Merge tag 'fscache-fixes-20200508-2' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

 (1) The reorganisation of bmap() use accidentally caused the return value
     of cachefiles_read_or_alloc_pages() to get corrupted.

 (2) The NFS superblock index key accidentally got changed to include a
     number of kernel pointers - meaning that the key isn't matchable after
     a reboot.

 (3) A redundant check in nfs_fscache_get_super_cookie().

 (4) The NFS change_attr sometimes set in the auxiliary data for the
     caching of an file and sometimes not, which causes the cache to get
     discarded when it shouldn't.

 (5) There's a race between cachefiles_read_waiter() and
     cachefiles_read_copier() that causes an occasional assertion failure.