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/smp_lock.h>
15 #include <linux/device_cgroup.h>
16 #include <linux/highmem.h>
17 #include <linux/blkdev.h>
18 #include <linux/module.h>
19 #include <linux/blkpg.h>
20 #include <linux/buffer_head.h>
21 #include <linux/pagevec.h>
22 #include <linux/writeback.h>
23 #include <linux/mpage.h>
24 #include <linux/mount.h>
25 #include <linux/uio.h>
26 #include <linux/namei.h>
27 #include <linux/log2.h>
28 #include <linux/kmemleak.h>
29 #include <asm/uaccess.h>
33 struct block_device bdev
;
34 struct inode vfs_inode
;
37 static const struct address_space_operations def_blk_aops
;
39 static inline struct bdev_inode
*BDEV_I(struct inode
*inode
)
41 return container_of(inode
, struct bdev_inode
, vfs_inode
);
44 inline struct block_device
*I_BDEV(struct inode
*inode
)
46 return &BDEV_I(inode
)->bdev
;
49 EXPORT_SYMBOL(I_BDEV
);
51 static sector_t
max_block(struct block_device
*bdev
)
53 sector_t retval
= ~((sector_t
)0);
54 loff_t sz
= i_size_read(bdev
->bd_inode
);
57 unsigned int size
= block_size(bdev
);
58 unsigned int sizebits
= blksize_bits(size
);
59 retval
= (sz
>> sizebits
);
64 /* Kill _all_ buffers and pagecache , dirty or not.. */
65 static void kill_bdev(struct block_device
*bdev
)
67 if (bdev
->bd_inode
->i_mapping
->nrpages
== 0)
70 truncate_inode_pages(bdev
->bd_inode
->i_mapping
, 0);
73 int set_blocksize(struct block_device
*bdev
, int size
)
75 /* Size must be a power of two, and between 512 and PAGE_SIZE */
76 if (size
> PAGE_SIZE
|| size
< 512 || !is_power_of_2(size
))
79 /* Size cannot be smaller than the size supported by the device */
80 if (size
< bdev_logical_block_size(bdev
))
83 /* Don't change the size if it is same as current */
84 if (bdev
->bd_block_size
!= size
) {
86 bdev
->bd_block_size
= size
;
87 bdev
->bd_inode
->i_blkbits
= blksize_bits(size
);
93 EXPORT_SYMBOL(set_blocksize
);
95 int sb_set_blocksize(struct super_block
*sb
, int size
)
97 if (set_blocksize(sb
->s_bdev
, size
))
99 /* If we get here, we know size is power of two
100 * and it's value is between 512 and PAGE_SIZE */
101 sb
->s_blocksize
= size
;
102 sb
->s_blocksize_bits
= blksize_bits(size
);
103 return sb
->s_blocksize
;
106 EXPORT_SYMBOL(sb_set_blocksize
);
108 int sb_min_blocksize(struct super_block
*sb
, int size
)
110 int minsize
= bdev_logical_block_size(sb
->s_bdev
);
113 return sb_set_blocksize(sb
, size
);
116 EXPORT_SYMBOL(sb_min_blocksize
);
119 blkdev_get_block(struct inode
*inode
, sector_t iblock
,
120 struct buffer_head
*bh
, int create
)
122 if (iblock
>= max_block(I_BDEV(inode
))) {
127 * for reads, we're just trying to fill a partial page.
128 * return a hole, they will have to call get_block again
129 * before they can fill it, and they will get -EIO at that
134 bh
->b_bdev
= I_BDEV(inode
);
135 bh
->b_blocknr
= iblock
;
136 set_buffer_mapped(bh
);
141 blkdev_get_blocks(struct inode
*inode
, sector_t iblock
,
142 struct buffer_head
*bh
, int create
)
144 sector_t end_block
= max_block(I_BDEV(inode
));
145 unsigned long max_blocks
= bh
->b_size
>> inode
->i_blkbits
;
147 if ((iblock
+ max_blocks
) > end_block
) {
148 max_blocks
= end_block
- iblock
;
149 if ((long)max_blocks
<= 0) {
151 return -EIO
; /* write fully beyond EOF */
153 * It is a read which is fully beyond EOF. We return
154 * a !buffer_mapped buffer
160 bh
->b_bdev
= I_BDEV(inode
);
161 bh
->b_blocknr
= iblock
;
162 bh
->b_size
= max_blocks
<< inode
->i_blkbits
;
164 set_buffer_mapped(bh
);
169 blkdev_direct_IO(int rw
, struct kiocb
*iocb
, const struct iovec
*iov
,
170 loff_t offset
, unsigned long nr_segs
)
172 struct file
*file
= iocb
->ki_filp
;
173 struct inode
*inode
= file
->f_mapping
->host
;
175 return blockdev_direct_IO_no_locking(rw
, iocb
, inode
, I_BDEV(inode
),
176 iov
, offset
, nr_segs
, blkdev_get_blocks
, NULL
);
179 int __sync_blockdev(struct block_device
*bdev
, int wait
)
184 return filemap_flush(bdev
->bd_inode
->i_mapping
);
185 return filemap_write_and_wait(bdev
->bd_inode
->i_mapping
);
189 * Write out and wait upon all the dirty data associated with a block
190 * device via its mapping. Does not take the superblock lock.
192 int sync_blockdev(struct block_device
*bdev
)
194 return __sync_blockdev(bdev
, 1);
196 EXPORT_SYMBOL(sync_blockdev
);
199 * Write out and wait upon all dirty data associated with this
200 * device. Filesystem data as well as the underlying block
201 * device. Takes the superblock lock.
203 int fsync_bdev(struct block_device
*bdev
)
205 struct super_block
*sb
= get_super(bdev
);
207 int res
= sync_filesystem(sb
);
211 return sync_blockdev(bdev
);
213 EXPORT_SYMBOL(fsync_bdev
);
216 * freeze_bdev -- lock a filesystem and force it into a consistent state
217 * @bdev: blockdevice to lock
219 * If a superblock is found on this device, we take the s_umount semaphore
220 * on it to make sure nobody unmounts until the snapshot creation is done.
221 * The reference counter (bd_fsfreeze_count) guarantees that only the last
222 * unfreeze process can unfreeze the frozen filesystem actually when multiple
223 * freeze requests arrive simultaneously. It counts up in freeze_bdev() and
224 * count down in thaw_bdev(). When it becomes 0, thaw_bdev() will unfreeze
227 struct super_block
*freeze_bdev(struct block_device
*bdev
)
229 struct super_block
*sb
;
232 mutex_lock(&bdev
->bd_fsfreeze_mutex
);
233 if (bdev
->bd_fsfreeze_count
> 0) {
234 bdev
->bd_fsfreeze_count
++;
235 sb
= get_super(bdev
);
236 mutex_unlock(&bdev
->bd_fsfreeze_mutex
);
239 bdev
->bd_fsfreeze_count
++;
241 sb
= get_super(bdev
);
242 if (sb
&& !(sb
->s_flags
& MS_RDONLY
)) {
243 sb
->s_frozen
= SB_FREEZE_WRITE
;
248 sb
->s_frozen
= SB_FREEZE_TRANS
;
251 sync_blockdev(sb
->s_bdev
);
253 if (sb
->s_op
->freeze_fs
) {
254 error
= sb
->s_op
->freeze_fs(sb
);
257 "VFS:Filesystem freeze failed\n");
258 sb
->s_frozen
= SB_UNFROZEN
;
260 bdev
->bd_fsfreeze_count
--;
261 mutex_unlock(&bdev
->bd_fsfreeze_mutex
);
262 return ERR_PTR(error
);
268 mutex_unlock(&bdev
->bd_fsfreeze_mutex
);
270 return sb
; /* thaw_bdev releases s->s_umount */
272 EXPORT_SYMBOL(freeze_bdev
);
275 * thaw_bdev -- unlock filesystem
276 * @bdev: blockdevice to unlock
277 * @sb: associated superblock
279 * Unlocks the filesystem and marks it writeable again after freeze_bdev().
281 int thaw_bdev(struct block_device
*bdev
, struct super_block
*sb
)
285 mutex_lock(&bdev
->bd_fsfreeze_mutex
);
286 if (!bdev
->bd_fsfreeze_count
) {
287 mutex_unlock(&bdev
->bd_fsfreeze_mutex
);
291 bdev
->bd_fsfreeze_count
--;
292 if (bdev
->bd_fsfreeze_count
> 0) {
295 mutex_unlock(&bdev
->bd_fsfreeze_mutex
);
300 BUG_ON(sb
->s_bdev
!= bdev
);
301 if (!(sb
->s_flags
& MS_RDONLY
)) {
302 if (sb
->s_op
->unfreeze_fs
) {
303 error
= sb
->s_op
->unfreeze_fs(sb
);
306 "VFS:Filesystem thaw failed\n");
307 sb
->s_frozen
= SB_FREEZE_TRANS
;
308 bdev
->bd_fsfreeze_count
++;
309 mutex_unlock(&bdev
->bd_fsfreeze_mutex
);
313 sb
->s_frozen
= SB_UNFROZEN
;
315 wake_up(&sb
->s_wait_unfrozen
);
320 mutex_unlock(&bdev
->bd_fsfreeze_mutex
);
323 EXPORT_SYMBOL(thaw_bdev
);
325 static int blkdev_writepage(struct page
*page
, struct writeback_control
*wbc
)
327 return block_write_full_page(page
, blkdev_get_block
, wbc
);
330 static int blkdev_readpage(struct file
* file
, struct page
* page
)
332 return block_read_full_page(page
, blkdev_get_block
);
335 static int blkdev_write_begin(struct file
*file
, struct address_space
*mapping
,
336 loff_t pos
, unsigned len
, unsigned flags
,
337 struct page
**pagep
, void **fsdata
)
340 return block_write_begin(file
, mapping
, pos
, len
, flags
, pagep
, fsdata
,
344 static int blkdev_write_end(struct file
*file
, struct address_space
*mapping
,
345 loff_t pos
, unsigned len
, unsigned copied
,
346 struct page
*page
, void *fsdata
)
349 ret
= block_write_end(file
, mapping
, pos
, len
, copied
, page
, fsdata
);
352 page_cache_release(page
);
359 * for a block special file file->f_path.dentry->d_inode->i_size is zero
360 * so we compute the size by hand (just as in block_read/write above)
362 static loff_t
block_llseek(struct file
*file
, loff_t offset
, int origin
)
364 struct inode
*bd_inode
= file
->f_mapping
->host
;
368 mutex_lock(&bd_inode
->i_mutex
);
369 size
= i_size_read(bd_inode
);
376 offset
+= file
->f_pos
;
379 if (offset
>= 0 && offset
<= size
) {
380 if (offset
!= file
->f_pos
) {
381 file
->f_pos
= offset
;
385 mutex_unlock(&bd_inode
->i_mutex
);
390 * Filp is never NULL; the only case when ->fsync() is called with
391 * NULL first argument is nfsd_sync_dir() and that's not a directory.
394 static int block_fsync(struct file
*filp
, struct dentry
*dentry
, int datasync
)
396 return sync_blockdev(I_BDEV(filp
->f_mapping
->host
));
403 static __cacheline_aligned_in_smp
DEFINE_SPINLOCK(bdev_lock
);
404 static struct kmem_cache
* bdev_cachep __read_mostly
;
406 static struct inode
*bdev_alloc_inode(struct super_block
*sb
)
408 struct bdev_inode
*ei
= kmem_cache_alloc(bdev_cachep
, GFP_KERNEL
);
411 return &ei
->vfs_inode
;
414 static void bdev_destroy_inode(struct inode
*inode
)
416 struct bdev_inode
*bdi
= BDEV_I(inode
);
418 kmem_cache_free(bdev_cachep
, bdi
);
421 static void init_once(void *foo
)
423 struct bdev_inode
*ei
= (struct bdev_inode
*) foo
;
424 struct block_device
*bdev
= &ei
->bdev
;
426 memset(bdev
, 0, sizeof(*bdev
));
427 mutex_init(&bdev
->bd_mutex
);
428 INIT_LIST_HEAD(&bdev
->bd_inodes
);
429 INIT_LIST_HEAD(&bdev
->bd_list
);
431 INIT_LIST_HEAD(&bdev
->bd_holder_list
);
433 inode_init_once(&ei
->vfs_inode
);
434 /* Initialize mutex for freeze. */
435 mutex_init(&bdev
->bd_fsfreeze_mutex
);
438 static inline void __bd_forget(struct inode
*inode
)
440 list_del_init(&inode
->i_devices
);
441 inode
->i_bdev
= NULL
;
442 inode
->i_mapping
= &inode
->i_data
;
445 static void bdev_clear_inode(struct inode
*inode
)
447 struct block_device
*bdev
= &BDEV_I(inode
)->bdev
;
449 spin_lock(&bdev_lock
);
450 while ( (p
= bdev
->bd_inodes
.next
) != &bdev
->bd_inodes
) {
451 __bd_forget(list_entry(p
, struct inode
, i_devices
));
453 list_del_init(&bdev
->bd_list
);
454 spin_unlock(&bdev_lock
);
457 static const struct super_operations bdev_sops
= {
458 .statfs
= simple_statfs
,
459 .alloc_inode
= bdev_alloc_inode
,
460 .destroy_inode
= bdev_destroy_inode
,
461 .drop_inode
= generic_delete_inode
,
462 .clear_inode
= bdev_clear_inode
,
465 static int bd_get_sb(struct file_system_type
*fs_type
,
466 int flags
, const char *dev_name
, void *data
, struct vfsmount
*mnt
)
468 return get_sb_pseudo(fs_type
, "bdev:", &bdev_sops
, 0x62646576, mnt
);
471 static struct file_system_type bd_type
= {
474 .kill_sb
= kill_anon_super
,
477 struct super_block
*blockdev_superblock __read_mostly
;
479 void __init
bdev_cache_init(void)
482 struct vfsmount
*bd_mnt
;
484 bdev_cachep
= kmem_cache_create("bdev_cache", sizeof(struct bdev_inode
),
485 0, (SLAB_HWCACHE_ALIGN
|SLAB_RECLAIM_ACCOUNT
|
486 SLAB_MEM_SPREAD
|SLAB_PANIC
),
488 err
= register_filesystem(&bd_type
);
490 panic("Cannot register bdev pseudo-fs");
491 bd_mnt
= kern_mount(&bd_type
);
493 panic("Cannot create bdev pseudo-fs");
495 * This vfsmount structure is only used to obtain the
496 * blockdev_superblock, so tell kmemleak not to report it.
498 kmemleak_not_leak(bd_mnt
);
499 blockdev_superblock
= bd_mnt
->mnt_sb
; /* For writeback */
503 * Most likely _very_ bad one - but then it's hardly critical for small
504 * /dev and can be fixed when somebody will need really large one.
505 * Keep in mind that it will be fed through icache hash function too.
507 static inline unsigned long hash(dev_t dev
)
509 return MAJOR(dev
)+MINOR(dev
);
512 static int bdev_test(struct inode
*inode
, void *data
)
514 return BDEV_I(inode
)->bdev
.bd_dev
== *(dev_t
*)data
;
517 static int bdev_set(struct inode
*inode
, void *data
)
519 BDEV_I(inode
)->bdev
.bd_dev
= *(dev_t
*)data
;
523 static LIST_HEAD(all_bdevs
);
525 struct block_device
*bdget(dev_t dev
)
527 struct block_device
*bdev
;
530 inode
= iget5_locked(blockdev_superblock
, hash(dev
),
531 bdev_test
, bdev_set
, &dev
);
536 bdev
= &BDEV_I(inode
)->bdev
;
538 if (inode
->i_state
& I_NEW
) {
539 bdev
->bd_contains
= NULL
;
540 bdev
->bd_inode
= inode
;
541 bdev
->bd_block_size
= (1 << inode
->i_blkbits
);
542 bdev
->bd_part_count
= 0;
543 bdev
->bd_invalidated
= 0;
544 inode
->i_mode
= S_IFBLK
;
546 inode
->i_bdev
= bdev
;
547 inode
->i_data
.a_ops
= &def_blk_aops
;
548 mapping_set_gfp_mask(&inode
->i_data
, GFP_USER
);
549 inode
->i_data
.backing_dev_info
= &default_backing_dev_info
;
550 spin_lock(&bdev_lock
);
551 list_add(&bdev
->bd_list
, &all_bdevs
);
552 spin_unlock(&bdev_lock
);
553 unlock_new_inode(inode
);
558 EXPORT_SYMBOL(bdget
);
561 * bdgrab -- Grab a reference to an already referenced block device
562 * @bdev: Block device to grab a reference to.
564 struct block_device
*bdgrab(struct block_device
*bdev
)
566 atomic_inc(&bdev
->bd_inode
->i_count
);
570 long nr_blockdev_pages(void)
572 struct block_device
*bdev
;
574 spin_lock(&bdev_lock
);
575 list_for_each_entry(bdev
, &all_bdevs
, bd_list
) {
576 ret
+= bdev
->bd_inode
->i_mapping
->nrpages
;
578 spin_unlock(&bdev_lock
);
582 void bdput(struct block_device
*bdev
)
584 iput(bdev
->bd_inode
);
587 EXPORT_SYMBOL(bdput
);
589 static struct block_device
*bd_acquire(struct inode
*inode
)
591 struct block_device
*bdev
;
593 spin_lock(&bdev_lock
);
594 bdev
= inode
->i_bdev
;
596 atomic_inc(&bdev
->bd_inode
->i_count
);
597 spin_unlock(&bdev_lock
);
600 spin_unlock(&bdev_lock
);
602 bdev
= bdget(inode
->i_rdev
);
604 spin_lock(&bdev_lock
);
605 if (!inode
->i_bdev
) {
607 * We take an additional bd_inode->i_count for inode,
608 * and it's released in clear_inode() of inode.
609 * So, we can access it via ->i_mapping always
612 atomic_inc(&bdev
->bd_inode
->i_count
);
613 inode
->i_bdev
= bdev
;
614 inode
->i_mapping
= bdev
->bd_inode
->i_mapping
;
615 list_add(&inode
->i_devices
, &bdev
->bd_inodes
);
617 spin_unlock(&bdev_lock
);
622 /* Call when you free inode */
624 void bd_forget(struct inode
*inode
)
626 struct block_device
*bdev
= NULL
;
628 spin_lock(&bdev_lock
);
630 if (!sb_is_blkdev_sb(inode
->i_sb
))
631 bdev
= inode
->i_bdev
;
634 spin_unlock(&bdev_lock
);
637 iput(bdev
->bd_inode
);
640 int bd_claim(struct block_device
*bdev
, void *holder
)
643 spin_lock(&bdev_lock
);
645 /* first decide result */
646 if (bdev
->bd_holder
== holder
)
647 res
= 0; /* already a holder */
648 else if (bdev
->bd_holder
!= NULL
)
649 res
= -EBUSY
; /* held by someone else */
650 else if (bdev
->bd_contains
== bdev
)
651 res
= 0; /* is a whole device which isn't held */
653 else if (bdev
->bd_contains
->bd_holder
== bd_claim
)
654 res
= 0; /* is a partition of a device that is being partitioned */
655 else if (bdev
->bd_contains
->bd_holder
!= NULL
)
656 res
= -EBUSY
; /* is a partition of a held device */
658 res
= 0; /* is a partition of an un-held device */
660 /* now impose change */
662 /* note that for a whole device bd_holders
663 * will be incremented twice, and bd_holder will
664 * be set to bd_claim before being set to holder
666 bdev
->bd_contains
->bd_holders
++;
667 bdev
->bd_contains
->bd_holder
= bd_claim
;
669 bdev
->bd_holder
= holder
;
671 spin_unlock(&bdev_lock
);
675 EXPORT_SYMBOL(bd_claim
);
677 void bd_release(struct block_device
*bdev
)
679 spin_lock(&bdev_lock
);
680 if (!--bdev
->bd_contains
->bd_holders
)
681 bdev
->bd_contains
->bd_holder
= NULL
;
682 if (!--bdev
->bd_holders
)
683 bdev
->bd_holder
= NULL
;
684 spin_unlock(&bdev_lock
);
687 EXPORT_SYMBOL(bd_release
);
691 * Functions for bd_claim_by_kobject / bd_release_from_kobject
693 * If a kobject is passed to bd_claim_by_kobject()
694 * and the kobject has a parent directory,
695 * following symlinks are created:
696 * o from the kobject to the claimed bdev
697 * o from "holders" directory of the bdev to the parent of the kobject
698 * bd_release_from_kobject() removes these symlinks.
701 * If /dev/dm-0 maps to /dev/sda, kobject corresponding to
702 * /sys/block/dm-0/slaves is passed to bd_claim_by_kobject(), then:
703 * /sys/block/dm-0/slaves/sda --> /sys/block/sda
704 * /sys/block/sda/holders/dm-0 --> /sys/block/dm-0
707 static int add_symlink(struct kobject
*from
, struct kobject
*to
)
711 return sysfs_create_link(from
, to
, kobject_name(to
));
714 static void del_symlink(struct kobject
*from
, struct kobject
*to
)
718 sysfs_remove_link(from
, kobject_name(to
));
722 * 'struct bd_holder' contains pointers to kobjects symlinked by
723 * bd_claim_by_kobject.
724 * It's connected to bd_holder_list which is protected by bdev->bd_sem.
727 struct list_head list
; /* chain of holders of the bdev */
728 int count
; /* references from the holder */
729 struct kobject
*sdir
; /* holder object, e.g. "/block/dm-0/slaves" */
730 struct kobject
*hdev
; /* e.g. "/block/dm-0" */
731 struct kobject
*hdir
; /* e.g. "/block/sda/holders" */
732 struct kobject
*sdev
; /* e.g. "/block/sda" */
736 * Get references of related kobjects at once.
737 * Returns 1 on success. 0 on failure.
739 * Should call bd_holder_release_dirs() after successful use.
741 static int bd_holder_grab_dirs(struct block_device
*bdev
,
742 struct bd_holder
*bo
)
747 bo
->sdir
= kobject_get(bo
->sdir
);
751 bo
->hdev
= kobject_get(bo
->sdir
->parent
);
755 bo
->sdev
= kobject_get(&part_to_dev(bdev
->bd_part
)->kobj
);
759 bo
->hdir
= kobject_get(bdev
->bd_part
->holder_dir
);
766 kobject_put(bo
->sdev
);
768 kobject_put(bo
->hdev
);
770 kobject_put(bo
->sdir
);
775 /* Put references of related kobjects at once. */
776 static void bd_holder_release_dirs(struct bd_holder
*bo
)
778 kobject_put(bo
->hdir
);
779 kobject_put(bo
->sdev
);
780 kobject_put(bo
->hdev
);
781 kobject_put(bo
->sdir
);
784 static struct bd_holder
*alloc_bd_holder(struct kobject
*kobj
)
786 struct bd_holder
*bo
;
788 bo
= kzalloc(sizeof(*bo
), GFP_KERNEL
);
798 static void free_bd_holder(struct bd_holder
*bo
)
804 * find_bd_holder - find matching struct bd_holder from the block device
806 * @bdev: struct block device to be searched
807 * @bo: target struct bd_holder
809 * Returns matching entry with @bo in @bdev->bd_holder_list.
810 * If found, increment the reference count and return the pointer.
811 * If not found, returns NULL.
813 static struct bd_holder
*find_bd_holder(struct block_device
*bdev
,
814 struct bd_holder
*bo
)
816 struct bd_holder
*tmp
;
818 list_for_each_entry(tmp
, &bdev
->bd_holder_list
, list
)
819 if (tmp
->sdir
== bo
->sdir
) {
828 * add_bd_holder - create sysfs symlinks for bd_claim() relationship
830 * @bdev: block device to be bd_claimed
831 * @bo: preallocated and initialized by alloc_bd_holder()
833 * Add @bo to @bdev->bd_holder_list, create symlinks.
835 * Returns 0 if symlinks are created.
836 * Returns -ve if something fails.
838 static int add_bd_holder(struct block_device
*bdev
, struct bd_holder
*bo
)
845 if (!bd_holder_grab_dirs(bdev
, bo
))
848 err
= add_symlink(bo
->sdir
, bo
->sdev
);
852 err
= add_symlink(bo
->hdir
, bo
->hdev
);
854 del_symlink(bo
->sdir
, bo
->sdev
);
858 list_add_tail(&bo
->list
, &bdev
->bd_holder_list
);
863 * del_bd_holder - delete sysfs symlinks for bd_claim() relationship
865 * @bdev: block device to be bd_claimed
866 * @kobj: holder's kobject
868 * If there is matching entry with @kobj in @bdev->bd_holder_list
869 * and no other bd_claim() from the same kobject,
870 * remove the struct bd_holder from the list, delete symlinks for it.
872 * Returns a pointer to the struct bd_holder when it's removed from the list
873 * and ready to be freed.
874 * Returns NULL if matching claim isn't found or there is other bd_claim()
875 * by the same kobject.
877 static struct bd_holder
*del_bd_holder(struct block_device
*bdev
,
878 struct kobject
*kobj
)
880 struct bd_holder
*bo
;
882 list_for_each_entry(bo
, &bdev
->bd_holder_list
, list
) {
883 if (bo
->sdir
== kobj
) {
885 BUG_ON(bo
->count
< 0);
888 del_symlink(bo
->sdir
, bo
->sdev
);
889 del_symlink(bo
->hdir
, bo
->hdev
);
890 bd_holder_release_dirs(bo
);
901 * bd_claim_by_kobject - bd_claim() with additional kobject signature
903 * @bdev: block device to be claimed
904 * @holder: holder's signature
905 * @kobj: holder's kobject
907 * Do bd_claim() and if it succeeds, create sysfs symlinks between
908 * the bdev and the holder's kobject.
909 * Use bd_release_from_kobject() when relesing the claimed bdev.
911 * Returns 0 on success. (same as bd_claim())
912 * Returns errno on failure.
914 static int bd_claim_by_kobject(struct block_device
*bdev
, void *holder
,
915 struct kobject
*kobj
)
918 struct bd_holder
*bo
, *found
;
923 bo
= alloc_bd_holder(kobj
);
927 mutex_lock(&bdev
->bd_mutex
);
929 err
= bd_claim(bdev
, holder
);
933 found
= find_bd_holder(bdev
, bo
);
937 err
= add_bd_holder(bdev
, bo
);
943 mutex_unlock(&bdev
->bd_mutex
);
949 * bd_release_from_kobject - bd_release() with additional kobject signature
951 * @bdev: block device to be released
952 * @kobj: holder's kobject
954 * Do bd_release() and remove sysfs symlinks created by bd_claim_by_kobject().
956 static void bd_release_from_kobject(struct block_device
*bdev
,
957 struct kobject
*kobj
)
962 mutex_lock(&bdev
->bd_mutex
);
964 free_bd_holder(del_bd_holder(bdev
, kobj
));
965 mutex_unlock(&bdev
->bd_mutex
);
969 * bd_claim_by_disk - wrapper function for bd_claim_by_kobject()
971 * @bdev: block device to be claimed
972 * @holder: holder's signature
973 * @disk: holder's gendisk
975 * Call bd_claim_by_kobject() with getting @disk->slave_dir.
977 int bd_claim_by_disk(struct block_device
*bdev
, void *holder
,
978 struct gendisk
*disk
)
980 return bd_claim_by_kobject(bdev
, holder
, kobject_get(disk
->slave_dir
));
982 EXPORT_SYMBOL_GPL(bd_claim_by_disk
);
985 * bd_release_from_disk - wrapper function for bd_release_from_kobject()
987 * @bdev: block device to be claimed
988 * @disk: holder's gendisk
990 * Call bd_release_from_kobject() and put @disk->slave_dir.
992 void bd_release_from_disk(struct block_device
*bdev
, struct gendisk
*disk
)
994 bd_release_from_kobject(bdev
, disk
->slave_dir
);
995 kobject_put(disk
->slave_dir
);
997 EXPORT_SYMBOL_GPL(bd_release_from_disk
);
1001 * Tries to open block device by device number. Use it ONLY if you
1002 * really do not have anything better - i.e. when you are behind a
1003 * truly sucky interface and all you are given is a device number. _Never_
1004 * to be used for internal purposes. If you ever need it - reconsider
1007 struct block_device
*open_by_devnum(dev_t dev
, fmode_t mode
)
1009 struct block_device
*bdev
= bdget(dev
);
1012 err
= blkdev_get(bdev
, mode
);
1013 return err
? ERR_PTR(err
) : bdev
;
1016 EXPORT_SYMBOL(open_by_devnum
);
1019 * flush_disk - invalidates all buffer-cache entries on a disk
1021 * @bdev: struct block device to be flushed
1023 * Invalidates all buffer-cache entries on a disk. It should be called
1024 * when a disk has been changed -- either by a media change or online
1027 static void flush_disk(struct block_device
*bdev
)
1029 if (__invalidate_device(bdev
)) {
1030 char name
[BDEVNAME_SIZE
] = "";
1033 disk_name(bdev
->bd_disk
, 0, name
);
1034 printk(KERN_WARNING
"VFS: busy inodes on changed media or "
1035 "resized disk %s\n", name
);
1040 if (disk_partitionable(bdev
->bd_disk
))
1041 bdev
->bd_invalidated
= 1;
1045 * check_disk_size_change - checks for disk size change and adjusts bdev size.
1046 * @disk: struct gendisk to check
1047 * @bdev: struct bdev to adjust.
1049 * This routine checks to see if the bdev size does not match the disk size
1050 * and adjusts it if it differs.
1052 void check_disk_size_change(struct gendisk
*disk
, struct block_device
*bdev
)
1054 loff_t disk_size
, bdev_size
;
1056 disk_size
= (loff_t
)get_capacity(disk
) << 9;
1057 bdev_size
= i_size_read(bdev
->bd_inode
);
1058 if (disk_size
!= bdev_size
) {
1059 char name
[BDEVNAME_SIZE
];
1061 disk_name(disk
, 0, name
);
1063 "%s: detected capacity change from %lld to %lld\n",
1064 name
, bdev_size
, disk_size
);
1065 i_size_write(bdev
->bd_inode
, disk_size
);
1069 EXPORT_SYMBOL(check_disk_size_change
);
1072 * revalidate_disk - wrapper for lower-level driver's revalidate_disk call-back
1073 * @disk: struct gendisk to be revalidated
1075 * This routine is a wrapper for lower-level driver's revalidate_disk
1076 * call-backs. It is used to do common pre and post operations needed
1077 * for all revalidate_disk operations.
1079 int revalidate_disk(struct gendisk
*disk
)
1081 struct block_device
*bdev
;
1084 if (disk
->fops
->revalidate_disk
)
1085 ret
= disk
->fops
->revalidate_disk(disk
);
1087 bdev
= bdget_disk(disk
, 0);
1091 mutex_lock(&bdev
->bd_mutex
);
1092 check_disk_size_change(disk
, bdev
);
1093 mutex_unlock(&bdev
->bd_mutex
);
1097 EXPORT_SYMBOL(revalidate_disk
);
1100 * This routine checks whether a removable media has been changed,
1101 * and invalidates all buffer-cache-entries in that case. This
1102 * is a relatively slow routine, so we have to try to minimize using
1103 * it. Thus it is called only upon a 'mount' or 'open'. This
1104 * is the best way of combining speed and utility, I think.
1105 * People changing diskettes in the middle of an operation deserve
1108 int check_disk_change(struct block_device
*bdev
)
1110 struct gendisk
*disk
= bdev
->bd_disk
;
1111 const struct block_device_operations
*bdops
= disk
->fops
;
1113 if (!bdops
->media_changed
)
1115 if (!bdops
->media_changed(bdev
->bd_disk
))
1119 if (bdops
->revalidate_disk
)
1120 bdops
->revalidate_disk(bdev
->bd_disk
);
1124 EXPORT_SYMBOL(check_disk_change
);
1126 void bd_set_size(struct block_device
*bdev
, loff_t size
)
1128 unsigned bsize
= bdev_logical_block_size(bdev
);
1130 bdev
->bd_inode
->i_size
= size
;
1131 while (bsize
< PAGE_CACHE_SIZE
) {
1136 bdev
->bd_block_size
= bsize
;
1137 bdev
->bd_inode
->i_blkbits
= blksize_bits(bsize
);
1139 EXPORT_SYMBOL(bd_set_size
);
1141 static int __blkdev_put(struct block_device
*bdev
, fmode_t mode
, int for_part
);
1146 * mutex_lock(part->bd_mutex)
1147 * mutex_lock_nested(whole->bd_mutex, 1)
1150 static int __blkdev_get(struct block_device
*bdev
, fmode_t mode
, int for_part
)
1152 struct gendisk
*disk
;
1157 if (mode
& FMODE_READ
)
1159 if (mode
& FMODE_WRITE
)
1162 * hooks: /n/, see "layering violations".
1164 ret
= devcgroup_inode_permission(bdev
->bd_inode
, perm
);
1174 disk
= get_gendisk(bdev
->bd_dev
, &partno
);
1176 goto out_unlock_kernel
;
1178 mutex_lock_nested(&bdev
->bd_mutex
, for_part
);
1179 if (!bdev
->bd_openers
) {
1180 bdev
->bd_disk
= disk
;
1181 bdev
->bd_contains
= bdev
;
1183 struct backing_dev_info
*bdi
;
1186 bdev
->bd_part
= disk_get_part(disk
, partno
);
1190 if (disk
->fops
->open
) {
1191 ret
= disk
->fops
->open(bdev
, mode
);
1192 if (ret
== -ERESTARTSYS
) {
1193 /* Lost a race with 'disk' being
1194 * deleted, try again.
1197 disk_put_part(bdev
->bd_part
);
1198 bdev
->bd_part
= NULL
;
1199 module_put(disk
->fops
->owner
);
1201 bdev
->bd_disk
= NULL
;
1202 mutex_unlock(&bdev
->bd_mutex
);
1208 if (!bdev
->bd_openers
) {
1209 bd_set_size(bdev
,(loff_t
)get_capacity(disk
)<<9);
1210 bdi
= blk_get_backing_dev_info(bdev
);
1212 bdi
= &default_backing_dev_info
;
1213 bdev
->bd_inode
->i_data
.backing_dev_info
= bdi
;
1215 if (bdev
->bd_invalidated
)
1216 rescan_partitions(disk
, bdev
);
1218 struct block_device
*whole
;
1219 whole
= bdget_disk(disk
, 0);
1224 ret
= __blkdev_get(whole
, mode
, 1);
1227 bdev
->bd_contains
= whole
;
1228 bdev
->bd_inode
->i_data
.backing_dev_info
=
1229 whole
->bd_inode
->i_data
.backing_dev_info
;
1230 bdev
->bd_part
= disk_get_part(disk
, partno
);
1231 if (!(disk
->flags
& GENHD_FL_UP
) ||
1232 !bdev
->bd_part
|| !bdev
->bd_part
->nr_sects
) {
1236 bd_set_size(bdev
, (loff_t
)bdev
->bd_part
->nr_sects
<< 9);
1240 module_put(disk
->fops
->owner
);
1242 if (bdev
->bd_contains
== bdev
) {
1243 if (bdev
->bd_disk
->fops
->open
) {
1244 ret
= bdev
->bd_disk
->fops
->open(bdev
, mode
);
1246 goto out_unlock_bdev
;
1248 if (bdev
->bd_invalidated
)
1249 rescan_partitions(bdev
->bd_disk
, bdev
);
1254 bdev
->bd_part_count
++;
1255 mutex_unlock(&bdev
->bd_mutex
);
1260 disk_put_part(bdev
->bd_part
);
1261 bdev
->bd_disk
= NULL
;
1262 bdev
->bd_part
= NULL
;
1263 bdev
->bd_inode
->i_data
.backing_dev_info
= &default_backing_dev_info
;
1264 if (bdev
!= bdev
->bd_contains
)
1265 __blkdev_put(bdev
->bd_contains
, mode
, 1);
1266 bdev
->bd_contains
= NULL
;
1268 mutex_unlock(&bdev
->bd_mutex
);
1273 module_put(disk
->fops
->owner
);
1280 int blkdev_get(struct block_device
*bdev
, fmode_t mode
)
1282 return __blkdev_get(bdev
, mode
, 0);
1284 EXPORT_SYMBOL(blkdev_get
);
1286 static int blkdev_open(struct inode
* inode
, struct file
* filp
)
1288 struct block_device
*bdev
;
1292 * Preserve backwards compatibility and allow large file access
1293 * even if userspace doesn't ask for it explicitly. Some mkfs
1294 * binary needs it. We might want to drop this workaround
1295 * during an unstable branch.
1297 filp
->f_flags
|= O_LARGEFILE
;
1299 if (filp
->f_flags
& O_NDELAY
)
1300 filp
->f_mode
|= FMODE_NDELAY
;
1301 if (filp
->f_flags
& O_EXCL
)
1302 filp
->f_mode
|= FMODE_EXCL
;
1303 if ((filp
->f_flags
& O_ACCMODE
) == 3)
1304 filp
->f_mode
|= FMODE_WRITE_IOCTL
;
1306 bdev
= bd_acquire(inode
);
1310 filp
->f_mapping
= bdev
->bd_inode
->i_mapping
;
1312 res
= blkdev_get(bdev
, filp
->f_mode
);
1316 if (filp
->f_mode
& FMODE_EXCL
) {
1317 res
= bd_claim(bdev
, filp
);
1319 goto out_blkdev_put
;
1325 blkdev_put(bdev
, filp
->f_mode
);
1329 static int __blkdev_put(struct block_device
*bdev
, fmode_t mode
, int for_part
)
1332 struct gendisk
*disk
= bdev
->bd_disk
;
1333 struct block_device
*victim
= NULL
;
1335 mutex_lock_nested(&bdev
->bd_mutex
, for_part
);
1338 bdev
->bd_part_count
--;
1340 if (!--bdev
->bd_openers
) {
1341 sync_blockdev(bdev
);
1344 if (bdev
->bd_contains
== bdev
) {
1345 if (disk
->fops
->release
)
1346 ret
= disk
->fops
->release(disk
, mode
);
1348 if (!bdev
->bd_openers
) {
1349 struct module
*owner
= disk
->fops
->owner
;
1353 disk_put_part(bdev
->bd_part
);
1354 bdev
->bd_part
= NULL
;
1355 bdev
->bd_disk
= NULL
;
1356 bdev
->bd_inode
->i_data
.backing_dev_info
= &default_backing_dev_info
;
1357 if (bdev
!= bdev
->bd_contains
)
1358 victim
= bdev
->bd_contains
;
1359 bdev
->bd_contains
= NULL
;
1362 mutex_unlock(&bdev
->bd_mutex
);
1365 __blkdev_put(victim
, mode
, 1);
1369 int blkdev_put(struct block_device
*bdev
, fmode_t mode
)
1371 return __blkdev_put(bdev
, mode
, 0);
1373 EXPORT_SYMBOL(blkdev_put
);
1375 static int blkdev_close(struct inode
* inode
, struct file
* filp
)
1377 struct block_device
*bdev
= I_BDEV(filp
->f_mapping
->host
);
1378 if (bdev
->bd_holder
== filp
)
1380 return blkdev_put(bdev
, filp
->f_mode
);
1383 static long block_ioctl(struct file
*file
, unsigned cmd
, unsigned long arg
)
1385 struct block_device
*bdev
= I_BDEV(file
->f_mapping
->host
);
1386 fmode_t mode
= file
->f_mode
;
1389 * O_NDELAY can be altered using fcntl(.., F_SETFL, ..), so we have
1390 * to updated it before every ioctl.
1392 if (file
->f_flags
& O_NDELAY
)
1393 mode
|= FMODE_NDELAY
;
1395 mode
&= ~FMODE_NDELAY
;
1397 return blkdev_ioctl(bdev
, mode
, cmd
, arg
);
1401 * Write data to the block device. Only intended for the block device itself
1402 * and the raw driver which basically is a fake block device.
1404 * Does not take i_mutex for the write and thus is not for general purpose
1407 ssize_t
blkdev_aio_write(struct kiocb
*iocb
, const struct iovec
*iov
,
1408 unsigned long nr_segs
, loff_t pos
)
1410 struct file
*file
= iocb
->ki_filp
;
1413 BUG_ON(iocb
->ki_pos
!= pos
);
1415 ret
= __generic_file_aio_write(iocb
, iov
, nr_segs
, &iocb
->ki_pos
);
1416 if (ret
> 0 || ret
== -EIOCBQUEUED
) {
1419 err
= generic_write_sync(file
, pos
, ret
);
1420 if (err
< 0 && ret
> 0)
1425 EXPORT_SYMBOL_GPL(blkdev_aio_write
);
1428 * Try to release a page associated with block device when the system
1429 * is under memory pressure.
1431 static int blkdev_releasepage(struct page
*page
, gfp_t wait
)
1433 struct super_block
*super
= BDEV_I(page
->mapping
->host
)->bdev
.bd_super
;
1435 if (super
&& super
->s_op
->bdev_try_to_free_page
)
1436 return super
->s_op
->bdev_try_to_free_page(super
, page
, wait
);
1438 return try_to_free_buffers(page
);
1441 static const struct address_space_operations def_blk_aops
= {
1442 .readpage
= blkdev_readpage
,
1443 .writepage
= blkdev_writepage
,
1444 .sync_page
= block_sync_page
,
1445 .write_begin
= blkdev_write_begin
,
1446 .write_end
= blkdev_write_end
,
1447 .writepages
= generic_writepages
,
1448 .releasepage
= blkdev_releasepage
,
1449 .direct_IO
= blkdev_direct_IO
,
1452 const struct file_operations def_blk_fops
= {
1453 .open
= blkdev_open
,
1454 .release
= blkdev_close
,
1455 .llseek
= block_llseek
,
1456 .read
= do_sync_read
,
1457 .write
= do_sync_write
,
1458 .aio_read
= generic_file_aio_read
,
1459 .aio_write
= blkdev_aio_write
,
1460 .mmap
= generic_file_mmap
,
1461 .fsync
= block_fsync
,
1462 .unlocked_ioctl
= block_ioctl
,
1463 #ifdef CONFIG_COMPAT
1464 .compat_ioctl
= compat_blkdev_ioctl
,
1466 .splice_read
= generic_file_splice_read
,
1467 .splice_write
= generic_file_splice_write
,
1470 int ioctl_by_bdev(struct block_device
*bdev
, unsigned cmd
, unsigned long arg
)
1473 mm_segment_t old_fs
= get_fs();
1475 res
= blkdev_ioctl(bdev
, 0, cmd
, arg
);
1480 EXPORT_SYMBOL(ioctl_by_bdev
);
1483 * lookup_bdev - lookup a struct block_device by name
1484 * @pathname: special file representing the block device
1486 * Get a reference to the blockdevice at @pathname in the current
1487 * namespace if possible and return it. Return ERR_PTR(error)
1490 struct block_device
*lookup_bdev(const char *pathname
)
1492 struct block_device
*bdev
;
1493 struct inode
*inode
;
1497 if (!pathname
|| !*pathname
)
1498 return ERR_PTR(-EINVAL
);
1500 error
= kern_path(pathname
, LOOKUP_FOLLOW
, &path
);
1502 return ERR_PTR(error
);
1504 inode
= path
.dentry
->d_inode
;
1506 if (!S_ISBLK(inode
->i_mode
))
1509 if (path
.mnt
->mnt_flags
& MNT_NODEV
)
1512 bdev
= bd_acquire(inode
);
1519 bdev
= ERR_PTR(error
);
1522 EXPORT_SYMBOL(lookup_bdev
);
1525 * open_bdev_exclusive - open a block device by name and set it up for use
1527 * @path: special file representing the block device
1528 * @mode: FMODE_... combination to pass be used
1529 * @holder: owner for exclusion
1531 * Open the blockdevice described by the special file at @path, claim it
1534 struct block_device
*open_bdev_exclusive(const char *path
, fmode_t mode
, void *holder
)
1536 struct block_device
*bdev
;
1539 bdev
= lookup_bdev(path
);
1543 error
= blkdev_get(bdev
, mode
);
1545 return ERR_PTR(error
);
1547 if ((mode
& FMODE_WRITE
) && bdev_read_only(bdev
))
1549 error
= bd_claim(bdev
, holder
);
1556 blkdev_put(bdev
, mode
);
1557 return ERR_PTR(error
);
1560 EXPORT_SYMBOL(open_bdev_exclusive
);
1563 * close_bdev_exclusive - close a blockdevice opened by open_bdev_exclusive()
1565 * @bdev: blockdevice to close
1566 * @mode: mode, must match that used to open.
1568 * This is the counterpart to open_bdev_exclusive().
1570 void close_bdev_exclusive(struct block_device
*bdev
, fmode_t mode
)
1573 blkdev_put(bdev
, mode
);
1576 EXPORT_SYMBOL(close_bdev_exclusive
);
1578 int __invalidate_device(struct block_device
*bdev
)
1580 struct super_block
*sb
= get_super(bdev
);
1585 * no need to lock the super, get_super holds the
1586 * read mutex so the filesystem cannot go away
1587 * under us (->put_super runs with the write lock
1590 shrink_dcache_sb(sb
);
1591 res
= invalidate_inodes(sb
);
1594 invalidate_bdev(bdev
);
1597 EXPORT_SYMBOL(__invalidate_device
);