From 329f7803ee4414cd015e6f83a835079208608171 Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Fri, 7 Mar 2014 03:30:30 +0100
Subject: udev: automatically create a symlink /dev/disk/by-id/gpt-auto-root if
 there's a suitable root partition

---
 rules/60-persistent-storage.rules |  3 +++
 src/udev/udev-builtin-blkid.c     | 15 +++++++++++++--
 2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/rules/60-persistent-storage.rules b/rules/60-persistent-storage.rules
index 4f7163da02..19e450de1c 100644
--- a/rules/60-persistent-storage.rules
+++ b/rules/60-persistent-storage.rules
@@ -84,4 +84,7 @@ ENV{DEVTYPE}=="partition", ENV{ID_WWN_WITH_EXTENSION}=="?*", SYMLINK+="disk/by-i
 ENV{ID_PART_ENTRY_SCHEME}=="gpt", ENV{ID_PART_ENTRY_UUID}=="?*", SYMLINK+="disk/by-partuuid/$env{ID_PART_ENTRY_UUID}"
 ENV{ID_PART_ENTRY_SCHEME}=="gpt", ENV{ID_PART_ENTRY_NAME}=="?*", SYMLINK+="disk/by-partlabel/$env{ID_PART_ENTRY_NAME}"
 
+# add symlink to GPT root disk
+ENV{ID_PART_ENTRY_SCHEME}=="gpt", ENV{ID_PART_GPT_AUTO_ROOT}=="1", SYMLINK+="disk/by-id/gpt-auto-root"
+
 LABEL="persistent_storage_end"
diff --git a/src/udev/udev-builtin-blkid.c b/src/udev/udev-builtin-blkid.c
index a49dd31b8b..5b976abd8d 100644
--- a/src/udev/udev-builtin-blkid.c
+++ b/src/udev/udev-builtin-blkid.c
@@ -174,9 +174,9 @@ static int find_gpt_root(struct udev_device *dev, blkid_probe pr, bool test) {
         }
 
         /* We found the ESP on this disk, and also found a root
-         * partition, nice! Let's export its UUID*/
+         * partition, nice! Let's export its UUID */
         if (found_esp && root_id)
-                udev_builtin_add_property(dev, test, "ID_PART_GPT_AUTO_ROOT", root_id);
+                udev_builtin_add_property(dev, test, "ID_PART_GPT_AUTO_ROOT_UUID", root_id);
 #endif
 
         return 0;
@@ -217,6 +217,7 @@ static int probe_superblocks(blkid_probe pr)
 
 static int builtin_blkid(struct udev_device *dev, int argc, char *argv[], bool test)
 {
+        const char *root_partition;
         int64_t offset = 0;
         bool noraid = false;
         _cleanup_close_ int fd = -1;
@@ -282,6 +283,10 @@ static int builtin_blkid(struct udev_device *dev, int argc, char *argv[], bool t
         if (err < 0)
                 goto out;
 
+        /* If we are a partition then our parent passed on the root
+         * partition UUID to us */
+        root_partition = udev_device_get_property_value(dev, "ID_PART_GPT_AUTO_ROOT_UUID");
+
         nvals = blkid_probe_numof_values(pr);
         for (i = 0; i < nvals; i++) {
                 if (blkid_probe_get_value(pr, i, &name, &data, &len))
@@ -290,8 +295,14 @@ static int builtin_blkid(struct udev_device *dev, int argc, char *argv[], bool t
                 len = strnlen((char *) data, len);
                 print_property(dev, test, name, (char *) data);
 
+                /* Is this a disk with GPT partition table? */
                 if (streq(name, "PTTYPE") && streq(data, "gpt"))
                         is_gpt = true;
+
+                /* Is this a partition that matches the root partition
+                 * property we inherited from our parent? */
+                if (root_partition && streq(name, "PART_ENTRY_UUID") && streq(data, root_partition))
+                        udev_builtin_add_property(dev, test, "ID_PART_GPT_AUTO_ROOT", "1");
         }
 
         if (is_gpt)
-- 
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