tree 7ae1fda9f3512f9fabd1cc6d2467b4a9c416d745
parent f3324a2a94c229831cfd42d871902cd4a9bd5e0f
author NeilBrown <neilb@suse.de> 1405301300 +1000
committer Trond Myklebust <trond.myklebust@primarydata.com> 1407100452 -0400

NFS: teach nfs_neg_need_reval to understand LOOKUP_RCU

This requires nfs_check_verifier to take an rcu_walk flag, and requires
an rcu version of nfs_revalidate_inode which returns -ECHILD rather
than making an RPC call.

With this, nfs_lookup_revalidate can call nfs_neg_need_reval in
RCU-walk mode.

We can also move the LOOKUP_RCU check past the nfs_check_verifier()
call in nfs_lookup_revalidate.

If RCU_WALK prevents nfs_check_verifier or nfs_neg_need_reval from
doing a full check, they return a status indicating that a revalidation
is required.  As this revalidation will not be possible in RCU_WALK
mode, -ECHILD will ultimately be returned, which is the desired result.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>