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>

fs/udf/inode.c

@@ -1301,6 +1301,15 @@ static void udf_fill_inode(struct inode *inode, struct buffer_head *bh)
 		inode->i_op = &page_symlink_inode_operations;
 		inode->i_mode = S_IFLNK | S_IRWXUGO;
 		break;
+	case ICBTAG_FILE_TYPE_MAIN:
+		udf_debug("METADATA FILE-----\n");
+		break;
+	case ICBTAG_FILE_TYPE_MIRROR:
+		udf_debug("METADATA MIRROR FILE-----\n");
+		break;
+	case ICBTAG_FILE_TYPE_BITMAP:
+		udf_debug("METADATA BITMAP FILE-----\n");
+		break;
 	default:
 		printk(KERN_ERR "udf: udf_fill_inode(ino %ld) failed unknown "
 				"file type=%d\n", inode->i_ino,

fs/udf/partition.c

@@ -266,3 +266,58 @@ int udf_relocate_blocks(struct super_block *sb, long old_block, long *new_block)
 
 	return 0;
 }
+
+static uint32_t udf_try_read_meta(struct inode *inode, uint32_t block,
+					uint16_t partition, uint32_t offset)
+{
+	struct super_block *sb = inode->i_sb;
+	struct udf_part_map *map;
+	kernel_lb_addr eloc;
+	uint32_t elen;
+	sector_t ext_offset;
+	struct extent_position epos = {};
+	uint32_t phyblock;
+
+	if (inode_bmap(inode, block, &epos, &eloc, &elen, &ext_offset) !=
+						(EXT_RECORDED_ALLOCATED >> 30))
+		phyblock = 0xFFFFFFFF;
+	else {
+		map = &UDF_SB(sb)->s_partmaps[partition];
+		/* map to sparable/physical partition desc */
+		phyblock = udf_get_pblock(sb, eloc.logicalBlockNum,
+			map->s_partition_num, ext_offset + offset);
+	}
+
+	brelse(epos.bh);
+	return phyblock;
+}
+
+uint32_t udf_get_pblock_meta25(struct super_block *sb, uint32_t block,
+				uint16_t partition, uint32_t offset)
+{
+	struct udf_sb_info *sbi = UDF_SB(sb);
+	struct udf_part_map *map;
+	struct udf_meta_data *mdata;
+	uint32_t retblk;
+	struct inode *inode;
+
+	udf_debug("READING from METADATA\n");
+
+	map = &sbi->s_partmaps[partition];
+	mdata = &map->s_type_specific.s_metadata;
+	inode = mdata->s_metadata_fe ? : mdata->s_mirror_fe;
+
+	/* We shouldn't mount such media... */
+	BUG_ON(!inode);
+	retblk = udf_try_read_meta(inode, block, partition, offset);
+	if (retblk == 0xFFFFFFFF) {
+		udf_warning(sb, __func__, "error reading from METADATA, "
+			"trying to read from MIRROR");
+		inode = mdata->s_mirror_fe;
+		if (!inode)
+			return 0xFFFFFFFF;
+		retblk = udf_try_read_meta(inode, block, partition, offset);
+	}
+
+	return retblk;
+}

fs/udf/super.c

@@ -950,6 +950,101 @@ static int udf_load_pvoldesc(struct super_block *sb, sector_t block)
 	return 0;
 }
 
+static int udf_load_metadata_files(struct super_block *sb, int partition)
+{
+	struct udf_sb_info *sbi = UDF_SB(sb);
+	struct udf_part_map *map;
+	struct udf_meta_data *mdata;
+	kernel_lb_addr addr;
+	int fe_error = 0;
+
+	map = &sbi->s_partmaps[partition];
+	mdata = &map->s_type_specific.s_metadata;
+
+	/* metadata address */
+	addr.logicalBlockNum =  mdata->s_meta_file_loc;
+	addr.partitionReferenceNum = map->s_partition_num;
+
+	udf_debug("Metadata file location: block = %d part = %d\n",
+			  addr.logicalBlockNum, addr.partitionReferenceNum);
+
+	mdata->s_metadata_fe = udf_iget(sb, addr);
+
+	if (mdata->s_metadata_fe == NULL) {
+		udf_warning(sb, __func__, "metadata inode efe not found, "
+				"will try mirror inode.");
+		fe_error = 1;
+	} else if (UDF_I(mdata->s_metadata_fe)->i_alloc_type !=
+		 ICBTAG_FLAG_AD_SHORT) {
+		udf_warning(sb, __func__, "metadata inode efe does not have "
+			"short allocation descriptors!");
+		fe_error = 1;
+		iput(mdata->s_metadata_fe);
+		mdata->s_metadata_fe = NULL;
+	}
+
+	/* mirror file entry */
+	addr.logicalBlockNum = mdata->s_mirror_file_loc;
+	addr.partitionReferenceNum = map->s_partition_num;
+
+	udf_debug("Mirror metadata file location: block = %d part = %d\n",
+			  addr.logicalBlockNum, addr.partitionReferenceNum);
+
+	mdata->s_mirror_fe = udf_iget(sb, addr);
+
+	if (mdata->s_mirror_fe == NULL) {
+		if (fe_error) {
+			udf_error(sb, __func__, "mirror inode efe not found "
+			"and metadata inode is missing too, exiting...");
+			goto error_exit;
+		} else
+			udf_warning(sb, __func__, "mirror inode efe not found,"
+					" but metadata inode is OK");
+	} else if (UDF_I(mdata->s_mirror_fe)->i_alloc_type !=
+		 ICBTAG_FLAG_AD_SHORT) {
+		udf_warning(sb, __func__, "mirror inode efe does not have "
+			"short allocation descriptors!");
+		iput(mdata->s_mirror_fe);
+		mdata->s_mirror_fe = NULL;
+		if (fe_error)
+			goto error_exit;
+	}
+
+	/*
+	 * bitmap file entry
+	 * Note:
+	 * Load only if bitmap file location differs from 0xFFFFFFFF (DCN-5102)
+	*/
+	if (mdata->s_bitmap_file_loc != 0xFFFFFFFF) {
+		addr.logicalBlockNum = mdata->s_bitmap_file_loc;
+		addr.partitionReferenceNum = map->s_partition_num;
+
+		udf_debug("Bitmap file location: block = %d part = %d\n",
+			addr.logicalBlockNum, addr.partitionReferenceNum);
+
+		mdata->s_bitmap_fe = udf_iget(sb, addr);
+
+		if (mdata->s_bitmap_fe == NULL) {
+			if (sb->s_flags & MS_RDONLY)
+				udf_warning(sb, __func__, "bitmap inode efe "
+					"not found but it's ok since the disc"
+					" is mounted read-only");
+			else {
+				udf_error(sb, __func__, "bitmap inode efe not "
+					"found and attempted read-write mount");
+				goto error_exit;
+			}
+		}
+	}
+
+	udf_debug("udf_load_metadata_files Ok\n");
+
+	return 0;
+
+error_exit:
+	return 1;
+}
+
 static void udf_load_fileset(struct super_block *sb, struct buffer_head *bh,
 			     kernel_lb_addr *root)
 {
@@ -1169,7 +1264,7 @@ static int udf_load_partdesc(struct super_block *sb, sector_t block)
 	p = (struct partitionDesc *)bh->b_data;
 	partitionNumber = le16_to_cpu(p->partitionNumber);
 
-	/* First scan for TYPE1 and SPARABLE partitions */
+	/* First scan for TYPE1, SPARABLE and METADATA partitions */
 	for (i = 0; i < sbi->s_partitions; i++) {
 		map = &sbi->s_partmaps[i];
 		udf_debug("Searching map: (%d == %d)\n",
@@ -1189,8 +1284,8 @@ static int udf_load_partdesc(struct super_block *sb, sector_t block)
 	ret = udf_fill_partdesc_info(sb, p, i);
 
 	/*
-	 * Now rescan for VIRTUAL partitions when TYPE1 partitions are
-	 * already set up
+	 * Now rescan for VIRTUAL or METADATA partitions when SPARABLE and
+	 * PHYSICAL partitions are already set up
 	 */
 	type1_idx = i;
 	for (i = 0; i < sbi->s_partitions; i++) {
@@ -1198,7 +1293,8 @@ static int udf_load_partdesc(struct super_block *sb, sector_t block)
 
 		if (map->s_partition_num == partitionNumber &&
 		    (map->s_partition_type == UDF_VIRTUAL_MAP15 ||
-		     map->s_partition_type == UDF_VIRTUAL_MAP20))
+		     map->s_partition_type == UDF_VIRTUAL_MAP20 ||
+		     map->s_partition_type == UDF_METADATA_MAP25))
 			break;
 	}
 
@@ -1208,16 +1304,28 @@ static int udf_load_partdesc(struct super_block *sb, sector_t block)
 	ret = udf_fill_partdesc_info(sb, p, i);
 	if (ret)
 		goto out_bh;
-	/*
-	 * Mark filesystem read-only if we have a partition with virtual map
-	 * since we don't handle writing to it (we overwrite blocks instead of
-	 * relocating them).
-	 */
-	sb->s_flags |= MS_RDONLY;
-	printk(KERN_NOTICE "UDF-fs: Filesystem marked read-only because "
-		"writing to pseudooverwrite partition is not implemented.\n");
 
-	ret = udf_load_vat(sb, i, type1_idx);
+	if (map->s_partition_type == UDF_METADATA_MAP25) {
+		ret = udf_load_metadata_files(sb, i);
+		if (ret) {
+			printk(KERN_ERR "UDF-fs: error loading MetaData "
+			"partition map %d\n", i);
+			goto out_bh;
+		}
+	} else {
+		ret = udf_load_vat(sb, i, type1_idx);
+		if (ret)
+			goto out_bh;
+		/*
+		 * Mark filesystem read-only if we have a partition with
+		 * virtual map since we don't handle writing to it (we
+		 * overwrite blocks instead of relocating them).
+		 */
+		sb->s_flags |= MS_RDONLY;
+		printk(KERN_NOTICE "UDF-fs: Filesystem marked read-only "
+			"because writing to pseudooverwrite partition is "
+			"not implemented.\n");
+	}
 out_bh:
 	/* In case loading failed, we handle cleanup in udf_fill_super */
 	brelse(bh);
@@ -1316,6 +1424,50 @@ static int udf_load_logicalvol(struct super_block *sb, sector_t block,
 					}
 				}
 				map->s_partition_func = udf_get_pblock_spar15;
+			} else if (!strncmp(upm2->partIdent.ident,
+						UDF_ID_METADATA,
+						strlen(UDF_ID_METADATA))) {
+				struct udf_meta_data *mdata =
+					&map->s_type_specific.s_metadata;
+				struct metadataPartitionMap *mdm =
+						(struct metadataPartitionMap *)
+						&(lvd->partitionMaps[offset]);
+				udf_debug("Parsing Logical vol part %d "
+					"type %d  id=%s\n", i, type,
+					UDF_ID_METADATA);
+
+				map->s_partition_type = UDF_METADATA_MAP25;
+				map->s_partition_func = udf_get_pblock_meta25;
+
+				mdata->s_meta_file_loc   =
+					le32_to_cpu(mdm->metadataFileLoc);
+				mdata->s_mirror_file_loc =
+					le32_to_cpu(mdm->metadataMirrorFileLoc);
+				mdata->s_bitmap_file_loc =
+					le32_to_cpu(mdm->metadataBitmapFileLoc);
+				mdata->s_alloc_unit_size =
+					le32_to_cpu(mdm->allocUnitSize);
+				mdata->s_align_unit_size =
+					le16_to_cpu(mdm->alignUnitSize);
+				mdata->s_dup_md_flag 	 =
+					mdm->flags & 0x01;
+
+				udf_debug("Metadata Ident suffix=0x%x\n",
+					(le16_to_cpu(
+					 ((__le16 *)
+					      mdm->partIdent.identSuffix)[0])));
+				udf_debug("Metadata part num=%d\n",
+					le16_to_cpu(mdm->partitionNum));
+				udf_debug("Metadata part alloc unit size=%d\n",
+					le32_to_cpu(mdm->allocUnitSize));
+				udf_debug("Metadata file loc=%d\n",
+					le32_to_cpu(mdm->metadataFileLoc));
+				udf_debug("Mirror file loc=%d\n",
+				       le32_to_cpu(mdm->metadataMirrorFileLoc));
+				udf_debug("Bitmap file loc=%d\n",
+				       le32_to_cpu(mdm->metadataBitmapFileLoc));
+				udf_debug("Duplicate Flag: %d %d\n",
+					mdata->s_dup_md_flag, mdm->flags);
 			} else {
 				udf_debug("Unknown ident: %s\n",
 					  upm2->partIdent.ident);
@@ -1677,6 +1829,7 @@ static void udf_sb_free_bitmap(struct udf_bitmap *bitmap)
 static void udf_free_partition(struct udf_part_map *map)
 {
 	int i;
+	struct udf_meta_data *mdata;
 
 	if (map->s_partition_flags & UDF_PART_FLAG_UNALLOC_TABLE)
 		iput(map->s_uspace.s_table);
@@ -1689,6 +1842,17 @@ static void udf_free_partition(struct udf_part_map *map)
 	if (map->s_partition_type == UDF_SPARABLE_MAP15)
 		for (i = 0; i < 4; i++)
 			brelse(map->s_type_specific.s_sparing.s_spar_map[i]);
+	else if (map->s_partition_type == UDF_METADATA_MAP25) {
+		mdata = &map->s_type_specific.s_metadata;
+		iput(mdata->s_metadata_fe);
+		mdata->s_metadata_fe = NULL;
+
+		iput(mdata->s_mirror_fe);
+		mdata->s_mirror_fe = NULL;
+
+		iput(mdata->s_bitmap_fe);
+		mdata->s_bitmap_fe = NULL;
+	}
 }
 
 static int udf_fill_super(struct super_block *sb, void *options, int silent)

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;

fs/udf/udfdecl.h

@@ -177,6 +177,8 @@ extern uint32_t udf_get_pblock_virt20(struct super_block *, uint32_t, uint16_t,
 				      uint32_t);
 extern uint32_t udf_get_pblock_spar15(struct super_block *, uint32_t, uint16_t,
 				      uint32_t);
+extern uint32_t udf_get_pblock_meta25(struct super_block *, uint32_t, uint16_t,
+					  uint32_t);
 extern int udf_relocate_blocks(struct super_block *, long, long *);
 
 /* unicode.c */