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>

3 files changed, 37 insertions, 9 deletions

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index a279ffc0bc29..62a55147400a 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);
 }
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;
diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
index 0ee6d249ef6f..b37570952846 100644
--- a/fs/cifs/transport.c
+++ b/fs/cifs/transport.c
@@ -431,13 +431,20 @@ static int allocate_mid(struct cifs_ses *ses, struct smb_hdr *in_buf,
                 return -EAGAIN;
         }
 
-        if (ses->status != CifsGood) {
-                /* check if SMB session is bad because we are setting it up */
+        if (ses->status == CifsNew) {
                 if ((in_buf->Command != SMB_COM_SESSION_SETUP_ANDX) &&
                         (in_buf->Command != SMB_COM_NEGOTIATE))
                         return -EAGAIN;
                 /* else ok - we are setting up session */
         }
+
+        if (ses->status == CifsExiting) {
+                /* check if SMB session is bad because we are setting it up */
+                if (in_buf->Command != SMB_COM_LOGOFF_ANDX)
+                        return -EAGAIN;
+                /* else ok - we are shutting down session */
+        }
+
         *ppmidQ = AllocMidQEntry(in_buf, ses->server);
         if (*ppmidQ == NULL)
                 return -ENOMEM;