When scn->scn_maxinflight_bytes has not been initialized it's
possible to hang on the condition variable in scan_exec_io().
This issue was uncovered by ztest and is only possible when
deduplication is enabled through the following call path.
Resolve the issue by always initializing scn_maxinflight_bytes
to a reasonable minimum value. This value will be recalculated
in dsl_scan_sync() to pick up changes to zfs_scan_vdev_limit
and the addition/removal of vdevs.
Reviewed-by: Tom Caputi <tcaputi@datto.com>
Reviewed by: George Melikov <mail@gmelikov.ru> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #7098