afs: Lay the groundwork for supporting network namespaces

Lay the groundwork for supporting network namespaces (netns) to the AFS
filesystem by moving various global features to a network-namespace struct
(afs_net) and providing an instance of this as a temporary global variable
that everything uses via accessor functions for the moment.

The following changes have been made:

 (1) Store the netns in the superblock info.  This will be obtained from
     the mounter's nsproxy on a manual mount and inherited from the parent
     superblock on an automount.

 (2) The cell list is made per-netns.  It can be viewed through
     /proc/net/afs/cells and also be modified by writing commands to that
     file.

 (3) The local workstation cell is set per-ns in /proc/net/afs/rootcell.
     This is unset by default.

 (4) The 'rootcell' module parameter, which sets a cell and VL server list
     modifies the init net namespace, thereby allowing an AFS root fs to be
     theoretically used.

 (5) The volume location lists and the file lock manager are made
     per-netns.

 (6) The AF_RXRPC socket and associated I/O bits are made per-ns.

The various workqueues remain global for the moment.

Changes still to be made:

 (1) /proc/fs/afs/ should be moved to /proc/net/afs/ and a symlink emplaced
     from the old name.

 (2) A per-netns subsys needs to be registered for AFS into which it can
     store its per-netns data.

 (3) Rather than the AF_RXRPC socket being opened on module init, it needs
     to be opened on the creation of a superblock in that netns.

 (4) The socket needs to be closed when the last superblock using it is
     destroyed and all outstanding client calls on it have been completed.
     This prevents a reference loop on the namespace.

 (5) It is possible that several namespaces will want to use AFS, in which
     case each one will need its own UDP port.  These can either be set
     through /proc/net/afs/cm_port or the kernel can pick one at random.
     The init_ns gets 7001 by default.

Other issues that need resolving:

 (1) The DNS keyring needs net-namespacing.

 (2) Where do upcalls go (eg. DNS request-key upcall)?

 (3) Need something like open_socket_in_file_ns() syscall so that AFS
     command line tools attempting to operate on an AFS file/volume have
     their RPC calls go to the right place.

Signed-off-by: David Howells <dhowells@redhat.com>

1 files changed, 105 insertions, 48 deletions

diff --git a/fs/afs/main.c b/fs/afs/main.c
index 9944770849da..87b1a9c8000d 100644
--- a/fs/afs/main.c
+++ b/fs/afs/main.c
@@ -31,30 +31,104 @@ static char *rootcell;
 module_param(rootcell, charp, 0);
 MODULE_PARM_DESC(rootcell, "root AFS cell name and VL server IP addr list");
 
-struct afs_uuid afs_uuid;
 struct workqueue_struct *afs_wq;
+struct afs_net __afs_net;
+
+/*
+ * Initialise an AFS network namespace record.
+ */
+static int __net_init afs_net_init(struct afs_net *net)
+{
+	int ret;
+
+	net->live = true;
+	generate_random_uuid((unsigned char *)&net->uuid);
+
+	INIT_WORK(&net->charge_preallocation_work, afs_charge_preallocation);
+	mutex_init(&net->socket_mutex);
+	INIT_LIST_HEAD(&net->cells);
+	rwlock_init(&net->cells_lock);
+	init_rwsem(&net->cells_sem);
+	init_waitqueue_head(&net->cells_freeable_wq);
+	init_rwsem(&net->proc_cells_sem);
+	INIT_LIST_HEAD(&net->proc_cells);
+	INIT_LIST_HEAD(&net->vl_updates);
+	INIT_LIST_HEAD(&net->vl_graveyard);
+	INIT_DELAYED_WORK(&net->vl_reaper, afs_vlocation_reaper);
+	INIT_DELAYED_WORK(&net->vl_updater, afs_vlocation_updater);
+	spin_lock_init(&net->vl_updates_lock);
+	spin_lock_init(&net->vl_graveyard_lock);
+	net->servers = RB_ROOT;
+	rwlock_init(&net->servers_lock);
+	INIT_LIST_HEAD(&net->server_graveyard);
+	spin_lock_init(&net->server_graveyard_lock);
+	INIT_DELAYED_WORK(&net->server_reaper, afs_reap_server);
+
+	/* Register the /proc stuff */
+	ret = afs_proc_init(net);
+	if (ret < 0)
+		goto error_proc;
+
+	/* Initialise the cell DB */
+	ret = afs_cell_init(net, rootcell);
+	if (ret < 0)
+		goto error_cell_init;
+
+	/* Create the RxRPC transport */
+	ret = afs_open_socket(net);
+	if (ret < 0)
+		goto error_open_socket;
+
+	return 0;
+
+error_open_socket:
+	afs_vlocation_purge(net);
+	afs_cell_purge(net);
+error_cell_init:
+	afs_proc_cleanup(net);
+error_proc:
+	return ret;
+}
+
+/*
+ * Clean up and destroy an AFS network namespace record.
+ */
+static void __net_exit afs_net_exit(struct afs_net *net)
+{
+	net->live = false;
+	afs_close_socket(net);
+	afs_purge_servers(net);
+	afs_vlocation_purge(net);
+	afs_cell_purge(net);
+	afs_proc_cleanup(net);
+}
 
 /*
  * initialise the AFS client FS module
  */
 static int __init afs_init(void)
 {
-	int ret;
+	int ret = -ENOMEM;
 
 	printk(KERN_INFO "kAFS: Red Hat AFS client v0.1 registering.\n");
 
-	generate_random_uuid((unsigned char *)&afs_uuid);
-
-	/* create workqueue */
-	ret = -ENOMEM;
 	afs_wq = alloc_workqueue("afs", 0, 0);
 	if (!afs_wq)
-		return ret;
-
-	/* register the /proc stuff */
-	ret = afs_proc_init();
-	if (ret < 0)
-		goto error_proc;
+		goto error_afs_wq;
+	afs_async_calls = alloc_workqueue("kafsd", WQ_MEM_RECLAIM, 0);
+	if (!afs_async_calls)
+		goto error_async;
+	afs_vlocation_update_worker =
+		alloc_workqueue("kafs_vlupdated", WQ_MEM_RECLAIM, 0);
+	if (!afs_vlocation_update_worker)
+		goto error_vl_up;
+	afs_callback_update_worker =
+		alloc_ordered_workqueue("kafs_callbackd", WQ_MEM_RECLAIM);
+	if (!afs_callback_update_worker)
+		goto error_callback;
+	afs_lock_manager = alloc_workqueue("kafs_lockd", WQ_MEM_RECLAIM, 0);
+	if (!afs_lock_manager)
+		goto error_lockmgr;
 
 #ifdef CONFIG_AFS_FSCACHE
 	/* we want to be able to cache */
@@ -63,25 +137,9 @@ static int __init afs_init(void)
 		goto error_cache;
 #endif
 
-	/* initialise the cell DB */
-	ret = afs_cell_init(rootcell);
-	if (ret < 0)
-		goto error_cell_init;
-
-	/* initialise the VL update process */
-	ret = afs_vlocation_update_init();
-	if (ret < 0)
-		goto error_vl_update_init;
-
-	/* initialise the callback update process */
-	ret = afs_callback_update_init();
+	ret = afs_net_init(&__afs_net);
 	if (ret < 0)
-		goto error_callback_update_init;
-
-	/* create the RxRPC transport */
-	ret = afs_open_socket();
-	if (ret < 0)
-		goto error_open_socket;
+		goto error_net;
 
 	/* register the filesystems */
 	ret = afs_fs_init();
@@ -91,21 +149,22 @@ static int __init afs_init(void)
 	return ret;
 
 error_fs:
-	afs_close_socket();
-error_open_socket:
-	afs_callback_update_kill();
-error_callback_update_init:
-	afs_vlocation_purge();
-error_vl_update_init:
-	afs_cell_purge();
-error_cell_init:
+	afs_net_exit(&__afs_net);
+error_net:
 #ifdef CONFIG_AFS_FSCACHE
 	fscache_unregister_netfs(&afs_cache_netfs);
 error_cache:
 #endif
-	afs_proc_cleanup();
-error_proc:
+	destroy_workqueue(afs_lock_manager);
+error_lockmgr:
+	destroy_workqueue(afs_callback_update_worker);
+error_callback:
+	destroy_workqueue(afs_vlocation_update_worker);
+error_vl_up:
+	destroy_workqueue(afs_async_calls);
+error_async:
 	destroy_workqueue(afs_wq);
+error_afs_wq:
 	rcu_barrier();
 	printk(KERN_ERR "kAFS: failed to register: %d\n", ret);
 	return ret;
@@ -124,17 +183,15 @@ static void __exit afs_exit(void)
 	printk(KERN_INFO "kAFS: Red Hat AFS client v0.1 unregistering.\n");
 
 	afs_fs_exit();
-	afs_kill_lock_manager();
-	afs_close_socket();
-	afs_purge_servers();
-	afs_callback_update_kill();
-	afs_vlocation_purge();
-	destroy_workqueue(afs_wq);
-	afs_cell_purge();
+	afs_net_exit(&__afs_net);
 #ifdef CONFIG_AFS_FSCACHE
 	fscache_unregister_netfs(&afs_cache_netfs);
 #endif
-	afs_proc_cleanup();
+	destroy_workqueue(afs_lock_manager);
+	destroy_workqueue(afs_callback_update_worker);
+	destroy_workqueue(afs_vlocation_update_worker);
+	destroy_workqueue(afs_async_calls);
+	destroy_workqueue(afs_wq);
 	rcu_barrier();
 }