* 'for-anthony' of git://repo.or.cz/qemu/kevin:
Add qcow2 documentation
hw/xen_disk: aio_inflight not released in handling ioreq when nr_segments==0
Improve error handling in do_snapshot_blkdev()
Fix ATA SMART and CHECK POWER MODE
Don't allow multiwrites against a block device without underlying medium
tools: Use real async.c instead of stubs
Add error message for loading snapshot without VM state
block/qcow: Don't ignore immediate read/write and other failures
block/vdi: Don't ignore immediate read/write failures