Re: + fs-introduce-write_begin-write_end-and-perform_write-aops.patch added to -mm tree

[Andrew Morton <akpm@linux-foundation.org>]

On Wed, 30 May 2007 05:13:54 +0200 Nick Piggin <npiggin@suse.de> wrote:

> On Tue, May 29, 2007 at 02:19:55PM -0700, Andrew Morton wrote:
> > 
> > The patch titled
> >      fs: introduce write_begin, write_end, and perform_write aops
> > has been added to the -mm tree.  Its filename is
> >      fs-introduce-write_begin-write_end-and-perform_write-aops.patch
> > 
> > *** Remember to use Documentation/SubmitChecklist when testing your code ***
> > 
> > See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
> > out what to do about this
> > 
> > ------------------------------------------------------
> > Subject: fs: introduce write_begin, write_end, and perform_write aops
> > From: Nick Piggin <npiggin@suse.de>
> > 
> > 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).
> 
> OK, well now Andrew's merged a significant chunk of this work, I
> would like to try getting the clustered filesystem patches back
> in too (Steven, the last GFS2 patch you sent had rejects against this
> tree, so I dropped it... hope it isn't too much work to bring it back
> uptodate?).
>
> The cluster filesystems aren't 100% happy with the backward-compat
> code, because pagecache_write_end cannot handle AOP_TRUNCATED_PAGE from
> ->commit_write... so if you were to try using loop over GFS2, it might
> go BUG. This is a bit bad of me, however the compat code would have been
> a whole lot uglier to support that, and I figure the cluster filesystems
> want to convert to the new aops ASAP anyway.
> 
> I doubt anybody but the filesystem developers would be using -mm in such
> a way, but even so I hope we can fix this before long.
> 
> Meanwhile, I'll look at redoing the rest of the filesystems that got
> left behind.

hm, I suppose that means I need to undrop git-ocfs2.patch.  It has a mild
disagreeement with the fault-vs-invalidate patches which I didn't feel like
fixing.