EXT2_BLOCK_SIZE_BITS
(offset >> EXT2_BLOCK_SIZE_BITS(inode->i_sb));
iblock = (offset + blocksize-1) >> EXT2_BLOCK_SIZE_BITS(inode->i_sb);
(offset >> EXT2_BLOCK_SIZE_BITS(sb));
sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);