Re: which dentry a page belongs to

[Shaya Potter <spotter@cs.columbia.edu>]

On Fri, 2004-04-23 at 18:22 +0100, Christoph Hellwig wrote:
> On Fri, Apr 23, 2004 at 01:18:27PM -0400, Shaya Potter wrote:
> > > you can be in writepage with page->mapping->i_mmap{,shared} beeing empty.
> > > No way in hell you'll ever get to a dentry.
> > 
> > the question being in what cases will that happen, so I can make a
> > determination if I care about those cases.  (i.e. if the dentry is
> > deleted, I don't particularly care, as since I am versioning, if it's
> > already been deleted, don't care)
> > 
> > i.e. how can I determine where i_mmap{,shared} exist and when does't it?
> > (in file system page context).
> 
> if there's no mapping anymore at the point of the writeback.  e.g. when
> an munmap happened before the writeback is scheduled.  And you can't
> determine it except  by checking whether it's empty.

so that could be very repeatable if a process does a write to memory and
then quits.  hmm.

> p.s. wondering what strange homework assignments they give these days..

not homework, research project.   and yes, it is strange. :)  I'm
finished w/ my course work.