[PATCH] [v2]cifs: Make echo interval tunable

[Sachin Prabhu <sprabhu-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>]

Currently the echo interval is set to 60 seconds using a macro. This
setting determines the interval at which echo requests are sent to the
server on an idling connection. This setting also affects the time
required for a connection to an unresponsive server to timeout.

Making this setting a tunable allows users to control the echo interval
times as well as control the time after which the connecting to an
unresponsive server times out.

Signed-off-by: Sachin Prabhu <sprabhu-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
---
 fs/cifs/cifsfs.c   |  2 ++
 fs/cifs/cifsglob.h |  8 ++++++--
 fs/cifs/connect.c  | 33 +++++++++++++++++++++++++++------
 3 files changed, 35 insertions(+), 8 deletions(-)

diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index cbc0f4b..eab2de6 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -507,6 +507,8 @@ cifs_show_options(struct seq_file *s, struct dentry *root)
 
 	seq_printf(s, ",rsize=%u", cifs_sb->rsize);
 	seq_printf(s, ",wsize=%u", cifs_sb->wsize);
+	seq_printf(s, ",echo_interval=%lu",
+			tcon->ses->server->echo_interval / HZ);
 	/* convert actimeo and display it in seconds */
 	seq_printf(s, ",actimeo=%lu", cifs_sb->actimeo / HZ);
 
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 2b510c5..9d14926 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -70,8 +70,10 @@
 #define SERVER_NAME_LENGTH 40
 #define SERVER_NAME_LEN_WITH_NULL     (SERVER_NAME_LENGTH + 1)
 
-/* SMB echo "timeout" -- FIXME: tunable? */
-#define SMB_ECHO_INTERVAL (60 * HZ)
+/* echo interval in seconds */
+#define SMB_ECHO_INTERVAL_MIN 1
+#define SMB_ECHO_INTERVAL_MAX 600
+#define SMB_ECHO_INTERVAL_DEFAULT 60
 
 #include "cifspdu.h"
 
@@ -507,6 +509,7 @@ struct smb_vol {
 	struct sockaddr_storage dstaddr; /* destination address */
 	struct sockaddr_storage srcaddr; /* allow binding to a local IP */
 	struct nls_table *local_nls;
+	unsigned int echo_interval; /* echo interval in secs */
 };
 
 #define CIFS_MOUNT_MASK (CIFS_MOUNT_NO_PERM | CIFS_MOUNT_SET_UID | \
@@ -628,6 +631,7 @@ struct TCP_Server_Info {
 	unsigned int	max_read;
 	unsigned int	max_write;
 #endif /* CONFIG_CIFS_SMB2 */
+	unsigned long echo_interval;
 };
 
 static inline unsigned int
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index ecb0803..3b44e9e 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -95,6 +95,7 @@ enum {
 	Opt_cruid, Opt_gid, Opt_file_mode,
 	Opt_dirmode, Opt_port,
 	Opt_rsize, Opt_wsize, Opt_actimeo,
+	Opt_echo_interval,
 
 	/* Mount options which take string value */
 	Opt_user, Opt_pass, Opt_ip,
@@ -188,6 +189,7 @@ static const match_table_t cifs_mount_option_tokens = {
 	{ Opt_rsize, "rsize=%s" },
 	{ Opt_wsize, "wsize=%s" },
 	{ Opt_actimeo, "actimeo=%s" },
+	{ Opt_echo_interval, "echo_interval=%s" },
 
 	{ Opt_blank_user, "user=" },
 	{ Opt_blank_user, "username=" },
@@ -418,6 +420,7 @@ cifs_echo_request(struct work_struct *work)
 	int rc;
 	struct TCP_Server_Info *server = container_of(work,
 					struct TCP_Server_Info, echo.work);
+	unsigned long echo_interval = server->echo_interval;
 
 	/*
 	 * We cannot send an echo if it is disabled or until the
@@ -427,7 +430,7 @@ cifs_echo_request(struct work_struct *work)
 	 */
 	if (!server->ops->need_neg || server->ops->need_neg(server) ||
 	    (server->ops->can_echo && !server->ops->can_echo(server)) ||
-	    time_before(jiffies, server->lstrp + SMB_ECHO_INTERVAL - HZ))
+	    time_before(jiffies, server->lstrp + echo_interval - HZ))
 		goto requeue_echo;
 
 	rc = server->ops->echo ? server->ops->echo(server) : -ENOSYS;
@@ -436,7 +439,7 @@ cifs_echo_request(struct work_struct *work)
 			 server->hostname);
 
 requeue_echo:
-	queue_delayed_work(cifsiod_wq, &server->echo, SMB_ECHO_INTERVAL);
+	queue_delayed_work(cifsiod_wq, &server->echo, echo_interval);
 }
 
 static bool
@@ -487,9 +490,9 @@ server_unresponsive(struct TCP_Server_Info *server)
 	 *     a response in >60s.
 	 */
 	if (server->tcpStatus == CifsGood &&
-	    time_after(jiffies, server->lstrp + 2 * SMB_ECHO_INTERVAL)) {
-		cifs_dbg(VFS, "Server %s has not responded in %d seconds. Reconnecting...\n",
-			 server->hostname, (2 * SMB_ECHO_INTERVAL) / HZ);
+	    time_after(jiffies, server->lstrp + 2 * server->echo_interval)) {
+		cifs_dbg(VFS, "Server %s has not responded in %lu seconds. Reconnecting...\n",
+			 server->hostname, (2 * server->echo_interval) / HZ);
 		cifs_reconnect(server);
 		wake_up(&server->response_q);
 		return true;
@@ -1624,6 +1627,14 @@ cifs_parse_mount_options(const char *mountdata, const char *devname,
 				goto cifs_parse_mount_err;
 			}
 			break;
+		case Opt_echo_interval:
+			if (get_option_ul(args, &option)) {
+				cifs_dbg(VFS, "%s: Invalid echo interval value\n",
+					 __func__);
+				goto cifs_parse_mount_err;
+			}
+			vol->echo_interval = option;
+			break;
 
 		/* String Arguments */
 
@@ -2089,6 +2100,9 @@ static int match_server(struct TCP_Server_Info *server, struct smb_vol *vol)
 	if (!match_security(server, vol))
 		return 0;
 
+	if (server->echo_interval != vol->echo_interval)
+		return 0;
+
 	return 1;
 }
 
@@ -2208,6 +2222,13 @@ cifs_get_tcp_session(struct smb_vol *volume_info)
 	tcp_ses->tcpStatus = CifsNew;
 	++tcp_ses->srv_count;
 
+	/* echo interval should be between 10 and 120 secs */
+	if (volume_info->echo_interval > SMB_ECHO_INTERVAL_MIN ||
+		volume_info->echo_interval < SMB_ECHO_INTERVAL_MAX)
+		tcp_ses->echo_interval = volume_info->echo_interval * HZ;
+	else
+		tcp_ses->echo_interval = SMB_ECHO_INTERVAL_DEFAULT * HZ;
+
 	rc = ip_connect(tcp_ses);
 	if (rc < 0) {
 		cifs_dbg(VFS, "Error connecting to socket. Aborting operation.\n");
@@ -2237,7 +2258,7 @@ cifs_get_tcp_session(struct smb_vol *volume_info)
 	cifs_fscache_get_client_cookie(tcp_ses);
 
 	/* queue echo request delayed work */
-	queue_delayed_work(cifsiod_wq, &tcp_ses->echo, SMB_ECHO_INTERVAL);
+	queue_delayed_work(cifsiod_wq, &tcp_ses->echo, tcp_ses->echo_interval);
 
 	return tcp_ses;
 
-- 
2.5.0