fs: allow BtrfsIoctlLogicalInoArgs to be reused, remove virtual methods

Some malloc implementations will try to mmap() and munmap() large buffers
every time they are used, causing a severe loss of performance.

Nothing ever overrode the virtual methods, and there was no virtual
destructor, so they cause compiler warnings at build time when used with
a template that tries to delete pointers to them.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>

lib/fs.cc

@@ -315,6 +315,18 @@ namespace crucible {
 		return m_flags;
 	}
 
+	void
+	BtrfsIoctlLogicalInoArgs::set_logical(uint64_t new_logical)
+	{
+		m_logical = new_logical;
+	}
+
+	void
+	BtrfsIoctlLogicalInoArgs::set_size(uint64_t new_size)
+	{
+		m_container_size = new_size;
+	}
+
 	bool
 	BtrfsIoctlLogicalInoArgs::do_ioctl_nothrow(int fd)
 	{