K 10 svn:author V 3 mav K 8 svn:date V 27 2017-03-17T11:45:16.009981Z K 7 svn:log V 387 MFC r309856: Postpone ZVOL media/block size caching till first open. At least on FreeBSD there are no legal way to access media or get its size without opening device/provider first. Postponing this caching allows to skip several disk seeks per ZVOL/snapshot during import. For HDD pool with 1 ZVOL in dev mode with 1000 snapshots this reduces pool import time from 40 to 10 seconds. END