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ladybird/VirtualFileSystem/Ext2FileSystem.cpp
Andreas Kling 705832f387 List the root directory after mounting /. 
So cool that it works! It's spewing out a bunch of terminal escape sequences
that the OS console obviously doesn't support, but we'll get there too.
2018-10-17 11:47:14 +02:00

979 lines
32 KiB
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#include "Ext2FileSystem.h"
#include "ext2_fs.h"
#include "UnixTypes.h"
#include <AK/Bitmap.h>
#include <AK/StdLib.h>
#include <AK/kmalloc.h>
#include <AK/ktime.h>
#include <AK/kstdio.h>
#include "sys-errno.h"
//#define EXT2_DEBUG
RetainPtr<Ext2FileSystem> Ext2FileSystem::create(RetainPtr<DiskDevice>&& device)
{
return adopt(*new Ext2FileSystem(move(device)));
}
Ext2FileSystem::Ext2FileSystem(RetainPtr<DiskDevice>&& device)
: DiskBackedFileSystem(move(device))
{
}
Ext2FileSystem::~Ext2FileSystem()
{
}
ByteBuffer Ext2FileSystem::readSuperBlock() const
{
auto buffer = ByteBuffer::createUninitialized(1024);
device().readBlock(2, buffer.pointer());
device().readBlock(3, buffer.offsetPointer(512));
return buffer;
}
bool Ext2FileSystem::writeSuperBlock(const ext2_super_block& sb)
{
const byte* raw = (const byte*)&sb;
bool success;
success = device().writeBlock(2, raw);
ASSERT(success);
success = device().writeBlock(3, raw + 512);
ASSERT(success);
// FIXME: This is an ugly way to refresh the superblock cache. :-|
superBlock();
return true;
}
unsigned Ext2FileSystem::firstBlockOfGroup(unsigned groupIndex) const
{
return superBlock().s_first_data_block + (groupIndex * superBlock().s_blocks_per_group);
}
const ext2_super_block& Ext2FileSystem::superBlock() const
{
if (!m_cachedSuperBlock)
m_cachedSuperBlock = readSuperBlock();
return *reinterpret_cast<ext2_super_block*>(m_cachedSuperBlock.pointer());
}
const ext2_group_desc& Ext2FileSystem::blockGroupDescriptor(unsigned groupIndex) const
{
// FIXME: Should this fail gracefully somehow?
ASSERT(groupIndex <= m_blockGroupCount);
if (!m_cachedBlockGroupDescriptorTable) {
unsigned blocksToRead = ceilDiv(m_blockGroupCount * (unsigned)sizeof(ext2_group_desc), blockSize());
kprintf("[ext2fs] block group count: %u, blocks-to-read: %u\n", m_blockGroupCount, blocksToRead);
unsigned firstBlockOfBGDT = blockSize() == 1024 ? 2 : 1;
kprintf("[ext2fs] first block of BGDT: %u\n", firstBlockOfBGDT);
m_cachedBlockGroupDescriptorTable = readBlocks(firstBlockOfBGDT, blocksToRead);
}
return reinterpret_cast<ext2_group_desc*>(m_cachedBlockGroupDescriptorTable.pointer())[groupIndex - 1];
}
bool Ext2FileSystem::initialize()
{
auto& superBlock = this->superBlock();
kprintf("[ext2fs] super block magic: %x (super block size: %u)\n", superBlock.s_magic, sizeof(ext2_super_block));
if (superBlock.s_magic != EXT2_SUPER_MAGIC)
return false;
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", inodesPerBlock());
kprintf("[ext2fs] inodes per group = %u\n", inodesPerGroup());
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));
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;
}
for (unsigned i = 1; i <= m_blockGroupCount; ++i) {
auto& group = blockGroupDescriptor(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);
}
return true;
}
const char* Ext2FileSystem::className() const
{
return "ext2fs";
}
InodeIdentifier Ext2FileSystem::rootInode() const
{
return { id(), EXT2_ROOT_INO };
}
#ifdef EXT2_DEBUG
static void dumpExt2Inode(const ext2_inode& inode)
{
kprintf("Dump of ext2_inode:\n");
kprintf(" i_size: %u\n", inode.i_size);
kprintf(" i_mode: %u\n", inode.i_mode);
kprintf(" i_blocks: %u\n", inode.i_blocks);
kprintf(" i_uid: %u\n", inode.i_uid);
kprintf(" i_gid: %u\n", inode.i_gid);
}
#endif
ByteBuffer Ext2FileSystem::readBlockContainingInode(unsigned inode, unsigned& blockIndex, unsigned& offset) const
{
auto& superBlock = this->superBlock();
if (inode != EXT2_ROOT_INO && inode < EXT2_FIRST_INO(&superBlock))
return { };
if (inode > superBlock.s_inodes_count)
return { };
auto& bgd = blockGroupDescriptor(groupIndexFromInode(inode));
offset = ((inode - 1) % inodesPerGroup()) * inodeSize();
blockIndex = bgd.bg_inode_table + (offset >> EXT2_BLOCK_SIZE_BITS(&superBlock));
offset &= blockSize() - 1;
return readBlock(blockIndex);
}
OwnPtr<ext2_inode> Ext2FileSystem::lookupExt2Inode(unsigned inode) const
{
unsigned blockIndex;
unsigned offset;
auto block = readBlockContainingInode(inode, blockIndex, offset);
if (!block)
return nullptr;
auto* e2inode = reinterpret_cast<ext2_inode*>(kmalloc(inodeSize()));
memcpy(e2inode, reinterpret_cast<ext2_inode*>(block.offsetPointer(offset)), inodeSize());
#ifdef EXT2_DEBUG
dumpExt2Inode(*e2inode);
#endif
return OwnPtr<ext2_inode>(e2inode);
}
InodeMetadata Ext2FileSystem::inodeMetadata(InodeIdentifier inode) const
{
ASSERT(inode.fileSystemID() == id());
auto e2inode = lookupExt2Inode(inode.index());
if (!e2inode)
return InodeMetadata();
InodeMetadata metadata;
metadata.inode = inode;
metadata.size = e2inode->i_size;
metadata.mode = e2inode->i_mode;
metadata.uid = e2inode->i_uid;
metadata.gid = e2inode->i_gid;
metadata.linkCount = e2inode->i_links_count;
metadata.atime = e2inode->i_atime;
metadata.ctime = e2inode->i_ctime;
metadata.mtime = e2inode->i_mtime;
metadata.dtime = e2inode->i_dtime;
metadata.blockSize = blockSize();
metadata.blockCount = e2inode->i_blocks;
if (isBlockDevice(e2inode->i_mode) || isCharacterDevice(e2inode->i_mode)) {
unsigned dev = e2inode->i_block[0];
metadata.majorDevice = (dev & 0xfff00) >> 8;
metadata.minorDevice= (dev & 0xff) | ((dev >> 12) & 0xfff00);
}
return metadata;
}
Vector<unsigned> Ext2FileSystem::blockListForInode(const ext2_inode& e2inode) const
{
unsigned entriesPerBlock = EXT2_ADDR_PER_BLOCK(&superBlock());
// 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.ensureCapacity(blocksRemaining);
unsigned directCount = min(blockCount, (unsigned)EXT2_NDIR_BLOCKS);
for (unsigned i = 0; i < directCount; ++i) {
list.append(e2inode.i_block[i]);
--blocksRemaining;
}
if (!blocksRemaining)
return list;
auto processBlockArray = [&] (unsigned arrayBlockIndex, Function<void(unsigned)> 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.append(entry);
});
if (!blocksRemaining)
return list;
processBlockArray(e2inode.i_block[EXT2_DIND_BLOCK], [&] (unsigned entry) {
processBlockArray(entry, [&] (unsigned entry) {
list.append(entry);
});
});
if (!blocksRemaining)
return list;
processBlockArray(e2inode.i_block[EXT2_TIND_BLOCK], [&] (unsigned entry) {
processBlockArray(entry, [&] (unsigned entry) {
processBlockArray(entry, [&] (unsigned entry) {
list.append(entry);
});
});
});
return list;
}
Unix::ssize_t Ext2FileSystem::readInodeBytes(InodeIdentifier inode, Unix::off_t offset, Unix::size_t count, byte* buffer) const
{
ASSERT(offset >= 0);
ASSERT(inode.fileSystemID() == id());
auto e2inode = lookupExt2Inode(inode.index());
if (!e2inode) {
kprintf("[ext2fs] readInodeBytes: metadata lookup for inode %u failed\n", inode.index());
return -EIO;
}
#if 0
// FIXME: We can't fail here while the directory traversal depends on this function. :]
if (isDirectory(e2inode->i_mode))
return -EISDIR;
#endif
if (e2inode->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 maxInlineSymlinkLength = 60;
if (isSymbolicLink(e2inode->i_mode) && e2inode->i_size < maxInlineSymlinkLength) {
Unix::ssize_t nread = min((Unix::off_t)e2inode->i_size - offset, static_cast<Unix::off_t>(count));
memcpy(buffer, e2inode->i_block + offset, nread);
return nread;
}
// FIXME: It's grossly inefficient to fetch the blocklist on every call to readInodeBytes().
// It needs to be cached!
auto list = blockListForInode(*e2inode);
if (list.isEmpty()) {
kprintf("[ext2fs] readInodeBytes: empty block list for inode %u\n", inode.index());
return -EIO;
}
dword firstBlockLogicalIndex = offset / blockSize();
dword lastBlockLogicalIndex = (offset + count) / blockSize();
if (lastBlockLogicalIndex >= list.size())
lastBlockLogicalIndex = list.size() - 1;
dword offsetIntoFirstBlock = offset % blockSize();
Unix::ssize_t nread = 0;
Unix::size_t remainingCount = min((Unix::off_t)count, (Unix::off_t)e2inode->i_size - offset);
byte* out = buffer;
#ifdef EXT2_DEBUG
kprintf("ok let's do it, read(%llu, %u) -> blocks %u thru %u, oifb: %u\n", offset, count, firstBlockLogicalIndex, lastBlockLogicalIndex, offsetIntoFirstBlock);
#endif
for (dword bi = firstBlockLogicalIndex; bi <= lastBlockLogicalIndex; ++bi) {
auto block = readBlock(list[bi]);
if (!block) {
kprintf("[ext2fs] readInodeBytes: readBlock(%u) failed (lbi: %u)\n", list[bi], bi);
return -EIO;
}
dword offsetIntoBlock;
if (bi == firstBlockLogicalIndex)
offsetIntoBlock = offsetIntoFirstBlock;
else
offsetIntoBlock = 0;
dword numBytesToCopy = min(blockSize() - offsetIntoBlock, remainingCount);
memcpy(out, block.pointer() + offsetIntoBlock, numBytesToCopy);
remainingCount -= numBytesToCopy;
nread += numBytesToCopy;
out += numBytesToCopy;
}
return nread;
}
bool Ext2FileSystem::writeInode(InodeIdentifier inode, const ByteBuffer& data)
{
ASSERT(inode.fileSystemID() == id());
auto e2inode = lookupExt2Inode(inode.index());
if (!e2inode) {
kprintf("[ext2fs] writeInode: metadata lookup for inode %u failed\n", inode.index());
return false;
}
// FIXME: Support writing to symlink inodes.
ASSERT(!isSymbolicLink(e2inode->i_mode));
unsigned blocksNeededBefore = ceilDiv(e2inode->i_size, blockSize());
unsigned blocksNeededAfter = ceilDiv((unsigned)data.size(), blockSize());
// FIXME: Support growing or shrinking the block list.
ASSERT(blocksNeededBefore == blocksNeededAfter);
auto list = blockListForInode(*e2inode);
if (list.isEmpty()) {
kprintf("[ext2fs] writeInode: empty block list for inode %u\n", inode.index());
return false;
}
for (unsigned i = 0; i < list.size(); ++i) {
auto section = data.slice(i * blockSize(), blockSize());
kprintf("section = %p (%u)\n", section.pointer(), section.size());
bool success = writeBlock(list[i], section);
ASSERT(success);
}
return true;
}
bool Ext2FileSystem::enumerateDirectoryInode(InodeIdentifier inode, Function<bool(const DirectoryEntry&)> callback) const
{
ASSERT(inode.fileSystemID() == id());
ASSERT(isDirectoryInode(inode.index()));
#ifdef EXT2_DEBUG
kprintf("[ext2fs] Enumerating directory contents of inode %u:\n", inode.index());
#endif
auto buffer = readEntireInode(inode);
ASSERT(buffer);
auto* entry = reinterpret_cast<ext2_dir_entry_2*>(buffer.pointer());
char namebuf[EXT2_NAME_LEN + 1];
while (entry < buffer.endPointer()) {
if (entry->inode != 0) {
memcpy(namebuf, entry->name, entry->name_len);
namebuf[entry->name_len] = 0;
#ifdef EXT2_DEBUG
kprintf("inode: %u, name_len: %u, rec_len: %u, file_type: %u, name: %s\n", entry->inode, entry->name_len, entry->rec_len, entry->file_type, namebuf);
#endif
if (!callback({ namebuf, { id(), entry->inode }, entry->file_type }))
break;
}
entry = (ext2_dir_entry_2*)((char*)entry + entry->rec_len);
}
return true;
}
bool Ext2FileSystem::addInodeToDirectory(unsigned directoryInode, unsigned inode, const String& name, byte fileType)
{
auto e2inodeForDirectory = lookupExt2Inode(directoryInode);
ASSERT(e2inodeForDirectory);
ASSERT(isDirectory(e2inodeForDirectory->i_mode));
//#ifdef EXT2_DEBUG
kprintf("[ext2fs] Adding inode %u with name '%s' to directory %u\n", inode, name.characters(), directoryInode);
//#endif
Vector<DirectoryEntry> entries;
bool nameAlreadyExists = false;
enumerateDirectoryInode({ id(), directoryInode }, [&] (const DirectoryEntry& entry) {
if (entry.name == name) {
nameAlreadyExists = true;
return false;
}
entries.append(entry);
return true;
});
if (nameAlreadyExists) {
kprintf("[ext2fs] Name '%s' already exists in directory inode %u\n", name.characters(), directoryInode);
return false;
}
entries.append({ name, { id(), inode }, fileType });
return writeDirectoryInode(directoryInode, move(entries));
}
class BufferStream {
public:
explicit BufferStream(ByteBuffer& buffer)
: m_buffer(buffer)
{
}
void operator<<(byte value)
{
m_buffer[m_offset++] = value & 0xffu;
}
void operator<<(word value)
{
m_buffer[m_offset++] = value & 0xffu;
m_buffer[m_offset++] = (byte)(value >> 8) & 0xffu;
}
void operator<<(dword value)
{
m_buffer[m_offset++] = value & 0xffu;
m_buffer[m_offset++] = (byte)(value >> 8) & 0xffu;
m_buffer[m_offset++] = (byte)(value >> 16) & 0xffu;
m_buffer[m_offset++] = (byte)(value >> 24) & 0xffu;
}
void operator<<(const String& value)
{
for (unsigned i = 0; i < value.length(); ++i)
m_buffer[m_offset++] = value[i];
}
void fillToEnd(byte ch)
{
while (m_offset < m_buffer.size())
m_buffer[m_offset++] = ch;
}
private:
ByteBuffer& m_buffer;
Unix::size_t m_offset { 0 };
};
bool Ext2FileSystem::writeDirectoryInode(unsigned directoryInode, Vector<DirectoryEntry>&& entries)
{
kprintf("[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.characters());
directorySize += EXT2_DIR_REC_LEN(entry.name.length());
}
unsigned blocksNeeded = ceilDiv(directorySize, blockSize());
unsigned occupiedSize = blocksNeeded * blockSize();
kprintf("[ext2fs] directory size: %u (occupied: %u)\n", directorySize, occupiedSize);
auto directoryData = ByteBuffer::createUninitialized(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;
kprintf("* inode: %u", entry.inode.index());
kprintf(", name_len: %u", word(entry.name.length()));
kprintf(", rec_len: %u", word(recordLength));
kprintf(", file_type: %u", byte(entry.fileType));
kprintf(", name: %s\n", entry.name.characters());
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;
kprintf(" *** 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
writeInode({ id(), directoryInode }, directoryData);
return true;
}
unsigned Ext2FileSystem::inodesPerBlock() const
{
return EXT2_INODES_PER_BLOCK(&superBlock());
}
unsigned Ext2FileSystem::inodesPerGroup() const
{
return EXT2_INODES_PER_GROUP(&superBlock());
}
unsigned Ext2FileSystem::inodeSize() const
{
return EXT2_INODE_SIZE(&superBlock());
}
unsigned Ext2FileSystem::blocksPerGroup() const
{
return EXT2_BLOCKS_PER_GROUP(&superBlock());
}
void Ext2FileSystem::dumpBlockBitmap(unsigned groupIndex) const
{
ASSERT(groupIndex <= m_blockGroupCount);
auto& bgd = blockGroupDescriptor(groupIndex);
unsigned blocksInGroup = min(blocksPerGroup(), superBlock().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 Ext2FileSystem::dumpInodeBitmap(unsigned groupIndex) const
{
traverseInodeBitmap(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 Ext2FileSystem::traverseInodeBitmap(unsigned groupIndex, F callback) const
{
ASSERT(groupIndex <= m_blockGroupCount);
auto& bgd = blockGroupDescriptor(groupIndex);
unsigned inodesInGroup = min(inodesPerGroup(), superBlock().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 Ext2FileSystem::traverseBlockBitmap(unsigned groupIndex, F callback) const
{
ASSERT(groupIndex <= m_blockGroupCount);
auto& bgd = blockGroupDescriptor(groupIndex);
unsigned blocksInGroup = min(blocksPerGroup(), superBlock().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 Ext2FileSystem::modifyLinkCount(InodeIndex inode, int delta)
{
ASSERT(inode);
auto e2inode = lookupExt2Inode(inode);
if (!e2inode)
return false;
auto newLinkCount = e2inode->i_links_count + delta;
kprintf("changing inode %u link count from %u to %u\n", inode, e2inode->i_links_count, newLinkCount);
e2inode->i_links_count = newLinkCount;
return writeExt2Inode(inode, *e2inode);
}
bool Ext2FileSystem::setModificationTime(InodeIdentifier inode, dword timestamp)
{
ASSERT(inode.fileSystemID() == id());
auto e2inode = lookupExt2Inode(inode.index());
if (!e2inode)
return false;
kprintf("changing inode %u mtime from %u to %u\n", inode.index(), e2inode->i_mtime, timestamp);
e2inode->i_mtime = timestamp;
return writeExt2Inode(inode.index(), *e2inode);
}
bool Ext2FileSystem::writeExt2Inode(unsigned inode, const ext2_inode& e2inode)
{
unsigned blockIndex;
unsigned offset;
auto block = readBlockContainingInode(inode, blockIndex, offset);
if (!block)
return false;
memcpy(reinterpret_cast<ext2_inode*>(block.offsetPointer(offset)), &e2inode, inodeSize());
writeBlock(blockIndex, block);
return true;
}
bool Ext2FileSystem::isDirectoryInode(unsigned inode) const
{
if (auto e2inode = lookupExt2Inode(inode))
return isDirectory(e2inode->i_mode);
return false;
}
Vector<Ext2FileSystem::BlockIndex> Ext2FileSystem::allocateBlocks(unsigned group, unsigned count)
{
kprintf("[ext2fs] allocateBlocks(group: %u, count: %u)\n", group, count);
auto& bgd = blockGroupDescriptor(group);
if (bgd.bg_free_blocks_count < count) {
kprintf("[ext2fs] allocateBlocks 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;
traverseBlockBitmap(group, [&blocks, count] (unsigned firstBlockInBitmap, const Bitmap& bitmap) {
for (unsigned i = 0; i < bitmap.size(); ++i) {
if (!bitmap.get(i)) {
blocks.append(firstBlockInBitmap + i);
if (blocks.size() == count)
return false;
}
}
return true;
});
kprintf("[ext2fs] allocateBlock found these blocks:\n");
for (auto& bi : blocks) {
kprintf(" > %u\n", bi);
}
return blocks;
}
unsigned Ext2FileSystem::allocateInode(unsigned preferredGroup, unsigned expectedSize)
{
kprintf("[ext2fs] allocateInode(preferredGroup: %u, expectedSize: %u)\n", preferredGroup, expectedSize);
unsigned neededBlocks = ceilDiv(expectedSize, blockSize());
kprintf("[ext2fs] minimum needed blocks: %u\n", neededBlocks);
unsigned groupIndex = 0;
auto isSuitableGroup = [this, neededBlocks] (unsigned groupIndex) {
auto& bgd = blockGroupDescriptor(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] allocateInode: no suitable group found for new inode with %u blocks needed :(\n", neededBlocks);
return 0;
}
kprintf("[ext2fs] allocateInode: found suitable group [%u] for new inode with %u blocks needed :^)\n", groupIndex, neededBlocks);
unsigned firstFreeInodeInGroup = 0;
traverseInodeBitmap(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] firstFreeInodeInGroup returned no inode, despite bgd claiming there are inodes :(\n");
return 0;
}
unsigned inode = firstFreeInodeInGroup;
kprintf("[ext2fs] found suitable inode %u\n", inode);
// FIXME: allocate blocks if needed!
return inode;
}
unsigned Ext2FileSystem::groupIndexFromInode(unsigned inode) const
{
if (!inode)
return 0;
return (inode - 1) / inodesPerGroup() + 1;
}
bool Ext2FileSystem::setInodeAllocationState(unsigned inode, bool newState)
{
auto& bgd = blockGroupDescriptor(groupIndexFromInode(inode));
// Update inode bitmap
unsigned inodesPerBitmapBlock = blockSize() * 8;
unsigned bitmapBlockIndex = (inode - 1) / inodesPerBitmapBlock;
unsigned bitIndex = (inode - 1) % inodesPerBitmapBlock;
auto block = readBlock(bgd.bg_inode_bitmap + bitmapBlockIndex);
ASSERT(block);
auto bitmap = Bitmap::wrap(block.pointer(), block.size());
bool currentState = bitmap.get(bitIndex);
kprintf("[ext2fs] setInodeAllocationState(%u) %u -> %u\n", inode, currentState, newState);
if (currentState == newState)
return true;
bitmap.set(bitIndex, newState);
writeBlock(bgd.bg_inode_bitmap + bitmapBlockIndex, block);
// Update superblock
auto& sb = *reinterpret_cast<ext2_super_block*>(m_cachedSuperBlock.pointer());
kprintf("[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;
writeSuperBlock(sb);
// Update BGD
auto& mutableBGD = const_cast<ext2_group_desc&>(bgd);
if (newState)
--mutableBGD.bg_free_inodes_count;
else
++mutableBGD.bg_free_inodes_count;
kprintf("[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_cachedBlockGroupDescriptorTable);
return true;
}
bool Ext2FileSystem::setBlockAllocationState(GroupIndex group, BlockIndex bi, bool newState)
{
auto& bgd = blockGroupDescriptor(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);
kprintf("[ext2fs] setBlockAllocationState(%u) %u -> %u\n", block, 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_cachedSuperBlock.pointer());
kprintf("[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;
writeSuperBlock(sb);
// Update BGD
auto& mutableBGD = const_cast<ext2_group_desc&>(bgd);
if (newState)
--mutableBGD.bg_free_blocks_count;
else
++mutableBGD.bg_free_blocks_count;
kprintf("[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_cachedBlockGroupDescriptorTable);
return true;
}
InodeIdentifier Ext2FileSystem::makeDirectory(InodeIdentifier parentInode, const String& name, Unix::mode_t mode)
{
ASSERT(parentInode.fileSystemID() == id());
ASSERT(isDirectoryInode(parentInode.index()));
// 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 = createInode(parentInode, name, mode, blockSize());
if (!inode.isValid())
return { };
kprintf("[ext2fs] makeDirectory: created new directory named '%s' with inode %u\n", name.characters(), inode.index());
Vector<DirectoryEntry> entries;
entries.append({ ".", inode, EXT2_FT_DIR });
entries.append({ "..", parentInode, EXT2_FT_DIR });
bool success = writeDirectoryInode(inode.index(), move(entries));
ASSERT(success);
success = modifyLinkCount(parentInode.index(), 1);
ASSERT(success);
auto& bgd = const_cast<ext2_group_desc&>(blockGroupDescriptor(groupIndexFromInode(inode.index())));
++bgd.bg_used_dirs_count;
kprintf("[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_cachedBlockGroupDescriptorTable);
return inode;
}
InodeIdentifier Ext2FileSystem::createInode(InodeIdentifier parentInode, const String& name, Unix::mode_t mode, unsigned size)
{
ASSERT(parentInode.fileSystemID() == id());
ASSERT(isDirectoryInode(parentInode.index()));
//#ifdef EXT2_DEBUG
kprintf("[ext2fs] Adding inode '%s' (mode %o) to parent directory %u:\n", name.characters(), mode, parentInode.index());
//#endif
// NOTE: This doesn't commit the inode allocation just yet!
auto inode = allocateInode(0, 0);
if (!inode) {
kprintf("[ext2fs] createInode: allocateInode failed\n");
return { };
}
auto blocks = allocateBlocks(groupIndexFromInode(inode), ceilDiv(size, blockSize()));
if (blocks.isEmpty()) {
kprintf("[ext2fs] createInode: allocateBlocks failed\n");
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 = addInodeToDirectory(parentInode.index(), inode, name, fileType);
if (!success) {
kprintf("[ext2fs] failed to add inode to directory :(\n");
return { };
}
// Looks like we're good, time to update the inode bitmap and group+global inode counters.
success = setInodeAllocationState(inode, true);
ASSERT(success);
for (auto bi : blocks) {
success = setBlockAllocationState(groupIndexFromInode(inode), 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);
kprintf("[XXX] writing %zu 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];
}
e2inode->i_flags = 0;
success = writeExt2Inode(inode, *e2inode);
ASSERT(success);
return { id(), inode };
}
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