diff options
| -rw-r--r-- | kernel/include/kernel/filesystem/ext2/filesystem.hpp | 1 | ||||
| -rw-r--r-- | kernel/src/filesystem/ext2/filesystem.cpp | 101 |
2 files changed, 49 insertions, 53 deletions
diff --git a/kernel/include/kernel/filesystem/ext2/filesystem.hpp b/kernel/include/kernel/filesystem/ext2/filesystem.hpp index dea059f..9761903 100644 --- a/kernel/include/kernel/filesystem/ext2/filesystem.hpp +++ b/kernel/include/kernel/filesystem/ext2/filesystem.hpp @@ -27,6 +27,7 @@ namespace kernel::filesystem::ext2 private: auto read_inode(uint32_t inode_number) -> kstd::shared_ptr<kernel::filesystem::ext2::inode>; auto map_inode_block_index_to_global_block_number(uint32_t inode_block_index, inode_data data) -> uint32_t; + auto read_block_number_at_index(uint32_t block_number, uint32_t index) -> uint32_t; auto get_block_size() -> size_t; auto get_inode_size() -> size_t; diff --git a/kernel/src/filesystem/ext2/filesystem.cpp b/kernel/src/filesystem/ext2/filesystem.cpp index a84414f..56c0b88 100644 --- a/kernel/src/filesystem/ext2/filesystem.cpp +++ b/kernel/src/filesystem/ext2/filesystem.cpp @@ -29,8 +29,8 @@ namespace kernel::filesystem::ext2 constexpr uint32_t ROOT_INODE_NUMBER = 2; constexpr size_t DIRECT_BLOCK_COUNT = 12; - constexpr size_t INDIRECT_BLOCK_INDEX = DIRECT_BLOCK_COUNT; - constexpr size_t DOUBLY_INDIRECT_BLOCK_INDEX = INDIRECT_BLOCK_INDEX + 1; + constexpr size_t SINGLY_INDIRECT_BLOCK_INDEX = DIRECT_BLOCK_COUNT; + constexpr size_t DOUBLY_INDIRECT_BLOCK_INDEX = SINGLY_INDIRECT_BLOCK_INDEX + 1; constexpr size_t TRIPLY_INDIRECT_BLOCK_INDEX = DOUBLY_INDIRECT_BLOCK_INDEX + 1; // Mode bits @@ -167,70 +167,65 @@ namespace kernel::filesystem::ext2 auto const block_size = get_block_size(); auto const numbers_per_block = block_size / sizeof(uint32_t); - uint32_t block_number_buffer = 0; - auto const number_of_singly_indirect_blocks = numbers_per_block; - if (inode_block_index < number_of_singly_indirect_blocks) + auto const block_numbers_per_singly_indirect_block = numbers_per_block; + auto const block_numbers_per_doubly_indirect_block = numbers_per_block * block_numbers_per_singly_indirect_block; + auto const block_numbers_per_triply_indirect_block = numbers_per_block * block_numbers_per_doubly_indirect_block; + + if (inode_block_index < block_numbers_per_singly_indirect_block) { - auto const indirect_block_start_offset = data.block.at(INDIRECT_BLOCK_INDEX) * block_size; - auto const direct_block_number_index = inode_block_index; - auto const direct_block_number_offset = - indirect_block_start_offset + direct_block_number_index * sizeof(uint32_t); - kernel::devices::block_device_utils::read(m_device, &block_number_buffer, direct_block_number_offset, - sizeof(uint32_t)); - return block_number_buffer; + auto const singly_indirect_block_number = data.block.at(SINGLY_INDIRECT_BLOCK_INDEX); + return read_block_number_at_index(singly_indirect_block_number, inode_block_index); } - inode_block_index -= number_of_singly_indirect_blocks; + inode_block_index -= block_numbers_per_singly_indirect_block; - auto const number_of_doubly_indirect_blocks = numbers_per_block * numbers_per_block; - if (inode_block_index < number_of_doubly_indirect_blocks) + if (inode_block_index < block_numbers_per_doubly_indirect_block) { - auto const doubly_indirect_block_start_offset = data.block.at(DOUBLY_INDIRECT_BLOCK_INDEX) * block_size; - auto const indirect_block_number_index = inode_block_index / numbers_per_block; - auto const indirect_block_number_offset = - doubly_indirect_block_start_offset + indirect_block_number_index * sizeof(uint32_t); - kernel::devices::block_device_utils::read(m_device, &block_number_buffer, indirect_block_number_offset, - sizeof(uint32_t)); - - auto const indirect_block_start_offset = block_number_buffer * block_size; - auto const direct_block_number_index = inode_block_index % numbers_per_block; - auto const direct_block_number_offset = - indirect_block_start_offset + direct_block_number_index * sizeof(uint32_t); - kernel::devices::block_device_utils::read(m_device, &block_number_buffer, direct_block_number_offset, - sizeof(uint32_t)); - return block_number_buffer; + auto const doubly_indirect_block_number = data.block.at(DOUBLY_INDIRECT_BLOCK_INDEX); + auto const singly_indirect_block_index_in_doubly_indirect_block = + inode_block_index / block_numbers_per_singly_indirect_block; + auto const singly_indirect_block_number = read_block_number_at_index( + doubly_indirect_block_number, singly_indirect_block_index_in_doubly_indirect_block); + + auto const block_index_in_singly_indirect_block = inode_block_index % block_numbers_per_singly_indirect_block; + return read_block_number_at_index(singly_indirect_block_number, block_index_in_singly_indirect_block); } - inode_block_index -= number_of_doubly_indirect_blocks; + inode_block_index -= block_numbers_per_doubly_indirect_block; - auto const number_of_triply_indirect_blocks = numbers_per_block * numbers_per_block * numbers_per_block; - if (inode_block_index < number_of_triply_indirect_blocks) + if (inode_block_index < block_numbers_per_triply_indirect_block) { - auto const triply_indirect_block_start_offset = data.block.at(TRIPLY_INDIRECT_BLOCK_INDEX) * block_size; - auto const doubly_indirect_block_number_index = inode_block_index / (numbers_per_block * numbers_per_block); - auto const doubly_indirect_block_number_offset = - triply_indirect_block_start_offset + doubly_indirect_block_number_index * sizeof(uint32_t); - kernel::devices::block_device_utils::read(m_device, &block_number_buffer, doubly_indirect_block_number_offset, - sizeof(uint32_t)); - - auto const doubly_indirect_block_start_offset = block_number_buffer * block_size; - auto const indirect_block_number_index = (inode_block_index / numbers_per_block) % numbers_per_block; - auto const indirect_block_number_offset = - doubly_indirect_block_start_offset + indirect_block_number_index * sizeof(uint32_t); - kernel::devices::block_device_utils::read(m_device, &block_number_buffer, indirect_block_number_offset, - sizeof(uint32_t)); - - auto const indirect_block_start_offset = block_number_buffer * block_size; - auto const direct_block_number_index = inode_block_index % numbers_per_block; - auto const direct_block_number_offset = - indirect_block_start_offset + direct_block_number_index * sizeof(uint32_t); - kernel::devices::block_device_utils::read(m_device, &block_number_buffer, direct_block_number_offset, - sizeof(uint32_t)); - return block_number_buffer; + auto const triply_indirect_block_number = data.block.at(TRIPLY_INDIRECT_BLOCK_INDEX); + auto const doubly_indirect_block_index_in_triply_indirect_block = + inode_block_index / block_numbers_per_doubly_indirect_block; + auto const doubly_indirect_block_number = read_block_number_at_index( + triply_indirect_block_number, doubly_indirect_block_index_in_triply_indirect_block); + + auto const remaining_block_numbers = inode_block_index % block_numbers_per_doubly_indirect_block; + + auto const singly_indirect_block_index_in_doubly_indirect_block = + remaining_block_numbers / block_numbers_per_singly_indirect_block; + auto const singly_indirect_block_number = read_block_number_at_index( + doubly_indirect_block_number, singly_indirect_block_index_in_doubly_indirect_block); + + auto const block_index_in_singly_indirect_block = + remaining_block_numbers % block_numbers_per_singly_indirect_block; + return read_block_number_at_index(singly_indirect_block_number, block_index_in_singly_indirect_block); } return 0; // TODO BA-FS26 really correct?? } + auto filesystem::read_block_number_at_index(uint32_t block_number, uint32_t index) -> uint32_t + { + uint32_t block_number_buffer = 0; + + auto const block_start_offset = block_number * get_block_size(); + auto const number_start_address = block_start_offset + index * sizeof(uint32_t); + kernel::devices::block_device_utils::read(m_device, &block_number_buffer, number_start_address, sizeof(uint32_t)); + + return block_number_buffer; + } + auto filesystem::get_block_size() -> size_t { return 1024U << m_superblock.log_block_size; |