Index: e2fsprogs-1.39+1.40_WIP_20061114/lib/blkid/probe.c
===================================================================
--- e2fsprogs-1.39+1.40_WIP_20061114.orig/lib/blkid/probe.c
+++ e2fsprogs-1.39+1.40_WIP_20061114/lib/blkid/probe.c
@@ -148,6 +148,39 @@ static void get_ext2_info(blkid_dev dev,
 	set_uuid(dev, es->s_uuid, 0);
 }
 
+static int probe_ext4(struct blkid_probe *probe,
+		      struct blkid_magic *id __BLKID_ATTR((unused)),
+		      unsigned char *buf)
+{
+	struct ext2_super_block *es;
+	es = (struct ext2_super_block *)buf;
+
+	/* Distinguish between jbd and ext2/3 fs */
+	if (blkid_le32(es->s_feature_incompat) &
+	    EXT3_FEATURE_INCOMPAT_JOURNAL_DEV)
+		return -BLKID_ERR_PARAM;
+
+	/* Distinguish between ext3 and ext2 */
+	if (!(blkid_le32(es->s_feature_compat) &
+	      EXT3_FEATURE_COMPAT_HAS_JOURNAL))
+		return -BLKID_ERR_PARAM;
+
+	/* Distinguish between ext4 and ext3 */
+	if (!(blkid_le32(es->s_feature_incompat) &
+	      EXT3_FEATURE_INCOMPAT_EXTENTS))
+		return -BLKID_ERR_PARAM;
+
+	get_ext2_info(probe->dev, buf);
+
+	if ((es->s_feature_incompat & EXT3_FEATURE_COMPAT_HAS_JOURNAL) &&
+	    !uuid_is_null(es->s_journal_uuid))
+		set_uuid(probe->dev, es->s_journal_uuid, "EXT_JOURNAL");
+
+	blkid_set_tag(probe->dev, "SEC_TYPE", "ext2", sizeof("ext2"));
+
+	return 0;
+}
+
 static int probe_ext3(struct blkid_probe *probe, 
 		      struct blkid_magic *id __BLKID_ATTR((unused)), 
 		      unsigned char *buf)
@@ -710,6 +743,7 @@ static struct blkid_magic type_array[] =
 /*  type     kboff   sboff len  magic			probe */
   { "oracleasm", 0,	32,  8, "ORCLDISK",		probe_oracleasm },
   { "ntfs",      0,      3,  8, "NTFS    ",             0 },
+  { "ext4dev",	 1,   0x38,  2, "\123\357",		probe_ext4 },
   { "jbd",	 1,   0x38,  2, "\123\357",		probe_jbd },
   { "ext3",	 1,   0x38,  2, "\123\357",		probe_ext3 },
   { "ext2",	 1,   0x38,  2, "\123\357",		probe_ext2 },
Index: e2fsprogs-1.39+1.40_WIP_20061114/lib/blkid/probe.h
===================================================================
--- e2fsprogs-1.39+1.40_WIP_20061114.orig/lib/blkid/probe.h
+++ e2fsprogs-1.39+1.40_WIP_20061114/lib/blkid/probe.h
@@ -87,6 +87,8 @@ struct ext2_super_block {
 #define EXT3_FEATURE_COMPAT_HAS_JOURNAL		0x00000004
 #define EXT3_FEATURE_INCOMPAT_RECOVER		0x00000004
 #define EXT3_FEATURE_INCOMPAT_JOURNAL_DEV	0x00000008
+#define EXT3_FEATURE_INCOMPAT_EXTENTS		0x00000040
+
 
 struct xfs_super_block {
 	unsigned char	xs_magic[4];