Merge remote-tracking branch 'remotes/kevin/tags/for-upstream' into staging

Block layer patches

# gpg: Signature made Thu 26 Oct 2017 14:02:54 BST
# gpg:                using RSA key 0x7F09B272C88F2FD6
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>"
# Primary key fingerprint: DC3D EB15 9A9A F95D 3D74  56FE 7F09 B272 C88F 2FD6

* remotes/kevin/tags/for-upstream: (35 commits)
  iotests: Add cluster_size=64k to 125
  qcow2: Always execute preallocate() in a coroutine
  qcow2: Fix unaligned preallocated truncation
  qcow2: Emit errp when truncating the image tail
  iotests: Filter actual image size in 184 and 191
  iotests: Pull _filter_actual_image_size from 67/87
  iotests: Add test for dataplane mirroring
  qcow2: Use BDRV_SECTOR_BITS instead of its literal value
  qemu-img.1: Image invalidation on qemu-img commit
  qemu-io: Relax 'alloc' now that block-status doesn't assert
  qcow2: Reduce is_zero() rounding
  block: Reduce bdrv_aligned_preadv() rounding
  block: Align block status requests
  qemu-img: Change img_compare() to be byte-based
  qemu-img: Change img_rebase() to be byte-based
  qemu-img: Change compare_sectors() to be byte-based
  qemu-img: Change check_empty_sectors() to byte-based
  qemu-img: Drop redundant error message in compare
  qemu-img: Add find_nonzero()
  qemu-img: Speed up compare on pre-allocated larger file
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>