Skip site navigation (1)Skip section navigation (2)
Date:      Mon, 19 Oct 1998 07:05:13 +1000
From:      Peter Jeremy <peter.jeremy@auss2.alcatel.com.au>
To:        hackers@FreeBSD.ORG
Subject:   Re: softupdates and sync
Message-ID:  <98Oct19.070445est.40346@border.alcanet.com.au>

next in thread | raw e-mail | index | archive | help
On Sat, 17 Oct 1998 15:56:17 -0600, Warner Losh <imp@village.org> wrote:
>I guess I'm not making myself clear.  Why doesn't sync(1) flush these
>things to disk?
sync(8) just calls sync(2).  sync(2) just starts the buffer flush - it
does not wait for the flush to complete.  This has always been true
and is the origin of the `type sync 3 times before halting system'
mantra.

> Flush the dirty buffers to disk?
sync(2) requests that all dirty buffers get flushed, it just doesn't
wait for the flush to complete.

>  It shouldn't take an unmount to do that...
Unfortunately, the only way you can guarantee that all dirty buffers
have been flushed is to unmount the partition.

Note that fsync(2) does allow you to synchronously flush all the
buffers associated with an open FD.  For most purposes, this is
adequate.

I don't know whether 3.x includes a system call which synchronously
flushes the entire buffer cache.

Peter
--
Peter Jeremy (VK2PJ)                    peter.jeremy@alcatel.com.au
Alcatel Australia Limited
41 Mandible St                          Phone: +61 2 9690 5019
ALEXANDRIA  NSW  2015                   Fax:   +61 2 9690 5247

To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-hackers" in the body of the message



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?98Oct19.070445est.40346>