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

Block layer patches

# gpg: Signature made Fri 06 Oct 2017 16:52:59 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: (54 commits)
  block/mirror: check backing in bdrv_mirror_top_flush
  qcow2: truncate the tail of the image file after shrinking the image
  qcow2: fix return error code in qcow2_truncate()
  iotests: Fix 195 if IMGFMT is part of TEST_DIR
  block/mirror: check backing in bdrv_mirror_top_refresh_filename
  block: support passthrough of BDRV_REQ_FUA in crypto driver
  block: convert qcrypto_block_encrypt|decrypt to take bytes offset
  block: convert crypto driver to bdrv_co_preadv|pwritev
  block: fix data type casting for crypto payload offset
  crypto: expose encryption sector size in APIs
  block: use 1 MB bounce buffers for crypto instead of 16KB
  iotests: Add test 197 for covering copy-on-read
  block: Perform copy-on-read in loop
  block: Add blkdebug hook for copy-on-read
  iotests: Restore stty settings on completion
  block: Uniform handling of 0-length bdrv_get_block_status()
  qemu-io: Add -C for opening with copy-on-read
  commit: Remove overlay_bs
  qemu-iotests: Test commit block job where top has two parents
  qemu-iotests: Allow QMP pretty printing in common.qemu
  ...

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