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

Block layer fixes for 2.9.0-rc1

# gpg: Signature made Mon 13 Mar 2017 11:53:16 GMT
# 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:
  commit: Implement .bdrv_refresh_filename
  mirror: Implement .bdrv_refresh_filename
  block: Refresh filename after changing backing file
  commit: Implement bdrv_commit_top.bdrv_co_get_block_status
  block: Request block status from *file for BDRV_BLOCK_RAW
  block: Remove check_new_perm from bdrv_replace_child()
  migration: Document handling of bdrv_is_allocated() errors
  vvfat: React to bdrv_is_allocated() errors
  backup: React to bdrv_is_allocated() errors
  block: Drop unmaintained 'archipelago' driver
  file-posix: Consider max_segments for BlockLimits.max_transfer
  backup: allow target without .bdrv_get_info

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