I found a couple of issues here: Firstly, netfs_is_cache_enabled() causes the generic/522 xfstest to take 60s longer. This can be fixed by: - return fscache_cookie_valid(cookie) && fscache_cookie_enabled(cookie); + return fscache_cookie_valid(cookie) && cookie->cache_priv && + fscache_cookie_enabled(cookie); There's no point trying to do caching if there's no cache actually attached. I wonder if I should actually make this change in fscache_cookie_enabled() rather than here. Secondly, the above causes netfs_skip_folio_read() to be skipped a lot more often than it should, and this hides an incorrect change there. I made netfs_skip_folio_read() copy the folio size into a variable to avoid issuing the calculation multiple times, but I then gave the wrong length when clearing the tail of the page. This can be fixed by: - zero_user_segments(&folio->page, 0, offset, offset + len, len); + zero_user_segments(&folio->page, 0, offset, offset + len, plen); David
