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Kernel/FileSystem: Avoid double locking m_inode_lock in the Ext2 driver

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Liav A 2024-02-23 17:18:25 +02:00 • committed by Andrew Kaster
parent b63a1dda63
commit fff49ab6d3
3 changed files with 11 additions and 2 deletions
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5
Kernel/FileSystem/Ext2FS/Inode.cpp
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@ -594,6 +594,7 @@ ErrorOr<size_t> Ext2FSInode::read_bytes_locked(off_t offset, size_t count, UserO
ErrorOr<void> Ext2FSInode::resize(u64 new_size) ErrorOr<void> Ext2FSInode::resize(u64 new_size)
{ {
VERIFY(m_inode_lock.is_locked());
auto old_size = size(); auto old_size = size();
if (old_size == new_size) if (old_size == new_size)
return {}; return {};
@ -655,7 +656,7 @@ ErrorOr<void> Ext2FSInode::resize(u64 new_size)
auto clear_from = old_size; auto clear_from = old_size;
u8 zero_buffer[PAGE_SIZE] {}; u8 zero_buffer[PAGE_SIZE] {};
while (bytes_to_clear) { while (bytes_to_clear) {
auto nwritten = TRY(write_bytes(clear_from, min(static_cast<u64>(sizeof(zero_buffer)), bytes_to_clear), UserOrKernelBuffer::for_kernel_buffer(zero_buffer), nullptr)); auto nwritten = TRY(prepare_and_write_bytes_locked(clear_from, min(static_cast<u64>(sizeof(zero_buffer)), bytes_to_clear), UserOrKernelBuffer::for_kernel_buffer(zero_buffer), nullptr));
VERIFY(nwritten != 0); VERIFY(nwritten != 0);
bytes_to_clear -= nwritten; bytes_to_clear -= nwritten;
clear_from += nwritten; clear_from += nwritten;
@ -816,7 +817,7 @@ ErrorOr<void> Ext2FSInode::write_directory(Vector<Ext2FSDirectoryEntry>& entries
TRY(resize(serialized_bytes_count)); TRY(resize(serialized_bytes_count));
auto buffer = UserOrKernelBuffer::for_kernel_buffer(directory_data.data()); auto buffer = UserOrKernelBuffer::for_kernel_buffer(directory_data.data());
auto nwritten = TRY(write_bytes(0, serialized_bytes_count, buffer, nullptr)); auto nwritten = TRY(prepare_and_write_bytes_locked(0, serialized_bytes_count, buffer, nullptr));
set_metadata_dirty(true); set_metadata_dirty(true);
if (nwritten != directory_data.size()) if (nwritten != directory_data.size())
return EIO; return EIO;

6
Kernel/FileSystem/Inode.cpp
View file

@ -97,6 +97,12 @@ ErrorOr<void> Inode::truncate(u64 size)
ErrorOr<size_t> Inode::write_bytes(off_t offset, size_t length, UserOrKernelBuffer const& target_buffer, OpenFileDescription* open_description) ErrorOr<size_t> Inode::write_bytes(off_t offset, size_t length, UserOrKernelBuffer const& target_buffer, OpenFileDescription* open_description)
{ {
MutexLocker locker(m_inode_lock); MutexLocker locker(m_inode_lock);
return prepare_and_write_bytes_locked(offset, length, target_buffer, open_description);
}
ErrorOr<size_t> Inode::prepare_and_write_bytes_locked(off_t offset, size_t length, UserOrKernelBuffer const& target_buffer, OpenFileDescription* open_description)
{
VERIFY(m_inode_lock.is_locked());
TRY(prepare_to_write_data()); TRY(prepare_to_write_data());
return write_bytes_locked(offset, length, target_buffer, open_description); return write_bytes_locked(offset, length, target_buffer, open_description);
} }

2
Kernel/FileSystem/Inode.h
View file

@ -121,6 +121,8 @@ protected:
mutable Mutex m_inode_lock { "Inode"sv }; mutable Mutex m_inode_lock { "Inode"sv };
ErrorOr<size_t> prepare_and_write_bytes_locked(off_t, size_t, UserOrKernelBuffer const& data, OpenFileDescription*);
virtual ErrorOr<size_t> write_bytes_locked(off_t, size_t, UserOrKernelBuffer const& data, OpenFileDescription*) = 0; virtual ErrorOr<size_t> write_bytes_locked(off_t, size_t, UserOrKernelBuffer const& data, OpenFileDescription*) = 0;
virtual ErrorOr<size_t> read_bytes_locked(off_t, size_t, UserOrKernelBuffer& buffer, OpenFileDescription*) const = 0; virtual ErrorOr<size_t> read_bytes_locked(off_t, size_t, UserOrKernelBuffer& buffer, OpenFileDescription*) const = 0;
virtual ErrorOr<void> truncate_locked(u64) { return {}; } virtual ErrorOr<void> truncate_locked(u64) { return {}; }