/**
* Find a bucket to allocate a block
*
* @return the offset in the IOEngine
*/
public long allocateBlock() {
Bucket b = null;
if (freeBuckets.size() > 0) // Use up an existing one first...
b = freeBuckets.get(freeBuckets.size() - 1);
if (b == null) {
b = grabGlobalCompletelyFreeBucket();
if (b != null) instantiateBucket(b);
}
if (b == null) return -1;
long result = b.allocate();
blockAllocated(b);
return result;
}
