cifs: clarify comment about timestamp granularity for old servers

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>

diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index c049c7b3aa87a51d48e4d5afe6231c87bee1a910..1a135d1b85bd8c3dca017660d1c786a4d4578280 100644 (file)
--- 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) &&