NFSv4.1: Fix open stateid recovery

The logic for checking in nfs41_check_open_stateid() whether the state
is supported by a delegation is inverted. In addition, it makes more
sense to perform that check before we check for expired locks.

Fixes: 8a64c4ef ("NFSv4.1: Even if the stateid is OK,...")
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

fs/nfs/nfs4proc.c

@@ -1683,6 +1683,14 @@ static void nfs_state_set_open_stateid(struct nfs4_state *state,
 	write_sequnlock(&state->seqlock);
 }
 
+static void nfs_state_clear_open_state_flags(struct nfs4_state *state)
+{
+	clear_bit(NFS_O_RDWR_STATE, &state->flags);
+	clear_bit(NFS_O_WRONLY_STATE, &state->flags);
+	clear_bit(NFS_O_RDONLY_STATE, &state->flags);
+	clear_bit(NFS_OPEN_STATE, &state->flags);
+}
+
 static void nfs_state_set_delegation(struct nfs4_state *state,
 		const nfs4_stateid *deleg_stateid,
 		fmode_t fmode)
@@ -2074,13 +2082,7 @@ static int nfs4_open_recover(struct nfs4_opendata *opendata, struct nfs4_state *
 {
 	int ret;
 
-	/* Don't trigger recovery in nfs_test_and_clear_all_open_stateid */
-	clear_bit(NFS_O_RDWR_STATE, &state->flags);
-	clear_bit(NFS_O_WRONLY_STATE, &state->flags);
-	clear_bit(NFS_O_RDONLY_STATE, &state->flags);
 	/* memory barrier prior to reading state->n_* */
-	clear_bit(NFS_DELEGATED_STATE, &state->flags);
-	clear_bit(NFS_OPEN_STATE, &state->flags);
 	smp_rmb();
 	ret = nfs4_open_recover_helper(opendata, FMODE_READ|FMODE_WRITE);
 	if (ret != 0)
@@ -2156,6 +2158,8 @@ static int nfs4_open_reclaim(struct nfs4_state_owner *sp, struct nfs4_state *sta
 	ctx = nfs4_state_find_open_context(state);
 	if (IS_ERR(ctx))
 		return -EAGAIN;
+	clear_bit(NFS_DELEGATED_STATE, &state->flags);
+	nfs_state_clear_open_state_flags(state);
 	ret = nfs4_do_open_reclaim(ctx, state);
 	put_nfs_open_context(ctx);
 	return ret;
@@ -2697,6 +2701,7 @@ static int nfs40_open_expired(struct nfs4_state_owner *sp, struct nfs4_state *st
 {
 	/* NFSv4.0 doesn't allow for delegation recovery on open expire */
 	nfs40_clear_delegation_stateid(state);
+	nfs_state_clear_open_state_flags(state);
 	return nfs4_open_expired(sp, state);
 }
 
@@ -2739,13 +2744,13 @@ static int nfs41_test_and_free_expired_stateid(struct nfs_server *server,
 	return -NFS4ERR_EXPIRED;
 }
 
-static void nfs41_check_delegation_stateid(struct nfs4_state *state)
+static int nfs41_check_delegation_stateid(struct nfs4_state *state)
 {
 	struct nfs_server *server = NFS_SERVER(state->inode);
 	nfs4_stateid stateid;
 	struct nfs_delegation *delegation;
 	const struct cred *cred = NULL;
-	int status;
+	int status, ret = NFS_OK;
 
 	/* Get the delegation credential for use by test/free_stateid */
 	rcu_read_lock();
@@ -2753,20 +2758,15 @@ static void nfs41_check_delegation_stateid(struct nfs4_state *state)
 	if (delegation == NULL) {
 		rcu_read_unlock();
 		nfs_state_clear_delegation(state);
-		return;
+		return NFS_OK;
 	}
 
 	nfs4_stateid_copy(&stateid, &delegation->stateid);
-	if (test_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) {
-		rcu_read_unlock();
-		nfs_state_clear_delegation(state);
-		return;
-	}
 
 	if (!test_and_clear_bit(NFS_DELEGATION_TEST_EXPIRED,
 				&delegation->flags)) {
 		rcu_read_unlock();
-		return;
+		return NFS_OK;
 	}
 
 	if (delegation->cred)
@@ -2776,8 +2776,24 @@ static void nfs41_check_delegation_stateid(struct nfs4_state *state)
 	trace_nfs4_test_delegation_stateid(state, NULL, status);
 	if (status == -NFS4ERR_EXPIRED || status == -NFS4ERR_BAD_STATEID)
 		nfs_finish_clear_delegation_stateid(state, &stateid);
+	else
+		ret = status;
 
 	put_cred(cred);
+	return ret;
+}
+
+static void nfs41_delegation_recover_stateid(struct nfs4_state *state)
+{
+	nfs4_stateid tmp;
+
+	if (test_bit(NFS_DELEGATED_STATE, &state->flags) &&
+	    nfs4_copy_delegation_stateid(state->inode, state->state,
+				&tmp, NULL) &&
+	    nfs4_stateid_match_other(&state->stateid, &tmp))
+		nfs_state_set_delegation(state, &tmp, state->state);
+	else
+		nfs_state_clear_delegation(state);
 }
 
 /**
@@ -2847,21 +2863,12 @@ static int nfs41_check_open_stateid(struct nfs4_state *state)
 	const struct cred *cred = state->owner->so_cred;
 	int status;
 
-	if (test_bit(NFS_OPEN_STATE, &state->flags) == 0) {
-		if (test_bit(NFS_DELEGATED_STATE, &state->flags) == 0)  {
-			if (nfs4_have_delegation(state->inode, state->state))
-				return NFS_OK;
-			return -NFS4ERR_OPENMODE;
-		}
+	if (test_bit(NFS_OPEN_STATE, &state->flags) == 0)
 		return -NFS4ERR_BAD_STATEID;
-	}
 	status = nfs41_test_and_free_expired_stateid(server, stateid, cred);
 	trace_nfs4_test_open_stateid(state, NULL, status);
 	if (status == -NFS4ERR_EXPIRED || status == -NFS4ERR_BAD_STATEID) {
-		clear_bit(NFS_O_RDONLY_STATE, &state->flags);
-		clear_bit(NFS_O_WRONLY_STATE, &state->flags);
-		clear_bit(NFS_O_RDWR_STATE, &state->flags);
-		clear_bit(NFS_OPEN_STATE, &state->flags);
+		nfs_state_clear_open_state_flags(state);
 		stateid->type = NFS4_INVALID_STATEID_TYPE;
 		return status;
 	}
@@ -2874,7 +2881,11 @@ static int nfs41_open_expired(struct nfs4_state_owner *sp, struct nfs4_state *st
 {
 	int status;
 
-	nfs41_check_delegation_stateid(state);
+	status = nfs41_check_delegation_stateid(state);
+	if (status != NFS_OK)
+		return status;
+	nfs41_delegation_recover_stateid(state);
+
 	status = nfs41_check_expired_locks(state);
 	if (status != NFS_OK)
 		return status;