Corrupted filesystem, best strategy to get back my data?

Corrupted filesystem, best strategy to get back my data?

[Sébastien Luttringer]

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Hello,

I have a new corruption on another Arch Linux server with a simple root btrfs
filesystem on an SSD.
The SSD has no corruption. Looks like the server crashed and rebooted. But the
next reboot failed because there is error with filesytem check.

Here is some info about the FS:

# btrfs fi sh
Label: 'white.root'  uuid: 617dda69-ffea-4569-9399-c6892e66d83a
Total devices 1 FS bytes used 24.33GiB
devid    1 size 468.44GiB used 50.03GiB path /dev/sdh2

# btrfs fi us root
Overall:
    Device size:	 468.44GiB
    Device allocated:	  50.03GiB
    Device unallocated:	 418.41GiB
    Device missing:	     0.00B
    Used:	  24.33GiB
    Free (estimated):	 443.10GiB	(min: 443.10GiB)
    Data ratio:	      1.00
    Metadata ratio:	      1.00
    Global reserve:	  66.17MiB	(used: 0.00B)

Data,single: Size:48.00GiB, Used:23.31GiB
   /dev/sdh2	  48.00GiB

Metadata,single: Size:2.00GiB, Used:1.02GiB
   /dev/sdh2	   2.00GiB

System,single: Size:32.00MiB, Used:16.00KiB
   /dev/sdh2	  32.00MiB

Unallocated:
   /dev/sdh2	 418.41GiB

Here is the output of check:

# btrfs check /dev/sdh2
Opening filesystem to check...
Checking filesystem on /dev/sdh2
UUID: 617dda69-ffea-4569-9399-c6892e66d83a
[1/7] checking root items
parent transid verify failed on 343358210048 wanted 3064554 found 3060713
parent transid verify failed on 343358210048 wanted 3064554 found 3060713
Ignoring transid failure
parent transid verify failed on 343358226432 wanted 3064554 found 3060713
parent transid verify failed on 343358226432 wanted 3064554 found 3060713
Ignoring transid failure
parent transid verify failed on 343358341120 wanted 3064554 found 3060713
parent transid verify failed on 343358341120 wanted 3064554 found 3060713
Ignoring transid failure
parent transid verify failed on 343358308352 wanted 3064554 found 3060713
parent transid verify failed on 343358308352 wanted 3064554 found 3060713
Ignoring transid failure
parent transid verify failed on 343358357504 wanted 3064554 found 3060713
parent transid verify failed on 343358357504 wanted 3064554 found 3060713
Ignoring transid failure
parent transid verify failed on 343358324736 wanted 3064554 found 3060713
parent transid verify failed on 343358324736 wanted 3064554 found 3060713
Ignoring transid failure
checksum verify failed on 343355752448 found 9ACEB5DF wanted E062A401
checksum verify failed on 343355752448 found 9ACEB5DF wanted E062A401
Csum didn't match
ERROR: failed to repair root items: Input/output error

I can readonly mount the filesystem manually with a livecd.
I got this:

[  100.074774] BTRFS info (device sdh2): disk space caching is enabled
[  100.076621] BTRFS info (device sdh2): bdev /dev/sdh2 errs: wr 5, rd 0, flush
0, corrupt 1536, gen 0
[  100.087027] BTRFS info (device sdh2): enabling ssd optimizations

After runing a find I got these too

[  102.175348] BTRFS warning (device sdh2): sdh2 checksum verify failed on
343356260352 wanted D4568D65 found EB1AC7D4 level 0
[  102.175505] BTRFS warning (device sdh2): sdh2 checksum verify failed on
343356260352 wanted D4568D65 found EB1AC7D4 level 0
[  102.176222] BTRFS warning (device sdh2): sdh2 checksum verify failed on
343356342272 wanted D62720B8 found A25C27B4 level 0
[  102.176367] BTRFS warning (device sdh2): sdh2 checksum verify failed on
343356342272 wanted D62720B8 found A25C27B4 level 0
[  102.176557] BTRFS warning (device sdh2): sdh2 checksum verify failed on
343356440576 wanted 5038C46D found 1E960B6E level 0
[  102.176701] BTRFS warning (device sdh2): sdh2 checksum verify failed on
343356440576 wanted 5038C46D found 1E960B6E level 0
[  102.176917] BTRFS error (device sdh2): parent transid verify failed on
343357227008 wanted 3064554 found 3060713
[  102.177140] BTRFS error (device sdh2): parent transid verify failed on
343357227008 wanted 3064554 found 3060713
[  102.177407] BTRFS error (device sdh2): parent transid verify failed on
343357358080 wanted 3064554 found 3060713
[  102.177633] BTRFS error (device sdh2): parent transid verify failed on
343357358080 wanted 3064554 found 3060713
[  102.177856] BTRFS warning (device sdh2): sdh2 checksum verify failed on
343357374464 wanted 86A838FF found 4C316BC7 level 0
[  102.178000] BTRFS warning (device sdh2): sdh2 checksum verify failed on
343357374464 wanted 86A838FF found 4C316BC7 level 0
[  102.178214] BTRFS error (device sdh2): parent transid verify failed on
343357456384 wanted 3064554 found 3060713
[  102.178433] BTRFS error (device sdh2): parent transid verify failed on
343357456384 wanted 3064554 found 3060713
[  102.178695] BTRFS error (device sdh2): parent transid verify failed on
343357521920 wanted 3064554 found 3060713
[  102.178922] BTRFS error (device sdh2): parent transid verify failed on
343357521920 wanted 3064554 found 3060713
[  111.849676] BTRFS warning (device sdh2): sdh2 checksum verify failed on
343355834368 wanted 5E58C9A found DBF228EE level 0
[  111.849730] BTRFS warning (device sdh2): sdh2 checksum verify failed on
343355883520 wanted E1BB9C8F found 69F2A569 level 0
[  111.849732] BTRFS warning (device sdh2): sdh2 checksum verify failed on
343355899904 wanted D6DE6F6F found 46976008 level 0
[  111.849846] BTRFS warning (device sdh2): sdh2 checksum verify failed on
343355834368 wanted 5E58C9A found DBF228EE level 0
[  112.088981] BTRFS warning (device sdh2): sdh2 checksum verify failed on
343356194816 wanted 761BD0D0 found 5C8CC96C level 0
[  112.089128] BTRFS warning (device sdh2): sdh2 checksum verify failed on
343356194816 wanted 761BD0D0 found 5C8CC96C level 0
[  112.173042] BTRFS warning (device sdh2): sdh2 checksum verify failed on
343355998208 wanted 6AB69B4F found 9EA49163 level 0
[  112.173181] BTRFS warning (device sdh2): sdh2 checksum verify failed on
343355998208 wanted 6AB69B4F found 9EA49163 level 0
[  112.223272] BTRFS error (device sdh2): parent transid verify failed on
343357521920 wanted 3064554 found 3060713
[  112.223478] BTRFS error (device sdh2): parent transid verify failed on
343357521920 wanted 3064554 found 3060713

I tried to backup my data with rsync but I have a lot of csum errors.

What's the best strategy to retrieve my data as they are, even if they have
some wrong bits ?
I guess --init-csum-tree is a bad idea ?

Regards,

-- 
Sébastien "Seblu" Luttringer

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