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

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) <pc@manguebit.org>
Acked-by: Meetakshi Setiya <msetiya@microsoft.com>
Signed-off-by: zhangjian <zhangjian496@huawei.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

diff --git a/fs/smb/client/connect.c b/fs/smb/client/connect.c
index c4fb80b37738d388379976765580dcfd439e6aa4..c48869c29e154ac97416c53f62bdeaa5b3b0495f 100644 (file)
--- a/fs/smb/client/connect.c
+++ b/fs/smb/client/connect.c
@@ -4199,6 +4199,7 @@ retry:
                return 0;
        }
 
+       server->lstrp = jiffies;
        server->tcpStatus = CifsInNegotiate;
        spin_unlock(&server->srv_lock);