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ladybird/VirtualFileSystem/Ext2FileSystem.cpp
Andreas Kling bda0c935c2 Add unlink() syscall and /bin/rm. 
This patch adds most of the plumbing for working file deletion in Ext2FS.
Directory entries are removed and inode link counts updated.
We don't yet update the inode or block bitmaps, I will do that separately.
2019-01-22 07:03:44 +01:00

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#include "Ext2FileSystem.h"
#include "ext2_fs.h"
#include "UnixTypes.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_blockGroupCount);
if (!m_cached_group_descriptor_table) {
unsigned blocksToRead = ceilDiv(m_blockGroupCount * (unsigned)sizeof(ext2_group_desc), blockSize());
unsigned firstBlockOfBGDT = blockSize() == 1024 ? 2 : 1;
#ifdef EXT2_DEBUG
kprintf("ext2fs: block group count: %u, blocks-to-read: %u\n", m_blockGroupCount, blocksToRead);
kprintf("ext2fs: first block of BGDT: %u\n", firstBlockOfBGDT);
#endif
m_cached_group_descriptor_table = readBlocks(firstBlockOfBGDT, blocksToRead);
}
return reinterpret_cast<ext2_group_desc*>(m_cached_group_descriptor_table.pointer())[groupIndex - 1];
}
bool Ext2FS::initialize()
{
auto& superBlock = this->super_block();
#ifdef EXT2_DEBUG
kprintf("ext2fs: super block magic: %x (super block size: %u)\n", superBlock.s_magic, sizeof(ext2_super_block));
#endif
if (superBlock.s_magic != EXT2_SUPER_MAGIC)
return false;
#ifdef EXT2_DEBUG
kprintf("ext2fs: %u inodes, %u blocks\n", superBlock.s_inodes_count, superBlock.s_blocks_count);
kprintf("ext2fs: block size = %u\n", EXT2_BLOCK_SIZE(&superBlock));
kprintf("ext2fs: first data block = %u\n", superBlock.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", superBlock.s_free_inodes_count);
kprintf("ext2fs: desc per block = %u\n", EXT2_DESC_PER_BLOCK(&superBlock));
kprintf("ext2fs: desc size = %u\n", EXT2_DESC_SIZE(&superBlock));
#endif
setBlockSize(EXT2_BLOCK_SIZE(&superBlock));
m_blockGroupCount = ceilDiv(superBlock.s_blocks_count, superBlock.s_blocks_per_group);
if (m_blockGroupCount == 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_blockGroupCount; ++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 { id(), EXT2_ROOT_INO };
}
ByteBuffer Ext2FS::read_block_containing_inode(unsigned inode, unsigned& blockIndex, unsigned& offset) const
{
auto& superBlock = this->super_block();
if (inode != EXT2_ROOT_INO && inode < EXT2_FIRST_INO(&superBlock))
return { };
if (inode > superBlock.s_inodes_count)
return { };
auto& bgd = group_descriptor(group_index_from_inode(inode));
offset = ((inode - 1) % inodes_per_group()) * inode_size();
blockIndex = bgd.bg_inode_table + (offset >> EXT2_BLOCK_SIZE_BITS(&superBlock));
offset &= blockSize() - 1;
return readBlock(blockIndex);
}
Vector<unsigned> Ext2FS::block_list_for_inode(const ext2_inode& e2inode) const
{
unsigned entriesPerBlock = EXT2_ADDR_PER_BLOCK(&super_block());
// NOTE: i_blocks is number of 512-byte blocks, not number of fs-blocks.
unsigned blockCount = e2inode.i_blocks / (blockSize() / 512);
unsigned blocksRemaining = blockCount;
Vector<unsigned> list;
list.ensure_capacity(blocksRemaining);
unsigned directCount = min(blockCount, (unsigned)EXT2_NDIR_BLOCKS);
for (unsigned i = 0; i < directCount; ++i) {
list.unchecked_append(e2inode.i_block[i]);
--blocksRemaining;
}
if (!blocksRemaining)
return list;
auto processBlockArray = [&] (unsigned arrayBlockIndex, auto&& callback) {
auto arrayBlock = readBlock(arrayBlockIndex);
ASSERT(arrayBlock);
auto* array = reinterpret_cast<const __u32*>(arrayBlock.pointer());
unsigned count = min(blocksRemaining, entriesPerBlock);
for (unsigned i = 0; i < count; ++i) {
if (!array[i]) {
blocksRemaining = 0;
return;
}
callback(array[i]);
--blocksRemaining;
}
};
processBlockArray(e2inode.i_block[EXT2_IND_BLOCK], [&] (unsigned entry) {
list.unchecked_append(entry);
});
if (!blocksRemaining)
return list;
processBlockArray(e2inode.i_block[EXT2_DIND_BLOCK], [&] (unsigned entry) {
processBlockArray(entry, [&] (unsigned entry) {
list.unchecked_append(entry);
});
});
if (!blocksRemaining)
return list;
processBlockArray(e2inode.i_block[EXT2_TIND_BLOCK], [&] (unsigned entry) {
processBlockArray(entry, [&] (unsigned entry) {
processBlockArray(entry, [&] (unsigned entry) {
list.unchecked_append(entry);
});
});
});
return list;
}
Ext2FSInode::Ext2FSInode(Ext2FS& fs, unsigned index, const ext2_inode& raw_inode)
: Inode(fs, index)
, m_raw_inode(raw_inode)
{
}
Ext2FSInode::~Ext2FSInode()
{
if (m_raw_inode.i_links_count == 0) {
dbgprintf("Ext2FS: inode %u has no more links, time to delete!\n", index());
// FIXME: Implement!
ASSERT_NOT_REACHED();
}
}
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.linkCount = 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.blockSize = fs().blockSize();
metadata.blockCount = m_raw_inode.i_blocks;
if (isBlockDevice(m_raw_inode.i_mode) || isCharacterDevice(m_raw_inode.i_mode)) {
unsigned dev = m_raw_inode.i_block[0];
metadata.majorDevice = (dev & 0xfff00) >> 8;
metadata.minorDevice= (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()) {
// FIXME: This invalidation is way too hardcore.
LOCKER(m_lock);
m_lookup_cache.clear();
}
set_metadata_dirty(false);
}
RetainPtr<Inode> Ext2FS::get_inode(InodeIdentifier inode) const
{
ASSERT(inode.fsid() == id());
{
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 { };
// FIXME: Avoid this extra allocation, copy the raw inode directly into the Ext2FSInode metadata somehow.
auto* e2inode = reinterpret_cast<ext2_inode*>(kmalloc(inode_size()));
memcpy(e2inode, reinterpret_cast<ext2_inode*>(block.offset_pointer(offset)), inode_size());
auto raw_inode = OwnPtr<ext2_inode>(e2inode);
if (!raw_inode)
return nullptr;
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(), *raw_inode));
m_inode_cache.set(inode.index(), new_inode.copyRef());
return new_inode;
}
ssize_t Ext2FSInode::read_bytes(Unix::off_t offset, size_t count, byte* buffer, FileDescriptor*)
{
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((Unix::off_t)size() - offset, static_cast<Unix::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().blockSize();
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((Unix::off_t)count, (Unix::off_t)size() - offset);
byte* out = buffer;
#ifdef EXT2_DEBUG
kprintf("Ext2FS: Reading %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().readBlock(m_block_list[bi]);
if (!block) {
kprintf("ext2fs: read_bytes: readBlock(%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;
}
bool Ext2FSInode::write(const ByteBuffer& data)
{
// FIXME: Support writing to symlink inodes.
ASSERT(!is_symlink());
unsigned blocksNeededBefore = ceilDiv(size(), fs().blockSize());
unsigned blocksNeededAfter = ceilDiv((unsigned)data.size(), fs().blockSize());
// FIXME: Support growing or shrinking the block list.
ASSERT(blocksNeededBefore == blocksNeededAfter);
auto list = fs().block_list_for_inode(m_raw_inode);
if (list.is_empty()) {
kprintf("ext2fs: writeInode: empty block list for inode %u\n", index());
return false;
}
for (unsigned i = 0; i < list.size(); ++i) {
auto section = data.slice(i * fs().blockSize(), fs().blockSize());
//kprintf("section = %p (%u)\n", section.pointer(), section.size());
bool success = fs().writeBlock(list[i], section);
ASSERT(success);
}
return true;
}
bool Ext2FSInode::traverse_as_directory(Function<bool(const FS::DirectoryEntry&)> callback)
{
ASSERT(metadata().isDirectory());
#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, entry->name);
#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)
{
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 directorySize = 0;
for (auto& entry : entries) {
//kprintf(" - %08u %s\n", entry.inode.index(), entry.name);
directorySize += EXT2_DIR_REC_LEN(entry.name_length);
}
unsigned blocksNeeded = ceilDiv(directorySize, blockSize());
unsigned occupiedSize = blocksNeeded * blockSize();
dbgprintf("Ext2FS: directory size: %u (occupied: %u)\n", directorySize, occupiedSize);
auto directoryData = ByteBuffer::create_uninitialized(occupiedSize);
BufferStream stream(directoryData);
for (unsigned i = 0; i < entries.size(); ++i) {
auto& entry = entries[i];
unsigned recordLength = EXT2_DIR_REC_LEN(entry.name_length);
if (i == entries.size() - 1)
recordLength += occupiedSize - directorySize;
dbgprintf("* inode: %u", entry.inode.index());
dbgprintf(", name_len: %u", word(entry.name_length));
dbgprintf(", rec_len: %u", word(recordLength));
dbgprintf(", file_type: %u", byte(entry.fileType));
dbgprintf(", name: %s\n", entry.name);
stream << dword(entry.inode.index());
stream << word(recordLength);
stream << byte(entry.name_length);
stream << byte(entry.fileType);
stream << entry.name;
unsigned padding = recordLength - entry.name_length - 8;
//dbgprintf(" *** pad %u bytes\n", padding);
for (unsigned j = 0; j < padding; ++j) {
stream << byte(0);
}
}
stream.fillToEnd(0);
#if 0
kprintf("data to write (%u):\n", directoryData.size());
for (unsigned i = 0; i < directoryData.size(); ++i) {
kprintf("%02x ", directoryData[i]);
if ((i + 1) % 8 == 0)
kprintf(" ");
if ((i + 1) % 16 == 0)
kprintf("\n");
}
kprintf("\n");
#endif
return get_inode({ id(), directoryInode })->write(directoryData);
}
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_blockGroupCount);
auto& bgd = group_descriptor(groupIndex);
unsigned blocksInGroup = min(blocks_per_group(), super_block().s_blocks_count);
unsigned blockCount = ceilDiv(blocksInGroup, 8u);
auto bitmapBlocks = readBlocks(bgd.bg_block_bitmap, blockCount);
ASSERT(bitmapBlocks);
kprintf("ext2fs: group[%u] block bitmap (bitmap occupies %u blocks):\n", groupIndex, blockCount);
auto bitmap = Bitmap::wrap(bitmapBlocks.pointer(), blocksInGroup);
for (unsigned i = 0; i < blocksInGroup; ++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_blockGroupCount);
auto& bgd = group_descriptor(groupIndex);
unsigned inodesInGroup = min(inodes_per_group(), super_block().s_inodes_count);
unsigned blockCount = ceilDiv(inodesInGroup, 8u);
for (unsigned i = 0; i < blockCount; ++i) {
auto block = readBlock(bgd.bg_inode_bitmap + i);
ASSERT(block);
bool shouldContinue = callback(i * (blockSize() / 8) + 1, Bitmap::wrap(block.pointer(), inodesInGroup));
if (!shouldContinue)
break;
}
}
template<typename F>
void Ext2FS::traverse_block_bitmap(unsigned groupIndex, F callback) const
{
ASSERT(groupIndex <= m_blockGroupCount);
auto& bgd = group_descriptor(groupIndex);
unsigned blocksInGroup = min(blocks_per_group(), super_block().s_blocks_count);
unsigned blockCount = ceilDiv(blocksInGroup, 8u);
for (unsigned i = 0; i < blockCount; ++i) {
auto block = readBlock(bgd.bg_block_bitmap + i);
ASSERT(block);
bool shouldContinue = callback(i * (blockSize() / 8) + 1, Bitmap::wrap(block.pointer(), blocksInGroup));
if (!shouldContinue)
break;
}
}
bool Ext2FS::write_ext2_inode(unsigned inode, const ext2_inode& e2inode)
{
unsigned blockIndex;
unsigned offset;
auto block = read_block_containing_inode(inode, blockIndex, offset);
if (!block)
return false;
memcpy(reinterpret_cast<ext2_inode*>(block.offset_pointer(offset)), &e2inode, inode_size());
writeBlock(blockIndex, 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 preferredGroup, unsigned expectedSize)
{
dbgprintf("Ext2FS: allocate_inode(preferredGroup: %u, expectedSize: %u)\n", preferredGroup, expectedSize);
unsigned neededBlocks = ceilDiv(expectedSize, blockSize());
dbgprintf("Ext2FS: minimum needed blocks: %u\n", neededBlocks);
unsigned groupIndex = 0;
auto isSuitableGroup = [this, neededBlocks] (unsigned groupIndex) {
auto& bgd = group_descriptor(groupIndex);
return bgd.bg_free_inodes_count && bgd.bg_free_blocks_count >= neededBlocks;
};
if (preferredGroup && isSuitableGroup(preferredGroup)) {
groupIndex = preferredGroup;
} else {
for (unsigned i = 1; i <= m_blockGroupCount; ++i) {
if (isSuitableGroup(i))
groupIndex = i;
}
}
if (!groupIndex) {
kprintf("Ext2FS: allocate_inode: no suitable group found for new inode with %u blocks needed :(\n", neededBlocks);
return 0;
}
dbgprintf("Ext2FS: allocate_inode: found suitable group [%u] for new inode with %u blocks needed :^)\n", groupIndex, neededBlocks);
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 = blockSize() * 8;
unsigned bitmap_block_index = (index - 1) / inodes_per_bitmap_block;
unsigned bit_index = (index - 1) % inodes_per_bitmap_block;
auto block = readBlock(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 = blockSize() * 8;
unsigned bitmap_block_index = (index - 1) / inodes_per_bitmap_block;
unsigned bit_index = (index - 1) % inodes_per_bitmap_block;
auto block = readBlock(bgd.bg_inode_bitmap + bitmap_block_index);
ASSERT(block);
auto bitmap = Bitmap::wrap(block.pointer(), block.size());
bool currentState = bitmap.get(bit_index);
dbgprintf("Ext2FS: set_inode_allocation_state(%u) %u -> %u\n", index, currentState, newState);
if (currentState == newState)
return true;
bitmap.set(bit_index, newState);
writeBlock(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& mutableBGD = const_cast<ext2_group_desc&>(bgd);
if (newState)
--mutableBGD.bg_free_inodes_count;
else
++mutableBGD.bg_free_inodes_count;
dbgprintf("Ext2FS: group free inode count %u -> %u\n", bgd.bg_free_inodes_count, bgd.bg_free_inodes_count - 1);
unsigned blocksToWrite = ceilDiv(m_blockGroupCount * (unsigned)sizeof(ext2_group_desc), blockSize());
unsigned firstBlockOfBGDT = blockSize() == 1024 ? 2 : 1;
writeBlocks(firstBlockOfBGDT, blocksToWrite, m_cached_group_descriptor_table);
return true;
}
bool Ext2FS::set_block_allocation_state(GroupIndex group, BlockIndex bi, bool newState)
{
auto& bgd = group_descriptor(group);
// Update block bitmap
unsigned blocksPerBitmapBlock = blockSize() * 8;
unsigned bitmapBlockIndex = (bi - 1) / blocksPerBitmapBlock;
unsigned bitIndex = (bi - 1) % blocksPerBitmapBlock;
auto block = readBlock(bgd.bg_block_bitmap + bitmapBlockIndex);
ASSERT(block);
auto bitmap = Bitmap::wrap(block.pointer(), block.size());
bool currentState = bitmap.get(bitIndex);
dbgprintf("Ext2FS: setBlockAllocationState(%u) %u -> %u\n", bi, currentState, newState);
if (currentState == newState)
return true;
bitmap.set(bitIndex, newState);
writeBlock(bgd.bg_block_bitmap + bitmapBlockIndex, 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 (newState)
--sb.s_free_blocks_count;
else
++sb.s_free_blocks_count;
write_super_block(sb);
// Update BGD
auto& mutableBGD = const_cast<ext2_group_desc&>(bgd);
if (newState)
--mutableBGD.bg_free_blocks_count;
else
++mutableBGD.bg_free_blocks_count;
dbgprintf("Ext2FS: group free block count %u -> %u\n", bgd.bg_free_blocks_count, bgd.bg_free_blocks_count - 1);
unsigned blocksToWrite = ceilDiv(m_blockGroupCount * (unsigned)sizeof(ext2_group_desc), blockSize());
unsigned firstBlockOfBGDT = blockSize() == 1024 ? 2 : 1;
writeBlocks(firstBlockOfBGDT, blocksToWrite, m_cached_group_descriptor_table);
return true;
}
RetainPtr<Inode> Ext2FS::create_directory(InodeIdentifier parent_id, const String& name, Unix::mode_t mode, int& error)
{
ASSERT(parent_id.fsid() == id());
// 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, blockSize(), 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);
unsigned blocksToWrite = ceilDiv(m_blockGroupCount * (unsigned)sizeof(ext2_group_desc), blockSize());
unsigned firstBlockOfBGDT = blockSize() == 1024 ? 2 : 1;
writeBlocks(firstBlockOfBGDT, blocksToWrite, m_cached_group_descriptor_table);
error = 0;
return inode;
}
RetainPtr<Inode> Ext2FS::create_inode(InodeIdentifier parent_id, const String& name, Unix::mode_t mode, unsigned size, int& error)
{
ASSERT(parent_id.fsid() == id());
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, 0);
if (!inode_id) {
kprintf("Ext2FS: create_inode: allocate_inode failed\n");
error = -ENOSPC;
return { };
}
auto needed_blocks = ceilDiv(size, blockSize());
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 fileType = 0;
if (isRegularFile(mode))
fileType = EXT2_FT_REG_FILE;
else if (isDirectory(mode))
fileType = EXT2_FT_DIR;
else if (isCharacterDevice(mode))
fileType = EXT2_FT_CHRDEV;
else if (isBlockDevice(mode))
fileType = EXT2_FT_BLKDEV;
else if (isFIFO(mode))
fileType = EXT2_FT_FIFO;
else if (isSocket(mode))
fileType = EXT2_FT_SOCK;
else if (isSymbolicLink(mode))
fileType = EXT2_FT_SYMLINK;
// Try adding it to the directory first, in case the name is already in use.
bool success = parent_inode->add_child({ id(), inode_id }, name, fileType, 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 initialLinksCount;
if (isDirectory(mode))
initialLinksCount = 2; // (parent directory + "." entry in self)
else
initialLinksCount = 1;
auto timestamp = ktime(nullptr);
auto e2inode = make<ext2_inode>();
memset(e2inode.ptr(), 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 = initialLinksCount;
e2inode->i_blocks = blocks.size() * (blockSize() / 512);
// FIXME: Implement writing out indirect blocks!
ASSERT(blocks.size() < EXT2_NDIR_BLOCKS);
dbgprintf("Ext2FS: writing %u blocks to i_block array\n", min((size_t)EXT2_NDIR_BLOCKS, blocks.size()));
for (unsigned i = 0; i < min((size_t)EXT2_NDIR_BLOCKS, blocks.size()); ++i) {
e2inode->i_block[i] = blocks[i];
}
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({ id(), 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()
{
{
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(Unix::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(Unix::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(Unix::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);
}
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