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ladybird/Kernel/FileSystem/Ext2FileSystem.cpp
Andreas Kling 5254a320d8 Kernel: Remove use of copy_ref() in favor of regular RefPtr copies. 
This is obviously more readable. If we ever run into a situation where
ref count churn is actually causing trouble in the future, we can deal with
it then. For now, let's keep it simple. :^)
2019-07-11 15:40:04 +02:00

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#include <AK/Bitmap.h>
#include <AK/BufferStream.h>
#include <AK/StdLibExtras.h>
#include <Kernel/FileSystem/Ext2FileSystem.h>
#include <Kernel/FileSystem/ext2_fs.h>
#include <Kernel/Process.h>
#include <Kernel/RTC.h>
#include <Kernel/UnixTypes.h>
#include <LibC/errno_numbers.h>
//#define EXT2_DEBUG
static const ssize_t max_inline_symlink_length = 60;
static u8 to_ext2_file_type(mode_t mode)
{
if (is_regular_file(mode))
return EXT2_FT_REG_FILE;
if (is_directory(mode))
return EXT2_FT_DIR;
if (is_character_device(mode))
return EXT2_FT_CHRDEV;
if (is_block_device(mode))
return EXT2_FT_BLKDEV;
if (is_fifo(mode))
return EXT2_FT_FIFO;
if (is_socket(mode))
return EXT2_FT_SOCK;
if (is_symlink(mode))
return EXT2_FT_SYMLINK;
return EXT2_FT_UNKNOWN;
}
NonnullRefPtr<Ext2FS> Ext2FS::create(NonnullRefPtr<DiskDevice> device)
{
return adopt(*new Ext2FS(move(device)));
}
Ext2FS::Ext2FS(NonnullRefPtr<DiskDevice>&& device)
: DiskBackedFS(move(device))
{
}
Ext2FS::~Ext2FS()
{
}
ByteBuffer Ext2FS::read_super_block() const
{
LOCKER(m_lock);
auto buffer = ByteBuffer::create_uninitialized(1024);
bool success = device().read_block(2, buffer.pointer());
ASSERT(success);
success = device().read_block(3, buffer.offset_pointer(512));
ASSERT(success);
return buffer;
}
bool Ext2FS::write_super_block(const ext2_super_block& sb)
{
LOCKER(m_lock);
const u8* raw = (const u8*)&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(GroupIndex group_index) const
{
return super_block().s_first_data_block + (group_index * 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(GroupIndex group_index) const
{
// FIXME: Should this fail gracefully somehow?
ASSERT(group_index <= m_block_group_count);
if (!m_cached_group_descriptor_table) {
LOCKER(m_lock);
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())[group_index - 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
{
LOCKER(m_lock);
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)
{
LOCKER(m_lock);
// 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(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);
for (auto block_index : new_meta_blocks)
set_block_allocation_state(block_index, true);
}
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) {
dbgprintf("Ext2FS: Writing %u direct block(s) to i_block array of inode %u\n", min(EXT2_NDIR_BLOCKS, blocks.size()), inode_index);
#ifdef EXT2_DEBUG
for (int i = 0; i < min(EXT2_NDIR_BLOCKS, blocks.size()); ++i)
dbgprintf(" + %u\n", blocks[i]);
#endif
write_ext2_inode(inode_index, e2inode);
inode_dirty = false;
}
if (!remaining_blocks)
return true;
if (!e2inode.i_block[EXT2_IND_BLOCK]) {
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) {
dbgprintf("Ext2FS: Adding the indirect block to i_block array of inode %u\n", inode_index);
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;
} else {
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);
bool success = write_block(e2inode.i_block[EXT2_IND_BLOCK], block_contents);
ASSERT(success);
}
if (!remaining_blocks)
return true;
// FIXME: Implement!
ASSERT_NOT_REACHED();
}
Vector<Ext2FS::BlockIndex> Ext2FS::block_list_for_inode(const ext2_inode& e2inode, bool include_block_list_blocks) const
{
LOCKER(m_lock);
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);
#ifdef EXT2_DEBUG
dbgprintf("Ext2FS::block_list_for_inode(): i_size=%u, i_blocks=%u, block_count=%u\n", e2inode.i_size, block_count);
#endif
unsigned blocks_remaining = block_count;
Vector<BlockIndex> list;
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];
if (!block_index)
return list;
list.unchecked_append(block_index);
--blocks_remaining;
}
if (!blocks_remaining)
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(blocks_remaining, entries_per_block);
for (unsigned i = 0; i < count; ++i) {
if (!array[i]) {
blocks_remaining = 0;
return;
}
callback(array[i]);
--blocks_remaining;
}
};
process_block_array(e2inode.i_block[EXT2_IND_BLOCK], [&](unsigned entry) {
list.unchecked_append(entry);
});
if (!blocks_remaining)
return list;
process_block_array(e2inode.i_block[EXT2_DIND_BLOCK], [&](unsigned entry) {
process_block_array(entry, [&](unsigned entry) {
list.unchecked_append(entry);
});
});
if (!blocks_remaining)
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)
{
LOCKER(m_lock);
ASSERT(inode.m_raw_inode.i_links_count == 0);
dbgprintf("Ext2FS: inode %u has no more links, time to delete!\n", inode.index());
struct timeval now;
kgettimeofday(now);
inode.m_raw_inode.i_dtime = now.tv_sec;
write_ext2_inode(inode.index(), inode.m_raw_inode);
auto block_list = block_list_for_inode(inode.m_raw_inode, true);
for (auto block_index : block_list)
set_block_allocation_state(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()
{
LOCKER(m_lock);
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
{
// FIXME: This should probably take the inode lock, no?
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_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);
}
if (::is_block_device(m_raw_inode.i_mode)) {
unsigned 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);
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) {
// 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;
auto block = read_block_containing_inode(inode.index(), block_index, offset);
if (!block)
return {};
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)), sizeof(ext2_inode));
m_inode_cache.set(inode.index(), new_inode);
return new_inode;
}
ssize_t Ext2FSInode::read_bytes(off_t offset, ssize_t count, u8* buffer, FileDescription*) 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) {
ssize_t nread = min((off_t)size() - offset, static_cast<off_t>(count));
memcpy(buffer, ((const u8*)m_raw_inode.i_block) + offset, (size_t)nread);
return nread;
}
Locker fs_locker(fs().m_lock);
if (m_block_list.is_empty()) {
auto block_list = fs().block_list_for_inode(m_raw_inode);
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 int block_size = fs().block_size();
int first_block_logical_index = offset / block_size;
int 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;
int remaining_count = min((off_t)count, (off_t)size() - offset);
u8* 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 (int 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;
}
int offset_into_block = (bi == first_block_logical_index) ? offset_into_first_block : 0;
int 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;
}
bool Ext2FSInode::resize(u64 new_size)
{
u64 block_size = fs().block_size();
u64 old_size = size();
int blocks_needed_before = ceil_div(old_size, block_size);
int blocks_needed_after = ceil_div(new_size, block_size);
#ifdef EXT2_DEBUG
dbgprintf("Ext2FSInode::resize(): blocks needed before (size was %Q): %d\n", old_size, blocks_needed_before);
dbgprintf("Ext2FSInode::resize(): blocks needed after (size is %Q): %d\n", new_size, blocks_needed_after);
#endif
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(new_block_index, true);
block_list.append(move(new_blocks));
} else if (blocks_needed_after < blocks_needed_before) {
#ifdef EXT2_DEBUG
dbgprintf("Ext2FSInode::resize(): Shrinking. Old block list is %d entries:\n", block_list.size());
for (auto block_index : block_list) {
dbgprintf(" # %u\n", block_index);
}
#endif
while (block_list.size() != blocks_needed_after) {
auto block_index = block_list.take_last();
fs().set_block_allocation_state(block_index, false);
}
}
bool success = fs().write_block_list_for_inode(index(), m_raw_inode, block_list);
if (!success)
return false;
m_raw_inode.i_size = new_size;
set_metadata_dirty(true);
m_block_list = move(block_list);
return true;
}
ssize_t Ext2FSInode::write_bytes(off_t offset, ssize_t count, const u8* data, FileDescription*)
{
ASSERT(offset >= 0);
ASSERT(count >= 0);
Locker inode_locker(m_lock);
Locker fs_locker(fs().m_lock);
if (is_symlink()) {
if ((offset + count) < max_inline_symlink_length) {
#ifdef EXT2_DEBUG
dbgprintf("Ext2FSInode: write_bytes poking into i_block array for inline symlink '%s' (%u bytes)\n", String((const char*)data, count).characters(), count);
#endif
memcpy(((u8*)m_raw_inode.i_block) + offset, data, (size_t)count);
if ((offset + count) > (off_t)m_raw_inode.i_size)
m_raw_inode.i_size = offset + count;
set_metadata_dirty(true);
return count;
}
}
const ssize_t block_size = fs().block_size();
u64 old_size = size();
u64 new_size = max(static_cast<u64>(offset) + count, (u64)size());
if (!resize(new_size))
return -EIO;
int first_block_logical_index = offset / block_size;
int 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;
int last_logical_block_index_in_file = new_size / block_size;
ssize_t nwritten = 0;
int remaining_count = min((off_t)count, (off_t)new_size - offset);
const u8* 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 (int bi = first_block_logical_index; remaining_count && bi <= last_block_logical_index; ++bi) {
int offset_into_block = (bi == first_block_logical_index) ? offset_into_first_block : 0;
int num_bytes_to_copy = min(block_size - offset_into_block, remaining_count);
ByteBuffer block;
if (offset_into_block != 0 || num_bytes_to_copy != block_size) {
block = fs().read_block(m_block_list[bi]);
if (!block) {
kprintf("Ext2FSInode::write_bytes: read_block(%u) failed (lbi: %u)\n", m_block_list[bi], bi);
return -EIO;
}
} else
block = buffer_block;
memcpy(block.pointer() + offset_into_block, in, num_bytes_to_copy);
if (bi == last_logical_block_index_in_file && num_bytes_to_copy < block_size) {
int padding_start = new_size % block_size;
int padding_bytes = block_size - padding_start;
#ifdef EXT2_DEBUG
dbgprintf("Ext2FSInode::write_bytes padding last block of file with zero x %u (new_size=%u, offset_into_block=%u, num_bytes_to_copy=%u)\n", padding_bytes, new_size, offset_into_block, num_bytes_to_copy);
#endif
memset(block.pointer() + padding_start, 0, padding_bytes);
}
#ifdef EXT2_DEBUG
dbgprintf("Ext2FSInode::write_bytes: writing block %u (offset_into_block: %u)\n", m_block_list[bi], offset_into_block);
#endif
bool success = fs().write_block(m_block_list[bi], block);
if (!success) {
kprintf("Ext2FSInode::write_bytes: write_block(%u) failed (lbi: %u)\n", m_block_list[bi], bi);
ASSERT_NOT_REACHED();
return -EIO;
}
remaining_count -= num_bytes_to_copy;
nwritten += num_bytes_to_copy;
in += num_bytes_to_copy;
}
#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, 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;
}
bool Ext2FSInode::traverse_as_directory(Function<bool(const FS::DirectoryEntry&)> callback) const
{
LOCKER(m_lock);
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::write_directory(const Vector<FS::DirectoryEntry>& entries)
{
LOCKER(m_lock);
dbgprintf("Ext2FS: New directory inode %u contents to write:\n", index());
int 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);
}
auto block_size = fs().block_size();
int blocks_needed = ceil_div(directory_size, block_size);
int 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 (int 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;
dbgprintf("* inode: %u", entry.inode.index());
dbgprintf(", name_len: %u", u16(entry.name_length));
dbgprintf(", rec_len: %u", u16(record_length));
dbgprintf(", file_type: %u", u8(entry.file_type));
dbgprintf(", name: %s\n", entry.name);
stream << u32(entry.inode.index());
stream << u16(record_length);
stream << u8(entry.name_length);
stream << u8(entry.file_type);
stream << entry.name;
int padding = record_length - entry.name_length - 8;
for (int j = 0; j < padding; ++j)
stream << u8(0);
}
stream.fill_to_end(0);
ssize_t nwritten = write_bytes(0, directory_data.size(), directory_data.pointer(), nullptr);
return nwritten == directory_data.size();
}
KResult Ext2FSInode::add_child(InodeIdentifier child_id, const StringView& name, mode_t mode)
{
LOCKER(m_lock);
ASSERT(is_directory());
//#ifdef EXT2_DEBUG
dbg() << "Ext2FSInode::add_child(): Adding inode " << child_id.index() << " with name '" << name << " and mode " << mode << " to directory " << index();
//#endif
Vector<FS::DirectoryEntry> entries;
bool name_already_exists = false;
traverse_as_directory([&](auto& entry) {
if (name == entry.name) {
name_already_exists = true;
return false;
}
entries.append(entry);
return true;
});
if (name_already_exists) {
dbg() << "Ext2FSInode::add_child(): Name '" << name << "' already exists in inode " << index();
return KResult(-EEXIST);
}
auto child_inode = fs().get_inode(child_id);
if (child_inode)
child_inode->increment_link_count();
entries.append({ name.characters_without_null_termination(), name.length(), child_id, to_ext2_file_type(mode) });
bool success = write_directory(entries);
if (success)
m_lookup_cache.set(name, child_id.index());
return KSuccess;
}
KResult Ext2FSInode::remove_child(const StringView& name)
{
LOCKER(m_lock);
#ifdef EXT2_DEBUG
dbg() << "Ext2FSInode::remove_child(" << name << ") in inode " << index();
#endif
ASSERT(is_directory());
unsigned child_inode_index;
auto it = m_lookup_cache.find(name);
if (it == m_lookup_cache.end())
return KResult(-ENOENT);
child_inode_index = (*it).value;
InodeIdentifier child_id { fsid(), child_inode_index };
//#ifdef EXT2_DEBUG
dbg() << "Ext2FSInode::remove_child(): Removing '" << name << "' in directory " << index();
//#endif
Vector<FS::DirectoryEntry> entries;
traverse_as_directory([&](auto& entry) {
if (name != entry.name)
entries.append(entry);
return true;
});
bool success = write_directory(entries);
if (!success) {
// FIXME: Plumb error from write_directory().
return KResult(-EIO);
}
m_lookup_cache.remove(name);
auto child_inode = fs().get_inode(child_id);
child_inode->decrement_link_count();
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;
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());
bool success = write_block(block_index, block);
ASSERT(success);
return success;
}
Vector<Ext2FS::BlockIndex> Ext2FS::allocate_blocks(GroupIndex group_index, int count)
{
LOCKER(m_lock);
dbgprintf("Ext2FS: allocate_blocks(group: %u, count: %u)\n", group_index, count);
if (count == 0)
return {};
auto& bgd = group_descriptor(group_index);
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_index, count, bgd.bg_free_blocks_count);
return {};
}
// FIXME: Implement a scan that finds consecutive blocks if possible.
Vector<BlockIndex> blocks;
auto bitmap_block = read_block(bgd.bg_block_bitmap);
int blocks_in_group = min(blocks_per_group(), super_block().s_blocks_count);
auto block_bitmap = Bitmap::wrap(bitmap_block.pointer(), blocks_in_group);
BlockIndex first_block_in_group = (group_index - 1) * blocks_per_group() + 1;
for (int i = 0; i < block_bitmap.size(); ++i) {
if (!block_bitmap.get(i)) {
blocks.append(first_block_in_group + i);
if (blocks.size() == count)
break;
}
}
ASSERT(blocks.size() == count);
dbgprintf("Ext2FS: allocate_block found these blocks:\n");
for (auto& bi : blocks) {
dbgprintf(" > %u\n", bi);
}
return blocks;
}
unsigned Ext2FS::allocate_inode(GroupIndex preferred_group, off_t expected_size)
{
LOCKER(m_lock);
dbgprintf("Ext2FS: allocate_inode(preferredGroup: %u, expected_size: %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 group_index = 0;
auto is_suitable_group = [this, needed_blocks](GroupIndex group_index) {
auto& bgd = group_descriptor(group_index);
return bgd.bg_free_inodes_count && bgd.bg_free_blocks_count >= needed_blocks;
};
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) {
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", group_index, needed_blocks);
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 bitmap_block = read_block(bgd.bg_inode_bitmap);
auto inode_bitmap = Bitmap::wrap(bitmap_block.data(), inodes_in_group);
for (int 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) {
kprintf("Ext2FS: first_free_inode_in_group returned no inode, despite bgd claiming there are inodes :(\n");
return 0;
}
unsigned inode = first_free_inode_in_group;
dbgprintf("Ext2FS: found suitable inode %u\n", inode);
ASSERT(get_inode_allocation_state(inode) == false);
// FIXME: allocate blocks if needed!
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 block = read_block(bgd.bg_inode_bitmap);
ASSERT(block);
auto bitmap = Bitmap::wrap(block.pointer(), inodes_per_group());
return bitmap.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 block = read_block(bgd.bg_inode_bitmap);
ASSERT(block);
auto bitmap = Bitmap::wrap(block.pointer(), inodes_per_group());
bool current_state = bitmap.get(bit_index);
dbgprintf("Ext2FS: set_inode_allocation_state(%u) %u -> %u\n", inode_index, current_state, new_state);
if (current_state == new_state) {
ASSERT_NOT_REACHED();
return true;
}
bitmap.set(bit_index, new_state);
bool success = write_block(bgd.bg_inode_bitmap, block);
ASSERT(success);
// 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 (new_state)
--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 (new_state)
--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(BlockIndex block_index, bool new_state)
{
LOCKER(m_lock);
#ifdef EXT2_DEBUG
dbgprintf("Ext2FS: set_block_allocation_state(block=%u, state=%u)\n", block_index, new_state);
#endif
unsigned group_index = group_index_from_block_index(block_index);
auto& bgd = group_descriptor(group_index);
BlockIndex index_in_group = (block_index - 1) - ((group_index - 1) * blocks_per_group());
unsigned bit_index = index_in_group % blocks_per_group();
#ifdef EXT2_DEBUG
dbgprintf(" index_in_group: %u\n", index_in_group);
dbgprintf(" blocks_per_group: %u\n", blocks_per_group());
dbgprintf(" bit_index: %u\n", bit_index);
dbgprintf(" read_block(%u)\n", bgd.bg_block_bitmap);
#endif
auto block = read_block(bgd.bg_block_bitmap);
ASSERT(block);
auto bitmap = Bitmap::wrap(block.pointer(), blocks_per_group());
bool current_state = bitmap.get(bit_index);
dbgprintf("Ext2FS: block %u state: %u -> %u\n", block_index, current_state, new_state);
if (current_state == new_state) {
ASSERT_NOT_REACHED();
return true;
}
bitmap.set(bit_index, new_state);
bool success = write_block(bgd.bg_block_bitmap, block);
ASSERT(success);
// 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 %u free block count %u -> %u\n", group_index, bgd.bg_free_blocks_count, bgd.bg_free_blocks_count - 1);
flush_block_group_descriptor_table();
return true;
}
RefPtr<Inode> Ext2FS::create_directory(InodeIdentifier parent_id, const String& name, mode_t mode, int& error)
{
LOCKER(m_lock);
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(), 0, 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 = static_cast<Ext2FSInode&>(*inode).write_directory(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;
}
RefPtr<Inode> Ext2FS::create_inode(InodeIdentifier parent_id, const String& name, mode_t mode, off_t size, dev_t dev, int& error)
{
LOCKER(m_lock);
ASSERT(parent_id.fsid() == fsid());
auto parent_inode = get_inode(parent_id);
dbgprintf("Ext2FS: Adding inode '%s' (mode %o) 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 {};
}
// Try adding it to the directory first, in case the name is already in use.
auto result = parent_inode->add_child({ fsid(), inode_id }, name, mode);
if (result.is_error()) {
error = result;
return {};
}
// 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);
for (auto block_index : blocks) {
success = set_block_allocation_state(block_index, 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;
struct timeval now;
kgettimeofday(now);
ext2_inode e2inode;
memset(&e2inode, 0, sizeof(ext2_inode));
e2inode.i_mode = mode;
e2inode.i_uid = current->process().euid();
e2inode.i_gid = current->process().egid();
e2inode.i_size = size;
e2inode.i_atime = now.tv_sec;
e2inode.i_ctime = now.tv_sec;
e2inode.i_mtime = now.tv_sec;
e2inode.i_dtime = 0;
e2inode.i_links_count = initial_links_count;
if (is_character_device(mode))
e2inode.i_block[0] = dev;
else if (is_block_device(mode))
e2inode.i_block[1] = dev;
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.
m_inode_cache.remove(inode_id);
return get_inode({ fsid(), inode_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;
});
if (!m_lookup_cache.is_empty())
return;
m_lookup_cache = move(children);
}
InodeIdentifier Ext2FSInode::lookup(StringView 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 {};
}
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;
}
int Ext2FSInode::increment_link_count()
{
LOCKER(m_lock);
if (fs().is_readonly())
return -EROFS;
++m_raw_inode.i_links_count;
set_metadata_dirty(true);
return 0;
}
int 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 (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_lock);
m_inode_cache.remove(index);
}
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(off_t size)
{
LOCKER(m_lock);
if ((off_t)m_raw_inode.i_size == size)
return KSuccess;
resize(size);
set_metadata_dirty(true);
return KSuccess;
}
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;
}
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