[CIFS] Do not send SMBEcho requests on new sockets until SMBNegotiate

In order to determine whether an SMBEcho request can be sent
we need to know that the socket is established (server tcpStatus == CifsGood)
AND that an SMB NegotiateProtocol has been sent (server maxBuf != 0).
Without the second check we can send an Echo request during reconnection
before the server can accept it.

CC: JG <jg@cms.ac>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>

diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index edd5b29b53c9a354ac6c0a8d934a793c0221cea0..1ab33eb71d95d95dbf4f424c0e95a691feec7e64 100644 (file)
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -188,6 +188,8 @@ struct TCP_Server_Info {
        /* multiplexed reads or writes */
        unsigned int maxBuf;    /* maxBuf specifies the maximum */
        /* message size the server can send or receive for non-raw SMBs */
+       /* maxBuf is returned by SMB NegotiateProtocol so maxBuf is only 0 */
+       /* when socket is setup (and during reconnect) before NegProt sent */
        unsigned int max_rw;    /* maxRw specifies the maximum */
        /* message size the server can send or receive for */
        /* SMB_COM_WRITE_RAW or SMB_COM_READ_RAW. */

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 257b6d895e20d519adcb04ff84de9a3cc5cd93c2..10011e99b34dc6412c8f0e3d15263547a870da93 100644 (file)
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -341,7 +341,7 @@ cifs_echo_request(struct work_struct *work)
         * We cannot send an echo until the NEGOTIATE_PROTOCOL request is done.
         * Also, no need to ping if we got a response recently
         */
-       if (server->tcpStatus != CifsGood ||
+       if ((server->tcpStatus != CifsGood) || (server->maxBuf == 0) ||
            time_before(jiffies, server->lstrp + SMB_ECHO_INTERVAL - HZ))
                goto requeue_echo;