smb3: track the instance of each session for debugging

Each time we reconnect to the same server, bump an instance
counter (and display in /proc/fs/cifs/DebugData) to make it
easier to debug.

Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>

4 files changed, 10 insertions, 4 deletions

diff --git a/fs/cifs/cifs_debug.c b/fs/cifs/cifs_debug.c
index 06576797cf31..3ae62ec74c8d 100644
--- a/fs/cifs/cifs_debug.c
+++ b/fs/cifs/cifs_debug.c
@@ -285,7 +285,7 @@ skip_rdma:
                         if ((ses->serverDomain == NULL) ||
                                 (ses->serverOS == NULL) ||
                                 (ses->serverNOS == NULL)) {
-                                seq_printf(m, "\n%d) Name: %s Uses: %d Capability: 0x%x\tSession Status: %d\t",
+                                seq_printf(m, "\n%d) Name: %s Uses: %d Capability: 0x%x\tSession Status: %d ",
                                         i, ses->serverName, ses->ses_count,
                                         ses->capabilities, ses->status);
                                 if (ses->session_flags & SMB2_SESSION_FLAG_IS_GUEST)
@@ -296,16 +296,18 @@ skip_rdma:
                                 seq_printf(m,
                                     "\n%d) Name: %s  Domain: %s Uses: %d OS:"
                                     " %s\n\tNOS: %s\tCapability: 0x%x\n\tSMB"
-                                    " session status: %d\t",
+                                    " session status: %d ",
                                 i, ses->serverName, ses->serverDomain,
                                 ses->ses_count, ses->serverOS, ses->serverNOS,
                                 ses->capabilities, ses->status);
                         }
                         if (server->rdma)
                                 seq_printf(m, "RDMA\n\t");
-                        seq_printf(m, "TCP status: %d\n\tLocal Users To "
+                        seq_printf(m, "TCP status: %d Instance: %d\n\tLocal Users To "
                                    "Server: %d SecMode: 0x%x Req On Wire: %d",
-                                   server->tcpStatus, server->srv_count,
+                                   server->tcpStatus,
+                                   server->reconnect_instance,
+                                   server->srv_count,
                                    server->sec_mode, in_flight(server));
 
 #ifdef CONFIG_CIFS_STATS2
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index d59588e4aeb4..b2f7cbd587f9 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -654,6 +654,7 @@ struct TCP_Server_Info {
         /* 16th byte of RFC1001 workstation name is always null */
         char workstation_RFC1001_name[RFC1001_NAME_LEN_WITH_NULL];
         __u32 sequence_number; /* for signing, protected by srv_mutex */
+        __u32 reconnect_instance; /* incremented on each reconnect */
         struct session_key session_key;
         unsigned long lstrp; /* when we got last response from this server */
         struct cifs_secmech secmech; /* crypto sec mech functs, descriptors */
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 52d71b64c0c6..106d3a85f77b 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -2396,6 +2396,7 @@ 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->reconnect_instance = 0;
         tcp_ses->lstrp = jiffies;
         spin_lock_init(&tcp_ses->req_lock);
         INIT_LIST_HEAD(&tcp_ses->tcp_ses_list);
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 11b4f397a713..41342a8dc53e 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -110,6 +110,8 @@ smb2_set_credits(struct TCP_Server_Info *server, const int val)
 {
         spin_lock(&server->req_lock);
         server->credits = val;
+        if (val == 1)
+                server->reconnect_instance++;
         spin_unlock(&server->req_lock);
 }