Push ftruncate operations down through the diskmgr into the i/o pool.
Fixes a problem with conflict detection in the case of multiple resize operations being queued/active at the same time.
Merge branch 'next' into daniel_265
Merge branch 'next' into daniel_265
Changed resize conflict-resolution logic. I think it's more robust now.
Wrote unit tests for resizing conflict resolution.
Fix oversights after refactoring.
Merge branch 'next' into daniel_265
Make i/o account destruction wait for all requests to finish.
Stylistic fixes and such.
Very minor stylistic thing
Revert accidential change.
Merge branch 'next' into daniel_265
Simplified resize unblock logic.
Un-added a static_cast.
Lazily construct auto_drainer_t in disk mgr accounts.