[PATCH v3 13/20] netfs: Add a netfs inode context

[David Howells]

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