cifs: add a timestamp to track when the lease of the cached dir was taken

and clear the timestamp when we receive a lease break.

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
diff --git a/fs/cifs/smb2misc.c b/fs/cifs/smb2misc.c
index aac384f..06d555d 100644
--- a/fs/cifs/smb2misc.c
+++ b/fs/cifs/smb2misc.c
@@ -667,6 +667,7 @@ smb2_is_valid_lease_break(char *buffer)
 				    !memcmp(rsp->LeaseKey,
 					    tcon->crfid.fid->lease_key,
 					    SMB2_LEASE_KEY_SIZE)) {
+					tcon->crfid.time = 0;
 					INIT_WORK(&tcon->crfid.lease_break,
 						  smb2_cached_lease_break);
 					queue_work(cifsiod_wq,