NFS: Teach nfs_try_to_update_request() to deal with request page_groups

Simplify the code, and avoid some flushes to disk.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
This commit is contained in:
Trond Myklebust 2017-07-17 19:50:23 -04:00
commit f6032f216f