cifs: Identify a connection by a conn_id.

Introduced a new field conn_id in TCP_Server_Info structure.
This is a non-persistent unique identifier maintained by the client
for a connection to a file server. For this, a global counter named
tcpSesNextId is maintained. On allocating a new TCP_Server_Info,
this counter is incremented and assigned.

Changed the dynamic tracepoints related to reconnects and
crediting to be more informative (with conn_id printed).
Debugging a crediting issue helped me understand the
important things to print here.

Always call dynamic tracepoints outside the scope of spinlocks.
To do this, copy out the credits and in_flight fields of the
server struct before dropping the lock.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 3152601a608b..0aa2c3c871c9 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -577,6 +577,7 @@ inc_rfc1001_len(void *buf, int count)
 struct TCP_Server_Info {
 	struct list_head tcp_ses_list;
 	struct list_head smb_ses_list;
+	__u64 conn_id; /* connection identifier (useful for debugging) */
 	int srv_count; /* reference counter */
 	/* 15 character server name + 0x20 16th byte indicating type = srv */
 	char server_RFC1001_name[RFC1001_NAME_LEN_WITH_NULL];
@@ -1846,6 +1847,7 @@ GLOBAL_EXTERN spinlock_t GlobalMid_Lock;  /* protects above & list operations */
  */
 GLOBAL_EXTERN atomic_t sesInfoAllocCount;
 GLOBAL_EXTERN atomic_t tconInfoAllocCount;
+GLOBAL_EXTERN atomic_t tcpSesNextId;
 GLOBAL_EXTERN atomic_t tcpSesAllocCount;
 GLOBAL_EXTERN atomic_t tcpSesReconnectCount;
 GLOBAL_EXTERN atomic_t tconInfoReconnectCount;