4 * Copyright (C) 1991, 1992 Linus Torvalds
5 * Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE
8 #include <linux/init.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 <asm/uaccess.h>
35 struct block_device bdev
;
36 struct inode vfs_inode
;
39 static const struct address_space_operations def_blk_aops
;
41 static inline struct bdev_inode
*BDEV_I(struct inode
*inode
)
43 return container_of(inode
, struct bdev_inode
, vfs_inode
);
46 struct block_device
*I_BDEV(struct inode
*inode
)
48 return &BDEV_I(inode
)->bdev
;
50 EXPORT_SYMBOL(I_BDEV
);
52 static void bdev_write_inode(struct inode
*inode
)
54 spin_lock(&inode
->i_lock
);
55 while (inode
->i_state
& I_DIRTY
) {
56 spin_unlock(&inode
->i_lock
);
57 WARN_ON_ONCE(write_inode_now(inode
, true));
58 spin_lock(&inode
->i_lock
);
60 spin_unlock(&inode
->i_lock
);
63 /* Kill _all_ buffers and pagecache , dirty or not.. */
64 void kill_bdev(struct block_device
*bdev
)
66 struct address_space
*mapping
= bdev
->bd_inode
->i_mapping
;
68 if (mapping
->nrpages
== 0 && mapping
->nrshadows
== 0)
72 truncate_inode_pages(mapping
, 0);
74 EXPORT_SYMBOL(kill_bdev
);
76 /* Invalidate clean unused buffers and pagecache. */
77 void invalidate_bdev(struct block_device
*bdev
)
79 struct address_space
*mapping
= bdev
->bd_inode
->i_mapping
;
81 if (mapping
->nrpages
== 0)
85 lru_add_drain_all(); /* make sure all lru add caches are flushed */
86 invalidate_mapping_pages(mapping
, 0, -1);
87 /* 99% of the time, we don't need to flush the cleancache on the bdev.
88 * But, for the strange corners, lets be cautious
90 cleancache_invalidate_inode(mapping
);
92 EXPORT_SYMBOL(invalidate_bdev
);
94 int set_blocksize(struct block_device
*bdev
, int size
)
96 /* Size must be a power of two, and between 512 and PAGE_SIZE */
97 if (size
> PAGE_SIZE
|| size
< 512 || !is_power_of_2(size
))
100 /* Size cannot be smaller than the size supported by the device */
101 if (size
< bdev_logical_block_size(bdev
))
104 /* Don't change the size if it is same as current */
105 if (bdev
->bd_block_size
!= size
) {
107 bdev
->bd_block_size
= size
;
108 bdev
->bd_inode
->i_blkbits
= blksize_bits(size
);
114 EXPORT_SYMBOL(set_blocksize
);
116 int sb_set_blocksize(struct super_block
*sb
, int size
)
118 if (set_blocksize(sb
->s_bdev
, size
))
120 /* If we get here, we know size is power of two
121 * and it's value is between 512 and PAGE_SIZE */
122 sb
->s_blocksize
= size
;
123 sb
->s_blocksize_bits
= blksize_bits(size
);
124 return sb
->s_blocksize
;
127 EXPORT_SYMBOL(sb_set_blocksize
);
129 int sb_min_blocksize(struct super_block
*sb
, int size
)
131 int minsize
= bdev_logical_block_size(sb
->s_bdev
);
134 return sb_set_blocksize(sb
, size
);
137 EXPORT_SYMBOL(sb_min_blocksize
);
140 blkdev_get_block(struct inode
*inode
, sector_t iblock
,
141 struct buffer_head
*bh
, int create
)
143 bh
->b_bdev
= I_BDEV(inode
);
144 bh
->b_blocknr
= iblock
;
145 set_buffer_mapped(bh
);
150 blkdev_direct_IO(struct kiocb
*iocb
, struct iov_iter
*iter
, loff_t offset
)
152 struct file
*file
= iocb
->ki_filp
;
153 struct inode
*inode
= file
->f_mapping
->host
;
155 return __blockdev_direct_IO(iocb
, inode
, I_BDEV(inode
), iter
, offset
,
156 blkdev_get_block
, NULL
, NULL
,
160 int __sync_blockdev(struct block_device
*bdev
, int wait
)
165 return filemap_flush(bdev
->bd_inode
->i_mapping
);
166 return filemap_write_and_wait(bdev
->bd_inode
->i_mapping
);
170 * Write out and wait upon all the dirty data associated with a block
171 * device via its mapping. Does not take the superblock lock.
173 int sync_blockdev(struct block_device
*bdev
)
175 return __sync_blockdev(bdev
, 1);
177 EXPORT_SYMBOL(sync_blockdev
);
180 * Write out and wait upon all dirty data associated with this
181 * device. Filesystem data as well as the underlying block
182 * device. Takes the superblock lock.
184 int fsync_bdev(struct block_device
*bdev
)
186 struct super_block
*sb
= get_super(bdev
);
188 int res
= sync_filesystem(sb
);
192 return sync_blockdev(bdev
);
194 EXPORT_SYMBOL(fsync_bdev
);
197 * freeze_bdev -- lock a filesystem and force it into a consistent state
198 * @bdev: blockdevice to lock
200 * If a superblock is found on this device, we take the s_umount semaphore
201 * on it to make sure nobody unmounts until the snapshot creation is done.
202 * The reference counter (bd_fsfreeze_count) guarantees that only the last
203 * unfreeze process can unfreeze the frozen filesystem actually when multiple
204 * freeze requests arrive simultaneously. It counts up in freeze_bdev() and
205 * count down in thaw_bdev(). When it becomes 0, thaw_bdev() will unfreeze
208 struct super_block
*freeze_bdev(struct block_device
*bdev
)
210 struct super_block
*sb
;
213 mutex_lock(&bdev
->bd_fsfreeze_mutex
);
214 if (++bdev
->bd_fsfreeze_count
> 1) {
216 * We don't even need to grab a reference - the first call
217 * to freeze_bdev grab an active reference and only the last
218 * thaw_bdev drops it.
220 sb
= get_super(bdev
);
222 mutex_unlock(&bdev
->bd_fsfreeze_mutex
);
226 sb
= get_active_super(bdev
);
229 if (sb
->s_op
->freeze_super
)
230 error
= sb
->s_op
->freeze_super(sb
);
232 error
= freeze_super(sb
);
234 deactivate_super(sb
);
235 bdev
->bd_fsfreeze_count
--;
236 mutex_unlock(&bdev
->bd_fsfreeze_mutex
);
237 return ERR_PTR(error
);
239 deactivate_super(sb
);
242 mutex_unlock(&bdev
->bd_fsfreeze_mutex
);
243 return sb
; /* thaw_bdev releases s->s_umount */
245 EXPORT_SYMBOL(freeze_bdev
);
248 * thaw_bdev -- unlock filesystem
249 * @bdev: blockdevice to unlock
250 * @sb: associated superblock
252 * Unlocks the filesystem and marks it writeable again after freeze_bdev().
254 int thaw_bdev(struct block_device
*bdev
, struct super_block
*sb
)
258 mutex_lock(&bdev
->bd_fsfreeze_mutex
);
259 if (!bdev
->bd_fsfreeze_count
)
263 if (--bdev
->bd_fsfreeze_count
> 0)
269 if (sb
->s_op
->thaw_super
)
270 error
= sb
->s_op
->thaw_super(sb
);
272 error
= thaw_super(sb
);
274 bdev
->bd_fsfreeze_count
++;
275 mutex_unlock(&bdev
->bd_fsfreeze_mutex
);
279 mutex_unlock(&bdev
->bd_fsfreeze_mutex
);
282 EXPORT_SYMBOL(thaw_bdev
);
284 static int blkdev_writepage(struct page
*page
, struct writeback_control
*wbc
)
286 return block_write_full_page(page
, blkdev_get_block
, wbc
);
289 static int blkdev_readpage(struct file
* file
, struct page
* page
)
291 return block_read_full_page(page
, blkdev_get_block
);
294 static int blkdev_readpages(struct file
*file
, struct address_space
*mapping
,
295 struct list_head
*pages
, unsigned nr_pages
)
297 return mpage_readpages(mapping
, pages
, nr_pages
, blkdev_get_block
);
300 static int blkdev_write_begin(struct file
*file
, struct address_space
*mapping
,
301 loff_t pos
, unsigned len
, unsigned flags
,
302 struct page
**pagep
, void **fsdata
)
304 return block_write_begin(mapping
, pos
, len
, flags
, pagep
,
308 static int blkdev_write_end(struct file
*file
, struct address_space
*mapping
,
309 loff_t pos
, unsigned len
, unsigned copied
,
310 struct page
*page
, void *fsdata
)
313 ret
= block_write_end(file
, mapping
, pos
, len
, copied
, page
, fsdata
);
316 page_cache_release(page
);
323 * for a block special file file_inode(file)->i_size is zero
324 * so we compute the size by hand (just as in block_read/write above)
326 static loff_t
block_llseek(struct file
*file
, loff_t offset
, int whence
)
328 struct inode
*bd_inode
= file
->f_mapping
->host
;
331 mutex_lock(&bd_inode
->i_mutex
);
332 retval
= fixed_size_llseek(file
, offset
, whence
, i_size_read(bd_inode
));
333 mutex_unlock(&bd_inode
->i_mutex
);
337 int blkdev_fsync(struct file
*filp
, loff_t start
, loff_t end
, int datasync
)
339 struct inode
*bd_inode
= filp
->f_mapping
->host
;
340 struct block_device
*bdev
= I_BDEV(bd_inode
);
343 error
= filemap_write_and_wait_range(filp
->f_mapping
, start
, end
);
348 * There is no need to serialise calls to blkdev_issue_flush with
349 * i_mutex and doing so causes performance issues with concurrent
350 * O_SYNC writers to a block device.
352 error
= blkdev_issue_flush(bdev
, GFP_KERNEL
, NULL
);
353 if (error
== -EOPNOTSUPP
)
358 EXPORT_SYMBOL(blkdev_fsync
);
361 * bdev_read_page() - Start reading a page from a block device
362 * @bdev: The device to read the page from
363 * @sector: The offset on the device to read the page to (need not be aligned)
364 * @page: The page to read
366 * On entry, the page should be locked. It will be unlocked when the page
367 * has been read. If the block driver implements rw_page synchronously,
368 * that will be true on exit from this function, but it need not be.
370 * Errors returned by this function are usually "soft", eg out of memory, or
371 * queue full; callers should try a different route to read this page rather
372 * than propagate an error back up the stack.
374 * Return: negative errno if an error occurs, 0 if submission was successful.
376 int bdev_read_page(struct block_device
*bdev
, sector_t sector
,
379 const struct block_device_operations
*ops
= bdev
->bd_disk
->fops
;
380 if (!ops
->rw_page
|| bdev_get_integrity(bdev
))
382 return ops
->rw_page(bdev
, sector
+ get_start_sect(bdev
), page
, READ
);
384 EXPORT_SYMBOL_GPL(bdev_read_page
);
387 * bdev_write_page() - Start writing a page to a block device
388 * @bdev: The device to write the page to
389 * @sector: The offset on the device to write the page to (need not be aligned)
390 * @page: The page to write
391 * @wbc: The writeback_control for the write
393 * On entry, the page should be locked and not currently under writeback.
394 * On exit, if the write started successfully, the page will be unlocked and
395 * under writeback. If the write failed already (eg the driver failed to
396 * queue the page to the device), the page will still be locked. If the
397 * caller is a ->writepage implementation, it will need to unlock the page.
399 * Errors returned by this function are usually "soft", eg out of memory, or
400 * queue full; callers should try a different route to write this page rather
401 * than propagate an error back up the stack.
403 * Return: negative errno if an error occurs, 0 if submission was successful.
405 int bdev_write_page(struct block_device
*bdev
, sector_t sector
,
406 struct page
*page
, struct writeback_control
*wbc
)
409 int rw
= (wbc
->sync_mode
== WB_SYNC_ALL
) ? WRITE_SYNC
: WRITE
;
410 const struct block_device_operations
*ops
= bdev
->bd_disk
->fops
;
411 if (!ops
->rw_page
|| bdev_get_integrity(bdev
))
413 set_page_writeback(page
);
414 result
= ops
->rw_page(bdev
, sector
+ get_start_sect(bdev
), page
, rw
);
416 end_page_writeback(page
);
421 EXPORT_SYMBOL_GPL(bdev_write_page
);
424 * bdev_direct_access() - Get the address for directly-accessibly memory
425 * @bdev: The device containing the memory
426 * @sector: The offset within the device
427 * @addr: Where to put the address of the memory
428 * @pfn: The Page Frame Number for the memory
429 * @size: The number of bytes requested
431 * If a block device is made up of directly addressable memory, this function
432 * will tell the caller the PFN and the address of the memory. The address
433 * may be directly dereferenced within the kernel without the need to call
434 * ioremap(), kmap() or similar. The PFN is suitable for inserting into
437 * Return: negative errno if an error occurs, otherwise the number of bytes
438 * accessible at this address.
440 long bdev_direct_access(struct block_device
*bdev
, sector_t sector
,
441 void **addr
, unsigned long *pfn
, long size
)
444 const struct block_device_operations
*ops
= bdev
->bd_disk
->fops
;
448 if (!ops
->direct_access
)
450 if ((sector
+ DIV_ROUND_UP(size
, 512)) >
451 part_nr_sects_read(bdev
->bd_part
))
453 sector
+= get_start_sect(bdev
);
454 if (sector
% (PAGE_SIZE
/ 512))
456 avail
= ops
->direct_access(bdev
, sector
, addr
, pfn
, size
);
459 return min(avail
, size
);
461 EXPORT_SYMBOL_GPL(bdev_direct_access
);
467 static __cacheline_aligned_in_smp
DEFINE_SPINLOCK(bdev_lock
);
468 static struct kmem_cache
* bdev_cachep __read_mostly
;
470 static struct inode
*bdev_alloc_inode(struct super_block
*sb
)
472 struct bdev_inode
*ei
= kmem_cache_alloc(bdev_cachep
, GFP_KERNEL
);
475 return &ei
->vfs_inode
;
478 static void bdev_i_callback(struct rcu_head
*head
)
480 struct inode
*inode
= container_of(head
, struct inode
, i_rcu
);
481 struct bdev_inode
*bdi
= BDEV_I(inode
);
483 kmem_cache_free(bdev_cachep
, bdi
);
486 static void bdev_destroy_inode(struct inode
*inode
)
488 call_rcu(&inode
->i_rcu
, bdev_i_callback
);
491 static void init_once(void *foo
)
493 struct bdev_inode
*ei
= (struct bdev_inode
*) foo
;
494 struct block_device
*bdev
= &ei
->bdev
;
496 memset(bdev
, 0, sizeof(*bdev
));
497 mutex_init(&bdev
->bd_mutex
);
498 INIT_LIST_HEAD(&bdev
->bd_inodes
);
499 INIT_LIST_HEAD(&bdev
->bd_list
);
501 INIT_LIST_HEAD(&bdev
->bd_holder_disks
);
503 inode_init_once(&ei
->vfs_inode
);
504 /* Initialize mutex for freeze. */
505 mutex_init(&bdev
->bd_fsfreeze_mutex
);
508 static inline void __bd_forget(struct inode
*inode
)
510 list_del_init(&inode
->i_devices
);
511 inode
->i_bdev
= NULL
;
512 inode
->i_mapping
= &inode
->i_data
;
515 static void bdev_evict_inode(struct inode
*inode
)
517 struct block_device
*bdev
= &BDEV_I(inode
)->bdev
;
519 truncate_inode_pages_final(&inode
->i_data
);
520 invalidate_inode_buffers(inode
); /* is it needed here? */
522 spin_lock(&bdev_lock
);
523 while ( (p
= bdev
->bd_inodes
.next
) != &bdev
->bd_inodes
) {
524 __bd_forget(list_entry(p
, struct inode
, i_devices
));
526 list_del_init(&bdev
->bd_list
);
527 spin_unlock(&bdev_lock
);
530 static const struct super_operations bdev_sops
= {
531 .statfs
= simple_statfs
,
532 .alloc_inode
= bdev_alloc_inode
,
533 .destroy_inode
= bdev_destroy_inode
,
534 .drop_inode
= generic_delete_inode
,
535 .evict_inode
= bdev_evict_inode
,
538 static struct dentry
*bd_mount(struct file_system_type
*fs_type
,
539 int flags
, const char *dev_name
, void *data
)
541 return mount_pseudo(fs_type
, "bdev:", &bdev_sops
, NULL
, BDEVFS_MAGIC
);
544 static struct file_system_type bd_type
= {
547 .kill_sb
= kill_anon_super
,
550 struct super_block
*blockdev_superblock __read_mostly
;
551 EXPORT_SYMBOL_GPL(blockdev_superblock
);
553 void __init
bdev_cache_init(void)
556 static struct vfsmount
*bd_mnt
;
558 bdev_cachep
= kmem_cache_create("bdev_cache", sizeof(struct bdev_inode
),
559 0, (SLAB_HWCACHE_ALIGN
|SLAB_RECLAIM_ACCOUNT
|
560 SLAB_MEM_SPREAD
|SLAB_PANIC
),
562 err
= register_filesystem(&bd_type
);
564 panic("Cannot register bdev pseudo-fs");
565 bd_mnt
= kern_mount(&bd_type
);
567 panic("Cannot create bdev pseudo-fs");
568 blockdev_superblock
= bd_mnt
->mnt_sb
; /* For writeback */
572 * Most likely _very_ bad one - but then it's hardly critical for small
573 * /dev and can be fixed when somebody will need really large one.
574 * Keep in mind that it will be fed through icache hash function too.
576 static inline unsigned long hash(dev_t dev
)
578 return MAJOR(dev
)+MINOR(dev
);
581 static int bdev_test(struct inode
*inode
, void *data
)
583 return BDEV_I(inode
)->bdev
.bd_dev
== *(dev_t
*)data
;
586 static int bdev_set(struct inode
*inode
, void *data
)
588 BDEV_I(inode
)->bdev
.bd_dev
= *(dev_t
*)data
;
592 static LIST_HEAD(all_bdevs
);
594 struct block_device
*bdget(dev_t dev
)
596 struct block_device
*bdev
;
599 inode
= iget5_locked(blockdev_superblock
, hash(dev
),
600 bdev_test
, bdev_set
, &dev
);
605 bdev
= &BDEV_I(inode
)->bdev
;
607 if (inode
->i_state
& I_NEW
) {
608 bdev
->bd_contains
= NULL
;
609 bdev
->bd_super
= NULL
;
610 bdev
->bd_inode
= inode
;
611 bdev
->bd_block_size
= (1 << inode
->i_blkbits
);
612 bdev
->bd_part_count
= 0;
613 bdev
->bd_invalidated
= 0;
614 inode
->i_mode
= S_IFBLK
;
616 inode
->i_bdev
= bdev
;
617 inode
->i_data
.a_ops
= &def_blk_aops
;
618 mapping_set_gfp_mask(&inode
->i_data
, GFP_USER
);
619 spin_lock(&bdev_lock
);
620 list_add(&bdev
->bd_list
, &all_bdevs
);
621 spin_unlock(&bdev_lock
);
622 unlock_new_inode(inode
);
627 EXPORT_SYMBOL(bdget
);
630 * bdgrab -- Grab a reference to an already referenced block device
631 * @bdev: Block device to grab a reference to.
633 struct block_device
*bdgrab(struct block_device
*bdev
)
635 ihold(bdev
->bd_inode
);
638 EXPORT_SYMBOL(bdgrab
);
640 long nr_blockdev_pages(void)
642 struct block_device
*bdev
;
644 spin_lock(&bdev_lock
);
645 list_for_each_entry(bdev
, &all_bdevs
, bd_list
) {
646 ret
+= bdev
->bd_inode
->i_mapping
->nrpages
;
648 spin_unlock(&bdev_lock
);
652 void bdput(struct block_device
*bdev
)
654 iput(bdev
->bd_inode
);
657 EXPORT_SYMBOL(bdput
);
659 static struct block_device
*bd_acquire(struct inode
*inode
)
661 struct block_device
*bdev
;
663 spin_lock(&bdev_lock
);
664 bdev
= inode
->i_bdev
;
666 ihold(bdev
->bd_inode
);
667 spin_unlock(&bdev_lock
);
670 spin_unlock(&bdev_lock
);
672 bdev
= bdget(inode
->i_rdev
);
674 spin_lock(&bdev_lock
);
675 if (!inode
->i_bdev
) {
677 * We take an additional reference to bd_inode,
678 * and it's released in clear_inode() of inode.
679 * So, we can access it via ->i_mapping always
682 ihold(bdev
->bd_inode
);
683 inode
->i_bdev
= bdev
;
684 inode
->i_mapping
= bdev
->bd_inode
->i_mapping
;
685 list_add(&inode
->i_devices
, &bdev
->bd_inodes
);
687 spin_unlock(&bdev_lock
);
692 /* Call when you free inode */
694 void bd_forget(struct inode
*inode
)
696 struct block_device
*bdev
= NULL
;
698 spin_lock(&bdev_lock
);
699 if (!sb_is_blkdev_sb(inode
->i_sb
))
700 bdev
= inode
->i_bdev
;
702 spin_unlock(&bdev_lock
);
705 iput(bdev
->bd_inode
);
709 * bd_may_claim - test whether a block device can be claimed
710 * @bdev: block device of interest
711 * @whole: whole block device containing @bdev, may equal @bdev
712 * @holder: holder trying to claim @bdev
714 * Test whether @bdev can be claimed by @holder.
717 * spin_lock(&bdev_lock).
720 * %true if @bdev can be claimed, %false otherwise.
722 static bool bd_may_claim(struct block_device
*bdev
, struct block_device
*whole
,
725 if (bdev
->bd_holder
== holder
)
726 return true; /* already a holder */
727 else if (bdev
->bd_holder
!= NULL
)
728 return false; /* held by someone else */
729 else if (bdev
->bd_contains
== bdev
)
730 return true; /* is a whole device which isn't held */
732 else if (whole
->bd_holder
== bd_may_claim
)
733 return true; /* is a partition of a device that is being partitioned */
734 else if (whole
->bd_holder
!= NULL
)
735 return false; /* is a partition of a held device */
737 return true; /* is a partition of an un-held device */
741 * bd_prepare_to_claim - prepare to claim a block device
742 * @bdev: block device of interest
743 * @whole: the whole device containing @bdev, may equal @bdev
744 * @holder: holder trying to claim @bdev
746 * Prepare to claim @bdev. This function fails if @bdev is already
747 * claimed by another holder and waits if another claiming is in
748 * progress. This function doesn't actually claim. On successful
749 * return, the caller has ownership of bd_claiming and bd_holder[s].
752 * spin_lock(&bdev_lock). Might release bdev_lock, sleep and regrab
756 * 0 if @bdev can be claimed, -EBUSY otherwise.
758 static int bd_prepare_to_claim(struct block_device
*bdev
,
759 struct block_device
*whole
, void *holder
)
762 /* if someone else claimed, fail */
763 if (!bd_may_claim(bdev
, whole
, holder
))
766 /* if claiming is already in progress, wait for it to finish */
767 if (whole
->bd_claiming
) {
768 wait_queue_head_t
*wq
= bit_waitqueue(&whole
->bd_claiming
, 0);
771 prepare_to_wait(wq
, &wait
, TASK_UNINTERRUPTIBLE
);
772 spin_unlock(&bdev_lock
);
774 finish_wait(wq
, &wait
);
775 spin_lock(&bdev_lock
);
784 * bd_start_claiming - start claiming a block device
785 * @bdev: block device of interest
786 * @holder: holder trying to claim @bdev
788 * @bdev is about to be opened exclusively. Check @bdev can be opened
789 * exclusively and mark that an exclusive open is in progress. Each
790 * successful call to this function must be matched with a call to
791 * either bd_finish_claiming() or bd_abort_claiming() (which do not
794 * This function is used to gain exclusive access to the block device
795 * without actually causing other exclusive open attempts to fail. It
796 * should be used when the open sequence itself requires exclusive
797 * access but may subsequently fail.
803 * Pointer to the block device containing @bdev on success, ERR_PTR()
806 static struct block_device
*bd_start_claiming(struct block_device
*bdev
,
809 struct gendisk
*disk
;
810 struct block_device
*whole
;
816 * @bdev might not have been initialized properly yet, look up
817 * and grab the outer block device the hard way.
819 disk
= get_gendisk(bdev
->bd_dev
, &partno
);
821 return ERR_PTR(-ENXIO
);
824 * Normally, @bdev should equal what's returned from bdget_disk()
825 * if partno is 0; however, some drivers (floppy) use multiple
826 * bdev's for the same physical device and @bdev may be one of the
827 * aliases. Keep @bdev if partno is 0. This means claimer
828 * tracking is broken for those devices but it has always been that
832 whole
= bdget_disk(disk
, 0);
834 whole
= bdgrab(bdev
);
836 module_put(disk
->fops
->owner
);
839 return ERR_PTR(-ENOMEM
);
841 /* prepare to claim, if successful, mark claiming in progress */
842 spin_lock(&bdev_lock
);
844 err
= bd_prepare_to_claim(bdev
, whole
, holder
);
846 whole
->bd_claiming
= holder
;
847 spin_unlock(&bdev_lock
);
850 spin_unlock(&bdev_lock
);
857 struct bd_holder_disk
{
858 struct list_head list
;
859 struct gendisk
*disk
;
863 static struct bd_holder_disk
*bd_find_holder_disk(struct block_device
*bdev
,
864 struct gendisk
*disk
)
866 struct bd_holder_disk
*holder
;
868 list_for_each_entry(holder
, &bdev
->bd_holder_disks
, list
)
869 if (holder
->disk
== disk
)
874 static int add_symlink(struct kobject
*from
, struct kobject
*to
)
876 return sysfs_create_link(from
, to
, kobject_name(to
));
879 static void del_symlink(struct kobject
*from
, struct kobject
*to
)
881 sysfs_remove_link(from
, kobject_name(to
));
885 * bd_link_disk_holder - create symlinks between holding disk and slave bdev
886 * @bdev: the claimed slave bdev
887 * @disk: the holding disk
889 * DON'T USE THIS UNLESS YOU'RE ALREADY USING IT.
891 * This functions creates the following sysfs symlinks.
893 * - from "slaves" directory of the holder @disk to the claimed @bdev
894 * - from "holders" directory of the @bdev to the holder @disk
896 * For example, if /dev/dm-0 maps to /dev/sda and disk for dm-0 is
897 * passed to bd_link_disk_holder(), then:
899 * /sys/block/dm-0/slaves/sda --> /sys/block/sda
900 * /sys/block/sda/holders/dm-0 --> /sys/block/dm-0
902 * The caller must have claimed @bdev before calling this function and
903 * ensure that both @bdev and @disk are valid during the creation and
904 * lifetime of these symlinks.
910 * 0 on success, -errno on failure.
912 int bd_link_disk_holder(struct block_device
*bdev
, struct gendisk
*disk
)
914 struct bd_holder_disk
*holder
;
917 mutex_lock(&bdev
->bd_mutex
);
919 WARN_ON_ONCE(!bdev
->bd_holder
);
921 /* FIXME: remove the following once add_disk() handles errors */
922 if (WARN_ON(!disk
->slave_dir
|| !bdev
->bd_part
->holder_dir
))
925 holder
= bd_find_holder_disk(bdev
, disk
);
931 holder
= kzalloc(sizeof(*holder
), GFP_KERNEL
);
937 INIT_LIST_HEAD(&holder
->list
);
941 ret
= add_symlink(disk
->slave_dir
, &part_to_dev(bdev
->bd_part
)->kobj
);
945 ret
= add_symlink(bdev
->bd_part
->holder_dir
, &disk_to_dev(disk
)->kobj
);
949 * bdev could be deleted beneath us which would implicitly destroy
950 * the holder directory. Hold on to it.
952 kobject_get(bdev
->bd_part
->holder_dir
);
954 list_add(&holder
->list
, &bdev
->bd_holder_disks
);
958 del_symlink(disk
->slave_dir
, &part_to_dev(bdev
->bd_part
)->kobj
);
962 mutex_unlock(&bdev
->bd_mutex
);
965 EXPORT_SYMBOL_GPL(bd_link_disk_holder
);
968 * bd_unlink_disk_holder - destroy symlinks created by bd_link_disk_holder()
969 * @bdev: the calimed slave bdev
970 * @disk: the holding disk
972 * DON'T USE THIS UNLESS YOU'RE ALREADY USING IT.
977 void bd_unlink_disk_holder(struct block_device
*bdev
, struct gendisk
*disk
)
979 struct bd_holder_disk
*holder
;
981 mutex_lock(&bdev
->bd_mutex
);
983 holder
= bd_find_holder_disk(bdev
, disk
);
985 if (!WARN_ON_ONCE(holder
== NULL
) && !--holder
->refcnt
) {
986 del_symlink(disk
->slave_dir
, &part_to_dev(bdev
->bd_part
)->kobj
);
987 del_symlink(bdev
->bd_part
->holder_dir
,
988 &disk_to_dev(disk
)->kobj
);
989 kobject_put(bdev
->bd_part
->holder_dir
);
990 list_del_init(&holder
->list
);
994 mutex_unlock(&bdev
->bd_mutex
);
996 EXPORT_SYMBOL_GPL(bd_unlink_disk_holder
);
1000 * flush_disk - invalidates all buffer-cache entries on a disk
1002 * @bdev: struct block device to be flushed
1003 * @kill_dirty: flag to guide handling of dirty inodes
1005 * Invalidates all buffer-cache entries on a disk. It should be called
1006 * when a disk has been changed -- either by a media change or online
1009 static void flush_disk(struct block_device
*bdev
, bool kill_dirty
)
1011 if (__invalidate_device(bdev
, kill_dirty
)) {
1012 char name
[BDEVNAME_SIZE
] = "";
1015 disk_name(bdev
->bd_disk
, 0, name
);
1016 printk(KERN_WARNING
"VFS: busy inodes on changed media or "
1017 "resized disk %s\n", name
);
1022 if (disk_part_scan_enabled(bdev
->bd_disk
))
1023 bdev
->bd_invalidated
= 1;
1027 * check_disk_size_change - checks for disk size change and adjusts bdev size.
1028 * @disk: struct gendisk to check
1029 * @bdev: struct bdev to adjust.
1031 * This routine checks to see if the bdev size does not match the disk size
1032 * and adjusts it if it differs.
1034 void check_disk_size_change(struct gendisk
*disk
, struct block_device
*bdev
)
1036 loff_t disk_size
, bdev_size
;
1038 disk_size
= (loff_t
)get_capacity(disk
) << 9;
1039 bdev_size
= i_size_read(bdev
->bd_inode
);
1040 if (disk_size
!= bdev_size
) {
1041 char name
[BDEVNAME_SIZE
];
1043 disk_name(disk
, 0, name
);
1045 "%s: detected capacity change from %lld to %lld\n",
1046 name
, bdev_size
, disk_size
);
1047 i_size_write(bdev
->bd_inode
, disk_size
);
1048 flush_disk(bdev
, false);
1051 EXPORT_SYMBOL(check_disk_size_change
);
1054 * revalidate_disk - wrapper for lower-level driver's revalidate_disk call-back
1055 * @disk: struct gendisk to be revalidated
1057 * This routine is a wrapper for lower-level driver's revalidate_disk
1058 * call-backs. It is used to do common pre and post operations needed
1059 * for all revalidate_disk operations.
1061 int revalidate_disk(struct gendisk
*disk
)
1063 struct block_device
*bdev
;
1066 if (disk
->fops
->revalidate_disk
)
1067 ret
= disk
->fops
->revalidate_disk(disk
);
1069 bdev
= bdget_disk(disk
, 0);
1073 mutex_lock(&bdev
->bd_mutex
);
1074 check_disk_size_change(disk
, bdev
);
1075 bdev
->bd_invalidated
= 0;
1076 mutex_unlock(&bdev
->bd_mutex
);
1080 EXPORT_SYMBOL(revalidate_disk
);
1083 * This routine checks whether a removable media has been changed,
1084 * and invalidates all buffer-cache-entries in that case. This
1085 * is a relatively slow routine, so we have to try to minimize using
1086 * it. Thus it is called only upon a 'mount' or 'open'. This
1087 * is the best way of combining speed and utility, I think.
1088 * People changing diskettes in the middle of an operation deserve
1091 int check_disk_change(struct block_device
*bdev
)
1093 struct gendisk
*disk
= bdev
->bd_disk
;
1094 const struct block_device_operations
*bdops
= disk
->fops
;
1095 unsigned int events
;
1097 events
= disk_clear_events(disk
, DISK_EVENT_MEDIA_CHANGE
|
1098 DISK_EVENT_EJECT_REQUEST
);
1099 if (!(events
& DISK_EVENT_MEDIA_CHANGE
))
1102 flush_disk(bdev
, true);
1103 if (bdops
->revalidate_disk
)
1104 bdops
->revalidate_disk(bdev
->bd_disk
);
1108 EXPORT_SYMBOL(check_disk_change
);
1110 void bd_set_size(struct block_device
*bdev
, loff_t size
)
1112 unsigned bsize
= bdev_logical_block_size(bdev
);
1114 mutex_lock(&bdev
->bd_inode
->i_mutex
);
1115 i_size_write(bdev
->bd_inode
, size
);
1116 mutex_unlock(&bdev
->bd_inode
->i_mutex
);
1117 while (bsize
< PAGE_CACHE_SIZE
) {
1122 bdev
->bd_block_size
= bsize
;
1123 bdev
->bd_inode
->i_blkbits
= blksize_bits(bsize
);
1125 EXPORT_SYMBOL(bd_set_size
);
1127 static void __blkdev_put(struct block_device
*bdev
, fmode_t mode
, int for_part
);
1132 * mutex_lock(part->bd_mutex)
1133 * mutex_lock_nested(whole->bd_mutex, 1)
1136 static int __blkdev_get(struct block_device
*bdev
, fmode_t mode
, int for_part
)
1138 struct gendisk
*disk
;
1139 struct module
*owner
;
1144 if (mode
& FMODE_READ
)
1146 if (mode
& FMODE_WRITE
)
1149 * hooks: /n/, see "layering violations".
1152 ret
= devcgroup_inode_permission(bdev
->bd_inode
, perm
);
1162 disk
= get_gendisk(bdev
->bd_dev
, &partno
);
1165 owner
= disk
->fops
->owner
;
1167 disk_block_events(disk
);
1168 mutex_lock_nested(&bdev
->bd_mutex
, for_part
);
1169 if (!bdev
->bd_openers
) {
1170 bdev
->bd_disk
= disk
;
1171 bdev
->bd_queue
= disk
->queue
;
1172 bdev
->bd_contains
= bdev
;
1175 bdev
->bd_part
= disk_get_part(disk
, partno
);
1180 if (disk
->fops
->open
) {
1181 ret
= disk
->fops
->open(bdev
, mode
);
1182 if (ret
== -ERESTARTSYS
) {
1183 /* Lost a race with 'disk' being
1184 * deleted, try again.
1187 disk_put_part(bdev
->bd_part
);
1188 bdev
->bd_part
= NULL
;
1189 bdev
->bd_disk
= NULL
;
1190 bdev
->bd_queue
= NULL
;
1191 mutex_unlock(&bdev
->bd_mutex
);
1192 disk_unblock_events(disk
);
1200 bd_set_size(bdev
,(loff_t
)get_capacity(disk
)<<9);
1203 * If the device is invalidated, rescan partition
1204 * if open succeeded or failed with -ENOMEDIUM.
1205 * The latter is necessary to prevent ghost
1206 * partitions on a removed medium.
1208 if (bdev
->bd_invalidated
) {
1210 rescan_partitions(disk
, bdev
);
1211 else if (ret
== -ENOMEDIUM
)
1212 invalidate_partitions(disk
, bdev
);
1217 struct block_device
*whole
;
1218 whole
= bdget_disk(disk
, 0);
1223 ret
= __blkdev_get(whole
, mode
, 1);
1226 bdev
->bd_contains
= whole
;
1227 bdev
->bd_part
= disk_get_part(disk
, partno
);
1228 if (!(disk
->flags
& GENHD_FL_UP
) ||
1229 !bdev
->bd_part
|| !bdev
->bd_part
->nr_sects
) {
1233 bd_set_size(bdev
, (loff_t
)bdev
->bd_part
->nr_sects
<< 9);
1236 if (bdev
->bd_contains
== bdev
) {
1238 if (bdev
->bd_disk
->fops
->open
)
1239 ret
= bdev
->bd_disk
->fops
->open(bdev
, mode
);
1240 /* the same as first opener case, read comment there */
1241 if (bdev
->bd_invalidated
) {
1243 rescan_partitions(bdev
->bd_disk
, bdev
);
1244 else if (ret
== -ENOMEDIUM
)
1245 invalidate_partitions(bdev
->bd_disk
, bdev
);
1248 goto out_unlock_bdev
;
1250 /* only one opener holds refs to the module and disk */
1256 bdev
->bd_part_count
++;
1257 mutex_unlock(&bdev
->bd_mutex
);
1258 disk_unblock_events(disk
);
1262 disk_put_part(bdev
->bd_part
);
1263 bdev
->bd_disk
= NULL
;
1264 bdev
->bd_part
= NULL
;
1265 bdev
->bd_queue
= NULL
;
1266 if (bdev
!= bdev
->bd_contains
)
1267 __blkdev_put(bdev
->bd_contains
, mode
, 1);
1268 bdev
->bd_contains
= NULL
;
1270 mutex_unlock(&bdev
->bd_mutex
);
1271 disk_unblock_events(disk
);
1281 * blkdev_get - open a block device
1282 * @bdev: block_device to open
1283 * @mode: FMODE_* mask
1284 * @holder: exclusive holder identifier
1286 * Open @bdev with @mode. If @mode includes %FMODE_EXCL, @bdev is
1287 * open with exclusive access. Specifying %FMODE_EXCL with %NULL
1288 * @holder is invalid. Exclusive opens may nest for the same @holder.
1290 * On success, the reference count of @bdev is unchanged. On failure,
1297 * 0 on success, -errno on failure.
1299 int blkdev_get(struct block_device
*bdev
, fmode_t mode
, void *holder
)
1301 struct block_device
*whole
= NULL
;
1304 WARN_ON_ONCE((mode
& FMODE_EXCL
) && !holder
);
1306 if ((mode
& FMODE_EXCL
) && holder
) {
1307 whole
= bd_start_claiming(bdev
, holder
);
1308 if (IS_ERR(whole
)) {
1310 return PTR_ERR(whole
);
1314 res
= __blkdev_get(bdev
, mode
, 0);
1317 struct gendisk
*disk
= whole
->bd_disk
;
1319 /* finish claiming */
1320 mutex_lock(&bdev
->bd_mutex
);
1321 spin_lock(&bdev_lock
);
1324 BUG_ON(!bd_may_claim(bdev
, whole
, holder
));
1326 * Note that for a whole device bd_holders
1327 * will be incremented twice, and bd_holder
1328 * will be set to bd_may_claim before being
1331 whole
->bd_holders
++;
1332 whole
->bd_holder
= bd_may_claim
;
1334 bdev
->bd_holder
= holder
;
1337 /* tell others that we're done */
1338 BUG_ON(whole
->bd_claiming
!= holder
);
1339 whole
->bd_claiming
= NULL
;
1340 wake_up_bit(&whole
->bd_claiming
, 0);
1342 spin_unlock(&bdev_lock
);
1345 * Block event polling for write claims if requested. Any
1346 * write holder makes the write_holder state stick until
1347 * all are released. This is good enough and tracking
1348 * individual writeable reference is too fragile given the
1349 * way @mode is used in blkdev_get/put().
1351 if (!res
&& (mode
& FMODE_WRITE
) && !bdev
->bd_write_holder
&&
1352 (disk
->flags
& GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE
)) {
1353 bdev
->bd_write_holder
= true;
1354 disk_block_events(disk
);
1357 mutex_unlock(&bdev
->bd_mutex
);
1363 EXPORT_SYMBOL(blkdev_get
);
1366 * blkdev_get_by_path - open a block device by name
1367 * @path: path to the block device to open
1368 * @mode: FMODE_* mask
1369 * @holder: exclusive holder identifier
1371 * Open the blockdevice described by the device file at @path. @mode
1372 * and @holder are identical to blkdev_get().
1374 * On success, the returned block_device has reference count of one.
1380 * Pointer to block_device on success, ERR_PTR(-errno) on failure.
1382 struct block_device
*blkdev_get_by_path(const char *path
, fmode_t mode
,
1385 struct block_device
*bdev
;
1388 bdev
= lookup_bdev(path
);
1392 err
= blkdev_get(bdev
, mode
, holder
);
1394 return ERR_PTR(err
);
1396 if ((mode
& FMODE_WRITE
) && bdev_read_only(bdev
)) {
1397 blkdev_put(bdev
, mode
);
1398 return ERR_PTR(-EACCES
);
1403 EXPORT_SYMBOL(blkdev_get_by_path
);
1406 * blkdev_get_by_dev - open a block device by device number
1407 * @dev: device number of block device to open
1408 * @mode: FMODE_* mask
1409 * @holder: exclusive holder identifier
1411 * Open the blockdevice described by device number @dev. @mode and
1412 * @holder are identical to blkdev_get().
1414 * Use it ONLY if you really do not have anything better - i.e. when
1415 * you are behind a truly sucky interface and all you are given is a
1416 * device number. _Never_ to be used for internal purposes. If you
1417 * ever need it - reconsider your API.
1419 * On success, the returned block_device has reference count of one.
1425 * Pointer to block_device on success, ERR_PTR(-errno) on failure.
1427 struct block_device
*blkdev_get_by_dev(dev_t dev
, fmode_t mode
, void *holder
)
1429 struct block_device
*bdev
;
1434 return ERR_PTR(-ENOMEM
);
1436 err
= blkdev_get(bdev
, mode
, holder
);
1438 return ERR_PTR(err
);
1442 EXPORT_SYMBOL(blkdev_get_by_dev
);
1444 static int blkdev_open(struct inode
* inode
, struct file
* filp
)
1446 struct block_device
*bdev
;
1449 * Preserve backwards compatibility and allow large file access
1450 * even if userspace doesn't ask for it explicitly. Some mkfs
1451 * binary needs it. We might want to drop this workaround
1452 * during an unstable branch.
1454 filp
->f_flags
|= O_LARGEFILE
;
1456 if (filp
->f_flags
& O_NDELAY
)
1457 filp
->f_mode
|= FMODE_NDELAY
;
1458 if (filp
->f_flags
& O_EXCL
)
1459 filp
->f_mode
|= FMODE_EXCL
;
1460 if ((filp
->f_flags
& O_ACCMODE
) == 3)
1461 filp
->f_mode
|= FMODE_WRITE_IOCTL
;
1463 bdev
= bd_acquire(inode
);
1467 filp
->f_mapping
= bdev
->bd_inode
->i_mapping
;
1469 return blkdev_get(bdev
, filp
->f_mode
, filp
);
1472 static void __blkdev_put(struct block_device
*bdev
, fmode_t mode
, int for_part
)
1474 struct gendisk
*disk
= bdev
->bd_disk
;
1475 struct block_device
*victim
= NULL
;
1477 mutex_lock_nested(&bdev
->bd_mutex
, for_part
);
1479 bdev
->bd_part_count
--;
1481 if (!--bdev
->bd_openers
) {
1482 WARN_ON_ONCE(bdev
->bd_holders
);
1483 sync_blockdev(bdev
);
1486 * ->release can cause the queue to disappear, so flush all
1487 * dirty data before.
1489 bdev_write_inode(bdev
->bd_inode
);
1491 if (bdev
->bd_contains
== bdev
) {
1492 if (disk
->fops
->release
)
1493 disk
->fops
->release(disk
, mode
);
1495 if (!bdev
->bd_openers
) {
1496 struct module
*owner
= disk
->fops
->owner
;
1498 disk_put_part(bdev
->bd_part
);
1499 bdev
->bd_part
= NULL
;
1500 bdev
->bd_disk
= NULL
;
1501 if (bdev
!= bdev
->bd_contains
)
1502 victim
= bdev
->bd_contains
;
1503 bdev
->bd_contains
= NULL
;
1508 mutex_unlock(&bdev
->bd_mutex
);
1511 __blkdev_put(victim
, mode
, 1);
1514 void blkdev_put(struct block_device
*bdev
, fmode_t mode
)
1516 mutex_lock(&bdev
->bd_mutex
);
1518 if (mode
& FMODE_EXCL
) {
1522 * Release a claim on the device. The holder fields
1523 * are protected with bdev_lock. bd_mutex is to
1524 * synchronize disk_holder unlinking.
1526 spin_lock(&bdev_lock
);
1528 WARN_ON_ONCE(--bdev
->bd_holders
< 0);
1529 WARN_ON_ONCE(--bdev
->bd_contains
->bd_holders
< 0);
1531 /* bd_contains might point to self, check in a separate step */
1532 if ((bdev_free
= !bdev
->bd_holders
))
1533 bdev
->bd_holder
= NULL
;
1534 if (!bdev
->bd_contains
->bd_holders
)
1535 bdev
->bd_contains
->bd_holder
= NULL
;
1537 spin_unlock(&bdev_lock
);
1540 * If this was the last claim, remove holder link and
1541 * unblock evpoll if it was a write holder.
1543 if (bdev_free
&& bdev
->bd_write_holder
) {
1544 disk_unblock_events(bdev
->bd_disk
);
1545 bdev
->bd_write_holder
= false;
1550 * Trigger event checking and tell drivers to flush MEDIA_CHANGE
1551 * event. This is to ensure detection of media removal commanded
1552 * from userland - e.g. eject(1).
1554 disk_flush_events(bdev
->bd_disk
, DISK_EVENT_MEDIA_CHANGE
);
1556 mutex_unlock(&bdev
->bd_mutex
);
1558 __blkdev_put(bdev
, mode
, 0);
1560 EXPORT_SYMBOL(blkdev_put
);
1562 static int blkdev_close(struct inode
* inode
, struct file
* filp
)
1564 struct block_device
*bdev
= I_BDEV(filp
->f_mapping
->host
);
1565 blkdev_put(bdev
, filp
->f_mode
);
1569 static long block_ioctl(struct file
*file
, unsigned cmd
, unsigned long arg
)
1571 struct block_device
*bdev
= I_BDEV(file
->f_mapping
->host
);
1572 fmode_t mode
= file
->f_mode
;
1575 * O_NDELAY can be altered using fcntl(.., F_SETFL, ..), so we have
1576 * to updated it before every ioctl.
1578 if (file
->f_flags
& O_NDELAY
)
1579 mode
|= FMODE_NDELAY
;
1581 mode
&= ~FMODE_NDELAY
;
1583 return blkdev_ioctl(bdev
, mode
, cmd
, arg
);
1587 * Write data to the block device. Only intended for the block device itself
1588 * and the raw driver which basically is a fake block device.
1590 * Does not take i_mutex for the write and thus is not for general purpose
1593 ssize_t
blkdev_write_iter(struct kiocb
*iocb
, struct iov_iter
*from
)
1595 struct file
*file
= iocb
->ki_filp
;
1596 struct inode
*bd_inode
= file
->f_mapping
->host
;
1597 loff_t size
= i_size_read(bd_inode
);
1598 struct blk_plug plug
;
1601 if (bdev_read_only(I_BDEV(bd_inode
)))
1604 if (!iov_iter_count(from
))
1607 if (iocb
->ki_pos
>= size
)
1610 iov_iter_truncate(from
, size
- iocb
->ki_pos
);
1612 blk_start_plug(&plug
);
1613 ret
= __generic_file_write_iter(iocb
, from
);
1616 err
= generic_write_sync(file
, iocb
->ki_pos
- ret
, ret
);
1620 blk_finish_plug(&plug
);
1623 EXPORT_SYMBOL_GPL(blkdev_write_iter
);
1625 ssize_t
blkdev_read_iter(struct kiocb
*iocb
, struct iov_iter
*to
)
1627 struct file
*file
= iocb
->ki_filp
;
1628 struct inode
*bd_inode
= file
->f_mapping
->host
;
1629 loff_t size
= i_size_read(bd_inode
);
1630 loff_t pos
= iocb
->ki_pos
;
1636 iov_iter_truncate(to
, size
);
1637 return generic_file_read_iter(iocb
, to
);
1639 EXPORT_SYMBOL_GPL(blkdev_read_iter
);
1642 * Try to release a page associated with block device when the system
1643 * is under memory pressure.
1645 static int blkdev_releasepage(struct page
*page
, gfp_t wait
)
1647 struct super_block
*super
= BDEV_I(page
->mapping
->host
)->bdev
.bd_super
;
1649 if (super
&& super
->s_op
->bdev_try_to_free_page
)
1650 return super
->s_op
->bdev_try_to_free_page(super
, page
, wait
);
1652 return try_to_free_buffers(page
);
1655 static const struct address_space_operations def_blk_aops
= {
1656 .readpage
= blkdev_readpage
,
1657 .readpages
= blkdev_readpages
,
1658 .writepage
= blkdev_writepage
,
1659 .write_begin
= blkdev_write_begin
,
1660 .write_end
= blkdev_write_end
,
1661 .writepages
= generic_writepages
,
1662 .releasepage
= blkdev_releasepage
,
1663 .direct_IO
= blkdev_direct_IO
,
1664 .is_dirty_writeback
= buffer_check_dirty_writeback
,
1667 const struct file_operations def_blk_fops
= {
1668 .open
= blkdev_open
,
1669 .release
= blkdev_close
,
1670 .llseek
= block_llseek
,
1671 .read_iter
= blkdev_read_iter
,
1672 .write_iter
= blkdev_write_iter
,
1673 .mmap
= generic_file_mmap
,
1674 .fsync
= blkdev_fsync
,
1675 .unlocked_ioctl
= block_ioctl
,
1676 #ifdef CONFIG_COMPAT
1677 .compat_ioctl
= compat_blkdev_ioctl
,
1679 .splice_read
= generic_file_splice_read
,
1680 .splice_write
= iter_file_splice_write
,
1683 int ioctl_by_bdev(struct block_device
*bdev
, unsigned cmd
, unsigned long arg
)
1686 mm_segment_t old_fs
= get_fs();
1688 res
= blkdev_ioctl(bdev
, 0, cmd
, arg
);
1693 EXPORT_SYMBOL(ioctl_by_bdev
);
1696 * lookup_bdev - lookup a struct block_device by name
1697 * @pathname: special file representing the block device
1699 * Get a reference to the blockdevice at @pathname in the current
1700 * namespace if possible and return it. Return ERR_PTR(error)
1703 struct block_device
*lookup_bdev(const char *pathname
)
1705 struct block_device
*bdev
;
1706 struct inode
*inode
;
1710 if (!pathname
|| !*pathname
)
1711 return ERR_PTR(-EINVAL
);
1713 error
= kern_path(pathname
, LOOKUP_FOLLOW
, &path
);
1715 return ERR_PTR(error
);
1717 inode
= d_backing_inode(path
.dentry
);
1719 if (!S_ISBLK(inode
->i_mode
))
1722 if (path
.mnt
->mnt_flags
& MNT_NODEV
)
1725 bdev
= bd_acquire(inode
);
1732 bdev
= ERR_PTR(error
);
1735 EXPORT_SYMBOL(lookup_bdev
);
1737 int __invalidate_device(struct block_device
*bdev
, bool kill_dirty
)
1739 struct super_block
*sb
= get_super(bdev
);
1744 * no need to lock the super, get_super holds the
1745 * read mutex so the filesystem cannot go away
1746 * under us (->put_super runs with the write lock
1749 shrink_dcache_sb(sb
);
1750 res
= invalidate_inodes(sb
, kill_dirty
);
1753 invalidate_bdev(bdev
);
1756 EXPORT_SYMBOL(__invalidate_device
);
1758 void iterate_bdevs(void (*func
)(struct block_device
*, void *), void *arg
)
1760 struct inode
*inode
, *old_inode
= NULL
;
1762 spin_lock(&inode_sb_list_lock
);
1763 list_for_each_entry(inode
, &blockdev_superblock
->s_inodes
, i_sb_list
) {
1764 struct address_space
*mapping
= inode
->i_mapping
;
1766 spin_lock(&inode
->i_lock
);
1767 if (inode
->i_state
& (I_FREEING
|I_WILL_FREE
|I_NEW
) ||
1768 mapping
->nrpages
== 0) {
1769 spin_unlock(&inode
->i_lock
);
1773 spin_unlock(&inode
->i_lock
);
1774 spin_unlock(&inode_sb_list_lock
);
1776 * We hold a reference to 'inode' so it couldn't have been
1777 * removed from s_inodes list while we dropped the
1778 * inode_sb_list_lock. We cannot iput the inode now as we can
1779 * be holding the last reference and we cannot iput it under
1780 * inode_sb_list_lock. So we keep the reference and iput it
1786 func(I_BDEV(inode
), arg
);
1788 spin_lock(&inode_sb_list_lock
);
1790 spin_unlock(&inode_sb_list_lock
);