linux_dsm_epyc7002/fs/block_dev.c
Tejun Heo e75aa85892 block_dev: always serialize exclusive open attempts
bd_prepare_to_claim() incorrectly allowed multiple attempts for
exclusive open to progress in parallel if the attempting holders are
identical.  This triggered BUG_ON() as reported in the following bug.

  https://bugzilla.kernel.org/show_bug.cgi?id=16393

__bd_abort_claiming() is used to finish claiming blocks and doesn't
work if multiple openers are inside a claiming block.  Allowing
multiple parallel open attempts to continue doesn't gain anything as
those are serialized down in the call chain anyway.  Fix it by always
allowing only single open attempt in a claiming block.

This problem can easily be reproduced by adding a delay after
bd_prepare_to_claim() and attempting to mount two partitions of a
disk.

stable: only applicable to v2.6.35

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-04 11:17:10 -07:00

1787 lines
43 KiB
C

/*
* 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>
#include <linux/device_cgroup.h>
#include <linux/highmem.h>
#include <linux/blkdev.h>
#include <linux/module.h>
#include <linux/blkpg.h>
#include <linux/buffer_head.h>
#include <linux/pagevec.h>
#include <linux/writeback.h>
#include <linux/mpage.h>
#include <linux/mount.h>
#include <linux/uio.h>
#include <linux/namei.h>
#include <linux/log2.h>
#include <linux/kmemleak.h>
#include <asm/uaccess.h>
#include "internal.h"
struct bdev_inode {
struct block_device bdev;
struct inode vfs_inode;
};
static const struct address_space_operations def_blk_aops;
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;
}
/* Kill _all_ buffers and pagecache , dirty or not.. */
static void kill_bdev(struct block_device *bdev)
{
if (bdev->bd_inode->i_mapping->nrpages == 0)
return;
invalidate_bh_lrus();
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 */
if (size > PAGE_SIZE || size < 512 || !is_power_of_2(size))
return -EINVAL;
/* Size cannot be smaller than the size supported by the device */
if (size < bdev_logical_block_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;
sb->s_blocksize_bits = blksize_bits(size);
return sb->s_blocksize;
}
EXPORT_SYMBOL(sb_set_blocksize);
int sb_min_blocksize(struct super_block *sb, int size)
{
int minsize = bdev_logical_block_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;
}
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_newtrunc(rw, iocb, inode,
I_BDEV(inode), iov, offset, nr_segs,
blkdev_get_blocks, NULL);
}
int __sync_blockdev(struct block_device *bdev, int wait)
{
if (!bdev)
return 0;
if (!wait)
return filemap_flush(bdev->bd_inode->i_mapping);
return filemap_write_and_wait(bdev->bd_inode->i_mapping);
}
/*
* Write out and wait upon all the dirty data associated with a block
* device via its mapping. Does not take the superblock lock.
*/
int sync_blockdev(struct block_device *bdev)
{
return __sync_blockdev(bdev, 1);
}
EXPORT_SYMBOL(sync_blockdev);
/*
* Write out and wait upon all dirty data associated with this
* device. Filesystem data as well as the underlying block
* device. Takes the superblock lock.
*/
int fsync_bdev(struct block_device *bdev)
{
struct super_block *sb = get_super(bdev);
if (sb) {
int res = sync_filesystem(sb);
drop_super(sb);
return res;
}
return sync_blockdev(bdev);
}
EXPORT_SYMBOL(fsync_bdev);
/**
* freeze_bdev -- lock a filesystem and force it into a consistent state
* @bdev: blockdevice to lock
*
* If a superblock is found on this device, we take the s_umount semaphore
* on it to make sure nobody unmounts until the snapshot creation is done.
* The reference counter (bd_fsfreeze_count) guarantees that only the last
* unfreeze process can unfreeze the frozen filesystem actually when multiple
* freeze requests arrive simultaneously. It counts up in freeze_bdev() and
* count down in thaw_bdev(). When it becomes 0, thaw_bdev() will unfreeze
* actually.
*/
struct super_block *freeze_bdev(struct block_device *bdev)
{
struct super_block *sb;
int error = 0;
mutex_lock(&bdev->bd_fsfreeze_mutex);
if (++bdev->bd_fsfreeze_count > 1) {
/*
* We don't even need to grab a reference - the first call
* to freeze_bdev grab an active reference and only the last
* thaw_bdev drops it.
*/
sb = get_super(bdev);
drop_super(sb);
mutex_unlock(&bdev->bd_fsfreeze_mutex);
return sb;
}
sb = get_active_super(bdev);
if (!sb)
goto out;
error = freeze_super(sb);
if (error) {
deactivate_super(sb);
bdev->bd_fsfreeze_count--;
mutex_unlock(&bdev->bd_fsfreeze_mutex);
return ERR_PTR(error);
}
deactivate_super(sb);
out:
sync_blockdev(bdev);
mutex_unlock(&bdev->bd_fsfreeze_mutex);
return sb; /* thaw_bdev releases s->s_umount */
}
EXPORT_SYMBOL(freeze_bdev);
/**
* thaw_bdev -- unlock filesystem
* @bdev: blockdevice to unlock
* @sb: associated superblock
*
* Unlocks the filesystem and marks it writeable again after freeze_bdev().
*/
int thaw_bdev(struct block_device *bdev, struct super_block *sb)
{
int error = -EINVAL;
mutex_lock(&bdev->bd_fsfreeze_mutex);
if (!bdev->bd_fsfreeze_count)
goto out;
error = 0;
if (--bdev->bd_fsfreeze_count > 0)
goto out;
if (!sb)
goto out;
error = thaw_super(sb);
if (error) {
bdev->bd_fsfreeze_count++;
mutex_unlock(&bdev->bd_fsfreeze_mutex);
return error;
}
out:
mutex_unlock(&bdev->bd_fsfreeze_mutex);
return 0;
}
EXPORT_SYMBOL(thaw_bdev);
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);
}
static int blkdev_write_begin(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned flags,
struct page **pagep, void **fsdata)
{
*pagep = NULL;
return block_write_begin_newtrunc(file, mapping, pos, len, flags,
pagep, fsdata, blkdev_get_block);
}
static int blkdev_write_end(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned copied,
struct page *page, void *fsdata)
{
int ret;
ret = block_write_end(file, mapping, pos, len, copied, page, fsdata);
unlock_page(page);
page_cache_release(page);
return ret;
}
/*
* private llseek:
* for a block special file file->f_path.dentry->d_inode->i_size is zero
* 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;
mutex_lock(&bd_inode->i_mutex);
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;
}
mutex_unlock(&bd_inode->i_mutex);
return retval;
}
int blkdev_fsync(struct file *filp, int datasync)
{
struct inode *bd_inode = filp->f_mapping->host;
struct block_device *bdev = I_BDEV(bd_inode);
int error;
/*
* There is no need to serialise calls to blkdev_issue_flush with
* i_mutex and doing so causes performance issues with concurrent
* O_SYNC writers to a block device.
*/
mutex_unlock(&bd_inode->i_mutex);
error = blkdev_issue_flush(bdev, GFP_KERNEL, NULL, BLKDEV_IFL_WAIT);
if (error == -EOPNOTSUPP)
error = 0;
mutex_lock(&bd_inode->i_mutex);
return error;
}
EXPORT_SYMBOL(blkdev_fsync);
/*
* pseudo-fs
*/
static __cacheline_aligned_in_smp DEFINE_SPINLOCK(bdev_lock);
static struct kmem_cache * bdev_cachep __read_mostly;
static struct inode *bdev_alloc_inode(struct super_block *sb)
{
struct bdev_inode *ei = kmem_cache_alloc(bdev_cachep, GFP_KERNEL);
if (!ei)
return NULL;
return &ei->vfs_inode;
}
static void bdev_destroy_inode(struct inode *inode)
{
struct bdev_inode *bdi = BDEV_I(inode);
kmem_cache_free(bdev_cachep, bdi);
}
static void init_once(void *foo)
{
struct bdev_inode *ei = (struct bdev_inode *) foo;
struct block_device *bdev = &ei->bdev;
memset(bdev, 0, sizeof(*bdev));
mutex_init(&bdev->bd_mutex);
INIT_LIST_HEAD(&bdev->bd_inodes);
INIT_LIST_HEAD(&bdev->bd_list);
#ifdef CONFIG_SYSFS
INIT_LIST_HEAD(&bdev->bd_holder_list);
#endif
inode_init_once(&ei->vfs_inode);
/* Initialize mutex for freeze. */
mutex_init(&bdev->bd_fsfreeze_mutex);
}
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);
}
static const struct super_operations bdev_sops = {
.statfs = simple_statfs,
.alloc_inode = bdev_alloc_inode,
.destroy_inode = bdev_destroy_inode,
.drop_inode = generic_delete_inode,
.clear_inode = bdev_clear_inode,
};
static int bd_get_sb(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data, struct vfsmount *mnt)
{
return get_sb_pseudo(fs_type, "bdev:", &bdev_sops, 0x62646576, mnt);
}
static struct file_system_type bd_type = {
.name = "bdev",
.get_sb = bd_get_sb,
.kill_sb = kill_anon_super,
};
struct super_block *blockdev_superblock __read_mostly;
void __init bdev_cache_init(void)
{
int err;
struct vfsmount *bd_mnt;
bdev_cachep = kmem_cache_create("bdev_cache", sizeof(struct bdev_inode),
0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
SLAB_MEM_SPREAD|SLAB_PANIC),
init_once);
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");
/*
* This vfsmount structure is only used to obtain the
* blockdev_superblock, so tell kmemleak not to report it.
*/
kmemleak_not_leak(bd_mnt);
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;
inode = iget5_locked(blockdev_superblock, hash(dev),
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);
/**
* bdgrab -- Grab a reference to an already referenced block device
* @bdev: Block device to grab a reference to.
*/
struct block_device *bdgrab(struct block_device *bdev)
{
atomic_inc(&bdev->bd_inode->i_count);
return bdev;
}
long nr_blockdev_pages(void)
{
struct block_device *bdev;
long ret = 0;
spin_lock(&bdev_lock);
list_for_each_entry(bdev, &all_bdevs, bd_list) {
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;
spin_lock(&bdev_lock);
bdev = inode->i_bdev;
if (bdev) {
atomic_inc(&bdev->bd_inode->i_count);
spin_unlock(&bdev_lock);
return bdev;
}
spin_unlock(&bdev_lock);
bdev = bdget(inode->i_rdev);
if (bdev) {
spin_lock(&bdev_lock);
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);
}
spin_unlock(&bdev_lock);
}
return bdev;
}
/* Call when you free inode */
void bd_forget(struct inode *inode)
{
struct block_device *bdev = NULL;
spin_lock(&bdev_lock);
if (inode->i_bdev) {
if (!sb_is_blkdev_sb(inode->i_sb))
bdev = inode->i_bdev;
__bd_forget(inode);
}
spin_unlock(&bdev_lock);
if (bdev)
iput(bdev->bd_inode);
}
/**
* bd_may_claim - test whether a block device can be claimed
* @bdev: block device of interest
* @whole: whole block device containing @bdev, may equal @bdev
* @holder: holder trying to claim @bdev
*
* Test whther @bdev can be claimed by @holder.
*
* CONTEXT:
* spin_lock(&bdev_lock).
*
* RETURNS:
* %true if @bdev can be claimed, %false otherwise.
*/
static bool bd_may_claim(struct block_device *bdev, struct block_device *whole,
void *holder)
{
if (bdev->bd_holder == holder)
return true; /* already a holder */
else if (bdev->bd_holder != NULL)
return false; /* held by someone else */
else if (bdev->bd_contains == bdev)
return true; /* is a whole device which isn't held */
else if (whole->bd_holder == bd_claim)
return true; /* is a partition of a device that is being partitioned */
else if (whole->bd_holder != NULL)
return false; /* is a partition of a held device */
else
return true; /* is a partition of an un-held device */
}
/**
* bd_prepare_to_claim - prepare to claim a block device
* @bdev: block device of interest
* @whole: the whole device containing @bdev, may equal @bdev
* @holder: holder trying to claim @bdev
*
* Prepare to claim @bdev. This function fails if @bdev is already
* claimed by another holder and waits if another claiming is in
* progress. This function doesn't actually claim. On successful
* return, the caller has ownership of bd_claiming and bd_holder[s].
*
* CONTEXT:
* spin_lock(&bdev_lock). Might release bdev_lock, sleep and regrab
* it multiple times.
*
* RETURNS:
* 0 if @bdev can be claimed, -EBUSY otherwise.
*/
static int bd_prepare_to_claim(struct block_device *bdev,
struct block_device *whole, void *holder)
{
retry:
/* if someone else claimed, fail */
if (!bd_may_claim(bdev, whole, holder))
return -EBUSY;
/* if claiming is already in progress, wait for it to finish */
if (whole->bd_claiming) {
wait_queue_head_t *wq = bit_waitqueue(&whole->bd_claiming, 0);
DEFINE_WAIT(wait);
prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE);
spin_unlock(&bdev_lock);
schedule();
finish_wait(wq, &wait);
spin_lock(&bdev_lock);
goto retry;
}
/* yay, all mine */
return 0;
}
/**
* bd_start_claiming - start claiming a block device
* @bdev: block device of interest
* @holder: holder trying to claim @bdev
*
* @bdev is about to be opened exclusively. Check @bdev can be opened
* exclusively and mark that an exclusive open is in progress. Each
* successful call to this function must be matched with a call to
* either bd_finish_claiming() or bd_abort_claiming() (which do not
* fail).
*
* This function is used to gain exclusive access to the block device
* without actually causing other exclusive open attempts to fail. It
* should be used when the open sequence itself requires exclusive
* access but may subsequently fail.
*
* CONTEXT:
* Might sleep.
*
* RETURNS:
* Pointer to the block device containing @bdev on success, ERR_PTR()
* value on failure.
*/
static struct block_device *bd_start_claiming(struct block_device *bdev,
void *holder)
{
struct gendisk *disk;
struct block_device *whole;
int partno, err;
might_sleep();
/*
* @bdev might not have been initialized properly yet, look up
* and grab the outer block device the hard way.
*/
disk = get_gendisk(bdev->bd_dev, &partno);
if (!disk)
return ERR_PTR(-ENXIO);
whole = bdget_disk(disk, 0);
module_put(disk->fops->owner);
put_disk(disk);
if (!whole)
return ERR_PTR(-ENOMEM);
/* prepare to claim, if successful, mark claiming in progress */
spin_lock(&bdev_lock);
err = bd_prepare_to_claim(bdev, whole, holder);
if (err == 0) {
whole->bd_claiming = holder;
spin_unlock(&bdev_lock);
return whole;
} else {
spin_unlock(&bdev_lock);
bdput(whole);
return ERR_PTR(err);
}
}
/* releases bdev_lock */
static void __bd_abort_claiming(struct block_device *whole, void *holder)
{
BUG_ON(whole->bd_claiming != holder);
whole->bd_claiming = NULL;
wake_up_bit(&whole->bd_claiming, 0);
spin_unlock(&bdev_lock);
bdput(whole);
}
/**
* bd_abort_claiming - abort claiming a block device
* @whole: whole block device returned by bd_start_claiming()
* @holder: holder trying to claim @bdev
*
* Abort a claiming block started by bd_start_claiming(). Note that
* @whole is not the block device to be claimed but the whole device
* returned by bd_start_claiming().
*
* CONTEXT:
* Grabs and releases bdev_lock.
*/
static void bd_abort_claiming(struct block_device *whole, void *holder)
{
spin_lock(&bdev_lock);
__bd_abort_claiming(whole, holder); /* releases bdev_lock */
}
/* increment holders when we have a legitimate claim. requires bdev_lock */
static void __bd_claim(struct block_device *bdev, struct block_device *whole,
void *holder)
{
/* 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
*/
whole->bd_holders++;
whole->bd_holder = bd_claim;
bdev->bd_holders++;
bdev->bd_holder = holder;
}
/**
* bd_finish_claiming - finish claiming a block device
* @bdev: block device of interest (passed to bd_start_claiming())
* @whole: whole block device returned by bd_start_claiming()
* @holder: holder trying to claim @bdev
*
* Finish a claiming block started by bd_start_claiming().
*
* CONTEXT:
* Grabs and releases bdev_lock.
*/
static void bd_finish_claiming(struct block_device *bdev,
struct block_device *whole, void *holder)
{
spin_lock(&bdev_lock);
BUG_ON(!bd_may_claim(bdev, whole, holder));
__bd_claim(bdev, whole, holder);
__bd_abort_claiming(whole, holder); /* not actually an abort */
}
/**
* bd_claim - claim a block device
* @bdev: block device to claim
* @holder: holder trying to claim @bdev
*
* Try to claim @bdev which must have been opened successfully.
*
* CONTEXT:
* Might sleep.
*
* RETURNS:
* 0 if successful, -EBUSY if @bdev is already claimed.
*/
int bd_claim(struct block_device *bdev, void *holder)
{
struct block_device *whole = bdev->bd_contains;
int res;
might_sleep();
spin_lock(&bdev_lock);
res = bd_prepare_to_claim(bdev, whole, holder);
if (res == 0)
__bd_claim(bdev, whole, 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);
#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
*/
static int add_symlink(struct kobject *from, struct kobject *to)
{
if (!from || !to)
return 0;
return sysfs_create_link(from, to, kobject_name(to));
}
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;
bo->sdev = kobject_get(&part_to_dev(bdev->bd_part)->kobj);
if (!bo->sdev)
goto fail_put_hdev;
bo->hdir = kobject_get(bdev->bd_part->holder_dir);
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);
}
/**
* 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.
*/
static struct bd_holder *find_bd_holder(struct block_device *bdev,
struct bd_holder *bo)
{
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;
}
/**
* 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()
*
* Add @bo to @bdev->bd_holder_list, create symlinks.
*
* Returns 0 if symlinks are created.
* Returns -ve if something fails.
*/
static int add_bd_holder(struct block_device *bdev, struct bd_holder *bo)
{
int err;
if (!bo)
return -EINVAL;
if (!bd_holder_grab_dirs(bdev, bo))
return -EBUSY;
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;
}
list_add_tail(&bo->list, &bdev->bd_holder_list);
return 0;
}
/**
* 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)
{
int err;
struct bd_holder *bo, *found;
if (!kobj)
return -EINVAL;
bo = alloc_bd_holder(kobj);
if (!bo)
return -ENOMEM;
mutex_lock(&bdev->bd_mutex);
err = bd_claim(bdev, holder);
if (err)
goto fail;
found = find_bd_holder(bdev, bo);
if (found)
goto fail;
err = add_bd_holder(bdev, bo);
if (err)
bd_release(bdev);
else
bo = NULL;
fail:
mutex_unlock(&bdev->bd_mutex);
free_bd_holder(bo);
return err;
}
/**
* 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;
mutex_lock(&bdev->bd_mutex);
bd_release(bdev);
free_bd_holder(del_bd_holder(bdev, kobj));
mutex_unlock(&bdev->bd_mutex);
}
/**
* 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
/*
* 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.
*/
struct block_device *open_by_devnum(dev_t dev, fmode_t mode)
{
struct block_device *bdev = bdget(dev);
int err = -ENOMEM;
if (bdev)
err = blkdev_get(bdev, mode);
return err ? ERR_PTR(err) : bdev;
}
EXPORT_SYMBOL(open_by_devnum);
/**
* 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;
}
/**
* check_disk_size_change - checks for disk size change and adjusts bdev size.
* @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);
flush_disk(bdev);
}
}
EXPORT_SYMBOL(check_disk_size_change);
/**
* revalidate_disk - wrapper for lower-level driver's revalidate_disk call-back
* @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)
{
struct block_device *bdev;
int ret = 0;
if (disk->fops->revalidate_disk)
ret = disk->fops->revalidate_disk(disk);
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);
return ret;
}
EXPORT_SYMBOL(revalidate_disk);
/*
* 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;
const struct block_device_operations *bdops = disk->fops;
if (!bdops->media_changed)
return 0;
if (!bdops->media_changed(bdev->bd_disk))
return 0;
flush_disk(bdev);
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_logical_block_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);
static int __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part);
/*
* bd_mutex locking:
*
* mutex_lock(part->bd_mutex)
* mutex_lock_nested(whole->bd_mutex, 1)
*/
static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
{
struct gendisk *disk;
int ret;
int partno;
int perm = 0;
if (mode & FMODE_READ)
perm |= MAY_READ;
if (mode & FMODE_WRITE)
perm |= MAY_WRITE;
/*
* hooks: /n/, see "layering violations".
*/
ret = devcgroup_inode_permission(bdev->bd_inode, perm);
if (ret != 0) {
bdput(bdev);
return ret;
}
lock_kernel();
restart:
ret = -ENXIO;
disk = get_gendisk(bdev->bd_dev, &partno);
if (!disk)
goto out_unlock_kernel;
mutex_lock_nested(&bdev->bd_mutex, for_part);
if (!bdev->bd_openers) {
bdev->bd_disk = disk;
bdev->bd_contains = bdev;
if (!partno) {
struct backing_dev_info *bdi;
ret = -ENXIO;
bdev->bd_part = disk_get_part(disk, partno);
if (!bdev->bd_part)
goto out_clear;
if (disk->fops->open) {
ret = disk->fops->open(bdev, mode);
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;
}
if (ret)
goto out_clear;
}
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)
goto out_clear;
BUG_ON(for_part);
ret = __blkdev_get(whole, mode, 1);
if (ret)
goto out_clear;
bdev->bd_contains = whole;
bdev->bd_inode->i_data.backing_dev_info =
whole->bd_inode->i_data.backing_dev_info;
bdev->bd_part = disk_get_part(disk, partno);
if (!(disk->flags & GENHD_FL_UP) ||
!bdev->bd_part || !bdev->bd_part->nr_sects) {
ret = -ENXIO;
goto out_clear;
}
bd_set_size(bdev, (loff_t)bdev->bd_part->nr_sects << 9);
}
} else {
module_put(disk->fops->owner);
put_disk(disk);
disk = NULL;
if (bdev->bd_contains == bdev) {
if (bdev->bd_disk->fops->open) {
ret = bdev->bd_disk->fops->open(bdev, mode);
if (ret)
goto out_unlock_bdev;
}
if (bdev->bd_invalidated)
rescan_partitions(bdev->bd_disk, bdev);
}
}
bdev->bd_openers++;
if (for_part)
bdev->bd_part_count++;
mutex_unlock(&bdev->bd_mutex);
unlock_kernel();
return 0;
out_clear:
disk_put_part(bdev->bd_part);
bdev->bd_disk = NULL;
bdev->bd_part = NULL;
bdev->bd_inode->i_data.backing_dev_info = &default_backing_dev_info;
if (bdev != bdev->bd_contains)
__blkdev_put(bdev->bd_contains, mode, 1);
bdev->bd_contains = NULL;
out_unlock_bdev:
mutex_unlock(&bdev->bd_mutex);
out_unlock_kernel:
unlock_kernel();
if (disk)
module_put(disk->fops->owner);
put_disk(disk);
bdput(bdev);
return ret;
}
int blkdev_get(struct block_device *bdev, fmode_t mode)
{
return __blkdev_get(bdev, mode, 0);
}
EXPORT_SYMBOL(blkdev_get);
static int blkdev_open(struct inode * inode, struct file * filp)
{
struct block_device *whole = NULL;
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;
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;
bdev = bd_acquire(inode);
if (bdev == NULL)
return -ENOMEM;
if (filp->f_mode & FMODE_EXCL) {
whole = bd_start_claiming(bdev, filp);
if (IS_ERR(whole)) {
bdput(bdev);
return PTR_ERR(whole);
}
}
filp->f_mapping = bdev->bd_inode->i_mapping;
res = blkdev_get(bdev, filp->f_mode);
if (whole) {
if (res == 0)
bd_finish_claiming(bdev, whole, filp);
else
bd_abort_claiming(whole, filp);
}
return res;
}
static int __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part)
{
int ret = 0;
struct gendisk *disk = bdev->bd_disk;
struct block_device *victim = NULL;
mutex_lock_nested(&bdev->bd_mutex, for_part);
lock_kernel();
if (for_part)
bdev->bd_part_count--;
if (!--bdev->bd_openers) {
sync_blockdev(bdev);
kill_bdev(bdev);
}
if (bdev->bd_contains == bdev) {
if (disk->fops->release)
ret = disk->fops->release(disk, mode);
}
if (!bdev->bd_openers) {
struct module *owner = disk->fops->owner;
put_disk(disk);
module_put(owner);
disk_put_part(bdev->bd_part);
bdev->bd_part = NULL;
bdev->bd_disk = NULL;
bdev->bd_inode->i_data.backing_dev_info = &default_backing_dev_info;
if (bdev != bdev->bd_contains)
victim = bdev->bd_contains;
bdev->bd_contains = NULL;
}
unlock_kernel();
mutex_unlock(&bdev->bd_mutex);
bdput(bdev);
if (victim)
__blkdev_put(victim, mode, 1);
return ret;
}
int blkdev_put(struct block_device *bdev, fmode_t mode)
{
return __blkdev_put(bdev, mode, 0);
}
EXPORT_SYMBOL(blkdev_put);
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);
return blkdev_put(bdev, filp->f_mode);
}
static long block_ioctl(struct file *file, unsigned cmd, unsigned long arg)
{
struct block_device *bdev = I_BDEV(file->f_mapping->host);
fmode_t mode = file->f_mode;
/*
* O_NDELAY can be altered using fcntl(.., F_SETFL, ..), so we have
* to updated it before every ioctl.
*/
if (file->f_flags & O_NDELAY)
mode |= FMODE_NDELAY;
else
mode &= ~FMODE_NDELAY;
return blkdev_ioctl(bdev, mode, cmd, arg);
}
/*
* Write data to the block device. Only intended for the block device itself
* and the raw driver which basically is a fake block device.
*
* Does not take i_mutex for the write and thus is not for general purpose
* use.
*/
ssize_t blkdev_aio_write(struct kiocb *iocb, const struct iovec *iov,
unsigned long nr_segs, loff_t pos)
{
struct file *file = iocb->ki_filp;
ssize_t ret;
BUG_ON(iocb->ki_pos != pos);
ret = __generic_file_aio_write(iocb, iov, nr_segs, &iocb->ki_pos);
if (ret > 0 || ret == -EIOCBQUEUED) {
ssize_t err;
err = generic_write_sync(file, pos, ret);
if (err < 0 && ret > 0)
ret = err;
}
return ret;
}
EXPORT_SYMBOL_GPL(blkdev_aio_write);
/*
* 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);
}
static const struct address_space_operations def_blk_aops = {
.readpage = blkdev_readpage,
.writepage = blkdev_writepage,
.sync_page = block_sync_page,
.write_begin = blkdev_write_begin,
.write_end = blkdev_write_end,
.writepages = generic_writepages,
.releasepage = blkdev_releasepage,
.direct_IO = blkdev_direct_IO,
};
const struct file_operations def_blk_fops = {
.open = blkdev_open,
.release = blkdev_close,
.llseek = block_llseek,
.read = do_sync_read,
.write = do_sync_write,
.aio_read = generic_file_aio_read,
.aio_write = blkdev_aio_write,
.mmap = generic_file_mmap,
.fsync = blkdev_fsync,
.unlocked_ioctl = block_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = compat_blkdev_ioctl,
#endif
.splice_read = generic_file_splice_read,
.splice_write = generic_file_splice_write,
};
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);
res = blkdev_ioctl(bdev, 0, cmd, arg);
set_fs(old_fs);
return res;
}
EXPORT_SYMBOL(ioctl_by_bdev);
/**
* lookup_bdev - lookup a struct block_device by name
* @pathname: special file representing the block device
*
* Get a reference to the blockdevice at @pathname in the current
* namespace if possible and return it. Return ERR_PTR(error)
* otherwise.
*/
struct block_device *lookup_bdev(const char *pathname)
{
struct block_device *bdev;
struct inode *inode;
struct path path;
int error;
if (!pathname || !*pathname)
return ERR_PTR(-EINVAL);
error = kern_path(pathname, LOOKUP_FOLLOW, &path);
if (error)
return ERR_PTR(error);
inode = path.dentry->d_inode;
error = -ENOTBLK;
if (!S_ISBLK(inode->i_mode))
goto fail;
error = -EACCES;
if (path.mnt->mnt_flags & MNT_NODEV)
goto fail;
error = -ENOMEM;
bdev = bd_acquire(inode);
if (!bdev)
goto fail;
out:
path_put(&path);
return bdev;
fail:
bdev = ERR_PTR(error);
goto out;
}
EXPORT_SYMBOL(lookup_bdev);
/**
* open_bdev_exclusive - open a block device by name and set it up for use
*
* @path: special file representing the block device
* @mode: FMODE_... combination to pass be used
* @holder: owner for exclusion
*
* Open the blockdevice described by the special file at @path, claim it
* for the @holder.
*/
struct block_device *open_bdev_exclusive(const char *path, fmode_t mode, void *holder)
{
struct block_device *bdev, *whole;
int error;
bdev = lookup_bdev(path);
if (IS_ERR(bdev))
return bdev;
whole = bd_start_claiming(bdev, holder);
if (IS_ERR(whole)) {
bdput(bdev);
return whole;
}
error = blkdev_get(bdev, mode);
if (error)
goto out_abort_claiming;
error = -EACCES;
if ((mode & FMODE_WRITE) && bdev_read_only(bdev))
goto out_blkdev_put;
bd_finish_claiming(bdev, whole, holder);
return bdev;
out_blkdev_put:
blkdev_put(bdev, mode);
out_abort_claiming:
bd_abort_claiming(whole, holder);
return ERR_PTR(error);
}
EXPORT_SYMBOL(open_bdev_exclusive);
/**
* close_bdev_exclusive - close a blockdevice opened by open_bdev_exclusive()
*
* @bdev: blockdevice to close
* @mode: mode, must match that used to open.
*
* This is the counterpart to open_bdev_exclusive().
*/
void close_bdev_exclusive(struct block_device *bdev, fmode_t mode)
{
bd_release(bdev);
blkdev_put(bdev, mode);
}
EXPORT_SYMBOL(close_bdev_exclusive);
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);
}
invalidate_bdev(bdev);
return res;
}
EXPORT_SYMBOL(__invalidate_device);