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Kernel: Fix TmpFS inode linking 

TmpFS now looks for empty entries in directories instead of always
appending files to the end of directories. This makes kernel not crash
after process pid 126 is created :D
This commit is contained in:
Bananymous 2025-01-28 17:06:35 +02:00
parent efb577769e
commit 7a10e0e347
1 changed files with 72 additions and 25 deletions
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97
kernel/kernel/FS/TmpFS/Inode.cpp
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@ -562,39 +562,86 @@ namespace Kernel
new_entry_size += directory_entry_alignment - rem;
ASSERT(new_entry_size < (size_t)blksize());
size_t new_entry_offset = size() % blksize();
// Target is the last block, or if it doesn't fit the new entry, the next one.
size_t target_data_block = size() / blksize();
if (blksize() - new_entry_offset < new_entry_size)
for (size_t data_block_index = 0; data_block_index * blksize() < (size_t)size(); data_block_index++)
{
// insert an empty entry at the end of current block
m_fs.with_block_buffer(block_index(target_data_block).value(), [&](BAN::ByteSpan bytespan) {
auto& empty_entry = bytespan.slice(new_entry_offset).as<TmpDirectoryEntry>();
empty_entry.type = DT_UNKNOWN;
empty_entry.ino = 0;
empty_entry.rec_len = blksize() - new_entry_offset;
});
m_inode_info.size += blksize() - new_entry_offset;
const size_t block_index = this->block_index(data_block_index).value();
target_data_block++;
new_entry_offset = 0;
bool done = false;
m_fs.with_block_buffer(block_index, [&](BAN::ByteSpan bytespan) {
bytespan = bytespan.slice(0, blksize());
while (bytespan.size() > 0)
{
auto& entry = bytespan.as<TmpDirectoryEntry>();
while (entry.ino == 0 && entry.rec_len < bytespan.size())
{
auto& next_entry = bytespan.slice(entry.rec_len).as<TmpDirectoryEntry>();
if (next_entry.ino)
break;
entry.rec_len += next_entry.rec_len;
}
size_t block_index = TRY(block_index_with_allocation(target_data_block));
if (entry.ino != 0 || entry.rec_len < new_entry_size)
{
bytespan = bytespan.slice(entry.rec_len);
continue;
}
if (entry.rec_len <= new_entry_size + sizeof(TmpDirectoryEntry))
new_entry_size = entry.rec_len;
else
{
auto& new_entry = bytespan.slice(new_entry_size).as<TmpDirectoryEntry>();
new_entry.type = DT_UNKNOWN;
new_entry.ino = 0;
new_entry.rec_len = entry.rec_len - new_entry_size;
}
ASSERT(entry.type == DT_UNKNOWN);
entry.type = inode_mode_to_dt_type(inode.mode());
entry.ino = inode.ino();
entry.name_len = name.size();
entry.rec_len = new_entry_size;
memcpy(entry.name, name.data(), name.size());
done = true;
break;
}
});
if (done)
{
// add link to linked inode
inode.m_inode_info.nlink++;
return {};
}
}
const size_t data_block_index = size() / blksize();
const size_t block_index = TRY(block_index_with_allocation(data_block_index));
m_fs.with_block_buffer(block_index, [&](BAN::ByteSpan bytespan) {
auto& new_entry = bytespan.slice(new_entry_offset).as<TmpDirectoryEntry>();
ASSERT(new_entry.type == DT_UNKNOWN);
new_entry.type = inode_mode_to_dt_type(inode.mode());
new_entry.ino = inode.ino();
new_entry.name_len = name.size();
new_entry.rec_len = new_entry_size;
memcpy(new_entry.name, name.data(), name.size());
// insert new inode
{
auto& entry = bytespan.as<TmpDirectoryEntry>();
entry.type = inode_mode_to_dt_type(inode.mode());
entry.ino = inode.ino();
entry.name_len = name.size();
entry.rec_len = new_entry_size;
memcpy(entry.name, name.data(), name.size());
}
// insert null entry
{
auto& entry = bytespan.slice(new_entry_size).as<TmpDirectoryEntry>();
entry.type = DT_UNKNOWN;
entry.ino = 0;
entry.rec_len = blksize() - new_entry_size;
}
});
// increase current size
m_inode_info.size += new_entry_size;
m_inode_info.size += blksize();
// add link to linked inode
inode.m_inode_info.nlink++;
@ -616,7 +663,7 @@ namespace Kernel
while (bytespan.size() > 0)
{
auto& entry = bytespan.as<TmpDirectoryEntry>();
if (entry.type != DT_UNKNOWN)
if (entry.ino != 0)
{
switch (callback(entry))
{