Re: [Libguestfs] [PATCH v2] daemon: Move lvmetad to early in the appliance boot process.

On Thursday, 24 May 2018 16:01:22 CEST Richard W.M. Jones wrote: > When the daemon starts up it creates a fresh (empty) LVM configuration > and starts up lvmetad (which depends on the LVM configuration). > > However this appears to cause problems: Some types of PV seem to > require lvmetad and don't work without it > (https://bugzilla.redhat.com/show_bug.cgi?id=1581810). If we don't > start lvmetad earlier, the device nodes are not created. > > Therefore move the whole initialization step into appliance/init. > > Two further changes had to be made: > > Now we are using lvmetad all the time, using vgchange is incorrect. > With lvmetad activated early we must use ‘pvscan --cache --activate ay’ > to scan all disks for PVs and activate any VGs on them (although the > documentation is complex, confusing and contradictory so I'm not > completely sure about this). > > The ‘lvm_system_dir’ local variable in ‘daemon/lvm-filter.c’ > previously contained the path of the directory above $LVM_SYSTEM_DIR > (eg. $LVM_SYSTEM_DIR = "/etc/lvm", lvm_system_dir = "/etc"). As this > was highly confusing, I have changed it so the local variable and the > environment variable have identical contents. This involved removing > the ‘lvm/’ component from a couple of paths since it is now included > in the local variable. > --- Mostly LGTM, but there is one thing to fix: > + lvm_system_dir = getenv ("LVM_SYSTEM_DIR"); > + if (!lvm_system_dir) > + lvm_system_dir = "/etc/lvm"; > + fprintf (stderr, "lvm_system_dir = %s\n", lvm_system_dir); The pointer returned by getenv() can change, so it will be better to duplicate its result, and store that instead for the daemon lifetime.