[people/ms/linux.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;

/*
 * 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 {
			volume = afs_get_volume(p, afs_volume_trace_get_cell_insert);
			goto found;
		}
	}

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

	refcount_set(&volume->ref, 1);
	INIT_HLIST_NODE(&volume->proc_link);
	rwlock_init(&volume->servers_lock);
	rwlock_init(&volume->cb_v_break_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);
	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,
					    unsigned long type_mask)
{
	struct afs_volume *candidate, *volume;

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

	volume = afs_insert_volume_into_cell(params->cell, candidate);
	if (volume != candidate)
		afs_put_volume(params->net, 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;
	}

	type_mask = 1UL << params->type;
	volume = afs_lookup_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_remove_volume_from_cell(volume);
	afs_put_serverlist(net, rcu_access_pointer(volume->servers));
	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]");
}

/*
 * 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_net *net, 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)
			afs_destroy_volume(net, volume);
	}
}

/*
 * 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[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, "%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->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 = 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;
	}

	volume->update_at = ktime_get_real_seconds() + afs_volume_record_life;
	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 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
20325960 DH	14	/*
	15	* Insert a volume into a cell. If there's an existing volume record, that is
	16	* returned instead with a ref held.
	17	*/
	18	static struct afs_volume afs_insert_volume_into_cell(struct afs_cell cell,
	19	struct afs_volume *volume)
	20	{
	21	struct afs_volume *p;
	22	struct rb_node parent = NULL, *pp;
	23
	24	write_seqlock(&cell->volume_lock);
	25
	26	pp = &cell->volumes.rb_node;
	27	while (*pp) {
	28	parent = *pp;
	29	p = rb_entry(parent, struct afs_volume, cell_node);
	30	if (p->vid < volume->vid) {
	31	pp = &(*pp)->rb_left;
	32	} else if (p->vid > volume->vid) {
	33	pp = &(*pp)->rb_right;
	34	} else {
	35	volume = afs_get_volume(p, afs_volume_trace_get_cell_insert);
	36	goto found;
	37	}
	38	}
	39
	40	rb_link_node_rcu(&volume->cell_node, parent, pp);
	41	rb_insert_color(&volume->cell_node, &cell->volumes);
	42	hlist_add_head_rcu(&volume->proc_link, &cell->proc_volumes);
	43
	44	found:
	45	write_sequnlock(&cell->volume_lock);
	46	return volume;
	47
	48	}
	49
	50	static void afs_remove_volume_from_cell(struct afs_volume *volume)
	51	{
	52	struct afs_cell *cell = volume->cell;
	53
	54	if (!hlist_unhashed(&volume->proc_link)) {
c56f9ec8	55	trace_afs_volume(volume->vid, refcount_read(&cell->ref),
20325960 DH	56	afs_volume_trace_remove);
	57	write_seqlock(&cell->volume_lock);
	58	hlist_del_rcu(&volume->proc_link);
	59	rb_erase(&volume->cell_node, &cell->volumes);
	60	write_sequnlock(&cell->volume_lock);
	61	}
	62	}
	63
1da177e4	64	/*
d2ddc776 DH	65	* Allocate a volume record and load it up from a vldb record.
d2ddc776 DH	66	*/
13fcc683	67	static struct afs_volume afs_alloc_volume(struct afs_fs_context params,
d2ddc776 DH	68	struct afs_vldb_entry *vldb,
	69	unsigned long type_mask)
	70	{
	71	struct afs_server_list *slist;
d2ddc776	72	struct afs_volume *volume;
45df8462	73	int ret = -ENOMEM, nr_servers = 0, i;
d2ddc776 DH	74
	75	for (i = 0; i < vldb->nr_servers; i++)
	76	if (vldb->fs_mask[i] & type_mask)
	77	nr_servers++;
	78
	79	volume = kzalloc(sizeof(struct afs_volume), GFP_KERNEL);
	80	if (!volume)
	81	goto error_0;
	82
	83	volume->vid = vldb->vid[params->type];
	84	volume->update_at = ktime_get_real_seconds() + afs_volume_record_life;
dca54a7b	85	volume->cell = afs_get_cell(params->cell, afs_cell_trace_get_vol);
d2ddc776 DH	86	volume->type = params->type;
	87	volume->type_force = params->force;
	88	volume->name_len = vldb->name_len;
	89
c56f9ec8	90	refcount_set(&volume->ref, 1);
20325960	91	INIT_HLIST_NODE(&volume->proc_link);
d2ddc776	92	rwlock_init(&volume->servers_lock);
90fa9b64	93	rwlock_init(&volume->cb_v_break_lock);
d2ddc776 DH	94	memcpy(volume->name, vldb->name, vldb->name_len + 1);
	95
	96	slist = afs_alloc_server_list(params->cell, params->key, vldb, type_mask);
	97	if (IS_ERR(slist)) {
	98	ret = PTR_ERR(slist);
	99	goto error_1;
	100	}
	101
	102	refcount_set(&slist->usage, 1);
8a070a96	103	rcu_assign_pointer(volume->servers, slist);
cca37d45	104	trace_afs_volume(volume->vid, 1, afs_volume_trace_alloc);
d2ddc776 DH	105	return volume;
d2ddc776 DH	106
d2ddc776	107	error_1:
dca54a7b	108	afs_put_cell(volume->cell, afs_cell_trace_put_vol);
d2ddc776 DH	109	kfree(volume);
	110	error_0:
	111	return ERR_PTR(ret);
	112	}
	113
20325960 DH	114	/*
	115	* Look up or allocate a volume record.
	116	*/
	117	static struct afs_volume afs_lookup_volume(struct afs_fs_context params,
	118	struct afs_vldb_entry *vldb,
	119	unsigned long type_mask)
	120	{
	121	struct afs_volume candidate, volume;
	122
	123	candidate = afs_alloc_volume(params, vldb, type_mask);
	124	if (IS_ERR(candidate))
	125	return candidate;
	126
	127	volume = afs_insert_volume_into_cell(params->cell, candidate);
	128	if (volume != candidate)
	129	afs_put_volume(params->net, candidate, afs_volume_trace_put_cell_dup);
	130	return volume;
	131	}
	132
d2ddc776 DH	133	/*
	134	* Look up a VLDB record for a volume.
	135	*/
	136	static struct afs_vldb_entry afs_vl_lookup_vldb(struct afs_cell cell,
	137	struct key *key,
	138	const char *volname,
	139	size_t volnamesz)
	140	{
0a5143f2 DH	141	struct afs_vldb_entry *vldb = ERR_PTR(-EDESTADDRREQ);
0a5143f2 DH	142	struct afs_vl_cursor vc;
d2ddc776 DH	143	int ret;
d2ddc776 DH	144
0a5143f2 DH	145	if (!afs_begin_vlserver_operation(&vc, cell, key))
0a5143f2 DH	146	return ERR_PTR(-ERESTARTSYS);
d2ddc776	147
0a5143f2	148	while (afs_select_vlserver(&vc)) {
0a5143f2	149	vldb = afs_vl_get_entry_by_name_u(&vc, volname, volnamesz);
d2ddc776 DH	150	}
d2ddc776 DH	151
0a5143f2 DH	152	ret = afs_end_vlserver_operation(&vc);
0a5143f2 DH	153	return ret < 0 ? ERR_PTR(ret) : vldb;
d2ddc776 DH	154	}
	155
	156	/*
	157	* Look up a volume in the VL server and create a candidate volume record for
	158	* it.
	159	*
	160	* The volume name can be one of the following:
1da177e4 LT	161	* "%[cell:]volume[.]" R/W volume
	162	* "#[cell:]volume[.]" R/O or R/W volume (rwparent=0),
	163	* or R/W (rwparent=1) volume
	164	* "%[cell:]volume.readonly" R/O volume
	165	* "#[cell:]volume.readonly" R/O volume
	166	* "%[cell:]volume.backup" Backup volume
	167	* "#[cell:]volume.backup" Backup volume
	168	*
	169	* The cell name is optional, and defaults to the current cell.
	170	*
	171	* See "The Rules of Mount Point Traversal" in Chapter 5 of the AFS SysAdmin
	172	* Guide
	173	* - Rule 1: Explicit type suffix forces access of that type or nothing
	174	* (no suffix, then use Rule 2 & 3)
	175	* - Rule 2: If parent volume is R/O, then mount R/O volume by preference, R/W
	176	* if not available
	177	* - Rule 3: If parent volume is R/W, then only mount R/W volume unless
	178	* explicitly told otherwise
	179	*/
13fcc683	180	struct afs_volume afs_create_volume(struct afs_fs_context params)
1da177e4	181	{
d2ddc776 DH	182	struct afs_vldb_entry *vldb;
	183	struct afs_volume *volume;
	184	unsigned long type_mask = 1UL << params->type;
1da177e4	185
d2ddc776 DH	186	vldb = afs_vl_lookup_vldb(params->cell, params->key,
	187	params->volname, params->volnamesz);
	188	if (IS_ERR(vldb))
	189	return ERR_CAST(vldb);
1da177e4	190
d2ddc776 DH	191	if (test_bit(AFS_VLDB_QUERY_ERROR, &vldb->flags)) {
	192	volume = ERR_PTR(vldb->error);
	193	goto error;
	194	}
1da177e4	195
d2ddc776 DH	196	/* Make the final decision on the type we want */
d2ddc776 DH	197	volume = ERR_PTR(-ENOMEDIUM);
00d3b7a4	198	if (params->force) {
d2ddc776	199	if (!(vldb->flags & type_mask))
1da177e4	200	goto error;
d2ddc776	201	} else if (test_bit(AFS_VLDB_HAS_RO, &vldb->flags)) {
00d3b7a4	202	params->type = AFSVL_ROVOL;
d2ddc776	203	} else if (test_bit(AFS_VLDB_HAS_RW, &vldb->flags)) {
00d3b7a4	204	params->type = AFSVL_RWVOL;
ec26815a	205	} else {
1da177e4 LT	206	goto error;
	207	}
	208
d2ddc776	209	type_mask = 1UL << params->type;
20325960	210	volume = afs_lookup_volume(params, vldb, type_mask);
1da177e4	211
d2ddc776 DH	212	error:
	213	kfree(vldb);
	214	return volume;
	215	}
1da177e4	216
d2ddc776 DH	217	/*
	218	* Destroy a volume record
	219	*/
	220	static void afs_destroy_volume(struct afs_net net, struct afs_volume volume)
	221	{
	222	_enter("%p", volume);
1da177e4	223
d2ddc776 DH	224	#ifdef CONFIG_AFS_FSCACHE
	225	ASSERTCMP(volume->cache, ==, NULL);
	226	#endif
1da177e4	227
20325960	228	afs_remove_volume_from_cell(volume);
8a070a96	229	afs_put_serverlist(net, rcu_access_pointer(volume->servers));
dca54a7b	230	afs_put_cell(volume->cell, afs_cell_trace_put_vol);
c56f9ec8	231	trace_afs_volume(volume->vid, refcount_read(&volume->ref),
cca37d45	232	afs_volume_trace_free);
20325960	233	kfree_rcu(volume, rcu);
1da177e4	234
d2ddc776 DH	235	_leave(" [destroyed]");
	236	}
	237
	238	/*
cca37d45	239	* Get a reference on a volume record.
d2ddc776	240	*/
cca37d45 DH	241	struct afs_volume afs_get_volume(struct afs_volume volume,
cca37d45 DH	242	enum afs_volume_trace reason)
d2ddc776 DH	243	{
d2ddc776 DH	244	if (volume) {
c56f9ec8 DH	245	int r;
	246
	247	__refcount_inc(&volume->ref, &r);
	248	trace_afs_volume(volume->vid, r + 1, reason);
cca37d45 DH	249	}
	250	return volume;
	251	}
	252
d2ddc776	253
cca37d45 DH	254	/*
	255	* Drop a reference on a volume record.
	256	*/
	257	void afs_put_volume(struct afs_net net, struct afs_volume volume,
	258	enum afs_volume_trace reason)
	259	{
	260	if (volume) {
	261	afs_volid_t vid = volume->vid;
c56f9ec8 DH	262	bool zero;
	263	int r;
	264
	265	zero = __refcount_dec_and_test(&volume->ref, &r);
	266	trace_afs_volume(vid, r - 1, reason);
	267	if (zero)
e49c7b2f	268	afs_destroy_volume(net, volume);
1da177e4	269	}
d2ddc776	270	}
1da177e4	271
d2ddc776 DH	272	/*
	273	* Activate a volume.
	274	*/
523d27cd	275	int afs_activate_volume(struct afs_volume *volume)
d2ddc776	276	{
9b3f26c9	277	#ifdef CONFIG_AFS_FSCACHE
523d27cd DH	278	struct fscache_volume *vcookie;
	279	char *name;
	280
	281	name = kasprintf(GFP_KERNEL, "afs,%s,%llx",
	282	volume->cell->name, volume->vid);
	283	if (!name)
	284	return -ENOMEM;
	285
	286	vcookie = fscache_acquire_volume(name, NULL, NULL, 0);
	287	if (IS_ERR(vcookie)) {
	288	if (vcookie != ERR_PTR(-EBUSY)) {
	289	kfree(name);
	290	return PTR_ERR(vcookie);
	291	}
	292	pr_err("AFS: Cache volume key already in use (%s)\n", name);
	293	vcookie = NULL;
	294	}
	295	volume->cache = vcookie;
	296	kfree(name);
1da177e4	297	#endif
523d27cd	298	return 0;
d2ddc776	299	}
1da177e4	300
d2ddc776 DH	301	/*
	302	* Deactivate a volume.
	303	*/
	304	void afs_deactivate_volume(struct afs_volume *volume)
	305	{
	306	_enter("%s", volume->name);
1da177e4	307
d2ddc776	308	#ifdef CONFIG_AFS_FSCACHE
523d27cd	309	fscache_relinquish_volume(volume->cache, NULL,
d2ddc776 DH	310	test_bit(AFS_VOLUME_DELETED, &volume->flags));
	311	volume->cache = NULL;
	312	#endif
1da177e4	313
d2ddc776	314	_leave("");
ec26815a	315	}
1da177e4	316
1da177e4	317	/*
d2ddc776	318	* Query the VL service to update the volume status.
1da177e4	319	*/
d2ddc776	320	static int afs_update_volume_status(struct afs_volume volume, struct key key)
1da177e4	321	{
d2ddc776 DH	322	struct afs_server_list new, old, *discard;
	323	struct afs_vldb_entry *vldb;
	324	char idbuf[16];
	325	int ret, idsz;
1da177e4	326
d2ddc776	327	_enter("");
1da177e4	328
d2ddc776 DH	329	/* We look up an ID by passing it as a decimal string in the
	330	* operation's name parameter.
	331	*/
3b6492df	332	idsz = sprintf(idbuf, "%llu", volume->vid);
1da177e4	333
d2ddc776 DH	334	vldb = afs_vl_lookup_vldb(volume->cell, key, idbuf, idsz);
	335	if (IS_ERR(vldb)) {
	336	ret = PTR_ERR(vldb);
	337	goto error;
	338	}
1da177e4	339
d2ddc776 DH	340	/* See if the volume got renamed. */
	341	if (vldb->name_len != volume->name_len \|\|
	342	memcmp(vldb->name, volume->name, vldb->name_len) != 0) {
	343	/* TODO: Use RCU'd string. */
	344	memcpy(volume->name, vldb->name, AFS_MAXVOLNAME);
	345	volume->name_len = vldb->name_len;
	346	}
	347
	348	/* See if the volume's server list got updated. */
	349	new = afs_alloc_server_list(volume->cell, key,
45df8462	350	vldb, (1 << volume->type));
d2ddc776 DH	351	if (IS_ERR(new)) {
	352	ret = PTR_ERR(new);
	353	goto error_vldb;
	354	}
1da177e4	355
d2ddc776	356	write_lock(&volume->servers_lock);
1da177e4	357
d2ddc776	358	discard = new;
8a070a96 DH	359	old = rcu_dereference_protected(volume->servers,
8a070a96 DH	360	lockdep_is_held(&volume->servers_lock));
d2ddc776 DH	361	if (afs_annotate_server_list(new, old)) {
d2ddc776 DH	362	new->seq = volume->servers_seq + 1;
8a070a96	363	rcu_assign_pointer(volume->servers, new);
d2ddc776 DH	364	smp_wmb();
	365	volume->servers_seq++;
	366	discard = old;
1da177e4 LT	367	}
1da177e4 LT	368
d2ddc776	369	volume->update_at = ktime_get_real_seconds() + afs_volume_record_life;
d2ddc776 DH	370	write_unlock(&volume->servers_lock);
d2ddc776 DH	371	ret = 0;
1da177e4	372
d2ddc776 DH	373	afs_put_serverlist(volume->cell->net, discard);
	374	error_vldb:
	375	kfree(vldb);
	376	error:
	377	_leave(" = %d", ret);
	378	return ret;
	379	}
1da177e4	380
d2ddc776 DH	381	/*
	382	* Make sure the volume record is up to date.
	383	*/
e49c7b2f	384	int afs_check_volume_status(struct afs_volume volume, struct afs_operation op)
d2ddc776	385	{
d2ddc776	386	int ret, retries = 0;
1da177e4	387
d2ddc776 DH	388	_enter("");
d2ddc776 DH	389
d2ddc776	390	retry:
f6cbb368 DH	391	if (test_bit(AFS_VOLUME_WAIT, &volume->flags))
	392	goto wait;
	393	if (volume->update_at <= ktime_get_real_seconds() \|\|
	394	test_bit(AFS_VOLUME_NEEDS_UPDATE, &volume->flags))
	395	goto update;
	396	_leave(" = 0");
	397	return 0;
	398
	399	update:
d2ddc776	400	if (!test_and_set_bit_lock(AFS_VOLUME_UPDATING, &volume->flags)) {
f6cbb368	401	clear_bit(AFS_VOLUME_NEEDS_UPDATE, &volume->flags);
e49c7b2f	402	ret = afs_update_volume_status(volume, op->key);
f6cbb368 DH	403	if (ret < 0)
f6cbb368 DH	404	set_bit(AFS_VOLUME_NEEDS_UPDATE, &volume->flags);
d2ddc776 DH	405	clear_bit_unlock(AFS_VOLUME_WAIT, &volume->flags);
	406	clear_bit_unlock(AFS_VOLUME_UPDATING, &volume->flags);
	407	wake_up_bit(&volume->flags, AFS_VOLUME_WAIT);
	408	_leave(" = %d", ret);
	409	return ret;
	410	}
1da177e4	411
f6cbb368	412	wait:
d2ddc776 DH	413	if (!test_bit(AFS_VOLUME_WAIT, &volume->flags)) {
	414	_leave(" = 0 [no wait]");
	415	return 0;
	416	}
	417
c4bfda16	418	ret = wait_on_bit(&volume->flags, AFS_VOLUME_WAIT,
e49c7b2f DH	419	(op->flags & AFS_OPERATION_UNINTR) ?
e49c7b2f DH	420	TASK_UNINTERRUPTIBLE : TASK_INTERRUPTIBLE);
d2ddc776 DH	421	if (ret == -ERESTARTSYS) {
	422	_leave(" = %d", ret);
	423	return ret;
	424	}
	425
	426	retries++;
	427	if (retries == 4) {
	428	_leave(" = -ESTALE");
	429	return -ESTALE;
	430	}
	431	goto retry;
ec26815a	432	}