From 84d4476650b31dbfc52becf2ff65ddce9d31c9ec Mon Sep 17 00:00:00 2001 From: Lukas Oesch Date: Tue, 24 Mar 2026 23:54:28 +0100 Subject: implement a rootfs to handle / mounts correctly --- kernel/CMakeLists.txt | 2 + kernel/include/kernel/filesystem/filesystem.hpp | 5 --- kernel/include/kernel/filesystem/mount.hpp | 10 +++-- .../kernel/filesystem/rootfs/rootfs_filesystem.hpp | 21 +++++++++++ .../kernel/filesystem/rootfs/rootfs_inode.hpp | 19 ++++++++++ kernel/src/filesystem/filesystem.cpp | 11 ------ kernel/src/filesystem/mount.cpp | 15 ++++++-- kernel/src/filesystem/mount_table.cpp | 14 ++----- kernel/src/filesystem/rootfs/rootfs_filesystem.cpp | 24 ++++++++++++ kernel/src/filesystem/rootfs/rootfs_inode.cpp | 22 +++++++++++ kernel/src/filesystem/vfs.cpp | 43 +++++++++++++++------- kernel/src/main.cpp | 10 +++++ 12 files changed, 149 insertions(+), 47 deletions(-) create mode 100644 kernel/include/kernel/filesystem/rootfs/rootfs_filesystem.hpp create mode 100644 kernel/include/kernel/filesystem/rootfs/rootfs_inode.hpp create mode 100644 kernel/src/filesystem/rootfs/rootfs_filesystem.cpp create mode 100644 kernel/src/filesystem/rootfs/rootfs_inode.cpp (limited to 'kernel') diff --git a/kernel/CMakeLists.txt b/kernel/CMakeLists.txt index ee1f585..406ac54 100644 --- a/kernel/CMakeLists.txt +++ b/kernel/CMakeLists.txt @@ -32,6 +32,8 @@ add_executable("kernel" "src/filesystem/mount_table.cpp" "src/filesystem/mount.cpp" "src/filesystem/open_file_description.cpp" + "src/filesystem/rootfs/rootfs_filesystem.cpp" + "src/filesystem/rootfs/rootfs_inode.cpp" "src/filesystem/vfs.cpp" ) diff --git a/kernel/include/kernel/filesystem/filesystem.hpp b/kernel/include/kernel/filesystem/filesystem.hpp index 362242f..e069ced 100644 --- a/kernel/include/kernel/filesystem/filesystem.hpp +++ b/kernel/include/kernel/filesystem/filesystem.hpp @@ -2,7 +2,6 @@ #define TEACH_OS_KERNEL_FILESYSTEM_FILESYSTEM_HPP #include "kernel/devices/device.hpp" -#include "kernel/filesystem/dentry.hpp" #include "kernel/filesystem/inode.hpp" #include @@ -20,15 +19,11 @@ namespace filesystem virtual auto lookup(kstd::shared_ptr const & parent, std::string_view name) -> kstd::shared_ptr = 0; [[nodiscard]] auto root_inode() const -> kstd::shared_ptr const &; - [[nodiscard]] auto root_dentry() const -> kstd::shared_ptr const &; - - auto set_root_dentry(kstd::shared_ptr dentry) -> void; protected: kstd::shared_ptr m_root_inode{}; kstd::shared_ptr m_device{}; kstd::vector> m_inodes{}; - kstd::shared_ptr m_root_dentry; }; } // namespace filesystem diff --git a/kernel/include/kernel/filesystem/mount.hpp b/kernel/include/kernel/filesystem/mount.hpp index dd47ce7..0cd30b4 100644 --- a/kernel/include/kernel/filesystem/mount.hpp +++ b/kernel/include/kernel/filesystem/mount.hpp @@ -10,13 +10,17 @@ namespace filesystem { struct mount { - mount(kstd::shared_ptr const & mount_dentry, kstd::shared_ptr const & fs); + mount(kstd::shared_ptr const & mount_dentry, kstd::shared_ptr const & root_dentry, + kstd::shared_ptr const & fs); + + [[nodiscard]] auto get_mount_dentry() const -> kstd::shared_ptr; + [[nodiscard]] auto root_dentry() const -> kstd::shared_ptr const &; - [[nodiscard]] auto get_dentry() const -> kstd::shared_ptr; [[nodiscard]] auto get_filesystem() const -> kstd::shared_ptr const &; private: - kstd::shared_ptr m_dentry; + kstd::shared_ptr m_mount_dentry; + kstd::shared_ptr m_root_dentry; kstd::shared_ptr m_filesystem{}; }; } // namespace filesystem diff --git a/kernel/include/kernel/filesystem/rootfs/rootfs_filesystem.hpp b/kernel/include/kernel/filesystem/rootfs/rootfs_filesystem.hpp new file mode 100644 index 0000000..949ac83 --- /dev/null +++ b/kernel/include/kernel/filesystem/rootfs/rootfs_filesystem.hpp @@ -0,0 +1,21 @@ +#ifndef TEACH_OS_KERNEL_FILESYSTEM_ROOTFS_ROOTFS_FILESYSTEM_HPP +#define TEACH_OS_KERNEL_FILESYSTEM_ROOTFS_ROOTFS_FILESYSTEM_HPP + +#include "kernel/devices/device.hpp" +#include "kernel/filesystem/filesystem.hpp" +#include "kernel/filesystem/inode.hpp" + +#include + +#include + +namespace filesystem::rootfs +{ + struct rootfs_filesystem : filesystem + { + auto mount(kstd::shared_ptr const & device) -> int override; + auto lookup(kstd::shared_ptr const & parent, std::string_view name) -> kstd::shared_ptr override; + }; +} // namespace filesystem::rootfs + +#endif diff --git a/kernel/include/kernel/filesystem/rootfs/rootfs_inode.hpp b/kernel/include/kernel/filesystem/rootfs/rootfs_inode.hpp new file mode 100644 index 0000000..d533e8e --- /dev/null +++ b/kernel/include/kernel/filesystem/rootfs/rootfs_inode.hpp @@ -0,0 +1,19 @@ +#ifndef TEACH_OS_KERNEL_FILESYSTEM_ROOTFS_ROOTFS_INODE_HPP +#define TEACH_OS_KERNEL_FILESYSTEM_ROOTFS_ROOTFS_INODE_HPP + +#include "kernel/filesystem/inode.hpp" + +#include + +namespace filesystem::rootfs +{ + struct rootfs_inode : inode + { + rootfs_inode(); + + auto read(void * buffer, size_t offset, size_t size) const -> size_t override; + auto write(void const * buffer, size_t offset, size_t size) -> size_t override; + }; +} // namespace filesystem::rootfs + +#endif diff --git a/kernel/src/filesystem/filesystem.cpp b/kernel/src/filesystem/filesystem.cpp index 8ebe58f..0e33d95 100644 --- a/kernel/src/filesystem/filesystem.cpp +++ b/kernel/src/filesystem/filesystem.cpp @@ -1,7 +1,6 @@ #include "kernel/filesystem/filesystem.hpp" #include "kernel/devices/device.hpp" -#include "kernel/filesystem/dentry.hpp" #include "kernel/filesystem/inode.hpp" #include @@ -22,14 +21,4 @@ namespace filesystem { return m_root_inode; } - - auto filesystem::root_dentry() const -> kstd::shared_ptr const & - { - return m_root_dentry; - } - - auto filesystem::set_root_dentry(kstd::shared_ptr dentry) -> void - { - m_root_dentry = dentry; - } } // namespace filesystem \ No newline at end of file diff --git a/kernel/src/filesystem/mount.cpp b/kernel/src/filesystem/mount.cpp index b65f331..d9937dc 100644 --- a/kernel/src/filesystem/mount.cpp +++ b/kernel/src/filesystem/mount.cpp @@ -11,8 +11,10 @@ namespace filesystem { - mount::mount(kstd::shared_ptr const & mount_dentry, kstd::shared_ptr const & fs) - : m_dentry(mount_dentry) + mount::mount(kstd::shared_ptr const & mount_dentry, kstd::shared_ptr const & root_dentry, + kstd::shared_ptr const & fs) + : m_mount_dentry(mount_dentry) + , m_root_dentry(root_dentry) , m_filesystem(fs) { if (!m_filesystem) @@ -21,13 +23,18 @@ namespace filesystem } } - auto mount::get_dentry() const -> kstd::shared_ptr + auto mount::get_mount_dentry() const -> kstd::shared_ptr { - return m_dentry; + return m_mount_dentry; } auto mount::get_filesystem() const -> kstd::shared_ptr const & { return m_filesystem; } + + auto mount::root_dentry() const -> kstd::shared_ptr const & + { + return m_root_dentry; + } } // namespace filesystem \ No newline at end of file diff --git a/kernel/src/filesystem/mount_table.cpp b/kernel/src/filesystem/mount_table.cpp index debb9ab..681c2b9 100644 --- a/kernel/src/filesystem/mount_table.cpp +++ b/kernel/src/filesystem/mount_table.cpp @@ -1,7 +1,5 @@ #include "kernel/filesystem/mount_table.hpp" -#include "kapi/system.hpp" - #include "kernel/filesystem/dentry.hpp" #include "kernel/filesystem/mount.hpp" @@ -18,18 +16,14 @@ namespace filesystem auto mount_table::get_root_mount() const -> kstd::shared_ptr { - auto it = - std::ranges::find_if(m_mounts, [](auto const & mount) { return mount->get_dentry()->get_parent() == nullptr; }); + auto it = std::ranges::find_if(m_mounts, [](auto const & mount) { return mount->get_mount_dentry() == nullptr; }); return it != m_mounts.end() ? *it : nullptr; } auto mount_table::find_mount_by_dentry(kstd::shared_ptr const & dentry) -> kstd::shared_ptr { - auto it = std::ranges::find_if(m_mounts, [&](auto const & mount) { return mount->get_dentry() == dentry; }); - if (it != m_mounts.end()) - { - return *it; - } - kapi::system::panic("[FILESYSTEM] dentry has mount flag set but no corresponding mount found."); + auto it = std::ranges::find_if(m_mounts, [&](auto const & mnt) { return mnt->get_mount_dentry() == dentry; }); + + return it != m_mounts.end() ? *it : nullptr; } } // namespace filesystem \ No newline at end of file diff --git a/kernel/src/filesystem/rootfs/rootfs_filesystem.cpp b/kernel/src/filesystem/rootfs/rootfs_filesystem.cpp new file mode 100644 index 0000000..22b1962 --- /dev/null +++ b/kernel/src/filesystem/rootfs/rootfs_filesystem.cpp @@ -0,0 +1,24 @@ +#include "kernel/filesystem/rootfs/rootfs_filesystem.hpp" + +#include "kernel/devices/device.hpp" +#include "kernel/filesystem/inode.hpp" +#include "kernel/filesystem/rootfs/rootfs_inode.hpp" + +#include + +#include + +namespace filesystem::rootfs +{ + auto rootfs_filesystem::mount(kstd::shared_ptr const & /*device*/) -> int + { + m_root_inode = kstd::make_shared(); + return 0; + } + + auto rootfs_filesystem::lookup(kstd::shared_ptr const & /*parent*/, std::string_view /*name*/) + -> kstd::shared_ptr + { + return nullptr; + } +} // namespace filesystem::rootfs diff --git a/kernel/src/filesystem/rootfs/rootfs_inode.cpp b/kernel/src/filesystem/rootfs/rootfs_inode.cpp new file mode 100644 index 0000000..ed057f7 --- /dev/null +++ b/kernel/src/filesystem/rootfs/rootfs_inode.cpp @@ -0,0 +1,22 @@ +#include "kernel/filesystem/rootfs/rootfs_inode.hpp" + +#include "kernel/filesystem/inode.hpp" + +#include + +namespace filesystem::rootfs +{ + rootfs_inode::rootfs_inode() + : inode(inode_kind::directory) + {} + + auto rootfs_inode::read(void * /*buffer*/, size_t /*offset*/, size_t /*size*/) const -> size_t + { + return 0; + } + + auto rootfs_inode::write(void const * /*buffer*/, size_t /*offset*/, size_t /*size*/) -> size_t + { + return 0; + } +} // namespace filesystem::rootfs diff --git a/kernel/src/filesystem/vfs.cpp b/kernel/src/filesystem/vfs.cpp index c8e5bc5..1c4dd8b 100644 --- a/kernel/src/filesystem/vfs.cpp +++ b/kernel/src/filesystem/vfs.cpp @@ -10,6 +10,7 @@ #include "kernel/filesystem/filesystem.hpp" #include "kernel/filesystem/mount.hpp" #include "kernel/filesystem/open_file_description.hpp" +#include "kernel/filesystem/rootfs/rootfs_filesystem.hpp" #include @@ -38,16 +39,20 @@ namespace filesystem auto vfs::init_internal() -> void { + auto virtual_fs = kstd::make_shared(); + virtual_fs->mount(nullptr); + + auto virtual_root_dentry = kstd::make_shared(nullptr, virtual_fs->root_inode(), "/"); + m_mount_table.add_mount(kstd::make_shared(nullptr, virtual_root_dentry, virtual_fs)); + auto storage_mgmt = devices::storage::storage_management::get(); if (auto boot_device = storage_mgmt.determine_boot_device()) { - auto root_fs = kstd::make_shared(); - root_fs->mount(boot_device); + // TODO BA-FS26 detect fs type from boot device and load corresponding fs, for now just assume ext2 + auto boot_root_fs = kstd::make_shared(); + boot_root_fs->mount(boot_device); - auto root_dentry = kstd::make_shared(nullptr, root_fs->root_inode(), "/"); - root_fs->set_root_dentry(root_dentry); - - m_mount_table.add_mount(kstd::make_shared(nullptr, root_fs)); + do_mount("/", boot_root_fs); // TODO BA-FS26 use do_mount when tempdevfs is implemented -> just call /dev/ with all devices in devtempfs std::ranges::for_each(storage_mgmt.all_controllers(), [&](auto controller) { @@ -102,10 +107,10 @@ namespace filesystem { // TODO BA-FS26 check if mount point is already mounted and handle it (unmount old fs, fail, etc.) + auto new_fs_root = kstd::make_shared(mount_dentry, filesystem->root_inode()); + auto new_mount = kstd::make_shared(mount_dentry, new_fs_root, filesystem); + m_mount_table.add_mount(new_mount); mount_dentry->set_flag(dentry::dentry_flags::dcache_mounted); - m_mount_table.add_mount(kstd::make_shared(mount_dentry, filesystem)); - - filesystem->set_root_dentry(kstd::make_shared(mount_dentry->get_parent(), filesystem->root_inode())); return 0; } @@ -153,20 +158,30 @@ namespace filesystem kapi::system::panic("[FILESYSTEM] no root mount found."); } - auto current_dentry = root_mount->get_dentry(); + auto current_dentry = root_mount->root_dentry(); auto current_fs = root_mount->get_filesystem(); + while (current_dentry->has_flag(dentry::dentry_flags::dcache_mounted)) + { + auto mnt = m_mount_table.find_mount_by_dentry(current_dentry); + if (!mnt) + kapi::system::panic("[FILESYSTEM] dcache_mounted set but no covering mount found."); + current_dentry = mnt->root_dentry(); + current_fs = mnt->get_filesystem(); + } + auto path_parts = std::views::split(path, '/') | std::views::filter([](auto const & part) { return !part.empty(); }); for (auto const & part : path_parts) { - auto next_dentry = current_dentry->find_child(std::string_view{part}); + std::string_view part_view{part}; + auto next_dentry = current_dentry->find_child(part_view); if (!next_dentry) { - if (auto found_inode = current_fs->lookup(current_dentry->get_inode(), std::string_view{part})) + if (auto found_inode = current_fs->lookup(current_dentry->get_inode(), part_view)) { - next_dentry = kstd::make_shared(current_dentry, found_inode, std::string_view{part}); + next_dentry = kstd::make_shared(current_dentry, found_inode, part_view); current_dentry->add_child(next_dentry); } else @@ -179,7 +194,7 @@ namespace filesystem { auto found_mount = m_mount_table.find_mount_by_dentry(next_dentry); current_fs = found_mount->get_filesystem(); - current_dentry = current_fs->root_dentry(); + current_dentry = found_mount->root_dentry(); } else { diff --git a/kernel/src/main.cpp b/kernel/src/main.cpp index 9571a0d..19a0992 100644 --- a/kernel/src/main.cpp +++ b/kernel/src/main.cpp @@ -5,6 +5,7 @@ #include "kernel/devices/storage/storage_management.hpp" #include "kernel/filesystem/device_inode.hpp" +#include "kernel/filesystem/ext2/ext2_filesystem.hpp" #include "kernel/filesystem/file_descriptor_table.hpp" #include "kernel/filesystem/open_file_description.hpp" #include "kernel/filesystem/vfs.hpp" @@ -108,8 +109,17 @@ auto test_file_lookup() -> void // TODO BA-FS26 implement a more complete test with multiple files and directories and mounts etc. auto vfs = filesystem::vfs::get(); + auto storage_mgmt = devices::storage::storage_management::get(); + vfs.open("/a/b/c"); vfs.open("/a/d/e"); + + auto new_filesystem = kstd::make_shared(); + auto device = storage_mgmt.device_by_major_minor(1, 16); + new_filesystem->mount(device); + vfs.do_mount("/a/b", new_filesystem); + vfs.open("/a/b/c"); + vfs.open("x/y/z"); } -- cgit v1.2.3