what happened to page_mkwrite? - was: Re: page_mkwrite seems broken
From: Anton Altaparmakov
Date: Mon Oct 24 2005 - 10:17:12 EST
Hi,
On Wed, 2005-02-09 at 14:28 +0000, Hugh Dickins wrote:
> On Fri, 4 Feb 2005, Hugh Dickins wrote in another thread:
> > Isn't this exactly what David Howells' page_mkwrite stuff in -mm's
> > add-page-becoming-writable-notification.patch is designed for?
> >
> > Though it looks a little broken to me as it stands (beyond the two
> > fixup patches already there). I've not found time to double-check
> > or test, apologies in advance if I'm libelling, but...
> >
> > (a) I thought the prot bits do_nopage gives a pte in a shared writable
> > mapping include write permission, even when it's a read fault:
> > that can't be allowed if there's a page_mkwrite.
> >
> > (b) I don't understand how do_wp_page's "reuse" logic for whether it
> > can just go ahead and use the existing anonymous page, would have
> > any relevance to calling page_mkwrite on a shared writable page,
> > which must be used and not COWed however many references there are.
>
> I have now looked further, and both points still seem valid to me:
> the page_mkwrite calling code looks doubly broken. (Tested?)
>
> Nor has there been any movement on the points raised by Christoph,
> that aops->page_mkwrite is redundant, and do_wp_page_mk_pte_writable
> separation unhelpful.
>
> I could probably put page_mkwrite to use in tmpfs (to eliminate its
> unsatisfactory but never over-troubling shmem_recalc_inode), but not
> as it currently stands.
>
> Are you planning any movement on this, David?
> Or should I have a go sometime?
What happened with page_mkwrite? It seems to have disappeared both from
-mm and generally from the face of the earth...
I am very interested in having such ability for ntfs...
Is anyone still working on this? If not why not? Did it prove
impractical or ...?
If no-one is working on this anymore, where do I find the last "current"
patch?
Thanks a lot in advance!
Best regards,
Anton
--
Anton Altaparmakov <aia21 at cam.ac.uk> (replace at with @)
Unix Support, Computing Service, University of Cambridge, CB2 3QH, UK
Linux NTFS maintainer / IRC: #ntfs on irc.freenode.net
WWW: http://linux-ntfs.sf.net/ & http://www-stu.christs.cam.ac.uk/~aia21/
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