From: "Darrick J. Wong" <darrick.wong@oracle.com>
Subject: Re: [PATCH 09/31] libext2fs: Rewind extent pointer when totally
 deleting an extent
Date: Mon, 7 Oct 2013 11:24:33 -0700
Message-ID: <20131007182433.GA6860@birch.djwong.org>
References: <20131001012642.28415.89353.stgit@birch.djwong.org>
 <20131001012740.28415.55304.stgit@birch.djwong.org>
 <20131007133725.GF4540@thunk.org>
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Cc: linux-ext4@vger.kernel.org
To: "Theodore Ts'o" <tytso@mit.edu>
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In-Reply-To: <20131007133725.GF4540@thunk.org>
Sender: linux-ext4-owner@vger.kernel.org

On Mon, Oct 07, 2013 at 09:37:25AM -0400, Theodore Ts'o wrote:
> On Mon, Sep 30, 2013 at 06:27:40PM -0700, Darrick J. Wong wrote:
> > During a punch operation, if we decide to delete an extent out of the extent
> > tree, the subsequent extents are moved on top of the current extent (that is to
> > say, they're memmmove'd down one slot).  Therefore it is not correct to advance
> > to the next leaf because that means we miss half the extents in the range!
> > Rereading the current pointer should be fine.
> > 
> > Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> 
> Thanks, applied.
> 
> BTW, in the future, this is the sort of change where creating a
> regression test would be highly appreciated --- especially since you
> presumably had to create test cases while you were creating the patch,
> so it's much less effort to encapsulate it into a test case while
> developing the patch.

I do have one, but it's hung up (with a bunch of other tests) in that icsum.sh
script.  I'm working on turning that into make check tests, but there's nearly
70 of them.

(Alternately, fire up fuse2fs and try to truncate a fragmented extent file.)

--D
> 
> 					- Ted
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