From: Mike Snitzer <snitzer@redhat.com>
To: Milan Broz <mbroz@redhat.com>
Cc: Sami Tolvanen <samitolvanen@google.com>,
Mikulas Patocka <mpatocka@redhat.com>,
Mandeep Baines <msb@chromium.org>, Will Drewry <wad@chromium.org>,
Alasdair Kergon <agk@redhat.com>,
dm-devel@redhat.com, linux-kernel@vger.kernel.org,
Kees Cook <keescook@chromium.org>,
Mark Salyzyn <salyzyn@google.com>
Subject: Re: [PATCH v2 0/2] dm verity: add support for error correction
Date: Mon, 7 Dec 2015 14:07:43 -0500 [thread overview]
Message-ID: <20151207190743.GA30593@redhat.com> (raw)
In-Reply-To: <5665CAD5.9000704@redhat.com>
On Mon, Dec 07 2015 at 1:07pm -0500,
Milan Broz <mbroz@redhat.com> wrote:
> On 12/07/2015 05:31 PM, Sami Tolvanen wrote:
> > On Mon, Dec 07, 2015 at 09:58:14AM -0500, Mike Snitzer wrote:
> >> Great. Moving forward it'd be awesome if you could work to get your
> >> verity FEC support regression tests into cryptsetup's tests.
> >
> > Sure. These tests would basically involve generating a valid disk
> > image, corrupting it up to the theoretical maximum, and verifying that
> > dm-verity can correct it.
>
> Does the code handle/report even the same type of data corruption
> for RS blocks? Or this is just silently ignored until
> data area corruption happens?
> Sorry, I did not study the code here, I am just curious :)
>
> (IOW I mean if data are ok but recovery metadata is corrupted.)
There is no preemptive accessing/checking of the RS blocks. Once a
parity is needed for a given block, due to some corruption, the RS block
will be accessed with:
fec_decode_bufs -> fec_read_parity() -> fec_decode_rs8() -> decode_rs8()
I'm not seeing any verification of the metadata in fec_read_parity() --
so it would seem that corrupt RS blocks would result in -EBADMSG being
returned from decode_rs8() (by virtue of incorrect parity being passed
to decode_rs8).
Sami (or others) am I right?
next prev parent reply other threads:[~2015-12-07 19:07 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-05 2:02 [PATCH 0/4] dm verity: add support for error correction Sami Tolvanen
2015-11-05 2:02 ` [PATCH 1/4] dm verity: clean up duplicate hashing code Sami Tolvanen
2015-11-17 22:32 ` Kees Cook
2015-11-05 2:02 ` [PATCH 2/4] dm verity: separate function for parsing opt args Sami Tolvanen
2015-11-17 22:33 ` Kees Cook
2015-12-02 20:16 ` Mike Snitzer
2015-11-05 2:02 ` [PATCH 3/4] dm verity: add support for forward error correction Sami Tolvanen
2015-11-05 5:36 ` kbuild test robot
2015-11-05 22:06 ` kbuild test robot
2015-11-05 2:02 ` [PATCH 4/4] dm verity: ignore zero blocks Sami Tolvanen
2015-11-05 22:13 ` kbuild test robot
2015-11-05 7:34 ` [PATCH 0/4] dm verity: add support for error correction Milan Broz
2015-11-05 17:33 ` Sami Tolvanen
2015-11-09 16:37 ` Mike Snitzer
2015-11-09 19:19 ` Sami Tolvanen
2015-11-09 19:58 ` Mike Snitzer
2015-11-12 10:30 ` Milan Broz
2015-12-03 9:36 ` Sami Tolvanen
2015-11-12 18:50 ` Mikulas Patocka
2015-12-03 9:33 ` Sami Tolvanen
2015-12-02 20:22 ` Mike Snitzer
2015-12-03 9:11 ` Sami Tolvanen
2015-11-06 17:23 ` Mikulas Patocka
2015-11-06 19:06 ` Sami Tolvanen
2015-11-06 19:20 ` [dm-devel] " Zdenek Kabelac
2015-11-06 20:27 ` Sami Tolvanen
2015-11-06 21:05 ` Zdenek Kabelac
2015-11-06 21:23 ` Sami Tolvanen
2015-11-07 15:29 ` Mikulas Patocka
2015-11-07 15:20 ` Mikulas Patocka
2015-11-07 15:18 ` Mikulas Patocka
2015-11-09 15:06 ` Austin S Hemmelgarn
2015-12-03 14:26 ` [PATCH v2 0/2] " Sami Tolvanen
2015-12-03 14:26 ` [PATCH v2 1/2] dm verity: add support for forward " Sami Tolvanen
2015-12-03 14:26 ` [PATCH v2 2/2] dm verity: ignore zero blocks Sami Tolvanen
2015-12-03 19:54 ` [PATCH v2 0/2] dm verity: add support for error correction Mike Snitzer
2015-12-03 23:05 ` Mike Snitzer
2015-12-04 10:03 ` Sami Tolvanen
2015-12-04 21:09 ` Mike Snitzer
2015-12-07 13:21 ` Sami Tolvanen
2015-12-07 14:58 ` Mike Snitzer
2015-12-07 16:31 ` Sami Tolvanen
2015-12-07 18:07 ` Milan Broz
2015-12-07 19:07 ` Mike Snitzer [this message]
2015-12-08 10:18 ` Sami Tolvanen
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