I have a USB-HDD of 2TB size with metadata DUP . After an unclean
shutdown I now cannot mount it anymore.
My question is what (possibly destructive) rescue operation to try next
after having backuped the corrupted disk elsewhere first.
I am thinking of `btrfs check --init-extent-tree` or `btrfs rescue
chunk-recover`
Unfortunately I'm not well versed enough in btrfs to know what precisely
that would do, or if it would help at all or just make it worse.
I also don't know how to use that less corrupted DUPlicated version of
the FStree to get the disk to be mountable again, which, if I understand
it correctly, would open up scrub and balance as other possible repair
options.
Thanks in advance for your help and awesome filesystem.
Cheers!
Here's what I've done so far:
$ uname -a
Linux Fabian-openSUSE 5.11.12-1-default #1 SMP Wed Apr 7 17:30:21 UTC
2021 (92a542e) x86_64 x86_64 x86_64 GNU/Linux
$ sudo btrfs --version
[sudo] password for root:
btrfs-progs v5.11
$ sudo btrfs fi show
Label: 'BTRFS-Archive' uuid: 2566e7c1-1e0f-40eb-ab68-914e5c346884
Total devices 1 FS bytes used 1.60TiB
devid 1 size 1.82TiB used 1.61TiB path /dev/sdb2
dmesg outputs the following with `mount -o rescue=all,ro`
[23079.810710] BTRFS info (device sdb2): enabling all of the rescue options
[23079.810713] BTRFS info (device sdb2): ignoring data csums
[23079.810713] BTRFS info (device sdb2): ignoring bad roots
[23079.810715] BTRFS info (device sdb2): disabling log replay at mount time
[23079.810716] BTRFS info (device sdb2): disk space caching is enabled
[23079.810717] BTRFS info (device sdb2): has skinny extents
[23079.925185] BTRFS info (device sdb2): bdev /dev/sdb2 errs: wr 0, rd
0, flush 0, corrupt 51, gen 0
[23080.156357] BTRFS critical (device sdb2): corrupt leaf: root=1
block=449881636864 slot=18 ino=2276, invalid inode generation: has 13167
expect (0, 13165]
[23080.156377] BTRFS error (device sdb2): block=449881636864 read time
tree block corruption detected
[23080.169840] BTRFS critical (device sdb2): corrupt leaf: root=1
block=449881636864 slot=18 ino=2276, invalid inode generation: has 13167
expect (0, 13165]
[23080.169859] BTRFS error (device sdb2): block=449881636864 read time
tree block corruption detected
[23080.169891] BTRFS error (device sdb2): failed to read block groups: -5
[23080.173682] BTRFS error (device sdb2): open_ctree failed
$ sudo btrfs check /dev/sdb2
Opening filesystem to check...
parent transid verify failed on 449881636864 wanted 12615 found 13172
parent transid verify failed on 449881636864 wanted 12615 found 13172
parent transid verify failed on 449881636864 wanted 12615 found 13172
Ignoring transid failure
leaf parent key incorrect 449881636864
ERROR: failed to read block groups: Operation not permitted
ERROR: cannot open file system
I have already run `btrfs rescue super-recover` and `btrfs rescue
zero-log` without success.
Luckily I have set up that disk with metadata DUP so I was able to do
$ sudo btrfs check -r 30408704 -s1 -p /dev/sdb2
and
$ sudo btrfs restore -D -t 30408704 -i /dev/sdb2 1TB-Platte2/
After finding that (stripe 1) offset via
$ sudo btrfs inspect-internal dump-super -f /dev/sdb2
superblock: bytenr=65536, device=/dev/sdb2
---------------------------------------------------------
csum_type 0 (crc32c)
csum_size 4
csum 0x236347b4 [match]
bytenr 65536
flags 0x1
( WRITTEN )
magic _BHRfS_M [match]
fsid 2566e7c1-1e0f-40eb-ab68-914e5c346884
metadata_uuid 2566e7c1-1e0f-40eb-ab68-914e5c346884
label BTRFS-Archive
generation 13164
root 2271131025408
sys_array_size 129
chunk_root_generation 13160
root_level 1
chunk_root 22036480
chunk_root_level 1
log_root 0
log_root_transid 0
log_root_level 0
total_bytes 2000188080128
bytes_used 1759527608320
sectorsize 4096
nodesize 16384
leafsize (deprecated) 16384
stripesize 4096
root_dir 6
num_devices 1
compat_flags 0x0
compat_ro_flags 0x0
incompat_flags 0x179
( MIXED_BACKREF |
COMPRESS_LZO |
COMPRESS_ZSTD |
BIG_METADATA |
EXTENDED_IREF |
SKINNY_METADATA )
cache_generation 13164
uuid_tree_generation 13164
dev_item.uuid 5dda7f3a-edeb-45ed-8a94-d1c11bc74400
dev_item.fsid 2566e7c1-1e0f-40eb-ab68-914e5c346884 [match]
dev_item.type 0
dev_item.total_bytes 2000188080128
dev_item.bytes_used 1765256724480
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
sys_chunk_array[2048]:
item 0 key (FIRST_CHUNK_TREE CHUNK_ITEM 22020096)
length 8388608 owner 2 stripe_len 65536 type SYSTEM|DUP
io_align 65536 io_width 65536 sector_size 4096
num_stripes 2 sub_stripes 0
stripe 0 devid 1 offset 22020096
dev_uuid 5dda7f3a-edeb-45ed-8a94-d1c11bc74400
stripe 1 devid 1 offset 30408704
dev_uuid 5dda7f3a-edeb-45ed-8a94-d1c11bc74400
backup_roots[4]:
backup 0:
backup_tree_root: 2271131025408 gen: 13164
level: 1
backup_chunk_root: 22036480 gen: 13160
level: 1
backup_extent_root: 2271131041792 gen: 13164
level: 2
backup_fs_root: 2271132139520 gen: 13163
level: 2
backup_dev_root: 2271131910144 gen: 13164
level: 1
backup_csum_root: 2271144263680 gen: 13164
level: 2
backup_total_bytes: 2000188080128
backup_bytes_used: 1759527608320
backup_num_devices: 1
backup 1:
backup_tree_root: 2271522717696 gen: 13161
level: 1
backup_chunk_root: 22036480 gen: 13160
level: 1
backup_extent_root: 2271427756032 gen: 13161
level: 2
backup_fs_root: 2271659212800 gen: 13162
level: 2
backup_dev_root: 2271845613568 gen: 13160
level: 1
backup_csum_root: 2271115018240 gen: 13161
level: 2
backup_total_bytes: 2000188080128
backup_bytes_used: 1759125020672
backup_num_devices: 1
backup 2:
backup_tree_root: 2271131172864 gen: 13162
level: 1
backup_chunk_root: 22036480 gen: 13160
level: 1
backup_extent_root: 2271126110208 gen: 13162
level: 2
backup_fs_root: 2271659212800 gen: 13162
level: 2
backup_dev_root: 2271845613568 gen: 13160
level: 1
backup_csum_root: 2272123355136 gen: 13162
level: 2
backup_total_bytes: 2000188080128
backup_bytes_used: 1759290830848
backup_num_devices: 1
backup 3:
backup_tree_root: 2271143755776 gen: 13163
level: 1
backup_chunk_root: 22036480 gen: 13160
level: 1
backup_extent_root: 2271141412864 gen: 13163
level: 2
backup_fs_root: 2271132139520 gen: 13163
level: 2
backup_dev_root: 2271845613568 gen: 13160
level: 1
backup_csum_root: 2271132188672 gen: 13163
level: 2
backup_total_bytes: 2000188080128
backup_bytes_used: 1759527608320
backup_num_devices: 1
