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

[Chris Murphy]

Hi,

A Fedora 32 (systemd-245.8-2.fc32) user has a 10-drive Btrfs raid1 set
to mount in /etc/fstab:

UUID=f89f0a16-<snipped>  /srv   btrfs  defaults,nofail,x-systemd.requires=/  0 0

For some reason, systemd is trying to mount this file system before
all ten devices are ready. Supposedly this rule applies:
https://github.com/systemd/systemd/blob/master/rules.d/64-btrfs.rules.in

Fedora does have /usr/lib/udev/rules.d/64-btrfs.rules but I find no
reference at all to this rule when the user boots with 'rd.udev.debug
systemd.log_level=debug'. The entire journal is here:

https://drive.google.com/file/d/1jVHjAQ8CY9vABtM2giPTB6XeZCclm7R-/view

I expect a workaround would be to use mount option:

x-systemd.automount,noauto,nofail,x-systemd.requires=/

In fact, I'm not sure x-systemd.requires is needed because / must be
mounted successfully to read /etc/fstab in the first place; in order
to know to mount this file system at /srv

Anyway I'm mainly confused why the btrfs udev rule is seemingly not
applied in this case.

-- 
Chris Murphy