From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Subject: Re: [PATCH -V2 4/5] ext4: Use both hi and lo bits of the group
	desc values.
Date: Fri, 21 Nov 2008 23:11:10 +0530
Message-ID: <20081121174110.GH11212@skywalker>
References: <1227285875-18011-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> <1227285875-18011-2-git-send-email-aneesh.kumar@linux.vnet.ibm.com> <1227285875-18011-3-git-send-email-aneesh.kumar@linux.vnet.ibm.com> <1227285875-18011-4-git-send-email-aneesh.kumar@linux.vnet.ibm.com> <4926F00D.6030403@redhat.com>
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Cc: cmm@us.ibm.com, tytso@mit.edu, linux-ext4@vger.kernel.org
To: Eric Sandeen <sandeen@redhat.com>, Coly Li <coyli@suse.de>
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Sender: linux-ext4-owner@vger.kernel.org

On Fri, Nov 21, 2008 at 11:29:49AM -0600, Eric Sandeen wrote:
> Aneesh Kumar K.V wrote:
> > Rename the lower bits with suffix _lo and add helper
> > to access the values. Also rename bg_itable_unused_hi
> > to bg_pad as in e2fsprogs. bg_itable_unused_hi is never
> > used before
> 
> Maybe you can add info about under which circumstances (what sort of
> fielsystem geometry) the hi bits are needed?  And the failure mode when
> we don't use them, if that's known?

Coly actually said it was added for inode reservation. But he agreed to
drop the high bits now and add them later once the performance issue
with the patch is addressed.

-aneesh