ceph: choose auth MDS for getxattr with the Xs caps

And for the 'Xs' caps for getxattr we will also choose the auth MDS,
because the MDS side code is buggy due to setxattr won't notify the
replica MDSes when the values changed and the replica MDS will return
the old values. Though we will fix it in MDS code, but this still
makes sense for old ceph.

Link: https://tracker.ceph.com/issues/55331
Signed-off-by: Xiubo Li <[e-mail]>
Reviewed-by: Ilya Dryomov <[e-mail]>
Signed-off-by: Ilya Dryomov <[e-mail]>

fs/ceph/inode.c

···
 	 *
 	 * This cost much when doing the Locker state transition and
 	 * usually will need to revoke caps from clients.
+	 *
+	 * And for the 'Xs' caps for getxattr we will also choose the
+	 * auth MDS, because the MDS side code is buggy due to setxattr
+	 * won't notify the replica MDSes when the values changed and
+	 * the replica MDS will return the old values. Though we will
+	 * fix it in MDS code, but this still makes sense for old ceph.
 	 */
 	if (((mask & CEPH_CAP_ANY_SHARED) && (issued & CEPH_CAP_ANY_EXCL))
-	    || (mask & CEPH_STAT_RSTAT))
+	    || (mask & (CEPH_STAT_RSTAT | CEPH_STAT_CAP_XATTR)))
 		return USE_AUTH_MDS;
 	else
 		return USE_ANY_MDS;