dlmast.c

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/* -*- mode: c; c-basic-offset: 8; -*-
 * vim: noexpandtab sw=8 ts=8 sts=0:
 *
 * dlmast.c
 *
 * AST and BAST functionality for local and remote nodes
 *
 * 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"

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

static void dlm_update_lvb(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
               struct dlm_lock *lock);
static int dlm_should_cancel_bast(struct dlm_ctxt *dlm, struct dlm_lock *lock);

/* Should be called as an ast gets queued to see if the new
 * lock level will obsolete a pending bast.
 * For example, if dlm_thread queued a bast for an EX lock that
 * was blocking another EX, but before sending the bast the
 * lock owner downconverted to NL, the bast is now obsolete.
 * Only the ast should be sent.
 * This is needed because the lock and convert paths can queue
 * asts out-of-band (not waiting for dlm_thread) in order to
 * allow for LKM_NOQUEUE to get immediate responses. */
static int dlm_should_cancel_bast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
{
    assert_spin_locked(&dlm->ast_lock);
    assert_spin_locked(&lock->spinlock);

    if (lock->ml.highest_blocked == LKM_IVMODE)
        return 0;
    BUG_ON(lock->ml.highest_blocked == LKM_NLMODE);

    if (lock->bast_pending &&
        list_empty(&lock->bast_list))
        /* old bast already sent, ok */
        return 0;

    if (lock->ml.type == LKM_EXMODE)
        /* EX blocks anything left, any bast still valid */
        return 0;
    else if (lock->ml.type == LKM_NLMODE)
        /* NL blocks nothing, no reason to send any bast, cancel it */
        return 1;
    else if (lock->ml.highest_blocked != LKM_EXMODE)
        /* PR only blocks EX */
        return 1;

    return 0;
}

void __dlm_queue_ast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
{
    struct dlm_lock_resource *res;

    BUG_ON(!dlm);
    BUG_ON(!lock);

    res = lock->lockres;

    assert_spin_locked(&dlm->ast_lock);

    if (!list_empty(&lock->ast_list)) {
        mlog(ML_ERROR, "%s: res %.*s, lock %u:%llu, "
             "AST list not empty, pending %d, newlevel %d\n",
             dlm->name, res->lockname.len, res->lockname.name,
             dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
             dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)),
             lock->ast_pending, lock->ml.type);
        BUG();
    }
    if (lock->ast_pending)
        mlog(0, "%s: res %.*s, lock %u:%llu, AST getting flushed\n",
             dlm->name, res->lockname.len, res->lockname.name,
             dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
             dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)));

    /* putting lock on list, add a ref */
    dlm_lock_get(lock);
    spin_lock(&lock->spinlock);

    /* check to see if this ast obsoletes the bast */
    if (dlm_should_cancel_bast(dlm, lock)) {
        mlog(0, "%s: res %.*s, lock %u:%llu, Cancelling BAST\n",
             dlm->name, res->lockname.len, res->lockname.name,
             dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
             dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)));
        lock->bast_pending = 0;
        list_del_init(&lock->bast_list);
        lock->ml.highest_blocked = LKM_IVMODE;
        /* removing lock from list, remove a ref.  guaranteed
         * this won't be the last ref because of the get above,
         * so res->spinlock will not be taken here */
        dlm_lock_put(lock);
        /* free up the reserved bast that we are cancelling.
         * guaranteed that this will not be the last reserved
         * ast because *both* an ast and a bast were reserved
         * to get to this point.  the res->spinlock will not be
         * taken here */
        dlm_lockres_release_ast(dlm, res);
    }
    list_add_tail(&lock->ast_list, &dlm->pending_asts);
    lock->ast_pending = 1;
    spin_unlock(&lock->spinlock);
}

void dlm_queue_ast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
{
    BUG_ON(!dlm);
    BUG_ON(!lock);

    spin_lock(&dlm->ast_lock);
    __dlm_queue_ast(dlm, lock);
    spin_unlock(&dlm->ast_lock);
}


void __dlm_queue_bast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
{
    struct dlm_lock_resource *res;

    BUG_ON(!dlm);
    BUG_ON(!lock);

    assert_spin_locked(&dlm->ast_lock);

    res = lock->lockres;

    BUG_ON(!list_empty(&lock->bast_list));
    if (lock->bast_pending)
        mlog(0, "%s: res %.*s, lock %u:%llu, BAST getting flushed\n",
             dlm->name, res->lockname.len, res->lockname.name,
             dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
             dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)));

    /* putting lock on list, add a ref */
    dlm_lock_get(lock);
    spin_lock(&lock->spinlock);
    list_add_tail(&lock->bast_list, &dlm->pending_basts);
    lock->bast_pending = 1;
    spin_unlock(&lock->spinlock);
}

void dlm_queue_bast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
{
    BUG_ON(!dlm);
    BUG_ON(!lock);

    spin_lock(&dlm->ast_lock);
    __dlm_queue_bast(dlm, lock);
    spin_unlock(&dlm->ast_lock);
}

static void dlm_update_lvb(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
               struct dlm_lock *lock)
{
    struct dlm_lockstatus *lksb = lock->lksb;
    BUG_ON(!lksb);

    /* only updates if this node masters the lockres */
    spin_lock(&res->spinlock);
    if (res->owner == dlm->node_num) {
        /* check the lksb flags for the direction */
        if (lksb->flags & DLM_LKSB_GET_LVB) {
            mlog(0, "getting lvb from lockres for %s node\n",
                  lock->ml.node == dlm->node_num ? "master" :
                  "remote");
            memcpy(lksb->lvb, res->lvb, DLM_LVB_LEN);
        }
        /* Do nothing for lvb put requests - they should be done in
         * place when the lock is downconverted - otherwise we risk
         * racing gets and puts which could result in old lvb data
         * being propagated. We leave the put flag set and clear it
         * here. In the future we might want to clear it at the time
         * the put is actually done.
         */
    }
    spin_unlock(&res->spinlock);

    /* reset any lvb flags on the lksb */
    lksb->flags &= ~(DLM_LKSB_PUT_LVB|DLM_LKSB_GET_LVB);
}

void dlm_do_local_ast(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
              struct dlm_lock *lock)
{
    dlm_astlockfunc_t *fn;
    struct dlm_lockstatus *lksb;

    mlog(0, "%s: res %.*s, lock %u:%llu, Local AST\n", dlm->name,
         res->lockname.len, res->lockname.name,
         dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
         dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)));

    lksb = lock->lksb;
    fn = lock->ast;
    BUG_ON(lock->ml.node != dlm->node_num);

    dlm_update_lvb(dlm, res, lock);
    (*fn)(lock->astdata);
}


int dlm_do_remote_ast(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
              struct dlm_lock *lock)
{
    int ret;
    struct dlm_lockstatus *lksb;
    int lksbflags;

    mlog(0, "%s: res %.*s, lock %u:%llu, Remote AST\n", dlm->name,
         res->lockname.len, res->lockname.name,
         dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
         dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)));

    lksb = lock->lksb;
    BUG_ON(lock->ml.node == dlm->node_num);

    lksbflags = lksb->flags;
    dlm_update_lvb(dlm, res, lock);

    /* lock request came from another node
     * go do the ast over there */
    ret = dlm_send_proxy_ast(dlm, res, lock, lksbflags);
    return ret;
}

void dlm_do_local_bast(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
               struct dlm_lock *lock, int blocked_type)
{
    dlm_bastlockfunc_t *fn = lock->bast;

    BUG_ON(lock->ml.node != dlm->node_num);

    mlog(0, "%s: res %.*s, lock %u:%llu, Local BAST, blocked %d\n",
         dlm->name, res->lockname.len, res->lockname.name,
         dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
         dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)),
         blocked_type);

    (*fn)(lock->astdata, blocked_type);
}



int dlm_proxy_ast_handler(struct o2net_msg *msg, u32 len, void *data,
              void **ret_data)
{
    int ret;
    unsigned int locklen;
    struct dlm_ctxt *dlm = data;
    struct dlm_lock_resource *res = NULL;
    struct dlm_lock *lock = NULL;
    struct dlm_proxy_ast *past = (struct dlm_proxy_ast *) msg->buf;
    char *name;
    struct list_head *iter, *head=NULL;
    __be64 cookie;
    u32 flags;
    u8 node;

    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);

    name = past->name;
    locklen = past->namelen;
    cookie = past->cookie;
    flags = be32_to_cpu(past->flags);
    node = past->node_idx;

    if (locklen > DLM_LOCKID_NAME_MAX) {
        ret = DLM_IVBUFLEN;
        mlog(ML_ERROR, "Invalid name length (%d) in proxy ast "
             "handler!\n", locklen);
        goto leave;
    }

    if ((flags & (LKM_PUT_LVB|LKM_GET_LVB)) ==
         (LKM_PUT_LVB|LKM_GET_LVB)) {
        mlog(ML_ERROR, "Both PUT and GET lvb specified, (0x%x)\n",
             flags);
        ret = DLM_BADARGS;
        goto leave;
    }

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

    mlog(0, "type=%d, blocked_type=%d\n", past->type, past->blocked_type);

    if (past->type != DLM_AST &&
        past->type != DLM_BAST) {
        mlog(ML_ERROR, "Unknown ast type! %d, cookie=%u:%llu"
             "name=%.*s, node=%u\n", past->type,
             dlm_get_lock_cookie_node(be64_to_cpu(cookie)),
             dlm_get_lock_cookie_seq(be64_to_cpu(cookie)),
             locklen, name, node);
        ret = DLM_IVLOCKID;
        goto leave;
    }

    res = dlm_lookup_lockres(dlm, name, locklen);
    if (!res) {
        mlog(0, "Got %sast for unknown lockres! cookie=%u:%llu, "
             "name=%.*s, node=%u\n", (past->type == DLM_AST ? "" : "b"),
             dlm_get_lock_cookie_node(be64_to_cpu(cookie)),
             dlm_get_lock_cookie_seq(be64_to_cpu(cookie)),
             locklen, name, node);
        ret = DLM_IVLOCKID;
        goto leave;
    }

    /* cannot get a proxy ast message if this node owns it */
    BUG_ON(res->owner == dlm->node_num);

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

    spin_lock(&res->spinlock);
    if (res->state & DLM_LOCK_RES_RECOVERING) {
        mlog(0, "Responding with DLM_RECOVERING!\n");
        ret = DLM_RECOVERING;
        goto unlock_out;
    }
    if (res->state & DLM_LOCK_RES_MIGRATING) {
        mlog(0, "Responding with DLM_MIGRATING!\n");
        ret = DLM_MIGRATING;
        goto unlock_out;
    }
    /* try convert queue for both ast/bast */
    head = &res->converting;
    lock = NULL;
    list_for_each(iter, head) {
        lock = list_entry (iter, struct dlm_lock, list);
        if (lock->ml.cookie == cookie)
            goto do_ast;
    }

    /* if not on convert, try blocked for ast, granted for bast */
    if (past->type == DLM_AST)
        head = &res->blocked;
    else
        head = &res->granted;

    list_for_each(iter, head) {
        lock = list_entry (iter, struct dlm_lock, list);
        if (lock->ml.cookie == cookie)
            goto do_ast;
    }

    mlog(0, "Got %sast for unknown lock! cookie=%u:%llu, name=%.*s, "
         "node=%u\n", past->type == DLM_AST ? "" : "b",
         dlm_get_lock_cookie_node(be64_to_cpu(cookie)),
         dlm_get_lock_cookie_seq(be64_to_cpu(cookie)),
         locklen, name, node);

    ret = DLM_NORMAL;
unlock_out:
    spin_unlock(&res->spinlock);
    goto leave;

do_ast:
    ret = DLM_NORMAL;
    if (past->type == DLM_AST) {
        /* do not alter lock refcount.  switching lists. */
        list_move_tail(&lock->list, &res->granted);
        mlog(0, "%s: res %.*s, lock %u:%llu, Granted type %d => %d\n",
             dlm->name, res->lockname.len, res->lockname.name,
             dlm_get_lock_cookie_node(be64_to_cpu(cookie)),
             dlm_get_lock_cookie_seq(be64_to_cpu(cookie)),
             lock->ml.type, lock->ml.convert_type);

        if (lock->ml.convert_type != LKM_IVMODE) {
            lock->ml.type = lock->ml.convert_type;
            lock->ml.convert_type = LKM_IVMODE;
        } else {
            // should already be there....
        }

        lock->lksb->status = DLM_NORMAL;

        /* if we requested the lvb, fetch it into our lksb now */
        if (flags & LKM_GET_LVB) {
            BUG_ON(!(lock->lksb->flags & DLM_LKSB_GET_LVB));
            memcpy(lock->lksb->lvb, past->lvb, DLM_LVB_LEN);
        }
    }
    spin_unlock(&res->spinlock);

    if (past->type == DLM_AST)
        dlm_do_local_ast(dlm, res, lock);
    else
        dlm_do_local_bast(dlm, res, lock, past->blocked_type);

leave:
    if (res)
        dlm_lockres_put(res);

    dlm_put(dlm);
    return ret;
}



int dlm_send_proxy_ast_msg(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
               struct dlm_lock *lock, int msg_type,
               int blocked_type, int flags)
{
    int ret = 0;
    struct dlm_proxy_ast past;
    struct kvec vec[2];
    size_t veclen = 1;
    int status;

    mlog(0, "%s: res %.*s, to %u, type %d, blocked_type %d\n", dlm->name,
         res->lockname.len, res->lockname.name, lock->ml.node, msg_type,
         blocked_type);

    memset(&past, 0, sizeof(struct dlm_proxy_ast));
    past.node_idx = dlm->node_num;
    past.type = msg_type;
    past.blocked_type = blocked_type;
    past.namelen = res->lockname.len;
    memcpy(past.name, res->lockname.name, past.namelen);
    past.cookie = lock->ml.cookie;

    vec[0].iov_len = sizeof(struct dlm_proxy_ast);
    vec[0].iov_base = &past;
    if (flags & DLM_LKSB_GET_LVB) {
        be32_add_cpu(&past.flags, LKM_GET_LVB);
        vec[1].iov_len = DLM_LVB_LEN;
        vec[1].iov_base = lock->lksb->lvb;
        veclen++;
    }

    ret = o2net_send_message_vec(DLM_PROXY_AST_MSG, dlm->key, vec, veclen,
                     lock->ml.node, &status);
    if (ret < 0)
        mlog(ML_ERROR, "%s: res %.*s, error %d send AST to node %u\n",
             dlm->name, res->lockname.len, res->lockname.name, ret,
             lock->ml.node);
    else {
        if (status == DLM_RECOVERING) {
            mlog(ML_ERROR, "sent AST to node %u, it thinks this "
                 "node is dead!\n", lock->ml.node);
            BUG();
        } else if (status == DLM_MIGRATING) {
            mlog(ML_ERROR, "sent AST to node %u, it returned "
                 "DLM_MIGRATING!\n", lock->ml.node);
            BUG();
        } else if (status != DLM_NORMAL && status != DLM_IVLOCKID) {
            mlog(ML_ERROR, "AST to node %u returned %d!\n",
                 lock->ml.node, status);
            /* ignore it */
        }
        ret = 0;
    }
    return ret;
}