Re: [PATCH 2/3] Fix fsync livelock

[Dave Chinner]

On Sun, Oct 05, 2008 at 08:01:46PM -0400, Mikulas Patocka wrote:
> This looks madly complicated. And ineffective, because if some page was 
> submitted before fsync() was invoked, and is under writeback while fsync() 
> is called, fsync() still has to wait on it.

fsync() waiting on pre-issued writeback pages is the correct
behaviour.

IOW, if the page is under writeback at the time an fsync() is
issued (e.g. issued by pdflush), the page was *not clean* at the
time the fsync() was called and hence must be clean when fsync()
returns. fsync() needs to wait for all pages under I/O at the time
it is called, not just the dirty pages it issues I/O on.....

Cheers,

Dave.
-- 
Dave Chinner
david@xxxxxxxxxxxxx
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/