Add total space to disk health information

Previously, disk health information only included the amount of free
space and the configured threshold. This commit adds the disk’s total
space.

See gh-2705

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/health/DiskSpaceHealthIndicator.java

@@ -16,6 +16,8 @@
 
 package org.springframework.boot.actuate.health;
 
+import java.io.File;
+
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.springframework.beans.factory.annotation.Autowired;
@@ -45,7 +47,8 @@ public class DiskSpaceHealthIndicator extends AbstractHealthIndicator {
 
 	@Override
 	protected void doHealthCheck(Health.Builder builder) throws Exception {
-		long diskFreeInBytes = this.properties.getPath().getFreeSpace();
+		File path = this.properties.getPath();
+		long diskFreeInBytes = path.getFreeSpace();
 		if (diskFreeInBytes >= this.properties.getThreshold()) {
 			builder.up();
 		}
@@ -55,7 +58,8 @@ public class DiskSpaceHealthIndicator extends AbstractHealthIndicator {
 					this.properties.getThreshold()));
 			builder.down();
 		}
-		builder.withDetail("free", diskFreeInBytes).withDetail("threshold",
-				this.properties.getThreshold());
+		builder.withDetail("total", path.getTotalSpace())
+				.withDetail("free", diskFreeInBytes)
+				.withDetail("threshold", this.properties.getThreshold());
 	}
 }