Re: Corrupted FS with "open_ctree failed" and "failed to recover balance: -5"

[Udo Waechter <root@zoide.net>]

[-- Attachment #1.1: Type: text/plain, Size: 2593 bytes --]

Hello,

noone any ideas? Do you need more information?

Cheers,
udo.

On 11/07/18 17:37, Udo Waechter wrote:
> Hello everyone,
> 
> I have a corrupted filesystem which I can't seem to recover.
> 
> The machine is:
> Debian Linux, kernel 4.9 and btrfs-progs v4.13.3
> 
> I have a HDD RAID5 with LVM and the volume in question is a LVM volume.
> On top of that I had a RAID1 SSD cache with lvm-cache.
> 
> Yesterday both! SSDs died within minutes. This lead to the corruped
> filesystem that I have now.
> 
> I hope I followed the procedure correctly.
> 
> What I tried so far:
> * "mount -o usebackuproot,ro " and "nospace_cache" "clear_cache" and all
> permutations of these mount options
> 
> I'm getting:
> 
> [96926.830400] BTRFS info (device dm-2): trying to use backup root at
> mount time
> [96926.830406] BTRFS info (device dm-2): disk space caching is enabled
> [96926.927978] BTRFS error (device dm-2): parent transid verify failed
> on 321269628928 wanted 3276017 found 3275985
> [96926.938619] BTRFS error (device dm-2): parent transid verify failed
> on 321269628928 wanted 3276017 found 3275985
> [96926.940705] BTRFS error (device dm-2): failed to recover balance: -5
> [96926.985801] BTRFS error (device dm-2): open_ctree failed
> 
> The weird thing is that I can't really find information about the
> "failed to recover balance: -5" error. - There was no rebalancing
> running when during the crash.
> 
> * btrfs-find-root: https://pastebin.com/qkjnSUF7 - It bothers me that I
> don't see any "good generations" as described here:
> https://btrfs.wiki.kernel.org/index.php/Restore
> 
> * "btrfs rescue" - it starts, then goes to "looping on XYZ" then stops
> 
> * "btrfs rescue super-recover -v" gives:
> 
> All Devices:
> 	Device: id = 1, name = /dev/vg00/...
> Before Recovering:
> 	[All good supers]:
> 		device name = /dev/vg00/...
> 		superblock bytenr = 65536
> 
> 		device name = /dev/vg00/...
> 		superblock bytenr = 67108864
> 
> 		device name = /dev/vg00/...
> 		superblock bytenr = 274877906944
> 
> 	[All bad supers]:
> 
> All supers are valid, no need to recover
> 
> 
> * Unfortunatly I did a "btrfs rescue zero-log" at some point :( - As it
> turns out that might have been a bad idea
> 
> 
> * Also, a "btrfs  check --init-extent-tree" - https://pastebin.com/jATDCFZy
> 
> The volume contained qcow2 images for VMs. I need only one of those,
> since one piece of important software decided to not do backups :(
> 
> Any help is highly appreciated.
> 
> Many thanks,
> udo.
> 


[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 488 bytes --]