From: Derrick Stolee <stolee@gmail.com>
To: Junio C Hamano <gitster@pobox.com>,
Matheus Tavares Bernardino <matheus.bernardino@usp.br>
Cc: git <git@vger.kernel.org>
Subject: Re: [PATCH] entry: check for fstat() errors after checkout
Date: Tue, 21 Jul 2020 16:57:05 -0400 [thread overview]
Message-ID: <3c5a8e0d-91d7-00a4-4253-ac60f3a34d05@gmail.com> (raw)
In-Reply-To: <xmqq1rl48wpt.fsf@gitster.c.googlers.com>
On 7/21/2020 4:00 PM, Junio C Hamano wrote:
> Matheus Tavares Bernardino <matheus.bernardino@usp.br> writes:
>
>> I was looking further at this code and noticed that the conditions
>> under which we fstat() (or lstat()) an entry are slightly different
>> throughout entry.c:
>>
>> - In write_entry()'s footer, we call lstat() iff stat->refresh_cache.
>> - In write_entry()'s `write_file_entry` label, we call fstat_output()
>> when !to_tempfile.
>> - In streaming_write_entry() we call fstat_output() without checking
>> if !to_tempfile.
>> - And, finally, in fstat_output() itself, we check
>> `state->refresh_cache && !state->base_dir_len`.
>>
>> I understand we always check state->refresh_cache to avoid getting
>> stat information we won't really need later, as we are not updating
>> the index. But why do we check !to_tempfile and !state->base_dir_len?
>> Doesn't writing to a tempfile or using a checkout prefix already imply
>> !state->refresh_cache?
>
> You can easily blame the code back to e4c72923 (write_entry(): use
> fstat() instead of lstat() when file is open, 2009-02-09). Back
> then, only a single place assigned 0 to state.refresh_cache and that
> is in "checkout-index" with either base_dir_len or to_tempfile set.
>
> I do not remember, and I am fairly sure Stolee does not remember
> either. If I have to guess, this was done merely to be extra
> cautious, perhaps? As refresh_cache bit is checked first, check for
> !to_tempfile and !base_dir_len would be dead at best and redundant
> at worst.
Yeah, this portion is way outside of my expertise. I'm happy
to _try_ reading patches, but I'd have difficulty being
confident in any change in this area.
Thanks,
-Stolee
prev parent reply other threads:[~2020-07-21 20:57 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-09 2:10 [PATCH] entry: check for fstat() errors after checkout Matheus Tavares
2020-07-09 11:41 ` Derrick Stolee
2020-07-09 14:08 ` Junio C Hamano
2020-07-09 17:08 ` Junio C Hamano
2020-07-09 17:39 ` Matheus Tavares Bernardino
2020-07-09 18:09 ` Junio C Hamano
2020-07-21 15:39 ` Matheus Tavares Bernardino
2020-07-21 20:00 ` Junio C Hamano
2020-07-21 20:57 ` Derrick Stolee [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
List information: http://vger.kernel.org/majordomo-info.html
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=3c5a8e0d-91d7-00a4-4253-ac60f3a34d05@gmail.com \
--to=stolee@gmail.com \
--cc=git@vger.kernel.org \
--cc=gitster@pobox.com \
--cc=matheus.bernardino@usp.br \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this public inbox
https://80x24.org/mirrors/git.git
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).