Re: [Libguestfs] [PATCH nbdkit v3 4/4] Add linuxdisk plugin.

(Sorry for the abbreviated reply, rather spotty internet in this fishing village on the Noto peninsula :-) I added an extra commit which adds a common path for WIFEXITED and friends. We have something similar to it in libguestfs which we use all over. It also deals with WIFSTOPPED which I guess is not reachable in the places we use it now, but might become used in a future commit? (Actually I wonder if it's reachable if nbdkit is run under ptrace?) About writes to the disk: ‘-o ro’ will write to the journal if it needs recovery. We hit that bug in libguestfs many years back. I was also expecting to say here that ‘-o ro’ will write to a newly created filesystem to do lazy journal initialization and/or lazy inode table initialization (both features are enabled by default). However having said that I wasn't able to reproduce that behaviour in testing just now, even when I used type=ext4, so I guess this is suppressed by the kernel for r/o mounts. In any case it's definitely the case that you cannot mix even a single writable mount with other r/o mounts, for reasons which are obvious to us filesystem veterans, but which users tend to expect "should work". And I'd be leary about mixing even only ‘-o ro’ mounts because of journal recovery. (Of course it's safe if the disk itself is read-only). I also modified the busybox example using mkdir -p which, along with shell {} expansion, does indeed make the example a little shorter. Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com virt-top is 'top' for virtual machines. Tiny program with many powerful monitoring features, net stats, disk stats, logging, etc. http://people.redhat.com/~rjones/virt-top