From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F0DA9C47094 for ; Thu, 10 Jun 2021 12:58:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D771C613C9 for ; Thu, 10 Jun 2021 12:58:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230368AbhFJNAu (ORCPT ); Thu, 10 Jun 2021 09:00:50 -0400 Received: from mail-wm1-f46.google.com ([209.85.128.46]:42604 "EHLO mail-wm1-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230247AbhFJNAs (ORCPT ); Thu, 10 Jun 2021 09:00:48 -0400 Received: by mail-wm1-f46.google.com with SMTP id l7-20020a05600c1d07b02901b0e2ebd6deso6369074wms.1 for ; Thu, 10 Jun 2021 05:58:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=message-id:in-reply-to:references:from:date:subject:fcc :content-transfer-encoding:mime-version:to:cc; bh=u6yvYyGcHBFA4/2GUp92QUUDK4fk7qE5wkIjr4JBqGY=; b=VLpD4il8hxov6gllSoSHyMuyZzBqcOavK+r7YLP7WIGU7HZcIJvVawfYGLj66iPyTU mUORb5gxv4DhoOSyKD3q8dQbrulx2dIIhujakzE2UedstTj1YRgVASG2sf9ZwYprAcPX eTYtcVbp8SajF+rR31LbrlzTcsrf6BPYttyFB7uunszJwHOkOBoTCteYHzge9NmJlCYc SDRGPN87TSsnmvrek8tT2b+3LIg7A03yxCVfkhHVkM9YulZPVSDUGVrkpNxSinCM/ayQ S5tmoDdyZQOMyrAI1xblkkUtu6epmjUSJwM1m8m67Xtq0hGV8p6s3nJHo6o+Uv6JGMRS 8Pdg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:message-id:in-reply-to:references:from:date :subject:fcc:content-transfer-encoding:mime-version:to:cc; bh=u6yvYyGcHBFA4/2GUp92QUUDK4fk7qE5wkIjr4JBqGY=; b=g1DHIJUgau+0VSF84XP0hqYSlRaZQQ00eBGR2yOioChDBQvg6ZMg1OadkmHO4u/2Pn KCLwToXtkPpN3QFEhLuwBjm8nxWkD0kNkvl6XVDz2QXCtYrVR8q4CJlGCNYoYqCiBXj3 PDxBI0XYuSCII6ikNF+dhPrq/Lyw51YcY77xNsFSAIwqohyUYbraZPQ5/aZh72tViWtb r0qk7PZY8G9gvvLNZumOIVfhLWsrdDAPlpNz+/sXyRNtwNJMgW3dVX9IOjhPS7ulcjQN QdsnI10gSphq0Yl7oT0+MHojK0swijH7GZW7/jsiUpMfTwjHoG7evqN0/9/JG7ywxPq7 a+Gw== X-Gm-Message-State: AOAM530FRLl9xjpzxzE5pQX7w83PU3Dr9CtGennvvAtJ4QJjHSS7IOTq tc63jFkg+cUcI8phkCin5gFAKpZanuM= X-Google-Smtp-Source: ABdhPJyiL7lhxfnCQ2OdxkkgLc2Sz9sJ00o81k91/oEve1qUlkVekL4rRwfHo+EfFiRlc6U5G2lVpw== X-Received: by 2002:a7b:c94a:: with SMTP id i10mr4976771wml.29.1623329871504; Thu, 10 Jun 2021 05:57:51 -0700 (PDT) Received: from [127.0.0.1] ([13.74.141.28]) by smtp.gmail.com with ESMTPSA id y8sm10064180wmi.45.2021.06.10.05.57.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 10 Jun 2021 05:57:51 -0700 (PDT) Message-Id: In-Reply-To: References: From: "Han-Wen Nienhuys via GitGitGadget" Date: Thu, 10 Jun 2021 12:57:42 +0000 Subject: [PATCH v2 2/8] refs/files-backend: stop setting errno from lock_ref_oid_basic Fcc: Sent Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit MIME-Version: 1.0 To: git@vger.kernel.org Cc: Han-Wen Nienhuys , Jonathan Tan , Han-Wen Nienhuys , Han-Wen Nienhuys Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org From: Han-Wen Nienhuys refs/files-backend.c::lock_ref_oid_basic() tries to signal how it failed to its callers using errno. It is safe to stop setting errno here, because the callers of this file-scope static function are * files_copy_or_rename_ref() * files_create_symref() * files_reflog_expire() None of them looks at errno after seeing a negative return from lock_ref_oid_basic() to make any decision, and no caller of these three functions looks at errno after they signal a failure by returning a negative value. In particular, * files_copy_or_rename_ref() - here, calls are followed by error() (which performs I/O) or write_ref_to_lockfile() (which calls parse_object() which may perform I/O) * files_create_symref() - here, calls are followed by error() or create_symref_locked() (which performs I/O and does not inspect errno) * files_reflog_expire() - here, calls are followed by error() or refs_reflog_exists() (which calls a function in a vtable that is not documented to use and/or preserve errno) Signed-off-by: Han-Wen Nienhuys Reviewed-by: Jonathan Tan --- refs/files-backend.c | 9 +-------- 1 file changed, 1 insertion(+), 8 deletions(-) diff --git a/refs/files-backend.c b/refs/files-backend.c index 677b7e4cdd2d..6aa0f5c41dd3 100644 --- a/refs/files-backend.c +++ b/refs/files-backend.c @@ -910,7 +910,6 @@ static int create_reflock(const char *path, void *cb) /* * Locks a ref returning the lock on success and NULL on failure. - * On failure errno is set to something meaningful. */ static struct ref_lock *lock_ref_oid_basic(struct files_ref_store *refs, const char *refname, @@ -922,7 +921,6 @@ static struct ref_lock *lock_ref_oid_basic(struct files_ref_store *refs, { struct strbuf ref_file = STRBUF_INIT; struct ref_lock *lock; - int last_errno = 0; int mustexist = (old_oid && !is_null_oid(old_oid)); int resolve_flags = RESOLVE_REF_NO_RECURSE; int resolved; @@ -949,7 +947,6 @@ static struct ref_lock *lock_ref_oid_basic(struct files_ref_store *refs, * to remain. */ if (remove_empty_directories(&ref_file)) { - last_errno = errno; if (!refs_verify_refname_available( &refs->base, refname, extras, skip, err)) @@ -962,7 +959,7 @@ static struct ref_lock *lock_ref_oid_basic(struct files_ref_store *refs, &lock->old_oid, type); } if (!resolved) { - last_errno = errno; + int last_errno = errno; if (last_errno != ENOTDIR || !refs_verify_refname_available(&refs->base, refname, extras, skip, err)) @@ -981,20 +978,17 @@ static struct ref_lock *lock_ref_oid_basic(struct files_ref_store *refs, if (is_null_oid(&lock->old_oid) && refs_verify_refname_available(refs->packed_ref_store, refname, extras, skip, err)) { - last_errno = ENOTDIR; goto error_return; } lock->ref_name = xstrdup(refname); if (raceproof_create_file(ref_file.buf, create_reflock, &lock->lk)) { - last_errno = errno; unable_to_lock_message(ref_file.buf, errno, err); goto error_return; } if (verify_lock(&refs->base, lock, old_oid, mustexist, err)) { - last_errno = errno; goto error_return; } goto out; @@ -1005,7 +999,6 @@ static struct ref_lock *lock_ref_oid_basic(struct files_ref_store *refs, out: strbuf_release(&ref_file); - errno = last_errno; return lock; } -- gitgitgadget