Commit | Line | Data |
---|---|---|
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 | ||
2af3a815 TK |
53 | void __vfs_msg(struct super_block *sb, const char *prefix, const char *fmt, ...) |
54 | { | |
55 | struct va_format vaf; | |
56 | va_list args; | |
57 | ||
58 | va_start(args, fmt); | |
59 | vaf.fmt = fmt; | |
60 | vaf.va = &args; | |
61 | printk_ratelimited("%sVFS (%s): %pV\n", prefix, sb->s_id, &vaf); | |
62 | va_end(args); | |
63 | } | |
64 | ||
dbd3ca50 | 65 | static void bdev_write_inode(struct block_device *bdev) |
564f00f6 | 66 | { |
dbd3ca50 VG |
67 | struct inode *inode = bdev->bd_inode; |
68 | int ret; | |
69 | ||
564f00f6 CH |
70 | spin_lock(&inode->i_lock); |
71 | while (inode->i_state & I_DIRTY) { | |
72 | spin_unlock(&inode->i_lock); | |
dbd3ca50 VG |
73 | ret = write_inode_now(inode, true); |
74 | if (ret) { | |
75 | char name[BDEVNAME_SIZE]; | |
76 | pr_warn_ratelimited("VFS: Dirty inode writeback failed " | |
77 | "for block device %s (err=%d).\n", | |
78 | bdevname(bdev, name), ret); | |
79 | } | |
564f00f6 CH |
80 | spin_lock(&inode->i_lock); |
81 | } | |
82 | spin_unlock(&inode->i_lock); | |
83 | } | |
84 | ||
f9a14399 | 85 | /* Kill _all_ buffers and pagecache , dirty or not.. */ |
ff01bb48 | 86 | void kill_bdev(struct block_device *bdev) |
1da177e4 | 87 | { |
ff01bb48 AV |
88 | struct address_space *mapping = bdev->bd_inode->i_mapping; |
89 | ||
f9fe48be | 90 | if (mapping->nrpages == 0 && mapping->nrexceptional == 0) |
f9a14399 | 91 | return; |
ff01bb48 | 92 | |
f9a14399 | 93 | invalidate_bh_lrus(); |
ff01bb48 | 94 | truncate_inode_pages(mapping, 0); |
1da177e4 | 95 | } |
ff01bb48 AV |
96 | EXPORT_SYMBOL(kill_bdev); |
97 | ||
98 | /* Invalidate clean unused buffers and pagecache. */ | |
99 | void invalidate_bdev(struct block_device *bdev) | |
100 | { | |
101 | struct address_space *mapping = bdev->bd_inode->i_mapping; | |
102 | ||
103 | if (mapping->nrpages == 0) | |
104 | return; | |
105 | ||
106 | invalidate_bh_lrus(); | |
107 | lru_add_drain_all(); /* make sure all lru add caches are flushed */ | |
108 | invalidate_mapping_pages(mapping, 0, -1); | |
109 | /* 99% of the time, we don't need to flush the cleancache on the bdev. | |
110 | * But, for the strange corners, lets be cautious | |
111 | */ | |
3167760f | 112 | cleancache_invalidate_inode(mapping); |
ff01bb48 AV |
113 | } |
114 | EXPORT_SYMBOL(invalidate_bdev); | |
1da177e4 LT |
115 | |
116 | int set_blocksize(struct block_device *bdev, int size) | |
117 | { | |
118 | /* Size must be a power of two, and between 512 and PAGE_SIZE */ | |
1368c4f2 | 119 | if (size > PAGE_SIZE || size < 512 || !is_power_of_2(size)) |
1da177e4 LT |
120 | return -EINVAL; |
121 | ||
122 | /* Size cannot be smaller than the size supported by the device */ | |
e1defc4f | 123 | if (size < bdev_logical_block_size(bdev)) |
1da177e4 LT |
124 | return -EINVAL; |
125 | ||
126 | /* Don't change the size if it is same as current */ | |
127 | if (bdev->bd_block_size != size) { | |
128 | sync_blockdev(bdev); | |
129 | bdev->bd_block_size = size; | |
130 | bdev->bd_inode->i_blkbits = blksize_bits(size); | |
131 | kill_bdev(bdev); | |
132 | } | |
133 | return 0; | |
134 | } | |
135 | ||
136 | EXPORT_SYMBOL(set_blocksize); | |
137 | ||
138 | int sb_set_blocksize(struct super_block *sb, int size) | |
139 | { | |
1da177e4 LT |
140 | if (set_blocksize(sb->s_bdev, size)) |
141 | return 0; | |
142 | /* If we get here, we know size is power of two | |
143 | * and it's value is between 512 and PAGE_SIZE */ | |
144 | sb->s_blocksize = size; | |
38885bd4 | 145 | sb->s_blocksize_bits = blksize_bits(size); |
1da177e4 LT |
146 | return sb->s_blocksize; |
147 | } | |
148 | ||
149 | EXPORT_SYMBOL(sb_set_blocksize); | |
150 | ||
151 | int sb_min_blocksize(struct super_block *sb, int size) | |
152 | { | |
e1defc4f | 153 | int minsize = bdev_logical_block_size(sb->s_bdev); |
1da177e4 LT |
154 | if (size < minsize) |
155 | size = minsize; | |
156 | return sb_set_blocksize(sb, size); | |
157 | } | |
158 | ||
159 | EXPORT_SYMBOL(sb_min_blocksize); | |
160 | ||
161 | static int | |
162 | blkdev_get_block(struct inode *inode, sector_t iblock, | |
163 | struct buffer_head *bh, int create) | |
164 | { | |
1da177e4 LT |
165 | bh->b_bdev = I_BDEV(inode); |
166 | bh->b_blocknr = iblock; | |
167 | set_buffer_mapped(bh); | |
168 | return 0; | |
169 | } | |
170 | ||
4ebb16ca DW |
171 | static struct inode *bdev_file_inode(struct file *file) |
172 | { | |
173 | return file->f_mapping->host; | |
174 | } | |
175 | ||
b2e895db | 176 | static ssize_t |
22c6186e | 177 | blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, loff_t offset) |
b2e895db AM |
178 | { |
179 | struct file *file = iocb->ki_filp; | |
4ebb16ca | 180 | struct inode *inode = bdev_file_inode(file); |
b2e895db | 181 | |
bbab37dd MW |
182 | if (IS_DAX(inode)) |
183 | return dax_do_io(iocb, inode, iter, offset, blkdev_get_block, | |
184 | NULL, DIO_SKIP_DIO_COUNT); | |
17f8c842 | 185 | return __blockdev_direct_IO(iocb, inode, I_BDEV(inode), iter, offset, |
fe0f07d0 JA |
186 | blkdev_get_block, NULL, NULL, |
187 | DIO_SKIP_DIO_COUNT); | |
b2e895db AM |
188 | } |
189 | ||
5cee5815 JK |
190 | int __sync_blockdev(struct block_device *bdev, int wait) |
191 | { | |
192 | if (!bdev) | |
193 | return 0; | |
194 | if (!wait) | |
195 | return filemap_flush(bdev->bd_inode->i_mapping); | |
196 | return filemap_write_and_wait(bdev->bd_inode->i_mapping); | |
197 | } | |
198 | ||
585d3bc0 NP |
199 | /* |
200 | * Write out and wait upon all the dirty data associated with a block | |
201 | * device via its mapping. Does not take the superblock lock. | |
202 | */ | |
203 | int sync_blockdev(struct block_device *bdev) | |
204 | { | |
5cee5815 | 205 | return __sync_blockdev(bdev, 1); |
585d3bc0 NP |
206 | } |
207 | EXPORT_SYMBOL(sync_blockdev); | |
208 | ||
209 | /* | |
210 | * Write out and wait upon all dirty data associated with this | |
211 | * device. Filesystem data as well as the underlying block | |
212 | * device. Takes the superblock lock. | |
213 | */ | |
214 | int fsync_bdev(struct block_device *bdev) | |
215 | { | |
216 | struct super_block *sb = get_super(bdev); | |
217 | if (sb) { | |
60b0680f | 218 | int res = sync_filesystem(sb); |
585d3bc0 NP |
219 | drop_super(sb); |
220 | return res; | |
221 | } | |
222 | return sync_blockdev(bdev); | |
223 | } | |
47e4491b | 224 | EXPORT_SYMBOL(fsync_bdev); |
585d3bc0 NP |
225 | |
226 | /** | |
227 | * freeze_bdev -- lock a filesystem and force it into a consistent state | |
228 | * @bdev: blockdevice to lock | |
229 | * | |
585d3bc0 NP |
230 | * If a superblock is found on this device, we take the s_umount semaphore |
231 | * on it to make sure nobody unmounts until the snapshot creation is done. | |
232 | * The reference counter (bd_fsfreeze_count) guarantees that only the last | |
233 | * unfreeze process can unfreeze the frozen filesystem actually when multiple | |
234 | * freeze requests arrive simultaneously. It counts up in freeze_bdev() and | |
235 | * count down in thaw_bdev(). When it becomes 0, thaw_bdev() will unfreeze | |
236 | * actually. | |
237 | */ | |
238 | struct super_block *freeze_bdev(struct block_device *bdev) | |
239 | { | |
240 | struct super_block *sb; | |
241 | int error = 0; | |
242 | ||
243 | mutex_lock(&bdev->bd_fsfreeze_mutex); | |
4504230a CH |
244 | if (++bdev->bd_fsfreeze_count > 1) { |
245 | /* | |
246 | * We don't even need to grab a reference - the first call | |
247 | * to freeze_bdev grab an active reference and only the last | |
248 | * thaw_bdev drops it. | |
249 | */ | |
585d3bc0 | 250 | sb = get_super(bdev); |
4504230a CH |
251 | drop_super(sb); |
252 | mutex_unlock(&bdev->bd_fsfreeze_mutex); | |
253 | return sb; | |
254 | } | |
255 | ||
256 | sb = get_active_super(bdev); | |
257 | if (!sb) | |
258 | goto out; | |
48b6bca6 BM |
259 | if (sb->s_op->freeze_super) |
260 | error = sb->s_op->freeze_super(sb); | |
261 | else | |
262 | error = freeze_super(sb); | |
18e9e510 JB |
263 | if (error) { |
264 | deactivate_super(sb); | |
265 | bdev->bd_fsfreeze_count--; | |
585d3bc0 | 266 | mutex_unlock(&bdev->bd_fsfreeze_mutex); |
18e9e510 | 267 | return ERR_PTR(error); |
585d3bc0 | 268 | } |
18e9e510 | 269 | deactivate_super(sb); |
4504230a | 270 | out: |
585d3bc0 NP |
271 | sync_blockdev(bdev); |
272 | mutex_unlock(&bdev->bd_fsfreeze_mutex); | |
4fadd7bb | 273 | return sb; /* thaw_bdev releases s->s_umount */ |
585d3bc0 NP |
274 | } |
275 | EXPORT_SYMBOL(freeze_bdev); | |
276 | ||
277 | /** | |
278 | * thaw_bdev -- unlock filesystem | |
279 | * @bdev: blockdevice to unlock | |
280 | * @sb: associated superblock | |
281 | * | |
282 | * Unlocks the filesystem and marks it writeable again after freeze_bdev(). | |
283 | */ | |
284 | int thaw_bdev(struct block_device *bdev, struct super_block *sb) | |
285 | { | |
4504230a | 286 | int error = -EINVAL; |
585d3bc0 NP |
287 | |
288 | mutex_lock(&bdev->bd_fsfreeze_mutex); | |
4504230a | 289 | if (!bdev->bd_fsfreeze_count) |
18e9e510 | 290 | goto out; |
4504230a CH |
291 | |
292 | error = 0; | |
293 | if (--bdev->bd_fsfreeze_count > 0) | |
18e9e510 | 294 | goto out; |
4504230a CH |
295 | |
296 | if (!sb) | |
18e9e510 | 297 | goto out; |
4504230a | 298 | |
48b6bca6 BM |
299 | if (sb->s_op->thaw_super) |
300 | error = sb->s_op->thaw_super(sb); | |
301 | else | |
302 | error = thaw_super(sb); | |
18e9e510 JB |
303 | if (error) { |
304 | bdev->bd_fsfreeze_count++; | |
305 | mutex_unlock(&bdev->bd_fsfreeze_mutex); | |
306 | return error; | |
307 | } | |
308 | out: | |
585d3bc0 NP |
309 | mutex_unlock(&bdev->bd_fsfreeze_mutex); |
310 | return 0; | |
311 | } | |
312 | EXPORT_SYMBOL(thaw_bdev); | |
313 | ||
1da177e4 LT |
314 | static int blkdev_writepage(struct page *page, struct writeback_control *wbc) |
315 | { | |
316 | return block_write_full_page(page, blkdev_get_block, wbc); | |
317 | } | |
318 | ||
319 | static int blkdev_readpage(struct file * file, struct page * page) | |
320 | { | |
321 | return block_read_full_page(page, blkdev_get_block); | |
322 | } | |
323 | ||
447f05bb AM |
324 | static int blkdev_readpages(struct file *file, struct address_space *mapping, |
325 | struct list_head *pages, unsigned nr_pages) | |
326 | { | |
327 | return mpage_readpages(mapping, pages, nr_pages, blkdev_get_block); | |
328 | } | |
329 | ||
6272b5a5 NP |
330 | static int blkdev_write_begin(struct file *file, struct address_space *mapping, |
331 | loff_t pos, unsigned len, unsigned flags, | |
332 | struct page **pagep, void **fsdata) | |
1da177e4 | 333 | { |
155130a4 CH |
334 | return block_write_begin(mapping, pos, len, flags, pagep, |
335 | blkdev_get_block); | |
1da177e4 LT |
336 | } |
337 | ||
6272b5a5 NP |
338 | static int blkdev_write_end(struct file *file, struct address_space *mapping, |
339 | loff_t pos, unsigned len, unsigned copied, | |
340 | struct page *page, void *fsdata) | |
1da177e4 | 341 | { |
6272b5a5 NP |
342 | int ret; |
343 | ret = block_write_end(file, mapping, pos, len, copied, page, fsdata); | |
344 | ||
345 | unlock_page(page); | |
09cbfeaf | 346 | put_page(page); |
6272b5a5 NP |
347 | |
348 | return ret; | |
1da177e4 LT |
349 | } |
350 | ||
351 | /* | |
352 | * private llseek: | |
496ad9aa | 353 | * for a block special file file_inode(file)->i_size is zero |
1da177e4 LT |
354 | * so we compute the size by hand (just as in block_read/write above) |
355 | */ | |
965c8e59 | 356 | static loff_t block_llseek(struct file *file, loff_t offset, int whence) |
1da177e4 | 357 | { |
4ebb16ca | 358 | struct inode *bd_inode = bdev_file_inode(file); |
1da177e4 LT |
359 | loff_t retval; |
360 | ||
5955102c | 361 | inode_lock(bd_inode); |
5d48f3a2 | 362 | retval = fixed_size_llseek(file, offset, whence, i_size_read(bd_inode)); |
5955102c | 363 | inode_unlock(bd_inode); |
1da177e4 LT |
364 | return retval; |
365 | } | |
366 | ||
02c24a82 | 367 | int blkdev_fsync(struct file *filp, loff_t start, loff_t end, int datasync) |
1da177e4 | 368 | { |
4ebb16ca | 369 | struct inode *bd_inode = bdev_file_inode(filp); |
b8af67e2 | 370 | struct block_device *bdev = I_BDEV(bd_inode); |
ab0a9735 | 371 | int error; |
da5aa861 RW |
372 | |
373 | error = filemap_write_and_wait_range(filp->f_mapping, start, end); | |
374 | if (error) | |
375 | return error; | |
ab0a9735 | 376 | |
b8af67e2 AB |
377 | /* |
378 | * There is no need to serialise calls to blkdev_issue_flush with | |
379 | * i_mutex and doing so causes performance issues with concurrent | |
380 | * O_SYNC writers to a block device. | |
381 | */ | |
dd3932ed | 382 | error = blkdev_issue_flush(bdev, GFP_KERNEL, NULL); |
ab0a9735 CH |
383 | if (error == -EOPNOTSUPP) |
384 | error = 0; | |
b8af67e2 | 385 | |
ab0a9735 | 386 | return error; |
1da177e4 | 387 | } |
b1dd3b28 | 388 | EXPORT_SYMBOL(blkdev_fsync); |
1da177e4 | 389 | |
47a191fd MW |
390 | /** |
391 | * bdev_read_page() - Start reading a page from a block device | |
392 | * @bdev: The device to read the page from | |
393 | * @sector: The offset on the device to read the page to (need not be aligned) | |
394 | * @page: The page to read | |
395 | * | |
396 | * On entry, the page should be locked. It will be unlocked when the page | |
397 | * has been read. If the block driver implements rw_page synchronously, | |
398 | * that will be true on exit from this function, but it need not be. | |
399 | * | |
400 | * Errors returned by this function are usually "soft", eg out of memory, or | |
401 | * queue full; callers should try a different route to read this page rather | |
402 | * than propagate an error back up the stack. | |
403 | * | |
404 | * Return: negative errno if an error occurs, 0 if submission was successful. | |
405 | */ | |
406 | int bdev_read_page(struct block_device *bdev, sector_t sector, | |
407 | struct page *page) | |
408 | { | |
409 | const struct block_device_operations *ops = bdev->bd_disk->fops; | |
2e6edc95 DW |
410 | int result = -EOPNOTSUPP; |
411 | ||
f68eb1e7 | 412 | if (!ops->rw_page || bdev_get_integrity(bdev)) |
2e6edc95 DW |
413 | return result; |
414 | ||
6f3b0e8b | 415 | result = blk_queue_enter(bdev->bd_queue, false); |
2e6edc95 DW |
416 | if (result) |
417 | return result; | |
418 | result = ops->rw_page(bdev, sector + get_start_sect(bdev), page, READ); | |
419 | blk_queue_exit(bdev->bd_queue); | |
420 | return result; | |
47a191fd MW |
421 | } |
422 | EXPORT_SYMBOL_GPL(bdev_read_page); | |
423 | ||
424 | /** | |
425 | * bdev_write_page() - Start writing a page to a block device | |
426 | * @bdev: The device to write the page to | |
427 | * @sector: The offset on the device to write the page to (need not be aligned) | |
428 | * @page: The page to write | |
429 | * @wbc: The writeback_control for the write | |
430 | * | |
431 | * On entry, the page should be locked and not currently under writeback. | |
432 | * On exit, if the write started successfully, the page will be unlocked and | |
433 | * under writeback. If the write failed already (eg the driver failed to | |
434 | * queue the page to the device), the page will still be locked. If the | |
435 | * caller is a ->writepage implementation, it will need to unlock the page. | |
436 | * | |
437 | * Errors returned by this function are usually "soft", eg out of memory, or | |
438 | * queue full; callers should try a different route to write this page rather | |
439 | * than propagate an error back up the stack. | |
440 | * | |
441 | * Return: negative errno if an error occurs, 0 if submission was successful. | |
442 | */ | |
443 | int bdev_write_page(struct block_device *bdev, sector_t sector, | |
444 | struct page *page, struct writeback_control *wbc) | |
445 | { | |
446 | int result; | |
447 | int rw = (wbc->sync_mode == WB_SYNC_ALL) ? WRITE_SYNC : WRITE; | |
448 | const struct block_device_operations *ops = bdev->bd_disk->fops; | |
2e6edc95 | 449 | |
f68eb1e7 | 450 | if (!ops->rw_page || bdev_get_integrity(bdev)) |
47a191fd | 451 | return -EOPNOTSUPP; |
6f3b0e8b | 452 | result = blk_queue_enter(bdev->bd_queue, false); |
2e6edc95 DW |
453 | if (result) |
454 | return result; | |
455 | ||
47a191fd MW |
456 | set_page_writeback(page); |
457 | result = ops->rw_page(bdev, sector + get_start_sect(bdev), page, rw); | |
458 | if (result) | |
459 | end_page_writeback(page); | |
460 | else | |
461 | unlock_page(page); | |
2e6edc95 | 462 | blk_queue_exit(bdev->bd_queue); |
47a191fd MW |
463 | return result; |
464 | } | |
465 | EXPORT_SYMBOL_GPL(bdev_write_page); | |
466 | ||
dd22f551 MW |
467 | /** |
468 | * bdev_direct_access() - Get the address for directly-accessibly memory | |
469 | * @bdev: The device containing the memory | |
b2e0d162 | 470 | * @dax: control and output parameters for ->direct_access |
dd22f551 MW |
471 | * |
472 | * If a block device is made up of directly addressable memory, this function | |
473 | * will tell the caller the PFN and the address of the memory. The address | |
474 | * may be directly dereferenced within the kernel without the need to call | |
475 | * ioremap(), kmap() or similar. The PFN is suitable for inserting into | |
476 | * page tables. | |
477 | * | |
478 | * Return: negative errno if an error occurs, otherwise the number of bytes | |
479 | * accessible at this address. | |
480 | */ | |
b2e0d162 | 481 | long bdev_direct_access(struct block_device *bdev, struct blk_dax_ctl *dax) |
dd22f551 | 482 | { |
b2e0d162 DW |
483 | sector_t sector = dax->sector; |
484 | long avail, size = dax->size; | |
dd22f551 MW |
485 | const struct block_device_operations *ops = bdev->bd_disk->fops; |
486 | ||
43c3dd08 MW |
487 | /* |
488 | * The device driver is allowed to sleep, in order to make the | |
489 | * memory directly accessible. | |
490 | */ | |
491 | might_sleep(); | |
492 | ||
dd22f551 MW |
493 | if (size < 0) |
494 | return size; | |
495 | if (!ops->direct_access) | |
496 | return -EOPNOTSUPP; | |
497 | if ((sector + DIV_ROUND_UP(size, 512)) > | |
498 | part_nr_sects_read(bdev->bd_part)) | |
499 | return -ERANGE; | |
500 | sector += get_start_sect(bdev); | |
501 | if (sector % (PAGE_SIZE / 512)) | |
502 | return -EINVAL; | |
b2e0d162 | 503 | avail = ops->direct_access(bdev, sector, &dax->addr, &dax->pfn); |
dd22f551 MW |
504 | if (!avail) |
505 | return -ERANGE; | |
fe683ada DW |
506 | if (avail > 0 && avail & ~PAGE_MASK) |
507 | return -ENXIO; | |
dd22f551 MW |
508 | return min(avail, size); |
509 | } | |
510 | EXPORT_SYMBOL_GPL(bdev_direct_access); | |
511 | ||
2d96afc8 TK |
512 | /** |
513 | * bdev_dax_supported() - Check if the device supports dax for filesystem | |
514 | * @sb: The superblock of the device | |
515 | * @blocksize: The block size of the device | |
516 | * | |
517 | * This is a library function for filesystems to check if the block device | |
518 | * can be mounted with dax option. | |
519 | * | |
520 | * Return: negative errno if unsupported, 0 if supported. | |
521 | */ | |
522 | int bdev_dax_supported(struct super_block *sb, int blocksize) | |
523 | { | |
524 | struct blk_dax_ctl dax = { | |
525 | .sector = 0, | |
526 | .size = PAGE_SIZE, | |
527 | }; | |
528 | int err; | |
529 | ||
530 | if (blocksize != PAGE_SIZE) { | |
531 | vfs_msg(sb, KERN_ERR, "error: unsupported blocksize for dax"); | |
532 | return -EINVAL; | |
533 | } | |
534 | ||
535 | err = bdev_direct_access(sb->s_bdev, &dax); | |
536 | if (err < 0) { | |
537 | switch (err) { | |
538 | case -EOPNOTSUPP: | |
539 | vfs_msg(sb, KERN_ERR, | |
540 | "error: device does not support dax"); | |
541 | break; | |
542 | case -EINVAL: | |
543 | vfs_msg(sb, KERN_ERR, | |
544 | "error: unaligned partition for dax"); | |
545 | break; | |
546 | default: | |
547 | vfs_msg(sb, KERN_ERR, | |
548 | "error: dax access failed (%d)", err); | |
549 | } | |
550 | return err; | |
551 | } | |
552 | ||
553 | return 0; | |
554 | } | |
555 | EXPORT_SYMBOL_GPL(bdev_dax_supported); | |
556 | ||
1da177e4 LT |
557 | /* |
558 | * pseudo-fs | |
559 | */ | |
560 | ||
561 | static __cacheline_aligned_in_smp DEFINE_SPINLOCK(bdev_lock); | |
e18b890b | 562 | static struct kmem_cache * bdev_cachep __read_mostly; |
1da177e4 LT |
563 | |
564 | static struct inode *bdev_alloc_inode(struct super_block *sb) | |
565 | { | |
e94b1766 | 566 | struct bdev_inode *ei = kmem_cache_alloc(bdev_cachep, GFP_KERNEL); |
1da177e4 LT |
567 | if (!ei) |
568 | return NULL; | |
569 | return &ei->vfs_inode; | |
570 | } | |
571 | ||
fa0d7e3d | 572 | static void bdev_i_callback(struct rcu_head *head) |
1da177e4 | 573 | { |
fa0d7e3d | 574 | struct inode *inode = container_of(head, struct inode, i_rcu); |
1da177e4 LT |
575 | struct bdev_inode *bdi = BDEV_I(inode); |
576 | ||
1da177e4 LT |
577 | kmem_cache_free(bdev_cachep, bdi); |
578 | } | |
579 | ||
fa0d7e3d NP |
580 | static void bdev_destroy_inode(struct inode *inode) |
581 | { | |
582 | call_rcu(&inode->i_rcu, bdev_i_callback); | |
583 | } | |
584 | ||
51cc5068 | 585 | static void init_once(void *foo) |
1da177e4 LT |
586 | { |
587 | struct bdev_inode *ei = (struct bdev_inode *) foo; | |
588 | struct block_device *bdev = &ei->bdev; | |
589 | ||
a35afb83 CL |
590 | memset(bdev, 0, sizeof(*bdev)); |
591 | mutex_init(&bdev->bd_mutex); | |
a35afb83 CL |
592 | INIT_LIST_HEAD(&bdev->bd_inodes); |
593 | INIT_LIST_HEAD(&bdev->bd_list); | |
49731baa TH |
594 | #ifdef CONFIG_SYSFS |
595 | INIT_LIST_HEAD(&bdev->bd_holder_disks); | |
596 | #endif | |
a35afb83 | 597 | inode_init_once(&ei->vfs_inode); |
fcccf502 TS |
598 | /* Initialize mutex for freeze. */ |
599 | mutex_init(&bdev->bd_fsfreeze_mutex); | |
1da177e4 LT |
600 | } |
601 | ||
602 | static inline void __bd_forget(struct inode *inode) | |
603 | { | |
604 | list_del_init(&inode->i_devices); | |
605 | inode->i_bdev = NULL; | |
606 | inode->i_mapping = &inode->i_data; | |
607 | } | |
608 | ||
b57922d9 | 609 | static void bdev_evict_inode(struct inode *inode) |
1da177e4 LT |
610 | { |
611 | struct block_device *bdev = &BDEV_I(inode)->bdev; | |
612 | struct list_head *p; | |
91b0abe3 | 613 | truncate_inode_pages_final(&inode->i_data); |
b57922d9 | 614 | invalidate_inode_buffers(inode); /* is it needed here? */ |
dbd5768f | 615 | clear_inode(inode); |
1da177e4 LT |
616 | spin_lock(&bdev_lock); |
617 | while ( (p = bdev->bd_inodes.next) != &bdev->bd_inodes ) { | |
618 | __bd_forget(list_entry(p, struct inode, i_devices)); | |
619 | } | |
620 | list_del_init(&bdev->bd_list); | |
621 | spin_unlock(&bdev_lock); | |
622 | } | |
623 | ||
ee9b6d61 | 624 | static const struct super_operations bdev_sops = { |
1da177e4 LT |
625 | .statfs = simple_statfs, |
626 | .alloc_inode = bdev_alloc_inode, | |
627 | .destroy_inode = bdev_destroy_inode, | |
628 | .drop_inode = generic_delete_inode, | |
b57922d9 | 629 | .evict_inode = bdev_evict_inode, |
1da177e4 LT |
630 | }; |
631 | ||
51139ada AV |
632 | static struct dentry *bd_mount(struct file_system_type *fs_type, |
633 | int flags, const char *dev_name, void *data) | |
1da177e4 | 634 | { |
3684aa70 SL |
635 | struct dentry *dent; |
636 | dent = mount_pseudo(fs_type, "bdev:", &bdev_sops, NULL, BDEVFS_MAGIC); | |
637 | if (dent) | |
638 | dent->d_sb->s_iflags |= SB_I_CGROUPWB; | |
639 | return dent; | |
1da177e4 LT |
640 | } |
641 | ||
642 | static struct file_system_type bd_type = { | |
643 | .name = "bdev", | |
51139ada | 644 | .mount = bd_mount, |
1da177e4 LT |
645 | .kill_sb = kill_anon_super, |
646 | }; | |
647 | ||
a212b105 TH |
648 | struct super_block *blockdev_superblock __read_mostly; |
649 | EXPORT_SYMBOL_GPL(blockdev_superblock); | |
1da177e4 LT |
650 | |
651 | void __init bdev_cache_init(void) | |
652 | { | |
653 | int err; | |
ace8577a | 654 | static struct vfsmount *bd_mnt; |
c2acf7b9 | 655 | |
1da177e4 | 656 | bdev_cachep = kmem_cache_create("bdev_cache", sizeof(struct bdev_inode), |
fffb60f9 | 657 | 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT| |
5d097056 | 658 | SLAB_MEM_SPREAD|SLAB_ACCOUNT|SLAB_PANIC), |
20c2df83 | 659 | init_once); |
1da177e4 LT |
660 | err = register_filesystem(&bd_type); |
661 | if (err) | |
662 | panic("Cannot register bdev pseudo-fs"); | |
663 | bd_mnt = kern_mount(&bd_type); | |
1da177e4 LT |
664 | if (IS_ERR(bd_mnt)) |
665 | panic("Cannot create bdev pseudo-fs"); | |
ace8577a | 666 | blockdev_superblock = bd_mnt->mnt_sb; /* For writeback */ |
1da177e4 LT |
667 | } |
668 | ||
669 | /* | |
670 | * Most likely _very_ bad one - but then it's hardly critical for small | |
671 | * /dev and can be fixed when somebody will need really large one. | |
672 | * Keep in mind that it will be fed through icache hash function too. | |
673 | */ | |
674 | static inline unsigned long hash(dev_t dev) | |
675 | { | |
676 | return MAJOR(dev)+MINOR(dev); | |
677 | } | |
678 | ||
679 | static int bdev_test(struct inode *inode, void *data) | |
680 | { | |
681 | return BDEV_I(inode)->bdev.bd_dev == *(dev_t *)data; | |
682 | } | |
683 | ||
684 | static int bdev_set(struct inode *inode, void *data) | |
685 | { | |
686 | BDEV_I(inode)->bdev.bd_dev = *(dev_t *)data; | |
687 | return 0; | |
688 | } | |
689 | ||
690 | static LIST_HEAD(all_bdevs); | |
691 | ||
692 | struct block_device *bdget(dev_t dev) | |
693 | { | |
694 | struct block_device *bdev; | |
695 | struct inode *inode; | |
696 | ||
c2acf7b9 | 697 | inode = iget5_locked(blockdev_superblock, hash(dev), |
1da177e4 LT |
698 | bdev_test, bdev_set, &dev); |
699 | ||
700 | if (!inode) | |
701 | return NULL; | |
702 | ||
703 | bdev = &BDEV_I(inode)->bdev; | |
704 | ||
705 | if (inode->i_state & I_NEW) { | |
706 | bdev->bd_contains = NULL; | |
782b94cd | 707 | bdev->bd_super = NULL; |
1da177e4 LT |
708 | bdev->bd_inode = inode; |
709 | bdev->bd_block_size = (1 << inode->i_blkbits); | |
710 | bdev->bd_part_count = 0; | |
711 | bdev->bd_invalidated = 0; | |
712 | inode->i_mode = S_IFBLK; | |
713 | inode->i_rdev = dev; | |
714 | inode->i_bdev = bdev; | |
715 | inode->i_data.a_ops = &def_blk_aops; | |
716 | mapping_set_gfp_mask(&inode->i_data, GFP_USER); | |
1da177e4 LT |
717 | spin_lock(&bdev_lock); |
718 | list_add(&bdev->bd_list, &all_bdevs); | |
719 | spin_unlock(&bdev_lock); | |
720 | unlock_new_inode(inode); | |
721 | } | |
722 | return bdev; | |
723 | } | |
724 | ||
725 | EXPORT_SYMBOL(bdget); | |
726 | ||
dddac6a7 AJ |
727 | /** |
728 | * bdgrab -- Grab a reference to an already referenced block device | |
729 | * @bdev: Block device to grab a reference to. | |
730 | */ | |
731 | struct block_device *bdgrab(struct block_device *bdev) | |
732 | { | |
7de9c6ee | 733 | ihold(bdev->bd_inode); |
dddac6a7 AJ |
734 | return bdev; |
735 | } | |
c1681bf8 | 736 | EXPORT_SYMBOL(bdgrab); |
dddac6a7 | 737 | |
1da177e4 LT |
738 | long nr_blockdev_pages(void) |
739 | { | |
203a2935 | 740 | struct block_device *bdev; |
1da177e4 LT |
741 | long ret = 0; |
742 | spin_lock(&bdev_lock); | |
203a2935 | 743 | list_for_each_entry(bdev, &all_bdevs, bd_list) { |
1da177e4 LT |
744 | ret += bdev->bd_inode->i_mapping->nrpages; |
745 | } | |
746 | spin_unlock(&bdev_lock); | |
747 | return ret; | |
748 | } | |
749 | ||
750 | void bdput(struct block_device *bdev) | |
751 | { | |
752 | iput(bdev->bd_inode); | |
753 | } | |
754 | ||
755 | EXPORT_SYMBOL(bdput); | |
756 | ||
757 | static struct block_device *bd_acquire(struct inode *inode) | |
758 | { | |
759 | struct block_device *bdev; | |
09d967c6 | 760 | |
1da177e4 LT |
761 | spin_lock(&bdev_lock); |
762 | bdev = inode->i_bdev; | |
09d967c6 | 763 | if (bdev) { |
ed8a9d2c | 764 | bdgrab(bdev); |
1da177e4 LT |
765 | spin_unlock(&bdev_lock); |
766 | return bdev; | |
767 | } | |
768 | spin_unlock(&bdev_lock); | |
09d967c6 | 769 | |
1da177e4 LT |
770 | bdev = bdget(inode->i_rdev); |
771 | if (bdev) { | |
772 | spin_lock(&bdev_lock); | |
09d967c6 OH |
773 | if (!inode->i_bdev) { |
774 | /* | |
7de9c6ee | 775 | * We take an additional reference to bd_inode, |
09d967c6 OH |
776 | * and it's released in clear_inode() of inode. |
777 | * So, we can access it via ->i_mapping always | |
778 | * without igrab(). | |
779 | */ | |
ed8a9d2c | 780 | bdgrab(bdev); |
09d967c6 OH |
781 | inode->i_bdev = bdev; |
782 | inode->i_mapping = bdev->bd_inode->i_mapping; | |
783 | list_add(&inode->i_devices, &bdev->bd_inodes); | |
784 | } | |
1da177e4 LT |
785 | spin_unlock(&bdev_lock); |
786 | } | |
787 | return bdev; | |
788 | } | |
789 | ||
790 | /* Call when you free inode */ | |
791 | ||
792 | void bd_forget(struct inode *inode) | |
793 | { | |
09d967c6 OH |
794 | struct block_device *bdev = NULL; |
795 | ||
1da177e4 | 796 | spin_lock(&bdev_lock); |
b4ea2eaa YH |
797 | if (!sb_is_blkdev_sb(inode->i_sb)) |
798 | bdev = inode->i_bdev; | |
799 | __bd_forget(inode); | |
1da177e4 | 800 | spin_unlock(&bdev_lock); |
09d967c6 OH |
801 | |
802 | if (bdev) | |
ed8a9d2c | 803 | bdput(bdev); |
1da177e4 LT |
804 | } |
805 | ||
1a3cbbc5 TH |
806 | /** |
807 | * bd_may_claim - test whether a block device can be claimed | |
808 | * @bdev: block device of interest | |
809 | * @whole: whole block device containing @bdev, may equal @bdev | |
810 | * @holder: holder trying to claim @bdev | |
811 | * | |
25985edc | 812 | * Test whether @bdev can be claimed by @holder. |
1a3cbbc5 TH |
813 | * |
814 | * CONTEXT: | |
815 | * spin_lock(&bdev_lock). | |
816 | * | |
817 | * RETURNS: | |
818 | * %true if @bdev can be claimed, %false otherwise. | |
819 | */ | |
820 | static bool bd_may_claim(struct block_device *bdev, struct block_device *whole, | |
821 | void *holder) | |
1da177e4 | 822 | { |
1da177e4 | 823 | if (bdev->bd_holder == holder) |
1a3cbbc5 | 824 | return true; /* already a holder */ |
1da177e4 | 825 | else if (bdev->bd_holder != NULL) |
1a3cbbc5 | 826 | return false; /* held by someone else */ |
1da177e4 | 827 | else if (bdev->bd_contains == bdev) |
1a3cbbc5 | 828 | return true; /* is a whole device which isn't held */ |
1da177e4 | 829 | |
e525fd89 | 830 | else if (whole->bd_holder == bd_may_claim) |
1a3cbbc5 TH |
831 | return true; /* is a partition of a device that is being partitioned */ |
832 | else if (whole->bd_holder != NULL) | |
833 | return false; /* is a partition of a held device */ | |
1da177e4 | 834 | else |
1a3cbbc5 TH |
835 | return true; /* is a partition of an un-held device */ |
836 | } | |
837 | ||
6b4517a7 TH |
838 | /** |
839 | * bd_prepare_to_claim - prepare to claim a block device | |
840 | * @bdev: block device of interest | |
841 | * @whole: the whole device containing @bdev, may equal @bdev | |
842 | * @holder: holder trying to claim @bdev | |
843 | * | |
844 | * Prepare to claim @bdev. This function fails if @bdev is already | |
845 | * claimed by another holder and waits if another claiming is in | |
846 | * progress. This function doesn't actually claim. On successful | |
847 | * return, the caller has ownership of bd_claiming and bd_holder[s]. | |
848 | * | |
849 | * CONTEXT: | |
850 | * spin_lock(&bdev_lock). Might release bdev_lock, sleep and regrab | |
851 | * it multiple times. | |
852 | * | |
853 | * RETURNS: | |
854 | * 0 if @bdev can be claimed, -EBUSY otherwise. | |
855 | */ | |
856 | static int bd_prepare_to_claim(struct block_device *bdev, | |
857 | struct block_device *whole, void *holder) | |
858 | { | |
859 | retry: | |
860 | /* if someone else claimed, fail */ | |
861 | if (!bd_may_claim(bdev, whole, holder)) | |
862 | return -EBUSY; | |
863 | ||
e75aa858 TH |
864 | /* if claiming is already in progress, wait for it to finish */ |
865 | if (whole->bd_claiming) { | |
6b4517a7 TH |
866 | wait_queue_head_t *wq = bit_waitqueue(&whole->bd_claiming, 0); |
867 | DEFINE_WAIT(wait); | |
868 | ||
869 | prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE); | |
870 | spin_unlock(&bdev_lock); | |
871 | schedule(); | |
872 | finish_wait(wq, &wait); | |
873 | spin_lock(&bdev_lock); | |
874 | goto retry; | |
875 | } | |
876 | ||
877 | /* yay, all mine */ | |
878 | return 0; | |
879 | } | |
880 | ||
881 | /** | |
882 | * bd_start_claiming - start claiming a block device | |
883 | * @bdev: block device of interest | |
884 | * @holder: holder trying to claim @bdev | |
885 | * | |
886 | * @bdev is about to be opened exclusively. Check @bdev can be opened | |
887 | * exclusively and mark that an exclusive open is in progress. Each | |
888 | * successful call to this function must be matched with a call to | |
b0018361 NP |
889 | * either bd_finish_claiming() or bd_abort_claiming() (which do not |
890 | * fail). | |
891 | * | |
892 | * This function is used to gain exclusive access to the block device | |
893 | * without actually causing other exclusive open attempts to fail. It | |
894 | * should be used when the open sequence itself requires exclusive | |
895 | * access but may subsequently fail. | |
6b4517a7 TH |
896 | * |
897 | * CONTEXT: | |
898 | * Might sleep. | |
899 | * | |
900 | * RETURNS: | |
901 | * Pointer to the block device containing @bdev on success, ERR_PTR() | |
902 | * value on failure. | |
903 | */ | |
904 | static struct block_device *bd_start_claiming(struct block_device *bdev, | |
905 | void *holder) | |
906 | { | |
907 | struct gendisk *disk; | |
908 | struct block_device *whole; | |
909 | int partno, err; | |
910 | ||
911 | might_sleep(); | |
912 | ||
913 | /* | |
914 | * @bdev might not have been initialized properly yet, look up | |
915 | * and grab the outer block device the hard way. | |
916 | */ | |
917 | disk = get_gendisk(bdev->bd_dev, &partno); | |
918 | if (!disk) | |
919 | return ERR_PTR(-ENXIO); | |
920 | ||
d4c208b8 TH |
921 | /* |
922 | * Normally, @bdev should equal what's returned from bdget_disk() | |
923 | * if partno is 0; however, some drivers (floppy) use multiple | |
924 | * bdev's for the same physical device and @bdev may be one of the | |
925 | * aliases. Keep @bdev if partno is 0. This means claimer | |
926 | * tracking is broken for those devices but it has always been that | |
927 | * way. | |
928 | */ | |
929 | if (partno) | |
930 | whole = bdget_disk(disk, 0); | |
931 | else | |
932 | whole = bdgrab(bdev); | |
933 | ||
cf342570 | 934 | module_put(disk->fops->owner); |
6b4517a7 TH |
935 | put_disk(disk); |
936 | if (!whole) | |
937 | return ERR_PTR(-ENOMEM); | |
938 | ||
939 | /* prepare to claim, if successful, mark claiming in progress */ | |
940 | spin_lock(&bdev_lock); | |
941 | ||
942 | err = bd_prepare_to_claim(bdev, whole, holder); | |
943 | if (err == 0) { | |
944 | whole->bd_claiming = holder; | |
945 | spin_unlock(&bdev_lock); | |
946 | return whole; | |
947 | } else { | |
948 | spin_unlock(&bdev_lock); | |
949 | bdput(whole); | |
950 | return ERR_PTR(err); | |
951 | } | |
952 | } | |
953 | ||
641dc636 | 954 | #ifdef CONFIG_SYSFS |
49731baa TH |
955 | struct bd_holder_disk { |
956 | struct list_head list; | |
957 | struct gendisk *disk; | |
958 | int refcnt; | |
959 | }; | |
960 | ||
961 | static struct bd_holder_disk *bd_find_holder_disk(struct block_device *bdev, | |
962 | struct gendisk *disk) | |
963 | { | |
964 | struct bd_holder_disk *holder; | |
965 | ||
966 | list_for_each_entry(holder, &bdev->bd_holder_disks, list) | |
967 | if (holder->disk == disk) | |
968 | return holder; | |
969 | return NULL; | |
970 | } | |
971 | ||
4d7dd8fd | 972 | static int add_symlink(struct kobject *from, struct kobject *to) |
641dc636 | 973 | { |
4d7dd8fd | 974 | return sysfs_create_link(from, to, kobject_name(to)); |
641dc636 JN |
975 | } |
976 | ||
977 | static void del_symlink(struct kobject *from, struct kobject *to) | |
978 | { | |
641dc636 JN |
979 | sysfs_remove_link(from, kobject_name(to)); |
980 | } | |
981 | ||
df6c0cd9 | 982 | /** |
e09b457b TH |
983 | * bd_link_disk_holder - create symlinks between holding disk and slave bdev |
984 | * @bdev: the claimed slave bdev | |
985 | * @disk: the holding disk | |
df6c0cd9 | 986 | * |
49731baa TH |
987 | * DON'T USE THIS UNLESS YOU'RE ALREADY USING IT. |
988 | * | |
e09b457b | 989 | * This functions creates the following sysfs symlinks. |
641dc636 | 990 | * |
e09b457b TH |
991 | * - from "slaves" directory of the holder @disk to the claimed @bdev |
992 | * - from "holders" directory of the @bdev to the holder @disk | |
641dc636 | 993 | * |
e09b457b TH |
994 | * For example, if /dev/dm-0 maps to /dev/sda and disk for dm-0 is |
995 | * passed to bd_link_disk_holder(), then: | |
641dc636 | 996 | * |
e09b457b TH |
997 | * /sys/block/dm-0/slaves/sda --> /sys/block/sda |
998 | * /sys/block/sda/holders/dm-0 --> /sys/block/dm-0 | |
641dc636 | 999 | * |
e09b457b TH |
1000 | * The caller must have claimed @bdev before calling this function and |
1001 | * ensure that both @bdev and @disk are valid during the creation and | |
1002 | * lifetime of these symlinks. | |
641dc636 | 1003 | * |
e09b457b TH |
1004 | * CONTEXT: |
1005 | * Might sleep. | |
641dc636 | 1006 | * |
e09b457b TH |
1007 | * RETURNS: |
1008 | * 0 on success, -errno on failure. | |
641dc636 | 1009 | */ |
e09b457b | 1010 | int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk) |
641dc636 | 1011 | { |
49731baa | 1012 | struct bd_holder_disk *holder; |
e09b457b | 1013 | int ret = 0; |
641dc636 | 1014 | |
2e7b651d | 1015 | mutex_lock(&bdev->bd_mutex); |
df6c0cd9 | 1016 | |
49731baa | 1017 | WARN_ON_ONCE(!bdev->bd_holder); |
4e91672c | 1018 | |
e09b457b TH |
1019 | /* FIXME: remove the following once add_disk() handles errors */ |
1020 | if (WARN_ON(!disk->slave_dir || !bdev->bd_part->holder_dir)) | |
1021 | goto out_unlock; | |
4e91672c | 1022 | |
49731baa TH |
1023 | holder = bd_find_holder_disk(bdev, disk); |
1024 | if (holder) { | |
1025 | holder->refcnt++; | |
e09b457b | 1026 | goto out_unlock; |
49731baa | 1027 | } |
641dc636 | 1028 | |
49731baa TH |
1029 | holder = kzalloc(sizeof(*holder), GFP_KERNEL); |
1030 | if (!holder) { | |
1031 | ret = -ENOMEM; | |
e09b457b TH |
1032 | goto out_unlock; |
1033 | } | |
641dc636 | 1034 | |
49731baa TH |
1035 | INIT_LIST_HEAD(&holder->list); |
1036 | holder->disk = disk; | |
1037 | holder->refcnt = 1; | |
1038 | ||
1039 | ret = add_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj); | |
1040 | if (ret) | |
1041 | goto out_free; | |
1042 | ||
1043 | ret = add_symlink(bdev->bd_part->holder_dir, &disk_to_dev(disk)->kobj); | |
1044 | if (ret) | |
1045 | goto out_del; | |
e7407d16 TH |
1046 | /* |
1047 | * bdev could be deleted beneath us which would implicitly destroy | |
1048 | * the holder directory. Hold on to it. | |
1049 | */ | |
1050 | kobject_get(bdev->bd_part->holder_dir); | |
49731baa TH |
1051 | |
1052 | list_add(&holder->list, &bdev->bd_holder_disks); | |
1053 | goto out_unlock; | |
1054 | ||
1055 | out_del: | |
1056 | del_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj); | |
1057 | out_free: | |
1058 | kfree(holder); | |
e09b457b | 1059 | out_unlock: |
b4cf1b72 | 1060 | mutex_unlock(&bdev->bd_mutex); |
e09b457b | 1061 | return ret; |
641dc636 | 1062 | } |
e09b457b | 1063 | EXPORT_SYMBOL_GPL(bd_link_disk_holder); |
641dc636 | 1064 | |
49731baa TH |
1065 | /** |
1066 | * bd_unlink_disk_holder - destroy symlinks created by bd_link_disk_holder() | |
1067 | * @bdev: the calimed slave bdev | |
1068 | * @disk: the holding disk | |
1069 | * | |
1070 | * DON'T USE THIS UNLESS YOU'RE ALREADY USING IT. | |
1071 | * | |
1072 | * CONTEXT: | |
1073 | * Might sleep. | |
1074 | */ | |
1075 | void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk) | |
641dc636 | 1076 | { |
49731baa | 1077 | struct bd_holder_disk *holder; |
641dc636 | 1078 | |
49731baa | 1079 | mutex_lock(&bdev->bd_mutex); |
641dc636 | 1080 | |
49731baa TH |
1081 | holder = bd_find_holder_disk(bdev, disk); |
1082 | ||
1083 | if (!WARN_ON_ONCE(holder == NULL) && !--holder->refcnt) { | |
1084 | del_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj); | |
1085 | del_symlink(bdev->bd_part->holder_dir, | |
1086 | &disk_to_dev(disk)->kobj); | |
e7407d16 | 1087 | kobject_put(bdev->bd_part->holder_dir); |
49731baa TH |
1088 | list_del_init(&holder->list); |
1089 | kfree(holder); | |
1090 | } | |
1091 | ||
1092 | mutex_unlock(&bdev->bd_mutex); | |
1da177e4 | 1093 | } |
49731baa | 1094 | EXPORT_SYMBOL_GPL(bd_unlink_disk_holder); |
641dc636 | 1095 | #endif |
1da177e4 | 1096 | |
56ade44b AP |
1097 | /** |
1098 | * flush_disk - invalidates all buffer-cache entries on a disk | |
1099 | * | |
1100 | * @bdev: struct block device to be flushed | |
e6eb5ce1 | 1101 | * @kill_dirty: flag to guide handling of dirty inodes |
56ade44b AP |
1102 | * |
1103 | * Invalidates all buffer-cache entries on a disk. It should be called | |
1104 | * when a disk has been changed -- either by a media change or online | |
1105 | * resize. | |
1106 | */ | |
93b270f7 | 1107 | static void flush_disk(struct block_device *bdev, bool kill_dirty) |
56ade44b | 1108 | { |
93b270f7 | 1109 | if (__invalidate_device(bdev, kill_dirty)) { |
56ade44b | 1110 | printk(KERN_WARNING "VFS: busy inodes on changed media or " |
424081f3 DM |
1111 | "resized disk %s\n", |
1112 | bdev->bd_disk ? bdev->bd_disk->disk_name : ""); | |
56ade44b AP |
1113 | } |
1114 | ||
1115 | if (!bdev->bd_disk) | |
1116 | return; | |
d27769ec | 1117 | if (disk_part_scan_enabled(bdev->bd_disk)) |
56ade44b AP |
1118 | bdev->bd_invalidated = 1; |
1119 | } | |
1120 | ||
c3279d14 | 1121 | /** |
57d1b536 | 1122 | * check_disk_size_change - checks for disk size change and adjusts bdev size. |
c3279d14 AP |
1123 | * @disk: struct gendisk to check |
1124 | * @bdev: struct bdev to adjust. | |
1125 | * | |
1126 | * This routine checks to see if the bdev size does not match the disk size | |
1127 | * and adjusts it if it differs. | |
1128 | */ | |
1129 | void check_disk_size_change(struct gendisk *disk, struct block_device *bdev) | |
1130 | { | |
1131 | loff_t disk_size, bdev_size; | |
1132 | ||
1133 | disk_size = (loff_t)get_capacity(disk) << 9; | |
1134 | bdev_size = i_size_read(bdev->bd_inode); | |
1135 | if (disk_size != bdev_size) { | |
c3279d14 AP |
1136 | printk(KERN_INFO |
1137 | "%s: detected capacity change from %lld to %lld\n", | |
424081f3 | 1138 | disk->disk_name, bdev_size, disk_size); |
c3279d14 | 1139 | i_size_write(bdev->bd_inode, disk_size); |
93b270f7 | 1140 | flush_disk(bdev, false); |
c3279d14 AP |
1141 | } |
1142 | } | |
1143 | EXPORT_SYMBOL(check_disk_size_change); | |
1144 | ||
0c002c2f | 1145 | /** |
57d1b536 | 1146 | * revalidate_disk - wrapper for lower-level driver's revalidate_disk call-back |
0c002c2f AP |
1147 | * @disk: struct gendisk to be revalidated |
1148 | * | |
1149 | * This routine is a wrapper for lower-level driver's revalidate_disk | |
1150 | * call-backs. It is used to do common pre and post operations needed | |
1151 | * for all revalidate_disk operations. | |
1152 | */ | |
1153 | int revalidate_disk(struct gendisk *disk) | |
1154 | { | |
c3279d14 | 1155 | struct block_device *bdev; |
0c002c2f AP |
1156 | int ret = 0; |
1157 | ||
1158 | if (disk->fops->revalidate_disk) | |
1159 | ret = disk->fops->revalidate_disk(disk); | |
25520d55 | 1160 | blk_integrity_revalidate(disk); |
c3279d14 AP |
1161 | bdev = bdget_disk(disk, 0); |
1162 | if (!bdev) | |
1163 | return ret; | |
1164 | ||
1165 | mutex_lock(&bdev->bd_mutex); | |
1166 | check_disk_size_change(disk, bdev); | |
7630b661 | 1167 | bdev->bd_invalidated = 0; |
c3279d14 AP |
1168 | mutex_unlock(&bdev->bd_mutex); |
1169 | bdput(bdev); | |
0c002c2f AP |
1170 | return ret; |
1171 | } | |
1172 | EXPORT_SYMBOL(revalidate_disk); | |
1173 | ||
1da177e4 LT |
1174 | /* |
1175 | * This routine checks whether a removable media has been changed, | |
1176 | * and invalidates all buffer-cache-entries in that case. This | |
1177 | * is a relatively slow routine, so we have to try to minimize using | |
1178 | * it. Thus it is called only upon a 'mount' or 'open'. This | |
1179 | * is the best way of combining speed and utility, I think. | |
1180 | * People changing diskettes in the middle of an operation deserve | |
1181 | * to lose :-) | |
1182 | */ | |
1183 | int check_disk_change(struct block_device *bdev) | |
1184 | { | |
1185 | struct gendisk *disk = bdev->bd_disk; | |
83d5cde4 | 1186 | const struct block_device_operations *bdops = disk->fops; |
77ea887e | 1187 | unsigned int events; |
1da177e4 | 1188 | |
77ea887e TH |
1189 | events = disk_clear_events(disk, DISK_EVENT_MEDIA_CHANGE | |
1190 | DISK_EVENT_EJECT_REQUEST); | |
1191 | if (!(events & DISK_EVENT_MEDIA_CHANGE)) | |
1da177e4 LT |
1192 | return 0; |
1193 | ||
93b270f7 | 1194 | flush_disk(bdev, true); |
1da177e4 LT |
1195 | if (bdops->revalidate_disk) |
1196 | bdops->revalidate_disk(bdev->bd_disk); | |
1da177e4 LT |
1197 | return 1; |
1198 | } | |
1199 | ||
1200 | EXPORT_SYMBOL(check_disk_change); | |
1201 | ||
1202 | void bd_set_size(struct block_device *bdev, loff_t size) | |
1203 | { | |
e1defc4f | 1204 | unsigned bsize = bdev_logical_block_size(bdev); |
1da177e4 | 1205 | |
5955102c | 1206 | inode_lock(bdev->bd_inode); |
d646a02a | 1207 | i_size_write(bdev->bd_inode, size); |
5955102c | 1208 | inode_unlock(bdev->bd_inode); |
09cbfeaf | 1209 | while (bsize < PAGE_SIZE) { |
1da177e4 LT |
1210 | if (size & bsize) |
1211 | break; | |
1212 | bsize <<= 1; | |
1213 | } | |
1214 | bdev->bd_block_size = bsize; | |
1215 | bdev->bd_inode->i_blkbits = blksize_bits(bsize); | |
1216 | } | |
1217 | EXPORT_SYMBOL(bd_set_size); | |
1218 | ||
4385bab1 | 1219 | static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part); |
37be4124 | 1220 | |
6d740cd5 PZ |
1221 | /* |
1222 | * bd_mutex locking: | |
1223 | * | |
1224 | * mutex_lock(part->bd_mutex) | |
1225 | * mutex_lock_nested(whole->bd_mutex, 1) | |
1226 | */ | |
1227 | ||
572c4892 | 1228 | static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part) |
1da177e4 | 1229 | { |
1da177e4 | 1230 | struct gendisk *disk; |
523e1d39 | 1231 | struct module *owner; |
7db9cfd3 | 1232 | int ret; |
cf771cb5 | 1233 | int partno; |
fe6e9c1f AV |
1234 | int perm = 0; |
1235 | ||
572c4892 | 1236 | if (mode & FMODE_READ) |
fe6e9c1f | 1237 | perm |= MAY_READ; |
572c4892 | 1238 | if (mode & FMODE_WRITE) |
fe6e9c1f AV |
1239 | perm |= MAY_WRITE; |
1240 | /* | |
1241 | * hooks: /n/, see "layering violations". | |
1242 | */ | |
b7300b78 CW |
1243 | if (!for_part) { |
1244 | ret = devcgroup_inode_permission(bdev->bd_inode, perm); | |
1245 | if (ret != 0) { | |
1246 | bdput(bdev); | |
1247 | return ret; | |
1248 | } | |
82666020 | 1249 | } |
7db9cfd3 | 1250 | |
d3374825 | 1251 | restart: |
0762b8bd | 1252 | |
89f97496 | 1253 | ret = -ENXIO; |
cf771cb5 | 1254 | disk = get_gendisk(bdev->bd_dev, &partno); |
0762b8bd | 1255 | if (!disk) |
6e9624b8 | 1256 | goto out; |
523e1d39 | 1257 | owner = disk->fops->owner; |
1da177e4 | 1258 | |
69e02c59 | 1259 | disk_block_events(disk); |
6796bf54 | 1260 | mutex_lock_nested(&bdev->bd_mutex, for_part); |
1da177e4 LT |
1261 | if (!bdev->bd_openers) { |
1262 | bdev->bd_disk = disk; | |
87192a2a | 1263 | bdev->bd_queue = disk->queue; |
1da177e4 | 1264 | bdev->bd_contains = bdev; |
03cdadb0 DW |
1265 | if (IS_ENABLED(CONFIG_BLK_DEV_DAX) && disk->fops->direct_access) |
1266 | bdev->bd_inode->i_flags = S_DAX; | |
1267 | else | |
1268 | bdev->bd_inode->i_flags = 0; | |
1269 | ||
cf771cb5 | 1270 | if (!partno) { |
89f97496 TH |
1271 | ret = -ENXIO; |
1272 | bdev->bd_part = disk_get_part(disk, partno); | |
1273 | if (!bdev->bd_part) | |
1274 | goto out_clear; | |
1275 | ||
1196f8b8 | 1276 | ret = 0; |
1da177e4 | 1277 | if (disk->fops->open) { |
572c4892 | 1278 | ret = disk->fops->open(bdev, mode); |
d3374825 N |
1279 | if (ret == -ERESTARTSYS) { |
1280 | /* Lost a race with 'disk' being | |
1281 | * deleted, try again. | |
1282 | * See md.c | |
1283 | */ | |
1284 | disk_put_part(bdev->bd_part); | |
1285 | bdev->bd_part = NULL; | |
d3374825 | 1286 | bdev->bd_disk = NULL; |
87192a2a | 1287 | bdev->bd_queue = NULL; |
d3374825 | 1288 | mutex_unlock(&bdev->bd_mutex); |
69e02c59 | 1289 | disk_unblock_events(disk); |
69e02c59 | 1290 | put_disk(disk); |
523e1d39 | 1291 | module_put(owner); |
d3374825 N |
1292 | goto restart; |
1293 | } | |
1da177e4 | 1294 | } |
7e69723f | 1295 | |
5a023cdb | 1296 | if (!ret) { |
7e69723f | 1297 | bd_set_size(bdev,(loff_t)get_capacity(disk)<<9); |
5a023cdb DW |
1298 | if (!blkdev_dax_capable(bdev)) |
1299 | bdev->bd_inode->i_flags &= ~S_DAX; | |
1300 | } | |
7e69723f | 1301 | |
1196f8b8 TH |
1302 | /* |
1303 | * If the device is invalidated, rescan partition | |
1304 | * if open succeeded or failed with -ENOMEDIUM. | |
1305 | * The latter is necessary to prevent ghost | |
1306 | * partitions on a removed medium. | |
1307 | */ | |
fe316bf2 JN |
1308 | if (bdev->bd_invalidated) { |
1309 | if (!ret) | |
1310 | rescan_partitions(disk, bdev); | |
1311 | else if (ret == -ENOMEDIUM) | |
1312 | invalidate_partitions(disk, bdev); | |
1313 | } | |
5a023cdb | 1314 | |
1196f8b8 TH |
1315 | if (ret) |
1316 | goto out_clear; | |
1da177e4 | 1317 | } else { |
1da177e4 LT |
1318 | struct block_device *whole; |
1319 | whole = bdget_disk(disk, 0); | |
1320 | ret = -ENOMEM; | |
1321 | if (!whole) | |
0762b8bd | 1322 | goto out_clear; |
37be4124 | 1323 | BUG_ON(for_part); |
572c4892 | 1324 | ret = __blkdev_get(whole, mode, 1); |
1da177e4 | 1325 | if (ret) |
0762b8bd | 1326 | goto out_clear; |
1da177e4 | 1327 | bdev->bd_contains = whole; |
89f97496 | 1328 | bdev->bd_part = disk_get_part(disk, partno); |
e71bf0d0 | 1329 | if (!(disk->flags & GENHD_FL_UP) || |
89f97496 | 1330 | !bdev->bd_part || !bdev->bd_part->nr_sects) { |
1da177e4 | 1331 | ret = -ENXIO; |
0762b8bd | 1332 | goto out_clear; |
1da177e4 | 1333 | } |
89f97496 | 1334 | bd_set_size(bdev, (loff_t)bdev->bd_part->nr_sects << 9); |
5a023cdb | 1335 | if (!blkdev_dax_capable(bdev)) |
f0b2e563 | 1336 | bdev->bd_inode->i_flags &= ~S_DAX; |
1da177e4 LT |
1337 | } |
1338 | } else { | |
1da177e4 | 1339 | if (bdev->bd_contains == bdev) { |
1196f8b8 TH |
1340 | ret = 0; |
1341 | if (bdev->bd_disk->fops->open) | |
572c4892 | 1342 | ret = bdev->bd_disk->fops->open(bdev, mode); |
1196f8b8 | 1343 | /* the same as first opener case, read comment there */ |
fe316bf2 JN |
1344 | if (bdev->bd_invalidated) { |
1345 | if (!ret) | |
1346 | rescan_partitions(bdev->bd_disk, bdev); | |
1347 | else if (ret == -ENOMEDIUM) | |
1348 | invalidate_partitions(bdev->bd_disk, bdev); | |
1349 | } | |
1196f8b8 TH |
1350 | if (ret) |
1351 | goto out_unlock_bdev; | |
1da177e4 | 1352 | } |
69e02c59 | 1353 | /* only one opener holds refs to the module and disk */ |
69e02c59 | 1354 | put_disk(disk); |
523e1d39 | 1355 | module_put(owner); |
1da177e4 LT |
1356 | } |
1357 | bdev->bd_openers++; | |
37be4124 N |
1358 | if (for_part) |
1359 | bdev->bd_part_count++; | |
c039e313 | 1360 | mutex_unlock(&bdev->bd_mutex); |
69e02c59 | 1361 | disk_unblock_events(disk); |
1da177e4 LT |
1362 | return 0; |
1363 | ||
0762b8bd | 1364 | out_clear: |
89f97496 | 1365 | disk_put_part(bdev->bd_part); |
1da177e4 | 1366 | bdev->bd_disk = NULL; |
0762b8bd | 1367 | bdev->bd_part = NULL; |
87192a2a | 1368 | bdev->bd_queue = NULL; |
1da177e4 | 1369 | if (bdev != bdev->bd_contains) |
572c4892 | 1370 | __blkdev_put(bdev->bd_contains, mode, 1); |
1da177e4 | 1371 | bdev->bd_contains = NULL; |
0762b8bd | 1372 | out_unlock_bdev: |
c039e313 | 1373 | mutex_unlock(&bdev->bd_mutex); |
69e02c59 | 1374 | disk_unblock_events(disk); |
0762b8bd | 1375 | put_disk(disk); |
523e1d39 | 1376 | module_put(owner); |
4345caba | 1377 | out: |
0762b8bd TH |
1378 | bdput(bdev); |
1379 | ||
1da177e4 LT |
1380 | return ret; |
1381 | } | |
1382 | ||
d4d77629 TH |
1383 | /** |
1384 | * blkdev_get - open a block device | |
1385 | * @bdev: block_device to open | |
1386 | * @mode: FMODE_* mask | |
1387 | * @holder: exclusive holder identifier | |
1388 | * | |
1389 | * Open @bdev with @mode. If @mode includes %FMODE_EXCL, @bdev is | |
1390 | * open with exclusive access. Specifying %FMODE_EXCL with %NULL | |
1391 | * @holder is invalid. Exclusive opens may nest for the same @holder. | |
1392 | * | |
1393 | * On success, the reference count of @bdev is unchanged. On failure, | |
1394 | * @bdev is put. | |
1395 | * | |
1396 | * CONTEXT: | |
1397 | * Might sleep. | |
1398 | * | |
1399 | * RETURNS: | |
1400 | * 0 on success, -errno on failure. | |
1401 | */ | |
e525fd89 | 1402 | int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder) |
1da177e4 | 1403 | { |
e525fd89 TH |
1404 | struct block_device *whole = NULL; |
1405 | int res; | |
1406 | ||
1407 | WARN_ON_ONCE((mode & FMODE_EXCL) && !holder); | |
1408 | ||
1409 | if ((mode & FMODE_EXCL) && holder) { | |
1410 | whole = bd_start_claiming(bdev, holder); | |
1411 | if (IS_ERR(whole)) { | |
1412 | bdput(bdev); | |
1413 | return PTR_ERR(whole); | |
1414 | } | |
1415 | } | |
1416 | ||
1417 | res = __blkdev_get(bdev, mode, 0); | |
1418 | ||
1419 | if (whole) { | |
d4dc210f TH |
1420 | struct gendisk *disk = whole->bd_disk; |
1421 | ||
6a027eff | 1422 | /* finish claiming */ |
77ea887e | 1423 | mutex_lock(&bdev->bd_mutex); |
6a027eff TH |
1424 | spin_lock(&bdev_lock); |
1425 | ||
77ea887e | 1426 | if (!res) { |
6a027eff TH |
1427 | BUG_ON(!bd_may_claim(bdev, whole, holder)); |
1428 | /* | |
1429 | * Note that for a whole device bd_holders | |
1430 | * will be incremented twice, and bd_holder | |
1431 | * will be set to bd_may_claim before being | |
1432 | * set to holder | |
1433 | */ | |
1434 | whole->bd_holders++; | |
1435 | whole->bd_holder = bd_may_claim; | |
1436 | bdev->bd_holders++; | |
1437 | bdev->bd_holder = holder; | |
1438 | } | |
1439 | ||
1440 | /* tell others that we're done */ | |
1441 | BUG_ON(whole->bd_claiming != holder); | |
1442 | whole->bd_claiming = NULL; | |
1443 | wake_up_bit(&whole->bd_claiming, 0); | |
1444 | ||
1445 | spin_unlock(&bdev_lock); | |
77ea887e TH |
1446 | |
1447 | /* | |
d4dc210f TH |
1448 | * Block event polling for write claims if requested. Any |
1449 | * write holder makes the write_holder state stick until | |
1450 | * all are released. This is good enough and tracking | |
1451 | * individual writeable reference is too fragile given the | |
1452 | * way @mode is used in blkdev_get/put(). | |
77ea887e | 1453 | */ |
4c49ff3f TH |
1454 | if (!res && (mode & FMODE_WRITE) && !bdev->bd_write_holder && |
1455 | (disk->flags & GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE)) { | |
77ea887e | 1456 | bdev->bd_write_holder = true; |
d4dc210f | 1457 | disk_block_events(disk); |
77ea887e TH |
1458 | } |
1459 | ||
1460 | mutex_unlock(&bdev->bd_mutex); | |
6a027eff | 1461 | bdput(whole); |
e525fd89 TH |
1462 | } |
1463 | ||
1464 | return res; | |
37be4124 | 1465 | } |
1da177e4 LT |
1466 | EXPORT_SYMBOL(blkdev_get); |
1467 | ||
d4d77629 TH |
1468 | /** |
1469 | * blkdev_get_by_path - open a block device by name | |
1470 | * @path: path to the block device to open | |
1471 | * @mode: FMODE_* mask | |
1472 | * @holder: exclusive holder identifier | |
1473 | * | |
1474 | * Open the blockdevice described by the device file at @path. @mode | |
1475 | * and @holder are identical to blkdev_get(). | |
1476 | * | |
1477 | * On success, the returned block_device has reference count of one. | |
1478 | * | |
1479 | * CONTEXT: | |
1480 | * Might sleep. | |
1481 | * | |
1482 | * RETURNS: | |
1483 | * Pointer to block_device on success, ERR_PTR(-errno) on failure. | |
1484 | */ | |
1485 | struct block_device *blkdev_get_by_path(const char *path, fmode_t mode, | |
1486 | void *holder) | |
1487 | { | |
1488 | struct block_device *bdev; | |
1489 | int err; | |
1490 | ||
1491 | bdev = lookup_bdev(path); | |
1492 | if (IS_ERR(bdev)) | |
1493 | return bdev; | |
1494 | ||
1495 | err = blkdev_get(bdev, mode, holder); | |
1496 | if (err) | |
1497 | return ERR_PTR(err); | |
1498 | ||
e51900f7 CE |
1499 | if ((mode & FMODE_WRITE) && bdev_read_only(bdev)) { |
1500 | blkdev_put(bdev, mode); | |
1501 | return ERR_PTR(-EACCES); | |
1502 | } | |
1503 | ||
d4d77629 TH |
1504 | return bdev; |
1505 | } | |
1506 | EXPORT_SYMBOL(blkdev_get_by_path); | |
1507 | ||
1508 | /** | |
1509 | * blkdev_get_by_dev - open a block device by device number | |
1510 | * @dev: device number of block device to open | |
1511 | * @mode: FMODE_* mask | |
1512 | * @holder: exclusive holder identifier | |
1513 | * | |
1514 | * Open the blockdevice described by device number @dev. @mode and | |
1515 | * @holder are identical to blkdev_get(). | |
1516 | * | |
1517 | * Use it ONLY if you really do not have anything better - i.e. when | |
1518 | * you are behind a truly sucky interface and all you are given is a | |
1519 | * device number. _Never_ to be used for internal purposes. If you | |
1520 | * ever need it - reconsider your API. | |
1521 | * | |
1522 | * On success, the returned block_device has reference count of one. | |
1523 | * | |
1524 | * CONTEXT: | |
1525 | * Might sleep. | |
1526 | * | |
1527 | * RETURNS: | |
1528 | * Pointer to block_device on success, ERR_PTR(-errno) on failure. | |
1529 | */ | |
1530 | struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder) | |
1531 | { | |
1532 | struct block_device *bdev; | |
1533 | int err; | |
1534 | ||
1535 | bdev = bdget(dev); | |
1536 | if (!bdev) | |
1537 | return ERR_PTR(-ENOMEM); | |
1538 | ||
1539 | err = blkdev_get(bdev, mode, holder); | |
1540 | if (err) | |
1541 | return ERR_PTR(err); | |
1542 | ||
1543 | return bdev; | |
1544 | } | |
1545 | EXPORT_SYMBOL(blkdev_get_by_dev); | |
1546 | ||
1da177e4 LT |
1547 | static int blkdev_open(struct inode * inode, struct file * filp) |
1548 | { | |
1549 | struct block_device *bdev; | |
1da177e4 LT |
1550 | |
1551 | /* | |
1552 | * Preserve backwards compatibility and allow large file access | |
1553 | * even if userspace doesn't ask for it explicitly. Some mkfs | |
1554 | * binary needs it. We might want to drop this workaround | |
1555 | * during an unstable branch. | |
1556 | */ | |
1557 | filp->f_flags |= O_LARGEFILE; | |
1558 | ||
572c4892 AV |
1559 | if (filp->f_flags & O_NDELAY) |
1560 | filp->f_mode |= FMODE_NDELAY; | |
1561 | if (filp->f_flags & O_EXCL) | |
1562 | filp->f_mode |= FMODE_EXCL; | |
1563 | if ((filp->f_flags & O_ACCMODE) == 3) | |
1564 | filp->f_mode |= FMODE_WRITE_IOCTL; | |
1565 | ||
1da177e4 | 1566 | bdev = bd_acquire(inode); |
6a2aae06 PE |
1567 | if (bdev == NULL) |
1568 | return -ENOMEM; | |
1da177e4 | 1569 | |
572c4892 AV |
1570 | filp->f_mapping = bdev->bd_inode->i_mapping; |
1571 | ||
e525fd89 | 1572 | return blkdev_get(bdev, filp->f_mode, filp); |
1da177e4 LT |
1573 | } |
1574 | ||
4385bab1 | 1575 | static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part) |
2e7b651d | 1576 | { |
2e7b651d | 1577 | struct gendisk *disk = bdev->bd_disk; |
37be4124 | 1578 | struct block_device *victim = NULL; |
2e7b651d | 1579 | |
6796bf54 | 1580 | mutex_lock_nested(&bdev->bd_mutex, for_part); |
37be4124 N |
1581 | if (for_part) |
1582 | bdev->bd_part_count--; | |
1583 | ||
2e7b651d | 1584 | if (!--bdev->bd_openers) { |
6a027eff | 1585 | WARN_ON_ONCE(bdev->bd_holders); |
2e7b651d PZ |
1586 | sync_blockdev(bdev); |
1587 | kill_bdev(bdev); | |
43d1c0eb ID |
1588 | |
1589 | bdev_write_inode(bdev); | |
564f00f6 | 1590 | /* |
43d1c0eb ID |
1591 | * Detaching bdev inode from its wb in __destroy_inode() |
1592 | * is too late: the queue which embeds its bdi (along with | |
1593 | * root wb) can be gone as soon as we put_disk() below. | |
94007751 | 1594 | */ |
43d1c0eb | 1595 | inode_detach_wb(bdev->bd_inode); |
2e7b651d PZ |
1596 | } |
1597 | if (bdev->bd_contains == bdev) { | |
1598 | if (disk->fops->release) | |
db2a144b | 1599 | disk->fops->release(disk, mode); |
2e7b651d PZ |
1600 | } |
1601 | if (!bdev->bd_openers) { | |
1602 | struct module *owner = disk->fops->owner; | |
1603 | ||
0762b8bd TH |
1604 | disk_put_part(bdev->bd_part); |
1605 | bdev->bd_part = NULL; | |
2e7b651d | 1606 | bdev->bd_disk = NULL; |
37be4124 N |
1607 | if (bdev != bdev->bd_contains) |
1608 | victim = bdev->bd_contains; | |
2e7b651d | 1609 | bdev->bd_contains = NULL; |
523e1d39 TH |
1610 | |
1611 | put_disk(disk); | |
1612 | module_put(owner); | |
2e7b651d | 1613 | } |
2e7b651d PZ |
1614 | mutex_unlock(&bdev->bd_mutex); |
1615 | bdput(bdev); | |
37be4124 | 1616 | if (victim) |
9a1c3542 | 1617 | __blkdev_put(victim, mode, 1); |
2e7b651d PZ |
1618 | } |
1619 | ||
4385bab1 | 1620 | void blkdev_put(struct block_device *bdev, fmode_t mode) |
37be4124 | 1621 | { |
85ef06d1 TH |
1622 | mutex_lock(&bdev->bd_mutex); |
1623 | ||
e525fd89 | 1624 | if (mode & FMODE_EXCL) { |
6a027eff TH |
1625 | bool bdev_free; |
1626 | ||
1627 | /* | |
1628 | * Release a claim on the device. The holder fields | |
1629 | * are protected with bdev_lock. bd_mutex is to | |
1630 | * synchronize disk_holder unlinking. | |
1631 | */ | |
6a027eff TH |
1632 | spin_lock(&bdev_lock); |
1633 | ||
1634 | WARN_ON_ONCE(--bdev->bd_holders < 0); | |
1635 | WARN_ON_ONCE(--bdev->bd_contains->bd_holders < 0); | |
1636 | ||
1637 | /* bd_contains might point to self, check in a separate step */ | |
1638 | if ((bdev_free = !bdev->bd_holders)) | |
1639 | bdev->bd_holder = NULL; | |
1640 | if (!bdev->bd_contains->bd_holders) | |
1641 | bdev->bd_contains->bd_holder = NULL; | |
1642 | ||
1643 | spin_unlock(&bdev_lock); | |
1644 | ||
77ea887e TH |
1645 | /* |
1646 | * If this was the last claim, remove holder link and | |
1647 | * unblock evpoll if it was a write holder. | |
1648 | */ | |
85ef06d1 TH |
1649 | if (bdev_free && bdev->bd_write_holder) { |
1650 | disk_unblock_events(bdev->bd_disk); | |
1651 | bdev->bd_write_holder = false; | |
77ea887e | 1652 | } |
6936217c | 1653 | } |
77ea887e | 1654 | |
85ef06d1 TH |
1655 | /* |
1656 | * Trigger event checking and tell drivers to flush MEDIA_CHANGE | |
1657 | * event. This is to ensure detection of media removal commanded | |
1658 | * from userland - e.g. eject(1). | |
1659 | */ | |
1660 | disk_flush_events(bdev->bd_disk, DISK_EVENT_MEDIA_CHANGE); | |
1661 | ||
1662 | mutex_unlock(&bdev->bd_mutex); | |
1663 | ||
4385bab1 | 1664 | __blkdev_put(bdev, mode, 0); |
37be4124 | 1665 | } |
2e7b651d PZ |
1666 | EXPORT_SYMBOL(blkdev_put); |
1667 | ||
1da177e4 LT |
1668 | static int blkdev_close(struct inode * inode, struct file * filp) |
1669 | { | |
4ebb16ca | 1670 | struct block_device *bdev = I_BDEV(bdev_file_inode(filp)); |
4385bab1 AV |
1671 | blkdev_put(bdev, filp->f_mode); |
1672 | return 0; | |
1da177e4 LT |
1673 | } |
1674 | ||
bb93e3a5 | 1675 | static long block_ioctl(struct file *file, unsigned cmd, unsigned long arg) |
1da177e4 | 1676 | { |
4ebb16ca | 1677 | struct block_device *bdev = I_BDEV(bdev_file_inode(file)); |
56b26add | 1678 | fmode_t mode = file->f_mode; |
fd4ce1ac CH |
1679 | |
1680 | /* | |
1681 | * O_NDELAY can be altered using fcntl(.., F_SETFL, ..), so we have | |
1682 | * to updated it before every ioctl. | |
1683 | */ | |
56b26add | 1684 | if (file->f_flags & O_NDELAY) |
fd4ce1ac CH |
1685 | mode |= FMODE_NDELAY; |
1686 | else | |
1687 | mode &= ~FMODE_NDELAY; | |
1688 | ||
56b26add | 1689 | return blkdev_ioctl(bdev, mode, cmd, arg); |
1da177e4 LT |
1690 | } |
1691 | ||
eef99380 CH |
1692 | /* |
1693 | * Write data to the block device. Only intended for the block device itself | |
1694 | * and the raw driver which basically is a fake block device. | |
1695 | * | |
1696 | * Does not take i_mutex for the write and thus is not for general purpose | |
1697 | * use. | |
1698 | */ | |
1456c0a8 | 1699 | ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from) |
eef99380 CH |
1700 | { |
1701 | struct file *file = iocb->ki_filp; | |
4ebb16ca | 1702 | struct inode *bd_inode = bdev_file_inode(file); |
7ec7b94a | 1703 | loff_t size = i_size_read(bd_inode); |
53362a05 | 1704 | struct blk_plug plug; |
eef99380 | 1705 | ssize_t ret; |
5f380c7f | 1706 | |
7ec7b94a AV |
1707 | if (bdev_read_only(I_BDEV(bd_inode))) |
1708 | return -EPERM; | |
5f380c7f | 1709 | |
7ec7b94a | 1710 | if (!iov_iter_count(from)) |
5f380c7f AV |
1711 | return 0; |
1712 | ||
7ec7b94a AV |
1713 | if (iocb->ki_pos >= size) |
1714 | return -ENOSPC; | |
1715 | ||
1716 | iov_iter_truncate(from, size - iocb->ki_pos); | |
eef99380 | 1717 | |
53362a05 | 1718 | blk_start_plug(&plug); |
1456c0a8 | 1719 | ret = __generic_file_write_iter(iocb, from); |
02afc27f | 1720 | if (ret > 0) { |
eef99380 | 1721 | ssize_t err; |
1456c0a8 | 1722 | err = generic_write_sync(file, iocb->ki_pos - ret, ret); |
45d4f855 | 1723 | if (err < 0) |
eef99380 CH |
1724 | ret = err; |
1725 | } | |
53362a05 | 1726 | blk_finish_plug(&plug); |
eef99380 CH |
1727 | return ret; |
1728 | } | |
1456c0a8 | 1729 | EXPORT_SYMBOL_GPL(blkdev_write_iter); |
eef99380 | 1730 | |
b2de525f | 1731 | ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to) |
684c9aae LT |
1732 | { |
1733 | struct file *file = iocb->ki_filp; | |
4ebb16ca | 1734 | struct inode *bd_inode = bdev_file_inode(file); |
684c9aae | 1735 | loff_t size = i_size_read(bd_inode); |
a886038b | 1736 | loff_t pos = iocb->ki_pos; |
684c9aae LT |
1737 | |
1738 | if (pos >= size) | |
1739 | return 0; | |
1740 | ||
1741 | size -= pos; | |
a886038b AV |
1742 | iov_iter_truncate(to, size); |
1743 | return generic_file_read_iter(iocb, to); | |
684c9aae | 1744 | } |
b2de525f | 1745 | EXPORT_SYMBOL_GPL(blkdev_read_iter); |
684c9aae | 1746 | |
87d8fe1e TT |
1747 | /* |
1748 | * Try to release a page associated with block device when the system | |
1749 | * is under memory pressure. | |
1750 | */ | |
1751 | static int blkdev_releasepage(struct page *page, gfp_t wait) | |
1752 | { | |
1753 | struct super_block *super = BDEV_I(page->mapping->host)->bdev.bd_super; | |
1754 | ||
1755 | if (super && super->s_op->bdev_try_to_free_page) | |
1756 | return super->s_op->bdev_try_to_free_page(super, page, wait); | |
1757 | ||
1758 | return try_to_free_buffers(page); | |
1759 | } | |
1760 | ||
7f6d5b52 RZ |
1761 | static int blkdev_writepages(struct address_space *mapping, |
1762 | struct writeback_control *wbc) | |
1763 | { | |
1764 | if (dax_mapping(mapping)) { | |
1765 | struct block_device *bdev = I_BDEV(mapping->host); | |
1766 | ||
1767 | return dax_writeback_mapping_range(mapping, bdev, wbc); | |
1768 | } | |
1769 | return generic_writepages(mapping, wbc); | |
1770 | } | |
1771 | ||
4c54ac62 | 1772 | static const struct address_space_operations def_blk_aops = { |
1da177e4 | 1773 | .readpage = blkdev_readpage, |
447f05bb | 1774 | .readpages = blkdev_readpages, |
1da177e4 | 1775 | .writepage = blkdev_writepage, |
6272b5a5 NP |
1776 | .write_begin = blkdev_write_begin, |
1777 | .write_end = blkdev_write_end, | |
7f6d5b52 | 1778 | .writepages = blkdev_writepages, |
87d8fe1e | 1779 | .releasepage = blkdev_releasepage, |
1da177e4 | 1780 | .direct_IO = blkdev_direct_IO, |
b4597226 | 1781 | .is_dirty_writeback = buffer_check_dirty_writeback, |
1da177e4 LT |
1782 | }; |
1783 | ||
5a023cdb DW |
1784 | #ifdef CONFIG_FS_DAX |
1785 | /* | |
1786 | * In the raw block case we do not need to contend with truncation nor | |
1787 | * unwritten file extents. Without those concerns there is no need for | |
1788 | * additional locking beyond the mmap_sem context that these routines | |
1789 | * are already executing under. | |
1790 | * | |
1791 | * Note, there is no protection if the block device is dynamically | |
1792 | * resized (partition grow/shrink) during a fault. A stable block device | |
1793 | * size is already not enforced in the blkdev_direct_IO path. | |
1794 | * | |
1795 | * For DAX, it is the responsibility of the block device driver to | |
1796 | * ensure the whole-disk device size is stable while requests are in | |
1797 | * flight. | |
1798 | * | |
1799 | * Finally, unlike the filemap_page_mkwrite() case there is no | |
1800 | * filesystem superblock to sync against freezing. We still include a | |
1801 | * pfn_mkwrite callback for dax drivers to receive write fault | |
1802 | * notifications. | |
1803 | */ | |
1804 | static int blkdev_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf) | |
1805 | { | |
02fbd139 | 1806 | return __dax_fault(vma, vmf, blkdev_get_block); |
5a023cdb DW |
1807 | } |
1808 | ||
9c5a05bc RZ |
1809 | static int blkdev_dax_pfn_mkwrite(struct vm_area_struct *vma, |
1810 | struct vm_fault *vmf) | |
1811 | { | |
1812 | return dax_pfn_mkwrite(vma, vmf); | |
1813 | } | |
1814 | ||
5a023cdb DW |
1815 | static int blkdev_dax_pmd_fault(struct vm_area_struct *vma, unsigned long addr, |
1816 | pmd_t *pmd, unsigned int flags) | |
1817 | { | |
02fbd139 | 1818 | return __dax_pmd_fault(vma, addr, pmd, flags, blkdev_get_block); |
5a023cdb DW |
1819 | } |
1820 | ||
5a023cdb | 1821 | static const struct vm_operations_struct blkdev_dax_vm_ops = { |
5a023cdb DW |
1822 | .fault = blkdev_dax_fault, |
1823 | .pmd_fault = blkdev_dax_pmd_fault, | |
9c5a05bc | 1824 | .pfn_mkwrite = blkdev_dax_pfn_mkwrite, |
5a023cdb DW |
1825 | }; |
1826 | ||
1827 | static const struct vm_operations_struct blkdev_default_vm_ops = { | |
5a023cdb DW |
1828 | .fault = filemap_fault, |
1829 | .map_pages = filemap_map_pages, | |
1830 | }; | |
1831 | ||
1832 | static int blkdev_mmap(struct file *file, struct vm_area_struct *vma) | |
1833 | { | |
1834 | struct inode *bd_inode = bdev_file_inode(file); | |
5a023cdb DW |
1835 | |
1836 | file_accessed(file); | |
5a023cdb DW |
1837 | if (IS_DAX(bd_inode)) { |
1838 | vma->vm_ops = &blkdev_dax_vm_ops; | |
1839 | vma->vm_flags |= VM_MIXEDMAP | VM_HUGEPAGE; | |
1840 | } else { | |
1841 | vma->vm_ops = &blkdev_default_vm_ops; | |
1842 | } | |
5a023cdb DW |
1843 | |
1844 | return 0; | |
1845 | } | |
1846 | #else | |
1847 | #define blkdev_mmap generic_file_mmap | |
1848 | #endif | |
1849 | ||
4b6f5d20 | 1850 | const struct file_operations def_blk_fops = { |
1da177e4 LT |
1851 | .open = blkdev_open, |
1852 | .release = blkdev_close, | |
1853 | .llseek = block_llseek, | |
a886038b | 1854 | .read_iter = blkdev_read_iter, |
1456c0a8 | 1855 | .write_iter = blkdev_write_iter, |
5a023cdb | 1856 | .mmap = blkdev_mmap, |
b1dd3b28 | 1857 | .fsync = blkdev_fsync, |
bb93e3a5 | 1858 | .unlocked_ioctl = block_ioctl, |
1da177e4 LT |
1859 | #ifdef CONFIG_COMPAT |
1860 | .compat_ioctl = compat_blkdev_ioctl, | |
1861 | #endif | |
1e8b3332 | 1862 | .splice_read = generic_file_splice_read, |
8d020765 | 1863 | .splice_write = iter_file_splice_write, |
1da177e4 LT |
1864 | }; |
1865 | ||
1866 | int ioctl_by_bdev(struct block_device *bdev, unsigned cmd, unsigned long arg) | |
1867 | { | |
1868 | int res; | |
1869 | mm_segment_t old_fs = get_fs(); | |
1870 | set_fs(KERNEL_DS); | |
56b26add | 1871 | res = blkdev_ioctl(bdev, 0, cmd, arg); |
1da177e4 LT |
1872 | set_fs(old_fs); |
1873 | return res; | |
1874 | } | |
1875 | ||
1876 | EXPORT_SYMBOL(ioctl_by_bdev); | |
1877 | ||
1878 | /** | |
1879 | * lookup_bdev - lookup a struct block_device by name | |
94e2959e | 1880 | * @pathname: special file representing the block device |
1da177e4 | 1881 | * |
57d1b536 | 1882 | * Get a reference to the blockdevice at @pathname in the current |
1da177e4 LT |
1883 | * namespace if possible and return it. Return ERR_PTR(error) |
1884 | * otherwise. | |
1885 | */ | |
421748ec | 1886 | struct block_device *lookup_bdev(const char *pathname) |
1da177e4 LT |
1887 | { |
1888 | struct block_device *bdev; | |
1889 | struct inode *inode; | |
421748ec | 1890 | struct path path; |
1da177e4 LT |
1891 | int error; |
1892 | ||
421748ec | 1893 | if (!pathname || !*pathname) |
1da177e4 LT |
1894 | return ERR_PTR(-EINVAL); |
1895 | ||
421748ec | 1896 | error = kern_path(pathname, LOOKUP_FOLLOW, &path); |
1da177e4 LT |
1897 | if (error) |
1898 | return ERR_PTR(error); | |
1899 | ||
bb668734 | 1900 | inode = d_backing_inode(path.dentry); |
1da177e4 LT |
1901 | error = -ENOTBLK; |
1902 | if (!S_ISBLK(inode->i_mode)) | |
1903 | goto fail; | |
1904 | error = -EACCES; | |
421748ec | 1905 | if (path.mnt->mnt_flags & MNT_NODEV) |
1da177e4 LT |
1906 | goto fail; |
1907 | error = -ENOMEM; | |
1908 | bdev = bd_acquire(inode); | |
1909 | if (!bdev) | |
1910 | goto fail; | |
1911 | out: | |
421748ec | 1912 | path_put(&path); |
1da177e4 LT |
1913 | return bdev; |
1914 | fail: | |
1915 | bdev = ERR_PTR(error); | |
1916 | goto out; | |
1917 | } | |
d5686b44 | 1918 | EXPORT_SYMBOL(lookup_bdev); |
1da177e4 | 1919 | |
93b270f7 | 1920 | int __invalidate_device(struct block_device *bdev, bool kill_dirty) |
b71e8a4c DH |
1921 | { |
1922 | struct super_block *sb = get_super(bdev); | |
1923 | int res = 0; | |
1924 | ||
1925 | if (sb) { | |
1926 | /* | |
1927 | * no need to lock the super, get_super holds the | |
1928 | * read mutex so the filesystem cannot go away | |
1929 | * under us (->put_super runs with the write lock | |
1930 | * hold). | |
1931 | */ | |
1932 | shrink_dcache_sb(sb); | |
93b270f7 | 1933 | res = invalidate_inodes(sb, kill_dirty); |
b71e8a4c DH |
1934 | drop_super(sb); |
1935 | } | |
f98393a6 | 1936 | invalidate_bdev(bdev); |
b71e8a4c DH |
1937 | return res; |
1938 | } | |
1939 | EXPORT_SYMBOL(__invalidate_device); | |
5c0d6b60 JK |
1940 | |
1941 | void iterate_bdevs(void (*func)(struct block_device *, void *), void *arg) | |
1942 | { | |
1943 | struct inode *inode, *old_inode = NULL; | |
1944 | ||
74278da9 | 1945 | spin_lock(&blockdev_superblock->s_inode_list_lock); |
5c0d6b60 JK |
1946 | list_for_each_entry(inode, &blockdev_superblock->s_inodes, i_sb_list) { |
1947 | struct address_space *mapping = inode->i_mapping; | |
1948 | ||
1949 | spin_lock(&inode->i_lock); | |
1950 | if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW) || | |
1951 | mapping->nrpages == 0) { | |
1952 | spin_unlock(&inode->i_lock); | |
1953 | continue; | |
1954 | } | |
1955 | __iget(inode); | |
1956 | spin_unlock(&inode->i_lock); | |
74278da9 | 1957 | spin_unlock(&blockdev_superblock->s_inode_list_lock); |
5c0d6b60 JK |
1958 | /* |
1959 | * We hold a reference to 'inode' so it couldn't have been | |
1960 | * removed from s_inodes list while we dropped the | |
74278da9 | 1961 | * s_inode_list_lock We cannot iput the inode now as we can |
5c0d6b60 | 1962 | * be holding the last reference and we cannot iput it under |
74278da9 | 1963 | * s_inode_list_lock. So we keep the reference and iput it |
5c0d6b60 JK |
1964 | * later. |
1965 | */ | |
1966 | iput(old_inode); | |
1967 | old_inode = inode; | |
1968 | ||
1969 | func(I_BDEV(inode), arg); | |
1970 | ||
74278da9 | 1971 | spin_lock(&blockdev_superblock->s_inode_list_lock); |
5c0d6b60 | 1972 | } |
74278da9 | 1973 | spin_unlock(&blockdev_superblock->s_inode_list_lock); |
5c0d6b60 JK |
1974 | iput(old_inode); |
1975 | } |