/* -*- 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/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/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_entry("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_entry("%.*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_errno(tmpret);
                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;
}