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Mon, 10 Aug 2020 08:21:50 +0000 (UTC) Subject: Re: raid10 corruption while removing failing disk To: =?UTF-8?Q?Agust=c3=adn_Dall=ca=bcAlba?= , linux-btrfs@vger.kernel.org References: <3dc4d28e81b3336311c979bda35ceb87b9645606.camel@dallalba.com.ar> From: Nikolay Borisov Autocrypt: addr=nborisov@suse.com; prefer-encrypt=mutual; keydata= xsFNBFiKBz4BEADNHZmqwhuN6EAzXj9SpPpH/nSSP8YgfwoOqwrP+JR4pIqRK0AWWeWCSwmZ T7g+RbfPFlmQp+EwFWOtABXlKC54zgSf+uulGwx5JAUFVUIRBmnHOYi/lUiE0yhpnb1KCA7f u/W+DkwGerXqhhe9TvQoGwgCKNfzFPZoM+gZrm+kWv03QLUCr210n4cwaCPJ0Nr9Z3c582xc bCUVbsjt7BN0CFa2BByulrx5xD9sDAYIqfLCcZetAqsTRGxM7LD0kh5WlKzOeAXj5r8DOrU2 GdZS33uKZI/kZJZVytSmZpswDsKhnGzRN1BANGP8sC+WD4eRXajOmNh2HL4P+meO1TlM3GLl EQd2shHFY0qjEo7wxKZI1RyZZ5AgJnSmehrPCyuIyVY210CbMaIKHUIsTqRgY5GaNME24w7h TyyVCy2qAM8fLJ4Vw5bycM/u5xfWm7gyTb9V1TkZ3o1MTrEsrcqFiRrBY94Rs0oQkZvunqia c+NprYSaOG1Cta14o94eMH271Kka/reEwSZkC7T+o9hZ4zi2CcLcY0DXj0qdId7vUKSJjEep c++s8ncFekh1MPhkOgNj8pk17OAESanmDwksmzh1j12lgA5lTFPrJeRNu6/isC2zyZhTwMWs k3LkcTa8ZXxh0RfWAqgx/ogKPk4ZxOXQEZetkEyTFghbRH2BIwARAQABzSJOaWtvbGF5IEJv cmlzb3YgPG5ib3Jpc292QHN1c2UuZGU+wsF4BBMBAgAiBQJYijkSAhsDBgsJCAcDAgYVCAIJ CgsEFgIDAQIeAQIXgAAKCRBxvoJG5T8oV/B6D/9a8EcRPdHg8uLEPywuJR8URwXzkofT5bZE IfGF0Z+Lt2ADe+nLOXrwKsamhweUFAvwEUxxnndovRLPOpWerTOAl47lxad08080jXnGfYFS Dc+ew7C3SFI4tFFHln8Y22Q9075saZ2yQS1ywJy+TFPADIprAZXnPbbbNbGtJLoq0LTiESnD w/SUC6sfikYwGRS94Dc9qO4nWyEvBK3Ql8NkoY0Sjky3B0vL572Gq0ytILDDGYuZVo4alUs8 LeXS5ukoZIw1QYXVstDJQnYjFxYgoQ5uGVi4t7FsFM/6ykYDzbIPNOx49Rbh9W4uKsLVhTzG BDTzdvX4ARl9La2kCQIjjWRg+XGuBM5rxT/NaTS78PXjhqWNYlGc5OhO0l8e5DIS2tXwYMDY LuHYNkkpMFksBslldvNttSNei7xr5VwjVqW4vASk2Aak5AleXZS+xIq2FADPS/XSgIaepyTV tkfnyreep1pk09cjfXY4A7qpEFwazCRZg9LLvYVc2M2eFQHDMtXsH59nOMstXx2OtNMcx5p8 0a5FHXE/HoXz3p9bD0uIUq6p04VYOHsMasHqHPbsMAq9V2OCytJQPWwe46bBjYZCOwG0+x58 fBFreP/NiJNeTQPOa6FoxLOLXMuVtpbcXIqKQDoEte9aMpoj9L24f60G4q+pL/54ql2VRscK d87BTQRYigc+ARAAyJSq9EFk28++SLfg791xOh28tLI6Yr8wwEOvM3wKeTfTZd+caVb9gBBy wxYhIopKlK1zq2YP7ZjTP1aPJGoWvcQZ8fVFdK/1nW+Z8/NTjaOx1mfrrtTGtFxVBdSCgqBB jHTnlDYV1R5plJqK+ggEP1a0mr/rpQ9dFGvgf/5jkVpRnH6BY0aYFPprRL8ZCcdv2DeeicOO YMobD5g7g/poQzHLLeT0+y1qiLIFefNABLN06Lf0GBZC5l8hCM3Rpb4ObyQ4B9PmL/KTn2FV Xq/c0scGMdXD2QeWLePC+yLMhf1fZby1vVJ59pXGq+o7XXfYA7xX0JsTUNxVPx/MgK8aLjYW hX+TRA4bCr4uYt/S3ThDRywSX6Hr1lyp4FJBwgyb8iv42it8KvoeOsHqVbuCIGRCXqGGiaeX Wa0M/oxN1vJjMSIEVzBAPi16tztL/wQtFHJtZAdCnuzFAz8ue6GzvsyBj97pzkBVacwp3/Mw qbiu7sDz7yB0d7J2tFBJYNpVt/Lce6nQhrvon0VqiWeMHxgtQ4k92Eja9u80JDaKnHDdjdwq FUikZirB28UiLPQV6PvCckgIiukmz/5ctAfKpyYRGfez+JbAGl6iCvHYt/wAZ7Oqe/3Cirs5 KhaXBcMmJR1qo8QH8eYZ+qhFE3bSPH446+5oEw8A9v5oonKV7zMAEQEAAcLBXwQYAQIACQUC WIoHPgIbDAAKCRBxvoJG5T8oV1pyD/4zdXdOL0lhkSIjJWGqz7Idvo0wjVHSSQCbOwZDWNTN JBTP0BUxHpPu/Z8gRNNP9/k6i63T4eL1xjy4umTwJaej1X15H8Hsh+zakADyWHadbjcUXCkg OJK4NsfqhMuaIYIHbToi9K5pAKnV953xTrK6oYVyd/Rmkmb+wgsbYQJ0Ur1Ficwhp6qU1CaJ mJwFjaWaVgUERoxcejL4ruds66LM9Z1Qqgoer62ZneID6ovmzpCWbi2sfbz98+kW46aA/w8r 7sulgs1KXWhBSv5aWqKU8C4twKjlV2XsztUUsyrjHFj91j31pnHRklBgXHTD/pSRsN0UvM26 lPs0g3ryVlG5wiZ9+JbI3sKMfbdfdOeLxtL25ujs443rw1s/PVghphoeadVAKMPINeRCgoJH zZV/2Z/myWPRWWl/79amy/9MfxffZqO9rfugRBORY0ywPHLDdo9Kmzoxoxp9w3uTrTLZaT9M KIuxEcV8wcVjr+Wr9zRl06waOCkgrQbTPp631hToxo+4rA1jiQF2M80HAet65ytBVR2pFGZF zGYYLqiG+mpUZ+FPjxk9kpkRYz61mTLSY7tuFljExfJWMGfgSg1OxfLV631jV1TcdUnx+h3l Sqs2vMhAVt14zT8mpIuu2VNxcontxgVr1kzYA/tQg32fVRbGr449j1gw57BV9i0vww== Message-ID: <4c967884-2252-a21d-a994-80df64a7e6ef@suse.com> Date: Mon, 10 Aug 2020 11:21:29 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <3dc4d28e81b3336311c979bda35ceb87b9645606.camel@dallalba.com.ar> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On 10.08.20 г. 10:03 ч., Agustín DallʼAlba wrote: > Hello! > > The last quarterly scrub on our btrfs filesystem found a few bad > sectors in one of its devices (/dev/sdd), and because there's nobody on > site to replace the failing disk I decided to remove it from the array > with `btrfs device remove` before the problem could get worse. > > The removal was going relatively well (although slowly and I had to > reboot a few times due to the bad sectors) until it had about 200 GB > left to move. Now the filesystem turns read only when I try to finish > the removal and `btrfs check` complains about wrong metadata checksums. > However as far as I can tell none of the copies of the corrupt data are > in the failing disk. > > How could this happen? Is it possible to fix this filesystem? > > I have refrained from trying anything so far, like upgrading to a newer > kernel or disconnecting the failing drive, before confirming with you > that it's safe. > > Kind regards. > > > # uname -a > Linux susanita 4.15.0-111-generic #112-Ubuntu SMP Thu Jul 9 20:32:34 > UTC 2020 x86_64 x86_64 x86_64 GNU/Linux > > > # btrfs --version > btrfs-progs v4.15.1 > > > # btrfs fi show > Label: 'Susanita' uuid: 4d3acf20-d408-49ab-b0a6-182396a9f27c > Total devices 5 FS bytes used 4.90TiB > devid 1 size 3.64TiB used 3.42TiB path /dev/sda > devid 2 size 3.64TiB used 3.42TiB path /dev/sde > devid 3 size 1.82TiB used 1.59TiB path /dev/sdb > devid 5 size 0.00B used 185.50GiB path /dev/sdd > devid 6 size 1.82TiB used 1.22TiB path /dev/sdc > > > # btrfs fi df / > Data, RAID1: total=4.90TiB, used=4.90TiB > System, RAID10: total=64.00MiB, used=880.00KiB > Metadata, RAID10: total=9.00GiB, used=7.57GiB > GlobalReserve, single: total=512.00MiB, used=0.00B > > > # btrfs check --force --readonly /dev/sda > WARNING: filesystem mounted, continuing because of --force > Checking filesystem on /dev/sda > UUID: 4d3acf20-d408-49ab-b0a6-182396a9f27c > checksum verify failed on 10919566688256 found BAB1746E wanted A8A48266 > checksum verify failed on 10919566688256 found BAB1746E wanted A8A48266 > bytenr mismatch, want=10919566688256, have=17196831625821864417 > ERROR: failed to repair root items: Input/output error > > # btrfs-map-logical -l 10919566688256 /dev/sda > mirror 1 logical 10919566688256 physical 394473357312 device /dev/sdc > mirror 2 logical 10919566688256 physical 477218586624 device /dev/sda > > > Relevant dmesg output: > [ 4.963420] Btrfs loaded, crc32c=crc32c-generic > [ 5.072878] BTRFS: device label Susanita devid 6 transid 4241535 /dev/sdc > [ 5.073165] BTRFS: device label Susanita devid 3 transid 4241535 /dev/sdb > [ 5.073713] BTRFS: device label Susanita devid 2 transid 4241535 /dev/sde > [ 5.073916] BTRFS: device label Susanita devid 5 transid 4241535 /dev/sdd > [ 5.074398] BTRFS: device label Susanita devid 1 transid 4241535 /dev/sda > [ 5.152479] BTRFS info (device sda): disk space caching is enabled > [ 5.152551] BTRFS info (device sda): has skinny extents > [ 5.332538] BTRFS info (device sda): bdev /dev/sdd errs: wr 0, rd 24, flush 0, corrupt 0, gen 0 > [ 38.869423] BTRFS info (device sda): enabling auto defrag > [ 38.869490] BTRFS info (device sda): use lzo compression, level 0 > [ 38.869547] BTRFS info (device sda): disk space caching is enabled > > > After running btrfs device remove /dev/sdd /: > [ 193.684703] BTRFS info (device sda): relocating block group 10593404846080 flags metadata|raid10 > [ 312.921934] BTRFS error (device sda): bad tree block start 10597444141056 10919566688256 > [ 313.034339] BTRFS error (device sda): bad tree block start 17196831625821864417 10919566688256 > [ 313.034595] BTRFS error (device sda): bad tree block start 10597444141056 10919566688256 > [ 313.034621] BTRFS: error (device sda) in btrfs_run_delayed_refs:3083: errno=-5 IO failure > [ 313.034627] BTRFS info (device sda): forced readonly > [ 313.036328] BUG: unable to handle kernel NULL pointer dereference at 0000000000000000 > [ 313.036596] IP: merge_reloc_roots+0x19f/0x2c0 [btrfs] This suggests you are hitting a known problem with reloc roots which have been fixed in the latest upstream and lts (5.4) kernels: 044ca910276b btrfs: reloc: fix reloc root leak and NULL pointer dereference (3 months ago) 707de9c0806d btrfs: relocation: fix reloc_root lifespan and access (7 months ago) 1fac4a54374f btrfs: relocation: fix use-after-free on dead relocation roots (11 months ago) So yes, try to update to latest stable kernel and re-run the device remove. Also update your btrfs progs to latest 5.6 version and rerun check again (by default it's a read only operations so it shouldn't cause any more damage).