From 93bca4c2a7c1852fc89df6965c835a7dbbdd6512 Mon Sep 17 00:00:00 2001 From: Lukas Oesch Date: Thu, 2 Apr 2026 09:50:14 +0200 Subject: read ext2 superblock and check the magic number --- kernel/src/filesystem/ext2/filesystem.cpp | 66 +++++++++++++++++-------------- 1 file changed, 37 insertions(+), 29 deletions(-) (limited to 'kernel/src/filesystem/ext2/filesystem.cpp') diff --git a/kernel/src/filesystem/ext2/filesystem.cpp b/kernel/src/filesystem/ext2/filesystem.cpp index eb9edc4..a3425b5 100644 --- a/kernel/src/filesystem/ext2/filesystem.cpp +++ b/kernel/src/filesystem/ext2/filesystem.cpp @@ -1,10 +1,10 @@ #include "kernel/filesystem/ext2/filesystem.hpp" -#include "kernel/devices/block_device_utils.hpp" #include "kapi/devices/device.hpp" + +#include "kernel/devices/block_device_utils.hpp" #include "kernel/filesystem/ext2/inode.hpp" #include "kernel/filesystem/ext2/superblock.hpp" -#include "kernel/filesystem/filesystem.hpp" #include "kernel/filesystem/inode.hpp" #include @@ -17,37 +17,35 @@ namespace kernel::filesystem::ext2 { namespace { - // constexpr size_t SUPERBLOCK_OFFSET = 1024; - // constexpr uint16_t EXT2_MAGIC = 0xEF53; - - // // Mode bits - // constexpr uint16_t S_IFMT = 0xF000; - // constexpr uint16_t S_IFREG = 0x8000; - // constexpr uint16_t S_IFDIR = 0x4000; - - // auto S_ISREG(uint16_t mode) -> bool - // { - // return (mode & S_IFMT) == S_IFREG; - // } - // auto S_ISDIR(uint16_t mode) -> bool - // { - // return (mode & S_IFMT) == S_IFDIR; - // } - - // auto get_block_size(superblock const & superblock) -> size_t - // { - // return 1024U << superblock.log_block_size; - // } - - // auto get_inode_size(superblock const & superblock) -> size_t - // { - // return superblock.rev_level == 0 ? 128 : superblock.inode_size; - // } + constexpr size_t SUPERBLOCK_OFFSET = 1024; + constexpr uint16_t EXT2_MAGIC = 0xEF53; + + // Mode bits + constexpr uint16_t S_IFMT = 0xF000; + constexpr uint16_t S_IFREG = 0x8000; + constexpr uint16_t S_IFDIR = 0x4000; + + auto S_ISREG(uint16_t mode) -> bool + { + return (mode & S_IFMT) == S_IFREG; + } + auto S_ISDIR(uint16_t mode) -> bool + { + return (mode & S_IFMT) == S_IFDIR; + } } // namespace auto filesystem::mount(kstd::shared_ptr const & device) -> int { - kernel::filesystem::filesystem::mount(device); // TODO BA-FS26 error handling? + m_device = device; + + kernel::devices::block_device_utils::read(m_device, &m_superblock, SUPERBLOCK_OFFSET, sizeof(m_superblock)); + + if (m_superblock.magic != EXT2_MAGIC) + { + return -1; + } + // TODO BA-FS26 load proper root inode from ext2 metadata // m_root_inode = inode{inode_kind::directory}; @@ -69,4 +67,14 @@ namespace kernel::filesystem::ext2 return kstd::make_shared(); } + + auto filesystem::get_block_size() -> size_t + { + return 1024U << m_superblock.log_block_size; + } + + auto filesystem::get_inode_size() -> size_t + { + return m_superblock.rev_level == 0 ? 128 : m_superblock.inode_size; + } } // namespace kernel::filesystem::ext2 -- cgit v1.2.3 From 1dcf253fdf8169a3b2b71bfac68f2f25951af1a8 Mon Sep 17 00:00:00 2001 From: Lukas Oesch Date: Thu, 2 Apr 2026 10:04:04 +0200 Subject: fix build, refactoring --- kernel/src/filesystem/ext2/filesystem.cpp | 27 ++++++++++++++------------- 1 file changed, 14 insertions(+), 13 deletions(-) (limited to 'kernel/src/filesystem/ext2/filesystem.cpp') diff --git a/kernel/src/filesystem/ext2/filesystem.cpp b/kernel/src/filesystem/ext2/filesystem.cpp index a3425b5..0ebb243 100644 --- a/kernel/src/filesystem/ext2/filesystem.cpp +++ b/kernel/src/filesystem/ext2/filesystem.cpp @@ -5,6 +5,7 @@ #include "kernel/devices/block_device_utils.hpp" #include "kernel/filesystem/ext2/inode.hpp" #include "kernel/filesystem/ext2/superblock.hpp" +#include "kernel/filesystem/filesystem.hpp" #include "kernel/filesystem/inode.hpp" #include @@ -21,23 +22,23 @@ namespace kernel::filesystem::ext2 constexpr uint16_t EXT2_MAGIC = 0xEF53; // Mode bits - constexpr uint16_t S_IFMT = 0xF000; - constexpr uint16_t S_IFREG = 0x8000; - constexpr uint16_t S_IFDIR = 0x4000; - - auto S_ISREG(uint16_t mode) -> bool - { - return (mode & S_IFMT) == S_IFREG; - } - auto S_ISDIR(uint16_t mode) -> bool - { - return (mode & S_IFMT) == S_IFDIR; - } + // constexpr uint16_t S_IFMT = 0xF000; + // constexpr uint16_t S_IFREG = 0x8000; + // constexpr uint16_t S_IFDIR = 0x4000; + + // auto S_ISREG(uint16_t mode) -> bool + // { + // return (mode & S_IFMT) == S_IFREG; + // } + // auto S_ISDIR(uint16_t mode) -> bool + // { + // return (mode & S_IFMT) == S_IFDIR; + // } } // namespace auto filesystem::mount(kstd::shared_ptr const & device) -> int { - m_device = device; + kernel::filesystem::filesystem::mount(device); kernel::devices::block_device_utils::read(m_device, &m_superblock, SUPERBLOCK_OFFSET, sizeof(m_superblock)); -- cgit v1.2.3 From 16b854e991bb791694268d09eb696c719cdff42f Mon Sep 17 00:00:00 2001 From: Lukas Oesch Date: Thu, 2 Apr 2026 11:09:13 +0200 Subject: read block_group_descriptors --- kernel/src/filesystem/ext2/filesystem.cpp | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'kernel/src/filesystem/ext2/filesystem.cpp') diff --git a/kernel/src/filesystem/ext2/filesystem.cpp b/kernel/src/filesystem/ext2/filesystem.cpp index 0ebb243..96c1589 100644 --- a/kernel/src/filesystem/ext2/filesystem.cpp +++ b/kernel/src/filesystem/ext2/filesystem.cpp @@ -3,12 +3,14 @@ #include "kapi/devices/device.hpp" #include "kernel/devices/block_device_utils.hpp" +#include "kernel/filesystem/ext2/block_group_descriptor.hpp" #include "kernel/filesystem/ext2/inode.hpp" #include "kernel/filesystem/ext2/superblock.hpp" #include "kernel/filesystem/filesystem.hpp" #include "kernel/filesystem/inode.hpp" #include +#include #include #include @@ -47,6 +49,17 @@ namespace kernel::filesystem::ext2 return -1; } + auto const block_size = get_block_size(); + auto const blocks_per_group = m_superblock.blocks_per_group; + auto const num_block_groups = (m_superblock.blocks_count + blocks_per_group - 1) / blocks_per_group; + + m_block_group_descriptors = kstd::vector(num_block_groups); + + auto const block_group_descriptor_table_offset = block_size == 1024 ? 2 * block_size : block_size; + kernel::devices::block_device_utils::read(m_device, m_block_group_descriptors.data(), + block_group_descriptor_table_offset, + num_block_groups * sizeof(block_group_descriptor)); + // TODO BA-FS26 load proper root inode from ext2 metadata // m_root_inode = inode{inode_kind::directory}; -- cgit v1.2.3 From baf63039d5430c0b3b1e6235b561c12f60e97f49 Mon Sep 17 00:00:00 2001 From: Lukas Oesch Date: Thu, 2 Apr 2026 15:03:06 +0200 Subject: implement read_inode --- kernel/src/filesystem/ext2/filesystem.cpp | 35 ++++++++++++++++++++++++------- 1 file changed, 27 insertions(+), 8 deletions(-) (limited to 'kernel/src/filesystem/ext2/filesystem.cpp') diff --git a/kernel/src/filesystem/ext2/filesystem.cpp b/kernel/src/filesystem/ext2/filesystem.cpp index 96c1589..d650e97 100644 --- a/kernel/src/filesystem/ext2/filesystem.cpp +++ b/kernel/src/filesystem/ext2/filesystem.cpp @@ -21,7 +21,9 @@ namespace kernel::filesystem::ext2 namespace { constexpr size_t SUPERBLOCK_OFFSET = 1024; - constexpr uint16_t EXT2_MAGIC = 0xEF53; + constexpr uint16_t MAGIC_NUMBER = 0xEF53; + + constexpr uint32_t ROOT_INODE_NUMBER = 2; // Mode bits // constexpr uint16_t S_IFMT = 0xF000; @@ -44,7 +46,7 @@ namespace kernel::filesystem::ext2 kernel::devices::block_device_utils::read(m_device, &m_superblock, SUPERBLOCK_OFFSET, sizeof(m_superblock)); - if (m_superblock.magic != EXT2_MAGIC) + if (m_superblock.magic != MAGIC_NUMBER) { return -1; } @@ -60,12 +62,7 @@ namespace kernel::filesystem::ext2 block_group_descriptor_table_offset, num_block_groups * sizeof(block_group_descriptor)); - // TODO BA-FS26 load proper root inode from ext2 metadata - // m_root_inode = inode{inode_kind::directory}; - - // TODO BA-FS26 implement - m_root_inode = kstd::make_shared(); - // devices::block_device_utils::read(device, nullptr, 0, 0); // TODO BA-FS26 just for testing + m_root_inode = read_inode(ROOT_INODE_NUMBER); return 0; } @@ -82,6 +79,28 @@ namespace kernel::filesystem::ext2 return kstd::make_shared(); } + auto filesystem::read_inode(uint32_t inode_number) -> kstd::shared_ptr + { + auto const block_size = get_block_size(); + auto const inodes_per_group = m_superblock.inodes_per_group; + auto const block_group_index = (inode_number - 1) / inodes_per_group; + auto const inode_index_within_group = (inode_number - 1) % inodes_per_group; + + if (block_group_index >= m_block_group_descriptors.size()) + { + return nullptr; + } + + auto const & block_group_descriptor = m_block_group_descriptors.at(block_group_index); + auto const inode_table_start_block = block_group_descriptor.inode_table; + auto const inode_table_offset = static_cast(inode_table_start_block) * block_size; + auto const inode_offset = inode_table_offset + inode_index_within_group * get_inode_size(); + + auto new_inode = kstd::make_shared(); + kernel::devices::block_device_utils::read(m_device, &new_inode->m_data, inode_offset, sizeof(inode_data)); + return new_inode; + } + auto filesystem::get_block_size() -> size_t { return 1024U << m_superblock.log_block_size; -- cgit v1.2.3 From 794de4a7f8dbea164d857ae9e4525536f338518d Mon Sep 17 00:00:00 2001 From: Lukas Oesch Date: Thu, 2 Apr 2026 16:06:40 +0200 Subject: temporary implementation of inode kind --- kernel/src/filesystem/ext2/filesystem.cpp | 41 ++++++++++++++++++++++--------- 1 file changed, 29 insertions(+), 12 deletions(-) (limited to 'kernel/src/filesystem/ext2/filesystem.cpp') diff --git a/kernel/src/filesystem/ext2/filesystem.cpp b/kernel/src/filesystem/ext2/filesystem.cpp index d650e97..31dc6f2 100644 --- a/kernel/src/filesystem/ext2/filesystem.cpp +++ b/kernel/src/filesystem/ext2/filesystem.cpp @@ -26,18 +26,18 @@ namespace kernel::filesystem::ext2 constexpr uint32_t ROOT_INODE_NUMBER = 2; // Mode bits - // constexpr uint16_t S_IFMT = 0xF000; - // constexpr uint16_t S_IFREG = 0x8000; - // constexpr uint16_t S_IFDIR = 0x4000; - - // auto S_ISREG(uint16_t mode) -> bool - // { - // return (mode & S_IFMT) == S_IFREG; - // } - // auto S_ISDIR(uint16_t mode) -> bool - // { - // return (mode & S_IFMT) == S_IFDIR; - // } + constexpr uint16_t S_IFMT = 0xF000; + constexpr uint16_t S_IFREG = 0x8000; + constexpr uint16_t S_IFDIR = 0x4000; + + auto S_ISREG(uint16_t mode) -> bool + { + return (mode & S_IFMT) == S_IFREG; + } + auto S_ISDIR(uint16_t mode) -> bool + { + return (mode & S_IFMT) == S_IFDIR; + } } // namespace auto filesystem::mount(kstd::shared_ptr const & device) -> int @@ -63,6 +63,7 @@ namespace kernel::filesystem::ext2 num_block_groups * sizeof(block_group_descriptor)); m_root_inode = read_inode(ROOT_INODE_NUMBER); + // TODO BA-FS26 check if root inode is valid and is a directory ?? return 0; } @@ -98,6 +99,22 @@ namespace kernel::filesystem::ext2 auto new_inode = kstd::make_shared(); kernel::devices::block_device_utils::read(m_device, &new_inode->m_data, inode_offset, sizeof(inode_data)); + + // TODO BA-FS26 improve inode_kind really needed? or just map it to the mode bits? + if (S_ISREG(new_inode->m_data.mode)) + { + new_inode->m_kind = inode::inode_kind::regular; + } + else if (S_ISDIR(new_inode->m_data.mode)) + { + new_inode->m_kind = inode::inode_kind::directory; + } + else + { + // TODO BA-FS26 really correct?? + return nullptr; + } + return new_inode; } -- cgit v1.2.3 From 82c8a4c16e3af3d62d7211e741b051da900de79c Mon Sep 17 00:00:00 2001 From: Lukas Oesch Date: Fri, 3 Apr 2026 10:16:36 +0200 Subject: first lookup draft --- kernel/src/filesystem/ext2/filesystem.cpp | 48 ++++++++++++++++++++++++++++++- 1 file changed, 47 insertions(+), 1 deletion(-) (limited to 'kernel/src/filesystem/ext2/filesystem.cpp') diff --git a/kernel/src/filesystem/ext2/filesystem.cpp b/kernel/src/filesystem/ext2/filesystem.cpp index 31dc6f2..82fcba9 100644 --- a/kernel/src/filesystem/ext2/filesystem.cpp +++ b/kernel/src/filesystem/ext2/filesystem.cpp @@ -5,11 +5,13 @@ #include "kernel/devices/block_device_utils.hpp" #include "kernel/filesystem/ext2/block_group_descriptor.hpp" #include "kernel/filesystem/ext2/inode.hpp" +#include "kernel/filesystem/ext2/linked_directory_entry.hpp" #include "kernel/filesystem/ext2/superblock.hpp" #include "kernel/filesystem/filesystem.hpp" #include "kernel/filesystem/inode.hpp" #include +#include #include #include @@ -24,6 +26,7 @@ namespace kernel::filesystem::ext2 constexpr uint16_t MAGIC_NUMBER = 0xEF53; constexpr uint32_t ROOT_INODE_NUMBER = 2; + constexpr size_t DIRECT_BLOCK_COUNT = 12; // Mode bits constexpr uint16_t S_IFMT = 0xF000; @@ -67,9 +70,52 @@ namespace kernel::filesystem::ext2 return 0; } - auto filesystem::lookup(kstd::shared_ptr const & /*parent*/, std::string_view name) + auto filesystem::lookup(kstd::shared_ptr const & parent, std::string_view name) -> kstd::shared_ptr { + if (!parent || !parent->is_directory()) + { + return nullptr; + } + + auto * ext2_parent = static_cast(parent.get()); + if (!ext2_parent) + { + return nullptr; + } + + auto const block_size = get_block_size(); + auto const & inode_data = ext2_parent->m_data; + kstd::vector buffer(block_size); + + for (size_t i = 0; i < DIRECT_BLOCK_COUNT && inode_data.block[i] != 0; ++i) + { + kernel::devices::block_device_utils::read(m_device, buffer.data(), inode_data.block[i] * block_size, block_size); + + size_t offset = 0; + while (offset < block_size) + { + auto * entry = reinterpret_cast(buffer.data() + offset); + if (entry->inode == 0) + break; + + // Stop if the directory entry is malformed to avoid overruns/loops. + // if (entry->rec_len < sizeof(linked_directory_entry) || offset + entry->rec_len > block_size) + // { + // break; + // } + + std::string_view entry_name(reinterpret_cast(entry->name.data()), entry->name_len); + if (entry_name == name) + { + return read_inode(entry->inode); + } + + offset += entry->rec_len; + } + } + + return nullptr; // TODO BA-FS26 implement ext2 directory traversal and inode loading if (name == "dev") { -- cgit v1.2.3 From 7e6137b2725d5cf2b16f55678dcfb99091f03fe9 Mon Sep 17 00:00:00 2001 From: Lukas Oesch Date: Fri, 3 Apr 2026 14:30:20 +0200 Subject: implement map_inode_block_index_to_global_block_number and lookup --- kernel/src/filesystem/ext2/filesystem.cpp | 120 ++++++++++++++++++++++++------ 1 file changed, 96 insertions(+), 24 deletions(-) (limited to 'kernel/src/filesystem/ext2/filesystem.cpp') diff --git a/kernel/src/filesystem/ext2/filesystem.cpp b/kernel/src/filesystem/ext2/filesystem.cpp index 82fcba9..a84414f 100644 --- a/kernel/src/filesystem/ext2/filesystem.cpp +++ b/kernel/src/filesystem/ext2/filesystem.cpp @@ -11,6 +11,7 @@ #include "kernel/filesystem/inode.hpp" #include +#include #include #include @@ -26,7 +27,11 @@ namespace kernel::filesystem::ext2 constexpr uint16_t MAGIC_NUMBER = 0xEF53; 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 TRIPLY_INDIRECT_BLOCK_INDEX = DOUBLY_INDIRECT_BLOCK_INDEX + 1; // Mode bits constexpr uint16_t S_IFMT = 0xF000; @@ -37,6 +42,7 @@ namespace kernel::filesystem::ext2 { return (mode & S_IFMT) == S_IFREG; } + auto S_ISDIR(uint16_t mode) -> bool { return (mode & S_IFMT) == S_IFDIR; @@ -88,42 +94,29 @@ namespace kernel::filesystem::ext2 auto const & inode_data = ext2_parent->m_data; kstd::vector buffer(block_size); - for (size_t i = 0; i < DIRECT_BLOCK_COUNT && inode_data.block[i] != 0; ++i) + for (uint32_t i = 0; i < get_inode_block_count(inode_data); ++i) { - kernel::devices::block_device_utils::read(m_device, buffer.data(), inode_data.block[i] * block_size, block_size); - - size_t offset = 0; - while (offset < block_size) - { - auto * entry = reinterpret_cast(buffer.data() + offset); - if (entry->inode == 0) - break; + auto const global_block_number = map_inode_block_index_to_global_block_number(i, inode_data); + auto const block_offset = global_block_number * block_size; + kernel::devices::block_device_utils::read(m_device, buffer.data(), block_offset, block_size); - // Stop if the directory entry is malformed to avoid overruns/loops. - // if (entry->rec_len < sizeof(linked_directory_entry) || offset + entry->rec_len > block_size) - // { - // break; - // } + auto const * entry = reinterpret_cast(buffer.data()); + auto bytes_read = 0uz; - std::string_view entry_name(reinterpret_cast(entry->name.data()), entry->name_len); + while (bytes_read < block_size && entry->inode != 0) + { + auto const entry_name = std::string_view{entry->name.data(), entry->name_len}; if (entry_name == name) { return read_inode(entry->inode); } - offset += entry->rec_len; + bytes_read += entry->rec_len; + entry = reinterpret_cast(buffer.data() + bytes_read); } } return nullptr; - // TODO BA-FS26 implement ext2 directory traversal and inode loading - if (name == "dev") - { - // TODO BA-FS26 just for testing - return nullptr; - } - - return kstd::make_shared(); } auto filesystem::read_inode(uint32_t inode_number) -> kstd::shared_ptr @@ -164,6 +157,80 @@ namespace kernel::filesystem::ext2 return new_inode; } + auto filesystem::map_inode_block_index_to_global_block_number(uint32_t inode_block_index, inode_data data) -> uint32_t + { + if (inode_block_index < DIRECT_BLOCK_COUNT) + { + return data.block.at(inode_block_index); + } + inode_block_index -= DIRECT_BLOCK_COUNT; + + 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 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; + } + inode_block_index -= number_of_singly_indirect_blocks; + + auto const number_of_doubly_indirect_blocks = numbers_per_block * numbers_per_block; + if (inode_block_index < number_of_doubly_indirect_blocks) + { + 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; + } + inode_block_index -= number_of_doubly_indirect_blocks; + + 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) + { + 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; + } + + return 0; // TODO BA-FS26 really correct?? + } + auto filesystem::get_block_size() -> size_t { return 1024U << m_superblock.log_block_size; @@ -173,4 +240,9 @@ namespace kernel::filesystem::ext2 { return m_superblock.rev_level == 0 ? 128 : m_superblock.inode_size; } + + auto filesystem::get_inode_block_count(inode_data const & data) -> uint32_t + { + return data.blocks / (2 << m_superblock.log_block_size); + } } // namespace kernel::filesystem::ext2 -- cgit v1.2.3 From fe8706422605e466427ae2727ddb98ce5cd984f6 Mon Sep 17 00:00:00 2001 From: Lukas Oesch Date: Fri, 3 Apr 2026 15:38:16 +0200 Subject: refactoring map_inode_block_index_to_global_block_number --- kernel/src/filesystem/ext2/filesystem.cpp | 101 ++++++++++++++---------------- 1 file changed, 48 insertions(+), 53 deletions(-) (limited to 'kernel/src/filesystem/ext2/filesystem.cpp') 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; -- cgit v1.2.3 From 725116d22e850c502e6cb8d42b100da1080dfec0 Mon Sep 17 00:00:00 2001 From: Marcel Braun Date: Mon, 6 Apr 2026 10:35:45 +0200 Subject: Add file system pointer to ext2 inode --- kernel/src/filesystem/ext2/filesystem.cpp | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/src/filesystem/ext2/filesystem.cpp') diff --git a/kernel/src/filesystem/ext2/filesystem.cpp b/kernel/src/filesystem/ext2/filesystem.cpp index 56c0b88..514bb59 100644 --- a/kernel/src/filesystem/ext2/filesystem.cpp +++ b/kernel/src/filesystem/ext2/filesystem.cpp @@ -136,7 +136,7 @@ namespace kernel::filesystem::ext2 auto const inode_table_offset = static_cast(inode_table_start_block) * block_size; auto const inode_offset = inode_table_offset + inode_index_within_group * get_inode_size(); - auto new_inode = kstd::make_shared(); + auto new_inode = kstd::make_shared(this); kernel::devices::block_device_utils::read(m_device, &new_inode->m_data, inode_offset, sizeof(inode_data)); // TODO BA-FS26 improve inode_kind really needed? or just map it to the mode bits? -- cgit v1.2.3 From 2240b9a36e4a9f6f8291c9271e6aac8f5536dbd7 Mon Sep 17 00:00:00 2001 From: Lukas Oesch Date: Tue, 7 Apr 2026 22:13:49 +0200 Subject: refactoring --- kernel/src/filesystem/ext2/filesystem.cpp | 2 -- 1 file changed, 2 deletions(-) (limited to 'kernel/src/filesystem/ext2/filesystem.cpp') diff --git a/kernel/src/filesystem/ext2/filesystem.cpp b/kernel/src/filesystem/ext2/filesystem.cpp index 514bb59..d7c989c 100644 --- a/kernel/src/filesystem/ext2/filesystem.cpp +++ b/kernel/src/filesystem/ext2/filesystem.cpp @@ -11,8 +11,6 @@ #include "kernel/filesystem/inode.hpp" #include -#include -#include #include #include -- cgit v1.2.3 From dd330e7a05905713acfa87ec109956bfe78f78c4 Mon Sep 17 00:00:00 2001 From: Lukas Oesch Date: Wed, 8 Apr 2026 09:31:32 +0200 Subject: add descriptions, some refactoring --- kernel/src/filesystem/ext2/filesystem.cpp | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) (limited to 'kernel/src/filesystem/ext2/filesystem.cpp') diff --git a/kernel/src/filesystem/ext2/filesystem.cpp b/kernel/src/filesystem/ext2/filesystem.cpp index d7c989c..7ee1072 100644 --- a/kernel/src/filesystem/ext2/filesystem.cpp +++ b/kernel/src/filesystem/ext2/filesystem.cpp @@ -36,6 +36,10 @@ namespace kernel::filesystem::ext2 constexpr uint16_t S_IFREG = 0x8000; constexpr uint16_t S_IFDIR = 0x4000; + // Error codes + constexpr int INVALID_MAGIC_NUMBER = -1; + constexpr int INVALID_ROOT_INODE = -2; + auto S_ISREG(uint16_t mode) -> bool { return (mode & S_IFMT) == S_IFREG; @@ -55,7 +59,7 @@ namespace kernel::filesystem::ext2 if (m_superblock.magic != MAGIC_NUMBER) { - return -1; + return INVALID_MAGIC_NUMBER; } auto const block_size = get_block_size(); @@ -70,7 +74,11 @@ namespace kernel::filesystem::ext2 num_block_groups * sizeof(block_group_descriptor)); m_root_inode = read_inode(ROOT_INODE_NUMBER); - // TODO BA-FS26 check if root inode is valid and is a directory ?? + + if (!m_root_inode || !m_root_inode->is_directory()) + { + return INVALID_ROOT_INODE; + } return 0; } -- cgit v1.2.3 From 2793770dc6eba30b73b4a4993618d2cbe184790e Mon Sep 17 00:00:00 2001 From: Lukas Oesch Date: Wed, 8 Apr 2026 15:21:10 +0200 Subject: implement unmount, improve error codes --- kernel/src/filesystem/ext2/filesystem.cpp | 12 ++++-------- 1 file changed, 4 insertions(+), 8 deletions(-) (limited to 'kernel/src/filesystem/ext2/filesystem.cpp') diff --git a/kernel/src/filesystem/ext2/filesystem.cpp b/kernel/src/filesystem/ext2/filesystem.cpp index 7ee1072..6d5960e 100644 --- a/kernel/src/filesystem/ext2/filesystem.cpp +++ b/kernel/src/filesystem/ext2/filesystem.cpp @@ -36,10 +36,6 @@ namespace kernel::filesystem::ext2 constexpr uint16_t S_IFREG = 0x8000; constexpr uint16_t S_IFDIR = 0x4000; - // Error codes - constexpr int INVALID_MAGIC_NUMBER = -1; - constexpr int INVALID_ROOT_INODE = -2; - auto S_ISREG(uint16_t mode) -> bool { return (mode & S_IFMT) == S_IFREG; @@ -51,7 +47,7 @@ namespace kernel::filesystem::ext2 } } // namespace - auto filesystem::mount(kstd::shared_ptr const & device) -> int + auto filesystem::mount(kstd::shared_ptr const & device) -> operation_result { kernel::filesystem::filesystem::mount(device); @@ -59,7 +55,7 @@ namespace kernel::filesystem::ext2 if (m_superblock.magic != MAGIC_NUMBER) { - return INVALID_MAGIC_NUMBER; + return operation_result::invalid_magic_number; } auto const block_size = get_block_size(); @@ -77,9 +73,9 @@ namespace kernel::filesystem::ext2 if (!m_root_inode || !m_root_inode->is_directory()) { - return INVALID_ROOT_INODE; + return operation_result::invalid_root_inode; } - return 0; + return operation_result::success; } auto filesystem::lookup(kstd::shared_ptr const & parent, std::string_view name) -- cgit v1.2.3 From 01d5f1b29fa04c69ac9f942a1075354ce5b25da2 Mon Sep 17 00:00:00 2001 From: Lukas Oesch Date: Thu, 9 Apr 2026 12:32:50 +0200 Subject: add ext2 inode and filesystem tests --- kernel/src/filesystem/ext2/filesystem.cpp | 38 ++++++++++--------------------- 1 file changed, 12 insertions(+), 26 deletions(-) (limited to 'kernel/src/filesystem/ext2/filesystem.cpp') diff --git a/kernel/src/filesystem/ext2/filesystem.cpp b/kernel/src/filesystem/ext2/filesystem.cpp index 6d5960e..0ad5c97 100644 --- a/kernel/src/filesystem/ext2/filesystem.cpp +++ b/kernel/src/filesystem/ext2/filesystem.cpp @@ -21,29 +21,14 @@ namespace kernel::filesystem::ext2 { namespace { - constexpr size_t SUPERBLOCK_OFFSET = 1024; - constexpr uint16_t MAGIC_NUMBER = 0xEF53; - - constexpr uint32_t ROOT_INODE_NUMBER = 2; - - constexpr size_t DIRECT_BLOCK_COUNT = 12; - 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 - constexpr uint16_t S_IFMT = 0xF000; - constexpr uint16_t S_IFREG = 0x8000; - constexpr uint16_t S_IFDIR = 0x4000; - auto S_ISREG(uint16_t mode) -> bool { - return (mode & S_IFMT) == S_IFREG; + return (mode & constants::mode_mask) == constants::mode_regular; } auto S_ISDIR(uint16_t mode) -> bool { - return (mode & S_IFMT) == S_IFDIR; + return (mode & constants::mode_mask) == constants::mode_directory; } } // namespace @@ -51,9 +36,10 @@ namespace kernel::filesystem::ext2 { kernel::filesystem::filesystem::mount(device); - kernel::devices::block_device_utils::read(m_device, &m_superblock, SUPERBLOCK_OFFSET, sizeof(m_superblock)); + kernel::devices::block_device_utils::read(m_device, &m_superblock, constants::superblock_offset, + sizeof(m_superblock)); - if (m_superblock.magic != MAGIC_NUMBER) + if (m_superblock.magic != constants::magic_number) { return operation_result::invalid_magic_number; } @@ -69,7 +55,7 @@ namespace kernel::filesystem::ext2 block_group_descriptor_table_offset, num_block_groups * sizeof(block_group_descriptor)); - m_root_inode = read_inode(ROOT_INODE_NUMBER); + m_root_inode = read_inode(constants::root_inode_number); if (!m_root_inode || !m_root_inode->is_directory()) { @@ -161,11 +147,11 @@ namespace kernel::filesystem::ext2 auto filesystem::map_inode_block_index_to_global_block_number(uint32_t inode_block_index, inode_data data) -> uint32_t { - if (inode_block_index < DIRECT_BLOCK_COUNT) + if (inode_block_index < constants::direct_block_count) { return data.block.at(inode_block_index); } - inode_block_index -= DIRECT_BLOCK_COUNT; + inode_block_index -= constants::direct_block_count; auto const block_size = get_block_size(); auto const numbers_per_block = block_size / sizeof(uint32_t); @@ -176,14 +162,14 @@ namespace kernel::filesystem::ext2 if (inode_block_index < block_numbers_per_singly_indirect_block) { - auto const singly_indirect_block_number = data.block.at(SINGLY_INDIRECT_BLOCK_INDEX); + 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); } inode_block_index -= block_numbers_per_singly_indirect_block; if (inode_block_index < block_numbers_per_doubly_indirect_block) { - auto const doubly_indirect_block_number = data.block.at(DOUBLY_INDIRECT_BLOCK_INDEX); + 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( @@ -196,7 +182,7 @@ namespace kernel::filesystem::ext2 if (inode_block_index < block_numbers_per_triply_indirect_block) { - auto const triply_indirect_block_number = data.block.at(TRIPLY_INDIRECT_BLOCK_INDEX); + 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( @@ -230,7 +216,7 @@ namespace kernel::filesystem::ext2 auto filesystem::get_block_size() -> size_t { - return 1024U << m_superblock.log_block_size; + return constants::base_block_size << m_superblock.log_block_size; } auto filesystem::get_inode_size() -> size_t -- cgit v1.2.3