fadvise: always exit with EXIT_FAILURE on error

Also document it.

Signed-off-by: Thomas Weißschuh <thomas@t-8ch.de>

misc-utils/fadvise.1.adoc

@@ -41,6 +41,15 @@ If this option is omitted, 0 is used as default advice.
 
 include::man-common/help-version.adoc[]
 
+== EXIT STATUS
+
+*fadvise* has the following exit status values:
+
+*0*::
+success
+*1*::
+unspecified failure
+
 == AUTHORS
 
 mailto:yamato@redhat.com[Masatake YAMATO]

misc-utils/fadvise.c

@@ -158,5 +158,5 @@ int main(int argc, char ** argv)
 	if (do_close)
 		close(fd);
 
-	return rc;
+	return rc == 0 ? EXIT_SUCCESS : EXIT_FAILURE;
 }