Re: btrfs send receive ERROR: chown failed: No such file or directory

[Leonard Lausen <leonard@lausen.nl>]

Hey Filipe,

thanks for the feedback. I ran the command again with -vv. Below are
the last commands logged by btrfs receive to stderr:

  mkfile o2138798-5016457-0
  rename leonard/mail/lists/emacs-orgmode/new/1530428589.M675528862P21583Q6R28ec1af3.leonard-xps13 -> o2138802-5207521-0
  rename o2138798-5016457-0 -> leonard/mail/lists/emacs-orgmode/new/1530428589.M675528862P21583Q6R28ec1af3.leonard-xps13
  utimes leonard/mail/lists/emacs-orgmode/new
  ERROR: cannot open /mnt/_btrbk_backups/leonard-xps13/@home.20180902T0045/o2138798-5016457-0: No such file or directory

The file which is mentioned above has in fact not changed between the
parent and current snapshot. I computed further a hash of the file on
source volume for parent and current snapshot and target on target
volume for parent snapshot. I get the same hash value in all 3 cases, so
the parent snapshot was apparently transferred correctly.

Note that the folder in which this file is placed contains 96558 files
whose sizes sum to 774M.

I further observed that the snapshot that previously failed to transfer
via send receive could now be sent / received without error. However,
the error then occured again for the next snapshot (which has the now
successfully transferred one as parent). There may be a race condition
that leads to non-deterministic failures.

Please let me know if I can help with any further information.

Best regards
Leonard

Filipe Manana <fdmanana@gmail.com> writes:

>> > 1) Machine 1 takes regular snapshots and sends them to machine 2. btrfs
>> >    btrfs send ... | ssh user@machine2 "btrfs receive /path1"
>> > 2) Machine 2 backups all subvolumes stored at /path1 to a second
>> >    independent btrfs filesystem. Let /path1/rootsnapshot be the first
>> >    snapshot stored at /path1 (ie. it has no Parent UUID). Let
>> >    /path1/incrementalsnapshot be a snapshot that has /path1/rootsnapshot
>> >    as a parent. Then
>> >    btrfs send -v /path1/rootsnapshot | btrfs receive /path2
>> >    works without issues, but
>> >    btrfs send -v -p /path1/rootsnapshot /path1/incrementalsnapshot | btrfs receive /path2
>
> -v is useless. Use -vv, which will dump all commands.
>
>> >    fails as follows:
>> >    ERROR: chown o257-4639416-0 failed: No such file or directory
>> >
>> > No error is shown in dmesg. /path1 and /path2 denote two independent
>> > btrfs filesystems.
>> >
>> > Note that there was no issue with transferring incrementalsnapshot from
>> > machine 1 to machine 2. No error is shown in dmesg.