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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> | |
66114cad | 17 | #include <linux/backing-dev.h> |
1da177e4 LT |
18 | #include <linux/module.h> |
19 | #include <linux/blkpg.h> | |
b502bd11 | 20 | #include <linux/magic.h> |
1da177e4 | 21 | #include <linux/buffer_head.h> |
ff01bb48 | 22 | #include <linux/swap.h> |
585d3bc0 | 23 | #include <linux/pagevec.h> |
811d736f | 24 | #include <linux/writeback.h> |
1da177e4 LT |
25 | #include <linux/mpage.h> |
26 | #include <linux/mount.h> | |
27 | #include <linux/uio.h> | |
28 | #include <linux/namei.h> | |
1368c4f2 | 29 | #include <linux/log2.h> |
ff01bb48 | 30 | #include <linux/cleancache.h> |
c94c2acf | 31 | #include <linux/dax.h> |
1da177e4 | 32 | #include <asm/uaccess.h> |
07f3f05c | 33 | #include "internal.h" |
1da177e4 LT |
34 | |
35 | struct bdev_inode { | |
36 | struct block_device bdev; | |
37 | struct inode vfs_inode; | |
38 | }; | |
39 | ||
4c54ac62 AB |
40 | static const struct address_space_operations def_blk_aops; |
41 | ||
1da177e4 LT |
42 | static inline struct bdev_inode *BDEV_I(struct inode *inode) |
43 | { | |
44 | return container_of(inode, struct bdev_inode, vfs_inode); | |
45 | } | |
46 | ||
ff5053f6 | 47 | struct block_device *I_BDEV(struct inode *inode) |
1da177e4 LT |
48 | { |
49 | return &BDEV_I(inode)->bdev; | |
50 | } | |
1da177e4 LT |
51 | EXPORT_SYMBOL(I_BDEV); |
52 | ||
dbd3ca50 | 53 | static void bdev_write_inode(struct block_device *bdev) |
564f00f6 | 54 | { |
dbd3ca50 VG |
55 | struct inode *inode = bdev->bd_inode; |
56 | int ret; | |
57 | ||
564f00f6 CH |
58 | spin_lock(&inode->i_lock); |
59 | while (inode->i_state & I_DIRTY) { | |
60 | spin_unlock(&inode->i_lock); | |
dbd3ca50 VG |
61 | ret = write_inode_now(inode, true); |
62 | if (ret) { | |
63 | char name[BDEVNAME_SIZE]; | |
64 | pr_warn_ratelimited("VFS: Dirty inode writeback failed " | |
65 | "for block device %s (err=%d).\n", | |
66 | bdevname(bdev, name), ret); | |
67 | } | |
564f00f6 CH |
68 | spin_lock(&inode->i_lock); |
69 | } | |
70 | spin_unlock(&inode->i_lock); | |
71 | } | |
72 | ||
f9a14399 | 73 | /* Kill _all_ buffers and pagecache , dirty or not.. */ |
ff01bb48 | 74 | void kill_bdev(struct block_device *bdev) |
1da177e4 | 75 | { |
ff01bb48 AV |
76 | struct address_space *mapping = bdev->bd_inode->i_mapping; |
77 | ||
91b0abe3 | 78 | if (mapping->nrpages == 0 && mapping->nrshadows == 0) |
f9a14399 | 79 | return; |
ff01bb48 | 80 | |
f9a14399 | 81 | invalidate_bh_lrus(); |
ff01bb48 | 82 | truncate_inode_pages(mapping, 0); |
1da177e4 | 83 | } |
ff01bb48 AV |
84 | EXPORT_SYMBOL(kill_bdev); |
85 | ||
86 | /* Invalidate clean unused buffers and pagecache. */ | |
87 | void invalidate_bdev(struct block_device *bdev) | |
88 | { | |
89 | struct address_space *mapping = bdev->bd_inode->i_mapping; | |
90 | ||
ef59f128 AR |
91 | if (mapping->nrpages) { |
92 | invalidate_bh_lrus(); | |
93 | lru_add_drain_all(); /* make sure all lru add caches are flushed */ | |
94 | invalidate_mapping_pages(mapping, 0, -1); | |
95 | } | |
ff01bb48 AV |
96 | /* 99% of the time, we don't need to flush the cleancache on the bdev. |
97 | * But, for the strange corners, lets be cautious | |
98 | */ | |
3167760f | 99 | cleancache_invalidate_inode(mapping); |
ff01bb48 AV |
100 | } |
101 | EXPORT_SYMBOL(invalidate_bdev); | |
1da177e4 LT |
102 | |
103 | int set_blocksize(struct block_device *bdev, int size) | |
104 | { | |
105 | /* Size must be a power of two, and between 512 and PAGE_SIZE */ | |
1368c4f2 | 106 | if (size > PAGE_SIZE || size < 512 || !is_power_of_2(size)) |
1da177e4 LT |
107 | return -EINVAL; |
108 | ||
109 | /* Size cannot be smaller than the size supported by the device */ | |
e1defc4f | 110 | if (size < bdev_logical_block_size(bdev)) |
1da177e4 LT |
111 | return -EINVAL; |
112 | ||
113 | /* Don't change the size if it is same as current */ | |
114 | if (bdev->bd_block_size != size) { | |
115 | sync_blockdev(bdev); | |
116 | bdev->bd_block_size = size; | |
117 | bdev->bd_inode->i_blkbits = blksize_bits(size); | |
118 | kill_bdev(bdev); | |
119 | } | |
120 | return 0; | |
121 | } | |
122 | ||
123 | EXPORT_SYMBOL(set_blocksize); | |
124 | ||
125 | int sb_set_blocksize(struct super_block *sb, int size) | |
126 | { | |
1da177e4 LT |
127 | if (set_blocksize(sb->s_bdev, size)) |
128 | return 0; | |
129 | /* If we get here, we know size is power of two | |
130 | * and it's value is between 512 and PAGE_SIZE */ | |
131 | sb->s_blocksize = size; | |
38885bd4 | 132 | sb->s_blocksize_bits = blksize_bits(size); |
1da177e4 LT |
133 | return sb->s_blocksize; |
134 | } | |
135 | ||
136 | EXPORT_SYMBOL(sb_set_blocksize); | |
137 | ||
138 | int sb_min_blocksize(struct super_block *sb, int size) | |
139 | { | |
e1defc4f | 140 | int minsize = bdev_logical_block_size(sb->s_bdev); |
1da177e4 LT |
141 | if (size < minsize) |
142 | size = minsize; | |
143 | return sb_set_blocksize(sb, size); | |
144 | } | |
145 | ||
146 | EXPORT_SYMBOL(sb_min_blocksize); | |
147 | ||
148 | static int | |
149 | blkdev_get_block(struct inode *inode, sector_t iblock, | |
150 | struct buffer_head *bh, int create) | |
151 | { | |
1da177e4 LT |
152 | bh->b_bdev = I_BDEV(inode); |
153 | bh->b_blocknr = iblock; | |
154 | set_buffer_mapped(bh); | |
155 | return 0; | |
156 | } | |
157 | ||
b2e895db | 158 | static ssize_t |
22c6186e | 159 | blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, loff_t offset) |
b2e895db AM |
160 | { |
161 | struct file *file = iocb->ki_filp; | |
162 | struct inode *inode = file->f_mapping->host; | |
163 | ||
bbab37dd MW |
164 | if (IS_DAX(inode)) |
165 | return dax_do_io(iocb, inode, iter, offset, blkdev_get_block, | |
166 | NULL, DIO_SKIP_DIO_COUNT); | |
17f8c842 | 167 | return __blockdev_direct_IO(iocb, inode, I_BDEV(inode), iter, offset, |
fe0f07d0 JA |
168 | blkdev_get_block, NULL, NULL, |
169 | DIO_SKIP_DIO_COUNT); | |
b2e895db AM |
170 | } |
171 | ||
5cee5815 JK |
172 | int __sync_blockdev(struct block_device *bdev, int wait) |
173 | { | |
174 | if (!bdev) | |
175 | return 0; | |
176 | if (!wait) | |
177 | return filemap_flush(bdev->bd_inode->i_mapping); | |
178 | return filemap_write_and_wait(bdev->bd_inode->i_mapping); | |
179 | } | |
180 | ||
585d3bc0 NP |
181 | /* |
182 | * Write out and wait upon all the dirty data associated with a block | |
183 | * device via its mapping. Does not take the superblock lock. | |
184 | */ | |
185 | int sync_blockdev(struct block_device *bdev) | |
186 | { | |
5cee5815 | 187 | return __sync_blockdev(bdev, 1); |
585d3bc0 NP |
188 | } |
189 | EXPORT_SYMBOL(sync_blockdev); | |
190 | ||
191 | /* | |
192 | * Write out and wait upon all dirty data associated with this | |
193 | * device. Filesystem data as well as the underlying block | |
194 | * device. Takes the superblock lock. | |
195 | */ | |
196 | int fsync_bdev(struct block_device *bdev) | |
197 | { | |
198 | struct super_block *sb = get_super(bdev); | |
199 | if (sb) { | |
60b0680f | 200 | int res = sync_filesystem(sb); |
585d3bc0 NP |
201 | drop_super(sb); |
202 | return res; | |
203 | } | |
204 | return sync_blockdev(bdev); | |
205 | } | |
47e4491b | 206 | EXPORT_SYMBOL(fsync_bdev); |
585d3bc0 NP |
207 | |
208 | /** | |
209 | * freeze_bdev -- lock a filesystem and force it into a consistent state | |
210 | * @bdev: blockdevice to lock | |
211 | * | |
585d3bc0 NP |
212 | * If a superblock is found on this device, we take the s_umount semaphore |
213 | * on it to make sure nobody unmounts until the snapshot creation is done. | |
214 | * The reference counter (bd_fsfreeze_count) guarantees that only the last | |
215 | * unfreeze process can unfreeze the frozen filesystem actually when multiple | |
216 | * freeze requests arrive simultaneously. It counts up in freeze_bdev() and | |
217 | * count down in thaw_bdev(). When it becomes 0, thaw_bdev() will unfreeze | |
218 | * actually. | |
219 | */ | |
220 | struct super_block *freeze_bdev(struct block_device *bdev) | |
221 | { | |
222 | struct super_block *sb; | |
223 | int error = 0; | |
224 | ||
225 | mutex_lock(&bdev->bd_fsfreeze_mutex); | |
4504230a CH |
226 | if (++bdev->bd_fsfreeze_count > 1) { |
227 | /* | |
228 | * We don't even need to grab a reference - the first call | |
229 | * to freeze_bdev grab an active reference and only the last | |
230 | * thaw_bdev drops it. | |
231 | */ | |
585d3bc0 | 232 | sb = get_super(bdev); |
4504230a CH |
233 | drop_super(sb); |
234 | mutex_unlock(&bdev->bd_fsfreeze_mutex); | |
235 | return sb; | |
236 | } | |
237 | ||
238 | sb = get_active_super(bdev); | |
239 | if (!sb) | |
240 | goto out; | |
48b6bca6 BM |
241 | if (sb->s_op->freeze_super) |
242 | error = sb->s_op->freeze_super(sb); | |
243 | else | |
244 | error = freeze_super(sb); | |
18e9e510 JB |
245 | if (error) { |
246 | deactivate_super(sb); | |
247 | bdev->bd_fsfreeze_count--; | |
585d3bc0 | 248 | mutex_unlock(&bdev->bd_fsfreeze_mutex); |
18e9e510 | 249 | return ERR_PTR(error); |
585d3bc0 | 250 | } |
18e9e510 | 251 | deactivate_super(sb); |
4504230a | 252 | out: |
585d3bc0 NP |
253 | sync_blockdev(bdev); |
254 | mutex_unlock(&bdev->bd_fsfreeze_mutex); | |
4fadd7bb | 255 | return sb; /* thaw_bdev releases s->s_umount */ |
585d3bc0 NP |
256 | } |
257 | EXPORT_SYMBOL(freeze_bdev); | |
258 | ||
259 | /** | |
260 | * thaw_bdev -- unlock filesystem | |
261 | * @bdev: blockdevice to unlock | |
262 | * @sb: associated superblock | |
263 | * | |
264 | * Unlocks the filesystem and marks it writeable again after freeze_bdev(). | |
265 | */ | |
266 | int thaw_bdev(struct block_device *bdev, struct super_block *sb) | |
267 | { | |
4504230a | 268 | int error = -EINVAL; |
585d3bc0 NP |
269 | |
270 | mutex_lock(&bdev->bd_fsfreeze_mutex); | |
4504230a | 271 | if (!bdev->bd_fsfreeze_count) |
18e9e510 | 272 | goto out; |
4504230a CH |
273 | |
274 | error = 0; | |
275 | if (--bdev->bd_fsfreeze_count > 0) | |
18e9e510 | 276 | goto out; |
4504230a CH |
277 | |
278 | if (!sb) | |
18e9e510 | 279 | goto out; |
4504230a | 280 | |
48b6bca6 BM |
281 | if (sb->s_op->thaw_super) |
282 | error = sb->s_op->thaw_super(sb); | |
283 | else | |
284 | error = thaw_super(sb); | |
18e9e510 JB |
285 | if (error) { |
286 | bdev->bd_fsfreeze_count++; | |
287 | mutex_unlock(&bdev->bd_fsfreeze_mutex); | |
288 | return error; | |
289 | } | |
290 | out: | |
585d3bc0 NP |
291 | mutex_unlock(&bdev->bd_fsfreeze_mutex); |
292 | return 0; | |
293 | } | |
294 | EXPORT_SYMBOL(thaw_bdev); | |
295 | ||
1da177e4 LT |
296 | static int blkdev_writepage(struct page *page, struct writeback_control *wbc) |
297 | { | |
298 | return block_write_full_page(page, blkdev_get_block, wbc); | |
299 | } | |
300 | ||
301 | static int blkdev_readpage(struct file * file, struct page * page) | |
302 | { | |
303 | return block_read_full_page(page, blkdev_get_block); | |
304 | } | |
305 | ||
447f05bb AM |
306 | static int blkdev_readpages(struct file *file, struct address_space *mapping, |
307 | struct list_head *pages, unsigned nr_pages) | |
308 | { | |
309 | return mpage_readpages(mapping, pages, nr_pages, blkdev_get_block); | |
310 | } | |
311 | ||
6272b5a5 NP |
312 | static int blkdev_write_begin(struct file *file, struct address_space *mapping, |
313 | loff_t pos, unsigned len, unsigned flags, | |
314 | struct page **pagep, void **fsdata) | |
1da177e4 | 315 | { |
155130a4 CH |
316 | return block_write_begin(mapping, pos, len, flags, pagep, |
317 | blkdev_get_block); | |
1da177e4 LT |
318 | } |
319 | ||
6272b5a5 NP |
320 | static int blkdev_write_end(struct file *file, struct address_space *mapping, |
321 | loff_t pos, unsigned len, unsigned copied, | |
322 | struct page *page, void *fsdata) | |
1da177e4 | 323 | { |
6272b5a5 NP |
324 | int ret; |
325 | ret = block_write_end(file, mapping, pos, len, copied, page, fsdata); | |
326 | ||
327 | unlock_page(page); | |
328 | page_cache_release(page); | |
329 | ||
330 | return ret; | |
1da177e4 LT |
331 | } |
332 | ||
333 | /* | |
334 | * private llseek: | |
496ad9aa | 335 | * for a block special file file_inode(file)->i_size is zero |
1da177e4 LT |
336 | * so we compute the size by hand (just as in block_read/write above) |
337 | */ | |
965c8e59 | 338 | static loff_t block_llseek(struct file *file, loff_t offset, int whence) |
1da177e4 LT |
339 | { |
340 | struct inode *bd_inode = file->f_mapping->host; | |
1da177e4 LT |
341 | loff_t retval; |
342 | ||
1b1dcc1b | 343 | mutex_lock(&bd_inode->i_mutex); |
5d48f3a2 | 344 | retval = fixed_size_llseek(file, offset, whence, i_size_read(bd_inode)); |
1b1dcc1b | 345 | mutex_unlock(&bd_inode->i_mutex); |
1da177e4 LT |
346 | return retval; |
347 | } | |
348 | ||
02c24a82 | 349 | int blkdev_fsync(struct file *filp, loff_t start, loff_t end, int datasync) |
1da177e4 | 350 | { |
b8af67e2 AB |
351 | struct inode *bd_inode = filp->f_mapping->host; |
352 | struct block_device *bdev = I_BDEV(bd_inode); | |
ab0a9735 | 353 | int error; |
da5aa861 RW |
354 | |
355 | error = filemap_write_and_wait_range(filp->f_mapping, start, end); | |
356 | if (error) | |
357 | return error; | |
ab0a9735 | 358 | |
b8af67e2 AB |
359 | /* |
360 | * There is no need to serialise calls to blkdev_issue_flush with | |
361 | * i_mutex and doing so causes performance issues with concurrent | |
362 | * O_SYNC writers to a block device. | |
363 | */ | |
dd3932ed | 364 | error = blkdev_issue_flush(bdev, GFP_KERNEL, NULL); |
ab0a9735 CH |
365 | if (error == -EOPNOTSUPP) |
366 | error = 0; | |
b8af67e2 | 367 | |
ab0a9735 | 368 | return error; |
1da177e4 | 369 | } |
b1dd3b28 | 370 | EXPORT_SYMBOL(blkdev_fsync); |
1da177e4 | 371 | |
47a191fd MW |
372 | /** |
373 | * bdev_read_page() - Start reading a page from a block device | |
374 | * @bdev: The device to read the page from | |
375 | * @sector: The offset on the device to read the page to (need not be aligned) | |
376 | * @page: The page to read | |
377 | * | |
378 | * On entry, the page should be locked. It will be unlocked when the page | |
379 | * has been read. If the block driver implements rw_page synchronously, | |
380 | * that will be true on exit from this function, but it need not be. | |
381 | * | |
382 | * Errors returned by this function are usually "soft", eg out of memory, or | |
383 | * queue full; callers should try a different route to read this page rather | |
384 | * than propagate an error back up the stack. | |
385 | * | |
386 | * Return: negative errno if an error occurs, 0 if submission was successful. | |
387 | */ | |
388 | int bdev_read_page(struct block_device *bdev, sector_t sector, | |
389 | struct page *page) | |
390 | { | |
391 | const struct block_device_operations *ops = bdev->bd_disk->fops; | |
2e6edc95 DW |
392 | int result = -EOPNOTSUPP; |
393 | ||
f68eb1e7 | 394 | if (!ops->rw_page || bdev_get_integrity(bdev)) |
2e6edc95 DW |
395 | return result; |
396 | ||
3c92db6a | 397 | result = blk_queue_enter(bdev->bd_queue, false); |
2e6edc95 DW |
398 | if (result) |
399 | return result; | |
400 | result = ops->rw_page(bdev, sector + get_start_sect(bdev), page, READ); | |
401 | blk_queue_exit(bdev->bd_queue); | |
402 | return result; | |
47a191fd MW |
403 | } |
404 | EXPORT_SYMBOL_GPL(bdev_read_page); | |
405 | ||
406 | /** | |
407 | * bdev_write_page() - Start writing a page to a block device | |
408 | * @bdev: The device to write the page to | |
409 | * @sector: The offset on the device to write the page to (need not be aligned) | |
410 | * @page: The page to write | |
411 | * @wbc: The writeback_control for the write | |
412 | * | |
413 | * On entry, the page should be locked and not currently under writeback. | |
414 | * On exit, if the write started successfully, the page will be unlocked and | |
415 | * under writeback. If the write failed already (eg the driver failed to | |
416 | * queue the page to the device), the page will still be locked. If the | |
417 | * caller is a ->writepage implementation, it will need to unlock the page. | |
418 | * | |
419 | * Errors returned by this function are usually "soft", eg out of memory, or | |
420 | * queue full; callers should try a different route to write this page rather | |
421 | * than propagate an error back up the stack. | |
422 | * | |
423 | * Return: negative errno if an error occurs, 0 if submission was successful. | |
424 | */ | |
425 | int bdev_write_page(struct block_device *bdev, sector_t sector, | |
426 | struct page *page, struct writeback_control *wbc) | |
427 | { | |
428 | int result; | |
429 | int rw = (wbc->sync_mode == WB_SYNC_ALL) ? WRITE_SYNC : WRITE; | |
430 | const struct block_device_operations *ops = bdev->bd_disk->fops; | |
2e6edc95 | 431 | |
f68eb1e7 | 432 | if (!ops->rw_page || bdev_get_integrity(bdev)) |
47a191fd | 433 | return -EOPNOTSUPP; |
3c92db6a | 434 | result = blk_queue_enter(bdev->bd_queue, false); |
2e6edc95 DW |
435 | if (result) |
436 | return result; | |
437 | ||
47a191fd MW |
438 | set_page_writeback(page); |
439 | result = ops->rw_page(bdev, sector + get_start_sect(bdev), page, rw); | |
440 | if (result) | |
441 | end_page_writeback(page); | |
442 | else | |
443 | unlock_page(page); | |
2e6edc95 | 444 | blk_queue_exit(bdev->bd_queue); |
47a191fd MW |
445 | return result; |
446 | } | |
447 | EXPORT_SYMBOL_GPL(bdev_write_page); | |
448 | ||
dd22f551 MW |
449 | /** |
450 | * bdev_direct_access() - Get the address for directly-accessibly memory | |
451 | * @bdev: The device containing the memory | |
452 | * @sector: The offset within the device | |
453 | * @addr: Where to put the address of the memory | |
454 | * @pfn: The Page Frame Number for the memory | |
455 | * @size: The number of bytes requested | |
456 | * | |
457 | * If a block device is made up of directly addressable memory, this function | |
458 | * will tell the caller the PFN and the address of the memory. The address | |
459 | * may be directly dereferenced within the kernel without the need to call | |
460 | * ioremap(), kmap() or similar. The PFN is suitable for inserting into | |
461 | * page tables. | |
462 | * | |
463 | * Return: negative errno if an error occurs, otherwise the number of bytes | |
464 | * accessible at this address. | |
465 | */ | |
466 | long bdev_direct_access(struct block_device *bdev, sector_t sector, | |
e2e05394 | 467 | void __pmem **addr, unsigned long *pfn, long size) |
dd22f551 MW |
468 | { |
469 | long avail; | |
470 | const struct block_device_operations *ops = bdev->bd_disk->fops; | |
471 | ||
43c3dd08 MW |
472 | /* |
473 | * The device driver is allowed to sleep, in order to make the | |
474 | * memory directly accessible. | |
475 | */ | |
476 | might_sleep(); | |
477 | ||
dd22f551 MW |
478 | if (size < 0) |
479 | return size; | |
480 | if (!ops->direct_access) | |
481 | return -EOPNOTSUPP; | |
482 | if ((sector + DIV_ROUND_UP(size, 512)) > | |
483 | part_nr_sects_read(bdev->bd_part)) | |
484 | return -ERANGE; | |
485 | sector += get_start_sect(bdev); | |
486 | if (sector % (PAGE_SIZE / 512)) | |
487 | return -EINVAL; | |
cb389b9c | 488 | avail = ops->direct_access(bdev, sector, addr, pfn); |
dd22f551 MW |
489 | if (!avail) |
490 | return -ERANGE; | |
491 | return min(avail, size); | |
492 | } | |
493 | EXPORT_SYMBOL_GPL(bdev_direct_access); | |
494 | ||
1da177e4 LT |
495 | /* |
496 | * pseudo-fs | |
497 | */ | |
498 | ||
499 | static __cacheline_aligned_in_smp DEFINE_SPINLOCK(bdev_lock); | |
e18b890b | 500 | static struct kmem_cache * bdev_cachep __read_mostly; |
1da177e4 LT |
501 | |
502 | static struct inode *bdev_alloc_inode(struct super_block *sb) | |
503 | { | |
e94b1766 | 504 | struct bdev_inode *ei = kmem_cache_alloc(bdev_cachep, GFP_KERNEL); |
1da177e4 LT |
505 | if (!ei) |
506 | return NULL; | |
507 | return &ei->vfs_inode; | |
508 | } | |
509 | ||
fa0d7e3d | 510 | static void bdev_i_callback(struct rcu_head *head) |
1da177e4 | 511 | { |
fa0d7e3d | 512 | struct inode *inode = container_of(head, struct inode, i_rcu); |
1da177e4 LT |
513 | struct bdev_inode *bdi = BDEV_I(inode); |
514 | ||
1da177e4 LT |
515 | kmem_cache_free(bdev_cachep, bdi); |
516 | } | |
517 | ||
fa0d7e3d NP |
518 | static void bdev_destroy_inode(struct inode *inode) |
519 | { | |
520 | call_rcu(&inode->i_rcu, bdev_i_callback); | |
521 | } | |
522 | ||
51cc5068 | 523 | static void init_once(void *foo) |
1da177e4 LT |
524 | { |
525 | struct bdev_inode *ei = (struct bdev_inode *) foo; | |
526 | struct block_device *bdev = &ei->bdev; | |
527 | ||
a35afb83 CL |
528 | memset(bdev, 0, sizeof(*bdev)); |
529 | mutex_init(&bdev->bd_mutex); | |
a35afb83 CL |
530 | INIT_LIST_HEAD(&bdev->bd_inodes); |
531 | INIT_LIST_HEAD(&bdev->bd_list); | |
49731baa TH |
532 | #ifdef CONFIG_SYSFS |
533 | INIT_LIST_HEAD(&bdev->bd_holder_disks); | |
534 | #endif | |
d86db5cc | 535 | bdev->bd_bdi = &noop_backing_dev_info; |
a35afb83 | 536 | inode_init_once(&ei->vfs_inode); |
fcccf502 TS |
537 | /* Initialize mutex for freeze. */ |
538 | mutex_init(&bdev->bd_fsfreeze_mutex); | |
1da177e4 LT |
539 | } |
540 | ||
541 | static inline void __bd_forget(struct inode *inode) | |
542 | { | |
543 | list_del_init(&inode->i_devices); | |
544 | inode->i_bdev = NULL; | |
545 | inode->i_mapping = &inode->i_data; | |
546 | } | |
547 | ||
b57922d9 | 548 | static void bdev_evict_inode(struct inode *inode) |
1da177e4 LT |
549 | { |
550 | struct block_device *bdev = &BDEV_I(inode)->bdev; | |
551 | struct list_head *p; | |
91b0abe3 | 552 | truncate_inode_pages_final(&inode->i_data); |
b57922d9 | 553 | invalidate_inode_buffers(inode); /* is it needed here? */ |
dbd5768f | 554 | clear_inode(inode); |
1da177e4 LT |
555 | spin_lock(&bdev_lock); |
556 | while ( (p = bdev->bd_inodes.next) != &bdev->bd_inodes ) { | |
557 | __bd_forget(list_entry(p, struct inode, i_devices)); | |
558 | } | |
559 | list_del_init(&bdev->bd_list); | |
560 | spin_unlock(&bdev_lock); | |
3b9d0678 JK |
561 | /* Detach inode from wb early as bdi_put() may free bdi->wb */ |
562 | inode_detach_wb(inode); | |
d86db5cc | 563 | if (bdev->bd_bdi != &noop_backing_dev_info) { |
e28ae314 | 564 | bdi_put(bdev->bd_bdi); |
d86db5cc JK |
565 | bdev->bd_bdi = &noop_backing_dev_info; |
566 | } | |
1da177e4 LT |
567 | } |
568 | ||
ee9b6d61 | 569 | static const struct super_operations bdev_sops = { |
1da177e4 LT |
570 | .statfs = simple_statfs, |
571 | .alloc_inode = bdev_alloc_inode, | |
572 | .destroy_inode = bdev_destroy_inode, | |
573 | .drop_inode = generic_delete_inode, | |
b57922d9 | 574 | .evict_inode = bdev_evict_inode, |
1da177e4 LT |
575 | }; |
576 | ||
51139ada AV |
577 | static struct dentry *bd_mount(struct file_system_type *fs_type, |
578 | int flags, const char *dev_name, void *data) | |
1da177e4 | 579 | { |
b502bd11 | 580 | return mount_pseudo(fs_type, "bdev:", &bdev_sops, NULL, BDEVFS_MAGIC); |
1da177e4 LT |
581 | } |
582 | ||
583 | static struct file_system_type bd_type = { | |
584 | .name = "bdev", | |
51139ada | 585 | .mount = bd_mount, |
1da177e4 LT |
586 | .kill_sb = kill_anon_super, |
587 | }; | |
588 | ||
a212b105 TH |
589 | struct super_block *blockdev_superblock __read_mostly; |
590 | EXPORT_SYMBOL_GPL(blockdev_superblock); | |
1da177e4 LT |
591 | |
592 | void __init bdev_cache_init(void) | |
593 | { | |
594 | int err; | |
ace8577a | 595 | static struct vfsmount *bd_mnt; |
c2acf7b9 | 596 | |
1da177e4 | 597 | bdev_cachep = kmem_cache_create("bdev_cache", sizeof(struct bdev_inode), |
fffb60f9 PJ |
598 | 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT| |
599 | SLAB_MEM_SPREAD|SLAB_PANIC), | |
20c2df83 | 600 | init_once); |
1da177e4 LT |
601 | err = register_filesystem(&bd_type); |
602 | if (err) | |
603 | panic("Cannot register bdev pseudo-fs"); | |
604 | bd_mnt = kern_mount(&bd_type); | |
1da177e4 LT |
605 | if (IS_ERR(bd_mnt)) |
606 | panic("Cannot create bdev pseudo-fs"); | |
ace8577a | 607 | blockdev_superblock = bd_mnt->mnt_sb; /* For writeback */ |
1da177e4 LT |
608 | } |
609 | ||
610 | /* | |
611 | * Most likely _very_ bad one - but then it's hardly critical for small | |
612 | * /dev and can be fixed when somebody will need really large one. | |
613 | * Keep in mind that it will be fed through icache hash function too. | |
614 | */ | |
615 | static inline unsigned long hash(dev_t dev) | |
616 | { | |
617 | return MAJOR(dev)+MINOR(dev); | |
618 | } | |
619 | ||
620 | static int bdev_test(struct inode *inode, void *data) | |
621 | { | |
622 | return BDEV_I(inode)->bdev.bd_dev == *(dev_t *)data; | |
623 | } | |
624 | ||
625 | static int bdev_set(struct inode *inode, void *data) | |
626 | { | |
627 | BDEV_I(inode)->bdev.bd_dev = *(dev_t *)data; | |
628 | return 0; | |
629 | } | |
630 | ||
631 | static LIST_HEAD(all_bdevs); | |
632 | ||
7d75b953 JK |
633 | /* |
634 | * If there is a bdev inode for this device, unhash it so that it gets evicted | |
635 | * as soon as last inode reference is dropped. | |
636 | */ | |
637 | void bdev_unhash_inode(dev_t dev) | |
638 | { | |
639 | struct inode *inode; | |
640 | ||
641 | inode = ilookup5(blockdev_superblock, hash(dev), bdev_test, &dev); | |
642 | if (inode) { | |
643 | remove_inode_hash(inode); | |
644 | iput(inode); | |
645 | } | |
646 | } | |
647 | ||
1da177e4 LT |
648 | struct block_device *bdget(dev_t dev) |
649 | { | |
650 | struct block_device *bdev; | |
651 | struct inode *inode; | |
652 | ||
c2acf7b9 | 653 | inode = iget5_locked(blockdev_superblock, hash(dev), |
1da177e4 LT |
654 | bdev_test, bdev_set, &dev); |
655 | ||
656 | if (!inode) | |
657 | return NULL; | |
658 | ||
659 | bdev = &BDEV_I(inode)->bdev; | |
660 | ||
661 | if (inode->i_state & I_NEW) { | |
662 | bdev->bd_contains = NULL; | |
782b94cd | 663 | bdev->bd_super = NULL; |
1da177e4 LT |
664 | bdev->bd_inode = inode; |
665 | bdev->bd_block_size = (1 << inode->i_blkbits); | |
666 | bdev->bd_part_count = 0; | |
667 | bdev->bd_invalidated = 0; | |
668 | inode->i_mode = S_IFBLK; | |
669 | inode->i_rdev = dev; | |
670 | inode->i_bdev = bdev; | |
671 | inode->i_data.a_ops = &def_blk_aops; | |
672 | mapping_set_gfp_mask(&inode->i_data, GFP_USER); | |
1da177e4 LT |
673 | spin_lock(&bdev_lock); |
674 | list_add(&bdev->bd_list, &all_bdevs); | |
675 | spin_unlock(&bdev_lock); | |
676 | unlock_new_inode(inode); | |
677 | } | |
678 | return bdev; | |
679 | } | |
680 | ||
681 | EXPORT_SYMBOL(bdget); | |
682 | ||
dddac6a7 AJ |
683 | /** |
684 | * bdgrab -- Grab a reference to an already referenced block device | |
685 | * @bdev: Block device to grab a reference to. | |
686 | */ | |
687 | struct block_device *bdgrab(struct block_device *bdev) | |
688 | { | |
7de9c6ee | 689 | ihold(bdev->bd_inode); |
dddac6a7 AJ |
690 | return bdev; |
691 | } | |
c1681bf8 | 692 | EXPORT_SYMBOL(bdgrab); |
dddac6a7 | 693 | |
1da177e4 LT |
694 | long nr_blockdev_pages(void) |
695 | { | |
203a2935 | 696 | struct block_device *bdev; |
1da177e4 LT |
697 | long ret = 0; |
698 | spin_lock(&bdev_lock); | |
203a2935 | 699 | list_for_each_entry(bdev, &all_bdevs, bd_list) { |
1da177e4 LT |
700 | ret += bdev->bd_inode->i_mapping->nrpages; |
701 | } | |
702 | spin_unlock(&bdev_lock); | |
703 | return ret; | |
704 | } | |
705 | ||
706 | void bdput(struct block_device *bdev) | |
707 | { | |
708 | iput(bdev->bd_inode); | |
709 | } | |
710 | ||
711 | EXPORT_SYMBOL(bdput); | |
712 | ||
713 | static struct block_device *bd_acquire(struct inode *inode) | |
714 | { | |
715 | struct block_device *bdev; | |
09d967c6 | 716 | |
1da177e4 LT |
717 | spin_lock(&bdev_lock); |
718 | bdev = inode->i_bdev; | |
387af5e4 | 719 | if (bdev && !inode_unhashed(bdev->bd_inode)) { |
7de9c6ee | 720 | ihold(bdev->bd_inode); |
1da177e4 LT |
721 | spin_unlock(&bdev_lock); |
722 | return bdev; | |
723 | } | |
724 | spin_unlock(&bdev_lock); | |
09d967c6 | 725 | |
387af5e4 JK |
726 | /* |
727 | * i_bdev references block device inode that was already shut down | |
728 | * (corresponding device got removed). Remove the reference and look | |
729 | * up block device inode again just in case new device got | |
730 | * reestablished under the same device number. | |
731 | */ | |
732 | if (bdev) | |
733 | bd_forget(inode); | |
734 | ||
1da177e4 LT |
735 | bdev = bdget(inode->i_rdev); |
736 | if (bdev) { | |
737 | spin_lock(&bdev_lock); | |
09d967c6 OH |
738 | if (!inode->i_bdev) { |
739 | /* | |
7de9c6ee | 740 | * We take an additional reference to bd_inode, |
09d967c6 OH |
741 | * and it's released in clear_inode() of inode. |
742 | * So, we can access it via ->i_mapping always | |
743 | * without igrab(). | |
744 | */ | |
7de9c6ee | 745 | ihold(bdev->bd_inode); |
09d967c6 OH |
746 | inode->i_bdev = bdev; |
747 | inode->i_mapping = bdev->bd_inode->i_mapping; | |
748 | list_add(&inode->i_devices, &bdev->bd_inodes); | |
749 | } | |
1da177e4 LT |
750 | spin_unlock(&bdev_lock); |
751 | } | |
752 | return bdev; | |
753 | } | |
754 | ||
755 | /* Call when you free inode */ | |
756 | ||
757 | void bd_forget(struct inode *inode) | |
758 | { | |
09d967c6 OH |
759 | struct block_device *bdev = NULL; |
760 | ||
1da177e4 | 761 | spin_lock(&bdev_lock); |
b4ea2eaa YH |
762 | if (!sb_is_blkdev_sb(inode->i_sb)) |
763 | bdev = inode->i_bdev; | |
764 | __bd_forget(inode); | |
1da177e4 | 765 | spin_unlock(&bdev_lock); |
09d967c6 OH |
766 | |
767 | if (bdev) | |
768 | iput(bdev->bd_inode); | |
1da177e4 LT |
769 | } |
770 | ||
1a3cbbc5 TH |
771 | /** |
772 | * bd_may_claim - test whether a block device can be claimed | |
773 | * @bdev: block device of interest | |
774 | * @whole: whole block device containing @bdev, may equal @bdev | |
775 | * @holder: holder trying to claim @bdev | |
776 | * | |
25985edc | 777 | * Test whether @bdev can be claimed by @holder. |
1a3cbbc5 TH |
778 | * |
779 | * CONTEXT: | |
780 | * spin_lock(&bdev_lock). | |
781 | * | |
782 | * RETURNS: | |
783 | * %true if @bdev can be claimed, %false otherwise. | |
784 | */ | |
785 | static bool bd_may_claim(struct block_device *bdev, struct block_device *whole, | |
786 | void *holder) | |
1da177e4 | 787 | { |
1da177e4 | 788 | if (bdev->bd_holder == holder) |
1a3cbbc5 | 789 | return true; /* already a holder */ |
1da177e4 | 790 | else if (bdev->bd_holder != NULL) |
1a3cbbc5 | 791 | return false; /* held by someone else */ |
2396dc5d | 792 | else if (whole == bdev) |
1a3cbbc5 | 793 | return true; /* is a whole device which isn't held */ |
1da177e4 | 794 | |
e525fd89 | 795 | else if (whole->bd_holder == bd_may_claim) |
1a3cbbc5 TH |
796 | return true; /* is a partition of a device that is being partitioned */ |
797 | else if (whole->bd_holder != NULL) | |
798 | return false; /* is a partition of a held device */ | |
1da177e4 | 799 | else |
1a3cbbc5 TH |
800 | return true; /* is a partition of an un-held device */ |
801 | } | |
802 | ||
6b4517a7 TH |
803 | /** |
804 | * bd_prepare_to_claim - prepare to claim a block device | |
805 | * @bdev: block device of interest | |
806 | * @whole: the whole device containing @bdev, may equal @bdev | |
807 | * @holder: holder trying to claim @bdev | |
808 | * | |
809 | * Prepare to claim @bdev. This function fails if @bdev is already | |
810 | * claimed by another holder and waits if another claiming is in | |
811 | * progress. This function doesn't actually claim. On successful | |
812 | * return, the caller has ownership of bd_claiming and bd_holder[s]. | |
813 | * | |
814 | * CONTEXT: | |
815 | * spin_lock(&bdev_lock). Might release bdev_lock, sleep and regrab | |
816 | * it multiple times. | |
817 | * | |
818 | * RETURNS: | |
819 | * 0 if @bdev can be claimed, -EBUSY otherwise. | |
820 | */ | |
821 | static int bd_prepare_to_claim(struct block_device *bdev, | |
822 | struct block_device *whole, void *holder) | |
823 | { | |
824 | retry: | |
825 | /* if someone else claimed, fail */ | |
826 | if (!bd_may_claim(bdev, whole, holder)) | |
827 | return -EBUSY; | |
828 | ||
e75aa858 TH |
829 | /* if claiming is already in progress, wait for it to finish */ |
830 | if (whole->bd_claiming) { | |
6b4517a7 TH |
831 | wait_queue_head_t *wq = bit_waitqueue(&whole->bd_claiming, 0); |
832 | DEFINE_WAIT(wait); | |
833 | ||
834 | prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE); | |
835 | spin_unlock(&bdev_lock); | |
836 | schedule(); | |
837 | finish_wait(wq, &wait); | |
838 | spin_lock(&bdev_lock); | |
839 | goto retry; | |
840 | } | |
841 | ||
842 | /* yay, all mine */ | |
843 | return 0; | |
844 | } | |
845 | ||
846 | /** | |
847 | * bd_start_claiming - start claiming a block device | |
848 | * @bdev: block device of interest | |
849 | * @holder: holder trying to claim @bdev | |
850 | * | |
851 | * @bdev is about to be opened exclusively. Check @bdev can be opened | |
852 | * exclusively and mark that an exclusive open is in progress. Each | |
853 | * successful call to this function must be matched with a call to | |
b0018361 NP |
854 | * either bd_finish_claiming() or bd_abort_claiming() (which do not |
855 | * fail). | |
856 | * | |
857 | * This function is used to gain exclusive access to the block device | |
858 | * without actually causing other exclusive open attempts to fail. It | |
859 | * should be used when the open sequence itself requires exclusive | |
860 | * access but may subsequently fail. | |
6b4517a7 TH |
861 | * |
862 | * CONTEXT: | |
863 | * Might sleep. | |
864 | * | |
865 | * RETURNS: | |
866 | * Pointer to the block device containing @bdev on success, ERR_PTR() | |
867 | * value on failure. | |
868 | */ | |
869 | static struct block_device *bd_start_claiming(struct block_device *bdev, | |
870 | void *holder) | |
871 | { | |
872 | struct gendisk *disk; | |
873 | struct block_device *whole; | |
874 | int partno, err; | |
875 | ||
876 | might_sleep(); | |
877 | ||
878 | /* | |
879 | * @bdev might not have been initialized properly yet, look up | |
880 | * and grab the outer block device the hard way. | |
881 | */ | |
882 | disk = get_gendisk(bdev->bd_dev, &partno); | |
883 | if (!disk) | |
884 | return ERR_PTR(-ENXIO); | |
885 | ||
d4c208b8 TH |
886 | /* |
887 | * Normally, @bdev should equal what's returned from bdget_disk() | |
888 | * if partno is 0; however, some drivers (floppy) use multiple | |
889 | * bdev's for the same physical device and @bdev may be one of the | |
890 | * aliases. Keep @bdev if partno is 0. This means claimer | |
891 | * tracking is broken for those devices but it has always been that | |
892 | * way. | |
893 | */ | |
894 | if (partno) | |
895 | whole = bdget_disk(disk, 0); | |
896 | else | |
897 | whole = bdgrab(bdev); | |
898 | ||
cf342570 | 899 | module_put(disk->fops->owner); |
6b4517a7 TH |
900 | put_disk(disk); |
901 | if (!whole) | |
902 | return ERR_PTR(-ENOMEM); | |
903 | ||
904 | /* prepare to claim, if successful, mark claiming in progress */ | |
905 | spin_lock(&bdev_lock); | |
906 | ||
907 | err = bd_prepare_to_claim(bdev, whole, holder); | |
908 | if (err == 0) { | |
909 | whole->bd_claiming = holder; | |
910 | spin_unlock(&bdev_lock); | |
911 | return whole; | |
912 | } else { | |
913 | spin_unlock(&bdev_lock); | |
914 | bdput(whole); | |
915 | return ERR_PTR(err); | |
916 | } | |
917 | } | |
918 | ||
641dc636 | 919 | #ifdef CONFIG_SYSFS |
49731baa TH |
920 | struct bd_holder_disk { |
921 | struct list_head list; | |
922 | struct gendisk *disk; | |
923 | int refcnt; | |
924 | }; | |
925 | ||
926 | static struct bd_holder_disk *bd_find_holder_disk(struct block_device *bdev, | |
927 | struct gendisk *disk) | |
928 | { | |
929 | struct bd_holder_disk *holder; | |
930 | ||
931 | list_for_each_entry(holder, &bdev->bd_holder_disks, list) | |
932 | if (holder->disk == disk) | |
933 | return holder; | |
934 | return NULL; | |
935 | } | |
936 | ||
4d7dd8fd | 937 | static int add_symlink(struct kobject *from, struct kobject *to) |
641dc636 | 938 | { |
4d7dd8fd | 939 | return sysfs_create_link(from, to, kobject_name(to)); |
641dc636 JN |
940 | } |
941 | ||
942 | static void del_symlink(struct kobject *from, struct kobject *to) | |
943 | { | |
641dc636 JN |
944 | sysfs_remove_link(from, kobject_name(to)); |
945 | } | |
946 | ||
df6c0cd9 | 947 | /** |
e09b457b TH |
948 | * bd_link_disk_holder - create symlinks between holding disk and slave bdev |
949 | * @bdev: the claimed slave bdev | |
950 | * @disk: the holding disk | |
df6c0cd9 | 951 | * |
49731baa TH |
952 | * DON'T USE THIS UNLESS YOU'RE ALREADY USING IT. |
953 | * | |
e09b457b | 954 | * This functions creates the following sysfs symlinks. |
641dc636 | 955 | * |
e09b457b TH |
956 | * - from "slaves" directory of the holder @disk to the claimed @bdev |
957 | * - from "holders" directory of the @bdev to the holder @disk | |
641dc636 | 958 | * |
e09b457b TH |
959 | * For example, if /dev/dm-0 maps to /dev/sda and disk for dm-0 is |
960 | * passed to bd_link_disk_holder(), then: | |
641dc636 | 961 | * |
e09b457b TH |
962 | * /sys/block/dm-0/slaves/sda --> /sys/block/sda |
963 | * /sys/block/sda/holders/dm-0 --> /sys/block/dm-0 | |
641dc636 | 964 | * |
e09b457b TH |
965 | * The caller must have claimed @bdev before calling this function and |
966 | * ensure that both @bdev and @disk are valid during the creation and | |
967 | * lifetime of these symlinks. | |
641dc636 | 968 | * |
e09b457b TH |
969 | * CONTEXT: |
970 | * Might sleep. | |
641dc636 | 971 | * |
e09b457b TH |
972 | * RETURNS: |
973 | * 0 on success, -errno on failure. | |
641dc636 | 974 | */ |
e09b457b | 975 | int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk) |
641dc636 | 976 | { |
49731baa | 977 | struct bd_holder_disk *holder; |
e09b457b | 978 | int ret = 0; |
641dc636 | 979 | |
2e7b651d | 980 | mutex_lock(&bdev->bd_mutex); |
df6c0cd9 | 981 | |
49731baa | 982 | WARN_ON_ONCE(!bdev->bd_holder); |
4e91672c | 983 | |
e09b457b TH |
984 | /* FIXME: remove the following once add_disk() handles errors */ |
985 | if (WARN_ON(!disk->slave_dir || !bdev->bd_part->holder_dir)) | |
986 | goto out_unlock; | |
4e91672c | 987 | |
49731baa TH |
988 | holder = bd_find_holder_disk(bdev, disk); |
989 | if (holder) { | |
990 | holder->refcnt++; | |
e09b457b | 991 | goto out_unlock; |
49731baa | 992 | } |
641dc636 | 993 | |
49731baa TH |
994 | holder = kzalloc(sizeof(*holder), GFP_KERNEL); |
995 | if (!holder) { | |
996 | ret = -ENOMEM; | |
e09b457b TH |
997 | goto out_unlock; |
998 | } | |
641dc636 | 999 | |
49731baa TH |
1000 | INIT_LIST_HEAD(&holder->list); |
1001 | holder->disk = disk; | |
1002 | holder->refcnt = 1; | |
1003 | ||
1004 | ret = add_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj); | |
1005 | if (ret) | |
1006 | goto out_free; | |
1007 | ||
1008 | ret = add_symlink(bdev->bd_part->holder_dir, &disk_to_dev(disk)->kobj); | |
1009 | if (ret) | |
1010 | goto out_del; | |
e7407d16 TH |
1011 | /* |
1012 | * bdev could be deleted beneath us which would implicitly destroy | |
1013 | * the holder directory. Hold on to it. | |
1014 | */ | |
1015 | kobject_get(bdev->bd_part->holder_dir); | |
49731baa TH |
1016 | |
1017 | list_add(&holder->list, &bdev->bd_holder_disks); | |
1018 | goto out_unlock; | |
1019 | ||
1020 | out_del: | |
1021 | del_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj); | |
1022 | out_free: | |
1023 | kfree(holder); | |
e09b457b | 1024 | out_unlock: |
b4cf1b72 | 1025 | mutex_unlock(&bdev->bd_mutex); |
e09b457b | 1026 | return ret; |
641dc636 | 1027 | } |
e09b457b | 1028 | EXPORT_SYMBOL_GPL(bd_link_disk_holder); |
641dc636 | 1029 | |
49731baa TH |
1030 | /** |
1031 | * bd_unlink_disk_holder - destroy symlinks created by bd_link_disk_holder() | |
1032 | * @bdev: the calimed slave bdev | |
1033 | * @disk: the holding disk | |
1034 | * | |
1035 | * DON'T USE THIS UNLESS YOU'RE ALREADY USING IT. | |
1036 | * | |
1037 | * CONTEXT: | |
1038 | * Might sleep. | |
1039 | */ | |
1040 | void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk) | |
641dc636 | 1041 | { |
49731baa | 1042 | struct bd_holder_disk *holder; |
641dc636 | 1043 | |
49731baa | 1044 | mutex_lock(&bdev->bd_mutex); |
641dc636 | 1045 | |
49731baa TH |
1046 | holder = bd_find_holder_disk(bdev, disk); |
1047 | ||
1048 | if (!WARN_ON_ONCE(holder == NULL) && !--holder->refcnt) { | |
1049 | del_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj); | |
1050 | del_symlink(bdev->bd_part->holder_dir, | |
1051 | &disk_to_dev(disk)->kobj); | |
e7407d16 | 1052 | kobject_put(bdev->bd_part->holder_dir); |
49731baa TH |
1053 | list_del_init(&holder->list); |
1054 | kfree(holder); | |
1055 | } | |
1056 | ||
1057 | mutex_unlock(&bdev->bd_mutex); | |
1da177e4 | 1058 | } |
49731baa | 1059 | EXPORT_SYMBOL_GPL(bd_unlink_disk_holder); |
641dc636 | 1060 | #endif |
1da177e4 | 1061 | |
56ade44b AP |
1062 | /** |
1063 | * flush_disk - invalidates all buffer-cache entries on a disk | |
1064 | * | |
1065 | * @bdev: struct block device to be flushed | |
e6eb5ce1 | 1066 | * @kill_dirty: flag to guide handling of dirty inodes |
56ade44b AP |
1067 | * |
1068 | * Invalidates all buffer-cache entries on a disk. It should be called | |
1069 | * when a disk has been changed -- either by a media change or online | |
1070 | * resize. | |
1071 | */ | |
93b270f7 | 1072 | static void flush_disk(struct block_device *bdev, bool kill_dirty) |
56ade44b | 1073 | { |
93b270f7 | 1074 | if (__invalidate_device(bdev, kill_dirty)) { |
56ade44b AP |
1075 | char name[BDEVNAME_SIZE] = ""; |
1076 | ||
1077 | if (bdev->bd_disk) | |
1078 | disk_name(bdev->bd_disk, 0, name); | |
1079 | printk(KERN_WARNING "VFS: busy inodes on changed media or " | |
1080 | "resized disk %s\n", name); | |
1081 | } | |
1082 | ||
1083 | if (!bdev->bd_disk) | |
1084 | return; | |
d27769ec | 1085 | if (disk_part_scan_enabled(bdev->bd_disk)) |
56ade44b AP |
1086 | bdev->bd_invalidated = 1; |
1087 | } | |
1088 | ||
c3279d14 | 1089 | /** |
57d1b536 | 1090 | * check_disk_size_change - checks for disk size change and adjusts bdev size. |
c3279d14 AP |
1091 | * @disk: struct gendisk to check |
1092 | * @bdev: struct bdev to adjust. | |
1093 | * | |
1094 | * This routine checks to see if the bdev size does not match the disk size | |
1095 | * and adjusts it if it differs. | |
1096 | */ | |
1097 | void check_disk_size_change(struct gendisk *disk, struct block_device *bdev) | |
1098 | { | |
1099 | loff_t disk_size, bdev_size; | |
1100 | ||
1101 | disk_size = (loff_t)get_capacity(disk) << 9; | |
1102 | bdev_size = i_size_read(bdev->bd_inode); | |
1103 | if (disk_size != bdev_size) { | |
1104 | char name[BDEVNAME_SIZE]; | |
1105 | ||
1106 | disk_name(disk, 0, name); | |
1107 | printk(KERN_INFO | |
1108 | "%s: detected capacity change from %lld to %lld\n", | |
1109 | name, bdev_size, disk_size); | |
1110 | i_size_write(bdev->bd_inode, disk_size); | |
93b270f7 | 1111 | flush_disk(bdev, false); |
c3279d14 AP |
1112 | } |
1113 | } | |
1114 | EXPORT_SYMBOL(check_disk_size_change); | |
1115 | ||
0c002c2f | 1116 | /** |
57d1b536 | 1117 | * revalidate_disk - wrapper for lower-level driver's revalidate_disk call-back |
0c002c2f AP |
1118 | * @disk: struct gendisk to be revalidated |
1119 | * | |
1120 | * This routine is a wrapper for lower-level driver's revalidate_disk | |
1121 | * call-backs. It is used to do common pre and post operations needed | |
1122 | * for all revalidate_disk operations. | |
1123 | */ | |
1124 | int revalidate_disk(struct gendisk *disk) | |
1125 | { | |
c3279d14 | 1126 | struct block_device *bdev; |
0c002c2f AP |
1127 | int ret = 0; |
1128 | ||
1129 | if (disk->fops->revalidate_disk) | |
1130 | ret = disk->fops->revalidate_disk(disk); | |
c3279d14 AP |
1131 | bdev = bdget_disk(disk, 0); |
1132 | if (!bdev) | |
1133 | return ret; | |
1134 | ||
1135 | mutex_lock(&bdev->bd_mutex); | |
1136 | check_disk_size_change(disk, bdev); | |
7630b661 | 1137 | bdev->bd_invalidated = 0; |
c3279d14 AP |
1138 | mutex_unlock(&bdev->bd_mutex); |
1139 | bdput(bdev); | |
0c002c2f AP |
1140 | return ret; |
1141 | } | |
1142 | EXPORT_SYMBOL(revalidate_disk); | |
1143 | ||
1da177e4 LT |
1144 | /* |
1145 | * This routine checks whether a removable media has been changed, | |
1146 | * and invalidates all buffer-cache-entries in that case. This | |
1147 | * is a relatively slow routine, so we have to try to minimize using | |
1148 | * it. Thus it is called only upon a 'mount' or 'open'. This | |
1149 | * is the best way of combining speed and utility, I think. | |
1150 | * People changing diskettes in the middle of an operation deserve | |
1151 | * to lose :-) | |
1152 | */ | |
1153 | int check_disk_change(struct block_device *bdev) | |
1154 | { | |
1155 | struct gendisk *disk = bdev->bd_disk; | |
83d5cde4 | 1156 | const struct block_device_operations *bdops = disk->fops; |
77ea887e | 1157 | unsigned int events; |
1da177e4 | 1158 | |
77ea887e TH |
1159 | events = disk_clear_events(disk, DISK_EVENT_MEDIA_CHANGE | |
1160 | DISK_EVENT_EJECT_REQUEST); | |
1161 | if (!(events & DISK_EVENT_MEDIA_CHANGE)) | |
1da177e4 LT |
1162 | return 0; |
1163 | ||
93b270f7 | 1164 | flush_disk(bdev, true); |
1da177e4 LT |
1165 | if (bdops->revalidate_disk) |
1166 | bdops->revalidate_disk(bdev->bd_disk); | |
1da177e4 LT |
1167 | return 1; |
1168 | } | |
1169 | ||
1170 | EXPORT_SYMBOL(check_disk_change); | |
1171 | ||
1172 | void bd_set_size(struct block_device *bdev, loff_t size) | |
1173 | { | |
e1defc4f | 1174 | unsigned bsize = bdev_logical_block_size(bdev); |
1da177e4 | 1175 | |
d646a02a GC |
1176 | mutex_lock(&bdev->bd_inode->i_mutex); |
1177 | i_size_write(bdev->bd_inode, size); | |
1178 | mutex_unlock(&bdev->bd_inode->i_mutex); | |
1da177e4 LT |
1179 | while (bsize < PAGE_CACHE_SIZE) { |
1180 | if (size & bsize) | |
1181 | break; | |
1182 | bsize <<= 1; | |
1183 | } | |
1184 | bdev->bd_block_size = bsize; | |
1185 | bdev->bd_inode->i_blkbits = blksize_bits(bsize); | |
1186 | } | |
1187 | EXPORT_SYMBOL(bd_set_size); | |
1188 | ||
4385bab1 | 1189 | static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part); |
37be4124 | 1190 | |
6d740cd5 PZ |
1191 | /* |
1192 | * bd_mutex locking: | |
1193 | * | |
1194 | * mutex_lock(part->bd_mutex) | |
1195 | * mutex_lock_nested(whole->bd_mutex, 1) | |
1196 | */ | |
1197 | ||
572c4892 | 1198 | static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part) |
1da177e4 | 1199 | { |
1da177e4 | 1200 | struct gendisk *disk; |
523e1d39 | 1201 | struct module *owner; |
7db9cfd3 | 1202 | int ret; |
cf771cb5 | 1203 | int partno; |
fe6e9c1f AV |
1204 | int perm = 0; |
1205 | ||
572c4892 | 1206 | if (mode & FMODE_READ) |
fe6e9c1f | 1207 | perm |= MAY_READ; |
572c4892 | 1208 | if (mode & FMODE_WRITE) |
fe6e9c1f AV |
1209 | perm |= MAY_WRITE; |
1210 | /* | |
1211 | * hooks: /n/, see "layering violations". | |
1212 | */ | |
b7300b78 CW |
1213 | if (!for_part) { |
1214 | ret = devcgroup_inode_permission(bdev->bd_inode, perm); | |
1215 | if (ret != 0) { | |
1216 | bdput(bdev); | |
1217 | return ret; | |
1218 | } | |
82666020 | 1219 | } |
7db9cfd3 | 1220 | |
d3374825 | 1221 | restart: |
0762b8bd | 1222 | |
89f97496 | 1223 | ret = -ENXIO; |
cf771cb5 | 1224 | disk = get_gendisk(bdev->bd_dev, &partno); |
0762b8bd | 1225 | if (!disk) |
6e9624b8 | 1226 | goto out; |
523e1d39 | 1227 | owner = disk->fops->owner; |
1da177e4 | 1228 | |
69e02c59 | 1229 | disk_block_events(disk); |
6796bf54 | 1230 | mutex_lock_nested(&bdev->bd_mutex, for_part); |
1da177e4 LT |
1231 | if (!bdev->bd_openers) { |
1232 | bdev->bd_disk = disk; | |
87192a2a | 1233 | bdev->bd_queue = disk->queue; |
1da177e4 | 1234 | bdev->bd_contains = bdev; |
bbab37dd | 1235 | bdev->bd_inode->i_flags = disk->fops->direct_access ? S_DAX : 0; |
e28ae314 | 1236 | |
cf771cb5 | 1237 | if (!partno) { |
89f97496 TH |
1238 | ret = -ENXIO; |
1239 | bdev->bd_part = disk_get_part(disk, partno); | |
1240 | if (!bdev->bd_part) | |
1241 | goto out_clear; | |
1242 | ||
1196f8b8 | 1243 | ret = 0; |
1da177e4 | 1244 | if (disk->fops->open) { |
572c4892 | 1245 | ret = disk->fops->open(bdev, mode); |
d3374825 N |
1246 | if (ret == -ERESTARTSYS) { |
1247 | /* Lost a race with 'disk' being | |
1248 | * deleted, try again. | |
1249 | * See md.c | |
1250 | */ | |
1251 | disk_put_part(bdev->bd_part); | |
1252 | bdev->bd_part = NULL; | |
d3374825 | 1253 | bdev->bd_disk = NULL; |
87192a2a | 1254 | bdev->bd_queue = NULL; |
d3374825 | 1255 | mutex_unlock(&bdev->bd_mutex); |
69e02c59 | 1256 | disk_unblock_events(disk); |
69e02c59 | 1257 | put_disk(disk); |
523e1d39 | 1258 | module_put(owner); |
d3374825 N |
1259 | goto restart; |
1260 | } | |
1da177e4 | 1261 | } |
7e69723f | 1262 | |
b83ae6d4 | 1263 | if (!ret) |
7e69723f | 1264 | bd_set_size(bdev,(loff_t)get_capacity(disk)<<9); |
7e69723f | 1265 | |
1196f8b8 TH |
1266 | /* |
1267 | * If the device is invalidated, rescan partition | |
1268 | * if open succeeded or failed with -ENOMEDIUM. | |
1269 | * The latter is necessary to prevent ghost | |
1270 | * partitions on a removed medium. | |
1271 | */ | |
fe316bf2 JN |
1272 | if (bdev->bd_invalidated) { |
1273 | if (!ret) | |
1274 | rescan_partitions(disk, bdev); | |
1275 | else if (ret == -ENOMEDIUM) | |
1276 | invalidate_partitions(disk, bdev); | |
1277 | } | |
1196f8b8 TH |
1278 | if (ret) |
1279 | goto out_clear; | |
1da177e4 | 1280 | } else { |
1da177e4 LT |
1281 | struct block_device *whole; |
1282 | whole = bdget_disk(disk, 0); | |
1283 | ret = -ENOMEM; | |
1284 | if (!whole) | |
0762b8bd | 1285 | goto out_clear; |
37be4124 | 1286 | BUG_ON(for_part); |
572c4892 | 1287 | ret = __blkdev_get(whole, mode, 1); |
1da177e4 | 1288 | if (ret) |
0762b8bd | 1289 | goto out_clear; |
1da177e4 | 1290 | bdev->bd_contains = whole; |
89f97496 | 1291 | bdev->bd_part = disk_get_part(disk, partno); |
e71bf0d0 | 1292 | if (!(disk->flags & GENHD_FL_UP) || |
89f97496 | 1293 | !bdev->bd_part || !bdev->bd_part->nr_sects) { |
1da177e4 | 1294 | ret = -ENXIO; |
0762b8bd | 1295 | goto out_clear; |
1da177e4 | 1296 | } |
89f97496 | 1297 | bd_set_size(bdev, (loff_t)bdev->bd_part->nr_sects << 9); |
f0b2e563 JM |
1298 | /* |
1299 | * If the partition is not aligned on a page | |
1300 | * boundary, we can't do dax I/O to it. | |
1301 | */ | |
1302 | if ((bdev->bd_part->start_sect % (PAGE_SIZE / 512)) || | |
1303 | (bdev->bd_part->nr_sects % (PAGE_SIZE / 512))) | |
1304 | bdev->bd_inode->i_flags &= ~S_DAX; | |
1da177e4 | 1305 | } |
791ba932 JK |
1306 | |
1307 | if (bdev->bd_bdi == &noop_backing_dev_info) | |
1308 | bdev->bd_bdi = bdi_get(disk->queue->backing_dev_info); | |
1da177e4 | 1309 | } else { |
1da177e4 | 1310 | if (bdev->bd_contains == bdev) { |
1196f8b8 TH |
1311 | ret = 0; |
1312 | if (bdev->bd_disk->fops->open) | |
572c4892 | 1313 | ret = bdev->bd_disk->fops->open(bdev, mode); |
1196f8b8 | 1314 | /* the same as first opener case, read comment there */ |
fe316bf2 JN |
1315 | if (bdev->bd_invalidated) { |
1316 | if (!ret) | |
1317 | rescan_partitions(bdev->bd_disk, bdev); | |
1318 | else if (ret == -ENOMEDIUM) | |
1319 | invalidate_partitions(bdev->bd_disk, bdev); | |
1320 | } | |
1196f8b8 TH |
1321 | if (ret) |
1322 | goto out_unlock_bdev; | |
1da177e4 | 1323 | } |
69e02c59 | 1324 | /* only one opener holds refs to the module and disk */ |
69e02c59 | 1325 | put_disk(disk); |
523e1d39 | 1326 | module_put(owner); |
1da177e4 LT |
1327 | } |
1328 | bdev->bd_openers++; | |
37be4124 N |
1329 | if (for_part) |
1330 | bdev->bd_part_count++; | |
c039e313 | 1331 | mutex_unlock(&bdev->bd_mutex); |
69e02c59 | 1332 | disk_unblock_events(disk); |
1da177e4 LT |
1333 | return 0; |
1334 | ||
0762b8bd | 1335 | out_clear: |
89f97496 | 1336 | disk_put_part(bdev->bd_part); |
1da177e4 | 1337 | bdev->bd_disk = NULL; |
0762b8bd | 1338 | bdev->bd_part = NULL; |
87192a2a | 1339 | bdev->bd_queue = NULL; |
1da177e4 | 1340 | if (bdev != bdev->bd_contains) |
572c4892 | 1341 | __blkdev_put(bdev->bd_contains, mode, 1); |
1da177e4 | 1342 | bdev->bd_contains = NULL; |
0762b8bd | 1343 | out_unlock_bdev: |
c039e313 | 1344 | mutex_unlock(&bdev->bd_mutex); |
69e02c59 | 1345 | disk_unblock_events(disk); |
0762b8bd | 1346 | put_disk(disk); |
523e1d39 | 1347 | module_put(owner); |
4345caba | 1348 | out: |
0762b8bd TH |
1349 | bdput(bdev); |
1350 | ||
1da177e4 LT |
1351 | return ret; |
1352 | } | |
1353 | ||
d4d77629 TH |
1354 | /** |
1355 | * blkdev_get - open a block device | |
1356 | * @bdev: block_device to open | |
1357 | * @mode: FMODE_* mask | |
1358 | * @holder: exclusive holder identifier | |
1359 | * | |
1360 | * Open @bdev with @mode. If @mode includes %FMODE_EXCL, @bdev is | |
1361 | * open with exclusive access. Specifying %FMODE_EXCL with %NULL | |
1362 | * @holder is invalid. Exclusive opens may nest for the same @holder. | |
1363 | * | |
1364 | * On success, the reference count of @bdev is unchanged. On failure, | |
1365 | * @bdev is put. | |
1366 | * | |
1367 | * CONTEXT: | |
1368 | * Might sleep. | |
1369 | * | |
1370 | * RETURNS: | |
1371 | * 0 on success, -errno on failure. | |
1372 | */ | |
e525fd89 | 1373 | int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder) |
1da177e4 | 1374 | { |
e525fd89 TH |
1375 | struct block_device *whole = NULL; |
1376 | int res; | |
1377 | ||
1378 | WARN_ON_ONCE((mode & FMODE_EXCL) && !holder); | |
1379 | ||
1380 | if ((mode & FMODE_EXCL) && holder) { | |
1381 | whole = bd_start_claiming(bdev, holder); | |
1382 | if (IS_ERR(whole)) { | |
1383 | bdput(bdev); | |
1384 | return PTR_ERR(whole); | |
1385 | } | |
1386 | } | |
1387 | ||
1388 | res = __blkdev_get(bdev, mode, 0); | |
1389 | ||
1390 | if (whole) { | |
d4dc210f TH |
1391 | struct gendisk *disk = whole->bd_disk; |
1392 | ||
6a027eff | 1393 | /* finish claiming */ |
77ea887e | 1394 | mutex_lock(&bdev->bd_mutex); |
6a027eff TH |
1395 | spin_lock(&bdev_lock); |
1396 | ||
77ea887e | 1397 | if (!res) { |
6a027eff TH |
1398 | BUG_ON(!bd_may_claim(bdev, whole, holder)); |
1399 | /* | |
1400 | * Note that for a whole device bd_holders | |
1401 | * will be incremented twice, and bd_holder | |
1402 | * will be set to bd_may_claim before being | |
1403 | * set to holder | |
1404 | */ | |
1405 | whole->bd_holders++; | |
1406 | whole->bd_holder = bd_may_claim; | |
1407 | bdev->bd_holders++; | |
1408 | bdev->bd_holder = holder; | |
1409 | } | |
1410 | ||
1411 | /* tell others that we're done */ | |
1412 | BUG_ON(whole->bd_claiming != holder); | |
1413 | whole->bd_claiming = NULL; | |
1414 | wake_up_bit(&whole->bd_claiming, 0); | |
1415 | ||
1416 | spin_unlock(&bdev_lock); | |
77ea887e TH |
1417 | |
1418 | /* | |
d4dc210f TH |
1419 | * Block event polling for write claims if requested. Any |
1420 | * write holder makes the write_holder state stick until | |
1421 | * all are released. This is good enough and tracking | |
1422 | * individual writeable reference is too fragile given the | |
1423 | * way @mode is used in blkdev_get/put(). | |
77ea887e | 1424 | */ |
4c49ff3f TH |
1425 | if (!res && (mode & FMODE_WRITE) && !bdev->bd_write_holder && |
1426 | (disk->flags & GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE)) { | |
77ea887e | 1427 | bdev->bd_write_holder = true; |
d4dc210f | 1428 | disk_block_events(disk); |
77ea887e TH |
1429 | } |
1430 | ||
1431 | mutex_unlock(&bdev->bd_mutex); | |
6a027eff | 1432 | bdput(whole); |
e525fd89 TH |
1433 | } |
1434 | ||
1435 | return res; | |
37be4124 | 1436 | } |
1da177e4 LT |
1437 | EXPORT_SYMBOL(blkdev_get); |
1438 | ||
d4d77629 TH |
1439 | /** |
1440 | * blkdev_get_by_path - open a block device by name | |
1441 | * @path: path to the block device to open | |
1442 | * @mode: FMODE_* mask | |
1443 | * @holder: exclusive holder identifier | |
1444 | * | |
1445 | * Open the blockdevice described by the device file at @path. @mode | |
1446 | * and @holder are identical to blkdev_get(). | |
1447 | * | |
1448 | * On success, the returned block_device has reference count of one. | |
1449 | * | |
1450 | * CONTEXT: | |
1451 | * Might sleep. | |
1452 | * | |
1453 | * RETURNS: | |
1454 | * Pointer to block_device on success, ERR_PTR(-errno) on failure. | |
1455 | */ | |
1456 | struct block_device *blkdev_get_by_path(const char *path, fmode_t mode, | |
1457 | void *holder) | |
1458 | { | |
1459 | struct block_device *bdev; | |
9a472674 | 1460 | int perm = 0; |
d4d77629 TH |
1461 | int err; |
1462 | ||
9a472674 SF |
1463 | if (mode & FMODE_READ) |
1464 | perm |= MAY_READ; | |
1465 | if (mode & FMODE_WRITE) | |
1466 | perm |= MAY_WRITE; | |
1467 | bdev = lookup_bdev(path, perm); | |
d4d77629 TH |
1468 | if (IS_ERR(bdev)) |
1469 | return bdev; | |
1470 | ||
1471 | err = blkdev_get(bdev, mode, holder); | |
1472 | if (err) | |
1473 | return ERR_PTR(err); | |
1474 | ||
e51900f7 CE |
1475 | if ((mode & FMODE_WRITE) && bdev_read_only(bdev)) { |
1476 | blkdev_put(bdev, mode); | |
1477 | return ERR_PTR(-EACCES); | |
1478 | } | |
1479 | ||
d4d77629 TH |
1480 | return bdev; |
1481 | } | |
1482 | EXPORT_SYMBOL(blkdev_get_by_path); | |
1483 | ||
1484 | /** | |
1485 | * blkdev_get_by_dev - open a block device by device number | |
1486 | * @dev: device number of block device to open | |
1487 | * @mode: FMODE_* mask | |
1488 | * @holder: exclusive holder identifier | |
1489 | * | |
1490 | * Open the blockdevice described by device number @dev. @mode and | |
1491 | * @holder are identical to blkdev_get(). | |
1492 | * | |
1493 | * Use it ONLY if you really do not have anything better - i.e. when | |
1494 | * you are behind a truly sucky interface and all you are given is a | |
1495 | * device number. _Never_ to be used for internal purposes. If you | |
1496 | * ever need it - reconsider your API. | |
1497 | * | |
1498 | * On success, the returned block_device has reference count of one. | |
1499 | * | |
1500 | * CONTEXT: | |
1501 | * Might sleep. | |
1502 | * | |
1503 | * RETURNS: | |
1504 | * Pointer to block_device on success, ERR_PTR(-errno) on failure. | |
1505 | */ | |
1506 | struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder) | |
1507 | { | |
1508 | struct block_device *bdev; | |
1509 | int err; | |
1510 | ||
1511 | bdev = bdget(dev); | |
1512 | if (!bdev) | |
1513 | return ERR_PTR(-ENOMEM); | |
1514 | ||
1515 | err = blkdev_get(bdev, mode, holder); | |
1516 | if (err) | |
1517 | return ERR_PTR(err); | |
1518 | ||
1519 | return bdev; | |
1520 | } | |
1521 | EXPORT_SYMBOL(blkdev_get_by_dev); | |
1522 | ||
1da177e4 LT |
1523 | static int blkdev_open(struct inode * inode, struct file * filp) |
1524 | { | |
1525 | struct block_device *bdev; | |
1da177e4 LT |
1526 | |
1527 | /* | |
1528 | * Preserve backwards compatibility and allow large file access | |
1529 | * even if userspace doesn't ask for it explicitly. Some mkfs | |
1530 | * binary needs it. We might want to drop this workaround | |
1531 | * during an unstable branch. | |
1532 | */ | |
1533 | filp->f_flags |= O_LARGEFILE; | |
1534 | ||
572c4892 AV |
1535 | if (filp->f_flags & O_NDELAY) |
1536 | filp->f_mode |= FMODE_NDELAY; | |
1537 | if (filp->f_flags & O_EXCL) | |
1538 | filp->f_mode |= FMODE_EXCL; | |
1539 | if ((filp->f_flags & O_ACCMODE) == 3) | |
1540 | filp->f_mode |= FMODE_WRITE_IOCTL; | |
1541 | ||
1da177e4 | 1542 | bdev = bd_acquire(inode); |
6a2aae06 PE |
1543 | if (bdev == NULL) |
1544 | return -ENOMEM; | |
1da177e4 | 1545 | |
4de0a612 SF |
1546 | /* |
1547 | * A negative i_writecount for bdev->bd_inode means that the bdev | |
1548 | * or one of its paritions is mounted in a user namespace. Deny | |
1549 | * writing for non-root in this case, otherwise an unprivileged | |
1550 | * user can attack the kernel by modifying the backing store of a | |
1551 | * mounted filesystem. | |
1552 | */ | |
1553 | if ((filp->f_mode & FMODE_WRITE) && | |
1554 | !file_ns_capable(filp, &init_user_ns, CAP_SYS_ADMIN) && | |
1555 | !atomic_inc_unless_negative(&bdev->bd_inode->i_writecount)) { | |
1556 | bdput(bdev); | |
1557 | return -EBUSY; | |
1558 | } | |
1559 | ||
572c4892 AV |
1560 | filp->f_mapping = bdev->bd_inode->i_mapping; |
1561 | ||
e525fd89 | 1562 | return blkdev_get(bdev, filp->f_mode, filp); |
1da177e4 LT |
1563 | } |
1564 | ||
4385bab1 | 1565 | static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part) |
2e7b651d | 1566 | { |
2e7b651d | 1567 | struct gendisk *disk = bdev->bd_disk; |
37be4124 | 1568 | struct block_device *victim = NULL; |
2e7b651d | 1569 | |
6796bf54 | 1570 | mutex_lock_nested(&bdev->bd_mutex, for_part); |
37be4124 N |
1571 | if (for_part) |
1572 | bdev->bd_part_count--; | |
1573 | ||
2e7b651d | 1574 | if (!--bdev->bd_openers) { |
6a027eff | 1575 | WARN_ON_ONCE(bdev->bd_holders); |
2e7b651d PZ |
1576 | sync_blockdev(bdev); |
1577 | kill_bdev(bdev); | |
43d1c0eb ID |
1578 | |
1579 | bdev_write_inode(bdev); | |
2e7b651d PZ |
1580 | } |
1581 | if (bdev->bd_contains == bdev) { | |
1582 | if (disk->fops->release) | |
db2a144b | 1583 | disk->fops->release(disk, mode); |
2e7b651d PZ |
1584 | } |
1585 | if (!bdev->bd_openers) { | |
1586 | struct module *owner = disk->fops->owner; | |
1587 | ||
0762b8bd TH |
1588 | disk_put_part(bdev->bd_part); |
1589 | bdev->bd_part = NULL; | |
2e7b651d | 1590 | bdev->bd_disk = NULL; |
37be4124 N |
1591 | if (bdev != bdev->bd_contains) |
1592 | victim = bdev->bd_contains; | |
2e7b651d | 1593 | bdev->bd_contains = NULL; |
523e1d39 TH |
1594 | |
1595 | put_disk(disk); | |
1596 | module_put(owner); | |
2e7b651d | 1597 | } |
2e7b651d PZ |
1598 | mutex_unlock(&bdev->bd_mutex); |
1599 | bdput(bdev); | |
37be4124 | 1600 | if (victim) |
9a1c3542 | 1601 | __blkdev_put(victim, mode, 1); |
2e7b651d PZ |
1602 | } |
1603 | ||
4385bab1 | 1604 | void blkdev_put(struct block_device *bdev, fmode_t mode) |
37be4124 | 1605 | { |
85ef06d1 TH |
1606 | mutex_lock(&bdev->bd_mutex); |
1607 | ||
e525fd89 | 1608 | if (mode & FMODE_EXCL) { |
6a027eff TH |
1609 | bool bdev_free; |
1610 | ||
1611 | /* | |
1612 | * Release a claim on the device. The holder fields | |
1613 | * are protected with bdev_lock. bd_mutex is to | |
1614 | * synchronize disk_holder unlinking. | |
1615 | */ | |
6a027eff TH |
1616 | spin_lock(&bdev_lock); |
1617 | ||
1618 | WARN_ON_ONCE(--bdev->bd_holders < 0); | |
1619 | WARN_ON_ONCE(--bdev->bd_contains->bd_holders < 0); | |
1620 | ||
1621 | /* bd_contains might point to self, check in a separate step */ | |
1622 | if ((bdev_free = !bdev->bd_holders)) | |
1623 | bdev->bd_holder = NULL; | |
1624 | if (!bdev->bd_contains->bd_holders) | |
1625 | bdev->bd_contains->bd_holder = NULL; | |
1626 | ||
1627 | spin_unlock(&bdev_lock); | |
1628 | ||
77ea887e TH |
1629 | /* |
1630 | * If this was the last claim, remove holder link and | |
1631 | * unblock evpoll if it was a write holder. | |
1632 | */ | |
85ef06d1 TH |
1633 | if (bdev_free && bdev->bd_write_holder) { |
1634 | disk_unblock_events(bdev->bd_disk); | |
1635 | bdev->bd_write_holder = false; | |
77ea887e | 1636 | } |
6936217c | 1637 | } |
77ea887e | 1638 | |
85ef06d1 TH |
1639 | /* |
1640 | * Trigger event checking and tell drivers to flush MEDIA_CHANGE | |
1641 | * event. This is to ensure detection of media removal commanded | |
1642 | * from userland - e.g. eject(1). | |
1643 | */ | |
1644 | disk_flush_events(bdev->bd_disk, DISK_EVENT_MEDIA_CHANGE); | |
1645 | ||
1646 | mutex_unlock(&bdev->bd_mutex); | |
1647 | ||
4385bab1 | 1648 | __blkdev_put(bdev, mode, 0); |
37be4124 | 1649 | } |
2e7b651d PZ |
1650 | EXPORT_SYMBOL(blkdev_put); |
1651 | ||
1da177e4 LT |
1652 | static int blkdev_close(struct inode * inode, struct file * filp) |
1653 | { | |
1654 | struct block_device *bdev = I_BDEV(filp->f_mapping->host); | |
4de0a612 SF |
1655 | if (filp->f_mode & FMODE_WRITE && |
1656 | !file_ns_capable(filp, &init_user_ns, CAP_SYS_ADMIN)) | |
1657 | atomic_dec(&bdev->bd_inode->i_writecount); | |
4385bab1 AV |
1658 | blkdev_put(bdev, filp->f_mode); |
1659 | return 0; | |
1da177e4 LT |
1660 | } |
1661 | ||
bb93e3a5 | 1662 | static long block_ioctl(struct file *file, unsigned cmd, unsigned long arg) |
1da177e4 | 1663 | { |
56b26add AV |
1664 | struct block_device *bdev = I_BDEV(file->f_mapping->host); |
1665 | fmode_t mode = file->f_mode; | |
fd4ce1ac CH |
1666 | |
1667 | /* | |
1668 | * O_NDELAY can be altered using fcntl(.., F_SETFL, ..), so we have | |
1669 | * to updated it before every ioctl. | |
1670 | */ | |
56b26add | 1671 | if (file->f_flags & O_NDELAY) |
fd4ce1ac CH |
1672 | mode |= FMODE_NDELAY; |
1673 | else | |
1674 | mode &= ~FMODE_NDELAY; | |
1675 | ||
56b26add | 1676 | return blkdev_ioctl(bdev, mode, cmd, arg); |
1da177e4 LT |
1677 | } |
1678 | ||
eef99380 CH |
1679 | /* |
1680 | * Write data to the block device. Only intended for the block device itself | |
1681 | * and the raw driver which basically is a fake block device. | |
1682 | * | |
1683 | * Does not take i_mutex for the write and thus is not for general purpose | |
1684 | * use. | |
1685 | */ | |
1456c0a8 | 1686 | ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from) |
eef99380 CH |
1687 | { |
1688 | struct file *file = iocb->ki_filp; | |
7ec7b94a AV |
1689 | struct inode *bd_inode = file->f_mapping->host; |
1690 | loff_t size = i_size_read(bd_inode); | |
53362a05 | 1691 | struct blk_plug plug; |
eef99380 | 1692 | ssize_t ret; |
5f380c7f | 1693 | |
7ec7b94a AV |
1694 | if (bdev_read_only(I_BDEV(bd_inode))) |
1695 | return -EPERM; | |
5f380c7f | 1696 | |
7ec7b94a | 1697 | if (!iov_iter_count(from)) |
5f380c7f AV |
1698 | return 0; |
1699 | ||
7ec7b94a AV |
1700 | if (iocb->ki_pos >= size) |
1701 | return -ENOSPC; | |
1702 | ||
1703 | iov_iter_truncate(from, size - iocb->ki_pos); | |
eef99380 | 1704 | |
53362a05 | 1705 | blk_start_plug(&plug); |
1456c0a8 | 1706 | ret = __generic_file_write_iter(iocb, from); |
02afc27f | 1707 | if (ret > 0) { |
eef99380 | 1708 | ssize_t err; |
1456c0a8 | 1709 | err = generic_write_sync(file, iocb->ki_pos - ret, ret); |
45d4f855 | 1710 | if (err < 0) |
eef99380 CH |
1711 | ret = err; |
1712 | } | |
53362a05 | 1713 | blk_finish_plug(&plug); |
eef99380 CH |
1714 | return ret; |
1715 | } | |
1456c0a8 | 1716 | EXPORT_SYMBOL_GPL(blkdev_write_iter); |
eef99380 | 1717 | |
b2de525f | 1718 | ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to) |
684c9aae LT |
1719 | { |
1720 | struct file *file = iocb->ki_filp; | |
1721 | struct inode *bd_inode = file->f_mapping->host; | |
1722 | loff_t size = i_size_read(bd_inode); | |
a886038b | 1723 | loff_t pos = iocb->ki_pos; |
684c9aae LT |
1724 | |
1725 | if (pos >= size) | |
1726 | return 0; | |
1727 | ||
1728 | size -= pos; | |
a886038b AV |
1729 | iov_iter_truncate(to, size); |
1730 | return generic_file_read_iter(iocb, to); | |
684c9aae | 1731 | } |
b2de525f | 1732 | EXPORT_SYMBOL_GPL(blkdev_read_iter); |
684c9aae | 1733 | |
87d8fe1e TT |
1734 | /* |
1735 | * Try to release a page associated with block device when the system | |
1736 | * is under memory pressure. | |
1737 | */ | |
1738 | static int blkdev_releasepage(struct page *page, gfp_t wait) | |
1739 | { | |
1740 | struct super_block *super = BDEV_I(page->mapping->host)->bdev.bd_super; | |
1741 | ||
1742 | if (super && super->s_op->bdev_try_to_free_page) | |
1743 | return super->s_op->bdev_try_to_free_page(super, page, wait); | |
1744 | ||
1745 | return try_to_free_buffers(page); | |
1746 | } | |
1747 | ||
4c54ac62 | 1748 | static const struct address_space_operations def_blk_aops = { |
1da177e4 | 1749 | .readpage = blkdev_readpage, |
447f05bb | 1750 | .readpages = blkdev_readpages, |
1da177e4 | 1751 | .writepage = blkdev_writepage, |
6272b5a5 NP |
1752 | .write_begin = blkdev_write_begin, |
1753 | .write_end = blkdev_write_end, | |
1da177e4 | 1754 | .writepages = generic_writepages, |
87d8fe1e | 1755 | .releasepage = blkdev_releasepage, |
1da177e4 | 1756 | .direct_IO = blkdev_direct_IO, |
b4597226 | 1757 | .is_dirty_writeback = buffer_check_dirty_writeback, |
1da177e4 LT |
1758 | }; |
1759 | ||
4b6f5d20 | 1760 | const struct file_operations def_blk_fops = { |
1da177e4 LT |
1761 | .open = blkdev_open, |
1762 | .release = blkdev_close, | |
1763 | .llseek = block_llseek, | |
a886038b | 1764 | .read_iter = blkdev_read_iter, |
1456c0a8 | 1765 | .write_iter = blkdev_write_iter, |
1e8b3332 | 1766 | .mmap = generic_file_mmap, |
b1dd3b28 | 1767 | .fsync = blkdev_fsync, |
bb93e3a5 | 1768 | .unlocked_ioctl = block_ioctl, |
1da177e4 LT |
1769 | #ifdef CONFIG_COMPAT |
1770 | .compat_ioctl = compat_blkdev_ioctl, | |
1771 | #endif | |
1e8b3332 | 1772 | .splice_read = generic_file_splice_read, |
8d020765 | 1773 | .splice_write = iter_file_splice_write, |
1da177e4 LT |
1774 | }; |
1775 | ||
1776 | int ioctl_by_bdev(struct block_device *bdev, unsigned cmd, unsigned long arg) | |
1777 | { | |
1778 | int res; | |
1779 | mm_segment_t old_fs = get_fs(); | |
1780 | set_fs(KERNEL_DS); | |
56b26add | 1781 | res = blkdev_ioctl(bdev, 0, cmd, arg); |
1da177e4 LT |
1782 | set_fs(old_fs); |
1783 | return res; | |
1784 | } | |
1785 | ||
1786 | EXPORT_SYMBOL(ioctl_by_bdev); | |
1787 | ||
1788 | /** | |
1789 | * lookup_bdev - lookup a struct block_device by name | |
94e2959e | 1790 | * @pathname: special file representing the block device |
4a959886 | 1791 | * @mask: rights to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC) |
1da177e4 | 1792 | * |
57d1b536 | 1793 | * Get a reference to the blockdevice at @pathname in the current |
1da177e4 | 1794 | * namespace if possible and return it. Return ERR_PTR(error) |
4a959886 SF |
1795 | * otherwise. If @mask is non-zero, check for access rights to the |
1796 | * inode at @pathname. | |
1da177e4 | 1797 | */ |
4a959886 | 1798 | struct block_device *lookup_bdev(const char *pathname, int mask) |
1da177e4 LT |
1799 | { |
1800 | struct block_device *bdev; | |
1801 | struct inode *inode; | |
421748ec | 1802 | struct path path; |
1da177e4 LT |
1803 | int error; |
1804 | ||
421748ec | 1805 | if (!pathname || !*pathname) |
1da177e4 LT |
1806 | return ERR_PTR(-EINVAL); |
1807 | ||
421748ec | 1808 | error = kern_path(pathname, LOOKUP_FOLLOW, &path); |
1da177e4 LT |
1809 | if (error) |
1810 | return ERR_PTR(error); | |
1811 | ||
bb668734 | 1812 | inode = d_backing_inode(path.dentry); |
4a959886 SF |
1813 | if (mask != 0 && !capable(CAP_SYS_ADMIN)) { |
1814 | error = __inode_permission(inode, mask); | |
1815 | if (error) | |
1816 | goto fail; | |
1817 | } | |
1da177e4 LT |
1818 | error = -ENOTBLK; |
1819 | if (!S_ISBLK(inode->i_mode)) | |
1820 | goto fail; | |
1821 | error = -EACCES; | |
421748ec | 1822 | if (path.mnt->mnt_flags & MNT_NODEV) |
1da177e4 LT |
1823 | goto fail; |
1824 | error = -ENOMEM; | |
1825 | bdev = bd_acquire(inode); | |
1826 | if (!bdev) | |
1827 | goto fail; | |
1828 | out: | |
421748ec | 1829 | path_put(&path); |
1da177e4 LT |
1830 | return bdev; |
1831 | fail: | |
1832 | bdev = ERR_PTR(error); | |
1833 | goto out; | |
1834 | } | |
d5686b44 | 1835 | EXPORT_SYMBOL(lookup_bdev); |
1da177e4 | 1836 | |
93b270f7 | 1837 | int __invalidate_device(struct block_device *bdev, bool kill_dirty) |
b71e8a4c DH |
1838 | { |
1839 | struct super_block *sb = get_super(bdev); | |
1840 | int res = 0; | |
1841 | ||
1842 | if (sb) { | |
1843 | /* | |
1844 | * no need to lock the super, get_super holds the | |
1845 | * read mutex so the filesystem cannot go away | |
1846 | * under us (->put_super runs with the write lock | |
1847 | * hold). | |
1848 | */ | |
1849 | shrink_dcache_sb(sb); | |
93b270f7 | 1850 | res = invalidate_inodes(sb, kill_dirty); |
b71e8a4c DH |
1851 | drop_super(sb); |
1852 | } | |
f98393a6 | 1853 | invalidate_bdev(bdev); |
b71e8a4c DH |
1854 | return res; |
1855 | } | |
1856 | EXPORT_SYMBOL(__invalidate_device); | |
5c0d6b60 JK |
1857 | |
1858 | void iterate_bdevs(void (*func)(struct block_device *, void *), void *arg) | |
1859 | { | |
1860 | struct inode *inode, *old_inode = NULL; | |
1861 | ||
74278da9 | 1862 | spin_lock(&blockdev_superblock->s_inode_list_lock); |
5c0d6b60 JK |
1863 | list_for_each_entry(inode, &blockdev_superblock->s_inodes, i_sb_list) { |
1864 | struct address_space *mapping = inode->i_mapping; | |
c166dcaf | 1865 | struct block_device *bdev; |
5c0d6b60 JK |
1866 | |
1867 | spin_lock(&inode->i_lock); | |
1868 | if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW) || | |
1869 | mapping->nrpages == 0) { | |
1870 | spin_unlock(&inode->i_lock); | |
1871 | continue; | |
1872 | } | |
1873 | __iget(inode); | |
1874 | spin_unlock(&inode->i_lock); | |
74278da9 | 1875 | spin_unlock(&blockdev_superblock->s_inode_list_lock); |
5c0d6b60 JK |
1876 | /* |
1877 | * We hold a reference to 'inode' so it couldn't have been | |
1878 | * removed from s_inodes list while we dropped the | |
74278da9 | 1879 | * s_inode_list_lock We cannot iput the inode now as we can |
5c0d6b60 | 1880 | * be holding the last reference and we cannot iput it under |
74278da9 | 1881 | * s_inode_list_lock. So we keep the reference and iput it |
5c0d6b60 JK |
1882 | * later. |
1883 | */ | |
1884 | iput(old_inode); | |
1885 | old_inode = inode; | |
c166dcaf | 1886 | bdev = I_BDEV(inode); |
5c0d6b60 | 1887 | |
c166dcaf RV |
1888 | mutex_lock(&bdev->bd_mutex); |
1889 | if (bdev->bd_openers) | |
1890 | func(bdev, arg); | |
1891 | mutex_unlock(&bdev->bd_mutex); | |
5c0d6b60 | 1892 | |
74278da9 | 1893 | spin_lock(&blockdev_superblock->s_inode_list_lock); |
5c0d6b60 | 1894 | } |
74278da9 | 1895 | spin_unlock(&blockdev_superblock->s_inode_list_lock); |
5c0d6b60 JK |
1896 | iput(old_inode); |
1897 | } |