Re: i_version changes

[Andreas Dilger <adilger@sun.com>]

On Feb 12, 2008  15:06 -0500, J. Bruce Fields wrote:
> On Sun, Feb 10, 2008 at 08:30:41AM +0100, Christoph Hellwig wrote:
> > Third using the MS_ flag but then actually having a filesystem
> > mount option to enable it is more than confusing.  After all MS_
> > options (at least the exported parts) are the mount ABI for common
> > options.  Also this option doesn't show up in ->show_options,
> > which is something Miklos will beat you up for :)
> > I'm also not convinced this should be option behaviour, either you
> > do update i_version for a given filesystem or you don't - having
> > an obscure mount option will only give you confusion.
> 
> That does sound likely to be confusing.  Any chance we could just make
> the new behavior mandatory?

One of the reasons NOT to make it mandatory is that it forces updates
of the inode after every write.  On ext3/ext4 this is expensive, as the
ext3_dirty_inode() packs the inode from memory into the buffer each time,
so that it can be journaled.

Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.