X-Git-Url: https://code.delx.au/refind/blobdiff_plain/2e4421a5f190f66f21cc95e0be9f40106621c409..9b877e67c541f1c08950930a0ad8e0c6ee2ea2e9:/filesystems/fsw_ext4.c diff --git a/filesystems/fsw_ext4.c b/filesystems/fsw_ext4.c index c12d95f..abef2cb 100644 --- a/filesystems/fsw_ext4.c +++ b/filesystems/fsw_ext4.c @@ -72,6 +72,34 @@ struct fsw_fstype_table FSW_FSTYPE_TABLE_NAME(ext4) = { fsw_ext4_readlink, }; + +static inline int test_root(fsw_u32 a, int b) +{ + int num = b; + + while (a > num) + num *= b; + return num == a; +} + +static int fsw_ext4_group_sparse(fsw_u32 group) +{ + if (group <= 1) + return 1; + if (!(group & 1)) + return 0; + return (test_root(group, 7) || test_root(group, 5) || + test_root(group, 3)); +} + +/* calculate the first block number of the group */ +static inline fsw_u32 +fsw_ext4_group_first_block_no(struct ext4_super_block *sb, fsw_u32 group_no) +{ + return group_no * (fsw_u32)EXT4_BLOCKS_PER_GROUP(sb) + + sb->s_first_data_block; +} + /** * Mount an ext4 volume. Reads the superblock and constructs the * root directory dnode. @@ -82,7 +110,7 @@ static fsw_status_t fsw_ext4_volume_mount(struct fsw_ext4_volume *vol) fsw_status_t status; void *buffer; fsw_u32 blocksize; - fsw_u32 groupcnt, groupno, gdesc_per_block, gdesc_bno, gdesc_index; + fsw_u32 groupcnt, groupno, gdesc_per_block, gdesc_bno, gdesc_index, metabg_of_gdesc; struct ext4_group_desc *gdesc; int i; struct fsw_string s; @@ -111,7 +139,8 @@ static fsw_status_t fsw_ext4_volume_mount(struct fsw_ext4_volume *vol) if (vol->sb->s_rev_level == EXT4_DYNAMIC_REV && (vol->sb->s_feature_incompat & ~(EXT4_FEATURE_INCOMPAT_FILETYPE | EXT4_FEATURE_INCOMPAT_RECOVER | - EXT4_FEATURE_INCOMPAT_EXTENTS | EXT4_FEATURE_INCOMPAT_FLEX_BG))) + EXT4_FEATURE_INCOMPAT_EXTENTS | EXT4_FEATURE_INCOMPAT_FLEX_BG | + EXT4_FEATURE_INCOMPAT_META_BG))) return FSW_UNSUPPORTED; @@ -146,29 +175,53 @@ static fsw_status_t fsw_ext4_volume_mount(struct fsw_ext4_volume *vol) // size of group descriptor depends on feature.... if (!(vol->sb->s_feature_incompat & EXT4_FEATURE_INCOMPAT_64BIT)) { - // Default minimal group descriptor size... + // Default minimal group descriptor size... (this might not be set in old ext2 filesystems, therefor set it!) vol->sb->s_desc_size = EXT4_MIN_DESC_SIZE; } // Calculate group descriptor count the way the kernel does it... groupcnt = (vol->sb->s_blocks_count_lo - vol->sb->s_first_data_block + vol->sb->s_blocks_per_group - 1) / vol->sb->s_blocks_per_group; - // Descriptors in one block... s_desc_size needs to be set! + + // Descriptors in one block... s_desc_size needs to be set! (Usually 128 since normal block + // descriptors are 32 byte and block size is 4096) gdesc_per_block = EXT4_DESC_PER_BLOCK(vol->sb); // Read the group descriptors to get inode table offsets status = fsw_alloc(sizeof(fsw_u32) * groupcnt, &vol->inotab_bno); if (status) return status; + + // Loop through all block group descriptors in order to get inode table locations for (groupno = 0; groupno < groupcnt; groupno++) { - // get the block group descriptor - gdesc_bno = (vol->sb->s_first_data_block + 1) + groupno / gdesc_per_block; + + // Calculate the block number which contains the block group descriptor we look for + if(vol->sb->s_feature_incompat & EXT4_FEATURE_INCOMPAT_META_BG && groupno >= vol->sb->s_first_meta_bg) + { + // If option meta_bg is set, the block group descriptor is in meta block group... + metabg_of_gdesc = (fsw_u32)(groupno / gdesc_per_block) * gdesc_per_block; + gdesc_bno = fsw_ext4_group_first_block_no(vol->sb, metabg_of_gdesc); + // We need to know if the block group in questition has a super block, if yes, the + // block group descriptors are in the next block number + if(!(vol->sb->s_feature_ro_compat & EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER) || fsw_ext4_group_sparse(metabg_of_gdesc)) + gdesc_bno += 1; + } + else + { + // All group descriptors follow the super block (+1) + gdesc_bno = (vol->sb->s_first_data_block + 1) + groupno / gdesc_per_block; + } gdesc_index = groupno % gdesc_per_block; + + // Get block if necessary... status = fsw_block_get(vol, gdesc_bno, 1, (void **)&buffer); if (status) return status; + + // Get group descriptor table and block number of inode table... gdesc = (struct ext4_group_desc *)(buffer + gdesc_index * vol->sb->s_desc_size); vol->inotab_bno[groupno] = gdesc->bg_inode_table_lo; + fsw_block_release(vol, gdesc_bno, buffer); } @@ -332,9 +385,8 @@ static fsw_status_t fsw_ext4_get_by_extent(struct fsw_ext4_volume *vol, struct f struct fsw_extent *extent) { fsw_status_t status; - fsw_u32 bno, release_bno, buf_bcnt, buf_offset, file_bcnt; + fsw_u32 bno, release_bno, buf_offset, file_bcnt; int ext_cnt; - int ext_depth; void *buffer; struct ext4_extent_header *ext4_extent_header; @@ -346,7 +398,6 @@ static fsw_status_t fsw_ext4_get_by_extent(struct fsw_ext4_volume *vol, struct f // First buffer is the i_block field from inode... buffer = (void *)dno->raw->i_block; - buf_bcnt = EXT4_NDIR_BLOCKS; buf_offset = 0; while(1) { ext4_extent_header = (struct ext4_extent_header *)buffer + buf_offset; @@ -379,7 +430,7 @@ static fsw_status_t fsw_ext4_get_by_extent(struct fsw_ext4_volume *vol, struct f ext4_extent_header->eh_depth)); ext4_extent_idx = (struct ext4_extent_idx *)(buffer + buf_offset); buf_offset += sizeof(struct ext4_extent_idx); - + FSW_MSG_DEBUG((FSW_MSGSTR("fsw_ext4_get_by_extent: index node covers block %d...\n"), ext4_extent_idx->ei_block)); if(bno >= ext4_extent_idx->ei_block) @@ -394,7 +445,7 @@ static fsw_status_t fsw_ext4_get_by_extent(struct fsw_ext4_volume *vol, struct f } } } - + return FSW_NOT_FOUND; }