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ladybird/Kernel/Ext2FileSystem.cpp

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#include "Ext2FileSystem.h"
#include "ext2_fs.h"
#include "UnixTypes.h"
#include "RTC.h"
#include <AK/Bitmap.h>
#include <AK/StdLibExtras.h>
#include <AK/kmalloc.h>
#include <AK/ktime.h>
#include <AK/kstdio.h>
#include <AK/BufferStream.h>
#include <LibC/errno_numbers.h>
//#define EXT2_DEBUG
RetainPtr<Ext2FS> Ext2FS::create(RetainPtr<DiskDevice>&& device)
{
return adopt(*new Ext2FS(move(device)));
}
Ext2FS::Ext2FS(RetainPtr<DiskDevice>&& device)
: DiskBackedFS(move(device))
{
}
Ext2FS::~Ext2FS()
{
}
ByteBuffer Ext2FS::read_super_block() const
{
auto buffer = ByteBuffer::create_uninitialized(1024);
device().read_block(2, buffer.pointer());
device().read_block(3, buffer.offset_pointer(512));
return buffer;
}
bool Ext2FS::write_super_block(const ext2_super_block& sb)
{
const byte* raw = (const byte*)&sb;
bool success;
success = device().write_block(2, raw);
ASSERT(success);
success = device().write_block(3, raw + 512);
ASSERT(success);
// FIXME: This is an ugly way to refresh the superblock cache. :-|
super_block();
return true;
}
unsigned Ext2FS::first_block_of_group(unsigned groupIndex) const
{
return super_block().s_first_data_block + (groupIndex * super_block().s_blocks_per_group);
}
const ext2_super_block& Ext2FS::super_block() const
{
if (!m_cached_super_block)
m_cached_super_block = read_super_block();
return *reinterpret_cast<ext2_super_block*>(m_cached_super_block.pointer());
}
const ext2_group_desc& Ext2FS::group_descriptor(unsigned groupIndex) const
{
// FIXME: Should this fail gracefully somehow?
ASSERT(groupIndex <= m_block_group_count);
if (!m_cached_group_descriptor_table) {
unsigned blocks_to_read = ceil_div(m_block_group_count * (unsigned)sizeof(ext2_group_desc), block_size());
unsigned first_block_of_bgdt = block_size() == 1024 ? 2 : 1;
#ifdef EXT2_DEBUG
kprintf("ext2fs: block group count: %u, blocks-to-read: %u\n", m_block_group_count, blocks_to_read);
kprintf("ext2fs: first block of BGDT: %u\n", first_block_of_bgdt);
#endif
m_cached_group_descriptor_table = read_blocks(first_block_of_bgdt, blocks_to_read);
}
return reinterpret_cast<ext2_group_desc*>(m_cached_group_descriptor_table.pointer())[groupIndex - 1];
}
bool Ext2FS::initialize()
{
auto& super_block = this->super_block();
#ifdef EXT2_DEBUG
kprintf("ext2fs: super block magic: %x (super block size: %u)\n", super_block.s_magic, sizeof(ext2_super_block));
#endif
if (super_block.s_magic != EXT2_SUPER_MAGIC)
return false;
#ifdef EXT2_DEBUG
kprintf("ext2fs: %u inodes, %u blocks\n", super_block.s_inodes_count, super_block.s_blocks_count);
kprintf("ext2fs: block size = %u\n", EXT2_BLOCK_SIZE(&super_block));
kprintf("ext2fs: first data block = %u\n", super_block.s_first_data_block);
kprintf("ext2fs: inodes per block = %u\n", inodes_per_block());
kprintf("ext2fs: inodes per group = %u\n", inodes_per_group());
kprintf("ext2fs: free inodes = %u\n", super_block.s_free_inodes_count);
kprintf("ext2fs: desc per block = %u\n", EXT2_DESC_PER_BLOCK(&super_block));
kprintf("ext2fs: desc size = %u\n", EXT2_DESC_SIZE(&super_block));
#endif
set_block_size(EXT2_BLOCK_SIZE(&super_block));
m_block_group_count = ceil_div(super_block.s_blocks_count, super_block.s_blocks_per_group);
if (m_block_group_count == 0) {
kprintf("ext2fs: no block groups :(\n");
return false;
}
// Preheat the BGD cache.
group_descriptor(0);
#ifdef EXT2_DEBUG
for (unsigned i = 1; i <= m_block_group_count; ++i) {
auto& group = group_descriptor(i);
kprintf("ext2fs: group[%u] { block_bitmap: %u, inode_bitmap: %u, inode_table: %u }\n",
i,
group.bg_block_bitmap,
group.bg_inode_bitmap,
group.bg_inode_table);
}
#endif
return true;
}
const char* Ext2FS::class_name() const
{
return "Ext2FS";
}
InodeIdentifier Ext2FS::root_inode() const
{
return { fsid(), EXT2_ROOT_INO };
}
ByteBuffer Ext2FS::read_block_containing_inode(unsigned inode, unsigned& block_index, unsigned& offset) const
{
auto& super_block = this->super_block();
if (inode != EXT2_ROOT_INO && inode < EXT2_FIRST_INO(&super_block))
return { };
if (inode > super_block.s_inodes_count)
return { };
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 read_block(block_index);
}
Ext2FS::BlockListShape Ext2FS::compute_block_list_shape(unsigned blocks)
{
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;
ASSERT_NOT_REACHED();
// FIXME: Support dind/tind blocks.
shape.doubly_indirect_blocks = min(blocks_remaining, entries_per_block * 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);
blocks_remaining -= shape.triply_indirect_blocks;
// FIXME: What do we do for files >= 16GB?
ASSERT(!blocks_remaining);
return shape;
}
bool Ext2FS::write_block_list_for_inode(InodeIndex inode_index, ext2_inode& e2inode, const Vector<BlockIndex>& blocks)
{
dbgprintf("Ext2FS: writing %u block(s) to i_block array\n", min((size_t)EXT2_NDIR_BLOCKS, blocks.size()));
auto old_shape = compute_block_list_shape(e2inode.i_blocks / (2 << super_block().s_log_block_size));
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);
for (auto bi : new_meta_blocks)
set_block_allocation_state(group_index_from_inode(inode_index), bi, true);
}
e2inode.i_blocks = (blocks.size() + new_shape.meta_blocks) * (block_size() / 512);
unsigned output_block_index = 0;
unsigned remaining_blocks = blocks.size();
for (unsigned i = 0; i < new_shape.direct_blocks; ++i) {
e2inode.i_block[i] = blocks[output_block_index++];
--remaining_blocks;
}
write_ext2_inode(inode_index, e2inode);
if (!remaining_blocks)
return true;
if (!e2inode.i_block[EXT2_IND_BLOCK]) {
e2inode.i_block[EXT2_IND_BLOCK] = new_meta_blocks.take_last();
write_ext2_inode(inode_index, e2inode);
}
{
dbgprintf("Ext2FS: Writing out indirect blockptr block for inode %u\n", inode_index);
auto block_contents = ByteBuffer::create_uninitialized(block_size());
BufferStream stream(block_contents);
ASSERT(new_shape.indirect_blocks <= EXT2_ADDR_PER_BLOCK(&super_block()));
for (unsigned i = 0; i < new_shape.indirect_blocks; ++i) {
stream << blocks[output_block_index++];
--remaining_blocks;
}
stream.fill_to_end(0);
write_block(e2inode.i_block[EXT2_IND_BLOCK], block_contents);
}
if (!remaining_blocks)
return true;
// FIXME: Implement!
ASSERT_NOT_REACHED();
}
Vector<unsigned> Ext2FS::block_list_for_inode(const ext2_inode& e2inode, bool include_block_list_blocks) const
{
unsigned entries_per_block = EXT2_ADDR_PER_BLOCK(&super_block());
// NOTE: i_blocks is number of 512-byte blocks, not number of fs-blocks.
unsigned block_count = e2inode.i_blocks / (block_size() / 512);
unsigned blocksRemaining = block_count;
Vector<unsigned> list;
if (include_block_list_blocks) {
// This seems like an excessive over-estimate but w/e.
list.ensure_capacity(blocksRemaining * 2);
} else {
list.ensure_capacity(blocksRemaining);
}
unsigned direct_count = min(block_count, (unsigned)EXT2_NDIR_BLOCKS);
for (unsigned i = 0; i < direct_count; ++i) {
list.unchecked_append(e2inode.i_block[i]);
--blocksRemaining;
}
if (!blocksRemaining)
return list;
auto process_block_array = [&] (unsigned array_block_index, auto&& callback) {
if (include_block_list_blocks)
callback(array_block_index);
auto array_block = read_block(array_block_index);
ASSERT(array_block);
auto* array = reinterpret_cast<const __u32*>(array_block.pointer());
unsigned count = min(blocksRemaining, entries_per_block);
for (unsigned i = 0; i < count; ++i) {
if (!array[i]) {
blocksRemaining = 0;
return;
}
callback(array[i]);
--blocksRemaining;
}
};
process_block_array(e2inode.i_block[EXT2_IND_BLOCK], [&] (unsigned entry) {
list.unchecked_append(entry);
});
if (!blocksRemaining)
return list;
process_block_array(e2inode.i_block[EXT2_DIND_BLOCK], [&] (unsigned entry) {
process_block_array(entry, [&] (unsigned entry) {
list.unchecked_append(entry);
});
});
if (!blocksRemaining)
return list;
process_block_array(e2inode.i_block[EXT2_TIND_BLOCK], [&] (unsigned entry) {
process_block_array(entry, [&] (unsigned entry) {
process_block_array(entry, [&] (unsigned entry) {
list.unchecked_append(entry);
});
});
});
return list;
}
void Ext2FS::free_inode(Ext2FSInode& inode)
{
ASSERT(inode.m_raw_inode.i_links_count == 0);
dbgprintf("Ext2FS: inode %u has no more links, time to delete!\n", inode.index());
inode.m_raw_inode.i_dtime = RTC::now();
write_ext2_inode(inode.index(), inode.m_raw_inode);
auto block_list = block_list_for_inode(inode.m_raw_inode, true);
auto group_index = group_index_from_inode(inode.index());
for (auto block_index : block_list)
set_block_allocation_state(group_index, block_index, false);
set_inode_allocation_state(inode.index(), false);
if (inode.is_directory()) {
auto& bgd = const_cast<ext2_group_desc&>(group_descriptor(group_index_from_inode(inode.index())));
--bgd.bg_used_dirs_count;
dbgprintf("Ext2FS: decremented bg_used_dirs_count %u -> %u\n", bgd.bg_used_dirs_count - 1, bgd.bg_used_dirs_count);
flush_block_group_descriptor_table();
}
}
void Ext2FS::flush_block_group_descriptor_table()
{
unsigned blocks_to_write = ceil_div(m_block_group_count * (unsigned)sizeof(ext2_group_desc), block_size());
unsigned first_block_of_bgdt = block_size() == 1024 ? 2 : 1;
write_blocks(first_block_of_bgdt, blocks_to_write, m_cached_group_descriptor_table);
}
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
{
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 (::is_block_device(m_raw_inode.i_mode) || ::is_character_device(m_raw_inode.i_mode)) {
unsigned dev = m_raw_inode.i_block[0];
metadata.major_device = (dev & 0xfff00) >> 8;
metadata.minor_device = (dev & 0xff) | ((dev >> 12) & 0xfff00);
}
return metadata;
}
void Ext2FSInode::flush_metadata()
{
dbgprintf("Ext2FSInode: flush_metadata for inode %u\n", index());
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) {
LOCKER(m_lock);
// FIXME: This invalidation is way too hardcore. It's sad to throw away the whole cache.
m_lookup_cache.clear();
}
}
set_metadata_dirty(false);
}
RetainPtr<Inode> Ext2FS::get_inode(InodeIdentifier inode) const
{
ASSERT(inode.fsid() == fsid());
{
LOCKER(m_inode_cache_lock);
auto it = m_inode_cache.find(inode.index());
if (it != m_inode_cache.end())
return (*it).value;
}
if (!get_inode_allocation_state(inode.index())) {
LOCKER(m_inode_cache_lock);
m_inode_cache.set(inode.index(), nullptr);
return nullptr;
}
unsigned block_index;
unsigned offset;
auto block = read_block_containing_inode(inode.index(), block_index, offset);
if (!block)
return { };
LOCKER(m_inode_cache_lock);
auto it = m_inode_cache.find(inode.index());
if (it != m_inode_cache.end())
return (*it).value;
auto new_inode = adopt(*new Ext2FSInode(const_cast<Ext2FS&>(*this), inode.index()));
memcpy(&new_inode->m_raw_inode, reinterpret_cast<ext2_inode*>(block.offset_pointer(offset)), inode_size());
m_inode_cache.set(inode.index(), new_inode.copy_ref());
return new_inode;
}
ssize_t Ext2FSInode::read_bytes(off_t offset, size_t count, byte* buffer, FileDescriptor*) const
{
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.)
static const unsigned max_inline_symlink_length = 60;
if (is_symlink() && size() < max_inline_symlink_length) {
ssize_t nread = min((off_t)size() - offset, static_cast<off_t>(count));
memcpy(buffer, m_raw_inode.i_block + offset, nread);
return nread;
}
if (m_block_list.is_empty()) {
auto block_list = fs().block_list_for_inode(m_raw_inode);
LOCKER(m_lock);
if (m_block_list.size() != block_list.size())
m_block_list = move(block_list);
}
if (m_block_list.is_empty()) {
kprintf("ext2fs: read_bytes: empty block list for inode %u\n", index());
return -EIO;
}
const size_t block_size = fs().block_size();
dword first_block_logical_index = offset / block_size;
dword 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;
dword offset_into_first_block = offset % block_size;
ssize_t nread = 0;
size_t remaining_count = min((off_t)count, (off_t)size() - offset);
byte* out = buffer;
#ifdef EXT2_DEBUG
kprintf("Ext2FS: Reading up to %u bytes %d bytes into inode %u:%u to %p\n", count, offset, identifier().fsid(), identifier().index(), buffer);
//kprintf("ok let's do it, read(%u, %u) -> blocks %u thru %u, oifb: %u\n", offset, count, first_block_logical_index, last_block_logical_index, offset_into_first_block);
#endif
for (dword bi = first_block_logical_index; remaining_count && bi <= last_block_logical_index; ++bi) {
auto block = fs().read_block(m_block_list[bi]);
if (!block) {
kprintf("ext2fs: read_bytes: read_block(%u) failed (lbi: %u)\n", m_block_list[bi], bi);
return -EIO;
}
dword offset_into_block = (bi == first_block_logical_index) ? offset_into_first_block : 0;
dword num_bytes_to_copy = min(block_size - offset_into_block, remaining_count);
memcpy(out, block.pointer() + offset_into_block, num_bytes_to_copy);
remaining_count -= num_bytes_to_copy;
nread += num_bytes_to_copy;
out += num_bytes_to_copy;
}
return nread;
}
ssize_t Ext2FSInode::write_bytes(off_t offset, size_t count, const byte* data, FileDescriptor*)
{
LOCKER(m_lock);
// FIXME: Support writing to symlink inodes.
ASSERT(!is_symlink());
ASSERT(offset >= 0);
const size_t block_size = fs().block_size();
size_t new_size = max(static_cast<size_t>(offset) + count, size());
unsigned blocks_needed_before = ceil_div(size(), block_size);
unsigned blocks_needed_after = ceil_div(new_size, block_size);
auto 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);
for (auto new_block_index : new_blocks)
fs().set_block_allocation_state(fs().group_index_from_inode(index()), new_block_index, true);
block_list.append(move(new_blocks));
} else if (blocks_needed_after < blocks_needed_before) {
// FIXME: Implement block list shrinking!
ASSERT_NOT_REACHED();
}
dword first_block_logical_index = offset / block_size;
dword last_block_logical_index = (offset + count) / block_size;
if (last_block_logical_index >= block_list.size())
last_block_logical_index = block_list.size() - 1;
dword offset_into_first_block = offset % block_size;
ssize_t nwritten = 0;
size_t remaining_count = min((off_t)count, (off_t)new_size - offset);
const byte* in = data;
#ifdef EXT2_DEBUG
dbgprintf("Ext2FSInode::write_bytes: Writing %u bytes %d bytes into inode %u:%u from %p\n", count, offset, fsid(), index(), data);
#endif
auto buffer_block = ByteBuffer::create_uninitialized(block_size);
for (dword bi = first_block_logical_index; remaining_count && bi <= last_block_logical_index; ++bi) {
dword offset_into_block = (bi == first_block_logical_index) ? offset_into_first_block : 0;
dword num_bytes_to_copy = min(block_size - offset_into_block, remaining_count);
ByteBuffer block;
if (offset_into_block != 0) {
block = fs().read_block(block_list[bi]);
if (!block) {
kprintf("Ext2FSInode::write_bytes: read_block(%u) failed (lbi: %u)\n", block_list[bi], bi);
return -EIO;
}
} else
block = buffer_block;
memcpy(block.pointer() + offset_into_block, in, num_bytes_to_copy);
if (offset_into_block == 0 && !num_bytes_to_copy)
memset(block.pointer() + num_bytes_to_copy, 0, block_size - num_bytes_to_copy);
#ifdef EXT2_DEBUG
dbgprintf("Ext2FSInode::write_bytes: writing block %u (offset_into_block: %u)\n", block_list[bi], offset_into_block);
#endif
bool success = fs().write_block(block_list[bi], block);
if (!success) {
kprintf("Ext2FSInode::write_bytes: write_block(%u) failed (lbi: %u)\n", block_list[bi], bi);
return -EIO;
}
remaining_count -= num_bytes_to_copy;
nwritten += num_bytes_to_copy;
in += num_bytes_to_copy;
}
bool success = fs().write_block_list_for_inode(index(), m_raw_inode, block_list);
ASSERT(success);
m_raw_inode.i_size = new_size;
fs().write_ext2_inode(index(), m_raw_inode);
#ifdef EXT2_DEBUG
dbgprintf("Ext2FSInode::write_bytes: after write, i_size=%u, i_blocks=%u (%u blocks in list)\n", m_raw_inode.i_size, m_raw_inode.i_blocks, block_list.size());
#endif
// NOTE: Make sure the cached block list is up to date!
m_block_list = move(block_list);
return nwritten;
}
bool Ext2FSInode::traverse_as_directory(Function<bool(const FS::DirectoryEntry&)> callback) const
{
ASSERT(metadata().is_directory());
#ifdef EXT2_DEBUG
kprintf("Ext2Inode::traverse_as_directory: inode=%u:\n", index());
#endif
auto buffer = read_entire();
ASSERT(buffer);
auto* entry = reinterpret_cast<ext2_dir_entry_2*>(buffer.pointer());
while (entry < buffer.end_pointer()) {
if (entry->inode != 0) {
#ifdef EXT2_DEBUG
kprintf("Ext2Inode::traverse_as_directory: %u, name_len: %u, rec_len: %u, file_type: %u, name: %s\n", entry->inode, entry->name_len, entry->rec_len, entry->file_type, String(entry->name, entry->name_len).characters());
#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 true;
}
bool Ext2FSInode::add_child(InodeIdentifier child_id, const String& name, byte file_type, int& error)
{
ASSERT(is_directory());
//#ifdef EXT2_DEBUG
dbgprintf("Ext2FS: Adding inode %u with name '%s' to directory %u\n", child_id.index(), name.characters(), index());
//#endif
Vector<FS::DirectoryEntry> entries;
bool name_already_exists = false;
traverse_as_directory([&] (auto& entry) {
if (!strcmp(entry.name, name.characters())) {
name_already_exists = true;
return false;
}
entries.append(entry);
return true;
});
if (name_already_exists) {
kprintf("Ext2FS: Name '%s' already exists in directory inode %u\n", name.characters(), index());
error = -EEXIST;
return false;
}
entries.append({ name.characters(), name.length(), child_id, file_type });
bool success = fs().write_directory_inode(index(), move(entries));
if (success) {
LOCKER(m_lock);
m_lookup_cache.set(name, child_id.index());
}
return success;
}
bool Ext2FSInode::remove_child(const String& name, int& error)
{
#ifdef EXT2_DEBUG
dbgprintf("Ext2FSInode::remove_child(%s) in inode %u\n", name.characters(), index());
#endif
ASSERT(is_directory());
unsigned child_inode_index;
{
LOCKER(m_lock);
auto it = m_lookup_cache.find(name);
if (it == m_lookup_cache.end()) {
error = -ENOENT;
return false;
}
child_inode_index = (*it).value;
}
InodeIdentifier child_id { fsid(), child_inode_index };
//#ifdef EXT2_DEBUG
dbgprintf("Ext2FS: Removing '%s' in directory %u\n", name.characters(), index());
//#endif
Vector<FS::DirectoryEntry> entries;
traverse_as_directory([&] (auto& entry) {
if (entry.inode != child_id)
entries.append(entry);
return true;
});
bool success = fs().write_directory_inode(index(), move(entries));
if (!success) {
// FIXME: Plumb error from write_directory_inode().
error = -EIO;
return false;
}
{
LOCKER(m_lock);
m_lookup_cache.remove(name);
}
auto child_inode = fs().get_inode(child_id);
child_inode->decrement_link_count();
return success;
}
bool Ext2FS::write_directory_inode(unsigned directoryInode, Vector<DirectoryEntry>&& entries)
{
dbgprintf("Ext2FS: New directory inode %u contents to write:\n", directoryInode);
unsigned directory_size = 0;
for (auto& entry : entries) {
//kprintf(" - %08u %s\n", entry.inode.index(), entry.name);
directory_size += EXT2_DIR_REC_LEN(entry.name_length);
}
unsigned blocks_needed = ceil_div(directory_size, block_size());
unsigned occupied_size = blocks_needed * block_size();
dbgprintf("Ext2FS: directory size: %u (occupied: %u)\n", directory_size, occupied_size);
auto directory_data = ByteBuffer::create_uninitialized(occupied_size);
BufferStream stream(directory_data);
for (unsigned i = 0; i < entries.size(); ++i) {
auto& entry = entries[i];
unsigned record_length = EXT2_DIR_REC_LEN(entry.name_length);
if (i == entries.size() - 1)
record_length += occupied_size - directory_size;
dbgprintf("* inode: %u", entry.inode.index());
dbgprintf(", name_len: %u", word(entry.name_length));
dbgprintf(", rec_len: %u", word(record_length));
dbgprintf(", file_type: %u", byte(entry.file_type));
dbgprintf(", name: %s\n", entry.name);
stream << dword(entry.inode.index());
stream << word(record_length);
stream << byte(entry.name_length);
stream << byte(entry.file_type);
stream << entry.name;
unsigned padding = record_length - entry.name_length - 8;
//dbgprintf(" *** pad %u bytes\n", padding);
for (unsigned j = 0; j < padding; ++j) {
stream << byte(0);
}
}
stream.fill_to_end(0);
#if 0
kprintf("data to write (%u):\n", directory_data.size());
for (unsigned i = 0; i < directory_data.size(); ++i) {
kprintf("%02x ", directory_data[i]);
if ((i + 1) % 8 == 0)
kprintf(" ");
if ((i + 1) % 16 == 0)
kprintf("\n");
}
kprintf("\n");
#endif
auto directory_inode = get_inode({ fsid(), directoryInode });
ssize_t nwritten = directory_inode->write_bytes(0, directory_data.size(), directory_data.pointer(), nullptr);
return nwritten == directory_data.size();
}
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());
}
void Ext2FS::dump_block_bitmap(unsigned groupIndex) const
{
ASSERT(groupIndex <= m_block_group_count);
auto& bgd = group_descriptor(groupIndex);
unsigned blocks_in_group = min(blocks_per_group(), super_block().s_blocks_count);
unsigned block_count = ceil_div(blocks_in_group, 8u);
auto bitmap_blocks = read_blocks(bgd.bg_block_bitmap, block_count);
ASSERT(bitmap_blocks);
kprintf("ext2fs: group[%u] block bitmap (bitmap occupies %u blocks):\n", groupIndex, block_count);
auto bitmap = Bitmap::wrap(bitmap_blocks.pointer(), blocks_in_group);
for (unsigned i = 0; i < blocks_in_group; ++i) {
kprintf("%c", bitmap.get(i) ? '1' : '0');
}
kprintf("\n");
}
void Ext2FS::dump_inode_bitmap(unsigned groupIndex) const
{
traverse_inode_bitmap(groupIndex, [] (unsigned, const Bitmap& bitmap) {
for (unsigned i = 0; i < bitmap.size(); ++i)
kprintf("%c", bitmap.get(i) ? '1' : '0');
return true;
});
}
template<typename F>
void Ext2FS::traverse_inode_bitmap(unsigned groupIndex, F callback) const
{
ASSERT(groupIndex <= m_block_group_count);
auto& bgd = group_descriptor(groupIndex);
unsigned inodes_in_group = min(inodes_per_group(), super_block().s_inodes_count);
unsigned block_count = ceil_div(inodes_in_group, 8u);
for (unsigned i = 0; i < block_count; ++i) {
auto block = read_block(bgd.bg_inode_bitmap + i);
ASSERT(block);
bool should_continue = callback(i * (block_size() / 8) + 1, Bitmap::wrap(block.pointer(), inodes_in_group));
if (!should_continue)
break;
}
}
template<typename F>
void Ext2FS::traverse_block_bitmap(unsigned groupIndex, F callback) const
{
ASSERT(groupIndex <= m_block_group_count);
auto& bgd = group_descriptor(groupIndex);
unsigned blocks_in_group = min(blocks_per_group(), super_block().s_blocks_count);
unsigned block_count = ceil_div(blocks_in_group, 8u);
for (unsigned i = 0; i < block_count; ++i) {
auto block = read_block(bgd.bg_block_bitmap + i);
ASSERT(block);
bool should_continue = callback(i * (block_size() / 8) + 1, Bitmap::wrap(block.pointer(), blocks_in_group));
if (!should_continue)
break;
}
}
bool Ext2FS::write_ext2_inode(unsigned inode, const ext2_inode& e2inode)
{
unsigned block_index;
unsigned offset;
auto block = read_block_containing_inode(inode, block_index, offset);
if (!block)
return false;
memcpy(reinterpret_cast<ext2_inode*>(block.offset_pointer(offset)), &e2inode, inode_size());
write_block(block_index, block);
return true;
}
Vector<Ext2FS::BlockIndex> Ext2FS::allocate_blocks(unsigned group, unsigned count)
{
dbgprintf("Ext2FS: allocate_blocks(group: %u, count: %u)\n", group, count);
if (count == 0)
return { };
auto& bgd = group_descriptor(group);
if (bgd.bg_free_blocks_count < count) {
kprintf("Ext2FS: allocate_blocks can't allocate out of group %u, wanted %u but only %u available\n", group, count, bgd.bg_free_blocks_count);
return { };
}
// FIXME: Implement a scan that finds consecutive blocks if possible.
Vector<BlockIndex> blocks;
traverse_block_bitmap(group, [&blocks, count] (unsigned first_block_in_bitmap, const Bitmap& bitmap) {
for (unsigned i = 0; i < bitmap.size(); ++i) {
if (!bitmap.get(i)) {
blocks.append(first_block_in_bitmap + i);
if (blocks.size() == count)
return false;
}
}
return true;
});
dbgprintf("Ext2FS: allocate_block found these blocks:\n");
for (auto& bi : blocks) {
dbgprintf(" > %u\n", bi);
}
return blocks;
}
unsigned Ext2FS::allocate_inode(unsigned preferred_group, unsigned expected_size)
{
dbgprintf("Ext2FS: allocate_inode(preferredGroup: %u, expectedSize: %u)\n", preferred_group, expected_size);
unsigned needed_blocks = ceil_div(expected_size, block_size());
dbgprintf("Ext2FS: minimum needed blocks: %u\n", needed_blocks);
unsigned groupIndex = 0;
auto is_suitable_group = [this, needed_blocks] (unsigned groupIndex) {
auto& bgd = group_descriptor(groupIndex);
return bgd.bg_free_inodes_count && bgd.bg_free_blocks_count >= needed_blocks;
};
if (preferred_group && is_suitable_group(preferred_group)) {
groupIndex = preferred_group;
} else {
for (unsigned i = 1; i <= m_block_group_count; ++i) {
if (is_suitable_group(i))
groupIndex = i;
}
}
if (!groupIndex) {
kprintf("Ext2FS: allocate_inode: no suitable group found for new inode with %u blocks needed :(\n", needed_blocks);
return 0;
}
dbgprintf("Ext2FS: allocate_inode: found suitable group [%u] for new inode with %u blocks needed :^)\n", groupIndex, needed_blocks);
unsigned firstFreeInodeInGroup = 0;
traverse_inode_bitmap(groupIndex, [&firstFreeInodeInGroup] (unsigned firstInodeInBitmap, const Bitmap& bitmap) {
for (unsigned i = 0; i < bitmap.size(); ++i) {
if (!bitmap.get(i)) {
firstFreeInodeInGroup = firstInodeInBitmap + i;
return false;
}
}
return true;
});
if (!firstFreeInodeInGroup) {
kprintf("Ext2FS: first_free_inode_in_group returned no inode, despite bgd claiming there are inodes :(\n");
return 0;
}
unsigned inode = firstFreeInodeInGroup;
dbgprintf("Ext2FS: found suitable inode %u\n", inode);
// FIXME: allocate blocks if needed!
return inode;
}
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
{
if (index == 0)
return true;
auto& bgd = group_descriptor(group_index_from_inode(index));
unsigned inodes_per_bitmap_block = block_size() * 8;
unsigned bitmap_block_index = (index - 1) / inodes_per_bitmap_block;
unsigned bit_index = (index - 1) % inodes_per_bitmap_block;
auto block = read_block(bgd.bg_inode_bitmap + bitmap_block_index);
ASSERT(block);
auto bitmap = Bitmap::wrap(block.pointer(), block.size());
return bitmap.get(bit_index);
}
bool Ext2FS::set_inode_allocation_state(unsigned index, bool newState)
{
auto& bgd = group_descriptor(group_index_from_inode(index));
// Update inode bitmap
unsigned inodes_per_bitmap_block = block_size() * 8;
unsigned bitmap_block_index = (index - 1) / inodes_per_bitmap_block;
unsigned bit_index = (index - 1) % inodes_per_bitmap_block;
auto block = read_block(bgd.bg_inode_bitmap + bitmap_block_index);
ASSERT(block);
auto bitmap = Bitmap::wrap(block.pointer(), block.size());
bool current_state = bitmap.get(bit_index);
dbgprintf("Ext2FS: set_inode_allocation_state(%u) %u -> %u\n", index, current_state, newState);
if (current_state == newState)
return true;
bitmap.set(bit_index, newState);
write_block(bgd.bg_inode_bitmap + bitmap_block_index, block);
// Update superblock
auto& sb = *reinterpret_cast<ext2_super_block*>(m_cached_super_block.pointer());
dbgprintf("Ext2FS: superblock free inode count %u -> %u\n", sb.s_free_inodes_count, sb.s_free_inodes_count - 1);
if (newState)
--sb.s_free_inodes_count;
else
++sb.s_free_inodes_count;
write_super_block(sb);
// Update BGD
auto& mutable_bgd = const_cast<ext2_group_desc&>(bgd);
if (newState)
--mutable_bgd.bg_free_inodes_count;
else
++mutable_bgd.bg_free_inodes_count;
dbgprintf("Ext2FS: group free inode count %u -> %u\n", bgd.bg_free_inodes_count, bgd.bg_free_inodes_count - 1);
flush_block_group_descriptor_table();
return true;
}
bool Ext2FS::set_block_allocation_state(GroupIndex group, BlockIndex bi, bool new_state)
{
dbgprintf("Ext2FS: set_block_allocation_state(group=%u, block=%u, state=%u)\n", group, bi, new_state);
auto& bgd = group_descriptor(group);
// Update block bitmap
unsigned blocks_per_bitmap_block = block_size() * 8;
unsigned bitmap_block_index = (bi - 1) / blocks_per_bitmap_block;
unsigned bit_index = (bi - 1) % blocks_per_bitmap_block;
auto block = read_block(bgd.bg_block_bitmap + bitmap_block_index);
ASSERT(block);
auto bitmap = Bitmap::wrap(block.pointer(), blocks_per_bitmap_block);
bool current_state = bitmap.get(bit_index);
dbgprintf("Ext2FS: block %u state: %u -> %u\n", bi, current_state, new_state);
if (current_state == new_state)
return true;
bitmap.set(bit_index, new_state);
write_block(bgd.bg_block_bitmap + bitmap_block_index, block);
// Update superblock
auto& sb = *reinterpret_cast<ext2_super_block*>(m_cached_super_block.pointer());
dbgprintf("Ext2FS: superblock free block count %u -> %u\n", sb.s_free_blocks_count, sb.s_free_blocks_count - 1);
if (new_state)
--sb.s_free_blocks_count;
else
++sb.s_free_blocks_count;
write_super_block(sb);
// 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;
dbgprintf("Ext2FS: group free block count %u -> %u\n", bgd.bg_free_blocks_count, bgd.bg_free_blocks_count - 1);
flush_block_group_descriptor_table();
return true;
}
RetainPtr<Inode> Ext2FS::create_directory(InodeIdentifier parent_id, const String& name, mode_t mode, int& error)
{
ASSERT(parent_id.fsid() == fsid());
// Fix up the mode to definitely be a directory.
// FIXME: This is a bit on the hackish side.
mode &= ~0170000;
mode |= 0040000;
// NOTE: When creating a new directory, make the size 1 block.
// There's probably a better strategy here, but this works for now.
auto inode = create_inode(parent_id, name, mode, block_size(), error);
if (!inode)
return nullptr;
dbgprintf("Ext2FS: create_directory: created new directory named '%s' with inode %u\n", name.characters(), inode->identifier().index());
Vector<DirectoryEntry> entries;
entries.append({ ".", inode->identifier(), EXT2_FT_DIR });
entries.append({ "..", parent_id, EXT2_FT_DIR });
bool success = write_directory_inode(inode->identifier().index(), move(entries));
ASSERT(success);
auto parent_inode = get_inode(parent_id);
error = parent_inode->increment_link_count();
if (error < 0)
return nullptr;
auto& bgd = const_cast<ext2_group_desc&>(group_descriptor(group_index_from_inode(inode->identifier().index())));
++bgd.bg_used_dirs_count;
dbgprintf("Ext2FS: incremented bg_used_dirs_count %u -> %u\n", bgd.bg_used_dirs_count - 1, bgd.bg_used_dirs_count);
flush_block_group_descriptor_table();
error = 0;
return inode;
}
RetainPtr<Inode> Ext2FS::create_inode(InodeIdentifier parent_id, const String& name, mode_t mode, unsigned size, int& error)
{
ASSERT(parent_id.fsid() == fsid());
auto parent_inode = get_inode(parent_id);
dbgprintf("Ext2FS: Adding inode '%s' (mode %u) to parent directory %u:\n", name.characters(), mode, parent_inode->identifier().index());
// NOTE: This doesn't commit the inode allocation just yet!
auto inode_id = allocate_inode(0, size);
if (!inode_id) {
kprintf("Ext2FS: create_inode: allocate_inode failed\n");
error = -ENOSPC;
return { };
}
auto needed_blocks = ceil_div(size, block_size());
auto blocks = allocate_blocks(group_index_from_inode(inode_id), needed_blocks);
if (blocks.size() != needed_blocks) {
kprintf("Ext2FS: create_inode: allocate_blocks failed\n");
error = -ENOSPC;
return { };
}
byte file_type = 0;
if (is_regular_file(mode))
file_type = EXT2_FT_REG_FILE;
else if (is_directory(mode))
file_type = EXT2_FT_DIR;
else if (is_character_device(mode))
file_type = EXT2_FT_CHRDEV;
else if (is_block_device(mode))
file_type = EXT2_FT_BLKDEV;
else if (is_fifo(mode))
file_type = EXT2_FT_FIFO;
else if (is_socket(mode))
file_type = EXT2_FT_SOCK;
else if (is_symlink(mode))
file_type = EXT2_FT_SYMLINK;
// Try adding it to the directory first, in case the name is already in use.
bool success = parent_inode->add_child({ fsid(), inode_id }, name, file_type, error);
if (!success)
return { };
// Looks like we're good, time to update the inode bitmap and group+global inode counters.
success = set_inode_allocation_state(inode_id, true);
ASSERT(success);
for (auto bi : blocks) {
success = set_block_allocation_state(group_index_from_inode(inode_id), bi, true);
ASSERT(success);
}
unsigned initial_links_count;
if (is_directory(mode))
initial_links_count = 2; // (parent directory + "." entry in self)
else
initial_links_count = 1;
auto timestamp = RTC::now();
ext2_inode e2inode;
memset(&e2inode, 0, sizeof(ext2_inode));
e2inode.i_mode = mode;
e2inode.i_uid = 0;
e2inode.i_size = size;
e2inode.i_atime = timestamp;
e2inode.i_ctime = timestamp;
e2inode.i_mtime = timestamp;
e2inode.i_dtime = 0;
e2inode.i_gid = 0;
e2inode.i_links_count = initial_links_count;
success = write_block_list_for_inode(inode_id, e2inode, blocks);
ASSERT(success);
dbgprintf("Ext2FS: writing initial metadata for inode %u\n", inode_id);
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.
LOCKER(m_inode_cache_lock);
m_inode_cache.remove(inode_id);
}
return get_inode({ fsid(), inode_id });
}
RetainPtr<Inode> Ext2FSInode::parent() const
{
if (m_parent_id.is_valid())
return fs().get_inode(m_parent_id);
unsigned group_index = fs().group_index_from_inode(index());
unsigned first_inode_in_group = fs().inodes_per_group() * (group_index - 1);
Vector<RetainPtr<Ext2FSInode>> directories_in_group;
for (unsigned i = 0; i < fs().inodes_per_group(); ++i) {
auto group_member = fs().get_inode({ fsid(), first_inode_in_group + i });
if (!group_member)
continue;
if (group_member->is_directory())
directories_in_group.append(move(group_member));
}
for (auto& directory : directories_in_group) {
if (!directory->reverse_lookup(identifier()).is_null()) {
m_parent_id = directory->identifier();
break;
}
}
ASSERT(m_parent_id.is_valid());
return fs().get_inode(m_parent_id);
}
void Ext2FSInode::populate_lookup_cache() const
{
{
LOCKER(m_lock);
if (!m_lookup_cache.is_empty())
return;
}
HashMap<String, unsigned> children;
traverse_as_directory([&children] (auto& entry) {
children.set(String(entry.name, entry.name_length), entry.inode.index());
return true;
});
LOCKER(m_lock);
if (!m_lookup_cache.is_empty())
return;
m_lookup_cache = move(children);
}
InodeIdentifier Ext2FSInode::lookup(const String& name)
{
ASSERT(is_directory());
populate_lookup_cache();
LOCKER(m_lock);
auto it = m_lookup_cache.find(name);
if (it != m_lookup_cache.end())
return { fsid(), (*it).value };
return { };
}
String Ext2FSInode::reverse_lookup(InodeIdentifier child_id)
{
ASSERT(is_directory());
ASSERT(child_id.fsid() == fsid());
populate_lookup_cache();
LOCKER(m_lock);
for (auto it : m_lookup_cache) {
if (it.value == child_id.index())
return it.key;
}
return { };
}
void Ext2FSInode::one_retain_left()
{
// FIXME: I would like to not live forever, but uncached Ext2FS is fucking painful right now.
}
int Ext2FSInode::set_atime(time_t t)
{
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)
{
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)
{
if (fs().is_readonly())
return -EROFS;
m_raw_inode.i_mtime = t;
set_metadata_dirty(true);
return 0;
}
int Ext2FSInode::increment_link_count()
{
if (fs().is_readonly())
return -EROFS;
++m_raw_inode.i_links_count;
set_metadata_dirty(true);
return 0;
}
int Ext2FSInode::decrement_link_count()
{
if (fs().is_readonly())
return -EROFS;
ASSERT(m_raw_inode.i_links_count);
--m_raw_inode.i_links_count;
if (m_raw_inode.i_links_count == 0)
fs().uncache_inode(index());
set_metadata_dirty(true);
return 0;
}
void Ext2FS::uncache_inode(InodeIndex index)
{
LOCKER(m_inode_cache_lock);
m_inode_cache.remove(index);
}
size_t Ext2FSInode::directory_entry_count() const
{
ASSERT(is_directory());
populate_lookup_cache();
LOCKER(m_lock);
return m_lookup_cache.size();
}
bool Ext2FSInode::chmod(mode_t mode, int& error)
{
error = 0;
if (m_raw_inode.i_mode == mode)
return true;
m_raw_inode.i_mode = mode;
set_metadata_dirty(true);
return true;
}
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