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, 8 insertions, 2 deletions

diff --git a/fs/cifs/smb2transport.c b/fs/cifs/smb2transport.c
index c523617eade2..59c748ce872f 100644
--- a/fs/cifs/smb2transport.c
+++ b/fs/cifs/smb2transport.c
@@ -516,13 +516,19 @@ smb2_get_mid_entry(struct cifs_ses *ses, struct smb2_hdr *buf,
 		return -EAGAIN;
 	}
 
-	if (ses->status != CifsGood) {
-		/* check if SMB2 session is bad because we are setting it up */
+	if (ses->status == CifsNew) {
 		if ((buf->Command != SMB2_SESSION_SETUP) &&
 		    (buf->Command != SMB2_NEGOTIATE))
 			return -EAGAIN;
 		/* else ok - we are setting up session */
 	}
+
+	if (ses->status == CifsExiting) {
+		if (buf->Command != SMB2_LOGOFF)
+			return -EAGAIN;
+		/* else ok - we are shutting down the session */
+	}
+
 	*mid = smb2_mid_entry_alloc(buf, ses->server);
 	if (*mid == NULL)
 		return -ENOMEM;