Pull btrfs fixes from David Sterba:

 - two regression fixes in clone/dedupe ioctls, the generic check
   callback needs to lock extents properly and wait for io to avoid
   problems with writeback and relocation

 - fix deadlock when using free space tree due to block group creation

 - a recently added check refuses a valid fileystem with seeding device,
   make that work again with a quickfix, proper solution needs more
   intrusive changes

* tag 'for-5.0-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: Use real device structure to verify dev extent
  Btrfs: fix deadlock when using free space tree due to block group creation
  Btrfs: fix race between reflink/dedupe and relocation
  Btrfs: fix race between cloning range ending at eof and writeback