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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/fs/block_dev.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | * Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE | |
6 | */ | |
7 | ||
1da177e4 LT |
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> | |
7db9cfd3 | 14 | #include <linux/device_cgroup.h> |
1da177e4 LT |
15 | #include <linux/highmem.h> |
16 | #include <linux/blkdev.h> | |
17 | #include <linux/module.h> | |
18 | #include <linux/blkpg.h> | |
b502bd11 | 19 | #include <linux/magic.h> |
1da177e4 | 20 | #include <linux/buffer_head.h> |
ff01bb48 | 21 | #include <linux/swap.h> |
585d3bc0 | 22 | #include <linux/pagevec.h> |
811d736f | 23 | #include <linux/writeback.h> |
1da177e4 LT |
24 | #include <linux/mpage.h> |
25 | #include <linux/mount.h> | |
26 | #include <linux/uio.h> | |
27 | #include <linux/namei.h> | |
1368c4f2 | 28 | #include <linux/log2.h> |
ff01bb48 | 29 | #include <linux/cleancache.h> |
1da177e4 | 30 | #include <asm/uaccess.h> |
07f3f05c | 31 | #include "internal.h" |
1da177e4 LT |
32 | |
33 | struct bdev_inode { | |
34 | struct block_device bdev; | |
35 | struct inode vfs_inode; | |
36 | }; | |
37 | ||
4c54ac62 AB |
38 | static const struct address_space_operations def_blk_aops; |
39 | ||
1da177e4 LT |
40 | static inline struct bdev_inode *BDEV_I(struct inode *inode) |
41 | { | |
42 | return container_of(inode, struct bdev_inode, vfs_inode); | |
43 | } | |
44 | ||
45 | inline struct block_device *I_BDEV(struct inode *inode) | |
46 | { | |
47 | return &BDEV_I(inode)->bdev; | |
48 | } | |
1da177e4 LT |
49 | EXPORT_SYMBOL(I_BDEV); |
50 | ||
564f00f6 CH |
51 | static void bdev_write_inode(struct inode *inode) |
52 | { | |
53 | spin_lock(&inode->i_lock); | |
54 | while (inode->i_state & I_DIRTY) { | |
55 | spin_unlock(&inode->i_lock); | |
56 | WARN_ON_ONCE(write_inode_now(inode, true)); | |
57 | spin_lock(&inode->i_lock); | |
58 | } | |
59 | spin_unlock(&inode->i_lock); | |
60 | } | |
61 | ||
f9a14399 | 62 | /* Kill _all_ buffers and pagecache , dirty or not.. */ |
ff01bb48 | 63 | void kill_bdev(struct block_device *bdev) |
1da177e4 | 64 | { |
ff01bb48 AV |
65 | struct address_space *mapping = bdev->bd_inode->i_mapping; |
66 | ||
91b0abe3 | 67 | if (mapping->nrpages == 0 && mapping->nrshadows == 0) |
f9a14399 | 68 | return; |
ff01bb48 | 69 | |
f9a14399 | 70 | invalidate_bh_lrus(); |
ff01bb48 | 71 | truncate_inode_pages(mapping, 0); |
1da177e4 | 72 | } |
ff01bb48 AV |
73 | EXPORT_SYMBOL(kill_bdev); |
74 | ||
75 | /* Invalidate clean unused buffers and pagecache. */ | |
76 | void invalidate_bdev(struct block_device *bdev) | |
77 | { | |
78 | struct address_space *mapping = bdev->bd_inode->i_mapping; | |
79 | ||
80 | if (mapping->nrpages == 0) | |
81 | return; | |
82 | ||
83 | invalidate_bh_lrus(); | |
84 | lru_add_drain_all(); /* make sure all lru add caches are flushed */ | |
85 | invalidate_mapping_pages(mapping, 0, -1); | |
86 | /* 99% of the time, we don't need to flush the cleancache on the bdev. | |
87 | * But, for the strange corners, lets be cautious | |
88 | */ | |
3167760f | 89 | cleancache_invalidate_inode(mapping); |
ff01bb48 AV |
90 | } |
91 | EXPORT_SYMBOL(invalidate_bdev); | |
1da177e4 LT |
92 | |
93 | int set_blocksize(struct block_device *bdev, int size) | |
94 | { | |
95 | /* Size must be a power of two, and between 512 and PAGE_SIZE */ | |
1368c4f2 | 96 | if (size > PAGE_SIZE || size < 512 || !is_power_of_2(size)) |
1da177e4 LT |
97 | return -EINVAL; |
98 | ||
99 | /* Size cannot be smaller than the size supported by the device */ | |
e1defc4f | 100 | if (size < bdev_logical_block_size(bdev)) |
1da177e4 LT |
101 | return -EINVAL; |
102 | ||
103 | /* Don't change the size if it is same as current */ | |
104 | if (bdev->bd_block_size != size) { | |
105 | sync_blockdev(bdev); | |
106 | bdev->bd_block_size = size; | |
107 | bdev->bd_inode->i_blkbits = blksize_bits(size); | |
108 | kill_bdev(bdev); | |
109 | } | |
110 | return 0; | |
111 | } | |
112 | ||
113 | EXPORT_SYMBOL(set_blocksize); | |
114 | ||
115 | int sb_set_blocksize(struct super_block *sb, int size) | |
116 | { | |
1da177e4 LT |
117 | if (set_blocksize(sb->s_bdev, size)) |
118 | return 0; | |
119 | /* If we get here, we know size is power of two | |
120 | * and it's value is between 512 and PAGE_SIZE */ | |
121 | sb->s_blocksize = size; | |
38885bd4 | 122 | sb->s_blocksize_bits = blksize_bits(size); |
1da177e4 LT |
123 | return sb->s_blocksize; |
124 | } | |
125 | ||
126 | EXPORT_SYMBOL(sb_set_blocksize); | |
127 | ||
128 | int sb_min_blocksize(struct super_block *sb, int size) | |
129 | { | |
e1defc4f | 130 | int minsize = bdev_logical_block_size(sb->s_bdev); |
1da177e4 LT |
131 | if (size < minsize) |
132 | size = minsize; | |
133 | return sb_set_blocksize(sb, size); | |
134 | } | |
135 | ||
136 | EXPORT_SYMBOL(sb_min_blocksize); | |
137 | ||
138 | static int | |
139 | blkdev_get_block(struct inode *inode, sector_t iblock, | |
140 | struct buffer_head *bh, int create) | |
141 | { | |
1da177e4 LT |
142 | bh->b_bdev = I_BDEV(inode); |
143 | bh->b_blocknr = iblock; | |
144 | set_buffer_mapped(bh); | |
145 | return 0; | |
146 | } | |
147 | ||
b2e895db | 148 | static ssize_t |
22c6186e | 149 | blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, loff_t offset) |
b2e895db AM |
150 | { |
151 | struct file *file = iocb->ki_filp; | |
152 | struct inode *inode = file->f_mapping->host; | |
153 | ||
bbab37dd MW |
154 | if (IS_DAX(inode)) |
155 | return dax_do_io(iocb, inode, iter, offset, blkdev_get_block, | |
156 | NULL, DIO_SKIP_DIO_COUNT); | |
17f8c842 | 157 | return __blockdev_direct_IO(iocb, inode, I_BDEV(inode), iter, offset, |
fe0f07d0 JA |
158 | blkdev_get_block, NULL, NULL, |
159 | DIO_SKIP_DIO_COUNT); | |
b2e895db AM |
160 | } |
161 | ||
5cee5815 JK |
162 | int __sync_blockdev(struct block_device *bdev, int wait) |
163 | { | |
164 | if (!bdev) | |
165 | return 0; | |
166 | if (!wait) | |
167 | return filemap_flush(bdev->bd_inode->i_mapping); | |
168 | return filemap_write_and_wait(bdev->bd_inode->i_mapping); | |
169 | } | |
170 | ||
585d3bc0 NP |
171 | /* |
172 | * Write out and wait upon all the dirty data associated with a block | |
173 | * device via its mapping. Does not take the superblock lock. | |
174 | */ | |
175 | int sync_blockdev(struct block_device *bdev) | |
176 | { | |
5cee5815 | 177 | return __sync_blockdev(bdev, 1); |
585d3bc0 NP |
178 | } |
179 | EXPORT_SYMBOL(sync_blockdev); | |
180 | ||
181 | /* | |
182 | * Write out and wait upon all dirty data associated with this | |
183 | * device. Filesystem data as well as the underlying block | |
184 | * device. Takes the superblock lock. | |
185 | */ | |
186 | int fsync_bdev(struct block_device *bdev) | |
187 | { | |
188 | struct super_block *sb = get_super(bdev); | |
189 | if (sb) { | |
60b0680f | 190 | int res = sync_filesystem(sb); |
585d3bc0 NP |
191 | drop_super(sb); |
192 | return res; | |
193 | } | |
194 | return sync_blockdev(bdev); | |
195 | } | |
47e4491b | 196 | EXPORT_SYMBOL(fsync_bdev); |
585d3bc0 NP |
197 | |
198 | /** | |
199 | * freeze_bdev -- lock a filesystem and force it into a consistent state | |
200 | * @bdev: blockdevice to lock | |
201 | * | |
585d3bc0 NP |
202 | * If a superblock is found on this device, we take the s_umount semaphore |
203 | * on it to make sure nobody unmounts until the snapshot creation is done. | |
204 | * The reference counter (bd_fsfreeze_count) guarantees that only the last | |
205 | * unfreeze process can unfreeze the frozen filesystem actually when multiple | |
206 | * freeze requests arrive simultaneously. It counts up in freeze_bdev() and | |
207 | * count down in thaw_bdev(). When it becomes 0, thaw_bdev() will unfreeze | |
208 | * actually. | |
209 | */ | |
210 | struct super_block *freeze_bdev(struct block_device *bdev) | |
211 | { | |
212 | struct super_block *sb; | |
213 | int error = 0; | |
214 | ||
215 | mutex_lock(&bdev->bd_fsfreeze_mutex); | |
4504230a CH |
216 | if (++bdev->bd_fsfreeze_count > 1) { |
217 | /* | |
218 | * We don't even need to grab a reference - the first call | |
219 | * to freeze_bdev grab an active reference and only the last | |
220 | * thaw_bdev drops it. | |
221 | */ | |
585d3bc0 | 222 | sb = get_super(bdev); |
4504230a CH |
223 | drop_super(sb); |
224 | mutex_unlock(&bdev->bd_fsfreeze_mutex); | |
225 | return sb; | |
226 | } | |
227 | ||
228 | sb = get_active_super(bdev); | |
229 | if (!sb) | |
230 | goto out; | |
48b6bca6 BM |
231 | if (sb->s_op->freeze_super) |
232 | error = sb->s_op->freeze_super(sb); | |
233 | else | |
234 | error = freeze_super(sb); | |
18e9e510 JB |
235 | if (error) { |
236 | deactivate_super(sb); | |
237 | bdev->bd_fsfreeze_count--; | |
585d3bc0 | 238 | mutex_unlock(&bdev->bd_fsfreeze_mutex); |
18e9e510 | 239 | return ERR_PTR(error); |
585d3bc0 | 240 | } |
18e9e510 | 241 | deactivate_super(sb); |
4504230a | 242 | out: |
585d3bc0 NP |
243 | sync_blockdev(bdev); |
244 | mutex_unlock(&bdev->bd_fsfreeze_mutex); | |
4fadd7bb | 245 | return sb; /* thaw_bdev releases s->s_umount */ |
585d3bc0 NP |
246 | } |
247 | EXPORT_SYMBOL(freeze_bdev); | |
248 | ||
249 | /** | |
250 | * thaw_bdev -- unlock filesystem | |
251 | * @bdev: blockdevice to unlock | |
252 | * @sb: associated superblock | |
253 | * | |
254 | * Unlocks the filesystem and marks it writeable again after freeze_bdev(). | |
255 | */ | |
256 | int thaw_bdev(struct block_device *bdev, struct super_block *sb) | |
257 | { | |
4504230a | 258 | int error = -EINVAL; |
585d3bc0 NP |
259 | |
260 | mutex_lock(&bdev->bd_fsfreeze_mutex); | |
4504230a | 261 | if (!bdev->bd_fsfreeze_count) |
18e9e510 | 262 | goto out; |
4504230a CH |
263 | |
264 | error = 0; | |
265 | if (--bdev->bd_fsfreeze_count > 0) | |
18e9e510 | 266 | goto out; |
4504230a CH |
267 | |
268 | if (!sb) | |
18e9e510 | 269 | goto out; |
4504230a | 270 | |
48b6bca6 BM |
271 | if (sb->s_op->thaw_super) |
272 | error = sb->s_op->thaw_super(sb); | |
273 | else | |
274 | error = thaw_super(sb); | |
18e9e510 JB |
275 | if (error) { |
276 | bdev->bd_fsfreeze_count++; | |
277 | mutex_unlock(&bdev->bd_fsfreeze_mutex); | |
278 | return error; | |
279 | } | |
280 | out: | |
585d3bc0 NP |
281 | mutex_unlock(&bdev->bd_fsfreeze_mutex); |
282 | return 0; | |
283 | } | |
284 | EXPORT_SYMBOL(thaw_bdev); | |
285 | ||
1da177e4 LT |
286 | static int blkdev_writepage(struct page *page, struct writeback_control *wbc) |
287 | { | |
288 | return block_write_full_page(page, blkdev_get_block, wbc); | |
289 | } | |
290 | ||
291 | static int blkdev_readpage(struct file * file, struct page * page) | |
292 | { | |
293 | return block_read_full_page(page, blkdev_get_block); | |
294 | } | |
295 | ||
447f05bb AM |
296 | static int blkdev_readpages(struct file *file, struct address_space *mapping, |
297 | struct list_head *pages, unsigned nr_pages) | |
298 | { | |
299 | return mpage_readpages(mapping, pages, nr_pages, blkdev_get_block); | |
300 | } | |
301 | ||
6272b5a5 NP |
302 | static int blkdev_write_begin(struct file *file, struct address_space *mapping, |
303 | loff_t pos, unsigned len, unsigned flags, | |
304 | struct page **pagep, void **fsdata) | |
1da177e4 | 305 | { |
155130a4 CH |
306 | return block_write_begin(mapping, pos, len, flags, pagep, |
307 | blkdev_get_block); | |
1da177e4 LT |
308 | } |
309 | ||
6272b5a5 NP |
310 | static int blkdev_write_end(struct file *file, struct address_space *mapping, |
311 | loff_t pos, unsigned len, unsigned copied, | |
312 | struct page *page, void *fsdata) | |
1da177e4 | 313 | { |
6272b5a5 NP |
314 | int ret; |
315 | ret = block_write_end(file, mapping, pos, len, copied, page, fsdata); | |
316 | ||
317 | unlock_page(page); | |
318 | page_cache_release(page); | |
319 | ||
320 | return ret; | |
1da177e4 LT |
321 | } |
322 | ||
323 | /* | |
324 | * private llseek: | |
496ad9aa | 325 | * for a block special file file_inode(file)->i_size is zero |
1da177e4 LT |
326 | * so we compute the size by hand (just as in block_read/write above) |
327 | */ | |
965c8e59 | 328 | static loff_t block_llseek(struct file *file, loff_t offset, int whence) |
1da177e4 LT |
329 | { |
330 | struct inode *bd_inode = file->f_mapping->host; | |
1da177e4 LT |
331 | loff_t retval; |
332 | ||
1b1dcc1b | 333 | mutex_lock(&bd_inode->i_mutex); |
5d48f3a2 | 334 | retval = fixed_size_llseek(file, offset, whence, i_size_read(bd_inode)); |
1b1dcc1b | 335 | mutex_unlock(&bd_inode->i_mutex); |
1da177e4 LT |
336 | return retval; |
337 | } | |
338 | ||
02c24a82 | 339 | int blkdev_fsync(struct file *filp, loff_t start, loff_t end, int datasync) |
1da177e4 | 340 | { |
b8af67e2 AB |
341 | struct inode *bd_inode = filp->f_mapping->host; |
342 | struct block_device *bdev = I_BDEV(bd_inode); | |
ab0a9735 | 343 | int error; |
da5aa861 RW |
344 | |
345 | error = filemap_write_and_wait_range(filp->f_mapping, start, end); | |
346 | if (error) | |
347 | return error; | |
ab0a9735 | 348 | |
b8af67e2 AB |
349 | /* |
350 | * There is no need to serialise calls to blkdev_issue_flush with | |
351 | * i_mutex and doing so causes performance issues with concurrent | |
352 | * O_SYNC writers to a block device. | |
353 | */ | |
dd3932ed | 354 | error = blkdev_issue_flush(bdev, GFP_KERNEL, NULL); |
ab0a9735 CH |
355 | if (error == -EOPNOTSUPP) |
356 | error = 0; | |
b8af67e2 | 357 | |
ab0a9735 | 358 | return error; |
1da177e4 | 359 | } |
b1dd3b28 | 360 | EXPORT_SYMBOL(blkdev_fsync); |
1da177e4 | 361 | |
47a191fd MW |
362 | /** |
363 | * bdev_read_page() - Start reading a page from a block device | |
364 | * @bdev: The device to read the page from | |
365 | * @sector: The offset on the device to read the page to (need not be aligned) | |
366 | * @page: The page to read | |
367 | * | |
368 | * On entry, the page should be locked. It will be unlocked when the page | |
369 | * has been read. If the block driver implements rw_page synchronously, | |
370 | * that will be true on exit from this function, but it need not be. | |
371 | * | |
372 | * Errors returned by this function are usually "soft", eg out of memory, or | |
373 | * queue full; callers should try a different route to read this page rather | |
374 | * than propagate an error back up the stack. | |
375 | * | |
376 | * Return: negative errno if an error occurs, 0 if submission was successful. | |
377 | */ | |
378 | int bdev_read_page(struct block_device *bdev, sector_t sector, | |
379 | struct page *page) | |
380 | { | |
381 | const struct block_device_operations *ops = bdev->bd_disk->fops; | |
382 | if (!ops->rw_page) | |
383 | return -EOPNOTSUPP; | |
384 | return ops->rw_page(bdev, sector + get_start_sect(bdev), page, READ); | |
385 | } | |
386 | EXPORT_SYMBOL_GPL(bdev_read_page); | |
387 | ||
388 | /** | |
389 | * bdev_write_page() - Start writing a page to a block device | |
390 | * @bdev: The device to write the page to | |
391 | * @sector: The offset on the device to write the page to (need not be aligned) | |
392 | * @page: The page to write | |
393 | * @wbc: The writeback_control for the write | |
394 | * | |
395 | * On entry, the page should be locked and not currently under writeback. | |
396 | * On exit, if the write started successfully, the page will be unlocked and | |
397 | * under writeback. If the write failed already (eg the driver failed to | |
398 | * queue the page to the device), the page will still be locked. If the | |
399 | * caller is a ->writepage implementation, it will need to unlock the page. | |
400 | * | |
401 | * Errors returned by this function are usually "soft", eg out of memory, or | |
402 | * queue full; callers should try a different route to write this page rather | |
403 | * than propagate an error back up the stack. | |
404 | * | |
405 | * Return: negative errno if an error occurs, 0 if submission was successful. | |
406 | */ | |
407 | int bdev_write_page(struct block_device *bdev, sector_t sector, | |
408 | struct page *page, struct writeback_control *wbc) | |
409 | { | |
410 | int result; | |
411 | int rw = (wbc->sync_mode == WB_SYNC_ALL) ? WRITE_SYNC : WRITE; | |
412 | const struct block_device_operations *ops = bdev->bd_disk->fops; | |
413 | if (!ops->rw_page) | |
414 | return -EOPNOTSUPP; | |
415 | set_page_writeback(page); | |
416 | result = ops->rw_page(bdev, sector + get_start_sect(bdev), page, rw); | |
417 | if (result) | |
418 | end_page_writeback(page); | |
419 | else | |
420 | unlock_page(page); | |
421 | return result; | |
422 | } | |
423 | EXPORT_SYMBOL_GPL(bdev_write_page); | |
424 | ||
dd22f551 MW |
425 | /** |
426 | * bdev_direct_access() - Get the address for directly-accessibly memory | |
427 | * @bdev: The device containing the memory | |
428 | * @sector: The offset within the device | |
429 | * @addr: Where to put the address of the memory | |
430 | * @pfn: The Page Frame Number for the memory | |
431 | * @size: The number of bytes requested | |
432 | * | |
433 | * If a block device is made up of directly addressable memory, this function | |
434 | * will tell the caller the PFN and the address of the memory. The address | |
435 | * may be directly dereferenced within the kernel without the need to call | |
436 | * ioremap(), kmap() or similar. The PFN is suitable for inserting into | |
437 | * page tables. | |
438 | * | |
439 | * Return: negative errno if an error occurs, otherwise the number of bytes | |
440 | * accessible at this address. | |
441 | */ | |
442 | long bdev_direct_access(struct block_device *bdev, sector_t sector, | |
443 | void **addr, unsigned long *pfn, long size) | |
444 | { | |
445 | long avail; | |
446 | const struct block_device_operations *ops = bdev->bd_disk->fops; | |
447 | ||
43c3dd08 MW |
448 | /* |
449 | * The device driver is allowed to sleep, in order to make the | |
450 | * memory directly accessible. | |
451 | */ | |
452 | might_sleep(); | |
453 | ||
dd22f551 MW |
454 | if (size < 0) |
455 | return size; | |
456 | if (!ops->direct_access) | |
457 | return -EOPNOTSUPP; | |
458 | if ((sector + DIV_ROUND_UP(size, 512)) > | |
459 | part_nr_sects_read(bdev->bd_part)) | |
460 | return -ERANGE; | |
461 | sector += get_start_sect(bdev); | |
462 | if (sector % (PAGE_SIZE / 512)) | |
463 | return -EINVAL; | |
464 | avail = ops->direct_access(bdev, sector, addr, pfn, size); | |
465 | if (!avail) | |
466 | return -ERANGE; | |
467 | return min(avail, size); | |
468 | } | |
469 | EXPORT_SYMBOL_GPL(bdev_direct_access); | |
470 | ||
1da177e4 LT |
471 | /* |
472 | * pseudo-fs | |
473 | */ | |
474 | ||
475 | static __cacheline_aligned_in_smp DEFINE_SPINLOCK(bdev_lock); | |
e18b890b | 476 | static struct kmem_cache * bdev_cachep __read_mostly; |
1da177e4 LT |
477 | |
478 | static struct inode *bdev_alloc_inode(struct super_block *sb) | |
479 | { | |
e94b1766 | 480 | struct bdev_inode *ei = kmem_cache_alloc(bdev_cachep, GFP_KERNEL); |
1da177e4 LT |
481 | if (!ei) |
482 | return NULL; | |
483 | return &ei->vfs_inode; | |
484 | } | |
485 | ||
fa0d7e3d | 486 | static void bdev_i_callback(struct rcu_head *head) |
1da177e4 | 487 | { |
fa0d7e3d | 488 | struct inode *inode = container_of(head, struct inode, i_rcu); |
1da177e4 LT |
489 | struct bdev_inode *bdi = BDEV_I(inode); |
490 | ||
1da177e4 LT |
491 | kmem_cache_free(bdev_cachep, bdi); |
492 | } | |
493 | ||
fa0d7e3d NP |
494 | static void bdev_destroy_inode(struct inode *inode) |
495 | { | |
496 | call_rcu(&inode->i_rcu, bdev_i_callback); | |
497 | } | |
498 | ||
51cc5068 | 499 | static void init_once(void *foo) |
1da177e4 LT |
500 | { |
501 | struct bdev_inode *ei = (struct bdev_inode *) foo; | |
502 | struct block_device *bdev = &ei->bdev; | |
503 | ||
a35afb83 CL |
504 | memset(bdev, 0, sizeof(*bdev)); |
505 | mutex_init(&bdev->bd_mutex); | |
a35afb83 CL |
506 | INIT_LIST_HEAD(&bdev->bd_inodes); |
507 | INIT_LIST_HEAD(&bdev->bd_list); | |
49731baa TH |
508 | #ifdef CONFIG_SYSFS |
509 | INIT_LIST_HEAD(&bdev->bd_holder_disks); | |
510 | #endif | |
a35afb83 | 511 | inode_init_once(&ei->vfs_inode); |
fcccf502 TS |
512 | /* Initialize mutex for freeze. */ |
513 | mutex_init(&bdev->bd_fsfreeze_mutex); | |
1da177e4 LT |
514 | } |
515 | ||
516 | static inline void __bd_forget(struct inode *inode) | |
517 | { | |
518 | list_del_init(&inode->i_devices); | |
519 | inode->i_bdev = NULL; | |
520 | inode->i_mapping = &inode->i_data; | |
521 | } | |
522 | ||
b57922d9 | 523 | static void bdev_evict_inode(struct inode *inode) |
1da177e4 LT |
524 | { |
525 | struct block_device *bdev = &BDEV_I(inode)->bdev; | |
526 | struct list_head *p; | |
91b0abe3 | 527 | truncate_inode_pages_final(&inode->i_data); |
b57922d9 | 528 | invalidate_inode_buffers(inode); /* is it needed here? */ |
dbd5768f | 529 | clear_inode(inode); |
1da177e4 LT |
530 | spin_lock(&bdev_lock); |
531 | while ( (p = bdev->bd_inodes.next) != &bdev->bd_inodes ) { | |
532 | __bd_forget(list_entry(p, struct inode, i_devices)); | |
533 | } | |
534 | list_del_init(&bdev->bd_list); | |
535 | spin_unlock(&bdev_lock); | |
536 | } | |
537 | ||
ee9b6d61 | 538 | static const struct super_operations bdev_sops = { |
1da177e4 LT |
539 | .statfs = simple_statfs, |
540 | .alloc_inode = bdev_alloc_inode, | |
541 | .destroy_inode = bdev_destroy_inode, | |
542 | .drop_inode = generic_delete_inode, | |
b57922d9 | 543 | .evict_inode = bdev_evict_inode, |
1da177e4 LT |
544 | }; |
545 | ||
51139ada AV |
546 | static struct dentry *bd_mount(struct file_system_type *fs_type, |
547 | int flags, const char *dev_name, void *data) | |
1da177e4 | 548 | { |
b502bd11 | 549 | return mount_pseudo(fs_type, "bdev:", &bdev_sops, NULL, BDEVFS_MAGIC); |
1da177e4 LT |
550 | } |
551 | ||
552 | static struct file_system_type bd_type = { | |
553 | .name = "bdev", | |
51139ada | 554 | .mount = bd_mount, |
1da177e4 LT |
555 | .kill_sb = kill_anon_super, |
556 | }; | |
557 | ||
f47ec3f2 | 558 | static struct super_block *blockdev_superblock __read_mostly; |
1da177e4 LT |
559 | |
560 | void __init bdev_cache_init(void) | |
561 | { | |
562 | int err; | |
ace8577a | 563 | static struct vfsmount *bd_mnt; |
c2acf7b9 | 564 | |
1da177e4 | 565 | bdev_cachep = kmem_cache_create("bdev_cache", sizeof(struct bdev_inode), |
fffb60f9 PJ |
566 | 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT| |
567 | SLAB_MEM_SPREAD|SLAB_PANIC), | |
20c2df83 | 568 | init_once); |
1da177e4 LT |
569 | err = register_filesystem(&bd_type); |
570 | if (err) | |
571 | panic("Cannot register bdev pseudo-fs"); | |
572 | bd_mnt = kern_mount(&bd_type); | |
1da177e4 LT |
573 | if (IS_ERR(bd_mnt)) |
574 | panic("Cannot create bdev pseudo-fs"); | |
ace8577a | 575 | blockdev_superblock = bd_mnt->mnt_sb; /* For writeback */ |
1da177e4 LT |
576 | } |
577 | ||
578 | /* | |
579 | * Most likely _very_ bad one - but then it's hardly critical for small | |
580 | * /dev and can be fixed when somebody will need really large one. | |
581 | * Keep in mind that it will be fed through icache hash function too. | |
582 | */ | |
583 | static inline unsigned long hash(dev_t dev) | |
584 | { | |
585 | return MAJOR(dev)+MINOR(dev); | |
586 | } | |
587 | ||
588 | static int bdev_test(struct inode *inode, void *data) | |
589 | { | |
590 | return BDEV_I(inode)->bdev.bd_dev == *(dev_t *)data; | |
591 | } | |
592 | ||
593 | static int bdev_set(struct inode *inode, void *data) | |
594 | { | |
595 | BDEV_I(inode)->bdev.bd_dev = *(dev_t *)data; | |
596 | return 0; | |
597 | } | |
598 | ||
599 | static LIST_HEAD(all_bdevs); | |
600 | ||
601 | struct block_device *bdget(dev_t dev) | |
602 | { | |
603 | struct block_device *bdev; | |
604 | struct inode *inode; | |
605 | ||
c2acf7b9 | 606 | inode = iget5_locked(blockdev_superblock, hash(dev), |
1da177e4 LT |
607 | bdev_test, bdev_set, &dev); |
608 | ||
609 | if (!inode) | |
610 | return NULL; | |
611 | ||
612 | bdev = &BDEV_I(inode)->bdev; | |
613 | ||
614 | if (inode->i_state & I_NEW) { | |
615 | bdev->bd_contains = NULL; | |
782b94cd | 616 | bdev->bd_super = NULL; |
1da177e4 LT |
617 | bdev->bd_inode = inode; |
618 | bdev->bd_block_size = (1 << inode->i_blkbits); | |
619 | bdev->bd_part_count = 0; | |
620 | bdev->bd_invalidated = 0; | |
621 | inode->i_mode = S_IFBLK; | |
622 | inode->i_rdev = dev; | |
623 | inode->i_bdev = bdev; | |
624 | inode->i_data.a_ops = &def_blk_aops; | |
625 | mapping_set_gfp_mask(&inode->i_data, GFP_USER); | |
1da177e4 LT |
626 | spin_lock(&bdev_lock); |
627 | list_add(&bdev->bd_list, &all_bdevs); | |
628 | spin_unlock(&bdev_lock); | |
629 | unlock_new_inode(inode); | |
630 | } | |
631 | return bdev; | |
632 | } | |
633 | ||
634 | EXPORT_SYMBOL(bdget); | |
635 | ||
dddac6a7 AJ |
636 | /** |
637 | * bdgrab -- Grab a reference to an already referenced block device | |
638 | * @bdev: Block device to grab a reference to. | |
639 | */ | |
640 | struct block_device *bdgrab(struct block_device *bdev) | |
641 | { | |
7de9c6ee | 642 | ihold(bdev->bd_inode); |
dddac6a7 AJ |
643 | return bdev; |
644 | } | |
c1681bf8 | 645 | EXPORT_SYMBOL(bdgrab); |
dddac6a7 | 646 | |
1da177e4 LT |
647 | long nr_blockdev_pages(void) |
648 | { | |
203a2935 | 649 | struct block_device *bdev; |
1da177e4 LT |
650 | long ret = 0; |
651 | spin_lock(&bdev_lock); | |
203a2935 | 652 | list_for_each_entry(bdev, &all_bdevs, bd_list) { |
1da177e4 LT |
653 | ret += bdev->bd_inode->i_mapping->nrpages; |
654 | } | |
655 | spin_unlock(&bdev_lock); | |
656 | return ret; | |
657 | } | |
658 | ||
659 | void bdput(struct block_device *bdev) | |
660 | { | |
661 | iput(bdev->bd_inode); | |
662 | } | |
663 | ||
664 | EXPORT_SYMBOL(bdput); | |
665 | ||
666 | static struct block_device *bd_acquire(struct inode *inode) | |
667 | { | |
668 | struct block_device *bdev; | |
09d967c6 | 669 | |
1da177e4 LT |
670 | spin_lock(&bdev_lock); |
671 | bdev = inode->i_bdev; | |
09d967c6 | 672 | if (bdev) { |
7de9c6ee | 673 | ihold(bdev->bd_inode); |
1da177e4 LT |
674 | spin_unlock(&bdev_lock); |
675 | return bdev; | |
676 | } | |
677 | spin_unlock(&bdev_lock); | |
09d967c6 | 678 | |
1da177e4 LT |
679 | bdev = bdget(inode->i_rdev); |
680 | if (bdev) { | |
681 | spin_lock(&bdev_lock); | |
09d967c6 OH |
682 | if (!inode->i_bdev) { |
683 | /* | |
7de9c6ee | 684 | * We take an additional reference to bd_inode, |
09d967c6 OH |
685 | * and it's released in clear_inode() of inode. |
686 | * So, we can access it via ->i_mapping always | |
687 | * without igrab(). | |
688 | */ | |
7de9c6ee | 689 | ihold(bdev->bd_inode); |
09d967c6 OH |
690 | inode->i_bdev = bdev; |
691 | inode->i_mapping = bdev->bd_inode->i_mapping; | |
692 | list_add(&inode->i_devices, &bdev->bd_inodes); | |
693 | } | |
1da177e4 LT |
694 | spin_unlock(&bdev_lock); |
695 | } | |
696 | return bdev; | |
697 | } | |
698 | ||
a8855990 | 699 | int sb_is_blkdev_sb(struct super_block *sb) |
f47ec3f2 AV |
700 | { |
701 | return sb == blockdev_superblock; | |
702 | } | |
703 | ||
1da177e4 LT |
704 | /* Call when you free inode */ |
705 | ||
706 | void bd_forget(struct inode *inode) | |
707 | { | |
09d967c6 OH |
708 | struct block_device *bdev = NULL; |
709 | ||
1da177e4 | 710 | spin_lock(&bdev_lock); |
b4ea2eaa YH |
711 | if (!sb_is_blkdev_sb(inode->i_sb)) |
712 | bdev = inode->i_bdev; | |
713 | __bd_forget(inode); | |
1da177e4 | 714 | spin_unlock(&bdev_lock); |
09d967c6 OH |
715 | |
716 | if (bdev) | |
717 | iput(bdev->bd_inode); | |
1da177e4 LT |
718 | } |
719 | ||
1a3cbbc5 TH |
720 | /** |
721 | * bd_may_claim - test whether a block device can be claimed | |
722 | * @bdev: block device of interest | |
723 | * @whole: whole block device containing @bdev, may equal @bdev | |
724 | * @holder: holder trying to claim @bdev | |
725 | * | |
25985edc | 726 | * Test whether @bdev can be claimed by @holder. |
1a3cbbc5 TH |
727 | * |
728 | * CONTEXT: | |
729 | * spin_lock(&bdev_lock). | |
730 | * | |
731 | * RETURNS: | |
732 | * %true if @bdev can be claimed, %false otherwise. | |
733 | */ | |
734 | static bool bd_may_claim(struct block_device *bdev, struct block_device *whole, | |
735 | void *holder) | |
1da177e4 | 736 | { |
1da177e4 | 737 | if (bdev->bd_holder == holder) |
1a3cbbc5 | 738 | return true; /* already a holder */ |
1da177e4 | 739 | else if (bdev->bd_holder != NULL) |
1a3cbbc5 | 740 | return false; /* held by someone else */ |
1da177e4 | 741 | else if (bdev->bd_contains == bdev) |
1a3cbbc5 | 742 | return true; /* is a whole device which isn't held */ |
1da177e4 | 743 | |
e525fd89 | 744 | else if (whole->bd_holder == bd_may_claim) |
1a3cbbc5 TH |
745 | return true; /* is a partition of a device that is being partitioned */ |
746 | else if (whole->bd_holder != NULL) | |
747 | return false; /* is a partition of a held device */ | |
1da177e4 | 748 | else |
1a3cbbc5 TH |
749 | return true; /* is a partition of an un-held device */ |
750 | } | |
751 | ||
6b4517a7 TH |
752 | /** |
753 | * bd_prepare_to_claim - prepare to claim a block device | |
754 | * @bdev: block device of interest | |
755 | * @whole: the whole device containing @bdev, may equal @bdev | |
756 | * @holder: holder trying to claim @bdev | |
757 | * | |
758 | * Prepare to claim @bdev. This function fails if @bdev is already | |
759 | * claimed by another holder and waits if another claiming is in | |
760 | * progress. This function doesn't actually claim. On successful | |
761 | * return, the caller has ownership of bd_claiming and bd_holder[s]. | |
762 | * | |
763 | * CONTEXT: | |
764 | * spin_lock(&bdev_lock). Might release bdev_lock, sleep and regrab | |
765 | * it multiple times. | |
766 | * | |
767 | * RETURNS: | |
768 | * 0 if @bdev can be claimed, -EBUSY otherwise. | |
769 | */ | |
770 | static int bd_prepare_to_claim(struct block_device *bdev, | |
771 | struct block_device *whole, void *holder) | |
772 | { | |
773 | retry: | |
774 | /* if someone else claimed, fail */ | |
775 | if (!bd_may_claim(bdev, whole, holder)) | |
776 | return -EBUSY; | |
777 | ||
e75aa858 TH |
778 | /* if claiming is already in progress, wait for it to finish */ |
779 | if (whole->bd_claiming) { | |
6b4517a7 TH |
780 | wait_queue_head_t *wq = bit_waitqueue(&whole->bd_claiming, 0); |
781 | DEFINE_WAIT(wait); | |
782 | ||
783 | prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE); | |
784 | spin_unlock(&bdev_lock); | |
785 | schedule(); | |
786 | finish_wait(wq, &wait); | |
787 | spin_lock(&bdev_lock); | |
788 | goto retry; | |
789 | } | |
790 | ||
791 | /* yay, all mine */ | |
792 | return 0; | |
793 | } | |
794 | ||
795 | /** | |
796 | * bd_start_claiming - start claiming a block device | |
797 | * @bdev: block device of interest | |
798 | * @holder: holder trying to claim @bdev | |
799 | * | |
800 | * @bdev is about to be opened exclusively. Check @bdev can be opened | |
801 | * exclusively and mark that an exclusive open is in progress. Each | |
802 | * successful call to this function must be matched with a call to | |
b0018361 NP |
803 | * either bd_finish_claiming() or bd_abort_claiming() (which do not |
804 | * fail). | |
805 | * | |
806 | * This function is used to gain exclusive access to the block device | |
807 | * without actually causing other exclusive open attempts to fail. It | |
808 | * should be used when the open sequence itself requires exclusive | |
809 | * access but may subsequently fail. | |
6b4517a7 TH |
810 | * |
811 | * CONTEXT: | |
812 | * Might sleep. | |
813 | * | |
814 | * RETURNS: | |
815 | * Pointer to the block device containing @bdev on success, ERR_PTR() | |
816 | * value on failure. | |
817 | */ | |
818 | static struct block_device *bd_start_claiming(struct block_device *bdev, | |
819 | void *holder) | |
820 | { | |
821 | struct gendisk *disk; | |
822 | struct block_device *whole; | |
823 | int partno, err; | |
824 | ||
825 | might_sleep(); | |
826 | ||
827 | /* | |
828 | * @bdev might not have been initialized properly yet, look up | |
829 | * and grab the outer block device the hard way. | |
830 | */ | |
831 | disk = get_gendisk(bdev->bd_dev, &partno); | |
832 | if (!disk) | |
833 | return ERR_PTR(-ENXIO); | |
834 | ||
d4c208b8 TH |
835 | /* |
836 | * Normally, @bdev should equal what's returned from bdget_disk() | |
837 | * if partno is 0; however, some drivers (floppy) use multiple | |
838 | * bdev's for the same physical device and @bdev may be one of the | |
839 | * aliases. Keep @bdev if partno is 0. This means claimer | |
840 | * tracking is broken for those devices but it has always been that | |
841 | * way. | |
842 | */ | |
843 | if (partno) | |
844 | whole = bdget_disk(disk, 0); | |
845 | else | |
846 | whole = bdgrab(bdev); | |
847 | ||
cf342570 | 848 | module_put(disk->fops->owner); |
6b4517a7 TH |
849 | put_disk(disk); |
850 | if (!whole) | |
851 | return ERR_PTR(-ENOMEM); | |
852 | ||
853 | /* prepare to claim, if successful, mark claiming in progress */ | |
854 | spin_lock(&bdev_lock); | |
855 | ||
856 | err = bd_prepare_to_claim(bdev, whole, holder); | |
857 | if (err == 0) { | |
858 | whole->bd_claiming = holder; | |
859 | spin_unlock(&bdev_lock); | |
860 | return whole; | |
861 | } else { | |
862 | spin_unlock(&bdev_lock); | |
863 | bdput(whole); | |
864 | return ERR_PTR(err); | |
865 | } | |
866 | } | |
867 | ||
641dc636 | 868 | #ifdef CONFIG_SYSFS |
49731baa TH |
869 | struct bd_holder_disk { |
870 | struct list_head list; | |
871 | struct gendisk *disk; | |
872 | int refcnt; | |
873 | }; | |
874 | ||
875 | static struct bd_holder_disk *bd_find_holder_disk(struct block_device *bdev, | |
876 | struct gendisk *disk) | |
877 | { | |
878 | struct bd_holder_disk *holder; | |
879 | ||
880 | list_for_each_entry(holder, &bdev->bd_holder_disks, list) | |
881 | if (holder->disk == disk) | |
882 | return holder; | |
883 | return NULL; | |
884 | } | |
885 | ||
4d7dd8fd | 886 | static int add_symlink(struct kobject *from, struct kobject *to) |
641dc636 | 887 | { |
4d7dd8fd | 888 | return sysfs_create_link(from, to, kobject_name(to)); |
641dc636 JN |
889 | } |
890 | ||
891 | static void del_symlink(struct kobject *from, struct kobject *to) | |
892 | { | |
641dc636 JN |
893 | sysfs_remove_link(from, kobject_name(to)); |
894 | } | |
895 | ||
df6c0cd9 | 896 | /** |
e09b457b TH |
897 | * bd_link_disk_holder - create symlinks between holding disk and slave bdev |
898 | * @bdev: the claimed slave bdev | |
899 | * @disk: the holding disk | |
df6c0cd9 | 900 | * |
49731baa TH |
901 | * DON'T USE THIS UNLESS YOU'RE ALREADY USING IT. |
902 | * | |
e09b457b | 903 | * This functions creates the following sysfs symlinks. |
641dc636 | 904 | * |
e09b457b TH |
905 | * - from "slaves" directory of the holder @disk to the claimed @bdev |
906 | * - from "holders" directory of the @bdev to the holder @disk | |
641dc636 | 907 | * |
e09b457b TH |
908 | * For example, if /dev/dm-0 maps to /dev/sda and disk for dm-0 is |
909 | * passed to bd_link_disk_holder(), then: | |
641dc636 | 910 | * |
e09b457b TH |
911 | * /sys/block/dm-0/slaves/sda --> /sys/block/sda |
912 | * /sys/block/sda/holders/dm-0 --> /sys/block/dm-0 | |
641dc636 | 913 | * |
e09b457b TH |
914 | * The caller must have claimed @bdev before calling this function and |
915 | * ensure that both @bdev and @disk are valid during the creation and | |
916 | * lifetime of these symlinks. | |
641dc636 | 917 | * |
e09b457b TH |
918 | * CONTEXT: |
919 | * Might sleep. | |
641dc636 | 920 | * |
e09b457b TH |
921 | * RETURNS: |
922 | * 0 on success, -errno on failure. | |
641dc636 | 923 | */ |
e09b457b | 924 | int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk) |
641dc636 | 925 | { |
49731baa | 926 | struct bd_holder_disk *holder; |
e09b457b | 927 | int ret = 0; |
641dc636 | 928 | |
2e7b651d | 929 | mutex_lock(&bdev->bd_mutex); |
df6c0cd9 | 930 | |
49731baa | 931 | WARN_ON_ONCE(!bdev->bd_holder); |
4e91672c | 932 | |
e09b457b TH |
933 | /* FIXME: remove the following once add_disk() handles errors */ |
934 | if (WARN_ON(!disk->slave_dir || !bdev->bd_part->holder_dir)) | |
935 | goto out_unlock; | |
4e91672c | 936 | |
49731baa TH |
937 | holder = bd_find_holder_disk(bdev, disk); |
938 | if (holder) { | |
939 | holder->refcnt++; | |
e09b457b | 940 | goto out_unlock; |
49731baa | 941 | } |
641dc636 | 942 | |
49731baa TH |
943 | holder = kzalloc(sizeof(*holder), GFP_KERNEL); |
944 | if (!holder) { | |
945 | ret = -ENOMEM; | |
e09b457b TH |
946 | goto out_unlock; |
947 | } | |
641dc636 | 948 | |
49731baa TH |
949 | INIT_LIST_HEAD(&holder->list); |
950 | holder->disk = disk; | |
951 | holder->refcnt = 1; | |
952 | ||
953 | ret = add_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj); | |
954 | if (ret) | |
955 | goto out_free; | |
956 | ||
957 | ret = add_symlink(bdev->bd_part->holder_dir, &disk_to_dev(disk)->kobj); | |
958 | if (ret) | |
959 | goto out_del; | |
e7407d16 TH |
960 | /* |
961 | * bdev could be deleted beneath us which would implicitly destroy | |
962 | * the holder directory. Hold on to it. | |
963 | */ | |
964 | kobject_get(bdev->bd_part->holder_dir); | |
49731baa TH |
965 | |
966 | list_add(&holder->list, &bdev->bd_holder_disks); | |
967 | goto out_unlock; | |
968 | ||
969 | out_del: | |
970 | del_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj); | |
971 | out_free: | |
972 | kfree(holder); | |
e09b457b | 973 | out_unlock: |
b4cf1b72 | 974 | mutex_unlock(&bdev->bd_mutex); |
e09b457b | 975 | return ret; |
641dc636 | 976 | } |
e09b457b | 977 | EXPORT_SYMBOL_GPL(bd_link_disk_holder); |
641dc636 | 978 | |
49731baa TH |
979 | /** |
980 | * bd_unlink_disk_holder - destroy symlinks created by bd_link_disk_holder() | |
981 | * @bdev: the calimed slave bdev | |
982 | * @disk: the holding disk | |
983 | * | |
984 | * DON'T USE THIS UNLESS YOU'RE ALREADY USING IT. | |
985 | * | |
986 | * CONTEXT: | |
987 | * Might sleep. | |
988 | */ | |
989 | void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk) | |
641dc636 | 990 | { |
49731baa | 991 | struct bd_holder_disk *holder; |
641dc636 | 992 | |
49731baa | 993 | mutex_lock(&bdev->bd_mutex); |
641dc636 | 994 | |
49731baa TH |
995 | holder = bd_find_holder_disk(bdev, disk); |
996 | ||
997 | if (!WARN_ON_ONCE(holder == NULL) && !--holder->refcnt) { | |
998 | del_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj); | |
999 | del_symlink(bdev->bd_part->holder_dir, | |
1000 | &disk_to_dev(disk)->kobj); | |
e7407d16 | 1001 | kobject_put(bdev->bd_part->holder_dir); |
49731baa TH |
1002 | list_del_init(&holder->list); |
1003 | kfree(holder); | |
1004 | } | |
1005 | ||
1006 | mutex_unlock(&bdev->bd_mutex); | |
1da177e4 | 1007 | } |
49731baa | 1008 | EXPORT_SYMBOL_GPL(bd_unlink_disk_holder); |
641dc636 | 1009 | #endif |
1da177e4 | 1010 | |
56ade44b AP |
1011 | /** |
1012 | * flush_disk - invalidates all buffer-cache entries on a disk | |
1013 | * | |
1014 | * @bdev: struct block device to be flushed | |
e6eb5ce1 | 1015 | * @kill_dirty: flag to guide handling of dirty inodes |
56ade44b AP |
1016 | * |
1017 | * Invalidates all buffer-cache entries on a disk. It should be called | |
1018 | * when a disk has been changed -- either by a media change or online | |
1019 | * resize. | |
1020 | */ | |
93b270f7 | 1021 | static void flush_disk(struct block_device *bdev, bool kill_dirty) |
56ade44b | 1022 | { |
93b270f7 | 1023 | if (__invalidate_device(bdev, kill_dirty)) { |
56ade44b AP |
1024 | char name[BDEVNAME_SIZE] = ""; |
1025 | ||
1026 | if (bdev->bd_disk) | |
1027 | disk_name(bdev->bd_disk, 0, name); | |
1028 | printk(KERN_WARNING "VFS: busy inodes on changed media or " | |
1029 | "resized disk %s\n", name); | |
1030 | } | |
1031 | ||
1032 | if (!bdev->bd_disk) | |
1033 | return; | |
d27769ec | 1034 | if (disk_part_scan_enabled(bdev->bd_disk)) |
56ade44b AP |
1035 | bdev->bd_invalidated = 1; |
1036 | } | |
1037 | ||
c3279d14 | 1038 | /** |
57d1b536 | 1039 | * check_disk_size_change - checks for disk size change and adjusts bdev size. |
c3279d14 AP |
1040 | * @disk: struct gendisk to check |
1041 | * @bdev: struct bdev to adjust. | |
1042 | * | |
1043 | * This routine checks to see if the bdev size does not match the disk size | |
1044 | * and adjusts it if it differs. | |
1045 | */ | |
1046 | void check_disk_size_change(struct gendisk *disk, struct block_device *bdev) | |
1047 | { | |
1048 | loff_t disk_size, bdev_size; | |
1049 | ||
1050 | disk_size = (loff_t)get_capacity(disk) << 9; | |
1051 | bdev_size = i_size_read(bdev->bd_inode); | |
1052 | if (disk_size != bdev_size) { | |
1053 | char name[BDEVNAME_SIZE]; | |
1054 | ||
1055 | disk_name(disk, 0, name); | |
1056 | printk(KERN_INFO | |
1057 | "%s: detected capacity change from %lld to %lld\n", | |
1058 | name, bdev_size, disk_size); | |
1059 | i_size_write(bdev->bd_inode, disk_size); | |
93b270f7 | 1060 | flush_disk(bdev, false); |
c3279d14 AP |
1061 | } |
1062 | } | |
1063 | EXPORT_SYMBOL(check_disk_size_change); | |
1064 | ||
0c002c2f | 1065 | /** |
57d1b536 | 1066 | * revalidate_disk - wrapper for lower-level driver's revalidate_disk call-back |
0c002c2f AP |
1067 | * @disk: struct gendisk to be revalidated |
1068 | * | |
1069 | * This routine is a wrapper for lower-level driver's revalidate_disk | |
1070 | * call-backs. It is used to do common pre and post operations needed | |
1071 | * for all revalidate_disk operations. | |
1072 | */ | |
1073 | int revalidate_disk(struct gendisk *disk) | |
1074 | { | |
c3279d14 | 1075 | struct block_device *bdev; |
0c002c2f AP |
1076 | int ret = 0; |
1077 | ||
1078 | if (disk->fops->revalidate_disk) | |
1079 | ret = disk->fops->revalidate_disk(disk); | |
1080 | ||
c3279d14 AP |
1081 | bdev = bdget_disk(disk, 0); |
1082 | if (!bdev) | |
1083 | return ret; | |
1084 | ||
1085 | mutex_lock(&bdev->bd_mutex); | |
1086 | check_disk_size_change(disk, bdev); | |
7630b661 | 1087 | bdev->bd_invalidated = 0; |
c3279d14 AP |
1088 | mutex_unlock(&bdev->bd_mutex); |
1089 | bdput(bdev); | |
0c002c2f AP |
1090 | return ret; |
1091 | } | |
1092 | EXPORT_SYMBOL(revalidate_disk); | |
1093 | ||
1da177e4 LT |
1094 | /* |
1095 | * This routine checks whether a removable media has been changed, | |
1096 | * and invalidates all buffer-cache-entries in that case. This | |
1097 | * is a relatively slow routine, so we have to try to minimize using | |
1098 | * it. Thus it is called only upon a 'mount' or 'open'. This | |
1099 | * is the best way of combining speed and utility, I think. | |
1100 | * People changing diskettes in the middle of an operation deserve | |
1101 | * to lose :-) | |
1102 | */ | |
1103 | int check_disk_change(struct block_device *bdev) | |
1104 | { | |
1105 | struct gendisk *disk = bdev->bd_disk; | |
83d5cde4 | 1106 | const struct block_device_operations *bdops = disk->fops; |
77ea887e | 1107 | unsigned int events; |
1da177e4 | 1108 | |
77ea887e TH |
1109 | events = disk_clear_events(disk, DISK_EVENT_MEDIA_CHANGE | |
1110 | DISK_EVENT_EJECT_REQUEST); | |
1111 | if (!(events & DISK_EVENT_MEDIA_CHANGE)) | |
1da177e4 LT |
1112 | return 0; |
1113 | ||
93b270f7 | 1114 | flush_disk(bdev, true); |
1da177e4 LT |
1115 | if (bdops->revalidate_disk) |
1116 | bdops->revalidate_disk(bdev->bd_disk); | |
1da177e4 LT |
1117 | return 1; |
1118 | } | |
1119 | ||
1120 | EXPORT_SYMBOL(check_disk_change); | |
1121 | ||
1122 | void bd_set_size(struct block_device *bdev, loff_t size) | |
1123 | { | |
e1defc4f | 1124 | unsigned bsize = bdev_logical_block_size(bdev); |
1da177e4 | 1125 | |
d646a02a GC |
1126 | mutex_lock(&bdev->bd_inode->i_mutex); |
1127 | i_size_write(bdev->bd_inode, size); | |
1128 | mutex_unlock(&bdev->bd_inode->i_mutex); | |
1da177e4 LT |
1129 | while (bsize < PAGE_CACHE_SIZE) { |
1130 | if (size & bsize) | |
1131 | break; | |
1132 | bsize <<= 1; | |
1133 | } | |
1134 | bdev->bd_block_size = bsize; | |
1135 | bdev->bd_inode->i_blkbits = blksize_bits(bsize); | |
1136 | } | |
1137 | EXPORT_SYMBOL(bd_set_size); | |
1138 | ||
4385bab1 | 1139 | static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part); |
37be4124 | 1140 | |
6d740cd5 PZ |
1141 | /* |
1142 | * bd_mutex locking: | |
1143 | * | |
1144 | * mutex_lock(part->bd_mutex) | |
1145 | * mutex_lock_nested(whole->bd_mutex, 1) | |
1146 | */ | |
1147 | ||
572c4892 | 1148 | static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part) |
1da177e4 | 1149 | { |
1da177e4 | 1150 | struct gendisk *disk; |
523e1d39 | 1151 | struct module *owner; |
7db9cfd3 | 1152 | int ret; |
cf771cb5 | 1153 | int partno; |
fe6e9c1f AV |
1154 | int perm = 0; |
1155 | ||
572c4892 | 1156 | if (mode & FMODE_READ) |
fe6e9c1f | 1157 | perm |= MAY_READ; |
572c4892 | 1158 | if (mode & FMODE_WRITE) |
fe6e9c1f AV |
1159 | perm |= MAY_WRITE; |
1160 | /* | |
1161 | * hooks: /n/, see "layering violations". | |
1162 | */ | |
b7300b78 CW |
1163 | if (!for_part) { |
1164 | ret = devcgroup_inode_permission(bdev->bd_inode, perm); | |
1165 | if (ret != 0) { | |
1166 | bdput(bdev); | |
1167 | return ret; | |
1168 | } | |
82666020 | 1169 | } |
7db9cfd3 | 1170 | |
d3374825 | 1171 | restart: |
0762b8bd | 1172 | |
89f97496 | 1173 | ret = -ENXIO; |
cf771cb5 | 1174 | disk = get_gendisk(bdev->bd_dev, &partno); |
0762b8bd | 1175 | if (!disk) |
6e9624b8 | 1176 | goto out; |
523e1d39 | 1177 | owner = disk->fops->owner; |
1da177e4 | 1178 | |
69e02c59 | 1179 | disk_block_events(disk); |
6796bf54 | 1180 | mutex_lock_nested(&bdev->bd_mutex, for_part); |
1da177e4 LT |
1181 | if (!bdev->bd_openers) { |
1182 | bdev->bd_disk = disk; | |
87192a2a | 1183 | bdev->bd_queue = disk->queue; |
1da177e4 | 1184 | bdev->bd_contains = bdev; |
bbab37dd | 1185 | bdev->bd_inode->i_flags = disk->fops->direct_access ? S_DAX : 0; |
cf771cb5 | 1186 | if (!partno) { |
89f97496 TH |
1187 | ret = -ENXIO; |
1188 | bdev->bd_part = disk_get_part(disk, partno); | |
1189 | if (!bdev->bd_part) | |
1190 | goto out_clear; | |
1191 | ||
1196f8b8 | 1192 | ret = 0; |
1da177e4 | 1193 | if (disk->fops->open) { |
572c4892 | 1194 | ret = disk->fops->open(bdev, mode); |
d3374825 N |
1195 | if (ret == -ERESTARTSYS) { |
1196 | /* Lost a race with 'disk' being | |
1197 | * deleted, try again. | |
1198 | * See md.c | |
1199 | */ | |
1200 | disk_put_part(bdev->bd_part); | |
1201 | bdev->bd_part = NULL; | |
d3374825 | 1202 | bdev->bd_disk = NULL; |
87192a2a | 1203 | bdev->bd_queue = NULL; |
d3374825 | 1204 | mutex_unlock(&bdev->bd_mutex); |
69e02c59 | 1205 | disk_unblock_events(disk); |
69e02c59 | 1206 | put_disk(disk); |
523e1d39 | 1207 | module_put(owner); |
d3374825 N |
1208 | goto restart; |
1209 | } | |
1da177e4 | 1210 | } |
7e69723f | 1211 | |
b83ae6d4 | 1212 | if (!ret) |
7e69723f | 1213 | bd_set_size(bdev,(loff_t)get_capacity(disk)<<9); |
7e69723f | 1214 | |
1196f8b8 TH |
1215 | /* |
1216 | * If the device is invalidated, rescan partition | |
1217 | * if open succeeded or failed with -ENOMEDIUM. | |
1218 | * The latter is necessary to prevent ghost | |
1219 | * partitions on a removed medium. | |
1220 | */ | |
fe316bf2 JN |
1221 | if (bdev->bd_invalidated) { |
1222 | if (!ret) | |
1223 | rescan_partitions(disk, bdev); | |
1224 | else if (ret == -ENOMEDIUM) | |
1225 | invalidate_partitions(disk, bdev); | |
1226 | } | |
1196f8b8 TH |
1227 | if (ret) |
1228 | goto out_clear; | |
1da177e4 | 1229 | } else { |
1da177e4 LT |
1230 | struct block_device *whole; |
1231 | whole = bdget_disk(disk, 0); | |
1232 | ret = -ENOMEM; | |
1233 | if (!whole) | |
0762b8bd | 1234 | goto out_clear; |
37be4124 | 1235 | BUG_ON(for_part); |
572c4892 | 1236 | ret = __blkdev_get(whole, mode, 1); |
1da177e4 | 1237 | if (ret) |
0762b8bd | 1238 | goto out_clear; |
1da177e4 | 1239 | bdev->bd_contains = whole; |
89f97496 | 1240 | bdev->bd_part = disk_get_part(disk, partno); |
e71bf0d0 | 1241 | if (!(disk->flags & GENHD_FL_UP) || |
89f97496 | 1242 | !bdev->bd_part || !bdev->bd_part->nr_sects) { |
1da177e4 | 1243 | ret = -ENXIO; |
0762b8bd | 1244 | goto out_clear; |
1da177e4 | 1245 | } |
89f97496 | 1246 | bd_set_size(bdev, (loff_t)bdev->bd_part->nr_sects << 9); |
1da177e4 LT |
1247 | } |
1248 | } else { | |
1da177e4 | 1249 | if (bdev->bd_contains == bdev) { |
1196f8b8 TH |
1250 | ret = 0; |
1251 | if (bdev->bd_disk->fops->open) | |
572c4892 | 1252 | ret = bdev->bd_disk->fops->open(bdev, mode); |
1196f8b8 | 1253 | /* the same as first opener case, read comment there */ |
fe316bf2 JN |
1254 | if (bdev->bd_invalidated) { |
1255 | if (!ret) | |
1256 | rescan_partitions(bdev->bd_disk, bdev); | |
1257 | else if (ret == -ENOMEDIUM) | |
1258 | invalidate_partitions(bdev->bd_disk, bdev); | |
1259 | } | |
1196f8b8 TH |
1260 | if (ret) |
1261 | goto out_unlock_bdev; | |
1da177e4 | 1262 | } |
69e02c59 | 1263 | /* only one opener holds refs to the module and disk */ |
69e02c59 | 1264 | put_disk(disk); |
523e1d39 | 1265 | module_put(owner); |
1da177e4 LT |
1266 | } |
1267 | bdev->bd_openers++; | |
37be4124 N |
1268 | if (for_part) |
1269 | bdev->bd_part_count++; | |
c039e313 | 1270 | mutex_unlock(&bdev->bd_mutex); |
69e02c59 | 1271 | disk_unblock_events(disk); |
1da177e4 LT |
1272 | return 0; |
1273 | ||
0762b8bd | 1274 | out_clear: |
89f97496 | 1275 | disk_put_part(bdev->bd_part); |
1da177e4 | 1276 | bdev->bd_disk = NULL; |
0762b8bd | 1277 | bdev->bd_part = NULL; |
87192a2a | 1278 | bdev->bd_queue = NULL; |
1da177e4 | 1279 | if (bdev != bdev->bd_contains) |
572c4892 | 1280 | __blkdev_put(bdev->bd_contains, mode, 1); |
1da177e4 | 1281 | bdev->bd_contains = NULL; |
0762b8bd | 1282 | out_unlock_bdev: |
c039e313 | 1283 | mutex_unlock(&bdev->bd_mutex); |
69e02c59 | 1284 | disk_unblock_events(disk); |
0762b8bd | 1285 | put_disk(disk); |
523e1d39 | 1286 | module_put(owner); |
4345caba | 1287 | out: |
0762b8bd TH |
1288 | bdput(bdev); |
1289 | ||
1da177e4 LT |
1290 | return ret; |
1291 | } | |
1292 | ||
d4d77629 TH |
1293 | /** |
1294 | * blkdev_get - open a block device | |
1295 | * @bdev: block_device to open | |
1296 | * @mode: FMODE_* mask | |
1297 | * @holder: exclusive holder identifier | |
1298 | * | |
1299 | * Open @bdev with @mode. If @mode includes %FMODE_EXCL, @bdev is | |
1300 | * open with exclusive access. Specifying %FMODE_EXCL with %NULL | |
1301 | * @holder is invalid. Exclusive opens may nest for the same @holder. | |
1302 | * | |
1303 | * On success, the reference count of @bdev is unchanged. On failure, | |
1304 | * @bdev is put. | |
1305 | * | |
1306 | * CONTEXT: | |
1307 | * Might sleep. | |
1308 | * | |
1309 | * RETURNS: | |
1310 | * 0 on success, -errno on failure. | |
1311 | */ | |
e525fd89 | 1312 | int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder) |
1da177e4 | 1313 | { |
e525fd89 TH |
1314 | struct block_device *whole = NULL; |
1315 | int res; | |
1316 | ||
1317 | WARN_ON_ONCE((mode & FMODE_EXCL) && !holder); | |
1318 | ||
1319 | if ((mode & FMODE_EXCL) && holder) { | |
1320 | whole = bd_start_claiming(bdev, holder); | |
1321 | if (IS_ERR(whole)) { | |
1322 | bdput(bdev); | |
1323 | return PTR_ERR(whole); | |
1324 | } | |
1325 | } | |
1326 | ||
1327 | res = __blkdev_get(bdev, mode, 0); | |
1328 | ||
1329 | if (whole) { | |
d4dc210f TH |
1330 | struct gendisk *disk = whole->bd_disk; |
1331 | ||
6a027eff | 1332 | /* finish claiming */ |
77ea887e | 1333 | mutex_lock(&bdev->bd_mutex); |
6a027eff TH |
1334 | spin_lock(&bdev_lock); |
1335 | ||
77ea887e | 1336 | if (!res) { |
6a027eff TH |
1337 | BUG_ON(!bd_may_claim(bdev, whole, holder)); |
1338 | /* | |
1339 | * Note that for a whole device bd_holders | |
1340 | * will be incremented twice, and bd_holder | |
1341 | * will be set to bd_may_claim before being | |
1342 | * set to holder | |
1343 | */ | |
1344 | whole->bd_holders++; | |
1345 | whole->bd_holder = bd_may_claim; | |
1346 | bdev->bd_holders++; | |
1347 | bdev->bd_holder = holder; | |
1348 | } | |
1349 | ||
1350 | /* tell others that we're done */ | |
1351 | BUG_ON(whole->bd_claiming != holder); | |
1352 | whole->bd_claiming = NULL; | |
1353 | wake_up_bit(&whole->bd_claiming, 0); | |
1354 | ||
1355 | spin_unlock(&bdev_lock); | |
77ea887e TH |
1356 | |
1357 | /* | |
d4dc210f TH |
1358 | * Block event polling for write claims if requested. Any |
1359 | * write holder makes the write_holder state stick until | |
1360 | * all are released. This is good enough and tracking | |
1361 | * individual writeable reference is too fragile given the | |
1362 | * way @mode is used in blkdev_get/put(). | |
77ea887e | 1363 | */ |
4c49ff3f TH |
1364 | if (!res && (mode & FMODE_WRITE) && !bdev->bd_write_holder && |
1365 | (disk->flags & GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE)) { | |
77ea887e | 1366 | bdev->bd_write_holder = true; |
d4dc210f | 1367 | disk_block_events(disk); |
77ea887e TH |
1368 | } |
1369 | ||
1370 | mutex_unlock(&bdev->bd_mutex); | |
6a027eff | 1371 | bdput(whole); |
e525fd89 TH |
1372 | } |
1373 | ||
1374 | return res; | |
37be4124 | 1375 | } |
1da177e4 LT |
1376 | EXPORT_SYMBOL(blkdev_get); |
1377 | ||
d4d77629 TH |
1378 | /** |
1379 | * blkdev_get_by_path - open a block device by name | |
1380 | * @path: path to the block device to open | |
1381 | * @mode: FMODE_* mask | |
1382 | * @holder: exclusive holder identifier | |
1383 | * | |
1384 | * Open the blockdevice described by the device file at @path. @mode | |
1385 | * and @holder are identical to blkdev_get(). | |
1386 | * | |
1387 | * On success, the returned block_device has reference count of one. | |
1388 | * | |
1389 | * CONTEXT: | |
1390 | * Might sleep. | |
1391 | * | |
1392 | * RETURNS: | |
1393 | * Pointer to block_device on success, ERR_PTR(-errno) on failure. | |
1394 | */ | |
1395 | struct block_device *blkdev_get_by_path(const char *path, fmode_t mode, | |
1396 | void *holder) | |
1397 | { | |
1398 | struct block_device *bdev; | |
1399 | int err; | |
1400 | ||
1401 | bdev = lookup_bdev(path); | |
1402 | if (IS_ERR(bdev)) | |
1403 | return bdev; | |
1404 | ||
1405 | err = blkdev_get(bdev, mode, holder); | |
1406 | if (err) | |
1407 | return ERR_PTR(err); | |
1408 | ||
e51900f7 CE |
1409 | if ((mode & FMODE_WRITE) && bdev_read_only(bdev)) { |
1410 | blkdev_put(bdev, mode); | |
1411 | return ERR_PTR(-EACCES); | |
1412 | } | |
1413 | ||
d4d77629 TH |
1414 | return bdev; |
1415 | } | |
1416 | EXPORT_SYMBOL(blkdev_get_by_path); | |
1417 | ||
1418 | /** | |
1419 | * blkdev_get_by_dev - open a block device by device number | |
1420 | * @dev: device number of block device to open | |
1421 | * @mode: FMODE_* mask | |
1422 | * @holder: exclusive holder identifier | |
1423 | * | |
1424 | * Open the blockdevice described by device number @dev. @mode and | |
1425 | * @holder are identical to blkdev_get(). | |
1426 | * | |
1427 | * Use it ONLY if you really do not have anything better - i.e. when | |
1428 | * you are behind a truly sucky interface and all you are given is a | |
1429 | * device number. _Never_ to be used for internal purposes. If you | |
1430 | * ever need it - reconsider your API. | |
1431 | * | |
1432 | * On success, the returned block_device has reference count of one. | |
1433 | * | |
1434 | * CONTEXT: | |
1435 | * Might sleep. | |
1436 | * | |
1437 | * RETURNS: | |
1438 | * Pointer to block_device on success, ERR_PTR(-errno) on failure. | |
1439 | */ | |
1440 | struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder) | |
1441 | { | |
1442 | struct block_device *bdev; | |
1443 | int err; | |
1444 | ||
1445 | bdev = bdget(dev); | |
1446 | if (!bdev) | |
1447 | return ERR_PTR(-ENOMEM); | |
1448 | ||
1449 | err = blkdev_get(bdev, mode, holder); | |
1450 | if (err) | |
1451 | return ERR_PTR(err); | |
1452 | ||
1453 | return bdev; | |
1454 | } | |
1455 | EXPORT_SYMBOL(blkdev_get_by_dev); | |
1456 | ||
1da177e4 LT |
1457 | static int blkdev_open(struct inode * inode, struct file * filp) |
1458 | { | |
1459 | struct block_device *bdev; | |
1da177e4 LT |
1460 | |
1461 | /* | |
1462 | * Preserve backwards compatibility and allow large file access | |
1463 | * even if userspace doesn't ask for it explicitly. Some mkfs | |
1464 | * binary needs it. We might want to drop this workaround | |
1465 | * during an unstable branch. | |
1466 | */ | |
1467 | filp->f_flags |= O_LARGEFILE; | |
1468 | ||
572c4892 AV |
1469 | if (filp->f_flags & O_NDELAY) |
1470 | filp->f_mode |= FMODE_NDELAY; | |
1471 | if (filp->f_flags & O_EXCL) | |
1472 | filp->f_mode |= FMODE_EXCL; | |
1473 | if ((filp->f_flags & O_ACCMODE) == 3) | |
1474 | filp->f_mode |= FMODE_WRITE_IOCTL; | |
1475 | ||
1da177e4 | 1476 | bdev = bd_acquire(inode); |
6a2aae06 PE |
1477 | if (bdev == NULL) |
1478 | return -ENOMEM; | |
1da177e4 | 1479 | |
572c4892 AV |
1480 | filp->f_mapping = bdev->bd_inode->i_mapping; |
1481 | ||
e525fd89 | 1482 | return blkdev_get(bdev, filp->f_mode, filp); |
1da177e4 LT |
1483 | } |
1484 | ||
4385bab1 | 1485 | static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part) |
2e7b651d | 1486 | { |
2e7b651d | 1487 | struct gendisk *disk = bdev->bd_disk; |
37be4124 | 1488 | struct block_device *victim = NULL; |
2e7b651d | 1489 | |
6796bf54 | 1490 | mutex_lock_nested(&bdev->bd_mutex, for_part); |
37be4124 N |
1491 | if (for_part) |
1492 | bdev->bd_part_count--; | |
1493 | ||
2e7b651d | 1494 | if (!--bdev->bd_openers) { |
6a027eff | 1495 | WARN_ON_ONCE(bdev->bd_holders); |
2e7b651d PZ |
1496 | sync_blockdev(bdev); |
1497 | kill_bdev(bdev); | |
564f00f6 CH |
1498 | /* |
1499 | * ->release can cause the queue to disappear, so flush all | |
1500 | * dirty data before. | |
94007751 | 1501 | */ |
564f00f6 | 1502 | bdev_write_inode(bdev->bd_inode); |
2e7b651d PZ |
1503 | } |
1504 | if (bdev->bd_contains == bdev) { | |
1505 | if (disk->fops->release) | |
db2a144b | 1506 | disk->fops->release(disk, mode); |
2e7b651d PZ |
1507 | } |
1508 | if (!bdev->bd_openers) { | |
1509 | struct module *owner = disk->fops->owner; | |
1510 | ||
0762b8bd TH |
1511 | disk_put_part(bdev->bd_part); |
1512 | bdev->bd_part = NULL; | |
2e7b651d | 1513 | bdev->bd_disk = NULL; |
37be4124 N |
1514 | if (bdev != bdev->bd_contains) |
1515 | victim = bdev->bd_contains; | |
2e7b651d | 1516 | bdev->bd_contains = NULL; |
523e1d39 TH |
1517 | |
1518 | put_disk(disk); | |
1519 | module_put(owner); | |
2e7b651d | 1520 | } |
2e7b651d PZ |
1521 | mutex_unlock(&bdev->bd_mutex); |
1522 | bdput(bdev); | |
37be4124 | 1523 | if (victim) |
9a1c3542 | 1524 | __blkdev_put(victim, mode, 1); |
2e7b651d PZ |
1525 | } |
1526 | ||
4385bab1 | 1527 | void blkdev_put(struct block_device *bdev, fmode_t mode) |
37be4124 | 1528 | { |
85ef06d1 TH |
1529 | mutex_lock(&bdev->bd_mutex); |
1530 | ||
e525fd89 | 1531 | if (mode & FMODE_EXCL) { |
6a027eff TH |
1532 | bool bdev_free; |
1533 | ||
1534 | /* | |
1535 | * Release a claim on the device. The holder fields | |
1536 | * are protected with bdev_lock. bd_mutex is to | |
1537 | * synchronize disk_holder unlinking. | |
1538 | */ | |
6a027eff TH |
1539 | spin_lock(&bdev_lock); |
1540 | ||
1541 | WARN_ON_ONCE(--bdev->bd_holders < 0); | |
1542 | WARN_ON_ONCE(--bdev->bd_contains->bd_holders < 0); | |
1543 | ||
1544 | /* bd_contains might point to self, check in a separate step */ | |
1545 | if ((bdev_free = !bdev->bd_holders)) | |
1546 | bdev->bd_holder = NULL; | |
1547 | if (!bdev->bd_contains->bd_holders) | |
1548 | bdev->bd_contains->bd_holder = NULL; | |
1549 | ||
1550 | spin_unlock(&bdev_lock); | |
1551 | ||
77ea887e TH |
1552 | /* |
1553 | * If this was the last claim, remove holder link and | |
1554 | * unblock evpoll if it was a write holder. | |
1555 | */ | |
85ef06d1 TH |
1556 | if (bdev_free && bdev->bd_write_holder) { |
1557 | disk_unblock_events(bdev->bd_disk); | |
1558 | bdev->bd_write_holder = false; | |
77ea887e | 1559 | } |
6936217c | 1560 | } |
77ea887e | 1561 | |
85ef06d1 TH |
1562 | /* |
1563 | * Trigger event checking and tell drivers to flush MEDIA_CHANGE | |
1564 | * event. This is to ensure detection of media removal commanded | |
1565 | * from userland - e.g. eject(1). | |
1566 | */ | |
1567 | disk_flush_events(bdev->bd_disk, DISK_EVENT_MEDIA_CHANGE); | |
1568 | ||
1569 | mutex_unlock(&bdev->bd_mutex); | |
1570 | ||
4385bab1 | 1571 | __blkdev_put(bdev, mode, 0); |
37be4124 | 1572 | } |
2e7b651d PZ |
1573 | EXPORT_SYMBOL(blkdev_put); |
1574 | ||
1da177e4 LT |
1575 | static int blkdev_close(struct inode * inode, struct file * filp) |
1576 | { | |
1577 | struct block_device *bdev = I_BDEV(filp->f_mapping->host); | |
4385bab1 AV |
1578 | blkdev_put(bdev, filp->f_mode); |
1579 | return 0; | |
1da177e4 LT |
1580 | } |
1581 | ||
bb93e3a5 | 1582 | static long block_ioctl(struct file *file, unsigned cmd, unsigned long arg) |
1da177e4 | 1583 | { |
56b26add AV |
1584 | struct block_device *bdev = I_BDEV(file->f_mapping->host); |
1585 | fmode_t mode = file->f_mode; | |
fd4ce1ac CH |
1586 | |
1587 | /* | |
1588 | * O_NDELAY can be altered using fcntl(.., F_SETFL, ..), so we have | |
1589 | * to updated it before every ioctl. | |
1590 | */ | |
56b26add | 1591 | if (file->f_flags & O_NDELAY) |
fd4ce1ac CH |
1592 | mode |= FMODE_NDELAY; |
1593 | else | |
1594 | mode &= ~FMODE_NDELAY; | |
1595 | ||
56b26add | 1596 | return blkdev_ioctl(bdev, mode, cmd, arg); |
1da177e4 LT |
1597 | } |
1598 | ||
eef99380 CH |
1599 | /* |
1600 | * Write data to the block device. Only intended for the block device itself | |
1601 | * and the raw driver which basically is a fake block device. | |
1602 | * | |
1603 | * Does not take i_mutex for the write and thus is not for general purpose | |
1604 | * use. | |
1605 | */ | |
1456c0a8 | 1606 | ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from) |
eef99380 CH |
1607 | { |
1608 | struct file *file = iocb->ki_filp; | |
7ec7b94a AV |
1609 | struct inode *bd_inode = file->f_mapping->host; |
1610 | loff_t size = i_size_read(bd_inode); | |
53362a05 | 1611 | struct blk_plug plug; |
eef99380 | 1612 | ssize_t ret; |
5f380c7f | 1613 | |
7ec7b94a AV |
1614 | if (bdev_read_only(I_BDEV(bd_inode))) |
1615 | return -EPERM; | |
5f380c7f | 1616 | |
7ec7b94a | 1617 | if (!iov_iter_count(from)) |
5f380c7f AV |
1618 | return 0; |
1619 | ||
7ec7b94a AV |
1620 | if (iocb->ki_pos >= size) |
1621 | return -ENOSPC; | |
1622 | ||
1623 | iov_iter_truncate(from, size - iocb->ki_pos); | |
eef99380 | 1624 | |
53362a05 | 1625 | blk_start_plug(&plug); |
1456c0a8 | 1626 | ret = __generic_file_write_iter(iocb, from); |
02afc27f | 1627 | if (ret > 0) { |
eef99380 | 1628 | ssize_t err; |
1456c0a8 | 1629 | err = generic_write_sync(file, iocb->ki_pos - ret, ret); |
45d4f855 | 1630 | if (err < 0) |
eef99380 CH |
1631 | ret = err; |
1632 | } | |
53362a05 | 1633 | blk_finish_plug(&plug); |
eef99380 CH |
1634 | return ret; |
1635 | } | |
1456c0a8 | 1636 | EXPORT_SYMBOL_GPL(blkdev_write_iter); |
eef99380 | 1637 | |
b2de525f | 1638 | ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to) |
684c9aae LT |
1639 | { |
1640 | struct file *file = iocb->ki_filp; | |
1641 | struct inode *bd_inode = file->f_mapping->host; | |
1642 | loff_t size = i_size_read(bd_inode); | |
a886038b | 1643 | loff_t pos = iocb->ki_pos; |
684c9aae LT |
1644 | |
1645 | if (pos >= size) | |
1646 | return 0; | |
1647 | ||
1648 | size -= pos; | |
a886038b AV |
1649 | iov_iter_truncate(to, size); |
1650 | return generic_file_read_iter(iocb, to); | |
684c9aae | 1651 | } |
b2de525f | 1652 | EXPORT_SYMBOL_GPL(blkdev_read_iter); |
684c9aae | 1653 | |
87d8fe1e TT |
1654 | /* |
1655 | * Try to release a page associated with block device when the system | |
1656 | * is under memory pressure. | |
1657 | */ | |
1658 | static int blkdev_releasepage(struct page *page, gfp_t wait) | |
1659 | { | |
1660 | struct super_block *super = BDEV_I(page->mapping->host)->bdev.bd_super; | |
1661 | ||
1662 | if (super && super->s_op->bdev_try_to_free_page) | |
1663 | return super->s_op->bdev_try_to_free_page(super, page, wait); | |
1664 | ||
1665 | return try_to_free_buffers(page); | |
1666 | } | |
1667 | ||
4c54ac62 | 1668 | static const struct address_space_operations def_blk_aops = { |
1da177e4 | 1669 | .readpage = blkdev_readpage, |
447f05bb | 1670 | .readpages = blkdev_readpages, |
1da177e4 | 1671 | .writepage = blkdev_writepage, |
6272b5a5 NP |
1672 | .write_begin = blkdev_write_begin, |
1673 | .write_end = blkdev_write_end, | |
1da177e4 | 1674 | .writepages = generic_writepages, |
87d8fe1e | 1675 | .releasepage = blkdev_releasepage, |
1da177e4 | 1676 | .direct_IO = blkdev_direct_IO, |
b4597226 | 1677 | .is_dirty_writeback = buffer_check_dirty_writeback, |
1da177e4 LT |
1678 | }; |
1679 | ||
4b6f5d20 | 1680 | const struct file_operations def_blk_fops = { |
1da177e4 LT |
1681 | .open = blkdev_open, |
1682 | .release = blkdev_close, | |
1683 | .llseek = block_llseek, | |
a886038b | 1684 | .read_iter = blkdev_read_iter, |
1456c0a8 | 1685 | .write_iter = blkdev_write_iter, |
1e8b3332 | 1686 | .mmap = generic_file_mmap, |
b1dd3b28 | 1687 | .fsync = blkdev_fsync, |
bb93e3a5 | 1688 | .unlocked_ioctl = block_ioctl, |
1da177e4 LT |
1689 | #ifdef CONFIG_COMPAT |
1690 | .compat_ioctl = compat_blkdev_ioctl, | |
1691 | #endif | |
1e8b3332 | 1692 | .splice_read = generic_file_splice_read, |
8d020765 | 1693 | .splice_write = iter_file_splice_write, |
1da177e4 LT |
1694 | }; |
1695 | ||
1696 | int ioctl_by_bdev(struct block_device *bdev, unsigned cmd, unsigned long arg) | |
1697 | { | |
1698 | int res; | |
1699 | mm_segment_t old_fs = get_fs(); | |
1700 | set_fs(KERNEL_DS); | |
56b26add | 1701 | res = blkdev_ioctl(bdev, 0, cmd, arg); |
1da177e4 LT |
1702 | set_fs(old_fs); |
1703 | return res; | |
1704 | } | |
1705 | ||
1706 | EXPORT_SYMBOL(ioctl_by_bdev); | |
1707 | ||
1708 | /** | |
1709 | * lookup_bdev - lookup a struct block_device by name | |
94e2959e | 1710 | * @pathname: special file representing the block device |
1da177e4 | 1711 | * |
57d1b536 | 1712 | * Get a reference to the blockdevice at @pathname in the current |
1da177e4 LT |
1713 | * namespace if possible and return it. Return ERR_PTR(error) |
1714 | * otherwise. | |
1715 | */ | |
421748ec | 1716 | struct block_device *lookup_bdev(const char *pathname) |
1da177e4 LT |
1717 | { |
1718 | struct block_device *bdev; | |
1719 | struct inode *inode; | |
421748ec | 1720 | struct path path; |
1da177e4 LT |
1721 | int error; |
1722 | ||
421748ec | 1723 | if (!pathname || !*pathname) |
1da177e4 LT |
1724 | return ERR_PTR(-EINVAL); |
1725 | ||
421748ec | 1726 | error = kern_path(pathname, LOOKUP_FOLLOW, &path); |
1da177e4 LT |
1727 | if (error) |
1728 | return ERR_PTR(error); | |
1729 | ||
bb668734 | 1730 | inode = d_backing_inode(path.dentry); |
1da177e4 LT |
1731 | error = -ENOTBLK; |
1732 | if (!S_ISBLK(inode->i_mode)) | |
1733 | goto fail; | |
1734 | error = -EACCES; | |
421748ec | 1735 | if (path.mnt->mnt_flags & MNT_NODEV) |
1da177e4 LT |
1736 | goto fail; |
1737 | error = -ENOMEM; | |
1738 | bdev = bd_acquire(inode); | |
1739 | if (!bdev) | |
1740 | goto fail; | |
1741 | out: | |
421748ec | 1742 | path_put(&path); |
1da177e4 LT |
1743 | return bdev; |
1744 | fail: | |
1745 | bdev = ERR_PTR(error); | |
1746 | goto out; | |
1747 | } | |
d5686b44 | 1748 | EXPORT_SYMBOL(lookup_bdev); |
1da177e4 | 1749 | |
93b270f7 | 1750 | int __invalidate_device(struct block_device *bdev, bool kill_dirty) |
b71e8a4c DH |
1751 | { |
1752 | struct super_block *sb = get_super(bdev); | |
1753 | int res = 0; | |
1754 | ||
1755 | if (sb) { | |
1756 | /* | |
1757 | * no need to lock the super, get_super holds the | |
1758 | * read mutex so the filesystem cannot go away | |
1759 | * under us (->put_super runs with the write lock | |
1760 | * hold). | |
1761 | */ | |
1762 | shrink_dcache_sb(sb); | |
93b270f7 | 1763 | res = invalidate_inodes(sb, kill_dirty); |
b71e8a4c DH |
1764 | drop_super(sb); |
1765 | } | |
f98393a6 | 1766 | invalidate_bdev(bdev); |
b71e8a4c DH |
1767 | return res; |
1768 | } | |
1769 | EXPORT_SYMBOL(__invalidate_device); | |
5c0d6b60 JK |
1770 | |
1771 | void iterate_bdevs(void (*func)(struct block_device *, void *), void *arg) | |
1772 | { | |
1773 | struct inode *inode, *old_inode = NULL; | |
1774 | ||
1775 | spin_lock(&inode_sb_list_lock); | |
1776 | list_for_each_entry(inode, &blockdev_superblock->s_inodes, i_sb_list) { | |
1777 | struct address_space *mapping = inode->i_mapping; | |
1778 | ||
1779 | spin_lock(&inode->i_lock); | |
1780 | if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW) || | |
1781 | mapping->nrpages == 0) { | |
1782 | spin_unlock(&inode->i_lock); | |
1783 | continue; | |
1784 | } | |
1785 | __iget(inode); | |
1786 | spin_unlock(&inode->i_lock); | |
1787 | spin_unlock(&inode_sb_list_lock); | |
1788 | /* | |
1789 | * We hold a reference to 'inode' so it couldn't have been | |
1790 | * removed from s_inodes list while we dropped the | |
1791 | * inode_sb_list_lock. We cannot iput the inode now as we can | |
1792 | * be holding the last reference and we cannot iput it under | |
1793 | * inode_sb_list_lock. So we keep the reference and iput it | |
1794 | * later. | |
1795 | */ | |
1796 | iput(old_inode); | |
1797 | old_inode = inode; | |
1798 | ||
1799 | func(I_BDEV(inode), arg); | |
1800 | ||
1801 | spin_lock(&inode_sb_list_lock); | |
1802 | } | |
1803 | spin_unlock(&inode_sb_list_lock); | |
1804 | iput(old_inode); | |
1805 | } |