Fix crash on threads being reaped before they are created

If we do that, then ->rusage_sem is never allocated.

Signed-off-by: Jens Axboe <axboe@fb.com>
Add support for verify triggers

This allows you to (for instance) instantly terminate a verify
write workload, and then later that everything was written
correctly up to that very point. This can be useful for testing
powercut scenarios, which is often problematic on storage
devices.

Needs documentation, etc. But code should be mostly there, it
works both standalone and in the client/server model.

Signed-off-by: Jens Axboe <axboe@fb.com>
Add job name to the state filename

Signed-off-by: Jens Axboe <axboe@fb.com>
Rename load_verify_state to verify_load_state and add documentation

Signed-off-by: Jens Axboe <axboe@fb.com>
Allow for saving verify state on normal/timeout exit from a job

Signed-off-by: Jens Axboe <axboe@fb.com>
Add verify_state_save option

Then we can control this independently of the verify trigger. This
is useful for, eg, setting a timeout or amount of IO to be written,
then verify to that point later on.

Signed-off-by: Jens Axboe <axboe@fb.com>
server: always send all_io_list on VTRIGGER command

The client expects this, even if the list is empty.

Signed-off-by: Jens Axboe <axboe@fb.com>
verify: kill unused function

Signed-off-by: Jens Axboe <axboe@fb.com>
Prefix verify state files with destination

It'll be local- for a local run, sock- for over socket, and <ip>-
for when connected to a server.

Signed-off-by: Jens Axboe <axboe@fb.com>
backend: only create verify state files for verify + write

Signed-off-by: Jens Axboe <axboe@fb.com>