spurious -ENOSPC on XFS

[Christoph Hellwig]

On Wed, Jan 21, 2009 at 10:24:22AM +1100, Dave Chinner wrote:
> Right, so you need to use internal xfs sync functions that don't
> have these problems. That is:
> 
> 	error = xfs_sync_inodes(ip->i_mount, SYNC_DELWRI|SYNC_WAIT);
> 
> will do a blocking flush of all the inodes without deadlocks occurring.
> Then you can remove the 500ms wait.

I've given this a try with Eric's testcase from #724 in the oss bugzilla,
but it's not enough yet.  I thinks that's because SYNC_WAIT is rather
meaningless for data writeout, and we need SYNC_IOWAIT instead.  The
patch below gets the testcase working for me:


Index: linux-2.6/fs/xfs/linux-2.6/xfs_sync.c
===================================================================
--- linux-2.6.orig/fs/xfs/linux-2.6/xfs_sync.c	2009-01-22 06:29:30.646141628 +0100
+++ linux-2.6/fs/xfs/linux-2.6/xfs_sync.c	2009-01-22 21:57:53.073864570 +0100
@@ -446,7 +446,9 @@ xfs_flush_device_work(
 	void		*arg)
 {
 	struct inode	*inode = arg;
-	sync_blockdev(mp->m_super->s_bdev);
+
+	xfs_sync_inodes(mp, SYNC_DELWRI);
+	xfs_sync_inodes(mp, SYNC_DELWRI | SYNC_IOWAIT);
 	iput(inode);
 }