[CIFS] Return better error when server requires signing but client forbids

Signed-off-by: Steve French <sfrench@us.ibm.com>
diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index d22af63..2b2d4fe 100644
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -663,10 +663,12 @@
 		/* MUST_SIGN already includes the MAY_SIGN FLAG
 		   so if this is zero it means that signing is disabled */
 		cFYI(1, ("Signing disabled"));
-		if (server->secMode & SECMODE_SIGN_REQUIRED)
+		if (server->secMode & SECMODE_SIGN_REQUIRED) {
 			cERROR(1, ("Server requires "
 				   "packet signing to be enabled in "
 				   "/proc/fs/cifs/SecurityFlags."));
+			rc = -EOPNOTSUPP;
+		}
 		server->secMode &=
 			~(SECMODE_SIGN_ENABLED | SECMODE_SIGN_REQUIRED);
 	} else if ((secFlags & CIFSSEC_MUST_SIGN) == CIFSSEC_MUST_SIGN) {