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: 954217b ("zbd: Initialize open zones list referring zone status at fio start")
Fixes: 8ac7688 ("zbd: do not reset extra zones in open conditions")
Signed-off-by: Shin'ichiro Kawasaki <[email protected]>
Reviewed-by: Niklas Cassel <[email protected]>
Reviewed-by: Damien Le Moal <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Vincent Fu <[email protected]>

Author: kawasaki

zbd.c

@@ -1264,6 +1264,16 @@ int zbd_setup_files(struct thread_data *td)
 			return 1;
 		}
 
+		/*
+		 * If this job does not do write operations, skip open zone
+		 * condition check.
+		 */
+		if (!td_write(td)) {
+			if (td->o.job_max_open_zones)
+				log_info("'job_max_open_zones' is valid only for write jobs\n");
+			continue;
+		}
+
 		/*
 		 * The per job max open zones limit cannot be used without a
 		 * global max open zones limit. (As the tracking of open zones