smb: client: fix return value of parse_dfs_referrals()

Return -ENOENT in parse_dfs_referrals() when server returns no targets
for a referral request as specified in

  MS-DFSC 3.1.5.4.3 Receiving a Root Referral Response or Link
  Referral Response:

    > If the referral request is successful, but the NumberOfReferrals
    > field in the referral header (as specified in section 2.2.4) is
    > 0, the DFS server could not find suitable targets to return to
    > the client.  In this case, the client MUST fail the original I/O
    > operation with STATUS_OBJECT_PATH_NOT_FOUND.

Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

Author: Paulo Alcantara

fs/smb/client/misc.c

@@ -909,9 +909,9 @@ parse_dfs_referrals(struct get_dfs_referral_rsp *rsp, u32 rsp_size,
 	*num_of_nodes = le16_to_cpu(rsp->NumberOfReferrals);
 
 	if (*num_of_nodes < 1) {
-		cifs_dbg(VFS, "num_referrals: must be at least > 0, but we get num_referrals = %d\n",
-			 *num_of_nodes);
-		rc = -EINVAL;
+		cifs_dbg(VFS | ONCE, "%s: [path=%s] num_referrals must be at least > 0, but we got %d\n",
+			 __func__, searchName, *num_of_nodes);
+		rc = -ENOENT;
 		goto parse_DFS_referrals_exit;
 	}
 

fs/smb/client/smb2ops.c

@@ -3007,9 +3007,9 @@ smb2_get_dfs_refer(const unsigned int xid, struct cifs_ses *ses,
 				 num_of_nodes, target_nodes,
 				 nls_codepage, remap, search_name,
 				 true /* is_unicode */);
-	if (rc) {
-		cifs_tcon_dbg(VFS, "parse error in %s rc=%d\n", __func__, rc);
-		goto out;
+	if (rc && rc != -ENOENT) {
+		cifs_tcon_dbg(VFS, "%s: failed to parse DFS referral %s: %d\n",
+			      __func__, search_name, rc);
 	}
 
  out: