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	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
    drbd_nl.c
 
    This file is part of DRBD by Philipp Reisner and Lars Ellenberg.
 
    Copyright (C) 2001-2008, LINBIT Information Technologies GmbH.
    Copyright (C) 1999-2008, Philipp Reisner <philipp.reisner@linbit.com>.
    Copyright (C) 2002-2008, Lars Ellenberg <lars.ellenberg@linbit.com>.
 
 
  */
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
 #include <linux/module.h>
 #include <linux/drbd.h>
 #include <linux/in.h>
 #include <linux/fs.h>
 #include <linux/file.h>
 #include <linux/slab.h>
 #include <linux/blkpg.h>
 #include <linux/cpumask.h>
 #include "drbd_int.h"
 #include "drbd_protocol.h"
 #include "drbd_req.h"
 #include "drbd_state_change.h"
 #include <asm/unaligned.h>
 #include <linux/drbd_limits.h>
 #include <linux/kthread.h>
 
 #include <net/genetlink.h>
 
 /* .doit */
 // int drbd_adm_create_resource(struct sk_buff *skb, struct genl_info *info);
 // int drbd_adm_delete_resource(struct sk_buff *skb, struct genl_info *info);
 
 int drbd_adm_new_minor(struct sk_buff *skb, struct genl_info *info);
 int drbd_adm_del_minor(struct sk_buff *skb, struct genl_info *info);
 
 int drbd_adm_new_resource(struct sk_buff *skb, struct genl_info *info);
 int drbd_adm_del_resource(struct sk_buff *skb, struct genl_info *info);
 int drbd_adm_down(struct sk_buff *skb, struct genl_info *info);
 
 int drbd_adm_set_role(struct sk_buff *skb, struct genl_info *info);
 int drbd_adm_attach(struct sk_buff *skb, struct genl_info *info);
 int drbd_adm_disk_opts(struct sk_buff *skb, struct genl_info *info);
 int drbd_adm_detach(struct sk_buff *skb, struct genl_info *info);
 int drbd_adm_connect(struct sk_buff *skb, struct genl_info *info);
 int drbd_adm_net_opts(struct sk_buff *skb, struct genl_info *info);
 int drbd_adm_resize(struct sk_buff *skb, struct genl_info *info);
 int drbd_adm_start_ov(struct sk_buff *skb, struct genl_info *info);
 int drbd_adm_new_c_uuid(struct sk_buff *skb, struct genl_info *info);
 int drbd_adm_disconnect(struct sk_buff *skb, struct genl_info *info);
 int drbd_adm_invalidate(struct sk_buff *skb, struct genl_info *info);
 int drbd_adm_invalidate_peer(struct sk_buff *skb, struct genl_info *info);
 int drbd_adm_pause_sync(struct sk_buff *skb, struct genl_info *info);
 int drbd_adm_resume_sync(struct sk_buff *skb, struct genl_info *info);
 int drbd_adm_suspend_io(struct sk_buff *skb, struct genl_info *info);
 int drbd_adm_resume_io(struct sk_buff *skb, struct genl_info *info);
 int drbd_adm_outdate(struct sk_buff *skb, struct genl_info *info);
 int drbd_adm_resource_opts(struct sk_buff *skb, struct genl_info *info);
 int drbd_adm_get_status(struct sk_buff *skb, struct genl_info *info);
 int drbd_adm_get_timeout_type(struct sk_buff *skb, struct genl_info *info);
 /* .dumpit */
 int drbd_adm_get_status_all(struct sk_buff *skb, struct netlink_callback *cb);
 int drbd_adm_dump_resources(struct sk_buff *skb, struct netlink_callback *cb);
 int drbd_adm_dump_devices(struct sk_buff *skb, struct netlink_callback *cb);
 int drbd_adm_dump_devices_done(struct netlink_callback *cb);
 int drbd_adm_dump_connections(struct sk_buff *skb, struct netlink_callback *cb);
 int drbd_adm_dump_connections_done(struct netlink_callback *cb);
 int drbd_adm_dump_peer_devices(struct sk_buff *skb, struct netlink_callback *cb);
 int drbd_adm_dump_peer_devices_done(struct netlink_callback *cb);
 int drbd_adm_get_initial_state(struct sk_buff *skb, struct netlink_callback *cb);
 
 #include <linux/drbd_genl_api.h>
 #include "drbd_nla.h"
 #include <linux/genl_magic_func.h>
 
 static atomic_t drbd_genl_seq = ATOMIC_INIT(2); /* two. */
 static atomic_t notify_genl_seq = ATOMIC_INIT(2); /* two. */
 
 DEFINE_MUTEX(notification_mutex);
 
 /* used blkdev_get_by_path, to claim our meta data device(s) */
 static char *drbd_m_holder = "Hands off! this is DRBD's meta data device.";
 
 static void drbd_adm_send_reply(struct sk_buff *skb, struct genl_info *info)
 {
     genlmsg_end(skb, genlmsg_data(nlmsg_data(nlmsg_hdr(skb))));
     if (genlmsg_reply(skb, info))
         pr_err("error sending genl reply\n");
 }
 
 /* Used on a fresh "drbd_adm_prepare"d reply_skb, this cannot fail: The only
  * reason it could fail was no space in skb, and there are 4k available. */
 static int drbd_msg_put_info(struct sk_buff *skb, const char *info)
 {
     struct nlattr *nla;
     int err = -EMSGSIZE;
 
     if (!info || !info[0])
         return 0;
 
     nla = nla_nest_start_noflag(skb, DRBD_NLA_CFG_REPLY);
     if (!nla)
         return err;
 
     err = nla_put_string(skb, T_info_text, info);
     if (err) {
         nla_nest_cancel(skb, nla);
         return err;
     } else
         nla_nest_end(skb, nla);
     return 0;
 }
 
 __printf(2, 3)
 static int drbd_msg_sprintf_info(struct sk_buff *skb, const char *fmt, ...)
 {
     va_list args;
     struct nlattr *nla, *txt;
     int err = -EMSGSIZE;
     int len;
 
     nla = nla_nest_start_noflag(skb, DRBD_NLA_CFG_REPLY);
     if (!nla)
         return err;
 
     txt = nla_reserve(skb, T_info_text, 256);
     if (!txt) {
         nla_nest_cancel(skb, nla);
         return err;
     }
     va_start(args, fmt);
     len = vscnprintf(nla_data(txt), 256, fmt, args);
     va_end(args);
 
     /* maybe: retry with larger reserve, if truncated */
     txt->nla_len = nla_attr_size(len+1);
     nlmsg_trim(skb, (char*)txt + NLA_ALIGN(txt->nla_len));
     nla_nest_end(skb, nla);
 
     return 0;
 }
 
 /* This would be a good candidate for a "pre_doit" hook,
  * and per-family private info->pointers.
  * But we need to stay compatible with older kernels.
  * If it returns successfully, adm_ctx members are valid.
  *
  * At this point, we still rely on the global genl_lock().
  * If we want to avoid that, and allow "genl_family.parallel_ops", we may need
  * to add additional synchronization against object destruction/modification.
  */
 #define DRBD_ADM_NEED_MINOR 1
 #define DRBD_ADM_NEED_RESOURCE  2
 #define DRBD_ADM_NEED_CONNECTION 4
 static int drbd_adm_prepare(struct drbd_config_context *adm_ctx,
     struct sk_buff *skb, struct genl_info *info, unsigned flags)
 {
     struct drbd_genlmsghdr *d_in = info->userhdr;
     const u8 cmd = info->genlhdr->cmd;
     int err;
 
     memset(adm_ctx, 0, sizeof(*adm_ctx));
 
     /* genl_rcv_msg only checks for CAP_NET_ADMIN on "GENL_ADMIN_PERM" :( */
     if (cmd != DRBD_ADM_GET_STATUS && !capable(CAP_NET_ADMIN))
            return -EPERM;
 
     adm_ctx->reply_skb = genlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
     if (!adm_ctx->reply_skb) {
         err = -ENOMEM;
         goto fail;
     }
 
     adm_ctx->reply_dh = genlmsg_put_reply(adm_ctx->reply_skb,
                     info, &drbd_genl_family, 0, cmd);
     /* put of a few bytes into a fresh skb of >= 4k will always succeed.
      * but anyways */
     if (!adm_ctx->reply_dh) {
         err = -ENOMEM;
         goto fail;
     }
 
     adm_ctx->reply_dh->minor = d_in->minor;
     adm_ctx->reply_dh->ret_code = NO_ERROR;
 
     adm_ctx->volume = VOLUME_UNSPECIFIED;
     if (info->attrs[DRBD_NLA_CFG_CONTEXT]) {
         struct nlattr *nla;
         /* parse and validate only */
         err = drbd_cfg_context_from_attrs(NULL, info);
         if (err)
             goto fail;
 
         /* It was present, and valid,
          * copy it over to the reply skb. */
         err = nla_put_nohdr(adm_ctx->reply_skb,
                 info->attrs[DRBD_NLA_CFG_CONTEXT]->nla_len,
                 info->attrs[DRBD_NLA_CFG_CONTEXT]);
         if (err)
             goto fail;
 
         /* and assign stuff to the adm_ctx */
         nla = nested_attr_tb[__nla_type(T_ctx_volume)];
         if (nla)
             adm_ctx->volume = nla_get_u32(nla);
         nla = nested_attr_tb[__nla_type(T_ctx_resource_name)];
         if (nla)
             adm_ctx->resource_name = nla_data(nla);
         adm_ctx->my_addr = nested_attr_tb[__nla_type(T_ctx_my_addr)];
         adm_ctx->peer_addr = nested_attr_tb[__nla_type(T_ctx_peer_addr)];
         if ((adm_ctx->my_addr &&
              nla_len(adm_ctx->my_addr) > sizeof(adm_ctx->connection->my_addr)) ||
             (adm_ctx->peer_addr &&
              nla_len(adm_ctx->peer_addr) > sizeof(adm_ctx->connection->peer_addr))) {
             err = -EINVAL;
             goto fail;
         }
     }
 
     adm_ctx->minor = d_in->minor;
     adm_ctx->device = minor_to_device(d_in->minor);
 
     /* We are protected by the global genl_lock().
      * But we may explicitly drop it/retake it in drbd_adm_set_role(),
      * so make sure this object stays around. */
     if (adm_ctx->device)
         kref_get(&adm_ctx->device->kref);
 
     if (adm_ctx->resource_name) {
         adm_ctx->resource = drbd_find_resource(adm_ctx->resource_name);
     }
 
     if (!adm_ctx->device && (flags & DRBD_ADM_NEED_MINOR)) {
         drbd_msg_put_info(adm_ctx->reply_skb, "unknown minor");
         return ERR_MINOR_INVALID;
     }
     if (!adm_ctx->resource && (flags & DRBD_ADM_NEED_RESOURCE)) {
         drbd_msg_put_info(adm_ctx->reply_skb, "unknown resource");
         if (adm_ctx->resource_name)
             return ERR_RES_NOT_KNOWN;
         return ERR_INVALID_REQUEST;
     }
 
     if (flags & DRBD_ADM_NEED_CONNECTION) {
         if (adm_ctx->resource) {
             drbd_msg_put_info(adm_ctx->reply_skb, "no resource name expected");
             return ERR_INVALID_REQUEST;
         }
         if (adm_ctx->device) {
             drbd_msg_put_info(adm_ctx->reply_skb, "no minor number expected");
             return ERR_INVALID_REQUEST;
         }
         if (adm_ctx->my_addr && adm_ctx->peer_addr)
             adm_ctx->connection = conn_get_by_addrs(nla_data(adm_ctx->my_addr),
                               nla_len(adm_ctx->my_addr),
                               nla_data(adm_ctx->peer_addr),
                               nla_len(adm_ctx->peer_addr));
         if (!adm_ctx->connection) {
             drbd_msg_put_info(adm_ctx->reply_skb, "unknown connection");
             return ERR_INVALID_REQUEST;
         }
     }
 
     /* some more paranoia, if the request was over-determined */
     if (adm_ctx->device && adm_ctx->resource &&
         adm_ctx->device->resource != adm_ctx->resource) {
         pr_warn("request: minor=%u, resource=%s; but that minor belongs to resource %s\n",
             adm_ctx->minor, adm_ctx->resource->name,
             adm_ctx->device->resource->name);
         drbd_msg_put_info(adm_ctx->reply_skb, "minor exists in different resource");
         return ERR_INVALID_REQUEST;
     }
     if (adm_ctx->device &&
         adm_ctx->volume != VOLUME_UNSPECIFIED &&
         adm_ctx->volume != adm_ctx->device->vnr) {
         pr_warn("request: minor=%u, volume=%u; but that minor is volume %u in %s\n",
             adm_ctx->minor, adm_ctx->volume,
             adm_ctx->device->vnr, adm_ctx->device->resource->name);
         drbd_msg_put_info(adm_ctx->reply_skb, "minor exists as different volume");
         return ERR_INVALID_REQUEST;
     }
 
     /* still, provide adm_ctx->resource always, if possible. */
     if (!adm_ctx->resource) {
         adm_ctx->resource = adm_ctx->device ? adm_ctx->device->resource
             : adm_ctx->connection ? adm_ctx->connection->resource : NULL;
         if (adm_ctx->resource)
             kref_get(&adm_ctx->resource->kref);
     }
 
     return NO_ERROR;
 
 fail:
     nlmsg_free(adm_ctx->reply_skb);
     adm_ctx->reply_skb = NULL;
     return err;
 }
 
 static int drbd_adm_finish(struct drbd_config_context *adm_ctx,
     struct genl_info *info, int retcode)
 {
     if (adm_ctx->device) {
         kref_put(&adm_ctx->device->kref, drbd_destroy_device);
         adm_ctx->device = NULL;
     }
     if (adm_ctx->connection) {
         kref_put(&adm_ctx->connection->kref, &drbd_destroy_connection);
         adm_ctx->connection = NULL;
     }
     if (adm_ctx->resource) {
         kref_put(&adm_ctx->resource->kref, drbd_destroy_resource);
         adm_ctx->resource = NULL;
     }
 
     if (!adm_ctx->reply_skb)
         return -ENOMEM;
 
     adm_ctx->reply_dh->ret_code = retcode;
     drbd_adm_send_reply(adm_ctx->reply_skb, info);
     return 0;
 }
 
 static void setup_khelper_env(struct drbd_connection *connection, char **envp)
 {
     char *afs;
 
     /* FIXME: A future version will not allow this case. */
     if (connection->my_addr_len == 0 || connection->peer_addr_len == 0)
         return;
 
     switch (((struct sockaddr *)&connection->peer_addr)->sa_family) {
     case AF_INET6:
         afs = "ipv6";
         snprintf(envp[4], 60, "DRBD_PEER_ADDRESS=%pI6",
              &((struct sockaddr_in6 *)&connection->peer_addr)->sin6_addr);
         break;
     case AF_INET:
         afs = "ipv4";
         snprintf(envp[4], 60, "DRBD_PEER_ADDRESS=%pI4",
              &((struct sockaddr_in *)&connection->peer_addr)->sin_addr);
         break;
     default:
         afs = "ssocks";
         snprintf(envp[4], 60, "DRBD_PEER_ADDRESS=%pI4",
              &((struct sockaddr_in *)&connection->peer_addr)->sin_addr);
     }
     snprintf(envp[3], 20, "DRBD_PEER_AF=%s", afs);
 }
 
 int drbd_khelper(struct drbd_device *device, char *cmd)
 {
     char *envp[] = { "HOME=/",
             "TERM=linux",
             "PATH=/sbin:/usr/sbin:/bin:/usr/bin",
              (char[20]) { }, /* address family */
              (char[60]) { }, /* address */
             NULL };
     char mb[14];
     char *argv[] = {drbd_usermode_helper, cmd, mb, NULL };
     struct drbd_connection *connection = first_peer_device(device)->connection;
     struct sib_info sib;
     int ret;
 
     if (current == connection->worker.task)
         set_bit(CALLBACK_PENDING, &connection->flags);
 
     snprintf(mb, 14, "minor-%d", device_to_minor(device));
     setup_khelper_env(connection, envp);
 
     /* The helper may take some time.
      * write out any unsynced meta data changes now */
     drbd_md_sync(device);
 
     drbd_info(device, "helper command: %s %s %s\n", drbd_usermode_helper, cmd, mb);
     sib.sib_reason = SIB_HELPER_PRE;
     sib.helper_name = cmd;
     drbd_bcast_event(device, &sib);
     notify_helper(NOTIFY_CALL, device, connection, cmd, 0);
     ret = call_usermodehelper(drbd_usermode_helper, argv, envp, UMH_WAIT_PROC);
     if (ret)
         drbd_warn(device, "helper command: %s %s %s exit code %u (0x%x)\n",
                 drbd_usermode_helper, cmd, mb,
                 (ret >> 8) & 0xff, ret);
     else
         drbd_info(device, "helper command: %s %s %s exit code %u (0x%x)\n",
                 drbd_usermode_helper, cmd, mb,
                 (ret >> 8) & 0xff, ret);
     sib.sib_reason = SIB_HELPER_POST;
     sib.helper_exit_code = ret;
     drbd_bcast_event(device, &sib);
     notify_helper(NOTIFY_RESPONSE, device, connection, cmd, ret);
 
     if (current == connection->worker.task)
         clear_bit(CALLBACK_PENDING, &connection->flags);
 
     if (ret < 0) /* Ignore any ERRNOs we got. */
         ret = 0;
 
     return ret;
 }
 
 enum drbd_peer_state conn_khelper(struct drbd_connection *connection, char *cmd)
 {
     char *envp[] = { "HOME=/",
             "TERM=linux",
             "PATH=/sbin:/usr/sbin:/bin:/usr/bin",
              (char[20]) { }, /* address family */
              (char[60]) { }, /* address */
             NULL };
     char *resource_name = connection->resource->name;
     char *argv[] = {drbd_usermode_helper, cmd, resource_name, NULL };
     int ret;
 
     setup_khelper_env(connection, envp);
     conn_md_sync(connection);
 
     drbd_info(connection, "helper command: %s %s %s\n", drbd_usermode_helper, cmd, resource_name);
     /* TODO: conn_bcast_event() ?? */
     notify_helper(NOTIFY_CALL, NULL, connection, cmd, 0);
 
     ret = call_usermodehelper(drbd_usermode_helper, argv, envp, UMH_WAIT_PROC);
     if (ret)
         drbd_warn(connection, "helper command: %s %s %s exit code %u (0x%x)\n",
               drbd_usermode_helper, cmd, resource_name,
               (ret >> 8) & 0xff, ret);
     else
         drbd_info(connection, "helper command: %s %s %s exit code %u (0x%x)\n",
               drbd_usermode_helper, cmd, resource_name,
               (ret >> 8) & 0xff, ret);
     /* TODO: conn_bcast_event() ?? */
     notify_helper(NOTIFY_RESPONSE, NULL, connection, cmd, ret);
 
     if (ret < 0) /* Ignore any ERRNOs we got. */
         ret = 0;
 
     return ret;
 }
 
 static enum drbd_fencing_p highest_fencing_policy(struct drbd_connection *connection)
 {
     enum drbd_fencing_p fp = FP_NOT_AVAIL;
     struct drbd_peer_device *peer_device;
     int vnr;
 
     rcu_read_lock();
     idr_for_each_entry(&connection->peer_devices, peer_device, vnr) {
         struct drbd_device *device = peer_device->device;
         if (get_ldev_if_state(device, D_CONSISTENT)) {
             struct disk_conf *disk_conf =
                 rcu_dereference(peer_device->device->ldev->disk_conf);
             fp = max_t(enum drbd_fencing_p, fp, disk_conf->fencing);
             put_ldev(device);
         }
     }
     rcu_read_unlock();
 
     return fp;
 }
 
 static bool resource_is_supended(struct drbd_resource *resource)
 {
     return resource->susp || resource->susp_fen || resource->susp_nod;
 }
 
 bool conn_try_outdate_peer(struct drbd_connection *connection)
 {
     struct drbd_resource * const resource = connection->resource;
     unsigned int connect_cnt;
     union drbd_state mask = { };
     union drbd_state val = { };
     enum drbd_fencing_p fp;
     char *ex_to_string;
     int r;
 
     spin_lock_irq(&resource->req_lock);
     if (connection->cstate >= C_WF_REPORT_PARAMS) {
         drbd_err(connection, "Expected cstate < C_WF_REPORT_PARAMS\n");
         spin_unlock_irq(&resource->req_lock);
         return false;
     }
 
     connect_cnt = connection->connect_cnt;
     spin_unlock_irq(&resource->req_lock);
 
     fp = highest_fencing_policy(connection);
     switch (fp) {
     case FP_NOT_AVAIL:
         drbd_warn(connection, "Not fencing peer, I'm not even Consistent myself.\n");
         spin_lock_irq(&resource->req_lock);
         if (connection->cstate < C_WF_REPORT_PARAMS) {
             _conn_request_state(connection,
                         (union drbd_state) { { .susp_fen = 1 } },
                         (union drbd_state) { { .susp_fen = 0 } },
                         CS_VERBOSE | CS_HARD | CS_DC_SUSP);
             /* We are no longer suspended due to the fencing policy.
              * We may still be suspended due to the on-no-data-accessible policy.
              * If that was OND_IO_ERROR, fail pending requests. */
             if (!resource_is_supended(resource))
                 _tl_restart(connection, CONNECTION_LOST_WHILE_PENDING);
         }
         /* Else: in case we raced with a connection handshake,
          * let the handshake figure out if we maybe can RESEND,
          * and do not resume/fail pending requests here.
          * Worst case is we stay suspended for now, which may be
          * resolved by either re-establishing the replication link, or
          * the next link failure, or eventually the administrator.  */
         spin_unlock_irq(&resource->req_lock);
         return false;
 
     case FP_DONT_CARE:
         return true;
     default: ;
     }
 
     r = conn_khelper(connection, "fence-peer");
 
     switch ((r>>8) & 0xff) {
     case P_INCONSISTENT: /* peer is inconsistent */
         ex_to_string = "peer is inconsistent or worse";
         mask.pdsk = D_MASK;
         val.pdsk = D_INCONSISTENT;
         break;
     case P_OUTDATED: /* peer got outdated, or was already outdated */
         ex_to_string = "peer was fenced";
         mask.pdsk = D_MASK;
         val.pdsk = D_OUTDATED;
         break;
     case P_DOWN: /* peer was down */
         if (conn_highest_disk(connection) == D_UP_TO_DATE) {
             /* we will(have) create(d) a new UUID anyways... */
             ex_to_string = "peer is unreachable, assumed to be dead";
             mask.pdsk = D_MASK;
             val.pdsk = D_OUTDATED;
         } else {
             ex_to_string = "peer unreachable, doing nothing since disk != UpToDate";
         }
         break;
     case P_PRIMARY: /* Peer is primary, voluntarily outdate myself.
          * This is useful when an unconnected R_SECONDARY is asked to
          * become R_PRIMARY, but finds the other peer being active. */
         ex_to_string = "peer is active";
         drbd_warn(connection, "Peer is primary, outdating myself.\n");
         mask.disk = D_MASK;
         val.disk = D_OUTDATED;
         break;
     case P_FENCING:
         /* THINK: do we need to handle this
          * like case 4, or more like case 5? */
         if (fp != FP_STONITH)
             drbd_err(connection, "fence-peer() = 7 && fencing != Stonith !!!\n");
         ex_to_string = "peer was stonithed";
         mask.pdsk = D_MASK;
         val.pdsk = D_OUTDATED;
         break;
     default:
         /* The script is broken ... */
         drbd_err(connection, "fence-peer helper broken, returned %d\n", (r>>8)&0xff);
         return false; /* Eventually leave IO frozen */
     }
 
     drbd_info(connection, "fence-peer helper returned %d (%s)\n",
           (r>>8) & 0xff, ex_to_string);
 
     /* Not using
        conn_request_state(connection, mask, val, CS_VERBOSE);
        here, because we might were able to re-establish the connection in the
        meantime. */
     spin_lock_irq(&resource->req_lock);
     if (connection->cstate < C_WF_REPORT_PARAMS && !test_bit(STATE_SENT, &connection->flags)) {
         if (connection->connect_cnt != connect_cnt)
             /* In case the connection was established and droped
                while the fence-peer handler was running, ignore it */
             drbd_info(connection, "Ignoring fence-peer exit code\n");
         else
             _conn_request_state(connection, mask, val, CS_VERBOSE);
     }
     spin_unlock_irq(&resource->req_lock);
 
     return conn_highest_pdsk(connection) <= D_OUTDATED;
 }
 
 static int _try_outdate_peer_async(void *data)
 {
     struct drbd_connection *connection = (struct drbd_connection *)data;
 
     conn_try_outdate_peer(connection);
 
     kref_put(&connection->kref, drbd_destroy_connection);
     return 0;
 }
 
 void conn_try_outdate_peer_async(struct drbd_connection *connection)
 {
     struct task_struct *opa;
 
     kref_get(&connection->kref);
     /* We may have just sent a signal to this thread
      * to get it out of some blocking network function.
      * Clear signals; otherwise kthread_run(), which internally uses
      * wait_on_completion_killable(), will mistake our pending signal
      * for a new fatal signal and fail. */
     flush_signals(current);
     opa = kthread_run(_try_outdate_peer_async, connection, "drbd_async_h");
     if (IS_ERR(opa)) {
         drbd_err(connection, "out of mem, failed to invoke fence-peer helper\n");
         kref_put(&connection->kref, drbd_destroy_connection);
     }
 }
 
 enum drbd_state_rv
 drbd_set_role(struct drbd_device *const device, enum drbd_role new_role, int force)
 {
     struct drbd_peer_device *const peer_device = first_peer_device(device);
     struct drbd_connection *const connection = peer_device ? peer_device->connection : NULL;
     const int max_tries = 4;
     enum drbd_state_rv rv = SS_UNKNOWN_ERROR;
     struct net_conf *nc;
     int try = 0;
     int forced = 0;
     union drbd_state mask, val;
 
     if (new_role == R_PRIMARY) {
         struct drbd_connection *connection;
 
         /* Detect dead peers as soon as possible.  */
 
         rcu_read_lock();
         for_each_connection(connection, device->resource)
             request_ping(connection);
         rcu_read_unlock();
     }
 
     mutex_lock(device->state_mutex);
 
     mask.i = 0; mask.role = R_MASK;
     val.i  = 0; val.role  = new_role;
 
     while (try++ < max_tries) {
         rv = _drbd_request_state_holding_state_mutex(device, mask, val, CS_WAIT_COMPLETE);
 
         /* in case we first succeeded to outdate,
          * but now suddenly could establish a connection */
         if (rv == SS_CW_FAILED_BY_PEER && mask.pdsk != 0) {
             val.pdsk = 0;
             mask.pdsk = 0;
             continue;
         }
 
         if (rv == SS_NO_UP_TO_DATE_DISK && force &&
             (device->state.disk < D_UP_TO_DATE &&
              device->state.disk >= D_INCONSISTENT)) {
             mask.disk = D_MASK;
             val.disk  = D_UP_TO_DATE;
             forced = 1;
             continue;
         }
 
         if (rv == SS_NO_UP_TO_DATE_DISK &&
             device->state.disk == D_CONSISTENT && mask.pdsk == 0) {
             D_ASSERT(device, device->state.pdsk == D_UNKNOWN);
 
             if (conn_try_outdate_peer(connection)) {
                 val.disk = D_UP_TO_DATE;
                 mask.disk = D_MASK;
             }
             continue;
         }
 
         if (rv == SS_NOTHING_TO_DO)
             goto out;
         if (rv == SS_PRIMARY_NOP && mask.pdsk == 0) {
             if (!conn_try_outdate_peer(connection) && force) {
                 drbd_warn(device, "Forced into split brain situation!\n");
                 mask.pdsk = D_MASK;
                 val.pdsk  = D_OUTDATED;
 
             }
             continue;
         }
         if (rv == SS_TWO_PRIMARIES) {
             /* Maybe the peer is detected as dead very soon...
                retry at most once more in this case. */
             if (try < max_tries) {
                 int timeo;
                 try = max_tries - 1;
                 rcu_read_lock();
                 nc = rcu_dereference(connection->net_conf);
                 timeo = nc ? (nc->ping_timeo + 1) * HZ / 10 : 1;
                 rcu_read_unlock();
                 schedule_timeout_interruptible(timeo);
             }
             continue;
         }
         if (rv < SS_SUCCESS) {
             rv = _drbd_request_state(device, mask, val,
                         CS_VERBOSE + CS_WAIT_COMPLETE);
             if (rv < SS_SUCCESS)
                 goto out;
         }
         break;
     }
 
     if (rv < SS_SUCCESS)
         goto out;
 
     if (forced)
         drbd_warn(device, "Forced to consider local data as UpToDate!\n");
 
     /* Wait until nothing is on the fly :) */
     wait_event(device->misc_wait, atomic_read(&device->ap_pending_cnt) == 0);
 
     /* FIXME also wait for all pending P_BARRIER_ACK? */
 
     if (new_role == R_SECONDARY) {
         if (get_ldev(device)) {
             device->ldev->md.uuid[UI_CURRENT] &= ~(u64)1;
             put_ldev(device);
         }
     } else {
         mutex_lock(&device->resource->conf_update);
         nc = connection->net_conf;
         if (nc)
             nc->discard_my_data = 0; /* without copy; single bit op is atomic */
         mutex_unlock(&device->resource->conf_update);
 
         if (get_ldev(device)) {
             if (((device->state.conn < C_CONNECTED ||
                    device->state.pdsk <= D_FAILED)
                   && device->ldev->md.uuid[UI_BITMAP] == 0) || forced)
                 drbd_uuid_new_current(device);
 
             device->ldev->md.uuid[UI_CURRENT] |=  (u64)1;
             put_ldev(device);
         }
     }
 
     /* writeout of activity log covered areas of the bitmap
      * to stable storage done in after state change already */
 
     if (device->state.conn >= C_WF_REPORT_PARAMS) {
         /* if this was forced, we should consider sync */
         if (forced)
             drbd_send_uuids(peer_device);
         drbd_send_current_state(peer_device);
     }
 
     drbd_md_sync(device);
     set_disk_ro(device->vdisk, new_role == R_SECONDARY);
     kobject_uevent(&disk_to_dev(device->vdisk)->kobj, KOBJ_CHANGE);
 out:
     mutex_unlock(device->state_mutex);
     return rv;
 }
 
 static const char *from_attrs_err_to_txt(int err)
 {
     return  err == -ENOMSG ? "required attribute missing" :
         err == -EOPNOTSUPP ? "unknown mandatory attribute" :
         err == -EEXIST ? "can not change invariant setting" :
         "invalid attribute value";
 }
 
 int drbd_adm_set_role(struct sk_buff *skb, struct genl_info *info)
 {
     struct drbd_config_context adm_ctx;
     struct set_role_parms parms;
     int err;
     enum drbd_ret_code retcode;
     enum drbd_state_rv rv;
 
     retcode = drbd_adm_prepare(&adm_ctx, skb, info, DRBD_ADM_NEED_MINOR);
     if (!adm_ctx.reply_skb)
         return retcode;
     if (retcode != NO_ERROR)
         goto out;
 
     memset(&parms, 0, sizeof(parms));
     if (info->attrs[DRBD_NLA_SET_ROLE_PARMS]) {
         err = set_role_parms_from_attrs(&parms, info);
         if (err) {
             retcode = ERR_MANDATORY_TAG;
             drbd_msg_put_info(adm_ctx.reply_skb, from_attrs_err_to_txt(err));
             goto out;
         }
     }
     genl_unlock();
     mutex_lock(&adm_ctx.resource->adm_mutex);
 
     if (info->genlhdr->cmd == DRBD_ADM_PRIMARY)
         rv = drbd_set_role(adm_ctx.device, R_PRIMARY, parms.assume_uptodate);
     else
         rv = drbd_set_role(adm_ctx.device, R_SECONDARY, 0);
 
     mutex_unlock(&adm_ctx.resource->adm_mutex);
     genl_lock();
     drbd_adm_finish(&adm_ctx, info, rv);
     return 0;
 out:
     drbd_adm_finish(&adm_ctx, info, retcode);
     return 0;
 }
 
 /* Initializes the md.*_offset members, so we are able to find
  * the on disk meta data.
  *
  * We currently have two possible layouts:
  * external:
  *   |----------- md_size_sect ------------------|
  *   [ 4k superblock ][ activity log ][  Bitmap  ]
  *   | al_offset == 8 |
  *   | bm_offset = al_offset + X      |
  *  ==> bitmap sectors = md_size_sect - bm_offset
  *
  * internal:
  *            |----------- md_size_sect ------------------|
  * [data.....][  Bitmap  ][ activity log ][ 4k superblock ]
  *                        | al_offset < 0 |
  *            | bm_offset = al_offset - Y |
  *  ==> bitmap sectors = Y = al_offset - bm_offset
  *
  *  Activity log size used to be fixed 32kB,
  *  but is about to become configurable.
  */
 static void drbd_md_set_sector_offsets(struct drbd_device *device,
                        struct drbd_backing_dev *bdev)
 {
     sector_t md_size_sect = 0;
     unsigned int al_size_sect = bdev->md.al_size_4k * 8;
 
     bdev->md.md_offset = drbd_md_ss(bdev);
 
     switch (bdev->md.meta_dev_idx) {
     default:
         /* v07 style fixed size indexed meta data */
         bdev->md.md_size_sect = MD_128MB_SECT;
         bdev->md.al_offset = MD_4kB_SECT;
         bdev->md.bm_offset = MD_4kB_SECT + al_size_sect;
         break;
     case DRBD_MD_INDEX_FLEX_EXT:
         /* just occupy the full device; unit: sectors */
         bdev->md.md_size_sect = drbd_get_capacity(bdev->md_bdev);
         bdev->md.al_offset = MD_4kB_SECT;
         bdev->md.bm_offset = MD_4kB_SECT + al_size_sect;
         break;
     case DRBD_MD_INDEX_INTERNAL:
     case DRBD_MD_INDEX_FLEX_INT:
         /* al size is still fixed */
         bdev->md.al_offset = -al_size_sect;
         /* we need (slightly less than) ~ this much bitmap sectors: */
         md_size_sect = drbd_get_capacity(bdev->backing_bdev);
         md_size_sect = ALIGN(md_size_sect, BM_SECT_PER_EXT);
         md_size_sect = BM_SECT_TO_EXT(md_size_sect);
         md_size_sect = ALIGN(md_size_sect, 8);
 
         /* plus the "drbd meta data super block",
          * and the activity log; */
         md_size_sect += MD_4kB_SECT + al_size_sect;
 
         bdev->md.md_size_sect = md_size_sect;
         /* bitmap offset is adjusted by 'super' block size */
         bdev->md.bm_offset   = -md_size_sect + MD_4kB_SECT;
         break;
     }
 }
 
 /* input size is expected to be in KB */
 char *ppsize(char *buf, unsigned long long size)
 {
     /* Needs 9 bytes at max including trailing NUL:
      * -1ULL ==> "16384 EB" */
     static char units[] = { 'K', 'M', 'G', 'T', 'P', 'E' };
     int base = 0;
     while (size >= 10000 && base < sizeof(units)-1) {
         /* shift + round */
         size = (size >> 10) + !!(size & (1<<9));
         base++;
     }
     sprintf(buf, "%u %cB", (unsigned)size, units[base]);
 
     return buf;
 }
 
 /* there is still a theoretical deadlock when called from receiver
  * on an D_INCONSISTENT R_PRIMARY:
  *  remote READ does inc_ap_bio, receiver would need to receive answer
  *  packet from remote to dec_ap_bio again.
  *  receiver receive_sizes(), comes here,
  *  waits for ap_bio_cnt == 0. -> deadlock.
  * but this cannot happen, actually, because:
  *  R_PRIMARY D_INCONSISTENT, and peer's disk is unreachable
  *  (not connected, or bad/no disk on peer):
  *  see drbd_fail_request_early, ap_bio_cnt is zero.
  *  R_PRIMARY D_INCONSISTENT, and C_SYNC_TARGET:
  *  peer may not initiate a resize.
  */
 /* Note these are not to be confused with
  * drbd_adm_suspend_io/drbd_adm_resume_io,
  * which are (sub) state changes triggered by admin (drbdsetup),
  * and can be long lived.
  * This changes an device->flag, is triggered by drbd internals,
  * and should be short-lived. */
 /* It needs to be a counter, since multiple threads might
    independently suspend and resume IO. */
 void drbd_suspend_io(struct drbd_device *device)
 {
     atomic_inc(&device->suspend_cnt);
     if (drbd_suspended(device))
         return;
     wait_event(device->misc_wait, !atomic_read(&device->ap_bio_cnt));
 }
 
 void drbd_resume_io(struct drbd_device *device)
 {
     if (atomic_dec_and_test(&device->suspend_cnt))
         wake_up(&device->misc_wait);
 }
 
 /*
  * drbd_determine_dev_size() -  Sets the right device size obeying all constraints
  * @device: DRBD device.
  *
  * Returns 0 on success, negative return values indicate errors.
  * You should call drbd_md_sync() after calling this function.
  */
 enum determine_dev_size
 drbd_determine_dev_size(struct drbd_device *device, enum dds_flags flags, struct resize_parms *rs) __must_hold(local)
 {
     struct md_offsets_and_sizes {
         u64 last_agreed_sect;
         u64 md_offset;
         s32 al_offset;
         s32 bm_offset;
         u32 md_size_sect;
 
         u32 al_stripes;
         u32 al_stripe_size_4k;
     } prev;
     sector_t u_size, size;
     struct drbd_md *md = &device->ldev->md;
     void *buffer;
 
     int md_moved, la_size_changed;
     enum determine_dev_size rv = DS_UNCHANGED;
 
     /* We may change the on-disk offsets of our meta data below.  Lock out
      * anything that may cause meta data IO, to avoid acting on incomplete
      * layout changes or scribbling over meta data that is in the process
      * of being moved.
      *
      * Move is not exactly correct, btw, currently we have all our meta
      * data in core memory, to "move" it we just write it all out, there
      * are no reads. */
     drbd_suspend_io(device);
     buffer = drbd_md_get_buffer(device, __func__); /* Lock meta-data IO */
     if (!buffer) {
         drbd_resume_io(device);
         return DS_ERROR;
     }
 
     /* remember current offset and sizes */
     prev.last_agreed_sect = md->la_size_sect;
     prev.md_offset = md->md_offset;
     prev.al_offset = md->al_offset;
     prev.bm_offset = md->bm_offset;
     prev.md_size_sect = md->md_size_sect;
     prev.al_stripes = md->al_stripes;
     prev.al_stripe_size_4k = md->al_stripe_size_4k;
 
     if (rs) {
         /* rs is non NULL if we should change the AL layout only */
         md->al_stripes = rs->al_stripes;
         md->al_stripe_size_4k = rs->al_stripe_size / 4;
         md->al_size_4k = (u64)rs->al_stripes * rs->al_stripe_size / 4;
     }
 
     drbd_md_set_sector_offsets(device, device->ldev);
 
     rcu_read_lock();
     u_size = rcu_dereference(device->ldev->disk_conf)->disk_size;
     rcu_read_unlock();
     size = drbd_new_dev_size(device, device->ldev, u_size, flags & DDSF_FORCED);
 
     if (size < prev.last_agreed_sect) {
         if (rs && u_size == 0) {
             /* Remove "rs &&" later. This check should always be active, but
                right now the receiver expects the permissive behavior */
             drbd_warn(device, "Implicit shrink not allowed. "
                  "Use --size=%llus for explicit shrink.\n",
                  (unsigned long long)size);
             rv = DS_ERROR_SHRINK;
         }
         if (u_size > size)
             rv = DS_ERROR_SPACE_MD;
         if (rv != DS_UNCHANGED)
             goto err_out;
     }
 
     if (get_capacity(device->vdisk) != size ||
         drbd_bm_capacity(device) != size) {
         int err;
         err = drbd_bm_resize(device, size, !(flags & DDSF_NO_RESYNC));
         if (unlikely(err)) {
             /* currently there is only one error: ENOMEM! */
             size = drbd_bm_capacity(device);
             if (size == 0) {
                 drbd_err(device, "OUT OF MEMORY! "
                     "Could not allocate bitmap!\n");
             } else {
                 drbd_err(device, "BM resizing failed. "
                     "Leaving size unchanged\n");
             }
             rv = DS_ERROR;
         }
         /* racy, see comments above. */
         drbd_set_my_capacity(device, size);
         md->la_size_sect = size;
     }
     if (rv <= DS_ERROR)
         goto err_out;
 
     la_size_changed = (prev.last_agreed_sect != md->la_size_sect);
 
     md_moved = prev.md_offset    != md->md_offset
         || prev.md_size_sect != md->md_size_sect;
 
     if (la_size_changed || md_moved || rs) {
         u32 prev_flags;
 
         /* We do some synchronous IO below, which may take some time.
          * Clear the timer, to avoid scary "timer expired!" messages,
          * "Superblock" is written out at least twice below, anyways. */
         del_timer(&device->md_sync_timer);
 
         /* We won't change the "al-extents" setting, we just may need
          * to move the on-disk location of the activity log ringbuffer.
          * Lock for transaction is good enough, it may well be "dirty"
          * or even "starving". */
         wait_event(device->al_wait, lc_try_lock_for_transaction(device->act_log));
 
         /* mark current on-disk bitmap and activity log as unreliable */
         prev_flags = md->flags;
         md->flags |= MDF_FULL_SYNC | MDF_AL_DISABLED;
         drbd_md_write(device, buffer);
 
         drbd_al_initialize(device, buffer);
 
         drbd_info(device, "Writing the whole bitmap, %s\n",
              la_size_changed && md_moved ? "size changed and md moved" :
              la_size_changed ? "size changed" : "md moved");
         /* next line implicitly does drbd_suspend_io()+drbd_resume_io() */
         drbd_bitmap_io(device, md_moved ? &drbd_bm_write_all : &drbd_bm_write,
                    "size changed", BM_LOCKED_MASK);
 
         /* on-disk bitmap and activity log is authoritative again
          * (unless there was an IO error meanwhile...) */
         md->flags = prev_flags;
         drbd_md_write(device, buffer);
 
         if (rs)
             drbd_info(device, "Changed AL layout to al-stripes = %d, al-stripe-size-kB = %d\n",
                   md->al_stripes, md->al_stripe_size_4k * 4);
     }
 
     if (size > prev.last_agreed_sect)
         rv = prev.last_agreed_sect ? DS_GREW : DS_GREW_FROM_ZERO;
     if (size < prev.last_agreed_sect)
         rv = DS_SHRUNK;
 
     if (0) {
     err_out:
         /* restore previous offset and sizes */
         md->la_size_sect = prev.last_agreed_sect;
         md->md_offset = prev.md_offset;
         md->al_offset = prev.al_offset;
         md->bm_offset = prev.bm_offset;
         md->md_size_sect = prev.md_size_sect;
         md->al_stripes = prev.al_stripes;
         md->al_stripe_size_4k = prev.al_stripe_size_4k;
         md->al_size_4k = (u64)prev.al_stripes * prev.al_stripe_size_4k;
     }
     lc_unlock(device->act_log);
     wake_up(&device->al_wait);
     drbd_md_put_buffer(device);
     drbd_resume_io(device);
 
     return rv;
 }
 
 sector_t
 drbd_new_dev_size(struct drbd_device *device, struct drbd_backing_dev *bdev,
           sector_t u_size, int assume_peer_has_space)
 {
     sector_t p_size = device->p_size;   /* partner's disk size. */
     sector_t la_size_sect = bdev->md.la_size_sect; /* last agreed size. */
     sector_t m_size; /* my size */
     sector_t size = 0;
 
     m_size = drbd_get_max_capacity(bdev);
 
     if (device->state.conn < C_CONNECTED && assume_peer_has_space) {
         drbd_warn(device, "Resize while not connected was forced by the user!\n");
         p_size = m_size;
     }
 
     if (p_size && m_size) {
         size = min_t(sector_t, p_size, m_size);
     } else {
         if (la_size_sect) {
             size = la_size_sect;
             if (m_size && m_size < size)
                 size = m_size;
             if (p_size && p_size < size)
                 size = p_size;
         } else {
             if (m_size)
                 size = m_size;
             if (p_size)
                 size = p_size;
         }
     }
 
     if (size == 0)
         drbd_err(device, "Both nodes diskless!\n");
 
     if (u_size) {
         if (u_size > size)
             drbd_err(device, "Requested disk size is too big (%lu > %lu)\n",
                 (unsigned long)u_size>>1, (unsigned long)size>>1);
         else
             size = u_size;
     }
 
     return size;
 }
 
 /*
  * drbd_check_al_size() - Ensures that the AL is of the right size
  * @device: DRBD device.
  *
  * Returns -EBUSY if current al lru is still used, -ENOMEM when allocation
  * failed, and 0 on success. You should call drbd_md_sync() after you called
  * this function.
  */
 static int drbd_check_al_size(struct drbd_device *device, struct disk_conf *dc)
 {
     struct lru_cache *n, *t;
     struct lc_element *e;
     unsigned int in_use;
     int i;
 
     if (device->act_log &&
         device->act_log->nr_elements == dc->al_extents)
         return 0;
 
     in_use = 0;
     t = device->act_log;
     n = lc_create("act_log", drbd_al_ext_cache, AL_UPDATES_PER_TRANSACTION,
         dc->al_extents, sizeof(struct lc_element), 0);
 
     if (n == NULL) {
         drbd_err(device, "Cannot allocate act_log lru!\n");
         return -ENOMEM;
     }
     spin_lock_irq(&device->al_lock);
     if (t) {
         for (i = 0; i < t->nr_elements; i++) {
             e = lc_element_by_index(t, i);
             if (e->refcnt)
                 drbd_err(device, "refcnt(%d)==%d\n",
                     e->lc_number, e->refcnt);
             in_use += e->refcnt;
         }
     }
     if (!in_use)
         device->act_log = n;
     spin_unlock_irq(&device->al_lock);
     if (in_use) {
         drbd_err(device, "Activity log still in use!\n");
         lc_destroy(n);
         return -EBUSY;
     } else {
         lc_destroy(t);
     }
     drbd_md_mark_dirty(device); /* we changed device->act_log->nr_elemens */
     return 0;
 }
 
 static void blk_queue_discard_granularity(struct request_queue *q, unsigned int granularity)
 {
     q->limits.discard_granularity = granularity;
 }
 
 static unsigned int drbd_max_discard_sectors(struct drbd_connection *connection)
 {
     /* when we introduced REQ_WRITE_SAME support, we also bumped
      * our maximum supported batch bio size used for discards. */
     if (connection->agreed_features & DRBD_FF_WSAME)
         return DRBD_MAX_BBIO_SECTORS;
     /* before, with DRBD <= 8.4.6, we only allowed up to one AL_EXTENT_SIZE. */
     return AL_EXTENT_SIZE >> 9;
 }
 
 static void decide_on_discard_support(struct drbd_device *device,
         struct drbd_backing_dev *bdev)
 {
     struct drbd_connection *connection =
         first_peer_device(device)->connection;
     struct request_queue *q = device->rq_queue;
 
     if (bdev && !bdev_max_discard_sectors(bdev->backing_bdev))
         goto not_supported;
 
     if (connection->cstate >= C_CONNECTED &&
         !(connection->agreed_features & DRBD_FF_TRIM)) {
         drbd_info(connection,
             "peer DRBD too old, does not support TRIM: disabling discards\n");
         goto not_supported;
     }
 
     /*
      * We don't care for the granularity, really.
      *
      * Stacking limits below should fix it for the local device.  Whether or
      * not it is a suitable granularity on the remote device is not our
      * problem, really. If you care, you need to use devices with similar
      * topology on all peers.
      */
     blk_queue_discard_granularity(q, 512);
     q->limits.max_discard_sectors = drbd_max_discard_sectors(connection);
     q->limits.max_write_zeroes_sectors =
         drbd_max_discard_sectors(connection);
     return;
 
 not_supported:
     blk_queue_discard_granularity(q, 0);
     q->limits.max_discard_sectors = 0;
     q->limits.max_write_zeroes_sectors = 0;
 }
 
 static void fixup_write_zeroes(struct drbd_device *device, struct request_queue *q)
 {
     /* Fixup max_write_zeroes_sectors after blk_stack_limits():
      * if we can handle "zeroes" efficiently on the protocol,
      * we want to do that, even if our backend does not announce
      * max_write_zeroes_sectors itself. */
     struct drbd_connection *connection = first_peer_device(device)->connection;
     /* If the peer announces WZEROES support, use it.  Otherwise, rather
      * send explicit zeroes than rely on some discard-zeroes-data magic. */
     if (connection->agreed_features & DRBD_FF_WZEROES)
         q->limits.max_write_zeroes_sectors = DRBD_MAX_BBIO_SECTORS;
     else
         q->limits.max_write_zeroes_sectors = 0;
 }
 
 static void drbd_setup_queue_param(struct drbd_device *device, struct drbd_backing_dev *bdev,
                    unsigned int max_bio_size, struct o_qlim *o)
 {
     struct request_queue * const q = device->rq_queue;
     unsigned int max_hw_sectors = max_bio_size >> 9;
     unsigned int max_segments = 0;
     struct request_queue *b = NULL;
     struct disk_conf *dc;
 
     if (bdev) {
         b = bdev->backing_bdev->bd_disk->queue;
 
         max_hw_sectors = min(queue_max_hw_sectors(b), max_bio_size >> 9);
         rcu_read_lock();
         dc = rcu_dereference(device->ldev->disk_conf);
         max_segments = dc->max_bio_bvecs;
         rcu_read_unlock();
 
         blk_set_stacking_limits(&q->limits);
     }
 
     blk_queue_max_hw_sectors(q, max_hw_sectors);
     /* This is the workaround for "bio would need to, but cannot, be split" */
     blk_queue_max_segments(q, max_segments ? max_segments : BLK_MAX_SEGMENTS);
     blk_queue_segment_boundary(q, PAGE_SIZE-1);
     decide_on_discard_support(device, bdev);
 
     if (b) {
         blk_stack_limits(&q->limits, &b->limits, 0);
         disk_update_readahead(device->vdisk);
     }
     fixup_write_zeroes(device, q);
 }
 
 void drbd_reconsider_queue_parameters(struct drbd_device *device, struct drbd_backing_dev *bdev, struct o_qlim *o)
 {
     unsigned int now, new, local, peer;
 
     now = queue_max_hw_sectors(device->rq_queue) << 9;
     local = device->local_max_bio_size; /* Eventually last known value, from volatile memory */
     peer = device->peer_max_bio_size; /* Eventually last known value, from meta data */
 
     if (bdev) {
         local = queue_max_hw_sectors(bdev->backing_bdev->bd_disk->queue) << 9;
         device->local_max_bio_size = local;
     }
     local = min(local, DRBD_MAX_BIO_SIZE);
 
     /* We may ignore peer limits if the peer is modern enough.
        Because new from 8.3.8 onwards the peer can use multiple
        BIOs for a single peer_request */
     if (device->state.conn >= C_WF_REPORT_PARAMS) {
         if (first_peer_device(device)->connection->agreed_pro_version < 94)
             peer = min(device->peer_max_bio_size, DRBD_MAX_SIZE_H80_PACKET);
             /* Correct old drbd (up to 8.3.7) if it believes it can do more than 32KiB */
         else if (first_peer_device(device)->connection->agreed_pro_version == 94)
             peer = DRBD_MAX_SIZE_H80_PACKET;
         else if (first_peer_device(device)->connection->agreed_pro_version < 100)
             peer = DRBD_MAX_BIO_SIZE_P95;  /* drbd 8.3.8 onwards, before 8.4.0 */
         else
             peer = DRBD_MAX_BIO_SIZE;
 
         /* We may later detach and re-attach on a disconnected Primary.
          * Avoid this setting to jump back in that case.
          * We want to store what we know the peer DRBD can handle,
          * not what the peer IO backend can handle. */
         if (peer > device->peer_max_bio_size)
             device->peer_max_bio_size = peer;
     }
     new = min(local, peer);
 
     if (device->state.role == R_PRIMARY && new < now)
         drbd_err(device, "ASSERT FAILED new < now; (%u < %u)\n", new, now);
 
     if (new != now)
         drbd_info(device, "max BIO size = %u\n", new);
 
     drbd_setup_queue_param(device, bdev, new, o);
 }
 
 /* Starts the worker thread */
 static void conn_reconfig_start(struct drbd_connection *connection)
 {
     drbd_thread_start(&connection->worker);
     drbd_flush_workqueue(&connection->sender_work);
 }
 
 /* if still unconfigured, stops worker again. */
 static void conn_reconfig_done(struct drbd_connection *connection)
 {
     bool stop_threads;
     spin_lock_irq(&connection->resource->req_lock);
     stop_threads = conn_all_vols_unconf(connection) &&
         connection->cstate == C_STANDALONE;
     spin_unlock_irq(&connection->resource->req_lock);
     if (stop_threads) {
         /* ack_receiver thread and ack_sender workqueue are implicitly
          * stopped by receiver in conn_disconnect() */
         drbd_thread_stop(&connection->receiver);
         drbd_thread_stop(&connection->worker);
     }
 }
 
 /* Make sure IO is suspended before calling this function(). */
 static void drbd_suspend_al(struct drbd_device *device)
 {
     int s = 0;
 
     if (!lc_try_lock(device->act_log)) {
         drbd_warn(device, "Failed to lock al in drbd_suspend_al()\n");
         return;
     }
 
     drbd_al_shrink(device);
     spin_lock_irq(&device->resource->req_lock);
     if (device->state.conn < C_CONNECTED)
         s = !test_and_set_bit(AL_SUSPENDED, &device->flags);
     spin_unlock_irq(&device->resource->req_lock);
     lc_unlock(device->act_log);
 
     if (s)
         drbd_info(device, "Suspended AL updates\n");
 }
 
 
 static bool should_set_defaults(struct genl_info *info)
 {
     unsigned flags = ((struct drbd_genlmsghdr*)info->userhdr)->flags;
     return 0 != (flags & DRBD_GENL_F_SET_DEFAULTS);
 }
 
 static unsigned int drbd_al_extents_max(struct drbd_backing_dev *bdev)
 {
     /* This is limited by 16 bit "slot" numbers,
      * and by available on-disk context storage.
      *
      * Also (u16)~0 is special (denotes a "free" extent).
      *
      * One transaction occupies one 4kB on-disk block,
      * we have n such blocks in the on disk ring buffer,
      * the "current" transaction may fail (n-1),
      * and there is 919 slot numbers context information per transaction.
      *
      * 72 transaction blocks amounts to more than 2**16 context slots,
      * so cap there first.
      */
     const unsigned int max_al_nr = DRBD_AL_EXTENTS_MAX;
     const unsigned int sufficient_on_disk =
         (max_al_nr + AL_CONTEXT_PER_TRANSACTION -1)
         /AL_CONTEXT_PER_TRANSACTION;
 
     unsigned int al_size_4k = bdev->md.al_size_4k;
 
     if (al_size_4k > sufficient_on_disk)
         return max_al_nr;
 
     return (al_size_4k - 1) * AL_CONTEXT_PER_TRANSACTION;
 }
 
 static bool write_ordering_changed(struct disk_conf *a, struct disk_conf *b)
 {
     return  a->disk_barrier != b->disk_barrier ||
         a->disk_flushes != b->disk_flushes ||
         a->disk_drain != b->disk_drain;
 }
 
 static void sanitize_disk_conf(struct drbd_device *device, struct disk_conf *disk_conf,
                    struct drbd_backing_dev *nbc)
 {
     struct block_device *bdev = nbc->backing_bdev;
 
     if (disk_conf->al_extents < DRBD_AL_EXTENTS_MIN)
         disk_conf->al_extents = DRBD_AL_EXTENTS_MIN;
     if (disk_conf->al_extents > drbd_al_extents_max(nbc))
         disk_conf->al_extents = drbd_al_extents_max(nbc);
 
     if (!bdev_max_discard_sectors(bdev)) {
         if (disk_conf->rs_discard_granularity) {
             disk_conf->rs_discard_granularity = 0; /* disable feature */
             drbd_info(device, "rs_discard_granularity feature disabled\n");
         }
     }
 
     if (disk_conf->rs_discard_granularity) {
         int orig_value = disk_conf->rs_discard_granularity;
         sector_t discard_size = bdev_max_discard_sectors(bdev) << 9;
         unsigned int discard_granularity = bdev_discard_granularity(bdev);
         int remainder;
 
         if (discard_granularity > disk_conf->rs_discard_granularity)
             disk_conf->rs_discard_granularity = discard_granularity;
 
         remainder = disk_conf->rs_discard_granularity %
                 discard_granularity;
         disk_conf->rs_discard_granularity += remainder;
 
         if (disk_conf->rs_discard_granularity > discard_size)
             disk_conf->rs_discard_granularity = discard_size;
 
         if (disk_conf->rs_discard_granularity != orig_value)
             drbd_info(device, "rs_discard_granularity changed to %d\n",
                   disk_conf->rs_discard_granularity);
     }
 }
 
 static int disk_opts_check_al_size(struct drbd_device *device, struct disk_conf *dc)
 {
     int err = -EBUSY;
 
     if (device->act_log &&
         device->act_log->nr_elements == dc->al_extents)
         return 0;
 
     drbd_suspend_io(device);
     /* If IO completion is currently blocked, we would likely wait
      * "forever" for the activity log to become unused. So we don't. */
     if (atomic_read(&device->ap_bio_cnt))
         goto out;
 
     wait_event(device->al_wait, lc_try_lock(device->act_log));
     drbd_al_shrink(device);
     err = drbd_check_al_size(device, dc);
     lc_unlock(device->act_log);
     wake_up(&device->al_wait);
 out:
     drbd_resume_io(device);
     return err;
 }
 
 int drbd_adm_disk_opts(struct sk_buff *skb, struct genl_info *info)
 {
     struct drbd_config_context adm_ctx;
     enum drbd_ret_code retcode;
     struct drbd_device *device;
     struct disk_conf *new_disk_conf, *old_disk_conf;
     struct fifo_buffer *old_plan = NULL, *new_plan = NULL;
     int err;
     unsigned int fifo_size;
 
     retcode = drbd_adm_prepare(&adm_ctx, skb, info, DRBD_ADM_NEED_MINOR);
     if (!adm_ctx.reply_skb)
         return retcode;
     if (retcode != NO_ERROR)
         goto finish;
 
     device = adm_ctx.device;
     mutex_lock(&adm_ctx.resource->adm_mutex);
 
     /* we also need a disk
      * to change the options on */
     if (!get_ldev(device)) {
         retcode = ERR_NO_DISK;
         goto out;
     }
 
     new_disk_conf = kmalloc(sizeof(struct disk_conf), GFP_KERNEL);
     if (!new_disk_conf) {
         retcode = ERR_NOMEM;
         goto fail;
     }
 
     mutex_lock(&device->resource->conf_update);
     old_disk_conf = device->ldev->disk_conf;
     *new_disk_conf = *old_disk_conf;
     if (should_set_defaults(info))
         set_disk_conf_defaults(new_disk_conf);
 
     err = disk_conf_from_attrs_for_change(new_disk_conf, info);
     if (err && err != -ENOMSG) {
         retcode = ERR_MANDATORY_TAG;
         drbd_msg_put_info(adm_ctx.reply_skb, from_attrs_err_to_txt(err));
         goto fail_unlock;
     }
 
     if (!expect(new_disk_conf->resync_rate >= 1))
         new_disk_conf->resync_rate = 1;
 
     sanitize_disk_conf(device, new_disk_conf, device->ldev);
 
     if (new_disk_conf->c_plan_ahead > DRBD_C_PLAN_AHEAD_MAX)
         new_disk_conf->c_plan_ahead = DRBD_C_PLAN_AHEAD_MAX;
 
     fifo_size = (new_disk_conf->c_plan_ahead * 10 * SLEEP_TIME) / HZ;
     if (fifo_size != device->rs_plan_s->size) {
         new_plan = fifo_alloc(fifo_size);
         if (!new_plan) {
             drbd_err(device, "kmalloc of fifo_buffer failed");
             retcode = ERR_NOMEM;
             goto fail_unlock;
         }
     }
 
     err = disk_opts_check_al_size(device, new_disk_conf);
     if (err) {
         /* Could be just "busy". Ignore?
          * Introduce dedicated error code? */
         drbd_msg_put_info(adm_ctx.reply_skb,
             "Try again without changing current al-extents setting");
         retcode = ERR_NOMEM;
         goto fail_unlock;
     }
 
     lock_all_resources();
     retcode = drbd_resync_after_valid(device, new_disk_conf->resync_after);
     if (retcode == NO_ERROR) {
         rcu_assign_pointer(device->ldev->disk_conf, new_disk_conf);
         drbd_resync_after_changed(device);
     }
     unlock_all_resources();
 
     if (retcode != NO_ERROR)
         goto fail_unlock;
 
     if (new_plan) {
         old_plan = device->rs_plan_s;
         rcu_assign_pointer(device->rs_plan_s, new_plan);
     }
 
     mutex_unlock(&device->resource->conf_update);
 
     if (new_disk_conf->al_updates)
         device->ldev->md.flags &= ~MDF_AL_DISABLED;
     else
         device->ldev->md.flags |= MDF_AL_DISABLED;
 
     if (new_disk_conf->md_flushes)
         clear_bit(MD_NO_FUA, &device->flags);
     else
         set_bit(MD_NO_FUA, &device->flags);
 
     if (write_ordering_changed(old_disk_conf, new_disk_conf))
         drbd_bump_write_ordering(device->resource, NULL, WO_BDEV_FLUSH);
 
     if (old_disk_conf->discard_zeroes_if_aligned !=
         new_disk_conf->discard_zeroes_if_aligned)
         drbd_reconsider_queue_parameters(device, device->ldev, NULL);
 
     drbd_md_sync(device);
 
     if (device->state.conn >= C_CONNECTED) {
         struct drbd_peer_device *peer_device;
 
         for_each_peer_device(peer_device, device)
             drbd_send_sync_param(peer_device);
     }
 
     kvfree_rcu(old_disk_conf);
     kfree(old_plan);
     mod_timer(&device->request_timer, jiffies + HZ);
     goto success;
 
 fail_unlock:
     mutex_unlock(&device->resource->conf_update);
  fail:
     kfree(new_disk_conf);
     kfree(new_plan);
 success:
     put_ldev(device);
  out:
     mutex_unlock(&adm_ctx.resource->adm_mutex);
  finish:
     drbd_adm_finish(&adm_ctx, info, retcode);
     return 0;
 }
 
 static struct block_device *open_backing_dev(struct drbd_device *device,
         const char *bdev_path, void *claim_ptr, bool do_bd_link)
 {
     struct block_device *bdev;
     int err = 0;
 
     bdev = blkdev_get_by_path(bdev_path,
                   FMODE_READ | FMODE_WRITE | FMODE_EXCL, claim_ptr);
     if (IS_ERR(bdev)) {
         drbd_err(device, "open(\"%s\") failed with %ld\n",
                 bdev_path, PTR_ERR(bdev));
         return bdev;
     }
 
     if (!do_bd_link)
         return bdev;
 
     err = bd_link_disk_holder(bdev, device->vdisk);
     if (err) {
         blkdev_put(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
         drbd_err(device, "bd_link_disk_holder(\"%s\", ...) failed with %d\n",
                 bdev_path, err);
         bdev = ERR_PTR(err);
     }
     return bdev;
 }
 
 static int open_backing_devices(struct drbd_device *device,
         struct disk_conf *new_disk_conf,
         struct drbd_backing_dev *nbc)
 {
     struct block_device *bdev;
 
     bdev = open_backing_dev(device, new_disk_conf->backing_dev, device, true);
     if (IS_ERR(bdev))
         return ERR_OPEN_DISK;
     nbc->backing_bdev = bdev;
 
     /*
      * meta_dev_idx >= 0: external fixed size, possibly multiple
      * drbd sharing one meta device.  TODO in that case, paranoia
      * check that [md_bdev, meta_dev_idx] is not yet used by some
      * other drbd minor!  (if you use drbd.conf + drbdadm, that
      * should check it for you already; but if you don't, or
      * someone fooled it, we need to double check here)
      */
     bdev = open_backing_dev(device, new_disk_conf->meta_dev,
         /* claim ptr: device, if claimed exclusively; shared drbd_m_holder,
          * if potentially shared with other drbd minors */
             (new_disk_conf->meta_dev_idx < 0) ? (void*)device : (void*)drbd_m_holder,
         /* avoid double bd_claim_by_disk() for the same (source,target) tuple,
          * as would happen with internal metadata. */
             (new_disk_conf->meta_dev_idx != DRBD_MD_INDEX_FLEX_INT &&
              new_disk_conf->meta_dev_idx != DRBD_MD_INDEX_INTERNAL));
     if (IS_ERR(bdev))
         return ERR_OPEN_MD_DISK;
     nbc->md_bdev = bdev;
     return NO_ERROR;
 }
 
 static void close_backing_dev(struct drbd_device *device, struct block_device *bdev,
     bool do_bd_unlink)
 {
     if (!bdev)
         return;
     if (do_bd_unlink)
         bd_unlink_disk_holder(bdev, device->vdisk);
     blkdev_put(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
 }
 
 void drbd_backing_dev_free(struct drbd_device *device, struct drbd_backing_dev *ldev)
 {
     if (ldev == NULL)
         return;
 
     close_backing_dev(device, ldev->md_bdev, ldev->md_bdev != ldev->backing_bdev);
     close_backing_dev(device, ldev->backing_bdev, true);
 
     kfree(ldev->disk_conf);
     kfree(ldev);
 }
 
 int drbd_adm_attach(struct sk_buff *skb, struct genl_info *info)
 {
     struct drbd_config_context adm_ctx;
     struct drbd_device *device;
     struct drbd_peer_device *peer_device;
     struct drbd_connection *connection;
     int err;
     enum drbd_ret_code retcode;
     enum determine_dev_size dd;
     sector_t max_possible_sectors;
     sector_t min_md_device_sectors;
     struct drbd_backing_dev *nbc = NULL; /* new_backing_conf */
     struct disk_conf *new_disk_conf = NULL;
     struct lru_cache *resync_lru = NULL;
     struct fifo_buffer *new_plan = NULL;
     union drbd_state ns, os;
     enum drbd_state_rv rv;
     struct net_conf *nc;
 
     retcode = drbd_adm_prepare(&adm_ctx, skb, info, DRBD_ADM_NEED_MINOR);
     if (!adm_ctx.reply_skb)
         return retcode;
     if (retcode != NO_ERROR)
         goto finish;
 
     device = adm_ctx.device;
     mutex_lock(&adm_ctx.resource->adm_mutex);
     peer_device = first_peer_device(device);
     connection = peer_device->connection;
     conn_reconfig_start(connection);
 
     /* if you want to reconfigure, please tear down first */
     if (device->state.disk > D_DISKLESS) {
         retcode = ERR_DISK_CONFIGURED;
         goto fail;
     }
     /* It may just now have detached because of IO error.  Make sure
      * drbd_ldev_destroy is done already, we may end up here very fast,
      * e.g. if someone calls attach from the on-io-error handler,
      * to realize a "hot spare" feature (not that I'd recommend that) */
     wait_event(device->misc_wait, !test_bit(GOING_DISKLESS, &device->flags));
 
     /* make sure there is no leftover from previous force-detach attempts */
     clear_bit(FORCE_DETACH, &device->flags);
     clear_bit(WAS_IO_ERROR, &device->flags);
     clear_bit(WAS_READ_ERROR, &device->flags);
 
     /* and no leftover from previously aborted resync or verify, either */
     device->rs_total = 0;
     device->rs_failed = 0;
     atomic_set(&device->rs_pending_cnt, 0);
 
     /* allocation not in the IO path, drbdsetup context */
     nbc = kzalloc(sizeof(struct drbd_backing_dev), GFP_KERNEL);
     if (!nbc) {
         retcode = ERR_NOMEM;
         goto fail;
     }
     spin_lock_init(&nbc->md.uuid_lock);
 
     new_disk_conf = kzalloc(sizeof(struct disk_conf), GFP_KERNEL);
     if (!new_disk_conf) {
         retcode = ERR_NOMEM;
         goto fail;
     }
     nbc->disk_conf = new_disk_conf;
 
     set_disk_conf_defaults(new_disk_conf);
     err = disk_conf_from_attrs(new_disk_conf, info);
     if (err) {
         retcode = ERR_MANDATORY_TAG;
         drbd_msg_put_info(adm_ctx.reply_skb, from_attrs_err_to_txt(err));
         goto fail;
     }
 
     if (new_disk_conf->c_plan_ahead > DRBD_C_PLAN_AHEAD_MAX)
         new_disk_conf->c_plan_ahead = DRBD_C_PLAN_AHEAD_MAX;
 
     new_plan = fifo_alloc((new_disk_conf->c_plan_ahead * 10 * SLEEP_TIME) / HZ);
     if (!new_plan) {
         retcode = ERR_NOMEM;
         goto fail;
     }
 
     if (new_disk_conf->meta_dev_idx < DRBD_MD_INDEX_FLEX_INT) {
         retcode = ERR_MD_IDX_INVALID;
         goto fail;
     }
 
     rcu_read_lock();
     nc = rcu_dereference(connection->net_conf);
     if (nc) {
         if (new_disk_conf->fencing == FP_STONITH && nc->wire_protocol == DRBD_PROT_A) {
             rcu_read_unlock();
             retcode = ERR_STONITH_AND_PROT_A;
             goto fail;
         }
     }
     rcu_read_unlock();
 
     retcode = open_backing_devices(device, new_disk_conf, nbc);
     if (retcode != NO_ERROR)
         goto fail;
 
     if ((nbc->backing_bdev == nbc->md_bdev) !=
         (new_disk_conf->meta_dev_idx == DRBD_MD_INDEX_INTERNAL ||
          new_disk_conf->meta_dev_idx == DRBD_MD_INDEX_FLEX_INT)) {
         retcode = ERR_MD_IDX_INVALID;
         goto fail;
     }
 
     resync_lru = lc_create("resync", drbd_bm_ext_cache,
             1, 61, sizeof(struct bm_extent),
             offsetof(struct bm_extent, lce));
     if (!resync_lru) {
         retcode = ERR_NOMEM;
         goto fail;
     }
 
     /* Read our meta data super block early.
      * This also sets other on-disk offsets. */
     retcode = drbd_md_read(device, nbc);
     if (retcode != NO_ERROR)
         goto fail;
 
     sanitize_disk_conf(device, new_disk_conf, nbc);
 
     if (drbd_get_max_capacity(nbc) < new_disk_conf->disk_size) {
         drbd_err(device, "max capacity %llu smaller than disk size %llu\n",
             (unsigned long long) drbd_get_max_capacity(nbc),
             (unsigned long long) new_disk_conf->disk_size);
         retcode = ERR_DISK_TOO_SMALL;
         goto fail;
     }
 
     if (new_disk_conf->meta_dev_idx < 0) {
         max_possible_sectors = DRBD_MAX_SECTORS_FLEX;
         /* at least one MB, otherwise it does not make sense */
         min_md_device_sectors = (2<<10);
     } else {
         max_possible_sectors = DRBD_MAX_SECTORS;
         min_md_device_sectors = MD_128MB_SECT * (new_disk_conf->meta_dev_idx + 1);
     }
 
     if (drbd_get_capacity(nbc->md_bdev) < min_md_device_sectors) {
         retcode = ERR_MD_DISK_TOO_SMALL;
         drbd_warn(device, "refusing attach: md-device too small, "
              "at least %llu sectors needed for this meta-disk type\n",
              (unsigned long long) min_md_device_sectors);
         goto fail;
     }
 
     /* Make sure the new disk is big enough
      * (we may currently be R_PRIMARY with no local disk...) */
     if (drbd_get_max_capacity(nbc) < get_capacity(device->vdisk)) {
         retcode = ERR_DISK_TOO_SMALL;
         goto fail;
     }
 
     nbc->known_size = drbd_get_capacity(nbc->backing_bdev);
 
     if (nbc->known_size > max_possible_sectors) {
         drbd_warn(device, "==> truncating very big lower level device "
             "to currently maximum possible %llu sectors <==\n",
             (unsigned long long) max_possible_sectors);
         if (new_disk_conf->meta_dev_idx >= 0)
             drbd_warn(device, "==>> using internal or flexible "
                       "meta data may help <<==\n");
     }
 
     drbd_suspend_io(device);
     /* also wait for the last barrier ack. */
     /* FIXME see also https://daiquiri.linbit/cgi-bin/bugzilla/show_bug.cgi?id=171
      * We need a way to either ignore barrier acks for barriers sent before a device
      * was attached, or a way to wait for all pending barrier acks to come in.
      * As barriers are counted per resource,
      * we'd need to suspend io on all devices of a resource.
      */
     wait_event(device->misc_wait, !atomic_read(&device->ap_pending_cnt) || drbd_suspended(device));
     /* and for any other previously queued work */
     drbd_flush_workqueue(&connection->sender_work);
 
     rv = _drbd_request_state(device, NS(disk, D_ATTACHING), CS_VERBOSE);
     retcode = (enum drbd_ret_code)rv;
     drbd_resume_io(device);
     if (rv < SS_SUCCESS)
         goto fail;
 
     if (!get_ldev_if_state(device, D_ATTACHING))
         goto force_diskless;
 
     if (!device->bitmap) {
         if (drbd_bm_init(device)) {
             retcode = ERR_NOMEM;
             goto force_diskless_dec;
         }
     }
 
     if (device->state.pdsk != D_UP_TO_DATE && device->ed_uuid &&
         (device->state.role == R_PRIMARY || device->state.peer == R_PRIMARY) &&
             (device->ed_uuid & ~((u64)1)) != (nbc->md.uuid[UI_CURRENT] & ~((u64)1))) {
         drbd_err(device, "Can only attach to data with current UUID=%016llX\n",
             (unsigned long long)device->ed_uuid);
         retcode = ERR_DATA_NOT_CURRENT;
         goto force_diskless_dec;
     }
 
     /* Since we are diskless, fix the activity log first... */
     if (drbd_check_al_size(device, new_disk_conf)) {
         retcode = ERR_NOMEM;
         goto force_diskless_dec;
     }
 
     /* Prevent shrinking of consistent devices ! */
     {
     unsigned long long nsz = drbd_new_dev_size(device, nbc, nbc->disk_conf->disk_size, 0);
     unsigned long long eff = nbc->md.la_size_sect;
     if (drbd_md_test_flag(nbc, MDF_CONSISTENT) && nsz < eff) {
         if (nsz == nbc->disk_conf->disk_size) {
             drbd_warn(device, "truncating a consistent device during attach (%llu < %llu)\n", nsz, eff);
         } else {
             drbd_warn(device, "refusing to truncate a consistent device (%llu < %llu)\n", nsz, eff);
             drbd_msg_sprintf_info(adm_ctx.reply_skb,
                 "To-be-attached device has last effective > current size, and is consistent\n"
                 "(%llu > %llu sectors). Refusing to attach.", eff, nsz);
             retcode = ERR_IMPLICIT_SHRINK;
             goto force_diskless_dec;
         }
     }
     }
 
     lock_all_resources();
     retcode = drbd_resync_after_valid(device, new_disk_conf->resync_after);
     if (retcode != NO_ERROR) {
         unlock_all_resources();
         goto force_diskless_dec;
     }
 
     /* Reset the "barriers don't work" bits here, then force meta data to
      * be written, to ensure we determine if barriers are supported. */
     if (new_disk_conf->md_flushes)
         clear_bit(MD_NO_FUA, &device->flags);
     else
         set_bit(MD_NO_FUA, &device->flags);
 
     /* Point of no return reached.
      * Devices and memory are no longer released by error cleanup below.
      * now device takes over responsibility, and the state engine should
      * clean it up somewhere.  */
     D_ASSERT(device, device->ldev == NULL);
     device->ldev = nbc;
     device->resync = resync_lru;
     device->rs_plan_s = new_plan;
     nbc = NULL;
     resync_lru = NULL;
     new_disk_conf = NULL;
     new_plan = NULL;
 
     drbd_resync_after_changed(device);
     drbd_bump_write_ordering(device->resource, device->ldev, WO_BDEV_FLUSH);
     unlock_all_resources();
 
     if (drbd_md_test_flag(device->ldev, MDF_CRASHED_PRIMARY))
         set_bit(CRASHED_PRIMARY, &device->flags);
     else
         clear_bit(CRASHED_PRIMARY, &device->flags);
 
     if (drbd_md_test_flag(device->ldev, MDF_PRIMARY_IND) &&
         !(device->state.role == R_PRIMARY && device->resource->susp_nod))
         set_bit(CRASHED_PRIMARY, &device->flags);
 
     device->send_cnt = 0;
     device->recv_cnt = 0;
     device->read_cnt = 0;
     device->writ_cnt = 0;
 
     drbd_reconsider_queue_parameters(device, device->ldev, NULL);
 
     /* If I am currently not R_PRIMARY,
      * but meta data primary indicator is set,
      * I just now recover from a hard crash,
      * and have been R_PRIMARY before that crash.
      *
      * Now, if I had no connection before that crash
      * (have been degraded R_PRIMARY), chances are that
      * I won't find my peer now either.
      *
      * In that case, and _only_ in that case,
      * we use the degr-wfc-timeout instead of the default,
      * so we can automatically recover from a crash of a
      * degraded but active "cluster" after a certain timeout.
      */
     clear_bit(USE_DEGR_WFC_T, &device->flags);
     if (device->state.role != R_PRIMARY &&
          drbd_md_test_flag(device->ldev, MDF_PRIMARY_IND) &&
         !drbd_md_test_flag(device->ldev, MDF_CONNECTED_IND))
         set_bit(USE_DEGR_WFC_T, &device->flags);
 
     dd = drbd_determine_dev_size(device, 0, NULL);
     if (dd <= DS_ERROR) {
         retcode = ERR_NOMEM_BITMAP;
         goto force_diskless_dec;
     } else if (dd == DS_GREW)
         set_bit(RESYNC_AFTER_NEG, &device->flags);
 
     if (drbd_md_test_flag(device->ldev, MDF_FULL_SYNC) ||
         (test_bit(CRASHED_PRIMARY, &device->flags) &&
          drbd_md_test_flag(device->ldev, MDF_AL_DISABLED))) {
         drbd_info(device, "Assuming that all blocks are out of sync "
              "(aka FullSync)\n");
         if (drbd_bitmap_io(device, &drbd_bmio_set_n_write,
             "set_n_write from attaching", BM_LOCKED_MASK)) {
             retcode = ERR_IO_MD_DISK;
             goto force_diskless_dec;
         }
     } else {
         if (drbd_bitmap_io(device, &drbd_bm_read,
             "read from attaching", BM_LOCKED_MASK)) {
             retcode = ERR_IO_MD_DISK;
             goto force_diskless_dec;
         }
     }
 
     if (_drbd_bm_total_weight(device) == drbd_bm_bits(device))
         drbd_suspend_al(device); /* IO is still suspended here... */
 
     spin_lock_irq(&device->resource->req_lock);
     os = drbd_read_state(device);
     ns = os;
     /* If MDF_CONSISTENT is not set go into inconsistent state,
        otherwise investigate MDF_WasUpToDate...
        If MDF_WAS_UP_TO_DATE is not set go into D_OUTDATED disk state,
        otherwise into D_CONSISTENT state.
     */
     if (drbd_md_test_flag(device->ldev, MDF_CONSISTENT)) {
         if (drbd_md_test_flag(device->ldev, MDF_WAS_UP_TO_DATE))
             ns.disk = D_CONSISTENT;
         else
             ns.disk = D_OUTDATED;
     } else {
         ns.disk = D_INCONSISTENT;
     }
 
     if (drbd_md_test_flag(device->ldev, MDF_PEER_OUT_DATED))
         ns.pdsk = D_OUTDATED;
 
     rcu_read_lock();
     if (ns.disk == D_CONSISTENT &&
         (ns.pdsk == D_OUTDATED || rcu_dereference(device->ldev->disk_conf)->fencing == FP_DONT_CARE))
         ns.disk = D_UP_TO_DATE;
 
     /* All tests on MDF_PRIMARY_IND, MDF_CONNECTED_IND,
        MDF_CONSISTENT and MDF_WAS_UP_TO_DATE must happen before
        this point, because drbd_request_state() modifies these
        flags. */
 
     if (rcu_dereference(device->ldev->disk_conf)->al_updates)
         device->ldev->md.flags &= ~MDF_AL_DISABLED;
     else
         device->ldev->md.flags |= MDF_AL_DISABLED;
 
     rcu_read_unlock();
 
     /* In case we are C_CONNECTED postpone any decision on the new disk
        state after the negotiation phase. */
     if (device->state.conn == C_CONNECTED) {
         device->new_state_tmp.i = ns.i;
         ns.i = os.i;
         ns.disk = D_NEGOTIATING;
 
         /* We expect to receive up-to-date UUIDs soon.
            To avoid a race in receive_state, free p_uuid while
            holding req_lock. I.e. atomic with the state change */
         kfree(device->p_uuid);
         device->p_uuid = NULL;
     }
 
     rv = _drbd_set_state(device, ns, CS_VERBOSE, NULL);
     spin_unlock_irq(&device->resource->req_lock);
 
     if (rv < SS_SUCCESS)
         goto force_diskless_dec;
 
     mod_timer(&device->request_timer, jiffies + HZ);
 
     if (device->state.role == R_PRIMARY)
         device->ldev->md.uuid[UI_CURRENT] |=  (u64)1;
     else
         device->ldev->md.uuid[UI_CURRENT] &= ~(u64)1;
 
     drbd_md_mark_dirty(device);
     drbd_md_sync(device);
 
     kobject_uevent(&disk_to_dev(device->vdisk)->kobj, KOBJ_CHANGE);
     put_ldev(device);
     conn_reconfig_done(connection);
     mutex_unlock(&adm_ctx.resource->adm_mutex);
     drbd_adm_finish(&adm_ctx, info, retcode);
     return 0;
 
  force_diskless_dec:
     put_ldev(device);
  force_diskless:
     drbd_force_state(device, NS(disk, D_DISKLESS));
     drbd_md_sync(device);
  fail:
     conn_reconfig_done(connection);
     if (nbc) {
         close_backing_dev(device, nbc->md_bdev, nbc->md_bdev != nbc->backing_bdev);
         close_backing_dev(device, nbc->backing_bdev, true);
         kfree(nbc);
     }
     kfree(new_disk_conf);
     lc_destroy(resync_lru);
     kfree(new_plan);
     mutex_unlock(&adm_ctx.resource->adm_mutex);
  finish:
     drbd_adm_finish(&adm_ctx, info, retcode);
     return 0;
 }
 
 static int adm_detach(struct drbd_device *device, int force)
 {
     if (force) {
         set_bit(FORCE_DETACH, &device->flags);
         drbd_force_state(device, NS(disk, D_FAILED));
         return SS_SUCCESS;
     }
 
     return drbd_request_detach_interruptible(device);
 }
 
 /* Detaching the disk is a process in multiple stages.  First we need to lock
  * out application IO, in-flight IO, IO stuck in drbd_al_begin_io.
  * Then we transition to D_DISKLESS, and wait for put_ldev() to return all
  * internal references as well.
  * Only then we have finally detached. */
 int drbd_adm_detach(struct sk_buff *skb, struct genl_info *info)
 {
     struct drbd_config_context adm_ctx;
     enum drbd_ret_code retcode;
     struct detach_parms parms = { };
     int err;
 
     retcode = drbd_adm_prepare(&adm_ctx, skb, info, DRBD_ADM_NEED_MINOR);
     if (!adm_ctx.reply_skb)
         return retcode;
     if (retcode != NO_ERROR)
         goto out;
 
     if (info->attrs[DRBD_NLA_DETACH_PARMS]) {
         err = detach_parms_from_attrs(&parms, info);
         if (err) {
             retcode = ERR_MANDATORY_TAG;
             drbd_msg_put_info(adm_ctx.reply_skb, from_attrs_err_to_txt(err));
             goto out;
         }
     }
 
     mutex_lock(&adm_ctx.resource->adm_mutex);
     retcode = adm_detach(adm_ctx.device, parms.force_detach);
     mutex_unlock(&adm_ctx.resource->adm_mutex);
 out:
     drbd_adm_finish(&adm_ctx, info, retcode);
     return 0;
 }
 
 static bool conn_resync_running(struct drbd_connection *connection)
 {
     struct drbd_peer_device *peer_device;
     bool rv = false;
     int vnr;
 
     rcu_read_lock();
     idr_for_each_entry(&connection->peer_devices, peer_device, vnr) {
         struct drbd_device *device = peer_device->device;
         if (device->state.conn == C_SYNC_SOURCE ||
             device->state.conn == C_SYNC_TARGET ||
             device->state.conn == C_PAUSED_SYNC_S ||
             device->state.conn == C_PAUSED_SYNC_T) {
             rv = true;
             break;
         }
     }
     rcu_read_unlock();
 
     return rv;
 }
 
 static bool conn_ov_running(struct drbd_connection *connection)
 {
     struct drbd_peer_device *peer_device;
     bool rv = false;
     int vnr;
 
     rcu_read_lock();
     idr_for_each_entry(&connection->peer_devices, peer_device, vnr) {
         struct drbd_device *device = peer_device->device;
         if (device->state.conn == C_VERIFY_S ||
             device->state.conn == C_VERIFY_T) {
             rv = true;
             break;
         }
     }
     rcu_read_unlock();
 
     return rv;
 }
 
 static enum drbd_ret_code
 _check_net_options(struct drbd_connection *connection, struct net_conf *old_net_conf, struct net_conf *new_net_conf)
 {
     struct drbd_peer_device *peer_device;
     int i;
 
     if (old_net_conf && connection->cstate == C_WF_REPORT_PARAMS && connection->agreed_pro_version < 100) {
         if (new_net_conf->wire_protocol != old_net_conf->wire_protocol)
             return ERR_NEED_APV_100;
 
         if (new_net_conf->two_primaries != old_net_conf->two_primaries)
             return ERR_NEED_APV_100;
 
         if (strcmp(new_net_conf->integrity_alg, old_net_conf->integrity_alg))
             return ERR_NEED_APV_100;
     }
 
     if (!new_net_conf->two_primaries &&
         conn_highest_role(connection) == R_PRIMARY &&
         conn_highest_peer(connection) == R_PRIMARY)
         return ERR_NEED_ALLOW_TWO_PRI;
 
     if (new_net_conf->two_primaries &&
         (new_net_conf->wire_protocol != DRBD_PROT_C))
         return ERR_NOT_PROTO_C;
 
     idr_for_each_entry(&connection->peer_devices, peer_device, i) {
         struct drbd_device *device = peer_device->device;
         if (get_ldev(device)) {
             enum drbd_fencing_p fp = rcu_dereference(device->ldev->disk_conf)->fencing;
             put_ldev(device);
             if (new_net_conf->wire_protocol == DRBD_PROT_A && fp == FP_STONITH)
                 return ERR_STONITH_AND_PROT_A;
         }
         if (device->state.role == R_PRIMARY && new_net_conf->discard_my_data)
             return ERR_DISCARD_IMPOSSIBLE;
     }
 
     if (new_net_conf->on_congestion != OC_BLOCK && new_net_conf->wire_protocol != DRBD_PROT_A)
         return ERR_CONG_NOT_PROTO_A;
 
     return NO_ERROR;
 }
 
 static enum drbd_ret_code
 check_net_options(struct drbd_connection *connection, struct net_conf *new_net_conf)
 {
     enum drbd_ret_code rv;
     struct drbd_peer_device *peer_device;
     int i;
 
     rcu_read_lock();
     rv = _check_net_options(connection, rcu_dereference(connection->net_conf), new_net_conf);
     rcu_read_unlock();
 
     /* connection->peer_devices protected by genl_lock() here */
     idr_for_each_entry(&connection->peer_devices, peer_device, i) {
         struct drbd_device *device = peer_device->device;
         if (!device->bitmap) {
             if (drbd_bm_init(device))
                 return ERR_NOMEM;
         }
     }
 
     return rv;
 }
 
 struct crypto {
     struct crypto_shash *verify_tfm;
     struct crypto_shash *csums_tfm;
     struct crypto_shash *cram_hmac_tfm;
     struct crypto_shash *integrity_tfm;
 };
 
 static int
 alloc_shash(struct crypto_shash **tfm, char *tfm_name, int err_alg)
 {
     if (!tfm_name[0])
         return NO_ERROR;
 
     *tfm = crypto_alloc_shash(tfm_name, 0, 0);
     if (IS_ERR(*tfm)) {
         *tfm = NULL;
         return err_alg;
     }
 
     return NO_ERROR;
 }
 
 static enum drbd_ret_code
 alloc_crypto(struct crypto *crypto, struct net_conf *new_net_conf)
 {
     char hmac_name[CRYPTO_MAX_ALG_NAME];
     enum drbd_ret_code rv;
 
     rv = alloc_shash(&crypto->csums_tfm, new_net_conf->csums_alg,
              ERR_CSUMS_ALG);
     if (rv != NO_ERROR)
         return rv;
     rv = alloc_shash(&crypto->verify_tfm, new_net_conf->verify_alg,
              ERR_VERIFY_ALG);
     if (rv != NO_ERROR)
         return rv;
     rv = alloc_shash(&crypto->integrity_tfm, new_net_conf->integrity_alg,
              ERR_INTEGRITY_ALG);
     if (rv != NO_ERROR)
         return rv;
     if (new_net_conf->cram_hmac_alg[0] != 0) {
         snprintf(hmac_name, CRYPTO_MAX_ALG_NAME, "hmac(%s)",
              new_net_conf->cram_hmac_alg);
 
         rv = alloc_shash(&crypto->cram_hmac_tfm, hmac_name,
                  ERR_AUTH_ALG);
     }
 
     return rv;
 }
 
 static void free_crypto(struct crypto *crypto)
 {
     crypto_free_shash(crypto->cram_hmac_tfm);
     crypto_free_shash(crypto->integrity_tfm);
     crypto_free_shash(crypto->csums_tfm);
     crypto_free_shash(crypto->verify_tfm);
 }
 
 int drbd_adm_net_opts(struct sk_buff *skb, struct genl_info *info)
 {
     struct drbd_config_context adm_ctx;
     enum drbd_ret_code retcode;
     struct drbd_connection *connection;
     struct net_conf *old_net_conf, *new_net_conf = NULL;
     int err;
     int ovr; /* online verify running */
     int rsr; /* re-sync running */
     struct crypto crypto = { };
 
     retcode = drbd_adm_prepare(&adm_ctx, skb, info, DRBD_ADM_NEED_CONNECTION);
     if (!adm_ctx.reply_skb)
         return retcode;
     if (retcode != NO_ERROR)
         goto finish;
 
     connection = adm_ctx.connection;
     mutex_lock(&adm_ctx.resource->adm_mutex);
 
     new_net_conf = kzalloc(sizeof(struct net_conf), GFP_KERNEL);
     if (!new_net_conf) {
         retcode = ERR_NOMEM;
         goto out;
     }
 
     conn_reconfig_start(connection);
 
     mutex_lock(&connection->data.mutex);
     mutex_lock(&connection->resource->conf_update);
     old_net_conf = connection->net_conf;
 
     if (!old_net_conf) {
         drbd_msg_put_info(adm_ctx.reply_skb, "net conf missing, try connect");
         retcode = ERR_INVALID_REQUEST;
         goto fail;
     }
 
     *new_net_conf = *old_net_conf;
     if (should_set_defaults(info))
         set_net_conf_defaults(new_net_conf);
 
     err = net_conf_from_attrs_for_change(new_net_conf, info);
     if (err && err != -ENOMSG) {
         retcode = ERR_MANDATORY_TAG;
         drbd_msg_put_info(adm_ctx.reply_skb, from_attrs_err_to_txt(err));
         goto fail;
     }
 
     retcode = check_net_options(connection, new_net_conf);
     if (retcode != NO_ERROR)
         goto fail;
 
     /* re-sync running */
     rsr = conn_resync_running(connection);
     if (rsr && strcmp(new_net_conf->csums_alg, old_net_conf->csums_alg)) {
         retcode = ERR_CSUMS_RESYNC_RUNNING;
         goto fail;
     }
 
     /* online verify running */
     ovr = conn_ov_running(connection);
     if (ovr && strcmp(new_net_conf->verify_alg, old_net_conf->verify_alg)) {
         retcode = ERR_VERIFY_RUNNING;
         goto fail;
     }
 
     retcode = alloc_crypto(&crypto, new_net_conf);
     if (retcode != NO_ERROR)
         goto fail;
 
     rcu_assign_pointer(connection->net_conf, new_net_conf);
 
     if (!rsr) {
         crypto_free_shash(connection->csums_tfm);
         connection->csums_tfm = crypto.csums_tfm;
         crypto.csums_tfm = NULL;
     }
     if (!ovr) {
         crypto_free_shash(connection->verify_tfm);
         connection->verify_tfm = crypto.verify_tfm;
         crypto.verify_tfm = NULL;
     }
 
     crypto_free_shash(connection->integrity_tfm);
     connection->integrity_tfm = crypto.integrity_tfm;
     if (connection->cstate >= C_WF_REPORT_PARAMS && connection->agreed_pro_version >= 100)
         /* Do this without trying to take connection->data.mutex again.  */
         __drbd_send_protocol(connection, P_PROTOCOL_UPDATE);
 
     crypto_free_shash(connection->cram_hmac_tfm);
     connection->cram_hmac_tfm = crypto.cram_hmac_tfm;
 
     mutex_unlock(&connection->resource->conf_update);
     mutex_unlock(&connection->data.mutex);
     kvfree_rcu(old_net_conf);
 
     if (connection->cstate >= C_WF_REPORT_PARAMS) {
         struct drbd_peer_device *peer_device;
         int vnr;
 
         idr_for_each_entry(&connection->peer_devices, peer_device, vnr)
             drbd_send_sync_param(peer_device);
     }
 
     goto done;
 
  fail:
     mutex_unlock(&connection->resource->conf_update);
     mutex_unlock(&connection->data.mutex);
     free_crypto(&crypto);
     kfree(new_net_conf);
  done:
     conn_reconfig_done(connection);
  out:
     mutex_unlock(&adm_ctx.resource->adm_mutex);
  finish:
     drbd_adm_finish(&adm_ctx, info, retcode);
     return 0;
 }
 
 static void connection_to_info(struct connection_info *info,
                    struct drbd_connection *connection)
 {
     info->conn_connection_state = connection->cstate;
     info->conn_role = conn_highest_peer(connection);
 }
 
 static void peer_device_to_info(struct peer_device_info *info,
                 struct drbd_peer_device *peer_device)
 {
     struct drbd_device *device = peer_device->device;
 
     info->peer_repl_state =
         max_t(enum drbd_conns, C_WF_REPORT_PARAMS, device->state.conn);
     info->peer_disk_state = device->state.pdsk;
     info->peer_resync_susp_user = device->state.user_isp;
     info->peer_resync_susp_peer = device->state.peer_isp;
     info->peer_resync_susp_dependency = device->state.aftr_isp;
 }
 
 int drbd_adm_connect(struct sk_buff *skb, struct genl_info *info)
 {
     struct connection_info connection_info;
     enum drbd_notification_type flags;
     unsigned int peer_devices = 0;
     struct drbd_config_context adm_ctx;
     struct drbd_peer_device *peer_device;
     struct net_conf *old_net_conf, *new_net_conf = NULL;
     struct crypto crypto = { };
     struct drbd_resource *resource;
     struct drbd_connection *connection;
     enum drbd_ret_code retcode;
     enum drbd_state_rv rv;
     int i;
     int err;
 
     retcode = drbd_adm_prepare(&adm_ctx, skb, info, DRBD_ADM_NEED_RESOURCE);
 
     if (!adm_ctx.reply_skb)
         return retcode;
     if (retcode != NO_ERROR)
         goto out;
     if (!(adm_ctx.my_addr && adm_ctx.peer_addr)) {
         drbd_msg_put_info(adm_ctx.reply_skb, "connection endpoint(s) missing");
         retcode = ERR_INVALID_REQUEST;
         goto out;
     }
 
     /* No need for _rcu here. All reconfiguration is
      * strictly serialized on genl_lock(). We are protected against
      * concurrent reconfiguration/addition/deletion */
     for_each_resource(resource, &drbd_resources) {
         for_each_connection(connection, resource) {
             if (nla_len(adm_ctx.my_addr) == connection->my_addr_len &&
                 !memcmp(nla_data(adm_ctx.my_addr), &connection->my_addr,
                     connection->my_addr_len)) {
                 retcode = ERR_LOCAL_ADDR;
                 goto out;
             }
 
             if (nla_len(adm_ctx.peer_addr) == connection->peer_addr_len &&
                 !memcmp(nla_data(adm_ctx.peer_addr), &connection->peer_addr,
                     connection->peer_addr_len)) {
                 retcode = ERR_PEER_ADDR;
                 goto out;
             }
         }
     }
 
     mutex_lock(&adm_ctx.resource->adm_mutex);
     connection = first_connection(adm_ctx.resource);
     conn_reconfig_start(connection);
 
     if (connection->cstate > C_STANDALONE) {
         retcode = ERR_NET_CONFIGURED;
         goto fail;
     }
 
     /* allocation not in the IO path, drbdsetup / netlink process context */
     new_net_conf = kzalloc(sizeof(*new_net_conf), GFP_KERNEL);
     if (!new_net_conf) {
         retcode = ERR_NOMEM;
         goto fail;
     }
 
     set_net_conf_defaults(new_net_conf);
 
     err = net_conf_from_attrs(new_net_conf, info);
     if (err && err != -ENOMSG) {
         retcode = ERR_MANDATORY_TAG;
         drbd_msg_put_info(adm_ctx.reply_skb, from_attrs_err_to_txt(err));
         goto fail;
     }
 
     retcode = check_net_options(connection, new_net_conf);
     if (retcode != NO_ERROR)
         goto fail;
 
     retcode = alloc_crypto(&crypto, new_net_conf);
     if (retcode != NO_ERROR)
         goto fail;
 
     ((char *)new_net_conf->shared_secret)[SHARED_SECRET_MAX-1] = 0;
 
     drbd_flush_workqueue(&connection->sender_work);
 
     mutex_lock(&adm_ctx.resource->conf_update);
     old_net_conf = connection->net_conf;
     if (old_net_conf) {
         retcode = ERR_NET_CONFIGURED;
         mutex_unlock(&adm_ctx.resource->conf_update);
         goto fail;
     }
     rcu_assign_pointer(connection->net_conf, new_net_conf);
 
     conn_free_crypto(connection);
     connection->cram_hmac_tfm = crypto.cram_hmac_tfm;
     connection->integrity_tfm = crypto.integrity_tfm;
     connection->csums_tfm = crypto.csums_tfm;
     connection->verify_tfm = crypto.verify_tfm;
 
     connection->my_addr_len = nla_len(adm_ctx.my_addr);
     memcpy(&connection->my_addr, nla_data(adm_ctx.my_addr), connection->my_addr_len);
     connection->peer_addr_len = nla_len(adm_ctx.peer_addr);
     memcpy(&connection->peer_addr, nla_data(adm_ctx.peer_addr), connection->peer_addr_len);
 
     idr_for_each_entry(&connection->peer_devices, peer_device, i) {
         peer_devices++;
     }
 
     connection_to_info(&connection_info, connection);
     flags = (peer_devices--) ? NOTIFY_CONTINUES : 0;
     mutex_lock(&notification_mutex);
     notify_connection_state(NULL, 0, connection, &connection_info, NOTIFY_CREATE | flags);
     idr_for_each_entry(&connection->peer_devices, peer_device, i) {
         struct peer_device_info peer_device_info;
 
         peer_device_to_info(&peer_device_info, peer_device);
         flags = (peer_devices--) ? NOTIFY_CONTINUES : 0;
         notify_peer_device_state(NULL, 0, peer_device, &peer_device_info, NOTIFY_CREATE | flags);
     }
     mutex_unlock(&notification_mutex);
     mutex_unlock(&adm_ctx.resource->conf_update);
 
     rcu_read_lock();
     idr_for_each_entry(&connection->peer_devices, peer_device, i) {
         struct drbd_device *device = peer_device->device;
         device->send_cnt = 0;
         device->recv_cnt = 0;
     }
     rcu_read_unlock();
 
     rv = conn_request_state(connection, NS(conn, C_UNCONNECTED), CS_VERBOSE);
 
     conn_reconfig_done(connection);
     mutex_unlock(&adm_ctx.resource->adm_mutex);
     drbd_adm_finish(&adm_ctx, info, rv);
     return 0;
 
 fail:
     free_crypto(&crypto);
     kfree(new_net_conf);
 
     conn_reconfig_done(connection);
     mutex_unlock(&adm_ctx.resource->adm_mutex);
 out:
     drbd_adm_finish(&adm_ctx, info, retcode);
     return 0;
 }
 
 static enum drbd_state_rv conn_try_disconnect(struct drbd_connection *connection, bool force)
 {
     enum drbd_conns cstate;
     enum drbd_state_rv rv;
 
 repeat:
     rv = conn_request_state(connection, NS(conn, C_DISCONNECTING),
             force ? CS_HARD : 0);
 
     switch (rv) {
     case SS_NOTHING_TO_DO:
         break;
     case SS_ALREADY_STANDALONE:
         return SS_SUCCESS;
     case SS_PRIMARY_NOP:
         /* Our state checking code wants to see the peer outdated. */
         rv = conn_request_state(connection, NS2(conn, C_DISCONNECTING, pdsk, D_OUTDATED), 0);
 
         if (rv == SS_OUTDATE_WO_CONN) /* lost connection before graceful disconnect succeeded */
             rv = conn_request_state(connection, NS(conn, C_DISCONNECTING), CS_VERBOSE);
 
         break;
     case SS_CW_FAILED_BY_PEER:
         spin_lock_irq(&connection->resource->req_lock);
         cstate = connection->cstate;
         spin_unlock_irq(&connection->resource->req_lock);
         if (cstate <= C_WF_CONNECTION)
             goto repeat;
         /* The peer probably wants to see us outdated. */
         rv = conn_request_state(connection, NS2(conn, C_DISCONNECTING,
                             disk, D_OUTDATED), 0);
         if (rv == SS_IS_DISKLESS || rv == SS_LOWER_THAN_OUTDATED) {
             rv = conn_request_state(connection, NS(conn, C_DISCONNECTING),
                     CS_HARD);
         }
         break;
     default:;
         /* no special handling necessary */
     }
 
     if (rv >= SS_SUCCESS) {
         enum drbd_state_rv rv2;
         /* No one else can reconfigure the network while I am here.
          * The state handling only uses drbd_thread_stop_nowait(),
          * we want to really wait here until the receiver is no more.
          */
         drbd_thread_stop(&connection->receiver);
 
         /* Race breaker.  This additional state change request may be
          * necessary, if this was a forced disconnect during a receiver
          * restart.  We may have "killed" the receiver thread just
          * after drbd_receiver() returned.  Typically, we should be
          * C_STANDALONE already, now, and this becomes a no-op.
          */
         rv2 = conn_request_state(connection, NS(conn, C_STANDALONE),
                 CS_VERBOSE | CS_HARD);
         if (rv2 < SS_SUCCESS)
             drbd_err(connection,
                 "unexpected rv2=%d in conn_try_disconnect()\n",
                 rv2);
         /* Unlike in DRBD 9, the state engine has generated
          * NOTIFY_DESTROY events before clearing connection->net_conf. */
     }
     return rv;
 }
 
 int drbd_adm_disconnect(struct sk_buff *skb, struct genl_info *info)
 {
     struct drbd_config_context adm_ctx;
     struct disconnect_parms parms;
     struct drbd_connection *connection;
     enum drbd_state_rv rv;
     enum drbd_ret_code retcode;
     int err;
 
     retcode = drbd_adm_prepare(&adm_ctx, skb, info, DRBD_ADM_NEED_CONNECTION);
     if (!adm_ctx.reply_skb)
         return retcode;
     if (retcode != NO_ERROR)
         goto fail;
 
     connection = adm_ctx.connection;
     memset(&parms, 0, sizeof(parms));
     if (info->attrs[DRBD_NLA_DISCONNECT_PARMS]) {
         err = disconnect_parms_from_attrs(&parms, info);
         if (err) {
             retcode = ERR_MANDATORY_TAG;
             drbd_msg_put_info(adm_ctx.reply_skb, from_attrs_err_to_txt(err));
             goto fail;
         }
     }
 
     mutex_lock(&adm_ctx.resource->adm_mutex);
     rv = conn_try_disconnect(connection, parms.force_disconnect);
     mutex_unlock(&adm_ctx.resource->adm_mutex);
     if (rv < SS_SUCCESS) {
         drbd_adm_finish(&adm_ctx, info, rv);
         return 0;
     }
     retcode = NO_ERROR;
  fail:
     drbd_adm_finish(&adm_ctx, info, retcode);
     return 0;
 }
 
 void resync_after_online_grow(struct drbd_device *device)
 {
     int iass; /* I am sync source */
 
     drbd_info(device, "Resync of new storage after online grow\n");
     if (device->state.role != device->state.peer)
         iass = (device->state.role == R_PRIMARY);
     else
         iass = test_bit(RESOLVE_CONFLICTS, &first_peer_device(device)->connection->flags);
 
     if (iass)
         drbd_start_resync(device, C_SYNC_SOURCE);
     else
         _drbd_request_state(device, NS(conn, C_WF_SYNC_UUID), CS_VERBOSE + CS_SERIALIZE);
 }
 
 int drbd_adm_resize(struct sk_buff *skb, struct genl_info *info)
 {
     struct drbd_config_context adm_ctx;
     struct disk_conf *old_disk_conf, *new_disk_conf = NULL;
     struct resize_parms rs;
     struct drbd_device *device;
     enum drbd_ret_code retcode;
     enum determine_dev_size dd;
     bool change_al_layout = false;
     enum dds_flags ddsf;
     sector_t u_size;
     int err;
 
     retcode = drbd_adm_prepare(&adm_ctx, skb, info, DRBD_ADM_NEED_MINOR);
     if (!adm_ctx.reply_skb)
         return retcode;
     if (retcode != NO_ERROR)
         goto finish;
 
     mutex_lock(&adm_ctx.resource->adm_mutex);
     device = adm_ctx.device;
     if (!get_ldev(device)) {
         retcode = ERR_NO_DISK;
         goto fail;
     }
 
     memset(&rs, 0, sizeof(struct resize_parms));
     rs.al_stripes = device->ldev->md.al_stripes;
     rs.al_stripe_size = device->ldev->md.al_stripe_size_4k * 4;
     if (info->attrs[DRBD_NLA_RESIZE_PARMS]) {
         err = resize_parms_from_attrs(&rs, info);
         if (err) {
             retcode = ERR_MANDATORY_TAG;
             drbd_msg_put_info(adm_ctx.reply_skb, from_attrs_err_to_txt(err));
             goto fail_ldev;
         }
     }
 
     if (device->state.conn > C_CONNECTED) {
         retcode = ERR_RESIZE_RESYNC;
         goto fail_ldev;
     }
 
     if (device->state.role == R_SECONDARY &&
         device->state.peer == R_SECONDARY) {
         retcode = ERR_NO_PRIMARY;
         goto fail_ldev;
     }
 
     if (rs.no_resync && first_peer_device(device)->connection->agreed_pro_version < 93) {
         retcode = ERR_NEED_APV_93;
         goto fail_ldev;
     }
 
     rcu_read_lock();
     u_size = rcu_dereference(device->ldev->disk_conf)->disk_size;
     rcu_read_unlock();
     if (u_size != (sector_t)rs.resize_size) {
         new_disk_conf = kmalloc(sizeof(struct disk_conf), GFP_KERNEL);
         if (!new_disk_conf) {
             retcode = ERR_NOMEM;
             goto fail_ldev;
         }
     }
 
     if (device->ldev->md.al_stripes != rs.al_stripes ||
         device->ldev->md.al_stripe_size_4k != rs.al_stripe_size / 4) {
         u32 al_size_k = rs.al_stripes * rs.al_stripe_size;
 
         if (al_size_k > (16 * 1024 * 1024)) {
             retcode = ERR_MD_LAYOUT_TOO_BIG;
             goto fail_ldev;
         }
 
         if (al_size_k < MD_32kB_SECT/2) {
             retcode = ERR_MD_LAYOUT_TOO_SMALL;
             goto fail_ldev;
         }
 
         if (device->state.conn != C_CONNECTED && !rs.resize_force) {
             retcode = ERR_MD_LAYOUT_CONNECTED;
             goto fail_ldev;
         }
 
         change_al_layout = true;
     }
 
     if (device->ldev->known_size != drbd_get_capacity(device->ldev->backing_bdev))
         device->ldev->known_size = drbd_get_capacity(device->ldev->backing_bdev);
 
     if (new_disk_conf) {
         mutex_lock(&device->resource->conf_update);
         old_disk_conf = device->ldev->disk_conf;
         *new_disk_conf = *old_disk_conf;
         new_disk_conf->disk_size = (sector_t)rs.resize_size;
         rcu_assign_pointer(device->ldev->disk_conf, new_disk_conf);
         mutex_unlock(&device->resource->conf_update);
         kvfree_rcu(old_disk_conf);
         new_disk_conf = NULL;
     }
 
     ddsf = (rs.resize_force ? DDSF_FORCED : 0) | (rs.no_resync ? DDSF_NO_RESYNC : 0);
     dd = drbd_determine_dev_size(device, ddsf, change_al_layout ? &rs : NULL);
     drbd_md_sync(device);
     put_ldev(device);
     if (dd == DS_ERROR) {
         retcode = ERR_NOMEM_BITMAP;
         goto fail;
     } else if (dd == DS_ERROR_SPACE_MD) {
         retcode = ERR_MD_LAYOUT_NO_FIT;
         goto fail;
     } else if (dd == DS_ERROR_SHRINK) {
         retcode = ERR_IMPLICIT_SHRINK;
         goto fail;
     }
 
     if (device->state.conn == C_CONNECTED) {
         if (dd == DS_GREW)
             set_bit(RESIZE_PENDING, &device->flags);
 
         drbd_send_uuids(first_peer_device(device));
         drbd_send_sizes(first_peer_device(device), 1, ddsf);
     }
 
  fail:
     mutex_unlock(&adm_ctx.resource->adm_mutex);
  finish:
     drbd_adm_finish(&adm_ctx, info, retcode);
     return 0;
 
  fail_ldev:
     put_ldev(device);
     kfree(new_disk_conf);
     goto fail;
 }
 
 int drbd_adm_resource_opts(struct sk_buff *skb, struct genl_info *info)
 {
     struct drbd_config_context adm_ctx;
     enum drbd_ret_code retcode;
     struct res_opts res_opts;
     int err;
 
     retcode = drbd_adm_prepare(&adm_ctx, skb, info, DRBD_ADM_NEED_RESOURCE);
     if (!adm_ctx.reply_skb)
         return retcode;
     if (retcode != NO_ERROR)
         goto fail;
 
     res_opts = adm_ctx.resource->res_opts;
     if (should_set_defaults(info))
         set_res_opts_defaults(&res_opts);
 
     err = res_opts_from_attrs(&res_opts, info);
     if (err && err != -ENOMSG) {
         retcode = ERR_MANDATORY_TAG;
         drbd_msg_put_info(adm_ctx.reply_skb, from_attrs_err_to_txt(err));
         goto fail;
     }
 
     mutex_lock(&adm_ctx.resource->adm_mutex);
     err = set_resource_options(adm_ctx.resource, &res_opts);
     if (err) {
         retcode = ERR_INVALID_REQUEST;
         if (err == -ENOMEM)
             retcode = ERR_NOMEM;
     }
     mutex_unlock(&adm_ctx.resource->adm_mutex);
 
 fail:
     drbd_adm_finish(&adm_ctx, info, retcode);
     return 0;
 }
 
 int drbd_adm_invalidate(struct sk_buff *skb, struct genl_info *info)
 {
     struct drbd_config_context adm_ctx;
     struct drbd_device *device;
     int retcode; /* enum drbd_ret_code rsp. enum drbd_state_rv */
 
     retcode = drbd_adm_prepare(&adm_ctx, skb, info, DRBD_ADM_NEED_MINOR);
     if (!adm_ctx.reply_skb)
         return retcode;
     if (retcode != NO_ERROR)
         goto out;
 
     device = adm_ctx.device;
     if (!get_ldev(device)) {
         retcode = ERR_NO_DISK;
         goto out;
     }
 
     mutex_lock(&adm_ctx.resource->adm_mutex);
 
     /* If there is still bitmap IO pending, probably because of a previous
      * resync just being finished, wait for it before requesting a new resync.
      * Also wait for it's after_state_ch(). */
     drbd_suspend_io(device);
     wait_event(device->misc_wait, !test_bit(BITMAP_IO, &device->flags));
     drbd_flush_workqueue(&first_peer_device(device)->connection->sender_work);
 
     /* If we happen to be C_STANDALONE R_SECONDARY, just change to
      * D_INCONSISTENT, and set all bits in the bitmap.  Otherwise,
      * try to start a resync handshake as sync target for full sync.
      */
     if (device->state.conn == C_STANDALONE && device->state.role == R_SECONDARY) {
         retcode = drbd_request_state(device, NS(disk, D_INCONSISTENT));
         if (retcode >= SS_SUCCESS) {
             if (drbd_bitmap_io(device, &drbd_bmio_set_n_write,
                 "set_n_write from invalidate", BM_LOCKED_MASK))
                 retcode = ERR_IO_MD_DISK;
         }
     } else
         retcode = drbd_request_state(device, NS(conn, C_STARTING_SYNC_T));
     drbd_resume_io(device);
     mutex_unlock(&adm_ctx.resource->adm_mutex);
     put_ldev(device);
 out:
     drbd_adm_finish(&adm_ctx, info, retcode);
     return 0;
 }
 
 static int drbd_adm_simple_request_state(struct sk_buff *skb, struct genl_info *info,
         union drbd_state mask, union drbd_state val)
 {
     struct drbd_config_context adm_ctx;
     enum drbd_ret_code retcode;
 
     retcode = drbd_adm_prepare(&adm_ctx, skb, info, DRBD_ADM_NEED_MINOR);
     if (!adm_ctx.reply_skb)
         return retcode;
     if (retcode != NO_ERROR)
         goto out;
 
     mutex_lock(&adm_ctx.resource->adm_mutex);
     retcode = drbd_request_state(adm_ctx.device, mask, val);
     mutex_unlock(&adm_ctx.resource->adm_mutex);
 out:
     drbd_adm_finish(&adm_ctx, info, retcode);
     return 0;
 }
 
 static int drbd_bmio_set_susp_al(struct drbd_device *device) __must_hold(local)
 {
     int rv;
 
     rv = drbd_bmio_set_n_write(device);
     drbd_suspend_al(device);
     return rv;
 }
 
 int drbd_adm_invalidate_peer(struct sk_buff *skb, struct genl_info *info)
 {
     struct drbd_config_context adm_ctx;
     int retcode; /* drbd_ret_code, drbd_state_rv */
     struct drbd_device *device;
 
     retcode = drbd_adm_prepare(&adm_ctx, skb, info, DRBD_ADM_NEED_MINOR);
     if (!adm_ctx.reply_skb)
         return retcode;
     if (retcode != NO_ERROR)
         goto out;
 
     device = adm_ctx.device;
     if (!get_ldev(device)) {
         retcode = ERR_NO_DISK;
         goto out;
     }
 
     mutex_lock(&adm_ctx.resource->adm_mutex);
 
     /* If there is still bitmap IO pending, probably because of a previous
      * resync just being finished, wait for it before requesting a new resync.
      * Also wait for it's after_state_ch(). */
     drbd_suspend_io(device);
     wait_event(device->misc_wait, !test_bit(BITMAP_IO, &device->flags));
     drbd_flush_workqueue(&first_peer_device(device)->connection->sender_work);
 
     /* If we happen to be C_STANDALONE R_PRIMARY, just set all bits
      * in the bitmap.  Otherwise, try to start a resync handshake
      * as sync source for full sync.
      */
     if (device->state.conn == C_STANDALONE && device->state.role == R_PRIMARY) {
         /* The peer will get a resync upon connect anyways. Just make that
            into a full resync. */
         retcode = drbd_request_state(device, NS(pdsk, D_INCONSISTENT));
         if (retcode >= SS_SUCCESS) {
             if (drbd_bitmap_io(device, &drbd_bmio_set_susp_al,
                 "set_n_write from invalidate_peer",
                 BM_LOCKED_SET_ALLOWED))
                 retcode = ERR_IO_MD_DISK;
         }
     } else
         retcode = drbd_request_state(device, NS(conn, C_STARTING_SYNC_S));
     drbd_resume_io(device);
     mutex_unlock(&adm_ctx.resource->adm_mutex);
     put_ldev(device);
 out:
     drbd_adm_finish(&adm_ctx, info, retcode);
     return 0;
 }
 
 int drbd_adm_pause_sync(struct sk_buff *skb, struct genl_info *info)
 {
     struct drbd_config_context adm_ctx;
     enum drbd_ret_code retcode;
 
     retcode = drbd_adm_prepare(&adm_ctx, skb, info, DRBD_ADM_NEED_MINOR);
     if (!adm_ctx.reply_skb)
         return retcode;
     if (retcode != NO_ERROR)
         goto out;
 
     mutex_lock(&adm_ctx.resource->adm_mutex);
     if (drbd_request_state(adm_ctx.device, NS(user_isp, 1)) == SS_NOTHING_TO_DO)
         retcode = ERR_PAUSE_IS_SET;
     mutex_unlock(&adm_ctx.resource->adm_mutex);
 out:
     drbd_adm_finish(&adm_ctx, info, retcode);
     return 0;
 }
 
 int drbd_adm_resume_sync(struct sk_buff *skb, struct genl_info *info)
 {
     struct drbd_config_context adm_ctx;
     union drbd_dev_state s;
     enum drbd_ret_code retcode;
 
     retcode = drbd_adm_prepare(&adm_ctx, skb, info, DRBD_ADM_NEED_MINOR);
     if (!adm_ctx.reply_skb)
         return retcode;
     if (retcode != NO_ERROR)
         goto out;
 
     mutex_lock(&adm_ctx.resource->adm_mutex);
     if (drbd_request_state(adm_ctx.device, NS(user_isp, 0)) == SS_NOTHING_TO_DO) {
         s = adm_ctx.device->state;
         if (s.conn == C_PAUSED_SYNC_S || s.conn == C_PAUSED_SYNC_T) {
             retcode = s.aftr_isp ? ERR_PIC_AFTER_DEP :
                   s.peer_isp ? ERR_PIC_PEER_DEP : ERR_PAUSE_IS_CLEAR;
         } else {
             retcode = ERR_PAUSE_IS_CLEAR;
         }
     }
     mutex_unlock(&adm_ctx.resource->adm_mutex);
 out:
     drbd_adm_finish(&adm_ctx, info, retcode);
     return 0;
 }
 
 int drbd_adm_suspend_io(struct sk_buff *skb, struct genl_info *info)
 {
     return drbd_adm_simple_request_state(skb, info, NS(susp, 1));
 }
 
 int drbd_adm_resume_io(struct sk_buff *skb, struct genl_info *info)
 {
     struct drbd_config_context adm_ctx;
     struct drbd_device *device;
     int retcode; /* enum drbd_ret_code rsp. enum drbd_state_rv */
 
     retcode = drbd_adm_prepare(&adm_ctx, skb, info, DRBD_ADM_NEED_MINOR);
     if (!adm_ctx.reply_skb)
         return retcode;
     if (retcode != NO_ERROR)
         goto out;
 
     mutex_lock(&adm_ctx.resource->adm_mutex);
     device = adm_ctx.device;
     if (test_bit(NEW_CUR_UUID, &device->flags)) {
         if (get_ldev_if_state(device, D_ATTACHING)) {
             drbd_uuid_new_current(device);
             put_ldev(device);
         } else {
             /* This is effectively a multi-stage "forced down".
              * The NEW_CUR_UUID bit is supposedly only set, if we
              * lost the replication connection, and are configured
              * to freeze IO and wait for some fence-peer handler.
              * So we still don't have a replication connection.
              * And now we don't have a local disk either.  After
              * resume, we will fail all pending and new IO, because
              * we don't have any data anymore.  Which means we will
              * eventually be able to terminate all users of this
              * device, and then take it down.  By bumping the
              * "effective" data uuid, we make sure that you really
              * need to tear down before you reconfigure, we will
              * the refuse to re-connect or re-attach (because no
              * matching real data uuid exists).
              */
             u64 val;
             get_random_bytes(&val, sizeof(u64));
             drbd_set_ed_uuid(device, val);
             drbd_warn(device, "Resumed without access to data; please tear down before attempting to re-configure.\n");
         }
         clear_bit(NEW_CUR_UUID, &device->flags);
     }
     drbd_suspend_io(device);
     retcode = drbd_request_state(device, NS3(susp, 0, susp_nod, 0, susp_fen, 0));
     if (retcode == SS_SUCCESS) {
         if (device->state.conn < C_CONNECTED)
             tl_clear(first_peer_device(device)->connection);
         if (device->state.disk == D_DISKLESS || device->state.disk == D_FAILED)
             tl_restart(first_peer_device(device)->connection, FAIL_FROZEN_DISK_IO);
     }
     drbd_resume_io(device);
     mutex_unlock(&adm_ctx.resource->adm_mutex);
 out:
     drbd_adm_finish(&adm_ctx, info, retcode);
     return 0;
 }
 
 int drbd_adm_outdate(struct sk_buff *skb, struct genl_info *info)
 {
     return drbd_adm_simple_request_state(skb, info, NS(disk, D_OUTDATED));
 }
 
 static int nla_put_drbd_cfg_context(struct sk_buff *skb,
                     struct drbd_resource *resource,
                     struct drbd_connection *connection,
                     struct drbd_device *device)
 {
     struct nlattr *nla;
     nla = nla_nest_start_noflag(skb, DRBD_NLA_CFG_CONTEXT);
     if (!nla)
         goto nla_put_failure;
     if (device &&
         nla_put_u32(skb, T_ctx_volume, device->vnr))
         goto nla_put_failure;
     if (nla_put_string(skb, T_ctx_resource_name, resource->name))
         goto nla_put_failure;
     if (connection) {
         if (connection->my_addr_len &&
             nla_put(skb, T_ctx_my_addr, connection->my_addr_len, &connection->my_addr))
             goto nla_put_failure;
         if (connection->peer_addr_len &&
             nla_put(skb, T_ctx_peer_addr, connection->peer_addr_len, &connection->peer_addr))
             goto nla_put_failure;
     }
     nla_nest_end(skb, nla);
     return 0;
 
 nla_put_failure:
     if (nla)
         nla_nest_cancel(skb, nla);
     return -EMSGSIZE;
 }
 
 /*
  * The generic netlink dump callbacks are called outside the genl_lock(), so
  * they cannot use the simple attribute parsing code which uses global
  * attribute tables.
  */
 static struct nlattr *find_cfg_context_attr(const struct nlmsghdr *nlh, int attr)
 {
     const unsigned hdrlen = GENL_HDRLEN + GENL_MAGIC_FAMILY_HDRSZ;
     const int maxtype = ARRAY_SIZE(drbd_cfg_context_nl_policy) - 1;
     struct nlattr *nla;
 
     nla = nla_find(nlmsg_attrdata(nlh, hdrlen), nlmsg_attrlen(nlh, hdrlen),
                DRBD_NLA_CFG_CONTEXT);
     if (!nla)
         return NULL;
     return drbd_nla_find_nested(maxtype, nla, __nla_type(attr));
 }
 
 static void resource_to_info(struct resource_info *, struct drbd_resource *);
 
 int drbd_adm_dump_resources(struct sk_buff *skb, struct netlink_callback *cb)
 {
     struct drbd_genlmsghdr *dh;
     struct drbd_resource *resource;
     struct resource_info resource_info;
     struct resource_statistics resource_statistics;
     int err;
 
     rcu_read_lock();
     if (cb->args[0]) {
         for_each_resource_rcu(resource, &drbd_resources)
             if (resource == (struct drbd_resource *)cb->args[0])
                 goto found_resource;
         err = 0;  /* resource was probably deleted */
         goto out;
     }
     resource = list_entry(&drbd_resources,
                   struct drbd_resource, resources);
 
 found_resource:
     list_for_each_entry_continue_rcu(resource, &drbd_resources, resources) {
         goto put_result;
     }
     err = 0;
     goto out;
 
 put_result:
     dh = genlmsg_put(skb, NETLINK_CB(cb->skb).portid,
             cb->nlh->nlmsg_seq, &drbd_genl_family,
             NLM_F_MULTI, DRBD_ADM_GET_RESOURCES);
     err = -ENOMEM;
     if (!dh)
         goto out;
     dh->minor = -1U;
     dh->ret_code = NO_ERROR;
     err = nla_put_drbd_cfg_context(skb, resource, NULL, NULL);
     if (err)
         goto out;
     err = res_opts_to_skb(skb, &resource->res_opts, !capable(CAP_SYS_ADMIN));
     if (err)
         goto out;
     resource_to_info(&resource_info, resource);
     err = resource_info_to_skb(skb, &resource_info, !capable(CAP_SYS_ADMIN));
     if (err)
         goto out;
     resource_statistics.res_stat_write_ordering = resource->write_ordering;
     err = resource_statistics_to_skb(skb, &resource_statistics, !capable(CAP_SYS_ADMIN));
     if (err)
         goto out;
     cb->args[0] = (long)resource;
     genlmsg_end(skb, dh);
     err = 0;
 
 out:
     rcu_read_unlock();
     if (err)
         return err;
     return skb->len;
 }
 
 static void device_to_statistics(struct device_statistics *s,
                  struct drbd_device *device)
 {
     memset(s, 0, sizeof(*s));
     s->dev_upper_blocked = !may_inc_ap_bio(device);
     if (get_ldev(device)) {
         struct drbd_md *md = &device->ldev->md;
         u64 *history_uuids = (u64 *)s->history_uuids;
         int n;
 
         spin_lock_irq(&md->uuid_lock);
         s->dev_current_uuid = md->uuid[UI_CURRENT];
         BUILD_BUG_ON(sizeof(s->history_uuids) < UI_HISTORY_END - UI_HISTORY_START + 1);
         for (n = 0; n < UI_HISTORY_END - UI_HISTORY_START + 1; n++)
             history_uuids[n] = md->uuid[UI_HISTORY_START + n];
         for (; n < HISTORY_UUIDS; n++)
             history_uuids[n] = 0;
         s->history_uuids_len = HISTORY_UUIDS;
         spin_unlock_irq(&md->uuid_lock);
 
         s->dev_disk_flags = md->flags;
         put_ldev(device);
     }
     s->dev_size = get_capacity(device->vdisk);
     s->dev_read = device->read_cnt;
     s->dev_write = device->writ_cnt;
     s->dev_al_writes = device->al_writ_cnt;
     s->dev_bm_writes = device->bm_writ_cnt;
     s->dev_upper_pending = atomic_read(&device->ap_bio_cnt);
     s->dev_lower_pending = atomic_read(&device->local_cnt);
     s->dev_al_suspended = test_bit(AL_SUSPENDED, &device->flags);
     s->dev_exposed_data_uuid = device->ed_uuid;
 }
 
 static int put_resource_in_arg0(struct netlink_callback *cb, int holder_nr)
 {
     if (cb->args[0]) {
         struct drbd_resource *resource =
             (struct drbd_resource *)cb->args[0];
         kref_put(&resource->kref, drbd_destroy_resource);
     }
 
     return 0;
 }
 
 int drbd_adm_dump_devices_done(struct netlink_callback *cb) {
     return put_resource_in_arg0(cb, 7);
 }
 
 static void device_to_info(struct device_info *, struct drbd_device *);
 
 int drbd_adm_dump_devices(struct sk_buff *skb, struct netlink_callback *cb)
 {
     struct nlattr *resource_filter;
     struct drbd_resource *resource;
     struct drbd_device *device;
     int minor, err, retcode;
     struct drbd_genlmsghdr *dh;
     struct device_info device_info;
     struct device_statistics device_statistics;
     struct idr *idr_to_search;
 
     resource = (struct drbd_resource *)cb->args[0];
     if (!cb->args[0] && !cb->args[1]) {
         resource_filter = find_cfg_context_attr(cb->nlh, T_ctx_resource_name);
         if (resource_filter) {
             retcode = ERR_RES_NOT_KNOWN;
             resource = drbd_find_resource(nla_data(resource_filter));
             if (!resource)
                 goto put_result;
             cb->args[0] = (long)resource;
         }
     }
 
     rcu_read_lock();
     minor = cb->args[1];
     idr_to_search = resource ? &resource->devices : &drbd_devices;
     device = idr_get_next(idr_to_search, &minor);
     if (!device) {
         err = 0;
         goto out;
     }
     idr_for_each_entry_continue(idr_to_search, device, minor) {
         retcode = NO_ERROR;
         goto put_result;  /* only one iteration */
     }
     err = 0;
     goto out;  /* no more devices */
 
 put_result:
     dh = genlmsg_put(skb, NETLINK_CB(cb->skb).portid,
             cb->nlh->nlmsg_seq, &drbd_genl_family,
             NLM_F_MULTI, DRBD_ADM_GET_DEVICES);
     err = -ENOMEM;
     if (!dh)
         goto out;
     dh->ret_code = retcode;
     dh->minor = -1U;
     if (retcode == NO_ERROR) {
         dh->minor = device->minor;
         err = nla_put_drbd_cfg_context(skb, device->resource, NULL, device);
         if (err)
             goto out;
         if (get_ldev(device)) {
             struct disk_conf *disk_conf =
                 rcu_dereference(device->ldev->disk_conf);
 
             err = disk_conf_to_skb(skb, disk_conf, !capable(CAP_SYS_ADMIN));
             put_ldev(device);
             if (err)
                 goto out;
         }
         device_to_info(&device_info, device);
         err = device_info_to_skb(skb, &device_info, !capable(CAP_SYS_ADMIN));
         if (err)
             goto out;
 
         device_to_statistics(&device_statistics, device);
         err = device_statistics_to_skb(skb, &device_statistics, !capable(CAP_SYS_ADMIN));
         if (err)
             goto out;
         cb->args[1] = minor + 1;
     }
     genlmsg_end(skb, dh);
     err = 0;
 
 out:
     rcu_read_unlock();
     if (err)
         return err;
     return skb->len;
 }
 
 int drbd_adm_dump_connections_done(struct netlink_callback *cb)
 {
     return put_resource_in_arg0(cb, 6);
 }
 
 enum { SINGLE_RESOURCE, ITERATE_RESOURCES };
 
 int drbd_adm_dump_connections(struct sk_buff *skb, struct netlink_callback *cb)
 {
     struct nlattr *resource_filter;
     struct drbd_resource *resource = NULL, *next_resource;
     struct drbd_connection *connection;
     int err = 0, retcode;
     struct drbd_genlmsghdr *dh;
     struct connection_info connection_info;
     struct connection_statistics connection_statistics;
 
     rcu_read_lock();
     resource = (struct drbd_resource *)cb->args[0];
     if (!cb->args[0]) {
         resource_filter = find_cfg_context_attr(cb->nlh, T_ctx_resource_name);
         if (resource_filter) {
             retcode = ERR_RES_NOT_KNOWN;
             resource = drbd_find_resource(nla_data(resource_filter));
             if (!resource)
                 goto put_result;
             cb->args[0] = (long)resource;
             cb->args[1] = SINGLE_RESOURCE;
         }
     }
     if (!resource) {
         if (list_empty(&drbd_resources))
             goto out;
         resource = list_first_entry(&drbd_resources, struct drbd_resource, resources);
         kref_get(&resource->kref);
         cb->args[0] = (long)resource;
         cb->args[1] = ITERATE_RESOURCES;
     }
 
     next_resource:
     rcu_read_unlock();
     mutex_lock(&resource->conf_update);
     rcu_read_lock();
     if (cb->args[2]) {
         for_each_connection_rcu(connection, resource)
             if (connection == (struct drbd_connection *)cb->args[2])
                 goto found_connection;
         /* connection was probably deleted */
         goto no_more_connections;
     }
     connection = list_entry(&resource->connections, struct drbd_connection, connections);
 
 found_connection:
     list_for_each_entry_continue_rcu(connection, &resource->connections, connections) {
         if (!has_net_conf(connection))
             continue;
         retcode = NO_ERROR;
         goto put_result;  /* only one iteration */
     }
 
 no_more_connections:
     if (cb->args[1] == ITERATE_RESOURCES) {
         for_each_resource_rcu(next_resource, &drbd_resources) {
             if (next_resource == resource)
                 goto found_resource;
         }
         /* resource was probably deleted */
     }
     goto out;
 
 found_resource:
     list_for_each_entry_continue_rcu(next_resource, &drbd_resources, resources) {
         mutex_unlock(&resource->conf_update);
         kref_put(&resource->kref, drbd_destroy_resource);
         resource = next_resource;
         kref_get(&resource->kref);
         cb->args[0] = (long)resource;
         cb->args[2] = 0;
         goto next_resource;
     }
     goto out;  /* no more resources */
 
 put_result:
     dh = genlmsg_put(skb, NETLINK_CB(cb->skb).portid,
             cb->nlh->nlmsg_seq, &drbd_genl_family,
             NLM_F_MULTI, DRBD_ADM_GET_CONNECTIONS);
     err = -ENOMEM;
     if (!dh)
         goto out;
     dh->ret_code = retcode;
     dh->minor = -1U;
     if (retcode == NO_ERROR) {
         struct net_conf *net_conf;
 
         err = nla_put_drbd_cfg_context(skb, resource, connection, NULL);
         if (err)
             goto out;
         net_conf = rcu_dereference(connection->net_conf);
         if (net_conf) {
             err = net_conf_to_skb(skb, net_conf, !capable(CAP_SYS_ADMIN));
             if (err)
                 goto out;
         }
         connection_to_info(&connection_info, connection);
         err = connection_info_to_skb(skb, &connection_info, !capable(CAP_SYS_ADMIN));
         if (err)
             goto out;
         connection_statistics.conn_congested = test_bit(NET_CONGESTED, &connection->flags);
         err = connection_statistics_to_skb(skb, &connection_statistics, !capable(CAP_SYS_ADMIN));
         if (err)
             goto out;
         cb->args[2] = (long)connection;
     }
     genlmsg_end(skb, dh);
     err = 0;
 
 out:
     rcu_read_unlock();
     if (resource)
         mutex_unlock(&resource->conf_update);
     if (err)
         return err;
     return skb->len;
 }
 
 enum mdf_peer_flag {
     MDF_PEER_CONNECTED =    1 << 0,
     MDF_PEER_OUTDATED = 1 << 1,
     MDF_PEER_FENCING =  1 << 2,
     MDF_PEER_FULL_SYNC =    1 << 3,
 };
 
 static void peer_device_to_statistics(struct peer_device_statistics *s,
                       struct drbd_peer_device *peer_device)
 {
     struct drbd_device *device = peer_device->device;
 
     memset(s, 0, sizeof(*s));
     s->peer_dev_received = device->recv_cnt;
     s->peer_dev_sent = device->send_cnt;
     s->peer_dev_pending = atomic_read(&device->ap_pending_cnt) +
                   atomic_read(&device->rs_pending_cnt);
     s->peer_dev_unacked = atomic_read(&device->unacked_cnt);
     s->peer_dev_out_of_sync = drbd_bm_total_weight(device) << (BM_BLOCK_SHIFT - 9);
     s->peer_dev_resync_failed = device->rs_failed << (BM_BLOCK_SHIFT - 9);
     if (get_ldev(device)) {
         struct drbd_md *md = &device->ldev->md;
 
         spin_lock_irq(&md->uuid_lock);
         s->peer_dev_bitmap_uuid = md->uuid[UI_BITMAP];
         spin_unlock_irq(&md->uuid_lock);
         s->peer_dev_flags =
             (drbd_md_test_flag(device->ldev, MDF_CONNECTED_IND) ?
                 MDF_PEER_CONNECTED : 0) +
             (drbd_md_test_flag(device->ldev, MDF_CONSISTENT) &&
              !drbd_md_test_flag(device->ldev, MDF_WAS_UP_TO_DATE) ?
                 MDF_PEER_OUTDATED : 0) +
             /* FIXME: MDF_PEER_FENCING? */
             (drbd_md_test_flag(device->ldev, MDF_FULL_SYNC) ?
                 MDF_PEER_FULL_SYNC : 0);
         put_ldev(device);
     }
 }
 
 int drbd_adm_dump_peer_devices_done(struct netlink_callback *cb)
 {
     return put_resource_in_arg0(cb, 9);
 }
 
 int drbd_adm_dump_peer_devices(struct sk_buff *skb, struct netlink_callback *cb)
 {
     struct nlattr *resource_filter;
     struct drbd_resource *resource;
     struct drbd_device *device;
     struct drbd_peer_device *peer_device = NULL;
     int minor, err, retcode;
     struct drbd_genlmsghdr *dh;
     struct idr *idr_to_search;
 
     resource = (struct drbd_resource *)cb->args[0];
     if (!cb->args[0] && !cb->args[1]) {
         resource_filter = find_cfg_context_attr(cb->nlh, T_ctx_resource_name);
         if (resource_filter) {
             retcode = ERR_RES_NOT_KNOWN;
             resource = drbd_find_resource(nla_data(resource_filter));
             if (!resource)
                 goto put_result;
         }
         cb->args[0] = (long)resource;
     }
 
     rcu_read_lock();
     minor = cb->args[1];
     idr_to_search = resource ? &resource->devices : &drbd_devices;
     device = idr_find(idr_to_search, minor);
     if (!device) {
 next_device:
         minor++;
         cb->args[2] = 0;
         device = idr_get_next(idr_to_search, &minor);
         if (!device) {
             err = 0;
             goto out;
         }
     }
     if (cb->args[2]) {
         for_each_peer_device(peer_device, device)
             if (peer_device == (struct drbd_peer_device *)cb->args[2])
                 goto found_peer_device;
         /* peer device was probably deleted */
         goto next_device;
     }
     /* Make peer_device point to the list head (not the first entry). */
     peer_device = list_entry(&device->peer_devices, struct drbd_peer_device, peer_devices);
 
 found_peer_device:
     list_for_each_entry_continue_rcu(peer_device, &device->peer_devices, peer_devices) {
         if (!has_net_conf(peer_device->connection))
             continue;
         retcode = NO_ERROR;
         goto put_result;  /* only one iteration */
     }
     goto next_device;
 
 put_result:
     dh = genlmsg_put(skb, NETLINK_CB(cb->skb).portid,
             cb->nlh->nlmsg_seq, &drbd_genl_family,
             NLM_F_MULTI, DRBD_ADM_GET_PEER_DEVICES);
     err = -ENOMEM;
     if (!dh)
         goto out;
     dh->ret_code = retcode;
     dh->minor = -1U;
     if (retcode == NO_ERROR) {
         struct peer_device_info peer_device_info;
         struct peer_device_statistics peer_device_statistics;
 
         dh->minor = minor;
         err = nla_put_drbd_cfg_context(skb, device->resource, peer_device->connection, device);
         if (err)
             goto out;
         peer_device_to_info(&peer_device_info, peer_device);
         err = peer_device_info_to_skb(skb, &peer_device_info, !capable(CAP_SYS_ADMIN));
         if (err)
             goto out;
         peer_device_to_statistics(&peer_device_statistics, peer_device);
         err = peer_device_statistics_to_skb(skb, &peer_device_statistics, !capable(CAP_SYS_ADMIN));
         if (err)
             goto out;
         cb->args[1] = minor;
         cb->args[2] = (long)peer_device;
     }
     genlmsg_end(skb, dh);
     err = 0;
 
 out:
     rcu_read_unlock();
     if (err)
         return err;
     return skb->len;
 }
 /*
  * Return the connection of @resource if @resource has exactly one connection.
  */
 static struct drbd_connection *the_only_connection(struct drbd_resource *resource)
 {
     struct list_head *connections = &resource->connections;
 
     if (list_empty(connections) || connections->next->next != connections)
         return NULL;
     return list_first_entry(&resource->connections, struct drbd_connection, connections);
 }
 
 static int nla_put_status_info(struct sk_buff *skb, struct drbd_device *device,
         const struct sib_info *sib)
 {
     struct drbd_resource *resource = device->resource;
     struct state_info *si = NULL; /* for sizeof(si->member); */
     struct nlattr *nla;
     int got_ldev;
     int err = 0;
     int exclude_sensitive;
 
     /* If sib != NULL, this is drbd_bcast_event, which anyone can listen
      * to.  So we better exclude_sensitive information.
      *
      * If sib == NULL, this is drbd_adm_get_status, executed synchronously
      * in the context of the requesting user process. Exclude sensitive
      * information, unless current has superuser.
      *
      * NOTE: for drbd_adm_get_status_all(), this is a netlink dump, and
      * relies on the current implementation of netlink_dump(), which
      * executes the dump callback successively from netlink_recvmsg(),
      * always in the context of the receiving process */
     exclude_sensitive = sib || !capable(CAP_SYS_ADMIN);
 
     got_ldev = get_ldev(device);
 
     /* We need to add connection name and volume number information still.
      * Minor number is in drbd_genlmsghdr. */
     if (nla_put_drbd_cfg_context(skb, resource, the_only_connection(resource), device))
         goto nla_put_failure;
 
     if (res_opts_to_skb(skb, &device->resource->res_opts, exclude_sensitive))
         goto nla_put_failure;
 
     rcu_read_lock();
     if (got_ldev) {
         struct disk_conf *disk_conf;
 
         disk_conf = rcu_dereference(device->ldev->disk_conf);
         err = disk_conf_to_skb(skb, disk_conf, exclude_sensitive);
     }
     if (!err) {
         struct net_conf *nc;
 
         nc = rcu_dereference(first_peer_device(device)->connection->net_conf);
         if (nc)
             err = net_conf_to_skb(skb, nc, exclude_sensitive);
     }
     rcu_read_unlock();
     if (err)
         goto nla_put_failure;
 
     nla = nla_nest_start_noflag(skb, DRBD_NLA_STATE_INFO);
     if (!nla)
         goto nla_put_failure;
     if (nla_put_u32(skb, T_sib_reason, sib ? sib->sib_reason : SIB_GET_STATUS_REPLY) ||
         nla_put_u32(skb, T_current_state, device->state.i) ||
         nla_put_u64_0pad(skb, T_ed_uuid, device->ed_uuid) ||
         nla_put_u64_0pad(skb, T_capacity, get_capacity(device->vdisk)) ||
         nla_put_u64_0pad(skb, T_send_cnt, device->send_cnt) ||
         nla_put_u64_0pad(skb, T_recv_cnt, device->recv_cnt) ||
         nla_put_u64_0pad(skb, T_read_cnt, device->read_cnt) ||
         nla_put_u64_0pad(skb, T_writ_cnt, device->writ_cnt) ||
         nla_put_u64_0pad(skb, T_al_writ_cnt, device->al_writ_cnt) ||
         nla_put_u64_0pad(skb, T_bm_writ_cnt, device->bm_writ_cnt) ||
         nla_put_u32(skb, T_ap_bio_cnt, atomic_read(&device->ap_bio_cnt)) ||
         nla_put_u32(skb, T_ap_pending_cnt, atomic_read(&device->ap_pending_cnt)) ||
         nla_put_u32(skb, T_rs_pending_cnt, atomic_read(&device->rs_pending_cnt)))
         goto nla_put_failure;
 
     if (got_ldev) {
         int err;
 
         spin_lock_irq(&device->ldev->md.uuid_lock);
         err = nla_put(skb, T_uuids, sizeof(si->uuids), device->ldev->md.uuid);
         spin_unlock_irq(&device->ldev->md.uuid_lock);
 
         if (err)
             goto nla_put_failure;
 
         if (nla_put_u32(skb, T_disk_flags, device->ldev->md.flags) ||
             nla_put_u64_0pad(skb, T_bits_total, drbd_bm_bits(device)) ||
             nla_put_u64_0pad(skb, T_bits_oos,
                      drbd_bm_total_weight(device)))
             goto nla_put_failure;
         if (C_SYNC_SOURCE <= device->state.conn &&
             C_PAUSED_SYNC_T >= device->state.conn) {
             if (nla_put_u64_0pad(skb, T_bits_rs_total,
                          device->rs_total) ||
                 nla_put_u64_0pad(skb, T_bits_rs_failed,
                          device->rs_failed))
                 goto nla_put_failure;
         }
     }
 
     if (sib) {
         switch(sib->sib_reason) {
         case SIB_SYNC_PROGRESS:
         case SIB_GET_STATUS_REPLY:
             break;
         case SIB_STATE_CHANGE:
             if (nla_put_u32(skb, T_prev_state, sib->os.i) ||
                 nla_put_u32(skb, T_new_state, sib->ns.i))
                 goto nla_put_failure;
             break;
         case SIB_HELPER_POST:
             if (nla_put_u32(skb, T_helper_exit_code,
                     sib->helper_exit_code))
                 goto nla_put_failure;
             fallthrough;
         case SIB_HELPER_PRE:
             if (nla_put_string(skb, T_helper, sib->helper_name))
                 goto nla_put_failure;
             break;
         }
     }
     nla_nest_end(skb, nla);
 
     if (0)
 nla_put_failure:
         err = -EMSGSIZE;
     if (got_ldev)
         put_ldev(device);
     return err;
 }
 
 int drbd_adm_get_status(struct sk_buff *skb, struct genl_info *info)
 {
     struct drbd_config_context adm_ctx;
     enum drbd_ret_code retcode;
     int err;
 
     retcode = drbd_adm_prepare(&adm_ctx, skb, info, DRBD_ADM_NEED_MINOR);
     if (!adm_ctx.reply_skb)
         return retcode;
     if (retcode != NO_ERROR)
         goto out;
 
     err = nla_put_status_info(adm_ctx.reply_skb, adm_ctx.device, NULL);
     if (err) {
         nlmsg_free(adm_ctx.reply_skb);
         return err;
     }
 out:
     drbd_adm_finish(&adm_ctx, info, retcode);
     return 0;
 }
 
 static int get_one_status(struct sk_buff *skb, struct netlink_callback *cb)
 {
     struct drbd_device *device;
     struct drbd_genlmsghdr *dh;
     struct drbd_resource *pos = (struct drbd_resource *)cb->args[0];
     struct drbd_resource *resource = NULL;
     struct drbd_resource *tmp;
     unsigned volume = cb->args[1];
 
     /* Open coded, deferred, iteration:
      * for_each_resource_safe(resource, tmp, &drbd_resources) {
      *      connection = "first connection of resource or undefined";
      *  idr_for_each_entry(&resource->devices, device, i) {
      *    ...
      *  }
      * }
      * where resource is cb->args[0];
      * and i is cb->args[1];
      *
      * cb->args[2] indicates if we shall loop over all resources,
      * or just dump all volumes of a single resource.
      *
      * This may miss entries inserted after this dump started,
      * or entries deleted before they are reached.
      *
      * We need to make sure the device won't disappear while
      * we are looking at it, and revalidate our iterators
      * on each iteration.
      */
 
     /* synchronize with conn_create()/drbd_destroy_connection() */
     rcu_read_lock();
     /* revalidate iterator position */
     for_each_resource_rcu(tmp, &drbd_resources) {
         if (pos == NULL) {
             /* first iteration */
             pos = tmp;
             resource = pos;
             break;
         }
         if (tmp == pos) {
             resource = pos;
             break;
         }
     }
     if (resource) {
 next_resource:
         device = idr_get_next(&resource->devices, &volume);
         if (!device) {
             /* No more volumes to dump on this resource.
              * Advance resource iterator. */
             pos = list_entry_rcu(resource->resources.next,
                          struct drbd_resource, resources);
             /* Did we dump any volume of this resource yet? */
             if (volume != 0) {
                 /* If we reached the end of the list,
                  * or only a single resource dump was requested,
                  * we are done. */
                 if (&pos->resources == &drbd_resources || cb->args[2])
                     goto out;
                 volume = 0;
                 resource = pos;
                 goto next_resource;
             }
         }
 
         dh = genlmsg_put(skb, NETLINK_CB(cb->skb).portid,
                 cb->nlh->nlmsg_seq, &drbd_genl_family,
                 NLM_F_MULTI, DRBD_ADM_GET_STATUS);
         if (!dh)
             goto out;
 
         if (!device) {
             /* This is a connection without a single volume.
              * Suprisingly enough, it may have a network
              * configuration. */
             struct drbd_connection *connection;
 
             dh->minor = -1U;
             dh->ret_code = NO_ERROR;
             connection = the_only_connection(resource);
             if (nla_put_drbd_cfg_context(skb, resource, connection, NULL))
                 goto cancel;
             if (connection) {
                 struct net_conf *nc;
 
                 nc = rcu_dereference(connection->net_conf);
                 if (nc && net_conf_to_skb(skb, nc, 1) != 0)
                     goto cancel;
             }
             goto done;
         }
 
         D_ASSERT(device, device->vnr == volume);
         D_ASSERT(device, device->resource == resource);
 
         dh->minor = device_to_minor(device);
         dh->ret_code = NO_ERROR;
 
         if (nla_put_status_info(skb, device, NULL)) {
 cancel:
             genlmsg_cancel(skb, dh);
             goto out;
         }
 done:
         genlmsg_end(skb, dh);
     }
 
 out:
     rcu_read_unlock();
     /* where to start the next iteration */
     cb->args[0] = (long)pos;
     cb->args[1] = (pos == resource) ? volume + 1 : 0;
 
     /* No more resources/volumes/minors found results in an empty skb.
      * Which will terminate the dump. */
         return skb->len;
 }
 
 /*
  * Request status of all resources, or of all volumes within a single resource.
  *
  * This is a dump, as the answer may not fit in a single reply skb otherwise.
  * Which means we cannot use the family->attrbuf or other such members, because
  * dump is NOT protected by the genl_lock().  During dump, we only have access
  * to the incoming skb, and need to opencode "parsing" of the nlattr payload.
  *
  * Once things are setup properly, we call into get_one_status().
  */
 int drbd_adm_get_status_all(struct sk_buff *skb, struct netlink_callback *cb)
 {
     const unsigned hdrlen = GENL_HDRLEN + GENL_MAGIC_FAMILY_HDRSZ;
     struct nlattr *nla;
     const char *resource_name;
     struct drbd_resource *resource;
     int maxtype;
 
     /* Is this a followup call? */
     if (cb->args[0]) {
         /* ... of a single resource dump,
          * and the resource iterator has been advanced already? */
         if (cb->args[2] && cb->args[2] != cb->args[0])
             return 0; /* DONE. */
         goto dump;
     }
 
     /* First call (from netlink_dump_start).  We need to figure out
      * which resource(s) the user wants us to dump. */
     nla = nla_find(nlmsg_attrdata(cb->nlh, hdrlen),
             nlmsg_attrlen(cb->nlh, hdrlen),
             DRBD_NLA_CFG_CONTEXT);
 
     /* No explicit context given.  Dump all. */
     if (!nla)
         goto dump;
     maxtype = ARRAY_SIZE(drbd_cfg_context_nl_policy) - 1;
     nla = drbd_nla_find_nested(maxtype, nla, __nla_type(T_ctx_resource_name));
     if (IS_ERR(nla))
         return PTR_ERR(nla);
     /* context given, but no name present? */
     if (!nla)
         return -EINVAL;
     resource_name = nla_data(nla);
     if (!*resource_name)
         return -ENODEV;
     resource = drbd_find_resource(resource_name);
     if (!resource)
         return -ENODEV;
 
     kref_put(&resource->kref, drbd_destroy_resource); /* get_one_status() revalidates the resource */
 
     /* prime iterators, and set "filter" mode mark:
      * only dump this connection. */
     cb->args[0] = (long)resource;
     /* cb->args[1] = 0; passed in this way. */
     cb->args[2] = (long)resource;
 
 dump:
     return get_one_status(skb, cb);
 }
 
 int drbd_adm_get_timeout_type(struct sk_buff *skb, struct genl_info *info)
 {
     struct drbd_config_context adm_ctx;
     enum drbd_ret_code retcode;
     struct timeout_parms tp;
     int err;
 
     retcode = drbd_adm_prepare(&adm_ctx, skb, info, DRBD_ADM_NEED_MINOR);
     if (!adm_ctx.reply_skb)
         return retcode;
     if (retcode != NO_ERROR)
         goto out;
 
     tp.timeout_type =
         adm_ctx.device->state.pdsk == D_OUTDATED ? UT_PEER_OUTDATED :
         test_bit(USE_DEGR_WFC_T, &adm_ctx.device->flags) ? UT_DEGRADED :
         UT_DEFAULT;
 
     err = timeout_parms_to_priv_skb(adm_ctx.reply_skb, &tp);
     if (err) {
         nlmsg_free(adm_ctx.reply_skb);
         return err;
     }
 out:
     drbd_adm_finish(&adm_ctx, info, retcode);
     return 0;
 }
 
 int drbd_adm_start_ov(struct sk_buff *skb, struct genl_info *info)
 {
     struct drbd_config_context adm_ctx;
     struct drbd_device *device;
     enum drbd_ret_code retcode;
     struct start_ov_parms parms;
 
     retcode = drbd_adm_prepare(&adm_ctx, skb, info, DRBD_ADM_NEED_MINOR);
     if (!adm_ctx.reply_skb)
         return retcode;
     if (retcode != NO_ERROR)
         goto out;
 
     device = adm_ctx.device;
 
     /* resume from last known position, if possible */
     parms.ov_start_sector = device->ov_start_sector;
     parms.ov_stop_sector = ULLONG_MAX;
     if (info->attrs[DRBD_NLA_START_OV_PARMS]) {
         int err = start_ov_parms_from_attrs(&parms, info);
         if (err) {
             retcode = ERR_MANDATORY_TAG;
             drbd_msg_put_info(adm_ctx.reply_skb, from_attrs_err_to_txt(err));
             goto out;
         }
     }
     mutex_lock(&adm_ctx.resource->adm_mutex);
 
     /* w_make_ov_request expects position to be aligned */
     device->ov_start_sector = parms.ov_start_sector & ~(BM_SECT_PER_BIT-1);
     device->ov_stop_sector = parms.ov_stop_sector;
 
     /* If there is still bitmap IO pending, e.g. previous resync or verify
      * just being finished, wait for it before requesting a new resync. */
     drbd_suspend_io(device);
     wait_event(device->misc_wait, !test_bit(BITMAP_IO, &device->flags));
     retcode = drbd_request_state(device, NS(conn, C_VERIFY_S));
     drbd_resume_io(device);
 
     mutex_unlock(&adm_ctx.resource->adm_mutex);
 out:
     drbd_adm_finish(&adm_ctx, info, retcode);
     return 0;
 }
 
 
 int drbd_adm_new_c_uuid(struct sk_buff *skb, struct genl_info *info)
 {
     struct drbd_config_context adm_ctx;
     struct drbd_device *device;
     enum drbd_ret_code retcode;
     int skip_initial_sync = 0;
     int err;
     struct new_c_uuid_parms args;
 
     retcode = drbd_adm_prepare(&adm_ctx, skb, info, DRBD_ADM_NEED_MINOR);
     if (!adm_ctx.reply_skb)
         return retcode;
     if (retcode != NO_ERROR)
         goto out_nolock;
 
     device = adm_ctx.device;
     memset(&args, 0, sizeof(args));
     if (info->attrs[DRBD_NLA_NEW_C_UUID_PARMS]) {
         err = new_c_uuid_parms_from_attrs(&args, info);
         if (err) {
             retcode = ERR_MANDATORY_TAG;
             drbd_msg_put_info(adm_ctx.reply_skb, from_attrs_err_to_txt(err));
             goto out_nolock;
         }
     }
 
     mutex_lock(&adm_ctx.resource->adm_mutex);
     mutex_lock(device->state_mutex); /* Protects us against serialized state changes. */
 
     if (!get_ldev(device)) {
         retcode = ERR_NO_DISK;
         goto out;
     }
 
     /* this is "skip initial sync", assume to be clean */
     if (device->state.conn == C_CONNECTED &&
         first_peer_device(device)->connection->agreed_pro_version >= 90 &&
         device->ldev->md.uuid[UI_CURRENT] == UUID_JUST_CREATED && args.clear_bm) {
         drbd_info(device, "Preparing to skip initial sync\n");
         skip_initial_sync = 1;
     } else if (device->state.conn != C_STANDALONE) {
         retcode = ERR_CONNECTED;
         goto out_dec;
     }
 
     drbd_uuid_set(device, UI_BITMAP, 0); /* Rotate UI_BITMAP to History 1, etc... */
     drbd_uuid_new_current(device); /* New current, previous to UI_BITMAP */
 
     if (args.clear_bm) {
         err = drbd_bitmap_io(device, &drbd_bmio_clear_n_write,
             "clear_n_write from new_c_uuid", BM_LOCKED_MASK);
         if (err) {
             drbd_err(device, "Writing bitmap failed with %d\n", err);
             retcode = ERR_IO_MD_DISK;
         }
         if (skip_initial_sync) {
             drbd_send_uuids_skip_initial_sync(first_peer_device(device));
             _drbd_uuid_set(device, UI_BITMAP, 0);
             drbd_print_uuids(device, "cleared bitmap UUID");
             spin_lock_irq(&device->resource->req_lock);
             _drbd_set_state(_NS2(device, disk, D_UP_TO_DATE, pdsk, D_UP_TO_DATE),
                     CS_VERBOSE, NULL);
             spin_unlock_irq(&device->resource->req_lock);
         }
     }
 
     drbd_md_sync(device);
 out_dec:
     put_ldev(device);
 out:
     mutex_unlock(device->state_mutex);
     mutex_unlock(&adm_ctx.resource->adm_mutex);
 out_nolock:
     drbd_adm_finish(&adm_ctx, info, retcode);
     return 0;
 }
 
 static enum drbd_ret_code
 drbd_check_resource_name(struct drbd_config_context *adm_ctx)
 {
     const char *name = adm_ctx->resource_name;
     if (!name || !name[0]) {
         drbd_msg_put_info(adm_ctx->reply_skb, "resource name missing");
         return ERR_MANDATORY_TAG;
     }
     /* if we want to use these in sysfs/configfs/debugfs some day,
      * we must not allow slashes */
     if (strchr(name, '/')) {
         drbd_msg_put_info(adm_ctx->reply_skb, "invalid resource name");
         return ERR_INVALID_REQUEST;
     }
     return NO_ERROR;
 }
 
 static void resource_to_info(struct resource_info *info,
                  struct drbd_resource *resource)
 {
     info->res_role = conn_highest_role(first_connection(resource));
     info->res_susp = resource->susp;
     info->res_susp_nod = resource->susp_nod;
     info->res_susp_fen = resource->susp_fen;
 }
 
 int drbd_adm_new_resource(struct sk_buff *skb, struct genl_info *info)
 {
     struct drbd_connection *connection;
     struct drbd_config_context adm_ctx;
     enum drbd_ret_code retcode;
     struct res_opts res_opts;
     int err;
 
     retcode = drbd_adm_prepare(&adm_ctx, skb, info, 0);
     if (!adm_ctx.reply_skb)
         return retcode;
     if (retcode != NO_ERROR)
         goto out;
 
     set_res_opts_defaults(&res_opts);
     err = res_opts_from_attrs(&res_opts, info);
     if (err && err != -ENOMSG) {
         retcode = ERR_MANDATORY_TAG;
         drbd_msg_put_info(adm_ctx.reply_skb, from_attrs_err_to_txt(err));
         goto out;
     }
 
     retcode = drbd_check_resource_name(&adm_ctx);
     if (retcode != NO_ERROR)
         goto out;
 
     if (adm_ctx.resource) {
         if (info->nlhdr->nlmsg_flags & NLM_F_EXCL) {
             retcode = ERR_INVALID_REQUEST;
             drbd_msg_put_info(adm_ctx.reply_skb, "resource exists");
         }
         /* else: still NO_ERROR */
         goto out;
     }
 
     /* not yet safe for genl_family.parallel_ops */
     mutex_lock(&resources_mutex);
     connection = conn_create(adm_ctx.resource_name, &res_opts);
     mutex_unlock(&resources_mutex);
 
     if (connection) {
         struct resource_info resource_info;
 
         mutex_lock(&notification_mutex);
         resource_to_info(&resource_info, connection->resource);
         notify_resource_state(NULL, 0, connection->resource,
                       &resource_info, NOTIFY_CREATE);
         mutex_unlock(&notification_mutex);
     } else
         retcode = ERR_NOMEM;
 
 out:
     drbd_adm_finish(&adm_ctx, info, retcode);
     return 0;
 }
 
 static void device_to_info(struct device_info *info,
                struct drbd_device *device)
 {
     info->dev_disk_state = device->state.disk;
 }
 
 
 int drbd_adm_new_minor(struct sk_buff *skb, struct genl_info *info)
 {
     struct drbd_config_context adm_ctx;
     struct drbd_genlmsghdr *dh = info->userhdr;
     enum drbd_ret_code retcode;
 
     retcode = drbd_adm_prepare(&adm_ctx, skb, info, DRBD_ADM_NEED_RESOURCE);
     if (!adm_ctx.reply_skb)
         return retcode;
     if (retcode != NO_ERROR)
         goto out;
 
     if (dh->minor > MINORMASK) {
         drbd_msg_put_info(adm_ctx.reply_skb, "requested minor out of range");
         retcode = ERR_INVALID_REQUEST;
         goto out;
     }
     if (adm_ctx.volume > DRBD_VOLUME_MAX) {
         drbd_msg_put_info(adm_ctx.reply_skb, "requested volume id out of range");
         retcode = ERR_INVALID_REQUEST;
         goto out;
     }
 
     /* drbd_adm_prepare made sure already
      * that first_peer_device(device)->connection and device->vnr match the request. */
     if (adm_ctx.device) {
         if (info->nlhdr->nlmsg_flags & NLM_F_EXCL)
             retcode = ERR_MINOR_OR_VOLUME_EXISTS;
         /* else: still NO_ERROR */
         goto out;
     }
 
     mutex_lock(&adm_ctx.resource->adm_mutex);
     retcode = drbd_create_device(&adm_ctx, dh->minor);
     if (retcode == NO_ERROR) {
         struct drbd_device *device;
         struct drbd_peer_device *peer_device;
         struct device_info info;
         unsigned int peer_devices = 0;
         enum drbd_notification_type flags;
 
         device = minor_to_device(dh->minor);
         for_each_peer_device(peer_device, device) {
             if (!has_net_conf(peer_device->connection))
                 continue;
             peer_devices++;
         }
 
         device_to_info(&info, device);
         mutex_lock(&notification_mutex);
         flags = (peer_devices--) ? NOTIFY_CONTINUES : 0;
         notify_device_state(NULL, 0, device, &info, NOTIFY_CREATE | flags);
         for_each_peer_device(peer_device, device) {
             struct peer_device_info peer_device_info;
 
             if (!has_net_conf(peer_device->connection))
                 continue;
             peer_device_to_info(&peer_device_info, peer_device);
             flags = (peer_devices--) ? NOTIFY_CONTINUES : 0;
             notify_peer_device_state(NULL, 0, peer_device, &peer_device_info,
                          NOTIFY_CREATE | flags);
         }
         mutex_unlock(&notification_mutex);
     }
     mutex_unlock(&adm_ctx.resource->adm_mutex);
 out:
     drbd_adm_finish(&adm_ctx, info, retcode);
     return 0;
 }
 
 static enum drbd_ret_code adm_del_minor(struct drbd_device *device)
 {
     struct drbd_peer_device *peer_device;
 
     if (device->state.disk == D_DISKLESS &&
         /* no need to be device->state.conn == C_STANDALONE &&
          * we may want to delete a minor from a live replication group.
          */
         device->state.role == R_SECONDARY) {
         struct drbd_connection *connection =
             first_connection(device->resource);
 
         _drbd_request_state(device, NS(conn, C_WF_REPORT_PARAMS),
                     CS_VERBOSE + CS_WAIT_COMPLETE);
 
         /* If the state engine hasn't stopped the sender thread yet, we
          * need to flush the sender work queue before generating the
          * DESTROY events here. */
         if (get_t_state(&connection->worker) == RUNNING)
             drbd_flush_workqueue(&connection->sender_work);
 
         mutex_lock(&notification_mutex);
         for_each_peer_device(peer_device, device) {
             if (!has_net_conf(peer_device->connection))
                 continue;
             notify_peer_device_state(NULL, 0, peer_device, NULL,
                          NOTIFY_DESTROY | NOTIFY_CONTINUES);
         }
         notify_device_state(NULL, 0, device, NULL, NOTIFY_DESTROY);
         mutex_unlock(&notification_mutex);
 
         drbd_delete_device(device);
         return NO_ERROR;
     } else
         return ERR_MINOR_CONFIGURED;
 }
 
 int drbd_adm_del_minor(struct sk_buff *skb, struct genl_info *info)
 {
     struct drbd_config_context adm_ctx;
     enum drbd_ret_code retcode;
 
     retcode = drbd_adm_prepare(&adm_ctx, skb, info, DRBD_ADM_NEED_MINOR);
     if (!adm_ctx.reply_skb)
         return retcode;
     if (retcode != NO_ERROR)
         goto out;
 
     mutex_lock(&adm_ctx.resource->adm_mutex);
     retcode = adm_del_minor(adm_ctx.device);
     mutex_unlock(&adm_ctx.resource->adm_mutex);
 out:
     drbd_adm_finish(&adm_ctx, info, retcode);
     return 0;
 }
 
 static int adm_del_resource(struct drbd_resource *resource)
 {
     struct drbd_connection *connection;
 
     for_each_connection(connection, resource) {
         if (connection->cstate > C_STANDALONE)
             return ERR_NET_CONFIGURED;
     }
     if (!idr_is_empty(&resource->devices))
         return ERR_RES_IN_USE;
 
     /* The state engine has stopped the sender thread, so we don't
      * need to flush the sender work queue before generating the
      * DESTROY event here. */
     mutex_lock(&notification_mutex);
     notify_resource_state(NULL, 0, resource, NULL, NOTIFY_DESTROY);
     mutex_unlock(&notification_mutex);
 
     mutex_lock(&resources_mutex);
     list_del_rcu(&resource->resources);
     mutex_unlock(&resources_mutex);
     /* Make sure all threads have actually stopped: state handling only
      * does drbd_thread_stop_nowait(). */
     list_for_each_entry(connection, &resource->connections, connections)
         drbd_thread_stop(&connection->worker);
     synchronize_rcu();
     drbd_free_resource(resource);
     return NO_ERROR;
 }
 
 int drbd_adm_down(struct sk_buff *skb, struct genl_info *info)
 {
     struct drbd_config_context adm_ctx;
     struct drbd_resource *resource;
     struct drbd_connection *connection;
     struct drbd_device *device;
     int retcode; /* enum drbd_ret_code rsp. enum drbd_state_rv */
     unsigned i;
 
     retcode = drbd_adm_prepare(&adm_ctx, skb, info, DRBD_ADM_NEED_RESOURCE);
     if (!adm_ctx.reply_skb)
         return retcode;
     if (retcode != NO_ERROR)
         goto finish;
 
     resource = adm_ctx.resource;
     mutex_lock(&resource->adm_mutex);
     /* demote */
     for_each_connection(connection, resource) {
         struct drbd_peer_device *peer_device;
 
         idr_for_each_entry(&connection->peer_devices, peer_device, i) {
             retcode = drbd_set_role(peer_device->device, R_SECONDARY, 0);
             if (retcode < SS_SUCCESS) {
                 drbd_msg_put_info(adm_ctx.reply_skb, "failed to demote");
                 goto out;
             }
         }
 
         retcode = conn_try_disconnect(connection, 0);
         if (retcode < SS_SUCCESS) {
             drbd_msg_put_info(adm_ctx.reply_skb, "failed to disconnect");
             goto out;
         }
     }
 
     /* detach */
     idr_for_each_entry(&resource->devices, device, i) {
         retcode = adm_detach(device, 0);
         if (retcode < SS_SUCCESS || retcode > NO_ERROR) {
             drbd_msg_put_info(adm_ctx.reply_skb, "failed to detach");
             goto out;
         }
     }
 
     /* delete volumes */
     idr_for_each_entry(&resource->devices, device, i) {
         retcode = adm_del_minor(device);
         if (retcode != NO_ERROR) {
             /* "can not happen" */
             drbd_msg_put_info(adm_ctx.reply_skb, "failed to delete volume");
             goto out;
         }
     }
 
     retcode = adm_del_resource(resource);
 out:
     mutex_unlock(&resource->adm_mutex);
 finish:
     drbd_adm_finish(&adm_ctx, info, retcode);
     return 0;
 }
 
 int drbd_adm_del_resource(struct sk_buff *skb, struct genl_info *info)
 {
     struct drbd_config_context adm_ctx;
     struct drbd_resource *resource;
     enum drbd_ret_code retcode;
 
     retcode = drbd_adm_prepare(&adm_ctx, skb, info, DRBD_ADM_NEED_RESOURCE);
     if (!adm_ctx.reply_skb)
         return retcode;
     if (retcode != NO_ERROR)
         goto finish;
     resource = adm_ctx.resource;
 
     mutex_lock(&resource->adm_mutex);
     retcode = adm_del_resource(resource);
     mutex_unlock(&resource->adm_mutex);
 finish:
     drbd_adm_finish(&adm_ctx, info, retcode);
     return 0;
 }
 
 void drbd_bcast_event(struct drbd_device *device, const struct sib_info *sib)
 {
     struct sk_buff *msg;
     struct drbd_genlmsghdr *d_out;
     unsigned seq;
     int err = -ENOMEM;
 
     seq = atomic_inc_return(&drbd_genl_seq);
     msg = genlmsg_new(NLMSG_GOODSIZE, GFP_NOIO);
     if (!msg)
         goto failed;
 
     err = -EMSGSIZE;
     d_out = genlmsg_put(msg, 0, seq, &drbd_genl_family, 0, DRBD_EVENT);
     if (!d_out) /* cannot happen, but anyways. */
         goto nla_put_failure;
     d_out->minor = device_to_minor(device);
     d_out->ret_code = NO_ERROR;
 
     if (nla_put_status_info(msg, device, sib))
         goto nla_put_failure;
     genlmsg_end(msg, d_out);
     err = drbd_genl_multicast_events(msg, GFP_NOWAIT);
     /* msg has been consumed or freed in netlink_broadcast() */
     if (err && err != -ESRCH)
         goto failed;
 
     return;
 
 nla_put_failure:
     nlmsg_free(msg);
 failed:
     drbd_err(device, "Error %d while broadcasting event. "
             "Event seq:%u sib_reason:%u\n",
             err, seq, sib->sib_reason);
 }
 
 static int nla_put_notification_header(struct sk_buff *msg,
                        enum drbd_notification_type type)
 {
     struct drbd_notification_header nh = {
         .nh_type = type,
     };
 
     return drbd_notification_header_to_skb(msg, &nh, true);
 }
 
 int notify_resource_state(struct sk_buff *skb,
                unsigned int seq,
                struct drbd_resource *resource,
                struct resource_info *resource_info,
                enum drbd_notification_type type)
 {
     struct resource_statistics resource_statistics;
     struct drbd_genlmsghdr *dh;
     bool multicast = false;
     int err;
 
     if (!skb) {
         seq = atomic_inc_return(&notify_genl_seq);
         skb = genlmsg_new(NLMSG_GOODSIZE, GFP_NOIO);
         err = -ENOMEM;
         if (!skb)
             goto failed;
         multicast = true;
     }
 
     err = -EMSGSIZE;
     dh = genlmsg_put(skb, 0, seq, &drbd_genl_family, 0, DRBD_RESOURCE_STATE);
     if (!dh)
         goto nla_put_failure;
     dh->minor = -1U;
     dh->ret_code = NO_ERROR;
     if (nla_put_drbd_cfg_context(skb, resource, NULL, NULL) ||
         nla_put_notification_header(skb, type) ||
         ((type & ~NOTIFY_FLAGS) != NOTIFY_DESTROY &&
          resource_info_to_skb(skb, resource_info, true)))
         goto nla_put_failure;
     resource_statistics.res_stat_write_ordering = resource->write_ordering;
     err = resource_statistics_to_skb(skb, &resource_statistics, !capable(CAP_SYS_ADMIN));
     if (err)
         goto nla_put_failure;
     genlmsg_end(skb, dh);
     if (multicast) {
         err = drbd_genl_multicast_events(skb, GFP_NOWAIT);
         /* skb has been consumed or freed in netlink_broadcast() */
         if (err && err != -ESRCH)
             goto failed;
     }
     return 0;
 
 nla_put_failure:
     nlmsg_free(skb);
 failed:
     drbd_err(resource, "Error %d while broadcasting event. Event seq:%u\n",
             err, seq);
     return err;
 }
 
 int notify_device_state(struct sk_buff *skb,
              unsigned int seq,
              struct drbd_device *device,
              struct device_info *device_info,
              enum drbd_notification_type type)
 {
     struct device_statistics device_statistics;
     struct drbd_genlmsghdr *dh;
     bool multicast = false;
     int err;
 
     if (!skb) {
         seq = atomic_inc_return(&notify_genl_seq);
         skb = genlmsg_new(NLMSG_GOODSIZE, GFP_NOIO);
         err = -ENOMEM;
         if (!skb)
             goto failed;
         multicast = true;
     }
 
     err = -EMSGSIZE;
     dh = genlmsg_put(skb, 0, seq, &drbd_genl_family, 0, DRBD_DEVICE_STATE);
     if (!dh)
         goto nla_put_failure;
     dh->minor = device->minor;
     dh->ret_code = NO_ERROR;
     if (nla_put_drbd_cfg_context(skb, device->resource, NULL, device) ||
         nla_put_notification_header(skb, type) ||
         ((type & ~NOTIFY_FLAGS) != NOTIFY_DESTROY &&
          device_info_to_skb(skb, device_info, true)))
         goto nla_put_failure;
     device_to_statistics(&device_statistics, device);
     device_statistics_to_skb(skb, &device_statistics, !capable(CAP_SYS_ADMIN));
     genlmsg_end(skb, dh);
     if (multicast) {
         err = drbd_genl_multicast_events(skb, GFP_NOWAIT);
         /* skb has been consumed or freed in netlink_broadcast() */
         if (err && err != -ESRCH)
             goto failed;
     }
     return 0;
 
 nla_put_failure:
     nlmsg_free(skb);
 failed:
     drbd_err(device, "Error %d while broadcasting event. Event seq:%u\n",
          err, seq);
     return err;
 }
 
 int notify_connection_state(struct sk_buff *skb,
                  unsigned int seq,
                  struct drbd_connection *connection,
                  struct connection_info *connection_info,
                  enum drbd_notification_type type)
 {
     struct connection_statistics connection_statistics;
     struct drbd_genlmsghdr *dh;
     bool multicast = false;
     int err;
 
     if (!skb) {
         seq = atomic_inc_return(&notify_genl_seq);
         skb = genlmsg_new(NLMSG_GOODSIZE, GFP_NOIO);
         err = -ENOMEM;
         if (!skb)
             goto failed;
         multicast = true;
     }
 
     err = -EMSGSIZE;
     dh = genlmsg_put(skb, 0, seq, &drbd_genl_family, 0, DRBD_CONNECTION_STATE);
     if (!dh)
         goto nla_put_failure;
     dh->minor = -1U;
     dh->ret_code = NO_ERROR;
     if (nla_put_drbd_cfg_context(skb, connection->resource, connection, NULL) ||
         nla_put_notification_header(skb, type) ||
         ((type & ~NOTIFY_FLAGS) != NOTIFY_DESTROY &&
          connection_info_to_skb(skb, connection_info, true)))
         goto nla_put_failure;
     connection_statistics.conn_congested = test_bit(NET_CONGESTED, &connection->flags);
     connection_statistics_to_skb(skb, &connection_statistics, !capable(CAP_SYS_ADMIN));
     genlmsg_end(skb, dh);
     if (multicast) {
         err = drbd_genl_multicast_events(skb, GFP_NOWAIT);
         /* skb has been consumed or freed in netlink_broadcast() */
         if (err && err != -ESRCH)
             goto failed;
     }
     return 0;
 
 nla_put_failure:
     nlmsg_free(skb);
 failed:
     drbd_err(connection, "Error %d while broadcasting event. Event seq:%u\n",
          err, seq);
     return err;
 }
 
 int notify_peer_device_state(struct sk_buff *skb,
                   unsigned int seq,
                   struct drbd_peer_device *peer_device,
                   struct peer_device_info *peer_device_info,
                   enum drbd_notification_type type)
 {
     struct peer_device_statistics peer_device_statistics;
     struct drbd_resource *resource = peer_device->device->resource;
     struct drbd_genlmsghdr *dh;
     bool multicast = false;
     int err;
 
     if (!skb) {
         seq = atomic_inc_return(&notify_genl_seq);
         skb = genlmsg_new(NLMSG_GOODSIZE, GFP_NOIO);
         err = -ENOMEM;
         if (!skb)
             goto failed;
         multicast = true;
     }
 
     err = -EMSGSIZE;
     dh = genlmsg_put(skb, 0, seq, &drbd_genl_family, 0, DRBD_PEER_DEVICE_STATE);
     if (!dh)
         goto nla_put_failure;
     dh->minor = -1U;
     dh->ret_code = NO_ERROR;
     if (nla_put_drbd_cfg_context(skb, resource, peer_device->connection, peer_device->device) ||
         nla_put_notification_header(skb, type) ||
         ((type & ~NOTIFY_FLAGS) != NOTIFY_DESTROY &&
          peer_device_info_to_skb(skb, peer_device_info, true)))
         goto nla_put_failure;
     peer_device_to_statistics(&peer_device_statistics, peer_device);
     peer_device_statistics_to_skb(skb, &peer_device_statistics, !capable(CAP_SYS_ADMIN));
     genlmsg_end(skb, dh);
     if (multicast) {
         err = drbd_genl_multicast_events(skb, GFP_NOWAIT);
         /* skb has been consumed or freed in netlink_broadcast() */
         if (err && err != -ESRCH)
             goto failed;
     }
     return 0;
 
 nla_put_failure:
     nlmsg_free(skb);
 failed:
     drbd_err(peer_device, "Error %d while broadcasting event. Event seq:%u\n",
          err, seq);
     return err;
 }
 
 void notify_helper(enum drbd_notification_type type,
            struct drbd_device *device, struct drbd_connection *connection,
            const char *name, int status)
 {
     struct drbd_resource *resource = device ? device->resource : connection->resource;
     struct drbd_helper_info helper_info;
     unsigned int seq = atomic_inc_return(&notify_genl_seq);
     struct sk_buff *skb = NULL;
     struct drbd_genlmsghdr *dh;
     int err;
 
     strlcpy(helper_info.helper_name, name, sizeof(helper_info.helper_name));
     helper_info.helper_name_len = min(strlen(name), sizeof(helper_info.helper_name));
     helper_info.helper_status = status;
 
     skb = genlmsg_new(NLMSG_GOODSIZE, GFP_NOIO);
     err = -ENOMEM;
     if (!skb)
         goto fail;
 
     err = -EMSGSIZE;
     dh = genlmsg_put(skb, 0, seq, &drbd_genl_family, 0, DRBD_HELPER);
     if (!dh)
         goto fail;
     dh->minor = device ? device->minor : -1;
     dh->ret_code = NO_ERROR;
     mutex_lock(&notification_mutex);
     if (nla_put_drbd_cfg_context(skb, resource, connection, device) ||
         nla_put_notification_header(skb, type) ||
         drbd_helper_info_to_skb(skb, &helper_info, true))
         goto unlock_fail;
     genlmsg_end(skb, dh);
     err = drbd_genl_multicast_events(skb, GFP_NOWAIT);
     skb = NULL;
     /* skb has been consumed or freed in netlink_broadcast() */
     if (err && err != -ESRCH)
         goto unlock_fail;
     mutex_unlock(&notification_mutex);
     return;
 
 unlock_fail:
     mutex_unlock(&notification_mutex);
 fail:
     nlmsg_free(skb);
     drbd_err(resource, "Error %d while broadcasting event. Event seq:%u\n",
          err, seq);
 }
 
 static int notify_initial_state_done(struct sk_buff *skb, unsigned int seq)
 {
     struct drbd_genlmsghdr *dh;
     int err;
 
     err = -EMSGSIZE;
     dh = genlmsg_put(skb, 0, seq, &drbd_genl_family, 0, DRBD_INITIAL_STATE_DONE);
     if (!dh)
         goto nla_put_failure;
     dh->minor = -1U;
     dh->ret_code = NO_ERROR;
     if (nla_put_notification_header(skb, NOTIFY_EXISTS))
         goto nla_put_failure;
     genlmsg_end(skb, dh);
     return 0;
 
 nla_put_failure:
     nlmsg_free(skb);
     pr_err("Error %d sending event. Event seq:%u\n", err, seq);
     return err;
 }
 
 static void free_state_changes(struct list_head *list)
 {
     while (!list_empty(list)) {
         struct drbd_state_change *state_change =
             list_first_entry(list, struct drbd_state_change, list);
         list_del(&state_change->list);
         forget_state_change(state_change);
     }
 }
 
 static unsigned int notifications_for_state_change(struct drbd_state_change *state_change)
 {
     return 1 +
            state_change->n_connections +
            state_change->n_devices +
            state_change->n_devices * state_change->n_connections;
 }
 
 static int get_initial_state(struct sk_buff *skb, struct netlink_callback *cb)
 {
     struct drbd_state_change *state_change = (struct drbd_state_change *)cb->args[0];
     unsigned int seq = cb->args[2];
     unsigned int n;
     enum drbd_notification_type flags = 0;
     int err = 0;
 
     /* There is no need for taking notification_mutex here: it doesn't
        matter if the initial state events mix with later state chage
        events; we can always tell the events apart by the NOTIFY_EXISTS
        flag. */
 
     cb->args[5]--;
     if (cb->args[5] == 1) {
         err = notify_initial_state_done(skb, seq);
         goto out;
     }
     n = cb->args[4]++;
     if (cb->args[4] < cb->args[3])
         flags |= NOTIFY_CONTINUES;
     if (n < 1) {
         err = notify_resource_state_change(skb, seq, state_change->resource,
                          NOTIFY_EXISTS | flags);
         goto next;
     }
     n--;
     if (n < state_change->n_connections) {
         err = notify_connection_state_change(skb, seq, &state_change->connections[n],
                            NOTIFY_EXISTS | flags);
         goto next;
     }
     n -= state_change->n_connections;
     if (n < state_change->n_devices) {
         err = notify_device_state_change(skb, seq, &state_change->devices[n],
                        NOTIFY_EXISTS | flags);
         goto next;
     }
     n -= state_change->n_devices;
     if (n < state_change->n_devices * state_change->n_connections) {
         err = notify_peer_device_state_change(skb, seq, &state_change->peer_devices[n],
                         NOTIFY_EXISTS | flags);
         goto next;
     }
 
 next:
     if (cb->args[4] == cb->args[3]) {
         struct drbd_state_change *next_state_change =
             list_entry(state_change->list.next,
                    struct drbd_state_change, list);
         cb->args[0] = (long)next_state_change;
         cb->args[3] = notifications_for_state_change(next_state_change);
         cb->args[4] = 0;
     }
 out:
     if (err)
         return err;
     else
         return skb->len;
 }
 
 int drbd_adm_get_initial_state(struct sk_buff *skb, struct netlink_callback *cb)
 {
     struct drbd_resource *resource;
     LIST_HEAD(head);
 
     if (cb->args[5] >= 1) {
         if (cb->args[5] > 1)
             return get_initial_state(skb, cb);
         if (cb->args[0]) {
             struct drbd_state_change *state_change =
                 (struct drbd_state_change *)cb->args[0];
 
             /* connect list to head */
             list_add(&head, &state_change->list);
             free_state_changes(&head);
         }
         return 0;
     }
 
     cb->args[5] = 2;  /* number of iterations */
     mutex_lock(&resources_mutex);
     for_each_resource(resource, &drbd_resources) {
         struct drbd_state_change *state_change;
 
         state_change = remember_old_state(resource, GFP_KERNEL);
         if (!state_change) {
             if (!list_empty(&head))
                 free_state_changes(&head);
             mutex_unlock(&resources_mutex);
             return -ENOMEM;
         }
         copy_old_to_new_state_change(state_change);
         list_add_tail(&state_change->list, &head);
         cb->args[5] += notifications_for_state_change(state_change);
     }
     mutex_unlock(&resources_mutex);
 
     if (!list_empty(&head)) {
         struct drbd_state_change *state_change =
             list_entry(head.next, struct drbd_state_change, list);
         cb->args[0] = (long)state_change;
         cb->args[3] = notifications_for_state_change(state_change);
         list_del(&head);  /* detach list from head */
     }
 
     cb->args[2] = cb->nlh->nlmsg_seq;
     return get_initial_state(skb, cb);
 }