[linux.git] / fs / afs / volume.c

/* AFS volume management
 *
 * Copyright (C) 2002, 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells ([email protected])
 *
 * 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/kernel.h>
#include <linux/slab.h>
#include "internal.h"

unsigned __read_mostly afs_volume_gc_delay = 10;
unsigned __read_mostly afs_volume_record_life = 60 * 60;

static const char *const afs_voltypes[] = { "R/W", "R/O", "BAK" };

/*
 * Allocate a volume record and load it up from a vldb record.
 */
static struct afs_volume *afs_alloc_volume(struct afs_mount_params *params,
					   struct afs_vldb_entry *vldb,
					   unsigned long type_mask)
{
	struct afs_server_list *slist;
	struct afs_volume *volume;
	int ret = -ENOMEM, nr_servers = 0, i;

	for (i = 0; i < vldb->nr_servers; i++)
		if (vldb->fs_mask[i] & type_mask)
			nr_servers++;

	volume = kzalloc(sizeof(struct afs_volume), GFP_KERNEL);
	if (!volume)
		goto error_0;

	volume->vid		= vldb->vid[params->type];
	volume->update_at	= ktime_get_real_seconds() + afs_volume_record_life;
	volume->cell		= afs_get_cell(params->cell);
	volume->type		= params->type;
	volume->type_force	= params->force;
	volume->name_len	= vldb->name_len;

	atomic_set(&volume->usage, 1);
	INIT_LIST_HEAD(&volume->proc_link);
	rwlock_init(&volume->servers_lock);
	memcpy(volume->name, vldb->name, vldb->name_len + 1);

	slist = afs_alloc_server_list(params->cell, params->key, vldb, type_mask);
	if (IS_ERR(slist)) {
		ret = PTR_ERR(slist);
		goto error_1;
	}

	refcount_set(&slist->usage, 1);
	volume->servers = slist;
	return volume;

error_1:
	afs_put_cell(params->net, volume->cell);
	kfree(volume);
error_0:
	return ERR_PTR(ret);
}

/*
 * Look up a VLDB record for a volume.
 */
static struct afs_vldb_entry *afs_vl_lookup_vldb(struct afs_cell *cell,
						 struct key *key,
						 const char *volname,
						 size_t volnamesz)
{
	struct afs_addr_cursor ac;
	struct afs_vldb_entry *vldb;
	int ret;

	ret = afs_set_vl_cursor(&ac, cell);
	if (ret < 0)
		return ERR_PTR(ret);

	while (afs_iterate_addresses(&ac)) {
		if (!test_bit(ac.index, &ac.alist->probed)) {
			ret = afs_vl_get_capabilities(cell->net, &ac, key);
			switch (ret) {
			case VL_SERVICE:
				clear_bit(ac.index, &ac.alist->yfs);
				set_bit(ac.index, &ac.alist->probed);
				ac.addr->srx_service = ret;
				break;
			case YFS_VL_SERVICE:
				set_bit(ac.index, &ac.alist->yfs);
				set_bit(ac.index, &ac.alist->probed);
				ac.addr->srx_service = ret;
				break;
			}
		}
		
		vldb = afs_vl_get_entry_by_name_u(cell->net, &ac, key,
						  volname, volnamesz);
		switch (ac.error) {
		case 0:
			afs_end_cursor(&ac);
			return vldb;
		case -ECONNABORTED:
			ac.error = afs_abort_to_error(ac.abort_code);
			goto error;
		case -ENOMEM:
		case -ENONET:
			goto error;
		case -ENETUNREACH:
		case -EHOSTUNREACH:
		case -ECONNREFUSED:
			break;
		default:
			ac.error = -EIO;
			goto error;
		}
	}

error:
	return ERR_PTR(afs_end_cursor(&ac));
}

/*
 * Look up a volume in the VL server and create a candidate volume record for
 * it.
 *
 * The volume name can be one of the following:
 *	"%[cell:]volume[.]"		R/W volume
 *	"#[cell:]volume[.]"		R/O or R/W volume (rwparent=0),
 *					 or R/W (rwparent=1) volume
 *	"%[cell:]volume.readonly"	R/O volume
 *	"#[cell:]volume.readonly"	R/O volume
 *	"%[cell:]volume.backup"		Backup volume
 *	"#[cell:]volume.backup"		Backup volume
 *
 * The cell name is optional, and defaults to the current cell.
 *
 * See "The Rules of Mount Point Traversal" in Chapter 5 of the AFS SysAdmin
 * Guide
 * - Rule 1: Explicit type suffix forces access of that type or nothing
 *           (no suffix, then use Rule 2 & 3)
 * - Rule 2: If parent volume is R/O, then mount R/O volume by preference, R/W
 *           if not available
 * - Rule 3: If parent volume is R/W, then only mount R/W volume unless
 *           explicitly told otherwise
 */
struct afs_volume *afs_create_volume(struct afs_mount_params *params)
{
	struct afs_vldb_entry *vldb;
	struct afs_volume *volume;
	unsigned long type_mask = 1UL << params->type;

	vldb = afs_vl_lookup_vldb(params->cell, params->key,
				  params->volname, params->volnamesz);
	if (IS_ERR(vldb))
		return ERR_CAST(vldb);

	if (test_bit(AFS_VLDB_QUERY_ERROR, &vldb->flags)) {
		volume = ERR_PTR(vldb->error);
		goto error;
	}

	/* Make the final decision on the type we want */
	volume = ERR_PTR(-ENOMEDIUM);
	if (params->force) {
		if (!(vldb->flags & type_mask))
			goto error;
	} else if (test_bit(AFS_VLDB_HAS_RO, &vldb->flags)) {
		params->type = AFSVL_ROVOL;
	} else if (test_bit(AFS_VLDB_HAS_RW, &vldb->flags)) {
		params->type = AFSVL_RWVOL;
	} else {
		goto error;
	}

	type_mask = 1UL << params->type;
	volume = afs_alloc_volume(params, vldb, type_mask);

error:
	kfree(vldb);
	return volume;
}

/*
 * Destroy a volume record
 */
static void afs_destroy_volume(struct afs_net *net, struct afs_volume *volume)
{
	_enter("%p", volume);

#ifdef CONFIG_AFS_FSCACHE
	ASSERTCMP(volume->cache, ==, NULL);
#endif

	afs_put_serverlist(net, volume->servers);
	afs_put_cell(net, volume->cell);
	kfree(volume);

	_leave(" [destroyed]");
}

/*
 * Drop a reference on a volume record.
 */
void afs_put_volume(struct afs_cell *cell, struct afs_volume *volume)
{
	if (volume) {
		_enter("%s", volume->name);

		if (atomic_dec_and_test(&volume->usage))
			afs_destroy_volume(cell->net, volume);
	}
}

/*
 * Activate a volume.
 */
void afs_activate_volume(struct afs_volume *volume)
{
#ifdef CONFIG_AFS_FSCACHE
	volume->cache = fscache_acquire_cookie(volume->cell->cache,
					       &afs_volume_cache_index_def,
					       &volume->vid, sizeof(volume->vid),
					       NULL, 0,
					       volume, 0, true);
#endif

	write_lock(&volume->cell->proc_lock);
	list_add_tail(&volume->proc_link, &volume->cell->proc_volumes);
	write_unlock(&volume->cell->proc_lock);
}

/*
 * Deactivate a volume.
 */
void afs_deactivate_volume(struct afs_volume *volume)
{
	_enter("%s", volume->name);

	write_lock(&volume->cell->proc_lock);
	list_del_init(&volume->proc_link);
	write_unlock(&volume->cell->proc_lock);

#ifdef CONFIG_AFS_FSCACHE
	fscache_relinquish_cookie(volume->cache, NULL,
				  test_bit(AFS_VOLUME_DELETED, &volume->flags));
	volume->cache = NULL;
#endif

	_leave("");
}

/*
 * Query the VL service to update the volume status.
 */
static int afs_update_volume_status(struct afs_volume *volume, struct key *key)
{
	struct afs_server_list *new, *old, *discard;
	struct afs_vldb_entry *vldb;
	char idbuf[16];
	int ret, idsz;

	_enter("");

	/* We look up an ID by passing it as a decimal string in the
	 * operation's name parameter.
	 */
	idsz = sprintf(idbuf, "%u", volume->vid);

	vldb = afs_vl_lookup_vldb(volume->cell, key, idbuf, idsz);
	if (IS_ERR(vldb)) {
		ret = PTR_ERR(vldb);
		goto error;
	}

	/* See if the volume got renamed. */
	if (vldb->name_len != volume->name_len ||
	    memcmp(vldb->name, volume->name, vldb->name_len) != 0) {
		/* TODO: Use RCU'd string. */
		memcpy(volume->name, vldb->name, AFS_MAXVOLNAME);
		volume->name_len = vldb->name_len;
	}

	/* See if the volume's server list got updated. */
	new = afs_alloc_server_list(volume->cell, key,
				    vldb, (1 << volume->type));
	if (IS_ERR(new)) {
		ret = PTR_ERR(new);
		goto error_vldb;
	}

	write_lock(&volume->servers_lock);

	discard = new;
	old = volume->servers;
	if (afs_annotate_server_list(new, old)) {
		new->seq = volume->servers_seq + 1;
		volume->servers = new;
		smp_wmb();
		volume->servers_seq++;
		discard = old;
	}

	volume->update_at = ktime_get_real_seconds() + afs_volume_record_life;
	clear_bit(AFS_VOLUME_NEEDS_UPDATE, &volume->flags);
	write_unlock(&volume->servers_lock);
	ret = 0;

	afs_put_serverlist(volume->cell->net, discard);
error_vldb:
	kfree(vldb);
error:
	_leave(" = %d", ret);
	return ret;
}

/*
 * Make sure the volume record is up to date.
 */
int afs_check_volume_status(struct afs_volume *volume, struct key *key)
{
	time64_t now = ktime_get_real_seconds();
	int ret, retries = 0;

	_enter("");

	if (volume->update_at <= now)
		set_bit(AFS_VOLUME_NEEDS_UPDATE, &volume->flags);

retry:
	if (!test_bit(AFS_VOLUME_NEEDS_UPDATE, &volume->flags) &&
	    !test_bit(AFS_VOLUME_WAIT, &volume->flags)) {
		_leave(" = 0");
		return 0;
	}

	if (!test_and_set_bit_lock(AFS_VOLUME_UPDATING, &volume->flags)) {
		ret = afs_update_volume_status(volume, key);
		clear_bit_unlock(AFS_VOLUME_WAIT, &volume->flags);
		clear_bit_unlock(AFS_VOLUME_UPDATING, &volume->flags);
		wake_up_bit(&volume->flags, AFS_VOLUME_WAIT);
		_leave(" = %d", ret);
		return ret;
	}

	if (!test_bit(AFS_VOLUME_WAIT, &volume->flags)) {
		_leave(" = 0 [no wait]");
		return 0;
	}

	ret = wait_on_bit(&volume->flags, AFS_VOLUME_WAIT, TASK_INTERRUPTIBLE);
	if (ret == -ERESTARTSYS) {
		_leave(" = %d", ret);
		return ret;
	}

	retries++;
	if (retries == 4) {
		_leave(" = -ESTALE");
		return -ESTALE;
	}
	goto retry;
}
Commit	Line	Data
ec26815a	1	/* AFS volume management
1da177e4	2	*
08e0e7c8	3	* Copyright (C) 2002, 2007 Red Hat, Inc. All Rights Reserved.
1da177e4 LT	4	* Written by David Howells ([email protected])
	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	*/
	11
	12	#include <linux/kernel.h>
1da177e4	13	#include <linux/slab.h>
1da177e4 LT	14	#include "internal.h"
1da177e4 LT	15
d2ddc776 DH	16	unsigned __read_mostly afs_volume_gc_delay = 10;
	17	unsigned __read_mostly afs_volume_record_life = 60 * 60;
	18
	19	static const char *const afs_voltypes[] = { "R/W", "R/O", "BAK" };
1da177e4	20
1da177e4	21	/*
d2ddc776 DH	22	* Allocate a volume record and load it up from a vldb record.
	23	*/
	24	static struct afs_volume afs_alloc_volume(struct afs_mount_params params,
	25	struct afs_vldb_entry *vldb,
	26	unsigned long type_mask)
	27	{
	28	struct afs_server_list *slist;
d2ddc776	29	struct afs_volume *volume;
45df8462	30	int ret = -ENOMEM, nr_servers = 0, i;
d2ddc776 DH	31
	32	for (i = 0; i < vldb->nr_servers; i++)
	33	if (vldb->fs_mask[i] & type_mask)
	34	nr_servers++;
	35
	36	volume = kzalloc(sizeof(struct afs_volume), GFP_KERNEL);
	37	if (!volume)
	38	goto error_0;
	39
	40	volume->vid = vldb->vid[params->type];
	41	volume->update_at = ktime_get_real_seconds() + afs_volume_record_life;
	42	volume->cell = afs_get_cell(params->cell);
	43	volume->type = params->type;
	44	volume->type_force = params->force;
	45	volume->name_len = vldb->name_len;
	46
	47	atomic_set(&volume->usage, 1);
	48	INIT_LIST_HEAD(&volume->proc_link);
	49	rwlock_init(&volume->servers_lock);
	50	memcpy(volume->name, vldb->name, vldb->name_len + 1);
	51
	52	slist = afs_alloc_server_list(params->cell, params->key, vldb, type_mask);
	53	if (IS_ERR(slist)) {
	54	ret = PTR_ERR(slist);
	55	goto error_1;
	56	}
	57
	58	refcount_set(&slist->usage, 1);
	59	volume->servers = slist;
d2ddc776 DH	60	return volume;
d2ddc776 DH	61
d2ddc776	62	error_1:
e4415015	63	afs_put_cell(params->net, volume->cell);
d2ddc776 DH	64	kfree(volume);
	65	error_0:
	66	return ERR_PTR(ret);
	67	}
	68
	69	/*
	70	* Look up a VLDB record for a volume.
	71	*/
	72	static struct afs_vldb_entry afs_vl_lookup_vldb(struct afs_cell cell,
	73	struct key *key,
	74	const char *volname,
	75	size_t volnamesz)
	76	{
	77	struct afs_addr_cursor ac;
	78	struct afs_vldb_entry *vldb;
	79	int ret;
	80
	81	ret = afs_set_vl_cursor(&ac, cell);
	82	if (ret < 0)
	83	return ERR_PTR(ret);
	84
	85	while (afs_iterate_addresses(&ac)) {
bf99a53c DH	86	if (!test_bit(ac.index, &ac.alist->probed)) {
	87	ret = afs_vl_get_capabilities(cell->net, &ac, key);
	88	switch (ret) {
	89	case VL_SERVICE:
	90	clear_bit(ac.index, &ac.alist->yfs);
	91	set_bit(ac.index, &ac.alist->probed);
	92	ac.addr->srx_service = ret;
	93	break;
	94	case YFS_VL_SERVICE:
	95	set_bit(ac.index, &ac.alist->yfs);
	96	set_bit(ac.index, &ac.alist->probed);
	97	ac.addr->srx_service = ret;
	98	break;
	99	}
	100	}
	101
d2ddc776 DH	102	vldb = afs_vl_get_entry_by_name_u(cell->net, &ac, key,
	103	volname, volnamesz);
	104	switch (ac.error) {
	105	case 0:
	106	afs_end_cursor(&ac);
	107	return vldb;
	108	case -ECONNABORTED:
	109	ac.error = afs_abort_to_error(ac.abort_code);
	110	goto error;
	111	case -ENOMEM:
	112	case -ENONET:
	113	goto error;
	114	case -ENETUNREACH:
	115	case -EHOSTUNREACH:
	116	case -ECONNREFUSED:
	117	break;
	118	default:
	119	ac.error = -EIO;
	120	goto error;
	121	}
	122	}
	123
	124	error:
	125	return ERR_PTR(afs_end_cursor(&ac));
	126	}
	127
	128	/*
	129	* Look up a volume in the VL server and create a candidate volume record for
	130	* it.
	131	*
	132	* The volume name can be one of the following:
1da177e4 LT	133	* "%[cell:]volume[.]" R/W volume
	134	* "#[cell:]volume[.]" R/O or R/W volume (rwparent=0),
	135	* or R/W (rwparent=1) volume
	136	* "%[cell:]volume.readonly" R/O volume
	137	* "#[cell:]volume.readonly" R/O volume
	138	* "%[cell:]volume.backup" Backup volume
	139	* "#[cell:]volume.backup" Backup volume
	140	*
	141	* The cell name is optional, and defaults to the current cell.
	142	*
	143	* See "The Rules of Mount Point Traversal" in Chapter 5 of the AFS SysAdmin
	144	* Guide
	145	* - Rule 1: Explicit type suffix forces access of that type or nothing
	146	* (no suffix, then use Rule 2 & 3)
	147	* - Rule 2: If parent volume is R/O, then mount R/O volume by preference, R/W
	148	* if not available
	149	* - Rule 3: If parent volume is R/W, then only mount R/W volume unless
	150	* explicitly told otherwise
	151	*/
d2ddc776	152	struct afs_volume afs_create_volume(struct afs_mount_params params)
1da177e4	153	{
d2ddc776 DH	154	struct afs_vldb_entry *vldb;
	155	struct afs_volume *volume;
	156	unsigned long type_mask = 1UL << params->type;
1da177e4	157
d2ddc776 DH	158	vldb = afs_vl_lookup_vldb(params->cell, params->key,
	159	params->volname, params->volnamesz);
	160	if (IS_ERR(vldb))
	161	return ERR_CAST(vldb);
1da177e4	162
d2ddc776 DH	163	if (test_bit(AFS_VLDB_QUERY_ERROR, &vldb->flags)) {
	164	volume = ERR_PTR(vldb->error);
	165	goto error;
	166	}
1da177e4	167
d2ddc776 DH	168	/* Make the final decision on the type we want */
d2ddc776 DH	169	volume = ERR_PTR(-ENOMEDIUM);
00d3b7a4	170	if (params->force) {
d2ddc776	171	if (!(vldb->flags & type_mask))
1da177e4	172	goto error;
d2ddc776	173	} else if (test_bit(AFS_VLDB_HAS_RO, &vldb->flags)) {
00d3b7a4	174	params->type = AFSVL_ROVOL;
d2ddc776	175	} else if (test_bit(AFS_VLDB_HAS_RW, &vldb->flags)) {
00d3b7a4	176	params->type = AFSVL_RWVOL;
ec26815a	177	} else {
1da177e4 LT	178	goto error;
	179	}
	180
d2ddc776 DH	181	type_mask = 1UL << params->type;
d2ddc776 DH	182	volume = afs_alloc_volume(params, vldb, type_mask);
1da177e4	183
d2ddc776 DH	184	error:
	185	kfree(vldb);
	186	return volume;
	187	}
1da177e4	188
d2ddc776 DH	189	/*
	190	* Destroy a volume record
	191	*/
	192	static void afs_destroy_volume(struct afs_net net, struct afs_volume volume)
	193	{
	194	_enter("%p", volume);
1da177e4	195
d2ddc776 DH	196	#ifdef CONFIG_AFS_FSCACHE
	197	ASSERTCMP(volume->cache, ==, NULL);
	198	#endif
1da177e4	199
d2ddc776 DH	200	afs_put_serverlist(net, volume->servers);
	201	afs_put_cell(net, volume->cell);
	202	kfree(volume);
1da177e4	203
d2ddc776 DH	204	_leave(" [destroyed]");
	205	}
	206
	207	/*
	208	* Drop a reference on a volume record.
	209	*/
	210	void afs_put_volume(struct afs_cell cell, struct afs_volume volume)
	211	{
	212	if (volume) {
	213	_enter("%s", volume->name);
	214
	215	if (atomic_dec_and_test(&volume->usage))
	216	afs_destroy_volume(cell->net, volume);
1da177e4	217	}
d2ddc776	218	}
1da177e4	219
d2ddc776 DH	220	/*
	221	* Activate a volume.
	222	*/
	223	void afs_activate_volume(struct afs_volume *volume)
	224	{
9b3f26c9	225	#ifdef CONFIG_AFS_FSCACHE
ad6a942a	226	volume->cache = fscache_acquire_cookie(volume->cell->cache,
9b3f26c9	227	&afs_volume_cache_index_def,
402cb8dd DH	228	&volume->vid, sizeof(volume->vid),
402cb8dd DH	229	NULL, 0,
ee1235a9	230	volume, 0, true);
1da177e4	231	#endif
1da177e4	232
d2ddc776 DH	233	write_lock(&volume->cell->proc_lock);
	234	list_add_tail(&volume->proc_link, &volume->cell->proc_volumes);
	235	write_unlock(&volume->cell->proc_lock);
	236	}
1da177e4	237
d2ddc776 DH	238	/*
	239	* Deactivate a volume.
	240	*/
	241	void afs_deactivate_volume(struct afs_volume *volume)
	242	{
	243	_enter("%s", volume->name);
1da177e4	244
d2ddc776 DH	245	write_lock(&volume->cell->proc_lock);
	246	list_del_init(&volume->proc_link);
	247	write_unlock(&volume->cell->proc_lock);
1da177e4	248
d2ddc776	249	#ifdef CONFIG_AFS_FSCACHE
402cb8dd	250	fscache_relinquish_cookie(volume->cache, NULL,
d2ddc776 DH	251	test_bit(AFS_VOLUME_DELETED, &volume->flags));
	252	volume->cache = NULL;
	253	#endif
1da177e4	254
d2ddc776	255	_leave("");
ec26815a	256	}
1da177e4	257
1da177e4	258	/*
d2ddc776	259	* Query the VL service to update the volume status.
1da177e4	260	*/
d2ddc776	261	static int afs_update_volume_status(struct afs_volume volume, struct key key)
1da177e4	262	{
d2ddc776 DH	263	struct afs_server_list new, old, *discard;
	264	struct afs_vldb_entry *vldb;
	265	char idbuf[16];
	266	int ret, idsz;
1da177e4	267
d2ddc776	268	_enter("");
1da177e4	269
d2ddc776 DH	270	/* We look up an ID by passing it as a decimal string in the
	271	* operation's name parameter.
	272	*/
	273	idsz = sprintf(idbuf, "%u", volume->vid);
1da177e4	274
d2ddc776 DH	275	vldb = afs_vl_lookup_vldb(volume->cell, key, idbuf, idsz);
	276	if (IS_ERR(vldb)) {
	277	ret = PTR_ERR(vldb);
	278	goto error;
	279	}
1da177e4	280
d2ddc776 DH	281	/* See if the volume got renamed. */
	282	if (vldb->name_len != volume->name_len \|\|
	283	memcmp(vldb->name, volume->name, vldb->name_len) != 0) {
	284	/* TODO: Use RCU'd string. */
	285	memcpy(volume->name, vldb->name, AFS_MAXVOLNAME);
	286	volume->name_len = vldb->name_len;
	287	}
	288
	289	/* See if the volume's server list got updated. */
	290	new = afs_alloc_server_list(volume->cell, key,
45df8462	291	vldb, (1 << volume->type));
d2ddc776 DH	292	if (IS_ERR(new)) {
	293	ret = PTR_ERR(new);
	294	goto error_vldb;
	295	}
1da177e4	296
d2ddc776	297	write_lock(&volume->servers_lock);
1da177e4	298
d2ddc776 DH	299	discard = new;
	300	old = volume->servers;
	301	if (afs_annotate_server_list(new, old)) {
	302	new->seq = volume->servers_seq + 1;
	303	volume->servers = new;
	304	smp_wmb();
	305	volume->servers_seq++;
	306	discard = old;
1da177e4 LT	307	}
1da177e4 LT	308
d2ddc776 DH	309	volume->update_at = ktime_get_real_seconds() + afs_volume_record_life;
	310	clear_bit(AFS_VOLUME_NEEDS_UPDATE, &volume->flags);
	311	write_unlock(&volume->servers_lock);
	312	ret = 0;
1da177e4	313
d2ddc776 DH	314	afs_put_serverlist(volume->cell->net, discard);
	315	error_vldb:
	316	kfree(vldb);
	317	error:
	318	_leave(" = %d", ret);
	319	return ret;
	320	}
1da177e4	321
d2ddc776 DH	322	/*
	323	* Make sure the volume record is up to date.
	324	*/
	325	int afs_check_volume_status(struct afs_volume volume, struct key key)
	326	{
	327	time64_t now = ktime_get_real_seconds();
	328	int ret, retries = 0;
1da177e4	329
d2ddc776 DH	330	_enter("");
	331
	332	if (volume->update_at <= now)
	333	set_bit(AFS_VOLUME_NEEDS_UPDATE, &volume->flags);
	334
	335	retry:
	336	if (!test_bit(AFS_VOLUME_NEEDS_UPDATE, &volume->flags) &&
	337	!test_bit(AFS_VOLUME_WAIT, &volume->flags)) {
	338	_leave(" = 0");
	339	return 0;
c435ee34	340	}
1da177e4	341
d2ddc776 DH	342	if (!test_and_set_bit_lock(AFS_VOLUME_UPDATING, &volume->flags)) {
	343	ret = afs_update_volume_status(volume, key);
	344	clear_bit_unlock(AFS_VOLUME_WAIT, &volume->flags);
	345	clear_bit_unlock(AFS_VOLUME_UPDATING, &volume->flags);
	346	wake_up_bit(&volume->flags, AFS_VOLUME_WAIT);
	347	_leave(" = %d", ret);
	348	return ret;
	349	}
1da177e4	350
d2ddc776 DH	351	if (!test_bit(AFS_VOLUME_WAIT, &volume->flags)) {
	352	_leave(" = 0 [no wait]");
	353	return 0;
	354	}
	355
	356	ret = wait_on_bit(&volume->flags, AFS_VOLUME_WAIT, TASK_INTERRUPTIBLE);
	357	if (ret == -ERESTARTSYS) {
	358	_leave(" = %d", ret);
	359	return ret;
	360	}
	361
	362	retries++;
	363	if (retries == 4) {
	364	_leave(" = -ESTALE");
	365	return -ESTALE;
	366	}
	367	goto retry;
ec26815a	368	}