afs: Reorganise volume and server trees to be rooted on the cell

Reorganise afs_volume objects such that they're in a tree keyed on volume
ID, rooted at on an afs_cell object rather than being in multiple trees,
each of which is rooted on an afs_server object.

afs_server structs become per-cell and acquire a pointer to the cell.

The process of breaking a callback then starts with finding the server by
its network address, following that to the cell and then looking up each
volume ID in the volume tree.

This is simpler than the afs_vol_interest/afs_cb_interest N:M mapping web
and allows those structs and the code for maintaining them to be simplified
or removed.

It does make a couple of things a bit more tricky, though:

 (1) Operations now start with a volume, not a server, so there can be more
     than one answer as to whether or not the server we'll end up using
     supports the FS.InlineBulkStatus RPC.

 (2) CB RPC operations that specify the server UUID.  There's still a tree
     of servers by UUID on the afs_net struct, but the UUIDs in it aren't
     guaranteed unique.

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

1 files changed, 22 insertions, 56 deletions

diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index e084936066b0..c64c2b47ece7 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -103,7 +103,6 @@ struct afs_call {
 	struct afs_net		*net;		/* The network namespace */
 	struct afs_server	*server;	/* The fileserver record if fs op (pins ref) */
 	struct afs_vlserver	*vlserver;	/* The vlserver record if vl op */
-	struct afs_cb_interest	*cbi;		/* Callback interest for server used */
 	void			*request;	/* request data (first part) */
 	struct iov_iter		def_iter;	/* Default buffer/data iterator */
 	struct iov_iter		*iter;		/* Iterator currently in use */
@@ -375,9 +374,14 @@ struct afs_cell {
 	enum dns_lookup_status	dns_status:8;	/* Latest status of data from lookup */
 	unsigned int		dns_lookup_count; /* Counter of DNS lookups */
 
+	/* The volumes belonging to this cell */
+	struct rb_root		volumes;	/* Tree of volumes on this server */
+	struct hlist_head	proc_volumes;	/* procfs volume list */
+	seqlock_t		volume_lock;	/* For volumes */
+
 	/* Active fileserver interaction state. */
-	struct list_head	proc_volumes;	/* procfs volume list */
-	rwlock_t		proc_lock;
+	struct rb_root		fs_servers;	/* afs_server (by server UUID) */
+	seqlock_t		fs_lock;	/* For fs_servers  */
 
 	/* VL server list. */
 	rwlock_t		vl_servers_lock; /* Lock on vl_servers */
@@ -481,7 +485,8 @@ struct afs_server {
 	};
 
 	struct afs_addr_list	__rcu *addresses;
-	struct rb_node		uuid_rb;	/* Link in net->fs_servers */
+	struct afs_cell		*cell;		/* Cell to which belongs (pins ref) */
+	struct rb_node		uuid_rb;	/* Link in cell->fs_servers */
 	struct list_head	probe_link;	/* Link in net->fs_probe_list */
 	struct hlist_node	addr4_link;	/* Link in net->fs_addresses4 */
 	struct hlist_node	addr6_link;	/* Link in net->fs_addresses6 */
@@ -507,9 +512,7 @@ struct afs_server {
 	rwlock_t		fs_lock;	/* access lock */
 
 	/* callback promise management */
-	struct rb_root		cb_volumes;	/* List of volume interests on this server */
 	unsigned		cb_s_break;	/* Break-everything counter. */
-	seqlock_t		cb_break_lock;	/* Volume finding lock */
 
 	/* Probe state */
 	unsigned long		probed_at;	/* Time last probe was dispatched (jiffies) */
@@ -528,36 +531,10 @@ struct afs_server {
 };
 
 /*
- * Volume collation in the server's callback interest list.
- */
-struct afs_vol_interest {
-	struct rb_node		srv_node;	/* Link in server->cb_volumes */
-	struct hlist_head	cb_interests;	/* List of callback interests on the server */
-	union {
-		struct rcu_head	rcu;
-		afs_volid_t	vid;		/* Volume ID to match */
-	};
-	unsigned int		usage;
-};
-
-/*
- * Interest by a superblock on a server.
- */
-struct afs_cb_interest {
-	struct hlist_node	cb_vlink;	/* Link in vol_interest->cb_interests */
-	struct afs_vol_interest	*vol_interest;
-	struct afs_server	*server;	/* Server on which this interest resides */
-	struct super_block	*sb;		/* Superblock on which inodes reside */
-	struct rcu_head		rcu;
-	refcount_t		usage;
-};
-
-/*
  * Replaceable volume server list.
  */
 struct afs_server_entry {
 	struct afs_server	*server;
-	struct afs_cb_interest	*cb_interest;
 };
 
 struct afs_server_list {
@@ -575,11 +552,16 @@ struct afs_server_list {
  * Live AFS volume management.
  */
 struct afs_volume {
-	afs_volid_t		vid;		/* volume ID */
+	union {
+		struct rcu_head	rcu;
+		afs_volid_t	vid;		/* volume ID */
+	};
 	atomic_t		usage;
 	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 */
+	struct rb_node		cell_node;	/* Link in cell->volumes */
+	struct hlist_node	proc_link;	/* Link in cell->proc_volumes */
+	struct super_block __rcu *sb;		/* Superblock on which inodes reside */
 	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 */
@@ -587,6 +569,7 @@ struct afs_volume {
 #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 */
+#define AFS_VOLUME_MAYBE_NO_IBULK 6	/* - T if some servers don't have InlineBulkStatus */
 #ifdef CONFIG_AFS_FSCACHE
 	struct fscache_cookie	*cache;		/* caching cookie */
 #endif
@@ -598,7 +581,6 @@ struct afs_volume {
 	rwlock_t		cb_v_break_lock;
 
 	afs_voltype_t		type;		/* type of volume */
-	short			error;
 	char			type_force;	/* force volume type (suppress R/O -> R/W) */
 	u8			name_len;
 	u8			name[AFS_MAXVOLNAME + 1]; /* NUL-padded volume name */
@@ -659,11 +641,11 @@ struct afs_vnode {
 	afs_lock_type_t		lock_type : 8;
 
 	/* outstanding callback notification on this file */
-	struct afs_cb_interest __rcu *cb_interest; /* Server on which this resides */
+	void			*cb_server;	/* Server with callback/filelock */
 	unsigned int		cb_s_break;	/* Mass break counter on ->server */
 	unsigned int		cb_v_break;	/* Mass break counter on ->volume */
 	unsigned int		cb_break;	/* Break counter on vnode */
-	seqlock_t		cb_lock;	/* Lock for ->cb_interest, ->status, ->cb_*break */
+	seqlock_t		cb_lock;	/* Lock for ->cb_server, ->status, ->cb_*break */
 
 	time64_t		cb_expires_at;	/* time at which callback expires */
 };
@@ -833,7 +815,7 @@ struct afs_operation {
 	/* Fileserver iteration state */
 	struct afs_addr_cursor	ac;
 	struct afs_server_list	*server_list;	/* Current server list (pins ref) */
-	struct afs_cb_interest	*cbi;		/* Server on which this resides (pins ref) */
+	struct afs_server	*server;	/* Server we're using (ref pinned by server_list) */
 	struct afs_call		*call;
 	unsigned long		untried;	/* Bitmask of untried servers */
 	short			index;		/* Current server */
@@ -907,29 +889,15 @@ extern void __afs_break_callback(struct afs_vnode *, enum afs_cb_break_reason);
 extern void afs_break_callback(struct afs_vnode *, enum afs_cb_break_reason);
 extern void afs_break_callbacks(struct afs_server *, size_t, struct afs_callback_break *);
 
-extern int afs_register_server_cb_interest(struct afs_vnode *,
-					   struct afs_server_list *, unsigned int);
-extern void afs_put_cb_interest(struct afs_net *, struct afs_cb_interest *);
-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)
-{
-	if (cbi)
-		refcount_inc(&cbi->usage);
-	return cbi;
-}
-
 static inline unsigned int afs_calc_vnode_cb_break(struct afs_vnode *vnode)
 {
 	return vnode->cb_break + vnode->cb_v_break;
 }
 
 static inline bool afs_cb_is_broken(unsigned int cb_break,
-				    const struct afs_vnode *vnode,
-				    const struct afs_cb_interest *cbi)
+				    const struct afs_vnode *vnode)
 {
-	return !cbi || cb_break != (vnode->cb_break +
-				    vnode->volume->cb_v_break);
+	return cb_break != (vnode->cb_break + vnode->volume->cb_v_break);
 }
 
 /*
@@ -1182,7 +1150,6 @@ static inline void afs_put_sysnames(struct afs_sysnames *sysnames) {}
  * rotate.c
  */
 extern bool afs_select_fileserver(struct afs_operation *);
-extern bool afs_select_current_fileserver(struct afs_operation *);
 extern void afs_dump_edestaddrreq(const struct afs_operation *);
 
 /*
@@ -1212,7 +1179,6 @@ static inline void afs_make_op_call(struct afs_operation *op, struct afs_call *c
 	op->type = call->type;
 	call->op = op;
 	call->key = op->key;
-	call->cbi = afs_get_cb_interest(op->cbi);
 	call->intr = !(op->flags & AFS_OPERATION_UNINTR);
 	afs_make_call(&op->ac, call, gfp);
 }