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Date:   Wed, 21 Apr 2021 07:55:41 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     "Darrick J. Wong" <djwong@kernel.org>
Cc:     Christoph Hellwig <hch@lst.de>, linux-xfs@vger.kernel.org,
        "Gustavo A . R . Silva" <gustavoars@kernel.org>
Subject: Re: [PATCH 2/7] xfs: clean up the EFI and EFD log format handling
Message-ID: <20210421055541.GA28961@lst.de>
References: <20210419082804.2076124-1-hch@lst.de> <20210419082804.2076124-3-hch@lst.de> <20210420170529.GH3122264@magnolia>
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On Tue, Apr 20, 2021 at 10:05:29AM -0700, Darrick J. Wong wrote:
> Hmm... so the behavior change here is that 32-bit kernels will start
> logging 16-byte xfs_extent structures (like 64-bit kernels)?

Yes.

> I see that
> xfs_extent_32 was added for 2.6.18; won't this break recovery on
> everything from before that?

Where everything is a 32-bit kernel that doesn't align properly, yes.

> Granted, 2.6.17 came out 15 years ago and the last 2.6.16 LTS kernel was
> released in 2008 so maybe we don't care, but this would seem to be a
> breaking change, right?  This seems like a reasonable change for all V5
> filesystems (since that format emerged well after 2.6.18), but not so
> good for V4.

Err, why?