tree cf39358b64bb3eb0d227db2b753d163f8012797a
parent 3efffc3292d94271a15b1606b4a56adf6c6f04ed
author Max Reitz <mreitz@redhat.com> 1441990071 +0200
committer Kevin Wolf <kwolf@redhat.com> 1442242297 +0200

qcow2: Make qcow2_alloc_bytes() more explicit

In case of -EAGAIN returned by update_refcount(), we should discard the
cluster offset we were trying to allocate and request a new one, because
in theory that old offset might now be taken by a refcount block.

In practice, this was not the case due to update_refcount() generally
returning strictly monotonic increasing cluster offsets. However, this
behavior is not set in stone, and it is also not obvious when looking at
qcow2_alloc_bytes() alone, so we should not rely on it.

Reported-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>