dlmconvert.c

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/* -*- mode: c; c-basic-offset: 8; -*-
 * vim: noexpandtab sw=8 ts=8 sts=0:
 *
 * dlmconvert.c
 *
 * underlying calls for lock conversion
 *
 * 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/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/spinlock.h>


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

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

#include "dlmconvert.h"

#define MLOG_MASK_PREFIX ML_DLM
#include "cluster/masklog.h"

/* NOTE: __dlmconvert_master is the only function in here that
 * needs a spinlock held on entry (res->spinlock) and it is the
 * only one that holds a lock on exit (res->spinlock).
 * All other functions in here need no locks and drop all of
 * the locks that they acquire. */
static enum dlm_status __dlmconvert_master(struct dlm_ctxt *dlm,
                       struct dlm_lock_resource *res,
                       struct dlm_lock *lock, int flags,
                       int type, int *call_ast,
                       int *kick_thread);
static enum dlm_status dlm_send_remote_convert_request(struct dlm_ctxt *dlm,
                       struct dlm_lock_resource *res,
                       struct dlm_lock *lock, int flags, int type);

/*
 * this is only called directly by dlmlock(), and only when the
 * local node is the owner of the lockres
 * locking:
 *   caller needs:  none
 *   taken:         takes and drops res->spinlock
 *   held on exit:  none
 * returns: see __dlmconvert_master
 */
enum dlm_status dlmconvert_master(struct dlm_ctxt *dlm,
                  struct dlm_lock_resource *res,
                  struct dlm_lock *lock, int flags, int type)
{
    int call_ast = 0, kick_thread = 0;
    enum dlm_status status;

    spin_lock(&res->spinlock);
    /* we are not in a network handler, this is fine */
    __dlm_wait_on_lockres(res);
    __dlm_lockres_reserve_ast(res);
    res->state |= DLM_LOCK_RES_IN_PROGRESS;

    status = __dlmconvert_master(dlm, res, lock, flags, type,
                     &call_ast, &kick_thread);

    res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
    spin_unlock(&res->spinlock);
    wake_up(&res->wq);
    if (status != DLM_NORMAL && status != DLM_NOTQUEUED)
        dlm_error(status);

    /* either queue the ast or release it */
    if (call_ast)
        dlm_queue_ast(dlm, lock);
    else
        dlm_lockres_release_ast(dlm, res);

    if (kick_thread)
        dlm_kick_thread(dlm, res);

    return status;
}

/* performs lock conversion at the lockres master site
 * locking:
 *   caller needs:  res->spinlock
 *   taken:         takes and drops lock->spinlock
 *   held on exit:  res->spinlock
 * returns: DLM_NORMAL, DLM_NOTQUEUED, DLM_DENIED
 *   call_ast: whether ast should be called for this lock
 *   kick_thread: whether dlm_kick_thread should be called
 */
static enum dlm_status __dlmconvert_master(struct dlm_ctxt *dlm,
                       struct dlm_lock_resource *res,
                       struct dlm_lock *lock, int flags,
                       int type, int *call_ast,
                       int *kick_thread)
{
    enum dlm_status status = DLM_NORMAL;
    struct list_head *iter;
    struct dlm_lock *tmplock=NULL;

    assert_spin_locked(&res->spinlock);

    mlog(0, "type=%d, convert_type=%d, new convert_type=%d\n",
         lock->ml.type, lock->ml.convert_type, type);

    spin_lock(&lock->spinlock);

    /* already converting? */
    if (lock->ml.convert_type != LKM_IVMODE) {
        mlog(ML_ERROR, "attempted to convert a lock with a lock "
             "conversion pending\n");
        status = DLM_DENIED;
        goto unlock_exit;
    }

    /* must be on grant queue to convert */
    if (!dlm_lock_on_list(&res->granted, lock)) {
        mlog(ML_ERROR, "attempted to convert a lock not on grant "
             "queue\n");
        status = DLM_DENIED;
        goto unlock_exit;
    }

    if (flags & LKM_VALBLK) {
        switch (lock->ml.type) {
            case LKM_EXMODE:
                /* EX + LKM_VALBLK + convert == set lvb */
                mlog(0, "will set lvb: converting %s->%s\n",
                     dlm_lock_mode_name(lock->ml.type),
                     dlm_lock_mode_name(type));
                lock->lksb->flags |= DLM_LKSB_PUT_LVB;
                break;
            case LKM_PRMODE:
            case LKM_NLMODE:
                /* refetch if new level is not NL */
                if (type > LKM_NLMODE) {
                    mlog(0, "will fetch new value into "
                         "lvb: converting %s->%s\n",
                         dlm_lock_mode_name(lock->ml.type),
                         dlm_lock_mode_name(type));
                    lock->lksb->flags |= DLM_LKSB_GET_LVB;
                } else {
                    mlog(0, "will NOT fetch new value "
                         "into lvb: converting %s->%s\n",
                         dlm_lock_mode_name(lock->ml.type),
                         dlm_lock_mode_name(type));
                    flags &= ~(LKM_VALBLK);
                }
                break;
        }
    }


    /* in-place downconvert? */
    if (type <= lock->ml.type)
        goto grant;

    /* upconvert from here on */
    status = DLM_NORMAL;
    list_for_each(iter, &res->granted) {
        tmplock = list_entry(iter, struct dlm_lock, list);
        if (tmplock == lock)
            continue;
        if (!dlm_lock_compatible(tmplock->ml.type, type))
            goto switch_queues;
    }

    list_for_each(iter, &res->converting) {
        tmplock = list_entry(iter, struct dlm_lock, list);
        if (!dlm_lock_compatible(tmplock->ml.type, type))
            goto switch_queues;
        /* existing conversion requests take precedence */
        if (!dlm_lock_compatible(tmplock->ml.convert_type, type))
            goto switch_queues;
    }

    /* fall thru to grant */

grant:
    mlog(0, "res %.*s, granting %s lock\n", res->lockname.len,
         res->lockname.name, dlm_lock_mode_name(type));
    /* immediately grant the new lock type */
    lock->lksb->status = DLM_NORMAL;
    if (lock->ml.node == dlm->node_num)
        mlog(0, "doing in-place convert for nonlocal lock\n");
    lock->ml.type = type;
    if (lock->lksb->flags & DLM_LKSB_PUT_LVB)
        memcpy(res->lvb, lock->lksb->lvb, DLM_LVB_LEN);

    status = DLM_NORMAL;
    *call_ast = 1;
    goto unlock_exit;

switch_queues:
    if (flags & LKM_NOQUEUE) {
        mlog(0, "failed to convert NOQUEUE lock %.*s from "
             "%d to %d...\n", res->lockname.len, res->lockname.name,
             lock->ml.type, type);
        status = DLM_NOTQUEUED;
        goto unlock_exit;
    }
    mlog(0, "res %.*s, queueing...\n", res->lockname.len,
         res->lockname.name);

    lock->ml.convert_type = type;
    /* do not alter lock refcount.  switching lists. */
    list_move_tail(&lock->list, &res->converting);

unlock_exit:
    spin_unlock(&lock->spinlock);
    if (status == DLM_DENIED) {
        __dlm_print_one_lock_resource(res);
    }
    if (status == DLM_NORMAL)
        *kick_thread = 1;
    return status;
}

void dlm_revert_pending_convert(struct dlm_lock_resource *res,
                struct dlm_lock *lock)
{
    /* do not alter lock refcount.  switching lists. */
    list_move_tail(&lock->list, &res->granted);
    lock->ml.convert_type = LKM_IVMODE;
    lock->lksb->flags &= ~(DLM_LKSB_GET_LVB|DLM_LKSB_PUT_LVB);
}

/* messages the master site to do lock conversion
 * locking:
 *   caller needs:  none
 *   taken:         takes and drops res->spinlock, uses DLM_LOCK_RES_IN_PROGRESS
 *   held on exit:  none
 * returns: DLM_NORMAL, DLM_RECOVERING, status from remote node
 */
enum dlm_status dlmconvert_remote(struct dlm_ctxt *dlm,
                  struct dlm_lock_resource *res,
                  struct dlm_lock *lock, int flags, int type)
{
    enum dlm_status status;

    mlog(0, "type=%d, convert_type=%d, busy=%d\n", lock->ml.type,
         lock->ml.convert_type, res->state & DLM_LOCK_RES_IN_PROGRESS);

    spin_lock(&res->spinlock);
    if (res->state & DLM_LOCK_RES_RECOVERING) {
        mlog(0, "bailing out early since res is RECOVERING "
             "on secondary queue\n");
        /* __dlm_print_one_lock_resource(res); */
        status = DLM_RECOVERING;
        goto bail;
    }
    /* will exit this call with spinlock held */
    __dlm_wait_on_lockres(res);

    if (lock->ml.convert_type != LKM_IVMODE) {
        __dlm_print_one_lock_resource(res);
        mlog(ML_ERROR, "converting a remote lock that is already "
             "converting! (cookie=%u:%llu, conv=%d)\n",
             dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
             dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)),
             lock->ml.convert_type);
        status = DLM_DENIED;
        goto bail;
    }
    res->state |= DLM_LOCK_RES_IN_PROGRESS;
    /* move lock to local convert queue */
    /* do not alter lock refcount.  switching lists. */
    list_move_tail(&lock->list, &res->converting);
    lock->convert_pending = 1;
    lock->ml.convert_type = type;

    if (flags & LKM_VALBLK) {
        if (lock->ml.type == LKM_EXMODE) {
            flags |= LKM_PUT_LVB;
            lock->lksb->flags |= DLM_LKSB_PUT_LVB;
        } else {
            if (lock->ml.convert_type == LKM_NLMODE)
                flags &= ~LKM_VALBLK;
            else {
                flags |= LKM_GET_LVB;
                lock->lksb->flags |= DLM_LKSB_GET_LVB;
            }
        }
    }
    spin_unlock(&res->spinlock);

    /* no locks held here.
     * need to wait for a reply as to whether it got queued or not. */
    status = dlm_send_remote_convert_request(dlm, res, lock, flags, type);

    spin_lock(&res->spinlock);
    res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
    lock->convert_pending = 0;
    /* if it failed, move it back to granted queue */
    if (status != DLM_NORMAL) {
        if (status != DLM_NOTQUEUED)
            dlm_error(status);
        dlm_revert_pending_convert(res, lock);
    }
bail:
    spin_unlock(&res->spinlock);

    /* TODO: should this be a wake_one? */
    /* wake up any IN_PROGRESS waiters */
    wake_up(&res->wq);

    return status;
}

/* sends DLM_CONVERT_LOCK_MSG to master site
 * locking:
 *   caller needs:  none
 *   taken:         none
 *   held on exit:  none
 * returns: DLM_NOLOCKMGR, status from remote node
 */
static enum dlm_status dlm_send_remote_convert_request(struct dlm_ctxt *dlm,
                       struct dlm_lock_resource *res,
                       struct dlm_lock *lock, int flags, int type)
{
    struct dlm_convert_lock convert;
    int tmpret;
    enum dlm_status ret;
    int status = 0;
    struct kvec vec[2];
    size_t veclen = 1;

    mlog(0, "%.*s\n", res->lockname.len, res->lockname.name);

    memset(&convert, 0, sizeof(struct dlm_convert_lock));
    convert.node_idx = dlm->node_num;
    convert.requested_type = type;
    convert.cookie = lock->ml.cookie;
    convert.namelen = res->lockname.len;
    convert.flags = cpu_to_be32(flags);
    memcpy(convert.name, res->lockname.name, convert.namelen);

    vec[0].iov_len = sizeof(struct dlm_convert_lock);
    vec[0].iov_base = &convert;

    if (flags & LKM_PUT_LVB) {
        /* extra data to send if we are updating lvb */
        vec[1].iov_len = DLM_LVB_LEN;
        vec[1].iov_base = lock->lksb->lvb;
        veclen++;
    }

    tmpret = o2net_send_message_vec(DLM_CONVERT_LOCK_MSG, dlm->key,
                    vec, veclen, res->owner, &status);
    if (tmpret >= 0) {
        // successfully sent and received
        ret = status;  // this is already a dlm_status
        if (ret == DLM_RECOVERING) {
            mlog(0, "node %u returned DLM_RECOVERING from convert "
                 "message!\n", res->owner);
        } else if (ret == DLM_MIGRATING) {
            mlog(0, "node %u returned DLM_MIGRATING from convert "
                 "message!\n", res->owner);
        } else if (ret == DLM_FORWARD) {
            mlog(0, "node %u returned DLM_FORWARD from convert "
                 "message!\n", res->owner);
        } else if (ret != DLM_NORMAL && ret != DLM_NOTQUEUED)
            dlm_error(ret);
    } else {
        mlog(ML_ERROR, "Error %d when sending message %u (key 0x%x) to "
             "node %u\n", tmpret, DLM_CONVERT_LOCK_MSG, dlm->key,
             res->owner);
        if (dlm_is_host_down(tmpret)) {
            /* instead of logging the same network error over
             * and over, sleep here and wait for the heartbeat
             * to notice the node is dead.  times out after 5s. */
            dlm_wait_for_node_death(dlm, res->owner,
                        DLM_NODE_DEATH_WAIT_MAX);
            ret = DLM_RECOVERING;
            mlog(0, "node %u died so returning DLM_RECOVERING "
                 "from convert message!\n", res->owner);
        } else {
            ret = dlm_err_to_dlm_status(tmpret);
        }
    }

    return ret;
}

/* handler for DLM_CONVERT_LOCK_MSG on master site
 * locking:
 *   caller needs:  none
 *   taken:         takes and drop res->spinlock
 *   held on exit:  none
 * returns: DLM_NORMAL, DLM_IVLOCKID, DLM_BADARGS,
 *          status from __dlmconvert_master
 */
int dlm_convert_lock_handler(struct o2net_msg *msg, u32 len, void *data,
                 void **ret_data)
{
    struct dlm_ctxt *dlm = data;
    struct dlm_convert_lock *cnv = (struct dlm_convert_lock *)msg->buf;
    struct dlm_lock_resource *res = NULL;
    struct list_head *iter;
    struct dlm_lock *lock = NULL;
    struct dlm_lockstatus *lksb;
    enum dlm_status status = DLM_NORMAL;
    u32 flags;
    int call_ast = 0, kick_thread = 0, ast_reserved = 0, wake = 0;

    if (!dlm_grab(dlm)) {
        dlm_error(DLM_REJECTED);
        return DLM_REJECTED;
    }

    mlog_bug_on_msg(!dlm_domain_fully_joined(dlm),
            "Domain %s not fully joined!\n", dlm->name);

    if (cnv->namelen > DLM_LOCKID_NAME_MAX) {
        status = DLM_IVBUFLEN;
        dlm_error(status);
        goto leave;
    }

    flags = be32_to_cpu(cnv->flags);

    if ((flags & (LKM_PUT_LVB|LKM_GET_LVB)) ==
         (LKM_PUT_LVB|LKM_GET_LVB)) {
        mlog(ML_ERROR, "both PUT and GET lvb specified\n");
        status = DLM_BADARGS;
        goto leave;
    }

    mlog(0, "lvb: %s\n", flags & LKM_PUT_LVB ? "put lvb" :
         (flags & LKM_GET_LVB ? "get lvb" : "none"));

    status = DLM_IVLOCKID;
    res = dlm_lookup_lockres(dlm, cnv->name, cnv->namelen);
    if (!res) {
        dlm_error(status);
        goto leave;
    }

    spin_lock(&res->spinlock);
    status = __dlm_lockres_state_to_status(res);
    if (status != DLM_NORMAL) {
        spin_unlock(&res->spinlock);
        dlm_error(status);
        goto leave;
    }
    list_for_each(iter, &res->granted) {
        lock = list_entry(iter, struct dlm_lock, list);
        if (lock->ml.cookie == cnv->cookie &&
            lock->ml.node == cnv->node_idx) {
            dlm_lock_get(lock);
            break;
        }
        lock = NULL;
    }
    spin_unlock(&res->spinlock);
    if (!lock) {
        status = DLM_IVLOCKID;
        mlog(ML_ERROR, "did not find lock to convert on grant queue! "
                   "cookie=%u:%llu\n",
             dlm_get_lock_cookie_node(be64_to_cpu(cnv->cookie)),
             dlm_get_lock_cookie_seq(be64_to_cpu(cnv->cookie)));
        dlm_print_one_lock_resource(res);
        goto leave;
    }

    /* found the lock */
    lksb = lock->lksb;

    /* see if caller needed to get/put lvb */
    if (flags & LKM_PUT_LVB) {
        BUG_ON(lksb->flags & (DLM_LKSB_PUT_LVB|DLM_LKSB_GET_LVB));
        lksb->flags |= DLM_LKSB_PUT_LVB;
        memcpy(&lksb->lvb[0], &cnv->lvb[0], DLM_LVB_LEN);
    } else if (flags & LKM_GET_LVB) {
        BUG_ON(lksb->flags & (DLM_LKSB_PUT_LVB|DLM_LKSB_GET_LVB));
        lksb->flags |= DLM_LKSB_GET_LVB;
    }

    spin_lock(&res->spinlock);
    status = __dlm_lockres_state_to_status(res);
    if (status == DLM_NORMAL) {
        __dlm_lockres_reserve_ast(res);
        ast_reserved = 1;
        res->state |= DLM_LOCK_RES_IN_PROGRESS;
        status = __dlmconvert_master(dlm, res, lock, flags,
                         cnv->requested_type,
                         &call_ast, &kick_thread);
        res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
        wake = 1;
    }
    spin_unlock(&res->spinlock);
    if (wake)
        wake_up(&res->wq);

    if (status != DLM_NORMAL) {
        if (status != DLM_NOTQUEUED)
            dlm_error(status);
        lksb->flags &= ~(DLM_LKSB_GET_LVB|DLM_LKSB_PUT_LVB);
    }

leave:
    if (lock)
        dlm_lock_put(lock);

    /* either queue the ast or release it, if reserved */
    if (call_ast)
        dlm_queue_ast(dlm, lock);
    else if (ast_reserved)
        dlm_lockres_release_ast(dlm, res);

    if (kick_thread)
        dlm_kick_thread(dlm, res);

    if (res)
        dlm_lockres_put(res);

    dlm_put(dlm);

    return status;
}