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ladybird/Kernel/FileSystem/Ext2FileSystem.cpp
Mart G cab6155254 Kernel: Allow Ext2FSInode::write_bytes calls with a byte count of zero 
write_bytes is called with a count of 0 bytes if a directory is being
deleted, because in that case even the . and .. pseudo directories are
getting removed. In this case write_bytes is now a no-op.

Before write_bytes would fail because it would check to see if there
were any blocks available to write in (even though it wasn't going to
write in them anyway).

This behaviour was uncovered because of a recent change where
directories are correctly reduced in size. Which in this case results in
all the blocks being removed from the inode, whereas previously there
would be some stale blocks around to pass the check.
2021-05-07 21:11:55 +02:00

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/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/HashMap.h>
#include <AK/MemoryStream.h>
#include <AK/StdLibExtras.h>
#include <AK/StringView.h>
#include <Kernel/Debug.h>
#include <Kernel/Devices/BlockDevice.h>
#include <Kernel/FileSystem/Ext2FileSystem.h>
#include <Kernel/FileSystem/FileDescription.h>
#include <Kernel/FileSystem/ext2_fs.h>
#include <Kernel/Process.h>
#include <Kernel/UnixTypes.h>
#include <LibC/errno_numbers.h>
namespace Kernel {
static const size_t max_link_count = 65535;
static const size_t max_block_size = 4096;
static const ssize_t max_inline_symlink_length = 60;
struct Ext2FSDirectoryEntry {
String name;
InodeIndex inode_index { 0 };
u8 file_type { 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;
}
static unsigned divide_rounded_up(unsigned a, unsigned b)
{
return (a / b) + (a % b != 0);
}
NonnullRefPtr<Ext2FS> Ext2FS::create(FileDescription& file_description)
{
return adopt_ref(*new Ext2FS(file_description));
}
Ext2FS::Ext2FS(FileDescription& file_description)
: BlockBasedFS(file_description)
{
}
Ext2FS::~Ext2FS()
{
}
bool Ext2FS::flush_super_block()
{
Locker locker(m_lock);
VERIFY((sizeof(ext2_super_block) % logical_block_size()) == 0);
auto super_block_buffer = UserOrKernelBuffer::for_kernel_buffer((u8*)&m_super_block);
bool success = raw_write_blocks(2, (sizeof(ext2_super_block) / logical_block_size()), super_block_buffer);
VERIFY(success);
return true;
}
const ext2_group_desc& 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];
}
bool Ext2FS::initialize()
{
Locker locker(m_lock);
VERIFY((sizeof(ext2_super_block) % logical_block_size()) == 0);
auto super_block_buffer = UserOrKernelBuffer::for_kernel_buffer((u8*)&m_super_block);
bool success = raw_read_blocks(2, (sizeof(ext2_super_block) / logical_block_size()), super_block_buffer);
VERIFY(success);
auto& 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)
return false;
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));
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 false;
}
unsigned 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 = KBuffer::try_create_with_size(block_size() * blocks_to_read, Region::Access::Read | Region::Access::Write, "Ext2FS: Block group descriptors");
if (!m_cached_group_descriptor_table) {
dbgln("Ext2FS: Failed to allocate memory for group descriptor table");
return false;
}
auto buffer = UserOrKernelBuffer::for_kernel_buffer(m_cached_group_descriptor_table->data());
if (auto result = read_blocks(first_block_of_bgdt, blocks_to_read, buffer); result.is_error()) {
// FIXME: Propagate the error
dbgln("Ext2FS: initialize had error: {}", result.error());
return false;
}
if constexpr (EXT2_DEBUG) {
for (unsigned i = 1; i <= m_block_group_count; ++i) {
auto& 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);
}
}
return true;
}
const char* Ext2FS::class_name() const
{
return "Ext2FS";
}
NonnullRefPtr<Inode> Ext2FS::root_inode() const
{
return *get_inode({ fsid(), EXT2_ROOT_INO });
}
bool Ext2FS::find_block_containing_inode(InodeIndex inode, BlockIndex& block_index, unsigned& offset) const
{
auto& 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& bgd = group_descriptor(group_index_from_inode(inode));
offset = ((inode.value() - 1) % inodes_per_group()) * inode_size();
block_index = bgd.bg_inode_table + (offset >> EXT2_BLOCK_SIZE_BITS(&super_block));
offset &= block_size() - 1;
return true;
}
Ext2FS::BlockListShape Ext2FS::compute_block_list_shape(unsigned blocks) const
{
BlockListShape shape;
const unsigned 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 += divide_rounded_up(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 += divide_rounded_up(shape.triply_indirect_blocks, entries_per_block * entries_per_block);
shape.meta_blocks += divide_rounded_up(shape.triply_indirect_blocks, entries_per_block);
blocks_remaining -= shape.triply_indirect_blocks;
VERIFY(blocks_remaining == 0);
return shape;
}
KResult Ext2FSInode::write_indirect_block(BlockBasedFS::BlockIndex block, Span<BlockBasedFS::BlockIndex> blocks_indices)
{
const auto entries_per_block = EXT2_ADDR_PER_BLOCK(&fs().super_block());
VERIFY(blocks_indices.size() <= entries_per_block);
auto block_contents = 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());
}
KResult Ext2FSInode::grow_doubly_indirect_block(BlockBasedFS::BlockIndex block, size_t old_blocks_length, Span<BlockBasedFS::BlockIndex> blocks_indices, Vector<Ext2FS::BlockIndex>& new_meta_blocks, unsigned& meta_blocks)
{
const auto entries_per_block = EXT2_ADDR_PER_BLOCK(&fs().super_block());
const auto entries_per_doubly_indirect_block = entries_per_block * entries_per_block;
const auto old_indirect_blocks_length = divide_rounded_up(old_blocks_length, entries_per_block);
const auto new_indirect_blocks_length = divide_rounded_up(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 = 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) {
if (auto result = fs().read_block(block, &buffer, fs().block_size()); result.is_error())
return result;
}
// 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++) {
const auto offset_block = i * entries_per_block;
if (auto result = write_indirect_block(block_as_pointers[i], blocks_indices.slice(offset_block, min(blocks_indices.size() - offset_block, entries_per_block))); result.is_error())
return result;
}
// Write out the doubly indirect block.
return fs().write_block(block, buffer, stream.size());
}
KResult Ext2FSInode::shrink_doubly_indirect_block(BlockBasedFS::BlockIndex block, size_t old_blocks_length, size_t new_blocks_length, unsigned& meta_blocks)
{
const auto entries_per_block = EXT2_ADDR_PER_BLOCK(&fs().super_block());
const auto entries_per_doubly_indirect_block = entries_per_block * entries_per_block;
const auto old_indirect_blocks_length = divide_rounded_up(old_blocks_length, entries_per_block);
const auto new_indirect_blocks_length = divide_rounded_up(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 = 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));
if (auto result = fs().read_block(block, &buffer, fs().block_size()); result.is_error())
return result;
// 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);
if (auto result = fs().set_block_allocation_state(block_as_pointers[i], false); result.is_error())
return result;
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);
if (auto result = fs().set_block_allocation_state(block, false); result.is_error())
return result;
meta_blocks--;
}
return KSuccess;
}
KResult Ext2FSInode::grow_triply_indirect_block(BlockBasedFS::BlockIndex block, size_t old_blocks_length, Span<BlockBasedFS::BlockIndex> blocks_indices, Vector<Ext2FS::BlockIndex>& new_meta_blocks, unsigned& meta_blocks)
{
const auto entries_per_block = EXT2_ADDR_PER_BLOCK(&fs().super_block());
const auto entries_per_doubly_indirect_block = entries_per_block * entries_per_block;
const auto entries_per_triply_indirect_block = entries_per_block * entries_per_block;
const auto old_doubly_indirect_blocks_length = divide_rounded_up(old_blocks_length, entries_per_doubly_indirect_block);
const auto new_doubly_indirect_blocks_length = divide_rounded_up(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 = 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) {
if (auto result = fs().read_block(block, &buffer, fs().block_size()); result.is_error())
return result;
}
// 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++) {
const auto processed_blocks = i * entries_per_doubly_indirect_block;
const auto old_doubly_indirect_blocks_length = min(old_blocks_length > processed_blocks ? old_blocks_length - processed_blocks : 0, entries_per_doubly_indirect_block);
const auto new_doubly_indirect_blocks_length = min(blocks_indices.size() > processed_blocks ? blocks_indices.size() - processed_blocks : 0, entries_per_doubly_indirect_block);
if (auto result = 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); result.is_error())
return result;
}
// Write out the triply indirect block.
return fs().write_block(block, buffer, stream.size());
}
KResult Ext2FSInode::shrink_triply_indirect_block(BlockBasedFS::BlockIndex block, size_t old_blocks_length, size_t new_blocks_length, unsigned& meta_blocks)
{
const auto entries_per_block = EXT2_ADDR_PER_BLOCK(&fs().super_block());
const auto entries_per_doubly_indirect_block = entries_per_block * entries_per_block;
const auto entries_per_triply_indirect_block = entries_per_doubly_indirect_block * entries_per_block;
const auto old_triply_indirect_blocks_length = divide_rounded_up(old_blocks_length, entries_per_doubly_indirect_block);
const auto 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 = 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));
if (auto result = fs().read_block(block, &buffer, fs().block_size()); result.is_error())
return result;
// Shrink the doubly indirect blocks.
for (unsigned i = new_triply_indirect_blocks_length; i < old_triply_indirect_blocks_length; i++) {
const auto processed_blocks = i * entries_per_doubly_indirect_block;
const auto old_doubly_indirect_blocks_length = min(old_blocks_length > processed_blocks ? old_blocks_length - processed_blocks : 0, entries_per_doubly_indirect_block);
const auto 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);
if (auto result = shrink_doubly_indirect_block(block_as_pointers[i], old_doubly_indirect_blocks_length, new_doubly_indirect_blocks_length, meta_blocks); result.is_error())
return result;
}
// 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);
if (auto result = fs().set_block_allocation_state(block, false); result.is_error())
return result;
meta_blocks--;
}
return KSuccess;
}
KResult Ext2FSInode::flush_block_list()
{
Locker locker(m_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 KSuccess;
}
// NOTE: There is a mismatch between i_blocks and blocks.size() since i_blocks includes meta blocks and blocks.size() does not.
const auto old_block_count = ceil_div(size(), static_cast<u64>(fs().block_size()));
auto old_shape = fs().compute_block_list_shape(old_block_count);
const auto 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) {
auto blocks_or_error = fs().allocate_blocks(fs().group_index_from_inode(index()), new_shape.meta_blocks - old_shape.meta_blocks);
if (blocks_or_error.is_error())
return blocks_or_error.error();
new_meta_blocks = blocks_or_error.release_value();
}
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 (BlockBasedFS::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++;
}
if (auto result = write_indirect_block(m_raw_inode.i_block[EXT2_IND_BLOCK], m_block_list.span().slice(output_block_index, new_shape.indirect_blocks)); result.is_error())
return result;
} 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]);
if (auto result = fs().set_block_allocation_state(m_raw_inode.i_block[EXT2_IND_BLOCK], false); result.is_error())
return result;
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++;
}
if (auto result = 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); result.is_error())
return result;
} else {
if (auto result = 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); result.is_error())
return result;
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++;
}
if (auto result = 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); result.is_error())
return result;
} else {
if (auto result = 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); result.is_error())
return result;
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 KSuccess;
dbgln("we don't know how to write qind ext2fs blocks, they don't exist anyway!");
VERIFY_NOT_REACHED();
}
Vector<Ext2FS::BlockIndex> Ext2FSInode::compute_block_list() const
{
return compute_block_list_impl(false);
}
Vector<Ext2FS::BlockIndex> Ext2FSInode::compute_block_list_with_meta_blocks() const
{
return compute_block_list_impl(true);
}
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 = 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;
}
Vector<Ext2FS::BlockIndex> Ext2FSInode::compute_block_list_impl_internal(const ext2_inode& 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) {
if (blocks_remaining) {
list.append(bi);
--blocks_remaining;
}
};
if (include_block_list_blocks) {
// This seems like an excessive over-estimate but w/e.
list.ensure_capacity(blocks_remaining * 2);
} else {
list.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];
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) {
if (include_block_list_blocks)
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 = ByteBuffer::create_uninitialized(read_size);
auto* array = (u32*)array_storage.data();
auto buffer = UserOrKernelBuffer::for_kernel_buffer((u8*)array);
if (auto result = fs().read_block(array_block_index, &buffer, read_size, 0); result.is_error()) {
// FIXME: Stop here and propagate this error.
dbgln("Ext2FSInode[{}]::compute_block_list_impl_internal(): Error: {}", identifier(), result.error());
}
for (unsigned i = 0; i < count; ++i)
callback(Ext2FS::BlockIndex(array[i]));
};
process_block_array(e2inode.i_block[EXT2_IND_BLOCK], [&](auto block_index) {
add_block(block_index);
});
if (!blocks_remaining)
return list;
process_block_array(e2inode.i_block[EXT2_DIND_BLOCK], [&](auto block_index) {
process_block_array(block_index, [&](auto block_index2) {
add_block(block_index2);
});
});
if (!blocks_remaining)
return list;
process_block_array(e2inode.i_block[EXT2_TIND_BLOCK], [&](auto block_index) {
process_block_array(block_index, [&](auto block_index2) {
process_block_array(block_index2, [&](auto block_index3) {
add_block(block_index3);
});
});
});
return list;
}
void Ext2FS::free_inode(Ext2FSInode& inode)
{
Locker 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.
for (auto block_index : inode.compute_block_list_with_meta_blocks()) {
VERIFY(block_index <= super_block().s_blocks_count);
if (block_index.value()) {
if (auto result = set_block_allocation_state(block_index, false); result.is_error()) {
dbgln("Ext2FS[{}]::free_inode(): Failed to deallocate block {} for inode {}", fsid(), block_index, inode.index());
}
}
}
// 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();
write_ext2_inode(inode.index(), inode.m_raw_inode);
// Mark the inode as free.
if (auto result = set_inode_allocation_state(inode.index(), false); result.is_error())
dbgln("Ext2FS[{}]::free_inode(): Failed to free inode {}: {}", fsid(), inode.index(), result.error());
}
void Ext2FS::flush_block_group_descriptor_table()
{
Locker locker(m_lock);
unsigned blocks_to_write = ceil_div(m_block_group_count * sizeof(ext2_group_desc), block_size());
unsigned 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()
{
Locker locker(m_lock);
if (m_super_block_dirty) {
flush_super_block();
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);
}
}
BlockBasedFS::flush_writes();
// 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.
Vector<InodeIndex> unused_inodes;
for (auto& it : m_inode_cache) {
if (it.value->ref_count() != 1)
continue;
if (it.value->has_watchers())
continue;
unused_inodes.append(it.key);
}
for (auto index : unused_inodes)
uncache_inode(index);
}
Ext2FSInode::Ext2FSInode(Ext2FS& fs, InodeIndex index)
: Inode(fs, index)
{
}
Ext2FSInode::~Ext2FSInode()
{
if (m_raw_inode.i_links_count == 0)
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
{
Locker locker(m_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;
}
void Ext2FSInode::flush_metadata()
{
Locker locker(m_lock);
dbgln_if(EXT2_DEBUG, "Ext2FSInode[{}]::flush_metadata(): Flushing inode", identifier());
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);
}
RefPtr<Inode> Ext2FS::get_inode(InodeIdentifier inode) const
{
Locker locker(m_lock);
VERIFY(inode.fsid() == fsid());
{
auto it = m_inode_cache.find(inode.index());
if (it != m_inode_cache.end())
return (*it).value;
}
auto state_or_error = get_inode_allocation_state(inode.index());
if (state_or_error.is_error())
return {};
if (!state_or_error.value()) {
m_inode_cache.set(inode.index(), nullptr);
return {};
}
BlockIndex block_index;
unsigned offset;
if (!find_block_containing_inode(inode.index(), block_index, offset))
return {};
auto new_inode = adopt_ref(*new Ext2FSInode(const_cast<Ext2FS&>(*this), inode.index()));
auto buffer = UserOrKernelBuffer::for_kernel_buffer(reinterpret_cast<u8*>(&new_inode->m_raw_inode));
if (auto result = read_block(block_index, &buffer, sizeof(ext2_inode), offset); result.is_error()) {
// FIXME: Propagate the actual error.
return nullptr;
}
m_inode_cache.set(inode.index(), new_inode);
return new_inode;
}
KResultOr<ssize_t> Ext2FSInode::read_bytes(off_t offset, ssize_t count, UserOrKernelBuffer& buffer, FileDescription* description) const
{
Locker inode_locker(m_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);
ssize_t nread = min((off_t)size() - offset, static_cast<off_t>(count));
if (!buffer.write(((const u8*)m_raw_inode.i_block) + offset, (size_t)nread))
return EFAULT;
return nread;
}
if (m_block_list.is_empty())
m_block_list = 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();
const int block_size = fs().block_size();
BlockBasedFS::BlockIndex first_block_logical_index = offset / block_size;
BlockBasedFS::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;
ssize_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.
if (!buffer_offset.memset(0, num_bytes_to_copy))
return EFAULT;
} 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.error();
}
}
remaining_count -= num_bytes_to_copy;
nread += num_bytes_to_copy;
}
return nread;
}
KResult Ext2FSInode::resize(u64 new_size)
{
auto old_size = size();
if (old_size == new_size)
return KSuccess;
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 = this->compute_block_list();
if (blocks_needed_after > blocks_needed_before) {
auto blocks_or_error = fs().allocate_blocks(fs().group_index_from_inode(index()), blocks_needed_after - blocks_needed_before);
if (blocks_or_error.is_error())
return blocks_or_error.error();
if (!m_block_list.try_append(blocks_or_error.release_value()))
return ENOMEM;
} 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;
}
}
}
}
if (auto result = flush_block_list(); result.is_error())
return result;
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 result = write_bytes(clear_from, min(static_cast<u64>(sizeof(zero_buffer)), bytes_to_clear), UserOrKernelBuffer::for_kernel_buffer(zero_buffer), nullptr);
if (result.is_error())
return result.error();
VERIFY(result.value() != 0);
bytes_to_clear -= result.value();
clear_from += result.value();
}
}
return KSuccess;
}
KResultOr<ssize_t> Ext2FSInode::write_bytes(off_t offset, ssize_t count, const UserOrKernelBuffer& data, FileDescription* description)
{
VERIFY(offset >= 0);
VERIFY(count >= 0);
if (count == 0)
return 0;
Locker inode_locker(m_lock);
if (auto result = prepare_to_write_data(); result.is_error())
return result;
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(), data.copy_into_string(count), count);
if (!data.read(((u8*)m_raw_inode.i_block) + offset, (size_t)count))
return EFAULT;
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();
const auto block_size = fs().block_size();
auto new_size = max(static_cast<u64>(offset) + count, size());
if (auto result = resize(new_size); result.is_error())
return result;
if (m_block_list.is_empty())
m_block_list = compute_block_list();
if (m_block_list.is_empty()) {
dbgln("Ext2FSInode[{}]::write_bytes(): Empty block list", identifier());
return EIO;
}
BlockBasedFS::BlockIndex first_block_logical_index = offset / block_size;
BlockBasedFS::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;
ssize_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;
}
remaining_count -= num_bytes_to_copy;
nwritten += num_bytes_to_copy;
}
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(const DirectoryEntryView& 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;
}
KResult Ext2FSInode::traverse_as_directory(Function<bool(const FS::DirectoryEntryView&)> callback) const
{
Locker locker(m_lock);
VERIFY(is_directory());
auto buffer_or = read_entire();
if (buffer_or.is_error())
return buffer_or.error();
auto& buffer = *buffer_or.value();
auto* entry = reinterpret_cast<ext2_dir_entry_2*>(buffer.data());
while (entry < buffer.end_pointer()) {
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));
if (!callback({ { entry->name, entry->name_len }, { fsid(), entry->inode }, entry->file_type }))
break;
}
entry = (ext2_dir_entry_2*)((char*)entry + entry->rec_len);
}
return KSuccess;
}
KResult Ext2FSInode::write_directory(const Vector<Ext2FSDirectoryEntry>& entries)
{
Locker locker(m_lock);
int directory_size = 0;
for (auto& entry : entries)
directory_size += EXT2_DIR_REC_LEN(entry.name.length());
auto block_size = fs().block_size();
int blocks_needed = ceil_div(static_cast<size_t>(directory_size), block_size);
int occupied_size = blocks_needed * block_size;
dbgln_if(EXT2_DEBUG, "Ext2FSInode[{}]::write_directory(): New directory contents to write (size {}, occupied {}):", identifier(), directory_size, occupied_size);
auto directory_data = ByteBuffer::create_uninitialized(occupied_size);
OutputMemoryStream stream { directory_data };
for (size_t i = 0; i < entries.size(); ++i) {
auto& entry = entries[i];
int record_length = EXT2_DIR_REC_LEN(entry.name.length());
if (i == entries.size() - 1)
record_length += occupied_size - directory_size;
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(record_length), u8(entry.file_type), entry.name);
stream << u32(entry.inode_index.value());
stream << u16(record_length);
stream << u8(entry.name.length());
stream << u8(entry.file_type);
stream << entry.name.bytes();
int padding = record_length - entry.name.length() - 8;
for (int j = 0; j < padding; ++j)
stream << u8(0);
}
stream.fill_to_end(0);
if (auto result = resize(stream.size()); result.is_error())
return result;
auto buffer = UserOrKernelBuffer::for_kernel_buffer(stream.data());
auto result = write_bytes(0, stream.size(), buffer, nullptr);
if (result.is_error())
return result.error();
set_metadata_dirty(true);
if (static_cast<size_t>(result.value()) != directory_data.size())
return EIO;
return KSuccess;
}
KResultOr<NonnullRefPtr<Inode>> Ext2FSInode::create_child(const String& name, mode_t mode, dev_t dev, uid_t uid, gid_t gid)
{
if (::is_directory(mode))
return fs().create_directory(*this, name, mode, uid, gid);
return fs().create_inode(*this, name, mode, dev, uid, gid);
}
KResult Ext2FSInode::add_child(Inode& child, const StringView& name, mode_t mode)
{
Locker locker(m_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;
bool name_already_exists = false;
KResult result = traverse_as_directory([&](auto& entry) {
if (name == entry.name) {
name_already_exists = true;
return false;
}
entries.append({ entry.name, entry.inode.index(), entry.file_type });
return true;
});
if (result.is_error())
return result;
if (name_already_exists) {
dbgln("Ext2FSInode[{}]::add_child(): Name '{}' already exists", identifier(), name);
return EEXIST;
}
result = child.increment_link_count();
if (result.is_error())
return result;
entries.empend(name, child.index(), to_ext2_file_type(mode));
result = write_directory(entries);
if (result.is_error())
return result;
m_lookup_cache.set(name, child.index());
did_add_child(child.identifier());
return KSuccess;
}
KResult Ext2FSInode::remove_child(const StringView& name)
{
Locker locker(m_lock);
dbgln_if(EXT2_DEBUG, "Ext2FSInode[{}]::remove_child(): Removing '{}'", identifier(), name);
VERIFY(is_directory());
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;
KResult result = traverse_as_directory([&](auto& entry) {
if (name != entry.name)
entries.append({ entry.name, entry.inode.index(), entry.file_type });
return true;
});
if (result.is_error())
return result;
result = write_directory(entries);
if (result.is_error())
return result;
m_lookup_cache.remove(name);
auto child_inode = fs().get_inode(child_id);
result = child_inode->decrement_link_count();
if (result.is_error())
return result;
did_remove_child(child_id);
return KSuccess;
}
unsigned Ext2FS::inodes_per_block() const
{
return EXT2_INODES_PER_BLOCK(&super_block());
}
unsigned Ext2FS::inodes_per_group() const
{
return EXT2_INODES_PER_GROUP(&super_block());
}
unsigned Ext2FS::inode_size() const
{
return EXT2_INODE_SIZE(&super_block());
}
unsigned Ext2FS::blocks_per_group() const
{
return EXT2_BLOCKS_PER_GROUP(&super_block());
}
bool Ext2FS::write_ext2_inode(InodeIndex inode, const ext2_inode& e2inode)
{
BlockIndex block_index;
unsigned offset;
if (!find_block_containing_inode(inode, block_index, offset))
return false;
auto buffer = UserOrKernelBuffer::for_kernel_buffer(const_cast<u8*>((const u8*)&e2inode));
return write_block(block_index, buffer, inode_size(), offset) >= 0;
}
auto Ext2FS::allocate_blocks(GroupIndex preferred_group_index, size_t count) -> KResultOr<Vector<BlockIndex>>
{
Locker locker(m_lock);
dbgln_if(EXT2_DEBUG, "Ext2FS: allocate_blocks(preferred group: {}, count {})", preferred_group_index, count);
if (count == 0)
return Vector<BlockIndex> {};
Vector<BlockIndex> blocks;
dbgln_if(EXT2_DEBUG, "Ext2FS: allocate_blocks:");
blocks.ensure_capacity(count);
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& bgd = group_descriptor(group_index);
auto cached_bitmap_or_error = get_bitmap_block(bgd.bg_block_bitmap);
if (cached_bitmap_or_error.is_error())
return cached_bitmap_or_error.error();
auto& cached_bitmap = *cached_bitmap_or_error.value();
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();
if (auto result = set_block_allocation_state(block_index, true); result.is_error()) {
dbgln("Ext2FS: Failed to allocate block {} in allocate_blocks()", block_index);
return result;
}
blocks.unchecked_append(block_index);
dbgln_if(EXT2_DEBUG, " allocated > {}", block_index);
}
}
VERIFY(blocks.size() == count);
return blocks;
}
KResultOr<InodeIndex> Ext2FS::allocate_inode(GroupIndex preferred_group)
{
dbgln_if(EXT2_DEBUG, "Ext2FS: allocate_inode(preferred_group: {})", preferred_group);
Locker 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& 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_or_error = get_bitmap_block(bgd.bg_inode_bitmap);
if (cached_bitmap_or_error.is_error())
return cached_bitmap_or_error.error();
auto& cached_bitmap = *cached_bitmap_or_error.value();
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;
}
KResultOr<bool> Ext2FS::get_inode_allocation_state(InodeIndex index) const
{
Locker locker(m_lock);
if (index == 0)
return EINVAL;
auto group_index = group_index_from_inode(index);
auto& 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_or_error = const_cast<Ext2FS&>(*this).get_bitmap_block(bgd.bg_inode_bitmap);
if (cached_bitmap_or_error.is_error())
return cached_bitmap_or_error.error();
return cached_bitmap_or_error.value()->bitmap(inodes_per_group()).get(bit_index);
}
KResult 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_or_error = get_bitmap_block(bitmap_block);
if (cached_bitmap_or_error.is_error())
return cached_bitmap_or_error.error();
auto& cached_bitmap = *cached_bitmap_or_error.value();
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 KSuccess;
}
KResult Ext2FS::set_inode_allocation_state(InodeIndex inode_index, bool new_state)
{
Locker 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;
}
KResultOr<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;
}
auto block = KBuffer::create_with_size(block_size(), Region::Access::Read | Region::Access::Write, "Ext2FS: Cached bitmap block");
auto buffer = UserOrKernelBuffer::for_kernel_buffer(block.data());
if (auto result = read_block(bitmap_block_index, &buffer, block_size()); result.is_error()) {
dbgln("Ext2FS: Failed to load bitmap block {}", bitmap_block_index);
return result;
}
if (!m_cached_bitmaps.try_append(make<CachedBitmap>(bitmap_block_index, move(block))))
return ENOMEM;
return m_cached_bitmaps.last();
}
KResult Ext2FS::set_block_allocation_state(BlockIndex block_index, bool new_state)
{
VERIFY(block_index != 0);
Locker 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);
}
KResult Ext2FS::create_directory(Ext2FSInode& parent_inode, const String& name, mode_t mode, uid_t uid, gid_t gid)
{
Locker locker(m_lock);
VERIFY(is_directory(mode));
auto inode_or_error = create_inode(parent_inode, name, mode, 0, uid, gid);
if (inode_or_error.is_error())
return inode_or_error.error();
auto& inode = inode_or_error.value();
dbgln_if(EXT2_DEBUG, "Ext2FS: create_directory: created new directory named '{} with inode {}", name, inode->index());
Vector<Ext2FSDirectoryEntry> entries;
entries.empend(".", inode->index(), static_cast<u8>(EXT2_FT_DIR));
entries.empend("..", parent_inode.index(), static_cast<u8>(EXT2_FT_DIR));
if (auto result = static_cast<Ext2FSInode&>(*inode).write_directory(entries); result.is_error())
return result;
if (auto result = parent_inode.increment_link_count(); result.is_error())
return result;
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 KSuccess;
}
KResultOr<NonnullRefPtr<Inode>> Ext2FS::create_inode(Ext2FSInode& parent_inode, const String& name, mode_t mode, dev_t dev, uid_t uid, gid_t 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;
e2inode.i_gid = gid;
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 = allocate_inode();
if (inode_id.is_error())
return inode_id.error();
dbgln_if(EXT2_DEBUG, "Ext2FS: writing initial metadata for inode {}", inode_id.value());
auto success = write_ext2_inode(inode_id.value(), e2inode);
VERIFY(success);
auto new_inode = get_inode({ fsid(), inode_id.value() });
VERIFY(new_inode);
dbgln_if(EXT2_DEBUG, "Ext2FS: Adding inode '{}' (mode {:o}) to parent directory {}", name, mode, parent_inode.index());
if (auto result = parent_inode.add_child(*new_inode, name, mode); result.is_error())
return result;
return new_inode.release_nonnull();
}
bool Ext2FSInode::populate_lookup_cache() const
{
Locker locker(m_lock);
if (!m_lookup_cache.is_empty())
return true;
HashMap<String, InodeIndex> children;
KResult result = traverse_as_directory([&children](auto& entry) {
children.set(entry.name, entry.inode.index());
return true;
});
if (!result.is_success())
return false;
if (!m_lookup_cache.is_empty())
return false;
m_lookup_cache = move(children);
return true;
}
RefPtr<Inode> Ext2FSInode::lookup(StringView name)
{
VERIFY(is_directory());
dbgln_if(EXT2_DEBUG, "Ext2FSInode[{}]:lookup(): Looking up '{}'", identifier(), name);
if (!populate_lookup_cache())
return {};
Locker locker(m_lock);
auto it = m_lookup_cache.find(name.hash(), [&](auto& entry) { return entry.key == name; });
if (it != m_lookup_cache.end())
return fs().get_inode({ fsid(), (*it).value });
dbgln_if(EXT2_DEBUG, "Ext2FSInode[{}]:lookup(): '{}' not found", identifier(), name);
return {};
}
void Ext2FSInode::one_ref_left()
{
// FIXME: I would like to not live forever, but uncached Ext2FS is fucking painful right now.
}
KResult Ext2FSInode::set_atime(time_t t)
{
Locker locker(m_lock);
if (fs().is_readonly())
return EROFS;
m_raw_inode.i_atime = t;
set_metadata_dirty(true);
return KSuccess;
}
KResult Ext2FSInode::set_ctime(time_t t)
{
Locker locker(m_lock);
if (fs().is_readonly())
return EROFS;
m_raw_inode.i_ctime = t;
set_metadata_dirty(true);
return KSuccess;
}
KResult Ext2FSInode::set_mtime(time_t t)
{
Locker locker(m_lock);
if (fs().is_readonly())
return EROFS;
m_raw_inode.i_mtime = t;
set_metadata_dirty(true);
return KSuccess;
}
KResult Ext2FSInode::increment_link_count()
{
Locker locker(m_lock);
if (fs().is_readonly())
return EROFS;
if (m_raw_inode.i_links_count == max_link_count)
return EMLINK;
++m_raw_inode.i_links_count;
set_metadata_dirty(true);
return KSuccess;
}
KResult Ext2FSInode::decrement_link_count()
{
Locker locker(m_lock);
if (fs().is_readonly())
return EROFS;
VERIFY(m_raw_inode.i_links_count);
--m_raw_inode.i_links_count;
if (ref_count() == 1 && m_raw_inode.i_links_count == 0)
fs().uncache_inode(index());
set_metadata_dirty(true);
return KSuccess;
}
void Ext2FS::uncache_inode(InodeIndex index)
{
Locker locker(m_lock);
m_inode_cache.remove(index);
}
KResultOr<size_t> Ext2FSInode::directory_entry_count() const
{
VERIFY(is_directory());
Locker locker(m_lock);
populate_lookup_cache();
return m_lookup_cache.size();
}
KResult Ext2FSInode::chmod(mode_t mode)
{
Locker locker(m_lock);
if (m_raw_inode.i_mode == mode)
return KSuccess;
m_raw_inode.i_mode = mode;
set_metadata_dirty(true);
return KSuccess;
}
KResult Ext2FSInode::chown(uid_t uid, gid_t gid)
{
Locker locker(m_lock);
if (m_raw_inode.i_uid == uid && m_raw_inode.i_gid == gid)
return KSuccess;
m_raw_inode.i_uid = uid;
m_raw_inode.i_gid = gid;
set_metadata_dirty(true);
return KSuccess;
}
KResult Ext2FSInode::truncate(u64 size)
{
Locker locker(m_lock);
if (static_cast<u64>(m_raw_inode.i_size) == size)
return KSuccess;
if (auto result = resize(size); result.is_error())
return result;
set_metadata_dirty(true);
return KSuccess;
}
KResultOr<int> Ext2FSInode::get_block_address(int index)
{
Locker locker(m_lock);
if (m_block_list.is_empty())
m_block_list = 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
{
Locker locker(m_lock);
return super_block().s_blocks_count;
}
unsigned Ext2FS::free_block_count() const
{
Locker locker(m_lock);
return super_block().s_free_blocks_count;
}
unsigned Ext2FS::total_inode_count() const
{
Locker locker(m_lock);
return super_block().s_inodes_count;
}
unsigned Ext2FS::free_inode_count() const
{
Locker locker(m_lock);
return super_block().s_free_inodes_count;
}
KResult Ext2FS::prepare_to_unmount() const
{
Locker locker(m_lock);
for (auto& it : m_inode_cache) {
if (it.value->ref_count() > 1)
return EBUSY;
}
m_inode_cache.clear();
return KSuccess;
}
}
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