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 void __vfs_msg(struct super_block
*sb
, const char *prefix
, const char *fmt
, ...)
65 printk_ratelimited("%sVFS (%s): %pV\n", prefix
, sb
->s_id
, &vaf
);
69 static void bdev_write_inode(struct block_device
*bdev
)
71 struct inode
*inode
= bdev
->bd_inode
;
74 spin_lock(&inode
->i_lock
);
75 while (inode
->i_state
& I_DIRTY
) {
76 spin_unlock(&inode
->i_lock
);
77 ret
= write_inode_now(inode
, true);
79 char name
[BDEVNAME_SIZE
];
80 pr_warn_ratelimited("VFS: Dirty inode writeback failed "
81 "for block device %s (err=%d).\n",
82 bdevname(bdev
, name
), ret
);
84 spin_lock(&inode
->i_lock
);
86 spin_unlock(&inode
->i_lock
);
89 /* Kill _all_ buffers and pagecache , dirty or not.. */
90 void kill_bdev(struct block_device
*bdev
)
92 struct address_space
*mapping
= bdev
->bd_inode
->i_mapping
;
94 if (mapping
->nrpages
== 0 && mapping
->nrexceptional
== 0)
98 truncate_inode_pages(mapping
, 0);
100 EXPORT_SYMBOL(kill_bdev
);
102 /* Invalidate clean unused buffers and pagecache. */
103 void invalidate_bdev(struct block_device
*bdev
)
105 struct address_space
*mapping
= bdev
->bd_inode
->i_mapping
;
107 if (mapping
->nrpages
) {
108 invalidate_bh_lrus();
109 lru_add_drain_all(); /* make sure all lru add caches are flushed */
110 invalidate_mapping_pages(mapping
, 0, -1);
112 /* 99% of the time, we don't need to flush the cleancache on the bdev.
113 * But, for the strange corners, lets be cautious
115 cleancache_invalidate_inode(mapping
);
117 EXPORT_SYMBOL(invalidate_bdev
);
119 int set_blocksize(struct block_device
*bdev
, int size
)
121 /* Size must be a power of two, and between 512 and PAGE_SIZE */
122 if (size
> PAGE_SIZE
|| size
< 512 || !is_power_of_2(size
))
125 /* Size cannot be smaller than the size supported by the device */
126 if (size
< bdev_logical_block_size(bdev
))
129 /* Don't change the size if it is same as current */
130 if (bdev
->bd_block_size
!= size
) {
132 bdev
->bd_block_size
= size
;
133 bdev
->bd_inode
->i_blkbits
= blksize_bits(size
);
139 EXPORT_SYMBOL(set_blocksize
);
141 int sb_set_blocksize(struct super_block
*sb
, int size
)
143 if (set_blocksize(sb
->s_bdev
, size
))
145 /* If we get here, we know size is power of two
146 * and it's value is between 512 and PAGE_SIZE */
147 sb
->s_blocksize
= size
;
148 sb
->s_blocksize_bits
= blksize_bits(size
);
149 return sb
->s_blocksize
;
152 EXPORT_SYMBOL(sb_set_blocksize
);
154 int sb_min_blocksize(struct super_block
*sb
, int size
)
156 int minsize
= bdev_logical_block_size(sb
->s_bdev
);
159 return sb_set_blocksize(sb
, size
);
162 EXPORT_SYMBOL(sb_min_blocksize
);
165 blkdev_get_block(struct inode
*inode
, sector_t iblock
,
166 struct buffer_head
*bh
, int create
)
168 bh
->b_bdev
= I_BDEV(inode
);
169 bh
->b_blocknr
= iblock
;
170 set_buffer_mapped(bh
);
174 static struct inode
*bdev_file_inode(struct file
*file
)
176 return file
->f_mapping
->host
;
179 static unsigned int dio_bio_write_op(struct kiocb
*iocb
)
181 unsigned int op
= REQ_OP_WRITE
| REQ_SYNC
| REQ_IDLE
;
183 /* avoid the need for a I/O completion work item */
184 if (iocb
->ki_flags
& IOCB_DSYNC
)
189 #define DIO_INLINE_BIO_VECS 4
191 static void blkdev_bio_end_io_simple(struct bio
*bio
)
193 struct task_struct
*waiter
= bio
->bi_private
;
195 WRITE_ONCE(bio
->bi_private
, NULL
);
196 wake_up_process(waiter
);
200 __blkdev_direct_IO_simple(struct kiocb
*iocb
, struct iov_iter
*iter
,
203 struct file
*file
= iocb
->ki_filp
;
204 struct block_device
*bdev
= I_BDEV(bdev_file_inode(file
));
205 struct bio_vec inline_vecs
[DIO_INLINE_BIO_VECS
], *vecs
, *bvec
;
206 loff_t pos
= iocb
->ki_pos
;
207 bool should_dirty
= false;
213 if ((pos
| iov_iter_alignment(iter
)) &
214 (bdev_logical_block_size(bdev
) - 1))
217 if (nr_pages
<= DIO_INLINE_BIO_VECS
)
220 vecs
= kmalloc(nr_pages
* sizeof(struct bio_vec
), GFP_KERNEL
);
225 bio_init(&bio
, vecs
, nr_pages
);
227 bio
.bi_iter
.bi_sector
= pos
>> 9;
228 bio
.bi_private
= current
;
229 bio
.bi_end_io
= blkdev_bio_end_io_simple
;
231 ret
= bio_iov_iter_get_pages(&bio
, iter
);
234 ret
= bio
.bi_iter
.bi_size
;
236 if (iov_iter_rw(iter
) == READ
) {
237 bio
.bi_opf
= REQ_OP_READ
;
238 if (iter_is_iovec(iter
))
241 bio
.bi_opf
= dio_bio_write_op(iocb
);
242 task_io_account_write(ret
);
245 qc
= submit_bio(&bio
);
247 set_current_state(TASK_UNINTERRUPTIBLE
);
248 if (!READ_ONCE(bio
.bi_private
))
250 if (!(iocb
->ki_flags
& IOCB_HIPRI
) ||
251 !blk_mq_poll(bdev_get_queue(bdev
), qc
))
254 __set_current_state(TASK_RUNNING
);
256 bio_for_each_segment_all(bvec
, &bio
, i
) {
257 if (should_dirty
&& !PageCompound(bvec
->bv_page
))
258 set_page_dirty_lock(bvec
->bv_page
);
259 put_page(bvec
->bv_page
);
262 if (vecs
!= inline_vecs
)
265 if (unlikely(bio
.bi_error
))
273 struct task_struct
*waiter
;
278 bool should_dirty
: 1;
283 static struct bio_set
*blkdev_dio_pool __read_mostly
;
285 static void blkdev_bio_end_io(struct bio
*bio
)
287 struct blkdev_dio
*dio
= bio
->bi_private
;
288 bool should_dirty
= dio
->should_dirty
;
290 if (dio
->multi_bio
&& !atomic_dec_and_test(&dio
->ref
)) {
291 if (bio
->bi_error
&& !dio
->bio
.bi_error
)
292 dio
->bio
.bi_error
= bio
->bi_error
;
295 struct kiocb
*iocb
= dio
->iocb
;
296 ssize_t ret
= dio
->bio
.bi_error
;
303 dio
->iocb
->ki_complete(iocb
, ret
, 0);
306 struct task_struct
*waiter
= dio
->waiter
;
308 WRITE_ONCE(dio
->waiter
, NULL
);
309 wake_up_process(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_read
= (iov_iter_rw(iter
) == READ
), is_sync
;
335 loff_t pos
= iocb
->ki_pos
;
336 blk_qc_t qc
= BLK_QC_T_NONE
;
339 if ((pos
| iov_iter_alignment(iter
)) &
340 (bdev_logical_block_size(bdev
) - 1))
343 bio
= bio_alloc_bioset(GFP_KERNEL
, nr_pages
, blkdev_dio_pool
);
344 bio_get(bio
); /* extra ref for the completion handler */
346 dio
= container_of(bio
, struct blkdev_dio
, bio
);
347 dio
->is_sync
= is_sync
= is_sync_kiocb(iocb
);
349 dio
->waiter
= current
;
354 dio
->multi_bio
= false;
355 dio
->should_dirty
= is_read
&& (iter
->type
== ITER_IOVEC
);
357 blk_start_plug(&plug
);
360 bio
->bi_iter
.bi_sector
= pos
>> 9;
361 bio
->bi_private
= dio
;
362 bio
->bi_end_io
= blkdev_bio_end_io
;
364 ret
= bio_iov_iter_get_pages(bio
, iter
);
372 bio
->bi_opf
= REQ_OP_READ
;
373 if (dio
->should_dirty
)
374 bio_set_pages_dirty(bio
);
376 bio
->bi_opf
= dio_bio_write_op(iocb
);
377 task_io_account_write(bio
->bi_iter
.bi_size
);
380 dio
->size
+= bio
->bi_iter
.bi_size
;
381 pos
+= bio
->bi_iter
.bi_size
;
383 nr_pages
= iov_iter_npages(iter
, BIO_MAX_PAGES
);
385 qc
= submit_bio(bio
);
389 if (!dio
->multi_bio
) {
390 dio
->multi_bio
= true;
391 atomic_set(&dio
->ref
, 2);
393 atomic_inc(&dio
->ref
);
397 bio
= bio_alloc(GFP_KERNEL
, nr_pages
);
399 blk_finish_plug(&plug
);
405 set_current_state(TASK_UNINTERRUPTIBLE
);
406 if (!READ_ONCE(dio
->waiter
))
409 if (!(iocb
->ki_flags
& IOCB_HIPRI
) ||
410 !blk_mq_poll(bdev_get_queue(bdev
), qc
))
413 __set_current_state(TASK_RUNNING
);
415 ret
= dio
->bio
.bi_error
;
424 blkdev_direct_IO(struct kiocb
*iocb
, struct iov_iter
*iter
)
428 nr_pages
= iov_iter_npages(iter
, BIO_MAX_PAGES
+ 1);
431 if (is_sync_kiocb(iocb
) && nr_pages
<= BIO_MAX_PAGES
)
432 return __blkdev_direct_IO_simple(iocb
, iter
, nr_pages
);
434 return __blkdev_direct_IO(iocb
, iter
, min(nr_pages
, BIO_MAX_PAGES
));
437 static __init
int blkdev_init(void)
439 blkdev_dio_pool
= bioset_create(4, offsetof(struct blkdev_dio
, bio
));
440 if (!blkdev_dio_pool
)
444 module_init(blkdev_init
);
446 int __sync_blockdev(struct block_device
*bdev
, int wait
)
451 return filemap_flush(bdev
->bd_inode
->i_mapping
);
452 return filemap_write_and_wait(bdev
->bd_inode
->i_mapping
);
456 * Write out and wait upon all the dirty data associated with a block
457 * device via its mapping. Does not take the superblock lock.
459 int sync_blockdev(struct block_device
*bdev
)
461 return __sync_blockdev(bdev
, 1);
463 EXPORT_SYMBOL(sync_blockdev
);
466 * Write out and wait upon all dirty data associated with this
467 * device. Filesystem data as well as the underlying block
468 * device. Takes the superblock lock.
470 int fsync_bdev(struct block_device
*bdev
)
472 struct super_block
*sb
= get_super(bdev
);
474 int res
= sync_filesystem(sb
);
478 return sync_blockdev(bdev
);
480 EXPORT_SYMBOL(fsync_bdev
);
483 * freeze_bdev -- lock a filesystem and force it into a consistent state
484 * @bdev: blockdevice to lock
486 * If a superblock is found on this device, we take the s_umount semaphore
487 * on it to make sure nobody unmounts until the snapshot creation is done.
488 * The reference counter (bd_fsfreeze_count) guarantees that only the last
489 * unfreeze process can unfreeze the frozen filesystem actually when multiple
490 * freeze requests arrive simultaneously. It counts up in freeze_bdev() and
491 * count down in thaw_bdev(). When it becomes 0, thaw_bdev() will unfreeze
494 struct super_block
*freeze_bdev(struct block_device
*bdev
)
496 struct super_block
*sb
;
499 mutex_lock(&bdev
->bd_fsfreeze_mutex
);
500 if (++bdev
->bd_fsfreeze_count
> 1) {
502 * We don't even need to grab a reference - the first call
503 * to freeze_bdev grab an active reference and only the last
504 * thaw_bdev drops it.
506 sb
= get_super(bdev
);
509 mutex_unlock(&bdev
->bd_fsfreeze_mutex
);
513 sb
= get_active_super(bdev
);
516 if (sb
->s_op
->freeze_super
)
517 error
= sb
->s_op
->freeze_super(sb
);
519 error
= freeze_super(sb
);
521 deactivate_super(sb
);
522 bdev
->bd_fsfreeze_count
--;
523 mutex_unlock(&bdev
->bd_fsfreeze_mutex
);
524 return ERR_PTR(error
);
526 deactivate_super(sb
);
529 mutex_unlock(&bdev
->bd_fsfreeze_mutex
);
530 return sb
; /* thaw_bdev releases s->s_umount */
532 EXPORT_SYMBOL(freeze_bdev
);
535 * thaw_bdev -- unlock filesystem
536 * @bdev: blockdevice to unlock
537 * @sb: associated superblock
539 * Unlocks the filesystem and marks it writeable again after freeze_bdev().
541 int thaw_bdev(struct block_device
*bdev
, struct super_block
*sb
)
545 mutex_lock(&bdev
->bd_fsfreeze_mutex
);
546 if (!bdev
->bd_fsfreeze_count
)
550 if (--bdev
->bd_fsfreeze_count
> 0)
556 if (sb
->s_op
->thaw_super
)
557 error
= sb
->s_op
->thaw_super(sb
);
559 error
= thaw_super(sb
);
561 bdev
->bd_fsfreeze_count
++;
563 mutex_unlock(&bdev
->bd_fsfreeze_mutex
);
566 EXPORT_SYMBOL(thaw_bdev
);
568 static int blkdev_writepage(struct page
*page
, struct writeback_control
*wbc
)
570 return block_write_full_page(page
, blkdev_get_block
, wbc
);
573 static int blkdev_readpage(struct file
* file
, struct page
* page
)
575 return block_read_full_page(page
, blkdev_get_block
);
578 static int blkdev_readpages(struct file
*file
, struct address_space
*mapping
,
579 struct list_head
*pages
, unsigned nr_pages
)
581 return mpage_readpages(mapping
, pages
, nr_pages
, blkdev_get_block
);
584 static int blkdev_write_begin(struct file
*file
, struct address_space
*mapping
,
585 loff_t pos
, unsigned len
, unsigned flags
,
586 struct page
**pagep
, void **fsdata
)
588 return block_write_begin(mapping
, pos
, len
, flags
, pagep
,
592 static int blkdev_write_end(struct file
*file
, struct address_space
*mapping
,
593 loff_t pos
, unsigned len
, unsigned copied
,
594 struct page
*page
, void *fsdata
)
597 ret
= block_write_end(file
, mapping
, pos
, len
, copied
, page
, fsdata
);
607 * for a block special file file_inode(file)->i_size is zero
608 * so we compute the size by hand (just as in block_read/write above)
610 static loff_t
block_llseek(struct file
*file
, loff_t offset
, int whence
)
612 struct inode
*bd_inode
= bdev_file_inode(file
);
615 inode_lock(bd_inode
);
616 retval
= fixed_size_llseek(file
, offset
, whence
, i_size_read(bd_inode
));
617 inode_unlock(bd_inode
);
621 int blkdev_fsync(struct file
*filp
, loff_t start
, loff_t end
, int datasync
)
623 struct inode
*bd_inode
= bdev_file_inode(filp
);
624 struct block_device
*bdev
= I_BDEV(bd_inode
);
627 error
= filemap_write_and_wait_range(filp
->f_mapping
, start
, end
);
632 * There is no need to serialise calls to blkdev_issue_flush with
633 * i_mutex and doing so causes performance issues with concurrent
634 * O_SYNC writers to a block device.
636 error
= blkdev_issue_flush(bdev
, GFP_KERNEL
, NULL
);
637 if (error
== -EOPNOTSUPP
)
642 EXPORT_SYMBOL(blkdev_fsync
);
645 * bdev_read_page() - Start reading a page from a block device
646 * @bdev: The device to read the page from
647 * @sector: The offset on the device to read the page to (need not be aligned)
648 * @page: The page to read
650 * On entry, the page should be locked. It will be unlocked when the page
651 * has been read. If the block driver implements rw_page synchronously,
652 * that will be true on exit from this function, but it need not be.
654 * Errors returned by this function are usually "soft", eg out of memory, or
655 * queue full; callers should try a different route to read this page rather
656 * than propagate an error back up the stack.
658 * Return: negative errno if an error occurs, 0 if submission was successful.
660 int bdev_read_page(struct block_device
*bdev
, sector_t sector
,
663 const struct block_device_operations
*ops
= bdev
->bd_disk
->fops
;
664 int result
= -EOPNOTSUPP
;
666 if (!ops
->rw_page
|| bdev_get_integrity(bdev
))
669 result
= blk_queue_enter(bdev
->bd_queue
, false);
672 result
= ops
->rw_page(bdev
, sector
+ get_start_sect(bdev
), page
, false);
673 blk_queue_exit(bdev
->bd_queue
);
676 EXPORT_SYMBOL_GPL(bdev_read_page
);
679 * bdev_write_page() - Start writing a page to a block device
680 * @bdev: The device to write the page to
681 * @sector: The offset on the device to write the page to (need not be aligned)
682 * @page: The page to write
683 * @wbc: The writeback_control for the write
685 * On entry, the page should be locked and not currently under writeback.
686 * On exit, if the write started successfully, the page will be unlocked and
687 * under writeback. If the write failed already (eg the driver failed to
688 * queue the page to the device), the page will still be locked. If the
689 * caller is a ->writepage implementation, it will need to unlock the page.
691 * Errors returned by this function are usually "soft", eg out of memory, or
692 * queue full; callers should try a different route to write this page rather
693 * than propagate an error back up the stack.
695 * Return: negative errno if an error occurs, 0 if submission was successful.
697 int bdev_write_page(struct block_device
*bdev
, sector_t sector
,
698 struct page
*page
, struct writeback_control
*wbc
)
701 const struct block_device_operations
*ops
= bdev
->bd_disk
->fops
;
703 if (!ops
->rw_page
|| bdev_get_integrity(bdev
))
705 result
= blk_queue_enter(bdev
->bd_queue
, false);
709 set_page_writeback(page
);
710 result
= ops
->rw_page(bdev
, sector
+ get_start_sect(bdev
), page
, true);
712 end_page_writeback(page
);
715 blk_queue_exit(bdev
->bd_queue
);
718 EXPORT_SYMBOL_GPL(bdev_write_page
);
720 int bdev_dax_pgoff(struct block_device
*bdev
, sector_t sector
, size_t size
,
723 phys_addr_t phys_off
= (get_start_sect(bdev
) + sector
) * 512;
726 *pgoff
= PHYS_PFN(phys_off
);
727 if (phys_off
% PAGE_SIZE
|| size
% PAGE_SIZE
)
731 EXPORT_SYMBOL(bdev_dax_pgoff
);
734 * bdev_dax_supported() - Check if the device supports dax for filesystem
735 * @sb: The superblock of the device
736 * @blocksize: The block size of the device
738 * This is a library function for filesystems to check if the block device
739 * can be mounted with dax option.
741 * Return: negative errno if unsupported, 0 if supported.
743 int bdev_dax_supported(struct super_block
*sb
, int blocksize
)
745 struct block_device
*bdev
= sb
->s_bdev
;
746 struct dax_device
*dax_dev
;
753 if (blocksize
!= PAGE_SIZE
) {
754 vfs_msg(sb
, KERN_ERR
, "error: unsupported blocksize for dax");
758 err
= bdev_dax_pgoff(bdev
, 0, PAGE_SIZE
, &pgoff
);
760 vfs_msg(sb
, KERN_ERR
, "error: unaligned partition for dax");
764 dax_dev
= dax_get_by_host(bdev
->bd_disk
->disk_name
);
766 vfs_msg(sb
, KERN_ERR
, "error: device does not support dax");
770 id
= dax_read_lock();
771 len
= dax_direct_access(dax_dev
, pgoff
, 1, &kaddr
, &pfn
);
777 vfs_msg(sb
, KERN_ERR
,
778 "error: dax access failed (%ld)", len
);
779 return len
< 0 ? len
: -EIO
;
784 EXPORT_SYMBOL_GPL(bdev_dax_supported
);
790 static __cacheline_aligned_in_smp
DEFINE_SPINLOCK(bdev_lock
);
791 static struct kmem_cache
* bdev_cachep __read_mostly
;
793 static struct inode
*bdev_alloc_inode(struct super_block
*sb
)
795 struct bdev_inode
*ei
= kmem_cache_alloc(bdev_cachep
, GFP_KERNEL
);
798 return &ei
->vfs_inode
;
801 static void bdev_i_callback(struct rcu_head
*head
)
803 struct inode
*inode
= container_of(head
, struct inode
, i_rcu
);
804 struct bdev_inode
*bdi
= BDEV_I(inode
);
806 kmem_cache_free(bdev_cachep
, bdi
);
809 static void bdev_destroy_inode(struct inode
*inode
)
811 call_rcu(&inode
->i_rcu
, bdev_i_callback
);
814 static void init_once(void *foo
)
816 struct bdev_inode
*ei
= (struct bdev_inode
*) foo
;
817 struct block_device
*bdev
= &ei
->bdev
;
819 memset(bdev
, 0, sizeof(*bdev
));
820 mutex_init(&bdev
->bd_mutex
);
821 INIT_LIST_HEAD(&bdev
->bd_list
);
823 INIT_LIST_HEAD(&bdev
->bd_holder_disks
);
825 bdev
->bd_bdi
= &noop_backing_dev_info
;
826 inode_init_once(&ei
->vfs_inode
);
827 /* Initialize mutex for freeze. */
828 mutex_init(&bdev
->bd_fsfreeze_mutex
);
831 static void bdev_evict_inode(struct inode
*inode
)
833 struct block_device
*bdev
= &BDEV_I(inode
)->bdev
;
834 truncate_inode_pages_final(&inode
->i_data
);
835 invalidate_inode_buffers(inode
); /* is it needed here? */
837 spin_lock(&bdev_lock
);
838 list_del_init(&bdev
->bd_list
);
839 spin_unlock(&bdev_lock
);
840 /* Detach inode from wb early as bdi_put() may free bdi->wb */
841 inode_detach_wb(inode
);
842 if (bdev
->bd_bdi
!= &noop_backing_dev_info
) {
843 bdi_put(bdev
->bd_bdi
);
844 bdev
->bd_bdi
= &noop_backing_dev_info
;
848 static const struct super_operations bdev_sops
= {
849 .statfs
= simple_statfs
,
850 .alloc_inode
= bdev_alloc_inode
,
851 .destroy_inode
= bdev_destroy_inode
,
852 .drop_inode
= generic_delete_inode
,
853 .evict_inode
= bdev_evict_inode
,
856 static struct dentry
*bd_mount(struct file_system_type
*fs_type
,
857 int flags
, const char *dev_name
, void *data
)
860 dent
= mount_pseudo(fs_type
, "bdev:", &bdev_sops
, NULL
, BDEVFS_MAGIC
);
862 dent
->d_sb
->s_iflags
|= SB_I_CGROUPWB
;
866 static struct file_system_type bd_type
= {
869 .kill_sb
= kill_anon_super
,
872 struct super_block
*blockdev_superblock __read_mostly
;
873 EXPORT_SYMBOL_GPL(blockdev_superblock
);
875 void __init
bdev_cache_init(void)
878 static struct vfsmount
*bd_mnt
;
880 bdev_cachep
= kmem_cache_create("bdev_cache", sizeof(struct bdev_inode
),
881 0, (SLAB_HWCACHE_ALIGN
|SLAB_RECLAIM_ACCOUNT
|
882 SLAB_MEM_SPREAD
|SLAB_ACCOUNT
|SLAB_PANIC
),
884 err
= register_filesystem(&bd_type
);
886 panic("Cannot register bdev pseudo-fs");
887 bd_mnt
= kern_mount(&bd_type
);
889 panic("Cannot create bdev pseudo-fs");
890 blockdev_superblock
= bd_mnt
->mnt_sb
; /* For writeback */
894 * Most likely _very_ bad one - but then it's hardly critical for small
895 * /dev and can be fixed when somebody will need really large one.
896 * Keep in mind that it will be fed through icache hash function too.
898 static inline unsigned long hash(dev_t dev
)
900 return MAJOR(dev
)+MINOR(dev
);
903 static int bdev_test(struct inode
*inode
, void *data
)
905 return BDEV_I(inode
)->bdev
.bd_dev
== *(dev_t
*)data
;
908 static int bdev_set(struct inode
*inode
, void *data
)
910 BDEV_I(inode
)->bdev
.bd_dev
= *(dev_t
*)data
;
914 static LIST_HEAD(all_bdevs
);
917 * If there is a bdev inode for this device, unhash it so that it gets evicted
918 * as soon as last inode reference is dropped.
920 void bdev_unhash_inode(dev_t dev
)
924 inode
= ilookup5(blockdev_superblock
, hash(dev
), bdev_test
, &dev
);
926 remove_inode_hash(inode
);
931 struct block_device
*bdget(dev_t dev
)
933 struct block_device
*bdev
;
936 inode
= iget5_locked(blockdev_superblock
, hash(dev
),
937 bdev_test
, bdev_set
, &dev
);
942 bdev
= &BDEV_I(inode
)->bdev
;
944 if (inode
->i_state
& I_NEW
) {
945 bdev
->bd_contains
= NULL
;
946 bdev
->bd_super
= NULL
;
947 bdev
->bd_inode
= inode
;
948 bdev
->bd_block_size
= i_blocksize(inode
);
949 bdev
->bd_part_count
= 0;
950 bdev
->bd_invalidated
= 0;
951 inode
->i_mode
= S_IFBLK
;
953 inode
->i_bdev
= bdev
;
954 inode
->i_data
.a_ops
= &def_blk_aops
;
955 mapping_set_gfp_mask(&inode
->i_data
, GFP_USER
);
956 spin_lock(&bdev_lock
);
957 list_add(&bdev
->bd_list
, &all_bdevs
);
958 spin_unlock(&bdev_lock
);
959 unlock_new_inode(inode
);
964 EXPORT_SYMBOL(bdget
);
967 * bdgrab -- Grab a reference to an already referenced block device
968 * @bdev: Block device to grab a reference to.
970 struct block_device
*bdgrab(struct block_device
*bdev
)
972 ihold(bdev
->bd_inode
);
975 EXPORT_SYMBOL(bdgrab
);
977 long nr_blockdev_pages(void)
979 struct block_device
*bdev
;
981 spin_lock(&bdev_lock
);
982 list_for_each_entry(bdev
, &all_bdevs
, bd_list
) {
983 ret
+= bdev
->bd_inode
->i_mapping
->nrpages
;
985 spin_unlock(&bdev_lock
);
989 void bdput(struct block_device
*bdev
)
991 iput(bdev
->bd_inode
);
994 EXPORT_SYMBOL(bdput
);
996 static struct block_device
*bd_acquire(struct inode
*inode
)
998 struct block_device
*bdev
;
1000 spin_lock(&bdev_lock
);
1001 bdev
= inode
->i_bdev
;
1002 if (bdev
&& !inode_unhashed(bdev
->bd_inode
)) {
1004 spin_unlock(&bdev_lock
);
1007 spin_unlock(&bdev_lock
);
1010 * i_bdev references block device inode that was already shut down
1011 * (corresponding device got removed). Remove the reference and look
1012 * up block device inode again just in case new device got
1013 * reestablished under the same device number.
1018 bdev
= bdget(inode
->i_rdev
);
1020 spin_lock(&bdev_lock
);
1021 if (!inode
->i_bdev
) {
1023 * We take an additional reference to bd_inode,
1024 * and it's released in clear_inode() of inode.
1025 * So, we can access it via ->i_mapping always
1029 inode
->i_bdev
= bdev
;
1030 inode
->i_mapping
= bdev
->bd_inode
->i_mapping
;
1032 spin_unlock(&bdev_lock
);
1037 /* Call when you free inode */
1039 void bd_forget(struct inode
*inode
)
1041 struct block_device
*bdev
= NULL
;
1043 spin_lock(&bdev_lock
);
1044 if (!sb_is_blkdev_sb(inode
->i_sb
))
1045 bdev
= inode
->i_bdev
;
1046 inode
->i_bdev
= NULL
;
1047 inode
->i_mapping
= &inode
->i_data
;
1048 spin_unlock(&bdev_lock
);
1055 * bd_may_claim - test whether a block device can be claimed
1056 * @bdev: block device of interest
1057 * @whole: whole block device containing @bdev, may equal @bdev
1058 * @holder: holder trying to claim @bdev
1060 * Test whether @bdev can be claimed by @holder.
1063 * spin_lock(&bdev_lock).
1066 * %true if @bdev can be claimed, %false otherwise.
1068 static bool bd_may_claim(struct block_device
*bdev
, struct block_device
*whole
,
1071 if (bdev
->bd_holder
== holder
)
1072 return true; /* already a holder */
1073 else if (bdev
->bd_holder
!= NULL
)
1074 return false; /* held by someone else */
1075 else if (whole
== bdev
)
1076 return true; /* is a whole device which isn't held */
1078 else if (whole
->bd_holder
== bd_may_claim
)
1079 return true; /* is a partition of a device that is being partitioned */
1080 else if (whole
->bd_holder
!= NULL
)
1081 return false; /* is a partition of a held device */
1083 return true; /* is a partition of an un-held device */
1087 * bd_prepare_to_claim - prepare to claim a block device
1088 * @bdev: block device of interest
1089 * @whole: the whole device containing @bdev, may equal @bdev
1090 * @holder: holder trying to claim @bdev
1092 * Prepare to claim @bdev. This function fails if @bdev is already
1093 * claimed by another holder and waits if another claiming is in
1094 * progress. This function doesn't actually claim. On successful
1095 * return, the caller has ownership of bd_claiming and bd_holder[s].
1098 * spin_lock(&bdev_lock). Might release bdev_lock, sleep and regrab
1099 * it multiple times.
1102 * 0 if @bdev can be claimed, -EBUSY otherwise.
1104 static int bd_prepare_to_claim(struct block_device
*bdev
,
1105 struct block_device
*whole
, void *holder
)
1108 /* if someone else claimed, fail */
1109 if (!bd_may_claim(bdev
, whole
, holder
))
1112 /* if claiming is already in progress, wait for it to finish */
1113 if (whole
->bd_claiming
) {
1114 wait_queue_head_t
*wq
= bit_waitqueue(&whole
->bd_claiming
, 0);
1117 prepare_to_wait(wq
, &wait
, TASK_UNINTERRUPTIBLE
);
1118 spin_unlock(&bdev_lock
);
1120 finish_wait(wq
, &wait
);
1121 spin_lock(&bdev_lock
);
1130 * bd_start_claiming - start claiming a block device
1131 * @bdev: block device of interest
1132 * @holder: holder trying to claim @bdev
1134 * @bdev is about to be opened exclusively. Check @bdev can be opened
1135 * exclusively and mark that an exclusive open is in progress. Each
1136 * successful call to this function must be matched with a call to
1137 * either bd_finish_claiming() or bd_abort_claiming() (which do not
1140 * This function is used to gain exclusive access to the block device
1141 * without actually causing other exclusive open attempts to fail. It
1142 * should be used when the open sequence itself requires exclusive
1143 * access but may subsequently fail.
1149 * Pointer to the block device containing @bdev on success, ERR_PTR()
1152 static struct block_device
*bd_start_claiming(struct block_device
*bdev
,
1155 struct gendisk
*disk
;
1156 struct block_device
*whole
;
1162 * @bdev might not have been initialized properly yet, look up
1163 * and grab the outer block device the hard way.
1165 disk
= get_gendisk(bdev
->bd_dev
, &partno
);
1167 return ERR_PTR(-ENXIO
);
1170 * Normally, @bdev should equal what's returned from bdget_disk()
1171 * if partno is 0; however, some drivers (floppy) use multiple
1172 * bdev's for the same physical device and @bdev may be one of the
1173 * aliases. Keep @bdev if partno is 0. This means claimer
1174 * tracking is broken for those devices but it has always been that
1178 whole
= bdget_disk(disk
, 0);
1180 whole
= bdgrab(bdev
);
1182 module_put(disk
->fops
->owner
);
1185 return ERR_PTR(-ENOMEM
);
1187 /* prepare to claim, if successful, mark claiming in progress */
1188 spin_lock(&bdev_lock
);
1190 err
= bd_prepare_to_claim(bdev
, whole
, holder
);
1192 whole
->bd_claiming
= holder
;
1193 spin_unlock(&bdev_lock
);
1196 spin_unlock(&bdev_lock
);
1198 return ERR_PTR(err
);
1203 struct bd_holder_disk
{
1204 struct list_head list
;
1205 struct gendisk
*disk
;
1209 static struct bd_holder_disk
*bd_find_holder_disk(struct block_device
*bdev
,
1210 struct gendisk
*disk
)
1212 struct bd_holder_disk
*holder
;
1214 list_for_each_entry(holder
, &bdev
->bd_holder_disks
, list
)
1215 if (holder
->disk
== disk
)
1220 static int add_symlink(struct kobject
*from
, struct kobject
*to
)
1222 return sysfs_create_link(from
, to
, kobject_name(to
));
1225 static void del_symlink(struct kobject
*from
, struct kobject
*to
)
1227 sysfs_remove_link(from
, kobject_name(to
));
1231 * bd_link_disk_holder - create symlinks between holding disk and slave bdev
1232 * @bdev: the claimed slave bdev
1233 * @disk: the holding disk
1235 * DON'T USE THIS UNLESS YOU'RE ALREADY USING IT.
1237 * This functions creates the following sysfs symlinks.
1239 * - from "slaves" directory of the holder @disk to the claimed @bdev
1240 * - from "holders" directory of the @bdev to the holder @disk
1242 * For example, if /dev/dm-0 maps to /dev/sda and disk for dm-0 is
1243 * passed to bd_link_disk_holder(), then:
1245 * /sys/block/dm-0/slaves/sda --> /sys/block/sda
1246 * /sys/block/sda/holders/dm-0 --> /sys/block/dm-0
1248 * The caller must have claimed @bdev before calling this function and
1249 * ensure that both @bdev and @disk are valid during the creation and
1250 * lifetime of these symlinks.
1256 * 0 on success, -errno on failure.
1258 int bd_link_disk_holder(struct block_device
*bdev
, struct gendisk
*disk
)
1260 struct bd_holder_disk
*holder
;
1263 mutex_lock(&bdev
->bd_mutex
);
1265 WARN_ON_ONCE(!bdev
->bd_holder
);
1267 /* FIXME: remove the following once add_disk() handles errors */
1268 if (WARN_ON(!disk
->slave_dir
|| !bdev
->bd_part
->holder_dir
))
1271 holder
= bd_find_holder_disk(bdev
, disk
);
1277 holder
= kzalloc(sizeof(*holder
), GFP_KERNEL
);
1283 INIT_LIST_HEAD(&holder
->list
);
1284 holder
->disk
= disk
;
1287 ret
= add_symlink(disk
->slave_dir
, &part_to_dev(bdev
->bd_part
)->kobj
);
1291 ret
= add_symlink(bdev
->bd_part
->holder_dir
, &disk_to_dev(disk
)->kobj
);
1295 * bdev could be deleted beneath us which would implicitly destroy
1296 * the holder directory. Hold on to it.
1298 kobject_get(bdev
->bd_part
->holder_dir
);
1300 list_add(&holder
->list
, &bdev
->bd_holder_disks
);
1304 del_symlink(disk
->slave_dir
, &part_to_dev(bdev
->bd_part
)->kobj
);
1308 mutex_unlock(&bdev
->bd_mutex
);
1311 EXPORT_SYMBOL_GPL(bd_link_disk_holder
);
1314 * bd_unlink_disk_holder - destroy symlinks created by bd_link_disk_holder()
1315 * @bdev: the calimed slave bdev
1316 * @disk: the holding disk
1318 * DON'T USE THIS UNLESS YOU'RE ALREADY USING IT.
1323 void bd_unlink_disk_holder(struct block_device
*bdev
, struct gendisk
*disk
)
1325 struct bd_holder_disk
*holder
;
1327 mutex_lock(&bdev
->bd_mutex
);
1329 holder
= bd_find_holder_disk(bdev
, disk
);
1331 if (!WARN_ON_ONCE(holder
== NULL
) && !--holder
->refcnt
) {
1332 del_symlink(disk
->slave_dir
, &part_to_dev(bdev
->bd_part
)->kobj
);
1333 del_symlink(bdev
->bd_part
->holder_dir
,
1334 &disk_to_dev(disk
)->kobj
);
1335 kobject_put(bdev
->bd_part
->holder_dir
);
1336 list_del_init(&holder
->list
);
1340 mutex_unlock(&bdev
->bd_mutex
);
1342 EXPORT_SYMBOL_GPL(bd_unlink_disk_holder
);
1346 * flush_disk - invalidates all buffer-cache entries on a disk
1348 * @bdev: struct block device to be flushed
1349 * @kill_dirty: flag to guide handling of dirty inodes
1351 * Invalidates all buffer-cache entries on a disk. It should be called
1352 * when a disk has been changed -- either by a media change or online
1355 static void flush_disk(struct block_device
*bdev
, bool kill_dirty
)
1357 if (__invalidate_device(bdev
, kill_dirty
)) {
1358 printk(KERN_WARNING
"VFS: busy inodes on changed media or "
1359 "resized disk %s\n",
1360 bdev
->bd_disk
? bdev
->bd_disk
->disk_name
: "");
1365 if (disk_part_scan_enabled(bdev
->bd_disk
))
1366 bdev
->bd_invalidated
= 1;
1370 * check_disk_size_change - checks for disk size change and adjusts bdev size.
1371 * @disk: struct gendisk to check
1372 * @bdev: struct bdev to adjust.
1374 * This routine checks to see if the bdev size does not match the disk size
1375 * and adjusts it if it differs.
1377 void check_disk_size_change(struct gendisk
*disk
, struct block_device
*bdev
)
1379 loff_t disk_size
, bdev_size
;
1381 disk_size
= (loff_t
)get_capacity(disk
) << 9;
1382 bdev_size
= i_size_read(bdev
->bd_inode
);
1383 if (disk_size
!= bdev_size
) {
1385 "%s: detected capacity change from %lld to %lld\n",
1386 disk
->disk_name
, bdev_size
, disk_size
);
1387 i_size_write(bdev
->bd_inode
, disk_size
);
1388 flush_disk(bdev
, false);
1391 EXPORT_SYMBOL(check_disk_size_change
);
1394 * revalidate_disk - wrapper for lower-level driver's revalidate_disk call-back
1395 * @disk: struct gendisk to be revalidated
1397 * This routine is a wrapper for lower-level driver's revalidate_disk
1398 * call-backs. It is used to do common pre and post operations needed
1399 * for all revalidate_disk operations.
1401 int revalidate_disk(struct gendisk
*disk
)
1403 struct block_device
*bdev
;
1406 if (disk
->fops
->revalidate_disk
)
1407 ret
= disk
->fops
->revalidate_disk(disk
);
1408 bdev
= bdget_disk(disk
, 0);
1412 mutex_lock(&bdev
->bd_mutex
);
1413 check_disk_size_change(disk
, bdev
);
1414 bdev
->bd_invalidated
= 0;
1415 mutex_unlock(&bdev
->bd_mutex
);
1419 EXPORT_SYMBOL(revalidate_disk
);
1422 * This routine checks whether a removable media has been changed,
1423 * and invalidates all buffer-cache-entries in that case. This
1424 * is a relatively slow routine, so we have to try to minimize using
1425 * it. Thus it is called only upon a 'mount' or 'open'. This
1426 * is the best way of combining speed and utility, I think.
1427 * People changing diskettes in the middle of an operation deserve
1430 int check_disk_change(struct block_device
*bdev
)
1432 struct gendisk
*disk
= bdev
->bd_disk
;
1433 const struct block_device_operations
*bdops
= disk
->fops
;
1434 unsigned int events
;
1436 events
= disk_clear_events(disk
, DISK_EVENT_MEDIA_CHANGE
|
1437 DISK_EVENT_EJECT_REQUEST
);
1438 if (!(events
& DISK_EVENT_MEDIA_CHANGE
))
1441 flush_disk(bdev
, true);
1442 if (bdops
->revalidate_disk
)
1443 bdops
->revalidate_disk(bdev
->bd_disk
);
1447 EXPORT_SYMBOL(check_disk_change
);
1449 void bd_set_size(struct block_device
*bdev
, loff_t size
)
1451 unsigned bsize
= bdev_logical_block_size(bdev
);
1453 inode_lock(bdev
->bd_inode
);
1454 i_size_write(bdev
->bd_inode
, size
);
1455 inode_unlock(bdev
->bd_inode
);
1456 while (bsize
< PAGE_SIZE
) {
1461 bdev
->bd_block_size
= bsize
;
1462 bdev
->bd_inode
->i_blkbits
= blksize_bits(bsize
);
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
;
1478 struct module
*owner
;
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
= get_gendisk(bdev
->bd_dev
, &partno
);
1504 owner
= disk
->fops
->owner
;
1506 disk_block_events(disk
);
1507 mutex_lock_nested(&bdev
->bd_mutex
, for_part
);
1508 if (!bdev
->bd_openers
) {
1509 bdev
->bd_disk
= disk
;
1510 bdev
->bd_queue
= disk
->queue
;
1511 bdev
->bd_contains
= bdev
;
1515 bdev
->bd_part
= disk_get_part(disk
, partno
);
1520 if (disk
->fops
->open
) {
1521 ret
= disk
->fops
->open(bdev
, mode
);
1522 if (ret
== -ERESTARTSYS
) {
1523 /* Lost a race with 'disk' being
1524 * deleted, try again.
1527 disk_put_part(bdev
->bd_part
);
1528 bdev
->bd_part
= NULL
;
1529 bdev
->bd_disk
= NULL
;
1530 bdev
->bd_queue
= NULL
;
1531 mutex_unlock(&bdev
->bd_mutex
);
1532 disk_unblock_events(disk
);
1540 bd_set_size(bdev
,(loff_t
)get_capacity(disk
)<<9);
1543 * If the device is invalidated, rescan partition
1544 * if open succeeded or failed with -ENOMEDIUM.
1545 * The latter is necessary to prevent ghost
1546 * partitions on a removed medium.
1548 if (bdev
->bd_invalidated
) {
1550 rescan_partitions(disk
, bdev
);
1551 else if (ret
== -ENOMEDIUM
)
1552 invalidate_partitions(disk
, bdev
);
1558 struct block_device
*whole
;
1559 whole
= bdget_disk(disk
, 0);
1564 ret
= __blkdev_get(whole
, mode
, 1);
1567 bdev
->bd_contains
= whole
;
1568 bdev
->bd_part
= disk_get_part(disk
, partno
);
1569 if (!(disk
->flags
& GENHD_FL_UP
) ||
1570 !bdev
->bd_part
|| !bdev
->bd_part
->nr_sects
) {
1574 bd_set_size(bdev
, (loff_t
)bdev
->bd_part
->nr_sects
<< 9);
1577 if (bdev
->bd_bdi
== &noop_backing_dev_info
)
1578 bdev
->bd_bdi
= bdi_get(disk
->queue
->backing_dev_info
);
1580 if (bdev
->bd_contains
== bdev
) {
1582 if (bdev
->bd_disk
->fops
->open
)
1583 ret
= bdev
->bd_disk
->fops
->open(bdev
, mode
);
1584 /* the same as first opener case, read comment there */
1585 if (bdev
->bd_invalidated
) {
1587 rescan_partitions(bdev
->bd_disk
, bdev
);
1588 else if (ret
== -ENOMEDIUM
)
1589 invalidate_partitions(bdev
->bd_disk
, bdev
);
1592 goto out_unlock_bdev
;
1594 /* only one opener holds refs to the module and disk */
1600 bdev
->bd_part_count
++;
1601 mutex_unlock(&bdev
->bd_mutex
);
1602 disk_unblock_events(disk
);
1606 disk_put_part(bdev
->bd_part
);
1607 bdev
->bd_disk
= NULL
;
1608 bdev
->bd_part
= NULL
;
1609 bdev
->bd_queue
= NULL
;
1610 if (bdev
!= bdev
->bd_contains
)
1611 __blkdev_put(bdev
->bd_contains
, mode
, 1);
1612 bdev
->bd_contains
= NULL
;
1614 mutex_unlock(&bdev
->bd_mutex
);
1615 disk_unblock_events(disk
);
1625 * blkdev_get - open a block device
1626 * @bdev: block_device to open
1627 * @mode: FMODE_* mask
1628 * @holder: exclusive holder identifier
1630 * Open @bdev with @mode. If @mode includes %FMODE_EXCL, @bdev is
1631 * open with exclusive access. Specifying %FMODE_EXCL with %NULL
1632 * @holder is invalid. Exclusive opens may nest for the same @holder.
1634 * On success, the reference count of @bdev is unchanged. On failure,
1641 * 0 on success, -errno on failure.
1643 int blkdev_get(struct block_device
*bdev
, fmode_t mode
, void *holder
)
1645 struct block_device
*whole
= NULL
;
1648 WARN_ON_ONCE((mode
& FMODE_EXCL
) && !holder
);
1650 if ((mode
& FMODE_EXCL
) && holder
) {
1651 whole
= bd_start_claiming(bdev
, holder
);
1652 if (IS_ERR(whole
)) {
1654 return PTR_ERR(whole
);
1658 res
= __blkdev_get(bdev
, mode
, 0);
1661 struct gendisk
*disk
= whole
->bd_disk
;
1663 /* finish claiming */
1664 mutex_lock(&bdev
->bd_mutex
);
1665 spin_lock(&bdev_lock
);
1668 BUG_ON(!bd_may_claim(bdev
, whole
, holder
));
1670 * Note that for a whole device bd_holders
1671 * will be incremented twice, and bd_holder
1672 * will be set to bd_may_claim before being
1675 whole
->bd_holders
++;
1676 whole
->bd_holder
= bd_may_claim
;
1678 bdev
->bd_holder
= holder
;
1681 /* tell others that we're done */
1682 BUG_ON(whole
->bd_claiming
!= holder
);
1683 whole
->bd_claiming
= NULL
;
1684 wake_up_bit(&whole
->bd_claiming
, 0);
1686 spin_unlock(&bdev_lock
);
1689 * Block event polling for write claims if requested. Any
1690 * write holder makes the write_holder state stick until
1691 * all are released. This is good enough and tracking
1692 * individual writeable reference is too fragile given the
1693 * way @mode is used in blkdev_get/put().
1695 if (!res
&& (mode
& FMODE_WRITE
) && !bdev
->bd_write_holder
&&
1696 (disk
->flags
& GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE
)) {
1697 bdev
->bd_write_holder
= true;
1698 disk_block_events(disk
);
1701 mutex_unlock(&bdev
->bd_mutex
);
1707 EXPORT_SYMBOL(blkdev_get
);
1710 * blkdev_get_by_path - open a block device by name
1711 * @path: path to the block device to open
1712 * @mode: FMODE_* mask
1713 * @holder: exclusive holder identifier
1715 * Open the blockdevice described by the device file at @path. @mode
1716 * and @holder are identical to blkdev_get().
1718 * On success, the returned block_device has reference count of one.
1724 * Pointer to block_device on success, ERR_PTR(-errno) on failure.
1726 struct block_device
*blkdev_get_by_path(const char *path
, fmode_t mode
,
1729 struct block_device
*bdev
;
1732 bdev
= lookup_bdev(path
);
1736 err
= blkdev_get(bdev
, mode
, holder
);
1738 return ERR_PTR(err
);
1740 if ((mode
& FMODE_WRITE
) && bdev_read_only(bdev
)) {
1741 blkdev_put(bdev
, mode
);
1742 return ERR_PTR(-EACCES
);
1747 EXPORT_SYMBOL(blkdev_get_by_path
);
1750 * blkdev_get_by_dev - open a block device by device number
1751 * @dev: device number of block device to open
1752 * @mode: FMODE_* mask
1753 * @holder: exclusive holder identifier
1755 * Open the blockdevice described by device number @dev. @mode and
1756 * @holder are identical to blkdev_get().
1758 * Use it ONLY if you really do not have anything better - i.e. when
1759 * you are behind a truly sucky interface and all you are given is a
1760 * device number. _Never_ to be used for internal purposes. If you
1761 * ever need it - reconsider your API.
1763 * On success, the returned block_device has reference count of one.
1769 * Pointer to block_device on success, ERR_PTR(-errno) on failure.
1771 struct block_device
*blkdev_get_by_dev(dev_t dev
, fmode_t mode
, void *holder
)
1773 struct block_device
*bdev
;
1778 return ERR_PTR(-ENOMEM
);
1780 err
= blkdev_get(bdev
, mode
, holder
);
1782 return ERR_PTR(err
);
1786 EXPORT_SYMBOL(blkdev_get_by_dev
);
1788 static int blkdev_open(struct inode
* inode
, struct file
* filp
)
1790 struct block_device
*bdev
;
1793 * Preserve backwards compatibility and allow large file access
1794 * even if userspace doesn't ask for it explicitly. Some mkfs
1795 * binary needs it. We might want to drop this workaround
1796 * during an unstable branch.
1798 filp
->f_flags
|= O_LARGEFILE
;
1800 if (filp
->f_flags
& O_NDELAY
)
1801 filp
->f_mode
|= FMODE_NDELAY
;
1802 if (filp
->f_flags
& O_EXCL
)
1803 filp
->f_mode
|= FMODE_EXCL
;
1804 if ((filp
->f_flags
& O_ACCMODE
) == 3)
1805 filp
->f_mode
|= FMODE_WRITE_IOCTL
;
1807 bdev
= bd_acquire(inode
);
1811 filp
->f_mapping
= bdev
->bd_inode
->i_mapping
;
1813 return blkdev_get(bdev
, filp
->f_mode
, filp
);
1816 static void __blkdev_put(struct block_device
*bdev
, fmode_t mode
, int for_part
)
1818 struct gendisk
*disk
= bdev
->bd_disk
;
1819 struct block_device
*victim
= NULL
;
1821 mutex_lock_nested(&bdev
->bd_mutex
, for_part
);
1823 bdev
->bd_part_count
--;
1825 if (!--bdev
->bd_openers
) {
1826 WARN_ON_ONCE(bdev
->bd_holders
);
1827 sync_blockdev(bdev
);
1830 bdev_write_inode(bdev
);
1832 if (bdev
->bd_contains
== bdev
) {
1833 if (disk
->fops
->release
)
1834 disk
->fops
->release(disk
, mode
);
1836 if (!bdev
->bd_openers
) {
1837 struct module
*owner
= disk
->fops
->owner
;
1839 disk_put_part(bdev
->bd_part
);
1840 bdev
->bd_part
= NULL
;
1841 bdev
->bd_disk
= NULL
;
1842 if (bdev
!= bdev
->bd_contains
)
1843 victim
= bdev
->bd_contains
;
1844 bdev
->bd_contains
= NULL
;
1849 mutex_unlock(&bdev
->bd_mutex
);
1852 __blkdev_put(victim
, mode
, 1);
1855 void blkdev_put(struct block_device
*bdev
, fmode_t mode
)
1857 mutex_lock(&bdev
->bd_mutex
);
1859 if (mode
& FMODE_EXCL
) {
1863 * Release a claim on the device. The holder fields
1864 * are protected with bdev_lock. bd_mutex is to
1865 * synchronize disk_holder unlinking.
1867 spin_lock(&bdev_lock
);
1869 WARN_ON_ONCE(--bdev
->bd_holders
< 0);
1870 WARN_ON_ONCE(--bdev
->bd_contains
->bd_holders
< 0);
1872 /* bd_contains might point to self, check in a separate step */
1873 if ((bdev_free
= !bdev
->bd_holders
))
1874 bdev
->bd_holder
= NULL
;
1875 if (!bdev
->bd_contains
->bd_holders
)
1876 bdev
->bd_contains
->bd_holder
= NULL
;
1878 spin_unlock(&bdev_lock
);
1881 * If this was the last claim, remove holder link and
1882 * unblock evpoll if it was a write holder.
1884 if (bdev_free
&& bdev
->bd_write_holder
) {
1885 disk_unblock_events(bdev
->bd_disk
);
1886 bdev
->bd_write_holder
= false;
1891 * Trigger event checking and tell drivers to flush MEDIA_CHANGE
1892 * event. This is to ensure detection of media removal commanded
1893 * from userland - e.g. eject(1).
1895 disk_flush_events(bdev
->bd_disk
, DISK_EVENT_MEDIA_CHANGE
);
1897 mutex_unlock(&bdev
->bd_mutex
);
1899 __blkdev_put(bdev
, mode
, 0);
1901 EXPORT_SYMBOL(blkdev_put
);
1903 static int blkdev_close(struct inode
* inode
, struct file
* filp
)
1905 struct block_device
*bdev
= I_BDEV(bdev_file_inode(filp
));
1906 blkdev_put(bdev
, filp
->f_mode
);
1910 static long block_ioctl(struct file
*file
, unsigned cmd
, unsigned long arg
)
1912 struct block_device
*bdev
= I_BDEV(bdev_file_inode(file
));
1913 fmode_t mode
= file
->f_mode
;
1916 * O_NDELAY can be altered using fcntl(.., F_SETFL, ..), so we have
1917 * to updated it before every ioctl.
1919 if (file
->f_flags
& O_NDELAY
)
1920 mode
|= FMODE_NDELAY
;
1922 mode
&= ~FMODE_NDELAY
;
1924 return blkdev_ioctl(bdev
, mode
, cmd
, arg
);
1928 * Write data to the block device. Only intended for the block device itself
1929 * and the raw driver which basically is a fake block device.
1931 * Does not take i_mutex for the write and thus is not for general purpose
1934 ssize_t
blkdev_write_iter(struct kiocb
*iocb
, struct iov_iter
*from
)
1936 struct file
*file
= iocb
->ki_filp
;
1937 struct inode
*bd_inode
= bdev_file_inode(file
);
1938 loff_t size
= i_size_read(bd_inode
);
1939 struct blk_plug plug
;
1942 if (bdev_read_only(I_BDEV(bd_inode
)))
1945 if (!iov_iter_count(from
))
1948 if (iocb
->ki_pos
>= size
)
1951 iov_iter_truncate(from
, size
- iocb
->ki_pos
);
1953 blk_start_plug(&plug
);
1954 ret
= __generic_file_write_iter(iocb
, from
);
1956 ret
= generic_write_sync(iocb
, ret
);
1957 blk_finish_plug(&plug
);
1960 EXPORT_SYMBOL_GPL(blkdev_write_iter
);
1962 ssize_t
blkdev_read_iter(struct kiocb
*iocb
, struct iov_iter
*to
)
1964 struct file
*file
= iocb
->ki_filp
;
1965 struct inode
*bd_inode
= bdev_file_inode(file
);
1966 loff_t size
= i_size_read(bd_inode
);
1967 loff_t pos
= iocb
->ki_pos
;
1973 iov_iter_truncate(to
, size
);
1974 return generic_file_read_iter(iocb
, to
);
1976 EXPORT_SYMBOL_GPL(blkdev_read_iter
);
1979 * Try to release a page associated with block device when the system
1980 * is under memory pressure.
1982 static int blkdev_releasepage(struct page
*page
, gfp_t wait
)
1984 struct super_block
*super
= BDEV_I(page
->mapping
->host
)->bdev
.bd_super
;
1986 if (super
&& super
->s_op
->bdev_try_to_free_page
)
1987 return super
->s_op
->bdev_try_to_free_page(super
, page
, wait
);
1989 return try_to_free_buffers(page
);
1992 static int blkdev_writepages(struct address_space
*mapping
,
1993 struct writeback_control
*wbc
)
1995 if (dax_mapping(mapping
)) {
1996 struct block_device
*bdev
= I_BDEV(mapping
->host
);
1998 return dax_writeback_mapping_range(mapping
, bdev
, 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 .is_dirty_writeback
= buffer_check_dirty_writeback
,
2015 #define BLKDEV_FALLOC_FL_SUPPORTED \
2016 (FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE | \
2017 FALLOC_FL_ZERO_RANGE | FALLOC_FL_NO_HIDE_STALE)
2019 static long blkdev_fallocate(struct file
*file
, int mode
, loff_t start
,
2022 struct block_device
*bdev
= I_BDEV(bdev_file_inode(file
));
2023 struct address_space
*mapping
;
2024 loff_t end
= start
+ len
- 1;
2028 /* Fail if we don't recognize the flags. */
2029 if (mode
& ~BLKDEV_FALLOC_FL_SUPPORTED
)
2032 /* Don't go off the end of the device. */
2033 isize
= i_size_read(bdev
->bd_inode
);
2037 if (mode
& FALLOC_FL_KEEP_SIZE
) {
2038 len
= isize
- start
;
2039 end
= start
+ len
- 1;
2045 * Don't allow IO that isn't aligned to logical block size.
2047 if ((start
| len
) & (bdev_logical_block_size(bdev
) - 1))
2050 /* Invalidate the page cache, including dirty pages. */
2051 mapping
= bdev
->bd_inode
->i_mapping
;
2052 truncate_inode_pages_range(mapping
, start
, end
);
2055 case FALLOC_FL_ZERO_RANGE
:
2056 case FALLOC_FL_ZERO_RANGE
| FALLOC_FL_KEEP_SIZE
:
2057 error
= blkdev_issue_zeroout(bdev
, start
>> 9, len
>> 9,
2058 GFP_KERNEL
, BLKDEV_ZERO_NOUNMAP
);
2060 case FALLOC_FL_PUNCH_HOLE
| FALLOC_FL_KEEP_SIZE
:
2061 error
= blkdev_issue_zeroout(bdev
, start
>> 9, len
>> 9,
2062 GFP_KERNEL
, BLKDEV_ZERO_NOFALLBACK
);
2064 case FALLOC_FL_PUNCH_HOLE
| FALLOC_FL_KEEP_SIZE
| FALLOC_FL_NO_HIDE_STALE
:
2065 error
= blkdev_issue_discard(bdev
, start
>> 9, len
>> 9,
2075 * Invalidate again; if someone wandered in and dirtied a page,
2076 * the caller will be given -EBUSY. The third argument is
2077 * inclusive, so the rounding here is safe.
2079 return invalidate_inode_pages2_range(mapping
,
2080 start
>> PAGE_SHIFT
,
2084 const struct file_operations def_blk_fops
= {
2085 .open
= blkdev_open
,
2086 .release
= blkdev_close
,
2087 .llseek
= block_llseek
,
2088 .read_iter
= blkdev_read_iter
,
2089 .write_iter
= blkdev_write_iter
,
2090 .mmap
= generic_file_mmap
,
2091 .fsync
= blkdev_fsync
,
2092 .unlocked_ioctl
= block_ioctl
,
2093 #ifdef CONFIG_COMPAT
2094 .compat_ioctl
= compat_blkdev_ioctl
,
2096 .splice_read
= generic_file_splice_read
,
2097 .splice_write
= iter_file_splice_write
,
2098 .fallocate
= blkdev_fallocate
,
2101 int ioctl_by_bdev(struct block_device
*bdev
, unsigned cmd
, unsigned long arg
)
2104 mm_segment_t old_fs
= get_fs();
2106 res
= blkdev_ioctl(bdev
, 0, cmd
, arg
);
2111 EXPORT_SYMBOL(ioctl_by_bdev
);
2114 * lookup_bdev - lookup a struct block_device by name
2115 * @pathname: special file representing the block device
2117 * Get a reference to the blockdevice at @pathname in the current
2118 * namespace if possible and return it. Return ERR_PTR(error)
2121 struct block_device
*lookup_bdev(const char *pathname
)
2123 struct block_device
*bdev
;
2124 struct inode
*inode
;
2128 if (!pathname
|| !*pathname
)
2129 return ERR_PTR(-EINVAL
);
2131 error
= kern_path(pathname
, LOOKUP_FOLLOW
, &path
);
2133 return ERR_PTR(error
);
2135 inode
= d_backing_inode(path
.dentry
);
2137 if (!S_ISBLK(inode
->i_mode
))
2140 if (!may_open_dev(&path
))
2143 bdev
= bd_acquire(inode
);
2150 bdev
= ERR_PTR(error
);
2153 EXPORT_SYMBOL(lookup_bdev
);
2155 int __invalidate_device(struct block_device
*bdev
, bool kill_dirty
)
2157 struct super_block
*sb
= get_super(bdev
);
2162 * no need to lock the super, get_super holds the
2163 * read mutex so the filesystem cannot go away
2164 * under us (->put_super runs with the write lock
2167 shrink_dcache_sb(sb
);
2168 res
= invalidate_inodes(sb
, kill_dirty
);
2171 invalidate_bdev(bdev
);
2174 EXPORT_SYMBOL(__invalidate_device
);
2176 void iterate_bdevs(void (*func
)(struct block_device
*, void *), void *arg
)
2178 struct inode
*inode
, *old_inode
= NULL
;
2180 spin_lock(&blockdev_superblock
->s_inode_list_lock
);
2181 list_for_each_entry(inode
, &blockdev_superblock
->s_inodes
, i_sb_list
) {
2182 struct address_space
*mapping
= inode
->i_mapping
;
2183 struct block_device
*bdev
;
2185 spin_lock(&inode
->i_lock
);
2186 if (inode
->i_state
& (I_FREEING
|I_WILL_FREE
|I_NEW
) ||
2187 mapping
->nrpages
== 0) {
2188 spin_unlock(&inode
->i_lock
);
2192 spin_unlock(&inode
->i_lock
);
2193 spin_unlock(&blockdev_superblock
->s_inode_list_lock
);
2195 * We hold a reference to 'inode' so it couldn't have been
2196 * removed from s_inodes list while we dropped the
2197 * s_inode_list_lock We cannot iput the inode now as we can
2198 * be holding the last reference and we cannot iput it under
2199 * s_inode_list_lock. So we keep the reference and iput it
2204 bdev
= I_BDEV(inode
);
2206 mutex_lock(&bdev
->bd_mutex
);
2207 if (bdev
->bd_openers
)
2209 mutex_unlock(&bdev
->bd_mutex
);
2211 spin_lock(&blockdev_superblock
->s_inode_list_lock
);
2213 spin_unlock(&blockdev_superblock
->s_inode_list_lock
);