From: Steve French <stfrench@microsoft.com>
Date: Fri, 11 Oct 2019 17:36:13 -0700
Subject: [PATCH] cifs: clarify comment about timestamp granularity for old
 servers
Git-commit: 553292a6342bc9e5636953ac6e20bccedaacbd1c
Patch-mainline: v5.4-rc5
References: bsc#1192606

It could be confusing why we set granularity to 1 seconds rather
than 2 seconds (1 second is the max the VFS allows) for these
mounts to very old servers ...

Signed-off-by: Steve French <stfrench@microsoft.com>
Acked-by: Enzo Matsumiya <ematsumiya@suse.de>
---
 fs/cifs/cifsfs.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index c049c7b3aa87..1a135d1b85bd 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -169,7 +169,13 @@ cifs_read_super(struct super_block *sb)
 	else
 		sb->s_maxbytes = MAX_NON_LFS;
 
-	/* Some very old servers like DOS and OS/2 used 2 second granularity */
+	/*
+	 * Some very old servers like DOS and OS/2 used 2 second granularity
+	 * (while all current servers use 100ns granularity - see MS-DTYP)
+	 * but 1 second is the maximum allowed granularity for the VFS
+	 * so for old servers set time granularity to 1 second while for
+	 * everything else (current servers) set it to 100ns.
+	 */
 	if ((tcon->ses->server->vals->protocol_id == SMB10_PROT_ID) &&
 	    ((tcon->ses->capabilities &
 	      tcon->ses->server->vals->cap_nt_find) == 0) &&
-- 
2.33.1