/*
 * Copyright (c) 2009 The DragonFly Project.  All rights reserved.
 *
 * This code is derived from software contributed to The DragonFly Project
 * by Matthew Dillon <dillon@backplane.com>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name of The DragonFly Project nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific, prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include "hammer.h"

static void rebalance_usage(int exit_code);

/*
 * rebalance <filesystem> [saturation_percentage] (default 85%)
 */
void
hammer_cmd_rebalance(char **av, int ac)
{
        struct hammer_ioc_rebalance rebal;
        const char *filesystem;
        int fd;
        int perc;

        if (TimeoutOpt > 0)
                alarm(TimeoutOpt);

        bzero(&rebal, sizeof(rebal));

        rebal.key_beg.localization = HAMMER_MIN_LOCALIZATION;
        rebal.key_beg.obj_id = HAMMER_MIN_OBJID;
        hammer_get_cycle(&rebal.key_beg, NULL);

        rebal.key_end.localization = HAMMER_MAX_LOCALIZATION;
        rebal.key_end.obj_id = HAMMER_MAX_OBJID;
        rebal.allpfs = AllPFS;

        if (ac == 0) {
                rebalance_usage(1);
                /* not reached */
        }
        filesystem = av[0];
        if (ac == 1) {
                perc = 85;
        } else {
                perc = strtol(av[1], NULL, 0);
                if (perc < 50 || perc > 100) {
                        rebalance_usage(1);
                        /* not reached */
                }
        }
        rebal.saturation = HAMMER_BTREE_INT_ELMS * perc / 100;

        printf("rebalance start %016jx:%04x\n",
                (uintmax_t)rebal.key_beg.obj_id,
                rebal.key_beg.localization);

        fd = open(filesystem, O_RDONLY);
        if (fd < 0) {
                err(1, "Unable to open %s", filesystem);
                /* not reached */
        }
        RunningIoctl = 1;
        if (ioctl(fd, HAMMERIOC_REBALANCE, &rebal) < 0) {
                printf("Rebalance %s failed: %s\n",
                       filesystem, strerror(errno));
        } else if (rebal.head.flags & HAMMER_IOC_HEAD_INTR) {
                printf("Rebalance %s interrupted by timer at %016jx:%04x\n",
                        filesystem,
                        (uintmax_t)rebal.key_cur.obj_id,
                        rebal.key_cur.localization);
                if (CyclePath)
                        hammer_set_cycle(&rebal.key_cur, 0);
        } else {
                if (CyclePath)
                        hammer_reset_cycle();
                printf("Rebalance %s succeeded\n", filesystem);
        }
        RunningIoctl = 0;
        close(fd);
        printf("Rebalance:\n"
               "    %jd B-Tree nodes scanned\n"
               "    %jd B-Tree nodes deleted\n"
               "    %jd collision retries\n"
               "    %jd B-Tree nodes rebalanced\n",
               (intmax_t)rebal.stat_ncount,
               (intmax_t)rebal.stat_deletions,
               (intmax_t)rebal.stat_collisions,
               (intmax_t)rebal.stat_nrebal
        );
}

static
void
rebalance_usage(int exit_code)
{
        fprintf(stderr,
                "hammer rebalance <filesystem> [saturation_percentage]\n"
                "saturation_percentage is 50%%-100%%, default is 85%%.\n");
        exit(exit_code);
}