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/usr/src/uts/common/fs/zfs/zvol.c

https://bitbucket.org/osunix/osunix-gate
C | 1894 lines | 1424 code | 269 blank | 201 comment | 312 complexity | 734cd080f066608554cb4d3396308ed7 MD5 | raw file
   1/*
   2 * CDDL HEADER START
   3 *
   4 * The contents of this file are subject to the terms of the
   5 * Common Development and Distribution License (the "License").
   6 * You may not use this file except in compliance with the License.
   7 *
   8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9 * or http://www.opensolaris.org/os/licensing.
  10 * See the License for the specific language governing permissions
  11 * and limitations under the License.
  12 *
  13 * When distributing Covered Code, include this CDDL HEADER in each
  14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15 * If applicable, add the following below this CDDL HEADER, with the
  16 * fields enclosed by brackets "[]" replaced with your own identifying
  17 * information: Portions Copyright [yyyy] [name of copyright owner]
  18 *
  19 * CDDL HEADER END
  20 */
  21/*
  22 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  23 */
  24
  25/* Portions Copyright 2010 Robert Milkowski */
  26
  27/*
  28 * ZFS volume emulation driver.
  29 *
  30 * Makes a DMU object look like a volume of arbitrary size, up to 2^64 bytes.
  31 * Volumes are accessed through the symbolic links named:
  32 *
  33 * /dev/zvol/dsk/<pool_name>/<dataset_name>
  34 * /dev/zvol/rdsk/<pool_name>/<dataset_name>
  35 *
  36 * These links are created by the /dev filesystem (sdev_zvolops.c).
  37 * Volumes are persistent through reboot.  No user command needs to be
  38 * run before opening and using a device.
  39 */
  40
  41#include <sys/types.h>
  42#include <sys/param.h>
  43#include <sys/errno.h>
  44#include <sys/uio.h>
  45#include <sys/buf.h>
  46#include <sys/modctl.h>
  47#include <sys/open.h>
  48#include <sys/kmem.h>
  49#include <sys/conf.h>
  50#include <sys/cmn_err.h>
  51#include <sys/stat.h>
  52#include <sys/zap.h>
  53#include <sys/spa.h>
  54#include <sys/zio.h>
  55#include <sys/dmu_traverse.h>
  56#include <sys/dnode.h>
  57#include <sys/dsl_dataset.h>
  58#include <sys/dsl_prop.h>
  59#include <sys/dkio.h>
  60#include <sys/efi_partition.h>
  61#include <sys/byteorder.h>
  62#include <sys/pathname.h>
  63#include <sys/ddi.h>
  64#include <sys/sunddi.h>
  65#include <sys/crc32.h>
  66#include <sys/dirent.h>
  67#include <sys/policy.h>
  68#include <sys/fs/zfs.h>
  69#include <sys/zfs_ioctl.h>
  70#include <sys/mkdev.h>
  71#include <sys/zil.h>
  72#include <sys/refcount.h>
  73#include <sys/zfs_znode.h>
  74#include <sys/zfs_rlock.h>
  75#include <sys/vdev_disk.h>
  76#include <sys/vdev_impl.h>
  77#include <sys/zvol.h>
  78#include <sys/dumphdr.h>
  79#include <sys/zil_impl.h>
  80
  81#include "zfs_namecheck.h"
  82
  83void *zfsdev_state;
  84static char *zvol_tag = "zvol_tag";
  85
  86#define	ZVOL_DUMPSIZE		"dumpsize"
  87
  88/*
  89 * This lock protects the zfsdev_state structure from being modified
  90 * while it's being used, e.g. an open that comes in before a create
  91 * finishes.  It also protects temporary opens of the dataset so that,
  92 * e.g., an open doesn't get a spurious EBUSY.
  93 */
  94kmutex_t zfsdev_state_lock;
  95static uint32_t zvol_minors;
  96
  97typedef struct zvol_extent {
  98	list_node_t	ze_node;
  99	dva_t		ze_dva;		/* dva associated with this extent */
 100	uint64_t	ze_nblks;	/* number of blocks in extent */
 101} zvol_extent_t;
 102
 103/*
 104 * The in-core state of each volume.
 105 */
 106typedef struct zvol_state {
 107	char		zv_name[MAXPATHLEN]; /* pool/dd name */
 108	uint64_t	zv_volsize;	/* amount of space we advertise */
 109	uint64_t	zv_volblocksize; /* volume block size */
 110	minor_t		zv_minor;	/* minor number */
 111	uint8_t		zv_min_bs;	/* minimum addressable block shift */
 112	uint8_t		zv_flags;	/* readonly, dumpified, etc. */
 113	objset_t	*zv_objset;	/* objset handle */
 114	uint32_t	zv_open_count[OTYPCNT];	/* open counts */
 115	uint32_t	zv_total_opens;	/* total open count */
 116	zilog_t		*zv_zilog;	/* ZIL handle */
 117	list_t		zv_extents;	/* List of extents for dump */
 118	znode_t		zv_znode;	/* for range locking */
 119	dmu_buf_t	*zv_dbuf;	/* bonus handle */
 120} zvol_state_t;
 121
 122/*
 123 * zvol specific flags
 124 */
 125#define	ZVOL_RDONLY	0x1
 126#define	ZVOL_DUMPIFIED	0x2
 127#define	ZVOL_EXCL	0x4
 128#define	ZVOL_WCE	0x8
 129
 130/*
 131 * zvol maximum transfer in one DMU tx.
 132 */
 133int zvol_maxphys = DMU_MAX_ACCESS/2;
 134
 135extern int zfs_set_prop_nvlist(const char *, zprop_source_t,
 136    nvlist_t *, nvlist_t **);
 137static int zvol_remove_zv(zvol_state_t *);
 138static int zvol_get_data(void *arg, lr_write_t *lr, char *buf, zio_t *zio);
 139static int zvol_dumpify(zvol_state_t *zv);
 140static int zvol_dump_fini(zvol_state_t *zv);
 141static int zvol_dump_init(zvol_state_t *zv, boolean_t resize);
 142
 143static void
 144zvol_size_changed(uint64_t volsize, major_t maj, minor_t min)
 145{
 146	dev_t dev = makedevice(maj, min);
 147
 148	VERIFY(ddi_prop_update_int64(dev, zfs_dip,
 149	    "Size", volsize) == DDI_SUCCESS);
 150	VERIFY(ddi_prop_update_int64(dev, zfs_dip,
 151	    "Nblocks", lbtodb(volsize)) == DDI_SUCCESS);
 152
 153	/* Notify specfs to invalidate the cached size */
 154	spec_size_invalidate(dev, VBLK);
 155	spec_size_invalidate(dev, VCHR);
 156}
 157
 158int
 159zvol_check_volsize(uint64_t volsize, uint64_t blocksize)
 160{
 161	if (volsize == 0)
 162		return (EINVAL);
 163
 164	if (volsize % blocksize != 0)
 165		return (EINVAL);
 166
 167#ifdef _ILP32
 168	if (volsize - 1 > SPEC_MAXOFFSET_T)
 169		return (EOVERFLOW);
 170#endif
 171	return (0);
 172}
 173
 174int
 175zvol_check_volblocksize(uint64_t volblocksize)
 176{
 177	if (volblocksize < SPA_MINBLOCKSIZE ||
 178	    volblocksize > SPA_MAXBLOCKSIZE ||
 179	    !ISP2(volblocksize))
 180		return (EDOM);
 181
 182	return (0);
 183}
 184
 185int
 186zvol_get_stats(objset_t *os, nvlist_t *nv)
 187{
 188	int error;
 189	dmu_object_info_t doi;
 190	uint64_t val;
 191
 192	error = zap_lookup(os, ZVOL_ZAP_OBJ, "size", 8, 1, &val);
 193	if (error)
 194		return (error);
 195
 196	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_VOLSIZE, val);
 197
 198	error = dmu_object_info(os, ZVOL_OBJ, &doi);
 199
 200	if (error == 0) {
 201		dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_VOLBLOCKSIZE,
 202		    doi.doi_data_block_size);
 203	}
 204
 205	return (error);
 206}
 207
 208static zvol_state_t *
 209zvol_minor_lookup(const char *name)
 210{
 211	minor_t minor;
 212	zvol_state_t *zv;
 213
 214	ASSERT(MUTEX_HELD(&zfsdev_state_lock));
 215
 216	for (minor = 1; minor <= ZFSDEV_MAX_MINOR; minor++) {
 217		zv = zfsdev_get_soft_state(minor, ZSST_ZVOL);
 218		if (zv == NULL)
 219			continue;
 220		if (strcmp(zv->zv_name, name) == 0)
 221			return (zv);
 222	}
 223
 224	return (NULL);
 225}
 226
 227/* extent mapping arg */
 228struct maparg {
 229	zvol_state_t	*ma_zv;
 230	uint64_t	ma_blks;
 231};
 232
 233/*ARGSUSED*/
 234static int
 235zvol_map_block(spa_t *spa, zilog_t *zilog, const blkptr_t *bp, arc_buf_t *pbuf,
 236    const zbookmark_t *zb, const dnode_phys_t *dnp, void *arg)
 237{
 238	struct maparg *ma = arg;
 239	zvol_extent_t *ze;
 240	int bs = ma->ma_zv->zv_volblocksize;
 241
 242	if (bp == NULL || zb->zb_object != ZVOL_OBJ || zb->zb_level != 0)
 243		return (0);
 244
 245	VERIFY3U(ma->ma_blks, ==, zb->zb_blkid);
 246	ma->ma_blks++;
 247
 248	/* Abort immediately if we have encountered gang blocks */
 249	if (BP_IS_GANG(bp))
 250		return (EFRAGS);
 251
 252	/*
 253	 * See if the block is at the end of the previous extent.
 254	 */
 255	ze = list_tail(&ma->ma_zv->zv_extents);
 256	if (ze &&
 257	    DVA_GET_VDEV(BP_IDENTITY(bp)) == DVA_GET_VDEV(&ze->ze_dva) &&
 258	    DVA_GET_OFFSET(BP_IDENTITY(bp)) ==
 259	    DVA_GET_OFFSET(&ze->ze_dva) + ze->ze_nblks * bs) {
 260		ze->ze_nblks++;
 261		return (0);
 262	}
 263
 264	dprintf_bp(bp, "%s", "next blkptr:");
 265
 266	/* start a new extent */
 267	ze = kmem_zalloc(sizeof (zvol_extent_t), KM_SLEEP);
 268	ze->ze_dva = bp->blk_dva[0];	/* structure assignment */
 269	ze->ze_nblks = 1;
 270	list_insert_tail(&ma->ma_zv->zv_extents, ze);
 271	return (0);
 272}
 273
 274static void
 275zvol_free_extents(zvol_state_t *zv)
 276{
 277	zvol_extent_t *ze;
 278
 279	while (ze = list_head(&zv->zv_extents)) {
 280		list_remove(&zv->zv_extents, ze);
 281		kmem_free(ze, sizeof (zvol_extent_t));
 282	}
 283}
 284
 285static int
 286zvol_get_lbas(zvol_state_t *zv)
 287{
 288	objset_t *os = zv->zv_objset;
 289	struct maparg	ma;
 290	int		err;
 291
 292	ma.ma_zv = zv;
 293	ma.ma_blks = 0;
 294	zvol_free_extents(zv);
 295
 296	/* commit any in-flight changes before traversing the dataset */
 297	txg_wait_synced(dmu_objset_pool(os), 0);
 298	err = traverse_dataset(dmu_objset_ds(os), 0,
 299	    TRAVERSE_PRE | TRAVERSE_PREFETCH_METADATA, zvol_map_block, &ma);
 300	if (err || ma.ma_blks != (zv->zv_volsize / zv->zv_volblocksize)) {
 301		zvol_free_extents(zv);
 302		return (err ? err : EIO);
 303	}
 304
 305	return (0);
 306}
 307
 308/* ARGSUSED */
 309void
 310zvol_create_cb(objset_t *os, void *arg, cred_t *cr, dmu_tx_t *tx)
 311{
 312	zfs_creat_t *zct = arg;
 313	nvlist_t *nvprops = zct->zct_props;
 314	int error;
 315	uint64_t volblocksize, volsize;
 316
 317	VERIFY(nvlist_lookup_uint64(nvprops,
 318	    zfs_prop_to_name(ZFS_PROP_VOLSIZE), &volsize) == 0);
 319	if (nvlist_lookup_uint64(nvprops,
 320	    zfs_prop_to_name(ZFS_PROP_VOLBLOCKSIZE), &volblocksize) != 0)
 321		volblocksize = zfs_prop_default_numeric(ZFS_PROP_VOLBLOCKSIZE);
 322
 323	/*
 324	 * These properties must be removed from the list so the generic
 325	 * property setting step won't apply to them.
 326	 */
 327	VERIFY(nvlist_remove_all(nvprops,
 328	    zfs_prop_to_name(ZFS_PROP_VOLSIZE)) == 0);
 329	(void) nvlist_remove_all(nvprops,
 330	    zfs_prop_to_name(ZFS_PROP_VOLBLOCKSIZE));
 331
 332	error = dmu_object_claim(os, ZVOL_OBJ, DMU_OT_ZVOL, volblocksize,
 333	    DMU_OT_NONE, 0, tx);
 334	ASSERT(error == 0);
 335
 336	error = zap_create_claim(os, ZVOL_ZAP_OBJ, DMU_OT_ZVOL_PROP,
 337	    DMU_OT_NONE, 0, tx);
 338	ASSERT(error == 0);
 339
 340	error = zap_update(os, ZVOL_ZAP_OBJ, "size", 8, 1, &volsize, tx);
 341	ASSERT(error == 0);
 342}
 343
 344/*
 345 * Replay a TX_WRITE ZIL transaction that didn't get committed
 346 * after a system failure
 347 */
 348static int
 349zvol_replay_write(zvol_state_t *zv, lr_write_t *lr, boolean_t byteswap)
 350{
 351	objset_t *os = zv->zv_objset;
 352	char *data = (char *)(lr + 1);	/* data follows lr_write_t */
 353	uint64_t offset, length;
 354	dmu_tx_t *tx;
 355	int error;
 356
 357	if (byteswap)
 358		byteswap_uint64_array(lr, sizeof (*lr));
 359
 360	offset = lr->lr_offset;
 361	length = lr->lr_length;
 362
 363	/* If it's a dmu_sync() block, write the whole block */
 364	if (lr->lr_common.lrc_reclen == sizeof (lr_write_t)) {
 365		uint64_t blocksize = BP_GET_LSIZE(&lr->lr_blkptr);
 366		if (length < blocksize) {
 367			offset -= offset % blocksize;
 368			length = blocksize;
 369		}
 370	}
 371
 372	tx = dmu_tx_create(os);
 373	dmu_tx_hold_write(tx, ZVOL_OBJ, offset, length);
 374	error = dmu_tx_assign(tx, TXG_WAIT);
 375	if (error) {
 376		dmu_tx_abort(tx);
 377	} else {
 378		dmu_write(os, ZVOL_OBJ, offset, length, data, tx);
 379		dmu_tx_commit(tx);
 380	}
 381
 382	return (error);
 383}
 384
 385/* ARGSUSED */
 386static int
 387zvol_replay_err(zvol_state_t *zv, lr_t *lr, boolean_t byteswap)
 388{
 389	return (ENOTSUP);
 390}
 391
 392/*
 393 * Callback vectors for replaying records.
 394 * Only TX_WRITE is needed for zvol.
 395 */
 396zil_replay_func_t *zvol_replay_vector[TX_MAX_TYPE] = {
 397	zvol_replay_err,	/* 0 no such transaction type */
 398	zvol_replay_err,	/* TX_CREATE */
 399	zvol_replay_err,	/* TX_MKDIR */
 400	zvol_replay_err,	/* TX_MKXATTR */
 401	zvol_replay_err,	/* TX_SYMLINK */
 402	zvol_replay_err,	/* TX_REMOVE */
 403	zvol_replay_err,	/* TX_RMDIR */
 404	zvol_replay_err,	/* TX_LINK */
 405	zvol_replay_err,	/* TX_RENAME */
 406	zvol_replay_write,	/* TX_WRITE */
 407	zvol_replay_err,	/* TX_TRUNCATE */
 408	zvol_replay_err,	/* TX_SETATTR */
 409	zvol_replay_err,	/* TX_ACL */
 410	zvol_replay_err,	/* TX_CREATE_ACL */
 411	zvol_replay_err,	/* TX_CREATE_ATTR */
 412	zvol_replay_err,	/* TX_CREATE_ACL_ATTR */
 413	zvol_replay_err,	/* TX_MKDIR_ACL */
 414	zvol_replay_err,	/* TX_MKDIR_ATTR */
 415	zvol_replay_err,	/* TX_MKDIR_ACL_ATTR */
 416	zvol_replay_err,	/* TX_WRITE2 */
 417};
 418
 419int
 420zvol_name2minor(const char *name, minor_t *minor)
 421{
 422	zvol_state_t *zv;
 423
 424	mutex_enter(&zfsdev_state_lock);
 425	zv = zvol_minor_lookup(name);
 426	if (minor && zv)
 427		*minor = zv->zv_minor;
 428	mutex_exit(&zfsdev_state_lock);
 429	return (zv ? 0 : -1);
 430}
 431
 432/*
 433 * Create a minor node (plus a whole lot more) for the specified volume.
 434 */
 435int
 436zvol_create_minor(const char *name)
 437{
 438	zfs_soft_state_t *zs;
 439	zvol_state_t *zv;
 440	objset_t *os;
 441	dmu_object_info_t doi;
 442	minor_t minor = 0;
 443	char chrbuf[30], blkbuf[30];
 444	int error;
 445
 446	mutex_enter(&zfsdev_state_lock);
 447
 448	if (zvol_minor_lookup(name) != NULL) {
 449		mutex_exit(&zfsdev_state_lock);
 450		return (EEXIST);
 451	}
 452
 453	/* lie and say we're read-only */
 454	error = dmu_objset_own(name, DMU_OST_ZVOL, B_TRUE, FTAG, &os);
 455
 456	if (error) {
 457		mutex_exit(&zfsdev_state_lock);
 458		return (error);
 459	}
 460
 461	if ((minor = zfsdev_minor_alloc()) == 0) {
 462		dmu_objset_disown(os, FTAG);
 463		mutex_exit(&zfsdev_state_lock);
 464		return (ENXIO);
 465	}
 466
 467	if (ddi_soft_state_zalloc(zfsdev_state, minor) != DDI_SUCCESS) {
 468		dmu_objset_disown(os, FTAG);
 469		mutex_exit(&zfsdev_state_lock);
 470		return (EAGAIN);
 471	}
 472	(void) ddi_prop_update_string(minor, zfs_dip, ZVOL_PROP_NAME,
 473	    (char *)name);
 474
 475	(void) snprintf(chrbuf, sizeof (chrbuf), "%u,raw", minor);
 476
 477	if (ddi_create_minor_node(zfs_dip, chrbuf, S_IFCHR,
 478	    minor, DDI_PSEUDO, 0) == DDI_FAILURE) {
 479		ddi_soft_state_free(zfsdev_state, minor);
 480		dmu_objset_disown(os, FTAG);
 481		mutex_exit(&zfsdev_state_lock);
 482		return (EAGAIN);
 483	}
 484
 485	(void) snprintf(blkbuf, sizeof (blkbuf), "%u", minor);
 486
 487	if (ddi_create_minor_node(zfs_dip, blkbuf, S_IFBLK,
 488	    minor, DDI_PSEUDO, 0) == DDI_FAILURE) {
 489		ddi_remove_minor_node(zfs_dip, chrbuf);
 490		ddi_soft_state_free(zfsdev_state, minor);
 491		dmu_objset_disown(os, FTAG);
 492		mutex_exit(&zfsdev_state_lock);
 493		return (EAGAIN);
 494	}
 495
 496	zs = ddi_get_soft_state(zfsdev_state, minor);
 497	zs->zss_type = ZSST_ZVOL;
 498	zv = zs->zss_data = kmem_zalloc(sizeof (zvol_state_t), KM_SLEEP);
 499	(void) strlcpy(zv->zv_name, name, MAXPATHLEN);
 500	zv->zv_min_bs = DEV_BSHIFT;
 501	zv->zv_minor = minor;
 502	zv->zv_objset = os;
 503	if (dmu_objset_is_snapshot(os) || !spa_writeable(dmu_objset_spa(os)))
 504		zv->zv_flags |= ZVOL_RDONLY;
 505	mutex_init(&zv->zv_znode.z_range_lock, NULL, MUTEX_DEFAULT, NULL);
 506	avl_create(&zv->zv_znode.z_range_avl, zfs_range_compare,
 507	    sizeof (rl_t), offsetof(rl_t, r_node));
 508	list_create(&zv->zv_extents, sizeof (zvol_extent_t),
 509	    offsetof(zvol_extent_t, ze_node));
 510	/* get and cache the blocksize */
 511	error = dmu_object_info(os, ZVOL_OBJ, &doi);
 512	ASSERT(error == 0);
 513	zv->zv_volblocksize = doi.doi_data_block_size;
 514
 515	if (spa_writeable(dmu_objset_spa(os))) {
 516		if (zil_replay_disable)
 517			zil_destroy(dmu_objset_zil(os), B_FALSE);
 518		else
 519			zil_replay(os, zv, zvol_replay_vector);
 520	}
 521	dmu_objset_disown(os, FTAG);
 522	zv->zv_objset = NULL;
 523
 524	zvol_minors++;
 525
 526	mutex_exit(&zfsdev_state_lock);
 527
 528	return (0);
 529}
 530
 531/*
 532 * Remove minor node for the specified volume.
 533 */
 534static int
 535zvol_remove_zv(zvol_state_t *zv)
 536{
 537	char nmbuf[20];
 538	minor_t minor = zv->zv_minor;
 539
 540	ASSERT(MUTEX_HELD(&zfsdev_state_lock));
 541	if (zv->zv_total_opens != 0)
 542		return (EBUSY);
 543
 544	(void) snprintf(nmbuf, sizeof (nmbuf), "%u,raw", minor);
 545	ddi_remove_minor_node(zfs_dip, nmbuf);
 546
 547	(void) snprintf(nmbuf, sizeof (nmbuf), "%u", minor);
 548	ddi_remove_minor_node(zfs_dip, nmbuf);
 549
 550	avl_destroy(&zv->zv_znode.z_range_avl);
 551	mutex_destroy(&zv->zv_znode.z_range_lock);
 552
 553	kmem_free(zv, sizeof (zvol_state_t));
 554
 555	ddi_soft_state_free(zfsdev_state, minor);
 556
 557	zvol_minors--;
 558	return (0);
 559}
 560
 561int
 562zvol_remove_minor(const char *name)
 563{
 564	zvol_state_t *zv;
 565	int rc;
 566
 567	mutex_enter(&zfsdev_state_lock);
 568	if ((zv = zvol_minor_lookup(name)) == NULL) {
 569		mutex_exit(&zfsdev_state_lock);
 570		return (ENXIO);
 571	}
 572	rc = zvol_remove_zv(zv);
 573	mutex_exit(&zfsdev_state_lock);
 574	return (rc);
 575}
 576
 577int
 578zvol_first_open(zvol_state_t *zv)
 579{
 580	objset_t *os;
 581	uint64_t volsize;
 582	int error;
 583	uint64_t readonly;
 584
 585	/* lie and say we're read-only */
 586	error = dmu_objset_own(zv->zv_name, DMU_OST_ZVOL, B_TRUE,
 587	    zvol_tag, &os);
 588	if (error)
 589		return (error);
 590
 591	error = zap_lookup(os, ZVOL_ZAP_OBJ, "size", 8, 1, &volsize);
 592	if (error) {
 593		ASSERT(error == 0);
 594		dmu_objset_disown(os, zvol_tag);
 595		return (error);
 596	}
 597	zv->zv_objset = os;
 598	error = dmu_bonus_hold(os, ZVOL_OBJ, zvol_tag, &zv->zv_dbuf);
 599	if (error) {
 600		dmu_objset_disown(os, zvol_tag);
 601		return (error);
 602	}
 603	zv->zv_volsize = volsize;
 604	zv->zv_zilog = zil_open(os, zvol_get_data);
 605	zvol_size_changed(zv->zv_volsize, ddi_driver_major(zfs_dip),
 606	    zv->zv_minor);
 607
 608	VERIFY(dsl_prop_get_integer(zv->zv_name, "readonly", &readonly,
 609	    NULL) == 0);
 610	if (readonly || dmu_objset_is_snapshot(os) ||
 611	    !spa_writeable(dmu_objset_spa(os)))
 612		zv->zv_flags |= ZVOL_RDONLY;
 613	else
 614		zv->zv_flags &= ~ZVOL_RDONLY;
 615	return (error);
 616}
 617
 618void
 619zvol_last_close(zvol_state_t *zv)
 620{
 621	zil_close(zv->zv_zilog);
 622	zv->zv_zilog = NULL;
 623	dmu_buf_rele(zv->zv_dbuf, zvol_tag);
 624	zv->zv_dbuf = NULL;
 625	dmu_objset_disown(zv->zv_objset, zvol_tag);
 626	zv->zv_objset = NULL;
 627}
 628
 629int
 630zvol_prealloc(zvol_state_t *zv)
 631{
 632	objset_t *os = zv->zv_objset;
 633	dmu_tx_t *tx;
 634	uint64_t refd, avail, usedobjs, availobjs;
 635	uint64_t resid = zv->zv_volsize;
 636	uint64_t off = 0;
 637
 638	/* Check the space usage before attempting to allocate the space */
 639	dmu_objset_space(os, &refd, &avail, &usedobjs, &availobjs);
 640	if (avail < zv->zv_volsize)
 641		return (ENOSPC);
 642
 643	/* Free old extents if they exist */
 644	zvol_free_extents(zv);
 645
 646	while (resid != 0) {
 647		int error;
 648		uint64_t bytes = MIN(resid, SPA_MAXBLOCKSIZE);
 649
 650		tx = dmu_tx_create(os);
 651		dmu_tx_hold_write(tx, ZVOL_OBJ, off, bytes);
 652		error = dmu_tx_assign(tx, TXG_WAIT);
 653		if (error) {
 654			dmu_tx_abort(tx);
 655			(void) dmu_free_long_range(os, ZVOL_OBJ, 0, off);
 656			return (error);
 657		}
 658		dmu_prealloc(os, ZVOL_OBJ, off, bytes, tx);
 659		dmu_tx_commit(tx);
 660		off += bytes;
 661		resid -= bytes;
 662	}
 663	txg_wait_synced(dmu_objset_pool(os), 0);
 664
 665	return (0);
 666}
 667
 668int
 669zvol_update_volsize(objset_t *os, uint64_t volsize)
 670{
 671	dmu_tx_t *tx;
 672	int error;
 673
 674	ASSERT(MUTEX_HELD(&zfsdev_state_lock));
 675
 676	tx = dmu_tx_create(os);
 677	dmu_tx_hold_zap(tx, ZVOL_ZAP_OBJ, TRUE, NULL);
 678	error = dmu_tx_assign(tx, TXG_WAIT);
 679	if (error) {
 680		dmu_tx_abort(tx);
 681		return (error);
 682	}
 683
 684	error = zap_update(os, ZVOL_ZAP_OBJ, "size", 8, 1,
 685	    &volsize, tx);
 686	dmu_tx_commit(tx);
 687
 688	if (error == 0)
 689		error = dmu_free_long_range(os,
 690		    ZVOL_OBJ, volsize, DMU_OBJECT_END);
 691	return (error);
 692}
 693
 694void
 695zvol_remove_minors(const char *name)
 696{
 697	zvol_state_t *zv;
 698	char *namebuf;
 699	minor_t minor;
 700
 701	namebuf = kmem_zalloc(strlen(name) + 2, KM_SLEEP);
 702	(void) strncpy(namebuf, name, strlen(name));
 703	(void) strcat(namebuf, "/");
 704	mutex_enter(&zfsdev_state_lock);
 705	for (minor = 1; minor <= ZFSDEV_MAX_MINOR; minor++) {
 706
 707		zv = zfsdev_get_soft_state(minor, ZSST_ZVOL);
 708		if (zv == NULL)
 709			continue;
 710		if (strncmp(namebuf, zv->zv_name, strlen(namebuf)) == 0)
 711			(void) zvol_remove_zv(zv);
 712	}
 713	kmem_free(namebuf, strlen(name) + 2);
 714
 715	mutex_exit(&zfsdev_state_lock);
 716}
 717
 718int
 719zvol_set_volsize(const char *name, major_t maj, uint64_t volsize)
 720{
 721	zvol_state_t *zv = NULL;
 722	objset_t *os;
 723	int error;
 724	dmu_object_info_t doi;
 725	uint64_t old_volsize = 0ULL;
 726	uint64_t readonly;
 727
 728	mutex_enter(&zfsdev_state_lock);
 729	zv = zvol_minor_lookup(name);
 730	if ((error = dmu_objset_hold(name, FTAG, &os)) != 0) {
 731		mutex_exit(&zfsdev_state_lock);
 732		return (error);
 733	}
 734
 735	if ((error = dmu_object_info(os, ZVOL_OBJ, &doi)) != 0 ||
 736	    (error = zvol_check_volsize(volsize,
 737	    doi.doi_data_block_size)) != 0)
 738		goto out;
 739
 740	VERIFY(dsl_prop_get_integer(name, "readonly", &readonly,
 741	    NULL) == 0);
 742	if (readonly) {
 743		error = EROFS;
 744		goto out;
 745	}
 746
 747	error = zvol_update_volsize(os, volsize);
 748	/*
 749	 * Reinitialize the dump area to the new size. If we
 750	 * failed to resize the dump area then restore it back to
 751	 * its original size.
 752	 */
 753	if (zv && error == 0) {
 754		if (zv->zv_flags & ZVOL_DUMPIFIED) {
 755			old_volsize = zv->zv_volsize;
 756			zv->zv_volsize = volsize;
 757			if ((error = zvol_dumpify(zv)) != 0 ||
 758			    (error = dumpvp_resize()) != 0) {
 759				(void) zvol_update_volsize(os, old_volsize);
 760				zv->zv_volsize = old_volsize;
 761				error = zvol_dumpify(zv);
 762			}
 763		}
 764		if (error == 0) {
 765			zv->zv_volsize = volsize;
 766			zvol_size_changed(volsize, maj, zv->zv_minor);
 767		}
 768	}
 769
 770	/*
 771	 * Generate a LUN expansion event.
 772	 */
 773	if (zv && error == 0) {
 774		sysevent_id_t eid;
 775		nvlist_t *attr;
 776		char *physpath = kmem_zalloc(MAXPATHLEN, KM_SLEEP);
 777
 778		(void) snprintf(physpath, MAXPATHLEN, "%s%u", ZVOL_PSEUDO_DEV,
 779		    zv->zv_minor);
 780
 781		VERIFY(nvlist_alloc(&attr, NV_UNIQUE_NAME, KM_SLEEP) == 0);
 782		VERIFY(nvlist_add_string(attr, DEV_PHYS_PATH, physpath) == 0);
 783
 784		(void) ddi_log_sysevent(zfs_dip, SUNW_VENDOR, EC_DEV_STATUS,
 785		    ESC_DEV_DLE, attr, &eid, DDI_SLEEP);
 786
 787		nvlist_free(attr);
 788		kmem_free(physpath, MAXPATHLEN);
 789	}
 790
 791out:
 792	dmu_objset_rele(os, FTAG);
 793
 794	mutex_exit(&zfsdev_state_lock);
 795
 796	return (error);
 797}
 798
 799/*ARGSUSED*/
 800int
 801zvol_open(dev_t *devp, int flag, int otyp, cred_t *cr)
 802{
 803	zvol_state_t *zv;
 804	int err = 0;
 805
 806	mutex_enter(&zfsdev_state_lock);
 807
 808	zv = zfsdev_get_soft_state(getminor(*devp), ZSST_ZVOL);
 809	if (zv == NULL) {
 810		mutex_exit(&zfsdev_state_lock);
 811		return (ENXIO);
 812	}
 813
 814	if (zv->zv_total_opens == 0)
 815		err = zvol_first_open(zv);
 816	if (err) {
 817		mutex_exit(&zfsdev_state_lock);
 818		return (err);
 819	}
 820	if ((flag & FWRITE) && (zv->zv_flags & ZVOL_RDONLY)) {
 821		err = EROFS;
 822		goto out;
 823	}
 824	if (zv->zv_flags & ZVOL_EXCL) {
 825		err = EBUSY;
 826		goto out;
 827	}
 828	if (flag & FEXCL) {
 829		if (zv->zv_total_opens != 0) {
 830			err = EBUSY;
 831			goto out;
 832		}
 833		zv->zv_flags |= ZVOL_EXCL;
 834	}
 835
 836	if (zv->zv_open_count[otyp] == 0 || otyp == OTYP_LYR) {
 837		zv->zv_open_count[otyp]++;
 838		zv->zv_total_opens++;
 839	}
 840	mutex_exit(&zfsdev_state_lock);
 841
 842	return (err);
 843out:
 844	if (zv->zv_total_opens == 0)
 845		zvol_last_close(zv);
 846	mutex_exit(&zfsdev_state_lock);
 847	return (err);
 848}
 849
 850/*ARGSUSED*/
 851int
 852zvol_close(dev_t dev, int flag, int otyp, cred_t *cr)
 853{
 854	minor_t minor = getminor(dev);
 855	zvol_state_t *zv;
 856	int error = 0;
 857
 858	mutex_enter(&zfsdev_state_lock);
 859
 860	zv = zfsdev_get_soft_state(minor, ZSST_ZVOL);
 861	if (zv == NULL) {
 862		mutex_exit(&zfsdev_state_lock);
 863		return (ENXIO);
 864	}
 865
 866	if (zv->zv_flags & ZVOL_EXCL) {
 867		ASSERT(zv->zv_total_opens == 1);
 868		zv->zv_flags &= ~ZVOL_EXCL;
 869	}
 870
 871	/*
 872	 * If the open count is zero, this is a spurious close.
 873	 * That indicates a bug in the kernel / DDI framework.
 874	 */
 875	ASSERT(zv->zv_open_count[otyp] != 0);
 876	ASSERT(zv->zv_total_opens != 0);
 877
 878	/*
 879	 * You may get multiple opens, but only one close.
 880	 */
 881	zv->zv_open_count[otyp]--;
 882	zv->zv_total_opens--;
 883
 884	if (zv->zv_total_opens == 0)
 885		zvol_last_close(zv);
 886
 887	mutex_exit(&zfsdev_state_lock);
 888	return (error);
 889}
 890
 891static void
 892zvol_get_done(zgd_t *zgd, int error)
 893{
 894	if (zgd->zgd_db)
 895		dmu_buf_rele(zgd->zgd_db, zgd);
 896
 897	zfs_range_unlock(zgd->zgd_rl);
 898
 899	if (error == 0 && zgd->zgd_bp)
 900		zil_add_block(zgd->zgd_zilog, zgd->zgd_bp);
 901
 902	kmem_free(zgd, sizeof (zgd_t));
 903}
 904
 905/*
 906 * Get data to generate a TX_WRITE intent log record.
 907 */
 908static int
 909zvol_get_data(void *arg, lr_write_t *lr, char *buf, zio_t *zio)
 910{
 911	zvol_state_t *zv = arg;
 912	objset_t *os = zv->zv_objset;
 913	uint64_t object = ZVOL_OBJ;
 914	uint64_t offset = lr->lr_offset;
 915	uint64_t size = lr->lr_length;	/* length of user data */
 916	blkptr_t *bp = &lr->lr_blkptr;
 917	dmu_buf_t *db;
 918	zgd_t *zgd;
 919	int error;
 920
 921	ASSERT(zio != NULL);
 922	ASSERT(size != 0);
 923
 924	zgd = kmem_zalloc(sizeof (zgd_t), KM_SLEEP);
 925	zgd->zgd_zilog = zv->zv_zilog;
 926	zgd->zgd_rl = zfs_range_lock(&zv->zv_znode, offset, size, RL_READER);
 927
 928	/*
 929	 * Write records come in two flavors: immediate and indirect.
 930	 * For small writes it's cheaper to store the data with the
 931	 * log record (immediate); for large writes it's cheaper to
 932	 * sync the data and get a pointer to it (indirect) so that
 933	 * we don't have to write the data twice.
 934	 */
 935	if (buf != NULL) {	/* immediate write */
 936		error = dmu_read(os, object, offset, size, buf,
 937		    DMU_READ_NO_PREFETCH);
 938	} else {
 939		size = zv->zv_volblocksize;
 940		offset = P2ALIGN(offset, size);
 941		error = dmu_buf_hold(os, object, offset, zgd, &db,
 942		    DMU_READ_NO_PREFETCH);
 943		if (error == 0) {
 944			zgd->zgd_db = db;
 945			zgd->zgd_bp = bp;
 946
 947			ASSERT(db->db_offset == offset);
 948			ASSERT(db->db_size == size);
 949
 950			error = dmu_sync(zio, lr->lr_common.lrc_txg,
 951			    zvol_get_done, zgd);
 952
 953			if (error == 0)
 954				return (0);
 955		}
 956	}
 957
 958	zvol_get_done(zgd, error);
 959
 960	return (error);
 961}
 962
 963/*
 964 * zvol_log_write() handles synchronous writes using TX_WRITE ZIL transactions.
 965 *
 966 * We store data in the log buffers if it's small enough.
 967 * Otherwise we will later flush the data out via dmu_sync().
 968 */
 969ssize_t zvol_immediate_write_sz = 32768;
 970
 971static void
 972zvol_log_write(zvol_state_t *zv, dmu_tx_t *tx, offset_t off, ssize_t resid,
 973    boolean_t sync)
 974{
 975	uint32_t blocksize = zv->zv_volblocksize;
 976	zilog_t *zilog = zv->zv_zilog;
 977	boolean_t slogging;
 978	ssize_t immediate_write_sz;
 979
 980	if (zil_replaying(zilog, tx))
 981		return;
 982
 983	immediate_write_sz = (zilog->zl_logbias == ZFS_LOGBIAS_THROUGHPUT)
 984	    ? 0 : zvol_immediate_write_sz;
 985
 986	slogging = spa_has_slogs(zilog->zl_spa) &&
 987	    (zilog->zl_logbias == ZFS_LOGBIAS_LATENCY);
 988
 989	while (resid) {
 990		itx_t *itx;
 991		lr_write_t *lr;
 992		ssize_t len;
 993		itx_wr_state_t write_state;
 994
 995		/*
 996		 * Unlike zfs_log_write() we can be called with
 997		 * upto DMU_MAX_ACCESS/2 (5MB) writes.
 998		 */
 999		if (blocksize > immediate_write_sz && !slogging &&
1000		    resid >= blocksize && off % blocksize == 0) {
1001			write_state = WR_INDIRECT; /* uses dmu_sync */
1002			len = blocksize;
1003		} else if (sync) {
1004			write_state = WR_COPIED;
1005			len = MIN(ZIL_MAX_LOG_DATA, resid);
1006		} else {
1007			write_state = WR_NEED_COPY;
1008			len = MIN(ZIL_MAX_LOG_DATA, resid);
1009		}
1010
1011		itx = zil_itx_create(TX_WRITE, sizeof (*lr) +
1012		    (write_state == WR_COPIED ? len : 0));
1013		lr = (lr_write_t *)&itx->itx_lr;
1014		if (write_state == WR_COPIED && dmu_read(zv->zv_objset,
1015		    ZVOL_OBJ, off, len, lr + 1, DMU_READ_NO_PREFETCH) != 0) {
1016			zil_itx_destroy(itx);
1017			itx = zil_itx_create(TX_WRITE, sizeof (*lr));
1018			lr = (lr_write_t *)&itx->itx_lr;
1019			write_state = WR_NEED_COPY;
1020		}
1021
1022		itx->itx_wr_state = write_state;
1023		if (write_state == WR_NEED_COPY)
1024			itx->itx_sod += len;
1025		lr->lr_foid = ZVOL_OBJ;
1026		lr->lr_offset = off;
1027		lr->lr_length = len;
1028		lr->lr_blkoff = 0;
1029		BP_ZERO(&lr->lr_blkptr);
1030
1031		itx->itx_private = zv;
1032		itx->itx_sync = sync;
1033
1034		zil_itx_assign(zilog, itx, tx);
1035
1036		off += len;
1037		resid -= len;
1038	}
1039}
1040
1041static int
1042zvol_dumpio_vdev(vdev_t *vd, void *addr, uint64_t offset, uint64_t size,
1043    boolean_t doread, boolean_t isdump)
1044{
1045	vdev_disk_t *dvd;
1046	int c;
1047	int numerrors = 0;
1048
1049	for (c = 0; c < vd->vdev_children; c++) {
1050		ASSERT(vd->vdev_ops == &vdev_mirror_ops ||
1051		    vd->vdev_ops == &vdev_replacing_ops ||
1052		    vd->vdev_ops == &vdev_spare_ops);
1053		int err = zvol_dumpio_vdev(vd->vdev_child[c],
1054		    addr, offset, size, doread, isdump);
1055		if (err != 0) {
1056			numerrors++;
1057		} else if (doread) {
1058			break;
1059		}
1060	}
1061
1062	if (!vd->vdev_ops->vdev_op_leaf)
1063		return (numerrors < vd->vdev_children ? 0 : EIO);
1064
1065	if (doread && !vdev_readable(vd))
1066		return (EIO);
1067	else if (!doread && !vdev_writeable(vd))
1068		return (EIO);
1069
1070	dvd = vd->vdev_tsd;
1071	ASSERT3P(dvd, !=, NULL);
1072	offset += VDEV_LABEL_START_SIZE;
1073
1074	if (ddi_in_panic() || isdump) {
1075		ASSERT(!doread);
1076		if (doread)
1077			return (EIO);
1078		return (ldi_dump(dvd->vd_lh, addr, lbtodb(offset),
1079		    lbtodb(size)));
1080	} else {
1081		return (vdev_disk_physio(dvd->vd_lh, addr, size, offset,
1082		    doread ? B_READ : B_WRITE));
1083	}
1084}
1085
1086static int
1087zvol_dumpio(zvol_state_t *zv, void *addr, uint64_t offset, uint64_t size,
1088    boolean_t doread, boolean_t isdump)
1089{
1090	vdev_t *vd;
1091	int error;
1092	zvol_extent_t *ze;
1093	spa_t *spa = dmu_objset_spa(zv->zv_objset);
1094
1095	/* Must be sector aligned, and not stradle a block boundary. */
1096	if (P2PHASE(offset, DEV_BSIZE) || P2PHASE(size, DEV_BSIZE) ||
1097	    P2BOUNDARY(offset, size, zv->zv_volblocksize)) {
1098		return (EINVAL);
1099	}
1100	ASSERT(size <= zv->zv_volblocksize);
1101
1102	/* Locate the extent this belongs to */
1103	ze = list_head(&zv->zv_extents);
1104	while (offset >= ze->ze_nblks * zv->zv_volblocksize) {
1105		offset -= ze->ze_nblks * zv->zv_volblocksize;
1106		ze = list_next(&zv->zv_extents, ze);
1107	}
1108
1109	if (!ddi_in_panic())
1110		spa_config_enter(spa, SCL_STATE, FTAG, RW_READER);
1111
1112	vd = vdev_lookup_top(spa, DVA_GET_VDEV(&ze->ze_dva));
1113	offset += DVA_GET_OFFSET(&ze->ze_dva);
1114	error = zvol_dumpio_vdev(vd, addr, offset, size, doread, isdump);
1115
1116	if (!ddi_in_panic())
1117		spa_config_exit(spa, SCL_STATE, FTAG);
1118
1119	return (error);
1120}
1121
1122int
1123zvol_strategy(buf_t *bp)
1124{
1125	zfs_soft_state_t *zs = NULL;
1126	zvol_state_t *zv;
1127	uint64_t off, volsize;
1128	size_t resid;
1129	char *addr;
1130	objset_t *os;
1131	rl_t *rl;
1132	int error = 0;
1133	boolean_t doread = bp->b_flags & B_READ;
1134	boolean_t is_dump;
1135	boolean_t sync;
1136
1137	if (getminor(bp->b_edev) == 0) {
1138		error = EINVAL;
1139	} else {
1140		zs = ddi_get_soft_state(zfsdev_state, getminor(bp->b_edev));
1141		if (zs == NULL)
1142			error = ENXIO;
1143		else if (zs->zss_type != ZSST_ZVOL)
1144			error = EINVAL;
1145	}
1146
1147	if (error) {
1148		bioerror(bp, error);
1149		biodone(bp);
1150		return (0);
1151	}
1152
1153	zv = zs->zss_data;
1154
1155	if (!(bp->b_flags & B_READ) && (zv->zv_flags & ZVOL_RDONLY)) {
1156		bioerror(bp, EROFS);
1157		biodone(bp);
1158		return (0);
1159	}
1160
1161	off = ldbtob(bp->b_blkno);
1162	volsize = zv->zv_volsize;
1163
1164	os = zv->zv_objset;
1165	ASSERT(os != NULL);
1166
1167	bp_mapin(bp);
1168	addr = bp->b_un.b_addr;
1169	resid = bp->b_bcount;
1170
1171	if (resid > 0 && (off < 0 || off >= volsize)) {
1172		bioerror(bp, EIO);
1173		biodone(bp);
1174		return (0);
1175	}
1176
1177	is_dump = zv->zv_flags & ZVOL_DUMPIFIED;
1178	sync = ((!(bp->b_flags & B_ASYNC) &&
1179	    !(zv->zv_flags & ZVOL_WCE)) ||
1180	    (zv->zv_objset->os_sync == ZFS_SYNC_ALWAYS)) &&
1181	    !doread && !is_dump;
1182
1183	/*
1184	 * There must be no buffer changes when doing a dmu_sync() because
1185	 * we can't change the data whilst calculating the checksum.
1186	 */
1187	rl = zfs_range_lock(&zv->zv_znode, off, resid,
1188	    doread ? RL_READER : RL_WRITER);
1189
1190	while (resid != 0 && off < volsize) {
1191		size_t size = MIN(resid, zvol_maxphys);
1192		if (is_dump) {
1193			size = MIN(size, P2END(off, zv->zv_volblocksize) - off);
1194			error = zvol_dumpio(zv, addr, off, size,
1195			    doread, B_FALSE);
1196		} else if (doread) {
1197			error = dmu_read(os, ZVOL_OBJ, off, size, addr,
1198			    DMU_READ_PREFETCH);
1199		} else {
1200			dmu_tx_t *tx = dmu_tx_create(os);
1201			dmu_tx_hold_write(tx, ZVOL_OBJ, off, size);
1202			error = dmu_tx_assign(tx, TXG_WAIT);
1203			if (error) {
1204				dmu_tx_abort(tx);
1205			} else {
1206				dmu_write(os, ZVOL_OBJ, off, size, addr, tx);
1207				zvol_log_write(zv, tx, off, size, sync);
1208				dmu_tx_commit(tx);
1209			}
1210		}
1211		if (error) {
1212			/* convert checksum errors into IO errors */
1213			if (error == ECKSUM)
1214				error = EIO;
1215			break;
1216		}
1217		off += size;
1218		addr += size;
1219		resid -= size;
1220	}
1221	zfs_range_unlock(rl);
1222
1223	if ((bp->b_resid = resid) == bp->b_bcount)
1224		bioerror(bp, off > volsize ? EINVAL : error);
1225
1226	if (sync)
1227		zil_commit(zv->zv_zilog, ZVOL_OBJ);
1228	biodone(bp);
1229
1230	return (0);
1231}
1232
1233/*
1234 * Set the buffer count to the zvol maximum transfer.
1235 * Using our own routine instead of the default minphys()
1236 * means that for larger writes we write bigger buffers on X86
1237 * (128K instead of 56K) and flush the disk write cache less often
1238 * (every zvol_maxphys - currently 1MB) instead of minphys (currently
1239 * 56K on X86 and 128K on sparc).
1240 */
1241void
1242zvol_minphys(struct buf *bp)
1243{
1244	if (bp->b_bcount > zvol_maxphys)
1245		bp->b_bcount = zvol_maxphys;
1246}
1247
1248int
1249zvol_dump(dev_t dev, caddr_t addr, daddr_t blkno, int nblocks)
1250{
1251	minor_t minor = getminor(dev);
1252	zvol_state_t *zv;
1253	int error = 0;
1254	uint64_t size;
1255	uint64_t boff;
1256	uint64_t resid;
1257
1258	zv = zfsdev_get_soft_state(minor, ZSST_ZVOL);
1259	if (zv == NULL)
1260		return (ENXIO);
1261
1262	boff = ldbtob(blkno);
1263	resid = ldbtob(nblocks);
1264
1265	VERIFY3U(boff + resid, <=, zv->zv_volsize);
1266
1267	while (resid) {
1268		size = MIN(resid, P2END(boff, zv->zv_volblocksize) - boff);
1269		error = zvol_dumpio(zv, addr, boff, size, B_FALSE, B_TRUE);
1270		if (error)
1271			break;
1272		boff += size;
1273		addr += size;
1274		resid -= size;
1275	}
1276
1277	return (error);
1278}
1279
1280/*ARGSUSED*/
1281int
1282zvol_read(dev_t dev, uio_t *uio, cred_t *cr)
1283{
1284	minor_t minor = getminor(dev);
1285	zvol_state_t *zv;
1286	uint64_t volsize;
1287	rl_t *rl;
1288	int error = 0;
1289
1290	zv = zfsdev_get_soft_state(minor, ZSST_ZVOL);
1291	if (zv == NULL)
1292		return (ENXIO);
1293
1294	volsize = zv->zv_volsize;
1295	if (uio->uio_resid > 0 &&
1296	    (uio->uio_loffset < 0 || uio->uio_loffset >= volsize))
1297		return (EIO);
1298
1299	if (zv->zv_flags & ZVOL_DUMPIFIED) {
1300		error = physio(zvol_strategy, NULL, dev, B_READ,
1301		    zvol_minphys, uio);
1302		return (error);
1303	}
1304
1305	rl = zfs_range_lock(&zv->zv_znode, uio->uio_loffset, uio->uio_resid,
1306	    RL_READER);
1307	while (uio->uio_resid > 0 && uio->uio_loffset < volsize) {
1308		uint64_t bytes = MIN(uio->uio_resid, DMU_MAX_ACCESS >> 1);
1309
1310		/* don't read past the end */
1311		if (bytes > volsize - uio->uio_loffset)
1312			bytes = volsize - uio->uio_loffset;
1313
1314		error =  dmu_read_uio(zv->zv_objset, ZVOL_OBJ, uio, bytes);
1315		if (error) {
1316			/* convert checksum errors into IO errors */
1317			if (error == ECKSUM)
1318				error = EIO;
1319			break;
1320		}
1321	}
1322	zfs_range_unlock(rl);
1323	return (error);
1324}
1325
1326/*ARGSUSED*/
1327int
1328zvol_write(dev_t dev, uio_t *uio, cred_t *cr)
1329{
1330	minor_t minor = getminor(dev);
1331	zvol_state_t *zv;
1332	uint64_t volsize;
1333	rl_t *rl;
1334	int error = 0;
1335	boolean_t sync;
1336
1337	zv = zfsdev_get_soft_state(minor, ZSST_ZVOL);
1338	if (zv == NULL)
1339		return (ENXIO);
1340
1341	volsize = zv->zv_volsize;
1342	if (uio->uio_resid > 0 &&
1343	    (uio->uio_loffset < 0 || uio->uio_loffset >= volsize))
1344		return (EIO);
1345
1346	if (zv->zv_flags & ZVOL_DUMPIFIED) {
1347		error = physio(zvol_strategy, NULL, dev, B_WRITE,
1348		    zvol_minphys, uio);
1349		return (error);
1350	}
1351
1352	sync = !(zv->zv_flags & ZVOL_WCE) ||
1353	    (zv->zv_objset->os_sync == ZFS_SYNC_ALWAYS);
1354
1355	rl = zfs_range_lock(&zv->zv_znode, uio->uio_loffset, uio->uio_resid,
1356	    RL_WRITER);
1357	while (uio->uio_resid > 0 && uio->uio_loffset < volsize) {
1358		uint64_t bytes = MIN(uio->uio_resid, DMU_MAX_ACCESS >> 1);
1359		uint64_t off = uio->uio_loffset;
1360		dmu_tx_t *tx = dmu_tx_create(zv->zv_objset);
1361
1362		if (bytes > volsize - off)	/* don't write past the end */
1363			bytes = volsize - off;
1364
1365		dmu_tx_hold_write(tx, ZVOL_OBJ, off, bytes);
1366		error = dmu_tx_assign(tx, TXG_WAIT);
1367		if (error) {
1368			dmu_tx_abort(tx);
1369			break;
1370		}
1371		error = dmu_write_uio_dbuf(zv->zv_dbuf, uio, bytes, tx);
1372		if (error == 0)
1373			zvol_log_write(zv, tx, off, bytes, sync);
1374		dmu_tx_commit(tx);
1375
1376		if (error)
1377			break;
1378	}
1379	zfs_range_unlock(rl);
1380	if (sync)
1381		zil_commit(zv->zv_zilog, ZVOL_OBJ);
1382	return (error);
1383}
1384
1385int
1386zvol_getefi(void *arg, int flag, uint64_t vs, uint8_t bs)
1387{
1388	struct uuid uuid = EFI_RESERVED;
1389	efi_gpe_t gpe = { 0 };
1390	uint32_t crc;
1391	dk_efi_t efi;
1392	int length;
1393	char *ptr;
1394
1395	if (ddi_copyin(arg, &efi, sizeof (dk_efi_t), flag))
1396		return (EFAULT);
1397	ptr = (char *)(uintptr_t)efi.dki_data_64;
1398	length = efi.dki_length;
1399	/*
1400	 * Some clients may attempt to request a PMBR for the
1401	 * zvol.  Currently this interface will return EINVAL to
1402	 * such requests.  These requests could be supported by
1403	 * adding a check for lba == 0 and consing up an appropriate
1404	 * PMBR.
1405	 */
1406	if (efi.dki_lba < 1 || efi.dki_lba > 2 || length <= 0)
1407		return (EINVAL);
1408
1409	gpe.efi_gpe_StartingLBA = LE_64(34ULL);
1410	gpe.efi_gpe_EndingLBA = LE_64((vs >> bs) - 1);
1411	UUID_LE_CONVERT(gpe.efi_gpe_PartitionTypeGUID, uuid);
1412
1413	if (efi.dki_lba == 1) {
1414		efi_gpt_t gpt = { 0 };
1415
1416		gpt.efi_gpt_Signature = LE_64(EFI_SIGNATURE);
1417		gpt.efi_gpt_Revision = LE_32(EFI_VERSION_CURRENT);
1418		gpt.efi_gpt_HeaderSize = LE_32(sizeof (gpt));
1419		gpt.efi_gpt_MyLBA = LE_64(1ULL);
1420		gpt.efi_gpt_FirstUsableLBA = LE_64(34ULL);
1421		gpt.efi_gpt_LastUsableLBA = LE_64((vs >> bs) - 1);
1422		gpt.efi_gpt_PartitionEntryLBA = LE_64(2ULL);
1423		gpt.efi_gpt_NumberOfPartitionEntries = LE_32(1);
1424		gpt.efi_gpt_SizeOfPartitionEntry =
1425		    LE_32(sizeof (efi_gpe_t));
1426		CRC32(crc, &gpe, sizeof (gpe), -1U, crc32_table);
1427		gpt.efi_gpt_PartitionEntryArrayCRC32 = LE_32(~crc);
1428		CRC32(crc, &gpt, sizeof (gpt), -1U, crc32_table);
1429		gpt.efi_gpt_HeaderCRC32 = LE_32(~crc);
1430		if (ddi_copyout(&gpt, ptr, MIN(sizeof (gpt), length),
1431		    flag))
1432			return (EFAULT);
1433		ptr += sizeof (gpt);
1434		length -= sizeof (gpt);
1435	}
1436	if (length > 0 && ddi_copyout(&gpe, ptr, MIN(sizeof (gpe),
1437	    length), flag))
1438		return (EFAULT);
1439	return (0);
1440}
1441
1442/*
1443 * BEGIN entry points to allow external callers access to the volume.
1444 */
1445/*
1446 * Return the volume parameters needed for access from an external caller.
1447 * These values are invariant as long as the volume is held open.
1448 */
1449int
1450zvol_get_volume_params(minor_t minor, uint64_t *blksize,
1451    uint64_t *max_xfer_len, void **minor_hdl, void **objset_hdl, void **zil_hdl,
1452    void **rl_hdl, void **bonus_hdl)
1453{
1454	zvol_state_t *zv;
1455
1456	zv = zfsdev_get_soft_state(minor, ZSST_ZVOL);
1457	if (zv == NULL)
1458		return (ENXIO);
1459	if (zv->zv_flags & ZVOL_DUMPIFIED)
1460		return (ENXIO);
1461
1462	ASSERT(blksize && max_xfer_len && minor_hdl &&
1463	    objset_hdl && zil_hdl && rl_hdl && bonus_hdl);
1464
1465	*blksize = zv->zv_volblocksize;
1466	*max_xfer_len = (uint64_t)zvol_maxphys;
1467	*minor_hdl = zv;
1468	*objset_hdl = zv->zv_objset;
1469	*zil_hdl = zv->zv_zilog;
1470	*rl_hdl = &zv->zv_znode;
1471	*bonus_hdl = zv->zv_dbuf;
1472	return (0);
1473}
1474
1475/*
1476 * Return the current volume size to an external caller.
1477 * The size can change while the volume is open.
1478 */
1479uint64_t
1480zvol_get_volume_size(void *minor_hdl)
1481{
1482	zvol_state_t *zv = minor_hdl;
1483
1484	return (zv->zv_volsize);
1485}
1486
1487/*
1488 * Return the current WCE setting to an external caller.
1489 * The WCE setting can change while the volume is open.
1490 */
1491int
1492zvol_get_volume_wce(void *minor_hdl)
1493{
1494	zvol_state_t *zv = minor_hdl;
1495
1496	return ((zv->zv_flags & ZVOL_WCE) ? 1 : 0);
1497}
1498
1499/*
1500 * Entry point for external callers to zvol_log_write
1501 */
1502void
1503zvol_log_write_minor(void *minor_hdl, dmu_tx_t *tx, offset_t off, ssize_t resid,
1504    boolean_t sync)
1505{
1506	zvol_state_t *zv = minor_hdl;
1507
1508	zvol_log_write(zv, tx, off, resid, sync);
1509}
1510/*
1511 * END entry points to allow external callers access to the volume.
1512 */
1513
1514/*
1515 * Dirtbag ioctls to support mkfs(1M) for UFS filesystems.  See dkio(7I).
1516 */
1517/*ARGSUSED*/
1518int
1519zvol_ioctl(dev_t dev, int cmd, intptr_t arg, int flag, cred_t *cr, int *rvalp)
1520{
1521	zvol_state_t *zv;
1522	struct dk_cinfo dki;
1523	struct dk_minfo dkm;
1524	struct dk_callback *dkc;
1525	int error = 0;
1526	rl_t *rl;
1527
1528	mutex_enter(&zfsdev_state_lock);
1529
1530	zv = zfsdev_get_soft_state(getminor(dev), ZSST_ZVOL);
1531
1532	if (zv == NULL) {
1533		mutex_exit(&zfsdev_state_lock);
1534		return (ENXIO);
1535	}
1536	ASSERT(zv->zv_total_opens > 0);
1537
1538	switch (cmd) {
1539
1540	case DKIOCINFO:
1541		bzero(&dki, sizeof (dki));
1542		(void) strcpy(dki.dki_cname, "zvol");
1543		(void) strcpy(dki.dki_dname, "zvol");
1544		dki.dki_ctype = DKC_UNKNOWN;
1545		dki.dki_unit = getminor(dev);
1546		dki.dki_maxtransfer = 1 << (SPA_MAXBLOCKSHIFT - zv->zv_min_bs);
1547		mutex_exit(&zfsdev_state_lock);
1548		if (ddi_copyout(&dki, (void *)arg, sizeof (dki), flag))
1549			error = EFAULT;
1550		return (error);
1551
1552	case DKIOCGMEDIAINFO:
1553		bzero(&dkm, sizeof (dkm));
1554		dkm.dki_lbsize = 1U << zv->zv_min_bs;
1555		dkm.dki_capacity = zv->zv_volsize >> zv->zv_min_bs;
1556		dkm.dki_media_type = DK_UNKNOWN;
1557		mutex_exit(&zfsdev_state_lock);
1558		if (ddi_copyout(&dkm, (void *)arg, sizeof (dkm), flag))
1559			error = EFAULT;
1560		return (error);
1561
1562	case DKIOCGETEFI:
1563		{
1564			uint64_t vs = zv->zv_volsize;
1565			uint8_t bs = zv->zv_min_bs;
1566
1567			mutex_exit(&zfsdev_state_lock);
1568			error = zvol_getefi((void *)arg, flag, vs, bs);
1569			return (error);
1570		}
1571
1572	case DKIOCFLUSHWRITECACHE:
1573		dkc = (struct dk_callback *)arg;
1574		mutex_exit(&zfsdev_state_lock);
1575		zil_commit(zv->zv_zilog, ZVOL_OBJ);
1576		if ((flag & FKIOCTL) && dkc != NULL && dkc->dkc_callback) {
1577			(*dkc->dkc_callback)(dkc->dkc_cookie, error);
1578			error = 0;
1579		}
1580		return (error);
1581
1582	case DKIOCGETWCE:
1583		{
1584			int wce = (zv->zv_flags & ZVOL_WCE) ? 1 : 0;
1585			if (ddi_copyout(&wce, (void *)arg, sizeof (int),
1586			    flag))
1587				error = EFAULT;
1588			break;
1589		}
1590	case DKIOCSETWCE:
1591		{
1592			int wce;
1593			if (ddi_copyin((void *)arg, &wce, sizeof (int),
1594			    flag)) {
1595				error = EFAULT;
1596				break;
1597			}
1598			if (wce) {
1599				zv->zv_flags |= ZVOL_WCE;
1600				mutex_exit(&zfsdev_state_lock);
1601			} else {
1602				zv->zv_flags &= ~ZVOL_WCE;
1603				mutex_exit(&zfsdev_state_lock);
1604				zil_commit(zv->zv_zilog, ZVOL_OBJ);
1605			}
1606			return (0);
1607		}
1608
1609	case DKIOCGGEOM:
1610	case DKIOCGVTOC:
1611		/*
1612		 * commands using these (like prtvtoc) expect ENOTSUP
1613		 * since we're emulating an EFI label
1614		 */
1615		error = ENOTSUP;
1616		break;
1617
1618	case DKIOCDUMPINIT:
1619		rl = zfs_range_lock(&zv->zv_znode, 0, zv->zv_volsize,
1620		    RL_WRITER);
1621		error = zvol_dumpify(zv);
1622		zfs_range_unlock(rl);
1623		break;
1624
1625	case DKIOCDUMPFINI:
1626		if (!(zv->zv_flags & ZVOL_DUMPIFIED))
1627			break;
1628		rl = zfs_range_lock(&zv->zv_znode, 0, zv->zv_volsize,
1629		    RL_WRITER);
1630		error = zvol_dump_fini(zv);
1631		zfs_range_unlock(rl);
1632		break;
1633
1634	default:
1635		error = ENOTTY;
1636		break;
1637
1638	}
1639	mutex_exit(&zfsdev_state_lock);
1640	return (error);
1641}
1642
1643int
1644zvol_busy(void)
1645{
1646	return (zvol_minors != 0);
1647}
1648
1649void
1650zvol_init(void)
1651{
1652	VERIFY(ddi_soft_state_init(&zfsdev_state, sizeof (zfs_soft_state_t),
1653	    1) == 0);
1654	mutex_init(&zfsdev_state_lock, NULL, MUTEX_DEFAULT, NULL);
1655}
1656
1657void
1658zvol_fini(void)
1659{
1660	mutex_destroy(&zfsdev_state_lock);
1661	ddi_soft_state_fini(&zfsdev_state);
1662}
1663
1664static int
1665zvol_dump_init(zvol_state_t *zv, boolean_t resize)
1666{
1667	dmu_tx_t *tx;
1668	int error = 0;
1669	objset_t *os = zv->zv_objset;
1670	nvlist_t *nv = NULL;
1671	uint64_t version = spa_version(dmu_objset_spa(zv->zv_objset));
1672
1673	ASSERT(MUTEX_HELD(&zfsdev_state_lock));
1674	error = dmu_free_long_range(zv->zv_objset, ZVOL_OBJ, 0,
1675	    DMU_OBJECT_END);
1676	/* wait for dmu_free_long_range to actually free the blocks */
1677	txg_wait_synced(dmu_objset_pool(zv->zv_objset), 0);
1678
1679	tx = dmu_tx_create(os);
1680	dmu_tx_hold_zap(tx, ZVOL_ZAP_OBJ, TRUE, NULL);
1681	dmu_tx_hold_bonus(tx, ZVOL_OBJ);
1682	error = dmu_tx_assign(tx, TXG_WAIT);
1683	if (error) {
1684		dmu_tx_abort(tx);
1685		return (error);
1686	}
1687
1688	/*
1689	 * If we are resizing the dump device then we only need to
1690	 * update the refreservation to match the newly updated
1691	 * zvolsize. Otherwise, we save off the original state of the
1692	 * zvol so that we can restore them if the zvol is ever undumpified.
1693	 */
1694	if (resize) {
1695		error = zap_update(os, ZVOL_ZAP_OBJ,
1696		    zfs_prop_to_name(ZFS_PROP_REFRESERVATION), 8, 1,
1697		    &zv->zv_volsize, tx);
1698	} else {
1699		uint64_t checksum, compress, refresrv, vbs, dedup;
1700
1701		error = dsl_prop_get_integer(zv->zv_name,
1702		    zfs_prop_to_name(ZFS_PROP_COMPRESSION), &compress, NULL);
1703		error = error ? error : dsl_prop_get_integer(zv->zv_name,
1704		    zfs_prop_to_name(ZFS_PROP_CHECKSUM), &checksum, NULL);
1705		error = error ? error : dsl_prop_get_integer(zv->zv_name,
1706		    zfs_prop_to_name(ZFS_PROP_REFRESERVATION), &refresrv, NULL);
1707		error = error ? error : dsl_prop_get_integer(zv->zv_name,
1708		    zfs_prop_to_name(ZFS_PROP_VOLBLOCKSIZE), &vbs, NULL);
1709		if (version >= SPA_VERSION_DEDUP) {
1710			error = error ? error :
1711			    dsl_prop_get_integer(zv->zv_name,
1712			    zfs_prop_to_name(ZFS_PROP_DEDUP), &dedup, NULL);
1713		}
1714
1715		error = error ? error : zap_update(os, ZVOL_ZAP_OBJ,
1716		    zfs_prop_to_name(ZFS_PROP_COMPRESSION), 8, 1,
1717		    &compress, tx);
1718		error = error ? error : zap_update(os, ZVOL_ZAP_OBJ,
1719		    zfs_prop_to_name(ZFS_PROP_CHECKSUM), 8, 1, &checksum, tx);
1720		error = error ? error : zap_update(os, ZVOL_ZAP_OBJ,
1721		    zfs_prop_to_name(ZFS_PROP_REFRESERVATION), 8, 1,
1722		    &refresrv, tx);
1723		error = error ? error : zap_update(os, ZVOL_ZAP_OBJ,
1724		    zfs_prop_to_name(ZFS_PROP_VOLBLOCKSIZE), 8, 1,
1725		    &vbs, tx);
1726		error = error ? error : dmu_object_set_blocksize(
1727		    os, ZVOL_OBJ, SPA_MAXBLOCKSIZE, 0, tx);
1728		if (version >= SPA_VERSION_DEDUP) {
1729			error = error ? error : zap_update(os, ZVOL_ZAP_OBJ,
1730			    zfs_prop_to_name(ZFS_PROP_DEDUP), 8, 1,
1731			    &dedup, tx);
1732		}
1733		if (error == 0)
1734			zv->zv_volblocksize = SPA_MAXBLOCKSIZE;
1735	}
1736	dmu_tx_commit(tx);
1737
1738	/*
1739	 * We only need update the zvol's property if we are initializing
1740	 * the dump area for the first time.
1741	 */
1742	if (!resize) {
1743		VERIFY(nvlist_alloc(&nv, NV_UNIQUE_NAME, KM_SLEEP) == 0);
1744		VERIFY(nvlist_add_uint64(nv,
1745		    zfs_prop_to_name(ZFS_PROP_REFRESERVATION), 0) == 0);
1746		VERIFY(nvlist_add_uint64(nv,
1747		    zfs_prop_to_name(ZFS_PROP_COMPRESSION),
1748		    ZIO_COMPRESS_OFF) == 0);
1749		VERIFY(nvlist_add_uint64(nv,
1750		    zfs_prop_to_name(ZFS_PROP_CHECKSUM),
1751		    ZIO_CHECKSUM_OFF) == 0);
1752		if (version >= SPA_VERSION_DEDUP) {
1753			VERIFY(nvlist_add_uint64(nv,
1754			    zfs_prop_to_name(ZFS_PROP_DEDUP),
1755			    ZIO_CHECKSUM_OFF) == 0);
1756		}
1757
1758		error = zfs_set_prop_nvlist(zv->zv_name, ZPROP_SRC_LOCAL,
1759		    nv, NULL);
1760		nvlist_free(nv);
1761
1762		if (error)
1763			return (error);
1764	}
1765
1766	/* Allocate the space for the dump */
1767	error = zvol_prealloc(zv);
1768	return (error);
1769}
1770
1771static int
1772zvol_dumpify(zvol_state_t *zv)
1773{
1774	int error = 0;
1775	uint64_t dumpsize = 0;
1776	dmu_tx_t *tx;
1777	objset_t *os = zv->zv_objset;
1778
1779	if (zv->zv_flags & ZVOL_RDONLY)
1780		return (EROFS);
1781
1782	if (zap_lookup(zv->zv_objset, ZVOL_ZAP_OBJ, ZVOL_DUMPSIZE,
1783	    8, 1, &dumpsize) != 0 || dumpsize != zv->zv_volsize) {
1784		boolean_t resize = (dumpsize > 0) ? B_TRUE : B_FALSE;
1785
1786		if ((error = zvol_dump_init(zv, resize)) != 0) {
1787			(void) zvol_dump_fini(zv);
1788			return (error);
1789		}
1790	}
1791
1792	/*
1793	 * Build up our lba mapping.
1794	 */
1795	error = zvol_get_lbas(zv);
1796	if (error) {
1797		(void) zvol_dump_fini(zv);
1798		return (error);
1799	}
1800
1801	tx = dmu_tx_create(os);
1802	dmu_tx_hold_zap(tx, ZVOL_ZAP_OBJ, TRUE, NULL);
1803	error = dmu_tx_assign(tx, TXG_WAIT);
1804	if (error) {
1805		dmu_tx_abort(tx);
1806		(void) zvol_dump_fini(zv);
1807		return (error);
1808	}
1809
1810	zv->zv_flags |= ZVOL_DUMPIFIED;
1811	error = zap_update(os, ZVOL_ZAP_OBJ, ZVOL_DUMPSIZE, 8, 1,
1812	    &zv->zv_volsize, tx);
1813	dmu_tx_commit(tx);
1814
1815	if (error) {
1816		(void) zvol_dump_fini(zv);
1817		return (error);
1818	}
1819
1820	txg_wait_synced(dmu_objset_pool(os), 0);
1821	return (0);
1822}
1823
1824static int
1825zvol_dump_fini(zvol_state_t *zv)
1826{
1827	dmu_tx_t *tx;
1828	objset_t *os = zv->zv_objset;
1829	nvlist_t *nv;
1830	int error = 0;
1831	uint64_t checksum, compress, refresrv, vbs, dedup;
1832	uint64_t version = spa_version(dmu_objset_spa(zv->zv_objset));
1833
1834	/*
1835	 * Attempt to restore the zvol back to its pre-dumpified state.
1836	 * This is a best-effort attempt as it's possible that not all
1837	 * of these properties were initialized during the dumpify process
1838	 * (i.e. error during zvol_dump_init).
1839	 */
1840
1841	tx = dmu_tx_create(os);
1842	dmu_tx_hold_zap(tx, ZVOL_ZAP_OBJ, TRUE, NULL);
1843	error = dmu_tx_assign(tx, TXG_WAIT);
1844	if (error) {
1845		dmu_tx_abort(tx);
1846		return (error);
1847	}
1848	(void) zap_remove(os, ZVOL_ZAP_OBJ, ZVOL_DUMPSIZE, tx);
1849	dmu_tx_commit(tx);
1850
1851	(void) zap_lookup(zv->zv_objset, ZVOL_ZAP_OBJ,
1852	    zfs_prop_to_name(ZFS_PROP_CHECKSUM), 8, 1, &checksum);
1853	(void) zap_lookup(zv->zv_objset, ZVOL_ZAP_OBJ,
1854	    zfs_prop_to_name(ZFS_PROP_COMPRESSION), 8, 1, &compress);
1855	(void) zap_lookup(zv->zv_objset, ZVOL_ZAP_OBJ,
1856	    zfs_prop_to_name(ZFS_PROP_REFRESERVATION), 8, 1, &refresrv);
1857	(void) zap_lookup(zv->zv_objset, ZVOL_ZAP_OBJ,
1858	    zfs_prop_to_name(ZFS_PROP_VOLBLOCKSIZE), 8, 1, &vbs);
1859
1860	VERIFY(nvlist_alloc(&nv, NV_UNIQUE_NAME, KM_SLEEP) == 0);
1861	(void) nvlist_add_uint64(nv,
1862	    zfs_prop_to_name(ZFS_PROP_CHECKSUM), checksum);
1863	(void) nvlist_add_uint64(nv,
1864	    zfs_prop_to_name(ZFS_PROP_COMPRESSION), compress);
1865	(void) nvlist_add_uint64(nv,
1866	    zfs_prop_to_name(ZFS_PROP_REFRESERVATION), refresrv);
1867	if (version >= SPA_VERSION_DEDUP &&
1868	    zap_lookup(zv->zv_objset, ZVOL_ZAP_OBJ,
1869	    zfs_prop_to_name(ZFS_PROP_DEDUP), 8, 1, &dedup) == 0) {
1870		(void) nvlist_add_uint64(nv,
1871		    zfs_prop_to_name(ZFS_PROP_DEDUP), dedup);
1872	}
1873	(void) zfs_set_prop_nvlist(zv->zv_name, ZPROP_SRC_LOCAL,
1874	    nv, NULL);
1875	nvlist_free(nv);
1876
1877	zvol_free_extents(zv);
1878	zv->zv_flags &= ~ZVOL_DUMPIFIED;
1879	(void) dmu_free_long_range(os, ZVOL_OBJ, 0, DMU_OBJECT_END);
1880	/* wait for dmu_free_long_range to actually free the blocks */
1881	txg_wait_synced(dmu_objset_pool(zv->zv_objset), 0);
1882	tx = dmu_tx_create(os);
1883	dmu_tx_hold_bonus(tx, ZVOL_OBJ);
1884	error = dmu_tx_assign(tx, TXG_WAIT);
1885	if (error) {
1886		dmu_tx_abort(tx);
1887		return (error);
1888	}
1889	if (dmu_object_set_blocksize(os, ZVOL_OBJ, vbs, 0, tx) == 0)
1890		zv->zv_volblocksize = vbs;
1891	dmu_tx_commit(tx);
1892
1893	return (0);
1894}