cifs: Avoid umount hangs with smb2 when server is unresponsive

Do not send SMB2 Logoff command when reconnecting, the way smb1
code base works.

Also, no need to wait for a credit for an echo command when one is already
in flight.

Without these changes, umount command hangs if the server is unresponsive
e.g. hibernating.

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

diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index eba0efde66d70ae15974eef74b10ff6d83ca44d8..edccb5252462b6b465d3d71cb7d3de20e8d2be9a 100644 (file)
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -687,6 +687,10 @@ SMB2_logoff(const unsigned int xid, struct cifs_ses *ses)
        else
                return -EIO;
 
+       /* no need to send SMB logoff if uid already closed due to reconnect */
+       if (ses->need_reconnect)
+               goto smb2_session_already_dead;
+
        rc = small_smb2_init(SMB2_LOGOFF, NULL, (void **) &req);
        if (rc)
                return rc;
@@ -701,6 +705,8 @@ SMB2_logoff(const unsigned int xid, struct cifs_ses *ses)
         * No tcon so can't do
         * cifs_stats_inc(&tcon->stats.smb2_stats.smb2_com_fail[SMB2...]);
         */
+
+smb2_session_already_dead:
        return rc;
 }
 

diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
index 6fdcb1b4a106747779ae77ed365116256e79edec..800b938e4061768f5f55ee414b45afa56e6d6aa2 100644 (file)
--- a/fs/cifs/transport.c
+++ b/fs/cifs/transport.c
@@ -410,8 +410,13 @@ static int
 wait_for_free_request(struct TCP_Server_Info *server, const int timeout,
                      const int optype)
 {
-       return wait_for_free_credits(server, timeout,
-                               server->ops->get_credits_field(server, optype));
+       int *val;
+
+       val = server->ops->get_credits_field(server, optype);
+       /* Since an echo is already inflight, no need to wait to send another */
+       if (*val <= 0 && optype == CIFS_ECHO_OP)
+               return -EAGAIN;
+       return wait_for_free_credits(server, timeout, val);
 }
 
 static int allocate_mid(struct cifs_ses *ses, struct smb_hdr *in_buf,