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

[Andrea Righi]

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.

Thanks,
-Andrea