/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2012 Alexander Motin <mav@FreeBSD.org>
 * All rights reserved.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS 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 AUTHORS 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 <sys/param.h>
#include <sys/bio.h>
#include <sys/endian.h>
#include <sys/kernel.h>
#include <sys/kobj.h>
#include <sys/limits.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/sysctl.h>
#include <sys/systm.h>
#include <geom/geom.h>
#include "geom/raid/g_raid.h"
#include "g_raid_tr_if.h"

static MALLOC_DEFINE(M_TR_RAID5, "tr_raid5_data", "GEOM_RAID RAID5 data");

#define TR_RAID5_NONE 0
#define TR_RAID5_REBUILD 1
#define TR_RAID5_RESYNC 2

#define TR_RAID5_F_DOING_SOME   0x1
#define TR_RAID5_F_LOCKED       0x2
#define TR_RAID5_F_ABORT        0x4

struct g_raid_tr_raid5_object {
        struct g_raid_tr_object  trso_base;
        int                      trso_starting;
        int                      trso_stopping;
        int                      trso_type;
        int                      trso_recover_slabs; /* slabs before rest */
        int                      trso_fair_io;
        int                      trso_meta_update;
        int                      trso_flags;
        struct g_raid_subdisk   *trso_failed_sd; /* like per volume */
        void                    *trso_buffer;    /* Buffer space */
        struct bio               trso_bio;
};

static g_raid_tr_taste_t g_raid_tr_taste_raid5;
static g_raid_tr_event_t g_raid_tr_event_raid5;
static g_raid_tr_start_t g_raid_tr_start_raid5;
static g_raid_tr_stop_t g_raid_tr_stop_raid5;
static g_raid_tr_iostart_t g_raid_tr_iostart_raid5;
static g_raid_tr_iodone_t g_raid_tr_iodone_raid5;
static g_raid_tr_kerneldump_t g_raid_tr_kerneldump_raid5;
static g_raid_tr_locked_t g_raid_tr_locked_raid5;
static g_raid_tr_free_t g_raid_tr_free_raid5;

static kobj_method_t g_raid_tr_raid5_methods[] = {
        KOBJMETHOD(g_raid_tr_taste,     g_raid_tr_taste_raid5),
        KOBJMETHOD(g_raid_tr_event,     g_raid_tr_event_raid5),
        KOBJMETHOD(g_raid_tr_start,     g_raid_tr_start_raid5),
        KOBJMETHOD(g_raid_tr_stop,      g_raid_tr_stop_raid5),
        KOBJMETHOD(g_raid_tr_iostart,   g_raid_tr_iostart_raid5),
        KOBJMETHOD(g_raid_tr_iodone,    g_raid_tr_iodone_raid5),
        KOBJMETHOD(g_raid_tr_kerneldump, g_raid_tr_kerneldump_raid5),
        KOBJMETHOD(g_raid_tr_locked,    g_raid_tr_locked_raid5),
        KOBJMETHOD(g_raid_tr_free,      g_raid_tr_free_raid5),
        { 0, 0 }
};

static struct g_raid_tr_class g_raid_tr_raid5_class = {
        "RAID5",
        g_raid_tr_raid5_methods,
        sizeof(struct g_raid_tr_raid5_object),
        .trc_enable = 1,
        .trc_priority = 100
};

static int
g_raid_tr_taste_raid5(struct g_raid_tr_object *tr, struct g_raid_volume *vol)
{
        struct g_raid_tr_raid5_object *trs;
        u_int qual;

        trs = (struct g_raid_tr_raid5_object *)tr;
        qual = tr->tro_volume->v_raid_level_qualifier;
        if (tr->tro_volume->v_raid_level == G_RAID_VOLUME_RL_RAID4 &&
            (qual == G_RAID_VOLUME_RLQ_R4P0 ||
             qual == G_RAID_VOLUME_RLQ_R4PN)) {
                /* RAID4 */
        } else if ((tr->tro_volume->v_raid_level == G_RAID_VOLUME_RL_RAID5 ||
             tr->tro_volume->v_raid_level == G_RAID_VOLUME_RL_RAID5E ||
             tr->tro_volume->v_raid_level == G_RAID_VOLUME_RL_RAID5EE ||
             tr->tro_volume->v_raid_level == G_RAID_VOLUME_RL_RAID5R ||
             tr->tro_volume->v_raid_level == G_RAID_VOLUME_RL_RAID6 ||
             tr->tro_volume->v_raid_level == G_RAID_VOLUME_RL_RAIDMDF) &&
            (qual == G_RAID_VOLUME_RLQ_R5RA ||
             qual == G_RAID_VOLUME_RLQ_R5RS ||
             qual == G_RAID_VOLUME_RLQ_R5LA ||
             qual == G_RAID_VOLUME_RLQ_R5LS)) {
                /* RAID5/5E/5EE/5R/6/MDF */
        } else
                return (G_RAID_TR_TASTE_FAIL);
        trs->trso_starting = 1;
        return (G_RAID_TR_TASTE_SUCCEED);
}

static int
g_raid_tr_update_state_raid5(struct g_raid_volume *vol,
    struct g_raid_subdisk *sd)
{
        struct g_raid_tr_raid5_object *trs;
        struct g_raid_softc *sc;
        u_int s;
        int na, ns, nu;

        sc = vol->v_softc;
        trs = (struct g_raid_tr_raid5_object *)vol->v_tr;
        if (trs->trso_stopping &&
            (trs->trso_flags & TR_RAID5_F_DOING_SOME) == 0)
                s = G_RAID_VOLUME_S_STOPPED;
        else if (trs->trso_starting)
                s = G_RAID_VOLUME_S_STARTING;
        else {
                na = g_raid_nsubdisks(vol, G_RAID_SUBDISK_S_ACTIVE);
                ns = g_raid_nsubdisks(vol, G_RAID_SUBDISK_S_STALE) +
                     g_raid_nsubdisks(vol, G_RAID_SUBDISK_S_RESYNC);
                nu = g_raid_nsubdisks(vol, G_RAID_SUBDISK_S_UNINITIALIZED);
                if (na == vol->v_disks_count)
                        s = G_RAID_VOLUME_S_OPTIMAL;
                else if (na + ns == vol->v_disks_count ||
                    na + ns + nu == vol->v_disks_count /* XXX: Temporary. */)
                        s = G_RAID_VOLUME_S_SUBOPTIMAL;
                else if (na == vol->v_disks_count - 1 ||
                    na + ns + nu == vol->v_disks_count)
                        s = G_RAID_VOLUME_S_DEGRADED;
                else
                        s = G_RAID_VOLUME_S_BROKEN;
        }
        if (s != vol->v_state) {
                g_raid_event_send(vol, G_RAID_VOLUME_S_ALIVE(s) ?
                    G_RAID_VOLUME_E_UP : G_RAID_VOLUME_E_DOWN,
                    G_RAID_EVENT_VOLUME);
                g_raid_change_volume_state(vol, s);
                if (!trs->trso_starting && !trs->trso_stopping)
                        g_raid_write_metadata(sc, vol, NULL, NULL);
        }
        return (0);
}

static int
g_raid_tr_event_raid5(struct g_raid_tr_object *tr,
    struct g_raid_subdisk *sd, u_int event)
{

        g_raid_tr_update_state_raid5(tr->tro_volume, sd);
        return (0);
}

static int
g_raid_tr_start_raid5(struct g_raid_tr_object *tr)
{
        struct g_raid_tr_raid5_object *trs;
        struct g_raid_volume *vol;

        trs = (struct g_raid_tr_raid5_object *)tr;
        trs->trso_starting = 0;
        vol = tr->tro_volume;
        vol->v_read_only = 1;
        g_raid_tr_update_state_raid5(vol, NULL);
        return (0);
}

static int
g_raid_tr_stop_raid5(struct g_raid_tr_object *tr)
{
        struct g_raid_tr_raid5_object *trs;
        struct g_raid_volume *vol;

        trs = (struct g_raid_tr_raid5_object *)tr;
        vol = tr->tro_volume;
        trs->trso_starting = 0;
        trs->trso_stopping = 1;
        g_raid_tr_update_state_raid5(vol, NULL);
        return (0);
}

static void
g_raid_tr_iostart_raid5_read(struct g_raid_tr_object *tr, struct bio *bp)
{
        struct g_raid_volume *vol;
        struct g_raid_subdisk *sd;
        struct bio_queue_head queue;
        struct bio *cbp;
        char *addr;
        off_t offset, start, length, nstripe, remain;
        int no, pno, ddisks, pdisks, protate, pleft;
        u_int strip_size, lvl, qual;

        vol = tr->tro_volume;
        addr = bp->bio_data;
        strip_size = vol->v_strip_size;
        lvl = tr->tro_volume->v_raid_level;
        qual = tr->tro_volume->v_raid_level_qualifier;
        protate = tr->tro_volume->v_rotate_parity;

        /* Stripe number. */
        nstripe = bp->bio_offset / strip_size;
        /* Start position in stripe. */
        start = bp->bio_offset % strip_size;
        /* Number of data and parity disks. */
        if (lvl == G_RAID_VOLUME_RL_RAIDMDF)
                pdisks = tr->tro_volume->v_mdf_pdisks;
        else if (lvl == G_RAID_VOLUME_RL_RAID5EE ||
            lvl == G_RAID_VOLUME_RL_RAID6)
                pdisks = 2;
        else
                pdisks = 1;
        ddisks = vol->v_disks_count - pdisks;
        /* Parity disk number. */
        if (lvl == G_RAID_VOLUME_RL_RAID4) {
                if (qual == 0)          /* P0 */
                        pno = 0;
                else                    /* PN */
                        pno = ddisks;
                pleft = -1;
        } else {
                pno = (nstripe / (ddisks * protate)) % vol->v_disks_count;
                pleft = protate - (nstripe / ddisks) % protate;
                if (qual >= 2) {        /* PN/Left */
                        pno = ddisks - pno;
                        if (pno < 0)
                                pno += vol->v_disks_count;
                }
        }
        /* Data disk number. */
        no = nstripe % ddisks;
        if (lvl == G_RAID_VOLUME_RL_RAID4) {
                if (qual == 0)
                        no += pdisks;
        } else if (qual & 1) {  /* Continuation/Symmetric */
                no = (pno + pdisks + no) % vol->v_disks_count;
        } else if (no >= pno)   /* Restart/Asymmetric */
                no += pdisks;
        else
                no += imax(0, pno + pdisks - vol->v_disks_count);
        /* Stripe start position in disk. */
        offset = (nstripe / ddisks) * strip_size;
        /* Length of data to operate. */
        remain = bp->bio_length;

        bioq_init(&queue);
        do {
                length = MIN(strip_size - start, remain);
                cbp = g_clone_bio(bp);
                if (cbp == NULL)
                        goto failure;
                cbp->bio_offset = offset + start;
                cbp->bio_data = addr;
                cbp->bio_length = length;
                cbp->bio_caller1 = &vol->v_subdisks[no];
                bioq_insert_tail(&queue, cbp);
                no++;
                if (lvl == G_RAID_VOLUME_RL_RAID4) {
                        no %= vol->v_disks_count;
                        if (no == pno)
                                no = (no + pdisks) % vol->v_disks_count;
                } else if (qual & 1) {  /* Continuation/Symmetric */
                        no %= vol->v_disks_count;
                        if (no == pno) {
                                if ((--pleft) <= 0) {
                                        pleft += protate;
                                        if (qual < 2)   /* P0/Right */
                                                pno++;
                                        else            /* PN/Left */
                                                pno += vol->v_disks_count - 1;
                                        pno %= vol->v_disks_count;
                                }
                                no = (pno + pdisks) % vol->v_disks_count;
                                offset += strip_size;
                        }
                } else {                /* Restart/Asymmetric */
                        if (no == pno)
                                no += pdisks;
                        if (no >= vol->v_disks_count) {
                                no -= vol->v_disks_count;
                                if ((--pleft) <= 0) {
                                        pleft += protate;
                                        if (qual < 2)   /* P0/Right */
                                                pno++;
                                        else            /* PN/Left */
                                                pno += vol->v_disks_count - 1;
                                        pno %= vol->v_disks_count;
                                }
                                if (no == pno)
                                        no += pdisks;
                                else
                                        no += imax(0, pno + pdisks - vol->v_disks_count);
                                offset += strip_size;
                        }
                }
                remain -= length;
                addr += length;
                start = 0;
        } while (remain > 0);
        while ((cbp = bioq_takefirst(&queue)) != NULL) {
                sd = cbp->bio_caller1;
                cbp->bio_caller1 = NULL;
                g_raid_subdisk_iostart(sd, cbp);
        }
        return;
failure:
        while ((cbp = bioq_takefirst(&queue)) != NULL)
                g_destroy_bio(cbp);
        if (bp->bio_error == 0)
                bp->bio_error = ENOMEM;
        g_raid_iodone(bp, bp->bio_error);
}

static void
g_raid_tr_iostart_raid5(struct g_raid_tr_object *tr, struct bio *bp)
{
        struct g_raid_volume *vol;

        vol = tr->tro_volume;
        if (vol->v_state < G_RAID_VOLUME_S_SUBOPTIMAL) {
                g_raid_iodone(bp, EIO);
                return;
        }
        switch (bp->bio_cmd) {
        case BIO_READ:
                g_raid_tr_iostart_raid5_read(tr, bp);
                break;
        case BIO_WRITE:
        case BIO_DELETE:
        case BIO_FLUSH:
        case BIO_SPEEDUP:
                g_raid_iodone(bp, ENODEV);
                break;
        default:
                KASSERT(1 == 0, ("Invalid command here: %u (volume=%s)",
                    bp->bio_cmd, vol->v_name));
                break;
        }
}

static void
g_raid_tr_iodone_raid5(struct g_raid_tr_object *tr,
    struct g_raid_subdisk *sd, struct bio *bp)
{
        struct bio *pbp;

        pbp = bp->bio_parent;
        if (pbp->bio_error == 0)
                pbp->bio_error = bp->bio_error;
        pbp->bio_inbed++;
        g_destroy_bio(bp);
        if (pbp->bio_children == pbp->bio_inbed) {
                pbp->bio_completed = pbp->bio_length;
                g_raid_iodone(pbp, pbp->bio_error);
        }
}

static int
g_raid_tr_kerneldump_raid5(struct g_raid_tr_object *tr, void *virtual,
    off_t offset, size_t length)
{

        return (ENODEV);
}

static int
g_raid_tr_locked_raid5(struct g_raid_tr_object *tr, void *argp)
{
        struct bio *bp;
        struct g_raid_subdisk *sd;

        bp = (struct bio *)argp;
        sd = (struct g_raid_subdisk *)bp->bio_caller1;
        g_raid_subdisk_iostart(sd, bp);

        return (0);
}

static int
g_raid_tr_free_raid5(struct g_raid_tr_object *tr)
{
        struct g_raid_tr_raid5_object *trs;

        trs = (struct g_raid_tr_raid5_object *)tr;

        if (trs->trso_buffer != NULL) {
                free(trs->trso_buffer, M_TR_RAID5);
                trs->trso_buffer = NULL;
        }
        return (0);
}

G_RAID_TR_DECLARE(raid5, "RAID5");