block/001: wait until device is added

Writing to the scan attribute of scsi host is usually one sync scan, but
devices in this sync scan may be delay added if there is concurrent
asnyc scan.

So wait until the device is added in block/001 for avoiding to fail
the test.

Cc: "Martin K. Petersen" <[email protected]>
Cc: [email protected]
Signed-off-by: Ming Lei <[email protected]>
[Omar: fix quoting and simplify logic]
Signed-off-by: Omar Sandoval <[email protected]>

Author: Ming Lei

tests/block/001

@@ -29,7 +29,13 @@ stress_scsi_debug() {
 		scan="${scan//:/ }"
 		while [[ ! -e "$TMPDIR/stop" ]]; do
 			echo "${scan}" > "/sys/class/scsi_host/host${host}/scan"
-			echo 1 > "/sys/class/scsi_device/${target}/device/delete"
+			while [[ ! -e "$TMPDIR/stop" ]]; do
+				if [[ -d "/sys/class/scsi_device/${target}" ]]; then
+					echo 1 > "/sys/class/scsi_device/${target}/device/delete"
+					break
+				fi
+				sleep 0.01
+			done
 		done
 		) &
 	done