/******************************************************************************
*******************************************************************************
**
**  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
**  Copyright (C) 2005-2008 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 "member.h"
#include "lowcomms.h"
#include "midcomms.h"
#include "rcom.h"
#include "recover.h"
#include "dir.h"
#include "config.h"
#include "memory.h"
#include "lock.h"
#include "util.h"

static int rcom_response(struct dlm_ls *ls)
{
        return test_bit(LSFL_RCOM_READY, &ls->ls_flags);
}

static int create_rcom(struct dlm_ls *ls, int to_nodeid, int type, int len,
                       struct dlm_rcom **rc_ret, struct dlm_mhandle **mh_ret)
{
        struct dlm_rcom *rc;
        struct dlm_mhandle *mh;
        char *mb;
        int mb_len = sizeof(struct dlm_rcom) + len;

        mh = dlm_lowcomms_get_buffer(to_nodeid, mb_len, GFP_NOFS, &mb);
        if (!mh) {
                log_print("create_rcom to %d type %d len %d ENOBUFS",
                          to_nodeid, type, len);
                return -ENOBUFS;
        }
        memset(mb, 0, mb_len);

        rc = (struct dlm_rcom *) mb;

        rc->rc_header.h_version = (DLM_HEADER_MAJOR | DLM_HEADER_MINOR);
        rc->rc_header.h_lockspace = ls->ls_global_id;
        rc->rc_header.h_nodeid = dlm_our_nodeid();
        rc->rc_header.h_length = mb_len;
        rc->rc_header.h_cmd = DLM_RCOM;

        rc->rc_type = type;

        spin_lock(&ls->ls_recover_lock);
        rc->rc_seq = ls->ls_recover_seq;
        spin_unlock(&ls->ls_recover_lock);

        *mh_ret = mh;
        *rc_ret = rc;
        return 0;
}

static void send_rcom(struct dlm_ls *ls, struct dlm_mhandle *mh,
                      struct dlm_rcom *rc)
{
        dlm_rcom_out(rc);
        dlm_lowcomms_commit_buffer(mh);
}

static void set_rcom_status(struct dlm_ls *ls, struct rcom_status *rs,
                            uint32_t flags)
{
        rs->rs_flags = cpu_to_le32(flags);
}

/* When replying to a status request, a node also sends back its
   configuration values.  The requesting node then checks that the remote
   node is configured the same way as itself. */

static void set_rcom_config(struct dlm_ls *ls, struct rcom_config *rf,
                            uint32_t num_slots)
{
        rf->rf_lvblen = cpu_to_le32(ls->ls_lvblen);
        rf->rf_lsflags = cpu_to_le32(ls->ls_exflags);

        rf->rf_our_slot = cpu_to_le16(ls->ls_slot);
        rf->rf_num_slots = cpu_to_le16(num_slots);
        rf->rf_generation =  cpu_to_le32(ls->ls_generation);
}

static int check_rcom_config(struct dlm_ls *ls, struct dlm_rcom *rc, int nodeid)
{
        struct rcom_config *rf = (struct rcom_config *) rc->rc_buf;

        if ((rc->rc_header.h_version & 0xFFFF0000) != DLM_HEADER_MAJOR) {
                log_error(ls, "version mismatch: %x nodeid %d: %x",
                          DLM_HEADER_MAJOR | DLM_HEADER_MINOR, nodeid,
                          rc->rc_header.h_version);
                return -EPROTO;
        }

        if (le32_to_cpu(rf->rf_lvblen) != ls->ls_lvblen ||
            le32_to_cpu(rf->rf_lsflags) != ls->ls_exflags) {
                log_error(ls, "config mismatch: %d,%x nodeid %d: %d,%x",
                          ls->ls_lvblen, ls->ls_exflags, nodeid,
                          le32_to_cpu(rf->rf_lvblen),
                          le32_to_cpu(rf->rf_lsflags));
                return -EPROTO;
        }
        return 0;
}

static void allow_sync_reply(struct dlm_ls *ls, uint64_t *new_seq)
{
        spin_lock(&ls->ls_rcom_spin);
        *new_seq = ++ls->ls_rcom_seq;
        set_bit(LSFL_RCOM_WAIT, &ls->ls_flags);
        spin_unlock(&ls->ls_rcom_spin);
}

static void disallow_sync_reply(struct dlm_ls *ls)
{
        spin_lock(&ls->ls_rcom_spin);
        clear_bit(LSFL_RCOM_WAIT, &ls->ls_flags);
        clear_bit(LSFL_RCOM_READY, &ls->ls_flags);
        spin_unlock(&ls->ls_rcom_spin);
}

/*
 * low nodeid gathers one slot value at a time from each node.
 * it sets need_slots=0, and saves rf_our_slot returned from each
 * rcom_config.
 *
 * other nodes gather all slot values at once from the low nodeid.
 * they set need_slots=1, and ignore the rf_our_slot returned from each
 * rcom_config.  they use the rf_num_slots returned from the low
 * node's rcom_config.
 */

int dlm_rcom_status(struct dlm_ls *ls, int nodeid, uint32_t status_flags)
{
        struct dlm_rcom *rc;
        struct dlm_mhandle *mh;
        int error = 0;

        ls->ls_recover_nodeid = nodeid;

        if (nodeid == dlm_our_nodeid()) {
                rc = ls->ls_recover_buf;
                rc->rc_result = dlm_recover_status(ls);
                goto out;
        }

        error = create_rcom(ls, nodeid, DLM_RCOM_STATUS,
                            sizeof(struct rcom_status), &rc, &mh);
        if (error)
                goto out;

        set_rcom_status(ls, (struct rcom_status *)rc->rc_buf, status_flags);

        allow_sync_reply(ls, &rc->rc_id);
        memset(ls->ls_recover_buf, 0, dlm_config.ci_buffer_size);

        send_rcom(ls, mh, rc);

        error = dlm_wait_function(ls, &rcom_response);
        disallow_sync_reply(ls);
        if (error)
                goto out;

        rc = ls->ls_recover_buf;

        if (rc->rc_result == -ESRCH) {
                /* we pretend the remote lockspace exists with 0 status */
                log_debug(ls, "remote node %d not ready", nodeid);
                rc->rc_result = 0;
                error = 0;
        } else {
                error = check_rcom_config(ls, rc, nodeid);
        }

        /* the caller looks at rc_result for the remote recovery status */
 out:
        return error;
}

static void receive_rcom_status(struct dlm_ls *ls, struct dlm_rcom *rc_in)
{
        struct dlm_rcom *rc;
        struct dlm_mhandle *mh;
        struct rcom_status *rs;
        uint32_t status;
        int nodeid = rc_in->rc_header.h_nodeid;
        int len = sizeof(struct rcom_config);
        int num_slots = 0;
        int error;

        if (!dlm_slots_version(&rc_in->rc_header)) {
                status = dlm_recover_status(ls);
                goto do_create;
        }

        rs = (struct rcom_status *)rc_in->rc_buf;

        if (!(rs->rs_flags & DLM_RSF_NEED_SLOTS)) {
                status = dlm_recover_status(ls);
                goto do_create;
        }

        spin_lock(&ls->ls_recover_lock);
        status = ls->ls_recover_status;
        num_slots = ls->ls_num_slots;
        spin_unlock(&ls->ls_recover_lock);
        len += num_slots * sizeof(struct rcom_slot);

 do_create:
        error = create_rcom(ls, nodeid, DLM_RCOM_STATUS_REPLY,
                            len, &rc, &mh);
        if (error)
                return;

        rc->rc_id = rc_in->rc_id;
        rc->rc_seq_reply = rc_in->rc_seq;
        rc->rc_result = status;

        set_rcom_config(ls, (struct rcom_config *)rc->rc_buf, num_slots);

        if (!num_slots)
                goto do_send;

        spin_lock(&ls->ls_recover_lock);
        if (ls->ls_num_slots != num_slots) {
                spin_unlock(&ls->ls_recover_lock);
                log_debug(ls, "receive_rcom_status num_slots %d to %d",
                          num_slots, ls->ls_num_slots);
                rc->rc_result = 0;
                set_rcom_config(ls, (struct rcom_config *)rc->rc_buf, 0);
                goto do_send;
        }

        dlm_slots_copy_out(ls, rc);
        spin_unlock(&ls->ls_recover_lock);

 do_send:
        send_rcom(ls, mh, rc);
}

static void receive_sync_reply(struct dlm_ls *ls, struct dlm_rcom *rc_in)
{
        spin_lock(&ls->ls_rcom_spin);
        if (!test_bit(LSFL_RCOM_WAIT, &ls->ls_flags) ||
            rc_in->rc_id != ls->ls_rcom_seq) {
                log_debug(ls, "reject reply %d from %d seq %llx expect %llx",
                          rc_in->rc_type, rc_in->rc_header.h_nodeid,
                          (unsigned long long)rc_in->rc_id,
                          (unsigned long long)ls->ls_rcom_seq);
                goto out;
        }
        memcpy(ls->ls_recover_buf, rc_in, rc_in->rc_header.h_length);
        set_bit(LSFL_RCOM_READY, &ls->ls_flags);
        clear_bit(LSFL_RCOM_WAIT, &ls->ls_flags);
        wake_up(&ls->ls_wait_general);
 out:
        spin_unlock(&ls->ls_rcom_spin);
}

int dlm_rcom_names(struct dlm_ls *ls, int nodeid, char *last_name, int last_len)
{
        struct dlm_rcom *rc;
        struct dlm_mhandle *mh;
        int error = 0;

        ls->ls_recover_nodeid = nodeid;

        error = create_rcom(ls, nodeid, DLM_RCOM_NAMES, last_len, &rc, &mh);
        if (error)
                goto out;
        memcpy(rc->rc_buf, last_name, last_len);

        allow_sync_reply(ls, &rc->rc_id);
        memset(ls->ls_recover_buf, 0, dlm_config.ci_buffer_size);

        send_rcom(ls, mh, rc);

        error = dlm_wait_function(ls, &rcom_response);
        disallow_sync_reply(ls);
 out:
        return error;
}

static void receive_rcom_names(struct dlm_ls *ls, struct dlm_rcom *rc_in)
{
        struct dlm_rcom *rc;
        struct dlm_mhandle *mh;
        int error, inlen, outlen, nodeid;

        nodeid = rc_in->rc_header.h_nodeid;
        inlen = rc_in->rc_header.h_length - sizeof(struct dlm_rcom);
        outlen = dlm_config.ci_buffer_size - sizeof(struct dlm_rcom);

        error = create_rcom(ls, nodeid, DLM_RCOM_NAMES_REPLY, outlen, &rc, &mh);
        if (error)
                return;
        rc->rc_id = rc_in->rc_id;
        rc->rc_seq_reply = rc_in->rc_seq;

        dlm_copy_master_names(ls, rc_in->rc_buf, inlen, rc->rc_buf, outlen,
                              nodeid);
        send_rcom(ls, mh, rc);
}

int dlm_send_rcom_lookup(struct dlm_rsb *r, int dir_nodeid)
{
        struct dlm_rcom *rc;
        struct dlm_mhandle *mh;
        struct dlm_ls *ls = r->res_ls;
        int error;

        error = create_rcom(ls, dir_nodeid, DLM_RCOM_LOOKUP, r->res_length,
                            &rc, &mh);
        if (error)
                goto out;
        memcpy(rc->rc_buf, r->res_name, r->res_length);
        rc->rc_id = (unsigned long) r->res_id;

        send_rcom(ls, mh, rc);
 out:
        return error;
}

int dlm_send_rcom_lookup_dump(struct dlm_rsb *r, int to_nodeid)
{
        struct dlm_rcom *rc;
        struct dlm_mhandle *mh;
        struct dlm_ls *ls = r->res_ls;
        int error;

        error = create_rcom(ls, to_nodeid, DLM_RCOM_LOOKUP, r->res_length,
                            &rc, &mh);
        if (error)
                goto out;
        memcpy(rc->rc_buf, r->res_name, r->res_length);
        rc->rc_id = 0xFFFFFFFF;

        send_rcom(ls, mh, rc);
 out:
        return error;
}

static void receive_rcom_lookup(struct dlm_ls *ls, struct dlm_rcom *rc_in)
{
        struct dlm_rcom *rc;
        struct dlm_mhandle *mh;
        int error, ret_nodeid, nodeid = rc_in->rc_header.h_nodeid;
        int len = rc_in->rc_header.h_length - sizeof(struct dlm_rcom);

        error = create_rcom(ls, nodeid, DLM_RCOM_LOOKUP_REPLY, 0, &rc, &mh);
        if (error)
                return;

        if (rc_in->rc_id == 0xFFFFFFFF) {
                log_error(ls, "receive_rcom_lookup dump from %d", nodeid);
                dlm_dump_rsb_name(ls, rc_in->rc_buf, len);
                return;
        }

        error = dlm_master_lookup(ls, nodeid, rc_in->rc_buf, len,
                                  DLM_LU_RECOVER_MASTER, &ret_nodeid, NULL);
        if (error)
                ret_nodeid = error;
        rc->rc_result = ret_nodeid;
        rc->rc_id = rc_in->rc_id;
        rc->rc_seq_reply = rc_in->rc_seq;

        send_rcom(ls, mh, rc);
}

static void receive_rcom_lookup_reply(struct dlm_ls *ls, struct dlm_rcom *rc_in)
{
        dlm_recover_master_reply(ls, rc_in);
}

static void pack_rcom_lock(struct dlm_rsb *r, struct dlm_lkb *lkb,
                           struct rcom_lock *rl)
{
        memset(rl, 0, sizeof(*rl));

        rl->rl_ownpid = cpu_to_le32(lkb->lkb_ownpid);
        rl->rl_lkid = cpu_to_le32(lkb->lkb_id);
        rl->rl_exflags = cpu_to_le32(lkb->lkb_exflags);
        rl->rl_flags = cpu_to_le32(lkb->lkb_flags);
        rl->rl_lvbseq = cpu_to_le32(lkb->lkb_lvbseq);
        rl->rl_rqmode = lkb->lkb_rqmode;
        rl->rl_grmode = lkb->lkb_grmode;
        rl->rl_status = lkb->lkb_status;
        rl->rl_wait_type = cpu_to_le16(lkb->lkb_wait_type);

        if (lkb->lkb_bastfn)
                rl->rl_asts |= DLM_CB_BAST;
        if (lkb->lkb_astfn)
                rl->rl_asts |= DLM_CB_CAST;

        rl->rl_namelen = cpu_to_le16(r->res_length);
        memcpy(rl->rl_name, r->res_name, r->res_length);

        /* FIXME: might we have an lvb without DLM_LKF_VALBLK set ?
           If so, receive_rcom_lock_args() won't take this copy. */

        if (lkb->lkb_lvbptr)
                memcpy(rl->rl_lvb, lkb->lkb_lvbptr, r->res_ls->ls_lvblen);
}

int dlm_send_rcom_lock(struct dlm_rsb *r, struct dlm_lkb *lkb)
{
        struct dlm_ls *ls = r->res_ls;
        struct dlm_rcom *rc;
        struct dlm_mhandle *mh;
        struct rcom_lock *rl;
        int error, len = sizeof(struct rcom_lock);

        if (lkb->lkb_lvbptr)
                len += ls->ls_lvblen;

        error = create_rcom(ls, r->res_nodeid, DLM_RCOM_LOCK, len, &rc, &mh);
        if (error)
                goto out;

        rl = (struct rcom_lock *) rc->rc_buf;
        pack_rcom_lock(r, lkb, rl);
        rc->rc_id = (unsigned long) r;

        send_rcom(ls, mh, rc);
 out:
        return error;
}

/* needs at least dlm_rcom + rcom_lock */
static void receive_rcom_lock(struct dlm_ls *ls, struct dlm_rcom *rc_in)
{
        struct dlm_rcom *rc;
        struct dlm_mhandle *mh;
        int error, nodeid = rc_in->rc_header.h_nodeid;

        dlm_recover_master_copy(ls, rc_in);

        error = create_rcom(ls, nodeid, DLM_RCOM_LOCK_REPLY,
                            sizeof(struct rcom_lock), &rc, &mh);
        if (error)
                return;

        /* We send back the same rcom_lock struct we received, but
           dlm_recover_master_copy() has filled in rl_remid and rl_result */

        memcpy(rc->rc_buf, rc_in->rc_buf, sizeof(struct rcom_lock));
        rc->rc_id = rc_in->rc_id;
        rc->rc_seq_reply = rc_in->rc_seq;

        send_rcom(ls, mh, rc);
}

/* If the lockspace doesn't exist then still send a status message
   back; it's possible that it just doesn't have its global_id yet. */

int dlm_send_ls_not_ready(int nodeid, struct dlm_rcom *rc_in)
{
        struct dlm_rcom *rc;
        struct rcom_config *rf;
        struct dlm_mhandle *mh;
        char *mb;
        int mb_len = sizeof(struct dlm_rcom) + sizeof(struct rcom_config);

        mh = dlm_lowcomms_get_buffer(nodeid, mb_len, GFP_NOFS, &mb);
        if (!mh)
                return -ENOBUFS;
        memset(mb, 0, mb_len);

        rc = (struct dlm_rcom *) mb;

        rc->rc_header.h_version = (DLM_HEADER_MAJOR | DLM_HEADER_MINOR);
        rc->rc_header.h_lockspace = rc_in->rc_header.h_lockspace;
        rc->rc_header.h_nodeid = dlm_our_nodeid();
        rc->rc_header.h_length = mb_len;
        rc->rc_header.h_cmd = DLM_RCOM;

        rc->rc_type = DLM_RCOM_STATUS_REPLY;
        rc->rc_id = rc_in->rc_id;
        rc->rc_seq_reply = rc_in->rc_seq;
        rc->rc_result = -ESRCH;

        rf = (struct rcom_config *) rc->rc_buf;
        rf->rf_lvblen = cpu_to_le32(~0U);

        dlm_rcom_out(rc);
        dlm_lowcomms_commit_buffer(mh);

        return 0;
}

/*
 * Ignore messages for stage Y before we set
 * recover_status bit for stage X:
 *
 * recover_status = 0
 *
 * dlm_recover_members()
 * - send nothing
 * - recv nothing
 * - ignore NAMES, NAMES_REPLY
 * - ignore LOOKUP, LOOKUP_REPLY
 * - ignore LOCK, LOCK_REPLY
 *
 * recover_status |= NODES
 *
 * dlm_recover_members_wait()
 *
 * dlm_recover_directory()
 * - send NAMES
 * - recv NAMES_REPLY
 * - ignore LOOKUP, LOOKUP_REPLY
 * - ignore LOCK, LOCK_REPLY
 *
 * recover_status |= DIR
 *
 * dlm_recover_directory_wait()
 *
 * dlm_recover_masters()
 * - send LOOKUP
 * - recv LOOKUP_REPLY
 *
 * dlm_recover_locks()
 * - send LOCKS
 * - recv LOCKS_REPLY
 *
 * recover_status |= LOCKS
 *
 * dlm_recover_locks_wait()
 *
 * recover_status |= DONE
 */

/* Called by dlm_recv; corresponds to dlm_receive_message() but special
   recovery-only comms are sent through here. */

void dlm_receive_rcom(struct dlm_ls *ls, struct dlm_rcom *rc, int nodeid)
{
        int lock_size = sizeof(struct dlm_rcom) + sizeof(struct rcom_lock);
        int stop, reply = 0, names = 0, lookup = 0, lock = 0;
        uint32_t status;
        uint64_t seq;

        switch (rc->rc_type) {
        case DLM_RCOM_STATUS_REPLY:
                reply = 1;
                break;
        case DLM_RCOM_NAMES:
                names = 1;
                break;
        case DLM_RCOM_NAMES_REPLY:
                names = 1;
                reply = 1;
                break;
        case DLM_RCOM_LOOKUP:
                lookup = 1;
                break;
        case DLM_RCOM_LOOKUP_REPLY:
                lookup = 1;
                reply = 1;
                break;
        case DLM_RCOM_LOCK:
                lock = 1;
                break;
        case DLM_RCOM_LOCK_REPLY:
                lock = 1;
                reply = 1;
                break;
        };

        spin_lock(&ls->ls_recover_lock);
        status = ls->ls_recover_status;
        stop = test_bit(LSFL_RECOVERY_STOP, &ls->ls_flags);
        seq = ls->ls_recover_seq;
        spin_unlock(&ls->ls_recover_lock);

        if (stop && (rc->rc_type != DLM_RCOM_STATUS))
                goto ignore;

        if (reply && (rc->rc_seq_reply != seq))
                goto ignore;

        if (!(status & DLM_RS_NODES) && (names || lookup || lock))
                goto ignore;

        if (!(status & DLM_RS_DIR) && (lookup || lock))
                goto ignore;

        switch (rc->rc_type) {
        case DLM_RCOM_STATUS:
                receive_rcom_status(ls, rc);
                break;

        case DLM_RCOM_NAMES:
                receive_rcom_names(ls, rc);
                break;

        case DLM_RCOM_LOOKUP:
                receive_rcom_lookup(ls, rc);
                break;

        case DLM_RCOM_LOCK:
                if (rc->rc_header.h_length < lock_size)
                        goto Eshort;
                receive_rcom_lock(ls, rc);
                break;

        case DLM_RCOM_STATUS_REPLY:
                receive_sync_reply(ls, rc);
                break;

        case DLM_RCOM_NAMES_REPLY:
                receive_sync_reply(ls, rc);
                break;

        case DLM_RCOM_LOOKUP_REPLY:
                receive_rcom_lookup_reply(ls, rc);
                break;

        case DLM_RCOM_LOCK_REPLY:
                if (rc->rc_header.h_length < lock_size)
                        goto Eshort;
                dlm_recover_process_copy(ls, rc);
                break;

        default:
                log_error(ls, "receive_rcom bad type %d", rc->rc_type);
        }
        return;

ignore:
        log_limit(ls, "dlm_receive_rcom ignore msg %d "
                  "from %d %llu %llu recover seq %llu sts %x gen %u",
                   rc->rc_type,
                   nodeid,
                   (unsigned long long)rc->rc_seq,
                   (unsigned long long)rc->rc_seq_reply,
                   (unsigned long long)seq,
                   status, ls->ls_generation);
        return;
Eshort:
        log_error(ls, "recovery message %d from %d is too short",
                  rc->rc_type, nodeid);
}