From: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
To: Taylor Blau <me@ttaylorr.com>
Cc: git@vger.kernel.org, peff@peff.net
Subject: Re: [PATCH 0/2] pack-write,repack: prevent opening packs too early
Date: Tue, 07 Sep 2021 21:48:05 +0200 [thread overview]
Message-ID: <877dfskvxc.fsf@evledraar.gmail.com> (raw)
In-Reply-To: <cover.1630461918.git.me@ttaylorr.com>
On Tue, Aug 31 2021, Taylor Blau wrote:
> This pair of patches fixes a race where the .idx is moved into place
> before the .rev file, allowing the pack to be in a state where it
> appears a .rev file wasn't generated.
>
> This can cause Git to inadvertently take the slow "generate the
> reverse index on-the-fly", which does not impact correctness, but is
> unnecessarily slow when compared to reading the .rev file.
>
> The race is fixed by moving the .idx into place only after all other
> pack-related files have already been written. The first patch fixes
> the direct `pack-objects` case, and the second patch fixes `repack`
> (which also renames pack files around).
>
> Thanks in advance for your review.
>
> Taylor Blau (2):
> pack-write.c: rename `.idx` file into place last
> builtin/repack.c: move `.idx` files into place last
>
> builtin/repack.c | 2 +-
> pack-write.c | 12 ++++++------
> 2 files changed, 7 insertions(+), 7 deletions(-)
I've reviewed this to the point of coming up with my own series on top
of it, but it can be considered separately:
https://lore.kernel.org/git/cover-0.3-00000000000-20210907T193600Z-avarab@gmail.com/
The only change (if any) would be to perhaps update the commit
message(s) to note that the *.bitmap case is left, and that the promise
of "closing the race" is still subject to the vagaries of our non-use of
fsync() here, so pedantically speaking the race is still there.
But even without those suggested changes:
Reviewed-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
next prev parent reply other threads:[~2021-09-07 19:49 UTC|newest]
Thread overview: 81+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-01 2:05 [PATCH 0/2] pack-write,repack: prevent opening packs too early Taylor Blau
2021-09-01 2:06 ` [PATCH 1/2] pack-write.c: rename `.idx` file into place last Taylor Blau
2021-09-01 2:06 ` [PATCH 2/2] builtin/repack.c: move `.idx` files " Taylor Blau
2021-09-01 3:53 ` [PATCH 0/2] pack-write,repack: prevent opening packs too early Jeff King
2021-09-01 4:29 ` Taylor Blau
2021-09-01 4:59 ` Jeff King
2021-09-01 5:12 ` Taylor Blau
2021-09-01 6:08 ` Jeff King
2021-09-01 21:40 ` Taylor Blau
2021-09-07 16:07 ` Jeff King
2021-09-07 19:42 ` [PATCH 0/3] rename *.idx file into place last (also after *.bitmap) Ævar Arnfjörð Bjarmason
2021-09-07 19:42 ` [PATCH 1/3] pack-write: use more idiomatic strbuf usage for packname construction Ævar Arnfjörð Bjarmason
2021-09-07 22:21 ` Taylor Blau
2021-09-07 23:22 ` Ævar Arnfjörð Bjarmason
2021-09-07 19:42 ` [PATCH 2/3] pack-write: split up finish_tmp_packfile() function Ævar Arnfjörð Bjarmason
2021-09-07 22:28 ` Taylor Blau
2021-09-07 19:42 ` [PATCH 3/3] pack-write: rename *.idx file into place last (really!) Ævar Arnfjörð Bjarmason
2021-09-07 22:31 ` Taylor Blau
2021-09-07 22:36 ` [PATCH 0/3] rename *.idx file into place last (also after *.bitmap) Taylor Blau
2021-09-07 19:48 ` Ævar Arnfjörð Bjarmason [this message]
2021-09-08 0:38 ` [PATCH v2 0/4] " Ævar Arnfjörð Bjarmason
2021-09-08 0:38 ` [PATCH v2 1/4] pack.h: line-wrap the definition of finish_tmp_packfile() Ævar Arnfjörð Bjarmason
2021-09-08 0:38 ` [PATCH v2 2/4] pack-write: refactor renaming in finish_tmp_packfile() Ævar Arnfjörð Bjarmason
2021-09-08 4:22 ` Taylor Blau
2021-09-08 0:38 ` [PATCH v2 3/4] pack-write: split up finish_tmp_packfile() function Ævar Arnfjörð Bjarmason
2021-09-08 0:38 ` [PATCH v2 4/4] pack-write: rename *.idx file into place last (really!) Ævar Arnfjörð Bjarmason
2021-09-08 1:14 ` Ævar Arnfjörð Bjarmason
2021-09-08 9:18 ` Ævar Arnfjörð Bjarmason
2021-09-08 4:24 ` Taylor Blau
2021-09-08 22:17 ` [PATCH v2 0/3] prevent opening packs too early Taylor Blau
2021-09-08 22:17 ` [PATCH v2 1/3] pack-write.c: rename `.idx` files into place last Taylor Blau
2021-09-08 22:17 ` [PATCH v2 2/3] builtin/repack.c: move " Taylor Blau
2021-09-08 22:17 ` [PATCH v2 3/3] builtin/index-pack.c: " Taylor Blau
2021-09-08 23:52 ` [PATCH v2 0/3] prevent opening packs too early Ævar Arnfjörð Bjarmason
2021-09-09 0:50 ` Ævar Arnfjörð Bjarmason
2021-09-09 1:13 ` Taylor Blau
2021-09-09 1:33 ` Ævar Arnfjörð Bjarmason
2021-09-09 2:36 ` Ævar Arnfjörð Bjarmason
2021-09-09 2:49 ` Taylor Blau
2021-09-09 3:24 ` [PATCH 0/9] packfile: avoid .idx rename races Taylor Blau
2021-09-09 3:24 ` [PATCH 1/9] pack.h: line-wrap the definition of finish_tmp_packfile() Taylor Blau
2021-09-09 3:24 ` [PATCH 2/9] bulk-checkin.c: store checksum directly Taylor Blau
2021-09-09 7:38 ` Ævar Arnfjörð Bjarmason
2021-09-09 3:24 ` [PATCH 3/9] pack-write: refactor renaming in finish_tmp_packfile() Taylor Blau
2021-09-09 19:29 ` Junio C Hamano
2021-09-09 21:07 ` Taylor Blau
2021-09-09 23:30 ` Junio C Hamano
2021-09-09 23:31 ` Taylor Blau
2021-09-10 1:29 ` Junio C Hamano
2021-09-09 3:24 ` [PATCH 4/9] pack-write.c: rename `.idx` files after `*.rev` Taylor Blau
2021-09-09 7:46 ` Ævar Arnfjörð Bjarmason
2021-09-09 14:37 ` Taylor Blau
2021-09-09 19:32 ` Junio C Hamano
2021-09-09 3:25 ` [PATCH 5/9] builtin/repack.c: move `.idx` files into place last Taylor Blau
2021-09-09 19:38 ` Junio C Hamano
2021-09-09 21:08 ` Taylor Blau
2021-09-09 3:25 ` [PATCH 6/9] index-pack: refactor renaming in final() Taylor Blau
2021-09-09 19:45 ` Junio C Hamano
2021-09-09 21:11 ` Taylor Blau
2021-09-09 3:25 ` [PATCH 7/9] builtin/index-pack.c: move `.idx` files into place last Taylor Blau
2021-09-09 7:52 ` Ævar Arnfjörð Bjarmason
2021-09-09 19:45 ` Junio C Hamano
2021-09-09 3:25 ` [PATCH 8/9] pack-write: split up finish_tmp_packfile() function Taylor Blau
2021-09-09 3:25 ` [PATCH 9/9] pack-objects: rename .idx files into place after .bitmap files Taylor Blau
2021-09-09 7:54 ` Ævar Arnfjörð Bjarmason
2021-09-09 19:52 ` Junio C Hamano
2021-09-09 21:13 ` Taylor Blau
2021-09-09 8:06 ` [PATCH 0/9] packfile: avoid .idx rename races Ævar Arnfjörð Bjarmason
2021-09-09 14:40 ` Taylor Blau
2021-09-09 19:52 ` Junio C Hamano
2021-09-09 23:24 ` [PATCH v2 " Taylor Blau
2021-09-09 23:24 ` [PATCH v2 1/9] pack.h: line-wrap the definition of finish_tmp_packfile() Taylor Blau
2021-09-09 23:24 ` [PATCH v2 2/9] bulk-checkin.c: store checksum directly Taylor Blau
2021-09-09 23:24 ` [PATCH v2 3/9] pack-write: refactor renaming in finish_tmp_packfile() Taylor Blau
2021-09-09 23:24 ` [PATCH v2 4/9] pack-write.c: rename `.idx` files after `*.rev` Taylor Blau
2021-09-09 23:24 ` [PATCH v2 5/9] builtin/repack.c: move `.idx` files into place last Taylor Blau
2021-09-09 23:24 ` [PATCH v2 6/9] index-pack: refactor renaming in final() Taylor Blau
2021-09-09 23:24 ` [PATCH v2 7/9] builtin/index-pack.c: move `.idx` files into place last Taylor Blau
2021-09-09 23:24 ` [PATCH v2 8/9] pack-write: split up finish_tmp_packfile() function Taylor Blau
2021-09-09 23:25 ` [PATCH v2 9/9] pack-objects: rename .idx files into place after .bitmap files Taylor Blau
2021-09-10 1:35 ` [PATCH v2 0/9] packfile: avoid .idx rename races Junio C Hamano
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