Move actually mounting the root filesystem into its own series of hooks.

We now have mount hooks.  They are sourced in an infinite loop until one of
them actually mounts the real root filesystem.

This makes it easier to add support for arbitrarily complex schemes to find
the root filesystem without having to patch the init script.

This patch series is also avaialble ass the hookify-finding-root branch at
http://git.fnordovax.org/dracut

hooks/mount-partition.sh

@@ -0,0 +1,30 @@
+#!/bin/sh
+[ "$root" ] || {
+    root=$(getarg root); root=${root#root=}
+    case $root in
+	LABEL=*) root=${root#LABEL=}
+            root="$(echo $root |sed 's,/,\\x2f,g')"
+            root="/dev/disk/by-label/${root}" ;;
+        UUID=*) root="/dev/disk/by-uuid/${root#UUID=}" ;;
+        '') echo "Warning: no root specified"
+            root="/dev/sda1" ;;
+    esac
+}
+
+[ "$rflags" ] || {
+    if rflags="$(getarg rootflags)"; then
+	rflags="${rflags#rootflags=}"
+	getarg rw >/dev/null && rflags="${rflags},rw" || rflags="${rflags},ro"
+    else
+	getarg rw >/dev/null && rflags=rw || rflags=ro
+    fi
+}
+
+[ "$fstype" ] || {
+    fstype="$(getarg rootfstype)" && fstype="-t ${fstype#rootfstype=}"
+}
+
+[ -e "$root" ] && {
+    ln -sf "$root" /dev/root
+    mount $fstype -o $rflags /dev/root $NEWROOT && ROOTFS_MOUNTED=yes
+}

init

@@ -50,45 +50,31 @@ mknod /dev/tty0 c 4 0
 mknod /dev/tty1 c 4 1
 mknod /dev/null c 1 3
 
+# pre-udev scripts run before udev starts, and are run only once.
 source_all pre-udev
 
 # start up udev and trigger cold plugs
 udevd --daemon
 udevadm trigger >/dev/null 2>&1
-
-# mount the rootfs
-NEWROOT="/sysroot"
-
-# FIXME: there's got to be a better way ...
-# it'd be nice if we had a udev rule that just did all of the bits for
-# figuring out what the specified root is and linking it /dev/root
-root=$(getarg root); root=${root#root=}
-case $root in
-    LABEL=*) root=${root#LABEL=}
-             root="$(echo $root |sed 's,/,\\x2f,g')"
-	     root="/dev/disk/by-label/${root}" ;;
-    UUID=*) root="/dev/disk/by-uuid/${root#UUID=}" ;;
-    '') echo "Warning: no root specified"
-	root="/dev/sda1" ;;
-esac
-
-# should we have a timeout?
-tries=0
-echo "Waiting up to 30 seconds for $root to become available"
 udevadm settle --timeout=30
+
+NEWROOT="/sysroot"
+# pre-mount happens before we try to mount the root filesystem,
+# and happens once.
 source_all pre-mount
 
-echo "Trying to mount rootfs $root"
-if rflags="$(getarg rootflags)"; then
-    rflags="${rflags#rootflags=}"
-    getarg rw >/dev/null && rflags="${rflags},rw" || rflags="${rflags},ro"
-else
-     getarg rw >/dev/null && rflags=rw || rflags=ro
-fi
-[ -e "$root" ] || emergency_shell
-ln -s "$root" /dev/root 
-fstype="$(getarg rootfstype)" && fstype="-t ${fstype#rootfstype=}" 
-mount $fstype -o $rflags /dev/root $NEWROOT || emergency_shell
+# mount scripts actually try to mount the root filesystem, and may
+# be sourced any number of times. As soon as one suceeds, no more are sourced.
+while :; do
+    for f in /mount/*.sh; do
+	[ -x "$f" ] && . "$f";
+	[ "$ROOTFS_MOUNTED" ] && break;
+    done
+    [ "$ROOTFS_MOUNTED" ] && break;
+    sleep 1
+done
+
+# by the time we get here, the root filesystem should be mounted.
 
 INIT=$(getarg init)
 [ "$INIT" ] || {
@@ -101,7 +87,8 @@ INIT=$(getarg init)
 	emergency_shell
     }
 }
-	    
+
+# pre pivot scripts are sourced just before we switch over to the new root.
 source_all pre-pivot
 echo "Switching to real root filesystem $root"
 exec switch_root "$NEWROOT" "$INIT"  $CMDLINE || {

modules/90crypt.sh

@@ -1,4 +1,4 @@
 #!/bin/bash
 inst cryptsetup
 inst_rules "$dsrc/rules.d/63-luks.rules"
-inst_hook pre-mount 50 "$dsrc/hooks/cryptroot.sh"
+inst_hook mount 10 "$dsrc/hooks/cryptroot.sh"

modules/99base.sh

@@ -4,5 +4,5 @@ dracut_install mount mknod mkdir modprobe pidof sleep chroot echo sed sh ls
 inst "$initfile" "/init"
 inst "$switchroot" "/sbin/switch_root"
 inst_hook pre-pivot 50 "$dsrc/hooks/selinux-loadpolicy.sh"
-inst_hook pre-mount 99 "$dsrc/hooks/resume.sh"
-
+inst_hook mount 90 "$dsrc/hooks/resume.sh"
+inst_hook mount 99 "$dsrc/hooks/mount-partition.sh"