[systemd-devel] btrfs raid not ready but systemd tries to mount it anyway

[Daniel J. R. May]

On Fri, 2020-10-16 at 15:16 +0200, Lennart Poettering wrote:
> So the btrfs ready ioctl is called and the device considered by the
> kernel btrfs implementation  to be ready
> (i.e. assembled from all component devices) with this line:
> 
> [   27.804250] systemd-udevd[712]: sde: /usr/lib/udev/rules.d/64-btrfs.rules:15 RUN '/usr/bin/udevadm trigger -s block -p ID_BTRFS_READY=0'
> 
> (that's line 35792)
> 
> And srv.mount then later mounts the thing correctly.
> 
> Where's the problem supposed to be be?
> 
I will try and summarise the situation in one message to help make
things clear. Here is a summarised history of the problem:

1. The original problem: 
A 10 HDD BTRFS volume with 4 drives connected to the motherboard and 6
drives connected to the HBA *fails* to mount automatically at boot time.
The log for this (without any special debugging options set in grub) is
here:

https://drive.google.com/file/d/1o1-7smQAjg3LKP98EFfeHbb_jZdNz_jT/view?usp=sharing

2. Debugging with "rd.udev.debug systemd.log_level=debug":
The same 10 HDD BTRFS volume with 4 drives connected to the motherboard
and 6 drives connected to the HBA *fails* to mount automatically at boot
time. The log for this with "rd.udev.debug systemd.log_level=debug" set
in grub is here:

https://drive.google.com/file/d/1jVHjAQ8CY9vABtM2giPTB6XeZCclm7R-/view?usp=sharing


3. Debugging with "udev.log_priority=debug systemd.log_level=debug":
The same 10 HDD BTRFS volume with 4 drives connected to the motherboard
and 6 drives connected to the HBA *correctly* mounts automatically at
boot time. The log for this with "udev.log_priority=debug
systemd.log_level=debug" set in grub is here:

https://drive.google.com/file/d/1-x26JS5gcZxwZx7zWoKduEg9ycwUHKqO/view?usp=sharing

This was the one you were looking at which caused you to ask "Where's
the problem supposed to be be?" 😉

4. Changing HDD connections:
When I changed the hard drive connections so that all 10 HDDs are
connected via the HBA the BTRFS volume *correctly* mounts automatically
at boot time.


I hope that is a bit clearer.

So although putting all the HDDs on the HBA seems to fix the problem for
me. I thought that I should report my findings.

Thank you for all your time and effort looking into this.

Best wishes,

Dan


-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 833 bytes
Desc: This is a digitally signed message part
URL: <https://lists.freedesktop.org/archives/systemd-devel/attachments/20201016/c7e250ac/attachment.sig>