[SMB3] add reconnect tracepoints

From 745929a07ac8b076d139f4479cb16b2b460cd335 Mon Sep 17 00:00:00 2001
From: Steve French <stfrench@microsoft.com>
Date: Mon, 30 Jul 2018 19:23:09 -0500
Subject: [PATCH] smb3: add reconnect tracepoints

Add tracepoints for reconnecting an smb3 session

Example output (from trace-cmd) with the patch
(showing the session marked for reconnect, the stat failing, and then
the subsequent SMB3 commands after the server comes back up).
The "smb3_reconnect" event is the new one.

           cifsd-25993 [000] .... 29635.368265: smb3_reconnect: server=localhost current_mid=0x1e
            stat-26200 [001] .... 29638.516403: smb3_enter: 	cifs_revalidate_dentry_attr: xid=22
            stat-26200 [001] .... 29648.723296: smb3_exit_err: 	cifs_revalidate_dentry_attr: xid=22 rc=-112
     kworker/0:1-22830 [000] .... 29653.850947: smb3_cmd_done: 	sid=0x0 tid=0x0 cmd=0 mid=0
     kworker/0:1-22830 [000] .... 29653.851191: smb3_cmd_err: 	sid=0x8ae4683c tid=0x0 cmd=1 mid=1 status=0xc0000016 rc=-5
     kworker/0:1-22830 [000] .... 29653.855254: smb3_cmd_done: 	sid=0x8ae4683c tid=0x0 cmd=1 mid=2
     kworker/0:1-22830 [000] .... 29653.855482: smb3_cmd_done: 	sid=0x8ae4683c tid=0x8084f30d cmd=3 mid=3

Signed-off-by: Steve French <stfrench@microsoft.com>
---
 fs/cifs/connect.c   |  1 +
 fs/cifs/trace.h     | 26 ++++++++++++++++++++++++++
 fs/cifs/transport.c |  2 ++
 3 files changed, 29 insertions(+)

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 67f91a6313a0..d9bd10d295a9 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -348,6 +348,7 @@  cifs_reconnect(struct TCP_Server_Info *server)
 	server->max_read = 0;
 
 	cifs_dbg(FYI, "Reconnecting tcp session\n");
+	trace_smb3_reconnect(server->CurrentMid, server->hostname);
 
 	/* before reconnecting the tcp session, mark the smb session (uid)
 		and the tid bad so they are not used until reconnected */
diff --git a/fs/cifs/trace.h b/fs/cifs/trace.h
index 0fdf2f5c07ba..6b50b57e2416 100644
--- a/fs/cifs/trace.h
+++ b/fs/cifs/trace.h
@@ -423,6 +423,32 @@  DEFINE_EVENT(smb3_open_done_class, smb3_##name,  \
 DEFINE_SMB3_OPEN_DONE_EVENT(open_done);
 DEFINE_SMB3_OPEN_DONE_EVENT(posix_mkdir_done);
 
+DECLARE_EVENT_CLASS(smb3_reconnect_class,
+	TP_PROTO(__u64	currmid,
+		char *hostname),
+	TP_ARGS(currmid, hostname),
+	TP_STRUCT__entry(
+		__field(__u64, currmid)
+		__field(char *, hostname)
+	),
+	TP_fast_assign(
+		__entry->currmid = currmid;
+		__entry->hostname = hostname;
+	),
+	TP_printk("server=%s current_mid=0x%llx",
+		__entry->hostname,
+		__entry->currmid)
+)
+
+#define DEFINE_SMB3_RECONNECT_EVENT(name)        \
+DEFINE_EVENT(smb3_reconnect_class, smb3_##name,  \
+	TP_PROTO(__u64	currmid,		\
+		char *hostname),		\
+	TP_ARGS(currmid, hostname))
+
+DEFINE_SMB3_RECONNECT_EVENT(reconnect);
+DEFINE_SMB3_RECONNECT_EVENT(partial_send_reconnect);
+
 #endif /* _CIFS_TRACE_H */
 
 #undef TRACE_INCLUDE_PATH
diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
index 0f9156af5eb0..357d25351ffa 100644
--- a/fs/cifs/transport.c
+++ b/fs/cifs/transport.c
@@ -361,6 +361,8 @@  __smb_send_rqst(struct TCP_Server_Info *server, int num_rqst,
 		 * socket so the server throws away the partial SMB
 		 */
 		server->tcpStatus = CifsNeedReconnect;
+		trace_smb3_partial_send_reconnect(server->CurrentMid,
+						  server->hostname);
 	}
 smbd_done:
 	if (rc < 0 && rc != -EINTR)
-- 
2.17.1