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/module.h>
18 #include <linux/blkpg.h>
19 #include <linux/magic.h>
20 #include <linux/buffer_head.h>
21 #include <linux/swap.h>
22 #include <linux/pagevec.h>
23 #include <linux/writeback.h>
24 #include <linux/mpage.h>
25 #include <linux/mount.h>
26 #include <linux/uio.h>
27 #include <linux/namei.h>
28 #include <linux/log2.h>
29 #include <linux/cleancache.h>
30 #include <asm/uaccess.h>
34 struct block_device bdev
;
35 struct inode vfs_inode
;
38 static const struct address_space_operations def_blk_aops
;
40 static inline struct bdev_inode
*BDEV_I(struct inode
*inode
)
42 return container_of(inode
, struct bdev_inode
, vfs_inode
);
45 inline struct block_device
*I_BDEV(struct inode
*inode
)
47 return &BDEV_I(inode
)->bdev
;
49 EXPORT_SYMBOL(I_BDEV
);
52 * Move the inode from its current bdi to a new bdi. If the inode is dirty we
53 * need to move it onto the dirty list of @dst so that the inode is always on
56 static void bdev_inode_switch_bdi(struct inode
*inode
,
57 struct backing_dev_info
*dst
)
59 struct backing_dev_info
*old
= inode
->i_data
.backing_dev_info
;
61 if (unlikely(dst
== old
)) /* deadlock avoidance */
63 bdi_lock_two(&old
->wb
, &dst
->wb
);
64 spin_lock(&inode
->i_lock
);
65 inode
->i_data
.backing_dev_info
= dst
;
66 if (inode
->i_state
& I_DIRTY
)
67 list_move(&inode
->i_wb_list
, &dst
->wb
.b_dirty
);
68 spin_unlock(&inode
->i_lock
);
69 spin_unlock(&old
->wb
.list_lock
);
70 spin_unlock(&dst
->wb
.list_lock
);
73 sector_t
blkdev_max_block(struct block_device
*bdev
)
75 sector_t retval
= ~((sector_t
)0);
76 loff_t sz
= i_size_read(bdev
->bd_inode
);
79 unsigned int size
= block_size(bdev
);
80 unsigned int sizebits
= blksize_bits(size
);
81 retval
= (sz
>> sizebits
);
86 /* Kill _all_ buffers and pagecache , dirty or not.. */
87 void kill_bdev(struct block_device
*bdev
)
89 struct address_space
*mapping
= bdev
->bd_inode
->i_mapping
;
91 if (mapping
->nrpages
== 0)
95 truncate_inode_pages(mapping
, 0);
97 EXPORT_SYMBOL(kill_bdev
);
99 /* Invalidate clean unused buffers and pagecache. */
100 void invalidate_bdev(struct block_device
*bdev
)
102 struct address_space
*mapping
= bdev
->bd_inode
->i_mapping
;
104 if (mapping
->nrpages
== 0)
107 invalidate_bh_lrus();
108 lru_add_drain_all(); /* make sure all lru add caches are flushed */
109 invalidate_mapping_pages(mapping
, 0, -1);
110 /* 99% of the time, we don't need to flush the cleancache on the bdev.
111 * But, for the strange corners, lets be cautious
113 cleancache_invalidate_inode(mapping
);
115 EXPORT_SYMBOL(invalidate_bdev
);
117 int set_blocksize(struct block_device
*bdev
, int size
)
119 struct address_space
*mapping
;
121 /* Size must be a power of two, and between 512 and PAGE_SIZE */
122 if (size
> PAGE_SIZE
|| size
< 512 || !is_power_of_2(size
))
125 /* Size cannot be smaller than the size supported by the device */
126 if (size
< bdev_logical_block_size(bdev
))
129 /* Prevent starting I/O or mapping the device */
130 down_write(&bdev
->bd_block_size_semaphore
);
132 /* Check that the block device is not memory mapped */
133 mapping
= bdev
->bd_inode
->i_mapping
;
134 mutex_lock(&mapping
->i_mmap_mutex
);
135 if (!prio_tree_empty(&mapping
->i_mmap
) ||
136 !list_empty(&mapping
->i_mmap_nonlinear
)) {
137 mutex_unlock(&mapping
->i_mmap_mutex
);
138 up_write(&bdev
->bd_block_size_semaphore
);
141 mutex_unlock(&mapping
->i_mmap_mutex
);
143 /* Don't change the size if it is same as current */
144 if (bdev
->bd_block_size
!= size
) {
146 bdev
->bd_block_size
= size
;
147 bdev
->bd_inode
->i_blkbits
= blksize_bits(size
);
151 up_write(&bdev
->bd_block_size_semaphore
);
156 EXPORT_SYMBOL(set_blocksize
);
158 int sb_set_blocksize(struct super_block
*sb
, int size
)
160 if (set_blocksize(sb
->s_bdev
, size
))
162 /* If we get here, we know size is power of two
163 * and it's value is between 512 and PAGE_SIZE */
164 sb
->s_blocksize
= size
;
165 sb
->s_blocksize_bits
= blksize_bits(size
);
166 return sb
->s_blocksize
;
169 EXPORT_SYMBOL(sb_set_blocksize
);
171 int sb_min_blocksize(struct super_block
*sb
, int size
)
173 int minsize
= bdev_logical_block_size(sb
->s_bdev
);
176 return sb_set_blocksize(sb
, size
);
179 EXPORT_SYMBOL(sb_min_blocksize
);
182 blkdev_get_block(struct inode
*inode
, sector_t iblock
,
183 struct buffer_head
*bh
, int create
)
185 if (iblock
>= blkdev_max_block(I_BDEV(inode
))) {
190 * for reads, we're just trying to fill a partial page.
191 * return a hole, they will have to call get_block again
192 * before they can fill it, and they will get -EIO at that
197 bh
->b_bdev
= I_BDEV(inode
);
198 bh
->b_blocknr
= iblock
;
199 set_buffer_mapped(bh
);
204 blkdev_get_blocks(struct inode
*inode
, sector_t iblock
,
205 struct buffer_head
*bh
, int create
)
207 sector_t end_block
= blkdev_max_block(I_BDEV(inode
));
208 unsigned long max_blocks
= bh
->b_size
>> inode
->i_blkbits
;
210 if ((iblock
+ max_blocks
) > end_block
) {
211 max_blocks
= end_block
- iblock
;
212 if ((long)max_blocks
<= 0) {
214 return -EIO
; /* write fully beyond EOF */
216 * It is a read which is fully beyond EOF. We return
217 * a !buffer_mapped buffer
223 bh
->b_bdev
= I_BDEV(inode
);
224 bh
->b_blocknr
= iblock
;
225 bh
->b_size
= max_blocks
<< inode
->i_blkbits
;
227 set_buffer_mapped(bh
);
232 blkdev_direct_IO(int rw
, struct kiocb
*iocb
, const struct iovec
*iov
,
233 loff_t offset
, unsigned long nr_segs
)
235 struct file
*file
= iocb
->ki_filp
;
236 struct inode
*inode
= file
->f_mapping
->host
;
238 return __blockdev_direct_IO(rw
, iocb
, inode
, I_BDEV(inode
), iov
, offset
,
239 nr_segs
, blkdev_get_blocks
, NULL
, NULL
, 0);
242 int __sync_blockdev(struct block_device
*bdev
, int wait
)
247 return filemap_flush(bdev
->bd_inode
->i_mapping
);
248 return filemap_write_and_wait(bdev
->bd_inode
->i_mapping
);
252 * Write out and wait upon all the dirty data associated with a block
253 * device via its mapping. Does not take the superblock lock.
255 int sync_blockdev(struct block_device
*bdev
)
257 return __sync_blockdev(bdev
, 1);
259 EXPORT_SYMBOL(sync_blockdev
);
262 * Write out and wait upon all dirty data associated with this
263 * device. Filesystem data as well as the underlying block
264 * device. Takes the superblock lock.
266 int fsync_bdev(struct block_device
*bdev
)
268 struct super_block
*sb
= get_super(bdev
);
270 int res
= sync_filesystem(sb
);
274 return sync_blockdev(bdev
);
276 EXPORT_SYMBOL(fsync_bdev
);
279 * freeze_bdev -- lock a filesystem and force it into a consistent state
280 * @bdev: blockdevice to lock
282 * If a superblock is found on this device, we take the s_umount semaphore
283 * on it to make sure nobody unmounts until the snapshot creation is done.
284 * The reference counter (bd_fsfreeze_count) guarantees that only the last
285 * unfreeze process can unfreeze the frozen filesystem actually when multiple
286 * freeze requests arrive simultaneously. It counts up in freeze_bdev() and
287 * count down in thaw_bdev(). When it becomes 0, thaw_bdev() will unfreeze
290 struct super_block
*freeze_bdev(struct block_device
*bdev
)
292 struct super_block
*sb
;
295 mutex_lock(&bdev
->bd_fsfreeze_mutex
);
296 if (++bdev
->bd_fsfreeze_count
> 1) {
298 * We don't even need to grab a reference - the first call
299 * to freeze_bdev grab an active reference and only the last
300 * thaw_bdev drops it.
302 sb
= get_super(bdev
);
304 mutex_unlock(&bdev
->bd_fsfreeze_mutex
);
308 sb
= get_active_super(bdev
);
311 error
= freeze_super(sb
);
313 deactivate_super(sb
);
314 bdev
->bd_fsfreeze_count
--;
315 mutex_unlock(&bdev
->bd_fsfreeze_mutex
);
316 return ERR_PTR(error
);
318 deactivate_super(sb
);
321 mutex_unlock(&bdev
->bd_fsfreeze_mutex
);
322 return sb
; /* thaw_bdev releases s->s_umount */
324 EXPORT_SYMBOL(freeze_bdev
);
327 * thaw_bdev -- unlock filesystem
328 * @bdev: blockdevice to unlock
329 * @sb: associated superblock
331 * Unlocks the filesystem and marks it writeable again after freeze_bdev().
333 int thaw_bdev(struct block_device
*bdev
, struct super_block
*sb
)
337 mutex_lock(&bdev
->bd_fsfreeze_mutex
);
338 if (!bdev
->bd_fsfreeze_count
)
342 if (--bdev
->bd_fsfreeze_count
> 0)
348 error
= thaw_super(sb
);
350 bdev
->bd_fsfreeze_count
++;
351 mutex_unlock(&bdev
->bd_fsfreeze_mutex
);
355 mutex_unlock(&bdev
->bd_fsfreeze_mutex
);
358 EXPORT_SYMBOL(thaw_bdev
);
360 static int blkdev_writepage(struct page
*page
, struct writeback_control
*wbc
)
362 return block_write_full_page(page
, blkdev_get_block
, wbc
);
365 static int blkdev_readpage(struct file
* file
, struct page
* page
)
367 return block_read_full_page(page
, blkdev_get_block
);
370 static int blkdev_write_begin(struct file
*file
, struct address_space
*mapping
,
371 loff_t pos
, unsigned len
, unsigned flags
,
372 struct page
**pagep
, void **fsdata
)
374 return block_write_begin(mapping
, pos
, len
, flags
, pagep
,
378 static int blkdev_write_end(struct file
*file
, struct address_space
*mapping
,
379 loff_t pos
, unsigned len
, unsigned copied
,
380 struct page
*page
, void *fsdata
)
383 ret
= block_write_end(file
, mapping
, pos
, len
, copied
, page
, fsdata
);
386 page_cache_release(page
);
393 * for a block special file file->f_path.dentry->d_inode->i_size is zero
394 * so we compute the size by hand (just as in block_read/write above)
396 static loff_t
block_llseek(struct file
*file
, loff_t offset
, int origin
)
398 struct inode
*bd_inode
= file
->f_mapping
->host
;
402 mutex_lock(&bd_inode
->i_mutex
);
403 size
= i_size_read(bd_inode
);
411 offset
+= file
->f_pos
;
417 if (offset
>= 0 && offset
<= size
) {
418 if (offset
!= file
->f_pos
) {
419 file
->f_pos
= offset
;
424 mutex_unlock(&bd_inode
->i_mutex
);
428 int blkdev_fsync(struct file
*filp
, loff_t start
, loff_t end
, int datasync
)
430 struct inode
*bd_inode
= filp
->f_mapping
->host
;
431 struct block_device
*bdev
= I_BDEV(bd_inode
);
434 error
= filemap_write_and_wait_range(filp
->f_mapping
, start
, end
);
439 * There is no need to serialise calls to blkdev_issue_flush with
440 * i_mutex and doing so causes performance issues with concurrent
441 * O_SYNC writers to a block device.
443 error
= blkdev_issue_flush(bdev
, GFP_KERNEL
, NULL
);
444 if (error
== -EOPNOTSUPP
)
449 EXPORT_SYMBOL(blkdev_fsync
);
455 static __cacheline_aligned_in_smp
DEFINE_SPINLOCK(bdev_lock
);
456 static struct kmem_cache
* bdev_cachep __read_mostly
;
458 static struct inode
*bdev_alloc_inode(struct super_block
*sb
)
460 struct bdev_inode
*ei
= kmem_cache_alloc(bdev_cachep
, GFP_KERNEL
);
463 return &ei
->vfs_inode
;
466 static void bdev_i_callback(struct rcu_head
*head
)
468 struct inode
*inode
= container_of(head
, struct inode
, i_rcu
);
469 struct bdev_inode
*bdi
= BDEV_I(inode
);
471 kmem_cache_free(bdev_cachep
, bdi
);
474 static void bdev_destroy_inode(struct inode
*inode
)
476 call_rcu(&inode
->i_rcu
, bdev_i_callback
);
479 static void init_once(void *foo
)
481 struct bdev_inode
*ei
= (struct bdev_inode
*) foo
;
482 struct block_device
*bdev
= &ei
->bdev
;
484 memset(bdev
, 0, sizeof(*bdev
));
485 mutex_init(&bdev
->bd_mutex
);
486 INIT_LIST_HEAD(&bdev
->bd_inodes
);
487 INIT_LIST_HEAD(&bdev
->bd_list
);
489 INIT_LIST_HEAD(&bdev
->bd_holder_disks
);
491 inode_init_once(&ei
->vfs_inode
);
492 /* Initialize mutex for freeze. */
493 mutex_init(&bdev
->bd_fsfreeze_mutex
);
494 init_rwsem(&bdev
->bd_block_size_semaphore
);
497 static inline void __bd_forget(struct inode
*inode
)
499 list_del_init(&inode
->i_devices
);
500 inode
->i_bdev
= NULL
;
501 inode
->i_mapping
= &inode
->i_data
;
504 static void bdev_evict_inode(struct inode
*inode
)
506 struct block_device
*bdev
= &BDEV_I(inode
)->bdev
;
508 truncate_inode_pages(&inode
->i_data
, 0);
509 invalidate_inode_buffers(inode
); /* is it needed here? */
511 spin_lock(&bdev_lock
);
512 while ( (p
= bdev
->bd_inodes
.next
) != &bdev
->bd_inodes
) {
513 __bd_forget(list_entry(p
, struct inode
, i_devices
));
515 list_del_init(&bdev
->bd_list
);
516 spin_unlock(&bdev_lock
);
519 static const struct super_operations bdev_sops
= {
520 .statfs
= simple_statfs
,
521 .alloc_inode
= bdev_alloc_inode
,
522 .destroy_inode
= bdev_destroy_inode
,
523 .drop_inode
= generic_delete_inode
,
524 .evict_inode
= bdev_evict_inode
,
527 static struct dentry
*bd_mount(struct file_system_type
*fs_type
,
528 int flags
, const char *dev_name
, void *data
)
530 return mount_pseudo(fs_type
, "bdev:", &bdev_sops
, NULL
, BDEVFS_MAGIC
);
533 static struct file_system_type bd_type
= {
536 .kill_sb
= kill_anon_super
,
539 static struct super_block
*blockdev_superblock __read_mostly
;
541 void __init
bdev_cache_init(void)
544 static struct vfsmount
*bd_mnt
;
546 bdev_cachep
= kmem_cache_create("bdev_cache", sizeof(struct bdev_inode
),
547 0, (SLAB_HWCACHE_ALIGN
|SLAB_RECLAIM_ACCOUNT
|
548 SLAB_MEM_SPREAD
|SLAB_PANIC
),
550 err
= register_filesystem(&bd_type
);
552 panic("Cannot register bdev pseudo-fs");
553 bd_mnt
= kern_mount(&bd_type
);
555 panic("Cannot create bdev pseudo-fs");
556 blockdev_superblock
= bd_mnt
->mnt_sb
; /* For writeback */
560 * Most likely _very_ bad one - but then it's hardly critical for small
561 * /dev and can be fixed when somebody will need really large one.
562 * Keep in mind that it will be fed through icache hash function too.
564 static inline unsigned long hash(dev_t dev
)
566 return MAJOR(dev
)+MINOR(dev
);
569 static int bdev_test(struct inode
*inode
, void *data
)
571 return BDEV_I(inode
)->bdev
.bd_dev
== *(dev_t
*)data
;
574 static int bdev_set(struct inode
*inode
, void *data
)
576 BDEV_I(inode
)->bdev
.bd_dev
= *(dev_t
*)data
;
580 static LIST_HEAD(all_bdevs
);
582 struct block_device
*bdget(dev_t dev
)
584 struct block_device
*bdev
;
587 inode
= iget5_locked(blockdev_superblock
, hash(dev
),
588 bdev_test
, bdev_set
, &dev
);
593 bdev
= &BDEV_I(inode
)->bdev
;
595 if (inode
->i_state
& I_NEW
) {
596 bdev
->bd_contains
= NULL
;
597 bdev
->bd_super
= NULL
;
598 bdev
->bd_inode
= inode
;
599 bdev
->bd_block_size
= (1 << inode
->i_blkbits
);
600 bdev
->bd_part_count
= 0;
601 bdev
->bd_invalidated
= 0;
602 inode
->i_mode
= S_IFBLK
;
604 inode
->i_bdev
= bdev
;
605 inode
->i_data
.a_ops
= &def_blk_aops
;
606 mapping_set_gfp_mask(&inode
->i_data
, GFP_USER
);
607 inode
->i_data
.backing_dev_info
= &default_backing_dev_info
;
608 spin_lock(&bdev_lock
);
609 list_add(&bdev
->bd_list
, &all_bdevs
);
610 spin_unlock(&bdev_lock
);
611 unlock_new_inode(inode
);
616 EXPORT_SYMBOL(bdget
);
619 * bdgrab -- Grab a reference to an already referenced block device
620 * @bdev: Block device to grab a reference to.
622 struct block_device
*bdgrab(struct block_device
*bdev
)
624 ihold(bdev
->bd_inode
);
628 long nr_blockdev_pages(void)
630 struct block_device
*bdev
;
632 spin_lock(&bdev_lock
);
633 list_for_each_entry(bdev
, &all_bdevs
, bd_list
) {
634 ret
+= bdev
->bd_inode
->i_mapping
->nrpages
;
636 spin_unlock(&bdev_lock
);
640 void bdput(struct block_device
*bdev
)
642 iput(bdev
->bd_inode
);
645 EXPORT_SYMBOL(bdput
);
647 static struct block_device
*bd_acquire(struct inode
*inode
)
649 struct block_device
*bdev
;
651 spin_lock(&bdev_lock
);
652 bdev
= inode
->i_bdev
;
654 ihold(bdev
->bd_inode
);
655 spin_unlock(&bdev_lock
);
658 spin_unlock(&bdev_lock
);
660 bdev
= bdget(inode
->i_rdev
);
662 spin_lock(&bdev_lock
);
663 if (!inode
->i_bdev
) {
665 * We take an additional reference to bd_inode,
666 * and it's released in clear_inode() of inode.
667 * So, we can access it via ->i_mapping always
670 ihold(bdev
->bd_inode
);
671 inode
->i_bdev
= bdev
;
672 inode
->i_mapping
= bdev
->bd_inode
->i_mapping
;
673 list_add(&inode
->i_devices
, &bdev
->bd_inodes
);
675 spin_unlock(&bdev_lock
);
680 static inline int sb_is_blkdev_sb(struct super_block
*sb
)
682 return sb
== blockdev_superblock
;
685 /* Call when you free inode */
687 void bd_forget(struct inode
*inode
)
689 struct block_device
*bdev
= NULL
;
691 spin_lock(&bdev_lock
);
693 if (!sb_is_blkdev_sb(inode
->i_sb
))
694 bdev
= inode
->i_bdev
;
697 spin_unlock(&bdev_lock
);
700 iput(bdev
->bd_inode
);
704 * bd_may_claim - test whether a block device can be claimed
705 * @bdev: block device of interest
706 * @whole: whole block device containing @bdev, may equal @bdev
707 * @holder: holder trying to claim @bdev
709 * Test whether @bdev can be claimed by @holder.
712 * spin_lock(&bdev_lock).
715 * %true if @bdev can be claimed, %false otherwise.
717 static bool bd_may_claim(struct block_device
*bdev
, struct block_device
*whole
,
720 if (bdev
->bd_holder
== holder
)
721 return true; /* already a holder */
722 else if (bdev
->bd_holder
!= NULL
)
723 return false; /* held by someone else */
724 else if (bdev
->bd_contains
== bdev
)
725 return true; /* is a whole device which isn't held */
727 else if (whole
->bd_holder
== bd_may_claim
)
728 return true; /* is a partition of a device that is being partitioned */
729 else if (whole
->bd_holder
!= NULL
)
730 return false; /* is a partition of a held device */
732 return true; /* is a partition of an un-held device */
736 * bd_prepare_to_claim - prepare to claim a block device
737 * @bdev: block device of interest
738 * @whole: the whole device containing @bdev, may equal @bdev
739 * @holder: holder trying to claim @bdev
741 * Prepare to claim @bdev. This function fails if @bdev is already
742 * claimed by another holder and waits if another claiming is in
743 * progress. This function doesn't actually claim. On successful
744 * return, the caller has ownership of bd_claiming and bd_holder[s].
747 * spin_lock(&bdev_lock). Might release bdev_lock, sleep and regrab
751 * 0 if @bdev can be claimed, -EBUSY otherwise.
753 static int bd_prepare_to_claim(struct block_device
*bdev
,
754 struct block_device
*whole
, void *holder
)
757 /* if someone else claimed, fail */
758 if (!bd_may_claim(bdev
, whole
, holder
))
761 /* if claiming is already in progress, wait for it to finish */
762 if (whole
->bd_claiming
) {
763 wait_queue_head_t
*wq
= bit_waitqueue(&whole
->bd_claiming
, 0);
766 prepare_to_wait(wq
, &wait
, TASK_UNINTERRUPTIBLE
);
767 spin_unlock(&bdev_lock
);
769 finish_wait(wq
, &wait
);
770 spin_lock(&bdev_lock
);
779 * bd_start_claiming - start claiming a block device
780 * @bdev: block device of interest
781 * @holder: holder trying to claim @bdev
783 * @bdev is about to be opened exclusively. Check @bdev can be opened
784 * exclusively and mark that an exclusive open is in progress. Each
785 * successful call to this function must be matched with a call to
786 * either bd_finish_claiming() or bd_abort_claiming() (which do not
789 * This function is used to gain exclusive access to the block device
790 * without actually causing other exclusive open attempts to fail. It
791 * should be used when the open sequence itself requires exclusive
792 * access but may subsequently fail.
798 * Pointer to the block device containing @bdev on success, ERR_PTR()
801 static struct block_device
*bd_start_claiming(struct block_device
*bdev
,
804 struct gendisk
*disk
;
805 struct block_device
*whole
;
811 * @bdev might not have been initialized properly yet, look up
812 * and grab the outer block device the hard way.
814 disk
= get_gendisk(bdev
->bd_dev
, &partno
);
816 return ERR_PTR(-ENXIO
);
819 * Normally, @bdev should equal what's returned from bdget_disk()
820 * if partno is 0; however, some drivers (floppy) use multiple
821 * bdev's for the same physical device and @bdev may be one of the
822 * aliases. Keep @bdev if partno is 0. This means claimer
823 * tracking is broken for those devices but it has always been that
827 whole
= bdget_disk(disk
, 0);
829 whole
= bdgrab(bdev
);
831 module_put(disk
->fops
->owner
);
834 return ERR_PTR(-ENOMEM
);
836 /* prepare to claim, if successful, mark claiming in progress */
837 spin_lock(&bdev_lock
);
839 err
= bd_prepare_to_claim(bdev
, whole
, holder
);
841 whole
->bd_claiming
= holder
;
842 spin_unlock(&bdev_lock
);
845 spin_unlock(&bdev_lock
);
852 struct bd_holder_disk
{
853 struct list_head list
;
854 struct gendisk
*disk
;
858 static struct bd_holder_disk
*bd_find_holder_disk(struct block_device
*bdev
,
859 struct gendisk
*disk
)
861 struct bd_holder_disk
*holder
;
863 list_for_each_entry(holder
, &bdev
->bd_holder_disks
, list
)
864 if (holder
->disk
== disk
)
869 static int add_symlink(struct kobject
*from
, struct kobject
*to
)
871 return sysfs_create_link(from
, to
, kobject_name(to
));
874 static void del_symlink(struct kobject
*from
, struct kobject
*to
)
876 sysfs_remove_link(from
, kobject_name(to
));
880 * bd_link_disk_holder - create symlinks between holding disk and slave bdev
881 * @bdev: the claimed slave bdev
882 * @disk: the holding disk
884 * DON'T USE THIS UNLESS YOU'RE ALREADY USING IT.
886 * This functions creates the following sysfs symlinks.
888 * - from "slaves" directory of the holder @disk to the claimed @bdev
889 * - from "holders" directory of the @bdev to the holder @disk
891 * For example, if /dev/dm-0 maps to /dev/sda and disk for dm-0 is
892 * passed to bd_link_disk_holder(), then:
894 * /sys/block/dm-0/slaves/sda --> /sys/block/sda
895 * /sys/block/sda/holders/dm-0 --> /sys/block/dm-0
897 * The caller must have claimed @bdev before calling this function and
898 * ensure that both @bdev and @disk are valid during the creation and
899 * lifetime of these symlinks.
905 * 0 on success, -errno on failure.
907 int bd_link_disk_holder(struct block_device
*bdev
, struct gendisk
*disk
)
909 struct bd_holder_disk
*holder
;
912 mutex_lock(&bdev
->bd_mutex
);
914 WARN_ON_ONCE(!bdev
->bd_holder
);
916 /* FIXME: remove the following once add_disk() handles errors */
917 if (WARN_ON(!disk
->slave_dir
|| !bdev
->bd_part
->holder_dir
))
920 holder
= bd_find_holder_disk(bdev
, disk
);
926 holder
= kzalloc(sizeof(*holder
), GFP_KERNEL
);
932 INIT_LIST_HEAD(&holder
->list
);
936 ret
= add_symlink(disk
->slave_dir
, &part_to_dev(bdev
->bd_part
)->kobj
);
940 ret
= add_symlink(bdev
->bd_part
->holder_dir
, &disk_to_dev(disk
)->kobj
);
944 * bdev could be deleted beneath us which would implicitly destroy
945 * the holder directory. Hold on to it.
947 kobject_get(bdev
->bd_part
->holder_dir
);
949 list_add(&holder
->list
, &bdev
->bd_holder_disks
);
953 del_symlink(disk
->slave_dir
, &part_to_dev(bdev
->bd_part
)->kobj
);
957 mutex_unlock(&bdev
->bd_mutex
);
960 EXPORT_SYMBOL_GPL(bd_link_disk_holder
);
963 * bd_unlink_disk_holder - destroy symlinks created by bd_link_disk_holder()
964 * @bdev: the calimed slave bdev
965 * @disk: the holding disk
967 * DON'T USE THIS UNLESS YOU'RE ALREADY USING IT.
972 void bd_unlink_disk_holder(struct block_device
*bdev
, struct gendisk
*disk
)
974 struct bd_holder_disk
*holder
;
976 mutex_lock(&bdev
->bd_mutex
);
978 holder
= bd_find_holder_disk(bdev
, disk
);
980 if (!WARN_ON_ONCE(holder
== NULL
) && !--holder
->refcnt
) {
981 del_symlink(disk
->slave_dir
, &part_to_dev(bdev
->bd_part
)->kobj
);
982 del_symlink(bdev
->bd_part
->holder_dir
,
983 &disk_to_dev(disk
)->kobj
);
984 kobject_put(bdev
->bd_part
->holder_dir
);
985 list_del_init(&holder
->list
);
989 mutex_unlock(&bdev
->bd_mutex
);
991 EXPORT_SYMBOL_GPL(bd_unlink_disk_holder
);
995 * flush_disk - invalidates all buffer-cache entries on a disk
997 * @bdev: struct block device to be flushed
998 * @kill_dirty: flag to guide handling of dirty inodes
1000 * Invalidates all buffer-cache entries on a disk. It should be called
1001 * when a disk has been changed -- either by a media change or online
1004 static void flush_disk(struct block_device
*bdev
, bool kill_dirty
)
1006 if (__invalidate_device(bdev
, kill_dirty
)) {
1007 char name
[BDEVNAME_SIZE
] = "";
1010 disk_name(bdev
->bd_disk
, 0, name
);
1011 printk(KERN_WARNING
"VFS: busy inodes on changed media or "
1012 "resized disk %s\n", name
);
1017 if (disk_part_scan_enabled(bdev
->bd_disk
))
1018 bdev
->bd_invalidated
= 1;
1022 * check_disk_size_change - checks for disk size change and adjusts bdev size.
1023 * @disk: struct gendisk to check
1024 * @bdev: struct bdev to adjust.
1026 * This routine checks to see if the bdev size does not match the disk size
1027 * and adjusts it if it differs.
1029 void check_disk_size_change(struct gendisk
*disk
, struct block_device
*bdev
)
1031 loff_t disk_size
, bdev_size
;
1033 disk_size
= (loff_t
)get_capacity(disk
) << 9;
1034 bdev_size
= i_size_read(bdev
->bd_inode
);
1035 if (disk_size
!= bdev_size
) {
1036 char name
[BDEVNAME_SIZE
];
1038 disk_name(disk
, 0, name
);
1040 "%s: detected capacity change from %lld to %lld\n",
1041 name
, bdev_size
, disk_size
);
1042 i_size_write(bdev
->bd_inode
, disk_size
);
1043 flush_disk(bdev
, false);
1046 EXPORT_SYMBOL(check_disk_size_change
);
1049 * revalidate_disk - wrapper for lower-level driver's revalidate_disk call-back
1050 * @disk: struct gendisk to be revalidated
1052 * This routine is a wrapper for lower-level driver's revalidate_disk
1053 * call-backs. It is used to do common pre and post operations needed
1054 * for all revalidate_disk operations.
1056 int revalidate_disk(struct gendisk
*disk
)
1058 struct block_device
*bdev
;
1061 if (disk
->fops
->revalidate_disk
)
1062 ret
= disk
->fops
->revalidate_disk(disk
);
1064 bdev
= bdget_disk(disk
, 0);
1068 mutex_lock(&bdev
->bd_mutex
);
1069 check_disk_size_change(disk
, bdev
);
1070 mutex_unlock(&bdev
->bd_mutex
);
1074 EXPORT_SYMBOL(revalidate_disk
);
1077 * This routine checks whether a removable media has been changed,
1078 * and invalidates all buffer-cache-entries in that case. This
1079 * is a relatively slow routine, so we have to try to minimize using
1080 * it. Thus it is called only upon a 'mount' or 'open'. This
1081 * is the best way of combining speed and utility, I think.
1082 * People changing diskettes in the middle of an operation deserve
1085 int check_disk_change(struct block_device
*bdev
)
1087 struct gendisk
*disk
= bdev
->bd_disk
;
1088 const struct block_device_operations
*bdops
= disk
->fops
;
1089 unsigned int events
;
1091 events
= disk_clear_events(disk
, DISK_EVENT_MEDIA_CHANGE
|
1092 DISK_EVENT_EJECT_REQUEST
);
1093 if (!(events
& DISK_EVENT_MEDIA_CHANGE
))
1096 flush_disk(bdev
, true);
1097 if (bdops
->revalidate_disk
)
1098 bdops
->revalidate_disk(bdev
->bd_disk
);
1102 EXPORT_SYMBOL(check_disk_change
);
1104 void bd_set_size(struct block_device
*bdev
, loff_t size
)
1106 unsigned bsize
= bdev_logical_block_size(bdev
);
1108 bdev
->bd_inode
->i_size
= size
;
1109 while (bsize
< PAGE_CACHE_SIZE
) {
1114 bdev
->bd_block_size
= bsize
;
1115 bdev
->bd_inode
->i_blkbits
= blksize_bits(bsize
);
1117 EXPORT_SYMBOL(bd_set_size
);
1119 static int __blkdev_put(struct block_device
*bdev
, fmode_t mode
, int for_part
);
1124 * mutex_lock(part->bd_mutex)
1125 * mutex_lock_nested(whole->bd_mutex, 1)
1128 static int __blkdev_get(struct block_device
*bdev
, fmode_t mode
, int for_part
)
1130 struct gendisk
*disk
;
1131 struct module
*owner
;
1136 if (mode
& FMODE_READ
)
1138 if (mode
& FMODE_WRITE
)
1141 * hooks: /n/, see "layering violations".
1144 ret
= devcgroup_inode_permission(bdev
->bd_inode
, perm
);
1154 disk
= get_gendisk(bdev
->bd_dev
, &partno
);
1157 owner
= disk
->fops
->owner
;
1159 disk_block_events(disk
);
1160 mutex_lock_nested(&bdev
->bd_mutex
, for_part
);
1161 if (!bdev
->bd_openers
) {
1162 bdev
->bd_disk
= disk
;
1163 bdev
->bd_queue
= disk
->queue
;
1164 bdev
->bd_contains
= bdev
;
1166 struct backing_dev_info
*bdi
;
1169 bdev
->bd_part
= disk_get_part(disk
, partno
);
1174 if (disk
->fops
->open
) {
1175 ret
= disk
->fops
->open(bdev
, mode
);
1176 if (ret
== -ERESTARTSYS
) {
1177 /* Lost a race with 'disk' being
1178 * deleted, try again.
1181 disk_put_part(bdev
->bd_part
);
1182 bdev
->bd_part
= NULL
;
1183 bdev
->bd_disk
= NULL
;
1184 bdev
->bd_queue
= NULL
;
1185 mutex_unlock(&bdev
->bd_mutex
);
1186 disk_unblock_events(disk
);
1193 if (!ret
&& !bdev
->bd_openers
) {
1194 bd_set_size(bdev
,(loff_t
)get_capacity(disk
)<<9);
1195 bdi
= blk_get_backing_dev_info(bdev
);
1197 bdi
= &default_backing_dev_info
;
1198 bdev_inode_switch_bdi(bdev
->bd_inode
, bdi
);
1202 * If the device is invalidated, rescan partition
1203 * if open succeeded or failed with -ENOMEDIUM.
1204 * The latter is necessary to prevent ghost
1205 * partitions on a removed medium.
1207 if (bdev
->bd_invalidated
) {
1209 rescan_partitions(disk
, bdev
);
1210 else if (ret
== -ENOMEDIUM
)
1211 invalidate_partitions(disk
, bdev
);
1216 struct block_device
*whole
;
1217 whole
= bdget_disk(disk
, 0);
1222 ret
= __blkdev_get(whole
, mode
, 1);
1225 bdev
->bd_contains
= whole
;
1226 bdev_inode_switch_bdi(bdev
->bd_inode
,
1227 whole
->bd_inode
->i_data
.backing_dev_info
);
1228 bdev
->bd_part
= disk_get_part(disk
, partno
);
1229 if (!(disk
->flags
& GENHD_FL_UP
) ||
1230 !bdev
->bd_part
|| !bdev
->bd_part
->nr_sects
) {
1234 bd_set_size(bdev
, (loff_t
)bdev
->bd_part
->nr_sects
<< 9);
1237 if (bdev
->bd_contains
== bdev
) {
1239 if (bdev
->bd_disk
->fops
->open
)
1240 ret
= bdev
->bd_disk
->fops
->open(bdev
, mode
);
1241 /* the same as first opener case, read comment there */
1242 if (bdev
->bd_invalidated
) {
1244 rescan_partitions(bdev
->bd_disk
, bdev
);
1245 else if (ret
== -ENOMEDIUM
)
1246 invalidate_partitions(bdev
->bd_disk
, bdev
);
1249 goto out_unlock_bdev
;
1251 /* only one opener holds refs to the module and disk */
1257 bdev
->bd_part_count
++;
1258 mutex_unlock(&bdev
->bd_mutex
);
1259 disk_unblock_events(disk
);
1263 disk_put_part(bdev
->bd_part
);
1264 bdev
->bd_disk
= NULL
;
1265 bdev
->bd_part
= NULL
;
1266 bdev
->bd_queue
= NULL
;
1267 bdev_inode_switch_bdi(bdev
->bd_inode
, &default_backing_dev_info
);
1268 if (bdev
!= bdev
->bd_contains
)
1269 __blkdev_put(bdev
->bd_contains
, mode
, 1);
1270 bdev
->bd_contains
= NULL
;
1272 mutex_unlock(&bdev
->bd_mutex
);
1273 disk_unblock_events(disk
);
1283 * blkdev_get - open a block device
1284 * @bdev: block_device to open
1285 * @mode: FMODE_* mask
1286 * @holder: exclusive holder identifier
1288 * Open @bdev with @mode. If @mode includes %FMODE_EXCL, @bdev is
1289 * open with exclusive access. Specifying %FMODE_EXCL with %NULL
1290 * @holder is invalid. Exclusive opens may nest for the same @holder.
1292 * On success, the reference count of @bdev is unchanged. On failure,
1299 * 0 on success, -errno on failure.
1301 int blkdev_get(struct block_device
*bdev
, fmode_t mode
, void *holder
)
1303 struct block_device
*whole
= NULL
;
1306 WARN_ON_ONCE((mode
& FMODE_EXCL
) && !holder
);
1308 if ((mode
& FMODE_EXCL
) && holder
) {
1309 whole
= bd_start_claiming(bdev
, holder
);
1310 if (IS_ERR(whole
)) {
1312 return PTR_ERR(whole
);
1316 res
= __blkdev_get(bdev
, mode
, 0);
1319 struct gendisk
*disk
= whole
->bd_disk
;
1321 /* finish claiming */
1322 mutex_lock(&bdev
->bd_mutex
);
1323 spin_lock(&bdev_lock
);
1326 BUG_ON(!bd_may_claim(bdev
, whole
, holder
));
1328 * Note that for a whole device bd_holders
1329 * will be incremented twice, and bd_holder
1330 * will be set to bd_may_claim before being
1333 whole
->bd_holders
++;
1334 whole
->bd_holder
= bd_may_claim
;
1336 bdev
->bd_holder
= holder
;
1339 /* tell others that we're done */
1340 BUG_ON(whole
->bd_claiming
!= holder
);
1341 whole
->bd_claiming
= NULL
;
1342 wake_up_bit(&whole
->bd_claiming
, 0);
1344 spin_unlock(&bdev_lock
);
1347 * Block event polling for write claims if requested. Any
1348 * write holder makes the write_holder state stick until
1349 * all are released. This is good enough and tracking
1350 * individual writeable reference is too fragile given the
1351 * way @mode is used in blkdev_get/put().
1353 if (!res
&& (mode
& FMODE_WRITE
) && !bdev
->bd_write_holder
&&
1354 (disk
->flags
& GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE
)) {
1355 bdev
->bd_write_holder
= true;
1356 disk_block_events(disk
);
1359 mutex_unlock(&bdev
->bd_mutex
);
1365 EXPORT_SYMBOL(blkdev_get
);
1368 * blkdev_get_by_path - open a block device by name
1369 * @path: path to the block device to open
1370 * @mode: FMODE_* mask
1371 * @holder: exclusive holder identifier
1373 * Open the blockdevice described by the device file at @path. @mode
1374 * and @holder are identical to blkdev_get().
1376 * On success, the returned block_device has reference count of one.
1382 * Pointer to block_device on success, ERR_PTR(-errno) on failure.
1384 struct block_device
*blkdev_get_by_path(const char *path
, fmode_t mode
,
1387 struct block_device
*bdev
;
1390 bdev
= lookup_bdev(path
);
1394 err
= blkdev_get(bdev
, mode
, holder
);
1396 return ERR_PTR(err
);
1398 if ((mode
& FMODE_WRITE
) && bdev_read_only(bdev
)) {
1399 blkdev_put(bdev
, mode
);
1400 return ERR_PTR(-EACCES
);
1405 EXPORT_SYMBOL(blkdev_get_by_path
);
1408 * blkdev_get_by_dev - open a block device by device number
1409 * @dev: device number of block device to open
1410 * @mode: FMODE_* mask
1411 * @holder: exclusive holder identifier
1413 * Open the blockdevice described by device number @dev. @mode and
1414 * @holder are identical to blkdev_get().
1416 * Use it ONLY if you really do not have anything better - i.e. when
1417 * you are behind a truly sucky interface and all you are given is a
1418 * device number. _Never_ to be used for internal purposes. If you
1419 * ever need it - reconsider your API.
1421 * On success, the returned block_device has reference count of one.
1427 * Pointer to block_device on success, ERR_PTR(-errno) on failure.
1429 struct block_device
*blkdev_get_by_dev(dev_t dev
, fmode_t mode
, void *holder
)
1431 struct block_device
*bdev
;
1436 return ERR_PTR(-ENOMEM
);
1438 err
= blkdev_get(bdev
, mode
, holder
);
1440 return ERR_PTR(err
);
1444 EXPORT_SYMBOL(blkdev_get_by_dev
);
1446 static int blkdev_open(struct inode
* inode
, struct file
* filp
)
1448 struct block_device
*bdev
;
1451 * Preserve backwards compatibility and allow large file access
1452 * even if userspace doesn't ask for it explicitly. Some mkfs
1453 * binary needs it. We might want to drop this workaround
1454 * during an unstable branch.
1456 filp
->f_flags
|= O_LARGEFILE
;
1458 if (filp
->f_flags
& O_NDELAY
)
1459 filp
->f_mode
|= FMODE_NDELAY
;
1460 if (filp
->f_flags
& O_EXCL
)
1461 filp
->f_mode
|= FMODE_EXCL
;
1462 if ((filp
->f_flags
& O_ACCMODE
) == 3)
1463 filp
->f_mode
|= FMODE_WRITE_IOCTL
;
1465 bdev
= bd_acquire(inode
);
1469 filp
->f_mapping
= bdev
->bd_inode
->i_mapping
;
1471 return blkdev_get(bdev
, filp
->f_mode
, filp
);
1474 static int __blkdev_put(struct block_device
*bdev
, fmode_t mode
, int for_part
)
1477 struct gendisk
*disk
= bdev
->bd_disk
;
1478 struct block_device
*victim
= NULL
;
1480 mutex_lock_nested(&bdev
->bd_mutex
, for_part
);
1482 bdev
->bd_part_count
--;
1484 if (!--bdev
->bd_openers
) {
1485 WARN_ON_ONCE(bdev
->bd_holders
);
1486 sync_blockdev(bdev
);
1488 /* ->release can cause the old bdi to disappear,
1489 * so must switch it out first
1491 bdev_inode_switch_bdi(bdev
->bd_inode
,
1492 &default_backing_dev_info
);
1494 if (bdev
->bd_contains
== bdev
) {
1495 if (disk
->fops
->release
)
1496 ret
= disk
->fops
->release(disk
, mode
);
1498 if (!bdev
->bd_openers
) {
1499 struct module
*owner
= disk
->fops
->owner
;
1501 disk_put_part(bdev
->bd_part
);
1502 bdev
->bd_part
= NULL
;
1503 bdev
->bd_disk
= NULL
;
1504 if (bdev
!= bdev
->bd_contains
)
1505 victim
= bdev
->bd_contains
;
1506 bdev
->bd_contains
= NULL
;
1511 mutex_unlock(&bdev
->bd_mutex
);
1514 __blkdev_put(victim
, mode
, 1);
1518 int blkdev_put(struct block_device
*bdev
, fmode_t mode
)
1520 mutex_lock(&bdev
->bd_mutex
);
1522 if (mode
& FMODE_EXCL
) {
1526 * Release a claim on the device. The holder fields
1527 * are protected with bdev_lock. bd_mutex is to
1528 * synchronize disk_holder unlinking.
1530 spin_lock(&bdev_lock
);
1532 WARN_ON_ONCE(--bdev
->bd_holders
< 0);
1533 WARN_ON_ONCE(--bdev
->bd_contains
->bd_holders
< 0);
1535 /* bd_contains might point to self, check in a separate step */
1536 if ((bdev_free
= !bdev
->bd_holders
))
1537 bdev
->bd_holder
= NULL
;
1538 if (!bdev
->bd_contains
->bd_holders
)
1539 bdev
->bd_contains
->bd_holder
= NULL
;
1541 spin_unlock(&bdev_lock
);
1544 * If this was the last claim, remove holder link and
1545 * unblock evpoll if it was a write holder.
1547 if (bdev_free
&& bdev
->bd_write_holder
) {
1548 disk_unblock_events(bdev
->bd_disk
);
1549 bdev
->bd_write_holder
= false;
1554 * Trigger event checking and tell drivers to flush MEDIA_CHANGE
1555 * event. This is to ensure detection of media removal commanded
1556 * from userland - e.g. eject(1).
1558 disk_flush_events(bdev
->bd_disk
, DISK_EVENT_MEDIA_CHANGE
);
1560 mutex_unlock(&bdev
->bd_mutex
);
1562 return __blkdev_put(bdev
, mode
, 0);
1564 EXPORT_SYMBOL(blkdev_put
);
1566 static int blkdev_close(struct inode
* inode
, struct file
* filp
)
1568 struct block_device
*bdev
= I_BDEV(filp
->f_mapping
->host
);
1570 return blkdev_put(bdev
, filp
->f_mode
);
1573 static long block_ioctl(struct file
*file
, unsigned cmd
, unsigned long arg
)
1575 struct block_device
*bdev
= I_BDEV(file
->f_mapping
->host
);
1576 fmode_t mode
= file
->f_mode
;
1579 * O_NDELAY can be altered using fcntl(.., F_SETFL, ..), so we have
1580 * to updated it before every ioctl.
1582 if (file
->f_flags
& O_NDELAY
)
1583 mode
|= FMODE_NDELAY
;
1585 mode
&= ~FMODE_NDELAY
;
1587 return blkdev_ioctl(bdev
, mode
, cmd
, arg
);
1590 ssize_t
blkdev_aio_read(struct kiocb
*iocb
, const struct iovec
*iov
,
1591 unsigned long nr_segs
, loff_t pos
)
1594 struct block_device
*bdev
= I_BDEV(iocb
->ki_filp
->f_mapping
->host
);
1596 down_read(&bdev
->bd_block_size_semaphore
);
1598 ret
= generic_file_aio_read(iocb
, iov
, nr_segs
, pos
);
1600 up_read(&bdev
->bd_block_size_semaphore
);
1604 EXPORT_SYMBOL_GPL(blkdev_aio_read
);
1607 * Write data to the block device. Only intended for the block device itself
1608 * and the raw driver which basically is a fake block device.
1610 * Does not take i_mutex for the write and thus is not for general purpose
1613 ssize_t
blkdev_aio_write(struct kiocb
*iocb
, const struct iovec
*iov
,
1614 unsigned long nr_segs
, loff_t pos
)
1616 struct file
*file
= iocb
->ki_filp
;
1617 struct block_device
*bdev
= I_BDEV(file
->f_mapping
->host
);
1618 struct blk_plug plug
;
1621 BUG_ON(iocb
->ki_pos
!= pos
);
1623 blk_start_plug(&plug
);
1625 down_read(&bdev
->bd_block_size_semaphore
);
1627 ret
= __generic_file_aio_write(iocb
, iov
, nr_segs
, &iocb
->ki_pos
);
1628 if (ret
> 0 || ret
== -EIOCBQUEUED
) {
1631 err
= generic_write_sync(file
, pos
, ret
);
1632 if (err
< 0 && ret
> 0)
1636 up_read(&bdev
->bd_block_size_semaphore
);
1638 blk_finish_plug(&plug
);
1642 EXPORT_SYMBOL_GPL(blkdev_aio_write
);
1644 int blkdev_mmap(struct file
*file
, struct vm_area_struct
*vma
)
1647 struct block_device
*bdev
= I_BDEV(file
->f_mapping
->host
);
1649 down_read(&bdev
->bd_block_size_semaphore
);
1651 ret
= generic_file_mmap(file
, vma
);
1653 up_read(&bdev
->bd_block_size_semaphore
);
1659 * Try to release a page associated with block device when the system
1660 * is under memory pressure.
1662 static int blkdev_releasepage(struct page
*page
, gfp_t wait
)
1664 struct super_block
*super
= BDEV_I(page
->mapping
->host
)->bdev
.bd_super
;
1666 if (super
&& super
->s_op
->bdev_try_to_free_page
)
1667 return super
->s_op
->bdev_try_to_free_page(super
, page
, wait
);
1669 return try_to_free_buffers(page
);
1672 static const struct address_space_operations def_blk_aops
= {
1673 .readpage
= blkdev_readpage
,
1674 .writepage
= blkdev_writepage
,
1675 .write_begin
= blkdev_write_begin
,
1676 .write_end
= blkdev_write_end
,
1677 .writepages
= generic_writepages
,
1678 .releasepage
= blkdev_releasepage
,
1679 .direct_IO
= blkdev_direct_IO
,
1682 const struct file_operations def_blk_fops
= {
1683 .open
= blkdev_open
,
1684 .release
= blkdev_close
,
1685 .llseek
= block_llseek
,
1686 .read
= do_sync_read
,
1687 .write
= do_sync_write
,
1688 .aio_read
= blkdev_aio_read
,
1689 .aio_write
= blkdev_aio_write
,
1690 .mmap
= blkdev_mmap
,
1691 .fsync
= blkdev_fsync
,
1692 .unlocked_ioctl
= block_ioctl
,
1693 #ifdef CONFIG_COMPAT
1694 .compat_ioctl
= compat_blkdev_ioctl
,
1696 .splice_read
= generic_file_splice_read
,
1697 .splice_write
= generic_file_splice_write
,
1700 int ioctl_by_bdev(struct block_device
*bdev
, unsigned cmd
, unsigned long arg
)
1703 mm_segment_t old_fs
= get_fs();
1705 res
= blkdev_ioctl(bdev
, 0, cmd
, arg
);
1710 EXPORT_SYMBOL(ioctl_by_bdev
);
1713 * lookup_bdev - lookup a struct block_device by name
1714 * @pathname: special file representing the block device
1716 * Get a reference to the blockdevice at @pathname in the current
1717 * namespace if possible and return it. Return ERR_PTR(error)
1720 struct block_device
*lookup_bdev(const char *pathname
)
1722 struct block_device
*bdev
;
1723 struct inode
*inode
;
1727 if (!pathname
|| !*pathname
)
1728 return ERR_PTR(-EINVAL
);
1730 error
= kern_path(pathname
, LOOKUP_FOLLOW
, &path
);
1732 return ERR_PTR(error
);
1734 inode
= path
.dentry
->d_inode
;
1736 if (!S_ISBLK(inode
->i_mode
))
1739 if (path
.mnt
->mnt_flags
& MNT_NODEV
)
1742 bdev
= bd_acquire(inode
);
1749 bdev
= ERR_PTR(error
);
1752 EXPORT_SYMBOL(lookup_bdev
);
1754 int __invalidate_device(struct block_device
*bdev
, bool kill_dirty
)
1756 struct super_block
*sb
= get_super(bdev
);
1761 * no need to lock the super, get_super holds the
1762 * read mutex so the filesystem cannot go away
1763 * under us (->put_super runs with the write lock
1766 shrink_dcache_sb(sb
);
1767 res
= invalidate_inodes(sb
, kill_dirty
);
1770 invalidate_bdev(bdev
);
1773 EXPORT_SYMBOL(__invalidate_device
);
1775 void iterate_bdevs(void (*func
)(struct block_device
*, void *), void *arg
)
1777 struct inode
*inode
, *old_inode
= NULL
;
1779 spin_lock(&inode_sb_list_lock
);
1780 list_for_each_entry(inode
, &blockdev_superblock
->s_inodes
, i_sb_list
) {
1781 struct address_space
*mapping
= inode
->i_mapping
;
1783 spin_lock(&inode
->i_lock
);
1784 if (inode
->i_state
& (I_FREEING
|I_WILL_FREE
|I_NEW
) ||
1785 mapping
->nrpages
== 0) {
1786 spin_unlock(&inode
->i_lock
);
1790 spin_unlock(&inode
->i_lock
);
1791 spin_unlock(&inode_sb_list_lock
);
1793 * We hold a reference to 'inode' so it couldn't have been
1794 * removed from s_inodes list while we dropped the
1795 * inode_sb_list_lock. We cannot iput the inode now as we can
1796 * be holding the last reference and we cannot iput it under
1797 * inode_sb_list_lock. So we keep the reference and iput it
1803 func(I_BDEV(inode
), arg
);
1805 spin_lock(&inode_sb_list_lock
);
1807 spin_unlock(&inode_sb_list_lock
);