Commit 9c09a7cf authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Christian Brauner
Browse files

fs: stop using get_super in fs_mark_dead 



fs_mark_dead currently uses get_super to find the superblock for the
block device that is going away.  This means it is limited to the
main device stored in sb->s_dev, leading to a lot of code duplication
for file systems that can use multiple block devices.

Now that the holder for all block devices used by file systems is set
to the super_block, we can instead look at that holder and then check
if the file system is born and active, so do that instead.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Reviewed-by: default avatarChristian Brauner <brauner@kernel.org>
Message-Id: <20230802154131.2221419-8-hch@lst.de>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent 2ea6f689

fs/super.c

+26 −4
Original line number Diff line number Diff line
@@ -1209,17 +1209,39 @@ int get_tree_keyed(struct fs_context *fc, 
EXPORT_SYMBOL(get_tree_keyed);



#ifdef CONFIG_BLOCK

/*

 * Lock a super block that the callers holds a reference to.

 *

 * The caller needs to ensure that the super_block isn't being freed while

 * calling this function, e.g. by holding a lock over the call to this function

 * and the place that clears the pointer to the superblock used by this function

 * before freeing the superblock.

 */

static bool lock_active_super(struct super_block *sb)

{

	down_read(&sb->s_umount);

	if (!sb->s_root ||

	    (sb->s_flags & (SB_ACTIVE | SB_BORN)) != (SB_ACTIVE | SB_BORN)) {

		up_read(&sb->s_umount);

		return false;

	}

	return true;

}



static void fs_mark_dead(struct block_device *bdev)

{

	struct super_block *sb;

	struct super_block *sb = bdev->bd_holder;



	sb = get_super(bdev);

	if (!sb)

	/* bd_holder_lock ensures that the sb isn't freed */

	lockdep_assert_held(&bdev->bd_holder_lock);



	if (!lock_active_super(sb))

		return;



	if (sb->s_op->shutdown)

		sb->s_op->shutdown(sb);

	drop_super(sb);



	up_read(&sb->s_umount);

}



static const struct blk_holder_ops fs_holder_ops = {