Stefan Hajnoczi <stefa...@redhat.com> writes: > LVM volumes can be set read-only with "lvchange --permission r > <volume>". The device node permissions remain unchanged so the volume > can still be opened O_RDWR. Actual writes will fail.
Are you sure it's just LVM? blockdev(8) suggests it's a more general issue. Check out --setro there. > This results in odd behavior for QEMU. bdrv_open() is supposed to fail > if a read-only image is being opened with BDRV_O_RDWR. By not failing > for LVM volumes, the guest boots up but every write produces an I/O > error. > > This patch checks whether the block device is read-only so that LVM > volumes behave like regular files. > > Reported-by: Sibiao Luo <s...@redhat.com> > Suggested-by: Paolo Bonzini <pbonz...@redhat.com> > Signed-off-by: Stefan Hajnoczi <stefa...@redhat.com> Patch looks good to me.
