cifs: return -ENODATA when deleting an xattr that does not exist

BUGZILLA: https://bugzilla.kernel.org/show_bug.cgi?id=202007

When deleting an xattr/EA:
SMB2/3 servers will return SUCCESS when clients delete non-existing EAs.
This means that we need to first QUERY the server and check if the EA
exists or not so that we can return -ENODATA correctly when this happens.

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/cifs/smb2ops.c

@@ -940,6 +940,16 @@ smb2_set_ea(const unsigned int xid, struct cifs_tcon *tcon,
 	resp_buftype[0] = resp_buftype[1] = resp_buftype[2] = CIFS_NO_BUFFER;
 	memset(rsp_iov, 0, sizeof(rsp_iov));
 
+	if (ses->server->ops->query_all_EAs) {
+		if (!ea_value) {
+			rc = ses->server->ops->query_all_EAs(xid, tcon, path,
+							     ea_name, NULL, 0,
+							     cifs_sb);
+			if (rc == -ENODATA)
+				goto sea_exit;
+		}
+	}
+
 	/* Open */
 	memset(&open_iov, 0, sizeof(open_iov));
 	rqst[0].rq_iov = open_iov;