/*
 * GPL HEADER START
 *
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 only,
 * as published by the Free Software Foundation.
 *
 * 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 version 2 for more details (a copy is included
 * in the LICENSE file that accompanied this code).
 *
 * You should have received a copy of the GNU General Public License
 * version 2 along with this program; If not, see
 * http://www.gnu.org/licenses/gpl-2.0.html
 *
 * GPL HEADER END
 */
/*
 * Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
 * Use is subject to license terms.
 *
 * Copyright (c) 2011, 2015, Intel Corporation.
 */
/*
 * This file is part of Lustre, http://www.lustre.org/
 * Lustre is a trademark of Sun Microsystems, Inc.
 *
 * lustre/ptlrpc/recover.c
 *
 * Author: Mike Shaver <shaver@clusterfs.com>
 */

#define DEBUG_SUBSYSTEM S_RPC
#include "../../include/linux/libcfs/libcfs.h"

#include "../include/obd_support.h"
#include "../include/lustre_ha.h"
#include "../include/lustre_net.h"
#include "../include/lustre_import.h"
#include "../include/lustre_export.h"
#include "../include/obd.h"
#include "../include/obd_class.h"
#include <linux/list.h>

#include "ptlrpc_internal.h"

/**
 * Start recovery on disconnected import.
 * This is done by just attempting a connect
 */
void ptlrpc_initiate_recovery(struct obd_import *imp)
{
        CDEBUG(D_HA, "%s: starting recovery\n", obd2cli_tgt(imp->imp_obd));
        ptlrpc_connect_import(imp);
}

/**
 * Identify what request from replay list needs to be replayed next
 * (based on what we have already replayed) and send it to server.
 */
int ptlrpc_replay_next(struct obd_import *imp, int *inflight)
{
        int rc = 0;
        struct list_head *tmp, *pos;
        struct ptlrpc_request *req = NULL;
        __u64 last_transno;

        *inflight = 0;

        /* It might have committed some after we last spoke, so make sure we
         * get rid of them now.
         */
        spin_lock(&imp->imp_lock);
        imp->imp_last_transno_checked = 0;
        ptlrpc_free_committed(imp);
        last_transno = imp->imp_last_replay_transno;
        spin_unlock(&imp->imp_lock);

        CDEBUG(D_HA, "import %p from %s committed %llu last %llu\n",
               imp, obd2cli_tgt(imp->imp_obd),
               imp->imp_peer_committed_transno, last_transno);

        /* Do I need to hold a lock across this iteration?  We shouldn't be
         * racing with any additions to the list, because we're in recovery
         * and are therefore not processing additional requests to add.  Calls
         * to ptlrpc_free_committed might commit requests, but nothing "newer"
         * than the one we're replaying (it can't be committed until it's
         * replayed, and we're doing that here).  l_f_e_safe protects against
         * problems with the current request being committed, in the unlikely
         * event of that race.  So, in conclusion, I think that it's safe to
         * perform this list-walk without the imp_lock held.
         *
         * But, the {mdc,osc}_replay_open callbacks both iterate
         * request lists, and have comments saying they assume the
         * imp_lock is being held by ptlrpc_replay, but it's not. it's
         * just a little race...
         */

        /* Replay all the committed open requests on committed_list first */
        if (!list_empty(&imp->imp_committed_list)) {
                tmp = imp->imp_committed_list.prev;
                req = list_entry(tmp, struct ptlrpc_request, rq_replay_list);

                /* The last request on committed_list hasn't been replayed */
                if (req->rq_transno > last_transno) {
                        /* Since the imp_committed_list is immutable before
                         * all of it's requests being replayed, it's safe to
                         * use a cursor to accelerate the search
                         */
                        imp->imp_replay_cursor = imp->imp_replay_cursor->next;

                        while (imp->imp_replay_cursor !=
                               &imp->imp_committed_list) {
                                req = list_entry(imp->imp_replay_cursor,
                                                 struct ptlrpc_request,
                                                 rq_replay_list);
                                if (req->rq_transno > last_transno)
                                        break;

                                req = NULL;
                                imp->imp_replay_cursor =
                                        imp->imp_replay_cursor->next;
                        }
                } else {
                        /* All requests on committed_list have been replayed */
                        imp->imp_replay_cursor = &imp->imp_committed_list;
                        req = NULL;
                }
        }

        /* All the requests in committed list have been replayed, let's replay
         * the imp_replay_list
         */
        if (!req) {
                list_for_each_safe(tmp, pos, &imp->imp_replay_list) {
                        req = list_entry(tmp, struct ptlrpc_request,
                                         rq_replay_list);

                        if (req->rq_transno > last_transno)
                                break;
                        req = NULL;
                }
        }

        /* If need to resend the last sent transno (because a reconnect
         * has occurred), then stop on the matching req and send it again.
         * If, however, the last sent transno has been committed then we
         * continue replay from the next request.
         */
        if (req && imp->imp_resend_replay)
                lustre_msg_add_flags(req->rq_reqmsg, MSG_RESENT);

        spin_lock(&imp->imp_lock);
        imp->imp_resend_replay = 0;
        spin_unlock(&imp->imp_lock);

        if (req) {
                rc = ptlrpc_replay_req(req);
                if (rc) {
                        CERROR("recovery replay error %d for req %llu\n",
                               rc, req->rq_xid);
                        return rc;
                }
                *inflight = 1;
        }
        return rc;
}

/**
 * Schedule resending of request on sending_list. This is done after
 * we completed replaying of requests and locks.
 */
int ptlrpc_resend(struct obd_import *imp)
{
        struct ptlrpc_request *req, *next;

        /* As long as we're in recovery, nothing should be added to the sending
         * list, so we don't need to hold the lock during this iteration and
         * resend process.
         */
        /* Well... what if lctl recover is called twice at the same time?
         */
        spin_lock(&imp->imp_lock);
        if (imp->imp_state != LUSTRE_IMP_RECOVER) {
                spin_unlock(&imp->imp_lock);
                return -1;
        }

        list_for_each_entry_safe(req, next, &imp->imp_sending_list, rq_list) {
                LASSERTF((long)req > PAGE_SIZE && req != LP_POISON,
                         "req %p bad\n", req);
                LASSERTF(req->rq_type != LI_POISON, "req %p freed\n", req);
                if (!ptlrpc_no_resend(req))
                        ptlrpc_resend_req(req);
        }
        spin_unlock(&imp->imp_lock);

        return 0;
}

/**
 * Go through all requests in delayed list and wake their threads
 * for resending
 */
void ptlrpc_wake_delayed(struct obd_import *imp)
{
        struct list_head *tmp, *pos;
        struct ptlrpc_request *req;

        spin_lock(&imp->imp_lock);
        list_for_each_safe(tmp, pos, &imp->imp_delayed_list) {
                req = list_entry(tmp, struct ptlrpc_request, rq_list);

                DEBUG_REQ(D_HA, req, "waking (set %p):", req->rq_set);
                ptlrpc_client_wake_req(req);
        }
        spin_unlock(&imp->imp_lock);
}

void ptlrpc_request_handle_notconn(struct ptlrpc_request *failed_req)
{
        struct obd_import *imp = failed_req->rq_import;

        CDEBUG(D_HA, "import %s of %s@%s abruptly disconnected: reconnecting\n",
               imp->imp_obd->obd_name, obd2cli_tgt(imp->imp_obd),
               imp->imp_connection->c_remote_uuid.uuid);

        if (ptlrpc_set_import_discon(imp,
                              lustre_msg_get_conn_cnt(failed_req->rq_reqmsg))) {
                if (!imp->imp_replayable) {
                        CDEBUG(D_HA, "import %s@%s for %s not replayable, auto-deactivating\n",
                               obd2cli_tgt(imp->imp_obd),
                               imp->imp_connection->c_remote_uuid.uuid,
                               imp->imp_obd->obd_name);
                        ptlrpc_deactivate_import(imp);
                }
                /* to control recovery via lctl {disable|enable}_recovery */
                if (imp->imp_deactive == 0)
                        ptlrpc_connect_import(imp);
        }

        /* Wait for recovery to complete and resend. If evicted, then
         * this request will be errored out later.
         */
        spin_lock(&failed_req->rq_lock);
        if (!failed_req->rq_no_resend)
                failed_req->rq_resend = 1;
        spin_unlock(&failed_req->rq_lock);
}

/**
 * Administratively active/deactive a client.
 * This should only be called by the ioctl interface, currently
 *  - the lctl deactivate and activate commands
 *  - echo 0/1 >> /sys/fs/lustre/osc/XXX/active
 *  - client umount -f (ll_umount_begin)
 */
int ptlrpc_set_import_active(struct obd_import *imp, int active)
{
        struct obd_device *obd = imp->imp_obd;
        int rc = 0;

        LASSERT(obd);

        /* When deactivating, mark import invalid, and abort in-flight
         * requests.
         */
        if (!active) {
                LCONSOLE_WARN("setting import %s INACTIVE by administrator request\n",
                              obd2cli_tgt(imp->imp_obd));

                /* set before invalidate to avoid messages about imp_inval
                 * set without imp_deactive in ptlrpc_import_delay_req
                 */
                spin_lock(&imp->imp_lock);
                imp->imp_deactive = 1;
                spin_unlock(&imp->imp_lock);

                obd_import_event(imp->imp_obd, imp, IMP_EVENT_DEACTIVATE);

                ptlrpc_invalidate_import(imp);
        }

        /* When activating, mark import valid, and attempt recovery */
        if (active) {
                CDEBUG(D_HA, "setting import %s VALID\n",
                       obd2cli_tgt(imp->imp_obd));

                spin_lock(&imp->imp_lock);
                imp->imp_deactive = 0;
                spin_unlock(&imp->imp_lock);
                obd_import_event(imp->imp_obd, imp, IMP_EVENT_ACTIVATE);

                rc = ptlrpc_recover_import(imp, NULL, 0);
        }

        return rc;
}
EXPORT_SYMBOL(ptlrpc_set_import_active);

/* Attempt to reconnect an import */
int ptlrpc_recover_import(struct obd_import *imp, char *new_uuid, int async)
{
        int rc = 0;

        spin_lock(&imp->imp_lock);
        if (imp->imp_state == LUSTRE_IMP_NEW || imp->imp_deactive ||
            atomic_read(&imp->imp_inval_count))
                rc = -EINVAL;
        spin_unlock(&imp->imp_lock);
        if (rc)
                goto out;

        /* force import to be disconnected. */
        ptlrpc_set_import_discon(imp, 0);

        if (new_uuid) {
                struct obd_uuid uuid;

                /* intruct import to use new uuid */
                obd_str2uuid(&uuid, new_uuid);
                rc = import_set_conn_priority(imp, &uuid);
                if (rc)
                        goto out;
        }

        /* Check if reconnect is already in progress */
        spin_lock(&imp->imp_lock);
        if (imp->imp_state != LUSTRE_IMP_DISCON) {
                imp->imp_force_verify = 1;
                rc = -EALREADY;
        }
        spin_unlock(&imp->imp_lock);
        if (rc)
                goto out;

        rc = ptlrpc_connect_import(imp);
        if (rc)
                goto out;

        if (!async) {
                struct l_wait_info lwi;
                int secs = cfs_time_seconds(obd_timeout);

                CDEBUG(D_HA, "%s: recovery started, waiting %u seconds\n",
                       obd2cli_tgt(imp->imp_obd), secs);

                lwi = LWI_TIMEOUT(secs, NULL, NULL);
                rc = l_wait_event(imp->imp_recovery_waitq,
                                  !ptlrpc_import_in_recovery(imp), &lwi);
                CDEBUG(D_HA, "%s: recovery finished\n",
                       obd2cli_tgt(imp->imp_obd));
        }

out:
        return rc;
}
EXPORT_SYMBOL(ptlrpc_recover_import);

int ptlrpc_import_in_recovery(struct obd_import *imp)
{
        int in_recovery = 1;

        spin_lock(&imp->imp_lock);
        if (imp->imp_state == LUSTRE_IMP_FULL ||
            imp->imp_state == LUSTRE_IMP_CLOSED ||
            imp->imp_state == LUSTRE_IMP_DISCON ||
            imp->imp_obd->obd_no_recov)
                in_recovery = 0;
        spin_unlock(&imp->imp_lock);

        return in_recovery;
}