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 <asm/uaccess.h>
32 struct block_device bdev
;
33 struct inode vfs_inode
;
36 static const struct address_space_operations def_blk_aops
;
38 static inline struct bdev_inode
*BDEV_I(struct inode
*inode
)
40 return container_of(inode
, struct bdev_inode
, vfs_inode
);
43 inline struct block_device
*I_BDEV(struct inode
*inode
)
45 return &BDEV_I(inode
)->bdev
;
48 EXPORT_SYMBOL(I_BDEV
);
50 static sector_t
max_block(struct block_device
*bdev
)
52 sector_t retval
= ~((sector_t
)0);
53 loff_t sz
= i_size_read(bdev
->bd_inode
);
56 unsigned int size
= block_size(bdev
);
57 unsigned int sizebits
= blksize_bits(size
);
58 retval
= (sz
>> sizebits
);
63 /* Kill _all_ buffers and pagecache , dirty or not.. */
64 static void kill_bdev(struct block_device
*bdev
)
66 if (bdev
->bd_inode
->i_mapping
->nrpages
== 0)
69 truncate_inode_pages(bdev
->bd_inode
->i_mapping
, 0);
72 int set_blocksize(struct block_device
*bdev
, int size
)
74 /* Size must be a power of two, and between 512 and PAGE_SIZE */
75 if (size
> PAGE_SIZE
|| size
< 512 || !is_power_of_2(size
))
78 /* Size cannot be smaller than the size supported by the device */
79 if (size
< bdev_logical_block_size(bdev
))
82 /* Don't change the size if it is same as current */
83 if (bdev
->bd_block_size
!= size
) {
85 bdev
->bd_block_size
= size
;
86 bdev
->bd_inode
->i_blkbits
= blksize_bits(size
);
92 EXPORT_SYMBOL(set_blocksize
);
94 int sb_set_blocksize(struct super_block
*sb
, int size
)
96 if (set_blocksize(sb
->s_bdev
, size
))
98 /* If we get here, we know size is power of two
99 * and it's value is between 512 and PAGE_SIZE */
100 sb
->s_blocksize
= size
;
101 sb
->s_blocksize_bits
= blksize_bits(size
);
102 return sb
->s_blocksize
;
105 EXPORT_SYMBOL(sb_set_blocksize
);
107 int sb_min_blocksize(struct super_block
*sb
, int size
)
109 int minsize
= bdev_logical_block_size(sb
->s_bdev
);
112 return sb_set_blocksize(sb
, size
);
115 EXPORT_SYMBOL(sb_min_blocksize
);
118 blkdev_get_block(struct inode
*inode
, sector_t iblock
,
119 struct buffer_head
*bh
, int create
)
121 if (iblock
>= max_block(I_BDEV(inode
))) {
126 * for reads, we're just trying to fill a partial page.
127 * return a hole, they will have to call get_block again
128 * before they can fill it, and they will get -EIO at that
133 bh
->b_bdev
= I_BDEV(inode
);
134 bh
->b_blocknr
= iblock
;
135 set_buffer_mapped(bh
);
140 blkdev_get_blocks(struct inode
*inode
, sector_t iblock
,
141 struct buffer_head
*bh
, int create
)
143 sector_t end_block
= max_block(I_BDEV(inode
));
144 unsigned long max_blocks
= bh
->b_size
>> inode
->i_blkbits
;
146 if ((iblock
+ max_blocks
) > end_block
) {
147 max_blocks
= end_block
- iblock
;
148 if ((long)max_blocks
<= 0) {
150 return -EIO
; /* write fully beyond EOF */
152 * It is a read which is fully beyond EOF. We return
153 * a !buffer_mapped buffer
159 bh
->b_bdev
= I_BDEV(inode
);
160 bh
->b_blocknr
= iblock
;
161 bh
->b_size
= max_blocks
<< inode
->i_blkbits
;
163 set_buffer_mapped(bh
);
168 blkdev_direct_IO(int rw
, struct kiocb
*iocb
, const struct iovec
*iov
,
169 loff_t offset
, unsigned long nr_segs
)
171 struct file
*file
= iocb
->ki_filp
;
172 struct inode
*inode
= file
->f_mapping
->host
;
174 return blockdev_direct_IO_no_locking(rw
, iocb
, inode
, I_BDEV(inode
),
175 iov
, offset
, nr_segs
, blkdev_get_blocks
, NULL
);
179 * Write out and wait upon all the dirty data associated with a block
180 * device via its mapping. Does not take the superblock lock.
182 int sync_blockdev(struct block_device
*bdev
)
187 ret
= filemap_write_and_wait(bdev
->bd_inode
->i_mapping
);
190 EXPORT_SYMBOL(sync_blockdev
);
193 * Write out and wait upon all dirty data associated with this
194 * device. Filesystem data as well as the underlying block
195 * device. Takes the superblock lock.
197 int fsync_bdev(struct block_device
*bdev
)
199 struct super_block
*sb
= get_super(bdev
);
201 int res
= fsync_super(sb
);
205 return sync_blockdev(bdev
);
207 EXPORT_SYMBOL(fsync_bdev
);
210 * freeze_bdev -- lock a filesystem and force it into a consistent state
211 * @bdev: blockdevice to lock
213 * This takes the block device bd_mount_sem to make sure no new mounts
214 * happen on bdev until thaw_bdev() is called.
215 * If a superblock is found on this device, we take the s_umount semaphore
216 * on it to make sure nobody unmounts until the snapshot creation is done.
217 * The reference counter (bd_fsfreeze_count) guarantees that only the last
218 * unfreeze process can unfreeze the frozen filesystem actually when multiple
219 * freeze requests arrive simultaneously. It counts up in freeze_bdev() and
220 * count down in thaw_bdev(). When it becomes 0, thaw_bdev() will unfreeze
223 struct super_block
*freeze_bdev(struct block_device
*bdev
)
225 struct super_block
*sb
;
228 mutex_lock(&bdev
->bd_fsfreeze_mutex
);
229 if (bdev
->bd_fsfreeze_count
> 0) {
230 bdev
->bd_fsfreeze_count
++;
231 sb
= get_super(bdev
);
232 mutex_unlock(&bdev
->bd_fsfreeze_mutex
);
235 bdev
->bd_fsfreeze_count
++;
237 down(&bdev
->bd_mount_sem
);
238 sb
= get_super(bdev
);
239 if (sb
&& !(sb
->s_flags
& MS_RDONLY
)) {
240 sb
->s_frozen
= SB_FREEZE_WRITE
;
245 sb
->s_frozen
= SB_FREEZE_TRANS
;
248 sync_blockdev(sb
->s_bdev
);
250 if (sb
->s_op
->freeze_fs
) {
251 error
= sb
->s_op
->freeze_fs(sb
);
254 "VFS:Filesystem freeze failed\n");
255 sb
->s_frozen
= SB_UNFROZEN
;
257 up(&bdev
->bd_mount_sem
);
258 bdev
->bd_fsfreeze_count
--;
259 mutex_unlock(&bdev
->bd_fsfreeze_mutex
);
260 return ERR_PTR(error
);
266 mutex_unlock(&bdev
->bd_fsfreeze_mutex
);
268 return sb
; /* thaw_bdev releases s->s_umount and bd_mount_sem */
270 EXPORT_SYMBOL(freeze_bdev
);
273 * thaw_bdev -- unlock filesystem
274 * @bdev: blockdevice to unlock
275 * @sb: associated superblock
277 * Unlocks the filesystem and marks it writeable again after freeze_bdev().
279 int thaw_bdev(struct block_device
*bdev
, struct super_block
*sb
)
283 mutex_lock(&bdev
->bd_fsfreeze_mutex
);
284 if (!bdev
->bd_fsfreeze_count
) {
285 mutex_unlock(&bdev
->bd_fsfreeze_mutex
);
289 bdev
->bd_fsfreeze_count
--;
290 if (bdev
->bd_fsfreeze_count
> 0) {
293 mutex_unlock(&bdev
->bd_fsfreeze_mutex
);
298 BUG_ON(sb
->s_bdev
!= bdev
);
299 if (!(sb
->s_flags
& MS_RDONLY
)) {
300 if (sb
->s_op
->unfreeze_fs
) {
301 error
= sb
->s_op
->unfreeze_fs(sb
);
304 "VFS:Filesystem thaw failed\n");
305 sb
->s_frozen
= SB_FREEZE_TRANS
;
306 bdev
->bd_fsfreeze_count
++;
307 mutex_unlock(&bdev
->bd_fsfreeze_mutex
);
311 sb
->s_frozen
= SB_UNFROZEN
;
313 wake_up(&sb
->s_wait_unfrozen
);
318 up(&bdev
->bd_mount_sem
);
319 mutex_unlock(&bdev
->bd_fsfreeze_mutex
);
322 EXPORT_SYMBOL(thaw_bdev
);
324 static int blkdev_writepage(struct page
*page
, struct writeback_control
*wbc
)
326 return block_write_full_page(page
, blkdev_get_block
, wbc
);
329 static int blkdev_readpage(struct file
* file
, struct page
* page
)
331 return block_read_full_page(page
, blkdev_get_block
);
334 static int blkdev_readpages(struct file
*file
, struct address_space
*mapping
,
335 struct list_head
*pages
, unsigned nr_pages
)
337 return mpage_readpages(mapping
, pages
, nr_pages
, blkdev_get_block
);
340 static int blkdev_write_begin(struct file
*file
, struct address_space
*mapping
,
341 loff_t pos
, unsigned len
, unsigned flags
,
342 struct page
**pagep
, void **fsdata
)
345 return block_write_begin(file
, mapping
, pos
, len
, flags
, pagep
, fsdata
,
349 static int blkdev_write_end(struct file
*file
, struct address_space
*mapping
,
350 loff_t pos
, unsigned len
, unsigned copied
,
351 struct page
*page
, void *fsdata
)
354 ret
= block_write_end(file
, mapping
, pos
, len
, copied
, page
, fsdata
);
357 page_cache_release(page
);
364 * for a block special file file->f_path.dentry->d_inode->i_size is zero
365 * so we compute the size by hand (just as in block_read/write above)
367 static loff_t
block_llseek(struct file
*file
, loff_t offset
, int origin
)
369 struct inode
*bd_inode
= file
->f_mapping
->host
;
373 mutex_lock(&bd_inode
->i_mutex
);
374 size
= i_size_read(bd_inode
);
381 offset
+= file
->f_pos
;
384 if (offset
>= 0 && offset
<= size
) {
385 if (offset
!= file
->f_pos
) {
386 file
->f_pos
= offset
;
390 mutex_unlock(&bd_inode
->i_mutex
);
395 * Filp is never NULL; the only case when ->fsync() is called with
396 * NULL first argument is nfsd_sync_dir() and that's not a directory.
399 static int block_fsync(struct file
*filp
, struct dentry
*dentry
, int datasync
)
401 return sync_blockdev(I_BDEV(filp
->f_mapping
->host
));
408 static __cacheline_aligned_in_smp
DEFINE_SPINLOCK(bdev_lock
);
409 static struct kmem_cache
* bdev_cachep __read_mostly
;
411 static struct inode
*bdev_alloc_inode(struct super_block
*sb
)
413 struct bdev_inode
*ei
= kmem_cache_alloc(bdev_cachep
, GFP_KERNEL
);
416 return &ei
->vfs_inode
;
419 static void bdev_destroy_inode(struct inode
*inode
)
421 struct bdev_inode
*bdi
= BDEV_I(inode
);
423 bdi
->bdev
.bd_inode_backing_dev_info
= NULL
;
424 kmem_cache_free(bdev_cachep
, bdi
);
427 static void init_once(void *foo
)
429 struct bdev_inode
*ei
= (struct bdev_inode
*) foo
;
430 struct block_device
*bdev
= &ei
->bdev
;
432 memset(bdev
, 0, sizeof(*bdev
));
433 mutex_init(&bdev
->bd_mutex
);
434 sema_init(&bdev
->bd_mount_sem
, 1);
435 INIT_LIST_HEAD(&bdev
->bd_inodes
);
436 INIT_LIST_HEAD(&bdev
->bd_list
);
438 INIT_LIST_HEAD(&bdev
->bd_holder_list
);
440 inode_init_once(&ei
->vfs_inode
);
441 /* Initialize mutex for freeze. */
442 mutex_init(&bdev
->bd_fsfreeze_mutex
);
445 static inline void __bd_forget(struct inode
*inode
)
447 list_del_init(&inode
->i_devices
);
448 inode
->i_bdev
= NULL
;
449 inode
->i_mapping
= &inode
->i_data
;
452 static void bdev_clear_inode(struct inode
*inode
)
454 struct block_device
*bdev
= &BDEV_I(inode
)->bdev
;
456 spin_lock(&bdev_lock
);
457 while ( (p
= bdev
->bd_inodes
.next
) != &bdev
->bd_inodes
) {
458 __bd_forget(list_entry(p
, struct inode
, i_devices
));
460 list_del_init(&bdev
->bd_list
);
461 spin_unlock(&bdev_lock
);
464 static const struct super_operations bdev_sops
= {
465 .statfs
= simple_statfs
,
466 .alloc_inode
= bdev_alloc_inode
,
467 .destroy_inode
= bdev_destroy_inode
,
468 .drop_inode
= generic_delete_inode
,
469 .clear_inode
= bdev_clear_inode
,
472 static int bd_get_sb(struct file_system_type
*fs_type
,
473 int flags
, const char *dev_name
, void *data
, struct vfsmount
*mnt
)
475 return get_sb_pseudo(fs_type
, "bdev:", &bdev_sops
, 0x62646576, mnt
);
478 static struct file_system_type bd_type
= {
481 .kill_sb
= kill_anon_super
,
484 struct super_block
*blockdev_superblock __read_mostly
;
486 void __init
bdev_cache_init(void)
489 struct vfsmount
*bd_mnt
;
491 bdev_cachep
= kmem_cache_create("bdev_cache", sizeof(struct bdev_inode
),
492 0, (SLAB_HWCACHE_ALIGN
|SLAB_RECLAIM_ACCOUNT
|
493 SLAB_MEM_SPREAD
|SLAB_PANIC
),
495 err
= register_filesystem(&bd_type
);
497 panic("Cannot register bdev pseudo-fs");
498 bd_mnt
= kern_mount(&bd_type
);
500 panic("Cannot create bdev pseudo-fs");
501 blockdev_superblock
= bd_mnt
->mnt_sb
; /* For writeback */
505 * Most likely _very_ bad one - but then it's hardly critical for small
506 * /dev and can be fixed when somebody will need really large one.
507 * Keep in mind that it will be fed through icache hash function too.
509 static inline unsigned long hash(dev_t dev
)
511 return MAJOR(dev
)+MINOR(dev
);
514 static int bdev_test(struct inode
*inode
, void *data
)
516 return BDEV_I(inode
)->bdev
.bd_dev
== *(dev_t
*)data
;
519 static int bdev_set(struct inode
*inode
, void *data
)
521 BDEV_I(inode
)->bdev
.bd_dev
= *(dev_t
*)data
;
525 static LIST_HEAD(all_bdevs
);
527 struct block_device
*bdget(dev_t dev
)
529 struct block_device
*bdev
;
532 inode
= iget5_locked(blockdev_superblock
, hash(dev
),
533 bdev_test
, bdev_set
, &dev
);
538 bdev
= &BDEV_I(inode
)->bdev
;
540 if (inode
->i_state
& I_NEW
) {
541 bdev
->bd_contains
= NULL
;
542 bdev
->bd_inode
= inode
;
543 bdev
->bd_block_size
= (1 << inode
->i_blkbits
);
544 bdev
->bd_part_count
= 0;
545 bdev
->bd_invalidated
= 0;
546 inode
->i_mode
= S_IFBLK
;
548 inode
->i_bdev
= bdev
;
549 inode
->i_data
.a_ops
= &def_blk_aops
;
550 mapping_set_gfp_mask(&inode
->i_data
, GFP_USER
);
551 inode
->i_data
.backing_dev_info
= &default_backing_dev_info
;
552 spin_lock(&bdev_lock
);
553 list_add(&bdev
->bd_list
, &all_bdevs
);
554 spin_unlock(&bdev_lock
);
555 unlock_new_inode(inode
);
560 EXPORT_SYMBOL(bdget
);
562 long nr_blockdev_pages(void)
564 struct block_device
*bdev
;
566 spin_lock(&bdev_lock
);
567 list_for_each_entry(bdev
, &all_bdevs
, bd_list
) {
568 ret
+= bdev
->bd_inode
->i_mapping
->nrpages
;
570 spin_unlock(&bdev_lock
);
574 void bdput(struct block_device
*bdev
)
576 iput(bdev
->bd_inode
);
579 EXPORT_SYMBOL(bdput
);
581 static struct block_device
*bd_acquire(struct inode
*inode
)
583 struct block_device
*bdev
;
585 spin_lock(&bdev_lock
);
586 bdev
= inode
->i_bdev
;
588 atomic_inc(&bdev
->bd_inode
->i_count
);
589 spin_unlock(&bdev_lock
);
592 spin_unlock(&bdev_lock
);
594 bdev
= bdget(inode
->i_rdev
);
596 spin_lock(&bdev_lock
);
597 if (!inode
->i_bdev
) {
599 * We take an additional bd_inode->i_count for inode,
600 * and it's released in clear_inode() of inode.
601 * So, we can access it via ->i_mapping always
604 atomic_inc(&bdev
->bd_inode
->i_count
);
605 inode
->i_bdev
= bdev
;
606 inode
->i_mapping
= bdev
->bd_inode
->i_mapping
;
607 list_add(&inode
->i_devices
, &bdev
->bd_inodes
);
609 spin_unlock(&bdev_lock
);
614 /* Call when you free inode */
616 void bd_forget(struct inode
*inode
)
618 struct block_device
*bdev
= NULL
;
620 spin_lock(&bdev_lock
);
622 if (!sb_is_blkdev_sb(inode
->i_sb
))
623 bdev
= inode
->i_bdev
;
626 spin_unlock(&bdev_lock
);
629 iput(bdev
->bd_inode
);
632 int bd_claim(struct block_device
*bdev
, void *holder
)
635 spin_lock(&bdev_lock
);
637 /* first decide result */
638 if (bdev
->bd_holder
== holder
)
639 res
= 0; /* already a holder */
640 else if (bdev
->bd_holder
!= NULL
)
641 res
= -EBUSY
; /* held by someone else */
642 else if (bdev
->bd_contains
== bdev
)
643 res
= 0; /* is a whole device which isn't held */
645 else if (bdev
->bd_contains
->bd_holder
== bd_claim
)
646 res
= 0; /* is a partition of a device that is being partitioned */
647 else if (bdev
->bd_contains
->bd_holder
!= NULL
)
648 res
= -EBUSY
; /* is a partition of a held device */
650 res
= 0; /* is a partition of an un-held device */
652 /* now impose change */
654 /* note that for a whole device bd_holders
655 * will be incremented twice, and bd_holder will
656 * be set to bd_claim before being set to holder
658 bdev
->bd_contains
->bd_holders
++;
659 bdev
->bd_contains
->bd_holder
= bd_claim
;
661 bdev
->bd_holder
= holder
;
663 spin_unlock(&bdev_lock
);
667 EXPORT_SYMBOL(bd_claim
);
669 void bd_release(struct block_device
*bdev
)
671 spin_lock(&bdev_lock
);
672 if (!--bdev
->bd_contains
->bd_holders
)
673 bdev
->bd_contains
->bd_holder
= NULL
;
674 if (!--bdev
->bd_holders
)
675 bdev
->bd_holder
= NULL
;
676 spin_unlock(&bdev_lock
);
679 EXPORT_SYMBOL(bd_release
);
683 * Functions for bd_claim_by_kobject / bd_release_from_kobject
685 * If a kobject is passed to bd_claim_by_kobject()
686 * and the kobject has a parent directory,
687 * following symlinks are created:
688 * o from the kobject to the claimed bdev
689 * o from "holders" directory of the bdev to the parent of the kobject
690 * bd_release_from_kobject() removes these symlinks.
693 * If /dev/dm-0 maps to /dev/sda, kobject corresponding to
694 * /sys/block/dm-0/slaves is passed to bd_claim_by_kobject(), then:
695 * /sys/block/dm-0/slaves/sda --> /sys/block/sda
696 * /sys/block/sda/holders/dm-0 --> /sys/block/dm-0
699 static int add_symlink(struct kobject
*from
, struct kobject
*to
)
703 return sysfs_create_link(from
, to
, kobject_name(to
));
706 static void del_symlink(struct kobject
*from
, struct kobject
*to
)
710 sysfs_remove_link(from
, kobject_name(to
));
714 * 'struct bd_holder' contains pointers to kobjects symlinked by
715 * bd_claim_by_kobject.
716 * It's connected to bd_holder_list which is protected by bdev->bd_sem.
719 struct list_head list
; /* chain of holders of the bdev */
720 int count
; /* references from the holder */
721 struct kobject
*sdir
; /* holder object, e.g. "/block/dm-0/slaves" */
722 struct kobject
*hdev
; /* e.g. "/block/dm-0" */
723 struct kobject
*hdir
; /* e.g. "/block/sda/holders" */
724 struct kobject
*sdev
; /* e.g. "/block/sda" */
728 * Get references of related kobjects at once.
729 * Returns 1 on success. 0 on failure.
731 * Should call bd_holder_release_dirs() after successful use.
733 static int bd_holder_grab_dirs(struct block_device
*bdev
,
734 struct bd_holder
*bo
)
739 bo
->sdir
= kobject_get(bo
->sdir
);
743 bo
->hdev
= kobject_get(bo
->sdir
->parent
);
747 bo
->sdev
= kobject_get(&part_to_dev(bdev
->bd_part
)->kobj
);
751 bo
->hdir
= kobject_get(bdev
->bd_part
->holder_dir
);
758 kobject_put(bo
->sdev
);
760 kobject_put(bo
->hdev
);
762 kobject_put(bo
->sdir
);
767 /* Put references of related kobjects at once. */
768 static void bd_holder_release_dirs(struct bd_holder
*bo
)
770 kobject_put(bo
->hdir
);
771 kobject_put(bo
->sdev
);
772 kobject_put(bo
->hdev
);
773 kobject_put(bo
->sdir
);
776 static struct bd_holder
*alloc_bd_holder(struct kobject
*kobj
)
778 struct bd_holder
*bo
;
780 bo
= kzalloc(sizeof(*bo
), GFP_KERNEL
);
790 static void free_bd_holder(struct bd_holder
*bo
)
796 * find_bd_holder - find matching struct bd_holder from the block device
798 * @bdev: struct block device to be searched
799 * @bo: target struct bd_holder
801 * Returns matching entry with @bo in @bdev->bd_holder_list.
802 * If found, increment the reference count and return the pointer.
803 * If not found, returns NULL.
805 static struct bd_holder
*find_bd_holder(struct block_device
*bdev
,
806 struct bd_holder
*bo
)
808 struct bd_holder
*tmp
;
810 list_for_each_entry(tmp
, &bdev
->bd_holder_list
, list
)
811 if (tmp
->sdir
== bo
->sdir
) {
820 * add_bd_holder - create sysfs symlinks for bd_claim() relationship
822 * @bdev: block device to be bd_claimed
823 * @bo: preallocated and initialized by alloc_bd_holder()
825 * Add @bo to @bdev->bd_holder_list, create symlinks.
827 * Returns 0 if symlinks are created.
828 * Returns -ve if something fails.
830 static int add_bd_holder(struct block_device
*bdev
, struct bd_holder
*bo
)
837 if (!bd_holder_grab_dirs(bdev
, bo
))
840 err
= add_symlink(bo
->sdir
, bo
->sdev
);
844 err
= add_symlink(bo
->hdir
, bo
->hdev
);
846 del_symlink(bo
->sdir
, bo
->sdev
);
850 list_add_tail(&bo
->list
, &bdev
->bd_holder_list
);
855 * del_bd_holder - delete sysfs symlinks for bd_claim() relationship
857 * @bdev: block device to be bd_claimed
858 * @kobj: holder's kobject
860 * If there is matching entry with @kobj in @bdev->bd_holder_list
861 * and no other bd_claim() from the same kobject,
862 * remove the struct bd_holder from the list, delete symlinks for it.
864 * Returns a pointer to the struct bd_holder when it's removed from the list
865 * and ready to be freed.
866 * Returns NULL if matching claim isn't found or there is other bd_claim()
867 * by the same kobject.
869 static struct bd_holder
*del_bd_holder(struct block_device
*bdev
,
870 struct kobject
*kobj
)
872 struct bd_holder
*bo
;
874 list_for_each_entry(bo
, &bdev
->bd_holder_list
, list
) {
875 if (bo
->sdir
== kobj
) {
877 BUG_ON(bo
->count
< 0);
880 del_symlink(bo
->sdir
, bo
->sdev
);
881 del_symlink(bo
->hdir
, bo
->hdev
);
882 bd_holder_release_dirs(bo
);
893 * bd_claim_by_kobject - bd_claim() with additional kobject signature
895 * @bdev: block device to be claimed
896 * @holder: holder's signature
897 * @kobj: holder's kobject
899 * Do bd_claim() and if it succeeds, create sysfs symlinks between
900 * the bdev and the holder's kobject.
901 * Use bd_release_from_kobject() when relesing the claimed bdev.
903 * Returns 0 on success. (same as bd_claim())
904 * Returns errno on failure.
906 static int bd_claim_by_kobject(struct block_device
*bdev
, void *holder
,
907 struct kobject
*kobj
)
910 struct bd_holder
*bo
, *found
;
915 bo
= alloc_bd_holder(kobj
);
919 mutex_lock(&bdev
->bd_mutex
);
921 err
= bd_claim(bdev
, holder
);
925 found
= find_bd_holder(bdev
, bo
);
929 err
= add_bd_holder(bdev
, bo
);
935 mutex_unlock(&bdev
->bd_mutex
);
941 * bd_release_from_kobject - bd_release() with additional kobject signature
943 * @bdev: block device to be released
944 * @kobj: holder's kobject
946 * Do bd_release() and remove sysfs symlinks created by bd_claim_by_kobject().
948 static void bd_release_from_kobject(struct block_device
*bdev
,
949 struct kobject
*kobj
)
954 mutex_lock(&bdev
->bd_mutex
);
956 free_bd_holder(del_bd_holder(bdev
, kobj
));
957 mutex_unlock(&bdev
->bd_mutex
);
961 * bd_claim_by_disk - wrapper function for bd_claim_by_kobject()
963 * @bdev: block device to be claimed
964 * @holder: holder's signature
965 * @disk: holder's gendisk
967 * Call bd_claim_by_kobject() with getting @disk->slave_dir.
969 int bd_claim_by_disk(struct block_device
*bdev
, void *holder
,
970 struct gendisk
*disk
)
972 return bd_claim_by_kobject(bdev
, holder
, kobject_get(disk
->slave_dir
));
974 EXPORT_SYMBOL_GPL(bd_claim_by_disk
);
977 * bd_release_from_disk - wrapper function for bd_release_from_kobject()
979 * @bdev: block device to be claimed
980 * @disk: holder's gendisk
982 * Call bd_release_from_kobject() and put @disk->slave_dir.
984 void bd_release_from_disk(struct block_device
*bdev
, struct gendisk
*disk
)
986 bd_release_from_kobject(bdev
, disk
->slave_dir
);
987 kobject_put(disk
->slave_dir
);
989 EXPORT_SYMBOL_GPL(bd_release_from_disk
);
993 * Tries to open block device by device number. Use it ONLY if you
994 * really do not have anything better - i.e. when you are behind a
995 * truly sucky interface and all you are given is a device number. _Never_
996 * to be used for internal purposes. If you ever need it - reconsider
999 struct block_device
*open_by_devnum(dev_t dev
, fmode_t mode
)
1001 struct block_device
*bdev
= bdget(dev
);
1004 err
= blkdev_get(bdev
, mode
);
1005 return err
? ERR_PTR(err
) : bdev
;
1008 EXPORT_SYMBOL(open_by_devnum
);
1011 * flush_disk - invalidates all buffer-cache entries on a disk
1013 * @bdev: struct block device to be flushed
1015 * Invalidates all buffer-cache entries on a disk. It should be called
1016 * when a disk has been changed -- either by a media change or online
1019 static void flush_disk(struct block_device
*bdev
)
1021 if (__invalidate_device(bdev
)) {
1022 char name
[BDEVNAME_SIZE
] = "";
1025 disk_name(bdev
->bd_disk
, 0, name
);
1026 printk(KERN_WARNING
"VFS: busy inodes on changed media or "
1027 "resized disk %s\n", name
);
1032 if (disk_partitionable(bdev
->bd_disk
))
1033 bdev
->bd_invalidated
= 1;
1037 * check_disk_size_change - checks for disk size change and adjusts bdev size.
1038 * @disk: struct gendisk to check
1039 * @bdev: struct bdev to adjust.
1041 * This routine checks to see if the bdev size does not match the disk size
1042 * and adjusts it if it differs.
1044 void check_disk_size_change(struct gendisk
*disk
, struct block_device
*bdev
)
1046 loff_t disk_size
, bdev_size
;
1048 disk_size
= (loff_t
)get_capacity(disk
) << 9;
1049 bdev_size
= i_size_read(bdev
->bd_inode
);
1050 if (disk_size
!= bdev_size
) {
1051 char name
[BDEVNAME_SIZE
];
1053 disk_name(disk
, 0, name
);
1055 "%s: detected capacity change from %lld to %lld\n",
1056 name
, bdev_size
, disk_size
);
1057 i_size_write(bdev
->bd_inode
, disk_size
);
1061 EXPORT_SYMBOL(check_disk_size_change
);
1064 * revalidate_disk - wrapper for lower-level driver's revalidate_disk call-back
1065 * @disk: struct gendisk to be revalidated
1067 * This routine is a wrapper for lower-level driver's revalidate_disk
1068 * call-backs. It is used to do common pre and post operations needed
1069 * for all revalidate_disk operations.
1071 int revalidate_disk(struct gendisk
*disk
)
1073 struct block_device
*bdev
;
1076 if (disk
->fops
->revalidate_disk
)
1077 ret
= disk
->fops
->revalidate_disk(disk
);
1079 bdev
= bdget_disk(disk
, 0);
1083 mutex_lock(&bdev
->bd_mutex
);
1084 check_disk_size_change(disk
, bdev
);
1085 mutex_unlock(&bdev
->bd_mutex
);
1089 EXPORT_SYMBOL(revalidate_disk
);
1092 * This routine checks whether a removable media has been changed,
1093 * and invalidates all buffer-cache-entries in that case. This
1094 * is a relatively slow routine, so we have to try to minimize using
1095 * it. Thus it is called only upon a 'mount' or 'open'. This
1096 * is the best way of combining speed and utility, I think.
1097 * People changing diskettes in the middle of an operation deserve
1100 int check_disk_change(struct block_device
*bdev
)
1102 struct gendisk
*disk
= bdev
->bd_disk
;
1103 struct block_device_operations
* bdops
= disk
->fops
;
1105 if (!bdops
->media_changed
)
1107 if (!bdops
->media_changed(bdev
->bd_disk
))
1111 if (bdops
->revalidate_disk
)
1112 bdops
->revalidate_disk(bdev
->bd_disk
);
1116 EXPORT_SYMBOL(check_disk_change
);
1118 void bd_set_size(struct block_device
*bdev
, loff_t size
)
1120 unsigned bsize
= bdev_logical_block_size(bdev
);
1122 bdev
->bd_inode
->i_size
= size
;
1123 while (bsize
< PAGE_CACHE_SIZE
) {
1128 bdev
->bd_block_size
= bsize
;
1129 bdev
->bd_inode
->i_blkbits
= blksize_bits(bsize
);
1131 EXPORT_SYMBOL(bd_set_size
);
1133 static int __blkdev_put(struct block_device
*bdev
, fmode_t mode
, int for_part
);
1138 * mutex_lock(part->bd_mutex)
1139 * mutex_lock_nested(whole->bd_mutex, 1)
1142 static int __blkdev_get(struct block_device
*bdev
, fmode_t mode
, int for_part
)
1144 struct gendisk
*disk
;
1149 if (mode
& FMODE_READ
)
1151 if (mode
& FMODE_WRITE
)
1154 * hooks: /n/, see "layering violations".
1156 ret
= devcgroup_inode_permission(bdev
->bd_inode
, perm
);
1166 disk
= get_gendisk(bdev
->bd_dev
, &partno
);
1168 goto out_unlock_kernel
;
1170 mutex_lock_nested(&bdev
->bd_mutex
, for_part
);
1171 if (!bdev
->bd_openers
) {
1172 bdev
->bd_disk
= disk
;
1173 bdev
->bd_contains
= bdev
;
1175 struct backing_dev_info
*bdi
;
1178 bdev
->bd_part
= disk_get_part(disk
, partno
);
1182 if (disk
->fops
->open
) {
1183 ret
= disk
->fops
->open(bdev
, mode
);
1184 if (ret
== -ERESTARTSYS
) {
1185 /* Lost a race with 'disk' being
1186 * deleted, try again.
1189 disk_put_part(bdev
->bd_part
);
1190 bdev
->bd_part
= NULL
;
1191 module_put(disk
->fops
->owner
);
1193 bdev
->bd_disk
= NULL
;
1194 mutex_unlock(&bdev
->bd_mutex
);
1200 if (!bdev
->bd_openers
) {
1201 bd_set_size(bdev
,(loff_t
)get_capacity(disk
)<<9);
1202 bdi
= blk_get_backing_dev_info(bdev
);
1204 bdi
= &default_backing_dev_info
;
1205 bdev
->bd_inode
->i_data
.backing_dev_info
= bdi
;
1207 if (bdev
->bd_invalidated
)
1208 rescan_partitions(disk
, bdev
);
1210 struct block_device
*whole
;
1211 whole
= bdget_disk(disk
, 0);
1216 ret
= __blkdev_get(whole
, mode
, 1);
1219 bdev
->bd_contains
= whole
;
1220 bdev
->bd_inode
->i_data
.backing_dev_info
=
1221 whole
->bd_inode
->i_data
.backing_dev_info
;
1222 bdev
->bd_part
= disk_get_part(disk
, partno
);
1223 if (!(disk
->flags
& GENHD_FL_UP
) ||
1224 !bdev
->bd_part
|| !bdev
->bd_part
->nr_sects
) {
1228 bd_set_size(bdev
, (loff_t
)bdev
->bd_part
->nr_sects
<< 9);
1232 module_put(disk
->fops
->owner
);
1234 if (bdev
->bd_contains
== bdev
) {
1235 if (bdev
->bd_disk
->fops
->open
) {
1236 ret
= bdev
->bd_disk
->fops
->open(bdev
, mode
);
1238 goto out_unlock_bdev
;
1240 if (bdev
->bd_invalidated
)
1241 rescan_partitions(bdev
->bd_disk
, bdev
);
1246 bdev
->bd_part_count
++;
1247 mutex_unlock(&bdev
->bd_mutex
);
1252 disk_put_part(bdev
->bd_part
);
1253 bdev
->bd_disk
= NULL
;
1254 bdev
->bd_part
= NULL
;
1255 bdev
->bd_inode
->i_data
.backing_dev_info
= &default_backing_dev_info
;
1256 if (bdev
!= bdev
->bd_contains
)
1257 __blkdev_put(bdev
->bd_contains
, mode
, 1);
1258 bdev
->bd_contains
= NULL
;
1260 mutex_unlock(&bdev
->bd_mutex
);
1265 module_put(disk
->fops
->owner
);
1272 int blkdev_get(struct block_device
*bdev
, fmode_t mode
)
1274 return __blkdev_get(bdev
, mode
, 0);
1276 EXPORT_SYMBOL(blkdev_get
);
1278 static int blkdev_open(struct inode
* inode
, struct file
* filp
)
1280 struct block_device
*bdev
;
1284 * Preserve backwards compatibility and allow large file access
1285 * even if userspace doesn't ask for it explicitly. Some mkfs
1286 * binary needs it. We might want to drop this workaround
1287 * during an unstable branch.
1289 filp
->f_flags
|= O_LARGEFILE
;
1291 if (filp
->f_flags
& O_NDELAY
)
1292 filp
->f_mode
|= FMODE_NDELAY
;
1293 if (filp
->f_flags
& O_EXCL
)
1294 filp
->f_mode
|= FMODE_EXCL
;
1295 if ((filp
->f_flags
& O_ACCMODE
) == 3)
1296 filp
->f_mode
|= FMODE_WRITE_IOCTL
;
1298 bdev
= bd_acquire(inode
);
1302 filp
->f_mapping
= bdev
->bd_inode
->i_mapping
;
1304 res
= blkdev_get(bdev
, filp
->f_mode
);
1308 if (filp
->f_mode
& FMODE_EXCL
) {
1309 res
= bd_claim(bdev
, filp
);
1311 goto out_blkdev_put
;
1317 blkdev_put(bdev
, filp
->f_mode
);
1321 static int __blkdev_put(struct block_device
*bdev
, fmode_t mode
, int for_part
)
1324 struct gendisk
*disk
= bdev
->bd_disk
;
1325 struct block_device
*victim
= NULL
;
1327 mutex_lock_nested(&bdev
->bd_mutex
, for_part
);
1330 bdev
->bd_part_count
--;
1332 if (!--bdev
->bd_openers
) {
1333 sync_blockdev(bdev
);
1336 if (bdev
->bd_contains
== bdev
) {
1337 if (disk
->fops
->release
)
1338 ret
= disk
->fops
->release(disk
, mode
);
1340 if (!bdev
->bd_openers
) {
1341 struct module
*owner
= disk
->fops
->owner
;
1345 disk_put_part(bdev
->bd_part
);
1346 bdev
->bd_part
= NULL
;
1347 bdev
->bd_disk
= NULL
;
1348 bdev
->bd_inode
->i_data
.backing_dev_info
= &default_backing_dev_info
;
1349 if (bdev
!= bdev
->bd_contains
)
1350 victim
= bdev
->bd_contains
;
1351 bdev
->bd_contains
= NULL
;
1354 mutex_unlock(&bdev
->bd_mutex
);
1357 __blkdev_put(victim
, mode
, 1);
1361 int blkdev_put(struct block_device
*bdev
, fmode_t mode
)
1363 return __blkdev_put(bdev
, mode
, 0);
1365 EXPORT_SYMBOL(blkdev_put
);
1367 static int blkdev_close(struct inode
* inode
, struct file
* filp
)
1369 struct block_device
*bdev
= I_BDEV(filp
->f_mapping
->host
);
1370 if (bdev
->bd_holder
== filp
)
1372 return blkdev_put(bdev
, filp
->f_mode
);
1375 static long block_ioctl(struct file
*file
, unsigned cmd
, unsigned long arg
)
1377 struct block_device
*bdev
= I_BDEV(file
->f_mapping
->host
);
1378 fmode_t mode
= file
->f_mode
;
1381 * O_NDELAY can be altered using fcntl(.., F_SETFL, ..), so we have
1382 * to updated it before every ioctl.
1384 if (file
->f_flags
& O_NDELAY
)
1385 mode
|= FMODE_NDELAY
;
1387 mode
&= ~FMODE_NDELAY
;
1389 return blkdev_ioctl(bdev
, mode
, cmd
, arg
);
1393 * Try to release a page associated with block device when the system
1394 * is under memory pressure.
1396 static int blkdev_releasepage(struct page
*page
, gfp_t wait
)
1398 struct super_block
*super
= BDEV_I(page
->mapping
->host
)->bdev
.bd_super
;
1400 if (super
&& super
->s_op
->bdev_try_to_free_page
)
1401 return super
->s_op
->bdev_try_to_free_page(super
, page
, wait
);
1403 return try_to_free_buffers(page
);
1406 static const struct address_space_operations def_blk_aops
= {
1407 .readpage
= blkdev_readpage
,
1408 .readpages
= blkdev_readpages
,
1409 .writepage
= blkdev_writepage
,
1410 .sync_page
= block_sync_page
,
1411 .write_begin
= blkdev_write_begin
,
1412 .write_end
= blkdev_write_end
,
1413 .writepages
= generic_writepages
,
1414 .releasepage
= blkdev_releasepage
,
1415 .direct_IO
= blkdev_direct_IO
,
1418 const struct file_operations def_blk_fops
= {
1419 .open
= blkdev_open
,
1420 .release
= blkdev_close
,
1421 .llseek
= block_llseek
,
1422 .read
= do_sync_read
,
1423 .write
= do_sync_write
,
1424 .aio_read
= generic_file_aio_read
,
1425 .aio_write
= generic_file_aio_write_nolock
,
1426 .mmap
= generic_file_mmap
,
1427 .fsync
= block_fsync
,
1428 .unlocked_ioctl
= block_ioctl
,
1429 #ifdef CONFIG_COMPAT
1430 .compat_ioctl
= compat_blkdev_ioctl
,
1432 .splice_read
= generic_file_splice_read
,
1433 .splice_write
= generic_file_splice_write
,
1436 int ioctl_by_bdev(struct block_device
*bdev
, unsigned cmd
, unsigned long arg
)
1439 mm_segment_t old_fs
= get_fs();
1441 res
= blkdev_ioctl(bdev
, 0, cmd
, arg
);
1446 EXPORT_SYMBOL(ioctl_by_bdev
);
1449 * lookup_bdev - lookup a struct block_device by name
1450 * @pathname: special file representing the block device
1452 * Get a reference to the blockdevice at @pathname in the current
1453 * namespace if possible and return it. Return ERR_PTR(error)
1456 struct block_device
*lookup_bdev(const char *pathname
)
1458 struct block_device
*bdev
;
1459 struct inode
*inode
;
1463 if (!pathname
|| !*pathname
)
1464 return ERR_PTR(-EINVAL
);
1466 error
= kern_path(pathname
, LOOKUP_FOLLOW
, &path
);
1468 return ERR_PTR(error
);
1470 inode
= path
.dentry
->d_inode
;
1472 if (!S_ISBLK(inode
->i_mode
))
1475 if (path
.mnt
->mnt_flags
& MNT_NODEV
)
1478 bdev
= bd_acquire(inode
);
1485 bdev
= ERR_PTR(error
);
1488 EXPORT_SYMBOL(lookup_bdev
);
1491 * open_bdev_exclusive - open a block device by name and set it up for use
1493 * @path: special file representing the block device
1494 * @mode: FMODE_... combination to pass be used
1495 * @holder: owner for exclusion
1497 * Open the blockdevice described by the special file at @path, claim it
1500 struct block_device
*open_bdev_exclusive(const char *path
, fmode_t mode
, void *holder
)
1502 struct block_device
*bdev
;
1505 bdev
= lookup_bdev(path
);
1509 error
= blkdev_get(bdev
, mode
);
1511 return ERR_PTR(error
);
1513 if ((mode
& FMODE_WRITE
) && bdev_read_only(bdev
))
1515 error
= bd_claim(bdev
, holder
);
1522 blkdev_put(bdev
, mode
);
1523 return ERR_PTR(error
);
1526 EXPORT_SYMBOL(open_bdev_exclusive
);
1529 * close_bdev_exclusive - close a blockdevice opened by open_bdev_exclusive()
1531 * @bdev: blockdevice to close
1532 * @mode: mode, must match that used to open.
1534 * This is the counterpart to open_bdev_exclusive().
1536 void close_bdev_exclusive(struct block_device
*bdev
, fmode_t mode
)
1539 blkdev_put(bdev
, mode
);
1542 EXPORT_SYMBOL(close_bdev_exclusive
);
1544 int __invalidate_device(struct block_device
*bdev
)
1546 struct super_block
*sb
= get_super(bdev
);
1551 * no need to lock the super, get_super holds the
1552 * read mutex so the filesystem cannot go away
1553 * under us (->put_super runs with the write lock
1556 shrink_dcache_sb(sb
);
1557 res
= invalidate_inodes(sb
);
1560 invalidate_bdev(bdev
);
1563 EXPORT_SYMBOL(__invalidate_device
);