/*
 * 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) 2007, 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/fid/fid_request.c
 *
 * Lustre Sequence Manager
 *
 * Author: Yury Umanets <umka@clusterfs.com>
 */

#define DEBUG_SUBSYSTEM S_FID

#include "../../include/linux/libcfs/libcfs.h"
#include <linux/module.h>

#include "../include/obd.h"
#include "../include/obd_class.h"
#include "../include/obd_support.h"
#include "../include/lustre_fid.h"
/* mdc RPC locks */
#include "../include/lustre_mdc.h"
#include "fid_internal.h"

static struct dentry *seq_debugfs_dir;

static int seq_client_rpc(struct lu_client_seq *seq,
                          struct lu_seq_range *output, __u32 opc,
                          const char *opcname)
{
        struct obd_export     *exp = seq->lcs_exp;
        struct ptlrpc_request *req;
        struct lu_seq_range   *out, *in;
        __u32                 *op;
        unsigned int           debug_mask;
        int                    rc;

        LASSERT(exp && !IS_ERR(exp));
        req = ptlrpc_request_alloc_pack(class_exp2cliimp(exp), &RQF_SEQ_QUERY,
                                        LUSTRE_MDS_VERSION, SEQ_QUERY);
        if (!req)
                return -ENOMEM;

        /* Init operation code */
        op = req_capsule_client_get(&req->rq_pill, &RMF_SEQ_OPC);
        *op = opc;

        /* Zero out input range, this is not recovery yet. */
        in = req_capsule_client_get(&req->rq_pill, &RMF_SEQ_RANGE);
        range_init(in);

        ptlrpc_request_set_replen(req);

        in->lsr_index = seq->lcs_space.lsr_index;
        if (seq->lcs_type == LUSTRE_SEQ_METADATA)
                fld_range_set_mdt(in);
        else
                fld_range_set_ost(in);

        if (opc == SEQ_ALLOC_SUPER) {
                req->rq_request_portal = SEQ_CONTROLLER_PORTAL;
                req->rq_reply_portal = MDC_REPLY_PORTAL;
                /* During allocating super sequence for data object,
                 * the current thread might hold the export of MDT0(MDT0
                 * precreating objects on this OST), and it will send the
                 * request to MDT0 here, so we can not keep resending the
                 * request here, otherwise if MDT0 is failed(umounted),
                 * it can not release the export of MDT0
                 */
                if (seq->lcs_type == LUSTRE_SEQ_DATA) {
                        req->rq_no_delay = 1;
                        req->rq_no_resend = 1;
                }
                debug_mask = D_CONSOLE;
        } else {
                if (seq->lcs_type == LUSTRE_SEQ_METADATA) {
                        req->rq_reply_portal = MDC_REPLY_PORTAL;
                        req->rq_request_portal = SEQ_METADATA_PORTAL;
                } else {
                        req->rq_reply_portal = OSC_REPLY_PORTAL;
                        req->rq_request_portal = SEQ_DATA_PORTAL;
                }
                debug_mask = D_INFO;
        }

        ptlrpc_at_set_req_timeout(req);

        if (opc != SEQ_ALLOC_SUPER && seq->lcs_type == LUSTRE_SEQ_METADATA)
                mdc_get_rpc_lock(exp->exp_obd->u.cli.cl_rpc_lock, NULL);
        rc = ptlrpc_queue_wait(req);
        if (opc != SEQ_ALLOC_SUPER && seq->lcs_type == LUSTRE_SEQ_METADATA)
                mdc_put_rpc_lock(exp->exp_obd->u.cli.cl_rpc_lock, NULL);
        if (rc)
                goto out_req;

        out = req_capsule_server_get(&req->rq_pill, &RMF_SEQ_RANGE);
        *output = *out;

        if (!range_is_sane(output)) {
                CERROR("%s: Invalid range received from server: "
                       DRANGE "\n", seq->lcs_name, PRANGE(output));
                rc = -EINVAL;
                goto out_req;
        }

        if (range_is_exhausted(output)) {
                CERROR("%s: Range received from server is exhausted: "
                       DRANGE "]\n", seq->lcs_name, PRANGE(output));
                rc = -EINVAL;
                goto out_req;
        }

        CDEBUG_LIMIT(debug_mask, "%s: Allocated %s-sequence " DRANGE "]\n",
                     seq->lcs_name, opcname, PRANGE(output));

out_req:
        ptlrpc_req_finished(req);
        return rc;
}

/* Request sequence-controller node to allocate new meta-sequence. */
static int seq_client_alloc_meta(const struct lu_env *env,
                                 struct lu_client_seq *seq)
{
        int rc;

        do {
                /* If meta server return -EINPROGRESS or EAGAIN,
                 * it means meta server might not be ready to
                 * allocate super sequence from sequence controller
                 * (MDT0)yet
                 */
                rc = seq_client_rpc(seq, &seq->lcs_space,
                                    SEQ_ALLOC_META, "meta");
        } while (rc == -EINPROGRESS || rc == -EAGAIN);

        return rc;
}

/* Allocate new sequence for client. */
static int seq_client_alloc_seq(const struct lu_env *env,
                                struct lu_client_seq *seq, u64 *seqnr)
{
        int rc;

        LASSERT(range_is_sane(&seq->lcs_space));

        if (range_is_exhausted(&seq->lcs_space)) {
                rc = seq_client_alloc_meta(env, seq);
                if (rc) {
                        CERROR("%s: Can't allocate new meta-sequence, rc %d\n",
                               seq->lcs_name, rc);
                        return rc;
                }
                CDEBUG(D_INFO, "%s: New range - " DRANGE "\n",
                       seq->lcs_name, PRANGE(&seq->lcs_space));
        } else {
                rc = 0;
        }

        LASSERT(!range_is_exhausted(&seq->lcs_space));
        *seqnr = seq->lcs_space.lsr_start;
        seq->lcs_space.lsr_start += 1;

        CDEBUG(D_INFO, "%s: Allocated sequence [%#llx]\n", seq->lcs_name,
               *seqnr);

        return rc;
}

static int seq_fid_alloc_prep(struct lu_client_seq *seq,
                              wait_queue_t *link)
{
        if (seq->lcs_update) {
                add_wait_queue(&seq->lcs_waitq, link);
                set_current_state(TASK_UNINTERRUPTIBLE);
                mutex_unlock(&seq->lcs_mutex);

                schedule();

                mutex_lock(&seq->lcs_mutex);
                remove_wait_queue(&seq->lcs_waitq, link);
                set_current_state(TASK_RUNNING);
                return -EAGAIN;
        }
        ++seq->lcs_update;
        mutex_unlock(&seq->lcs_mutex);
        return 0;
}

static void seq_fid_alloc_fini(struct lu_client_seq *seq)
{
        LASSERT(seq->lcs_update == 1);
        mutex_lock(&seq->lcs_mutex);
        --seq->lcs_update;
        wake_up(&seq->lcs_waitq);
}

/* Allocate new fid on passed client @seq and save it to @fid. */
int seq_client_alloc_fid(const struct lu_env *env,
                         struct lu_client_seq *seq, struct lu_fid *fid)
{
        wait_queue_t link;
        int rc;

        LASSERT(seq);
        LASSERT(fid);

        init_waitqueue_entry(&link, current);
        mutex_lock(&seq->lcs_mutex);

        if (OBD_FAIL_CHECK(OBD_FAIL_SEQ_EXHAUST))
                seq->lcs_fid.f_oid = seq->lcs_width;

        while (1) {
                u64 seqnr;

                if (!fid_is_zero(&seq->lcs_fid) &&
                    fid_oid(&seq->lcs_fid) < seq->lcs_width) {
                        /* Just bump last allocated fid and return to caller. */
                        seq->lcs_fid.f_oid += 1;
                        rc = 0;
                        break;
                }

                rc = seq_fid_alloc_prep(seq, &link);
                if (rc)
                        continue;

                rc = seq_client_alloc_seq(env, seq, &seqnr);
                if (rc) {
                        CERROR("%s: Can't allocate new sequence, rc %d\n",
                               seq->lcs_name, rc);
                        seq_fid_alloc_fini(seq);
                        mutex_unlock(&seq->lcs_mutex);
                        return rc;
                }

                CDEBUG(D_INFO, "%s: Switch to sequence [0x%16.16Lx]\n",
                       seq->lcs_name, seqnr);

                seq->lcs_fid.f_oid = LUSTRE_FID_INIT_OID;
                seq->lcs_fid.f_seq = seqnr;
                seq->lcs_fid.f_ver = 0;

                /*
                 * Inform caller that sequence switch is performed to allow it
                 * to setup FLD for it.
                 */
                rc = 1;

                seq_fid_alloc_fini(seq);
                break;
        }

        *fid = seq->lcs_fid;
        mutex_unlock(&seq->lcs_mutex);

        CDEBUG(D_INFO, "%s: Allocated FID "DFID"\n", seq->lcs_name,  PFID(fid));
        return rc;
}
EXPORT_SYMBOL(seq_client_alloc_fid);

/*
 * Finish the current sequence due to disconnect.
 * See mdc_import_event()
 */
void seq_client_flush(struct lu_client_seq *seq)
{
        wait_queue_t link;

        LASSERT(seq);
        init_waitqueue_entry(&link, current);
        mutex_lock(&seq->lcs_mutex);

        while (seq->lcs_update) {
                add_wait_queue(&seq->lcs_waitq, &link);
                set_current_state(TASK_UNINTERRUPTIBLE);
                mutex_unlock(&seq->lcs_mutex);

                schedule();

                mutex_lock(&seq->lcs_mutex);
                remove_wait_queue(&seq->lcs_waitq, &link);
                set_current_state(TASK_RUNNING);
        }

        fid_zero(&seq->lcs_fid);
        /**
         * this id shld not be used for seq range allocation.
         * set to -1 for dgb check.
         */

        seq->lcs_space.lsr_index = -1;

        range_init(&seq->lcs_space);
        mutex_unlock(&seq->lcs_mutex);
}
EXPORT_SYMBOL(seq_client_flush);

static void seq_client_debugfs_fini(struct lu_client_seq *seq)
{
        if (!IS_ERR_OR_NULL(seq->lcs_debugfs_entry))
                ldebugfs_remove(&seq->lcs_debugfs_entry);
}

static int seq_client_debugfs_init(struct lu_client_seq *seq)
{
        int rc;

        seq->lcs_debugfs_entry = ldebugfs_register(seq->lcs_name,
                                                   seq_debugfs_dir,
                                                   NULL, NULL);

        if (IS_ERR_OR_NULL(seq->lcs_debugfs_entry)) {
                CERROR("%s: LdebugFS failed in seq-init\n", seq->lcs_name);
                rc = seq->lcs_debugfs_entry ? PTR_ERR(seq->lcs_debugfs_entry)
                                            : -ENOMEM;
                seq->lcs_debugfs_entry = NULL;
                return rc;
        }

        rc = ldebugfs_add_vars(seq->lcs_debugfs_entry,
                               seq_client_debugfs_list, seq);
        if (rc) {
                CERROR("%s: Can't init sequence manager debugfs, rc %d\n",
                       seq->lcs_name, rc);
                goto out_cleanup;
        }

        return 0;

out_cleanup:
        seq_client_debugfs_fini(seq);
        return rc;
}

static void seq_client_fini(struct lu_client_seq *seq)
{
        seq_client_debugfs_fini(seq);

        if (seq->lcs_exp) {
                class_export_put(seq->lcs_exp);
                seq->lcs_exp = NULL;
        }
}

static int seq_client_init(struct lu_client_seq *seq,
                           struct obd_export *exp,
                           enum lu_cli_type type,
                           const char *prefix)
{
        int rc;

        LASSERT(seq);
        LASSERT(prefix);

        seq->lcs_type = type;

        mutex_init(&seq->lcs_mutex);
        if (type == LUSTRE_SEQ_METADATA)
                seq->lcs_width = LUSTRE_METADATA_SEQ_MAX_WIDTH;
        else
                seq->lcs_width = LUSTRE_DATA_SEQ_MAX_WIDTH;

        init_waitqueue_head(&seq->lcs_waitq);
        /* Make sure that things are clear before work is started. */
        seq_client_flush(seq);

        seq->lcs_exp = class_export_get(exp);

        snprintf(seq->lcs_name, sizeof(seq->lcs_name),
                 "cli-%s", prefix);

        rc = seq_client_debugfs_init(seq);
        if (rc)
                seq_client_fini(seq);
        return rc;
}

int client_fid_init(struct obd_device *obd,
                    struct obd_export *exp, enum lu_cli_type type)
{
        struct client_obd *cli = &obd->u.cli;
        char *prefix;
        int rc;

        cli->cl_seq = kzalloc(sizeof(*cli->cl_seq), GFP_NOFS);
        if (!cli->cl_seq)
                return -ENOMEM;

        prefix = kzalloc(MAX_OBD_NAME + 5, GFP_NOFS);
        if (!prefix) {
                rc = -ENOMEM;
                goto out_free_seq;
        }

        snprintf(prefix, MAX_OBD_NAME + 5, "cli-%s", obd->obd_name);

        /* Init client side sequence-manager */
        rc = seq_client_init(cli->cl_seq, exp, type, prefix);
        kfree(prefix);
        if (rc)
                goto out_free_seq;

        return rc;
out_free_seq:
        kfree(cli->cl_seq);
        cli->cl_seq = NULL;
        return rc;
}
EXPORT_SYMBOL(client_fid_init);

int client_fid_fini(struct obd_device *obd)
{
        struct client_obd *cli = &obd->u.cli;

        if (cli->cl_seq) {
                seq_client_fini(cli->cl_seq);
                kfree(cli->cl_seq);
                cli->cl_seq = NULL;
        }

        return 0;
}
EXPORT_SYMBOL(client_fid_fini);

static int __init fid_init(void)
{
        seq_debugfs_dir = ldebugfs_register(LUSTRE_SEQ_NAME,
                                            debugfs_lustre_root,
                                            NULL, NULL);
        return PTR_ERR_OR_ZERO(seq_debugfs_dir);
}

static void __exit fid_exit(void)
{
        if (!IS_ERR_OR_NULL(seq_debugfs_dir))
                ldebugfs_remove(&seq_debugfs_dir);
}

MODULE_AUTHOR("OpenSFS, Inc. <http://www.lustre.org/>");
MODULE_DESCRIPTION("Lustre File IDentifier");
MODULE_VERSION(LUSTRE_VERSION_STRING);
MODULE_LICENSE("GPL");

module_init(fid_init);
module_exit(fid_exit);