cifs: eliminate some more premature cifsd exits

If the tcpStatus is still CifsNew, the main cifs_demultiplex_loop can
break out prematurely in some cases. This is wrong as we will almost
always have other structures with pointers to the TCP_Server_Info. If
the main loop breaks under any other condition other than tcpStatus ==
CifsExiting, then it'll face a use-after-free situation.

I don't see any reason to treat a CifsNew tcpStatus differently than
CifsGood. I believe we'll still want to attempt to reconnect in either
case. What should happen in those situations is that the MIDs get marked
as MID_RETRY_NEEDED. This will make CIFSSMBNegotiate return -EAGAIN, and
then the caller can retry the whole thing on a newly reconnected socket.
If that fails again in the same way, the caller of cifs_get_smb_ses
should tear down the TCP_Server_Info struct.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 5f68b96..5fde83f 100644 (file)
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -416,14 +416,6 @@ incomplete_rcv:
                        } else
                                continue;
                } else if (length <= 0) {
-                       if (server->tcpStatus == CifsNew) {
-                               cFYI(1, "tcp session abend after SMBnegprot");
-                               /* some servers kill the TCP session rather than
-                                  returning an SMB negprot error, in which
-                                  case reconnecting here is not going to help,
-                                  and so simply return error to mount */
-                               break;
-                       }
                        cFYI(1, "Reconnect after unexpected peek error %d",
                                length);
                        cifs_reconnect(server);
@@ -464,27 +456,18 @@ incomplete_rcv:
                           an error on SMB negprot response */
                        cFYI(1, "Negative RFC1002 Session Response Error 0x%x)",
                                pdu_length);
-                       if (server->tcpStatus == CifsNew) {
-                               /* if nack on negprot (rather than
-                               ret of smb negprot error) reconnecting
-                               not going to help, ret error to mount */
-                               break;
-                       } else {
-                               /* give server a second to
-                               clean up before reconnect attempt */
-                               msleep(1000);
-                               /* always try 445 first on reconnect
-                               since we get NACK on some if we ever
-                               connected to port 139 (the NACK is
-                               since we do not begin with RFC1001
-                               session initialize frame) */
-                               server->addr.sockAddr.sin_port =
-                                       htons(CIFS_PORT);
-                               cifs_reconnect(server);
-                               csocket = server->ssocket;
-                               wake_up(&server->response_q);
-                               continue;
-                       }
+                       /* give server a second to clean up  */
+                       msleep(1000);
+                       /* always try 445 first on reconnect since we get NACK
+                        * on some if we ever connected to port 139 (the NACK
+                        * is since we do not begin with RFC1001 session
+                        * initialize frame)
+                        */
+                       server->addr.sockAddr.sin_port = htons(CIFS_PORT);
+                       cifs_reconnect(server);
+                       csocket = server->ssocket;
+                       wake_up(&server->response_q);
+                       continue;
                } else if (temp != (char) 0) {
                        cERROR(1, "Unknown RFC 1002 frame");
                        cifs_dump_mem(" Received Data: ", (char *)smb_buffer,