LU-16160 llite: SIGBUS is possible on a race with page reclaim

LU-16160 llite: SIGBUS is possible on a race with page reclaim

We can restart fault handling if page truncation happens
in parallel with the fault handler.

Change-Id: I6e60783e3334f87e799dc8b0e6e63d0bb358a236
Signed-off-by: Andrew Perepechko <andrew.perepechko@hpe.com>
Signed-off-by: Patrick Farrell <farr0186@gmail.com>
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/49647
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>