NFSv4: Ensure we skip delegations that are already being returned

In nfs_client_return_marked_delegations() and nfs_delegation_reap_unclaimed()
we want to optimise the loop traversal by skipping delegations that are
already in the process of being returned.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c
index be313e7..a6ad688 100644 (file)
--- a/fs/nfs/delegation.c
+++ b/fs/nfs/delegation.c
@@ -436,6 +436,8 @@ static bool nfs_delegation_need_return(struct nfs_delegation *delegation)
 {
        bool ret = false;
 
+       if (test_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
+               goto out;
        if (test_and_clear_bit(NFS_DELEGATION_RETURN, &delegation->flags))
                ret = true;
        if (test_and_clear_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags) && !ret) {
@@ -447,6 +449,7 @@ static bool nfs_delegation_need_return(struct nfs_delegation *delegation)
                        ret = true;
                spin_unlock(&delegation->lock);
        }
+out:
        return ret;
 }
 
@@ -818,6 +821,9 @@ restart:
        list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
                list_for_each_entry_rcu(delegation, &server->delegations,
                                                                super_list) {
+                       if (test_bit(NFS_DELEGATION_RETURNING,
+                                               &delegation->flags))
+                               continue;
                        if (test_bit(NFS_DELEGATION_NEED_RECLAIM,
                                                &delegation->flags) == 0)
                                continue;