smb3: add dynamic trace points for socket connection

In debugging user problems with ip address/DNS issues with
smb3 mounts, we sometimes needed additional info on the hostname
and ip address.

Add two tracepoints, one to show socket connection success
and one for failures to connect to the socket.

Sample output:
      mount.cifs-14551   [005] .....  7636.547906: smb3_connect_done: conn_id=0x1 server=localhost addr=127.0.0.1:445
      mount.cifs-14558   [004] .....  7642.405413: smb3_connect_done: conn_id=0x2 server=smfrench.file.core.windows.net addr=52.239.158.232:445
      mount.cifs-14741   [005] .....  7818.490716: smb3_connect_done: conn_id=0x3 server=::1 addr=[::1]:445/0%0
      mount.cifs-14810   [000] .....  7966.380337: smb3_connect_err: rc=-101 conn_id=0x4 server=::2 addr=[::2]:445/0%0
      mount.cifs-14810   [000] .....  7966.380356: smb3_connect_err: rc=-101 conn_id=0x4 server=::2 addr=[::2]:139/0%0
      mount.cifs-14818   [003] .....  7986.771992: smb3_connect_done: conn_id=0x5 server=127.0.0.9 addr=127.0.0.9:445
      mount.cifs-14825   [008] .....  8008.178109: smb3_connect_err: rc=-115 conn_id=0x6 server=124.23.0.9 addr=124.23.0.9:445
      mount.cifs-14825   [008] .....  8013.298085: smb3_connect_err: rc=-115 conn_id=0x6 server=124.23.0.9 addr=124.23.0.9:139
           cifsd-14553   [006] .....  8036.735615: smb3_reconnect: conn_id=0x1 server=localhost current_mid=32
           cifsd-14743   [010] .....  8036.735644: smb3_reconnect: conn_id=0x3 server=::1 current_mid=29
           cifsd-14743   [010] .....  8039.921740: smb3_connect_err: rc=-111 conn_id=0x3 server=::1 addr=[::1]:445/0%0
           cifsd-14553   [008] .....  8042.993894: smb3_connect_err: rc=-111 conn_id=0x1 server=localhost addr=127.0.0.1:445
           cifsd-14743   [010] .....  8042.993894: smb3_connect_err: rc=-111 conn_id=0x3 server=::1 addr=[::1]:445/0%0
           cifsd-14553   [008] .....  8046.065824: smb3_connect_err: rc=-111 conn_id=0x1 server=localhost addr=127.0.0.1:445
           cifsd-14743   [010] .....  8046.065824: smb3_connect_err: rc=-111 conn_id=0x3 server=::1 addr=[::1]:445/0%0
           cifsd-14553   [008] .....  8049.137796: smb3_connect_done: conn_id=0x1 server=localhost addr=127.0.0.1:445
           cifsd-14743   [010] .....  8049.137796: smb3_connect_done: conn_id=0x3 server=::1 addr=[::1]:445/0%0

Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/cifs/connect.c

@@ -2649,11 +2649,12 @@ generic_ip_connect(struct TCP_Server_Info *server)
 		rc = 0;
 	if (rc < 0) {
 		cifs_dbg(FYI, "Error %d connecting to server\n", rc);
+		trace_smb3_connect_err(server->hostname, server->conn_id, &server->dstaddr, rc);
 		sock_release(socket);
 		server->ssocket = NULL;
 		return rc;
 	}
-
+	trace_smb3_connect_done(server->hostname, server->conn_id, &server->dstaddr);
 	if (sport == htons(RFC1001_PORT))
 		rc = ip_rfc1001_connect(server);
 

fs/cifs/trace.h

@@ -11,6 +11,8 @@
 #define _CIFS_TRACE_H
 
 #include <linux/tracepoint.h>
+#include <linux/net.h>
+#include <linux/inet.h>
 
 /*
  * Please use this 3-part article as a reference for writing new tracepoints:
@@ -854,6 +856,75 @@ DEFINE_EVENT(smb3_lease_err_class, smb3_##name,  \
 
 DEFINE_SMB3_LEASE_ERR_EVENT(lease_err);
 
+DECLARE_EVENT_CLASS(smb3_connect_class,
+	TP_PROTO(char *hostname,
+		__u64 conn_id,
+		const struct __kernel_sockaddr_storage *dst_addr),
+	TP_ARGS(hostname, conn_id, dst_addr),
+	TP_STRUCT__entry(
+		__string(hostname, hostname)
+		__field(__u64, conn_id)
+		__array(__u8, dst_addr, sizeof(struct sockaddr_storage))
+	),
+	TP_fast_assign(
+		struct sockaddr_storage *pss = NULL;
+
+		__entry->conn_id = conn_id;
+		pss = (struct sockaddr_storage *)__entry->dst_addr;
+		*pss = *dst_addr;
+		__assign_str(hostname, hostname);
+	),
+	TP_printk("conn_id=0x%llx server=%s addr=%pISpsfc",
+		__entry->conn_id,
+		__get_str(hostname),
+		__entry->dst_addr)
+)
+
+#define DEFINE_SMB3_CONNECT_EVENT(name)        \
+DEFINE_EVENT(smb3_connect_class, smb3_##name,  \
+	TP_PROTO(char *hostname,		\
+		__u64 conn_id,			\
+		const struct __kernel_sockaddr_storage *addr),	\
+	TP_ARGS(hostname, conn_id, addr))
+
+DEFINE_SMB3_CONNECT_EVENT(connect_done);
+
+DECLARE_EVENT_CLASS(smb3_connect_err_class,
+	TP_PROTO(char *hostname, __u64 conn_id,
+		const struct __kernel_sockaddr_storage *dst_addr, int rc),
+	TP_ARGS(hostname, conn_id, dst_addr, rc),
+	TP_STRUCT__entry(
+		__string(hostname, hostname)
+		__field(__u64, conn_id)
+		__array(__u8, dst_addr, sizeof(struct sockaddr_storage))
+		__field(int, rc)
+	),
+	TP_fast_assign(
+		struct sockaddr_storage *pss = NULL;
+
+		__entry->conn_id = conn_id;
+		__entry->rc = rc;
+		pss = (struct sockaddr_storage *)__entry->dst_addr;
+		*pss = *dst_addr;
+		__assign_str(hostname, hostname);
+	),
+	TP_printk("rc=%d conn_id=0x%llx server=%s addr=%pISpsfc",
+		__entry->rc,
+		__entry->conn_id,
+		__get_str(hostname),
+		__entry->dst_addr)
+)
+
+#define DEFINE_SMB3_CONNECT_ERR_EVENT(name)        \
+DEFINE_EVENT(smb3_connect_err_class, smb3_##name,  \
+	TP_PROTO(char *hostname,		\
+		__u64 conn_id,			\
+		const struct __kernel_sockaddr_storage *addr,	\
+		int rc),			\
+	TP_ARGS(hostname, conn_id, addr, rc))
+
+DEFINE_SMB3_CONNECT_ERR_EVENT(connect_err);
+
 DECLARE_EVENT_CLASS(smb3_reconnect_class,
 	TP_PROTO(__u64	currmid,
 		__u64 conn_id,