On 2018/12/2 下午5:03, Patrick Dijkgraaf wrote: > Hi Qu, > > Thanks for helping me! > > Please see the reponses in-line. > Any suggestions based on this? > > Thanks! > > > On Sat, 2018-12-01 at 07:57 +0800, Qu Wenruo wrote: >> On 2018/11/30 下午9:53, Patrick Dijkgraaf wrote: >>> Hi all, >>> >>> I have been a happy BTRFS user for quite some time. But now I'm >>> facing >>> a potential ~45TB dataloss... :-( >>> I hope someone can help! >>> >>> I have Server A and Server B. Both having a 20-devices BTRFS RAID6 >>> filesystem. Because of known RAID5/6 risks, Server B was a backup >>> of >>> Server A. >>> After applying updates to server B and reboot, the FS would not >>> mount >>> anymore. Because it was "just" a backup. I decided to recreate the >>> FS >>> and perform a new backup. Later, I discovered that the FS was not >>> broken, but I faced this issue: >>> https://patchwork.kernel.org/patch/10694997/ >>> >> >> Sorry for the inconvenience. >> >> I didn't realize the max_chunk_size limit isn't reliable at that >> timing. > > No problem, I should not have jumped to the conclusion to recreate the > backup volume. > >>> Anyway, the FS was already recreated, so I needed to do a new >>> backup. >>> During the backup (using rsync -vah), Server A (the source) >>> encountered >>> an I/O error and my rsync failed. In an attempt to "quick fix" the >>> issue, I rebooted Server A after which the FS would not mount >>> anymore. >> >> Did you have any dmesg about that IO error? > > Yes there was. But I omitted capturing it... The system is now rebooted > and I can't retrieve it anymore. :-( > >> And how is the reboot scheduled? Forced power off or normal reboot >> command? > > The system was rebooted using a normal reboot command.
Then the problem is pretty serious. Possibly already corrupted before. > >>> I documented what I have tried, below. I have not yet tried >>> anything >>> except what is shown, because I am afraid of causing more harm to >>> the FS. >> >> Pretty clever, no btrfs check --repair is a pretty good move. >> >>> I hope somebody here can give me advice on how to (hopefully) >>> retrieve my data... >>> >>> Thanks in advance! >>> >>> ========================================== >>> >>> [root@cornelis ~]# btrfs fi show >>> Label: 'cornelis-btrfs' uuid: ac643516-670e-40f3-aa4c-f329fc3795fd >>> Total devices 1 FS bytes used 463.92GiB >>> devid 1 size 800.00GiB used 493.02GiB path >>> /dev/mapper/cornelis-cornelis--btrfs >>> >>> Label: 'data' uuid: 4c66fa8b-8fc6-4bba-9d83-02a2a1d69ad5 >>> Total devices 20 FS bytes used 44.85TiB >>> devid 1 size 3.64TiB used 3.64TiB path /dev/sdn2 >>> devid 2 size 3.64TiB used 3.64TiB path /dev/sdp2 >>> devid 3 size 3.64TiB used 3.64TiB path /dev/sdu2 >>> devid 4 size 3.64TiB used 3.64TiB path /dev/sdx2 >>> devid 5 size 3.64TiB used 3.64TiB path /dev/sdh2 >>> devid 6 size 3.64TiB used 3.64TiB path /dev/sdg2 >>> devid 7 size 3.64TiB used 3.64TiB path /dev/sdm2 >>> devid 8 size 3.64TiB used 3.64TiB path /dev/sdw2 >>> devid 9 size 3.64TiB used 3.64TiB path /dev/sdj2 >>> devid 10 size 3.64TiB used 3.64TiB path /dev/sdt2 >>> devid 11 size 3.64TiB used 3.64TiB path /dev/sdk2 >>> devid 12 size 3.64TiB used 3.64TiB path /dev/sdq2 >>> devid 13 size 3.64TiB used 3.64TiB path /dev/sds2 >>> devid 14 size 3.64TiB used 3.64TiB path /dev/sdf2 >>> devid 15 size 7.28TiB used 588.80GiB path /dev/sdr2 >>> devid 16 size 7.28TiB used 588.80GiB path /dev/sdo2 >>> devid 17 size 7.28TiB used 588.80GiB path /dev/sdv2 >>> devid 18 size 7.28TiB used 588.80GiB path /dev/sdi2 >>> devid 19 size 7.28TiB used 588.80GiB path /dev/sdl2 >>> devid 20 size 7.28TiB used 588.80GiB path /dev/sde2 >>> >>> [root@cornelis ~]# mount /dev/sdn2 /mnt/data >>> mount: /mnt/data: wrong fs type, bad option, bad superblock on >>> /dev/sdn2, missing codepage or helper program, or other error. >> >> What is the dmesg of the mount failure? > > [Sun Dec 2 09:41:08 2018] BTRFS info (device sdn2): disk space caching > is enabled > [Sun Dec 2 09:41:08 2018] BTRFS info (device sdn2): has skinny extents > [Sun Dec 2 09:41:08 2018] BTRFS error (device sdn2): parent transid > verify failed on 46451963543552 wanted 114401 found 114173 > [Sun Dec 2 09:41:08 2018] BTRFS critical (device sdn2): corrupt leaf: > root=2 block=46451963543552 slot=0, unexpected item end, have > 1387359977 expect 16283 OK, this shows that one of the copy has mismatched generation while the other copy is completely corrupted. > [Sun Dec 2 09:41:08 2018] BTRFS warning (device sdn2): failed to read > tree root > [Sun Dec 2 09:41:08 2018] BTRFS error (device sdn2): open_ctree failed > >> And have you tried -o ro,degraded ? > > Tried it just now, gives the exact same error. > >>> [root@cornelis ~]# btrfs check /dev/sdn2 >>> Opening filesystem to check... >>> parent transid verify failed on 46451963543552 wanted 114401 found >>> 114173 >>> parent transid verify failed on 46451963543552 wanted 114401 found >>> 114173 >>> checksum verify failed on 46451963543552 found A8F2A769 wanted >>> 4C111ADF >>> checksum verify failed on 46451963543552 found 32153BE8 wanted >>> 8B07ABE4 >>> checksum verify failed on 46451963543552 found 32153BE8 wanted >>> 8B07ABE4 >>> bad tree block 46451963543552, bytenr mismatch, >>> want=46451963543552, >>> have=75208089814272 >>> Couldn't read tree root >> >> Would you please also paste the output of "btrfs ins dump-super >> /dev/sdn2" ? > > [root@cornelis ~]# btrfs ins dump-super /dev/sdn2 > superblock: bytenr=65536, device=/dev/sdn2 > --------------------------------------------------------- > csum_type 0 (crc32c) > csum_size 4 > csum 0x51725c39 [match] > bytenr 65536 > flags 0x1 > ( WRITTEN ) > magic _BHRfS_M [match] > fsid 4c66fa8b-8fc6-4bba-9d83-02a2a1d69ad5 > label data > generation 114401 > root 46451963543552 The bytenr matches with the dmesg, so it's tree root node corrupted. > sys_array_size 513 > chunk_root_generation 112769 > root_level 1 > chunk_root 22085632 > chunk_root_level 1 > log_root 46451935461376 > log_root_transid 0 > log_root_level 0 > total_bytes 104020314161152 > bytes_used 49308554543104 > sectorsize 4096 > nodesize 16384 > leafsize (deprecated) 16384 > stripesize 4096 > root_dir 6 > num_devices 20 > compat_flags 0x0 > compat_ro_flags 0x0 > incompat_flags 0x1e1 > ( MIXED_BACKREF | > BIG_METADATA | > EXTENDED_IREF | > RAID56 | > SKINNY_METADATA ) > cache_generation 114401 > uuid_tree_generation 114401 > dev_item.uuid c6b44903-e849-4403-98c4-f3ba4d0b3fc3 > dev_item.fsid 4c66fa8b-8fc6-4bba-9d83-02a2a1d69ad5 [match] > dev_item.type 0 > dev_item.total_bytes 4000783007744 > dev_item.bytes_used 4000781959168 > dev_item.io_align 4096 > dev_item.io_width 4096 > dev_item.sector_size 4096 > dev_item.devid 1 > dev_item.dev_group 0 > dev_item.seek_speed 0 > dev_item.bandwidth 0 > dev_item.generation 0 > >> It looks like your tree root (or at least some tree root nodes/leaves >> get corrupted) >> >>> ERROR: cannot open file system >> >> And since it's your tree root corrupted, you could also try >> "btrfs-find-root <device>" to try to get a good old copy of your tree >> root. > > The output is rather long. I pasted it here: > https://pastebin.com/FkyBLgj9 > I'm unsure what to look for in this output? This shows all the candidates of the older tree root bytenr. We could use it to try to recover. You could then try the following command and see if btrfs check can go further. # btrfs check -r 45462239363072 <device> And the following dump could also help: # btrfs ins dump-tree -b 45462239363072 --follow Thanks, Qu > >> But I suspect the corruption happens before you noticed, thus the old >> tree root may not help much. >> >> Also, the output of "btrfs ins dump-tree -t root <device>" will help. > > Here it is: > > [root@cornelis ~]# btrfs ins dump-tree -t root /dev/sdn2 > btrfs-progs v4.19 > parent transid verify failed on 46451963543552 wanted 114401 found > 114173 > parent transid verify failed on 46451963543552 wanted 114401 found > 114173 > checksum verify failed on 46451963543552 found A8F2A769 wanted 4C111ADF > checksum verify failed on 46451963543552 found 32153BE8 wanted 8B07ABE4 > checksum verify failed on 46451963543552 found 32153BE8 wanted 8B07ABE4 > bad tree block 46451963543552, bytenr mismatch, want=46451963543552, > have=75208089814272 > Couldn't read tree root > ERROR: unable to open /dev/sdn2 > >> Thanks, >> Qu > > No, thank YOU! :-) > >>> [root@cornelis ~]# btrfs restore /dev/sdn2 /mnt/data/ >>> parent transid verify failed on 46451963543552 wanted 114401 found >>> 114173 >>> parent transid verify failed on 46451963543552 wanted 114401 found >>> 114173 >>> checksum verify failed on 46451963543552 found A8F2A769 wanted >>> 4C111ADF >>> checksum verify failed on 46451963543552 found 32153BE8 wanted >>> 8B07ABE4 >>> checksum verify failed on 46451963543552 found 32153BE8 wanted >>> 8B07ABE4 >>> bad tree block 46451963543552, bytenr mismatch, >>> want=46451963543552, >>> have=75208089814272 >>> Couldn't read tree root >>> Could not open root, trying backup super >>> warning, device 14 is missing >>> warning, device 13 is missing >>> warning, device 12 is missing >>> warning, device 11 is missing >>> warning, device 10 is missing >>> warning, device 9 is missing >>> warning, device 8 is missing >>> warning, device 7 is missing >>> warning, device 6 is missing >>> warning, device 5 is missing >>> warning, device 4 is missing >>> warning, device 3 is missing >>> warning, device 2 is missing >>> checksum verify failed on 22085632 found 5630EA32 wanted 1AA6FFF0 >>> checksum verify failed on 22085632 found 5630EA32 wanted 1AA6FFF0 >>> bad tree block 22085632, bytenr mismatch, want=22085632, >>> have=1147797504 >>> ERROR: cannot read chunk root >>> Could not open root, trying backup super >>> warning, device 14 is missing >>> warning, device 13 is missing >>> warning, device 12 is missing >>> warning, device 11 is missing >>> warning, device 10 is missing >>> warning, device 9 is missing >>> warning, device 8 is missing >>> warning, device 7 is missing >>> warning, device 6 is missing >>> warning, device 5 is missing >>> warning, device 4 is missing >>> warning, device 3 is missing >>> warning, device 2 is missing >>> checksum verify failed on 22085632 found 5630EA32 wanted 1AA6FFF0 >>> checksum verify failed on 22085632 found 5630EA32 wanted 1AA6FFF0 >>> bad tree block 22085632, bytenr mismatch, want=22085632, >>> have=1147797504 >>> ERROR: cannot read chunk root >>> Could not open root, trying backup super >>> >>> [root@cornelis ~]# uname -r >>> 4.18.16-arch1-1-ARCH >>> >>> [root@cornelis ~]# btrfs --version >>> btrfs-progs v4.19 >>>
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