[PATCH e2fsprogs] teach libblkid about ext4(dev)

[Eric Sandeen <sandeen@redhat.com>]

Returns ext4dev for now; will need to change to ext4 at the appropriate
time I guess.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>

--- 

Index: e2fsprogs-1.40.4/lib/blkid/probe.c

===================================================================
--- e2fsprogs-1.40.4.orig/lib/blkid/probe.c
+++ e2fsprogs-1.40.4/lib/blkid/probe.c
@@ -148,6 +148,38 @@ 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 ext2/3/4 fs */
+	if (blkid_le32(es->s_feature_incompat) &
+	    EXT3_FEATURE_INCOMPAT_JOURNAL_DEV)
+		return -BLKID_ERR_PARAM;
+
+	/* Distinguish between ext3/4 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_ro_compat) &
+	      EXT4_FEATURES_RO_COMPAT) &&
+	    !(blkid_le32(es->s_feature_incompat) &
+	      EXT4_FEATURES_INCOMPAT))
+		return -BLKID_ERR_PARAM;
+
+	get_ext2_info(probe->dev, buf);
+
+	if ((es->s_feature_compat & EXT3_FEATURE_COMPAT_HAS_JOURNAL) &&
+	    !uuid_is_null(es->s_journal_uuid))
+		set_uuid(probe->dev, es->s_journal_uuid, "EXT_JOURNAL");
+
+	return 0;
+}
 static int probe_ext3(struct blkid_probe *probe, 
 		      struct blkid_magic *id __BLKID_ATTR((unused)), 
 		      unsigned char *buf)
@@ -833,6 +865,7 @@ static struct blkid_magic type_array[] =
   { "oracleasm", 0,	32,  8, "ORCLDISK",		probe_oracleasm },
   { "ntfs",	 0,	 3,  8, "NTFS    ",		probe_ntfs },
   { "jbd",	 1,   0x38,  2, "\123\357",		probe_jbd },
+  { "ext4dev",	 1,   0x38,  2, "\123\357",		probe_ext4 },
   { "ext3",	 1,   0x38,  2, "\123\357",		probe_ext3 },
   { "ext2",	 1,   0x38,  2, "\123\357",		probe_ext2 },
   { "reiserfs",	 8,   0x34,  8, "ReIsErFs",		probe_reiserfs },
Index: e2fsprogs-1.40.4/lib/blkid/probe.h
===================================================================
--- e2fsprogs-1.40.4.orig/lib/blkid/probe.h
+++ e2fsprogs-1.40.4/lib/blkid/probe.h
@@ -88,6 +88,26 @@ struct ext2_super_block {
 #define EXT3_FEATURE_INCOMPAT_RECOVER		0x00000004
 #define EXT3_FEATURE_INCOMPAT_JOURNAL_DEV	0x00000008
 
+#define EXT4_FEATURE_RO_COMPAT_HUGE_FILE	0x0008
+#define EXT4_FEATURE_RO_COMPAT_GDT_CSUM		0x0010
+#define EXT4_FEATURE_RO_COMPAT_DIR_NLINK	0x0020
+#define EXT4_FEATURE_RO_COMPAT_EXTRA_ISIZE	0x0040
+
+#define EXT4_FEATURE_INCOMPAT_EXTENTS		0x0040 /* extents support */
+#define EXT4_FEATURE_INCOMPAT_64BIT		0x0080
+#define EXT4_FEATURE_INCOMPAT_MMP		0x0100
+#define EXT4_FEATURE_INCOMPAT_FLEX_BG		0x0200
+
+#define EXT4_FEATURES_RO_COMPAT	(EXT4_FEATURE_RO_COMPAT_HUGE_FILE| \
+				 EXT4_FEATURE_RO_COMPAT_GDT_CSUM| \
+				 EXT4_FEATURE_RO_COMPAT_DIR_NLINK| \
+				 EXT4_FEATURE_RO_COMPAT_EXTRA_ISIZE)
+
+#define EXT4_FEATURES_INCOMPAT	(EXT4_FEATURE_INCOMPAT_EXTENTS| \
+				 EXT4_FEATURE_INCOMPAT_64BIT| \
+				 EXT4_FEATURE_INCOMPAT_MMP| \
+				 EXT4_FEATURE_INCOMPAT_FLEX_BG)
+
 struct xfs_super_block {
 	unsigned char	xs_magic[4];
 	__u32		xs_blocksize;