path: root/fs/afs/vlocation.c

/* vlocation.c: volume location 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/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/pagemap.h>
#include "volume.h"
#include "cell.h"
#include "cmservice.h"
#include "fsclient.h"
#include "vlclient.h"
#include "kafstimod.h"
#include <rxrpc/connection.h>
#include "internal.h"

#define AFS_VLDB_TIMEOUT HZ*1000

static void afs_vlocation_update_timer(struct afs_timer *timer);
static void afs_vlocation_update_attend(struct afs_async_op *op);
static void afs_vlocation_update_discard(struct afs_async_op *op);
static void __afs_put_vlocation(struct afs_vlocation *vlocation);

static void __afs_vlocation_timeout(struct afs_timer *timer)
{
	struct afs_vlocation *vlocation =
		list_entry(timer, struct afs_vlocation, timeout);

	_debug("VL TIMEOUT [%s{u=%d}]",
	       vlocation->vldb.name, atomic_read(&vlocation->usage));

	afs_vlocation_do_timeout(vlocation);
}

static const struct afs_timer_ops afs_vlocation_timer_ops = {
	.timed_out	= __afs_vlocation_timeout,
};

static const struct afs_timer_ops afs_vlocation_update_timer_ops = {
	.timed_out	= afs_vlocation_update_timer,
};

static const struct afs_async_op_ops afs_vlocation_update_op_ops = {
	.attend		= afs_vlocation_update_attend,
	.discard	= afs_vlocation_update_discard,
};

static LIST_HEAD(afs_vlocation_update_pendq);	/* queue of VLs awaiting update */
static struct afs_vlocation *afs_vlocation_update;	/* VL currently being updated */
static DEFINE_SPINLOCK(afs_vlocation_update_lock); /* lock guarding update queue */

#ifdef AFS_CACHING_SUPPORT
static cachefs_match_val_t afs_vlocation_cache_match(void *target,
						     const void *entry);
static void afs_vlocation_cache_update(void *source, void *entry);

struct cachefs_index_def afs_vlocation_cache_index_def = {
	.name		= "vldb",
	.data_size	= sizeof(struct afs_cache_vlocation),
	.keys[0]	= { CACHEFS_INDEX_KEYS_ASCIIZ, 64 },
	.match		= afs_vlocation_cache_match,
	.update		= afs_vlocation_cache_update,
};
#endif

/*****************************************************************************/
/*
 * iterate through the VL servers in a cell until one of them admits knowing
 * about the volume in question
 * - caller must have cell->vl_sem write-locked
 */
static int afs_vlocation_access_vl_by_name(struct afs_vlocation *vlocation,
					   const char *name,
					   unsigned namesz,
					   struct afs_cache_vlocation *vldb)
{
	struct afs_server *server = NULL;
	struct afs_cell *cell = vlocation->cell;
	int count, ret;

	_enter("%s,%*.*s,%u", cell->name, namesz, namesz, name, namesz);

	ret = -ENOMEDIUM;
	for (count = cell->vl_naddrs; count > 0; count--) {
		_debug("CellServ[%hu]: %08x",
		       cell->vl_curr_svix,
		       cell->vl_addrs[cell->vl_curr_svix].s_addr);

		/* try and create a server */
		ret = afs_server_lookup(cell,
					&cell->vl_addrs[cell->vl_curr_svix],
					&server);
		switch (ret) {
		case 0:
			break;
		case -ENOMEM:
		case -ENONET:
			goto out;
		default:
			goto rotate;
		}

		/* attempt to access the VL server */
		ret = afs_rxvl_get_entry_by_name(server, name, namesz, vldb);
		switch (ret) {
		case 0:
			afs_put_server(server);
			goto out;
		case -ENOMEM:
		case -ENONET:
		case -ENETUNREACH:
		case -EHOSTUNREACH:
		case -ECONNREFUSED:
			down_write(&server->sem);
			if (server->vlserver) {
				rxrpc_put_connection(server->vlserver);
				server->vlserver = NULL;
			}
			up_write(&server->sem);
			afs_put_server(server);
			if (ret == -ENOMEM || ret == -ENONET)
				goto out;
			goto rotate;
		case -ENOMEDIUM:
			afs_put_server(server);
			goto out;
		default:
			afs_put_server(server);
			ret = -ENOMEDIUM;
			goto rotate;
		}

		/* rotate the server records upon lookup failure */
	rotate:
		cell->vl_curr_svix++;
		cell->vl_curr_svix %= cell->vl_naddrs;
	}

 out:
	_leave(" = %d", ret);
	return ret;

} /* end afs_vlocation_access_vl_by_name() */

/*****************************************************************************/
/*
 * iterate through the VL servers in a cell until one of them admits knowing
 * about the volume in question
 * - caller must have cell->vl_sem write-locked
 */
static int afs_vlocation_access_vl_by_id(struct afs_vlocation *vlocation,
					 afs_volid_t volid,
					 afs_voltype_t voltype,
					 struct afs_cache_vlocation *vldb)
{