cifs: Send a logoff request before removing a smb session

Send a smb session logoff request before removing smb session off of the list.
On a signed smb session, remvoing a session off of the list before sending
a logoff request results in server returning an error for lack of
smb signature.

Never seen an error during smb logoff, so as per MS-SMB2 3.2.5.1,
not sure how an error during logoff should be retried. So for now,
if a server returns an error to a logoff request, log the error and
remove the session off of the list.

Signed-off-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>

1 files changed, 20 insertions, 5 deletions

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index a279ffc0bc2..62a55147400 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -2242,6 +2242,8 @@ cifs_find_smb_ses(struct TCP_Server_Info *server, struct smb_vol *vol)
 
 	spin_lock(&cifs_tcp_ses_lock);
 	list_for_each_entry(ses, &server->smb_ses_list, smb_ses_list) {
+		if (ses->status == CifsExiting)
+			continue;
 		if (!match_session(ses, vol))
 			continue;
 		++ses->ses_count;
@@ -2255,24 +2257,37 @@ cifs_find_smb_ses(struct TCP_Server_Info *server, struct smb_vol *vol)
 static void
 cifs_put_smb_ses(struct cifs_ses *ses)
 {
-	unsigned int xid;
+	unsigned int rc, xid;
 	struct TCP_Server_Info *server = ses->server;
 
 	cifs_dbg(FYI, "%s: ses_count=%d\n", __func__, ses->ses_count);
+
 	spin_lock(&cifs_tcp_ses_lock);
+	if (ses->status == CifsExiting) {
+		spin_unlock(&cifs_tcp_ses_lock);
+		return;
+	}
 	if (--ses->ses_count > 0) {
 		spin_unlock(&cifs_tcp_ses_lock);
 		return;
 	}
-
-	list_del_init(&ses->smb_ses_list);
+	if (ses->status == CifsGood)
+		ses->status = CifsExiting;
 	spin_unlock(&cifs_tcp_ses_lock);
 
-	if (ses->status == CifsGood && server->ops->logoff) {
+	if (ses->status == CifsExiting && server->ops->logoff) {
 		xid = get_xid();
-		server->ops->logoff(xid, ses);
+		rc = server->ops->logoff(xid, ses);
+		if (rc)
+			cifs_dbg(VFS, "%s: Session Logoff failure rc=%d\n",
+				__func__, rc);
 		_free_xid(xid);
 	}
+
+	spin_lock(&cifs_tcp_ses_lock);
+	list_del_init(&ses->smb_ses_list);
+	spin_unlock(&cifs_tcp_ses_lock);
+
 	sesInfoFree(ses);
 	cifs_put_tcp_session(server);
 }