From: "hch@infradead.org" <hch@infradead.org>
To: Trond Myklebust <trondmy@hammerspace.com>
Cc: "hch@infradead.org" <hch@infradead.org>,
"tao.lyu@epfl.ch" <tao.lyu@epfl.ch>,
"linux-nfs@vger.kernel.org" <linux-nfs@vger.kernel.org>
Subject: Re: Question about O_APPEND | O_DIRECT
Date: Mon, 27 Nov 2023 09:19:35 -0800 [thread overview]
Message-ID: <ZWTPp8R6ywfT9hRS@infradead.org> (raw)
In-Reply-To: <20107e878f185628a8d498ebb046e55618abfd4f.camel@hammerspace.com>
On Mon, Nov 27, 2023 at 05:08:22PM +0000, Trond Myklebust wrote:
> Note that APPEND would only really work with O_DIRECT, since it is
> anathema to cached I/O to not be able to control the placement of the
> data.
Yes.
> In addition, the model will always break down if someone decides they
> want to write a log entry of size > wsize. Once you have to split up
> the data, you (obviously) lose the atomicity you need in order to write
> a contiguous record.
Yes. Note that there is work going on to define atomic I/O limits
on the various Linux lists currently. Although in the block layer
we also have a separate limit for the maximum append size already.
next prev parent reply other threads:[~2023-11-27 17:19 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-23 18:14 Question about O_APPEND | O_DIRECT Tao Lyu
2023-11-25 23:54 ` Trond Myklebust
2023-11-27 15:28 ` Tao Lyu
2023-11-27 16:36 ` Christoph Hellwig
2023-11-27 16:41 ` Tao Lyu
2023-11-27 16:50 ` Chuck Lever III
2023-11-27 16:55 ` Christoph Hellwig
2023-11-27 16:59 ` Chuck Lever III
2023-11-28 13:06 ` Christoph Hellwig
2023-11-28 1:50 ` Rick Macklem
2023-11-28 13:09 ` Christoph Hellwig
2023-11-28 18:28 ` Trond Myklebust
2023-11-27 17:08 ` Trond Myklebust
2023-11-27 17:19 ` hch [this message]
2023-11-27 17:23 ` Tao Lyu
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