Method write_to_cache

kernel/kernel/Storage/DiskCache.cpp:77–120

	};

	BAN::ErrorOr<void> DiskCache::write_to_cache(uint64_t sector, BAN::ConstByteSpan buffer, bool dirty)
	{
		ASSERT(buffer.size() >= m_sector_size);

		const uint64_t sectors_per_page = PAGE_SIZE / m_sector_size;
		const uint64_t page_cache_offset = sector % sectors_per_page;
		const uint64_t page_cache_start = sector - page_cache_offset;

		RWLockWRGuard _(m_rw_lock);

		const auto index = find_sector_cache_index(sector);

		if (index >= m_cache.size() || m_cache[index].first_sector != page_cache_start)
		{
			paddr_t paddr = Heap::get().take_free_page();
			if (paddr == 0)
				return BAN::Error::from_errno(ENOMEM);

			PageCache cache {
				.paddr = paddr,
				.first_sector = page_cache_start,
				.sector_mask = 0,
				.dirty_mask = 0,
			};

			if (auto ret = m_cache.insert(index, cache); ret.is_error())
			{
				Heap::get().release_page(paddr);
				return ret.error();
			}
		}

		auto& cache = m_cache[index];

		PageTable::with_per_cpu_fast_page(cache.paddr, [&](void* addr) {
			memcpy(static_cast<uint8_t*>(addr) + page_cache_offset * m_sector_size, buffer.data(), m_sector_size);
		});

		cache.sector_mask |= 1 << page_cache_offset;
		if (dirty)
			cache.dirty_mask |= 1 << page_cache_offset;

		return {};
	}

	BAN::ErrorOr<void> DiskCache::sync_cache_index(size_t index)
	{