In unattended operations it's often more useful to have node
panic and reboot when it encounters problems as opposed to
sit there indefinitely waiting for somebody to discover it.
This implements an spl_panic_crash module parameter, set it
to nonzero to cause spl_panic() to call panic().
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Signed-off-by: Oleg Drokin <green@linuxhacker.ru>
Closes#634