block_dev.c 33.0 KB
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/*
 *  linux/fs/block_dev.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *  Copyright (C) 2001  Andrea Arcangeli <andrea@suse.de> SuSE
 */

#include <linux/init.h>
#include <linux/mm.h>
#include <linux/fcntl.h>
#include <linux/slab.h>
#include <linux/kmod.h>
#include <linux/major.h>
#include <linux/smp_lock.h>
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#include <linux/device_cgroup.h>
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#include <linux/highmem.h>
#include <linux/blkdev.h>
#include <linux/module.h>
#include <linux/blkpg.h>
#include <linux/buffer_head.h>
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#include <linux/writeback.h>
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#include <linux/mpage.h>
#include <linux/mount.h>
#include <linux/uio.h>
#include <linux/namei.h>
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#include <linux/log2.h>
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#include <asm/uaccess.h>
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#include "internal.h"
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struct bdev_inode {
	struct block_device bdev;
	struct inode vfs_inode;
};

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static const struct address_space_operations def_blk_aops;

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static inline struct bdev_inode *BDEV_I(struct inode *inode)
{
	return container_of(inode, struct bdev_inode, vfs_inode);
}

inline struct block_device *I_BDEV(struct inode *inode)
{
	return &BDEV_I(inode)->bdev;
}

EXPORT_SYMBOL(I_BDEV);

static sector_t max_block(struct block_device *bdev)
{
	sector_t retval = ~((sector_t)0);
	loff_t sz = i_size_read(bdev->bd_inode);

	if (sz) {
		unsigned int size = block_size(bdev);
		unsigned int sizebits = blksize_bits(size);
		retval = (sz >> sizebits);
	}
	return retval;
}

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/* Kill _all_ buffers and pagecache , dirty or not.. */
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static void kill_bdev(struct block_device *bdev)
{
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	if (bdev->bd_inode->i_mapping->nrpages == 0)
		return;
	invalidate_bh_lrus();
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	truncate_inode_pages(bdev->bd_inode->i_mapping, 0);
}	

int set_blocksize(struct block_device *bdev, int size)
{
	/* Size must be a power of two, and between 512 and PAGE_SIZE */
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	if (size > PAGE_SIZE || size < 512 || !is_power_of_2(size))
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		return -EINVAL;

	/* Size cannot be smaller than the size supported by the device */
	if (size < bdev_hardsect_size(bdev))
		return -EINVAL;

	/* Don't change the size if it is same as current */
	if (bdev->bd_block_size != size) {
		sync_blockdev(bdev);
		bdev->bd_block_size = size;
		bdev->bd_inode->i_blkbits = blksize_bits(size);
		kill_bdev(bdev);
	}
	return 0;
}

EXPORT_SYMBOL(set_blocksize);

int sb_set_blocksize(struct super_block *sb, int size)
{
	if (set_blocksize(sb->s_bdev, size))
		return 0;
	/* If we get here, we know size is power of two
	 * and it's value is between 512 and PAGE_SIZE */
	sb->s_blocksize = size;
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	sb->s_blocksize_bits = blksize_bits(size);
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	return sb->s_blocksize;
}

EXPORT_SYMBOL(sb_set_blocksize);

int sb_min_blocksize(struct super_block *sb, int size)
{
	int minsize = bdev_hardsect_size(sb->s_bdev);
	if (size < minsize)
		size = minsize;
	return sb_set_blocksize(sb, size);
}

EXPORT_SYMBOL(sb_min_blocksize);

static int
blkdev_get_block(struct inode *inode, sector_t iblock,
		struct buffer_head *bh, int create)
{
	if (iblock >= max_block(I_BDEV(inode))) {
		if (create)
			return -EIO;

		/*
		 * for reads, we're just trying to fill a partial page.
		 * return a hole, they will have to call get_block again
		 * before they can fill it, and they will get -EIO at that
		 * time
		 */
		return 0;
	}
	bh->b_bdev = I_BDEV(inode);
	bh->b_blocknr = iblock;
	set_buffer_mapped(bh);
	return 0;
}

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static int
blkdev_get_blocks(struct inode *inode, sector_t iblock,
		struct buffer_head *bh, int create)
{
	sector_t end_block = max_block(I_BDEV(inode));
	unsigned long max_blocks = bh->b_size >> inode->i_blkbits;

	if ((iblock + max_blocks) > end_block) {
		max_blocks = end_block - iblock;
		if ((long)max_blocks <= 0) {
			if (create)
				return -EIO;	/* write fully beyond EOF */
			/*
			 * It is a read which is fully beyond EOF.  We return
			 * a !buffer_mapped buffer
			 */
			max_blocks = 0;
		}
	}

	bh->b_bdev = I_BDEV(inode);
	bh->b_blocknr = iblock;
	bh->b_size = max_blocks << inode->i_blkbits;
	if (max_blocks)
		set_buffer_mapped(bh);
	return 0;
}

static ssize_t
blkdev_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
			loff_t offset, unsigned long nr_segs)
{
	struct file *file = iocb->ki_filp;
	struct inode *inode = file->f_mapping->host;

	return blockdev_direct_IO_no_locking(rw, iocb, inode, I_BDEV(inode),
				iov, offset, nr_segs, blkdev_get_blocks, NULL);
}

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static int blkdev_writepage(struct page *page, struct writeback_control *wbc)
{
	return block_write_full_page(page, blkdev_get_block, wbc);
}

static int blkdev_readpage(struct file * file, struct page * page)
{
	return block_read_full_page(page, blkdev_get_block);
}

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static int blkdev_write_begin(struct file *file, struct address_space *mapping,
			loff_t pos, unsigned len, unsigned flags,
			struct page **pagep, void **fsdata)
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{
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	*pagep = NULL;
	return block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
				blkdev_get_block);
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}

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static int blkdev_write_end(struct file *file, struct address_space *mapping,
			loff_t pos, unsigned len, unsigned copied,
			struct page *page, void *fsdata)
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{
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	int ret;
	ret = block_write_end(file, mapping, pos, len, copied, page, fsdata);

	unlock_page(page);
	page_cache_release(page);

	return ret;
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}

/*
 * private llseek:
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 * for a block special file file->f_path.dentry->d_inode->i_size is zero
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 * so we compute the size by hand (just as in block_read/write above)
 */
static loff_t block_llseek(struct file *file, loff_t offset, int origin)
{
	struct inode *bd_inode = file->f_mapping->host;
	loff_t size;
	loff_t retval;

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	mutex_lock(&bd_inode->i_mutex);
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	size = i_size_read(bd_inode);

	switch (origin) {
		case 2:
			offset += size;
			break;
		case 1:
			offset += file->f_pos;
	}
	retval = -EINVAL;
	if (offset >= 0 && offset <= size) {
		if (offset != file->f_pos) {
			file->f_pos = offset;
		}
		retval = offset;
	}
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	mutex_unlock(&bd_inode->i_mutex);
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	return retval;
}
	
/*
 *	Filp is never NULL; the only case when ->fsync() is called with
 *	NULL first argument is nfsd_sync_dir() and that's not a directory.
 */
 
static int block_fsync(struct file *filp, struct dentry *dentry, int datasync)
{
	return sync_blockdev(I_BDEV(filp->f_mapping->host));
}

/*
 * pseudo-fs
 */

static  __cacheline_aligned_in_smp DEFINE_SPINLOCK(bdev_lock);
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static struct kmem_cache * bdev_cachep __read_mostly;
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static struct inode *bdev_alloc_inode(struct super_block *sb)
{
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	struct bdev_inode *ei = kmem_cache_alloc(bdev_cachep, GFP_KERNEL);
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	if (!ei)
		return NULL;
	return &ei->vfs_inode;
}

static void bdev_destroy_inode(struct inode *inode)
{
	struct bdev_inode *bdi = BDEV_I(inode);

	bdi->bdev.bd_inode_backing_dev_info = NULL;
	kmem_cache_free(bdev_cachep, bdi);
}

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static void init_once(void *foo)
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{
	struct bdev_inode *ei = (struct bdev_inode *) foo;
	struct block_device *bdev = &ei->bdev;

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	memset(bdev, 0, sizeof(*bdev));
	mutex_init(&bdev->bd_mutex);
	sema_init(&bdev->bd_mount_sem, 1);
	INIT_LIST_HEAD(&bdev->bd_inodes);
	INIT_LIST_HEAD(&bdev->bd_list);
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#ifdef CONFIG_SYSFS
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	INIT_LIST_HEAD(&bdev->bd_holder_list);
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#endif
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	inode_init_once(&ei->vfs_inode);
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	/* Initialize mutex for freeze. */
	mutex_init(&bdev->bd_fsfreeze_mutex);
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}

static inline void __bd_forget(struct inode *inode)
{
	list_del_init(&inode->i_devices);
	inode->i_bdev = NULL;
	inode->i_mapping = &inode->i_data;
}

static void bdev_clear_inode(struct inode *inode)
{
	struct block_device *bdev = &BDEV_I(inode)->bdev;
	struct list_head *p;
	spin_lock(&bdev_lock);
	while ( (p = bdev->bd_inodes.next) != &bdev->bd_inodes ) {
		__bd_forget(list_entry(p, struct inode, i_devices));
	}
	list_del_init(&bdev->bd_list);
	spin_unlock(&bdev_lock);
}

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static const struct super_operations bdev_sops = {
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	.statfs = simple_statfs,
	.alloc_inode = bdev_alloc_inode,
	.destroy_inode = bdev_destroy_inode,
	.drop_inode = generic_delete_inode,
	.clear_inode = bdev_clear_inode,
};

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static int bd_get_sb(struct file_system_type *fs_type,
	int flags, const char *dev_name, void *data, struct vfsmount *mnt)
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{
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	return get_sb_pseudo(fs_type, "bdev:", &bdev_sops, 0x62646576, mnt);
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}

static struct file_system_type bd_type = {
	.name		= "bdev",
	.get_sb		= bd_get_sb,
	.kill_sb	= kill_anon_super,
};

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struct super_block *blockdev_superblock __read_mostly;
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void __init bdev_cache_init(void)
{
	int err;
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	struct vfsmount *bd_mnt;

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	bdev_cachep = kmem_cache_create("bdev_cache", sizeof(struct bdev_inode),
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			0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
				SLAB_MEM_SPREAD|SLAB_PANIC),
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			init_once);
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	err = register_filesystem(&bd_type);
	if (err)
		panic("Cannot register bdev pseudo-fs");
	bd_mnt = kern_mount(&bd_type);
	if (IS_ERR(bd_mnt))
		panic("Cannot create bdev pseudo-fs");
	blockdev_superblock = bd_mnt->mnt_sb;	/* For writeback */
}

/*
 * Most likely _very_ bad one - but then it's hardly critical for small
 * /dev and can be fixed when somebody will need really large one.
 * Keep in mind that it will be fed through icache hash function too.
 */
static inline unsigned long hash(dev_t dev)
{
	return MAJOR(dev)+MINOR(dev);
}

static int bdev_test(struct inode *inode, void *data)
{
	return BDEV_I(inode)->bdev.bd_dev == *(dev_t *)data;
}

static int bdev_set(struct inode *inode, void *data)
{
	BDEV_I(inode)->bdev.bd_dev = *(dev_t *)data;
	return 0;
}

static LIST_HEAD(all_bdevs);

struct block_device *bdget(dev_t dev)
{
	struct block_device *bdev;
	struct inode *inode;

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	inode = iget5_locked(blockdev_superblock, hash(dev),
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			bdev_test, bdev_set, &dev);

	if (!inode)
		return NULL;

	bdev = &BDEV_I(inode)->bdev;

	if (inode->i_state & I_NEW) {
		bdev->bd_contains = NULL;
		bdev->bd_inode = inode;
		bdev->bd_block_size = (1 << inode->i_blkbits);
		bdev->bd_part_count = 0;
		bdev->bd_invalidated = 0;
		inode->i_mode = S_IFBLK;
		inode->i_rdev = dev;
		inode->i_bdev = bdev;
		inode->i_data.a_ops = &def_blk_aops;
		mapping_set_gfp_mask(&inode->i_data, GFP_USER);
		inode->i_data.backing_dev_info = &default_backing_dev_info;
		spin_lock(&bdev_lock);
		list_add(&bdev->bd_list, &all_bdevs);
		spin_unlock(&bdev_lock);
		unlock_new_inode(inode);
	}
	return bdev;
}

EXPORT_SYMBOL(bdget);

long nr_blockdev_pages(void)
{
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	struct block_device *bdev;
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	long ret = 0;
	spin_lock(&bdev_lock);
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	list_for_each_entry(bdev, &all_bdevs, bd_list) {
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		ret += bdev->bd_inode->i_mapping->nrpages;
	}
	spin_unlock(&bdev_lock);
	return ret;
}

void bdput(struct block_device *bdev)
{
	iput(bdev->bd_inode);
}

EXPORT_SYMBOL(bdput);
 
static struct block_device *bd_acquire(struct inode *inode)
{
	struct block_device *bdev;
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	spin_lock(&bdev_lock);
	bdev = inode->i_bdev;
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	if (bdev) {
		atomic_inc(&bdev->bd_inode->i_count);
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		spin_unlock(&bdev_lock);
		return bdev;
	}
	spin_unlock(&bdev_lock);
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	bdev = bdget(inode->i_rdev);
	if (bdev) {
		spin_lock(&bdev_lock);
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		if (!inode->i_bdev) {
			/*
			 * We take an additional bd_inode->i_count for inode,
			 * and it's released in clear_inode() of inode.
			 * So, we can access it via ->i_mapping always
			 * without igrab().
			 */
			atomic_inc(&bdev->bd_inode->i_count);
			inode->i_bdev = bdev;
			inode->i_mapping = bdev->bd_inode->i_mapping;
			list_add(&inode->i_devices, &bdev->bd_inodes);
		}
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		spin_unlock(&bdev_lock);
	}
	return bdev;
}

/* Call when you free inode */

void bd_forget(struct inode *inode)
{
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	struct block_device *bdev = NULL;

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	spin_lock(&bdev_lock);
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	if (inode->i_bdev) {
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		if (!sb_is_blkdev_sb(inode->i_sb))
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			bdev = inode->i_bdev;
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		__bd_forget(inode);
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	}
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	spin_unlock(&bdev_lock);
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	if (bdev)
		iput(bdev->bd_inode);
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}

int bd_claim(struct block_device *bdev, void *holder)
{
	int res;
	spin_lock(&bdev_lock);

	/* first decide result */
	if (bdev->bd_holder == holder)
		res = 0;	 /* already a holder */
	else if (bdev->bd_holder != NULL)
		res = -EBUSY; 	 /* held by someone else */
	else if (bdev->bd_contains == bdev)
		res = 0;  	 /* is a whole device which isn't held */

	else if (bdev->bd_contains->bd_holder == bd_claim)
		res = 0; 	 /* is a partition of a device that is being partitioned */
	else if (bdev->bd_contains->bd_holder != NULL)
		res = -EBUSY;	 /* is a partition of a held device */
	else
		res = 0;	 /* is a partition of an un-held device */

	/* now impose change */
	if (res==0) {
		/* note that for a whole device bd_holders
		 * will be incremented twice, and bd_holder will
		 * be set to bd_claim before being set to holder
		 */
		bdev->bd_contains->bd_holders ++;
		bdev->bd_contains->bd_holder = bd_claim;
		bdev->bd_holders++;
		bdev->bd_holder = holder;
	}
	spin_unlock(&bdev_lock);
	return res;
}

EXPORT_SYMBOL(bd_claim);

void bd_release(struct block_device *bdev)
{
	spin_lock(&bdev_lock);
	if (!--bdev->bd_contains->bd_holders)
		bdev->bd_contains->bd_holder = NULL;
	if (!--bdev->bd_holders)
		bdev->bd_holder = NULL;
	spin_unlock(&bdev_lock);
}

EXPORT_SYMBOL(bd_release);

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#ifdef CONFIG_SYSFS
/*
 * Functions for bd_claim_by_kobject / bd_release_from_kobject
 *
 *     If a kobject is passed to bd_claim_by_kobject()
 *     and the kobject has a parent directory,
 *     following symlinks are created:
 *        o from the kobject to the claimed bdev
 *        o from "holders" directory of the bdev to the parent of the kobject
 *     bd_release_from_kobject() removes these symlinks.
 *
 *     Example:
 *        If /dev/dm-0 maps to /dev/sda, kobject corresponding to
 *        /sys/block/dm-0/slaves is passed to bd_claim_by_kobject(), then:
 *           /sys/block/dm-0/slaves/sda --> /sys/block/sda
 *           /sys/block/sda/holders/dm-0 --> /sys/block/dm-0
 */

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static int add_symlink(struct kobject *from, struct kobject *to)
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{
	if (!from || !to)
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		return 0;
	return sysfs_create_link(from, to, kobject_name(to));
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}

static void del_symlink(struct kobject *from, struct kobject *to)
{
	if (!from || !to)
		return;
	sysfs_remove_link(from, kobject_name(to));
}

/*
 * 'struct bd_holder' contains pointers to kobjects symlinked by
 * bd_claim_by_kobject.
 * It's connected to bd_holder_list which is protected by bdev->bd_sem.
 */
struct bd_holder {
	struct list_head list;	/* chain of holders of the bdev */
	int count;		/* references from the holder */
	struct kobject *sdir;	/* holder object, e.g. "/block/dm-0/slaves" */
	struct kobject *hdev;	/* e.g. "/block/dm-0" */
	struct kobject *hdir;	/* e.g. "/block/sda/holders" */
	struct kobject *sdev;	/* e.g. "/block/sda" */
};

/*
 * Get references of related kobjects at once.
 * Returns 1 on success. 0 on failure.
 *
 * Should call bd_holder_release_dirs() after successful use.
 */
static int bd_holder_grab_dirs(struct block_device *bdev,
			struct bd_holder *bo)
{
	if (!bdev || !bo)
		return 0;

	bo->sdir = kobject_get(bo->sdir);
	if (!bo->sdir)
		return 0;

	bo->hdev = kobject_get(bo->sdir->parent);
	if (!bo->hdev)
		goto fail_put_sdir;

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	bo->sdev = kobject_get(&part_to_dev(bdev->bd_part)->kobj);
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	if (!bo->sdev)
		goto fail_put_hdev;

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	bo->hdir = kobject_get(bdev->bd_part->holder_dir);
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	if (!bo->hdir)
		goto fail_put_sdev;

	return 1;

fail_put_sdev:
	kobject_put(bo->sdev);
fail_put_hdev:
	kobject_put(bo->hdev);
fail_put_sdir:
	kobject_put(bo->sdir);

	return 0;
}

/* Put references of related kobjects at once. */
static void bd_holder_release_dirs(struct bd_holder *bo)
{
	kobject_put(bo->hdir);
	kobject_put(bo->sdev);
	kobject_put(bo->hdev);
	kobject_put(bo->sdir);
}

static struct bd_holder *alloc_bd_holder(struct kobject *kobj)
{
	struct bd_holder *bo;

	bo = kzalloc(sizeof(*bo), GFP_KERNEL);
	if (!bo)
		return NULL;

	bo->count = 1;
	bo->sdir = kobj;

	return bo;
}

static void free_bd_holder(struct bd_holder *bo)
{
	kfree(bo);
}

J
Jun'ichi Nomura 已提交
642 643 644 645 646 647 648 649 650 651
/**
 * find_bd_holder - find matching struct bd_holder from the block device
 *
 * @bdev:	struct block device to be searched
 * @bo:		target struct bd_holder
 *
 * Returns matching entry with @bo in @bdev->bd_holder_list.
 * If found, increment the reference count and return the pointer.
 * If not found, returns NULL.
 */
A
Andrew Morton 已提交
652 653
static struct bd_holder *find_bd_holder(struct block_device *bdev,
					struct bd_holder *bo)
J
Jun'ichi Nomura 已提交
654 655 656 657 658 659 660 661 662 663 664 665
{
	struct bd_holder *tmp;

	list_for_each_entry(tmp, &bdev->bd_holder_list, list)
		if (tmp->sdir == bo->sdir) {
			tmp->count++;
			return tmp;
		}

	return NULL;
}

666 667 668 669 670 671
/**
 * add_bd_holder - create sysfs symlinks for bd_claim() relationship
 *
 * @bdev:	block device to be bd_claimed
 * @bo:		preallocated and initialized by alloc_bd_holder()
 *
J
Jun'ichi Nomura 已提交
672
 * Add @bo to @bdev->bd_holder_list, create symlinks.
673
 *
J
Jun'ichi Nomura 已提交
674 675
 * Returns 0 if symlinks are created.
 * Returns -ve if something fails.
676 677 678
 */
static int add_bd_holder(struct block_device *bdev, struct bd_holder *bo)
{
679
	int err;
680 681

	if (!bo)
682
		return -EINVAL;
683 684

	if (!bd_holder_grab_dirs(bdev, bo))
685
		return -EBUSY;
686

687 688 689 690 691 692 693 694
	err = add_symlink(bo->sdir, bo->sdev);
	if (err)
		return err;

	err = add_symlink(bo->hdir, bo->hdev);
	if (err) {
		del_symlink(bo->sdir, bo->sdev);
		return err;
695
	}
696 697 698

	list_add_tail(&bo->list, &bdev->bd_holder_list);
	return 0;
699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755
}

/**
 * del_bd_holder - delete sysfs symlinks for bd_claim() relationship
 *
 * @bdev:	block device to be bd_claimed
 * @kobj:	holder's kobject
 *
 * If there is matching entry with @kobj in @bdev->bd_holder_list
 * and no other bd_claim() from the same kobject,
 * remove the struct bd_holder from the list, delete symlinks for it.
 *
 * Returns a pointer to the struct bd_holder when it's removed from the list
 * and ready to be freed.
 * Returns NULL if matching claim isn't found or there is other bd_claim()
 * by the same kobject.
 */
static struct bd_holder *del_bd_holder(struct block_device *bdev,
					struct kobject *kobj)
{
	struct bd_holder *bo;

	list_for_each_entry(bo, &bdev->bd_holder_list, list) {
		if (bo->sdir == kobj) {
			bo->count--;
			BUG_ON(bo->count < 0);
			if (!bo->count) {
				list_del(&bo->list);
				del_symlink(bo->sdir, bo->sdev);
				del_symlink(bo->hdir, bo->hdev);
				bd_holder_release_dirs(bo);
				return bo;
			}
			break;
		}
	}

	return NULL;
}

/**
 * bd_claim_by_kobject - bd_claim() with additional kobject signature
 *
 * @bdev:	block device to be claimed
 * @holder:	holder's signature
 * @kobj:	holder's kobject
 *
 * Do bd_claim() and if it succeeds, create sysfs symlinks between
 * the bdev and the holder's kobject.
 * Use bd_release_from_kobject() when relesing the claimed bdev.
 *
 * Returns 0 on success. (same as bd_claim())
 * Returns errno on failure.
 */
static int bd_claim_by_kobject(struct block_device *bdev, void *holder,
				struct kobject *kobj)
{
756
	int err;
J
Jun'ichi Nomura 已提交
757
	struct bd_holder *bo, *found;
758 759 760 761 762 763 764 765

	if (!kobj)
		return -EINVAL;

	bo = alloc_bd_holder(kobj);
	if (!bo)
		return -ENOMEM;

766
	mutex_lock(&bdev->bd_mutex);
J
Jun'ichi Nomura 已提交
767

768 769
	err = bd_claim(bdev, holder);
	if (err)
A
Andrew Morton 已提交
770
		goto fail;
771 772 773

	found = find_bd_holder(bdev, bo);
	if (found)
A
Andrew Morton 已提交
774
		goto fail;
775 776 777 778

	err = add_bd_holder(bdev, bo);
	if (err)
		bd_release(bdev);
A
Andrew Morton 已提交
779 780 781
	else
		bo = NULL;
fail:
782
	mutex_unlock(&bdev->bd_mutex);
A
Andrew Morton 已提交
783
	free_bd_holder(bo);
784
	return err;
785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800
}

/**
 * bd_release_from_kobject - bd_release() with additional kobject signature
 *
 * @bdev:	block device to be released
 * @kobj:	holder's kobject
 *
 * Do bd_release() and remove sysfs symlinks created by bd_claim_by_kobject().
 */
static void bd_release_from_kobject(struct block_device *bdev,
					struct kobject *kobj)
{
	if (!kobj)
		return;

801
	mutex_lock(&bdev->bd_mutex);
802
	bd_release(bdev);
A
Andrew Morton 已提交
803
	free_bd_holder(del_bd_holder(bdev, kobj));
804
	mutex_unlock(&bdev->bd_mutex);
805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838
}

/**
 * bd_claim_by_disk - wrapper function for bd_claim_by_kobject()
 *
 * @bdev:	block device to be claimed
 * @holder:	holder's signature
 * @disk:	holder's gendisk
 *
 * Call bd_claim_by_kobject() with getting @disk->slave_dir.
 */
int bd_claim_by_disk(struct block_device *bdev, void *holder,
			struct gendisk *disk)
{
	return bd_claim_by_kobject(bdev, holder, kobject_get(disk->slave_dir));
}
EXPORT_SYMBOL_GPL(bd_claim_by_disk);

/**
 * bd_release_from_disk - wrapper function for bd_release_from_kobject()
 *
 * @bdev:	block device to be claimed
 * @disk:	holder's gendisk
 *
 * Call bd_release_from_kobject() and put @disk->slave_dir.
 */
void bd_release_from_disk(struct block_device *bdev, struct gendisk *disk)
{
	bd_release_from_kobject(bdev, disk->slave_dir);
	kobject_put(disk->slave_dir);
}
EXPORT_SYMBOL_GPL(bd_release_from_disk);
#endif

L
Linus Torvalds 已提交
839 840 841 842 843 844 845
/*
 * Tries to open block device by device number.  Use it ONLY if you
 * really do not have anything better - i.e. when you are behind a
 * truly sucky interface and all you are given is a device number.  _Never_
 * to be used for internal purposes.  If you ever need it - reconsider
 * your API.
 */
846
struct block_device *open_by_devnum(dev_t dev, fmode_t mode)
L
Linus Torvalds 已提交
847 848 849 850
{
	struct block_device *bdev = bdget(dev);
	int err = -ENOMEM;
	if (bdev)
851
		err = blkdev_get(bdev, mode);
L
Linus Torvalds 已提交
852 853 854 855 856
	return err ? ERR_PTR(err) : bdev;
}

EXPORT_SYMBOL(open_by_devnum);

857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882
/**
 * flush_disk - invalidates all buffer-cache entries on a disk
 *
 * @bdev:      struct block device to be flushed
 *
 * Invalidates all buffer-cache entries on a disk. It should be called
 * when a disk has been changed -- either by a media change or online
 * resize.
 */
static void flush_disk(struct block_device *bdev)
{
	if (__invalidate_device(bdev)) {
		char name[BDEVNAME_SIZE] = "";

		if (bdev->bd_disk)
			disk_name(bdev->bd_disk, 0, name);
		printk(KERN_WARNING "VFS: busy inodes on changed media or "
		       "resized disk %s\n", name);
	}

	if (!bdev->bd_disk)
		return;
	if (disk_partitionable(bdev->bd_disk))
		bdev->bd_invalidated = 1;
}

883
/**
884
 * check_disk_size_change - checks for disk size change and adjusts bdev size.
885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904
 * @disk: struct gendisk to check
 * @bdev: struct bdev to adjust.
 *
 * This routine checks to see if the bdev size does not match the disk size
 * and adjusts it if it differs.
 */
void check_disk_size_change(struct gendisk *disk, struct block_device *bdev)
{
	loff_t disk_size, bdev_size;

	disk_size = (loff_t)get_capacity(disk) << 9;
	bdev_size = i_size_read(bdev->bd_inode);
	if (disk_size != bdev_size) {
		char name[BDEVNAME_SIZE];

		disk_name(disk, 0, name);
		printk(KERN_INFO
		       "%s: detected capacity change from %lld to %lld\n",
		       name, bdev_size, disk_size);
		i_size_write(bdev->bd_inode, disk_size);
905
		flush_disk(bdev);
906 907 908 909
	}
}
EXPORT_SYMBOL(check_disk_size_change);

910
/**
911
 * revalidate_disk - wrapper for lower-level driver's revalidate_disk call-back
912 913 914 915 916 917 918 919
 * @disk: struct gendisk to be revalidated
 *
 * This routine is a wrapper for lower-level driver's revalidate_disk
 * call-backs.  It is used to do common pre and post operations needed
 * for all revalidate_disk operations.
 */
int revalidate_disk(struct gendisk *disk)
{
920
	struct block_device *bdev;
921 922 923 924 925
	int ret = 0;

	if (disk->fops->revalidate_disk)
		ret = disk->fops->revalidate_disk(disk);

926 927 928 929 930 931 932 933
	bdev = bdget_disk(disk, 0);
	if (!bdev)
		return ret;

	mutex_lock(&bdev->bd_mutex);
	check_disk_size_change(disk, bdev);
	mutex_unlock(&bdev->bd_mutex);
	bdput(bdev);
934 935 936 937
	return ret;
}
EXPORT_SYMBOL(revalidate_disk);

L
Linus Torvalds 已提交
938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956
/*
 * This routine checks whether a removable media has been changed,
 * and invalidates all buffer-cache-entries in that case. This
 * is a relatively slow routine, so we have to try to minimize using
 * it. Thus it is called only upon a 'mount' or 'open'. This
 * is the best way of combining speed and utility, I think.
 * People changing diskettes in the middle of an operation deserve
 * to lose :-)
 */
int check_disk_change(struct block_device *bdev)
{
	struct gendisk *disk = bdev->bd_disk;
	struct block_device_operations * bdops = disk->fops;

	if (!bdops->media_changed)
		return 0;
	if (!bdops->media_changed(bdev->bd_disk))
		return 0;

957
	flush_disk(bdev);
L
Linus Torvalds 已提交
958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979
	if (bdops->revalidate_disk)
		bdops->revalidate_disk(bdev->bd_disk);
	return 1;
}

EXPORT_SYMBOL(check_disk_change);

void bd_set_size(struct block_device *bdev, loff_t size)
{
	unsigned bsize = bdev_hardsect_size(bdev);

	bdev->bd_inode->i_size = size;
	while (bsize < PAGE_CACHE_SIZE) {
		if (size & bsize)
			break;
		bsize <<= 1;
	}
	bdev->bd_block_size = bsize;
	bdev->bd_inode->i_blkbits = blksize_bits(bsize);
}
EXPORT_SYMBOL(bd_set_size);

A
Al Viro 已提交
980
static int __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part);
981

982 983 984 985 986 987 988
/*
 * bd_mutex locking:
 *
 *  mutex_lock(part->bd_mutex)
 *    mutex_lock_nested(whole->bd_mutex, 1)
 */

989
static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
L
Linus Torvalds 已提交
990 991
{
	struct gendisk *disk;
992
	int ret;
993
	int partno;
994 995
	int perm = 0;

996
	if (mode & FMODE_READ)
997
		perm |= MAY_READ;
998
	if (mode & FMODE_WRITE)
999 1000 1001 1002 1003
		perm |= MAY_WRITE;
	/*
	 * hooks: /n/, see "layering violations".
	 */
	ret = devcgroup_inode_permission(bdev->bd_inode, perm);
1004 1005
	if (ret != 0) {
		bdput(bdev);
1006
		return ret;
1007
	}
1008

L
Linus Torvalds 已提交
1009
	lock_kernel();
1010
 restart:
T
Tejun Heo 已提交
1011

1012
	ret = -ENXIO;
1013
	disk = get_gendisk(bdev->bd_dev, &partno);
T
Tejun Heo 已提交
1014 1015
	if (!disk)
		goto out_unlock_kernel;
L
Linus Torvalds 已提交
1016

1017
	mutex_lock_nested(&bdev->bd_mutex, for_part);
L
Linus Torvalds 已提交
1018 1019 1020
	if (!bdev->bd_openers) {
		bdev->bd_disk = disk;
		bdev->bd_contains = bdev;
1021
		if (!partno) {
L
Linus Torvalds 已提交
1022
			struct backing_dev_info *bdi;
1023 1024 1025 1026 1027 1028

			ret = -ENXIO;
			bdev->bd_part = disk_get_part(disk, partno);
			if (!bdev->bd_part)
				goto out_clear;

L
Linus Torvalds 已提交
1029
			if (disk->fops->open) {
1030
				ret = disk->fops->open(bdev, mode);
1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043
				if (ret == -ERESTARTSYS) {
					/* Lost a race with 'disk' being
					 * deleted, try again.
					 * See md.c
					 */
					disk_put_part(bdev->bd_part);
					bdev->bd_part = NULL;
					module_put(disk->fops->owner);
					put_disk(disk);
					bdev->bd_disk = NULL;
					mutex_unlock(&bdev->bd_mutex);
					goto restart;
				}
L
Linus Torvalds 已提交
1044
				if (ret)
T
Tejun Heo 已提交
1045
					goto out_clear;
L
Linus Torvalds 已提交
1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060
			}
			if (!bdev->bd_openers) {
				bd_set_size(bdev,(loff_t)get_capacity(disk)<<9);
				bdi = blk_get_backing_dev_info(bdev);
				if (bdi == NULL)
					bdi = &default_backing_dev_info;
				bdev->bd_inode->i_data.backing_dev_info = bdi;
			}
			if (bdev->bd_invalidated)
				rescan_partitions(disk, bdev);
		} else {
			struct block_device *whole;
			whole = bdget_disk(disk, 0);
			ret = -ENOMEM;
			if (!whole)
T
Tejun Heo 已提交
1061
				goto out_clear;
1062
			BUG_ON(for_part);
1063
			ret = __blkdev_get(whole, mode, 1);
L
Linus Torvalds 已提交
1064
			if (ret)
T
Tejun Heo 已提交
1065
				goto out_clear;
L
Linus Torvalds 已提交
1066 1067 1068
			bdev->bd_contains = whole;
			bdev->bd_inode->i_data.backing_dev_info =
			   whole->bd_inode->i_data.backing_dev_info;
1069
			bdev->bd_part = disk_get_part(disk, partno);
1070
			if (!(disk->flags & GENHD_FL_UP) ||
1071
			    !bdev->bd_part || !bdev->bd_part->nr_sects) {
L
Linus Torvalds 已提交
1072
				ret = -ENXIO;
T
Tejun Heo 已提交
1073
				goto out_clear;
L
Linus Torvalds 已提交
1074
			}
1075
			bd_set_size(bdev, (loff_t)bdev->bd_part->nr_sects << 9);
L
Linus Torvalds 已提交
1076 1077 1078
		}
	} else {
		put_disk(disk);
T
Tejun Heo 已提交
1079 1080
		module_put(disk->fops->owner);
		disk = NULL;
L
Linus Torvalds 已提交
1081 1082
		if (bdev->bd_contains == bdev) {
			if (bdev->bd_disk->fops->open) {
1083
				ret = bdev->bd_disk->fops->open(bdev, mode);
L
Linus Torvalds 已提交
1084
				if (ret)
T
Tejun Heo 已提交
1085
					goto out_unlock_bdev;
L
Linus Torvalds 已提交
1086 1087 1088 1089 1090 1091
			}
			if (bdev->bd_invalidated)
				rescan_partitions(bdev->bd_disk, bdev);
		}
	}
	bdev->bd_openers++;
1092 1093
	if (for_part)
		bdev->bd_part_count++;
1094
	mutex_unlock(&bdev->bd_mutex);
L
Linus Torvalds 已提交
1095 1096 1097
	unlock_kernel();
	return 0;

T
Tejun Heo 已提交
1098
 out_clear:
1099
	disk_put_part(bdev->bd_part);
L
Linus Torvalds 已提交
1100
	bdev->bd_disk = NULL;
T
Tejun Heo 已提交
1101
	bdev->bd_part = NULL;
L
Linus Torvalds 已提交
1102 1103
	bdev->bd_inode->i_data.backing_dev_info = &default_backing_dev_info;
	if (bdev != bdev->bd_contains)
1104
		__blkdev_put(bdev->bd_contains, mode, 1);
L
Linus Torvalds 已提交
1105
	bdev->bd_contains = NULL;
T
Tejun Heo 已提交
1106
 out_unlock_bdev:
1107
	mutex_unlock(&bdev->bd_mutex);
T
Tejun Heo 已提交
1108
 out_unlock_kernel:
L
Linus Torvalds 已提交
1109
	unlock_kernel();
T
Tejun Heo 已提交
1110 1111 1112 1113 1114 1115

	if (disk)
		module_put(disk->fops->owner);
	put_disk(disk);
	bdput(bdev);

L
Linus Torvalds 已提交
1116 1117 1118
	return ret;
}

1119
int blkdev_get(struct block_device *bdev, fmode_t mode)
L
Linus Torvalds 已提交
1120
{
1121
	return __blkdev_get(bdev, mode, 0);
1122
}
L
Linus Torvalds 已提交
1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137
EXPORT_SYMBOL(blkdev_get);

static int blkdev_open(struct inode * inode, struct file * filp)
{
	struct block_device *bdev;
	int res;

	/*
	 * Preserve backwards compatibility and allow large file access
	 * even if userspace doesn't ask for it explicitly. Some mkfs
	 * binary needs it. We might want to drop this workaround
	 * during an unstable branch.
	 */
	filp->f_flags |= O_LARGEFILE;

1138 1139 1140 1141 1142 1143 1144
	if (filp->f_flags & O_NDELAY)
		filp->f_mode |= FMODE_NDELAY;
	if (filp->f_flags & O_EXCL)
		filp->f_mode |= FMODE_EXCL;
	if ((filp->f_flags & O_ACCMODE) == 3)
		filp->f_mode |= FMODE_WRITE_IOCTL;

L
Linus Torvalds 已提交
1145
	bdev = bd_acquire(inode);
1146 1147
	if (bdev == NULL)
		return -ENOMEM;
L
Linus Torvalds 已提交
1148

1149 1150 1151
	filp->f_mapping = bdev->bd_inode->i_mapping;

	res = blkdev_get(bdev, filp->f_mode);
L
Linus Torvalds 已提交
1152 1153 1154
	if (res)
		return res;

1155 1156 1157 1158 1159
	if (filp->f_mode & FMODE_EXCL) {
		res = bd_claim(bdev, filp);
		if (res)
			goto out_blkdev_put;
	}
L
Linus Torvalds 已提交
1160

1161
	return 0;
L
Linus Torvalds 已提交
1162

1163
 out_blkdev_put:
A
Al Viro 已提交
1164
	blkdev_put(bdev, filp->f_mode);
L
Linus Torvalds 已提交
1165 1166 1167
	return res;
}

A
Al Viro 已提交
1168
static int __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part)
1169 1170 1171
{
	int ret = 0;
	struct gendisk *disk = bdev->bd_disk;
1172
	struct block_device *victim = NULL;
1173

1174
	mutex_lock_nested(&bdev->bd_mutex, for_part);
1175
	lock_kernel();
1176 1177 1178
	if (for_part)
		bdev->bd_part_count--;

1179 1180 1181 1182 1183 1184
	if (!--bdev->bd_openers) {
		sync_blockdev(bdev);
		kill_bdev(bdev);
	}
	if (bdev->bd_contains == bdev) {
		if (disk->fops->release)
A
Al Viro 已提交
1185
			ret = disk->fops->release(disk, mode);
1186 1187 1188 1189 1190 1191
	}
	if (!bdev->bd_openers) {
		struct module *owner = disk->fops->owner;

		put_disk(disk);
		module_put(owner);
T
Tejun Heo 已提交
1192 1193
		disk_put_part(bdev->bd_part);
		bdev->bd_part = NULL;
1194 1195
		bdev->bd_disk = NULL;
		bdev->bd_inode->i_data.backing_dev_info = &default_backing_dev_info;
1196 1197
		if (bdev != bdev->bd_contains)
			victim = bdev->bd_contains;
1198 1199 1200 1201 1202
		bdev->bd_contains = NULL;
	}
	unlock_kernel();
	mutex_unlock(&bdev->bd_mutex);
	bdput(bdev);
1203
	if (victim)
A
Al Viro 已提交
1204
		__blkdev_put(victim, mode, 1);
1205 1206 1207
	return ret;
}

A
Al Viro 已提交
1208
int blkdev_put(struct block_device *bdev, fmode_t mode)
1209
{
A
Al Viro 已提交
1210
	return __blkdev_put(bdev, mode, 0);
1211
}
1212 1213
EXPORT_SYMBOL(blkdev_put);

L
Linus Torvalds 已提交
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static int blkdev_close(struct inode * inode, struct file * filp)
{
	struct block_device *bdev = I_BDEV(filp->f_mapping->host);
	if (bdev->bd_holder == filp)
		bd_release(bdev);
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Al Viro 已提交
1219
	return blkdev_put(bdev, filp->f_mode);
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}

1222
static long block_ioctl(struct file *file, unsigned cmd, unsigned long arg)
L
Linus Torvalds 已提交
1223
{
1224 1225
	struct block_device *bdev = I_BDEV(file->f_mapping->host);
	fmode_t mode = file->f_mode;
1226 1227 1228 1229 1230

	/*
	 * O_NDELAY can be altered using fcntl(.., F_SETFL, ..), so we have
	 * to updated it before every ioctl.
	 */
1231
	if (file->f_flags & O_NDELAY)
1232 1233 1234 1235
		mode |= FMODE_NDELAY;
	else
		mode &= ~FMODE_NDELAY;

1236
	return blkdev_ioctl(bdev, mode, cmd, arg);
L
Linus Torvalds 已提交
1237 1238
}

1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252
/*
 * Try to release a page associated with block device when the system
 * is under memory pressure.
 */
static int blkdev_releasepage(struct page *page, gfp_t wait)
{
	struct super_block *super = BDEV_I(page->mapping->host)->bdev.bd_super;

	if (super && super->s_op->bdev_try_to_free_page)
		return super->s_op->bdev_try_to_free_page(super, page, wait);

	return try_to_free_buffers(page);
}

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Adrian Bunk 已提交
1253
static const struct address_space_operations def_blk_aops = {
L
Linus Torvalds 已提交
1254 1255 1256
	.readpage	= blkdev_readpage,
	.writepage	= blkdev_writepage,
	.sync_page	= block_sync_page,
N
Nick Piggin 已提交
1257 1258
	.write_begin	= blkdev_write_begin,
	.write_end	= blkdev_write_end,
L
Linus Torvalds 已提交
1259
	.writepages	= generic_writepages,
1260
	.releasepage	= blkdev_releasepage,
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	.direct_IO	= blkdev_direct_IO,
};

1264
const struct file_operations def_blk_fops = {
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Linus Torvalds 已提交
1265 1266 1267
	.open		= blkdev_open,
	.release	= blkdev_close,
	.llseek		= block_llseek,
1268 1269
	.read		= do_sync_read,
	.write		= do_sync_write,
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Linus Torvalds 已提交
1270
  	.aio_read	= generic_file_aio_read,
1271
  	.aio_write	= generic_file_aio_write_nolock,
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	.mmap		= generic_file_mmap,
	.fsync		= block_fsync,
1274
	.unlocked_ioctl	= block_ioctl,
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1275 1276 1277
#ifdef CONFIG_COMPAT
	.compat_ioctl	= compat_blkdev_ioctl,
#endif
1278 1279
	.splice_read	= generic_file_splice_read,
	.splice_write	= generic_file_splice_write,
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};

int ioctl_by_bdev(struct block_device *bdev, unsigned cmd, unsigned long arg)
{
	int res;
	mm_segment_t old_fs = get_fs();
	set_fs(KERNEL_DS);
1287
	res = blkdev_ioctl(bdev, 0, cmd, arg);
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	set_fs(old_fs);
	return res;
}

EXPORT_SYMBOL(ioctl_by_bdev);

/**
 * lookup_bdev  - lookup a struct block_device by name
1296
 * @pathname:	special file representing the block device
L
Linus Torvalds 已提交
1297
 *
1298
 * Get a reference to the blockdevice at @pathname in the current
L
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1299 1300 1301
 * namespace if possible and return it.  Return ERR_PTR(error)
 * otherwise.
 */
1302
struct block_device *lookup_bdev(const char *pathname)
L
Linus Torvalds 已提交
1303 1304 1305
{
	struct block_device *bdev;
	struct inode *inode;
1306
	struct path path;
L
Linus Torvalds 已提交
1307 1308
	int error;

1309
	if (!pathname || !*pathname)
L
Linus Torvalds 已提交
1310 1311
		return ERR_PTR(-EINVAL);

1312
	error = kern_path(pathname, LOOKUP_FOLLOW, &path);
L
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1313 1314 1315
	if (error)
		return ERR_PTR(error);

1316
	inode = path.dentry->d_inode;
L
Linus Torvalds 已提交
1317 1318 1319 1320
	error = -ENOTBLK;
	if (!S_ISBLK(inode->i_mode))
		goto fail;
	error = -EACCES;
1321
	if (path.mnt->mnt_flags & MNT_NODEV)
L
Linus Torvalds 已提交
1322 1323 1324 1325 1326 1327
		goto fail;
	error = -ENOMEM;
	bdev = bd_acquire(inode);
	if (!bdev)
		goto fail;
out:
1328
	path_put(&path);
L
Linus Torvalds 已提交
1329 1330 1331 1332 1333
	return bdev;
fail:
	bdev = ERR_PTR(error);
	goto out;
}
1334
EXPORT_SYMBOL(lookup_bdev);
L
Linus Torvalds 已提交
1335 1336

/**
1337
 * open_bdev_exclusive  -  open a block device by name and set it up for use
L
Linus Torvalds 已提交
1338 1339
 *
 * @path:	special file representing the block device
1340
 * @mode:	FMODE_... combination to pass be used
L
Linus Torvalds 已提交
1341 1342 1343 1344 1345
 * @holder:	owner for exclusion
 *
 * Open the blockdevice described by the special file at @path, claim it
 * for the @holder.
 */
1346
struct block_device *open_bdev_exclusive(const char *path, fmode_t mode, void *holder)
L
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1347 1348 1349 1350 1351 1352 1353 1354
{
	struct block_device *bdev;
	int error = 0;

	bdev = lookup_bdev(path);
	if (IS_ERR(bdev))
		return bdev;

1355
	error = blkdev_get(bdev, mode);
L
Linus Torvalds 已提交
1356 1357 1358
	if (error)
		return ERR_PTR(error);
	error = -EACCES;
1359
	if ((mode & FMODE_WRITE) && bdev_read_only(bdev))
L
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1360 1361 1362 1363 1364 1365 1366 1367
		goto blkdev_put;
	error = bd_claim(bdev, holder);
	if (error)
		goto blkdev_put;

	return bdev;
	
blkdev_put:
A
Al Viro 已提交
1368
	blkdev_put(bdev, mode);
L
Linus Torvalds 已提交
1369 1370 1371
	return ERR_PTR(error);
}

1372
EXPORT_SYMBOL(open_bdev_exclusive);
L
Linus Torvalds 已提交
1373 1374

/**
1375
 * close_bdev_exclusive  -  close a blockdevice opened by open_bdev_exclusive()
L
Linus Torvalds 已提交
1376 1377
 *
 * @bdev:	blockdevice to close
1378
 * @mode:	mode, must match that used to open.
L
Linus Torvalds 已提交
1379
 *
1380
 * This is the counterpart to open_bdev_exclusive().
L
Linus Torvalds 已提交
1381
 */
1382
void close_bdev_exclusive(struct block_device *bdev, fmode_t mode)
L
Linus Torvalds 已提交
1383 1384
{
	bd_release(bdev);
1385
	blkdev_put(bdev, mode);
L
Linus Torvalds 已提交
1386 1387
}

1388
EXPORT_SYMBOL(close_bdev_exclusive);
1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405

int __invalidate_device(struct block_device *bdev)
{
	struct super_block *sb = get_super(bdev);
	int res = 0;

	if (sb) {
		/*
		 * no need to lock the super, get_super holds the
		 * read mutex so the filesystem cannot go away
		 * under us (->put_super runs with the write lock
		 * hold).
		 */
		shrink_dcache_sb(sb);
		res = invalidate_inodes(sb);
		drop_super(sb);
	}
1406
	invalidate_bdev(bdev);
1407 1408 1409
	return res;
}
EXPORT_SYMBOL(__invalidate_device);