Re: atimes not updated over NFS

[Jens Axboe <jens.axboe@oracle.com>]

On Mon, Jan 28 2008, J. Bruce Fields wrote:
> On Mon, Jan 28, 2008 at 09:59:40PM -0500, bfields wrote:
> > On Tue, Jan 22, 2008 at 12:17:17PM -0500, bfields wrote:
> > > On Mon, Jan 21, 2008 at 04:09:25PM -0500, bfields wrote:
> > > > On Mon, Jan 21, 2008 at 10:02:30PM +0100, Frank van Maarseveen wrote:
> > > > > 2.6.22.10:
> > > > > 	t
> > > > > 	t + 2
> > > > > 	t + 2
> > > > > 
> > > > > (same behavior)
> > > > > 
> > > > > 2.6.23.12:
> > > > > 	t
> > > > > 	t
> > > > > 	t
> > > > > 
> > > > > definately not good. "cat" on the server updates atime again.
> > > > 
> > > > Yes, that looks like a server bug, and this:...
> > > > 
> > > > > 
> > > > > 
> > > > > Trying a different combination of kernels:
> > > > > 
> > > > > server 2.6.23.12, client 2.6.22.10:
> > > > > 	t
> > > > > 	t
> > > > > 	t
> > > > > 
> > > > > server 2.6.22.10, client 2.6.23.12:
> > > > > 	t
> > > > > 	t + 2
> > > > > 	t + 2
> > > > 
> > > > ...confirms that since the results appear to depend only on the server
> > > > version, not on the client version.
> > > 
> > > And I can confirm this here on 2.6.24-rc8 (+ a few patches).
> > > Unfortunately, I don't have any suggestion better right now than
> > > bisecting....
> > 
> > It looks like this happened in the switch from sendfile to sparse.
> 							     ^^^^^^
> 							err, splice
> 
> > Jens, any advice?  What happened was nfsd reads stopped updating the
> > atime after the following commit.
> 
> Erm, sorry, wrong commit--it's the following one that touches nfsd,
> below.

Probably because do_generic_mapping_read() does a file_accessed() on the
input file. Does this fixup current -git?

diff --git a/fs/splice.c b/fs/splice.c
index 56b802b..c212fde 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -1090,8 +1090,10 @@ long do_splice_direct(struct file *in, loff_t *ppos, struct file *out,
 	long ret;
 
 	ret = splice_direct_to_actor(in, &sd, direct_splice_actor);
-	if (ret > 0)
+	if (ret > 0) {
 		*ppos += ret;
+		file_accessed(in);
+	}
 
 	return ret;
 }

-- 
Jens Axboe