&bdev->bd_inodes); |
268 | INIT_LIST_HEAD(&bdev->bd_list); | |
641dc636 JN |
269 | #ifdef CONFIG_SYSFS |
270 | INIT_LIST_HEAD(&bdev->bd_holder_list); | |
271 | #endif | |
1da177e4 LT |
272 | inode_init_once(&ei->vfs_inode); |
273 | } | |
274 | } | |
275 | ||
276 | static inline void __bd_forget(struct inode *inode) | |
277 | { | |
278 | list_del_init(&inode->i_devices); | |
279 | inode->i_bdev = NULL; | |
280 | inode->i_mapping = &inode->i_data; | |
281 | } | |
282 | ||
283 | static void bdev_clear_inode(struct inode *inode) | |
284 | { | |
285 | struct block_device *bdev = &BDEV_I(inode)->bdev; | |
286 | struct list_head *p; | |
287 | spin_lock(&bdev_lock); | |
288 | while ( (p = bdev->bd_inodes.next) != &bdev->bd_inodes ) { | |
289 | __bd_forget(list_entry(p, struct inode, i_devices)); | |
290 | } | |
291 | list_del_init(&bdev->bd_list); | |
292 | spin_unlock(&bdev_lock); | |
293 | } | |
294 | ||
295 | static struct super_operations bdev_sops = { | |
296 | .statfs = simple_statfs, | |
297 | .alloc_inode = bdev_alloc_inode, | |
298 | .destroy_inode = bdev_destroy_inode, | |
299 | .drop_inode = generic_delete_inode, | |
300 | .clear_inode = bdev_clear_inode, | |
301 | }; | |
302 | ||
303 | static struct super_block *bd_get_sb(struct file_system_type *fs_type, | |
304 | int flags, const char *dev_name, void *data) | |
305 | { | |
306 | return get_sb_pseudo(fs_type, "bdev:", &bdev_sops, 0x62646576); | |
307 | } | |
308 | ||
309 | static struct file_system_type bd_type = { | |
310 | .name = "bdev", | |
311 | .get_sb = bd_get_sb, | |
312 | .kill_sb = kill_anon_super, | |
313 | }; | |
314 | ||
fa3536cc | 315 | static struct vfsmount *bd_mnt __read_mostly; |
1da177e4 LT |
316 | struct super_block *blockdev_superblock; |
317 | ||
318 | void __init bdev_cache_init(void) | |
319 | { | |
320 | int err; | |
321 | bdev_cachep = kmem_cache_create("bdev_cache", sizeof(struct bdev_inode), | |
fffb60f9 PJ |
322 | 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT| |
323 | SLAB_MEM_SPREAD|SLAB_PANIC), | |
1da177e4 LT |
324 | init_once, NULL); |
325 | err = register_filesystem(&bd_type); | |
326 | if (err) | |
327 | panic("Cannot register bdev pseudo-fs"); | |
328 | bd_mnt = kern_mount(&bd_type); | |
329 | err = PTR_ERR(bd_mnt); | |
330 | if (IS_ERR(bd_mnt)) | |
331 | panic("Cannot create bdev pseudo-fs"); | |
332 | blockdev_superblock = bd_mnt->mnt_sb; /* For writeback */ | |
333 | } | |
334 | ||
335 | /* | |
336 | * Most likely _very_ bad one - but then it's hardly critical for small | |
337 | * /dev and can be fixed when somebody will need really large one. | |
338 | * Keep in mind that it will be fed through icache hash function too. | |
339 | */ | |
340 | static inline unsigned long hash(dev_t dev) | |
341 | { | |
342 | return MAJOR(dev)+MINOR(dev); | |
343 | } | |
344 | ||
345 | static int bdev_test(struct inode *inode, void *data) | |
346 | { | |
347 | return BDEV_I(inode)->bdev.bd_dev == *(dev_t *)data; | |
348 | } | |
349 | ||
350 | static int bdev_set(struct inode *inode, void *data) | |
351 | { | |
352 | BDEV_I(inode)->bdev.bd_dev = *(dev_t *)data; | |
353 | return 0; | |
354 | } | |
355 | ||
356 | static LIST_HEAD(all_bdevs); | |
357 | ||
358 | struct block_device *bdget(dev_t dev) | |
359 | { | |
360 | struct block_device *bdev; | |
361 | struct inode *inode; | |
362 | ||
363 | inode = iget5_locked(bd_mnt->mnt_sb, hash(dev), | |
364 | bdev_test, bdev_set, &dev); | |
365 | ||
366 | if (!inode) | |
367 | return NULL; | |
368 | ||
369 | bdev = &BDEV_I(inode)->bdev; | |
370 | ||
371 | if (inode->i_state & I_NEW) { | |
372 | bdev->bd_contains = NULL; | |
373 | bdev->bd_inode = inode; | |
374 | bdev->bd_block_size = (1 << inode->i_blkbits); | |
375 | bdev->bd_part_count = 0; | |
376 | bdev->bd_invalidated = 0; | |
377 | inode->i_mode = S_IFBLK; | |
378 | inode->i_rdev = dev; | |
379 | inode->i_bdev = bdev; | |
380 | inode->i_data.a_ops = &def_blk_aops; | |
381 | mapping_set_gfp_mask(&inode->i_data, GFP_USER); | |
382 | inode->i_data.backing_dev_info = &default_backing_dev_info; | |
383 | spin_lock(&bdev_lock); | |
384 | list_add(&bdev->bd_list, &all_bdevs); | |
385 | spin_unlock(&bdev_lock); | |
386 | unlock_new_inode(inode); | |
387 | } | |
388 | return bdev; | |
389 | } | |
390 | ||
391 | EXPORT_SYMBOL(bdget); | |
392 | ||
393 | long nr_blockdev_pages(void) | |
394 | { | |
395 | struct list_head *p; | |
396 | long ret = 0; | |
397 | spin_lock(&bdev_lock); | |
398 | list_for_each(p, &all_bdevs) { | |
399 | struct block_device *bdev; | |
400 | bdev = list_entry(p, struct block_device, bd_list); | |
401 | ret += bdev->bd_inode->i_mapping->nrpages; | |
402 | } | |
403 | spin_unlock(&bdev_lock); | |
404 | return ret; | |
405 | } | |
406 | ||
407 | void bdput(struct block_device *bdev) | |
408 | { | |
409 | iput(bdev->bd_inode); | |
410 | } | |
411 | ||
412 | EXPORT_SYMBOL(bdput); | |
413 | ||
414 | static struct block_device *bd_acquire(struct inode *inode) | |
415 | { | |
416 | struct block_device *bdev; | |
417 | spin_lock(&bdev_lock); | |
418 | bdev = inode->i_bdev; | |
419 | if (bdev && igrab(bdev->bd_inode)) { | |
420 | spin_unlock(&bdev_lock); | |
421 | return bdev; | |
422 | } | |
423 | spin_unlock(&bdev_lock); | |
424 | bdev = bdget(inode->i_rdev); | |
425 | if (bdev) { | |
426 | spin_lock(&bdev_lock); | |
427 | if (inode->i_bdev) | |
428 | __bd_forget(inode); | |
429 | inode->i_bdev = bdev; | |
430 | inode->i_mapping = bdev->bd_inode->i_mapping; | |
431 | list_add(&inode->i_devices, &bdev->bd_inodes); | |
432 | spin_unlock(&bdev_lock); | |
433 | } | |
434 | return bdev; | |
435 | } | |
436 | ||
437 | /* Call when you free inode */ | |
438 | ||
439 | void bd_forget(struct inode *inode) | |
440 | { | |
441 | spin_lock(&bdev_lock); | |
442 | if (inode->i_bdev) | |
443 | __bd_forget(inode); | |
444 | spin_unlock(&bdev_lock); | |
445 | } | |
446 | ||
447 | int bd_claim(struct block_device *bdev, void *holder) | |
448 | { | |
449 | int res; | |
450 | spin_lock(&bdev_lock); | |
451 | ||
452 | /* first decide result */ | |
453 | if (bdev->bd_holder == holder) | |
454 | res = 0; /* already a holder */ | |
455 | else if (bdev->bd_holder != NULL) | |
456 | res = -EBUSY; /* held by someone else */ | |
457 | else if (bdev->bd_contains == bdev) | |
458 | res = 0; /* is a whole device which isn't held */ | |
459 | ||
460 | else if (bdev->bd_contains->bd_holder == bd_claim) | |
461 | res = 0; /* is a partition of a device that is being partitioned */ | |
462 | else if (bdev->bd_contains->bd_holder != NULL) | |
463 | res = -EBUSY; /* is a partition of a held device */ | |
464 | else | |
465 | res = 0; /* is a partition of an un-held device */ | |
466 | ||
467 | /* now impose change */ | |
468 | if (res==0) { | |
469 | /* note that for a whole device bd_holders | |
470 | * will be incremented twice, and bd_holder will | |
471 | * be set to bd_claim before being set to holder | |
472 | */ | |
473 | bdev->bd_contains->bd_holders ++; | |
474 | bdev->bd_contains->bd_holder = bd_claim; | |
475 | bdev->bd_holders++; | |
476 | bdev->bd_holder = holder; | |
477 | } | |
478 | spin_unlock(&bdev_lock); | |
479 | return res; | |
480 | } | |
481 | ||
482 | EXPORT_SYMBOL(bd_claim); | |
483 | ||
484 | void bd_release(struct block_device *bdev) | |
485 | { | |
486 | spin_lock(&bdev_lock); | |
487 | if (!--bdev->bd_contains->bd_holders) | |
488 | bdev->bd_contains->bd_holder = NULL; | |
489 | if (!--bdev->bd_holders) | |
490 | bdev->bd_holder = NULL; | |
491 | spin_unlock(&bdev_lock); | |
492 | } | |
493 | ||
494 | EXPORT_SYMBOL(bd_release); | |
495 | ||
641dc636 JN |
496 | #ifdef CONFIG_SYSFS |
497 | /* | |
498 | * Functions for bd_claim_by_kobject / bd_release_from_kobject | |
499 | * | |
500 | * If a kobject is passed to bd_claim_by_kobject() | |
501 | * and the kobject has a parent directory, | |
502 | * following symlinks are created: | |
503 | * o from the kobject to the claimed bdev | |
504 | * o from "holders" directory of the bdev to the parent of the kobject | |
505 | * bd_release_from_kobject() removes these symlinks. | |
506 | * | |
507 | * Example: | |
508 | * If /dev/dm-0 maps to /dev/sda, kobject corresponding to | |
509 | * /sys/block/dm-0/slaves is passed to bd_claim_by_kobject(), then: | |
510 | * /sys/block/dm-0/slaves/sda --> /sys/block/sda | |
511 | * /sys/block/sda/holders/dm-0 --> /sys/block/dm-0 | |
512 | */ | |
513 | ||
514 | static struct kobject *bdev_get_kobj(struct block_device *bdev) | |
515 | { | |
516 | if (bdev->bd_contains != bdev) | |
517 | return kobject_get(&bdev->bd_part->kobj); | |
518 | else | |
519 | return kobject_get(&bdev->bd_disk->kobj); | |
520 | } | |
521 | ||
522 | static struct kobject *bdev_get_holder(struct block_device *bdev) | |
523 | { | |
524 | if (bdev->bd_contains != bdev) | |
525 | return kobject_get(bdev->bd_part->holder_dir); | |
526 | else | |
527 | return kobject_get(bdev->bd_disk->holder_dir); | |
528 | } | |
529 | ||
530 | static void add_symlink(struct kobject *from, struct kobject *to) | |
531 | { | |
532 | if (!from || !to) | |
533 | return; | |
534 | sysfs_create_link(from, to, kobject_name(to)); | |
535 | } | |
536 | ||
537 | static void del_symlink(struct kobject *from, struct kobject *to) | |
538 | { | |
539 | if (!from || !to) | |
540 | return; | |
541 | sysfs_remove_link(from, kobject_name(to)); | |
542 | } | |
543 | ||
544 | /* | |
545 | * 'struct bd_holder' contains pointers to kobjects symlinked by | |
546 | * bd_claim_by_kobject. | |
547 | * It's connected to bd_holder_list which is protected by bdev->bd_sem. | |
548 | */ | |
549 | struct bd_holder { | |
550 | struct list_head list; /* chain of holders of the bdev */ | |
551 | int count; /* references from the holder */ | |
552 | struct kobject *sdir; /* holder object, e.g. "/block/dm-0/slaves" */ | |
553 | struct kobject *hdev; /* e.g. "/block/dm-0" */ | |
554 | struct kobject *hdir; /* e.g. "/block/sda/holders" */ | |
555 | struct kobject *sdev; /* e.g. "/block/sda" */ | |
556 | }; | |
557 | ||
558 | /* | |
559 | * Get references of related kobjects at once. | |
560 | * Returns 1 on success. 0 on failure. | |
561 | * | |
562 | * Should call bd_holder_release_dirs() after successful use. | |
563 | */ | |
564 | static int bd_holder_grab_dirs(struct block_device *bdev, | |
565 | struct bd_holder *bo) | |
566 | { | |
567 | if (!bdev || !bo) | |
568 | return 0; | |
569 | ||
570 | bo->sdir = kobject_get(bo->sdir); | |
571 | if (!bo->sdir) | |
572 | return 0; | |
573 | ||
574 | bo->hdev = kobject_get(bo->sdir->parent); | |
575 | if (!bo->hdev) | |
576 | goto fail_put_sdir; | |
577 | ||
578 | bo->sdev = bdev_get_kobj(bdev); | |
579 | if (!bo->sdev) | |
580 | goto fail_put_hdev; | |
581 | ||
582 | bo->hdir = bdev_get_holder(bdev); | |
583 | if (!bo->hdir) | |
584 | goto fail_put_sdev; | |
585 | ||
586 | return 1; | |
587 | ||
588 | fail_put_sdev: | |
589 | kobject_put(bo->sdev); | |
590 | fail_put_hdev: | |
591 | kobject_put(bo->hdev); | |
592 | fail_put_sdir: | |
593 | kobject_put(bo->sdir); | |
594 | ||
595 | return 0; | |
596 | } | |
597 | ||
598 | /* Put references of related kobjects at once. */ | |
599 | static void bd_holder_release_dirs(struct bd_holder *bo) | |
600 | { | |
601 | kobject_put(bo->hdir); | |
602 | kobject_put(bo->sdev); | |
603 | kobject_put(bo->hdev); | |
604 | kobject_put(bo->sdir); | |
605 | } | |
606 | ||
607 | static struct bd_holder *alloc_bd_holder(struct kobject *kobj) | |
608 | { | |
609 | struct bd_holder *bo; | |
610 | ||
611 | bo = kzalloc(sizeof(*bo), GFP_KERNEL); | |
612 | if (!bo) | |
613 | return NULL; | |
614 | ||
615 | bo->count = 1; | |
616 | bo->sdir = kobj; | |
617 | ||
618 | return bo; | |
619 | } | |
620 | ||
621 | static void free_bd_holder(struct bd_holder *bo) | |
622 | { | |
623 | kfree(bo); | |
624 | } | |
625 | ||
626 | /** | |
627 | * add_bd_holder - create sysfs symlinks for bd_claim() relationship | |
628 | * | |
629 | * @bdev: block device to be bd_claimed | |
630 | * @bo: preallocated and initialized by alloc_bd_holder() | |
631 | * | |
632 | * If there is no matching entry with @bo in @bdev->bd_holder_list, | |
633 | * add @bo to the list, create symlinks. | |
634 | * | |
635 | * Returns 1 if @bo was added to the list. | |
636 | * Returns 0 if @bo wasn't used by any reason and should be freed. | |
637 | */ | |
638 | static int add_bd_holder(struct block_device *bdev, struct bd_holder *bo) | |
639 | { | |
640 | struct bd_holder *tmp; | |
641 | ||
642 | if (!bo) | |
643 | return 0; | |
644 | ||
645 | list_for_each_entry(tmp, &bdev->bd_holder_list, list) { | |
646 | if (tmp->sdir == bo->sdir) { | |
647 | tmp->count++; | |
648 | return 0; | |
649 | } | |
650 | } | |
651 | ||
652 | if (!bd_holder_grab_dirs(bdev, bo)) | |
653 | return 0; | |
654 | ||
655 | add_symlink(bo->sdir, bo->sdev); | |
656 | add_symlink(bo->hdir, bo->hdev); | |
657 | list_add_tail(&bo->list, &bdev->bd_holder_list); | |
658 | return 1; | |
659 | } | |
660 | ||
661 | /** | |
662 | * del_bd_holder - delete sysfs symlinks for bd_claim() relationship | |
663 | * | |
664 | * @bdev: block device to be bd_claimed | |
665 | * @kobj: holder's kobject | |
666 | * | |
667 | * If there is matching entry with @kobj in @bdev->bd_holder_list | |
668 | * and no other bd_claim() from the same kobject, | |
669 | * remove the struct bd_holder from the list, delete symlinks for it. | |
670 | * | |
671 | * Returns a pointer to the struct bd_holder when it's removed from the list | |
672 | * and ready to be freed. | |
673 | * Returns NULL if matching claim isn't found or there is other bd_claim() | |
674 | * by the same kobject. | |
675 | */ | |
676 | static struct bd_holder *del_bd_holder(struct block_device *bdev, | |
677 | struct kobject *kobj) | |
678 | { | |
679 | struct bd_holder *bo; | |
680 | ||
681 | list_for_each_entry(bo, &bdev->bd_holder_list, list) { | |
682 | if (bo->sdir == kobj) { | |
683 | bo->count--; | |
684 | BUG_ON(bo->count < 0); | |
685 | if (!bo->count) { | |
686 | list_del(&bo->list); | |
687 | del_symlink(bo->sdir, bo->sdev); | |
688 | del_symlink(bo->hdir, bo->hdev); | |
689 | bd_holder_release_dirs(bo); | |
690 | return bo; | |
691 | } | |
692 | break; | |
693 | } | |
694 | } | |
695 | ||
696 | return NULL; | |
697 | } | |
698 | ||
699 | /** | |
700 | * bd_claim_by_kobject - bd_claim() with additional kobject signature | |
701 | * | |
702 | * @bdev: block device to be claimed | |
703 | * @holder: holder's signature | |
704 | * @kobj: holder's kobject | |
705 | * | |
706 | * Do bd_claim() and if it succeeds, create sysfs symlinks between | |
707 | * the bdev and the holder's kobject. | |
708 | * Use bd_release_from_kobject() when relesing the claimed bdev. | |
709 | * | |
710 | * Returns 0 on success. (same as bd_claim()) | |
711 | * Returns errno on failure. | |
712 | */ | |
713 | static int bd_claim_by_kobject(struct block_device *bdev, void *holder, | |
714 | struct kobject *kobj) | |
715 | { | |
716 | int res; | |
717 | struct bd_holder *bo; | |
718 | ||
719 | if (!kobj) | |
720 | return -EINVAL; | |
721 | ||
722 | bo = alloc_bd_holder(kobj); | |
723 | if (!bo) | |
724 | return -ENOMEM; | |
725 | ||
b4cf1b72 | 726 | mutex_lock(&bdev->bd_mutex); |
641dc636 JN |
727 | res = bd_claim(bdev, holder); |
728 | if (res || !add_bd_holder(bdev, bo)) | |
729 | free_bd_holder(bo); | |
b4cf1b72 | 730 | mutex_unlock(&bdev->bd_mutex); |
641dc636 JN |
731 | |
732 | return res; | |
733 | } | |
734 | ||
735 | /** | |
736 | * bd_release_from_kobject - bd_release() with additional kobject signature | |
737 | * | |
738 | * @bdev: block device to be released | |
739 | * @kobj: holder's kobject | |
740 | * | |
741 | * Do bd_release() and remove sysfs symlinks created by bd_claim_by_kobject(). | |
742 | */ | |
743 | static void bd_release_from_kobject(struct block_device *bdev, | |
744 | struct kobject *kobj) | |
745 | { | |
746 | struct bd_holder *bo; | |
747 | ||
748 | if (!kobj) | |
749 | return; | |
750 | ||
b4cf1b72 | 751 | mutex_lock(&bdev->bd_mutex); |
641dc636 JN |
752 | bd_release(bdev); |
753 | if ((bo = del_bd_holder(bdev, kobj))) | |
754 | free_bd_holder(bo); | |
b4cf1b72 | 755 | mutex_unlock(&bdev->bd_mutex); |
641dc636 JN |
756 | } |
757 | ||
758 | /** | |
759 | * bd_claim_by_disk - wrapper function for bd_claim_by_kobject() | |
760 | * | |
761 | * @bdev: block device to be claimed | |
762 | * @holder: holder's signature | |
763 | * @disk: holder's gendisk | |
764 | * | |
765 | * Call bd_claim_by_kobject() with getting @disk->slave_dir. | |
766 | */ | |
767 | int bd_claim_by_disk(struct block_device *bdev, void *holder, | |
768 | struct gendisk *disk) | |
769 | { | |
770 | return bd_claim_by_kobject(bdev, holder, kobject_get(disk->slave_dir)); | |
771 | } | |
772 | EXPORT_SYMBOL_GPL(bd_claim_by_disk); | |
773 | ||
774 | /** | |
775 | * bd_release_from_disk - wrapper function for bd_release_from_kobject() | |
776 | * | |
777 | * @bdev: block device to be claimed | |
778 | * @disk: holder's gendisk | |
779 | * | |
780 | * Call bd_release_from_kobject() and put @disk->slave_dir. | |
781 | */ | |
782 | void bd_release_from_disk(struct block_device *bdev, struct gendisk *disk) | |
783 | { | |
784 | bd_release_from_kobject(bdev, disk->slave_dir); | |
785 | kobject_put(disk->slave_dir); | |
786 | } | |
787 | EXPORT_SYMBOL_GPL(bd_release_from_disk); | |
788 | #endif | |
789 | ||
1da177e4 LT |
790 | /* |
791 | * Tries to open block device by device number. Use it ONLY if you | |
792 | * really do not have anything better - i.e. when you are behind a | |
793 | * truly sucky interface and all you are given is a device number. _Never_ | |
794 | * to be used for internal purposes. If you ever need it - reconsider | |
795 | * your API. | |
796 | */ | |
797 | struct block_device *open_by_devnum(dev_t dev, unsigned mode) | |
798 | { | |
799 | struct block_device *bdev = bdget(dev); | |
800 | int err = -ENOMEM; | |
801 | int flags = mode & FMODE_WRITE ? O_RDWR : O_RDONLY; | |
802 | if (bdev) | |
803 | err = blkdev_get(bdev, mode, flags); | |
804 | return err ? ERR_PTR(err) : bdev; | |
805 | } | |
806 | ||
807 | EXPORT_SYMBOL(open_by_devnum); | |
808 | ||
809 | /* | |
810 | * This routine checks whether a removable media has been changed, | |
811 | * and invalidates all buffer-cache-entries in that case. This | |
812 | * is a relatively slow routine, so we have to try to minimize using | |
813 | * it. Thus it is called only upon a 'mount' or 'open'. This | |
814 | * is the best way of combining speed and utility, I think. | |
815 | * People changing diskettes in the middle of an operation deserve | |
816 | * to lose :-) | |
817 | */ | |
818 | int check_disk_change(struct block_device *bdev) | |
819 | { | |
820 | struct gendisk *disk = bdev->bd_disk; | |
821 | struct block_device_operations * bdops = disk->fops; | |
822 | ||
823 | if (!bdops->media_changed) | |
824 | return 0; | |
825 | if (!bdops->media_changed(bdev->bd_disk)) | |
826 | return 0; | |
827 | ||
2ef41634 | 828 | if (__invalidate_device(bdev)) |
1da177e4 LT |
829 | printk("VFS: busy inodes on changed media.\n"); |
830 | ||
831 | if (bdops->revalidate_disk) | |
832 | bdops->revalidate_disk(bdev->bd_disk); | |
833 | if (bdev->bd_disk->minors > 1) | |
834 | bdev->bd_invalidated = 1; | |
835 | return 1; | |
836 | } | |
837 | ||
838 | EXPORT_SYMBOL(check_disk_change); | |
839 | ||
840 | void bd_set_size(struct block_device *bdev, loff_t size) | |
841 | { | |
842 | unsigned bsize = bdev_hardsect_size(bdev); | |
843 | ||
844 | bdev->bd_inode->i_size = size; | |
845 | while (bsize < PAGE_CACHE_SIZE) { | |
846 | if (size & bsize) | |
847 | break; | |
848 | bsize <<= 1; | |
849 | } | |
850 | bdev->bd_block_size = bsize; | |
851 | bdev->bd_inode->i_blkbits = blksize_bits(bsize); | |
852 | } | |
853 | EXPORT_SYMBOL(bd_set_size); | |
854 | ||
855 | static int do_open(struct block_device *bdev, struct file *file) | |
856 | { | |
857 | struct module *owner = NULL; | |
858 | struct gendisk *disk; | |
859 | int ret = -ENXIO; | |
860 | int part; | |
861 | ||
862 | file->f_mapping = bdev->bd_inode->i_mapping; | |
863 | lock_kernel(); | |
864 | disk = get_gendisk(bdev->bd_dev, &part); | |
865 | if (!disk) { | |
866 | unlock_kernel(); | |
867 | bdput(bdev); | |
868 | return ret; | |
869 | } | |
870 | owner = disk->fops->owner; | |
871 | ||
c039e313 | 872 | mutex_lock(&bdev->bd_mutex); |
1da177e4 LT |
873 | if (!bdev->bd_openers) { |
874 | bdev->bd_disk = disk; | |
875 | bdev->bd_contains = bdev; | |
876 | if (!part) { | |
877 | struct backing_dev_info *bdi; | |
878 | if (disk->fops->open) { | |
879 | ret = disk->fops->open(bdev->bd_inode, file); | |
880 | if (ret) | |
881 | goto out_first; | |
882 | } | |
883 | if (!bdev->bd_openers) { | |
884 | bd_set_size(bdev,(loff_t)get_capacity(disk)<<9); | |
885 | bdi = blk_get_backing_dev_info(bdev); | |
886 | if (bdi == NULL) | |
887 | bdi = &default_backing_dev_info; | |
888 | bdev->bd_inode->i_data.backing_dev_info = bdi; | |
889 | } | |
890 | if (bdev->bd_invalidated) | |
891 | rescan_partitions(disk, bdev); | |
892 | } else { | |
893 | struct hd_struct *p; | |
894 | struct block_device *whole; | |
895 | whole = bdget_disk(disk, 0); | |
896 | ret = -ENOMEM; | |
897 | if (!whole) | |
898 | goto out_first; | |
899 | ret = blkdev_get(whole, file->f_mode, file->f_flags); | |
900 | if (ret) | |
901 | goto out_first; | |
902 | bdev->bd_contains = whole; | |
c039e313 | 903 | mutex_lock(&whole->bd_mutex); |
1da177e4 LT |
904 | whole->bd_part_count++; |
905 | p = disk->part[part - 1]; | |
906 | bdev->bd_inode->i_data.backing_dev_info = | |
907 | whole->bd_inode->i_data.backing_dev_info; | |
908 | if (!(disk->flags & GENHD_FL_UP) || !p || !p->nr_sects) { | |
909 | whole->bd_part_count--; | |
c039e313 | 910 | mutex_unlock(&whole->bd_mutex); |
1da177e4 LT |
911 | ret = -ENXIO; |
912 | goto out_first; | |
913 | } | |
914 | kobject_get(&p->kobj); | |
915 | bdev->bd_part = p; | |
916 | bd_set_size(bdev, (loff_t) p->nr_sects << 9); | |
c039e313 | 917 | mutex_unlock(&whole->bd_mutex); |
1da177e4 LT |
918 | } |
919 | } else { | |
920 | put_disk(disk); | |
921 | module_put(owner); | |
922 | if (bdev->bd_contains == bdev) { | |
923 | if (bdev->bd_disk->fops->open) { | |
924 | ret = bdev->bd_disk->fops->open(bdev->bd_inode, file); | |
925 | if (ret) | |
926 | goto out; | |
927 | } | |
928 | if (bdev->bd_invalidated) | |
929 | rescan_partitions(bdev->bd_disk, bdev); | |
930 | } else { | |
c039e313 | 931 | mutex_lock(&bdev->bd_contains->bd_mutex); |
1da177e4 | 932 | bdev->bd_contains->bd_part_count++; |
c039e313 | 933 | mutex_unlock(&bdev->bd_contains->bd_mutex); |
1da177e4 LT |
934 | } |
935 | } | |
936 | bdev->bd_openers++; | |
c039e313 | 937 | mutex_unlock(&bdev->bd_mutex); |
1da177e4 LT |
938 | unlock_kernel(); |
939 | return 0; | |
940 | ||
941 | out_first: | |
942 | bdev->bd_disk = NULL; | |
943 | bdev->bd_inode->i_data.backing_dev_info = &default_backing_dev_info; | |
944 | if (bdev != bdev->bd_contains) | |
945 | blkdev_put(bdev->bd_contains); | |
946 | bdev->bd_contains = NULL; | |
947 | put_disk(disk); | |
948 | module_put(owner); | |
949 | out: | |
c039e313 | 950 | mutex_unlock(&bdev->bd_mutex); |
1da177e4 LT |
951 | unlock_kernel(); |
952 | if (ret) | |
953 | bdput(bdev); | |
954 | return ret; | |
955 | } | |
956 | ||
957 | int blkdev_get(struct block_device *bdev, mode_t mode, unsigned flags) | |
958 | { | |
959 | /* | |
960 | * This crockload is due to bad choice of ->open() type. | |
961 | * It will go away. | |
962 | * For now, block device ->open() routine must _not_ | |
963 | * examine anything in 'inode' argument except ->i_rdev. | |
964 | */ | |
965 | struct file fake_file = {}; | |
966 | struct dentry fake_dentry = {}; | |
967 | fake_file.f_mode = mode; | |
968 | fake_file.f_flags = flags; | |
969 | fake_file.f_dentry = &fake_dentry; | |
970 | fake_dentry.d_inode = bdev->bd_inode; | |
971 | ||
972 | return do_open(bdev, &fake_file); | |
973 | } | |
974 | ||
975 | EXPORT_SYMBOL(blkdev_get); | |
976 | ||
977 | static int blkdev_open(struct inode * inode, struct file * filp) | |
978 | { | |
979 | struct block_device *bdev; | |
980 | int res; | |
981 | ||
982 | /* | |
983 | * Preserve backwards compatibility and allow large file access | |
984 | * even if userspace doesn't ask for it explicitly. Some mkfs | |
985 | * binary needs it. We might want to drop this workaround | |
986 | * during an unstable branch. | |
987 | */ | |
988 | filp->f_flags |= O_LARGEFILE; | |
989 | ||
990 | bdev = bd_acquire(inode); | |
991 | ||
992 | res = do_open(bdev, filp); | |
993 | if (res) | |
994 | return res; | |
995 | ||
996 | if (!(filp->f_flags & O_EXCL) ) | |
997 | return 0; | |
998 | ||
999 | if (!(res = bd_claim(bdev, filp))) | |
1000 | return 0; | |
1001 | ||
1002 | blkdev_put(bdev); | |
1003 | return res; | |
1004 | } | |
1005 | ||
1006 | int blkdev_put(struct block_device *bdev) | |
1007 | { | |
1008 | int ret = 0; | |
1009 | struct inode *bd_inode = bdev->bd_inode; | |
1010 | struct gendisk *disk = bdev->bd_disk; | |
1011 | ||
c039e313 | 1012 | mutex_lock(&bdev->bd_mutex); |
1da177e4 LT |
1013 | lock_kernel(); |
1014 | if (!--bdev->bd_openers) { | |
1015 | sync_blockdev(bdev); | |
1016 | kill_bdev(bdev); | |
1017 | } | |
1018 | if (bdev->bd_contains == bdev) { | |
1019 | if (disk->fops->release) | |
1020 | ret = disk->fops->release(bd_inode, NULL); | |
1021 | } else { | |
c039e313 | 1022 | mutex_lock(&bdev->bd_contains->bd_mutex); |
1da177e4 | 1023 | bdev->bd_contains->bd_part_count--; |
c039e313 | 1024 | mutex_unlock(&bdev->bd_contains->bd_mutex); |
1da177e4 LT |
1025 | } |
1026 | if (!bdev->bd_openers) { | |
1027 | struct module *owner = disk->fops->owner; | |
1028 | ||
1029 | put_disk(disk); | |
1030 | module_put(owner); | |
1031 | ||
1032 | if (bdev->bd_contains != bdev) { | |
1033 | kobject_put(&bdev->bd_part->kobj); | |
1034 | bdev->bd_part = NULL; | |
1035 | } | |
1036 | bdev->bd_disk = NULL; | |
1037 | bdev->bd_inode->i_data.backing_dev_info = &default_backing_dev_info; | |
1038 | if (bdev != bdev->bd_contains) { | |
1039 | blkdev_put(bdev->bd_contains); | |
1040 | } | |
1041 | bdev->bd_contains = NULL; | |
1042 | } | |
1043 | unlock_kernel(); | |
c039e313 | 1044 | mutex_unlock(&bdev->bd_mutex); |
1da177e4 LT |
1045 | bdput(bdev); |
1046 | return ret; | |
1047 | } | |
1048 | ||
1049 | EXPORT_SYMBOL(blkdev_put); | |
1050 | ||
1051 | static int blkdev_close(struct inode * inode, struct file * filp) | |
1052 | { | |
1053 | struct block_device *bdev = I_BDEV(filp->f_mapping->host); | |
1054 | if (bdev->bd_holder == filp) | |
1055 | bd_release(bdev); | |
1056 | return blkdev_put(bdev); | |
1057 | } | |
1058 | ||
1059 | static ssize_t blkdev_file_write(struct file *file, const char __user *buf, | |
1060 | size_t count, loff_t *ppos) | |
1061 | { | |
1062 | struct iovec local_iov = { .iov_base = (void __user *)buf, .iov_len = count }; | |
1063 | ||
1064 | return generic_file_write_nolock(file, &local_iov, 1, ppos); | |
1065 | } | |
1066 | ||
1067 | static ssize_t blkdev_file_aio_write(struct kiocb *iocb, const char __user *buf, | |
1068 | size_t count, loff_t pos) | |
1069 | { | |
1070 | struct iovec local_iov = { .iov_base = (void __user *)buf, .iov_len = count }; | |
1071 | ||
1072 | return generic_file_aio_write_nolock(iocb, &local_iov, 1, &iocb->ki_pos); | |
1073 | } | |
1074 | ||
bb93e3a5 | 1075 | static long block_ioctl(struct file *file, unsigned cmd, unsigned long arg) |
1da177e4 LT |
1076 | { |
1077 | return blkdev_ioctl(file->f_mapping->host, file, cmd, arg); | |
1078 | } | |
1079 | ||
1080 | struct address_space_operations def_blk_aops = { | |
1081 | .readpage = blkdev_readpage, | |
1082 | .writepage = blkdev_writepage, | |
1083 | .sync_page = block_sync_page, | |
1084 | .prepare_write = blkdev_prepare_write, | |
1085 | .commit_write = blkdev_commit_write, | |
1086 | .writepages = generic_writepages, | |
1087 | .direct_IO = blkdev_direct_IO, | |
1088 | }; | |
1089 | ||
4b6f5d20 | 1090 | const struct file_operations def_blk_fops = { |
1da177e4 LT |
1091 | .open = blkdev_open, |
1092 | .release = blkdev_close, | |
1093 | .llseek = block_llseek, | |
1094 | .read = generic_file_read, | |
1095 | .write = blkdev_file_write, | |
1096 | .aio_read = generic_file_aio_read, | |
1097 | .aio_write = blkdev_file_aio_write, | |
1098 | .mmap = generic_file_mmap, | |
1099 | .fsync = block_fsync, | |
bb93e3a5 | 1100 | .unlocked_ioctl = block_ioctl, |
1da177e4 LT |
1101 | #ifdef CONFIG_COMPAT |
1102 | .compat_ioctl = compat_blkdev_ioctl, | |
1103 | #endif | |
1104 | .readv = generic_file_readv, | |
1105 | .writev = generic_file_write_nolock, | |
1106 | .sendfile = generic_file_sendfile, | |
7f9c51f0 JA |
1107 | .splice_read = generic_file_splice_read, |
1108 | .splice_write = generic_file_splice_write, | |
1da177e4 LT |
1109 | }; |
1110 | ||
1111 | int ioctl_by_bdev(struct block_device *bdev, unsigned cmd, unsigned long arg) | |
1112 | { | |
1113 | int res; | |
1114 | mm_segment_t old_fs = get_fs(); | |
1115 | set_fs(KERNEL_DS); | |
1116 | res = blkdev_ioctl(bdev->bd_inode, NULL, cmd, arg); | |
1117 | set_fs(old_fs); | |
1118 | return res; | |
1119 | } | |
1120 | ||
1121 | EXPORT_SYMBOL(ioctl_by_bdev); | |
1122 | ||
1123 | /** | |
1124 | * lookup_bdev - lookup a struct block_device by name | |
1125 | * | |
1126 | * @path: special file representing the block device | |
1127 | * | |
1128 | * Get a reference to the blockdevice at @path in the current | |
1129 | * namespace if possible and return it. Return ERR_PTR(error) | |
1130 | * otherwise. | |
1131 | */ | |
1132 | struct block_device *lookup_bdev(const char *path) | |
1133 | { | |
1134 | struct block_device *bdev; | |
1135 | struct inode *inode; | |
1136 | struct nameidata nd; | |
1137 | int error; | |
1138 | ||
1139 | if (!path || !*path) | |
1140 | return ERR_PTR(-EINVAL); | |
1141 | ||
1142 | error = path_lookup(path, LOOKUP_FOLLOW, &nd); | |
1143 | if (error) | |
1144 | return ERR_PTR(error); | |
1145 | ||
1146 | inode = nd.dentry->d_inode; | |
1147 | error = -ENOTBLK; | |
1148 | if (!S_ISBLK(inode->i_mode)) | |
1149 | goto fail; | |
1150 | error = -EACCES; | |
1151 | if (nd.mnt->mnt_flags & MNT_NODEV) | |
1152 | goto fail; | |
1153 | error = -ENOMEM; | |
1154 | bdev = bd_acquire(inode); | |
1155 | if (!bdev) | |
1156 | goto fail; | |
1157 | out: | |
1158 | path_release(&nd); | |
1159 | return bdev; | |
1160 | fail: | |
1161 | bdev = ERR_PTR(error); | |
1162 | goto out; | |
1163 | } | |
1164 | ||
1165 | /** | |
1166 | * open_bdev_excl - open a block device by name and set it up for use | |
1167 | * | |
1168 | * @path: special file representing the block device | |
1169 | * @flags: %MS_RDONLY for opening read-only | |
1170 | * @holder: owner for exclusion | |
1171 | * | |
1172 | * Open the blockdevice described by the special file at @path, claim it | |
1173 | * for the @holder. | |
1174 | */ | |
1175 | struct block_device *open_bdev_excl(const char *path, int flags, void *holder) | |
1176 | { | |
1177 | struct block_device *bdev; | |
1178 | mode_t mode = FMODE_READ; | |
1179 | int error = 0; | |
1180 | ||
1181 | bdev = lookup_bdev(path); | |
1182 | if (IS_ERR(bdev)) | |
1183 | return bdev; | |
1184 | ||
1185 | if (!(flags & MS_RDONLY)) | |
1186 | mode |= FMODE_WRITE; | |
1187 | error = blkdev_get(bdev, mode, 0); | |
1188 | if (error) | |
1189 | return ERR_PTR(error); | |
1190 | error = -EACCES; | |
1191 | if (!(flags & MS_RDONLY) && bdev_read_only(bdev)) | |
1192 | goto blkdev_put; | |
1193 | error = bd_claim(bdev, holder); | |
1194 | if (error) | |
1195 | goto blkdev_put; | |
1196 | ||
1197 | return bdev; | |
1198 | ||
1199 | blkdev_put: | |
1200 | blkdev_put(bdev); | |
1201 | return ERR_PTR(error); | |
1202 | } | |
1203 | ||
1204 | EXPORT_SYMBOL(open_bdev_excl); | |
1205 | ||
1206 | /** | |
1207 | * close_bdev_excl - release a blockdevice openen by open_bdev_excl() | |
1208 | * | |
1209 | * @bdev: blockdevice to close | |
1210 | * | |
1211 | * This is the counterpart to open_bdev_excl(). | |
1212 | */ | |
1213 | void close_bdev_excl(struct block_device *bdev) | |
1214 | { | |
1215 | bd_release(bdev); | |
1216 | blkdev_put(bdev); | |
1217 | } | |
1218 | ||
1219 | EXPORT_SYMBOL(close_bdev_excl); |