Merge commit 'v3.1-rc1' into imx-fixes

[mirror_ubuntu-artful-kernel.git] / fs / nfs / objlayout / objio_osd.c

/*
 *  pNFS Objects layout implementation over open-osd initiator library
 *
 *  Copyright (C) 2009 Panasas Inc. [year of first publication]
 *  All rights reserved.
 *
 *  Benny Halevy <bhalevy@panasas.com>
 *  Boaz Harrosh <bharrosh@panasas.com>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2
 *  See the file COPYING included with this distribution for more details.
 *
 *  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 Panasas 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 REGENTS 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 <linux/module.h>
#include <scsi/osd_initiator.h>

#include "objlayout.h"

#define NFSDBG_FACILITY         NFSDBG_PNFS_LD

#define _LLU(x) ((unsigned long long)x)

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

struct objio_dev_ent {
        struct nfs4_deviceid_node id_node;
        struct osd_dev *od;
};

static void
objio_free_deviceid_node(struct nfs4_deviceid_node *d)
{
        struct objio_dev_ent *de = container_of(d, struct objio_dev_ent, id_node);

        dprintk("%s: free od=%p\n", __func__, de->od);
        osduld_put_device(de->od);
        kfree(de);
}

static struct objio_dev_ent *_dev_list_find(const struct nfs_server *nfss,
        const struct nfs4_deviceid *d_id)
{
        struct nfs4_deviceid_node *d;
        struct objio_dev_ent *de;

        d = nfs4_find_get_deviceid(nfss->pnfs_curr_ld, nfss->nfs_client, d_id);
        if (!d)
                return NULL;

        de = container_of(d, struct objio_dev_ent, id_node);
        return de;
}

static struct objio_dev_ent *
_dev_list_add(const struct nfs_server *nfss,
        const struct nfs4_deviceid *d_id, struct osd_dev *od,
        gfp_t gfp_flags)
{
        struct nfs4_deviceid_node *d;
        struct objio_dev_ent *de = kzalloc(sizeof(*de), gfp_flags);
        struct objio_dev_ent *n;

        if (!de) {
                dprintk("%s: -ENOMEM od=%p\n", __func__, od);
                return NULL;
        }

        dprintk("%s: Adding od=%p\n", __func__, od);
        nfs4_init_deviceid_node(&de->id_node,
                                nfss->pnfs_curr_ld,
                                nfss->nfs_client,
                                d_id);
        de->od = od;

        d = nfs4_insert_deviceid_node(&de->id_node);
        n = container_of(d, struct objio_dev_ent, id_node);
        if (n != de) {
                dprintk("%s: Race with other n->od=%p\n", __func__, n->od);
                objio_free_deviceid_node(&de->id_node);
                de = n;
        }

        return de;
}

struct caps_buffers {
        u8 caps_key[OSD_CRYPTO_KEYID_SIZE];
        u8 creds[OSD_CAP_LEN];
};

struct objio_segment {
        struct pnfs_layout_segment lseg;

        struct pnfs_osd_object_cred *comps;

        unsigned mirrors_p1;
        unsigned stripe_unit;
        unsigned group_width;   /* Data stripe_units without integrity comps */
        u64 group_depth;
        unsigned group_count;

        unsigned max_io_size;

        unsigned comps_index;
        unsigned num_comps;
        /* variable length */
        struct objio_dev_ent *ods[];
};

static inline struct objio_segment *
OBJIO_LSEG(struct pnfs_layout_segment *lseg)
{
        return container_of(lseg, struct objio_segment, lseg);
}

struct objio_state;
typedef ssize_t (*objio_done_fn)(struct objio_state *ios);

struct objio_state {
        /* Generic layer */
        struct objlayout_io_state ol_state;

        struct objio_segment *layout;

        struct kref kref;
        objio_done_fn done;
        void *private;

        unsigned long length;
        unsigned numdevs; /* Actually used devs in this IO */
        /* A per-device variable array of size numdevs */
        struct _objio_per_comp {
                struct bio *bio;
                struct osd_request *or;
                unsigned long length;
                u64 offset;
                unsigned dev;
        } per_dev[];
};

/* Send and wait for a get_device_info of devices in the layout,
   then look them up with the osd_initiator library */
static struct objio_dev_ent *_device_lookup(struct pnfs_layout_hdr *pnfslay,
                                struct objio_segment *objio_seg, unsigned comp,
                                gfp_t gfp_flags)
{
        struct pnfs_osd_deviceaddr *deviceaddr;
        struct nfs4_deviceid *d_id;
        struct objio_dev_ent *ode;
        struct osd_dev *od;
        struct osd_dev_info odi;
        int err;

        d_id = &objio_seg->comps[comp].oc_object_id.oid_device_id;

        ode = _dev_list_find(NFS_SERVER(pnfslay->plh_inode), d_id);
        if (ode)
                return ode;

        err = objlayout_get_deviceinfo(pnfslay, d_id, &deviceaddr, gfp_flags);
        if (unlikely(err)) {
                dprintk("%s: objlayout_get_deviceinfo dev(%llx:%llx) =>%d\n",
                        __func__, _DEVID_LO(d_id), _DEVID_HI(d_id), err);
                return ERR_PTR(err);
        }

        odi.systemid_len = deviceaddr->oda_systemid.len;
        if (odi.systemid_len > sizeof(odi.systemid)) {
                err = -EINVAL;
                goto out;
        } else if (odi.systemid_len)
                memcpy(odi.systemid, deviceaddr->oda_systemid.data,
                       odi.systemid_len);
        odi.osdname_len  = deviceaddr->oda_osdname.len;
        odi.osdname      = (u8 *)deviceaddr->oda_osdname.data;

        if (!odi.osdname_len && !odi.systemid_len) {
                dprintk("%s: !odi.osdname_len && !odi.systemid_len\n",
                        __func__);
                err = -ENODEV;
                goto out;
        }

        od = osduld_info_lookup(&odi);
        if (unlikely(IS_ERR(od))) {
                err = PTR_ERR(od);
                dprintk("%s: osduld_info_lookup => %d\n", __func__, err);
                goto out;
        }

        ode = _dev_list_add(NFS_SERVER(pnfslay->plh_inode), d_id, od,
                            gfp_flags);

out:
        dprintk("%s: return=%d\n", __func__, err);
        objlayout_put_deviceinfo(deviceaddr);
        return err ? ERR_PTR(err) : ode;
}

static int objio_devices_lookup(struct pnfs_layout_hdr *pnfslay,
        struct objio_segment *objio_seg,
        gfp_t gfp_flags)
{
        unsigned i;
        int err;

        /* lookup all devices */
        for (i = 0; i < objio_seg->num_comps; i++) {
                struct objio_dev_ent *ode;

                ode = _device_lookup(pnfslay, objio_seg, i, gfp_flags);
                if (unlikely(IS_ERR(ode))) {
                        err = PTR_ERR(ode);
                        goto out;
                }
                objio_seg->ods[i] = ode;
        }
        err = 0;

out:
        dprintk("%s: return=%d\n", __func__, err);
        return err;
}

static int _verify_data_map(struct pnfs_osd_layout *layout)
{
        struct pnfs_osd_data_map *data_map = &layout->olo_map;
        u64 stripe_length;
        u32 group_width;

/* FIXME: Only raid0 for now. if not go through MDS */
        if (data_map->odm_raid_algorithm != PNFS_OSD_RAID_0) {
                printk(KERN_ERR "Only RAID_0 for now\n");
                return -ENOTSUPP;
        }
        if (0 != (data_map->odm_num_comps % (data_map->odm_mirror_cnt + 1))) {
                printk(KERN_ERR "Data Map wrong, num_comps=%u mirrors=%u\n",
                          data_map->odm_num_comps, data_map->odm_mirror_cnt);
                return -EINVAL;
        }

        if (data_map->odm_group_width)
                group_width = data_map->odm_group_width;
        else
                group_width = data_map->odm_num_comps /
                                                (data_map->odm_mirror_cnt + 1);

        stripe_length = (u64)data_map->odm_stripe_unit * group_width;
        if (stripe_length >= (1ULL << 32)) {
                printk(KERN_ERR "Total Stripe length(0x%llx)"
                          " >= 32bit is not supported\n", _LLU(stripe_length));
                return -ENOTSUPP;
        }

        if (0 != (data_map->odm_stripe_unit & ~PAGE_MASK)) {
                printk(KERN_ERR "Stripe Unit(0x%llx)"
                          " must be Multples of PAGE_SIZE(0x%lx)\n",
                          _LLU(data_map->odm_stripe_unit), PAGE_SIZE);
                return -ENOTSUPP;
        }

        return 0;
}

static void copy_single_comp(struct pnfs_osd_object_cred *cur_comp,
                             struct pnfs_osd_object_cred *src_comp,
                             struct caps_buffers *caps_p)
{
        WARN_ON(src_comp->oc_cap_key.cred_len > sizeof(caps_p->caps_key));
        WARN_ON(src_comp->oc_cap.cred_len > sizeof(caps_p->creds));

        *cur_comp = *src_comp;

        memcpy(caps_p->caps_key, src_comp->oc_cap_key.cred,
               sizeof(caps_p->caps_key));
        cur_comp->oc_cap_key.cred = caps_p->caps_key;

        memcpy(caps_p->creds, src_comp->oc_cap.cred,
               sizeof(caps_p->creds));
        cur_comp->oc_cap.cred = caps_p->creds;
}

int objio_alloc_lseg(struct pnfs_layout_segment **outp,
        struct pnfs_layout_hdr *pnfslay,
        struct pnfs_layout_range *range,
        struct xdr_stream *xdr,
        gfp_t gfp_flags)
{
        struct objio_segment *objio_seg;
        struct pnfs_osd_xdr_decode_layout_iter iter;
        struct pnfs_osd_layout layout;
        struct pnfs_osd_object_cred *cur_comp, src_comp;
        struct caps_buffers *caps_p;
        int err;

        err = pnfs_osd_xdr_decode_layout_map(&layout, &iter, xdr);
        if (unlikely(err))
                return err;

        err = _verify_data_map(&layout);
        if (unlikely(err))
                return err;

        objio_seg = kzalloc(sizeof(*objio_seg) +
                            sizeof(objio_seg->ods[0]) * layout.olo_num_comps +
                            sizeof(*objio_seg->comps) * layout.olo_num_comps +
                            sizeof(struct caps_buffers) * layout.olo_num_comps,
                            gfp_flags);
        if (!objio_seg)
                return -ENOMEM;

        objio_seg->comps = (void *)(objio_seg->ods + layout.olo_num_comps);
        cur_comp = objio_seg->comps;
        caps_p = (void *)(cur_comp + layout.olo_num_comps);
        while (pnfs_osd_xdr_decode_layout_comp(&src_comp, &iter, xdr, &err))
                copy_single_comp(cur_comp++, &src_comp, caps_p++);
        if (unlikely(err))
                goto err;

        objio_seg->num_comps = layout.olo_num_comps;
        objio_seg->comps_index = layout.olo_comps_index;
        err = objio_devices_lookup(pnfslay, objio_seg, gfp_flags);
        if (err)
                goto err;

        objio_seg->mirrors_p1 = layout.olo_map.odm_mirror_cnt + 1;
        objio_seg->stripe_unit = layout.olo_map.odm_stripe_unit;
        if (layout.olo_map.odm_group_width) {
                objio_seg->group_width = layout.olo_map.odm_group_width;
                objio_seg->group_depth = layout.olo_map.odm_group_depth;
                objio_seg->group_count = layout.olo_map.odm_num_comps /
                                                objio_seg->mirrors_p1 /
                                                objio_seg->group_width;
        } else {
                objio_seg->group_width = layout.olo_map.odm_num_comps /
                                                objio_seg->mirrors_p1;
                objio_seg->group_depth = -1;
                objio_seg->group_count = 1;
        }

        /* Cache this calculation it will hit for every page */
        objio_seg->max_io_size = (BIO_MAX_PAGES_KMALLOC * PAGE_SIZE -
                                  objio_seg->stripe_unit) *
                                 objio_seg->group_width;

        *outp = &objio_seg->lseg;
        return 0;

err:
        kfree(objio_seg);
        dprintk("%s: Error: return %d\n", __func__, err);
        *outp = NULL;
        return err;
}

void objio_free_lseg(struct pnfs_layout_segment *lseg)
{
        int i;
        struct objio_segment *objio_seg = OBJIO_LSEG(lseg);

        for (i = 0; i < objio_seg->num_comps; i++) {
                if (!objio_seg->ods[i])
                        break;
                nfs4_put_deviceid_node(&objio_seg->ods[i]->id_node);
        }
        kfree(objio_seg);
}

int objio_alloc_io_state(struct pnfs_layout_segment *lseg,
                         struct objlayout_io_state **outp,
                         gfp_t gfp_flags)
{
        struct objio_segment *objio_seg = OBJIO_LSEG(lseg);
        struct objio_state *ios;
        const unsigned first_size = sizeof(*ios) +
                                objio_seg->num_comps * sizeof(ios->per_dev[0]);
        const unsigned sec_size = objio_seg->num_comps *
                                                sizeof(ios->ol_state.ioerrs[0]);

        ios = kzalloc(first_size + sec_size, gfp_flags);
        if (unlikely(!ios))
                return -ENOMEM;

        ios->layout = objio_seg;
        ios->ol_state.ioerrs = ((void *)ios) + first_size;
        ios->ol_state.num_comps = objio_seg->num_comps;

        *outp = &ios->ol_state;
        return 0;
}

void objio_free_io_state(struct objlayout_io_state *ol_state)
{
        struct objio_state *ios = container_of(ol_state, struct objio_state,
                                               ol_state);

        kfree(ios);
}

enum pnfs_osd_errno osd_pri_2_pnfs_err(enum osd_err_priority oep)
{
        switch (oep) {
        case OSD_ERR_PRI_NO_ERROR:
                return (enum pnfs_osd_errno)0;

        case OSD_ERR_PRI_CLEAR_PAGES:
                BUG_ON(1);
                return 0;

        case OSD_ERR_PRI_RESOURCE:
                return PNFS_OSD_ERR_RESOURCE;
        case OSD_ERR_PRI_BAD_CRED:
                return PNFS_OSD_ERR_BAD_CRED;
        case OSD_ERR_PRI_NO_ACCESS:
                return PNFS_OSD_ERR_NO_ACCESS;
        case OSD_ERR_PRI_UNREACHABLE:
                return PNFS_OSD_ERR_UNREACHABLE;
        case OSD_ERR_PRI_NOT_FOUND:
                return PNFS_OSD_ERR_NOT_FOUND;
        case OSD_ERR_PRI_NO_SPACE:
                return PNFS_OSD_ERR_NO_SPACE;
        default:
                WARN_ON(1);
                /* fallthrough */
        case OSD_ERR_PRI_EIO:
                return PNFS_OSD_ERR_EIO;
        }
}

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);
        }
}

static int _io_check(struct objio_state *ios, bool is_write)
{
        enum osd_err_priority oep = OSD_ERR_PRI_NO_ERROR;
        int lin_ret = 0;
        int i;

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

                if (!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 */
                        BUG_ON(is_write);
                        _clear_bio(ios->per_dev[i].bio);
                        dprintk("%s: start read offset passed end of file "
                                "offset=0x%llx, length=0x%lx\n", __func__,
                                _LLU(ios->per_dev[i].offset),
                                ios->per_dev[i].length);

                        continue; /* we recovered */
                }
                dev = ios->per_dev[i].dev;
                objlayout_io_set_result(&ios->ol_state, dev,
                                        &ios->layout->comps[dev].oc_object_id,
                                        osd_pri_2_pnfs_err(osi.osd_err_pri),
                                        ios->per_dev[i].offset,
                                        ios->per_dev[i].length,
                                        is_write);

                if (osi.osd_err_pri >= oep) {
                        oep = osi.osd_err_pri;
                        lin_ret = ret;
                }
        }

        return lin_ret;
}

/*
 * Common IO state helpers.
 */
static void _io_free(struct objio_state *ios)
{
        unsigned i;

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

                if (per_dev->or) {
                        osd_end_request(per_dev->or);
                        per_dev->or = NULL;
                }

                if (per_dev->bio) {
                        bio_put(per_dev->bio);
                        per_dev->bio = NULL;
                }
        }
}

struct osd_dev *_io_od(struct objio_state *ios, unsigned dev)
{
        unsigned min_dev = ios->layout->comps_index;
        unsigned max_dev = min_dev + ios->layout->num_comps;

        BUG_ON(dev < min_dev || max_dev <= dev);
        return ios->layout->ods[dev - min_dev]->od;
}

struct _striping_info {
        u64 obj_offset;
        u64 group_length;
        unsigned dev;
        unsigned unit_off;
};

static void _calc_stripe_info(struct objio_state *ios, u64 file_offset,
                              struct _striping_info *si)
{
        u32     stripe_unit = ios->layout->stripe_unit;
        u32     group_width = ios->layout->group_width;
        u64     group_depth = ios->layout->group_depth;
        u32     U = stripe_unit * group_width;

        u64     T = U * group_depth;
        u64     S = T * ios->layout->group_count;
        u64     M = div64_u64(file_offset, S);

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

        u32     N = div_u64(H, U);

        div_u64_rem(file_offset, stripe_unit, &si->unit_off);
        si->obj_offset = si->unit_off + (N * stripe_unit) +
                                  (M * group_depth * stripe_unit);

        /* "H - (N * U)" is just "H % U" so it's bound to u32 */
        si->dev = (u32)(H - (N * U)) / stripe_unit + G * group_width;
        si->dev *= ios->layout->mirrors_p1;

        si->group_length = T - H;
}

static int _add_stripe_unit(struct objio_state *ios,  unsigned *cur_pg,
                unsigned pgbase, struct _objio_per_comp *per_dev, int cur_len,
                gfp_t gfp_flags)
{
        unsigned pg = *cur_pg;
        struct request_queue *q =
                        osd_request_queue(_io_od(ios, per_dev->dev));

        per_dev->length += cur_len;

        if (per_dev->bio == NULL) {
                unsigned stripes = ios->layout->num_comps /
                                                     ios->layout->mirrors_p1;
                unsigned pages_in_stripe = stripes *
                                      (ios->layout->stripe_unit / PAGE_SIZE);
                unsigned bio_size = (ios->ol_state.nr_pages + pages_in_stripe) /
                                    stripes;

                if (BIO_MAX_PAGES_KMALLOC < bio_size)
                        bio_size = BIO_MAX_PAGES_KMALLOC;

                per_dev->bio = bio_kmalloc(gfp_flags, bio_size);
                if (unlikely(!per_dev->bio)) {
                        dprintk("Faild to allocate BIO size=%u\n", bio_size);
                        return -ENOMEM;
                }
        }

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

                BUG_ON(ios->ol_state.nr_pages <= pg);
                cur_len -= pglen;

                added_len = bio_add_pc_page(q, per_dev->bio,
                                        ios->ol_state.pages[pg], pglen, pgbase);
                if (unlikely(pglen != added_len))
                        return -ENOMEM;
                pgbase = 0;
                ++pg;
        }
        BUG_ON(cur_len);

        *cur_pg = pg;
        return 0;
}

static int _prepare_one_group(struct objio_state *ios, u64 length,
                              struct _striping_info *si, unsigned *last_pg,
                              gfp_t gfp_flags)
{
        unsigned stripe_unit = ios->layout->stripe_unit;
        unsigned mirrors_p1 = ios->layout->mirrors_p1;
        unsigned devs_in_group = ios->layout->group_width * mirrors_p1;
        unsigned dev = si->dev;
        unsigned first_dev = dev - (dev % devs_in_group);
        unsigned max_comp = ios->numdevs ? ios->numdevs - mirrors_p1 : 0;
        unsigned cur_pg = *last_pg;
        int ret = 0;

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

                if (!per_dev->length) {
                        per_dev->dev = dev;
                        if (dev < si->dev) {
                                per_dev->offset = si->obj_offset + stripe_unit -
                                                                   si->unit_off;
                                cur_len = stripe_unit;
                        } else if (dev == si->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->ol_state.pgbase));
                        } else { /* dev > si->dev */
                                per_dev->offset = si->obj_offset - si->unit_off;
                                cur_len = stripe_unit;
                        }

                        if (max_comp < dev)
                                max_comp = dev;
                } else {
                        cur_len = stripe_unit;
                }
                if (cur_len >= length)
                        cur_len = length;

                ret = _add_stripe_unit(ios, &cur_pg, page_off , per_dev,
                                       cur_len, gfp_flags);
                if (unlikely(ret))
                        goto out;

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

                length -= cur_len;
                ios->length += cur_len;
        }
out:
        ios->numdevs = max_comp + mirrors_p1;
        *last_pg = cur_pg;
        return ret;
}

static int _io_rw_pagelist(struct objio_state *ios, gfp_t gfp_flags)
{
        u64 length = ios->ol_state.count;
        u64 offset = ios->ol_state.offset;
        struct _striping_info si;
        unsigned last_pg = 0;
        int ret = 0;

        while (length) {
                _calc_stripe_info(ios, offset, &si);

                if (length < si.group_length)
                        si.group_length = length;

                ret = _prepare_one_group(ios, si.group_length, &si, &last_pg, gfp_flags);
                if (unlikely(ret))
                        goto out;

                offset += si.group_length;
                length -= si.group_length;
        }

out:
        if (!ios->length)
                return ret;

        return 0;
}

static ssize_t _sync_done(struct objio_state *ios)
{
        struct completion *waiting = ios->private;

        complete(waiting);
        return 0;
}

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

        ios->done(ios);
}

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

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

static ssize_t _io_exec(struct objio_state *ios)
{
        DECLARE_COMPLETION_ONSTACK(wait);
        ssize_t status = 0; /* sync status */
        unsigned i;
        objio_done_fn saved_done_fn = ios->done;
        bool sync = ios->ol_state.sync;

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

        kref_init(&ios->kref);

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

                if (!or)
                        continue;

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

        kref_put(&ios->kref, _last_io);

        if (sync) {
                wait_for_completion(&wait);
                status = saved_done_fn(ios);
        }

        return status;
}

/*
 * read
 */
static ssize_t _read_done(struct objio_state *ios)
{
        ssize_t status;
        int ret = _io_check(ios, false);

        _io_free(ios);

        if (likely(!ret))
                status = ios->length;
        else
                status = ret;

        objlayout_read_done(&ios->ol_state, status, ios->ol_state.sync);
        return status;
}

static int _read_mirrors(struct objio_state *ios, unsigned cur_comp)
{
        struct osd_request *or = NULL;
        struct _objio_per_comp *per_dev = &ios->per_dev[cur_comp];
        unsigned dev = per_dev->dev;
        struct pnfs_osd_object_cred *cred =
                        &ios->layout->comps[dev];
        struct osd_obj_id obj = {
                .partition = cred->oc_object_id.oid_partition_id,
                .id = cred->oc_object_id.oid_object_id,
        };
        int ret;

        or = osd_start_request(_io_od(ios, dev), GFP_KERNEL);
        if (unlikely(!or)) {
                ret = -ENOMEM;
                goto err;
        }
        per_dev->or = or;

        osd_req_read(or, &obj, per_dev->offset, per_dev->bio, per_dev->length);

        ret = osd_finalize_request(or, 0, cred->oc_cap.cred, NULL);
        if (ret) {
                dprintk("%s: Faild to osd_finalize_request() => %d\n",
                        __func__, ret);
                goto err;
        }

        dprintk("%s:[%d] dev=%d obj=0x%llx start=0x%llx length=0x%lx\n",
                __func__, cur_comp, dev, obj.id, _LLU(per_dev->offset),
                per_dev->length);

err:
        return ret;
}

static ssize_t _read_exec(struct objio_state *ios)
{
        unsigned i;
        int ret;

        for (i = 0; i < ios->numdevs; i += ios->layout->mirrors_p1) {
                if (!ios->per_dev[i].length)
                        continue;
                ret = _read_mirrors(ios, i);
                if (unlikely(ret))
                        goto err;
        }

        ios->done = _read_done;
        return _io_exec(ios); /* In sync mode exec returns the io status */

err:
        _io_free(ios);
        return ret;
}

ssize_t objio_read_pagelist(struct objlayout_io_state *ol_state)
{
        struct objio_state *ios = container_of(ol_state, struct objio_state,
                                               ol_state);
        int ret;

        ret = _io_rw_pagelist(ios, GFP_KERNEL);
        if (unlikely(ret))
                return ret;

        return _read_exec(ios);
}

/*
 * write
 */
static ssize_t _write_done(struct objio_state *ios)
{
        ssize_t status;
        int ret = _io_check(ios, true);

        _io_free(ios);

        if (likely(!ret)) {
                /* FIXME: should be based on the OSD's persistence model
                 * See OSD2r05 Section 4.13 Data persistence model */
                ios->ol_state.committed = NFS_FILE_SYNC;
                status = ios->length;
        } else {
                status = ret;
        }

        objlayout_write_done(&ios->ol_state, status, ios->ol_state.sync);
        return status;
}

static int _write_mirrors(struct objio_state *ios, unsigned cur_comp)
{
        struct _objio_per_comp *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;

        for (; cur_comp < last_comp; ++cur_comp, ++dev) {
                struct osd_request *or = NULL;
                struct pnfs_osd_object_cred *cred =
                                        &ios->layout->comps[dev];
                struct osd_obj_id obj = {
                        .partition = cred->oc_object_id.oid_partition_id,
                        .id = cred->oc_object_id.oid_object_id,
                };
                struct _objio_per_comp *per_dev = &ios->per_dev[cur_comp];
                struct bio *bio;

                or = osd_start_request(_io_od(ios, dev), GFP_NOFS);
                if (unlikely(!or)) {
                        ret = -ENOMEM;
                        goto err;
                }
                per_dev->or = or;

                if (per_dev != master_dev) {
                        bio = bio_kmalloc(GFP_NOFS,
                                          master_dev->bio->bi_max_vecs);
                        if (unlikely(!bio)) {
                                dprintk("Faild to allocate BIO size=%u\n",
                                        master_dev->bio->bi_max_vecs);
                                ret = -ENOMEM;
                                goto err;
                        }

                        __bio_clone(bio, master_dev->bio);
                        bio->bi_bdev = NULL;
                        bio->bi_next = NULL;
                        per_dev->bio = bio;
                        per_dev->dev = dev;
                        per_dev->length = master_dev->length;
                        per_dev->offset =  master_dev->offset;
                } else {
                        bio = master_dev->bio;
                        bio->bi_rw |= REQ_WRITE;
                }

                osd_req_write(or, &obj, per_dev->offset, bio, per_dev->length);

                ret = osd_finalize_request(or, 0, cred->oc_cap.cred, NULL);
                if (ret) {
                        dprintk("%s: Faild to osd_finalize_request() => %d\n",
                                __func__, ret);
                        goto err;
                }

                dprintk("%s:[%d] dev=%d obj=0x%llx start=0x%llx length=0x%lx\n",
                        __func__, cur_comp, dev, obj.id, _LLU(per_dev->offset),
                        per_dev->length);
        }

err:
        return ret;
}

static ssize_t _write_exec(struct objio_state *ios)
{
        unsigned i;
        int ret;

        for (i = 0; i < ios->numdevs; i += ios->layout->mirrors_p1) {
                if (!ios->per_dev[i].length)
                        continue;
                ret = _write_mirrors(ios, i);
                if (unlikely(ret))
                        goto err;
        }

        ios->done = _write_done;
        return _io_exec(ios); /* In sync mode exec returns the io->status */

err:
        _io_free(ios);
        return ret;
}

ssize_t objio_write_pagelist(struct objlayout_io_state *ol_state, bool stable)
{
        struct objio_state *ios = container_of(ol_state, struct objio_state,
                                               ol_state);
        int ret;

        /* TODO: ios->stable = stable; */
        ret = _io_rw_pagelist(ios, GFP_NOFS);
        if (unlikely(ret))
                return ret;

        return _write_exec(ios);
}

static bool objio_pg_test(struct nfs_pageio_descriptor *pgio,
                          struct nfs_page *prev, struct nfs_page *req)
{
        if (!pnfs_generic_pg_test(pgio, prev, req))
                return false;

        return pgio->pg_count + req->wb_bytes <=
                        OBJIO_LSEG(pgio->pg_lseg)->max_io_size;
}

static const struct nfs_pageio_ops objio_pg_read_ops = {
        .pg_init = pnfs_generic_pg_init_read,
        .pg_test = objio_pg_test,
        .pg_doio = pnfs_generic_pg_readpages,
};

static const struct nfs_pageio_ops objio_pg_write_ops = {
        .pg_init = pnfs_generic_pg_init_write,
        .pg_test = objio_pg_test,
        .pg_doio = pnfs_generic_pg_writepages,
};

static struct pnfs_layoutdriver_type objlayout_type = {
        .id = LAYOUT_OSD2_OBJECTS,
        .name = "LAYOUT_OSD2_OBJECTS",
        .flags                   = PNFS_LAYOUTRET_ON_SETATTR,

        .alloc_layout_hdr        = objlayout_alloc_layout_hdr,
        .free_layout_hdr         = objlayout_free_layout_hdr,

        .alloc_lseg              = objlayout_alloc_lseg,
        .free_lseg               = objlayout_free_lseg,

        .read_pagelist           = objlayout_read_pagelist,
        .write_pagelist          = objlayout_write_pagelist,
        .pg_read_ops             = &objio_pg_read_ops,
        .pg_write_ops            = &objio_pg_write_ops,

        .free_deviceid_node      = objio_free_deviceid_node,

        .encode_layoutcommit     = objlayout_encode_layoutcommit,
        .encode_layoutreturn     = objlayout_encode_layoutreturn,
};

MODULE_DESCRIPTION("pNFS Layout Driver for OSD2 objects");
MODULE_AUTHOR("Benny Halevy <bhalevy@panasas.com>");
MODULE_LICENSE("GPL");

static int __init
objlayout_init(void)
{
        int ret = pnfs_register_layoutdriver(&objlayout_type);

        if (ret)
                printk(KERN_INFO
                        "%s: Registering OSD pNFS Layout Driver failed: error=%d\n",
                        __func__, ret);
        else
                printk(KERN_INFO "%s: Registered OSD pNFS Layout Driver\n",
                        __func__);
        return ret;
}

static void __exit
objlayout_exit(void)
{
        pnfs_unregister_layoutdriver(&objlayout_type);
        printk(KERN_INFO "%s: Unregistered OSD pNFS Layout Driver\n",
               __func__);
}

MODULE_ALIAS("nfs-layouttype4-2");

module_init(objlayout_init);
module_exit(objlayout_exit);