ext4: avoid possible double brelse() in add_new_gdb() on error path

commit 4f32c38b4662312dd3c5f113d8bdd459887fb773 upstream.

Fixes: b4097142 ("ext4: add error checking to calls to ...")
Reported-by: NVasily Averin <vvs@virtuozzo.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org # 2.6.38
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

fs/ext4/resize.c

@@ -871,6 +871,7 @@ static int add_new_gdb(handle_t *handle, struct inode *inode,
 	err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
 	if (unlikely(err)) {
 		ext4_std_error(sb, err);
+		iloc.bh = NULL;
 		goto exit_inode;
 	}
 	brelse(dind);