There are a number of tests that depend on "wait_delete_completed" in order to avoid running out of space when the filesystem is getting full. However, it would be better if the MDS(es) would more aggressively destroy OST objects to reclaim space when the OSTs are getting full.

The MDSes could potentially slow down object creation in this case to moderate new file creation to match the rate of object destroys, so that the free space is not totally consumed when there are still objects in the queue to be destroyed.