GFS2: put glock reference in error patch of read_rindex_entry

This patch fixes the error path of function read_rindex_entry
so that it correctly gives up its glock reference in cases where
there is a race to re-read the rindex after gfs2_grow.
Signed-off-by: NBob Peterson <rpeterso@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

fs/gfs2/rgrp.c

@@ -640,6 +640,7 @@ static int read_rindex_entry(struct gfs2_inode *ip,
 		return 0;
 
 	error = 0; /* someone else read in the rgrp; free it and ignore it */
+	gfs2_glock_put(rgd->rd_gl);
 
 fail:
 	kfree(rgd->rd_bits);