[PATCH 2/3] NFS: Properly handle the case where the delegation is revoked

[andros@netapp.com]

From: Trond Myklebust <Trond.Myklebust@netapp.com>

If we know that the delegation stateid is bad or revoked, we need to
remove that delegation as soon as possible, and then mark all the
stateids that relied on that delegation for recovery. We cannot use
the delegation as part of the recovery process.

Also note that NFSv4.1 uses a different error code (NFS4ERR_DELEG_REVOKED)
to indicate that the delegation was revoked.

Finally, ensure that setlk() and setattr() can both recover safely from
a revoked delegation.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org
---
 fs/nfs/delegation.c |   11 +++++++++++
 fs/nfs/delegation.h |    1 +
 fs/nfs/nfs4_fs.h    |    2 ++
 fs/nfs/nfs4proc.c   |   16 ++++++++++++++--
 fs/nfs/nfs4state.c  |   26 ++++++++++++++++++++++++++
 5 files changed, 54 insertions(+), 2 deletions(-)

diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c
index 1596098..c14512c 100644
--- a/fs/nfs/delegation.c
+++ b/fs/nfs/delegation.c
@@ -466,6 +466,17 @@ static void nfs_delegation_run_state_manager(struct nfs_client *clp)
 		nfs4_schedule_state_manager(clp);
 }
 
+void nfs_remove_bad_delegation(struct inode *inode)
+{
+	struct nfs_delegation *delegation;
+
+	delegation = nfs_detach_delegation(NFS_I(inode), NFS_SERVER(inode));
+	if (delegation) {
+		nfs_inode_find_state_and_recover(inode, &delegation->stateid);
+		nfs_free_delegation(delegation);
+	}
+}
+
 /**
  * nfs_expire_all_delegation_types
  * @clp: client to process
diff --git a/fs/nfs/delegation.h b/fs/nfs/delegation.h
index d9322e4..691a796 100644
--- a/fs/nfs/delegation.h
+++ b/fs/nfs/delegation.h
@@ -45,6 +45,7 @@ void nfs_expire_unreferenced_delegations(struct nfs_client *clp);
 void nfs_handle_cb_pathdown(struct nfs_client *clp);
 int nfs_client_return_marked_delegations(struct nfs_client *clp);
 int nfs_delegations_present(struct nfs_client *clp);
+void nfs_remove_bad_delegation(struct inode *inode);
 
 void nfs_delegation_mark_reclaim(struct nfs_client *clp);
 void nfs_delegation_reap_unclaimed(struct nfs_client *clp);
diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h
index b133b50..6b53cca 100644
--- a/fs/nfs/nfs4_fs.h
+++ b/fs/nfs/nfs4_fs.h
@@ -318,6 +318,8 @@ extern void nfs4_put_open_state(struct nfs4_state *);
 extern void nfs4_close_state(struct nfs4_state *, fmode_t);
 extern void nfs4_close_sync(struct nfs4_state *, fmode_t);
 extern void nfs4_state_set_mode_locked(struct nfs4_state *, fmode_t);
+extern void nfs_inode_find_state_and_recover(struct inode *inode,
+		const nfs4_stateid *stateid);
 extern void nfs4_schedule_lease_recovery(struct nfs_client *);
 extern void nfs4_schedule_state_manager(struct nfs_client *);
 extern void nfs4_schedule_path_down_recovery(struct nfs_client *clp);
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 0d5134a..2722388 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -267,8 +267,11 @@ static int nfs4_handle_exception(struct nfs_server *server, int errorcode, struc
 	switch(errorcode) {
 		case 0:
 			return 0;
+		case -NFS4ERR_DELEG_REVOKED:
 		case -NFS4ERR_ADMIN_REVOKED:
 		case -NFS4ERR_BAD_STATEID:
+			if (state != NULL)
+				nfs_remove_bad_delegation(state->inode);
 		case -NFS4ERR_OPENMODE:
 			if (state == NULL)
 				break;
@@ -1329,6 +1332,7 @@ int nfs4_open_delegation_recall(struct nfs_open_context *ctx, struct nfs4_state
 				 * The show must go on: exit, but mark the
 				 * stateid as needing recovery.
 				 */
+			case -NFS4ERR_DELEG_REVOKED:
 			case -NFS4ERR_ADMIN_REVOKED:
 			case -NFS4ERR_BAD_STATEID:
 				nfs4_schedule_stateid_recovery(server, state);
@@ -1929,7 +1933,9 @@ static int nfs4_do_setattr(struct inode *inode, struct rpc_cred *cred,
 			   struct nfs4_state *state)
 {
 	struct nfs_server *server = NFS_SERVER(inode);
-	struct nfs4_exception exception = { };
+	struct nfs4_exception exception = {
+		.state = state,
+	};
 	int err;
 	do {
 		err = nfs4_handle_exception(server,
@@ -3753,8 +3759,11 @@ nfs4_async_handle_error(struct rpc_task *task, const struct nfs_server *server,
 	if (task->tk_status >= 0)
 		return 0;
 	switch(task->tk_status) {
+		case -NFS4ERR_DELEG_REVOKED:
 		case -NFS4ERR_ADMIN_REVOKED:
 		case -NFS4ERR_BAD_STATEID:
+			if (state != NULL)
+				nfs_remove_bad_delegation(state->inode);
 		case -NFS4ERR_OPENMODE:
 			if (state == NULL)
 				break;
@@ -4595,7 +4604,9 @@ out:
 
 static int nfs4_proc_setlk(struct nfs4_state *state, int cmd, struct file_lock *request)
 {
-	struct nfs4_exception exception = { };
+	struct nfs4_exception exception = {
+		.state = state,
+	};
 	int err;
 
 	do {
@@ -4688,6 +4699,7 @@ int nfs4_lock_delegation_recall(struct nfs4_state *state, struct file_lock *fl)
 				 * The show must go on: exit, but mark the
 				 * stateid as needing recovery.
 				 */
+			case -NFS4ERR_DELEG_REVOKED:
 			case -NFS4ERR_ADMIN_REVOKED:
 			case -NFS4ERR_BAD_STATEID:
 			case -NFS4ERR_OPENMODE:
diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index 653bfd7..7bd9822 100644
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -1103,6 +1103,32 @@ void nfs4_schedule_stateid_recovery(const struct nfs_server *server, struct nfs4
 	nfs4_schedule_state_manager(clp);
 }
 
+void nfs_inode_find_state_and_recover(struct inode *inode,
+		const nfs4_stateid *stateid)
+{
+	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
+	struct nfs_inode *nfsi = NFS_I(inode);
+	struct nfs_open_context *ctx;
+	struct nfs4_state *state;
+	bool found = false;
+
+	spin_lock(&inode->i_lock);
+	list_for_each_entry(ctx, &nfsi->open_files, list) {
+		state = ctx->state;
+		if (state == NULL)
+			continue;
+		if (!test_bit(NFS_DELEGATED_STATE, &state->flags))
+			continue;
+		if (memcmp(state->stateid.data, stateid->data, sizeof(state->stateid.data)) != 0)
+			continue;
+		nfs4_state_mark_reclaim_nograce(clp, state);
+		found = true;
+	}
+	spin_unlock(&inode->i_lock);
+	if (found)
+		nfs4_schedule_state_manager(clp);
+}
+
 static int nfs4_reclaim_locks(struct nfs4_state *state, const struct nfs4_state_recovery_ops *ops)
 {
 	struct inode *inode = state->inode;
-- 
1.7.6.4