[mirror_ubuntu-bionic-kernel.git] / fs / afs / cell.c

/* AFS cell and server record management
 *
 * Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * 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/module.h>
#include <linux/slab.h>
#include <linux/key.h>
#include <linux/ctype.h>
#include <linux/sched.h>
#include <keys/rxrpc-type.h>
#include "internal.h"

DECLARE_RWSEM(afs_proc_cells_sem);
LIST_HEAD(afs_proc_cells);

static struct list_head afs_cells = LIST_HEAD_INIT(afs_cells);
static DEFINE_RWLOCK(afs_cells_lock);
static DECLARE_RWSEM(afs_cells_sem); /* add/remove serialisation */
static DECLARE_WAIT_QUEUE_HEAD(afs_cells_freeable_wq);
static struct afs_cell *afs_cell_root;

/*
 * allocate a cell record and fill in its name, VL server address list and
 * allocate an anonymous key
 */
static struct afs_cell *afs_cell_alloc(const char *name, char *vllist)
{
	struct afs_cell *cell;
	size_t namelen;
	char keyname[4 + AFS_MAXCELLNAME + 1], *cp, *dp, *next;
	int ret;

	_enter("%s,%s", name, vllist);

	BUG_ON(!name); /* TODO: want to look up "this cell" in the cache */

	namelen = strlen(name);
	if (namelen > AFS_MAXCELLNAME)
		return ERR_PTR(-ENAMETOOLONG);

	/* allocate and initialise a cell record */
	cell = kzalloc(sizeof(struct afs_cell) + namelen + 1, GFP_KERNEL);
	if (!cell) {
		_leave(" = -ENOMEM");
		return ERR_PTR(-ENOMEM);
	}

	memcpy(cell->name, name, namelen);
	cell->name[namelen] = 0;

	atomic_set(&cell->usage, 1);
	INIT_LIST_HEAD(&cell->link);
	rwlock_init(&cell->servers_lock);
	INIT_LIST_HEAD(&cell->servers);
	init_rwsem(&cell->vl_sem);
	INIT_LIST_HEAD(&cell->vl_list);
	spin_lock_init(&cell->vl_lock);

	/* fill in the VL server list from the rest of the string */
	do {
		unsigned a, b, c, d;

		next = strchr(vllist, ':');
		if (next)
			*next++ = 0;

		if (sscanf(vllist, "%u.%u.%u.%u", &a, &b, &c, &d) != 4)
			goto bad_address;

		if (a > 255 || b > 255 || c > 255 || d > 255)
			goto bad_address;

		cell->vl_addrs[cell->vl_naddrs++].s_addr =
			htonl((a << 24) | (b << 16) | (c << 8) | d);

	} while (cell->vl_naddrs < AFS_CELL_MAX_ADDRS && (vllist = next));

	/* create a key to represent an anonymous user */
	memcpy(keyname, "afs@", 4);
	dp = keyname + 4;
	cp = cell->name;
	do {
		*dp++ = toupper(*cp);
	} while (*cp++);
	cell->anonymous_key = key_alloc(&key_type_rxrpc, keyname, 0, 0, current,
					KEY_POS_SEARCH, KEY_ALLOC_NOT_IN_QUOTA);
	if (IS_ERR(cell->anonymous_key)) {
		_debug("no key");
		ret = PTR_ERR(cell->anonymous_key);
		goto error;
	}

	ret = key_instantiate_and_link(cell->anonymous_key, NULL, 0,
				       NULL, NULL);
	if (ret < 0) {
		_debug("instantiate failed");
		goto error;
	}

	_debug("anon key %p{%x}",
	       cell->anonymous_key, key_serial(cell->anonymous_key));

	_leave(" = %p", cell);
	return cell;

bad_address:
	printk(KERN_ERR "kAFS: bad VL server IP address\n");
	ret = -EINVAL;
error:
	key_put(cell->anonymous_key);
	kfree(cell);
	_leave(" = %d", ret);
	return ERR_PTR(ret);
}

/*
 * create a cell record
 * - "name" is the name of the cell
 * - "vllist" is a colon separated list of IP addresses in "a.b.c.d" format
 */
struct afs_cell *afs_cell_create(const char *name, char *vllist)
{
	struct afs_cell *cell;
	int ret;

	_enter("%s,%s", name, vllist);

	cell = afs_cell_alloc(name, vllist);
	if (IS_ERR(cell)) {
		_leave(" = %ld", PTR_ERR(cell));
		return cell;
	}

	down_write(&afs_cells_sem);

	/* add a proc directory for this cell */
	ret = afs_proc_cell_setup(cell);
	if (ret < 0)
		goto error;

#ifdef AFS_CACHING_SUPPORT
	/* put it up for caching */
	cachefs_acquire_cookie(afs_cache_netfs.primary_index,
			       &afs_vlocation_cache_index_def,
			       cell,
			       &cell->cache);
#endif

	/* add to the cell lists */
	write_lock(&afs_cells_lock);
	list_add_tail(&cell->link, &afs_cells);
	write_unlock(&afs_cells_lock);

	down_write(&afs_proc_cells_sem);
	list_add_tail(&cell->proc_link, &afs_proc_cells);
	up_write(&afs_proc_cells_sem);
	up_write(&afs_cells_sem);

	_leave(" = %p", cell);
	return cell;

error:
	up_write(&afs_cells_sem);
	key_put(cell->anonymous_key);
	kfree(cell);
	_leave(" = %d", ret);
	return ERR_PTR(ret);
}

/*
 * set the root cell information
 * - can be called with a module parameter string
 * - can be called from a write to /proc/fs/afs/rootcell
 */
int afs_cell_init(char *rootcell)
{
	struct afs_cell *old_root, *new_root;
	char *cp;

	_enter("");

	if (!rootcell) {
		/* module is loaded with no parameters, or built statically.
		 * - in the future we might initialize cell DB here.
		 */
		_leave(" = 0 [no root]");
		return 0;
	}

	cp = strchr(rootcell, ':');
	if (!cp) {
		printk(KERN_ERR "kAFS: no VL server IP addresses specified\n");
		_leave(" = -EINVAL");
		return -EINVAL;
	}

	/* allocate a cell record for the root cell */
	*cp++ = 0;
	new_root = afs_cell_create(rootcell, cp);
	if (IS_ERR(new_root)) {
		_leave(" = %ld", PTR_ERR(new_root));
		return PTR_ERR(new_root);
	}

	/* install the new cell */
	write_lock(&afs_cells_lock);
	old_root = afs_cell_root;
	afs_cell_root = new_root;
	write_unlock(&afs_cells_lock);
	afs_put_cell(old_root);

	_leave(" = 0");
	return 0;
}

/*
 * lookup a cell record
 */
struct afs_cell *afs_cell_lookup(const char *name, unsigned namesz)
{
	struct afs_cell *cell;

	_enter("\"%*.*s\",", namesz, namesz, name ? name : "");

	down_read(&afs_cells_sem);
	read_lock(&afs_cells_lock);

	if (name) {
		/* if the cell was named, look for it in the cell record list */
		list_for_each_entry(cell, &afs_cells, link) {
			if (strncmp(cell->name, name, namesz) == 0) {
				afs_get_cell(cell);
				goto found;
			}
		}
		cell = ERR_PTR(-ENOENT);
	found:
		;
	} else {
		cell = afs_cell_root;
		if (!cell) {
			/* this should not happen unless user tries to mount
			 * when root cell is not set. Return an impossibly
			 * bizzare errno to alert the user. Things like
			 * ENOENT might be "more appropriate" but they happen
			 * for other reasons.
			 */
			cell = ERR_PTR(-EDESTADDRREQ);
		} else {
			afs_get_cell(cell);
		}

	}

	read_unlock(&afs_cells_lock);
	up_read(&afs_cells_sem);
	_leave(" = %p", cell);
	return cell;
}

#if 0
/*
 * try and get a cell record
 */
struct afs_cell *afs_get_cell_maybe(struct afs_cell *cell)
{
	write_lock(&afs_cells_lock);

	if (cell && !list_empty(&cell->link))
		afs_get_cell(cell);
	else
		cell = NULL;

	write_unlock(&afs_cells_lock);
	return cell;
}
#endif  /*  0  */

/*
 * destroy a cell record
 */
void afs_put_cell(struct afs_cell *cell)
{
	if (!cell)
		return;

	_enter("%p{%d,%s}", cell, atomic_read(&cell->usage), cell->name);

	ASSERTCMP(atomic_read(&cell->usage), >, 0);

	/* to prevent a race, the decrement and the dequeue must be effectively
	 * atomic */
	write_lock(&afs_cells_lock);

	if (likely(!atomic_dec_and_test(&cell->usage))) {
		write_unlock(&afs_cells_lock);
		_leave("");
		return;
	}

	ASSERT(list_empty(&cell->servers));
	ASSERT(list_empty(&cell->vl_list));

	write_unlock(&afs_cells_lock);

	wake_up(&afs_cells_freeable_wq);

	_leave(" [unused]");
}

/*
 * destroy a cell record
 * - must be called with the afs_cells_sem write-locked
 * - cell->link should have been broken by the caller
 */
static void afs_cell_destroy(struct afs_cell *cell)
{
	_enter("%p{%d,%s}", cell, atomic_read(&cell->usage), cell->name);

	ASSERTCMP(atomic_read(&cell->usage), >=, 0);
	ASSERT(list_empty(&cell->link));

	/* wait for everyone to stop using the cell */
	if (atomic_read(&cell->usage) > 0) {
		DECLARE_WAITQUEUE(myself, current);

		_debug("wait for cell %s", cell->name);
		set_current_state(TASK_UNINTERRUPTIBLE);
		add_wait_queue(&afs_cells_freeable_wq, &myself);

		while (atomic_read(&cell->usage) > 0) {
			schedule();
			set_current_state(TASK_UNINTERRUPTIBLE);
		}

		remove_wait_queue(&afs_cells_freeable_wq, &myself);
		set_current_state(TASK_RUNNING);
	}

	_debug("cell dead");
	ASSERTCMP(atomic_read(&cell->usage), ==, 0);
	ASSERT(list_empty(&cell->servers));
	ASSERT(list_empty(&cell->vl_list));

	afs_proc_cell_remove(cell);

	down_write(&afs_proc_cells_sem);
	list_del_init(&cell->proc_link);
	up_write(&afs_proc_cells_sem);

#ifdef AFS_CACHING_SUPPORT
	cachefs_relinquish_cookie(cell->cache, 0);
#endif

	key_put(cell->anonymous_key);
	kfree(cell);

	_leave(" [destroyed]");
}

/*
 * purge in-memory cell database on module unload or afs_init() failure
 * - the timeout daemon is stopped before calling this
 */
void afs_cell_purge(void)
{
	struct afs_cell *cell;

	_enter("");

	afs_put_cell(afs_cell_root);

	down_write(&afs_cells_sem);

	while (!list_empty(&afs_cells)) {
		cell = NULL;

		/* remove the next cell from the front of the list */
		write_lock(&afs_cells_lock);

		if (!list_empty(&afs_cells)) {
			cell = list_entry(afs_cells.next,
					  struct afs_cell, link);
			list_del_init(&cell->link);
		}

		write_unlock(&afs_cells_lock);

		if (cell) {
			_debug("PURGING CELL %s (%d)",
			       cell->name, atomic_read(&cell->usage));

			/* now the cell should be left with no references */
			afs_cell_destroy(cell);
		}
	}

	up_write(&afs_cells_sem);
	_leave("");
}
Commit	Line	Data
ec26815a	1	/* AFS cell and server record management
1da177e4 LT	2	*
	3	* Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
	4	* 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 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/module.h>
1da177e4	13	#include <linux/slab.h>
00d3b7a4 DH	14	#include <linux/key.h>
00d3b7a4 DH	15	#include <linux/ctype.h>
e8edc6e0	16	#include <linux/sched.h>
00d3b7a4	17	#include <keys/rxrpc-type.h>
1da177e4 LT	18	#include "internal.h"
	19
	20	DECLARE_RWSEM(afs_proc_cells_sem);
	21	LIST_HEAD(afs_proc_cells);
	22
	23	static struct list_head afs_cells = LIST_HEAD_INIT(afs_cells);
	24	static DEFINE_RWLOCK(afs_cells_lock);
	25	static DECLARE_RWSEM(afs_cells_sem); /* add/remove serialisation */
08e0e7c8	26	static DECLARE_WAIT_QUEUE_HEAD(afs_cells_freeable_wq);
1da177e4 LT	27	static struct afs_cell *afs_cell_root;
1da177e4 LT	28
1da177e4	29	/*
00d3b7a4 DH	30	* allocate a cell record and fill in its name, VL server address list and
00d3b7a4 DH	31	* allocate an anonymous key
1da177e4	32	*/
00d3b7a4	33	static struct afs_cell afs_cell_alloc(const char name, char *vllist)
1da177e4 LT	34	{
1da177e4 LT	35	struct afs_cell *cell;
00d3b7a4 DH	36	size_t namelen;
00d3b7a4 DH	37	char keyname[4 + AFS_MAXCELLNAME + 1], cp, dp, *next;
1da177e4 LT	38	int ret;
1da177e4 LT	39
08e0e7c8	40	_enter("%s,%s", name, vllist);
1da177e4 LT	41
	42	BUG_ON(!name); /* TODO: want to look up "this cell" in the cache */
	43
00d3b7a4 DH	44	namelen = strlen(name);
	45	if (namelen > AFS_MAXCELLNAME)
	46	return ERR_PTR(-ENAMETOOLONG);
	47
1da177e4	48	/* allocate and initialise a cell record */
00d3b7a4	49	cell = kzalloc(sizeof(struct afs_cell) + namelen + 1, GFP_KERNEL);
1da177e4 LT	50	if (!cell) {
1da177e4 LT	51	_leave(" = -ENOMEM");
08e0e7c8	52	return ERR_PTR(-ENOMEM);
1da177e4 LT	53	}
1da177e4 LT	54
00d3b7a4 DH	55	memcpy(cell->name, name, namelen);
00d3b7a4 DH	56	cell->name[namelen] = 0;
1da177e4	57
08e0e7c8	58	atomic_set(&cell->usage, 1);
1da177e4	59	INIT_LIST_HEAD(&cell->link);
08e0e7c8 DH	60	rwlock_init(&cell->servers_lock);
08e0e7c8 DH	61	INIT_LIST_HEAD(&cell->servers);
1da177e4 LT	62	init_rwsem(&cell->vl_sem);
1da177e4 LT	63	INIT_LIST_HEAD(&cell->vl_list);
08e0e7c8	64	spin_lock_init(&cell->vl_lock);
1da177e4	65
1da177e4	66	/* fill in the VL server list from the rest of the string */
1da177e4 LT	67	do {
	68	unsigned a, b, c, d;
	69
	70	next = strchr(vllist, ':');
	71	if (next)
	72	*next++ = 0;
	73
	74	if (sscanf(vllist, "%u.%u.%u.%u", &a, &b, &c, &d) != 4)
00d3b7a4	75	goto bad_address;
1da177e4 LT	76
1da177e4 LT	77	if (a > 255 \|\| b > 255 \|\| c > 255 \|\| d > 255)
00d3b7a4	78	goto bad_address;
1da177e4 LT	79
	80	cell->vl_addrs[cell->vl_naddrs++].s_addr =
	81	htonl((a << 24) \| (b << 16) \| (c << 8) \| d);
	82
00d3b7a4 DH	83	} while (cell->vl_naddrs < AFS_CELL_MAX_ADDRS && (vllist = next));
	84
	85	/* create a key to represent an anonymous user */
	86	memcpy(keyname, "afs@", 4);
	87	dp = keyname + 4;
	88	cp = cell->name;
	89	do {
	90	dp++ = toupper(cp);
	91	} while (*cp++);
	92	cell->anonymous_key = key_alloc(&key_type_rxrpc, keyname, 0, 0, current,
	93	KEY_POS_SEARCH, KEY_ALLOC_NOT_IN_QUOTA);
	94	if (IS_ERR(cell->anonymous_key)) {
	95	_debug("no key");
	96	ret = PTR_ERR(cell->anonymous_key);
	97	goto error;
	98	}
	99
	100	ret = key_instantiate_and_link(cell->anonymous_key, NULL, 0,
	101	NULL, NULL);
	102	if (ret < 0) {
	103	_debug("instantiate failed");
	104	goto error;
	105	}
	106
	107	_debug("anon key %p{%x}",
	108	cell->anonymous_key, key_serial(cell->anonymous_key));
	109
	110	_leave(" = %p", cell);
	111	return cell;
	112
	113	bad_address:
	114	printk(KERN_ERR "kAFS: bad VL server IP address\n");
	115	ret = -EINVAL;
	116	error:
	117	key_put(cell->anonymous_key);
	118	kfree(cell);
	119	_leave(" = %d", ret);
	120	return ERR_PTR(ret);
	121	}
1da177e4	122
00d3b7a4 DH	123	/*
	124	* create a cell record
	125	* - "name" is the name of the cell
	126	* - "vllist" is a colon separated list of IP addresses in "a.b.c.d" format
	127	*/
	128	struct afs_cell afs_cell_create(const char name, char *vllist)
	129	{
	130	struct afs_cell *cell;
	131	int ret;
	132
	133	_enter("%s,%s", name, vllist);
	134
	135	cell = afs_cell_alloc(name, vllist);
	136	if (IS_ERR(cell)) {
	137	_leave(" = %ld", PTR_ERR(cell));
	138	return cell;
	139	}
	140
	141	down_write(&afs_cells_sem);
1da177e4	142
08e0e7c8	143	/* add a proc directory for this cell */
1da177e4 LT	144	ret = afs_proc_cell_setup(cell);
	145	if (ret < 0)
	146	goto error;
	147
	148	#ifdef AFS_CACHING_SUPPORT
	149	/* put it up for caching */
	150	cachefs_acquire_cookie(afs_cache_netfs.primary_index,
	151	&afs_vlocation_cache_index_def,
	152	cell,
	153	&cell->cache);
	154	#endif
	155
	156	/* add to the cell lists */
	157	write_lock(&afs_cells_lock);
	158	list_add_tail(&cell->link, &afs_cells);
	159	write_unlock(&afs_cells_lock);
	160
	161	down_write(&afs_proc_cells_sem);
	162	list_add_tail(&cell->proc_link, &afs_proc_cells);
	163	up_write(&afs_proc_cells_sem);
1da177e4 LT	164	up_write(&afs_cells_sem);
1da177e4 LT	165
08e0e7c8 DH	166	_leave(" = %p", cell);
08e0e7c8 DH	167	return cell;
1da177e4	168
ec26815a	169	error:
1da177e4	170	up_write(&afs_cells_sem);
00d3b7a4	171	key_put(cell->anonymous_key);
1da177e4 LT	172	kfree(cell);
1da177e4 LT	173	_leave(" = %d", ret);
08e0e7c8	174	return ERR_PTR(ret);
ec26815a	175	}
1da177e4	176
1da177e4	177	/*
08e0e7c8 DH	178	* set the root cell information
	179	* - can be called with a module parameter string
	180	* - can be called from a write to /proc/fs/afs/rootcell
1da177e4 LT	181	*/
	182	int afs_cell_init(char *rootcell)
	183	{
	184	struct afs_cell old_root, new_root;
	185	char *cp;
1da177e4 LT	186
	187	_enter("");
	188
	189	if (!rootcell) {
	190	/* module is loaded with no parameters, or built statically.
	191	* - in the future we might initialize cell DB here.
	192	*/
08e0e7c8	193	_leave(" = 0 [no root]");
1da177e4 LT	194	return 0;
	195	}
	196
	197	cp = strchr(rootcell, ':');
	198	if (!cp) {
	199	printk(KERN_ERR "kAFS: no VL server IP addresses specified\n");
08e0e7c8	200	_leave(" = -EINVAL");
1da177e4 LT	201	return -EINVAL;
	202	}
	203
	204	/* allocate a cell record for the root cell */
	205	*cp++ = 0;
08e0e7c8 DH	206	new_root = afs_cell_create(rootcell, cp);
	207	if (IS_ERR(new_root)) {
	208	_leave(" = %ld", PTR_ERR(new_root));
	209	return PTR_ERR(new_root);
1da177e4 LT	210	}
1da177e4 LT	211
08e0e7c8	212	/* install the new cell */
1da177e4	213	write_lock(&afs_cells_lock);
08e0e7c8	214	old_root = afs_cell_root;
1da177e4 LT	215	afs_cell_root = new_root;
1da177e4 LT	216	write_unlock(&afs_cells_lock);
08e0e7c8	217	afs_put_cell(old_root);
1da177e4	218
08e0e7c8 DH	219	_leave(" = 0");
08e0e7c8 DH	220	return 0;
ec26815a	221	}
1da177e4	222
1da177e4 LT	223	/*
	224	* lookup a cell record
	225	*/
08e0e7c8	226	struct afs_cell afs_cell_lookup(const char name, unsigned namesz)
1da177e4 LT	227	{
1da177e4 LT	228	struct afs_cell *cell;
1da177e4 LT	229
	230	_enter("\"%.s\",", namesz, namesz, name ? name : "");
	231
08e0e7c8 DH	232	down_read(&afs_cells_sem);
08e0e7c8 DH	233	read_lock(&afs_cells_lock);
1da177e4 LT	234
	235	if (name) {
	236	/* if the cell was named, look for it in the cell record list */
1da177e4 LT	237	list_for_each_entry(cell, &afs_cells, link) {
	238	if (strncmp(cell->name, name, namesz) == 0) {
	239	afs_get_cell(cell);
	240	goto found;
	241	}
	242	}
08e0e7c8	243	cell = ERR_PTR(-ENOENT);
1da177e4	244	found:
08e0e7c8	245	;
ec26815a	246	} else {
1da177e4 LT	247	cell = afs_cell_root;
	248	if (!cell) {
	249	/* this should not happen unless user tries to mount
	250	* when root cell is not set. Return an impossibly
	251	* bizzare errno to alert the user. Things like
	252	* ENOENT might be "more appropriate" but they happen
	253	* for other reasons.
	254	*/
08e0e7c8	255	cell = ERR_PTR(-EDESTADDRREQ);
ec26815a	256	} else {
1da177e4	257	afs_get_cell(cell);
1da177e4 LT	258	}
1da177e4 LT	259
1da177e4 LT	260	}
1da177e4 LT	261
08e0e7c8 DH	262	read_unlock(&afs_cells_lock);
	263	up_read(&afs_cells_sem);
	264	_leave(" = %p", cell);
	265	return cell;
ec26815a	266	}
1da177e4	267
c1206a2c	268	#if 0
1da177e4 LT	269	/*
	270	* try and get a cell record
	271	*/
08e0e7c8	272	struct afs_cell afs_get_cell_maybe(struct afs_cell cell)
1da177e4	273	{
1da177e4 LT	274	write_lock(&afs_cells_lock);
1da177e4 LT	275
1da177e4 LT	276	if (cell && !list_empty(&cell->link))
	277	afs_get_cell(cell);
	278	else
	279	cell = NULL;
	280
	281	write_unlock(&afs_cells_lock);
1da177e4	282	return cell;
ec26815a	283	}
c1206a2c	284	#endif /* 0 */
1da177e4	285
1da177e4 LT	286	/*
	287	* destroy a cell record
	288	*/
	289	void afs_put_cell(struct afs_cell *cell)
	290	{
	291	if (!cell)
	292	return;
	293
	294	_enter("%p{%d,%s}", cell, atomic_read(&cell->usage), cell->name);
	295
08e0e7c8	296	ASSERTCMP(atomic_read(&cell->usage), >, 0);
1da177e4 LT	297
	298	/* to prevent a race, the decrement and the dequeue must be effectively
	299	* atomic */
	300	write_lock(&afs_cells_lock);
	301
	302	if (likely(!atomic_dec_and_test(&cell->usage))) {
	303	write_unlock(&afs_cells_lock);
	304	_leave("");
	305	return;
	306	}
	307
08e0e7c8 DH	308	ASSERT(list_empty(&cell->servers));
	309	ASSERT(list_empty(&cell->vl_list));
	310
1da177e4 LT	311	write_unlock(&afs_cells_lock);
1da177e4 LT	312
08e0e7c8	313	wake_up(&afs_cells_freeable_wq);
1da177e4 LT	314
1da177e4 LT	315	_leave(" [unused]");
ec26815a	316	}
1da177e4	317
1da177e4 LT	318	/*
1da177e4 LT	319	* destroy a cell record
08e0e7c8 DH	320	* - must be called with the afs_cells_sem write-locked
08e0e7c8 DH	321	* - cell->link should have been broken by the caller
1da177e4 LT	322	*/
	323	static void afs_cell_destroy(struct afs_cell *cell)
	324	{
	325	_enter("%p{%d,%s}", cell, atomic_read(&cell->usage), cell->name);
	326
08e0e7c8 DH	327	ASSERTCMP(atomic_read(&cell->usage), >=, 0);
08e0e7c8 DH	328	ASSERT(list_empty(&cell->link));
1da177e4	329
08e0e7c8 DH	330	/* wait for everyone to stop using the cell */
	331	if (atomic_read(&cell->usage) > 0) {
	332	DECLARE_WAITQUEUE(myself, current);
1da177e4	333
08e0e7c8 DH	334	_debug("wait for cell %s", cell->name);
	335	set_current_state(TASK_UNINTERRUPTIBLE);
	336	add_wait_queue(&afs_cells_freeable_wq, &myself);
1da177e4	337
08e0e7c8 DH	338	while (atomic_read(&cell->usage) > 0) {
	339	schedule();
	340	set_current_state(TASK_UNINTERRUPTIBLE);
	341	}
1da177e4	342
08e0e7c8 DH	343	remove_wait_queue(&afs_cells_freeable_wq, &myself);
	344	set_current_state(TASK_RUNNING);
	345	}
	346
	347	_debug("cell dead");
	348	ASSERTCMP(atomic_read(&cell->usage), ==, 0);
	349	ASSERT(list_empty(&cell->servers));
	350	ASSERT(list_empty(&cell->vl_list));
1da177e4 LT	351
	352	afs_proc_cell_remove(cell);
	353
	354	down_write(&afs_proc_cells_sem);
	355	list_del_init(&cell->proc_link);
	356	up_write(&afs_proc_cells_sem);
	357
	358	#ifdef AFS_CACHING_SUPPORT
	359	cachefs_relinquish_cookie(cell->cache, 0);
	360	#endif
	361
00d3b7a4	362	key_put(cell->anonymous_key);
1da177e4 LT	363	kfree(cell);
	364
	365	_leave(" [destroyed]");
ec26815a	366	}
1da177e4	367
1da177e4 LT	368	/*
	369	* purge in-memory cell database on module unload or afs_init() failure
	370	* - the timeout daemon is stopped before calling this
	371	*/
	372	void afs_cell_purge(void)
	373	{
1da177e4 LT	374	struct afs_cell *cell;
	375
	376	_enter("");
	377
	378	afs_put_cell(afs_cell_root);
	379
08e0e7c8 DH	380	down_write(&afs_cells_sem);
08e0e7c8 DH	381
1da177e4 LT	382	while (!list_empty(&afs_cells)) {
	383	cell = NULL;
	384
	385	/* remove the next cell from the front of the list */
	386	write_lock(&afs_cells_lock);
	387
	388	if (!list_empty(&afs_cells)) {
	389	cell = list_entry(afs_cells.next,
	390	struct afs_cell, link);
	391	list_del_init(&cell->link);
	392	}
	393
	394	write_unlock(&afs_cells_lock);
	395
	396	if (cell) {
	397	_debug("PURGING CELL %s (%d)",
	398	cell->name, atomic_read(&cell->usage));
	399
1da177e4 LT	400	/* now the cell should be left with no references */
	401	afs_cell_destroy(cell);
	402	}
	403	}
	404
08e0e7c8	405	up_write(&afs_cells_sem);
1da177e4	406	_leave("");
ec26815a	407	}