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rewrite fs

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sfja 2026-03-05 00:29:29 +01:00
parent a0df6785ef
commit d42b6e00d1
3 changed files with 389 additions and 368 deletions
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479
src/fs.cpp
View File

@ -1,10 +1,12 @@
#include "fs.hpp" #include "fs.hpp"
#include "block_device.hpp"
#include <cassert> #include <cassert>
#include <cstdint> #include <concepts>
#include <cstring> #include <cstring>
#include <optional> #include <optional>
#include <string_view> #include <string_view>
#include <tuple> #include <tuple>
#include <utility>
namespace vc5::filesys { namespace vc5::filesys {
@ -13,16 +15,10 @@ namespace {
auto inode_mode(INodeType type) -> u16 auto inode_mode(INodeType type) -> u16
{ {
u16 mode = 0; u16 mode = 0;
mode |= std::to_underlying(type) << inode_type_bitoffset; mode |= std::to_underlying(type) << INode::type_bitoffset;
return mode; return mode;
} }
auto inode_mode_type(u16 mode) -> INodeType
{
return static_cast<INodeType>(
mode >> inode_type_bitoffset & inode_type_bitmask);
}
auto unwrap_inode_id(u16 inode_id) -> std::tuple<u16, u16> auto unwrap_inode_id(u16 inode_id) -> std::tuple<u16, u16>
{ {
u16 inode_block_idx = inode_id / inodes_per_block; u16 inode_block_idx = inode_id / inodes_per_block;
@ -37,234 +33,244 @@ namespace {
} }
auto Fs::init_new(u16 volume_id, u16 block_count) -> Result<void> auto Fs::init(u16 volume_id, u16 block_count) -> void
{ {
m_superblock = Superblock { m_superblock = Superblock {
.volume_id = volume_id, .volume_id = volume_id,
.fs_version = 1, .fs_version = 1,
.blocks_count = block_count, .blocks_count = 0,
.blocks_free = block_count, .blocks_free = block_count,
.root_inode = 0, .root_inode = 0,
.inode_blocks_count = 0, .inode_blocks_count = 0,
.iblocks = {}, .inode_blocks = {},
.inode_bitmap = {}, .inode_bitmap = {},
}; };
auto root_inode_id = make_directory_inode(); m_blocks_bitmap = {};
if (not root_inode_id) m_blocks_bitmap.bitmap[0] = true;
return std::unexpected(root_inode_id.error()); m_blocks_bitmap.bitmap[1] = true;
m_blocks_bitmap.bitmap[sb_loc] = true;
m_blocks_bitmap.bitmap[blocks_bitmap_loc] = true;
m_superblock.root_inode = *root_inode_id; auto root_inode_id = allocate_inode();
auto root_inode = make_dir_with_inode_ids(root_inode_id, root_inode_id);
(void)root_inode;
if (auto result = sync_to_disk(); not result) m_superblock.root_inode = root_inode_id;
return result;
return {}; m_out_of_sync = true;
sync_to_disk();
} }
auto Fs::init_from_existing() -> Result<void> auto Fs::load() -> void
{ {
return sync_from_disk(); m_superblock = read_block<Superblock>(sb_loc);
m_blocks_bitmap = read_block<BlocksBitmap>(blocks_bitmap_loc);
m_out_of_sync = false;
} }
auto Fs::make_file(u16 parent_inode_id, std::string_view name) -> Result<u16> auto Fs::root_inode() -> INode
{ {
return make_inode(parent_inode_id, name, INodeType::Dir); return read_inode(m_superblock.root_inode);
} }
auto Fs::make_directory(u16 parent_inode_id, std::string_view name) auto Fs::make_dir(INode& parent, std::string_view name) -> INode
-> Result<u16> {
auto inode_id = allocate_inode();
auto inode = make_dir_with_inode_ids(inode_id, parent.id);
write_inode(inode);
add_inode_to_dir(parent, inode, name);
sync_to_disk();
return inode;
}
auto Fs::make_file(INode& parent, std::string_view name) -> INode
{ {
return make_inode(parent_inode_id, name, INodeType::Dir);
}
// auto Fs::write(u16 inode_id, const void* data, u16 size) -> Result<u16>
// {
// auto inode_result = read_inode(inode_id);
// if (not inode_result)
// return std::unexpected(inode_result.error());
// auto& inode = *inode_result;
//
// if (auto result = inode_for_each_block_id(inode,
// [&](u16& block_id) {
// deallocate_block(block_id);
// block_id = 0;
// });
// not result)
// return std::unexpected(result.error());
// }
auto Fs::make_inode(u16 parent_inode_id, std::string_view name, INodeType type)
-> Result<u16>
{
if (name.size() > name_max_len)
return std::unexpected("invalid filename");
auto inode_id = allocate_inode(); auto inode_id = allocate_inode();
if (not inode_id)
return inode_id;
auto inode = INode { auto inode = INode {
.mode = inode_mode(type), .id = inode_id,
.mode = inode_mode(INodeType::File),
.blocks_count = 0, .blocks_count = 0,
.links_count = 0, .links_count = 0,
.last_block_size = 0,
.size = 0, .size = 0,
.last_block_size = 0,
.blocks = {}, .blocks = {},
}; };
write_inode(inode);
add_inode_to_dir(parent, inode, name);
sync_to_disk();
return inode;
}
template <typename Func>
requires ReturnsControlFlow<Func, u16>
auto Fs::inode_foreach_block(INode& inode, Func func) -> void
{
using ControlFlow::Break;
for (u16 i = 0; i < inode.blocks_count && i < INode::ndir_blocks; ++i) {
if (func(inode.blocks[i]) == Break) {
return;
}
}
auto block_id = inode.blocks[INode::ind_block];
assert(block_id != 0);
auto ind_block = read_block<IndirectionBlock>(block_id);
for (u16 i = 0; i < inode.blocks_count - INode::ndir_blocks; ++i) {
if (func(ind_block.values[i]) == Break) {
return;
}
}
}
void Fs::add_inode_to_dir(INode& dir, const INode& inode, std::string_view name)
{
if (not dir.is_dir()) {
throw FsError("incorrect inode type");
}
if (name.size() > 256) {
throw FsError("invalid argument");
}
auto entry = DirEntry { auto entry = DirEntry {
.inode = *inode_id, .inode = inode.id,
.next = 0, .next = 0,
.name_len = static_cast<u16>(name.size()), .name_len = static_cast<u16>(name.size()),
.name = {}, .name = {},
}; };
std::memcpy(entry.name.data(), name.data(), name.size()); std::memcpy(entry.name.data(), name.data(), name.size());
write_dir_entry(dir, entry);
if (auto result = append_to_directory(parent_inode_id, entry); not result) write_inode(dir);
return std::unexpected(result.error());
if (auto result = write_inode(*inode_id, inode); not result)
return std::unexpected(result.error());
return inode_id;
} }
auto Fs::append_to_directory(u16 dir_inode_id, const DirEntry& entry) auto Fs::make_dir_with_inode_ids(u16 inode_id, u16 parent_inode_id) -> INode
-> Result<void>
{ {
auto dir_inode_result = read_inode(dir_inode_id);
if (not dir_inode_result)
return std::unexpected(dir_inode_result.error());
auto& dir_inode = *dir_inode_result;
if (inode_mode_type(dir_inode.mode) != INodeType::Dir)
return std::unexpected("incorrect inode type");
if (dir_inode.blocks_count == inode_last_block
&& entry.size() > block_size - dir_inode.last_block_size) {
return std::unexpected("inode at capacity");
}
auto last_block_id = inode_last_block_id(dir_inode);
if (not last_block_id)
return std::unexpected(last_block_id.error());
if (auto result = write_block_part(
*last_block_id, entry, dir_inode.last_block_size, entry.size());
not result)
return std::unexpected(result.error());
dir_inode.last_block_size += entry.size();
if (auto result = write_inode(dir_inode_id, dir_inode); not result)
return std::unexpected(result.error());
return {};
}
auto Fs::make_directory_inode() -> Result<u16>
{
auto inode_id = allocate_inode();
if (not inode_id)
return inode_id;
auto inode = INode { auto inode = INode {
.id = inode_id,
.mode = inode_mode(INodeType::Dir), .mode = inode_mode(INodeType::Dir),
.blocks_count = 0, .blocks_count = 0,
.links_count = 0, .links_count = 0,
.last_block_size = 0,
.size = 0, .size = 0,
.last_block_size = 0,
.blocks = {}, .blocks = {},
}; };
write_inode(inode);
if (auto result = write_inode(*inode_id, inode); not result) auto parent_name = std::string_view("..");
return std::unexpected(result.error()); auto parent_entry = DirEntry {
.inode = parent_inode_id,
return inode_id; .next = 0,
} .name_len = static_cast<u16>(parent_name.size()),
.name = {},
auto Fs::inode_last_block_id(const INode& inode) -> Result<u16>
{
if (inode.blocks_count < inode_ndir_blocks) {
return inode.blocks_count - 1;
} else if (inode.blocks_count >= inode_ind_block
&& inode.blocks_count <= inode_ind_block + block_size) {
auto block_id = inode.blocks[inode_ind_block];
assert(block_id != 0);
auto ind_block = read_block<IntBlock<u16>>(block_id);
if (not ind_block)
return std::unexpected(ind_block.error());
return ind_block->data[inode.blocks_count - inode_ind_block];
} else {
return std::unexpected("invalid inode");
}
}
template <typename Func>
auto Fs::inode_for_each_block_id(const INode& inode, Func func) -> Result<void>
{
for (u16 i = 0; i < inode.blocks_count && i < inode_ndir_blocks; ++i) {
func(inode.blocks[i]);
}
auto block_id = inode.blocks[inode_ind_block];
assert(block_id != 0);
auto ind_block = read_block<IntBlock<u16>>(block_id);
if (not ind_block)
return std::unexpected(ind_block.error());
for (u16 i = 0; i < inode.blocks_count - inode_ndir_blocks; ++i) {
func(inode.blocks[i]);
}
}
auto Fs::read_inode(u16 inode_id) -> Result<INode>
{
auto [inode_block_idx, block_offset] = unwrap_inode_id(inode_id);
if (inode_block_idx >= m_superblock.inode_blocks_count)
return std::unexpected("inode lookup failed");
auto block_id = m_superblock.iblocks[inode_block_idx];
struct INodeData {
u16 mode;
u16 blocks_count;
u16 links_count;
u16 last_block_size;
u32 size;
std::array<u16, inode_blocks_count> blocks;
}; };
static_assert(sizeof(INodeData) == sizeof(INode)); std::memcpy(
parent_entry.name.data(), parent_name.data(), parent_name.size());
write_dir_entry(inode, parent_entry);
return read_block_part<INode>(block_id, block_offset); return inode;
} }
auto Fs::write_inode(u16 inode_id, const INode& inode) -> Result<void> auto Fs::write_dir_entry(INode& dir_inode, const DirEntry& entry) -> void
{
u16 entry_block_id;
bool new_block = false;
if (dir_inode.last_block_size + entry.size() > block_size) {
entry_block_id = inode_allocate_block(dir_inode);
new_block = true;
} else {
entry_block_id = inode_last_block(dir_inode);
}
auto entry_block = read_block<DirEntryBlock>(entry_block_id);
if (not new_block) {
u16 offset = 0;
DirEntry entry;
do {
entry = entry_block.read_entry(offset);
if (entry.next != 0) {
offset = entry.next;
}
} while (entry.next != 0);
u16 new_offset = offset + static_cast<u16>(entry.size());
entry.next = new_offset;
entry_block.write_entry(offset, entry);
entry_block.write_entry(new_offset, entry);
} else {
entry_block.write_entry(0, entry);
}
write_block(entry_block_id, entry_block);
}
auto Fs::inode_allocate_block(INode& inode) -> u16
{
auto block_id = allocate_block();
inode.blocks[inode.blocks_count] = block_id;
inode.blocks_count++;
return block_id;
}
auto Fs::inode_last_block(INode& inode) -> u16
{
if (inode.blocks_count == 0) {
auto block_id = allocate_block();
inode.blocks[0] = block_id;
inode.blocks_count += 1;
return block_id;
}
if (inode.blocks_count < INode::ndir_blocks) {
return inode.blocks[inode.blocks_count - 1];
}
if (inode.blocks_count >= INode::ind_block
&& inode.blocks_count - INode::ind_block < block_size) {
auto ind_block_id = inode.blocks[INode::ind_block];
assert(ind_block_id != 0);
auto ind_block = read_block<IndirectionBlock>(ind_block_id);
return ind_block.values[inode.blocks_count - INode::ind_block];
}
throw FsError("invalid inode");
}
auto Fs::read_inode(u16 inode_id) -> INode
{ {
auto [inode_block_idx, block_offset] = unwrap_inode_id(inode_id); auto [inode_block_idx, block_offset] = unwrap_inode_id(inode_id);
if (inode_block_idx >= m_superblock.inode_blocks_count) if (inode_block_idx >= m_superblock.inode_blocks_count)
return std::unexpected("inode lookup failed"); throw FsError("inode lookup failed");
auto block_id = m_superblock.iblocks[inode_block_idx]; auto block_id = m_superblock.inode_blocks[inode_block_idx];
if (auto result = write_block_part(block_id, inode, block_offset); return read_block<INode>(block_id, block_offset);
not result)
return result;
return {};
} }
auto Fs::allocate_inode() -> Result<u16> auto Fs::write_inode(const INode& inode) -> void
{
auto [inode_block_idx, block_offset] = unwrap_inode_id(inode.id);
if (inode_block_idx >= m_superblock.inode_blocks_count)
throw FsError("inode lookup failed");
auto block_id = m_superblock.inode_blocks[inode_block_idx];
write_block(block_id, inode, block_offset);
}
auto Fs::allocate_inode() -> u16
{ {
auto inode_id = std::optional<u16>(); auto inode_id = std::optional<u16>();
auto& sb = m_superblock; auto& sb = m_superblock;
@ -277,22 +283,22 @@ auto Fs::allocate_inode() -> Result<u16>
if (not inode_id) { if (not inode_id) {
if (sb.inode_blocks_count >= iblocks_max_count) { if (sb.inode_blocks_count >= iblocks_max_count) {
return std::unexpected("inode allocate failed"); throw FsError("inode allocate failed");
} }
auto new_block_id = allocate_block(); auto new_block_id = allocate_block();
if (not new_block_id)
return new_block_id;
sb.iblocks[sb.inode_blocks_count] = *new_block_id; sb.inode_blocks[sb.inode_blocks_count] = new_block_id;
inode_id = sb.inode_blocks_count * 16; inode_id = sb.inode_blocks_count * 16;
sb.inode_blocks_count += 1; sb.inode_blocks_count += 1;
} }
sb.inode_bitmap[*inode_id] = true; sb.inode_bitmap[*inode_id] = true;
m_out_of_sync = true;
return *inode_id; return *inode_id;
} }
auto Fs::allocate_block() -> Result<u16> auto Fs::allocate_block() -> u16
{ {
u16 block_id = 0; u16 block_id = 0;
@ -304,43 +310,27 @@ auto Fs::allocate_block() -> Result<u16>
} }
} }
if (block_id == 0) { if (block_id == 0) {
return std::unexpected("allocate block failed"); throw FsError("allocate block failed");
} }
m_blocks_bitmap.bitmap[block_id] = true; m_blocks_bitmap.bitmap[block_id] = true;
m_out_of_sync = true;
return block_id; return block_id;
} }
void Fs::deallocate_block(u16 block_id) void Fs::deallocate_block(u16 block_id)
{ {
m_blocks_bitmap.bitmap[block_id] = false; m_blocks_bitmap.bitmap[block_id] = false;
m_out_of_sync = true;
} }
auto Fs::sync_from_disk() -> Result<void> auto Fs::sync_to_disk() -> void
{ {
auto superblock = read_block<Superblock>(sb_loc); if (m_out_of_sync) {
if (not superblock) write_block(sb_loc, m_superblock);
return std::unexpected(superblock.error()); write_block(blocks_bitmap_loc, m_blocks_bitmap);
m_out_of_sync = false;
auto blocks_bitmap = read_block<BlocksBitmap>(blocks_bitmap_loc);
if (not blocks_bitmap)
return std::unexpected(superblock.error());
m_superblock = *superblock;
m_blocks_bitmap = *blocks_bitmap;
return {};
} }
auto Fs::sync_to_disk() -> Result<void>
{
if (auto result = write_block(m_superblock, sb_loc); not result)
return result;
if (auto result = write_block(m_blocks_bitmap, blocks_bitmap_loc);
not result)
return result;
return {};
} }
class BeWriter { class BeWriter {
@ -430,21 +420,31 @@ private:
const u8* m_data; const u8* m_data;
}; };
using BlockData = std::array<u8, block_size>; using RawBlock = std::array<uint8_t, block_size>;
template <typename Data> template <typename Data>
requires(sizeof(Data) <= block_size) requires(sizeof(Data) <= block_size)
auto Fs::read_block_part(u16 block_id, u16 offset, u16 size) -> Result<Data> auto Fs::write_block(u16 block_id, const Data& data, size_t offset) -> void
{ {
assert(size + offset <= block_size); assert(sizeof(Data) + offset <= block_size);
auto block = BlockData {}; auto block = RawBlock {};
m_disk->read(block.data(), block_id); m_disk->read(block.data(), block_id);
auto raw_data = BlockData {}; auto writer = BeWriter(block.data() + offset);
std::memcpy(raw_data.data(), block.data() + offset, size); data.write(writer);
auto reader = BeReader(raw_data.data()); m_disk->write(block.data(), block_id);
}
template <typename Data>
requires(sizeof(Data) <= block_size)
auto Fs::read_block(u16 block_id, size_t offset) -> Data
{
auto block = RawBlock {};
m_disk->read(block.data(), block_id);
auto reader = BeReader(block.data() + offset);
Data data; Data data;
data.read(reader); data.read(reader);
@ -452,54 +452,35 @@ auto Fs::read_block_part(u16 block_id, u16 offset, u16 size) -> Result<Data>
return data; return data;
} }
template <typename Data> void Fs::write_block_raw(
requires(sizeof(Data) <= block_size) u16 block_id, const void* data, size_t size, size_t offset)
auto Fs::write_block_part(u16 block_id, const Data& data, u16 offset, u16 size)
-> Result<void>
{ {
assert(size + offset <= block_size); assert(size + offset <= BlockDevice::block_size);
auto raw_data = BlockData {}; if (size == BlockDevice::block_size && offset == 0) {
return m_disk->write(static_cast<const u8*>(data), block_id);
}
auto writer = BeWriter(raw_data.data()); auto block = RawBlock {};
data.write(writer);
auto block = BlockData {};
m_disk->read(block.data(), block_id); m_disk->read(block.data(), block_id);
std::memcpy(block.data() + offset, raw_data.data(), size); std::memcpy(block.data() + offset, data, size);
m_disk->write(block.data(), block_id); m_disk->write(block.data(), block_id);
return {};
} }
template <typename Data> void Fs::read_block_raw(void* data, size_t size, u16 block_id, size_t offset)
requires(sizeof(Data) <= block_size)
auto Fs::read_block(u16 block_id) -> Result<Data>
{ {
auto block = BlockData {}; assert(size + offset <= BlockDevice::block_size);
if (size == BlockDevice::block_size && offset == 0) {
return m_disk->read(static_cast<u8*>(data), block_id);
}
auto block = RawBlock {};
m_disk->read(block.data(), block_id); m_disk->read(block.data(), block_id);
auto reader = BeReader(block.data()); std::memcpy(data, block.data() + offset, size);
Data data;
data.read(reader);
return data;
}
template <typename Data>
requires(sizeof(Data) <= block_size)
auto Fs::write_block(const Data& data, u16 block_id) -> Result<void>
{
auto block = BlockData {};
auto writer = BeWriter(block.data());
data.write(writer);
m_disk->write(block.data(), block_id);
return {};
} }
} }

255
src/fs.hpp
View File

@ -3,42 +3,18 @@
#include "block_device.hpp" #include "block_device.hpp"
#include "types.hpp" #include "types.hpp"
#include <bitset> #include <bitset>
#include <cassert>
#include <concepts> #include <concepts>
#include <cstddef> #include <cstddef>
#include <expected> #include <cstring>
#include <stdexcept>
#include <string_view> #include <string_view>
#include <type_traits> #include <type_traits>
#include <utility>
namespace vc5::filesys { namespace vc5::filesys {
constexpr u16 block_size = 0x200; constexpr u16 block_size = 0x200;
constexpr u16 name_max_len = 256;
struct DirEntry {
u16 inode;
u16 next;
u16 name_len;
std::array<char, name_max_len> name;
template <typename Writer> void write(Writer& w) const
{
w << inode << next << name_len << name;
}
template <typename Reader> auto read(Reader& r)
{
r >> inode >> next >> name_len >> name;
}
auto size() const -> u16
{
return sizeof(inode) + sizeof(next) + sizeof(name_len)
+ sizeof(char) * name_len;
}
};
constexpr u16 inode_size = 32; constexpr u16 inode_size = 32;
constexpr u16 inodes_per_block = block_size / inode_size; constexpr u16 inodes_per_block = block_size / inode_size;
@ -48,22 +24,23 @@ enum class INodeType : u16 {
Link = 2, Link = 2,
}; };
constexpr u16 inode_type_bitoffset = 0;
constexpr u16 inode_type_bitmask = 0b11;
constexpr u16 inode_ndir_blocks = 9;
constexpr u16 inode_ind_block = inode_ndir_blocks;
constexpr u16 inode_blocks_count = inode_ind_block + 1;
constexpr u16 inode_last_block = inode_ndir_blocks + block_size;
struct INode { struct INode {
static constexpr u16 type_bitoffset = 0;
static constexpr u16 type_bitmask = 0b11;
static constexpr u16 ndir_blocks = 8;
static constexpr u16 ind_block = ndir_blocks;
static constexpr u16 max_blocks_count = ind_block + 1;
static constexpr u16 inode_last_block = ndir_blocks + block_size;
u16 id;
u16 mode; u16 mode;
u16 blocks_count; u16 blocks_count;
u16 links_count; u16 links_count;
u16 last_block_size;
u32 size; u32 size;
std::array<u16, inode_blocks_count> blocks; u16 last_block_size;
std::array<u16, max_blocks_count> blocks;
template <typename Writer> void write(Writer& w) const template <typename Writer> void write(Writer& w) const
{ {
@ -71,11 +48,23 @@ struct INode {
<< blocks; << blocks;
} }
template <typename Reader> auto read(Reader& r) template <typename Reader> void read(Reader& r)
{ {
r >> mode >> blocks_count >> links_count >> last_block_size >> size r >> mode >> blocks_count >> links_count >> last_block_size >> size
>> blocks; >> blocks;
} }
auto is_file() const -> bool
{
return static_cast<INodeType>(mode >> type_bitoffset & type_bitmask)
== INodeType::File;
}
auto is_dir() const -> bool
{
return static_cast<INodeType>(mode >> type_bitoffset & type_bitmask)
== INodeType::Dir;
}
}; };
static_assert(sizeof(INode) <= inode_size); static_assert(sizeof(INode) <= inode_size);
@ -93,19 +82,19 @@ struct Superblock {
u16 blocks_free; u16 blocks_free;
u16 root_inode; u16 root_inode;
u16 inode_blocks_count; u16 inode_blocks_count;
std::array<u16, iblocks_max_count> iblocks; std::array<u16, iblocks_max_count> inode_blocks;
std::bitset<inodes_max_count> inode_bitmap; std::bitset<inodes_max_count> inode_bitmap;
template <typename Writer> void write(Writer& w) const template <typename Writer> void write(Writer& w) const
{ {
w << volume_id << fs_version << blocks_count << blocks_free w << volume_id << fs_version << blocks_count << blocks_free
<< root_inode << inode_blocks_count << iblocks << inode_bitmap; << root_inode << inode_blocks_count << inode_blocks << inode_bitmap;
} }
template <typename Reader> auto read(Reader& r) template <typename Reader> void read(Reader& r)
{ {
r >> volume_id >> fs_version >> blocks_count >> blocks_free r >> volume_id >> fs_version >> blocks_count >> blocks_free
>> root_inode >> inode_blocks_count >> iblocks >> inode_bitmap; >> root_inode >> inode_blocks_count >> inode_blocks >> inode_bitmap;
} }
}; };
@ -119,29 +108,107 @@ struct BlocksBitmap {
w << bitmap; w << bitmap;
} }
template <typename Reader> auto read(Reader& r) template <typename Reader> void read(Reader& r)
{ {
r >> bitmap; r >> bitmap;
} }
}; };
static_assert(sizeof(BlocksBitmap) <= block_size);
template <typename Int> struct DirEntry {
requires std::is_integral_v<Int> static constexpr u16 name_max_len = 256;
struct IntBlock {
std::array<u16, block_size / sizeof(Int)> data; u16 inode;
u16 next;
u16 name_len;
std::array<char, name_max_len> name;
template <typename Writer> void write(Writer& w) const
{
w << inode << next << name_len;
for (int i = 0; i < name_len; ++i) {
w << name[i];
}
}
template <typename Reader> void read(Reader& r)
{
r >> inode >> next >> name_len;
for (int i = 0; i < name_len; ++i) {
r << name[i];
}
}
auto size() const -> u16
{
return sizeof(inode) + sizeof(next) + sizeof(name_len)
+ sizeof(char) * name_len;
}
};
struct IndirectionBlock {
std::array<u16, block_size / sizeof(u16)> values;
template <typename Reader> void read(Reader& r)
{
r >> values;
}
template <typename Writer> void write(Writer& w) const
{
w << values;
}
};
struct DirEntryBlock {
std::array<uint8_t, block_size> data;
template <typename Reader> void read(Reader& r)
{
r >> data;
}
template <typename Writer> void write(Writer& w) const template <typename Writer> void write(Writer& w) const
{ {
w << data; w << data;
} }
template <typename Reader> auto read(Reader& r) inline DirEntry read_entry(u16 offset)
{ {
r >> data; // it's ok to read into the entire entry
DirEntry entry;
std::memcpy(&entry,
data.data() + offset,
std::min<size_t>(sizeof(DirEntry), block_size - offset));
assert(entry.size() + offset <= block_size);
return entry;
}
inline void write_entry(u16 offset, const DirEntry& entry)
{
assert(entry.size() + offset <= block_size);
std::memcpy(data.data() + offset, &entry, entry.size());
} }
}; };
static_assert(sizeof(BlocksBitmap) <= block_size); enum class ControlFlow {
Continue,
Break,
};
template <typename Func, typename... Args>
concept ReturnsControlFlow
= std::invocable<Func, Args...> && requires(Func func, Args... args) {
{ func(args...) } -> std::convertible_to<ControlFlow>;
};
class FsError : public std::runtime_error {
using std::runtime_error::runtime_error;
};
class Fs { class Fs {
public: public:
@ -149,85 +216,55 @@ public:
: m_disk(&disk) : m_disk(&disk)
{ {
} }
auto init(u16 volume_id, u16 block_count) -> void;
auto load() -> void;
template <typename T> using Result = std::expected<T, std::string_view>; auto root_inode() -> INode;
auto make_dir(INode& parent, std::string_view name) -> INode;
auto make_file(INode& parent, std::string_view name) -> INode;
static auto init_new(BlockDevice& disk, u16 volume_id, u16 block_count) auto write(u16 inode_id, const void* data, u16 size) -> u16;
-> Result<Fs>
{
auto fs = Fs(disk);
if (auto result = fs.init_new(volume_id, block_count); not result)
return std::unexpected(result.error());
return fs;
}
static auto load(BlockDevice& disk) -> Result<Fs>
{
auto fs = Fs(disk);
if (auto result = fs.init_from_existing(); not result)
return std::unexpected(result.error());
return fs;
}
auto root_inode_id() const -> Result<u16>
{
return m_superblock.root_inode;
}
auto make_file(u16 parent_inode_id, std::string_view name) -> Result<u16>;
auto make_directory(u16 parent_inode_id, std::string_view name)
-> Result<u16>;
auto write(u16 inode_id, const void* data, u16 size) -> Result<u16>;
private: private:
auto init_new(u16 volume_id, u16 block_count) -> Result<void>;
auto init_from_existing() -> Result<void>;
auto make_inode(u16 parent_inode_id, std::string_view name, INodeType type)
-> Result<u16>;
auto append_to_directory(u16 dir_inode_id, const DirEntry& entry)
-> Result<void>;
auto make_directory_inode() -> Result<u16>;
auto inode_last_block_id(const INode& inode) -> Result<u16>;
template <typename Func> template <typename Func>
auto inode_for_each_block_id(const INode& inode, Func func) -> Result<void>; requires ReturnsControlFlow<Func, u16>
auto inode_foreach_block(INode& inode, Func func) -> void;
auto write_inode(u16 inode_id, const INode& inode) -> Result<void>; void add_inode_to_dir(
auto read_inode(u16 inode_id) -> Result<INode>; INode& dir, const INode& inode, std::string_view name);
auto allocate_inode() -> Result<u16>; auto make_dir_with_inode_ids(u16 inode_id, u16 parent_inode_id) -> INode;
auto write_dir_entry(INode& dir_inode, const DirEntry& entry) -> void;
auto inode_allocate_block(INode& inode) -> u16;
auto inode_last_block(INode& inode) -> u16;
auto allocate_block() -> Result<u16>; auto write_inode(const INode& inode) -> void;
auto read_inode(u16 inode_id) -> INode;
auto allocate_inode() -> u16;
auto allocate_block() -> u16;
void deallocate_block(u16 block_id); void deallocate_block(u16 block_id);
auto sync_from_disk() -> Result<void>; auto sync_to_disk() -> void;
auto sync_to_disk() -> Result<void>;
// templates declared here to get private access // templates declared here to get private access
template <typename Data> template <typename Data>
requires(sizeof(Data) <= block_size) requires(sizeof(Data) <= block_size)
auto read_block_part(u16 block_id, u16 offset, u16 size = sizeof(Data)) auto write_block(u16 block_id, const Data& data, size_t offset = 0) -> void;
-> Result<Data>;
template <typename Data> template <typename Data>
requires(sizeof(Data) <= block_size) requires(sizeof(Data) <= block_size)
auto write_block_part( auto read_block(u16 block_id, size_t offset = 0) -> Data;
u16 block_id, const Data& data, u16 offset, u16 size = sizeof(Data))
-> Result<void>;
template <typename Data> void write_block_raw(
requires(sizeof(Data) <= block_size) u16 block_id, const void* data, size_t size, size_t offset = 0);
auto read_block(u16 block_id) -> Result<Data>; void read_block_raw(
template <typename Data> void* data, size_t size, u16 block_id, size_t offset = 0);
requires(sizeof(Data) <= block_size)
auto write_block(const Data& data, u16 block_id) -> Result<void>;
BlockDevice* m_disk; BlockDevice* m_disk;
Superblock m_superblock = {}; Superblock m_superblock = {};
BlocksBitmap m_blocks_bitmap = {}; BlocksBitmap m_blocks_bitmap = {};
bool m_out_of_sync = false;
}; };
} }

19
src/vm_main.cpp
View File

@ -18,8 +18,8 @@ using namespace vc5;
int main(int argc, char** argv) int main(int argc, char** argv)
{ {
auto device = IoDevice::create().value(); // auto device = IoDevice::create().value();
device->set_title("vc5"); // device->set_title("vc5");
if (argc > 2) { if (argc > 2) {
std::println("error: no boot disk (filename) specified"); std::println("error: no boot disk (filename) specified");
@ -37,19 +37,22 @@ int main(int argc, char** argv)
} }
try { try {
auto fs = filesys::Fs::init_new(disk, 0, 128).value(); auto fs = filesys::Fs(disk);
fs.init(0, 128);
auto root = fs.root_inode_id().value(); auto root = fs.root_inode();
auto file = fs.make_file(root, "test"); auto file = fs.make_file(root, "test");
} catch (std::bad_expected_access<std::string_view>& ex) { } catch (filesys::FsError& ex) {
std::println(stderr, "error: {}", ex.error()); std::println(stderr, "error: {}", ex.what());
return EXIT_FAILURE; return EXIT_FAILURE;
} }
auto vm = VM(*device, disk); // auto vm = VM(*device, disk);
vm.run(); // vm.run();
std::println("OK!");
} }
extern "C" const char* __asan_default_options(void) extern "C" const char* __asan_default_options(void)