Re: Direct IO and Page cache

On Thu, 25 Jul 2013 23:15:49 -0400, Kumar amit mehta said:

applications are being written. So one bad day somebody comes up with an application which does both these two types of IO(one that goes through page cache and the other that doesn't) and in that application, one instance is writing directly to the backend device and the other instance, who is not aware of this write, goes ahead and writes to the page cache, and that write would be written later to the backend device. So wouldn't we end up corrupting the on disk data.

Applications that intermix O_DIRECT and non-O_DIRECT to the same file get what they deserve. Consider it evolution in action, you're not going to get any sympathy from the kernel community for this.