[CIFS] Do not set DFS flag on SMB2 open

If we would set SMB2_FLAGS_DFS_OPERATIONS on open we also would have
to pass the path on the Open SMB prefixed by \\server\share.
Not sure when we would need to do the augmented path (if ever) and
setting this flag breaks the SMB2 open operation since it is
illegal to send an empty path name (without \\server\share prefix)
when the DFS flag is set in the SMB open header. We could
consider setting the flag on all operations other than open
but it is safer to net set it for now.

Signed-off-by: Steve French <smfrench@gmail.com>

fs/cifs/smb2pdu.c

@@ -120,13 +120,20 @@ smb2_hdr_assemble(struct smb2_hdr *hdr, __le16 smb2_cmd /* command */ ,
 	/* Uid is not converted */
 	if (tcon->ses)
 		hdr->SessionId = tcon->ses->Suid;
-	/* BB check following DFS flags BB */
-	/* BB do we have to add check for SHI1005_FLAGS_DFS_ROOT too? */
-	if (tcon->share_flags & SHI1005_FLAGS_DFS)
-		hdr->Flags |= SMB2_FLAGS_DFS_OPERATIONS;
-	/* BB how does SMB2 do case sensitive? */
-	/* if (tcon->nocase)
-		hdr->Flags |= SMBFLG_CASELESS; */
+
+	/*
+	 * If we would set SMB2_FLAGS_DFS_OPERATIONS on open we also would have
+	 * to pass the path on the Open SMB prefixed by \\server\share.
+	 * Not sure when we would need to do the augmented path (if ever) and
+	 * setting this flag breaks the SMB2 open operation since it is
+	 * illegal to send an empty path name (without \\server\share prefix)
+	 * when the DFS flag is set in the SMB open header. We could
+	 * consider setting the flag on all operations other than open
+	 * but it is safer to net set it for now.
+	 */
+/*	if (tcon->share_flags & SHI1005_FLAGS_DFS)
+		hdr->Flags |= SMB2_FLAGS_DFS_OPERATIONS; */
+
 	if (tcon->ses && tcon->ses->server && tcon->ses->server->sign)
 		hdr->Flags |= SMB2_FLAGS_SIGNED;
 out: