[linux-2.6-block.git] / fs / afs / volume.c

// SPDX-License-Identifier: GPL-2.0-or-later
/* AFS volume management
 *
 * Copyright (C) 2002, 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 */

#include <linux/kernel.h>
#include <linux/slab.h>
#include "internal.h"

static unsigned __read_mostly afs_volume_record_life = 60 * 60;

static void afs_destroy_volume(struct work_struct *work);

/*
 * Insert a volume into a cell.  If there's an existing volume record, that is
 * returned instead with a ref held.
 */
static struct afs_volume *afs_insert_volume_into_cell(struct afs_cell *cell,
						      struct afs_volume *volume)
{
	struct afs_volume *p;
	struct rb_node *parent = NULL, **pp;

	write_seqlock(&cell->volume_lock);

	pp = &cell->volumes.rb_node;
	while (*pp) {
		parent = *pp;
		p = rb_entry(parent, struct afs_volume, cell_node);
		if (p->vid < volume->vid) {
			pp = &(*pp)->rb_left;
		} else if (p->vid > volume->vid) {
			pp = &(*pp)->rb_right;
		} else {
			if (afs_try_get_volume(p, afs_volume_trace_get_cell_insert)) {
				volume = p;
				goto found;
			}

			set_bit(AFS_VOLUME_RM_TREE, &volume->flags);
			rb_replace_node_rcu(&p->cell_node, &volume->cell_node, &cell->volumes);
		}
	}

	rb_link_node_rcu(&volume->cell_node, parent, pp);
	rb_insert_color(&volume->cell_node, &cell->volumes);
	hlist_add_head_rcu(&volume->proc_link, &cell->proc_volumes);

found:
	write_sequnlock(&cell->volume_lock);
	return volume;

}

static void afs_remove_volume_from_cell(struct afs_volume *volume)
{
	struct afs_cell *cell = volume->cell;

	if (!hlist_unhashed(&volume->proc_link)) {
		trace_afs_volume(volume->vid, refcount_read(&cell->ref),
				 afs_volume_trace_remove);
		write_seqlock(&cell->volume_lock);
		hlist_del_rcu(&volume->proc_link);
		if (!test_and_set_bit(AFS_VOLUME_RM_TREE, &volume->flags))
			rb_erase(&volume->cell_node, &cell->volumes);
		write_sequnlock(&cell->volume_lock);
	}
}

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

	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, afs_cell_trace_get_vol);
	volume->type		= params->type;
	volume->type_force	= params->force;
	volume->name_len	= vldb->name_len;
	volume->creation_time	= TIME64_MIN;
	volume->update_time	= TIME64_MIN;

	refcount_set(&volume->ref, 1);
	INIT_HLIST_NODE(&volume->proc_link);
	INIT_WORK(&volume->destructor, afs_destroy_volume);
	rwlock_init(&volume->servers_lock);
	mutex_init(&volume->volsync_lock);
	mutex_init(&volume->cb_check_lock);
	rwlock_init(&volume->cb_v_break_lock);
	INIT_LIST_HEAD(&volume->open_mmaps);
	init_rwsem(&volume->open_mmaps_lock);
	memcpy(volume->name, vldb->name, vldb->name_len + 1);

	for (i = 0; i < AFS_MAXTYPES; i++)
		volume->vids[i] = vldb->vid[i];

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

	*_slist = slist;
	rcu_assign_pointer(volume->servers, slist);
	trace_afs_volume(volume->vid, 1, afs_volume_trace_alloc);
	return volume;

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

/*
 * Look up or allocate a volume record.
 */
static struct afs_volume *afs_lookup_volume(struct afs_fs_context *params,
					    struct afs_vldb_entry *vldb)
{
	struct afs_server_list *slist;
	struct afs_volume *candidate, *volume;

	candidate = afs_alloc_volume(params, vldb, &slist);
	if (IS_ERR(candidate))
		return candidate;

	volume = afs_insert_volume_into_cell(params->cell, candidate);
	if (volume == candidate)
		afs_attach_volume_to_servers(volume, slist);
	else
		afs_put_volume(candidate, afs_volume_trace_put_cell_dup);
	return volume;
}

/*
 * 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_vldb_entry *vldb = ERR_PTR(-EDESTADDRREQ);
	struct afs_vl_cursor vc;
	int ret;

	if (!afs_begin_vlserver_operation(&vc, cell, key))
		return ERR_PTR(-ERESTARTSYS);

	while (afs_select_vlserver(&vc)) {
		vldb = afs_vl_get_entry_by_name_u(&vc, volname, volnamesz);
	}

	ret = afs_end_vlserver_operation(&vc);
	return ret < 0 ? ERR_PTR(ret) : vldb;
}

/*
 * 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_fs_context *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;
	}

	volume = afs_lookup_volume(params, vldb);

error:
	kfree(vldb);
	return volume;
}

/*
 * Destroy a volume record
 */
static void afs_destroy_volume(struct work_struct *work)
{
	struct afs_volume *volume = container_of(work, struct afs_volume, destructor);
	struct afs_server_list *slist = rcu_access_pointer(volume->servers);

	_enter("%p", volume);

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

	afs_detach_volume_from_servers(volume, slist);
	afs_remove_volume_from_cell(volume);
	afs_put_serverlist(volume->cell->net, slist);
	afs_put_cell(volume->cell, afs_cell_trace_put_vol);
	trace_afs_volume(volume->vid, refcount_read(&volume->ref),
			 afs_volume_trace_free);
	kfree_rcu(volume, rcu);

	_leave(" [destroyed]");
}

/*
 * Try to get a reference on a volume record.
 */
bool afs_try_get_volume(struct afs_volume *volume, enum afs_volume_trace reason)
{
	int r;

	if (__refcount_inc_not_zero(&volume->ref, &r)) {
		trace_afs_volume(volume->vid, r + 1, reason);
		return true;
	}
	return false;
}

/*
 * Get a reference on a volume record.
 */
struct afs_volume *afs_get_volume(struct afs_volume *volume,
				  enum afs_volume_trace reason)
{
	if (volume) {
		int r;

		__refcount_inc(&volume->ref, &r);
		trace_afs_volume(volume->vid, r + 1, reason);
	}
	return volume;
}


/*
 * Drop a reference on a volume record.
 */
void afs_put_volume(struct afs_volume *volume, enum afs_volume_trace reason)
{
	if (volume) {
		afs_volid_t vid = volume->vid;
		bool zero;
		int r;

		zero = __refcount_dec_and_test(&volume->ref, &r);
		trace_afs_volume(vid, r - 1, reason);
		if (zero)
			schedule_work(&volume->destructor);
	}
}

/*
 * Activate a volume.
 */
int afs_activate_volume(struct afs_volume *volume)
{
#ifdef CONFIG_AFS_FSCACHE
	struct fscache_volume *vcookie;
	char *name;

	name = kasprintf(GFP_KERNEL, "afs,%s,%llx",
			 volume->cell->name, volume->vid);
	if (!name)
		return -ENOMEM;

	vcookie = fscache_acquire_volume(name, NULL, NULL, 0);
	if (IS_ERR(vcookie)) {
		if (vcookie != ERR_PTR(-EBUSY)) {
			kfree(name);
			return PTR_ERR(vcookie);
		}
		pr_err("AFS: Cache volume key already in use (%s)\n", name);
		vcookie = NULL;
	}
	volume->cache = vcookie;
	kfree(name);
#endif
	return 0;
}

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

#ifdef CONFIG_AFS_FSCACHE
	fscache_relinquish_volume(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[24];
	int ret, idsz;

	_enter("");

	/* We look up an ID by passing it as a decimal string in the
	 * operation's name parameter.
	 */
	idsz = snprintf(idbuf, sizeof(idbuf), "%llu", 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, key, vldb);
	if (IS_ERR(new)) {
		ret = PTR_ERR(new);
		goto error_vldb;
	}

	write_lock(&volume->servers_lock);

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

	/* Check more often if replication is ongoing. */
	if (new->ro_replicating)
		volume->update_at = ktime_get_real_seconds() + 10 * 60;
	else
		volume->update_at = ktime_get_real_seconds() + afs_volume_record_life;
	write_unlock(&volume->servers_lock);

	if (discard == old)
		afs_reattach_volume_to_servers(volume, new, old);
	afs_put_serverlist(volume->cell->net, discard);
	ret = 0;
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 afs_operation *op)
{
	int ret, retries = 0;

	_enter("");

retry:
	if (test_bit(AFS_VOLUME_WAIT, &volume->flags))
		goto wait;
	if (volume->update_at <= ktime_get_real_seconds() ||
	    test_bit(AFS_VOLUME_NEEDS_UPDATE, &volume->flags))
		goto update;
	_leave(" = 0");
	return 0;

update:
	if (!test_and_set_bit_lock(AFS_VOLUME_UPDATING, &volume->flags)) {
		clear_bit(AFS_VOLUME_NEEDS_UPDATE, &volume->flags);
		ret = afs_update_volume_status(volume, op->key);
		if (ret < 0)
			set_bit(AFS_VOLUME_NEEDS_UPDATE, &volume->flags);
		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;
	}

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

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

	retries++;
	if (retries == 4) {
		_leave(" = -ESTALE");
		return -ESTALE;
	}
	goto retry;
}
Commit	Line	Data
2874c5fd	1	// SPDX-License-Identifier: GPL-2.0-or-later
ec26815a	2	/* AFS volume management
1da177e4	3	*
08e0e7c8	4	* Copyright (C) 2002, 2007 Red Hat, Inc. All Rights Reserved.
1da177e4	5	* Written by David Howells (dhowells@redhat.com)
1da177e4 LT	6	*/
	7
	8	#include <linux/kernel.h>
1da177e4	9	#include <linux/slab.h>
1da177e4 LT	10	#include "internal.h"
1da177e4 LT	11
102d8410	12	static unsigned __read_mostly afs_volume_record_life = 60 * 60;
d2ddc776	13
445f9b69 DH	14	static void afs_destroy_volume(struct work_struct *work);
445f9b69 DH	15
20325960 DH	16	/*
	17	* Insert a volume into a cell. If there's an existing volume record, that is
	18	* returned instead with a ref held.
	19	*/
	20	static struct afs_volume afs_insert_volume_into_cell(struct afs_cell cell,
	21	struct afs_volume *volume)
	22	{
	23	struct afs_volume *p;
	24	struct rb_node parent = NULL, *pp;
	25
	26	write_seqlock(&cell->volume_lock);
	27
	28	pp = &cell->volumes.rb_node;
	29	while (*pp) {
	30	parent = *pp;
	31	p = rb_entry(parent, struct afs_volume, cell_node);
	32	if (p->vid < volume->vid) {
	33	pp = &(*pp)->rb_left;
	34	} else if (p->vid > volume->vid) {
	35	pp = &(*pp)->rb_right;
	36	} else {
9a6b294a DH	37	if (afs_try_get_volume(p, afs_volume_trace_get_cell_insert)) {
	38	volume = p;
	39	goto found;
	40	}
	41
	42	set_bit(AFS_VOLUME_RM_TREE, &volume->flags);
	43	rb_replace_node_rcu(&p->cell_node, &volume->cell_node, &cell->volumes);
20325960 DH	44	}
	45	}
	46
	47	rb_link_node_rcu(&volume->cell_node, parent, pp);
	48	rb_insert_color(&volume->cell_node, &cell->volumes);
	49	hlist_add_head_rcu(&volume->proc_link, &cell->proc_volumes);
	50
	51	found:
	52	write_sequnlock(&cell->volume_lock);
	53	return volume;
	54
	55	}
	56
	57	static void afs_remove_volume_from_cell(struct afs_volume *volume)
	58	{
	59	struct afs_cell *cell = volume->cell;
	60
	61	if (!hlist_unhashed(&volume->proc_link)) {
c56f9ec8	62	trace_afs_volume(volume->vid, refcount_read(&cell->ref),
20325960 DH	63	afs_volume_trace_remove);
	64	write_seqlock(&cell->volume_lock);
	65	hlist_del_rcu(&volume->proc_link);
9a6b294a DH	66	if (!test_and_set_bit(AFS_VOLUME_RM_TREE, &volume->flags))
9a6b294a DH	67	rb_erase(&volume->cell_node, &cell->volumes);
20325960 DH	68	write_sequnlock(&cell->volume_lock);
	69	}
	70	}
	71
1da177e4	72	/*
d2ddc776 DH	73	* Allocate a volume record and load it up from a vldb record.
d2ddc776 DH	74	*/
13fcc683	75	static struct afs_volume afs_alloc_volume(struct afs_fs_context params,
d2ddc776	76	struct afs_vldb_entry *vldb,
ca0e79a4	77	struct afs_server_list **_slist)
d2ddc776 DH	78	{
d2ddc776 DH	79	struct afs_server_list *slist;
d2ddc776	80	struct afs_volume *volume;
ca0e79a4	81	int ret = -ENOMEM, i;
d2ddc776 DH	82
	83	volume = kzalloc(sizeof(struct afs_volume), GFP_KERNEL);
	84	if (!volume)
	85	goto error_0;
	86
	87	volume->vid = vldb->vid[params->type];
	88	volume->update_at = ktime_get_real_seconds() + afs_volume_record_life;
dca54a7b	89	volume->cell = afs_get_cell(params->cell, afs_cell_trace_get_vol);
d2ddc776 DH	90	volume->type = params->type;
	91	volume->type_force = params->force;
	92	volume->name_len = vldb->name_len;
16069e13 DH	93	volume->creation_time = TIME64_MIN;
16069e13 DH	94	volume->update_time = TIME64_MIN;
d2ddc776	95
c56f9ec8	96	refcount_set(&volume->ref, 1);
20325960	97	INIT_HLIST_NODE(&volume->proc_link);
445f9b69	98	INIT_WORK(&volume->destructor, afs_destroy_volume);
d2ddc776	99	rwlock_init(&volume->servers_lock);
16069e13	100	mutex_init(&volume->volsync_lock);
453924de	101	mutex_init(&volume->cb_check_lock);
90fa9b64	102	rwlock_init(&volume->cb_v_break_lock);
453924de DH	103	INIT_LIST_HEAD(&volume->open_mmaps);
453924de DH	104	init_rwsem(&volume->open_mmaps_lock);
d2ddc776 DH	105	memcpy(volume->name, vldb->name, vldb->name_len + 1);
d2ddc776 DH	106
ca0e79a4 DH	107	for (i = 0; i < AFS_MAXTYPES; i++)
	108	volume->vids[i] = vldb->vid[i];
	109
	110	slist = afs_alloc_server_list(volume, params->key, vldb);
d2ddc776 DH	111	if (IS_ERR(slist)) {
	112	ret = PTR_ERR(slist);
	113	goto error_1;
	114	}
	115
ca0e79a4	116	*_slist = slist;
8a070a96	117	rcu_assign_pointer(volume->servers, slist);
cca37d45	118	trace_afs_volume(volume->vid, 1, afs_volume_trace_alloc);
d2ddc776 DH	119	return volume;
d2ddc776 DH	120
d2ddc776	121	error_1:
dca54a7b	122	afs_put_cell(volume->cell, afs_cell_trace_put_vol);
d2ddc776 DH	123	kfree(volume);
	124	error_0:
	125	return ERR_PTR(ret);
	126	}
	127
20325960 DH	128	/*
	129	* Look up or allocate a volume record.
	130	*/
	131	static struct afs_volume afs_lookup_volume(struct afs_fs_context params,
ca0e79a4	132	struct afs_vldb_entry *vldb)
20325960	133	{
ca0e79a4	134	struct afs_server_list *slist;
20325960 DH	135	struct afs_volume candidate, volume;
20325960 DH	136
ca0e79a4	137	candidate = afs_alloc_volume(params, vldb, &slist);
20325960 DH	138	if (IS_ERR(candidate))
	139	return candidate;
	140
	141	volume = afs_insert_volume_into_cell(params->cell, candidate);
ca0e79a4 DH	142	if (volume == candidate)
	143	afs_attach_volume_to_servers(volume, slist);
	144	else
445f9b69	145	afs_put_volume(candidate, afs_volume_trace_put_cell_dup);
20325960 DH	146	return volume;
	147	}
	148
d2ddc776 DH	149	/*
	150	* Look up a VLDB record for a volume.
	151	*/
	152	static struct afs_vldb_entry afs_vl_lookup_vldb(struct afs_cell cell,
	153	struct key *key,
	154	const char *volname,
	155	size_t volnamesz)
	156	{
0a5143f2 DH	157	struct afs_vldb_entry *vldb = ERR_PTR(-EDESTADDRREQ);
0a5143f2 DH	158	struct afs_vl_cursor vc;
d2ddc776 DH	159	int ret;
d2ddc776 DH	160
0a5143f2 DH	161	if (!afs_begin_vlserver_operation(&vc, cell, key))
0a5143f2 DH	162	return ERR_PTR(-ERESTARTSYS);
d2ddc776	163
0a5143f2	164	while (afs_select_vlserver(&vc)) {
0a5143f2	165	vldb = afs_vl_get_entry_by_name_u(&vc, volname, volnamesz);
d2ddc776 DH	166	}
d2ddc776 DH	167
0a5143f2 DH	168	ret = afs_end_vlserver_operation(&vc);
0a5143f2 DH	169	return ret < 0 ? ERR_PTR(ret) : vldb;
d2ddc776 DH	170	}
	171
	172	/*
	173	* Look up a volume in the VL server and create a candidate volume record for
	174	* it.
	175	*
	176	* The volume name can be one of the following:
1da177e4 LT	177	* "%[cell:]volume[.]" R/W volume
	178	* "#[cell:]volume[.]" R/O or R/W volume (rwparent=0),
	179	* or R/W (rwparent=1) volume
	180	* "%[cell:]volume.readonly" R/O volume
	181	* "#[cell:]volume.readonly" R/O volume
	182	* "%[cell:]volume.backup" Backup volume
	183	* "#[cell:]volume.backup" Backup volume
	184	*
	185	* The cell name is optional, and defaults to the current cell.
	186	*
	187	* See "The Rules of Mount Point Traversal" in Chapter 5 of the AFS SysAdmin
	188	* Guide
	189	* - Rule 1: Explicit type suffix forces access of that type or nothing
	190	* (no suffix, then use Rule 2 & 3)
	191	* - Rule 2: If parent volume is R/O, then mount R/O volume by preference, R/W
	192	* if not available
	193	* - Rule 3: If parent volume is R/W, then only mount R/W volume unless
	194	* explicitly told otherwise
	195	*/
13fcc683	196	struct afs_volume afs_create_volume(struct afs_fs_context params)
1da177e4	197	{
d2ddc776 DH	198	struct afs_vldb_entry *vldb;
	199	struct afs_volume *volume;
	200	unsigned long type_mask = 1UL << params->type;
1da177e4	201
d2ddc776 DH	202	vldb = afs_vl_lookup_vldb(params->cell, params->key,
	203	params->volname, params->volnamesz);
	204	if (IS_ERR(vldb))
	205	return ERR_CAST(vldb);
1da177e4	206
d2ddc776 DH	207	if (test_bit(AFS_VLDB_QUERY_ERROR, &vldb->flags)) {
	208	volume = ERR_PTR(vldb->error);
	209	goto error;
	210	}
1da177e4	211
d2ddc776 DH	212	/* Make the final decision on the type we want */
d2ddc776 DH	213	volume = ERR_PTR(-ENOMEDIUM);
00d3b7a4	214	if (params->force) {
d2ddc776	215	if (!(vldb->flags & type_mask))
1da177e4	216	goto error;
d2ddc776	217	} else if (test_bit(AFS_VLDB_HAS_RO, &vldb->flags)) {
00d3b7a4	218	params->type = AFSVL_ROVOL;
d2ddc776	219	} else if (test_bit(AFS_VLDB_HAS_RW, &vldb->flags)) {
00d3b7a4	220	params->type = AFSVL_RWVOL;
ec26815a	221	} else {
1da177e4 LT	222	goto error;
	223	}
	224
ca0e79a4	225	volume = afs_lookup_volume(params, vldb);
1da177e4	226
d2ddc776 DH	227	error:
	228	kfree(vldb);
	229	return volume;
	230	}
1da177e4	231
d2ddc776 DH	232	/*
	233	* Destroy a volume record
	234	*/
445f9b69	235	static void afs_destroy_volume(struct work_struct *work)
d2ddc776	236	{
445f9b69	237	struct afs_volume *volume = container_of(work, struct afs_volume, destructor);
ca0e79a4 DH	238	struct afs_server_list *slist = rcu_access_pointer(volume->servers);
ca0e79a4 DH	239
d2ddc776	240	_enter("%p", volume);
1da177e4	241
d2ddc776 DH	242	#ifdef CONFIG_AFS_FSCACHE
	243	ASSERTCMP(volume->cache, ==, NULL);
	244	#endif
1da177e4	245
ca0e79a4	246	afs_detach_volume_from_servers(volume, slist);
20325960	247	afs_remove_volume_from_cell(volume);
445f9b69	248	afs_put_serverlist(volume->cell->net, slist);
dca54a7b	249	afs_put_cell(volume->cell, afs_cell_trace_put_vol);
c56f9ec8	250	trace_afs_volume(volume->vid, refcount_read(&volume->ref),
cca37d45	251	afs_volume_trace_free);
20325960	252	kfree_rcu(volume, rcu);
1da177e4	253
d2ddc776 DH	254	_leave(" [destroyed]");
	255	}
	256
9a6b294a DH	257	/*
	258	* Try to get a reference on a volume record.
	259	*/
	260	bool afs_try_get_volume(struct afs_volume *volume, enum afs_volume_trace reason)
	261	{
	262	int r;
	263
	264	if (__refcount_inc_not_zero(&volume->ref, &r)) {
	265	trace_afs_volume(volume->vid, r + 1, reason);
	266	return true;
	267	}
	268	return false;
	269	}
	270
d2ddc776	271	/*
cca37d45	272	* Get a reference on a volume record.
d2ddc776	273	*/
cca37d45 DH	274	struct afs_volume afs_get_volume(struct afs_volume volume,
cca37d45 DH	275	enum afs_volume_trace reason)
d2ddc776 DH	276	{
d2ddc776 DH	277	if (volume) {
c56f9ec8 DH	278	int r;
	279
	280	__refcount_inc(&volume->ref, &r);
	281	trace_afs_volume(volume->vid, r + 1, reason);
cca37d45 DH	282	}
	283	return volume;
	284	}
	285
d2ddc776	286
cca37d45 DH	287	/*
	288	* Drop a reference on a volume record.
	289	*/
445f9b69	290	void afs_put_volume(struct afs_volume *volume, enum afs_volume_trace reason)
cca37d45 DH	291	{
	292	if (volume) {
	293	afs_volid_t vid = volume->vid;
c56f9ec8 DH	294	bool zero;
	295	int r;
	296
	297	zero = __refcount_dec_and_test(&volume->ref, &r);
	298	trace_afs_volume(vid, r - 1, reason);
	299	if (zero)
445f9b69	300	schedule_work(&volume->destructor);
1da177e4	301	}
d2ddc776	302	}
1da177e4	303
d2ddc776 DH	304	/*
	305	* Activate a volume.
	306	*/
523d27cd	307	int afs_activate_volume(struct afs_volume *volume)
d2ddc776	308	{
9b3f26c9	309	#ifdef CONFIG_AFS_FSCACHE
523d27cd DH	310	struct fscache_volume *vcookie;
	311	char *name;
	312
	313	name = kasprintf(GFP_KERNEL, "afs,%s,%llx",
	314	volume->cell->name, volume->vid);
	315	if (!name)
	316	return -ENOMEM;
	317
	318	vcookie = fscache_acquire_volume(name, NULL, NULL, 0);
	319	if (IS_ERR(vcookie)) {
	320	if (vcookie != ERR_PTR(-EBUSY)) {
	321	kfree(name);
	322	return PTR_ERR(vcookie);
	323	}
	324	pr_err("AFS: Cache volume key already in use (%s)\n", name);
	325	vcookie = NULL;
	326	}
	327	volume->cache = vcookie;
	328	kfree(name);
1da177e4	329	#endif
523d27cd	330	return 0;
d2ddc776	331	}
1da177e4	332
d2ddc776 DH	333	/*
	334	* Deactivate a volume.
	335	*/
	336	void afs_deactivate_volume(struct afs_volume *volume)
	337	{
	338	_enter("%s", volume->name);
1da177e4	339
d2ddc776	340	#ifdef CONFIG_AFS_FSCACHE
523d27cd	341	fscache_relinquish_volume(volume->cache, NULL,
d2ddc776 DH	342	test_bit(AFS_VOLUME_DELETED, &volume->flags));
	343	volume->cache = NULL;
	344	#endif
1da177e4	345
d2ddc776	346	_leave("");
ec26815a	347	}
1da177e4	348
1da177e4	349	/*
d2ddc776	350	* Query the VL service to update the volume status.
1da177e4	351	*/
d2ddc776	352	static int afs_update_volume_status(struct afs_volume volume, struct key key)
1da177e4	353	{
d2ddc776 DH	354	struct afs_server_list new, old, *discard;
d2ddc776 DH	355	struct afs_vldb_entry *vldb;
6ea38e2a	356	char idbuf[24];
d2ddc776	357	int ret, idsz;
1da177e4	358
d2ddc776	359	_enter("");
1da177e4	360
d2ddc776 DH	361	/* We look up an ID by passing it as a decimal string in the
	362	* operation's name parameter.
	363	*/
6ea38e2a	364	idsz = snprintf(idbuf, sizeof(idbuf), "%llu", volume->vid);
1da177e4	365
d2ddc776 DH	366	vldb = afs_vl_lookup_vldb(volume->cell, key, idbuf, idsz);
	367	if (IS_ERR(vldb)) {
	368	ret = PTR_ERR(vldb);
	369	goto error;
	370	}
1da177e4	371
d2ddc776 DH	372	/* See if the volume got renamed. */
	373	if (vldb->name_len != volume->name_len \|\|
	374	memcmp(vldb->name, volume->name, vldb->name_len) != 0) {
	375	/* TODO: Use RCU'd string. */
	376	memcpy(volume->name, vldb->name, AFS_MAXVOLNAME);
	377	volume->name_len = vldb->name_len;
	378	}
	379
	380	/* See if the volume's server list got updated. */
ca0e79a4	381	new = afs_alloc_server_list(volume, key, vldb);
d2ddc776 DH	382	if (IS_ERR(new)) {
	383	ret = PTR_ERR(new);
	384	goto error_vldb;
	385	}
1da177e4	386
d2ddc776	387	write_lock(&volume->servers_lock);
1da177e4	388
d2ddc776	389	discard = new;
8a070a96 DH	390	old = rcu_dereference_protected(volume->servers,
8a070a96 DH	391	lockdep_is_held(&volume->servers_lock));
d2ddc776 DH	392	if (afs_annotate_server_list(new, old)) {
d2ddc776 DH	393	new->seq = volume->servers_seq + 1;
8a070a96	394	rcu_assign_pointer(volume->servers, new);
d2ddc776 DH	395	smp_wmb();
	396	volume->servers_seq++;
	397	discard = old;
1da177e4 LT	398	}
1da177e4 LT	399
495f2ae9 DH	400	/* Check more often if replication is ongoing. */
	401	if (new->ro_replicating)
	402	volume->update_at = ktime_get_real_seconds() + 10 * 60;
	403	else
	404	volume->update_at = ktime_get_real_seconds() + afs_volume_record_life;
d2ddc776	405	write_unlock(&volume->servers_lock);
1da177e4	406
ca0e79a4 DH	407	if (discard == old)
ca0e79a4 DH	408	afs_reattach_volume_to_servers(volume, new, old);
d2ddc776	409	afs_put_serverlist(volume->cell->net, discard);
ca0e79a4	410	ret = 0;
d2ddc776 DH	411	error_vldb:
	412	kfree(vldb);
	413	error:
	414	_leave(" = %d", ret);
	415	return ret;
	416	}
1da177e4	417
d2ddc776 DH	418	/*
	419	* Make sure the volume record is up to date.
	420	*/
e49c7b2f	421	int afs_check_volume_status(struct afs_volume volume, struct afs_operation op)
d2ddc776	422	{
d2ddc776	423	int ret, retries = 0;
1da177e4	424
d2ddc776 DH	425	_enter("");
d2ddc776 DH	426
d2ddc776	427	retry:
f6cbb368 DH	428	if (test_bit(AFS_VOLUME_WAIT, &volume->flags))
	429	goto wait;
	430	if (volume->update_at <= ktime_get_real_seconds() \|\|
	431	test_bit(AFS_VOLUME_NEEDS_UPDATE, &volume->flags))
	432	goto update;
	433	_leave(" = 0");
	434	return 0;
	435
	436	update:
d2ddc776	437	if (!test_and_set_bit_lock(AFS_VOLUME_UPDATING, &volume->flags)) {
f6cbb368	438	clear_bit(AFS_VOLUME_NEEDS_UPDATE, &volume->flags);
e49c7b2f	439	ret = afs_update_volume_status(volume, op->key);
f6cbb368 DH	440	if (ret < 0)
f6cbb368 DH	441	set_bit(AFS_VOLUME_NEEDS_UPDATE, &volume->flags);
d2ddc776 DH	442	clear_bit_unlock(AFS_VOLUME_WAIT, &volume->flags);
	443	clear_bit_unlock(AFS_VOLUME_UPDATING, &volume->flags);
	444	wake_up_bit(&volume->flags, AFS_VOLUME_WAIT);
	445	_leave(" = %d", ret);
	446	return ret;
	447	}
1da177e4	448
f6cbb368	449	wait:
d2ddc776 DH	450	if (!test_bit(AFS_VOLUME_WAIT, &volume->flags)) {
	451	_leave(" = 0 [no wait]");
	452	return 0;
	453	}
	454
c4bfda16	455	ret = wait_on_bit(&volume->flags, AFS_VOLUME_WAIT,
e49c7b2f DH	456	(op->flags & AFS_OPERATION_UNINTR) ?
e49c7b2f DH	457	TASK_UNINTERRUPTIBLE : TASK_INTERRUPTIBLE);
d2ddc776 DH	458	if (ret == -ERESTARTSYS) {
	459	_leave(" = %d", ret);
	460	return ret;
	461	}
	462
	463	retries++;
	464	if (retries == 4) {
	465	_leave(" = -ESTALE");
	466	return -ESTALE;
	467	}
	468	goto retry;
ec26815a	469	}