Re: review [1 of 3]: lazy superblock counters - core kernel

[Christoph Hellwig <hch@xxxxxxxxxxxxx>]

On Tue, Apr 24, 2007 at 08:16:23AM +1000, David Chinner wrote:
> > > +                 INT_SET(sb->sb_fdblocks, ARCH_CONVERT, 
> > > mp->m_sb.sb_fdblocks);
> > > +                 XFS_SB_UNLOCK(mp, s);
> > 
> > This is really quite nasty.  Should we at least force a cache flush here?
> 
> Well, that is what it's doing - xfs_log_sbcount() flushes the counters and
> logs the changes to the superblock. If that fails (very rare) we've already
> got the current values in mp->m_sb and so all we need to do is push them
> into the disk superblock and write it.

Sorry, should have been more detailed.  I meant the disk cache, as in
blkdev_issue_flush, to make sure the data hits the disk, even if it doesn't
go through a transaction which would normally do that. (in the barriers case)