dlmrecovery.c

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/* -*- mode: c; c-basic-offset: 8; -*-
 * vim: noexpandtab sw=8 ts=8 sts=0:
 *
 * dlmrecovery.c
 *
 * recovery stuff
 *
 * Copyright (C) 2004 Oracle.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 *
 */


#include <linux/module.h>
#include <linux/fs.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/highmem.h>
#include <linux/init.h>
#include <linux/sysctl.h>
#include <linux/random.h>
#include <linux/blkdev.h>
#include <linux/socket.h>
#include <linux/inet.h>
#include <linux/timer.h>
#include <linux/kthread.h>
#include <linux/delay.h>


#include "cluster/heartbeat.h"
#include "cluster/nodemanager.h"
#include "cluster/tcp.h"

#include "dlmapi.h"
#include "dlmcommon.h"
#include "dlmdomain.h"

#define MLOG_MASK_PREFIX (ML_DLM|ML_DLM_RECOVERY)
#include "cluster/masklog.h"

static void dlm_do_local_recovery_cleanup(struct dlm_ctxt *dlm, u8 dead_node);

static int dlm_recovery_thread(void *data);
void dlm_complete_recovery_thread(struct dlm_ctxt *dlm);
int dlm_launch_recovery_thread(struct dlm_ctxt *dlm);
void dlm_kick_recovery_thread(struct dlm_ctxt *dlm);
static int dlm_do_recovery(struct dlm_ctxt *dlm);

static int dlm_pick_recovery_master(struct dlm_ctxt *dlm);
static int dlm_remaster_locks(struct dlm_ctxt *dlm, u8 dead_node);
static int dlm_init_recovery_area(struct dlm_ctxt *dlm, u8 dead_node);
static int dlm_request_all_locks(struct dlm_ctxt *dlm,
                 u8 request_from, u8 dead_node);
static void dlm_destroy_recovery_area(struct dlm_ctxt *dlm, u8 dead_node);

static inline int dlm_num_locks_in_lockres(struct dlm_lock_resource *res);
static void dlm_init_migratable_lockres(struct dlm_migratable_lockres *mres,
                    const char *lockname, int namelen,
                    int total_locks, u64 cookie,
                    u8 flags, u8 master);
static int dlm_send_mig_lockres_msg(struct dlm_ctxt *dlm,
                    struct dlm_migratable_lockres *mres,
                    u8 send_to,
                    struct dlm_lock_resource *res,
                    int total_locks);
static int dlm_process_recovery_data(struct dlm_ctxt *dlm,
                     struct dlm_lock_resource *res,
                     struct dlm_migratable_lockres *mres);
static int dlm_send_finalize_reco_message(struct dlm_ctxt *dlm);
static int dlm_send_all_done_msg(struct dlm_ctxt *dlm,
                 u8 dead_node, u8 send_to);
static int dlm_send_begin_reco_message(struct dlm_ctxt *dlm, u8 dead_node);
static void dlm_move_reco_locks_to_list(struct dlm_ctxt *dlm,
                    struct list_head *list, u8 dead_node);
static void dlm_finish_local_lockres_recovery(struct dlm_ctxt *dlm,
                          u8 dead_node, u8 new_master);
static void dlm_reco_ast(void *astdata);
static void dlm_reco_bast(void *astdata, int blocked_type);
static void dlm_reco_unlock_ast(void *astdata, enum dlm_status st);
static void dlm_request_all_locks_worker(struct dlm_work_item *item,
                     void *data);
static void dlm_mig_lockres_worker(struct dlm_work_item *item, void *data);
static int dlm_lockres_master_requery(struct dlm_ctxt *dlm,
                      struct dlm_lock_resource *res,
                      u8 *real_master);

static u64 dlm_get_next_mig_cookie(void);

static DEFINE_SPINLOCK(dlm_reco_state_lock);
static DEFINE_SPINLOCK(dlm_mig_cookie_lock);
static u64 dlm_mig_cookie = 1;

static u64 dlm_get_next_mig_cookie(void)
{
    u64 c;
    spin_lock(&dlm_mig_cookie_lock);
    c = dlm_mig_cookie;
    if (dlm_mig_cookie == (~0ULL))
        dlm_mig_cookie = 1;
    else
        dlm_mig_cookie++;
    spin_unlock(&dlm_mig_cookie_lock);
    return c;
}

static inline void dlm_set_reco_dead_node(struct dlm_ctxt *dlm,
                      u8 dead_node)
{
    assert_spin_locked(&dlm->spinlock);
    if (dlm->reco.dead_node != dead_node)
        mlog(0, "%s: changing dead_node from %u to %u\n",
             dlm->name, dlm->reco.dead_node, dead_node);
    dlm->reco.dead_node = dead_node;
}

static inline void dlm_set_reco_master(struct dlm_ctxt *dlm,
                       u8 master)
{
    assert_spin_locked(&dlm->spinlock);
    mlog(0, "%s: changing new_master from %u to %u\n",
         dlm->name, dlm->reco.new_master, master);
    dlm->reco.new_master = master;
}

static inline void __dlm_reset_recovery(struct dlm_ctxt *dlm)
{
    assert_spin_locked(&dlm->spinlock);
    clear_bit(dlm->reco.dead_node, dlm->recovery_map);
    dlm_set_reco_dead_node(dlm, O2NM_INVALID_NODE_NUM);
    dlm_set_reco_master(dlm, O2NM_INVALID_NODE_NUM);
}

static inline void dlm_reset_recovery(struct dlm_ctxt *dlm)
{
    spin_lock(&dlm->spinlock);
    __dlm_reset_recovery(dlm);
    spin_unlock(&dlm->spinlock);
}

/* Worker function used during recovery. */
void dlm_dispatch_work(struct work_struct *work)
{
    struct dlm_ctxt *dlm =
        container_of(work, struct dlm_ctxt, dispatched_work);
    LIST_HEAD(tmp_list);
    struct dlm_work_item *item, *next;
    dlm_workfunc_t *workfunc;
    int tot=0;

    spin_lock(&dlm->work_lock);
    list_splice_init(&dlm->work_list, &tmp_list);
    spin_unlock(&dlm->work_lock);

    list_for_each_entry(item, &tmp_list, list) {
        tot++;
    }
    mlog(0, "%s: work thread has %d work items\n", dlm->name, tot);

    list_for_each_entry_safe(item, next, &tmp_list, list) {
        workfunc = item->func;
        list_del_init(&item->list);

        /* already have ref on dlm to avoid having
         * it disappear.  just double-check. */
        BUG_ON(item->dlm != dlm);

        /* this is allowed to sleep and
         * call network stuff */
        workfunc(item, item->data);

        dlm_put(dlm);
        kfree(item);
    }
}

/*
 * RECOVERY THREAD
 */

void dlm_kick_recovery_thread(struct dlm_ctxt *dlm)
{
    /* wake the recovery thread
     * this will wake the reco thread in one of three places
     * 1) sleeping with no recovery happening
     * 2) sleeping with recovery mastered elsewhere
     * 3) recovery mastered here, waiting on reco data */

    wake_up(&dlm->dlm_reco_thread_wq);
}

/* Launch the recovery thread */
int dlm_launch_recovery_thread(struct dlm_ctxt *dlm)
{
    mlog(0, "starting dlm recovery thread...\n");

    dlm->dlm_reco_thread_task = kthread_run(dlm_recovery_thread, dlm,
                        "dlm_reco_thread");
    if (IS_ERR(dlm->dlm_reco_thread_task)) {
        mlog_errno(PTR_ERR(dlm->dlm_reco_thread_task));
        dlm->dlm_reco_thread_task = NULL;
        return -EINVAL;
    }

    return 0;
}

void dlm_complete_recovery_thread(struct dlm_ctxt *dlm)
{
    if (dlm->dlm_reco_thread_task) {
        mlog(0, "waiting for dlm recovery thread to exit\n");
        kthread_stop(dlm->dlm_reco_thread_task);
        dlm->dlm_reco_thread_task = NULL;
    }
}



/*
 * this is lame, but here's how recovery works...
 * 1) all recovery threads cluster wide will work on recovering
 *    ONE node at a time
 * 2) negotiate who will take over all the locks for the dead node.
 *    thats right... ALL the locks.
 * 3) once a new master is chosen, everyone scans all locks
 *    and moves aside those mastered by the dead guy
 * 4) each of these locks should be locked until recovery is done
 * 5) the new master collects up all of secondary lock queue info
 *    one lock at a time, forcing each node to communicate back
 *    before continuing
 * 6) each secondary lock queue responds with the full known lock info
 * 7) once the new master has run all its locks, it sends a ALLDONE!
 *    message to everyone
 * 8) upon receiving this message, the secondary queue node unlocks
 *    and responds to the ALLDONE
 * 9) once the new master gets responses from everyone, he unlocks
 *    everything and recovery for this dead node is done
 *10) go back to 2) while there are still dead nodes
 *
 */

static void dlm_print_reco_node_status(struct dlm_ctxt *dlm)
{
    struct dlm_reco_node_data *ndata;
    struct dlm_lock_resource *res;

    mlog(ML_NOTICE, "%s(%d): recovery info, state=%s, dead=%u, master=%u\n",
         dlm->name, task_pid_nr(dlm->dlm_reco_thread_task),
         dlm->reco.state & DLM_RECO_STATE_ACTIVE ? "ACTIVE" : "inactive",
         dlm->reco.dead_node, dlm->reco.new_master);

    list_for_each_entry(ndata, &dlm->reco.node_data, list) {
        char *st = "unknown";
        switch (ndata->state) {
            case DLM_RECO_NODE_DATA_INIT:
                st = "init";
                break;
            case DLM_RECO_NODE_DATA_REQUESTING:
                st = "requesting";
                break;
            case DLM_RECO_NODE_DATA_DEAD:
                st = "dead";
                break;
            case DLM_RECO_NODE_DATA_RECEIVING:
                st = "receiving";
                break;
            case DLM_RECO_NODE_DATA_REQUESTED:
                st = "requested";
                break;
            case DLM_RECO_NODE_DATA_DONE:
                st = "done";
                break;
            case DLM_RECO_NODE_DATA_FINALIZE_SENT:
                st = "finalize-sent";
                break;
            default:
                st = "bad";
                break;
        }
        mlog(ML_NOTICE, "%s: reco state, node %u, state=%s\n",
             dlm->name, ndata->node_num, st);
    }
    list_for_each_entry(res, &dlm->reco.resources, recovering) {
        mlog(ML_NOTICE, "%s: lockres %.*s on recovering list\n",
             dlm->name, res->lockname.len, res->lockname.name);
    }
}

#define DLM_RECO_THREAD_TIMEOUT_MS (5 * 1000)

static int dlm_recovery_thread(void *data)
{
    int status;
    struct dlm_ctxt *dlm = data;
    unsigned long timeout = msecs_to_jiffies(DLM_RECO_THREAD_TIMEOUT_MS);

    mlog(0, "dlm thread running for %s...\n", dlm->name);

    while (!kthread_should_stop()) {
        if (dlm_domain_fully_joined(dlm)) {
            status = dlm_do_recovery(dlm);
            if (status == -EAGAIN) {
                /* do not sleep, recheck immediately. */
                continue;
            }
            if (status < 0)
                mlog_errno(status);
        }

        wait_event_interruptible_timeout(dlm->dlm_reco_thread_wq,
                         kthread_should_stop(),
                         timeout);
    }

    mlog(0, "quitting DLM recovery thread\n");
    return 0;
}

/* returns true when the recovery master has contacted us */
static int dlm_reco_master_ready(struct dlm_ctxt *dlm)
{
    int ready;
    spin_lock(&dlm->spinlock);
    ready = (dlm->reco.new_master != O2NM_INVALID_NODE_NUM);
    spin_unlock(&dlm->spinlock);
    return ready;
}

/* returns true if node is no longer in the domain
 * could be dead or just not joined */
int dlm_is_node_dead(struct dlm_ctxt *dlm, u8 node)
{
    int dead;
    spin_lock(&dlm->spinlock);
    dead = !test_bit(node, dlm->domain_map);
    spin_unlock(&dlm->spinlock);
    return dead;
}

/* returns true if node is no longer in the domain
 * could be dead or just not joined */
static int dlm_is_node_recovered(struct dlm_ctxt *dlm, u8 node)
{
    int recovered;
    spin_lock(&dlm->spinlock);
    recovered = !test_bit(node, dlm->recovery_map);
    spin_unlock(&dlm->spinlock);
    return recovered;
}


void dlm_wait_for_node_death(struct dlm_ctxt *dlm, u8 node, int timeout)
{
    if (dlm_is_node_dead(dlm, node))
        return;

    printk(KERN_NOTICE "o2dlm: Waiting on the death of node %u in "
           "domain %s\n", node, dlm->name);

    if (timeout)
        wait_event_timeout(dlm->dlm_reco_thread_wq,
                   dlm_is_node_dead(dlm, node),
                   msecs_to_jiffies(timeout));
    else
        wait_event(dlm->dlm_reco_thread_wq,
               dlm_is_node_dead(dlm, node));
}

void dlm_wait_for_node_recovery(struct dlm_ctxt *dlm, u8 node, int timeout)
{
    if (dlm_is_node_recovered(dlm, node))
        return;

    printk(KERN_NOTICE "o2dlm: Waiting on the recovery of node %u in "
           "domain %s\n", node, dlm->name);

    if (timeout)
        wait_event_timeout(dlm->dlm_reco_thread_wq,
                   dlm_is_node_recovered(dlm, node),
                   msecs_to_jiffies(timeout));
    else
        wait_event(dlm->dlm_reco_thread_wq,
               dlm_is_node_recovered(dlm, node));
}

/* callers of the top-level api calls (dlmlock/dlmunlock) should
 * block on the dlm->reco.event when recovery is in progress.
 * the dlm recovery thread will set this state when it begins
 * recovering a dead node (as the new master or not) and clear
 * the state and wake as soon as all affected lock resources have
 * been marked with the RECOVERY flag */
static int dlm_in_recovery(struct dlm_ctxt *dlm)
{
    int in_recovery;
    spin_lock(&dlm->spinlock);
    in_recovery = !!(dlm->reco.state & DLM_RECO_STATE_ACTIVE);
    spin_unlock(&dlm->spinlock);
    return in_recovery;
}


void dlm_wait_for_recovery(struct dlm_ctxt *dlm)
{
    if (dlm_in_recovery(dlm)) {
        mlog(0, "%s: reco thread %d in recovery: "
             "state=%d, master=%u, dead=%u\n",
             dlm->name, task_pid_nr(dlm->dlm_reco_thread_task),
             dlm->reco.state, dlm->reco.new_master,
             dlm->reco.dead_node);
    }
    wait_event(dlm->reco.event, !dlm_in_recovery(dlm));
}

static void dlm_begin_recovery(struct dlm_ctxt *dlm)
{
    spin_lock(&dlm->spinlock);
    BUG_ON(dlm->reco.state & DLM_RECO_STATE_ACTIVE);
    printk(KERN_NOTICE "o2dlm: Begin recovery on domain %s for node %u\n",
           dlm->name, dlm->reco.dead_node);
    dlm->reco.state |= DLM_RECO_STATE_ACTIVE;
    spin_unlock(&dlm->spinlock);
}

static void dlm_end_recovery(struct dlm_ctxt *dlm)
{
    spin_lock(&dlm->spinlock);
    BUG_ON(!(dlm->reco.state & DLM_RECO_STATE_ACTIVE));
    dlm->reco.state &= ~DLM_RECO_STATE_ACTIVE;
    spin_unlock(&dlm->spinlock);
    printk(KERN_NOTICE "o2dlm: End recovery on domain %s\n", dlm->name);
    wake_up(&dlm->reco.event);
}

static void dlm_print_recovery_master(struct dlm_ctxt *dlm)
{
    printk(KERN_NOTICE "o2dlm: Node %u (%s) is the Recovery Master for the "
           "dead node %u in domain %s\n", dlm->reco.new_master,
           (dlm->node_num == dlm->reco.new_master ? "me" : "he"),
           dlm->reco.dead_node, dlm->name);
}

static int dlm_do_recovery(struct dlm_ctxt *dlm)
{
    int status = 0;
    int ret;

    spin_lock(&dlm->spinlock);

    /* check to see if the new master has died */
    if (dlm->reco.new_master != O2NM_INVALID_NODE_NUM &&
        test_bit(dlm->reco.new_master, dlm->recovery_map)) {
        mlog(0, "new master %u died while recovering %u!\n",
             dlm->reco.new_master, dlm->reco.dead_node);
        /* unset the new_master, leave dead_node */
        dlm_set_reco_master(dlm, O2NM_INVALID_NODE_NUM);
    }

    /* select a target to recover */
    if (dlm->reco.dead_node == O2NM_INVALID_NODE_NUM) {
        int bit;

        bit = find_next_bit (dlm->recovery_map, O2NM_MAX_NODES, 0);
        if (bit >= O2NM_MAX_NODES || bit < 0)
            dlm_set_reco_dead_node(dlm, O2NM_INVALID_NODE_NUM);
        else
            dlm_set_reco_dead_node(dlm, bit);
    } else if (!test_bit(dlm->reco.dead_node, dlm->recovery_map)) {
        /* BUG? */
        mlog(ML_ERROR, "dead_node %u no longer in recovery map!\n",
             dlm->reco.dead_node);
        dlm_set_reco_dead_node(dlm, O2NM_INVALID_NODE_NUM);
    }

    if (dlm->reco.dead_node == O2NM_INVALID_NODE_NUM) {
        // mlog(0, "nothing to recover!  sleeping now!\n");
        spin_unlock(&dlm->spinlock);
        /* return to main thread loop and sleep. */
        return 0;
    }
    mlog(0, "%s(%d):recovery thread found node %u in the recovery map!\n",
         dlm->name, task_pid_nr(dlm->dlm_reco_thread_task),
         dlm->reco.dead_node);
    spin_unlock(&dlm->spinlock);

    /* take write barrier */
    /* (stops the list reshuffling thread, proxy ast handling) */
    dlm_begin_recovery(dlm);

    if (dlm->reco.new_master == dlm->node_num)
        goto master_here;

    if (dlm->reco.new_master == O2NM_INVALID_NODE_NUM) {
        /* choose a new master, returns 0 if this node
         * is the master, -EEXIST if it's another node.
         * this does not return until a new master is chosen
         * or recovery completes entirely. */
        ret = dlm_pick_recovery_master(dlm);
        if (!ret) {
            /* already notified everyone.  go. */
            goto master_here;
        }
        mlog(0, "another node will master this recovery session.\n");
    }

    dlm_print_recovery_master(dlm);

    /* it is safe to start everything back up here
     * because all of the dead node's lock resources
     * have been marked as in-recovery */
    dlm_end_recovery(dlm);

    /* sleep out in main dlm_recovery_thread loop. */
    return 0;

master_here:
    dlm_print_recovery_master(dlm);

    status = dlm_remaster_locks(dlm, dlm->reco.dead_node);
    if (status < 0) {
        /* we should never hit this anymore */
        mlog(ML_ERROR, "%s: Error %d remastering locks for node %u, "
             "retrying.\n", dlm->name, status, dlm->reco.dead_node);
        /* yield a bit to allow any final network messages
         * to get handled on remaining nodes */
        msleep(100);
    } else {
        /* success!  see if any other nodes need recovery */
        mlog(0, "DONE mastering recovery of %s:%u here(this=%u)!\n",
             dlm->name, dlm->reco.dead_node, dlm->node_num);
        dlm_reset_recovery(dlm);
    }
    dlm_end_recovery(dlm);

    /* continue and look for another dead node */
    return -EAGAIN;
}

static int dlm_remaster_locks(struct dlm_ctxt *dlm, u8 dead_node)
{
    int status = 0;
    struct dlm_reco_node_data *ndata;
    int all_nodes_done;
    int destroy = 0;
    int pass = 0;

    do {
        /* we have become recovery master.  there is no escaping
         * this, so just keep trying until we get it. */
        status = dlm_init_recovery_area(dlm, dead_node);
        if (status < 0) {
            mlog(ML_ERROR, "%s: failed to alloc recovery area, "
                 "retrying\n", dlm->name);
            msleep(1000);
        }
    } while (status != 0);

    /* safe to access the node data list without a lock, since this
     * process is the only one to change the list */
    list_for_each_entry(ndata, &dlm->reco.node_data, list) {
        BUG_ON(ndata->state != DLM_RECO_NODE_DATA_INIT);
        ndata->state = DLM_RECO_NODE_DATA_REQUESTING;

        mlog(0, "%s: Requesting lock info from node %u\n", dlm->name,
             ndata->node_num);

        if (ndata->node_num == dlm->node_num) {
            ndata->state = DLM_RECO_NODE_DATA_DONE;
            continue;
        }

        do {
            status = dlm_request_all_locks(dlm, ndata->node_num,
                               dead_node);
            if (status < 0) {
                mlog_errno(status);
                if (dlm_is_host_down(status)) {
                    /* node died, ignore it for recovery */
                    status = 0;
                    ndata->state = DLM_RECO_NODE_DATA_DEAD;
                    /* wait for the domain map to catch up
                     * with the network state. */
                    wait_event_timeout(dlm->dlm_reco_thread_wq,
                               dlm_is_node_dead(dlm,
                                ndata->node_num),
                               msecs_to_jiffies(1000));
                    mlog(0, "waited 1 sec for %u, "
                         "dead? %s\n", ndata->node_num,
                         dlm_is_node_dead(dlm, ndata->node_num) ?
                         "yes" : "no");
                } else {
                    /* -ENOMEM on the other node */
                    mlog(0, "%s: node %u returned "
                         "%d during recovery, retrying "
                         "after a short wait\n",
                         dlm->name, ndata->node_num,
                         status);
                    msleep(100);
                }
            }
        } while (status != 0);

        spin_lock(&dlm_reco_state_lock);
        switch (ndata->state) {
            case DLM_RECO_NODE_DATA_INIT:
            case DLM_RECO_NODE_DATA_FINALIZE_SENT:
            case DLM_RECO_NODE_DATA_REQUESTED:
                BUG();
                break;
            case DLM_RECO_NODE_DATA_DEAD:
                mlog(0, "node %u died after requesting "
                     "recovery info for node %u\n",
                     ndata->node_num, dead_node);
                /* fine.  don't need this node's info.
                 * continue without it. */
                break;
            case DLM_RECO_NODE_DATA_REQUESTING:
                ndata->state = DLM_RECO_NODE_DATA_REQUESTED;
                mlog(0, "now receiving recovery data from "
                     "node %u for dead node %u\n",
                     ndata->node_num, dead_node);
                break;
            case DLM_RECO_NODE_DATA_RECEIVING:
                mlog(0, "already receiving recovery data from "
                     "node %u for dead node %u\n",
                     ndata->node_num, dead_node);
                break;
            case DLM_RECO_NODE_DATA_DONE:
                mlog(0, "already DONE receiving recovery data "
                     "from node %u for dead node %u\n",
                     ndata->node_num, dead_node);
                break;
        }
        spin_unlock(&dlm_reco_state_lock);
    }

    mlog(0, "%s: Done requesting all lock info\n", dlm->name);

    /* nodes should be sending reco data now
     * just need to wait */

    while (1) {
        /* check all the nodes now to see if we are
         * done, or if anyone died */
        all_nodes_done = 1;
        spin_lock(&dlm_reco_state_lock);
        list_for_each_entry(ndata, &dlm->reco.node_data, list) {
            mlog(0, "checking recovery state of node %u\n",
                 ndata->node_num);
            switch (ndata->state) {
                case DLM_RECO_NODE_DATA_INIT:
                case DLM_RECO_NODE_DATA_REQUESTING:
                    mlog(ML_ERROR, "bad ndata state for "
                         "node %u: state=%d\n",
                         ndata->node_num, ndata->state);
                    BUG();
                    break;
                case DLM_RECO_NODE_DATA_DEAD:
                    mlog(0, "node %u died after "
                         "requesting recovery info for "
                         "node %u\n", ndata->node_num,
                         dead_node);
                    break;
                case DLM_RECO_NODE_DATA_RECEIVING:
                case DLM_RECO_NODE_DATA_REQUESTED:
                    mlog(0, "%s: node %u still in state %s\n",
                         dlm->name, ndata->node_num,
                         ndata->state==DLM_RECO_NODE_DATA_RECEIVING ?
                         "receiving" : "requested");
                    all_nodes_done = 0;
                    break;
                case DLM_RECO_NODE_DATA_DONE:
                    mlog(0, "%s: node %u state is done\n",
                         dlm->name, ndata->node_num);
                    break;
                case DLM_RECO_NODE_DATA_FINALIZE_SENT:
                    mlog(0, "%s: node %u state is finalize\n",
                         dlm->name, ndata->node_num);
                    break;
            }
        }
        spin_unlock(&dlm_reco_state_lock);

        mlog(0, "pass #%d, all_nodes_done?: %s\n", ++pass,
             all_nodes_done?"yes":"no");
        if (all_nodes_done) {
            int ret;

            /* all nodes are now in DLM_RECO_NODE_DATA_DONE state
             * just send a finalize message to everyone and
             * clean up */
            mlog(0, "all nodes are done! send finalize\n");
            ret = dlm_send_finalize_reco_message(dlm);
            if (ret < 0)
                mlog_errno(ret);

            spin_lock(&dlm->spinlock);
            dlm_finish_local_lockres_recovery(dlm, dead_node,
                              dlm->node_num);
            spin_unlock(&dlm->spinlock);
            mlog(0, "should be done with recovery!\n");

            mlog(0, "finishing recovery of %s at %lu, "
                 "dead=%u, this=%u, new=%u\n", dlm->name,
                 jiffies, dlm->reco.dead_node,
                 dlm->node_num, dlm->reco.new_master);
            destroy = 1;
            status = 0;
            /* rescan everything marked dirty along the way */
            dlm_kick_thread(dlm, NULL);
            break;
        }
        /* wait to be signalled, with periodic timeout
         * to check for node death */
        wait_event_interruptible_timeout(dlm->dlm_reco_thread_wq,
                     kthread_should_stop(),
                     msecs_to_jiffies(DLM_RECO_THREAD_TIMEOUT_MS));

    }

    if (destroy)
        dlm_destroy_recovery_area(dlm, dead_node);

    return status;
}

static int dlm_init_recovery_area(struct dlm_ctxt *dlm, u8 dead_node)
{
    int num=0;
    struct dlm_reco_node_data *ndata;

    spin_lock(&dlm->spinlock);
    memcpy(dlm->reco.node_map, dlm->domain_map, sizeof(dlm->domain_map));
    /* nodes can only be removed (by dying) after dropping
     * this lock, and death will be trapped later, so this should do */
    spin_unlock(&dlm->spinlock);

    while (1) {
        num = find_next_bit (dlm->reco.node_map, O2NM_MAX_NODES, num);
        if (num >= O2NM_MAX_NODES) {
            break;
        }
        BUG_ON(num == dead_node);

        ndata = kzalloc(sizeof(*ndata), GFP_NOFS);
        if (!ndata) {
            dlm_destroy_recovery_area(dlm, dead_node);
            return -ENOMEM;
        }
        ndata->node_num = num;
        ndata->state = DLM_RECO_NODE_DATA_INIT;
        spin_lock(&dlm_reco_state_lock);
        list_add_tail(&ndata->list, &dlm->reco.node_data);
        spin_unlock(&dlm_reco_state_lock);
        num++;
    }

    return 0;
}

static void dlm_destroy_recovery_area(struct dlm_ctxt *dlm, u8 dead_node)
{
    struct dlm_reco_node_data *ndata, *next;
    LIST_HEAD(tmplist);

    spin_lock(&dlm_reco_state_lock);
    list_splice_init(&dlm->reco.node_data, &tmplist);
    spin_unlock(&dlm_reco_state_lock);

    list_for_each_entry_safe(ndata, next, &tmplist, list) {
        list_del_init(&ndata->list);
        kfree(ndata);
    }
}

static int dlm_request_all_locks(struct dlm_ctxt *dlm, u8 request_from,
                 u8 dead_node)
{
    struct dlm_lock_request lr;
    enum dlm_status ret;

    mlog(0, "\n");


    mlog(0, "dlm_request_all_locks: dead node is %u, sending request "
          "to %u\n", dead_node, request_from);

    memset(&lr, 0, sizeof(lr));
    lr.node_idx = dlm->node_num;
    lr.dead_node = dead_node;

    // send message
    ret = DLM_NOLOCKMGR;
    ret = o2net_send_message(DLM_LOCK_REQUEST_MSG, dlm->key,
                 &lr, sizeof(lr), request_from, NULL);

    /* negative status is handled by caller */
    if (ret < 0)
        mlog(ML_ERROR, "%s: Error %d send LOCK_REQUEST to node %u "
             "to recover dead node %u\n", dlm->name, ret,
             request_from, dead_node);
    // return from here, then
    // sleep until all received or error
    return ret;

}

int dlm_request_all_locks_handler(struct o2net_msg *msg, u32 len, void *data,
                  void **ret_data)
{
    struct dlm_ctxt *dlm = data;
    struct dlm_lock_request *lr = (struct dlm_lock_request *)msg->buf;
    char *buf = NULL;
    struct dlm_work_item *item = NULL;

    if (!dlm_grab(dlm))
        return -EINVAL;

    if (lr->dead_node != dlm->reco.dead_node) {
        mlog(ML_ERROR, "%s: node %u sent dead_node=%u, but local "
             "dead_node is %u\n", dlm->name, lr->node_idx,
             lr->dead_node, dlm->reco.dead_node);
        dlm_print_reco_node_status(dlm);
        /* this is a hack */
        dlm_put(dlm);
        return -ENOMEM;
    }
    BUG_ON(lr->dead_node != dlm->reco.dead_node);

    item = kzalloc(sizeof(*item), GFP_NOFS);
    if (!item) {
        dlm_put(dlm);
        return -ENOMEM;
    }

    /* this will get freed by dlm_request_all_locks_worker */
    buf = (char *) __get_free_page(GFP_NOFS);
    if (!buf) {
        kfree(item);
        dlm_put(dlm);
        return -ENOMEM;
    }

    /* queue up work for dlm_request_all_locks_worker */
    dlm_grab(dlm);  /* get an extra ref for the work item */
    dlm_init_work_item(dlm, item, dlm_request_all_locks_worker, buf);
    item->u.ral.reco_master = lr->node_idx;
    item->u.ral.dead_node = lr->dead_node;
    spin_lock(&dlm->work_lock);
    list_add_tail(&item->list, &dlm->work_list);
    spin_unlock(&dlm->work_lock);
    queue_work(dlm->dlm_worker, &dlm->dispatched_work);

    dlm_put(dlm);
    return 0;
}

static void dlm_request_all_locks_worker(struct dlm_work_item *item, void *data)
{
    struct dlm_migratable_lockres *mres;
    struct dlm_lock_resource *res;
    struct dlm_ctxt *dlm;
    LIST_HEAD(resources);
    int ret;
    u8 dead_node, reco_master;
    int skip_all_done = 0;

    dlm = item->dlm;
    dead_node = item->u.ral.dead_node;
    reco_master = item->u.ral.reco_master;
    mres = (struct dlm_migratable_lockres *)data;

    mlog(0, "%s: recovery worker started, dead=%u, master=%u\n",
         dlm->name, dead_node, reco_master);

    if (dead_node != dlm->reco.dead_node ||
        reco_master != dlm->reco.new_master) {
        /* worker could have been created before the recovery master
         * died.  if so, do not continue, but do not error. */
        if (dlm->reco.new_master == O2NM_INVALID_NODE_NUM) {
            mlog(ML_NOTICE, "%s: will not send recovery state, "
                 "recovery master %u died, thread=(dead=%u,mas=%u)"
                 " current=(dead=%u,mas=%u)\n", dlm->name,
                 reco_master, dead_node, reco_master,
                 dlm->reco.dead_node, dlm->reco.new_master);
        } else {
            mlog(ML_NOTICE, "%s: reco state invalid: reco(dead=%u, "
                 "master=%u), request(dead=%u, master=%u)\n",
                 dlm->name, dlm->reco.dead_node,
                 dlm->reco.new_master, dead_node, reco_master);
        }
        goto leave;
    }

    /* lock resources should have already been moved to the
     * dlm->reco.resources list.  now move items from that list
     * to a temp list if the dead owner matches.  note that the
     * whole cluster recovers only one node at a time, so we
     * can safely move UNKNOWN lock resources for each recovery
     * session. */
    dlm_move_reco_locks_to_list(dlm, &resources, dead_node);

    /* now we can begin blasting lockreses without the dlm lock */

    /* any errors returned will be due to the new_master dying,
     * the dlm_reco_thread should detect this */
    list_for_each_entry(res, &resources, recovering) {
        ret = dlm_send_one_lockres(dlm, res, mres, reco_master,
                    DLM_MRES_RECOVERY);
        if (ret < 0) {
            mlog(ML_ERROR, "%s: node %u went down while sending "
                 "recovery state for dead node %u, ret=%d\n", dlm->name,
                 reco_master, dead_node, ret);
            skip_all_done = 1;
            break;
        }
    }

    /* move the resources back to the list */
    spin_lock(&dlm->spinlock);
    list_splice_init(&resources, &dlm->reco.resources);
    spin_unlock(&dlm->spinlock);

    if (!skip_all_done) {
        ret = dlm_send_all_done_msg(dlm, dead_node, reco_master);
        if (ret < 0) {
            mlog(ML_ERROR, "%s: node %u went down while sending "
                 "recovery all-done for dead node %u, ret=%d\n",
                 dlm->name, reco_master, dead_node, ret);
        }
    }
leave:
    free_page((unsigned long)data);
}


static int dlm_send_all_done_msg(struct dlm_ctxt *dlm, u8 dead_node, u8 send_to)
{
    int ret, tmpret;
    struct dlm_reco_data_done done_msg;

    memset(&done_msg, 0, sizeof(done_msg));
    done_msg.node_idx = dlm->node_num;
    done_msg.dead_node = dead_node;
    mlog(0, "sending DATA DONE message to %u, "
         "my node=%u, dead node=%u\n", send_to, done_msg.node_idx,
         done_msg.dead_node);

    ret = o2net_send_message(DLM_RECO_DATA_DONE_MSG, dlm->key, &done_msg,
                 sizeof(done_msg), send_to, &tmpret);
    if (ret < 0) {
        mlog(ML_ERROR, "%s: Error %d send RECO_DATA_DONE to node %u "
             "to recover dead node %u\n", dlm->name, ret, send_to,
             dead_node);
        if (!dlm_is_host_down(ret)) {
            BUG();
        }
    } else
        ret = tmpret;
    return ret;
}


int dlm_reco_data_done_handler(struct o2net_msg *msg, u32 len, void *data,
                   void **ret_data)
{
    struct dlm_ctxt *dlm = data;
    struct dlm_reco_data_done *done = (struct dlm_reco_data_done *)msg->buf;
    struct dlm_reco_node_data *ndata = NULL;
    int ret = -EINVAL;

    if (!dlm_grab(dlm))
        return -EINVAL;

    mlog(0, "got DATA DONE: dead_node=%u, reco.dead_node=%u, "
         "node_idx=%u, this node=%u\n", done->dead_node,
         dlm->reco.dead_node, done->node_idx, dlm->node_num);

    mlog_bug_on_msg((done->dead_node != dlm->reco.dead_node),
            "Got DATA DONE: dead_node=%u, reco.dead_node=%u, "
            "node_idx=%u, this node=%u\n", done->dead_node,
            dlm->reco.dead_node, done->node_idx, dlm->node_num);

    spin_lock(&dlm_reco_state_lock);
    list_for_each_entry(ndata, &dlm->reco.node_data, list) {
        if (ndata->node_num != done->node_idx)
            continue;

        switch (ndata->state) {
            /* should have moved beyond INIT but not to FINALIZE yet */
            case DLM_RECO_NODE_DATA_INIT:
            case DLM_RECO_NODE_DATA_DEAD:
            case DLM_RECO_NODE_DATA_FINALIZE_SENT:
                mlog(ML_ERROR, "bad ndata state for node %u:"
                     " state=%d\n", ndata->node_num,
                     ndata->state);
                BUG();
                break;
            /* these states are possible at this point, anywhere along
             * the line of recovery */
            case DLM_RECO_NODE_DATA_DONE:
            case DLM_RECO_NODE_DATA_RECEIVING:
            case DLM_RECO_NODE_DATA_REQUESTED:
            case DLM_RECO_NODE_DATA_REQUESTING:
                mlog(0, "node %u is DONE sending "
                      "recovery data!\n",
                      ndata->node_num);

                ndata->state = DLM_RECO_NODE_DATA_DONE;
                ret = 0;
                break;
        }
    }
    spin_unlock(&dlm_reco_state_lock);

    /* wake the recovery thread, some node is done */
    if (!ret)
        dlm_kick_recovery_thread(dlm);

    if (ret < 0)
        mlog(ML_ERROR, "failed to find recovery node data for node "
             "%u\n", done->node_idx);
    dlm_put(dlm);

    mlog(0, "leaving reco data done handler, ret=%d\n", ret);
    return ret;
}

static void dlm_move_reco_locks_to_list(struct dlm_ctxt *dlm,
                    struct list_head *list,
                        u8 dead_node)
{
    struct dlm_lock_resource *res, *next;
    struct dlm_lock *lock;

    spin_lock(&dlm->spinlock);
    list_for_each_entry_safe(res, next, &dlm->reco.resources, recovering) {
        /* always prune any $RECOVERY entries for dead nodes,
         * otherwise hangs can occur during later recovery */
        if (dlm_is_recovery_lock(res->lockname.name,
                     res->lockname.len)) {
            spin_lock(&res->spinlock);
            list_for_each_entry(lock, &res->granted, list) {
                if (lock->ml.node == dead_node) {
                    mlog(0, "AHA! there was "
                         "a $RECOVERY lock for dead "
                         "node %u (%s)!\n",
                         dead_node, dlm->name);
                    list_del_init(&lock->list);
                    dlm_lock_put(lock);
                    break;
                }
            }
            spin_unlock(&res->spinlock);
            continue;
        }

        if (res->owner == dead_node) {
            mlog(0, "found lockres owned by dead node while "
                  "doing recovery for node %u. sending it.\n",
                  dead_node);
            list_move_tail(&res->recovering, list);
        } else if (res->owner == DLM_LOCK_RES_OWNER_UNKNOWN) {
            mlog(0, "found UNKNOWN owner while doing recovery "
                  "for node %u. sending it.\n", dead_node);
            list_move_tail(&res->recovering, list);
        }
    }
    spin_unlock(&dlm->spinlock);
}

static inline int dlm_num_locks_in_lockres(struct dlm_lock_resource *res)
{
    int total_locks = 0;
    struct list_head *iter, *queue = &res->granted;
    int i;

    for (i=0; i<3; i++) {
        list_for_each(iter, queue)
            total_locks++;
        queue++;
    }
    return total_locks;
}


static int dlm_send_mig_lockres_msg(struct dlm_ctxt *dlm,
                      struct dlm_migratable_lockres *mres,
                      u8 send_to,
                      struct dlm_lock_resource *res,
                      int total_locks)
{
    u64 mig_cookie = be64_to_cpu(mres->mig_cookie);
    int mres_total_locks = be32_to_cpu(mres->total_locks);
    int sz, ret = 0, status = 0;
    u8 orig_flags = mres->flags,
       orig_master = mres->master;

    BUG_ON(mres->num_locks > DLM_MAX_MIGRATABLE_LOCKS);
    if (!mres->num_locks)
        return 0;

    sz = sizeof(struct dlm_migratable_lockres) +
        (mres->num_locks * sizeof(struct dlm_migratable_lock));

    /* add an all-done flag if we reached the last lock */
    orig_flags = mres->flags;
    BUG_ON(total_locks > mres_total_locks);
    if (total_locks == mres_total_locks)
        mres->flags |= DLM_MRES_ALL_DONE;

    mlog(0, "%s:%.*s: sending mig lockres (%s) to %u\n",
         dlm->name, res->lockname.len, res->lockname.name,
         orig_flags & DLM_MRES_MIGRATION ? "migration" : "recovery",
         send_to);

    /* send it */
    ret = o2net_send_message(DLM_MIG_LOCKRES_MSG, dlm->key, mres,
                 sz, send_to, &status);
    if (ret < 0) {
        /* XXX: negative status is not handled.
         * this will end up killing this node. */
        mlog(ML_ERROR, "%s: res %.*s, Error %d send MIG_LOCKRES to "
             "node %u (%s)\n", dlm->name, mres->lockname_len,
             mres->lockname, ret, send_to,
             (orig_flags & DLM_MRES_MIGRATION ?
              "migration" : "recovery"));
    } else {
        /* might get an -ENOMEM back here */
        ret = status;
        if (ret < 0) {
            mlog_errno(ret);

            if (ret == -EFAULT) {
                mlog(ML_ERROR, "node %u told me to kill "
                     "myself!\n", send_to);
                BUG();
            }
        }
    }

    /* zero and reinit the message buffer */
    dlm_init_migratable_lockres(mres, res->lockname.name,
                    res->lockname.len, mres_total_locks,
                    mig_cookie, orig_flags, orig_master);
    return ret;
}

static void dlm_init_migratable_lockres(struct dlm_migratable_lockres *mres,
                    const char *lockname, int namelen,
                    int total_locks, u64 cookie,
                    u8 flags, u8 master)
{
    /* mres here is one full page */
    clear_page(mres);
    mres->lockname_len = namelen;
    memcpy(mres->lockname, lockname, namelen);
    mres->num_locks = 0;
    mres->total_locks = cpu_to_be32(total_locks);
    mres->mig_cookie = cpu_to_be64(cookie);
    mres->flags = flags;
    mres->master = master;
}

static void dlm_prepare_lvb_for_migration(struct dlm_lock *lock,
                      struct dlm_migratable_lockres *mres,
                      int queue)
{
    if (!lock->lksb)
           return;

    /* Ignore lvb in all locks in the blocked list */
    if (queue == DLM_BLOCKED_LIST)
        return;

    /* Only consider lvbs in locks with granted EX or PR lock levels */
    if (lock->ml.type != LKM_EXMODE && lock->ml.type != LKM_PRMODE)
        return;

    if (dlm_lvb_is_empty(mres->lvb)) {
        memcpy(mres->lvb, lock->lksb->lvb, DLM_LVB_LEN);
        return;
    }

    /* Ensure the lvb copied for migration matches in other valid locks */
    if (!memcmp(mres->lvb, lock->lksb->lvb, DLM_LVB_LEN))
        return;

    mlog(ML_ERROR, "Mismatched lvb in lock cookie=%u:%llu, name=%.*s, "
         "node=%u\n",
         dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
         dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)),
         lock->lockres->lockname.len, lock->lockres->lockname.name,
         lock->ml.node);
    dlm_print_one_lock_resource(lock->lockres);
    BUG();
}

/* returns 1 if this lock fills the network structure,
 * 0 otherwise */
static int dlm_add_lock_to_array(struct dlm_lock *lock,
                 struct dlm_migratable_lockres *mres, int queue)
{
    struct dlm_migratable_lock *ml;
    int lock_num = mres->num_locks;

    ml = &(mres->ml[lock_num]);
    ml->cookie = lock->ml.cookie;
    ml->type = lock->ml.type;
    ml->convert_type = lock->ml.convert_type;
    ml->highest_blocked = lock->ml.highest_blocked;
    ml->list = queue;
    if (lock->lksb) {
        ml->flags = lock->lksb->flags;
        dlm_prepare_lvb_for_migration(lock, mres, queue);
    }
    ml->node = lock->ml.node;
    mres->num_locks++;
    /* we reached the max, send this network message */
    if (mres->num_locks == DLM_MAX_MIGRATABLE_LOCKS)
        return 1;
    return 0;
}

static void dlm_add_dummy_lock(struct dlm_ctxt *dlm,
                   struct dlm_migratable_lockres *mres)
{
    struct dlm_lock dummy;
    memset(&dummy, 0, sizeof(dummy));
    dummy.ml.cookie = 0;
    dummy.ml.type = LKM_IVMODE;
    dummy.ml.convert_type = LKM_IVMODE;
    dummy.ml.highest_blocked = LKM_IVMODE;
    dummy.lksb = NULL;
    dummy.ml.node = dlm->node_num;
    dlm_add_lock_to_array(&dummy, mres, DLM_BLOCKED_LIST);
}

static inline int dlm_is_dummy_lock(struct dlm_ctxt *dlm,
                    struct dlm_migratable_lock *ml,
                    u8 *nodenum)
{
    if (unlikely(ml->cookie == 0 &&
        ml->type == LKM_IVMODE &&
        ml->convert_type == LKM_IVMODE &&
        ml->highest_blocked == LKM_IVMODE &&
        ml->list == DLM_BLOCKED_LIST)) {
        *nodenum = ml->node;
        return 1;
    }
    return 0;
}

int dlm_send_one_lockres(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
             struct dlm_migratable_lockres *mres,
             u8 send_to, u8 flags)
{
    struct list_head *queue;
    int total_locks, i;
    u64 mig_cookie = 0;
    struct dlm_lock *lock;
    int ret = 0;

    BUG_ON(!(flags & (DLM_MRES_RECOVERY|DLM_MRES_MIGRATION)));

    mlog(0, "sending to %u\n", send_to);

    total_locks = dlm_num_locks_in_lockres(res);
    if (total_locks > DLM_MAX_MIGRATABLE_LOCKS) {
        /* rare, but possible */
        mlog(0, "argh.  lockres has %d locks.  this will "
              "require more than one network packet to "
              "migrate\n", total_locks);
        mig_cookie = dlm_get_next_mig_cookie();
    }

    dlm_init_migratable_lockres(mres, res->lockname.name,
                    res->lockname.len, total_locks,
                    mig_cookie, flags, res->owner);

    total_locks = 0;
    for (i=DLM_GRANTED_LIST; i<=DLM_BLOCKED_LIST; i++) {
        queue = dlm_list_idx_to_ptr(res, i);
        list_for_each_entry(lock, queue, list) {
            /* add another lock. */
            total_locks++;
            if (!dlm_add_lock_to_array(lock, mres, i))
                continue;

            /* this filled the lock message,
             * we must send it immediately. */
            ret = dlm_send_mig_lockres_msg(dlm, mres, send_to,
                               res, total_locks);
            if (ret < 0)
                goto error;
        }
    }
    if (total_locks == 0) {
        /* send a dummy lock to indicate a mastery reference only */
        mlog(0, "%s:%.*s: sending dummy lock to %u, %s\n",
             dlm->name, res->lockname.len, res->lockname.name,
             send_to, flags & DLM_MRES_RECOVERY ? "recovery" :
             "migration");
        dlm_add_dummy_lock(dlm, mres);
    }
    /* flush any remaining locks */
    ret = dlm_send_mig_lockres_msg(dlm, mres, send_to, res, total_locks);
    if (ret < 0)
        goto error;
    return ret;

error:
    mlog(ML_ERROR, "%s: dlm_send_mig_lockres_msg returned %d\n",
         dlm->name, ret);
    if (!dlm_is_host_down(ret))
        BUG();
    mlog(0, "%s: node %u went down while sending %s "
         "lockres %.*s\n", dlm->name, send_to,
         flags & DLM_MRES_RECOVERY ?  "recovery" : "migration",
         res->lockname.len, res->lockname.name);
    return ret;
}



/*
 * this message will contain no more than one page worth of
 * recovery data, and it will work on only one lockres.
 * there may be many locks in this page, and we may need to wait
 * for additional packets to complete all the locks (rare, but
 * possible).
 */
/*
 * NOTE: the allocation error cases here are scary
 * we really cannot afford to fail an alloc in recovery
 * do we spin?  returning an error only delays the problem really
 */

int dlm_mig_lockres_handler(struct o2net_msg *msg, u32 len, void *data,
                void **ret_data)
{
    struct dlm_ctxt *dlm = data;
    struct dlm_migratable_lockres *mres =
        (struct dlm_migratable_lockres *)msg->buf;
    int ret = 0;
    u8 real_master;
    u8 extra_refs = 0;
    char *buf = NULL;
    struct dlm_work_item *item = NULL;
    struct dlm_lock_resource *res = NULL;

    if (!dlm_grab(dlm))
        return -EINVAL;

    BUG_ON(!(mres->flags & (DLM_MRES_RECOVERY|DLM_MRES_MIGRATION)));

    real_master = mres->master;
    if (real_master == DLM_LOCK_RES_OWNER_UNKNOWN) {
        /* cannot migrate a lockres with no master */
        BUG_ON(!(mres->flags & DLM_MRES_RECOVERY));
    }

    mlog(0, "%s message received from node %u\n",
          (mres->flags & DLM_MRES_RECOVERY) ?
          "recovery" : "migration", mres->master);
    if (mres->flags & DLM_MRES_ALL_DONE)
        mlog(0, "all done flag.  all lockres data received!\n");

    ret = -ENOMEM;
    buf = kmalloc(be16_to_cpu(msg->data_len), GFP_NOFS);
    item = kzalloc(sizeof(*item), GFP_NOFS);
    if (!buf || !item)
        goto leave;

    /* lookup the lock to see if we have a secondary queue for this
     * already...  just add the locks in and this will have its owner
     * and RECOVERY flag changed when it completes. */
    res = dlm_lookup_lockres(dlm, mres->lockname, mres->lockname_len);
    if (res) {
        /* this will get a ref on res */
        /* mark it as recovering/migrating and hash it */
        spin_lock(&res->spinlock);
        if (mres->flags & DLM_MRES_RECOVERY) {
            res->state |= DLM_LOCK_RES_RECOVERING;
        } else {
            if (res->state & DLM_LOCK_RES_MIGRATING) {
                /* this is at least the second
                 * lockres message */
                mlog(0, "lock %.*s is already migrating\n",
                      mres->lockname_len,
                      mres->lockname);
            } else if (res->state & DLM_LOCK_RES_RECOVERING) {
                /* caller should BUG */
                mlog(ML_ERROR, "node is attempting to migrate "
                     "lock %.*s, but marked as recovering!\n",
                     mres->lockname_len, mres->lockname);
                ret = -EFAULT;
                spin_unlock(&res->spinlock);
                goto leave;
            }
            res->state |= DLM_LOCK_RES_MIGRATING;
        }
        spin_unlock(&res->spinlock);
    } else {
        /* need to allocate, just like if it was
         * mastered here normally  */
        res = dlm_new_lockres(dlm, mres->lockname, mres->lockname_len);
        if (!res)
            goto leave;

        /* to match the ref that we would have gotten if
         * dlm_lookup_lockres had succeeded */
        dlm_lockres_get(res);

        /* mark it as recovering/migrating and hash it */
        if (mres->flags & DLM_MRES_RECOVERY)
            res->state |= DLM_LOCK_RES_RECOVERING;
        else
            res->state |= DLM_LOCK_RES_MIGRATING;

        spin_lock(&dlm->spinlock);
        __dlm_insert_lockres(dlm, res);
        spin_unlock(&dlm->spinlock);

        /* Add an extra ref for this lock-less lockres lest the
         * dlm_thread purges it before we get the chance to add
         * locks to it */
        dlm_lockres_get(res);

        /* There are three refs that need to be put.
         * 1. Taken above.
         * 2. kref_init in dlm_new_lockres()->dlm_init_lockres().
         * 3. dlm_lookup_lockres()
         * The first one is handled at the end of this function. The
         * other two are handled in the worker thread after locks have
         * been attached. Yes, we don't wait for purge time to match
         * kref_init. The lockres will still have atleast one ref
         * added because it is in the hash __dlm_insert_lockres() */
        extra_refs++;

        /* now that the new lockres is inserted,
         * make it usable by other processes */
        spin_lock(&res->spinlock);
        res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
        spin_unlock(&res->spinlock);
        wake_up(&res->wq);
    }

    /* at this point we have allocated everything we need,
     * and we have a hashed lockres with an extra ref and
     * the proper res->state flags. */
    ret = 0;
    spin_lock(&res->spinlock);
    /* drop this either when master requery finds a different master
     * or when a lock is added by the recovery worker */
    dlm_lockres_grab_inflight_ref(dlm, res);
    if (mres->master == DLM_LOCK_RES_OWNER_UNKNOWN) {
        /* migration cannot have an unknown master */
        BUG_ON(!(mres->flags & DLM_MRES_RECOVERY));
        mlog(0, "recovery has passed me a lockres with an "
              "unknown owner.. will need to requery: "
              "%.*s\n", mres->lockname_len, mres->lockname);
    } else {
        /* take a reference now to pin the lockres, drop it
         * when locks are added in the worker */
        dlm_change_lockres_owner(dlm, res, dlm->node_num);
    }
    spin_unlock(&res->spinlock);

    /* queue up work for dlm_mig_lockres_worker */
    dlm_grab(dlm);  /* get an extra ref for the work item */
    memcpy(buf, msg->buf, be16_to_cpu(msg->data_len));  /* copy the whole message */
    dlm_init_work_item(dlm, item, dlm_mig_lockres_worker, buf);
    item->u.ml.lockres = res; /* already have a ref */
    item->u.ml.real_master = real_master;
    item->u.ml.extra_ref = extra_refs;
    spin_lock(&dlm->work_lock);
    list_add_tail(&item->list, &dlm->work_list);
    spin_unlock(&dlm->work_lock);
    queue_work(dlm->dlm_worker, &dlm->dispatched_work);

leave:
    /* One extra ref taken needs to be put here */
    if (extra_refs)
        dlm_lockres_put(res);

    dlm_put(dlm);
    if (ret < 0) {
        if (buf)
            kfree(buf);
        if (item)
            kfree(item);
        mlog_errno(ret);
    }

    return ret;
}


static void dlm_mig_lockres_worker(struct dlm_work_item *item, void *data)
{
    struct dlm_ctxt *dlm;
    struct dlm_migratable_lockres *mres;
    int ret = 0;
    struct dlm_lock_resource *res;
    u8 real_master;
    u8 extra_ref;

    dlm = item->dlm;
    mres = (struct dlm_migratable_lockres *)data;

    res = item->u.ml.lockres;
    real_master = item->u.ml.real_master;
    extra_ref = item->u.ml.extra_ref;

    if (real_master == DLM_LOCK_RES_OWNER_UNKNOWN) {
        /* this case is super-rare. only occurs if
         * node death happens during migration. */
again:
        ret = dlm_lockres_master_requery(dlm, res, &real_master);
        if (ret < 0) {
            mlog(0, "dlm_lockres_master_requery ret=%d\n",
                  ret);
            goto again;
        }
        if (real_master == DLM_LOCK_RES_OWNER_UNKNOWN) {
            mlog(0, "lockres %.*s not claimed.  "
                   "this node will take it.\n",
                   res->lockname.len, res->lockname.name);
        } else {
            spin_lock(&res->spinlock);
            dlm_lockres_drop_inflight_ref(dlm, res);
            spin_unlock(&res->spinlock);
            mlog(0, "master needs to respond to sender "
                  "that node %u still owns %.*s\n",
                  real_master, res->lockname.len,
                  res->lockname.name);
            /* cannot touch this lockres */
            goto leave;
        }
    }

    ret = dlm_process_recovery_data(dlm, res, mres);
    if (ret < 0)
        mlog(0, "dlm_process_recovery_data returned  %d\n", ret);
    else
        mlog(0, "dlm_process_recovery_data succeeded\n");

    if ((mres->flags & (DLM_MRES_MIGRATION|DLM_MRES_ALL_DONE)) ==
                       (DLM_MRES_MIGRATION|DLM_MRES_ALL_DONE)) {
        ret = dlm_finish_migration(dlm, res, mres->master);
        if (ret < 0)
            mlog_errno(ret);
    }

leave:
    /* See comment in dlm_mig_lockres_handler() */
    if (res) {
        if (extra_ref)
            dlm_lockres_put(res);
        dlm_lockres_put(res);
    }
    kfree(data);
}



static int dlm_lockres_master_requery(struct dlm_ctxt *dlm,
                      struct dlm_lock_resource *res,
                      u8 *real_master)
{
    struct dlm_node_iter iter;
    int nodenum;
    int ret = 0;

    *real_master = DLM_LOCK_RES_OWNER_UNKNOWN;

    /* we only reach here if one of the two nodes in a
     * migration died while the migration was in progress.
     * at this point we need to requery the master.  we
     * know that the new_master got as far as creating
     * an mle on at least one node, but we do not know
     * if any nodes had actually cleared the mle and set
     * the master to the new_master.  the old master
     * is supposed to set the owner to UNKNOWN in the
     * event of a new_master death, so the only possible
     * responses that we can get from nodes here are
     * that the master is new_master, or that the master
     * is UNKNOWN.
     * if all nodes come back with UNKNOWN then we know
     * the lock needs remastering here.
     * if any node comes back with a valid master, check
     * to see if that master is the one that we are
     * recovering.  if so, then the new_master died and
     * we need to remaster this lock.  if not, then the
     * new_master survived and that node will respond to
     * other nodes about the owner.
     * if there is an owner, this node needs to dump this
     * lockres and alert the sender that this lockres
     * was rejected. */
    spin_lock(&dlm->spinlock);
    dlm_node_iter_init(dlm->domain_map, &iter);
    spin_unlock(&dlm->spinlock);

    while ((nodenum = dlm_node_iter_next(&iter)) >= 0) {
        /* do not send to self */
        if (nodenum == dlm->node_num)
            continue;
        ret = dlm_do_master_requery(dlm, res, nodenum, real_master);
        if (ret < 0) {
            mlog_errno(ret);
            if (!dlm_is_host_down(ret))
                BUG();
            /* host is down, so answer for that node would be
             * DLM_LOCK_RES_OWNER_UNKNOWN.  continue. */
        }
        if (*real_master != DLM_LOCK_RES_OWNER_UNKNOWN) {
            mlog(0, "lock master is %u\n", *real_master);
            break;
        }
    }
    return ret;
}


int dlm_do_master_requery(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
              u8 nodenum, u8 *real_master)
{
    int ret = -EINVAL;
    struct dlm_master_requery req;
    int status = DLM_LOCK_RES_OWNER_UNKNOWN;

    memset(&req, 0, sizeof(req));
    req.node_idx = dlm->node_num;
    req.namelen = res->lockname.len;
    memcpy(req.name, res->lockname.name, res->lockname.len);

    ret = o2net_send_message(DLM_MASTER_REQUERY_MSG, dlm->key,
                 &req, sizeof(req), nodenum, &status);
    /* XXX: negative status not handled properly here. */
    if (ret < 0)
        mlog(ML_ERROR, "Error %d when sending message %u (key "
             "0x%x) to node %u\n", ret, DLM_MASTER_REQUERY_MSG,
             dlm->key, nodenum);
    else {
        BUG_ON(status < 0);
        BUG_ON(status > DLM_LOCK_RES_OWNER_UNKNOWN);
        *real_master = (u8) (status & 0xff);
        mlog(0, "node %u responded to master requery with %u\n",
              nodenum, *real_master);
        ret = 0;
    }
    return ret;
}


/* this function cannot error, so unless the sending
 * or receiving of the message failed, the owner can
 * be trusted */
int dlm_master_requery_handler(struct o2net_msg *msg, u32 len, void *data,
                   void **ret_data)
{
    struct dlm_ctxt *dlm = data;
    struct dlm_master_requery *req = (struct dlm_master_requery *)msg->buf;
    struct dlm_lock_resource *res = NULL;
    unsigned int hash;
    int master = DLM_LOCK_RES_OWNER_UNKNOWN;
    u32 flags = DLM_ASSERT_MASTER_REQUERY;

    if (!dlm_grab(dlm)) {
        /* since the domain has gone away on this
         * node, the proper response is UNKNOWN */
        return master;
    }

    hash = dlm_lockid_hash(req->name, req->namelen);

    spin_lock(&dlm->spinlock);
    res = __dlm_lookup_lockres(dlm, req->name, req->namelen, hash);
    if (res) {
        spin_lock(&res->spinlock);
        master = res->owner;
        if (master == dlm->node_num) {
            int ret = dlm_dispatch_assert_master(dlm, res,
                                 0, 0, flags);
            if (ret < 0) {
                mlog_errno(-ENOMEM);
                /* retry!? */
                BUG();
            }
        } else /* put.. incase we are not the master */
            dlm_lockres_put(res);
        spin_unlock(&res->spinlock);
    }
    spin_unlock(&dlm->spinlock);

    dlm_put(dlm);
    return master;
}

static inline struct list_head *
dlm_list_num_to_pointer(struct dlm_lock_resource *res, int list_num)
{
    struct list_head *ret;
    BUG_ON(list_num < 0);
    BUG_ON(list_num > 2);
    ret = &(res->granted);
    ret += list_num;
    return ret;
}
/* TODO: do ast flush business
 * TODO: do MIGRATING and RECOVERING spinning
 */

/*
* NOTE about in-flight requests during migration:
*
* Before attempting the migrate, the master has marked the lockres as
* MIGRATING and then flushed all of its pending ASTS.  So any in-flight
* requests either got queued before the MIGRATING flag got set, in which
* case the lock data will reflect the change and a return message is on
* the way, or the request failed to get in before MIGRATING got set.  In
* this case, the caller will be told to spin and wait for the MIGRATING
* flag to be dropped, then recheck the master.
* This holds true for the convert, cancel and unlock cases, and since lvb
* updates are tied to these same messages, it applies to lvb updates as
* well.  For the lock case, there is no way a lock can be on the master
* queue and not be on the secondary queue since the lock is always added
* locally first.  This means that the new target node will never be sent
* a lock that he doesn't already have on the list.
* In total, this means that the local lock is correct and should not be
* updated to match the one sent by the master.  Any messages sent back
* from the master before the MIGRATING flag will bring the lock properly
* up-to-date, and the change will be ordered properly for the waiter.
* We will *not* attempt to modify the lock underneath the waiter.
*/

static int dlm_process_recovery_data(struct dlm_ctxt *dlm,
                     struct dlm_lock_resource *res,
                     struct dlm_migratable_lockres *mres)
{
    struct dlm_migratable_lock *ml;
    struct list_head *queue;
    struct list_head *tmpq = NULL;
    struct dlm_lock *newlock = NULL;
    struct dlm_lockstatus *lksb = NULL;
    int ret = 0;
    int i, j, bad;
    struct dlm_lock *lock = NULL;
    u8 from = O2NM_MAX_NODES;
    unsigned int added = 0;
    __be64 c;

    mlog(0, "running %d locks for this lockres\n", mres->num_locks);
    for (i=0; i<mres->num_locks; i++) {
        ml = &(mres->ml[i]);

        if (dlm_is_dummy_lock(dlm, ml, &from)) {
            /* placeholder, just need to set the refmap bit */
            BUG_ON(mres->num_locks != 1);
            mlog(0, "%s:%.*s: dummy lock for %u\n",
                 dlm->name, mres->lockname_len, mres->lockname,
                 from);
            spin_lock(&res->spinlock);
            dlm_lockres_set_refmap_bit(dlm, res, from);
            spin_unlock(&res->spinlock);
            added++;
            break;
        }
        BUG_ON(ml->highest_blocked != LKM_IVMODE);
        newlock = NULL;
        lksb = NULL;

        queue = dlm_list_num_to_pointer(res, ml->list);
        tmpq = NULL;

        /* if the lock is for the local node it needs to
         * be moved to the proper location within the queue.
         * do not allocate a new lock structure. */
        if (ml->node == dlm->node_num) {
            /* MIGRATION ONLY! */
            BUG_ON(!(mres->flags & DLM_MRES_MIGRATION));

            spin_lock(&res->spinlock);
            for (j = DLM_GRANTED_LIST; j <= DLM_BLOCKED_LIST; j++) {
                tmpq = dlm_list_idx_to_ptr(res, j);
                list_for_each_entry(lock, tmpq, list) {
                    if (lock->ml.cookie != ml->cookie)
                        lock = NULL;
                    else
                        break;
                }
                if (lock)
                    break;
            }

            /* lock is always created locally first, and
             * destroyed locally last.  it must be on the list */
            if (!lock) {
                c = ml->cookie;
                mlog(ML_ERROR, "Could not find local lock "
                           "with cookie %u:%llu, node %u, "
                           "list %u, flags 0x%x, type %d, "
                           "conv %d, highest blocked %d\n",
                     dlm_get_lock_cookie_node(be64_to_cpu(c)),
                     dlm_get_lock_cookie_seq(be64_to_cpu(c)),
                     ml->node, ml->list, ml->flags, ml->type,
                     ml->convert_type, ml->highest_blocked);
                __dlm_print_one_lock_resource(res);
                BUG();
            }

            if (lock->ml.node != ml->node) {
                c = lock->ml.cookie;
                mlog(ML_ERROR, "Mismatched node# in lock "
                     "cookie %u:%llu, name %.*s, node %u\n",
                     dlm_get_lock_cookie_node(be64_to_cpu(c)),
                     dlm_get_lock_cookie_seq(be64_to_cpu(c)),
                     res->lockname.len, res->lockname.name,
                     lock->ml.node);
                c = ml->cookie;
                mlog(ML_ERROR, "Migrate lock cookie %u:%llu, "
                     "node %u, list %u, flags 0x%x, type %d, "
                     "conv %d, highest blocked %d\n",
                     dlm_get_lock_cookie_node(be64_to_cpu(c)),
                     dlm_get_lock_cookie_seq(be64_to_cpu(c)),
                     ml->node, ml->list, ml->flags, ml->type,
                     ml->convert_type, ml->highest_blocked);
                __dlm_print_one_lock_resource(res);
                BUG();
            }

            if (tmpq != queue) {
                c = ml->cookie;
                mlog(0, "Lock cookie %u:%llu was on list %u "
                     "instead of list %u for %.*s\n",
                     dlm_get_lock_cookie_node(be64_to_cpu(c)),
                     dlm_get_lock_cookie_seq(be64_to_cpu(c)),
                     j, ml->list, res->lockname.len,
                     res->lockname.name);
                __dlm_print_one_lock_resource(res);
                spin_unlock(&res->spinlock);
                continue;
            }

            /* see NOTE above about why we do not update
             * to match the master here */

            /* move the lock to its proper place */
            /* do not alter lock refcount.  switching lists. */
            list_move_tail(&lock->list, queue);
            spin_unlock(&res->spinlock);
            added++;

            mlog(0, "just reordered a local lock!\n");
            continue;
        }

        /* lock is for another node. */
        newlock = dlm_new_lock(ml->type, ml->node,
                       be64_to_cpu(ml->cookie), NULL);
        if (!newlock) {
            ret = -ENOMEM;
            goto leave;
        }
        lksb = newlock->lksb;
        dlm_lock_attach_lockres(newlock, res);

        if (ml->convert_type != LKM_IVMODE) {
            BUG_ON(queue != &res->converting);
            newlock->ml.convert_type = ml->convert_type;
        }
        lksb->flags |= (ml->flags &
                (DLM_LKSB_PUT_LVB|DLM_LKSB_GET_LVB));

        if (ml->type == LKM_NLMODE)
            goto skip_lvb;

        if (!dlm_lvb_is_empty(mres->lvb)) {
            if (lksb->flags & DLM_LKSB_PUT_LVB) {
                /* other node was trying to update
                 * lvb when node died.  recreate the
                 * lksb with the updated lvb. */
                memcpy(lksb->lvb, mres->lvb, DLM_LVB_LEN);
                /* the lock resource lvb update must happen
                 * NOW, before the spinlock is dropped.
                 * we no longer wait for the AST to update
                 * the lvb. */
                memcpy(res->lvb, mres->lvb, DLM_LVB_LEN);
            } else {
                /* otherwise, the node is sending its
                 * most recent valid lvb info */
                BUG_ON(ml->type != LKM_EXMODE &&
                       ml->type != LKM_PRMODE);
                if (!dlm_lvb_is_empty(res->lvb) &&
                    (ml->type == LKM_EXMODE ||
                     memcmp(res->lvb, mres->lvb, DLM_LVB_LEN))) {
                    int i;
                    mlog(ML_ERROR, "%s:%.*s: received bad "
                         "lvb! type=%d\n", dlm->name,
                         res->lockname.len,
                         res->lockname.name, ml->type);
                    printk("lockres lvb=[");
                    for (i=0; i<DLM_LVB_LEN; i++)
                        printk("%02x", res->lvb[i]);
                    printk("]\nmigrated lvb=[");
                    for (i=0; i<DLM_LVB_LEN; i++)
                        printk("%02x", mres->lvb[i]);
                    printk("]\n");
                    dlm_print_one_lock_resource(res);
                    BUG();
                }
                memcpy(res->lvb, mres->lvb, DLM_LVB_LEN);
            }
        }
skip_lvb:

        /* NOTE:
         * wrt lock queue ordering and recovery:
         *    1. order of locks on granted queue is
         *       meaningless.
         *    2. order of locks on converting queue is
         *       LOST with the node death.  sorry charlie.
         *    3. order of locks on the blocked queue is
         *       also LOST.
         * order of locks does not affect integrity, it
         * just means that a lock request may get pushed
         * back in line as a result of the node death.
         * also note that for a given node the lock order
         * for its secondary queue locks is preserved
         * relative to each other, but clearly *not*
         * preserved relative to locks from other nodes.
         */
        bad = 0;
        spin_lock(&res->spinlock);
        list_for_each_entry(lock, queue, list) {
            if (lock->ml.cookie == ml->cookie) {
                c = lock->ml.cookie;
                mlog(ML_ERROR, "%s:%.*s: %u:%llu: lock already "
                     "exists on this lockres!\n", dlm->name,
                     res->lockname.len, res->lockname.name,
                     dlm_get_lock_cookie_node(be64_to_cpu(c)),
                     dlm_get_lock_cookie_seq(be64_to_cpu(c)));

                mlog(ML_NOTICE, "sent lock: type=%d, conv=%d, "
                     "node=%u, cookie=%u:%llu, queue=%d\n",
                         ml->type, ml->convert_type, ml->node,
                     dlm_get_lock_cookie_node(be64_to_cpu(ml->cookie)),
                     dlm_get_lock_cookie_seq(be64_to_cpu(ml->cookie)),
                     ml->list);

                __dlm_print_one_lock_resource(res);
                bad = 1;
                break;
            }
        }
        if (!bad) {
            dlm_lock_get(newlock);
            list_add_tail(&newlock->list, queue);
            mlog(0, "%s:%.*s: added lock for node %u, "
                 "setting refmap bit\n", dlm->name,
                 res->lockname.len, res->lockname.name, ml->node);
            dlm_lockres_set_refmap_bit(dlm, res, ml->node);
            added++;
        }
        spin_unlock(&res->spinlock);
    }
    mlog(0, "done running all the locks\n");

leave:
    /* balance the ref taken when the work was queued */
    spin_lock(&res->spinlock);
    dlm_lockres_drop_inflight_ref(dlm, res);
    spin_unlock(&res->spinlock);

    if (ret < 0) {
        mlog_errno(ret);
        if (newlock)
            dlm_lock_put(newlock);
    }

    return ret;
}

void dlm_move_lockres_to_recovery_list(struct dlm_ctxt *dlm,
                       struct dlm_lock_resource *res)
{
    int i;
    struct list_head *queue;
    struct dlm_lock *lock, *next;

    assert_spin_locked(&dlm->spinlock);
    assert_spin_locked(&res->spinlock);
    res->state |= DLM_LOCK_RES_RECOVERING;
    if (!list_empty(&res->recovering)) {
        mlog(0,
             "Recovering res %s:%.*s, is already on recovery list!\n",
             dlm->name, res->lockname.len, res->lockname.name);
        list_del_init(&res->recovering);
        dlm_lockres_put(res);
    }
    /* We need to hold a reference while on the recovery list */
    dlm_lockres_get(res);
    list_add_tail(&res->recovering, &dlm->reco.resources);

    /* find any pending locks and put them back on proper list */
    for (i=DLM_BLOCKED_LIST; i>=DLM_GRANTED_LIST; i--) {
        queue = dlm_list_idx_to_ptr(res, i);
        list_for_each_entry_safe(lock, next, queue, list) {
            dlm_lock_get(lock);
            if (lock->convert_pending) {
                /* move converting lock back to granted */
                BUG_ON(i != DLM_CONVERTING_LIST);
                mlog(0, "node died with convert pending "
                     "on %.*s. move back to granted list.\n",
                     res->lockname.len, res->lockname.name);
                dlm_revert_pending_convert(res, lock);
                lock->convert_pending = 0;
            } else if (lock->lock_pending) {
                /* remove pending lock requests completely */
                BUG_ON(i != DLM_BLOCKED_LIST);
                mlog(0, "node died with lock pending "
                     "on %.*s. remove from blocked list and skip.\n",
                     res->lockname.len, res->lockname.name);
                /* lock will be floating until ref in
                 * dlmlock_remote is freed after the network
                 * call returns.  ok for it to not be on any
                 * list since no ast can be called
                 * (the master is dead). */
                dlm_revert_pending_lock(res, lock);
                lock->lock_pending = 0;
            } else if (lock->unlock_pending) {
                /* if an unlock was in progress, treat as
                 * if this had completed successfully
                 * before sending this lock state to the
                 * new master.  note that the dlm_unlock
                 * call is still responsible for calling
                 * the unlockast.  that will happen after
                 * the network call times out.  for now,
                 * just move lists to prepare the new
                 * recovery master.  */
                BUG_ON(i != DLM_GRANTED_LIST);
                mlog(0, "node died with unlock pending "
                     "on %.*s. remove from blocked list and skip.\n",
                     res->lockname.len, res->lockname.name);
                dlm_commit_pending_unlock(res, lock);
                lock->unlock_pending = 0;
            } else if (lock->cancel_pending) {
                /* if a cancel was in progress, treat as
                 * if this had completed successfully
                 * before sending this lock state to the
                 * new master */
                BUG_ON(i != DLM_CONVERTING_LIST);
                mlog(0, "node died with cancel pending "
                     "on %.*s. move back to granted list.\n",
                     res->lockname.len, res->lockname.name);
                dlm_commit_pending_cancel(res, lock);
                lock->cancel_pending = 0;
            }
            dlm_lock_put(lock);
        }
    }
}



/* removes all recovered locks from the recovery list.
 * sets the res->owner to the new master.
 * unsets the RECOVERY flag and wakes waiters. */
static void dlm_finish_local_lockres_recovery(struct dlm_ctxt *dlm,
                          u8 dead_node, u8 new_master)
{
    int i;
    struct hlist_node *hash_iter;
    struct hlist_head *bucket;
    struct dlm_lock_resource *res, *next;

    assert_spin_locked(&dlm->spinlock);

    list_for_each_entry_safe(res, next, &dlm->reco.resources, recovering) {
        if (res->owner == dead_node) {
            mlog(0, "%s: res %.*s, Changing owner from %u to %u\n",
                 dlm->name, res->lockname.len, res->lockname.name,
                 res->owner, new_master);
            list_del_init(&res->recovering);
            spin_lock(&res->spinlock);
            /* new_master has our reference from
             * the lock state sent during recovery */
            dlm_change_lockres_owner(dlm, res, new_master);
            res->state &= ~DLM_LOCK_RES_RECOVERING;
            if (__dlm_lockres_has_locks(res))
                __dlm_dirty_lockres(dlm, res);
            spin_unlock(&res->spinlock);
            wake_up(&res->wq);
            dlm_lockres_put(res);
        }
    }

    /* this will become unnecessary eventually, but
     * for now we need to run the whole hash, clear
     * the RECOVERING state and set the owner
     * if necessary */
    for (i = 0; i < DLM_HASH_BUCKETS; i++) {
        bucket = dlm_lockres_hash(dlm, i);
        hlist_for_each_entry(res, hash_iter, bucket, hash_node) {
            if (!(res->state & DLM_LOCK_RES_RECOVERING))
                continue;

            if (res->owner != dead_node &&
                res->owner != dlm->node_num)
                continue;

            if (!list_empty(&res->recovering)) {
                list_del_init(&res->recovering);
                dlm_lockres_put(res);
            }

            /* new_master has our reference from
             * the lock state sent during recovery */
            mlog(0, "%s: res %.*s, Changing owner from %u to %u\n",
                 dlm->name, res->lockname.len, res->lockname.name,
                 res->owner, new_master);
            spin_lock(&res->spinlock);
            dlm_change_lockres_owner(dlm, res, new_master);
            res->state &= ~DLM_LOCK_RES_RECOVERING;
            if (__dlm_lockres_has_locks(res))
                __dlm_dirty_lockres(dlm, res);
            spin_unlock(&res->spinlock);
            wake_up(&res->wq);
        }
    }
}

static inline int dlm_lvb_needs_invalidation(struct dlm_lock *lock, int local)
{
    if (local) {
        if (lock->ml.type != LKM_EXMODE &&
            lock->ml.type != LKM_PRMODE)
            return 1;
    } else if (lock->ml.type == LKM_EXMODE)
        return 1;
    return 0;
}

static void dlm_revalidate_lvb(struct dlm_ctxt *dlm,
                   struct dlm_lock_resource *res, u8 dead_node)
{
    struct list_head *queue;
    struct dlm_lock *lock;
    int blank_lvb = 0, local = 0;
    int i;
    u8 search_node;

    assert_spin_locked(&dlm->spinlock);
    assert_spin_locked(&res->spinlock);

    if (res->owner == dlm->node_num)
        /* if this node owned the lockres, and if the dead node
         * had an EX when he died, blank out the lvb */
        search_node = dead_node;
    else {
        /* if this is a secondary lockres, and we had no EX or PR
         * locks granted, we can no longer trust the lvb */
        search_node = dlm->node_num;
        local = 1;  /* check local state for valid lvb */
    }

    for (i=DLM_GRANTED_LIST; i<=DLM_CONVERTING_LIST; i++) {
        queue = dlm_list_idx_to_ptr(res, i);
        list_for_each_entry(lock, queue, list) {
            if (lock->ml.node == search_node) {
                if (dlm_lvb_needs_invalidation(lock, local)) {
                    /* zero the lksb lvb and lockres lvb */
                    blank_lvb = 1;
                    memset(lock->lksb->lvb, 0, DLM_LVB_LEN);
                }
            }
        }
    }

    if (blank_lvb) {
        mlog(0, "clearing %.*s lvb, dead node %u had EX\n",
             res->lockname.len, res->lockname.name, dead_node);
        memset(res->lvb, 0, DLM_LVB_LEN);
    }
}

static void dlm_free_dead_locks(struct dlm_ctxt *dlm,
                struct dlm_lock_resource *res, u8 dead_node)
{
    struct dlm_lock *lock, *next;
    unsigned int freed = 0;

    /* this node is the lockres master:
     * 1) remove any stale locks for the dead node
     * 2) if the dead node had an EX when he died, blank out the lvb
     */
    assert_spin_locked(&dlm->spinlock);
    assert_spin_locked(&res->spinlock);

    /* We do two dlm_lock_put(). One for removing from list and the other is
     * to force the DLM_UNLOCK_FREE_LOCK action so as to free the locks */

    /* TODO: check pending_asts, pending_basts here */
    list_for_each_entry_safe(lock, next, &res->granted, list) {
        if (lock->ml.node == dead_node) {
            list_del_init(&lock->list);
            dlm_lock_put(lock);
            /* Can't schedule DLM_UNLOCK_FREE_LOCK - do manually */
            dlm_lock_put(lock);
            freed++;
        }
    }
    list_for_each_entry_safe(lock, next, &res->converting, list) {
        if (lock->ml.node == dead_node) {
            list_del_init(&lock->list);
            dlm_lock_put(lock);
            /* Can't schedule DLM_UNLOCK_FREE_LOCK - do manually */
            dlm_lock_put(lock);
            freed++;
        }
    }
    list_for_each_entry_safe(lock, next, &res->blocked, list) {
        if (lock->ml.node == dead_node) {
            list_del_init(&lock->list);
            dlm_lock_put(lock);
            /* Can't schedule DLM_UNLOCK_FREE_LOCK - do manually */
            dlm_lock_put(lock);
            freed++;
        }
    }

    if (freed) {
        mlog(0, "%s:%.*s: freed %u locks for dead node %u, "
             "dropping ref from lockres\n", dlm->name,
             res->lockname.len, res->lockname.name, freed, dead_node);
        if(!test_bit(dead_node, res->refmap)) {
            mlog(ML_ERROR, "%s:%.*s: freed %u locks for dead node %u, "
                 "but ref was not set\n", dlm->name,
                 res->lockname.len, res->lockname.name, freed, dead_node);
            __dlm_print_one_lock_resource(res);
        }
        dlm_lockres_clear_refmap_bit(dlm, res, dead_node);
    } else if (test_bit(dead_node, res->refmap)) {
        mlog(0, "%s:%.*s: dead node %u had a ref, but had "
             "no locks and had not purged before dying\n", dlm->name,
             res->lockname.len, res->lockname.name, dead_node);
        dlm_lockres_clear_refmap_bit(dlm, res, dead_node);
    }

    /* do not kick thread yet */
    __dlm_dirty_lockres(dlm, res);
}

/* if this node is the recovery master, and there are no
 * locks for a given lockres owned by this node that are in
 * either PR or EX mode, zero out the lvb before requesting.
 *
 */


static void dlm_do_local_recovery_cleanup(struct dlm_ctxt *dlm, u8 dead_node)
{
    struct hlist_node *iter;
    struct dlm_lock_resource *res;
    int i;
    struct hlist_head *bucket;
    struct dlm_lock *lock;


    /* purge any stale mles */
    dlm_clean_master_list(dlm, dead_node);

    /*
     * now clean up all lock resources.  there are two rules:
     *
     * 1) if the dead node was the master, move the lockres
     *    to the recovering list.  set the RECOVERING flag.
     *    this lockres needs to be cleaned up before it can
     *    be used further.
     *
     * 2) if this node was the master, remove all locks from
     *    each of the lockres queues that were owned by the
     *    dead node.  once recovery finishes, the dlm thread
     *    can be kicked again to see if any ASTs or BASTs
     *    need to be fired as a result.
     */
    for (i = 0; i < DLM_HASH_BUCKETS; i++) {
        bucket = dlm_lockres_hash(dlm, i);
        hlist_for_each_entry(res, iter, bucket, hash_node) {
            /* always prune any $RECOVERY entries for dead nodes,
             * otherwise hangs can occur during later recovery */
            if (dlm_is_recovery_lock(res->lockname.name,
                         res->lockname.len)) {
                spin_lock(&res->spinlock);
                list_for_each_entry(lock, &res->granted, list) {
                    if (lock->ml.node == dead_node) {
                        mlog(0, "AHA! there was "
                             "a $RECOVERY lock for dead "
                             "node %u (%s)!\n",
                             dead_node, dlm->name);
                        list_del_init(&lock->list);
                        dlm_lock_put(lock);
                        break;
                    }
                }
                spin_unlock(&res->spinlock);
                continue;
            }
            spin_lock(&res->spinlock);
            /* zero the lvb if necessary */
            dlm_revalidate_lvb(dlm, res, dead_node);
            if (res->owner == dead_node) {
                if (res->state & DLM_LOCK_RES_DROPPING_REF) {
                    mlog(ML_NOTICE, "%s: res %.*s, Skip "
                         "recovery as it is being freed\n",
                         dlm->name, res->lockname.len,
                         res->lockname.name);
                } else
                    dlm_move_lockres_to_recovery_list(dlm,
                                      res);

            } else if (res->owner == dlm->node_num) {
                dlm_free_dead_locks(dlm, res, dead_node);
                __dlm_lockres_calc_usage(dlm, res);
            }
            spin_unlock(&res->spinlock);
        }
    }

}

static void __dlm_hb_node_down(struct dlm_ctxt *dlm, int idx)
{
    assert_spin_locked(&dlm->spinlock);

    if (dlm->reco.new_master == idx) {
        mlog(0, "%s: recovery master %d just died\n",
             dlm->name, idx);
        if (dlm->reco.state & DLM_RECO_STATE_FINALIZE) {
            /* finalize1 was reached, so it is safe to clear
             * the new_master and dead_node.  that recovery
             * is complete. */
            mlog(0, "%s: dead master %d had reached "
                 "finalize1 state, clearing\n", dlm->name, idx);
            dlm->reco.state &= ~DLM_RECO_STATE_FINALIZE;
            __dlm_reset_recovery(dlm);
        }
    }

    /* Clean up join state on node death. */
    if (dlm->joining_node == idx) {
        mlog(0, "Clearing join state for node %u\n", idx);
        __dlm_set_joining_node(dlm, DLM_LOCK_RES_OWNER_UNKNOWN);
    }

    /* check to see if the node is already considered dead */
    if (!test_bit(idx, dlm->live_nodes_map)) {
        mlog(0, "for domain %s, node %d is already dead. "
             "another node likely did recovery already.\n",
             dlm->name, idx);
        return;
    }

    /* check to see if we do not care about this node */
    if (!test_bit(idx, dlm->domain_map)) {
        /* This also catches the case that we get a node down
         * but haven't joined the domain yet. */
        mlog(0, "node %u already removed from domain!\n", idx);
        return;
    }

    clear_bit(idx, dlm->live_nodes_map);

    /* make sure local cleanup occurs before the heartbeat events */
    if (!test_bit(idx, dlm->recovery_map))
        dlm_do_local_recovery_cleanup(dlm, idx);

    /* notify anything attached to the heartbeat events */
    dlm_hb_event_notify_attached(dlm, idx, 0);

    mlog(0, "node %u being removed from domain map!\n", idx);
    clear_bit(idx, dlm->domain_map);
    clear_bit(idx, dlm->exit_domain_map);
    /* wake up migration waiters if a node goes down.
     * perhaps later we can genericize this for other waiters. */
    wake_up(&dlm->migration_wq);

    if (test_bit(idx, dlm->recovery_map))
        mlog(0, "domain %s, node %u already added "
             "to recovery map!\n", dlm->name, idx);
    else
        set_bit(idx, dlm->recovery_map);
}

void dlm_hb_node_down_cb(struct o2nm_node *node, int idx, void *data)
{
    struct dlm_ctxt *dlm = data;

    if (!dlm_grab(dlm))
        return;

    /*
     * This will notify any dlm users that a node in our domain
     * went away without notifying us first.
     */
    if (test_bit(idx, dlm->domain_map))
        dlm_fire_domain_eviction_callbacks(dlm, idx);

    spin_lock(&dlm->spinlock);
    __dlm_hb_node_down(dlm, idx);
    spin_unlock(&dlm->spinlock);

    dlm_put(dlm);
}

void dlm_hb_node_up_cb(struct o2nm_node *node, int idx, void *data)
{
    struct dlm_ctxt *dlm = data;

    if (!dlm_grab(dlm))
        return;

    spin_lock(&dlm->spinlock);
    set_bit(idx, dlm->live_nodes_map);
    /* do NOT notify mle attached to the heartbeat events.
     * new nodes are not interesting in mastery until joined. */
    spin_unlock(&dlm->spinlock);

    dlm_put(dlm);
}

static void dlm_reco_ast(void *astdata)
{
    struct dlm_ctxt *dlm = astdata;
    mlog(0, "ast for recovery lock fired!, this=%u, dlm=%s\n",
         dlm->node_num, dlm->name);
}
static void dlm_reco_bast(void *astdata, int blocked_type)
{
    struct dlm_ctxt *dlm = astdata;
    mlog(0, "bast for recovery lock fired!, this=%u, dlm=%s\n",
         dlm->node_num, dlm->name);
}
static void dlm_reco_unlock_ast(void *astdata, enum dlm_status st)
{
    mlog(0, "unlockast for recovery lock fired!\n");
}

/*
 * dlm_pick_recovery_master will continually attempt to use
 * dlmlock() on the special "$RECOVERY" lockres with the
 * LKM_NOQUEUE flag to get an EX.  every thread that enters
 * this function on each node racing to become the recovery
 * master will not stop attempting this until either:
 * a) this node gets the EX (and becomes the recovery master),
 * or b) dlm->reco.new_master gets set to some nodenum
 * != O2NM_INVALID_NODE_NUM (another node will do the reco).
 * so each time a recovery master is needed, the entire cluster
 * will sync at this point.  if the new master dies, that will
 * be detected in dlm_do_recovery */
static int dlm_pick_recovery_master(struct dlm_ctxt *dlm)
{
    enum dlm_status ret;
    struct dlm_lockstatus lksb;
    int status = -EINVAL;

    mlog(0, "starting recovery of %s at %lu, dead=%u, this=%u\n",
         dlm->name, jiffies, dlm->reco.dead_node, dlm->node_num);
again:
    memset(&lksb, 0, sizeof(lksb));

    ret = dlmlock(dlm, LKM_EXMODE, &lksb, LKM_NOQUEUE|LKM_RECOVERY,
              DLM_RECOVERY_LOCK_NAME, DLM_RECOVERY_LOCK_NAME_LEN,
              dlm_reco_ast, dlm, dlm_reco_bast);

    mlog(0, "%s: dlmlock($RECOVERY) returned %d, lksb=%d\n",
         dlm->name, ret, lksb.status);

    if (ret == DLM_NORMAL) {
        mlog(0, "dlm=%s dlmlock says I got it (this=%u)\n",
             dlm->name, dlm->node_num);

        /* got the EX lock.  check to see if another node
         * just became the reco master */
        if (dlm_reco_master_ready(dlm)) {
            mlog(0, "%s: got reco EX lock, but %u will "
                 "do the recovery\n", dlm->name,
                 dlm->reco.new_master);
            status = -EEXIST;
        } else {
            status = 0;

            /* see if recovery was already finished elsewhere */
            spin_lock(&dlm->spinlock);
            if (dlm->reco.dead_node == O2NM_INVALID_NODE_NUM) {
                status = -EINVAL;
                mlog(0, "%s: got reco EX lock, but "
                     "node got recovered already\n", dlm->name);
                if (dlm->reco.new_master != O2NM_INVALID_NODE_NUM) {
                    mlog(ML_ERROR, "%s: new master is %u "
                         "but no dead node!\n",
                         dlm->name, dlm->reco.new_master);
                    BUG();
                }
            }
            spin_unlock(&dlm->spinlock);
        }

        /* if this node has actually become the recovery master,
         * set the master and send the messages to begin recovery */
        if (!status) {
            mlog(0, "%s: dead=%u, this=%u, sending "
                 "begin_reco now\n", dlm->name,
                 dlm->reco.dead_node, dlm->node_num);
            status = dlm_send_begin_reco_message(dlm,
                      dlm->reco.dead_node);
            /* this always succeeds */
            BUG_ON(status);

            /* set the new_master to this node */
            spin_lock(&dlm->spinlock);
            dlm_set_reco_master(dlm, dlm->node_num);
            spin_unlock(&dlm->spinlock);
        }

        /* recovery lock is a special case.  ast will not get fired,
         * so just go ahead and unlock it. */
        ret = dlmunlock(dlm, &lksb, 0, dlm_reco_unlock_ast, dlm);
        if (ret == DLM_DENIED) {
            mlog(0, "got DLM_DENIED, trying LKM_CANCEL\n");
            ret = dlmunlock(dlm, &lksb, LKM_CANCEL, dlm_reco_unlock_ast, dlm);
        }
        if (ret != DLM_NORMAL) {
            /* this would really suck. this could only happen
             * if there was a network error during the unlock
             * because of node death.  this means the unlock
             * is actually "done" and the lock structure is
             * even freed.  we can continue, but only
             * because this specific lock name is special. */
            mlog(ML_ERROR, "dlmunlock returned %d\n", ret);
        }
    } else if (ret == DLM_NOTQUEUED) {
        mlog(0, "dlm=%s dlmlock says another node got it (this=%u)\n",
             dlm->name, dlm->node_num);
        /* another node is master. wait on
         * reco.new_master != O2NM_INVALID_NODE_NUM
         * for at most one second */
        wait_event_timeout(dlm->dlm_reco_thread_wq,
                     dlm_reco_master_ready(dlm),
                     msecs_to_jiffies(1000));
        if (!dlm_reco_master_ready(dlm)) {
            mlog(0, "%s: reco master taking awhile\n",
                 dlm->name);
            goto again;
        }
        /* another node has informed this one that it is reco master */
        mlog(0, "%s: reco master %u is ready to recover %u\n",
             dlm->name, dlm->reco.new_master, dlm->reco.dead_node);
        status = -EEXIST;
    } else if (ret == DLM_RECOVERING) {
        mlog(0, "dlm=%s dlmlock says master node died (this=%u)\n",
             dlm->name, dlm->node_num);
        goto again;
    } else {
        struct dlm_lock_resource *res;

        /* dlmlock returned something other than NOTQUEUED or NORMAL */
        mlog(ML_ERROR, "%s: got %s from dlmlock($RECOVERY), "
             "lksb.status=%s\n", dlm->name, dlm_errname(ret),
             dlm_errname(lksb.status));
        res = dlm_lookup_lockres(dlm, DLM_RECOVERY_LOCK_NAME,
                     DLM_RECOVERY_LOCK_NAME_LEN);
        if (res) {
            dlm_print_one_lock_resource(res);
            dlm_lockres_put(res);
        } else {
            mlog(ML_ERROR, "recovery lock not found\n");
        }
        BUG();
    }

    return status;
}

static int dlm_send_begin_reco_message(struct dlm_ctxt *dlm, u8 dead_node)
{
    struct dlm_begin_reco br;
    int ret = 0;
    struct dlm_node_iter iter;
    int nodenum;
    int status;

    mlog(0, "%s: dead node is %u\n", dlm->name, dead_node);

    spin_lock(&dlm->spinlock);
    dlm_node_iter_init(dlm->domain_map, &iter);
    spin_unlock(&dlm->spinlock);

    clear_bit(dead_node, iter.node_map);

    memset(&br, 0, sizeof(br));
    br.node_idx = dlm->node_num;
    br.dead_node = dead_node;

    while ((nodenum = dlm_node_iter_next(&iter)) >= 0) {
        ret = 0;
        if (nodenum == dead_node) {
            mlog(0, "not sending begin reco to dead node "
                  "%u\n", dead_node);
            continue;
        }
        if (nodenum == dlm->node_num) {
            mlog(0, "not sending begin reco to self\n");
            continue;
        }
retry:
        ret = -EINVAL;
        mlog(0, "attempting to send begin reco msg to %d\n",
              nodenum);
        ret = o2net_send_message(DLM_BEGIN_RECO_MSG, dlm->key,
                     &br, sizeof(br), nodenum, &status);
        /* negative status is handled ok by caller here */
        if (ret >= 0)
            ret = status;
        if (dlm_is_host_down(ret)) {
            /* node is down.  not involved in recovery
             * so just keep going */
            mlog(ML_NOTICE, "%s: node %u was down when sending "
                 "begin reco msg (%d)\n", dlm->name, nodenum, ret);
            ret = 0;
        }

        /*
         * Prior to commit aad1b15310b9bcd59fa81ab8f2b1513b59553ea8,
         * dlm_begin_reco_handler() returned EAGAIN and not -EAGAIN.
         * We are handling both for compatibility reasons.
         */
        if (ret == -EAGAIN || ret == EAGAIN) {
            mlog(0, "%s: trying to start recovery of node "
                 "%u, but node %u is waiting for last recovery "
                 "to complete, backoff for a bit\n", dlm->name,
                 dead_node, nodenum);
            msleep(100);
            goto retry;
        }
        if (ret < 0) {
            struct dlm_lock_resource *res;

            /* this is now a serious problem, possibly ENOMEM
             * in the network stack.  must retry */
            mlog_errno(ret);
            mlog(ML_ERROR, "begin reco of dlm %s to node %u "
                 "returned %d\n", dlm->name, nodenum, ret);
            res = dlm_lookup_lockres(dlm, DLM_RECOVERY_LOCK_NAME,
                         DLM_RECOVERY_LOCK_NAME_LEN);
            if (res) {
                dlm_print_one_lock_resource(res);
                dlm_lockres_put(res);
            } else {
                mlog(ML_ERROR, "recovery lock not found\n");
            }
            /* sleep for a bit in hopes that we can avoid
             * another ENOMEM */
            msleep(100);
            goto retry;
        }
    }

    return ret;
}

int dlm_begin_reco_handler(struct o2net_msg *msg, u32 len, void *data,
               void **ret_data)
{
    struct dlm_ctxt *dlm = data;
    struct dlm_begin_reco *br = (struct dlm_begin_reco *)msg->buf;

    /* ok to return 0, domain has gone away */
    if (!dlm_grab(dlm))
        return 0;

    spin_lock(&dlm->spinlock);
    if (dlm->reco.state & DLM_RECO_STATE_FINALIZE) {
        mlog(0, "%s: node %u wants to recover node %u (%u:%u) "
             "but this node is in finalize state, waiting on finalize2\n",
             dlm->name, br->node_idx, br->dead_node,
             dlm->reco.dead_node, dlm->reco.new_master);
        spin_unlock(&dlm->spinlock);
        return -EAGAIN;
    }
    spin_unlock(&dlm->spinlock);

    mlog(0, "%s: node %u wants to recover node %u (%u:%u)\n",
         dlm->name, br->node_idx, br->dead_node,
         dlm->reco.dead_node, dlm->reco.new_master);

    dlm_fire_domain_eviction_callbacks(dlm, br->dead_node);

    spin_lock(&dlm->spinlock);
    if (dlm->reco.new_master != O2NM_INVALID_NODE_NUM) {
        if (test_bit(dlm->reco.new_master, dlm->recovery_map)) {
            mlog(0, "%s: new_master %u died, changing "
                 "to %u\n", dlm->name, dlm->reco.new_master,
                 br->node_idx);
        } else {
            mlog(0, "%s: new_master %u NOT DEAD, changing "
                 "to %u\n", dlm->name, dlm->reco.new_master,
                 br->node_idx);
            /* may not have seen the new master as dead yet */
        }
    }
    if (dlm->reco.dead_node != O2NM_INVALID_NODE_NUM) {
        mlog(ML_NOTICE, "%s: dead_node previously set to %u, "
             "node %u changing it to %u\n", dlm->name,
             dlm->reco.dead_node, br->node_idx, br->dead_node);
    }
    dlm_set_reco_master(dlm, br->node_idx);
    dlm_set_reco_dead_node(dlm, br->dead_node);
    if (!test_bit(br->dead_node, dlm->recovery_map)) {
        mlog(0, "recovery master %u sees %u as dead, but this "
             "node has not yet.  marking %u as dead\n",
             br->node_idx, br->dead_node, br->dead_node);
        if (!test_bit(br->dead_node, dlm->domain_map) ||
            !test_bit(br->dead_node, dlm->live_nodes_map))
            mlog(0, "%u not in domain/live_nodes map "
                 "so setting it in reco map manually\n",
                 br->dead_node);
        /* force the recovery cleanup in __dlm_hb_node_down
         * both of these will be cleared in a moment */
        set_bit(br->dead_node, dlm->domain_map);
        set_bit(br->dead_node, dlm->live_nodes_map);
        __dlm_hb_node_down(dlm, br->dead_node);
    }
    spin_unlock(&dlm->spinlock);

    dlm_kick_recovery_thread(dlm);

    mlog(0, "%s: recovery started by node %u, for %u (%u:%u)\n",
         dlm->name, br->node_idx, br->dead_node,
         dlm->reco.dead_node, dlm->reco.new_master);

    dlm_put(dlm);
    return 0;
}

#define DLM_FINALIZE_STAGE2  0x01
static int dlm_send_finalize_reco_message(struct dlm_ctxt *dlm)
{
    int ret = 0;
    struct dlm_finalize_reco fr;
    struct dlm_node_iter iter;
    int nodenum;
    int status;
    int stage = 1;

    mlog(0, "finishing recovery for node %s:%u, "
         "stage %d\n", dlm->name, dlm->reco.dead_node, stage);

    spin_lock(&dlm->spinlock);
    dlm_node_iter_init(dlm->domain_map, &iter);
    spin_unlock(&dlm->spinlock);

stage2:
    memset(&fr, 0, sizeof(fr));
    fr.node_idx = dlm->node_num;
    fr.dead_node = dlm->reco.dead_node;
    if (stage == 2)
        fr.flags |= DLM_FINALIZE_STAGE2;

    while ((nodenum = dlm_node_iter_next(&iter)) >= 0) {
        if (nodenum == dlm->node_num)
            continue;
        ret = o2net_send_message(DLM_FINALIZE_RECO_MSG, dlm->key,
                     &fr, sizeof(fr), nodenum, &status);
        if (ret >= 0)
            ret = status;
        if (ret < 0) {
            mlog(ML_ERROR, "Error %d when sending message %u (key "
                 "0x%x) to node %u\n", ret, DLM_FINALIZE_RECO_MSG,
                 dlm->key, nodenum);
            if (dlm_is_host_down(ret)) {
                /* this has no effect on this recovery
                 * session, so set the status to zero to
                 * finish out the last recovery */
                mlog(ML_ERROR, "node %u went down after this "
                     "node finished recovery.\n", nodenum);
                ret = 0;
                continue;
            }
            break;
        }
    }
    if (stage == 1) {
        /* reset the node_iter back to the top and send finalize2 */
        iter.curnode = -1;
        stage = 2;
        goto stage2;
    }

    return ret;
}

int dlm_finalize_reco_handler(struct o2net_msg *msg, u32 len, void *data,
                  void **ret_data)
{
    struct dlm_ctxt *dlm = data;
    struct dlm_finalize_reco *fr = (struct dlm_finalize_reco *)msg->buf;
    int stage = 1;

    /* ok to return 0, domain has gone away */
    if (!dlm_grab(dlm))
        return 0;

    if (fr->flags & DLM_FINALIZE_STAGE2)
        stage = 2;

    mlog(0, "%s: node %u finalizing recovery stage%d of "
         "node %u (%u:%u)\n", dlm->name, fr->node_idx, stage,
         fr->dead_node, dlm->reco.dead_node, dlm->reco.new_master);

    spin_lock(&dlm->spinlock);

    if (dlm->reco.new_master != fr->node_idx) {
        mlog(ML_ERROR, "node %u sent recovery finalize msg, but node "
             "%u is supposed to be the new master, dead=%u\n",
             fr->node_idx, dlm->reco.new_master, fr->dead_node);
        BUG();
    }
    if (dlm->reco.dead_node != fr->dead_node) {
        mlog(ML_ERROR, "node %u sent recovery finalize msg for dead "
             "node %u, but node %u is supposed to be dead\n",
             fr->node_idx, fr->dead_node, dlm->reco.dead_node);
        BUG();
    }

    switch (stage) {
        case 1:
            dlm_finish_local_lockres_recovery(dlm, fr->dead_node, fr->node_idx);
            if (dlm->reco.state & DLM_RECO_STATE_FINALIZE) {
                mlog(ML_ERROR, "%s: received finalize1 from "
                     "new master %u for dead node %u, but "
                     "this node has already received it!\n",
                     dlm->name, fr->node_idx, fr->dead_node);
                dlm_print_reco_node_status(dlm);
                BUG();
            }
            dlm->reco.state |= DLM_RECO_STATE_FINALIZE;
            spin_unlock(&dlm->spinlock);
            break;
        case 2:
            if (!(dlm->reco.state & DLM_RECO_STATE_FINALIZE)) {
                mlog(ML_ERROR, "%s: received finalize2 from "
                     "new master %u for dead node %u, but "
                     "this node did not have finalize1!\n",
                     dlm->name, fr->node_idx, fr->dead_node);
                dlm_print_reco_node_status(dlm);
                BUG();
            }
            dlm->reco.state &= ~DLM_RECO_STATE_FINALIZE;
            spin_unlock(&dlm->spinlock);
            dlm_reset_recovery(dlm);
            dlm_kick_recovery_thread(dlm);
            break;
        default:
            BUG();
    }

    mlog(0, "%s: recovery done, reco master was %u, dead now %u, master now %u\n",
         dlm->name, fr->node_idx, dlm->reco.dead_node, dlm->reco.new_master);

    dlm_put(dlm);
    return 0;
}