2010/12/27 Jeff Layton <jlayton@xxxxxxxxxx>:
> 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 a specified number of echo
> intervals, assume that the transport is down and attempt to reconnect
> the socket.
>
> The number of echo_intervals to wait before attempting to reconnect is
> tunable via a module parameter. Setting it to 0, means that the client
> will never attempt to reconnect. The default is 5.
>
> Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
> ---
> fs/cifs/cifsfs.c | 5 +++++
> fs/cifs/cifsglob.h | 3 +++
> fs/cifs/connect.c | 21 +++++++++++++++++----
> 3 files changed, 25 insertions(+), 4 deletions(-)
>
> diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
> index e0fabbf..27fa0a2 100644
> --- a/fs/cifs/cifsfs.c
> +++ b/fs/cifs/cifsfs.c
> @@ -80,6 +80,11 @@ bool sign_zero_copy = false;
> module_param(sign_zero_copy, bool, 0644);
> MODULE_PARM_DESC(sign_zero_copy, "Don't copy pages on write with signing "
> "enabled. Default: N");
> +unsigned short echo_retries = 5;
> +module_param(echo_retries, ushort, 0644);
> +MODULE_PARM_DESC(echo_retries, "Number of echo attempts before giving up and "
> + "reconnecting server. Default: 5. 0 means "
> + "never reconnect.");
> extern mempool_t *cifs_sm_req_poolp;
> extern mempool_t *cifs_req_poolp;
> extern mempool_t *cifs_mid_poolp;
> diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
> index 64d69f9..1dc74f4 100644
> --- a/fs/cifs/cifsglob.h
> +++ b/fs/cifs/cifsglob.h
> @@ -799,6 +799,9 @@ GLOBAL_EXTERN unsigned int cifs_min_small; /* min size of small buf pool */
> GLOBAL_EXTERN unsigned int cifs_max_pending; /* MAX requests at once to server*/
> GLOBAL_EXTERN bool sign_zero_copy; /* don't copy written pages with signing */
>
> +/* reconnect after this many failed echo attempts */
> +GLOBAL_EXTERN unsigned short echo_retries;
> +
> void cifs_oplock_break(struct work_struct *work);
> void cifs_oplock_break_get(struct cifsFileInfo *cfile);
> void cifs_oplock_break_put(struct cifsFileInfo *cfile);
> diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
> index 57187c6..0e7ae1e 100644
> --- a/fs/cifs/connect.c
> +++ b/fs/cifs/connect.c
> @@ -186,6 +186,7 @@ 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);
>
> /* mark submitted MIDs for retry and issue callback */
> @@ -420,7 +421,20 @@ 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 (echo_retries > 0 &&
> + time_after(jiffies, server->lstrp +
> + (echo_retries * SMB_ECHO_INTERVAL))) {
> + cERROR(1, "Server %s has not responded in %d seconds. "
> + "Reconnecting...", server->hostname,
> + (echo_retries * SMB_ECHO_INTERVAL / 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? */);
> @@ -581,6 +595,8 @@ 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);
> @@ -629,10 +645,6 @@ 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;
> @@ -1683,6 +1695,7 @@ 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);
> --
> 1.7.3.4
>
> --
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>
Reviewed-by: Pavel Shilovsky <piastryyy@xxxxxxxxx>
--
Best regards,
Pavel Shilovsky.
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