1 files changed, 197 insertions, 102 deletions

diff --git a/fs/afs/server.c b/fs/afs/server.c
index 11b90ac7ea30..039e3488511c 100644
--- a/fs/afs/server.c
+++ b/fs/afs/server.c
@@ -12,19 +12,11 @@
 #include "protocol_yfs.h"
 
 static unsigned afs_server_gc_delay = 10;	/* Server record timeout in seconds */
-static unsigned afs_server_update_delay = 30;	/* Time till VLDB recheck in secs */
 static atomic_t afs_server_debug_id;
 
-static void afs_inc_servers_outstanding(struct afs_net *net)
-{
-	atomic_inc(&net->servers_outstanding);
-}
-
-static void afs_dec_servers_outstanding(struct afs_net *net)
-{
-	if (atomic_dec_and_test(&net->servers_outstanding))
-		wake_up_var(&net->servers_outstanding);
-}
+static struct afs_server *afs_maybe_use_server(struct afs_server *,
+					       enum afs_server_trace);
+static void __afs_put_server(struct afs_net *, struct afs_server *);
 
 /*
  * Find a server by one of its addresses.
@@ -41,7 +33,7 @@ struct afs_server *afs_find_server(struct afs_net *net,
 
 	do {
 		if (server)
-			afs_put_server(net, server, afs_server_trace_put_find_rsq);
+			afs_unuse_server_notime(net, server, afs_server_trace_put_find_rsq);
 		server = NULL;
 		read_seqbegin_or_lock(&net->fs_addr_lock, &seq);
 
@@ -79,9 +71,9 @@ struct afs_server *afs_find_server(struct afs_net *net,
 		}
 
 		server = NULL;
+		continue;
 	found:
-		if (server && !atomic_inc_not_zero(&server->usage))
-			server = NULL;
+		server = afs_maybe_use_server(server, afs_server_trace_get_by_addr);
 
 	} while (need_seqretry(&net->fs_addr_lock, seq));
 
@@ -92,7 +84,7 @@ struct afs_server *afs_find_server(struct afs_net *net,
 }
 
 /*
- * Look up a server by its UUID
+ * Look up a server by its UUID and mark it active.
  */
 struct afs_server *afs_find_server_by_uuid(struct afs_net *net, const uuid_t *uuid)
 {
@@ -108,7 +100,7 @@ struct afs_server *afs_find_server_by_uuid(struct afs_net *net, const uuid_t *uu
 		 * changes.
 		 */
 		if (server)
-			afs_put_server(net, server, afs_server_trace_put_uuid_rsq);
+			afs_unuse_server(net, server, afs_server_trace_put_uuid_rsq);
 		server = NULL;
 
 		read_seqbegin_or_lock(&net->fs_lock, &seq);
@@ -123,7 +115,7 @@ struct afs_server *afs_find_server_by_uuid(struct afs_net *net, const uuid_t *uu
 			} else if (diff > 0) {
 				p = p->rb_right;
 			} else {
-				afs_get_server(server, afs_server_trace_get_by_uuid);
+				afs_use_server(server, afs_server_trace_get_by_uuid);
 				break;
 			}
 
@@ -138,13 +130,16 @@ struct afs_server *afs_find_server_by_uuid(struct afs_net *net, const uuid_t *uu
 }
 
 /*
- * Install a server record in the namespace tree
+ * Install a server record in the namespace tree.  If there's a clash, we stick
+ * it into a list anchored on whichever afs_server struct is actually in the
+ * tree.
  */
-static struct afs_server *afs_install_server(struct afs_net *net,
+static struct afs_server *afs_install_server(struct afs_cell *cell,
 					     struct afs_server *candidate)
 {
 	const struct afs_addr_list *alist;
-	struct afs_server *server;
+	struct afs_server *server, *next;
+	struct afs_net *net = cell->net;
 	struct rb_node **pp, *p;
 	int diff;
 
@@ -160,12 +155,30 @@ static struct afs_server *afs_install_server(struct afs_net *net,
 		_debug("- consider %p", p);
 		server = rb_entry(p, struct afs_server, uuid_rb);
 		diff = memcmp(&candidate->uuid, &server->uuid, sizeof(uuid_t));
-		if (diff < 0)
+		if (diff < 0) {
 			pp = &(*pp)->rb_left;
-		else if (diff > 0)
+		} else if (diff > 0) {
 			pp = &(*pp)->rb_right;
-		else
-			goto exists;
+		} else {
+			if (server->cell == cell)
+				goto exists;
+
+			/* We have the same UUID representing servers in
+			 * different cells.  Append the new server to the list.
+			 */
+			for (;;) {
+				next = rcu_dereference_protected(
+					server->uuid_next,
+					lockdep_is_held(&net->fs_lock.lock));
+				if (!next)
+					break;
+				server = next;
+			}
+			rcu_assign_pointer(server->uuid_next, candidate);
+			candidate->uuid_prev = server;
+			server = candidate;
+			goto added_dup;
+		}
 	}
 
 	server = candidate;
@@ -173,6 +186,7 @@ static struct afs_server *afs_install_server(struct afs_net *net,
 	rb_insert_color(&server->uuid_rb, &net->fs_servers);
 	hlist_add_head_rcu(&server->proc_link, &net->fs_proc);
 
+added_dup:
 	write_seqlock(&net->fs_addr_lock);
 	alist = rcu_dereference_protected(server->addresses,
 					  lockdep_is_held(&net->fs_addr_lock.lock));
@@ -199,13 +213,14 @@ exists:
 }
 
 /*
- * allocate a new server record
+ * Allocate a new server record and mark it active.
  */
-static struct afs_server *afs_alloc_server(struct afs_net *net,
+static struct afs_server *afs_alloc_server(struct afs_cell *cell,
 					   const uuid_t *uuid,
 					   struct afs_addr_list *alist)
 {
 	struct afs_server *server;
+	struct afs_net *net = cell->net;
 
 	_enter("");
 
@@ -213,20 +228,21 @@ static struct afs_server *afs_alloc_server(struct afs_net *net,
 	if (!server)
 		goto enomem;
 
-	atomic_set(&server->usage, 1);
+	atomic_set(&server->ref, 1);
+	atomic_set(&server->active, 1);
 	server->debug_id = atomic_inc_return(&afs_server_debug_id);
 	RCU_INIT_POINTER(server->addresses, alist);
 	server->addr_version = alist->version;
 	server->uuid = *uuid;
-	server->update_at = ktime_get_real_seconds() + afs_server_update_delay;
 	rwlock_init(&server->fs_lock);
-	INIT_HLIST_HEAD(&server->cb_volumes);
-	rwlock_init(&server->cb_break_lock);
 	init_waitqueue_head(&server->probe_wq);
+	INIT_LIST_HEAD(&server->probe_link);
 	spin_lock_init(&server->probe_lock);
+	server->cell = cell;
+	server->rtt = UINT_MAX;
 
 	afs_inc_servers_outstanding(net);
-	trace_afs_server(server, 1, afs_server_trace_alloc);
+	trace_afs_server(server, 1, 1, afs_server_trace_alloc);
 	_leave(" = %p", server);
 	return server;
 
@@ -264,7 +280,7 @@ static struct afs_addr_list *afs_vl_lookup_addrs(struct afs_cell *cell,
  * Get or create a fileserver record.
  */
 struct afs_server *afs_lookup_server(struct afs_cell *cell, struct key *key,
-				     const uuid_t *uuid)
+				     const uuid_t *uuid, u32 addr_version)
 {
 	struct afs_addr_list *alist;
 	struct afs_server *server, *candidate;
@@ -272,26 +288,34 @@ struct afs_server *afs_lookup_server(struct afs_cell *cell, struct key *key,
 	_enter("%p,%pU", cell->net, uuid);
 
 	server = afs_find_server_by_uuid(cell->net, uuid);
-	if (server)
+	if (server) {
+		if (server->addr_version != addr_version)
+			set_bit(AFS_SERVER_FL_NEEDS_UPDATE, &server->flags);
 		return server;
+	}
 
 	alist = afs_vl_lookup_addrs(cell, key, uuid);
 	if (IS_ERR(alist))
 		return ERR_CAST(alist);
 
-	candidate = afs_alloc_server(cell->net, uuid, alist);
+	candidate = afs_alloc_server(cell, uuid, alist);
 	if (!candidate) {
 		afs_put_addrlist(alist);
 		return ERR_PTR(-ENOMEM);
 	}
 
-	server = afs_install_server(cell->net, candidate);
+	server = afs_install_server(cell, candidate);
 	if (server != candidate) {
 		afs_put_addrlist(alist);
 		kfree(candidate);
+	} else {
+		/* Immediately dispatch an asynchronous probe to each interface
+		 * on the fileserver.  This will make sure the repeat-probing
+		 * service is started.
+		 */
+		afs_fs_probe_fileserver(cell->net, server, key, true);
 	}
 
-	_leave(" = %p{%d}", server, atomic_read(&server->usage));
 	return server;
 }
 
@@ -327,9 +351,38 @@ void afs_servers_timer(struct timer_list *timer)
 struct afs_server *afs_get_server(struct afs_server *server,
 				  enum afs_server_trace reason)
 {
-	unsigned int u = atomic_inc_return(&server->usage);
+	unsigned int u = atomic_inc_return(&server->ref);
+
+	trace_afs_server(server, u, atomic_read(&server->active), reason);
+	return server;
+}
+
+/*
+ * Try to get a reference on a server object.
+ */
+static struct afs_server *afs_maybe_use_server(struct afs_server *server,
+					       enum afs_server_trace reason)
+{
+	unsigned int r = atomic_fetch_add_unless(&server->ref, 1, 0);
+	unsigned int a;
+
+	if (r == 0)
+		return NULL;
+
+	a = atomic_inc_return(&server->active);
+	trace_afs_server(server, r, a, reason);
+	return server;
+}
+
+/*
+ * Get an active count on a server object.
+ */
+struct afs_server *afs_use_server(struct afs_server *server, enum afs_server_trace reason)
+{
+	unsigned int r = atomic_inc_return(&server->ref);
+	unsigned int a = atomic_inc_return(&server->active);
 
-	trace_afs_server(server, u, reason);
+	trace_afs_server(server, r, a, reason);
 	return server;
 }
 
@@ -344,32 +397,57 @@ void afs_put_server(struct afs_net *net, struct afs_server *server,
 	if (!server)
 		return;
 
-	server->put_time = ktime_get_real_seconds();
-
-	usage = atomic_dec_return(&server->usage);
+	usage = atomic_dec_return(&server->ref);
+	trace_afs_server(server, usage, atomic_read(&server->active), reason);
+	if (unlikely(usage == 0))
+		__afs_put_server(net, server);
+}
 
-	trace_afs_server(server, usage, reason);
+/*
+ * Drop an active count on a server object without updating the last-unused
+ * time.
+ */
+void afs_unuse_server_notime(struct afs_net *net, struct afs_server *server,
+			     enum afs_server_trace reason)
+{
+	if (server) {
+		unsigned int active = atomic_dec_return(&server->active);
 
-	if (likely(usage > 0))
-		return;
+		if (active == 0)
+			afs_set_server_timer(net, afs_server_gc_delay);
+		afs_put_server(net, server, reason);
+	}
+}
 
-	afs_set_server_timer(net, afs_server_gc_delay);
+/*
+ * Drop an active count on a server object.
+ */
+void afs_unuse_server(struct afs_net *net, struct afs_server *server,
+		      enum afs_server_trace reason)
+{
+	if (server) {
+		server->unuse_time = ktime_get_real_seconds();
+		afs_unuse_server_notime(net, server, reason);
+	}
 }
 
 static void afs_server_rcu(struct rcu_head *rcu)
 {
 	struct afs_server *server = container_of(rcu, struct afs_server, rcu);
 
-	trace_afs_server(server, atomic_read(&server->usage),
-			 afs_server_trace_free);
+	trace_afs_server(server, atomic_read(&server->ref),
+			 atomic_read(&server->active), afs_server_trace_free);
 	afs_put_addrlist(rcu_access_pointer(server->addresses));
 	kfree(server);
 }
 
-/*
- * destroy a dead server
- */
-static void afs_destroy_server(struct afs_net *net, struct afs_server *server)
+static void __afs_put_server(struct afs_net *net, struct afs_server *server)
+{
+	call_rcu(&server->rcu, afs_server_rcu);
+	afs_dec_servers_outstanding(net);
+}
+
+static void afs_give_up_callbacks(struct afs_net *net, struct afs_server *server)
 {
 	struct afs_addr_list *alist = rcu_access_pointer(server->addresses);
 	struct afs_addr_cursor ac = {
@@ -378,19 +456,18 @@ static void afs_destroy_server(struct afs_net *net, struct afs_server *server)
 		.error	= 0,
 	};
 
-	trace_afs_server(server, atomic_read(&server->usage),
-			 afs_server_trace_give_up_cb);
+	afs_fs_give_up_all_callbacks(net, server, &ac, NULL);
+}
 
+/*
+ * destroy a dead server
+ */
+static void afs_destroy_server(struct afs_net *net, struct afs_server *server)
+{
 	if (test_bit(AFS_SERVER_FL_MAY_HAVE_CB, &server->flags))
-		afs_fs_give_up_all_callbacks(net, server, &ac, NULL);
+		afs_give_up_callbacks(net, server);
 
-	wait_var_event(&server->probe_outstanding,
-		       atomic_read(&server->probe_outstanding) == 0);
-
-	trace_afs_server(server, atomic_read(&server->usage),
-			 afs_server_trace_destroy);
-	call_rcu(&server->rcu, afs_server_rcu);
-	afs_dec_servers_outstanding(net);
+	afs_put_server(net, server, afs_server_trace_destroy);
 }
 
 /*
@@ -398,32 +475,49 @@ static void afs_destroy_server(struct afs_net *net, struct afs_server *server)
  */
 static void afs_gc_servers(struct afs_net *net, struct afs_server *gc_list)
 {
-	struct afs_server *server;
-	bool deleted;
-	int usage;
+	struct afs_server *server, *next, *prev;
+	int active;
 
 	while ((server = gc_list)) {
 		gc_list = server->gc_next;
 
 		write_seqlock(&net->fs_lock);
-		usage = 1;
-		deleted = atomic_try_cmpxchg(&server->usage, &usage, 0);
-		trace_afs_server(server, usage, afs_server_trace_gc);
-		if (deleted) {
-			rb_erase(&server->uuid_rb, &net->fs_servers);
-			hlist_del_rcu(&server->proc_link);
-		}
-		write_sequnlock(&net->fs_lock);
 
-		if (deleted) {
-			write_seqlock(&net->fs_addr_lock);
+		active = atomic_read(&server->active);
+		if (active == 0) {
+			trace_afs_server(server, atomic_read(&server->ref),
+					 active, afs_server_trace_gc);
+			next = rcu_dereference_protected(
+				server->uuid_next, lockdep_is_held(&net->fs_lock.lock));
+			prev = server->uuid_prev;
+			if (!prev) {
+				/* The one at the front is in the tree */
+				if (!next) {
+					rb_erase(&server->uuid_rb, &net->fs_servers);
+				} else {
+					rb_replace_node_rcu(&server->uuid_rb,
+							    &next->uuid_rb,
+							    &net->fs_servers);
+					next->uuid_prev = NULL;
+				}
+			} else {
+				/* This server is not at the front */
+				rcu_assign_pointer(prev->uuid_next, next);
+				if (next)
+					next->uuid_prev = prev;
+			}
+
+			list_del(&server->probe_link);
+			hlist_del_rcu(&server->proc_link);
 			if (!hlist_unhashed(&server->addr4_link))
 				hlist_del_rcu(&server->addr4_link);
 			if (!hlist_unhashed(&server->addr6_link))
 				hlist_del_rcu(&server->addr6_link);
-			write_sequnlock(&net->fs_addr_lock);
-			afs_destroy_server(net, server);
 		}
+		write_sequnlock(&net->fs_lock);
+
+		if (active == 0)
+			afs_destroy_server(net, server);
 	}
 }
 
@@ -452,15 +546,14 @@ void afs_manage_servers(struct work_struct *work)
 	for (cursor = rb_first(&net->fs_servers); cursor; cursor = rb_next(cursor)) {
 		struct afs_server *server =
 			rb_entry(cursor, struct afs_server, uuid_rb);
-		int usage = atomic_read(&server->usage);
+		int active = atomic_read(&server->active);
 
-		_debug("manage %pU %u", &server->uuid, usage);
+		_debug("manage %pU %u", &server->uuid, active);
 
-		ASSERTCMP(usage, >=, 1);
-		ASSERTIFCMP(purging, usage, ==, 1);
+		ASSERTIFCMP(purging, active, ==, 0);
 
-		if (usage == 1) {
-			time64_t expire_at = server->put_time;
+		if (active == 0) {
+			time64_t expire_at = server->unuse_time;
 
 			if (!test_bit(AFS_SERVER_FL_VL_FAIL, &server->flags) &&
 			    !test_bit(AFS_SERVER_FL_NOT_FOUND, &server->flags))
@@ -525,26 +618,27 @@ void afs_purge_servers(struct afs_net *net)
 /*
  * Get an update for a server's address list.
  */
-static noinline bool afs_update_server_record(struct afs_fs_cursor *fc, struct afs_server *server)
+static noinline bool afs_update_server_record(struct afs_operation *op,
+					      struct afs_server *server)
 {
 	struct afs_addr_list *alist, *discard;
 
 	_enter("");
 
-	trace_afs_server(server, atomic_read(&server->usage), afs_server_trace_update);
+	trace_afs_server(server, atomic_read(&server->ref), atomic_read(&server->active),
+			 afs_server_trace_update);
 
-	alist = afs_vl_lookup_addrs(fc->vnode->volume->cell, fc->key,
-				    &server->uuid);
+	alist = afs_vl_lookup_addrs(op->volume->cell, op->key, &server->uuid);
 	if (IS_ERR(alist)) {
 		if ((PTR_ERR(alist) == -ERESTARTSYS ||
 		     PTR_ERR(alist) == -EINTR) &&
-		    !(fc->flags & AFS_FS_CURSOR_INTR) &&
+		    (op->flags & AFS_OPERATION_UNINTR) &&
 		    server->addresses) {
 			_leave(" = t [intr]");
 			return true;
 		}
-		fc->error = PTR_ERR(alist);
-		_leave(" = f [%d]", fc->error);
+		op->error = PTR_ERR(alist);
+		_leave(" = f [%d]", op->error);
 		return false;
 	}
 
@@ -558,7 +652,6 @@ static noinline bool afs_update_server_record(struct afs_fs_cursor *fc, struct a
 		write_unlock(&server->fs_lock);
 	}
 
-	server->update_at = ktime_get_real_seconds() + afs_server_update_delay;
 	afs_put_addrlist(discard);
 	_leave(" = t");
 	return true;
@@ -567,10 +660,8 @@ static noinline bool afs_update_server_record(struct afs_fs_cursor *fc, struct a
 /*
  * See if a server's address list needs updating.
  */
-bool afs_check_server_record(struct afs_fs_cursor *fc, struct afs_server *server)
+bool afs_check_server_record(struct afs_operation *op, struct afs_server *server)
 {
-	time64_t now = ktime_get_real_seconds();
-	long diff;
 	bool success;
 	int ret, retries = 0;
 
@@ -579,25 +670,29 @@ bool afs_check_server_record(struct afs_fs_cursor *fc, struct afs_server *server
 	ASSERT(server);
 
 retry:
-	diff = READ_ONCE(server->update_at) - now;
-	if (diff > 0) {
-		_leave(" = t [not now %ld]", diff);
-		return true;
-	}
+	if (test_bit(AFS_SERVER_FL_UPDATING, &server->flags))
+		goto wait;
+	if (test_bit(AFS_SERVER_FL_NEEDS_UPDATE, &server->flags))
+		goto update;
+	_leave(" = t [good]");
+	return true;
 
+update:
 	if (!test_and_set_bit_lock(AFS_SERVER_FL_UPDATING, &server->flags)) {
-		success = afs_update_server_record(fc, server);
+		clear_bit(AFS_SERVER_FL_NEEDS_UPDATE, &server->flags);
+		success = afs_update_server_record(op, server);
 		clear_bit_unlock(AFS_SERVER_FL_UPDATING, &server->flags);
 		wake_up_bit(&server->flags, AFS_SERVER_FL_UPDATING);
 		_leave(" = %d", success);
 		return success;
 	}
 
+wait:
 	ret = wait_on_bit(&server->flags, AFS_SERVER_FL_UPDATING,
-			  (fc->flags & AFS_FS_CURSOR_INTR) ?
-			  TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE);
+			  (op->flags & AFS_OPERATION_UNINTR) ?
+			  TASK_UNINTERRUPTIBLE : TASK_INTERRUPTIBLE);
 	if (ret == -ERESTARTSYS) {
-		fc->error = ret;
+		op->error = ret;
 		_leave(" = f [intr]");
 		return false;
 	}