Improve swap handling

Modify the swap script so it starts before and stops after localmount.
Also, on linux, this script should skip mounting swap on loopback.

Add a swapfiles script which runs after localmount and is designed to
activate additional swap space which could not be activated before
localmount was run. This includes loopback swap on linux and swapfiles
which are on local file systems that were not mounted when swap was
activated initially.

The start code does reactivate swap that is already active, but this is
not an error condition.

Reported-by: Giampaolo Tomassoni <giampaolo@tomassoni.biz>
X-Gentoo-Bug: 401003
X-Gentoo-Bug-URL: https://bugs.gentoo.org/show_bug.cgi?id=401003

init.d/Makefile

@@ -1,7 +1,7 @@
 DIR=	${INITDIR}
 SRCS=	bootmisc.in fsck.in hostname.in local.in localmount.in netmount.in \
-	network.in root.in savecache.in staticroute.in swap.in swclock.in \
-	sysctl.in urandom.in ${SRCS-${OS}}
+	network.in root.in savecache.in staticroute.in swap.in swapfiles.in \
+	swclock.in sysctl.in urandom.in ${SRCS-${OS}}
 BIN=	${OBJS}
 
 INSTALLAFTER=	_installafter_net.lo

init.d/swap.in

@@ -4,7 +4,7 @@
 
 depend()
 {
-	need localmount
+	before localmount
 	keyword -jail -openvz -prefix -vserver -lxc
 }
 
@@ -12,6 +12,15 @@ start()
 {
 	ebegin "Activating swap devices"
 	case "$RC_UNAME" in
+		Linux)
+			local dev
+			for dev in $(fstabinfo -b -t swap); do
+				case "$dev" in
+					/dev/loop*) ;;
+					*) swapon $dev 2>/dev/null;;
+				esac
+			done
+			;;
 		NetBSD|OpenBSD) swapctl -A -t noblk >/dev/null;;
 		*)		swapon -a >/dev/null;;
 	esac

init.d/swapfiles.in

@@ -0,0 +1,45 @@
+#!@PREFIX@/sbin/runscript
+# Copyright (c) 2007-2009 Roy Marples <roy@marples.name>
+# Released under the 2-clause BSD license.
+
+depend()
+{
+	need localmount
+	keyword -jail -openvz -prefix -vserver -lxc
+}
+
+start()
+{
+	ebegin "Activating additional swap space"
+	case "$RC_UNAME" in
+		NetBSD|OpenBSD) swapctl -A -t noblk >/dev/null;;
+		*)		swapon -a >/dev/null;;
+	esac
+	eend 0 # If swapon has nothing todo it errors, so always return 0
+}
+
+stop()
+{
+	ebegin "Deactivating additional swap space"
+
+	# Try to unmount all tmpfs filesystems not in use, else a deadlock may
+	# occur. As $RC_SVCDIR may also be tmpfs we cd to it to lock it
+	# fixme: Do we need this here since we are only unmounting swap files
+	# and loopback swap?
+	cd "$RC_SVCDIR"
+	umount -a -t tmpfs 2>/dev/null
+
+	case "$RC_UNAME" in
+		Linux)
+			while read filename type rest; do
+				case "$type" in
+					file) swapoff $filename >/dev/null;;
+				esac
+				case "$filename" in
+					/dev/loop*) swapoff $filename >/dev/null;;
+				esac
+			done < /proc/swaps
+			;;
+	esac
+	eend 0
+}

runlevels/Makefile

@@ -1,5 +1,5 @@
 BOOT=		bootmisc fsck hostname localmount \
-		root swap sysctl urandom ${BOOT-${OS}}
+		root swap swapfiles sysctl urandom ${BOOT-${OS}}
 DEFAULT=	local netmount
 SHUTDOWN=	savecache ${SHUTDOWN-${OS}}
 SYSINIT=	${SYSINIT-${OS}}