9439 ZFS double-free due to failure to dirty indirect block
illumos/illumos-gate@99a19144e82244f3426f055cc73af8a937c0135c
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Paul Dagnelie <pcd@delphix.com>
Approved by: Robert Mustacchi <rm@joyent.com>
Author: Matthew Ahrens <mahrens@delphix.com>