From: Jeff King <peff@peff.net>
To: Junio C Hamano <gitster@pobox.com>
Cc: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>,
git@vger.kernel.org, "Han-Wen Nienhuys" <hanwen@google.com>,
"Michael Haggerty" <mhagger@alum.mit.edu>
Subject: Re: [PATCH v2 08/11] refs/files: add a comment about refs_reflog_exists() call
Date: Tue, 20 Jul 2021 03:22:03 -0400 [thread overview]
Message-ID: <YPZ5mzknK/nzKNCh@coredump.intra.peff.net> (raw)
In-Reply-To: <xmqqa6mintjx.fsf@gitster.g>
On Mon, Jul 19, 2021 at 09:43:14AM -0700, Junio C Hamano wrote:
> >> + * such thing as a lock on the reflog, instead we always lock
> >> + * the "loose ref" (even if packet) above with
> >> + * lock_ref_oid_basic().
> >> + *
> >> + * If race happens we've got nothing more to do, we were asked
> >> + * to delete the reflog, and it's not there anymore. Great!
> >> + */
> >> if (!refs_reflog_exists(ref_store, refname)) {
> >> unlock_ref(lock);
> >> return 0;
> >
> > I think everything is accurate here, though I wouldn't have made the
> > distinction with "locking the loose ref". There is no such thing as
> > locking a packed ref; we always take the loose lock.
> >
> > s/packet/packed/, and maybe s/If race/If a race/.
>
> Meaning, there is no such thing as locking a packed ref or a loose
> ref, we just lock a "ref" and the way it is done in files backend is
> by creating a lockfile as if we are creating/updating a loose one?
Yes, exactly. We do take a lock on the packed-refs file sometimes, but I
generally think "lock the ref" always means to take refs/heads/foo.lock
in the filesystem. Probably not all that important, but if we need a
re-roll to clarify language anyway...:)
> I do agree that the second sentence needs rewriting to make it less
> confusing. lock_ref_oid_basic() being the way to lock "a ref" is
> not limited to cases where we want to do something to do to the
> reflog.
>
> Taking all together, perhaps:
>
> When refs are deleted, their reflog is deleted before the
> ref itself is deleted. This is because there is no separate
> lock for reflog---instead we take a lock on the ref with
> lock_ref_oid_basic().
>
> If a race happens we've got nothing more to do...
Yeah, that reads fine to me.
-Peff
next prev parent reply other threads:[~2021-07-20 7:22 UTC|newest]
Thread overview: 88+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-14 11:17 [PATCH] refs file backend: remove dead "errno == EISDIR" code Ævar Arnfjörð Bjarmason
2021-07-14 16:21 ` Jeff King
2021-07-14 19:07 ` Ævar Arnfjörð Bjarmason
2021-07-14 23:15 ` Jeff King
2021-07-15 0:02 ` Ævar Arnfjörð Bjarmason
2021-07-15 5:16 ` Jeff King
2021-07-17 1:28 ` Junio C Hamano
2021-07-17 2:33 ` Jeff King
2021-07-19 15:42 ` Junio C Hamano
2021-07-19 16:59 ` Junio C Hamano
2021-07-17 21:36 ` Ævar Arnfjörð Bjarmason
2021-07-16 14:12 ` [PATCH v2 00/11] fix "git reflog expire" race & get rid of EISDIR in refs API Ævar Arnfjörð Bjarmason
2021-07-16 14:12 ` [PATCH v2 01/11] refs/packet: add missing BUG() invocations to reflog callbacks Ævar Arnfjörð Bjarmason
2021-07-16 14:12 ` [PATCH v2 02/11] refs/files: remove unused REF_DELETING in lock_ref_oid_basic() Ævar Arnfjörð Bjarmason
2021-07-17 2:03 ` Jeff King
2021-07-19 16:16 ` Junio C Hamano
2021-07-20 7:19 ` Jeff King
2021-07-16 14:12 ` [PATCH v2 03/11] refs/files: remove unused "extras/skip" " Ævar Arnfjörð Bjarmason
2021-07-16 14:13 ` [PATCH v2 04/11] refs/files: remove unused "skip" in lock_raw_ref() too Ævar Arnfjörð Bjarmason
2021-07-16 14:13 ` [PATCH v2 05/11] refs/debug: re-indent argument list for "prepare" Ævar Arnfjörð Bjarmason
2021-07-16 14:13 ` [PATCH v2 06/11] refs API: pass the "lock OID" to reflog "prepare" Ævar Arnfjörð Bjarmason
2021-07-17 2:04 ` Jeff King
2021-07-19 16:30 ` Junio C Hamano
2021-07-19 19:21 ` Ævar Arnfjörð Bjarmason
2021-07-16 14:13 ` [PATCH v2 07/11] refs: make repo_dwim_log() accept a NULL oid Ævar Arnfjörð Bjarmason
2021-07-16 14:13 ` [PATCH v2 08/11] refs/files: add a comment about refs_reflog_exists() call Ævar Arnfjörð Bjarmason
2021-07-17 2:08 ` Jeff King
2021-07-19 16:43 ` Junio C Hamano
2021-07-20 7:22 ` Jeff King [this message]
2021-07-16 14:13 ` [PATCH v2 09/11] reflog expire: don't lock reflogs using previously seen OID Ævar Arnfjörð Bjarmason
2021-07-17 2:23 ` Jeff King
2021-08-17 13:35 ` Han-Wen Nienhuys
2021-08-18 21:05 ` Junio C Hamano
2021-08-19 10:06 ` Carlo Marcelo Arenas Belón
2021-08-20 2:30 ` Junio C Hamano
2021-07-16 14:13 ` [PATCH v2 10/11] refs/files: remove unused "oid" in lock_ref_oid_basic() Ævar Arnfjörð Bjarmason
2021-07-17 2:26 ` Jeff King
2021-07-16 14:13 ` [PATCH v2 11/11] refs/files: remove unused "errno == EISDIR" code Ævar Arnfjörð Bjarmason
2021-07-17 2:30 ` Jeff King
2021-07-17 2:34 ` [PATCH v2 00/11] fix "git reflog expire" race & get rid of EISDIR in refs API Jeff King
2021-07-20 10:24 ` [PATCH v3 00/12] " Ævar Arnfjörð Bjarmason
2021-07-20 10:24 ` [PATCH v3 01/12] refs/packet: add missing BUG() invocations to reflog callbacks Ævar Arnfjörð Bjarmason
2021-07-20 10:24 ` [PATCH v3 02/12] refs/files: remove unused REF_DELETING in lock_ref_oid_basic() Ævar Arnfjörð Bjarmason
2021-08-02 17:17 ` Junio C Hamano
2021-07-20 10:24 ` [PATCH v3 03/12] refs/files: remove unused "extras/skip" " Ævar Arnfjörð Bjarmason
2021-07-20 10:24 ` [PATCH v3 04/12] refs/files: remove unused "skip" in lock_raw_ref() too Ævar Arnfjörð Bjarmason
2021-07-20 10:24 ` [PATCH v3 05/12] refs/debug: re-indent argument list for "prepare" Ævar Arnfjörð Bjarmason
2021-07-20 10:24 ` [PATCH v3 06/12] refs API: pass the "lock OID" to reflog "prepare" Ævar Arnfjörð Bjarmason
2021-07-21 17:40 ` Junio C Hamano
2021-07-21 17:47 ` Junio C Hamano
[not found] ` <CAFQ2z_PuNJ_KtS_O9R2s0jdGbNNKnKdS3=_-nEu6367pteCxwA@mail.gmail.com>
2021-07-23 19:41 ` Ævar Arnfjörð Bjarmason
2021-07-23 20:49 ` Junio C Hamano
2021-07-26 5:39 ` Ævar Arnfjörð Bjarmason
2021-07-26 17:47 ` Junio C Hamano
2021-07-20 10:24 ` [PATCH v3 07/12] refs: make repo_dwim_log() accept a NULL oid Ævar Arnfjörð Bjarmason
2021-07-20 10:24 ` [PATCH v3 08/12] refs/files: add a comment about refs_reflog_exists() call Ævar Arnfjörð Bjarmason
2021-07-20 10:24 ` [PATCH v3 09/12] reflog expire: don't lock reflogs using previously seen OID Ævar Arnfjörð Bjarmason
2021-07-20 10:24 ` [PATCH v3 10/12] refs/files: remove unused "oid" in lock_ref_oid_basic() Ævar Arnfjörð Bjarmason
2021-07-20 10:24 ` [PATCH v3 11/12] refs/files: remove unused "errno == EISDIR" code Ævar Arnfjörð Bjarmason
2021-07-20 10:24 ` [PATCH v3 12/12] refs/files: remove unused "errno != ENOTDIR" condition Ævar Arnfjörð Bjarmason
2021-07-26 23:44 ` [PATCH v4 00/11] fix "git reflog expire" race & get rid of EISDIR in refs API Ævar Arnfjörð Bjarmason
2021-07-26 23:44 ` [PATCH v4 01/11] refs/packet: add missing BUG() invocations to reflog callbacks Ævar Arnfjörð Bjarmason
2021-07-26 23:44 ` [PATCH v4 02/11] refs/files: remove unused REF_DELETING in lock_ref_oid_basic() Ævar Arnfjörð Bjarmason
2021-07-26 23:44 ` [PATCH v4 03/11] refs/files: remove unused "extras/skip" " Ævar Arnfjörð Bjarmason
2021-07-26 23:44 ` [PATCH v4 04/11] refs/files: remove unused "skip" in lock_raw_ref() too Ævar Arnfjörð Bjarmason
2021-07-26 23:44 ` [PATCH v4 05/11] refs/debug: re-indent argument list for "prepare" Ævar Arnfjörð Bjarmason
2021-07-26 23:44 ` [PATCH v4 06/11] refs: make repo_dwim_log() accept a NULL oid Ævar Arnfjörð Bjarmason
2021-07-26 23:44 ` [PATCH v4 07/11] refs/files: add a comment about refs_reflog_exists() call Ævar Arnfjörð Bjarmason
2021-07-26 23:44 ` [PATCH v4 08/11] reflog expire: don't lock reflogs using previously seen OID Ævar Arnfjörð Bjarmason
2021-08-02 17:26 ` Junio C Hamano
2021-08-04 9:56 ` Ævar Arnfjörð Bjarmason
2021-07-26 23:44 ` [PATCH v4 09/11] refs/files: remove unused "oid" in lock_ref_oid_basic() Ævar Arnfjörð Bjarmason
2021-07-26 23:44 ` [PATCH v4 10/11] refs/files: remove unused "errno == EISDIR" code Ævar Arnfjörð Bjarmason
2021-07-26 23:44 ` [PATCH v4 11/11] refs/files: remove unused "errno != ENOTDIR" condition Ævar Arnfjörð Bjarmason
2021-08-23 11:36 ` [PATCH v5 00/13] fix "git reflog expire" race & get rid of EISDIR in refs API Ævar Arnfjörð Bjarmason
2021-08-23 11:36 ` [PATCH v5 01/13] refs/packet: add missing BUG() invocations to reflog callbacks Ævar Arnfjörð Bjarmason
2021-08-23 11:36 ` [PATCH v5 02/13] refs/files: remove unused REF_DELETING in lock_ref_oid_basic() Ævar Arnfjörð Bjarmason
2021-08-23 11:36 ` [PATCH v5 03/13] refs: drop unused "flags" parameter to lock_ref_oid_basic() Ævar Arnfjörð Bjarmason
2021-08-23 11:36 ` [PATCH v5 04/13] refs/files: remove unused "extras/skip" in lock_ref_oid_basic() Ævar Arnfjörð Bjarmason
2021-08-23 11:36 ` [PATCH v5 05/13] refs/files: remove unused "skip" in lock_raw_ref() too Ævar Arnfjörð Bjarmason
2021-08-23 11:36 ` [PATCH v5 06/13] refs/debug: re-indent argument list for "prepare" Ævar Arnfjörð Bjarmason
2021-08-23 11:36 ` [PATCH v5 07/13] refs: make repo_dwim_log() accept a NULL oid Ævar Arnfjörð Bjarmason
2021-08-23 11:36 ` [PATCH v5 08/13] refs/files: add a comment about refs_reflog_exists() call Ævar Arnfjörð Bjarmason
2021-08-23 11:36 ` [PATCH v5 09/13] reflog expire: don't lock reflogs using previously seen OID Ævar Arnfjörð Bjarmason
2021-08-23 11:36 ` [PATCH v5 10/13] refs API: remove OID argument to reflog_expire() Ævar Arnfjörð Bjarmason
2021-08-23 11:36 ` [PATCH v5 11/13] refs/files: remove unused "oid" in lock_ref_oid_basic() Ævar Arnfjörð Bjarmason
2021-08-23 11:36 ` [PATCH v5 12/13] refs/files: remove unused "errno == EISDIR" code Ævar Arnfjörð Bjarmason
2021-08-23 11:36 ` [PATCH v5 13/13] refs/files: remove unused "errno != ENOTDIR" condition Ævar Arnfjörð Bjarmason
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