linuxrc /usr mounting

Dogfooding of the /usr mount code with the matching OpenRC change to
make the mounts RW revealed some bugs and gotchas in our prior code, now
fixed and verified to work.

Signed-off-by: Robin H. Johnson <robbat2@gentoo.org>

ChangeLog

@@ -5,6 +5,12 @@
 # Distributed under the GPL v2
 # $Id$
 
+  09 Feb 2012; Robin H. Johnson <robbat2@gentoo.org> defaults/initrd.scripts,
+  defaults/linuxrc:
+  Dogfooding of the /usr mount code with the matching OpenRC change to make the
+  mounts RW revealed some bugs and gotchas in our prior code, now fixed and
+  verified to work.
+
   06 Feb 2012; Robin H. Johnson <robbat2@gentoo.org> arch/alpha/config.sh,
   arch/arm/config.sh, arch/ia64/config.sh, arch/mips/config.sh,
   arch/parisc/config.sh, arch/parisc64/config.sh, arch/ppc/config.sh,

defaults/initrd.scripts

@@ -1199,7 +1199,7 @@ get_mounts_list()
 		' ${NEW_ROOT}/etc/initramfs.mounts
 }
 
-get_mount_options()
+get_mount_fstype()
 {
 	awk -v fs="$1" '
 		/^[[:blank:]]*#/ { next }
@@ -1207,6 +1207,14 @@ get_mount_options()
 		' ${NEW_ROOT}/etc/fstab
 }
 
+get_mount_options()
+{
+	awk -v fs="$1" '
+		/^[[:blank:]]*#/ { next }
+		$2 == fs { print $4 }
+		' ${NEW_ROOT}/etc/fstab
+}
+
 get_mount_device()
 {
 	awk -v fs="$1" '
@@ -1215,3 +1223,12 @@ get_mount_device()
 		' ${NEW_ROOT}/etc/fstab
 }
 
+# If the kernel is handed a mount option is does not recognize, it WILL fail to
+# mount. util-linux handles auto/noauto, but busybox passes it straight to the kernel
+# which then rejects the mount.
+# To make like a little easier, busybox mount does not care about leading,
+# trailing or duplicate commas.
+strip_mount_options()
+{
+	sed -r 's/(,|^)(no)?auto(,|$)/,/g'
+}

defaults/linuxrc

@@ -531,7 +531,7 @@ do
 		# there is no isofs filesystem to worry about
 		break
 	else
-		good_msg "Mounting root..."
+		good_msg "Mounting $REAL_ROOT as root..."
 
 		if [ "${ROOTFSTYPE}" = 'zfs' ]
 		then
@@ -780,9 +780,14 @@ for fs in $fslist; do
 	# In this case, it's probably part of the filesystem
 	# and not a mountpoint
 	[ -z "$dev" ] && continue
-	opts="ro,$(get_mount_options \"$fs\")"
-	if ! mount -o ${opts} $dev ${NEW_ROOT}${fs}; then
-		rescue_shell "Unable to mount $dev on $fs"
+	fstype=$(get_mount_fstype $fs)
+	# ro must be trailing, and the options will always contain at least 'defaults'
+	opts="$(get_mount_options $fs | strip_mount_options),ro"
+	mnt=${NEW_ROOT}${fs}
+	cmd="mount -t $fstype -o $opts $dev $mnt"
+	good_msg "Mounting $dev as ${fs}: $cmd"
+	if ! $cmd; then
+		bad_msg "Unable to mount $dev for $fs"
 	fi
 done