zvol.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) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
 *
 * Copyright (c) 2006-2010 Pawel Jakub Dawidek <pjd@FreeBSD.org>
 * All rights reserved.
 */

/* Portions Copyright 2010 Robert Milkowski */
/* Portions Copyright 2011 Martin Matuska <mm@FreeBSD.org> */

#include <sys/types.h>
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/errno.h>
#include <sys/uio.h>
#include <sys/bio.h>
#include <sys/buf.h>
#include <sys/kmem.h>
#include <sys/conf.h>
#include <sys/cmn_err.h>
#include <sys/stat.h>
#include <sys/zap.h>
#include <sys/spa.h>
#include <sys/zio.h>
#include <sys/dmu_traverse.h>
#include <sys/dnode.h>
#include <sys/dsl_dataset.h>
#include <sys/dsl_prop.h>
#include <sys/dkio.h>
#include <sys/byteorder.h>
#include <sys/sunddi.h>
#include <sys/dirent.h>
#include <sys/policy.h>
#include <sys/fs/zfs.h>
#include <sys/zfs_ioctl.h>
#include <sys/zil.h>
#include <sys/refcount.h>
#include <sys/zfs_znode.h>
#include <sys/zfs_rlock.h>
#include <sys/vdev_impl.h>
#include <sys/zvol.h>
#include <sys/zil_impl.h>
#include <geom/geom.h>

#include "zfs_namecheck.h"

struct g_class zfs_zvol_class = {
        .name = "ZFS::ZVOL",
        .version = G_VERSION,
};

DECLARE_GEOM_CLASS(zfs_zvol_class, zfs_zvol);

void *zfsdev_state;
static char *zvol_tag = "zvol_tag";

#define ZVOL_DUMPSIZE           "dumpsize"

static uint32_t zvol_minors;

typedef struct zvol_extent {
        list_node_t     ze_node;
        dva_t           ze_dva;         
        uint64_t        ze_nblks;       
} zvol_extent_t;

typedef struct zvol_state {
        char            zv_name[MAXPATHLEN]; 
        uint64_t        zv_volsize;     
        uint64_t        zv_volblocksize; 
        struct g_provider *zv_provider; 
        uint8_t         zv_min_bs;      
        uint8_t         zv_flags;       
        objset_t        *zv_objset;     
        uint32_t        zv_total_opens; 
        zilog_t         *zv_zilog;      
        list_t          zv_extents;     
        znode_t         zv_znode;       
        dmu_buf_t       *zv_dbuf;       
        int             zv_state;
        struct bio_queue_head zv_queue;
        struct mtx      zv_queue_mtx;   
} zvol_state_t;

/*
 * zvol specific flags
 */
#define ZVOL_RDONLY     0x1
#define ZVOL_DUMPIFIED  0x2
#define ZVOL_EXCL       0x4
#define ZVOL_WCE        0x8

int zvol_maxphys = DMU_MAX_ACCESS/2;

extern int zfs_set_prop_nvlist(const char *, zprop_source_t,
    nvlist_t *, nvlist_t **);
static int zvol_remove_zv(zvol_state_t *);
static int zvol_get_data(void *arg, lr_write_t *lr, char *buf, zio_t *zio);
static int zvol_dumpify(zvol_state_t *zv);
static int zvol_dump_fini(zvol_state_t *zv);
static int zvol_dump_init(zvol_state_t *zv, boolean_t resize);

static zvol_state_t *zvol_geom_create(const char *name);
static void zvol_geom_run(zvol_state_t *zv);
static void zvol_geom_destroy(zvol_state_t *zv);
static int zvol_geom_access(struct g_provider *pp, int acr, int acw, int ace);
static void zvol_geom_start(struct bio *bp);
static void zvol_geom_worker(void *arg);

static void
zvol_size_changed(zvol_state_t *zv)
{
#ifdef sun
        dev_t dev = makedevice(maj, min);

        VERIFY(ddi_prop_update_int64(dev, zfs_dip,
            "Size", volsize) == DDI_SUCCESS);
        VERIFY(ddi_prop_update_int64(dev, zfs_dip,
            "Nblocks", lbtodb(volsize)) == DDI_SUCCESS);

        /* Notify specfs to invalidate the cached size */
        spec_size_invalidate(dev, VBLK);
        spec_size_invalidate(dev, VCHR);
#else   /* !sun */
        struct g_provider *pp;

        pp = zv->zv_provider;
        if (pp == NULL)
                return;
        g_topology_lock();
        g_resize_provider(pp, zv->zv_volsize);
        g_topology_unlock();
#endif  /* !sun */
}

int
zvol_check_volsize(uint64_t volsize, uint64_t blocksize)
{
        if (volsize == 0)
                return (EINVAL);

        if (volsize % blocksize != 0)
                return (EINVAL);

#ifdef _ILP32
        if (volsize - 1 > SPEC_MAXOFFSET_T)
                return (EOVERFLOW);
#endif
        return (0);
}

int
zvol_check_volblocksize(uint64_t volblocksize)
{
        if (volblocksize < SPA_MINBLOCKSIZE ||
            volblocksize > SPA_MAXBLOCKSIZE ||
            !ISP2(volblocksize))
                return (EDOM);

        return (0);
}

int
zvol_get_stats(objset_t *os, nvlist_t *nv)
{
        int error;
        dmu_object_info_t doi;
        uint64_t val;

        error = zap_lookup(os, ZVOL_ZAP_OBJ, "size", 8, 1, &val);
        if (error)
                return (error);

        dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_VOLSIZE, val);

        error = dmu_object_info(os, ZVOL_OBJ, &doi);

        if (error == 0) {
                dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_VOLBLOCKSIZE,
                    doi.doi_data_block_size);
        }

        return (error);
}

static zvol_state_t *
zvol_minor_lookup(const char *name)
{
        struct g_provider *pp;
        struct g_geom *gp;
        zvol_state_t *zv = NULL;

        ASSERT(MUTEX_HELD(&spa_namespace_lock));

        g_topology_lock();
        LIST_FOREACH(gp, &zfs_zvol_class.geom, geom) {
                pp = LIST_FIRST(&gp->provider);
                if (pp == NULL)
                        continue;
                zv = pp->private;
                if (zv == NULL)
                        continue;
                if (strcmp(zv->zv_name, name) == 0)
                        break;
        }
        g_topology_unlock();

        return (gp != NULL ? zv : NULL);
}

struct maparg {
        zvol_state_t    *ma_zv;
        uint64_t        ma_blks;
};

/*ARGSUSED*/
static int
zvol_map_block(spa_t *spa, zilog_t *zilog, const blkptr_t *bp, arc_buf_t *pbuf,
    const zbookmark_t *zb, const dnode_phys_t *dnp, void *arg)
{
        struct maparg *ma = arg;
        zvol_extent_t *ze;
        int bs = ma->ma_zv->zv_volblocksize;

        if (bp == NULL || zb->zb_object != ZVOL_OBJ || zb->zb_level != 0)
                return (0);

        VERIFY3U(ma->ma_blks, ==, zb->zb_blkid);
        ma->ma_blks++;

        /* Abort immediately if we have encountered gang blocks */
        if (BP_IS_GANG(bp))
                return (EFRAGS);

        /*
         * See if the block is at the end of the previous extent.
         */
        ze = list_tail(&ma->ma_zv->zv_extents);
        if (ze &&
            DVA_GET_VDEV(BP_IDENTITY(bp)) == DVA_GET_VDEV(&ze->ze_dva) &&
            DVA_GET_OFFSET(BP_IDENTITY(bp)) ==
            DVA_GET_OFFSET(&ze->ze_dva) + ze->ze_nblks * bs) {
                ze->ze_nblks++;
                return (0);
        }

        dprintf_bp(bp, "%s", "next blkptr:");

        /* start a new extent */
        ze = kmem_zalloc(sizeof (zvol_extent_t), KM_SLEEP);
        ze->ze_dva = bp->blk_dva[0];    /* structure assignment */
        ze->ze_nblks = 1;
        list_insert_tail(&ma->ma_zv->zv_extents, ze);
        return (0);
}

static void
zvol_free_extents(zvol_state_t *zv)
{
        zvol_extent_t *ze;

        while (ze = list_head(&zv->zv_extents)) {
                list_remove(&zv->zv_extents, ze);
                kmem_free(ze, sizeof (zvol_extent_t));
        }
}

static int
zvol_get_lbas(zvol_state_t *zv)
{
        objset_t *os = zv->zv_objset;
        struct maparg   ma;
        int             err;

        ma.ma_zv = zv;
        ma.ma_blks = 0;
        zvol_free_extents(zv);

        /* commit any in-flight changes before traversing the dataset */
        txg_wait_synced(dmu_objset_pool(os), 0);
        err = traverse_dataset(dmu_objset_ds(os), 0,
            TRAVERSE_PRE | TRAVERSE_PREFETCH_METADATA, zvol_map_block, &ma);
        if (err || ma.ma_blks != (zv->zv_volsize / zv->zv_volblocksize)) {
                zvol_free_extents(zv);
                return (err ? err : EIO);
        }

        return (0);
}

/* ARGSUSED */
void
zvol_create_cb(objset_t *os, void *arg, cred_t *cr, dmu_tx_t *tx)
{
        zfs_creat_t *zct = arg;
        nvlist_t *nvprops = zct->zct_props;
        int error;
        uint64_t volblocksize, volsize;

        VERIFY(nvlist_lookup_uint64(nvprops,
            zfs_prop_to_name(ZFS_PROP_VOLSIZE), &volsize) == 0);
        if (nvlist_lookup_uint64(nvprops,
            zfs_prop_to_name(ZFS_PROP_VOLBLOCKSIZE), &volblocksize) != 0)
                volblocksize = zfs_prop_default_numeric(ZFS_PROP_VOLBLOCKSIZE);

        /*
         * These properties must be removed from the list so the generic
         * property setting step won't apply to them.
         */
        VERIFY(nvlist_remove_all(nvprops,
            zfs_prop_to_name(ZFS_PROP_VOLSIZE)) == 0);
        (void) nvlist_remove_all(nvprops,
            zfs_prop_to_name(ZFS_PROP_VOLBLOCKSIZE));

        error = dmu_object_claim(os, ZVOL_OBJ, DMU_OT_ZVOL, volblocksize,
            DMU_OT_NONE, 0, tx);
        ASSERT(error == 0);

        error = zap_create_claim(os, ZVOL_ZAP_OBJ, DMU_OT_ZVOL_PROP,
            DMU_OT_NONE, 0, tx);
        ASSERT(error == 0);

        error = zap_update(os, ZVOL_ZAP_OBJ, "size", 8, 1, &volsize, tx);
        ASSERT(error == 0);
}

static int
zvol_replay_write(zvol_state_t *zv, lr_write_t *lr, boolean_t byteswap)
{
        objset_t *os = zv->zv_objset;
        char *data = (char *)(lr + 1);  /* data follows lr_write_t */
        uint64_t offset, length;
        dmu_tx_t *tx;
        int error;

        if (byteswap)
                byteswap_uint64_array(lr, sizeof (*lr));

        offset = lr->lr_offset;
        length = lr->lr_length;

        /* If it's a dmu_sync() block, write the whole block */
        if (lr->lr_common.lrc_reclen == sizeof (lr_write_t)) {
                uint64_t blocksize = BP_GET_LSIZE(&lr->lr_blkptr);
                if (length < blocksize) {
                        offset -= offset % blocksize;
                        length = blocksize;
                }
        }

        tx = dmu_tx_create(os);
        dmu_tx_hold_write(tx, ZVOL_OBJ, offset, length);
        error = dmu_tx_assign(tx, TXG_WAIT);
        if (error) {
                dmu_tx_abort(tx);
        } else {
                dmu_write(os, ZVOL_OBJ, offset, length, data, tx);
                dmu_tx_commit(tx);
        }

        return (error);
}

/* ARGSUSED */
static int
zvol_replay_err(zvol_state_t *zv, lr_t *lr, boolean_t byteswap)
{
        return (ENOTSUP);
}

zil_replay_func_t *zvol_replay_vector[TX_MAX_TYPE] = {
        zvol_replay_err,        
        zvol_replay_err,        
        zvol_replay_err,        
        zvol_replay_err,        
        zvol_replay_err,        
        zvol_replay_err,        
        zvol_replay_err,        
        zvol_replay_err,        
        zvol_replay_err,        
        zvol_replay_write,      
        zvol_replay_err,        
        zvol_replay_err,        
        zvol_replay_err,        
        zvol_replay_err,        
        zvol_replay_err,        
        zvol_replay_err,        
        zvol_replay_err,        
        zvol_replay_err,        
        zvol_replay_err,        
        zvol_replay_err,        
};

#ifdef sun
int
zvol_name2minor(const char *name, minor_t *minor)
{
        zvol_state_t *zv;

        mutex_enter(&spa_namespace_lock);
        zv = zvol_minor_lookup(name);
        if (minor && zv)
                *minor = zv->zv_minor;
        mutex_exit(&spa_namespace_lock);
        return (zv ? 0 : -1);
}
#endif  /* sun */

int
zvol_create_minor(const char *name)
{
        zfs_soft_state_t *zs;
        zvol_state_t *zv;
        objset_t *os;
        dmu_object_info_t doi;
        uint64_t volsize;
        int error;

        ZFS_LOG(1, "Creating ZVOL %s...", name);

        mutex_enter(&spa_namespace_lock);

        if (zvol_minor_lookup(name) != NULL) {
                mutex_exit(&spa_namespace_lock);
                return (EEXIST);
        }

        /* lie and say we're read-only */
        error = dmu_objset_own(name, DMU_OST_ZVOL, B_TRUE, FTAG, &os);

        if (error) {
                mutex_exit(&spa_namespace_lock);
                return (error);
        }

#ifdef sun
        if ((minor = zfsdev_minor_alloc()) == 0) {
                dmu_objset_disown(os, FTAG);
                mutex_exit(&spa_namespace_lock);
                return (ENXIO);
        }

        if (ddi_soft_state_zalloc(zfsdev_state, minor) != DDI_SUCCESS) {
                dmu_objset_disown(os, FTAG);
                mutex_exit(&spa_namespace_lock);
                return (EAGAIN);
        }
        (void) ddi_prop_update_string(minor, zfs_dip, ZVOL_PROP_NAME,
            (char *)name);

        (void) snprintf(chrbuf, sizeof (chrbuf), "%u,raw", minor);

        if (ddi_create_minor_node(zfs_dip, chrbuf, S_IFCHR,
            minor, DDI_PSEUDO, 0) == DDI_FAILURE) {
                ddi_soft_state_free(zfsdev_state, minor);
                dmu_objset_disown(os, FTAG);
                mutex_exit(&spa_namespace_lock);
                return (EAGAIN);
        }

        (void) snprintf(blkbuf, sizeof (blkbuf), "%u", minor);

        if (ddi_create_minor_node(zfs_dip, blkbuf, S_IFBLK,
            minor, DDI_PSEUDO, 0) == DDI_FAILURE) {
                ddi_remove_minor_node(zfs_dip, chrbuf);
                ddi_soft_state_free(zfsdev_state, minor);
                dmu_objset_disown(os, FTAG);
                mutex_exit(&spa_namespace_lock);
                return (EAGAIN);
        }

        zs = ddi_get_soft_state(zfsdev_state, minor);
        zs->zss_type = ZSST_ZVOL;
        zv = zs->zss_data = kmem_zalloc(sizeof (zvol_state_t), KM_SLEEP);
#else   /* !sun */

        error = zap_lookup(os, ZVOL_ZAP_OBJ, "size", 8, 1, &volsize);
        if (error) {
                ASSERT(error == 0);
                dmu_objset_disown(os, zvol_tag);
                mutex_exit(&spa_namespace_lock);
                return (error);
        }

        DROP_GIANT();
        g_topology_lock();
        zv = zvol_geom_create(name);
        zv->zv_volsize = volsize;
        zv->zv_provider->mediasize = zv->zv_volsize;

#endif  /* !sun */

        (void) strlcpy(zv->zv_name, name, MAXPATHLEN);
        zv->zv_min_bs = DEV_BSHIFT;
        zv->zv_objset = os;
        if (dmu_objset_is_snapshot(os) || !spa_writeable(dmu_objset_spa(os)))
                zv->zv_flags |= ZVOL_RDONLY;
        mutex_init(&zv->zv_znode.z_range_lock, NULL, MUTEX_DEFAULT, NULL);
        avl_create(&zv->zv_znode.z_range_avl, zfs_range_compare,
            sizeof (rl_t), offsetof(rl_t, r_node));
        list_create(&zv->zv_extents, sizeof (zvol_extent_t),
            offsetof(zvol_extent_t, ze_node));
        /* get and cache the blocksize */
        error = dmu_object_info(os, ZVOL_OBJ, &doi);
        ASSERT(error == 0);
        zv->zv_volblocksize = doi.doi_data_block_size;

        if (spa_writeable(dmu_objset_spa(os))) {
                if (zil_replay_disable)
                        zil_destroy(dmu_objset_zil(os), B_FALSE);
                else
                        zil_replay(os, zv, zvol_replay_vector);
        }
        dmu_objset_disown(os, FTAG);
        zv->zv_objset = NULL;

        zvol_minors++;

        mutex_exit(&spa_namespace_lock);

        zvol_geom_run(zv);

        g_topology_unlock();
        PICKUP_GIANT();

        ZFS_LOG(1, "ZVOL %s created.", name);

        return (0);
}

static int
zvol_remove_zv(zvol_state_t *zv)
{
#ifdef sun
        minor_t minor = zv->zv_minor;
#endif

        ASSERT(MUTEX_HELD(&spa_namespace_lock));
        if (zv->zv_total_opens != 0)
                return (EBUSY);

        ZFS_LOG(1, "ZVOL %s destroyed.", zv->zv_name);

#ifdef sun
        (void) snprintf(nmbuf, sizeof (nmbuf), "%u,raw", minor);
        ddi_remove_minor_node(zfs_dip, nmbuf);
#endif  /* sun */

        avl_destroy(&zv->zv_znode.z_range_avl);
        mutex_destroy(&zv->zv_znode.z_range_lock);

        zvol_geom_destroy(zv);

        zvol_minors--;
        return (0);
}

int
zvol_remove_minor(const char *name)
{
        zvol_state_t *zv;
        int rc;

        mutex_enter(&spa_namespace_lock);
        if ((zv = zvol_minor_lookup(name)) == NULL) {
                mutex_exit(&spa_namespace_lock);
                return (ENXIO);
        }
        g_topology_lock();
        rc = zvol_remove_zv(zv);
        g_topology_unlock();
        mutex_exit(&spa_namespace_lock);
        return (rc);
}

int
zvol_first_open(zvol_state_t *zv)
{
        objset_t *os;
        uint64_t volsize;
        int error;
        uint64_t readonly;

        /* lie and say we're read-only */
        error = dmu_objset_own(zv->zv_name, DMU_OST_ZVOL, B_TRUE,
            zvol_tag, &os);
        if (error)
                return (error);

        error = zap_lookup(os, ZVOL_ZAP_OBJ, "size", 8, 1, &volsize);
        if (error) {
                ASSERT(error == 0);
                dmu_objset_disown(os, zvol_tag);
                return (error);
        }
        zv->zv_objset = os;
        error = dmu_bonus_hold(os, ZVOL_OBJ, zvol_tag, &zv->zv_dbuf);
        if (error) {
                dmu_objset_disown(os, zvol_tag);
                return (error);
        }
        zv->zv_volsize = volsize;
        zv->zv_zilog = zil_open(os, zvol_get_data);
        zvol_size_changed(zv);

        VERIFY(dsl_prop_get_integer(zv->zv_name, "readonly", &readonly,
            NULL) == 0);
        if (readonly || dmu_objset_is_snapshot(os) ||
            !spa_writeable(dmu_objset_spa(os)))
                zv->zv_flags |= ZVOL_RDONLY;
        else
                zv->zv_flags &= ~ZVOL_RDONLY;
        return (error);
}

void
zvol_last_close(zvol_state_t *zv)
{
        zil_close(zv->zv_zilog);
        zv->zv_zilog = NULL;

        dmu_buf_rele(zv->zv_dbuf, zvol_tag);
        zv->zv_dbuf = NULL;

        /*
         * Evict cached data
         */
        if (dsl_dataset_is_dirty(dmu_objset_ds(zv->zv_objset)) &&
            !(zv->zv_flags & ZVOL_RDONLY))
                txg_wait_synced(dmu_objset_pool(zv->zv_objset), 0);
        (void) dmu_objset_evict_dbufs(zv->zv_objset);

        dmu_objset_disown(zv->zv_objset, zvol_tag);
        zv->zv_objset = NULL;
}

#ifdef sun
int
zvol_prealloc(zvol_state_t *zv)
{
        objset_t *os = zv->zv_objset;
        dmu_tx_t *tx;
        uint64_t refd, avail, usedobjs, availobjs;
        uint64_t resid = zv->zv_volsize;
        uint64_t off = 0;

        /* Check the space usage before attempting to allocate the space */
        dmu_objset_space(os, &refd, &avail, &usedobjs, &availobjs);
        if (avail < zv->zv_volsize)
                return (ENOSPC);

        /* Free old extents if they exist */
        zvol_free_extents(zv);

        while (resid != 0) {
                int error;
                uint64_t bytes = MIN(resid, SPA_MAXBLOCKSIZE);

                tx = dmu_tx_create(os);
                dmu_tx_hold_write(tx, ZVOL_OBJ, off, bytes);
                error = dmu_tx_assign(tx, TXG_WAIT);
                if (error) {
                        dmu_tx_abort(tx);
                        (void) dmu_free_long_range(os, ZVOL_OBJ, 0, off);
                        return (error);
                }
                dmu_prealloc(os, ZVOL_OBJ, off, bytes, tx);
                dmu_tx_commit(tx);
                off += bytes;
                resid -= bytes;
        }
        txg_wait_synced(dmu_objset_pool(os), 0);

        return (0);
}
#endif  /* sun */

int
zvol_update_volsize(objset_t *os, uint64_t volsize)
{
        dmu_tx_t *tx;
        int error;

        ASSERT(MUTEX_HELD(&spa_namespace_lock));

        tx = dmu_tx_create(os);
        dmu_tx_hold_zap(tx, ZVOL_ZAP_OBJ, TRUE, NULL);
        error = dmu_tx_assign(tx, TXG_WAIT);
        if (error) {
                dmu_tx_abort(tx);
                return (error);
        }

        error = zap_update(os, ZVOL_ZAP_OBJ, "size", 8, 1,
            &volsize, tx);
        dmu_tx_commit(tx);

        if (error == 0)
                error = dmu_free_long_range(os,
                    ZVOL_OBJ, volsize, DMU_OBJECT_END);
        return (error);
}

void
zvol_remove_minors(const char *name)
{
        struct g_geom *gp, *gptmp;
        struct g_provider *pp;
        zvol_state_t *zv;
        size_t namelen;

        namelen = strlen(name);

        DROP_GIANT();
        mutex_enter(&spa_namespace_lock);
        g_topology_lock();

        LIST_FOREACH_SAFE(gp, &zfs_zvol_class.geom, geom, gptmp) {
                pp = LIST_FIRST(&gp->provider);
                if (pp == NULL)
                        continue;
                zv = pp->private;
                if (zv == NULL)
                        continue;
                if (strcmp(zv->zv_name, name) == 0 ||
                    (strncmp(zv->zv_name, name, namelen) == 0 &&
                     zv->zv_name[namelen] == '/')) {
                        (void) zvol_remove_zv(zv);
                }
        }

        g_topology_unlock();
        mutex_exit(&spa_namespace_lock);
        PICKUP_GIANT();
}

int
zvol_set_volsize(const char *name, major_t maj, uint64_t volsize)
{
        zvol_state_t *zv = NULL;
        objset_t *os;
        int error;
        dmu_object_info_t doi;
        uint64_t old_volsize = 0ULL;
        uint64_t readonly;

        mutex_enter(&spa_namespace_lock);
        zv = zvol_minor_lookup(name);
        if ((error = dmu_objset_hold(name, FTAG, &os)) != 0) {
                mutex_exit(&spa_namespace_lock);
                return (error);
        }

        if ((error = dmu_object_info(os, ZVOL_OBJ, &doi)) != 0 ||
            (error = zvol_check_volsize(volsize,
            doi.doi_data_block_size)) != 0)
                goto out;

        VERIFY(dsl_prop_get_integer(name, "readonly", &readonly,
            NULL) == 0);
        if (readonly) {
                error = EROFS;
                goto out;
        }

        error = zvol_update_volsize(os, volsize);
        /*
         * Reinitialize the dump area to the new size. If we
         * failed to resize the dump area then restore it back to
         * its original size.
         */
        if (zv && error == 0) {
#ifdef ZVOL_DUMP
                if (zv->zv_flags & ZVOL_DUMPIFIED) {
                        old_volsize = zv->zv_volsize;
                        zv->zv_volsize = volsize;
                        if ((error = zvol_dumpify(zv)) != 0 ||
                            (error = dumpvp_resize()) != 0) {
                                (void) zvol_update_volsize(os, old_volsize);
                                zv->zv_volsize = old_volsize;
                                error = zvol_dumpify(zv);
                        }
                }
#endif  /* ZVOL_DUMP */
                if (error == 0) {
                        zv->zv_volsize = volsize;
                        zvol_size_changed(zv);
                }
        }

#ifdef sun
        /*
         * Generate a LUN expansion event.
         */
        if (zv && error == 0) {
                sysevent_id_t eid;
                nvlist_t *attr;
                char *physpath = kmem_zalloc(MAXPATHLEN, KM_SLEEP);

                (void) snprintf(physpath, MAXPATHLEN, "%s%u", ZVOL_PSEUDO_DEV,
                    zv->zv_minor);

                VERIFY(nvlist_alloc(&attr, NV_UNIQUE_NAME, KM_SLEEP) == 0);
                VERIFY(nvlist_add_string(attr, DEV_PHYS_PATH, physpath) == 0);

                (void) ddi_log_sysevent(zfs_dip, SUNW_VENDOR, EC_DEV_STATUS,
                    ESC_DEV_DLE, attr, &eid, DDI_SLEEP);

                nvlist_free(attr);
                kmem_free(physpath, MAXPATHLEN);
        }
#endif  /* sun */

out:
        dmu_objset_rele(os, FTAG);

        mutex_exit(&spa_namespace_lock);

        return (error);
}

/*ARGSUSED*/
static int
zvol_open(struct g_provider *pp, int flag, int count)
{
        zvol_state_t *zv;
        int err = 0;
        boolean_t locked = B_FALSE;

        /*
         * Protect against recursively entering spa_namespace_lock
         * when spa_open() is used for a pool on a (local) ZVOL(s).
         * This is needed since we replaced upstream zfsdev_state_lock
         * with spa_namespace_lock in the ZVOL code.
         * We are using the same trick as spa_open().
         * Note that calls in zvol_first_open which need to resolve
         * pool name to a spa object will enter spa_open()
         * recursively, but that function already has all the
         * necessary protection.
         */
        if (!MUTEX_HELD(&spa_namespace_lock)) {
                mutex_enter(&spa_namespace_lock);
                locked = B_TRUE;
        }

        zv = pp->private;
        if (zv == NULL) {
                if (locked)
                        mutex_exit(&spa_namespace_lock);
                return (ENXIO);
        }

        if (zv->zv_total_opens == 0)
                err = zvol_first_open(zv);
        if (err) {
                if (locked)
                        mutex_exit(&spa_namespace_lock);
                return (err);
        }
        if ((flag & FWRITE) && (zv->zv_flags & ZVOL_RDONLY)) {
                err = EROFS;
                goto out;
        }
        if (zv->zv_flags & ZVOL_EXCL) {
                err = EBUSY;
                goto out;
        }
#ifdef FEXCL
        if (flag & FEXCL) {
                if (zv->zv_total_opens != 0) {
                        err = EBUSY;
                        goto out;
                }
                zv->zv_flags |= ZVOL_EXCL;
        }
#endif

        zv->zv_total_opens += count;
        if (locked)
                mutex_exit(&spa_namespace_lock);

        return (err);
out:
        if (zv->zv_total_opens == 0)
                zvol_last_close(zv);
        if (locked)
                mutex_exit(&spa_namespace_lock);
        return (err);
}

/*ARGSUSED*/
static int
zvol_close(struct g_provider *pp, int flag, int count)
{
        zvol_state_t *zv;
        int error = 0;
        boolean_t locked = B_FALSE;

        /* See comment in zvol_open(). */
        if (!MUTEX_HELD(&spa_namespace_lock)) {
                mutex_enter(&spa_namespace_lock);
                locked = B_TRUE;
        }

        zv = pp->private;
        if (zv == NULL) {
                if (locked)
                        mutex_exit(&spa_namespace_lock);
                return (ENXIO);
        }

        if (zv->zv_flags & ZVOL_EXCL) {
                ASSERT(zv->zv_total_opens == 1);
                zv->zv_flags &= ~ZVOL_EXCL;
        }

        /*
         * If the open count is zero, this is a spurious close.
         * That indicates a bug in the kernel / DDI framework.
         */
        ASSERT(zv->zv_total_opens != 0);

        /*
         * You may get multiple opens, but only one close.
         */
        zv->zv_total_opens -= count;

        if (zv->zv_total_opens == 0)
                zvol_last_close(zv);

        if (locked)
                mutex_exit(&spa_namespace_lock);
        return (error);
}

static void
zvol_get_done(zgd_t *zgd, int error)
{
        if (zgd->zgd_db)
                dmu_buf_rele(zgd->zgd_db, zgd);

        zfs_range_unlock(zgd->zgd_rl);

        if (error == 0 && zgd->zgd_bp)
                zil_add_block(zgd->zgd_zilog, zgd->zgd_bp);

        kmem_free(zgd, sizeof (zgd_t));
}

static int
zvol_get_data(void *arg, lr_write_t *lr, char *buf, zio_t *zio)
{
        zvol_state_t *zv = arg;
        objset_t *os = zv->zv_objset;
        uint64_t object = ZVOL_OBJ;
        uint64_t offset = lr->lr_offset;
        uint64_t size = lr->lr_length;  /* length of user data */
        blkptr_t *bp = &lr->lr_blkptr;
        dmu_buf_t *db;
        zgd_t *zgd;
        int error;

        ASSERT(zio != NULL);
        ASSERT(size != 0);

        zgd = kmem_zalloc(sizeof (zgd_t), KM_SLEEP);
        zgd->zgd_zilog = zv->zv_zilog;
        zgd->zgd_rl = zfs_range_lock(&zv->zv_znode, offset, size, RL_READER);

        /*
         * Write records come in two flavors: immediate and indirect.
         * For small writes it's cheaper to store the data with the
         * log record (immediate); for large writes it's cheaper to
         * sync the data and get a pointer to it (indirect) so that
         * we don't have to write the data twice.
         */
        if (buf != NULL) {      /* immediate write */
                error = dmu_read(os, object, offset, size, buf,
                    DMU_READ_NO_PREFETCH);
        } else {
                size = zv->zv_volblocksize;
                offset = P2ALIGN(offset, size);
                error = dmu_buf_hold(os, object, offset, zgd, &db,
                    DMU_READ_NO_PREFETCH);
                if (error == 0) {
                        zgd->zgd_db = db;
                        zgd->zgd_bp = bp;

                        ASSERT(db->db_offset == offset);
                        ASSERT(db->db_size == size);

                        error = dmu_sync(zio, lr->lr_common.lrc_txg,
                            zvol_get_done, zgd);

                        if (error == 0)
                                return (0);
                }
        }

        zvol_get_done(zgd, error);

        return (error);
}

ssize_t zvol_immediate_write_sz = 32768;
static void
zvol_log_write(zvol_state_t *zv, dmu_tx_t *tx, offset_t off, ssize_t resid,
    boolean_t sync)
{
        uint32_t blocksize = zv->zv_volblocksize;
        zilog_t *zilog = zv->zv_zilog;
        boolean_t slogging;
        ssize_t immediate_write_sz;

        if (zil_replaying(zilog, tx))
                return;

        immediate_write_sz = (zilog->zl_logbias == ZFS_LOGBIAS_THROUGHPUT)
            ? 0 : zvol_immediate_write_sz;

        slogging = spa_has_slogs(zilog->zl_spa) &&
            (zilog->zl_logbias == ZFS_LOGBIAS_LATENCY);

        while (resid) {
                itx_t *itx;
                lr_write_t *lr;
                ssize_t len;
                itx_wr_state_t write_state;

                /*
                 * Unlike zfs_log_write() we can be called with
                 * upto DMU_MAX_ACCESS/2 (5MB) writes.
                 */
                if (blocksize > immediate_write_sz && !slogging &&
                    resid >= blocksize && off % blocksize == 0) {
                        write_state = WR_INDIRECT; /* uses dmu_sync */
                        len = blocksize;
                } else if (sync) {
                        write_state = WR_COPIED;
                        len = MIN(ZIL_MAX_LOG_DATA, resid);
                } else {
                        write_state = WR_NEED_COPY;
                        len = MIN(ZIL_MAX_LOG_DATA, resid);
                }

                itx = zil_itx_create(TX_WRITE, sizeof (*lr) +
                    (write_state == WR_COPIED ? len : 0));
                lr = (lr_write_t *)&itx->itx_lr;
                if (write_state == WR_COPIED && dmu_read(zv->zv_objset,
                    ZVOL_OBJ, off, len, lr + 1, DMU_READ_NO_PREFETCH) != 0) {
                        zil_itx_destroy(itx);
                        itx = zil_itx_create(TX_WRITE, sizeof (*lr));
                        lr = (lr_write_t *)&itx->itx_lr;
                        write_state = WR_NEED_COPY;
                }

                itx->itx_wr_state = write_state;
                if (write_state == WR_NEED_COPY)
                        itx->itx_sod += len;
                lr->lr_foid = ZVOL_OBJ;
                lr->lr_offset = off;
                lr->lr_length = len;
                lr->lr_blkoff = 0;
                BP_ZERO(&lr->lr_blkptr);

                itx->itx_private = zv;
                itx->itx_sync = sync;

                zil_itx_assign(zilog, itx, tx);

                off += len;
                resid -= len;
        }
}

#ifdef sun
static int
zvol_dumpio_vdev(vdev_t *vd, void *addr, uint64_t offset, uint64_t size,
    boolean_t doread, boolean_t isdump)
{
        vdev_disk_t *dvd;
        int c;
        int numerrors = 0;

        for (c = 0; c < vd->vdev_children; c++) {
                ASSERT(vd->vdev_ops == &vdev_mirror_ops ||
                    vd->vdev_ops == &vdev_replacing_ops ||
                    vd->vdev_ops == &vdev_spare_ops);
                int err = zvol_dumpio_vdev(vd->vdev_child[c],
                    addr, offset, size, doread, isdump);
                if (err != 0) {
                        numerrors++;
                } else if (doread) {
                        break;
                }
        }

        if (!vd->vdev_ops->vdev_op_leaf)
                return (numerrors < vd->vdev_children ? 0 : EIO);

        if (doread && !vdev_readable(vd))
                return (EIO);
        else if (!doread && !vdev_writeable(vd))
                return (EIO);

        dvd = vd->vdev_tsd;
        ASSERT3P(dvd, !=, NULL);
        offset += VDEV_LABEL_START_SIZE;

        if (ddi_in_panic() || isdump) {
                ASSERT(!doread);
                if (doread)
                        return (EIO);
                return (ldi_dump(dvd->vd_lh, addr, lbtodb(offset),
                    lbtodb(size)));
        } else {
                return (vdev_disk_physio(dvd->vd_lh, addr, size, offset,
                    doread ? B_READ : B_WRITE));
        }
}

static int
zvol_dumpio(zvol_state_t *zv, void *addr, uint64_t offset, uint64_t size,
    boolean_t doread, boolean_t isdump)
{
        vdev_t *vd;
        int error;
        zvol_extent_t *ze;
        spa_t *spa = dmu_objset_spa(zv->zv_objset);

        /* Must be sector aligned, and not stradle a block boundary. */
        if (P2PHASE(offset, DEV_BSIZE) || P2PHASE(size, DEV_BSIZE) ||
            P2BOUNDARY(offset, size, zv->zv_volblocksize)) {
                return (EINVAL);
        }
        ASSERT(size <= zv->zv_volblocksize);

        /* Locate the extent this belongs to */
        ze = list_head(&zv->zv_extents);
        while (offset >= ze->ze_nblks * zv->zv_volblocksize) {
                offset -= ze->ze_nblks * zv->zv_volblocksize;
                ze = list_next(&zv->zv_extents, ze);
        }

        if (!ddi_in_panic())
                spa_config_enter(spa, SCL_STATE, FTAG, RW_READER);

        vd = vdev_lookup_top(spa, DVA_GET_VDEV(&ze->ze_dva));
        offset += DVA_GET_OFFSET(&ze->ze_dva);
        error = zvol_dumpio_vdev(vd, addr, offset, size, doread, isdump);

        if (!ddi_in_panic())
                spa_config_exit(spa, SCL_STATE, FTAG);

        return (error);
}
#endif  /* sun */

int
zvol_strategy(struct bio *bp)
{
        zvol_state_t *zv = bp->bio_to->private;
        uint64_t off, volsize;
        size_t resid;
        char *addr;
        objset_t *os;
        rl_t *rl;
        int error = 0;
        boolean_t doread = (bp->bio_cmd == BIO_READ);
        boolean_t sync;

        if (zv == NULL) {
                g_io_deliver(bp, ENXIO);
                return (0);
        }

        if (bp->bio_cmd != BIO_READ && (zv->zv_flags & ZVOL_RDONLY)) {
                g_io_deliver(bp, EROFS);
                return (0);
        }

        off = bp->bio_offset;
        volsize = zv->zv_volsize;

        os = zv->zv_objset;
        ASSERT(os != NULL);

        addr = bp->bio_data;
        resid = bp->bio_length;

        if (resid > 0 && (off < 0 || off >= volsize)) {
                g_io_deliver(bp, EIO);
                return (0);
        }

        sync = !doread && zv->zv_objset->os_sync == ZFS_SYNC_ALWAYS;

        /*
         * There must be no buffer changes when doing a dmu_sync() because
         * we can't change the data whilst calculating the checksum.
         */
        rl = zfs_range_lock(&zv->zv_znode, off, resid,
            doread ? RL_READER : RL_WRITER);

        while (resid != 0 && off < volsize) {
                size_t size = MIN(resid, zvol_maxphys);
                if (doread) {
                        error = dmu_read(os, ZVOL_OBJ, off, size, addr,
                            DMU_READ_PREFETCH);
                } else {
                        dmu_tx_t *tx = dmu_tx_create(os);
                        dmu_tx_hold_write(tx, ZVOL_OBJ, off, size);
                        error = dmu_tx_assign(tx, TXG_WAIT);
                        if (error) {
                                dmu_tx_abort(tx);
                        } else {
                                dmu_write(os, ZVOL_OBJ, off, size, addr, tx);
                                zvol_log_write(zv, tx, off, size, sync);
                                dmu_tx_commit(tx);
                        }
                }
                if (error) {
                        /* convert checksum errors into IO errors */
                        if (error == ECKSUM)
                                error = EIO;
                        break;
                }
                off += size;
                addr += size;
                resid -= size;
        }
        zfs_range_unlock(rl);

        bp->bio_completed = bp->bio_length - resid;
        if (bp->bio_completed < bp->bio_length)
                bp->bio_error = (off > volsize ? EINVAL : error);

        if (sync)
                zil_commit(zv->zv_zilog, ZVOL_OBJ);
        g_io_deliver(bp, 0);

        return (0);
}

#ifdef sun

void
zvol_minphys(struct buf *bp)
{
        if (bp->b_bcount > zvol_maxphys)
                bp->b_bcount = zvol_maxphys;
}

int
zvol_dump(dev_t dev, caddr_t addr, daddr_t blkno, int nblocks)
{
        minor_t minor = getminor(dev);
        zvol_state_t *zv;
        int error = 0;
        uint64_t size;
        uint64_t boff;
        uint64_t resid;

        zv = zfsdev_get_soft_state(minor, ZSST_ZVOL);
        if (zv == NULL)
                return (ENXIO);

        boff = ldbtob(blkno);
        resid = ldbtob(nblocks);

        VERIFY3U(boff + resid, <=, zv->zv_volsize);

        while (resid) {
                size = MIN(resid, P2END(boff, zv->zv_volblocksize) - boff);
                error = zvol_dumpio(zv, addr, boff, size, B_FALSE, B_TRUE);
                if (error)
                        break;
                boff += size;
                addr += size;
                resid -= size;
        }

        return (error);
}

/*ARGSUSED*/
int
zvol_read(dev_t dev, uio_t *uio, cred_t *cr)
{
        minor_t minor = getminor(dev);
        zvol_state_t *zv;
        uint64_t volsize;
        rl_t *rl;
        int error = 0;

        zv = zfsdev_get_soft_state(minor, ZSST_ZVOL);
        if (zv == NULL)
                return (ENXIO);

        volsize = zv->zv_volsize;
        if (uio->uio_resid > 0 &&
            (uio->uio_loffset < 0 || uio->uio_loffset >= volsize))
                return (EIO);

        if (zv->zv_flags & ZVOL_DUMPIFIED) {
                error = physio(zvol_strategy, NULL, dev, B_READ,
                    zvol_minphys, uio);
                return (error);
        }

        rl = zfs_range_lock(&zv->zv_znode, uio->uio_loffset, uio->uio_resid,
            RL_READER);
        while (uio->uio_resid > 0 && uio->uio_loffset < volsize) {
                uint64_t bytes = MIN(uio->uio_resid, DMU_MAX_ACCESS >> 1);

                /* don't read past the end */
                if (bytes > volsize - uio->uio_loffset)
                        bytes = volsize - uio->uio_loffset;

                error =  dmu_read_uio(zv->zv_objset, ZVOL_OBJ, uio, bytes);
                if (error) {
                        /* convert checksum errors into IO errors */
                        if (error == ECKSUM)
                                error = EIO;
                        break;
                }
        }
        zfs_range_unlock(rl);
        return (error);
}

/*ARGSUSED*/
int
zvol_write(dev_t dev, uio_t *uio, cred_t *cr)
{
        minor_t minor = getminor(dev);
        zvol_state_t *zv;
        uint64_t volsize;
        rl_t *rl;
        int error = 0;
        boolean_t sync;

        zv = zfsdev_get_soft_state(minor, ZSST_ZVOL);
        if (zv == NULL)
                return (ENXIO);

        volsize = zv->zv_volsize;
        if (uio->uio_resid > 0 &&
            (uio->uio_loffset < 0 || uio->uio_loffset >= volsize))
                return (EIO);

        if (zv->zv_flags & ZVOL_DUMPIFIED) {
                error = physio(zvol_strategy, NULL, dev, B_WRITE,
                    zvol_minphys, uio);
                return (error);
        }

        sync = !(zv->zv_flags & ZVOL_WCE) ||
            (zv->zv_objset->os_sync == ZFS_SYNC_ALWAYS);

        rl = zfs_range_lock(&zv->zv_znode, uio->uio_loffset, uio->uio_resid,
            RL_WRITER);
        while (uio->uio_resid > 0 && uio->uio_loffset < volsize) {
                uint64_t bytes = MIN(uio->uio_resid, DMU_MAX_ACCESS >> 1);
                uint64_t off = uio->uio_loffset;
                dmu_tx_t *tx = dmu_tx_create(zv->zv_objset);

                if (bytes > volsize - off)      /* don't write past the end */
                        bytes = volsize - off;

                dmu_tx_hold_write(tx, ZVOL_OBJ, off, bytes);
                error = dmu_tx_assign(tx, TXG_WAIT);
                if (error) {
                        dmu_tx_abort(tx);
                        break;
                }
                error = dmu_write_uio_dbuf(zv->zv_dbuf, uio, bytes, tx);
                if (error == 0)
                        zvol_log_write(zv, tx, off, bytes, sync);
                dmu_tx_commit(tx);

                if (error)
                        break;
        }
        zfs_range_unlock(rl);
        if (sync)
                zil_commit(zv->zv_zilog, ZVOL_OBJ);
        return (error);
}

int
zvol_getefi(void *arg, int flag, uint64_t vs, uint8_t bs)
{
        struct uuid uuid = EFI_RESERVED;
        efi_gpe_t gpe = { 0 };
        uint32_t crc;
        dk_efi_t efi;
        int length;
        char *ptr;

        if (ddi_copyin(arg, &efi, sizeof (dk_efi_t), flag))
                return (EFAULT);
        ptr = (char *)(uintptr_t)efi.dki_data_64;
        length = efi.dki_length;
        /*
         * Some clients may attempt to request a PMBR for the
         * zvol.  Currently this interface will return EINVAL to
         * such requests.  These requests could be supported by
         * adding a check for lba == 0 and consing up an appropriate
         * PMBR.
         */
        if (efi.dki_lba < 1 || efi.dki_lba > 2 || length <= 0)
                return (EINVAL);

        gpe.efi_gpe_StartingLBA = LE_64(34ULL);
        gpe.efi_gpe_EndingLBA = LE_64((vs >> bs) - 1);
        UUID_LE_CONVERT(gpe.efi_gpe_PartitionTypeGUID, uuid);

        if (efi.dki_lba == 1) {
                efi_gpt_t gpt = { 0 };

                gpt.efi_gpt_Signature = LE_64(EFI_SIGNATURE);
                gpt.efi_gpt_Revision = LE_32(EFI_VERSION_CURRENT);
                gpt.efi_gpt_HeaderSize = LE_32(sizeof (gpt));
                gpt.efi_gpt_MyLBA = LE_64(1ULL);
                gpt.efi_gpt_FirstUsableLBA = LE_64(34ULL);
                gpt.efi_gpt_LastUsableLBA = LE_64((vs >> bs) - 1);
                gpt.efi_gpt_PartitionEntryLBA = LE_64(2ULL);
                gpt.efi_gpt_NumberOfPartitionEntries = LE_32(1);
                gpt.efi_gpt_SizeOfPartitionEntry =
                    LE_32(sizeof (efi_gpe_t));
                CRC32(crc, &gpe, sizeof (gpe), -1U, crc32_table);
                gpt.efi_gpt_PartitionEntryArrayCRC32 = LE_32(~crc);
                CRC32(crc, &gpt, sizeof (gpt), -1U, crc32_table);
                gpt.efi_gpt_HeaderCRC32 = LE_32(~crc);
                if (ddi_copyout(&gpt, ptr, MIN(sizeof (gpt), length),
                    flag))
                        return (EFAULT);
                ptr += sizeof (gpt);
                length -= sizeof (gpt);
        }
        if (length > 0 && ddi_copyout(&gpe, ptr, MIN(sizeof (gpe),
            length), flag))
                return (EFAULT);
        return (0);
}

int
zvol_get_volume_params(minor_t minor, uint64_t *blksize,
    uint64_t *max_xfer_len, void **minor_hdl, void **objset_hdl, void **zil_hdl,
    void **rl_hdl, void **bonus_hdl)
{
        zvol_state_t *zv;

        zv = zfsdev_get_soft_state(minor, ZSST_ZVOL);
        if (zv == NULL)
                return (ENXIO);
        if (zv->zv_flags & ZVOL_DUMPIFIED)
                return (ENXIO);

        ASSERT(blksize && max_xfer_len && minor_hdl &&
            objset_hdl && zil_hdl && rl_hdl && bonus_hdl);

        *blksize = zv->zv_volblocksize;
        *max_xfer_len = (uint64_t)zvol_maxphys;
        *minor_hdl = zv;
        *objset_hdl = zv->zv_objset;
        *zil_hdl = zv->zv_zilog;
        *rl_hdl = &zv->zv_znode;
        *bonus_hdl = zv->zv_dbuf;
        return (0);
}

uint64_t
zvol_get_volume_size(void *minor_hdl)
{
        zvol_state_t *zv = minor_hdl;

        return (zv->zv_volsize);
}

int
zvol_get_volume_wce(void *minor_hdl)
{
        zvol_state_t *zv = minor_hdl;

        return ((zv->zv_flags & ZVOL_WCE) ? 1 : 0);
}

void
zvol_log_write_minor(void *minor_hdl, dmu_tx_t *tx, offset_t off, ssize_t resid,
    boolean_t sync)
{
        zvol_state_t *zv = minor_hdl;

        zvol_log_write(zv, tx, off, resid, sync);
}
/*ARGSUSED*/
int
zvol_ioctl(dev_t dev, int cmd, intptr_t arg, int flag, cred_t *cr, int *rvalp)
{
        zvol_state_t *zv;
        struct dk_cinfo dki;
        struct dk_minfo dkm;
        struct dk_callback *dkc;
        int error = 0;
        rl_t *rl;

        mutex_enter(&spa_namespace_lock);

        zv = zfsdev_get_soft_state(getminor(dev), ZSST_ZVOL);

        if (zv == NULL) {
                mutex_exit(&spa_namespace_lock);
                return (ENXIO);
        }
        ASSERT(zv->zv_total_opens > 0);

        switch (cmd) {

        case DKIOCINFO:
                bzero(&dki, sizeof (dki));
                (void) strcpy(dki.dki_cname, "zvol");
                (void) strcpy(dki.dki_dname, "zvol");
                dki.dki_ctype = DKC_UNKNOWN;
                dki.dki_unit = getminor(dev);
                dki.dki_maxtransfer = 1 << (SPA_MAXBLOCKSHIFT - zv->zv_min_bs);
                mutex_exit(&spa_namespace_lock);
                if (ddi_copyout(&dki, (void *)arg, sizeof (dki), flag))
                        error = EFAULT;
                return (error);

        case DKIOCGMEDIAINFO:
                bzero(&dkm, sizeof (dkm));
                dkm.dki_lbsize = 1U << zv->zv_min_bs;
                dkm.dki_capacity = zv->zv_volsize >> zv->zv_min_bs;
                dkm.dki_media_type = DK_UNKNOWN;
                mutex_exit(&spa_namespace_lock);
                if (ddi_copyout(&dkm, (void *)arg, sizeof (dkm), flag))
                        error = EFAULT;
                return (error);

        case DKIOCGETEFI:
                {
                        uint64_t vs = zv->zv_volsize;
                        uint8_t bs = zv->zv_min_bs;

                        mutex_exit(&spa_namespace_lock);
                        error = zvol_getefi((void *)arg, flag, vs, bs);
                        return (error);
                }

        case DKIOCFLUSHWRITECACHE:
                dkc = (struct dk_callback *)arg;
                mutex_exit(&spa_namespace_lock);
                zil_commit(zv->zv_zilog, ZVOL_OBJ);
                if ((flag & FKIOCTL) && dkc != NULL && dkc->dkc_callback) {
                        (*dkc->dkc_callback)(dkc->dkc_cookie, error);
                        error = 0;
                }
                return (error);

        case DKIOCGETWCE:
                {
                        int wce = (zv->zv_flags & ZVOL_WCE) ? 1 : 0;
                        if (ddi_copyout(&wce, (void *)arg, sizeof (int),
                            flag))
                                error = EFAULT;
                        break;
                }
        case DKIOCSETWCE:
                {
                        int wce;
                        if (ddi_copyin((void *)arg, &wce, sizeof (int),
                            flag)) {
                                error = EFAULT;
                                break;
                        }
                        if (wce) {
                                zv->zv_flags |= ZVOL_WCE;
                                mutex_exit(&spa_namespace_lock);
                        } else {
                                zv->zv_flags &= ~ZVOL_WCE;
                                mutex_exit(&spa_namespace_lock);
                                zil_commit(zv->zv_zilog, ZVOL_OBJ);
                        }
                        return (0);
                }

        case DKIOCGGEOM:
        case DKIOCGVTOC:
                /*
                 * commands using these (like prtvtoc) expect ENOTSUP
                 * since we're emulating an EFI label
                 */
                error = ENOTSUP;
                break;

        case DKIOCDUMPINIT:
                rl = zfs_range_lock(&zv->zv_znode, 0, zv->zv_volsize,
                    RL_WRITER);
                error = zvol_dumpify(zv);
                zfs_range_unlock(rl);
                break;

        case DKIOCDUMPFINI:
                if (!(zv->zv_flags & ZVOL_DUMPIFIED))
                        break;
                rl = zfs_range_lock(&zv->zv_znode, 0, zv->zv_volsize,
                    RL_WRITER);
                error = zvol_dump_fini(zv);
                zfs_range_unlock(rl);
                break;

        default:
                error = ENOTTY;
                break;

        }
        mutex_exit(&spa_namespace_lock);
        return (error);
}
#endif  /* sun */

int
zvol_busy(void)
{
        return (zvol_minors != 0);
}

void
zvol_init(void)
{
        VERIFY(ddi_soft_state_init(&zfsdev_state, sizeof (zfs_soft_state_t),
            1) == 0);
        ZFS_LOG(1, "ZVOL Initialized.");
}

void
zvol_fini(void)
{
        ddi_soft_state_fini(&zfsdev_state);
        ZFS_LOG(1, "ZVOL Deinitialized.");
}

#ifdef sun
static int
zvol_dump_init(zvol_state_t *zv, boolean_t resize)
{
        dmu_tx_t *tx;
        int error = 0;
        objset_t *os = zv->zv_objset;
        nvlist_t *nv = NULL;
        uint64_t version = spa_version(dmu_objset_spa(zv->zv_objset));

        ASSERT(MUTEX_HELD(&spa_namespace_lock));
        error = dmu_free_long_range(zv->zv_objset, ZVOL_OBJ, 0,
            DMU_OBJECT_END);
        /* wait for dmu_free_long_range to actually free the blocks */
        txg_wait_synced(dmu_objset_pool(zv->zv_objset), 0);

        tx = dmu_tx_create(os);
        dmu_tx_hold_zap(tx, ZVOL_ZAP_OBJ, TRUE, NULL);
        dmu_tx_hold_bonus(tx, ZVOL_OBJ);
        error = dmu_tx_assign(tx, TXG_WAIT);
        if (error) {
                dmu_tx_abort(tx);
                return (error);
        }

        /*
         * If we are resizing the dump device then we only need to
         * update the refreservation to match the newly updated
         * zvolsize. Otherwise, we save off the original state of the
         * zvol so that we can restore them if the zvol is ever undumpified.
         */
        if (resize) {
                error = zap_update(os, ZVOL_ZAP_OBJ,
                    zfs_prop_to_name(ZFS_PROP_REFRESERVATION), 8, 1,
                    &zv->zv_volsize, tx);
        } else {
                uint64_t checksum, compress, refresrv, vbs, dedup;

                error = dsl_prop_get_integer(zv->zv_name,
                    zfs_prop_to_name(ZFS_PROP_COMPRESSION), &compress, NULL);
                error = error ? error : dsl_prop_get_integer(zv->zv_name,
                    zfs_prop_to_name(ZFS_PROP_CHECKSUM), &checksum, NULL);
                error = error ? error : dsl_prop_get_integer(zv->zv_name,
                    zfs_prop_to_name(ZFS_PROP_REFRESERVATION), &refresrv, NULL);
                error = error ? error : dsl_prop_get_integer(zv->zv_name,
                    zfs_prop_to_name(ZFS_PROP_VOLBLOCKSIZE), &vbs, NULL);
                if (version >= SPA_VERSION_DEDUP) {
                        error = error ? error :
                            dsl_prop_get_integer(zv->zv_name,
                            zfs_prop_to_name(ZFS_PROP_DEDUP), &dedup, NULL);
                }

                error = error ? error : zap_update(os, ZVOL_ZAP_OBJ,
                    zfs_prop_to_name(ZFS_PROP_COMPRESSION), 8, 1,
                    &compress, tx);
                error = error ? error : zap_update(os, ZVOL_ZAP_OBJ,
                    zfs_prop_to_name(ZFS_PROP_CHECKSUM), 8, 1, &checksum, tx);
                error = error ? error : zap_update(os, ZVOL_ZAP_OBJ,
                    zfs_prop_to_name(ZFS_PROP_REFRESERVATION), 8, 1,
                    &refresrv, tx);
                error = error ? error : zap_update(os, ZVOL_ZAP_OBJ,
                    zfs_prop_to_name(ZFS_PROP_VOLBLOCKSIZE), 8, 1,
                    &vbs, tx);
                error = error ? error : dmu_object_set_blocksize(
                    os, ZVOL_OBJ, SPA_MAXBLOCKSIZE, 0, tx);
                if (version >= SPA_VERSION_DEDUP) {
                        error = error ? error : zap_update(os, ZVOL_ZAP_OBJ,
                            zfs_prop_to_name(ZFS_PROP_DEDUP), 8, 1,
                            &dedup, tx);
                }
                if (error == 0)
                        zv->zv_volblocksize = SPA_MAXBLOCKSIZE;
        }
        dmu_tx_commit(tx);

        /*
         * We only need update the zvol's property if we are initializing
         * the dump area for the first time.
         */
        if (!resize) {
                VERIFY(nvlist_alloc(&nv, NV_UNIQUE_NAME, KM_SLEEP) == 0);
                VERIFY(nvlist_add_uint64(nv,
                    zfs_prop_to_name(ZFS_PROP_REFRESERVATION), 0) == 0);
                VERIFY(nvlist_add_uint64(nv,
                    zfs_prop_to_name(ZFS_PROP_COMPRESSION),
                    ZIO_COMPRESS_OFF) == 0);
                VERIFY(nvlist_add_uint64(nv,
                    zfs_prop_to_name(ZFS_PROP_CHECKSUM),
                    ZIO_CHECKSUM_OFF) == 0);
                if (version >= SPA_VERSION_DEDUP) {
                        VERIFY(nvlist_add_uint64(nv,
                            zfs_prop_to_name(ZFS_PROP_DEDUP),
                            ZIO_CHECKSUM_OFF) == 0);
                }

                error = zfs_set_prop_nvlist(zv->zv_name, ZPROP_SRC_LOCAL,
                    nv, NULL);
                nvlist_free(nv);

                if (error)
                        return (error);
        }

        /* Allocate the space for the dump */
        error = zvol_prealloc(zv);
        return (error);
}

static int
zvol_dumpify(zvol_state_t *zv)
{
        int error = 0;
        uint64_t dumpsize = 0;
        dmu_tx_t *tx;
        objset_t *os = zv->zv_objset;

        if (zv->zv_flags & ZVOL_RDONLY)
                return (EROFS);

        if (zap_lookup(zv->zv_objset, ZVOL_ZAP_OBJ, ZVOL_DUMPSIZE,
            8, 1, &dumpsize) != 0 || dumpsize != zv->zv_volsize) {
                boolean_t resize = (dumpsize > 0) ? B_TRUE : B_FALSE;

                if ((error = zvol_dump_init(zv, resize)) != 0) {
                        (void) zvol_dump_fini(zv);
                        return (error);
                }
        }

        /*
         * Build up our lba mapping.
         */
        error = zvol_get_lbas(zv);
        if (error) {
                (void) zvol_dump_fini(zv);
                return (error);
        }

        tx = dmu_tx_create(os);
        dmu_tx_hold_zap(tx, ZVOL_ZAP_OBJ, TRUE, NULL);
        error = dmu_tx_assign(tx, TXG_WAIT);
        if (error) {
                dmu_tx_abort(tx);
                (void) zvol_dump_fini(zv);
                return (error);
        }

        zv->zv_flags |= ZVOL_DUMPIFIED;
        error = zap_update(os, ZVOL_ZAP_OBJ, ZVOL_DUMPSIZE, 8, 1,
            &zv->zv_volsize, tx);
        dmu_tx_commit(tx);

        if (error) {
                (void) zvol_dump_fini(zv);
                return (error);
        }

        txg_wait_synced(dmu_objset_pool(os), 0);
        return (0);
}

static int
zvol_dump_fini(zvol_state_t *zv)
{
        dmu_tx_t *tx;
        objset_t *os = zv->zv_objset;
        nvlist_t *nv;
        int error = 0;
        uint64_t checksum, compress, refresrv, vbs, dedup;
        uint64_t version = spa_version(dmu_objset_spa(zv->zv_objset));

        /*
         * Attempt to restore the zvol back to its pre-dumpified state.
         * This is a best-effort attempt as it's possible that not all
         * of these properties were initialized during the dumpify process
         * (i.e. error during zvol_dump_init).
         */

        tx = dmu_tx_create(os);
        dmu_tx_hold_zap(tx, ZVOL_ZAP_OBJ, TRUE, NULL);
        error = dmu_tx_assign(tx, TXG_WAIT);
        if (error) {
                dmu_tx_abort(tx);
                return (error);
        }
        (void) zap_remove(os, ZVOL_ZAP_OBJ, ZVOL_DUMPSIZE, tx);
        dmu_tx_commit(tx);

        (void) zap_lookup(zv->zv_objset, ZVOL_ZAP_OBJ,
            zfs_prop_to_name(ZFS_PROP_CHECKSUM), 8, 1, &checksum);
        (void) zap_lookup(zv->zv_objset, ZVOL_ZAP_OBJ,
            zfs_prop_to_name(ZFS_PROP_COMPRESSION), 8, 1, &compress);
        (void) zap_lookup(zv->zv_objset, ZVOL_ZAP_OBJ,
            zfs_prop_to_name(ZFS_PROP_REFRESERVATION), 8, 1, &refresrv);
        (void) zap_lookup(zv->zv_objset, ZVOL_ZAP_OBJ,
            zfs_prop_to_name(ZFS_PROP_VOLBLOCKSIZE), 8, 1, &vbs);

        VERIFY(nvlist_alloc(&nv, NV_UNIQUE_NAME, KM_SLEEP) == 0);
        (void) nvlist_add_uint64(nv,
            zfs_prop_to_name(ZFS_PROP_CHECKSUM), checksum);
        (void) nvlist_add_uint64(nv,
            zfs_prop_to_name(ZFS_PROP_COMPRESSION), compress);
        (void) nvlist_add_uint64(nv,
            zfs_prop_to_name(ZFS_PROP_REFRESERVATION), refresrv);
        if (version >= SPA_VERSION_DEDUP &&
            zap_lookup(zv->zv_objset, ZVOL_ZAP_OBJ,
            zfs_prop_to_name(ZFS_PROP_DEDUP), 8, 1, &dedup) == 0) {
                (void) nvlist_add_uint64(nv,
                    zfs_prop_to_name(ZFS_PROP_DEDUP), dedup);
        }
        (void) zfs_set_prop_nvlist(zv->zv_name, ZPROP_SRC_LOCAL,
            nv, NULL);
        nvlist_free(nv);

        zvol_free_extents(zv);
        zv->zv_flags &= ~ZVOL_DUMPIFIED;
        (void) dmu_free_long_range(os, ZVOL_OBJ, 0, DMU_OBJECT_END);
        /* wait for dmu_free_long_range to actually free the blocks */
        txg_wait_synced(dmu_objset_pool(zv->zv_objset), 0);
        tx = dmu_tx_create(os);
        dmu_tx_hold_bonus(tx, ZVOL_OBJ);
        error = dmu_tx_assign(tx, TXG_WAIT);
        if (error) {
                dmu_tx_abort(tx);
                return (error);
        }
        if (dmu_object_set_blocksize(os, ZVOL_OBJ, vbs, 0, tx) == 0)
                zv->zv_volblocksize = vbs;
        dmu_tx_commit(tx);

        return (0);
}
#endif  /* sun */

static zvol_state_t *
zvol_geom_create(const char *name)
{
        struct g_provider *pp;
        struct g_geom *gp;
        zvol_state_t *zv;

        gp = g_new_geomf(&zfs_zvol_class, "zfs::zvol::%s", name);
        gp->start = zvol_geom_start;
        gp->access = zvol_geom_access;
        pp = g_new_providerf(gp, "%s/%s", ZVOL_DRIVER, name);
        pp->sectorsize = DEV_BSIZE;

        zv = kmem_zalloc(sizeof(*zv), KM_SLEEP);
        zv->zv_provider = pp;
        zv->zv_state = 0;
        bioq_init(&zv->zv_queue);
        mtx_init(&zv->zv_queue_mtx, "zvol", NULL, MTX_DEF);

        pp->private = zv;

        return (zv);
}

static void
zvol_geom_run(zvol_state_t *zv)
{
        struct g_provider *pp;

        pp = zv->zv_provider;
        g_error_provider(pp, 0);

        kproc_kthread_add(zvol_geom_worker, zv, &zfsproc, NULL, 0, 0,
            "zfskern", "zvol %s", pp->name + sizeof(ZVOL_DRIVER));
}

static void
zvol_geom_destroy(zvol_state_t *zv)
{
        struct g_provider *pp;

        g_topology_assert();

        mtx_lock(&zv->zv_queue_mtx);
        zv->zv_state = 1;
        wakeup_one(&zv->zv_queue);
        while (zv->zv_state != 2)
                msleep(&zv->zv_state, &zv->zv_queue_mtx, 0, "zvol:w", 0);
        mtx_destroy(&zv->zv_queue_mtx);

        pp = zv->zv_provider;
        zv->zv_provider = NULL;
        pp->private = NULL;
        g_wither_geom(pp->geom, ENXIO);

        kmem_free(zv, sizeof(*zv));
}

static int
zvol_geom_access(struct g_provider *pp, int acr, int acw, int ace)
{
        int count, error, flags;

        g_topology_assert();

        /*
         * To make it easier we expect either open or close, but not both
         * at the same time.
         */
        KASSERT((acr >= 0 && acw >= 0 && ace >= 0) ||
            (acr <= 0 && acw <= 0 && ace <= 0),
            ("Unsupported access request to %s (acr=%d, acw=%d, ace=%d).",
            pp->name, acr, acw, ace));

        if (pp->private == NULL) {
                if (acr <= 0 && acw <= 0 && ace <= 0)
                        return (0);
                return (pp->error);
        }

        /*
         * We don't pass FEXCL flag to zvol_open()/zvol_close() if ace != 0,
         * because GEOM already handles that and handles it a bit differently.
         * GEOM allows for multiple read/exclusive consumers and ZFS allows
         * only one exclusive consumer, no matter if it is reader or writer.
         * I like better the way GEOM works so I'll leave it for GEOM to
         * decide what to do.
         */

        count = acr + acw + ace;
        if (count == 0)
                return (0);

        flags = 0;
        if (acr != 0 || ace != 0)
                flags |= FREAD;
        if (acw != 0)
                flags |= FWRITE;

        g_topology_unlock();
        if (count > 0)
                error = zvol_open(pp, flags, count);
        else
                error = zvol_close(pp, flags, -count);
        g_topology_lock();
        return (error);
}

static void
zvol_geom_start(struct bio *bp)
{
        zvol_state_t *zv;
        boolean_t first;

        switch (bp->bio_cmd) {
        case BIO_READ:
        case BIO_WRITE:
        case BIO_FLUSH:
                zv = bp->bio_to->private;
                ASSERT(zv != NULL);
                mtx_lock(&zv->zv_queue_mtx);
                first = (bioq_first(&zv->zv_queue) == NULL);
                bioq_insert_tail(&zv->zv_queue, bp);
                mtx_unlock(&zv->zv_queue_mtx);
                if (first)
                        wakeup_one(&zv->zv_queue);
                break;
        case BIO_GETATTR:
        case BIO_DELETE:
        default:
                g_io_deliver(bp, EOPNOTSUPP);
                break;
        }
}

static void
zvol_geom_worker(void *arg)
{
        zvol_state_t *zv;
        struct bio *bp;

        thread_lock(curthread);
        sched_prio(curthread, PRIBIO);
        thread_unlock(curthread);

        zv = arg;
        for (;;) {
                mtx_lock(&zv->zv_queue_mtx);
                bp = bioq_takefirst(&zv->zv_queue);
                if (bp == NULL) {
                        if (zv->zv_state == 1) {
                                zv->zv_state = 2;
                                wakeup(&zv->zv_state);
                                mtx_unlock(&zv->zv_queue_mtx);
                                kthread_exit();
                        }
                        msleep(&zv->zv_queue, &zv->zv_queue_mtx, PRIBIO | PDROP,
                            "zvol:io", 0);
                        continue;
                }
                mtx_unlock(&zv->zv_queue_mtx);
                switch (bp->bio_cmd) {
                case BIO_FLUSH:
                        zil_commit(zv->zv_zilog, ZVOL_OBJ);
                        g_io_deliver(bp, 0);
                        break;
                case BIO_READ:
                case BIO_WRITE:
                        zvol_strategy(bp);
                        break;
                }
        }
}

extern boolean_t dataset_name_hidden(const char *name);

static int
zvol_create_snapshots(objset_t *os, const char *name)
{
        uint64_t cookie, obj;
        char *sname;
        int error, len;

        cookie = obj = 0;
        sname = kmem_alloc(MAXPATHLEN, KM_SLEEP);

        (void) dmu_objset_find(name, dmu_objset_prefetch, NULL,
            DS_FIND_SNAPSHOTS);

        for (;;) {
                len = snprintf(sname, MAXPATHLEN, "%s@", name);
                if (len >= MAXPATHLEN) {
                        dmu_objset_rele(os, FTAG);
                        error = ENAMETOOLONG;
                        break;
                }

                error = dmu_snapshot_list_next(os, MAXPATHLEN - len,
                    sname + len, &obj, &cookie, NULL);
                if (error != 0) {
                        if (error == ENOENT)
                                error = 0;
                        break;
                }

                if ((error = zvol_create_minor(sname)) != 0) {
                        printf("ZFS WARNING: Unable to create ZVOL %s (error=%d).\n",
                            sname, error);
                        break;
                }
        }

        kmem_free(sname, MAXPATHLEN);
        return (error);
}

int
zvol_create_minors(const char *name)
{
        uint64_t cookie;
        objset_t *os;
        char *osname, *p;
        int error, len;

        if (dataset_name_hidden(name))
                return (0);

        if ((error = dmu_objset_hold(name, FTAG, &os)) != 0) {
                printf("ZFS WARNING: Unable to put hold on %s (error=%d).\n",
                    name, error);
                return (error);
        }
        if (dmu_objset_type(os) == DMU_OST_ZVOL) {
                if ((error = zvol_create_minor(name)) == 0)
                        error = zvol_create_snapshots(os, name);
                else {
                        printf("ZFS WARNING: Unable to create ZVOL %s (error=%d).\n",
                            name, error);
                }
                dmu_objset_rele(os, FTAG);
                return (error);
        }
        if (dmu_objset_type(os) != DMU_OST_ZFS) {
                dmu_objset_rele(os, FTAG);
                return (0);
        }

        osname = kmem_alloc(MAXPATHLEN, KM_SLEEP);
        if (snprintf(osname, MAXPATHLEN, "%s/", name) >= MAXPATHLEN) {
                dmu_objset_rele(os, FTAG);
                kmem_free(osname, MAXPATHLEN);
                return (ENOENT);
        }
        p = osname + strlen(osname);
        len = MAXPATHLEN - (p - osname);

        /* Prefetch the datasets. */
        cookie = 0;
        while (dmu_dir_list_next(os, len, p, NULL, &cookie) == 0) {
                if (!dataset_name_hidden(osname))
                        (void) dmu_objset_prefetch(osname, NULL);
        }

        cookie = 0;
        while (dmu_dir_list_next(os, MAXPATHLEN - (p - osname), p, NULL,
            &cookie) == 0) {
                dmu_objset_rele(os, FTAG);
                (void)zvol_create_minors(osname);
                if ((error = dmu_objset_hold(name, FTAG, &os)) != 0) {
                        printf("ZFS WARNING: Unable to put hold on %s (error=%d).\n",
                            name, error);
                        return (error);
                }
        }

        dmu_objset_rele(os, FTAG);
        kmem_free(osname, MAXPATHLEN);
        return (0);
}

static void
zvol_rename_minor(struct g_geom *gp, const char *newname)
{
        struct g_provider *pp;
        zvol_state_t *zv;

        ASSERT(MUTEX_HELD(&spa_namespace_lock));
        g_topology_assert();

        pp = LIST_FIRST(&gp->provider);
        ASSERT(pp != NULL);
        zv = pp->private;
        ASSERT(zv != NULL);

        zv->zv_provider = NULL;
        g_wither_provider(pp, ENXIO);

        pp = g_new_providerf(gp, "%s/%s", ZVOL_DRIVER, newname);
        pp->sectorsize = DEV_BSIZE;
        pp->mediasize = zv->zv_volsize;
        pp->private = zv;
        zv->zv_provider = pp;
        strlcpy(zv->zv_name, newname, sizeof(zv->zv_name));
        g_error_provider(pp, 0);
}

void
zvol_rename_minors(const char *oldname, const char *newname)
{
        char name[MAXPATHLEN];
        struct g_provider *pp;
        struct g_geom *gp;
        size_t oldnamelen, newnamelen;
        zvol_state_t *zv;
        char *namebuf;

        oldnamelen = strlen(oldname);
        newnamelen = strlen(newname);

        DROP_GIANT();
        mutex_enter(&spa_namespace_lock);
        g_topology_lock();

        LIST_FOREACH(gp, &zfs_zvol_class.geom, geom) {
                pp = LIST_FIRST(&gp->provider);
                if (pp == NULL)
                        continue;
                zv = pp->private;
                if (zv == NULL)
                        continue;
                if (strcmp(zv->zv_name, oldname) == 0) {
                        zvol_rename_minor(gp, newname);
                } else if (strncmp(zv->zv_name, oldname, oldnamelen) == 0 &&
                    (zv->zv_name[oldnamelen] == '/' ||
                     zv->zv_name[oldnamelen] == '@')) {
                        snprintf(name, sizeof(name), "%s%c%s", newname,
                            zv->zv_name[oldnamelen],
                            zv->zv_name + oldnamelen + 1);
                        zvol_rename_minor(gp, name);
                }
        }

        g_topology_unlock();
        mutex_exit(&spa_namespace_lock);
        PICKUP_GIANT();
}