1 files changed, 516 insertions, 207 deletions

diff --git a/fs/afs/server.c b/fs/afs/server.c
index f342acf3547d..c4428ebddb1d 100644
--- a/fs/afs/server.c
+++ b/fs/afs/server.c
@@ -1,322 +1,631 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /* AFS server record management
  *
  * Copyright (C) 2002, 2007 Red Hat, Inc. All Rights Reserved.
  * Written by David Howells (dhowells@redhat.com)
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; either version
- * 2 of the License, or (at your option) any later version.
  */
 
 #include <linux/sched.h>
 #include <linux/slab.h>
+#include "afs_fs.h"
 #include "internal.h"
+#include "protocol_yfs.h"
 
-static unsigned afs_server_timeout = 10;	/* server timeout in seconds */
+static unsigned afs_server_gc_delay = 10;	/* Server record timeout in seconds */
+static atomic_t afs_server_debug_id;
 
-static void afs_reap_server(struct work_struct *);
+static void __afs_put_server(struct afs_net *, struct afs_server *);
+static void afs_server_timer(struct timer_list *timer);
+static void afs_server_destroyer(struct work_struct *work);
 
-/* tree of all the servers, indexed by IP address */
-static struct rb_root afs_servers = RB_ROOT;
-static DEFINE_RWLOCK(afs_servers_lock);
+/*
+ * Find a server by one of its addresses.
+ */
+struct afs_server *afs_find_server(const struct rxrpc_peer *peer)
+{
+	struct afs_server *server = (struct afs_server *)rxrpc_kernel_get_peer_data(peer);
 
-/* LRU list of all the servers not currently in use */
-static LIST_HEAD(afs_server_graveyard);
-static DEFINE_SPINLOCK(afs_server_graveyard_lock);
-static DECLARE_DELAYED_WORK(afs_server_reaper, afs_reap_server);
+	if (!server)
+		return NULL;
+	return afs_use_server(server, false, afs_server_trace_use_cm_call);
+}
 
 /*
- * install a server record in the master tree
+ * Look up a server by its UUID and mark it active.  The caller must hold
+ * cell->fs_lock.
  */
-static int afs_install_server(struct afs_server *server)
+static struct afs_server *afs_find_server_by_uuid(struct afs_cell *cell, const uuid_t *uuid)
 {
-	struct afs_server *xserver;
-	struct rb_node **pp, *p;
-	int ret;
+	struct afs_server *server;
+	struct rb_node *p;
+	int diff;
 
-	_enter("%p", server);
+	_enter("%pU", uuid);
 
-	write_lock(&afs_servers_lock);
+	p = cell->fs_servers.rb_node;
+	while (p) {
+		server = rb_entry(p, struct afs_server, uuid_rb);
 
-	ret = -EEXIST;
-	pp = &afs_servers.rb_node;
+		diff = memcmp(uuid, &server->uuid, sizeof(*uuid));
+		if (diff < 0) {
+			p = p->rb_left;
+		} else if (diff > 0) {
+			p = p->rb_right;
+		} else {
+			if (test_bit(AFS_SERVER_FL_UNCREATED, &server->flags))
+				return NULL; /* Need a write lock */
+			afs_use_server(server, true, afs_server_trace_use_by_uuid);
+			return server;
+		}
+	}
+
+	return NULL;
+}
+
+/*
+ * Install a server record in the cell tree.  The caller must hold an exclusive
+ * lock on cell->fs_lock.
+ */
+static struct afs_server *afs_install_server(struct afs_cell *cell,
+					     struct afs_server **candidate)
+{
+	struct afs_server *server;
+	struct afs_net *net = cell->net;
+	struct rb_node **pp, *p;
+	int diff;
+
+	_enter("%p", candidate);
+
+	/* Firstly install the server in the UUID lookup tree */
+	pp = &cell->fs_servers.rb_node;
 	p = NULL;
 	while (*pp) {
 		p = *pp;
 		_debug("- consider %p", p);
-		xserver = rb_entry(p, struct afs_server, master_rb);
-		if (server->addr.s_addr < xserver->addr.s_addr)
+		server = rb_entry(p, struct afs_server, uuid_rb);
+		diff = memcmp(&(*candidate)->uuid, &server->uuid, sizeof(uuid_t));
+		if (diff < 0)
 			pp = &(*pp)->rb_left;
-		else if (server->addr.s_addr > xserver->addr.s_addr)
+		else if (diff > 0)
 			pp = &(*pp)->rb_right;
 		else
-			goto error;
+			goto exists;
 	}
 
-	rb_link_node(&server->master_rb, p, pp);
-	rb_insert_color(&server->master_rb, &afs_servers);
-	ret = 0;
+	server = *candidate;
+	*candidate = NULL;
+	rb_link_node(&server->uuid_rb, p, pp);
+	rb_insert_color(&server->uuid_rb, &cell->fs_servers);
+	write_seqlock(&net->fs_lock);
+	hlist_add_head_rcu(&server->proc_link, &net->fs_proc);
+	write_sequnlock(&net->fs_lock);
+
+	afs_get_cell(cell, afs_cell_trace_get_server);
 
-error:
-	write_unlock(&afs_servers_lock);
-	return ret;
+exists:
+	afs_use_server(server, true, afs_server_trace_use_install);
+	return server;
 }
 
 /*
- * allocate a new server record
+ * Allocate a new server record and mark it as active but uncreated.
  */
-static struct afs_server *afs_alloc_server(struct afs_cell *cell,
-					   const struct in_addr *addr)
+static struct afs_server *afs_alloc_server(struct afs_cell *cell, const uuid_t *uuid)
 {
 	struct afs_server *server;
+	struct afs_net *net = cell->net;
 
 	_enter("");
 
 	server = kzalloc(sizeof(struct afs_server), GFP_KERNEL);
-	if (server) {
-		atomic_set(&server->usage, 1);
-		server->cell = cell;
-
-		INIT_LIST_HEAD(&server->link);
-		INIT_LIST_HEAD(&server->grave);
-		init_rwsem(&server->sem);
-		spin_lock_init(&server->fs_lock);
-		server->fs_vnodes = RB_ROOT;
-		server->cb_promises = RB_ROOT;
-		spin_lock_init(&server->cb_lock);
-		init_waitqueue_head(&server->cb_break_waitq);
-		INIT_DELAYED_WORK(&server->cb_break_work,
-				  afs_dispatch_give_up_callbacks);
-
-		memcpy(&server->addr, addr, sizeof(struct in_addr));
-		server->addr.s_addr = addr->s_addr;
-		_leave(" = %p{%d}", server, atomic_read(&server->usage));
-	} else {
-		_leave(" = NULL [nomem]");
-	}
+	if (!server)
+		return NULL;
+
+	refcount_set(&server->ref, 1);
+	atomic_set(&server->active, 0);
+	__set_bit(AFS_SERVER_FL_UNCREATED, &server->flags);
+	server->debug_id = atomic_inc_return(&afs_server_debug_id);
+	server->uuid = *uuid;
+	rwlock_init(&server->fs_lock);
+	INIT_WORK(&server->destroyer, &afs_server_destroyer);
+	timer_setup(&server->timer, afs_server_timer, 0);
+	INIT_LIST_HEAD(&server->volumes);
+	init_waitqueue_head(&server->probe_wq);
+	mutex_init(&server->cm_token_lock);
+	INIT_LIST_HEAD(&server->probe_link);
+	INIT_HLIST_NODE(&server->proc_link);
+	spin_lock_init(&server->probe_lock);
+	server->cell = cell;
+	server->rtt = UINT_MAX;
+	server->service_id = FS_SERVICE;
+	server->probe_counter = 1;
+	server->probed_at = jiffies - LONG_MAX / 2;
+
+	afs_inc_servers_outstanding(net);
+	_leave(" = %p", server);
 	return server;
 }
 
 /*
- * get an FS-server record for a cell
+ * Look up an address record for a server
  */
-struct afs_server *afs_lookup_server(struct afs_cell *cell,
-				     const struct in_addr *addr)
+static struct afs_addr_list *afs_vl_lookup_addrs(struct afs_server *server,
+						 struct key *key)
 {
-	struct afs_server *server, *candidate;
+	struct afs_vl_cursor vc;
+	struct afs_addr_list *alist = NULL;
+	int ret;
+
+	ret = -ERESTARTSYS;
+	if (afs_begin_vlserver_operation(&vc, server->cell, key)) {
+		while (afs_select_vlserver(&vc)) {
+			if (test_bit(AFS_VLSERVER_FL_IS_YFS, &vc.server->flags))
+				alist = afs_yfsvl_get_endpoints(&vc, &server->uuid);
+			else
+				alist = afs_vl_get_addrs_u(&vc, &server->uuid);
+		}
 
-	_enter("%p,%pI4", cell, &addr->s_addr);
+		ret = afs_end_vlserver_operation(&vc);
+	}
 
-	/* quick scan of the list to see if we already have the server */
-	read_lock(&cell->servers_lock);
+	return ret < 0 ? ERR_PTR(ret) : alist;
+}
 
-	list_for_each_entry(server, &cell->servers, link) {
-		if (server->addr.s_addr == addr->s_addr)
-			goto found_server_quickly;
+/*
+ * Get or create a fileserver record and return it with an active-use count on
+ * it.
+ */
+struct afs_server *afs_lookup_server(struct afs_cell *cell, struct key *key,
+				     const uuid_t *uuid, u32 addr_version)
+{
+	struct afs_addr_list *alist = NULL;
+	struct afs_server *server, *candidate = NULL;
+	bool creating = false;
+	int ret;
+
+	_enter("%p,%pU", cell->net, uuid);
+
+	down_read(&cell->fs_lock);
+	server = afs_find_server_by_uuid(cell, uuid);
+	/* Won't see servers marked uncreated. */
+	up_read(&cell->fs_lock);
+
+	if (server) {
+		timer_delete_sync(&server->timer);
+		if (test_bit(AFS_SERVER_FL_CREATING, &server->flags))
+			goto wait_for_creation;
+		if (server->addr_version != addr_version)
+			set_bit(AFS_SERVER_FL_NEEDS_UPDATE, &server->flags);
+		return server;
 	}
-	read_unlock(&cell->servers_lock);
 
-	candidate = afs_alloc_server(cell, addr);
+	candidate = afs_alloc_server(cell, uuid);
 	if (!candidate) {
-		_leave(" = -ENOMEM");
+		afs_put_addrlist(alist, afs_alist_trace_put_server_oom);
 		return ERR_PTR(-ENOMEM);
 	}
 
-	write_lock(&cell->servers_lock);
+	down_write(&cell->fs_lock);
+	server = afs_install_server(cell, &candidate);
+	if (test_bit(AFS_SERVER_FL_CREATING, &server->flags)) {
+		/* We need to wait for creation to complete. */
+		up_write(&cell->fs_lock);
+		goto wait_for_creation;
+	}
+	if (test_bit(AFS_SERVER_FL_UNCREATED, &server->flags)) {
+		set_bit(AFS_SERVER_FL_CREATING, &server->flags);
+		clear_bit(AFS_SERVER_FL_UNCREATED, &server->flags);
+		creating = true;
+	}
+	up_write(&cell->fs_lock);
+	timer_delete_sync(&server->timer);
+
+	/* If we get to create the server, we look up the addresses and then
+	 * immediately dispatch an asynchronous probe to each interface on the
+	 * fileserver.  This will make sure the repeat-probing service is
+	 * started.
+	 */
+	if (creating) {
+		alist = afs_vl_lookup_addrs(server, key);
+		if (IS_ERR(alist)) {
+			ret = PTR_ERR(alist);
+			goto create_failed;
+		}
+
+		ret = afs_fs_probe_fileserver(cell->net, server, alist, key);
+		if (ret)
+			goto create_failed;
+
+		clear_and_wake_up_bit(AFS_SERVER_FL_CREATING, &server->flags);
+	}
 
-	/* check the cell's server list again */
-	list_for_each_entry(server, &cell->servers, link) {
-		if (server->addr.s_addr == addr->s_addr)
-			goto found_server;
+out:
+	afs_put_addrlist(alist, afs_alist_trace_put_server_create);
+	if (candidate) {
+		kfree(rcu_access_pointer(server->endpoint_state));
+		kfree(candidate);
+		afs_dec_servers_outstanding(cell->net);
+	}
+	return server ?: ERR_PTR(ret);
+
+wait_for_creation:
+	afs_see_server(server, afs_server_trace_wait_create);
+	wait_on_bit(&server->flags, AFS_SERVER_FL_CREATING, TASK_UNINTERRUPTIBLE);
+	if (test_bit_acquire(AFS_SERVER_FL_UNCREATED, &server->flags)) {
+		/* Barrier: read flag before error */
+		ret = READ_ONCE(server->create_error);
+		afs_put_server(cell->net, server, afs_server_trace_unuse_create_fail);
+		server = NULL;
+		goto out;
 	}
 
-	_debug("new");
-	server = candidate;
-	if (afs_install_server(server) < 0)
-		goto server_in_two_cells;
+	ret = 0;
+	goto out;
 
-	afs_get_cell(cell);
-	list_add_tail(&server->link, &cell->servers);
+create_failed:
+	down_write(&cell->fs_lock);
 
-	write_unlock(&cell->servers_lock);
-	_leave(" = %p{%d}", server, atomic_read(&server->usage));
-	return server;
+	WRITE_ONCE(server->create_error, ret);
+	smp_wmb(); /* Barrier: set error before flag. */
+	set_bit(AFS_SERVER_FL_UNCREATED, &server->flags);
+
+	clear_and_wake_up_bit(AFS_SERVER_FL_CREATING, &server->flags);
 
-	/* found a matching server quickly */
-found_server_quickly:
-	_debug("found quickly");
-	afs_get_server(server);
-	read_unlock(&cell->servers_lock);
-no_longer_unused:
-	if (!list_empty(&server->grave)) {
-		spin_lock(&afs_server_graveyard_lock);
-		list_del_init(&server->grave);
-		spin_unlock(&afs_server_graveyard_lock);
+	if (test_bit(AFS_SERVER_FL_UNCREATED, &server->flags)) {
+		clear_bit(AFS_SERVER_FL_UNCREATED, &server->flags);
+		creating = true;
 	}
-	_leave(" = %p{%d}", server, atomic_read(&server->usage));
-	return server;
+	afs_unuse_server(cell->net, server, afs_server_trace_unuse_create_fail);
+	server = NULL;
 
-	/* found a matching server on the second pass */
-found_server:
-	_debug("found");
-	afs_get_server(server);
-	write_unlock(&cell->servers_lock);
-	kfree(candidate);
-	goto no_longer_unused;
-
-	/* found a server that seems to be in two cells */
-server_in_two_cells:
-	write_unlock(&cell->servers_lock);
-	kfree(candidate);
-	printk(KERN_NOTICE "kAFS: Server %pI4 appears to be in two cells\n",
-	       addr);
-	_leave(" = -EEXIST");
-	return ERR_PTR(-EEXIST);
+	up_write(&cell->fs_lock);
+	goto out;
 }
 
 /*
- * look up a server by its IP address
+ * Set/reduce a server's timer.
  */
-struct afs_server *afs_find_server(const struct in_addr *_addr)
+static void afs_set_server_timer(struct afs_server *server, unsigned int delay_secs)
 {
-	struct afs_server *server = NULL;
-	struct rb_node *p;
-	struct in_addr addr = *_addr;
-
-	_enter("%pI4", &addr.s_addr);
+	mod_timer(&server->timer, jiffies + delay_secs * HZ);
+}
 
-	read_lock(&afs_servers_lock);
+/*
+ * Get a reference on a server object.
+ */
+struct afs_server *afs_get_server(struct afs_server *server,
+				  enum afs_server_trace reason)
+{
+	unsigned int a;
+	int r;
 
-	p = afs_servers.rb_node;
-	while (p) {
-		server = rb_entry(p, struct afs_server, master_rb);
+	__refcount_inc(&server->ref, &r);
+	a = atomic_read(&server->active);
+	trace_afs_server(server->debug_id, r + 1, a, reason);
+	return server;
+}
 
-		_debug("- consider %p", p);
+/*
+ * Get an active count on a server object and maybe remove from the inactive
+ * list.
+ */
+struct afs_server *afs_use_server(struct afs_server *server, bool activate,
+				  enum afs_server_trace reason)
+{
+	unsigned int a;
+	int r;
 
-		if (addr.s_addr < server->addr.s_addr) {
-			p = p->rb_left;
-		} else if (addr.s_addr > server->addr.s_addr) {
-			p = p->rb_right;
-		} else {
-			afs_get_server(server);
-			goto found;
-		}
-	}
+	__refcount_inc(&server->ref, &r);
+	a = atomic_inc_return(&server->active);
+	if (a == 1 && activate &&
+	    !test_bit(AFS_SERVER_FL_EXPIRED, &server->flags))
+		timer_delete(&server->timer);
 
-	server = NULL;
-found:
-	read_unlock(&afs_servers_lock);
-	ASSERTIFCMP(server, server->addr.s_addr, ==, addr.s_addr);
-	_leave(" = %p", server);
+	trace_afs_server(server->debug_id, r + 1, a, reason);
 	return server;
 }
 
 /*
- * destroy a server record
- * - removes from the cell list
+ * Release a reference on a server record.
  */
-void afs_put_server(struct afs_server *server)
+void afs_put_server(struct afs_net *net, struct afs_server *server,
+		    enum afs_server_trace reason)
 {
+	unsigned int a, debug_id;
+	bool zero;
+	int r;
+
 	if (!server)
 		return;
 
-	_enter("%p{%d}", server, atomic_read(&server->usage));
+	debug_id = server->debug_id;
+	a = atomic_read(&server->active);
+	zero = __refcount_dec_and_test(&server->ref, &r);
+	trace_afs_server(debug_id, r - 1, a, reason);
+	if (unlikely(zero))
+		__afs_put_server(net, server);
+}
 
-	_debug("PUT SERVER %d", atomic_read(&server->usage));
+/*
+ * 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)
+		return;
+
+	if (atomic_dec_and_test(&server->active)) {
+		if (test_bit(AFS_SERVER_FL_EXPIRED, &server->flags) ||
+		    READ_ONCE(server->cell->state) >= AFS_CELL_REMOVING)
+			schedule_work(&server->destroyer);
+	}
 
-	ASSERTCMP(atomic_read(&server->usage), >, 0);
+	afs_put_server(net, server, reason);
+}
 
-	if (likely(!atomic_dec_and_test(&server->usage))) {
-		_leave("");
+/*
+ * 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)
 		return;
+
+	if (atomic_dec_and_test(&server->active)) {
+		if (!test_bit(AFS_SERVER_FL_EXPIRED, &server->flags) &&
+		    READ_ONCE(server->cell->state) < AFS_CELL_REMOVING) {
+			time64_t unuse_time = ktime_get_real_seconds();
+
+			server->unuse_time = unuse_time;
+			afs_set_server_timer(server, afs_server_gc_delay);
+		} else {
+			schedule_work(&server->destroyer);
+		}
 	}
 
-	afs_flush_callback_breaks(server);
+	afs_put_server(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->debug_id, refcount_read(&server->ref),
+			 atomic_read(&server->active), afs_server_trace_free);
+	afs_put_endpoint_state(rcu_access_pointer(server->endpoint_state),
+			       afs_estate_trace_put_server);
+	afs_put_cell(server->cell, afs_cell_trace_put_server);
+	kfree(server->cm_rxgk_appdata.data);
+	kfree(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_endpoint_state *estate = rcu_access_pointer(server->endpoint_state);
+	struct afs_addr_list *alist = estate->addresses;
+
+	afs_fs_give_up_all_callbacks(net, server, &alist->addrs[alist->preferred], NULL);
+}
+
+/*
+ * Check to see if the server record has expired.
+ */
+static bool afs_has_server_expired(const struct afs_server *server)
+{
+	time64_t expires_at;
+
+	if (atomic_read(&server->active))
+		return false;
 
-	spin_lock(&afs_server_graveyard_lock);
-	if (atomic_read(&server->usage) == 0) {
-		list_move_tail(&server->grave, &afs_server_graveyard);
-		server->time_of_death = get_seconds();
-		queue_delayed_work(afs_wq, &afs_server_reaper,
-				   afs_server_timeout * HZ);
+	if (server->cell->net->live ||
+	    server->cell->state >= AFS_CELL_REMOVING) {
+		trace_afs_server(server->debug_id, refcount_read(&server->ref),
+				 0, afs_server_trace_purging);
+		return true;
 	}
-	spin_unlock(&afs_server_graveyard_lock);
-	_leave(" [dead]");
+
+	expires_at = server->unuse_time;
+	if (!test_bit(AFS_SERVER_FL_VL_FAIL, &server->flags) &&
+	    !test_bit(AFS_SERVER_FL_NOT_FOUND, &server->flags))
+		expires_at += afs_server_gc_delay;
+
+	return ktime_get_real_seconds() > expires_at;
 }
 
 /*
- * destroy a dead server
+ * Remove a server record from it's parent cell's database.
  */
-static void afs_destroy_server(struct afs_server *server)
+static bool afs_remove_server_from_cell(struct afs_server *server)
 {
-	_enter("%p", server);
+	struct afs_cell *cell = server->cell;
+
+	down_write(&cell->fs_lock);
 
-	ASSERTIF(server->cb_break_head != server->cb_break_tail,
-		 delayed_work_pending(&server->cb_break_work));
+	if (!afs_has_server_expired(server)) {
+		up_write(&cell->fs_lock);
+		return false;
+	}
 
-	ASSERTCMP(server->fs_vnodes.rb_node, ==, NULL);
-	ASSERTCMP(server->cb_promises.rb_node, ==, NULL);
-	ASSERTCMP(server->cb_break_head, ==, server->cb_break_tail);
-	ASSERTCMP(atomic_read(&server->cb_break_n), ==, 0);
+	set_bit(AFS_SERVER_FL_EXPIRED, &server->flags);
+	_debug("expire %pU %u", &server->uuid, atomic_read(&server->active));
+	afs_see_server(server, afs_server_trace_see_expired);
+	rb_erase(&server->uuid_rb, &cell->fs_servers);
+	up_write(&cell->fs_lock);
+	return true;
+}
 
-	afs_put_cell(server->cell);
-	kfree(server);
+static void afs_server_destroyer(struct work_struct *work)
+{
+	struct afs_endpoint_state *estate;
+	struct afs_server *server = container_of(work, struct afs_server, destroyer);
+	struct afs_net *net = server->cell->net;
+
+	afs_see_server(server, afs_server_trace_see_destroyer);
+
+	if (test_bit(AFS_SERVER_FL_EXPIRED, &server->flags))
+		return;
+
+	if (!afs_remove_server_from_cell(server))
+		return;
+
+	timer_shutdown_sync(&server->timer);
+	cancel_work(&server->destroyer);
+
+	if (test_bit(AFS_SERVER_FL_MAY_HAVE_CB, &server->flags))
+		afs_give_up_callbacks(net, server);
+
+	/* Unbind the rxrpc_peer records from the server. */
+	estate = rcu_access_pointer(server->endpoint_state);
+	if (estate)
+		afs_set_peer_appdata(server, estate->addresses, NULL);
+
+	write_seqlock(&net->fs_lock);
+	list_del_init(&server->probe_link);
+	if (!hlist_unhashed(&server->proc_link))
+		hlist_del_rcu(&server->proc_link);
+	write_sequnlock(&net->fs_lock);
+
+	afs_put_server(net, server, afs_server_trace_destroy);
+}
+
+static void afs_server_timer(struct timer_list *timer)
+{
+	struct afs_server *server = container_of(timer, struct afs_server, timer);
+
+	afs_see_server(server, afs_server_trace_see_timer);
+	if (!test_bit(AFS_SERVER_FL_EXPIRED, &server->flags))
+		schedule_work(&server->destroyer);
 }
 
 /*
- * reap dead server records
+ * Wake up all the servers in a cell so that they can purge themselves.
  */
-static void afs_reap_server(struct work_struct *work)
+void afs_purge_servers(struct afs_cell *cell)
 {
-	LIST_HEAD(corpses);
 	struct afs_server *server;
-	unsigned long delay, expiry;
-	time_t now;
-
-	now = get_seconds();
-	spin_lock(&afs_server_graveyard_lock);
-
-	while (!list_empty(&afs_server_graveyard)) {
-		server = list_entry(afs_server_graveyard.next,
-				    struct afs_server, grave);
-
-		/* the queue is ordered most dead first */
-		expiry = server->time_of_death + afs_server_timeout;
-		if (expiry > now) {
-			delay = (expiry - now) * HZ;
-			mod_delayed_work(afs_wq, &afs_server_reaper, delay);
-			break;
-		}
+	struct rb_node *rb;
 
-		write_lock(&server->cell->servers_lock);
-		write_lock(&afs_servers_lock);
-		if (atomic_read(&server->usage) > 0) {
-			list_del_init(&server->grave);
-		} else {
-			list_move_tail(&server->grave, &corpses);
-			list_del_init(&server->link);
-			rb_erase(&server->master_rb, &afs_servers);
-		}
-		write_unlock(&afs_servers_lock);
-		write_unlock(&server->cell->servers_lock);
+	down_read(&cell->fs_lock);
+	for (rb = rb_first(&cell->fs_servers); rb; rb = rb_next(rb)) {
+		server = rb_entry(rb, struct afs_server, uuid_rb);
+		afs_see_server(server, afs_server_trace_see_purge);
+		schedule_work(&server->destroyer);
 	}
+	up_read(&cell->fs_lock);
+}
+
+/*
+ * Wait for outstanding servers.
+ */
+void afs_wait_for_servers(struct afs_net *net)
+{
+	_enter("");
+
+	atomic_dec(&net->servers_outstanding);
+	wait_var_event(&net->servers_outstanding,
+		       !atomic_read(&net->servers_outstanding));
+	_leave("");
+}
+
+/*
+ * Get an update for a server's address list.
+ */
+static noinline bool afs_update_server_record(struct afs_operation *op,
+					      struct afs_server *server,
+					      struct key *key)
+{
+	struct afs_endpoint_state *estate;
+	struct afs_addr_list *alist;
+	bool has_addrs;
 
-	spin_unlock(&afs_server_graveyard_lock);
+	_enter("");
 
-	/* now reap the corpses we've extracted */
-	while (!list_empty(&corpses)) {
-		server = list_entry(corpses.next, struct afs_server, grave);
-		list_del(&server->grave);
-		afs_destroy_server(server);
+	trace_afs_server(server->debug_id, refcount_read(&server->ref),
+			 atomic_read(&server->active),
+			 afs_server_trace_update);
+
+	alist = afs_vl_lookup_addrs(server, op->key);
+	if (IS_ERR(alist)) {
+		rcu_read_lock();
+		estate = rcu_dereference(server->endpoint_state);
+		has_addrs = estate->addresses;
+		rcu_read_unlock();
+
+		if ((PTR_ERR(alist) == -ERESTARTSYS ||
+		     PTR_ERR(alist) == -EINTR) &&
+		    (op->flags & AFS_OPERATION_UNINTR) &&
+		    has_addrs) {
+			_leave(" = t [intr]");
+			return true;
+		}
+		afs_op_set_error(op, PTR_ERR(alist));
+		_leave(" = f [%d]", afs_op_error(op));
+		return false;
 	}
+
+	if (server->addr_version != alist->version)
+		afs_fs_probe_fileserver(op->net, server, alist, key);
+
+	afs_put_addrlist(alist, afs_alist_trace_put_server_update);
+	_leave(" = t");
+	return true;
 }
 
 /*
- * discard all the server records for rmmod
+ * See if a server's address list needs updating.
  */
-void __exit afs_purge_servers(void)
+bool afs_check_server_record(struct afs_operation *op, struct afs_server *server,
+			     struct key *key)
 {
-	afs_server_timeout = 0;
-	mod_delayed_work(afs_wq, &afs_server_reaper, 0);
+	bool success;
+	int ret, retries = 0;
+
+	_enter("");
+
+	ASSERT(server);
+
+retry:
+	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)) {
+		clear_bit(AFS_SERVER_FL_NEEDS_UPDATE, &server->flags);
+		success = afs_update_server_record(op, server, key);
+		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,
+			  (op->flags & AFS_OPERATION_UNINTR) ?
+			  TASK_UNINTERRUPTIBLE : TASK_INTERRUPTIBLE);
+	if (ret == -ERESTARTSYS) {
+		afs_op_set_error(op, ret);
+		_leave(" = f [intr]");
+		return false;
+	}
+
+	retries++;
+	if (retries == 4) {
+		_leave(" = f [stale]");
+		ret = -ESTALE;
+		return false;
+	}
+	goto retry;
 }