From mboxrd@z Thu Jan  1 00:00:00 1970
Message-ID: <35379d4d7cdfa8ead14c7f029ab15bb7@quanstro.net>
From: erik quanstrom <quanstro@quanstro.net>
Date: Fri, 19 Dec 2008 14:31:47 -0500
To: 9fans@9fans.net
In-Reply-To: <509071940812191121q7cbd36e4yf6ac6abf04cd84c2@mail.gmail.com>
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Subject: Re: [9fans] 9pfuse and O_APPEND
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On Fri Dec 19 14:24:52 EST 2008, anothy@gmail.com wrote:
> > client by definition knows more than the server.
>
> i assume you mean "knows less"? the server knows where EOF is and
> which files to enforce append-only on. your #1 seems to only exist
> because the client doesn't have that info.

i think it's deeper than that.

if the server has instructions to stick the write at the
end of the file, the server has the ability to prevent
any other writes while executing the append.  doing
this at the client side is hard because regardless of the
client's knowledge, there can be other clients which also
believe they know things equally well and without some
sort of locking or other shenagins on the side, there's a race.

the server is almost by definition in a better position
to append than the client.

- erik