Fix btrfs b0rkage

Buggered-in: 76dda93c6ae2 ("Btrfs: add snapshot/subvolume destroy
ioctl")

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: Chris Mason <chris.mason@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/btrfs/export.c

@@ -166,7 +166,7 @@ static struct dentry *btrfs_fh_to_dentry(struct super_block *sb, struct fid *fh,
 static struct dentry *btrfs_get_parent(struct dentry *child)
 {
 	struct inode *dir = child->d_inode;
-	static struct dentry *dentry;
+	struct dentry *dentry;
 	struct btrfs_root *root = BTRFS_I(dir)->root;
 	struct btrfs_path *path;
 	struct extent_buffer *leaf;