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Fri, 3 Sep 2021 03:08:27 +0000 Subject: Re: [PATCH RFC V5 2/2] btrfs: consolidate device_list_mutex in prepare_sprout to its parent To: Nikolay Borisov , dsterba@suse.com Cc: l@damenly.su, linux-btrfs@vger.kernel.org References: From: Anand Jain Message-ID: <4f4e36cc-d377-abde-2df3-759f85867482@oracle.com> Date: Fri, 3 Sep 2021 11:08:19 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.13.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-ClientProxiedBy: SG2PR02CA0049.apcprd02.prod.outlook.com (2603:1096:4:54::13) To MN2PR10MB4128.namprd10.prod.outlook.com (2603:10b6:208:1d2::24) MIME-Version: 1.0 Received: from [192.168.10.109] (39.109.186.25) by SG2PR02CA0049.apcprd02.prod.outlook.com (2603:1096:4:54::13) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4478.17 via Frontend Transport; Fri, 3 Sep 2021 03:08:25 +0000 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: 5692399d-0695-4c29-11c5-08d96e881950 X-MS-TrafficTypeDiagnostic: MN2PR10MB3838: X-Microsoft-Antispam-PRVS: X-MS-Oob-TLC-OOBClassifiers: OLM:8273; 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But they are holding it sequentially, thus creates a >> small window to an opportunity to race. Close this opportunity and hold >> device_list_mutex common to both btrfs_init_new_device() and >> btrfs_prepare_sprout(). >> >> Signed-off-by: Anand Jain > > That's a moot point, what's important is that btrfs_prepare_sprout > leaves the fs_devices in a consistent state and btrfs_init_new_device > also takes the lock when it's about to modify the devices list, so > that's fine as well. While the patch itself won't do any harm I think > it's irrelevant. This patch is for the cleanup of the device_list_mutex. Thanks, Anand