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ladybird/Kernel/FileSystem/Ext2FileSystem.cpp
Andreas Kling 9e4dd834ab Ext2FS: Simplify inode creation by always starting empty 
We had two ways of creating a new Ext2FS inode. Either they were empty,
or they started with some pre-allocated size.

In practice, the pre-sizing code path was only used for new directories
and it didn't actually improve anything as far as I can tell.

This patch simplifies inode creation by simply always allocating empty
inodes. Block allocation and block list generation now always happens
on the same code path.
2021-02-02 18:58:26 +01:00

1723 lines
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/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <AK/Bitmap.h>
#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;
InodeIdentifier inode;
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;
}
NonnullRefPtr<Ext2FS> Ext2FS::create(FileDescription& file_description)
{
return adopt(*new Ext2FS(file_description));
}
Ext2FS::Ext2FS(FileDescription& file_description)
: BlockBasedFS(file_description)
{
}
Ext2FS::~Ext2FS()
{
}
bool Ext2FS::flush_super_block()
{
LOCKER(m_lock);
ASSERT((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);
ASSERT(success);
return true;
}
const ext2_group_desc& Ext2FS::group_descriptor(GroupIndex group_index) const
{
// FIXME: Should this fail gracefully somehow?
ASSERT(group_index <= m_block_group_count);
return block_group_descriptors()[group_index - 1];
}
bool Ext2FS::initialize()
{
LOCKER(m_lock);
ASSERT((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);
ASSERT(success);
auto& super_block = this->super_block();
#if EXT2_DEBUG
klog() << "ext2fs: super block magic: " << String::format("%x", super_block.s_magic) << " (super block size: " << sizeof(ext2_super_block) << ")";
#endif
if (super_block.s_magic != EXT2_SUPER_MAGIC)
return false;
#if EXT2_DEBUG
klog() << "ext2fs: " << super_block.s_inodes_count << " inodes, " << super_block.s_blocks_count << " blocks";
klog() << "ext2fs: block size = " << EXT2_BLOCK_SIZE(&super_block);
klog() << "ext2fs: first data block = " << super_block.s_first_data_block;
klog() << "ext2fs: inodes per block = " << inodes_per_block();
klog() << "ext2fs: inodes per group = " << inodes_per_group();
klog() << "ext2fs: free inodes = " << super_block.s_free_inodes_count;
klog() << "ext2fs: desc per block = " << EXT2_DESC_PER_BLOCK(&super_block);
klog() << "ext2fs: desc size = " << EXT2_DESC_SIZE(&super_block);
#endif
set_block_size(EXT2_BLOCK_SIZE(&super_block));
ASSERT(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) {
klog() << "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());
auto result = read_blocks(first_block_of_bgdt, blocks_to_read, buffer);
if (result.is_error()) {
// FIXME: Propagate the error
dbgln("Ext2FS: initialize had error: {}", result.error());
return false;
}
#if EXT2_DEBUG
for (unsigned i = 1; i <= m_block_group_count; ++i) {
auto& group = group_descriptor(i);
klog() << "ext2fs: group[" << i << "] { block_bitmap: " << group.bg_block_bitmap << ", inode_bitmap: " << group.bg_inode_bitmap << ", inode_table: " << group.bg_inode_table << " }";
}
#endif
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(unsigned inode, unsigned& block_index, unsigned& offset) const
{
LOCKER(m_lock);
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 - 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);
blocks_remaining -= shape.indirect_blocks;
shape.meta_blocks += 1;
if (!blocks_remaining)
return shape;
shape.doubly_indirect_blocks = min(blocks_remaining, entries_per_block * entries_per_block);
blocks_remaining -= shape.doubly_indirect_blocks;
shape.meta_blocks += 1;
shape.meta_blocks += shape.doubly_indirect_blocks / entries_per_block;
if ((shape.doubly_indirect_blocks % entries_per_block) != 0)
shape.meta_blocks += 1;
if (!blocks_remaining)
return shape;
dbgln("we don't know how to compute tind ext2fs blocks yet!");
ASSERT_NOT_REACHED();
shape.triply_indirect_blocks = min(blocks_remaining, entries_per_block * entries_per_block * entries_per_block);
blocks_remaining -= shape.triply_indirect_blocks;
if (!blocks_remaining)
return shape;
ASSERT_NOT_REACHED();
return {};
}
KResult Ext2FS::write_block_list_for_inode(InodeIndex inode_index, ext2_inode& e2inode, const Vector<BlockIndex>& blocks)
{
LOCKER(m_lock);
if (blocks.is_empty()) {
e2inode.i_blocks = 0;
memset(e2inode.i_block, 0, sizeof(e2inode.i_block));
write_ext2_inode(inode_index, e2inode);
return KSuccess;
}
// NOTE: There is a mismatch between i_blocks and blocks.size() since i_blocks includes meta blocks and blocks.size() does not.
auto old_block_count = ceil_div(static_cast<size_t>(e2inode.i_size), block_size());
auto old_shape = compute_block_list_shape(old_block_count);
auto new_shape = compute_block_list_shape(blocks.size());
Vector<BlockIndex> new_meta_blocks;
if (new_shape.meta_blocks > old_shape.meta_blocks) {
new_meta_blocks = allocate_blocks(group_index_from_inode(inode_index), new_shape.meta_blocks - old_shape.meta_blocks);
}
e2inode.i_blocks = (blocks.size() + new_shape.meta_blocks) * (block_size() / 512);
bool inode_dirty = false;
unsigned output_block_index = 0;
unsigned remaining_blocks = blocks.size();
for (unsigned i = 0; i < new_shape.direct_blocks; ++i) {
if (e2inode.i_block[i] != blocks[output_block_index])
inode_dirty = true;
e2inode.i_block[i] = blocks[output_block_index];
++output_block_index;
--remaining_blocks;
}
if (inode_dirty) {
#if EXT2_DEBUG
dbgln("Ext2FS: Writing {} direct block(s) to i_block array of inode {}", min((size_t)EXT2_NDIR_BLOCKS, blocks.size()), inode_index);
for (size_t i = 0; i < min((size_t)EXT2_NDIR_BLOCKS, blocks.size()); ++i)
dbgln(" + {}", blocks[i]);
#endif
write_ext2_inode(inode_index, e2inode);
inode_dirty = false;
}
if (!remaining_blocks)
return KSuccess;
const unsigned entries_per_block = EXT2_ADDR_PER_BLOCK(&super_block());
bool ind_block_new = !e2inode.i_block[EXT2_IND_BLOCK];
if (ind_block_new) {
BlockIndex new_indirect_block = new_meta_blocks.take_last();
if (e2inode.i_block[EXT2_IND_BLOCK] != new_indirect_block)
inode_dirty = true;
e2inode.i_block[EXT2_IND_BLOCK] = new_indirect_block;
if (inode_dirty) {
#if EXT2_DEBUG
dbgln("Ext2FS: Adding the indirect block to i_block array of inode {}", inode_index);
#endif
write_ext2_inode(inode_index, e2inode);
inode_dirty = false;
}
}
if (old_shape.indirect_blocks == new_shape.indirect_blocks) {
// No need to update the singly indirect block array.
remaining_blocks -= new_shape.indirect_blocks;
output_block_index += new_shape.indirect_blocks;
} else {
auto block_contents = ByteBuffer::create_uninitialized(block_size());
OutputMemoryStream stream { block_contents };
ASSERT(new_shape.indirect_blocks <= entries_per_block);
for (unsigned i = 0; i < new_shape.indirect_blocks; ++i) {
stream << blocks[output_block_index++];
--remaining_blocks;
}
stream.fill_to_end(0);
auto buffer = UserOrKernelBuffer::for_kernel_buffer(stream.data());
auto result = write_block(e2inode.i_block[EXT2_IND_BLOCK], buffer, stream.size());
if (result.is_error())
return result;
}
if (!remaining_blocks)
return KSuccess;
bool dind_block_dirty = false;
bool dind_block_new = !e2inode.i_block[EXT2_DIND_BLOCK];
if (dind_block_new) {
BlockIndex new_dindirect_block = new_meta_blocks.take_last();
if (e2inode.i_block[EXT2_DIND_BLOCK] != new_dindirect_block)
inode_dirty = true;
e2inode.i_block[EXT2_DIND_BLOCK] = new_dindirect_block;
if (inode_dirty) {
#if EXT2_DEBUG
dbgln("Ext2FS: Adding the doubly-indirect block to i_block array of inode {}", inode_index);
#endif
write_ext2_inode(inode_index, e2inode);
inode_dirty = false;
}
}
if (old_shape.doubly_indirect_blocks == new_shape.doubly_indirect_blocks) {
// No need to update the doubly indirect block data.
remaining_blocks -= new_shape.doubly_indirect_blocks;
output_block_index += new_shape.doubly_indirect_blocks;
} else {
unsigned indirect_block_count = new_shape.doubly_indirect_blocks / entries_per_block;
if ((new_shape.doubly_indirect_blocks % entries_per_block) != 0)
indirect_block_count++;
auto dind_block_contents = ByteBuffer::create_uninitialized(block_size());
if (dind_block_new) {
memset(dind_block_contents.data(), 0, dind_block_contents.size());
dind_block_dirty = true;
} else {
auto buffer = UserOrKernelBuffer::for_kernel_buffer(dind_block_contents.data());
auto result = read_block(e2inode.i_block[EXT2_DIND_BLOCK], &buffer, block_size());
if (result.is_error()) {
dbgln("Ext2FS: write_block_list_for_inode had error: {}", result.error());
return result;
}
}
auto* dind_block_as_pointers = (unsigned*)dind_block_contents.data();
ASSERT(indirect_block_count <= entries_per_block);
for (unsigned i = 0; i < indirect_block_count; ++i) {
bool ind_block_dirty = false;
BlockIndex indirect_block_index = dind_block_as_pointers[i];
bool ind_block_new = !indirect_block_index;
if (ind_block_new) {
indirect_block_index = new_meta_blocks.take_last();
dind_block_as_pointers[i] = indirect_block_index;
dind_block_dirty = true;
}
auto ind_block_contents = ByteBuffer::create_uninitialized(block_size());
if (ind_block_new) {
memset(ind_block_contents.data(), 0, dind_block_contents.size());
ind_block_dirty = true;
} else {
auto buffer = UserOrKernelBuffer::for_kernel_buffer(ind_block_contents.data());
auto result = read_block(indirect_block_index, &buffer, block_size());
if (result.is_error()) {
dbgln("Ext2FS: write_block_list_for_inode had error: {}", result.error());
return result;
}
}
auto* ind_block_as_pointers = (unsigned*)ind_block_contents.data();
unsigned entries_to_write = new_shape.doubly_indirect_blocks - (i * entries_per_block);
if (entries_to_write > entries_per_block)
entries_to_write = entries_per_block;
ASSERT(entries_to_write <= entries_per_block);
for (unsigned j = 0; j < entries_to_write; ++j) {
BlockIndex output_block = blocks[output_block_index++];
if (ind_block_as_pointers[j] != output_block) {
ind_block_as_pointers[j] = output_block;
ind_block_dirty = true;
}
--remaining_blocks;
}
for (unsigned j = entries_to_write; j < entries_per_block; ++j) {
if (ind_block_as_pointers[j] != 0) {
ind_block_as_pointers[j] = 0;
ind_block_dirty = true;
}
}
if (ind_block_dirty) {
auto buffer = UserOrKernelBuffer::for_kernel_buffer(ind_block_contents.data());
int err = write_block(indirect_block_index, buffer, block_size());
ASSERT(err >= 0);
}
}
for (unsigned i = indirect_block_count; i < entries_per_block; ++i) {
if (dind_block_as_pointers[i] != 0) {
dind_block_as_pointers[i] = 0;
dind_block_dirty = true;
}
}
if (dind_block_dirty) {
auto buffer = UserOrKernelBuffer::for_kernel_buffer(dind_block_contents.data());
int err = write_block(e2inode.i_block[EXT2_DIND_BLOCK], buffer, block_size());
ASSERT(err >= 0);
}
}
if (!remaining_blocks)
return KSuccess;
// FIXME: Implement!
dbgln("we don't know how to write tind ext2fs blocks yet!");
ASSERT_NOT_REACHED();
}
Vector<Ext2FS::BlockIndex> Ext2FS::block_list_for_inode(const ext2_inode& e2inode, bool include_block_list_blocks) const
{
auto block_list = block_list_for_inode_impl(e2inode, include_block_list_blocks);
while (!block_list.is_empty() && block_list.last() == 0)
block_list.take_last();
return block_list;
}
Vector<Ext2FS::BlockIndex> Ext2FS::block_list_for_inode_impl(const ext2_inode& e2inode, bool include_block_list_blocks) const
{
LOCKER(m_lock);
unsigned entries_per_block = EXT2_ADDR_PER_BLOCK(&super_block());
unsigned block_count = ceil_div(static_cast<size_t>(e2inode.i_size), 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;
#if EXT2_DEBUG
dbgln("Ext2FS::block_list_for_inode(): i_size={}, i_blocks={}, block_count={}", e2inode.i_size, e2inode.i_blocks, block_count);
#endif
unsigned blocks_remaining = block_count;
if (include_block_list_blocks) {
auto shape = compute_block_list_shape(block_count);
blocks_remaining += shape.meta_blocks;
}
Vector<BlockIndex> list;
auto add_block = [&](BlockIndex 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 block_list_for_inode_impl finishes.
auto process_block_array = [&](unsigned array_block_index, auto&& callback) {
if (include_block_list_blocks)
add_block(array_block_index);
auto count = min(blocks_remaining, entries_per_block);
u32 array[count];
auto buffer = UserOrKernelBuffer::for_kernel_buffer((u8*)array);
auto result = read_block(array_block_index, &buffer, sizeof(array), 0);
if (result.is_error()) {
// FIXME: Stop here and propagate this error.
dbgln("Ext2FS: block_list_for_inode_impl had error: {}", result.error());
}
for (BlockIndex i = 0; i < count; ++i)
callback(array[i]);
};
process_block_array(e2inode.i_block[EXT2_IND_BLOCK], [&](unsigned block_index) {
add_block(block_index);
});
if (!blocks_remaining)
return list;
process_block_array(e2inode.i_block[EXT2_DIND_BLOCK], [&](unsigned block_index) {
process_block_array(block_index, [&](unsigned block_index2) {
add_block(block_index2);
});
});
if (!blocks_remaining)
return list;
process_block_array(e2inode.i_block[EXT2_TIND_BLOCK], [&](unsigned block_index) {
process_block_array(block_index, [&](unsigned block_index2) {
process_block_array(block_index2, [&](unsigned block_index3) {
add_block(block_index3);
});
});
});
return list;
}
void Ext2FS::free_inode(Ext2FSInode& inode)
{
LOCKER(m_lock);
ASSERT(inode.m_raw_inode.i_links_count == 0);
#if EXT2_DEBUG
dbgln("Ext2FS: Inode {} has no more links, time to delete!", inode.index());
#endif
// Mark all blocks used by this inode as free.
auto block_list = block_list_for_inode(inode.m_raw_inode, true);
for (auto block_index : block_list) {
ASSERT(block_index <= super_block().s_blocks_count);
if (block_index)
set_block_allocation_state(block_index, false);
}
// If the inode being freed is a directory, update block group directory counter.
if (inode.is_directory()) {
auto& bgd = const_cast<ext2_group_desc&>(group_descriptor(group_index_from_inode(inode.index())));
--bgd.bg_used_dirs_count;
dbgln("Ext2FS: Decremented bg_used_dirs_count to {}", bgd.bg_used_dirs_count);
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().tv_sec;
write_ext2_inode(inode.index(), inode.m_raw_inode);
// Mark the inode as free.
set_inode_allocation_state(inode.index(), false);
}
void Ext2FS::flush_block_group_descriptor_table()
{
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());
auto result = write_blocks(first_block_of_bgdt, blocks_to_write, buffer);
if (result.is_error())
dbgln("Ext2FS: flush_block_group_descriptor_table had error: {}", result.error());
}
void Ext2FS::flush_writes()
{
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());
auto result = write_block(cached_bitmap->bitmap_block_index, buffer, block_size());
if (result.is_error()) {
dbgln("Ext2FS: flush_writes() had error {}", result.error());
}
cached_bitmap->dirty = false;
#if EXT2_DEBUG
dbgln("Flushed bitmap block {}", cached_bitmap->bitmap_block_index);
#endif
}
}
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, unsigned index)
: Inode(fs, index)
{
}
Ext2FSInode::~Ext2FSInode()
{
if (m_raw_inode.i_links_count == 0)
fs().free_inode(*this);
}
InodeMetadata Ext2FSInode::metadata() const
{
LOCKER(m_lock);
InodeMetadata metadata;
metadata.inode = identifier();
metadata.size = m_raw_inode.i_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(m_lock);
#if EXT2_DEBUG
dbgln("Ext2FS: flush_metadata for inode {}", index());
#endif
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(m_lock);
ASSERT(inode.fsid() == fsid());
{
auto it = m_inode_cache.find(inode.index());
if (it != m_inode_cache.end())
return (*it).value;
}
if (!get_inode_allocation_state(inode.index())) {
m_inode_cache.set(inode.index(), nullptr);
return nullptr;
}
unsigned block_index;
unsigned offset;
if (!find_block_containing_inode(inode.index(), block_index, offset))
return {};
auto new_inode = adopt(*new Ext2FSInode(const_cast<Ext2FS&>(*this), inode.index()));
auto buffer = UserOrKernelBuffer::for_kernel_buffer(reinterpret_cast<u8*>(&new_inode->m_raw_inode));
auto result = read_block(block_index, &buffer, sizeof(ext2_inode), offset);
if (result.is_error()) {
// FIXME: Propagate the actual error.
return nullptr;
}
m_inode_cache.set(inode.index(), new_inode);
return new_inode;
}
ssize_t Ext2FSInode::read_bytes(off_t offset, ssize_t count, UserOrKernelBuffer& buffer, FileDescription* description) const
{
Locker inode_locker(m_lock);
ASSERT(offset >= 0);
if (m_raw_inode.i_size == 0)
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) {
ASSERT(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;
}
Locker fs_locker(fs().m_lock);
if (m_block_list.is_empty())
m_block_list = fs().block_list_for_inode(m_raw_inode);
if (m_block_list.is_empty()) {
klog() << "ext2fs: read_bytes: empty block list for inode " << index();
return -EIO;
}
bool allow_cache = !description || !description->is_direct();
const int block_size = fs().block_size();
size_t first_block_logical_index = offset / block_size;
size_t 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;
size_t remaining_count = min((off_t)count, (off_t)size() - offset);
#if EXT2_VERY_DEBUG
dbgln("Ext2FS: Reading up to {} bytes, {} bytes into inode {} to {}", count, offset, index(), buffer.user_or_kernel_ptr());
#endif
for (size_t bi = first_block_logical_index; remaining_count && bi <= last_block_logical_index; ++bi) {
auto block_index = m_block_list[bi];
ASSERT(block_index);
size_t offset_into_block = (bi == first_block_logical_index) ? offset_into_first_block : 0;
size_t num_bytes_to_copy = min(block_size - offset_into_block, remaining_count);
auto buffer_offset = buffer.offset(nread);
int err = fs().read_block(block_index, &buffer_offset, num_bytes_to_copy, offset_into_block, allow_cache);
if (err < 0) {
klog() << "ext2fs: read_bytes: read_block(" << block_index << ") failed (lbi: " << bi << ")";
return err;
}
remaining_count -= num_bytes_to_copy;
nread += num_bytes_to_copy;
}
return nread;
}
KResult Ext2FSInode::resize(u64 new_size)
{
u64 old_size = size();
if (old_size == new_size)
return KSuccess;
u64 block_size = fs().block_size();
size_t blocks_needed_before = ceil_div(old_size, block_size);
size_t blocks_needed_after = ceil_div(new_size, block_size);
#if EXT2_DEBUG
dbgln("Ext2FSInode::resize(): blocks needed before (size was {}): {}", old_size, blocks_needed_before);
dbgln("Ext2FSInode::resize(): blocks needed after (size is {}): {}", new_size, blocks_needed_after);
#endif
if (blocks_needed_after > blocks_needed_before) {
u32 additional_blocks_needed = blocks_needed_after - blocks_needed_before;
if (additional_blocks_needed > fs().super_block().s_free_blocks_count)
return ENOSPC;
}
Vector<Ext2FS::BlockIndex> block_list;
if (!m_block_list.is_empty())
block_list = m_block_list;
else
block_list = fs().block_list_for_inode(m_raw_inode);
if (blocks_needed_after > blocks_needed_before) {
auto new_blocks = fs().allocate_blocks(fs().group_index_from_inode(index()), blocks_needed_after - blocks_needed_before);
block_list.append(move(new_blocks));
} else if (blocks_needed_after < blocks_needed_before) {
#if EXT2_DEBUG
dbgln("Ext2FS: Shrinking inode {}. Old block list is {} entries:", index(), block_list.size());
for (auto block_index : block_list) {
dbgln(" # {}", block_index);
}
#endif
while (block_list.size() != blocks_needed_after) {
auto block_index = block_list.take_last();
if (block_index)
fs().set_block_allocation_state(block_index, false);
}
}
auto result = fs().write_block_list_for_inode(index(), m_raw_inode, block_list);
if (result.is_error())
return result;
m_raw_inode.i_size = new_size;
set_metadata_dirty(true);
m_block_list = move(block_list);
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.
size_t bytes_to_clear = new_size - old_size;
size_t clear_from = old_size;
u8 zero_buffer[PAGE_SIZE];
memset(zero_buffer, 0, sizeof(zero_buffer));
while (bytes_to_clear) {
auto nwritten = write_bytes(clear_from, min(sizeof(zero_buffer), bytes_to_clear), UserOrKernelBuffer::for_kernel_buffer(zero_buffer), nullptr);
if (nwritten < 0)
return KResult((ErrnoCode)-nwritten);
ASSERT(nwritten != 0);
bytes_to_clear -= nwritten;
clear_from += nwritten;
}
}
return KSuccess;
}
ssize_t Ext2FSInode::write_bytes(off_t offset, ssize_t count, const UserOrKernelBuffer& data, FileDescription* description)
{
ASSERT(offset >= 0);
ASSERT(count >= 0);
Locker inode_locker(m_lock);
Locker fs_locker(fs().m_lock);
auto result = prepare_to_write_data();
if (result.is_error())
return result;
if (is_symlink()) {
ASSERT(offset == 0);
if (max((size_t)(offset + count), (size_t)m_raw_inode.i_size) < max_inline_symlink_length) {
#if EXT2_DEBUG
dbgln("Ext2FS: write_bytes poking into i_block array for inline symlink '{}' ({} bytes)", data.copy_into_string(count), count);
#endif
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 size_t block_size = fs().block_size();
u64 old_size = size();
u64 new_size = max(static_cast<u64>(offset) + count, (u64)size());
auto resize_result = resize(new_size);
if (resize_result.is_error())
return resize_result;
if (m_block_list.is_empty())
m_block_list = fs().block_list_for_inode(m_raw_inode);
if (m_block_list.is_empty()) {
dbgln("Ext2FSInode::write_bytes(): empty block list for inode {}", index());
return -EIO;
}
size_t first_block_logical_index = offset / block_size;
size_t 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;
size_t remaining_count = min((off_t)count, (off_t)new_size - offset);
#if EXT2_VERY_DEBUG
dbgln("Ext2FS: Writing {} bytes, {} bytes into inode {} from {}", count, offset, index(), data.user_or_kernel_ptr());
#endif
for (size_t bi = first_block_logical_index; remaining_count && bi <= last_block_logical_index; ++bi) {
size_t offset_into_block = (bi == first_block_logical_index) ? offset_into_first_block : 0;
size_t num_bytes_to_copy = min(block_size - offset_into_block, remaining_count);
#if EXT2_VERY_DEBUG
dbgln("Ext2FS: Writing block {} (offset_into_block: {})", m_block_list[bi], offset_into_block);
#endif
auto result = fs().write_block(m_block_list[bi], data.offset(nwritten), num_bytes_to_copy, offset_into_block, allow_cache);
if (result.is_error()) {
dbgln("Ext2FS: write_block({}) failed (bi: {})", m_block_list[bi], bi);
return result;
}
remaining_count -= num_bytes_to_copy;
nwritten += num_bytes_to_copy;
}
#if EXT2_VERY_DEBUG
dbgln("Ext2FS: After write, i_size={}, i_blocks={} ({} blocks in list)", m_raw_inode.i_size, m_raw_inode.i_blocks, m_block_list.size());
#endif
if (old_size != new_size)
inode_size_changed(old_size, new_size);
inode_contents_changed(offset, count, data);
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;
}
}
KResult Ext2FSInode::traverse_as_directory(Function<bool(const FS::DirectoryEntryView&)> callback) const
{
LOCKER(m_lock);
ASSERT(is_directory());
#if EXT2_VERY_DEBUG
dbgln("Ext2FS: Traversing as directory: {}", index());
#endif
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) {
#if EXT2_VERY_DEBUG
dbgln("Ext2Inode::traverse_as_directory: {}, name_len: {}, rec_len: {}, file_type: {}, name: {}", entry->inode, entry->name_len, entry->rec_len, entry->file_type, StringView(entry->name, entry->name_len));
#endif
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(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;
#if EXT2_DEBUG
dbgln("Ext2FS: New directory inode {} contents to write (size {}, occupied {}):", index(), directory_size, occupied_size);
#endif
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;
#if EXT2_DEBUG
dbgln("* Inode: {}, name_len: {}, rec_len: {}, file_type: {}, name: {}", entry.inode.index(), u16(entry.name.length()), u16(record_length), u8(entry.file_type), entry.name);
#endif
stream << u32(entry.inode.index());
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);
auto buffer = UserOrKernelBuffer::for_kernel_buffer(stream.data());
ssize_t nwritten = write_bytes(0, stream.size(), buffer, nullptr);
if (nwritten < 0)
return KResult((ErrnoCode)-nwritten);
set_metadata_dirty(true);
if (static_cast<size_t>(nwritten) != 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(identifier(), name, mode, uid, gid);
return fs().create_inode(identifier(), name, mode, dev, uid, gid);
}
KResult Ext2FSInode::add_child(Inode& child, const StringView& name, mode_t mode)
{
LOCKER(m_lock);
ASSERT(is_directory());
if (name.length() > EXT2_NAME_LEN)
return ENAMETOOLONG;
#if EXT2_DEBUG
dbgln("Ext2FSInode::add_child: Adding inode {} with name '{}' and mode {:o} to directory {}", child.index(), name, mode, index());
#endif
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, entry.file_type });
return true;
});
if (result.is_error())
return result;
if (name_already_exists) {
dbgln("Ext2FSInode::add_child: Name '{}' already exists in inode {}", name, index());
return EEXIST;
}
result = child.increment_link_count();
if (result.is_error())
return result;
entries.empend(name, child.identifier(), 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(m_lock);
#if EXT2_DEBUG
dbgln("Ext2FSInode::remove_child('{}') in inode {}", name, index());
#endif
ASSERT(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 };
#if EXT2_DEBUG
dbgln("Ext2FSInode::remove_child(): Removing '{}' in directory {}", name, index());
#endif
Vector<Ext2FSDirectoryEntry> entries;
KResult result = traverse_as_directory([&](auto& entry) {
if (name != entry.name)
entries.append({ entry.name, entry.inode, 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(unsigned inode, const ext2_inode& e2inode)
{
LOCKER(m_lock);
unsigned 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;
}
Vector<Ext2FS::BlockIndex> Ext2FS::allocate_blocks(GroupIndex preferred_group_index, size_t count)
{
LOCKER(m_lock);
#if EXT2_DEBUG
dbgln("Ext2FS: allocate_blocks(preferred group: {}, count {})", preferred_group_index, count);
#endif
if (count == 0)
return {};
Vector<BlockIndex> blocks;
#if EXT2_DEBUG
dbgln("Ext2FS: allocate_blocks:");
#endif
blocks.ensure_capacity(count);
GroupIndex 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) {
if (group_descriptor(group_index).bg_free_blocks_count) {
found_a_group = true;
break;
}
}
}
ASSERT(found_a_group);
auto& bgd = group_descriptor(group_index);
auto& cached_bitmap = get_bitmap_block(bgd.bg_block_bitmap);
int blocks_in_group = min(blocks_per_group(), super_block().s_blocks_count);
auto block_bitmap = Bitmap::wrap(cached_bitmap.buffer.data(), blocks_in_group);
BlockIndex first_block_in_group = (group_index - 1) * blocks_per_group() + first_block_index();
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);
ASSERT(first_unset_bit_index.has_value());
#if EXT2_DEBUG
dbgln("Ext2FS: allocating free region of size: {} [{}]", free_region_size, group_index);
#endif
for (size_t i = 0; i < free_region_size; ++i) {
BlockIndex block_index = (first_unset_bit_index.value() + i) + first_block_in_group;
set_block_allocation_state(block_index, true);
blocks.unchecked_append(block_index);
#if EXT2_DEBUG
dbgln(" allocated > {}", block_index);
#endif
}
}
ASSERT(blocks.size() == count);
return blocks;
}
unsigned Ext2FS::find_a_free_inode(GroupIndex preferred_group)
{
LOCKER(m_lock);
#if EXT2_DEBUG
dbgln("Ext2FS: find_a_free_inode(preferred_group: {})", preferred_group);
#endif
unsigned group_index = 0;
// 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](GroupIndex group_index) {
auto& bgd = group_descriptor(group_index);
return bgd.bg_free_inodes_count && bgd.bg_free_blocks_count >= 1;
};
if (preferred_group && 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;
}
}
if (!group_index) {
dmesgln("Ext2FS: find_a_free_inode: no suitable group found for new inode");
return 0;
}
#if EXT2_DEBUG
dbgln("Ext2FS: find_a_free_inode: found suitable group [{}] for new inode :^)", group_index);
#endif
auto& bgd = group_descriptor(group_index);
unsigned inodes_in_group = min(inodes_per_group(), super_block().s_inodes_count);
unsigned first_free_inode_in_group = 0;
unsigned first_inode_in_group = (group_index - 1) * inodes_per_group() + 1;
auto& cached_bitmap = get_bitmap_block(bgd.bg_inode_bitmap);
auto inode_bitmap = Bitmap::wrap(cached_bitmap.buffer.data(), inodes_in_group);
for (size_t i = 0; i < inode_bitmap.size(); ++i) {
if (inode_bitmap.get(i))
continue;
first_free_inode_in_group = first_inode_in_group + i;
break;
}
if (!first_free_inode_in_group) {
klog() << "Ext2FS: first_free_inode_in_group returned no inode, despite bgd claiming there are inodes :(";
return 0;
}
unsigned inode = first_free_inode_in_group;
#if EXT2_DEBUG
dbgln("Ext2FS: found suitable inode {}", inode);
#endif
ASSERT(get_inode_allocation_state(inode) == false);
return inode;
}
Ext2FS::GroupIndex Ext2FS::group_index_from_block_index(BlockIndex block_index) const
{
if (!block_index)
return 0;
return (block_index - 1) / blocks_per_group() + 1;
}
unsigned Ext2FS::group_index_from_inode(unsigned inode) const
{
if (!inode)
return 0;
return (inode - 1) / inodes_per_group() + 1;
}
bool Ext2FS::get_inode_allocation_state(InodeIndex index) const
{
LOCKER(m_lock);
if (index == 0)
return true;
unsigned group_index = group_index_from_inode(index);
auto& bgd = group_descriptor(group_index);
unsigned index_in_group = index - ((group_index - 1) * inodes_per_group());
unsigned bit_index = (index_in_group - 1) % inodes_per_group();
auto& cached_bitmap = const_cast<Ext2FS&>(*this).get_bitmap_block(bgd.bg_inode_bitmap);
return cached_bitmap.bitmap(inodes_per_group()).get(bit_index);
}
bool Ext2FS::set_inode_allocation_state(InodeIndex inode_index, bool new_state)
{
LOCKER(m_lock);
unsigned group_index = group_index_from_inode(inode_index);
auto& bgd = group_descriptor(group_index);
unsigned index_in_group = inode_index - ((group_index - 1) * inodes_per_group());
unsigned bit_index = (index_in_group - 1) % inodes_per_group();
auto& cached_bitmap = get_bitmap_block(bgd.bg_inode_bitmap);
bool current_state = cached_bitmap.bitmap(inodes_per_group()).get(bit_index);
#if EXT2_DEBUG
dbgln("Ext2FS: set_inode_allocation_state({}) {} -> {}", inode_index, current_state, new_state);
#endif
if (current_state == new_state) {
ASSERT_NOT_REACHED();
return true;
}
cached_bitmap.bitmap(inodes_per_group()).set(bit_index, new_state);
cached_bitmap.dirty = true;
// Update superblock
if (new_state)
--m_super_block.s_free_inodes_count;
else
++m_super_block.s_free_inodes_count;
m_super_block_dirty = true;
// Update BGD
auto& mutable_bgd = const_cast<ext2_group_desc&>(bgd);
if (new_state)
--mutable_bgd.bg_free_inodes_count;
else
++mutable_bgd.bg_free_inodes_count;
m_block_group_descriptors_dirty = true;
return true;
}
Ext2FS::BlockIndex Ext2FS::first_block_index() const
{
return block_size() == 1024 ? 1 : 0;
}
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());
int err = read_block(bitmap_block_index, &buffer, block_size());
ASSERT(err >= 0);
m_cached_bitmaps.append(make<CachedBitmap>(bitmap_block_index, move(block)));
return *m_cached_bitmaps.last();
}
bool Ext2FS::set_block_allocation_state(BlockIndex block_index, bool new_state)
{
ASSERT(block_index != 0);
LOCKER(m_lock);
GroupIndex group_index = group_index_from_block_index(block_index);
auto& bgd = group_descriptor(group_index);
BlockIndex index_in_group = (block_index - first_block_index()) - ((group_index - 1) * blocks_per_group());
unsigned bit_index = index_in_group % blocks_per_group();
auto& cached_bitmap = get_bitmap_block(bgd.bg_block_bitmap);
bool current_state = cached_bitmap.bitmap(blocks_per_group()).get(bit_index);
#if EXT2_DEBUG
dbgln("Ext2FS: block {} state: {} -> {} (in bitmap block {})", block_index, current_state, new_state, bgd.bg_block_bitmap);
#endif
if (current_state == new_state) {
ASSERT_NOT_REACHED();
return true;
}
cached_bitmap.bitmap(blocks_per_group()).set(bit_index, new_state);
cached_bitmap.dirty = true;
// Update superblock
if (new_state)
--m_super_block.s_free_blocks_count;
else
++m_super_block.s_free_blocks_count;
m_super_block_dirty = true;
// Update BGD
auto& mutable_bgd = const_cast<ext2_group_desc&>(bgd);
if (new_state)
--mutable_bgd.bg_free_blocks_count;
else
++mutable_bgd.bg_free_blocks_count;
m_block_group_descriptors_dirty = true;
return true;
}
KResult Ext2FS::create_directory(InodeIdentifier parent_id, const String& name, mode_t mode, uid_t uid, gid_t gid)
{
LOCKER(m_lock);
ASSERT(parent_id.fsid() == fsid());
ASSERT(is_directory(mode));
auto inode_or_error = create_inode(parent_id, name, mode, 0, uid, gid);
if (inode_or_error.is_error())
return inode_or_error.error();
auto& inode = inode_or_error.value();
#if EXT2_DEBUG
dbgln("Ext2FS: create_directory: created new directory named '{} with inode {}", name, inode->index());
#endif
Vector<Ext2FSDirectoryEntry> entries;
entries.empend(".", inode->identifier(), static_cast<u8>(EXT2_FT_DIR));
entries.empend("..", parent_id, static_cast<u8>(EXT2_FT_DIR));
auto result = static_cast<Ext2FSInode&>(*inode).write_directory(entries);
if (result.is_error())
return result;
auto parent_inode = get_inode(parent_id);
result = parent_inode->increment_link_count();
if (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(InodeIdentifier parent_id, const String& name, mode_t mode, dev_t dev, uid_t uid, gid_t gid)
{
LOCKER(m_lock);
ASSERT(parent_id.fsid() == fsid());
auto parent_inode = get_inode(parent_id);
ASSERT(parent_inode);
if (static_cast<const Ext2FSInode&>(*parent_inode).m_raw_inode.i_links_count == 0)
return ENOENT;
if (name.length() > EXT2_NAME_LEN)
return ENAMETOOLONG;
#if EXT2_DEBUG
dbgln("Ext2FS: Adding inode '{}' (mode {:o}) to parent directory {}", name, mode, parent_inode->index());
#endif
// NOTE: This doesn't commit the inode allocation just yet!
auto inode_id = find_a_free_inode();
if (!inode_id) {
klog() << "Ext2FS: create_inode: allocate_inode failed";
return ENOSPC;
}
// Looks like we're good, time to update the inode bitmap and group+global inode counters.
bool success = set_inode_allocation_state(inode_id, true);
ASSERT(success);
struct timeval now;
kgettimeofday(now);
ext2_inode e2inode;
memset(&e2inode, 0, sizeof(ext2_inode));
e2inode.i_mode = mode;
e2inode.i_uid = uid;
e2inode.i_gid = gid;
e2inode.i_size = 0;
e2inode.i_atime = now.tv_sec;
e2inode.i_ctime = now.tv_sec;
e2inode.i_mtime = now.tv_sec;
e2inode.i_dtime = 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;
#if EXT2_DEBUG
dbgln("Ext2FS: writing initial metadata for inode {}", inode_id);
#endif
e2inode.i_flags = 0;
success = write_ext2_inode(inode_id, e2inode);
ASSERT(success);
// We might have cached the fact that this inode didn't exist. Wipe the slate.
m_inode_cache.remove(inode_id);
auto inode = get_inode({ fsid(), inode_id });
auto result = parent_inode->add_child(*inode, name, mode);
if (result.is_error())
return result;
return inode.release_nonnull();
}
bool Ext2FSInode::populate_lookup_cache() const
{
LOCKER(m_lock);
if (!m_lookup_cache.is_empty())
return true;
HashMap<String, unsigned> 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)
{
ASSERT(is_directory());
if (!populate_lookup_cache())
return {};
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 });
return {};
}
void Ext2FSInode::one_ref_left()
{
// FIXME: I would like to not live forever, but uncached Ext2FS is fucking painful right now.
}
int Ext2FSInode::set_atime(time_t t)
{
LOCKER(m_lock);
if (fs().is_readonly())
return -EROFS;
m_raw_inode.i_atime = t;
set_metadata_dirty(true);
return 0;
}
int Ext2FSInode::set_ctime(time_t t)
{
LOCKER(m_lock);
if (fs().is_readonly())
return -EROFS;
m_raw_inode.i_ctime = t;
set_metadata_dirty(true);
return 0;
}
int Ext2FSInode::set_mtime(time_t t)
{
LOCKER(m_lock);
if (fs().is_readonly())
return -EROFS;
m_raw_inode.i_mtime = t;
set_metadata_dirty(true);
return 0;
}
KResult Ext2FSInode::increment_link_count()
{
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(m_lock);
if (fs().is_readonly())
return EROFS;
ASSERT(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(m_lock);
m_inode_cache.remove(index);
}
KResultOr<size_t> Ext2FSInode::directory_entry_count() const
{
ASSERT(is_directory());
LOCKER(m_lock);
populate_lookup_cache();
return m_lookup_cache.size();
}
KResult Ext2FSInode::chmod(mode_t mode)
{
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(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(m_lock);
if (static_cast<u64>(m_raw_inode.i_size) == size)
return KSuccess;
auto result = resize(size);
if (result.is_error())
return result;
set_metadata_dirty(true);
return KSuccess;
}
KResultOr<int> Ext2FSInode::get_block_address(int index)
{
LOCKER(m_lock);
if (m_block_list.is_empty())
m_block_list = fs().block_list_for_inode(m_raw_inode);
if (index < 0 || (size_t)index >= m_block_list.size())
return 0;
return m_block_list[index];
}
unsigned Ext2FS::total_block_count() const
{
LOCKER(m_lock);
return super_block().s_blocks_count;
}
unsigned Ext2FS::free_block_count() const
{
LOCKER(m_lock);
return super_block().s_free_blocks_count;
}
unsigned Ext2FS::total_inode_count() const
{
LOCKER(m_lock);
return super_block().s_inodes_count;
}
unsigned Ext2FS::free_inode_count() const
{
LOCKER(m_lock);
return super_block().s_free_inodes_count;
}
KResult Ext2FS::prepare_to_unmount() const
{
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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