Kernel: Don't crash if Ext2 filesystem doing too many fileops

I had a hardlimit of 10 block buffers and if they ran out, the kernel
would crash. this patchs increases the number of buffers to 16 and
removes the crash condition when they run out :D

kernel/include/kernel/FS/Ext2/FileSystem.h

@@ -26,18 +26,40 @@ namespace Kernel
 		class BlockBufferWrapper
 		{
 			BAN_NON_COPYABLE(BlockBufferWrapper);
-			BAN_NON_MOVABLE(BlockBufferWrapper);
 
 		public:
-			BlockBufferWrapper(BAN::Span<uint8_t> buffer, bool& used)
+			BlockBufferWrapper(BAN::Span<uint8_t> buffer, bool* used, Mutex* mutex, ThreadBlocker* blocker)
 				: m_buffer(buffer)
 				, m_used(used)
+				, m_mutex(mutex)
+				, m_blocker(blocker)
 			{
-				ASSERT(m_used);
+				ASSERT(m_used && *m_used);
 			}
+			BlockBufferWrapper(BlockBufferWrapper&& other) { *this = BAN::move(other); }
 			~BlockBufferWrapper()
 			{
-				m_used = false;
+				if (m_used == nullptr)
+					return;
+				m_mutex->lock();
+				*m_used = false;
+				m_blocker->unblock();
+				m_mutex->unlock();
+			}
+
+			BlockBufferWrapper& operator=(BlockBufferWrapper&& other)
+			{
+				this->m_buffer = other.m_buffer;
+				this->m_used = other.m_used;
+				this->m_mutex = other.m_mutex;
+				this->m_blocker = other.m_blocker;
+
+				other.m_buffer = {};
+				other.m_used = nullptr;
+				other.m_mutex = nullptr;
+				other.m_blocker = nullptr;
+
+				return *this;
 			}
 
 			size_t size() const { return m_buffer.size(); }
@@ -53,7 +75,9 @@ namespace Kernel
 
 		private:
 			BAN::Span<uint8_t> m_buffer;
-			bool& m_used;
+			bool* m_used;
+			Mutex* m_mutex;
+			ThreadBlocker* m_blocker;
 		};
 
 	public:
@@ -79,7 +103,7 @@ namespace Kernel
 		BAN::ErrorOr<void> sync_superblock();
 		BAN::ErrorOr<void> sync_block(uint32_t block);
 
-		BlockBufferWrapper get_block_buffer();
+		BAN::ErrorOr<BlockBufferWrapper> get_block_buffer();
 
 		BAN::ErrorOr<uint32_t> reserve_free_block(uint32_t primary_bgd);
 		BAN::ErrorOr<void> release_block(uint32_t block);
@@ -102,7 +126,7 @@ namespace Kernel
 		{
 		public:
 			BlockBufferManager() = default;
-			BlockBufferWrapper get_buffer();
+			BAN::ErrorOr<BlockBufferWrapper> get_buffer();
 
 			BAN::ErrorOr<void> initialize(size_t block_size);
 
@@ -114,7 +138,9 @@ namespace Kernel
 			};
 
 		private:
-			BAN::Array<BlockBuffer, 10> m_buffers;
+			Mutex m_buffer_mutex;
+			ThreadBlocker m_buffer_blocker;
+			BAN::Array<BlockBuffer, 16> m_buffers;
 		};
 
 	private: