From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda2.sgi.com [192.48.176.25]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id o0D8gG8s136449 for ; Wed, 13 Jan 2010 02:42:16 -0600 Received: from crca.org.au (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id 235F31611FD for ; Wed, 13 Jan 2010 00:43:11 -0800 (PST) Received: from crca.org.au (mail.crca.org.au [67.207.131.56]) by cuda.sgi.com with ESMTP id ng1RIRqb21UROEoj for ; Wed, 13 Jan 2010 00:43:11 -0800 (PST) Message-ID: <4B4D87D8.5050900@crca.org.au> Date: Wed, 13 Jan 2010 19:44:08 +1100 From: Nigel Cunningham MIME-Version: 1.0 Subject: Re: [TuxOnIce-devel] Latest updates. References: <20100113054152.GL17483@discord.disaster> <99724068.1731191263362718752.JavaMail.root@mail-au.aconex.com> <20100113065740.GN17483@discord.disaster> <20100113081140.GO17483@discord.disaster> In-Reply-To: <20100113081140.GO17483@discord.disaster> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: xfs-bounces@oss.sgi.com Errors-To: xfs-bounces@oss.sgi.com To: Dave Chinner Cc: TuxOnIce Devel List , Nathan Scott , xfs@oss.sgi.com Hi. Dave Chinner wrote: > On Wed, Jan 13, 2010 at 05:57:40PM +1100, Dave Chinner wrote: >> On Wed, Jan 13, 2010 at 05:05:18PM +1100, Nathan Scott wrote: >>> [Looks like tuxonice is a subscriber-only list...] >>> >>> ----- "Dave Chinner" wrote: >>> >>>> On Wed, Jan 13, 2010 at 02:09:14PM +1100, Nathan Scott wrote: >>>> Agreed that it is trivial to implement but there are still some >>>> definite traps - like the fact the sb change transaction may be >>>> logged >>>> immediately but the physical superblock may not get written for some >>>> time after the mount. >>> *nod* ... it will be written when unmounted though... >> suspend in the kernel doesn't unmount filesystems. I have no idea >> what tuxonice does these days, but last time I heard it left them >> mounted but frozen over the suspend/resume cycle. > > I found the code - it doesn't unmount filesystems. The git tree is > here: > > http://git.kernel.org/?p=linux/kernel/git/nigelc/tuxonice-head.git;a=summary > > It appears that it walks the list of superblocks to grab the block > device off each mounted superblock to do it's work, so I don't see > any fundamental problem with using an attribute hanging off > sb->s_root to hold the boot time... Yeah. The idea is to have very simple code that looks at a fixed number of bytes at a known offset into the partition. The value of the bytes is stored in the image header, and compared prior to starting to resume. If the data is different, we assume the filesystem has been mounted since the image was written and it's unsafe to resume. It doesn't _need_ to be a time - just something that's guaranteed to have changed if the filesystem gets mounted afresh. By the way, sorry for the slow replies so far and for slow ones in the coming 24 hours. I'm on holidays and my father-in-law's funeral is tomorrow. Nigel _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs