Index: head/libexec/rc/rc.conf
===================================================================
--- head/libexec/rc/rc.conf
+++ head/libexec/rc/rc.conf
@@ -101,6 +101,7 @@
 
 root_rw_mount="YES"	# Set to NO to inhibit remounting root read-write.
 root_hold_delay="30"	# Time to wait for root mount hold release.
+fsck_flags="-p"		# May be changed to -f (or -f -y) to force a full fsck
 fsck_y_enable="NO"	# Set to YES to do fsck -y if the initial preen fails.
 fsck_y_flags="-T ffs:-R -T ufs:-R"	# Additional flags for fsck -y
 background_fsck="YES"	# Attempt to run fsck in the background where possible.
Index: head/libexec/rc/rc.d/fsck
===================================================================
--- head/libexec/rc/rc.d/fsck
+++ head/libexec/rc/rc.d/fsck
@@ -25,10 +25,11 @@
 		trap : 3
 
 		check_startmsgs && echo "Starting file system checks:"
+		# Background fsck can only be run with -p
 		if checkyesno background_fsck; then
 			fsck -F -p
 		else
-			fsck -p
+			fsck ${fsck_flags}
 		fi
 
 		err=$?
@@ -37,10 +38,11 @@
 			    "available; retrying"
 			root_hold_wait
 			check_startmsgs && echo "Restarting file system checks:"
+			# Background fsck can only be run with -p
 			if checkyesno background_fsck; then
 				fsck -F -p
 			else
-				fsck -p
+				fsck ${fsck_flags}
 			fi
 			err=$?
 		fi