If you need to execute ioctl(2) with FIONREAD after changing the file size (*1) to the same file, perform both operations on the same node.
*1 File size change using a command such as write(2), truncate(2), or ftruncate(2)
If you execute the ioctl(2) after changing the file size for the same file from the other node, the file might calculate the prefetch quantity based on the old file size. You can prevent this problem by acquiring (*2) updated file size before executing the command.
*2 File information acquisition using a command such as stat(1), stat(2), or fstat(2)
