[deliverable/linux.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 <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;
}

/*
 * 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;
}

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