1 files changed, 110 insertions, 76 deletions

diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c
index 7f37d1bea83..20ac403469a 100644
--- a/fs/nfs/delegation.c
+++ b/fs/nfs/delegation.c
@@ -27,6 +27,13 @@ static void nfs_free_delegation(struct nfs_delegation *delegation)
 	kfree(delegation);
 }
 
+static void nfs_free_delegation_callback(struct rcu_head *head)
+{
+	struct nfs_delegation *delegation = container_of(head, struct nfs_delegation, rcu);
+
+	nfs_free_delegation(delegation);
+}
+
 static int nfs_delegation_claim_locks(struct nfs_open_context *ctx, struct nfs4_state *state)
 {
 	struct inode *inode = state->inode;
@@ -57,7 +64,7 @@ out_err:
 	return status;
 }
 
-static void nfs_delegation_claim_opens(struct inode *inode)
+static void nfs_delegation_claim_opens(struct inode *inode, const nfs4_stateid *stateid)
 {
 	struct nfs_inode *nfsi = NFS_I(inode);
 	struct nfs_open_context *ctx;
@@ -72,9 +79,11 @@ again:
 			continue;
 		if (!test_bit(NFS_DELEGATED_STATE, &state->flags))
 			continue;
+		if (memcmp(state->stateid.data, stateid->data, sizeof(state->stateid.data)) != 0)
+			continue;
 		get_nfs_open_context(ctx);
 		spin_unlock(&inode->i_lock);
-		err = nfs4_open_delegation_recall(ctx->dentry, state);
+		err = nfs4_open_delegation_recall(ctx, state, stateid);
 		if (err >= 0)
 			err = nfs_delegation_claim_locks(ctx, state);
 		put_nfs_open_context(ctx);
@@ -115,10 +124,6 @@ int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct
 	struct nfs_delegation *delegation;
 	int status = 0;
 
-	/* Ensure we first revalidate the attributes and page cache! */
-	if ((nfsi->cache_validity & (NFS_INO_REVAL_PAGECACHE|NFS_INO_INVALID_ATTR)))
-		__nfs_revalidate_inode(NFS_SERVER(inode), inode);
-
 	delegation = kmalloc(sizeof(*delegation), GFP_KERNEL);
 	if (delegation == NULL)
 		return -ENOMEM;
@@ -131,10 +136,10 @@ int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct
 	delegation->inode = inode;
 
 	spin_lock(&clp->cl_lock);
-	if (nfsi->delegation == NULL) {
-		list_add(&delegation->super_list, &clp->cl_delegations);
-		nfsi->delegation = delegation;
+	if (rcu_dereference(nfsi->delegation) == NULL) {
+		list_add_rcu(&delegation->super_list, &clp->cl_delegations);
 		nfsi->delegation_state = delegation->type;
+		rcu_assign_pointer(nfsi->delegation, delegation);
 		delegation = NULL;
 	} else {
 		if (memcmp(&delegation->stateid, &nfsi->delegation->stateid,
@@ -145,6 +150,12 @@ int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct
 			status = -EIO;
 		}
 	}
+
+	/* Ensure we revalidate the attributes and page cache! */
+	spin_lock(&inode->i_lock);
+	nfsi->cache_validity |= NFS_INO_REVAL_FORCED;
+	spin_unlock(&inode->i_lock);
+
 	spin_unlock(&clp->cl_lock);
 	kfree(delegation);
 	return status;
@@ -155,7 +166,7 @@ static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *
 	int res = 0;
 
 	res = nfs4_proc_delegreturn(inode, delegation->cred, &delegation->stateid);
-	nfs_free_delegation(delegation);
+	call_rcu(&delegation->rcu, nfs_free_delegation_callback);
 	return res;
 }
 
@@ -170,33 +181,55 @@ static void nfs_msync_inode(struct inode *inode)
 /*
  * Basic procedure for returning a delegation to the server
  */
-int __nfs_inode_return_delegation(struct inode *inode)
+static int __nfs_inode_return_delegation(struct inode *inode, struct nfs_delegation *delegation)
 {
 	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 	struct nfs_inode *nfsi = NFS_I(inode);
-	struct nfs_delegation *delegation;
-	int res = 0;
 
 	nfs_msync_inode(inode);
 	down_read(&clp->cl_sem);
 	/* Guard against new delegated open calls */
 	down_write(&nfsi->rwsem);
-	spin_lock(&clp->cl_lock);
-	delegation = nfsi->delegation;
-	if (delegation != NULL) {
-		list_del_init(&delegation->super_list);
-		nfsi->delegation = NULL;
-		nfsi->delegation_state = 0;
-	}
-	spin_unlock(&clp->cl_lock);
-	nfs_delegation_claim_opens(inode);
+	nfs_delegation_claim_opens(inode, &delegation->stateid);
 	up_write(&nfsi->rwsem);
 	up_read(&clp->cl_sem);
 	nfs_msync_inode(inode);
 
-	if (delegation != NULL)
-		res = nfs_do_return_delegation(inode, delegation);
-	return res;
+	return nfs_do_return_delegation(inode, delegation);
+}
+
+static struct nfs_delegation *nfs_detach_delegation_locked(struct nfs_inode *nfsi, const nfs4_stateid *stateid)
+{
+	struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);
+
+	if (delegation == NULL)
+		goto nomatch;
+	if (stateid != NULL && memcmp(delegation->stateid.data, stateid->data,
+				sizeof(delegation->stateid.data)) != 0)
+		goto nomatch;
+	list_del_rcu(&delegation->super_list);
+	nfsi->delegation_state = 0;
+	rcu_assign_pointer(nfsi->delegation, NULL);
+	return delegation;
+nomatch:
+	return NULL;
+}
+
+int nfs_inode_return_delegation(struct inode *inode)
+{
+	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
+	struct nfs_inode *nfsi = NFS_I(inode);
+	struct nfs_delegation *delegation;
+	int err = 0;
+
+	if (rcu_dereference(nfsi->delegation) != NULL) {
+		spin_lock(&clp->cl_lock);
+		delegation = nfs_detach_delegation_locked(nfsi, NULL);
+		spin_unlock(&clp->cl_lock);
+		if (delegation != NULL)
+			err = __nfs_inode_return_delegation(inode, delegation);
+	}
+	return err;
 }
 
 /*
@@ -211,19 +244,23 @@ void nfs_return_all_delegations(struct super_block *sb)
 	if (clp == NULL)
 		return;
 restart:
-	spin_lock(&clp->cl_lock);
-	list_for_each_entry(delegation, &clp->cl_delegations, super_list) {
+	rcu_read_lock();
+	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 		if (delegation->inode->i_sb != sb)
 			continue;
 		inode = igrab(delegation->inode);
 		if (inode == NULL)
 			continue;
+		spin_lock(&clp->cl_lock);
+		delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
 		spin_unlock(&clp->cl_lock);
-		nfs_inode_return_delegation(inode);
+		rcu_read_unlock();
+		if (delegation != NULL)
+			__nfs_inode_return_delegation(inode, delegation);
 		iput(inode);
 		goto restart;
 	}
-	spin_unlock(&clp->cl_lock);
+	rcu_read_unlock();
 }
 
 static int nfs_do_expire_all_delegations(void *ptr)
@@ -234,22 +271,26 @@ static int nfs_do_expire_all_delegations(void *ptr)
 
 	allow_signal(SIGKILL);
 restart:
-	spin_lock(&clp->cl_lock);
 	if (test_bit(NFS4CLNT_STATE_RECOVER, &clp->cl_state) != 0)
 		goto out;
 	if (test_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state) == 0)
 		goto out;
-	list_for_each_entry(delegation, &clp->cl_delegations, super_list) {
+	rcu_read_lock();
+	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 		inode = igrab(delegation->inode);
 		if (inode == NULL)
 			continue;
+		spin_lock(&clp->cl_lock);
+		delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
 		spin_unlock(&clp->cl_lock);
-		nfs_inode_return_delegation(inode);
+		rcu_read_unlock();
+		if (delegation)
+			__nfs_inode_return_delegation(inode, delegation);
 		iput(inode);
 		goto restart;
 	}
+	rcu_read_unlock();
 out:
-	spin_unlock(&clp->cl_lock);
 	nfs_put_client(clp);
 	module_put_and_exit(0);
 }
@@ -280,17 +321,21 @@ void nfs_handle_cb_pathdown(struct nfs_client *clp)
 	if (clp == NULL)
 		return;
 restart:
-	spin_lock(&clp->cl_lock);
-	list_for_each_entry(delegation, &clp->cl_delegations, super_list) {
+	rcu_read_lock();
+	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 		inode = igrab(delegation->inode);
 		if (inode == NULL)
 			continue;
+		spin_lock(&clp->cl_lock);
+		delegation = nfs_detach_delegation_locked(NFS_I(inode), NULL);
 		spin_unlock(&clp->cl_lock);
-		nfs_inode_return_delegation(inode);
+		rcu_read_unlock();
+		if (delegation != NULL)
+			__nfs_inode_return_delegation(inode, delegation);
 		iput(inode);
 		goto restart;
 	}
-	spin_unlock(&clp->cl_lock);
+	rcu_read_unlock();
 }
 
 struct recall_threadargs {
@@ -316,21 +361,14 @@ static int recall_thread(void *data)
 	down_read(&clp->cl_sem);
 	down_write(&nfsi->rwsem);
 	spin_lock(&clp->cl_lock);
-	delegation = nfsi->delegation;
-	if (delegation != NULL && memcmp(delegation->stateid.data,
-				args->stateid->data,
-				sizeof(delegation->stateid.data)) == 0) {
-		list_del_init(&delegation->super_list);
-		nfsi->delegation = NULL;
-		nfsi->delegation_state = 0;
+	delegation = nfs_detach_delegation_locked(nfsi, args->stateid);
+	if (delegation != NULL)
 		args->result = 0;
-	} else {
-		delegation = NULL;
+	else
 		args->result = -ENOENT;
-	}
 	spin_unlock(&clp->cl_lock);
 	complete(&args->started);
-	nfs_delegation_claim_opens(inode);
+	nfs_delegation_claim_opens(inode, args->stateid);
 	up_write(&nfsi->rwsem);
 	up_read(&clp->cl_sem);
 	nfs_msync_inode(inode);
@@ -371,14 +409,14 @@ struct inode *nfs_delegation_find_inode(struct nfs_client *clp, const struct nfs
 {
 	struct nfs_delegation *delegation;
 	struct inode *res = NULL;
-	spin_lock(&clp->cl_lock);
-	list_for_each_entry(delegation, &clp->cl_delegations, super_list) {
+	rcu_read_lock();
+	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 		if (nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
 			res = igrab(delegation->inode);
 			break;
 		}
 	}
-	spin_unlock(&clp->cl_lock);
+	rcu_read_unlock();
 	return res;
 }
 
@@ -388,10 +426,10 @@ struct inode *nfs_delegation_find_inode(struct nfs_client *clp, const struct nfs
 void nfs_delegation_mark_reclaim(struct nfs_client *clp)
 {
 	struct nfs_delegation *delegation;
-	spin_lock(&clp->cl_lock);
-	list_for_each_entry(delegation, &clp->cl_delegations, super_list)
+	rcu_read_lock();
+	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list)
 		delegation->flags |= NFS_DELEGATION_NEED_RECLAIM;
-	spin_unlock(&clp->cl_lock);
+	rcu_read_unlock();
 }
 
 /*
@@ -399,39 +437,35 @@ void nfs_delegation_mark_reclaim(struct nfs_client *clp)
  */
 void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
 {
-	struct nfs_delegation *delegation, *n;
-	LIST_HEAD(head);
-	spin_lock(&clp->cl_lock);
-	list_for_each_entry_safe(delegation, n, &clp->cl_delegations, super_list) {
+	struct nfs_delegation *delegation;
+restart:
+	rcu_read_lock();
+	list_for_each_entry_rcu(delegation, &clp->cl_delegations, super_list) {
 		if ((delegation->flags & NFS_DELEGATION_NEED_RECLAIM) == 0)
 			continue;
-		list_move(&delegation->super_list, &head);
-		NFS_I(delegation->inode)->delegation = NULL;
-		NFS_I(delegation->inode)->delegation_state = 0;
-	}
-	spin_unlock(&clp->cl_lock);
-	while(!list_empty(&head)) {
-		delegation = list_entry(head.next, struct nfs_delegation, super_list);
-		list_del(&delegation->super_list);
-		nfs_free_delegation(delegation);
+		spin_lock(&clp->cl_lock);
+		delegation = nfs_detach_delegation_locked(NFS_I(delegation->inode), NULL);
+		spin_unlock(&clp->cl_lock);
+		rcu_read_unlock();
+		if (delegation != NULL)
+			call_rcu(&delegation->rcu, nfs_free_delegation_callback);
+		goto restart;
 	}
+	rcu_read_unlock();
 }
 
 int nfs4_copy_delegation_stateid(nfs4_stateid *dst, struct inode *inode)
 {
-	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 	struct nfs_inode *nfsi = NFS_I(inode);
 	struct nfs_delegation *delegation;
-	int res = 0;
+	int ret = 0;
 
-	if (nfsi->delegation_state == 0)
-		return 0;
-	spin_lock(&clp->cl_lock);
-	delegation = nfsi->delegation;
+	rcu_read_lock();
+	delegation = rcu_dereference(nfsi->delegation);
 	if (delegation != NULL) {
 		memcpy(dst->data, delegation->stateid.data, sizeof(dst->data));
-		res = 1;
+		ret = 1;
 	}
-	spin_unlock(&clp->cl_lock);
-	return res;
+	rcu_read_unlock();
+	return ret;
 }