On Thu, Sep 09, 2010 at 09:24:26AM +0300, Avi Kivity wrote: > The other thing we can do is defragment the logical image, then > defragment the underlying file (if the filesystem supports it, issue the > appropriate ioctl, otherwise defragment to a new file which you write > linearly).
What's what the defragmentation code does in a slightly optimized fashion anyway - so if you want to do it from qemu just do it that way. Don't even bother calling the filesystem ioctls directly given that they just implementa low-level helpers and the actual logic is in the userspace side of the defragmentation tools.
