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

Block layer patches:

- qcow2: Use worker threads for compression to improve performance of
  'qemu-img convert -W' and compressed backup jobs
- blklogwrites: New filter driver to log write requests to an image in
  the dm-log-writes format
- file-posix: Fix image locking during image creation
- crypto: Fix memory leak in error path
- Error out instead of silently truncating node names

# gpg: Signature made Thu 05 Jul 2018 11:24:33 BST
# gpg:                using RSA key 7F09B272C88F2FD6
# gpg: Good signature from "Kevin Wolf <[email protected]>"
# Primary key fingerprint: DC3D EB15 9A9A F95D 3D74  56FE 7F09 B272 C88F 2FD6

* remotes/kevin/tags/for-upstream:
  file-posix: Unlock FD after creation
  file-posix: Fix creation locking
  block/blklogwrites: Add an option for the update interval of the log superblock
  block/blklogwrites: Add an option for appending to an old log
  block/blklogwrites: Change log_sector_size from int64_t to uint64_t
  block/crypto: Fix memory leak in create error path
  block: Don't silently truncate node names
  block: Add blklogwrites
  block: Move two block permission constants to the relevant enum
  qcow2: add compress threads
  qcow2: refactor data compression
  qemu-img: allow compressed not-in-order writes

Signed-off-by: Peter Maydell <[email protected]>