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>

1 files changed, 6 insertions, 0 deletions

diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c
index be313e791e67..a6ad68865880 100644
--- 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;