Changeset d76973c in mainline for uspace/lib/ext4/libext4_filesystem.c


Ignore:
Timestamp:
2015-04-25T21:20:11Z (10 years ago)
Author:
Maurizio Lombardi <m.lombardi85@…>
Branches:
lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export
Children:
60c409c
Parents:
7f29575
Message:

libext4: introduce support for flexible block groups.

With FLEX_BG, several block groups are tied together as one single group,
the first group of the flex_bg contains the block/inode bitmaps and the inode tables of all the other groups.
This improves metadata locality and frees up a lot of contiguous free space for extents.

  • modified ext4_balloc_free_blocks() so it can free extents spanning 2 or more block groups
  • with FLEX_BG the inode table, the bitmap and inode blocks of a group can reside on a different group.
    • the ext4_balloc_get_first_data_block_in_group() function has been modified to return a correct result in such a case.
    • improve the ext4_filesystem_init_block_bitmap() for the flex_bg case.
  • added the ext4_filesystem_blockaddr2group() function that given a block number returns the id of the group it belongs to.
  • added the ext4_filesystem_bg_get_itable_size() functions that given a group id number returns the size in blocks of its inode table.
File:
1 edited

Legend:

Unmodified
Added
Removed
  • uspace/lib/ext4/libext4_filesystem.c

    r7f29575 rd76973c  
    251251}
    252252
     253/** Convert the absolute block number to group number
     254 *
     255 * @param sb    Pointer to the superblock
     256 * @param b     Absolute block number
     257 *
     258 * @return      Group number
     259 */
     260uint32_t ext4_filesystem_blockaddr2group(ext4_superblock_t *sb, uint64_t b)
     261{
     262        uint32_t blocks_per_group = ext4_superblock_get_blocks_per_group(sb);
     263
     264        return b / blocks_per_group;
     265}
     266
    253267/** Initialize block bitmap in block group.
    254268 *
     
    260274static int ext4_filesystem_init_block_bitmap(ext4_block_group_ref_t *bg_ref)
    261275{
     276        uint64_t itb;
     277        uint32_t sz;
     278        uint32_t i;
     279
    262280        /* Load bitmap */
    263         uint32_t bitmap_block_addr = ext4_block_group_get_block_bitmap(
     281        ext4_superblock_t *sb = bg_ref->fs->superblock;
     282        uint64_t bitmap_block_addr = ext4_block_group_get_block_bitmap(
     283            bg_ref->block_group, bg_ref->fs->superblock);
     284        uint64_t bitmap_inode_addr = ext4_block_group_get_inode_bitmap(
    264285            bg_ref->block_group, bg_ref->fs->superblock);
    265286       
     
    273294       
    274295        /* Initialize all bitmap bits to zero */
    275         uint32_t block_size = ext4_superblock_get_block_size(bg_ref->fs->superblock);
     296        uint32_t block_size = ext4_superblock_get_block_size(sb);
    276297        memset(bitmap, 0, block_size);
    277298       
    278         /* Determine first block and first data block in group */
    279         uint32_t first_idx = 0;
    280        
    281         uint32_t first_data = ext4_balloc_get_first_data_block_in_group(
    282             bg_ref->fs->superblock, bg_ref);
    283         uint32_t first_data_idx = ext4_filesystem_blockaddr2_index_in_group(
    284             bg_ref->fs->superblock, first_data);
    285        
     299        /* Determine the number of reserved blocks in the group */
     300        uint32_t reserved_cnt = ext4_filesystem_bg_get_backup_blocks(bg_ref);
     301
    286302        /* Set bits from to first block to first data block - 1 to one (allocated) */
    287         for (uint32_t block = first_idx; block < first_data_idx; ++block)
     303        for (uint32_t block = 0; block < reserved_cnt; ++block)
    288304                ext4_bitmap_set_bit(bitmap, block);
    289        
     305
     306        uint32_t bitmap_block_gid = ext4_filesystem_blockaddr2group(sb,
     307            bitmap_block_addr);
     308        if (bitmap_block_gid == bg_ref->index) {
     309                ext4_bitmap_set_bit(bitmap,
     310                    ext4_filesystem_blockaddr2_index_in_group(sb, bitmap_block_addr));
     311        }
     312
     313        uint32_t bitmap_inode_gid = ext4_filesystem_blockaddr2group(sb,
     314            bitmap_inode_addr);
     315        if (bitmap_inode_gid == bg_ref->index) {
     316                ext4_bitmap_set_bit(bitmap,
     317                    ext4_filesystem_blockaddr2_index_in_group(sb, bitmap_inode_addr));
     318        }
     319
     320        itb = ext4_block_group_get_inode_table_first_block(bg_ref->block_group,
     321            sb);
     322        sz = ext4_filesystem_bg_get_itable_size(sb, bg_ref);
     323
     324        for (i = 0; i < sz; ++i, ++itb) {
     325                uint32_t gid = ext4_filesystem_blockaddr2group(sb, itb);
     326                if (gid == bg_ref->index) {
     327                        ext4_bitmap_set_bit(bitmap,
     328                            ext4_filesystem_blockaddr2_index_in_group(sb, itb));
     329                }
     330        }
     331
    290332        bitmap_block->dirty = true;
    291333       
     
    524566}
    525567
     568/** Get the size of the block group's inode table
     569 *
     570 * @param sb     Pointer to the superblock
     571 * @param bg_ref Pointer to the block group reference
     572 *
     573 * @return       Size of the inode table in blocks.
     574 */
     575uint32_t ext4_filesystem_bg_get_itable_size(ext4_superblock_t *sb,
     576    ext4_block_group_ref_t *bg_ref)
     577{
     578        uint32_t itable_size;
     579        uint32_t block_group_count = ext4_superblock_get_block_group_count(sb);
     580        uint16_t inode_table_item_size = ext4_superblock_get_inode_size(sb);
     581        uint32_t inodes_per_group = ext4_superblock_get_inodes_per_group(sb);
     582        uint32_t block_size = ext4_superblock_get_block_size(sb);
     583
     584        if (bg_ref->index < block_group_count - 1) {
     585                itable_size = inodes_per_group * inode_table_item_size;
     586        } else {
     587                /* Last block group could be smaller */
     588                uint32_t inodes_count_total = ext4_superblock_get_inodes_count(sb);
     589                itable_size =
     590                    (inodes_count_total - ((block_group_count - 1) * inodes_per_group)) *
     591                    inode_table_item_size;
     592        }
     593
     594        return ROUND_UP(itable_size, block_size) / block_size;
     595}
     596
    526597/* Check if n is a power of p */
    527598static bool is_power_of(uint32_t n, unsigned p)
     
    548619 * @return      Number of blocks
    549620 */
    550 uint32_t ext4_block_group_get_backup_blocks(ext4_block_group_ref_t *bg)
     621uint32_t ext4_filesystem_bg_get_backup_blocks(ext4_block_group_ref_t *bg)
    551622{
    552623        uint32_t const idx = bg->index;
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