/*
 * Copyright (c) 2009 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Adam Hamsik.
 *
 * This code is further derived from software contributed to the
 * DragonFly project by Alex Hornung and Matthew Dillon
 *
 * 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
 *
 * $NetBSD: dm_target_stripe.c,v 1.9 2010/01/04 00:14:41 haad Exp $
 */

/*
 * This file implements initial version of device-mapper stripe target.
 *
 * DragonFly changes: Increase to an unlimited number of stripes
 */
#include <dev/disk/dm/dm.h>
#include <sys/malloc.h>         /* for malloc macros, dm.h includes sys/param.h */

MALLOC_DEFINE(M_DMSTRIPE, "dm_striped", "Device Mapper Target Striped");

#define MAX_STRIPES 32
/* #define USE_NUM_ERROR */

struct target_stripe_dev {
        dm_pdev_t *pdev;
        uint64_t offset;
        int num_error;
};

typedef struct target_stripe_config {
        int stripe_num;
        uint64_t stripe_chunksize;
        struct target_stripe_dev stripe_devs[0];
} dm_target_stripe_config_t;

static void dm_target_stripe_destroy_config(dm_target_stripe_config_t *tsc);

/*
 * Init function called from dm_table_load_ioctl.
 *
 * Example line sent to dm from lvm tools when using striped target.
 * start length striped #stripes chunk_size device1 offset1 ... deviceN offsetN
 */
static int
dm_target_stripe_init(dm_table_entry_t *table_en, int argc, char **argv)
{
        dm_target_stripe_config_t *tsc;
        char *arg;
        int i, n, siz, chunksize;

        if (argc < 2) {
                kprintf("Striped target takes 2 or more args\n");
                return EINVAL;
        }

        n = (int)atoi64(argv[0]);
        if (n <= 0 || n > MAX_STRIPES) {
                kprintf("dm: Error %d stripes not supported (%d max)\n",
                        n, MAX_STRIPES);
                return ENOTSUP;
        }
#if 0
        if (table_en->length % n) {
                kprintf("dm: Target device size not multiple of stripes\n");
                return EINVAL;
        }
#endif
        if (argc != (2 + n * 2)) {
                kprintf("dm: Invalid argc %d for %d stripe devices\n",
                        argc, n);
                return EINVAL;
        }

        chunksize = atoi64(argv[1]);
        if (chunksize < 1 || chunksize * DEV_BSIZE > MAXPHYS) {
                kprintf("dm: Error unsupported chunk size %jdKB\n",
                        (intmax_t)chunksize * DEV_BSIZE / 1024);
                return EINVAL;
        }
#if 0
        if ((table_en->length / n) % chunksize) {
                kprintf("dm: Stripe device size not multiple of chunk size\n");
                return EINVAL;
        }
#endif

        siz = sizeof(dm_target_stripe_config_t) +
                n * sizeof(struct target_stripe_dev);
        tsc = kmalloc(siz, M_DMSTRIPE, M_WAITOK | M_ZERO);
        if (tsc == NULL)
                return ENOMEM;
        tsc->stripe_num = n;
        tsc->stripe_chunksize = chunksize;

        /*
         * Parse the devices
         */

        kprintf("dm: Stripe %d devices chunk size %dKB\n",
                (int)tsc->stripe_num,
                (int)tsc->stripe_chunksize
        );

        argv += 2;
        for (n = 0, i = 0; n < tsc->stripe_num; ++n) {
                arg = argv[i++];
                KKASSERT(arg);
                tsc->stripe_devs[n].pdev = dm_pdev_insert(arg);
                if (tsc->stripe_devs[n].pdev == NULL)
                        break;
                arg = argv[i++];
                KKASSERT(arg);
                tsc->stripe_devs[n].offset = atoi64(arg);
                dm_table_add_deps(table_en, tsc->stripe_devs[n].pdev);
        }
        if (n != tsc->stripe_num) {
                dm_target_stripe_destroy_config(tsc);
                return (ENOENT);
        }

        dm_table_init_target(table_en, tsc);

        return 0;
}

/*
 * Info routine called to get params string.
 */
static char *
dm_target_stripe_info(void *target_config)
{
        dm_target_stripe_config_t *tsc;
        char *params;
        char *ptr;
        char buf[MAX_STRIPES + 1];
        size_t len;
        int ret;
        int i;

        tsc = target_config;

        len = DM_MAX_PARAMS_SIZE;
        params = dm_alloc_string(len);
        ptr = params;

        ret = ksnprintf(ptr, len, "%d ", tsc->stripe_num);
        ptr += ret;
        len -= ret;

        memset(buf, 0, sizeof(buf));
        for (i = 0; i < tsc->stripe_num; i++) {
                ret = ksnprintf(ptr, len, "%s ",
                        tsc->stripe_devs[i].pdev->udev_name);
                if (tsc->stripe_devs[i].num_error) /* no lock */
                        buf[i] = 'D';
                else
                        buf[i] = 'A';
                ptr += ret;
                len -= ret;
        }

        ret = ksnprintf(ptr, len, "1 %s", buf);
        ptr += ret;
        len -= ret;

        return params;
}

/*
 * Table routine called to get params string.
 */
static char *
dm_target_stripe_table(void *target_config)
{
        dm_target_stripe_config_t *tsc;
        char *params;
        char *ptr;
        size_t len;
        int ret;
        int i;

        tsc = target_config;

        len = DM_MAX_PARAMS_SIZE;
        params = dm_alloc_string(len);
        ptr = params;

        ret = ksnprintf(ptr, len, "%d %jd",
                tsc->stripe_num,
                (intmax_t)tsc->stripe_chunksize);
        ptr += ret;
        len -= ret;

        for (i = 0; i < tsc->stripe_num; i++) {
                ret = ksnprintf(ptr, len, " %s %jd",
                        tsc->stripe_devs[i].pdev->udev_name,
                        (intmax_t)tsc->stripe_devs[i].offset);
                ptr += ret;
                len -= ret;
        }

        return params;
}

#ifdef USE_NUM_ERROR
static void
dm_target_stripe_iodone(struct bio *bio)
{
        struct bio *obio;
        struct buf *bp;
        dm_target_stripe_config_t *tsc;

        bp = bio->bio_buf;
        tsc = bio->bio_caller_info1.ptr;

        if (bp->b_error) {
                int devnr;
                uint64_t blkno, stripe;

                blkno = bio->bio_offset / DEV_BSIZE;
                stripe = blkno / tsc->stripe_chunksize;
                devnr = stripe % tsc->stripe_num;
                KKASSERT(devnr < MAX_STRIPES);
                tsc->stripe_devs[devnr].num_error++;

                dmdebug("device=%d error=%d\n", devnr, bp->b_error);
        }

        obio = pop_bio(bio);
        biodone(obio);
}

static __inline
struct bio *get_stripe_bio(struct bio *bio, void *priv)
{
        struct bio *nbio;

        nbio = push_bio(bio);
        nbio->bio_caller_info1.ptr = priv;
        nbio->bio_done = dm_target_stripe_iodone;

        return nbio;
}
#else
static __inline
struct bio *get_stripe_bio(struct bio *bio, void *priv __unused)
{
        return bio;
}
#endif

/*
 * Strategy routine called from dm_strategy.
 */
static int
dm_target_stripe_strategy(dm_table_entry_t *table_en, struct buf *bp)
{
        dm_target_stripe_config_t *tsc;
        struct bio *bio = &bp->b_bio1;
        struct bio *nbio;
        struct buf *nestbuf;
        struct target_stripe_dev *dev;
        uint64_t blkno, blkoff;
        uint64_t stripe, blknr;
        uint32_t stripe_off, stripe_rest, num_blks, issue_blks;
        int devnr;

        tsc = table_en->target_config;
        if (tsc == NULL)
                return 0;

        /* calculate extent of request */
        KKASSERT(bp->b_resid % DEV_BSIZE == 0);

        switch(bp->b_cmd) {
        case BUF_CMD_READ:
        case BUF_CMD_WRITE:
        case BUF_CMD_FREEBLKS:
                /*
                 * Loop through to individual operations
                 */
                blkno = bio->bio_offset / DEV_BSIZE;
                blkoff = 0;
                num_blks = bp->b_resid / DEV_BSIZE;
                nestiobuf_init(bio);

                while (num_blks > 0) {
                        /* blockno to stripe piece nr */
                        stripe = blkno / tsc->stripe_chunksize;
                        stripe_off = blkno % tsc->stripe_chunksize;

                        /* where we are inside the stripe */
                        devnr = stripe % tsc->stripe_num;
                        blknr = stripe / tsc->stripe_num;
                        dev = &tsc->stripe_devs[devnr];

                        /* how much is left before we hit a boundary */
                        stripe_rest = tsc->stripe_chunksize - stripe_off;

                        /* issue this piece on stripe `stripe' */
                        issue_blks = MIN(stripe_rest, num_blks);
                        nestbuf = getpbuf(NULL);
                        nestbuf->b_flags |= bio->bio_buf->b_flags & B_HASBOGUS;

                        nestiobuf_add(bio, nestbuf, blkoff,
                                        issue_blks * DEV_BSIZE, NULL);

                        nbio = get_stripe_bio(&nestbuf->b_bio1, tsc);
                        nbio->bio_offset = blknr * tsc->stripe_chunksize;
                        nbio->bio_offset += stripe_off;
                        nbio->bio_offset += dev->offset;
                        nbio->bio_offset *= DEV_BSIZE;

                        vn_strategy(dev->pdev->pdev_vnode, nbio);

                        blkno += issue_blks;
                        blkoff += issue_blks * DEV_BSIZE;
                        num_blks -= issue_blks;
                }
                nestiobuf_start(bio);
                break;
        case BUF_CMD_FLUSH:
                nestiobuf_init(bio);
                for (devnr = 0; devnr < tsc->stripe_num; ++devnr) {
                        dev = &tsc->stripe_devs[devnr];
                        nestbuf = getpbuf(NULL);
                        nestbuf->b_flags |= bio->bio_buf->b_flags & B_HASBOGUS;

                        nestiobuf_add(bio, nestbuf, 0, 0, NULL);

                        nbio = get_stripe_bio(&nestbuf->b_bio1, tsc);
                        nbio->bio_offset = 0;

                        vn_strategy(dev->pdev->pdev_vnode, nbio);
                }
                nestiobuf_start(bio);
                break;
        default:
                bp->b_flags |= B_ERROR;
                bp->b_error = EIO;
                biodone(bio);
                break;
        }
        return 0;
}


static int
dm_target_stripe_dump(dm_table_entry_t *table_en, void *data, size_t length, off_t offset)
{
        dm_target_stripe_config_t *tsc;
        uint64_t blkno, blkoff;
        uint64_t stripe, blknr;
        uint32_t stripe_off, stripe_rest, num_blks, issue_blks;
        uint64_t off2, len2;
        int devnr;

        tsc = table_en->target_config;
        if (tsc == NULL)
                return 0;

        /* calculate extent of request */
        KKASSERT(length % DEV_BSIZE == 0);

        blkno = offset / DEV_BSIZE;
        blkoff = 0;
        num_blks = length / DEV_BSIZE;

        /*
         * 0 length means flush buffers and return
         */
        if (length == 0) {
                for (devnr = 0; devnr < tsc->stripe_num; ++devnr) {
                        if (tsc->stripe_devs[devnr].pdev->pdev_vnode->v_rdev == NULL)
                                return ENXIO;

                        dev_ddump(tsc->stripe_devs[devnr].pdev->pdev_vnode->v_rdev,
                            data, 0, offset, 0);
                }
                return 0;
        }

        while (num_blks > 0) {
                /* blockno to stripe piece nr */
                stripe = blkno / tsc->stripe_chunksize;
                stripe_off = blkno % tsc->stripe_chunksize;

                /* where we are inside the stripe */
                devnr = stripe % tsc->stripe_num;
                blknr = stripe / tsc->stripe_num;

                /* how much is left before we hit a boundary */
                stripe_rest = tsc->stripe_chunksize - stripe_off;

                /* issue this piece on stripe `stripe' */
                issue_blks = MIN(stripe_rest, num_blks);

#if 0
                nestiobuf_add(bio, nestbuf, blkoff,
                                issue_blks * DEV_BSIZE);
#endif
                len2 = issue_blks * DEV_BSIZE;

                /* I need number of bytes. */
                off2 = blknr * tsc->stripe_chunksize + stripe_off;
                off2 += tsc->stripe_devs[devnr].offset;
                off2 *= DEV_BSIZE;
                off2 = dm_pdev_correct_dump_offset(tsc->stripe_devs[devnr].pdev,
                    off2);

                if (tsc->stripe_devs[devnr].pdev->pdev_vnode->v_rdev == NULL)
                        return ENXIO;

                dev_ddump(tsc->stripe_devs[devnr].pdev->pdev_vnode->v_rdev,
                    (char *)data + blkoff, 0, off2, len2);

                blkno += issue_blks;
                blkoff += issue_blks * DEV_BSIZE;
                num_blks -= issue_blks;
        }

        return 0;
}

/*
 * Destroy a dm table entry for stripes.
 */
static int
dm_target_stripe_destroy(dm_table_entry_t *table_en)
{
        if (table_en->target_config != NULL)
                dm_target_stripe_destroy_config(table_en->target_config);

        return 0;
}

static void
dm_target_stripe_destroy_config(dm_target_stripe_config_t *tsc)
{
        int n;

        for (n = 0; n < tsc->stripe_num; ++n) {
                if (tsc->stripe_devs[n].pdev) {
                        dm_pdev_decr(tsc->stripe_devs[n].pdev);
                        tsc->stripe_devs[n].pdev = NULL;
                }
        }
        kfree(tsc, M_DMSTRIPE);
}

static int
dmts_mod_handler(module_t mod, int type, void *unused)
{
        dm_target_t *dmt = NULL;
        int err = 0;

        switch(type) {
        case MOD_LOAD:
                if ((dmt = dm_target_lookup("striped")) != NULL) {
                        dm_target_unbusy(dmt);
                        return EEXIST;
                }
                dmt = dm_target_alloc("striped");
                dmt->version[0] = 1;
                dmt->version[1] = 0;
                dmt->version[2] = 3;
                dmt->init = &dm_target_stripe_init;
                dmt->destroy = &dm_target_stripe_destroy;
                dmt->strategy = &dm_target_stripe_strategy;
                dmt->table = &dm_target_stripe_table;
                dmt->info = &dm_target_stripe_info;
                dmt->dump = &dm_target_stripe_dump;
                dmt->max_argc = 2 + (MAX_STRIPES * 2);

                err = dm_target_insert(dmt);
                if (err == 0)
                        kprintf("dm_target_striped: Successfully initialized\n");
                break;

        case MOD_UNLOAD:
                err = dm_target_remove("striped");
                if (err == 0)
                        kprintf("dm_target_striped: unloaded\n");
                break;
        }

        return err;
}

DM_TARGET_MODULE(dm_target_striped, dmts_mod_handler);