ceph: fix a memory leak on cap_auths in MDS client

The cap_auths that are allocated during an MDS session opening are never
released, causing a memory leak detected by kmemleak.  Fix this by freeing
the memory allocated when shutting down the MDS client.

Fixes: 1d17de9 ("ceph: save cap_auths in MDS client when session is opened")
Signed-off-by: Luis Henriques (SUSE) <luis.henriques@linux.dev>
Reviewed-by: Xiubo Li <xiubli@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

Author: Luis Henriques (SUSE)

fs/ceph/mds_client.c

@@ -6016,6 +6016,18 @@ static void ceph_mdsc_stop(struct ceph_mds_client *mdsc)
 		ceph_mdsmap_destroy(mdsc->mdsmap);
 	kfree(mdsc->sessions);
 	ceph_caps_finalize(mdsc);
+
+	if (mdsc->s_cap_auths) {
+		int i;
+
+		for (i = 0; i < mdsc->s_cap_auths_num; i++) {
+			kfree(mdsc->s_cap_auths[i].match.gids);
+			kfree(mdsc->s_cap_auths[i].match.path);
+			kfree(mdsc->s_cap_auths[i].match.fs_name);
+		}
+		kfree(mdsc->s_cap_auths);
+	}
+
 	ceph_pool_perm_destroy(mdsc);
 }