Commit 8d945b59 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Christian Brauner
Browse files

xfs: drop s_umount over opening the log and RT devices 



Just like get_tree_bdev needs to drop s_umount when opening the main
device, we need to do the same for the xfs log and RT devices to avoid a
potential lock order reversal with s_unmount for the mark_dead path.

It might be preferable to just drop s_umount over ->fill_super entirely,
but that will require a fairly massive audit first, so we'll do the easy
version here first.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatar"Darrick J. Wong" <djwong@kernel.org>
Message-Id: <20230802154131.2221419-12-hch@lst.de>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent 8bed1783

fs/xfs/xfs_super.c

+14 −4
Original line number Diff line number Diff line
@@ -462,17 +462,24 @@ STATIC int 
xfs_open_devices(

	struct xfs_mount	*mp)

{

	struct block_device	*ddev = mp->m_super->s_bdev;

	struct super_block	*sb = mp->m_super;

	struct block_device	*ddev = sb->s_bdev;

	struct block_device	*logdev = NULL, *rtdev = NULL;

	int			error;



	/*

	 * blkdev_put() can't be called under s_umount, see the comment

	 * in get_tree_bdev() for more details

	 */

	up_write(&sb->s_umount);



	/*

	 * Open real time and log devices - order is important.

	 */

	if (mp->m_logname) {

		error = xfs_blkdev_get(mp, mp->m_logname, &logdev);

		if (error)

			return error;

			goto out_relock;

	}



	if (mp->m_rtname) {
@@ -510,7 +517,10 @@ xfs_open_devices( 
		mp->m_logdev_targp = mp->m_ddev_targp;

	}



	return 0;

	error = 0;

out_relock:

	down_write(&sb->s_umount);

	return error;



 out_free_rtdev_targ:

	if (mp->m_rtdev_targp)
@@ -523,7 +533,7 @@ xfs_open_devices( 
 out_close_logdev:

	if (logdev && logdev != ddev)

		blkdev_put(logdev, mp);

	return error;

	goto out_relock;

}



/*