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

Block layer patches

# gpg: Signature made Tue 03 Apr 2018 16:48:53 BST
# gpg:                using RSA key 7F09B272C88F2FD6
# 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:
  iotests: Test abnormally large size in compressed cluster descriptor
  qemu-iotests: Use ppc64 qemu_arch on ppc64le host
  iotests: Test preallocated truncate of 2G image
  block/file-posix: Fix fully preallocated truncate
  iotests: fix 208 for luks format
  iotests: Update 186 after commit ac64273c66ab136c44043259162
  iotests: Update 051 and 186 after commit 1454509726719e0933c
  block: handle invalid lseek returns gracefully
  gluster: Fix blockdev-add with server.N.type=unix

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