Re: btrfs send and receive showing errors

[Filipe Manana <fdmanana@kernel.org>]

On Wed, Jan 4, 2023 at 1:05 PM Randy Nürnberger <ranuberger@posteo.de> wrote:
>
> Hello,
>
> I’m in the process of copying a btrfs filesystem (a couple years old)
> from one disk to another by using btrfs send and receive on all
> snapshots. The snapshots were created by a tool every hour on the hour
> as one backup measure and automatically removed as they became older.
>
> I got errors like the following and when I compare the copied snapshots
> with the originals, some files are missing:
>
> ERROR: unlink █████ failed: No such file or directory
> ERROR: link █████ -> █████ failed: No such file or directory
> ERROR: utimes █████ failed: No such file or directory
> ERROR: rmdir █████ failed: No such file or directory
>
> Is this a known bug and how can I help diagnosing and fixing this?

So this is a problem caused by the sender issuing commands with outdated paths.

First, try doing the send operation again with a 6.1 kernel - there
was at least one fix here that may be relevant.

To actual debug things, in case it's not working with 6.1:

1) Show how you invoked send and receive. I.e. the full command lines
for 'btrfs send ...' and 'btrfs receive ...'

2) Provide the whole output of 'btrfs receive' with the -vvv command
line option.
    This will reveal all path names, but it's necessary to debug things.
    You've hidden path names above, so I suppose that's not acceptable for you.

Thanks.

>
>
> # uname -a  # this is the kernel on which this originally happend
> Linux arktos 5.10.0-20-amd64 #1 SMP Debian 5.10.158-2 (2022-12-13)
> x86_64 GNU/Linux
>
>
> # uname -a  # I already retried everything on the latest Debian
> backports kernel with the same results
> Linux arktos 6.0.0-0.deb11.6-amd64 #1 SMP PREEMPT_DYNAMIC Debian
> 6.0.12-1~bpo11+1 (2022-12-19) x86_64 GNU/Linux
>
> # btrfs --version
> btrfs-progs v5.10.1
>
> # btrfs fi sh /mnt/randy  # this is the source
> Label: none  uuid: 84bba855-578d-48db-80eb-49f1029c7543
>          Total devices 2 FS bytes used 2.04TiB
>          devid    1 size 4.00TiB used 2.05TiB path /dev/mapper/randy_1_crypt
>          devid    2 size 4.00TiB used 2.05TiB path /dev/mapper/randy_2_crypt
>
> # btrfs fi df /mnt/randy
> Data, RAID1: total=2.02TiB, used=2.02TiB
> System, RAID1: total=8.00MiB, used=320.00KiB
> Metadata, RAID1: total=25.00GiB, used=22.99GiB
> GlobalReserve, single: total=512.00MiB, used=0.00B
>
>
> # btrfs fi sh /mnt/intern  # this is the target
> Label: none  uuid: ebb94498-644c-42cd-892f-37886173523c
>          Total devices 2 FS bytes used 1.91TiB
>          devid    1 size 8.00TiB used 1.91TiB path
> /dev/mapper/vg_arktos_hdd_b-lv_randy_1
>          devid    2 size 8.00TiB used 1.91TiB path
> /dev/mapper/vg_arktos_hdd_b-lv_randy_2
>
> # btrfs fi df /mnt/intern
> Data, RAID1: total=1.89TiB, used=1.89TiB
> System, RAID1: total=8.00MiB, used=288.00KiB
> Metadata, RAID1: total=21.00GiB, used=20.76GiB
> GlobalReserve, single: total=512.00MiB, used=0.00B