~hc/RK356X_SDK_RELEASE.git

..	..	@@ -1,12 +1,8 @@
	1	+// SPDX-License-Identifier: GPL-2.0-or-later
1	2	/* AFS cell and server record management
2	3	*
3	4	* Copyright (C) 2002, 2017 Red Hat, Inc. All Rights Reserved.
4	5	* Written by David Howells (dhowells@redhat.com)
5		- *
6		- * This program is free software; you can redistribute it and/or
7		- * modify it under the terms of the GNU General Public License
8		- * as published by the Free Software Foundation; either version
9		- * 2 of the License, or (at your option) any later version.
10	6	*/
11	7
12	8	#include <linux/slab.h>
..	..	@@ -20,8 +16,12 @@
20	16	#include "internal.h"
21	17
22	18	static unsigned __read_mostly afs_cell_gc_delay = 10;
	19	+static unsigned __read_mostly afs_cell_min_ttl = 10 * 60;
	20	+static unsigned __read_mostly afs_cell_max_ttl = 24 * 60 * 60;
	21	+static atomic_t cell_debug_id;
23	22
24		-static void afs_manage_cell(struct work_struct *);
	23	+static void afs_queue_cell_manager(struct afs_net *);
	24	+static void afs_manage_cell_work(struct work_struct *);
25	25
26	26	static void afs_dec_cells_outstanding(struct afs_net *net)
27	27	{
..	..	@@ -39,19 +39,22 @@
39	39	atomic_inc(&net->cells_outstanding);
40	40	if (timer_reduce(&net->cells_timer, jiffies + delay * HZ))
41	41	afs_dec_cells_outstanding(net);
	42	+ } else {
	43	+ afs_queue_cell_manager(net);
42	44	}
43	45	}
44	46
45	47	/*
46		- * Look up and get an activation reference on a cell record under RCU
47		- * conditions. The caller must hold the RCU read lock.
	48	+ * Look up and get an activation reference on a cell record. The caller must
	49	+ * hold net->cells_lock at least read-locked.
48	50	*/
49		-struct afs_cell afs_lookup_cell_rcu(struct afs_net net,
50		- const char *name, unsigned int namesz)
	51	+static struct afs_cell afs_find_cell_locked(struct afs_net net,
	52	+ const char *name, unsigned int namesz,
	53	+ enum afs_cell_trace reason)
51	54	{
52	55	struct afs_cell *cell = NULL;
53	56	struct rb_node *p;
54		- int n, seq = 0, ret = 0;
	57	+ int n;
55	58
56	59	_enter("%.s", namesz, namesz, name);
57	60
..	..	@@ -60,61 +63,48 @@
60	63	if (namesz > AFS_MAXCELLNAME)
61	64	return ERR_PTR(-ENAMETOOLONG);
62	65
63		- do {
64		- /* Unfortunately, rbtree walking doesn't give reliable results
65		- * under just the RCU read lock, so we have to check for
66		- * changes.
67		- */
68		- if (cell)
69		- afs_put_cell(net, cell);
70		- cell = NULL;
71		- ret = -ENOENT;
	66	+ if (!name) {
	67	+ cell = net->ws_cell;
	68	+ if (!cell)
	69	+ return ERR_PTR(-EDESTADDRREQ);
	70	+ goto found;
	71	+ }
72	72
73		- read_seqbegin_or_lock(&net->cells_lock, &seq);
	73	+ p = net->cells.rb_node;
	74	+ while (p) {
	75	+ cell = rb_entry(p, struct afs_cell, net_node);
74	76
75		- if (!name) {
76		- cell = rcu_dereference_raw(net->ws_cell);
77		- if (cell) {
78		- afs_get_cell(cell);
79		- ret = 0;
80		- break;
81		- }
82		- ret = -EDESTADDRREQ;
83		- continue;
84		- }
	77	+ n = strncasecmp(cell->name, name,
	78	+ min_t(size_t, cell->name_len, namesz));
	79	+ if (n == 0)
	80	+ n = cell->name_len - namesz;
	81	+ if (n < 0)
	82	+ p = p->rb_left;
	83	+ else if (n > 0)
	84	+ p = p->rb_right;
	85	+ else
	86	+ goto found;
	87	+ }
85	88
86		- p = rcu_dereference_raw(net->cells.rb_node);
87		- while (p) {
88		- cell = rb_entry(p, struct afs_cell, net_node);
	89	+ return ERR_PTR(-ENOENT);
89	90
90		- n = strncasecmp(cell->name, name,
91		- min_t(size_t, cell->name_len, namesz));
92		- if (n == 0)
93		- n = cell->name_len - namesz;
94		- if (n < 0) {
95		- p = rcu_dereference_raw(p->rb_left);
96		- } else if (n > 0) {
97		- p = rcu_dereference_raw(p->rb_right);
98		- } else {
99		- if (atomic_inc_not_zero(&cell->usage)) {
100		- ret = 0;
101		- break;
102		- }
103		- /* We want to repeat the search, this time with
104		- * the lock properly locked.
105		- */
106		- }
107		- cell = NULL;
108		- }
	91	+found:
	92	+ return afs_use_cell(cell, reason);
	93	+}
109	94
110		- } while (need_seqretry(&net->cells_lock, seq));
	95	+/*
	96	+ * Look up and get an activation reference on a cell record.
	97	+ */
	98	+struct afs_cell afs_find_cell(struct afs_net net,
	99	+ const char *name, unsigned int namesz,
	100	+ enum afs_cell_trace reason)
	101	+{
	102	+ struct afs_cell *cell;
111	103
112		- done_seqretry(&net->cells_lock, seq);
113		-
114		- if (ret != 0 && cell)
115		- afs_put_cell(net, cell);
116		-
117		- return ret == 0 ? cell : ERR_PTR(ret);
	104	+ down_read(&net->cells_lock);
	105	+ cell = afs_find_cell_locked(net, name, namesz, reason);
	106	+ up_read(&net->cells_lock);
	107	+ return cell;
118	108	}
119	109
120	110	/*
..	..	@@ -123,8 +113,9 @@
123	113	*/
124	114	static struct afs_cell afs_alloc_cell(struct afs_net net,
125	115	const char *name, unsigned int namelen,
126		- const char *vllist)
	116	+ const char *addresses)
127	117	{
	118	+ struct afs_vlserver_list *vllist;
128	119	struct afs_cell *cell;
129	120	int i, ret;
130	121
..	..	@@ -147,7 +138,7 @@
147	138	return ERR_PTR(-EINVAL);
148	139	}
149	140
150		- _enter("%.s,%s", namelen, namelen, name, vllist);
	141	+ _enter("%.s,%s", namelen, namelen, name, addresses);
151	142
152	143	cell = kzalloc(sizeof(struct afs_cell), GFP_KERNEL);
153	144	if (!cell) {
..	..	@@ -155,35 +146,62 @@
155	146	return ERR_PTR(-ENOMEM);
156	147	}
157	148
	149	+ cell->name = kmalloc(namelen + 1, GFP_KERNEL);
	150	+ if (!cell->name) {
	151	+ kfree(cell);
	152	+ return ERR_PTR(-ENOMEM);
	153	+ }
	154	+
158	155	cell->net = net;
159	156	cell->name_len = namelen;
160	157	for (i = 0; i < namelen; i++)
161	158	cell->name[i] = tolower(name[i]);
	159	+ cell->name[i] = 0;
162	160
163		- atomic_set(&cell->usage, 2);
164		- INIT_WORK(&cell->manager, afs_manage_cell);
165		- cell->flags = ((1 << AFS_CELL_FL_NOT_READY) \|
166		- (1 << AFS_CELL_FL_NO_LOOKUP_YET));
167		- INIT_LIST_HEAD(&cell->proc_volumes);
168		- rwlock_init(&cell->proc_lock);
169		- rwlock_init(&cell->vl_addrs_lock);
	161	+ atomic_set(&cell->ref, 1);
	162	+ atomic_set(&cell->active, 0);
	163	+ INIT_WORK(&cell->manager, afs_manage_cell_work);
	164	+ cell->volumes = RB_ROOT;
	165	+ INIT_HLIST_HEAD(&cell->proc_volumes);
	166	+ seqlock_init(&cell->volume_lock);
	167	+ cell->fs_servers = RB_ROOT;
	168	+ seqlock_init(&cell->fs_lock);
	169	+ rwlock_init(&cell->vl_servers_lock);
	170	+ cell->flags = (1 << AFS_CELL_FL_CHECK_ALIAS);
170	171
171		- /* Fill in the VL server list if we were given a list of addresses to
172		- * use.
	172	+ /* Provide a VL server list, filling it in if we were given a list of
	173	+ * addresses to use.
173	174	*/
174		- if (vllist) {
175		- struct afs_addr_list *alist;
176		-
177		- alist = afs_parse_text_addrs(vllist, strlen(vllist), ':',
178		- VL_SERVICE, AFS_VL_PORT);
179		- if (IS_ERR(alist)) {
180		- ret = PTR_ERR(alist);
	175	+ if (addresses) {
	176	+ vllist = afs_parse_text_addrs(net,
	177	+ addresses, strlen(addresses), ':',
	178	+ VL_SERVICE, AFS_VL_PORT);
	179	+ if (IS_ERR(vllist)) {
	180	+ ret = PTR_ERR(vllist);
181	181	goto parse_failed;
182	182	}
183	183
184		- rcu_assign_pointer(cell->vl_addrs, alist);
	184	+ vllist->source = DNS_RECORD_FROM_CONFIG;
	185	+ vllist->status = DNS_LOOKUP_NOT_DONE;
185	186	cell->dns_expiry = TIME64_MAX;
	187	+ } else {
	188	+ ret = -ENOMEM;
	189	+ vllist = afs_alloc_vlserver_list(0);
	190	+ if (!vllist)
	191	+ goto error;
	192	+ vllist->source = DNS_RECORD_UNAVAILABLE;
	193	+ vllist->status = DNS_LOOKUP_NOT_DONE;
	194	+ cell->dns_expiry = ktime_get_real_seconds();
186	195	}
	196	+
	197	+ rcu_assign_pointer(cell->vl_servers, vllist);
	198	+
	199	+ cell->dns_source = vllist->source;
	200	+ cell->dns_status = vllist->status;
	201	+ smp_store_release(&cell->dns_lookup_count, 1); /* vs source/status */
	202	+ atomic_inc(&net->cells_outstanding);
	203	+ cell->debug_id = atomic_inc_return(&cell_debug_id);
	204	+ trace_afs_cell(cell->debug_id, 1, 0, afs_cell_trace_alloc);
187	205
188	206	_leave(" = %p", cell);
189	207	return cell;
..	..	@@ -191,6 +209,8 @@
191	209	parse_failed:
192	210	if (ret == -EINVAL)
193	211	printk(KERN_ERR "kAFS: bad VL server IP address\n");
	212	+error:
	213	+ kfree(cell->name);
194	214	kfree(cell);
195	215	_leave(" = %d", ret);
196	216	return ERR_PTR(ret);
..	..	@@ -215,14 +235,13 @@
215	235	{
216	236	struct afs_cell cell, candidate, *cursor;
217	237	struct rb_node parent, *pp;
	238	+ enum afs_cell_state state;
218	239	int ret, n;
219	240
220	241	_enter("%s,%s", name, vllist);
221	242
222	243	if (!excl) {
223		- rcu_read_lock();
224		- cell = afs_lookup_cell_rcu(net, name, namesz);
225		- rcu_read_unlock();
	244	+ cell = afs_find_cell(net, name, namesz, afs_cell_trace_use_lookup);
226	245	if (!IS_ERR(cell))
227	246	goto wait_for_cell;
228	247	}
..	..	@@ -243,7 +262,7 @@
243	262	/* Find the insertion point and check to see if someone else added a
244	263	* cell whilst we were allocating.
245	264	*/
246		- write_seqlock(&net->cells_lock);
	265	+ down_write(&net->cells_lock);
247	266
248	267	pp = &net->cells.rb_node;
249	268	parent = NULL;
..	..	@@ -265,27 +284,28 @@
265	284
266	285	cell = candidate;
267	286	candidate = NULL;
	287	+ atomic_set(&cell->active, 2);
	288	+ trace_afs_cell(cell->debug_id, atomic_read(&cell->ref), 2, afs_cell_trace_insert);
268	289	rb_link_node_rcu(&cell->net_node, parent, pp);
269	290	rb_insert_color(&cell->net_node, &net->cells);
270		- atomic_inc(&net->cells_outstanding);
271		- write_sequnlock(&net->cells_lock);
	291	+ up_write(&net->cells_lock);
272	292
273		- queue_work(afs_wq, &cell->manager);
	293	+ afs_queue_cell(cell, afs_cell_trace_get_queue_new);
274	294
275	295	wait_for_cell:
	296	+ trace_afs_cell(cell->debug_id, atomic_read(&cell->ref), atomic_read(&cell->active),
	297	+ afs_cell_trace_wait);
276	298	_debug("wait_for_cell");
277		- ret = wait_on_bit(&cell->flags, AFS_CELL_FL_NOT_READY, TASK_INTERRUPTIBLE);
278		- smp_rmb();
	299	+ wait_var_event(&cell->state,
	300	+ ({
	301	+ state = smp_load_acquire(&cell->state); /* vs error */
	302	+ state == AFS_CELL_ACTIVE \|\| state == AFS_CELL_REMOVED;
	303	+ }));
279	304
280		- switch (READ_ONCE(cell->state)) {
281		- case AFS_CELL_FAILED:
	305	+ /* Check the state obtained from the wait check. */
	306	+ if (state == AFS_CELL_REMOVED) {
282	307	ret = cell->error;
283	308	goto error;
284		- default:
285		- _debug("weird %u %d", cell->state, cell->error);
286		- goto error;
287		- case AFS_CELL_ACTIVE:
288		- break;
289	309	}
290	310
291	311	_leave(" = %p [cell]", cell);
..	..	@@ -297,16 +317,17 @@
297	317	if (excl) {
298	318	ret = -EEXIST;
299	319	} else {
300		- afs_get_cell(cursor);
	320	+ afs_use_cell(cursor, afs_cell_trace_use_lookup);
301	321	ret = 0;
302	322	}
303		- write_sequnlock(&net->cells_lock);
304		- kfree(candidate);
	323	+ up_write(&net->cells_lock);
	324	+ if (candidate)
	325	+ afs_put_cell(candidate, afs_cell_trace_put_candidate);
305	326	if (ret == 0)
306	327	goto wait_for_cell;
307	328	goto error_noput;
308	329	error:
309		- afs_put_cell(net, cell);
	330	+ afs_unuse_cell(net, cell, afs_cell_trace_unuse_lookup);
310	331	error_noput:
311	332	_leave(" = %d [error]", ret);
312	333	return ERR_PTR(ret);
..	..	@@ -351,15 +372,16 @@
351	372	}
352	373
353	374	if (!test_and_set_bit(AFS_CELL_FL_NO_GC, &new_root->flags))
354		- afs_get_cell(new_root);
	375	+ afs_use_cell(new_root, afs_cell_trace_use_pin);
355	376
356	377	/* install the new cell */
357		- write_seqlock(&net->cells_lock);
358		- old_root = rcu_access_pointer(net->ws_cell);
359		- rcu_assign_pointer(net->ws_cell, new_root);
360		- write_sequnlock(&net->cells_lock);
	378	+ down_write(&net->cells_lock);
	379	+ afs_see_cell(new_root, afs_cell_trace_see_ws);
	380	+ old_root = net->ws_cell;
	381	+ net->ws_cell = new_root;
	382	+ up_write(&net->cells_lock);
361	383
362		- afs_put_cell(net, old_root);
	384	+ afs_unuse_cell(net, old_root, afs_cell_trace_unuse_ws);
363	385	_leave(" = 0");
364	386	return 0;
365	387	}
..	..	@@ -367,53 +389,96 @@
367	389	/*
368	390	* Update a cell's VL server address list from the DNS.
369	391	*/
370		-static void afs_update_cell(struct afs_cell *cell)
	392	+static int afs_update_cell(struct afs_cell *cell)
371	393	{
372		- struct afs_addr_list alist, old;
373		- time64_t now, expiry;
	394	+ struct afs_vlserver_list vllist, old = NULL, *p;
	395	+ unsigned int min_ttl = READ_ONCE(afs_cell_min_ttl);
	396	+ unsigned int max_ttl = READ_ONCE(afs_cell_max_ttl);
	397	+ time64_t now, expiry = 0;
	398	+ int ret = 0;
374	399
375	400	_enter("%s", cell->name);
376	401
377		- alist = afs_dns_query(cell, &expiry);
378		- if (IS_ERR(alist)) {
379		- switch (PTR_ERR(alist)) {
380		- case -ENODATA:
381		- /* The DNS said that the cell does not exist */
382		- set_bit(AFS_CELL_FL_NOT_FOUND, &cell->flags);
383		- clear_bit(AFS_CELL_FL_DNS_FAIL, &cell->flags);
384		- cell->dns_expiry = ktime_get_real_seconds() + 61;
385		- break;
	402	+ vllist = afs_dns_query(cell, &expiry);
	403	+ if (IS_ERR(vllist)) {
	404	+ ret = PTR_ERR(vllist);
386	405
	406	+ _debug("%s: fail %d", cell->name, ret);
	407	+ if (ret == -ENOMEM)
	408	+ goto out_wake;
	409	+
	410	+ ret = -ENOMEM;
	411	+ vllist = afs_alloc_vlserver_list(0);
	412	+ if (!vllist)
	413	+ goto out_wake;
	414	+
	415	+ switch (ret) {
	416	+ case -ENODATA:
	417	+ case -EDESTADDRREQ:
	418	+ vllist->status = DNS_LOOKUP_GOT_NOT_FOUND;
	419	+ break;
387	420	case -EAGAIN:
388	421	case -ECONNREFUSED:
	422	+ vllist->status = DNS_LOOKUP_GOT_TEMP_FAILURE;
	423	+ break;
389	424	default:
390		- set_bit(AFS_CELL_FL_DNS_FAIL, &cell->flags);
391		- cell->dns_expiry = ktime_get_real_seconds() + 10;
	425	+ vllist->status = DNS_LOOKUP_GOT_LOCAL_FAILURE;
392	426	break;
393	427	}
394		-
395		- cell->error = -EDESTADDRREQ;
396		- } else {
397		- clear_bit(AFS_CELL_FL_DNS_FAIL, &cell->flags);
398		- clear_bit(AFS_CELL_FL_NOT_FOUND, &cell->flags);
399		-
400		- /* Exclusion on changing vl_addrs is achieved by a
401		- * non-reentrant work item.
402		- */
403		- old = rcu_dereference_protected(cell->vl_addrs, true);
404		- rcu_assign_pointer(cell->vl_addrs, alist);
405		- cell->dns_expiry = expiry;
406		-
407		- if (old)
408		- afs_put_addrlist(old);
409	428	}
410	429
411		- if (test_and_clear_bit(AFS_CELL_FL_NO_LOOKUP_YET, &cell->flags))
412		- wake_up_bit(&cell->flags, AFS_CELL_FL_NO_LOOKUP_YET);
	430	+ _debug("%s: got list %d %d", cell->name, vllist->source, vllist->status);
	431	+ cell->dns_status = vllist->status;
413	432
414	433	now = ktime_get_real_seconds();
415		- afs_set_cell_timer(cell->net, cell->dns_expiry - now);
416		- _leave("");
	434	+ if (min_ttl > max_ttl)
	435	+ max_ttl = min_ttl;
	436	+ if (expiry < now + min_ttl)
	437	+ expiry = now + min_ttl;
	438	+ else if (expiry > now + max_ttl)
	439	+ expiry = now + max_ttl;
	440	+
	441	+ _debug("%s: status %d", cell->name, vllist->status);
	442	+ if (vllist->source == DNS_RECORD_UNAVAILABLE) {
	443	+ switch (vllist->status) {
	444	+ case DNS_LOOKUP_GOT_NOT_FOUND:
	445	+ /* The DNS said that the cell does not exist or there
	446	+ * weren't any addresses to be had.
	447	+ */
	448	+ cell->dns_expiry = expiry;
	449	+ break;
	450	+
	451	+ case DNS_LOOKUP_BAD:
	452	+ case DNS_LOOKUP_GOT_LOCAL_FAILURE:
	453	+ case DNS_LOOKUP_GOT_TEMP_FAILURE:
	454	+ case DNS_LOOKUP_GOT_NS_FAILURE:
	455	+ default:
	456	+ cell->dns_expiry = now + 10;
	457	+ break;
	458	+ }
	459	+ } else {
	460	+ cell->dns_expiry = expiry;
	461	+ }
	462	+
	463	+ /* Replace the VL server list if the new record has servers or the old
	464	+ * record doesn't.
	465	+ */
	466	+ write_lock(&cell->vl_servers_lock);
	467	+ p = rcu_dereference_protected(cell->vl_servers, true);
	468	+ if (vllist->nr_servers > 0 \|\| p->nr_servers == 0) {
	469	+ rcu_assign_pointer(cell->vl_servers, vllist);
	470	+ cell->dns_source = vllist->source;
	471	+ old = p;
	472	+ }
	473	+ write_unlock(&cell->vl_servers_lock);
	474	+ afs_put_vlserverlist(cell->net, old);
	475	+
	476	+out_wake:
	477	+ smp_store_release(&cell->dns_lookup_count,
	478	+ cell->dns_lookup_count + 1); /* vs source/status */
	479	+ wake_up_var(&cell->dns_lookup_count);
	480	+ _leave(" = %d", ret);
	481	+ return ret;
417	482	}
418	483
419	484	/*
..	..	@@ -422,15 +487,22 @@
422	487	static void afs_cell_destroy(struct rcu_head *rcu)
423	488	{
424	489	struct afs_cell *cell = container_of(rcu, struct afs_cell, rcu);
	490	+ struct afs_net *net = cell->net;
	491	+ int u;
425	492
426	493	_enter("%p{%s}", cell, cell->name);
427	494
428		- ASSERTCMP(atomic_read(&cell->usage), ==, 0);
	495	+ u = atomic_read(&cell->ref);
	496	+ ASSERTCMP(u, ==, 0);
	497	+ trace_afs_cell(cell->debug_id, u, atomic_read(&cell->active), afs_cell_trace_free);
429	498
430		- afs_put_addrlist(rcu_access_pointer(cell->vl_addrs));
	499	+ afs_put_vlserverlist(net, rcu_access_pointer(cell->vl_servers));
	500	+ afs_unuse_cell(net, cell->alias_of, afs_cell_trace_unuse_alias);
431	501	key_put(cell->anonymous_key);
	502	+ kfree(cell->name);
432	503	kfree(cell);
433	504
	505	+ afs_dec_cells_outstanding(net);
434	506	_leave(" [destroyed]");
435	507	}
436	508
..	..	@@ -463,18 +535,63 @@
463	535	/*
464	536	* Get a reference on a cell record.
465	537	*/
466		-struct afs_cell afs_get_cell(struct afs_cell cell)
	538	+struct afs_cell afs_get_cell(struct afs_cell cell, enum afs_cell_trace reason)
467	539	{
468		- atomic_inc(&cell->usage);
	540	+ int u;
	541	+
	542	+ if (atomic_read(&cell->ref) <= 0)
	543	+ BUG();
	544	+
	545	+ u = atomic_inc_return(&cell->ref);
	546	+ trace_afs_cell(cell->debug_id, u, atomic_read(&cell->active), reason);
469	547	return cell;
470	548	}
471	549
472	550	/*
473	551	* Drop a reference on a cell record.
474	552	*/
475		-void afs_put_cell(struct afs_net net, struct afs_cell cell)
	553	+void afs_put_cell(struct afs_cell *cell, enum afs_cell_trace reason)
476	554	{
	555	+ if (cell) {
	556	+ unsigned int debug_id = cell->debug_id;
	557	+ unsigned int u, a;
	558	+
	559	+ a = atomic_read(&cell->active);
	560	+ u = atomic_dec_return(&cell->ref);
	561	+ trace_afs_cell(debug_id, u, a, reason);
	562	+ if (u == 0) {
	563	+ a = atomic_read(&cell->active);
	564	+ WARN(a != 0, "Cell active count %u > 0\n", a);
	565	+ call_rcu(&cell->rcu, afs_cell_destroy);
	566	+ }
	567	+ }
	568	+}
	569	+
	570	+/*
	571	+ * Note a cell becoming more active.
	572	+ */
	573	+struct afs_cell afs_use_cell(struct afs_cell cell, enum afs_cell_trace reason)
	574	+{
	575	+ int u, a;
	576	+
	577	+ if (atomic_read(&cell->ref) <= 0)
	578	+ BUG();
	579	+
	580	+ u = atomic_read(&cell->ref);
	581	+ a = atomic_inc_return(&cell->active);
	582	+ trace_afs_cell(cell->debug_id, u, a, reason);
	583	+ return cell;
	584	+}
	585	+
	586	+/*
	587	+ * Record a cell becoming less active. When the active counter reaches 1, it
	588	+ * is scheduled for destruction, but may get reactivated.
	589	+ */
	590	+void afs_unuse_cell(struct afs_net net, struct afs_cell cell, enum afs_cell_trace reason)
	591	+{
	592	+ unsigned int debug_id;
477	593	time64_t now, expire_delay;
	594	+ int u, a;
478	595
479	596	if (!cell)
480	597	return;
..	..	@@ -484,15 +601,39 @@
484	601	now = ktime_get_real_seconds();
485	602	cell->last_inactive = now;
486	603	expire_delay = 0;
487		- if (!test_bit(AFS_CELL_FL_DNS_FAIL, &cell->flags) &&
488		- !test_bit(AFS_CELL_FL_NOT_FOUND, &cell->flags))
	604	+ if (cell->vl_servers->nr_servers)
489	605	expire_delay = afs_cell_gc_delay;
490	606
491		- if (atomic_dec_return(&cell->usage) > 1)
492		- return;
	607	+ debug_id = cell->debug_id;
	608	+ u = atomic_read(&cell->ref);
	609	+ a = atomic_dec_return(&cell->active);
	610	+ trace_afs_cell(debug_id, u, a, reason);
	611	+ WARN_ON(a == 0);
	612	+ if (a == 1)
	613	+ /* 'cell' may now be garbage collected. */
	614	+ afs_set_cell_timer(net, expire_delay);
	615	+}
493	616
494		- /* 'cell' may now be garbage collected. */
495		- afs_set_cell_timer(net, expire_delay);
	617	+/*
	618	+ * Note that a cell has been seen.
	619	+ */
	620	+void afs_see_cell(struct afs_cell *cell, enum afs_cell_trace reason)
	621	+{
	622	+ int u, a;
	623	+
	624	+ u = atomic_read(&cell->ref);
	625	+ a = atomic_read(&cell->active);
	626	+ trace_afs_cell(cell->debug_id, u, a, reason);
	627	+}
	628	+
	629	+/*
	630	+ * Queue a cell for management, giving the workqueue a ref to hold.
	631	+ */
	632	+void afs_queue_cell(struct afs_cell *cell, enum afs_cell_trace reason)
	633	+{
	634	+ afs_get_cell(cell, reason);
	635	+ if (!queue_work(afs_wq, &cell->manager))
	636	+ afs_put_cell(cell, afs_cell_trace_put_queue_fail);
496	637	}
497	638
498	639	/*
..	..	@@ -592,12 +733,10 @@
592	733	* Manage a cell record, initialising and destroying it, maintaining its DNS
593	734	* records.
594	735	*/
595		-static void afs_manage_cell(struct work_struct *work)
	736	+static void afs_manage_cell(struct afs_cell *cell)
596	737	{
597		- struct afs_cell *cell = container_of(work, struct afs_cell, manager);
598	738	struct afs_net *net = cell->net;
599		- bool deleted;
600		- int ret, usage;
	739	+ int ret, active;
601	740
602	741	_enter("%s", cell->name);
603	742
..	..	@@ -606,21 +745,28 @@
606	745	switch (cell->state) {
607	746	case AFS_CELL_INACTIVE:
608	747	case AFS_CELL_FAILED:
609		- write_seqlock(&net->cells_lock);
610		- usage = 1;
611		- deleted = atomic_try_cmpxchg_relaxed(&cell->usage, &usage, 0);
612		- if (deleted)
	748	+ down_write(&net->cells_lock);
	749	+ active = 1;
	750	+ if (atomic_try_cmpxchg_relaxed(&cell->active, &active, 0)) {
613	751	rb_erase(&cell->net_node, &net->cells);
614		- write_sequnlock(&net->cells_lock);
615		- if (deleted)
	752	+ trace_afs_cell(cell->debug_id, atomic_read(&cell->ref), 0,
	753	+ afs_cell_trace_unuse_delete);
	754	+ smp_store_release(&cell->state, AFS_CELL_REMOVED);
	755	+ }
	756	+ up_write(&net->cells_lock);
	757	+ if (cell->state == AFS_CELL_REMOVED) {
	758	+ wake_up_var(&cell->state);
616	759	goto final_destruction;
	760	+ }
617	761	if (cell->state == AFS_CELL_FAILED)
618	762	goto done;
619		- cell->state = AFS_CELL_UNSET;
	763	+ smp_store_release(&cell->state, AFS_CELL_UNSET);
	764	+ wake_up_var(&cell->state);
620	765	goto again;
621	766
622	767	case AFS_CELL_UNSET:
623		- cell->state = AFS_CELL_ACTIVATING;
	768	+ smp_store_release(&cell->state, AFS_CELL_ACTIVATING);
	769	+ wake_up_var(&cell->state);
624	770	goto again;
625	771
626	772	case AFS_CELL_ACTIVATING:
..	..	@@ -628,29 +774,33 @@
628	774	if (ret < 0)
629	775	goto activation_failed;
630	776
631		- cell->state = AFS_CELL_ACTIVE;
632		- smp_wmb();
633		- clear_bit(AFS_CELL_FL_NOT_READY, &cell->flags);
634		- wake_up_bit(&cell->flags, AFS_CELL_FL_NOT_READY);
	777	+ smp_store_release(&cell->state, AFS_CELL_ACTIVE);
	778	+ wake_up_var(&cell->state);
635	779	goto again;
636	780
637	781	case AFS_CELL_ACTIVE:
638		- if (atomic_read(&cell->usage) > 1) {
639		- time64_t now = ktime_get_real_seconds();
640		- if (cell->dns_expiry <= now && net->live)
641		- afs_update_cell(cell);
	782	+ if (atomic_read(&cell->active) > 1) {
	783	+ if (test_and_clear_bit(AFS_CELL_FL_DO_LOOKUP, &cell->flags)) {
	784	+ ret = afs_update_cell(cell);
	785	+ if (ret < 0)
	786	+ cell->error = ret;
	787	+ }
642	788	goto done;
643	789	}
644		- cell->state = AFS_CELL_DEACTIVATING;
	790	+ smp_store_release(&cell->state, AFS_CELL_DEACTIVATING);
	791	+ wake_up_var(&cell->state);
645	792	goto again;
646	793
647	794	case AFS_CELL_DEACTIVATING:
648		- set_bit(AFS_CELL_FL_NOT_READY, &cell->flags);
649		- if (atomic_read(&cell->usage) > 1)
	795	+ if (atomic_read(&cell->active) > 1)
650	796	goto reverse_deactivation;
651	797	afs_deactivate_cell(net, cell);
652		- cell->state = AFS_CELL_INACTIVE;
	798	+ smp_store_release(&cell->state, AFS_CELL_INACTIVE);
	799	+ wake_up_var(&cell->state);
653	800	goto again;
	801	+
	802	+ case AFS_CELL_REMOVED:
	803	+ goto done;
654	804
655	805	default:
656	806	break;
..	..	@@ -662,17 +812,13 @@
662	812	cell->error = ret;
663	813	afs_deactivate_cell(net, cell);
664	814
665		- cell->state = AFS_CELL_FAILED;
666		- smp_wmb();
667		- if (test_and_clear_bit(AFS_CELL_FL_NOT_READY, &cell->flags))
668		- wake_up_bit(&cell->flags, AFS_CELL_FL_NOT_READY);
	815	+ smp_store_release(&cell->state, AFS_CELL_FAILED); /* vs error */
	816	+ wake_up_var(&cell->state);
669	817	goto again;
670	818
671	819	reverse_deactivation:
672		- cell->state = AFS_CELL_ACTIVE;
673		- smp_wmb();
674		- clear_bit(AFS_CELL_FL_NOT_READY, &cell->flags);
675		- wake_up_bit(&cell->flags, AFS_CELL_FL_NOT_READY);
	820	+ smp_store_release(&cell->state, AFS_CELL_ACTIVE);
	821	+ wake_up_var(&cell->state);
676	822	_leave(" [deact->act]");
677	823	return;
678	824
..	..	@@ -681,9 +827,18 @@
681	827	return;
682	828
683	829	final_destruction:
684		- call_rcu(&cell->rcu, afs_cell_destroy);
685		- afs_dec_cells_outstanding(net);
686		- _leave(" [destruct %d]", atomic_read(&net->cells_outstanding));
	830	+ /* The root volume is pinning the cell */
	831	+ afs_put_volume(cell->net, cell->root_volume, afs_volume_trace_put_cell_root);
	832	+ cell->root_volume = NULL;
	833	+ afs_put_cell(cell, afs_cell_trace_put_destroy);
	834	+}
	835	+
	836	+static void afs_manage_cell_work(struct work_struct *work)
	837	+{
	838	+ struct afs_cell *cell = container_of(work, struct afs_cell, manager);
	839	+
	840	+ afs_manage_cell(cell);
	841	+ afs_put_cell(cell, afs_cell_trace_put_queue_work);
687	842	}
688	843
689	844	/*
..	..	@@ -712,31 +867,39 @@
712	867	* lack of use and cells whose DNS results have expired and dispatch
713	868	* their managers.
714	869	*/
715		- read_seqlock_excl(&net->cells_lock);
	870	+ down_read(&net->cells_lock);
716	871
717	872	for (cursor = rb_first(&net->cells); cursor; cursor = rb_next(cursor)) {
718	873	struct afs_cell *cell =
719	874	rb_entry(cursor, struct afs_cell, net_node);
720		- unsigned usage;
	875	+ unsigned active;
721	876	bool sched_cell = false;
722	877
723		- usage = atomic_read(&cell->usage);
724		- _debug("manage %s %u", cell->name, usage);
	878	+ active = atomic_read(&cell->active);
	879	+ trace_afs_cell(cell->debug_id, atomic_read(&cell->ref),
	880	+ active, afs_cell_trace_manage);
725	881
726		- ASSERTCMP(usage, >=, 1);
	882	+ ASSERTCMP(active, >=, 1);
727	883
728	884	if (purging) {
729		- if (test_and_clear_bit(AFS_CELL_FL_NO_GC, &cell->flags))
730		- usage = atomic_dec_return(&cell->usage);
731		- ASSERTCMP(usage, ==, 1);
	885	+ if (test_and_clear_bit(AFS_CELL_FL_NO_GC, &cell->flags)) {
	886	+ active = atomic_dec_return(&cell->active);
	887	+ trace_afs_cell(cell->debug_id, atomic_read(&cell->ref),
	888	+ active, afs_cell_trace_unuse_pin);
	889	+ }
732	890	}
733	891
734		- if (usage == 1) {
	892	+ if (active == 1) {
	893	+ struct afs_vlserver_list *vllist;
735	894	time64_t expire_at = cell->last_inactive;
736	895
737		- if (!test_bit(AFS_CELL_FL_DNS_FAIL, &cell->flags) &&
738		- !test_bit(AFS_CELL_FL_NOT_FOUND, &cell->flags))
	896	+ read_lock(&cell->vl_servers_lock);
	897	+ vllist = rcu_dereference_protected(
	898	+ cell->vl_servers,
	899	+ lockdep_is_held(&cell->vl_servers_lock));
	900	+ if (vllist->nr_servers > 0)
739	901	expire_at += afs_cell_gc_delay;
	902	+ read_unlock(&cell->vl_servers_lock);
740	903	if (purging \|\| expire_at <= now)
741	904	sched_cell = true;
742	905	else if (expire_at < next_manage)
..	..	@@ -744,17 +907,15 @@
744	907	}
745	908
746	909	if (!purging) {
747		- if (cell->dns_expiry <= now)
	910	+ if (test_bit(AFS_CELL_FL_DO_LOOKUP, &cell->flags))
748	911	sched_cell = true;
749		- else if (cell->dns_expiry <= next_manage)
750		- next_manage = cell->dns_expiry;
751	912	}
752	913
753	914	if (sched_cell)
754		- queue_work(afs_wq, &cell->manager);
	915	+ afs_queue_cell(cell, afs_cell_trace_get_queue_manage);
755	916	}
756	917
757		- read_sequnlock_excl(&net->cells_lock);
	918	+ up_read(&net->cells_lock);
758	919
759	920	/* Update the timer on the way out. We have to pass an increment on
760	921	* cells_outstanding in the namespace that we are in to the timer or
..	..	@@ -784,11 +945,11 @@
784	945
785	946	_enter("");
786	947
787		- write_seqlock(&net->cells_lock);
788		- ws = rcu_access_pointer(net->ws_cell);
789		- RCU_INIT_POINTER(net->ws_cell, NULL);
790		- write_sequnlock(&net->cells_lock);
791		- afs_put_cell(net, ws);
	948	+ down_write(&net->cells_lock);
	949	+ ws = net->ws_cell;
	950	+ net->ws_cell = NULL;
	951	+ up_write(&net->cells_lock);
	952	+ afs_unuse_cell(net, ws, afs_cell_trace_unuse_ws);
792	953
793	954	_debug("del timer");
794	955	if (del_timer_sync(&net->cells_timer))