Date:   Tue, 2 Apr 2019 20:28:22 -0400
From:   "bfields@fieldses.org" <bfields@fieldses.org>
To:     Trond Myklebust <trondmy@hammerspace.com>
Cc:     "bradley.kuszmaul@oracle.com" <bradley.kuszmaul@oracle.com>,
        "linux-nfs@vger.kernel.org" <linux-nfs@vger.kernel.org>
Subject: Re: directory delegations
Message-ID: <20190403002822.GA7667@fieldses.org>
References: <2065755c-f888-9c62-f6e5-f143d42c51ee@oracle.com>
 <20190402161116.GA2828@fieldses.org>
 <2f1f6582-3672-1361-4392-80cb1e62e19c@oracle.com>
 <20190402194148.GA5269@fieldses.org>
 <58230e155813e866cb057e6543ab7e61f51fedf6.camel@hammerspace.com>
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On Tue, Apr 02, 2019 at 09:51:42PM +0000, Trond Myklebust wrote:
> On Tue, 2019-04-02 at 15:41 -0400, J. Bruce Fields wrote:
> > On Tue, Apr 02, 2019 at 01:26:19PM -0400, Bradley C. Kuszmaul wrote:
> > > My simple model of metadata operations is to untar something like
> > > the linux sources.
> > > 
> > > Each file incurs a LOOKUP, CREATE, SETATTR, and WRITE, each of
> > > which
> > > is fairly high latency (even the WRITE ends up being done
> > > essentially synchronously because tar closes the file after its
> > > write(2) call.)
> > 
> > An ordinary file write delegation can help with some of that.
> > 
> > > I guess directory delegations might save the cost of LOOKUP.
> > > 
> > > Is there any hope for getting write delegations?
> > > 
> > > What other steps might be possible?
> > 
> > Trond, wasn't there a draft describing your idea that a server should
> > be
> > able to grant a write delegation on create and delay the sync?  I
> > can't
> > find it right now.
> 
> 
> Do you mean this one? 
> https://tools.ietf.org/html/draft-haynes-nfsv4-delstid-00

Maybe it's too subtle for me.  What's the part that allows delaying sync
on create?

--b.