From: Andreas Dilger <adilger@sun.com>
Subject: Re: [PATCH 1/2] HACK: ext3: mount fast even when recovering
Date: Tue, 14 Jul 2009 17:22:21 -0400
Message-ID: <20090714212221.GD4829@webber.adilger.int>
References: <20090714140253.25993.64525.sendpatchset@ahunter-tower>
 <20090714140301.25993.97749.sendpatchset@ahunter-tower>
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Cc: akpm@linux-foundation.org, linux-ext4@vger.kernel.org,
	Artem Bityutskiy <artem.bityutskiy@nokia.com>
To: Adrian Hunter <adrian.hunter@nokia.com>
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Sender: linux-ext4-owner@vger.kernel.org

On Jul 14, 2009  17:03 +0300, Adrian Hunter wrote:
> Speed up ext3 recovery mount time by not sync'ing the
> block device.  Instead place all dirty buffers into the
> I/O queue and add a write barrier.  This ensures that
> no subsequent write will reach the disk before all the
> recovery writes, but that we do not have to wait for the
> I/O.
> 
> +	/*
> +	 * Set an option to indicate that we want to mount fast even
> +	 * when recovering.  That is achieved by not sync'ing the
> +	 * block device, but instead placing all dirty buffers into
> +	 * the I/O queue and adding a write barrier.
> +	 */
> +	set_opt(sbi->s_mount_opt, FAST);

Is there ever a time where one wouldn't want to do a fast mount?
Surely if this speeds things up and is safe, it makes sense to do
it always.  If it isn't safe to do always, then would you EVER want
to do it if you risk corrupting your filesystem?

Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.