Recovering filesystems within qcow2

After recent crash of my laptop (hardware died) my QCOW2 images suffered minor damage and for the heck I couldn’t convince Fedora VM to auto-fsck itself so I had to go all manual after N-th prompt from dracut shell about problems starting up.

Turns out it’s not so complicated to get to the guts of the QCOW2 after all:

 #  modprobe nbd max_part=16
 #  qemu-nbd --connect=/dev/nbd0 /var/lib/libvirt/images/foo.qcow2
 #  fdisk -l /dev/nbd0
 #  pvscan
 #  vgchange -a y fedora
 #  fsck.ext4 -y /dev/fedora/rootfs 
 #  vgchange -a n fedora
 #  qemu-nbd --disconnect /dev/nbd0

In above snippet “fedora” is my VM’s VG name and rootfs was the offending LV

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