source: mainline/uspace/srv/bd/hr/util.c@ 8b51009

/*
 * Copyright (c) 2025 Miroslav Cimerman
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - 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.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
 */

/** @addtogroup hr
 * @{
 */
/**
 * @file
 */

#include <adt/list.h>
#include <block.h>
#include <errno.h>
#include <fibril_synch.h>
#include <hr.h>
#include <io/log.h>
#include <loc.h>
#include <mem.h>
#include <stdatomic.h>
#include <stdlib.h>
#include <stdio.h>
#include <str_error.h>
#include <vbd.h>

#include "io.h"
#include "superblock.h"
#include "util.h"
#include "var.h"

#define HR_RL_LIST_LOCK(vol) (fibril_mutex_lock(&vol->range_lock_list_lock))
#define HR_RL_LIST_UNLOCK(vol) \
    (fibril_mutex_unlock(&vol->range_lock_list_lock))

static bool hr_range_lock_overlap(hr_range_lock_t *, hr_range_lock_t *);

extern loc_srv_t *hr_srv;
extern list_t hr_volumes;
extern fibril_rwlock_t hr_volumes_lock;

errno_t hr_create_vol_struct(hr_volume_t **rvol, hr_level_t level)
{
        errno_t rc;

        hr_volume_t *vol = calloc(1, sizeof(hr_volume_t));
        if (vol == NULL)
                return ENOMEM;

        vol->level = level;

        switch (level) {
        case HR_LVL_1:
                vol->hr_ops.create = hr_raid1_create;
                vol->hr_ops.init = hr_raid1_init;
                vol->hr_ops.status_event = hr_raid1_status_event;
                vol->hr_ops.add_hotspare = hr_raid1_add_hotspare;
                break;
        case HR_LVL_0:
                vol->hr_ops.create = hr_raid0_create;
                vol->hr_ops.init = hr_raid0_init;
                vol->hr_ops.status_event = hr_raid0_status_event;
                break;
        case HR_LVL_4:
                vol->hr_ops.create = hr_raid5_create;
                vol->hr_ops.init = hr_raid5_init;
                vol->hr_ops.status_event = hr_raid5_status_event;
                vol->hr_ops.add_hotspare = hr_raid5_add_hotspare;
                break;
        case HR_LVL_5:
                vol->hr_ops.create = hr_raid5_create;
                vol->hr_ops.init = hr_raid5_init;
                vol->hr_ops.status_event = hr_raid5_status_event;
                vol->hr_ops.add_hotspare = hr_raid5_add_hotspare;
                break;
        default:
                HR_DEBUG("unkown level: %d, aborting\n", vol->level);
                rc = EINVAL;
                goto error;
        }

        vol->fge = hr_fpool_create(16, 32, sizeof(hr_io_t));
        if (vol->fge == NULL) {
                rc = ENOMEM;
                goto error;
        }

        vol->status = HR_VOL_NONE;

        for (size_t i = 0; i < HR_MAX_EXTENTS; ++i)
                vol->extents[i].status = HR_EXT_MISSING;

        for (size_t i = 0; i < HR_MAX_HOTSPARES; ++i)
                vol->extents[i].status = HR_EXT_MISSING;

        fibril_mutex_initialize(&vol->lock); /* XXX: will remove this */

        fibril_rwlock_initialize(&vol->extents_lock);
        fibril_rwlock_initialize(&vol->states_lock);

        fibril_mutex_initialize(&vol->hotspare_lock);

        list_initialize(&vol->range_lock_list);
        fibril_mutex_initialize(&vol->range_lock_list_lock);

        atomic_init(&vol->rebuild_blk, 0);
        atomic_init(&vol->state_dirty, false);
        atomic_init(&vol->open_cnt, 0);

        *rvol = vol;

        return EOK;
error:
        free(vol);
        return rc;
}

void hr_destroy_vol_struct(hr_volume_t *vol)
{
        if (vol == NULL)
                return;

        hr_fpool_destroy(vol->fge);
        hr_fini_devs(vol);
        free(vol->in_mem_md);
        free(vol);
}

hr_volume_t *hr_get_volume(service_id_t svc_id)
{
        HR_DEBUG("hr_get_volume(): (%" PRIun ")\n", svc_id);

        hr_volume_t *rvol = NULL;

        fibril_rwlock_read_lock(&hr_volumes_lock);
        list_foreach(hr_volumes, lvolumes, hr_volume_t, iter) {
                if (iter->svc_id == svc_id) {
                        rvol = iter;
                        break;
                }
        }

        fibril_rwlock_read_unlock(&hr_volumes_lock);
        return rvol;
}

errno_t hr_remove_volume(service_id_t svc_id)
{
        HR_DEBUG("hr_remove_volume(): (%" PRIun ")\n", svc_id);

        errno_t rc;

        fibril_rwlock_write_lock(&hr_volumes_lock);
        list_foreach(hr_volumes, lvolumes, hr_volume_t, vol) {
                if (vol->svc_id == svc_id) {
                        int open_cnt = atomic_load_explicit(&vol->open_cnt,
                            memory_order_relaxed);
                        /*
                         * The "atomicity" of this if condition is provided
                         * by the write lock - no new bd connection can
                         * come, because we need to get the bd_srvs_t from
                         * volume, which we get from the list.
                         * (see hr_client_conn() in hr.c)
                         */
                        if (open_cnt > 0) {
                                fibril_rwlock_write_unlock(&hr_volumes_lock);
                                return EBUSY;
                        }
                        list_remove(&vol->lvolumes);
                        fibril_rwlock_write_unlock(&hr_volumes_lock);

                        hr_destroy_vol_struct(vol);

                        rc = loc_service_unregister(hr_srv, svc_id);
                        return rc;
                }
        }

        fibril_rwlock_write_unlock(&hr_volumes_lock);
        return ENOENT;
}

errno_t hr_init_devs(hr_volume_t *vol)
{
        HR_DEBUG("%s()", __func__);

        errno_t rc;
        size_t i;
        hr_extent_t *extent;

        for (i = 0; i < vol->extent_no; i++) {
                extent = &vol->extents[i];
                if (extent->svc_id == 0) {
                        extent->status = HR_EXT_MISSING;
                        continue;
                }

                HR_DEBUG("hr_init_devs(): block_init() on (%lu)\n",
                    extent->svc_id);
                rc = block_init(extent->svc_id);
                extent->status = HR_EXT_ONLINE;

                if (rc != EOK) {
                        HR_ERROR("hr_init_devs(): initing (%lu) failed, "
                            "aborting\n", extent->svc_id);
                        break;
                }
        }

        for (i = 0; i < HR_MAX_HOTSPARES; i++)
                vol->hotspares[i].status = HR_EXT_MISSING;

        return rc;
}

void hr_fini_devs(hr_volume_t *vol)
{
        HR_DEBUG("%s()", __func__);

        size_t i;

        for (i = 0; i < vol->extent_no; i++) {
                if (vol->extents[i].svc_id != 0) {
                        HR_DEBUG("hr_fini_devs(): block_fini() on (%lu)\n",
                            vol->extents[i].svc_id);
                        block_fini(vol->extents[i].svc_id);
                }
        }
}

errno_t hr_register_volume(hr_volume_t *vol)
{
        HR_DEBUG("%s()", __func__);

        errno_t rc;
        service_id_t new_id;
        category_id_t cat_id;
        char *fullname = NULL;
        char *devname = vol->devname;

        if (asprintf(&fullname, "devices/%s", devname) < 0)
                return ENOMEM;

        rc = loc_service_register(hr_srv, fullname, &new_id);
        if (rc != EOK) {
                HR_ERROR("unable to register device \"%s\": %s\n",
                    fullname, str_error(rc));
                goto error;
        }

        rc = loc_category_get_id("raid", &cat_id, IPC_FLAG_BLOCKING);
        if (rc != EOK) {
                HR_ERROR("failed resolving category \"raid\": %s\n",
                    str_error(rc));
                goto error;
        }

        rc = loc_service_add_to_cat(hr_srv, new_id, cat_id);
        if (rc != EOK) {
                HR_ERROR("failed adding \"%s\" to category \"raid\": %s\n",
                    fullname, str_error(rc));
                goto error;
        }

        vol->svc_id = new_id;
error:
        free(fullname);
        return rc;
}

errno_t hr_check_devs(hr_volume_t *vol, uint64_t *rblkno, size_t *rbsize)
{
        HR_DEBUG("%s()", __func__);

        errno_t rc;
        size_t i, bsize;
        uint64_t nblocks;
        size_t last_bsize = 0;
        uint64_t last_nblocks = 0;
        uint64_t total_blocks = 0;
        hr_extent_t *extent;

        for (i = 0; i < vol->extent_no; i++) {
                extent = &vol->extents[i];
                if (extent->status == HR_EXT_MISSING)
                        continue;
                rc = block_get_nblocks(extent->svc_id, &nblocks);
                if (rc != EOK)
                        goto error;
                if (last_nblocks != 0 && nblocks != last_nblocks) {
                        HR_ERROR("number of blocks differs\n");
                        rc = EINVAL;
                        goto error;
                }

                total_blocks += nblocks;
                last_nblocks = nblocks;
        }

        for (i = 0; i < vol->extent_no; i++) {
                extent = &vol->extents[i];
                if (extent->status == HR_EXT_MISSING)
                        continue;
                rc = block_get_bsize(extent->svc_id, &bsize);
                if (rc != EOK)
                        goto error;
                if (last_bsize != 0 && bsize != last_bsize) {
                        HR_ERROR("block sizes differ\n");
                        rc = EINVAL;
                        goto error;
                }

                last_bsize = bsize;
        }

        if ((bsize % 512) != 0) {
                HR_ERROR("block size not multiple of 512\n");
                return EINVAL;
        }

        if (rblkno != NULL)
                *rblkno = total_blocks;
        if (rbsize != NULL)
                *rbsize = bsize;
error:
        return rc;
}

errno_t hr_check_ba_range(hr_volume_t *vol, size_t cnt, uint64_t ba)
{
        if (ba + cnt > vol->data_blkno)
                return ERANGE;
        return EOK;
}

void hr_add_ba_offset(hr_volume_t *vol, uint64_t *ba)
{
        *ba = *ba + vol->data_offset;
}

void hr_update_ext_status(hr_volume_t *vol, size_t extent, hr_ext_status_t s)
{
        if (vol->level != HR_LVL_0)
                assert(fibril_rwlock_is_locked(&vol->extents_lock));

        assert(fibril_rwlock_is_write_locked(&vol->states_lock));

        assert(extent < vol->extent_no);

        hr_ext_status_t old = vol->extents[extent].status;
        HR_WARN("\"%s\": changing extent %lu state: %s -> %s\n",
            vol->devname, extent, hr_get_ext_status_msg(old),
            hr_get_ext_status_msg(s));
        vol->extents[extent].status = s;
}

void hr_update_hotspare_status(hr_volume_t *vol, size_t hs, hr_ext_status_t s)
{
        assert(fibril_mutex_is_locked(&vol->hotspare_lock));

        assert(hs < vol->hotspare_no);

        hr_ext_status_t old = vol->hotspares[hs].status;
        HR_WARN("\"%s\": changing hotspare %lu state: %s -> %s\n",
            vol->devname, hs, hr_get_ext_status_msg(old),
            hr_get_ext_status_msg(s));
        vol->hotspares[hs].status = s;
}

void hr_update_vol_status(hr_volume_t *vol, hr_vol_status_t new)
{
        assert(fibril_rwlock_is_write_locked(&vol->states_lock));

        HR_WARN("\"%s\": changing volume state: %s -> %s\n", vol->devname,
            hr_get_vol_status_msg(vol->status), hr_get_vol_status_msg(new));
        vol->status = new;
}

void hr_update_ext_svc_id(hr_volume_t *vol, size_t extent, service_id_t new)
{
        if (vol->level != HR_LVL_0)
                assert(fibril_rwlock_is_write_locked(&vol->extents_lock));

        assert(extent < vol->extent_no);

        service_id_t old = vol->extents[extent].svc_id;
        HR_WARN("\"%s\": changing extent no. %lu svc_id: (%lu) -> (%lu)\n",
            vol->devname, extent, old, new);
        vol->extents[extent].svc_id = new;
}

void hr_update_hotspare_svc_id(hr_volume_t *vol, size_t hs, service_id_t new)
{
        assert(fibril_mutex_is_locked(&vol->hotspare_lock));

        assert(hs < vol->hotspare_no);

        service_id_t old = vol->hotspares[hs].svc_id;
        HR_WARN("\"%s\": changing hotspare no. %lu svc_id: (%lu) -> (%lu)\n",
            vol->devname, hs, old, new);
        vol->hotspares[hs].svc_id = new;
}

/*
 * Do a whole sync (ba = 0, cnt = 0) across all extents,
 * and update extent status. *For now*, the caller has to
 * update volume status after the syncs.
 *
 * TODO: add update_vol_status fcn ptr for each raid
 */
void hr_sync_all_extents(hr_volume_t *vol)
{
        errno_t rc;

        fibril_mutex_lock(&vol->lock);
        for (size_t i = 0; i < vol->extent_no; i++) {
                if (vol->extents[i].status != HR_EXT_ONLINE)
                        continue;
                rc = block_sync_cache(vol->extents[i].svc_id, 0, 0);
                if (rc == ENOMEM || rc == ENOTSUP)
                        continue;
                if (rc != EOK) {
                        if (rc == ENOENT)
                                hr_update_ext_status(vol, i, HR_EXT_MISSING);
                        else if (rc != EOK)
                                hr_update_ext_status(vol, i, HR_EXT_FAILED);
                }
        }
        fibril_mutex_unlock(&vol->lock);
}

size_t hr_count_extents(hr_volume_t *vol, hr_ext_status_t status)
{
        if (vol->level != HR_LVL_0)
                assert(fibril_rwlock_is_locked(&vol->extents_lock));
        assert(fibril_rwlock_is_locked(&vol->states_lock));

        size_t count = 0;
        for (size_t i = 0; i < vol->extent_no; i++)
                if (vol->extents[i].status == status)
                        count++;

        return count;
}

hr_range_lock_t *hr_range_lock_acquire(hr_volume_t *vol, uint64_t ba,
    uint64_t cnt)
{
        hr_range_lock_t *rl = malloc(sizeof(hr_range_lock_t));
        if (rl == NULL)
                return NULL;

        rl->vol = vol;
        rl->off = ba;
        rl->len = cnt;

        rl->pending = 1;
        rl->ignore = false;

        link_initialize(&rl->link);
        fibril_mutex_initialize(&rl->lock);

        fibril_mutex_lock(&rl->lock);

again:
        HR_RL_LIST_LOCK(vol);
        list_foreach(vol->range_lock_list, link, hr_range_lock_t, rlp) {
                if (rlp->ignore)
                        continue;
                if (hr_range_lock_overlap(rlp, rl)) {
                        rlp->pending++;

                        HR_RL_LIST_UNLOCK(vol);

                        fibril_mutex_lock(&rlp->lock);

                        HR_RL_LIST_LOCK(vol);

                        rlp->pending--;

                        /*
                         * when ignore is set, after HR_RL_LIST_UNLOCK(),
                         * noone new is going to be able to start sleeping
                         * on the ignored range lock, only already waiting
                         * IOs will come through here
                         */
                        rlp->ignore = true;

                        fibril_mutex_unlock(&rlp->lock);

                        if (rlp->pending == 0) {
                                list_remove(&rlp->link);
                                free(rlp);
                        }

                        HR_RL_LIST_UNLOCK(vol);
                        goto again;
                }
        }

        list_append(&rl->link, &vol->range_lock_list);

        HR_RL_LIST_UNLOCK(vol);
        return rl;
}

void hr_range_lock_release(hr_range_lock_t *rl)
{
        if (rl == NULL)
                return;

        HR_RL_LIST_LOCK(rl->vol);

        rl->pending--;

        fibril_mutex_unlock(&rl->lock);

        if (rl->pending == 0) {
                list_remove(&rl->link);
                free(rl);
        }

        HR_RL_LIST_UNLOCK(rl->vol);
}

static bool hr_range_lock_overlap(hr_range_lock_t *rl1, hr_range_lock_t *rl2)
{
        uint64_t rl1_start = rl1->off;
        uint64_t rl1_end = rl1->off + rl1->len - 1;
        uint64_t rl2_start = rl2->off;
        uint64_t rl2_end = rl2->off + rl2->len - 1;

        /* one ends before the other starts */
        if (rl1_end < rl2_start || rl2_end < rl1_start)
                return false;

        return true;
}

void hr_mark_vol_state_dirty(hr_volume_t *vol)
{
        atomic_store(&vol->state_dirty, true);
}

struct svc_id_linked {
        link_t link;
        service_id_t svc_id;
        hr_metadata_t *md;
        bool inited;
        bool md_present;
};

static errno_t hr_add_svc_linked_to_list(list_t *list, service_id_t svc_id,
    bool inited, hr_metadata_t *md)
{
        errno_t rc = EOK;
        struct svc_id_linked *to_add;

        to_add = malloc(sizeof(struct svc_id_linked));
        if (to_add == NULL) {
                rc = ENOMEM;
                goto error;
        }
        to_add->svc_id = svc_id;
        to_add->inited = inited;

        if (md != NULL) {
                to_add->md = malloc(sizeof(hr_metadata_t));
                if (to_add->md == NULL) {
                        rc = ENOMEM;
                        goto error;
                }
                to_add->md_present = true;
                memcpy(to_add->md, md, sizeof(*md));
        } else {
                to_add->md_present = false;
        }

        list_append(&to_add->link, list);

error:
        return rc;
}

static void free_svc_id_linked(struct svc_id_linked *p)
{
        if (p->md_present)
                free(p->md);
        free(p);
}

static void free_svc_id_list(list_t *list)
{
        struct svc_id_linked *dev_id;
        while (!list_empty(list)) {
                dev_id = list_pop(list, struct svc_id_linked, link);
                free_svc_id_linked(dev_id);
        }
}

static errno_t hr_fill_disk_part_svcs_list(list_t *list)
{
        errno_t rc;
        size_t disk_count;
        service_id_t *disk_svcs = NULL;
        vbd_t *vbd = NULL;

        rc = vbd_create(&vbd);
        if (rc != EOK)
                goto error;

        rc = vbd_get_disks(vbd, &disk_svcs, &disk_count);
        if (rc != EOK)
                goto error;

        for (size_t i = 0; i < disk_count; i++) {
                vbd_disk_info_t disk_info;
                rc = vbd_disk_info(vbd, disk_svcs[i], &disk_info);
                if (rc != EOK)
                        goto error;

                if (disk_info.ltype == lt_none) {
                        rc = hr_add_svc_linked_to_list(list, disk_svcs[i], false, NULL);
                        if (rc != EOK)
                                goto error;
                } else {
                        size_t part_count;
                        service_id_t *part_ids = NULL;
                        rc = vbd_label_get_parts(vbd, disk_svcs[i], &part_ids, &part_count);
                        if (rc != EOK)
                                goto error;

                        for (size_t j = 0; j < part_count; j++) {
                                vbd_part_info_t part_info;
                                rc = vbd_part_get_info(vbd, part_ids[j], &part_info);
                                if (rc != EOK) {
                                        free(part_ids);
                                        goto error;
                                }

                                rc = hr_add_svc_linked_to_list(list,
                                    part_info.svc_id, false, NULL);
                                if (rc != EOK) {
                                        free(part_ids);
                                        goto error;
                                }
                        }

                        free(part_ids);
                }
        }

        free(disk_svcs);
        vbd_destroy(vbd);
        return EOK;
error:
        free_svc_id_list(list);
        if (disk_svcs != NULL)
                free(disk_svcs);
        vbd_destroy(vbd);

        return rc;
}

static errno_t block_init_dev_list(list_t *list)
{
        list_foreach_safe(*list, cur_link, next_link) {
                struct svc_id_linked *iter;
                iter = list_get_instance(cur_link, struct svc_id_linked, link);

                if (iter->inited)
                        continue;

                errno_t rc = block_init(iter->svc_id);

                /* already used as an extent of active volume */
                /* XXX: figure out how it is with hotspares too */
                if (rc == EEXIST) {
                        list_remove(cur_link);
                        free_svc_id_linked(iter);
                        continue;
                }

                if (rc != EOK)
                        return rc;

                iter->inited = true;
        }

        return EOK;
}

static void block_fini_dev_list(list_t *list)
{
        list_foreach(*list, link, struct svc_id_linked, iter) {
                if (iter->inited) {
                        block_fini(iter->svc_id);
                        iter->inited = false;
                }
        }
}

static errno_t hr_util_get_matching_md_svcs_list(list_t *rlist, list_t *devlist,
    service_id_t svc_id, hr_metadata_t *md_main)
{
        errno_t rc = EOK;

        list_foreach(*devlist, link, struct svc_id_linked, iter) {
                if (iter->svc_id == svc_id)
                        continue;
                void *md_block;
                hr_metadata_t md;
                rc = hr_get_metadata_block(iter->svc_id, &md_block);
                if (rc != EOK)
                        goto error;
                hr_decode_metadata_from_block(md_block, &md);

                free(md_block);

                if (!hr_valid_md_magic(&md))
                        continue;

                if (memcmp(md_main->uuid, md.uuid, HR_UUID_LEN) != 0)
                        continue;

                /*
                 * XXX: can I assume bsize and everything is fine when
                 * UUID matches?
                 */

                rc = hr_add_svc_linked_to_list(rlist, iter->svc_id, true, &md);
                if (rc != EOK)
                        goto error;
        }

        return  EOK;
error:
        free_svc_id_list(rlist);
        return rc;
}

static errno_t hr_util_assemble_from_matching_list(list_t *list)
{
        HR_DEBUG("%s()", __func__);

        errno_t rc = EOK;

        hr_metadata_t *main_md = NULL;
        size_t max_counter_val = 0;

        list_foreach(*list, link, struct svc_id_linked, iter) {
                hr_metadata_dump(iter->md);
                if (iter->md->counter >= max_counter_val) {
                        max_counter_val = iter->md->counter;
                        main_md = iter->md;
                }
        }

        assert(main_md != NULL);

        hr_volume_t *vol;
        rc = hr_create_vol_struct(&vol, (hr_level_t)main_md->level);
        if (rc != EOK)
                goto error;

        vol->nblocks = main_md->nblocks;
        vol->data_blkno = main_md->data_blkno;
        vol->truncated_blkno = main_md->truncated_blkno;
        vol->data_offset = main_md->data_offset;
        vol->counter = main_md->counter;
        vol->metadata_version = main_md->version;
        vol->extent_no = main_md->extent_no;
        vol->level = main_md->level;
        vol->layout = main_md->layout;
        vol->strip_size = main_md->strip_size;
        vol->bsize = main_md->bsize;
        memcpy(vol->devname, main_md->devname, HR_DEVNAME_LEN);

        list_foreach(*list, link, struct svc_id_linked, iter) {
                vol->extents[iter->md->index].svc_id = iter->svc_id;
                if (iter->md->counter == max_counter_val)
                        vol->extents[iter->md->index].status = HR_EXT_ONLINE;
                else
                        vol->extents[iter->md->index].status = HR_EXT_INVALID;
        }

        rc = vol->hr_ops.create(vol);
        if (rc != EOK)
                goto error;

        fibril_rwlock_write_lock(&hr_volumes_lock);

        list_foreach(hr_volumes, lvolumes, hr_volume_t, other) {
                uint8_t *our_uuid = vol->in_mem_md->uuid;
                uint8_t *other_uuid = other->in_mem_md->uuid;
                if (memcmp(our_uuid, other_uuid, HR_UUID_LEN) == 0) {
                        rc = EEXIST;
                        fibril_rwlock_write_unlock(&hr_volumes_lock);
                        goto error;
                }
        }

        /*
         * XXX: register it here
         * ... if it fails on EEXIST try different name... like + 1 on the end
         */

        list_append(&vol->lvolumes, &hr_volumes);

        fibril_rwlock_write_unlock(&hr_volumes_lock);

        return EOK;
error:
        hr_destroy_vol_struct(vol);
        return rc;
}

errno_t hr_util_try_auto_assemble(size_t *rassembled_cnt)
{
        HR_DEBUG("%s()", __func__);

        /*
         * scan partitions or disks:
         *
         * When we find a metadata block with valid
         * magic, take UUID and try to find other matching
         * UUIDs.
         *
         * We ignore extents that are a part of already
         * active volumes. (even when the counter is lower
         * on active volumes... XXX: use timestamp as initial counter value
         * when assembling, or writing dirty metadata?)
         */

        size_t asm_cnt = 0;
        errno_t rc;
        list_t dev_id_list;

        list_initialize(&dev_id_list);
        rc = hr_fill_disk_part_svcs_list(&dev_id_list);
        if (rc != EOK)
                goto error;

        rc = block_init_dev_list(&dev_id_list);
        if (rc != EOK)
                goto error;

        struct svc_id_linked *iter;
        while (!list_empty(&dev_id_list)) {
                iter = list_pop(&dev_id_list, struct svc_id_linked, link);

                printf("svc_id: %lu\n", iter->svc_id);

                void *metadata_block;
                hr_metadata_t metadata;

                rc = hr_get_metadata_block(iter->svc_id, &metadata_block);
                if (rc != EOK)
                        goto error;

                hr_decode_metadata_from_block(metadata_block, &metadata);

                free(metadata_block);

                if (!hr_valid_md_magic(&metadata)) {
                        printf("BAD magic\n");
                        block_fini(iter->svc_id);
                        free_svc_id_linked(iter);
                        continue;
                }

                hr_metadata_dump(&metadata);

                char *svc_name = NULL;
                rc = loc_service_get_name(iter->svc_id, &svc_name);
                if (rc != EOK)
                        goto error;

                HR_DEBUG("found valid metadata on %s, "
                    "will try to match other extents\n", svc_name);

                free(svc_name);

                list_t matching_svcs_list;
                list_initialize(&matching_svcs_list);

                rc = hr_util_get_matching_md_svcs_list(&matching_svcs_list,
                    &dev_id_list, iter->svc_id, &metadata);
                if (rc != EOK)
                        goto error;

                /* add current iter to list as well */
                rc = hr_add_svc_linked_to_list(&matching_svcs_list,
                    iter->svc_id, true, &metadata);
                if (rc != EOK) {
                        free_svc_id_list(&matching_svcs_list);
                        goto error;
                }

                /* remove matching list members from dev_id_list */
                list_foreach(matching_svcs_list, link, struct svc_id_linked,
                    iter2) {
                        printf("matching svc_id: %lu\n", iter2->svc_id);
                        struct svc_id_linked *to_remove;
                        list_foreach_safe(dev_id_list, cur_link, next_link) {
                                to_remove = list_get_instance(cur_link,
                                    struct svc_id_linked, link);
                                if (to_remove->svc_id == iter2->svc_id) {
                                        list_remove(cur_link);
                                        free_svc_id_linked(to_remove);
                                }
                        }
                }

                rc = hr_util_assemble_from_matching_list(&matching_svcs_list);
                switch (rc) {
                case EOK:
                        asm_cnt++;
                        break;
                case EEXIST:
                        /*
                         * A race is detected this way, because we don't want
                         * to hold the hr_volumes list lock for a long time,
                         * for all assembly attempts. XXX: discuss...
                         */
                        rc = EOK;
                        break;
                default:
                        block_fini_dev_list(&matching_svcs_list);
                        free_svc_id_list(&matching_svcs_list);
                        goto error;
                }

                free_svc_id_list(&matching_svcs_list);
        }

error:
        if (rassembled_cnt != NULL)
                *rassembled_cnt = asm_cnt;

        block_fini_dev_list(&dev_id_list);
        free_svc_id_list(&dev_id_list);

        return rc;
}

/** @}
 */