Merge remote-tracking branch 'kwolf/for-anthony' into staging
* kwolf/for-anthony:
qemu-iotests: skip 039 with ./check -nocache
block: add BLOCK_O_CHECK for qemu-img check
qcow2: mark image clean after repair succeeds
qed: mark image clean after repair succeeds
blockdev: flip default cache mode from writethrough to writeback
virtio-blk: disable write cache if not negotiated
virtio-blk: support VIRTIO_BLK_F_CONFIG_WCE
qemu-iotests: Save some sed processes
ahci: Fix sglist memleak in ahci_dma_rw_buf()
ahci: Fix ahci cdrom read corruptions for reads > 128k
virtio-blk: fix use-after-free while handling scsi commands