recover.c

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/******************************************************************************
*******************************************************************************
**
**  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
**  Copyright (C) 2004-2005 Red Hat, Inc.  All rights reserved.
**
**  This copyrighted material is made available to anyone wishing to use,
**  modify, copy, or redistribute it subject to the terms and conditions
**  of the GNU General Public License v.2.
**
*******************************************************************************
******************************************************************************/

#include "dlm_internal.h"
#include "lockspace.h"
#include "dir.h"
#include "config.h"
#include "ast.h"
#include "memory.h"
#include "rcom.h"
#include "lock.h"
#include "lowcomms.h"
#include "member.h"
#include "recover.h"


/*
 * Recovery waiting routines: these functions wait for a particular reply from
 * a remote node, or for the remote node to report a certain status.  They need
 * to abort if the lockspace is stopped indicating a node has failed (perhaps
 * the one being waited for).
 */

/*
 * Wait until given function returns non-zero or lockspace is stopped
 * (LS_RECOVERY_STOP set due to failure of a node in ls_nodes).  When another
 * function thinks it could have completed the waited-on task, they should wake
 * up ls_wait_general to get an immediate response rather than waiting for the
 * timeout.  This uses a timeout so it can check periodically if the wait
 * should abort due to node failure (which doesn't cause a wake_up).
 * This should only be called by the dlm_recoverd thread.
 */

int dlm_wait_function(struct dlm_ls *ls, int (*testfn) (struct dlm_ls *ls))
{
    int error = 0;
    int rv;

    while (1) {
        rv = wait_event_timeout(ls->ls_wait_general,
                    testfn(ls) || dlm_recovery_stopped(ls),
                    dlm_config.ci_recover_timer * HZ);
        if (rv)
            break;
    }

    if (dlm_recovery_stopped(ls)) {
        log_debug(ls, "dlm_wait_function aborted");
        error = -EINTR;
    }
    return error;
}

/*
 * An efficient way for all nodes to wait for all others to have a certain
 * status.  The node with the lowest nodeid polls all the others for their
 * status (wait_status_all) and all the others poll the node with the low id
 * for its accumulated result (wait_status_low).  When all nodes have set
 * status flag X, then status flag X_ALL will be set on the low nodeid.
 */

uint32_t dlm_recover_status(struct dlm_ls *ls)
{
    uint32_t status;
    spin_lock(&ls->ls_recover_lock);
    status = ls->ls_recover_status;
    spin_unlock(&ls->ls_recover_lock);
    return status;
}

static void _set_recover_status(struct dlm_ls *ls, uint32_t status)
{
    ls->ls_recover_status |= status;
}

void dlm_set_recover_status(struct dlm_ls *ls, uint32_t status)
{
    spin_lock(&ls->ls_recover_lock);
    _set_recover_status(ls, status);
    spin_unlock(&ls->ls_recover_lock);
}

static int wait_status_all(struct dlm_ls *ls, uint32_t wait_status,
               int save_slots)
{
    struct dlm_rcom *rc = ls->ls_recover_buf;
    struct dlm_member *memb;
    int error = 0, delay;

    list_for_each_entry(memb, &ls->ls_nodes, list) {
        delay = 0;
        for (;;) {
            if (dlm_recovery_stopped(ls)) {
                error = -EINTR;
                goto out;
            }

            error = dlm_rcom_status(ls, memb->nodeid, 0);
            if (error)
                goto out;

            if (save_slots)
                dlm_slot_save(ls, rc, memb);

            if (rc->rc_result & wait_status)
                break;
            if (delay < 1000)
                delay += 20;
            msleep(delay);
        }
    }
 out:
    return error;
}

static int wait_status_low(struct dlm_ls *ls, uint32_t wait_status,
               uint32_t status_flags)
{
    struct dlm_rcom *rc = ls->ls_recover_buf;
    int error = 0, delay = 0, nodeid = ls->ls_low_nodeid;

    for (;;) {
        if (dlm_recovery_stopped(ls)) {
            error = -EINTR;
            goto out;
        }

        error = dlm_rcom_status(ls, nodeid, status_flags);
        if (error)
            break;

        if (rc->rc_result & wait_status)
            break;
        if (delay < 1000)
            delay += 20;
        msleep(delay);
    }
 out:
    return error;
}

static int wait_status(struct dlm_ls *ls, uint32_t status)
{
    uint32_t status_all = status << 1;
    int error;

    if (ls->ls_low_nodeid == dlm_our_nodeid()) {
        error = wait_status_all(ls, status, 0);
        if (!error)
            dlm_set_recover_status(ls, status_all);
    } else
        error = wait_status_low(ls, status_all, 0);

    return error;
}

int dlm_recover_members_wait(struct dlm_ls *ls)
{
    struct dlm_member *memb;
    struct dlm_slot *slots;
    int num_slots, slots_size;
    int error, rv;
    uint32_t gen;

    list_for_each_entry(memb, &ls->ls_nodes, list) {
        memb->slot = -1;
        memb->generation = 0;
    }

    if (ls->ls_low_nodeid == dlm_our_nodeid()) {
        error = wait_status_all(ls, DLM_RS_NODES, 1);
        if (error)
            goto out;

        /* slots array is sparse, slots_size may be > num_slots */

        rv = dlm_slots_assign(ls, &num_slots, &slots_size, &slots, &gen);
        if (!rv) {
            spin_lock(&ls->ls_recover_lock);
            _set_recover_status(ls, DLM_RS_NODES_ALL);
            ls->ls_num_slots = num_slots;
            ls->ls_slots_size = slots_size;
            ls->ls_slots = slots;
            ls->ls_generation = gen;
            spin_unlock(&ls->ls_recover_lock);
        } else {
            dlm_set_recover_status(ls, DLM_RS_NODES_ALL);
        }
    } else {
        error = wait_status_low(ls, DLM_RS_NODES_ALL, DLM_RSF_NEED_SLOTS);
        if (error)
            goto out;

        dlm_slots_copy_in(ls);
    }
 out:
    return error;
}

int dlm_recover_directory_wait(struct dlm_ls *ls)
{
    return wait_status(ls, DLM_RS_DIR);
}

int dlm_recover_locks_wait(struct dlm_ls *ls)
{
    return wait_status(ls, DLM_RS_LOCKS);
}

int dlm_recover_done_wait(struct dlm_ls *ls)
{
    return wait_status(ls, DLM_RS_DONE);
}

/*
 * The recover_list contains all the rsb's for which we've requested the new
 * master nodeid.  As replies are returned from the resource directories the
 * rsb's are removed from the list.  When the list is empty we're done.
 *
 * The recover_list is later similarly used for all rsb's for which we've sent
 * new lkb's and need to receive new corresponding lkid's.
 *
 * We use the address of the rsb struct as a simple local identifier for the
 * rsb so we can match an rcom reply with the rsb it was sent for.
 */

static int recover_list_empty(struct dlm_ls *ls)
{
    int empty;

    spin_lock(&ls->ls_recover_list_lock);
    empty = list_empty(&ls->ls_recover_list);
    spin_unlock(&ls->ls_recover_list_lock);

    return empty;
}

static void recover_list_add(struct dlm_rsb *r)
{
    struct dlm_ls *ls = r->res_ls;

    spin_lock(&ls->ls_recover_list_lock);
    if (list_empty(&r->res_recover_list)) {
        list_add_tail(&r->res_recover_list, &ls->ls_recover_list);
        ls->ls_recover_list_count++;
        dlm_hold_rsb(r);
    }
    spin_unlock(&ls->ls_recover_list_lock);
}

static void recover_list_del(struct dlm_rsb *r)
{
    struct dlm_ls *ls = r->res_ls;

    spin_lock(&ls->ls_recover_list_lock);
    list_del_init(&r->res_recover_list);
    ls->ls_recover_list_count--;
    spin_unlock(&ls->ls_recover_list_lock);

    dlm_put_rsb(r);
}

static void recover_list_clear(struct dlm_ls *ls)
{
    struct dlm_rsb *r, *s;

    spin_lock(&ls->ls_recover_list_lock);
    list_for_each_entry_safe(r, s, &ls->ls_recover_list, res_recover_list) {
        list_del_init(&r->res_recover_list);
        r->res_recover_locks_count = 0;
        dlm_put_rsb(r);
        ls->ls_recover_list_count--;
    }

    if (ls->ls_recover_list_count != 0) {
        log_error(ls, "warning: recover_list_count %d",
              ls->ls_recover_list_count);
        ls->ls_recover_list_count = 0;
    }
    spin_unlock(&ls->ls_recover_list_lock);
}

static int recover_idr_empty(struct dlm_ls *ls)
{
    int empty = 1;

    spin_lock(&ls->ls_recover_idr_lock);
    if (ls->ls_recover_list_count)
        empty = 0;
    spin_unlock(&ls->ls_recover_idr_lock);

    return empty;
}

static int recover_idr_add(struct dlm_rsb *r)
{
    struct dlm_ls *ls = r->res_ls;
    int rv, id;

    rv = idr_pre_get(&ls->ls_recover_idr, GFP_NOFS);
    if (!rv)
        return -ENOMEM;

    spin_lock(&ls->ls_recover_idr_lock);
    if (r->res_id) {
        spin_unlock(&ls->ls_recover_idr_lock);
        return -1;
    }
    rv = idr_get_new_above(&ls->ls_recover_idr, r, 1, &id);
    if (rv) {
        spin_unlock(&ls->ls_recover_idr_lock);
        return rv;
    }
    r->res_id = id;
    ls->ls_recover_list_count++;
    dlm_hold_rsb(r);
    spin_unlock(&ls->ls_recover_idr_lock);
    return 0;
}

static void recover_idr_del(struct dlm_rsb *r)
{
    struct dlm_ls *ls = r->res_ls;

    spin_lock(&ls->ls_recover_idr_lock);
    idr_remove(&ls->ls_recover_idr, r->res_id);
    r->res_id = 0;
    ls->ls_recover_list_count--;
    spin_unlock(&ls->ls_recover_idr_lock);

    dlm_put_rsb(r);
}

static struct dlm_rsb *recover_idr_find(struct dlm_ls *ls, uint64_t id)
{
    struct dlm_rsb *r;

    spin_lock(&ls->ls_recover_idr_lock);
    r = idr_find(&ls->ls_recover_idr, (int)id);
    spin_unlock(&ls->ls_recover_idr_lock);
    return r;
}

static int recover_idr_clear_rsb(int id, void *p, void *data)
{
    struct dlm_ls *ls = data;
    struct dlm_rsb *r = p;

    r->res_id = 0;
    r->res_recover_locks_count = 0;
    ls->ls_recover_list_count--;

    dlm_put_rsb(r);
    return 0;
}

static void recover_idr_clear(struct dlm_ls *ls)
{
    spin_lock(&ls->ls_recover_idr_lock);
    idr_for_each(&ls->ls_recover_idr, recover_idr_clear_rsb, ls);
    idr_remove_all(&ls->ls_recover_idr);

    if (ls->ls_recover_list_count != 0) {
        log_error(ls, "warning: recover_list_count %d",
              ls->ls_recover_list_count);
        ls->ls_recover_list_count = 0;
    }
    spin_unlock(&ls->ls_recover_idr_lock);
}


/* Master recovery: find new master node for rsb's that were
   mastered on nodes that have been removed.

   dlm_recover_masters
   recover_master
   dlm_send_rcom_lookup            ->  receive_rcom_lookup
                                       dlm_dir_lookup
   receive_rcom_lookup_reply       <-
   dlm_recover_master_reply
   set_new_master
   set_master_lkbs
   set_lock_master
*/

/*
 * Set the lock master for all LKBs in a lock queue
 * If we are the new master of the rsb, we may have received new
 * MSTCPY locks from other nodes already which we need to ignore
 * when setting the new nodeid.
 */

static void set_lock_master(struct list_head *queue, int nodeid)
{
    struct dlm_lkb *lkb;

    list_for_each_entry(lkb, queue, lkb_statequeue) {
        if (!(lkb->lkb_flags & DLM_IFL_MSTCPY)) {
            lkb->lkb_nodeid = nodeid;
            lkb->lkb_remid = 0;
        }
    }
}

static void set_master_lkbs(struct dlm_rsb *r)
{
    set_lock_master(&r->res_grantqueue, r->res_nodeid);
    set_lock_master(&r->res_convertqueue, r->res_nodeid);
    set_lock_master(&r->res_waitqueue, r->res_nodeid);
}

/*
 * Propagate the new master nodeid to locks
 * The NEW_MASTER flag tells dlm_recover_locks() which rsb's to consider.
 * The NEW_MASTER2 flag tells recover_lvb() and recover_grant() which
 * rsb's to consider.
 */

static void set_new_master(struct dlm_rsb *r)
{
    set_master_lkbs(r);
    rsb_set_flag(r, RSB_NEW_MASTER);
    rsb_set_flag(r, RSB_NEW_MASTER2);
}

/*
 * We do async lookups on rsb's that need new masters.  The rsb's
 * waiting for a lookup reply are kept on the recover_list.
 *
 * Another node recovering the master may have sent us a rcom lookup,
 * and our dlm_master_lookup() set it as the new master, along with
 * NEW_MASTER so that we'll recover it here (this implies dir_nodeid
 * equals our_nodeid below).
 */

static int recover_master(struct dlm_rsb *r, unsigned int *count)
{
    struct dlm_ls *ls = r->res_ls;
    int our_nodeid, dir_nodeid;
    int is_removed = 0;
    int error;

    if (is_master(r))
        return 0;

    is_removed = dlm_is_removed(ls, r->res_nodeid);

    if (!is_removed && !rsb_flag(r, RSB_NEW_MASTER))
        return 0;

    our_nodeid = dlm_our_nodeid();
    dir_nodeid = dlm_dir_nodeid(r);

    if (dir_nodeid == our_nodeid) {
        if (is_removed) {
            r->res_master_nodeid = our_nodeid;
            r->res_nodeid = 0;
        }

        /* set master of lkbs to ourself when is_removed, or to
           another new master which we set along with NEW_MASTER
           in dlm_master_lookup */
        set_new_master(r);
        error = 0;
    } else {
        recover_idr_add(r);
        error = dlm_send_rcom_lookup(r, dir_nodeid);
    }

    (*count)++;
    return error;
}

/*
 * All MSTCPY locks are purged and rebuilt, even if the master stayed the same.
 * This is necessary because recovery can be started, aborted and restarted,
 * causing the master nodeid to briefly change during the aborted recovery, and
 * change back to the original value in the second recovery.  The MSTCPY locks
 * may or may not have been purged during the aborted recovery.  Another node
 * with an outstanding request in waiters list and a request reply saved in the
 * requestqueue, cannot know whether it should ignore the reply and resend the
 * request, or accept the reply and complete the request.  It must do the
 * former if the remote node purged MSTCPY locks, and it must do the later if
 * the remote node did not.  This is solved by always purging MSTCPY locks, in
 * which case, the request reply would always be ignored and the request
 * resent.
 */

static int recover_master_static(struct dlm_rsb *r, unsigned int *count)
{
    int dir_nodeid = dlm_dir_nodeid(r);
    int new_master = dir_nodeid;

    if (dir_nodeid == dlm_our_nodeid())
        new_master = 0;

    dlm_purge_mstcpy_locks(r);
    r->res_master_nodeid = dir_nodeid;
    r->res_nodeid = new_master;
    set_new_master(r);
    (*count)++;
    return 0;
}

/*
 * Go through local root resources and for each rsb which has a master which
 * has departed, get the new master nodeid from the directory.  The dir will
 * assign mastery to the first node to look up the new master.  That means
 * we'll discover in this lookup if we're the new master of any rsb's.
 *
 * We fire off all the dir lookup requests individually and asynchronously to
 * the correct dir node.
 */

int dlm_recover_masters(struct dlm_ls *ls)
{
    struct dlm_rsb *r;
    unsigned int total = 0;
    unsigned int count = 0;
    int nodir = dlm_no_directory(ls);
    int error;

    log_debug(ls, "dlm_recover_masters");

    down_read(&ls->ls_root_sem);
    list_for_each_entry(r, &ls->ls_root_list, res_root_list) {
        if (dlm_recovery_stopped(ls)) {
            up_read(&ls->ls_root_sem);
            error = -EINTR;
            goto out;
        }

        lock_rsb(r);
        if (nodir)
            error = recover_master_static(r, &count);
        else
            error = recover_master(r, &count);
        unlock_rsb(r);
        cond_resched();
        total++;

        if (error) {
            up_read(&ls->ls_root_sem);
            goto out;
        }
    }
    up_read(&ls->ls_root_sem);

    log_debug(ls, "dlm_recover_masters %u of %u", count, total);

    error = dlm_wait_function(ls, &recover_idr_empty);
 out:
    if (error)
        recover_idr_clear(ls);
    return error;
}

int dlm_recover_master_reply(struct dlm_ls *ls, struct dlm_rcom *rc)
{
    struct dlm_rsb *r;
    int ret_nodeid, new_master;

    r = recover_idr_find(ls, rc->rc_id);
    if (!r) {
        log_error(ls, "dlm_recover_master_reply no id %llx",
              (unsigned long long)rc->rc_id);
        goto out;
    }

    ret_nodeid = rc->rc_result;

    if (ret_nodeid == dlm_our_nodeid())
        new_master = 0;
    else
        new_master = ret_nodeid;

    lock_rsb(r);
    r->res_master_nodeid = ret_nodeid;
    r->res_nodeid = new_master;
    set_new_master(r);
    unlock_rsb(r);
    recover_idr_del(r);

    if (recover_idr_empty(ls))
        wake_up(&ls->ls_wait_general);
 out:
    return 0;
}


/* Lock recovery: rebuild the process-copy locks we hold on a
   remastered rsb on the new rsb master.

   dlm_recover_locks
   recover_locks
   recover_locks_queue
   dlm_send_rcom_lock              ->  receive_rcom_lock
                                       dlm_recover_master_copy
   receive_rcom_lock_reply         <-
   dlm_recover_process_copy
*/


/*
 * keep a count of the number of lkb's we send to the new master; when we get
 * an equal number of replies then recovery for the rsb is done
 */

static int recover_locks_queue(struct dlm_rsb *r, struct list_head *head)
{
    struct dlm_lkb *lkb;
    int error = 0;

    list_for_each_entry(lkb, head, lkb_statequeue) {
        error = dlm_send_rcom_lock(r, lkb);
        if (error)
            break;
        r->res_recover_locks_count++;
    }

    return error;
}

static int recover_locks(struct dlm_rsb *r)
{
    int error = 0;

    lock_rsb(r);

    DLM_ASSERT(!r->res_recover_locks_count, dlm_dump_rsb(r););

    error = recover_locks_queue(r, &r->res_grantqueue);
    if (error)
        goto out;
    error = recover_locks_queue(r, &r->res_convertqueue);
    if (error)
        goto out;
    error = recover_locks_queue(r, &r->res_waitqueue);
    if (error)
        goto out;

    if (r->res_recover_locks_count)
        recover_list_add(r);
    else
        rsb_clear_flag(r, RSB_NEW_MASTER);
 out:
    unlock_rsb(r);
    return error;
}

int dlm_recover_locks(struct dlm_ls *ls)
{
    struct dlm_rsb *r;
    int error, count = 0;

    down_read(&ls->ls_root_sem);
    list_for_each_entry(r, &ls->ls_root_list, res_root_list) {
        if (is_master(r)) {
            rsb_clear_flag(r, RSB_NEW_MASTER);
            continue;
        }

        if (!rsb_flag(r, RSB_NEW_MASTER))
            continue;

        if (dlm_recovery_stopped(ls)) {
            error = -EINTR;
            up_read(&ls->ls_root_sem);
            goto out;
        }

        error = recover_locks(r);
        if (error) {
            up_read(&ls->ls_root_sem);
            goto out;
        }

        count += r->res_recover_locks_count;
    }
    up_read(&ls->ls_root_sem);

    log_debug(ls, "dlm_recover_locks %d out", count);

    error = dlm_wait_function(ls, &recover_list_empty);
 out:
    if (error)
        recover_list_clear(ls);
    return error;
}

void dlm_recovered_lock(struct dlm_rsb *r)
{
    DLM_ASSERT(rsb_flag(r, RSB_NEW_MASTER), dlm_dump_rsb(r););

    r->res_recover_locks_count--;
    if (!r->res_recover_locks_count) {
        rsb_clear_flag(r, RSB_NEW_MASTER);
        recover_list_del(r);
    }

    if (recover_list_empty(r->res_ls))
        wake_up(&r->res_ls->ls_wait_general);
}

/*
 * The lvb needs to be recovered on all master rsb's.  This includes setting
 * the VALNOTVALID flag if necessary, and determining the correct lvb contents
 * based on the lvb's of the locks held on the rsb.
 *
 * RSB_VALNOTVALID is set if there are only NL/CR locks on the rsb.  If it
 * was already set prior to recovery, it's not cleared, regardless of locks.
 *
 * The LVB contents are only considered for changing when this is a new master
 * of the rsb (NEW_MASTER2).  Then, the rsb's lvb is taken from any lkb with
 * mode > CR.  If no lkb's exist with mode above CR, the lvb contents are taken
 * from the lkb with the largest lvb sequence number.
 */

static void recover_lvb(struct dlm_rsb *r)
{
    struct dlm_lkb *lkb, *high_lkb = NULL;
    uint32_t high_seq = 0;
    int lock_lvb_exists = 0;
    int big_lock_exists = 0;
    int lvblen = r->res_ls->ls_lvblen;

    list_for_each_entry(lkb, &r->res_grantqueue, lkb_statequeue) {
        if (!(lkb->lkb_exflags & DLM_LKF_VALBLK))
            continue;

        lock_lvb_exists = 1;

        if (lkb->lkb_grmode > DLM_LOCK_CR) {
            big_lock_exists = 1;
            goto setflag;
        }

        if (((int)lkb->lkb_lvbseq - (int)high_seq) >= 0) {
            high_lkb = lkb;
            high_seq = lkb->lkb_lvbseq;
        }
    }

    list_for_each_entry(lkb, &r->res_convertqueue, lkb_statequeue) {
        if (!(lkb->lkb_exflags & DLM_LKF_VALBLK))
            continue;

        lock_lvb_exists = 1;

        if (lkb->lkb_grmode > DLM_LOCK_CR) {
            big_lock_exists = 1;
            goto setflag;
        }

        if (((int)lkb->lkb_lvbseq - (int)high_seq) >= 0) {
            high_lkb = lkb;
            high_seq = lkb->lkb_lvbseq;
        }
    }

 setflag:
    if (!lock_lvb_exists)
        goto out;

    if (!big_lock_exists)
        rsb_set_flag(r, RSB_VALNOTVALID);

    /* don't mess with the lvb unless we're the new master */
    if (!rsb_flag(r, RSB_NEW_MASTER2))
        goto out;

    if (!r->res_lvbptr) {
        r->res_lvbptr = dlm_allocate_lvb(r->res_ls);
        if (!r->res_lvbptr)
            goto out;
    }

    if (big_lock_exists) {
        r->res_lvbseq = lkb->lkb_lvbseq;
        memcpy(r->res_lvbptr, lkb->lkb_lvbptr, lvblen);
    } else if (high_lkb) {
        r->res_lvbseq = high_lkb->lkb_lvbseq;
        memcpy(r->res_lvbptr, high_lkb->lkb_lvbptr, lvblen);
    } else {
        r->res_lvbseq = 0;
        memset(r->res_lvbptr, 0, lvblen);
    }
 out:
    return;
}

/* All master rsb's flagged RECOVER_CONVERT need to be looked at.  The locks
   converting PR->CW or CW->PR need to have their lkb_grmode set. */

static void recover_conversion(struct dlm_rsb *r)
{
    struct dlm_ls *ls = r->res_ls;
    struct dlm_lkb *lkb;
    int grmode = -1;

    list_for_each_entry(lkb, &r->res_grantqueue, lkb_statequeue) {
        if (lkb->lkb_grmode == DLM_LOCK_PR ||
            lkb->lkb_grmode == DLM_LOCK_CW) {
            grmode = lkb->lkb_grmode;
            break;
        }
    }

    list_for_each_entry(lkb, &r->res_convertqueue, lkb_statequeue) {
        if (lkb->lkb_grmode != DLM_LOCK_IV)
            continue;
        if (grmode == -1) {
            log_debug(ls, "recover_conversion %x set gr to rq %d",
                  lkb->lkb_id, lkb->lkb_rqmode);
            lkb->lkb_grmode = lkb->lkb_rqmode;
        } else {
            log_debug(ls, "recover_conversion %x set gr %d",
                  lkb->lkb_id, grmode);
            lkb->lkb_grmode = grmode;
        }
    }
}

/* We've become the new master for this rsb and waiting/converting locks may
   need to be granted in dlm_recover_grant() due to locks that may have
   existed from a removed node. */

static void recover_grant(struct dlm_rsb *r)
{
    if (!list_empty(&r->res_waitqueue) || !list_empty(&r->res_convertqueue))
        rsb_set_flag(r, RSB_RECOVER_GRANT);
}

void dlm_recover_rsbs(struct dlm_ls *ls)
{
    struct dlm_rsb *r;
    unsigned int count = 0;

    down_read(&ls->ls_root_sem);
    list_for_each_entry(r, &ls->ls_root_list, res_root_list) {
        lock_rsb(r);
        if (is_master(r)) {
            if (rsb_flag(r, RSB_RECOVER_CONVERT))
                recover_conversion(r);
            if (rsb_flag(r, RSB_NEW_MASTER2))
                recover_grant(r);
            recover_lvb(r);
            count++;
        }
        rsb_clear_flag(r, RSB_RECOVER_CONVERT);
        rsb_clear_flag(r, RSB_NEW_MASTER2);
        unlock_rsb(r);
    }
    up_read(&ls->ls_root_sem);

    if (count)
        log_debug(ls, "dlm_recover_rsbs %d done", count);
}

/* Create a single list of all root rsb's to be used during recovery */

int dlm_create_root_list(struct dlm_ls *ls)
{
    struct rb_node *n;
    struct dlm_rsb *r;
    int i, error = 0;

    down_write(&ls->ls_root_sem);
    if (!list_empty(&ls->ls_root_list)) {
        log_error(ls, "root list not empty");
        error = -EINVAL;
        goto out;
    }

    for (i = 0; i < ls->ls_rsbtbl_size; i++) {
        spin_lock(&ls->ls_rsbtbl[i].lock);
        for (n = rb_first(&ls->ls_rsbtbl[i].keep); n; n = rb_next(n)) {
            r = rb_entry(n, struct dlm_rsb, res_hashnode);
            list_add(&r->res_root_list, &ls->ls_root_list);
            dlm_hold_rsb(r);
        }

        if (!RB_EMPTY_ROOT(&ls->ls_rsbtbl[i].toss))
            log_error(ls, "dlm_create_root_list toss not empty");
        spin_unlock(&ls->ls_rsbtbl[i].lock);
    }
 out:
    up_write(&ls->ls_root_sem);
    return error;
}

void dlm_release_root_list(struct dlm_ls *ls)
{
    struct dlm_rsb *r, *safe;

    down_write(&ls->ls_root_sem);
    list_for_each_entry_safe(r, safe, &ls->ls_root_list, res_root_list) {
        list_del_init(&r->res_root_list);
        dlm_put_rsb(r);
    }
    up_write(&ls->ls_root_sem);
}

void dlm_clear_toss(struct dlm_ls *ls)
{
    struct rb_node *n, *next;
    struct dlm_rsb *r;
    unsigned int count = 0;
    int i;

    for (i = 0; i < ls->ls_rsbtbl_size; i++) {
        spin_lock(&ls->ls_rsbtbl[i].lock);
        for (n = rb_first(&ls->ls_rsbtbl[i].toss); n; n = next) {
            next = rb_next(n);
            r = rb_entry(n, struct dlm_rsb, res_hashnode);
            rb_erase(n, &ls->ls_rsbtbl[i].toss);
            dlm_free_rsb(r);
            count++;
        }
        spin_unlock(&ls->ls_rsbtbl[i].lock);
    }

    if (count)
        log_debug(ls, "dlm_clear_toss %u done", count);
}