Commit d4d77629 authored by Tejun Heo's avatar Tejun Heo
Browse files

block: clean up blkdev_get() wrappers and their users 



After recent blkdev_get() modifications, open_by_devnum() and
open_bdev_exclusive() are simple wrappers around blkdev_get().
Replace them with blkdev_get_by_dev() and blkdev_get_by_path().

blkdev_get_by_dev() is identical to open_by_devnum().
blkdev_get_by_path() is slightly different in that it doesn't
automatically add %FMODE_EXCL to @mode.

All users are converted.  Most conversions are mechanical and don't
introduce any behavior difference.  There are several exceptions.

* btrfs now sets FMODE_EXCL in btrfs_device->mode, so there's no
  reason to OR it explicitly on blkdev_put().

* gfs2, nilfs2 and the generic mount_bdev() now set FMODE_EXCL in
  sb->s_mode.

* With the above changes, sb->s_mode now always should contain
  FMODE_EXCL.  WARN_ON_ONCE() added to kill_block_super() to detect
  errors.

The new blkdev_get_*() functions are with proper docbook comments.
While at it, add function description to blkdev_get() too.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Cc: Philipp Reisner <philipp.reisner@linbit.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Joern Engel <joern@lazybastard.org>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Jan Kara <jack@suse.cz>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp>
Cc: reiserfs-devel@vger.kernel.org
Cc: xfs-masters@oss.sgi.com
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
parent 75f1dc0d

drivers/block/drbd/drbd_nl.c

+6 −6
Original line number Diff line number Diff line
@@ -902,8 +902,8 @@ static int drbd_nl_disk_conf(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp 
		}

	}



	bdev = open_bdev_exclusive(nbc->dc.backing_dev,

				   FMODE_READ | FMODE_WRITE, mdev);

	bdev = blkdev_get_by_path(nbc->dc.backing_dev,

				  FMODE_READ | FMODE_WRITE | FMODE_EXCL, mdev);

	if (IS_ERR(bdev)) {

		dev_err(DEV, "open(\"%s\") failed with %ld\n", nbc->dc.backing_dev,

			PTR_ERR(bdev));
@@ -920,8 +920,8 @@ static int drbd_nl_disk_conf(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp 
	 * should check it for you already; but if you don't, or

	 * someone fooled it, we need to double check here)

	 */

	bdev = open_bdev_exclusive(nbc->dc.meta_dev,

				   FMODE_READ | FMODE_WRITE,

	bdev = blkdev_get_by_path(nbc->dc.meta_dev,

				  FMODE_READ | FMODE_WRITE | FMODE_EXCL,

				  (nbc->dc.meta_dev_idx < 0) ?

				  (void *)mdev : (void *)drbd_m_holder);

	if (IS_ERR(bdev)) {

drivers/md/dm-table.c

+1 −1
Original line number Diff line number Diff line
@@ -325,7 +325,7 @@ static int open_dev(struct dm_dev_internal *d, dev_t dev, 


	BUG_ON(d->dm_dev.bdev);



	bdev = open_by_devnum(dev, d->dm_dev.mode | FMODE_EXCL, _claim_ptr);

	bdev = blkdev_get_by_dev(dev, d->dm_dev.mode | FMODE_EXCL, _claim_ptr);

	if (IS_ERR(bdev))

		return PTR_ERR(bdev);

drivers/md/md.c

+2 −2
Original line number Diff line number Diff line
@@ -1934,7 +1934,7 @@ static int lock_rdev(mdk_rdev_t *rdev, dev_t dev, int shared) 
	struct block_device *bdev;

	char b[BDEVNAME_SIZE];



	bdev = open_by_devnum(dev, FMODE_READ|FMODE_WRITE|FMODE_EXCL,

	bdev = blkdev_get_by_dev(dev, FMODE_READ|FMODE_WRITE|FMODE_EXCL,

				 shared ? (mdk_rdev_t *)lock_rdev : rdev);

	if (IS_ERR(bdev)) {

		printk(KERN_ERR "md: could not open %s.\n",

drivers/mtd/devices/block2mtd.c

+2 −2
Original line number Diff line number Diff line
@@ -247,7 +247,7 @@ static struct block2mtd_dev *add_device(char *devname, int erase_size) 
		return NULL;



	/* Get a handle on the device */

	bdev = open_bdev_exclusive(devname, mode, dev);

	bdev = blkdev_get_by_path(devname, mode, dev);

#ifndef MODULE

	if (IS_ERR(bdev)) {
@@ -256,7 +256,7 @@ static struct block2mtd_dev *add_device(char *devname, int erase_size) 


		dev_t devt = name_to_dev_t(devname);

		if (devt)

			bdev = open_by_devnum(devt, mode, dev);

			bdev = blkdev_get_by_dev(devt, mode, dev);

	}

#endif

fs/block_dev.c

+93 −46
Original line number Diff line number Diff line
@@ -854,24 +854,6 @@ static inline void bd_unlink_disk_holder(struct block_device *bdev) 
{ }

#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, void *holder)

{

	struct block_device *bdev = bdget(dev);

	int err = -ENOMEM;

	if (bdev)

		err = blkdev_get(bdev, mode, holder);

	return err ? ERR_PTR(err) : bdev;

}



EXPORT_SYMBOL(open_by_devnum);



/**

 * flush_disk - invalidates all buffer-cache entries on a disk

 *
@@ -1132,6 +1114,25 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part) 
	return ret;

}



/**

 * blkdev_get - open a block device

 * @bdev: block_device to open

 * @mode: FMODE_* mask

 * @holder: exclusive holder identifier

 *

 * Open @bdev with @mode.  If @mode includes %FMODE_EXCL, @bdev is

 * open with exclusive access.  Specifying %FMODE_EXCL with %NULL

 * @holder is invalid.  Exclusive opens may nest for the same @holder.

 *

 * On success, the reference count of @bdev is unchanged.  On failure,

 * @bdev is put.

 *

 * CONTEXT:

 * Might sleep.

 *

 * RETURNS:

 * 0 on success, -errno on failure.

 */

int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder)

{

	struct block_device *whole = NULL;
@@ -1186,6 +1187,80 @@ int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder) 
}

EXPORT_SYMBOL(blkdev_get);



/**

 * blkdev_get_by_path - open a block device by name

 * @path: path to the block device to open

 * @mode: FMODE_* mask

 * @holder: exclusive holder identifier

 *

 * Open the blockdevice described by the device file at @path.  @mode

 * and @holder are identical to blkdev_get().

 *

 * On success, the returned block_device has reference count of one.

 *

 * CONTEXT:

 * Might sleep.

 *

 * RETURNS:

 * Pointer to block_device on success, ERR_PTR(-errno) on failure.

 */

struct block_device *blkdev_get_by_path(const char *path, fmode_t mode,

					void *holder)

{

	struct block_device *bdev;

	int err;



	bdev = lookup_bdev(path);

	if (IS_ERR(bdev))

		return bdev;



	err = blkdev_get(bdev, mode, holder);

	if (err)

		return ERR_PTR(err);



	return bdev;

}

EXPORT_SYMBOL(blkdev_get_by_path);



/**

 * blkdev_get_by_dev - open a block device by device number

 * @dev: device number of block device to open

 * @mode: FMODE_* mask

 * @holder: exclusive holder identifier

 *

 * Open the blockdevice described by device number @dev.  @mode and

 * @holder are identical to blkdev_get().

 *

 * 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.

 *

 * On success, the returned block_device has reference count of one.

 *

 * CONTEXT:

 * Might sleep.

 *

 * RETURNS:

 * Pointer to block_device on success, ERR_PTR(-errno) on failure.

 */

struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder)

{

	struct block_device *bdev;

	int err;



	bdev = bdget(dev);

	if (!bdev)

		return ERR_PTR(-ENOMEM);



	err = blkdev_get(bdev, mode, holder);

	if (err)

		return ERR_PTR(err);



	return bdev;

}

EXPORT_SYMBOL(blkdev_get_by_dev);



static int blkdev_open(struct inode * inode, struct file * filp)

{

	struct block_device *bdev;
@@ -1436,34 +1511,6 @@ fail: 
}

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;

	int error;



	bdev = lookup_bdev(path);

	if (IS_ERR(bdev))

		return bdev;



	error = blkdev_get(bdev, mode | FMODE_EXCL, holder);

	if (error)

		return ERR_PTR(error);



	return bdev;

}



EXPORT_SYMBOL(open_bdev_exclusive);



int __invalidate_device(struct block_device *bdev)

{

	struct super_block *sb = get_super(bdev);

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