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1 | /* | |
2 | * linux/fs/block_dev.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | * Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE | |
6 | */ | |
7 | ||
8 | #include <linux/init.h> | |
9 | #include <linux/mm.h> | |
10 | #include <linux/fcntl.h> | |
11 | #include <linux/slab.h> | |
12 | #include <linux/kmod.h> | |
13 | #include <linux/major.h> | |
14 | #include <linux/device_cgroup.h> | |
15 | #include <linux/highmem.h> | |
16 | #include <linux/blkdev.h> | |
17 | #include <linux/backing-dev.h> | |
18 | #include <linux/module.h> | |
19 | #include <linux/blkpg.h> | |
20 | #include <linux/magic.h> | |
21 | #include <linux/buffer_head.h> | |
22 | #include <linux/swap.h> | |
23 | #include <linux/pagevec.h> | |
24 | #include <linux/writeback.h> | |
25 | #include <linux/mpage.h> | |
26 | #include <linux/mount.h> | |
27 | #include <linux/uio.h> | |
28 | #include <linux/namei.h> | |
29 | #include <linux/log2.h> | |
30 | #include <linux/cleancache.h> | |
31 | #include <linux/dax.h> | |
32 | #include <asm/uaccess.h> | |
33 | #include "internal.h" | |
34 | ||
35 | struct bdev_inode { | |
36 | struct block_device bdev; | |
37 | struct inode vfs_inode; | |
38 | }; | |
39 | ||
40 | static const struct address_space_operations def_blk_aops; | |
41 | ||
42 | static inline struct bdev_inode *BDEV_I(struct inode *inode) | |
43 | { | |
44 | return container_of(inode, struct bdev_inode, vfs_inode); | |
45 | } | |
46 | ||
47 | struct block_device *I_BDEV(struct inode *inode) | |
48 | { | |
49 | return &BDEV_I(inode)->bdev; | |
50 | } | |
51 | EXPORT_SYMBOL(I_BDEV); | |
52 | ||
53 | static void bdev_write_inode(struct block_device *bdev) | |
54 | { | |
55 | struct inode *inode = bdev->bd_inode; | |
56 | int ret; | |
57 | ||
58 | spin_lock(&inode->i_lock); | |
59 | while (inode->i_state & I_DIRTY) { | |
60 | spin_unlock(&inode->i_lock); | |
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 | } | |
68 | spin_lock(&inode->i_lock); | |
69 | } | |
70 | spin_unlock(&inode->i_lock); | |
71 | } | |
72 | ||
73 | /* Kill _all_ buffers and pagecache , dirty or not.. */ | |
74 | void kill_bdev(struct block_device *bdev) | |
75 | { | |
76 | struct address_space *mapping = bdev->bd_inode->i_mapping; | |
77 | ||
78 | if (mapping->nrpages == 0 && mapping->nrexceptional == 0) | |
79 | return; | |
80 | ||
81 | invalidate_bh_lrus(); | |
82 | truncate_inode_pages(mapping, 0); | |
83 | } | |
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 | ||
91 | if (mapping->nrpages == 0) | |
92 | return; | |
93 | ||
94 | invalidate_bh_lrus(); | |
95 | lru_add_drain_all(); /* make sure all lru add caches are flushed */ | |
96 | invalidate_mapping_pages(mapping, 0, -1); | |
97 | /* 99% of the time, we don't need to flush the cleancache on the bdev. | |
98 | * But, for the strange corners, lets be cautious | |
99 | */ | |
100 | cleancache_invalidate_inode(mapping); | |
101 | } | |
102 | EXPORT_SYMBOL(invalidate_bdev); | |
103 | ||
104 | int set_blocksize(struct block_device *bdev, int size) | |
105 | { | |
106 | /* Size must be a power of two, and between 512 and PAGE_SIZE */ | |
107 | if (size > PAGE_SIZE || size < 512 || !is_power_of_2(size)) | |
108 | return -EINVAL; | |
109 | ||
110 | /* Size cannot be smaller than the size supported by the device */ | |
111 | if (size < bdev_logical_block_size(bdev)) | |
112 | return -EINVAL; | |
113 | ||
114 | /* Don't change the size if it is same as current */ | |
115 | if (bdev->bd_block_size != size) { | |
116 | sync_blockdev(bdev); | |
117 | bdev->bd_block_size = size; | |
118 | bdev->bd_inode->i_blkbits = blksize_bits(size); | |
119 | kill_bdev(bdev); | |
120 | } | |
121 | return 0; | |
122 | } | |
123 | ||
124 | EXPORT_SYMBOL(set_blocksize); | |
125 | ||
126 | int sb_set_blocksize(struct super_block *sb, int size) | |
127 | { | |
128 | if (set_blocksize(sb->s_bdev, size)) | |
129 | return 0; | |
130 | /* If we get here, we know size is power of two | |
131 | * and it's value is between 512 and PAGE_SIZE */ | |
132 | sb->s_blocksize = size; | |
133 | sb->s_blocksize_bits = blksize_bits(size); | |
134 | return sb->s_blocksize; | |
135 | } | |
136 | ||
137 | EXPORT_SYMBOL(sb_set_blocksize); | |
138 | ||
139 | int sb_min_blocksize(struct super_block *sb, int size) | |
140 | { | |
141 | int minsize = bdev_logical_block_size(sb->s_bdev); | |
142 | if (size < minsize) | |
143 | size = minsize; | |
144 | return sb_set_blocksize(sb, size); | |
145 | } | |
146 | ||
147 | EXPORT_SYMBOL(sb_min_blocksize); | |
148 | ||
149 | static int | |
150 | blkdev_get_block(struct inode *inode, sector_t iblock, | |
151 | struct buffer_head *bh, int create) | |
152 | { | |
153 | bh->b_bdev = I_BDEV(inode); | |
154 | bh->b_blocknr = iblock; | |
155 | set_buffer_mapped(bh); | |
156 | return 0; | |
157 | } | |
158 | ||
159 | static struct inode *bdev_file_inode(struct file *file) | |
160 | { | |
161 | return file->f_mapping->host; | |
162 | } | |
163 | ||
164 | static ssize_t | |
165 | blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, loff_t offset) | |
166 | { | |
167 | struct file *file = iocb->ki_filp; | |
168 | struct inode *inode = bdev_file_inode(file); | |
169 | ||
170 | if (IS_DAX(inode)) | |
171 | return dax_do_io(iocb, inode, iter, offset, blkdev_get_block, | |
172 | NULL, DIO_SKIP_DIO_COUNT); | |
173 | return __blockdev_direct_IO(iocb, inode, I_BDEV(inode), iter, offset, | |
174 | blkdev_get_block, NULL, NULL, | |
175 | DIO_SKIP_DIO_COUNT); | |
176 | } | |
177 | ||
178 | int __sync_blockdev(struct block_device *bdev, int wait) | |
179 | { | |
180 | if (!bdev) | |
181 | return 0; | |
182 | if (!wait) | |
183 | return filemap_flush(bdev->bd_inode->i_mapping); | |
184 | return filemap_write_and_wait(bdev->bd_inode->i_mapping); | |
185 | } | |
186 | ||
187 | /* | |
188 | * Write out and wait upon all the dirty data associated with a block | |
189 | * device via its mapping. Does not take the superblock lock. | |
190 | */ | |
191 | int sync_blockdev(struct block_device *bdev) | |
192 | { | |
193 | return __sync_blockdev(bdev, 1); | |
194 | } | |
195 | EXPORT_SYMBOL(sync_blockdev); | |
196 | ||
197 | /* | |
198 | * Write out and wait upon all dirty data associated with this | |
199 | * device. Filesystem data as well as the underlying block | |
200 | * device. Takes the superblock lock. | |
201 | */ | |
202 | int fsync_bdev(struct block_device *bdev) | |
203 | { | |
204 | struct super_block *sb = get_super(bdev); | |
205 | if (sb) { | |
206 | int res = sync_filesystem(sb); | |
207 | drop_super(sb); | |
208 | return res; | |
209 | } | |
210 | return sync_blockdev(bdev); | |
211 | } | |
212 | EXPORT_SYMBOL(fsync_bdev); | |
213 | ||
214 | /** | |
215 | * freeze_bdev -- lock a filesystem and force it into a consistent state | |
216 | * @bdev: blockdevice to lock | |
217 | * | |
218 | * If a superblock is found on this device, we take the s_umount semaphore | |
219 | * on it to make sure nobody unmounts until the snapshot creation is done. | |
220 | * The reference counter (bd_fsfreeze_count) guarantees that only the last | |
221 | * unfreeze process can unfreeze the frozen filesystem actually when multiple | |
222 | * freeze requests arrive simultaneously. It counts up in freeze_bdev() and | |
223 | * count down in thaw_bdev(). When it becomes 0, thaw_bdev() will unfreeze | |
224 | * actually. | |
225 | */ | |
226 | struct super_block *freeze_bdev(struct block_device *bdev) | |
227 | { | |
228 | struct super_block *sb; | |
229 | int error = 0; | |
230 | ||
231 | mutex_lock(&bdev->bd_fsfreeze_mutex); | |
232 | if (++bdev->bd_fsfreeze_count > 1) { | |
233 | /* | |
234 | * We don't even need to grab a reference - the first call | |
235 | * to freeze_bdev grab an active reference and only the last | |
236 | * thaw_bdev drops it. | |
237 | */ | |
238 | sb = get_super(bdev); | |
239 | drop_super(sb); | |
240 | mutex_unlock(&bdev->bd_fsfreeze_mutex); | |
241 | return sb; | |
242 | } | |
243 | ||
244 | sb = get_active_super(bdev); | |
245 | if (!sb) | |
246 | goto out; | |
247 | if (sb->s_op->freeze_super) | |
248 | error = sb->s_op->freeze_super(sb); | |
249 | else | |
250 | error = freeze_super(sb); | |
251 | if (error) { | |
252 | deactivate_super(sb); | |
253 | bdev->bd_fsfreeze_count--; | |
254 | mutex_unlock(&bdev->bd_fsfreeze_mutex); | |
255 | return ERR_PTR(error); | |
256 | } | |
257 | deactivate_super(sb); | |
258 | out: | |
259 | sync_blockdev(bdev); | |
260 | mutex_unlock(&bdev->bd_fsfreeze_mutex); | |
261 | return sb; /* thaw_bdev releases s->s_umount */ | |
262 | } | |
263 | EXPORT_SYMBOL(freeze_bdev); | |
264 | ||
265 | /** | |
266 | * thaw_bdev -- unlock filesystem | |
267 | * @bdev: blockdevice to unlock | |
268 | * @sb: associated superblock | |
269 | * | |
270 | * Unlocks the filesystem and marks it writeable again after freeze_bdev(). | |
271 | */ | |
272 | int thaw_bdev(struct block_device *bdev, struct super_block *sb) | |
273 | { | |
274 | int error = -EINVAL; | |
275 | ||
276 | mutex_lock(&bdev->bd_fsfreeze_mutex); | |
277 | if (!bdev->bd_fsfreeze_count) | |
278 | goto out; | |
279 | ||
280 | error = 0; | |
281 | if (--bdev->bd_fsfreeze_count > 0) | |
282 | goto out; | |
283 | ||
284 | if (!sb) | |
285 | goto out; | |
286 | ||
287 | if (sb->s_op->thaw_super) | |
288 | error = sb->s_op->thaw_super(sb); | |
289 | else | |
290 | error = thaw_super(sb); | |
291 | if (error) { | |
292 | bdev->bd_fsfreeze_count++; | |
293 | mutex_unlock(&bdev->bd_fsfreeze_mutex); | |
294 | return error; | |
295 | } | |
296 | out: | |
297 | mutex_unlock(&bdev->bd_fsfreeze_mutex); | |
298 | return 0; | |
299 | } | |
300 | EXPORT_SYMBOL(thaw_bdev); | |
301 | ||
302 | static int blkdev_writepage(struct page *page, struct writeback_control *wbc) | |
303 | { | |
304 | return block_write_full_page(page, blkdev_get_block, wbc); | |
305 | } | |
306 | ||
307 | static int blkdev_readpage(struct file * file, struct page * page) | |
308 | { | |
309 | return block_read_full_page(page, blkdev_get_block); | |
310 | } | |
311 | ||
312 | static int blkdev_readpages(struct file *file, struct address_space *mapping, | |
313 | struct list_head *pages, unsigned nr_pages) | |
314 | { | |
315 | return mpage_readpages(mapping, pages, nr_pages, blkdev_get_block); | |
316 | } | |
317 | ||
318 | static int blkdev_write_begin(struct file *file, struct address_space *mapping, | |
319 | loff_t pos, unsigned len, unsigned flags, | |
320 | struct page **pagep, void **fsdata) | |
321 | { | |
322 | return block_write_begin(mapping, pos, len, flags, pagep, | |
323 | blkdev_get_block); | |
324 | } | |
325 | ||
326 | static int blkdev_write_end(struct file *file, struct address_space *mapping, | |
327 | loff_t pos, unsigned len, unsigned copied, | |
328 | struct page *page, void *fsdata) | |
329 | { | |
330 | int ret; | |
331 | ret = block_write_end(file, mapping, pos, len, copied, page, fsdata); | |
332 | ||
333 | unlock_page(page); | |
334 | put_page(page); | |
335 | ||
336 | return ret; | |
337 | } | |
338 | ||
339 | /* | |
340 | * private llseek: | |
341 | * for a block special file file_inode(file)->i_size is zero | |
342 | * so we compute the size by hand (just as in block_read/write above) | |
343 | */ | |
344 | static loff_t block_llseek(struct file *file, loff_t offset, int whence) | |
345 | { | |
346 | struct inode *bd_inode = bdev_file_inode(file); | |
347 | loff_t retval; | |
348 | ||
349 | inode_lock(bd_inode); | |
350 | retval = fixed_size_llseek(file, offset, whence, i_size_read(bd_inode)); | |
351 | inode_unlock(bd_inode); | |
352 | return retval; | |
353 | } | |
354 | ||
355 | int blkdev_fsync(struct file *filp, loff_t start, loff_t end, int datasync) | |
356 | { | |
357 | struct inode *bd_inode = bdev_file_inode(filp); | |
358 | struct block_device *bdev = I_BDEV(bd_inode); | |
359 | int error; | |
360 | ||
361 | error = filemap_write_and_wait_range(filp->f_mapping, start, end); | |
362 | if (error) | |
363 | return error; | |
364 | ||
365 | /* | |
366 | * There is no need to serialise calls to blkdev_issue_flush with | |
367 | * i_mutex and doing so causes performance issues with concurrent | |
368 | * O_SYNC writers to a block device. | |
369 | */ | |
370 | error = blkdev_issue_flush(bdev, GFP_KERNEL, NULL); | |
371 | if (error == -EOPNOTSUPP) | |
372 | error = 0; | |
373 | ||
374 | return error; | |
375 | } | |
376 | EXPORT_SYMBOL(blkdev_fsync); | |
377 | ||
378 | /** | |
379 | * bdev_read_page() - Start reading a page from a block device | |
380 | * @bdev: The device to read the page from | |
381 | * @sector: The offset on the device to read the page to (need not be aligned) | |
382 | * @page: The page to read | |
383 | * | |
384 | * On entry, the page should be locked. It will be unlocked when the page | |
385 | * has been read. If the block driver implements rw_page synchronously, | |
386 | * that will be true on exit from this function, but it need not be. | |
387 | * | |
388 | * Errors returned by this function are usually "soft", eg out of memory, or | |
389 | * queue full; callers should try a different route to read this page rather | |
390 | * than propagate an error back up the stack. | |
391 | * | |
392 | * Return: negative errno if an error occurs, 0 if submission was successful. | |
393 | */ | |
394 | int bdev_read_page(struct block_device *bdev, sector_t sector, | |
395 | struct page *page) | |
396 | { | |
397 | const struct block_device_operations *ops = bdev->bd_disk->fops; | |
398 | int result = -EOPNOTSUPP; | |
399 | ||
400 | if (!ops->rw_page || bdev_get_integrity(bdev)) | |
401 | return result; | |
402 | ||
403 | result = blk_queue_enter(bdev->bd_queue, false); | |
404 | if (result) | |
405 | return result; | |
406 | result = ops->rw_page(bdev, sector + get_start_sect(bdev), page, READ); | |
407 | blk_queue_exit(bdev->bd_queue); | |
408 | return result; | |
409 | } | |
410 | EXPORT_SYMBOL_GPL(bdev_read_page); | |
411 | ||
412 | /** | |
413 | * bdev_write_page() - Start writing a page to a block device | |
414 | * @bdev: The device to write the page to | |
415 | * @sector: The offset on the device to write the page to (need not be aligned) | |
416 | * @page: The page to write | |
417 | * @wbc: The writeback_control for the write | |
418 | * | |
419 | * On entry, the page should be locked and not currently under writeback. | |
420 | * On exit, if the write started successfully, the page will be unlocked and | |
421 | * under writeback. If the write failed already (eg the driver failed to | |
422 | * queue the page to the device), the page will still be locked. If the | |
423 | * caller is a ->writepage implementation, it will need to unlock the page. | |
424 | * | |
425 | * Errors returned by this function are usually "soft", eg out of memory, or | |
426 | * queue full; callers should try a different route to write this page rather | |
427 | * than propagate an error back up the stack. | |
428 | * | |
429 | * Return: negative errno if an error occurs, 0 if submission was successful. | |
430 | */ | |
431 | int bdev_write_page(struct block_device *bdev, sector_t sector, | |
432 | struct page *page, struct writeback_control *wbc) | |
433 | { | |
434 | int result; | |
435 | int rw = (wbc->sync_mode == WB_SYNC_ALL) ? WRITE_SYNC : WRITE; | |
436 | const struct block_device_operations *ops = bdev->bd_disk->fops; | |
437 | ||
438 | if (!ops->rw_page || bdev_get_integrity(bdev)) | |
439 | return -EOPNOTSUPP; | |
440 | result = blk_queue_enter(bdev->bd_queue, false); | |
441 | if (result) | |
442 | return result; | |
443 | ||
444 | set_page_writeback(page); | |
445 | result = ops->rw_page(bdev, sector + get_start_sect(bdev), page, rw); | |
446 | if (result) | |
447 | end_page_writeback(page); | |
448 | else | |
449 | unlock_page(page); | |
450 | blk_queue_exit(bdev->bd_queue); | |
451 | return result; | |
452 | } | |
453 | EXPORT_SYMBOL_GPL(bdev_write_page); | |
454 | ||
455 | /** | |
456 | * bdev_direct_access() - Get the address for directly-accessibly memory | |
457 | * @bdev: The device containing the memory | |
458 | * @dax: control and output parameters for ->direct_access | |
459 | * | |
460 | * If a block device is made up of directly addressable memory, this function | |
461 | * will tell the caller the PFN and the address of the memory. The address | |
462 | * may be directly dereferenced within the kernel without the need to call | |
463 | * ioremap(), kmap() or similar. The PFN is suitable for inserting into | |
464 | * page tables. | |
465 | * | |
466 | * Return: negative errno if an error occurs, otherwise the number of bytes | |
467 | * accessible at this address. | |
468 | */ | |
469 | long bdev_direct_access(struct block_device *bdev, struct blk_dax_ctl *dax) | |
470 | { | |
471 | sector_t sector = dax->sector; | |
472 | long avail, size = dax->size; | |
473 | const struct block_device_operations *ops = bdev->bd_disk->fops; | |
474 | ||
475 | /* | |
476 | * The device driver is allowed to sleep, in order to make the | |
477 | * memory directly accessible. | |
478 | */ | |
479 | might_sleep(); | |
480 | ||
481 | if (size < 0) | |
482 | return size; | |
483 | if (!ops->direct_access) | |
484 | return -EOPNOTSUPP; | |
485 | if ((sector + DIV_ROUND_UP(size, 512)) > | |
486 | part_nr_sects_read(bdev->bd_part)) | |
487 | return -ERANGE; | |
488 | sector += get_start_sect(bdev); | |
489 | if (sector % (PAGE_SIZE / 512)) | |
490 | return -EINVAL; | |
491 | avail = ops->direct_access(bdev, sector, &dax->addr, &dax->pfn); | |
492 | if (!avail) | |
493 | return -ERANGE; | |
494 | if (avail > 0 && avail & ~PAGE_MASK) | |
495 | return -ENXIO; | |
496 | return min(avail, size); | |
497 | } | |
498 | EXPORT_SYMBOL_GPL(bdev_direct_access); | |
499 | ||
500 | /* | |
501 | * pseudo-fs | |
502 | */ | |
503 | ||
504 | static __cacheline_aligned_in_smp DEFINE_SPINLOCK(bdev_lock); | |
505 | static struct kmem_cache * bdev_cachep __read_mostly; | |
506 | ||
507 | static struct inode *bdev_alloc_inode(struct super_block *sb) | |
508 | { | |
509 | struct bdev_inode *ei = kmem_cache_alloc(bdev_cachep, GFP_KERNEL); | |
510 | if (!ei) | |
511 | return NULL; | |
512 | return &ei->vfs_inode; | |
513 | } | |
514 | ||
515 | static void bdev_i_callback(struct rcu_head *head) | |
516 | { | |
517 | struct inode *inode = container_of(head, struct inode, i_rcu); | |
518 | struct bdev_inode *bdi = BDEV_I(inode); | |
519 | ||
520 | kmem_cache_free(bdev_cachep, bdi); | |
521 | } | |
522 | ||
523 | static void bdev_destroy_inode(struct inode *inode) | |
524 | { | |
525 | call_rcu(&inode->i_rcu, bdev_i_callback); | |
526 | } | |
527 | ||
528 | static void init_once(void *foo) | |
529 | { | |
530 | struct bdev_inode *ei = (struct bdev_inode *) foo; | |
531 | struct block_device *bdev = &ei->bdev; | |
532 | ||
533 | memset(bdev, 0, sizeof(*bdev)); | |
534 | mutex_init(&bdev->bd_mutex); | |
535 | INIT_LIST_HEAD(&bdev->bd_inodes); | |
536 | INIT_LIST_HEAD(&bdev->bd_list); | |
537 | #ifdef CONFIG_SYSFS | |
538 | INIT_LIST_HEAD(&bdev->bd_holder_disks); | |
539 | #endif | |
540 | inode_init_once(&ei->vfs_inode); | |
541 | /* Initialize mutex for freeze. */ | |
542 | mutex_init(&bdev->bd_fsfreeze_mutex); | |
543 | } | |
544 | ||
545 | static inline void __bd_forget(struct inode *inode) | |
546 | { | |
547 | list_del_init(&inode->i_devices); | |
548 | inode->i_bdev = NULL; | |
549 | inode->i_mapping = &inode->i_data; | |
550 | } | |
551 | ||
552 | static void bdev_evict_inode(struct inode *inode) | |
553 | { | |
554 | struct block_device *bdev = &BDEV_I(inode)->bdev; | |
555 | struct list_head *p; | |
556 | truncate_inode_pages_final(&inode->i_data); | |
557 | invalidate_inode_buffers(inode); /* is it needed here? */ | |
558 | clear_inode(inode); | |
559 | spin_lock(&bdev_lock); | |
560 | while ( (p = bdev->bd_inodes.next) != &bdev->bd_inodes ) { | |
561 | __bd_forget(list_entry(p, struct inode, i_devices)); | |
562 | } | |
563 | list_del_init(&bdev->bd_list); | |
564 | spin_unlock(&bdev_lock); | |
565 | } | |
566 | ||
567 | static const struct super_operations bdev_sops = { | |
568 | .statfs = simple_statfs, | |
569 | .alloc_inode = bdev_alloc_inode, | |
570 | .destroy_inode = bdev_destroy_inode, | |
571 | .drop_inode = generic_delete_inode, | |
572 | .evict_inode = bdev_evict_inode, | |
573 | }; | |
574 | ||
575 | static struct dentry *bd_mount(struct file_system_type *fs_type, | |
576 | int flags, const char *dev_name, void *data) | |
577 | { | |
578 | struct dentry *dent; | |
579 | dent = mount_pseudo(fs_type, "bdev:", &bdev_sops, NULL, BDEVFS_MAGIC); | |
580 | if (dent) | |
581 | dent->d_sb->s_iflags |= SB_I_CGROUPWB; | |
582 | return dent; | |
583 | } | |
584 | ||
585 | static struct file_system_type bd_type = { | |
586 | .name = "bdev", | |
587 | .mount = bd_mount, | |
588 | .kill_sb = kill_anon_super, | |
589 | }; | |
590 | ||
591 | struct super_block *blockdev_superblock __read_mostly; | |
592 | EXPORT_SYMBOL_GPL(blockdev_superblock); | |
593 | ||
594 | void __init bdev_cache_init(void) | |
595 | { | |
596 | int err; | |
597 | static struct vfsmount *bd_mnt; | |
598 | ||
599 | bdev_cachep = kmem_cache_create("bdev_cache", sizeof(struct bdev_inode), | |
600 | 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT| | |
601 | SLAB_MEM_SPREAD|SLAB_ACCOUNT|SLAB_PANIC), | |
602 | init_once); | |
603 | err = register_filesystem(&bd_type); | |
604 | if (err) | |
605 | panic("Cannot register bdev pseudo-fs"); | |
606 | bd_mnt = kern_mount(&bd_type); | |
607 | if (IS_ERR(bd_mnt)) | |
608 | panic("Cannot create bdev pseudo-fs"); | |
609 | blockdev_superblock = bd_mnt->mnt_sb; /* For writeback */ | |
610 | } | |
611 | ||
612 | /* | |
613 | * Most likely _very_ bad one - but then it's hardly critical for small | |
614 | * /dev and can be fixed when somebody will need really large one. | |
615 | * Keep in mind that it will be fed through icache hash function too. | |
616 | */ | |
617 | static inline unsigned long hash(dev_t dev) | |
618 | { | |
619 | return MAJOR(dev)+MINOR(dev); | |
620 | } | |
621 | ||
622 | static int bdev_test(struct inode *inode, void *data) | |
623 | { | |
624 | return BDEV_I(inode)->bdev.bd_dev == *(dev_t *)data; | |
625 | } | |
626 | ||
627 | static int bdev_set(struct inode *inode, void *data) | |
628 | { | |
629 | BDEV_I(inode)->bdev.bd_dev = *(dev_t *)data; | |
630 | return 0; | |
631 | } | |
632 | ||
633 | static LIST_HEAD(all_bdevs); | |
634 | ||
635 | struct block_device *bdget(dev_t dev) | |
636 | { | |
637 | struct block_device *bdev; | |
638 | struct inode *inode; | |
639 | ||
640 | inode = iget5_locked(blockdev_superblock, hash(dev), | |
641 | bdev_test, bdev_set, &dev); | |
642 | ||
643 | if (!inode) | |
644 | return NULL; | |
645 | ||
646 | bdev = &BDEV_I(inode)->bdev; | |
647 | ||
648 | if (inode->i_state & I_NEW) { | |
649 | bdev->bd_contains = NULL; | |
650 | bdev->bd_super = NULL; | |
651 | bdev->bd_inode = inode; | |
652 | bdev->bd_block_size = (1 << inode->i_blkbits); | |
653 | bdev->bd_part_count = 0; | |
654 | bdev->bd_invalidated = 0; | |
655 | inode->i_mode = S_IFBLK; | |
656 | inode->i_rdev = dev; | |
657 | inode->i_bdev = bdev; | |
658 | inode->i_data.a_ops = &def_blk_aops; | |
659 | mapping_set_gfp_mask(&inode->i_data, GFP_USER); | |
660 | spin_lock(&bdev_lock); | |
661 | list_add(&bdev->bd_list, &all_bdevs); | |
662 | spin_unlock(&bdev_lock); | |
663 | unlock_new_inode(inode); | |
664 | } | |
665 | return bdev; | |
666 | } | |
667 | ||
668 | EXPORT_SYMBOL(bdget); | |
669 | ||
670 | /** | |
671 | * bdgrab -- Grab a reference to an already referenced block device | |
672 | * @bdev: Block device to grab a reference to. | |
673 | */ | |
674 | struct block_device *bdgrab(struct block_device *bdev) | |
675 | { | |
676 | ihold(bdev->bd_inode); | |
677 | return bdev; | |
678 | } | |
679 | EXPORT_SYMBOL(bdgrab); | |
680 | ||
681 | long nr_blockdev_pages(void) | |
682 | { | |
683 | struct block_device *bdev; | |
684 | long ret = 0; | |
685 | spin_lock(&bdev_lock); | |
686 | list_for_each_entry(bdev, &all_bdevs, bd_list) { | |
687 | ret += bdev->bd_inode->i_mapping->nrpages; | |
688 | } | |
689 | spin_unlock(&bdev_lock); | |
690 | return ret; | |
691 | } | |
692 | ||
693 | void bdput(struct block_device *bdev) | |
694 | { | |
695 | iput(bdev->bd_inode); | |
696 | } | |
697 | ||
698 | EXPORT_SYMBOL(bdput); | |
699 | ||
700 | static struct block_device *bd_acquire(struct inode *inode) | |
701 | { | |
702 | struct block_device *bdev; | |
703 | ||
704 | spin_lock(&bdev_lock); | |
705 | bdev = inode->i_bdev; | |
706 | if (bdev) { | |
707 | bdgrab(bdev); | |
708 | spin_unlock(&bdev_lock); | |
709 | return bdev; | |
710 | } | |
711 | spin_unlock(&bdev_lock); | |
712 | ||
713 | bdev = bdget(inode->i_rdev); | |
714 | if (bdev) { | |
715 | spin_lock(&bdev_lock); | |
716 | if (!inode->i_bdev) { | |
717 | /* | |
718 | * We take an additional reference to bd_inode, | |
719 | * and it's released in clear_inode() of inode. | |
720 | * So, we can access it via ->i_mapping always | |
721 | * without igrab(). | |
722 | */ | |
723 | bdgrab(bdev); | |
724 | inode->i_bdev = bdev; | |
725 | inode->i_mapping = bdev->bd_inode->i_mapping; | |
726 | list_add(&inode->i_devices, &bdev->bd_inodes); | |
727 | } | |
728 | spin_unlock(&bdev_lock); | |
729 | } | |
730 | return bdev; | |
731 | } | |
732 | ||
733 | /* Call when you free inode */ | |
734 | ||
735 | void bd_forget(struct inode *inode) | |
736 | { | |
737 | struct block_device *bdev = NULL; | |
738 | ||
739 | spin_lock(&bdev_lock); | |
740 | if (!sb_is_blkdev_sb(inode->i_sb)) | |
741 | bdev = inode->i_bdev; | |
742 | __bd_forget(inode); | |
743 | spin_unlock(&bdev_lock); | |
744 | ||
745 | if (bdev) | |
746 | bdput(bdev); | |
747 | } | |
748 | ||
749 | /** | |
750 | * bd_may_claim - test whether a block device can be claimed | |
751 | * @bdev: block device of interest | |
752 | * @whole: whole block device containing @bdev, may equal @bdev | |
753 | * @holder: holder trying to claim @bdev | |
754 | * | |
755 | * Test whether @bdev can be claimed by @holder. | |
756 | * | |
757 | * CONTEXT: | |
758 | * spin_lock(&bdev_lock). | |
759 | * | |
760 | * RETURNS: | |
761 | * %true if @bdev can be claimed, %false otherwise. | |
762 | */ | |
763 | static bool bd_may_claim(struct block_device *bdev, struct block_device *whole, | |
764 | void *holder) | |
765 | { | |
766 | if (bdev->bd_holder == holder) | |
767 | return true; /* already a holder */ | |
768 | else if (bdev->bd_holder != NULL) | |
769 | return false; /* held by someone else */ | |
770 | else if (bdev->bd_contains == bdev) | |
771 | return true; /* is a whole device which isn't held */ | |
772 | ||
773 | else if (whole->bd_holder == bd_may_claim) | |
774 | return true; /* is a partition of a device that is being partitioned */ | |
775 | else if (whole->bd_holder != NULL) | |
776 | return false; /* is a partition of a held device */ | |
777 | else | |
778 | return true; /* is a partition of an un-held device */ | |
779 | } | |
780 | ||
781 | /** | |
782 | * bd_prepare_to_claim - prepare to claim a block device | |
783 | * @bdev: block device of interest | |
784 | * @whole: the whole device containing @bdev, may equal @bdev | |
785 | * @holder: holder trying to claim @bdev | |
786 | * | |
787 | * Prepare to claim @bdev. This function fails if @bdev is already | |
788 | * claimed by another holder and waits if another claiming is in | |
789 | * progress. This function doesn't actually claim. On successful | |
790 | * return, the caller has ownership of bd_claiming and bd_holder[s]. | |
791 | * | |
792 | * CONTEXT: | |
793 | * spin_lock(&bdev_lock). Might release bdev_lock, sleep and regrab | |
794 | * it multiple times. | |
795 | * | |
796 | * RETURNS: | |
797 | * 0 if @bdev can be claimed, -EBUSY otherwise. | |
798 | */ | |
799 | static int bd_prepare_to_claim(struct block_device *bdev, | |
800 | struct block_device *whole, void *holder) | |
801 | { | |
802 | retry: | |
803 | /* if someone else claimed, fail */ | |
804 | if (!bd_may_claim(bdev, whole, holder)) | |
805 | return -EBUSY; | |
806 | ||
807 | /* if claiming is already in progress, wait for it to finish */ | |
808 | if (whole->bd_claiming) { | |
809 | wait_queue_head_t *wq = bit_waitqueue(&whole->bd_claiming, 0); | |
810 | DEFINE_WAIT(wait); | |
811 | ||
812 | prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE); | |
813 | spin_unlock(&bdev_lock); | |
814 | schedule(); | |
815 | finish_wait(wq, &wait); | |
816 | spin_lock(&bdev_lock); | |
817 | goto retry; | |
818 | } | |
819 | ||
820 | /* yay, all mine */ | |
821 | return 0; | |
822 | } | |
823 | ||
824 | /** | |
825 | * bd_start_claiming - start claiming a block device | |
826 | * @bdev: block device of interest | |
827 | * @holder: holder trying to claim @bdev | |
828 | * | |
829 | * @bdev is about to be opened exclusively. Check @bdev can be opened | |
830 | * exclusively and mark that an exclusive open is in progress. Each | |
831 | * successful call to this function must be matched with a call to | |
832 | * either bd_finish_claiming() or bd_abort_claiming() (which do not | |
833 | * fail). | |
834 | * | |
835 | * This function is used to gain exclusive access to the block device | |
836 | * without actually causing other exclusive open attempts to fail. It | |
837 | * should be used when the open sequence itself requires exclusive | |
838 | * access but may subsequently fail. | |
839 | * | |
840 | * CONTEXT: | |
841 | * Might sleep. | |
842 | * | |
843 | * RETURNS: | |
844 | * Pointer to the block device containing @bdev on success, ERR_PTR() | |
845 | * value on failure. | |
846 | */ | |
847 | static struct block_device *bd_start_claiming(struct block_device *bdev, | |
848 | void *holder) | |
849 | { | |
850 | struct gendisk *disk; | |
851 | struct block_device *whole; | |
852 | int partno, err; | |
853 | ||
854 | might_sleep(); | |
855 | ||
856 | /* | |
857 | * @bdev might not have been initialized properly yet, look up | |
858 | * and grab the outer block device the hard way. | |
859 | */ | |
860 | disk = get_gendisk(bdev->bd_dev, &partno); | |
861 | if (!disk) | |
862 | return ERR_PTR(-ENXIO); | |
863 | ||
864 | /* | |
865 | * Normally, @bdev should equal what's returned from bdget_disk() | |
866 | * if partno is 0; however, some drivers (floppy) use multiple | |
867 | * bdev's for the same physical device and @bdev may be one of the | |
868 | * aliases. Keep @bdev if partno is 0. This means claimer | |
869 | * tracking is broken for those devices but it has always been that | |
870 | * way. | |
871 | */ | |
872 | if (partno) | |
873 | whole = bdget_disk(disk, 0); | |
874 | else | |
875 | whole = bdgrab(bdev); | |
876 | ||
877 | module_put(disk->fops->owner); | |
878 | put_disk(disk); | |
879 | if (!whole) | |
880 | return ERR_PTR(-ENOMEM); | |
881 | ||
882 | /* prepare to claim, if successful, mark claiming in progress */ | |
883 | spin_lock(&bdev_lock); | |
884 | ||
885 | err = bd_prepare_to_claim(bdev, whole, holder); | |
886 | if (err == 0) { | |
887 | whole->bd_claiming = holder; | |
888 | spin_unlock(&bdev_lock); | |
889 | return whole; | |
890 | } else { | |
891 | spin_unlock(&bdev_lock); | |
892 | bdput(whole); | |
893 | return ERR_PTR(err); | |
894 | } | |
895 | } | |
896 | ||
897 | #ifdef CONFIG_SYSFS | |
898 | struct bd_holder_disk { | |
899 | struct list_head list; | |
900 | struct gendisk *disk; | |
901 | int refcnt; | |
902 | }; | |
903 | ||
904 | static struct bd_holder_disk *bd_find_holder_disk(struct block_device *bdev, | |
905 | struct gendisk *disk) | |
906 | { | |
907 | struct bd_holder_disk *holder; | |
908 | ||
909 | list_for_each_entry(holder, &bdev->bd_holder_disks, list) | |
910 | if (holder->disk == disk) | |
911 | return holder; | |
912 | return NULL; | |
913 | } | |
914 | ||
915 | static int add_symlink(struct kobject *from, struct kobject *to) | |
916 | { | |
917 | return sysfs_create_link(from, to, kobject_name(to)); | |
918 | } | |
919 | ||
920 | static void del_symlink(struct kobject *from, struct kobject *to) | |
921 | { | |
922 | sysfs_remove_link(from, kobject_name(to)); | |
923 | } | |
924 | ||
925 | /** | |
926 | * bd_link_disk_holder - create symlinks between holding disk and slave bdev | |
927 | * @bdev: the claimed slave bdev | |
928 | * @disk: the holding disk | |
929 | * | |
930 | * DON'T USE THIS UNLESS YOU'RE ALREADY USING IT. | |
931 | * | |
932 | * This functions creates the following sysfs symlinks. | |
933 | * | |
934 | * - from "slaves" directory of the holder @disk to the claimed @bdev | |
935 | * - from "holders" directory of the @bdev to the holder @disk | |
936 | * | |
937 | * For example, if /dev/dm-0 maps to /dev/sda and disk for dm-0 is | |
938 | * passed to bd_link_disk_holder(), then: | |
939 | * | |
940 | * /sys/block/dm-0/slaves/sda --> /sys/block/sda | |
941 | * /sys/block/sda/holders/dm-0 --> /sys/block/dm-0 | |
942 | * | |
943 | * The caller must have claimed @bdev before calling this function and | |
944 | * ensure that both @bdev and @disk are valid during the creation and | |
945 | * lifetime of these symlinks. | |
946 | * | |
947 | * CONTEXT: | |
948 | * Might sleep. | |
949 | * | |
950 | * RETURNS: | |
951 | * 0 on success, -errno on failure. | |
952 | */ | |
953 | int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk) | |
954 | { | |
955 | struct bd_holder_disk *holder; | |
956 | int ret = 0; | |
957 | ||
958 | mutex_lock(&bdev->bd_mutex); | |
959 | ||
960 | WARN_ON_ONCE(!bdev->bd_holder); | |
961 | ||
962 | /* FIXME: remove the following once add_disk() handles errors */ | |
963 | if (WARN_ON(!disk->slave_dir || !bdev->bd_part->holder_dir)) | |
964 | goto out_unlock; | |
965 | ||
966 | holder = bd_find_holder_disk(bdev, disk); | |
967 | if (holder) { | |
968 | holder->refcnt++; | |
969 | goto out_unlock; | |
970 | } | |
971 | ||
972 | holder = kzalloc(sizeof(*holder), GFP_KERNEL); | |
973 | if (!holder) { | |
974 | ret = -ENOMEM; | |
975 | goto out_unlock; | |
976 | } | |
977 | ||
978 | INIT_LIST_HEAD(&holder->list); | |
979 | holder->disk = disk; | |
980 | holder->refcnt = 1; | |
981 | ||
982 | ret = add_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj); | |
983 | if (ret) | |
984 | goto out_free; | |
985 | ||
986 | ret = add_symlink(bdev->bd_part->holder_dir, &disk_to_dev(disk)->kobj); | |
987 | if (ret) | |
988 | goto out_del; | |
989 | /* | |
990 | * bdev could be deleted beneath us which would implicitly destroy | |
991 | * the holder directory. Hold on to it. | |
992 | */ | |
993 | kobject_get(bdev->bd_part->holder_dir); | |
994 | ||
995 | list_add(&holder->list, &bdev->bd_holder_disks); | |
996 | goto out_unlock; | |
997 | ||
998 | out_del: | |
999 | del_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj); | |
1000 | out_free: | |
1001 | kfree(holder); | |
1002 | out_unlock: | |
1003 | mutex_unlock(&bdev->bd_mutex); | |
1004 | return ret; | |
1005 | } | |
1006 | EXPORT_SYMBOL_GPL(bd_link_disk_holder); | |
1007 | ||
1008 | /** | |
1009 | * bd_unlink_disk_holder - destroy symlinks created by bd_link_disk_holder() | |
1010 | * @bdev: the calimed slave bdev | |
1011 | * @disk: the holding disk | |
1012 | * | |
1013 | * DON'T USE THIS UNLESS YOU'RE ALREADY USING IT. | |
1014 | * | |
1015 | * CONTEXT: | |
1016 | * Might sleep. | |
1017 | */ | |
1018 | void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk) | |
1019 | { | |
1020 | struct bd_holder_disk *holder; | |
1021 | ||
1022 | mutex_lock(&bdev->bd_mutex); | |
1023 | ||
1024 | holder = bd_find_holder_disk(bdev, disk); | |
1025 | ||
1026 | if (!WARN_ON_ONCE(holder == NULL) && !--holder->refcnt) { | |
1027 | del_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj); | |
1028 | del_symlink(bdev->bd_part->holder_dir, | |
1029 | &disk_to_dev(disk)->kobj); | |
1030 | kobject_put(bdev->bd_part->holder_dir); | |
1031 | list_del_init(&holder->list); | |
1032 | kfree(holder); | |
1033 | } | |
1034 | ||
1035 | mutex_unlock(&bdev->bd_mutex); | |
1036 | } | |
1037 | EXPORT_SYMBOL_GPL(bd_unlink_disk_holder); | |
1038 | #endif | |
1039 | ||
1040 | /** | |
1041 | * flush_disk - invalidates all buffer-cache entries on a disk | |
1042 | * | |
1043 | * @bdev: struct block device to be flushed | |
1044 | * @kill_dirty: flag to guide handling of dirty inodes | |
1045 | * | |
1046 | * Invalidates all buffer-cache entries on a disk. It should be called | |
1047 | * when a disk has been changed -- either by a media change or online | |
1048 | * resize. | |
1049 | */ | |
1050 | static void flush_disk(struct block_device *bdev, bool kill_dirty) | |
1051 | { | |
1052 | if (__invalidate_device(bdev, kill_dirty)) { | |
1053 | printk(KERN_WARNING "VFS: busy inodes on changed media or " | |
1054 | "resized disk %s\n", | |
1055 | bdev->bd_disk ? bdev->bd_disk->disk_name : ""); | |
1056 | } | |
1057 | ||
1058 | if (!bdev->bd_disk) | |
1059 | return; | |
1060 | if (disk_part_scan_enabled(bdev->bd_disk)) | |
1061 | bdev->bd_invalidated = 1; | |
1062 | } | |
1063 | ||
1064 | /** | |
1065 | * check_disk_size_change - checks for disk size change and adjusts bdev size. | |
1066 | * @disk: struct gendisk to check | |
1067 | * @bdev: struct bdev to adjust. | |
1068 | * | |
1069 | * This routine checks to see if the bdev size does not match the disk size | |
1070 | * and adjusts it if it differs. | |
1071 | */ | |
1072 | void check_disk_size_change(struct gendisk *disk, struct block_device *bdev) | |
1073 | { | |
1074 | loff_t disk_size, bdev_size; | |
1075 | ||
1076 | disk_size = (loff_t)get_capacity(disk) << 9; | |
1077 | bdev_size = i_size_read(bdev->bd_inode); | |
1078 | if (disk_size != bdev_size) { | |
1079 | printk(KERN_INFO | |
1080 | "%s: detected capacity change from %lld to %lld\n", | |
1081 | disk->disk_name, bdev_size, disk_size); | |
1082 | i_size_write(bdev->bd_inode, disk_size); | |
1083 | flush_disk(bdev, false); | |
1084 | } | |
1085 | } | |
1086 | EXPORT_SYMBOL(check_disk_size_change); | |
1087 | ||
1088 | /** | |
1089 | * revalidate_disk - wrapper for lower-level driver's revalidate_disk call-back | |
1090 | * @disk: struct gendisk to be revalidated | |
1091 | * | |
1092 | * This routine is a wrapper for lower-level driver's revalidate_disk | |
1093 | * call-backs. It is used to do common pre and post operations needed | |
1094 | * for all revalidate_disk operations. | |
1095 | */ | |
1096 | int revalidate_disk(struct gendisk *disk) | |
1097 | { | |
1098 | struct block_device *bdev; | |
1099 | int ret = 0; | |
1100 | ||
1101 | if (disk->fops->revalidate_disk) | |
1102 | ret = disk->fops->revalidate_disk(disk); | |
1103 | blk_integrity_revalidate(disk); | |
1104 | bdev = bdget_disk(disk, 0); | |
1105 | if (!bdev) | |
1106 | return ret; | |
1107 | ||
1108 | mutex_lock(&bdev->bd_mutex); | |
1109 | check_disk_size_change(disk, bdev); | |
1110 | bdev->bd_invalidated = 0; | |
1111 | mutex_unlock(&bdev->bd_mutex); | |
1112 | bdput(bdev); | |
1113 | return ret; | |
1114 | } | |
1115 | EXPORT_SYMBOL(revalidate_disk); | |
1116 | ||
1117 | /* | |
1118 | * This routine checks whether a removable media has been changed, | |
1119 | * and invalidates all buffer-cache-entries in that case. This | |
1120 | * is a relatively slow routine, so we have to try to minimize using | |
1121 | * it. Thus it is called only upon a 'mount' or 'open'. This | |
1122 | * is the best way of combining speed and utility, I think. | |
1123 | * People changing diskettes in the middle of an operation deserve | |
1124 | * to lose :-) | |
1125 | */ | |
1126 | int check_disk_change(struct block_device *bdev) | |
1127 | { | |
1128 | struct gendisk *disk = bdev->bd_disk; | |
1129 | const struct block_device_operations *bdops = disk->fops; | |
1130 | unsigned int events; | |
1131 | ||
1132 | events = disk_clear_events(disk, DISK_EVENT_MEDIA_CHANGE | | |
1133 | DISK_EVENT_EJECT_REQUEST); | |
1134 | if (!(events & DISK_EVENT_MEDIA_CHANGE)) | |
1135 | return 0; | |
1136 | ||
1137 | flush_disk(bdev, true); | |
1138 | if (bdops->revalidate_disk) | |
1139 | bdops->revalidate_disk(bdev->bd_disk); | |
1140 | return 1; | |
1141 | } | |
1142 | ||
1143 | EXPORT_SYMBOL(check_disk_change); | |
1144 | ||
1145 | void bd_set_size(struct block_device *bdev, loff_t size) | |
1146 | { | |
1147 | unsigned bsize = bdev_logical_block_size(bdev); | |
1148 | ||
1149 | inode_lock(bdev->bd_inode); | |
1150 | i_size_write(bdev->bd_inode, size); | |
1151 | inode_unlock(bdev->bd_inode); | |
1152 | while (bsize < PAGE_SIZE) { | |
1153 | if (size & bsize) | |
1154 | break; | |
1155 | bsize <<= 1; | |
1156 | } | |
1157 | bdev->bd_block_size = bsize; | |
1158 | bdev->bd_inode->i_blkbits = blksize_bits(bsize); | |
1159 | } | |
1160 | EXPORT_SYMBOL(bd_set_size); | |
1161 | ||
1162 | static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part); | |
1163 | ||
1164 | /* | |
1165 | * bd_mutex locking: | |
1166 | * | |
1167 | * mutex_lock(part->bd_mutex) | |
1168 | * mutex_lock_nested(whole->bd_mutex, 1) | |
1169 | */ | |
1170 | ||
1171 | static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part) | |
1172 | { | |
1173 | struct gendisk *disk; | |
1174 | struct module *owner; | |
1175 | int ret; | |
1176 | int partno; | |
1177 | int perm = 0; | |
1178 | ||
1179 | if (mode & FMODE_READ) | |
1180 | perm |= MAY_READ; | |
1181 | if (mode & FMODE_WRITE) | |
1182 | perm |= MAY_WRITE; | |
1183 | /* | |
1184 | * hooks: /n/, see "layering violations". | |
1185 | */ | |
1186 | if (!for_part) { | |
1187 | ret = devcgroup_inode_permission(bdev->bd_inode, perm); | |
1188 | if (ret != 0) { | |
1189 | bdput(bdev); | |
1190 | return ret; | |
1191 | } | |
1192 | } | |
1193 | ||
1194 | restart: | |
1195 | ||
1196 | ret = -ENXIO; | |
1197 | disk = get_gendisk(bdev->bd_dev, &partno); | |
1198 | if (!disk) | |
1199 | goto out; | |
1200 | owner = disk->fops->owner; | |
1201 | ||
1202 | disk_block_events(disk); | |
1203 | mutex_lock_nested(&bdev->bd_mutex, for_part); | |
1204 | if (!bdev->bd_openers) { | |
1205 | bdev->bd_disk = disk; | |
1206 | bdev->bd_queue = disk->queue; | |
1207 | bdev->bd_contains = bdev; | |
1208 | if (IS_ENABLED(CONFIG_BLK_DEV_DAX) && disk->fops->direct_access) | |
1209 | bdev->bd_inode->i_flags = S_DAX; | |
1210 | else | |
1211 | bdev->bd_inode->i_flags = 0; | |
1212 | ||
1213 | if (!partno) { | |
1214 | ret = -ENXIO; | |
1215 | bdev->bd_part = disk_get_part(disk, partno); | |
1216 | if (!bdev->bd_part) | |
1217 | goto out_clear; | |
1218 | ||
1219 | ret = 0; | |
1220 | if (disk->fops->open) { | |
1221 | ret = disk->fops->open(bdev, mode); | |
1222 | if (ret == -ERESTARTSYS) { | |
1223 | /* Lost a race with 'disk' being | |
1224 | * deleted, try again. | |
1225 | * See md.c | |
1226 | */ | |
1227 | disk_put_part(bdev->bd_part); | |
1228 | bdev->bd_part = NULL; | |
1229 | bdev->bd_disk = NULL; | |
1230 | bdev->bd_queue = NULL; | |
1231 | mutex_unlock(&bdev->bd_mutex); | |
1232 | disk_unblock_events(disk); | |
1233 | put_disk(disk); | |
1234 | module_put(owner); | |
1235 | goto restart; | |
1236 | } | |
1237 | } | |
1238 | ||
1239 | if (!ret) { | |
1240 | bd_set_size(bdev,(loff_t)get_capacity(disk)<<9); | |
1241 | if (!blkdev_dax_capable(bdev)) | |
1242 | bdev->bd_inode->i_flags &= ~S_DAX; | |
1243 | } | |
1244 | ||
1245 | /* | |
1246 | * If the device is invalidated, rescan partition | |
1247 | * if open succeeded or failed with -ENOMEDIUM. | |
1248 | * The latter is necessary to prevent ghost | |
1249 | * partitions on a removed medium. | |
1250 | */ | |
1251 | if (bdev->bd_invalidated) { | |
1252 | if (!ret) | |
1253 | rescan_partitions(disk, bdev); | |
1254 | else if (ret == -ENOMEDIUM) | |
1255 | invalidate_partitions(disk, bdev); | |
1256 | } | |
1257 | ||
1258 | if (ret) | |
1259 | goto out_clear; | |
1260 | } else { | |
1261 | struct block_device *whole; | |
1262 | whole = bdget_disk(disk, 0); | |
1263 | ret = -ENOMEM; | |
1264 | if (!whole) | |
1265 | goto out_clear; | |
1266 | BUG_ON(for_part); | |
1267 | ret = __blkdev_get(whole, mode, 1); | |
1268 | if (ret) | |
1269 | goto out_clear; | |
1270 | bdev->bd_contains = whole; | |
1271 | bdev->bd_part = disk_get_part(disk, partno); | |
1272 | if (!(disk->flags & GENHD_FL_UP) || | |
1273 | !bdev->bd_part || !bdev->bd_part->nr_sects) { | |
1274 | ret = -ENXIO; | |
1275 | goto out_clear; | |
1276 | } | |
1277 | bd_set_size(bdev, (loff_t)bdev->bd_part->nr_sects << 9); | |
1278 | if (!blkdev_dax_capable(bdev)) | |
1279 | bdev->bd_inode->i_flags &= ~S_DAX; | |
1280 | } | |
1281 | } else { | |
1282 | if (bdev->bd_contains == bdev) { | |
1283 | ret = 0; | |
1284 | if (bdev->bd_disk->fops->open) | |
1285 | ret = bdev->bd_disk->fops->open(bdev, mode); | |
1286 | /* the same as first opener case, read comment there */ | |
1287 | if (bdev->bd_invalidated) { | |
1288 | if (!ret) | |
1289 | rescan_partitions(bdev->bd_disk, bdev); | |
1290 | else if (ret == -ENOMEDIUM) | |
1291 | invalidate_partitions(bdev->bd_disk, bdev); | |
1292 | } | |
1293 | if (ret) | |
1294 | goto out_unlock_bdev; | |
1295 | } | |
1296 | /* only one opener holds refs to the module and disk */ | |
1297 | put_disk(disk); | |
1298 | module_put(owner); | |
1299 | } | |
1300 | bdev->bd_openers++; | |
1301 | if (for_part) | |
1302 | bdev->bd_part_count++; | |
1303 | mutex_unlock(&bdev->bd_mutex); | |
1304 | disk_unblock_events(disk); | |
1305 | return 0; | |
1306 | ||
1307 | out_clear: | |
1308 | disk_put_part(bdev->bd_part); | |
1309 | bdev->bd_disk = NULL; | |
1310 | bdev->bd_part = NULL; | |
1311 | bdev->bd_queue = NULL; | |
1312 | if (bdev != bdev->bd_contains) | |
1313 | __blkdev_put(bdev->bd_contains, mode, 1); | |
1314 | bdev->bd_contains = NULL; | |
1315 | out_unlock_bdev: | |
1316 | mutex_unlock(&bdev->bd_mutex); | |
1317 | disk_unblock_events(disk); | |
1318 | put_disk(disk); | |
1319 | module_put(owner); | |
1320 | out: | |
1321 | bdput(bdev); | |
1322 | ||
1323 | return ret; | |
1324 | } | |
1325 | ||
1326 | /** | |
1327 | * blkdev_get - open a block device | |
1328 | * @bdev: block_device to open | |
1329 | * @mode: FMODE_* mask | |
1330 | * @holder: exclusive holder identifier | |
1331 | * | |
1332 | * Open @bdev with @mode. If @mode includes %FMODE_EXCL, @bdev is | |
1333 | * open with exclusive access. Specifying %FMODE_EXCL with %NULL | |
1334 | * @holder is invalid. Exclusive opens may nest for the same @holder. | |
1335 | * | |
1336 | * On success, the reference count of @bdev is unchanged. On failure, | |
1337 | * @bdev is put. | |
1338 | * | |
1339 | * CONTEXT: | |
1340 | * Might sleep. | |
1341 | * | |
1342 | * RETURNS: | |
1343 | * 0 on success, -errno on failure. | |
1344 | */ | |
1345 | int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder) | |
1346 | { | |
1347 | struct block_device *whole = NULL; | |
1348 | int res; | |
1349 | ||
1350 | WARN_ON_ONCE((mode & FMODE_EXCL) && !holder); | |
1351 | ||
1352 | if ((mode & FMODE_EXCL) && holder) { | |
1353 | whole = bd_start_claiming(bdev, holder); | |
1354 | if (IS_ERR(whole)) { | |
1355 | bdput(bdev); | |
1356 | return PTR_ERR(whole); | |
1357 | } | |
1358 | } | |
1359 | ||
1360 | res = __blkdev_get(bdev, mode, 0); | |
1361 | ||
1362 | if (whole) { | |
1363 | struct gendisk *disk = whole->bd_disk; | |
1364 | ||
1365 | /* finish claiming */ | |
1366 | mutex_lock(&bdev->bd_mutex); | |
1367 | spin_lock(&bdev_lock); | |
1368 | ||
1369 | if (!res) { | |
1370 | BUG_ON(!bd_may_claim(bdev, whole, holder)); | |
1371 | /* | |
1372 | * Note that for a whole device bd_holders | |
1373 | * will be incremented twice, and bd_holder | |
1374 | * will be set to bd_may_claim before being | |
1375 | * set to holder | |
1376 | */ | |
1377 | whole->bd_holders++; | |
1378 | whole->bd_holder = bd_may_claim; | |
1379 | bdev->bd_holders++; | |
1380 | bdev->bd_holder = holder; | |
1381 | } | |
1382 | ||
1383 | /* tell others that we're done */ | |
1384 | BUG_ON(whole->bd_claiming != holder); | |
1385 | whole->bd_claiming = NULL; | |
1386 | wake_up_bit(&whole->bd_claiming, 0); | |
1387 | ||
1388 | spin_unlock(&bdev_lock); | |
1389 | ||
1390 | /* | |
1391 | * Block event polling for write claims if requested. Any | |
1392 | * write holder makes the write_holder state stick until | |
1393 | * all are released. This is good enough and tracking | |
1394 | * individual writeable reference is too fragile given the | |
1395 | * way @mode is used in blkdev_get/put(). | |
1396 | */ | |
1397 | if (!res && (mode & FMODE_WRITE) && !bdev->bd_write_holder && | |
1398 | (disk->flags & GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE)) { | |
1399 | bdev->bd_write_holder = true; | |
1400 | disk_block_events(disk); | |
1401 | } | |
1402 | ||
1403 | mutex_unlock(&bdev->bd_mutex); | |
1404 | bdput(whole); | |
1405 | } | |
1406 | ||
1407 | return res; | |
1408 | } | |
1409 | EXPORT_SYMBOL(blkdev_get); | |
1410 | ||
1411 | /** | |
1412 | * blkdev_get_by_path - open a block device by name | |
1413 | * @path: path to the block device to open | |
1414 | * @mode: FMODE_* mask | |
1415 | * @holder: exclusive holder identifier | |
1416 | * | |
1417 | * Open the blockdevice described by the device file at @path. @mode | |
1418 | * and @holder are identical to blkdev_get(). | |
1419 | * | |
1420 | * On success, the returned block_device has reference count of one. | |
1421 | * | |
1422 | * CONTEXT: | |
1423 | * Might sleep. | |
1424 | * | |
1425 | * RETURNS: | |
1426 | * Pointer to block_device on success, ERR_PTR(-errno) on failure. | |
1427 | */ | |
1428 | struct block_device *blkdev_get_by_path(const char *path, fmode_t mode, | |
1429 | void *holder) | |
1430 | { | |
1431 | struct block_device *bdev; | |
1432 | int err; | |
1433 | ||
1434 | bdev = lookup_bdev(path); | |
1435 | if (IS_ERR(bdev)) | |
1436 | return bdev; | |
1437 | ||
1438 | err = blkdev_get(bdev, mode, holder); | |
1439 | if (err) | |
1440 | return ERR_PTR(err); | |
1441 | ||
1442 | if ((mode & FMODE_WRITE) && bdev_read_only(bdev)) { | |
1443 | blkdev_put(bdev, mode); | |
1444 | return ERR_PTR(-EACCES); | |
1445 | } | |
1446 | ||
1447 | return bdev; | |
1448 | } | |
1449 | EXPORT_SYMBOL(blkdev_get_by_path); | |
1450 | ||
1451 | /** | |
1452 | * blkdev_get_by_dev - open a block device by device number | |
1453 | * @dev: device number of block device to open | |
1454 | * @mode: FMODE_* mask | |
1455 | * @holder: exclusive holder identifier | |
1456 | * | |
1457 | * Open the blockdevice described by device number @dev. @mode and | |
1458 | * @holder are identical to blkdev_get(). | |
1459 | * | |
1460 | * Use it ONLY if you really do not have anything better - i.e. when | |
1461 | * you are behind a truly sucky interface and all you are given is a | |
1462 | * device number. _Never_ to be used for internal purposes. If you | |
1463 | * ever need it - reconsider your API. | |
1464 | * | |
1465 | * On success, the returned block_device has reference count of one. | |
1466 | * | |
1467 | * CONTEXT: | |
1468 | * Might sleep. | |
1469 | * | |
1470 | * RETURNS: | |
1471 | * Pointer to block_device on success, ERR_PTR(-errno) on failure. | |
1472 | */ | |
1473 | struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder) | |
1474 | { | |
1475 | struct block_device *bdev; | |
1476 | int err; | |
1477 | ||
1478 | bdev = bdget(dev); | |
1479 | if (!bdev) | |
1480 | return ERR_PTR(-ENOMEM); | |
1481 | ||
1482 | err = blkdev_get(bdev, mode, holder); | |
1483 | if (err) | |
1484 | return ERR_PTR(err); | |
1485 | ||
1486 | return bdev; | |
1487 | } | |
1488 | EXPORT_SYMBOL(blkdev_get_by_dev); | |
1489 | ||
1490 | static int blkdev_open(struct inode * inode, struct file * filp) | |
1491 | { | |
1492 | struct block_device *bdev; | |
1493 | ||
1494 | /* | |
1495 | * Preserve backwards compatibility and allow large file access | |
1496 | * even if userspace doesn't ask for it explicitly. Some mkfs | |
1497 | * binary needs it. We might want to drop this workaround | |
1498 | * during an unstable branch. | |
1499 | */ | |
1500 | filp->f_flags |= O_LARGEFILE; | |
1501 | ||
1502 | if (filp->f_flags & O_NDELAY) | |
1503 | filp->f_mode |= FMODE_NDELAY; | |
1504 | if (filp->f_flags & O_EXCL) | |
1505 | filp->f_mode |= FMODE_EXCL; | |
1506 | if ((filp->f_flags & O_ACCMODE) == 3) | |
1507 | filp->f_mode |= FMODE_WRITE_IOCTL; | |
1508 | ||
1509 | bdev = bd_acquire(inode); | |
1510 | if (bdev == NULL) | |
1511 | return -ENOMEM; | |
1512 | ||
1513 | filp->f_mapping = bdev->bd_inode->i_mapping; | |
1514 | ||
1515 | return blkdev_get(bdev, filp->f_mode, filp); | |
1516 | } | |
1517 | ||
1518 | static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part) | |
1519 | { | |
1520 | struct gendisk *disk = bdev->bd_disk; | |
1521 | struct block_device *victim = NULL; | |
1522 | ||
1523 | mutex_lock_nested(&bdev->bd_mutex, for_part); | |
1524 | if (for_part) | |
1525 | bdev->bd_part_count--; | |
1526 | ||
1527 | if (!--bdev->bd_openers) { | |
1528 | WARN_ON_ONCE(bdev->bd_holders); | |
1529 | sync_blockdev(bdev); | |
1530 | kill_bdev(bdev); | |
1531 | ||
1532 | bdev_write_inode(bdev); | |
1533 | /* | |
1534 | * Detaching bdev inode from its wb in __destroy_inode() | |
1535 | * is too late: the queue which embeds its bdi (along with | |
1536 | * root wb) can be gone as soon as we put_disk() below. | |
1537 | */ | |
1538 | inode_detach_wb(bdev->bd_inode); | |
1539 | } | |
1540 | if (bdev->bd_contains == bdev) { | |
1541 | if (disk->fops->release) | |
1542 | disk->fops->release(disk, mode); | |
1543 | } | |
1544 | if (!bdev->bd_openers) { | |
1545 | struct module *owner = disk->fops->owner; | |
1546 | ||
1547 | disk_put_part(bdev->bd_part); | |
1548 | bdev->bd_part = NULL; | |
1549 | bdev->bd_disk = NULL; | |
1550 | if (bdev != bdev->bd_contains) | |
1551 | victim = bdev->bd_contains; | |
1552 | bdev->bd_contains = NULL; | |
1553 | ||
1554 | put_disk(disk); | |
1555 | module_put(owner); | |
1556 | } | |
1557 | mutex_unlock(&bdev->bd_mutex); | |
1558 | bdput(bdev); | |
1559 | if (victim) | |
1560 | __blkdev_put(victim, mode, 1); | |
1561 | } | |
1562 | ||
1563 | void blkdev_put(struct block_device *bdev, fmode_t mode) | |
1564 | { | |
1565 | mutex_lock(&bdev->bd_mutex); | |
1566 | ||
1567 | if (mode & FMODE_EXCL) { | |
1568 | bool bdev_free; | |
1569 | ||
1570 | /* | |
1571 | * Release a claim on the device. The holder fields | |
1572 | * are protected with bdev_lock. bd_mutex is to | |
1573 | * synchronize disk_holder unlinking. | |
1574 | */ | |
1575 | spin_lock(&bdev_lock); | |
1576 | ||
1577 | WARN_ON_ONCE(--bdev->bd_holders < 0); | |
1578 | WARN_ON_ONCE(--bdev->bd_contains->bd_holders < 0); | |
1579 | ||
1580 | /* bd_contains might point to self, check in a separate step */ | |
1581 | if ((bdev_free = !bdev->bd_holders)) | |
1582 | bdev->bd_holder = NULL; | |
1583 | if (!bdev->bd_contains->bd_holders) | |
1584 | bdev->bd_contains->bd_holder = NULL; | |
1585 | ||
1586 | spin_unlock(&bdev_lock); | |
1587 | ||
1588 | /* | |
1589 | * If this was the last claim, remove holder link and | |
1590 | * unblock evpoll if it was a write holder. | |
1591 | */ | |
1592 | if (bdev_free && bdev->bd_write_holder) { | |
1593 | disk_unblock_events(bdev->bd_disk); | |
1594 | bdev->bd_write_holder = false; | |
1595 | } | |
1596 | } | |
1597 | ||
1598 | /* | |
1599 | * Trigger event checking and tell drivers to flush MEDIA_CHANGE | |
1600 | * event. This is to ensure detection of media removal commanded | |
1601 | * from userland - e.g. eject(1). | |
1602 | */ | |
1603 | disk_flush_events(bdev->bd_disk, DISK_EVENT_MEDIA_CHANGE); | |
1604 | ||
1605 | mutex_unlock(&bdev->bd_mutex); | |
1606 | ||
1607 | __blkdev_put(bdev, mode, 0); | |
1608 | } | |
1609 | EXPORT_SYMBOL(blkdev_put); | |
1610 | ||
1611 | static int blkdev_close(struct inode * inode, struct file * filp) | |
1612 | { | |
1613 | struct block_device *bdev = I_BDEV(bdev_file_inode(filp)); | |
1614 | blkdev_put(bdev, filp->f_mode); | |
1615 | return 0; | |
1616 | } | |
1617 | ||
1618 | static long block_ioctl(struct file *file, unsigned cmd, unsigned long arg) | |
1619 | { | |
1620 | struct block_device *bdev = I_BDEV(bdev_file_inode(file)); | |
1621 | fmode_t mode = file->f_mode; | |
1622 | ||
1623 | /* | |
1624 | * O_NDELAY can be altered using fcntl(.., F_SETFL, ..), so we have | |
1625 | * to updated it before every ioctl. | |
1626 | */ | |
1627 | if (file->f_flags & O_NDELAY) | |
1628 | mode |= FMODE_NDELAY; | |
1629 | else | |
1630 | mode &= ~FMODE_NDELAY; | |
1631 | ||
1632 | return blkdev_ioctl(bdev, mode, cmd, arg); | |
1633 | } | |
1634 | ||
1635 | /* | |
1636 | * Write data to the block device. Only intended for the block device itself | |
1637 | * and the raw driver which basically is a fake block device. | |
1638 | * | |
1639 | * Does not take i_mutex for the write and thus is not for general purpose | |
1640 | * use. | |
1641 | */ | |
1642 | ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from) | |
1643 | { | |
1644 | struct file *file = iocb->ki_filp; | |
1645 | struct inode *bd_inode = bdev_file_inode(file); | |
1646 | loff_t size = i_size_read(bd_inode); | |
1647 | struct blk_plug plug; | |
1648 | ssize_t ret; | |
1649 | ||
1650 | if (bdev_read_only(I_BDEV(bd_inode))) | |
1651 | return -EPERM; | |
1652 | ||
1653 | if (!iov_iter_count(from)) | |
1654 | return 0; | |
1655 | ||
1656 | if (iocb->ki_pos >= size) | |
1657 | return -ENOSPC; | |
1658 | ||
1659 | iov_iter_truncate(from, size - iocb->ki_pos); | |
1660 | ||
1661 | blk_start_plug(&plug); | |
1662 | ret = __generic_file_write_iter(iocb, from); | |
1663 | if (ret > 0) { | |
1664 | ssize_t err; | |
1665 | err = generic_write_sync(file, iocb->ki_pos - ret, ret); | |
1666 | if (err < 0) | |
1667 | ret = err; | |
1668 | } | |
1669 | blk_finish_plug(&plug); | |
1670 | return ret; | |
1671 | } | |
1672 | EXPORT_SYMBOL_GPL(blkdev_write_iter); | |
1673 | ||
1674 | ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to) | |
1675 | { | |
1676 | struct file *file = iocb->ki_filp; | |
1677 | struct inode *bd_inode = bdev_file_inode(file); | |
1678 | loff_t size = i_size_read(bd_inode); | |
1679 | loff_t pos = iocb->ki_pos; | |
1680 | ||
1681 | if (pos >= size) | |
1682 | return 0; | |
1683 | ||
1684 | size -= pos; | |
1685 | iov_iter_truncate(to, size); | |
1686 | return generic_file_read_iter(iocb, to); | |
1687 | } | |
1688 | EXPORT_SYMBOL_GPL(blkdev_read_iter); | |
1689 | ||
1690 | /* | |
1691 | * Try to release a page associated with block device when the system | |
1692 | * is under memory pressure. | |
1693 | */ | |
1694 | static int blkdev_releasepage(struct page *page, gfp_t wait) | |
1695 | { | |
1696 | struct super_block *super = BDEV_I(page->mapping->host)->bdev.bd_super; | |
1697 | ||
1698 | if (super && super->s_op->bdev_try_to_free_page) | |
1699 | return super->s_op->bdev_try_to_free_page(super, page, wait); | |
1700 | ||
1701 | return try_to_free_buffers(page); | |
1702 | } | |
1703 | ||
1704 | static int blkdev_writepages(struct address_space *mapping, | |
1705 | struct writeback_control *wbc) | |
1706 | { | |
1707 | if (dax_mapping(mapping)) { | |
1708 | struct block_device *bdev = I_BDEV(mapping->host); | |
1709 | ||
1710 | return dax_writeback_mapping_range(mapping, bdev, wbc); | |
1711 | } | |
1712 | return generic_writepages(mapping, wbc); | |
1713 | } | |
1714 | ||
1715 | static const struct address_space_operations def_blk_aops = { | |
1716 | .readpage = blkdev_readpage, | |
1717 | .readpages = blkdev_readpages, | |
1718 | .writepage = blkdev_writepage, | |
1719 | .write_begin = blkdev_write_begin, | |
1720 | .write_end = blkdev_write_end, | |
1721 | .writepages = blkdev_writepages, | |
1722 | .releasepage = blkdev_releasepage, | |
1723 | .direct_IO = blkdev_direct_IO, | |
1724 | .is_dirty_writeback = buffer_check_dirty_writeback, | |
1725 | }; | |
1726 | ||
1727 | #ifdef CONFIG_FS_DAX | |
1728 | /* | |
1729 | * In the raw block case we do not need to contend with truncation nor | |
1730 | * unwritten file extents. Without those concerns there is no need for | |
1731 | * additional locking beyond the mmap_sem context that these routines | |
1732 | * are already executing under. | |
1733 | * | |
1734 | * Note, there is no protection if the block device is dynamically | |
1735 | * resized (partition grow/shrink) during a fault. A stable block device | |
1736 | * size is already not enforced in the blkdev_direct_IO path. | |
1737 | * | |
1738 | * For DAX, it is the responsibility of the block device driver to | |
1739 | * ensure the whole-disk device size is stable while requests are in | |
1740 | * flight. | |
1741 | * | |
1742 | * Finally, unlike the filemap_page_mkwrite() case there is no | |
1743 | * filesystem superblock to sync against freezing. We still include a | |
1744 | * pfn_mkwrite callback for dax drivers to receive write fault | |
1745 | * notifications. | |
1746 | */ | |
1747 | static int blkdev_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf) | |
1748 | { | |
1749 | return __dax_fault(vma, vmf, blkdev_get_block); | |
1750 | } | |
1751 | ||
1752 | static int blkdev_dax_pfn_mkwrite(struct vm_area_struct *vma, | |
1753 | struct vm_fault *vmf) | |
1754 | { | |
1755 | return dax_pfn_mkwrite(vma, vmf); | |
1756 | } | |
1757 | ||
1758 | static int blkdev_dax_pmd_fault(struct vm_area_struct *vma, unsigned long addr, | |
1759 | pmd_t *pmd, unsigned int flags) | |
1760 | { | |
1761 | return __dax_pmd_fault(vma, addr, pmd, flags, blkdev_get_block); | |
1762 | } | |
1763 | ||
1764 | static const struct vm_operations_struct blkdev_dax_vm_ops = { | |
1765 | .fault = blkdev_dax_fault, | |
1766 | .pmd_fault = blkdev_dax_pmd_fault, | |
1767 | .pfn_mkwrite = blkdev_dax_pfn_mkwrite, | |
1768 | }; | |
1769 | ||
1770 | static const struct vm_operations_struct blkdev_default_vm_ops = { | |
1771 | .fault = filemap_fault, | |
1772 | .map_pages = filemap_map_pages, | |
1773 | }; | |
1774 | ||
1775 | static int blkdev_mmap(struct file *file, struct vm_area_struct *vma) | |
1776 | { | |
1777 | struct inode *bd_inode = bdev_file_inode(file); | |
1778 | ||
1779 | file_accessed(file); | |
1780 | if (IS_DAX(bd_inode)) { | |
1781 | vma->vm_ops = &blkdev_dax_vm_ops; | |
1782 | vma->vm_flags |= VM_MIXEDMAP | VM_HUGEPAGE; | |
1783 | } else { | |
1784 | vma->vm_ops = &blkdev_default_vm_ops; | |
1785 | } | |
1786 | ||
1787 | return 0; | |
1788 | } | |
1789 | #else | |
1790 | #define blkdev_mmap generic_file_mmap | |
1791 | #endif | |
1792 | ||
1793 | const struct file_operations def_blk_fops = { | |
1794 | .open = blkdev_open, | |
1795 | .release = blkdev_close, | |
1796 | .llseek = block_llseek, | |
1797 | .read_iter = blkdev_read_iter, | |
1798 | .write_iter = blkdev_write_iter, | |
1799 | .mmap = blkdev_mmap, | |
1800 | .fsync = blkdev_fsync, | |
1801 | .unlocked_ioctl = block_ioctl, | |
1802 | #ifdef CONFIG_COMPAT | |
1803 | .compat_ioctl = compat_blkdev_ioctl, | |
1804 | #endif | |
1805 | .splice_read = generic_file_splice_read, | |
1806 | .splice_write = iter_file_splice_write, | |
1807 | }; | |
1808 | ||
1809 | int ioctl_by_bdev(struct block_device *bdev, unsigned cmd, unsigned long arg) | |
1810 | { | |
1811 | int res; | |
1812 | mm_segment_t old_fs = get_fs(); | |
1813 | set_fs(KERNEL_DS); | |
1814 | res = blkdev_ioctl(bdev, 0, cmd, arg); | |
1815 | set_fs(old_fs); | |
1816 | return res; | |
1817 | } | |
1818 | ||
1819 | EXPORT_SYMBOL(ioctl_by_bdev); | |
1820 | ||
1821 | /** | |
1822 | * lookup_bdev - lookup a struct block_device by name | |
1823 | * @pathname: special file representing the block device | |
1824 | * | |
1825 | * Get a reference to the blockdevice at @pathname in the current | |
1826 | * namespace if possible and return it. Return ERR_PTR(error) | |
1827 | * otherwise. | |
1828 | */ | |
1829 | struct block_device *lookup_bdev(const char *pathname) | |
1830 | { | |
1831 | struct block_device *bdev; | |
1832 | struct inode *inode; | |
1833 | struct path path; | |
1834 | int error; | |
1835 | ||
1836 | if (!pathname || !*pathname) | |
1837 | return ERR_PTR(-EINVAL); | |
1838 | ||
1839 | error = kern_path(pathname, LOOKUP_FOLLOW, &path); | |
1840 | if (error) | |
1841 | return ERR_PTR(error); | |
1842 | ||
1843 | inode = d_backing_inode(path.dentry); | |
1844 | error = -ENOTBLK; | |
1845 | if (!S_ISBLK(inode->i_mode)) | |
1846 | goto fail; | |
1847 | error = -EACCES; | |
1848 | if (path.mnt->mnt_flags & MNT_NODEV) | |
1849 | goto fail; | |
1850 | error = -ENOMEM; | |
1851 | bdev = bd_acquire(inode); | |
1852 | if (!bdev) | |
1853 | goto fail; | |
1854 | out: | |
1855 | path_put(&path); | |
1856 | return bdev; | |
1857 | fail: | |
1858 | bdev = ERR_PTR(error); | |
1859 | goto out; | |
1860 | } | |
1861 | EXPORT_SYMBOL(lookup_bdev); | |
1862 | ||
1863 | int __invalidate_device(struct block_device *bdev, bool kill_dirty) | |
1864 | { | |
1865 | struct super_block *sb = get_super(bdev); | |
1866 | int res = 0; | |
1867 | ||
1868 | if (sb) { | |
1869 | /* | |
1870 | * no need to lock the super, get_super holds the | |
1871 | * read mutex so the filesystem cannot go away | |
1872 | * under us (->put_super runs with the write lock | |
1873 | * hold). | |
1874 | */ | |
1875 | shrink_dcache_sb(sb); | |
1876 | res = invalidate_inodes(sb, kill_dirty); | |
1877 | drop_super(sb); | |
1878 | } | |
1879 | invalidate_bdev(bdev); | |
1880 | return res; | |
1881 | } | |
1882 | EXPORT_SYMBOL(__invalidate_device); | |
1883 | ||
1884 | void iterate_bdevs(void (*func)(struct block_device *, void *), void *arg) | |
1885 | { | |
1886 | struct inode *inode, *old_inode = NULL; | |
1887 | ||
1888 | spin_lock(&blockdev_superblock->s_inode_list_lock); | |
1889 | list_for_each_entry(inode, &blockdev_superblock->s_inodes, i_sb_list) { | |
1890 | struct address_space *mapping = inode->i_mapping; | |
1891 | ||
1892 | spin_lock(&inode->i_lock); | |
1893 | if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW) || | |
1894 | mapping->nrpages == 0) { | |
1895 | spin_unlock(&inode->i_lock); | |
1896 | continue; | |
1897 | } | |
1898 | __iget(inode); | |
1899 | spin_unlock(&inode->i_lock); | |
1900 | spin_unlock(&blockdev_superblock->s_inode_list_lock); | |
1901 | /* | |
1902 | * We hold a reference to 'inode' so it couldn't have been | |
1903 | * removed from s_inodes list while we dropped the | |
1904 | * s_inode_list_lock We cannot iput the inode now as we can | |
1905 | * be holding the last reference and we cannot iput it under | |
1906 | * s_inode_list_lock. So we keep the reference and iput it | |
1907 | * later. | |
1908 | */ | |
1909 | iput(old_inode); | |
1910 | old_inode = inode; | |
1911 | ||
1912 | func(I_BDEV(inode), arg); | |
1913 | ||
1914 | spin_lock(&blockdev_superblock->s_inode_list_lock); | |
1915 | } | |
1916 | spin_unlock(&blockdev_superblock->s_inode_list_lock); | |
1917 | iput(old_inode); | |
1918 | } |