From 57e275a08d46f976ab2a2edf9b7b507bbca1d1ca Mon Sep 17 00:00:00 2001
From: Dave Reisner <dreisner@archlinux.org>
Date: Fri, 2 Mar 2012 21:09:49 -0500
Subject: init_functions: lazily resolve UUID/LABEL tags

Relying on blkid to do tag resolution will fail when the root device
doesn't yet exist. This is, of course, bad for USB root devices.

Signed-off-by: Dave Reisner <dreisner@archlinux.org>
---
 init_functions | 27 ++++++++++++++++++++++-----
 1 file changed, 22 insertions(+), 5 deletions(-)

diff --git a/init_functions b/init_functions
index e9a0cb9..bf6f11a 100644
--- a/init_functions
+++ b/init_functions
@@ -154,16 +154,33 @@ fsck_root() {
 }
 
 resolve_device() {
-    local major minor dev device=$1
+    local major minor dev tagval device=$1
 
+    # do lazy resolution of devices by tag when udev is
+    # available. this allows us to wait on disks that
+    # might not show up immediately (e.g. USB). If udev
+    # isn't running, fall back on using blkid.
     case $device in
-        # resolve tag name to block device
-        UUID=*|LABEL=*)
-            dev=$(blkid -lt "$device" -o device)
-            [ -n "$device" ] && device=$dev
+        UUID=*)
+            tagval=${device#*=}
+            if [ "$udevd_running" -eq 1 ]; then
+                dev=/dev/disk/by-uuid/$tagval
+            else
+                dev=$(blkid -U "$tagval")
+            fi
+            ;;
+        LABEL=*)
+            tagval=${device#*=}
+            if [ "$udevd_running" -eq 1 ]; then
+                dev=/dev/disk/by-label/$tagval
+            else
+                dev=$(blkid -L "$tagval")
+            fi
             ;;
     esac
 
+    [ -n "$dev" ] && device=$dev
+
     case $device in
         /dev/*)
             if poll_device "$device" "$rootdelay"; then
-- 
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