afs: Overhaul volume and server record caching and fileserver rotation

The current code assumes that volumes and servers are per-cell and are
never shared, but this is not enforced, and, indeed, public cells do exist
that are aliases of each other.  Further, an organisation can, say, set up
a public cell and a private cell with overlapping, but not identical, sets
of servers.  The difference is purely in the database attached to the VL
servers.

The current code will malfunction if it sees a server in two cells as it
assumes global address -> server record mappings and that each server is in
just one cell.

Further, each server may have multiple addresses - and may have addresses
of different families (IPv4 and IPv6, say).

To this end, the following structural changes are made:

 (1) Server record management is overhauled:

     (a) Server records are made independent of cell.  The namespace keeps
     	 track of them, volume records have lists of them and each vnode
     	 has a server on which its callback interest currently resides.

     (b) The cell record no longer keeps a list of servers known to be in
     	 that cell.

     (c) The server records are now kept in a flat list because there's no
     	 single address to sort on.

     (d) Server records are now keyed by their UUID within the namespace.

     (e) The addresses for a server are obtained with the VL.GetAddrsU
     	 rather than with VL.GetEntryByName, using the server's UUID as a
     	 parameter.

     (f) Cached server records are garbage collected after a period of
     	 non-use and are counted out of existence before purging is allowed
     	 to complete.  This protects the work functions against rmmod.

     (g) The servers list is now in /proc/fs/afs/servers.

 (2) Volume record management is overhauled:

     (a) An RCU-replaceable server list is introduced.  This tracks both
     	 servers and their coresponding callback interests.

     (b) The superblock is now keyed on cell record and numeric volume ID.

     (c) The volume record is now tied to the superblock which mounts it,
     	 and is activated when mounted and deactivated when unmounted.
     	 This makes it easier to handle the cache cookie without causing a
     	 double-use in fscache.

     (d) The volume record is loaded from the VLDB using VL.GetEntryByNameU
     	 to get the server UUID list.

     (e) The volume name is updated if it is seen to have changed when the
     	 volume is updated (the update is keyed on the volume ID).

 (3) The vlocation record is got rid of and VLDB records are no longer
     cached.  Sufficient information is stored in the volume record, though
     an update to a volume record is now no longer shared between related
     volumes (volumes come in bundles of three: R/W, R/O and backup).

and the following procedural changes are made:

 (1) The fileserver cursor introduced previously is now fleshed out and
     used to iterate over fileservers and their addresses.

 (2) Volume status is checked during iteration, and the server list is
     replaced if a change is detected.

 (3) Server status is checked during iteration, and the address list is
     replaced if a change is detected.

 (4) The abort code is saved into the address list cursor and -ECONNABORTED
     returned in afs_make_call() if a remote abort happened rather than
     translating the abort into an error message.  This allows actions to
     be taken depending on the abort code more easily.

     (a) If a VMOVED abort is seen then this is handled by rechecking the
     	 volume and restarting the iteration.

     (b) If a VBUSY, VRESTARTING or VSALVAGING abort is seen then this is
         handled by sleeping for a short period and retrying and/or trying
         other servers that might serve that volume.  A message is also
         displayed once until the condition has cleared.

     (c) If a VOFFLINE abort is seen, then this is handled as VBUSY for the
     	 moment.

     (d) If a VNOVOL abort is seen, the volume is rechecked in the VLDB to
     	 see if it has been deleted; if not, the fileserver is probably
     	 indicating that the volume couldn't be attached and needs
     	 salvaging.

     (e) If statfs() sees one of these aborts, it does not sleep, but
     	 rather returns an error, so as not to block the umount program.

 (5) The fileserver iteration functions in vnode.c are now merged into
     their callers and more heavily macroised around the cursor.  vnode.c
     is removed.

 (6) Operations on a particular vnode are serialised on that vnode because
     the server will lock that vnode whilst it operates on it, so a second
     op sent will just have to wait.

 (7) Fileservers are probed with FS.GetCapabilities before being used.
     This is where service upgrade will be done.

 (8) A callback interest on a fileserver is set up before an FS operation
     is performed and passed through to afs_make_call() so that it can be
     set on the vnode if the operation returns a callback.  The callback
     interest is passed through to afs_iget() also so that it can be set
     there too.

In general, record updating is done on an as-needed basis when we try to
access servers, volumes or vnodes rather than offloading it to work items
and special threads.

Notes:

 (1) Pre AFS-3.4 servers are no longer supported, though this can be added
     back if necessary (AFS-3.4 was released in 1998).

 (2) VBUSY is retried forever for the moment at intervals of 1s.

 (3) /proc/fs/afs/<cell>/servers no longer exists.

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

1 files changed, 235 insertions, 218 deletions

diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index df52bf18a263..1fadf40551fd 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -32,16 +32,6 @@
 struct pagevec;
 struct afs_call;
 
-typedef enum {
-	AFS_VL_NEW,			/* new, uninitialised record */
-	AFS_VL_CREATING,		/* creating record */
-	AFS_VL_VALID,			/* record is pending */
-	AFS_VL_NO_VOLUME,		/* no such volume available */
-	AFS_VL_UPDATING,		/* update in progress */
-	AFS_VL_VOLUME_DELETED,		/* volume was deleted */
-	AFS_VL_UNCERTAIN,		/* uncertain state (update failed) */
-} __attribute__((packed)) afs_vlocation_state_t;
-
 struct afs_mount_params {
 	bool			rwpath;		/* T if the parent should be considered R/W */
 	bool			force;		/* T to force cell type */
@@ -76,8 +66,10 @@ enum afs_call_state {
 struct afs_addr_list {
 	struct rcu_head		rcu;		/* Must be first */
 	refcount_t		usage;
+	u32			version;	/* Version */
 	unsigned short		nr_addrs;
 	unsigned short		index;		/* Address currently in use */
+	unsigned short		nr_ipv4;	/* Number of IPv4 addresses */
 	struct sockaddr_rxrpc	addrs[];
 };
 
@@ -93,7 +85,7 @@ struct afs_call {
 	struct key		*key;		/* security for this call */
 	struct afs_net		*net;		/* The network namespace */
 	struct afs_server	*cm_server;	/* Server affected by incoming CM call */
-	struct afs_server	*server;	/* Server used by client call */
+	struct afs_cb_interest	*cbi;		/* Callback interest for server used */
 	void			*request;	/* request data (first part) */
 	struct address_space	*mapping;	/* page set */
 	struct afs_writeback	*wb;		/* writeback being performed */
@@ -192,7 +184,6 @@ struct afs_super_info {
 	struct afs_net		*net;		/* Network namespace */
 	struct afs_cell		*cell;		/* The cell in which the volume resides */
 	struct afs_volume	*volume;	/* volume record */
-	char			rwparent;	/* T if parent is R/W AFS volume */
 };
 
 static inline struct afs_super_info *AFS_FS_S(struct super_block *sb)
@@ -228,26 +219,26 @@ struct afs_net {
 	spinlock_t		proc_cells_lock;
 	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;
+	/* Known servers.  Theoretically each fileserver can only be in one
+	 * cell, but in practice, people create aliases and subsets and there's
+	 * no easy way to distinguish them.
+	 */
+	seqlock_t		fs_lock;	/* For fs_servers */
+	struct rb_root		fs_servers;	/* afs_server (by server UUID or address) */
+	struct list_head	fs_updates;	/* afs_server (by update_at) */
+	struct hlist_head	fs_proc;	/* procfs servers list */
 
-	/* File locking renewal management */
-	struct mutex		lock_manager_mutex;
+	struct hlist_head	fs_addresses4;	/* afs_server (by lowest IPv4 addr) */
+	struct hlist_head	fs_addresses6;	/* afs_server (by lowest IPv6 addr) */
+	seqlock_t		fs_addr_lock;	/* For fs_addresses[46] */
 
-	/* 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 timer_list	server_timer;
-	struct work_struct	server_reaper;
+	struct work_struct	fs_manager;
+	struct timer_list	fs_timer;
 	atomic_t		servers_outstanding;
 
+	/* File locking renewal management */
+	struct mutex		lock_manager_mutex;
+
 	/* Misc */
 	struct proc_dir_entry	*proc_afs;		/* /proc/net/afs directory */
 };
@@ -264,7 +255,21 @@ enum afs_cell_state {
 };
 
 /*
- * AFS cell record
+ * AFS cell record.
+ *
+ * This is a tricky concept to get right as it is possible to create aliases
+ * simply by pointing AFSDB/SRV records for two names at the same set of VL
+ * servers; it is also possible to do things like setting up two sets of VL
+ * servers, one of which provides a superset of the volumes provided by the
+ * other (for internal/external division, for example).
+ *
+ * Cells only exist in the sense that (a) a cell's name maps to a set of VL
+ * servers and (b) a cell's name is used by the client to select the key to use
+ * for authentication and encryption.  The cell name is not typically used in
+ * the protocol.
+ *
+ * There is no easy way to determine if two cells are aliases or one is a
+ * subset of another.
  */
 struct afs_cell {
 	union {
@@ -278,14 +283,6 @@ struct afs_cell {
 #ifdef CONFIG_AFS_FSCACHE
 	struct fscache_cookie	*cache;		/* caching cookie */
 #endif
-
-	/* server record management */
-	rwlock_t		servers_lock;	/* active server list lock */
-	struct list_head	servers;	/* active server list */
-
-	/* volume location record management */
-	struct rw_semaphore	vl_sem;		/* volume management serialisation semaphore */
-	struct list_head	vl_list;	/* cell's active VL record list */
 	time64_t		dns_expiry;	/* Time AFSDB/SRV record expires */
 	time64_t		last_inactive;	/* Time of last drop of usage count */
 	atomic_t		usage;
@@ -298,9 +295,11 @@ struct afs_cell {
 	enum afs_cell_state	state;
 	short			error;
 
-	spinlock_t		vl_lock;	/* vl_list lock */
+	/* Active fileserver interaction state. */
+	struct list_head	proc_volumes;	/* procfs volume list */
+	rwlock_t		proc_lock;
 
-	/* VLDB server list. */
+	/* VL server list. */
 	rwlock_t		vl_addrs_lock;	/* Lock on vl_addrs */
 	struct afs_addr_list	__rcu *vl_addrs; /* List of VL servers */
 	u8			name_len;	/* Length of name */
@@ -308,65 +307,62 @@ struct afs_cell {
 };
 
 /*
- * entry in the cached volume location catalogue
+ * Cached VLDB entry.
+ *
+ * This is pointed to by cell->vldb_entries, indexed by name.
  */
-struct afs_cache_vlocation {
-	/* volume name (lowercase, padded with NULs) */
-	uint8_t			name[AFS_MAXVOLNAME + 1];
+struct afs_vldb_entry {
+	afs_volid_t		vid[3];		/* Volume IDs for R/W, R/O and Bak volumes */
 
-	uint8_t			nservers;	/* number of entries used in servers[] */
-	uint8_t			vidmask;	/* voltype mask for vid[] */
-	uint8_t			srvtmask[8];	/* voltype masks for servers[] */
+	unsigned long		flags;
+#define AFS_VLDB_HAS_RW		0		/* - R/W volume exists */
+#define AFS_VLDB_HAS_RO		1		/* - R/O volume exists */
+#define AFS_VLDB_HAS_BAK	2		/* - Backup volume exists */
+#define AFS_VLDB_QUERY_VALID	3		/* - Record is valid */
+#define AFS_VLDB_QUERY_ERROR	4		/* - VL server returned error */
+
+	uuid_t			fs_server[AFS_NMAXNSERVERS];
+	u8			fs_mask[AFS_NMAXNSERVERS];
 #define AFS_VOL_VTM_RW	0x01 /* R/W version of the volume is available (on this server) */
 #define AFS_VOL_VTM_RO	0x02 /* R/O version of the volume is available (on this server) */
 #define AFS_VOL_VTM_BAK	0x04 /* backup version of the volume is available (on this server) */
-
-	afs_volid_t		vid[3];		/* volume IDs for R/W, R/O and Bak volumes */
-	struct sockaddr_rxrpc	servers[8];	/* fileserver addresses */
-	time_t			rtime;		/* last retrieval time */
-};
-
-/*
- * AFS volume location record
- */
-struct afs_vlocation {
-	atomic_t		usage;
-	time64_t		time_of_death;	/* time at which put reduced usage to 0 */
-	struct list_head	link;		/* link in cell volume location list */
-	struct list_head	grave;		/* link in master graveyard list */
-	struct list_head	update;		/* link in master update list */
-	struct afs_cell		*cell;		/* cell to which volume belongs */
-	struct afs_cache_vlocation vldb;	/* volume information DB record */
-	struct afs_volume	*vols[3];	/* volume access record pointer (index by type) */
-	wait_queue_head_t	waitq;		/* status change waitqueue */
-	time64_t		update_at;	/* time at which record should be updated */
-	spinlock_t		lock;		/* access lock */
-	afs_vlocation_state_t	state;		/* volume location state */
-	unsigned short		upd_rej_cnt;	/* ENOMEDIUM count during update */
-	unsigned short		upd_busy_cnt;	/* EBUSY count during update */
-	bool			valid;		/* T if valid */
+	short			error;
+	u8			nr_servers;	/* Number of server records */
+	u8			name_len;
+	u8			name[AFS_MAXVOLNAME + 1]; /* NUL-padded volume name */
 };
 
 /*
- * AFS fileserver record
+ * Record of fileserver with which we're actively communicating.
  */
 struct afs_server {
-	atomic_t		usage;
-	time64_t		time_of_death;	/* time at which put reduced usage to 0 */
-	struct afs_addr_list	__rcu *addrs;	/* List of addresses for this server */
-	struct afs_net		*net;		/* Network namespace in which the server resides */
-	struct afs_cell		*cell;		/* cell in which server resides */
-	struct list_head	link;		/* link in cell's server list */
-	struct list_head	grave;		/* link in master graveyard list */
-
-	struct rb_node		master_rb;	/* link in master by-addr tree */
-	struct rw_semaphore	sem;		/* access lock */
+	struct rcu_head		rcu;
+	union {
+		uuid_t		uuid;		/* Server ID */
+		struct afs_uuid	_uuid;
+	};
+
+	struct afs_addr_list	__rcu *addresses;
+	struct rb_node		uuid_rb;	/* Link in net->servers */
+	struct hlist_node	addr4_link;	/* Link in net->fs_addresses4 */
+	struct hlist_node	addr6_link;	/* Link in net->fs_addresses6 */
+	struct hlist_node	proc_link;	/* Link in net->fs_proc */
+	struct afs_server	*gc_next;	/* Next server in manager's list */
+	time64_t		put_time;	/* Time at which last put */
+	time64_t		update_at;	/* Time at which to next update the record */
 	unsigned long		flags;
-#define AFS_SERVER_NEW		0		/* New server, don't inc cb_s_break */
+#define AFS_SERVER_FL_NEW	0		/* New server, don't inc cb_s_break */
+#define AFS_SERVER_FL_NOT_READY	1		/* The record is not ready for use */
+#define AFS_SERVER_FL_NOT_FOUND	2		/* VL server says no such server */
+#define AFS_SERVER_FL_VL_FAIL	3		/* Failed to access VL server */
+#define AFS_SERVER_FL_UPDATING	4
+#define AFS_SERVER_FL_PROBED	5		/* The fileserver has been probed */
+#define AFS_SERVER_FL_PROBING	6		/* Fileserver is being probed */
+	atomic_t		usage;
+	u32			addr_version;	/* Address list version */
 
 	/* file service access */
-	int			fs_state;      	/* 0 or reason FS currently marked dead (-errno) */
-	spinlock_t		fs_lock;	/* access lock */
+	rwlock_t		fs_lock;	/* access lock */
 
 	/* callback promise management */
 	struct list_head	cb_interests;	/* List of superblocks using this server */
@@ -386,32 +382,50 @@ struct afs_cb_interest {
 };
 
 /*
- * AFS volume access record
+ * Replaceable server list.
+ */
+struct afs_server_entry {
+	struct afs_server	*server;
+	struct afs_cb_interest	*cb_interest;
+};
+
+struct afs_server_list {
+	refcount_t		usage;
+	unsigned short		nr_servers;
+	unsigned short		index;		/* Server currently in use */
+	unsigned short		vnovol_mask;	/* Servers to be skipped due to VNOVOL */
+	unsigned int		seq;		/* Set to ->servers_seq when installed */
+	struct afs_server_entry	servers[];
+};
+
+/*
+ * Live AFS volume management.
  */
 struct afs_volume {
+	afs_volid_t		vid;		/* volume ID */
 	atomic_t		usage;
-	struct afs_cell		*cell;		/* cell to which belongs (unrefd ptr) */
-	struct afs_vlocation	*vlocation;	/* volume location */
+	time64_t		update_at;	/* Time at which to next update */
+	struct afs_cell		*cell;		/* Cell to which belongs (pins ref) */
+	struct list_head	proc_link;	/* Link in cell->vl_proc */
+	unsigned long		flags;
+#define AFS_VOLUME_NEEDS_UPDATE	0	/* - T if an update needs performing */
+#define AFS_VOLUME_UPDATING	1	/* - T if an update is in progress */
+#define AFS_VOLUME_WAIT		2	/* - T if users must wait for update */
+#define AFS_VOLUME_DELETED	3	/* - T if volume appears deleted */
+#define AFS_VOLUME_OFFLINE	4	/* - T if volume offline notice given */
+#define AFS_VOLUME_BUSY		5	/* - T if volume busy notice given */
 #ifdef CONFIG_AFS_FSCACHE
 	struct fscache_cookie	*cache;		/* caching cookie */
 #endif
-	afs_volid_t		vid;		/* volume ID */
+	struct afs_server_list	*servers;	/* List of servers on which volume resides */
+	rwlock_t		servers_lock;	/* Lock for ->servers */
+	unsigned int		servers_seq;	/* Incremented each time ->servers changes */
+
 	afs_voltype_t		type;		/* type of volume */
+	short			error;
 	char			type_force;	/* force volume type (suppress R/O -> R/W) */
-	unsigned short		nservers;	/* number of server slots filled */
-	unsigned short		rjservers;	/* number of servers discarded due to -ENOMEDIUM */
-	struct afs_server	*servers[8];	/* servers on which volume resides (ordered) */
-	struct afs_cb_interest	*cb_interests[8]; /* Interests on servers for callbacks */
-	struct rw_semaphore	server_sem;	/* lock for accessing current server */
-};
-
-/*
- * vnode catalogue entry
- */
-struct afs_cache_vnode {
-	afs_vnodeid_t		vnode_id;	/* vnode ID */
-	unsigned		vnode_unique;	/* vnode ID uniquifier */
-	afs_dataversion_t	data_version;	/* data version */
+	u8			name_len;
+	u8			name[AFS_MAXVOLNAME + 1]; /* NUL-padded volume name */
 };
 
 /*
@@ -427,10 +441,8 @@ struct afs_vnode {
 	struct fscache_cookie	*cache;		/* caching cookie */
 #endif
 	struct afs_permits	*permit_cache;	/* cache of permits so far obtained */
+	struct mutex		io_lock;	/* Lock for serialising I/O on this mutex */
 	struct mutex		validate_lock;	/* lock for validating this vnode */
-	wait_queue_head_t	update_waitq;	/* status fetch waitqueue */
-	int			update_cnt;	/* number of outstanding ops that will update the
-						 * status */
 	spinlock_t		writeback_lock;	/* lock for writebacks */
 	spinlock_t		lock;		/* waitqueue/flags lock */
 	unsigned long		flags;
@@ -501,6 +513,7 @@ struct afs_interface {
 struct afs_addr_cursor {
 	struct afs_addr_list	*alist;		/* Current address list (pins ref) */
 	struct sockaddr_rxrpc	*addr;
+	u32			abort_code;
 	unsigned short		start;		/* Starting point in alist->addrs[] */
 	unsigned short		index;		/* Wrapping offset from start to current addr */
 	short			error;
@@ -513,7 +526,21 @@ struct afs_addr_cursor {
  */
 struct afs_fs_cursor {
 	struct afs_addr_cursor	ac;
-	struct afs_server	*server;	/* Current server (pins ref) */
+	struct afs_vnode	*vnode;
+	struct afs_server_list	*server_list;	/* Current server list (pins ref) */
+	struct afs_cb_interest	*cbi;		/* Server on which this resides (pins ref) */
+	struct key		*key;		/* Key for the server */
+	unsigned int		cb_break;	/* cb_break + cb_s_break before the call */
+	unsigned int		cb_break_2;	/* cb_break + cb_s_break (2nd vnode) */
+	unsigned char		start;		/* Initial index in server list */
+	unsigned char		index;		/* Number of servers tried beyond start */
+	unsigned short		flags;
+#define AFS_FS_CURSOR_STOP	0x0001		/* Set to cease iteration */
+#define AFS_FS_CURSOR_VBUSY	0x0002		/* Set if seen VBUSY */
+#define AFS_FS_CURSOR_VMOVED	0x0004		/* Set if seen VMOVED */
+#define AFS_FS_CURSOR_VNOVOL	0x0008		/* Set if seen VNOVOL */
+#define AFS_FS_CURSOR_CUR_ONLY	0x0010		/* Set if current server only (file lock held) */
+#define AFS_FS_CURSOR_NO_VSLEEP	0x0020		/* Set to prevent sleep on VBUSY, VOFFLINE, ... */
 };
 
 /*****************************************************************************/
@@ -537,6 +564,8 @@ extern bool afs_iterate_addresses(struct afs_addr_cursor *);
 extern int afs_end_cursor(struct afs_addr_cursor *);
 extern int afs_set_vl_cursor(struct afs_addr_cursor *, struct afs_cell *);
 
+extern void afs_merge_fs_addr4(struct afs_addr_list *, __be32);
+
 /*
  * cache.c
  */
@@ -558,10 +587,9 @@ extern void afs_init_callback_state(struct afs_server *);
 extern void afs_break_callback(struct afs_vnode *);
 extern void afs_break_callbacks(struct afs_server *, size_t,struct afs_callback[]);
 
-extern int afs_register_server_cb_interest(struct afs_vnode *, struct afs_cb_interest **,
-					   struct afs_server *);
+extern int afs_register_server_cb_interest(struct afs_vnode *, struct afs_server_entry *);
 extern void afs_put_cb_interest(struct afs_net *, struct afs_cb_interest *);
-extern void afs_clear_callback_interests(struct afs_net *, struct afs_volume *);
+extern void afs_clear_callback_interests(struct afs_net *, struct afs_server_list *);
 
 static inline struct afs_cb_interest *afs_get_cb_interest(struct afs_cb_interest *cbi)
 {
@@ -603,6 +631,7 @@ extern const struct file_operations afs_file_operations;
 
 extern int afs_open(struct inode *, struct file *);
 extern int afs_release(struct inode *, struct file *);
+extern int afs_fetch_data(struct afs_vnode *, struct key *, struct afs_read *);
 extern int afs_page_filler(void *, struct page *);
 extern void afs_put_read(struct afs_read *);
 
@@ -619,51 +648,40 @@ extern int afs_flock(struct file *, int, struct file_lock *);
 /*
  * fsclient.c
  */
-extern int afs_fs_fetch_file_status(struct afs_fs_cursor *, struct key *,
-				    struct afs_vnode *, struct afs_volsync *,
-				    bool);
-extern int afs_fs_give_up_callbacks(struct afs_net *, struct afs_server *, bool);
-extern int afs_fs_fetch_data(struct afs_fs_cursor *, struct key *,
-			     struct afs_vnode *, struct afs_read *, bool);
-extern int afs_fs_create(struct afs_fs_cursor *, struct key *,
-			 struct afs_vnode *, const char *, umode_t,
-			 struct afs_fid *, struct afs_file_status *,
-			 struct afs_callback *, bool);
-extern int afs_fs_remove(struct afs_fs_cursor *, struct key *,
-			 struct afs_vnode *, const char *, bool, bool);
-extern int afs_fs_link(struct afs_fs_cursor *, struct key *, struct afs_vnode *,
-		       struct afs_vnode *, const char *, bool);
-extern int afs_fs_symlink(struct afs_fs_cursor *, struct key *,
-			  struct afs_vnode *, const char *, const char *,
-			  struct afs_fid *, struct afs_file_status *, bool);
-extern int afs_fs_rename(struct afs_fs_cursor *, struct key *,
-			 struct afs_vnode *, const char *,
-			 struct afs_vnode *, const char *, bool);
+extern int afs_fs_fetch_file_status(struct afs_fs_cursor *, struct afs_volsync *);
+extern int afs_fs_give_up_callbacks(struct afs_net *, struct afs_server *);
+extern int afs_fs_fetch_data(struct afs_fs_cursor *, struct afs_read *);
+extern int afs_fs_create(struct afs_fs_cursor *, const char *, umode_t,
+			 struct afs_fid *, struct afs_file_status *, struct afs_callback *);
+extern int afs_fs_remove(struct afs_fs_cursor *, const char *, bool);
+extern int afs_fs_link(struct afs_fs_cursor *, struct afs_vnode *, const char *);
+extern int afs_fs_symlink(struct afs_fs_cursor *, const char *, const char *,
+			  struct afs_fid *, struct afs_file_status *);
+extern int afs_fs_rename(struct afs_fs_cursor *, const char *,
+			 struct afs_vnode *, const char *);
 extern int afs_fs_store_data(struct afs_fs_cursor *, struct afs_writeback *,
-			     pgoff_t, pgoff_t, unsigned, unsigned, bool);
-extern int afs_fs_setattr(struct afs_fs_cursor *, struct key *,
-			  struct afs_vnode *, struct iattr *, bool);
-extern int afs_fs_get_volume_status(struct afs_fs_cursor *, struct key *,
-				    struct afs_vnode *,
-				    struct afs_volume_status *, bool);
-extern int afs_fs_set_lock(struct afs_fs_cursor *, struct key *,
-			   struct afs_vnode *, afs_lock_type_t, bool);
-extern int afs_fs_extend_lock(struct afs_fs_cursor *, struct key *,
-			      struct afs_vnode *, bool);
-extern int afs_fs_release_lock(struct afs_fs_cursor *, struct key *,
-			       struct afs_vnode *, bool);
-extern int afs_fs_give_up_all_callbacks(struct afs_server *, struct afs_addr_cursor *,
-					struct key *, bool);
+			     pgoff_t, pgoff_t, unsigned, unsigned);
+extern int afs_fs_setattr(struct afs_fs_cursor *, struct iattr *);
+extern int afs_fs_get_volume_status(struct afs_fs_cursor *, struct afs_volume_status *);
+extern int afs_fs_set_lock(struct afs_fs_cursor *, afs_lock_type_t);
+extern int afs_fs_extend_lock(struct afs_fs_cursor *);
+extern int afs_fs_release_lock(struct afs_fs_cursor *);
+extern int afs_fs_give_up_all_callbacks(struct afs_net *, struct afs_server *,
+					struct afs_addr_cursor *, struct key *);
+extern int afs_fs_get_capabilities(struct afs_net *, struct afs_server *,
+				   struct afs_addr_cursor *, struct key *);
 
 /*
  * inode.c
  */
+extern int afs_fetch_status(struct afs_vnode *, struct key *);
 extern int afs_iget5_test(struct inode *, void *);
 extern struct inode *afs_iget_autocell(struct inode *, const char *, int,
 				       struct key *);
 extern struct inode *afs_iget(struct super_block *, struct key *,
 			      struct afs_fid *, struct afs_file_status *,
-			      struct afs_callback *);
+			      struct afs_callback *,
+			      struct afs_cb_interest *);
 extern void afs_zap_data(struct afs_vnode *);
 extern int afs_validate(struct afs_vnode *, struct key *);
 extern int afs_getattr(const struct path *, struct kstat *, u32, unsigned int);
@@ -734,6 +752,15 @@ extern int afs_proc_cell_setup(struct afs_net *, struct afs_cell *);
 extern void afs_proc_cell_remove(struct afs_net *, struct afs_cell *);
 
 /*
+ * rotate.c
+ */
+extern bool afs_begin_vnode_operation(struct afs_fs_cursor *, struct afs_vnode *,
+				      struct key *);
+extern bool afs_select_fileserver(struct afs_fs_cursor *);
+extern bool afs_select_current_fileserver(struct afs_fs_cursor *);
+extern int afs_end_vnode_operation(struct afs_fs_cursor *);
+
+/*
  * rxrpc.c
  */
 extern struct workqueue_struct *afs_async_calls;
@@ -779,104 +806,62 @@ static inline struct afs_server *afs_get_server(struct afs_server *server)
 	return server;
 }
 
-extern void afs_server_timer(struct timer_list *);
-extern struct afs_server *afs_lookup_server(struct afs_cell *,
-					    struct sockaddr_rxrpc *);
 extern struct afs_server *afs_find_server(struct afs_net *,
 					  const struct sockaddr_rxrpc *);
+extern struct afs_server *afs_find_server_by_uuid(struct afs_net *, const uuid_t *);
+extern struct afs_server *afs_lookup_server(struct afs_cell *, struct key *, const uuid_t *);
 extern void afs_put_server(struct afs_net *, struct afs_server *);
-extern void afs_reap_server(struct work_struct *);
+extern void afs_manage_servers(struct work_struct *);
+extern void afs_servers_timer(struct timer_list *);
 extern void __net_exit afs_purge_servers(struct afs_net *);
+extern bool afs_probe_fileserver(struct afs_fs_cursor *);
+extern bool afs_check_server_record(struct afs_fs_cursor *, struct afs_server *);
 
 /*
- * super.c
+ * server_list.c
  */
-extern int __init afs_fs_init(void);
-extern void __exit afs_fs_exit(void);
+static inline struct afs_server_list *afs_get_serverlist(struct afs_server_list *slist)
+{
+	refcount_inc(&slist->usage);
+	return slist;
+}
 
-/*
- * vlclient.c
- */
-extern int afs_vl_get_entry_by_name(struct afs_net *, struct afs_addr_cursor *,
-				    struct key *, const char *,
-				    struct afs_cache_vlocation *, bool);
-extern int afs_vl_get_entry_by_id(struct afs_net *, struct afs_addr_cursor *,
-				  struct key *, afs_volid_t, afs_voltype_t,
-				  struct afs_cache_vlocation *, bool);
+extern void afs_put_serverlist(struct afs_net *, struct afs_server_list *);
+extern struct afs_server_list *afs_alloc_server_list(struct afs_cell *, struct key *,
+						     struct afs_vldb_entry *,
+						     u8);
+extern bool afs_annotate_server_list(struct afs_server_list *, struct afs_server_list *);
 
 /*
- * vlocation.c
+ * super.c
  */
-extern struct workqueue_struct *afs_vlocation_update_worker;
-
-#define afs_get_vlocation(V) do { atomic_inc(&(V)->usage); } while(0)
-
-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_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 *);
+extern int __init afs_fs_init(void);
+extern void __exit afs_fs_exit(void);
 
 /*
- * vnode.c
+ * vlclient.c
  */
-static inline struct afs_vnode *AFS_FS_I(struct inode *inode)
-{
-	return container_of(inode, struct afs_vnode, vfs_inode);
-}
-
-static inline struct inode *AFS_VNODE_TO_I(struct afs_vnode *vnode)
-{
-	return &vnode->vfs_inode;
-}
-
-extern void afs_vnode_finalise_status_update(struct afs_vnode *,
-					     struct afs_server *);
-extern int afs_vnode_fetch_status(struct afs_vnode *, struct key *, bool);
-extern int afs_vnode_fetch_data(struct afs_vnode *, struct key *,
-				struct afs_read *);
-extern int afs_vnode_create(struct afs_vnode *, struct key *, const char *,
-			    umode_t, struct afs_fid *, struct afs_file_status *,
-			    struct afs_callback *, struct afs_server **);
-extern int afs_vnode_remove(struct afs_vnode *, struct key *, const char *,
-			    bool);
-extern int afs_vnode_link(struct afs_vnode *, struct afs_vnode *, struct key *,
-			  const char *);
-extern int afs_vnode_symlink(struct afs_vnode *, struct key *, const char *,
-			     const char *, struct afs_fid *,
-			     struct afs_file_status *, struct afs_server **);
-extern int afs_vnode_rename(struct afs_vnode *, struct afs_vnode *,
-			    struct key *, const char *, const char *);
-extern int afs_vnode_store_data(struct afs_writeback *, pgoff_t, pgoff_t,
-				unsigned, unsigned);
-extern int afs_vnode_setattr(struct afs_vnode *, struct key *, struct iattr *);
-extern int afs_vnode_get_volume_status(struct afs_vnode *, struct key *,
-				       struct afs_volume_status *);
-extern int afs_vnode_set_lock(struct afs_vnode *, struct key *,
-			      afs_lock_type_t);
-extern int afs_vnode_extend_lock(struct afs_vnode *, struct key *);
-extern int afs_vnode_release_lock(struct afs_vnode *, struct key *);
+extern struct afs_vldb_entry *afs_vl_get_entry_by_name_u(struct afs_net *,
+							 struct afs_addr_cursor *,
+							 struct key *, const char *, int);
+extern struct afs_addr_list *afs_vl_get_addrs_u(struct afs_net *, struct afs_addr_cursor *,
+						struct key *, const uuid_t *);
 
 /*
  * volume.c
  */
-static inline struct afs_volume *afs_get_volume(struct afs_volume *volume)
+static inline struct afs_volume *__afs_get_volume(struct afs_volume *volume)
 {
 	if (volume)
 		atomic_inc(&volume->usage);
 	return volume;
 }
 
+extern struct afs_volume *afs_create_volume(struct afs_mount_params *);
+extern void afs_activate_volume(struct afs_volume *);
+extern void afs_deactivate_volume(struct afs_volume *);
 extern void afs_put_volume(struct afs_cell *, struct afs_volume *);
-extern struct afs_volume *afs_volume_lookup(struct afs_mount_params *);
-extern void afs_init_fs_cursor(struct afs_fs_cursor *, struct afs_vnode *);
-extern int afs_set_fs_cursor(struct afs_fs_cursor *, struct afs_vnode *);
-extern bool afs_volume_pick_fileserver(struct afs_fs_cursor *, struct afs_vnode *);
-extern bool afs_iterate_fs_cursor(struct afs_fs_cursor *, struct afs_vnode *);
-extern int afs_end_fs_cursor(struct afs_fs_cursor *, struct afs_net *);
+extern int afs_check_volume_status(struct afs_volume *, struct key *);
 
 /*
  * write.c
@@ -903,6 +888,38 @@ extern int afs_fsync(struct file *, loff_t, loff_t, int);
 extern const struct xattr_handler *afs_xattr_handlers[];
 extern ssize_t afs_listxattr(struct dentry *, char *, size_t);
 
+
+/*
+ * Miscellaneous inline functions.
+ */
+static inline struct afs_vnode *AFS_FS_I(struct inode *inode)
+{
+	return container_of(inode, struct afs_vnode, vfs_inode);
+}
+
+static inline struct inode *AFS_VNODE_TO_I(struct afs_vnode *vnode)
+{
+	return &vnode->vfs_inode;
+}
+
+static inline void afs_vnode_commit_status(struct afs_fs_cursor *fc,
+					   struct afs_vnode *vnode,
+					   unsigned int cb_break)
+{
+	if (fc->ac.error == 0)
+		afs_cache_permit(vnode, fc->key, cb_break);
+}
+
+static inline void afs_check_for_remote_deletion(struct afs_fs_cursor *fc,
+						 struct afs_vnode *vnode)
+{
+	if (fc->ac.error == -ENOENT) {
+		set_bit(AFS_VNODE_DELETED, &vnode->flags);
+		afs_break_callback(vnode);
+	}
+}
+
+
 /*****************************************************************************/
 /*
  * debug tracing