[PATCH v5 40/40] 9p: Use netfslib read/write_iter

[David Howells]

Andrea Righi <andrea.righi at canonical.com> wrote:

> On Thu, Dec 21, 2023 at 01:23:35PM +0000, David Howells wrote:
> > Use netfslib's read and write iteration helpers, allowing netfslib to take
> > over the management of the page cache for 9p files and to manage local disk
> > caching.  In particular, this eliminates write_begin, write_end, writepage
> > and all mentions of struct page and struct folio from 9p.
> > 
> > Note that netfslib now offers the possibility of write-through caching if
> > that is desirable for 9p: just set the NETFS_ICTX_WRITETHROUGH flag in
> > v9inode->netfs.flags in v9fs_set_netfs_context().
> > 
> > Note also this is untested as I can't get ganesha.nfsd to correctly parse
> > the config to turn on 9p support.
> 
> It looks like this patch has introduced a regression with autopkgtest,
> see: https://bugs.launchpad.net/bugs/2056461
> 
> I haven't looked at the details yet, I just did some bisecting and
> apparently reverting this one seems to fix the problem.
> 
> Let me know if you want me to test something in particular or if you
> already have a potential fix. Otherwise I'll take a look.

Do you have a reproducer?

I'll be at LSF next week, so if I can't fix it tomorrow, I won't be able to
poke at it until after that.

David