From owner-freebsd-fs@FreeBSD.ORG  Fri May 21 09:09:16 2004
Return-Path: <owner-freebsd-fs@FreeBSD.ORG>
Delivered-To: freebsd-fs@freebsd.org
Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125])
	by hub.freebsd.org (Postfix) with ESMTP id 414B216A4CE
	for <freebsd-fs@freebsd.org>; Fri, 21 May 2004 09:09:16 -0700 (PDT)
Received: from darkness.comp.waw.pl (darkness.comp.waw.pl [195.117.238.236])
	by mx1.FreeBSD.org (Postfix) with ESMTP id D3F0843D1D
	for <freebsd-fs@freebsd.org>; Fri, 21 May 2004 09:09:15 -0700 (PDT)
	(envelope-from pjd@darkness.comp.waw.pl)
Received: by darkness.comp.waw.pl (Postfix, from userid 1009)
	id 36EE9ACBD6; Fri, 21 May 2004 18:09:14 +0200 (CEST)
Date: Fri, 21 May 2004 18:09:14 +0200
From: Pawel Jakub Dawidek <pjd@FreeBSD.org>
To: "David E. Cross" <crossd@cs.rpi.edu>
Message-ID: <20040521160914.GE845@darkness.comp.waw.pl>
References: <1084556769.2304.20.camel@kiki.cs.rpi.edu>
Mime-Version: 1.0
Content-Type: multipart/signed; micalg=pgp-sha1;
	protocol="application/pgp-signature"; boundary="7FBusMY41sbWuT4E"
Content-Disposition: inline
In-Reply-To: <1084556769.2304.20.camel@kiki.cs.rpi.edu>
User-Agent: Mutt/1.4.2i
X-PGP-Key-URL: http://people.freebsd.org/~pjd/pjd.asc
X-OS: FreeBSD 5.2.1-RC2 i386
cc: freebsd-fs@freebsd.org
cc: moorthy@cs.rpi.edu
cc: wronkm@cs.rpi.edu
Subject: Re: Journalled UFS
X-BeenThere: freebsd-fs@freebsd.org
X-Mailman-Version: 2.1.1
Precedence: list
List-Id: Filesystems <freebsd-fs.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-fs>,
	<mailto:freebsd-fs-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-fs>
List-Post: <mailto:freebsd-fs@freebsd.org>
List-Help: <mailto:freebsd-fs-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-fs>,
	<mailto:freebsd-fs-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Fri, 21 May 2004 16:09:16 -0000


--7FBusMY41sbWuT4E
Content-Type: text/plain; charset=iso-8859-2
Content-Disposition: inline
Content-Transfer-Encoding: quoted-printable

On Fri, May 14, 2004 at 01:46:11PM -0400, David E. Cross wrote:
+> Ok... It was brought to my attention  that someone was asking for this
+> again, so I figure its time to put out an update on the status.

Great to hear!

+> Here's what I want to do:
+>=20
+> VOP/VFS entry point {
+>   Aquire Mutex with RECURSION;

mtx_lock(your_mtx);

+>   If first aquire, inc transaction ID; else don't;

if (!mtx_recursed(your_mtx))
	/* Inc transaction ID. */;

+>   NORMAL VOP/VFS Dispatch;
+>=20
+>   Release Mutex;

recursed =3D mtx_recursed(your_mtx);
mtx_unlock(your_mtx);

+>   if last release && syn_journal Checkpoint_Routine;

if (!recursed && syn_journal)
	Checkpoint_Routine;

+> }

+> Checkpoint_Routine {
+>  Aquire mutex with RECURSION:
+>  if first aquire, last_tid=3DTID;
+>  else last_tid=3DTID-1;
+>=20
+>  Dump_to last_tid;
+>=20
+>  Release mutex;
+> }
+>=20
+> I am not sure how to check if we already have a mutex, and if its
+> recursion or not vs. the mutex is already aquired but its not "ours".
+> suggestions?

I'm not sure why you want to check if mutex is already acquired.
You don't want to sleep? You can use mtx_trylock(9) or mtx_owned(9) maybe.

--=20
Pawel Jakub Dawidek                       http://www.FreeBSD.org
pjd@FreeBSD.org                           http://garage.freebsd.pl
FreeBSD committer                         Am I Evil? Yes, I Am!

--7FBusMY41sbWuT4E
Content-Type: application/pgp-signature
Content-Disposition: inline

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.2.4 (FreeBSD)

iD8DBQFArimqForvXbEpPzQRAiGwAKCuE22rNNWQmv3S43rnZhqz29D/bACeNxZq
0MfLIX0WnoZY/bO4/YaLlG4=
=CrIJ
-----END PGP SIGNATURE-----

--7FBusMY41sbWuT4E--