4 * Copyright (C) 1991, 1992 Linus Torvalds
5 * Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE
8 #include <linux/init.h>
10 #include <linux/fcntl.h>
11 #include <linux/slab.h>
12 #include <linux/kmod.h>
13 #include <linux/major.h>
14 #include <linux/smp_lock.h>
15 #include <linux/device_cgroup.h>
16 #include <linux/highmem.h>
17 #include <linux/blkdev.h>
18 #include <linux/module.h>
19 #include <linux/blkpg.h>
20 #include <linux/buffer_head.h>
21 #include <linux/pagevec.h>
22 #include <linux/writeback.h>
23 #include <linux/mpage.h>
24 #include <linux/mount.h>
25 #include <linux/uio.h>
26 #include <linux/namei.h>
27 #include <linux/log2.h>
28 #include <linux/kmemleak.h>
29 #include <asm/uaccess.h>
33 struct block_device bdev;
34 struct inode vfs_inode;
37 static const struct address_space_operations def_blk_aops;
39 static inline struct bdev_inode *BDEV_I(struct inode *inode)
41 return container_of(inode, struct bdev_inode, vfs_inode);
44 inline struct block_device *I_BDEV(struct inode *inode)
46 return &BDEV_I(inode)->bdev;
49 EXPORT_SYMBOL(I_BDEV);
51 static sector_t max_block(struct block_device *bdev)
53 sector_t retval = ~((sector_t)0);
54 loff_t sz = i_size_read(bdev->bd_inode);
57 unsigned int size = block_size(bdev);
58 unsigned int sizebits = blksize_bits(size);
59 retval = (sz >> sizebits);
64 /* Kill _all_ buffers and pagecache , dirty or not.. */
65 static void kill_bdev(struct block_device *bdev)
67 if (bdev->bd_inode->i_mapping->nrpages == 0)
70 truncate_inode_pages(bdev->bd_inode->i_mapping, 0);
73 int set_blocksize(struct block_device *bdev, int size)
75 /* Size must be a power of two, and between 512 and PAGE_SIZE */
76 if (size > PAGE_SIZE || size < 512 || !is_power_of_2(size))
79 /* Size cannot be smaller than the size supported by the device */
80 if (size < bdev_logical_block_size(bdev))
83 /* Don't change the size if it is same as current */
84 if (bdev->bd_block_size != size) {
86 bdev->bd_block_size = size;
87 bdev->bd_inode->i_blkbits = blksize_bits(size);
93 EXPORT_SYMBOL(set_blocksize);
95 int sb_set_blocksize(struct super_block *sb, int size)
97 if (set_blocksize(sb->s_bdev, size))
99 /* If we get here, we know size is power of two
100 * and it's value is between 512 and PAGE_SIZE */
101 sb->s_blocksize = size;
102 sb->s_blocksize_bits = blksize_bits(size);
103 return sb->s_blocksize;
106 EXPORT_SYMBOL(sb_set_blocksize);
108 int sb_min_blocksize(struct super_block *sb, int size)
110 int minsize = bdev_logical_block_size(sb->s_bdev);
113 return sb_set_blocksize(sb, size);
116 EXPORT_SYMBOL(sb_min_blocksize);
119 blkdev_get_block(struct inode *inode, sector_t iblock,
120 struct buffer_head *bh, int create)
122 if (iblock >= max_block(I_BDEV(inode))) {
127 * for reads, we're just trying to fill a partial page.
128 * return a hole, they will have to call get_block again
129 * before they can fill it, and they will get -EIO at that
134 bh->b_bdev = I_BDEV(inode);
135 bh->b_blocknr = iblock;
136 set_buffer_mapped(bh);
141 blkdev_get_blocks(struct inode *inode, sector_t iblock,
142 struct buffer_head *bh, int create)
144 sector_t end_block = max_block(I_BDEV(inode));
145 unsigned long max_blocks = bh->b_size >> inode->i_blkbits;
147 if ((iblock + max_blocks) > end_block) {
148 max_blocks = end_block - iblock;
149 if ((long)max_blocks <= 0) {
151 return -EIO; /* write fully beyond EOF */
153 * It is a read which is fully beyond EOF. We return
154 * a !buffer_mapped buffer
160 bh->b_bdev = I_BDEV(inode);
161 bh->b_blocknr = iblock;
162 bh->b_size = max_blocks << inode->i_blkbits;
164 set_buffer_mapped(bh);
169 blkdev_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
170 loff_t offset, unsigned long nr_segs)
172 struct file *file = iocb->ki_filp;
173 struct inode *inode = file->f_mapping->host;
175 return blockdev_direct_IO_no_locking_newtrunc(rw, iocb, inode,
176 I_BDEV(inode), iov, offset, nr_segs,
177 blkdev_get_blocks, NULL);
180 int __sync_blockdev(struct block_device *bdev, int wait)
185 return filemap_flush(bdev->bd_inode->i_mapping);
186 return filemap_write_and_wait(bdev->bd_inode->i_mapping);
190 * Write out and wait upon all the dirty data associated with a block
191 * device via its mapping. Does not take the superblock lock.
193 int sync_blockdev(struct block_device *bdev)
195 return __sync_blockdev(bdev, 1);
197 EXPORT_SYMBOL(sync_blockdev);
200 * Write out and wait upon all dirty data associated with this
201 * device. Filesystem data as well as the underlying block
202 * device. Takes the superblock lock.
204 int fsync_bdev(struct block_device *bdev)
206 struct super_block *sb = get_super(bdev);
208 int res = sync_filesystem(sb);
212 return sync_blockdev(bdev);
214 EXPORT_SYMBOL(fsync_bdev);
217 * freeze_bdev -- lock a filesystem and force it into a consistent state
218 * @bdev: blockdevice to lock
220 * If a superblock is found on this device, we take the s_umount semaphore
221 * on it to make sure nobody unmounts until the snapshot creation is done.
222 * The reference counter (bd_fsfreeze_count) guarantees that only the last
223 * unfreeze process can unfreeze the frozen filesystem actually when multiple
224 * freeze requests arrive simultaneously. It counts up in freeze_bdev() and
225 * count down in thaw_bdev(). When it becomes 0, thaw_bdev() will unfreeze
228 struct super_block *freeze_bdev(struct block_device *bdev)
230 struct super_block *sb;
233 mutex_lock(&bdev->bd_fsfreeze_mutex);
234 if (++bdev->bd_fsfreeze_count > 1) {
236 * We don't even need to grab a reference - the first call
237 * to freeze_bdev grab an active reference and only the last
238 * thaw_bdev drops it.
240 sb = get_super(bdev);
242 mutex_unlock(&bdev->bd_fsfreeze_mutex);
246 sb = get_active_super(bdev);
249 error = freeze_super(sb);
251 deactivate_super(sb);
252 bdev->bd_fsfreeze_count--;
253 mutex_unlock(&bdev->bd_fsfreeze_mutex);
254 return ERR_PTR(error);
256 deactivate_super(sb);
259 mutex_unlock(&bdev->bd_fsfreeze_mutex);
260 return sb; /* thaw_bdev releases s->s_umount */
262 EXPORT_SYMBOL(freeze_bdev);
265 * thaw_bdev -- unlock filesystem
266 * @bdev: blockdevice to unlock
267 * @sb: associated superblock
269 * Unlocks the filesystem and marks it writeable again after freeze_bdev().
271 int thaw_bdev(struct block_device *bdev, struct super_block *sb)
275 mutex_lock(&bdev->bd_fsfreeze_mutex);
276 if (!bdev->bd_fsfreeze_count)
280 if (--bdev->bd_fsfreeze_count > 0)
286 error = thaw_super(sb);
288 bdev->bd_fsfreeze_count++;
289 mutex_unlock(&bdev->bd_fsfreeze_mutex);
293 mutex_unlock(&bdev->bd_fsfreeze_mutex);
296 EXPORT_SYMBOL(thaw_bdev);
298 static int blkdev_writepage(struct page *page, struct writeback_control *wbc)
300 return block_write_full_page(page, blkdev_get_block, wbc);
303 static int blkdev_readpage(struct file * file, struct page * page)
305 return block_read_full_page(page, blkdev_get_block);
308 static int blkdev_write_begin(struct file *file, struct address_space *mapping,
309 loff_t pos, unsigned len, unsigned flags,
310 struct page **pagep, void **fsdata)
313 return block_write_begin_newtrunc(file, mapping, pos, len, flags,
314 pagep, fsdata, blkdev_get_block);
317 static int blkdev_write_end(struct file *file, struct address_space *mapping,
318 loff_t pos, unsigned len, unsigned copied,
319 struct page *page, void *fsdata)
322 ret = block_write_end(file, mapping, pos, len, copied, page, fsdata);
325 page_cache_release(page);
332 * for a block special file file->f_path.dentry->d_inode->i_size is zero
333 * so we compute the size by hand (just as in block_read/write above)
335 static loff_t block_llseek(struct file *file, loff_t offset, int origin)
337 struct inode *bd_inode = file->f_mapping->host;
341 mutex_lock(&bd_inode->i_mutex);
342 size = i_size_read(bd_inode);
349 offset += file->f_pos;
352 if (offset >= 0 && offset <= size) {
353 if (offset != file->f_pos) {
354 file->f_pos = offset;
358 mutex_unlock(&bd_inode->i_mutex);
362 int blkdev_fsync(struct file *filp, int datasync)
364 struct inode *bd_inode = filp->f_mapping->host;
365 struct block_device *bdev = I_BDEV(bd_inode);
369 * There is no need to serialise calls to blkdev_issue_flush with
370 * i_mutex and doing so causes performance issues with concurrent
371 * O_SYNC writers to a block device.
373 mutex_unlock(&bd_inode->i_mutex);
375 error = blkdev_issue_flush(bdev, GFP_KERNEL, NULL, BLKDEV_IFL_WAIT);
376 if (error == -EOPNOTSUPP)
379 mutex_lock(&bd_inode->i_mutex);
383 EXPORT_SYMBOL(blkdev_fsync);
389 static __cacheline_aligned_in_smp DEFINE_SPINLOCK(bdev_lock);
390 static struct kmem_cache * bdev_cachep __read_mostly;
392 static struct inode *bdev_alloc_inode(struct super_block *sb)
394 struct bdev_inode *ei = kmem_cache_alloc(bdev_cachep, GFP_KERNEL);
397 return &ei->vfs_inode;
400 static void bdev_destroy_inode(struct inode *inode)
402 struct bdev_inode *bdi = BDEV_I(inode);
404 kmem_cache_free(bdev_cachep, bdi);
407 static void init_once(void *foo)
409 struct bdev_inode *ei = (struct bdev_inode *) foo;
410 struct block_device *bdev = &ei->bdev;
412 memset(bdev, 0, sizeof(*bdev));
413 mutex_init(&bdev->bd_mutex);
414 INIT_LIST_HEAD(&bdev->bd_inodes);
415 INIT_LIST_HEAD(&bdev->bd_list);
417 INIT_LIST_HEAD(&bdev->bd_holder_list);
419 inode_init_once(&ei->vfs_inode);
420 /* Initialize mutex for freeze. */
421 mutex_init(&bdev->bd_fsfreeze_mutex);
424 static inline void __bd_forget(struct inode *inode)
426 list_del_init(&inode->i_devices);
427 inode->i_bdev = NULL;
428 inode->i_mapping = &inode->i_data;
431 static void bdev_clear_inode(struct inode *inode)
433 struct block_device *bdev = &BDEV_I(inode)->bdev;
435 spin_lock(&bdev_lock);
436 while ( (p = bdev->bd_inodes.next) != &bdev->bd_inodes ) {
437 __bd_forget(list_entry(p, struct inode, i_devices));
439 list_del_init(&bdev->bd_list);
440 spin_unlock(&bdev_lock);
443 static const struct super_operations bdev_sops = {
444 .statfs = simple_statfs,
445 .alloc_inode = bdev_alloc_inode,
446 .destroy_inode = bdev_destroy_inode,
447 .drop_inode = generic_delete_inode,
448 .clear_inode = bdev_clear_inode,
451 static int bd_get_sb(struct file_system_type *fs_type,
452 int flags, const char *dev_name, void *data, struct vfsmount *mnt)
454 return get_sb_pseudo(fs_type, "bdev:", &bdev_sops, 0x62646576, mnt);
457 static struct file_system_type bd_type = {
460 .kill_sb = kill_anon_super,
463 struct super_block *blockdev_superblock __read_mostly;
465 void __init bdev_cache_init(void)
468 struct vfsmount *bd_mnt;
470 bdev_cachep = kmem_cache_create("bdev_cache", sizeof(struct bdev_inode),
471 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
472 SLAB_MEM_SPREAD|SLAB_PANIC),
474 err = register_filesystem(&bd_type);
476 panic("Cannot register bdev pseudo-fs");
477 bd_mnt = kern_mount(&bd_type);
479 panic("Cannot create bdev pseudo-fs");
481 * This vfsmount structure is only used to obtain the
482 * blockdev_superblock, so tell kmemleak not to report it.
484 kmemleak_not_leak(bd_mnt);
485 blockdev_superblock = bd_mnt->mnt_sb; /* For writeback */
489 * Most likely _very_ bad one - but then it's hardly critical for small
490 * /dev and can be fixed when somebody will need really large one.
491 * Keep in mind that it will be fed through icache hash function too.
493 static inline unsigned long hash(dev_t dev)
495 return MAJOR(dev)+MINOR(dev);
498 static int bdev_test(struct inode *inode, void *data)
500 return BDEV_I(inode)->bdev.bd_dev == *(dev_t *)data;
503 static int bdev_set(struct inode *inode, void *data)
505 BDEV_I(inode)->bdev.bd_dev = *(dev_t *)data;
509 static LIST_HEAD(all_bdevs);
511 struct block_device *bdget(dev_t dev)
513 struct block_device *bdev;
516 inode = iget5_locked(blockdev_superblock, hash(dev),
517 bdev_test, bdev_set, &dev);
522 bdev = &BDEV_I(inode)->bdev;
524 if (inode->i_state & I_NEW) {
525 bdev->bd_contains = NULL;
526 bdev->bd_inode = inode;
527 bdev->bd_block_size = (1 << inode->i_blkbits);
528 bdev->bd_part_count = 0;
529 bdev->bd_invalidated = 0;
530 inode->i_mode = S_IFBLK;
532 inode->i_bdev = bdev;
533 inode->i_data.a_ops = &def_blk_aops;
534 mapping_set_gfp_mask(&inode->i_data, GFP_USER);
535 inode->i_data.backing_dev_info = &default_backing_dev_info;
536 spin_lock(&bdev_lock);
537 list_add(&bdev->bd_list, &all_bdevs);
538 spin_unlock(&bdev_lock);
539 unlock_new_inode(inode);
544 EXPORT_SYMBOL(bdget);
547 * bdgrab -- Grab a reference to an already referenced block device
548 * @bdev: Block device to grab a reference to.
550 struct block_device *bdgrab(struct block_device *bdev)
552 atomic_inc(&bdev->bd_inode->i_count);
556 long nr_blockdev_pages(void)
558 struct block_device *bdev;
560 spin_lock(&bdev_lock);
561 list_for_each_entry(bdev, &all_bdevs, bd_list) {
562 ret += bdev->bd_inode->i_mapping->nrpages;
564 spin_unlock(&bdev_lock);
568 void bdput(struct block_device *bdev)
570 iput(bdev->bd_inode);
573 EXPORT_SYMBOL(bdput);
575 static struct block_device *bd_acquire(struct inode *inode)
577 struct block_device *bdev;
579 spin_lock(&bdev_lock);
580 bdev = inode->i_bdev;
582 atomic_inc(&bdev->bd_inode->i_count);
583 spin_unlock(&bdev_lock);
586 spin_unlock(&bdev_lock);
588 bdev = bdget(inode->i_rdev);
590 spin_lock(&bdev_lock);
591 if (!inode->i_bdev) {
593 * We take an additional bd_inode->i_count for inode,
594 * and it's released in clear_inode() of inode.
595 * So, we can access it via ->i_mapping always
598 atomic_inc(&bdev->bd_inode->i_count);
599 inode->i_bdev = bdev;
600 inode->i_mapping = bdev->bd_inode->i_mapping;
601 list_add(&inode->i_devices, &bdev->bd_inodes);
603 spin_unlock(&bdev_lock);
608 /* Call when you free inode */
610 void bd_forget(struct inode *inode)
612 struct block_device *bdev = NULL;
614 spin_lock(&bdev_lock);
616 if (!sb_is_blkdev_sb(inode->i_sb))
617 bdev = inode->i_bdev;
620 spin_unlock(&bdev_lock);
623 iput(bdev->bd_inode);
627 * bd_may_claim - test whether a block device can be claimed
628 * @bdev: block device of interest
629 * @whole: whole block device containing @bdev, may equal @bdev
630 * @holder: holder trying to claim @bdev
632 * Test whther @bdev can be claimed by @holder.
635 * spin_lock(&bdev_lock).
638 * %true if @bdev can be claimed, %false otherwise.
640 static bool bd_may_claim(struct block_device *bdev, struct block_device *whole,
643 if (bdev->bd_holder == holder)
644 return true; /* already a holder */
645 else if (bdev->bd_holder != NULL)
646 return false; /* held by someone else */
647 else if (bdev->bd_contains == bdev)
648 return true; /* is a whole device which isn't held */
650 else if (whole->bd_holder == bd_claim)
651 return true; /* is a partition of a device that is being partitioned */
652 else if (whole->bd_holder != NULL)
653 return false; /* is a partition of a held device */
655 return true; /* is a partition of an un-held device */
659 * bd_prepare_to_claim - prepare to claim a block device
660 * @bdev: block device of interest
661 * @whole: the whole device containing @bdev, may equal @bdev
662 * @holder: holder trying to claim @bdev
664 * Prepare to claim @bdev. This function fails if @bdev is already
665 * claimed by another holder and waits if another claiming is in
666 * progress. This function doesn't actually claim. On successful
667 * return, the caller has ownership of bd_claiming and bd_holder[s].
670 * spin_lock(&bdev_lock). Might release bdev_lock, sleep and regrab
674 * 0 if @bdev can be claimed, -EBUSY otherwise.
676 static int bd_prepare_to_claim(struct block_device *bdev,
677 struct block_device *whole, void *holder)
680 /* if someone else claimed, fail */
681 if (!bd_may_claim(bdev, whole, holder))
684 /* if someone else is claiming, wait for it to finish */
685 if (whole->bd_claiming && whole->bd_claiming != holder) {
686 wait_queue_head_t *wq = bit_waitqueue(&whole->bd_claiming, 0);
689 prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE);
690 spin_unlock(&bdev_lock);
692 finish_wait(wq, &wait);
693 spin_lock(&bdev_lock);
702 * bd_start_claiming - start claiming a block device
703 * @bdev: block device of interest
704 * @holder: holder trying to claim @bdev
706 * @bdev is about to be opened exclusively. Check @bdev can be opened
707 * exclusively and mark that an exclusive open is in progress. Each
708 * successful call to this function must be matched with a call to
709 * either bd_claim() or bd_abort_claiming(). If this function
710 * succeeds, the matching bd_claim() is guaranteed to succeed.
716 * Pointer to the block device containing @bdev on success, ERR_PTR()
719 static struct block_device *bd_start_claiming(struct block_device *bdev,
722 struct gendisk *disk;
723 struct block_device *whole;
729 * @bdev might not have been initialized properly yet, look up
730 * and grab the outer block device the hard way.
732 disk = get_gendisk(bdev->bd_dev, &partno);
734 return ERR_PTR(-ENXIO);
736 whole = bdget_disk(disk, 0);
737 module_put(disk->fops->owner);
740 return ERR_PTR(-ENOMEM);
742 /* prepare to claim, if successful, mark claiming in progress */
743 spin_lock(&bdev_lock);
745 err = bd_prepare_to_claim(bdev, whole, holder);
747 whole->bd_claiming = holder;
748 spin_unlock(&bdev_lock);
751 spin_unlock(&bdev_lock);
757 /* releases bdev_lock */
758 static void __bd_abort_claiming(struct block_device *whole, void *holder)
760 BUG_ON(whole->bd_claiming != holder);
761 whole->bd_claiming = NULL;
762 wake_up_bit(&whole->bd_claiming, 0);
764 spin_unlock(&bdev_lock);
769 * bd_abort_claiming - abort claiming a block device
770 * @whole: whole block device returned by bd_start_claiming()
771 * @holder: holder trying to claim @bdev
773 * Abort a claiming block started by bd_start_claiming(). Note that
774 * @whole is not the block device to be claimed but the whole device
775 * returned by bd_start_claiming().
778 * Grabs and releases bdev_lock.
780 static void bd_abort_claiming(struct block_device *whole, void *holder)
782 spin_lock(&bdev_lock);
783 __bd_abort_claiming(whole, holder); /* releases bdev_lock */
787 * bd_claim - claim a block device
788 * @bdev: block device to claim
789 * @holder: holder trying to claim @bdev
791 * Try to claim @bdev which must have been opened successfully. This
792 * function may be called with or without preceding
793 * blk_start_claiming(). In the former case, this function is always
794 * successful and terminates the claiming block.
800 * 0 if successful, -EBUSY if @bdev is already claimed.
802 int bd_claim(struct block_device *bdev, void *holder)
804 struct block_device *whole = bdev->bd_contains;
809 spin_lock(&bdev_lock);
811 res = bd_prepare_to_claim(bdev, whole, holder);
813 /* note that for a whole device bd_holders
814 * will be incremented twice, and bd_holder will
815 * be set to bd_claim before being set to holder
818 whole->bd_holder = bd_claim;
820 bdev->bd_holder = holder;
823 if (whole->bd_claiming)
824 __bd_abort_claiming(whole, holder); /* releases bdev_lock */
826 spin_unlock(&bdev_lock);
830 EXPORT_SYMBOL(bd_claim);
832 void bd_release(struct block_device *bdev)
834 spin_lock(&bdev_lock);
835 if (!--bdev->bd_contains->bd_holders)
836 bdev->bd_contains->bd_holder = NULL;
837 if (!--bdev->bd_holders)
838 bdev->bd_holder = NULL;
839 spin_unlock(&bdev_lock);
842 EXPORT_SYMBOL(bd_release);
846 * Functions for bd_claim_by_kobject / bd_release_from_kobject
848 * If a kobject is passed to bd_claim_by_kobject()
849 * and the kobject has a parent directory,
850 * following symlinks are created:
851 * o from the kobject to the claimed bdev
852 * o from "holders" directory of the bdev to the parent of the kobject
853 * bd_release_from_kobject() removes these symlinks.
856 * If /dev/dm-0 maps to /dev/sda, kobject corresponding to
857 * /sys/block/dm-0/slaves is passed to bd_claim_by_kobject(), then:
858 * /sys/block/dm-0/slaves/sda --> /sys/block/sda
859 * /sys/block/sda/holders/dm-0 --> /sys/block/dm-0
862 static int add_symlink(struct kobject *from, struct kobject *to)
866 return sysfs_create_link(from, to, kobject_name(to));
869 static void del_symlink(struct kobject *from, struct kobject *to)
873 sysfs_remove_link(from, kobject_name(to));
877 * 'struct bd_holder' contains pointers to kobjects symlinked by
878 * bd_claim_by_kobject.
879 * It's connected to bd_holder_list which is protected by bdev->bd_sem.
882 struct list_head list; /* chain of holders of the bdev */
883 int count; /* references from the holder */
884 struct kobject *sdir; /* holder object, e.g. "/block/dm-0/slaves" */
885 struct kobject *hdev; /* e.g. "/block/dm-0" */
886 struct kobject *hdir; /* e.g. "/block/sda/holders" */
887 struct kobject *sdev; /* e.g. "/block/sda" */
891 * Get references of related kobjects at once.
892 * Returns 1 on success. 0 on failure.
894 * Should call bd_holder_release_dirs() after successful use.
896 static int bd_holder_grab_dirs(struct block_device *bdev,
897 struct bd_holder *bo)
902 bo->sdir = kobject_get(bo->sdir);
906 bo->hdev = kobject_get(bo->sdir->parent);
910 bo->sdev = kobject_get(&part_to_dev(bdev->bd_part)->kobj);
914 bo->hdir = kobject_get(bdev->bd_part->holder_dir);
921 kobject_put(bo->sdev);
923 kobject_put(bo->hdev);
925 kobject_put(bo->sdir);
930 /* Put references of related kobjects at once. */
931 static void bd_holder_release_dirs(struct bd_holder *bo)
933 kobject_put(bo->hdir);
934 kobject_put(bo->sdev);
935 kobject_put(bo->hdev);
936 kobject_put(bo->sdir);
939 static struct bd_holder *alloc_bd_holder(struct kobject *kobj)
941 struct bd_holder *bo;
943 bo = kzalloc(sizeof(*bo), GFP_KERNEL);
953 static void free_bd_holder(struct bd_holder *bo)
959 * find_bd_holder - find matching struct bd_holder from the block device
961 * @bdev: struct block device to be searched
962 * @bo: target struct bd_holder
964 * Returns matching entry with @bo in @bdev->bd_holder_list.
965 * If found, increment the reference count and return the pointer.
966 * If not found, returns NULL.
968 static struct bd_holder *find_bd_holder(struct block_device *bdev,
969 struct bd_holder *bo)
971 struct bd_holder *tmp;
973 list_for_each_entry(tmp, &bdev->bd_holder_list, list)
974 if (tmp->sdir == bo->sdir) {
983 * add_bd_holder - create sysfs symlinks for bd_claim() relationship
985 * @bdev: block device to be bd_claimed
986 * @bo: preallocated and initialized by alloc_bd_holder()
988 * Add @bo to @bdev->bd_holder_list, create symlinks.
990 * Returns 0 if symlinks are created.
991 * Returns -ve if something fails.
993 static int add_bd_holder(struct block_device *bdev, struct bd_holder *bo)
1000 if (!bd_holder_grab_dirs(bdev, bo))
1003 err = add_symlink(bo->sdir, bo->sdev);
1007 err = add_symlink(bo->hdir, bo->hdev);
1009 del_symlink(bo->sdir, bo->sdev);
1013 list_add_tail(&bo->list, &bdev->bd_holder_list);
1018 * del_bd_holder - delete sysfs symlinks for bd_claim() relationship
1020 * @bdev: block device to be bd_claimed
1021 * @kobj: holder's kobject
1023 * If there is matching entry with @kobj in @bdev->bd_holder_list
1024 * and no other bd_claim() from the same kobject,
1025 * remove the struct bd_holder from the list, delete symlinks for it.
1027 * Returns a pointer to the struct bd_holder when it's removed from the list
1028 * and ready to be freed.
1029 * Returns NULL if matching claim isn't found or there is other bd_claim()
1030 * by the same kobject.
1032 static struct bd_holder *del_bd_holder(struct block_device *bdev,
1033 struct kobject *kobj)
1035 struct bd_holder *bo;
1037 list_for_each_entry(bo, &bdev->bd_holder_list, list) {
1038 if (bo->sdir == kobj) {
1040 BUG_ON(bo->count < 0);
1042 list_del(&bo->list);
1043 del_symlink(bo->sdir, bo->sdev);
1044 del_symlink(bo->hdir, bo->hdev);
1045 bd_holder_release_dirs(bo);
1056 * bd_claim_by_kobject - bd_claim() with additional kobject signature
1058 * @bdev: block device to be claimed
1059 * @holder: holder's signature
1060 * @kobj: holder's kobject
1062 * Do bd_claim() and if it succeeds, create sysfs symlinks between
1063 * the bdev and the holder's kobject.
1064 * Use bd_release_from_kobject() when relesing the claimed bdev.
1066 * Returns 0 on success. (same as bd_claim())
1067 * Returns errno on failure.
1069 static int bd_claim_by_kobject(struct block_device *bdev, void *holder,
1070 struct kobject *kobj)
1073 struct bd_holder *bo, *found;
1078 bo = alloc_bd_holder(kobj);
1082 mutex_lock(&bdev->bd_mutex);
1084 err = bd_claim(bdev, holder);
1088 found = find_bd_holder(bdev, bo);
1092 err = add_bd_holder(bdev, bo);
1098 mutex_unlock(&bdev->bd_mutex);
1104 * bd_release_from_kobject - bd_release() with additional kobject signature
1106 * @bdev: block device to be released
1107 * @kobj: holder's kobject
1109 * Do bd_release() and remove sysfs symlinks created by bd_claim_by_kobject().
1111 static void bd_release_from_kobject(struct block_device *bdev,
1112 struct kobject *kobj)
1117 mutex_lock(&bdev->bd_mutex);
1119 free_bd_holder(del_bd_holder(bdev, kobj));
1120 mutex_unlock(&bdev->bd_mutex);
1124 * bd_claim_by_disk - wrapper function for bd_claim_by_kobject()
1126 * @bdev: block device to be claimed
1127 * @holder: holder's signature
1128 * @disk: holder's gendisk
1130 * Call bd_claim_by_kobject() with getting @disk->slave_dir.
1132 int bd_claim_by_disk(struct block_device *bdev, void *holder,
1133 struct gendisk *disk)
1135 return bd_claim_by_kobject(bdev, holder, kobject_get(disk->slave_dir));
1137 EXPORT_SYMBOL_GPL(bd_claim_by_disk);
1140 * bd_release_from_disk - wrapper function for bd_release_from_kobject()
1142 * @bdev: block device to be claimed
1143 * @disk: holder's gendisk
1145 * Call bd_release_from_kobject() and put @disk->slave_dir.
1147 void bd_release_from_disk(struct block_device *bdev, struct gendisk *disk)
1149 bd_release_from_kobject(bdev, disk->slave_dir);
1150 kobject_put(disk->slave_dir);
1152 EXPORT_SYMBOL_GPL(bd_release_from_disk);
1156 * Tries to open block device by device number. Use it ONLY if you
1157 * really do not have anything better - i.e. when you are behind a
1158 * truly sucky interface and all you are given is a device number. _Never_
1159 * to be used for internal purposes. If you ever need it - reconsider
1162 struct block_device *open_by_devnum(dev_t dev, fmode_t mode)
1164 struct block_device *bdev = bdget(dev);
1167 err = blkdev_get(bdev, mode);
1168 return err ? ERR_PTR(err) : bdev;
1171 EXPORT_SYMBOL(open_by_devnum);
1174 * flush_disk - invalidates all buffer-cache entries on a disk
1176 * @bdev: struct block device to be flushed
1178 * Invalidates all buffer-cache entries on a disk. It should be called
1179 * when a disk has been changed -- either by a media change or online
1182 static void flush_disk(struct block_device *bdev)
1184 if (__invalidate_device(bdev)) {
1185 char name[BDEVNAME_SIZE] = "";
1188 disk_name(bdev->bd_disk, 0, name);
1189 printk(KERN_WARNING "VFS: busy inodes on changed media or "
1190 "resized disk %s\n", name);
1195 if (disk_partitionable(bdev->bd_disk))
1196 bdev->bd_invalidated = 1;
1200 * check_disk_size_change - checks for disk size change and adjusts bdev size.
1201 * @disk: struct gendisk to check
1202 * @bdev: struct bdev to adjust.
1204 * This routine checks to see if the bdev size does not match the disk size
1205 * and adjusts it if it differs.
1207 void check_disk_size_change(struct gendisk *disk, struct block_device *bdev)
1209 loff_t disk_size, bdev_size;
1211 disk_size = (loff_t)get_capacity(disk) << 9;
1212 bdev_size = i_size_read(bdev->bd_inode);
1213 if (disk_size != bdev_size) {
1214 char name[BDEVNAME_SIZE];
1216 disk_name(disk, 0, name);
1218 "%s: detected capacity change from %lld to %lld\n",
1219 name, bdev_size, disk_size);
1220 i_size_write(bdev->bd_inode, disk_size);
1224 EXPORT_SYMBOL(check_disk_size_change);
1227 * revalidate_disk - wrapper for lower-level driver's revalidate_disk call-back
1228 * @disk: struct gendisk to be revalidated
1230 * This routine is a wrapper for lower-level driver's revalidate_disk
1231 * call-backs. It is used to do common pre and post operations needed
1232 * for all revalidate_disk operations.
1234 int revalidate_disk(struct gendisk *disk)
1236 struct block_device *bdev;
1239 if (disk->fops->revalidate_disk)
1240 ret = disk->fops->revalidate_disk(disk);
1242 bdev = bdget_disk(disk, 0);
1246 mutex_lock(&bdev->bd_mutex);
1247 check_disk_size_change(disk, bdev);
1248 mutex_unlock(&bdev->bd_mutex);
1252 EXPORT_SYMBOL(revalidate_disk);
1255 * This routine checks whether a removable media has been changed,
1256 * and invalidates all buffer-cache-entries in that case. This
1257 * is a relatively slow routine, so we have to try to minimize using
1258 * it. Thus it is called only upon a 'mount' or 'open'. This
1259 * is the best way of combining speed and utility, I think.
1260 * People changing diskettes in the middle of an operation deserve
1263 int check_disk_change(struct block_device *bdev)
1265 struct gendisk *disk = bdev->bd_disk;
1266 const struct block_device_operations *bdops = disk->fops;
1268 if (!bdops->media_changed)
1270 if (!bdops->media_changed(bdev->bd_disk))
1274 if (bdops->revalidate_disk)
1275 bdops->revalidate_disk(bdev->bd_disk);
1279 EXPORT_SYMBOL(check_disk_change);
1281 void bd_set_size(struct block_device *bdev, loff_t size)
1283 unsigned bsize = bdev_logical_block_size(bdev);
1285 bdev->bd_inode->i_size = size;
1286 while (bsize < PAGE_CACHE_SIZE) {
1291 bdev->bd_block_size = bsize;
1292 bdev->bd_inode->i_blkbits = blksize_bits(bsize);
1294 EXPORT_SYMBOL(bd_set_size);
1296 static int __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part);
1301 * mutex_lock(part->bd_mutex)
1302 * mutex_lock_nested(whole->bd_mutex, 1)
1305 static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
1307 struct gendisk *disk;
1312 if (mode & FMODE_READ)
1314 if (mode & FMODE_WRITE)
1317 * hooks: /n/, see "layering violations".
1319 ret = devcgroup_inode_permission(bdev->bd_inode, perm);
1329 disk = get_gendisk(bdev->bd_dev, &partno);
1331 goto out_unlock_kernel;
1333 mutex_lock_nested(&bdev->bd_mutex, for_part);
1334 if (!bdev->bd_openers) {
1335 bdev->bd_disk = disk;
1336 bdev->bd_contains = bdev;
1338 struct backing_dev_info *bdi;
1341 bdev->bd_part = disk_get_part(disk, partno);
1345 if (disk->fops->open) {
1346 ret = disk->fops->open(bdev, mode);
1347 if (ret == -ERESTARTSYS) {
1348 /* Lost a race with 'disk' being
1349 * deleted, try again.
1352 disk_put_part(bdev->bd_part);
1353 bdev->bd_part = NULL;
1354 module_put(disk->fops->owner);
1356 bdev->bd_disk = NULL;
1357 mutex_unlock(&bdev->bd_mutex);
1363 if (!bdev->bd_openers) {
1364 bd_set_size(bdev,(loff_t)get_capacity(disk)<<9);
1365 bdi = blk_get_backing_dev_info(bdev);
1367 bdi = &default_backing_dev_info;
1368 bdev->bd_inode->i_data.backing_dev_info = bdi;
1370 if (bdev->bd_invalidated)
1371 rescan_partitions(disk, bdev);
1373 struct block_device *whole;
1374 whole = bdget_disk(disk, 0);
1379 ret = __blkdev_get(whole, mode, 1);
1382 bdev->bd_contains = whole;
1383 bdev->bd_inode->i_data.backing_dev_info =
1384 whole->bd_inode->i_data.backing_dev_info;
1385 bdev->bd_part = disk_get_part(disk, partno);
1386 if (!(disk->flags & GENHD_FL_UP) ||
1387 !bdev->bd_part || !bdev->bd_part->nr_sects) {
1391 bd_set_size(bdev, (loff_t)bdev->bd_part->nr_sects << 9);
1394 module_put(disk->fops->owner);
1397 if (bdev->bd_contains == bdev) {
1398 if (bdev->bd_disk->fops->open) {
1399 ret = bdev->bd_disk->fops->open(bdev, mode);
1401 goto out_unlock_bdev;
1403 if (bdev->bd_invalidated)
1404 rescan_partitions(bdev->bd_disk, bdev);
1409 bdev->bd_part_count++;
1410 mutex_unlock(&bdev->bd_mutex);
1415 disk_put_part(bdev->bd_part);
1416 bdev->bd_disk = NULL;
1417 bdev->bd_part = NULL;
1418 bdev->bd_inode->i_data.backing_dev_info = &default_backing_dev_info;
1419 if (bdev != bdev->bd_contains)
1420 __blkdev_put(bdev->bd_contains, mode, 1);
1421 bdev->bd_contains = NULL;
1423 mutex_unlock(&bdev->bd_mutex);
1428 module_put(disk->fops->owner);
1435 int blkdev_get(struct block_device *bdev, fmode_t mode)
1437 return __blkdev_get(bdev, mode, 0);
1439 EXPORT_SYMBOL(blkdev_get);
1441 static int blkdev_open(struct inode * inode, struct file * filp)
1443 struct block_device *whole = NULL;
1444 struct block_device *bdev;
1448 * Preserve backwards compatibility and allow large file access
1449 * even if userspace doesn't ask for it explicitly. Some mkfs
1450 * binary needs it. We might want to drop this workaround
1451 * during an unstable branch.
1453 filp->f_flags |= O_LARGEFILE;
1455 if (filp->f_flags & O_NDELAY)
1456 filp->f_mode |= FMODE_NDELAY;
1457 if (filp->f_flags & O_EXCL)
1458 filp->f_mode |= FMODE_EXCL;
1459 if ((filp->f_flags & O_ACCMODE) == 3)
1460 filp->f_mode |= FMODE_WRITE_IOCTL;
1462 bdev = bd_acquire(inode);
1466 if (filp->f_mode & FMODE_EXCL) {
1467 whole = bd_start_claiming(bdev, filp);
1468 if (IS_ERR(whole)) {
1470 return PTR_ERR(whole);
1474 filp->f_mapping = bdev->bd_inode->i_mapping;
1476 res = blkdev_get(bdev, filp->f_mode);
1480 BUG_ON(bd_claim(bdev, filp) != 0);
1482 bd_abort_claiming(whole, filp);
1488 static int __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part)
1491 struct gendisk *disk = bdev->bd_disk;
1492 struct block_device *victim = NULL;
1494 mutex_lock_nested(&bdev->bd_mutex, for_part);
1497 bdev->bd_part_count--;
1499 if (!--bdev->bd_openers) {
1500 sync_blockdev(bdev);
1503 if (bdev->bd_contains == bdev) {
1504 if (disk->fops->release)
1505 ret = disk->fops->release(disk, mode);
1507 if (!bdev->bd_openers) {
1508 struct module *owner = disk->fops->owner;
1512 disk_put_part(bdev->bd_part);
1513 bdev->bd_part = NULL;
1514 bdev->bd_disk = NULL;
1515 bdev->bd_inode->i_data.backing_dev_info = &default_backing_dev_info;
1516 if (bdev != bdev->bd_contains)
1517 victim = bdev->bd_contains;
1518 bdev->bd_contains = NULL;
1521 mutex_unlock(&bdev->bd_mutex);
1524 __blkdev_put(victim, mode, 1);
1528 int blkdev_put(struct block_device *bdev, fmode_t mode)
1530 return __blkdev_put(bdev, mode, 0);
1532 EXPORT_SYMBOL(blkdev_put);
1534 static int blkdev_close(struct inode * inode, struct file * filp)
1536 struct block_device *bdev = I_BDEV(filp->f_mapping->host);
1537 if (bdev->bd_holder == filp)
1539 return blkdev_put(bdev, filp->f_mode);
1542 static long block_ioctl(struct file *file, unsigned cmd, unsigned long arg)
1544 struct block_device *bdev = I_BDEV(file->f_mapping->host);
1545 fmode_t mode = file->f_mode;
1548 * O_NDELAY can be altered using fcntl(.., F_SETFL, ..), so we have
1549 * to updated it before every ioctl.
1551 if (file->f_flags & O_NDELAY)
1552 mode |= FMODE_NDELAY;
1554 mode &= ~FMODE_NDELAY;
1556 return blkdev_ioctl(bdev, mode, cmd, arg);
1560 * Write data to the block device. Only intended for the block device itself
1561 * and the raw driver which basically is a fake block device.
1563 * Does not take i_mutex for the write and thus is not for general purpose
1566 ssize_t blkdev_aio_write(struct kiocb *iocb, const struct iovec *iov,
1567 unsigned long nr_segs, loff_t pos)
1569 struct file *file = iocb->ki_filp;
1572 BUG_ON(iocb->ki_pos != pos);
1574 ret = __generic_file_aio_write(iocb, iov, nr_segs, &iocb->ki_pos);
1575 if (ret > 0 || ret == -EIOCBQUEUED) {
1578 err = generic_write_sync(file, pos, ret);
1579 if (err < 0 && ret > 0)
1584 EXPORT_SYMBOL_GPL(blkdev_aio_write);
1587 * Try to release a page associated with block device when the system
1588 * is under memory pressure.
1590 static int blkdev_releasepage(struct page *page, gfp_t wait)
1592 struct super_block *super = BDEV_I(page->mapping->host)->bdev.bd_super;
1594 if (super && super->s_op->bdev_try_to_free_page)
1595 return super->s_op->bdev_try_to_free_page(super, page, wait);
1597 return try_to_free_buffers(page);
1600 static const struct address_space_operations def_blk_aops = {
1601 .readpage = blkdev_readpage,
1602 .writepage = blkdev_writepage,
1603 .sync_page = block_sync_page,
1604 .write_begin = blkdev_write_begin,
1605 .write_end = blkdev_write_end,
1606 .writepages = generic_writepages,
1607 .releasepage = blkdev_releasepage,
1608 .direct_IO = blkdev_direct_IO,
1611 const struct file_operations def_blk_fops = {
1612 .open = blkdev_open,
1613 .release = blkdev_close,
1614 .llseek = block_llseek,
1615 .read = do_sync_read,
1616 .write = do_sync_write,
1617 .aio_read = generic_file_aio_read,
1618 .aio_write = blkdev_aio_write,
1619 .mmap = generic_file_mmap,
1620 .fsync = blkdev_fsync,
1621 .unlocked_ioctl = block_ioctl,
1622 #ifdef CONFIG_COMPAT
1623 .compat_ioctl = compat_blkdev_ioctl,
1625 .splice_read = generic_file_splice_read,
1626 .splice_write = generic_file_splice_write,
1629 int ioctl_by_bdev(struct block_device *bdev, unsigned cmd, unsigned long arg)
1632 mm_segment_t old_fs = get_fs();
1634 res = blkdev_ioctl(bdev, 0, cmd, arg);
1639 EXPORT_SYMBOL(ioctl_by_bdev);
1642 * lookup_bdev - lookup a struct block_device by name
1643 * @pathname: special file representing the block device
1645 * Get a reference to the blockdevice at @pathname in the current
1646 * namespace if possible and return it. Return ERR_PTR(error)
1649 struct block_device *lookup_bdev(const char *pathname)
1651 struct block_device *bdev;
1652 struct inode *inode;
1656 if (!pathname || !*pathname)
1657 return ERR_PTR(-EINVAL);
1659 error = kern_path(pathname, LOOKUP_FOLLOW, &path);
1661 return ERR_PTR(error);
1663 inode = path.dentry->d_inode;
1665 if (!S_ISBLK(inode->i_mode))
1668 if (path.mnt->mnt_flags & MNT_NODEV)
1671 bdev = bd_acquire(inode);
1678 bdev = ERR_PTR(error);
1681 EXPORT_SYMBOL(lookup_bdev);
1684 * open_bdev_exclusive - open a block device by name and set it up for use
1686 * @path: special file representing the block device
1687 * @mode: FMODE_... combination to pass be used
1688 * @holder: owner for exclusion
1690 * Open the blockdevice described by the special file at @path, claim it
1693 struct block_device *open_bdev_exclusive(const char *path, fmode_t mode, void *holder)
1695 struct block_device *bdev, *whole;
1698 bdev = lookup_bdev(path);
1702 whole = bd_start_claiming(bdev, holder);
1703 if (IS_ERR(whole)) {
1708 error = blkdev_get(bdev, mode);
1710 goto out_abort_claiming;
1713 if ((mode & FMODE_WRITE) && bdev_read_only(bdev))
1714 goto out_blkdev_put;
1716 BUG_ON(bd_claim(bdev, holder) != 0);
1720 blkdev_put(bdev, mode);
1722 bd_abort_claiming(whole, holder);
1723 return ERR_PTR(error);
1726 EXPORT_SYMBOL(open_bdev_exclusive);
1729 * close_bdev_exclusive - close a blockdevice opened by open_bdev_exclusive()
1731 * @bdev: blockdevice to close
1732 * @mode: mode, must match that used to open.
1734 * This is the counterpart to open_bdev_exclusive().
1736 void close_bdev_exclusive(struct block_device *bdev, fmode_t mode)
1739 blkdev_put(bdev, mode);
1742 EXPORT_SYMBOL(close_bdev_exclusive);
1744 int __invalidate_device(struct block_device *bdev)
1746 struct super_block *sb = get_super(bdev);
1751 * no need to lock the super, get_super holds the
1752 * read mutex so the filesystem cannot go away
1753 * under us (->put_super runs with the write lock
1756 shrink_dcache_sb(sb);
1757 res = invalidate_inodes(sb);
1760 invalidate_bdev(bdev);
1763 EXPORT_SYMBOL(__invalidate_device);