[systemd-devel] [PATCH 1/2] fstab-generator: mount /usr in the initrd if specified on /proc/cmdline

Lennart Poettering lennart at poettering.net
Fri Mar 1 09:54:03 PST 2013

On Fri, 01.03.13 18:33, Harald Hoyer (harald.hoyer at gmail.com) wrote:

> Ok, what do we need for /usr?
> 1. if specified on the kernel command line, we don't need /sysroot/etc/fstab and
> can generate everything with the fstab-generator.
> 2. if not specified on the kernel command line, we have to wait for
> sysroot.mount and then copy over the /usr line to /etc/fstab and change the
> mountpoint to "/sysroot/usr". After that a daemon-reload would rerun the
> fstab-generator, which would generate the correct units.
> If /usr is a btrfs subvolumes of the root volume, then we have to use some of
> the rootflags for /usr also. E.g. it's not possible to mount root ro and /usr
> rw, IIRC.

I am tempted to say that we should only have one way and one way only to
do this. I.e. forget about the "usr=" idea on the kernel
cmdline. Instead, fstab-generator should just always look into
/etc/fstab and mount everything from there. When run from an initrd
environment it should also look into /sysroot/etc/fstab and mount
everything marked "x-initrd.mount" (plus, as a special implied magic,
/usr listed in there even if it lacks this new option). Of course, when
reading from /sysroot/etc/fstab the dest path of each mount should
always be prefixed with "/sysroot/".


Lennart Poettering - Red Hat, Inc.

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