/*-
 * Copyright (c) 1997, 1998, 1999
 *      Nan Yang Computer Services Limited.  All rights reserved.
 *
 *  Parts copyright (c) 1997, 1998 Cybernet Corporation, NetMAX project.
 *
 *  Written by Greg Lehey
 *
 *  This software is distributed under the so-called ``Berkeley
 *  License'':
 *
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by Nan Yang Computer
 *      Services Limited.
 * 4. Neither the name of the Company 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 ``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 company 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.
 *
 * $Id: vinumrevive.c,v 1.14 2000/12/21 01:55:11 grog Exp grog $
 * $FreeBSD: src/sys/dev/vinum/vinumrevive.c,v 1.22.2.5 2001/03/13 02:59:43 grog Exp $
 */

#include "vinumhdr.h"
#include "request.h"

/*
 * Revive a block of a subdisk.  Return an error
 * indication.  EAGAIN means successful copy, but
 * that more blocks remain to be copied.  EINVAL
 * means that the subdisk isn't associated with a
 * plex (which means a programming error if we get
 * here at all; FIXME).
 */

int
revive_block(int sdno)
{
    struct sd *sd;
    struct plex *plex;
    struct volume *vol;
    struct buf *bp;
    cdev_t dev;
    int error = EAGAIN;
    int size;                                               /* size of revive block, bytes */
    vinum_off_t plexblkno;                                          /* lblkno in plex */
    int psd;                                                /* parity subdisk number */
    u_int64_t stripe;                                       /* stripe number */
    int paritysd = 0;                                       /* set if this is the parity stripe */
    struct rangelock *lock;                                 /* for locking */
    vinum_off_t stripeoffset;                               /* offset in stripe */

    plexblkno = 0;                                          /* to keep the compiler happy */
    sd = &SD[sdno];
    lock = NULL;
    if (sd->plexno < 0)                                     /* no plex? */
        return EINVAL;
    plex = &PLEX[sd->plexno];                               /* point to plex */
    if (plex->volno >= 0)
        vol = &VOL[plex->volno];
    else
        vol = NULL;

    if ((sd->revive_blocksize == 0)                         /* no block size */
    ||(sd->revive_blocksize & ((1 << DEV_BSHIFT) - 1)))     /* or invalid block size */
        sd->revive_blocksize = DEFAULT_REVIVE_BLOCKSIZE;
    else if (sd->revive_blocksize > MAX_REVIVE_BLOCKSIZE)
        sd->revive_blocksize = MAX_REVIVE_BLOCKSIZE;
    size = u64min(sd->revive_blocksize >> DEV_BSHIFT, sd->sectors - sd->revived) << DEV_BSHIFT;
    sd->reviver = curproc->p_pid;                           /* note who last had a bash at it */

    /* Now decide where to read from */
    switch (plex->organization) {
    case plex_concat:
        plexblkno = sd->revived + sd->plexoffset;           /* corresponding address in plex */
        break;

    case plex_striped:
        stripeoffset = sd->revived % plex->stripesize;      /* offset from beginning of stripe */
        if (stripeoffset + (size >> DEV_BSHIFT) > plex->stripesize)
            size = (plex->stripesize - stripeoffset) << DEV_BSHIFT;
        plexblkno = sd->plexoffset                          /* base */
            + (sd->revived - stripeoffset) * plex->subdisks /* offset to beginning of stripe */
            + stripeoffset;                                 /* offset from beginning of stripe */
        break;

    case plex_raid4:
    case plex_raid5:
        stripeoffset = sd->revived % plex->stripesize;      /* offset from beginning of stripe */
        plexblkno = sd->plexoffset                          /* base */
            + (sd->revived - stripeoffset) * (plex->subdisks - 1) /* offset to beginning of stripe */
            +stripeoffset;                                  /* offset from beginning of stripe */
        stripe = (sd->revived / plex->stripesize);          /* stripe number */

        /* Make sure we don't go beyond the end of the band. */
        size = u64min(size, (plex->stripesize - stripeoffset) << DEV_BSHIFT);
        if (plex->organization == plex_raid4)
            psd = plex->subdisks - 1;                       /* parity subdisk for this stripe */
        else
            psd = plex->subdisks - 1 - stripe % plex->subdisks; /* parity subdisk for this stripe */
        paritysd = plex->sdnos[psd] == sdno;                /* note if it's the parity subdisk */

        /*
         * Now adjust for the strangenesses
         * in RAID-4 and RAID-5 striping.
         */
        if (sd->plexsdno > psd)                             /* beyond the parity stripe, */
            plexblkno -= plex->stripesize;                  /* one stripe less */
        else if (paritysd)
            plexblkno -= plex->stripesize * sd->plexsdno;   /* go back to the beginning of the band */
        break;

    case plex_disorg:                                       /* to keep the compiler happy */
        break;
    }

    if (paritysd) {                                         /* we're reviving a parity block, */
        bp = parityrebuild(plex, sd->revived, size, rebuildparity, &lock, NULL); /* do the grunt work */
        if (bp == NULL)                                     /* no buffer space */
            return ENOMEM;                                  /* chicken out */
    } else {                                                /* data block */
        bp = getpbuf(&vinum_conf.physbufs);                 /* Get a buffer */
        bp->b_data = Malloc(size);

        /*
         * Amount to transfer: block size, unless it
         * would overlap the end.
         */
        bp->b_bcount = size;
        bp->b_resid = bp->b_bcount;
        bp->b_bio1.bio_offset = (off_t)plexblkno << DEV_BSHIFT;             /* start here */
        bp->b_bio1.bio_done = biodone_sync;
        bp->b_bio1.bio_flags |= BIO_SYNC;
        if (isstriped(plex))                                /* we need to lock striped plexes */
            lock = lockrange(plexblkno << DEV_BSHIFT, bp, plex); /* lock it */
        if (vol != NULL)                                    /* it's part of a volume, */
            /*
               * First, read the data from the volume.  We
               * don't care which plex, that's bre's job.
             */
            dev = vol->vol_dev;
        else                                                /* it's an unattached plex */
            dev = PLEX[sd->plexno].plex_dev;

        bp->b_cmd = BUF_CMD_READ;
        vinumstart(dev, &bp->b_bio1, 1);
        biowait(&bp->b_bio1, "drvrd");
    }

    if (bp->b_flags & B_ERROR)
        error = bp->b_error;
    else
        /* Now write to the subdisk */
    {
        dev = SD[sdno].sd_dev;
        KKASSERT(dev != NULL);
        bp->b_cmd = BUF_CMD_WRITE;
        bp->b_resid = bp->b_bcount;
        bp->b_bio1.bio_offset = (off_t)sd->revived << DEV_BSHIFT;                   /* write it to here */
        bp->b_bio1.bio_driver_info = dev;
        bp->b_bio1.bio_done = biodone_sync;
        sdio(&bp->b_bio1);                                  /* perform the I/O */
        biowait(&bp->b_bio1, "drvwr");
        if (bp->b_flags & B_ERROR)
            error = bp->b_error;
        else {
            sd->revived += bp->b_bcount >> DEV_BSHIFT;      /* moved this much further down */
            if (sd->revived >= sd->sectors) {               /* finished */
                sd->revived = 0;
                set_sd_state(sdno, sd_up, setstate_force);  /* bring the sd up */
                log(LOG_INFO, "vinum: %s is %s\n", sd->name, sd_state(sd->state));
                save_config();                              /* and save the updated configuration */
                error = 0;                                  /* we're done */
            }
        }
        if (lock)                                           /* we took a lock, */
            unlockrange(sd->plexno, lock);                  /* give it back */
        while (sd->waitlist) {                              /* we have waiting requests */
#ifdef VINUMDEBUG
            struct request *rq = sd->waitlist;
            cdev_t dev;

            if (debug & DEBUG_REVIVECONFLICT) {
                dev = rq->bio->bio_driver_info;
                log(LOG_DEBUG,
                    "Relaunch revive conflict sd %d: %p\n%s dev %d.%d, offset 0x%jx, length %d\n",
                    rq->sdno,
                    rq,
                    (rq->bio->bio_buf->b_cmd == BUF_CMD_READ) ? "Read" : "Write",
                    major(dev),
                    minor(dev),
                    (uintmax_t)rq->bio->bio_offset,
                    rq->bio->bio_buf->b_bcount);
            }
#endif
            launch_requests(sd->waitlist, 1);               /* do them now */
            sd->waitlist = sd->waitlist->next;              /* and move on to the next */
        }
    }
    Free(bp->b_data);
    relpbuf(bp, &vinum_conf.physbufs);
    return error;
}

/*
 * Check or rebuild the parity blocks of a RAID-4
 * or RAID-5 plex.
 *
 * The variables plex->checkblock and
 * plex->rebuildblock represent the
 * subdisk-relative address of the stripe we're
 * looking at, not the plex-relative address.  We
 * store it in the plex and not as a local
 * variable because this function could be
 * stopped, and we don't want to repeat the part
 * we've already done.  This is also the reason
 * why we don't initialize it here except at the
 * end.  It gets initialized with the plex on
 * creation.
 *
 * Each call to this function processes at most
 * one stripe.  We can't loop in this function,
 * because we're unstoppable, so we have to be
 * called repeatedly from userland.
 */
void
parityops(struct vinum_ioctl_msg *data)
{
    int plexno;
    struct plex *plex;
    int size;                                               /* I/O transfer size, bytes */
    struct rangelock *lock;                                 /* lock on stripe */
    struct _ioctl_reply *reply;
    off_t pstripe;                                          /* pointer to our stripe counter */
    struct buf *pbp;
    off_t errorloc;                                         /* offset of parity error */
    enum parityop op;                                       /* operation to perform */

    plexno = data->index;
    op = data->op;
    pbp = NULL;
    reply = (struct _ioctl_reply *) data;
    reply->error = EAGAIN;                                  /* expect to repeat this call */
    plex = &PLEX[plexno];
    if (!isparity(plex)) {                                  /* not RAID-4 or RAID-5 */
        reply->error = EINVAL;
        return;
    } else if (plex->state < plex_flaky) {
        reply->error = EIO;
        strcpy(reply->msg, "Plex is not completely accessible\n");
        return;
    }
    pstripe = data->offset;
    size = imin(DEFAULT_REVIVE_BLOCKSIZE,                   /* one block at a time */
        plex->stripesize << DEV_BSHIFT);

    errorloc = 0;       /* avoid gcc warnings */
    pbp = parityrebuild(plex, pstripe, size, op, &lock, &errorloc); /* do the grunt work */
    if (pbp == NULL) {                                      /* no buffer space */
        reply->error = ENOMEM;
        return;                                             /* chicken out */
    }
    /*
     * Now we have a result in the data buffer of
     * the parity buffer header, which we have kept.
     * Decide what to do with it.
     */
    reply->msg[0] = '\0';                                   /* until shown otherwise */
    if ((pbp->b_flags & B_ERROR) == 0) {                    /* no error */
        if ((op == rebuildparity)
            || (op == rebuildandcheckparity)) {
            pbp->b_cmd = BUF_CMD_WRITE;
            pbp->b_resid = pbp->b_bcount;
            pbp->b_bio1.bio_done = biodone_sync;
            sdio(&pbp->b_bio1);                             /* write the parity block */
            biowait(&pbp->b_bio1, "drvwr");
        }
        if (((op == checkparity)
                || (op == rebuildandcheckparity))
            && (errorloc != -1)) {
            if (op == checkparity)
                reply->error = EIO;
            ksprintf(reply->msg,
                "Parity incorrect at offset 0x%llx\n",
                (long long)errorloc);
        }
        if (reply->error == EAGAIN) {                       /* still OK, */
            plex->checkblock = pstripe + (pbp->b_bcount >> DEV_BSHIFT); /* moved this much further down */
            if (plex->checkblock >= SD[plex->sdnos[0]].sectors) { /* finished */
                plex->checkblock = 0;
                reply->error = 0;
            }
        }
    }
    if (pbp->b_flags & B_ERROR)
        reply->error = pbp->b_error;
    Free(pbp->b_data);
    relpbuf(pbp, &vinum_conf.physbufs);
    unlockrange(plexno, lock);
}

/*
 * Rebuild a parity stripe.  Return pointer to
 * parity bp.  On return,
 *
 * 1.  The band is locked.  The caller must unlock
 *     the band and release the buffer header.
 *
 * 2.  All buffer headers except php have been
 *     released.  The caller must release pbp.
 *
 * 3.  For checkparity and rebuildandcheckparity,
 *     the parity is compared with the current
 *     parity block.  If it's different, the
 *     offset of the error is returned to
 *     errorloc.  The caller can set the value of
 *     the pointer to NULL if this is called for
 *     rebuilding parity.
 *
 * pstripe is the subdisk-relative base address of
 * the data to be reconstructed, size is the size
 * of the transfer in bytes.
 */
struct buf *
parityrebuild(struct plex *plex,
    vinum_off_t pstripe,
    int size,
    enum parityop op,
    struct rangelock **lockp,
    off_t * errorloc)
{
    int error;
    int sdno;
    u_int64_t stripe;                                       /* stripe number */
    int *parity_buf;                                        /* buffer address for current parity block */
    int *newparity_buf;                                     /* and for new parity block */
    int mysize;                                             /* I/O transfer size for this transfer */
    int isize;                                              /* mysize in ints */
    int i;
    int psd;                                                /* parity subdisk number */
    int newpsd;                                             /* and "subdisk number" of new parity */
    struct buf **bpp;                                       /* pointers to our bps */
    struct buf *pbp;                                        /* buffer header for parity stripe */
    int *sbuf;
    int bufcount;                                           /* number of buffers we need */

    stripe = pstripe / plex->stripesize;                    /* stripe number */
    psd = plex->subdisks - 1 - stripe % plex->subdisks;     /* parity subdisk for this stripe */
    parity_buf = NULL;                                      /* to keep the compiler happy */
    error = 0;

    /*
     * It's possible that the default transfer size
     * we chose is not a factor of the stripe size.
     * We *must* limit this operation to a single
     * stripe, at least for RAID-5 rebuild, since
     * the parity subdisk changes between stripes,
     * so in this case we need to perform a short
     * transfer.  Set variable mysize to reflect
     * this.
     */
    mysize = u64min(size, (plex->stripesize * (stripe + 1) - pstripe) << DEV_BSHIFT);
    isize = mysize / (sizeof(int));                         /* number of ints in the buffer */
    bufcount = plex->subdisks + 1;                          /* sd buffers plus result buffer */
    newpsd = plex->subdisks;
    bpp = (struct buf **) Malloc(bufcount * sizeof(struct buf *)); /* array of pointers to bps */

    /* First, build requests for all subdisks */
    for (sdno = 0; sdno < bufcount; sdno++) {               /* for each subdisk */
        if ((sdno != psd) || (op != rebuildparity)) {
            /* Get a buffer header and initialize it. */
            bpp[sdno] = getpbuf(&vinum_conf.physbufs);      /* Get a buffer */
            bpp[sdno]->b_data = Malloc(mysize);
            if (sdno == psd)
                parity_buf = (int *) bpp[sdno]->b_data;
            if (sdno == newpsd)                             /* the new one? */
                bpp[sdno]->b_bio1.bio_driver_info = SD[plex->sdnos[psd]].sd_dev; /* write back to the parity SD */
            else
                bpp[sdno]->b_bio1.bio_driver_info = SD[plex->sdnos[sdno]].sd_dev;       /* device number */
            KKASSERT(bpp[sdno]->b_bio1.bio_driver_info);
            bpp[sdno]->b_cmd = BUF_CMD_READ;        /* either way, read it */
            bpp[sdno]->b_bcount = mysize;
            bpp[sdno]->b_resid = bpp[sdno]->b_bcount;
            bpp[sdno]->b_bio1.bio_offset = (off_t)pstripe << DEV_BSHIFT;            /* transfer from here */
            bpp[sdno]->b_bio1.bio_done = biodone_sync;
        }
    }

    /* Initialize result buffer */
    pbp = bpp[newpsd];
    newparity_buf = (int *) bpp[newpsd]->b_data;
    bzero(newparity_buf, mysize);

    /*
     * Now lock the stripe with the first non-parity
     * bp as locking bp.
     */
    *lockp = lockrange(pstripe * plex->stripesize * (plex->subdisks - 1),
        bpp[psd ? 0 : 1],
        plex);

    /*
     * Then issue requests for all subdisks in
     * parallel.  Don't transfer the parity stripe
     * if we're rebuilding parity, unless we also
     * want to check it.
     */
    for (sdno = 0; sdno < plex->subdisks; sdno++) {         /* for each real subdisk */
        if ((sdno != psd) || (op != rebuildparity)) {
            sdio(&bpp[sdno]->b_bio1);
        }
    }

    /*
     * Next, wait for the requests to complete.
     * We wait in the order in which they were
     * issued, which isn't necessarily the order in
     * which they complete, but we don't have a
     * convenient way of doing the latter, and the
     * delay is minimal.
     */
    for (sdno = 0; sdno < plex->subdisks; sdno++) {         /* for each subdisk */
        if ((sdno != psd) || (op != rebuildparity)) {
            biowait(&bpp[sdno]->b_bio1, "drvio");
            if (bpp[sdno]->b_flags & B_ERROR)               /* can't read, */
                error = bpp[sdno]->b_error;
            else if (sdno != psd) {                         /* update parity */
                sbuf = (int *) bpp[sdno]->b_data;
                for (i = 0; i < isize; i++)
                    newparity_buf[i] ^= sbuf[i];            /* xor in the buffer */
            }
        }
        if (sdno != psd) {                                  /* release all bps except parity */
            Free(bpp[sdno]->b_data);
            relpbuf(bpp[sdno], &vinum_conf.physbufs);       /* give back our resources */
        }
    }

    /*
     * If we're checking, compare the calculated
     * and the read parity block.  If they're
     * different, return the plex-relative offset;
     * otherwise return -1.
     */
    if ((op == checkparity)
        || (op == rebuildandcheckparity)) {
        *errorloc = -1;                                     /* no error yet */
        for (i = 0; i < isize; i++) {
            if (parity_buf[i] != newparity_buf[i]) {
                *errorloc = (off_t) (pstripe << DEV_BSHIFT) * (plex->subdisks - 1)
                    + i * sizeof(int);
                break;
            }
        }
        Free(bpp[psd]->b_data);
        relpbuf(bpp[psd], &vinum_conf.physbufs);            /* give back our resources */
    }
    /* release our resources */
    Free(bpp);
    if (error) {
        pbp->b_flags |= B_ERROR;
        pbp->b_error = error;
    }
    return pbp;
}

/*
 * Initialize a subdisk by writing zeroes to the
 * complete address space.  If verify is set,
 * check each transfer for correctness.
 *
 * Each call to this function writes (and maybe
 * checks) a single block.
 */
int
initsd(int sdno, int verify)
{
    struct sd *sd;
    struct plex *plex;
    struct buf *bp;
    int error;
    int size;                                               /* size of init block, bytes */
    int verified;                                           /* set when we're happy with what we wrote */

    error = 0;
    sd = &SD[sdno];
    if (sd->plexno < 0)                                     /* no plex? */
        return EINVAL;
    plex = &PLEX[sd->plexno];                               /* point to plex */

    if (sd->init_blocksize == 0) {
        if (plex->stripesize != 0)                          /* we're striped, don't init more than */
            sd->init_blocksize = u64min(DEFAULT_REVIVE_BLOCKSIZE, /* one block at a time */
                plex->stripesize << DEV_BSHIFT);
        else
            sd->init_blocksize = DEFAULT_REVIVE_BLOCKSIZE;
    } else if (sd->init_blocksize > MAX_REVIVE_BLOCKSIZE)
        sd->init_blocksize = MAX_REVIVE_BLOCKSIZE;

    size = u64min(sd->init_blocksize >> DEV_BSHIFT, sd->sectors - sd->initialized) << DEV_BSHIFT;

    bp = getpbuf(&vinum_conf.physbufs);             /* Get a buffer */
    bp->b_data = Malloc(size);

    verified = 0;
    while (!verified) {                                     /* until we're happy with it, */
        bp->b_bcount = size;
        bp->b_resid = bp->b_bcount;
        bp->b_bio1.bio_offset = (off_t)sd->initialized << DEV_BSHIFT;               /* write it to here */
        bp->b_bio1.bio_driver_info = SD[sdno].sd_dev;
        bp->b_bio1.bio_done = biodone_sync;
        KKASSERT(bp->b_bio1.bio_driver_info);
        bzero(bp->b_data, bp->b_bcount);
        bp->b_cmd = BUF_CMD_WRITE;
        sdio(&bp->b_bio1);                  /* perform the I/O */
        biowait(&bp->b_bio1, "drvwr");
        if (bp->b_flags & B_ERROR)
            error = bp->b_error;
        if ((error == 0) && verify) {                       /* check that it got there */
            bp->b_bcount = size;
            bp->b_resid = bp->b_bcount;
            bp->b_bio1.bio_offset = (off_t)sd->initialized << DEV_BSHIFT;           /* read from here */
            bp->b_bio1.bio_driver_info = SD[sdno].sd_dev;
            bp->b_bio1.bio_done = biodone_sync;
            KKASSERT(bp->b_bio1.bio_driver_info);
            bp->b_cmd = BUF_CMD_READ;               /* read it back */
            sdio(&bp->b_bio1);
            biowait(&bp->b_bio1, "drvrd");
            /*
             * XXX Bug fix code.  This is hopefully no
             * longer needed (21 February 2000).
             */
            if (bp->b_flags & B_ERROR)
                error = bp->b_error;
            else if ((*bp->b_data != 0)             /* first word spammed */
            ||(bcmp(bp->b_data, &bp->b_data[1], bp->b_bcount - 1))) { /* or one of the others */
                kprintf("vinum: init error on %s, offset 0x%llx sectors\n",
                    sd->name,
                    (long long) sd->initialized);
                verified = 0;
            } else
                verified = 1;
        } else
            verified = 1;
    }
    Free(bp->b_data);
    relpbuf(bp, &vinum_conf.physbufs);
    if (error == 0) {                                       /* did it, */
        sd->initialized += size >> DEV_BSHIFT;              /* moved this much further down */
        if (sd->initialized >= sd->sectors) {               /* finished */
            sd->initialized = 0;
            set_sd_state(sdno, sd_initialized, setstate_force); /* bring the sd up */
            log(LOG_INFO, "vinum: %s is %s\n", sd->name, sd_state(sd->state));
            save_config();                                  /* and save the updated configuration */
        } else                                              /* more to go, */
            error = EAGAIN;                                 /* ya'll come back, see? */
    }
    return error;
}