From mboxrd@z Thu Jan  1 00:00:00 1970
Message-ID: <80c8eabd9be7ed7c3d35f379b7f8007f@quanstro.net>
From: erik quanstrom <quanstro@quanstro.net>
Date: Thu, 18 Dec 2008 22:43:52 -0500
To: 9fans@9fans.net
In-Reply-To: <31B5545F-E1A1-4526-8450-C81E9D16379D@sun.com>
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Subject: Re: [9fans] 9pfuse and O_APPEND
Topicbox-Message-UUID: 6a26704a-ead4-11e9-9d60-3106f5b1d025

> Agreed. Now, here's a bit that I still don't quite
> understand: Plan9 does have DMAPPEND on
> a per-Qid basis. Why was it decided not to
> have it on a per-Fid basis (which would match
> POSIX semantics 100%)?
>
> The way I understand -- DMAPPEND is just a hint
> to the server to *alway* ignore the offset in
> incoming writes. It seems that ignoring offsets
> in writes for the Fids that asked for it wouldn't be
> much more difficult, would it?

DMAPPEND, for servers that implement it, is not
a hint to the server, it's a write to the end of the file,
whatever offset that might be.

since the end is computed on the file server, multiple
concurrent writers don't cause a problem. since the
fs is in a position to serialize appends to the same
file.

- erik