Re: [PATCH] btrfs-progs: Skip device tree when we failed to read it

[Christian Wimmer <telefonchris@icloud.com>]

Sorry for the repeated post, I am trying to pass the mail server...

Hi Qui, 

I tried what you said and I got at least some very small files out of the device!

Yes, I have sub volumes/snapshots.

There should be a subvolume called “projects” which I am interested in.
Inside this subvolume should be lots of snapshots.

Any chance to recover one of them?

Here the output of the restore command that you suggested:

# ./btrfs restore -l /dev/sdb1 
checksum verify failed on 5349895454720 found 000000A8 wanted 00000000
checksum verify failed on 5349895454720 found 000000A8 wanted 00000000
checksum verify failed on 5349895454720 found 000000A8 wanted 00000000
bad tree block 5349895454720, bytenr mismatch, want=5349895454720, have=14275350892879035392
WARNING: could not setup device tree, skipping it
 tree key (EXTENT_TREE ROOT_ITEM 0) 641515520 level 2
 tree key (DEV_TREE ROOT_ITEM 0) 5349895454720 level 1
 tree key (FS_TREE ROOT_ITEM 0) 653901824 level 1
 tree key (CSUM_TREE ROOT_ITEM 0) 658161664 level 3
 tree key (UUID_TREE ROOT_ITEM 0) 657014784 level 0
 tree key (315 ROOT_ITEM 0) 637386752 level 1
checksum verify failed on 3542131507200 found 0000008C wanted 00000000
checksum verify failed on 3542131507200 found 000000F5 wanted 00000000
checksum verify failed on 3542131507200 found 0000008C wanted 00000000
bad tree block 3542131507200, bytenr mismatch, want=3542131507200, have=14275350892879035392

And I tried:

# ./btrfs restore -r 315 -v -D /dev/sdb1 test/
checksum verify failed on 5349895454720 found 000000A8 wanted 00000000
checksum verify failed on 5349895454720 found 000000A8 wanted 00000000
checksum verify failed on 5349895454720 found 000000A8 wanted 00000000
bad tree block 5349895454720, bytenr mismatch, want=5349895454720, have=14275350892879035392
WARNING: could not setup device tree, skipping it
This is a dry-run, no files are going to be restored
Restoring test/1
Skipping snapshot snapshot
Skipping existing file test/1/info.xml
If you wish to overwrite use -o
Done searching /1
Restoring test/4
Skipping snapshot snapshot
Skipping existing file test/4/info.xml
Done searching /4
Restoring test/28
Skipping snapshot snapshot
Skipping existing file test/28/info.xml
Done searching /28
Restoring test/52
checksum verify failed on 3305202188288 found 0000009E wanted FFFFFFA9
checksum verify failed on 3305202188288 found 000000FA wanted 00000000
checksum verify failed on 3305202188288 found 0000009E wanted FFFFFFA9
bad tree block 3305202188288, bytenr mismatch, want=3305202188288, have=18446556327804403584
Error reading subvolume test/52/snapshot: 18446744073709551611
Error searching test/52/snapshot


Well, I got the very small files info.xml.
How can I get the rest? Any ideas?

Thanks a lot for your help,



Chris