[Qemu-block] [PATCH for-2.9 0/3] Fix bdrv_is_allocated usage bugs

[Eric Blake]

bdrv_is_allocated() returns tri-state, not just bool, although
there were several callers using it as a bool.  Fix them to
either propagate the error or to document why treatment of
failure like allocation is okay.

[Found during a larger effort to convert bdrv_get_block_status
to be byte-based for 2.10]

Eric Blake (3):
  backup: React to bdrv_is_allocated() errors
  vvfat: React to bdrv_is_allocated() errors
  migration: Document handling of bdrv_is_allocated() errors

 block/backup.c    | 14 ++++++++++----
 block/vvfat.c     | 22 +++++++++++++++++++---
 migration/block.c |  2 ++
 3 files changed, 31 insertions(+), 7 deletions(-)

-- 
2.9.3