On 12/17/2010 08:38 PM, Jeff Layton wrote:
> If the server isn't responding to echoes, we don't want to leave tasks
> hung waiting for it to reply. At that point, we'll want to reconnect
> so that soft mounts can return an error to userspace quickly.
>
> If the client hasn't received a reply after 3 echo intervals, assume
> that the transport is down and attempt to reconnect the socket.
>
> Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
> ---
> fs/cifs/connect.c | 23 +++++++++++++++++++----
> 1 files changed, 19 insertions(+), 4 deletions(-)
>
> diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
> index 20f6eda..2ad3c67 100644
> --- a/fs/cifs/connect.c
> +++ b/fs/cifs/connect.c
> @@ -55,6 +55,9 @@
> /* SMB echo "timeout" -- FIXME: tunable? */
> #define SMB_ECHO_INTERVAL (60 * HZ)
>
> +/* reconnect if no response from server in this time period */
> +#define UNRESPONSIVE_SERVER_TIMEOUT (5 * SMB_ECHO_INTERVAL)
> +
It's not clear to me why is this timeout is set to be
5 * SMB_ECHO_INTERVAL?
> extern void SMBNTencrypt(unsigned char *passwd, unsigned char *c8,
> unsigned char *p24);
>
> @@ -186,6 +189,7 @@ cifs_reconnect(struct TCP_Server_Info *server)
> kfree(server->session_key.response);
> server->session_key.response = NULL;
> server->session_key.len = 0;
> + server->lstrp = jiffies;
> mutex_unlock(&server->srv_mutex);
>
> /*
> @@ -423,7 +427,19 @@ cifs_demultiplex_thread(struct TCP_Server_Info *server)
> smb_msg.msg_control = NULL;
> smb_msg.msg_controllen = 0;
> pdu_length = 4; /* enough to get RFC1001 header */
> +
> incomplete_rcv:
> + if (time_after(jiffies,
> + server->lstrp + UNRESPONSIVE_SERVER_TIMEOUT)) {
> + cERROR(1, "Server %s has not responded in %d seconds. "
> + "Reconnecting...", server->hostname,
> + UNRESPONSIVE_SERVER_TIMEOUT / HZ);
> + cifs_reconnect(server);
> + csocket = server->ssocket;
> + wake_up(&server->response_q);
> + continue;
> + }
> +
> length =
> kernel_recvmsg(csocket, &smb_msg,
> &iov, 1, pdu_length, 0 /* BB other flags? */);
> @@ -584,6 +600,8 @@ incomplete_rcv:
> }
>
> mid_entry = NULL;
> + server->lstrp = jiffies;
> +
> spin_lock(&GlobalMid_Lock);
> list_for_each_safe(tmp, tmp2, &server->pending_mid_q) {
> mid_entry = list_entry(tmp, struct mid_q_entry, qhead);
> @@ -632,10 +650,6 @@ multi_t2_fnd:
> #ifdef CONFIG_CIFS_STATS2
> mid_entry->when_received = jiffies;
> #endif
> - /* so we do not time out requests to server
> - which is still responding (since server could
> - be busy but not dead) */
> - server->lstrp = jiffies;
> break;
> }
> mid_entry = NULL;
> @@ -1685,6 +1699,7 @@ cifs_get_tcp_session(struct smb_vol *volume_info)
> volume_info->target_rfc1001_name, RFC1001_NAME_LEN_WITH_NULL);
> tcp_ses->session_estab = false;
> tcp_ses->sequence_number = 0;
> + tcp_ses->lstrp = jiffies;
> INIT_LIST_HEAD(&tcp_ses->tcp_ses_list);
> INIT_LIST_HEAD(&tcp_ses->smb_ses_list);
> INIT_DELAYED_WORK(&tcp_ses->echo, cifs_echo_request);
--
Suresh Jayaraman
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