[fedora-virt] guestfish, libguestfs, ext4 and bad perms on /dev/kvm

Robert P. J. Day rpjday at crashcourse.ca
Wed Apr 22 19:20:14 UTC 2009

  (apologies if you've already seen this, my SMTP was a little
confused this morning when i sent it initially.)

  yesterday, in my ongoing quest to turn my brain to yogurt, i was
playing with richard jones' guestfish and libguestfs, and tried to
mount the root filesystem from the disk image that's now sitting in my
home directory so i can get at it without needing root permissions.

$ guestfish
> <fs> add f1164.img
> <fs> run
... wait wait wait ...
> <fs> mount /dev/f1164guest/lv_root /
libguestfs: error: mount: /dev/f1164guest/lv_root on /: mount: unknown
  filesystem type 'ext4'

  i mentioned this off-line to richard, who said he was just getting a
newer version of the libguestfs packages together, so i just upgraded
to 1.0,6 and:

$ guestfish
> <fs> run
open /dev/kvm: Permission denied
Could not initialize KVM, will disable KVM support
qemu: loading initrd (0x13acad0 bytes) at 0x0000000016c43000
> <fs> pvs
> <fs> lvs
> <fs> mount /dev/f1164guest/lv_root /
> <fs> mounts
> <fs>

  in short, ext4 filesystem support now appears to work, but there's
still the issue (perhaps addressed earlier) that non-root users don't
have access to KVM support but, from the perspective of libguestfs,
does that really matter?

  anyway, ext4 support is in there so things are working, at least to
the extent that i've tested it.


p.s.  i could have sworn i didn't get that /dev/kvm perms error
yesterday. did something about that change since version 1.0.4?

$ ls -l /dev/kvm
crw-rw---- 1 root root 10, 232 2009-04-22 05:16 /dev/kvm

Robert P. J. Day                               Waterloo, Ontario, CANADA

        Linux Consulting, Training and Annoying Kernel Pedantry.

Web page:                                          http://crashcourse.ca
Linked In:                             http://www.linkedin.com/in/rpjday
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