From: Junio C Hamano <gitster@pobox.com>
To: Taylor Blau <me@ttaylorr.com>
Cc: Jonathan Tan <jonathantanmy@google.com>,
git@vger.kernel.org, stolee@gmail.com
Subject: Re: [PATCH v3 1/9] t5326: demonstrate bitmap corruption after permutation
Date: Thu, 20 Jan 2022 14:41:47 -0800 [thread overview]
Message-ID: <xmqq5yqeghck.fsf@gitster.g> (raw)
In-Reply-To: <YeneJrzjp160edGG@nand.local> (Taylor Blau's message of "Thu, 20 Jan 2022 17:11:50 -0500")
Taylor Blau <me@ttaylorr.com> writes:
> Right. The problem being that it's possible to change the MIDX's
> object order without changing its checksum. Since the .rev file's
> contents encodes the pseudo-pack order, embedding it into the MIDX is
> sufficient to guarantee that the MIDX's checksum changes whenever the
> object order does.
To slightly rephrase,
The problem being that before the change to embed reverse table in
MIDX, it was possible to change the object order without changing
the checksum, but with that change alone, if a rebuilt MIDX has the
same checksum, it is guaranteed that it records the same objects in
the same order.
Hence, shuffling between rename(2) and link(2), which was the code
change that is only necessary to force updating the existing MIDX
with newly recreated one because two MIDX with the same checksum
could record objects in different orders, is no longer necessary.
Am I on the same page as you two?
next prev parent reply other threads:[~2022-01-20 22:41 UTC|newest]
Thread overview: 87+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-08 19:26 [PATCH 0/2] midx: prevent bitmap corruption when permuting pack order Taylor Blau
2021-12-08 19:26 ` [PATCH 1/2] t5326: demonstrate bitmap corruption after permutation Taylor Blau
2021-12-08 19:26 ` [PATCH 2/2] midx.c: make changing the preferred pack safe Taylor Blau
2021-12-08 19:30 ` [PATCH 0/2] midx: prevent bitmap corruption when permuting pack order Derrick Stolee
2021-12-08 19:55 ` Jeff King
2021-12-10 18:36 ` Taylor Blau
2021-12-10 22:31 ` Taylor Blau
2021-12-11 1:39 ` Taylor Blau
2021-12-13 14:00 ` Derrick Stolee
2021-12-13 14:31 ` Taylor Blau
2021-12-14 1:55 ` [PATCH v2 0/8] " Taylor Blau
2021-12-14 1:55 ` [PATCH v2 1/8] t5326: demonstrate bitmap corruption after permutation Taylor Blau
2021-12-14 1:55 ` [PATCH v2 2/8] midx.c: make changing the preferred pack safe Taylor Blau
2021-12-14 1:55 ` [PATCH v2 3/8] pack-revindex.c: instrument loading on-disk reverse index Taylor Blau
2021-12-14 1:55 ` [PATCH v2 4/8] t5326: drop unnecessary setup Taylor Blau
2021-12-14 1:55 ` [PATCH v2 5/8] t5326: extract `test_rev_exists` Taylor Blau
2021-12-20 18:33 ` Derrick Stolee
2022-01-04 15:33 ` Taylor Blau
2021-12-14 1:55 ` [PATCH v2 6/8] t5326: move tests to t/lib-bitmap.sh Taylor Blau
2021-12-14 1:55 ` [PATCH v2 7/8] t/lib-bitmap.sh: parameterize tests over reverse index source Taylor Blau
2021-12-14 1:55 ` [PATCH v2 8/8] midx: read `RIDX` chunk when present Taylor Blau
2021-12-20 18:42 ` Derrick Stolee
2022-01-04 15:21 ` Taylor Blau
2021-12-15 19:46 ` [PATCH v2 0/8] midx: prevent bitmap corruption when permuting pack order Junio C Hamano
2021-12-15 21:37 ` Taylor Blau
2021-12-15 22:17 ` Junio C Hamano
2021-12-15 22:55 ` Junio C Hamano
2021-12-20 18:51 ` Derrick Stolee
2021-12-20 19:52 ` Taylor Blau
2021-12-20 20:09 ` Derrick Stolee
2021-12-15 22:58 ` Junio C Hamano
2021-12-15 23:01 ` Taylor Blau
2022-01-04 18:15 ` [PATCH v3 0/9] " Taylor Blau
2022-01-04 18:15 ` [PATCH v3 1/9] t5326: demonstrate bitmap corruption after permutation Taylor Blau
2022-01-20 17:55 ` Jonathan Tan
2022-01-20 22:11 ` Taylor Blau
2022-01-20 22:41 ` Junio C Hamano [this message]
2022-01-20 22:46 ` Taylor Blau
2022-01-24 17:40 ` Jonathan Tan
2022-01-04 18:15 ` [PATCH v3 2/9] midx.c: make changing the preferred pack safe Taylor Blau
2022-01-14 21:35 ` Junio C Hamano
2022-01-14 21:43 ` Junio C Hamano
2022-01-15 0:59 ` Taylor Blau
2022-01-15 6:27 ` Junio C Hamano
2022-01-20 18:08 ` Jonathan Tan
2022-01-20 22:13 ` Taylor Blau
2022-01-04 18:15 ` [PATCH v3 3/9] pack-revindex.c: instrument loading on-disk reverse index Taylor Blau
2022-01-20 18:15 ` Jonathan Tan
2022-01-20 22:18 ` Taylor Blau
2022-01-24 17:53 ` Jonathan Tan
2022-01-04 18:15 ` [PATCH v3 4/9] t5326: drop unnecessary setup Taylor Blau
2022-01-04 18:15 ` [PATCH v3 5/9] t5326: extract `test_rev_exists` Taylor Blau
2022-01-04 18:15 ` [PATCH v3 6/9] t5326: move tests to t/lib-bitmap.sh Taylor Blau
2022-01-04 18:15 ` [PATCH v3 7/9] t/lib-bitmap.sh: parameterize tests over reverse index source Taylor Blau
2022-01-24 19:15 ` Jonathan Tan
2022-01-25 21:40 ` Taylor Blau
2022-01-26 21:00 ` Jonathan Tan
2022-01-04 18:16 ` [PATCH v3 8/9] midx: read `RIDX` chunk when present Taylor Blau
2022-01-24 19:27 ` Jonathan Tan
2022-01-25 21:45 ` Taylor Blau
2022-01-26 21:28 ` Jonathan Tan
2022-01-04 18:16 ` [PATCH v3 9/9] pack-bitmap.c: gracefully fallback after opening pack/MIDX Taylor Blau
2022-01-24 19:29 ` Jonathan Tan
2022-01-25 21:46 ` Taylor Blau
2022-01-25 22:40 ` [PATCH v4 0/9] midx: prevent bitmap corruption when permuting pack order Taylor Blau
2022-01-25 22:41 ` [PATCH v4 1/9] t5326: demonstrate bitmap corruption after permutation Taylor Blau
2022-01-26 15:01 ` Ævar Arnfjörð Bjarmason
2022-01-26 20:18 ` Taylor Blau
2022-01-25 22:41 ` [PATCH v4 2/9] midx.c: make changing the preferred pack safe Taylor Blau
2022-01-25 22:41 ` [PATCH v4 3/9] pack-revindex.c: instrument loading on-disk reverse index Taylor Blau
2022-01-26 15:03 ` Ævar Arnfjörð Bjarmason
2022-01-25 22:41 ` [PATCH v4 4/9] t5326: drop unnecessary setup Taylor Blau
2022-01-25 22:41 ` [PATCH v4 5/9] t5326: extract `test_rev_exists` Taylor Blau
2022-01-26 15:04 ` Ævar Arnfjörð Bjarmason
2022-01-26 20:19 ` Taylor Blau
2022-01-25 22:41 ` [PATCH v4 6/9] t5326: move tests to t/lib-bitmap.sh Taylor Blau
2022-01-25 22:41 ` [PATCH v4 7/9] t/lib-bitmap.sh: parameterize tests over reverse index source Taylor Blau
2022-01-25 22:41 ` [PATCH v4 8/9] midx: read `RIDX` chunk when present Taylor Blau
2022-01-26 15:10 ` Ævar Arnfjörð Bjarmason
2022-01-26 20:23 ` Taylor Blau
2022-01-25 22:41 ` [PATCH v4 9/9] pack-bitmap.c: gracefully fallback after opening pack/MIDX Taylor Blau
2022-01-26 15:08 ` Ævar Arnfjörð Bjarmason
2022-01-26 17:50 ` [PATCH v4 0/9] midx: prevent bitmap corruption when permuting pack order Ævar Arnfjörð Bjarmason
2022-01-26 20:24 ` Taylor Blau
2022-01-27 17:15 ` Jonathan Tan
2022-02-24 22:50 ` Taylor Blau
2022-01-27 14:13 ` Derrick Stolee
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