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serenity/Kernel/FileSystem/Ext2FS/Inode.cpp
implicitfield 54bfc3d294 Kernel/Ext2FS: Cache blocks less aggressively 
With this patch, we now only cache at most 2^14 blocks, which greatly
relieves memory pressure when working with large files.
2024-11-05 20:14:21 +01:00

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41 KiB
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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/IntegralMath.h>
#include <AK/IterationDecision.h>
#include <AK/MemoryStream.h>
#include <Kernel/API/POSIX/errno.h>
#include <Kernel/Debug.h>
#include <Kernel/FileSystem/Ext2FS/FileSystem.h>
#include <Kernel/FileSystem/Ext2FS/Inode.h>
#include <Kernel/FileSystem/InodeMetadata.h>
#include <Kernel/UnixTypes.h>
namespace Kernel {
static constexpr size_t max_inline_symlink_length = 60;
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<void> Ext2FSInode::write_singly_indirect_block_pointer(BlockBasedFileSystem::BlockIndex logical_block_index, BlockBasedFileSystem::BlockIndex on_disk_index)
{
auto const entries_per_block = EXT2_ADDR_PER_BLOCK(&fs().super_block());
auto const block_size = fs().logical_block_size();
auto offset_in_block = logical_block_index.value() - EXT2_IND_BLOCK;
auto singly_indirect_block_storage = TRY(ByteBuffer::create_zeroed(block_size));
auto singly_indirect_block_contents = Span<u32> { bit_cast<u32*>(singly_indirect_block_storage.data()), entries_per_block };
auto singly_indirect_block_buffer = UserOrKernelBuffer::for_kernel_buffer(singly_indirect_block_storage.data());
if (m_raw_inode.i_block[EXT2_IND_BLOCK] == 0) [[unlikely]] {
m_raw_inode.i_block[EXT2_IND_BLOCK] = TRY(allocate_and_zero_block());
set_metadata_dirty(true);
}
TRY(fs().read_block(m_raw_inode.i_block[EXT2_IND_BLOCK], &singly_indirect_block_buffer, block_size, 0));
singly_indirect_block_contents[offset_in_block] = on_disk_index.value();
TRY(fs().write_block(m_raw_inode.i_block[EXT2_IND_BLOCK], singly_indirect_block_buffer, block_size));
if (on_disk_index != 0)
return {};
if (!singly_indirect_block_contents.filled_with(0))
return {};
TRY(fs().set_block_allocation_state(m_raw_inode.i_block[EXT2_IND_BLOCK], false));
m_raw_inode.i_block[EXT2_IND_BLOCK] = 0;
m_raw_inode.i_blocks -= fs().i_blocks_increment();
set_metadata_dirty(true);
return {};
}
ErrorOr<void> Ext2FSInode::write_doubly_indirect_block_pointer(BlockBasedFileSystem::BlockIndex logical_block_index, BlockBasedFileSystem::BlockIndex on_disk_index)
{
auto const entries_per_block = EXT2_ADDR_PER_BLOCK(&fs().super_block());
auto const block_size = fs().logical_block_size();
auto const offset = logical_block_index.value() - singly_indirect_block_capacity();
auto const offset_in_doubly_indirect_block = offset / entries_per_block;
auto const offset_in_singly_indirect_block = offset % entries_per_block;
auto doubly_indirect_block_storage = TRY(ByteBuffer::create_zeroed(block_size));
auto doubly_indirect_block_contents = Span<u32> { bit_cast<u32*>(doubly_indirect_block_storage.data()), entries_per_block };
auto doubly_indirect_block_buffer = UserOrKernelBuffer::for_kernel_buffer(doubly_indirect_block_storage.data());
auto singly_indirect_block_storage = TRY(ByteBuffer::create_zeroed(block_size));
auto singly_indirect_block_contents = Span<u32> { bit_cast<u32*>(singly_indirect_block_storage.data()), entries_per_block };
auto singly_indirect_block_buffer = UserOrKernelBuffer::for_kernel_buffer(singly_indirect_block_storage.data());
if (m_raw_inode.i_block[EXT2_DIND_BLOCK] == 0) [[unlikely]] {
m_raw_inode.i_block[EXT2_DIND_BLOCK] = TRY(allocate_and_zero_block());
set_metadata_dirty(true);
}
TRY(fs().read_block(m_raw_inode.i_block[EXT2_DIND_BLOCK], &doubly_indirect_block_buffer, block_size, 0));
if (doubly_indirect_block_contents[offset_in_doubly_indirect_block] == 0) [[unlikely]] {
doubly_indirect_block_contents[offset_in_doubly_indirect_block] = TRY(allocate_and_zero_block());
TRY(fs().write_block(m_raw_inode.i_block[EXT2_DIND_BLOCK], doubly_indirect_block_buffer, block_size));
}
TRY(fs().read_block(doubly_indirect_block_contents[offset_in_doubly_indirect_block], &singly_indirect_block_buffer, block_size, 0));
singly_indirect_block_contents[offset_in_singly_indirect_block] = on_disk_index.value();
TRY(fs().write_block(doubly_indirect_block_contents[offset_in_doubly_indirect_block], singly_indirect_block_buffer, block_size));
if (on_disk_index != 0)
return {};
if (!singly_indirect_block_contents.filled_with(0))
return {};
TRY(fs().set_block_allocation_state(doubly_indirect_block_contents[offset_in_doubly_indirect_block], false));
doubly_indirect_block_contents[offset_in_doubly_indirect_block] = 0;
m_raw_inode.i_blocks -= fs().i_blocks_increment();
TRY(fs().write_block(m_raw_inode.i_block[EXT2_DIND_BLOCK], doubly_indirect_block_buffer, block_size));
if (!doubly_indirect_block_contents.filled_with(0))
return {};
TRY(fs().set_block_allocation_state(m_raw_inode.i_block[EXT2_DIND_BLOCK], false));
m_raw_inode.i_block[EXT2_DIND_BLOCK] = 0;
m_raw_inode.i_blocks -= fs().i_blocks_increment();
set_metadata_dirty(true);
return {};
}
ErrorOr<void> Ext2FSInode::write_triply_indirect_block_pointer(BlockBasedFileSystem::BlockIndex logical_block_index, BlockBasedFileSystem::BlockIndex on_disk_index)
{
auto const entries_per_block = EXT2_ADDR_PER_BLOCK(&fs().super_block());
auto const block_size = fs().logical_block_size();
auto const offset = logical_block_index.value() - doubly_indirect_block_capacity();
auto const offset_in_triply_indirect_block = offset / (entries_per_block * entries_per_block);
auto const skipped_blocks = entries_per_block * entries_per_block * offset_in_triply_indirect_block;
auto const offset_in_doubly_indirect_block = (offset - skipped_blocks) / entries_per_block;
auto const offset_in_singly_indirect_block = offset % entries_per_block;
auto triply_indirect_block_storage = TRY(ByteBuffer::create_zeroed(block_size));
auto triply_indirect_block_contents = Span<u32> { bit_cast<u32*>(triply_indirect_block_storage.data()), entries_per_block };
auto triply_indirect_block_buffer = UserOrKernelBuffer::for_kernel_buffer(triply_indirect_block_storage.data());
auto doubly_indirect_block_storage = TRY(ByteBuffer::create_zeroed(block_size));
auto doubly_indirect_block_contents = Span<u32> { bit_cast<u32*>(doubly_indirect_block_storage.data()), entries_per_block };
auto doubly_indirect_block_buffer = UserOrKernelBuffer::for_kernel_buffer(doubly_indirect_block_storage.data());
auto singly_indirect_block_storage = TRY(ByteBuffer::create_zeroed(block_size));
auto singly_indirect_block_contents = Span<u32> { bit_cast<u32*>(singly_indirect_block_storage.data()), entries_per_block };
auto singly_indirect_block_buffer = UserOrKernelBuffer::for_kernel_buffer(singly_indirect_block_storage.data());
if (m_raw_inode.i_block[EXT2_TIND_BLOCK] == 0) [[unlikely]] {
m_raw_inode.i_block[EXT2_TIND_BLOCK] = TRY(allocate_and_zero_block());
set_metadata_dirty(true);
}
TRY(fs().read_block(m_raw_inode.i_block[EXT2_TIND_BLOCK], &triply_indirect_block_buffer, block_size, 0));
if (triply_indirect_block_contents[offset_in_triply_indirect_block] == 0) [[unlikely]] {
triply_indirect_block_contents[offset_in_triply_indirect_block] = TRY(allocate_and_zero_block());
TRY(fs().write_block(m_raw_inode.i_block[EXT2_TIND_BLOCK], triply_indirect_block_buffer, block_size));
}
TRY(fs().read_block(triply_indirect_block_contents[offset_in_triply_indirect_block], &doubly_indirect_block_buffer, block_size, 0));
if (doubly_indirect_block_contents[offset_in_doubly_indirect_block] == 0) [[unlikely]] {
doubly_indirect_block_contents[offset_in_doubly_indirect_block] = TRY(allocate_and_zero_block());
TRY(fs().write_block(triply_indirect_block_contents[offset_in_triply_indirect_block], doubly_indirect_block_buffer, block_size));
}
TRY(fs().read_block(doubly_indirect_block_contents[offset_in_doubly_indirect_block], &singly_indirect_block_buffer, block_size, 0));
singly_indirect_block_contents[offset_in_singly_indirect_block] = on_disk_index.value();
TRY(fs().write_block(doubly_indirect_block_contents[offset_in_doubly_indirect_block], singly_indirect_block_buffer, block_size));
if (on_disk_index != 0)
return {};
if (!singly_indirect_block_contents.filled_with(0))
return {};
TRY(fs().set_block_allocation_state(doubly_indirect_block_contents[offset_in_doubly_indirect_block], false));
doubly_indirect_block_contents[offset_in_doubly_indirect_block] = 0;
m_raw_inode.i_blocks -= fs().i_blocks_increment();
TRY(fs().write_block(triply_indirect_block_contents[offset_in_triply_indirect_block], doubly_indirect_block_buffer, block_size));
if (!doubly_indirect_block_contents.filled_with(0))
return {};
TRY(fs().set_block_allocation_state(triply_indirect_block_contents[offset_in_triply_indirect_block], false));
triply_indirect_block_contents[offset_in_triply_indirect_block] = 0;
m_raw_inode.i_blocks -= fs().i_blocks_increment();
TRY(fs().write_block(m_raw_inode.i_block[EXT2_TIND_BLOCK], triply_indirect_block_buffer, block_size));
if (!triply_indirect_block_contents.filled_with(0))
return {};
TRY(fs().set_block_allocation_state(m_raw_inode.i_block[EXT2_TIND_BLOCK], false));
m_raw_inode.i_block[EXT2_TIND_BLOCK] = 0;
m_raw_inode.i_blocks -= fs().i_blocks_increment();
set_metadata_dirty(true);
return {};
}
ErrorOr<u32> Ext2FSInode::allocate_and_zero_block()
{
auto const block_size = fs().logical_block_size();
auto blocks = TRY(fs().allocate_blocks(fs().group_index_from_inode(index()), 1));
m_raw_inode.i_blocks += fs().i_blocks_increment();
auto block = blocks.first();
auto buffer_content = TRY(ByteBuffer::create_zeroed(block_size));
TRY(fs().write_block(block, UserOrKernelBuffer::for_kernel_buffer(buffer_content.data()), block_size));
return block.value();
}
ErrorOr<void> Ext2FSInode::write_block_pointer(BlockBasedFileSystem::BlockIndex logical_block_index, BlockBasedFileSystem::BlockIndex on_disk_index)
{
VERIFY(m_inode_lock.is_locked());
if (logical_block_index < EXT2_NDIR_BLOCKS) {
if (m_raw_inode.i_block[logical_block_index.value()] != on_disk_index) {
m_raw_inode.i_block[logical_block_index.value()] = on_disk_index.value();
set_metadata_dirty(true);
}
return {};
}
if (logical_block_index < singly_indirect_block_capacity())
return write_singly_indirect_block_pointer(logical_block_index, on_disk_index);
if (logical_block_index < doubly_indirect_block_capacity())
return write_doubly_indirect_block_pointer(logical_block_index, on_disk_index);
if (logical_block_index < triply_indirect_block_capacity())
return write_triply_indirect_block_pointer(logical_block_index, on_disk_index);
VERIFY_NOT_REACHED();
}
ErrorOr<Ext2FS::BlockList> Ext2FSInode::compute_block_list(BlockBasedFileSystem::BlockIndex first_block, BlockBasedFileSystem::BlockIndex last_block) const
{
dbgln_if(EXT2_DEBUG, "Ext2FSInode[{}]::block_list_for_inode(): i_size={}, i_blocks={}", identifier(), m_raw_inode.i_size, m_raw_inode.i_blocks);
Ext2FS::BlockList list {};
// 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 (Kernel::is_symlink(m_raw_inode.i_mode) && m_raw_inode.i_blocks == 0)
return list;
unsigned const block_size = fs().logical_block_size();
unsigned const entries_per_block = EXT2_ADDR_PER_BLOCK(&fs().super_block());
auto set_block = [&](auto logical_index, auto on_disk_index) -> ErrorOr<IterationDecision> {
if (logical_index < first_block)
return IterationDecision::Continue;
if (logical_index > last_block)
return IterationDecision::Break;
TRY(list.try_set(logical_index, on_disk_index));
return IterationDecision::Continue;
};
auto process_block_array = [&](auto current_logical_index, unsigned level, auto array_block_index, ByteBuffer& array_storage, auto&& callback) -> ErrorOr<IterationDecision> {
TRY(array_storage.try_resize(block_size));
auto* array = (u32*)array_storage.data();
auto buffer = UserOrKernelBuffer::for_kernel_buffer((u8*)array);
TRY(fs().read_block(array_block_index, &buffer, block_size, 0));
for (unsigned i = 0; i < block_size / sizeof(u32); ++i) {
if (array[i] != 0) {
if (TRY(callback(current_logical_index + i * AK::pow(entries_per_block, level - 1), array[i])) == IterationDecision::Break)
return IterationDecision::Break;
}
}
return IterationDecision::Continue;
};
if (first_block < EXT2_NDIR_BLOCKS) {
for (size_t i = 0; i < EXT2_NDIR_BLOCKS; ++i) {
if (m_raw_inode.i_block[i] != 0)
TRY(set_block(i, m_raw_inode.i_block[i]));
}
}
ByteBuffer block_storage[3] = {};
if (first_block < singly_indirect_block_capacity() && m_raw_inode.i_block[EXT2_IND_BLOCK]) {
TRY(process_block_array(EXT2_NDIR_BLOCKS, 1, m_raw_inode.i_block[EXT2_IND_BLOCK], block_storage[0], [&](auto logical_block_index, auto on_disk_index) -> ErrorOr<IterationDecision> {
return set_block(logical_block_index, on_disk_index);
}));
}
if (first_block < doubly_indirect_block_capacity() && m_raw_inode.i_block[EXT2_DIND_BLOCK]) {
TRY(process_block_array(singly_indirect_block_capacity(), 2, m_raw_inode.i_block[EXT2_DIND_BLOCK], block_storage[1], [&](auto logical_block_index, auto on_disk_index) -> ErrorOr<IterationDecision> {
return process_block_array(logical_block_index, 1, on_disk_index, block_storage[0], [&](auto logical_block_index2, auto on_disk_index2) -> ErrorOr<IterationDecision> {
return set_block(logical_block_index2, on_disk_index2);
});
}));
}
if (first_block < triply_indirect_block_capacity() && m_raw_inode.i_block[EXT2_TIND_BLOCK]) {
TRY(process_block_array(doubly_indirect_block_capacity(), 3, m_raw_inode.i_block[EXT2_TIND_BLOCK], block_storage[2], [&](auto logical_block_index, auto on_disk_index) -> ErrorOr<IterationDecision> {
return process_block_array(logical_block_index, 2, on_disk_index, block_storage[1], [&](auto logical_block_index2, auto on_disk_index2) -> ErrorOr<IterationDecision> {
return process_block_array(logical_block_index2, 1, on_disk_index2, block_storage[0], [&](auto logical_block_index3, auto on_disk_index3) -> ErrorOr<IterationDecision> {
return set_block(logical_block_index3, on_disk_index3);
});
});
}));
}
return list;
}
ErrorOr<void> Ext2FSInode::free_all_blocks()
{
MutexLocker locker(m_inode_lock);
dbgln_if(EXT2_DEBUG, "Ext2FSInode[{}]::free_all_blocks(): i_size={}, i_blocks={}", identifier(), m_raw_inode.i_size, m_raw_inode.i_blocks);
if (Kernel::is_symlink(m_raw_inode.i_mode) && m_raw_inode.i_blocks == 0)
return {};
unsigned const block_size = fs().logical_block_size();
unsigned const entries_per_block = EXT2_ADDR_PER_BLOCK(&fs().super_block());
auto deallocate_block = [&](auto on_disk_block_index) -> ErrorOr<void> {
TRY(fs().set_block_allocation_state(on_disk_block_index, false));
m_raw_inode.i_blocks -= fs().i_blocks_increment();
return {};
};
auto process_block_array = [&](auto current_logical_index, unsigned level, auto array_block_index, ByteBuffer& array_storage, auto&& callback) -> ErrorOr<void> {
TRY(array_storage.try_resize(block_size));
auto* array = bit_cast<u32*>(array_storage.data());
auto buffer = UserOrKernelBuffer::for_kernel_buffer(bit_cast<u8*>(array));
TRY(fs().read_block(array_block_index, &buffer, block_size, 0));
for (unsigned i = 0; i < block_size / sizeof(u32); ++i) {
if (array[i] != 0)
TRY(callback(current_logical_index + i * AK::pow(entries_per_block, level - 1), array[i]));
}
return deallocate_block(array_block_index);
};
for (size_t i = 0; i < EXT2_NDIR_BLOCKS; ++i) {
if (m_raw_inode.i_block[i] != 0)
TRY(deallocate_block(m_raw_inode.i_block[i]));
}
ByteBuffer block_storage[3] = {};
if (m_raw_inode.i_block[EXT2_IND_BLOCK]) {
TRY(process_block_array(EXT2_NDIR_BLOCKS, 1, m_raw_inode.i_block[EXT2_IND_BLOCK], block_storage[0], [&]([[maybe_unused]] auto logical_block_index, auto on_disk_index) -> ErrorOr<void> {
return deallocate_block(on_disk_index);
}));
}
if (m_raw_inode.i_block[EXT2_DIND_BLOCK]) {
TRY(process_block_array(singly_indirect_block_capacity(), 2, m_raw_inode.i_block[EXT2_DIND_BLOCK], block_storage[1], [&](auto logical_block_index, auto on_disk_index) -> ErrorOr<void> {
return process_block_array(logical_block_index, 1, on_disk_index, block_storage[0], [&]([[maybe_unused]] auto logical_block_index2, auto on_disk_index2) -> ErrorOr<void> {
return deallocate_block(on_disk_index2);
});
}));
}
if (m_raw_inode.i_block[EXT2_TIND_BLOCK]) {
TRY(process_block_array(doubly_indirect_block_capacity(), 3, m_raw_inode.i_block[EXT2_TIND_BLOCK], block_storage[2], [&](auto logical_block_index, auto on_disk_index) -> ErrorOr<void> {
return process_block_array(logical_block_index, 2, on_disk_index, block_storage[1], [&](auto logical_block_index2, auto on_disk_index2) -> ErrorOr<void> {
return process_block_array(logical_block_index2, 1, on_disk_index2, block_storage[0], [&]([[maybe_unused]] auto logical_block_index3, auto on_disk_index3) -> ErrorOr<void> {
return deallocate_block(on_disk_index3);
});
});
}));
}
return {};
}
Ext2FSInode::Ext2FSInode(Ext2FS& fs, InodeIndex index)
: Inode(fs, index)
, m_block_view(*this)
{
}
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 = inode_uid(m_raw_inode);
metadata.gid = inode_gid(m_raw_inode);
metadata.link_count = m_raw_inode.i_links_count;
metadata.atime = UnixDateTime::from_seconds_since_epoch(m_raw_inode.i_atime);
metadata.ctime = UnixDateTime::from_seconds_since_epoch(m_raw_inode.i_ctime);
metadata.mtime = UnixDateTime::from_seconds_since_epoch(m_raw_inode.i_mtime);
metadata.dtime = UnixDateTime::from_seconds_since_epoch(m_raw_inode.i_dtime);
metadata.block_size = fs().logical_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);
if (!is_metadata_dirty())
return {};
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<size_t> Ext2FSInode::read_bytes_locked(off_t offset, size_t count, UserOrKernelBuffer& buffer, OpenFileDescription* description) const
{
VERIFY(m_inode_lock.is_locked());
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;
}
bool allow_cache = !description || !description->is_direct();
int const block_size = fs().logical_block_size();
BlockBasedFileSystem::BlockIndex first_block_logical_index = offset / block_size;
int offset_into_first_block = offset % block_size;
size_t nread = 0;
auto remaining_count = min((off_t)count, (off_t)size() - offset);
auto current_block_logical_index = first_block_logical_index;
dbgln_if(EXT2_VERY_DEBUG, "Ext2FSInode[{}]::read_bytes(): Reading up to {} bytes, {} bytes into inode to {}", identifier(), count, offset, buffer.user_or_kernel_ptr());
while (remaining_count) {
auto block_index = TRY(m_block_view.get_block(current_block_logical_index));
size_t offset_into_block = (current_block_logical_index == 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(), current_block_logical_index);
return result.release_error();
}
}
current_block_logical_index = current_block_logical_index.value() + 1;
remaining_count -= num_bytes_to_copy;
nread += num_bytes_to_copy;
}
return nread;
}
ErrorOr<void> Ext2FSInode::resize(u64 new_size)
{
VERIFY(m_inode_lock.is_locked());
if (size() == new_size)
return {};
if (!((u32)fs().get_features_readonly() & (u32)Ext2FS::FeaturesReadOnly::FileSize64bits) && (new_size >= static_cast<u32>(-1)))
return ENOSPC;
if (new_size < size()) {
auto block_size = fs().logical_block_size();
BlockBasedFileSystem::BlockIndex first_block_logical_index = ceil_div(new_size, block_size);
BlockBasedFileSystem::BlockIndex last_block_logical_index = size() / block_size;
for (auto bi = first_block_logical_index; bi <= last_block_logical_index; bi = bi.value() + 1) {
auto block = TRY(m_block_view.get_block(bi));
if (block == 0) {
// This is a hole, skip it.
continue;
}
if (auto result = fs().set_block_allocation_state(block, false); result.is_error()) {
dbgln("Ext2FSInode[{}]::resize(): Failed to free block {}: {}", identifier(), block, result.error());
return result;
}
m_raw_inode.i_blocks -= fs().i_blocks_increment();
TRY(m_block_view.write_block_pointer(bi, 0));
}
}
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);
return {};
}
ErrorOr<size_t> Ext2FSInode::write_bytes_locked(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_locked(): 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().logical_block_size();
auto new_size = max(static_cast<u64>(offset) + count, size());
TRY(resize(new_size));
BlockBasedFileSystem::BlockIndex first_block_logical_index = offset / block_size;
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);
auto current_block_logical_index = first_block_logical_index;
dbgln_if(EXT2_VERY_DEBUG, "Ext2FSInode[{}]::write_bytes_locked(): Writing {} bytes, {} bytes into inode from {}", identifier(), count, offset, data.user_or_kernel_ptr());
while (remaining_count) {
size_t offset_into_block = (current_block_logical_index == 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 block_index = TRY(m_block_view.get_or_allocate_block(current_block_logical_index, num_bytes_to_copy != block_size, allow_cache));
TRY(m_block_view.write_block_pointer(current_block_logical_index, block_index));
dbgln_if(EXT2_DEBUG, "Ext2FSInode[{}]::write_bytes_locked(): Writing block {} (offset_into_block: {})", identifier(), block_index, offset_into_block);
if (auto result = fs().write_block(block_index, data.offset(nwritten), num_bytes_to_copy, offset_into_block, allow_cache); result.is_error()) {
dbgln("Ext2FSInode[{}]::write_bytes_locked(): Failed to write block {} (index {})", identifier(), block_index, current_block_logical_index);
return result.release_error();
}
current_block_logical_index = current_block_logical_index.value() + 1;
remaining_count -= num_bytes_to_copy;
nwritten += num_bytes_to_copy;
}
did_modify_contents();
dbgln_if(EXT2_VERY_DEBUG, "Ext2FSInode[{}]::write_bytes_locked(): After write, i_size={}, i_blocks={}", identifier(), size(), m_raw_inode.i_blocks);
return nwritten;
}
ErrorOr<void> Ext2FSInode::traverse_as_directory(Function<ErrorOr<void>(FileSystem::DirectoryEntryView const&)> callback) const
{
MutexLocker locker(m_inode_lock);
VERIFY(is_directory());
u8 buffer[max_block_size];
auto buf = UserOrKernelBuffer::for_kernel_buffer(buffer);
auto block_size = fs().logical_block_size();
auto file_size = size();
bool has_file_type_attribute = has_flag(fs().get_features_optional(), Ext2FS::FeaturesOptional::ExtendedAttributes);
// 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));
using ext2_extended_dir_entry = ext2_dir_entry_2;
auto* entry = reinterpret_cast<ext2_extended_dir_entry*>(buffer);
auto* entries_end = reinterpret_cast<ext2_extended_dir_entry*>(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 }, has_file_type_attribute ? entry->file_type : (u8)EXT2_FT_UNKNOWN }));
}
entry = (ext2_extended_dir_entry*)((char*)entry + entry->rec_len);
}
}
return {};
}
ErrorOr<void> Ext2FSInode::write_directory(Vector<Ext2FSDirectoryEntry>& entries)
{
MutexLocker locker(m_inode_lock);
auto block_size = fs().logical_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));
FixedMemoryStream stream { directory_data.bytes() };
bool has_file_type_attribute = has_flag(fs().get_features_optional(), Ext2FS::FeaturesOptional::ExtendedAttributes);
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);
MUST(stream.write_value<u32>(entry.inode_index.value()));
MUST(stream.write_value<u16>(entry.record_length));
MUST(stream.write_value<u8>(entry.name->length()));
MUST(stream.write_value<u8>(has_file_type_attribute ? entry.file_type : EXT2_FT_UNKNOWN));
MUST(stream.write_until_depleted(entry.name->bytes()));
int padding = entry.record_length - entry.name->length() - 8;
for (int j = 0; j < padding; ++j)
MUST(stream.write_value<u8>(0));
}
auto serialized_bytes_count = TRY(stream.tell());
VERIFY(serialized_bytes_count == directory_size);
TRY(resize(serialized_bytes_count));
auto buffer = UserOrKernelBuffer::for_kernel_buffer(directory_data.data());
auto nwritten = TRY(prepare_and_write_bytes_locked(0, serialized_bytes_count, buffer, nullptr));
set_metadata_dirty(true);
if (nwritten != directory_data.size())
return EIO;
return {};
}
ErrorOr<BlockBasedFileSystem::BlockIndex> Ext2FSInode::allocate_block(BlockBasedFileSystem::BlockIndex block_index, bool zero_newly_allocated_block, bool allow_cache)
{
// FIXME: Preallocate some extra blocks here.
auto blocks = TRY(fs().allocate_blocks(fs().group_index_from_inode(index()), 1));
m_raw_inode.i_blocks += fs().i_blocks_increment();
VERIFY(blocks.size() == 1);
auto block = blocks.first();
if (zero_newly_allocated_block) {
u8 zero_buffer[PAGE_SIZE] {};
if (auto result = fs().write_block(block, UserOrKernelBuffer::for_kernel_buffer(zero_buffer), fs().logical_block_size(), 0, allow_cache); result.is_error()) {
dbgln("Ext2FSInode[{}]::allocate_block(): Failed to zero block {} (index {})", identifier(), block, block_index);
return result.release_error();
}
}
return block;
}
ErrorOr<NonnullRefPtr<Inode>> Ext2FSInode::create_child(StringView name, mode_t mode, dev_t dev, UserID uid, GroupID gid)
{
if (Kernel::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());
bool has_file_type_attribute = has_flag(fs().get_features_optional(), Ext2FS::FeaturesOptional::ExtendedAttributes);
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(), has_file_type_attribute ? entry.file_type : (u8)EXT2_FT_UNKNOWN }));
return {};
}));
TRY(child.increment_link_count());
auto entry_name = TRY(KString::try_create(name));
TRY(entries.try_empend(move(entry_name), child.index(), has_file_type_attribute ? to_ext2_file_type(mode) : (u8)EXT2_FT_UNKNOWN));
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 };
bool has_file_type_attribute = has_flag(fs().get_features_optional(), Ext2FS::FeaturesOptional::ExtendedAttributes);
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(), has_file_type_attribute ? entry.file_type : (u8)EXT2_FT_UNKNOWN }));
}
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 {};
}
ErrorOr<void> Ext2FSInode::replace_child(StringView name, Inode& child)
{
MutexLocker locker(m_inode_lock);
dbgln_if(EXT2_DEBUG, "Ext2FSInode[{}]::replace_child(): Replacing '{}' with inode {}", identifier(), name, child.index());
VERIFY(is_directory());
TRY(populate_lookup_cache());
if (name.length() > EXT2_NAME_LEN)
return ENAMETOOLONG;
Vector<Ext2FSDirectoryEntry> entries;
bool has_file_type_attribute = has_flag(fs().get_features_optional(), Ext2FS::FeaturesOptional::ExtendedAttributes);
Optional<InodeIndex> old_child_index;
TRY(traverse_as_directory([&](auto& entry) -> ErrorOr<void> {
auto is_replacing_this_inode = name == entry.name;
auto inode_index = is_replacing_this_inode ? child.index() : entry.inode.index();
auto entry_name = TRY(KString::try_create(entry.name));
TRY(entries.try_empend(move(entry_name), inode_index, has_file_type_attribute ? to_ext2_file_type(child.mode()) : (u8)EXT2_FT_UNKNOWN));
if (is_replacing_this_inode)
old_child_index = entry.inode.index();
return {};
}));
if (!old_child_index.has_value())
return ENOENT;
auto old_child = TRY(fs().get_inode({ fsid(), *old_child_index }));
auto old_index_it = m_lookup_cache.find(name);
VERIFY(old_index_it != m_lookup_cache.end());
old_index_it->value = child.index();
// NOTE: Between this line and the write_directory line, all operations must
// be atomic. Any changes made should be reverted.
TRY(child.increment_link_count());
auto maybe_decrement_error = old_child->decrement_link_count();
if (maybe_decrement_error.is_error()) {
old_index_it->value = *old_child_index;
MUST(child.decrement_link_count());
return maybe_decrement_error;
}
// FIXME: The filesystem is left in an inconsistent state if this fails.
// Revert the changes made above if we can't write_directory.
// Ideally, decrement should be the last operation, but we currently
// can't "un-write" a directory entry list.
TRY(write_directory(entries));
// TODO: Emit a did_replace_child event.
return {};
}
ErrorOr<void> Ext2FSInode::populate_lookup_cache()
{
VERIFY(m_inode_lock.is_exclusively_locked_by_current_thread());
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<NonnullRefPtr<Inode>> Ext2FSInode::lookup(StringView name)
{
VERIFY(is_directory());
dbgln_if(EXT2_DEBUG, "Ext2FSInode[{}]:lookup(): Looking up '{}'", identifier(), name);
InodeIndex inode_index;
{
MutexLocker locker(m_inode_lock);
TRY(populate_lookup_cache());
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<UnixDateTime> atime, Optional<UnixDateTime> ctime, Optional<UnixDateTime> mtime)
{
MutexLocker locker(m_inode_lock);
if (fs().is_readonly())
return EROFS;
if (atime.value_or({}).to_timespec().tv_sec > NumericLimits<i32>::max())
return EINVAL;
if (ctime.value_or({}).to_timespec().tv_sec > NumericLimits<i32>::max())
return EINVAL;
if (mtime.value_or({}).to_timespec().tv_sec > NumericLimits<i32>::max())
return EINVAL;
if (atime.has_value())
m_raw_inode.i_atime = atime.value().to_timespec().tv_sec;
if (ctime.has_value())
m_raw_inode.i_ctime = ctime.value().to_timespec().tv_sec;
if (mtime.has_value())
m_raw_inode.i_mtime = mtime.value().to_timespec().tv_sec;
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 {};
}
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 (inode_uid(m_raw_inode) == uid && inode_gid(m_raw_inode) == gid)
return {};
m_raw_inode.i_uid = static_cast<u16>(uid.value());
ext2fs_set_i_uid_high(m_raw_inode, uid.value() >> 16);
m_raw_inode.i_gid = static_cast<u16>(gid.value());
ext2fs_set_i_gid_high(m_raw_inode, gid.value() >> 16);
set_metadata_dirty(true);
return {};
}
ErrorOr<void> Ext2FSInode::truncate_locked(u64 size)
{
VERIFY(m_inode_lock.is_locked());
if (static_cast<u64>(m_raw_inode.i_size) == size)
return {};
TRY(resize(size));
set_metadata_dirty(true);
did_modify_contents();
return {};
}
ErrorOr<int> Ext2FSInode::get_block_address(int index)
{
MutexLocker locker(m_inode_lock);
if (index < 0)
return 0;
return TRY(m_block_view.get_block(index)).value();
}
}
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