zbd: do not check open zones status and limits when jobs do not write

zbd: do not check open zones status and limits when jobs do not write

Currently, fio checks the conditions of each zone within the IO range at
the job start. If a zone is in an open condition, it is added to the
write target zone array. If the number of write target zones exceeds the
max_open_zones or job_max_open_zones limit, fio terminates with the
error message "Number of open zones exceeds max_open_zones limit". This
check for zone condition and the resulting termination occur even when
the job does not perform a write operation, leading to confusion among
users.

To avoid the confusion, skip the check when jobs do not perform write
operations. Additionally, print the message to inform that the
job_max_open_zones limit does not work for non-write jobs.

Fixes: 954217b90191 ("zbd: Initialize open zones list referring zone status at fio start")
Fixes: 8ac768899d63 ("zbd: do not reset extra zones in open conditions")
Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Reviewed-by: Niklas Cassel <niklas.cassel@wdc.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/20250122013835.1223725-2-shinichiro.kawasaki@wdc.com
Signed-off-by: Vincent Fu <vincentfu@gmail.com>