From: Jeff King <peff@peff.net>
To: Michael Haggerty <mhagger@alum.mit.edu>
Cc: "Junio C Hamano" <gitster@pobox.com>,
"Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>,
"Stefan Beller" <sbeller@google.com>,
"Ævar Arnfjörð Bjarmason" <avarab@gmail.com>,
"David Turner" <novalis@novalis.org>,
"Brandon Williams" <bmwill@google.com>,
git@vger.kernel.org
Subject: Re: [PATCH v2 28/29] repack_without_refs(): don't lock or unlock the packed refs
Date: Fri, 23 Jun 2017 15:56:01 -0400 [thread overview]
Message-ID: <20170623195600.cvn26gt7o5rtywy6@sigill.intra.peff.net> (raw)
In-Reply-To: <38b397dddd210f008e28d9a92218727b08a08735.1498200513.git.mhagger@alum.mit.edu>
On Fri, Jun 23, 2017 at 09:01:46AM +0200, Michael Haggerty wrote:
> Change `repack_without_refs()` to expect the packed-refs lock to be
> held already, and not to release the lock before returning. Change the
> callers to deal with lock management.
>
> This change makes it possible for callers to hold the packed-refs lock
> for a longer span of time, a possibility that will eventually make it
> possible to fix some longstanding races.
This is the sort of clue I was thinking about in my last email. :)
> The only semantic change here is that `repack_without_refs()` used to
> forgot to release the lock in the `if (!removed)` exit path. That
> omission is now fixed.
s/used to forgot/previously forgot/ or similar?
> @@ -731,14 +717,12 @@ int repack_without_refs(struct ref_store *ref_store,
> * All packed entries disappeared while we were
> * acquiring the lock.
> */
> - rollback_packed_refs(refs);
> + clear_packed_ref_cache(refs);
> return 0;
And this is the reason for the earlier "you should be able to clear the
packed ref cache without holding the lock" commit, I guess. Makes sense.
-Peff
next prev parent reply other threads:[~2017-06-23 19:56 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-23 7:01 [PATCH v2 00/29] Create a reference backend for packed refs Michael Haggerty
2017-06-23 7:01 ` [PATCH v2 01/29] t1408: add a test of stale packed refs covered by loose refs Michael Haggerty
2017-06-23 18:59 ` Jeff King
2017-06-23 20:22 ` Junio C Hamano
2017-06-23 7:01 ` [PATCH v2 02/29] add_packed_ref(): teach function to overwrite existing refs Michael Haggerty
2017-06-23 7:01 ` [PATCH v2 03/29] packed_ref_store: new struct Michael Haggerty
2017-06-23 7:01 ` [PATCH v2 04/29] packed_ref_store: move `packed_refs_path` here Michael Haggerty
2017-06-23 7:01 ` [PATCH v2 05/29] packed_ref_store: move `packed_refs_lock` member here Michael Haggerty
2017-06-23 7:01 ` [PATCH v2 06/29] clear_packed_ref_cache(): take a `packed_ref_store *` parameter Michael Haggerty
2017-06-23 7:01 ` [PATCH v2 07/29] validate_packed_ref_cache(): " Michael Haggerty
2017-06-23 7:01 ` [PATCH v2 08/29] get_packed_ref_cache(): " Michael Haggerty
2017-06-23 7:01 ` [PATCH v2 09/29] get_packed_refs(): " Michael Haggerty
2017-06-23 7:01 ` [PATCH v2 10/29] add_packed_ref(): " Michael Haggerty
2017-06-23 7:01 ` [PATCH v2 11/29] lock_packed_refs(): " Michael Haggerty
2017-06-23 7:01 ` [PATCH v2 12/29] commit_packed_refs(): " Michael Haggerty
2017-06-23 7:01 ` [PATCH v2 13/29] rollback_packed_refs(): " Michael Haggerty
2017-06-23 7:01 ` [PATCH v2 14/29] get_packed_ref(): " Michael Haggerty
2017-06-23 7:01 ` [PATCH v2 15/29] repack_without_refs(): " Michael Haggerty
2017-06-23 7:01 ` [PATCH v2 16/29] packed_peel_ref(): new function, extracted from `files_peel_ref()` Michael Haggerty
2017-06-23 7:01 ` [PATCH v2 17/29] packed_ref_store: support iteration Michael Haggerty
2017-06-23 19:12 ` Jeff King
2017-06-23 7:01 ` [PATCH v2 18/29] packed_read_raw_ref(): new function, replacing `resolve_packed_ref()` Michael Haggerty
2017-06-23 7:01 ` [PATCH v2 19/29] packed-backend: new module for handling packed references Michael Haggerty
2017-06-23 19:35 ` Jeff King
2017-06-23 19:46 ` Stefan Beller
2017-06-23 21:20 ` Junio C Hamano
2017-06-23 7:01 ` [PATCH v2 20/29] packed_ref_store: make class into a subclass of `ref_store` Michael Haggerty
2017-06-23 19:40 ` Jeff King
2017-06-23 7:01 ` [PATCH v2 21/29] commit_packed_refs(): report errors rather than dying Michael Haggerty
2017-06-23 7:01 ` [PATCH v2 22/29] commit_packed_refs(): use a staging file separate from the lockfile Michael Haggerty
2017-06-23 19:46 ` Jeff King
2017-06-24 11:43 ` Michael Haggerty
2017-06-24 11:57 ` Jeff King
2017-06-23 7:01 ` [PATCH v2 23/29] packed_refs_lock(): function renamed from lock_packed_refs() Michael Haggerty
2017-06-23 7:01 ` [PATCH v2 24/29] packed_refs_lock(): report errors via a `struct strbuf *err` Michael Haggerty
2017-06-23 7:01 ` [PATCH v2 25/29] packed_refs_unlock(), packed_refs_is_locked(): new functions Michael Haggerty
2017-06-23 7:01 ` [PATCH v2 26/29] clear_packed_ref_cache(): don't protest if the lock is held Michael Haggerty
2017-06-23 19:49 ` Jeff King
2017-06-23 7:01 ` [PATCH v2 27/29] commit_packed_refs(): remove call to `packed_refs_unlock()` Michael Haggerty
2017-06-23 19:51 ` Jeff King
2017-06-23 7:01 ` [PATCH v2 28/29] repack_without_refs(): don't lock or unlock the packed refs Michael Haggerty
2017-06-23 19:56 ` Jeff King [this message]
2017-07-01 17:11 ` Michael Haggerty
2017-06-23 7:01 ` [PATCH v2 29/29] read_packed_refs(): die if `packed-refs` contains bogus data Michael Haggerty
2017-06-23 19:58 ` Jeff King
2017-07-01 18:15 ` Michael Haggerty
2017-06-23 19:01 ` [PATCH v2 00/29] Create a reference backend for packed refs Jeff King
2017-06-23 20:00 ` Jeff King
2017-06-23 21:47 ` Junio C Hamano
2017-06-24 1:11 ` Jeff King
2017-06-24 11:14 ` Michael Haggerty
2017-06-23 20:24 ` Junio C Hamano
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