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ladybird/Kernel/FileSystem/Ext2FileSystem.cpp
Andreas Kling 280694bb46 Kernel: Update atime/ctime/mtime timestamps atomically 
Instead of having three separate APIs (one for each timestamp),
there's now only Inode::update_timestamps() and it takes 3x optional
timestamps. The non-empty timestamps are updated while holding the inode
mutex, and the outside world no longer has to look at intermediate
timestamp states.
2022-08-22 17:56:03 +02:00

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/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* Copyright (c) 2021, sin-ack <sin-ack@protonmail.com>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/HashMap.h>
#include <AK/MemoryStream.h>
#include <AK/StdLibExtras.h>
#include <AK/StringView.h>
#include <Kernel/API/POSIX/errno.h>
#include <Kernel/Debug.h>
#include <Kernel/Devices/BlockDevice.h>
#include <Kernel/FileSystem/Ext2FileSystem.h>
#include <Kernel/FileSystem/OpenFileDescription.h>
#include <Kernel/FileSystem/ext2_fs.h>
#include <Kernel/Process.h>
#include <Kernel/UnixTypes.h>
namespace Kernel {
static constexpr size_t max_block_size = 4096;
static constexpr size_t max_inline_symlink_length = 60;
struct Ext2FSDirectoryEntry {
NonnullOwnPtr<KString> name;
InodeIndex inode_index { 0 };
u8 file_type { 0 };
u16 record_length { 0 };
};
static u8 to_ext2_file_type(mode_t mode)
{
if (is_regular_file(mode))
return EXT2_FT_REG_FILE;
if (is_directory(mode))
return EXT2_FT_DIR;
if (is_character_device(mode))
return EXT2_FT_CHRDEV;
if (is_block_device(mode))
return EXT2_FT_BLKDEV;
if (is_fifo(mode))
return EXT2_FT_FIFO;
if (is_socket(mode))
return EXT2_FT_SOCK;
if (is_symlink(mode))
return EXT2_FT_SYMLINK;
return EXT2_FT_UNKNOWN;
}
ErrorOr<NonnullLockRefPtr<FileSystem>> Ext2FS::try_create(OpenFileDescription& file_description)
{
return TRY(adopt_nonnull_lock_ref_or_enomem(new (nothrow) Ext2FS(file_description)));
}
Ext2FS::Ext2FS(OpenFileDescription& file_description)
: BlockBasedFileSystem(file_description)
{
}
Ext2FS::~Ext2FS() = default;
ErrorOr<void> Ext2FS::flush_super_block()
{
MutexLocker locker(m_lock);
VERIFY((sizeof(ext2_super_block) % logical_block_size()) == 0);
auto super_block_buffer = UserOrKernelBuffer::for_kernel_buffer((u8*)&m_super_block);
return raw_write_blocks(2, (sizeof(ext2_super_block) / logical_block_size()), super_block_buffer);
}
ext2_group_desc const& Ext2FS::group_descriptor(GroupIndex group_index) const
{
// FIXME: Should this fail gracefully somehow?
VERIFY(group_index <= m_block_group_count);
VERIFY(group_index > 0);
return block_group_descriptors()[group_index.value() - 1];
}
ErrorOr<void> Ext2FS::initialize()
{
MutexLocker locker(m_lock);
VERIFY((sizeof(ext2_super_block) % logical_block_size()) == 0);
auto super_block_buffer = UserOrKernelBuffer::for_kernel_buffer((u8*)&m_super_block);
TRY(raw_read_blocks(2, (sizeof(ext2_super_block) / logical_block_size()), super_block_buffer));
auto const& super_block = this->super_block();
if constexpr (EXT2_DEBUG) {
dmesgln("Ext2FS: super block magic: {:04x} (super block size: {})", super_block.s_magic, sizeof(ext2_super_block));
}
if (super_block.s_magic != EXT2_SUPER_MAGIC) {
dmesgln("Ext2FS: Bad super block magic");
return EINVAL;
}
if constexpr (EXT2_DEBUG) {
dmesgln("Ext2FS: {} inodes, {} blocks", super_block.s_inodes_count, super_block.s_blocks_count);
dmesgln("Ext2FS: Block size: {}", EXT2_BLOCK_SIZE(&super_block));
dmesgln("Ext2FS: First data block: {}", super_block.s_first_data_block);
dmesgln("Ext2FS: Inodes per block: {}", inodes_per_block());
dmesgln("Ext2FS: Inodes per group: {}", inodes_per_group());
dmesgln("Ext2FS: Free inodes: {}", super_block.s_free_inodes_count);
dmesgln("Ext2FS: Descriptors per block: {}", EXT2_DESC_PER_BLOCK(&super_block));
dmesgln("Ext2FS: Descriptor size: {}", EXT2_DESC_SIZE(&super_block));
}
set_block_size(EXT2_BLOCK_SIZE(&super_block));
set_fragment_size(EXT2_FRAG_SIZE(&super_block));
// Note: This depends on the block size being available.
TRY(BlockBasedFileSystem::initialize());
VERIFY(block_size() <= (int)max_block_size);
m_block_group_count = ceil_div(super_block.s_blocks_count, super_block.s_blocks_per_group);
if (m_block_group_count == 0) {
dmesgln("Ext2FS: no block groups :(");
return EINVAL;
}
auto blocks_to_read = ceil_div(m_block_group_count * sizeof(ext2_group_desc), block_size());
BlockIndex first_block_of_bgdt = block_size() == 1024 ? 2 : 1;
m_cached_group_descriptor_table = TRY(KBuffer::try_create_with_size("Ext2FS: Block group descriptors"sv, block_size() * blocks_to_read, Memory::Region::Access::ReadWrite));
auto buffer = UserOrKernelBuffer::for_kernel_buffer(m_cached_group_descriptor_table->data());
TRY(read_blocks(first_block_of_bgdt, blocks_to_read, buffer));
if constexpr (EXT2_DEBUG) {
for (unsigned i = 1; i <= m_block_group_count; ++i) {
auto const& group = group_descriptor(i);
dbgln("Ext2FS: group[{}] ( block_bitmap: {}, inode_bitmap: {}, inode_table: {} )", i, group.bg_block_bitmap, group.bg_inode_bitmap, group.bg_inode_table);
}
}
m_root_inode = static_ptr_cast<Ext2FSInode>(TRY(get_inode({ fsid(), EXT2_ROOT_INO })));
return {};
}
Ext2FSInode& Ext2FS::root_inode()
{
return *m_root_inode;
}
bool Ext2FS::find_block_containing_inode(InodeIndex inode, BlockIndex& block_index, unsigned& offset) const
{
auto const& super_block = this->super_block();
if (inode != EXT2_ROOT_INO && inode < EXT2_FIRST_INO(&super_block))
return false;
if (inode > super_block.s_inodes_count)
return false;
auto const& bgd = group_descriptor(group_index_from_inode(inode));
u64 full_offset = ((inode.value() - 1) % inodes_per_group()) * inode_size();
block_index = bgd.bg_inode_table + (full_offset >> EXT2_BLOCK_SIZE_BITS(&super_block));
offset = full_offset & (block_size() - 1);
return true;
}
Ext2FS::BlockListShape Ext2FS::compute_block_list_shape(unsigned blocks) const
{
BlockListShape shape;
unsigned const entries_per_block = EXT2_ADDR_PER_BLOCK(&super_block());
unsigned blocks_remaining = blocks;
shape.direct_blocks = min((unsigned)EXT2_NDIR_BLOCKS, blocks_remaining);
blocks_remaining -= shape.direct_blocks;
if (!blocks_remaining)
return shape;
shape.indirect_blocks = min(blocks_remaining, entries_per_block);
shape.meta_blocks += 1;
blocks_remaining -= shape.indirect_blocks;
if (!blocks_remaining)
return shape;
shape.doubly_indirect_blocks = min(blocks_remaining, entries_per_block * entries_per_block);
shape.meta_blocks += 1;
shape.meta_blocks += ceil_div(shape.doubly_indirect_blocks, entries_per_block);
blocks_remaining -= shape.doubly_indirect_blocks;
if (!blocks_remaining)
return shape;
shape.triply_indirect_blocks = min(blocks_remaining, entries_per_block * entries_per_block * entries_per_block);
shape.meta_blocks += 1;
shape.meta_blocks += ceil_div(shape.triply_indirect_blocks, entries_per_block * entries_per_block);
shape.meta_blocks += ceil_div(shape.triply_indirect_blocks, entries_per_block);
blocks_remaining -= shape.triply_indirect_blocks;
VERIFY(blocks_remaining == 0);
return shape;
}
ErrorOr<void> Ext2FSInode::write_indirect_block(BlockBasedFileSystem::BlockIndex block, Span<BlockBasedFileSystem::BlockIndex> blocks_indices)
{
auto const entries_per_block = EXT2_ADDR_PER_BLOCK(&fs().super_block());
VERIFY(blocks_indices.size() <= entries_per_block);
auto block_contents = TRY(ByteBuffer::create_uninitialized(fs().block_size()));
OutputMemoryStream stream { block_contents };
auto buffer = UserOrKernelBuffer::for_kernel_buffer(stream.data());
VERIFY(blocks_indices.size() <= EXT2_ADDR_PER_BLOCK(&fs().super_block()));
for (unsigned i = 0; i < blocks_indices.size(); ++i)
stream << static_cast<u32>(blocks_indices[i].value());
stream.fill_to_end(0);
return fs().write_block(block, buffer, stream.size());
}
ErrorOr<void> Ext2FSInode::grow_doubly_indirect_block(BlockBasedFileSystem::BlockIndex block, size_t old_blocks_length, Span<BlockBasedFileSystem::BlockIndex> blocks_indices, Vector<Ext2FS::BlockIndex>& new_meta_blocks, unsigned& meta_blocks)
{
auto const entries_per_block = EXT2_ADDR_PER_BLOCK(&fs().super_block());
auto const entries_per_doubly_indirect_block = entries_per_block * entries_per_block;
auto const old_indirect_blocks_length = ceil_div(old_blocks_length, entries_per_block);
auto const new_indirect_blocks_length = ceil_div(blocks_indices.size(), entries_per_block);
VERIFY(blocks_indices.size() > 0);
VERIFY(blocks_indices.size() > old_blocks_length);
VERIFY(blocks_indices.size() <= entries_per_doubly_indirect_block);
auto block_contents = TRY(ByteBuffer::create_uninitialized(fs().block_size()));
auto* block_as_pointers = (unsigned*)block_contents.data();
OutputMemoryStream stream { block_contents };
auto buffer = UserOrKernelBuffer::for_kernel_buffer(stream.data());
if (old_blocks_length > 0) {
TRY(fs().read_block(block, &buffer, fs().block_size()));
}
// Grow the doubly indirect block.
for (unsigned i = 0; i < old_indirect_blocks_length; i++)
stream << static_cast<u32>(block_as_pointers[i]);
for (unsigned i = old_indirect_blocks_length; i < new_indirect_blocks_length; i++) {
auto new_block = new_meta_blocks.take_last().value();
dbgln_if(EXT2_BLOCKLIST_DEBUG, "Ext2FSInode[{}]::grow_doubly_indirect_block(): Allocating indirect block {} at index {}", identifier(), new_block, i);
stream << static_cast<u32>(new_block);
meta_blocks++;
}
stream.fill_to_end(0);
// Write out the indirect blocks.
for (unsigned i = old_blocks_length / entries_per_block; i < new_indirect_blocks_length; i++) {
auto const offset_block = i * entries_per_block;
TRY(write_indirect_block(block_as_pointers[i], blocks_indices.slice(offset_block, min(blocks_indices.size() - offset_block, entries_per_block))));
}
// Write out the doubly indirect block.
return fs().write_block(block, buffer, stream.size());
}
ErrorOr<void> Ext2FSInode::shrink_doubly_indirect_block(BlockBasedFileSystem::BlockIndex block, size_t old_blocks_length, size_t new_blocks_length, unsigned& meta_blocks)
{
auto const entries_per_block = EXT2_ADDR_PER_BLOCK(&fs().super_block());
auto const entries_per_doubly_indirect_block = entries_per_block * entries_per_block;
auto const old_indirect_blocks_length = ceil_div(old_blocks_length, entries_per_block);
auto const new_indirect_blocks_length = ceil_div(new_blocks_length, entries_per_block);
VERIFY(old_blocks_length > 0);
VERIFY(old_blocks_length >= new_blocks_length);
VERIFY(new_blocks_length <= entries_per_doubly_indirect_block);
auto block_contents = TRY(ByteBuffer::create_uninitialized(fs().block_size()));
auto* block_as_pointers = (unsigned*)block_contents.data();
auto buffer = UserOrKernelBuffer::for_kernel_buffer(reinterpret_cast<u8*>(block_as_pointers));
TRY(fs().read_block(block, &buffer, fs().block_size()));
// Free the unused indirect blocks.
for (unsigned i = new_indirect_blocks_length; i < old_indirect_blocks_length; i++) {
dbgln_if(EXT2_BLOCKLIST_DEBUG, "Ext2FSInode[{}]::shrink_doubly_indirect_block(): Freeing indirect block {} at index {}", identifier(), block_as_pointers[i], i);
TRY(fs().set_block_allocation_state(block_as_pointers[i], false));
meta_blocks--;
}
// Free the doubly indirect block if no longer needed.
if (new_blocks_length == 0) {
dbgln_if(EXT2_BLOCKLIST_DEBUG, "Ext2FSInode[{}]::shrink_doubly_indirect_block(): Freeing doubly indirect block {}", identifier(), block);
TRY(fs().set_block_allocation_state(block, false));
meta_blocks--;
}
return {};
}
ErrorOr<void> Ext2FSInode::grow_triply_indirect_block(BlockBasedFileSystem::BlockIndex block, size_t old_blocks_length, Span<BlockBasedFileSystem::BlockIndex> blocks_indices, Vector<Ext2FS::BlockIndex>& new_meta_blocks, unsigned& meta_blocks)
{
auto const entries_per_block = EXT2_ADDR_PER_BLOCK(&fs().super_block());
auto const entries_per_doubly_indirect_block = entries_per_block * entries_per_block;
auto const entries_per_triply_indirect_block = entries_per_block * entries_per_block;
auto const old_doubly_indirect_blocks_length = ceil_div(old_blocks_length, entries_per_doubly_indirect_block);
auto const new_doubly_indirect_blocks_length = ceil_div(blocks_indices.size(), entries_per_doubly_indirect_block);
VERIFY(blocks_indices.size() > 0);
VERIFY(blocks_indices.size() > old_blocks_length);
VERIFY(blocks_indices.size() <= entries_per_triply_indirect_block);
auto block_contents = TRY(ByteBuffer::create_uninitialized(fs().block_size()));
auto* block_as_pointers = (unsigned*)block_contents.data();
OutputMemoryStream stream { block_contents };
auto buffer = UserOrKernelBuffer::for_kernel_buffer(stream.data());
if (old_blocks_length > 0) {
TRY(fs().read_block(block, &buffer, fs().block_size()));
}
// Grow the triply indirect block.
for (unsigned i = 0; i < old_doubly_indirect_blocks_length; i++)
stream << static_cast<u32>(block_as_pointers[i]);
for (unsigned i = old_doubly_indirect_blocks_length; i < new_doubly_indirect_blocks_length; i++) {
auto new_block = new_meta_blocks.take_last().value();
dbgln_if(EXT2_BLOCKLIST_DEBUG, "Ext2FSInode[{}]::grow_triply_indirect_block(): Allocating doubly indirect block {} at index {}", identifier(), new_block, i);
stream << static_cast<u32>(new_block);
meta_blocks++;
}
stream.fill_to_end(0);
// Write out the doubly indirect blocks.
for (unsigned i = old_blocks_length / entries_per_doubly_indirect_block; i < new_doubly_indirect_blocks_length; i++) {
auto const processed_blocks = i * entries_per_doubly_indirect_block;
auto const old_doubly_indirect_blocks_length = min(old_blocks_length > processed_blocks ? old_blocks_length - processed_blocks : 0, entries_per_doubly_indirect_block);
auto const new_doubly_indirect_blocks_length = min(blocks_indices.size() > processed_blocks ? blocks_indices.size() - processed_blocks : 0, entries_per_doubly_indirect_block);
TRY(grow_doubly_indirect_block(block_as_pointers[i], old_doubly_indirect_blocks_length, blocks_indices.slice(processed_blocks, new_doubly_indirect_blocks_length), new_meta_blocks, meta_blocks));
}
// Write out the triply indirect block.
return fs().write_block(block, buffer, stream.size());
}
ErrorOr<void> Ext2FSInode::shrink_triply_indirect_block(BlockBasedFileSystem::BlockIndex block, size_t old_blocks_length, size_t new_blocks_length, unsigned& meta_blocks)
{
auto const entries_per_block = EXT2_ADDR_PER_BLOCK(&fs().super_block());
auto const entries_per_doubly_indirect_block = entries_per_block * entries_per_block;
auto const entries_per_triply_indirect_block = entries_per_doubly_indirect_block * entries_per_block;
auto const old_triply_indirect_blocks_length = ceil_div(old_blocks_length, entries_per_doubly_indirect_block);
auto const new_triply_indirect_blocks_length = new_blocks_length / entries_per_doubly_indirect_block;
VERIFY(old_blocks_length > 0);
VERIFY(old_blocks_length >= new_blocks_length);
VERIFY(new_blocks_length <= entries_per_triply_indirect_block);
auto block_contents = TRY(ByteBuffer::create_uninitialized(fs().block_size()));
auto* block_as_pointers = (unsigned*)block_contents.data();
auto buffer = UserOrKernelBuffer::for_kernel_buffer(reinterpret_cast<u8*>(block_as_pointers));
TRY(fs().read_block(block, &buffer, fs().block_size()));
// Shrink the doubly indirect blocks.
for (unsigned i = new_triply_indirect_blocks_length; i < old_triply_indirect_blocks_length; i++) {
auto const processed_blocks = i * entries_per_doubly_indirect_block;
auto const old_doubly_indirect_blocks_length = min(old_blocks_length > processed_blocks ? old_blocks_length - processed_blocks : 0, entries_per_doubly_indirect_block);
auto const new_doubly_indirect_blocks_length = min(new_blocks_length > processed_blocks ? new_blocks_length - processed_blocks : 0, entries_per_doubly_indirect_block);
dbgln_if(EXT2_BLOCKLIST_DEBUG, "Ext2FSInode[{}]::shrink_triply_indirect_block(): Shrinking doubly indirect block {} at index {}", identifier(), block_as_pointers[i], i);
TRY(shrink_doubly_indirect_block(block_as_pointers[i], old_doubly_indirect_blocks_length, new_doubly_indirect_blocks_length, meta_blocks));
}
// Free the triply indirect block if no longer needed.
if (new_blocks_length == 0) {
dbgln_if(EXT2_BLOCKLIST_DEBUG, "Ext2FSInode[{}]::shrink_triply_indirect_block(): Freeing triply indirect block {}", identifier(), block);
TRY(fs().set_block_allocation_state(block, false));
meta_blocks--;
}
return {};
}
ErrorOr<void> Ext2FSInode::flush_block_list()
{
MutexLocker locker(m_inode_lock);
if (m_block_list.is_empty()) {
m_raw_inode.i_blocks = 0;
memset(m_raw_inode.i_block, 0, sizeof(m_raw_inode.i_block));
set_metadata_dirty(true);
return {};
}
// NOTE: There is a mismatch between i_blocks and blocks.size() since i_blocks includes meta blocks and blocks.size() does not.
auto const old_block_count = ceil_div(size(), static_cast<u64>(fs().block_size()));
auto old_shape = fs().compute_block_list_shape(old_block_count);
auto const new_shape = fs().compute_block_list_shape(m_block_list.size());
Vector<Ext2FS::BlockIndex> new_meta_blocks;
if (new_shape.meta_blocks > old_shape.meta_blocks) {
new_meta_blocks = TRY(fs().allocate_blocks(fs().group_index_from_inode(index()), new_shape.meta_blocks - old_shape.meta_blocks));
}
m_raw_inode.i_blocks = (m_block_list.size() + new_shape.meta_blocks) * (fs().block_size() / 512);
dbgln_if(EXT2_BLOCKLIST_DEBUG, "Ext2FSInode[{}]::flush_block_list(): Old shape=({};{};{};{}:{}), new shape=({};{};{};{}:{})", identifier(), old_shape.direct_blocks, old_shape.indirect_blocks, old_shape.doubly_indirect_blocks, old_shape.triply_indirect_blocks, old_shape.meta_blocks, new_shape.direct_blocks, new_shape.indirect_blocks, new_shape.doubly_indirect_blocks, new_shape.triply_indirect_blocks, new_shape.meta_blocks);
unsigned output_block_index = 0;
unsigned remaining_blocks = m_block_list.size();
// Deal with direct blocks.
bool inode_dirty = false;
VERIFY(new_shape.direct_blocks <= EXT2_NDIR_BLOCKS);
for (unsigned i = 0; i < new_shape.direct_blocks; ++i) {
if (BlockBasedFileSystem::BlockIndex(m_raw_inode.i_block[i]) != m_block_list[output_block_index])
inode_dirty = true;
m_raw_inode.i_block[i] = m_block_list[output_block_index].value();
++output_block_index;
--remaining_blocks;
}
// e2fsck considers all blocks reachable through any of the pointers in
// m_raw_inode.i_block as part of this inode regardless of the value in
// m_raw_inode.i_size. When it finds more blocks than the amount that
// is indicated by i_size or i_blocks it offers to repair the filesystem
// by changing those values. That will actually cause further corruption.
// So we must zero all pointers to blocks that are now unused.
for (unsigned i = new_shape.direct_blocks; i < EXT2_NDIR_BLOCKS; ++i) {
m_raw_inode.i_block[i] = 0;
}
if (inode_dirty) {
if constexpr (EXT2_DEBUG) {
dbgln("Ext2FSInode[{}]::flush_block_list(): Writing {} direct block(s) to i_block array of inode {}", identifier(), min((size_t)EXT2_NDIR_BLOCKS, m_block_list.size()), index());
for (size_t i = 0; i < min((size_t)EXT2_NDIR_BLOCKS, m_block_list.size()); ++i)
dbgln(" + {}", m_block_list[i]);
}
set_metadata_dirty(true);
}
// Deal with indirect blocks.
if (old_shape.indirect_blocks != new_shape.indirect_blocks) {
if (new_shape.indirect_blocks > old_shape.indirect_blocks) {
// Write out the indirect block.
if (old_shape.indirect_blocks == 0) {
auto new_block = new_meta_blocks.take_last().value();
dbgln_if(EXT2_BLOCKLIST_DEBUG, "Ext2FSInode[{}]::flush_block_list(): Allocating indirect block: {}", identifier(), new_block);
m_raw_inode.i_block[EXT2_IND_BLOCK] = new_block;
set_metadata_dirty(true);
old_shape.meta_blocks++;
}
TRY(write_indirect_block(m_raw_inode.i_block[EXT2_IND_BLOCK], m_block_list.span().slice(output_block_index, new_shape.indirect_blocks)));
} else if ((new_shape.indirect_blocks == 0) && (old_shape.indirect_blocks != 0)) {
dbgln_if(EXT2_BLOCKLIST_DEBUG, "Ext2FSInode[{}]::flush_block_list(): Freeing indirect block: {}", identifier(), m_raw_inode.i_block[EXT2_IND_BLOCK]);
TRY(fs().set_block_allocation_state(m_raw_inode.i_block[EXT2_IND_BLOCK], false));
old_shape.meta_blocks--;
m_raw_inode.i_block[EXT2_IND_BLOCK] = 0;
}
}
remaining_blocks -= new_shape.indirect_blocks;
output_block_index += new_shape.indirect_blocks;
if (old_shape.doubly_indirect_blocks != new_shape.doubly_indirect_blocks) {
// Write out the doubly indirect block.
if (new_shape.doubly_indirect_blocks > old_shape.doubly_indirect_blocks) {
if (old_shape.doubly_indirect_blocks == 0) {
auto new_block = new_meta_blocks.take_last().value();
dbgln_if(EXT2_BLOCKLIST_DEBUG, "Ext2FSInode[{}]::flush_block_list(): Allocating doubly indirect block: {}", identifier(), new_block);
m_raw_inode.i_block[EXT2_DIND_BLOCK] = new_block;
set_metadata_dirty(true);
old_shape.meta_blocks++;
}
TRY(grow_doubly_indirect_block(m_raw_inode.i_block[EXT2_DIND_BLOCK], old_shape.doubly_indirect_blocks, m_block_list.span().slice(output_block_index, new_shape.doubly_indirect_blocks), new_meta_blocks, old_shape.meta_blocks));
} else {
TRY(shrink_doubly_indirect_block(m_raw_inode.i_block[EXT2_DIND_BLOCK], old_shape.doubly_indirect_blocks, new_shape.doubly_indirect_blocks, old_shape.meta_blocks));
if (new_shape.doubly_indirect_blocks == 0)
m_raw_inode.i_block[EXT2_DIND_BLOCK] = 0;
}
}
remaining_blocks -= new_shape.doubly_indirect_blocks;
output_block_index += new_shape.doubly_indirect_blocks;
if (old_shape.triply_indirect_blocks != new_shape.triply_indirect_blocks) {
// Write out the triply indirect block.
if (new_shape.triply_indirect_blocks > old_shape.triply_indirect_blocks) {
if (old_shape.triply_indirect_blocks == 0) {
auto new_block = new_meta_blocks.take_last().value();
dbgln_if(EXT2_BLOCKLIST_DEBUG, "Ext2FSInode[{}]::flush_block_list(): Allocating triply indirect block: {}", identifier(), new_block);
m_raw_inode.i_block[EXT2_TIND_BLOCK] = new_block;
set_metadata_dirty(true);
old_shape.meta_blocks++;
}
TRY(grow_triply_indirect_block(m_raw_inode.i_block[EXT2_TIND_BLOCK], old_shape.triply_indirect_blocks, m_block_list.span().slice(output_block_index, new_shape.triply_indirect_blocks), new_meta_blocks, old_shape.meta_blocks));
} else {
TRY(shrink_triply_indirect_block(m_raw_inode.i_block[EXT2_TIND_BLOCK], old_shape.triply_indirect_blocks, new_shape.triply_indirect_blocks, old_shape.meta_blocks));
if (new_shape.triply_indirect_blocks == 0)
m_raw_inode.i_block[EXT2_TIND_BLOCK] = 0;
}
}
remaining_blocks -= new_shape.triply_indirect_blocks;
output_block_index += new_shape.triply_indirect_blocks;
dbgln_if(EXT2_BLOCKLIST_DEBUG, "Ext2FSInode[{}]::flush_block_list(): New meta blocks count at {}, expecting {}", identifier(), old_shape.meta_blocks, new_shape.meta_blocks);
VERIFY(new_meta_blocks.size() == 0);
VERIFY(old_shape.meta_blocks == new_shape.meta_blocks);
if (!remaining_blocks)
return {};
dbgln("we don't know how to write qind ext2fs blocks, they don't exist anyway!");
VERIFY_NOT_REACHED();
}
ErrorOr<Vector<Ext2FS::BlockIndex>> Ext2FSInode::compute_block_list() const
{
return compute_block_list_impl(false);
}
ErrorOr<Vector<Ext2FS::BlockIndex>> Ext2FSInode::compute_block_list_with_meta_blocks() const
{
return compute_block_list_impl(true);
}
ErrorOr<Vector<Ext2FS::BlockIndex>> Ext2FSInode::compute_block_list_impl(bool include_block_list_blocks) const
{
// FIXME: This is really awkwardly factored.. foo_impl_internal :|
auto block_list = TRY(compute_block_list_impl_internal(m_raw_inode, include_block_list_blocks));
while (!block_list.is_empty() && block_list.last() == 0)
block_list.take_last();
return block_list;
}
ErrorOr<Vector<Ext2FS::BlockIndex>> Ext2FSInode::compute_block_list_impl_internal(ext2_inode const& e2inode, bool include_block_list_blocks) const
{
unsigned entries_per_block = EXT2_ADDR_PER_BLOCK(&fs().super_block());
unsigned block_count = ceil_div(size(), static_cast<u64>(fs().block_size()));
// If we are handling a symbolic link, the path is stored in the 60 bytes in
// the inode that are used for the 12 direct and 3 indirect block pointers,
// If the path is longer than 60 characters, a block is allocated, and the
// block contains the destination path. The file size corresponds to the
// path length of the destination.
if (::is_symlink(e2inode.i_mode) && e2inode.i_blocks == 0)
block_count = 0;
dbgln_if(EXT2_DEBUG, "Ext2FSInode[{}]::block_list_for_inode(): i_size={}, i_blocks={}, block_count={}", identifier(), e2inode.i_size, e2inode.i_blocks, block_count);
unsigned blocks_remaining = block_count;
if (include_block_list_blocks) {
auto shape = fs().compute_block_list_shape(block_count);
blocks_remaining += shape.meta_blocks;
}
Vector<Ext2FS::BlockIndex> list;
auto add_block = [&](auto bi) -> ErrorOr<void> {
if (blocks_remaining) {
TRY(list.try_append(bi));
--blocks_remaining;
}
return {};
};
if (include_block_list_blocks) {
// This seems like an excessive over-estimate but w/e.
TRY(list.try_ensure_capacity(blocks_remaining * 2));
} else {
TRY(list.try_ensure_capacity(blocks_remaining));
}
unsigned direct_count = min(block_count, (unsigned)EXT2_NDIR_BLOCKS);
for (unsigned i = 0; i < direct_count; ++i) {
auto block_index = e2inode.i_block[i];
TRY(add_block(block_index));
}
if (!blocks_remaining)
return list;
// Don't need to make copy of add_block, since this capture will only
// be called before compute_block_list_impl_internal finishes.
auto process_block_array = [&](auto array_block_index, auto&& callback) -> ErrorOr<void> {
if (include_block_list_blocks)
TRY(add_block(array_block_index));
auto count = min(blocks_remaining, entries_per_block);
if (!count)
return {};
size_t read_size = count * sizeof(u32);
auto array_storage = TRY(ByteBuffer::create_uninitialized(read_size));
auto* array = (u32*)array_storage.data();
auto buffer = UserOrKernelBuffer::for_kernel_buffer((u8*)array);
TRY(fs().read_block(array_block_index, &buffer, read_size, 0));
for (unsigned i = 0; i < count; ++i)
TRY(callback(Ext2FS::BlockIndex(array[i])));
return {};
};
TRY(process_block_array(e2inode.i_block[EXT2_IND_BLOCK], [&](auto block_index) -> ErrorOr<void> {
return add_block(block_index);
}));
if (!blocks_remaining)
return list;
TRY(process_block_array(e2inode.i_block[EXT2_DIND_BLOCK], [&](auto block_index) -> ErrorOr<void> {
return process_block_array(block_index, [&](auto block_index2) -> ErrorOr<void> {
return add_block(block_index2);
});
}));
if (!blocks_remaining)
return list;
TRY(process_block_array(e2inode.i_block[EXT2_TIND_BLOCK], [&](auto block_index) -> ErrorOr<void> {
return process_block_array(block_index, [&](auto block_index2) -> ErrorOr<void> {
return process_block_array(block_index2, [&](auto block_index3) -> ErrorOr<void> {
return add_block(block_index3);
});
});
}));
return list;
}
ErrorOr<void> Ext2FS::free_inode(Ext2FSInode& inode)
{
MutexLocker locker(m_lock);
VERIFY(inode.m_raw_inode.i_links_count == 0);
dbgln_if(EXT2_DEBUG, "Ext2FS[{}]::free_inode(): Inode {} has no more links, time to delete!", fsid(), inode.index());
// Mark all blocks used by this inode as free.
{
auto blocks = TRY(inode.compute_block_list_with_meta_blocks());
for (auto block_index : blocks) {
VERIFY(block_index <= super_block().s_blocks_count);
if (block_index.value())
TRY(set_block_allocation_state(block_index, false));
}
}
// If the inode being freed is a directory, update block group directory counter.
if (inode.is_directory()) {
auto& bgd = const_cast<ext2_group_desc&>(group_descriptor(group_index_from_inode(inode.index())));
--bgd.bg_used_dirs_count;
dbgln_if(EXT2_DEBUG, "Ext2FS[{}]::free_inode(): Decremented bg_used_dirs_count to {} for inode {}", fsid(), bgd.bg_used_dirs_count, inode.index());
m_block_group_descriptors_dirty = true;
}
// NOTE: After this point, the inode metadata is wiped.
memset(&inode.m_raw_inode, 0, sizeof(ext2_inode));
inode.m_raw_inode.i_dtime = kgettimeofday().to_truncated_seconds();
TRY(write_ext2_inode(inode.index(), inode.m_raw_inode));
// Mark the inode as free.
TRY(set_inode_allocation_state(inode.index(), false));
return {};
}
void Ext2FS::flush_block_group_descriptor_table()
{
MutexLocker locker(m_lock);
auto blocks_to_write = ceil_div(m_block_group_count * sizeof(ext2_group_desc), block_size());
auto first_block_of_bgdt = block_size() == 1024 ? 2 : 1;
auto buffer = UserOrKernelBuffer::for_kernel_buffer((u8*)block_group_descriptors());
if (auto result = write_blocks(first_block_of_bgdt, blocks_to_write, buffer); result.is_error())
dbgln("Ext2FS[{}]::flush_block_group_descriptor_table(): Failed to write blocks: {}", fsid(), result.error());
}
void Ext2FS::flush_writes()
{
{
MutexLocker locker(m_lock);
if (m_super_block_dirty) {
auto result = flush_super_block();
if (result.is_error()) {
dbgln("Ext2FS[{}]::flush_writes(): Failed to write superblock: {}", fsid(), result.error());
// FIXME: We should handle this error.
VERIFY_NOT_REACHED();
}
m_super_block_dirty = false;
}
if (m_block_group_descriptors_dirty) {
flush_block_group_descriptor_table();
m_block_group_descriptors_dirty = false;
}
for (auto& cached_bitmap : m_cached_bitmaps) {
if (cached_bitmap->dirty) {
auto buffer = UserOrKernelBuffer::for_kernel_buffer(cached_bitmap->buffer->data());
if (auto result = write_block(cached_bitmap->bitmap_block_index, buffer, block_size()); result.is_error()) {
dbgln("Ext2FS[{}]::flush_writes(): Failed to write blocks: {}", fsid(), result.error());
}
cached_bitmap->dirty = false;
dbgln_if(EXT2_DEBUG, "Ext2FS[{}]::flush_writes(): Flushed bitmap block {}", fsid(), cached_bitmap->bitmap_block_index);
}
}
// Uncache Inodes that are only kept alive by the index-to-inode lookup cache.
// We don't uncache Inodes that are being watched by at least one InodeWatcher.
// FIXME: It would be better to keep a capped number of Inodes around.
// The problem is that they are quite heavy objects, and use a lot of heap memory
// for their (child name lookup) and (block list) caches.
m_inode_cache.remove_all_matching([](InodeIndex, LockRefPtr<Ext2FSInode> const& cached_inode) {
// NOTE: If we're asked to look up an inode by number (via get_inode) and it turns out
// to not exist, we remember the fact that it doesn't exist by caching a nullptr.
// This seems like a reasonable time to uncache ideas about unknown inodes, so do that.
if (cached_inode == nullptr)
return true;
return cached_inode->ref_count() == 1 && !cached_inode->has_watchers();
});
}
BlockBasedFileSystem::flush_writes();
}
Ext2FSInode::Ext2FSInode(Ext2FS& fs, InodeIndex index)
: Inode(fs, index)
{
}
Ext2FSInode::~Ext2FSInode()
{
if (m_raw_inode.i_links_count == 0) {
// Alas, we have nowhere to propagate any errors that occur here.
(void)fs().free_inode(*this);
}
}
u64 Ext2FSInode::size() const
{
if (Kernel::is_regular_file(m_raw_inode.i_mode) && ((u32)fs().get_features_readonly() & (u32)Ext2FS::FeaturesReadOnly::FileSize64bits))
return static_cast<u64>(m_raw_inode.i_dir_acl) << 32 | m_raw_inode.i_size;
return m_raw_inode.i_size;
}
InodeMetadata Ext2FSInode::metadata() const
{
MutexLocker locker(m_inode_lock);
InodeMetadata metadata;
metadata.inode = identifier();
metadata.size = size();
metadata.mode = m_raw_inode.i_mode;
metadata.uid = m_raw_inode.i_uid;
metadata.gid = m_raw_inode.i_gid;
metadata.link_count = m_raw_inode.i_links_count;
metadata.atime = m_raw_inode.i_atime;
metadata.ctime = m_raw_inode.i_ctime;
metadata.mtime = m_raw_inode.i_mtime;
metadata.dtime = m_raw_inode.i_dtime;
metadata.block_size = fs().block_size();
metadata.block_count = m_raw_inode.i_blocks;
if (Kernel::is_character_device(m_raw_inode.i_mode) || Kernel::is_block_device(m_raw_inode.i_mode)) {
unsigned dev = m_raw_inode.i_block[0];
if (!dev)
dev = m_raw_inode.i_block[1];
metadata.major_device = (dev & 0xfff00) >> 8;
metadata.minor_device = (dev & 0xff) | ((dev >> 12) & 0xfff00);
}
return metadata;
}
ErrorOr<void> Ext2FSInode::flush_metadata()
{
MutexLocker locker(m_inode_lock);
dbgln_if(EXT2_DEBUG, "Ext2FSInode[{}]::flush_metadata(): Flushing inode", identifier());
TRY(fs().write_ext2_inode(index(), m_raw_inode));
if (is_directory()) {
// Unless we're about to go away permanently, invalidate the lookup cache.
if (m_raw_inode.i_links_count != 0) {
// FIXME: This invalidation is way too hardcore. It's sad to throw away the whole cache.
m_lookup_cache.clear();
}
}
set_metadata_dirty(false);
return {};
}
ErrorOr<NonnullLockRefPtr<Inode>> Ext2FS::get_inode(InodeIdentifier inode) const
{
MutexLocker locker(m_lock);
VERIFY(inode.fsid() == fsid());
{
auto it = m_inode_cache.find(inode.index());
if (it != m_inode_cache.end()) {
if (!it->value)
return ENOENT;
return NonnullLockRefPtr<Inode> { *it->value };
}
}
auto inode_allocation_state = TRY(get_inode_allocation_state(inode.index()));
if (!inode_allocation_state) {
TRY(m_inode_cache.try_set(inode.index(), nullptr));
return ENOENT;
}
BlockIndex block_index;
unsigned offset;
if (!find_block_containing_inode(inode.index(), block_index, offset))
return EINVAL;
auto new_inode = TRY(adopt_nonnull_lock_ref_or_enomem(new (nothrow) Ext2FSInode(const_cast<Ext2FS&>(*this), inode.index())));
auto buffer = UserOrKernelBuffer::for_kernel_buffer(reinterpret_cast<u8*>(&new_inode->m_raw_inode));
TRY(read_block(block_index, &buffer, sizeof(ext2_inode), offset));
TRY(m_inode_cache.try_set(inode.index(), new_inode));
return new_inode;
}
ErrorOr<size_t> Ext2FSInode::read_bytes(off_t offset, size_t count, UserOrKernelBuffer& buffer, OpenFileDescription* description) const
{
MutexLocker inode_locker(m_inode_lock);
VERIFY(offset >= 0);
if (m_raw_inode.i_size == 0)
return 0;
if (static_cast<u64>(offset) >= size())
return 0;
// Symbolic links shorter than 60 characters are store inline inside the i_block array.
// This avoids wasting an entire block on short links. (Most links are short.)
if (is_symlink() && size() < max_inline_symlink_length) {
VERIFY(offset == 0);
size_t nread = min((off_t)size() - offset, static_cast<off_t>(count));
TRY(buffer.write(((u8 const*)m_raw_inode.i_block) + offset, nread));
return nread;
}
if (m_block_list.is_empty())
m_block_list = TRY(compute_block_list());
if (m_block_list.is_empty()) {
dmesgln("Ext2FSInode[{}]::read_bytes(): Empty block list", identifier());
return EIO;
}
bool allow_cache = !description || !description->is_direct();
int const block_size = fs().block_size();
BlockBasedFileSystem::BlockIndex first_block_logical_index = offset / block_size;
BlockBasedFileSystem::BlockIndex last_block_logical_index = (offset + count) / block_size;
if (last_block_logical_index >= m_block_list.size())
last_block_logical_index = m_block_list.size() - 1;
int offset_into_first_block = offset % block_size;
size_t nread = 0;
auto remaining_count = min((off_t)count, (off_t)size() - offset);
dbgln_if(EXT2_VERY_DEBUG, "Ext2FSInode[{}]::read_bytes(): Reading up to {} bytes, {} bytes into inode to {}", identifier(), count, offset, buffer.user_or_kernel_ptr());
for (auto bi = first_block_logical_index; remaining_count && bi <= last_block_logical_index; bi = bi.value() + 1) {
auto block_index = m_block_list[bi.value()];
size_t offset_into_block = (bi == first_block_logical_index) ? offset_into_first_block : 0;
size_t num_bytes_to_copy = min((size_t)block_size - offset_into_block, (size_t)remaining_count);
auto buffer_offset = buffer.offset(nread);
if (block_index.value() == 0) {
// This is a hole, act as if it's filled with zeroes.
TRY(buffer_offset.memset(0, num_bytes_to_copy));
} else {
if (auto result = fs().read_block(block_index, &buffer_offset, num_bytes_to_copy, offset_into_block, allow_cache); result.is_error()) {
dmesgln("Ext2FSInode[{}]::read_bytes(): Failed to read block {} (index {})", identifier(), block_index.value(), bi);
return result.release_error();
}
}
remaining_count -= num_bytes_to_copy;
nread += num_bytes_to_copy;
}
return nread;
}
ErrorOr<void> Ext2FSInode::resize(u64 new_size)
{
auto old_size = size();
if (old_size == new_size)
return {};
if (!((u32)fs().get_features_readonly() & (u32)Ext2FS::FeaturesReadOnly::FileSize64bits) && (new_size >= static_cast<u32>(-1)))
return ENOSPC;
u64 block_size = fs().block_size();
auto blocks_needed_before = ceil_div(old_size, block_size);
auto blocks_needed_after = ceil_div(new_size, block_size);
if constexpr (EXT2_DEBUG) {
dbgln("Ext2FSInode[{}]::resize(): Blocks needed before (size was {}): {}", identifier(), old_size, blocks_needed_before);
dbgln("Ext2FSInode[{}]::resize(): Blocks needed after (size is {}): {}", identifier(), new_size, blocks_needed_after);
}
if (blocks_needed_after > blocks_needed_before) {
auto additional_blocks_needed = blocks_needed_after - blocks_needed_before;
if (additional_blocks_needed > fs().super_block().s_free_blocks_count)
return ENOSPC;
}
if (m_block_list.is_empty())
m_block_list = TRY(compute_block_list());
if (blocks_needed_after > blocks_needed_before) {
auto blocks = TRY(fs().allocate_blocks(fs().group_index_from_inode(index()), blocks_needed_after - blocks_needed_before));
TRY(m_block_list.try_extend(move(blocks)));
} else if (blocks_needed_after < blocks_needed_before) {
if constexpr (EXT2_VERY_DEBUG) {
dbgln("Ext2FSInode[{}]::resize(): Shrinking inode, old block list is {} entries:", identifier(), m_block_list.size());
for (auto block_index : m_block_list) {
dbgln(" # {}", block_index);
}
}
while (m_block_list.size() != blocks_needed_after) {
auto block_index = m_block_list.take_last();
if (block_index.value()) {
if (auto result = fs().set_block_allocation_state(block_index, false); result.is_error()) {
dbgln("Ext2FSInode[{}]::resize(): Failed to free block {}: {}", identifier(), block_index, result.error());
return result;
}
}
}
}
TRY(flush_block_list());
m_raw_inode.i_size = new_size;
if (Kernel::is_regular_file(m_raw_inode.i_mode))
m_raw_inode.i_dir_acl = new_size >> 32;
set_metadata_dirty(true);
if (new_size > old_size) {
// If we're growing the inode, make sure we zero out all the new space.
// FIXME: There are definitely more efficient ways to achieve this.
auto bytes_to_clear = new_size - old_size;
auto clear_from = old_size;
u8 zero_buffer[PAGE_SIZE] {};
while (bytes_to_clear) {
auto nwritten = TRY(write_bytes(clear_from, min(static_cast<u64>(sizeof(zero_buffer)), bytes_to_clear), UserOrKernelBuffer::for_kernel_buffer(zero_buffer), nullptr));
VERIFY(nwritten != 0);
bytes_to_clear -= nwritten;
clear_from += nwritten;
}
}
return {};
}
ErrorOr<size_t> Ext2FSInode::write_bytes(off_t offset, size_t count, UserOrKernelBuffer const& data, OpenFileDescription* description)
{
VERIFY(m_inode_lock.is_locked());
VERIFY(offset >= 0);
if (count == 0)
return 0;
if (is_symlink()) {
VERIFY(offset == 0);
if (max((size_t)(offset + count), (size_t)m_raw_inode.i_size) < max_inline_symlink_length) {
dbgln_if(EXT2_DEBUG, "Ext2FSInode[{}]::write_bytes(): Poking into i_block array for inline symlink ({} bytes)", identifier(), count);
TRY(data.read(((u8*)m_raw_inode.i_block) + offset, count));
if ((size_t)(offset + count) > (size_t)m_raw_inode.i_size)
m_raw_inode.i_size = offset + count;
set_metadata_dirty(true);
return count;
}
}
bool allow_cache = !description || !description->is_direct();
auto const block_size = fs().block_size();
auto new_size = max(static_cast<u64>(offset) + count, size());
TRY(resize(new_size));
if (m_block_list.is_empty())
m_block_list = TRY(compute_block_list());
if (m_block_list.is_empty()) {
dbgln("Ext2FSInode[{}]::write_bytes(): Empty block list", identifier());
return EIO;
}
BlockBasedFileSystem::BlockIndex first_block_logical_index = offset / block_size;
BlockBasedFileSystem::BlockIndex last_block_logical_index = (offset + count) / block_size;
if (last_block_logical_index >= m_block_list.size())
last_block_logical_index = m_block_list.size() - 1;
size_t offset_into_first_block = offset % block_size;
size_t nwritten = 0;
auto remaining_count = min((off_t)count, (off_t)new_size - offset);
dbgln_if(EXT2_VERY_DEBUG, "Ext2FSInode[{}]::write_bytes(): Writing {} bytes, {} bytes into inode from {}", identifier(), count, offset, data.user_or_kernel_ptr());
for (auto bi = first_block_logical_index; remaining_count && bi <= last_block_logical_index; bi = bi.value() + 1) {
size_t offset_into_block = (bi == first_block_logical_index) ? offset_into_first_block : 0;
size_t num_bytes_to_copy = min((size_t)block_size - offset_into_block, (size_t)remaining_count);
dbgln_if(EXT2_DEBUG, "Ext2FSInode[{}]::write_bytes(): Writing block {} (offset_into_block: {})", identifier(), m_block_list[bi.value()], offset_into_block);
if (auto result = fs().write_block(m_block_list[bi.value()], data.offset(nwritten), num_bytes_to_copy, offset_into_block, allow_cache); result.is_error()) {
dbgln("Ext2FSInode[{}]::write_bytes(): Failed to write block {} (index {})", identifier(), m_block_list[bi.value()], bi);
return result.release_error();
}
remaining_count -= num_bytes_to_copy;
nwritten += num_bytes_to_copy;
}
did_modify_contents();
dbgln_if(EXT2_VERY_DEBUG, "Ext2FSInode[{}]::write_bytes(): After write, i_size={}, i_blocks={} ({} blocks in list)", identifier(), size(), m_raw_inode.i_blocks, m_block_list.size());
return nwritten;
}
u8 Ext2FS::internal_file_type_to_directory_entry_type(DirectoryEntryView const& entry) const
{
switch (entry.file_type) {
case EXT2_FT_REG_FILE:
return DT_REG;
case EXT2_FT_DIR:
return DT_DIR;
case EXT2_FT_CHRDEV:
return DT_CHR;
case EXT2_FT_BLKDEV:
return DT_BLK;
case EXT2_FT_FIFO:
return DT_FIFO;
case EXT2_FT_SOCK:
return DT_SOCK;
case EXT2_FT_SYMLINK:
return DT_LNK;
default:
return DT_UNKNOWN;
}
}
Ext2FS::FeaturesReadOnly Ext2FS::get_features_readonly() const
{
if (m_super_block.s_rev_level > 0)
return static_cast<Ext2FS::FeaturesReadOnly>(m_super_block.s_feature_ro_compat);
return Ext2FS::FeaturesReadOnly::None;
}
ErrorOr<void> Ext2FSInode::traverse_as_directory(Function<ErrorOr<void>(FileSystem::DirectoryEntryView const&)> callback) const
{
VERIFY(is_directory());
u8 buffer[max_block_size];
auto buf = UserOrKernelBuffer::for_kernel_buffer(buffer);
auto block_size = fs().block_size();
auto file_size = size();
// Directory entries are guaranteed not to span multiple blocks,
// so we can iterate over blocks separately.
for (u64 offset = 0; offset < file_size; offset += block_size) {
TRY(read_bytes(offset, block_size, buf, nullptr));
auto* entry = reinterpret_cast<ext2_dir_entry_2*>(buffer);
auto* entries_end = reinterpret_cast<ext2_dir_entry_2*>(buffer + block_size);
while (entry < entries_end) {
if (entry->inode != 0) {
dbgln_if(EXT2_DEBUG, "Ext2FSInode[{}]::traverse_as_directory(): inode {}, name_len: {}, rec_len: {}, file_type: {}, name: {}", identifier(), entry->inode, entry->name_len, entry->rec_len, entry->file_type, StringView(entry->name, entry->name_len));
TRY(callback({ { entry->name, entry->name_len }, { fsid(), entry->inode }, entry->file_type }));
}
entry = (ext2_dir_entry_2*)((char*)entry + entry->rec_len);
}
}
return {};
}
ErrorOr<void> Ext2FSInode::write_directory(Vector<Ext2FSDirectoryEntry>& entries)
{
MutexLocker locker(m_inode_lock);
auto block_size = fs().block_size();
// Calculate directory size and record length of entries so that
// the following constraints are met:
// - All used blocks must be entirely filled.
// - Entries are aligned on a 4-byte boundary.
// - No entry may span multiple blocks.
size_t directory_size = 0;
size_t space_in_block = block_size;
for (size_t i = 0; i < entries.size(); ++i) {
auto& entry = entries[i];
entry.record_length = EXT2_DIR_REC_LEN(entry.name->length());
space_in_block -= entry.record_length;
if (i + 1 < entries.size()) {
if (EXT2_DIR_REC_LEN(entries[i + 1].name->length()) > space_in_block) {
entry.record_length += space_in_block;
space_in_block = block_size;
}
} else {
entry.record_length += space_in_block;
}
directory_size += entry.record_length;
}
dbgln_if(EXT2_DEBUG, "Ext2FSInode[{}]::write_directory(): New directory contents to write (size {}):", identifier(), directory_size);
auto directory_data = TRY(ByteBuffer::create_uninitialized(directory_size));
OutputMemoryStream stream { directory_data };
for (auto& entry : entries) {
dbgln_if(EXT2_DEBUG, "Ext2FSInode[{}]::write_directory(): Writing inode: {}, name_len: {}, rec_len: {}, file_type: {}, name: {}", identifier(), entry.inode_index, u16(entry.name->length()), u16(entry.record_length), u8(entry.file_type), entry.name);
stream << u32(entry.inode_index.value());
stream << u16(entry.record_length);
stream << u8(entry.name->length());
stream << u8(entry.file_type);
stream << entry.name->bytes();
int padding = entry.record_length - entry.name->length() - 8;
for (int j = 0; j < padding; ++j)
stream << u8(0);
}
VERIFY(stream.is_end());
TRY(resize(stream.size()));
auto buffer = UserOrKernelBuffer::for_kernel_buffer(stream.data());
auto nwritten = TRY(write_bytes(0, stream.size(), buffer, nullptr));
set_metadata_dirty(true);
if (nwritten != directory_data.size())
return EIO;
return {};
}
ErrorOr<NonnullLockRefPtr<Inode>> Ext2FSInode::create_child(StringView name, mode_t mode, dev_t dev, UserID uid, GroupID gid)
{
if (::is_directory(mode))
return fs().create_directory(*this, name, mode, uid, gid);
return fs().create_inode(*this, name, mode, dev, uid, gid);
}
ErrorOr<void> Ext2FSInode::add_child(Inode& child, StringView name, mode_t mode)
{
MutexLocker locker(m_inode_lock);
VERIFY(is_directory());
if (name.length() > EXT2_NAME_LEN)
return ENAMETOOLONG;
dbgln_if(EXT2_DEBUG, "Ext2FSInode[{}]::add_child(): Adding inode {} with name '{}' and mode {:o} to directory {}", identifier(), child.index(), name, mode, index());
Vector<Ext2FSDirectoryEntry> entries;
TRY(traverse_as_directory([&](auto& entry) -> ErrorOr<void> {
if (name == entry.name)
return EEXIST;
auto entry_name = TRY(KString::try_create(entry.name));
TRY(entries.try_append({ move(entry_name), entry.inode.index(), entry.file_type }));
return {};
}));
TRY(child.increment_link_count());
auto entry_name = TRY(KString::try_create(name));
TRY(entries.try_empend(move(entry_name), child.index(), to_ext2_file_type(mode)));
TRY(write_directory(entries));
TRY(populate_lookup_cache());
auto cache_entry_name = TRY(KString::try_create(name));
TRY(m_lookup_cache.try_set(move(cache_entry_name), child.index()));
did_add_child(child.identifier(), name);
return {};
}
ErrorOr<void> Ext2FSInode::remove_child(StringView name)
{
MutexLocker locker(m_inode_lock);
dbgln_if(EXT2_DEBUG, "Ext2FSInode[{}]::remove_child(): Removing '{}'", identifier(), name);
VERIFY(is_directory());
TRY(populate_lookup_cache());
auto it = m_lookup_cache.find(name);
if (it == m_lookup_cache.end())
return ENOENT;
auto child_inode_index = (*it).value;
InodeIdentifier child_id { fsid(), child_inode_index };
Vector<Ext2FSDirectoryEntry> entries;
TRY(traverse_as_directory([&](auto& entry) -> ErrorOr<void> {
if (name != entry.name) {
auto entry_name = TRY(KString::try_create(entry.name));
TRY(entries.try_append({ move(entry_name), entry.inode.index(), entry.file_type }));
}
return {};
}));
TRY(write_directory(entries));
m_lookup_cache.remove(it);
auto child_inode = TRY(fs().get_inode(child_id));
TRY(child_inode->decrement_link_count());
did_remove_child(child_id, name);
return {};
}
u64 Ext2FS::inodes_per_block() const
{
return EXT2_INODES_PER_BLOCK(&super_block());
}
u64 Ext2FS::inodes_per_group() const
{
return EXT2_INODES_PER_GROUP(&super_block());
}
u64 Ext2FS::inode_size() const
{
return EXT2_INODE_SIZE(&super_block());
}
u64 Ext2FS::blocks_per_group() const
{
return EXT2_BLOCKS_PER_GROUP(&super_block());
}
ErrorOr<void> Ext2FS::write_ext2_inode(InodeIndex inode, ext2_inode const& e2inode)
{
BlockIndex block_index;
unsigned offset;
if (!find_block_containing_inode(inode, block_index, offset))
return EINVAL;
auto buffer = UserOrKernelBuffer::for_kernel_buffer(const_cast<u8*>((u8 const*)&e2inode));
return write_block(block_index, buffer, inode_size(), offset);
}
auto Ext2FS::allocate_blocks(GroupIndex preferred_group_index, size_t count) -> ErrorOr<Vector<BlockIndex>>
{
dbgln_if(EXT2_DEBUG, "Ext2FS: allocate_blocks(preferred group: {}, count {})", preferred_group_index, count);
if (count == 0)
return Vector<BlockIndex> {};
Vector<BlockIndex> blocks;
TRY(blocks.try_ensure_capacity(count));
MutexLocker locker(m_lock);
auto group_index = preferred_group_index;
if (!group_descriptor(preferred_group_index).bg_free_blocks_count) {
group_index = 1;
}
while (blocks.size() < count) {
bool found_a_group = false;
if (group_descriptor(group_index).bg_free_blocks_count) {
found_a_group = true;
} else {
if (group_index == preferred_group_index)
group_index = 1;
for (; group_index <= m_block_group_count; group_index = GroupIndex { group_index.value() + 1 }) {
if (group_descriptor(group_index).bg_free_blocks_count) {
found_a_group = true;
break;
}
}
}
VERIFY(found_a_group);
auto const& bgd = group_descriptor(group_index);
auto* cached_bitmap = TRY(get_bitmap_block(bgd.bg_block_bitmap));
int blocks_in_group = min(blocks_per_group(), super_block().s_blocks_count);
auto block_bitmap = cached_bitmap->bitmap(blocks_in_group);
BlockIndex first_block_in_group = (group_index.value() - 1) * blocks_per_group() + first_block_index().value();
size_t free_region_size = 0;
auto first_unset_bit_index = block_bitmap.find_longest_range_of_unset_bits(count - blocks.size(), free_region_size);
VERIFY(first_unset_bit_index.has_value());
dbgln_if(EXT2_DEBUG, "Ext2FS: allocating free region of size: {} [{}]", free_region_size, group_index);
for (size_t i = 0; i < free_region_size; ++i) {
BlockIndex block_index = (first_unset_bit_index.value() + i) + first_block_in_group.value();
TRY(set_block_allocation_state(block_index, true));
blocks.unchecked_append(block_index);
dbgln_if(EXT2_DEBUG, " allocated > {}", block_index);
}
}
VERIFY(blocks.size() == count);
return blocks;
}
ErrorOr<InodeIndex> Ext2FS::allocate_inode(GroupIndex preferred_group)
{
dbgln_if(EXT2_DEBUG, "Ext2FS: allocate_inode(preferred_group: {})", preferred_group);
MutexLocker locker(m_lock);
// FIXME: We shouldn't refuse to allocate an inode if there is no group that can house the whole thing.
// In those cases we should just spread it across multiple groups.
auto is_suitable_group = [this](auto group_index) {
auto& bgd = group_descriptor(group_index);
return bgd.bg_free_inodes_count && bgd.bg_free_blocks_count >= 1;
};
GroupIndex group_index;
if (preferred_group.value() && is_suitable_group(preferred_group)) {
group_index = preferred_group;
} else {
for (unsigned i = 1; i <= m_block_group_count; ++i) {
if (is_suitable_group(i)) {
group_index = i;
break;
}
}
}
if (!group_index) {
dmesgln("Ext2FS: allocate_inode: no suitable group found for new inode");
return ENOSPC;
}
dbgln_if(EXT2_DEBUG, "Ext2FS: allocate_inode: found suitable group [{}] for new inode :^)", group_index);
auto const& bgd = group_descriptor(group_index);
unsigned inodes_in_group = min(inodes_per_group(), super_block().s_inodes_count);
InodeIndex first_inode_in_group = (group_index.value() - 1) * inodes_per_group() + 1;
auto* cached_bitmap = TRY(get_bitmap_block(bgd.bg_inode_bitmap));
auto inode_bitmap = cached_bitmap->bitmap(inodes_in_group);
for (size_t i = 0; i < inode_bitmap.size(); ++i) {
if (inode_bitmap.get(i))
continue;
inode_bitmap.set(i, true);
auto inode_index = InodeIndex(first_inode_in_group.value() + i);
cached_bitmap->dirty = true;
m_super_block.s_free_inodes_count--;
m_super_block_dirty = true;
const_cast<ext2_group_desc&>(bgd).bg_free_inodes_count--;
m_block_group_descriptors_dirty = true;
// In case the inode cache had this cached as "non-existent", uncache that info.
m_inode_cache.remove(inode_index.value());
return inode_index;
}
dmesgln("Ext2FS: allocate_inode found no available inode, despite bgd claiming there are inodes :(");
return EIO;
}
Ext2FS::GroupIndex Ext2FS::group_index_from_block_index(BlockIndex block_index) const
{
if (!block_index)
return 0;
return (block_index.value() - 1) / blocks_per_group() + 1;
}
auto Ext2FS::group_index_from_inode(InodeIndex inode) const -> GroupIndex
{
if (!inode)
return 0;
return (inode.value() - 1) / inodes_per_group() + 1;
}
ErrorOr<bool> Ext2FS::get_inode_allocation_state(InodeIndex index) const
{
MutexLocker locker(m_lock);
if (index == 0)
return EINVAL;
auto group_index = group_index_from_inode(index);
auto const& bgd = group_descriptor(group_index);
unsigned index_in_group = index.value() - ((group_index.value() - 1) * inodes_per_group());
unsigned bit_index = (index_in_group - 1) % inodes_per_group();
auto* cached_bitmap = TRY(const_cast<Ext2FS&>(*this).get_bitmap_block(bgd.bg_inode_bitmap));
return cached_bitmap->bitmap(inodes_per_group()).get(bit_index);
}
ErrorOr<void> Ext2FS::update_bitmap_block(BlockIndex bitmap_block, size_t bit_index, bool new_state, u32& super_block_counter, u16& group_descriptor_counter)
{
auto* cached_bitmap = TRY(get_bitmap_block(bitmap_block));
bool current_state = cached_bitmap->bitmap(blocks_per_group()).get(bit_index);
if (current_state == new_state) {
dbgln("Ext2FS: Bit {} in bitmap block {} had unexpected state {}", bit_index, bitmap_block, current_state);
return EIO;
}
cached_bitmap->bitmap(blocks_per_group()).set(bit_index, new_state);
cached_bitmap->dirty = true;
if (new_state) {
--super_block_counter;
--group_descriptor_counter;
} else {
++super_block_counter;
++group_descriptor_counter;
}
m_super_block_dirty = true;
m_block_group_descriptors_dirty = true;
return {};
}
ErrorOr<void> Ext2FS::set_inode_allocation_state(InodeIndex inode_index, bool new_state)
{
MutexLocker locker(m_lock);
auto group_index = group_index_from_inode(inode_index);
unsigned index_in_group = inode_index.value() - ((group_index.value() - 1) * inodes_per_group());
unsigned bit_index = (index_in_group - 1) % inodes_per_group();
dbgln_if(EXT2_DEBUG, "Ext2FS: set_inode_allocation_state: Inode {} -> {}", inode_index, new_state);
auto& bgd = const_cast<ext2_group_desc&>(group_descriptor(group_index));
return update_bitmap_block(bgd.bg_inode_bitmap, bit_index, new_state, m_super_block.s_free_inodes_count, bgd.bg_free_inodes_count);
}
Ext2FS::BlockIndex Ext2FS::first_block_index() const
{
return block_size() == 1024 ? 1 : 0;
}
ErrorOr<Ext2FS::CachedBitmap*> Ext2FS::get_bitmap_block(BlockIndex bitmap_block_index)
{
for (auto& cached_bitmap : m_cached_bitmaps) {
if (cached_bitmap->bitmap_block_index == bitmap_block_index)
return cached_bitmap.ptr();
}
auto block = TRY(KBuffer::try_create_with_size("Ext2FS: Cached bitmap block"sv, block_size(), Memory::Region::Access::ReadWrite));
auto buffer = UserOrKernelBuffer::for_kernel_buffer(block->data());
TRY(read_block(bitmap_block_index, &buffer, block_size()));
auto new_bitmap = TRY(adopt_nonnull_own_or_enomem(new (nothrow) CachedBitmap(bitmap_block_index, move(block))));
TRY(m_cached_bitmaps.try_append(move(new_bitmap)));
return m_cached_bitmaps.last().ptr();
}
ErrorOr<void> Ext2FS::set_block_allocation_state(BlockIndex block_index, bool new_state)
{
VERIFY(block_index != 0);
MutexLocker locker(m_lock);
auto group_index = group_index_from_block_index(block_index);
unsigned index_in_group = (block_index.value() - first_block_index().value()) - ((group_index.value() - 1) * blocks_per_group());
unsigned bit_index = index_in_group % blocks_per_group();
auto& bgd = const_cast<ext2_group_desc&>(group_descriptor(group_index));
dbgln_if(EXT2_DEBUG, "Ext2FS: Block {} state -> {} (in bitmap block {})", block_index, new_state, bgd.bg_block_bitmap);
return update_bitmap_block(bgd.bg_block_bitmap, bit_index, new_state, m_super_block.s_free_blocks_count, bgd.bg_free_blocks_count);
}
ErrorOr<NonnullLockRefPtr<Inode>> Ext2FS::create_directory(Ext2FSInode& parent_inode, StringView name, mode_t mode, UserID uid, GroupID gid)
{
MutexLocker locker(m_lock);
VERIFY(is_directory(mode));
auto inode = TRY(create_inode(parent_inode, name, mode, 0, uid, gid));
dbgln_if(EXT2_DEBUG, "Ext2FS: create_directory: created new directory named '{} with inode {}", name, inode->index());
Vector<Ext2FSDirectoryEntry> entries;
auto current_directory_name = TRY(KString::try_create("."sv));
TRY(entries.try_empend(move(current_directory_name), inode->index(), static_cast<u8>(EXT2_FT_DIR)));
auto parent_directory_name = TRY(KString::try_create(".."sv));
TRY(entries.try_empend(move(parent_directory_name), parent_inode.index(), static_cast<u8>(EXT2_FT_DIR)));
TRY(static_cast<Ext2FSInode&>(*inode).write_directory(entries));
TRY(parent_inode.increment_link_count());
auto& bgd = const_cast<ext2_group_desc&>(group_descriptor(group_index_from_inode(inode->identifier().index())));
++bgd.bg_used_dirs_count;
m_block_group_descriptors_dirty = true;
return inode;
}
ErrorOr<NonnullLockRefPtr<Inode>> Ext2FS::create_inode(Ext2FSInode& parent_inode, StringView name, mode_t mode, dev_t dev, UserID uid, GroupID gid)
{
if (name.length() > EXT2_NAME_LEN)
return ENAMETOOLONG;
if (parent_inode.m_raw_inode.i_links_count == 0)
return ENOENT;
ext2_inode e2inode {};
auto now = kgettimeofday().to_truncated_seconds();
e2inode.i_mode = mode;
e2inode.i_uid = uid.value();
e2inode.i_gid = gid.value();
e2inode.i_size = 0;
e2inode.i_atime = now;
e2inode.i_ctime = now;
e2inode.i_mtime = now;
e2inode.i_dtime = 0;
e2inode.i_flags = 0;
// For directories, add +1 link count for the "." entry in self.
e2inode.i_links_count = is_directory(mode);
if (is_character_device(mode))
e2inode.i_block[0] = dev;
else if (is_block_device(mode))
e2inode.i_block[1] = dev;
auto inode_id = TRY(allocate_inode());
dbgln_if(EXT2_DEBUG, "Ext2FS: writing initial metadata for inode {}", inode_id.value());
TRY(write_ext2_inode(inode_id, e2inode));
auto new_inode = TRY(get_inode({ fsid(), inode_id }));
dbgln_if(EXT2_DEBUG, "Ext2FS: Adding inode '{}' (mode {:o}) to parent directory {}", name, mode, parent_inode.index());
TRY(parent_inode.add_child(*new_inode, name, mode));
return new_inode;
}
ErrorOr<void> Ext2FSInode::populate_lookup_cache() const
{
MutexLocker locker(m_inode_lock);
if (!m_lookup_cache.is_empty())
return {};
HashMap<NonnullOwnPtr<KString>, InodeIndex> children;
TRY(traverse_as_directory([&children](auto& entry) -> ErrorOr<void> {
auto entry_name = TRY(KString::try_create(entry.name));
TRY(children.try_set(move(entry_name), entry.inode.index()));
return {};
}));
VERIFY(m_lookup_cache.is_empty());
m_lookup_cache = move(children);
return {};
}
ErrorOr<NonnullLockRefPtr<Inode>> Ext2FSInode::lookup(StringView name)
{
VERIFY(is_directory());
dbgln_if(EXT2_DEBUG, "Ext2FSInode[{}]:lookup(): Looking up '{}'", identifier(), name);
TRY(populate_lookup_cache());
InodeIndex inode_index;
{
MutexLocker locker(m_inode_lock);
auto it = m_lookup_cache.find(name);
if (it == m_lookup_cache.end()) {
dbgln_if(EXT2_DEBUG, "Ext2FSInode[{}]:lookup(): '{}' not found", identifier(), name);
return ENOENT;
}
inode_index = it->value;
}
return fs().get_inode({ fsid(), inode_index });
}
ErrorOr<void> Ext2FSInode::update_timestamps(Optional<time_t> atime, Optional<time_t> ctime, Optional<time_t> mtime)
{
MutexLocker locker(m_inode_lock);
if (fs().is_readonly())
return EROFS;
if (atime.value_or(0) > INT32_MAX)
return EINVAL;
if (ctime.value_or(0) > INT32_MAX)
return EINVAL;
if (mtime.value_or(0) > INT32_MAX)
return EINVAL;
if (atime.has_value())
m_raw_inode.i_atime = atime.value();
if (ctime.has_value())
m_raw_inode.i_ctime = ctime.value();
if (mtime.has_value())
m_raw_inode.i_mtime = mtime.value();
set_metadata_dirty(true);
return {};
}
ErrorOr<void> Ext2FSInode::increment_link_count()
{
MutexLocker locker(m_inode_lock);
if (fs().is_readonly())
return EROFS;
constexpr size_t max_link_count = 65535;
if (m_raw_inode.i_links_count == max_link_count)
return EMLINK;
++m_raw_inode.i_links_count;
set_metadata_dirty(true);
return {};
}
ErrorOr<void> Ext2FSInode::decrement_link_count()
{
MutexLocker locker(m_inode_lock);
if (fs().is_readonly())
return EROFS;
VERIFY(m_raw_inode.i_links_count);
--m_raw_inode.i_links_count;
set_metadata_dirty(true);
if (m_raw_inode.i_links_count == 0)
did_delete_self();
if (ref_count() == 1 && m_raw_inode.i_links_count == 0)
fs().uncache_inode(index());
return {};
}
void Ext2FS::uncache_inode(InodeIndex index)
{
MutexLocker locker(m_lock);
m_inode_cache.remove(index);
}
ErrorOr<void> Ext2FSInode::chmod(mode_t mode)
{
MutexLocker locker(m_inode_lock);
if (m_raw_inode.i_mode == mode)
return {};
m_raw_inode.i_mode = mode;
set_metadata_dirty(true);
return {};
}
ErrorOr<void> Ext2FSInode::chown(UserID uid, GroupID gid)
{
MutexLocker locker(m_inode_lock);
if (m_raw_inode.i_uid == uid && m_raw_inode.i_gid == gid)
return {};
m_raw_inode.i_uid = uid.value();
m_raw_inode.i_gid = gid.value();
set_metadata_dirty(true);
return {};
}
ErrorOr<void> Ext2FSInode::truncate(u64 size)
{
MutexLocker locker(m_inode_lock);
if (static_cast<u64>(m_raw_inode.i_size) == size)
return {};
TRY(resize(size));
set_metadata_dirty(true);
return {};
}
ErrorOr<int> Ext2FSInode::get_block_address(int index)
{
MutexLocker locker(m_inode_lock);
if (m_block_list.is_empty())
m_block_list = TRY(compute_block_list());
if (index < 0 || (size_t)index >= m_block_list.size())
return 0;
return m_block_list[index].value();
}
unsigned Ext2FS::total_block_count() const
{
MutexLocker locker(m_lock);
return super_block().s_blocks_count;
}
unsigned Ext2FS::free_block_count() const
{
MutexLocker locker(m_lock);
return super_block().s_free_blocks_count;
}
unsigned Ext2FS::total_inode_count() const
{
MutexLocker locker(m_lock);
return super_block().s_inodes_count;
}
unsigned Ext2FS::free_inode_count() const
{
MutexLocker locker(m_lock);
return super_block().s_free_inodes_count;
}
ErrorOr<void> Ext2FS::prepare_to_unmount()
{
MutexLocker locker(m_lock);
for (auto& it : m_inode_cache) {
if (it.value->ref_count() > 1)
return EBUSY;
}
m_inode_cache.clear();
m_root_inode = nullptr;
return {};
}
}
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