[thirdparty/linux.git] / fs / afs / fs_probe.c

// SPDX-License-Identifier: GPL-2.0-or-later
/* AFS fileserver probing
 *
 * Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 */

#include <linux/sched.h>
#include <linux/slab.h>
#include "afs_fs.h"
#include "internal.h"
#include "protocol_yfs.h"

static bool afs_fs_probe_done(struct afs_server *server)
{
	if (!atomic_dec_and_test(&server->probe_outstanding))
		return false;

	wake_up_var(&server->probe_outstanding);
	clear_bit_unlock(AFS_SERVER_FL_PROBING, &server->flags);
	wake_up_bit(&server->flags, AFS_SERVER_FL_PROBING);
	return true;
}

/*
 * Process the result of probing a fileserver.  This is called after successful
 * or failed delivery of an FS.GetCapabilities operation.
 */
void afs_fileserver_probe_result(struct afs_call *call)
{
	struct afs_addr_list *alist = call->alist;
	struct afs_server *server = call->server;
	unsigned int server_index = call->server_index;
	unsigned int index = call->addr_ix;
	unsigned int rtt_us = 0;
	bool have_result = false;
	int ret = call->error;

	_enter("%pU,%u", &server->uuid, index);

	spin_lock(&server->probe_lock);

	switch (ret) {
	case 0:
		server->probe.error = 0;
		goto responded;
	case -ECONNABORTED:
		if (!server->probe.responded) {
			server->probe.abort_code = call->abort_code;
			server->probe.error = ret;
		}
		goto responded;
	case -ENOMEM:
	case -ENONET:
		server->probe.local_failure = true;
		afs_io_error(call, afs_io_error_fs_probe_fail);
		goto out;
	case -ECONNRESET: /* Responded, but call expired. */
	case -ERFKILL:
	case -EADDRNOTAVAIL:
	case -ENETUNREACH:
	case -EHOSTUNREACH:
	case -EHOSTDOWN:
	case -ECONNREFUSED:
	case -ETIMEDOUT:
	case -ETIME:
	default:
		clear_bit(index, &alist->responded);
		set_bit(index, &alist->failed);
		if (!server->probe.responded &&
		    (server->probe.error == 0 ||
		     server->probe.error == -ETIMEDOUT ||
		     server->probe.error == -ETIME))
			server->probe.error = ret;
		afs_io_error(call, afs_io_error_fs_probe_fail);
		goto out;
	}

responded:
	set_bit(index, &alist->responded);
	clear_bit(index, &alist->failed);

	if (call->service_id == YFS_FS_SERVICE) {
		server->probe.is_yfs = true;
		set_bit(AFS_SERVER_FL_IS_YFS, &server->flags);
		alist->addrs[index].srx_service = call->service_id;
	} else {
		server->probe.not_yfs = true;
		if (!server->probe.is_yfs) {
			clear_bit(AFS_SERVER_FL_IS_YFS, &server->flags);
			alist->addrs[index].srx_service = call->service_id;
		}
	}

	rtt_us = rxrpc_kernel_get_srtt(call->net->socket, call->rxcall);
	if (rtt_us < server->probe.rtt) {
		server->probe.rtt = rtt_us;
		alist->preferred = index;
		have_result = true;
	}

	smp_wmb(); /* Set rtt before responded. */
	server->probe.responded = true;
	set_bit(AFS_SERVER_FL_PROBED, &server->flags);
out:
	spin_unlock(&server->probe_lock);

	_debug("probe [%u][%u] %pISpc rtt=%u ret=%d",
	       server_index, index, &alist->addrs[index].transport, rtt_us, ret);

	have_result |= afs_fs_probe_done(server);
	if (have_result)
		wake_up_all(&server->probe_wq);
}

/*
 * Probe all of a fileserver's addresses to find out the best route and to
 * query its capabilities.
 */
static int afs_do_probe_fileserver(struct afs_net *net,
				   struct afs_server *server,
				   struct key *key,
				   unsigned int server_index,
				   struct afs_error *_e)
{
	struct afs_addr_cursor ac = {
		.index = 0,
	};
	struct afs_call *call;
	bool in_progress = false;

	_enter("%pU", &server->uuid);

	read_lock(&server->fs_lock);
	ac.alist = rcu_dereference_protected(server->addresses,
					     lockdep_is_held(&server->fs_lock));
	afs_get_addrlist(ac.alist);
	read_unlock(&server->fs_lock);

	atomic_set(&server->probe_outstanding, ac.alist->nr_addrs);
	memset(&server->probe, 0, sizeof(server->probe));
	server->probe.rtt = UINT_MAX;

	for (ac.index = 0; ac.index < ac.alist->nr_addrs; ac.index++) {
		call = afs_fs_get_capabilities(net, server, &ac, key, server_index);
		if (!IS_ERR(call)) {
			afs_put_call(call);
			in_progress = true;
		} else {
			afs_prioritise_error(_e, PTR_ERR(call), ac.abort_code);
		}
	}

	if (!in_progress)
		afs_fs_probe_done(server);
	afs_put_addrlist(ac.alist);
	return in_progress;
}

/*
 * Send off probes to all unprobed servers.
 */
int afs_probe_fileservers(struct afs_net *net, struct key *key,
			  struct afs_server_list *list)
{
	struct afs_server *server;
	struct afs_error e;
	bool in_progress = false;
	int i;

	e.error = 0;
	e.responded = false;
	for (i = 0; i < list->nr_servers; i++) {
		server = list->servers[i].server;
		if (test_bit(AFS_SERVER_FL_PROBED, &server->flags))
			continue;

		if (!test_and_set_bit_lock(AFS_SERVER_FL_PROBING, &server->flags) &&
		    afs_do_probe_fileserver(net, server, key, i, &e))
			in_progress = true;
	}

	return in_progress ? 0 : e.error;
}

/*
 * Wait for the first as-yet untried fileserver to respond.
 */
int afs_wait_for_fs_probes(struct afs_server_list *slist, unsigned long untried)
{
	struct wait_queue_entry *waits;
	struct afs_server *server;
	unsigned int rtt = UINT_MAX;
	bool have_responders = false;
	int pref = -1, i;

	_enter("%u,%lx", slist->nr_servers, untried);

	/* Only wait for servers that have a probe outstanding. */
	for (i = 0; i < slist->nr_servers; i++) {
		if (test_bit(i, &untried)) {
			server = slist->servers[i].server;
			if (!test_bit(AFS_SERVER_FL_PROBING, &server->flags))
				__clear_bit(i, &untried);
			if (server->probe.responded)
				have_responders = true;
		}
	}
	if (have_responders || !untried)
		return 0;

	waits = kmalloc(array_size(slist->nr_servers, sizeof(*waits)), GFP_KERNEL);
	if (!waits)
		return -ENOMEM;

	for (i = 0; i < slist->nr_servers; i++) {
		if (test_bit(i, &untried)) {
			server = slist->servers[i].server;
			init_waitqueue_entry(&waits[i], current);
			add_wait_queue(&server->probe_wq, &waits[i]);
		}
	}

	for (;;) {
		bool still_probing = false;

		set_current_state(TASK_INTERRUPTIBLE);
		for (i = 0; i < slist->nr_servers; i++) {
			if (test_bit(i, &untried)) {
				server = slist->servers[i].server;
				if (server->probe.responded)
					goto stop;
				if (test_bit(AFS_SERVER_FL_PROBING, &server->flags))
					still_probing = true;
			}
		}

		if (!still_probing || signal_pending(current))
			goto stop;
		schedule();
	}

stop:
	set_current_state(TASK_RUNNING);

	for (i = 0; i < slist->nr_servers; i++) {
		if (test_bit(i, &untried)) {
			server = slist->servers[i].server;
			if (server->probe.responded &&
			    server->probe.rtt < rtt) {
				pref = i;
				rtt = server->probe.rtt;
			}

			remove_wait_queue(&server->probe_wq, &waits[i]);
		}
	}

	kfree(waits);

	if (pref == -1 && signal_pending(current))
		return -ERESTARTSYS;

	if (pref >= 0)
		slist->preferred = pref;
	return 0;
}
Commit	Line	Data
b4d0d230	1	// SPDX-License-Identifier: GPL-2.0-or-later
3bf0fb6f DH	2	/* AFS fileserver probing
	3	*
	4	* Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.
	5	* Written by David Howells (dhowells@redhat.com)
3bf0fb6f DH	6	*/
	7
	8	#include <linux/sched.h>
	9	#include <linux/slab.h>
	10	#include "afs_fs.h"
	11	#include "internal.h"
	12	#include "protocol_yfs.h"
	13
	14	static bool afs_fs_probe_done(struct afs_server *server)
	15	{
	16	if (!atomic_dec_and_test(&server->probe_outstanding))
	17	return false;
	18
	19	wake_up_var(&server->probe_outstanding);
	20	clear_bit_unlock(AFS_SERVER_FL_PROBING, &server->flags);
	21	wake_up_bit(&server->flags, AFS_SERVER_FL_PROBING);
	22	return true;
	23	}
	24
	25	/*
	26	* Process the result of probing a fileserver. This is called after successful
	27	* or failed delivery of an FS.GetCapabilities operation.
	28	*/
	29	void afs_fileserver_probe_result(struct afs_call *call)
	30	{
	31	struct afs_addr_list *alist = call->alist;
ffba718e DH	32	struct afs_server *server = call->server;
ffba718e DH	33	unsigned int server_index = call->server_index;
3bf0fb6f	34	unsigned int index = call->addr_ix;
8a1d24e1	35	unsigned int rtt_us = 0;
3bf0fb6f	36	bool have_result = false;
3bf0fb6f DH	37	int ret = call->error;
	38
	39	_enter("%pU,%u", &server->uuid, index);
	40
	41	spin_lock(&server->probe_lock);
	42
	43	switch (ret) {
	44	case 0:
	45	server->probe.error = 0;
	46	goto responded;
	47	case -ECONNABORTED:
	48	if (!server->probe.responded) {
	49	server->probe.abort_code = call->abort_code;
	50	server->probe.error = ret;
	51	}
	52	goto responded;
	53	case -ENOMEM:
	54	case -ENONET:
	55	server->probe.local_failure = true;
	56	afs_io_error(call, afs_io_error_fs_probe_fail);
	57	goto out;
	58	case -ECONNRESET: /* Responded, but call expired. */
4584ae96 DH	59	case -ERFKILL:
4584ae96 DH	60	case -EADDRNOTAVAIL:
3bf0fb6f DH	61	case -ENETUNREACH:
3bf0fb6f DH	62	case -EHOSTUNREACH:
4584ae96	63	case -EHOSTDOWN:
3bf0fb6f DH	64	case -ECONNREFUSED:
	65	case -ETIMEDOUT:
	66	case -ETIME:
	67	default:
	68	clear_bit(index, &alist->responded);
	69	set_bit(index, &alist->failed);
	70	if (!server->probe.responded &&
	71	(server->probe.error == 0 \|\|
	72	server->probe.error == -ETIMEDOUT \|\|
	73	server->probe.error == -ETIME))
	74	server->probe.error = ret;
	75	afs_io_error(call, afs_io_error_fs_probe_fail);
	76	goto out;
	77	}
	78
	79	responded:
	80	set_bit(index, &alist->responded);
	81	clear_bit(index, &alist->failed);
	82
	83	if (call->service_id == YFS_FS_SERVICE) {
	84	server->probe.is_yfs = true;
	85	set_bit(AFS_SERVER_FL_IS_YFS, &server->flags);
	86	alist->addrs[index].srx_service = call->service_id;
	87	} else {
	88	server->probe.not_yfs = true;
	89	if (!server->probe.is_yfs) {
	90	clear_bit(AFS_SERVER_FL_IS_YFS, &server->flags);
	91	alist->addrs[index].srx_service = call->service_id;
	92	}
	93	}
	94
c410bf01 DH	95	rtt_us = rxrpc_kernel_get_srtt(call->net->socket, call->rxcall);
	96	if (rtt_us < server->probe.rtt) {
	97	server->probe.rtt = rtt_us;
3bf0fb6f DH	98	alist->preferred = index;
	99	have_result = true;
	100	}
	101
	102	smp_wmb(); /* Set rtt before responded. */
	103	server->probe.responded = true;
	104	set_bit(AFS_SERVER_FL_PROBED, &server->flags);
	105	out:
	106	spin_unlock(&server->probe_lock);
	107
	108	_debug("probe [%u][%u] %pISpc rtt=%u ret=%d",
c410bf01	109	server_index, index, &alist->addrs[index].transport, rtt_us, ret);
3bf0fb6f DH	110
3bf0fb6f DH	111	have_result \|= afs_fs_probe_done(server);
be59167c	112	if (have_result)
3bf0fb6f	113	wake_up_all(&server->probe_wq);
3bf0fb6f DH	114	}
	115
	116	/*
	117	* Probe all of a fileserver's addresses to find out the best route and to
	118	* query its capabilities.
	119	*/
	120	static int afs_do_probe_fileserver(struct afs_net *net,
	121	struct afs_server *server,
	122	struct key *key,
4584ae96 DH	123	unsigned int server_index,
4584ae96 DH	124	struct afs_error *_e)
3bf0fb6f DH	125	{
	126	struct afs_addr_cursor ac = {
	127	.index = 0,
	128	};
0b9bf381	129	struct afs_call *call;
4584ae96	130	bool in_progress = false;
3bf0fb6f DH	131
	132	_enter("%pU", &server->uuid);
	133
	134	read_lock(&server->fs_lock);
	135	ac.alist = rcu_dereference_protected(server->addresses,
	136	lockdep_is_held(&server->fs_lock));
9efcc4a1	137	afs_get_addrlist(ac.alist);
3bf0fb6f DH	138	read_unlock(&server->fs_lock);
	139
	140	atomic_set(&server->probe_outstanding, ac.alist->nr_addrs);
	141	memset(&server->probe, 0, sizeof(server->probe));
	142	server->probe.rtt = UINT_MAX;
	143
	144	for (ac.index = 0; ac.index < ac.alist->nr_addrs; ac.index++) {
0b9bf381 DH	145	call = afs_fs_get_capabilities(net, server, &ac, key, server_index);
	146	if (!IS_ERR(call)) {
	147	afs_put_call(call);
4584ae96	148	in_progress = true;
0b9bf381 DH	149	} else {
	150	afs_prioritise_error(_e, PTR_ERR(call), ac.abort_code);
	151	}
3bf0fb6f DH	152	}
3bf0fb6f DH	153
4584ae96 DH	154	if (!in_progress)
4584ae96 DH	155	afs_fs_probe_done(server);
9efcc4a1	156	afs_put_addrlist(ac.alist);
4584ae96	157	return in_progress;
3bf0fb6f DH	158	}
	159
	160	/*
	161	* Send off probes to all unprobed servers.
	162	*/
	163	int afs_probe_fileservers(struct afs_net net, struct key key,
	164	struct afs_server_list *list)
	165	{
	166	struct afs_server *server;
4584ae96 DH	167	struct afs_error e;
	168	bool in_progress = false;
	169	int i;
3bf0fb6f	170
4584ae96 DH	171	e.error = 0;
4584ae96 DH	172	e.responded = false;
3bf0fb6f DH	173	for (i = 0; i < list->nr_servers; i++) {
	174	server = list->servers[i].server;
	175	if (test_bit(AFS_SERVER_FL_PROBED, &server->flags))
	176	continue;
	177
4584ae96 DH	178	if (!test_and_set_bit_lock(AFS_SERVER_FL_PROBING, &server->flags) &&
	179	afs_do_probe_fileserver(net, server, key, i, &e))
	180	in_progress = true;
3bf0fb6f DH	181	}
3bf0fb6f DH	182
4584ae96	183	return in_progress ? 0 : e.error;
3bf0fb6f DH	184	}
	185
	186	/*
	187	* Wait for the first as-yet untried fileserver to respond.
	188	*/
	189	int afs_wait_for_fs_probes(struct afs_server_list *slist, unsigned long untried)
	190	{
	191	struct wait_queue_entry *waits;
	192	struct afs_server *server;
	193	unsigned int rtt = UINT_MAX;
	194	bool have_responders = false;
	195	int pref = -1, i;
	196
	197	_enter("%u,%lx", slist->nr_servers, untried);
	198
	199	/* Only wait for servers that have a probe outstanding. */
	200	for (i = 0; i < slist->nr_servers; i++) {
	201	if (test_bit(i, &untried)) {
	202	server = slist->servers[i].server;
	203	if (!test_bit(AFS_SERVER_FL_PROBING, &server->flags))
	204	__clear_bit(i, &untried);
	205	if (server->probe.responded)
	206	have_responders = true;
	207	}
	208	}
	209	if (have_responders \|\| !untried)
	210	return 0;
	211
	212	waits = kmalloc(array_size(slist->nr_servers, sizeof(*waits)), GFP_KERNEL);
	213	if (!waits)
	214	return -ENOMEM;
	215
	216	for (i = 0; i < slist->nr_servers; i++) {
	217	if (test_bit(i, &untried)) {
	218	server = slist->servers[i].server;
	219	init_waitqueue_entry(&waits[i], current);
	220	add_wait_queue(&server->probe_wq, &waits[i]);
	221	}
	222	}
	223
	224	for (;;) {
	225	bool still_probing = false;
	226
	227	set_current_state(TASK_INTERRUPTIBLE);
	228	for (i = 0; i < slist->nr_servers; i++) {
	229	if (test_bit(i, &untried)) {
	230	server = slist->servers[i].server;
	231	if (server->probe.responded)
	232	goto stop;
	233	if (test_bit(AFS_SERVER_FL_PROBING, &server->flags))
	234	still_probing = true;
	235	}
	236	}
	237
08d405c8	238	if (!still_probing \|\| signal_pending(current))
3bf0fb6f DH	239	goto stop;
	240	schedule();
	241	}
	242
	243	stop:
	244	set_current_state(TASK_RUNNING);
	245
	246	for (i = 0; i < slist->nr_servers; i++) {
	247	if (test_bit(i, &untried)) {
	248	server = slist->servers[i].server;
	249	if (server->probe.responded &&
	250	server->probe.rtt < rtt) {
	251	pref = i;
	252	rtt = server->probe.rtt;
	253	}
	254
	255	remove_wait_queue(&server->probe_wq, &waits[i]);
	256	}
	257	}
	258
	259	kfree(waits);
	260
	261	if (pref == -1 && signal_pending(current))
	262	return -ERESTARTSYS;
	263
	264	if (pref >= 0)
	265	slist->preferred = pref;
	266	return 0;
	267	}