diff options
Diffstat (limited to 'kernel/src/filesystem/ext2')
| -rw-r--r-- | kernel/src/filesystem/ext2/filesystem.cpp | 110 | ||||
| -rw-r--r-- | kernel/src/filesystem/ext2/filesystem.tests.cpp | 2 | ||||
| -rw-r--r-- | kernel/src/filesystem/ext2/inode.cpp | 22 | ||||
| -rw-r--r-- | kernel/src/filesystem/ext2/inode.tests.cpp | 101 |
4 files changed, 184 insertions, 51 deletions
diff --git a/kernel/src/filesystem/ext2/filesystem.cpp b/kernel/src/filesystem/ext2/filesystem.cpp index aaa50c7..893cc38 100644 --- a/kernel/src/filesystem/ext2/filesystem.cpp +++ b/kernel/src/filesystem/ext2/filesystem.cpp @@ -13,6 +13,7 @@ #include <cstddef> #include <cstdint> #include <string_view> +#include <unistd.h> namespace kernel::filesystem::ext2 { @@ -113,7 +114,7 @@ namespace kernel::filesystem::ext2 } auto filesystem::map_inode_block_index_to_global_block_number(uint32_t inode_block_index, inode_data data) const - -> uint32_t + -> ssize_t { if (inode_block_index < constants::direct_block_count) { @@ -121,54 +122,75 @@ namespace kernel::filesystem::ext2 } inode_block_index -= constants::direct_block_count; - auto const block_size = get_block_size(); - auto const numbers_per_block = block_size / sizeof(uint32_t); - - 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) + if (inode_block_index < block_numbers_per_singly_indirect_block()) { auto const singly_indirect_block_number = data.block.at(constants::singly_indirect_block_index); - return read_block_number_at_index(singly_indirect_block_number, inode_block_index); + return read_singly_indirect_block_number(singly_indirect_block_number, inode_block_index); } - inode_block_index -= block_numbers_per_singly_indirect_block; + inode_block_index -= block_numbers_per_singly_indirect_block(); - if (inode_block_index < block_numbers_per_doubly_indirect_block) + if (inode_block_index < block_numbers_per_doubly_indirect_block()) { auto const doubly_indirect_block_number = data.block.at(constants::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); + return read_doubly_indirect_block_number(doubly_indirect_block_number, inode_block_index); } - inode_block_index -= block_numbers_per_doubly_indirect_block; + inode_block_index -= block_numbers_per_doubly_indirect_block(); - if (inode_block_index < block_numbers_per_triply_indirect_block) + if (inode_block_index < block_numbers_per_triply_indirect_block()) { auto const triply_indirect_block_number = data.block.at(constants::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); + return read_triply_indirect_block_number(triply_indirect_block_number, inode_block_index); + } + + return -1; + } + + auto filesystem::read_singly_indirect_block_number(uint32_t singly_indirect_block_number, + uint32_t block_index_in_singly_indirect_block) const -> uint32_t + { + if (singly_indirect_block_number == 0) + { + return 0; + } + return read_block_number_at_index(singly_indirect_block_number, block_index_in_singly_indirect_block); + } + + auto filesystem::read_doubly_indirect_block_number(uint32_t doubly_indirect_block_number, + uint32_t block_index_in_doubly_indirect_block) const -> uint32_t + { + if (doubly_indirect_block_number == 0) + { + return 0; + } + + auto const singly_indirect_block_index_in_doubly_indirect_block = + block_index_in_doubly_indirect_block / block_numbers_per_singly_indirect_block(); + auto const block_index_in_singly_indirect_block = + block_index_in_doubly_indirect_block % block_numbers_per_singly_indirect_block(); - auto const remaining_block_numbers = inode_block_index % block_numbers_per_doubly_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 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); + return read_singly_indirect_block_number(singly_indirect_block_number, block_index_in_singly_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); + auto filesystem::read_triply_indirect_block_number(uint32_t triply_indirect_block_number, + uint32_t block_index_in_triply_indirect_block) const -> uint32_t + { + if (triply_indirect_block_number == 0) + { + return 0; } - return 0; // TODO BA-FS26 really correct?? + auto const doubly_indirect_block_index_in_triply_indirect_block = + block_index_in_triply_indirect_block / block_numbers_per_doubly_indirect_block(); + auto const block_index_in_doubly_indirect_block = + block_index_in_triply_indirect_block % 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); + + return read_doubly_indirect_block_number(doubly_indirect_block_number, block_index_in_doubly_indirect_block); } auto filesystem::read_block_number_at_index(uint32_t block_number, uint32_t index) const -> uint32_t @@ -182,6 +204,26 @@ namespace kernel::filesystem::ext2 return block_number_buffer; } + auto filesystem::block_numbers_per_block() const -> uint32_t + { + return get_block_size() / sizeof(uint32_t); + } + + auto filesystem::block_numbers_per_singly_indirect_block() const -> uint32_t + { + return block_numbers_per_block(); + } + + auto filesystem::block_numbers_per_doubly_indirect_block() const -> uint32_t + { + return block_numbers_per_singly_indirect_block() * block_numbers_per_block(); + } + + auto filesystem::block_numbers_per_triply_indirect_block() const -> uint32_t + { + return block_numbers_per_doubly_indirect_block() * block_numbers_per_block(); + } + auto filesystem::get_block_size() const -> size_t { return constants::base_block_size << m_superblock.log_block_size; diff --git a/kernel/src/filesystem/ext2/filesystem.tests.cpp b/kernel/src/filesystem/ext2/filesystem.tests.cpp index 31c4c29..8341070 100644 --- a/kernel/src/filesystem/ext2/filesystem.tests.cpp +++ b/kernel/src/filesystem/ext2/filesystem.tests.cpp @@ -133,7 +133,7 @@ SCENARIO("Ext2 block mapping includes direct and all indirect levels", "[filesys THEN("mapping returns zero for out-of-range indexes") { auto const beyond_triply = triply_start + numbers_per_block * numbers_per_block * numbers_per_block; - REQUIRE(fs.map_inode_block_index_to_global_block_number(beyond_triply, inode_data) == 0); + REQUIRE(fs.map_inode_block_index_to_global_block_number(beyond_triply, inode_data) == -1); } } } diff --git a/kernel/src/filesystem/ext2/inode.cpp b/kernel/src/filesystem/ext2/inode.cpp index 303838e..cfe0a35 100644 --- a/kernel/src/filesystem/ext2/inode.cpp +++ b/kernel/src/filesystem/ext2/inode.cpp @@ -40,23 +40,29 @@ namespace kernel::filesystem::ext2 auto bytes_read = 0uz; - while (bytes_read < size) + while (bytes_read < requested_size) { auto const block_number = m_filesystem->map_inode_block_index_to_global_block_number(block_index, m_data); - // TODO BA-FS26 really correct? sparse files -> 0 means a full block with zeros --> function - // map_inode_block_index_to_global_block_number should return 0 if not possible to find an block - if (block_number == 0) + if (block_number == -1) { break; } - auto const block_start_offset = block_number * m_filesystem->get_block_size(); - auto const read_offset = block_start_offset + in_block_offset; auto const bytes_to_read = std::min(requested_size - bytes_read, m_filesystem->get_block_size() - in_block_offset); + if (block_number == 0) + { + kstd::libc::memset(static_cast<uint8_t *>(buffer) + bytes_read, 0, bytes_to_read); + bytes_read += bytes_to_read; + } + else + { + auto const block_start_offset = block_number * m_filesystem->get_block_size(); + auto const read_offset = block_start_offset + in_block_offset; - bytes_read += - m_filesystem->backing_inode()->read(static_cast<uint8_t *>(buffer) + bytes_read, read_offset, bytes_to_read); + bytes_read += m_filesystem->backing_inode()->read(static_cast<uint8_t *>(buffer) + bytes_read, read_offset, + bytes_to_read); + } block_index++; in_block_offset = 0; // After the first block, we always start at the beginning of the block diff --git a/kernel/src/filesystem/ext2/inode.tests.cpp b/kernel/src/filesystem/ext2/inode.tests.cpp index 783d930..45bea51 100644 --- a/kernel/src/filesystem/ext2/inode.tests.cpp +++ b/kernel/src/filesystem/ext2/inode.tests.cpp @@ -15,6 +15,7 @@ #include <catch2/catch_test_macros.hpp> +#include <algorithm> #include <cstddef> #include <filesystem> #include <string_view> @@ -126,10 +127,10 @@ SCENARIO_METHOD(kernel::tests::filesystem::storage_boot_module_fixture, "Ext2 in } } -SCENARIO("Ext2 inode read stops when block mapping resolves to zero", "[filesystem][ext2][inode]") +SCENARIO("Ext2 inode handles zeros in block mappings as file holes", "[filesystem][ext2][inode]") { auto const block_size = 1024uz; - GIVEN("an ext2 inode without mapped data blocks") + GIVEN("an ext2 inode with only direct mapped data blocks") { auto device = kstd::make_shared<kernel::tests::devices::block_device>(0, 0, "mock", block_size, 64 * block_size); REQUIRE(device != nullptr); @@ -141,16 +142,100 @@ SCENARIO("Ext2 inode read stops when block mapping resolves to zero", "[filesyst REQUIRE(fs.mount(dev_inode) == kernel::filesystem::filesystem::operation_result::success); auto data = kernel::filesystem::ext2::inode_data{}; - data.blocks = 2; - data.block[0] = 0; + data.block[0] = 30; + data.block[1] = 0; + data.block[2] = 31; + data.size = block_size * 3; + + kernel::tests::filesystem::ext2::write_bytes(*device, 30 * block_size, "Hello", 5); + kernel::tests::filesystem::ext2::write_bytes(*device, 31 * block_size, "World!", 6); + + auto inode = kernel::filesystem::ext2::inode{&fs, data}; + + auto buffer = kstd::vector<std::byte>(data.size, std::byte{0xAB}); + + THEN("correct number of bytes are read and holes are returned as zeros") + { + auto const bytes_read = inode.read(buffer.data(), 0, buffer.size()); + REQUIRE(bytes_read == data.size); + + auto const text = std::string_view{reinterpret_cast<char const *>(buffer.data()), bytes_read}; + REQUIRE(text.substr(0, 5) == "Hello"); + REQUIRE(std::ranges::all_of(text.substr(5, block_size - 5), [](char c) { return c == '\0'; })); + REQUIRE(text.substr(2 * block_size, 6) == "World!"); + REQUIRE(std::ranges::all_of(text.substr(2 * block_size + 6, 3 * block_size), [](char c) { return c == '\0'; })); + } + } + + GIVEN("an ext2 indode with file holes in singly indirect blocks") + { + auto device = kstd::make_shared<kernel::tests::devices::block_device>(0, 0, "mock", block_size, 64 * block_size); + REQUIRE(device != nullptr); + kernel::tests::filesystem::ext2::setup_mock_ext2_layout(*device); + + auto dev_inode = kstd::make_shared<kernel::filesystem::device_inode>(device); + + auto fs = kernel::filesystem::ext2::filesystem{}; + REQUIRE(fs.mount(dev_inode) == kernel::filesystem::filesystem::operation_result::success); + + auto data = kernel::filesystem::ext2::inode_data{}; + data.block[0] = 30; + data.block[12] = 31; + data.size = block_size * 15; + + kernel::tests::filesystem::ext2::write_u32(*device, 31 * block_size, 50); + kernel::tests::filesystem::ext2::write_u32(*device, 31 * block_size + 4, 0); + kernel::tests::filesystem::ext2::write_u32(*device, 31 * block_size + 8, 51); + + kernel::tests::filesystem::ext2::write_bytes(*device, 30 * block_size, "Hello", 5); + kernel::tests::filesystem::ext2::write_bytes(*device, 50 * block_size, "Blub", 4); + kernel::tests::filesystem::ext2::write_bytes(*device, 51 * block_size, "World!", 6); + + auto inode = kernel::filesystem::ext2::inode{&fs, data}; + + auto buffer = kstd::vector<std::byte>(data.size, std::byte{0xAB}); + + THEN("correct number of bytes are read and holes are returned as zeros") + { + auto const bytes_read = inode.read(buffer.data(), 0, buffer.size()); + REQUIRE(bytes_read == data.size); + + auto const text = std::string_view{reinterpret_cast<char const *>(buffer.data()), bytes_read}; + REQUIRE(text.substr(0, 5) == "Hello"); + REQUIRE(std::ranges::all_of(text.substr(5, 12 * block_size - 5), [](char c) { return c == '\0'; })); + REQUIRE(text.substr(12 * block_size, 4) == "Blub"); + REQUIRE( + std::ranges::all_of(text.substr(12 * block_size + 4, 2 * block_size - 4), [](char c) { return c == '\0'; })); + REQUIRE(text.substr(14 * block_size, 6) == "World!"); + REQUIRE( + std::ranges::all_of(text.substr(14 * block_size + 6, 1 * block_size - 6), [](char c) { return c == '\0'; })); + } + } + + GIVEN("an ext2 inode with zero singly indirect block pointer") + { + auto device = kstd::make_shared<kernel::tests::devices::block_device>(0, 0, "mock", block_size, 64 * block_size); + REQUIRE(device != nullptr); + kernel::tests::filesystem::ext2::setup_mock_ext2_layout(*device); + + auto dev_inode = kstd::make_shared<kernel::filesystem::device_inode>(device); + + auto fs = kernel::filesystem::ext2::filesystem{}; + REQUIRE(fs.mount(dev_inode) == kernel::filesystem::filesystem::operation_result::success); + + auto data = kernel::filesystem::ext2::inode_data{}; + data.block[12] = 0; + data.size = block_size * 15; + auto inode = kernel::filesystem::ext2::inode{&fs, data}; - auto buffer = kstd::vector<std::byte>(32, std::byte{0xAB}); + auto buffer = kstd::vector<std::byte>(block_size * 15, std::byte{0xAB}); - THEN("no bytes are read") + THEN("all direct blocks are zero when singly indirect block pointer is zero") { auto const bytes_read = inode.read(buffer.data(), 0, buffer.size()); - REQUIRE(bytes_read == 0); + REQUIRE(bytes_read == buffer.size()); + REQUIRE(std::ranges::all_of(buffer, [](std::byte c) { return c == std::byte{0x00}; })); } } } @@ -170,7 +255,7 @@ SCENARIO("Ext2 inode read across block boundaries", "[filesystem][ext2][inode]") REQUIRE(fs.mount(dev_inode) == kernel::filesystem::filesystem::operation_result::success); auto inode_data = kernel::filesystem::ext2::inode_data{}; - inode_data.blocks = 2; + inode_data.size = block_size * 2; inode_data.block[0] = 20; kernel::tests::filesystem::ext2::write_bytes(*device, 21 * block_size - 6, "Hello ", 6); inode_data.block[1] = 21; |