* kwolf/for-anthony:
AHCI: Masking of IRQs actually masks them
sheepdog: fix co_recv coroutine context
AHCI: Fix port reset race
rewrite QEMU_BUILD_BUG_ON
qcow2: Keep unknown header extension when rewriting header
qcow2: Update whole header at once
vpc: Round up image size during fixed image creation
vpc: Add support for Fixed Disk type
iSCSI: add configuration variables for iSCSI
qemu-io: add write -z option for bdrv_co_write_zeroes
qed: add .bdrv_co_write_zeroes() support
qed: replace is_write with flags field
block: perform zero-detection during copy-on-read
block: add .bdrv_co_write_zeroes() interface
cutils: extract buffer_is_zero() from qemu-img.c
65b31cc207