From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ronnie Sahlberg Subject: [PATCH v4 3/3] refs.c: change ref_transaction_commit to run the commit loops once all work is finished Date: Mon, 14 Apr 2014 11:29:23 -0700 Message-ID: <1397500163-7617-4-git-send-email-sahlberg@google.com> References: <1397500163-7617-1-git-send-email-sahlberg@google.com> Cc: Ronnie Sahlberg To: git@vger.kernel.org X-From: git-owner@vger.kernel.org Mon Apr 14 20:36:52 2014 Return-path: Envelope-to: gcvg-git-2@plane.gmane.org Received: from vger.kernel.org ([209.132.180.67]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1WZlkQ-0007oh-Uk for gcvg-git-2@plane.gmane.org; Mon, 14 Apr 2014 20:36:51 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753931AbaDNSgq (ORCPT ); Mon, 14 Apr 2014 14:36:46 -0400 Received: from mail-pd0-f202.google.com ([209.85.192.202]:41767 "EHLO mail-pd0-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751053AbaDNSgp (ORCPT ); Mon, 14 Apr 2014 14:36:45 -0400 X-Greylist: delayed 425 seconds by postgrey-1.27 at vger.kernel.org; Mon, 14 Apr 2014 14:36:45 EDT Received: by mail-pd0-f202.google.com with SMTP id fp1so1086953pdb.5 for ; Mon, 14 Apr 2014 11:36:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=UsH1bnxhJO5coW8+/lRWcm/NDeqldpBBgD78Bpe1fFc=; b=HrVBxhysKcc2Mfsp6VnSzLDws6f2XmbsKSfabQBMvmF5GAjxCnx/oPaJq4Z4hzOTy7 ThNuE82Hr0a2jlNZ3LIEKNvG6Ge/Yx/EgdXNt9maYhQQKDLUtdejfeaIaCf3bhD1sLY5 qj+poRbcsV70mpzuACdOH6ywXTp1ppwknUKASsuXTfe3s8pJ40uSRZ/jjcBPS865B5dc PunwSp7lPjKspLth28nFxWB63ftAiyuiUpy/16j4LYxpcUTtgYo+gRZsfJaZGzbNxl6V cozbwjMiUcb+d26WAHiO9JKRaGefDYWY38Mg290cNTmBDsDRKq4GFJ7UwcBy6f3Dn6TP w2DQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=UsH1bnxhJO5coW8+/lRWcm/NDeqldpBBgD78Bpe1fFc=; b=iQejTW8bEE1v7OAmulm5dA9tE1rfgJl3qLhWF1jqeZueqUbOqeISCz+gxt7H8wklYL KpVG63MCSauI/7iYuFt+lxi2urI18vEmqjUGa9oOs2HyUviootszieMuc+br1WbqnQzn EHxKRt0M0zzQ0+RMLxggBaEEF7MqZpoDMBUH+FCE5oNFsTe+a9mJsjD6lp50UvfLX8Za 7PpbrTmTfyTVevRVj8nJton8fbl8059SaU5vkJee6GkeGf0DGMUObhWENkq5q9Pl5lbo qfwuk7UVkE+iEbseUvUuwN50WsH4EZaSXeJZocSElkmJ7/rf7tvCCd02qT8VP1hCpH/S UtdQ== X-Gm-Message-State: ALoCoQlcgWfYkPNnKUHRSFPokv/CQRU/9jDum9GqS3tm6GDl/d4L3M4V4g10FQzhzImocX9R1tPvRJtUsHpcpGn3evF45F8wC4gMNiTmZLOf4xHYnYTW0JnQGBLz8Cz28AE8fgYTN3vJE6uGY1rZZo1oOfN4/B98KULkXu4Q7YNCkiCvG7rDPfvqAyJ3g03YYN6ZUsaXPrOA X-Received: by 10.66.66.109 with SMTP id e13mr20704187pat.1.1397500178745; Mon, 14 Apr 2014 11:29:38 -0700 (PDT) Received: from corp2gmr1-1.hot.corp.google.com (corp2gmr1-1.hot.corp.google.com [172.24.189.92]) by gmr-mx.google.com with ESMTPS id u45si2362929yhl.4.2014.04.14.11.29.38 for (version=TLSv1.1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Mon, 14 Apr 2014 11:29:38 -0700 (PDT) Received: from sahlberg1.mtv.corp.google.com (sahlberg1.mtv.corp.google.com [172.27.69.52]) by corp2gmr1-1.hot.corp.google.com (Postfix) with ESMTP id 8DCD631C230; Mon, 14 Apr 2014 11:29:38 -0700 (PDT) Received: by sahlberg1.mtv.corp.google.com (Postfix, from userid 177442) id 50EA9E08C1; Mon, 14 Apr 2014 11:29:38 -0700 (PDT) X-Mailer: git-send-email 1.9.1.505.gd05696d In-Reply-To: <1397500163-7617-1-git-send-email-sahlberg@google.com> Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: During a transaction commit we will both update and delete refs. Since both update and delete now use the same pattern lock = lock_ref_sha1_basic() (or varient of) write_ref_sha1(lock)/delete_ref_loose(lock) unlock_ref(lock) | commit_ref_lock(lock) we can now simplify ref_transaction_commit to have one loop that locks all involved refs. A second loop that writes or flags for deletion, but does not commit, all the refs. And a final third loop that commits all the refs once all the work and preparations are complete. This makes updating/deleting multiple refs more atomic since we will not start the commit phase until all the preparations have completed successfully. Signed-off-by: Ronnie Sahlberg --- refs.c | 39 ++++++++++++++++++++++----------------- 1 file changed, 22 insertions(+), 17 deletions(-) diff --git a/refs.c b/refs.c index a14addb..87193c7 100644 --- a/refs.c +++ b/refs.c @@ -3467,42 +3467,47 @@ int ref_transaction_commit(struct ref_transaction *transaction, } } - /* Perform updates first so live commits remain referenced */ + /* Prepare all the updates/deletes */ for (i = 0; i < n; i++) { struct ref_update *update = updates[i]; - if (!is_null_sha1(update->new_sha1)) { + if (!is_null_sha1(update->new_sha1)) ret = update_ref_write(msg, update->refname, update->new_sha1, update->lock, onerr); - if (ret) - unlock_ref(update->lock); - else - commit_ref_lock(update->lock); - update->lock = NULL; - if (ret) - goto cleanup; + else { + delnames[delnum++] = update->refname; + ret = delete_ref_loose(update->lock, update->type); } + if (ret) + goto cleanup; } - /* Perform deletes now that updates are safely completed */ + ret |= repack_without_refs(delnames, delnum); + for (i = 0; i < delnum; i++) + unlink_or_warn(git_path("logs/%s", delnames[i])); + clear_loose_ref_cache(&ref_cache); + + /* Perform updates first so live commits remain referenced */ + for (i = 0; i < n; i++) { + struct ref_update *update = updates[i]; + + if (update->lock && !update->lock->delete_ref) { + ret |= commit_ref_lock(update->lock); + update->lock = NULL; + } + } + /* And finally perform all deletes */ for (i = 0; i < n; i++) { struct ref_update *update = updates[i]; if (update->lock) { - delnames[delnum++] = update->refname; - ret |= delete_ref_loose(update->lock, update->type); ret |= commit_ref_lock(update->lock); update->lock = NULL; } } - ret |= repack_without_refs(delnames, delnum); - for (i = 0; i < delnum; i++) - unlink_or_warn(git_path("logs/%s", delnames[i])); - clear_loose_ref_cache(&ref_cache); - cleanup: for (i = 0; i < n; i++) if (updates[i]->lock) -- 1.9.1.505.gd05696d