autofs-5.0.9 - amd lookup try to use external mounts for nfs mounts

From: Ian Kent <raven@themaw.net>

When using nfs type mounts they may be mounted externally to avoid
multiple instances of the mount.

The current usage doesn't always use external mounts when it can so,
if option fs is defined, use an external.
---
 modules/parse_amd.c |    7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/modules/parse_amd.c b/modules/parse_amd.c
index 0c708e6..becc519 100644
--- a/modules/parse_amd.c
+++ b/modules/parse_amd.c
@@ -1011,7 +1011,7 @@ static int do_nfs_mount(struct autofs_point *ap, const char *name,
 	if (proximity == PROXIMITY_OTHER && entry->remopts)
 		opts = entry->remopts;
 
-	if (!entry->sublink) {
+	if (!entry->fs) {
 		ret = mount_nfs->mount_mount(ap, ap->path, name, strlen(name),
 					     target, entry->type, opts,
 					     mount_nfs->context);
@@ -1214,6 +1214,11 @@ static unsigned int validate_nfs_options(unsigned int logopt,
 			return 0;
 		}
 	}
+	if (entry->sublink && !entry->fs) {
+		error(logopt, MODPREFIX
+		      "%s: sublink option requires option fs");
+		return 0;
+	}
 	return 1;
 }