linux-ext4 - Re: [PATCH 01/31] tune2fs: Don't convert block # to cluster # when clearing uninit

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Message-ID: <20131007130328.GA4540@thunk.org>
Date:	Mon, 7 Oct 2013 09:03:28 -0400
From:	Theodore Ts'o <tytso@....edu>
To:	"Darrick J. Wong" <darrick.wong@...cle.com>
Cc:	Lukáš Czerner <lczerner@...hat.com>,
	linux-ext4@...r.kernel.org
Subject: Re: [PATCH 01/31] tune2fs: Don't convert block # to cluster # when
 clearing uninit_bg

On Thu, Oct 03, 2013 at 12:04:44PM -0700, Darrick J. Wong wrote:
> On Thu, Oct 03, 2013 at 06:53:38PM +0200, Lukáš Czerner wrote:
> > On Mon, 30 Sep 2013, Darrick J. Wong wrote:
> > 
> > > Date: Mon, 30 Sep 2013 18:26:49 -0700
> > > From: Darrick J. Wong <darrick.wong@...cle.com>
> > > To: tytso@....edu, darrick.wong@...cle.com
> > > Cc: linux-ext4@...r.kernel.org
> > > Subject: [PATCH 01/31] tune2fs: Don't convert block # to cluster # when
> > >     clearing uninit_bg
> > > 
> > > When we're constructing the initial block bitmap as part of removing the
> > > gdt_csum (i.e. uninit_bg) feature, we mustn't convert the block numbers to
> > > cluster numbers because ext2fs_mark_block_bitmap2() does this for us.
> > 
> > I wonder if it's possible to use the old-style bitmap interface (the
> > one which does not understand 64-bit bitmaps). If so, then you also
> > need to fix ext2fs_mark_generic_bmap() (and others) so that we
> > convert blocks to clusters if needed.
> 
> It's possible to do this (bad thing) by not specifying EXT2_FLAG_64BITS when
> calling ext2fs_openfs(); see patch 26 for a quick fix.

Bigalloc requires the new-style bitmaps, so patch 26 is the right fix
for this.

						- Ted
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