Re: read block failed check_tree_block / Couldn't read chunk tree

Qu Wenruo Sun, 26 Oct 2014 19:28:23 -0700


-------- Original Message --------
Subject: read block failed check_tree_block / Couldn't read chunk tree
From: Rene Thomas <re.tho...@gmx.de>
To: <linux-btrfs@vger.kernel.org>
Date: 2014年10月25日 00:43

Dear Developers / Maintainer,
I’ve set up a running RAID5 with three devices (sda1 / sdb1 /sdc1)


Mountpoint was /home, filesystem was mounted
A chain of unfortunal circumstances gives me the chance to run as root
in a terminal.

mkfs.ntfs /dev/sdb1

where /dev/sdb1 is device 1 in the Array.

After a while I’ve realised that the terminal I used was the wrong one
and killed the process where the progress still was 0%.
The filesystem was still in a readable state switched to read only.
Write access was not able.

After a restart the RAID failed to mount.

Tried several steps to reactivate the Array.

All btrfs commands leads to:

Check tree block failed, want=5845480062976, have=0
Check tree block failed, want=5845480062976, have=0
Check tree block failed, want=5845480062976, have=65536
Check tree block failed, want=5845480062976, have=0
Check tree block failed, want=5845480062976, have=0
read block failed check_tree_block
Couldn't read chunk tree

Chunk tree corruption will always lead to disaster :(

What about remove sdb1 and mount sda1/sdc1 with -o degraded ?
I hope the sda1/sdc1 is still in correct status...


Started with:
btrfs fi show
mount -o revovery,ro /dev/sdc1 /home
failed with error (see dmesg log at [311])
btrfs-image -c 9 -t 8 /dev/sdb1 /media/storageplace/fs_image
btrfs-zero-log /dev/sdb1
btrfs check /dev/sdb1
btrfs check --repair /dev/sdb1

At least I tried
btrfs rescue chunk-recover /dev/sdb1

Works for several hours on the arry and end up in (huge log available > 100k):

“Fail to recover the chunk tree.”

If my previous defraded doesn't help, chunk-recover is the last chancefor it.

If still failed, the chance to recover seems quite low.

However, can you upload the huge log for developers to investigate andimprove the chunk-recover tools?


Thanks,
Qu


  I’ve checked the super block there are no errors

My question is there any chance on a broken c tree to get the data
back? Not necessarily fix the Array only get the data.

Thanks in advanced

# uname -a
Linux engelserver 3.17.0-031700rc5-generic #201409151105 SMP Mon Sep
15 15:08:10 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux

  # btrfs --version
Btrfs v3.17

  # btrfs fi show
Label: 'mythstorage'  uuid: 9b454272-6800-4b3c-b196-9e180407a6cb
         Total devices 1 FS bytes used 2.36MiB
         devid    1 size 931.51GiB used 10.04GiB path /dev/sdd1

  Check tree block failed, want=5845480062976, have=0
Check tree block failed, want=5845480062976, have=0
Check tree block failed, want=5845480062976, have=65536
Check tree block failed, want=5845480062976, have=0
Check tree block failed, want=5845480062976, have=0
read block failed check_tree_block
Couldn't read chunk tree

Label: none  uuid: 8ef575d9-2465-479c-bf9c-067e2e417770
         Total devices 3 FS bytes used 3.02TiB
         devid    1 size 2.73TiB used 1.77TiB path /dev/sdb1
         devid    2 size 2.73TiB used 1.77TiB path /dev/sda1
         devid    3 size 2.73TiB used 1.77TiB path /dev/sdc1
Btrfs v3.17

dmesg:
[  280.637338] init: plymouth-upstart-bridge main process ended, respawning
[  311.298682] BTRFS info (device sdc1): disk space caching is enabled
[  311.335674] BTRFS: bad tree block start 0 5845480062976
[  311.336215] BTRFS: bad tree block start 0 5845480062976
[  311.354660] BTRFS: bad tree block start 0 5845480054784
[  311.354762] BTRFS: bad tree block start 0 5845480054784
[  311.355024] BTRFS: bad tree block start 0 5845480067072
[  311.355145] BTRFS: bad tree block start 0 5845480067072
[  311.355496] BTRFS: bad tree block start 0 5845480050688
[  311.355612] BTRFS: bad tree block start 0 5845480050688
[  311.356347] BTRFS: bad tree block start 0 5845480071168
[  311.356458] BTRFS: bad tree block start 0 5845480071168
[  311.580203] BTRFS: Failed to read block groups: -5
[  311.605073] BTRFS: open_ctree failed

René
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Re: read block failed check_tree_block / Couldn't read chunk tree

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