diff options
Diffstat (limited to 'drivers/block/nbd.c')
| -rw-r--r-- | drivers/block/nbd.c | 108 |
1 files changed, 108 insertions, 0 deletions
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index c5f866bcfea6..cb45d799bc5c 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -45,6 +45,7 @@ static DEFINE_IDR(nbd_index_idr); static DEFINE_MUTEX(nbd_index_mutex); +static int nbd_total_devices = 0; struct nbd_sock { struct socket *sock; @@ -130,6 +131,7 @@ static int nbd_dev_dbg_init(struct nbd_device *nbd); static void nbd_dev_dbg_close(struct nbd_device *nbd); static void nbd_config_put(struct nbd_device *nbd); static void nbd_connect_reply(struct genl_info *info, int index); +static int nbd_genl_status(struct sk_buff *skb, struct genl_info *info); static void nbd_dead_link_work(struct work_struct *work); static inline struct device *nbd_to_dev(struct nbd_device *nbd) @@ -1457,6 +1459,7 @@ static int nbd_dev_add(int index) sprintf(disk->disk_name, "nbd%d", index); nbd_reset(nbd); add_disk(disk); + nbd_total_devices++; return index; out_free_tags: @@ -1493,12 +1496,22 @@ static struct nla_policy nbd_attr_policy[NBD_ATTR_MAX + 1] = { [NBD_ATTR_CLIENT_FLAGS] = { .type = NLA_U64 }, [NBD_ATTR_SOCKETS] = { .type = NLA_NESTED}, [NBD_ATTR_DEAD_CONN_TIMEOUT] = { .type = NLA_U64 }, + [NBD_ATTR_DEVICE_LIST] = { .type = NLA_NESTED}, }; static struct nla_policy nbd_sock_policy[NBD_SOCK_MAX + 1] = { [NBD_SOCK_FD] = { .type = NLA_U32 }, }; +/* We don't use this right now since we don't parse the incoming list, but we + * still want it here so userspace knows what to expect. + */ +static struct nla_policy __attribute__((unused)) +nbd_device_policy[NBD_DEVICE_ATTR_MAX + 1] = { + [NBD_DEVICE_INDEX] = { .type = NLA_U32 }, + [NBD_DEVICE_CONNECTED] = { .type = NLA_U8 }, +}; + static int nbd_genl_connect(struct sk_buff *skb, struct genl_info *info) { struct nbd_device *nbd = NULL; @@ -1764,6 +1777,11 @@ static const struct genl_ops nbd_connect_genl_ops[] = { .policy = nbd_attr_policy, .doit = nbd_genl_reconfigure, }, + { + .cmd = NBD_CMD_STATUS, + .policy = nbd_attr_policy, + .doit = nbd_genl_status, + }, }; static const struct genl_multicast_group nbd_mcast_grps[] = { @@ -1782,6 +1800,96 @@ static struct genl_family nbd_genl_family __ro_after_init = { .n_mcgrps = ARRAY_SIZE(nbd_mcast_grps), }; +static int populate_nbd_status(struct nbd_device *nbd, struct sk_buff *reply) +{ + struct nlattr *dev_opt; + u8 connected = 0; + int ret; + + /* This is a little racey, but for status it's ok. The + * reason we don't take a ref here is because we can't + * take a ref in the index == -1 case as we would need + * to put under the nbd_index_mutex, which could + * deadlock if we are configured to remove ourselves + * once we're disconnected. + */ + if (refcount_read(&nbd->config_refs)) + connected = 1; + dev_opt = nla_nest_start(reply, NBD_DEVICE_ITEM); + if (!dev_opt) + return -EMSGSIZE; + ret = nla_put_u32(reply, NBD_DEVICE_INDEX, nbd->index); + if (ret) + return -EMSGSIZE; + ret = nla_put_u8(reply, NBD_DEVICE_CONNECTED, + connected); + if (ret) + return -EMSGSIZE; + nla_nest_end(reply, dev_opt); + return 0; +} + +static int status_cb(int id, void *ptr, void *data) +{ + struct nbd_device *nbd = ptr; + return populate_nbd_status(nbd, (struct sk_buff *)data); +} + +static int nbd_genl_status(struct sk_buff *skb, struct genl_info *info) +{ + struct nlattr *dev_list; + struct sk_buff *reply; + void *reply_head; + size_t msg_size; + int index = -1; + int ret = -ENOMEM; + + if (info->attrs[NBD_ATTR_INDEX]) + index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]); + + mutex_lock(&nbd_index_mutex); + + msg_size = nla_total_size(nla_attr_size(sizeof(u32)) + + nla_attr_size(sizeof(u8))); + msg_size *= (index == -1) ? nbd_total_devices : 1; + + reply = genlmsg_new(msg_size, GFP_KERNEL); + if (!reply) + goto out; + reply_head = genlmsg_put_reply(reply, info, &nbd_genl_family, 0, + NBD_CMD_STATUS); + if (!reply_head) { + nlmsg_free(reply); + goto out; + } + + dev_list = nla_nest_start(reply, NBD_ATTR_DEVICE_LIST); + if (index == -1) { + ret = idr_for_each(&nbd_index_idr, &status_cb, reply); + if (ret) { + nlmsg_free(reply); + goto out; + } + } else { + struct nbd_device *nbd; + nbd = idr_find(&nbd_index_idr, index); + if (nbd) { + ret = populate_nbd_status(nbd, reply); + if (ret) { + nlmsg_free(reply); + goto out; + } + } + } + nla_nest_end(reply, dev_list); + genlmsg_end(reply, reply_head); + genlmsg_reply(reply, info); + ret = 0; +out: + mutex_unlock(&nbd_index_mutex); + return ret; +} + static void nbd_connect_reply(struct genl_info *info, int index) { struct sk_buff *skb; |