Re: Getting FS access events

Alexander Viro
2001-05-15T10:44:22Z

On Tue, 15 May 2001, Daniel Phillips wrote:

> That's because you left out his invalidate:
>
> * create an instance in pagecache
> * start reading into buffer cache (doesn't invalidate, right?)
> * start writing using pagecache (invalidate buffer copy)

Bzzert. You have a race here. Let's make it explicit:

start writing
put write request in queue
block on that
start reading into buffer cache
put read request into queue
read from media
write to media

And no, we can't invalidate from IO completion hook.

> * lose the page
> * try to read it (via pagecache)
>
> Everthing ok.

Nope.