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From: Alasdair G Kergon <agk@redhat.com>
To: "Kasatkin, Dmitry" <dmitry.kasatkin@intel.com>
Cc: Mikulas Patocka <mpatocka@redhat.com>,
	"Alasdair G. Kergon" <agk@redhat.com>,
	dm-devel@redhat.com, alan.cox@intel.com,
	linux-fsdevel@vger.kernel.org, akpm@linux-foundation.org,
	Milan Broz <mbroz@redhat.com>
Subject: Re: dm-integrity: integrity protection device-mapper target
Date: Fri, 18 Jan 2013 23:16:33 +0000	[thread overview]
Message-ID: <20130118231633.GM27585@agk-dp.fab.redhat.com> (raw)
In-Reply-To: <CALLzPKZVo3ng=Hz4cg0qrw0nDYsPjKy5AR=AJtMg+3PU=epz1w@mail.gmail.com>

On Fri, Jan 18, 2013 at 11:43:34PM +0200, Kasatkin, Dmitry wrote:
> This patch I sent out has one missing feature what I have not pushed yet.
> In the case of non-matching blocks, it just zeros blocks and returns
> no error (zero-on-mismatch).
> Writing to the block replaces the hmac.
> It works quite nicely. mkfs and fsck is able to read and write/fix the
> filesystem.
> In normal environment, if fsck crashes, it might corrupt file system
> in the same way.
> zero-on-mismatch makes block device still accessible/fixable for fsck.
 
I'm afraid I don't buy that.

We can hardly call this "integrity" if it's designed to lose some of
your data when the machine crashes - and worse - it doesn't tell you
what you lost, but just gives you blocks of zeroes instead!

I think a redesign is needed before this goes upstream.

Alasdair


  reply	other threads:[~2013-01-18 23:16 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-01-17  4:54 dm-integrity: integrity protection device-mapper target Mikulas Patocka
2013-01-18 21:43 ` Kasatkin, Dmitry
2013-01-18 23:16   ` Alasdair G Kergon [this message]
2013-01-18 23:58     ` Kasatkin, Dmitry
2013-01-21 13:51       ` Alan Cox
2013-01-21 13:51         ` Alan Cox
2013-01-21 10:37     ` Kasatkin, Dmitry
2013-01-21 10:38     ` Kasatkin, Dmitry
2013-01-23  1:29   ` Mikulas Patocka
2013-01-23  6:09     ` [dm-devel] " Will Drewry
2013-01-23 10:20       ` Kasatkin, Dmitry
2013-01-28  1:43         ` Will Drewry
2013-01-23  9:15     ` Spelic
2013-01-23 10:19     ` Kasatkin, Dmitry
2013-01-23 10:19       ` Kasatkin, Dmitry

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