From 45870d6909d5a1f702d2a3781d8fc831301d13c8 Mon Sep 17 00:00:00 2001
From: Trond Myklebust <trond.myklebust@primarydata.com>
Date: Thu, 22 Sep 2016 13:38:59 -0400
Subject: NFSv4.1: Test delegation stateids when server declares "some state
 revoked"

According to RFC5661, if any of the SEQUENCE status bits
SEQ4_STATUS_EXPIRED_ALL_STATE_REVOKED,
SEQ4_STATUS_EXPIRED_SOME_STATE_REVOKED, SEQ4_STATUS_ADMIN_STATE_REVOKED,
or SEQ4_STATUS_RECALLABLE_STATE_REVOKED are set, then we need to use
TEST_STATEID to figure out which stateids have been revoked, so we
can acknowledge the loss of state using FREE_STATEID.

While we already do this for open and lock state, we have not been doing
so for all the delegations.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Tested-by: Oleg Drokin <green@linuxhacker.ru>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
---
 fs/nfs/delegation.c | 97 ++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 96 insertions(+), 1 deletion(-)

(limited to 'fs/nfs/delegation.c')

diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c
index e5212e5c73d2..dfb300901f7e 100644
--- a/fs/nfs/delegation.c
+++ b/fs/nfs/delegation.c
@@ -812,8 +812,15 @@ static void nfs_delegation_mark_reclaim_server(struct nfs_server *server)
 {
 	struct nfs_delegation *delegation;
 
-	list_for_each_entry_rcu(delegation, &server->delegations, super_list)
+	list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
+		/*
+		 * If the delegation may have been admin revoked, then we
+		 * cannot reclaim it.
+		 */
+		if (test_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags))
+			continue;
 		set_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
+	}
 }
 
 /**
@@ -877,6 +884,94 @@ restart:
 	rcu_read_unlock();
 }
 
+static void nfs_mark_test_expired_delegation(struct nfs_server *server,
+	    struct nfs_delegation *delegation)
+{
+	clear_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
+	set_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags);
+	set_bit(NFS4CLNT_DELEGATION_EXPIRED, &server->nfs_client->cl_state);
+}
+
+static void nfs_delegation_mark_test_expired_server(struct nfs_server *server)
+{
+	struct nfs_delegation *delegation;
+
+	list_for_each_entry_rcu(delegation, &server->delegations, super_list)
+		nfs_mark_test_expired_delegation(server, delegation);
+}
+
+/**
+ * nfs_mark_test_expired_all_delegations - mark all delegations for testing
+ * @clp: nfs_client to process
+ *
+ * Iterates through all the delegations associated with this server and
+ * marks them as needing to be checked for validity.
+ */
+void nfs_mark_test_expired_all_delegations(struct nfs_client *clp)
+{
+	struct nfs_server *server;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
+		nfs_delegation_mark_test_expired_server(server);
+	rcu_read_unlock();
+}
+
+/**
+ * nfs_reap_expired_delegations - reap expired delegations
+ * @clp: nfs_client to process
+ *
+ * Iterates through all the delegations associated with this server and
+ * checks if they have may have been revoked. This function is usually
+ * expected to be called in cases where the server may have lost its
+ * lease.
+ */
+void nfs_reap_expired_delegations(struct nfs_client *clp)
+{
+	const struct nfs4_minor_version_ops *ops = clp->cl_mvops;
+	struct nfs_delegation *delegation;
+	struct nfs_server *server;
+	struct inode *inode;
+	struct rpc_cred *cred;
+	nfs4_stateid stateid;
+
+restart:
+	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 (test_bit(NFS_DELEGATION_RETURNING,
+						&delegation->flags))
+				continue;
+			if (test_bit(NFS_DELEGATION_TEST_EXPIRED,
+						&delegation->flags) == 0)
+				continue;
+			if (!nfs_sb_active(server->super))
+				continue;
+			inode = nfs_delegation_grab_inode(delegation);
+			if (inode == NULL) {
+				rcu_read_unlock();
+				nfs_sb_deactive(server->super);
+				goto restart;
+			}
+			cred = get_rpccred_rcu(delegation->cred);
+			nfs4_stateid_copy(&stateid, &delegation->stateid);
+			clear_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags);
+			rcu_read_unlock();
+			if (cred != NULL &&
+			    ops->test_and_free_expired(server, &stateid, cred) < 0) {
+				nfs_revoke_delegation(inode, &stateid);
+				nfs_inode_find_state_and_recover(inode, &stateid);
+			}
+			put_rpccred(cred);
+			iput(inode);
+			nfs_sb_deactive(server->super);
+			goto restart;
+		}
+	}
+	rcu_read_unlock();
+}
+
 /**
  * nfs_delegations_present - check for existence of delegations
  * @clp: client state handle
-- 
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