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