From mboxrd@z Thu Jan  1 00:00:00 1970
From: Dan Cross <cross@math.psu.edu>
Message-Id: <200102080102.UAA03432@augusta.math.psu.edu>
To: 9fans@cse.psu.edu
Subject: Re: [9fans] 9p2k, fsync
In-Reply-To: <20010207191447.24C56199E1@mail.cse.psu.edu>
Cc:
Date: Wed,  7 Feb 2001 20:02:44 -0500
Topicbox-Message-UUID: 5c9f49ca-eac9-11e9-9e20-41e7f4b1d025

In article <20010207191447.24C56199E1@mail.cse.psu.edu> you write:
>I think you have to believe that when the fileserver replies to your
>write that the data is written, just like you do when you say 'fsync';
>whether the data is actually on some 'stable storage' is, in both
>cases, not known.

I'm not sure that's a leap of faith that I'm always willing to make.

Also, Scott is asking about the protocol itself, not the current
implementation.  Since one of the main principles of Plan 9 is to
abstract things into filesystems served by file servers all over the
network, which may or may not do various levels of caching, it seems a
mistake to leave something like this out.

To that end, I think that some sort of ``Tsync'' message is a good
idea.

I'll admit that the semantics are murky for the existing file server.
What does ``stable storage'' mean?  The magnetic disk cache?  The
worm?  Something else entirely?

	- Dan C.