udf: Add read-only support for 2.50 UDF media

This patch implements parsing of metadata partitions and reading of Metadata
File thus allowing to read UDF 2.50 media. Error resilience is implemented
through accessing the Metadata Mirror File in case the data the Metadata File
cannot be read. The patch is based on the original patch by Sebastian Manciulea
<manciuleas@yahoo.com> and Mircea Fedoreanu <mirceaf_spl@yahoo.com>.

Signed-off-by: Sebastian Manciulea <manciuleas@yahoo.com>
Signed-off-by: Mircea Fedoreanu <mirceaf_spl@yahoo.com>
Signed-off-by: Jan Kara <jack@suse.cz>

1 files changed, 15 insertions, 1 deletions

diff --git a/fs/udf/udf_sb.h b/fs/udf/udf_sb.h
index 8308a12e1232..1c1c514a9725 100644
--- a/fs/udf/udf_sb.h
+++ b/fs/udf/udf_sb.h
@@ -6,7 +6,7 @@
 /* Since UDF 2.01 is ISO 13346 based... */
 #define UDF_SUPER_MAGIC                 0x15013346
 
-#define UDF_MAX_READ_VERSION            0x0201
+#define UDF_MAX_READ_VERSION            0x0250
 #define UDF_MAX_WRITE_VERSION           0x0201
 
 #define UDF_FLAG_USE_EXTENDED_FE        0
@@ -46,9 +46,22 @@
 #define UDF_VIRTUAL_MAP15               0x1512U
 #define UDF_VIRTUAL_MAP20               0x2012U
 #define UDF_SPARABLE_MAP15              0x1522U
+#define UDF_METADATA_MAP25              0x2511U
 
 #pragma pack(1) /* XXX(hch): Why?  This file just defines in-core structures */
 
+struct udf_meta_data {
+        __u32   s_meta_file_loc;
+        __u32   s_mirror_file_loc;
+        __u32   s_bitmap_file_loc;
+        __u32   s_alloc_unit_size;
+        __u16   s_align_unit_size;
+        __u8    s_dup_md_flag;
+        struct inode *s_metadata_fe;
+        struct inode *s_mirror_fe;
+        struct inode *s_bitmap_fe;
+};
+
 struct udf_sparing_data {
         __u16   s_packet_len;
         struct buffer_head *s_spar_map[4];
@@ -82,6 +95,7 @@ struct udf_part_map {
         union {
                 struct udf_sparing_data s_sparing;
                 struct udf_virtual_data s_virtual;
+                struct udf_meta_data s_metadata;
         } s_type_specific;
         __u32   (*s_partition_func)(struct super_block *, __u32, __u16, __u32);
         __u16   s_volumeseqnum;