From owner-freebsd-fs@FreeBSD.ORG Mon Nov 8 15:08:12 2010 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id C0C091065672; Mon, 8 Nov 2010 15:08:12 +0000 (UTC) (envelope-from ivoras@gmail.com) Received: from mail-pv0-f182.google.com (mail-pv0-f182.google.com [74.125.83.182]) by mx1.freebsd.org (Postfix) with ESMTP id 8C3578FC0C; Mon, 8 Nov 2010 15:08:12 +0000 (UTC) Received: by pvc22 with SMTP id 22so1343640pvc.13 for ; Mon, 08 Nov 2010 07:08:12 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:mime-version:sender:received :in-reply-to:references:from:date:x-google-sender-auth:message-id :subject:to:cc:content-type:content-transfer-encoding; bh=1y/z5S8bvr0wnQxCmQAL8gHVfZt+to3OEni7ST3Gy3M=; b=uPWFt+qy1zDiShhx/XOYSk+eyqxYjBiVN15ujbFO9UPY8FRAiGDc5KC/PLm70CLh27 eQmV9/4DKyDWG+5tz1rgf6MhMUtzOJ1109dpl945vNxVebRqxd3RUbzViHGH1Cg1ayE8 r0uRbC1PqUHbxs5V4guraqlKQe4FMnF18KsZY= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:from:date :x-google-sender-auth:message-id:subject:to:cc:content-type :content-transfer-encoding; b=fUyMbRYYbIjo9CfOMVZo4F1P74ntuncrHlKkvaH3C/2hBs5Hb/9/XY3QTbyDqEdLm3 GswIJC97SrYA1lBeEUp6UP4j4GWEtRBfmkJKbsbtS7frzDZk9qF1VSf3eKB9ajBVjaNk FEQCIZvcBPaei9ZkslQ8BML33NSSaQiB6rhVA= Received: by 10.229.246.136 with SMTP id ly8mr5134771qcb.237.1289228891427; Mon, 08 Nov 2010 07:08:11 -0800 (PST) MIME-Version: 1.0 Sender: ivoras@gmail.com Received: by 10.229.40.145 with HTTP; Mon, 8 Nov 2010 07:07:29 -0800 (PST) In-Reply-To: <201011081004.59640.jhb@freebsd.org> References: <201011081004.59640.jhb@freebsd.org> From: Ivan Voras Date: Mon, 8 Nov 2010 16:07:29 +0100 X-Google-Sender-Auth: x8ab4LFurqRWZNp0ap7bTcPEfmA Message-ID: To: John Baldwin Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Cc: freebsd-fs@freebsd.org Subject: Re: The state of Giant lock in the file systems? X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 08 Nov 2010 15:08:12 -0000 On 8 November 2010 16:04, John Baldwin wrote: > On Monday, November 08, 2010 7:28:26 am Ivan Voras wrote: >> I was looking at fusefs sources and there is a dance it does with the >> Giant lock which looks fishy. >> >> Grepping for "-ir giant" in /sys/fs on 8-stable shows only a handful of >> mentionings, but if I understand it correctly only these "active" instan= ces: >> >> 1) one set of mtx_assert() calls on it in pseudofs, which I can't figure >> out what they're guarding >> 2) some manual locking and unlocking in nfsclient which appears to only >> guard printf() (???) >> 3) some more locking in nfsserver which apparently is only there to >> guard the underlying local file system >> 4) coda, which appears to be the only one marked with D_NEEDGIANT, but >> doesn't do much of its own interfacing with it >> >> Except for these, is there any more magic that would need to be resolved >> to excise Giant from VFS? >> >> Would it be correct to think that coda is the single biggest obstacle? > > Err, all the VFS_LOCK_GIANT() stuff for filesystems that do not have > MNTK_MPSAFE set. =C2=A0I believe the currently MPSAFE fs's are UFS, ZFS, = MSDOSFS, > CD9660, UDF, NFS client, and devfs. =C2=A0I think all others are !MPSAFE = still. Thanks! It seemed too easy to be true.