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=-2.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 616AAC28CBC for ; Sat, 9 May 2020 08:00:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2DCB22184D for ; Sat, 9 May 2020 08:00:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=web.de header.i=@web.de header.b="B/IQVjRm" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727798AbgEIIAa (ORCPT ); Sat, 9 May 2020 04:00:30 -0400 Received: from mout.web.de ([212.227.17.11]:47711 "EHLO mout.web.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725850AbgEIIA1 (ORCPT ); Sat, 9 May 2020 04:00:27 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=web.de; s=dbaedf251592; t=1589011215; bh=zrxLDBTMmEIP/qqOFO2evz9mc4UXaGDRoyYKqIZKBmU=; h=X-UI-Sender-Class:Cc:Subject:To:From:Date; b=B/IQVjRmP8sfSP8/V7MLjEWLx3rrOsrPd/mZhydg5iYFJuL0KyQW6coUTsgv9vi1s ddg9OURnBiPErO5xxn6YVHG0tblrf/c5QXr53RTH+EXppUxWukD0zT3g5KFijpoPov k507Q0b+Z1hoH/S74/4UT3LXGlAkLlL/jvW4tqsM= X-UI-Sender-Class: c548c8c5-30a9-4db5-a2e7-cb6cb037b8f9 Received: from [192.168.1.2] ([78.48.147.78]) by smtp.web.de (mrweb106 [213.165.67.124]) with ESMTPSA (Nemesis) id 1MJWsc-1jr4D91cmO-00K2Tf; Sat, 09 May 2020 10:00:15 +0200 Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org, Chris Mason , David Sterba , Josef Bacik Subject: Re: [PATCH 1/4] fs: btrfs: fix a data race in btrfs_block_group_done() To: Jia-Ju Bai , linux-btrfs@vger.kernel.org From: Markus Elfring Autocrypt: addr=Markus.Elfring@web.de; prefer-encrypt=mutual; keydata= mQINBFg2+xABEADBJW2hoUoFXVFWTeKbqqif8VjszdMkriilx90WB5c0ddWQX14h6w5bT/A8 +v43YoGpDNyhgA0w9CEhuwfZrE91GocMtjLO67TAc2i2nxMc/FJRDI0OemO4VJ9RwID6ltwt mpVJgXGKkNJ1ey+QOXouzlErVvE2fRh+KXXN1Q7fSmTJlAW9XJYHS3BDHb0uRpymRSX3O+E2 lA87C7R8qAigPDZi6Z7UmwIA83ZMKXQ5stA0lhPyYgQcM7fh7V4ZYhnR0I5/qkUoxKpqaYLp YHBczVP+Zx/zHOM0KQphOMbU7X3c1pmMruoe6ti9uZzqZSLsF+NKXFEPBS665tQr66HJvZvY GMDlntZFAZ6xQvCC1r3MGoxEC1tuEa24vPCC9RZ9wk2sY5Csbva0WwYv3WKRZZBv8eIhGMxs rcpeGShRFyZ/0BYO53wZAPV1pEhGLLxd8eLN/nEWjJE0ejakPC1H/mt5F+yQBJAzz9JzbToU 5jKLu0SugNI18MspJut8AiA1M44CIWrNHXvWsQ+nnBKHDHHYZu7MoXlOmB32ndsfPthR3GSv jN7YD4Ad724H8fhRijmC1+RpuSce7w2JLj5cYj4MlccmNb8YUxsE8brY2WkXQYS8Ivse39MX BE66MQN0r5DQ6oqgoJ4gHIVBUv/ZwgcmUNS5gQkNCFA0dWXznQARAQABtCZNYXJrdXMgRWxm cmluZyA8TWFya3VzLkVsZnJpbmdAd2ViLmRlPokCVAQTAQgAPhYhBHDP0hzibeXjwQ/ITuU9 Figxg9azBQJYNvsQAhsjBQkJZgGABQsJCAcCBhUICQoLAgQWAgMBAh4BAheAAAoJEOU9Figx g9azcyMP/iVihZkZ4VyH3/wlV3nRiXvSreqg+pGPI3c8J6DjP9zvz7QHN35zWM++1yNek7Ar OVXwuKBo18ASlYzZPTFJZwQQdkZSV+atwIzG3US50ZZ4p7VyUuDuQQVVqFlaf6qZOkwHSnk+ CeGxlDz1POSHY17VbJG2CzPuqMfgBtqIU1dODFLpFq4oIAwEOG6fxRa59qbsTLXxyw+PzRaR LIjVOit28raM83Efk07JKow8URb4u1n7k9RGAcnsM5/WMLRbDYjWTx0lJ2WO9zYwPgRykhn2 sOyJVXk9xVESGTwEPbTtfHM+4x0n0gC6GzfTMvwvZ9G6xoM0S4/+lgbaaa9t5tT/PrsvJiob kfqDrPbmSwr2G5mHnSM9M7B+w8odjmQFOwAjfcxoVIHxC4Cl/GAAKsX3KNKTspCHR0Yag78w i8duH/eEd4tB8twcqCi3aCgWoIrhjNS0myusmuA89kAWFFW5z26qNCOefovCx8drdMXQfMYv g5lRk821ZCNBosfRUvcMXoY6lTwHLIDrEfkJQtjxfdTlWQdwr0mM5ye7vd83AManSQwutgpI q+wE8CNY2VN9xAlE7OhcmWXlnAw3MJLW863SXdGlnkA3N+U4BoKQSIToGuXARQ14IMNvfeKX NphLPpUUnUNdfxAHu/S3tPTc/E/oePbHo794dnEm57LuuQINBFg2+xABEADZg/T+4o5qj4cw nd0G5pFy7ACxk28mSrLuva9tyzqPgRZ2bdPiwNXJUvBg1es2u81urekeUvGvnERB/TKekp25 4wU3I2lEhIXj5NVdLc6eU5czZQs4YEZbu1U5iqhhZmKhlLrhLlZv2whLOXRlLwi4jAzXIZAu 76mT813jbczl2dwxFxcT8XRzk9+dwzNTdOg75683uinMgskiiul+dzd6sumdOhRZR7YBT+xC wzfykOgBKnzfFscMwKR0iuHNB+VdEnZw80XGZi4N1ku81DHxmo2HG3icg7CwO1ih2jx8ik0r riIyMhJrTXgR1hF6kQnX7p2mXe6K0s8tQFK0ZZmYpZuGYYsV05OvU8yqrRVL/GYvy4Xgplm3 DuMuC7/A9/BfmxZVEPAS1gW6QQ8vSO4zf60zREKoSNYeiv+tURM2KOEj8tCMZN3k3sNASfoG fMvTvOjT0yzMbJsI1jwLwy5uA2JVdSLoWzBD8awZ2X/eCU9YDZeGuWmxzIHvkuMj8FfX8cK/ 2m437UA877eqmcgiEy/3B7XeHUipOL83gjfq4ETzVmxVswkVvZvR6j2blQVr+MhCZPq83Ota xNB7QptPxJuNRZ49gtT6uQkyGI+2daXqkj/Mot5tKxNKtM1Vbr/3b+AEMA7qLz7QjhgGJcie qp4b0gELjY1Oe9dBAXMiDwARAQABiQI8BBgBCAAmFiEEcM/SHOJt5ePBD8hO5T0WKDGD1rMF Alg2+xACGwwFCQlmAYAACgkQ5T0WKDGD1rOYSw/+P6fYSZjTJDAl9XNfXRjRRyJSfaw6N1pA Ahuu0MIa3djFRuFCrAHUaaFZf5V2iW5xhGnrhDwE1Ksf7tlstSne/G0a+Ef7vhUyeTn6U/0m +/BrsCsBUXhqeNuraGUtaleatQijXfuemUwgB+mE3B0SobE601XLo6MYIhPh8MG32MKO5kOY hB5jzyor7WoN3ETVNQoGgMzPVWIRElwpcXr+yGoTLAOpG7nkAUBBj9n9TPpSdt/npfok9ZfL /Q+ranrxb2Cy4tvOPxeVfR58XveX85ICrW9VHPVq9sJf/a24bMm6+qEg1V/G7u/AM3fM8U2m tdrTqOrfxklZ7beppGKzC1/WLrcr072vrdiN0icyOHQlfWmaPv0pUnW3AwtiMYngT96BevfA qlwaymjPTvH+cTXScnbydfOQW8220JQwykUe+sHRZfAF5TS2YCkQvsyf7vIpSqo/ttDk4+xc Z/wsLiWTgKlih2QYULvW61XU+mWsK8+ZlYUrRMpkauN4CJ5yTpvp+Orcz5KixHQmc5tbkLWf x0n1QFc1xxJhbzN+r9djSGGN/5IBDfUqSANC8cWzHpWaHmSuU3JSAMB/N+yQjIad2ztTckZY pwT6oxng29LzZspTYUEzMz3wK2jQHw+U66qBFk8whA7B2uAU1QdGyPgahLYSOa4XAEGb6wbI FEE= Message-ID: Date: Sat, 9 May 2020 10:00:13 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.8.0 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:1tlwqMc8g4Mnq+exu4JXQPVrlV0T/nQuXVTVoAlwogzWnURg+6g mdQsGd9ebWDdIhQU8D6WNFBEOHXk5JDl7e4kfisY9NgmMyBfWNY9fgEpjDXgyp/bvYdRGLA VW279zWxVmO4EK3VBgdgxd+MRyXJmORTKGojJ9qg1LvkpiG8v+c5C4lWwSXjELtBTad+Lph 1GiYp9Y3vHFZmB6D3ntWw== X-UI-Out-Filterresults: notjunk:1;V03:K0:IL4ulCApXVA=:axd6i3FmjB7fPueRGR+Ixe /KEwzjIySvIJjwRQ8UW1xkrbjxlzzjnqw+HpQYIgVRXA896uX5uSnf4c9Sr7PggjUr6NJI41J QiqkyCEM71ouok+FCGXhcFrGHRBzZv+2hkrcxC4vMYjJbHl5LTTmidg0fvsS5nKWcfCApSLvw NMJG9cO+JGkagXefquWAlC/5Dc1APhBr5hsFYcfc1/TVA6ud41UiS5r4y1z3LZ0MYvtbW42bF 7U9HeRGOVOWvy9cAYdWMXlv9DkHLndqq6JXTqgX0DGKrZbSpPmxRPJJ7tD6AAQH9W4Y5rY9/U ylg6UVQIMmPtdLBxOBkJqeMgqG4MgRH9K7jVIcf1GV797xJ8DokuMH0d+VLTd7M1uWpuCU5Kg Wrc+Z5ASLm9KTk4wu/kH3En84wjCxKX6+OuYY1ycTTwYg3rDm/Pk48l8v62qnXb/dN4yyN/1F ZRUMRiilYKLkhk3LfmtueZw1XKXnptWtmlNFFjsq5W0SG6agNuU7kkB7Z/u9946IkSVJly3IK ptzj3SCIzT8DtiHyU7g3xv+HWa+epkSntSIXrnoCtBvoqAeXT56YhsqGYhrs+fQIgnPNZGdv/ ifu657/S053UxPZQLUN9OfemvAQHyyMUaQtdJdL3s/sufl4j2SkqWy059LCxT3mP/LgAQgm/h otEwViu1hURGkDMDEmFvJVInzbT2TQSHoL0dE6A90P7zA0v/FtVrEMMYjl9mfbpvo2wKkUk/p zZRo85lkjXVtVfC5MxUAXjPJ4XAAoGej70WNF3PIu44XKqeavde4JIAirZioF+MLKPYWG4xg+ tYA+0f4jljsn6aXooIedsOmGymr2tMHmaTXM/KZ8wXIEaOMYt+5LpsNAsF0NzDKfdwtNux3F/ gr9+AhATIiPrkQtlY3Hth8yhwZxgOkqyLrq1fh24c1XQvOxRNxRMfX+ijPbYM5QEjh9S9z/Z5 aWewm+nmPmXKr1J1d0GpDcTlFvvYeM5YOyiYVLLJR1A2o0CijA3C8FgrVdyh5vi4m51NrNrE3 FzC1FvYI+EYjfOjA/55mvWjRnWtPSrdPPRWHtDwi4k6v9xP19TFxuO5A4FQUnJtcaYz/qX5oS oxAiHgSoQULxHkUbMXId6QRZGnMQPqNNq7o6MVRcwGvJSIYwaRWSCBg+tX6PK8asFutcfwhoD G8fLw8KdV0XEoOY4htPDTMKkJ4F4dJwj5xRflpw5GdjEabT/LDKXl+3CxQASIWaxjMQS+kFpF FYo5hlNEGjaoWwN3q Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > To fix this race, the spinlock cache->lock is used to protect the > access to cache->cached in btrfs_block_group_done(). How do you think about to replace this wording by a variant like the follo= wing? Thus use the spin lock =E2=80=9Ccache->lock=E2=80=9D to protect the acc= ess to the data structure member =E2=80=9Ccached=E2=80=9D in the implementatio= n of the function =E2=80=9Cbtrfs_block_group_done=E2=80=9D. Would you like to add the tag =E2=80=9CFixes=E2=80=9D to the change descri= ption? Regards, Markus