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From: Jeff King <peff@peff.net>
To: Derrick Stolee <stolee@gmail.com>
Cc: Junio C Hamano <gitster@pobox.com>, Taylor Blau <me@ttaylorr.com>,
	git@vger.kernel.org, dstolee@microsoft.com, jrnieder@gmail.com
Subject: Re: [PATCH v2 1/8] packfile: prepare for the existence of '*.rev' files
Date: Thu, 14 Jan 2021 14:57:12 -0500	[thread overview]
Message-ID: <YACiGJO+kqz2yleZ@coredump.intra.peff.net> (raw)
In-Reply-To: <10326ece-f433-4793-336e-a30786bf1f2f@gmail.com>

On Thu, Jan 14, 2021 at 07:07:08AM -0500, Derrick Stolee wrote:

> >> + * If a '.rev' file is present, it is checked for consistency, mmap'd, and
> >> + * pointers are assigned into it (instead of using the in-memory variant).
> > 
> > Hmph, I missed where it got checked for consistency, though.  If the
> > file is corrupt and has say duplicated entries, we'd happily grab
> > the data via get_be32(), for example.
> 
> Even if the consistency check is just verifying the trailing hash, that
> seems like something that requires O(N) before performing a lookup. Perhaps
> this was copied from somewhere else, or means something different?

For the .idx file, we check that the size is what we expect. This is
important because it lets us access the mapped bytes in normal use
without having to do a bounds check.

It looks like we do the same for the .rev file here, which is good.  If
calling that "checked for consistency" is too strong, I don't think it's
a big deal to drop the wording (we do not make any such claim for
open_pack_index()).

-Peff

  reply	other threads:[~2021-01-14 20:01 UTC|newest]

Thread overview: 82+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-08 18:19 [PATCH 0/8] pack-revindex: introduce on-disk '.rev' format Taylor Blau
2021-01-08 18:19 ` [PATCH 1/8] packfile: prepare for the existence of '*.rev' files Taylor Blau
2021-01-08 18:20 ` [PATCH 2/8] pack-write.c: prepare to write 'pack-*.rev' files Taylor Blau
2021-01-08 18:20 ` [PATCH 3/8] builtin/index-pack.c: write reverse indexes Taylor Blau
2021-01-08 18:20 ` [PATCH 4/8] builtin/pack-objects.c: respect 'pack.writeReverseIndex' Taylor Blau
2021-01-08 18:20 ` [PATCH 5/8] Documentation/config/pack.txt: advertise 'pack.writeReverseIndex' Taylor Blau
2021-01-08 18:20 ` [PATCH 6/8] t: prepare for GIT_TEST_WRITE_REV_INDEX Taylor Blau
2021-01-12 17:11   ` Ævar Arnfjörð Bjarmason
2021-01-12 18:40     ` Taylor Blau
2021-01-08 18:20 ` [PATCH 7/8] t: support GIT_TEST_WRITE_REV_INDEX Taylor Blau
2021-01-12 16:49   ` Derrick Stolee
2021-01-12 17:34     ` Taylor Blau
2021-01-12 17:18   ` Ævar Arnfjörð Bjarmason
2021-01-12 17:39     ` Derrick Stolee
2021-01-12 18:17       ` Taylor Blau
2021-01-08 18:20 ` [PATCH 8/8] pack-revindex: ensure that on-disk reverse indexes are given precedence Taylor Blau
2021-01-13 22:28 ` [PATCH v2 0/8] pack-revindex: introduce on-disk '.rev' format Taylor Blau
2021-01-13 22:28   ` [PATCH v2 1/8] packfile: prepare for the existence of '*.rev' files Taylor Blau
2021-01-14  7:22     ` Junio C Hamano
2021-01-14 12:07       ` Derrick Stolee
2021-01-14 19:57         ` Jeff King [this message]
2021-01-14 18:28       ` Taylor Blau
2021-01-14  7:26     ` Junio C Hamano
2021-01-14 18:13       ` Taylor Blau
2021-01-14 20:57         ` Junio C Hamano
2021-01-22 22:54     ` Jeff King
2021-01-25 17:44       ` Taylor Blau
2021-01-25 18:27         ` Jeff King
2021-01-25 19:04         ` Junio C Hamano
2021-01-25 19:23           ` Taylor Blau
2021-01-13 22:28   ` [PATCH v2 2/8] pack-write.c: prepare to write 'pack-*.rev' files Taylor Blau
2021-01-22 23:24     ` Jeff King
2021-01-25 19:15       ` Taylor Blau
2021-01-26 21:43         ` Jeff King
2021-01-13 22:28   ` [PATCH v2 3/8] builtin/index-pack.c: write reverse indexes Taylor Blau
2021-01-22 23:53     ` Jeff King
2021-01-25 20:03       ` Taylor Blau
2021-01-13 22:28   ` [PATCH v2 4/8] builtin/pack-objects.c: respect 'pack.writeReverseIndex' Taylor Blau
2021-01-22 23:57     ` Jeff King
2021-01-23  0:08       ` Jeff King
2021-01-25 20:21         ` Taylor Blau
2021-01-25 20:50           ` Jeff King
2021-01-13 22:28   ` [PATCH v2 5/8] Documentation/config/pack.txt: advertise 'pack.writeReverseIndex' Taylor Blau
2021-01-13 22:28   ` [PATCH v2 6/8] t: prepare for GIT_TEST_WRITE_REV_INDEX Taylor Blau
2021-01-13 22:28   ` [PATCH v2 7/8] t: support GIT_TEST_WRITE_REV_INDEX Taylor Blau
2021-01-13 22:28   ` [PATCH v2 8/8] pack-revindex: ensure that on-disk reverse indexes are given precedence Taylor Blau
2021-01-25 23:37 ` [PATCH v3 00/10] pack-revindex: introduce on-disk '.rev' format Taylor Blau
2021-01-25 23:37   ` [PATCH v3 01/10] packfile: prepare for the existence of '*.rev' files Taylor Blau
2021-01-29  0:27     ` Jeff King
2021-01-29  1:14       ` Taylor Blau
2021-01-30  8:39         ` Jeff King
2021-01-25 23:37   ` [PATCH v3 02/10] pack-write.c: prepare to write 'pack-*.rev' files Taylor Blau
2021-01-25 23:37   ` [PATCH v3 03/10] builtin/index-pack.c: allow stripping arbitrary extensions Taylor Blau
2021-01-29  0:28     ` Jeff King
2021-01-29  1:15       ` Taylor Blau
2021-01-25 23:37   ` [PATCH v3 04/10] builtin/index-pack.c: write reverse indexes Taylor Blau
2021-01-25 23:37   ` [PATCH v3 05/10] builtin/pack-objects.c: respect 'pack.writeReverseIndex' Taylor Blau
2021-01-25 23:37   ` [PATCH v3 06/10] Documentation/config/pack.txt: advertise 'pack.writeReverseIndex' Taylor Blau
2021-01-29  0:30     ` Jeff King
2021-01-29  1:17       ` Taylor Blau
2021-01-30  8:41         ` Jeff King
2021-01-25 23:37   ` [PATCH v3 07/10] t: prepare for GIT_TEST_WRITE_REV_INDEX Taylor Blau
2021-01-29  0:45     ` Jeff King
2021-01-29  1:09       ` Eric Sunshine
2021-01-29  1:21       ` Taylor Blau
2021-01-30  8:43         ` Jeff King
2021-01-29  2:42       ` Junio C Hamano
2021-01-25 23:37   ` [PATCH v3 08/10] t: support GIT_TEST_WRITE_REV_INDEX Taylor Blau
2021-01-29  0:47     ` Jeff King
2021-01-25 23:37   ` [PATCH v3 09/10] pack-revindex: ensure that on-disk reverse indexes are given precedence Taylor Blau
2021-01-29  0:53     ` Jeff King
2021-01-29  1:25       ` Taylor Blau
2021-01-30  8:46         ` Jeff King
2021-01-25 23:37   ` [PATCH v3 10/10] t5325: check both on-disk and in-memory reverse index Taylor Blau
2021-01-29  1:04     ` Jeff King
2021-01-29  1:05     ` Jeff King
2021-01-29  1:32       ` Taylor Blau
2021-01-30  8:47         ` Jeff King
2021-01-26  2:36   ` [PATCH v3 00/10] pack-revindex: introduce on-disk '.rev' format Junio C Hamano
2021-01-26  2:49     ` Taylor Blau
2021-01-29  1:06   ` Jeff King
2021-01-29  1:34     ` Taylor Blau

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