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 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
, *bvec
;
208 loff_t pos
= iocb
->ki_pos
;
209 bool should_dirty
= false;
214 struct bvec_iter_all iter_all
;
216 if ((pos
| iov_iter_alignment(iter
)) &
217 (bdev_logical_block_size(bdev
) - 1))
220 if (nr_pages
<= DIO_INLINE_BIO_VECS
)
223 vecs
= kmalloc_array(nr_pages
, sizeof(struct bio_vec
),
229 bio_init(&bio
, vecs
, nr_pages
);
230 bio_set_dev(&bio
, bdev
);
231 bio
.bi_iter
.bi_sector
= pos
>> 9;
232 bio
.bi_write_hint
= iocb
->ki_hint
;
233 bio
.bi_private
= current
;
234 bio
.bi_end_io
= blkdev_bio_end_io_simple
;
235 bio
.bi_ioprio
= iocb
->ki_ioprio
;
237 ret
= bio_iov_iter_get_pages(&bio
, iter
);
240 ret
= bio
.bi_iter
.bi_size
;
242 if (iov_iter_rw(iter
) == READ
) {
243 bio
.bi_opf
= REQ_OP_READ
;
244 if (iter_is_iovec(iter
))
247 bio
.bi_opf
= dio_bio_write_op(iocb
);
248 task_io_account_write(ret
);
250 if (iocb
->ki_flags
& IOCB_HIPRI
)
251 bio_set_polled(&bio
, iocb
);
253 qc
= submit_bio(&bio
);
255 set_current_state(TASK_UNINTERRUPTIBLE
);
256 if (!READ_ONCE(bio
.bi_private
))
258 if (!(iocb
->ki_flags
& IOCB_HIPRI
) ||
259 !blk_poll(bdev_get_queue(bdev
), qc
, true))
262 __set_current_state(TASK_RUNNING
);
264 bio_for_each_segment_all(bvec
, &bio
, i
, iter_all
) {
265 if (should_dirty
&& !PageCompound(bvec
->bv_page
))
266 set_page_dirty_lock(bvec
->bv_page
);
267 if (!bio_flagged(&bio
, BIO_NO_PAGE_REF
))
268 put_page(bvec
->bv_page
);
271 if (unlikely(bio
.bi_status
))
272 ret
= blk_status_to_errno(bio
.bi_status
);
275 if (vecs
!= inline_vecs
)
286 struct task_struct
*waiter
;
291 bool should_dirty
: 1;
296 static struct bio_set blkdev_dio_pool
;
298 static int blkdev_iopoll(struct kiocb
*kiocb
, bool wait
)
300 struct block_device
*bdev
= I_BDEV(kiocb
->ki_filp
->f_mapping
->host
);
301 struct request_queue
*q
= bdev_get_queue(bdev
);
303 return blk_poll(q
, READ_ONCE(kiocb
->ki_cookie
), wait
);
306 static void blkdev_bio_end_io(struct bio
*bio
)
308 struct blkdev_dio
*dio
= bio
->bi_private
;
309 bool should_dirty
= dio
->should_dirty
;
311 if (bio
->bi_status
&& !dio
->bio
.bi_status
)
312 dio
->bio
.bi_status
= bio
->bi_status
;
314 if (!dio
->multi_bio
|| atomic_dec_and_test(&dio
->ref
)) {
316 struct kiocb
*iocb
= dio
->iocb
;
319 if (likely(!dio
->bio
.bi_status
)) {
323 ret
= blk_status_to_errno(dio
->bio
.bi_status
);
326 dio
->iocb
->ki_complete(iocb
, ret
, 0);
330 struct task_struct
*waiter
= dio
->waiter
;
332 WRITE_ONCE(dio
->waiter
, NULL
);
333 blk_wake_io_task(waiter
);
338 bio_check_pages_dirty(bio
);
340 if (!bio_flagged(bio
, BIO_NO_PAGE_REF
)) {
341 struct bvec_iter_all iter_all
;
342 struct bio_vec
*bvec
;
345 bio_for_each_segment_all(bvec
, bio
, i
, iter_all
)
346 put_page(bvec
->bv_page
);
353 __blkdev_direct_IO(struct kiocb
*iocb
, struct iov_iter
*iter
, int nr_pages
)
355 struct file
*file
= iocb
->ki_filp
;
356 struct inode
*inode
= bdev_file_inode(file
);
357 struct block_device
*bdev
= I_BDEV(inode
);
358 struct blk_plug plug
;
359 struct blkdev_dio
*dio
;
361 bool is_poll
= (iocb
->ki_flags
& IOCB_HIPRI
) != 0;
362 bool is_read
= (iov_iter_rw(iter
) == READ
), is_sync
;
363 loff_t pos
= iocb
->ki_pos
;
364 blk_qc_t qc
= BLK_QC_T_NONE
;
367 if ((pos
| iov_iter_alignment(iter
)) &
368 (bdev_logical_block_size(bdev
) - 1))
371 bio
= bio_alloc_bioset(GFP_KERNEL
, nr_pages
, &blkdev_dio_pool
);
373 dio
= container_of(bio
, struct blkdev_dio
, bio
);
374 dio
->is_sync
= is_sync
= is_sync_kiocb(iocb
);
376 dio
->waiter
= current
;
383 dio
->multi_bio
= false;
384 dio
->should_dirty
= is_read
&& iter_is_iovec(iter
);
387 * Don't plug for HIPRI/polled IO, as those should go straight
391 blk_start_plug(&plug
);
394 bio_set_dev(bio
, bdev
);
395 bio
->bi_iter
.bi_sector
= pos
>> 9;
396 bio
->bi_write_hint
= iocb
->ki_hint
;
397 bio
->bi_private
= dio
;
398 bio
->bi_end_io
= blkdev_bio_end_io
;
399 bio
->bi_ioprio
= iocb
->ki_ioprio
;
401 ret
= bio_iov_iter_get_pages(bio
, iter
);
403 bio
->bi_status
= BLK_STS_IOERR
;
409 bio
->bi_opf
= REQ_OP_READ
;
410 if (dio
->should_dirty
)
411 bio_set_pages_dirty(bio
);
413 bio
->bi_opf
= dio_bio_write_op(iocb
);
414 task_io_account_write(bio
->bi_iter
.bi_size
);
417 dio
->size
+= bio
->bi_iter
.bi_size
;
418 pos
+= bio
->bi_iter
.bi_size
;
420 nr_pages
= iov_iter_npages(iter
, BIO_MAX_PAGES
);
424 if (iocb
->ki_flags
& IOCB_HIPRI
) {
425 bio_set_polled(bio
, iocb
);
429 qc
= submit_bio(bio
);
432 WRITE_ONCE(iocb
->ki_cookie
, qc
);
436 if (!dio
->multi_bio
) {
438 * AIO needs an extra reference to ensure the dio
439 * structure which is embedded into the first bio
444 dio
->multi_bio
= true;
445 atomic_set(&dio
->ref
, 2);
447 atomic_inc(&dio
->ref
);
451 bio
= bio_alloc(GFP_KERNEL
, nr_pages
);
455 blk_finish_plug(&plug
);
461 set_current_state(TASK_UNINTERRUPTIBLE
);
462 if (!READ_ONCE(dio
->waiter
))
465 if (!(iocb
->ki_flags
& IOCB_HIPRI
) ||
466 !blk_poll(bdev_get_queue(bdev
), qc
, true))
469 __set_current_state(TASK_RUNNING
);
472 ret
= blk_status_to_errno(dio
->bio
.bi_status
);
481 blkdev_direct_IO(struct kiocb
*iocb
, struct iov_iter
*iter
)
485 nr_pages
= iov_iter_npages(iter
, BIO_MAX_PAGES
+ 1);
488 if (is_sync_kiocb(iocb
) && nr_pages
<= BIO_MAX_PAGES
)
489 return __blkdev_direct_IO_simple(iocb
, iter
, nr_pages
);
491 return __blkdev_direct_IO(iocb
, iter
, min(nr_pages
, BIO_MAX_PAGES
));
494 static __init
int blkdev_init(void)
496 return bioset_init(&blkdev_dio_pool
, 4, offsetof(struct blkdev_dio
, bio
), BIOSET_NEED_BVECS
);
498 module_init(blkdev_init
);
500 int __sync_blockdev(struct block_device
*bdev
, int wait
)
505 return filemap_flush(bdev
->bd_inode
->i_mapping
);
506 return filemap_write_and_wait(bdev
->bd_inode
->i_mapping
);
510 * Write out and wait upon all the dirty data associated with a block
511 * device via its mapping. Does not take the superblock lock.
513 int sync_blockdev(struct block_device
*bdev
)
515 return __sync_blockdev(bdev
, 1);
517 EXPORT_SYMBOL(sync_blockdev
);
520 * Write out and wait upon all dirty data associated with this
521 * device. Filesystem data as well as the underlying block
522 * device. Takes the superblock lock.
524 int fsync_bdev(struct block_device
*bdev
)
526 struct super_block
*sb
= get_super(bdev
);
528 int res
= sync_filesystem(sb
);
532 return sync_blockdev(bdev
);
534 EXPORT_SYMBOL(fsync_bdev
);
537 * freeze_bdev -- lock a filesystem and force it into a consistent state
538 * @bdev: blockdevice to lock
540 * If a superblock is found on this device, we take the s_umount semaphore
541 * on it to make sure nobody unmounts until the snapshot creation is done.
542 * The reference counter (bd_fsfreeze_count) guarantees that only the last
543 * unfreeze process can unfreeze the frozen filesystem actually when multiple
544 * freeze requests arrive simultaneously. It counts up in freeze_bdev() and
545 * count down in thaw_bdev(). When it becomes 0, thaw_bdev() will unfreeze
548 struct super_block
*freeze_bdev(struct block_device
*bdev
)
550 struct super_block
*sb
;
553 mutex_lock(&bdev
->bd_fsfreeze_mutex
);
554 if (++bdev
->bd_fsfreeze_count
> 1) {
556 * We don't even need to grab a reference - the first call
557 * to freeze_bdev grab an active reference and only the last
558 * thaw_bdev drops it.
560 sb
= get_super(bdev
);
563 mutex_unlock(&bdev
->bd_fsfreeze_mutex
);
567 sb
= get_active_super(bdev
);
570 if (sb
->s_op
->freeze_super
)
571 error
= sb
->s_op
->freeze_super(sb
);
573 error
= freeze_super(sb
);
575 deactivate_super(sb
);
576 bdev
->bd_fsfreeze_count
--;
577 mutex_unlock(&bdev
->bd_fsfreeze_mutex
);
578 return ERR_PTR(error
);
580 deactivate_super(sb
);
583 mutex_unlock(&bdev
->bd_fsfreeze_mutex
);
584 return sb
; /* thaw_bdev releases s->s_umount */
586 EXPORT_SYMBOL(freeze_bdev
);
589 * thaw_bdev -- unlock filesystem
590 * @bdev: blockdevice to unlock
591 * @sb: associated superblock
593 * Unlocks the filesystem and marks it writeable again after freeze_bdev().
595 int thaw_bdev(struct block_device
*bdev
, struct super_block
*sb
)
599 mutex_lock(&bdev
->bd_fsfreeze_mutex
);
600 if (!bdev
->bd_fsfreeze_count
)
604 if (--bdev
->bd_fsfreeze_count
> 0)
610 if (sb
->s_op
->thaw_super
)
611 error
= sb
->s_op
->thaw_super(sb
);
613 error
= thaw_super(sb
);
615 bdev
->bd_fsfreeze_count
++;
617 mutex_unlock(&bdev
->bd_fsfreeze_mutex
);
620 EXPORT_SYMBOL(thaw_bdev
);
622 static int blkdev_writepage(struct page
*page
, struct writeback_control
*wbc
)
624 return block_write_full_page(page
, blkdev_get_block
, wbc
);
627 static int blkdev_readpage(struct file
* file
, struct page
* page
)
629 return block_read_full_page(page
, blkdev_get_block
);
632 static int blkdev_readpages(struct file
*file
, struct address_space
*mapping
,
633 struct list_head
*pages
, unsigned nr_pages
)
635 return mpage_readpages(mapping
, pages
, nr_pages
, blkdev_get_block
);
638 static int blkdev_write_begin(struct file
*file
, struct address_space
*mapping
,
639 loff_t pos
, unsigned len
, unsigned flags
,
640 struct page
**pagep
, void **fsdata
)
642 return block_write_begin(mapping
, pos
, len
, flags
, pagep
,
646 static int blkdev_write_end(struct file
*file
, struct address_space
*mapping
,
647 loff_t pos
, unsigned len
, unsigned copied
,
648 struct page
*page
, void *fsdata
)
651 ret
= block_write_end(file
, mapping
, pos
, len
, copied
, page
, fsdata
);
661 * for a block special file file_inode(file)->i_size is zero
662 * so we compute the size by hand (just as in block_read/write above)
664 static loff_t
block_llseek(struct file
*file
, loff_t offset
, int whence
)
666 struct inode
*bd_inode
= bdev_file_inode(file
);
669 inode_lock(bd_inode
);
670 retval
= fixed_size_llseek(file
, offset
, whence
, i_size_read(bd_inode
));
671 inode_unlock(bd_inode
);
675 int blkdev_fsync(struct file
*filp
, loff_t start
, loff_t end
, int datasync
)
677 struct inode
*bd_inode
= bdev_file_inode(filp
);
678 struct block_device
*bdev
= I_BDEV(bd_inode
);
681 error
= file_write_and_wait_range(filp
, start
, end
);
686 * There is no need to serialise calls to blkdev_issue_flush with
687 * i_mutex and doing so causes performance issues with concurrent
688 * O_SYNC writers to a block device.
690 error
= blkdev_issue_flush(bdev
, GFP_KERNEL
, NULL
);
691 if (error
== -EOPNOTSUPP
)
696 EXPORT_SYMBOL(blkdev_fsync
);
699 * bdev_read_page() - Start reading a page from a block device
700 * @bdev: The device to read the page from
701 * @sector: The offset on the device to read the page to (need not be aligned)
702 * @page: The page to read
704 * On entry, the page should be locked. It will be unlocked when the page
705 * has been read. If the block driver implements rw_page synchronously,
706 * that will be true on exit from this function, but it need not be.
708 * Errors returned by this function are usually "soft", eg out of memory, or
709 * queue full; callers should try a different route to read this page rather
710 * than propagate an error back up the stack.
712 * Return: negative errno if an error occurs, 0 if submission was successful.
714 int bdev_read_page(struct block_device
*bdev
, sector_t sector
,
717 const struct block_device_operations
*ops
= bdev
->bd_disk
->fops
;
718 int result
= -EOPNOTSUPP
;
720 if (!ops
->rw_page
|| bdev_get_integrity(bdev
))
723 result
= blk_queue_enter(bdev
->bd_queue
, 0);
726 result
= ops
->rw_page(bdev
, sector
+ get_start_sect(bdev
), page
,
728 blk_queue_exit(bdev
->bd_queue
);
731 EXPORT_SYMBOL_GPL(bdev_read_page
);
734 * bdev_write_page() - Start writing a page to a block device
735 * @bdev: The device to write the page to
736 * @sector: The offset on the device to write the page to (need not be aligned)
737 * @page: The page to write
738 * @wbc: The writeback_control for the write
740 * On entry, the page should be locked and not currently under writeback.
741 * On exit, if the write started successfully, the page will be unlocked and
742 * under writeback. If the write failed already (eg the driver failed to
743 * queue the page to the device), the page will still be locked. If the
744 * caller is a ->writepage implementation, it will need to unlock the page.
746 * Errors returned by this function are usually "soft", eg out of memory, or
747 * queue full; callers should try a different route to write this page rather
748 * than propagate an error back up the stack.
750 * Return: negative errno if an error occurs, 0 if submission was successful.
752 int bdev_write_page(struct block_device
*bdev
, sector_t sector
,
753 struct page
*page
, struct writeback_control
*wbc
)
756 const struct block_device_operations
*ops
= bdev
->bd_disk
->fops
;
758 if (!ops
->rw_page
|| bdev_get_integrity(bdev
))
760 result
= blk_queue_enter(bdev
->bd_queue
, 0);
764 set_page_writeback(page
);
765 result
= ops
->rw_page(bdev
, sector
+ get_start_sect(bdev
), page
,
768 end_page_writeback(page
);
770 clean_page_buffers(page
);
773 blk_queue_exit(bdev
->bd_queue
);
776 EXPORT_SYMBOL_GPL(bdev_write_page
);
782 static __cacheline_aligned_in_smp
DEFINE_SPINLOCK(bdev_lock
);
783 static struct kmem_cache
* bdev_cachep __read_mostly
;
785 static struct inode
*bdev_alloc_inode(struct super_block
*sb
)
787 struct bdev_inode
*ei
= kmem_cache_alloc(bdev_cachep
, GFP_KERNEL
);
790 return &ei
->vfs_inode
;
793 static void bdev_free_inode(struct inode
*inode
)
795 kmem_cache_free(bdev_cachep
, BDEV_I(inode
));
798 static void init_once(void *foo
)
800 struct bdev_inode
*ei
= (struct bdev_inode
*) foo
;
801 struct block_device
*bdev
= &ei
->bdev
;
803 memset(bdev
, 0, sizeof(*bdev
));
804 mutex_init(&bdev
->bd_mutex
);
805 INIT_LIST_HEAD(&bdev
->bd_list
);
807 INIT_LIST_HEAD(&bdev
->bd_holder_disks
);
809 bdev
->bd_bdi
= &noop_backing_dev_info
;
810 inode_init_once(&ei
->vfs_inode
);
811 /* Initialize mutex for freeze. */
812 mutex_init(&bdev
->bd_fsfreeze_mutex
);
815 static void bdev_evict_inode(struct inode
*inode
)
817 struct block_device
*bdev
= &BDEV_I(inode
)->bdev
;
818 truncate_inode_pages_final(&inode
->i_data
);
819 invalidate_inode_buffers(inode
); /* is it needed here? */
821 spin_lock(&bdev_lock
);
822 list_del_init(&bdev
->bd_list
);
823 spin_unlock(&bdev_lock
);
824 /* Detach inode from wb early as bdi_put() may free bdi->wb */
825 inode_detach_wb(inode
);
826 if (bdev
->bd_bdi
!= &noop_backing_dev_info
) {
827 bdi_put(bdev
->bd_bdi
);
828 bdev
->bd_bdi
= &noop_backing_dev_info
;
832 static const struct super_operations bdev_sops
= {
833 .statfs
= simple_statfs
,
834 .alloc_inode
= bdev_alloc_inode
,
835 .free_inode
= bdev_free_inode
,
836 .drop_inode
= generic_delete_inode
,
837 .evict_inode
= bdev_evict_inode
,
840 static struct dentry
*bd_mount(struct file_system_type
*fs_type
,
841 int flags
, const char *dev_name
, void *data
)
844 dent
= mount_pseudo(fs_type
, "bdev:", &bdev_sops
, NULL
, BDEVFS_MAGIC
);
846 dent
->d_sb
->s_iflags
|= SB_I_CGROUPWB
;
850 static struct file_system_type bd_type
= {
853 .kill_sb
= kill_anon_super
,
856 struct super_block
*blockdev_superblock __read_mostly
;
857 EXPORT_SYMBOL_GPL(blockdev_superblock
);
859 void __init
bdev_cache_init(void)
862 static struct vfsmount
*bd_mnt
;
864 bdev_cachep
= kmem_cache_create("bdev_cache", sizeof(struct bdev_inode
),
865 0, (SLAB_HWCACHE_ALIGN
|SLAB_RECLAIM_ACCOUNT
|
866 SLAB_MEM_SPREAD
|SLAB_ACCOUNT
|SLAB_PANIC
),
868 err
= register_filesystem(&bd_type
);
870 panic("Cannot register bdev pseudo-fs");
871 bd_mnt
= kern_mount(&bd_type
);
873 panic("Cannot create bdev pseudo-fs");
874 blockdev_superblock
= bd_mnt
->mnt_sb
; /* For writeback */
878 * Most likely _very_ bad one - but then it's hardly critical for small
879 * /dev and can be fixed when somebody will need really large one.
880 * Keep in mind that it will be fed through icache hash function too.
882 static inline unsigned long hash(dev_t dev
)
884 return MAJOR(dev
)+MINOR(dev
);
887 static int bdev_test(struct inode
*inode
, void *data
)
889 return BDEV_I(inode
)->bdev
.bd_dev
== *(dev_t
*)data
;
892 static int bdev_set(struct inode
*inode
, void *data
)
894 BDEV_I(inode
)->bdev
.bd_dev
= *(dev_t
*)data
;
898 static LIST_HEAD(all_bdevs
);
901 * If there is a bdev inode for this device, unhash it so that it gets evicted
902 * as soon as last inode reference is dropped.
904 void bdev_unhash_inode(dev_t dev
)
908 inode
= ilookup5(blockdev_superblock
, hash(dev
), bdev_test
, &dev
);
910 remove_inode_hash(inode
);
915 struct block_device
*bdget(dev_t dev
)
917 struct block_device
*bdev
;
920 inode
= iget5_locked(blockdev_superblock
, hash(dev
),
921 bdev_test
, bdev_set
, &dev
);
926 bdev
= &BDEV_I(inode
)->bdev
;
928 if (inode
->i_state
& I_NEW
) {
929 bdev
->bd_contains
= NULL
;
930 bdev
->bd_super
= NULL
;
931 bdev
->bd_inode
= inode
;
932 bdev
->bd_block_size
= i_blocksize(inode
);
933 bdev
->bd_part_count
= 0;
934 bdev
->bd_invalidated
= 0;
935 inode
->i_mode
= S_IFBLK
;
937 inode
->i_bdev
= bdev
;
938 inode
->i_data
.a_ops
= &def_blk_aops
;
939 mapping_set_gfp_mask(&inode
->i_data
, GFP_USER
);
940 spin_lock(&bdev_lock
);
941 list_add(&bdev
->bd_list
, &all_bdevs
);
942 spin_unlock(&bdev_lock
);
943 unlock_new_inode(inode
);
948 EXPORT_SYMBOL(bdget
);
951 * bdgrab -- Grab a reference to an already referenced block device
952 * @bdev: Block device to grab a reference to.
954 struct block_device
*bdgrab(struct block_device
*bdev
)
956 ihold(bdev
->bd_inode
);
959 EXPORT_SYMBOL(bdgrab
);
961 long nr_blockdev_pages(void)
963 struct block_device
*bdev
;
965 spin_lock(&bdev_lock
);
966 list_for_each_entry(bdev
, &all_bdevs
, bd_list
) {
967 ret
+= bdev
->bd_inode
->i_mapping
->nrpages
;
969 spin_unlock(&bdev_lock
);
973 void bdput(struct block_device
*bdev
)
975 iput(bdev
->bd_inode
);
978 EXPORT_SYMBOL(bdput
);
980 static struct block_device
*bd_acquire(struct inode
*inode
)
982 struct block_device
*bdev
;
984 spin_lock(&bdev_lock
);
985 bdev
= inode
->i_bdev
;
986 if (bdev
&& !inode_unhashed(bdev
->bd_inode
)) {
988 spin_unlock(&bdev_lock
);
991 spin_unlock(&bdev_lock
);
994 * i_bdev references block device inode that was already shut down
995 * (corresponding device got removed). Remove the reference and look
996 * up block device inode again just in case new device got
997 * reestablished under the same device number.
1002 bdev
= bdget(inode
->i_rdev
);
1004 spin_lock(&bdev_lock
);
1005 if (!inode
->i_bdev
) {
1007 * We take an additional reference to bd_inode,
1008 * and it's released in clear_inode() of inode.
1009 * So, we can access it via ->i_mapping always
1013 inode
->i_bdev
= bdev
;
1014 inode
->i_mapping
= bdev
->bd_inode
->i_mapping
;
1016 spin_unlock(&bdev_lock
);
1021 /* Call when you free inode */
1023 void bd_forget(struct inode
*inode
)
1025 struct block_device
*bdev
= NULL
;
1027 spin_lock(&bdev_lock
);
1028 if (!sb_is_blkdev_sb(inode
->i_sb
))
1029 bdev
= inode
->i_bdev
;
1030 inode
->i_bdev
= NULL
;
1031 inode
->i_mapping
= &inode
->i_data
;
1032 spin_unlock(&bdev_lock
);
1039 * bd_may_claim - test whether a block device can be claimed
1040 * @bdev: block device of interest
1041 * @whole: whole block device containing @bdev, may equal @bdev
1042 * @holder: holder trying to claim @bdev
1044 * Test whether @bdev can be claimed by @holder.
1047 * spin_lock(&bdev_lock).
1050 * %true if @bdev can be claimed, %false otherwise.
1052 static bool bd_may_claim(struct block_device
*bdev
, struct block_device
*whole
,
1055 if (bdev
->bd_holder
== holder
)
1056 return true; /* already a holder */
1057 else if (bdev
->bd_holder
!= NULL
)
1058 return false; /* held by someone else */
1059 else if (whole
== bdev
)
1060 return true; /* is a whole device which isn't held */
1062 else if (whole
->bd_holder
== bd_may_claim
)
1063 return true; /* is a partition of a device that is being partitioned */
1064 else if (whole
->bd_holder
!= NULL
)
1065 return false; /* is a partition of a held device */
1067 return true; /* is a partition of an un-held device */
1071 * bd_prepare_to_claim - prepare to claim a block device
1072 * @bdev: block device of interest
1073 * @whole: the whole device containing @bdev, may equal @bdev
1074 * @holder: holder trying to claim @bdev
1076 * Prepare to claim @bdev. This function fails if @bdev is already
1077 * claimed by another holder and waits if another claiming is in
1078 * progress. This function doesn't actually claim. On successful
1079 * return, the caller has ownership of bd_claiming and bd_holder[s].
1082 * spin_lock(&bdev_lock). Might release bdev_lock, sleep and regrab
1083 * it multiple times.
1086 * 0 if @bdev can be claimed, -EBUSY otherwise.
1088 static int bd_prepare_to_claim(struct block_device
*bdev
,
1089 struct block_device
*whole
, void *holder
)
1092 /* if someone else claimed, fail */
1093 if (!bd_may_claim(bdev
, whole
, holder
))
1096 /* if claiming is already in progress, wait for it to finish */
1097 if (whole
->bd_claiming
) {
1098 wait_queue_head_t
*wq
= bit_waitqueue(&whole
->bd_claiming
, 0);
1101 prepare_to_wait(wq
, &wait
, TASK_UNINTERRUPTIBLE
);
1102 spin_unlock(&bdev_lock
);
1104 finish_wait(wq
, &wait
);
1105 spin_lock(&bdev_lock
);
1113 static struct gendisk
*bdev_get_gendisk(struct block_device
*bdev
, int *partno
)
1115 struct gendisk
*disk
= get_gendisk(bdev
->bd_dev
, partno
);
1120 * Now that we hold gendisk reference we make sure bdev we looked up is
1121 * not stale. If it is, it means device got removed and created before
1122 * we looked up gendisk and we fail open in such case. Associating
1123 * unhashed bdev with newly created gendisk could lead to two bdevs
1124 * (and thus two independent caches) being associated with one device
1127 if (inode_unhashed(bdev
->bd_inode
)) {
1128 put_disk_and_module(disk
);
1135 * bd_start_claiming - start claiming a block device
1136 * @bdev: block device of interest
1137 * @holder: holder trying to claim @bdev
1139 * @bdev is about to be opened exclusively. Check @bdev can be opened
1140 * exclusively and mark that an exclusive open is in progress. Each
1141 * successful call to this function must be matched with a call to
1142 * either bd_finish_claiming() or bd_abort_claiming() (which do not
1145 * This function is used to gain exclusive access to the block device
1146 * without actually causing other exclusive open attempts to fail. It
1147 * should be used when the open sequence itself requires exclusive
1148 * access but may subsequently fail.
1154 * Pointer to the block device containing @bdev on success, ERR_PTR()
1157 static struct block_device
*bd_start_claiming(struct block_device
*bdev
,
1160 struct gendisk
*disk
;
1161 struct block_device
*whole
;
1167 * @bdev might not have been initialized properly yet, look up
1168 * and grab the outer block device the hard way.
1170 disk
= bdev_get_gendisk(bdev
, &partno
);
1172 return ERR_PTR(-ENXIO
);
1175 * Normally, @bdev should equal what's returned from bdget_disk()
1176 * if partno is 0; however, some drivers (floppy) use multiple
1177 * bdev's for the same physical device and @bdev may be one of the
1178 * aliases. Keep @bdev if partno is 0. This means claimer
1179 * tracking is broken for those devices but it has always been that
1183 whole
= bdget_disk(disk
, 0);
1185 whole
= bdgrab(bdev
);
1187 put_disk_and_module(disk
);
1189 return ERR_PTR(-ENOMEM
);
1191 /* prepare to claim, if successful, mark claiming in progress */
1192 spin_lock(&bdev_lock
);
1194 err
= bd_prepare_to_claim(bdev
, whole
, holder
);
1196 whole
->bd_claiming
= holder
;
1197 spin_unlock(&bdev_lock
);
1200 spin_unlock(&bdev_lock
);
1202 return ERR_PTR(err
);
1207 struct bd_holder_disk
{
1208 struct list_head list
;
1209 struct gendisk
*disk
;
1213 static struct bd_holder_disk
*bd_find_holder_disk(struct block_device
*bdev
,
1214 struct gendisk
*disk
)
1216 struct bd_holder_disk
*holder
;
1218 list_for_each_entry(holder
, &bdev
->bd_holder_disks
, list
)
1219 if (holder
->disk
== disk
)
1224 static int add_symlink(struct kobject
*from
, struct kobject
*to
)
1226 return sysfs_create_link(from
, to
, kobject_name(to
));
1229 static void del_symlink(struct kobject
*from
, struct kobject
*to
)
1231 sysfs_remove_link(from
, kobject_name(to
));
1235 * bd_link_disk_holder - create symlinks between holding disk and slave bdev
1236 * @bdev: the claimed slave bdev
1237 * @disk: the holding disk
1239 * DON'T USE THIS UNLESS YOU'RE ALREADY USING IT.
1241 * This functions creates the following sysfs symlinks.
1243 * - from "slaves" directory of the holder @disk to the claimed @bdev
1244 * - from "holders" directory of the @bdev to the holder @disk
1246 * For example, if /dev/dm-0 maps to /dev/sda and disk for dm-0 is
1247 * passed to bd_link_disk_holder(), then:
1249 * /sys/block/dm-0/slaves/sda --> /sys/block/sda
1250 * /sys/block/sda/holders/dm-0 --> /sys/block/dm-0
1252 * The caller must have claimed @bdev before calling this function and
1253 * ensure that both @bdev and @disk are valid during the creation and
1254 * lifetime of these symlinks.
1260 * 0 on success, -errno on failure.
1262 int bd_link_disk_holder(struct block_device
*bdev
, struct gendisk
*disk
)
1264 struct bd_holder_disk
*holder
;
1267 mutex_lock(&bdev
->bd_mutex
);
1269 WARN_ON_ONCE(!bdev
->bd_holder
);
1271 /* FIXME: remove the following once add_disk() handles errors */
1272 if (WARN_ON(!disk
->slave_dir
|| !bdev
->bd_part
->holder_dir
))
1275 holder
= bd_find_holder_disk(bdev
, disk
);
1281 holder
= kzalloc(sizeof(*holder
), GFP_KERNEL
);
1287 INIT_LIST_HEAD(&holder
->list
);
1288 holder
->disk
= disk
;
1291 ret
= add_symlink(disk
->slave_dir
, &part_to_dev(bdev
->bd_part
)->kobj
);
1295 ret
= add_symlink(bdev
->bd_part
->holder_dir
, &disk_to_dev(disk
)->kobj
);
1299 * bdev could be deleted beneath us which would implicitly destroy
1300 * the holder directory. Hold on to it.
1302 kobject_get(bdev
->bd_part
->holder_dir
);
1304 list_add(&holder
->list
, &bdev
->bd_holder_disks
);
1308 del_symlink(disk
->slave_dir
, &part_to_dev(bdev
->bd_part
)->kobj
);
1312 mutex_unlock(&bdev
->bd_mutex
);
1315 EXPORT_SYMBOL_GPL(bd_link_disk_holder
);
1318 * bd_unlink_disk_holder - destroy symlinks created by bd_link_disk_holder()
1319 * @bdev: the calimed slave bdev
1320 * @disk: the holding disk
1322 * DON'T USE THIS UNLESS YOU'RE ALREADY USING IT.
1327 void bd_unlink_disk_holder(struct block_device
*bdev
, struct gendisk
*disk
)
1329 struct bd_holder_disk
*holder
;
1331 mutex_lock(&bdev
->bd_mutex
);
1333 holder
= bd_find_holder_disk(bdev
, disk
);
1335 if (!WARN_ON_ONCE(holder
== NULL
) && !--holder
->refcnt
) {
1336 del_symlink(disk
->slave_dir
, &part_to_dev(bdev
->bd_part
)->kobj
);
1337 del_symlink(bdev
->bd_part
->holder_dir
,
1338 &disk_to_dev(disk
)->kobj
);
1339 kobject_put(bdev
->bd_part
->holder_dir
);
1340 list_del_init(&holder
->list
);
1344 mutex_unlock(&bdev
->bd_mutex
);
1346 EXPORT_SYMBOL_GPL(bd_unlink_disk_holder
);
1350 * flush_disk - invalidates all buffer-cache entries on a disk
1352 * @bdev: struct block device to be flushed
1353 * @kill_dirty: flag to guide handling of dirty inodes
1355 * Invalidates all buffer-cache entries on a disk. It should be called
1356 * when a disk has been changed -- either by a media change or online
1359 static void flush_disk(struct block_device
*bdev
, bool kill_dirty
)
1361 if (__invalidate_device(bdev
, kill_dirty
)) {
1362 printk(KERN_WARNING
"VFS: busy inodes on changed media or "
1363 "resized disk %s\n",
1364 bdev
->bd_disk
? bdev
->bd_disk
->disk_name
: "");
1369 if (disk_part_scan_enabled(bdev
->bd_disk
))
1370 bdev
->bd_invalidated
= 1;
1374 * check_disk_size_change - checks for disk size change and adjusts bdev size.
1375 * @disk: struct gendisk to check
1376 * @bdev: struct bdev to adjust.
1377 * @verbose: if %true log a message about a size change if there is any
1379 * This routine checks to see if the bdev size does not match the disk size
1380 * and adjusts it if it differs. When shrinking the bdev size, its all caches
1383 void check_disk_size_change(struct gendisk
*disk
, struct block_device
*bdev
,
1386 loff_t disk_size
, bdev_size
;
1388 disk_size
= (loff_t
)get_capacity(disk
) << 9;
1389 bdev_size
= i_size_read(bdev
->bd_inode
);
1390 if (disk_size
!= bdev_size
) {
1393 "%s: detected capacity change from %lld to %lld\n",
1394 disk
->disk_name
, bdev_size
, disk_size
);
1396 i_size_write(bdev
->bd_inode
, disk_size
);
1397 if (bdev_size
> disk_size
)
1398 flush_disk(bdev
, false);
1403 * revalidate_disk - wrapper for lower-level driver's revalidate_disk call-back
1404 * @disk: struct gendisk to be revalidated
1406 * This routine is a wrapper for lower-level driver's revalidate_disk
1407 * call-backs. It is used to do common pre and post operations needed
1408 * for all revalidate_disk operations.
1410 int revalidate_disk(struct gendisk
*disk
)
1412 struct block_device
*bdev
;
1415 if (disk
->fops
->revalidate_disk
)
1416 ret
= disk
->fops
->revalidate_disk(disk
);
1417 bdev
= bdget_disk(disk
, 0);
1421 mutex_lock(&bdev
->bd_mutex
);
1422 check_disk_size_change(disk
, bdev
, ret
== 0);
1423 bdev
->bd_invalidated
= 0;
1424 mutex_unlock(&bdev
->bd_mutex
);
1428 EXPORT_SYMBOL(revalidate_disk
);
1431 * This routine checks whether a removable media has been changed,
1432 * and invalidates all buffer-cache-entries in that case. This
1433 * is a relatively slow routine, so we have to try to minimize using
1434 * it. Thus it is called only upon a 'mount' or 'open'. This
1435 * is the best way of combining speed and utility, I think.
1436 * People changing diskettes in the middle of an operation deserve
1439 int check_disk_change(struct block_device
*bdev
)
1441 struct gendisk
*disk
= bdev
->bd_disk
;
1442 const struct block_device_operations
*bdops
= disk
->fops
;
1443 unsigned int events
;
1445 events
= disk_clear_events(disk
, DISK_EVENT_MEDIA_CHANGE
|
1446 DISK_EVENT_EJECT_REQUEST
);
1447 if (!(events
& DISK_EVENT_MEDIA_CHANGE
))
1450 flush_disk(bdev
, true);
1451 if (bdops
->revalidate_disk
)
1452 bdops
->revalidate_disk(bdev
->bd_disk
);
1456 EXPORT_SYMBOL(check_disk_change
);
1458 void bd_set_size(struct block_device
*bdev
, loff_t size
)
1460 inode_lock(bdev
->bd_inode
);
1461 i_size_write(bdev
->bd_inode
, size
);
1462 inode_unlock(bdev
->bd_inode
);
1464 EXPORT_SYMBOL(bd_set_size
);
1466 static void __blkdev_put(struct block_device
*bdev
, fmode_t mode
, int for_part
);
1471 * mutex_lock(part->bd_mutex)
1472 * mutex_lock_nested(whole->bd_mutex, 1)
1475 static int __blkdev_get(struct block_device
*bdev
, fmode_t mode
, int for_part
)
1477 struct gendisk
*disk
;
1481 bool first_open
= false;
1483 if (mode
& FMODE_READ
)
1485 if (mode
& FMODE_WRITE
)
1488 * hooks: /n/, see "layering violations".
1491 ret
= devcgroup_inode_permission(bdev
->bd_inode
, perm
);
1501 disk
= bdev_get_gendisk(bdev
, &partno
);
1505 disk_block_events(disk
);
1506 mutex_lock_nested(&bdev
->bd_mutex
, for_part
);
1507 if (!bdev
->bd_openers
) {
1509 bdev
->bd_disk
= disk
;
1510 bdev
->bd_queue
= disk
->queue
;
1511 bdev
->bd_contains
= bdev
;
1512 bdev
->bd_partno
= partno
;
1516 bdev
->bd_part
= disk_get_part(disk
, partno
);
1521 if (disk
->fops
->open
) {
1522 ret
= disk
->fops
->open(bdev
, mode
);
1523 if (ret
== -ERESTARTSYS
) {
1524 /* Lost a race with 'disk' being
1525 * deleted, try again.
1528 disk_put_part(bdev
->bd_part
);
1529 bdev
->bd_part
= NULL
;
1530 bdev
->bd_disk
= NULL
;
1531 bdev
->bd_queue
= NULL
;
1532 mutex_unlock(&bdev
->bd_mutex
);
1533 disk_unblock_events(disk
);
1534 put_disk_and_module(disk
);
1540 bd_set_size(bdev
,(loff_t
)get_capacity(disk
)<<9);
1541 set_init_blocksize(bdev
);
1545 * If the device is invalidated, rescan partition
1546 * if open succeeded or failed with -ENOMEDIUM.
1547 * The latter is necessary to prevent ghost
1548 * partitions on a removed medium.
1550 if (bdev
->bd_invalidated
) {
1552 rescan_partitions(disk
, bdev
);
1553 else if (ret
== -ENOMEDIUM
)
1554 invalidate_partitions(disk
, bdev
);
1560 struct block_device
*whole
;
1561 whole
= bdget_disk(disk
, 0);
1566 ret
= __blkdev_get(whole
, mode
, 1);
1569 bdev
->bd_contains
= whole
;
1570 bdev
->bd_part
= disk_get_part(disk
, partno
);
1571 if (!(disk
->flags
& GENHD_FL_UP
) ||
1572 !bdev
->bd_part
|| !bdev
->bd_part
->nr_sects
) {
1576 bd_set_size(bdev
, (loff_t
)bdev
->bd_part
->nr_sects
<< 9);
1577 set_init_blocksize(bdev
);
1580 if (bdev
->bd_bdi
== &noop_backing_dev_info
)
1581 bdev
->bd_bdi
= bdi_get(disk
->queue
->backing_dev_info
);
1583 if (bdev
->bd_contains
== bdev
) {
1585 if (bdev
->bd_disk
->fops
->open
)
1586 ret
= bdev
->bd_disk
->fops
->open(bdev
, mode
);
1587 /* the same as first opener case, read comment there */
1588 if (bdev
->bd_invalidated
) {
1590 rescan_partitions(bdev
->bd_disk
, bdev
);
1591 else if (ret
== -ENOMEDIUM
)
1592 invalidate_partitions(bdev
->bd_disk
, bdev
);
1595 goto out_unlock_bdev
;
1600 bdev
->bd_part_count
++;
1601 mutex_unlock(&bdev
->bd_mutex
);
1602 disk_unblock_events(disk
);
1603 /* only one opener holds refs to the module and disk */
1605 put_disk_and_module(disk
);
1609 disk_put_part(bdev
->bd_part
);
1610 bdev
->bd_disk
= NULL
;
1611 bdev
->bd_part
= NULL
;
1612 bdev
->bd_queue
= NULL
;
1613 if (bdev
!= bdev
->bd_contains
)
1614 __blkdev_put(bdev
->bd_contains
, mode
, 1);
1615 bdev
->bd_contains
= NULL
;
1617 mutex_unlock(&bdev
->bd_mutex
);
1618 disk_unblock_events(disk
);
1619 put_disk_and_module(disk
);
1627 * blkdev_get - open a block device
1628 * @bdev: block_device to open
1629 * @mode: FMODE_* mask
1630 * @holder: exclusive holder identifier
1632 * Open @bdev with @mode. If @mode includes %FMODE_EXCL, @bdev is
1633 * open with exclusive access. Specifying %FMODE_EXCL with %NULL
1634 * @holder is invalid. Exclusive opens may nest for the same @holder.
1636 * On success, the reference count of @bdev is unchanged. On failure,
1643 * 0 on success, -errno on failure.
1645 int blkdev_get(struct block_device
*bdev
, fmode_t mode
, void *holder
)
1647 struct block_device
*whole
= NULL
;
1650 WARN_ON_ONCE((mode
& FMODE_EXCL
) && !holder
);
1652 if ((mode
& FMODE_EXCL
) && holder
) {
1653 whole
= bd_start_claiming(bdev
, holder
);
1654 if (IS_ERR(whole
)) {
1656 return PTR_ERR(whole
);
1660 res
= __blkdev_get(bdev
, mode
, 0);
1663 struct gendisk
*disk
= whole
->bd_disk
;
1665 /* finish claiming */
1666 mutex_lock(&bdev
->bd_mutex
);
1667 spin_lock(&bdev_lock
);
1670 BUG_ON(!bd_may_claim(bdev
, whole
, holder
));
1672 * Note that for a whole device bd_holders
1673 * will be incremented twice, and bd_holder
1674 * will be set to bd_may_claim before being
1677 whole
->bd_holders
++;
1678 whole
->bd_holder
= bd_may_claim
;
1680 bdev
->bd_holder
= holder
;
1683 /* tell others that we're done */
1684 BUG_ON(whole
->bd_claiming
!= holder
);
1685 whole
->bd_claiming
= NULL
;
1686 wake_up_bit(&whole
->bd_claiming
, 0);
1688 spin_unlock(&bdev_lock
);
1691 * Block event polling for write claims if requested. Any
1692 * write holder makes the write_holder state stick until
1693 * all are released. This is good enough and tracking
1694 * individual writeable reference is too fragile given the
1695 * way @mode is used in blkdev_get/put().
1697 if (!res
&& (mode
& FMODE_WRITE
) && !bdev
->bd_write_holder
&&
1698 (disk
->flags
& GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE
)) {
1699 bdev
->bd_write_holder
= true;
1700 disk_block_events(disk
);
1703 mutex_unlock(&bdev
->bd_mutex
);
1709 EXPORT_SYMBOL(blkdev_get
);
1712 * blkdev_get_by_path - open a block device by name
1713 * @path: path to the block device to open
1714 * @mode: FMODE_* mask
1715 * @holder: exclusive holder identifier
1717 * Open the blockdevice described by the device file at @path. @mode
1718 * and @holder are identical to blkdev_get().
1720 * On success, the returned block_device has reference count of one.
1726 * Pointer to block_device on success, ERR_PTR(-errno) on failure.
1728 struct block_device
*blkdev_get_by_path(const char *path
, fmode_t mode
,
1731 struct block_device
*bdev
;
1734 bdev
= lookup_bdev(path
);
1738 err
= blkdev_get(bdev
, mode
, holder
);
1740 return ERR_PTR(err
);
1742 if ((mode
& FMODE_WRITE
) && bdev_read_only(bdev
)) {
1743 blkdev_put(bdev
, mode
);
1744 return ERR_PTR(-EACCES
);
1749 EXPORT_SYMBOL(blkdev_get_by_path
);
1752 * blkdev_get_by_dev - open a block device by device number
1753 * @dev: device number of block device to open
1754 * @mode: FMODE_* mask
1755 * @holder: exclusive holder identifier
1757 * Open the blockdevice described by device number @dev. @mode and
1758 * @holder are identical to blkdev_get().
1760 * Use it ONLY if you really do not have anything better - i.e. when
1761 * you are behind a truly sucky interface and all you are given is a
1762 * device number. _Never_ to be used for internal purposes. If you
1763 * ever need it - reconsider your API.
1765 * On success, the returned block_device has reference count of one.
1771 * Pointer to block_device on success, ERR_PTR(-errno) on failure.
1773 struct block_device
*blkdev_get_by_dev(dev_t dev
, fmode_t mode
, void *holder
)
1775 struct block_device
*bdev
;
1780 return ERR_PTR(-ENOMEM
);
1782 err
= blkdev_get(bdev
, mode
, holder
);
1784 return ERR_PTR(err
);
1788 EXPORT_SYMBOL(blkdev_get_by_dev
);
1790 static int blkdev_open(struct inode
* inode
, struct file
* filp
)
1792 struct block_device
*bdev
;
1795 * Preserve backwards compatibility and allow large file access
1796 * even if userspace doesn't ask for it explicitly. Some mkfs
1797 * binary needs it. We might want to drop this workaround
1798 * during an unstable branch.
1800 filp
->f_flags
|= O_LARGEFILE
;
1802 filp
->f_mode
|= FMODE_NOWAIT
;
1804 if (filp
->f_flags
& O_NDELAY
)
1805 filp
->f_mode
|= FMODE_NDELAY
;
1806 if (filp
->f_flags
& O_EXCL
)
1807 filp
->f_mode
|= FMODE_EXCL
;
1808 if ((filp
->f_flags
& O_ACCMODE
) == 3)
1809 filp
->f_mode
|= FMODE_WRITE_IOCTL
;
1811 bdev
= bd_acquire(inode
);
1815 filp
->f_mapping
= bdev
->bd_inode
->i_mapping
;
1816 filp
->f_wb_err
= filemap_sample_wb_err(filp
->f_mapping
);
1818 return blkdev_get(bdev
, filp
->f_mode
, filp
);
1821 static void __blkdev_put(struct block_device
*bdev
, fmode_t mode
, int for_part
)
1823 struct gendisk
*disk
= bdev
->bd_disk
;
1824 struct block_device
*victim
= NULL
;
1826 mutex_lock_nested(&bdev
->bd_mutex
, for_part
);
1828 bdev
->bd_part_count
--;
1830 if (!--bdev
->bd_openers
) {
1831 WARN_ON_ONCE(bdev
->bd_holders
);
1832 sync_blockdev(bdev
);
1835 bdev_write_inode(bdev
);
1837 if (bdev
->bd_contains
== bdev
) {
1838 if (disk
->fops
->release
)
1839 disk
->fops
->release(disk
, mode
);
1841 if (!bdev
->bd_openers
) {
1842 disk_put_part(bdev
->bd_part
);
1843 bdev
->bd_part
= NULL
;
1844 bdev
->bd_disk
= NULL
;
1845 if (bdev
!= bdev
->bd_contains
)
1846 victim
= bdev
->bd_contains
;
1847 bdev
->bd_contains
= NULL
;
1849 put_disk_and_module(disk
);
1851 mutex_unlock(&bdev
->bd_mutex
);
1854 __blkdev_put(victim
, mode
, 1);
1857 void blkdev_put(struct block_device
*bdev
, fmode_t mode
)
1859 mutex_lock(&bdev
->bd_mutex
);
1861 if (mode
& FMODE_EXCL
) {
1865 * Release a claim on the device. The holder fields
1866 * are protected with bdev_lock. bd_mutex is to
1867 * synchronize disk_holder unlinking.
1869 spin_lock(&bdev_lock
);
1871 WARN_ON_ONCE(--bdev
->bd_holders
< 0);
1872 WARN_ON_ONCE(--bdev
->bd_contains
->bd_holders
< 0);
1874 /* bd_contains might point to self, check in a separate step */
1875 if ((bdev_free
= !bdev
->bd_holders
))
1876 bdev
->bd_holder
= NULL
;
1877 if (!bdev
->bd_contains
->bd_holders
)
1878 bdev
->bd_contains
->bd_holder
= NULL
;
1880 spin_unlock(&bdev_lock
);
1883 * If this was the last claim, remove holder link and
1884 * unblock evpoll if it was a write holder.
1886 if (bdev_free
&& bdev
->bd_write_holder
) {
1887 disk_unblock_events(bdev
->bd_disk
);
1888 bdev
->bd_write_holder
= false;
1893 * Trigger event checking and tell drivers to flush MEDIA_CHANGE
1894 * event. This is to ensure detection of media removal commanded
1895 * from userland - e.g. eject(1).
1897 disk_flush_events(bdev
->bd_disk
, DISK_EVENT_MEDIA_CHANGE
);
1899 mutex_unlock(&bdev
->bd_mutex
);
1901 __blkdev_put(bdev
, mode
, 0);
1903 EXPORT_SYMBOL(blkdev_put
);
1905 static int blkdev_close(struct inode
* inode
, struct file
* filp
)
1907 struct block_device
*bdev
= I_BDEV(bdev_file_inode(filp
));
1908 blkdev_put(bdev
, filp
->f_mode
);
1912 static long block_ioctl(struct file
*file
, unsigned cmd
, unsigned long arg
)
1914 struct block_device
*bdev
= I_BDEV(bdev_file_inode(file
));
1915 fmode_t mode
= file
->f_mode
;
1918 * O_NDELAY can be altered using fcntl(.., F_SETFL, ..), so we have
1919 * to updated it before every ioctl.
1921 if (file
->f_flags
& O_NDELAY
)
1922 mode
|= FMODE_NDELAY
;
1924 mode
&= ~FMODE_NDELAY
;
1926 return blkdev_ioctl(bdev
, mode
, cmd
, arg
);
1930 * Write data to the block device. Only intended for the block device itself
1931 * and the raw driver which basically is a fake block device.
1933 * Does not take i_mutex for the write and thus is not for general purpose
1936 ssize_t
blkdev_write_iter(struct kiocb
*iocb
, struct iov_iter
*from
)
1938 struct file
*file
= iocb
->ki_filp
;
1939 struct inode
*bd_inode
= bdev_file_inode(file
);
1940 loff_t size
= i_size_read(bd_inode
);
1941 struct blk_plug plug
;
1944 if (bdev_read_only(I_BDEV(bd_inode
)))
1947 if (!iov_iter_count(from
))
1950 if (iocb
->ki_pos
>= size
)
1953 if ((iocb
->ki_flags
& (IOCB_NOWAIT
| IOCB_DIRECT
)) == IOCB_NOWAIT
)
1956 iov_iter_truncate(from
, size
- iocb
->ki_pos
);
1958 blk_start_plug(&plug
);
1959 ret
= __generic_file_write_iter(iocb
, from
);
1961 ret
= generic_write_sync(iocb
, ret
);
1962 blk_finish_plug(&plug
);
1965 EXPORT_SYMBOL_GPL(blkdev_write_iter
);
1967 ssize_t
blkdev_read_iter(struct kiocb
*iocb
, struct iov_iter
*to
)
1969 struct file
*file
= iocb
->ki_filp
;
1970 struct inode
*bd_inode
= bdev_file_inode(file
);
1971 loff_t size
= i_size_read(bd_inode
);
1972 loff_t pos
= iocb
->ki_pos
;
1978 iov_iter_truncate(to
, size
);
1979 return generic_file_read_iter(iocb
, to
);
1981 EXPORT_SYMBOL_GPL(blkdev_read_iter
);
1984 * Try to release a page associated with block device when the system
1985 * is under memory pressure.
1987 static int blkdev_releasepage(struct page
*page
, gfp_t wait
)
1989 struct super_block
*super
= BDEV_I(page
->mapping
->host
)->bdev
.bd_super
;
1991 if (super
&& super
->s_op
->bdev_try_to_free_page
)
1992 return super
->s_op
->bdev_try_to_free_page(super
, page
, wait
);
1994 return try_to_free_buffers(page
);
1997 static int blkdev_writepages(struct address_space
*mapping
,
1998 struct writeback_control
*wbc
)
2000 return generic_writepages(mapping
, wbc
);
2003 static const struct address_space_operations def_blk_aops
= {
2004 .readpage
= blkdev_readpage
,
2005 .readpages
= blkdev_readpages
,
2006 .writepage
= blkdev_writepage
,
2007 .write_begin
= blkdev_write_begin
,
2008 .write_end
= blkdev_write_end
,
2009 .writepages
= blkdev_writepages
,
2010 .releasepage
= blkdev_releasepage
,
2011 .direct_IO
= blkdev_direct_IO
,
2012 .migratepage
= buffer_migrate_page_norefs
,
2013 .is_dirty_writeback
= buffer_check_dirty_writeback
,
2016 #define BLKDEV_FALLOC_FL_SUPPORTED \
2017 (FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE | \
2018 FALLOC_FL_ZERO_RANGE | FALLOC_FL_NO_HIDE_STALE)
2020 static long blkdev_fallocate(struct file
*file
, int mode
, loff_t start
,
2023 struct block_device
*bdev
= I_BDEV(bdev_file_inode(file
));
2024 struct address_space
*mapping
;
2025 loff_t end
= start
+ len
- 1;
2029 /* Fail if we don't recognize the flags. */
2030 if (mode
& ~BLKDEV_FALLOC_FL_SUPPORTED
)
2033 /* Don't go off the end of the device. */
2034 isize
= i_size_read(bdev
->bd_inode
);
2038 if (mode
& FALLOC_FL_KEEP_SIZE
) {
2039 len
= isize
- start
;
2040 end
= start
+ len
- 1;
2046 * Don't allow IO that isn't aligned to logical block size.
2048 if ((start
| len
) & (bdev_logical_block_size(bdev
) - 1))
2051 /* Invalidate the page cache, including dirty pages. */
2052 mapping
= bdev
->bd_inode
->i_mapping
;
2053 truncate_inode_pages_range(mapping
, start
, end
);
2056 case FALLOC_FL_ZERO_RANGE
:
2057 case FALLOC_FL_ZERO_RANGE
| FALLOC_FL_KEEP_SIZE
:
2058 error
= blkdev_issue_zeroout(bdev
, start
>> 9, len
>> 9,
2059 GFP_KERNEL
, BLKDEV_ZERO_NOUNMAP
);
2061 case FALLOC_FL_PUNCH_HOLE
| FALLOC_FL_KEEP_SIZE
:
2062 error
= blkdev_issue_zeroout(bdev
, start
>> 9, len
>> 9,
2063 GFP_KERNEL
, BLKDEV_ZERO_NOFALLBACK
);
2065 case FALLOC_FL_PUNCH_HOLE
| FALLOC_FL_KEEP_SIZE
| FALLOC_FL_NO_HIDE_STALE
:
2066 error
= blkdev_issue_discard(bdev
, start
>> 9, len
>> 9,
2076 * Invalidate again; if someone wandered in and dirtied a page,
2077 * the caller will be given -EBUSY. The third argument is
2078 * inclusive, so the rounding here is safe.
2080 return invalidate_inode_pages2_range(mapping
,
2081 start
>> PAGE_SHIFT
,
2085 const struct file_operations def_blk_fops
= {
2086 .open
= blkdev_open
,
2087 .release
= blkdev_close
,
2088 .llseek
= block_llseek
,
2089 .read_iter
= blkdev_read_iter
,
2090 .write_iter
= blkdev_write_iter
,
2091 .iopoll
= blkdev_iopoll
,
2092 .mmap
= generic_file_mmap
,
2093 .fsync
= blkdev_fsync
,
2094 .unlocked_ioctl
= block_ioctl
,
2095 #ifdef CONFIG_COMPAT
2096 .compat_ioctl
= compat_blkdev_ioctl
,
2098 .splice_read
= generic_file_splice_read
,
2099 .splice_write
= iter_file_splice_write
,
2100 .fallocate
= blkdev_fallocate
,
2103 int ioctl_by_bdev(struct block_device
*bdev
, unsigned cmd
, unsigned long arg
)
2106 mm_segment_t old_fs
= get_fs();
2108 res
= blkdev_ioctl(bdev
, 0, cmd
, arg
);
2113 EXPORT_SYMBOL(ioctl_by_bdev
);
2116 * lookup_bdev - lookup a struct block_device by name
2117 * @pathname: special file representing the block device
2119 * Get a reference to the blockdevice at @pathname in the current
2120 * namespace if possible and return it. Return ERR_PTR(error)
2123 struct block_device
*lookup_bdev(const char *pathname
)
2125 struct block_device
*bdev
;
2126 struct inode
*inode
;
2130 if (!pathname
|| !*pathname
)
2131 return ERR_PTR(-EINVAL
);
2133 error
= kern_path(pathname
, LOOKUP_FOLLOW
, &path
);
2135 return ERR_PTR(error
);
2137 inode
= d_backing_inode(path
.dentry
);
2139 if (!S_ISBLK(inode
->i_mode
))
2142 if (!may_open_dev(&path
))
2145 bdev
= bd_acquire(inode
);
2152 bdev
= ERR_PTR(error
);
2155 EXPORT_SYMBOL(lookup_bdev
);
2157 int __invalidate_device(struct block_device
*bdev
, bool kill_dirty
)
2159 struct super_block
*sb
= get_super(bdev
);
2164 * no need to lock the super, get_super holds the
2165 * read mutex so the filesystem cannot go away
2166 * under us (->put_super runs with the write lock
2169 shrink_dcache_sb(sb
);
2170 res
= invalidate_inodes(sb
, kill_dirty
);
2173 invalidate_bdev(bdev
);
2176 EXPORT_SYMBOL(__invalidate_device
);
2178 void iterate_bdevs(void (*func
)(struct block_device
*, void *), void *arg
)
2180 struct inode
*inode
, *old_inode
= NULL
;
2182 spin_lock(&blockdev_superblock
->s_inode_list_lock
);
2183 list_for_each_entry(inode
, &blockdev_superblock
->s_inodes
, i_sb_list
) {
2184 struct address_space
*mapping
= inode
->i_mapping
;
2185 struct block_device
*bdev
;
2187 spin_lock(&inode
->i_lock
);
2188 if (inode
->i_state
& (I_FREEING
|I_WILL_FREE
|I_NEW
) ||
2189 mapping
->nrpages
== 0) {
2190 spin_unlock(&inode
->i_lock
);
2194 spin_unlock(&inode
->i_lock
);
2195 spin_unlock(&blockdev_superblock
->s_inode_list_lock
);
2197 * We hold a reference to 'inode' so it couldn't have been
2198 * removed from s_inodes list while we dropped the
2199 * s_inode_list_lock We cannot iput the inode now as we can
2200 * be holding the last reference and we cannot iput it under
2201 * s_inode_list_lock. So we keep the reference and iput it
2206 bdev
= I_BDEV(inode
);
2208 mutex_lock(&bdev
->bd_mutex
);
2209 if (bdev
->bd_openers
)
2211 mutex_unlock(&bdev
->bd_mutex
);
2213 spin_lock(&blockdev_superblock
->s_inode_list_lock
);
2215 spin_unlock(&blockdev_superblock
->s_inode_list_lock
);