Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit b7aa3d39 authored by Josef Bacik's avatar Josef Bacik Committed by Jens Axboe
Browse files

nbd: add a reconfigure netlink command 



We want to be able to reconnect dead connections to existing block
devices, so add a reconfigure netlink command.  We will also allow users
to change their timeout on the fly, but everything else will require a
disconnect and reconnect.  You won't be able to add more connections
either, simply replace dead connections with new more lively
connections.

Signed-off-by: default avatarJosef Bacik <jbacik@fb.com>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent e46c7287

drivers/block/nbd.c

+141 −0
Original line number Diff line number Diff line
@@ -785,6 +785,59 @@ static int nbd_add_socket(struct nbd_device *nbd, unsigned long arg, 
	return 0;

}



static int nbd_reconnect_socket(struct nbd_device *nbd, unsigned long arg)

{

	struct nbd_config *config = nbd->config;

	struct socket *sock, *old;

	struct recv_thread_args *args;

	int i;

	int err;



	sock = sockfd_lookup(arg, &err);

	if (!sock)

		return err;



	args = kzalloc(sizeof(*args), GFP_KERNEL);

	if (!args) {

		sockfd_put(sock);

		return -ENOMEM;

	}



	for (i = 0; i < config->num_connections; i++) {

		struct nbd_sock *nsock = config->socks[i];



		if (!nsock->dead)

			continue;



		mutex_lock(&nsock->tx_lock);

		if (!nsock->dead) {

			mutex_unlock(&nsock->tx_lock);

			continue;

		}

		sk_set_memalloc(sock->sk);

		atomic_inc(&config->recv_threads);

		refcount_inc(&nbd->config_refs);

		old = nsock->sock;

		nsock->fallback_index = -1;

		nsock->sock = sock;

		nsock->dead = false;

		INIT_WORK(&args->work, recv_work);

		args->index = i;

		args->nbd = nbd;

		mutex_unlock(&nsock->tx_lock);

		sockfd_put(old);



		/* We take the tx_mutex in an error path in the recv_work, so we

		 * need to queue_work outside of the tx_mutex.

		 */

		queue_work(recv_workqueue, &args->work);

		return 0;

	}

	sockfd_put(sock);

	kfree(args);

	return -ENOSPC;

}



/* Reset all properties of an NBD device */

static void nbd_reset(struct nbd_device *nbd)

{
@@ -1528,6 +1581,89 @@ static int nbd_genl_disconnect(struct sk_buff *skb, struct genl_info *info) 
	return 0;

}



static int nbd_genl_reconfigure(struct sk_buff *skb, struct genl_info *info)

{

	struct nbd_device *nbd = NULL;

	struct nbd_config *config;

	int index;

	int ret = -EINVAL;



	if (!netlink_capable(skb, CAP_SYS_ADMIN))

		return -EPERM;



	if (!info->attrs[NBD_ATTR_INDEX]) {

		printk(KERN_ERR "nbd: must specify a device to reconfigure\n");

		return -EINVAL;

	}

	index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);

	mutex_lock(&nbd_index_mutex);

	nbd = idr_find(&nbd_index_idr, index);

	mutex_unlock(&nbd_index_mutex);

	if (!nbd) {

		printk(KERN_ERR "nbd: couldn't find a device at index %d\n",

		       index);

		return -EINVAL;

	}



	if (!refcount_inc_not_zero(&nbd->config_refs)) {

		dev_err(nbd_to_dev(nbd),

			"not configured, cannot reconfigure\n");

		return -EINVAL;

	}



	mutex_lock(&nbd->config_lock);

	config = nbd->config;

	if (!test_bit(NBD_BOUND, &config->runtime_flags) ||

	    !nbd->task_recv) {

		dev_err(nbd_to_dev(nbd),

			"not configured, cannot reconfigure\n");

		goto out;

	}



	if (info->attrs[NBD_ATTR_TIMEOUT]) {

		u64 timeout = nla_get_u64(info->attrs[NBD_ATTR_TIMEOUT]);

		nbd->tag_set.timeout = timeout * HZ;

		blk_queue_rq_timeout(nbd->disk->queue, timeout * HZ);

	}



	if (info->attrs[NBD_ATTR_SOCKETS]) {

		struct nlattr *attr;

		int rem, fd;



		nla_for_each_nested(attr, info->attrs[NBD_ATTR_SOCKETS],

				    rem) {

			struct nlattr *socks[NBD_SOCK_MAX+1];



			if (nla_type(attr) != NBD_SOCK_ITEM) {

				printk(KERN_ERR "nbd: socks must be embedded in a SOCK_ITEM attr\n");

				ret = -EINVAL;

				goto out;

			}

			ret = nla_parse_nested(socks, NBD_SOCK_MAX, attr,

					       nbd_sock_policy);

			if (ret != 0) {

				printk(KERN_ERR "nbd: error processing sock list\n");

				ret = -EINVAL;

				goto out;

			}

			if (!socks[NBD_SOCK_FD])

				continue;

			fd = (int)nla_get_u32(socks[NBD_SOCK_FD]);

			ret = nbd_reconnect_socket(nbd, fd);

			if (ret) {

				if (ret == -ENOSPC)

					ret = 0;

				goto out;

			}

			dev_info(nbd_to_dev(nbd), "reconnected socket\n");

		}

	}

out:

	mutex_unlock(&nbd->config_lock);

	nbd_config_put(nbd);

	return ret;

}



static const struct genl_ops nbd_connect_genl_ops[] = {

	{

		.cmd	= NBD_CMD_CONNECT,
@@ -1539,6 +1675,11 @@ static const struct genl_ops nbd_connect_genl_ops[] = { 
		.policy	= nbd_attr_policy,

		.doit	= nbd_genl_disconnect,

	},

	{

		.cmd	= NBD_CMD_RECONFIGURE,

		.policy	= nbd_attr_policy,

		.doit	= nbd_genl_reconfigure,

	},

};



static struct genl_family nbd_genl_family __ro_after_init = {

include/uapi/linux/nbd-netlink.h

+1 −0
Original line number Diff line number Diff line
@@ -62,6 +62,7 @@ enum { 
	NBD_CMD_UNSPEC,

	NBD_CMD_CONNECT,

	NBD_CMD_DISCONNECT,

	NBD_CMD_RECONFIGURE,

	__NBD_CMD_MAX,

};

#define NBD_CMD_MAX	(__NBD_CMD_MAX - 1)