Re: Repair broken btrfs raid6?

[Tobias Holst <tobby@tobby.eu>]

Hi

I don't remember the exact mkfs.btrfs options anymore but
> ls /sys/fs/btrfs/[UUID]/features/
shows the following output:
> big_metadata  compress_lzo  extended_iref  mixed_backref  raid56

I also tested my device with a short
> hdparm -tT /dev/dm5
and got
> /dev/mapper/sdc_crypt:
>  Timing cached reads:   30712 MB in  2.00 seconds = 15376.11 MB/sec
>  Timing buffered disk reads: 444 MB in  3.01 seconds = 147.51 MB/sec

Looks ok to me. Should I test more?

I bought a few new hard drives so currently I am copying all my data
to a second (faster) backup, so I can maybe overwrite the current file
system, if it's not repairable.

Regards,
Tobias


2015-02-12 10:16 GMT+01:00 Liu Bo <bo.li.liu@oracle.com>:
> On Wed, Feb 11, 2015 at 03:46:33PM +0100, Tobias Holst wrote:
>> Hmm, it looks like it is getting worse... Here are some parts of my
>> syslog, including two crashed btrfs-threads:
>>
>> So I am still getting many of these:
>> > BTRFS (device dm-5): parent transid verify failed on 25033166798848 wanted 108976 found 108958
>> > BTRFS warning (device dm-5): page private not zero on page 25033166798848
>> > BTRFS warning (device dm-5): page private not zero on page 25033166802944
>> > BTRFS warning (device dm-5): page private not zero on page 25033166807040
>> > BTRFS warning (device dm-5): page private not zero on page 25033166811136
>
> First we probably make sure that your device is well setup, since these
> messages usually occur after a drive is removed(the device is somehow droping
> writes), the below -EIO also implies btrfs cannot read/write data from or to that drive.
>
> And in theory, RAID6 can tolerate two drive failures, so what's your mkfs.btrfs option?
>
> Thanks,
>
> -liubo
>
>> > BTRFS info (device dm-5): force lzo compression
>> > BTRFS info (device dm-5): disk space caching is enabled
>> > BTRFS: dm-5 checksum verify failed on 30525304061952 wanted 55270A94 found B18E3934 level 0
>> > BTRFS: dm-5 checksum verify failed on 30525304061952 wanted 55270A94 found B18E3934 level 0
>> > BTRFS: dm-5 checksum verify failed on 30525304061952 wanted 55270A94 found B18E3934 level 0
>> > BTRFS: dm-5 checksum verify failed on 30525304061952 wanted 55270A94 found B18E3934 level 0
>> > BTRFS: dm-5 checksum verify failed on 30525304061952 wanted 55270A94 found B18E3934 level 0
>> > BTRFS: dm-5 checksum verify failed on 30525304061952 wanted 55270A94 found B18E3934 level 0
>>
>> Then there is this crash of "super"/btrfs_abort_transaction:
>> > ------------[ cut here ]------------
>> > WARNING: CPU: 0 PID: 30526 at /home/kernel/COD/linux/fs/btrfs/super.c:260 __btrfs_abort_transaction+0x5f/0x140 [btrfs]()
>> > BTRFS: Transaction aborted (error -5)
>> > Modules linked in: ufs(E) qnx4(E) hfsplus(E) hfs(E) minix(E) ntfs(E) msdos(E) jfs(E) xfs(E) libcrc32c(E) btrfs(E) xor(E) raid6_pq(E) iosf_mbi(E) dm_crypt(E) kvm_intel(E) kvm(E) crct10dif_pclmul(E) crc32_pclmul(E) ppdev(E) ghash_clmulni_intel(E) aesni_intel(E) aes_x86_64(E) lrw(E) gf128mul(E) glue_helper(E) ablk_helper(E) cryptd(E) 8250_fintek(E) serio_raw(E) virtio_rng(E) parport_pc(E) mac_hid(E) pvpanic(E) i2c_piix4(E) lp(E) parport(E) cirrus(E) syscopyarea(E) sysfillrect(E) sysimgblt(E) ttm(E) mpt2sas(E) drm_kms_helper(E) raid_class(E) floppy(E) psmouse(E) drm(E) scsi_transport_sas(E)
>> > CPU: 0 PID: 30526 Comm: kworker/u16:6 Tainted: G        W   E  3.19.0-031900-generic #201502091451
>> > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
>> > Workqueue: btrfs-extent-refs btrfs_extent_refs_helper [btrfs]
>> > 0000000000000104 ffff880002743c18 ffffffff817c4c00 0000000000000007
>> > ffff880002743c68 ffff880002743c58 ffffffff81076e87 ffff880002743c58
>> > ffff88020a8694d0 ffff8801fb715800 00000000fffffffb 0000000000000ae8
>> > Call Trace:
>> > [<ffffffff817c4c00>] dump_stack+0x45/0x57
>> > [<ffffffff81076e87>] warn_slowpath_common+0x97/0xe0
>> > [<ffffffff81076f86>] warn_slowpath_fmt+0x46/0x50
>> > [<ffffffffc06375cf>] __btrfs_abort_transaction+0x5f/0x140 [btrfs]
>> > [<ffffffffc0655105>] btrfs_run_delayed_refs.part.82+0x175/0x290 [btrfs]
>> > [<ffffffffc0655237>] btrfs_run_delayed_refs+0x17/0x20 [btrfs]
>> > [<ffffffffc0655507>] delayed_ref_async_start+0x37/0x90 [btrfs]
>> > [<ffffffffc069720e>] normal_work_helper+0x7e/0x1b0 [btrfs]
>> > [<ffffffffc0697572>] btrfs_extent_refs_helper+0x12/0x20 [btrfs]
>> > [<ffffffff8108f76d>] process_one_work+0x14d/0x460
>> > [<ffffffff8109014b>] worker_thread+0x11b/0x3f0
>> > [<ffffffff81090030>] ? create_worker+0x1e0/0x1e0
>> > [<ffffffff81095d59>] kthread+0xc9/0xe0
>> > [<ffffffff81095c90>] ? flush_kthread_worker+0x90/0x90
>> > [<ffffffff817d1e7c>] ret_from_fork+0x7c/0xb0
>> > [<ffffffff81095c90>] ? flush_kthread_worker+0x90/0x90
>> > ---[ end trace dd65465954546462 ]---
>> > BTRFS: error (device dm-5) in btrfs_run_delayed_refs:2792: errno=-5 IO failure
>> > BTRFS info (device dm-5): forced readonly
>>
>> and this crash of "delayed-ref"/btrfs_select_ref_head:
>> > ------------[ cut here ]------------
>> > WARNING: CPU: 7 PID: 3159 at /home/kernel/COD/linux/fs/btrfs/delayed-ref.c:438 btrfs_select_ref_head+0x120/0x130 [btrfs]()
>> > Modules linked in: ufs(E) qnx4(E) hfsplus(E) hfs(E) minix(E) ntfs(E) msdos(E) jfs(E) xfs(E) libcrc32c(E) btrfs(E) xor(E) raid6_pq(E) iosf_mbi(E) dm_crypt(E) kvm_intel(E) kvm(E) crct10dif_pclmul(E) crc32_pclmul(E) ppdev(E) ghash_clmulni_intel(E) aesni_intel(E) aes_x86_64(E) lrw(E) gf128mul(E) glue_helper(E) ablk_helper(E) cryptd(E) 8250_fintek(E) serio_raw(E) virtio_rng(E) parport_pc(E) mac_hid(E) pvpanic(E) i2c_piix4(E) lp(E) parport(E) cirrus(E) syscopyarea(E) sysfillrect(E) sysimgblt(E) ttm(E) mpt2sas(E) drm_kms_helper(E) raid_class(E) floppy(E) psmouse(E) drm(E) scsi_transport_sas(E)
>> > CPU: 7 PID: 3159 Comm: btrfs-transacti Tainted: G        W   E  3.19.0-031900-generic #201502091451
>> > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
>> > 00000000000001b6 ffff8801cb687c48 ffffffff817c4c00 0000000000000007
>> > 0000000000000000 ffff8801cb687c88 ffffffff81076e87 0000000000000001
>> > ffff8801fe80bf00 0000000000000000 ffff8801fe80bfc8 ffff8802345d8280
>> > Call Trace:
>> > [<ffffffff817c4c00>] dump_stack+0x45/0x57
>> > [<ffffffff81076e87>] warn_slowpath_common+0x97/0xe0
>> > [<ffffffff81076eea>] warn_slowpath_null+0x1a/0x20
>> > [<ffffffffc06b2d40>] btrfs_select_ref_head+0x120/0x130 [btrfs]
>> > [<ffffffffc0652cd1>] __btrfs_run_delayed_refs+0x1e1/0x5f0 [btrfs]
>> > [<ffffffffc0654ffa>] btrfs_run_delayed_refs.part.82+0x6a/0x290 [btrfs]
>> > [<ffffffffc0664e5c>] ? join_transaction.isra.31+0x13c/0x380 [btrfs]
>> > [<ffffffffc0655237>] btrfs_run_delayed_refs+0x17/0x20 [btrfs]
>> > [<ffffffffc0665e50>] btrfs_commit_transaction+0xb0/0xa70 [btrfs]
>> > [<ffffffffc0663d95>] transaction_kthread+0x1d5/0x250 [btrfs]
>> > [<ffffffffc0663bc0>] ? open_ctree+0x1f40/0x1f40 [btrfs]
>> > [<ffffffff81095d59>] kthread+0xc9/0xe0
>> > [<ffffffff81095c90>] ? flush_kthread_worker+0x90/0x90
>> > [<ffffffff817d1e7c>] ret_from_fork+0x7c/0xb0
>> > [<ffffffff81095c90>] ? flush_kthread_worker+0x90/0x90
>> > ---[ end trace dd65465954546463 ]---
>> > BTRFS warning (device dm-5): Skipping commit of aborted transaction.
>> > BTRFS: error (device dm-5) in cleanup_transaction:1670: errno=-5 IO failure
>>
>>
>> Any thoughts? Would it help to unplug the "dm5"-device which seems to
>> be causing this errors and then balance the array?
>>
>> Regards,
>> Tobias
>>
>> 2015-02-09 23:45 GMT+01:00 Tobias Holst <tobby@tobby.eu>:
>> > Hi
>> >
>> > I'm having some trouble with my six-drives btrfs raid6 (each drive
>> > encrypted with LUKS). At first: Yes, I do have backups, but it may
>> > take at least days, maybe weeks or even some month to restore
>> > everything from the (offside) backups. So it is not essential to
>> > recover the data, but would be great ;-)
>> >
>> > OS: Ubuntu 14.04
>> > Kernel: 3.19.0
>> > btrfs-progs: 3.19-rc2
>> >
>> > When booting my server I am getting this in the syslog:
>> >> [    8.026362] BTRFS: device label tobby-btrfs devid 3 transid 108721 /dev/dm-0
>> >> [    8.118896] BTRFS: device label tobby-btrfs devid 6 transid 108721 /dev/dm-1
>> >> [    8.202477] BTRFS: device label tobby-btrfs devid 1 transid 108721 /dev/dm-2
>> >> [    8.520988] BTRFS: device label tobby-btrfs devid 4 transid 108721 /dev/dm-3
>> >> [    8.555570] BTRFS info (device dm-3): force lzo compression
>> >> [    8.555574] BTRFS info (device dm-3): disk space caching is enabled
>> >> [    8.556310] BTRFS: failed to read the system array on dm-3
>> >> [    8.592135] BTRFS: open_ctree failed
>> >> [    9.039187] BTRFS: device label tobby-btrfs devid 2 transid 108721 /dev/dm-4
>> >> [    9.107779] BTRFS: device label tobby-btrfs devid 5 transid 108721 /dev/dm-5
>> > Looks like there is something wrong on drive 3, giving me "open_ctree
>> > failed". I have to press "S" to skip mounting of the btrfs volume. It
>> > boots and with "sudo mount --all" I can successfully mount the btrfs
>> > volume. Sometimes it takes one or two minutes but it will mount.
>> >
>> > After a while I am sometimes/randomly getting this in the syslog:
>> >> [ 1161.283246] BTRFS: dm-5 checksum verify failed on 39099619901440 wanted BB5B0AD5 found 6B6F5040 level 0
>> > Looks like something else is broken on dm-5... But shouldn't this be
>> > repaired with the new raid56-repair-features of kernel 3.19?
>> >
>> > After some more time I am getting this:
>> >> [637017.631044] BTRFS (device dm-4): parent transid verify failed on 39099305132032 wanted 108722 found 108719
>> > Then it is not possible to access the mounted volume anymore. I have
>> > to "umount -l" to unmount it and then I can remount it. Until it
>> > happens again (after some time)...
>> >
>> > I also tried a balance and a scrub but they "crash". Syslog is full of
>> > messages like the following examples:
>> >> [ 3355.523157] csum_tree_block: 53 callbacks suppressed
>> >> [ 3355.523160] BTRFS: dm-5 checksum verify failed on 39099306917888 wanted F90D8231 found 5981C697 level 0
>> >> [ 4006.935632]  BTRFS (device dm-5): parent transid verify failed on 30525418536960 wanted 108975 found 108767
>> > and "btrfs scrub status /[device]" gives me the following output:
>> >> "scrub status for [UUID]
>> >>        scrub started at Mon Feb  9 18:16:38 2015 and was aborted after 2008 seconds
>> >>        total bytes scrubbed: 113.04GiB with 0 errors"
>> >
>> > So a short summary:
>> > - btrfs raid6 on 3.19.0 with btrfs-progs 3.19-rc2
>> > - does not mount at boot up, "open_ctree failed" (disk 3)
>> > - mounts successfully after bootup
>> > - randomly "checksum verify failed" (disk 5)
>> > - balance and scrub crash after some time
>> > - after a while the volume gets unreadable, saying "parent transid
>> > verify failed" (disk 4 or 5)
>> >
>> > And it looks like there still is no way to btrfsck a raid6.
>> >
>> > Any ideas how to repair this filesystem?
>> >
>> > Regards,
>> > Tobias
>> --
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