Kernel: Fix Ext2 bug for big files

My ext2 implementation was reading wrong blocks for very big block
indices.

kernel/include/kernel/Terminal/TTY.h

@@ -41,7 +41,6 @@ namespace Kernel
 
 		virtual uint32_t height() const = 0;
 		virtual uint32_t width() const = 0;
-		void putchar(uint8_t ch);
 
 		virtual dev_t rdev() const final override { return m_rdev; }
 
@@ -60,10 +59,13 @@ namespace Kernel
 		TTY(mode_t mode, uid_t uid, gid_t gid);
 
 		virtual void putchar_impl(uint8_t ch) = 0;
+		virtual void update_cursor() {}
+
 		virtual BAN::ErrorOr<size_t> read_impl(off_t, BAN::ByteSpan) override;
 		virtual BAN::ErrorOr<size_t> write_impl(off_t, BAN::ConstByteSpan) override;
 
 	private:
+		void putchar(uint8_t ch);
 		void do_backspace();
 
 	protected:

kernel/include/kernel/Terminal/VirtualTTY.h

@@ -24,6 +24,7 @@ namespace Kernel
 	protected:
 		virtual BAN::StringView name() const override { return m_name; }
 		virtual void putchar_impl(uint8_t ch) override;
+		void update_cursor() override;
 
 	private:
 		VirtualTTY(BAN::RefPtr<TerminalDriver>);
@@ -78,6 +79,7 @@ namespace Kernel
 		uint32_t m_saved_row { 0 };
 		uint32_t m_saved_column { 0 };
 
+		bool m_cursor_shown { true };
 		uint32_t m_row { 0 };
 		uint32_t m_column { 0 };
 		Cell* m_buffer { nullptr };

kernel/kernel/FS/Ext2/Inode.cpp

@@ -64,7 +64,9 @@ namespace Kernel
 
 		const uint32_t indices_per_block = blksize() / sizeof(uint32_t);
 
-		const uint32_t divisor = (depth > 1) ? indices_per_block * (depth - 1) : 1;
+		uint32_t divisor = 1;
+		for (uint32_t i = 1; i < depth; i++)
+			divisor *= indices_per_block;
 
 		const uint32_t next_block = block_buffer.span().as_span<uint32_t>()[(index / divisor) % indices_per_block];
 		if (next_block == 0)

kernel/kernel/Terminal/FramebufferTerminal.cpp

@@ -19,6 +19,8 @@ namespace Kernel
 	{
 		const uint8_t* glyph = m_font.has_glyph(ch) ? m_font.glyph(ch) : m_font.glyph('?');
 
+		const bool update_cursor = m_cursor_shown && x == m_cursor_x && y == m_cursor_y;
+
 		x *= m_font.width();
 		y *= m_font.height();
 
@@ -34,17 +36,18 @@ namespace Kernel
 
 		m_framebuffer_device->sync_pixels_rectangle(x, y, m_font.width(), m_font.height());
 
-		if (x == m_cursor_x && y == m_cursor_y)
+		if (update_cursor)
-		{
-			read_cursor();
 			show_cursor(false);
 	}
-	}
 
 	bool FramebufferTerminalDriver::scroll(Color color)
 	{
+		if (m_cursor_shown)
+			show_cursor(true);
 		m_framebuffer_device->scroll(m_font.height(), color.rgb);
 		m_framebuffer_device->sync_pixels_full();
+		if (m_cursor_shown)
+			show_cursor(false);
 		return true;
 	}
 
@@ -62,25 +65,21 @@ namespace Kernel
 	void FramebufferTerminalDriver::read_cursor()
 	{
 		const uint32_t cursor_h = m_font.height() / 8;
+		const uint32_t cursor_w = m_font.width();
 		const uint32_t cursor_top = m_font.height() * 13 / 16;
 
 		const uint32_t x = m_cursor_x * m_font.width();
 		const uint32_t y = m_cursor_y * m_font.height();
 
 		for (uint32_t dy = 0; dy < cursor_h; dy++)
-			for (uint32_t dx = 0; dx < m_font.width(); dx++)
+			for (uint32_t dx = 0; dx < cursor_w; dx++)
-				m_cursor_data[dy * m_font.width() + dx] = m_framebuffer_device->get_pixel(x + dx, y + cursor_top + dy);
+				m_cursor_data[dy * cursor_w + dx] = m_framebuffer_device->get_pixel(x + dx, y + cursor_top + dy);
 	}
 
 	void FramebufferTerminalDriver::show_cursor(bool use_data)
-	{
-		const auto get_color =
-			[this, use_data](uint32_t x, uint32_t y) -> uint32_t
 	{
 		if (!use_data)
-					return m_cursor_color.rgb;
+			read_cursor();
-				return m_cursor_data[y * m_font.width() + x];
-			};
 
 		const uint32_t cursor_h = m_font.height() / 8;
 		const uint32_t cursor_w = m_font.width();
@@ -89,6 +88,14 @@ namespace Kernel
 		const uint32_t x = m_cursor_x * m_font.width();
 		const uint32_t y = m_cursor_y * m_font.height();
 
+		const auto get_color =
+			[&](uint32_t x, uint32_t y) -> uint32_t
+			{
+				if (!use_data)
+					return m_cursor_color.rgb;
+				return m_cursor_data[y * cursor_w + x];
+			};
+
 		for (uint32_t dy = 0; dy < cursor_h; dy++)
 			for (uint32_t dx = 0; dx < cursor_w; dx++)
 				m_framebuffer_device->set_pixel(x + dx, y + cursor_top + dy, get_color(dx, dy));
@@ -100,20 +107,14 @@ namespace Kernel
 		if (m_cursor_shown == shown)
 			return;
 		m_cursor_shown = shown;
-
+		show_cursor(!m_cursor_shown);
-		if (m_cursor_shown)
-		{
-			read_cursor();
-			show_cursor(false);
-		}
-		else
-		{
-			show_cursor(true);
-		}
 	}
 
 	void FramebufferTerminalDriver::set_cursor_position(uint32_t x, uint32_t y)
 	{
+		if (x == m_cursor_x && y == m_cursor_y)
+			return;
+
 		if (!m_cursor_shown)
 		{
 			m_cursor_x = x;
@@ -124,7 +125,6 @@ namespace Kernel
 		show_cursor(true);
 		m_cursor_x = x;
 		m_cursor_y = y;
-		read_cursor();
 		show_cursor(false);
 	}
 

kernel/kernel/Terminal/TTY.cpp

@@ -215,6 +215,7 @@ namespace Kernel
 			auto* ptr = reinterpret_cast<const uint8_t*>(ansi_c_str);
 			while (*ptr)
 				handle_input_byte(*ptr++);
+			update_cursor();
 		}
 	}
 
@@ -358,6 +359,7 @@ namespace Kernel
 		SpinLockGuard _(m_write_lock);
 		for (size_t i = 0; i < buffer.size(); i++)
 			putchar(buffer[i]);
+		update_cursor();
 		return buffer.size();
 	}
 
@@ -366,6 +368,7 @@ namespace Kernel
 		ASSERT(s_tty);
 		SpinLockGuard _(s_tty->m_write_lock);
 		s_tty->putchar(ch);
+		s_tty->update_cursor();
 	}
 
 	bool TTY::is_initialized()

kernel/kernel/Terminal/VirtualTTY.cpp

@@ -357,7 +357,7 @@ namespace Kernel
 			case 'l':
 				if (m_ansi_state.question && m_ansi_state.nums[0] == 25)
 				{
-					m_terminal_driver->set_cursor_shown(ch == 'h');
+					m_cursor_shown = (ch == 'h');
 					return reset_ansi();
 				}
 				reset_ansi();
@@ -518,8 +518,21 @@ namespace Kernel
 		}
 
 		putcodepoint(codepoint);
+	}
 
+	void VirtualTTY::update_cursor()
+	{
+		static bool last_shown = !m_cursor_shown;
+		if (m_cursor_shown != last_shown)
+			m_terminal_driver->set_cursor_shown(m_cursor_shown);
+		last_shown = m_cursor_shown;
+
+		static uint32_t last_column = -1;
+		static uint32_t last_row = -1;
+		if (last_column != m_column || last_row != m_row)
 			m_terminal_driver->set_cursor_position(m_column, m_row);
+		last_column = m_column;
+		last_row = m_row;
 	}
 
 }