smb: client: fix first command failure during re-negotiation

commit 34331d7beed7576acfc98e991c39738b96162499 upstream.

after fabc4ed200f9, server_unresponsive add a condition to check whether client
need to reconnect depending on server->lstrp. When client failed to reconnect
for some time and abort connection, server->lstrp is updated for the last time.
In the following scene, server->lstrp is too old. This cause next command
failure in re-negotiation rather than waiting for re-negotiation done.

1. mount -t cifs -o username=Everyone,echo_internal=10 //$server_ip/export /mnt
2. ssh $server_ip "echo b > /proc/sysrq-trigger &"
3. ls /mnt
4. sleep 21s
5. ssh $server_ip "service firewalld stop"
6. ls # return EHOSTDOWN

If the interval between 5 and 6 is too small, 6 may trigger sending negotiation
request. Before backgrounding cifsd thread try to receive negotiation response
from server in cifs_readv_from_socket, server_unresponsive may trigger
cifs_reconnect which cause 6 to be failed:

ls thread
----------------
  smb2_negotiate
    server->tcpStatus = CifsInNegotiate
    compound_send_recv
      wait_for_compound_request

cifsd thread
----------------
  cifs_readv_from_socket
    server_unresponsive
      server->tcpStatus == CifsInNegotiate && jiffies > server->lstrp + 20s
        cifs_reconnect
          cifs_abort_connection: mid_state = MID_RETRY_NEEDED

ls thread
----------------
      cifs_sync_mid_result return EAGAIN
  smb2_negotiate return EHOSTDOWN

Though server->lstrp means last server response time, it is updated in
cifs_abort_connection and cifs_get_tcp_session. We can also update server->lstrp
before switching into CifsInNegotiate state to avoid failure in 6.

Fixes: 7ccc1465465d ("smb: client: fix hang in wait_for_response() for negproto")
Acked-by: Paulo Alcantara (Red Hat) <[email protected]>
Acked-by: Meetakshi Setiya <[email protected]>
Signed-off-by: zhangjian <[email protected]>
Signed-off-by: Steve French <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: zhangjian

fs/smb/client/connect.c

@@ -4217,6 +4217,7 @@ cifs_negotiate_protocol(const unsigned int xid, struct cifs_ses *ses,
 		return 0;
 	}
 
+	server->lstrp = jiffies;
 	server->tcpStatus = CifsInNegotiate;
 	spin_unlock(&server->srv_lock);