On Wed, Jan 18, 2023 at 04:08:57PM +0000, Matthew Wilcox wrote: > On Wed, Jan 18, 2023 at 10:43:28AM +0100, Christoph Hellwig wrote: > > filemap_get_folio can return NULL, skip those cases. > > Hmm, I'm not sure that's true. We have one place that calls > extent_range_redirty_for_io(), and it previously calls > extent_range_clear_dirty_for_io() which has an explicit > > BUG_ON(!page); /* Pages should be in the extent_io_tree */ > > so I'm going to say this one can't happen either. I haven't delved far > enough into btrfs to figure out why it can't happen. I'll drop this patch for now.
