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2024-01-05 071106ecf68c401173c58808b1cf5f68cc50d390 
 kernel/fs/afs/rotate.c
....@@ -1,12 +1,8 @@
1
+// SPDX-License-Identifier: GPL-2.0-or-later
12 /* Handle fileserver selection and rotation.
23  *
34  * Copyright (C) 2017 Red Hat, Inc. All Rights Reserved.
45  * 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 Licence
8
- * as published by the Free Software Foundation; either version
9
- * 2 of the Licence, or (at your option) any later version.
106  */
117 
128 #include <linux/kernel.h>
....@@ -19,58 +15,32 @@
1915 #include "afs_fs.h"
2016 
2117 /*
22
- * Initialise a filesystem server cursor for iterating over FS servers.
23
- */
24
-static void afs_init_fs_cursor(struct afs_fs_cursor *fc, struct afs_vnode *vnode)
25
-{
26
-	memset(fc, 0, sizeof(*fc));
27
-}
28
-
29
-/*
30
- * Begin an operation on the fileserver.
31
- *
32
- * Fileserver operations are serialised on the server by vnode, so we serialise
33
- * them here also using the io_lock.
34
- */
35
-bool afs_begin_vnode_operation(struct afs_fs_cursor *fc, struct afs_vnode *vnode,
36
-			       struct key *key)
37
-{
38
-	afs_init_fs_cursor(fc, vnode);
39
-	fc->vnode = vnode;
40
-	fc->key = key;
41
-	fc->ac.error = SHRT_MAX;
42
-
43
-	if (mutex_lock_interruptible(&vnode->io_lock) < 0) {
44
-		fc->ac.error = -EINTR;
45
-		fc->flags |= AFS_FS_CURSOR_STOP;
46
-		return false;
47
-	}
48
-
49
-	if (vnode->lock_state != AFS_VNODE_LOCK_NONE)
50
-		fc->flags |= AFS_FS_CURSOR_CUR_ONLY;
51
-	return true;
52
-}
53
-
54
-/*
5518  * Begin iteration through a server list, starting with the vnode's last used
5619  * server if possible, or the last recorded good server if not.
5720  */
58
-static bool afs_start_fs_iteration(struct afs_fs_cursor *fc,
21
+static bool afs_start_fs_iteration(struct afs_operation *op,
5922 				   struct afs_vnode *vnode)
6023 {
61
-	struct afs_cb_interest *cbi;
24
+	struct afs_server *server;
25
+	void *cb_server;
6226 	int i;
6327 
64
-	read_lock(&vnode->volume->servers_lock);
65
-	fc->server_list = afs_get_serverlist(vnode->volume->servers);
66
-	read_unlock(&vnode->volume->servers_lock);
28
+	read_lock(&op->volume->servers_lock);
29
+	op->server_list = afs_get_serverlist(
30
+		rcu_dereference_protected(op->volume->servers,
31
+					  lockdep_is_held(&op->volume->servers_lock)));
32
+	read_unlock(&op->volume->servers_lock);
6733 
68
-	cbi = vnode->cb_interest;
69
-	if (cbi) {
34
+	op->untried = (1UL << op->server_list->nr_servers) - 1;
35
+	op->index = READ_ONCE(op->server_list->preferred);
36
+
37
+	cb_server = vnode->cb_server;
38
+	if (cb_server) {
7039 		/* See if the vnode's preferred record is still available */
71
-		for (i = 0; i < fc->server_list->nr_servers; i++) {
72
-			if (fc->server_list->servers[i].cb_interest == cbi) {
73
-				fc->start = i;
40
+		for (i = 0; i < op->server_list->nr_servers; i++) {
41
+			server = op->server_list->servers[i].server;
42
+			if (server == cb_server) {
43
+				op->index = i;
7444 				goto found_interest;
7545 			}
7646 		}
....@@ -79,27 +49,21 @@
7949 		 * serving this vnode, then we can't switch to another server
8050 		 * and have to return an error.
8151 		 */
82
-		if (fc->flags & AFS_FS_CURSOR_CUR_ONLY) {
83
-			fc->ac.error = -ESTALE;
52
+		if (op->flags & AFS_OPERATION_CUR_ONLY) {
53
+			op->error = -ESTALE;
8454 			return false;
8555 		}
8656 
8757 		/* Note that the callback promise is effectively broken */
8858 		write_seqlock(&vnode->cb_lock);
89
-		ASSERTCMP(cbi, ==, vnode->cb_interest);
90
-		vnode->cb_interest = NULL;
59
+		ASSERTCMP(cb_server, ==, vnode->cb_server);
60
+		vnode->cb_server = NULL;
9161 		if (test_and_clear_bit(AFS_VNODE_CB_PROMISED, &vnode->flags))
9262 			vnode->cb_break++;
9363 		write_sequnlock(&vnode->cb_lock);
94
-
95
-		afs_put_cb_interest(afs_v2net(vnode), cbi);
96
-		cbi = NULL;
97
-	} else {
98
-		fc->start = READ_ONCE(fc->server_list->index);
9964 	}
10065 
10166 found_interest:
102
-	fc->index = fc->start;
10367 	return true;
10468 }
10569 
....@@ -117,18 +81,22 @@
11781 	default:		m = "busy";		break;
11882 	}
11983 
120
-	pr_notice("kAFS: Volume %u '%s' is %s\n", volume->vid, volume->name, m);
84
+	pr_notice("kAFS: Volume %llu '%s' is %s\n", volume->vid, volume->name, m);
12185 }
12286 
12387 /*
12488  * Sleep and retry the operation to the same fileserver.
12589  */
126
-static bool afs_sleep_and_retry(struct afs_fs_cursor *fc)
90
+static bool afs_sleep_and_retry(struct afs_operation *op)
12791 {
128
-	msleep_interruptible(1000);
129
-	if (signal_pending(current)) {
130
-		fc->ac.error = -ERESTARTSYS;
131
-		return false;
92
+	if (!(op->flags & AFS_OPERATION_UNINTR)) {
93
+		msleep_interruptible(1000);
94
+		if (signal_pending(current)) {
95
+			op->error = -ERESTARTSYS;
96
+			return false;
97
+		}
98
+	} else {
99
+		msleep(1000);
132100 	}
133101 
134102 	return true;
....@@ -138,74 +106,80 @@
138106  * Select the fileserver to use.  May be called multiple times to rotate
139107  * through the fileservers.
140108  */
141
-bool afs_select_fileserver(struct afs_fs_cursor *fc)
109
+bool afs_select_fileserver(struct afs_operation *op)
142110 {
143111 	struct afs_addr_list *alist;
144112 	struct afs_server *server;
145
-	struct afs_vnode *vnode = fc->vnode;
113
+	struct afs_vnode *vnode = op->file[0].vnode;
114
+	struct afs_error e;
115
+	u32 rtt;
116
+	int error = op->ac.error, i;
146117 
147
-	_enter("%u/%u,%u/%u,%d,%d",
148
-	       fc->index, fc->start,
149
-	       fc->ac.index, fc->ac.start,
150
-	       fc->ac.error, fc->ac.abort_code);
118
+	_enter("%lx[%d],%lx[%d],%d,%d",
119
+	       op->untried, op->index,
120
+	       op->ac.tried, op->ac.index,
121
+	       error, op->ac.abort_code);
151122 
152
-	if (fc->flags & AFS_FS_CURSOR_STOP) {
123
+	if (op->flags & AFS_OPERATION_STOP) {
153124 		_leave(" = f [stopped]");
154125 		return false;
155126 	}
156127 
128
+	op->nr_iterations++;
129
+
157130 	/* Evaluate the result of the previous operation, if there was one. */
158
-	switch (fc->ac.error) {
131
+	switch (error) {
159132 	case SHRT_MAX:
160133 		goto start;
161134 
162135 	case 0:
163136 	default:
164137 		/* Success or local failure.  Stop. */
165
-		fc->flags |= AFS_FS_CURSOR_STOP;
166
-		_leave(" = f [okay/local %d]", fc->ac.error);
138
+		op->error = error;
139
+		op->flags |= AFS_OPERATION_STOP;
140
+		_leave(" = f [okay/local %d]", error);
167141 		return false;
168142 
169143 	case -ECONNABORTED:
170144 		/* The far side rejected the operation on some grounds.  This
171145 		 * might involve the server being busy or the volume having been moved.
172146 		 */
173
-		switch (fc->ac.abort_code) {
147
+		switch (op->ac.abort_code) {
174148 		case VNOVOL:
175149 			/* This fileserver doesn't know about the volume.
176150 			 * - May indicate that the VL is wrong - retry once and compare
177151 			 *   the results.
178152 			 * - May indicate that the fileserver couldn't attach to the vol.
179153 			 */
180
-			if (fc->flags & AFS_FS_CURSOR_VNOVOL) {
181
-				fc->ac.error = -EREMOTEIO;
154
+			if (op->flags & AFS_OPERATION_VNOVOL) {
155
+				op->error = -EREMOTEIO;
182156 				goto next_server;
183157 			}
184158 
185
-			write_lock(&vnode->volume->servers_lock);
186
-			fc->server_list->vnovol_mask |= 1 << fc->index;
187
-			write_unlock(&vnode->volume->servers_lock);
159
+			write_lock(&op->volume->servers_lock);
160
+			op->server_list->vnovol_mask |= 1 << op->index;
161
+			write_unlock(&op->volume->servers_lock);
188162 
189
-			set_bit(AFS_VOLUME_NEEDS_UPDATE, &vnode->volume->flags);
190
-			fc->ac.error = afs_check_volume_status(vnode->volume, fc->key);
191
-			if (fc->ac.error < 0)
192
-				goto failed;
163
+			set_bit(AFS_VOLUME_NEEDS_UPDATE, &op->volume->flags);
164
+			error = afs_check_volume_status(op->volume, op);
165
+			if (error < 0)
166
+				goto failed_set_error;
193167 
194
-			if (test_bit(AFS_VOLUME_DELETED, &vnode->volume->flags)) {
195
-				fc->ac.error = -ENOMEDIUM;
168
+			if (test_bit(AFS_VOLUME_DELETED, &op->volume->flags)) {
169
+				op->error = -ENOMEDIUM;
196170 				goto failed;
197171 			}
198172 
199173 			/* If the server list didn't change, then assume that
200174 			 * it's the fileserver having trouble.
201175 			 */
202
-			if (vnode->volume->servers == fc->server_list) {
203
-				fc->ac.error = -EREMOTEIO;
176
+			if (rcu_access_pointer(op->volume->servers) == op->server_list) {
177
+				op->error = -EREMOTEIO;
204178 				goto next_server;
205179 			}
206180 
207181 			/* Try again */
208
-			fc->flags |= AFS_FS_CURSOR_VNOVOL;
182
+			op->flags |= AFS_OPERATION_VNOVOL;
209183 			_leave(" = t [vnovol]");
210184 			return true;
211185 
....@@ -215,20 +189,20 @@
215189 		case VONLINE:
216190 		case VDISKFULL:
217191 		case VOVERQUOTA:
218
-			fc->ac.error = afs_abort_to_error(fc->ac.abort_code);
192
+			op->error = afs_abort_to_error(op->ac.abort_code);
219193 			goto next_server;
220194 
221195 		case VOFFLINE:
222
-			if (!test_and_set_bit(AFS_VOLUME_OFFLINE, &vnode->volume->flags)) {
223
-				afs_busy(vnode->volume, fc->ac.abort_code);
224
-				clear_bit(AFS_VOLUME_BUSY, &vnode->volume->flags);
196
+			if (!test_and_set_bit(AFS_VOLUME_OFFLINE, &op->volume->flags)) {
197
+				afs_busy(op->volume, op->ac.abort_code);
198
+				clear_bit(AFS_VOLUME_BUSY, &op->volume->flags);
225199 			}
226
-			if (fc->flags & AFS_FS_CURSOR_NO_VSLEEP) {
227
-				fc->ac.error = -EADV;
200
+			if (op->flags & AFS_OPERATION_NO_VSLEEP) {
201
+				op->error = -EADV;
228202 				goto failed;
229203 			}
230
-			if (fc->flags & AFS_FS_CURSOR_CUR_ONLY) {
231
-				fc->ac.error = -ESTALE;
204
+			if (op->flags & AFS_OPERATION_CUR_ONLY) {
205
+				op->error = -ESTALE;
232206 				goto failed;
233207 			}
234208 			goto busy;
....@@ -239,17 +213,17 @@
239213 			/* Retry after going round all the servers unless we
240214 			 * have a file lock we need to maintain.
241215 			 */
242
-			if (fc->flags & AFS_FS_CURSOR_NO_VSLEEP) {
243
-				fc->ac.error = -EBUSY;
216
+			if (op->flags & AFS_OPERATION_NO_VSLEEP) {
217
+				op->error = -EBUSY;
244218 				goto failed;
245219 			}
246
-			if (!test_and_set_bit(AFS_VOLUME_BUSY, &vnode->volume->flags)) {
247
-				afs_busy(vnode->volume, fc->ac.abort_code);
248
-				clear_bit(AFS_VOLUME_OFFLINE, &vnode->volume->flags);
220
+			if (!test_and_set_bit(AFS_VOLUME_BUSY, &op->volume->flags)) {
221
+				afs_busy(op->volume, op->ac.abort_code);
222
+				clear_bit(AFS_VOLUME_OFFLINE, &op->volume->flags);
249223 			}
250224 		busy:
251
-			if (fc->flags & AFS_FS_CURSOR_CUR_ONLY) {
252
-				if (!afs_sleep_and_retry(fc))
225
+			if (op->flags & AFS_OPERATION_CUR_ONLY) {
226
+				if (!afs_sleep_and_retry(op))
253227 					goto failed;
254228 
255229 				 /* Retry with same server & address */
....@@ -257,7 +231,7 @@
257231 				return true;
258232 			}
259233 
260
-			fc->flags |= AFS_FS_CURSOR_VBUSY;
234
+			op->flags |= AFS_OPERATION_VBUSY;
261235 			goto next_server;
262236 
263237 		case VMOVED:
....@@ -268,17 +242,17 @@
268242 			 * We also limit the number of VMOVED hops we will
269243 			 * honour, just in case someone sets up a loop.
270244 			 */
271
-			if (fc->flags & AFS_FS_CURSOR_VMOVED) {
272
-				fc->ac.error = -EREMOTEIO;
245
+			if (op->flags & AFS_OPERATION_VMOVED) {
246
+				op->error = -EREMOTEIO;
273247 				goto failed;
274248 			}
275
-			fc->flags |= AFS_FS_CURSOR_VMOVED;
249
+			op->flags |= AFS_OPERATION_VMOVED;
276250 
277
-			set_bit(AFS_VOLUME_WAIT, &vnode->volume->flags);
278
-			set_bit(AFS_VOLUME_NEEDS_UPDATE, &vnode->volume->flags);
279
-			fc->ac.error = afs_check_volume_status(vnode->volume, fc->key);
280
-			if (fc->ac.error < 0)
281
-				goto failed;
251
+			set_bit(AFS_VOLUME_WAIT, &op->volume->flags);
252
+			set_bit(AFS_VOLUME_NEEDS_UPDATE, &op->volume->flags);
253
+			error = afs_check_volume_status(op->volume, op);
254
+			if (error < 0)
255
+				goto failed_set_error;
282256 
283257 			/* If the server list didn't change, then the VLDB is
284258 			 * out of sync with the fileservers.  This is hopefully
....@@ -289,77 +263,120 @@
289263 			 *
290264 			 * TODO: Retry a few times with sleeps.
291265 			 */
292
-			if (vnode->volume->servers == fc->server_list) {
293
-				fc->ac.error = -ENOMEDIUM;
266
+			if (rcu_access_pointer(op->volume->servers) == op->server_list) {
267
+				op->error = -ENOMEDIUM;
294268 				goto failed;
295269 			}
296270 
297271 			goto restart_from_beginning;
298272 
299273 		default:
300
-			clear_bit(AFS_VOLUME_OFFLINE, &vnode->volume->flags);
301
-			clear_bit(AFS_VOLUME_BUSY, &vnode->volume->flags);
302
-			fc->ac.error = afs_abort_to_error(fc->ac.abort_code);
274
+			clear_bit(AFS_VOLUME_OFFLINE, &op->volume->flags);
275
+			clear_bit(AFS_VOLUME_BUSY, &op->volume->flags);
276
+			op->error = afs_abort_to_error(op->ac.abort_code);
303277 			goto failed;
304278 		}
305279 
306
-	case -ENETUNREACH:
307
-	case -EHOSTUNREACH:
308
-	case -ECONNREFUSED:
309280 	case -ETIMEDOUT:
310281 	case -ETIME:
282
+		if (op->error != -EDESTADDRREQ)
283
+			goto iterate_address;
284
+		fallthrough;
285
+	case -ERFKILL:
286
+	case -EADDRNOTAVAIL:
287
+	case -ENETUNREACH:
288
+	case -EHOSTUNREACH:
289
+	case -EHOSTDOWN:
290
+	case -ECONNREFUSED:
311291 		_debug("no conn");
292
+		op->error = error;
312293 		goto iterate_address;
313294 
314295 	case -ECONNRESET:
315296 		_debug("call reset");
297
+		op->error = error;
316298 		goto failed;
317299 	}
318300 
319301 restart_from_beginning:
320302 	_debug("restart");
321
-	afs_end_cursor(&fc->ac);
322
-	afs_put_cb_interest(afs_v2net(vnode), fc->cbi);
323
-	fc->cbi = NULL;
324
-	afs_put_serverlist(afs_v2net(vnode), fc->server_list);
325
-	fc->server_list = NULL;
303
+	afs_end_cursor(&op->ac);
304
+	op->server = NULL;
305
+	afs_put_serverlist(op->net, op->server_list);
306
+	op->server_list = NULL;
326307 start:
327308 	_debug("start");
328309 	/* See if we need to do an update of the volume record.  Note that the
329310 	 * volume may have moved or even have been deleted.
330311 	 */
331
-	fc->ac.error = afs_check_volume_status(vnode->volume, fc->key);
332
-	if (fc->ac.error < 0)
312
+	error = afs_check_volume_status(op->volume, op);
313
+	if (error < 0)
314
+		goto failed_set_error;
315
+
316
+	if (!afs_start_fs_iteration(op, vnode))
333317 		goto failed;
334318 
335
-	if (!afs_start_fs_iteration(fc, vnode))
336
-		goto failed;
319
+	_debug("__ VOL %llx __", op->volume->vid);
337320 
338
-use_server:
339
-	_debug("use");
321
+pick_server:
322
+	_debug("pick [%lx]", op->untried);
323
+
324
+	error = afs_wait_for_fs_probes(op->server_list, op->untried);
325
+	if (error < 0)
326
+		goto failed_set_error;
327
+
328
+	/* Pick the untried server with the lowest RTT.  If we have outstanding
329
+	 * callbacks, we stick with the server we're already using if we can.
330
+	 */
331
+	if (op->server) {
332
+		_debug("server %u", op->index);
333
+		if (test_bit(op->index, &op->untried))
334
+			goto selected_server;
335
+		op->server = NULL;
336
+		_debug("no server");
337
+	}
338
+
339
+	op->index = -1;
340
+	rtt = U32_MAX;
341
+	for (i = 0; i < op->server_list->nr_servers; i++) {
342
+		struct afs_server *s = op->server_list->servers[i].server;
343
+
344
+		if (!test_bit(i, &op->untried) ||
345
+		    !test_bit(AFS_SERVER_FL_RESPONDING, &s->flags))
346
+			continue;
347
+		if (s->probe.rtt < rtt) {
348
+			op->index = i;
349
+			rtt = s->probe.rtt;
350
+		}
351
+	}
352
+
353
+	if (op->index == -1)
354
+		goto no_more_servers;
355
+
356
+selected_server:
357
+	_debug("use %d", op->index);
358
+	__clear_bit(op->index, &op->untried);
359
+
340360 	/* We're starting on a different fileserver from the list.  We need to
341361 	 * check it, create a callback intercept, find its address list and
342362 	 * probe its capabilities before we use it.
343363 	 */
344
-	ASSERTCMP(fc->ac.alist, ==, NULL);
345
-	server = fc->server_list->servers[fc->index].server;
364
+	ASSERTCMP(op->ac.alist, ==, NULL);
365
+	server = op->server_list->servers[op->index].server;
346366 
347
-	if (!afs_check_server_record(fc, server))
367
+	if (!afs_check_server_record(op, server))
348368 		goto failed;
349369 
350370 	_debug("USING SERVER: %pU", &server->uuid);
351371 
352
-	/* Make sure we've got a callback interest record for this server.  We
353
-	 * have to link it in before we send the request as we can be sent a
354
-	 * break request before we've finished decoding the reply and
355
-	 * installing the vnode.
356
-	 */
357
-	fc->ac.error = afs_register_server_cb_interest(vnode, fc->server_list,
358
-						       fc->index);
359
-	if (fc->ac.error < 0)
360
-		goto failed;
361
-
362
-	fc->cbi = afs_get_cb_interest(vnode->cb_interest);
372
+	op->flags |= AFS_OPERATION_RETRY_SERVER;
373
+	op->server = server;
374
+	if (vnode->cb_server != server) {
375
+		vnode->cb_server = server;
376
+		vnode->cb_s_break = server->cb_s_break;
377
+		vnode->cb_v_break = vnode->volume->cb_v_break;
378
+		clear_bit(AFS_VNODE_CB_PROMISED, &vnode->flags);
379
+	}
363380 
364381 	read_lock(&server->fs_lock);
365382 	alist = rcu_dereference_protected(server->addresses,
....@@ -367,162 +384,130 @@
367384 	afs_get_addrlist(alist);
368385 	read_unlock(&server->fs_lock);
369386 
370
-	memset(&fc->ac, 0, sizeof(fc->ac));
387
+retry_server:
388
+	memset(&op->ac, 0, sizeof(op->ac));
371389 
372
-	/* Probe the current fileserver if we haven't done so yet. */
373
-	if (!test_bit(AFS_SERVER_FL_PROBED, &server->flags)) {
374
-		fc->ac.alist = afs_get_addrlist(alist);
375
-
376
-		if (!afs_probe_fileserver(fc)) {
377
-			switch (fc->ac.error) {
378
-			case -ENOMEM:
379
-			case -ERESTARTSYS:
380
-			case -EINTR:
381
-				goto failed;
382
-			default:
383
-				goto next_server;
384
-			}
385
-		}
386
-	}
387
-
388
-	if (!fc->ac.alist)
389
-		fc->ac.alist = alist;
390
+	if (!op->ac.alist)
391
+		op->ac.alist = alist;
390392 	else
391393 		afs_put_addrlist(alist);
392394 
393
-	fc->ac.start = READ_ONCE(alist->index);
394
-	fc->ac.index = fc->ac.start;
395
+	op->ac.index = -1;
395396 
396397 iterate_address:
397
-	ASSERT(fc->ac.alist);
398
-	_debug("iterate %d/%d", fc->ac.index, fc->ac.alist->nr_addrs);
398
+	ASSERT(op->ac.alist);
399399 	/* Iterate over the current server's address list to try and find an
400400 	 * address on which it will respond to us.
401401 	 */
402
-	if (!afs_iterate_addresses(&fc->ac))
403
-		goto next_server;
402
+	if (!afs_iterate_addresses(&op->ac))
403
+		goto out_of_addresses;
404
+
405
+	_debug("address [%u] %u/%u %pISp",
406
+	       op->index, op->ac.index, op->ac.alist->nr_addrs,
407
+	       &op->ac.alist->addrs[op->ac.index].transport);
404408 
405409 	_leave(" = t");
406410 	return true;
407411 
412
+out_of_addresses:
413
+	/* We've now had a failure to respond on all of a server's addresses -
414
+	 * immediately probe them again and consider retrying the server.
415
+	 */
416
+	afs_probe_fileserver(op->net, op->server);
417
+	if (op->flags & AFS_OPERATION_RETRY_SERVER) {
418
+		alist = op->ac.alist;
419
+		error = afs_wait_for_one_fs_probe(
420
+			op->server, !(op->flags & AFS_OPERATION_UNINTR));
421
+		switch (error) {
422
+		case 0:
423
+			op->flags &= ~AFS_OPERATION_RETRY_SERVER;
424
+			goto retry_server;
425
+		case -ERESTARTSYS:
426
+			goto failed_set_error;
427
+		case -ETIME:
428
+		case -EDESTADDRREQ:
429
+			goto next_server;
430
+		}
431
+	}
432
+
408433 next_server:
409434 	_debug("next");
410
-	afs_end_cursor(&fc->ac);
411
-	afs_put_cb_interest(afs_v2net(vnode), fc->cbi);
412
-	fc->cbi = NULL;
413
-	fc->index++;
414
-	if (fc->index >= fc->server_list->nr_servers)
415
-		fc->index = 0;
416
-	if (fc->index != fc->start)
417
-		goto use_server;
435
+	afs_end_cursor(&op->ac);
436
+	goto pick_server;
418437 
438
+no_more_servers:
419439 	/* That's all the servers poked to no good effect.  Try again if some
420440 	 * of them were busy.
421441 	 */
422
-	if (fc->flags & AFS_FS_CURSOR_VBUSY)
442
+	if (op->flags & AFS_OPERATION_VBUSY)
423443 		goto restart_from_beginning;
424444 
425
-	fc->ac.error = -EDESTADDRREQ;
426
-	goto failed;
445
+	e.error = -EDESTADDRREQ;
446
+	e.responded = false;
447
+	for (i = 0; i < op->server_list->nr_servers; i++) {
448
+		struct afs_server *s = op->server_list->servers[i].server;
427449 
450
+		afs_prioritise_error(&e, READ_ONCE(s->probe.error),
451
+				     s->probe.abort_code);
452
+	}
453
+
454
+	error = e.error;
455
+
456
+failed_set_error:
457
+	op->error = error;
428458 failed:
429
-	fc->flags |= AFS_FS_CURSOR_STOP;
430
-	afs_end_cursor(&fc->ac);
431
-	_leave(" = f [failed %d]", fc->ac.error);
459
+	op->flags |= AFS_OPERATION_STOP;
460
+	afs_end_cursor(&op->ac);
461
+	_leave(" = f [failed %d]", op->error);
432462 	return false;
433463 }
434464 
435465 /*
436
- * Select the same fileserver we used for a vnode before and only that
437
- * fileserver.  We use this when we have a lock on that file, which is backed
438
- * only by the fileserver we obtained it from.
466
+ * Dump cursor state in the case of the error being EDESTADDRREQ.
439467  */
440
-bool afs_select_current_fileserver(struct afs_fs_cursor *fc)
468
+void afs_dump_edestaddrreq(const struct afs_operation *op)
441469 {
442
-	struct afs_vnode *vnode = fc->vnode;
443
-	struct afs_cb_interest *cbi = vnode->cb_interest;
444
-	struct afs_addr_list *alist;
470
+	static int count;
471
+	int i;
445472 
446
-	_enter("");
473
+	if (!IS_ENABLED(CONFIG_AFS_DEBUG_CURSOR) || count > 3)
474
+		return;
475
+	count++;
447476 
448
-	switch (fc->ac.error) {
449
-	case SHRT_MAX:
450
-		if (!cbi) {
451
-			fc->ac.error = -ESTALE;
452
-			fc->flags |= AFS_FS_CURSOR_STOP;
453
-			return false;
477
+	rcu_read_lock();
478
+
479
+	pr_notice("EDESTADDR occurred\n");
480
+	pr_notice("FC: cbb=%x cbb2=%x fl=%x err=%hd\n",
481
+		  op->file[0].cb_break_before,
482
+		  op->file[1].cb_break_before, op->flags, op->error);
483
+	pr_notice("FC: ut=%lx ix=%d ni=%u\n",
484
+		  op->untried, op->index, op->nr_iterations);
485
+
486
+	if (op->server_list) {
487
+		const struct afs_server_list *sl = op->server_list;
488
+		pr_notice("FC: SL nr=%u pr=%u vnov=%hx\n",
489
+			  sl->nr_servers, sl->preferred, sl->vnovol_mask);
490
+		for (i = 0; i < sl->nr_servers; i++) {
491
+			const struct afs_server *s = sl->servers[i].server;
492
+			pr_notice("FC: server fl=%lx av=%u %pU\n",
493
+				  s->flags, s->addr_version, &s->uuid);
494
+			if (s->addresses) {
495
+				const struct afs_addr_list *a =
496
+					rcu_dereference(s->addresses);
497
+				pr_notice("FC:  - av=%u nr=%u/%u/%u pr=%u\n",
498
+					  a->version,
499
+					  a->nr_ipv4, a->nr_addrs, a->max_addrs,
500
+					  a->preferred);
501
+				pr_notice("FC:  - R=%lx F=%lx\n",
502
+					  a->responded, a->failed);
503
+				if (a == op->ac.alist)
504
+					pr_notice("FC:  - current\n");
505
+			}
454506 		}
455
-
456
-		fc->cbi = afs_get_cb_interest(vnode->cb_interest);
457
-
458
-		read_lock(&cbi->server->fs_lock);
459
-		alist = rcu_dereference_protected(cbi->server->addresses,
460
-						  lockdep_is_held(&cbi->server->fs_lock));
461
-		afs_get_addrlist(alist);
462
-		read_unlock(&cbi->server->fs_lock);
463
-		if (!alist) {
464
-			fc->ac.error = -ESTALE;
465
-			fc->flags |= AFS_FS_CURSOR_STOP;
466
-			return false;
467
-		}
468
-
469
-		memset(&fc->ac, 0, sizeof(fc->ac));
470
-		fc->ac.alist = alist;
471
-		fc->ac.start = READ_ONCE(alist->index);
472
-		fc->ac.index = fc->ac.start;
473
-		goto iterate_address;
474
-
475
-	case 0:
476
-	default:
477
-		/* Success or local failure.  Stop. */
478
-		fc->flags |= AFS_FS_CURSOR_STOP;
479
-		_leave(" = f [okay/local %d]", fc->ac.error);
480
-		return false;
481
-
482
-	case -ECONNABORTED:
483
-		fc->flags |= AFS_FS_CURSOR_STOP;
484
-		_leave(" = f [abort]");
485
-		return false;
486
-
487
-	case -ENETUNREACH:
488
-	case -EHOSTUNREACH:
489
-	case -ECONNREFUSED:
490
-	case -ETIMEDOUT:
491
-	case -ETIME:
492
-		_debug("no conn");
493
-		goto iterate_address;
494507 	}
495508 
496
-iterate_address:
497
-	/* Iterate over the current server's address list to try and find an
498
-	 * address on which it will respond to us.
499
-	 */
500
-	if (afs_iterate_addresses(&fc->ac)) {
501
-		_leave(" = t");
502
-		return true;
503
-	}
504
-
505
-	afs_end_cursor(&fc->ac);
506
-	return false;
507
-}
508
-
509
-/*
510
- * Tidy up a filesystem cursor and unlock the vnode.
511
- */
512
-int afs_end_vnode_operation(struct afs_fs_cursor *fc)
513
-{
514
-	struct afs_net *net = afs_v2net(fc->vnode);
515
-	int ret;
516
-
517
-	mutex_unlock(&fc->vnode->io_lock);
518
-
519
-	afs_end_cursor(&fc->ac);
520
-	afs_put_cb_interest(net, fc->cbi);
521
-	afs_put_serverlist(net, fc->server_list);
522
-
523
-	ret = fc->ac.error;
524
-	if (ret == -ECONNABORTED)
525
-		afs_abort_to_error(fc->ac.abort_code);
526
-
527
-	return fc->ac.error;
509
+	pr_notice("AC: t=%lx ax=%u ac=%d er=%d r=%u ni=%u\n",
510
+		  op->ac.tried, op->ac.index, op->ac.abort_code, op->ac.error,
511
+		  op->ac.responded, op->ac.nr_iterations);
512
+	rcu_read_unlock();
528513 }