vdev_geom.c

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/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright (c) 2006 Pawel Jakub Dawidek <pjd@FreeBSD.org>
 * All rights reserved.
 *
 * Portions Copyright (c) 2012 Martin Matuska <mm@FreeBSD.org>
 */

#include <sys/zfs_context.h>
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/bio.h>
#include <sys/disk.h>
#include <sys/spa.h>
#include <sys/spa_impl.h>
#include <sys/vdev_impl.h>
#include <sys/fs/zfs.h>
#include <sys/zio.h>
#include <geom/geom.h>
#include <geom/geom_int.h>

struct g_class zfs_vdev_class = {
        .name = "ZFS::VDEV",
        .version = G_VERSION,
};

DECLARE_GEOM_CLASS(zfs_vdev_class, zfs_vdev);

SYSCTL_DECL(_vfs_zfs_vdev);
static int vdev_geom_bio_flush_disable = 0;
TUNABLE_INT("vfs.zfs.vdev.bio_flush_disable", &vdev_geom_bio_flush_disable);
SYSCTL_INT(_vfs_zfs_vdev, OID_AUTO, bio_flush_disable, CTLFLAG_RW,
    &vdev_geom_bio_flush_disable, 0, "Disable BIO_FLUSH");
static int vdev_geom_bio_delete_disable = 0;
TUNABLE_INT("vfs.zfs.vdev.bio_delete_disable", &vdev_geom_bio_delete_disable);
SYSCTL_INT(_vfs_zfs_vdev, OID_AUTO, bio_delete_disable, CTLFLAG_RW,
    &vdev_geom_bio_delete_disable, 0, "Disable BIO_DELETE");

static void
vdev_geom_orphan(struct g_consumer *cp)
{
        vdev_t *vd;

        g_topology_assert();

        vd = cp->private;
        if (vd == NULL) {
                /* Vdev close in progress.  Ignore the event. */
                return;
        }

        /*
         * Orphan callbacks occur from the GEOM event thread.
         * Concurrent with this call, new I/O requests may be
         * working their way through GEOM about to find out
         * (only once executed by the g_down thread) that we've
         * been orphaned from our disk provider.  These I/Os
         * must be retired before we can detach our consumer.
         * This is most easily achieved by acquiring the
         * SPA ZIO configuration lock as a writer, but doing
         * so with the GEOM topology lock held would cause
         * a lock order reversal.  Instead, rely on the SPA's
         * async removal support to invoke a close on this
         * vdev once it is safe to do so.
         */
        zfs_post_remove(vd->vdev_spa, vd);
        vd->vdev_remove_wanted = B_TRUE;
        spa_async_request(vd->vdev_spa, SPA_ASYNC_REMOVE);
}

static void
vdev_geom_attrchanged(struct g_consumer *cp, const char *attr)
{
        vdev_t *vd;
        spa_t *spa;
        char *physpath;
        int error, physpath_len;

        g_topology_assert();

        if (strcmp(attr, "GEOM::physpath") != 0)
                return;

        if (g_access(cp, 1, 0, 0) != 0)
                return;

        /*
         * Record/Update physical path information for this device.
         */
        vd = cp->private;
        spa = vd->vdev_spa;
        physpath_len = MAXPATHLEN;
        physpath = g_malloc(physpath_len, M_WAITOK|M_ZERO);
        error = g_io_getattr("GEOM::physpath", cp, &physpath_len, physpath);
        g_access(cp, -1, 0, 0);
        if (error == 0) {
                char *old_physpath;

                old_physpath = vd->vdev_physpath;
                vd->vdev_physpath = spa_strdup(physpath);
                spa_async_request(spa, SPA_ASYNC_CONFIG_UPDATE);

                if (old_physpath != NULL) {
                        int held_lock;

                        held_lock = spa_config_held(spa, SCL_STATE, RW_WRITER);
                        if (held_lock == 0) {
                                g_topology_unlock();
                                spa_config_enter(spa, SCL_STATE, FTAG,
                                    RW_WRITER);
                        }

                        spa_strfree(old_physpath);

                        if (held_lock == 0) {
                                spa_config_exit(spa, SCL_STATE, FTAG);
                                g_topology_lock();
                        }
                }
        }
        g_free(physpath);
}

static struct g_consumer *
vdev_geom_attach(struct g_provider *pp, vdev_t *vd)
{
        struct g_geom *gp;
        struct g_consumer *cp;
        int error;

        g_topology_assert();

        ZFS_LOG(1, "Attaching to %s.", pp->name);
        /* Do we have geom already? No? Create one. */
        LIST_FOREACH(gp, &zfs_vdev_class.geom, geom) {
                if (gp->flags & G_GEOM_WITHER)
                        continue;
                if (strcmp(gp->name, "zfs::vdev") != 0)
                        continue;
                break;
        }
        if (gp == NULL) {
                gp = g_new_geomf(&zfs_vdev_class, "zfs::vdev");
                gp->orphan = vdev_geom_orphan;
                gp->attrchanged = vdev_geom_attrchanged;
                cp = g_new_consumer(gp);
                error = g_attach(cp, pp);
                if (error != 0) {
                        printf("%s(%d): g_attach failed: %d\n", __func__,
                               __LINE__, error);
                        g_wither_geom(gp, ENXIO);
                        return (NULL);
                }
                error = g_access(cp, 1, 0, 1);
                if (error != 0) {
                        printf("%s(%d): g_access failed: %d\n", __func__,
                               __LINE__, error);
                        g_wither_geom(gp, ENXIO);
                        return (NULL);
                }
                ZFS_LOG(1, "Created geom and consumer for %s.", pp->name);
        } else {
                /* Check if we are already connected to this provider. */
                LIST_FOREACH(cp, &gp->consumer, consumer) {
                        if (cp->provider == pp) {
                                ZFS_LOG(1, "Provider %s already in use by ZFS. "
                                    "Failing attach.", pp->name);
                                return (NULL);
                        }
                }
                cp = g_new_consumer(gp);
                error = g_attach(cp, pp);
                if (error != 0) {
                        printf("%s(%d): g_attach failed: %d\n",
                               __func__, __LINE__, error);
                        g_destroy_consumer(cp);
                        return (NULL);
                }
                error = g_access(cp, 1, 0, 1);
                if (error != 0) {
                        printf("%s(%d): g_access failed: %d\n",
                               __func__, __LINE__, error);
                        g_detach(cp);
                        g_destroy_consumer(cp);
                        return (NULL);
                }
                ZFS_LOG(1, "Created consumer for %s.", pp->name);
        }

        cp->private = vd;
        vd->vdev_tsd = cp;

        /* Fetch initial physical path information for this device. */
        vdev_geom_attrchanged(cp, "GEOM::physpath");
        
        return (cp);
}

static void
vdev_geom_close_locked(vdev_t *vd)
{
        struct g_geom *gp;
        struct g_consumer *cp;

        g_topology_assert();

        cp = vd->vdev_tsd;
        if (cp == NULL)
                return;

        ZFS_LOG(1, "Closing access to %s.", cp->provider->name);
        KASSERT(vd->vdev_tsd == cp, ("%s: vdev_tsd is not cp", __func__));
        KASSERT(cp->private == vd, ("%s: cp->private is not vd", __func__));
        vd->vdev_tsd = NULL;
        cp->private = NULL;

        gp = cp->geom;
        g_access(cp, -1, 0, -1);
        /* Destroy consumer on last close. */
        if (cp->acr == 0 && cp->ace == 0) {
                ZFS_LOG(1, "Destroyed consumer to %s.", cp->provider->name);
                if (cp->acw > 0)
                        g_access(cp, 0, -cp->acw, 0);
                g_detach(cp);
                g_destroy_consumer(cp);
        }
        /* Destroy geom if there are no consumers left. */
        if (LIST_EMPTY(&gp->consumer)) {
                ZFS_LOG(1, "Destroyed geom %s.", gp->name);
                g_wither_geom(gp, ENXIO);
        }
}

static void
nvlist_get_guids(nvlist_t *list, uint64_t *pguid, uint64_t *vguid)
{
        nvpair_t *elem = NULL;

        *vguid = 0;
        *pguid = 0;
        while ((elem = nvlist_next_nvpair(list, elem)) != NULL) {
                if (nvpair_type(elem) != DATA_TYPE_UINT64)
                        continue;

                if (strcmp(nvpair_name(elem), ZPOOL_CONFIG_POOL_GUID) == 0) {
                        VERIFY(nvpair_value_uint64(elem, pguid) == 0);
                } else if (strcmp(nvpair_name(elem), ZPOOL_CONFIG_GUID) == 0) {
                        VERIFY(nvpair_value_uint64(elem, vguid) == 0);
                }

                if (*pguid != 0 && *vguid != 0)
                        break;
        }
}

static int
vdev_geom_io(struct g_consumer *cp, int cmd, void *data, off_t offset, off_t size)
{
        struct bio *bp;
        u_char *p;
        off_t off, maxio;
        int error;

        ASSERT((offset % cp->provider->sectorsize) == 0);
        ASSERT((size % cp->provider->sectorsize) == 0);

        bp = g_alloc_bio();
        off = offset;
        offset += size;
        p = data;
        maxio = MAXPHYS - (MAXPHYS % cp->provider->sectorsize);
        error = 0;

        for (; off < offset; off += maxio, p += maxio, size -= maxio) {
                bzero(bp, sizeof(*bp));
                bp->bio_cmd = cmd;
                bp->bio_done = NULL;
                bp->bio_offset = off;
                bp->bio_length = MIN(size, maxio);
                bp->bio_data = p;
                g_io_request(bp, cp);
                error = biowait(bp, "vdev_geom_io");
                if (error != 0)
                        break;
        }

        g_destroy_bio(bp);
        return (error);
}

static int
vdev_geom_read_config(struct g_consumer *cp, nvlist_t **config)
{
        struct g_provider *pp;
        vdev_label_t *label;
        char *p, *buf;
        size_t buflen;
        uint64_t psize, state, txg;
        off_t offset, size;
        int error, l, len;

        g_topology_assert_not();

        pp = cp->provider;
        ZFS_LOG(1, "Reading config from %s...", pp->name);

        psize = pp->mediasize;
        psize = P2ALIGN(psize, (uint64_t)sizeof(vdev_label_t));

        size = sizeof(*label) + pp->sectorsize -
            ((sizeof(*label) - 1) % pp->sectorsize) - 1;

        label = kmem_alloc(size, KM_SLEEP);
        buflen = sizeof(label->vl_vdev_phys.vp_nvlist);

        *config = NULL;
        for (l = 0; l < VDEV_LABELS; l++) {

                offset = vdev_label_offset(psize, l, 0);
                if ((offset % pp->sectorsize) != 0)
                        continue;

                if (vdev_geom_io(cp, BIO_READ, label, offset, size) != 0)
                        continue;
                buf = label->vl_vdev_phys.vp_nvlist;

                if (nvlist_unpack(buf, buflen, config, 0) != 0)
                        continue;

                if (nvlist_lookup_uint64(*config, ZPOOL_CONFIG_POOL_STATE,
                    &state) != 0 || state == POOL_STATE_DESTROYED ||
                    state > POOL_STATE_L2CACHE) {
                        nvlist_free(*config);
                        *config = NULL;
                        continue;
                }

                if (state != POOL_STATE_SPARE && state != POOL_STATE_L2CACHE &&
                    (nvlist_lookup_uint64(*config, ZPOOL_CONFIG_POOL_TXG,
                    &txg) != 0 || txg == 0)) {
                        nvlist_free(*config);
                        *config = NULL;
                        continue;
                }

                break;
        }

        kmem_free(label, size);
        return (*config == NULL ? ENOENT : 0);
}

static int
vdev_geom_check_config(nvlist_t *config, const char *name, uint64_t *best_txg)
{
        uint64_t vdev_guid;
        uint64_t txg;
        char *pname;

        if (nvlist_lookup_string(config, ZPOOL_CONFIG_POOL_NAME, &pname) != 0 ||
            strcmp(pname, name) != 0)
                return (ENOENT);

        ZFS_LOG(1, "found pool: %s", pname);

        txg = 0;
        nvlist_lookup_uint64(config, ZPOOL_CONFIG_POOL_TXG, &txg);
        if (txg <= *best_txg)
                return (ENOENT);
        *best_txg = txg;
        ZFS_LOG(1, "txg: %ju", (uintmax_t)*best_txg);

        return (0);
}

static int
vdev_geom_attach_taster(struct g_consumer *cp, struct g_provider *pp)
{
        int error;

        if (pp->flags & G_PF_WITHER)
                return (EINVAL);
        if (pp->sectorsize > VDEV_PAD_SIZE || !ISP2(pp->sectorsize))
                return (EINVAL);
        g_attach(cp, pp);
        error = g_access(cp, 1, 0, 0);
        if (error != 0)
                g_detach(cp);
        return (error);
}

static void
vdev_geom_detach_taster(struct g_consumer *cp)
{
        g_access(cp, -1, 0, 0);
        g_detach(cp);
}

static void
vdev_geom_taste_orphan(struct g_consumer *cp)
{

        KASSERT(1 == 0, ("%s called while tasting %s.", __func__,
            cp->provider->name));
}

int
vdev_geom_read_pool_label(const char *name, nvlist_t **config)
{
        struct g_class *mp;
        struct g_geom *gp, *zgp;
        struct g_provider *pp;
        struct g_consumer *zcp;
        nvlist_t *vdev_cfg;
        uint64_t best_txg;
        int error;

        DROP_GIANT();
        g_topology_lock();

        zgp = g_new_geomf(&zfs_vdev_class, "zfs::vdev::taste");
        /* This orphan function should be never called. */
        zgp->orphan = vdev_geom_taste_orphan;
        zcp = g_new_consumer(zgp);

        best_txg = 0;
        *config = NULL;
        LIST_FOREACH(mp, &g_classes, class) {
                if (mp == &zfs_vdev_class)
                        continue;
                LIST_FOREACH(gp, &mp->geom, geom) {
                        if (gp->flags & G_GEOM_WITHER)
                                continue;
                        LIST_FOREACH(pp, &gp->provider, provider) {
                                if (pp->flags & G_PF_WITHER)
                                        continue;
                                if (vdev_geom_attach_taster(zcp, pp) != 0)
                                        continue;
                                g_topology_unlock();
                                error = vdev_geom_read_config(zcp, &vdev_cfg);
                                g_topology_lock();
                                vdev_geom_detach_taster(zcp);
                                if (error)
                                        continue;
                                ZFS_LOG(1, "successfully read vdev config");

                                error = vdev_geom_check_config(vdev_cfg, name,
                                    &best_txg);
                                if (error != 0) {
                                        nvlist_free(vdev_cfg);
                                        continue;
                                }
                                nvlist_free(*config);
                                *config = vdev_cfg;
                        }
                }
        }

        g_destroy_consumer(zcp);
        g_destroy_geom(zgp);
        g_topology_unlock();
        PICKUP_GIANT();
        return (*config == NULL ? ENOENT : 0);
}

static void
vdev_geom_read_guids(struct g_consumer *cp, uint64_t *pguid, uint64_t *vguid)
{
        nvlist_t *config;

        g_topology_assert_not();
        *pguid = 0;
        *vguid = 0;

        if (vdev_geom_read_config(cp, &config) == 0) {
                nvlist_get_guids(config, pguid, vguid);
                nvlist_free(config);
        }
}

static struct g_consumer *
vdev_geom_attach_by_guids(vdev_t *vd)
{
        struct g_class *mp;
        struct g_geom *gp, *zgp;
        struct g_provider *pp;
        struct g_consumer *cp, *zcp;
        uint64_t pguid;
        uint64_t vguid;

        g_topology_assert();

        zgp = g_new_geomf(&zfs_vdev_class, "zfs::vdev::taste");
        /* This orphan function should be never called. */
        zgp->orphan = vdev_geom_taste_orphan;
        zcp = g_new_consumer(zgp);

        cp = NULL;
        LIST_FOREACH(mp, &g_classes, class) {
                if (mp == &zfs_vdev_class)
                        continue;
                LIST_FOREACH(gp, &mp->geom, geom) {
                        if (gp->flags & G_GEOM_WITHER)
                                continue;
                        LIST_FOREACH(pp, &gp->provider, provider) {
                                if (vdev_geom_attach_taster(zcp, pp) != 0)
                                        continue;
                                g_topology_unlock();
                                vdev_geom_read_guids(zcp, &pguid, &vguid);
                                g_topology_lock();
                                vdev_geom_detach_taster(zcp);
                                if (pguid != spa_guid(vd->vdev_spa) ||
                                    vguid != vd->vdev_guid)
                                        continue;
                                cp = vdev_geom_attach(pp, vd);
                                if (cp == NULL) {
                                        printf("ZFS WARNING: Unable to attach "
                                            "to %s.\n", pp->name);
                                        continue;
                                }
                                break;
                        }
                        if (cp != NULL)
                                break;
                }
                if (cp != NULL)
                        break;
        }
end:
        g_destroy_consumer(zcp);
        g_destroy_geom(zgp);
        return (cp);
}

static struct g_consumer *
vdev_geom_open_by_guids(vdev_t *vd)
{
        struct g_consumer *cp;
        char *buf;
        size_t len;

        g_topology_assert();

        ZFS_LOG(1, "Searching by guids [%ju:%ju].",
            (uintmax_t)spa_guid(vd->vdev_spa), (uintmax_t)vd->vdev_guid);
        cp = vdev_geom_attach_by_guids(vd);
        if (cp != NULL) {
                len = strlen(cp->provider->name) + strlen("/dev/") + 1;
                buf = kmem_alloc(len, KM_SLEEP);

                snprintf(buf, len, "/dev/%s", cp->provider->name);
                spa_strfree(vd->vdev_path);
                vd->vdev_path = buf;

                ZFS_LOG(1, "Attach by guids [%ju:%ju] succeeded, provider %s.",
                    (uintmax_t)spa_guid(vd->vdev_spa),
                    (uintmax_t)vd->vdev_guid, vd->vdev_path);
        } else {
                ZFS_LOG(1, "Search by guids [%ju:%ju] failed.",
                    (uintmax_t)spa_guid(vd->vdev_spa),
                    (uintmax_t)vd->vdev_guid);
        }

        return (cp);
}

static struct g_consumer *
vdev_geom_open_by_path(vdev_t *vd, int check_guid)
{
        struct g_provider *pp;
        struct g_consumer *cp;
        uint64_t pguid, vguid;

        g_topology_assert();

        ZFS_LOG(1, "Opening by path %s%s", vd->vdev_path,
            check_guid ? " with GUID verification." : "");

        cp = NULL;
        pp = g_provider_by_name(vd->vdev_path + sizeof("/dev/") - 1);
        if (pp != NULL) {
                ZFS_LOG(1, "Found provider by name %s.", vd->vdev_path);
                cp = vdev_geom_attach(pp, vd);
                if (cp != NULL && check_guid && ISP2(pp->sectorsize) &&
                    pp->sectorsize <= VDEV_PAD_SIZE) {
                        g_topology_unlock();
                        vdev_geom_read_guids(cp, &pguid, &vguid);
                        g_topology_lock();
                        if (pguid != spa_guid(vd->vdev_spa) ||
                            vguid != vd->vdev_guid) {
                                vdev_geom_close_locked(vd);
                                cp = NULL;
                                ZFS_LOG(1, "guid mismatch for provider %s: "
                                    "%ju:%ju != %ju:%ju.", vd->vdev_path,
                                    (uintmax_t)spa_guid(vd->vdev_spa),
                                    (uintmax_t)vd->vdev_guid,
                                    (uintmax_t)pguid, (uintmax_t)vguid);
                        } else {
                                ZFS_LOG(1, "guids match for provider %s.",
                                    vd->vdev_path);
                        }
                }
        }

        return (cp);
}

static int
vdev_geom_open(vdev_t *vd, uint64_t *psize, uint64_t *max_psize,
    uint64_t *ashift)
{
        struct g_provider *pp;
        struct g_consumer *cp;
        size_t bufsize;
        int error;

        /*
         * We must have a pathname, and it must be absolute.
         */
        if (vd->vdev_path == NULL || vd->vdev_path[0] != '/') {
                vd->vdev_stat.vs_aux = VDEV_AUX_BAD_LABEL;
                return (EINVAL);
        }

        vd->vdev_tsd = NULL;

        DROP_GIANT();
        g_topology_lock();
        error = 0;

        /*
         * Try using the recorded path for this device, but only
         * accept it if its label data contains the expected GUIDs.
         */
        cp = vdev_geom_open_by_path(vd, 1);
        if (cp == NULL) {
                /*
                 * The device at vd->vdev_path doesn't have the
                 * expected GUIDs. The disks might have merely
                 * moved around so try all other GEOM providers
                 * to find one with the right GUIDs.
                 */
                cp = vdev_geom_open_by_guids(vd);
        }

        if (cp == NULL &&
            ((vd->vdev_prevstate == VDEV_STATE_UNKNOWN &&
              vd->vdev_spa->spa_load_state == SPA_LOAD_NONE) ||
             vd->vdev_spa->spa_splitting_newspa == B_TRUE)) {
                /*
                 * We are dealing with a vdev that hasn't been previosly
                 * opened (since boot), and we are not loading an
                 * existing pool configuration (e.g. this operations is
                 * an add of a vdev to new or * existing pool) or we are
                 * in the process of splitting a pool.  Find the GEOM
                 * provider by its name, ignoring GUID mismatches.
                 *
                 * XXPOLICY: It would be safer to only allow a device
                 *           that is unlabeled or labeled but missing
                 *           GUID information to be opened in this fashion.
                 */
                cp = vdev_geom_open_by_path(vd, 0);
        }

        if (cp == NULL) {
                ZFS_LOG(1, "Provider %s not found.", vd->vdev_path);
                error = ENOENT;
        } else if (cp->provider->sectorsize > VDEV_PAD_SIZE ||
            !ISP2(cp->provider->sectorsize)) {
                ZFS_LOG(1, "Provider %s has unsupported sectorsize.",
                    vd->vdev_path);
                vdev_geom_close_locked(vd);
                error = EINVAL;
                cp = NULL;
        } else if (cp->acw == 0 && (spa_mode(vd->vdev_spa) & FWRITE) != 0) {
                int i;

                for (i = 0; i < 5; i++) {
                        error = g_access(cp, 0, 1, 0);
                        if (error == 0)
                                break;
                        g_topology_unlock();
                        tsleep(vd, 0, "vdev", hz / 2);
                        g_topology_lock();
                }
                if (error != 0) {
                        printf("ZFS WARNING: Unable to open %s for writing (error=%d).\n",
                            vd->vdev_path, error);
                        vdev_geom_close_locked(vd);
                        cp = NULL;
                }
        }

        g_topology_unlock();
        PICKUP_GIANT();

        if (cp == NULL) {
                vd->vdev_stat.vs_aux = VDEV_AUX_OPEN_FAILED;
                return (error);
        }
        pp = cp->provider;

        /*
         * Determine the actual size of the device.
         */
        *max_psize = *psize = pp->mediasize;

        /*
         * Determine the device's minimum transfer size.
         */
        *ashift = highbit(MAX(pp->sectorsize, SPA_MINBLOCKSIZE)) - 1;

        /*
         * Clear the nowritecache settings, so that on a vdev_reopen()
         * we will try again.
         */
        vd->vdev_nowritecache = B_FALSE;

        return (0);
}

static void
vdev_geom_close(vdev_t *vd)
{
        g_topology_lock();
        vdev_geom_close_locked(vd);
        g_topology_unlock();
}

static void
vdev_geom_io_intr(struct bio *bp)
{
        vdev_t *vd;
        zio_t *zio;

        zio = bp->bio_caller1;
        vd = zio->io_vd;
        zio->io_error = bp->bio_error;
        if (zio->io_error == 0 && bp->bio_resid != 0)
                zio->io_error = EIO;
        if (bp->bio_cmd == BIO_FLUSH && bp->bio_error == ENOTSUP) {
                /*
                 * If we get ENOTSUP, we know that no future
                 * attempts will ever succeed.  In this case we
                 * set a persistent bit so that we don't bother
                 * with the ioctl in the future.
                 */
                vd->vdev_nowritecache = B_TRUE;
        }
        if (bp->bio_cmd == BIO_DELETE && bp->bio_error == ENOTSUP) {
                /*
                 * If we get ENOTSUP, we know that no future
                 * attempts will ever succeed.  In this case we
                 * set a persistent bit so that we don't bother
                 * with the ioctl in the future.
                 */
                vd->vdev_notrim = B_TRUE;
        }
        if (zio->io_error == EIO && !vd->vdev_remove_wanted) {
                /*
                 * If provider's error is set we assume it is being
                 * removed.
                 */
                if (bp->bio_to->error != 0) {
                        /*
                         * We post the resource as soon as possible, instead of
                         * when the async removal actually happens, because the
                         * DE is using this information to discard previous I/O
                         * errors.
                         */
                        /* XXX: zfs_post_remove() can sleep. */
                        zfs_post_remove(zio->io_spa, vd);
                        vd->vdev_remove_wanted = B_TRUE;
                        spa_async_request(zio->io_spa, SPA_ASYNC_REMOVE);
                } else if (!vd->vdev_delayed_close) {
                        vd->vdev_delayed_close = B_TRUE;
                }
        }
        g_destroy_bio(bp);
        zio_interrupt(zio);
}

static int
vdev_geom_io_start(zio_t *zio)
{
        vdev_t *vd;
        struct g_consumer *cp;
        struct bio *bp;
        int error;

        vd = zio->io_vd;

        if (zio->io_type == ZIO_TYPE_IOCTL) {
                /* XXPOLICY */
                if (!vdev_readable(vd)) {
                        zio->io_error = ENXIO;
                        return (ZIO_PIPELINE_CONTINUE);
                }

                switch (zio->io_cmd) {
                case DKIOCFLUSHWRITECACHE:
                        if (zfs_nocacheflush || vdev_geom_bio_flush_disable)
                                break;
                        if (vd->vdev_nowritecache) {
                                zio->io_error = ENOTSUP;
                                break;
                        }
                        goto sendreq;
                case DKIOCTRIM:
                        if (vdev_geom_bio_delete_disable)
                                break;
                        if (vd->vdev_notrim) {
                                zio->io_error = ENOTSUP;
                                break;
                        }
                        goto sendreq;
                default:
                        zio->io_error = ENOTSUP;
                }

                return (ZIO_PIPELINE_CONTINUE);
        }
sendreq:
        cp = vd->vdev_tsd;
        if (cp == NULL) {
                zio->io_error = ENXIO;
                return (ZIO_PIPELINE_CONTINUE);
        }
        bp = g_alloc_bio();
        bp->bio_caller1 = zio;
        switch (zio->io_type) {
        case ZIO_TYPE_READ:
        case ZIO_TYPE_WRITE:
                bp->bio_cmd = zio->io_type == ZIO_TYPE_READ ? BIO_READ : BIO_WRITE;
                bp->bio_data = zio->io_data;
                bp->bio_offset = zio->io_offset;
                bp->bio_length = zio->io_size;
                break;
        case ZIO_TYPE_IOCTL:
                switch (zio->io_cmd) {
                case DKIOCFLUSHWRITECACHE:
                        bp->bio_cmd = BIO_FLUSH;
                        bp->bio_flags |= BIO_ORDERED;
                        bp->bio_data = NULL;
                        bp->bio_offset = cp->provider->mediasize;
                        bp->bio_length = 0;
                        break;
                case DKIOCTRIM:
                        bp->bio_cmd = BIO_DELETE;
                        bp->bio_data = NULL;
                        bp->bio_offset = zio->io_offset;
                        bp->bio_length = zio->io_size;
                        break;
                }
                break;
        }
        bp->bio_done = vdev_geom_io_intr;

        g_io_request(bp, cp);

        return (ZIO_PIPELINE_STOP);
}

static void
vdev_geom_io_done(zio_t *zio)
{
}

static void
vdev_geom_hold(vdev_t *vd)
{
}

static void
vdev_geom_rele(vdev_t *vd)
{
}

vdev_ops_t vdev_geom_ops = {
        vdev_geom_open,
        vdev_geom_close,
        vdev_default_asize,
        vdev_geom_io_start,
        vdev_geom_io_done,
        NULL,
        vdev_geom_hold,
        vdev_geom_rele,
        VDEV_TYPE_DISK,         /* name of this vdev type */
        B_TRUE                  /* leaf vdev */
};