Re: [patch 8/8] fs: add i_op->sync_inode

[Nick Piggin <npiggin@kernel.dk>]

On Tue, Jan 04, 2011 at 07:03:23PM +1100, Nick Piggin wrote:
> On Tue, Jan 04, 2011 at 01:57:37AM -0500, Christoph Hellwig wrote:
> > > Also giving filesystems the flexibility to do the data writeout can
> > > be more optimal by doing all writeout at once or ordering to suit their
> > > writeback patterns. Having range data could give some performance
> > > advantages writing back mappings or commit operations over network. I
> > > don't see it as a big complexity. It gives a chance to do range fsyncs
> > > and sync_file_range and such properly too.
> > 
> > We currently do all that just fine before calling into ->fsync.
> 
> What do you mean we do all that just fine? A filesystem can't schedule
> data submission and waiting optimally versus metadata, it can't do
> metadata operations or remote commits corresponding to data ranges, and
> it doesn't support nfs sync operations.

And actually I think it is much better to have sync_inode, which means
we'll be able to get rid of commit_metadata (which should be an inode
operation anyway, not an export operation which really should deal with
exporting filesystems to a non-vfs namespace, not nfsd hacks).

commit_metadata would just be sync_inode with a null range or no data
sync flag set.