NFS: release per-net clients lock before calling PipeFS dentries creation

v3: 1) Lookup for client is performed from the beginning of the list on each PipeFS event handling operation. Lockdep is sad otherwise, because inode mutex is taken on PipeFS dentry creation, which can be called on mount notification, where this per-net client lock is taken on clients list walk. Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

NFS: release per-net clients lock before calling PipeFS dentries creation
v3: 1) Lookup for client is performed from the beginning of the list on each PipeFS event handling operation. Lockdep is sad otherwise, because inode mutex is taken on PipeFS dentry creation, which can be called on mount notification, where this per-net client lock is taken on clients list walk. Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Stanislav Kinsbursky · Trond Myklebust
1 parent da3b462296
Showing 1 changed file with 24 additions and 6 deletions Side-by-side Diff
fs/nfs/idmap.c
@@ -553,23 +553,41 @@
 	return err;
 }
  
-static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event,
-			    void *ptr)
+static struct nfs_client *nfs_get_client_for_event(struct net *net, int event)
 {
-	struct super_block *sb = ptr;
-	struct nfs_net *nn = net_generic(sb->s_fs_info, nfs_net_id);
+	struct nfs_net *nn = net_generic(net, nfs_net_id);
+	struct dentry *cl_dentry;
 	struct nfs_client *clp;
-	int error = 0;
  
 	spin_lock(&nn->nfs_client_lock);
 	list_for_each_entry(clp, &nn->nfs_client_list, cl_share_link) {
 		if (clp->rpc_ops != &nfs_v4_clientops)
 			continue;
+		cl_dentry = clp->cl_idmap->idmap_pipe->dentry;
+		if (((event == RPC_PIPEFS_MOUNT) && cl_dentry) ||
+		    ((event == RPC_PIPEFS_UMOUNT) && !cl_dentry))
+			continue;
+		atomic_inc(&clp->cl_count);
+		spin_unlock(&nn->nfs_client_lock);
+		return clp;
+	}
+	spin_unlock(&nn->nfs_client_lock);
+	return NULL;
+}
+
+static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event,
+			    void *ptr)
+{
+	struct super_block *sb = ptr;
+	struct nfs_client *clp;
+	int error = 0;
+
+	while ((clp = nfs_get_client_for_event(sb->s_fs_info, event))) {
 		error = __rpc_pipefs_event(clp, event, sb);
+		nfs_put_client(clp);
 		if (error)
 			break;
 	}
-	spin_unlock(&nn->nfs_client_lock);
 	return error;
 }
...	...	@@ -553,23 +553,41 @@
553	553	return err;
554	554	}
555	555
556		-static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event,
557		- void *ptr)
	556	+static struct nfs_client nfs_get_client_for_event(struct net net, int event)
558	557	{
559		- struct super_block *sb = ptr;
560		- struct nfs_net *nn = net_generic(sb->s_fs_info, nfs_net_id);
	558	+ struct nfs_net *nn = net_generic(net, nfs_net_id);
	559	+ struct dentry *cl_dentry;
561	560	struct nfs_client *clp;
562		- int error = 0;
563	561
564	562	spin_lock(&nn->nfs_client_lock);
565	563	list_for_each_entry(clp, &nn->nfs_client_list, cl_share_link) {
566	564	if (clp->rpc_ops != &nfs_v4_clientops)
567	565	continue;
	566	+ cl_dentry = clp->cl_idmap->idmap_pipe->dentry;
	567	+ if (((event == RPC_PIPEFS_MOUNT) && cl_dentry) \|\|
	568	+ ((event == RPC_PIPEFS_UMOUNT) && !cl_dentry))
	569	+ continue;
	570	+ atomic_inc(&clp->cl_count);
	571	+ spin_unlock(&nn->nfs_client_lock);
	572	+ return clp;
	573	+ }
	574	+ spin_unlock(&nn->nfs_client_lock);
	575	+ return NULL;
	576	+}
	577	+
	578	+static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event,
	579	+ void *ptr)
	580	+{
	581	+ struct super_block *sb = ptr;
	582	+ struct nfs_client *clp;
	583	+ int error = 0;
	584	+
	585	+ while ((clp = nfs_get_client_for_event(sb->s_fs_info, event))) {
568	586	error = __rpc_pipefs_event(clp, event, sb);
	587	+ nfs_put_client(clp);
569	588	if (error)
570	589	break;
571	590	}
572		- spin_unlock(&nn->nfs_client_lock);
573	591	return error;
574	592	}
575	593