tree 5ef188dd5051d5bbbf3222ec7857bd4e2b36f0d4
parent c0a667112cf33968b425dfbb50594aba54ea850b
author Jason Evans <jasone@canonware.com> 1479244073 -0800
committer Jason Evans <jasone@canonware.com> 1479244113 -0800

Add extent serial numbers.

Add extent serial numbers and use them where appropriate as a sort key
that is higher priority than address, so that the allocation policy
prefers older extents.

This resolves #147.