Re: TAKE 964002 - Don't wait for pending I/Os when purging blocks beyond eof.

[Christoph Hellwig <hch@infradead.org>]

On Wed, Dec 12, 2007 at 10:25:17AM +1100, David Chinner wrote:
> > which is wrong given that we don't wait for all pending direct I/O
> > requests..  (and vn_iowait doesn't wait for direct I/O anyway)
> 
> vn_iowait() does wait for direct I/O. That was it's entire purpose - to be
> able to prevent truncate vs direct I/O write races by tracking direct I/Os.
> We increment ip->i_iocount in xfs_alloc_ioend() which is called from both the
> buffered write and direct I/O write path, so vn_iowait() does wait for both
> buffered and direct writes to complete.

Sorry, forgot a little important word above - it should read
'and vn_iowait doesn't wait _just_ for direct I/O anyway), because it
waits for completion of regular I/O aswell.  Not that it should actually
matter in that caller.forgot a little important word above - it should
read
'and vn_iowait doesn't wait _just_ for direct I/O anyway), because it
waits for completion of regular I/O aswell.  Not that it should actually
matter in that caller.