ore.c

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/*
 * Copyright (C) 2005, 2006
 * Avishay Traeger ([email protected])
 * Copyright (C) 2008, 2009
 * Boaz Harrosh <[email protected]>
 *
 * This file is part of exofs.
 *
 * exofs is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation.  Since it is based on ext2, and the only
 * valid version of GPL for the Linux kernel is version 2, the only valid
 * version of GPL for exofs is version 2.
 *
 * exofs 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 for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with exofs; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

#include <linux/slab.h>
#include <linux/module.h>
#include <asm/div64.h>
#include <linux/lcm.h>

#include "ore_raid.h"

MODULE_AUTHOR("Boaz Harrosh <[email protected]>");
MODULE_DESCRIPTION("Objects Raid Engine ore.ko");
MODULE_LICENSE("GPL");

/* ore_verify_layout does a couple of things:
 * 1. Given a minimum number of needed parameters fixes up the rest of the
 *    members to be operatonals for the ore. The needed parameters are those
 *    that are defined by the pnfs-objects layout STD.
 * 2. Check to see if the current ore code actually supports these parameters
 *    for example stripe_unit must be a multple of the system PAGE_SIZE,
 *    and etc...
 * 3. Cache some havily used calculations that will be needed by users.
 */

enum { BIO_MAX_PAGES_KMALLOC =
        (PAGE_SIZE - sizeof(struct bio)) / sizeof(struct bio_vec),};

int ore_verify_layout(unsigned total_comps, struct ore_layout *layout)
{
    u64 stripe_length;

    switch (layout->raid_algorithm) {
    case PNFS_OSD_RAID_0:
        layout->parity = 0;
        break;
    case PNFS_OSD_RAID_5:
        layout->parity = 1;
        break;
    case PNFS_OSD_RAID_PQ:
    case PNFS_OSD_RAID_4:
    default:
        ORE_ERR("Only RAID_0/5 for now\n");
        return -EINVAL;
    }
    if (0 != (layout->stripe_unit & ~PAGE_MASK)) {
        ORE_ERR("Stripe Unit(0x%llx)"
              " must be Multples of PAGE_SIZE(0x%lx)\n",
              _LLU(layout->stripe_unit), PAGE_SIZE);
        return -EINVAL;
    }
    if (layout->group_width) {
        if (!layout->group_depth) {
            ORE_ERR("group_depth == 0 && group_width != 0\n");
            return -EINVAL;
        }
        if (total_comps < (layout->group_width * layout->mirrors_p1)) {
            ORE_ERR("Data Map wrong, "
                "numdevs=%d < group_width=%d * mirrors=%d\n",
                total_comps, layout->group_width,
                layout->mirrors_p1);
            return -EINVAL;
        }
        layout->group_count = total_comps / layout->mirrors_p1 /
                        layout->group_width;
    } else {
        if (layout->group_depth) {
            printk(KERN_NOTICE "Warning: group_depth ignored "
                "group_width == 0 && group_depth == %lld\n",
                _LLU(layout->group_depth));
        }
        layout->group_width = total_comps / layout->mirrors_p1;
        layout->group_depth = -1;
        layout->group_count = 1;
    }

    stripe_length = (u64)layout->group_width * layout->stripe_unit;
    if (stripe_length >= (1ULL << 32)) {
        ORE_ERR("Stripe_length(0x%llx) >= 32bit is not supported\n",
            _LLU(stripe_length));
        return -EINVAL;
    }

    layout->max_io_length =
        (BIO_MAX_PAGES_KMALLOC * PAGE_SIZE - layout->stripe_unit) *
                            layout->group_width;
    if (layout->parity) {
        unsigned stripe_length =
                (layout->group_width - layout->parity) *
                layout->stripe_unit;

        layout->max_io_length /= stripe_length;
        layout->max_io_length *= stripe_length;
    }
    return 0;
}
EXPORT_SYMBOL(ore_verify_layout);

static u8 *_ios_cred(struct ore_io_state *ios, unsigned index)
{
    return ios->oc->comps[index & ios->oc->single_comp].cred;
}

static struct osd_obj_id *_ios_obj(struct ore_io_state *ios, unsigned index)
{
    return &ios->oc->comps[index & ios->oc->single_comp].obj;
}

static struct osd_dev *_ios_od(struct ore_io_state *ios, unsigned index)
{
    ORE_DBGMSG2("oc->first_dev=%d oc->numdevs=%d i=%d oc->ods=%p\n",
            ios->oc->first_dev, ios->oc->numdevs, index,
            ios->oc->ods);

    return ore_comp_dev(ios->oc, index);
}

int  _ore_get_io_state(struct ore_layout *layout,
            struct ore_components *oc, unsigned numdevs,
            unsigned sgs_per_dev, unsigned num_par_pages,
            struct ore_io_state **pios)
{
    struct ore_io_state *ios;
    struct page **pages;
    struct osd_sg_entry *sgilist;
    struct __alloc_all_io_state {
        struct ore_io_state ios;
        struct ore_per_dev_state per_dev[numdevs];
        union {
            struct osd_sg_entry sglist[sgs_per_dev * numdevs];
            struct page *pages[num_par_pages];
        };
    } *_aios;

    if (likely(sizeof(*_aios) <= PAGE_SIZE)) {
        _aios = kzalloc(sizeof(*_aios), GFP_KERNEL);
        if (unlikely(!_aios)) {
            ORE_DBGMSG("Failed kzalloc bytes=%zd\n",
                   sizeof(*_aios));
            *pios = NULL;
            return -ENOMEM;
        }
        pages = num_par_pages ? _aios->pages : NULL;
        sgilist = sgs_per_dev ? _aios->sglist : NULL;
        ios = &_aios->ios;
    } else {
        struct __alloc_small_io_state {
            struct ore_io_state ios;
            struct ore_per_dev_state per_dev[numdevs];
        } *_aio_small;
        union __extra_part {
            struct osd_sg_entry sglist[sgs_per_dev * numdevs];
            struct page *pages[num_par_pages];
        } *extra_part;

        _aio_small = kzalloc(sizeof(*_aio_small), GFP_KERNEL);
        if (unlikely(!_aio_small)) {
            ORE_DBGMSG("Failed alloc first part bytes=%zd\n",
                   sizeof(*_aio_small));
            *pios = NULL;
            return -ENOMEM;
        }
        extra_part = kzalloc(sizeof(*extra_part), GFP_KERNEL);
        if (unlikely(!extra_part)) {
            ORE_DBGMSG("Failed alloc second part bytes=%zd\n",
                   sizeof(*extra_part));
            kfree(_aio_small);
            *pios = NULL;
            return -ENOMEM;
        }

        pages = num_par_pages ? extra_part->pages : NULL;
        sgilist = sgs_per_dev ? extra_part->sglist : NULL;
        /* In this case the per_dev[0].sgilist holds the pointer to
         * be freed
         */
        ios = &_aio_small->ios;
        ios->extra_part_alloc = true;
    }

    if (pages) {
        ios->parity_pages = pages;
        ios->max_par_pages = num_par_pages;
    }
    if (sgilist) {
        unsigned d;

        for (d = 0; d < numdevs; ++d) {
            ios->per_dev[d].sglist = sgilist;
            sgilist += sgs_per_dev;
        }
        ios->sgs_per_dev = sgs_per_dev;
    }

    ios->layout = layout;
    ios->oc = oc;
    *pios = ios;
    return 0;
}

/* Allocate an io_state for only a single group of devices
 *
 * If a user needs to call ore_read/write() this version must be used becase it
 * allocates extra stuff for striping and raid.
 * The ore might decide to only IO less then @length bytes do to alignmets
 * and constrains as follows:
 * - The IO cannot cross group boundary.
 * - In raid5/6 The end of the IO must align at end of a stripe eg.
 *   (@offset + @length) % strip_size == 0. Or the complete range is within a
 *   single stripe.
 * - Memory condition only permitted a shorter IO. (A user can use @length=~0
 *   And check the returned ios->length for max_io_size.)
 *
 * The caller must check returned ios->length (and/or ios->nr_pages) and
 * re-issue these pages that fall outside of ios->length
 */
int  ore_get_rw_state(struct ore_layout *layout, struct ore_components *oc,
              bool is_reading, u64 offset, u64 length,
              struct ore_io_state **pios)
{
    struct ore_io_state *ios;
    unsigned numdevs = layout->group_width * layout->mirrors_p1;
    unsigned sgs_per_dev = 0, max_par_pages = 0;
    int ret;

    if (layout->parity && length) {
        unsigned data_devs = layout->group_width - layout->parity;
        unsigned stripe_size = layout->stripe_unit * data_devs;
        unsigned pages_in_unit = layout->stripe_unit / PAGE_SIZE;
        u32 remainder;
        u64 num_stripes;
        u64 num_raid_units;

        num_stripes = div_u64_rem(length, stripe_size, &remainder);
        if (remainder)
            ++num_stripes;

        num_raid_units =  num_stripes * layout->parity;

        if (is_reading) {
            /* For reads add per_dev sglist array */
            /* TODO: Raid 6 we need twice more. Actually:
            *         num_stripes / LCMdP(W,P);
            *         if (W%P != 0) num_stripes *= parity;
            */

            /* first/last seg is split */
            num_raid_units += layout->group_width;
            sgs_per_dev = div_u64(num_raid_units, data_devs) + 2;
        } else {
            /* For Writes add parity pages array. */
            max_par_pages = num_raid_units * pages_in_unit *
                        sizeof(struct page *);
        }
    }

    ret = _ore_get_io_state(layout, oc, numdevs, sgs_per_dev, max_par_pages,
                pios);
    if (unlikely(ret))
        return ret;

    ios = *pios;
    ios->reading = is_reading;
    ios->offset = offset;

    if (length) {
        ore_calc_stripe_info(layout, offset, length, &ios->si);
        ios->length = ios->si.length;
        ios->nr_pages = (ios->length + PAGE_SIZE - 1) / PAGE_SIZE;
        if (layout->parity)
            _ore_post_alloc_raid_stuff(ios);
    }

    return 0;
}
EXPORT_SYMBOL(ore_get_rw_state);

/* Allocate an io_state for all the devices in the comps array
 *
 * This version of io_state allocation is used mostly by create/remove
 * and trunc where we currently need all the devices. The only wastful
 * bit is the read/write_attributes with no IO. Those sites should
 * be converted to use ore_get_rw_state() with length=0
 */
int  ore_get_io_state(struct ore_layout *layout, struct ore_components *oc,
              struct ore_io_state **pios)
{
    return _ore_get_io_state(layout, oc, oc->numdevs, 0, 0, pios);
}
EXPORT_SYMBOL(ore_get_io_state);

void ore_put_io_state(struct ore_io_state *ios)
{
    if (ios) {
        unsigned i;

        for (i = 0; i < ios->numdevs; i++) {
            struct ore_per_dev_state *per_dev = &ios->per_dev[i];

            if (per_dev->or)
                osd_end_request(per_dev->or);
            if (per_dev->bio)
                bio_put(per_dev->bio);
        }

        _ore_free_raid_stuff(ios);
        kfree(ios);
    }
}
EXPORT_SYMBOL(ore_put_io_state);

static void _sync_done(struct ore_io_state *ios, void *p)
{
    struct completion *waiting = p;

    complete(waiting);
}

static void _last_io(struct kref *kref)
{
    struct ore_io_state *ios = container_of(
                    kref, struct ore_io_state, kref);

    ios->done(ios, ios->private);
}

static void _done_io(struct osd_request *or, void *p)
{
    struct ore_io_state *ios = p;

    kref_put(&ios->kref, _last_io);
}

int ore_io_execute(struct ore_io_state *ios)
{
    DECLARE_COMPLETION_ONSTACK(wait);
    bool sync = (ios->done == NULL);
    int i, ret;

    if (sync) {
        ios->done = _sync_done;
        ios->private = &wait;
    }

    for (i = 0; i < ios->numdevs; i++) {
        struct osd_request *or = ios->per_dev[i].or;
        if (unlikely(!or))
            continue;

        ret = osd_finalize_request(or, 0, _ios_cred(ios, i), NULL);
        if (unlikely(ret)) {
            ORE_DBGMSG("Failed to osd_finalize_request() => %d\n",
                     ret);
            return ret;
        }
    }

    kref_init(&ios->kref);

    for (i = 0; i < ios->numdevs; i++) {
        struct osd_request *or = ios->per_dev[i].or;
        if (unlikely(!or))
            continue;

        kref_get(&ios->kref);
        osd_execute_request_async(or, _done_io, ios);
    }

    kref_put(&ios->kref, _last_io);
    ret = 0;

    if (sync) {
        wait_for_completion(&wait);
        ret = ore_check_io(ios, NULL);
    }
    return ret;
}

static void _clear_bio(struct bio *bio)
{
    struct bio_vec *bv;
    unsigned i;

    __bio_for_each_segment(bv, bio, i, 0) {
        unsigned this_count = bv->bv_len;

        if (likely(PAGE_SIZE == this_count))
            clear_highpage(bv->bv_page);
        else
            zero_user(bv->bv_page, bv->bv_offset, this_count);
    }
}

int ore_check_io(struct ore_io_state *ios, ore_on_dev_error on_dev_error)
{
    enum osd_err_priority acumulated_osd_err = 0;
    int acumulated_lin_err = 0;
    int i;

    for (i = 0; i < ios->numdevs; i++) {
        struct osd_sense_info osi;
        struct ore_per_dev_state *per_dev = &ios->per_dev[i];
        struct osd_request *or = per_dev->or;
        int ret;

        if (unlikely(!or))
            continue;

        ret = osd_req_decode_sense(or, &osi);
        if (likely(!ret))
            continue;

        if (OSD_ERR_PRI_CLEAR_PAGES == osi.osd_err_pri) {
            /* start read offset passed endof file */
            _clear_bio(per_dev->bio);
            ORE_DBGMSG("start read offset passed end of file "
                "offset=0x%llx, length=0x%llx\n",
                _LLU(per_dev->offset),
                _LLU(per_dev->length));

            continue; /* we recovered */
        }

        if (on_dev_error) {
            u64 residual = ios->reading ?
                    or->in.residual : or->out.residual;
            u64 offset = (ios->offset + ios->length) - residual;
            unsigned dev = per_dev->dev - ios->oc->first_dev;
            struct ore_dev *od = ios->oc->ods[dev];

            on_dev_error(ios, od, dev, osi.osd_err_pri,
                     offset, residual);
        }
        if (osi.osd_err_pri >= acumulated_osd_err) {
            acumulated_osd_err = osi.osd_err_pri;
            acumulated_lin_err = ret;
        }
    }

    return acumulated_lin_err;
}
EXPORT_SYMBOL(ore_check_io);

/*
 * L - logical offset into the file
 *
 * D - number of Data devices
 *  D = group_width - parity
 *
 * U - The number of bytes in a stripe within a group
 *  U =  stripe_unit * D
 *
 * T - The number of bytes striped within a group of component objects
 *     (before advancing to the next group)
 *  T = U * group_depth
 *
 * S - The number of bytes striped across all component objects
 *     before the pattern repeats
 *  S = T * group_count
 *
 * M - The "major" (i.e., across all components) cycle number
 *  M = L / S
 *
 * G - Counts the groups from the beginning of the major cycle
 *  G = (L - (M * S)) / T   [or (L % S) / T]
 *
 * H - The byte offset within the group
 *  H = (L - (M * S)) % T   [or (L % S) % T]
 *
 * N - The "minor" (i.e., across the group) stripe number
 *  N = H / U
 *
 * C - The component index coresponding to L
 *
 *  C = (H - (N * U)) / stripe_unit + G * D
 *  [or (L % U) / stripe_unit + G * D]
 *
 * O - The component offset coresponding to L
 *  O = L % stripe_unit + N * stripe_unit + M * group_depth * stripe_unit
 *
 * LCMdP – Parity cycle: Lowest Common Multiple of group_width, parity
 *          divide by parity
 *  LCMdP = lcm(group_width, parity) / parity
 *
 * R - The parity Rotation stripe
 *     (Note parity cycle always starts at a group's boundary)
 *  R = N % LCMdP
 *
 * I = the first parity device index
 *  I = (group_width + group_width - R*parity - parity) % group_width
 *
 * Craid - The component index Rotated
 *  Craid = (group_width + C - R*parity) % group_width
 *      (We add the group_width to avoid negative numbers modulo math)
 */
void ore_calc_stripe_info(struct ore_layout *layout, u64 file_offset,
              u64 length, struct ore_striping_info *si)
{
    u32 stripe_unit = layout->stripe_unit;
    u32 group_width = layout->group_width;
    u64 group_depth = layout->group_depth;
    u32 parity      = layout->parity;

    u32 D = group_width - parity;
    u32 U = D * stripe_unit;
    u64 T = U * group_depth;
    u64 S = T * layout->group_count;
    u64 M = div64_u64(file_offset, S);

    /*
    G = (L - (M * S)) / T
    H = (L - (M * S)) % T
    */
    u64 LmodS = file_offset - M * S;
    u32 G = div64_u64(LmodS, T);
    u64 H = LmodS - G * T;

    u32 N = div_u64(H, U);

    /* "H - (N * U)" is just "H % U" so it's bound to u32 */
    u32 C = (u32)(H - (N * U)) / stripe_unit + G * group_width;

    div_u64_rem(file_offset, stripe_unit, &si->unit_off);

    si->obj_offset = si->unit_off + (N * stripe_unit) +
                  (M * group_depth * stripe_unit);

    if (parity) {
        u32 LCMdP = lcm(group_width, parity) / parity;
        /* R     = N % LCMdP; */
        u32 RxP   = (N % LCMdP) * parity;
        u32 first_dev = C - C % group_width;

        si->par_dev = (group_width + group_width - parity - RxP) %
                  group_width + first_dev;
        si->dev = (group_width + C - RxP) % group_width + first_dev;
        si->bytes_in_stripe = U;
        si->first_stripe_start = M * S + G * T + N * U;
    } else {
        /* Make the math correct see _prepare_one_group */
        si->par_dev = group_width;
        si->dev = C;
    }

    si->dev *= layout->mirrors_p1;
    si->par_dev *= layout->mirrors_p1;
    si->offset = file_offset;
    si->length = T - H;
    if (si->length > length)
        si->length = length;
    si->M = M;
}
EXPORT_SYMBOL(ore_calc_stripe_info);

int _ore_add_stripe_unit(struct ore_io_state *ios,  unsigned *cur_pg,
             unsigned pgbase, struct page **pages,
             struct ore_per_dev_state *per_dev, int cur_len)
{
    unsigned pg = *cur_pg;
    struct request_queue *q =
            osd_request_queue(_ios_od(ios, per_dev->dev));
    unsigned len = cur_len;
    int ret;

    if (per_dev->bio == NULL) {
        unsigned pages_in_stripe = ios->layout->group_width *
                    (ios->layout->stripe_unit / PAGE_SIZE);
        unsigned nr_pages = ios->nr_pages * ios->layout->group_width /
                    (ios->layout->group_width -
                     ios->layout->parity);
        unsigned bio_size = (nr_pages + pages_in_stripe) /
                    ios->layout->group_width;

        per_dev->bio = bio_kmalloc(GFP_KERNEL, bio_size);
        if (unlikely(!per_dev->bio)) {
            ORE_DBGMSG("Failed to allocate BIO size=%u\n",
                     bio_size);
            ret = -ENOMEM;
            goto out;
        }
    }

    while (cur_len > 0) {
        unsigned pglen = min_t(unsigned, PAGE_SIZE - pgbase, cur_len);
        unsigned added_len;

        cur_len -= pglen;

        added_len = bio_add_pc_page(q, per_dev->bio, pages[pg],
                        pglen, pgbase);
        if (unlikely(pglen != added_len)) {
            ORE_DBGMSG("Failed bio_add_pc_page bi_vcnt=%u\n",
                   per_dev->bio->bi_vcnt);
            ret = -ENOMEM;
            goto out;
        }
        _add_stripe_page(ios->sp2d, &ios->si, pages[pg]);

        pgbase = 0;
        ++pg;
    }
    BUG_ON(cur_len);

    per_dev->length += len;
    *cur_pg = pg;
    ret = 0;
out:    /* we fail the complete unit on an error eg don't advance
     * per_dev->length and cur_pg. This means that we might have a bigger
     * bio than the CDB requested length (per_dev->length). That's fine
     * only the oposite is fatal.
     */
    return ret;
}

static int _prepare_for_striping(struct ore_io_state *ios)
{
    struct ore_striping_info *si = &ios->si;
    unsigned stripe_unit = ios->layout->stripe_unit;
    unsigned mirrors_p1 = ios->layout->mirrors_p1;
    unsigned group_width = ios->layout->group_width;
    unsigned devs_in_group = group_width * mirrors_p1;
    unsigned dev = si->dev;
    unsigned first_dev = dev - (dev % devs_in_group);
    unsigned dev_order;
    unsigned cur_pg = ios->pages_consumed;
    u64 length = ios->length;
    int ret = 0;

    if (!ios->pages) {
        ios->numdevs = ios->layout->mirrors_p1;
        return 0;
    }

    BUG_ON(length > si->length);

    dev_order = _dev_order(devs_in_group, mirrors_p1, si->par_dev, dev);
    si->cur_comp = dev_order;
    si->cur_pg = si->unit_off / PAGE_SIZE;

    while (length) {
        unsigned comp = dev - first_dev;
        struct ore_per_dev_state *per_dev = &ios->per_dev[comp];
        unsigned cur_len, page_off = 0;

        if (!per_dev->length) {
            per_dev->dev = dev;
            if (dev == si->dev) {
                WARN_ON(dev == si->par_dev);
                per_dev->offset = si->obj_offset;
                cur_len = stripe_unit - si->unit_off;
                page_off = si->unit_off & ~PAGE_MASK;
                BUG_ON(page_off && (page_off != ios->pgbase));
            } else {
                if (si->cur_comp > dev_order)
                    per_dev->offset =
                        si->obj_offset - si->unit_off;
                else /* si->cur_comp < dev_order */
                    per_dev->offset =
                        si->obj_offset + stripe_unit -
                                   si->unit_off;
                cur_len = stripe_unit;
            }
        } else {
            cur_len = stripe_unit;
        }
        if (cur_len >= length)
            cur_len = length;

        ret = _ore_add_stripe_unit(ios, &cur_pg, page_off, ios->pages,
                       per_dev, cur_len);
        if (unlikely(ret))
            goto out;

        dev += mirrors_p1;
        dev = (dev % devs_in_group) + first_dev;

        length -= cur_len;

        si->cur_comp = (si->cur_comp + 1) % group_width;
        if (unlikely((dev == si->par_dev) || (!length && ios->sp2d))) {
            if (!length && ios->sp2d) {
                /* If we are writing and this is the very last
                 * stripe. then operate on parity dev.
                 */
                dev = si->par_dev;
            }
            if (ios->sp2d)
                /* In writes cur_len just means if it's the
                 * last one. See _ore_add_parity_unit.
                 */
                cur_len = length;
            per_dev = &ios->per_dev[dev - first_dev];
            if (!per_dev->length) {
                /* Only/always the parity unit of the first
                 * stripe will be empty. So this is a chance to
                 * initialize the per_dev info.
                 */
                per_dev->dev = dev;
                per_dev->offset = si->obj_offset - si->unit_off;
            }

            ret = _ore_add_parity_unit(ios, si, per_dev, cur_len);
            if (unlikely(ret))
                    goto out;

            /* Rotate next par_dev backwards with wraping */
            si->par_dev = (devs_in_group + si->par_dev -
                       ios->layout->parity * mirrors_p1) %
                      devs_in_group + first_dev;
            /* Next stripe, start fresh */
            si->cur_comp = 0;
            si->cur_pg = 0;
        }
    }
out:
    ios->numdevs = devs_in_group;
    ios->pages_consumed = cur_pg;
    return ret;
}

int ore_create(struct ore_io_state *ios)
{
    int i, ret;

    for (i = 0; i < ios->oc->numdevs; i++) {
        struct osd_request *or;

        or = osd_start_request(_ios_od(ios, i), GFP_KERNEL);
        if (unlikely(!or)) {
            ORE_ERR("%s: osd_start_request failed\n", __func__);
            ret = -ENOMEM;
            goto out;
        }
        ios->per_dev[i].or = or;
        ios->numdevs++;

        osd_req_create_object(or, _ios_obj(ios, i));
    }
    ret = ore_io_execute(ios);

out:
    return ret;
}
EXPORT_SYMBOL(ore_create);

int ore_remove(struct ore_io_state *ios)
{
    int i, ret;

    for (i = 0; i < ios->oc->numdevs; i++) {
        struct osd_request *or;

        or = osd_start_request(_ios_od(ios, i), GFP_KERNEL);
        if (unlikely(!or)) {
            ORE_ERR("%s: osd_start_request failed\n", __func__);
            ret = -ENOMEM;
            goto out;
        }
        ios->per_dev[i].or = or;
        ios->numdevs++;

        osd_req_remove_object(or, _ios_obj(ios, i));
    }
    ret = ore_io_execute(ios);

out:
    return ret;
}
EXPORT_SYMBOL(ore_remove);

static int _write_mirror(struct ore_io_state *ios, int cur_comp)
{
    struct ore_per_dev_state *master_dev = &ios->per_dev[cur_comp];
    unsigned dev = ios->per_dev[cur_comp].dev;
    unsigned last_comp = cur_comp + ios->layout->mirrors_p1;
    int ret = 0;

    if (ios->pages && !master_dev->length)
        return 0; /* Just an empty slot */

    for (; cur_comp < last_comp; ++cur_comp, ++dev) {
        struct ore_per_dev_state *per_dev = &ios->per_dev[cur_comp];
        struct osd_request *or;

        or = osd_start_request(_ios_od(ios, dev), GFP_KERNEL);
        if (unlikely(!or)) {
            ORE_ERR("%s: osd_start_request failed\n", __func__);
            ret = -ENOMEM;
            goto out;
        }
        per_dev->or = or;

        if (ios->pages) {
            struct bio *bio;

            if (per_dev != master_dev) {
                bio = bio_clone_kmalloc(master_dev->bio,
                            GFP_KERNEL);
                if (unlikely(!bio)) {
                    ORE_DBGMSG(
                          "Failed to allocate BIO size=%u\n",
                          master_dev->bio->bi_max_vecs);
                    ret = -ENOMEM;
                    goto out;
                }

                bio->bi_bdev = NULL;
                bio->bi_next = NULL;
                per_dev->offset = master_dev->offset;
                per_dev->length = master_dev->length;
                per_dev->bio =  bio;
                per_dev->dev = dev;
            } else {
                bio = master_dev->bio;
                /* FIXME: bio_set_dir() */
                bio->bi_rw |= REQ_WRITE;
            }

            osd_req_write(or, _ios_obj(ios, cur_comp),
                      per_dev->offset, bio, per_dev->length);
            ORE_DBGMSG("write(0x%llx) offset=0x%llx "
                      "length=0x%llx dev=%d\n",
                     _LLU(_ios_obj(ios, cur_comp)->id),
                     _LLU(per_dev->offset),
                     _LLU(per_dev->length), dev);
        } else if (ios->kern_buff) {
            per_dev->offset = ios->si.obj_offset;
            per_dev->dev = ios->si.dev + dev;

            /* no cross device without page array */
            BUG_ON((ios->layout->group_width > 1) &&
                   (ios->si.unit_off + ios->length >
                ios->layout->stripe_unit));

            ret = osd_req_write_kern(or, _ios_obj(ios, cur_comp),
                         per_dev->offset,
                         ios->kern_buff, ios->length);
            if (unlikely(ret))
                goto out;
            ORE_DBGMSG2("write_kern(0x%llx) offset=0x%llx "
                      "length=0x%llx dev=%d\n",
                     _LLU(_ios_obj(ios, cur_comp)->id),
                     _LLU(per_dev->offset),
                     _LLU(ios->length), per_dev->dev);
        } else {
            osd_req_set_attributes(or, _ios_obj(ios, cur_comp));
            ORE_DBGMSG2("obj(0x%llx) set_attributes=%d dev=%d\n",
                     _LLU(_ios_obj(ios, cur_comp)->id),
                     ios->out_attr_len, dev);
        }

        if (ios->out_attr)
            osd_req_add_set_attr_list(or, ios->out_attr,
                          ios->out_attr_len);

        if (ios->in_attr)
            osd_req_add_get_attr_list(or, ios->in_attr,
                          ios->in_attr_len);
    }

out:
    return ret;
}

int ore_write(struct ore_io_state *ios)
{
    int i;
    int ret;

    if (unlikely(ios->sp2d && !ios->r4w)) {
        /* A library is attempting a RAID-write without providing
         * a pages lock interface.
         */
        WARN_ON_ONCE(1);
        return -ENOTSUPP;
    }

    ret = _prepare_for_striping(ios);
    if (unlikely(ret))
        return ret;

    for (i = 0; i < ios->numdevs; i += ios->layout->mirrors_p1) {
        ret = _write_mirror(ios, i);
        if (unlikely(ret))
            return ret;
    }

    ret = ore_io_execute(ios);
    return ret;
}
EXPORT_SYMBOL(ore_write);

int _ore_read_mirror(struct ore_io_state *ios, unsigned cur_comp)
{
    struct osd_request *or;
    struct ore_per_dev_state *per_dev = &ios->per_dev[cur_comp];
    struct osd_obj_id *obj = _ios_obj(ios, cur_comp);
    unsigned first_dev = (unsigned)obj->id;

    if (ios->pages && !per_dev->length)
        return 0; /* Just an empty slot */

    first_dev = per_dev->dev + first_dev % ios->layout->mirrors_p1;
    or = osd_start_request(_ios_od(ios, first_dev), GFP_KERNEL);
    if (unlikely(!or)) {
        ORE_ERR("%s: osd_start_request failed\n", __func__);
        return -ENOMEM;
    }
    per_dev->or = or;

    if (ios->pages) {
        if (per_dev->cur_sg) {
            /* finalize the last sg_entry */
            _ore_add_sg_seg(per_dev, 0, false);
            if (unlikely(!per_dev->cur_sg))
                return 0; /* Skip parity only device */

            osd_req_read_sg(or, obj, per_dev->bio,
                    per_dev->sglist, per_dev->cur_sg);
        } else {
            /* The no raid case */
            osd_req_read(or, obj, per_dev->offset,
                     per_dev->bio, per_dev->length);
        }

        ORE_DBGMSG("read(0x%llx) offset=0x%llx length=0x%llx"
                 " dev=%d sg_len=%d\n", _LLU(obj->id),
                 _LLU(per_dev->offset), _LLU(per_dev->length),
                 first_dev, per_dev->cur_sg);
    } else {
        BUG_ON(ios->kern_buff);

        osd_req_get_attributes(or, obj);
        ORE_DBGMSG2("obj(0x%llx) get_attributes=%d dev=%d\n",
                  _LLU(obj->id),
                  ios->in_attr_len, first_dev);
    }
    if (ios->out_attr)
        osd_req_add_set_attr_list(or, ios->out_attr, ios->out_attr_len);

    if (ios->in_attr)
        osd_req_add_get_attr_list(or, ios->in_attr, ios->in_attr_len);

    return 0;
}

int ore_read(struct ore_io_state *ios)
{
    int i;
    int ret;

    ret = _prepare_for_striping(ios);
    if (unlikely(ret))
        return ret;

    for (i = 0; i < ios->numdevs; i += ios->layout->mirrors_p1) {
        ret = _ore_read_mirror(ios, i);
        if (unlikely(ret))
            return ret;
    }

    ret = ore_io_execute(ios);
    return ret;
}
EXPORT_SYMBOL(ore_read);

int extract_attr_from_ios(struct ore_io_state *ios, struct osd_attr *attr)
{
    struct osd_attr cur_attr = {.attr_page = 0}; /* start with zeros */
    void *iter = NULL;
    int nelem;

    do {
        nelem = 1;
        osd_req_decode_get_attr_list(ios->per_dev[0].or,
                         &cur_attr, &nelem, &iter);
        if ((cur_attr.attr_page == attr->attr_page) &&
            (cur_attr.attr_id == attr->attr_id)) {
            attr->len = cur_attr.len;
            attr->val_ptr = cur_attr.val_ptr;
            return 0;
        }
    } while (iter);

    return -EIO;
}
EXPORT_SYMBOL(extract_attr_from_ios);

static int _truncate_mirrors(struct ore_io_state *ios, unsigned cur_comp,
                 struct osd_attr *attr)
{
    int last_comp = cur_comp + ios->layout->mirrors_p1;

    for (; cur_comp < last_comp; ++cur_comp) {
        struct ore_per_dev_state *per_dev = &ios->per_dev[cur_comp];
        struct osd_request *or;

        or = osd_start_request(_ios_od(ios, cur_comp), GFP_KERNEL);
        if (unlikely(!or)) {
            ORE_ERR("%s: osd_start_request failed\n", __func__);
            return -ENOMEM;
        }
        per_dev->or = or;

        osd_req_set_attributes(or, _ios_obj(ios, cur_comp));
        osd_req_add_set_attr_list(or, attr, 1);
    }

    return 0;
}

struct _trunc_info {
    struct ore_striping_info si;
    u64 prev_group_obj_off;
    u64 next_group_obj_off;

    unsigned first_group_dev;
    unsigned nex_group_dev;
};

static void _calc_trunk_info(struct ore_layout *layout, u64 file_offset,
                 struct _trunc_info *ti)
{
    unsigned stripe_unit = layout->stripe_unit;

    ore_calc_stripe_info(layout, file_offset, 0, &ti->si);

    ti->prev_group_obj_off = ti->si.M * stripe_unit;
    ti->next_group_obj_off = ti->si.M ? (ti->si.M - 1) * stripe_unit : 0;

    ti->first_group_dev = ti->si.dev - (ti->si.dev % layout->group_width);
    ti->nex_group_dev = ti->first_group_dev + layout->group_width;
}

int ore_truncate(struct ore_layout *layout, struct ore_components *oc,
           u64 size)
{
    struct ore_io_state *ios;
    struct exofs_trunc_attr {
        struct osd_attr attr;
        __be64 newsize;
    } *size_attrs;
    struct _trunc_info ti;
    int i, ret;

    ret = ore_get_io_state(layout, oc, &ios);
    if (unlikely(ret))
        return ret;

    _calc_trunk_info(ios->layout, size, &ti);

    size_attrs = kcalloc(ios->oc->numdevs, sizeof(*size_attrs),
                 GFP_KERNEL);
    if (unlikely(!size_attrs)) {
        ret = -ENOMEM;
        goto out;
    }

    ios->numdevs = ios->oc->numdevs;

    for (i = 0; i < ios->numdevs; ++i) {
        struct exofs_trunc_attr *size_attr = &size_attrs[i];
        u64 obj_size;

        if (i < ti.first_group_dev)
            obj_size = ti.prev_group_obj_off;
        else if (i >= ti.nex_group_dev)
            obj_size = ti.next_group_obj_off;
        else if (i < ti.si.dev) /* dev within this group */
            obj_size = ti.si.obj_offset +
                      ios->layout->stripe_unit - ti.si.unit_off;
        else if (i == ti.si.dev)
            obj_size = ti.si.obj_offset;
        else /* i > ti.dev */
            obj_size = ti.si.obj_offset - ti.si.unit_off;

        size_attr->newsize = cpu_to_be64(obj_size);
        size_attr->attr = g_attr_logical_length;
        size_attr->attr.val_ptr = &size_attr->newsize;

        ORE_DBGMSG("trunc(0x%llx) obj_offset=0x%llx dev=%d\n",
                 _LLU(oc->comps->obj.id), _LLU(obj_size), i);
        ret = _truncate_mirrors(ios, i * ios->layout->mirrors_p1,
                    &size_attr->attr);
        if (unlikely(ret))
            goto out;
    }
    ret = ore_io_execute(ios);

out:
    kfree(size_attrs);
    ore_put_io_state(ios);
    return ret;
}
EXPORT_SYMBOL(ore_truncate);

const struct osd_attr g_attr_logical_length = ATTR_DEF(
    OSD_APAGE_OBJECT_INFORMATION, OSD_ATTR_OI_LOGICAL_LENGTH, 8);
EXPORT_SYMBOL(g_attr_logical_length);