From: Steve French <stfrench@microsoft.com>
Date: Tue, 8 Oct 2019 00:27:14 -0500
Subject: [PATCH] smb3: Fix regression in time handling
Git-commit: d4cfbf04b2aafcb657eb8ea0835e5cf51d371448
References: bsc#1164565
Patch-mainline: v5.4-rc3
Fixes: cb7a69e60590 ("cifs: Initialize filesystem timestamp ranges")
Only very old servers (e.g. OS/2 and DOS) did not support
DCE TIME (100 nanosecond granularity). Fix the checks used
to set minimum and maximum times.
Fixes xfstest generic/258 (on 5.4-rc1 and later)
CC: Deepa Dinamani <deepa.kernel@gmail.com>
Acked-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Acked-by: Paulo Alcantara <palcantara@suse.de>
---
fs/cifs/cifsfs.c | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -159,8 +159,19 @@ cifs_read_super(struct super_block *sb)
else
sb->s_maxbytes = MAX_NON_LFS;
- /* BB FIXME fix time_gran to be larger for LANMAN sessions */
- sb->s_time_gran = 100;
+ /* Some very old servers like DOS and OS/2 used 2 second granularity */
+ if ((tcon->ses->server->vals->protocol_id == SMB10_PROT_ID) &&
+ ((tcon->ses->capabilities &
+ tcon->ses->server->vals->cap_nt_find) == 0) &&
+ !tcon->unix_ext) {
+ sb->s_time_gran = 1000000000; /* 1 second is max allowed gran */
+ } else {
+ /*
+ * Almost every server, including all SMB2+, uses DCE TIME
+ * ie 100 nanosecond units, since 1601. See MS-DTYP and MS-FSCC
+ */
+ sb->s_time_gran = 100;
+ }
sb->s_magic = CIFS_MAGIC_NUMBER;
sb->s_op = &cifs_super_ops;