Re: [patch 2/5] fs: introduce new aops and infrastructure

[Trond Myklebust <trond.myklebust@fys.uio.no>]

On Wed, 2007-03-14 at 21:13 -0700, Mark Fasheh wrote:
> Hi Nick,
> 
> On Wed, Mar 14, 2007 at 02:38:22PM +0100, Nick Piggin wrote:
> > Introduce write_begin, write_end, and perform_write aops.
> > 
> > These are intended to replace prepare_write and commit_write with more
> > flexible alternatives that are also able to avoid the buffered write
> > deadlock problems efficiently (which prepare_write is unable to do).
> 
> > Index: linux-2.6/include/linux/fs.h
> > ===================================================================
> > --- linux-2.6.orig/include/linux/fs.h
> > +++ linux-2.6/include/linux/fs.h
> > @@ -449,6 +449,17 @@ struct address_space_operations {
> >  	 */
> >  	int (*prepare_write)(struct file *, struct page *, unsigned, unsigned);
> >  	int (*commit_write)(struct file *, struct page *, unsigned, unsigned);
> > +
> > +	int (*write_begin)(struct file *, struct address_space *mapping,
> > +				loff_t pos, unsigned len, int intr,
> > +				struct page **pagep, void **fsdata);
> > +	int (*write_end)(struct file *, struct address_space *mapping,
> > +				loff_t pos, unsigned len, unsigned copied,
> > +				struct page *page, void *fsdata);
> 
> Are we going to get rid of the file and intr arguments btw? I'm not sure
> intr is useful, and mapping is probably enough to get whatever we inside
> ->write_begin / ->write_end.

Hell no! Struct file carries information that is essential for those of
us that use strong authentication. It stays.

Trond