gfs2: convert gfs2_getbuf() to folios

Remove several folio->page->folio conversions.  Also use __GFP_NOFAIL
instead of calling yield() and the new get_nth_bh().

Link: https://lkml.kernel.org/r/20231016201114.1928083-8-willy@infradead.org


Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Pankaj Raghav <p.raghav@samsung.com>
Cc: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>