1 files changed, 74 insertions, 14 deletions

diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c
index 1819d0d0ba4b..f033f3a69a3b 100644
--- a/fs/nfs/delegation.c
+++ b/fs/nfs/delegation.c
@@ -404,6 +404,10 @@ int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred,
 
 	trace_nfs4_set_delegation(inode, type);
 
+	spin_lock(&inode->i_lock);
+	if (NFS_I(inode)->cache_validity & (NFS_INO_INVALID_ATTR|NFS_INO_INVALID_ATIME))
+		NFS_I(inode)->cache_validity |= NFS_INO_REVAL_FORCED;
+	spin_unlock(&inode->i_lock);
 out:
 	spin_unlock(&clp->cl_lock);
 	if (delegation != NULL)
@@ -483,38 +487,88 @@ out:
 int nfs_client_return_marked_delegations(struct nfs_client *clp)
 {
 	struct nfs_delegation *delegation;
+	struct nfs_delegation *prev;
 	struct nfs_server *server;
 	struct inode *inode;
+	struct inode *place_holder = NULL;
+	struct nfs_delegation *place_holder_deleg = NULL;
 	int err = 0;
 
 restart:
+	/*
+	 * To avoid quadratic looping we hold a reference
+	 * to an inode place_holder.  Each time we restart, we
+	 * list nfs_servers from the server of that inode, and
+	 * delegation in the server from the delegations of that
+	 * inode.
+	 * prev is an RCU-protected pointer to a delegation which
+	 * wasn't marked for return and might be a good choice for
+	 * the next place_holder.
+	 */
 	rcu_read_lock();
-	list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
-		list_for_each_entry_rcu(delegation, &server->delegations,
-								super_list) {
-			if (!nfs_delegation_need_return(delegation))
+	prev = NULL;
+	if (place_holder)
+		server = NFS_SERVER(place_holder);
+	else
+		server = list_entry_rcu(clp->cl_superblocks.next,
+					struct nfs_server, client_link);
+	list_for_each_entry_from_rcu(server, &clp->cl_superblocks, client_link) {
+		delegation = NULL;
+		if (place_holder && server == NFS_SERVER(place_holder))
+			delegation = rcu_dereference(NFS_I(place_holder)->delegation);
+		if (!delegation || delegation != place_holder_deleg)
+			delegation = list_entry_rcu(server->delegations.next,
+						    struct nfs_delegation, super_list);
+		list_for_each_entry_from_rcu(delegation, &server->delegations, super_list) {
+			struct inode *to_put = NULL;
+
+			if (!nfs_delegation_need_return(delegation)) {
+				prev = delegation;
 				continue;
+			}
 			if (!nfs_sb_active(server->super))
-				continue;
+				break; /* continue in outer loop */
+
+			if (prev) {
+				struct inode *tmp;
+
+				tmp = nfs_delegation_grab_inode(prev);
+				if (tmp) {
+					to_put = place_holder;
+					place_holder = tmp;
+					place_holder_deleg = prev;
+				}
+			}
+
 			inode = nfs_delegation_grab_inode(delegation);
 			if (inode == NULL) {
 				rcu_read_unlock();
+				if (to_put)
+					iput(to_put);
 				nfs_sb_deactive(server->super);
 				goto restart;
 			}
 			delegation = nfs_start_delegation_return_locked(NFS_I(inode));
 			rcu_read_unlock();
 
+			if (to_put)
+				iput(to_put);
+
 			err = nfs_end_delegation_return(inode, delegation, 0);
 			iput(inode);
 			nfs_sb_deactive(server->super);
+			cond_resched();
 			if (!err)
 				goto restart;
 			set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
+			if (place_holder)
+				iput(place_holder);
 			return err;
 		}
 	}
 	rcu_read_unlock();
+	if (place_holder)
+		iput(place_holder);
 	return 0;
 }
 
@@ -802,12 +856,14 @@ nfs_delegation_find_inode_server(struct nfs_server *server,
 		if (delegation->inode != NULL &&
 		    nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
 			res = igrab(delegation->inode);
+			spin_unlock(&delegation->lock);
+			if (res != NULL)
+				return res;
+			return ERR_PTR(-EAGAIN);
 		}
 		spin_unlock(&delegation->lock);
-		if (res != NULL)
-			break;
 	}
-	return res;
+	return ERR_PTR(-ENOENT);
 }
 
 /**
@@ -822,16 +878,18 @@ struct inode *nfs_delegation_find_inode(struct nfs_client *clp,
 					const struct nfs_fh *fhandle)
 {
 	struct nfs_server *server;
-	struct inode *res = NULL;
+	struct inode *res;
 
 	rcu_read_lock();
 	list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 		res = nfs_delegation_find_inode_server(server, fhandle);
-		if (res != NULL)
-			break;
+		if (res != ERR_PTR(-ENOENT)) {
+			rcu_read_unlock();
+			return res;
+		}
 	}
 	rcu_read_unlock();
-	return res;
+	return ERR_PTR(-ENOENT);
 }
 
 static void nfs_delegation_mark_reclaim_server(struct nfs_server *server)
@@ -887,7 +945,7 @@ restart:
 						&delegation->flags) == 0)
 				continue;
 			if (!nfs_sb_active(server->super))
-				continue;
+				break; /* continue in outer loop */
 			inode = nfs_delegation_grab_inode(delegation);
 			if (inode == NULL) {
 				rcu_read_unlock();
@@ -904,6 +962,7 @@ restart:
 			}
 			iput(inode);
 			nfs_sb_deactive(server->super);
+			cond_resched();
 			goto restart;
 		}
 	}
@@ -995,7 +1054,7 @@ restart:
 						&delegation->flags) == 0)
 				continue;
 			if (!nfs_sb_active(server->super))
-				continue;
+				break; /* continue in outer loop */
 			inode = nfs_delegation_grab_inode(delegation);
 			if (inode == NULL) {
 				rcu_read_unlock();
@@ -1020,6 +1079,7 @@ restart:
 			}
 			iput(inode);
 			nfs_sb_deactive(server->super);
+			cond_resched();
 			goto restart;
 		}
 	}