4 * Copyright (C) 1991, 1992 Linus Torvalds
5 * Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE
8 #include <linux/init.h>
10 #include <linux/fcntl.h>
11 #include <linux/slab.h>
12 #include <linux/kmod.h>
13 #include <linux/major.h>
14 #include <linux/device_cgroup.h>
15 #include <linux/highmem.h>
16 #include <linux/blkdev.h>
17 #include <linux/backing-dev.h>
18 #include <linux/module.h>
19 #include <linux/blkpg.h>
20 #include <linux/magic.h>
21 #include <linux/dax.h>
22 #include <linux/buffer_head.h>
23 #include <linux/swap.h>
24 #include <linux/pagevec.h>
25 #include <linux/writeback.h>
26 #include <linux/mpage.h>
27 #include <linux/mount.h>
28 #include <linux/uio.h>
29 #include <linux/namei.h>
30 #include <linux/log2.h>
31 #include <linux/cleancache.h>
32 #include <linux/dax.h>
33 #include <linux/badblocks.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 int set_blocksize(struct block_device
*bdev
, int size
)
109 /* Size must be a power of two, and between 512 and PAGE_SIZE */
110 if (size
> PAGE_SIZE
|| size
< 512 || !is_power_of_2(size
))
113 /* Size cannot be smaller than the size supported by the device */
114 if (size
< bdev_logical_block_size(bdev
))
117 /* Don't change the size if it is same as current */
118 if (bdev
->bd_block_size
!= size
) {
120 bdev
->bd_block_size
= size
;
121 bdev
->bd_inode
->i_blkbits
= blksize_bits(size
);
127 EXPORT_SYMBOL(set_blocksize
);
129 int sb_set_blocksize(struct super_block
*sb
, int size
)
131 if (set_blocksize(sb
->s_bdev
, size
))
133 /* If we get here, we know size is power of two
134 * and it's value is between 512 and PAGE_SIZE */
135 sb
->s_blocksize
= size
;
136 sb
->s_blocksize_bits
= blksize_bits(size
);
137 return sb
->s_blocksize
;
140 EXPORT_SYMBOL(sb_set_blocksize
);
142 int sb_min_blocksize(struct super_block
*sb
, int size
)
144 int minsize
= bdev_logical_block_size(sb
->s_bdev
);
147 return sb_set_blocksize(sb
, size
);
150 EXPORT_SYMBOL(sb_min_blocksize
);
153 blkdev_get_block(struct inode
*inode
, sector_t iblock
,
154 struct buffer_head
*bh
, int create
)
156 bh
->b_bdev
= I_BDEV(inode
);
157 bh
->b_blocknr
= iblock
;
158 set_buffer_mapped(bh
);
162 static struct inode
*bdev_file_inode(struct file
*file
)
164 return file
->f_mapping
->host
;
167 static unsigned int dio_bio_write_op(struct kiocb
*iocb
)
169 unsigned int op
= REQ_OP_WRITE
| REQ_SYNC
| REQ_IDLE
;
171 /* avoid the need for a I/O completion work item */
172 if (iocb
->ki_flags
& IOCB_DSYNC
)
177 #define DIO_INLINE_BIO_VECS 4
179 static void blkdev_bio_end_io_simple(struct bio
*bio
)
181 struct task_struct
*waiter
= bio
->bi_private
;
183 WRITE_ONCE(bio
->bi_private
, NULL
);
184 blk_wake_io_task(waiter
);
188 __blkdev_direct_IO_simple(struct kiocb
*iocb
, struct iov_iter
*iter
,
191 struct file
*file
= iocb
->ki_filp
;
192 struct block_device
*bdev
= I_BDEV(bdev_file_inode(file
));
193 struct bio_vec inline_vecs
[DIO_INLINE_BIO_VECS
], *vecs
, *bvec
;
194 loff_t pos
= iocb
->ki_pos
;
195 bool should_dirty
= false;
201 if ((pos
| iov_iter_alignment(iter
)) &
202 (bdev_logical_block_size(bdev
) - 1))
205 if (nr_pages
<= DIO_INLINE_BIO_VECS
)
208 vecs
= kmalloc_array(nr_pages
, sizeof(struct bio_vec
),
214 bio_init(&bio
, vecs
, nr_pages
);
215 bio_set_dev(&bio
, bdev
);
216 bio
.bi_iter
.bi_sector
= pos
>> 9;
217 bio
.bi_write_hint
= iocb
->ki_hint
;
218 bio
.bi_private
= current
;
219 bio
.bi_end_io
= blkdev_bio_end_io_simple
;
220 bio
.bi_ioprio
= iocb
->ki_ioprio
;
222 ret
= bio_iov_iter_get_pages(&bio
, iter
);
225 ret
= bio
.bi_iter
.bi_size
;
227 if (iov_iter_rw(iter
) == READ
) {
228 bio
.bi_opf
= REQ_OP_READ
;
229 if (iter_is_iovec(iter
))
232 bio
.bi_opf
= dio_bio_write_op(iocb
);
233 task_io_account_write(ret
);
235 if (iocb
->ki_flags
& IOCB_HIPRI
)
236 bio
.bi_opf
|= REQ_HIPRI
;
238 qc
= submit_bio(&bio
);
240 set_current_state(TASK_UNINTERRUPTIBLE
);
241 if (!READ_ONCE(bio
.bi_private
))
243 if (!(iocb
->ki_flags
& IOCB_HIPRI
) ||
244 !blk_poll(bdev_get_queue(bdev
), qc
, true))
247 __set_current_state(TASK_RUNNING
);
249 bio_for_each_segment_all(bvec
, &bio
, i
) {
250 if (should_dirty
&& !PageCompound(bvec
->bv_page
))
251 set_page_dirty_lock(bvec
->bv_page
);
252 put_page(bvec
->bv_page
);
255 if (unlikely(bio
.bi_status
))
256 ret
= blk_status_to_errno(bio
.bi_status
);
259 if (vecs
!= inline_vecs
)
270 struct task_struct
*waiter
;
275 bool should_dirty
: 1;
280 static struct bio_set blkdev_dio_pool
;
282 static void blkdev_bio_end_io(struct bio
*bio
)
284 struct blkdev_dio
*dio
= bio
->bi_private
;
285 bool should_dirty
= dio
->should_dirty
;
287 if (dio
->multi_bio
&& !atomic_dec_and_test(&dio
->ref
)) {
288 if (bio
->bi_status
&& !dio
->bio
.bi_status
)
289 dio
->bio
.bi_status
= bio
->bi_status
;
292 struct kiocb
*iocb
= dio
->iocb
;
295 if (likely(!dio
->bio
.bi_status
)) {
299 ret
= blk_status_to_errno(dio
->bio
.bi_status
);
302 dio
->iocb
->ki_complete(iocb
, ret
, 0);
306 struct task_struct
*waiter
= dio
->waiter
;
308 WRITE_ONCE(dio
->waiter
, NULL
);
309 blk_wake_io_task(waiter
);
314 bio_check_pages_dirty(bio
);
316 struct bio_vec
*bvec
;
319 bio_for_each_segment_all(bvec
, bio
, i
)
320 put_page(bvec
->bv_page
);
326 __blkdev_direct_IO(struct kiocb
*iocb
, struct iov_iter
*iter
, int nr_pages
)
328 struct file
*file
= iocb
->ki_filp
;
329 struct inode
*inode
= bdev_file_inode(file
);
330 struct block_device
*bdev
= I_BDEV(inode
);
331 struct blk_plug plug
;
332 struct blkdev_dio
*dio
;
334 bool is_poll
= (iocb
->ki_flags
& IOCB_HIPRI
) != 0;
335 bool is_read
= (iov_iter_rw(iter
) == READ
), is_sync
;
336 loff_t pos
= iocb
->ki_pos
;
337 blk_qc_t qc
= BLK_QC_T_NONE
;
340 if ((pos
| iov_iter_alignment(iter
)) &
341 (bdev_logical_block_size(bdev
) - 1))
344 bio
= bio_alloc_bioset(GFP_KERNEL
, nr_pages
, &blkdev_dio_pool
);
346 dio
= container_of(bio
, struct blkdev_dio
, bio
);
347 dio
->is_sync
= is_sync
= is_sync_kiocb(iocb
);
349 dio
->waiter
= current
;
356 dio
->multi_bio
= false;
357 dio
->should_dirty
= is_read
&& iter_is_iovec(iter
);
360 * Don't plug for HIPRI/polled IO, as those should go straight
364 blk_start_plug(&plug
);
367 bio_set_dev(bio
, bdev
);
368 bio
->bi_iter
.bi_sector
= pos
>> 9;
369 bio
->bi_write_hint
= iocb
->ki_hint
;
370 bio
->bi_private
= dio
;
371 bio
->bi_end_io
= blkdev_bio_end_io
;
372 bio
->bi_ioprio
= iocb
->ki_ioprio
;
374 ret
= bio_iov_iter_get_pages(bio
, iter
);
376 bio
->bi_status
= BLK_STS_IOERR
;
382 bio
->bi_opf
= REQ_OP_READ
;
383 if (dio
->should_dirty
)
384 bio_set_pages_dirty(bio
);
386 bio
->bi_opf
= dio_bio_write_op(iocb
);
387 task_io_account_write(bio
->bi_iter
.bi_size
);
390 dio
->size
+= bio
->bi_iter
.bi_size
;
391 pos
+= bio
->bi_iter
.bi_size
;
393 nr_pages
= iov_iter_npages(iter
, BIO_MAX_PAGES
);
395 if (iocb
->ki_flags
& IOCB_HIPRI
)
396 bio
->bi_opf
|= REQ_HIPRI
;
398 qc
= submit_bio(bio
);
402 if (!dio
->multi_bio
) {
404 * AIO needs an extra reference to ensure the dio
405 * structure which is embedded into the first bio
410 dio
->multi_bio
= true;
411 atomic_set(&dio
->ref
, 2);
413 atomic_inc(&dio
->ref
);
417 bio
= bio_alloc(GFP_KERNEL
, nr_pages
);
421 blk_finish_plug(&plug
);
427 set_current_state(TASK_UNINTERRUPTIBLE
);
428 if (!READ_ONCE(dio
->waiter
))
431 if (!(iocb
->ki_flags
& IOCB_HIPRI
) ||
432 !blk_poll(bdev_get_queue(bdev
), qc
, true))
435 __set_current_state(TASK_RUNNING
);
438 ret
= blk_status_to_errno(dio
->bio
.bi_status
);
447 blkdev_direct_IO(struct kiocb
*iocb
, struct iov_iter
*iter
)
451 nr_pages
= iov_iter_npages(iter
, BIO_MAX_PAGES
+ 1);
454 if (is_sync_kiocb(iocb
) && nr_pages
<= BIO_MAX_PAGES
)
455 return __blkdev_direct_IO_simple(iocb
, iter
, nr_pages
);
457 return __blkdev_direct_IO(iocb
, iter
, min(nr_pages
, BIO_MAX_PAGES
));
460 static __init
int blkdev_init(void)
462 return bioset_init(&blkdev_dio_pool
, 4, offsetof(struct blkdev_dio
, bio
), BIOSET_NEED_BVECS
);
464 module_init(blkdev_init
);
466 int __sync_blockdev(struct block_device
*bdev
, int wait
)
471 return filemap_flush(bdev
->bd_inode
->i_mapping
);
472 return filemap_write_and_wait(bdev
->bd_inode
->i_mapping
);
476 * Write out and wait upon all the dirty data associated with a block
477 * device via its mapping. Does not take the superblock lock.
479 int sync_blockdev(struct block_device
*bdev
)
481 return __sync_blockdev(bdev
, 1);
483 EXPORT_SYMBOL(sync_blockdev
);
486 * Write out and wait upon all dirty data associated with this
487 * device. Filesystem data as well as the underlying block
488 * device. Takes the superblock lock.
490 int fsync_bdev(struct block_device
*bdev
)
492 struct super_block
*sb
= get_super(bdev
);
494 int res
= sync_filesystem(sb
);
498 return sync_blockdev(bdev
);
500 EXPORT_SYMBOL(fsync_bdev
);
503 * freeze_bdev -- lock a filesystem and force it into a consistent state
504 * @bdev: blockdevice to lock
506 * If a superblock is found on this device, we take the s_umount semaphore
507 * on it to make sure nobody unmounts until the snapshot creation is done.
508 * The reference counter (bd_fsfreeze_count) guarantees that only the last
509 * unfreeze process can unfreeze the frozen filesystem actually when multiple
510 * freeze requests arrive simultaneously. It counts up in freeze_bdev() and
511 * count down in thaw_bdev(). When it becomes 0, thaw_bdev() will unfreeze
514 struct super_block
*freeze_bdev(struct block_device
*bdev
)
516 struct super_block
*sb
;
519 mutex_lock(&bdev
->bd_fsfreeze_mutex
);
520 if (++bdev
->bd_fsfreeze_count
> 1) {
522 * We don't even need to grab a reference - the first call
523 * to freeze_bdev grab an active reference and only the last
524 * thaw_bdev drops it.
526 sb
= get_super(bdev
);
529 mutex_unlock(&bdev
->bd_fsfreeze_mutex
);
533 sb
= get_active_super(bdev
);
536 if (sb
->s_op
->freeze_super
)
537 error
= sb
->s_op
->freeze_super(sb
);
539 error
= freeze_super(sb
);
541 deactivate_super(sb
);
542 bdev
->bd_fsfreeze_count
--;
543 mutex_unlock(&bdev
->bd_fsfreeze_mutex
);
544 return ERR_PTR(error
);
546 deactivate_super(sb
);
549 mutex_unlock(&bdev
->bd_fsfreeze_mutex
);
550 return sb
; /* thaw_bdev releases s->s_umount */
552 EXPORT_SYMBOL(freeze_bdev
);
555 * thaw_bdev -- unlock filesystem
556 * @bdev: blockdevice to unlock
557 * @sb: associated superblock
559 * Unlocks the filesystem and marks it writeable again after freeze_bdev().
561 int thaw_bdev(struct block_device
*bdev
, struct super_block
*sb
)
565 mutex_lock(&bdev
->bd_fsfreeze_mutex
);
566 if (!bdev
->bd_fsfreeze_count
)
570 if (--bdev
->bd_fsfreeze_count
> 0)
576 if (sb
->s_op
->thaw_super
)
577 error
= sb
->s_op
->thaw_super(sb
);
579 error
= thaw_super(sb
);
581 bdev
->bd_fsfreeze_count
++;
583 mutex_unlock(&bdev
->bd_fsfreeze_mutex
);
586 EXPORT_SYMBOL(thaw_bdev
);
588 static int blkdev_writepage(struct page
*page
, struct writeback_control
*wbc
)
590 return block_write_full_page(page
, blkdev_get_block
, wbc
);
593 static int blkdev_readpage(struct file
* file
, struct page
* page
)
595 return block_read_full_page(page
, blkdev_get_block
);
598 static int blkdev_readpages(struct file
*file
, struct address_space
*mapping
,
599 struct list_head
*pages
, unsigned nr_pages
)
601 return mpage_readpages(mapping
, pages
, nr_pages
, blkdev_get_block
);
604 static int blkdev_write_begin(struct file
*file
, struct address_space
*mapping
,
605 loff_t pos
, unsigned len
, unsigned flags
,
606 struct page
**pagep
, void **fsdata
)
608 return block_write_begin(mapping
, pos
, len
, flags
, pagep
,
612 static int blkdev_write_end(struct file
*file
, struct address_space
*mapping
,
613 loff_t pos
, unsigned len
, unsigned copied
,
614 struct page
*page
, void *fsdata
)
617 ret
= block_write_end(file
, mapping
, pos
, len
, copied
, page
, fsdata
);
627 * for a block special file file_inode(file)->i_size is zero
628 * so we compute the size by hand (just as in block_read/write above)
630 static loff_t
block_llseek(struct file
*file
, loff_t offset
, int whence
)
632 struct inode
*bd_inode
= bdev_file_inode(file
);
635 inode_lock(bd_inode
);
636 retval
= fixed_size_llseek(file
, offset
, whence
, i_size_read(bd_inode
));
637 inode_unlock(bd_inode
);
641 int blkdev_fsync(struct file
*filp
, loff_t start
, loff_t end
, int datasync
)
643 struct inode
*bd_inode
= bdev_file_inode(filp
);
644 struct block_device
*bdev
= I_BDEV(bd_inode
);
647 error
= file_write_and_wait_range(filp
, start
, end
);
652 * There is no need to serialise calls to blkdev_issue_flush with
653 * i_mutex and doing so causes performance issues with concurrent
654 * O_SYNC writers to a block device.
656 error
= blkdev_issue_flush(bdev
, GFP_KERNEL
, NULL
);
657 if (error
== -EOPNOTSUPP
)
662 EXPORT_SYMBOL(blkdev_fsync
);
665 * bdev_read_page() - Start reading a page from a block device
666 * @bdev: The device to read the page from
667 * @sector: The offset on the device to read the page to (need not be aligned)
668 * @page: The page to read
670 * On entry, the page should be locked. It will be unlocked when the page
671 * has been read. If the block driver implements rw_page synchronously,
672 * that will be true on exit from this function, but it need not be.
674 * Errors returned by this function are usually "soft", eg out of memory, or
675 * queue full; callers should try a different route to read this page rather
676 * than propagate an error back up the stack.
678 * Return: negative errno if an error occurs, 0 if submission was successful.
680 int bdev_read_page(struct block_device
*bdev
, sector_t sector
,
683 const struct block_device_operations
*ops
= bdev
->bd_disk
->fops
;
684 int result
= -EOPNOTSUPP
;
686 if (!ops
->rw_page
|| bdev_get_integrity(bdev
))
689 result
= blk_queue_enter(bdev
->bd_queue
, 0);
692 result
= ops
->rw_page(bdev
, sector
+ get_start_sect(bdev
), page
,
694 blk_queue_exit(bdev
->bd_queue
);
697 EXPORT_SYMBOL_GPL(bdev_read_page
);
700 * bdev_write_page() - Start writing a page to a block device
701 * @bdev: The device to write the page to
702 * @sector: The offset on the device to write the page to (need not be aligned)
703 * @page: The page to write
704 * @wbc: The writeback_control for the write
706 * On entry, the page should be locked and not currently under writeback.
707 * On exit, if the write started successfully, the page will be unlocked and
708 * under writeback. If the write failed already (eg the driver failed to
709 * queue the page to the device), the page will still be locked. If the
710 * caller is a ->writepage implementation, it will need to unlock the page.
712 * Errors returned by this function are usually "soft", eg out of memory, or
713 * queue full; callers should try a different route to write this page rather
714 * than propagate an error back up the stack.
716 * Return: negative errno if an error occurs, 0 if submission was successful.
718 int bdev_write_page(struct block_device
*bdev
, sector_t sector
,
719 struct page
*page
, struct writeback_control
*wbc
)
722 const struct block_device_operations
*ops
= bdev
->bd_disk
->fops
;
724 if (!ops
->rw_page
|| bdev_get_integrity(bdev
))
726 result
= blk_queue_enter(bdev
->bd_queue
, 0);
730 set_page_writeback(page
);
731 result
= ops
->rw_page(bdev
, sector
+ get_start_sect(bdev
), page
,
734 end_page_writeback(page
);
736 clean_page_buffers(page
);
739 blk_queue_exit(bdev
->bd_queue
);
742 EXPORT_SYMBOL_GPL(bdev_write_page
);
748 static __cacheline_aligned_in_smp
DEFINE_SPINLOCK(bdev_lock
);
749 static struct kmem_cache
* bdev_cachep __read_mostly
;
751 static struct inode
*bdev_alloc_inode(struct super_block
*sb
)
753 struct bdev_inode
*ei
= kmem_cache_alloc(bdev_cachep
, GFP_KERNEL
);
756 return &ei
->vfs_inode
;
759 static void bdev_i_callback(struct rcu_head
*head
)
761 struct inode
*inode
= container_of(head
, struct inode
, i_rcu
);
762 struct bdev_inode
*bdi
= BDEV_I(inode
);
764 kmem_cache_free(bdev_cachep
, bdi
);
767 static void bdev_destroy_inode(struct inode
*inode
)
769 call_rcu(&inode
->i_rcu
, bdev_i_callback
);
772 static void init_once(void *foo
)
774 struct bdev_inode
*ei
= (struct bdev_inode
*) foo
;
775 struct block_device
*bdev
= &ei
->bdev
;
777 memset(bdev
, 0, sizeof(*bdev
));
778 mutex_init(&bdev
->bd_mutex
);
779 INIT_LIST_HEAD(&bdev
->bd_list
);
781 INIT_LIST_HEAD(&bdev
->bd_holder_disks
);
783 bdev
->bd_bdi
= &noop_backing_dev_info
;
784 inode_init_once(&ei
->vfs_inode
);
785 /* Initialize mutex for freeze. */
786 mutex_init(&bdev
->bd_fsfreeze_mutex
);
789 static void bdev_evict_inode(struct inode
*inode
)
791 struct block_device
*bdev
= &BDEV_I(inode
)->bdev
;
792 truncate_inode_pages_final(&inode
->i_data
);
793 invalidate_inode_buffers(inode
); /* is it needed here? */
795 spin_lock(&bdev_lock
);
796 list_del_init(&bdev
->bd_list
);
797 spin_unlock(&bdev_lock
);
798 /* Detach inode from wb early as bdi_put() may free bdi->wb */
799 inode_detach_wb(inode
);
800 if (bdev
->bd_bdi
!= &noop_backing_dev_info
) {
801 bdi_put(bdev
->bd_bdi
);
802 bdev
->bd_bdi
= &noop_backing_dev_info
;
806 static const struct super_operations bdev_sops
= {
807 .statfs
= simple_statfs
,
808 .alloc_inode
= bdev_alloc_inode
,
809 .destroy_inode
= bdev_destroy_inode
,
810 .drop_inode
= generic_delete_inode
,
811 .evict_inode
= bdev_evict_inode
,
814 static struct dentry
*bd_mount(struct file_system_type
*fs_type
,
815 int flags
, const char *dev_name
, void *data
)
818 dent
= mount_pseudo(fs_type
, "bdev:", &bdev_sops
, NULL
, BDEVFS_MAGIC
);
820 dent
->d_sb
->s_iflags
|= SB_I_CGROUPWB
;
824 static struct file_system_type bd_type
= {
827 .kill_sb
= kill_anon_super
,
830 struct super_block
*blockdev_superblock __read_mostly
;
831 EXPORT_SYMBOL_GPL(blockdev_superblock
);
833 void __init
bdev_cache_init(void)
836 static struct vfsmount
*bd_mnt
;
838 bdev_cachep
= kmem_cache_create("bdev_cache", sizeof(struct bdev_inode
),
839 0, (SLAB_HWCACHE_ALIGN
|SLAB_RECLAIM_ACCOUNT
|
840 SLAB_MEM_SPREAD
|SLAB_ACCOUNT
|SLAB_PANIC
),
842 err
= register_filesystem(&bd_type
);
844 panic("Cannot register bdev pseudo-fs");
845 bd_mnt
= kern_mount(&bd_type
);
847 panic("Cannot create bdev pseudo-fs");
848 blockdev_superblock
= bd_mnt
->mnt_sb
; /* For writeback */
852 * Most likely _very_ bad one - but then it's hardly critical for small
853 * /dev and can be fixed when somebody will need really large one.
854 * Keep in mind that it will be fed through icache hash function too.
856 static inline unsigned long hash(dev_t dev
)
858 return MAJOR(dev
)+MINOR(dev
);
861 static int bdev_test(struct inode
*inode
, void *data
)
863 return BDEV_I(inode
)->bdev
.bd_dev
== *(dev_t
*)data
;
866 static int bdev_set(struct inode
*inode
, void *data
)
868 BDEV_I(inode
)->bdev
.bd_dev
= *(dev_t
*)data
;
872 static LIST_HEAD(all_bdevs
);
875 * If there is a bdev inode for this device, unhash it so that it gets evicted
876 * as soon as last inode reference is dropped.
878 void bdev_unhash_inode(dev_t dev
)
882 inode
= ilookup5(blockdev_superblock
, hash(dev
), bdev_test
, &dev
);
884 remove_inode_hash(inode
);
889 struct block_device
*bdget(dev_t dev
)
891 struct block_device
*bdev
;
894 inode
= iget5_locked(blockdev_superblock
, hash(dev
),
895 bdev_test
, bdev_set
, &dev
);
900 bdev
= &BDEV_I(inode
)->bdev
;
902 if (inode
->i_state
& I_NEW
) {
903 bdev
->bd_contains
= NULL
;
904 bdev
->bd_super
= NULL
;
905 bdev
->bd_inode
= inode
;
906 bdev
->bd_block_size
= i_blocksize(inode
);
907 bdev
->bd_part_count
= 0;
908 bdev
->bd_invalidated
= 0;
909 inode
->i_mode
= S_IFBLK
;
911 inode
->i_bdev
= bdev
;
912 inode
->i_data
.a_ops
= &def_blk_aops
;
913 mapping_set_gfp_mask(&inode
->i_data
, GFP_USER
);
914 spin_lock(&bdev_lock
);
915 list_add(&bdev
->bd_list
, &all_bdevs
);
916 spin_unlock(&bdev_lock
);
917 unlock_new_inode(inode
);
922 EXPORT_SYMBOL(bdget
);
925 * bdgrab -- Grab a reference to an already referenced block device
926 * @bdev: Block device to grab a reference to.
928 struct block_device
*bdgrab(struct block_device
*bdev
)
930 ihold(bdev
->bd_inode
);
933 EXPORT_SYMBOL(bdgrab
);
935 long nr_blockdev_pages(void)
937 struct block_device
*bdev
;
939 spin_lock(&bdev_lock
);
940 list_for_each_entry(bdev
, &all_bdevs
, bd_list
) {
941 ret
+= bdev
->bd_inode
->i_mapping
->nrpages
;
943 spin_unlock(&bdev_lock
);
947 void bdput(struct block_device
*bdev
)
949 iput(bdev
->bd_inode
);
952 EXPORT_SYMBOL(bdput
);
954 static struct block_device
*bd_acquire(struct inode
*inode
)
956 struct block_device
*bdev
;
958 spin_lock(&bdev_lock
);
959 bdev
= inode
->i_bdev
;
960 if (bdev
&& !inode_unhashed(bdev
->bd_inode
)) {
962 spin_unlock(&bdev_lock
);
965 spin_unlock(&bdev_lock
);
968 * i_bdev references block device inode that was already shut down
969 * (corresponding device got removed). Remove the reference and look
970 * up block device inode again just in case new device got
971 * reestablished under the same device number.
976 bdev
= bdget(inode
->i_rdev
);
978 spin_lock(&bdev_lock
);
979 if (!inode
->i_bdev
) {
981 * We take an additional reference to bd_inode,
982 * and it's released in clear_inode() of inode.
983 * So, we can access it via ->i_mapping always
987 inode
->i_bdev
= bdev
;
988 inode
->i_mapping
= bdev
->bd_inode
->i_mapping
;
990 spin_unlock(&bdev_lock
);
995 /* Call when you free inode */
997 void bd_forget(struct inode
*inode
)
999 struct block_device
*bdev
= NULL
;
1001 spin_lock(&bdev_lock
);
1002 if (!sb_is_blkdev_sb(inode
->i_sb
))
1003 bdev
= inode
->i_bdev
;
1004 inode
->i_bdev
= NULL
;
1005 inode
->i_mapping
= &inode
->i_data
;
1006 spin_unlock(&bdev_lock
);
1013 * bd_may_claim - test whether a block device can be claimed
1014 * @bdev: block device of interest
1015 * @whole: whole block device containing @bdev, may equal @bdev
1016 * @holder: holder trying to claim @bdev
1018 * Test whether @bdev can be claimed by @holder.
1021 * spin_lock(&bdev_lock).
1024 * %true if @bdev can be claimed, %false otherwise.
1026 static bool bd_may_claim(struct block_device
*bdev
, struct block_device
*whole
,
1029 if (bdev
->bd_holder
== holder
)
1030 return true; /* already a holder */
1031 else if (bdev
->bd_holder
!= NULL
)
1032 return false; /* held by someone else */
1033 else if (whole
== bdev
)
1034 return true; /* is a whole device which isn't held */
1036 else if (whole
->bd_holder
== bd_may_claim
)
1037 return true; /* is a partition of a device that is being partitioned */
1038 else if (whole
->bd_holder
!= NULL
)
1039 return false; /* is a partition of a held device */
1041 return true; /* is a partition of an un-held device */
1045 * bd_prepare_to_claim - prepare to claim a block device
1046 * @bdev: block device of interest
1047 * @whole: the whole device containing @bdev, may equal @bdev
1048 * @holder: holder trying to claim @bdev
1050 * Prepare to claim @bdev. This function fails if @bdev is already
1051 * claimed by another holder and waits if another claiming is in
1052 * progress. This function doesn't actually claim. On successful
1053 * return, the caller has ownership of bd_claiming and bd_holder[s].
1056 * spin_lock(&bdev_lock). Might release bdev_lock, sleep and regrab
1057 * it multiple times.
1060 * 0 if @bdev can be claimed, -EBUSY otherwise.
1062 static int bd_prepare_to_claim(struct block_device
*bdev
,
1063 struct block_device
*whole
, void *holder
)
1066 /* if someone else claimed, fail */
1067 if (!bd_may_claim(bdev
, whole
, holder
))
1070 /* if claiming is already in progress, wait for it to finish */
1071 if (whole
->bd_claiming
) {
1072 wait_queue_head_t
*wq
= bit_waitqueue(&whole
->bd_claiming
, 0);
1075 prepare_to_wait(wq
, &wait
, TASK_UNINTERRUPTIBLE
);
1076 spin_unlock(&bdev_lock
);
1078 finish_wait(wq
, &wait
);
1079 spin_lock(&bdev_lock
);
1087 static struct gendisk
*bdev_get_gendisk(struct block_device
*bdev
, int *partno
)
1089 struct gendisk
*disk
= get_gendisk(bdev
->bd_dev
, partno
);
1094 * Now that we hold gendisk reference we make sure bdev we looked up is
1095 * not stale. If it is, it means device got removed and created before
1096 * we looked up gendisk and we fail open in such case. Associating
1097 * unhashed bdev with newly created gendisk could lead to two bdevs
1098 * (and thus two independent caches) being associated with one device
1101 if (inode_unhashed(bdev
->bd_inode
)) {
1102 put_disk_and_module(disk
);
1109 * bd_start_claiming - start claiming a block device
1110 * @bdev: block device of interest
1111 * @holder: holder trying to claim @bdev
1113 * @bdev is about to be opened exclusively. Check @bdev can be opened
1114 * exclusively and mark that an exclusive open is in progress. Each
1115 * successful call to this function must be matched with a call to
1116 * either bd_finish_claiming() or bd_abort_claiming() (which do not
1119 * This function is used to gain exclusive access to the block device
1120 * without actually causing other exclusive open attempts to fail. It
1121 * should be used when the open sequence itself requires exclusive
1122 * access but may subsequently fail.
1128 * Pointer to the block device containing @bdev on success, ERR_PTR()
1131 static struct block_device
*bd_start_claiming(struct block_device
*bdev
,
1134 struct gendisk
*disk
;
1135 struct block_device
*whole
;
1141 * @bdev might not have been initialized properly yet, look up
1142 * and grab the outer block device the hard way.
1144 disk
= bdev_get_gendisk(bdev
, &partno
);
1146 return ERR_PTR(-ENXIO
);
1149 * Normally, @bdev should equal what's returned from bdget_disk()
1150 * if partno is 0; however, some drivers (floppy) use multiple
1151 * bdev's for the same physical device and @bdev may be one of the
1152 * aliases. Keep @bdev if partno is 0. This means claimer
1153 * tracking is broken for those devices but it has always been that
1157 whole
= bdget_disk(disk
, 0);
1159 whole
= bdgrab(bdev
);
1161 put_disk_and_module(disk
);
1163 return ERR_PTR(-ENOMEM
);
1165 /* prepare to claim, if successful, mark claiming in progress */
1166 spin_lock(&bdev_lock
);
1168 err
= bd_prepare_to_claim(bdev
, whole
, holder
);
1170 whole
->bd_claiming
= holder
;
1171 spin_unlock(&bdev_lock
);
1174 spin_unlock(&bdev_lock
);
1176 return ERR_PTR(err
);
1181 struct bd_holder_disk
{
1182 struct list_head list
;
1183 struct gendisk
*disk
;
1187 static struct bd_holder_disk
*bd_find_holder_disk(struct block_device
*bdev
,
1188 struct gendisk
*disk
)
1190 struct bd_holder_disk
*holder
;
1192 list_for_each_entry(holder
, &bdev
->bd_holder_disks
, list
)
1193 if (holder
->disk
== disk
)
1198 static int add_symlink(struct kobject
*from
, struct kobject
*to
)
1200 return sysfs_create_link(from
, to
, kobject_name(to
));
1203 static void del_symlink(struct kobject
*from
, struct kobject
*to
)
1205 sysfs_remove_link(from
, kobject_name(to
));
1209 * bd_link_disk_holder - create symlinks between holding disk and slave bdev
1210 * @bdev: the claimed slave bdev
1211 * @disk: the holding disk
1213 * DON'T USE THIS UNLESS YOU'RE ALREADY USING IT.
1215 * This functions creates the following sysfs symlinks.
1217 * - from "slaves" directory of the holder @disk to the claimed @bdev
1218 * - from "holders" directory of the @bdev to the holder @disk
1220 * For example, if /dev/dm-0 maps to /dev/sda and disk for dm-0 is
1221 * passed to bd_link_disk_holder(), then:
1223 * /sys/block/dm-0/slaves/sda --> /sys/block/sda
1224 * /sys/block/sda/holders/dm-0 --> /sys/block/dm-0
1226 * The caller must have claimed @bdev before calling this function and
1227 * ensure that both @bdev and @disk are valid during the creation and
1228 * lifetime of these symlinks.
1234 * 0 on success, -errno on failure.
1236 int bd_link_disk_holder(struct block_device
*bdev
, struct gendisk
*disk
)
1238 struct bd_holder_disk
*holder
;
1241 mutex_lock(&bdev
->bd_mutex
);
1243 WARN_ON_ONCE(!bdev
->bd_holder
);
1245 /* FIXME: remove the following once add_disk() handles errors */
1246 if (WARN_ON(!disk
->slave_dir
|| !bdev
->bd_part
->holder_dir
))
1249 holder
= bd_find_holder_disk(bdev
, disk
);
1255 holder
= kzalloc(sizeof(*holder
), GFP_KERNEL
);
1261 INIT_LIST_HEAD(&holder
->list
);
1262 holder
->disk
= disk
;
1265 ret
= add_symlink(disk
->slave_dir
, &part_to_dev(bdev
->bd_part
)->kobj
);
1269 ret
= add_symlink(bdev
->bd_part
->holder_dir
, &disk_to_dev(disk
)->kobj
);
1273 * bdev could be deleted beneath us which would implicitly destroy
1274 * the holder directory. Hold on to it.
1276 kobject_get(bdev
->bd_part
->holder_dir
);
1278 list_add(&holder
->list
, &bdev
->bd_holder_disks
);
1282 del_symlink(disk
->slave_dir
, &part_to_dev(bdev
->bd_part
)->kobj
);
1286 mutex_unlock(&bdev
->bd_mutex
);
1289 EXPORT_SYMBOL_GPL(bd_link_disk_holder
);
1292 * bd_unlink_disk_holder - destroy symlinks created by bd_link_disk_holder()
1293 * @bdev: the calimed slave bdev
1294 * @disk: the holding disk
1296 * DON'T USE THIS UNLESS YOU'RE ALREADY USING IT.
1301 void bd_unlink_disk_holder(struct block_device
*bdev
, struct gendisk
*disk
)
1303 struct bd_holder_disk
*holder
;
1305 mutex_lock(&bdev
->bd_mutex
);
1307 holder
= bd_find_holder_disk(bdev
, disk
);
1309 if (!WARN_ON_ONCE(holder
== NULL
) && !--holder
->refcnt
) {
1310 del_symlink(disk
->slave_dir
, &part_to_dev(bdev
->bd_part
)->kobj
);
1311 del_symlink(bdev
->bd_part
->holder_dir
,
1312 &disk_to_dev(disk
)->kobj
);
1313 kobject_put(bdev
->bd_part
->holder_dir
);
1314 list_del_init(&holder
->list
);
1318 mutex_unlock(&bdev
->bd_mutex
);
1320 EXPORT_SYMBOL_GPL(bd_unlink_disk_holder
);
1324 * flush_disk - invalidates all buffer-cache entries on a disk
1326 * @bdev: struct block device to be flushed
1327 * @kill_dirty: flag to guide handling of dirty inodes
1329 * Invalidates all buffer-cache entries on a disk. It should be called
1330 * when a disk has been changed -- either by a media change or online
1333 static void flush_disk(struct block_device
*bdev
, bool kill_dirty
)
1335 if (__invalidate_device(bdev
, kill_dirty
)) {
1336 printk(KERN_WARNING
"VFS: busy inodes on changed media or "
1337 "resized disk %s\n",
1338 bdev
->bd_disk
? bdev
->bd_disk
->disk_name
: "");
1343 if (disk_part_scan_enabled(bdev
->bd_disk
))
1344 bdev
->bd_invalidated
= 1;
1348 * check_disk_size_change - checks for disk size change and adjusts bdev size.
1349 * @disk: struct gendisk to check
1350 * @bdev: struct bdev to adjust.
1351 * @verbose: if %true log a message about a size change if there is any
1353 * This routine checks to see if the bdev size does not match the disk size
1354 * and adjusts it if it differs. When shrinking the bdev size, its all caches
1357 void check_disk_size_change(struct gendisk
*disk
, struct block_device
*bdev
,
1360 loff_t disk_size
, bdev_size
;
1362 disk_size
= (loff_t
)get_capacity(disk
) << 9;
1363 bdev_size
= i_size_read(bdev
->bd_inode
);
1364 if (disk_size
!= bdev_size
) {
1367 "%s: detected capacity change from %lld to %lld\n",
1368 disk
->disk_name
, bdev_size
, disk_size
);
1370 i_size_write(bdev
->bd_inode
, disk_size
);
1371 if (bdev_size
> disk_size
)
1372 flush_disk(bdev
, false);
1377 * revalidate_disk - wrapper for lower-level driver's revalidate_disk call-back
1378 * @disk: struct gendisk to be revalidated
1380 * This routine is a wrapper for lower-level driver's revalidate_disk
1381 * call-backs. It is used to do common pre and post operations needed
1382 * for all revalidate_disk operations.
1384 int revalidate_disk(struct gendisk
*disk
)
1386 struct block_device
*bdev
;
1389 if (disk
->fops
->revalidate_disk
)
1390 ret
= disk
->fops
->revalidate_disk(disk
);
1391 bdev
= bdget_disk(disk
, 0);
1395 mutex_lock(&bdev
->bd_mutex
);
1396 check_disk_size_change(disk
, bdev
, ret
== 0);
1397 bdev
->bd_invalidated
= 0;
1398 mutex_unlock(&bdev
->bd_mutex
);
1402 EXPORT_SYMBOL(revalidate_disk
);
1405 * This routine checks whether a removable media has been changed,
1406 * and invalidates all buffer-cache-entries in that case. This
1407 * is a relatively slow routine, so we have to try to minimize using
1408 * it. Thus it is called only upon a 'mount' or 'open'. This
1409 * is the best way of combining speed and utility, I think.
1410 * People changing diskettes in the middle of an operation deserve
1413 int check_disk_change(struct block_device
*bdev
)
1415 struct gendisk
*disk
= bdev
->bd_disk
;
1416 const struct block_device_operations
*bdops
= disk
->fops
;
1417 unsigned int events
;
1419 events
= disk_clear_events(disk
, DISK_EVENT_MEDIA_CHANGE
|
1420 DISK_EVENT_EJECT_REQUEST
);
1421 if (!(events
& DISK_EVENT_MEDIA_CHANGE
))
1424 flush_disk(bdev
, true);
1425 if (bdops
->revalidate_disk
)
1426 bdops
->revalidate_disk(bdev
->bd_disk
);
1430 EXPORT_SYMBOL(check_disk_change
);
1432 void bd_set_size(struct block_device
*bdev
, loff_t size
)
1434 unsigned bsize
= bdev_logical_block_size(bdev
);
1436 inode_lock(bdev
->bd_inode
);
1437 i_size_write(bdev
->bd_inode
, size
);
1438 inode_unlock(bdev
->bd_inode
);
1439 while (bsize
< PAGE_SIZE
) {
1444 bdev
->bd_block_size
= bsize
;
1445 bdev
->bd_inode
->i_blkbits
= blksize_bits(bsize
);
1447 EXPORT_SYMBOL(bd_set_size
);
1449 static void __blkdev_put(struct block_device
*bdev
, fmode_t mode
, int for_part
);
1454 * mutex_lock(part->bd_mutex)
1455 * mutex_lock_nested(whole->bd_mutex, 1)
1458 static int __blkdev_get(struct block_device
*bdev
, fmode_t mode
, int for_part
)
1460 struct gendisk
*disk
;
1464 bool first_open
= false;
1466 if (mode
& FMODE_READ
)
1468 if (mode
& FMODE_WRITE
)
1471 * hooks: /n/, see "layering violations".
1474 ret
= devcgroup_inode_permission(bdev
->bd_inode
, perm
);
1484 disk
= bdev_get_gendisk(bdev
, &partno
);
1488 disk_block_events(disk
);
1489 mutex_lock_nested(&bdev
->bd_mutex
, for_part
);
1490 if (!bdev
->bd_openers
) {
1492 bdev
->bd_disk
= disk
;
1493 bdev
->bd_queue
= disk
->queue
;
1494 bdev
->bd_contains
= bdev
;
1495 bdev
->bd_partno
= partno
;
1499 bdev
->bd_part
= disk_get_part(disk
, partno
);
1504 if (disk
->fops
->open
) {
1505 ret
= disk
->fops
->open(bdev
, mode
);
1506 if (ret
== -ERESTARTSYS
) {
1507 /* Lost a race with 'disk' being
1508 * deleted, try again.
1511 disk_put_part(bdev
->bd_part
);
1512 bdev
->bd_part
= NULL
;
1513 bdev
->bd_disk
= NULL
;
1514 bdev
->bd_queue
= NULL
;
1515 mutex_unlock(&bdev
->bd_mutex
);
1516 disk_unblock_events(disk
);
1517 put_disk_and_module(disk
);
1523 bd_set_size(bdev
,(loff_t
)get_capacity(disk
)<<9);
1526 * If the device is invalidated, rescan partition
1527 * if open succeeded or failed with -ENOMEDIUM.
1528 * The latter is necessary to prevent ghost
1529 * partitions on a removed medium.
1531 if (bdev
->bd_invalidated
) {
1533 rescan_partitions(disk
, bdev
);
1534 else if (ret
== -ENOMEDIUM
)
1535 invalidate_partitions(disk
, bdev
);
1541 struct block_device
*whole
;
1542 whole
= bdget_disk(disk
, 0);
1547 ret
= __blkdev_get(whole
, mode
, 1);
1550 bdev
->bd_contains
= whole
;
1551 bdev
->bd_part
= disk_get_part(disk
, partno
);
1552 if (!(disk
->flags
& GENHD_FL_UP
) ||
1553 !bdev
->bd_part
|| !bdev
->bd_part
->nr_sects
) {
1557 bd_set_size(bdev
, (loff_t
)bdev
->bd_part
->nr_sects
<< 9);
1560 if (bdev
->bd_bdi
== &noop_backing_dev_info
)
1561 bdev
->bd_bdi
= bdi_get(disk
->queue
->backing_dev_info
);
1563 if (bdev
->bd_contains
== bdev
) {
1565 if (bdev
->bd_disk
->fops
->open
)
1566 ret
= bdev
->bd_disk
->fops
->open(bdev
, mode
);
1567 /* the same as first opener case, read comment there */
1568 if (bdev
->bd_invalidated
) {
1570 rescan_partitions(bdev
->bd_disk
, bdev
);
1571 else if (ret
== -ENOMEDIUM
)
1572 invalidate_partitions(bdev
->bd_disk
, bdev
);
1575 goto out_unlock_bdev
;
1580 bdev
->bd_part_count
++;
1581 mutex_unlock(&bdev
->bd_mutex
);
1582 disk_unblock_events(disk
);
1583 /* only one opener holds refs to the module and disk */
1585 put_disk_and_module(disk
);
1589 disk_put_part(bdev
->bd_part
);
1590 bdev
->bd_disk
= NULL
;
1591 bdev
->bd_part
= NULL
;
1592 bdev
->bd_queue
= NULL
;
1593 if (bdev
!= bdev
->bd_contains
)
1594 __blkdev_put(bdev
->bd_contains
, mode
, 1);
1595 bdev
->bd_contains
= NULL
;
1597 mutex_unlock(&bdev
->bd_mutex
);
1598 disk_unblock_events(disk
);
1599 put_disk_and_module(disk
);
1607 * blkdev_get - open a block device
1608 * @bdev: block_device to open
1609 * @mode: FMODE_* mask
1610 * @holder: exclusive holder identifier
1612 * Open @bdev with @mode. If @mode includes %FMODE_EXCL, @bdev is
1613 * open with exclusive access. Specifying %FMODE_EXCL with %NULL
1614 * @holder is invalid. Exclusive opens may nest for the same @holder.
1616 * On success, the reference count of @bdev is unchanged. On failure,
1623 * 0 on success, -errno on failure.
1625 int blkdev_get(struct block_device
*bdev
, fmode_t mode
, void *holder
)
1627 struct block_device
*whole
= NULL
;
1630 WARN_ON_ONCE((mode
& FMODE_EXCL
) && !holder
);
1632 if ((mode
& FMODE_EXCL
) && holder
) {
1633 whole
= bd_start_claiming(bdev
, holder
);
1634 if (IS_ERR(whole
)) {
1636 return PTR_ERR(whole
);
1640 res
= __blkdev_get(bdev
, mode
, 0);
1643 struct gendisk
*disk
= whole
->bd_disk
;
1645 /* finish claiming */
1646 mutex_lock(&bdev
->bd_mutex
);
1647 spin_lock(&bdev_lock
);
1650 BUG_ON(!bd_may_claim(bdev
, whole
, holder
));
1652 * Note that for a whole device bd_holders
1653 * will be incremented twice, and bd_holder
1654 * will be set to bd_may_claim before being
1657 whole
->bd_holders
++;
1658 whole
->bd_holder
= bd_may_claim
;
1660 bdev
->bd_holder
= holder
;
1663 /* tell others that we're done */
1664 BUG_ON(whole
->bd_claiming
!= holder
);
1665 whole
->bd_claiming
= NULL
;
1666 wake_up_bit(&whole
->bd_claiming
, 0);
1668 spin_unlock(&bdev_lock
);
1671 * Block event polling for write claims if requested. Any
1672 * write holder makes the write_holder state stick until
1673 * all are released. This is good enough and tracking
1674 * individual writeable reference is too fragile given the
1675 * way @mode is used in blkdev_get/put().
1677 if (!res
&& (mode
& FMODE_WRITE
) && !bdev
->bd_write_holder
&&
1678 (disk
->flags
& GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE
)) {
1679 bdev
->bd_write_holder
= true;
1680 disk_block_events(disk
);
1683 mutex_unlock(&bdev
->bd_mutex
);
1689 EXPORT_SYMBOL(blkdev_get
);
1692 * blkdev_get_by_path - open a block device by name
1693 * @path: path to the block device to open
1694 * @mode: FMODE_* mask
1695 * @holder: exclusive holder identifier
1697 * Open the blockdevice described by the device file at @path. @mode
1698 * and @holder are identical to blkdev_get().
1700 * On success, the returned block_device has reference count of one.
1706 * Pointer to block_device on success, ERR_PTR(-errno) on failure.
1708 struct block_device
*blkdev_get_by_path(const char *path
, fmode_t mode
,
1711 struct block_device
*bdev
;
1714 bdev
= lookup_bdev(path
);
1718 err
= blkdev_get(bdev
, mode
, holder
);
1720 return ERR_PTR(err
);
1722 if ((mode
& FMODE_WRITE
) && bdev_read_only(bdev
)) {
1723 blkdev_put(bdev
, mode
);
1724 return ERR_PTR(-EACCES
);
1729 EXPORT_SYMBOL(blkdev_get_by_path
);
1732 * blkdev_get_by_dev - open a block device by device number
1733 * @dev: device number of block device to open
1734 * @mode: FMODE_* mask
1735 * @holder: exclusive holder identifier
1737 * Open the blockdevice described by device number @dev. @mode and
1738 * @holder are identical to blkdev_get().
1740 * Use it ONLY if you really do not have anything better - i.e. when
1741 * you are behind a truly sucky interface and all you are given is a
1742 * device number. _Never_ to be used for internal purposes. If you
1743 * ever need it - reconsider your API.
1745 * On success, the returned block_device has reference count of one.
1751 * Pointer to block_device on success, ERR_PTR(-errno) on failure.
1753 struct block_device
*blkdev_get_by_dev(dev_t dev
, fmode_t mode
, void *holder
)
1755 struct block_device
*bdev
;
1760 return ERR_PTR(-ENOMEM
);
1762 err
= blkdev_get(bdev
, mode
, holder
);
1764 return ERR_PTR(err
);
1768 EXPORT_SYMBOL(blkdev_get_by_dev
);
1770 static int blkdev_open(struct inode
* inode
, struct file
* filp
)
1772 struct block_device
*bdev
;
1775 * Preserve backwards compatibility and allow large file access
1776 * even if userspace doesn't ask for it explicitly. Some mkfs
1777 * binary needs it. We might want to drop this workaround
1778 * during an unstable branch.
1780 filp
->f_flags
|= O_LARGEFILE
;
1782 filp
->f_mode
|= FMODE_NOWAIT
;
1784 if (filp
->f_flags
& O_NDELAY
)
1785 filp
->f_mode
|= FMODE_NDELAY
;
1786 if (filp
->f_flags
& O_EXCL
)
1787 filp
->f_mode
|= FMODE_EXCL
;
1788 if ((filp
->f_flags
& O_ACCMODE
) == 3)
1789 filp
->f_mode
|= FMODE_WRITE_IOCTL
;
1791 bdev
= bd_acquire(inode
);
1795 filp
->f_mapping
= bdev
->bd_inode
->i_mapping
;
1796 filp
->f_wb_err
= filemap_sample_wb_err(filp
->f_mapping
);
1798 return blkdev_get(bdev
, filp
->f_mode
, filp
);
1801 static void __blkdev_put(struct block_device
*bdev
, fmode_t mode
, int for_part
)
1803 struct gendisk
*disk
= bdev
->bd_disk
;
1804 struct block_device
*victim
= NULL
;
1806 mutex_lock_nested(&bdev
->bd_mutex
, for_part
);
1808 bdev
->bd_part_count
--;
1810 if (!--bdev
->bd_openers
) {
1811 WARN_ON_ONCE(bdev
->bd_holders
);
1812 sync_blockdev(bdev
);
1815 bdev_write_inode(bdev
);
1817 if (bdev
->bd_contains
== bdev
) {
1818 if (disk
->fops
->release
)
1819 disk
->fops
->release(disk
, mode
);
1821 if (!bdev
->bd_openers
) {
1822 disk_put_part(bdev
->bd_part
);
1823 bdev
->bd_part
= NULL
;
1824 bdev
->bd_disk
= NULL
;
1825 if (bdev
!= bdev
->bd_contains
)
1826 victim
= bdev
->bd_contains
;
1827 bdev
->bd_contains
= NULL
;
1829 put_disk_and_module(disk
);
1831 mutex_unlock(&bdev
->bd_mutex
);
1834 __blkdev_put(victim
, mode
, 1);
1837 void blkdev_put(struct block_device
*bdev
, fmode_t mode
)
1839 mutex_lock(&bdev
->bd_mutex
);
1841 if (mode
& FMODE_EXCL
) {
1845 * Release a claim on the device. The holder fields
1846 * are protected with bdev_lock. bd_mutex is to
1847 * synchronize disk_holder unlinking.
1849 spin_lock(&bdev_lock
);
1851 WARN_ON_ONCE(--bdev
->bd_holders
< 0);
1852 WARN_ON_ONCE(--bdev
->bd_contains
->bd_holders
< 0);
1854 /* bd_contains might point to self, check in a separate step */
1855 if ((bdev_free
= !bdev
->bd_holders
))
1856 bdev
->bd_holder
= NULL
;
1857 if (!bdev
->bd_contains
->bd_holders
)
1858 bdev
->bd_contains
->bd_holder
= NULL
;
1860 spin_unlock(&bdev_lock
);
1863 * If this was the last claim, remove holder link and
1864 * unblock evpoll if it was a write holder.
1866 if (bdev_free
&& bdev
->bd_write_holder
) {
1867 disk_unblock_events(bdev
->bd_disk
);
1868 bdev
->bd_write_holder
= false;
1873 * Trigger event checking and tell drivers to flush MEDIA_CHANGE
1874 * event. This is to ensure detection of media removal commanded
1875 * from userland - e.g. eject(1).
1877 disk_flush_events(bdev
->bd_disk
, DISK_EVENT_MEDIA_CHANGE
);
1879 mutex_unlock(&bdev
->bd_mutex
);
1881 __blkdev_put(bdev
, mode
, 0);
1883 EXPORT_SYMBOL(blkdev_put
);
1885 static int blkdev_close(struct inode
* inode
, struct file
* filp
)
1887 struct block_device
*bdev
= I_BDEV(bdev_file_inode(filp
));
1888 blkdev_put(bdev
, filp
->f_mode
);
1892 static long block_ioctl(struct file
*file
, unsigned cmd
, unsigned long arg
)
1894 struct block_device
*bdev
= I_BDEV(bdev_file_inode(file
));
1895 fmode_t mode
= file
->f_mode
;
1898 * O_NDELAY can be altered using fcntl(.., F_SETFL, ..), so we have
1899 * to updated it before every ioctl.
1901 if (file
->f_flags
& O_NDELAY
)
1902 mode
|= FMODE_NDELAY
;
1904 mode
&= ~FMODE_NDELAY
;
1906 return blkdev_ioctl(bdev
, mode
, cmd
, arg
);
1910 * Write data to the block device. Only intended for the block device itself
1911 * and the raw driver which basically is a fake block device.
1913 * Does not take i_mutex for the write and thus is not for general purpose
1916 ssize_t
blkdev_write_iter(struct kiocb
*iocb
, struct iov_iter
*from
)
1918 struct file
*file
= iocb
->ki_filp
;
1919 struct inode
*bd_inode
= bdev_file_inode(file
);
1920 loff_t size
= i_size_read(bd_inode
);
1921 struct blk_plug plug
;
1924 if (bdev_read_only(I_BDEV(bd_inode
)))
1927 if (!iov_iter_count(from
))
1930 if (iocb
->ki_pos
>= size
)
1933 if ((iocb
->ki_flags
& (IOCB_NOWAIT
| IOCB_DIRECT
)) == IOCB_NOWAIT
)
1936 iov_iter_truncate(from
, size
- iocb
->ki_pos
);
1938 blk_start_plug(&plug
);
1939 ret
= __generic_file_write_iter(iocb
, from
);
1941 ret
= generic_write_sync(iocb
, ret
);
1942 blk_finish_plug(&plug
);
1945 EXPORT_SYMBOL_GPL(blkdev_write_iter
);
1947 ssize_t
blkdev_read_iter(struct kiocb
*iocb
, struct iov_iter
*to
)
1949 struct file
*file
= iocb
->ki_filp
;
1950 struct inode
*bd_inode
= bdev_file_inode(file
);
1951 loff_t size
= i_size_read(bd_inode
);
1952 loff_t pos
= iocb
->ki_pos
;
1958 iov_iter_truncate(to
, size
);
1959 return generic_file_read_iter(iocb
, to
);
1961 EXPORT_SYMBOL_GPL(blkdev_read_iter
);
1964 * Try to release a page associated with block device when the system
1965 * is under memory pressure.
1967 static int blkdev_releasepage(struct page
*page
, gfp_t wait
)
1969 struct super_block
*super
= BDEV_I(page
->mapping
->host
)->bdev
.bd_super
;
1971 if (super
&& super
->s_op
->bdev_try_to_free_page
)
1972 return super
->s_op
->bdev_try_to_free_page(super
, page
, wait
);
1974 return try_to_free_buffers(page
);
1977 static int blkdev_writepages(struct address_space
*mapping
,
1978 struct writeback_control
*wbc
)
1980 return generic_writepages(mapping
, wbc
);
1983 static const struct address_space_operations def_blk_aops
= {
1984 .readpage
= blkdev_readpage
,
1985 .readpages
= blkdev_readpages
,
1986 .writepage
= blkdev_writepage
,
1987 .write_begin
= blkdev_write_begin
,
1988 .write_end
= blkdev_write_end
,
1989 .writepages
= blkdev_writepages
,
1990 .releasepage
= blkdev_releasepage
,
1991 .direct_IO
= blkdev_direct_IO
,
1992 .migratepage
= buffer_migrate_page_norefs
,
1993 .is_dirty_writeback
= buffer_check_dirty_writeback
,
1996 #define BLKDEV_FALLOC_FL_SUPPORTED \
1997 (FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE | \
1998 FALLOC_FL_ZERO_RANGE | FALLOC_FL_NO_HIDE_STALE)
2000 static long blkdev_fallocate(struct file
*file
, int mode
, loff_t start
,
2003 struct block_device
*bdev
= I_BDEV(bdev_file_inode(file
));
2004 struct address_space
*mapping
;
2005 loff_t end
= start
+ len
- 1;
2009 /* Fail if we don't recognize the flags. */
2010 if (mode
& ~BLKDEV_FALLOC_FL_SUPPORTED
)
2013 /* Don't go off the end of the device. */
2014 isize
= i_size_read(bdev
->bd_inode
);
2018 if (mode
& FALLOC_FL_KEEP_SIZE
) {
2019 len
= isize
- start
;
2020 end
= start
+ len
- 1;
2026 * Don't allow IO that isn't aligned to logical block size.
2028 if ((start
| len
) & (bdev_logical_block_size(bdev
) - 1))
2031 /* Invalidate the page cache, including dirty pages. */
2032 mapping
= bdev
->bd_inode
->i_mapping
;
2033 truncate_inode_pages_range(mapping
, start
, end
);
2036 case FALLOC_FL_ZERO_RANGE
:
2037 case FALLOC_FL_ZERO_RANGE
| FALLOC_FL_KEEP_SIZE
:
2038 error
= blkdev_issue_zeroout(bdev
, start
>> 9, len
>> 9,
2039 GFP_KERNEL
, BLKDEV_ZERO_NOUNMAP
);
2041 case FALLOC_FL_PUNCH_HOLE
| FALLOC_FL_KEEP_SIZE
:
2042 error
= blkdev_issue_zeroout(bdev
, start
>> 9, len
>> 9,
2043 GFP_KERNEL
, BLKDEV_ZERO_NOFALLBACK
);
2045 case FALLOC_FL_PUNCH_HOLE
| FALLOC_FL_KEEP_SIZE
| FALLOC_FL_NO_HIDE_STALE
:
2046 error
= blkdev_issue_discard(bdev
, start
>> 9, len
>> 9,
2056 * Invalidate again; if someone wandered in and dirtied a page,
2057 * the caller will be given -EBUSY. The third argument is
2058 * inclusive, so the rounding here is safe.
2060 return invalidate_inode_pages2_range(mapping
,
2061 start
>> PAGE_SHIFT
,
2065 const struct file_operations def_blk_fops
= {
2066 .open
= blkdev_open
,
2067 .release
= blkdev_close
,
2068 .llseek
= block_llseek
,
2069 .read_iter
= blkdev_read_iter
,
2070 .write_iter
= blkdev_write_iter
,
2071 .mmap
= generic_file_mmap
,
2072 .fsync
= blkdev_fsync
,
2073 .unlocked_ioctl
= block_ioctl
,
2074 #ifdef CONFIG_COMPAT
2075 .compat_ioctl
= compat_blkdev_ioctl
,
2077 .splice_read
= generic_file_splice_read
,
2078 .splice_write
= iter_file_splice_write
,
2079 .fallocate
= blkdev_fallocate
,
2082 int ioctl_by_bdev(struct block_device
*bdev
, unsigned cmd
, unsigned long arg
)
2085 mm_segment_t old_fs
= get_fs();
2087 res
= blkdev_ioctl(bdev
, 0, cmd
, arg
);
2092 EXPORT_SYMBOL(ioctl_by_bdev
);
2095 * lookup_bdev - lookup a struct block_device by name
2096 * @pathname: special file representing the block device
2098 * Get a reference to the blockdevice at @pathname in the current
2099 * namespace if possible and return it. Return ERR_PTR(error)
2102 struct block_device
*lookup_bdev(const char *pathname
)
2104 struct block_device
*bdev
;
2105 struct inode
*inode
;
2109 if (!pathname
|| !*pathname
)
2110 return ERR_PTR(-EINVAL
);
2112 error
= kern_path(pathname
, LOOKUP_FOLLOW
, &path
);
2114 return ERR_PTR(error
);
2116 inode
= d_backing_inode(path
.dentry
);
2118 if (!S_ISBLK(inode
->i_mode
))
2121 if (!may_open_dev(&path
))
2124 bdev
= bd_acquire(inode
);
2131 bdev
= ERR_PTR(error
);
2134 EXPORT_SYMBOL(lookup_bdev
);
2136 int __invalidate_device(struct block_device
*bdev
, bool kill_dirty
)
2138 struct super_block
*sb
= get_super(bdev
);
2143 * no need to lock the super, get_super holds the
2144 * read mutex so the filesystem cannot go away
2145 * under us (->put_super runs with the write lock
2148 shrink_dcache_sb(sb
);
2149 res
= invalidate_inodes(sb
, kill_dirty
);
2152 invalidate_bdev(bdev
);
2155 EXPORT_SYMBOL(__invalidate_device
);
2157 void iterate_bdevs(void (*func
)(struct block_device
*, void *), void *arg
)
2159 struct inode
*inode
, *old_inode
= NULL
;
2161 spin_lock(&blockdev_superblock
->s_inode_list_lock
);
2162 list_for_each_entry(inode
, &blockdev_superblock
->s_inodes
, i_sb_list
) {
2163 struct address_space
*mapping
= inode
->i_mapping
;
2164 struct block_device
*bdev
;
2166 spin_lock(&inode
->i_lock
);
2167 if (inode
->i_state
& (I_FREEING
|I_WILL_FREE
|I_NEW
) ||
2168 mapping
->nrpages
== 0) {
2169 spin_unlock(&inode
->i_lock
);
2173 spin_unlock(&inode
->i_lock
);
2174 spin_unlock(&blockdev_superblock
->s_inode_list_lock
);
2176 * We hold a reference to 'inode' so it couldn't have been
2177 * removed from s_inodes list while we dropped the
2178 * s_inode_list_lock We cannot iput the inode now as we can
2179 * be holding the last reference and we cannot iput it under
2180 * s_inode_list_lock. So we keep the reference and iput it
2185 bdev
= I_BDEV(inode
);
2187 mutex_lock(&bdev
->bd_mutex
);
2188 if (bdev
->bd_openers
)
2190 mutex_unlock(&bdev
->bd_mutex
);
2192 spin_lock(&blockdev_superblock
->s_inode_list_lock
);
2194 spin_unlock(&blockdev_superblock
->s_inode_list_lock
);