libblkid: udf: Fix reporting UDF 2.60 revision

According to the UDF 2.60 specification, the Minimum UDF Read Revision
value shall be at most #0250 for all media with a UDF 2.60 file system.

So in this case use Minimum UDF Write Revision as ID_FS_VERSION to
distinguish between UDF 2.50 and UDF 2.60 discs.

This commit also adds a testing Blu-Ray Recordable image with UDF revision
2.60 created by Nero which really sets Minimum UDF Read Revision to 2.50.

Signed-off-by: Pali Rohár <pali.rohar@gmail.com>

libblkid/src/superblocks/udf.c

@@ -446,6 +446,16 @@ real_blksz:
 			lvidiu_udf_rev = le16_to_cpu(lvidiu->min_udf_read_rev);
 			if (lvidiu_udf_rev)
 				udf_rev = lvidiu_udf_rev;
+			/* UDF-2.60: 2. Basic Restrictions & Requirements:
+			 * The Minimum UDF Read Revision value shall be at most #0250
+			 * for all media with a UDF 2.60 file system.
+			 * So in this case use Minimum UDF Write Revision as ID_FS_VERSION
+			 * to distinguish between UDF 2.50 and UDF 2.60 discs. */
+			if (lvidiu_udf_rev == 0x250) {
+				lvidiu_udf_rev = le16_to_cpu(lvidiu->min_udf_write_rev);
+				if (lvidiu_udf_rev > 0x250)
+					udf_rev = lvidiu_udf_rev;
+			}
 		}
 	}
 

tests/expected/blkid/low-probe-udf-bdr-2.60-nero

@@ -0,0 +1,10 @@
+ID_FS_LABEL=Label
+ID_FS_LABEL_ENC=Label
+ID_FS_LOGICAL_VOLUME_ID=Label
+ID_FS_TYPE=udf
+ID_FS_USAGE=filesystem
+ID_FS_UUID=3b4a858dc4b57a72
+ID_FS_UUID_ENC=3b4a858dc4b57a72
+ID_FS_VERSION=2.60
+ID_FS_VOLUME_ID=Label
+ID_FS_VOLUME_SET_ID=3B4A858DC4B57A72