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, 122 insertions, 41 deletions

diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index 3f03f7888302..53bd11d73469 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -21,6 +21,7 @@
 #include <linux/fscache.h>
 #include <linux/backing-dev.h>
 #include <linux/uuid.h>
+#include <net/net_namespace.h>
 #include <net/af_rxrpc.h>
 
 #include "afs.h"
@@ -48,6 +49,7 @@ struct afs_mount_params {
 	afs_voltype_t		type;		/* type of volume requested */
 	int			volnamesz;	/* size of volume name */
 	const char		*volname;	/* name of volume to mount */
+	struct afs_net		*net;		/* Network namespace in effect */
 	struct afs_cell		*cell;		/* cell in which to find volume */
 	struct afs_volume	*volume;	/* volume record */
 	struct key		*key;		/* key to use for secure mounting */
@@ -62,6 +64,7 @@ enum afs_call_state {
 	AFS_CALL_AWAIT_ACK,	/* awaiting final ACK of incoming call */
 	AFS_CALL_COMPLETE,	/* Completed or failed */
 };
+
 /*
  * a record of an in-progress RxRPC call
  */
@@ -72,6 +75,7 @@ struct afs_call {
 	struct work_struct	work;		/* actual work processor */
 	struct rxrpc_call	*rxcall;	/* RxRPC call handle */
 	struct key		*key;		/* security for this call */
+	struct afs_net		*net;		/* The network namespace */
 	struct afs_server	*server;	/* server affected by incoming CM call */
 	void			*request;	/* request data (first part) */
 	struct address_space	*mapping;	/* page set */
@@ -173,6 +177,7 @@ struct afs_writeback {
  * - there's one superblock per volume
  */
 struct afs_super_info {
+	struct afs_net		*net;		/* Network namespace */
 	struct afs_volume	*volume;	/* volume record */
 	char			rwparent;	/* T if parent is R/W AFS volume */
 };
@@ -193,11 +198,61 @@ struct afs_cache_cell {
 };
 
 /*
+ * AFS network namespace record.
+ */
+struct afs_net {
+	struct afs_uuid		uuid;
+	bool			live;		/* F if this namespace is being removed */
+
+	/* AF_RXRPC I/O stuff */
+	struct socket		*socket;
+	struct afs_call		*spare_incoming_call;
+	struct work_struct	charge_preallocation_work;
+	struct mutex		socket_mutex;
+	atomic_t		nr_outstanding_calls;
+	atomic_t		nr_superblocks;
+
+	/* Cell database */
+	struct list_head	cells;
+	struct afs_cell		*ws_cell;
+	rwlock_t		cells_lock;
+	struct rw_semaphore	cells_sem;
+	wait_queue_head_t	cells_freeable_wq;
+
+	struct rw_semaphore	proc_cells_sem;
+	struct list_head	proc_cells;
+
+	/* Volume location database */
+	struct list_head	vl_updates;		/* VL records in need-update order */
+	struct list_head	vl_graveyard;		/* Inactive VL records */
+	struct delayed_work	vl_reaper;
+	struct delayed_work	vl_updater;
+	spinlock_t		vl_updates_lock;
+	spinlock_t		vl_graveyard_lock;
+
+	/* File locking renewal management */
+	struct mutex		lock_manager_mutex;
+
+	/* Server database */
+	struct rb_root		servers;		/* Active servers */
+	rwlock_t		servers_lock;
+	struct list_head	server_graveyard;	/* Inactive server LRU list */
+	spinlock_t		server_graveyard_lock;
+	struct delayed_work	server_reaper;
+
+	/* Misc */
+	struct proc_dir_entry	*proc_afs;		/* /proc/net/afs directory */
+};
+
+extern struct afs_net __afs_net;// Dummy AFS network namespace; TODO: replace with real netns
+
+/*
  * AFS cell record
  */
 struct afs_cell {
 	atomic_t		usage;
 	struct list_head	link;		/* main cell list link */
+	struct afs_net		*net;		/* The network namespace */
 	struct key		*anonymous_key;	/* anonymous user key for this cell */
 	struct list_head	proc_link;	/* /proc cell list link */
 #ifdef CONFIG_AFS_FSCACHE
@@ -411,15 +466,6 @@ struct afs_interface {
 	unsigned	mtu;		/* MTU of interface */
 };
 
-struct afs_uuid {
-	__be32		time_low;			/* low part of timestamp */
-	__be16		time_mid;			/* mid part of timestamp */
-	__be16		time_hi_and_version;		/* high part of timestamp and version  */
-	__u8		clock_seq_hi_and_reserved;	/* clock seq hi and variant */
-	__u8		clock_seq_low;			/* clock seq low */
-	__u8		node[6];			/* spatially unique node ID (MAC addr) */
-};
-
 /*****************************************************************************/
 /*
  * cache.c
@@ -440,6 +486,8 @@ extern struct fscache_cookie_def afs_vnode_cache_index_def;
 /*
  * callback.c
  */
+extern struct workqueue_struct *afs_callback_update_worker;
+
 extern void afs_init_callback_state(struct afs_server *);
 extern void afs_broken_callback_work(struct work_struct *);
 extern void afs_break_callbacks(struct afs_server *, size_t,
@@ -448,22 +496,17 @@ extern void afs_discard_callback_on_delete(struct afs_vnode *);
 extern void afs_give_up_callback(struct afs_vnode *);
 extern void afs_dispatch_give_up_callbacks(struct work_struct *);
 extern void afs_flush_callback_breaks(struct afs_server *);
-extern int __init afs_callback_update_init(void);
-extern void afs_callback_update_kill(void);
 
 /*
  * cell.c
  */
-extern struct rw_semaphore afs_proc_cells_sem;
-extern struct list_head afs_proc_cells;
-
 #define afs_get_cell(C) do { atomic_inc(&(C)->usage); } while(0)
-extern int afs_cell_init(char *);
-extern struct afs_cell *afs_cell_create(const char *, unsigned, char *, bool);
-extern struct afs_cell *afs_cell_lookup(const char *, unsigned, bool);
+extern int afs_cell_init(struct afs_net *, char *);
+extern struct afs_cell *afs_cell_create(struct afs_net *, const char *, unsigned, char *, bool);
+extern struct afs_cell *afs_cell_lookup(struct afs_net *, const char *, unsigned, bool);
 extern struct afs_cell *afs_grab_cell(struct afs_cell *);
 extern void afs_put_cell(struct afs_cell *);
-extern void afs_cell_purge(void);
+extern void __net_exit afs_cell_purge(struct afs_net *);
 
 /*
  * cmservice.c
@@ -492,7 +535,8 @@ extern void afs_put_read(struct afs_read *);
 /*
  * flock.c
  */
-extern void __exit afs_kill_lock_manager(void);
+extern struct workqueue_struct *afs_lock_manager;
+
 extern void afs_lock_work(struct work_struct *);
 extern void afs_lock_may_be_available(struct afs_vnode *);
 extern int afs_lock(struct file *, int, struct file_lock *);
@@ -504,7 +548,7 @@ extern int afs_flock(struct file *, int, struct file_lock *);
 extern int afs_fs_fetch_file_status(struct afs_server *, struct key *,
 				    struct afs_vnode *, struct afs_volsync *,
 				    bool);
-extern int afs_fs_give_up_callbacks(struct afs_server *, bool);
+extern int afs_fs_give_up_callbacks(struct afs_net *, struct afs_server *, bool);
 extern int afs_fs_fetch_data(struct afs_server *, struct key *,
 			     struct afs_vnode *, struct afs_read *, bool);
 extern int afs_fs_create(struct afs_server *, struct key *,
@@ -554,7 +598,35 @@ extern int afs_drop_inode(struct inode *);
  * main.c
  */
 extern struct workqueue_struct *afs_wq;
-extern struct afs_uuid afs_uuid;
+
+static inline struct afs_net *afs_d2net(struct dentry *dentry)
+{
+	return &__afs_net;
+}
+
+static inline struct afs_net *afs_i2net(struct inode *inode)
+{
+	return &__afs_net;
+}
+
+static inline struct afs_net *afs_v2net(struct afs_vnode *vnode)
+{
+	return &__afs_net;
+}
+
+static inline struct afs_net *afs_sock2net(struct sock *sk)
+{
+	return &__afs_net;
+}
+
+static inline struct afs_net *afs_get_net(struct afs_net *net)
+{
+	return net;
+}
+
+static inline void afs_put_net(struct afs_net *net)
+{
+}
 
 /*
  * misc.c
@@ -579,23 +651,24 @@ extern int afs_get_ipv4_interfaces(struct afs_interface *, size_t, bool);
 /*
  * proc.c
  */
-extern int afs_proc_init(void);
-extern void afs_proc_cleanup(void);
-extern int afs_proc_cell_setup(struct afs_cell *);
-extern void afs_proc_cell_remove(struct afs_cell *);
+extern int __net_init afs_proc_init(struct afs_net *);
+extern void __net_exit afs_proc_cleanup(struct afs_net *);
+extern int afs_proc_cell_setup(struct afs_net *, struct afs_cell *);
+extern void afs_proc_cell_remove(struct afs_net *, struct afs_cell *);
 
 /*
  * rxrpc.c
  */
-extern struct socket *afs_socket;
-extern atomic_t afs_outstanding_calls;
+extern struct workqueue_struct *afs_async_calls;
 
-extern int afs_open_socket(void);
-extern void afs_close_socket(void);
+extern int __net_init afs_open_socket(struct afs_net *);
+extern void __net_exit afs_close_socket(struct afs_net *);
+extern void afs_charge_preallocation(struct work_struct *);
 extern void afs_put_call(struct afs_call *);
 extern int afs_queue_call_work(struct afs_call *);
 extern int afs_make_call(struct in_addr *, struct afs_call *, gfp_t, bool);
-extern struct afs_call *afs_alloc_flat_call(const struct afs_call_type *,
+extern struct afs_call *afs_alloc_flat_call(struct afs_net *,
+					    const struct afs_call_type *,
 					    size_t, size_t);
 extern void afs_flat_call_destructor(struct afs_call *);
 extern void afs_send_empty_reply(struct afs_call *);
@@ -629,37 +702,45 @@ do {								\
 
 extern struct afs_server *afs_lookup_server(struct afs_cell *,
 					    const struct in_addr *);
-extern struct afs_server *afs_find_server(const struct sockaddr_rxrpc *);
+extern struct afs_server *afs_find_server(struct afs_net *,
+					  const struct sockaddr_rxrpc *);
 extern void afs_put_server(struct afs_server *);
-extern void __exit afs_purge_servers(void);
+extern void afs_reap_server(struct work_struct *);
+extern void __net_exit afs_purge_servers(struct afs_net *);
 
 /*
  * super.c
  */
-extern int afs_fs_init(void);
-extern void afs_fs_exit(void);
+extern int __init afs_fs_init(void);
+extern void __exit afs_fs_exit(void);
 
 /*
  * vlclient.c
  */
-extern int afs_vl_get_entry_by_name(struct in_addr *, struct key *,
+extern int afs_vl_get_entry_by_name(struct afs_net *,
+				    struct in_addr *, struct key *,
 				    const char *, struct afs_cache_vlocation *,
 				    bool);
-extern int afs_vl_get_entry_by_id(struct in_addr *, struct key *,
+extern int afs_vl_get_entry_by_id(struct afs_net *,
+				  struct in_addr *, struct key *,
 				  afs_volid_t, afs_voltype_t,
 				  struct afs_cache_vlocation *, bool);
 
 /*
  * vlocation.c
  */
+extern struct workqueue_struct *afs_vlocation_update_worker;
+
 #define afs_get_vlocation(V) do { atomic_inc(&(V)->usage); } while(0)
 
-extern int __init afs_vlocation_update_init(void);
-extern struct afs_vlocation *afs_vlocation_lookup(struct afs_cell *,
+extern struct afs_vlocation *afs_vlocation_lookup(struct afs_net *,
+						  struct afs_cell *,
 						  struct key *,
 						  const char *, size_t);
-extern void afs_put_vlocation(struct afs_vlocation *);
-extern void afs_vlocation_purge(void);
+extern void afs_put_vlocation(struct afs_net *, struct afs_vlocation *);
+extern void afs_vlocation_updater(struct work_struct *);
+extern void afs_vlocation_reaper(struct work_struct *);
+extern void __net_exit afs_vlocation_purge(struct afs_net *);
 
 /*
  * vnode.c
@@ -707,7 +788,7 @@ extern int afs_vnode_release_lock(struct afs_vnode *, struct key *);
  */
 #define afs_get_volume(V) do { atomic_inc(&(V)->usage); } while(0)
 
-extern void afs_put_volume(struct afs_volume *);
+extern void afs_put_volume(struct afs_net *, struct afs_volume *);
 extern struct afs_volume *afs_volume_lookup(struct afs_mount_params *);
 extern struct afs_server *afs_volume_pick_fileserver(struct afs_vnode *);
 extern int afs_volume_release_fileserver(struct afs_vnode *,