1 // SPDX-License-Identifier: GPL-2.0-only
5 * Copyright (C) 1991, 1992 Linus Torvalds
6 * Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE
9 #include <linux/init.h>
11 #include <linux/fcntl.h>
12 #include <linux/slab.h>
13 #include <linux/kmod.h>
14 #include <linux/major.h>
15 #include <linux/device_cgroup.h>
16 #include <linux/highmem.h>
17 #include <linux/blkdev.h>
18 #include <linux/backing-dev.h>
19 #include <linux/module.h>
20 #include <linux/blkpg.h>
21 #include <linux/magic.h>
22 #include <linux/dax.h>
23 #include <linux/buffer_head.h>
24 #include <linux/swap.h>
25 #include <linux/pagevec.h>
26 #include <linux/writeback.h>
27 #include <linux/mpage.h>
28 #include <linux/mount.h>
29 #include <linux/pseudo_fs.h>
30 #include <linux/uio.h>
31 #include <linux/namei.h>
32 #include <linux/log2.h>
33 #include <linux/cleancache.h>
34 #include <linux/task_io_accounting_ops.h>
35 #include <linux/falloc.h>
36 #include <linux/uaccess.h>
40 struct block_device bdev
;
41 struct inode vfs_inode
;
44 static const struct address_space_operations def_blk_aops
;
46 static inline struct bdev_inode
*BDEV_I(struct inode
*inode
)
48 return container_of(inode
, struct bdev_inode
, vfs_inode
);
51 struct block_device
*I_BDEV(struct inode
*inode
)
53 return &BDEV_I(inode
)->bdev
;
55 EXPORT_SYMBOL(I_BDEV
);
57 static void bdev_write_inode(struct block_device
*bdev
)
59 struct inode
*inode
= bdev
->bd_inode
;
62 spin_lock(&inode
->i_lock
);
63 while (inode
->i_state
& I_DIRTY
) {
64 spin_unlock(&inode
->i_lock
);
65 ret
= write_inode_now(inode
, true);
67 char name
[BDEVNAME_SIZE
];
68 pr_warn_ratelimited("VFS: Dirty inode writeback failed "
69 "for block device %s (err=%d).\n",
70 bdevname(bdev
, name
), ret
);
72 spin_lock(&inode
->i_lock
);
74 spin_unlock(&inode
->i_lock
);
77 /* Kill _all_ buffers and pagecache , dirty or not.. */
78 void kill_bdev(struct block_device
*bdev
)
80 struct address_space
*mapping
= bdev
->bd_inode
->i_mapping
;
82 if (mapping
->nrpages
== 0 && mapping
->nrexceptional
== 0)
86 truncate_inode_pages(mapping
, 0);
88 EXPORT_SYMBOL(kill_bdev
);
90 /* Invalidate clean unused buffers and pagecache. */
91 void invalidate_bdev(struct block_device
*bdev
)
93 struct address_space
*mapping
= bdev
->bd_inode
->i_mapping
;
95 if (mapping
->nrpages
) {
97 lru_add_drain_all(); /* make sure all lru add caches are flushed */
98 invalidate_mapping_pages(mapping
, 0, -1);
100 /* 99% of the time, we don't need to flush the cleancache on the bdev.
101 * But, for the strange corners, lets be cautious
103 cleancache_invalidate_inode(mapping
);
105 EXPORT_SYMBOL(invalidate_bdev
);
107 static void set_init_blocksize(struct block_device
*bdev
)
109 unsigned bsize
= bdev_logical_block_size(bdev
);
110 loff_t size
= i_size_read(bdev
->bd_inode
);
112 while (bsize
< PAGE_SIZE
) {
117 bdev
->bd_block_size
= bsize
;
118 bdev
->bd_inode
->i_blkbits
= blksize_bits(bsize
);
121 int set_blocksize(struct block_device
*bdev
, int size
)
123 /* Size must be a power of two, and between 512 and PAGE_SIZE */
124 if (size
> PAGE_SIZE
|| size
< 512 || !is_power_of_2(size
))
127 /* Size cannot be smaller than the size supported by the device */
128 if (size
< bdev_logical_block_size(bdev
))
131 /* Don't change the size if it is same as current */
132 if (bdev
->bd_block_size
!= size
) {
134 bdev
->bd_block_size
= size
;
135 bdev
->bd_inode
->i_blkbits
= blksize_bits(size
);
141 EXPORT_SYMBOL(set_blocksize
);
143 int sb_set_blocksize(struct super_block
*sb
, int size
)
145 if (set_blocksize(sb
->s_bdev
, size
))
147 /* If we get here, we know size is power of two
148 * and it's value is between 512 and PAGE_SIZE */
149 sb
->s_blocksize
= size
;
150 sb
->s_blocksize_bits
= blksize_bits(size
);
151 return sb
->s_blocksize
;
154 EXPORT_SYMBOL(sb_set_blocksize
);
156 int sb_min_blocksize(struct super_block
*sb
, int size
)
158 int minsize
= bdev_logical_block_size(sb
->s_bdev
);
161 return sb_set_blocksize(sb
, size
);
164 EXPORT_SYMBOL(sb_min_blocksize
);
167 blkdev_get_block(struct inode
*inode
, sector_t iblock
,
168 struct buffer_head
*bh
, int create
)
170 bh
->b_bdev
= I_BDEV(inode
);
171 bh
->b_blocknr
= iblock
;
172 set_buffer_mapped(bh
);
176 static struct inode
*bdev_file_inode(struct file
*file
)
178 return file
->f_mapping
->host
;
181 static unsigned int dio_bio_write_op(struct kiocb
*iocb
)
183 unsigned int op
= REQ_OP_WRITE
| REQ_SYNC
| REQ_IDLE
;
185 /* avoid the need for a I/O completion work item */
186 if (iocb
->ki_flags
& IOCB_DSYNC
)
191 #define DIO_INLINE_BIO_VECS 4
193 static void blkdev_bio_end_io_simple(struct bio
*bio
)
195 struct task_struct
*waiter
= bio
->bi_private
;
197 WRITE_ONCE(bio
->bi_private
, NULL
);
198 blk_wake_io_task(waiter
);
202 __blkdev_direct_IO_simple(struct kiocb
*iocb
, struct iov_iter
*iter
,
205 struct file
*file
= iocb
->ki_filp
;
206 struct block_device
*bdev
= I_BDEV(bdev_file_inode(file
));
207 struct bio_vec inline_vecs
[DIO_INLINE_BIO_VECS
], *vecs
;
208 loff_t pos
= iocb
->ki_pos
;
209 bool should_dirty
= false;
214 if ((pos
| iov_iter_alignment(iter
)) &
215 (bdev_logical_block_size(bdev
) - 1))
218 if (nr_pages
<= DIO_INLINE_BIO_VECS
)
221 vecs
= kmalloc_array(nr_pages
, sizeof(struct bio_vec
),
227 bio_init(&bio
, vecs
, nr_pages
);
228 bio_set_dev(&bio
, bdev
);
229 bio
.bi_iter
.bi_sector
= pos
>> 9;
230 bio
.bi_write_hint
= iocb
->ki_hint
;
231 bio
.bi_private
= current
;
232 bio
.bi_end_io
= blkdev_bio_end_io_simple
;
233 bio
.bi_ioprio
= iocb
->ki_ioprio
;
235 ret
= bio_iov_iter_get_pages(&bio
, iter
);
238 ret
= bio
.bi_iter
.bi_size
;
240 if (iov_iter_rw(iter
) == READ
) {
241 bio
.bi_opf
= REQ_OP_READ
;
242 if (iter_is_iovec(iter
))
245 bio
.bi_opf
= dio_bio_write_op(iocb
);
246 task_io_account_write(ret
);
248 if (iocb
->ki_flags
& IOCB_HIPRI
)
249 bio_set_polled(&bio
, iocb
);
251 qc
= submit_bio(&bio
);
253 set_current_state(TASK_UNINTERRUPTIBLE
);
254 if (!READ_ONCE(bio
.bi_private
))
256 if (!(iocb
->ki_flags
& IOCB_HIPRI
) ||
257 !blk_poll(bdev_get_queue(bdev
), qc
, true))
260 __set_current_state(TASK_RUNNING
);
262 bio_release_pages(&bio
, should_dirty
);
263 if (unlikely(bio
.bi_status
))
264 ret
= blk_status_to_errno(bio
.bi_status
);
267 if (vecs
!= inline_vecs
)
278 struct task_struct
*waiter
;
283 bool should_dirty
: 1;
288 static struct bio_set blkdev_dio_pool
;
290 static int blkdev_iopoll(struct kiocb
*kiocb
, bool wait
)
292 struct block_device
*bdev
= I_BDEV(kiocb
->ki_filp
->f_mapping
->host
);
293 struct request_queue
*q
= bdev_get_queue(bdev
);
295 return blk_poll(q
, READ_ONCE(kiocb
->ki_cookie
), wait
);
298 static void blkdev_bio_end_io(struct bio
*bio
)
300 struct blkdev_dio
*dio
= bio
->bi_private
;
301 bool should_dirty
= dio
->should_dirty
;
303 if (bio
->bi_status
&& !dio
->bio
.bi_status
)
304 dio
->bio
.bi_status
= bio
->bi_status
;
306 if (!dio
->multi_bio
|| atomic_dec_and_test(&dio
->ref
)) {
308 struct kiocb
*iocb
= dio
->iocb
;
311 if (likely(!dio
->bio
.bi_status
)) {
315 ret
= blk_status_to_errno(dio
->bio
.bi_status
);
318 dio
->iocb
->ki_complete(iocb
, ret
, 0);
322 struct task_struct
*waiter
= dio
->waiter
;
324 WRITE_ONCE(dio
->waiter
, NULL
);
325 blk_wake_io_task(waiter
);
330 bio_check_pages_dirty(bio
);
332 bio_release_pages(bio
, false);
338 __blkdev_direct_IO(struct kiocb
*iocb
, struct iov_iter
*iter
, int nr_pages
)
340 struct file
*file
= iocb
->ki_filp
;
341 struct inode
*inode
= bdev_file_inode(file
);
342 struct block_device
*bdev
= I_BDEV(inode
);
343 struct blk_plug plug
;
344 struct blkdev_dio
*dio
;
346 bool is_poll
= (iocb
->ki_flags
& IOCB_HIPRI
) != 0;
347 bool is_read
= (iov_iter_rw(iter
) == READ
), is_sync
;
348 bool nowait
= (iocb
->ki_flags
& IOCB_NOWAIT
) != 0;
349 loff_t pos
= iocb
->ki_pos
;
350 blk_qc_t qc
= BLK_QC_T_NONE
;
354 if ((pos
| iov_iter_alignment(iter
)) &
355 (bdev_logical_block_size(bdev
) - 1))
363 bio
= bio_alloc_bioset(gfp
, nr_pages
, &blkdev_dio_pool
);
367 dio
= container_of(bio
, struct blkdev_dio
, bio
);
368 dio
->is_sync
= is_sync
= is_sync_kiocb(iocb
);
370 dio
->waiter
= current
;
377 dio
->multi_bio
= false;
378 dio
->should_dirty
= is_read
&& iter_is_iovec(iter
);
381 * Don't plug for HIPRI/polled IO, as those should go straight
385 blk_start_plug(&plug
);
391 bio_set_dev(bio
, bdev
);
392 bio
->bi_iter
.bi_sector
= pos
>> 9;
393 bio
->bi_write_hint
= iocb
->ki_hint
;
394 bio
->bi_private
= dio
;
395 bio
->bi_end_io
= blkdev_bio_end_io
;
396 bio
->bi_ioprio
= iocb
->ki_ioprio
;
398 err
= bio_iov_iter_get_pages(bio
, iter
);
402 bio
->bi_status
= BLK_STS_IOERR
;
408 bio
->bi_opf
= REQ_OP_READ
;
409 if (dio
->should_dirty
)
410 bio_set_pages_dirty(bio
);
412 bio
->bi_opf
= dio_bio_write_op(iocb
);
413 task_io_account_write(bio
->bi_iter
.bi_size
);
417 * Tell underlying layer to not block for resource shortage.
418 * And if we would have blocked, return error inline instead
419 * of through the bio->bi_end_io() callback.
422 bio
->bi_opf
|= (REQ_NOWAIT
| REQ_NOWAIT_INLINE
);
424 dio
->size
+= bio
->bi_iter
.bi_size
;
425 pos
+= bio
->bi_iter
.bi_size
;
427 nr_pages
= iov_iter_npages(iter
, BIO_MAX_PAGES
);
431 if (iocb
->ki_flags
& IOCB_HIPRI
) {
432 bio_set_polled(bio
, iocb
);
436 qc
= submit_bio(bio
);
437 if (qc
== BLK_QC_T_EAGAIN
) {
444 WRITE_ONCE(iocb
->ki_cookie
, qc
);
448 if (!dio
->multi_bio
) {
450 * AIO needs an extra reference to ensure the dio
451 * structure which is embedded into the first bio
456 dio
->multi_bio
= true;
457 atomic_set(&dio
->ref
, 2);
459 atomic_inc(&dio
->ref
);
462 qc
= submit_bio(bio
);
463 if (qc
== BLK_QC_T_EAGAIN
) {
468 ret
+= bio
->bi_iter
.bi_size
;
470 bio
= bio_alloc(gfp
, nr_pages
);
479 blk_finish_plug(&plug
);
485 set_current_state(TASK_UNINTERRUPTIBLE
);
486 if (!READ_ONCE(dio
->waiter
))
489 if (!(iocb
->ki_flags
& IOCB_HIPRI
) ||
490 !blk_poll(bdev_get_queue(bdev
), qc
, true))
493 __set_current_state(TASK_RUNNING
);
497 ret
= blk_status_to_errno(dio
->bio
.bi_status
);
503 blk_finish_plug(&plug
);
508 blkdev_direct_IO(struct kiocb
*iocb
, struct iov_iter
*iter
)
512 nr_pages
= iov_iter_npages(iter
, BIO_MAX_PAGES
+ 1);
515 if (is_sync_kiocb(iocb
) && nr_pages
<= BIO_MAX_PAGES
)
516 return __blkdev_direct_IO_simple(iocb
, iter
, nr_pages
);
518 return __blkdev_direct_IO(iocb
, iter
, min(nr_pages
, BIO_MAX_PAGES
));
521 static __init
int blkdev_init(void)
523 return bioset_init(&blkdev_dio_pool
, 4, offsetof(struct blkdev_dio
, bio
), BIOSET_NEED_BVECS
);
525 module_init(blkdev_init
);
527 int __sync_blockdev(struct block_device
*bdev
, int wait
)
532 return filemap_flush(bdev
->bd_inode
->i_mapping
);
533 return filemap_write_and_wait(bdev
->bd_inode
->i_mapping
);
537 * Write out and wait upon all the dirty data associated with a block
538 * device via its mapping. Does not take the superblock lock.
540 int sync_blockdev(struct block_device
*bdev
)
542 return __sync_blockdev(bdev
, 1);
544 EXPORT_SYMBOL(sync_blockdev
);
547 * Write out and wait upon all dirty data associated with this
548 * device. Filesystem data as well as the underlying block
549 * device. Takes the superblock lock.
551 int fsync_bdev(struct block_device
*bdev
)
553 struct super_block
*sb
= get_super(bdev
);
555 int res
= sync_filesystem(sb
);
559 return sync_blockdev(bdev
);
561 EXPORT_SYMBOL(fsync_bdev
);
564 * freeze_bdev -- lock a filesystem and force it into a consistent state
565 * @bdev: blockdevice to lock
567 * If a superblock is found on this device, we take the s_umount semaphore
568 * on it to make sure nobody unmounts until the snapshot creation is done.
569 * The reference counter (bd_fsfreeze_count) guarantees that only the last
570 * unfreeze process can unfreeze the frozen filesystem actually when multiple
571 * freeze requests arrive simultaneously. It counts up in freeze_bdev() and
572 * count down in thaw_bdev(). When it becomes 0, thaw_bdev() will unfreeze
575 struct super_block
*freeze_bdev(struct block_device
*bdev
)
577 struct super_block
*sb
;
580 mutex_lock(&bdev
->bd_fsfreeze_mutex
);
581 if (++bdev
->bd_fsfreeze_count
> 1) {
583 * We don't even need to grab a reference - the first call
584 * to freeze_bdev grab an active reference and only the last
585 * thaw_bdev drops it.
587 sb
= get_super(bdev
);
590 mutex_unlock(&bdev
->bd_fsfreeze_mutex
);
594 sb
= get_active_super(bdev
);
597 if (sb
->s_op
->freeze_super
)
598 error
= sb
->s_op
->freeze_super(sb
);
600 error
= freeze_super(sb
);
602 deactivate_super(sb
);
603 bdev
->bd_fsfreeze_count
--;
604 mutex_unlock(&bdev
->bd_fsfreeze_mutex
);
605 return ERR_PTR(error
);
607 deactivate_super(sb
);
610 mutex_unlock(&bdev
->bd_fsfreeze_mutex
);
611 return sb
; /* thaw_bdev releases s->s_umount */
613 EXPORT_SYMBOL(freeze_bdev
);
616 * thaw_bdev -- unlock filesystem
617 * @bdev: blockdevice to unlock
618 * @sb: associated superblock
620 * Unlocks the filesystem and marks it writeable again after freeze_bdev().
622 int thaw_bdev(struct block_device
*bdev
, struct super_block
*sb
)
626 mutex_lock(&bdev
->bd_fsfreeze_mutex
);
627 if (!bdev
->bd_fsfreeze_count
)
631 if (--bdev
->bd_fsfreeze_count
> 0)
637 if (sb
->s_op
->thaw_super
)
638 error
= sb
->s_op
->thaw_super(sb
);
640 error
= thaw_super(sb
);
642 bdev
->bd_fsfreeze_count
++;
644 mutex_unlock(&bdev
->bd_fsfreeze_mutex
);
647 EXPORT_SYMBOL(thaw_bdev
);
649 static int blkdev_writepage(struct page
*page
, struct writeback_control
*wbc
)
651 return block_write_full_page(page
, blkdev_get_block
, wbc
);
654 static int blkdev_readpage(struct file
* file
, struct page
* page
)
656 return block_read_full_page(page
, blkdev_get_block
);
659 static int blkdev_readpages(struct file
*file
, struct address_space
*mapping
,
660 struct list_head
*pages
, unsigned nr_pages
)
662 return mpage_readpages(mapping
, pages
, nr_pages
, blkdev_get_block
);
665 static int blkdev_write_begin(struct file
*file
, struct address_space
*mapping
,
666 loff_t pos
, unsigned len
, unsigned flags
,
667 struct page
**pagep
, void **fsdata
)
669 return block_write_begin(mapping
, pos
, len
, flags
, pagep
,
673 static int blkdev_write_end(struct file
*file
, struct address_space
*mapping
,
674 loff_t pos
, unsigned len
, unsigned copied
,
675 struct page
*page
, void *fsdata
)
678 ret
= block_write_end(file
, mapping
, pos
, len
, copied
, page
, fsdata
);
688 * for a block special file file_inode(file)->i_size is zero
689 * so we compute the size by hand (just as in block_read/write above)
691 static loff_t
block_llseek(struct file
*file
, loff_t offset
, int whence
)
693 struct inode
*bd_inode
= bdev_file_inode(file
);
696 inode_lock(bd_inode
);
697 retval
= fixed_size_llseek(file
, offset
, whence
, i_size_read(bd_inode
));
698 inode_unlock(bd_inode
);
702 int blkdev_fsync(struct file
*filp
, loff_t start
, loff_t end
, int datasync
)
704 struct inode
*bd_inode
= bdev_file_inode(filp
);
705 struct block_device
*bdev
= I_BDEV(bd_inode
);
708 error
= file_write_and_wait_range(filp
, start
, end
);
713 * There is no need to serialise calls to blkdev_issue_flush with
714 * i_mutex and doing so causes performance issues with concurrent
715 * O_SYNC writers to a block device.
717 error
= blkdev_issue_flush(bdev
, GFP_KERNEL
, NULL
);
718 if (error
== -EOPNOTSUPP
)
723 EXPORT_SYMBOL(blkdev_fsync
);
726 * bdev_read_page() - Start reading a page from a block device
727 * @bdev: The device to read the page from
728 * @sector: The offset on the device to read the page to (need not be aligned)
729 * @page: The page to read
731 * On entry, the page should be locked. It will be unlocked when the page
732 * has been read. If the block driver implements rw_page synchronously,
733 * that will be true on exit from this function, but it need not be.
735 * Errors returned by this function are usually "soft", eg out of memory, or
736 * queue full; callers should try a different route to read this page rather
737 * than propagate an error back up the stack.
739 * Return: negative errno if an error occurs, 0 if submission was successful.
741 int bdev_read_page(struct block_device
*bdev
, sector_t sector
,
744 const struct block_device_operations
*ops
= bdev
->bd_disk
->fops
;
745 int result
= -EOPNOTSUPP
;
747 if (!ops
->rw_page
|| bdev_get_integrity(bdev
))
750 result
= blk_queue_enter(bdev
->bd_queue
, 0);
753 result
= ops
->rw_page(bdev
, sector
+ get_start_sect(bdev
), page
,
755 blk_queue_exit(bdev
->bd_queue
);
758 EXPORT_SYMBOL_GPL(bdev_read_page
);
761 * bdev_write_page() - Start writing a page to a block device
762 * @bdev: The device to write the page to
763 * @sector: The offset on the device to write the page to (need not be aligned)
764 * @page: The page to write
765 * @wbc: The writeback_control for the write
767 * On entry, the page should be locked and not currently under writeback.
768 * On exit, if the write started successfully, the page will be unlocked and
769 * under writeback. If the write failed already (eg the driver failed to
770 * queue the page to the device), the page will still be locked. If the
771 * caller is a ->writepage implementation, it will need to unlock the page.
773 * Errors returned by this function are usually "soft", eg out of memory, or
774 * queue full; callers should try a different route to write this page rather
775 * than propagate an error back up the stack.
777 * Return: negative errno if an error occurs, 0 if submission was successful.
779 int bdev_write_page(struct block_device
*bdev
, sector_t sector
,
780 struct page
*page
, struct writeback_control
*wbc
)
783 const struct block_device_operations
*ops
= bdev
->bd_disk
->fops
;
785 if (!ops
->rw_page
|| bdev_get_integrity(bdev
))
787 result
= blk_queue_enter(bdev
->bd_queue
, 0);
791 set_page_writeback(page
);
792 result
= ops
->rw_page(bdev
, sector
+ get_start_sect(bdev
), page
,
795 end_page_writeback(page
);
797 clean_page_buffers(page
);
800 blk_queue_exit(bdev
->bd_queue
);
803 EXPORT_SYMBOL_GPL(bdev_write_page
);
809 static __cacheline_aligned_in_smp
DEFINE_SPINLOCK(bdev_lock
);
810 static struct kmem_cache
* bdev_cachep __read_mostly
;
812 static struct inode
*bdev_alloc_inode(struct super_block
*sb
)
814 struct bdev_inode
*ei
= kmem_cache_alloc(bdev_cachep
, GFP_KERNEL
);
817 return &ei
->vfs_inode
;
820 static void bdev_free_inode(struct inode
*inode
)
822 kmem_cache_free(bdev_cachep
, BDEV_I(inode
));
825 static void init_once(void *foo
)
827 struct bdev_inode
*ei
= (struct bdev_inode
*) foo
;
828 struct block_device
*bdev
= &ei
->bdev
;
830 memset(bdev
, 0, sizeof(*bdev
));
831 mutex_init(&bdev
->bd_mutex
);
832 INIT_LIST_HEAD(&bdev
->bd_list
);
834 INIT_LIST_HEAD(&bdev
->bd_holder_disks
);
836 bdev
->bd_bdi
= &noop_backing_dev_info
;
837 inode_init_once(&ei
->vfs_inode
);
838 /* Initialize mutex for freeze. */
839 mutex_init(&bdev
->bd_fsfreeze_mutex
);
842 static void bdev_evict_inode(struct inode
*inode
)
844 struct block_device
*bdev
= &BDEV_I(inode
)->bdev
;
845 truncate_inode_pages_final(&inode
->i_data
);
846 invalidate_inode_buffers(inode
); /* is it needed here? */
848 spin_lock(&bdev_lock
);
849 list_del_init(&bdev
->bd_list
);
850 spin_unlock(&bdev_lock
);
851 /* Detach inode from wb early as bdi_put() may free bdi->wb */
852 inode_detach_wb(inode
);
853 if (bdev
->bd_bdi
!= &noop_backing_dev_info
) {
854 bdi_put(bdev
->bd_bdi
);
855 bdev
->bd_bdi
= &noop_backing_dev_info
;
859 static const struct super_operations bdev_sops
= {
860 .statfs
= simple_statfs
,
861 .alloc_inode
= bdev_alloc_inode
,
862 .free_inode
= bdev_free_inode
,
863 .drop_inode
= generic_delete_inode
,
864 .evict_inode
= bdev_evict_inode
,
867 static int bd_init_fs_context(struct fs_context
*fc
)
869 struct pseudo_fs_context
*ctx
= init_pseudo(fc
, BDEVFS_MAGIC
);
872 fc
->s_iflags
|= SB_I_CGROUPWB
;
873 ctx
->ops
= &bdev_sops
;
877 static struct file_system_type bd_type
= {
879 .init_fs_context
= bd_init_fs_context
,
880 .kill_sb
= kill_anon_super
,
883 struct super_block
*blockdev_superblock __read_mostly
;
884 EXPORT_SYMBOL_GPL(blockdev_superblock
);
886 void __init
bdev_cache_init(void)
889 static struct vfsmount
*bd_mnt
;
891 bdev_cachep
= kmem_cache_create("bdev_cache", sizeof(struct bdev_inode
),
892 0, (SLAB_HWCACHE_ALIGN
|SLAB_RECLAIM_ACCOUNT
|
893 SLAB_MEM_SPREAD
|SLAB_ACCOUNT
|SLAB_PANIC
),
895 err
= register_filesystem(&bd_type
);
897 panic("Cannot register bdev pseudo-fs");
898 bd_mnt
= kern_mount(&bd_type
);
900 panic("Cannot create bdev pseudo-fs");
901 blockdev_superblock
= bd_mnt
->mnt_sb
; /* For writeback */
905 * Most likely _very_ bad one - but then it's hardly critical for small
906 * /dev and can be fixed when somebody will need really large one.
907 * Keep in mind that it will be fed through icache hash function too.
909 static inline unsigned long hash(dev_t dev
)
911 return MAJOR(dev
)+MINOR(dev
);
914 static int bdev_test(struct inode
*inode
, void *data
)
916 return BDEV_I(inode
)->bdev
.bd_dev
== *(dev_t
*)data
;
919 static int bdev_set(struct inode
*inode
, void *data
)
921 BDEV_I(inode
)->bdev
.bd_dev
= *(dev_t
*)data
;
925 static LIST_HEAD(all_bdevs
);
928 * If there is a bdev inode for this device, unhash it so that it gets evicted
929 * as soon as last inode reference is dropped.
931 void bdev_unhash_inode(dev_t dev
)
935 inode
= ilookup5(blockdev_superblock
, hash(dev
), bdev_test
, &dev
);
937 remove_inode_hash(inode
);
942 struct block_device
*bdget(dev_t dev
)
944 struct block_device
*bdev
;
947 inode
= iget5_locked(blockdev_superblock
, hash(dev
),
948 bdev_test
, bdev_set
, &dev
);
953 bdev
= &BDEV_I(inode
)->bdev
;
955 if (inode
->i_state
& I_NEW
) {
956 bdev
->bd_contains
= NULL
;
957 bdev
->bd_super
= NULL
;
958 bdev
->bd_inode
= inode
;
959 bdev
->bd_block_size
= i_blocksize(inode
);
960 bdev
->bd_part_count
= 0;
961 bdev
->bd_invalidated
= 0;
962 inode
->i_mode
= S_IFBLK
;
964 inode
->i_bdev
= bdev
;
965 inode
->i_data
.a_ops
= &def_blk_aops
;
966 mapping_set_gfp_mask(&inode
->i_data
, GFP_USER
);
967 spin_lock(&bdev_lock
);
968 list_add(&bdev
->bd_list
, &all_bdevs
);
969 spin_unlock(&bdev_lock
);
970 unlock_new_inode(inode
);
975 EXPORT_SYMBOL(bdget
);
978 * bdgrab -- Grab a reference to an already referenced block device
979 * @bdev: Block device to grab a reference to.
981 struct block_device
*bdgrab(struct block_device
*bdev
)
983 ihold(bdev
->bd_inode
);
986 EXPORT_SYMBOL(bdgrab
);
988 long nr_blockdev_pages(void)
990 struct block_device
*bdev
;
992 spin_lock(&bdev_lock
);
993 list_for_each_entry(bdev
, &all_bdevs
, bd_list
) {
994 ret
+= bdev
->bd_inode
->i_mapping
->nrpages
;
996 spin_unlock(&bdev_lock
);
1000 void bdput(struct block_device
*bdev
)
1002 iput(bdev
->bd_inode
);
1005 EXPORT_SYMBOL(bdput
);
1007 static struct block_device
*bd_acquire(struct inode
*inode
)
1009 struct block_device
*bdev
;
1011 spin_lock(&bdev_lock
);
1012 bdev
= inode
->i_bdev
;
1013 if (bdev
&& !inode_unhashed(bdev
->bd_inode
)) {
1015 spin_unlock(&bdev_lock
);
1018 spin_unlock(&bdev_lock
);
1021 * i_bdev references block device inode that was already shut down
1022 * (corresponding device got removed). Remove the reference and look
1023 * up block device inode again just in case new device got
1024 * reestablished under the same device number.
1029 bdev
= bdget(inode
->i_rdev
);
1031 spin_lock(&bdev_lock
);
1032 if (!inode
->i_bdev
) {
1034 * We take an additional reference to bd_inode,
1035 * and it's released in clear_inode() of inode.
1036 * So, we can access it via ->i_mapping always
1040 inode
->i_bdev
= bdev
;
1041 inode
->i_mapping
= bdev
->bd_inode
->i_mapping
;
1043 spin_unlock(&bdev_lock
);
1048 /* Call when you free inode */
1050 void bd_forget(struct inode
*inode
)
1052 struct block_device
*bdev
= NULL
;
1054 spin_lock(&bdev_lock
);
1055 if (!sb_is_blkdev_sb(inode
->i_sb
))
1056 bdev
= inode
->i_bdev
;
1057 inode
->i_bdev
= NULL
;
1058 inode
->i_mapping
= &inode
->i_data
;
1059 spin_unlock(&bdev_lock
);
1066 * bd_may_claim - test whether a block device can be claimed
1067 * @bdev: block device of interest
1068 * @whole: whole block device containing @bdev, may equal @bdev
1069 * @holder: holder trying to claim @bdev
1071 * Test whether @bdev can be claimed by @holder.
1074 * spin_lock(&bdev_lock).
1077 * %true if @bdev can be claimed, %false otherwise.
1079 static bool bd_may_claim(struct block_device
*bdev
, struct block_device
*whole
,
1082 if (bdev
->bd_holder
== holder
)
1083 return true; /* already a holder */
1084 else if (bdev
->bd_holder
!= NULL
)
1085 return false; /* held by someone else */
1086 else if (whole
== bdev
)
1087 return true; /* is a whole device which isn't held */
1089 else if (whole
->bd_holder
== bd_may_claim
)
1090 return true; /* is a partition of a device that is being partitioned */
1091 else if (whole
->bd_holder
!= NULL
)
1092 return false; /* is a partition of a held device */
1094 return true; /* is a partition of an un-held device */
1098 * bd_prepare_to_claim - prepare to claim a block device
1099 * @bdev: block device of interest
1100 * @whole: the whole device containing @bdev, may equal @bdev
1101 * @holder: holder trying to claim @bdev
1103 * Prepare to claim @bdev. This function fails if @bdev is already
1104 * claimed by another holder and waits if another claiming is in
1105 * progress. This function doesn't actually claim. On successful
1106 * return, the caller has ownership of bd_claiming and bd_holder[s].
1109 * spin_lock(&bdev_lock). Might release bdev_lock, sleep and regrab
1110 * it multiple times.
1113 * 0 if @bdev can be claimed, -EBUSY otherwise.
1115 static int bd_prepare_to_claim(struct block_device
*bdev
,
1116 struct block_device
*whole
, void *holder
)
1119 /* if someone else claimed, fail */
1120 if (!bd_may_claim(bdev
, whole
, holder
))
1123 /* if claiming is already in progress, wait for it to finish */
1124 if (whole
->bd_claiming
) {
1125 wait_queue_head_t
*wq
= bit_waitqueue(&whole
->bd_claiming
, 0);
1128 prepare_to_wait(wq
, &wait
, TASK_UNINTERRUPTIBLE
);
1129 spin_unlock(&bdev_lock
);
1131 finish_wait(wq
, &wait
);
1132 spin_lock(&bdev_lock
);
1140 static struct gendisk
*bdev_get_gendisk(struct block_device
*bdev
, int *partno
)
1142 struct gendisk
*disk
= get_gendisk(bdev
->bd_dev
, partno
);
1147 * Now that we hold gendisk reference we make sure bdev we looked up is
1148 * not stale. If it is, it means device got removed and created before
1149 * we looked up gendisk and we fail open in such case. Associating
1150 * unhashed bdev with newly created gendisk could lead to two bdevs
1151 * (and thus two independent caches) being associated with one device
1154 if (inode_unhashed(bdev
->bd_inode
)) {
1155 put_disk_and_module(disk
);
1162 * bd_start_claiming - start claiming a block device
1163 * @bdev: block device of interest
1164 * @holder: holder trying to claim @bdev
1166 * @bdev is about to be opened exclusively. Check @bdev can be opened
1167 * exclusively and mark that an exclusive open is in progress. Each
1168 * successful call to this function must be matched with a call to
1169 * either bd_finish_claiming() or bd_abort_claiming() (which do not
1172 * This function is used to gain exclusive access to the block device
1173 * without actually causing other exclusive open attempts to fail. It
1174 * should be used when the open sequence itself requires exclusive
1175 * access but may subsequently fail.
1181 * Pointer to the block device containing @bdev on success, ERR_PTR()
1184 static struct block_device
*bd_start_claiming(struct block_device
*bdev
,
1187 struct gendisk
*disk
;
1188 struct block_device
*whole
;
1194 * @bdev might not have been initialized properly yet, look up
1195 * and grab the outer block device the hard way.
1197 disk
= bdev_get_gendisk(bdev
, &partno
);
1199 return ERR_PTR(-ENXIO
);
1202 * Normally, @bdev should equal what's returned from bdget_disk()
1203 * if partno is 0; however, some drivers (floppy) use multiple
1204 * bdev's for the same physical device and @bdev may be one of the
1205 * aliases. Keep @bdev if partno is 0. This means claimer
1206 * tracking is broken for those devices but it has always been that
1210 whole
= bdget_disk(disk
, 0);
1212 whole
= bdgrab(bdev
);
1214 put_disk_and_module(disk
);
1216 return ERR_PTR(-ENOMEM
);
1218 /* prepare to claim, if successful, mark claiming in progress */
1219 spin_lock(&bdev_lock
);
1221 err
= bd_prepare_to_claim(bdev
, whole
, holder
);
1223 whole
->bd_claiming
= holder
;
1224 spin_unlock(&bdev_lock
);
1227 spin_unlock(&bdev_lock
);
1229 return ERR_PTR(err
);
1234 struct bd_holder_disk
{
1235 struct list_head list
;
1236 struct gendisk
*disk
;
1240 static struct bd_holder_disk
*bd_find_holder_disk(struct block_device
*bdev
,
1241 struct gendisk
*disk
)
1243 struct bd_holder_disk
*holder
;
1245 list_for_each_entry(holder
, &bdev
->bd_holder_disks
, list
)
1246 if (holder
->disk
== disk
)
1251 static int add_symlink(struct kobject
*from
, struct kobject
*to
)
1253 return sysfs_create_link(from
, to
, kobject_name(to
));
1256 static void del_symlink(struct kobject
*from
, struct kobject
*to
)
1258 sysfs_remove_link(from
, kobject_name(to
));
1262 * bd_link_disk_holder - create symlinks between holding disk and slave bdev
1263 * @bdev: the claimed slave bdev
1264 * @disk: the holding disk
1266 * DON'T USE THIS UNLESS YOU'RE ALREADY USING IT.
1268 * This functions creates the following sysfs symlinks.
1270 * - from "slaves" directory of the holder @disk to the claimed @bdev
1271 * - from "holders" directory of the @bdev to the holder @disk
1273 * For example, if /dev/dm-0 maps to /dev/sda and disk for dm-0 is
1274 * passed to bd_link_disk_holder(), then:
1276 * /sys/block/dm-0/slaves/sda --> /sys/block/sda
1277 * /sys/block/sda/holders/dm-0 --> /sys/block/dm-0
1279 * The caller must have claimed @bdev before calling this function and
1280 * ensure that both @bdev and @disk are valid during the creation and
1281 * lifetime of these symlinks.
1287 * 0 on success, -errno on failure.
1289 int bd_link_disk_holder(struct block_device
*bdev
, struct gendisk
*disk
)
1291 struct bd_holder_disk
*holder
;
1294 mutex_lock(&bdev
->bd_mutex
);
1296 WARN_ON_ONCE(!bdev
->bd_holder
);
1298 /* FIXME: remove the following once add_disk() handles errors */
1299 if (WARN_ON(!disk
->slave_dir
|| !bdev
->bd_part
->holder_dir
))
1302 holder
= bd_find_holder_disk(bdev
, disk
);
1308 holder
= kzalloc(sizeof(*holder
), GFP_KERNEL
);
1314 INIT_LIST_HEAD(&holder
->list
);
1315 holder
->disk
= disk
;
1318 ret
= add_symlink(disk
->slave_dir
, &part_to_dev(bdev
->bd_part
)->kobj
);
1322 ret
= add_symlink(bdev
->bd_part
->holder_dir
, &disk_to_dev(disk
)->kobj
);
1326 * bdev could be deleted beneath us which would implicitly destroy
1327 * the holder directory. Hold on to it.
1329 kobject_get(bdev
->bd_part
->holder_dir
);
1331 list_add(&holder
->list
, &bdev
->bd_holder_disks
);
1335 del_symlink(disk
->slave_dir
, &part_to_dev(bdev
->bd_part
)->kobj
);
1339 mutex_unlock(&bdev
->bd_mutex
);
1342 EXPORT_SYMBOL_GPL(bd_link_disk_holder
);
1345 * bd_unlink_disk_holder - destroy symlinks created by bd_link_disk_holder()
1346 * @bdev: the calimed slave bdev
1347 * @disk: the holding disk
1349 * DON'T USE THIS UNLESS YOU'RE ALREADY USING IT.
1354 void bd_unlink_disk_holder(struct block_device
*bdev
, struct gendisk
*disk
)
1356 struct bd_holder_disk
*holder
;
1358 mutex_lock(&bdev
->bd_mutex
);
1360 holder
= bd_find_holder_disk(bdev
, disk
);
1362 if (!WARN_ON_ONCE(holder
== NULL
) && !--holder
->refcnt
) {
1363 del_symlink(disk
->slave_dir
, &part_to_dev(bdev
->bd_part
)->kobj
);
1364 del_symlink(bdev
->bd_part
->holder_dir
,
1365 &disk_to_dev(disk
)->kobj
);
1366 kobject_put(bdev
->bd_part
->holder_dir
);
1367 list_del_init(&holder
->list
);
1371 mutex_unlock(&bdev
->bd_mutex
);
1373 EXPORT_SYMBOL_GPL(bd_unlink_disk_holder
);
1377 * flush_disk - invalidates all buffer-cache entries on a disk
1379 * @bdev: struct block device to be flushed
1380 * @kill_dirty: flag to guide handling of dirty inodes
1382 * Invalidates all buffer-cache entries on a disk. It should be called
1383 * when a disk has been changed -- either by a media change or online
1386 static void flush_disk(struct block_device
*bdev
, bool kill_dirty
)
1388 if (__invalidate_device(bdev
, kill_dirty
)) {
1389 printk(KERN_WARNING
"VFS: busy inodes on changed media or "
1390 "resized disk %s\n",
1391 bdev
->bd_disk
? bdev
->bd_disk
->disk_name
: "");
1396 if (disk_part_scan_enabled(bdev
->bd_disk
))
1397 bdev
->bd_invalidated
= 1;
1401 * check_disk_size_change - checks for disk size change and adjusts bdev size.
1402 * @disk: struct gendisk to check
1403 * @bdev: struct bdev to adjust.
1404 * @verbose: if %true log a message about a size change if there is any
1406 * This routine checks to see if the bdev size does not match the disk size
1407 * and adjusts it if it differs. When shrinking the bdev size, its all caches
1410 void check_disk_size_change(struct gendisk
*disk
, struct block_device
*bdev
,
1413 loff_t disk_size
, bdev_size
;
1415 disk_size
= (loff_t
)get_capacity(disk
) << 9;
1416 bdev_size
= i_size_read(bdev
->bd_inode
);
1417 if (disk_size
!= bdev_size
) {
1420 "%s: detected capacity change from %lld to %lld\n",
1421 disk
->disk_name
, bdev_size
, disk_size
);
1423 i_size_write(bdev
->bd_inode
, disk_size
);
1424 if (bdev_size
> disk_size
)
1425 flush_disk(bdev
, false);
1430 * revalidate_disk - wrapper for lower-level driver's revalidate_disk call-back
1431 * @disk: struct gendisk to be revalidated
1433 * This routine is a wrapper for lower-level driver's revalidate_disk
1434 * call-backs. It is used to do common pre and post operations needed
1435 * for all revalidate_disk operations.
1437 int revalidate_disk(struct gendisk
*disk
)
1441 if (disk
->fops
->revalidate_disk
)
1442 ret
= disk
->fops
->revalidate_disk(disk
);
1445 * Hidden disks don't have associated bdev so there's no point in
1448 if (!(disk
->flags
& GENHD_FL_HIDDEN
)) {
1449 struct block_device
*bdev
= bdget_disk(disk
, 0);
1454 mutex_lock(&bdev
->bd_mutex
);
1455 check_disk_size_change(disk
, bdev
, ret
== 0);
1456 bdev
->bd_invalidated
= 0;
1457 mutex_unlock(&bdev
->bd_mutex
);
1462 EXPORT_SYMBOL(revalidate_disk
);
1465 * This routine checks whether a removable media has been changed,
1466 * and invalidates all buffer-cache-entries in that case. This
1467 * is a relatively slow routine, so we have to try to minimize using
1468 * it. Thus it is called only upon a 'mount' or 'open'. This
1469 * is the best way of combining speed and utility, I think.
1470 * People changing diskettes in the middle of an operation deserve
1473 int check_disk_change(struct block_device
*bdev
)
1475 struct gendisk
*disk
= bdev
->bd_disk
;
1476 const struct block_device_operations
*bdops
= disk
->fops
;
1477 unsigned int events
;
1479 events
= disk_clear_events(disk
, DISK_EVENT_MEDIA_CHANGE
|
1480 DISK_EVENT_EJECT_REQUEST
);
1481 if (!(events
& DISK_EVENT_MEDIA_CHANGE
))
1484 flush_disk(bdev
, true);
1485 if (bdops
->revalidate_disk
)
1486 bdops
->revalidate_disk(bdev
->bd_disk
);
1490 EXPORT_SYMBOL(check_disk_change
);
1492 void bd_set_size(struct block_device
*bdev
, loff_t size
)
1494 inode_lock(bdev
->bd_inode
);
1495 i_size_write(bdev
->bd_inode
, size
);
1496 inode_unlock(bdev
->bd_inode
);
1498 EXPORT_SYMBOL(bd_set_size
);
1500 static void __blkdev_put(struct block_device
*bdev
, fmode_t mode
, int for_part
);
1505 * mutex_lock(part->bd_mutex)
1506 * mutex_lock_nested(whole->bd_mutex, 1)
1509 static int __blkdev_get(struct block_device
*bdev
, fmode_t mode
, int for_part
)
1511 struct gendisk
*disk
;
1515 bool first_open
= false;
1517 if (mode
& FMODE_READ
)
1519 if (mode
& FMODE_WRITE
)
1522 * hooks: /n/, see "layering violations".
1525 ret
= devcgroup_inode_permission(bdev
->bd_inode
, perm
);
1535 disk
= bdev_get_gendisk(bdev
, &partno
);
1539 disk_block_events(disk
);
1540 mutex_lock_nested(&bdev
->bd_mutex
, for_part
);
1541 if (!bdev
->bd_openers
) {
1543 bdev
->bd_disk
= disk
;
1544 bdev
->bd_queue
= disk
->queue
;
1545 bdev
->bd_contains
= bdev
;
1546 bdev
->bd_partno
= partno
;
1550 bdev
->bd_part
= disk_get_part(disk
, partno
);
1555 if (disk
->fops
->open
) {
1556 ret
= disk
->fops
->open(bdev
, mode
);
1557 if (ret
== -ERESTARTSYS
) {
1558 /* Lost a race with 'disk' being
1559 * deleted, try again.
1562 disk_put_part(bdev
->bd_part
);
1563 bdev
->bd_part
= NULL
;
1564 bdev
->bd_disk
= NULL
;
1565 bdev
->bd_queue
= NULL
;
1566 mutex_unlock(&bdev
->bd_mutex
);
1567 disk_unblock_events(disk
);
1568 put_disk_and_module(disk
);
1574 bd_set_size(bdev
,(loff_t
)get_capacity(disk
)<<9);
1575 set_init_blocksize(bdev
);
1579 * If the device is invalidated, rescan partition
1580 * if open succeeded or failed with -ENOMEDIUM.
1581 * The latter is necessary to prevent ghost
1582 * partitions on a removed medium.
1584 if (bdev
->bd_invalidated
) {
1586 rescan_partitions(disk
, bdev
);
1587 else if (ret
== -ENOMEDIUM
)
1588 invalidate_partitions(disk
, bdev
);
1594 struct block_device
*whole
;
1595 whole
= bdget_disk(disk
, 0);
1600 ret
= __blkdev_get(whole
, mode
, 1);
1603 bdev
->bd_contains
= whole
;
1604 bdev
->bd_part
= disk_get_part(disk
, partno
);
1605 if (!(disk
->flags
& GENHD_FL_UP
) ||
1606 !bdev
->bd_part
|| !bdev
->bd_part
->nr_sects
) {
1610 bd_set_size(bdev
, (loff_t
)bdev
->bd_part
->nr_sects
<< 9);
1611 set_init_blocksize(bdev
);
1614 if (bdev
->bd_bdi
== &noop_backing_dev_info
)
1615 bdev
->bd_bdi
= bdi_get(disk
->queue
->backing_dev_info
);
1617 if (bdev
->bd_contains
== bdev
) {
1619 if (bdev
->bd_disk
->fops
->open
)
1620 ret
= bdev
->bd_disk
->fops
->open(bdev
, mode
);
1621 /* the same as first opener case, read comment there */
1622 if (bdev
->bd_invalidated
) {
1624 rescan_partitions(bdev
->bd_disk
, bdev
);
1625 else if (ret
== -ENOMEDIUM
)
1626 invalidate_partitions(bdev
->bd_disk
, bdev
);
1629 goto out_unlock_bdev
;
1634 bdev
->bd_part_count
++;
1635 mutex_unlock(&bdev
->bd_mutex
);
1636 disk_unblock_events(disk
);
1637 /* only one opener holds refs to the module and disk */
1639 put_disk_and_module(disk
);
1643 disk_put_part(bdev
->bd_part
);
1644 bdev
->bd_disk
= NULL
;
1645 bdev
->bd_part
= NULL
;
1646 bdev
->bd_queue
= NULL
;
1647 if (bdev
!= bdev
->bd_contains
)
1648 __blkdev_put(bdev
->bd_contains
, mode
, 1);
1649 bdev
->bd_contains
= NULL
;
1651 mutex_unlock(&bdev
->bd_mutex
);
1652 disk_unblock_events(disk
);
1653 put_disk_and_module(disk
);
1661 * blkdev_get - open a block device
1662 * @bdev: block_device to open
1663 * @mode: FMODE_* mask
1664 * @holder: exclusive holder identifier
1666 * Open @bdev with @mode. If @mode includes %FMODE_EXCL, @bdev is
1667 * open with exclusive access. Specifying %FMODE_EXCL with %NULL
1668 * @holder is invalid. Exclusive opens may nest for the same @holder.
1670 * On success, the reference count of @bdev is unchanged. On failure,
1677 * 0 on success, -errno on failure.
1679 int blkdev_get(struct block_device
*bdev
, fmode_t mode
, void *holder
)
1681 struct block_device
*whole
= NULL
;
1684 WARN_ON_ONCE((mode
& FMODE_EXCL
) && !holder
);
1686 if ((mode
& FMODE_EXCL
) && holder
) {
1687 whole
= bd_start_claiming(bdev
, holder
);
1688 if (IS_ERR(whole
)) {
1690 return PTR_ERR(whole
);
1694 res
= __blkdev_get(bdev
, mode
, 0);
1697 struct gendisk
*disk
= whole
->bd_disk
;
1699 /* finish claiming */
1700 mutex_lock(&bdev
->bd_mutex
);
1701 spin_lock(&bdev_lock
);
1704 BUG_ON(!bd_may_claim(bdev
, whole
, holder
));
1706 * Note that for a whole device bd_holders
1707 * will be incremented twice, and bd_holder
1708 * will be set to bd_may_claim before being
1711 whole
->bd_holders
++;
1712 whole
->bd_holder
= bd_may_claim
;
1714 bdev
->bd_holder
= holder
;
1717 /* tell others that we're done */
1718 BUG_ON(whole
->bd_claiming
!= holder
);
1719 whole
->bd_claiming
= NULL
;
1720 wake_up_bit(&whole
->bd_claiming
, 0);
1722 spin_unlock(&bdev_lock
);
1725 * Block event polling for write claims if requested. Any
1726 * write holder makes the write_holder state stick until
1727 * all are released. This is good enough and tracking
1728 * individual writeable reference is too fragile given the
1729 * way @mode is used in blkdev_get/put().
1731 if (!res
&& (mode
& FMODE_WRITE
) && !bdev
->bd_write_holder
&&
1732 (disk
->flags
& GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE
)) {
1733 bdev
->bd_write_holder
= true;
1734 disk_block_events(disk
);
1737 mutex_unlock(&bdev
->bd_mutex
);
1743 EXPORT_SYMBOL(blkdev_get
);
1746 * blkdev_get_by_path - open a block device by name
1747 * @path: path to the block device to open
1748 * @mode: FMODE_* mask
1749 * @holder: exclusive holder identifier
1751 * Open the blockdevice described by the device file at @path. @mode
1752 * and @holder are identical to blkdev_get().
1754 * On success, the returned block_device has reference count of one.
1760 * Pointer to block_device on success, ERR_PTR(-errno) on failure.
1762 struct block_device
*blkdev_get_by_path(const char *path
, fmode_t mode
,
1765 struct block_device
*bdev
;
1768 bdev
= lookup_bdev(path
);
1772 err
= blkdev_get(bdev
, mode
, holder
);
1774 return ERR_PTR(err
);
1776 if ((mode
& FMODE_WRITE
) && bdev_read_only(bdev
)) {
1777 blkdev_put(bdev
, mode
);
1778 return ERR_PTR(-EACCES
);
1783 EXPORT_SYMBOL(blkdev_get_by_path
);
1786 * blkdev_get_by_dev - open a block device by device number
1787 * @dev: device number of block device to open
1788 * @mode: FMODE_* mask
1789 * @holder: exclusive holder identifier
1791 * Open the blockdevice described by device number @dev. @mode and
1792 * @holder are identical to blkdev_get().
1794 * Use it ONLY if you really do not have anything better - i.e. when
1795 * you are behind a truly sucky interface and all you are given is a
1796 * device number. _Never_ to be used for internal purposes. If you
1797 * ever need it - reconsider your API.
1799 * On success, the returned block_device has reference count of one.
1805 * Pointer to block_device on success, ERR_PTR(-errno) on failure.
1807 struct block_device
*blkdev_get_by_dev(dev_t dev
, fmode_t mode
, void *holder
)
1809 struct block_device
*bdev
;
1814 return ERR_PTR(-ENOMEM
);
1816 err
= blkdev_get(bdev
, mode
, holder
);
1818 return ERR_PTR(err
);
1822 EXPORT_SYMBOL(blkdev_get_by_dev
);
1824 static int blkdev_open(struct inode
* inode
, struct file
* filp
)
1826 struct block_device
*bdev
;
1829 * Preserve backwards compatibility and allow large file access
1830 * even if userspace doesn't ask for it explicitly. Some mkfs
1831 * binary needs it. We might want to drop this workaround
1832 * during an unstable branch.
1834 filp
->f_flags
|= O_LARGEFILE
;
1836 filp
->f_mode
|= FMODE_NOWAIT
;
1838 if (filp
->f_flags
& O_NDELAY
)
1839 filp
->f_mode
|= FMODE_NDELAY
;
1840 if (filp
->f_flags
& O_EXCL
)
1841 filp
->f_mode
|= FMODE_EXCL
;
1842 if ((filp
->f_flags
& O_ACCMODE
) == 3)
1843 filp
->f_mode
|= FMODE_WRITE_IOCTL
;
1845 bdev
= bd_acquire(inode
);
1849 filp
->f_mapping
= bdev
->bd_inode
->i_mapping
;
1850 filp
->f_wb_err
= filemap_sample_wb_err(filp
->f_mapping
);
1852 return blkdev_get(bdev
, filp
->f_mode
, filp
);
1855 static void __blkdev_put(struct block_device
*bdev
, fmode_t mode
, int for_part
)
1857 struct gendisk
*disk
= bdev
->bd_disk
;
1858 struct block_device
*victim
= NULL
;
1860 mutex_lock_nested(&bdev
->bd_mutex
, for_part
);
1862 bdev
->bd_part_count
--;
1864 if (!--bdev
->bd_openers
) {
1865 WARN_ON_ONCE(bdev
->bd_holders
);
1866 sync_blockdev(bdev
);
1869 bdev_write_inode(bdev
);
1871 if (bdev
->bd_contains
== bdev
) {
1872 if (disk
->fops
->release
)
1873 disk
->fops
->release(disk
, mode
);
1875 if (!bdev
->bd_openers
) {
1876 disk_put_part(bdev
->bd_part
);
1877 bdev
->bd_part
= NULL
;
1878 bdev
->bd_disk
= NULL
;
1879 if (bdev
!= bdev
->bd_contains
)
1880 victim
= bdev
->bd_contains
;
1881 bdev
->bd_contains
= NULL
;
1883 put_disk_and_module(disk
);
1885 mutex_unlock(&bdev
->bd_mutex
);
1888 __blkdev_put(victim
, mode
, 1);
1891 void blkdev_put(struct block_device
*bdev
, fmode_t mode
)
1893 mutex_lock(&bdev
->bd_mutex
);
1895 if (mode
& FMODE_EXCL
) {
1899 * Release a claim on the device. The holder fields
1900 * are protected with bdev_lock. bd_mutex is to
1901 * synchronize disk_holder unlinking.
1903 spin_lock(&bdev_lock
);
1905 WARN_ON_ONCE(--bdev
->bd_holders
< 0);
1906 WARN_ON_ONCE(--bdev
->bd_contains
->bd_holders
< 0);
1908 /* bd_contains might point to self, check in a separate step */
1909 if ((bdev_free
= !bdev
->bd_holders
))
1910 bdev
->bd_holder
= NULL
;
1911 if (!bdev
->bd_contains
->bd_holders
)
1912 bdev
->bd_contains
->bd_holder
= NULL
;
1914 spin_unlock(&bdev_lock
);
1917 * If this was the last claim, remove holder link and
1918 * unblock evpoll if it was a write holder.
1920 if (bdev_free
&& bdev
->bd_write_holder
) {
1921 disk_unblock_events(bdev
->bd_disk
);
1922 bdev
->bd_write_holder
= false;
1927 * Trigger event checking and tell drivers to flush MEDIA_CHANGE
1928 * event. This is to ensure detection of media removal commanded
1929 * from userland - e.g. eject(1).
1931 disk_flush_events(bdev
->bd_disk
, DISK_EVENT_MEDIA_CHANGE
);
1933 mutex_unlock(&bdev
->bd_mutex
);
1935 __blkdev_put(bdev
, mode
, 0);
1937 EXPORT_SYMBOL(blkdev_put
);
1939 static int blkdev_close(struct inode
* inode
, struct file
* filp
)
1941 struct block_device
*bdev
= I_BDEV(bdev_file_inode(filp
));
1942 blkdev_put(bdev
, filp
->f_mode
);
1946 static long block_ioctl(struct file
*file
, unsigned cmd
, unsigned long arg
)
1948 struct block_device
*bdev
= I_BDEV(bdev_file_inode(file
));
1949 fmode_t mode
= file
->f_mode
;
1952 * O_NDELAY can be altered using fcntl(.., F_SETFL, ..), so we have
1953 * to updated it before every ioctl.
1955 if (file
->f_flags
& O_NDELAY
)
1956 mode
|= FMODE_NDELAY
;
1958 mode
&= ~FMODE_NDELAY
;
1960 return blkdev_ioctl(bdev
, mode
, cmd
, arg
);
1964 * Write data to the block device. Only intended for the block device itself
1965 * and the raw driver which basically is a fake block device.
1967 * Does not take i_mutex for the write and thus is not for general purpose
1970 ssize_t
blkdev_write_iter(struct kiocb
*iocb
, struct iov_iter
*from
)
1972 struct file
*file
= iocb
->ki_filp
;
1973 struct inode
*bd_inode
= bdev_file_inode(file
);
1974 loff_t size
= i_size_read(bd_inode
);
1975 struct blk_plug plug
;
1978 if (bdev_read_only(I_BDEV(bd_inode
)))
1981 if (!iov_iter_count(from
))
1984 if (iocb
->ki_pos
>= size
)
1987 if ((iocb
->ki_flags
& (IOCB_NOWAIT
| IOCB_DIRECT
)) == IOCB_NOWAIT
)
1990 iov_iter_truncate(from
, size
- iocb
->ki_pos
);
1992 blk_start_plug(&plug
);
1993 ret
= __generic_file_write_iter(iocb
, from
);
1995 ret
= generic_write_sync(iocb
, ret
);
1996 blk_finish_plug(&plug
);
1999 EXPORT_SYMBOL_GPL(blkdev_write_iter
);
2001 ssize_t
blkdev_read_iter(struct kiocb
*iocb
, struct iov_iter
*to
)
2003 struct file
*file
= iocb
->ki_filp
;
2004 struct inode
*bd_inode
= bdev_file_inode(file
);
2005 loff_t size
= i_size_read(bd_inode
);
2006 loff_t pos
= iocb
->ki_pos
;
2012 iov_iter_truncate(to
, size
);
2013 return generic_file_read_iter(iocb
, to
);
2015 EXPORT_SYMBOL_GPL(blkdev_read_iter
);
2018 * Try to release a page associated with block device when the system
2019 * is under memory pressure.
2021 static int blkdev_releasepage(struct page
*page
, gfp_t wait
)
2023 struct super_block
*super
= BDEV_I(page
->mapping
->host
)->bdev
.bd_super
;
2025 if (super
&& super
->s_op
->bdev_try_to_free_page
)
2026 return super
->s_op
->bdev_try_to_free_page(super
, page
, wait
);
2028 return try_to_free_buffers(page
);
2031 static int blkdev_writepages(struct address_space
*mapping
,
2032 struct writeback_control
*wbc
)
2034 return generic_writepages(mapping
, wbc
);
2037 static const struct address_space_operations def_blk_aops
= {
2038 .readpage
= blkdev_readpage
,
2039 .readpages
= blkdev_readpages
,
2040 .writepage
= blkdev_writepage
,
2041 .write_begin
= blkdev_write_begin
,
2042 .write_end
= blkdev_write_end
,
2043 .writepages
= blkdev_writepages
,
2044 .releasepage
= blkdev_releasepage
,
2045 .direct_IO
= blkdev_direct_IO
,
2046 .migratepage
= buffer_migrate_page_norefs
,
2047 .is_dirty_writeback
= buffer_check_dirty_writeback
,
2050 #define BLKDEV_FALLOC_FL_SUPPORTED \
2051 (FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE | \
2052 FALLOC_FL_ZERO_RANGE | FALLOC_FL_NO_HIDE_STALE)
2054 static long blkdev_fallocate(struct file
*file
, int mode
, loff_t start
,
2057 struct block_device
*bdev
= I_BDEV(bdev_file_inode(file
));
2058 struct address_space
*mapping
;
2059 loff_t end
= start
+ len
- 1;
2063 /* Fail if we don't recognize the flags. */
2064 if (mode
& ~BLKDEV_FALLOC_FL_SUPPORTED
)
2067 /* Don't go off the end of the device. */
2068 isize
= i_size_read(bdev
->bd_inode
);
2072 if (mode
& FALLOC_FL_KEEP_SIZE
) {
2073 len
= isize
- start
;
2074 end
= start
+ len
- 1;
2080 * Don't allow IO that isn't aligned to logical block size.
2082 if ((start
| len
) & (bdev_logical_block_size(bdev
) - 1))
2085 /* Invalidate the page cache, including dirty pages. */
2086 mapping
= bdev
->bd_inode
->i_mapping
;
2087 truncate_inode_pages_range(mapping
, start
, end
);
2090 case FALLOC_FL_ZERO_RANGE
:
2091 case FALLOC_FL_ZERO_RANGE
| FALLOC_FL_KEEP_SIZE
:
2092 error
= blkdev_issue_zeroout(bdev
, start
>> 9, len
>> 9,
2093 GFP_KERNEL
, BLKDEV_ZERO_NOUNMAP
);
2095 case FALLOC_FL_PUNCH_HOLE
| FALLOC_FL_KEEP_SIZE
:
2096 error
= blkdev_issue_zeroout(bdev
, start
>> 9, len
>> 9,
2097 GFP_KERNEL
, BLKDEV_ZERO_NOFALLBACK
);
2099 case FALLOC_FL_PUNCH_HOLE
| FALLOC_FL_KEEP_SIZE
| FALLOC_FL_NO_HIDE_STALE
:
2100 error
= blkdev_issue_discard(bdev
, start
>> 9, len
>> 9,
2110 * Invalidate again; if someone wandered in and dirtied a page,
2111 * the caller will be given -EBUSY. The third argument is
2112 * inclusive, so the rounding here is safe.
2114 return invalidate_inode_pages2_range(mapping
,
2115 start
>> PAGE_SHIFT
,
2119 const struct file_operations def_blk_fops
= {
2120 .open
= blkdev_open
,
2121 .release
= blkdev_close
,
2122 .llseek
= block_llseek
,
2123 .read_iter
= blkdev_read_iter
,
2124 .write_iter
= blkdev_write_iter
,
2125 .iopoll
= blkdev_iopoll
,
2126 .mmap
= generic_file_mmap
,
2127 .fsync
= blkdev_fsync
,
2128 .unlocked_ioctl
= block_ioctl
,
2129 #ifdef CONFIG_COMPAT
2130 .compat_ioctl
= compat_blkdev_ioctl
,
2132 .splice_read
= generic_file_splice_read
,
2133 .splice_write
= iter_file_splice_write
,
2134 .fallocate
= blkdev_fallocate
,
2137 int ioctl_by_bdev(struct block_device
*bdev
, unsigned cmd
, unsigned long arg
)
2140 mm_segment_t old_fs
= get_fs();
2142 res
= blkdev_ioctl(bdev
, 0, cmd
, arg
);
2147 EXPORT_SYMBOL(ioctl_by_bdev
);
2150 * lookup_bdev - lookup a struct block_device by name
2151 * @pathname: special file representing the block device
2153 * Get a reference to the blockdevice at @pathname in the current
2154 * namespace if possible and return it. Return ERR_PTR(error)
2157 struct block_device
*lookup_bdev(const char *pathname
)
2159 struct block_device
*bdev
;
2160 struct inode
*inode
;
2164 if (!pathname
|| !*pathname
)
2165 return ERR_PTR(-EINVAL
);
2167 error
= kern_path(pathname
, LOOKUP_FOLLOW
, &path
);
2169 return ERR_PTR(error
);
2171 inode
= d_backing_inode(path
.dentry
);
2173 if (!S_ISBLK(inode
->i_mode
))
2176 if (!may_open_dev(&path
))
2179 bdev
= bd_acquire(inode
);
2186 bdev
= ERR_PTR(error
);
2189 EXPORT_SYMBOL(lookup_bdev
);
2191 int __invalidate_device(struct block_device
*bdev
, bool kill_dirty
)
2193 struct super_block
*sb
= get_super(bdev
);
2198 * no need to lock the super, get_super holds the
2199 * read mutex so the filesystem cannot go away
2200 * under us (->put_super runs with the write lock
2203 shrink_dcache_sb(sb
);
2204 res
= invalidate_inodes(sb
, kill_dirty
);
2207 invalidate_bdev(bdev
);
2210 EXPORT_SYMBOL(__invalidate_device
);
2212 void iterate_bdevs(void (*func
)(struct block_device
*, void *), void *arg
)
2214 struct inode
*inode
, *old_inode
= NULL
;
2216 spin_lock(&blockdev_superblock
->s_inode_list_lock
);
2217 list_for_each_entry(inode
, &blockdev_superblock
->s_inodes
, i_sb_list
) {
2218 struct address_space
*mapping
= inode
->i_mapping
;
2219 struct block_device
*bdev
;
2221 spin_lock(&inode
->i_lock
);
2222 if (inode
->i_state
& (I_FREEING
|I_WILL_FREE
|I_NEW
) ||
2223 mapping
->nrpages
== 0) {
2224 spin_unlock(&inode
->i_lock
);
2228 spin_unlock(&inode
->i_lock
);
2229 spin_unlock(&blockdev_superblock
->s_inode_list_lock
);
2231 * We hold a reference to 'inode' so it couldn't have been
2232 * removed from s_inodes list while we dropped the
2233 * s_inode_list_lock We cannot iput the inode now as we can
2234 * be holding the last reference and we cannot iput it under
2235 * s_inode_list_lock. So we keep the reference and iput it
2240 bdev
= I_BDEV(inode
);
2242 mutex_lock(&bdev
->bd_mutex
);
2243 if (bdev
->bd_openers
)
2245 mutex_unlock(&bdev
->bd_mutex
);
2247 spin_lock(&blockdev_superblock
->s_inode_list_lock
);
2249 spin_unlock(&blockdev_superblock
->s_inode_list_lock
);