On Wed, Jun 22, 2011 at 11:09:11AM +1000, Dave Chinner wrote:

All good, except I think there's a small problem with this - we have
to process the ioends before pages will transition from WRITEBACK to
clean. i.e. it is not until xfs_ioend_destroy() that we call the
bh->b_end_io() function to update the page state. Hence it would
have to be:

xfs_fsync() {

	current->journal_info = &ioend_end_list;

	filemap_fdatawrite();

	list_for_each_entry_reverse(ioend_end_list) {
		/* process_ioend also waits for ioend completion */
		process_ioend();
	}

	current->journal_info = NULL;

	filemap_fdatawait();

Indeed.

Direct IO is another matter, but we've already got an
xfs_ioend_wait() in xfs_fsync() to deal with that. Perhaps that
could be moved over to your new DIO counter so we do block on all
pending IO?

Splitting the pending direct I/O requests into the one is indeed the
plan.  We'll still need to track ioends for them, though - and I haven't
though about thedetails for those yet.

quoted

If that sounds reasonable I'll respin a series to move to
per-mount workqueues, remove the EAGAIN case, and use the workqueue
flush in sync.  Fsync will be left for later, and I'll ping Josef to
resend his fsync prototype change.

Yes, sounds like a plan.

I've implemented it yesterday, and it appears to work fine.  But there's
another issues I found:  the flush_workqueue will update i_size and mark
the inodes dirty right now from ->sync_fs, but that's after we've done
the VFS writeback.  I guess I nees to order this patch after the one
I'm working on to stop doing non-transaction inode updates.

_______________________________________________
xfs mailing list
xfs@oss.sgi.com
http://oss.sgi.com/mailman/listinfo/xfs