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Kernel: Split ext2 implementation to multiple files

This commit is contained in:
Bananymous 2023-09-01 15:10:23 +03:00
parent d810644018
commit 7933265095
9 changed files with 791 additions and 762 deletions
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3
kernel/CMakeLists.txt
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@ -19,7 +19,8 @@ set(KERNEL_SOURCES
kernel/Errors.cpp kernel/Errors.cpp
kernel/Font.cpp kernel/Font.cpp
kernel/FS/DevFS/FileSystem.cpp kernel/FS/DevFS/FileSystem.cpp
kernel/FS/Ext2.cpp kernel/FS/Ext2/FileSystem.cpp
kernel/FS/Ext2/Inode.cpp
kernel/FS/Inode.cpp kernel/FS/Inode.cpp
kernel/FS/Pipe.cpp kernel/FS/Pipe.cpp
kernel/FS/RamFS/FileSystem.cpp kernel/FS/RamFS/FileSystem.cpp

225
kernel/include/kernel/FS/Ext2.h
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@ -1,225 +0,0 @@
#pragma once
#include <BAN/String.h>
#include <BAN/StringView.h>
#include <kernel/Storage/StorageDevice.h>
#include <kernel/FS/FileSystem.h>
namespace Kernel
{
namespace Ext2
{
struct Superblock
{
uint32_t inodes_count;
uint32_t blocks_count;
uint32_t r_blocks_count;
uint32_t free_blocks_count;
uint32_t free_inodes_count;
uint32_t first_data_block;
uint32_t log_block_size;
uint32_t log_frag_size;
uint32_t blocks_per_group;
uint32_t frags_per_group;
uint32_t inodes_per_group;
uint32_t mtime;
uint32_t wtime;
uint16_t mnt_count;
uint16_t max_mnt_count;
uint16_t magic;
uint16_t state;
uint16_t errors;
uint16_t minor_rev_level;
uint32_t lastcheck;
uint32_t checkinterval;
uint32_t creator_os;
uint32_t rev_level;
uint16_t def_resuid;
uint16_t def_resgid;
// -- EXT2_DYNAMIC_REV Specific --
uint8_t __extension_start[0];
uint32_t first_ino;
uint16_t inode_size;
uint16_t block_group_nr;
uint32_t feature_compat;
uint32_t feature_incompat;
uint32_t feature_ro_compat;
uint8_t uuid[16];
uint8_t volume_name[16];
char last_mounted[64];
uint32_t algo_bitmap;
// -- Performance Hints --
uint8_t s_prealloc_blocks;
uint8_t s_prealloc_dir_blocks;
uint16_t __alignment;
// -- Journaling Support --
uint8_t journal_uuid[16];
uint32_t journal_inum;
uint32_t journal_dev;
uint32_t last_orphan;
// -- Directory Indexing Support --
uint32_t hash_seed[4];
uint8_t def_hash_version;
uint8_t __padding[3];
// -- Other options --
uint32_t default_mount_options;
uint32_t first_meta_bg;
};
struct BlockGroupDescriptor
{
uint32_t block_bitmap;
uint32_t inode_bitmap;
uint32_t inode_table;
uint16_t free_blocks_count;
uint16_t free_inodes_count;
uint16_t used_dirs_count;
uint8_t __padding[2];
uint8_t __reserved[12];
};
struct Inode
{
uint16_t mode;
uint16_t uid;
uint32_t size;
uint32_t atime;
uint32_t ctime;
uint32_t mtime;
uint32_t dtime;
uint16_t gid;
uint16_t links_count;
uint32_t blocks;
uint32_t flags;
uint32_t osd1;
uint32_t block[15];
uint32_t generation;
uint32_t file_acl;
uint32_t dir_acl;
uint32_t faddr;
uint32_t osd2[3];
};
struct LinkedDirectoryEntry
{
uint32_t inode;
uint16_t rec_len;
uint8_t name_len;
uint8_t file_type;
char name[0];
};
}
class Ext2FS;
class Ext2Inode final : public Inode
{
public:
virtual ino_t ino() const override { return m_ino; };
virtual Mode mode() const override { return { m_inode.mode }; }
virtual nlink_t nlink() const override { return m_inode.links_count; }
virtual uid_t uid() const override { return m_inode.uid; }
virtual gid_t gid() const override { return m_inode.gid; }
virtual off_t size() const override { return m_inode.size; }
virtual timespec atime() const override { return timespec { .tv_sec = m_inode.atime, .tv_nsec = 0 }; }
virtual timespec mtime() const override { return timespec { .tv_sec = m_inode.mtime, .tv_nsec = 0 }; }
virtual timespec ctime() const override { return timespec { .tv_sec = m_inode.ctime, .tv_nsec = 0 }; }
virtual blksize_t blksize() const override;
virtual blkcnt_t blocks() const override;
virtual dev_t dev() const override { return 0; }
virtual dev_t rdev() const override { return 0; }
virtual BAN::ErrorOr<BAN::String> link_target() override;
virtual BAN::ErrorOr<void> directory_read_next_entries(off_t, DirectoryEntryList*, size_t) override;
virtual BAN::ErrorOr<BAN::RefPtr<Inode>> directory_find_inode(BAN::StringView) override;
virtual BAN::ErrorOr<size_t> read(size_t, void*, size_t) override;
virtual BAN::ErrorOr<size_t> write(size_t, const void*, size_t) override;
virtual BAN::ErrorOr<void> truncate(size_t) override;
virtual BAN::ErrorOr<void> create_file(BAN::StringView, mode_t, uid_t, gid_t) override;
private:
BAN::ErrorOr<void> for_data_block_index(uint32_t, const BAN::Function<void(uint32_t&)>&, bool allocate);
BAN::ErrorOr<uint32_t> data_block_index(uint32_t);
BAN::ErrorOr<uint32_t> allocate_new_block();
BAN::ErrorOr<void> sync();
uint32_t block_group() const;
private:
Ext2Inode(Ext2FS& fs, Ext2::Inode inode, uint32_t ino)
: m_fs(fs)
, m_inode(inode)
, m_ino(ino)
{}
static BAN::ErrorOr<BAN::RefPtr<Inode>> create(Ext2FS&, uint32_t);
private:
Ext2FS& m_fs;
Ext2::Inode m_inode;
const uint32_t m_ino;
friend class Ext2FS;
friend class BAN::RefPtr<Ext2Inode>;
};
class Ext2FS final : public FileSystem
{
public:
static BAN::ErrorOr<Ext2FS*> create(Partition&);
virtual BAN::RefPtr<Inode> root_inode() override { return m_root_inode; }
private:
Ext2FS(Partition& partition)
: m_partition(partition)
{}
BAN::ErrorOr<void> initialize_superblock();
BAN::ErrorOr<void> initialize_root_inode();
BAN::ErrorOr<uint32_t> create_inode(const Ext2::Inode&);
BAN::ErrorOr<void> delete_inode(uint32_t);
BAN::ErrorOr<void> resize_inode(uint32_t, size_t);
void read_block(uint32_t, BAN::Span<uint8_t>);
void write_block(uint32_t, BAN::Span<const uint8_t>);
void sync_superblock();
BAN::ErrorOr<uint32_t> reserve_free_block(uint32_t primary_bgd);
const Ext2::Superblock& superblock() const { return m_superblock; }
struct BlockLocation
{
uint32_t block;
uint32_t offset;
};
BAN::ErrorOr<BlockLocation> locate_inode(uint32_t);
BlockLocation locate_block_group_descriptior(uint32_t);
uint32_t block_size() const { return 1024 << superblock().log_block_size; }
private:
Partition& m_partition;
BAN::RefPtr<Inode> m_root_inode;
BAN::Vector<uint32_t> m_superblock_backups;
Ext2::Superblock m_superblock;
friend class Ext2Inode;
};
}

262
kernel/include/kernel/FS/Ext2/Definitions.h Normal file
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@ -0,0 +1,262 @@
#pragma once
#include <stdint.h>
namespace Kernel::Ext2
{
struct Superblock
{
uint32_t inodes_count;
uint32_t blocks_count;
uint32_t r_blocks_count;
uint32_t free_blocks_count;
uint32_t free_inodes_count;
uint32_t first_data_block;
uint32_t log_block_size;
uint32_t log_frag_size;
uint32_t blocks_per_group;
uint32_t frags_per_group;
uint32_t inodes_per_group;
uint32_t mtime;
uint32_t wtime;
uint16_t mnt_count;
uint16_t max_mnt_count;
uint16_t magic;
uint16_t state;
uint16_t errors;
uint16_t minor_rev_level;
uint32_t lastcheck;
uint32_t checkinterval;
uint32_t creator_os;
uint32_t rev_level;
uint16_t def_resuid;
uint16_t def_resgid;
// -- EXT2_DYNAMIC_REV Specific --
uint8_t __extension_start[0];
uint32_t first_ino;
uint16_t inode_size;
uint16_t block_group_nr;
uint32_t feature_compat;
uint32_t feature_incompat;
uint32_t feature_ro_compat;
uint8_t uuid[16];
uint8_t volume_name[16];
char last_mounted[64];
uint32_t algo_bitmap;
// -- Performance Hints --
uint8_t s_prealloc_blocks;
uint8_t s_prealloc_dir_blocks;
uint16_t __alignment;
// -- Journaling Support --
uint8_t journal_uuid[16];
uint32_t journal_inum;
uint32_t journal_dev;
uint32_t last_orphan;
// -- Directory Indexing Support --
uint32_t hash_seed[4];
uint8_t def_hash_version;
uint8_t __padding[3];
// -- Other options --
uint32_t default_mount_options;
uint32_t first_meta_bg;
};
struct BlockGroupDescriptor
{
uint32_t block_bitmap;
uint32_t inode_bitmap;
uint32_t inode_table;
uint16_t free_blocks_count;
uint16_t free_inodes_count;
uint16_t used_dirs_count;
uint8_t __padding[2];
uint8_t __reserved[12];
};
struct Inode
{
uint16_t mode;
uint16_t uid;
uint32_t size;
uint32_t atime;
uint32_t ctime;
uint32_t mtime;
uint32_t dtime;
uint16_t gid;
uint16_t links_count;
uint32_t blocks;
uint32_t flags;
uint32_t osd1;
uint32_t block[15];
uint32_t generation;
uint32_t file_acl;
uint32_t dir_acl;
uint32_t faddr;
uint32_t osd2[3];
};
struct LinkedDirectoryEntry
{
uint32_t inode;
uint16_t rec_len;
uint8_t name_len;
uint8_t file_type;
char name[0];
};
namespace Enum
{
constexpr uint16_t SUPER_MAGIC = 0xEF53;
enum State
{
VALID_FS = 1,
ERROR_FS = 2,
};
enum Errors
{
ERRORS_CONTINUE = 1,
ERRORS_RO = 2,
ERRORS_PANIC = 3,
};
enum CreatorOS
{
OS_LINUX = 0,
OS_HURD = 1,
OS_MASIX = 2,
OS_FREEBSD = 3,
OS_LITES = 4,
};
enum RevLevel
{
GOOD_OLD_REV = 0,
DYNAMIC_REV = 1,
};
enum Rev0Constant
{
GOOD_OLD_FIRST_INO = 11,
GOOD_OLD_INODE_SIZE = 128,
};
enum FeatureCompat
{
FEATURE_COMPAT_DIR_PREALLOC = 0x0001,
FEATURE_COMPAT_IMAGIC_INODES = 0x0002,
FEATURE_COMPAT_HAS_JOURNAL = 0x0004,
FEATURE_COMPAT_EXT_ATTR = 0x0008,
FEATURE_COMPAT_RESIZE_INO = 0x0010,
FEATURE_COMPAT_DIR_INDEX = 0x0020,
};
enum FeaturesIncompat
{
FEATURE_INCOMPAT_COMPRESSION = 0x0001,
FEATURE_INCOMPAT_FILETYPE = 0x0002,
FEATURE_INCOMPAT_RECOVER = 0x0004,
FEATURE_INCOMPAT_JOURNAL_DEV = 0x0008,
FEATURE_INCOMPAT_META_BG = 0x0010,
};
enum FeaturesRoCompat
{
FEATURE_RO_COMPAT_SPARSE_SUPER = 0x0001,
FEATURE_RO_COMPAT_LARGE_FILE = 0x0002,
FEATURE_RO_COMPAT_BTREE_DIR = 0x0004,
};
enum AlgoBitmap
{
LZV1_ALG = 0,
LZRW3A_ALG = 1,
GZIP_ALG = 2,
BZIP2_ALG = 3,
LZO_ALG = 4,
};
enum ReservedInodes
{
BAD_INO = 1,
ROOT_INO = 2,
ACL_IDX_INO = 3,
ACL_DATA_INO = 4,
BOOT_LOADER_INO = 5,
UNDEL_DIR_INO = 6,
};
enum InodeMode
{
// -- file format --
IFSOCK = 0xC000,
IFLNK = 0xA000,
IFREG = 0x8000,
IFBLK = 0x6000,
IFDIR = 0x4000,
IFCHR = 0x2000,
IFIFO = 0x1000,
// -- process execution user/group override --
ISUID = 0x0800,
ISGID = 0x0400,
ISVTX = 0x0200,
// -- access rights --
IRUSR = 0x0100,
IWUSR = 0x0080,
IXUSR = 0x0040,
IRGRP = 0x0020,
IWGRP = 0x0010,
IXGRP = 0x0008,
IROTH = 0x0004,
IWOTH = 0x0002,
IXOTH = 0x0001,
};
enum InodeFlags
{
SECRM_FL = 0x00000001,
UNRM_FL = 0x00000002,
COMPR_FL = 0x00000004,
SYNC_FL = 0x00000008,
IMMUTABLE_FL = 0x00000010,
APPEND_FL = 0x00000020,
NODUMP_FL = 0x00000040,
NOATIME_FL = 0x00000080,
// -- Reserved for compression usage --
DIRTY_FL = 0x00000100,
COMPRBLK_FL = 0x00000200,
NOCOMPR_FL = 0x00000400,
ECOMPR_FL = 0x00000800,
// -- End of compression flags --
BTREE_FL = 0x00001000,
INDEX_FL = 0x00001000,
IMAGIC_FL = 0x00002000,
JOURNAL_DATA_FL = 0x00004000,
RESERVED_FL = 0x80000000,
};
enum FileType
{
UNKNOWN = 0,
REG_FILE = 1,
DIR = 2,
CHRDEV = 3,
BLKDEV = 4,
FIFO = 5,
SOCK = 6,
SYMLINK = 7,
};
}
}

58
kernel/include/kernel/FS/Ext2/FileSystem.h Normal file
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@ -0,0 +1,58 @@
#pragma once
#include <kernel/Storage/StorageDevice.h>
#include <kernel/FS/FileSystem.h>
#include <kernel/FS/Ext2/Inode.h>
namespace Kernel
{
class Ext2FS final : public FileSystem
{
public:
static BAN::ErrorOr<Ext2FS*> create(Partition&);
virtual BAN::RefPtr<Inode> root_inode() override { return m_root_inode; }
private:
Ext2FS(Partition& partition)
: m_partition(partition)
{}
BAN::ErrorOr<void> initialize_superblock();
BAN::ErrorOr<void> initialize_root_inode();
BAN::ErrorOr<uint32_t> create_inode(const Ext2::Inode&);
BAN::ErrorOr<void> delete_inode(uint32_t);
BAN::ErrorOr<void> resize_inode(uint32_t, size_t);
void read_block(uint32_t, BAN::Span<uint8_t>);
void write_block(uint32_t, BAN::Span<const uint8_t>);
void sync_superblock();
BAN::ErrorOr<uint32_t> reserve_free_block(uint32_t primary_bgd);
const Ext2::Superblock& superblock() const { return m_superblock; }
struct BlockLocation
{
uint32_t block;
uint32_t offset;
};
BAN::ErrorOr<BlockLocation> locate_inode(uint32_t);
BlockLocation locate_block_group_descriptior(uint32_t);
uint32_t block_size() const { return 1024 << superblock().log_block_size; }
private:
Partition& m_partition;
BAN::RefPtr<Inode> m_root_inode;
BAN::Vector<uint32_t> m_superblock_backups;
Ext2::Superblock m_superblock;
friend class Ext2Inode;
};
}

67
kernel/include/kernel/FS/Ext2/Inode.h Normal file
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@ -0,0 +1,67 @@
#pragma once
#include <BAN/String.h>
#include <BAN/StringView.h>
#include <kernel/FS/Ext2/Definitions.h>
#include <kernel/FS/Inode.h>
namespace Kernel
{
class Ext2FS;
class Ext2Inode final : public Inode
{
public:
virtual ino_t ino() const override { return m_ino; };
virtual Mode mode() const override { return { m_inode.mode }; }
virtual nlink_t nlink() const override { return m_inode.links_count; }
virtual uid_t uid() const override { return m_inode.uid; }
virtual gid_t gid() const override { return m_inode.gid; }
virtual off_t size() const override { return m_inode.size; }
virtual timespec atime() const override { return timespec { .tv_sec = m_inode.atime, .tv_nsec = 0 }; }
virtual timespec mtime() const override { return timespec { .tv_sec = m_inode.mtime, .tv_nsec = 0 }; }
virtual timespec ctime() const override { return timespec { .tv_sec = m_inode.ctime, .tv_nsec = 0 }; }
virtual blksize_t blksize() const override;
virtual blkcnt_t blocks() const override;
virtual dev_t dev() const override { return 0; }
virtual dev_t rdev() const override { return 0; }
virtual BAN::ErrorOr<BAN::String> link_target() override;
virtual BAN::ErrorOr<void> directory_read_next_entries(off_t, DirectoryEntryList*, size_t) override;
virtual BAN::ErrorOr<BAN::RefPtr<Inode>> directory_find_inode(BAN::StringView) override;
virtual BAN::ErrorOr<size_t> read(size_t, void*, size_t) override;
virtual BAN::ErrorOr<size_t> write(size_t, const void*, size_t) override;
virtual BAN::ErrorOr<void> truncate(size_t) override;
virtual BAN::ErrorOr<void> create_file(BAN::StringView, mode_t, uid_t, gid_t) override;
private:
BAN::ErrorOr<void> for_data_block_index(uint32_t, const BAN::Function<void(uint32_t&)>&, bool allocate);
BAN::ErrorOr<uint32_t> data_block_index(uint32_t);
BAN::ErrorOr<uint32_t> allocate_new_block();
BAN::ErrorOr<void> sync();
uint32_t block_group() const;
private:
Ext2Inode(Ext2FS& fs, Ext2::Inode inode, uint32_t ino)
: m_fs(fs)
, m_inode(inode)
, m_ino(ino)
{}
static BAN::ErrorOr<BAN::RefPtr<Inode>> create(Ext2FS&, uint32_t);
private:
Ext2FS& m_fs;
Ext2::Inode m_inode;
const uint32_t m_ino;
friend class Ext2FS;
friend class BAN::RefPtr<Ext2Inode>;
};
}

396
kernel/kernel/FS/Ext2/FileSystem.cpp Normal file
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@ -0,0 +1,396 @@
#include <BAN/ScopeGuard.h>
#include <kernel/FS/Ext2/FileSystem.h>
#define EXT2_DEBUG_PRINT 1
namespace Kernel
{
BAN::ErrorOr<Ext2FS*> Ext2FS::create(Partition& partition)
{
Ext2FS* ext2fs = new Ext2FS(partition);
if (ext2fs == nullptr)
return BAN::Error::from_errno(ENOMEM);
BAN::ScopeGuard guard([ext2fs] { delete ext2fs; });
TRY(ext2fs->initialize_superblock());
TRY(ext2fs->initialize_root_inode());
guard.disable();
return ext2fs;
}
BAN::ErrorOr<void> Ext2FS::initialize_superblock()
{
// Read superblock from disk
{
const uint32_t sector_size = m_partition.device().sector_size();
ASSERT(1024 % sector_size == 0);
const uint32_t lba = 1024 / sector_size;
const uint32_t sector_count = BAN::Math::div_round_up<uint32_t>(sizeof(Ext2::Superblock), sector_size);
BAN::Vector<uint8_t> superblock_buffer;
TRY(superblock_buffer.resize(sector_count * sector_size));
TRY(m_partition.read_sectors(lba, sector_count, superblock_buffer.data()));
memcpy(&m_superblock, superblock_buffer.data(), sizeof(Ext2::Superblock));
}
if (m_superblock.magic != Ext2::Enum::SUPER_MAGIC)
return BAN::Error::from_error_code(ErrorCode::Ext2_Invalid);
if (m_superblock.rev_level == Ext2::Enum::GOOD_OLD_REV)
{
memset(m_superblock.__extension_start, 0, sizeof(Ext2::Superblock) - offsetof(Ext2::Superblock, Ext2::Superblock::__extension_start));
m_superblock.first_ino = Ext2::Enum::GOOD_OLD_FIRST_INO;
m_superblock.inode_size = Ext2::Enum::GOOD_OLD_INODE_SIZE;
}
const uint32_t number_of_block_groups = BAN::Math::div_round_up(superblock().inodes_count, superblock().inodes_per_group);
const uint32_t number_of_block_groups_check = BAN::Math::div_round_up(superblock().blocks_count, superblock().blocks_per_group);
if (number_of_block_groups != number_of_block_groups_check)
return BAN::Error::from_error_code(ErrorCode::Ext2_Corrupted);
if (!(m_superblock.feature_incompat & Ext2::Enum::FEATURE_INCOMPAT_FILETYPE))
{
dwarnln("Directory entries without filetype not supported");
return BAN::Error::from_errno(ENOTSUP);
}
if (m_superblock.feature_incompat & Ext2::Enum::FEATURE_INCOMPAT_COMPRESSION)
{
dwarnln("Required FEATURE_INCOMPAT_COMPRESSION");
return BAN::Error::from_errno(ENOTSUP);
}
if (m_superblock.feature_incompat & Ext2::Enum::FEATURE_INCOMPAT_JOURNAL_DEV)
{
dwarnln("Required FEATURE_INCOMPAT_JOURNAL_DEV");
return BAN::Error::from_errno(ENOTSUP);
}
if (m_superblock.feature_incompat & Ext2::Enum::FEATURE_INCOMPAT_META_BG)
{
dwarnln("Required FEATURE_INCOMPAT_META_BG");
return BAN::Error::from_errno(ENOTSUP);
}
if (m_superblock.feature_incompat & Ext2::Enum::FEATURE_INCOMPAT_RECOVER)
{
dwarnln("Required FEATURE_INCOMPAT_RECOVER");
return BAN::Error::from_errno(ENOTSUP);
}
#if EXT2_DEBUG_PRINT
dprintln("EXT2");
dprintln(" inodes {}", m_superblock.inodes_count);
dprintln(" blocks {}", m_superblock.blocks_count);
dprintln(" version {}.{}", m_superblock.rev_level, m_superblock.minor_rev_level);
dprintln(" first data at {}", m_superblock.first_data_block);
dprintln(" block size {}", 1024 << m_superblock.log_block_size);
dprintln(" inode size {}", m_superblock.inode_size);
dprintln(" inodes/group {}", m_superblock.inodes_per_group);
#endif
{
BAN::Vector<uint8_t> block_buffer;
TRY(block_buffer.resize(block_size()));
if (superblock().rev_level == Ext2::Enum::GOOD_OLD_REV)
{
// In revision 0 all blockgroups contain superblock backup
TRY(m_superblock_backups.reserve(number_of_block_groups - 1));
for (uint32_t i = 1; i < number_of_block_groups; i++)
MUST(block_buffer.push_back(i));
}
else
{
// In other revision superblock backups are on blocks 1 and powers of 3, 5 and 7
TRY(m_superblock_backups.push_back(1));
for (uint32_t i = 3; i < number_of_block_groups; i *= 3)
TRY(m_superblock_backups.push_back(i));
for (uint32_t i = 5; i < number_of_block_groups; i *= 5)
TRY(m_superblock_backups.push_back(i));
for (uint32_t i = 7; i < number_of_block_groups; i *= 7)
TRY(m_superblock_backups.push_back(i));
// We don't really care if this succeeds or not
(void)m_superblock_backups.shrink_to_fit();
}
for (uint32_t bg : m_superblock_backups)
{
read_block(superblock().first_data_block + superblock().blocks_per_group * bg, block_buffer.span());
Ext2::Superblock& superblock_backup = *(Ext2::Superblock*)block_buffer.data();
if (superblock_backup.magic != Ext2::Enum::SUPER_MAGIC)
derrorln("superblock backup at block {} is invalid ({4H})", bg, superblock_backup.magic);
}
}
return {};
}
BAN::ErrorOr<void> Ext2FS::initialize_root_inode()
{
m_root_inode = TRY(Ext2Inode::create(*this, Ext2::Enum::ROOT_INO));
#if EXT2_DEBUG_PRINT
dprintln("root inode:");
dprintln(" created {}", root_inode()->ctime().tv_sec);
dprintln(" modified {}", root_inode()->mtime().tv_sec);
dprintln(" accessed {}", root_inode()->atime().tv_sec);
#endif
return {};
}
BAN::ErrorOr<uint32_t> Ext2FS::create_inode(const Ext2::Inode& ext2_inode)
{
ASSERT(ext2_inode.size == 0);
if (m_superblock.free_inodes_count == 0)
return BAN::Error::from_errno(ENOSPC);
const uint32_t block_size = this->block_size();
BAN::Vector<uint8_t> bgd_buffer;
TRY(bgd_buffer.resize(block_size));
BAN::Vector<uint8_t> inode_bitmap;
TRY(inode_bitmap.resize(block_size));
uint32_t current_group = -1;
BlockLocation bgd_location {};
Ext2::BlockGroupDescriptor* bgd = nullptr;
for (uint32_t ino = superblock().inodes_per_group + 1; ino <= superblock().inodes_count; ino++)
{
const uint32_t ino_group = (ino - 1) / superblock().inodes_per_group;
const uint32_t ino_index = (ino - 1) % superblock().inodes_per_group;
if (ino_group != current_group)
{
current_group = ino_group;
bgd_location = locate_block_group_descriptior(current_group);
read_block(bgd_location.block, bgd_buffer.span());
bgd = (Ext2::BlockGroupDescriptor*)(bgd_buffer.data() + bgd_location.offset);
if (bgd->free_inodes_count == 0)
{
ino = superblock().first_ino + (current_group + 1) * superblock().inodes_per_group - 1;
continue;
}
read_block(bgd->inode_bitmap, inode_bitmap.span());
}
const uint32_t ino_bitmap_byte = ino_index / 8;
const uint32_t ino_bitmap_bit = ino_index % 8;
if (inode_bitmap[ino_bitmap_byte] & (1 << ino_bitmap_bit))
continue;
inode_bitmap[ino_bitmap_byte] |= 1 << ino_bitmap_bit;
write_block(bgd->inode_bitmap, inode_bitmap.span());
bgd->free_inodes_count--;
write_block(bgd_location.block, bgd_buffer.span());
const uint32_t inode_table_offset = ino_index * superblock().inode_size;
const BlockLocation inode_location
{
.block = inode_table_offset / block_size + bgd->inode_table,
.offset = inode_table_offset % block_size
};
dprintln("allocated inode {} at offset {2H}",
ino,
2048 + (inode_location.block - 2) * block_size + inode_location.offset
);
dprintln("bitmap byte at {2H} with bit {2H}",
2048 + (bgd->inode_bitmap - 2) * block_size + ino_bitmap_byte,
1 << ino_bitmap_bit
);
// NOTE: we don't need inode bitmap anymore, so we can reuse it
auto& inode_buffer = inode_bitmap;
read_block(inode_location.block, inode_buffer.span());
memcpy(inode_buffer.data() + inode_location.offset, &ext2_inode, sizeof(Ext2::Inode));
if (superblock().inode_size > sizeof(Ext2::Inode))
memset(inode_buffer.data() + inode_location.offset + sizeof(Ext2::Inode), 0, superblock().inode_size - sizeof(Ext2::Inode));
write_block(inode_location.block, inode_buffer.span());
m_superblock.free_inodes_count--;
sync_superblock();
return ino;
}
derrorln("Corrupted file system. Superblock indicates free inodes but none were found.");
return BAN::Error::from_error_code(ErrorCode::Ext2_Corrupted);
}
void Ext2FS::read_block(uint32_t block, BAN::Span<uint8_t> buffer)
{
const uint32_t sector_size = m_partition.device().sector_size();
const uint32_t block_size = this->block_size();
const uint32_t sectors_per_block = block_size / sector_size;
const uint32_t sectors_before = 2048 / sector_size;
ASSERT(block >= 2);
ASSERT(buffer.size() >= block_size);
MUST(m_partition.read_sectors(sectors_before + (block - 2) * sectors_per_block, sectors_per_block, buffer.data()));
}
void Ext2FS::write_block(uint32_t block, BAN::Span<const uint8_t> buffer)
{
const uint32_t sector_size = m_partition.device().sector_size();
const uint32_t block_size = this->block_size();
const uint32_t sectors_per_block = block_size / sector_size;
const uint32_t sectors_before = 2048 / sector_size;
ASSERT(block >= 2);
ASSERT(buffer.size() >= block_size);
MUST(m_partition.write_sectors(sectors_before + (block - 2) * sectors_per_block, sectors_per_block, buffer.data()));
}
void Ext2FS::sync_superblock()
{
const uint32_t sector_size = m_partition.device().sector_size();
ASSERT(1024 % sector_size == 0);
const uint32_t superblock_bytes =
(m_superblock.rev_level == Ext2::Enum::GOOD_OLD_REV)
? offsetof(Ext2::Superblock, __extension_start)
: sizeof(Ext2::Superblock);
const uint32_t lba = 1024 / sector_size;
const uint32_t sector_count = BAN::Math::div_round_up<uint32_t>(superblock_bytes, sector_size);
BAN::Vector<uint8_t> superblock_buffer;
MUST(superblock_buffer.resize(sector_count * sector_size));
MUST(m_partition.read_sectors(lba, sector_count, superblock_buffer.data()));
if (memcmp(superblock_buffer.data(), &m_superblock, superblock_bytes))
{
memcpy(superblock_buffer.data(), &m_superblock, superblock_bytes);
MUST(m_partition.write_sectors(lba, sector_count, superblock_buffer.data()));
}
}
BAN::ErrorOr<uint32_t> Ext2FS::reserve_free_block(uint32_t primary_bgd)
{
if (m_superblock.r_blocks_count >= m_superblock.free_blocks_count)
return BAN::Error::from_errno(ENOSPC);
const uint32_t block_size = this->block_size();
BAN::Vector<uint8_t> bgd_buffer;
TRY(bgd_buffer.resize(block_size));
BAN::Vector<uint8_t> block_bitmap;
TRY(block_bitmap.resize(block_size));
auto check_block_group =
[&](uint32_t block_group) -> uint32_t
{
auto bgd_location = locate_block_group_descriptior(block_group);
read_block(bgd_location.block, bgd_buffer.span());
auto& bgd = *(Ext2::BlockGroupDescriptor*)(bgd_buffer.data() + bgd_location.offset);
if (bgd.free_blocks_count == 0)
return 0;
read_block(bgd.block_bitmap, block_bitmap.span());
for (uint32_t block_offset = 0; block_offset < m_superblock.blocks_per_group; block_offset++)
{
uint32_t byte = block_offset / 8;
uint32_t bit = block_offset % 8;
if (block_bitmap[byte] & (1 << bit))
continue;
block_bitmap[byte] |= 1 << bit;
write_block(bgd.block_bitmap, block_bitmap.span());
bgd.free_blocks_count--;
write_block(bgd_location.block, bgd_buffer.span());
m_superblock.free_blocks_count--;
sync_superblock();
return m_superblock.first_data_block + m_superblock.blocks_per_group * block_group + block_offset;
}
derrorln("Corrupted file system. Block group descriptor indicates free blocks but none were found");
return 0;
};
if (auto ret = check_block_group(primary_bgd))
return ret;
uint32_t number_of_block_groups = BAN::Math::div_round_up(m_superblock.blocks_count, m_superblock.blocks_per_group);
for (uint32_t block_group = 0; block_group < number_of_block_groups; block_group++)
if (block_group != primary_bgd)
if (auto ret = check_block_group(block_group))
return ret;
derrorln("Corrupted file system. Superblock indicates free blocks but none were found.");
return BAN::Error::from_error_code(ErrorCode::Ext2_Corrupted);
}
BAN::ErrorOr<Ext2FS::BlockLocation> Ext2FS::locate_inode(uint32_t ino)
{
ASSERT(ino < superblock().inodes_count);
const uint32_t block_size = this->block_size();
BAN::Vector<uint8_t> bgd_buffer;
TRY(bgd_buffer.resize(block_size));
const uint32_t inode_group = (ino - 1) / superblock().inodes_per_group;
const uint32_t inode_index = (ino - 1) % superblock().inodes_per_group;
auto bgd_location = locate_block_group_descriptior(inode_group);
read_block(bgd_location.block, bgd_buffer.span());
auto& bgd = *(Ext2::BlockGroupDescriptor*)(bgd_buffer.data() + bgd_location.offset);
const uint32_t inode_byte_offset = inode_index * superblock().inode_size;
BlockLocation location
{
.block = inode_byte_offset / block_size + bgd.inode_table,
.offset = inode_byte_offset % block_size
};
#if VERIFY_INODE_EXISTANCE
const uint32_t inode_bitmap_block = bgd.inode_bitmap;
// NOTE: we can reuse the bgd_buffer since it is not needed anymore
auto& inode_bitmap = bgd_buffer;
read_block(inode_bitmap_block, inode_bitmap.span());
const uint32_t byte = inode_index / 8;
const uint32_t bit = inode_index % 8;
ASSERT(inode_bitmap[byte] & (1 << bit));
#endif
return location;
}
Ext2FS::BlockLocation Ext2FS::locate_block_group_descriptior(uint32_t group_index)
{
const uint32_t block_size = this->block_size();
const uint32_t block_group_count = BAN::Math::div_round_up(superblock().inodes_count, superblock().inodes_per_group);
ASSERT(group_index < block_group_count);
// Block Group Descriptor table is always after the superblock
// Superblock begins at byte 1024 and is exactly 1024 bytes wide
const uint32_t bgd_byte_offset = 2048 + sizeof(Ext2::BlockGroupDescriptor) * group_index;
return
{
.block = bgd_byte_offset / block_size,
.offset = bgd_byte_offset % block_size
};
}
}

539
kernel/kernel/FS/Ext2.cpp → kernel/kernel/FS/Ext2/Inode.cpp
View File

@ -1,163 +1,13 @@
#include <BAN/ScopeGuard.h> #include <BAN/Function.h>
#include <BAN/StringView.h> #include <kernel/FS/Ext2/FileSystem.h>
#include <kernel/FS/Ext2.h> #include <kernel/FS/Ext2/Inode.h>
#include <kernel/Timer/Timer.h> #include <kernel/Timer/Timer.h>
#define EXT2_DEBUG_PRINT 0 #define EXT2_DEBUG_PRINT 1
#define VERIFY_INODE_EXISTANCE 1
namespace Kernel namespace Kernel
{ {
namespace Ext2::Enum
{
constexpr uint16_t SUPER_MAGIC = 0xEF53;
enum State
{
VALID_FS = 1,
ERROR_FS = 2,
};
enum Errors
{
ERRORS_CONTINUE = 1,
ERRORS_RO = 2,
ERRORS_PANIC = 3,
};
enum CreatorOS
{
OS_LINUX = 0,
OS_HURD = 1,
OS_MASIX = 2,
OS_FREEBSD = 3,
OS_LITES = 4,
};
enum RevLevel
{
GOOD_OLD_REV = 0,
DYNAMIC_REV = 1,
};
enum Rev0Constant
{
GOOD_OLD_FIRST_INO = 11,
GOOD_OLD_INODE_SIZE = 128,
};
enum FeatureCompat
{
FEATURE_COMPAT_DIR_PREALLOC = 0x0001,
FEATURE_COMPAT_IMAGIC_INODES = 0x0002,
FEATURE_COMPAT_HAS_JOURNAL = 0x0004,
FEATURE_COMPAT_EXT_ATTR = 0x0008,
FEATURE_COMPAT_RESIZE_INO = 0x0010,
FEATURE_COMPAT_DIR_INDEX = 0x0020,
};
enum FeaturesIncompat
{
FEATURE_INCOMPAT_COMPRESSION = 0x0001,
FEATURE_INCOMPAT_FILETYPE = 0x0002,
FEATURE_INCOMPAT_RECOVER = 0x0004,
FEATURE_INCOMPAT_JOURNAL_DEV = 0x0008,
FEATURE_INCOMPAT_META_BG = 0x0010,
};
enum FeaturesRoCompat
{
FEATURE_RO_COMPAT_SPARSE_SUPER = 0x0001,
FEATURE_RO_COMPAT_LARGE_FILE = 0x0002,
FEATURE_RO_COMPAT_BTREE_DIR = 0x0004,
};
enum AlgoBitmap
{
LZV1_ALG = 0,
LZRW3A_ALG = 1,
GZIP_ALG = 2,
BZIP2_ALG = 3,
LZO_ALG = 4,
};
enum ReservedInodes
{
BAD_INO = 1,
ROOT_INO = 2,
ACL_IDX_INO = 3,
ACL_DATA_INO = 4,
BOOT_LOADER_INO = 5,
UNDEL_DIR_INO = 6,
};
enum InodeMode
{
// -- file format --
IFSOCK = 0xC000,
IFLNK = 0xA000,
IFREG = 0x8000,
IFBLK = 0x6000,
IFDIR = 0x4000,
IFCHR = 0x2000,
IFIFO = 0x1000,
// -- process execution user/group override --
ISUID = 0x0800,
ISGID = 0x0400,
ISVTX = 0x0200,
// -- access rights --
IRUSR = 0x0100,
IWUSR = 0x0080,
IXUSR = 0x0040,
IRGRP = 0x0020,
IWGRP = 0x0010,
IXGRP = 0x0008,
IROTH = 0x0004,
IWOTH = 0x0002,
IXOTH = 0x0001,
};
enum InodeFlags
{
SECRM_FL = 0x00000001,
UNRM_FL = 0x00000002,
COMPR_FL = 0x00000004,
SYNC_FL = 0x00000008,
IMMUTABLE_FL = 0x00000010,
APPEND_FL = 0x00000020,
NODUMP_FL = 0x00000040,
NOATIME_FL = 0x00000080,
// -- Reserved for compression usage --
DIRTY_FL = 0x00000100,
COMPRBLK_FL = 0x00000200,
NOCOMPR_FL = 0x00000400,
ECOMPR_FL = 0x00000800,
// -- End of compression flags --
BTREE_FL = 0x00001000,
INDEX_FL = 0x00001000,
IMAGIC_FL = 0x00002000,
JOURNAL_DATA_FL = 0x00004000,
RESERVED_FL = 0x80000000,
};
enum FileType
{
UNKNOWN = 0,
REG_FILE = 1,
DIR = 2,
CHRDEV = 3,
BLKDEV = 4,
FIFO = 5,
SOCK = 6,
SYMLINK = 7,
};
}
blksize_t Ext2Inode::blksize() const blksize_t Ext2Inode::blksize() const
{ {
return m_fs.block_size(); return m_fs.block_size();
@ -556,7 +406,7 @@ namespace Kernel
.mtime = (uint32_t)current_time.tv_sec, .mtime = (uint32_t)current_time.tv_sec,
.dtime = 0, .dtime = 0,
.gid = (uint16_t)gid, .gid = (uint16_t)gid,
.links_count = 1, .links_count = 5,
.blocks = 0, .blocks = 0,
.flags = 0, .flags = 0,
.osd1 = 0, .osd1 = 0,
@ -725,383 +575,4 @@ needs_new_block:
return BAN::Error::from_errno(ENOENT); return BAN::Error::from_errno(ENOENT);
} }
BAN::ErrorOr<Ext2FS*> Ext2FS::create(Partition& partition)
{
Ext2FS* ext2fs = new Ext2FS(partition);
if (ext2fs == nullptr)
return BAN::Error::from_errno(ENOMEM);
BAN::ScopeGuard guard([ext2fs] { delete ext2fs; });
TRY(ext2fs->initialize_superblock());
TRY(ext2fs->initialize_root_inode());
guard.disable();
return ext2fs;
}
BAN::ErrorOr<void> Ext2FS::initialize_superblock()
{
// Read superblock from disk
{
const uint32_t sector_size = m_partition.device().sector_size();
ASSERT(1024 % sector_size == 0);
const uint32_t lba = 1024 / sector_size;
const uint32_t sector_count = BAN::Math::div_round_up<uint32_t>(sizeof(Ext2::Superblock), sector_size);
BAN::Vector<uint8_t> superblock_buffer;
TRY(superblock_buffer.resize(sector_count * sector_size));
TRY(m_partition.read_sectors(lba, sector_count, superblock_buffer.data()));
memcpy(&m_superblock, superblock_buffer.data(), sizeof(Ext2::Superblock));
}
if (m_superblock.magic != Ext2::Enum::SUPER_MAGIC)
return BAN::Error::from_error_code(ErrorCode::Ext2_Invalid);
if (m_superblock.rev_level == Ext2::Enum::GOOD_OLD_REV)
{
memset(m_superblock.__extension_start, 0, sizeof(Ext2::Superblock) - offsetof(Ext2::Superblock, Ext2::Superblock::__extension_start));
m_superblock.first_ino = Ext2::Enum::GOOD_OLD_FIRST_INO;
m_superblock.inode_size = Ext2::Enum::GOOD_OLD_INODE_SIZE;
}
const uint32_t number_of_block_groups = BAN::Math::div_round_up(superblock().inodes_count, superblock().inodes_per_group);
const uint32_t number_of_block_groups_check = BAN::Math::div_round_up(superblock().blocks_count, superblock().blocks_per_group);
if (number_of_block_groups != number_of_block_groups_check)
return BAN::Error::from_error_code(ErrorCode::Ext2_Corrupted);
if (!(m_superblock.feature_incompat & Ext2::Enum::FEATURE_INCOMPAT_FILETYPE))
{
dwarnln("Directory entries without filetype not supported");
return BAN::Error::from_errno(ENOTSUP);
}
if (m_superblock.feature_incompat & Ext2::Enum::FEATURE_INCOMPAT_COMPRESSION)
{
dwarnln("Required FEATURE_INCOMPAT_COMPRESSION");
return BAN::Error::from_errno(ENOTSUP);
}
if (m_superblock.feature_incompat & Ext2::Enum::FEATURE_INCOMPAT_JOURNAL_DEV)
{
dwarnln("Required FEATURE_INCOMPAT_JOURNAL_DEV");
return BAN::Error::from_errno(ENOTSUP);
}
if (m_superblock.feature_incompat & Ext2::Enum::FEATURE_INCOMPAT_META_BG)
{
dwarnln("Required FEATURE_INCOMPAT_META_BG");
return BAN::Error::from_errno(ENOTSUP);
}
if (m_superblock.feature_incompat & Ext2::Enum::FEATURE_INCOMPAT_RECOVER)
{
dwarnln("Required FEATURE_INCOMPAT_RECOVER");
return BAN::Error::from_errno(ENOTSUP);
}
#if EXT2_DEBUG_PRINT
dprintln("EXT2");
dprintln(" inodes {}", m_superblock.inodes_count);
dprintln(" blocks {}", m_superblock.blocks_count);
dprintln(" version {}.{}", m_superblock.rev_level, m_superblock.minor_rev_level);
dprintln(" first data at {}", m_superblock.first_data_block);
dprintln(" block size {}", 1024 << m_superblock.log_block_size);
dprintln(" inode size {}", m_superblock.inode_size);
#endif
{
BAN::Vector<uint8_t> block_buffer;
TRY(block_buffer.resize(block_size()));
if (superblock().rev_level == Ext2::Enum::GOOD_OLD_REV)
{
// In revision 0 all blockgroups contain superblock backup
TRY(m_superblock_backups.reserve(number_of_block_groups - 1));
for (uint32_t i = 1; i < number_of_block_groups; i++)
MUST(block_buffer.push_back(i));
}
else
{
// In other revision superblock backups are on blocks 1 and powers of 3, 5 and 7
TRY(m_superblock_backups.push_back(1));
for (uint32_t i = 3; i < number_of_block_groups; i *= 3)
TRY(m_superblock_backups.push_back(i));
for (uint32_t i = 5; i < number_of_block_groups; i *= 5)
TRY(m_superblock_backups.push_back(i));
for (uint32_t i = 7; i < number_of_block_groups; i *= 7)
TRY(m_superblock_backups.push_back(i));
// We don't really care if this succeeds or not
(void)m_superblock_backups.shrink_to_fit();
}
for (uint32_t bg : m_superblock_backups)
{
read_block(superblock().first_data_block + superblock().blocks_per_group * bg, block_buffer.span());
Ext2::Superblock& superblock_backup = *(Ext2::Superblock*)block_buffer.data();
if (superblock_backup.magic != Ext2::Enum::SUPER_MAGIC)
derrorln("superblock backup at block {} is invalid ({4H})", bg, superblock_backup.magic);
}
}
return {};
}
BAN::ErrorOr<void> Ext2FS::initialize_root_inode()
{
m_root_inode = TRY(Ext2Inode::create(*this, Ext2::Enum::ROOT_INO));
//(void)locate_inode(2271);
#if EXT2_DEBUG_PRINT
dprintln("root inode:");
dprintln(" created {}", root_inode()->ctime().tv_sec);
dprintln(" modified {}", root_inode()->mtime().tv_sec);
dprintln(" accessed {}", root_inode()->atime().tv_sec);
#endif
return {};
}
BAN::ErrorOr<uint32_t> Ext2FS::create_inode(const Ext2::Inode& ext2_inode)
{
ASSERT(ext2_inode.size == 0);
if (m_superblock.free_inodes_count == 0)
return BAN::Error::from_errno(ENOSPC);
const uint32_t block_size = this->block_size();
BAN::Vector<uint8_t> bgd_buffer;
TRY(bgd_buffer.resize(block_size));
BAN::Vector<uint8_t> inode_bitmap;
TRY(inode_bitmap.resize(block_size));
uint32_t current_group = -1;
BlockLocation bgd_location {};
Ext2::BlockGroupDescriptor* bgd = nullptr;
for (uint32_t ino = superblock().first_ino; ino <= superblock().inodes_count; ino++)
{
const uint32_t ino_group = (ino - 1) / superblock().inodes_per_group;
const uint32_t ino_index = (ino - 1) % superblock().inodes_per_group;
if (ino_group != current_group)
{
current_group = ino_group;
bgd_location = locate_block_group_descriptior(current_group);
read_block(bgd_location.block, bgd_buffer.span());
bgd = (Ext2::BlockGroupDescriptor*)(bgd_buffer.data() + bgd_location.offset);
if (bgd->free_inodes_count == 0)
{
ino = (current_group + 1) * superblock().inodes_per_group;
continue;
}
read_block(bgd->inode_bitmap, inode_bitmap.span());
}
const uint32_t ino_bitmap_byte = ino_index / 8;
const uint32_t ino_bitmap_bit = ino_index % 8;
if (inode_bitmap[ino_bitmap_byte] & (1 << ino_bitmap_bit))
continue;
inode_bitmap[ino_bitmap_byte] |= 1 << ino_bitmap_bit;
write_block(bgd->inode_bitmap, inode_bitmap.span());
bgd->free_inodes_count--;
write_block(bgd_location.block, bgd_buffer.span());
const uint32_t inode_table_offset = ino_index * superblock().inode_size;
const BlockLocation inode_location
{
.block = inode_table_offset / block_size + bgd->inode_table,
.offset = inode_table_offset % block_size
};
// NOTE: we don't need inode bitmap anymore, so we can reuse it
auto& inode_buffer = inode_bitmap;
read_block(inode_location.block, inode_buffer.span());
memcpy(inode_buffer.data() + inode_location.offset, &ext2_inode, sizeof(Ext2::Inode));
if (superblock().inode_size > sizeof(Ext2::Inode))
memset(inode_buffer.data() + inode_location.offset + sizeof(Ext2::Inode), 0, superblock().inode_size - sizeof(Ext2::Inode));
write_block(inode_location.block, inode_buffer.span());
m_superblock.free_inodes_count--;
sync_superblock();
return ino;
}
derrorln("Corrupted file system. Superblock indicates free inodes but none were found.");
return BAN::Error::from_error_code(ErrorCode::Ext2_Corrupted);
}
void Ext2FS::read_block(uint32_t block, BAN::Span<uint8_t> buffer)
{
const uint32_t sector_size = m_partition.device().sector_size();
const uint32_t block_size = this->block_size();
const uint32_t sectors_per_block = block_size / sector_size;
const uint32_t sectors_before = 2048 / sector_size;
ASSERT(block >= 2);
ASSERT(buffer.size() >= block_size);
MUST(m_partition.read_sectors(sectors_before + (block - 2) * sectors_per_block, sectors_per_block, buffer.data()));
}
void Ext2FS::write_block(uint32_t block, BAN::Span<const uint8_t> buffer)
{
const uint32_t sector_size = m_partition.device().sector_size();
const uint32_t block_size = this->block_size();
const uint32_t sectors_per_block = block_size / sector_size;
const uint32_t sectors_before = 2048 / sector_size;
ASSERT(block >= 2);
ASSERT(buffer.size() >= block_size);
MUST(m_partition.write_sectors(sectors_before + (block - 2) * sectors_per_block, sectors_per_block, buffer.data()));
}
void Ext2FS::sync_superblock()
{
const uint32_t sector_size = m_partition.device().sector_size();
ASSERT(1024 % sector_size == 0);
const uint32_t superblock_bytes =
(m_superblock.rev_level == Ext2::Enum::GOOD_OLD_REV)
? offsetof(Ext2::Superblock, __extension_start)
: sizeof(Ext2::Superblock);
const uint32_t lba = 1024 / sector_size;
const uint32_t sector_count = BAN::Math::div_round_up<uint32_t>(superblock_bytes, sector_size);
BAN::Vector<uint8_t> superblock_buffer;
MUST(superblock_buffer.resize(sector_count * sector_size));
MUST(m_partition.read_sectors(lba, sector_count, superblock_buffer.data()));
if (memcmp(superblock_buffer.data(), &m_superblock, superblock_bytes))
{
memcpy(superblock_buffer.data(), &m_superblock, superblock_bytes);
MUST(m_partition.write_sectors(lba, sector_count, superblock_buffer.data()));
}
}
BAN::ErrorOr<uint32_t> Ext2FS::reserve_free_block(uint32_t primary_bgd)
{
if (m_superblock.r_blocks_count >= m_superblock.free_blocks_count)
return BAN::Error::from_errno(ENOSPC);
const uint32_t block_size = this->block_size();
BAN::Vector<uint8_t> bgd_buffer;
TRY(bgd_buffer.resize(block_size));
BAN::Vector<uint8_t> block_bitmap;
TRY(block_bitmap.resize(block_size));
auto check_block_group =
[&](uint32_t block_group) -> uint32_t
{
auto bgd_location = locate_block_group_descriptior(block_group);
read_block(bgd_location.block, bgd_buffer.span());
auto& bgd = *(Ext2::BlockGroupDescriptor*)(bgd_buffer.data() + bgd_location.offset);
if (bgd.free_blocks_count == 0)
return 0;
read_block(bgd.block_bitmap, block_bitmap.span());
for (uint32_t block_offset = 0; block_offset < m_superblock.blocks_per_group; block_offset++)
{
uint32_t byte = block_offset / 8;
uint32_t bit = block_offset % 8;
if (block_bitmap[byte] & (1 << bit))
continue;
block_bitmap[byte] |= 1 << bit;
write_block(bgd.block_bitmap, block_bitmap.span());
bgd.free_blocks_count--;
write_block(bgd_location.block, bgd_buffer.span());
m_superblock.free_blocks_count--;
sync_superblock();
return m_superblock.first_data_block + m_superblock.blocks_per_group * block_group + block_offset;
}
derrorln("Corrupted file system. Block group descriptor indicates free blocks but none were found");
return 0;
};
if (auto ret = check_block_group(primary_bgd))
return ret;
uint32_t number_of_block_groups = BAN::Math::div_round_up(m_superblock.blocks_count, m_superblock.blocks_per_group);
for (uint32_t block_group = 0; block_group < number_of_block_groups; block_group++)
if (block_group != primary_bgd)
if (auto ret = check_block_group(block_group))
return ret;
derrorln("Corrupted file system. Superblock indicates free blocks but none were found.");
return BAN::Error::from_error_code(ErrorCode::Ext2_Corrupted);
}
BAN::ErrorOr<Ext2FS::BlockLocation> Ext2FS::locate_inode(uint32_t ino)
{
ASSERT(ino < superblock().inodes_count);
const uint32_t block_size = this->block_size();
BAN::Vector<uint8_t> bgd_buffer;
TRY(bgd_buffer.resize(block_size));
const uint32_t inode_group = (ino - 1) / superblock().inodes_per_group;
const uint32_t inode_index = (ino - 1) % superblock().inodes_per_group;
auto bgd_location = locate_block_group_descriptior(inode_group);
read_block(bgd_location.block, bgd_buffer.span());
auto& bgd = *(Ext2::BlockGroupDescriptor*)(bgd_buffer.data() + bgd_location.offset);
const uint32_t inode_byte_offset = inode_index * superblock().inode_size;
BlockLocation location
{
.block = inode_byte_offset / block_size + bgd.inode_table,
.offset = inode_byte_offset % block_size
};
#if VERIFY_INODE_EXISTANCE
const uint32_t inode_bitmap_block = bgd.inode_bitmap;
// NOTE: we can reuse the bgd_buffer since it is not needed anymore
auto& inode_bitmap = bgd_buffer;
read_block(inode_bitmap_block, inode_bitmap.span());
const uint32_t byte = inode_index / 8;
const uint32_t bit = inode_index % 8;
ASSERT(inode_bitmap[byte] & (1 << bit));
#endif
return location;
}
Ext2FS::BlockLocation Ext2FS::locate_block_group_descriptior(uint32_t group_index)
{
const uint32_t block_size = this->block_size();
const uint32_t block_group_count = BAN::Math::div_round_up(superblock().inodes_count, superblock().inodes_per_group);
ASSERT(group_index < block_group_count);
// Block Group Descriptor table is always after the superblock
// Superblock begins at byte 1024 and is exactly 1024 bytes wide
const uint32_t bgd_byte_offset = 2048 + sizeof(Ext2::BlockGroupDescriptor) * group_index;
return
{
.block = bgd_byte_offset / block_size,
.offset = bgd_byte_offset % block_size
};
}
} }

2
kernel/kernel/FS/VirtualFileSystem.cpp
View File

@ -1,7 +1,7 @@
#include <BAN/ScopeGuard.h> #include <BAN/ScopeGuard.h>
#include <BAN/StringView.h> #include <BAN/StringView.h>
#include <kernel/FS/DevFS/FileSystem.h> #include <kernel/FS/DevFS/FileSystem.h>
#include <kernel/FS/Ext2.h> #include <kernel/FS/Ext2/FileSystem.h>
#include <kernel/FS/RamFS/FileSystem.h> #include <kernel/FS/RamFS/FileSystem.h>
#include <kernel/FS/RamFS/Inode.h> #include <kernel/FS/RamFS/Inode.h>
#include <kernel/FS/VirtualFileSystem.h> #include <kernel/FS/VirtualFileSystem.h>

1
kernel/kernel/Storage/StorageDevice.cpp
View File

@ -2,7 +2,6 @@
#include <BAN/ScopeGuard.h> #include <BAN/ScopeGuard.h>
#include <BAN/StringView.h> #include <BAN/StringView.h>
#include <BAN/UTF8.h> #include <BAN/UTF8.h>
#include <kernel/FS/Ext2.h>
#include <kernel/FS/VirtualFileSystem.h> #include <kernel/FS/VirtualFileSystem.h>
#include <kernel/PCI.h> #include <kernel/PCI.h>
#include <kernel/Storage/StorageDevice.h> #include <kernel/Storage/StorageDevice.h>