Question regarding CIFS cache=loose behavior.

[Tetsuo Handa]

Jeffrey Layton wrote:
> > ...or that samba is omitting it and is sending cached info instead of
> > doing the lstat() call? I'm not sure if it does that, but I don't
> > think you should draw too many conclusions about the behavior of
> > cifs.ko from stracing smbd.
> > 
> > What may make more sense is to get network captures and analyze the
> > behavior from that perspective.
> > 
> 
> ...or maybe it *is* cifs.ko. From cifs_inode_needs_reval:
> 
> 
>         if (!time_in_range(jiffies, cifs_i->time,
>                                 cifs_i->time + cifs_sb->actimeo))
>                 return true;
> 
> 
> ...I think though that if cifs_i->time == jiffies and actimeo=0, then
> that condition will be false. As a quick check, it might be good to add
> something like this before that if statement and then rerun your test:
> 
> 	if (!cifs_sb->actimeo)
> 		return true;
> 
> That should get rid of that particular corner case.

Yes, I confirmed that below change fixes this problem. Thank you.

--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -1737,6 +1737,8 @@ cifs_inode_needs_reval(struct inode *inode)
 	if (cifs_i->time == 0)
 		return true;
 
+	if (!cifs_sb->actimeo)
+		return true;
 	if (!time_in_range(jiffies, cifs_i->time,
 				cifs_i->time + cifs_sb->actimeo))
 		return true;