Raid0 broken after one drive power outage with raid1 metadata

Raid0 broken after one drive power outage with raid1 metadata

[mcq909]

Hello,
I have a btrfs raid0 array (2 drives) with raid1 metadata that is broken after the power of one of the drives was
unplugged for a few seconds. The hardware and superblocks are fine but the chunk-root seems to be destroyed.
I had some success with btrfs rescue chunk-recover, after a long analysis (2x16TB) i get the message that a lot of chunks can be recovered:
"Total Chunks: 5761, Recoverable: 5449, Unrecoverable: 312".
After that a list of Orphan Device Extents is shown and then btrfs (version 5.15.1) crashes with:
"kernel-shared/volumes.c:1708: btrfs_rmap_block: BUG_ON `!ce` triggered, value 1".
Is there anything i can do to continue? I am so hopefull it is somehow possible to recover at least those 5449 chunks.
Many thanks for any suggestion!
M. Webber

Below is a summary of all rescue attempts so far (both drives, sdb and sdc, are online and fdisk readable):

System:
Linux 5.15.2
btrfs-progs v5.15.1


mount -o ro /dev/sdb /mnt
	BTRFS warning: checksum verify failed on 22036480 wanted 0x00000000 found 0x7b064cd2 level 1
	BTRFS error: failed to read chunk root
	BTRFS error: open_ctree failed
	mount: /mnt: wrong fs type, bad option, bad superblock on /dev/sdb, missing codepage or helper 	program, or other error


mount -o ro,rescue=usebackuproot /dev/sdb /mnt
	BTRFS warning: checksum verify failed on 22036480 wanted 0x00000000 found 0x7b064cd2 level 1
	BTRFS error: failed to read chunk root
	BTRFS error: open_ctree failed
	mount: /mnt: wrong fs type, bad option, bad superblock on /dev/sdb, missing codepage or helper 	program, or other error


btrfs rescue super-recover /dev/sdb
	All supers are valid, no need to recover


btrfs check /dev/sdb
	Opening filesystem to check...
	checksum verify failed on 22036480 wanted 0x00000000 found 0x7b064cd2
	Csum didn't match
	ERROR: cannot read chunk root
	ERROR: cannot open file system


btrfs restore /dev/sdb /tmp
	checksum verify failed on 22036480 wanted 0x00000000 found 0x7b064cd2
	Csum didn't match
	ERROR: cannot read chunk root
	Could not open root, trying backup super
	warning, device 1 is missing
	checksum verify failed on 22036480 wanted 0x00000000 found 0x7b064cd2
	Csum didn't match
	ERROR: cannot read chunk root
	Could not open root, trying backup super
	warning, device 1 is missing
	checksum verify failed on 22036480 wanted 0x00000000 found 0x7b064cd2
	Csum didn't match
	ERROR: cannot read chunk root
	Could not open root, trying backup super


btrfs rescue zero-log /dev/sdb
	checksum verify failed on 22036480 wanted 0x00000000 found 0x7b064cd2
	ERROR: cannot read chunk root
	ERROR: could not open ctree


btrfs rescue chunk-recover /dev/sdb
	runs for a long time and then crashes with BUG_ON(!ce) from volumes.c triggered,
	replacing BUG_ON(!ce) with if(!ce) return 0; does not help, core dumped


btrfs inspect-internal dump-super -f -a /dev/sdb
	generation              26935
	chunk_root_generation   26935
	root_level              1
	chunk_root              22036480
	chunk_root_level        1
	cache_generation        26934
	uuid_tree_generation    26934
	sys_chunk_array[2048]:
        item 0 key (FIRST_CHUNK_TREE CHUNK_ITEM 22020096)
	length 8388608 owner 2 stripe_len 65536 type SYSTEM|RAID1
        io_align 65536 io_width 65536 sector_size 4096
        num_stripes 2 sub_stripes 1
        stripe 0 devid 1 offset 22020096
        stripe 1 devid 2 offset 1048576

	backup_roots[4]:
        backup 0:
                backup_tree_root:       4811447648256   gen: 26933      level: 1
                backup_chunk_root:      22134784        gen: 26933      level: 1
                backup_extent_root:     4811320770560   gen: 26933      level: 2
        backup 1:
                backup_tree_root:       4811056234496   gen: 26934      level: 1
                backup_chunk_root:      22134784        gen: 26933      level: 1
                backup_extent_root:     4811055906816   gen: 26934      level: 2
        backup 2:
                backup_tree_root:       4811009376256   gen: 26935      level: 1
                backup_chunk_root:      22036480        gen: 26935      level: 1
                backup_extent_root:     4810999791616   gen: 26935      level: 2
        backup 3:
                backup_tree_root:       4811296555008   gen: 26932      level: 1
                backup_chunk_root:      22020096        gen: 26932      level: 1
                backup_extent_root:     4811259297792   gen: 26932      level: 2

For "btrfs check" it also does not matter if -s 0,1,2 or --chunk-root 22020096, 22036480 and so on is used.