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Fri, 4 Oct 2019 05:08:47 -0400 Received: by zaphod.cobb.me.uk (Postfix, from userid 107) id CAF4A9C4F8; Fri, 4 Oct 2019 10:08:44 +0100 (BST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=cobb.uk.net; s=201703; t=1570180124; bh=wSdXlu5JnZVFQD/kOVDFMd6Nb0xof+ydAVmNbptjYrE=; h=Subject:To:References:From:Date:In-Reply-To:From; b=ocCpivb9fttamuPedOp+qZqt1XFQfe7aoDybHT/ThXx6B5Ssjcb2lSTsAh8XMXp5l XUzkB3FtW08a94eJYL39BTelVIp8uvPcIbWXC/XRJnzAJxZMhwSeWoylCr1uMzurCb U9yYI6lJ+7UfFip6tm7XddZ/A1YpMCwywC38eY/ZC/WVeD27I7RbBApL5mljponbT3 1qlbTuziE9huPZFUCJfWXpho4J8PexDxOK+s3m283e5Q7SBnNwj0/SVxU1lQvVNc0+ AewkkGPWguoTdwZnMBB5v4frXqenaNy1ZYIzHjLjWAk7KGTqIkpHqiFdOEdxgldV4H mmN/kDKCQdfWQ== Received: from black.home.cobb.me.uk (unknown [192.168.0.205]) by zaphod.cobb.me.uk (Postfix) with ESMTP id DB6F79C4F3; Fri, 4 Oct 2019 10:08:42 +0100 (BST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=cobb.uk.net; s=201703; t=1570180123; bh=wSdXlu5JnZVFQD/kOVDFMd6Nb0xof+ydAVmNbptjYrE=; h=Subject:To:References:From:Date:In-Reply-To:From; b=ZS1Dkx6f4qklTjOfx8pnmFwohUHKPJU+EpoSO+sHkCTb7rKgFGLGeJ7N3Hw+4JJ8l h4hnoc7C9td0TJgJfvT1v8Tcv91vqiHvve91dt5NXVM78v300HG9kEMlIOpr3crhpz 6DnB/gPi+hw2bBf0QaD+Kq8ajeAA8WAEJYBZRXaf15ovBM9vojTMMujJe85P3TjOz9 abtPvB3m/HCOoW4axJaXpScJoz15DYI6Z2tp2i2FIDIZc+MepApnirELVzkf1Idqwb kY8C/rYpoFWyBIXx9PF1ipV4grvYjKQZiTI2/q1/nPRcKX7/7WuPftWdjUG+wcBEJn 5QH2B3MsPTZiw== Received: from [192.168.0.211] (novatech.home.cobb.me.uk [192.168.0.211]) by black.home.cobb.me.uk (Postfix) with ESMTPS id A82D455A0C; Fri, 4 Oct 2019 10:08:42 +0100 (BST) Subject: Re: [Not TLS] Re: [PATCH 3/4] btrfs: include non-missing as a qualifier for the latest_bdev To: Nikolay Borisov , Anand Jain , linux-btrfs@vger.kernel.org References: <1570175403-4073-1-git-send-email-anand.jain@oracle.com> <1570175403-4073-4-git-send-email-anand.jain@oracle.com> <93c711f8-dc77-dcc2-52b0-fc46487ff16e@suse.com> From: Graham Cobb Openpgp: preference=signencrypt Autocrypt: addr=g.btrfs@cobb.uk.net; prefer-encrypt=mutual; keydata= mQINBFaetnIBEAC5cHHbXztbmZhxDof6rYh/Dd5otxJXZ1p7cjE2GN9hCH7gQDOq5EJNqF9c VtD9rIywYT1i3qpHWyWo0BIwkWvr1TyFd3CioBe7qfo/8QoeA9nnXVZL2gcorI85a2GVRepb kbE22X059P1Z1Cy7c29dc8uDEzAucCILyfrNdZ/9jOTDN9wyyHo4GgPnf9lW3bKqF+t//TSh SOOis2+xt60y2In/ls29tD3G2ANcyoKF98JYsTypKJJiX07rK3yKTQbfqvKlc1CPWOuXE2x8 DdI3wiWlKKeOswdA2JFHJnkRjfrX9AKQm9Nk5JcX47rLxnWMEwlBJbu5NKIW5CUs/5UYqs5s 0c6UZ3lVwinFVDPC/RO8ixVwDBa+HspoSDz1nJyaRvTv6FBQeiMISeF/iRKnjSJGlx3AzyET ZP8bbLnSOiUbXP8q69i2epnhuap7jCcO38HA6qr+GSc7rpl042mZw2k0bojfv6o0DBsS/AWC DPFExfDI63On6lUKgf6E9vD3hvr+y7FfWdYWxauonYI8/i86KdWB8yaYMTNWM/+FAKfbKRCP dMOMnw7bTbUJMxN51GknnutQlB3aDTz4ze/OUAsAOvXEdlDYAj6JqFNdZW3k9v/QuQifTslR JkqVal4+I1SUxj8OJwQWOv/cAjCKJLr5g6UfUIH6rKVAWjEx+wARAQABtDNHcmFoYW0gQ29i YiAoUGVyc29uYWwgYWRkcmVzcykgPGdyYWhhbUBjb2JiLnVrLm5ldD6JAlEEEwECADsCGwEG CwkIBwMCBhUIAgkKCwQWAgMBAh4BAheAAhkBBQJWnr9UFRhoa3A6Ly9rZXlzLmdudXBnLm5l dAAKCRBv35GGXfm3Tte8D/45+/dnVdvzPsKgnrdoXpmvhImGaSctn9bhAKvng7EkrQjgV3cf C9GMgK0vEJu+4f/sqWA7hPKUq/jW5vRETcvqEp7v7z+56kqq5LUQE5+slsEb/A4lMP4ppwd+ TPwwDrtVlKNqbKJOM0kPkpj7GRy3xeOYh9D7DtFj2vlmaAy6XvKav/UUU4PoUdeCRyZCRfl0 Wi8pQBh0ngQWfW/VqI7VsG3Qov5Xt7cTzLuP/PhvzM2c5ltZzEzvz7S/jbB1+pnV9P7WLMYd EjhCYzJweCgXyQHCaAWGiHvBOpmxjbHXwX/6xTOJA5CGecDeIDjiK3le7ubFwQAfCgnmnzEj pDG+3wq7co7SbtGLVM3hBsYs27M04Oi2aIDUN1RSb0vsB6c07ECT52cggIZSOCvntl6n+uMl p0WDrl1i0mJUbztQtDzGxM7nw+4pJPV4iX1jJYbWutBwvC+7F1n2F6Niu/Y3ew9a3ixV2+T6 aHWkw7/VQvXGnLHfcFbIbzNoAvI6RNnuEqoCnZHxplEr7LuxLR41Z/XAuCkvK41N/SOI9zzT GLgUyQVOksdbPaxTgBfah9QlC9eXOKYdw826rGXQsvG7h67nqi67bp1I5dMgbM/+2quY9xk0 hkWSBKFP7bXYu4kjXZUaYsoRFEfL0gB53eF21777/rR87dEhptCnaoXeqbkBDQRWnrnDAQgA 0fRG36Ul3Y+iFs82JPBHDpFJjS/wDK+1j7WIoy0nYAiciAtfpXB6hV+fWurdjmXM4Jr8x73S xHzmf9yhZSTn3nc5GaK/jjwy3eUdoXu9jQnBIIY68VbgGaPdtD600QtfWt2zf2JC+3CMIwQ2 fK6joG43sM1nXiaBBHrr0IadSlas1zbinfMGVYAd3efUxlIUPpUK+B1JA12ZCD2PCTdTmVDe DPEsYZKuwC8KJt60MjK9zITqKsf21StwFe9Ak1lqX2DmJI4F12FQvS/E3UGdrAFAj+3HGibR yfzoT+w9UN2tHm/txFlPuhGU/LosXYCxisgNnF/R4zqkTC1/ao7/PQARAQABiQIlBBgBAgAP BQJWnrnDAhsMBQkJZgGAAAoJEG/fkYZd+bdO9b4P/0y3ADmZkbtme4+Bdp68uisDzfI4c/qo XSLTxY122QRVNXxn51yRRTzykHtv7/Zd/dUD5zvwj2xXBt9wk4V060wtqh3lD6DE5mQkCVar eAfHoygGMG+/mJDUIZD56m5aXN5Xiq77SwTeqJnzc/lYAyZXnTAWfAecVSdLQcKH21p/0AxW GU9+IpIjt8XUEGThPNsCOcdemC5u0I1ZeVRXAysBj2ymH0L3EW9B6a0airCmJ3Yctm0maqy+ 2MQ0Q6Jw8DWXbwynmnmzLlLEaN8wwAPo5cb3vcNM3BTcWMaEUHRlg82VR2O+RYpbXAuPOkNo 6K8mxta3BoZt3zYGwtqc/cpVIHpky+e38/5yEXxzBNn8Rn1xD6pHszYylRP4PfolcgMgi0Ny 72g40029WqQ6B7bogswoiJ0h3XTX7ipMtuVIVlf+K7r6ca/pX2R9B/fWNSFqaP4v0qBpyJdJ LO/FP87yHpEDbbKQKW6Guf6/TKJ7iaG3DDpE7CNCNLfFG/skhrh5Ut4zrG9SjA+0oDkfZ4dI B8+QpH3mP9PxkydnxGiGQxvLxI5Q+vQa+1qA5TcCM9SlVLVGelR2+Wj2In+t2GgigTV3PJS4 tMlN++mrgpjfq4DMYv1AzIBi6/bSR6QGKPYYOOjbk+8Sfao0fmjQeOhj1tAHZuI4hoQbowR+ myxb Message-ID: <8f0fd5a3-c389-b39a-6f22-a17e25cff481@cobb.uk.net> Date: Fri, 4 Oct 2019 10:08:42 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <93c711f8-dc77-dcc2-52b0-fc46487ff16e@suse.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: 8bit Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On 04/10/2019 09:11, Nikolay Borisov wrote: > > > On 4.10.19 г. 10:50 ч., Anand Jain wrote: >> btrfs_free_extra_devids() reorgs fs_devices::latest_bdev >> to point to the bdev with greatest device::generation number. >> For a typical-missing device the generation number is zero so >> fs_devices::latest_bdev will never point to it. >> >> But if the missing device is due to alienating [1], then >> device::generation is not-zero and if it is >= to rest of >> device::generation in the list, then fs_devices::latest_bdev >> ends up pointing to the missing device and reports the error >> like this [2] >> >> [1] >> mkfs.btrfs -fq /dev/sdd && mount /dev/sdd /btrfs >> mkfs.btrfs -fq -draid1 -mraid1 /dev/sdb /dev/sdc >> sleep 3 # avoid racing with udev's useless scans if needed >> btrfs dev add -f /dev/sdb /btrfs > > Hm, here I think the correct way is to refuse adding /dev/sdb to an > existing fs if it's detected to be part of a different one. I.e it > should require wipefs to be done. I disagree. -f means "force overwrite of existing filesystem on the given disk(s)". It shouldn't be any different whether the existing fs is btrfs or something else. Graham