Date:   Tue, 2 Apr 2019 15:41:48 -0400
From:   "J. Bruce Fields" <bfields@fieldses.org>
To:     "Bradley C. Kuszmaul" <bradley.kuszmaul@oracle.com>
Cc:     linux-nfs@vger.kernel.org, Trond Myklebust <trondmy@gmail.com>
Subject: Re: directory delegations
Message-ID: <20190402194148.GA5269@fieldses.org>
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 <20190402161116.GA2828@fieldses.org>
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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.

--b.