Root/
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/device_cgroup.h> |
15 | #include <linux/highmem.h> |
16 | #include <linux/blkdev.h> |
17 | #include <linux/module.h> |
18 | #include <linux/blkpg.h> |
19 | #include <linux/buffer_head.h> |
20 | #include <linux/pagevec.h> |
21 | #include <linux/writeback.h> |
22 | #include <linux/mpage.h> |
23 | #include <linux/mount.h> |
24 | #include <linux/uio.h> |
25 | #include <linux/namei.h> |
26 | #include <linux/log2.h> |
27 | #include <linux/kmemleak.h> |
28 | #include <asm/uaccess.h> |
29 | #include "internal.h" |
30 | |
31 | struct bdev_inode { |
32 | struct block_device bdev; |
33 | struct inode vfs_inode; |
34 | }; |
35 | |
36 | static const struct address_space_operations def_blk_aops; |
37 | |
38 | static inline struct bdev_inode *BDEV_I(struct inode *inode) |
39 | { |
40 | return container_of(inode, struct bdev_inode, vfs_inode); |
41 | } |
42 | |
43 | inline struct block_device *I_BDEV(struct inode *inode) |
44 | { |
45 | return &BDEV_I(inode)->bdev; |
46 | } |
47 | |
48 | EXPORT_SYMBOL(I_BDEV); |
49 | |
50 | /* |
51 | * move the inode from it's current bdi to the a new bdi. if the inode is dirty |
52 | * we need to move it onto the dirty list of @dst so that the inode is always |
53 | * on the right list. |
54 | */ |
55 | static void bdev_inode_switch_bdi(struct inode *inode, |
56 | struct backing_dev_info *dst) |
57 | { |
58 | spin_lock(&inode_lock); |
59 | inode->i_data.backing_dev_info = dst; |
60 | if (inode->i_state & I_DIRTY) |
61 | list_move(&inode->i_wb_list, &dst->wb.b_dirty); |
62 | spin_unlock(&inode_lock); |
63 | } |
64 | |
65 | static sector_t max_block(struct block_device *bdev) |
66 | { |
67 | sector_t retval = ~((sector_t)0); |
68 | loff_t sz = i_size_read(bdev->bd_inode); |
69 | |
70 | if (sz) { |
71 | unsigned int size = block_size(bdev); |
72 | unsigned int sizebits = blksize_bits(size); |
73 | retval = (sz >> sizebits); |
74 | } |
75 | return retval; |
76 | } |
77 | |
78 | /* Kill _all_ buffers and pagecache , dirty or not.. */ |
79 | static void kill_bdev(struct block_device *bdev) |
80 | { |
81 | if (bdev->bd_inode->i_mapping->nrpages == 0) |
82 | return; |
83 | invalidate_bh_lrus(); |
84 | truncate_inode_pages(bdev->bd_inode->i_mapping, 0); |
85 | } |
86 | |
87 | int set_blocksize(struct block_device *bdev, int size) |
88 | { |
89 | /* Size must be a power of two, and between 512 and PAGE_SIZE */ |
90 | if (size > PAGE_SIZE || size < 512 || !is_power_of_2(size)) |
91 | return -EINVAL; |
92 | |
93 | /* Size cannot be smaller than the size supported by the device */ |
94 | if (size < bdev_logical_block_size(bdev)) |
95 | return -EINVAL; |
96 | |
97 | /* Don't change the size if it is same as current */ |
98 | if (bdev->bd_block_size != size) { |
99 | sync_blockdev(bdev); |
100 | bdev->bd_block_size = size; |
101 | bdev->bd_inode->i_blkbits = blksize_bits(size); |
102 | kill_bdev(bdev); |
103 | } |
104 | return 0; |
105 | } |
106 | |
107 | EXPORT_SYMBOL(set_blocksize); |
108 | |
109 | int sb_set_blocksize(struct super_block *sb, int size) |
110 | { |
111 | if (set_blocksize(sb->s_bdev, size)) |
112 | return 0; |
113 | /* If we get here, we know size is power of two |
114 | * and it's value is between 512 and PAGE_SIZE */ |
115 | sb->s_blocksize = size; |
116 | sb->s_blocksize_bits = blksize_bits(size); |
117 | return sb->s_blocksize; |
118 | } |
119 | |
120 | EXPORT_SYMBOL(sb_set_blocksize); |
121 | |
122 | int sb_min_blocksize(struct super_block *sb, int size) |
123 | { |
124 | int minsize = bdev_logical_block_size(sb->s_bdev); |
125 | if (size < minsize) |
126 | size = minsize; |
127 | return sb_set_blocksize(sb, size); |
128 | } |
129 | |
130 | EXPORT_SYMBOL(sb_min_blocksize); |
131 | |
132 | static int |
133 | blkdev_get_block(struct inode *inode, sector_t iblock, |
134 | struct buffer_head *bh, int create) |
135 | { |
136 | if (iblock >= max_block(I_BDEV(inode))) { |
137 | if (create) |
138 | return -EIO; |
139 | |
140 | /* |
141 | * for reads, we're just trying to fill a partial page. |
142 | * return a hole, they will have to call get_block again |
143 | * before they can fill it, and they will get -EIO at that |
144 | * time |
145 | */ |
146 | return 0; |
147 | } |
148 | bh->b_bdev = I_BDEV(inode); |
149 | bh->b_blocknr = iblock; |
150 | set_buffer_mapped(bh); |
151 | return 0; |
152 | } |
153 | |
154 | static int |
155 | blkdev_get_blocks(struct inode *inode, sector_t iblock, |
156 | struct buffer_head *bh, int create) |
157 | { |
158 | sector_t end_block = max_block(I_BDEV(inode)); |
159 | unsigned long max_blocks = bh->b_size >> inode->i_blkbits; |
160 | |
161 | if ((iblock + max_blocks) > end_block) { |
162 | max_blocks = end_block - iblock; |
163 | if ((long)max_blocks <= 0) { |
164 | if (create) |
165 | return -EIO; /* write fully beyond EOF */ |
166 | /* |
167 | * It is a read which is fully beyond EOF. We return |
168 | * a !buffer_mapped buffer |
169 | */ |
170 | max_blocks = 0; |
171 | } |
172 | } |
173 | |
174 | bh->b_bdev = I_BDEV(inode); |
175 | bh->b_blocknr = iblock; |
176 | bh->b_size = max_blocks << inode->i_blkbits; |
177 | if (max_blocks) |
178 | set_buffer_mapped(bh); |
179 | return 0; |
180 | } |
181 | |
182 | static ssize_t |
183 | blkdev_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov, |
184 | loff_t offset, unsigned long nr_segs) |
185 | { |
186 | struct file *file = iocb->ki_filp; |
187 | struct inode *inode = file->f_mapping->host; |
188 | |
189 | return __blockdev_direct_IO(rw, iocb, inode, I_BDEV(inode), iov, offset, |
190 | nr_segs, blkdev_get_blocks, NULL, NULL, 0); |
191 | } |
192 | |
193 | int __sync_blockdev(struct block_device *bdev, int wait) |
194 | { |
195 | if (!bdev) |
196 | return 0; |
197 | if (!wait) |
198 | return filemap_flush(bdev->bd_inode->i_mapping); |
199 | return filemap_write_and_wait(bdev->bd_inode->i_mapping); |
200 | } |
201 | |
202 | /* |
203 | * Write out and wait upon all the dirty data associated with a block |
204 | * device via its mapping. Does not take the superblock lock. |
205 | */ |
206 | int sync_blockdev(struct block_device *bdev) |
207 | { |
208 | return __sync_blockdev(bdev, 1); |
209 | } |
210 | EXPORT_SYMBOL(sync_blockdev); |
211 | |
212 | /* |
213 | * Write out and wait upon all dirty data associated with this |
214 | * device. Filesystem data as well as the underlying block |
215 | * device. Takes the superblock lock. |
216 | */ |
217 | int fsync_bdev(struct block_device *bdev) |
218 | { |
219 | struct super_block *sb = get_super(bdev); |
220 | if (sb) { |
221 | int res = sync_filesystem(sb); |
222 | drop_super(sb); |
223 | return res; |
224 | } |
225 | return sync_blockdev(bdev); |
226 | } |
227 | EXPORT_SYMBOL(fsync_bdev); |
228 | |
229 | /** |
230 | * freeze_bdev -- lock a filesystem and force it into a consistent state |
231 | * @bdev: blockdevice to lock |
232 | * |
233 | * If a superblock is found on this device, we take the s_umount semaphore |
234 | * on it to make sure nobody unmounts until the snapshot creation is done. |
235 | * The reference counter (bd_fsfreeze_count) guarantees that only the last |
236 | * unfreeze process can unfreeze the frozen filesystem actually when multiple |
237 | * freeze requests arrive simultaneously. It counts up in freeze_bdev() and |
238 | * count down in thaw_bdev(). When it becomes 0, thaw_bdev() will unfreeze |
239 | * actually. |
240 | */ |
241 | struct super_block *freeze_bdev(struct block_device *bdev) |
242 | { |
243 | struct super_block *sb; |
244 | int error = 0; |
245 | |
246 | mutex_lock(&bdev->bd_fsfreeze_mutex); |
247 | if (++bdev->bd_fsfreeze_count > 1) { |
248 | /* |
249 | * We don't even need to grab a reference - the first call |
250 | * to freeze_bdev grab an active reference and only the last |
251 | * thaw_bdev drops it. |
252 | */ |
253 | sb = get_super(bdev); |
254 | drop_super(sb); |
255 | mutex_unlock(&bdev->bd_fsfreeze_mutex); |
256 | return sb; |
257 | } |
258 | |
259 | sb = get_active_super(bdev); |
260 | if (!sb) |
261 | goto out; |
262 | error = freeze_super(sb); |
263 | if (error) { |
264 | deactivate_super(sb); |
265 | bdev->bd_fsfreeze_count--; |
266 | mutex_unlock(&bdev->bd_fsfreeze_mutex); |
267 | return ERR_PTR(error); |
268 | } |
269 | deactivate_super(sb); |
270 | out: |
271 | sync_blockdev(bdev); |
272 | mutex_unlock(&bdev->bd_fsfreeze_mutex); |
273 | return sb; /* thaw_bdev releases s->s_umount */ |
274 | } |
275 | EXPORT_SYMBOL(freeze_bdev); |
276 | |
277 | /** |
278 | * thaw_bdev -- unlock filesystem |
279 | * @bdev: blockdevice to unlock |
280 | * @sb: associated superblock |
281 | * |
282 | * Unlocks the filesystem and marks it writeable again after freeze_bdev(). |
283 | */ |
284 | int thaw_bdev(struct block_device *bdev, struct super_block *sb) |
285 | { |
286 | int error = -EINVAL; |
287 | |
288 | mutex_lock(&bdev->bd_fsfreeze_mutex); |
289 | if (!bdev->bd_fsfreeze_count) |
290 | goto out; |
291 | |
292 | error = 0; |
293 | if (--bdev->bd_fsfreeze_count > 0) |
294 | goto out; |
295 | |
296 | if (!sb) |
297 | goto out; |
298 | |
299 | error = thaw_super(sb); |
300 | if (error) { |
301 | bdev->bd_fsfreeze_count++; |
302 | mutex_unlock(&bdev->bd_fsfreeze_mutex); |
303 | return error; |
304 | } |
305 | out: |
306 | mutex_unlock(&bdev->bd_fsfreeze_mutex); |
307 | return 0; |
308 | } |
309 | EXPORT_SYMBOL(thaw_bdev); |
310 | |
311 | static int blkdev_writepage(struct page *page, struct writeback_control *wbc) |
312 | { |
313 | return block_write_full_page(page, blkdev_get_block, wbc); |
314 | } |
315 | |
316 | static int blkdev_readpage(struct file * file, struct page * page) |
317 | { |
318 | return block_read_full_page(page, blkdev_get_block); |
319 | } |
320 | |
321 | static int blkdev_write_begin(struct file *file, struct address_space *mapping, |
322 | loff_t pos, unsigned len, unsigned flags, |
323 | struct page **pagep, void **fsdata) |
324 | { |
325 | return block_write_begin(mapping, pos, len, flags, pagep, |
326 | blkdev_get_block); |
327 | } |
328 | |
329 | static int blkdev_write_end(struct file *file, struct address_space *mapping, |
330 | loff_t pos, unsigned len, unsigned copied, |
331 | struct page *page, void *fsdata) |
332 | { |
333 | int ret; |
334 | ret = block_write_end(file, mapping, pos, len, copied, page, fsdata); |
335 | |
336 | unlock_page(page); |
337 | page_cache_release(page); |
338 | |
339 | return ret; |
340 | } |
341 | |
342 | /* |
343 | * private llseek: |
344 | * for a block special file file->f_path.dentry->d_inode->i_size is zero |
345 | * so we compute the size by hand (just as in block_read/write above) |
346 | */ |
347 | static loff_t block_llseek(struct file *file, loff_t offset, int origin) |
348 | { |
349 | struct inode *bd_inode = file->f_mapping->host; |
350 | loff_t size; |
351 | loff_t retval; |
352 | |
353 | mutex_lock(&bd_inode->i_mutex); |
354 | size = i_size_read(bd_inode); |
355 | |
356 | switch (origin) { |
357 | case 2: |
358 | offset += size; |
359 | break; |
360 | case 1: |
361 | offset += file->f_pos; |
362 | } |
363 | retval = -EINVAL; |
364 | if (offset >= 0 && offset <= size) { |
365 | if (offset != file->f_pos) { |
366 | file->f_pos = offset; |
367 | } |
368 | retval = offset; |
369 | } |
370 | mutex_unlock(&bd_inode->i_mutex); |
371 | return retval; |
372 | } |
373 | |
374 | int blkdev_fsync(struct file *filp, int datasync) |
375 | { |
376 | struct inode *bd_inode = filp->f_mapping->host; |
377 | struct block_device *bdev = I_BDEV(bd_inode); |
378 | int error; |
379 | |
380 | /* |
381 | * There is no need to serialise calls to blkdev_issue_flush with |
382 | * i_mutex and doing so causes performance issues with concurrent |
383 | * O_SYNC writers to a block device. |
384 | */ |
385 | mutex_unlock(&bd_inode->i_mutex); |
386 | |
387 | error = blkdev_issue_flush(bdev, GFP_KERNEL, NULL); |
388 | if (error == -EOPNOTSUPP) |
389 | error = 0; |
390 | |
391 | mutex_lock(&bd_inode->i_mutex); |
392 | |
393 | return error; |
394 | } |
395 | EXPORT_SYMBOL(blkdev_fsync); |
396 | |
397 | /* |
398 | * pseudo-fs |
399 | */ |
400 | |
401 | static __cacheline_aligned_in_smp DEFINE_SPINLOCK(bdev_lock); |
402 | static struct kmem_cache * bdev_cachep __read_mostly; |
403 | |
404 | static struct inode *bdev_alloc_inode(struct super_block *sb) |
405 | { |
406 | struct bdev_inode *ei = kmem_cache_alloc(bdev_cachep, GFP_KERNEL); |
407 | if (!ei) |
408 | return NULL; |
409 | return &ei->vfs_inode; |
410 | } |
411 | |
412 | static void bdev_destroy_inode(struct inode *inode) |
413 | { |
414 | struct bdev_inode *bdi = BDEV_I(inode); |
415 | |
416 | kmem_cache_free(bdev_cachep, bdi); |
417 | } |
418 | |
419 | static void init_once(void *foo) |
420 | { |
421 | struct bdev_inode *ei = (struct bdev_inode *) foo; |
422 | struct block_device *bdev = &ei->bdev; |
423 | |
424 | memset(bdev, 0, sizeof(*bdev)); |
425 | mutex_init(&bdev->bd_mutex); |
426 | INIT_LIST_HEAD(&bdev->bd_inodes); |
427 | INIT_LIST_HEAD(&bdev->bd_list); |
428 | #ifdef CONFIG_SYSFS |
429 | INIT_LIST_HEAD(&bdev->bd_holder_list); |
430 | #endif |
431 | inode_init_once(&ei->vfs_inode); |
432 | /* Initialize mutex for freeze. */ |
433 | mutex_init(&bdev->bd_fsfreeze_mutex); |
434 | } |
435 | |
436 | static inline void __bd_forget(struct inode *inode) |
437 | { |
438 | list_del_init(&inode->i_devices); |
439 | inode->i_bdev = NULL; |
440 | inode->i_mapping = &inode->i_data; |
441 | } |
442 | |
443 | static void bdev_evict_inode(struct inode *inode) |
444 | { |
445 | struct block_device *bdev = &BDEV_I(inode)->bdev; |
446 | struct list_head *p; |
447 | truncate_inode_pages(&inode->i_data, 0); |
448 | invalidate_inode_buffers(inode); /* is it needed here? */ |
449 | end_writeback(inode); |
450 | spin_lock(&bdev_lock); |
451 | while ( (p = bdev->bd_inodes.next) != &bdev->bd_inodes ) { |
452 | __bd_forget(list_entry(p, struct inode, i_devices)); |
453 | } |
454 | list_del_init(&bdev->bd_list); |
455 | spin_unlock(&bdev_lock); |
456 | } |
457 | |
458 | static const struct super_operations bdev_sops = { |
459 | .statfs = simple_statfs, |
460 | .alloc_inode = bdev_alloc_inode, |
461 | .destroy_inode = bdev_destroy_inode, |
462 | .drop_inode = generic_delete_inode, |
463 | .evict_inode = bdev_evict_inode, |
464 | }; |
465 | |
466 | static struct dentry *bd_mount(struct file_system_type *fs_type, |
467 | int flags, const char *dev_name, void *data) |
468 | { |
469 | return mount_pseudo(fs_type, "bdev:", &bdev_sops, 0x62646576); |
470 | } |
471 | |
472 | static struct file_system_type bd_type = { |
473 | .name = "bdev", |
474 | .mount = bd_mount, |
475 | .kill_sb = kill_anon_super, |
476 | }; |
477 | |
478 | struct super_block *blockdev_superblock __read_mostly; |
479 | |
480 | void __init bdev_cache_init(void) |
481 | { |
482 | int err; |
483 | struct vfsmount *bd_mnt; |
484 | |
485 | bdev_cachep = kmem_cache_create("bdev_cache", sizeof(struct bdev_inode), |
486 | 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT| |
487 | SLAB_MEM_SPREAD|SLAB_PANIC), |
488 | init_once); |
489 | err = register_filesystem(&bd_type); |
490 | if (err) |
491 | panic("Cannot register bdev pseudo-fs"); |
492 | bd_mnt = kern_mount(&bd_type); |
493 | if (IS_ERR(bd_mnt)) |
494 | panic("Cannot create bdev pseudo-fs"); |
495 | /* |
496 | * This vfsmount structure is only used to obtain the |
497 | * blockdev_superblock, so tell kmemleak not to report it. |
498 | */ |
499 | kmemleak_not_leak(bd_mnt); |
500 | blockdev_superblock = bd_mnt->mnt_sb; /* For writeback */ |
501 | } |
502 | |
503 | /* |
504 | * Most likely _very_ bad one - but then it's hardly critical for small |
505 | * /dev and can be fixed when somebody will need really large one. |
506 | * Keep in mind that it will be fed through icache hash function too. |
507 | */ |
508 | static inline unsigned long hash(dev_t dev) |
509 | { |
510 | return MAJOR(dev)+MINOR(dev); |
511 | } |
512 | |
513 | static int bdev_test(struct inode *inode, void *data) |
514 | { |
515 | return BDEV_I(inode)->bdev.bd_dev == *(dev_t *)data; |
516 | } |
517 | |
518 | static int bdev_set(struct inode *inode, void *data) |
519 | { |
520 | BDEV_I(inode)->bdev.bd_dev = *(dev_t *)data; |
521 | return 0; |
522 | } |
523 | |
524 | static LIST_HEAD(all_bdevs); |
525 | |
526 | struct block_device *bdget(dev_t dev) |
527 | { |
528 | struct block_device *bdev; |
529 | struct inode *inode; |
530 | |
531 | inode = iget5_locked(blockdev_superblock, hash(dev), |
532 | bdev_test, bdev_set, &dev); |
533 | |
534 | if (!inode) |
535 | return NULL; |
536 | |
537 | bdev = &BDEV_I(inode)->bdev; |
538 | |
539 | if (inode->i_state & I_NEW) { |
540 | bdev->bd_contains = NULL; |
541 | bdev->bd_inode = inode; |
542 | bdev->bd_block_size = (1 << inode->i_blkbits); |
543 | bdev->bd_part_count = 0; |
544 | bdev->bd_invalidated = 0; |
545 | inode->i_mode = S_IFBLK; |
546 | inode->i_rdev = dev; |
547 | inode->i_bdev = bdev; |
548 | inode->i_data.a_ops = &def_blk_aops; |
549 | mapping_set_gfp_mask(&inode->i_data, GFP_USER); |
550 | inode->i_data.backing_dev_info = &default_backing_dev_info; |
551 | spin_lock(&bdev_lock); |
552 | list_add(&bdev->bd_list, &all_bdevs); |
553 | spin_unlock(&bdev_lock); |
554 | unlock_new_inode(inode); |
555 | } |
556 | return bdev; |
557 | } |
558 | |
559 | EXPORT_SYMBOL(bdget); |
560 | |
561 | /** |
562 | * bdgrab -- Grab a reference to an already referenced block device |
563 | * @bdev: Block device to grab a reference to. |
564 | */ |
565 | struct block_device *bdgrab(struct block_device *bdev) |
566 | { |
567 | ihold(bdev->bd_inode); |
568 | return bdev; |
569 | } |
570 | |
571 | long nr_blockdev_pages(void) |
572 | { |
573 | struct block_device *bdev; |
574 | long ret = 0; |
575 | spin_lock(&bdev_lock); |
576 | list_for_each_entry(bdev, &all_bdevs, bd_list) { |
577 | ret += bdev->bd_inode->i_mapping->nrpages; |
578 | } |
579 | spin_unlock(&bdev_lock); |
580 | return ret; |
581 | } |
582 | |
583 | void bdput(struct block_device *bdev) |
584 | { |
585 | iput(bdev->bd_inode); |
586 | } |
587 | |
588 | EXPORT_SYMBOL(bdput); |
589 | |
590 | static struct block_device *bd_acquire(struct inode *inode) |
591 | { |
592 | struct block_device *bdev; |
593 | |
594 | spin_lock(&bdev_lock); |
595 | bdev = inode->i_bdev; |
596 | if (bdev) { |
597 | ihold(bdev->bd_inode); |
598 | spin_unlock(&bdev_lock); |
599 | return bdev; |
600 | } |
601 | spin_unlock(&bdev_lock); |
602 | |
603 | bdev = bdget(inode->i_rdev); |
604 | if (bdev) { |
605 | spin_lock(&bdev_lock); |
606 | if (!inode->i_bdev) { |
607 | /* |
608 | * We take an additional reference to bd_inode, |
609 | * and it's released in clear_inode() of inode. |
610 | * So, we can access it via ->i_mapping always |
611 | * without igrab(). |
612 | */ |
613 | ihold(bdev->bd_inode); |
614 | inode->i_bdev = bdev; |
615 | inode->i_mapping = bdev->bd_inode->i_mapping; |
616 | list_add(&inode->i_devices, &bdev->bd_inodes); |
617 | } |
618 | spin_unlock(&bdev_lock); |
619 | } |
620 | return bdev; |
621 | } |
622 | |
623 | /* Call when you free inode */ |
624 | |
625 | void bd_forget(struct inode *inode) |
626 | { |
627 | struct block_device *bdev = NULL; |
628 | |
629 | spin_lock(&bdev_lock); |
630 | if (inode->i_bdev) { |
631 | if (!sb_is_blkdev_sb(inode->i_sb)) |
632 | bdev = inode->i_bdev; |
633 | __bd_forget(inode); |
634 | } |
635 | spin_unlock(&bdev_lock); |
636 | |
637 | if (bdev) |
638 | iput(bdev->bd_inode); |
639 | } |
640 | |
641 | /** |
642 | * bd_may_claim - test whether a block device can be claimed |
643 | * @bdev: block device of interest |
644 | * @whole: whole block device containing @bdev, may equal @bdev |
645 | * @holder: holder trying to claim @bdev |
646 | * |
647 | * Test whther @bdev can be claimed by @holder. |
648 | * |
649 | * CONTEXT: |
650 | * spin_lock(&bdev_lock). |
651 | * |
652 | * RETURNS: |
653 | * %true if @bdev can be claimed, %false otherwise. |
654 | */ |
655 | static bool bd_may_claim(struct block_device *bdev, struct block_device *whole, |
656 | void *holder) |
657 | { |
658 | if (bdev->bd_holder == holder) |
659 | return true; /* already a holder */ |
660 | else if (bdev->bd_holder != NULL) |
661 | return false; /* held by someone else */ |
662 | else if (bdev->bd_contains == bdev) |
663 | return true; /* is a whole device which isn't held */ |
664 | |
665 | else if (whole->bd_holder == bd_claim) |
666 | return true; /* is a partition of a device that is being partitioned */ |
667 | else if (whole->bd_holder != NULL) |
668 | return false; /* is a partition of a held device */ |
669 | else |
670 | return true; /* is a partition of an un-held device */ |
671 | } |
672 | |
673 | /** |
674 | * bd_prepare_to_claim - prepare to claim a block device |
675 | * @bdev: block device of interest |
676 | * @whole: the whole device containing @bdev, may equal @bdev |
677 | * @holder: holder trying to claim @bdev |
678 | * |
679 | * Prepare to claim @bdev. This function fails if @bdev is already |
680 | * claimed by another holder and waits if another claiming is in |
681 | * progress. This function doesn't actually claim. On successful |
682 | * return, the caller has ownership of bd_claiming and bd_holder[s]. |
683 | * |
684 | * CONTEXT: |
685 | * spin_lock(&bdev_lock). Might release bdev_lock, sleep and regrab |
686 | * it multiple times. |
687 | * |
688 | * RETURNS: |
689 | * 0 if @bdev can be claimed, -EBUSY otherwise. |
690 | */ |
691 | static int bd_prepare_to_claim(struct block_device *bdev, |
692 | struct block_device *whole, void *holder) |
693 | { |
694 | retry: |
695 | /* if someone else claimed, fail */ |
696 | if (!bd_may_claim(bdev, whole, holder)) |
697 | return -EBUSY; |
698 | |
699 | /* if claiming is already in progress, wait for it to finish */ |
700 | if (whole->bd_claiming) { |
701 | wait_queue_head_t *wq = bit_waitqueue(&whole->bd_claiming, 0); |
702 | DEFINE_WAIT(wait); |
703 | |
704 | prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE); |
705 | spin_unlock(&bdev_lock); |
706 | schedule(); |
707 | finish_wait(wq, &wait); |
708 | spin_lock(&bdev_lock); |
709 | goto retry; |
710 | } |
711 | |
712 | /* yay, all mine */ |
713 | return 0; |
714 | } |
715 | |
716 | /** |
717 | * bd_start_claiming - start claiming a block device |
718 | * @bdev: block device of interest |
719 | * @holder: holder trying to claim @bdev |
720 | * |
721 | * @bdev is about to be opened exclusively. Check @bdev can be opened |
722 | * exclusively and mark that an exclusive open is in progress. Each |
723 | * successful call to this function must be matched with a call to |
724 | * either bd_finish_claiming() or bd_abort_claiming() (which do not |
725 | * fail). |
726 | * |
727 | * This function is used to gain exclusive access to the block device |
728 | * without actually causing other exclusive open attempts to fail. It |
729 | * should be used when the open sequence itself requires exclusive |
730 | * access but may subsequently fail. |
731 | * |
732 | * CONTEXT: |
733 | * Might sleep. |
734 | * |
735 | * RETURNS: |
736 | * Pointer to the block device containing @bdev on success, ERR_PTR() |
737 | * value on failure. |
738 | */ |
739 | static struct block_device *bd_start_claiming(struct block_device *bdev, |
740 | void *holder) |
741 | { |
742 | struct gendisk *disk; |
743 | struct block_device *whole; |
744 | int partno, err; |
745 | |
746 | might_sleep(); |
747 | |
748 | /* |
749 | * @bdev might not have been initialized properly yet, look up |
750 | * and grab the outer block device the hard way. |
751 | */ |
752 | disk = get_gendisk(bdev->bd_dev, &partno); |
753 | if (!disk) |
754 | return ERR_PTR(-ENXIO); |
755 | |
756 | whole = bdget_disk(disk, 0); |
757 | module_put(disk->fops->owner); |
758 | put_disk(disk); |
759 | if (!whole) |
760 | return ERR_PTR(-ENOMEM); |
761 | |
762 | /* prepare to claim, if successful, mark claiming in progress */ |
763 | spin_lock(&bdev_lock); |
764 | |
765 | err = bd_prepare_to_claim(bdev, whole, holder); |
766 | if (err == 0) { |
767 | whole->bd_claiming = holder; |
768 | spin_unlock(&bdev_lock); |
769 | return whole; |
770 | } else { |
771 | spin_unlock(&bdev_lock); |
772 | bdput(whole); |
773 | return ERR_PTR(err); |
774 | } |
775 | } |
776 | |
777 | /* releases bdev_lock */ |
778 | static void __bd_abort_claiming(struct block_device *whole, void *holder) |
779 | { |
780 | BUG_ON(whole->bd_claiming != holder); |
781 | whole->bd_claiming = NULL; |
782 | wake_up_bit(&whole->bd_claiming, 0); |
783 | |
784 | spin_unlock(&bdev_lock); |
785 | bdput(whole); |
786 | } |
787 | |
788 | /** |
789 | * bd_abort_claiming - abort claiming a block device |
790 | * @whole: whole block device returned by bd_start_claiming() |
791 | * @holder: holder trying to claim @bdev |
792 | * |
793 | * Abort a claiming block started by bd_start_claiming(). Note that |
794 | * @whole is not the block device to be claimed but the whole device |
795 | * returned by bd_start_claiming(). |
796 | * |
797 | * CONTEXT: |
798 | * Grabs and releases bdev_lock. |
799 | */ |
800 | static void bd_abort_claiming(struct block_device *whole, void *holder) |
801 | { |
802 | spin_lock(&bdev_lock); |
803 | __bd_abort_claiming(whole, holder); /* releases bdev_lock */ |
804 | } |
805 | |
806 | /* increment holders when we have a legitimate claim. requires bdev_lock */ |
807 | static void __bd_claim(struct block_device *bdev, struct block_device *whole, |
808 | void *holder) |
809 | { |
810 | /* note that for a whole device bd_holders |
811 | * will be incremented twice, and bd_holder will |
812 | * be set to bd_claim before being set to holder |
813 | */ |
814 | whole->bd_holders++; |
815 | whole->bd_holder = bd_claim; |
816 | bdev->bd_holders++; |
817 | bdev->bd_holder = holder; |
818 | } |
819 | |
820 | /** |
821 | * bd_finish_claiming - finish claiming a block device |
822 | * @bdev: block device of interest (passed to bd_start_claiming()) |
823 | * @whole: whole block device returned by bd_start_claiming() |
824 | * @holder: holder trying to claim @bdev |
825 | * |
826 | * Finish a claiming block started by bd_start_claiming(). |
827 | * |
828 | * CONTEXT: |
829 | * Grabs and releases bdev_lock. |
830 | */ |
831 | static void bd_finish_claiming(struct block_device *bdev, |
832 | struct block_device *whole, void *holder) |
833 | { |
834 | spin_lock(&bdev_lock); |
835 | BUG_ON(!bd_may_claim(bdev, whole, holder)); |
836 | __bd_claim(bdev, whole, holder); |
837 | __bd_abort_claiming(whole, holder); /* not actually an abort */ |
838 | } |
839 | |
840 | /** |
841 | * bd_claim - claim a block device |
842 | * @bdev: block device to claim |
843 | * @holder: holder trying to claim @bdev |
844 | * |
845 | * Try to claim @bdev which must have been opened successfully. |
846 | * |
847 | * CONTEXT: |
848 | * Might sleep. |
849 | * |
850 | * RETURNS: |
851 | * 0 if successful, -EBUSY if @bdev is already claimed. |
852 | */ |
853 | int bd_claim(struct block_device *bdev, void *holder) |
854 | { |
855 | struct block_device *whole = bdev->bd_contains; |
856 | int res; |
857 | |
858 | might_sleep(); |
859 | |
860 | spin_lock(&bdev_lock); |
861 | res = bd_prepare_to_claim(bdev, whole, holder); |
862 | if (res == 0) |
863 | __bd_claim(bdev, whole, holder); |
864 | spin_unlock(&bdev_lock); |
865 | |
866 | return res; |
867 | } |
868 | EXPORT_SYMBOL(bd_claim); |
869 | |
870 | void bd_release(struct block_device *bdev) |
871 | { |
872 | spin_lock(&bdev_lock); |
873 | if (!--bdev->bd_contains->bd_holders) |
874 | bdev->bd_contains->bd_holder = NULL; |
875 | if (!--bdev->bd_holders) |
876 | bdev->bd_holder = NULL; |
877 | spin_unlock(&bdev_lock); |
878 | } |
879 | |
880 | EXPORT_SYMBOL(bd_release); |
881 | |
882 | #ifdef CONFIG_SYSFS |
883 | /* |
884 | * Functions for bd_claim_by_kobject / bd_release_from_kobject |
885 | * |
886 | * If a kobject is passed to bd_claim_by_kobject() |
887 | * and the kobject has a parent directory, |
888 | * following symlinks are created: |
889 | * o from the kobject to the claimed bdev |
890 | * o from "holders" directory of the bdev to the parent of the kobject |
891 | * bd_release_from_kobject() removes these symlinks. |
892 | * |
893 | * Example: |
894 | * If /dev/dm-0 maps to /dev/sda, kobject corresponding to |
895 | * /sys/block/dm-0/slaves is passed to bd_claim_by_kobject(), then: |
896 | * /sys/block/dm-0/slaves/sda --> /sys/block/sda |
897 | * /sys/block/sda/holders/dm-0 --> /sys/block/dm-0 |
898 | */ |
899 | |
900 | static int add_symlink(struct kobject *from, struct kobject *to) |
901 | { |
902 | if (!from || !to) |
903 | return 0; |
904 | return sysfs_create_link(from, to, kobject_name(to)); |
905 | } |
906 | |
907 | static void del_symlink(struct kobject *from, struct kobject *to) |
908 | { |
909 | if (!from || !to) |
910 | return; |
911 | sysfs_remove_link(from, kobject_name(to)); |
912 | } |
913 | |
914 | /* |
915 | * 'struct bd_holder' contains pointers to kobjects symlinked by |
916 | * bd_claim_by_kobject. |
917 | * It's connected to bd_holder_list which is protected by bdev->bd_sem. |
918 | */ |
919 | struct bd_holder { |
920 | struct list_head list; /* chain of holders of the bdev */ |
921 | int count; /* references from the holder */ |
922 | struct kobject *sdir; /* holder object, e.g. "/block/dm-0/slaves" */ |
923 | struct kobject *hdev; /* e.g. "/block/dm-0" */ |
924 | struct kobject *hdir; /* e.g. "/block/sda/holders" */ |
925 | struct kobject *sdev; /* e.g. "/block/sda" */ |
926 | }; |
927 | |
928 | /* |
929 | * Get references of related kobjects at once. |
930 | * Returns 1 on success. 0 on failure. |
931 | * |
932 | * Should call bd_holder_release_dirs() after successful use. |
933 | */ |
934 | static int bd_holder_grab_dirs(struct block_device *bdev, |
935 | struct bd_holder *bo) |
936 | { |
937 | if (!bdev || !bo) |
938 | return 0; |
939 | |
940 | bo->sdir = kobject_get(bo->sdir); |
941 | if (!bo->sdir) |
942 | return 0; |
943 | |
944 | bo->hdev = kobject_get(bo->sdir->parent); |
945 | if (!bo->hdev) |
946 | goto fail_put_sdir; |
947 | |
948 | bo->sdev = kobject_get(&part_to_dev(bdev->bd_part)->kobj); |
949 | if (!bo->sdev) |
950 | goto fail_put_hdev; |
951 | |
952 | bo->hdir = kobject_get(bdev->bd_part->holder_dir); |
953 | if (!bo->hdir) |
954 | goto fail_put_sdev; |
955 | |
956 | return 1; |
957 | |
958 | fail_put_sdev: |
959 | kobject_put(bo->sdev); |
960 | fail_put_hdev: |
961 | kobject_put(bo->hdev); |
962 | fail_put_sdir: |
963 | kobject_put(bo->sdir); |
964 | |
965 | return 0; |
966 | } |
967 | |
968 | /* Put references of related kobjects at once. */ |
969 | static void bd_holder_release_dirs(struct bd_holder *bo) |
970 | { |
971 | kobject_put(bo->hdir); |
972 | kobject_put(bo->sdev); |
973 | kobject_put(bo->hdev); |
974 | kobject_put(bo->sdir); |
975 | } |
976 | |
977 | static struct bd_holder *alloc_bd_holder(struct kobject *kobj) |
978 | { |
979 | struct bd_holder *bo; |
980 | |
981 | bo = kzalloc(sizeof(*bo), GFP_KERNEL); |
982 | if (!bo) |
983 | return NULL; |
984 | |
985 | bo->count = 1; |
986 | bo->sdir = kobj; |
987 | |
988 | return bo; |
989 | } |
990 | |
991 | static void free_bd_holder(struct bd_holder *bo) |
992 | { |
993 | kfree(bo); |
994 | } |
995 | |
996 | /** |
997 | * find_bd_holder - find matching struct bd_holder from the block device |
998 | * |
999 | * @bdev: struct block device to be searched |
1000 | * @bo: target struct bd_holder |
1001 | * |
1002 | * Returns matching entry with @bo in @bdev->bd_holder_list. |
1003 | * If found, increment the reference count and return the pointer. |
1004 | * If not found, returns NULL. |
1005 | */ |
1006 | static struct bd_holder *find_bd_holder(struct block_device *bdev, |
1007 | struct bd_holder *bo) |
1008 | { |
1009 | struct bd_holder *tmp; |
1010 | |
1011 | list_for_each_entry(tmp, &bdev->bd_holder_list, list) |
1012 | if (tmp->sdir == bo->sdir) { |
1013 | tmp->count++; |
1014 | return tmp; |
1015 | } |
1016 | |
1017 | return NULL; |
1018 | } |
1019 | |
1020 | /** |
1021 | * add_bd_holder - create sysfs symlinks for bd_claim() relationship |
1022 | * |
1023 | * @bdev: block device to be bd_claimed |
1024 | * @bo: preallocated and initialized by alloc_bd_holder() |
1025 | * |
1026 | * Add @bo to @bdev->bd_holder_list, create symlinks. |
1027 | * |
1028 | * Returns 0 if symlinks are created. |
1029 | * Returns -ve if something fails. |
1030 | */ |
1031 | static int add_bd_holder(struct block_device *bdev, struct bd_holder *bo) |
1032 | { |
1033 | int err; |
1034 | |
1035 | if (!bo) |
1036 | return -EINVAL; |
1037 | |
1038 | if (!bd_holder_grab_dirs(bdev, bo)) |
1039 | return -EBUSY; |
1040 | |
1041 | err = add_symlink(bo->sdir, bo->sdev); |
1042 | if (err) |
1043 | return err; |
1044 | |
1045 | err = add_symlink(bo->hdir, bo->hdev); |
1046 | if (err) { |
1047 | del_symlink(bo->sdir, bo->sdev); |
1048 | return err; |
1049 | } |
1050 | |
1051 | list_add_tail(&bo->list, &bdev->bd_holder_list); |
1052 | return 0; |
1053 | } |
1054 | |
1055 | /** |
1056 | * del_bd_holder - delete sysfs symlinks for bd_claim() relationship |
1057 | * |
1058 | * @bdev: block device to be bd_claimed |
1059 | * @kobj: holder's kobject |
1060 | * |
1061 | * If there is matching entry with @kobj in @bdev->bd_holder_list |
1062 | * and no other bd_claim() from the same kobject, |
1063 | * remove the struct bd_holder from the list, delete symlinks for it. |
1064 | * |
1065 | * Returns a pointer to the struct bd_holder when it's removed from the list |
1066 | * and ready to be freed. |
1067 | * Returns NULL if matching claim isn't found or there is other bd_claim() |
1068 | * by the same kobject. |
1069 | */ |
1070 | static struct bd_holder *del_bd_holder(struct block_device *bdev, |
1071 | struct kobject *kobj) |
1072 | { |
1073 | struct bd_holder *bo; |
1074 | |
1075 | list_for_each_entry(bo, &bdev->bd_holder_list, list) { |
1076 | if (bo->sdir == kobj) { |
1077 | bo->count--; |
1078 | BUG_ON(bo->count < 0); |
1079 | if (!bo->count) { |
1080 | list_del(&bo->list); |
1081 | del_symlink(bo->sdir, bo->sdev); |
1082 | del_symlink(bo->hdir, bo->hdev); |
1083 | bd_holder_release_dirs(bo); |
1084 | return bo; |
1085 | } |
1086 | break; |
1087 | } |
1088 | } |
1089 | |
1090 | return NULL; |
1091 | } |
1092 | |
1093 | /** |
1094 | * bd_claim_by_kobject - bd_claim() with additional kobject signature |
1095 | * |
1096 | * @bdev: block device to be claimed |
1097 | * @holder: holder's signature |
1098 | * @kobj: holder's kobject |
1099 | * |
1100 | * Do bd_claim() and if it succeeds, create sysfs symlinks between |
1101 | * the bdev and the holder's kobject. |
1102 | * Use bd_release_from_kobject() when relesing the claimed bdev. |
1103 | * |
1104 | * Returns 0 on success. (same as bd_claim()) |
1105 | * Returns errno on failure. |
1106 | */ |
1107 | static int bd_claim_by_kobject(struct block_device *bdev, void *holder, |
1108 | struct kobject *kobj) |
1109 | { |
1110 | int err; |
1111 | struct bd_holder *bo, *found; |
1112 | |
1113 | if (!kobj) |
1114 | return -EINVAL; |
1115 | |
1116 | bo = alloc_bd_holder(kobj); |
1117 | if (!bo) |
1118 | return -ENOMEM; |
1119 | |
1120 | mutex_lock(&bdev->bd_mutex); |
1121 | |
1122 | err = bd_claim(bdev, holder); |
1123 | if (err) |
1124 | goto fail; |
1125 | |
1126 | found = find_bd_holder(bdev, bo); |
1127 | if (found) |
1128 | goto fail; |
1129 | |
1130 | err = add_bd_holder(bdev, bo); |
1131 | if (err) |
1132 | bd_release(bdev); |
1133 | else |
1134 | bo = NULL; |
1135 | fail: |
1136 | mutex_unlock(&bdev->bd_mutex); |
1137 | free_bd_holder(bo); |
1138 | return err; |
1139 | } |
1140 | |
1141 | /** |
1142 | * bd_release_from_kobject - bd_release() with additional kobject signature |
1143 | * |
1144 | * @bdev: block device to be released |
1145 | * @kobj: holder's kobject |
1146 | * |
1147 | * Do bd_release() and remove sysfs symlinks created by bd_claim_by_kobject(). |
1148 | */ |
1149 | static void bd_release_from_kobject(struct block_device *bdev, |
1150 | struct kobject *kobj) |
1151 | { |
1152 | if (!kobj) |
1153 | return; |
1154 | |
1155 | mutex_lock(&bdev->bd_mutex); |
1156 | bd_release(bdev); |
1157 | free_bd_holder(del_bd_holder(bdev, kobj)); |
1158 | mutex_unlock(&bdev->bd_mutex); |
1159 | } |
1160 | |
1161 | /** |
1162 | * bd_claim_by_disk - wrapper function for bd_claim_by_kobject() |
1163 | * |
1164 | * @bdev: block device to be claimed |
1165 | * @holder: holder's signature |
1166 | * @disk: holder's gendisk |
1167 | * |
1168 | * Call bd_claim_by_kobject() with getting @disk->slave_dir. |
1169 | */ |
1170 | int bd_claim_by_disk(struct block_device *bdev, void *holder, |
1171 | struct gendisk *disk) |
1172 | { |
1173 | return bd_claim_by_kobject(bdev, holder, kobject_get(disk->slave_dir)); |
1174 | } |
1175 | EXPORT_SYMBOL_GPL(bd_claim_by_disk); |
1176 | |
1177 | /** |
1178 | * bd_release_from_disk - wrapper function for bd_release_from_kobject() |
1179 | * |
1180 | * @bdev: block device to be claimed |
1181 | * @disk: holder's gendisk |
1182 | * |
1183 | * Call bd_release_from_kobject() and put @disk->slave_dir. |
1184 | */ |
1185 | void bd_release_from_disk(struct block_device *bdev, struct gendisk *disk) |
1186 | { |
1187 | bd_release_from_kobject(bdev, disk->slave_dir); |
1188 | kobject_put(disk->slave_dir); |
1189 | } |
1190 | EXPORT_SYMBOL_GPL(bd_release_from_disk); |
1191 | #endif |
1192 | |
1193 | /* |
1194 | * Tries to open block device by device number. Use it ONLY if you |
1195 | * really do not have anything better - i.e. when you are behind a |
1196 | * truly sucky interface and all you are given is a device number. _Never_ |
1197 | * to be used for internal purposes. If you ever need it - reconsider |
1198 | * your API. |
1199 | */ |
1200 | struct block_device *open_by_devnum(dev_t dev, fmode_t mode) |
1201 | { |
1202 | struct block_device *bdev = bdget(dev); |
1203 | int err = -ENOMEM; |
1204 | if (bdev) |
1205 | err = blkdev_get(bdev, mode); |
1206 | return err ? ERR_PTR(err) : bdev; |
1207 | } |
1208 | |
1209 | EXPORT_SYMBOL(open_by_devnum); |
1210 | |
1211 | /** |
1212 | * flush_disk - invalidates all buffer-cache entries on a disk |
1213 | * |
1214 | * @bdev: struct block device to be flushed |
1215 | * |
1216 | * Invalidates all buffer-cache entries on a disk. It should be called |
1217 | * when a disk has been changed -- either by a media change or online |
1218 | * resize. |
1219 | */ |
1220 | static void flush_disk(struct block_device *bdev) |
1221 | { |
1222 | if (__invalidate_device(bdev)) { |
1223 | char name[BDEVNAME_SIZE] = ""; |
1224 | |
1225 | if (bdev->bd_disk) |
1226 | disk_name(bdev->bd_disk, 0, name); |
1227 | printk(KERN_WARNING "VFS: busy inodes on changed media or " |
1228 | "resized disk %s\n", name); |
1229 | } |
1230 | |
1231 | if (!bdev->bd_disk) |
1232 | return; |
1233 | if (disk_partitionable(bdev->bd_disk)) |
1234 | bdev->bd_invalidated = 1; |
1235 | } |
1236 | |
1237 | /** |
1238 | * check_disk_size_change - checks for disk size change and adjusts bdev size. |
1239 | * @disk: struct gendisk to check |
1240 | * @bdev: struct bdev to adjust. |
1241 | * |
1242 | * This routine checks to see if the bdev size does not match the disk size |
1243 | * and adjusts it if it differs. |
1244 | */ |
1245 | void check_disk_size_change(struct gendisk *disk, struct block_device *bdev) |
1246 | { |
1247 | loff_t disk_size, bdev_size; |
1248 | |
1249 | disk_size = (loff_t)get_capacity(disk) << 9; |
1250 | bdev_size = i_size_read(bdev->bd_inode); |
1251 | if (disk_size != bdev_size) { |
1252 | char name[BDEVNAME_SIZE]; |
1253 | |
1254 | disk_name(disk, 0, name); |
1255 | printk(KERN_INFO |
1256 | "%s: detected capacity change from %lld to %lld\n", |
1257 | name, bdev_size, disk_size); |
1258 | i_size_write(bdev->bd_inode, disk_size); |
1259 | flush_disk(bdev); |
1260 | } |
1261 | } |
1262 | EXPORT_SYMBOL(check_disk_size_change); |
1263 | |
1264 | /** |
1265 | * revalidate_disk - wrapper for lower-level driver's revalidate_disk call-back |
1266 | * @disk: struct gendisk to be revalidated |
1267 | * |
1268 | * This routine is a wrapper for lower-level driver's revalidate_disk |
1269 | * call-backs. It is used to do common pre and post operations needed |
1270 | * for all revalidate_disk operations. |
1271 | */ |
1272 | int revalidate_disk(struct gendisk *disk) |
1273 | { |
1274 | struct block_device *bdev; |
1275 | int ret = 0; |
1276 | |
1277 | if (disk->fops->revalidate_disk) |
1278 | ret = disk->fops->revalidate_disk(disk); |
1279 | |
1280 | bdev = bdget_disk(disk, 0); |
1281 | if (!bdev) |
1282 | return ret; |
1283 | |
1284 | mutex_lock(&bdev->bd_mutex); |
1285 | check_disk_size_change(disk, bdev); |
1286 | mutex_unlock(&bdev->bd_mutex); |
1287 | bdput(bdev); |
1288 | return ret; |
1289 | } |
1290 | EXPORT_SYMBOL(revalidate_disk); |
1291 | |
1292 | /* |
1293 | * This routine checks whether a removable media has been changed, |
1294 | * and invalidates all buffer-cache-entries in that case. This |
1295 | * is a relatively slow routine, so we have to try to minimize using |
1296 | * it. Thus it is called only upon a 'mount' or 'open'. This |
1297 | * is the best way of combining speed and utility, I think. |
1298 | * People changing diskettes in the middle of an operation deserve |
1299 | * to lose :-) |
1300 | */ |
1301 | int check_disk_change(struct block_device *bdev) |
1302 | { |
1303 | struct gendisk *disk = bdev->bd_disk; |
1304 | const struct block_device_operations *bdops = disk->fops; |
1305 | |
1306 | if (!bdops->media_changed) |
1307 | return 0; |
1308 | if (!bdops->media_changed(bdev->bd_disk)) |
1309 | return 0; |
1310 | |
1311 | flush_disk(bdev); |
1312 | if (bdops->revalidate_disk) |
1313 | bdops->revalidate_disk(bdev->bd_disk); |
1314 | return 1; |
1315 | } |
1316 | |
1317 | EXPORT_SYMBOL(check_disk_change); |
1318 | |
1319 | void bd_set_size(struct block_device *bdev, loff_t size) |
1320 | { |
1321 | unsigned bsize = bdev_logical_block_size(bdev); |
1322 | |
1323 | bdev->bd_inode->i_size = size; |
1324 | while (bsize < PAGE_CACHE_SIZE) { |
1325 | if (size & bsize) |
1326 | break; |
1327 | bsize <<= 1; |
1328 | } |
1329 | bdev->bd_block_size = bsize; |
1330 | bdev->bd_inode->i_blkbits = blksize_bits(bsize); |
1331 | } |
1332 | EXPORT_SYMBOL(bd_set_size); |
1333 | |
1334 | static int __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part); |
1335 | |
1336 | /* |
1337 | * bd_mutex locking: |
1338 | * |
1339 | * mutex_lock(part->bd_mutex) |
1340 | * mutex_lock_nested(whole->bd_mutex, 1) |
1341 | */ |
1342 | |
1343 | static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part) |
1344 | { |
1345 | struct gendisk *disk; |
1346 | int ret; |
1347 | int partno; |
1348 | int perm = 0; |
1349 | |
1350 | if (mode & FMODE_READ) |
1351 | perm |= MAY_READ; |
1352 | if (mode & FMODE_WRITE) |
1353 | perm |= MAY_WRITE; |
1354 | /* |
1355 | * hooks: /n/, see "layering violations". |
1356 | */ |
1357 | if (!for_part) { |
1358 | ret = devcgroup_inode_permission(bdev->bd_inode, perm); |
1359 | if (ret != 0) { |
1360 | bdput(bdev); |
1361 | return ret; |
1362 | } |
1363 | } |
1364 | |
1365 | restart: |
1366 | |
1367 | ret = -ENXIO; |
1368 | disk = get_gendisk(bdev->bd_dev, &partno); |
1369 | if (!disk) |
1370 | goto out; |
1371 | |
1372 | mutex_lock_nested(&bdev->bd_mutex, for_part); |
1373 | if (!bdev->bd_openers) { |
1374 | bdev->bd_disk = disk; |
1375 | bdev->bd_contains = bdev; |
1376 | if (!partno) { |
1377 | struct backing_dev_info *bdi; |
1378 | |
1379 | ret = -ENXIO; |
1380 | bdev->bd_part = disk_get_part(disk, partno); |
1381 | if (!bdev->bd_part) |
1382 | goto out_clear; |
1383 | |
1384 | if (disk->fops->open) { |
1385 | ret = disk->fops->open(bdev, mode); |
1386 | if (ret == -ERESTARTSYS) { |
1387 | /* Lost a race with 'disk' being |
1388 | * deleted, try again. |
1389 | * See md.c |
1390 | */ |
1391 | disk_put_part(bdev->bd_part); |
1392 | bdev->bd_part = NULL; |
1393 | module_put(disk->fops->owner); |
1394 | put_disk(disk); |
1395 | bdev->bd_disk = NULL; |
1396 | mutex_unlock(&bdev->bd_mutex); |
1397 | goto restart; |
1398 | } |
1399 | if (ret) |
1400 | goto out_clear; |
1401 | } |
1402 | if (!bdev->bd_openers) { |
1403 | bd_set_size(bdev,(loff_t)get_capacity(disk)<<9); |
1404 | bdi = blk_get_backing_dev_info(bdev); |
1405 | if (bdi == NULL) |
1406 | bdi = &default_backing_dev_info; |
1407 | bdev_inode_switch_bdi(bdev->bd_inode, bdi); |
1408 | } |
1409 | if (bdev->bd_invalidated) |
1410 | rescan_partitions(disk, bdev); |
1411 | } else { |
1412 | struct block_device *whole; |
1413 | whole = bdget_disk(disk, 0); |
1414 | ret = -ENOMEM; |
1415 | if (!whole) |
1416 | goto out_clear; |
1417 | BUG_ON(for_part); |
1418 | ret = __blkdev_get(whole, mode, 1); |
1419 | if (ret) |
1420 | goto out_clear; |
1421 | bdev->bd_contains = whole; |
1422 | bdev_inode_switch_bdi(bdev->bd_inode, |
1423 | whole->bd_inode->i_data.backing_dev_info); |
1424 | bdev->bd_part = disk_get_part(disk, partno); |
1425 | if (!(disk->flags & GENHD_FL_UP) || |
1426 | !bdev->bd_part || !bdev->bd_part->nr_sects) { |
1427 | ret = -ENXIO; |
1428 | goto out_clear; |
1429 | } |
1430 | bd_set_size(bdev, (loff_t)bdev->bd_part->nr_sects << 9); |
1431 | } |
1432 | } else { |
1433 | module_put(disk->fops->owner); |
1434 | put_disk(disk); |
1435 | disk = NULL; |
1436 | if (bdev->bd_contains == bdev) { |
1437 | if (bdev->bd_disk->fops->open) { |
1438 | ret = bdev->bd_disk->fops->open(bdev, mode); |
1439 | if (ret) |
1440 | goto out_unlock_bdev; |
1441 | } |
1442 | if (bdev->bd_invalidated) |
1443 | rescan_partitions(bdev->bd_disk, bdev); |
1444 | } |
1445 | } |
1446 | bdev->bd_openers++; |
1447 | if (for_part) |
1448 | bdev->bd_part_count++; |
1449 | mutex_unlock(&bdev->bd_mutex); |
1450 | return 0; |
1451 | |
1452 | out_clear: |
1453 | disk_put_part(bdev->bd_part); |
1454 | bdev->bd_disk = NULL; |
1455 | bdev->bd_part = NULL; |
1456 | bdev_inode_switch_bdi(bdev->bd_inode, &default_backing_dev_info); |
1457 | if (bdev != bdev->bd_contains) |
1458 | __blkdev_put(bdev->bd_contains, mode, 1); |
1459 | bdev->bd_contains = NULL; |
1460 | out_unlock_bdev: |
1461 | mutex_unlock(&bdev->bd_mutex); |
1462 | out: |
1463 | if (disk) |
1464 | module_put(disk->fops->owner); |
1465 | put_disk(disk); |
1466 | bdput(bdev); |
1467 | |
1468 | return ret; |
1469 | } |
1470 | |
1471 | int blkdev_get(struct block_device *bdev, fmode_t mode) |
1472 | { |
1473 | return __blkdev_get(bdev, mode, 0); |
1474 | } |
1475 | EXPORT_SYMBOL(blkdev_get); |
1476 | |
1477 | static int blkdev_open(struct inode * inode, struct file * filp) |
1478 | { |
1479 | struct block_device *whole = NULL; |
1480 | struct block_device *bdev; |
1481 | int res; |
1482 | |
1483 | /* |
1484 | * Preserve backwards compatibility and allow large file access |
1485 | * even if userspace doesn't ask for it explicitly. Some mkfs |
1486 | * binary needs it. We might want to drop this workaround |
1487 | * during an unstable branch. |
1488 | */ |
1489 | filp->f_flags |= O_LARGEFILE; |
1490 | |
1491 | if (filp->f_flags & O_NDELAY) |
1492 | filp->f_mode |= FMODE_NDELAY; |
1493 | if (filp->f_flags & O_EXCL) |
1494 | filp->f_mode |= FMODE_EXCL; |
1495 | if ((filp->f_flags & O_ACCMODE) == 3) |
1496 | filp->f_mode |= FMODE_WRITE_IOCTL; |
1497 | |
1498 | bdev = bd_acquire(inode); |
1499 | if (bdev == NULL) |
1500 | return -ENOMEM; |
1501 | |
1502 | if (filp->f_mode & FMODE_EXCL) { |
1503 | whole = bd_start_claiming(bdev, filp); |
1504 | if (IS_ERR(whole)) { |
1505 | bdput(bdev); |
1506 | return PTR_ERR(whole); |
1507 | } |
1508 | } |
1509 | |
1510 | filp->f_mapping = bdev->bd_inode->i_mapping; |
1511 | |
1512 | res = blkdev_get(bdev, filp->f_mode); |
1513 | |
1514 | if (whole) { |
1515 | if (res == 0) |
1516 | bd_finish_claiming(bdev, whole, filp); |
1517 | else |
1518 | bd_abort_claiming(whole, filp); |
1519 | } |
1520 | |
1521 | return res; |
1522 | } |
1523 | |
1524 | static int __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part) |
1525 | { |
1526 | int ret = 0; |
1527 | struct gendisk *disk = bdev->bd_disk; |
1528 | struct block_device *victim = NULL; |
1529 | |
1530 | mutex_lock_nested(&bdev->bd_mutex, for_part); |
1531 | if (for_part) |
1532 | bdev->bd_part_count--; |
1533 | |
1534 | if (!--bdev->bd_openers) { |
1535 | sync_blockdev(bdev); |
1536 | kill_bdev(bdev); |
1537 | } |
1538 | if (bdev->bd_contains == bdev) { |
1539 | if (disk->fops->release) |
1540 | ret = disk->fops->release(disk, mode); |
1541 | } |
1542 | if (!bdev->bd_openers) { |
1543 | struct module *owner = disk->fops->owner; |
1544 | |
1545 | put_disk(disk); |
1546 | module_put(owner); |
1547 | disk_put_part(bdev->bd_part); |
1548 | bdev->bd_part = NULL; |
1549 | bdev->bd_disk = NULL; |
1550 | bdev_inode_switch_bdi(bdev->bd_inode, |
1551 | &default_backing_dev_info); |
1552 | if (bdev != bdev->bd_contains) |
1553 | victim = bdev->bd_contains; |
1554 | bdev->bd_contains = NULL; |
1555 | } |
1556 | mutex_unlock(&bdev->bd_mutex); |
1557 | bdput(bdev); |
1558 | if (victim) |
1559 | __blkdev_put(victim, mode, 1); |
1560 | return ret; |
1561 | } |
1562 | |
1563 | int blkdev_put(struct block_device *bdev, fmode_t mode) |
1564 | { |
1565 | return __blkdev_put(bdev, mode, 0); |
1566 | } |
1567 | EXPORT_SYMBOL(blkdev_put); |
1568 | |
1569 | static int blkdev_close(struct inode * inode, struct file * filp) |
1570 | { |
1571 | struct block_device *bdev = I_BDEV(filp->f_mapping->host); |
1572 | if (bdev->bd_holder == filp) |
1573 | bd_release(bdev); |
1574 | return blkdev_put(bdev, filp->f_mode); |
1575 | } |
1576 | |
1577 | static long block_ioctl(struct file *file, unsigned cmd, unsigned long arg) |
1578 | { |
1579 | struct block_device *bdev = I_BDEV(file->f_mapping->host); |
1580 | fmode_t mode = file->f_mode; |
1581 | |
1582 | /* |
1583 | * O_NDELAY can be altered using fcntl(.., F_SETFL, ..), so we have |
1584 | * to updated it before every ioctl. |
1585 | */ |
1586 | if (file->f_flags & O_NDELAY) |
1587 | mode |= FMODE_NDELAY; |
1588 | else |
1589 | mode &= ~FMODE_NDELAY; |
1590 | |
1591 | return blkdev_ioctl(bdev, mode, cmd, arg); |
1592 | } |
1593 | |
1594 | /* |
1595 | * Write data to the block device. Only intended for the block device itself |
1596 | * and the raw driver which basically is a fake block device. |
1597 | * |
1598 | * Does not take i_mutex for the write and thus is not for general purpose |
1599 | * use. |
1600 | */ |
1601 | ssize_t blkdev_aio_write(struct kiocb *iocb, const struct iovec *iov, |
1602 | unsigned long nr_segs, loff_t pos) |
1603 | { |
1604 | struct file *file = iocb->ki_filp; |
1605 | ssize_t ret; |
1606 | |
1607 | BUG_ON(iocb->ki_pos != pos); |
1608 | |
1609 | ret = __generic_file_aio_write(iocb, iov, nr_segs, &iocb->ki_pos); |
1610 | if (ret > 0 || ret == -EIOCBQUEUED) { |
1611 | ssize_t err; |
1612 | |
1613 | err = generic_write_sync(file, pos, ret); |
1614 | if (err < 0 && ret > 0) |
1615 | ret = err; |
1616 | } |
1617 | return ret; |
1618 | } |
1619 | EXPORT_SYMBOL_GPL(blkdev_aio_write); |
1620 | |
1621 | /* |
1622 | * Try to release a page associated with block device when the system |
1623 | * is under memory pressure. |
1624 | */ |
1625 | static int blkdev_releasepage(struct page *page, gfp_t wait) |
1626 | { |
1627 | struct super_block *super = BDEV_I(page->mapping->host)->bdev.bd_super; |
1628 | |
1629 | if (super && super->s_op->bdev_try_to_free_page) |
1630 | return super->s_op->bdev_try_to_free_page(super, page, wait); |
1631 | |
1632 | return try_to_free_buffers(page); |
1633 | } |
1634 | |
1635 | static const struct address_space_operations def_blk_aops = { |
1636 | .readpage = blkdev_readpage, |
1637 | .writepage = blkdev_writepage, |
1638 | .sync_page = block_sync_page, |
1639 | .write_begin = blkdev_write_begin, |
1640 | .write_end = blkdev_write_end, |
1641 | .writepages = generic_writepages, |
1642 | .releasepage = blkdev_releasepage, |
1643 | .direct_IO = blkdev_direct_IO, |
1644 | }; |
1645 | |
1646 | const struct file_operations def_blk_fops = { |
1647 | .open = blkdev_open, |
1648 | .release = blkdev_close, |
1649 | .llseek = block_llseek, |
1650 | .read = do_sync_read, |
1651 | .write = do_sync_write, |
1652 | .aio_read = generic_file_aio_read, |
1653 | .aio_write = blkdev_aio_write, |
1654 | .mmap = generic_file_mmap, |
1655 | .fsync = blkdev_fsync, |
1656 | .unlocked_ioctl = block_ioctl, |
1657 | #ifdef CONFIG_COMPAT |
1658 | .compat_ioctl = compat_blkdev_ioctl, |
1659 | #endif |
1660 | .splice_read = generic_file_splice_read, |
1661 | .splice_write = generic_file_splice_write, |
1662 | }; |
1663 | |
1664 | int ioctl_by_bdev(struct block_device *bdev, unsigned cmd, unsigned long arg) |
1665 | { |
1666 | int res; |
1667 | mm_segment_t old_fs = get_fs(); |
1668 | set_fs(KERNEL_DS); |
1669 | res = blkdev_ioctl(bdev, 0, cmd, arg); |
1670 | set_fs(old_fs); |
1671 | return res; |
1672 | } |
1673 | |
1674 | EXPORT_SYMBOL(ioctl_by_bdev); |
1675 | |
1676 | /** |
1677 | * lookup_bdev - lookup a struct block_device by name |
1678 | * @pathname: special file representing the block device |
1679 | * |
1680 | * Get a reference to the blockdevice at @pathname in the current |
1681 | * namespace if possible and return it. Return ERR_PTR(error) |
1682 | * otherwise. |
1683 | */ |
1684 | struct block_device *lookup_bdev(const char *pathname) |
1685 | { |
1686 | struct block_device *bdev; |
1687 | struct inode *inode; |
1688 | struct path path; |
1689 | int error; |
1690 | |
1691 | if (!pathname || !*pathname) |
1692 | return ERR_PTR(-EINVAL); |
1693 | |
1694 | error = kern_path(pathname, LOOKUP_FOLLOW, &path); |
1695 | if (error) |
1696 | return ERR_PTR(error); |
1697 | |
1698 | inode = path.dentry->d_inode; |
1699 | error = -ENOTBLK; |
1700 | if (!S_ISBLK(inode->i_mode)) |
1701 | goto fail; |
1702 | error = -EACCES; |
1703 | if (path.mnt->mnt_flags & MNT_NODEV) |
1704 | goto fail; |
1705 | error = -ENOMEM; |
1706 | bdev = bd_acquire(inode); |
1707 | if (!bdev) |
1708 | goto fail; |
1709 | out: |
1710 | path_put(&path); |
1711 | return bdev; |
1712 | fail: |
1713 | bdev = ERR_PTR(error); |
1714 | goto out; |
1715 | } |
1716 | EXPORT_SYMBOL(lookup_bdev); |
1717 | |
1718 | /** |
1719 | * open_bdev_exclusive - open a block device by name and set it up for use |
1720 | * |
1721 | * @path: special file representing the block device |
1722 | * @mode: FMODE_... combination to pass be used |
1723 | * @holder: owner for exclusion |
1724 | * |
1725 | * Open the blockdevice described by the special file at @path, claim it |
1726 | * for the @holder. |
1727 | */ |
1728 | struct block_device *open_bdev_exclusive(const char *path, fmode_t mode, void *holder) |
1729 | { |
1730 | struct block_device *bdev, *whole; |
1731 | int error; |
1732 | |
1733 | bdev = lookup_bdev(path); |
1734 | if (IS_ERR(bdev)) |
1735 | return bdev; |
1736 | |
1737 | whole = bd_start_claiming(bdev, holder); |
1738 | if (IS_ERR(whole)) { |
1739 | bdput(bdev); |
1740 | return whole; |
1741 | } |
1742 | |
1743 | error = blkdev_get(bdev, mode); |
1744 | if (error) |
1745 | goto out_abort_claiming; |
1746 | |
1747 | error = -EACCES; |
1748 | if ((mode & FMODE_WRITE) && bdev_read_only(bdev)) |
1749 | goto out_blkdev_put; |
1750 | |
1751 | bd_finish_claiming(bdev, whole, holder); |
1752 | return bdev; |
1753 | |
1754 | out_blkdev_put: |
1755 | blkdev_put(bdev, mode); |
1756 | out_abort_claiming: |
1757 | bd_abort_claiming(whole, holder); |
1758 | return ERR_PTR(error); |
1759 | } |
1760 | |
1761 | EXPORT_SYMBOL(open_bdev_exclusive); |
1762 | |
1763 | /** |
1764 | * close_bdev_exclusive - close a blockdevice opened by open_bdev_exclusive() |
1765 | * |
1766 | * @bdev: blockdevice to close |
1767 | * @mode: mode, must match that used to open. |
1768 | * |
1769 | * This is the counterpart to open_bdev_exclusive(). |
1770 | */ |
1771 | void close_bdev_exclusive(struct block_device *bdev, fmode_t mode) |
1772 | { |
1773 | bd_release(bdev); |
1774 | blkdev_put(bdev, mode); |
1775 | } |
1776 | |
1777 | EXPORT_SYMBOL(close_bdev_exclusive); |
1778 | |
1779 | int __invalidate_device(struct block_device *bdev) |
1780 | { |
1781 | struct super_block *sb = get_super(bdev); |
1782 | int res = 0; |
1783 | |
1784 | if (sb) { |
1785 | /* |
1786 | * no need to lock the super, get_super holds the |
1787 | * read mutex so the filesystem cannot go away |
1788 | * under us (->put_super runs with the write lock |
1789 | * hold). |
1790 | */ |
1791 | shrink_dcache_sb(sb); |
1792 | res = invalidate_inodes(sb); |
1793 | drop_super(sb); |
1794 | } |
1795 | invalidate_bdev(bdev); |
1796 | return res; |
1797 | } |
1798 | EXPORT_SYMBOL(__invalidate_device); |
1799 |
Branches:
ben-wpan
ben-wpan-stefan
javiroman/ks7010
jz-2.6.34
jz-2.6.34-rc5
jz-2.6.34-rc6
jz-2.6.34-rc7
jz-2.6.35
jz-2.6.36
jz-2.6.37
jz-2.6.38
jz-2.6.39
jz-3.0
jz-3.1
jz-3.11
jz-3.12
jz-3.13
jz-3.15
jz-3.16
jz-3.18-dt
jz-3.2
jz-3.3
jz-3.4
jz-3.5
jz-3.6
jz-3.6-rc2-pwm
jz-3.9
jz-3.9-clk
jz-3.9-rc8
jz47xx
jz47xx-2.6.38
master
Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9