1 files changed, 55 insertions, 0 deletions

diff --git a/fs/udf/partition.c b/fs/udf/partition.c
index b2e6e1eddb90..2dfe4be2eeb2 100644
--- a/fs/udf/partition.c
+++ b/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;
+}