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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/init.h> | |
9 | #include <linux/mm.h> | |
10 | #include <linux/fcntl.h> | |
11 | #include <linux/slab.h> | |
12 | #include <linux/kmod.h> | |
13 | #include <linux/major.h> | |
14 | #include <linux/smp_lock.h> | |
15 | #include <linux/device_cgroup.h> | |
16 | #include <linux/highmem.h> | |
17 | #include <linux/blkdev.h> | |
18 | #include <linux/module.h> | |
19 | #include <linux/blkpg.h> | |
20 | #include <linux/buffer_head.h> | |
21 | #include <linux/pagevec.h> | |
22 | #include <linux/writeback.h> | |
23 | #include <linux/mpage.h> | |
24 | #include <linux/mount.h> | |
25 | #include <linux/uio.h> | |
26 | #include <linux/namei.h> | |
27 | #include <linux/log2.h> | |
28 | #include <linux/kmemleak.h> | |
29 | #include <asm/uaccess.h> | |
30 | #include "internal.h" | |
31 | ||
32 | struct bdev_inode { | |
33 | struct block_device bdev; | |
34 | struct inode vfs_inode; | |
35 | }; | |
36 | ||
37 | static const struct address_space_operations def_blk_aops; | |
38 | ||
39 | static inline struct bdev_inode *BDEV_I(struct inode *inode) | |
40 | { | |
41 | return container_of(inode, struct bdev_inode, vfs_inode); | |
42 | } | |
43 | ||
44 | inline struct block_device *I_BDEV(struct inode *inode) | |
45 | { | |
46 | return &BDEV_I(inode)->bdev; | |
47 | } | |
48 | ||
49 | EXPORT_SYMBOL(I_BDEV); | |
50 | ||
51 | static sector_t max_block(struct block_device *bdev) | |
52 | { | |
53 | sector_t retval = ~((sector_t)0); | |
54 | loff_t sz = i_size_read(bdev->bd_inode); | |
55 | ||
56 | if (sz) { | |
57 | unsigned int size = block_size(bdev); | |
58 | unsigned int sizebits = blksize_bits(size); | |
59 | retval = (sz >> sizebits); | |
60 | } | |
61 | return retval; | |
62 | } | |
63 | ||
64 | /* Kill _all_ buffers and pagecache , dirty or not.. */ | |
65 | static void kill_bdev(struct block_device *bdev) | |
66 | { | |
67 | if (bdev->bd_inode->i_mapping->nrpages == 0) | |
68 | return; | |
69 | invalidate_bh_lrus(); | |
70 | truncate_inode_pages(bdev->bd_inode->i_mapping, 0); | |
71 | } | |
72 | ||
73 | int set_blocksize(struct block_device *bdev, int size) | |
74 | { | |
75 | /* Size must be a power of two, and between 512 and PAGE_SIZE */ | |
76 | if (size > PAGE_SIZE || size < 512 || !is_power_of_2(size)) | |
77 | return -EINVAL; | |
78 | ||
79 | /* Size cannot be smaller than the size supported by the device */ | |
80 | if (size < bdev_logical_block_size(bdev)) | |
81 | return -EINVAL; | |
82 | ||
83 | /* Don't change the size if it is same as current */ | |
84 | if (bdev->bd_block_size != size) { | |
85 | sync_blockdev(bdev); | |
86 | bdev->bd_block_size = size; | |
87 | bdev->bd_inode->i_blkbits = blksize_bits(size); | |
88 | kill_bdev(bdev); | |
89 | } | |
90 | return 0; | |
91 | } | |
92 | ||
93 | EXPORT_SYMBOL(set_blocksize); | |
94 | ||
95 | int sb_set_blocksize(struct super_block *sb, int size) | |
96 | { | |
97 | if (set_blocksize(sb->s_bdev, size)) | |
98 | return 0; | |
99 | /* If we get here, we know size is power of two | |
100 | * and it's value is between 512 and PAGE_SIZE */ | |
101 | sb->s_blocksize = size; | |
102 | sb->s_blocksize_bits = blksize_bits(size); | |
103 | return sb->s_blocksize; | |
104 | } | |
105 | ||
106 | EXPORT_SYMBOL(sb_set_blocksize); | |
107 | ||
108 | int sb_min_blocksize(struct super_block *sb, int size) | |
109 | { | |
110 | int minsize = bdev_logical_block_size(sb->s_bdev); | |
111 | if (size < minsize) | |
112 | size = minsize; | |
113 | return sb_set_blocksize(sb, size); | |
114 | } | |
115 | ||
116 | EXPORT_SYMBOL(sb_min_blocksize); | |
117 | ||
118 | static int | |
119 | blkdev_get_block(struct inode *inode, sector_t iblock, | |
120 | struct buffer_head *bh, int create) | |
121 | { | |
122 | if (iblock >= max_block(I_BDEV(inode))) { | |
123 | if (create) | |
124 | return -EIO; | |
125 | ||
126 | /* | |
127 | * for reads, we're just trying to fill a partial page. | |
128 | * return a hole, they will have to call get_block again | |
129 | * before they can fill it, and they will get -EIO at that | |
130 | * time | |
131 | */ | |
132 | return 0; | |
133 | } | |
134 | bh->b_bdev = I_BDEV(inode); | |
135 | bh->b_blocknr = iblock; | |
136 | set_buffer_mapped(bh); | |
137 | return 0; | |
138 | } | |
139 | ||
140 | static int | |
141 | blkdev_get_blocks(struct inode *inode, sector_t iblock, | |
142 | struct buffer_head *bh, int create) | |
143 | { | |
144 | sector_t end_block = max_block(I_BDEV(inode)); | |
145 | unsigned long max_blocks = bh->b_size >> inode->i_blkbits; | |
146 | ||
147 | if ((iblock + max_blocks) > end_block) { | |
148 | max_blocks = end_block - iblock; | |
149 | if ((long)max_blocks <= 0) { | |
150 | if (create) | |
151 | return -EIO; /* write fully beyond EOF */ | |
152 | /* | |
153 | * It is a read which is fully beyond EOF. We return | |
154 | * a !buffer_mapped buffer | |
155 | */ | |
156 | max_blocks = 0; | |
157 | } | |
158 | } | |
159 | ||
160 | bh->b_bdev = I_BDEV(inode); | |
161 | bh->b_blocknr = iblock; | |
162 | bh->b_size = max_blocks << inode->i_blkbits; | |
163 | if (max_blocks) | |
164 | set_buffer_mapped(bh); | |
165 | return 0; | |
166 | } | |
167 | ||
168 | static ssize_t | |
169 | blkdev_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov, | |
170 | loff_t offset, unsigned long nr_segs) | |
171 | { | |
172 | struct file *file = iocb->ki_filp; | |
173 | struct inode *inode = file->f_mapping->host; | |
174 | ||
175 | return blockdev_direct_IO_no_locking(rw, iocb, inode, I_BDEV(inode), | |
176 | iov, offset, nr_segs, blkdev_get_blocks, NULL); | |
177 | } | |
178 | ||
179 | int __sync_blockdev(struct block_device *bdev, int wait) | |
180 | { | |
181 | if (!bdev) | |
182 | return 0; | |
183 | if (!wait) | |
184 | return filemap_flush(bdev->bd_inode->i_mapping); | |
185 | return filemap_write_and_wait(bdev->bd_inode->i_mapping); | |
186 | } | |
187 | ||
188 | /* | |
189 | * Write out and wait upon all the dirty data associated with a block | |
190 | * device via its mapping. Does not take the superblock lock. | |
191 | */ | |
192 | int sync_blockdev(struct block_device *bdev) | |
193 | { | |
194 | return __sync_blockdev(bdev, 1); | |
195 | } | |
196 | EXPORT_SYMBOL(sync_blockdev); | |
197 | ||
198 | /* | |
199 | * Write out and wait upon all dirty data associated with this | |
200 | * device. Filesystem data as well as the underlying block | |
201 | * device. Takes the superblock lock. | |
202 | */ | |
203 | int fsync_bdev(struct block_device *bdev) | |
204 | { | |
205 | struct super_block *sb = get_super(bdev); | |
206 | if (sb) { | |
207 | int res = sync_filesystem(sb); | |
208 | drop_super(sb); | |
209 | return res; | |
210 | } | |
211 | return sync_blockdev(bdev); | |
212 | } | |
213 | EXPORT_SYMBOL(fsync_bdev); | |
214 | ||
215 | /** | |
216 | * freeze_bdev -- lock a filesystem and force it into a consistent state | |
217 | * @bdev: blockdevice to lock | |
218 | * | |
219 | * If a superblock is found on this device, we take the s_umount semaphore | |
220 | * on it to make sure nobody unmounts until the snapshot creation is done. | |
221 | * The reference counter (bd_fsfreeze_count) guarantees that only the last | |
222 | * unfreeze process can unfreeze the frozen filesystem actually when multiple | |
223 | * freeze requests arrive simultaneously. It counts up in freeze_bdev() and | |
224 | * count down in thaw_bdev(). When it becomes 0, thaw_bdev() will unfreeze | |
225 | * actually. | |
226 | */ | |
227 | struct super_block *freeze_bdev(struct block_device *bdev) | |
228 | { | |
229 | struct super_block *sb; | |
230 | int error = 0; | |
231 | ||
232 | mutex_lock(&bdev->bd_fsfreeze_mutex); | |
233 | if (bdev->bd_fsfreeze_count > 0) { | |
234 | bdev->bd_fsfreeze_count++; | |
235 | sb = get_super(bdev); | |
236 | mutex_unlock(&bdev->bd_fsfreeze_mutex); | |
237 | return sb; | |
238 | } | |
239 | bdev->bd_fsfreeze_count++; | |
240 | ||
241 | sb = get_super(bdev); | |
242 | if (sb && !(sb->s_flags & MS_RDONLY)) { | |
243 | sb->s_frozen = SB_FREEZE_WRITE; | |
244 | smp_wmb(); | |
245 | ||
246 | sync_filesystem(sb); | |
247 | ||
248 | sb->s_frozen = SB_FREEZE_TRANS; | |
249 | smp_wmb(); | |
250 | ||
251 | sync_blockdev(sb->s_bdev); | |
252 | ||
253 | if (sb->s_op->freeze_fs) { | |
254 | error = sb->s_op->freeze_fs(sb); | |
255 | if (error) { | |
256 | printk(KERN_ERR | |
257 | "VFS:Filesystem freeze failed\n"); | |
258 | sb->s_frozen = SB_UNFROZEN; | |
259 | drop_super(sb); | |
260 | bdev->bd_fsfreeze_count--; | |
261 | mutex_unlock(&bdev->bd_fsfreeze_mutex); | |
262 | return ERR_PTR(error); | |
263 | } | |
264 | } | |
265 | } | |
266 | ||
267 | sync_blockdev(bdev); | |
268 | mutex_unlock(&bdev->bd_fsfreeze_mutex); | |
269 | ||
270 | return sb; /* thaw_bdev releases s->s_umount */ | |
271 | } | |
272 | EXPORT_SYMBOL(freeze_bdev); | |
273 | ||
274 | /** | |
275 | * thaw_bdev -- unlock filesystem | |
276 | * @bdev: blockdevice to unlock | |
277 | * @sb: associated superblock | |
278 | * | |
279 | * Unlocks the filesystem and marks it writeable again after freeze_bdev(). | |
280 | */ | |
281 | int thaw_bdev(struct block_device *bdev, struct super_block *sb) | |
282 | { | |
283 | int error = 0; | |
284 | ||
285 | mutex_lock(&bdev->bd_fsfreeze_mutex); | |
286 | if (!bdev->bd_fsfreeze_count) { | |
287 | mutex_unlock(&bdev->bd_fsfreeze_mutex); | |
288 | return -EINVAL; | |
289 | } | |
290 | ||
291 | bdev->bd_fsfreeze_count--; | |
292 | if (bdev->bd_fsfreeze_count > 0) { | |
293 | if (sb) | |
294 | drop_super(sb); | |
295 | mutex_unlock(&bdev->bd_fsfreeze_mutex); | |
296 | return 0; | |
297 | } | |
298 | ||
299 | if (sb) { | |
300 | BUG_ON(sb->s_bdev != bdev); | |
301 | if (!(sb->s_flags & MS_RDONLY)) { | |
302 | if (sb->s_op->unfreeze_fs) { | |
303 | error = sb->s_op->unfreeze_fs(sb); | |
304 | if (error) { | |
305 | printk(KERN_ERR | |
306 | "VFS:Filesystem thaw failed\n"); | |
307 | sb->s_frozen = SB_FREEZE_TRANS; | |
308 | bdev->bd_fsfreeze_count++; | |
309 | mutex_unlock(&bdev->bd_fsfreeze_mutex); | |
310 | return error; | |
311 | } | |
312 | } | |
313 | sb->s_frozen = SB_UNFROZEN; | |
314 | smp_wmb(); | |
315 | wake_up(&sb->s_wait_unfrozen); | |
316 | } | |
317 | drop_super(sb); | |
318 | } | |
319 | ||
320 | mutex_unlock(&bdev->bd_fsfreeze_mutex); | |
321 | return 0; | |
322 | } | |
323 | EXPORT_SYMBOL(thaw_bdev); | |
324 | ||
325 | static int blkdev_writepage(struct page *page, struct writeback_control *wbc) | |
326 | { | |
327 | return block_write_full_page(page, blkdev_get_block, wbc); | |
328 | } | |
329 | ||
330 | static int blkdev_readpage(struct file * file, struct page * page) | |
331 | { | |
332 | return block_read_full_page(page, blkdev_get_block); | |
333 | } | |
334 | ||
335 | static int blkdev_write_begin(struct file *file, struct address_space *mapping, | |
336 | loff_t pos, unsigned len, unsigned flags, | |
337 | struct page **pagep, void **fsdata) | |
338 | { | |
339 | *pagep = NULL; | |
340 | return block_write_begin(file, mapping, pos, len, flags, pagep, fsdata, | |
341 | blkdev_get_block); | |
342 | } | |
343 | ||
344 | static int blkdev_write_end(struct file *file, struct address_space *mapping, | |
345 | loff_t pos, unsigned len, unsigned copied, | |
346 | struct page *page, void *fsdata) | |
347 | { | |
348 | int ret; | |
349 | ret = block_write_end(file, mapping, pos, len, copied, page, fsdata); | |
350 | ||
351 | unlock_page(page); | |
352 | page_cache_release(page); | |
353 | ||
354 | return ret; | |
355 | } | |
356 | ||
357 | /* | |
358 | * private llseek: | |
359 | * for a block special file file->f_path.dentry->d_inode->i_size is zero | |
360 | * so we compute the size by hand (just as in block_read/write above) | |
361 | */ | |
362 | static loff_t block_llseek(struct file *file, loff_t offset, int origin) | |
363 | { | |
364 | struct inode *bd_inode = file->f_mapping->host; | |
365 | loff_t size; | |
366 | loff_t retval; | |
367 | ||
368 | mutex_lock(&bd_inode->i_mutex); | |
369 | size = i_size_read(bd_inode); | |
370 | ||
371 | switch (origin) { | |
372 | case 2: | |
373 | offset += size; | |
374 | break; | |
375 | case 1: | |
376 | offset += file->f_pos; | |
377 | } | |
378 | retval = -EINVAL; | |
379 | if (offset >= 0 && offset <= size) { | |
380 | if (offset != file->f_pos) { | |
381 | file->f_pos = offset; | |
382 | } | |
383 | retval = offset; | |
384 | } | |
385 | mutex_unlock(&bd_inode->i_mutex); | |
386 | return retval; | |
387 | } | |
388 | ||
389 | /* | |
390 | * Filp is never NULL; the only case when ->fsync() is called with | |
391 | * NULL first argument is nfsd_sync_dir() and that's not a directory. | |
392 | */ | |
393 | ||
394 | static int block_fsync(struct file *filp, struct dentry *dentry, int datasync) | |
395 | { | |
396 | return sync_blockdev(I_BDEV(filp->f_mapping->host)); | |
397 | } | |
398 | ||
399 | /* | |
400 | * pseudo-fs | |
401 | */ | |
402 | ||
403 | static __cacheline_aligned_in_smp DEFINE_SPINLOCK(bdev_lock); | |
404 | static struct kmem_cache * bdev_cachep __read_mostly; | |
405 | ||
406 | static struct inode *bdev_alloc_inode(struct super_block *sb) | |
407 | { | |
408 | struct bdev_inode *ei = kmem_cache_alloc(bdev_cachep, GFP_KERNEL); | |
409 | if (!ei) | |
410 | return NULL; | |
411 | return &ei->vfs_inode; | |
412 | } | |
413 | ||
414 | static void bdev_destroy_inode(struct inode *inode) | |
415 | { | |
416 | struct bdev_inode *bdi = BDEV_I(inode); | |
417 | ||
418 | kmem_cache_free(bdev_cachep, bdi); | |
419 | } | |
420 | ||
421 | static void init_once(void *foo) | |
422 | { | |
423 | struct bdev_inode *ei = (struct bdev_inode *) foo; | |
424 | struct block_device *bdev = &ei->bdev; | |
425 | ||
426 | memset(bdev, 0, sizeof(*bdev)); | |
427 | mutex_init(&bdev->bd_mutex); | |
428 | INIT_LIST_HEAD(&bdev->bd_inodes); | |
429 | INIT_LIST_HEAD(&bdev->bd_list); | |
430 | #ifdef CONFIG_SYSFS | |
431 | INIT_LIST_HEAD(&bdev->bd_holder_list); | |
432 | #endif | |
433 | inode_init_once(&ei->vfs_inode); | |
434 | /* Initialize mutex for freeze. */ | |
435 | mutex_init(&bdev->bd_fsfreeze_mutex); | |
436 | } | |
437 | ||
438 | static inline void __bd_forget(struct inode *inode) | |
439 | { | |
440 | list_del_init(&inode->i_devices); | |
441 | inode->i_bdev = NULL; | |
442 | inode->i_mapping = &inode->i_data; | |
443 | } | |
444 | ||
445 | static void bdev_clear_inode(struct inode *inode) | |
446 | { | |
447 | struct block_device *bdev = &BDEV_I(inode)->bdev; | |
448 | struct list_head *p; | |
449 | spin_lock(&bdev_lock); | |
450 | while ( (p = bdev->bd_inodes.next) != &bdev->bd_inodes ) { | |
451 | __bd_forget(list_entry(p, struct inode, i_devices)); | |
452 | } | |
453 | list_del_init(&bdev->bd_list); | |
454 | spin_unlock(&bdev_lock); | |
455 | } | |
456 | ||
457 | static const struct super_operations bdev_sops = { | |
458 | .statfs = simple_statfs, | |
459 | .alloc_inode = bdev_alloc_inode, | |
460 | .destroy_inode = bdev_destroy_inode, | |
461 | .drop_inode = generic_delete_inode, | |
462 | .clear_inode = bdev_clear_inode, | |
463 | }; | |
464 | ||
465 | static int bd_get_sb(struct file_system_type *fs_type, | |
466 | int flags, const char *dev_name, void *data, struct vfsmount *mnt) | |
467 | { | |
468 | return get_sb_pseudo(fs_type, "bdev:", &bdev_sops, 0x62646576, mnt); | |
469 | } | |
470 | ||
471 | static struct file_system_type bd_type = { | |
472 | .name = "bdev", | |
473 | .get_sb = bd_get_sb, | |
474 | .kill_sb = kill_anon_super, | |
475 | }; | |
476 | ||
477 | struct super_block *blockdev_superblock __read_mostly; | |
478 | ||
479 | void __init bdev_cache_init(void) | |
480 | { | |
481 | int err; | |
482 | struct vfsmount *bd_mnt; | |
483 | ||
484 | bdev_cachep = kmem_cache_create("bdev_cache", sizeof(struct bdev_inode), | |
485 | 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT| | |
486 | SLAB_MEM_SPREAD|SLAB_PANIC), | |
487 | init_once); | |
488 | err = register_filesystem(&bd_type); | |
489 | if (err) | |
490 | panic("Cannot register bdev pseudo-fs"); | |
491 | bd_mnt = kern_mount(&bd_type); | |
492 | if (IS_ERR(bd_mnt)) | |
493 | panic("Cannot create bdev pseudo-fs"); | |
494 | /* | |
495 | * This vfsmount structure is only used to obtain the | |
496 | * blockdev_superblock, so tell kmemleak not to report it. | |
497 | */ | |
498 | kmemleak_not_leak(bd_mnt); | |
499 | blockdev_superblock = bd_mnt->mnt_sb; /* For writeback */ | |
500 | } | |
501 | ||
502 | /* | |
503 | * Most likely _very_ bad one - but then it's hardly critical for small | |
504 | * /dev and can be fixed when somebody will need really large one. | |
505 | * Keep in mind that it will be fed through icache hash function too. | |
506 | */ | |
507 | static inline unsigned long hash(dev_t dev) | |
508 | { | |
509 | return MAJOR(dev)+MINOR(dev); | |
510 | } | |
511 | ||
512 | static int bdev_test(struct inode *inode, void *data) | |
513 | { | |
514 | return BDEV_I(inode)->bdev.bd_dev == *(dev_t *)data; | |
515 | } | |
516 | ||
517 | static int bdev_set(struct inode *inode, void *data) | |
518 | { | |
519 | BDEV_I(inode)->bdev.bd_dev = *(dev_t *)data; | |
520 | return 0; | |
521 | } | |
522 | ||
523 | static LIST_HEAD(all_bdevs); | |
524 | ||
525 | struct block_device *bdget(dev_t dev) | |
526 | { | |
527 | struct block_device *bdev; | |
528 | struct inode *inode; | |
529 | ||
530 | inode = iget5_locked(blockdev_superblock, hash(dev), | |
531 | bdev_test, bdev_set, &dev); | |
532 | ||
533 | if (!inode) | |
534 | return NULL; | |
535 | ||
536 | bdev = &BDEV_I(inode)->bdev; | |
537 | ||
538 | if (inode->i_state & I_NEW) { | |
539 | bdev->bd_contains = NULL; | |
540 | bdev->bd_inode = inode; | |
541 | bdev->bd_block_size = (1 << inode->i_blkbits); | |
542 | bdev->bd_part_count = 0; | |
543 | bdev->bd_invalidated = 0; | |
544 | inode->i_mode = S_IFBLK; | |
545 | inode->i_rdev = dev; | |
546 | inode->i_bdev = bdev; | |
547 | inode->i_data.a_ops = &def_blk_aops; | |
548 | mapping_set_gfp_mask(&inode->i_data, GFP_USER); | |
549 | inode->i_data.backing_dev_info = &default_backing_dev_info; | |
550 | spin_lock(&bdev_lock); | |
551 | list_add(&bdev->bd_list, &all_bdevs); | |
552 | spin_unlock(&bdev_lock); | |
553 | unlock_new_inode(inode); | |
554 | } | |
555 | return bdev; | |
556 | } | |
557 | ||
558 | EXPORT_SYMBOL(bdget); | |
559 | ||
560 | /** | |
561 | * bdgrab -- Grab a reference to an already referenced block device | |
562 | * @bdev: Block device to grab a reference to. | |
563 | */ | |
564 | struct block_device *bdgrab(struct block_device *bdev) | |
565 | { | |
566 | atomic_inc(&bdev->bd_inode->i_count); | |
567 | return bdev; | |
568 | } | |
569 | ||
570 | long nr_blockdev_pages(void) | |
571 | { | |
572 | struct block_device *bdev; | |
573 | long ret = 0; | |
574 | spin_lock(&bdev_lock); | |
575 | list_for_each_entry(bdev, &all_bdevs, bd_list) { | |
576 | ret += bdev->bd_inode->i_mapping->nrpages; | |
577 | } | |
578 | spin_unlock(&bdev_lock); | |
579 | return ret; | |
580 | } | |
581 | ||
582 | void bdput(struct block_device *bdev) | |
583 | { | |
584 | iput(bdev->bd_inode); | |
585 | } | |
586 | ||
587 | EXPORT_SYMBOL(bdput); | |
588 | ||
589 | static struct block_device *bd_acquire(struct inode *inode) | |
590 | { | |
591 | struct block_device *bdev; | |
592 | ||
593 | spin_lock(&bdev_lock); | |
594 | bdev = inode->i_bdev; | |
595 | if (bdev) { | |
596 | atomic_inc(&bdev->bd_inode->i_count); | |
597 | spin_unlock(&bdev_lock); | |
598 | return bdev; | |
599 | } | |
600 | spin_unlock(&bdev_lock); | |
601 | ||
602 | bdev = bdget(inode->i_rdev); | |
603 | if (bdev) { | |
604 | spin_lock(&bdev_lock); | |
605 | if (!inode->i_bdev) { | |
606 | /* | |
607 | * We take an additional bd_inode->i_count for inode, | |
608 | * and it's released in clear_inode() of inode. | |
609 | * So, we can access it via ->i_mapping always | |
610 | * without igrab(). | |
611 | */ | |
612 | atomic_inc(&bdev->bd_inode->i_count); | |
613 | inode->i_bdev = bdev; | |
614 | inode->i_mapping = bdev->bd_inode->i_mapping; | |
615 | list_add(&inode->i_devices, &bdev->bd_inodes); | |
616 | } | |
617 | spin_unlock(&bdev_lock); | |
618 | } | |
619 | return bdev; | |
620 | } | |
621 | ||
622 | /* Call when you free inode */ | |
623 | ||
624 | void bd_forget(struct inode *inode) | |
625 | { | |
626 | struct block_device *bdev = NULL; | |
627 | ||
628 | spin_lock(&bdev_lock); | |
629 | if (inode->i_bdev) { | |
630 | if (!sb_is_blkdev_sb(inode->i_sb)) | |
631 | bdev = inode->i_bdev; | |
632 | __bd_forget(inode); | |
633 | } | |
634 | spin_unlock(&bdev_lock); | |
635 | ||
636 | if (bdev) | |
637 | iput(bdev->bd_inode); | |
638 | } | |
639 | ||
640 | int bd_claim(struct block_device *bdev, void *holder) | |
641 | { | |
642 | int res; | |
643 | spin_lock(&bdev_lock); | |
644 | ||
645 | /* first decide result */ | |
646 | if (bdev->bd_holder == holder) | |
647 | res = 0; /* already a holder */ | |
648 | else if (bdev->bd_holder != NULL) | |
649 | res = -EBUSY; /* held by someone else */ | |
650 | else if (bdev->bd_contains == bdev) | |
651 | res = 0; /* is a whole device which isn't held */ | |
652 | ||
653 | else if (bdev->bd_contains->bd_holder == bd_claim) | |
654 | res = 0; /* is a partition of a device that is being partitioned */ | |
655 | else if (bdev->bd_contains->bd_holder != NULL) | |
656 | res = -EBUSY; /* is a partition of a held device */ | |
657 | else | |
658 | res = 0; /* is a partition of an un-held device */ | |
659 | ||
660 | /* now impose change */ | |
661 | if (res==0) { | |
662 | /* note that for a whole device bd_holders | |
663 | * will be incremented twice, and bd_holder will | |
664 | * be set to bd_claim before being set to holder | |
665 | */ | |
666 | bdev->bd_contains->bd_holders ++; | |
667 | bdev->bd_contains->bd_holder = bd_claim; | |
668 | bdev->bd_holders++; | |
669 | bdev->bd_holder = holder; | |
670 | } | |
671 | spin_unlock(&bdev_lock); | |
672 | return res; | |
673 | } | |
674 | ||
675 | EXPORT_SYMBOL(bd_claim); | |
676 | ||
677 | void bd_release(struct block_device *bdev) | |
678 | { | |
679 | spin_lock(&bdev_lock); | |
680 | if (!--bdev->bd_contains->bd_holders) | |
681 | bdev->bd_contains->bd_holder = NULL; | |
682 | if (!--bdev->bd_holders) | |
683 | bdev->bd_holder = NULL; | |
684 | spin_unlock(&bdev_lock); | |
685 | } | |
686 | ||
687 | EXPORT_SYMBOL(bd_release); | |
688 | ||
689 | #ifdef CONFIG_SYSFS | |
690 | /* | |
691 | * Functions for bd_claim_by_kobject / bd_release_from_kobject | |
692 | * | |
693 | * If a kobject is passed to bd_claim_by_kobject() | |
694 | * and the kobject has a parent directory, | |
695 | * following symlinks are created: | |
696 | * o from the kobject to the claimed bdev | |
697 | * o from "holders" directory of the bdev to the parent of the kobject | |
698 | * bd_release_from_kobject() removes these symlinks. | |
699 | * | |
700 | * Example: | |
701 | * If /dev/dm-0 maps to /dev/sda, kobject corresponding to | |
702 | * /sys/block/dm-0/slaves is passed to bd_claim_by_kobject(), then: | |
703 | * /sys/block/dm-0/slaves/sda --> /sys/block/sda | |
704 | * /sys/block/sda/holders/dm-0 --> /sys/block/dm-0 | |
705 | */ | |
706 | ||
707 | static int add_symlink(struct kobject *from, struct kobject *to) | |
708 | { | |
709 | if (!from || !to) | |
710 | return 0; | |
711 | return sysfs_create_link(from, to, kobject_name(to)); | |
712 | } | |
713 | ||
714 | static void del_symlink(struct kobject *from, struct kobject *to) | |
715 | { | |
716 | if (!from || !to) | |
717 | return; | |
718 | sysfs_remove_link(from, kobject_name(to)); | |
719 | } | |
720 | ||
721 | /* | |
722 | * 'struct bd_holder' contains pointers to kobjects symlinked by | |
723 | * bd_claim_by_kobject. | |
724 | * It's connected to bd_holder_list which is protected by bdev->bd_sem. | |
725 | */ | |
726 | struct bd_holder { | |
727 | struct list_head list; /* chain of holders of the bdev */ | |
728 | int count; /* references from the holder */ | |
729 | struct kobject *sdir; /* holder object, e.g. "/block/dm-0/slaves" */ | |
730 | struct kobject *hdev; /* e.g. "/block/dm-0" */ | |
731 | struct kobject *hdir; /* e.g. "/block/sda/holders" */ | |
732 | struct kobject *sdev; /* e.g. "/block/sda" */ | |
733 | }; | |
734 | ||
735 | /* | |
736 | * Get references of related kobjects at once. | |
737 | * Returns 1 on success. 0 on failure. | |
738 | * | |
739 | * Should call bd_holder_release_dirs() after successful use. | |
740 | */ | |
741 | static int bd_holder_grab_dirs(struct block_device *bdev, | |
742 | struct bd_holder *bo) | |
743 | { | |
744 | if (!bdev || !bo) | |
745 | return 0; | |
746 | ||
747 | bo->sdir = kobject_get(bo->sdir); | |
748 | if (!bo->sdir) | |
749 | return 0; | |
750 | ||
751 | bo->hdev = kobject_get(bo->sdir->parent); | |
752 | if (!bo->hdev) | |
753 | goto fail_put_sdir; | |
754 | ||
755 | bo->sdev = kobject_get(&part_to_dev(bdev->bd_part)->kobj); | |
756 | if (!bo->sdev) | |
757 | goto fail_put_hdev; | |
758 | ||
759 | bo->hdir = kobject_get(bdev->bd_part->holder_dir); | |
760 | if (!bo->hdir) | |
761 | goto fail_put_sdev; | |
762 | ||
763 | return 1; | |
764 | ||
765 | fail_put_sdev: | |
766 | kobject_put(bo->sdev); | |
767 | fail_put_hdev: | |
768 | kobject_put(bo->hdev); | |
769 | fail_put_sdir: | |
770 | kobject_put(bo->sdir); | |
771 | ||
772 | return 0; | |
773 | } | |
774 | ||
775 | /* Put references of related kobjects at once. */ | |
776 | static void bd_holder_release_dirs(struct bd_holder *bo) | |
777 | { | |
778 | kobject_put(bo->hdir); | |
779 | kobject_put(bo->sdev); | |
780 | kobject_put(bo->hdev); | |
781 | kobject_put(bo->sdir); | |
782 | } | |
783 | ||
784 | static struct bd_holder *alloc_bd_holder(struct kobject *kobj) | |
785 | { | |
786 | struct bd_holder *bo; | |
787 | ||
788 | bo = kzalloc(sizeof(*bo), GFP_KERNEL); | |
789 | if (!bo) | |
790 | return NULL; | |
791 | ||
792 | bo->count = 1; | |
793 | bo->sdir = kobj; | |
794 | ||
795 | return bo; | |
796 | } | |
797 | ||
798 | static void free_bd_holder(struct bd_holder *bo) | |
799 | { | |
800 | kfree(bo); | |
801 | } | |
802 | ||
803 | /** | |
804 | * find_bd_holder - find matching struct bd_holder from the block device | |
805 | * | |
806 | * @bdev: struct block device to be searched | |
807 | * @bo: target struct bd_holder | |
808 | * | |
809 | * Returns matching entry with @bo in @bdev->bd_holder_list. | |
810 | * If found, increment the reference count and return the pointer. | |
811 | * If not found, returns NULL. | |
812 | */ | |
813 | static struct bd_holder *find_bd_holder(struct block_device *bdev, | |
814 | struct bd_holder *bo) | |
815 | { | |
816 | struct bd_holder *tmp; | |
817 | ||
818 | list_for_each_entry(tmp, &bdev->bd_holder_list, list) | |
819 | if (tmp->sdir == bo->sdir) { | |
820 | tmp->count++; | |
821 | return tmp; | |
822 | } | |
823 | ||
824 | return NULL; | |
825 | } | |
826 | ||
827 | /** | |
828 | * add_bd_holder - create sysfs symlinks for bd_claim() relationship | |
829 | * | |
830 | * @bdev: block device to be bd_claimed | |
831 | * @bo: preallocated and initialized by alloc_bd_holder() | |
832 | * | |
833 | * Add @bo to @bdev->bd_holder_list, create symlinks. | |
834 | * | |
835 | * Returns 0 if symlinks are created. | |
836 | * Returns -ve if something fails. | |
837 | */ | |
838 | static int add_bd_holder(struct block_device *bdev, struct bd_holder *bo) | |
839 | { | |
840 | int err; | |
841 | ||
842 | if (!bo) | |
843 | return -EINVAL; | |
844 | ||
845 | if (!bd_holder_grab_dirs(bdev, bo)) | |
846 | return -EBUSY; | |
847 | ||
848 | err = add_symlink(bo->sdir, bo->sdev); | |
849 | if (err) | |
850 | return err; | |
851 | ||
852 | err = add_symlink(bo->hdir, bo->hdev); | |
853 | if (err) { | |
854 | del_symlink(bo->sdir, bo->sdev); | |
855 | return err; | |
856 | } | |
857 | ||
858 | list_add_tail(&bo->list, &bdev->bd_holder_list); | |
859 | return 0; | |
860 | } | |
861 | ||
862 | /** | |
863 | * del_bd_holder - delete sysfs symlinks for bd_claim() relationship | |
864 | * | |
865 | * @bdev: block device to be bd_claimed | |
866 | * @kobj: holder's kobject | |
867 | * | |
868 | * If there is matching entry with @kobj in @bdev->bd_holder_list | |
869 | * and no other bd_claim() from the same kobject, | |
870 | * remove the struct bd_holder from the list, delete symlinks for it. | |
871 | * | |
872 | * Returns a pointer to the struct bd_holder when it's removed from the list | |
873 | * and ready to be freed. | |
874 | * Returns NULL if matching claim isn't found or there is other bd_claim() | |
875 | * by the same kobject. | |
876 | */ | |
877 | static struct bd_holder *del_bd_holder(struct block_device *bdev, | |
878 | struct kobject *kobj) | |
879 | { | |
880 | struct bd_holder *bo; | |
881 | ||
882 | list_for_each_entry(bo, &bdev->bd_holder_list, list) { | |
883 | if (bo->sdir == kobj) { | |
884 | bo->count--; | |
885 | BUG_ON(bo->count < 0); | |
886 | if (!bo->count) { | |
887 | list_del(&bo->list); | |
888 | del_symlink(bo->sdir, bo->sdev); | |
889 | del_symlink(bo->hdir, bo->hdev); | |
890 | bd_holder_release_dirs(bo); | |
891 | return bo; | |
892 | } | |
893 | break; | |
894 | } | |
895 | } | |
896 | ||
897 | return NULL; | |
898 | } | |
899 | ||
900 | /** | |
901 | * bd_claim_by_kobject - bd_claim() with additional kobject signature | |
902 | * | |
903 | * @bdev: block device to be claimed | |
904 | * @holder: holder's signature | |
905 | * @kobj: holder's kobject | |
906 | * | |
907 | * Do bd_claim() and if it succeeds, create sysfs symlinks between | |
908 | * the bdev and the holder's kobject. | |
909 | * Use bd_release_from_kobject() when relesing the claimed bdev. | |
910 | * | |
911 | * Returns 0 on success. (same as bd_claim()) | |
912 | * Returns errno on failure. | |
913 | */ | |
914 | static int bd_claim_by_kobject(struct block_device *bdev, void *holder, | |
915 | struct kobject *kobj) | |
916 | { | |
917 | int err; | |
918 | struct bd_holder *bo, *found; | |
919 | ||
920 | if (!kobj) | |
921 | return -EINVAL; | |
922 | ||
923 | bo = alloc_bd_holder(kobj); | |
924 | if (!bo) | |
925 | return -ENOMEM; | |
926 | ||
927 | mutex_lock(&bdev->bd_mutex); | |
928 | ||
929 | err = bd_claim(bdev, holder); | |
930 | if (err) | |
931 | goto fail; | |
932 | ||
933 | found = find_bd_holder(bdev, bo); | |
934 | if (found) | |
935 | goto fail; | |
936 | ||
937 | err = add_bd_holder(bdev, bo); | |
938 | if (err) | |
939 | bd_release(bdev); | |
940 | else | |
941 | bo = NULL; | |
942 | fail: | |
943 | mutex_unlock(&bdev->bd_mutex); | |
944 | free_bd_holder(bo); | |
945 | return err; | |
946 | } | |
947 | ||
948 | /** | |
949 | * bd_release_from_kobject - bd_release() with additional kobject signature | |
950 | * | |
951 | * @bdev: block device to be released | |
952 | * @kobj: holder's kobject | |
953 | * | |
954 | * Do bd_release() and remove sysfs symlinks created by bd_claim_by_kobject(). | |
955 | */ | |
956 | static void bd_release_from_kobject(struct block_device *bdev, | |
957 | struct kobject *kobj) | |
958 | { | |
959 | if (!kobj) | |
960 | return; | |
961 | ||
962 | mutex_lock(&bdev->bd_mutex); | |
963 | bd_release(bdev); | |
964 | free_bd_holder(del_bd_holder(bdev, kobj)); | |
965 | mutex_unlock(&bdev->bd_mutex); | |
966 | } | |
967 | ||
968 | /** | |
969 | * bd_claim_by_disk - wrapper function for bd_claim_by_kobject() | |
970 | * | |
971 | * @bdev: block device to be claimed | |
972 | * @holder: holder's signature | |
973 | * @disk: holder's gendisk | |
974 | * | |
975 | * Call bd_claim_by_kobject() with getting @disk->slave_dir. | |
976 | */ | |
977 | int bd_claim_by_disk(struct block_device *bdev, void *holder, | |
978 | struct gendisk *disk) | |
979 | { | |
980 | return bd_claim_by_kobject(bdev, holder, kobject_get(disk->slave_dir)); | |
981 | } | |
982 | EXPORT_SYMBOL_GPL(bd_claim_by_disk); | |
983 | ||
984 | /** | |
985 | * bd_release_from_disk - wrapper function for bd_release_from_kobject() | |
986 | * | |
987 | * @bdev: block device to be claimed | |
988 | * @disk: holder's gendisk | |
989 | * | |
990 | * Call bd_release_from_kobject() and put @disk->slave_dir. | |
991 | */ | |
992 | void bd_release_from_disk(struct block_device *bdev, struct gendisk *disk) | |
993 | { | |
994 | bd_release_from_kobject(bdev, disk->slave_dir); | |
995 | kobject_put(disk->slave_dir); | |
996 | } | |
997 | EXPORT_SYMBOL_GPL(bd_release_from_disk); | |
998 | #endif | |
999 | ||
1000 | /* | |
1001 | * Tries to open block device by device number. Use it ONLY if you | |
1002 | * really do not have anything better - i.e. when you are behind a | |
1003 | * truly sucky interface and all you are given is a device number. _Never_ | |
1004 | * to be used for internal purposes. If you ever need it - reconsider | |
1005 | * your API. | |
1006 | */ | |
1007 | struct block_device *open_by_devnum(dev_t dev, fmode_t mode) | |
1008 | { | |
1009 | struct block_device *bdev = bdget(dev); | |
1010 | int err = -ENOMEM; | |
1011 | if (bdev) | |
1012 | err = blkdev_get(bdev, mode); | |
1013 | return err ? ERR_PTR(err) : bdev; | |
1014 | } | |
1015 | ||
1016 | EXPORT_SYMBOL(open_by_devnum); | |
1017 | ||
1018 | /** | |
1019 | * flush_disk - invalidates all buffer-cache entries on a disk | |
1020 | * | |
1021 | * @bdev: struct block device to be flushed | |
1022 | * | |
1023 | * Invalidates all buffer-cache entries on a disk. It should be called | |
1024 | * when a disk has been changed -- either by a media change or online | |
1025 | * resize. | |
1026 | */ | |
1027 | static void flush_disk(struct block_device *bdev) | |
1028 | { | |
1029 | if (__invalidate_device(bdev)) { | |
1030 | char name[BDEVNAME_SIZE] = ""; | |
1031 | ||
1032 | if (bdev->bd_disk) | |
1033 | disk_name(bdev->bd_disk, 0, name); | |
1034 | printk(KERN_WARNING "VFS: busy inodes on changed media or " | |
1035 | "resized disk %s\n", name); | |
1036 | } | |
1037 | ||
1038 | if (!bdev->bd_disk) | |
1039 | return; | |
1040 | if (disk_partitionable(bdev->bd_disk)) | |
1041 | bdev->bd_invalidated = 1; | |
1042 | } | |
1043 | ||
1044 | /** | |
1045 | * check_disk_size_change - checks for disk size change and adjusts bdev size. | |
1046 | * @disk: struct gendisk to check | |
1047 | * @bdev: struct bdev to adjust. | |
1048 | * | |
1049 | * This routine checks to see if the bdev size does not match the disk size | |
1050 | * and adjusts it if it differs. | |
1051 | */ | |
1052 | void check_disk_size_change(struct gendisk *disk, struct block_device *bdev) | |
1053 | { | |
1054 | loff_t disk_size, bdev_size; | |
1055 | ||
1056 | disk_size = (loff_t)get_capacity(disk) << 9; | |
1057 | bdev_size = i_size_read(bdev->bd_inode); | |
1058 | if (disk_size != bdev_size) { | |
1059 | char name[BDEVNAME_SIZE]; | |
1060 | ||
1061 | disk_name(disk, 0, name); | |
1062 | printk(KERN_INFO | |
1063 | "%s: detected capacity change from %lld to %lld\n", | |
1064 | name, bdev_size, disk_size); | |
1065 | i_size_write(bdev->bd_inode, disk_size); | |
1066 | flush_disk(bdev); | |
1067 | } | |
1068 | } | |
1069 | EXPORT_SYMBOL(check_disk_size_change); | |
1070 | ||
1071 | /** | |
1072 | * revalidate_disk - wrapper for lower-level driver's revalidate_disk call-back | |
1073 | * @disk: struct gendisk to be revalidated | |
1074 | * | |
1075 | * This routine is a wrapper for lower-level driver's revalidate_disk | |
1076 | * call-backs. It is used to do common pre and post operations needed | |
1077 | * for all revalidate_disk operations. | |
1078 | */ | |
1079 | int revalidate_disk(struct gendisk *disk) | |
1080 | { | |
1081 | struct block_device *bdev; | |
1082 | int ret = 0; | |
1083 | ||
1084 | if (disk->fops->revalidate_disk) | |
1085 | ret = disk->fops->revalidate_disk(disk); | |
1086 | ||
1087 | bdev = bdget_disk(disk, 0); | |
1088 | if (!bdev) | |
1089 | return ret; | |
1090 | ||
1091 | mutex_lock(&bdev->bd_mutex); | |
1092 | check_disk_size_change(disk, bdev); | |
1093 | mutex_unlock(&bdev->bd_mutex); | |
1094 | bdput(bdev); | |
1095 | return ret; | |
1096 | } | |
1097 | EXPORT_SYMBOL(revalidate_disk); | |
1098 | ||
1099 | /* | |
1100 | * This routine checks whether a removable media has been changed, | |
1101 | * and invalidates all buffer-cache-entries in that case. This | |
1102 | * is a relatively slow routine, so we have to try to minimize using | |
1103 | * it. Thus it is called only upon a 'mount' or 'open'. This | |
1104 | * is the best way of combining speed and utility, I think. | |
1105 | * People changing diskettes in the middle of an operation deserve | |
1106 | * to lose :-) | |
1107 | */ | |
1108 | int check_disk_change(struct block_device *bdev) | |
1109 | { | |
1110 | struct gendisk *disk = bdev->bd_disk; | |
1111 | const struct block_device_operations *bdops = disk->fops; | |
1112 | ||
1113 | if (!bdops->media_changed) | |
1114 | return 0; | |
1115 | if (!bdops->media_changed(bdev->bd_disk)) | |
1116 | return 0; | |
1117 | ||
1118 | flush_disk(bdev); | |
1119 | if (bdops->revalidate_disk) | |
1120 | bdops->revalidate_disk(bdev->bd_disk); | |
1121 | return 1; | |
1122 | } | |
1123 | ||
1124 | EXPORT_SYMBOL(check_disk_change); | |
1125 | ||
1126 | void bd_set_size(struct block_device *bdev, loff_t size) | |
1127 | { | |
1128 | unsigned bsize = bdev_logical_block_size(bdev); | |
1129 | ||
1130 | bdev->bd_inode->i_size = size; | |
1131 | while (bsize < PAGE_CACHE_SIZE) { | |
1132 | if (size & bsize) | |
1133 | break; | |
1134 | bsize <<= 1; | |
1135 | } | |
1136 | bdev->bd_block_size = bsize; | |
1137 | bdev->bd_inode->i_blkbits = blksize_bits(bsize); | |
1138 | } | |
1139 | EXPORT_SYMBOL(bd_set_size); | |
1140 | ||
1141 | static int __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part); | |
1142 | ||
1143 | /* | |
1144 | * bd_mutex locking: | |
1145 | * | |
1146 | * mutex_lock(part->bd_mutex) | |
1147 | * mutex_lock_nested(whole->bd_mutex, 1) | |
1148 | */ | |
1149 | ||
1150 | static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part) | |
1151 | { | |
1152 | struct gendisk *disk; | |
1153 | int ret; | |
1154 | int partno; | |
1155 | int perm = 0; | |
1156 | ||
1157 | if (mode & FMODE_READ) | |
1158 | perm |= MAY_READ; | |
1159 | if (mode & FMODE_WRITE) | |
1160 | perm |= MAY_WRITE; | |
1161 | /* | |
1162 | * hooks: /n/, see "layering violations". | |
1163 | */ | |
1164 | ret = devcgroup_inode_permission(bdev->bd_inode, perm); | |
1165 | if (ret != 0) { | |
1166 | bdput(bdev); | |
1167 | return ret; | |
1168 | } | |
1169 | ||
1170 | lock_kernel(); | |
1171 | restart: | |
1172 | ||
1173 | ret = -ENXIO; | |
1174 | disk = get_gendisk(bdev->bd_dev, &partno); | |
1175 | if (!disk) | |
1176 | goto out_unlock_kernel; | |
1177 | ||
1178 | mutex_lock_nested(&bdev->bd_mutex, for_part); | |
1179 | if (!bdev->bd_openers) { | |
1180 | bdev->bd_disk = disk; | |
1181 | bdev->bd_contains = bdev; | |
1182 | if (!partno) { | |
1183 | struct backing_dev_info *bdi; | |
1184 | ||
1185 | ret = -ENXIO; | |
1186 | bdev->bd_part = disk_get_part(disk, partno); | |
1187 | if (!bdev->bd_part) | |
1188 | goto out_clear; | |
1189 | ||
1190 | if (disk->fops->open) { | |
1191 | ret = disk->fops->open(bdev, mode); | |
1192 | if (ret == -ERESTARTSYS) { | |
1193 | /* Lost a race with 'disk' being | |
1194 | * deleted, try again. | |
1195 | * See md.c | |
1196 | */ | |
1197 | disk_put_part(bdev->bd_part); | |
1198 | bdev->bd_part = NULL; | |
1199 | module_put(disk->fops->owner); | |
1200 | put_disk(disk); | |
1201 | bdev->bd_disk = NULL; | |
1202 | mutex_unlock(&bdev->bd_mutex); | |
1203 | goto restart; | |
1204 | } | |
1205 | if (ret) | |
1206 | goto out_clear; | |
1207 | } | |
1208 | if (!bdev->bd_openers) { | |
1209 | bd_set_size(bdev,(loff_t)get_capacity(disk)<<9); | |
1210 | bdi = blk_get_backing_dev_info(bdev); | |
1211 | if (bdi == NULL) | |
1212 | bdi = &default_backing_dev_info; | |
1213 | bdev->bd_inode->i_data.backing_dev_info = bdi; | |
1214 | } | |
1215 | if (bdev->bd_invalidated) | |
1216 | rescan_partitions(disk, bdev); | |
1217 | } else { | |
1218 | struct block_device *whole; | |
1219 | whole = bdget_disk(disk, 0); | |
1220 | ret = -ENOMEM; | |
1221 | if (!whole) | |
1222 | goto out_clear; | |
1223 | BUG_ON(for_part); | |
1224 | ret = __blkdev_get(whole, mode, 1); | |
1225 | if (ret) | |
1226 | goto out_clear; | |
1227 | bdev->bd_contains = whole; | |
1228 | bdev->bd_inode->i_data.backing_dev_info = | |
1229 | whole->bd_inode->i_data.backing_dev_info; | |
1230 | bdev->bd_part = disk_get_part(disk, partno); | |
1231 | if (!(disk->flags & GENHD_FL_UP) || | |
1232 | !bdev->bd_part || !bdev->bd_part->nr_sects) { | |
1233 | ret = -ENXIO; | |
1234 | goto out_clear; | |
1235 | } | |
1236 | bd_set_size(bdev, (loff_t)bdev->bd_part->nr_sects << 9); | |
1237 | } | |
1238 | } else { | |
1239 | put_disk(disk); | |
1240 | module_put(disk->fops->owner); | |
1241 | disk = NULL; | |
1242 | if (bdev->bd_contains == bdev) { | |
1243 | if (bdev->bd_disk->fops->open) { | |
1244 | ret = bdev->bd_disk->fops->open(bdev, mode); | |
1245 | if (ret) | |
1246 | goto out_unlock_bdev; | |
1247 | } | |
1248 | if (bdev->bd_invalidated) | |
1249 | rescan_partitions(bdev->bd_disk, bdev); | |
1250 | } | |
1251 | } | |
1252 | bdev->bd_openers++; | |
1253 | if (for_part) | |
1254 | bdev->bd_part_count++; | |
1255 | mutex_unlock(&bdev->bd_mutex); | |
1256 | unlock_kernel(); | |
1257 | return 0; | |
1258 | ||
1259 | out_clear: | |
1260 | disk_put_part(bdev->bd_part); | |
1261 | bdev->bd_disk = NULL; | |
1262 | bdev->bd_part = NULL; | |
1263 | bdev->bd_inode->i_data.backing_dev_info = &default_backing_dev_info; | |
1264 | if (bdev != bdev->bd_contains) | |
1265 | __blkdev_put(bdev->bd_contains, mode, 1); | |
1266 | bdev->bd_contains = NULL; | |
1267 | out_unlock_bdev: | |
1268 | mutex_unlock(&bdev->bd_mutex); | |
1269 | out_unlock_kernel: | |
1270 | unlock_kernel(); | |
1271 | ||
1272 | if (disk) | |
1273 | module_put(disk->fops->owner); | |
1274 | put_disk(disk); | |
1275 | bdput(bdev); | |
1276 | ||
1277 | return ret; | |
1278 | } | |
1279 | ||
1280 | int blkdev_get(struct block_device *bdev, fmode_t mode) | |
1281 | { | |
1282 | return __blkdev_get(bdev, mode, 0); | |
1283 | } | |
1284 | EXPORT_SYMBOL(blkdev_get); | |
1285 | ||
1286 | static int blkdev_open(struct inode * inode, struct file * filp) | |
1287 | { | |
1288 | struct block_device *bdev; | |
1289 | int res; | |
1290 | ||
1291 | /* | |
1292 | * Preserve backwards compatibility and allow large file access | |
1293 | * even if userspace doesn't ask for it explicitly. Some mkfs | |
1294 | * binary needs it. We might want to drop this workaround | |
1295 | * during an unstable branch. | |
1296 | */ | |
1297 | filp->f_flags |= O_LARGEFILE; | |
1298 | ||
1299 | if (filp->f_flags & O_NDELAY) | |
1300 | filp->f_mode |= FMODE_NDELAY; | |
1301 | if (filp->f_flags & O_EXCL) | |
1302 | filp->f_mode |= FMODE_EXCL; | |
1303 | if ((filp->f_flags & O_ACCMODE) == 3) | |
1304 | filp->f_mode |= FMODE_WRITE_IOCTL; | |
1305 | ||
1306 | bdev = bd_acquire(inode); | |
1307 | if (bdev == NULL) | |
1308 | return -ENOMEM; | |
1309 | ||
1310 | filp->f_mapping = bdev->bd_inode->i_mapping; | |
1311 | ||
1312 | res = blkdev_get(bdev, filp->f_mode); | |
1313 | if (res) | |
1314 | return res; | |
1315 | ||
1316 | if (filp->f_mode & FMODE_EXCL) { | |
1317 | res = bd_claim(bdev, filp); | |
1318 | if (res) | |
1319 | goto out_blkdev_put; | |
1320 | } | |
1321 | ||
1322 | return 0; | |
1323 | ||
1324 | out_blkdev_put: | |
1325 | blkdev_put(bdev, filp->f_mode); | |
1326 | return res; | |
1327 | } | |
1328 | ||
1329 | static int __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part) | |
1330 | { | |
1331 | int ret = 0; | |
1332 | struct gendisk *disk = bdev->bd_disk; | |
1333 | struct block_device *victim = NULL; | |
1334 | ||
1335 | mutex_lock_nested(&bdev->bd_mutex, for_part); | |
1336 | lock_kernel(); | |
1337 | if (for_part) | |
1338 | bdev->bd_part_count--; | |
1339 | ||
1340 | if (!--bdev->bd_openers) { | |
1341 | sync_blockdev(bdev); | |
1342 | kill_bdev(bdev); | |
1343 | } | |
1344 | if (bdev->bd_contains == bdev) { | |
1345 | if (disk->fops->release) | |
1346 | ret = disk->fops->release(disk, mode); | |
1347 | } | |
1348 | if (!bdev->bd_openers) { | |
1349 | struct module *owner = disk->fops->owner; | |
1350 | ||
1351 | put_disk(disk); | |
1352 | module_put(owner); | |
1353 | disk_put_part(bdev->bd_part); | |
1354 | bdev->bd_part = NULL; | |
1355 | bdev->bd_disk = NULL; | |
1356 | bdev->bd_inode->i_data.backing_dev_info = &default_backing_dev_info; | |
1357 | if (bdev != bdev->bd_contains) | |
1358 | victim = bdev->bd_contains; | |
1359 | bdev->bd_contains = NULL; | |
1360 | } | |
1361 | unlock_kernel(); | |
1362 | mutex_unlock(&bdev->bd_mutex); | |
1363 | bdput(bdev); | |
1364 | if (victim) | |
1365 | __blkdev_put(victim, mode, 1); | |
1366 | return ret; | |
1367 | } | |
1368 | ||
1369 | int blkdev_put(struct block_device *bdev, fmode_t mode) | |
1370 | { | |
1371 | return __blkdev_put(bdev, mode, 0); | |
1372 | } | |
1373 | EXPORT_SYMBOL(blkdev_put); | |
1374 | ||
1375 | static int blkdev_close(struct inode * inode, struct file * filp) | |
1376 | { | |
1377 | struct block_device *bdev = I_BDEV(filp->f_mapping->host); | |
1378 | if (bdev->bd_holder == filp) | |
1379 | bd_release(bdev); | |
1380 | return blkdev_put(bdev, filp->f_mode); | |
1381 | } | |
1382 | ||
1383 | static long block_ioctl(struct file *file, unsigned cmd, unsigned long arg) | |
1384 | { | |
1385 | struct block_device *bdev = I_BDEV(file->f_mapping->host); | |
1386 | fmode_t mode = file->f_mode; | |
1387 | ||
1388 | /* | |
1389 | * O_NDELAY can be altered using fcntl(.., F_SETFL, ..), so we have | |
1390 | * to updated it before every ioctl. | |
1391 | */ | |
1392 | if (file->f_flags & O_NDELAY) | |
1393 | mode |= FMODE_NDELAY; | |
1394 | else | |
1395 | mode &= ~FMODE_NDELAY; | |
1396 | ||
1397 | return blkdev_ioctl(bdev, mode, cmd, arg); | |
1398 | } | |
1399 | ||
1400 | /* | |
1401 | * Write data to the block device. Only intended for the block device itself | |
1402 | * and the raw driver which basically is a fake block device. | |
1403 | * | |
1404 | * Does not take i_mutex for the write and thus is not for general purpose | |
1405 | * use. | |
1406 | */ | |
1407 | ssize_t blkdev_aio_write(struct kiocb *iocb, const struct iovec *iov, | |
1408 | unsigned long nr_segs, loff_t pos) | |
1409 | { | |
1410 | struct file *file = iocb->ki_filp; | |
1411 | ssize_t ret; | |
1412 | ||
1413 | BUG_ON(iocb->ki_pos != pos); | |
1414 | ||
1415 | ret = __generic_file_aio_write(iocb, iov, nr_segs, &iocb->ki_pos); | |
1416 | if (ret > 0 || ret == -EIOCBQUEUED) { | |
1417 | ssize_t err; | |
1418 | ||
1419 | err = generic_write_sync(file, pos, ret); | |
1420 | if (err < 0 && ret > 0) | |
1421 | ret = err; | |
1422 | } | |
1423 | return ret; | |
1424 | } | |
1425 | EXPORT_SYMBOL_GPL(blkdev_aio_write); | |
1426 | ||
1427 | /* | |
1428 | * Try to release a page associated with block device when the system | |
1429 | * is under memory pressure. | |
1430 | */ | |
1431 | static int blkdev_releasepage(struct page *page, gfp_t wait) | |
1432 | { | |
1433 | struct super_block *super = BDEV_I(page->mapping->host)->bdev.bd_super; | |
1434 | ||
1435 | if (super && super->s_op->bdev_try_to_free_page) | |
1436 | return super->s_op->bdev_try_to_free_page(super, page, wait); | |
1437 | ||
1438 | return try_to_free_buffers(page); | |
1439 | } | |
1440 | ||
1441 | static const struct address_space_operations def_blk_aops = { | |
1442 | .readpage = blkdev_readpage, | |
1443 | .writepage = blkdev_writepage, | |
1444 | .sync_page = block_sync_page, | |
1445 | .write_begin = blkdev_write_begin, | |
1446 | .write_end = blkdev_write_end, | |
1447 | .writepages = generic_writepages, | |
1448 | .releasepage = blkdev_releasepage, | |
1449 | .direct_IO = blkdev_direct_IO, | |
1450 | }; | |
1451 | ||
1452 | const struct file_operations def_blk_fops = { | |
1453 | .open = blkdev_open, | |
1454 | .release = blkdev_close, | |
1455 | .llseek = block_llseek, | |
1456 | .read = do_sync_read, | |
1457 | .write = do_sync_write, | |
1458 | .aio_read = generic_file_aio_read, | |
1459 | .aio_write = blkdev_aio_write, | |
1460 | .mmap = generic_file_mmap, | |
1461 | .fsync = block_fsync, | |
1462 | .unlocked_ioctl = block_ioctl, | |
1463 | #ifdef CONFIG_COMPAT | |
1464 | .compat_ioctl = compat_blkdev_ioctl, | |
1465 | #endif | |
1466 | .splice_read = generic_file_splice_read, | |
1467 | .splice_write = generic_file_splice_write, | |
1468 | }; | |
1469 | ||
1470 | int ioctl_by_bdev(struct block_device *bdev, unsigned cmd, unsigned long arg) | |
1471 | { | |
1472 | int res; | |
1473 | mm_segment_t old_fs = get_fs(); | |
1474 | set_fs(KERNEL_DS); | |
1475 | res = blkdev_ioctl(bdev, 0, cmd, arg); | |
1476 | set_fs(old_fs); | |
1477 | return res; | |
1478 | } | |
1479 | ||
1480 | EXPORT_SYMBOL(ioctl_by_bdev); | |
1481 | ||
1482 | /** | |
1483 | * lookup_bdev - lookup a struct block_device by name | |
1484 | * @pathname: special file representing the block device | |
1485 | * | |
1486 | * Get a reference to the blockdevice at @pathname in the current | |
1487 | * namespace if possible and return it. Return ERR_PTR(error) | |
1488 | * otherwise. | |
1489 | */ | |
1490 | struct block_device *lookup_bdev(const char *pathname) | |
1491 | { | |
1492 | struct block_device *bdev; | |
1493 | struct inode *inode; | |
1494 | struct path path; | |
1495 | int error; | |
1496 | ||
1497 | if (!pathname || !*pathname) | |
1498 | return ERR_PTR(-EINVAL); | |
1499 | ||
1500 | error = kern_path(pathname, LOOKUP_FOLLOW, &path); | |
1501 | if (error) | |
1502 | return ERR_PTR(error); | |
1503 | ||
1504 | inode = path.dentry->d_inode; | |
1505 | error = -ENOTBLK; | |
1506 | if (!S_ISBLK(inode->i_mode)) | |
1507 | goto fail; | |
1508 | error = -EACCES; | |
1509 | if (path.mnt->mnt_flags & MNT_NODEV) | |
1510 | goto fail; | |
1511 | error = -ENOMEM; | |
1512 | bdev = bd_acquire(inode); | |
1513 | if (!bdev) | |
1514 | goto fail; | |
1515 | out: | |
1516 | path_put(&path); | |
1517 | return bdev; | |
1518 | fail: | |
1519 | bdev = ERR_PTR(error); | |
1520 | goto out; | |
1521 | } | |
1522 | EXPORT_SYMBOL(lookup_bdev); | |
1523 | ||
1524 | /** | |
1525 | * open_bdev_exclusive - open a block device by name and set it up for use | |
1526 | * | |
1527 | * @path: special file representing the block device | |
1528 | * @mode: FMODE_... combination to pass be used | |
1529 | * @holder: owner for exclusion | |
1530 | * | |
1531 | * Open the blockdevice described by the special file at @path, claim it | |
1532 | * for the @holder. | |
1533 | */ | |
1534 | struct block_device *open_bdev_exclusive(const char *path, fmode_t mode, void *holder) | |
1535 | { | |
1536 | struct block_device *bdev; | |
1537 | int error = 0; | |
1538 | ||
1539 | bdev = lookup_bdev(path); | |
1540 | if (IS_ERR(bdev)) | |
1541 | return bdev; | |
1542 | ||
1543 | error = blkdev_get(bdev, mode); | |
1544 | if (error) | |
1545 | return ERR_PTR(error); | |
1546 | error = -EACCES; | |
1547 | if ((mode & FMODE_WRITE) && bdev_read_only(bdev)) | |
1548 | goto blkdev_put; | |
1549 | error = bd_claim(bdev, holder); | |
1550 | if (error) | |
1551 | goto blkdev_put; | |
1552 | ||
1553 | return bdev; | |
1554 | ||
1555 | blkdev_put: | |
1556 | blkdev_put(bdev, mode); | |
1557 | return ERR_PTR(error); | |
1558 | } | |
1559 | ||
1560 | EXPORT_SYMBOL(open_bdev_exclusive); | |
1561 | ||
1562 | /** | |
1563 | * close_bdev_exclusive - close a blockdevice opened by open_bdev_exclusive() | |
1564 | * | |
1565 | * @bdev: blockdevice to close | |
1566 | * @mode: mode, must match that used to open. | |
1567 | * | |
1568 | * This is the counterpart to open_bdev_exclusive(). | |
1569 | */ | |
1570 | void close_bdev_exclusive(struct block_device *bdev, fmode_t mode) | |
1571 | { | |
1572 | bd_release(bdev); | |
1573 | blkdev_put(bdev, mode); | |
1574 | } | |
1575 | ||
1576 | EXPORT_SYMBOL(close_bdev_exclusive); | |
1577 | ||
1578 | int __invalidate_device(struct block_device *bdev) | |
1579 | { | |
1580 | struct super_block *sb = get_super(bdev); | |
1581 | int res = 0; | |
1582 | ||
1583 | if (sb) { | |
1584 | /* | |
1585 | * no need to lock the super, get_super holds the | |
1586 | * read mutex so the filesystem cannot go away | |
1587 | * under us (->put_super runs with the write lock | |
1588 | * hold). | |
1589 | */ | |
1590 | shrink_dcache_sb(sb); | |
1591 | res = invalidate_inodes(sb); | |
1592 | drop_super(sb); | |
1593 | } | |
1594 | invalidate_bdev(bdev); | |
1595 | return res; | |
1596 | } | |
1597 | EXPORT_SYMBOL(__invalidate_device); |