SMB3: parsing for new snapshot timestamp mount parm

New mount option "snapshot=<time>" to allow mounting an earlier
version of the remote volume (if such a snapshot exists on
the server).

Note that eventually specifying a snapshot time of 1 will allow
the user to mount the oldest snapshot. A subsequent patch
add the processing for that and another for actually specifying
the "time warp" create context on SMB2/SMB3 open.

Check to make sure SMB2 negotiated, and ensure that
we use a different tcon if mount same share twice
but with different snaphshot times

Signed-off-by: Steve French <smfrench@gmail.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 1f17f6bd7a60..3e95191fcb95 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -525,6 +525,7 @@ struct smb_vol {
 	struct sockaddr_storage srcaddr; /* allow binding to a local IP */
 	struct nls_table *local_nls;
 	unsigned int echo_interval; /* echo interval in secs */
+	__u64 snapshot_time; /* needed for timewarp tokens */
 	unsigned int max_credits; /* smb3 max_credits 10 < credits < 60000 */
 };
 
@@ -932,6 +933,7 @@ struct cifs_tcon {
 	__u32 maximal_access;
 	__u32 vol_serial_number;
 	__le64 vol_create_time;
+	__u64 snapshot_time; /* for timewarp tokens - timestamp of snapshot */
 	__u32 ss_flags;		/* sector size flags */
 	__u32 perf_sector_size; /* best sector size for perf */
 	__u32 max_chunks;