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 <linux/aio.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 inline struct block_device
*I_BDEV(struct inode
*inode
)
48 return &BDEV_I(inode
)->bdev
;
50 EXPORT_SYMBOL(I_BDEV
);
53 * Move the inode from its current bdi to a new bdi. If the inode is dirty we
54 * need to move it onto the dirty list of @dst so that the inode is always on
57 static void bdev_inode_switch_bdi(struct inode
*inode
,
58 struct backing_dev_info
*dst
)
60 struct backing_dev_info
*old
= inode
->i_data
.backing_dev_info
;
62 if (unlikely(dst
== old
)) /* deadlock avoidance */
64 bdi_lock_two(&old
->wb
, &dst
->wb
);
65 spin_lock(&inode
->i_lock
);
66 inode
->i_data
.backing_dev_info
= dst
;
67 if (inode
->i_state
& I_DIRTY
)
68 list_move(&inode
->i_wb_list
, &dst
->wb
.b_dirty
);
69 spin_unlock(&inode
->i_lock
);
70 spin_unlock(&old
->wb
.list_lock
);
71 spin_unlock(&dst
->wb
.list_lock
);
74 /* Kill _all_ buffers and pagecache , dirty or not.. */
75 void kill_bdev(struct block_device
*bdev
)
77 struct address_space
*mapping
= bdev
->bd_inode
->i_mapping
;
79 if (mapping
->nrpages
== 0)
83 truncate_inode_pages(mapping
, 0);
85 EXPORT_SYMBOL(kill_bdev
);
87 /* Invalidate clean unused buffers and pagecache. */
88 void invalidate_bdev(struct block_device
*bdev
)
90 struct address_space
*mapping
= bdev
->bd_inode
->i_mapping
;
92 if (mapping
->nrpages
== 0)
96 lru_add_drain_all(); /* make sure all lru add caches are flushed */
97 invalidate_mapping_pages(mapping
, 0, -1);
98 /* 99% of the time, we don't need to flush the cleancache on the bdev.
99 * But, for the strange corners, lets be cautious
101 cleancache_invalidate_inode(mapping
);
103 EXPORT_SYMBOL(invalidate_bdev
);
105 int set_blocksize(struct block_device
*bdev
, int size
)
107 /* Size must be a power of two, and between 512 and PAGE_SIZE */
108 if (size
> PAGE_SIZE
|| size
< 512 || !is_power_of_2(size
))
111 /* Size cannot be smaller than the size supported by the device */
112 if (size
< bdev_logical_block_size(bdev
))
115 /* Don't change the size if it is same as current */
116 if (bdev
->bd_block_size
!= size
) {
118 bdev
->bd_block_size
= size
;
119 bdev
->bd_inode
->i_blkbits
= blksize_bits(size
);
125 EXPORT_SYMBOL(set_blocksize
);
127 int sb_set_blocksize(struct super_block
*sb
, int size
)
129 if (set_blocksize(sb
->s_bdev
, size
))
131 /* If we get here, we know size is power of two
132 * and it's value is between 512 and PAGE_SIZE */
133 sb
->s_blocksize
= size
;
134 sb
->s_blocksize_bits
= blksize_bits(size
);
135 return sb
->s_blocksize
;
138 EXPORT_SYMBOL(sb_set_blocksize
);
140 int sb_min_blocksize(struct super_block
*sb
, int size
)
142 int minsize
= bdev_logical_block_size(sb
->s_bdev
);
145 return sb_set_blocksize(sb
, size
);
148 EXPORT_SYMBOL(sb_min_blocksize
);
151 blkdev_get_block(struct inode
*inode
, sector_t iblock
,
152 struct buffer_head
*bh
, int create
)
154 bh
->b_bdev
= I_BDEV(inode
);
155 bh
->b_blocknr
= iblock
;
156 set_buffer_mapped(bh
);
161 blkdev_direct_IO(int rw
, struct kiocb
*iocb
, const struct iovec
*iov
,
162 loff_t offset
, unsigned long nr_segs
)
164 struct file
*file
= iocb
->ki_filp
;
165 struct inode
*inode
= file
->f_mapping
->host
;
167 return __blockdev_direct_IO(rw
, iocb
, inode
, I_BDEV(inode
), iov
, offset
,
168 nr_segs
, blkdev_get_block
, NULL
, NULL
, 0);
171 int __sync_blockdev(struct block_device
*bdev
, int wait
)
176 return filemap_flush(bdev
->bd_inode
->i_mapping
);
177 return filemap_write_and_wait(bdev
->bd_inode
->i_mapping
);
181 * Write out and wait upon all the dirty data associated with a block
182 * device via its mapping. Does not take the superblock lock.
184 int sync_blockdev(struct block_device
*bdev
)
186 return __sync_blockdev(bdev
, 1);
188 EXPORT_SYMBOL(sync_blockdev
);
191 * Write out and wait upon all dirty data associated with this
192 * device. Filesystem data as well as the underlying block
193 * device. Takes the superblock lock.
195 int fsync_bdev(struct block_device
*bdev
)
197 struct super_block
*sb
= get_super(bdev
);
199 int res
= sync_filesystem(sb
);
203 return sync_blockdev(bdev
);
205 EXPORT_SYMBOL(fsync_bdev
);
208 * freeze_bdev -- lock a filesystem and force it into a consistent state
209 * @bdev: blockdevice to lock
211 * If a superblock is found on this device, we take the s_umount semaphore
212 * on it to make sure nobody unmounts until the snapshot creation is done.
213 * The reference counter (bd_fsfreeze_count) guarantees that only the last
214 * unfreeze process can unfreeze the frozen filesystem actually when multiple
215 * freeze requests arrive simultaneously. It counts up in freeze_bdev() and
216 * count down in thaw_bdev(). When it becomes 0, thaw_bdev() will unfreeze
219 struct super_block
*freeze_bdev(struct block_device
*bdev
)
221 struct super_block
*sb
;
224 mutex_lock(&bdev
->bd_fsfreeze_mutex
);
225 if (++bdev
->bd_fsfreeze_count
> 1) {
227 * We don't even need to grab a reference - the first call
228 * to freeze_bdev grab an active reference and only the last
229 * thaw_bdev drops it.
231 sb
= get_super(bdev
);
233 mutex_unlock(&bdev
->bd_fsfreeze_mutex
);
237 sb
= get_active_super(bdev
);
240 error
= freeze_super(sb
);
242 deactivate_super(sb
);
243 bdev
->bd_fsfreeze_count
--;
244 mutex_unlock(&bdev
->bd_fsfreeze_mutex
);
245 return ERR_PTR(error
);
247 deactivate_super(sb
);
250 mutex_unlock(&bdev
->bd_fsfreeze_mutex
);
251 return sb
; /* thaw_bdev releases s->s_umount */
253 EXPORT_SYMBOL(freeze_bdev
);
256 * thaw_bdev -- unlock filesystem
257 * @bdev: blockdevice to unlock
258 * @sb: associated superblock
260 * Unlocks the filesystem and marks it writeable again after freeze_bdev().
262 int thaw_bdev(struct block_device
*bdev
, struct super_block
*sb
)
266 mutex_lock(&bdev
->bd_fsfreeze_mutex
);
267 if (!bdev
->bd_fsfreeze_count
)
271 if (--bdev
->bd_fsfreeze_count
> 0)
277 error
= thaw_super(sb
);
279 bdev
->bd_fsfreeze_count
++;
280 mutex_unlock(&bdev
->bd_fsfreeze_mutex
);
284 mutex_unlock(&bdev
->bd_fsfreeze_mutex
);
287 EXPORT_SYMBOL(thaw_bdev
);
289 static int blkdev_writepage(struct page
*page
, struct writeback_control
*wbc
)
291 return block_write_full_page(page
, blkdev_get_block
, wbc
);
294 static int blkdev_readpage(struct file
* file
, struct page
* page
)
296 return block_read_full_page(page
, blkdev_get_block
);
299 static int blkdev_write_begin(struct file
*file
, struct address_space
*mapping
,
300 loff_t pos
, unsigned len
, unsigned flags
,
301 struct page
**pagep
, void **fsdata
)
303 return block_write_begin(mapping
, pos
, len
, flags
, pagep
,
307 static int blkdev_write_end(struct file
*file
, struct address_space
*mapping
,
308 loff_t pos
, unsigned len
, unsigned copied
,
309 struct page
*page
, void *fsdata
)
312 ret
= block_write_end(file
, mapping
, pos
, len
, copied
, page
, fsdata
);
315 page_cache_release(page
);
322 * for a block special file file_inode(file)->i_size is zero
323 * so we compute the size by hand (just as in block_read/write above)
325 static loff_t
block_llseek(struct file
*file
, loff_t offset
, int whence
)
327 struct inode
*bd_inode
= file
->f_mapping
->host
;
330 mutex_lock(&bd_inode
->i_mutex
);
331 retval
= fixed_size_llseek(file
, offset
, whence
, i_size_read(bd_inode
));
332 mutex_unlock(&bd_inode
->i_mutex
);
336 int blkdev_fsync(struct file
*filp
, loff_t start
, loff_t end
, int datasync
)
338 struct inode
*bd_inode
= filp
->f_mapping
->host
;
339 struct block_device
*bdev
= I_BDEV(bd_inode
);
342 error
= filemap_write_and_wait_range(filp
->f_mapping
, start
, end
);
347 * There is no need to serialise calls to blkdev_issue_flush with
348 * i_mutex and doing so causes performance issues with concurrent
349 * O_SYNC writers to a block device.
351 error
= blkdev_issue_flush(bdev
, GFP_KERNEL
, NULL
);
352 if (error
== -EOPNOTSUPP
)
357 EXPORT_SYMBOL(blkdev_fsync
);
363 static __cacheline_aligned_in_smp
DEFINE_SPINLOCK(bdev_lock
);
364 static struct kmem_cache
* bdev_cachep __read_mostly
;
366 static struct inode
*bdev_alloc_inode(struct super_block
*sb
)
368 struct bdev_inode
*ei
= kmem_cache_alloc(bdev_cachep
, GFP_KERNEL
);
371 return &ei
->vfs_inode
;
374 static void bdev_i_callback(struct rcu_head
*head
)
376 struct inode
*inode
= container_of(head
, struct inode
, i_rcu
);
377 struct bdev_inode
*bdi
= BDEV_I(inode
);
379 kmem_cache_free(bdev_cachep
, bdi
);
382 static void bdev_destroy_inode(struct inode
*inode
)
384 call_rcu(&inode
->i_rcu
, bdev_i_callback
);
387 static void init_once(void *foo
)
389 struct bdev_inode
*ei
= (struct bdev_inode
*) foo
;
390 struct block_device
*bdev
= &ei
->bdev
;
392 memset(bdev
, 0, sizeof(*bdev
));
393 mutex_init(&bdev
->bd_mutex
);
394 INIT_LIST_HEAD(&bdev
->bd_inodes
);
395 INIT_LIST_HEAD(&bdev
->bd_list
);
397 INIT_LIST_HEAD(&bdev
->bd_holder_disks
);
399 inode_init_once(&ei
->vfs_inode
);
400 /* Initialize mutex for freeze. */
401 mutex_init(&bdev
->bd_fsfreeze_mutex
);
404 static inline void __bd_forget(struct inode
*inode
)
406 list_del_init(&inode
->i_devices
);
407 inode
->i_bdev
= NULL
;
408 inode
->i_mapping
= &inode
->i_data
;
411 static void bdev_evict_inode(struct inode
*inode
)
413 struct block_device
*bdev
= &BDEV_I(inode
)->bdev
;
415 truncate_inode_pages(&inode
->i_data
, 0);
416 invalidate_inode_buffers(inode
); /* is it needed here? */
418 spin_lock(&bdev_lock
);
419 while ( (p
= bdev
->bd_inodes
.next
) != &bdev
->bd_inodes
) {
420 __bd_forget(list_entry(p
, struct inode
, i_devices
));
422 list_del_init(&bdev
->bd_list
);
423 spin_unlock(&bdev_lock
);
426 static const struct super_operations bdev_sops
= {
427 .statfs
= simple_statfs
,
428 .alloc_inode
= bdev_alloc_inode
,
429 .destroy_inode
= bdev_destroy_inode
,
430 .drop_inode
= generic_delete_inode
,
431 .evict_inode
= bdev_evict_inode
,
434 static struct dentry
*bd_mount(struct file_system_type
*fs_type
,
435 int flags
, const char *dev_name
, void *data
)
437 return mount_pseudo(fs_type
, "bdev:", &bdev_sops
, NULL
, BDEVFS_MAGIC
);
440 static struct file_system_type bd_type
= {
443 .kill_sb
= kill_anon_super
,
446 static struct super_block
*blockdev_superblock __read_mostly
;
448 void __init
bdev_cache_init(void)
451 static struct vfsmount
*bd_mnt
;
453 bdev_cachep
= kmem_cache_create("bdev_cache", sizeof(struct bdev_inode
),
454 0, (SLAB_HWCACHE_ALIGN
|SLAB_RECLAIM_ACCOUNT
|
455 SLAB_MEM_SPREAD
|SLAB_PANIC
),
457 err
= register_filesystem(&bd_type
);
459 panic("Cannot register bdev pseudo-fs");
460 bd_mnt
= kern_mount(&bd_type
);
462 panic("Cannot create bdev pseudo-fs");
463 blockdev_superblock
= bd_mnt
->mnt_sb
; /* For writeback */
467 * Most likely _very_ bad one - but then it's hardly critical for small
468 * /dev and can be fixed when somebody will need really large one.
469 * Keep in mind that it will be fed through icache hash function too.
471 static inline unsigned long hash(dev_t dev
)
473 return MAJOR(dev
)+MINOR(dev
);
476 static int bdev_test(struct inode
*inode
, void *data
)
478 return BDEV_I(inode
)->bdev
.bd_dev
== *(dev_t
*)data
;
481 static int bdev_set(struct inode
*inode
, void *data
)
483 BDEV_I(inode
)->bdev
.bd_dev
= *(dev_t
*)data
;
487 static LIST_HEAD(all_bdevs
);
489 struct block_device
*bdget(dev_t dev
)
491 struct block_device
*bdev
;
494 inode
= iget5_locked(blockdev_superblock
, hash(dev
),
495 bdev_test
, bdev_set
, &dev
);
500 bdev
= &BDEV_I(inode
)->bdev
;
502 if (inode
->i_state
& I_NEW
) {
503 bdev
->bd_contains
= NULL
;
504 bdev
->bd_super
= NULL
;
505 bdev
->bd_inode
= inode
;
506 bdev
->bd_block_size
= (1 << inode
->i_blkbits
);
507 bdev
->bd_part_count
= 0;
508 bdev
->bd_invalidated
= 0;
509 inode
->i_mode
= S_IFBLK
;
511 inode
->i_bdev
= bdev
;
512 inode
->i_data
.a_ops
= &def_blk_aops
;
513 mapping_set_gfp_mask(&inode
->i_data
, GFP_USER
);
514 inode
->i_data
.backing_dev_info
= &default_backing_dev_info
;
515 spin_lock(&bdev_lock
);
516 list_add(&bdev
->bd_list
, &all_bdevs
);
517 spin_unlock(&bdev_lock
);
518 unlock_new_inode(inode
);
523 EXPORT_SYMBOL(bdget
);
526 * bdgrab -- Grab a reference to an already referenced block device
527 * @bdev: Block device to grab a reference to.
529 struct block_device
*bdgrab(struct block_device
*bdev
)
531 ihold(bdev
->bd_inode
);
534 EXPORT_SYMBOL(bdgrab
);
536 long nr_blockdev_pages(void)
538 struct block_device
*bdev
;
540 spin_lock(&bdev_lock
);
541 list_for_each_entry(bdev
, &all_bdevs
, bd_list
) {
542 ret
+= bdev
->bd_inode
->i_mapping
->nrpages
;
544 spin_unlock(&bdev_lock
);
548 void bdput(struct block_device
*bdev
)
550 iput(bdev
->bd_inode
);
553 EXPORT_SYMBOL(bdput
);
555 static struct block_device
*bd_acquire(struct inode
*inode
)
557 struct block_device
*bdev
;
559 spin_lock(&bdev_lock
);
560 bdev
= inode
->i_bdev
;
562 ihold(bdev
->bd_inode
);
563 spin_unlock(&bdev_lock
);
566 spin_unlock(&bdev_lock
);
568 bdev
= bdget(inode
->i_rdev
);
570 spin_lock(&bdev_lock
);
571 if (!inode
->i_bdev
) {
573 * We take an additional reference to bd_inode,
574 * and it's released in clear_inode() of inode.
575 * So, we can access it via ->i_mapping always
578 ihold(bdev
->bd_inode
);
579 inode
->i_bdev
= bdev
;
580 inode
->i_mapping
= bdev
->bd_inode
->i_mapping
;
581 list_add(&inode
->i_devices
, &bdev
->bd_inodes
);
583 spin_unlock(&bdev_lock
);
588 static inline int sb_is_blkdev_sb(struct super_block
*sb
)
590 return sb
== blockdev_superblock
;
593 /* Call when you free inode */
595 void bd_forget(struct inode
*inode
)
597 struct block_device
*bdev
= NULL
;
599 spin_lock(&bdev_lock
);
600 if (!sb_is_blkdev_sb(inode
->i_sb
))
601 bdev
= inode
->i_bdev
;
603 spin_unlock(&bdev_lock
);
606 iput(bdev
->bd_inode
);
610 * bd_may_claim - test whether a block device can be claimed
611 * @bdev: block device of interest
612 * @whole: whole block device containing @bdev, may equal @bdev
613 * @holder: holder trying to claim @bdev
615 * Test whether @bdev can be claimed by @holder.
618 * spin_lock(&bdev_lock).
621 * %true if @bdev can be claimed, %false otherwise.
623 static bool bd_may_claim(struct block_device
*bdev
, struct block_device
*whole
,
626 if (bdev
->bd_holder
== holder
)
627 return true; /* already a holder */
628 else if (bdev
->bd_holder
!= NULL
)
629 return false; /* held by someone else */
630 else if (bdev
->bd_contains
== bdev
)
631 return true; /* is a whole device which isn't held */
633 else if (whole
->bd_holder
== bd_may_claim
)
634 return true; /* is a partition of a device that is being partitioned */
635 else if (whole
->bd_holder
!= NULL
)
636 return false; /* is a partition of a held device */
638 return true; /* is a partition of an un-held device */
642 * bd_prepare_to_claim - prepare to claim a block device
643 * @bdev: block device of interest
644 * @whole: the whole device containing @bdev, may equal @bdev
645 * @holder: holder trying to claim @bdev
647 * Prepare to claim @bdev. This function fails if @bdev is already
648 * claimed by another holder and waits if another claiming is in
649 * progress. This function doesn't actually claim. On successful
650 * return, the caller has ownership of bd_claiming and bd_holder[s].
653 * spin_lock(&bdev_lock). Might release bdev_lock, sleep and regrab
657 * 0 if @bdev can be claimed, -EBUSY otherwise.
659 static int bd_prepare_to_claim(struct block_device
*bdev
,
660 struct block_device
*whole
, void *holder
)
663 /* if someone else claimed, fail */
664 if (!bd_may_claim(bdev
, whole
, holder
))
667 /* if claiming is already in progress, wait for it to finish */
668 if (whole
->bd_claiming
) {
669 wait_queue_head_t
*wq
= bit_waitqueue(&whole
->bd_claiming
, 0);
672 prepare_to_wait(wq
, &wait
, TASK_UNINTERRUPTIBLE
);
673 spin_unlock(&bdev_lock
);
675 finish_wait(wq
, &wait
);
676 spin_lock(&bdev_lock
);
685 * bd_start_claiming - start claiming a block device
686 * @bdev: block device of interest
687 * @holder: holder trying to claim @bdev
689 * @bdev is about to be opened exclusively. Check @bdev can be opened
690 * exclusively and mark that an exclusive open is in progress. Each
691 * successful call to this function must be matched with a call to
692 * either bd_finish_claiming() or bd_abort_claiming() (which do not
695 * This function is used to gain exclusive access to the block device
696 * without actually causing other exclusive open attempts to fail. It
697 * should be used when the open sequence itself requires exclusive
698 * access but may subsequently fail.
704 * Pointer to the block device containing @bdev on success, ERR_PTR()
707 static struct block_device
*bd_start_claiming(struct block_device
*bdev
,
710 struct gendisk
*disk
;
711 struct block_device
*whole
;
717 * @bdev might not have been initialized properly yet, look up
718 * and grab the outer block device the hard way.
720 disk
= get_gendisk(bdev
->bd_dev
, &partno
);
722 return ERR_PTR(-ENXIO
);
725 * Normally, @bdev should equal what's returned from bdget_disk()
726 * if partno is 0; however, some drivers (floppy) use multiple
727 * bdev's for the same physical device and @bdev may be one of the
728 * aliases. Keep @bdev if partno is 0. This means claimer
729 * tracking is broken for those devices but it has always been that
733 whole
= bdget_disk(disk
, 0);
735 whole
= bdgrab(bdev
);
737 module_put(disk
->fops
->owner
);
740 return ERR_PTR(-ENOMEM
);
742 /* prepare to claim, if successful, mark claiming in progress */
743 spin_lock(&bdev_lock
);
745 err
= bd_prepare_to_claim(bdev
, whole
, holder
);
747 whole
->bd_claiming
= holder
;
748 spin_unlock(&bdev_lock
);
751 spin_unlock(&bdev_lock
);
758 struct bd_holder_disk
{
759 struct list_head list
;
760 struct gendisk
*disk
;
764 static struct bd_holder_disk
*bd_find_holder_disk(struct block_device
*bdev
,
765 struct gendisk
*disk
)
767 struct bd_holder_disk
*holder
;
769 list_for_each_entry(holder
, &bdev
->bd_holder_disks
, list
)
770 if (holder
->disk
== disk
)
775 static int add_symlink(struct kobject
*from
, struct kobject
*to
)
777 return sysfs_create_link(from
, to
, kobject_name(to
));
780 static void del_symlink(struct kobject
*from
, struct kobject
*to
)
782 sysfs_remove_link(from
, kobject_name(to
));
786 * bd_link_disk_holder - create symlinks between holding disk and slave bdev
787 * @bdev: the claimed slave bdev
788 * @disk: the holding disk
790 * DON'T USE THIS UNLESS YOU'RE ALREADY USING IT.
792 * This functions creates the following sysfs symlinks.
794 * - from "slaves" directory of the holder @disk to the claimed @bdev
795 * - from "holders" directory of the @bdev to the holder @disk
797 * For example, if /dev/dm-0 maps to /dev/sda and disk for dm-0 is
798 * passed to bd_link_disk_holder(), then:
800 * /sys/block/dm-0/slaves/sda --> /sys/block/sda
801 * /sys/block/sda/holders/dm-0 --> /sys/block/dm-0
803 * The caller must have claimed @bdev before calling this function and
804 * ensure that both @bdev and @disk are valid during the creation and
805 * lifetime of these symlinks.
811 * 0 on success, -errno on failure.
813 int bd_link_disk_holder(struct block_device
*bdev
, struct gendisk
*disk
)
815 struct bd_holder_disk
*holder
;
818 mutex_lock(&bdev
->bd_mutex
);
820 WARN_ON_ONCE(!bdev
->bd_holder
);
822 /* FIXME: remove the following once add_disk() handles errors */
823 if (WARN_ON(!disk
->slave_dir
|| !bdev
->bd_part
->holder_dir
))
826 holder
= bd_find_holder_disk(bdev
, disk
);
832 holder
= kzalloc(sizeof(*holder
), GFP_KERNEL
);
838 INIT_LIST_HEAD(&holder
->list
);
842 ret
= add_symlink(disk
->slave_dir
, &part_to_dev(bdev
->bd_part
)->kobj
);
846 ret
= add_symlink(bdev
->bd_part
->holder_dir
, &disk_to_dev(disk
)->kobj
);
850 * bdev could be deleted beneath us which would implicitly destroy
851 * the holder directory. Hold on to it.
853 kobject_get(bdev
->bd_part
->holder_dir
);
855 list_add(&holder
->list
, &bdev
->bd_holder_disks
);
859 del_symlink(disk
->slave_dir
, &part_to_dev(bdev
->bd_part
)->kobj
);
863 mutex_unlock(&bdev
->bd_mutex
);
866 EXPORT_SYMBOL_GPL(bd_link_disk_holder
);
869 * bd_unlink_disk_holder - destroy symlinks created by bd_link_disk_holder()
870 * @bdev: the calimed slave bdev
871 * @disk: the holding disk
873 * DON'T USE THIS UNLESS YOU'RE ALREADY USING IT.
878 void bd_unlink_disk_holder(struct block_device
*bdev
, struct gendisk
*disk
)
880 struct bd_holder_disk
*holder
;
882 mutex_lock(&bdev
->bd_mutex
);
884 holder
= bd_find_holder_disk(bdev
, disk
);
886 if (!WARN_ON_ONCE(holder
== NULL
) && !--holder
->refcnt
) {
887 del_symlink(disk
->slave_dir
, &part_to_dev(bdev
->bd_part
)->kobj
);
888 del_symlink(bdev
->bd_part
->holder_dir
,
889 &disk_to_dev(disk
)->kobj
);
890 kobject_put(bdev
->bd_part
->holder_dir
);
891 list_del_init(&holder
->list
);
895 mutex_unlock(&bdev
->bd_mutex
);
897 EXPORT_SYMBOL_GPL(bd_unlink_disk_holder
);
901 * flush_disk - invalidates all buffer-cache entries on a disk
903 * @bdev: struct block device to be flushed
904 * @kill_dirty: flag to guide handling of dirty inodes
906 * Invalidates all buffer-cache entries on a disk. It should be called
907 * when a disk has been changed -- either by a media change or online
910 static void flush_disk(struct block_device
*bdev
, bool kill_dirty
)
912 if (__invalidate_device(bdev
, kill_dirty
)) {
913 char name
[BDEVNAME_SIZE
] = "";
916 disk_name(bdev
->bd_disk
, 0, name
);
917 printk(KERN_WARNING
"VFS: busy inodes on changed media or "
918 "resized disk %s\n", name
);
923 if (disk_part_scan_enabled(bdev
->bd_disk
))
924 bdev
->bd_invalidated
= 1;
928 * check_disk_size_change - checks for disk size change and adjusts bdev size.
929 * @disk: struct gendisk to check
930 * @bdev: struct bdev to adjust.
932 * This routine checks to see if the bdev size does not match the disk size
933 * and adjusts it if it differs.
935 void check_disk_size_change(struct gendisk
*disk
, struct block_device
*bdev
)
937 loff_t disk_size
, bdev_size
;
939 disk_size
= (loff_t
)get_capacity(disk
) << 9;
940 bdev_size
= i_size_read(bdev
->bd_inode
);
941 if (disk_size
!= bdev_size
) {
942 char name
[BDEVNAME_SIZE
];
944 disk_name(disk
, 0, name
);
946 "%s: detected capacity change from %lld to %lld\n",
947 name
, bdev_size
, disk_size
);
948 i_size_write(bdev
->bd_inode
, disk_size
);
949 flush_disk(bdev
, false);
952 EXPORT_SYMBOL(check_disk_size_change
);
955 * revalidate_disk - wrapper for lower-level driver's revalidate_disk call-back
956 * @disk: struct gendisk to be revalidated
958 * This routine is a wrapper for lower-level driver's revalidate_disk
959 * call-backs. It is used to do common pre and post operations needed
960 * for all revalidate_disk operations.
962 int revalidate_disk(struct gendisk
*disk
)
964 struct block_device
*bdev
;
967 if (disk
->fops
->revalidate_disk
)
968 ret
= disk
->fops
->revalidate_disk(disk
);
970 bdev
= bdget_disk(disk
, 0);
974 mutex_lock(&bdev
->bd_mutex
);
975 check_disk_size_change(disk
, bdev
);
976 bdev
->bd_invalidated
= 0;
977 mutex_unlock(&bdev
->bd_mutex
);
981 EXPORT_SYMBOL(revalidate_disk
);
984 * This routine checks whether a removable media has been changed,
985 * and invalidates all buffer-cache-entries in that case. This
986 * is a relatively slow routine, so we have to try to minimize using
987 * it. Thus it is called only upon a 'mount' or 'open'. This
988 * is the best way of combining speed and utility, I think.
989 * People changing diskettes in the middle of an operation deserve
992 int check_disk_change(struct block_device
*bdev
)
994 struct gendisk
*disk
= bdev
->bd_disk
;
995 const struct block_device_operations
*bdops
= disk
->fops
;
998 events
= disk_clear_events(disk
, DISK_EVENT_MEDIA_CHANGE
|
999 DISK_EVENT_EJECT_REQUEST
);
1000 if (!(events
& DISK_EVENT_MEDIA_CHANGE
))
1003 flush_disk(bdev
, true);
1004 if (bdops
->revalidate_disk
)
1005 bdops
->revalidate_disk(bdev
->bd_disk
);
1009 EXPORT_SYMBOL(check_disk_change
);
1011 void bd_set_size(struct block_device
*bdev
, loff_t size
)
1013 unsigned bsize
= bdev_logical_block_size(bdev
);
1015 mutex_lock(&bdev
->bd_inode
->i_mutex
);
1016 i_size_write(bdev
->bd_inode
, size
);
1017 mutex_unlock(&bdev
->bd_inode
->i_mutex
);
1018 while (bsize
< PAGE_CACHE_SIZE
) {
1023 bdev
->bd_block_size
= bsize
;
1024 bdev
->bd_inode
->i_blkbits
= blksize_bits(bsize
);
1026 EXPORT_SYMBOL(bd_set_size
);
1028 static void __blkdev_put(struct block_device
*bdev
, fmode_t mode
, int for_part
);
1033 * mutex_lock(part->bd_mutex)
1034 * mutex_lock_nested(whole->bd_mutex, 1)
1037 static int __blkdev_get(struct block_device
*bdev
, fmode_t mode
, int for_part
)
1039 struct gendisk
*disk
;
1040 struct module
*owner
;
1045 if (mode
& FMODE_READ
)
1047 if (mode
& FMODE_WRITE
)
1050 * hooks: /n/, see "layering violations".
1053 ret
= devcgroup_inode_permission(bdev
->bd_inode
, perm
);
1063 disk
= get_gendisk(bdev
->bd_dev
, &partno
);
1066 owner
= disk
->fops
->owner
;
1068 disk_block_events(disk
);
1069 mutex_lock_nested(&bdev
->bd_mutex
, for_part
);
1070 if (!bdev
->bd_openers
) {
1071 bdev
->bd_disk
= disk
;
1072 bdev
->bd_queue
= disk
->queue
;
1073 bdev
->bd_contains
= bdev
;
1075 struct backing_dev_info
*bdi
;
1078 bdev
->bd_part
= disk_get_part(disk
, partno
);
1083 if (disk
->fops
->open
) {
1084 ret
= disk
->fops
->open(bdev
, mode
);
1085 if (ret
== -ERESTARTSYS
) {
1086 /* Lost a race with 'disk' being
1087 * deleted, try again.
1090 disk_put_part(bdev
->bd_part
);
1091 bdev
->bd_part
= NULL
;
1092 bdev
->bd_disk
= NULL
;
1093 bdev
->bd_queue
= NULL
;
1094 mutex_unlock(&bdev
->bd_mutex
);
1095 disk_unblock_events(disk
);
1103 bd_set_size(bdev
,(loff_t
)get_capacity(disk
)<<9);
1104 bdi
= blk_get_backing_dev_info(bdev
);
1106 bdi
= &default_backing_dev_info
;
1107 bdev_inode_switch_bdi(bdev
->bd_inode
, bdi
);
1111 * If the device is invalidated, rescan partition
1112 * if open succeeded or failed with -ENOMEDIUM.
1113 * The latter is necessary to prevent ghost
1114 * partitions on a removed medium.
1116 if (bdev
->bd_invalidated
) {
1118 rescan_partitions(disk
, bdev
);
1119 else if (ret
== -ENOMEDIUM
)
1120 invalidate_partitions(disk
, bdev
);
1125 struct block_device
*whole
;
1126 whole
= bdget_disk(disk
, 0);
1131 ret
= __blkdev_get(whole
, mode
, 1);
1134 bdev
->bd_contains
= whole
;
1135 bdev_inode_switch_bdi(bdev
->bd_inode
,
1136 whole
->bd_inode
->i_data
.backing_dev_info
);
1137 bdev
->bd_part
= disk_get_part(disk
, partno
);
1138 if (!(disk
->flags
& GENHD_FL_UP
) ||
1139 !bdev
->bd_part
|| !bdev
->bd_part
->nr_sects
) {
1143 bd_set_size(bdev
, (loff_t
)bdev
->bd_part
->nr_sects
<< 9);
1146 if (bdev
->bd_contains
== bdev
) {
1148 if (bdev
->bd_disk
->fops
->open
)
1149 ret
= bdev
->bd_disk
->fops
->open(bdev
, mode
);
1150 /* the same as first opener case, read comment there */
1151 if (bdev
->bd_invalidated
) {
1153 rescan_partitions(bdev
->bd_disk
, bdev
);
1154 else if (ret
== -ENOMEDIUM
)
1155 invalidate_partitions(bdev
->bd_disk
, bdev
);
1158 goto out_unlock_bdev
;
1160 /* only one opener holds refs to the module and disk */
1166 bdev
->bd_part_count
++;
1167 mutex_unlock(&bdev
->bd_mutex
);
1168 disk_unblock_events(disk
);
1172 disk_put_part(bdev
->bd_part
);
1173 bdev
->bd_disk
= NULL
;
1174 bdev
->bd_part
= NULL
;
1175 bdev
->bd_queue
= NULL
;
1176 bdev_inode_switch_bdi(bdev
->bd_inode
, &default_backing_dev_info
);
1177 if (bdev
!= bdev
->bd_contains
)
1178 __blkdev_put(bdev
->bd_contains
, mode
, 1);
1179 bdev
->bd_contains
= NULL
;
1181 mutex_unlock(&bdev
->bd_mutex
);
1182 disk_unblock_events(disk
);
1192 * blkdev_get - open a block device
1193 * @bdev: block_device to open
1194 * @mode: FMODE_* mask
1195 * @holder: exclusive holder identifier
1197 * Open @bdev with @mode. If @mode includes %FMODE_EXCL, @bdev is
1198 * open with exclusive access. Specifying %FMODE_EXCL with %NULL
1199 * @holder is invalid. Exclusive opens may nest for the same @holder.
1201 * On success, the reference count of @bdev is unchanged. On failure,
1208 * 0 on success, -errno on failure.
1210 int blkdev_get(struct block_device
*bdev
, fmode_t mode
, void *holder
)
1212 struct block_device
*whole
= NULL
;
1215 WARN_ON_ONCE((mode
& FMODE_EXCL
) && !holder
);
1217 if ((mode
& FMODE_EXCL
) && holder
) {
1218 whole
= bd_start_claiming(bdev
, holder
);
1219 if (IS_ERR(whole
)) {
1221 return PTR_ERR(whole
);
1225 res
= __blkdev_get(bdev
, mode
, 0);
1228 struct gendisk
*disk
= whole
->bd_disk
;
1230 /* finish claiming */
1231 mutex_lock(&bdev
->bd_mutex
);
1232 spin_lock(&bdev_lock
);
1235 BUG_ON(!bd_may_claim(bdev
, whole
, holder
));
1237 * Note that for a whole device bd_holders
1238 * will be incremented twice, and bd_holder
1239 * will be set to bd_may_claim before being
1242 whole
->bd_holders
++;
1243 whole
->bd_holder
= bd_may_claim
;
1245 bdev
->bd_holder
= holder
;
1248 /* tell others that we're done */
1249 BUG_ON(whole
->bd_claiming
!= holder
);
1250 whole
->bd_claiming
= NULL
;
1251 wake_up_bit(&whole
->bd_claiming
, 0);
1253 spin_unlock(&bdev_lock
);
1256 * Block event polling for write claims if requested. Any
1257 * write holder makes the write_holder state stick until
1258 * all are released. This is good enough and tracking
1259 * individual writeable reference is too fragile given the
1260 * way @mode is used in blkdev_get/put().
1262 if (!res
&& (mode
& FMODE_WRITE
) && !bdev
->bd_write_holder
&&
1263 (disk
->flags
& GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE
)) {
1264 bdev
->bd_write_holder
= true;
1265 disk_block_events(disk
);
1268 mutex_unlock(&bdev
->bd_mutex
);
1274 EXPORT_SYMBOL(blkdev_get
);
1277 * blkdev_get_by_path - open a block device by name
1278 * @path: path to the block device to open
1279 * @mode: FMODE_* mask
1280 * @holder: exclusive holder identifier
1282 * Open the blockdevice described by the device file at @path. @mode
1283 * and @holder are identical to blkdev_get().
1285 * On success, the returned block_device has reference count of one.
1291 * Pointer to block_device on success, ERR_PTR(-errno) on failure.
1293 struct block_device
*blkdev_get_by_path(const char *path
, fmode_t mode
,
1296 struct block_device
*bdev
;
1299 bdev
= lookup_bdev(path
);
1303 err
= blkdev_get(bdev
, mode
, holder
);
1305 return ERR_PTR(err
);
1307 if ((mode
& FMODE_WRITE
) && bdev_read_only(bdev
)) {
1308 blkdev_put(bdev
, mode
);
1309 return ERR_PTR(-EACCES
);
1314 EXPORT_SYMBOL(blkdev_get_by_path
);
1317 * blkdev_get_by_dev - open a block device by device number
1318 * @dev: device number of block device to open
1319 * @mode: FMODE_* mask
1320 * @holder: exclusive holder identifier
1322 * Open the blockdevice described by device number @dev. @mode and
1323 * @holder are identical to blkdev_get().
1325 * Use it ONLY if you really do not have anything better - i.e. when
1326 * you are behind a truly sucky interface and all you are given is a
1327 * device number. _Never_ to be used for internal purposes. If you
1328 * ever need it - reconsider your API.
1330 * On success, the returned block_device has reference count of one.
1336 * Pointer to block_device on success, ERR_PTR(-errno) on failure.
1338 struct block_device
*blkdev_get_by_dev(dev_t dev
, fmode_t mode
, void *holder
)
1340 struct block_device
*bdev
;
1345 return ERR_PTR(-ENOMEM
);
1347 err
= blkdev_get(bdev
, mode
, holder
);
1349 return ERR_PTR(err
);
1353 EXPORT_SYMBOL(blkdev_get_by_dev
);
1355 static int blkdev_open(struct inode
* inode
, struct file
* filp
)
1357 struct block_device
*bdev
;
1360 * Preserve backwards compatibility and allow large file access
1361 * even if userspace doesn't ask for it explicitly. Some mkfs
1362 * binary needs it. We might want to drop this workaround
1363 * during an unstable branch.
1365 filp
->f_flags
|= O_LARGEFILE
;
1367 if (filp
->f_flags
& O_NDELAY
)
1368 filp
->f_mode
|= FMODE_NDELAY
;
1369 if (filp
->f_flags
& O_EXCL
)
1370 filp
->f_mode
|= FMODE_EXCL
;
1371 if ((filp
->f_flags
& O_ACCMODE
) == 3)
1372 filp
->f_mode
|= FMODE_WRITE_IOCTL
;
1374 bdev
= bd_acquire(inode
);
1378 filp
->f_mapping
= bdev
->bd_inode
->i_mapping
;
1380 return blkdev_get(bdev
, filp
->f_mode
, filp
);
1383 static void __blkdev_put(struct block_device
*bdev
, fmode_t mode
, int for_part
)
1385 struct gendisk
*disk
= bdev
->bd_disk
;
1386 struct block_device
*victim
= NULL
;
1388 mutex_lock_nested(&bdev
->bd_mutex
, for_part
);
1390 bdev
->bd_part_count
--;
1392 if (!--bdev
->bd_openers
) {
1393 WARN_ON_ONCE(bdev
->bd_holders
);
1394 sync_blockdev(bdev
);
1396 /* ->release can cause the old bdi to disappear,
1397 * so must switch it out first
1399 bdev_inode_switch_bdi(bdev
->bd_inode
,
1400 &default_backing_dev_info
);
1402 if (bdev
->bd_contains
== bdev
) {
1403 if (disk
->fops
->release
)
1404 disk
->fops
->release(disk
, mode
);
1406 if (!bdev
->bd_openers
) {
1407 struct module
*owner
= disk
->fops
->owner
;
1409 disk_put_part(bdev
->bd_part
);
1410 bdev
->bd_part
= NULL
;
1411 bdev
->bd_disk
= NULL
;
1412 if (bdev
!= bdev
->bd_contains
)
1413 victim
= bdev
->bd_contains
;
1414 bdev
->bd_contains
= NULL
;
1419 mutex_unlock(&bdev
->bd_mutex
);
1422 __blkdev_put(victim
, mode
, 1);
1425 void blkdev_put(struct block_device
*bdev
, fmode_t mode
)
1427 mutex_lock(&bdev
->bd_mutex
);
1429 if (mode
& FMODE_EXCL
) {
1433 * Release a claim on the device. The holder fields
1434 * are protected with bdev_lock. bd_mutex is to
1435 * synchronize disk_holder unlinking.
1437 spin_lock(&bdev_lock
);
1439 WARN_ON_ONCE(--bdev
->bd_holders
< 0);
1440 WARN_ON_ONCE(--bdev
->bd_contains
->bd_holders
< 0);
1442 /* bd_contains might point to self, check in a separate step */
1443 if ((bdev_free
= !bdev
->bd_holders
))
1444 bdev
->bd_holder
= NULL
;
1445 if (!bdev
->bd_contains
->bd_holders
)
1446 bdev
->bd_contains
->bd_holder
= NULL
;
1448 spin_unlock(&bdev_lock
);
1451 * If this was the last claim, remove holder link and
1452 * unblock evpoll if it was a write holder.
1454 if (bdev_free
&& bdev
->bd_write_holder
) {
1455 disk_unblock_events(bdev
->bd_disk
);
1456 bdev
->bd_write_holder
= false;
1461 * Trigger event checking and tell drivers to flush MEDIA_CHANGE
1462 * event. This is to ensure detection of media removal commanded
1463 * from userland - e.g. eject(1).
1465 disk_flush_events(bdev
->bd_disk
, DISK_EVENT_MEDIA_CHANGE
);
1467 mutex_unlock(&bdev
->bd_mutex
);
1469 __blkdev_put(bdev
, mode
, 0);
1471 EXPORT_SYMBOL(blkdev_put
);
1473 static int blkdev_close(struct inode
* inode
, struct file
* filp
)
1475 struct block_device
*bdev
= I_BDEV(filp
->f_mapping
->host
);
1476 blkdev_put(bdev
, filp
->f_mode
);
1480 static long block_ioctl(struct file
*file
, unsigned cmd
, unsigned long arg
)
1482 struct block_device
*bdev
= I_BDEV(file
->f_mapping
->host
);
1483 fmode_t mode
= file
->f_mode
;
1486 * O_NDELAY can be altered using fcntl(.., F_SETFL, ..), so we have
1487 * to updated it before every ioctl.
1489 if (file
->f_flags
& O_NDELAY
)
1490 mode
|= FMODE_NDELAY
;
1492 mode
&= ~FMODE_NDELAY
;
1494 return blkdev_ioctl(bdev
, mode
, cmd
, arg
);
1498 * Write data to the block device. Only intended for the block device itself
1499 * and the raw driver which basically is a fake block device.
1501 * Does not take i_mutex for the write and thus is not for general purpose
1504 ssize_t
blkdev_aio_write(struct kiocb
*iocb
, const struct iovec
*iov
,
1505 unsigned long nr_segs
, loff_t pos
)
1507 struct file
*file
= iocb
->ki_filp
;
1508 struct blk_plug plug
;
1511 BUG_ON(iocb
->ki_pos
!= pos
);
1513 blk_start_plug(&plug
);
1514 ret
= __generic_file_aio_write(iocb
, iov
, nr_segs
, &iocb
->ki_pos
);
1515 if (ret
> 0 || ret
== -EIOCBQUEUED
) {
1518 err
= generic_write_sync(file
, pos
, ret
);
1519 if (err
< 0 && ret
> 0)
1522 blk_finish_plug(&plug
);
1525 EXPORT_SYMBOL_GPL(blkdev_aio_write
);
1527 static ssize_t
blkdev_aio_read(struct kiocb
*iocb
, const struct iovec
*iov
,
1528 unsigned long nr_segs
, loff_t pos
)
1530 struct file
*file
= iocb
->ki_filp
;
1531 struct inode
*bd_inode
= file
->f_mapping
->host
;
1532 loff_t size
= i_size_read(bd_inode
);
1538 if (size
< iocb
->ki_left
)
1539 nr_segs
= iov_shorten((struct iovec
*)iov
, nr_segs
, size
);
1540 return generic_file_aio_read(iocb
, iov
, nr_segs
, pos
);
1544 * Try to release a page associated with block device when the system
1545 * is under memory pressure.
1547 static int blkdev_releasepage(struct page
*page
, gfp_t wait
)
1549 struct super_block
*super
= BDEV_I(page
->mapping
->host
)->bdev
.bd_super
;
1551 if (super
&& super
->s_op
->bdev_try_to_free_page
)
1552 return super
->s_op
->bdev_try_to_free_page(super
, page
, wait
);
1554 return try_to_free_buffers(page
);
1557 static const struct address_space_operations def_blk_aops
= {
1558 .readpage
= blkdev_readpage
,
1559 .writepage
= blkdev_writepage
,
1560 .write_begin
= blkdev_write_begin
,
1561 .write_end
= blkdev_write_end
,
1562 .writepages
= generic_writepages
,
1563 .releasepage
= blkdev_releasepage
,
1564 .direct_IO
= blkdev_direct_IO
,
1565 .is_dirty_writeback
= buffer_check_dirty_writeback
,
1568 const struct file_operations def_blk_fops
= {
1569 .open
= blkdev_open
,
1570 .release
= blkdev_close
,
1571 .llseek
= block_llseek
,
1572 .read
= do_sync_read
,
1573 .write
= do_sync_write
,
1574 .aio_read
= blkdev_aio_read
,
1575 .aio_write
= blkdev_aio_write
,
1576 .mmap
= generic_file_mmap
,
1577 .fsync
= blkdev_fsync
,
1578 .unlocked_ioctl
= block_ioctl
,
1579 #ifdef CONFIG_COMPAT
1580 .compat_ioctl
= compat_blkdev_ioctl
,
1582 .splice_read
= generic_file_splice_read
,
1583 .splice_write
= generic_file_splice_write
,
1586 int ioctl_by_bdev(struct block_device
*bdev
, unsigned cmd
, unsigned long arg
)
1589 mm_segment_t old_fs
= get_fs();
1591 res
= blkdev_ioctl(bdev
, 0, cmd
, arg
);
1596 EXPORT_SYMBOL(ioctl_by_bdev
);
1599 * lookup_bdev - lookup a struct block_device by name
1600 * @pathname: special file representing the block device
1602 * Get a reference to the blockdevice at @pathname in the current
1603 * namespace if possible and return it. Return ERR_PTR(error)
1606 struct block_device
*lookup_bdev(const char *pathname
)
1608 struct block_device
*bdev
;
1609 struct inode
*inode
;
1613 if (!pathname
|| !*pathname
)
1614 return ERR_PTR(-EINVAL
);
1616 error
= kern_path(pathname
, LOOKUP_FOLLOW
, &path
);
1618 return ERR_PTR(error
);
1620 inode
= path
.dentry
->d_inode
;
1622 if (!S_ISBLK(inode
->i_mode
))
1625 if (path
.mnt
->mnt_flags
& MNT_NODEV
)
1628 bdev
= bd_acquire(inode
);
1635 bdev
= ERR_PTR(error
);
1638 EXPORT_SYMBOL(lookup_bdev
);
1640 int __invalidate_device(struct block_device
*bdev
, bool kill_dirty
)
1642 struct super_block
*sb
= get_super(bdev
);
1647 * no need to lock the super, get_super holds the
1648 * read mutex so the filesystem cannot go away
1649 * under us (->put_super runs with the write lock
1652 shrink_dcache_sb(sb
);
1653 res
= invalidate_inodes(sb
, kill_dirty
);
1656 invalidate_bdev(bdev
);
1659 EXPORT_SYMBOL(__invalidate_device
);
1661 void iterate_bdevs(void (*func
)(struct block_device
*, void *), void *arg
)
1663 struct inode
*inode
, *old_inode
= NULL
;
1665 spin_lock(&inode_sb_list_lock
);
1666 list_for_each_entry(inode
, &blockdev_superblock
->s_inodes
, i_sb_list
) {
1667 struct address_space
*mapping
= inode
->i_mapping
;
1669 spin_lock(&inode
->i_lock
);
1670 if (inode
->i_state
& (I_FREEING
|I_WILL_FREE
|I_NEW
) ||
1671 mapping
->nrpages
== 0) {
1672 spin_unlock(&inode
->i_lock
);
1676 spin_unlock(&inode
->i_lock
);
1677 spin_unlock(&inode_sb_list_lock
);
1679 * We hold a reference to 'inode' so it couldn't have been
1680 * removed from s_inodes list while we dropped the
1681 * inode_sb_list_lock. We cannot iput the inode now as we can
1682 * be holding the last reference and we cannot iput it under
1683 * inode_sb_list_lock. So we keep the reference and iput it
1689 func(I_BDEV(inode
), arg
);
1691 spin_lock(&inode_sb_list_lock
);
1693 spin_unlock(&inode_sb_list_lock
);