[zlynx]

This is an interesting example because the kernel's open() interface blocks for 4,000 ms all the time. Heavy swapping or the ext3 journal is full and some other app just called fsync().

Apps have to handle it. If they don't, because for example, they access the disk while also trying to be a display compositor, then they are simply broken. It does not matter if the kernel is usually fast enough. Because sometimes it isn't.