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(rw, iocb, inode, I_BDEV(inode),
176 iov, offset, nr_segs, blkdev_get_blocks, NULL);
179 int __sync_blockdev(struct block_device *bdev, int wait)
184 return filemap_flush(bdev->bd_inode->i_mapping);
185 return filemap_write_and_wait(bdev->bd_inode->i_mapping);
189 * Write out and wait upon all the dirty data associated with a block
190 * device via its mapping. Does not take the superblock lock.
192 int sync_blockdev(struct block_device *bdev)
194 return __sync_blockdev(bdev, 1);
196 EXPORT_SYMBOL(sync_blockdev);
199 * Write out and wait upon all dirty data associated with this
200 * device. Filesystem data as well as the underlying block
201 * device. Takes the superblock lock.
203 int fsync_bdev(struct block_device *bdev)
205 struct super_block *sb = get_super(bdev);
207 int res = sync_filesystem(sb);
211 return sync_blockdev(bdev);
213 EXPORT_SYMBOL(fsync_bdev);
216 * freeze_bdev -- lock a filesystem and force it into a consistent state
217 * @bdev: blockdevice to lock
219 * If a superblock is found on this device, we take the s_umount semaphore
220 * on it to make sure nobody unmounts until the snapshot creation is done.
221 * The reference counter (bd_fsfreeze_count) guarantees that only the last
222 * unfreeze process can unfreeze the frozen filesystem actually when multiple
223 * freeze requests arrive simultaneously. It counts up in freeze_bdev() and
224 * count down in thaw_bdev(). When it becomes 0, thaw_bdev() will unfreeze
227 struct super_block *freeze_bdev(struct block_device *bdev)
229 struct super_block *sb;
232 mutex_lock(&bdev->bd_fsfreeze_mutex);
233 if (++bdev->bd_fsfreeze_count > 1) {
235 * We don't even need to grab a reference - the first call
236 * to freeze_bdev grab an active reference and only the last
237 * thaw_bdev drops it.
239 sb = get_super(bdev);
241 mutex_unlock(&bdev->bd_fsfreeze_mutex);
245 sb = get_active_super(bdev);
248 if (sb->s_flags & MS_RDONLY) {
249 sb->s_frozen = SB_FREEZE_TRANS;
250 up_write(&sb->s_umount);
251 mutex_unlock(&bdev->bd_fsfreeze_mutex);
255 sb->s_frozen = SB_FREEZE_WRITE;
260 sb->s_frozen = SB_FREEZE_TRANS;
263 sync_blockdev(sb->s_bdev);
265 if (sb->s_op->freeze_fs) {
266 error = sb->s_op->freeze_fs(sb);
269 "VFS:Filesystem freeze failed\n");
270 sb->s_frozen = SB_UNFROZEN;
271 deactivate_locked_super(sb);
272 bdev->bd_fsfreeze_count--;
273 mutex_unlock(&bdev->bd_fsfreeze_mutex);
274 return ERR_PTR(error);
277 up_write(&sb->s_umount);
281 mutex_unlock(&bdev->bd_fsfreeze_mutex);
282 return sb; /* thaw_bdev releases s->s_umount */
284 EXPORT_SYMBOL(freeze_bdev);
287 * thaw_bdev -- unlock filesystem
288 * @bdev: blockdevice to unlock
289 * @sb: associated superblock
291 * Unlocks the filesystem and marks it writeable again after freeze_bdev().
293 int thaw_bdev(struct block_device *bdev, struct super_block *sb)
297 mutex_lock(&bdev->bd_fsfreeze_mutex);
298 if (!bdev->bd_fsfreeze_count)
302 if (--bdev->bd_fsfreeze_count > 0)
308 BUG_ON(sb->s_bdev != bdev);
309 down_write(&sb->s_umount);
310 if (sb->s_flags & MS_RDONLY)
313 if (sb->s_op->unfreeze_fs) {
314 error = sb->s_op->unfreeze_fs(sb);
317 "VFS:Filesystem thaw failed\n");
318 sb->s_frozen = SB_FREEZE_TRANS;
319 bdev->bd_fsfreeze_count++;
320 mutex_unlock(&bdev->bd_fsfreeze_mutex);
326 sb->s_frozen = SB_UNFROZEN;
328 wake_up(&sb->s_wait_unfrozen);
331 deactivate_locked_super(sb);
333 mutex_unlock(&bdev->bd_fsfreeze_mutex);
336 EXPORT_SYMBOL(thaw_bdev);
338 static int blkdev_writepage(struct page *page, struct writeback_control *wbc)
340 return block_write_full_page(page, blkdev_get_block, wbc);
343 static int blkdev_readpage(struct file * file, struct page * page)
345 return block_read_full_page(page, blkdev_get_block);
348 static int blkdev_write_begin(struct file *file, struct address_space *mapping,
349 loff_t pos, unsigned len, unsigned flags,
350 struct page **pagep, void **fsdata)
353 return block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
357 static int blkdev_write_end(struct file *file, struct address_space *mapping,
358 loff_t pos, unsigned len, unsigned copied,
359 struct page *page, void *fsdata)
362 ret = block_write_end(file, mapping, pos, len, copied, page, fsdata);
365 page_cache_release(page);
372 * for a block special file file->f_path.dentry->d_inode->i_size is zero
373 * so we compute the size by hand (just as in block_read/write above)
375 static loff_t block_llseek(struct file *file, loff_t offset, int origin)
377 struct inode *bd_inode = file->f_mapping->host;
381 mutex_lock(&bd_inode->i_mutex);
382 size = i_size_read(bd_inode);
389 offset += file->f_pos;
392 if (offset >= 0 && offset <= size) {
393 if (offset != file->f_pos) {
394 file->f_pos = offset;
398 mutex_unlock(&bd_inode->i_mutex);
403 * Filp is never NULL; the only case when ->fsync() is called with
404 * NULL first argument is nfsd_sync_dir() and that's not a directory.
407 int blkdev_fsync(struct file *filp, struct dentry *dentry, int datasync)
409 struct block_device *bdev = I_BDEV(filp->f_mapping->host);
412 error = sync_blockdev(bdev);
416 error = blkdev_issue_flush(bdev, NULL);
417 if (error == -EOPNOTSUPP)
421 EXPORT_SYMBOL(blkdev_fsync);
427 static __cacheline_aligned_in_smp DEFINE_SPINLOCK(bdev_lock);
428 static struct kmem_cache * bdev_cachep __read_mostly;
430 static struct inode *bdev_alloc_inode(struct super_block *sb)
432 struct bdev_inode *ei = kmem_cache_alloc(bdev_cachep, GFP_KERNEL);
435 return &ei->vfs_inode;
438 static void bdev_destroy_inode(struct inode *inode)
440 struct bdev_inode *bdi = BDEV_I(inode);
442 kmem_cache_free(bdev_cachep, bdi);
445 static void init_once(void *foo)
447 struct bdev_inode *ei = (struct bdev_inode *) foo;
448 struct block_device *bdev = &ei->bdev;
450 memset(bdev, 0, sizeof(*bdev));
451 mutex_init(&bdev->bd_mutex);
452 INIT_LIST_HEAD(&bdev->bd_inodes);
453 INIT_LIST_HEAD(&bdev->bd_list);
455 INIT_LIST_HEAD(&bdev->bd_holder_list);
457 inode_init_once(&ei->vfs_inode);
458 /* Initialize mutex for freeze. */
459 mutex_init(&bdev->bd_fsfreeze_mutex);
462 static inline void __bd_forget(struct inode *inode)
464 list_del_init(&inode->i_devices);
465 inode->i_bdev = NULL;
466 inode->i_mapping = &inode->i_data;
469 static void bdev_clear_inode(struct inode *inode)
471 struct block_device *bdev = &BDEV_I(inode)->bdev;
473 spin_lock(&bdev_lock);
474 while ( (p = bdev->bd_inodes.next) != &bdev->bd_inodes ) {
475 __bd_forget(list_entry(p, struct inode, i_devices));
477 list_del_init(&bdev->bd_list);
478 spin_unlock(&bdev_lock);
481 static const struct super_operations bdev_sops = {
482 .statfs = simple_statfs,
483 .alloc_inode = bdev_alloc_inode,
484 .destroy_inode = bdev_destroy_inode,
485 .drop_inode = generic_delete_inode,
486 .clear_inode = bdev_clear_inode,
489 static int bd_get_sb(struct file_system_type *fs_type,
490 int flags, const char *dev_name, void *data, struct vfsmount *mnt)
492 return get_sb_pseudo(fs_type, "bdev:", &bdev_sops, 0x62646576, mnt);
495 static struct file_system_type bd_type = {
498 .kill_sb = kill_anon_super,
501 struct super_block *blockdev_superblock __read_mostly;
503 void __init bdev_cache_init(void)
506 struct vfsmount *bd_mnt;
508 bdev_cachep = kmem_cache_create("bdev_cache", sizeof(struct bdev_inode),
509 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
510 SLAB_MEM_SPREAD|SLAB_PANIC),
512 err = register_filesystem(&bd_type);
514 panic("Cannot register bdev pseudo-fs");
515 bd_mnt = kern_mount(&bd_type);
517 panic("Cannot create bdev pseudo-fs");
519 * This vfsmount structure is only used to obtain the
520 * blockdev_superblock, so tell kmemleak not to report it.
522 kmemleak_not_leak(bd_mnt);
523 blockdev_superblock = bd_mnt->mnt_sb; /* For writeback */
527 * Most likely _very_ bad one - but then it's hardly critical for small
528 * /dev and can be fixed when somebody will need really large one.
529 * Keep in mind that it will be fed through icache hash function too.
531 static inline unsigned long hash(dev_t dev)
533 return MAJOR(dev)+MINOR(dev);
536 static int bdev_test(struct inode *inode, void *data)
538 return BDEV_I(inode)->bdev.bd_dev == *(dev_t *)data;
541 static int bdev_set(struct inode *inode, void *data)
543 BDEV_I(inode)->bdev.bd_dev = *(dev_t *)data;
547 static LIST_HEAD(all_bdevs);
549 struct block_device *bdget(dev_t dev)
551 struct block_device *bdev;
554 inode = iget5_locked(blockdev_superblock, hash(dev),
555 bdev_test, bdev_set, &dev);
560 bdev = &BDEV_I(inode)->bdev;
562 if (inode->i_state & I_NEW) {
563 bdev->bd_contains = NULL;
564 bdev->bd_inode = inode;
565 bdev->bd_block_size = (1 << inode->i_blkbits);
566 bdev->bd_part_count = 0;
567 bdev->bd_invalidated = 0;
568 inode->i_mode = S_IFBLK;
570 inode->i_bdev = bdev;
571 inode->i_data.a_ops = &def_blk_aops;
572 mapping_set_gfp_mask(&inode->i_data, GFP_USER);
573 inode->i_data.backing_dev_info = &default_backing_dev_info;
574 spin_lock(&bdev_lock);
575 list_add(&bdev->bd_list, &all_bdevs);
576 spin_unlock(&bdev_lock);
577 unlock_new_inode(inode);
582 EXPORT_SYMBOL(bdget);
585 * bdgrab -- Grab a reference to an already referenced block device
586 * @bdev: Block device to grab a reference to.
588 struct block_device *bdgrab(struct block_device *bdev)
590 atomic_inc(&bdev->bd_inode->i_count);
594 long nr_blockdev_pages(void)
596 struct block_device *bdev;
598 spin_lock(&bdev_lock);
599 list_for_each_entry(bdev, &all_bdevs, bd_list) {
600 ret += bdev->bd_inode->i_mapping->nrpages;
602 spin_unlock(&bdev_lock);
606 void bdput(struct block_device *bdev)
608 iput(bdev->bd_inode);
611 EXPORT_SYMBOL(bdput);
613 static struct block_device *bd_acquire(struct inode *inode)
615 struct block_device *bdev;
617 spin_lock(&bdev_lock);
618 bdev = inode->i_bdev;
620 atomic_inc(&bdev->bd_inode->i_count);
621 spin_unlock(&bdev_lock);
624 spin_unlock(&bdev_lock);
626 bdev = bdget(inode->i_rdev);
628 spin_lock(&bdev_lock);
629 if (!inode->i_bdev) {
631 * We take an additional bd_inode->i_count for inode,
632 * and it's released in clear_inode() of inode.
633 * So, we can access it via ->i_mapping always
636 atomic_inc(&bdev->bd_inode->i_count);
637 inode->i_bdev = bdev;
638 inode->i_mapping = bdev->bd_inode->i_mapping;
639 list_add(&inode->i_devices, &bdev->bd_inodes);
641 spin_unlock(&bdev_lock);
646 /* Call when you free inode */
648 void bd_forget(struct inode *inode)
650 struct block_device *bdev = NULL;
652 spin_lock(&bdev_lock);
654 if (!sb_is_blkdev_sb(inode->i_sb))
655 bdev = inode->i_bdev;
658 spin_unlock(&bdev_lock);
661 iput(bdev->bd_inode);
665 * bd_may_claim - test whether a block device can be claimed
666 * @bdev: block device of interest
667 * @whole: whole block device containing @bdev, may equal @bdev
668 * @holder: holder trying to claim @bdev
670 * Test whther @bdev can be claimed by @holder.
673 * spin_lock(&bdev_lock).
676 * %true if @bdev can be claimed, %false otherwise.
678 static bool bd_may_claim(struct block_device *bdev, struct block_device *whole,
681 if (bdev->bd_holder == holder)
682 return true; /* already a holder */
683 else if (bdev->bd_holder != NULL)
684 return false; /* held by someone else */
685 else if (bdev->bd_contains == bdev)
686 return true; /* is a whole device which isn't held */
688 else if (whole->bd_holder == bd_claim)
689 return true; /* is a partition of a device that is being partitioned */
690 else if (whole->bd_holder != NULL)
691 return false; /* is a partition of a held device */
693 return true; /* is a partition of an un-held device */
697 * bd_claim - claim a block device
698 * @bdev: block device to claim
699 * @holder: holder trying to claim @bdev
701 * Try to claim @bdev.
704 * 0 if successful, -EBUSY if @bdev is already claimed.
706 int bd_claim(struct block_device *bdev, void *holder)
708 struct block_device *whole = bdev->bd_contains;
711 spin_lock(&bdev_lock);
713 if (bd_may_claim(bdev, whole, holder)) {
714 /* note that for a whole device bd_holders
715 * will be incremented twice, and bd_holder will
716 * be set to bd_claim before being set to holder
719 whole->bd_holder = bd_claim;
721 bdev->bd_holder = holder;
725 spin_unlock(&bdev_lock);
728 EXPORT_SYMBOL(bd_claim);
730 void bd_release(struct block_device *bdev)
732 spin_lock(&bdev_lock);
733 if (!--bdev->bd_contains->bd_holders)
734 bdev->bd_contains->bd_holder = NULL;
735 if (!--bdev->bd_holders)
736 bdev->bd_holder = NULL;
737 spin_unlock(&bdev_lock);
740 EXPORT_SYMBOL(bd_release);
744 * Functions for bd_claim_by_kobject / bd_release_from_kobject
746 * If a kobject is passed to bd_claim_by_kobject()
747 * and the kobject has a parent directory,
748 * following symlinks are created:
749 * o from the kobject to the claimed bdev
750 * o from "holders" directory of the bdev to the parent of the kobject
751 * bd_release_from_kobject() removes these symlinks.
754 * If /dev/dm-0 maps to /dev/sda, kobject corresponding to
755 * /sys/block/dm-0/slaves is passed to bd_claim_by_kobject(), then:
756 * /sys/block/dm-0/slaves/sda --> /sys/block/sda
757 * /sys/block/sda/holders/dm-0 --> /sys/block/dm-0
760 static int add_symlink(struct kobject *from, struct kobject *to)
764 return sysfs_create_link(from, to, kobject_name(to));
767 static void del_symlink(struct kobject *from, struct kobject *to)
771 sysfs_remove_link(from, kobject_name(to));
775 * 'struct bd_holder' contains pointers to kobjects symlinked by
776 * bd_claim_by_kobject.
777 * It's connected to bd_holder_list which is protected by bdev->bd_sem.
780 struct list_head list; /* chain of holders of the bdev */
781 int count; /* references from the holder */
782 struct kobject *sdir; /* holder object, e.g. "/block/dm-0/slaves" */
783 struct kobject *hdev; /* e.g. "/block/dm-0" */
784 struct kobject *hdir; /* e.g. "/block/sda/holders" */
785 struct kobject *sdev; /* e.g. "/block/sda" */
789 * Get references of related kobjects at once.
790 * Returns 1 on success. 0 on failure.
792 * Should call bd_holder_release_dirs() after successful use.
794 static int bd_holder_grab_dirs(struct block_device *bdev,
795 struct bd_holder *bo)
800 bo->sdir = kobject_get(bo->sdir);
804 bo->hdev = kobject_get(bo->sdir->parent);
808 bo->sdev = kobject_get(&part_to_dev(bdev->bd_part)->kobj);
812 bo->hdir = kobject_get(bdev->bd_part->holder_dir);
819 kobject_put(bo->sdev);
821 kobject_put(bo->hdev);
823 kobject_put(bo->sdir);
828 /* Put references of related kobjects at once. */
829 static void bd_holder_release_dirs(struct bd_holder *bo)
831 kobject_put(bo->hdir);
832 kobject_put(bo->sdev);
833 kobject_put(bo->hdev);
834 kobject_put(bo->sdir);
837 static struct bd_holder *alloc_bd_holder(struct kobject *kobj)
839 struct bd_holder *bo;
841 bo = kzalloc(sizeof(*bo), GFP_KERNEL);
851 static void free_bd_holder(struct bd_holder *bo)
857 * find_bd_holder - find matching struct bd_holder from the block device
859 * @bdev: struct block device to be searched
860 * @bo: target struct bd_holder
862 * Returns matching entry with @bo in @bdev->bd_holder_list.
863 * If found, increment the reference count and return the pointer.
864 * If not found, returns NULL.
866 static struct bd_holder *find_bd_holder(struct block_device *bdev,
867 struct bd_holder *bo)
869 struct bd_holder *tmp;
871 list_for_each_entry(tmp, &bdev->bd_holder_list, list)
872 if (tmp->sdir == bo->sdir) {
881 * add_bd_holder - create sysfs symlinks for bd_claim() relationship
883 * @bdev: block device to be bd_claimed
884 * @bo: preallocated and initialized by alloc_bd_holder()
886 * Add @bo to @bdev->bd_holder_list, create symlinks.
888 * Returns 0 if symlinks are created.
889 * Returns -ve if something fails.
891 static int add_bd_holder(struct block_device *bdev, struct bd_holder *bo)
898 if (!bd_holder_grab_dirs(bdev, bo))
901 err = add_symlink(bo->sdir, bo->sdev);
905 err = add_symlink(bo->hdir, bo->hdev);
907 del_symlink(bo->sdir, bo->sdev);
911 list_add_tail(&bo->list, &bdev->bd_holder_list);
916 * del_bd_holder - delete sysfs symlinks for bd_claim() relationship
918 * @bdev: block device to be bd_claimed
919 * @kobj: holder's kobject
921 * If there is matching entry with @kobj in @bdev->bd_holder_list
922 * and no other bd_claim() from the same kobject,
923 * remove the struct bd_holder from the list, delete symlinks for it.
925 * Returns a pointer to the struct bd_holder when it's removed from the list
926 * and ready to be freed.
927 * Returns NULL if matching claim isn't found or there is other bd_claim()
928 * by the same kobject.
930 static struct bd_holder *del_bd_holder(struct block_device *bdev,
931 struct kobject *kobj)
933 struct bd_holder *bo;
935 list_for_each_entry(bo, &bdev->bd_holder_list, list) {
936 if (bo->sdir == kobj) {
938 BUG_ON(bo->count < 0);
941 del_symlink(bo->sdir, bo->sdev);
942 del_symlink(bo->hdir, bo->hdev);
943 bd_holder_release_dirs(bo);
954 * bd_claim_by_kobject - bd_claim() with additional kobject signature
956 * @bdev: block device to be claimed
957 * @holder: holder's signature
958 * @kobj: holder's kobject
960 * Do bd_claim() and if it succeeds, create sysfs symlinks between
961 * the bdev and the holder's kobject.
962 * Use bd_release_from_kobject() when relesing the claimed bdev.
964 * Returns 0 on success. (same as bd_claim())
965 * Returns errno on failure.
967 static int bd_claim_by_kobject(struct block_device *bdev, void *holder,
968 struct kobject *kobj)
971 struct bd_holder *bo, *found;
976 bo = alloc_bd_holder(kobj);
980 mutex_lock(&bdev->bd_mutex);
982 err = bd_claim(bdev, holder);
986 found = find_bd_holder(bdev, bo);
990 err = add_bd_holder(bdev, bo);
996 mutex_unlock(&bdev->bd_mutex);
1002 * bd_release_from_kobject - bd_release() with additional kobject signature
1004 * @bdev: block device to be released
1005 * @kobj: holder's kobject
1007 * Do bd_release() and remove sysfs symlinks created by bd_claim_by_kobject().
1009 static void bd_release_from_kobject(struct block_device *bdev,
1010 struct kobject *kobj)
1015 mutex_lock(&bdev->bd_mutex);
1017 free_bd_holder(del_bd_holder(bdev, kobj));
1018 mutex_unlock(&bdev->bd_mutex);
1022 * bd_claim_by_disk - wrapper function for bd_claim_by_kobject()
1024 * @bdev: block device to be claimed
1025 * @holder: holder's signature
1026 * @disk: holder's gendisk
1028 * Call bd_claim_by_kobject() with getting @disk->slave_dir.
1030 int bd_claim_by_disk(struct block_device *bdev, void *holder,
1031 struct gendisk *disk)
1033 return bd_claim_by_kobject(bdev, holder, kobject_get(disk->slave_dir));
1035 EXPORT_SYMBOL_GPL(bd_claim_by_disk);
1038 * bd_release_from_disk - wrapper function for bd_release_from_kobject()
1040 * @bdev: block device to be claimed
1041 * @disk: holder's gendisk
1043 * Call bd_release_from_kobject() and put @disk->slave_dir.
1045 void bd_release_from_disk(struct block_device *bdev, struct gendisk *disk)
1047 bd_release_from_kobject(bdev, disk->slave_dir);
1048 kobject_put(disk->slave_dir);
1050 EXPORT_SYMBOL_GPL(bd_release_from_disk);
1054 * Tries to open block device by device number. Use it ONLY if you
1055 * really do not have anything better - i.e. when you are behind a
1056 * truly sucky interface and all you are given is a device number. _Never_
1057 * to be used for internal purposes. If you ever need it - reconsider
1060 struct block_device *open_by_devnum(dev_t dev, fmode_t mode)
1062 struct block_device *bdev = bdget(dev);
1065 err = blkdev_get(bdev, mode);
1066 return err ? ERR_PTR(err) : bdev;
1069 EXPORT_SYMBOL(open_by_devnum);
1072 * flush_disk - invalidates all buffer-cache entries on a disk
1074 * @bdev: struct block device to be flushed
1076 * Invalidates all buffer-cache entries on a disk. It should be called
1077 * when a disk has been changed -- either by a media change or online
1080 static void flush_disk(struct block_device *bdev)
1082 if (__invalidate_device(bdev)) {
1083 char name[BDEVNAME_SIZE] = "";
1086 disk_name(bdev->bd_disk, 0, name);
1087 printk(KERN_WARNING "VFS: busy inodes on changed media or "
1088 "resized disk %s\n", name);
1093 if (disk_partitionable(bdev->bd_disk))
1094 bdev->bd_invalidated = 1;
1098 * check_disk_size_change - checks for disk size change and adjusts bdev size.
1099 * @disk: struct gendisk to check
1100 * @bdev: struct bdev to adjust.
1102 * This routine checks to see if the bdev size does not match the disk size
1103 * and adjusts it if it differs.
1105 void check_disk_size_change(struct gendisk *disk, struct block_device *bdev)
1107 loff_t disk_size, bdev_size;
1109 disk_size = (loff_t)get_capacity(disk) << 9;
1110 bdev_size = i_size_read(bdev->bd_inode);
1111 if (disk_size != bdev_size) {
1112 char name[BDEVNAME_SIZE];
1114 disk_name(disk, 0, name);
1116 "%s: detected capacity change from %lld to %lld\n",
1117 name, bdev_size, disk_size);
1118 i_size_write(bdev->bd_inode, disk_size);
1122 EXPORT_SYMBOL(check_disk_size_change);
1125 * revalidate_disk - wrapper for lower-level driver's revalidate_disk call-back
1126 * @disk: struct gendisk to be revalidated
1128 * This routine is a wrapper for lower-level driver's revalidate_disk
1129 * call-backs. It is used to do common pre and post operations needed
1130 * for all revalidate_disk operations.
1132 int revalidate_disk(struct gendisk *disk)
1134 struct block_device *bdev;
1137 if (disk->fops->revalidate_disk)
1138 ret = disk->fops->revalidate_disk(disk);
1140 bdev = bdget_disk(disk, 0);
1144 mutex_lock(&bdev->bd_mutex);
1145 check_disk_size_change(disk, bdev);
1146 mutex_unlock(&bdev->bd_mutex);
1150 EXPORT_SYMBOL(revalidate_disk);
1153 * This routine checks whether a removable media has been changed,
1154 * and invalidates all buffer-cache-entries in that case. This
1155 * is a relatively slow routine, so we have to try to minimize using
1156 * it. Thus it is called only upon a 'mount' or 'open'. This
1157 * is the best way of combining speed and utility, I think.
1158 * People changing diskettes in the middle of an operation deserve
1161 int check_disk_change(struct block_device *bdev)
1163 struct gendisk *disk = bdev->bd_disk;
1164 const struct block_device_operations *bdops = disk->fops;
1166 if (!bdops->media_changed)
1168 if (!bdops->media_changed(bdev->bd_disk))
1172 if (bdops->revalidate_disk)
1173 bdops->revalidate_disk(bdev->bd_disk);
1177 EXPORT_SYMBOL(check_disk_change);
1179 void bd_set_size(struct block_device *bdev, loff_t size)
1181 unsigned bsize = bdev_logical_block_size(bdev);
1183 bdev->bd_inode->i_size = size;
1184 while (bsize < PAGE_CACHE_SIZE) {
1189 bdev->bd_block_size = bsize;
1190 bdev->bd_inode->i_blkbits = blksize_bits(bsize);
1192 EXPORT_SYMBOL(bd_set_size);
1194 static int __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part);
1199 * mutex_lock(part->bd_mutex)
1200 * mutex_lock_nested(whole->bd_mutex, 1)
1203 static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
1205 struct gendisk *disk;
1210 if (mode & FMODE_READ)
1212 if (mode & FMODE_WRITE)
1215 * hooks: /n/, see "layering violations".
1217 ret = devcgroup_inode_permission(bdev->bd_inode, perm);
1227 disk = get_gendisk(bdev->bd_dev, &partno);
1229 goto out_unlock_kernel;
1231 mutex_lock_nested(&bdev->bd_mutex, for_part);
1232 if (!bdev->bd_openers) {
1233 bdev->bd_disk = disk;
1234 bdev->bd_contains = bdev;
1236 struct backing_dev_info *bdi;
1239 bdev->bd_part = disk_get_part(disk, partno);
1243 if (disk->fops->open) {
1244 ret = disk->fops->open(bdev, mode);
1245 if (ret == -ERESTARTSYS) {
1246 /* Lost a race with 'disk' being
1247 * deleted, try again.
1250 disk_put_part(bdev->bd_part);
1251 bdev->bd_part = NULL;
1252 module_put(disk->fops->owner);
1254 bdev->bd_disk = NULL;
1255 mutex_unlock(&bdev->bd_mutex);
1261 if (!bdev->bd_openers) {
1262 bd_set_size(bdev,(loff_t)get_capacity(disk)<<9);
1263 bdi = blk_get_backing_dev_info(bdev);
1265 bdi = &default_backing_dev_info;
1266 bdev->bd_inode->i_data.backing_dev_info = bdi;
1268 if (bdev->bd_invalidated)
1269 rescan_partitions(disk, bdev);
1271 struct block_device *whole;
1272 whole = bdget_disk(disk, 0);
1277 ret = __blkdev_get(whole, mode, 1);
1280 bdev->bd_contains = whole;
1281 bdev->bd_inode->i_data.backing_dev_info =
1282 whole->bd_inode->i_data.backing_dev_info;
1283 bdev->bd_part = disk_get_part(disk, partno);
1284 if (!(disk->flags & GENHD_FL_UP) ||
1285 !bdev->bd_part || !bdev->bd_part->nr_sects) {
1289 bd_set_size(bdev, (loff_t)bdev->bd_part->nr_sects << 9);
1292 module_put(disk->fops->owner);
1295 if (bdev->bd_contains == bdev) {
1296 if (bdev->bd_disk->fops->open) {
1297 ret = bdev->bd_disk->fops->open(bdev, mode);
1299 goto out_unlock_bdev;
1301 if (bdev->bd_invalidated)
1302 rescan_partitions(bdev->bd_disk, bdev);
1307 bdev->bd_part_count++;
1308 mutex_unlock(&bdev->bd_mutex);
1313 disk_put_part(bdev->bd_part);
1314 bdev->bd_disk = NULL;
1315 bdev->bd_part = NULL;
1316 bdev->bd_inode->i_data.backing_dev_info = &default_backing_dev_info;
1317 if (bdev != bdev->bd_contains)
1318 __blkdev_put(bdev->bd_contains, mode, 1);
1319 bdev->bd_contains = NULL;
1321 mutex_unlock(&bdev->bd_mutex);
1326 module_put(disk->fops->owner);
1333 int blkdev_get(struct block_device *bdev, fmode_t mode)
1335 return __blkdev_get(bdev, mode, 0);
1337 EXPORT_SYMBOL(blkdev_get);
1339 static int blkdev_open(struct inode * inode, struct file * filp)
1341 struct block_device *bdev;
1345 * Preserve backwards compatibility and allow large file access
1346 * even if userspace doesn't ask for it explicitly. Some mkfs
1347 * binary needs it. We might want to drop this workaround
1348 * during an unstable branch.
1350 filp->f_flags |= O_LARGEFILE;
1352 if (filp->f_flags & O_NDELAY)
1353 filp->f_mode |= FMODE_NDELAY;
1354 if (filp->f_flags & O_EXCL)
1355 filp->f_mode |= FMODE_EXCL;
1356 if ((filp->f_flags & O_ACCMODE) == 3)
1357 filp->f_mode |= FMODE_WRITE_IOCTL;
1359 bdev = bd_acquire(inode);
1363 filp->f_mapping = bdev->bd_inode->i_mapping;
1365 res = blkdev_get(bdev, filp->f_mode);
1369 if (filp->f_mode & FMODE_EXCL) {
1370 res = bd_claim(bdev, filp);
1372 goto out_blkdev_put;
1378 blkdev_put(bdev, filp->f_mode);
1382 static int __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part)
1385 struct gendisk *disk = bdev->bd_disk;
1386 struct block_device *victim = NULL;
1388 mutex_lock_nested(&bdev->bd_mutex, for_part);
1391 bdev->bd_part_count--;
1393 if (!--bdev->bd_openers) {
1394 sync_blockdev(bdev);
1397 if (bdev->bd_contains == bdev) {
1398 if (disk->fops->release)
1399 ret = disk->fops->release(disk, mode);
1401 if (!bdev->bd_openers) {
1402 struct module *owner = disk->fops->owner;
1406 disk_put_part(bdev->bd_part);
1407 bdev->bd_part = NULL;
1408 bdev->bd_disk = NULL;
1409 bdev->bd_inode->i_data.backing_dev_info = &default_backing_dev_info;
1410 if (bdev != bdev->bd_contains)
1411 victim = bdev->bd_contains;
1412 bdev->bd_contains = NULL;
1415 mutex_unlock(&bdev->bd_mutex);
1418 __blkdev_put(victim, mode, 1);
1422 int blkdev_put(struct block_device *bdev, fmode_t mode)
1424 return __blkdev_put(bdev, mode, 0);
1426 EXPORT_SYMBOL(blkdev_put);
1428 static int blkdev_close(struct inode * inode, struct file * filp)
1430 struct block_device *bdev = I_BDEV(filp->f_mapping->host);
1431 if (bdev->bd_holder == filp)
1433 return blkdev_put(bdev, filp->f_mode);
1436 static long block_ioctl(struct file *file, unsigned cmd, unsigned long arg)
1438 struct block_device *bdev = I_BDEV(file->f_mapping->host);
1439 fmode_t mode = file->f_mode;
1442 * O_NDELAY can be altered using fcntl(.., F_SETFL, ..), so we have
1443 * to updated it before every ioctl.
1445 if (file->f_flags & O_NDELAY)
1446 mode |= FMODE_NDELAY;
1448 mode &= ~FMODE_NDELAY;
1450 return blkdev_ioctl(bdev, mode, cmd, arg);
1454 * Write data to the block device. Only intended for the block device itself
1455 * and the raw driver which basically is a fake block device.
1457 * Does not take i_mutex for the write and thus is not for general purpose
1460 ssize_t blkdev_aio_write(struct kiocb *iocb, const struct iovec *iov,
1461 unsigned long nr_segs, loff_t pos)
1463 struct file *file = iocb->ki_filp;
1466 BUG_ON(iocb->ki_pos != pos);
1468 ret = __generic_file_aio_write(iocb, iov, nr_segs, &iocb->ki_pos);
1469 if (ret > 0 || ret == -EIOCBQUEUED) {
1472 err = generic_write_sync(file, pos, ret);
1473 if (err < 0 && ret > 0)
1478 EXPORT_SYMBOL_GPL(blkdev_aio_write);
1481 * Try to release a page associated with block device when the system
1482 * is under memory pressure.
1484 static int blkdev_releasepage(struct page *page, gfp_t wait)
1486 struct super_block *super = BDEV_I(page->mapping->host)->bdev.bd_super;
1488 if (super && super->s_op->bdev_try_to_free_page)
1489 return super->s_op->bdev_try_to_free_page(super, page, wait);
1491 return try_to_free_buffers(page);
1494 static const struct address_space_operations def_blk_aops = {
1495 .readpage = blkdev_readpage,
1496 .writepage = blkdev_writepage,
1497 .sync_page = block_sync_page,
1498 .write_begin = blkdev_write_begin,
1499 .write_end = blkdev_write_end,
1500 .writepages = generic_writepages,
1501 .releasepage = blkdev_releasepage,
1502 .direct_IO = blkdev_direct_IO,
1505 const struct file_operations def_blk_fops = {
1506 .open = blkdev_open,
1507 .release = blkdev_close,
1508 .llseek = block_llseek,
1509 .read = do_sync_read,
1510 .write = do_sync_write,
1511 .aio_read = generic_file_aio_read,
1512 .aio_write = blkdev_aio_write,
1513 .mmap = generic_file_mmap,
1514 .fsync = blkdev_fsync,
1515 .unlocked_ioctl = block_ioctl,
1516 #ifdef CONFIG_COMPAT
1517 .compat_ioctl = compat_blkdev_ioctl,
1519 .splice_read = generic_file_splice_read,
1520 .splice_write = generic_file_splice_write,
1523 int ioctl_by_bdev(struct block_device *bdev, unsigned cmd, unsigned long arg)
1526 mm_segment_t old_fs = get_fs();
1528 res = blkdev_ioctl(bdev, 0, cmd, arg);
1533 EXPORT_SYMBOL(ioctl_by_bdev);
1536 * lookup_bdev - lookup a struct block_device by name
1537 * @pathname: special file representing the block device
1539 * Get a reference to the blockdevice at @pathname in the current
1540 * namespace if possible and return it. Return ERR_PTR(error)
1543 struct block_device *lookup_bdev(const char *pathname)
1545 struct block_device *bdev;
1546 struct inode *inode;
1550 if (!pathname || !*pathname)
1551 return ERR_PTR(-EINVAL);
1553 error = kern_path(pathname, LOOKUP_FOLLOW, &path);
1555 return ERR_PTR(error);
1557 inode = path.dentry->d_inode;
1559 if (!S_ISBLK(inode->i_mode))
1562 if (path.mnt->mnt_flags & MNT_NODEV)
1565 bdev = bd_acquire(inode);
1572 bdev = ERR_PTR(error);
1575 EXPORT_SYMBOL(lookup_bdev);
1578 * open_bdev_exclusive - open a block device by name and set it up for use
1580 * @path: special file representing the block device
1581 * @mode: FMODE_... combination to pass be used
1582 * @holder: owner for exclusion
1584 * Open the blockdevice described by the special file at @path, claim it
1587 struct block_device *open_bdev_exclusive(const char *path, fmode_t mode, void *holder)
1589 struct block_device *bdev;
1592 bdev = lookup_bdev(path);
1596 error = blkdev_get(bdev, mode);
1598 return ERR_PTR(error);
1600 if ((mode & FMODE_WRITE) && bdev_read_only(bdev))
1602 error = bd_claim(bdev, holder);
1609 blkdev_put(bdev, mode);
1610 return ERR_PTR(error);
1613 EXPORT_SYMBOL(open_bdev_exclusive);
1616 * close_bdev_exclusive - close a blockdevice opened by open_bdev_exclusive()
1618 * @bdev: blockdevice to close
1619 * @mode: mode, must match that used to open.
1621 * This is the counterpart to open_bdev_exclusive().
1623 void close_bdev_exclusive(struct block_device *bdev, fmode_t mode)
1626 blkdev_put(bdev, mode);
1629 EXPORT_SYMBOL(close_bdev_exclusive);
1631 int __invalidate_device(struct block_device *bdev)
1633 struct super_block *sb = get_super(bdev);
1638 * no need to lock the super, get_super holds the
1639 * read mutex so the filesystem cannot go away
1640 * under us (->put_super runs with the write lock
1643 shrink_dcache_sb(sb);
1644 res = invalidate_inodes(sb);
1647 invalidate_bdev(bdev);
1650 EXPORT_SYMBOL(__invalidate_device);