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  * Portions Copyright 2010 Robert Milkowski
  25  *
  26  * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
  27  * Copyright (c) 2012 by Delphix. All rights reserved.
  28  */
  29 
  30 /*
  31  * ZFS volume emulation driver.
  32  *
  33  * Makes a DMU object look like a volume of arbitrary size, up to 2^64 bytes.
  34  * Volumes are accessed through the symbolic links named:
  35  *
  36  * /dev/zvol/dsk/<pool_name>/<dataset_name>
  37  * /dev/zvol/rdsk/<pool_name>/<dataset_name>
  38  *
  39  * These links are created by the /dev filesystem (sdev_zvolops.c).
  40  * Volumes are persistent through reboot.  No user command needs to be
  41  * run before opening and using a device.
  42  */
  43 
  44 #include <sys/types.h>
  45 #include <sys/param.h>
  46 #include <sys/errno.h>
  47 #include <sys/uio.h>
  48 #include <sys/buf.h>
  49 #include <sys/modctl.h>
  50 #include <sys/open.h>
  51 #include <sys/kmem.h>
  52 #include <sys/conf.h>
  53 #include <sys/cmn_err.h>
  54 #include <sys/stat.h>
  55 #include <sys/zap.h>
  56 #include <sys/spa.h>
  57 #include <sys/zio.h>
  58 #include <sys/dmu_traverse.h>
  59 #include <sys/dnode.h>
  60 #include <sys/dsl_dataset.h>
  61 #include <sys/dsl_prop.h>
  62 #include <sys/dkio.h>
  63 #include <sys/efi_partition.h>
  64 #include <sys/byteorder.h>
  65 #include <sys/pathname.h>
  66 #include <sys/ddi.h>
  67 #include <sys/sunddi.h>
  68 #include <sys/crc32.h>
  69 #include <sys/dirent.h>
  70 #include <sys/policy.h>
  71 #include <sys/fs/zfs.h>
  72 #include <sys/zfs_ioctl.h>
  73 #include <sys/mkdev.h>
  74 #include <sys/zil.h>
  75 #include <sys/refcount.h>
  76 #include <sys/zfs_znode.h>
  77 #include <sys/zfs_rlock.h>
  78 #include <sys/vdev_disk.h>
  79 #include <sys/vdev_impl.h>
  80 #include <sys/zvol.h>
  81 #include <sys/dumphdr.h>
  82 #include <sys/zil_impl.h>
  83 
  84 #include "zfs_namecheck.h"
  85 
  86 void *zfsdev_state;
  87 static char *zvol_tag = "zvol_tag";
  88 
  89 #define ZVOL_DUMPSIZE           "dumpsize"
  90 
  91 /*
  92  * This lock protects the zfsdev_state structure from being modified
  93  * while it's being used, e.g. an open that comes in before a create
  94  * finishes.  It also protects temporary opens of the dataset so that,
  95  * e.g., an open doesn't get a spurious EBUSY.
  96  */
  97 kmutex_t zfsdev_state_lock;
  98 static uint32_t zvol_minors;
  99 
 100 typedef struct zvol_extent {
 101         list_node_t     ze_node;
 102         dva_t           ze_dva;         /* dva associated with this extent */
 103         uint64_t        ze_nblks;       /* number of blocks in extent */
 104 } zvol_extent_t;
 105 
 106 /*
 107  * The in-core state of each volume.
 108  */
 109 typedef struct zvol_state {
 110         char            zv_name[MAXPATHLEN]; /* pool/dd name */
 111         uint64_t        zv_volsize;     /* amount of space we advertise */
 112         uint64_t        zv_volblocksize; /* volume block size */
 113         minor_t         zv_minor;       /* minor number */
 114         uint8_t         zv_min_bs;      /* minimum addressable block shift */
 115         uint8_t         zv_flags;       /* readonly, dumpified, etc. */
 116         objset_t        *zv_objset;     /* objset handle */
 117         uint32_t        zv_open_count[OTYPCNT]; /* open counts */
 118         uint32_t        zv_total_opens; /* total open count */
 119         zilog_t         *zv_zilog;      /* ZIL handle */
 120         list_t          zv_extents;     /* List of extents for dump */
 121         znode_t         zv_znode;       /* for range locking */
 122         dmu_buf_t       *zv_dbuf;       /* bonus handle */
 123 } zvol_state_t;
 124 
 125 /*
 126  * zvol specific flags
 127  */
 128 #define ZVOL_RDONLY     0x1
 129 #define ZVOL_DUMPIFIED  0x2
 130 #define ZVOL_EXCL       0x4
 131 #define ZVOL_WCE        0x8
 132 
 133 /*
 134  * zvol maximum transfer in one DMU tx.
 135  */
 136 int zvol_maxphys = DMU_MAX_ACCESS/2;
 137 
 138 extern int zfs_set_prop_nvlist(const char *, zprop_source_t,
 139     nvlist_t *, nvlist_t *);
 140 static int zvol_remove_zv(zvol_state_t *);
 141 static int zvol_get_data(void *arg, lr_write_t *lr, char *buf, zio_t *zio);
 142 static int zvol_dumpify(zvol_state_t *zv);
 143 static int zvol_dump_fini(zvol_state_t *zv);
 144 static int zvol_dump_init(zvol_state_t *zv, boolean_t resize);
 145 
 146 static void
 147 zvol_size_changed(uint64_t volsize, major_t maj, minor_t min)
 148 {
 149         dev_t dev = makedevice(maj, min);
 150 
 151         VERIFY(ddi_prop_update_int64(dev, zfs_dip,
 152             "Size", volsize) == DDI_SUCCESS);
 153         VERIFY(ddi_prop_update_int64(dev, zfs_dip,
 154             "Nblocks", lbtodb(volsize)) == DDI_SUCCESS);
 155 
 156         /* Notify specfs to invalidate the cached size */
 157         spec_size_invalidate(dev, VBLK);
 158         spec_size_invalidate(dev, VCHR);
 159 }
 160 
 161 int
 162 zvol_check_volsize(uint64_t volsize, uint64_t blocksize)
 163 {
 164         if (volsize == 0)
 165                 return (EINVAL);
 166 
 167         if (volsize % blocksize != 0)
 168                 return (EINVAL);
 169 
 170 #ifdef _ILP32
 171         if (volsize - 1 > SPEC_MAXOFFSET_T)
 172                 return (EOVERFLOW);
 173 #endif
 174         return (0);
 175 }
 176 
 177 int
 178 zvol_check_volblocksize(uint64_t volblocksize)
 179 {
 180         if (volblocksize < SPA_MINBLOCKSIZE ||
 181             volblocksize > SPA_MAXBLOCKSIZE ||
 182             !ISP2(volblocksize))
 183                 return (EDOM);
 184 
 185         return (0);
 186 }
 187 
 188 int
 189 zvol_get_stats(objset_t *os, nvlist_t *nv)
 190 {
 191         int error;
 192         dmu_object_info_t doi;
 193         uint64_t val;
 194 
 195         error = zap_lookup(os, ZVOL_ZAP_OBJ, "size", 8, 1, &val);
 196         if (error)
 197                 return (error);
 198 
 199         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_VOLSIZE, val);
 200 
 201         error = dmu_object_info(os, ZVOL_OBJ, &doi);
 202 
 203         if (error == 0) {
 204                 dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_VOLBLOCKSIZE,
 205                     doi.doi_data_block_size);
 206         }
 207 
 208         return (error);
 209 }
 210 
 211 static zvol_state_t *
 212 zvol_minor_lookup(const char *name)
 213 {
 214         minor_t minor;
 215         zvol_state_t *zv;
 216 
 217         ASSERT(MUTEX_HELD(&zfsdev_state_lock));
 218 
 219         for (minor = 1; minor <= ZFSDEV_MAX_MINOR; minor++) {
 220                 zv = zfsdev_get_soft_state(minor, ZSST_ZVOL);
 221                 if (zv == NULL)
 222                         continue;
 223                 if (strcmp(zv->zv_name, name) == 0)
 224                         return (zv);
 225         }
 226 
 227         return (NULL);
 228 }
 229 
 230 /* extent mapping arg */
 231 struct maparg {
 232         zvol_state_t    *ma_zv;
 233         uint64_t        ma_blks;
 234 };
 235 
 236 /*ARGSUSED*/
 237 static int
 238 zvol_map_block(spa_t *spa, zilog_t *zilog, const blkptr_t *bp, arc_buf_t *pbuf,
 239     const zbookmark_t *zb, const dnode_phys_t *dnp, void *arg)
 240 {
 241         struct maparg *ma = arg;
 242         zvol_extent_t *ze;
 243         int bs = ma->ma_zv->zv_volblocksize;
 244 
 245         if (bp == NULL || zb->zb_object != ZVOL_OBJ || zb->zb_level != 0)
 246                 return (0);
 247 
 248         VERIFY3U(ma->ma_blks, ==, zb->zb_blkid);
 249         ma->ma_blks++;
 250 
 251         /* Abort immediately if we have encountered gang blocks */
 252         if (BP_IS_GANG(bp))
 253                 return (EFRAGS);
 254 
 255         /*
 256          * See if the block is at the end of the previous extent.
 257          */
 258         ze = list_tail(&ma->ma_zv->zv_extents);
 259         if (ze &&
 260             DVA_GET_VDEV(BP_IDENTITY(bp)) == DVA_GET_VDEV(&ze->ze_dva) &&
 261             DVA_GET_OFFSET(BP_IDENTITY(bp)) ==
 262             DVA_GET_OFFSET(&ze->ze_dva) + ze->ze_nblks * bs) {
 263                 ze->ze_nblks++;
 264                 return (0);
 265         }
 266 
 267         dprintf_bp(bp, "%s", "next blkptr:");
 268 
 269         /* start a new extent */
 270         ze = kmem_zalloc(sizeof (zvol_extent_t), KM_SLEEP);
 271         ze->ze_dva = bp->blk_dva[0];      /* structure assignment */
 272         ze->ze_nblks = 1;
 273         list_insert_tail(&ma->ma_zv->zv_extents, ze);
 274         return (0);
 275 }
 276 
 277 static void
 278 zvol_free_extents(zvol_state_t *zv)
 279 {
 280         zvol_extent_t *ze;
 281 
 282         while (ze = list_head(&zv->zv_extents)) {
 283                 list_remove(&zv->zv_extents, ze);
 284                 kmem_free(ze, sizeof (zvol_extent_t));
 285         }
 286 }
 287 
 288 static int
 289 zvol_get_lbas(zvol_state_t *zv)
 290 {
 291         objset_t *os = zv->zv_objset;
 292         struct maparg   ma;
 293         int             err;
 294 
 295         ma.ma_zv = zv;
 296         ma.ma_blks = 0;
 297         zvol_free_extents(zv);
 298 
 299         /* commit any in-flight changes before traversing the dataset */
 300         txg_wait_synced(dmu_objset_pool(os), 0);
 301         err = traverse_dataset(dmu_objset_ds(os), 0,
 302             TRAVERSE_PRE | TRAVERSE_PREFETCH_METADATA, zvol_map_block, &ma);
 303         if (err || ma.ma_blks != (zv->zv_volsize / zv->zv_volblocksize)) {
 304                 zvol_free_extents(zv);
 305                 return (err ? err : EIO);
 306         }
 307 
 308         return (0);
 309 }
 310 
 311 /* ARGSUSED */
 312 void
 313 zvol_create_cb(objset_t *os, void *arg, cred_t *cr, dmu_tx_t *tx)
 314 {
 315         zfs_creat_t *zct = arg;
 316         nvlist_t *nvprops = zct->zct_props;
 317         int error;
 318         uint64_t volblocksize, volsize;
 319 
 320         VERIFY(nvlist_lookup_uint64(nvprops,
 321             zfs_prop_to_name(ZFS_PROP_VOLSIZE), &volsize) == 0);
 322         if (nvlist_lookup_uint64(nvprops,
 323             zfs_prop_to_name(ZFS_PROP_VOLBLOCKSIZE), &volblocksize) != 0)
 324                 volblocksize = zfs_prop_default_numeric(ZFS_PROP_VOLBLOCKSIZE);
 325 
 326         /*
 327          * These properties must be removed from the list so the generic
 328          * property setting step won't apply to them.
 329          */
 330         VERIFY(nvlist_remove_all(nvprops,
 331             zfs_prop_to_name(ZFS_PROP_VOLSIZE)) == 0);
 332         (void) nvlist_remove_all(nvprops,
 333             zfs_prop_to_name(ZFS_PROP_VOLBLOCKSIZE));
 334 
 335         error = dmu_object_claim(os, ZVOL_OBJ, DMU_OT_ZVOL, volblocksize,
 336             DMU_OT_NONE, 0, tx);
 337         ASSERT(error == 0);
 338 
 339         error = zap_create_claim(os, ZVOL_ZAP_OBJ, DMU_OT_ZVOL_PROP,
 340             DMU_OT_NONE, 0, tx);
 341         ASSERT(error == 0);
 342 
 343         error = zap_update(os, ZVOL_ZAP_OBJ, "size", 8, 1, &volsize, tx);
 344         ASSERT(error == 0);
 345 }
 346 
 347 /*
 348  * Replay a TX_TRUNCATE ZIL transaction if asked.  TX_TRUNCATE is how we
 349  * implement DKIOCFREE/free-long-range.
 350  */
 351 static int
 352 zvol_replay_truncate(zvol_state_t *zv, lr_truncate_t *lr, boolean_t byteswap)
 353 {
 354         uint64_t offset, length;
 355 
 356         if (byteswap)
 357                 byteswap_uint64_array(lr, sizeof (*lr));
 358 
 359         offset = lr->lr_offset;
 360         length = lr->lr_length;
 361 
 362         return (dmu_free_long_range(zv->zv_objset, ZVOL_OBJ, offset, length));
 363 }
 364 
 365 /*
 366  * Replay a TX_WRITE ZIL transaction that didn't get committed
 367  * after a system failure
 368  */
 369 static int
 370 zvol_replay_write(zvol_state_t *zv, lr_write_t *lr, boolean_t byteswap)
 371 {
 372         objset_t *os = zv->zv_objset;
 373         char *data = (char *)(lr + 1);  /* data follows lr_write_t */
 374         uint64_t offset, length;
 375         dmu_tx_t *tx;
 376         int error;
 377 
 378         if (byteswap)
 379                 byteswap_uint64_array(lr, sizeof (*lr));
 380 
 381         offset = lr->lr_offset;
 382         length = lr->lr_length;
 383 
 384         /* If it's a dmu_sync() block, write the whole block */
 385         if (lr->lr_common.lrc_reclen == sizeof (lr_write_t)) {
 386                 uint64_t blocksize = BP_GET_LSIZE(&lr->lr_blkptr);
 387                 if (length < blocksize) {
 388                         offset -= offset % blocksize;
 389                         length = blocksize;
 390                 }
 391         }
 392 
 393         tx = dmu_tx_create(os);
 394         dmu_tx_hold_write(tx, ZVOL_OBJ, offset, length);
 395         error = dmu_tx_assign(tx, TXG_WAIT);
 396         if (error) {
 397                 dmu_tx_abort(tx);
 398         } else {
 399                 dmu_write(os, ZVOL_OBJ, offset, length, data, tx);
 400                 dmu_tx_commit(tx);
 401         }
 402 
 403         return (error);
 404 }
 405 
 406 /* ARGSUSED */
 407 static int
 408 zvol_replay_err(zvol_state_t *zv, lr_t *lr, boolean_t byteswap)
 409 {
 410         return (ENOTSUP);
 411 }
 412 
 413 /*
 414  * Callback vectors for replaying records.
 415  * Only TX_WRITE and TX_TRUNCATE are needed for zvol.
 416  */
 417 zil_replay_func_t *zvol_replay_vector[TX_MAX_TYPE] = {
 418         zvol_replay_err,        /* 0 no such transaction type */
 419         zvol_replay_err,        /* TX_CREATE */
 420         zvol_replay_err,        /* TX_MKDIR */
 421         zvol_replay_err,        /* TX_MKXATTR */
 422         zvol_replay_err,        /* TX_SYMLINK */
 423         zvol_replay_err,        /* TX_REMOVE */
 424         zvol_replay_err,        /* TX_RMDIR */
 425         zvol_replay_err,        /* TX_LINK */
 426         zvol_replay_err,        /* TX_RENAME */
 427         zvol_replay_write,      /* TX_WRITE */
 428         zvol_replay_truncate,   /* TX_TRUNCATE */
 429         zvol_replay_err,        /* TX_SETATTR */
 430         zvol_replay_err,        /* TX_ACL */
 431         zvol_replay_err,        /* TX_CREATE_ACL */
 432         zvol_replay_err,        /* TX_CREATE_ATTR */
 433         zvol_replay_err,        /* TX_CREATE_ACL_ATTR */
 434         zvol_replay_err,        /* TX_MKDIR_ACL */
 435         zvol_replay_err,        /* TX_MKDIR_ATTR */
 436         zvol_replay_err,        /* TX_MKDIR_ACL_ATTR */
 437         zvol_replay_err,        /* TX_WRITE2 */
 438 };
 439 
 440 int
 441 zvol_name2minor(const char *name, minor_t *minor)
 442 {
 443         zvol_state_t *zv;
 444 
 445         mutex_enter(&zfsdev_state_lock);
 446         zv = zvol_minor_lookup(name);
 447         if (minor && zv)
 448                 *minor = zv->zv_minor;
 449         mutex_exit(&zfsdev_state_lock);
 450         return (zv ? 0 : -1);
 451 }
 452 
 453 /*
 454  * Create a minor node (plus a whole lot more) for the specified volume.
 455  */
 456 int
 457 zvol_create_minor(const char *name)
 458 {
 459         zfs_soft_state_t *zs;
 460         zvol_state_t *zv;
 461         objset_t *os;
 462         dmu_object_info_t doi;
 463         minor_t minor = 0;
 464         char chrbuf[30], blkbuf[30];
 465         int error;
 466 
 467         mutex_enter(&zfsdev_state_lock);
 468 
 469         if (zvol_minor_lookup(name) != NULL) {
 470                 mutex_exit(&zfsdev_state_lock);
 471                 return (EEXIST);
 472         }
 473 
 474         /* lie and say we're read-only */
 475         error = dmu_objset_own(name, DMU_OST_ZVOL, B_TRUE, FTAG, &os);
 476 
 477         if (error) {
 478                 mutex_exit(&zfsdev_state_lock);
 479                 return (error);
 480         }
 481 
 482         if ((minor = zfsdev_minor_alloc()) == 0) {
 483                 dmu_objset_disown(os, FTAG);
 484                 mutex_exit(&zfsdev_state_lock);
 485                 return (ENXIO);
 486         }
 487 
 488         if (ddi_soft_state_zalloc(zfsdev_state, minor) != DDI_SUCCESS) {
 489                 dmu_objset_disown(os, FTAG);
 490                 mutex_exit(&zfsdev_state_lock);
 491                 return (EAGAIN);
 492         }
 493         (void) ddi_prop_update_string(minor, zfs_dip, ZVOL_PROP_NAME,
 494             (char *)name);
 495 
 496         (void) snprintf(chrbuf, sizeof (chrbuf), "%u,raw", minor);
 497 
 498         if (ddi_create_minor_node(zfs_dip, chrbuf, S_IFCHR,
 499             minor, DDI_PSEUDO, 0) == DDI_FAILURE) {
 500                 ddi_soft_state_free(zfsdev_state, minor);
 501                 dmu_objset_disown(os, FTAG);
 502                 mutex_exit(&zfsdev_state_lock);
 503                 return (EAGAIN);
 504         }
 505 
 506         (void) snprintf(blkbuf, sizeof (blkbuf), "%u", minor);
 507 
 508         if (ddi_create_minor_node(zfs_dip, blkbuf, S_IFBLK,
 509             minor, DDI_PSEUDO, 0) == DDI_FAILURE) {
 510                 ddi_remove_minor_node(zfs_dip, chrbuf);
 511                 ddi_soft_state_free(zfsdev_state, minor);
 512                 dmu_objset_disown(os, FTAG);
 513                 mutex_exit(&zfsdev_state_lock);
 514                 return (EAGAIN);
 515         }
 516 
 517         zs = ddi_get_soft_state(zfsdev_state, minor);
 518         zs->zss_type = ZSST_ZVOL;
 519         zv = zs->zss_data = kmem_zalloc(sizeof (zvol_state_t), KM_SLEEP);
 520         (void) strlcpy(zv->zv_name, name, MAXPATHLEN);
 521         zv->zv_min_bs = DEV_BSHIFT;
 522         zv->zv_minor = minor;
 523         zv->zv_objset = os;
 524         if (dmu_objset_is_snapshot(os) || !spa_writeable(dmu_objset_spa(os)))
 525                 zv->zv_flags |= ZVOL_RDONLY;
 526         mutex_init(&zv->zv_znode.z_range_lock, NULL, MUTEX_DEFAULT, NULL);
 527         avl_create(&zv->zv_znode.z_range_avl, zfs_range_compare,
 528             sizeof (rl_t), offsetof(rl_t, r_node));
 529         list_create(&zv->zv_extents, sizeof (zvol_extent_t),
 530             offsetof(zvol_extent_t, ze_node));
 531         /* get and cache the blocksize */
 532         error = dmu_object_info(os, ZVOL_OBJ, &doi);
 533         ASSERT(error == 0);
 534         zv->zv_volblocksize = doi.doi_data_block_size;
 535 
 536         if (spa_writeable(dmu_objset_spa(os))) {
 537                 if (zil_replay_disable)
 538                         zil_destroy(dmu_objset_zil(os), B_FALSE);
 539                 else
 540                         zil_replay(os, zv, zvol_replay_vector);
 541         }
 542         dmu_objset_disown(os, FTAG);
 543         zv->zv_objset = NULL;
 544 
 545         zvol_minors++;
 546 
 547         mutex_exit(&zfsdev_state_lock);
 548 
 549         return (0);
 550 }
 551 
 552 /*
 553  * Remove minor node for the specified volume.
 554  */
 555 static int
 556 zvol_remove_zv(zvol_state_t *zv)
 557 {
 558         char nmbuf[20];
 559         minor_t minor = zv->zv_minor;
 560 
 561         ASSERT(MUTEX_HELD(&zfsdev_state_lock));
 562         if (zv->zv_total_opens != 0)
 563                 return (EBUSY);
 564 
 565         (void) snprintf(nmbuf, sizeof (nmbuf), "%u,raw", minor);
 566         ddi_remove_minor_node(zfs_dip, nmbuf);
 567 
 568         (void) snprintf(nmbuf, sizeof (nmbuf), "%u", minor);
 569         ddi_remove_minor_node(zfs_dip, nmbuf);
 570 
 571         avl_destroy(&zv->zv_znode.z_range_avl);
 572         mutex_destroy(&zv->zv_znode.z_range_lock);
 573 
 574         kmem_free(zv, sizeof (zvol_state_t));
 575 
 576         ddi_soft_state_free(zfsdev_state, minor);
 577 
 578         zvol_minors--;
 579         return (0);
 580 }
 581 
 582 int
 583 zvol_remove_minor(const char *name)
 584 {
 585         zvol_state_t *zv;
 586         int rc;
 587 
 588         mutex_enter(&zfsdev_state_lock);
 589         if ((zv = zvol_minor_lookup(name)) == NULL) {
 590                 mutex_exit(&zfsdev_state_lock);
 591                 return (ENXIO);
 592         }
 593         rc = zvol_remove_zv(zv);
 594         mutex_exit(&zfsdev_state_lock);
 595         return (rc);
 596 }
 597 
 598 int
 599 zvol_first_open(zvol_state_t *zv)
 600 {
 601         objset_t *os;
 602         uint64_t volsize;
 603         int error;
 604         uint64_t readonly;
 605 
 606         /* lie and say we're read-only */
 607         error = dmu_objset_own(zv->zv_name, DMU_OST_ZVOL, B_TRUE,
 608             zvol_tag, &os);
 609         if (error)
 610                 return (error);
 611 
 612         error = zap_lookup(os, ZVOL_ZAP_OBJ, "size", 8, 1, &volsize);
 613         if (error) {
 614                 ASSERT(error == 0);
 615                 dmu_objset_disown(os, zvol_tag);
 616                 return (error);
 617         }
 618         zv->zv_objset = os;
 619         error = dmu_bonus_hold(os, ZVOL_OBJ, zvol_tag, &zv->zv_dbuf);
 620         if (error) {
 621                 dmu_objset_disown(os, zvol_tag);
 622                 return (error);
 623         }
 624         zv->zv_volsize = volsize;
 625         zv->zv_zilog = zil_open(os, zvol_get_data);
 626         zvol_size_changed(zv->zv_volsize, ddi_driver_major(zfs_dip),
 627             zv->zv_minor);
 628 
 629         VERIFY(dsl_prop_get_integer(zv->zv_name, "readonly", &readonly,
 630             NULL) == 0);
 631         if (readonly || dmu_objset_is_snapshot(os) ||
 632             !spa_writeable(dmu_objset_spa(os)))
 633                 zv->zv_flags |= ZVOL_RDONLY;
 634         else
 635                 zv->zv_flags &= ~ZVOL_RDONLY;
 636         return (error);
 637 }
 638 
 639 void
 640 zvol_last_close(zvol_state_t *zv)
 641 {
 642         zil_close(zv->zv_zilog);
 643         zv->zv_zilog = NULL;
 644         dmu_buf_rele(zv->zv_dbuf, zvol_tag);
 645         zv->zv_dbuf = NULL;
 646         dmu_objset_disown(zv->zv_objset, zvol_tag);
 647         zv->zv_objset = NULL;
 648 }
 649 
 650 int
 651 zvol_prealloc(zvol_state_t *zv)
 652 {
 653         objset_t *os = zv->zv_objset;
 654         dmu_tx_t *tx;
 655         uint64_t refd, avail, usedobjs, availobjs;
 656         uint64_t resid = zv->zv_volsize;
 657         uint64_t off = 0;
 658 
 659         /* Check the space usage before attempting to allocate the space */
 660         dmu_objset_space(os, &refd, &avail, &usedobjs, &availobjs);
 661         if (avail < zv->zv_volsize)
 662                 return (ENOSPC);
 663 
 664         /* Free old extents if they exist */
 665         zvol_free_extents(zv);
 666 
 667         while (resid != 0) {
 668                 int error;
 669                 uint64_t bytes = MIN(resid, SPA_MAXBLOCKSIZE);
 670 
 671                 tx = dmu_tx_create(os);
 672                 dmu_tx_hold_write(tx, ZVOL_OBJ, off, bytes);
 673                 error = dmu_tx_assign(tx, TXG_WAIT);
 674                 if (error) {
 675                         dmu_tx_abort(tx);
 676                         (void) dmu_free_long_range(os, ZVOL_OBJ, 0, off);
 677                         return (error);
 678                 }
 679                 dmu_prealloc(os, ZVOL_OBJ, off, bytes, tx);
 680                 dmu_tx_commit(tx);
 681                 off += bytes;
 682                 resid -= bytes;
 683         }
 684         txg_wait_synced(dmu_objset_pool(os), 0);
 685 
 686         return (0);
 687 }
 688 
 689 int
 690 zvol_update_volsize(objset_t *os, uint64_t volsize)
 691 {
 692         dmu_tx_t *tx;
 693         int error;
 694 
 695         ASSERT(MUTEX_HELD(&zfsdev_state_lock));
 696 
 697         tx = dmu_tx_create(os);
 698         dmu_tx_hold_zap(tx, ZVOL_ZAP_OBJ, TRUE, NULL);
 699         error = dmu_tx_assign(tx, TXG_WAIT);
 700         if (error) {
 701                 dmu_tx_abort(tx);
 702                 return (error);
 703         }
 704 
 705         error = zap_update(os, ZVOL_ZAP_OBJ, "size", 8, 1,
 706             &volsize, tx);
 707         dmu_tx_commit(tx);
 708 
 709         if (error == 0)
 710                 error = dmu_free_long_range(os,
 711                     ZVOL_OBJ, volsize, DMU_OBJECT_END);
 712         return (error);
 713 }
 714 
 715 void
 716 zvol_remove_minors(const char *name)
 717 {
 718         zvol_state_t *zv;
 719         char *namebuf;
 720         minor_t minor;
 721 
 722         namebuf = kmem_zalloc(strlen(name) + 2, KM_SLEEP);
 723         (void) strncpy(namebuf, name, strlen(name));
 724         (void) strcat(namebuf, "/");
 725         mutex_enter(&zfsdev_state_lock);
 726         for (minor = 1; minor <= ZFSDEV_MAX_MINOR; minor++) {
 727 
 728                 zv = zfsdev_get_soft_state(minor, ZSST_ZVOL);
 729                 if (zv == NULL)
 730                         continue;
 731                 if (strncmp(namebuf, zv->zv_name, strlen(namebuf)) == 0)
 732                         (void) zvol_remove_zv(zv);
 733         }
 734         kmem_free(namebuf, strlen(name) + 2);
 735 
 736         mutex_exit(&zfsdev_state_lock);
 737 }
 738 
 739 int
 740 zvol_set_volsize(const char *name, major_t maj, uint64_t volsize)
 741 {
 742         zvol_state_t *zv = NULL;
 743         objset_t *os;
 744         int error;
 745         dmu_object_info_t doi;
 746         uint64_t old_volsize = 0ULL;
 747         uint64_t readonly;
 748 
 749         mutex_enter(&zfsdev_state_lock);
 750         zv = zvol_minor_lookup(name);
 751         if ((error = dmu_objset_hold(name, FTAG, &os)) != 0) {
 752                 mutex_exit(&zfsdev_state_lock);
 753                 return (error);
 754         }
 755 
 756         if ((error = dmu_object_info(os, ZVOL_OBJ, &doi)) != 0 ||
 757             (error = zvol_check_volsize(volsize,
 758             doi.doi_data_block_size)) != 0)
 759                 goto out;
 760 
 761         VERIFY(dsl_prop_get_integer(name, "readonly", &readonly,
 762             NULL) == 0);
 763         if (readonly) {
 764                 error = EROFS;
 765                 goto out;
 766         }
 767 
 768         error = zvol_update_volsize(os, volsize);
 769         /*
 770          * Reinitialize the dump area to the new size. If we
 771          * failed to resize the dump area then restore it back to
 772          * its original size.
 773          */
 774         if (zv && error == 0) {
 775                 if (zv->zv_flags & ZVOL_DUMPIFIED) {
 776                         old_volsize = zv->zv_volsize;
 777                         zv->zv_volsize = volsize;
 778                         if ((error = zvol_dumpify(zv)) != 0 ||
 779                             (error = dumpvp_resize()) != 0) {
 780                                 (void) zvol_update_volsize(os, old_volsize);
 781                                 zv->zv_volsize = old_volsize;
 782                                 error = zvol_dumpify(zv);
 783                         }
 784                 }
 785                 if (error == 0) {
 786                         zv->zv_volsize = volsize;
 787                         zvol_size_changed(volsize, maj, zv->zv_minor);
 788                 }
 789         }
 790 
 791         /*
 792          * Generate a LUN expansion event.
 793          */
 794         if (zv && error == 0) {
 795                 sysevent_id_t eid;
 796                 nvlist_t *attr;
 797                 char *physpath = kmem_zalloc(MAXPATHLEN, KM_SLEEP);
 798 
 799                 (void) snprintf(physpath, MAXPATHLEN, "%s%u", ZVOL_PSEUDO_DEV,
 800                     zv->zv_minor);
 801 
 802                 VERIFY(nvlist_alloc(&attr, NV_UNIQUE_NAME, KM_SLEEP) == 0);
 803                 VERIFY(nvlist_add_string(attr, DEV_PHYS_PATH, physpath) == 0);
 804 
 805                 (void) ddi_log_sysevent(zfs_dip, SUNW_VENDOR, EC_DEV_STATUS,
 806                     ESC_DEV_DLE, attr, &eid, DDI_SLEEP);
 807 
 808                 nvlist_free(attr);
 809                 kmem_free(physpath, MAXPATHLEN);
 810         }
 811 
 812 out:
 813         dmu_objset_rele(os, FTAG);
 814 
 815         mutex_exit(&zfsdev_state_lock);
 816 
 817         return (error);
 818 }
 819 
 820 /*ARGSUSED*/
 821 int
 822 zvol_open(dev_t *devp, int flag, int otyp, cred_t *cr)
 823 {
 824         zvol_state_t *zv;
 825         int err = 0;
 826 
 827         mutex_enter(&zfsdev_state_lock);
 828 
 829         zv = zfsdev_get_soft_state(getminor(*devp), ZSST_ZVOL);
 830         if (zv == NULL) {
 831                 mutex_exit(&zfsdev_state_lock);
 832                 return (ENXIO);
 833         }
 834 
 835         if (zv->zv_total_opens == 0)
 836                 err = zvol_first_open(zv);
 837         if (err) {
 838                 mutex_exit(&zfsdev_state_lock);
 839                 return (err);
 840         }
 841         if ((flag & FWRITE) && (zv->zv_flags & ZVOL_RDONLY)) {
 842                 err = EROFS;
 843                 goto out;
 844         }
 845         if (zv->zv_flags & ZVOL_EXCL) {
 846                 err = EBUSY;
 847                 goto out;
 848         }
 849         if (flag & FEXCL) {
 850                 if (zv->zv_total_opens != 0) {
 851                         err = EBUSY;
 852                         goto out;
 853                 }
 854                 zv->zv_flags |= ZVOL_EXCL;
 855         }
 856 
 857         if (zv->zv_open_count[otyp] == 0 || otyp == OTYP_LYR) {
 858                 zv->zv_open_count[otyp]++;
 859                 zv->zv_total_opens++;
 860         }
 861         mutex_exit(&zfsdev_state_lock);
 862 
 863         return (err);
 864 out:
 865         if (zv->zv_total_opens == 0)
 866                 zvol_last_close(zv);
 867         mutex_exit(&zfsdev_state_lock);
 868         return (err);
 869 }
 870 
 871 /*ARGSUSED*/
 872 int
 873 zvol_close(dev_t dev, int flag, int otyp, cred_t *cr)
 874 {
 875         minor_t minor = getminor(dev);
 876         zvol_state_t *zv;
 877         int error = 0;
 878 
 879         mutex_enter(&zfsdev_state_lock);
 880 
 881         zv = zfsdev_get_soft_state(minor, ZSST_ZVOL);
 882         if (zv == NULL) {
 883                 mutex_exit(&zfsdev_state_lock);
 884                 return (ENXIO);
 885         }
 886 
 887         if (zv->zv_flags & ZVOL_EXCL) {
 888                 ASSERT(zv->zv_total_opens == 1);
 889                 zv->zv_flags &= ~ZVOL_EXCL;
 890         }
 891 
 892         /*
 893          * If the open count is zero, this is a spurious close.
 894          * That indicates a bug in the kernel / DDI framework.
 895          */
 896         ASSERT(zv->zv_open_count[otyp] != 0);
 897         ASSERT(zv->zv_total_opens != 0);
 898 
 899         /*
 900          * You may get multiple opens, but only one close.
 901          */
 902         zv->zv_open_count[otyp]--;
 903         zv->zv_total_opens--;
 904 
 905         if (zv->zv_total_opens == 0)
 906                 zvol_last_close(zv);
 907 
 908         mutex_exit(&zfsdev_state_lock);
 909         return (error);
 910 }
 911 
 912 static void
 913 zvol_get_done(zgd_t *zgd, int error)
 914 {
 915         if (zgd->zgd_db)
 916                 dmu_buf_rele(zgd->zgd_db, zgd);
 917 
 918         zfs_range_unlock(zgd->zgd_rl);
 919 
 920         if (error == 0 && zgd->zgd_bp)
 921                 zil_add_block(zgd->zgd_zilog, zgd->zgd_bp);
 922 
 923         kmem_free(zgd, sizeof (zgd_t));
 924 }
 925 
 926 /*
 927  * Get data to generate a TX_WRITE intent log record.
 928  */
 929 static int
 930 zvol_get_data(void *arg, lr_write_t *lr, char *buf, zio_t *zio)
 931 {
 932         zvol_state_t *zv = arg;
 933         objset_t *os = zv->zv_objset;
 934         uint64_t object = ZVOL_OBJ;
 935         uint64_t offset = lr->lr_offset;
 936         uint64_t size = lr->lr_length;       /* length of user data */
 937         blkptr_t *bp = &lr->lr_blkptr;
 938         dmu_buf_t *db;
 939         zgd_t *zgd;
 940         int error;
 941 
 942         ASSERT(zio != NULL);
 943         ASSERT(size != 0);
 944 
 945         zgd = kmem_zalloc(sizeof (zgd_t), KM_SLEEP);
 946         zgd->zgd_zilog = zv->zv_zilog;
 947         zgd->zgd_rl = zfs_range_lock(&zv->zv_znode, offset, size, RL_READER);
 948 
 949         /*
 950          * Write records come in two flavors: immediate and indirect.
 951          * For small writes it's cheaper to store the data with the
 952          * log record (immediate); for large writes it's cheaper to
 953          * sync the data and get a pointer to it (indirect) so that
 954          * we don't have to write the data twice.
 955          */
 956         if (buf != NULL) {      /* immediate write */
 957                 error = dmu_read(os, object, offset, size, buf,
 958                     DMU_READ_NO_PREFETCH);
 959         } else {
 960                 size = zv->zv_volblocksize;
 961                 offset = P2ALIGN(offset, size);
 962                 error = dmu_buf_hold(os, object, offset, zgd, &db,
 963                     DMU_READ_NO_PREFETCH);
 964                 if (error == 0) {
 965                         zgd->zgd_db = db;
 966                         zgd->zgd_bp = bp;
 967 
 968                         ASSERT(db->db_offset == offset);
 969                         ASSERT(db->db_size == size);
 970 
 971                         error = dmu_sync(zio, lr->lr_common.lrc_txg,
 972                             zvol_get_done, zgd);
 973 
 974                         if (error == 0)
 975                                 return (0);
 976                 }
 977         }
 978 
 979         zvol_get_done(zgd, error);
 980 
 981         return (error);
 982 }
 983 
 984 /*
 985  * zvol_log_write() handles synchronous writes using TX_WRITE ZIL transactions.
 986  *
 987  * We store data in the log buffers if it's small enough.
 988  * Otherwise we will later flush the data out via dmu_sync().
 989  */
 990 ssize_t zvol_immediate_write_sz = 32768;
 991 
 992 static void
 993 zvol_log_write(zvol_state_t *zv, dmu_tx_t *tx, offset_t off, ssize_t resid,
 994     boolean_t sync)
 995 {
 996         uint32_t blocksize = zv->zv_volblocksize;
 997         zilog_t *zilog = zv->zv_zilog;
 998         boolean_t slogging;
 999         ssize_t immediate_write_sz;
1000 
1001         if (zil_replaying(zilog, tx))
1002                 return;
1003 
1004         immediate_write_sz = (zilog->zl_logbias == ZFS_LOGBIAS_THROUGHPUT)
1005             ? 0 : zvol_immediate_write_sz;
1006 
1007         slogging = spa_has_slogs(zilog->zl_spa) &&
1008             (zilog->zl_logbias == ZFS_LOGBIAS_LATENCY);
1009 
1010         while (resid) {
1011                 itx_t *itx;
1012                 lr_write_t *lr;
1013                 ssize_t len;
1014                 itx_wr_state_t write_state;
1015 
1016                 /*
1017                  * Unlike zfs_log_write() we can be called with
1018                  * upto DMU_MAX_ACCESS/2 (5MB) writes.
1019                  */
1020                 if (blocksize > immediate_write_sz && !slogging &&
1021                     resid >= blocksize && off % blocksize == 0) {
1022                         write_state = WR_INDIRECT; /* uses dmu_sync */
1023                         len = blocksize;
1024                 } else if (sync) {
1025                         write_state = WR_COPIED;
1026                         len = MIN(ZIL_MAX_LOG_DATA, resid);
1027                 } else {
1028                         write_state = WR_NEED_COPY;
1029                         len = MIN(ZIL_MAX_LOG_DATA, resid);
1030                 }
1031 
1032                 itx = zil_itx_create(TX_WRITE, sizeof (*lr) +
1033                     (write_state == WR_COPIED ? len : 0));
1034                 lr = (lr_write_t *)&itx->itx_lr;
1035                 if (write_state == WR_COPIED && dmu_read(zv->zv_objset,
1036                     ZVOL_OBJ, off, len, lr + 1, DMU_READ_NO_PREFETCH) != 0) {
1037                         zil_itx_destroy(itx);
1038                         itx = zil_itx_create(TX_WRITE, sizeof (*lr));
1039                         lr = (lr_write_t *)&itx->itx_lr;
1040                         write_state = WR_NEED_COPY;
1041                 }
1042 
1043                 itx->itx_wr_state = write_state;
1044                 if (write_state == WR_NEED_COPY)
1045                         itx->itx_sod += len;
1046                 lr->lr_foid = ZVOL_OBJ;
1047                 lr->lr_offset = off;
1048                 lr->lr_length = len;
1049                 lr->lr_blkoff = 0;
1050                 BP_ZERO(&lr->lr_blkptr);
1051 
1052                 itx->itx_private = zv;
1053                 itx->itx_sync = sync;
1054 
1055                 zil_itx_assign(zilog, itx, tx);
1056 
1057                 off += len;
1058                 resid -= len;
1059         }
1060 }
1061 
1062 static int
1063 zvol_dumpio_vdev(vdev_t *vd, void *addr, uint64_t offset, uint64_t size,
1064     boolean_t doread, boolean_t isdump)
1065 {
1066         vdev_disk_t *dvd;
1067         int c;
1068         int numerrors = 0;
1069 
1070         for (c = 0; c < vd->vdev_children; c++) {
1071                 ASSERT(vd->vdev_ops == &vdev_mirror_ops ||
1072                     vd->vdev_ops == &vdev_replacing_ops ||
1073                     vd->vdev_ops == &vdev_spare_ops);
1074                 int err = zvol_dumpio_vdev(vd->vdev_child[c],
1075                     addr, offset, size, doread, isdump);
1076                 if (err != 0) {
1077                         numerrors++;
1078                 } else if (doread) {
1079                         break;
1080                 }
1081         }
1082 
1083         if (!vd->vdev_ops->vdev_op_leaf)
1084                 return (numerrors < vd->vdev_children ? 0 : EIO);
1085 
1086         if (doread && !vdev_readable(vd))
1087                 return (EIO);
1088         else if (!doread && !vdev_writeable(vd))
1089                 return (EIO);
1090 
1091         dvd = vd->vdev_tsd;
1092         ASSERT3P(dvd, !=, NULL);
1093         offset += VDEV_LABEL_START_SIZE;
1094 
1095         if (ddi_in_panic() || isdump) {
1096                 ASSERT(!doread);
1097                 if (doread)
1098                         return (EIO);
1099                 return (ldi_dump(dvd->vd_lh, addr, lbtodb(offset),
1100                     lbtodb(size)));
1101         } else {
1102                 return (vdev_disk_physio(dvd->vd_lh, addr, size, offset,
1103                     doread ? B_READ : B_WRITE));
1104         }
1105 }
1106 
1107 static int
1108 zvol_dumpio(zvol_state_t *zv, void *addr, uint64_t offset, uint64_t size,
1109     boolean_t doread, boolean_t isdump)
1110 {
1111         vdev_t *vd;
1112         int error;
1113         zvol_extent_t *ze;
1114         spa_t *spa = dmu_objset_spa(zv->zv_objset);
1115 
1116         /* Must be sector aligned, and not stradle a block boundary. */
1117         if (P2PHASE(offset, DEV_BSIZE) || P2PHASE(size, DEV_BSIZE) ||
1118             P2BOUNDARY(offset, size, zv->zv_volblocksize)) {
1119                 return (EINVAL);
1120         }
1121         ASSERT(size <= zv->zv_volblocksize);
1122 
1123         /* Locate the extent this belongs to */
1124         ze = list_head(&zv->zv_extents);
1125         while (offset >= ze->ze_nblks * zv->zv_volblocksize) {
1126                 offset -= ze->ze_nblks * zv->zv_volblocksize;
1127                 ze = list_next(&zv->zv_extents, ze);
1128         }
1129 
1130         if (!ddi_in_panic())
1131                 spa_config_enter(spa, SCL_STATE, FTAG, RW_READER);
1132 
1133         vd = vdev_lookup_top(spa, DVA_GET_VDEV(&ze->ze_dva));
1134         offset += DVA_GET_OFFSET(&ze->ze_dva);
1135         error = zvol_dumpio_vdev(vd, addr, offset, size, doread, isdump);
1136 
1137         if (!ddi_in_panic())
1138                 spa_config_exit(spa, SCL_STATE, FTAG);
1139 
1140         return (error);
1141 }
1142 
1143 int
1144 zvol_strategy(buf_t *bp)
1145 {
1146         zfs_soft_state_t *zs = NULL;
1147         zvol_state_t *zv;
1148         uint64_t off, volsize;
1149         size_t resid;
1150         char *addr;
1151         objset_t *os;
1152         rl_t *rl;
1153         int error = 0;
1154         boolean_t doread = bp->b_flags & B_READ;
1155         boolean_t is_dump;
1156         boolean_t sync;
1157 
1158         if (getminor(bp->b_edev) == 0) {
1159                 error = EINVAL;
1160         } else {
1161                 zs = ddi_get_soft_state(zfsdev_state, getminor(bp->b_edev));
1162                 if (zs == NULL)
1163                         error = ENXIO;
1164                 else if (zs->zss_type != ZSST_ZVOL)
1165                         error = EINVAL;
1166         }
1167 
1168         if (error) {
1169                 bioerror(bp, error);
1170                 biodone(bp);
1171                 return (0);
1172         }
1173 
1174         zv = zs->zss_data;
1175 
1176         if (!(bp->b_flags & B_READ) && (zv->zv_flags & ZVOL_RDONLY)) {
1177                 bioerror(bp, EROFS);
1178                 biodone(bp);
1179                 return (0);
1180         }
1181 
1182         off = ldbtob(bp->b_blkno);
1183         volsize = zv->zv_volsize;
1184 
1185         os = zv->zv_objset;
1186         ASSERT(os != NULL);
1187 
1188         bp_mapin(bp);
1189         addr = bp->b_un.b_addr;
1190         resid = bp->b_bcount;
1191 
1192         if (resid > 0 && (off < 0 || off >= volsize)) {
1193                 bioerror(bp, EIO);
1194                 biodone(bp);
1195                 return (0);
1196         }
1197 
1198         is_dump = zv->zv_flags & ZVOL_DUMPIFIED;
1199         sync = ((!(bp->b_flags & B_ASYNC) &&
1200             !(zv->zv_flags & ZVOL_WCE)) ||
1201             (zv->zv_objset->os_sync == ZFS_SYNC_ALWAYS)) &&
1202             !doread && !is_dump;
1203 
1204         /*
1205          * There must be no buffer changes when doing a dmu_sync() because
1206          * we can't change the data whilst calculating the checksum.
1207          */
1208         rl = zfs_range_lock(&zv->zv_znode, off, resid,
1209             doread ? RL_READER : RL_WRITER);
1210 
1211         while (resid != 0 && off < volsize) {
1212                 size_t size = MIN(resid, zvol_maxphys);
1213                 if (is_dump) {
1214                         size = MIN(size, P2END(off, zv->zv_volblocksize) - off);
1215                         error = zvol_dumpio(zv, addr, off, size,
1216                             doread, B_FALSE);
1217                 } else if (doread) {
1218                         error = dmu_read(os, ZVOL_OBJ, off, size, addr,
1219                             DMU_READ_PREFETCH);
1220                 } else {
1221                         dmu_tx_t *tx = dmu_tx_create(os);
1222                         dmu_tx_hold_write(tx, ZVOL_OBJ, off, size);
1223                         error = dmu_tx_assign(tx, TXG_WAIT);
1224                         if (error) {
1225                                 dmu_tx_abort(tx);
1226                         } else {
1227                                 dmu_write(os, ZVOL_OBJ, off, size, addr, tx);
1228                                 zvol_log_write(zv, tx, off, size, sync);
1229                                 dmu_tx_commit(tx);
1230                         }
1231                 }
1232                 if (error) {
1233                         /* convert checksum errors into IO errors */
1234                         if (error == ECKSUM)
1235                                 error = EIO;
1236                         break;
1237                 }
1238                 off += size;
1239                 addr += size;
1240                 resid -= size;
1241         }
1242         zfs_range_unlock(rl);
1243 
1244         if ((bp->b_resid = resid) == bp->b_bcount)
1245                 bioerror(bp, off > volsize ? EINVAL : error);
1246 
1247         if (sync)
1248                 zil_commit(zv->zv_zilog, ZVOL_OBJ);
1249         biodone(bp);
1250 
1251         return (0);
1252 }
1253 
1254 /*
1255  * Set the buffer count to the zvol maximum transfer.
1256  * Using our own routine instead of the default minphys()
1257  * means that for larger writes we write bigger buffers on X86
1258  * (128K instead of 56K) and flush the disk write cache less often
1259  * (every zvol_maxphys - currently 1MB) instead of minphys (currently
1260  * 56K on X86 and 128K on sparc).
1261  */
1262 void
1263 zvol_minphys(struct buf *bp)
1264 {
1265         if (bp->b_bcount > zvol_maxphys)
1266                 bp->b_bcount = zvol_maxphys;
1267 }
1268 
1269 int
1270 zvol_dump(dev_t dev, caddr_t addr, daddr_t blkno, int nblocks)
1271 {
1272         minor_t minor = getminor(dev);
1273         zvol_state_t *zv;
1274         int error = 0;
1275         uint64_t size;
1276         uint64_t boff;
1277         uint64_t resid;
1278 
1279         zv = zfsdev_get_soft_state(minor, ZSST_ZVOL);
1280         if (zv == NULL)
1281                 return (ENXIO);
1282 
1283         boff = ldbtob(blkno);
1284         resid = ldbtob(nblocks);
1285 
1286         VERIFY3U(boff + resid, <=, zv->zv_volsize);
1287 
1288         while (resid) {
1289                 size = MIN(resid, P2END(boff, zv->zv_volblocksize) - boff);
1290                 error = zvol_dumpio(zv, addr, boff, size, B_FALSE, B_TRUE);
1291                 if (error)
1292                         break;
1293                 boff += size;
1294                 addr += size;
1295                 resid -= size;
1296         }
1297 
1298         return (error);
1299 }
1300 
1301 /*ARGSUSED*/
1302 int
1303 zvol_read(dev_t dev, uio_t *uio, cred_t *cr)
1304 {
1305         minor_t minor = getminor(dev);
1306         zvol_state_t *zv;
1307         uint64_t volsize;
1308         rl_t *rl;
1309         int error = 0;
1310 
1311         zv = zfsdev_get_soft_state(minor, ZSST_ZVOL);
1312         if (zv == NULL)
1313                 return (ENXIO);
1314 
1315         volsize = zv->zv_volsize;
1316         if (uio->uio_resid > 0 &&
1317             (uio->uio_loffset < 0 || uio->uio_loffset >= volsize))
1318                 return (EIO);
1319 
1320         if (zv->zv_flags & ZVOL_DUMPIFIED) {
1321                 error = physio(zvol_strategy, NULL, dev, B_READ,
1322                     zvol_minphys, uio);
1323                 return (error);
1324         }
1325 
1326         rl = zfs_range_lock(&zv->zv_znode, uio->uio_loffset, uio->uio_resid,
1327             RL_READER);
1328         while (uio->uio_resid > 0 && uio->uio_loffset < volsize) {
1329                 uint64_t bytes = MIN(uio->uio_resid, DMU_MAX_ACCESS >> 1);
1330 
1331                 /* don't read past the end */
1332                 if (bytes > volsize - uio->uio_loffset)
1333                         bytes = volsize - uio->uio_loffset;
1334 
1335                 error =  dmu_read_uio(zv->zv_objset, ZVOL_OBJ, uio, bytes);
1336                 if (error) {
1337                         /* convert checksum errors into IO errors */
1338                         if (error == ECKSUM)
1339                                 error = EIO;
1340                         break;
1341                 }
1342         }
1343         zfs_range_unlock(rl);
1344         return (error);
1345 }
1346 
1347 /*ARGSUSED*/
1348 int
1349 zvol_write(dev_t dev, uio_t *uio, cred_t *cr)
1350 {
1351         minor_t minor = getminor(dev);
1352         zvol_state_t *zv;
1353         uint64_t volsize;
1354         rl_t *rl;
1355         int error = 0;
1356         boolean_t sync;
1357 
1358         zv = zfsdev_get_soft_state(minor, ZSST_ZVOL);
1359         if (zv == NULL)
1360                 return (ENXIO);
1361 
1362         volsize = zv->zv_volsize;
1363         if (uio->uio_resid > 0 &&
1364             (uio->uio_loffset < 0 || uio->uio_loffset >= volsize))
1365                 return (EIO);
1366 
1367         if (zv->zv_flags & ZVOL_DUMPIFIED) {
1368                 error = physio(zvol_strategy, NULL, dev, B_WRITE,
1369                     zvol_minphys, uio);
1370                 return (error);
1371         }
1372 
1373         sync = !(zv->zv_flags & ZVOL_WCE) ||
1374             (zv->zv_objset->os_sync == ZFS_SYNC_ALWAYS);
1375 
1376         rl = zfs_range_lock(&zv->zv_znode, uio->uio_loffset, uio->uio_resid,
1377             RL_WRITER);
1378         while (uio->uio_resid > 0 && uio->uio_loffset < volsize) {
1379                 uint64_t bytes = MIN(uio->uio_resid, DMU_MAX_ACCESS >> 1);
1380                 uint64_t off = uio->uio_loffset;
1381                 dmu_tx_t *tx = dmu_tx_create(zv->zv_objset);
1382 
1383                 if (bytes > volsize - off)   /* don't write past the end */
1384                         bytes = volsize - off;
1385 
1386                 dmu_tx_hold_write(tx, ZVOL_OBJ, off, bytes);
1387                 error = dmu_tx_assign(tx, TXG_WAIT);
1388                 if (error) {
1389                         dmu_tx_abort(tx);
1390                         break;
1391                 }
1392                 error = dmu_write_uio_dbuf(zv->zv_dbuf, uio, bytes, tx);
1393                 if (error == 0)
1394                         zvol_log_write(zv, tx, off, bytes, sync);
1395                 dmu_tx_commit(tx);
1396 
1397                 if (error)
1398                         break;
1399         }
1400         zfs_range_unlock(rl);
1401         if (sync)
1402                 zil_commit(zv->zv_zilog, ZVOL_OBJ);
1403         return (error);
1404 }
1405 
1406 int
1407 zvol_getefi(void *arg, int flag, uint64_t vs, uint8_t bs)
1408 {
1409         struct uuid uuid = EFI_RESERVED;
1410         efi_gpe_t gpe = { 0 };
1411         uint32_t crc;
1412         dk_efi_t efi;
1413         int length;
1414         char *ptr;
1415 
1416         if (ddi_copyin(arg, &efi, sizeof (dk_efi_t), flag))
1417                 return (EFAULT);
1418         ptr = (char *)(uintptr_t)efi.dki_data_64;
1419         length = efi.dki_length;
1420         /*
1421          * Some clients may attempt to request a PMBR for the
1422          * zvol.  Currently this interface will return EINVAL to
1423          * such requests.  These requests could be supported by
1424          * adding a check for lba == 0 and consing up an appropriate
1425          * PMBR.
1426          */
1427         if (efi.dki_lba < 1 || efi.dki_lba > 2 || length <= 0)
1428                 return (EINVAL);
1429 
1430         gpe.efi_gpe_StartingLBA = LE_64(34ULL);
1431         gpe.efi_gpe_EndingLBA = LE_64((vs >> bs) - 1);
1432         UUID_LE_CONVERT(gpe.efi_gpe_PartitionTypeGUID, uuid);
1433 
1434         if (efi.dki_lba == 1) {
1435                 efi_gpt_t gpt = { 0 };
1436 
1437                 gpt.efi_gpt_Signature = LE_64(EFI_SIGNATURE);
1438                 gpt.efi_gpt_Revision = LE_32(EFI_VERSION_CURRENT);
1439                 gpt.efi_gpt_HeaderSize = LE_32(sizeof (gpt));
1440                 gpt.efi_gpt_MyLBA = LE_64(1ULL);
1441                 gpt.efi_gpt_FirstUsableLBA = LE_64(34ULL);
1442                 gpt.efi_gpt_LastUsableLBA = LE_64((vs >> bs) - 1);
1443                 gpt.efi_gpt_PartitionEntryLBA = LE_64(2ULL);
1444                 gpt.efi_gpt_NumberOfPartitionEntries = LE_32(1);
1445                 gpt.efi_gpt_SizeOfPartitionEntry =
1446                     LE_32(sizeof (efi_gpe_t));
1447                 CRC32(crc, &gpe, sizeof (gpe), -1U, crc32_table);
1448                 gpt.efi_gpt_PartitionEntryArrayCRC32 = LE_32(~crc);
1449                 CRC32(crc, &gpt, sizeof (gpt), -1U, crc32_table);
1450                 gpt.efi_gpt_HeaderCRC32 = LE_32(~crc);
1451                 if (ddi_copyout(&gpt, ptr, MIN(sizeof (gpt), length),
1452                     flag))
1453                         return (EFAULT);
1454                 ptr += sizeof (gpt);
1455                 length -= sizeof (gpt);
1456         }
1457         if (length > 0 && ddi_copyout(&gpe, ptr, MIN(sizeof (gpe),
1458             length), flag))
1459                 return (EFAULT);
1460         return (0);
1461 }
1462 
1463 /*
1464  * BEGIN entry points to allow external callers access to the volume.
1465  */
1466 /*
1467  * Return the volume parameters needed for access from an external caller.
1468  * These values are invariant as long as the volume is held open.
1469  */
1470 int
1471 zvol_get_volume_params(minor_t minor, uint64_t *blksize,
1472     uint64_t *max_xfer_len, void **minor_hdl, void **objset_hdl, void **zil_hdl,
1473     void **rl_hdl, void **bonus_hdl)
1474 {
1475         zvol_state_t *zv;
1476 
1477         zv = zfsdev_get_soft_state(minor, ZSST_ZVOL);
1478         if (zv == NULL)
1479                 return (ENXIO);
1480         if (zv->zv_flags & ZVOL_DUMPIFIED)
1481                 return (ENXIO);
1482 
1483         ASSERT(blksize && max_xfer_len && minor_hdl &&
1484             objset_hdl && zil_hdl && rl_hdl && bonus_hdl);
1485 
1486         *blksize = zv->zv_volblocksize;
1487         *max_xfer_len = (uint64_t)zvol_maxphys;
1488         *minor_hdl = zv;
1489         *objset_hdl = zv->zv_objset;
1490         *zil_hdl = zv->zv_zilog;
1491         *rl_hdl = &zv->zv_znode;
1492         *bonus_hdl = zv->zv_dbuf;
1493         return (0);
1494 }
1495 
1496 /*
1497  * Return the current volume size to an external caller.
1498  * The size can change while the volume is open.
1499  */
1500 uint64_t
1501 zvol_get_volume_size(void *minor_hdl)
1502 {
1503         zvol_state_t *zv = minor_hdl;
1504 
1505         return (zv->zv_volsize);
1506 }
1507 
1508 /*
1509  * Return the current WCE setting to an external caller.
1510  * The WCE setting can change while the volume is open.
1511  */
1512 int
1513 zvol_get_volume_wce(void *minor_hdl)
1514 {
1515         zvol_state_t *zv = minor_hdl;
1516 
1517         return ((zv->zv_flags & ZVOL_WCE) ? 1 : 0);
1518 }
1519 
1520 /*
1521  * Entry point for external callers to zvol_log_write
1522  */
1523 void
1524 zvol_log_write_minor(void *minor_hdl, dmu_tx_t *tx, offset_t off, ssize_t resid,
1525     boolean_t sync)
1526 {
1527         zvol_state_t *zv = minor_hdl;
1528 
1529         zvol_log_write(zv, tx, off, resid, sync);
1530 }
1531 /*
1532  * END entry points to allow external callers access to the volume.
1533  */
1534 
1535 /*
1536  * Log a DKIOCFREE/free-long-range to the ZIL with TX_TRUNCATE.
1537  */
1538 static void
1539 zvol_log_truncate(zvol_state_t *zv, dmu_tx_t *tx, uint64_t off, uint64_t len,
1540     boolean_t sync)
1541 {
1542         itx_t *itx;
1543         lr_truncate_t *lr;
1544         zilog_t *zilog = zv->zv_zilog;
1545 
1546         if (zil_replaying(zilog, tx))
1547                 return;
1548 
1549         itx = zil_itx_create(TX_TRUNCATE, sizeof (*lr));
1550         lr = (lr_truncate_t *)&itx->itx_lr;
1551         lr->lr_foid = ZVOL_OBJ;
1552         lr->lr_offset = off;
1553         lr->lr_length = len;
1554 
1555         itx->itx_sync = sync;
1556         zil_itx_assign(zilog, itx, tx);
1557 }
1558 
1559 /*
1560  * Dirtbag ioctls to support mkfs(1M) for UFS filesystems.  See dkio(7I).
1561  * Also a dirtbag dkio ioctl for unmap/free-block functionality.
1562  */
1563 /*ARGSUSED*/
1564 int
1565 zvol_ioctl(dev_t dev, int cmd, intptr_t arg, int flag, cred_t *cr, int *rvalp)
1566 {
1567         zvol_state_t *zv;
1568         struct dk_cinfo dki;
1569         struct dk_minfo dkm;
1570         struct dk_callback *dkc;
1571         int error = 0;
1572         rl_t *rl;
1573 
1574         mutex_enter(&zfsdev_state_lock);
1575 
1576         zv = zfsdev_get_soft_state(getminor(dev), ZSST_ZVOL);
1577 
1578         if (zv == NULL) {
1579                 mutex_exit(&zfsdev_state_lock);
1580                 return (ENXIO);
1581         }
1582         ASSERT(zv->zv_total_opens > 0);
1583 
1584         switch (cmd) {
1585 
1586         case DKIOCINFO:
1587                 bzero(&dki, sizeof (dki));
1588                 (void) strcpy(dki.dki_cname, "zvol");
1589                 (void) strcpy(dki.dki_dname, "zvol");
1590                 dki.dki_ctype = DKC_UNKNOWN;
1591                 dki.dki_unit = getminor(dev);
1592                 dki.dki_maxtransfer = 1 << (SPA_MAXBLOCKSHIFT - zv->zv_min_bs);
1593                 mutex_exit(&zfsdev_state_lock);
1594                 if (ddi_copyout(&dki, (void *)arg, sizeof (dki), flag))
1595                         error = EFAULT;
1596                 return (error);
1597 
1598         case DKIOCGMEDIAINFO:
1599                 bzero(&dkm, sizeof (dkm));
1600                 dkm.dki_lbsize = 1U << zv->zv_min_bs;
1601                 dkm.dki_capacity = zv->zv_volsize >> zv->zv_min_bs;
1602                 dkm.dki_media_type = DK_UNKNOWN;
1603                 mutex_exit(&zfsdev_state_lock);
1604                 if (ddi_copyout(&dkm, (void *)arg, sizeof (dkm), flag))
1605                         error = EFAULT;
1606                 return (error);
1607 
1608         case DKIOCGETEFI:
1609                 {
1610                         uint64_t vs = zv->zv_volsize;
1611                         uint8_t bs = zv->zv_min_bs;
1612 
1613                         mutex_exit(&zfsdev_state_lock);
1614                         error = zvol_getefi((void *)arg, flag, vs, bs);
1615                         return (error);
1616                 }
1617 
1618         case DKIOCFLUSHWRITECACHE:
1619                 dkc = (struct dk_callback *)arg;
1620                 mutex_exit(&zfsdev_state_lock);
1621                 zil_commit(zv->zv_zilog, ZVOL_OBJ);
1622                 if ((flag & FKIOCTL) && dkc != NULL && dkc->dkc_callback) {
1623                         (*dkc->dkc_callback)(dkc->dkc_cookie, error);
1624                         error = 0;
1625                 }
1626                 return (error);
1627 
1628         case DKIOCGETWCE:
1629                 {
1630                         int wce = (zv->zv_flags & ZVOL_WCE) ? 1 : 0;
1631                         if (ddi_copyout(&wce, (void *)arg, sizeof (int),
1632                             flag))
1633                                 error = EFAULT;
1634                         break;
1635                 }
1636         case DKIOCSETWCE:
1637                 {
1638                         int wce;
1639                         if (ddi_copyin((void *)arg, &wce, sizeof (int),
1640                             flag)) {
1641                                 error = EFAULT;
1642                                 break;
1643                         }
1644                         if (wce) {
1645                                 zv->zv_flags |= ZVOL_WCE;
1646                                 mutex_exit(&zfsdev_state_lock);
1647                         } else {
1648                                 zv->zv_flags &= ~ZVOL_WCE;
1649                                 mutex_exit(&zfsdev_state_lock);
1650                                 zil_commit(zv->zv_zilog, ZVOL_OBJ);
1651                         }
1652                         return (0);
1653                 }
1654 
1655         case DKIOCGGEOM:
1656         case DKIOCGVTOC:
1657                 /*
1658                  * commands using these (like prtvtoc) expect ENOTSUP
1659                  * since we're emulating an EFI label
1660                  */
1661                 error = ENOTSUP;
1662                 break;
1663 
1664         case DKIOCDUMPINIT:
1665                 rl = zfs_range_lock(&zv->zv_znode, 0, zv->zv_volsize,
1666                     RL_WRITER);
1667                 error = zvol_dumpify(zv);
1668                 zfs_range_unlock(rl);
1669                 break;
1670 
1671         case DKIOCDUMPFINI:
1672                 if (!(zv->zv_flags & ZVOL_DUMPIFIED))
1673                         break;
1674                 rl = zfs_range_lock(&zv->zv_znode, 0, zv->zv_volsize,
1675                     RL_WRITER);
1676                 error = zvol_dump_fini(zv);
1677                 zfs_range_unlock(rl);
1678                 break;
1679 
1680         case DKIOCFREE:
1681         {
1682                 dkioc_free_t df;
1683                 dmu_tx_t *tx;
1684 
1685                 if (ddi_copyin((void *)arg, &df, sizeof (df), flag)) {
1686                         error = EFAULT;
1687                         break;
1688                 }
1689 
1690                 /*
1691                  * Apply Postel's Law to length-checking.  If they overshoot,
1692                  * just blank out until the end, if there's a need to blank
1693                  * out anything.
1694                  */
1695                 if (df.df_start >= zv->zv_volsize)
1696                         break;  /* No need to do anything... */
1697                 if (df.df_start + df.df_length > zv->zv_volsize)
1698                         df.df_length = DMU_OBJECT_END;
1699 
1700                 rl = zfs_range_lock(&zv->zv_znode, df.df_start, df.df_length,
1701                     RL_WRITER);
1702                 tx = dmu_tx_create(zv->zv_objset);
1703                 error = dmu_tx_assign(tx, TXG_WAIT);
1704                 if (error != 0) {
1705                         dmu_tx_abort(tx);
1706                 } else {
1707                         zvol_log_truncate(zv, tx, df.df_start,
1708                             df.df_length, B_TRUE);
1709                         dmu_tx_commit(tx);
1710                         error = dmu_free_long_range(zv->zv_objset, ZVOL_OBJ,
1711                             df.df_start, df.df_length);
1712                 }
1713 
1714                 zfs_range_unlock(rl);
1715 
1716                 if (error == 0) {
1717                         /*
1718                          * If the write-cache is disabled or 'sync' property
1719                          * is set to 'always' then treat this as a synchronous
1720                          * operation (i.e. commit to zil).
1721                          */
1722                         if (!(zv->zv_flags & ZVOL_WCE) ||
1723                             (zv->zv_objset->os_sync == ZFS_SYNC_ALWAYS))
1724                                 zil_commit(zv->zv_zilog, ZVOL_OBJ);
1725 
1726                         /*
1727                          * If the caller really wants synchronous writes, and
1728                          * can't wait for them, don't return until the write
1729                          * is done.
1730                          */
1731                         if (df.df_flags & DF_WAIT_SYNC) {
1732                                 txg_wait_synced(
1733                                     dmu_objset_pool(zv->zv_objset), 0);
1734                         }
1735                 }
1736                 break;
1737         }
1738 
1739         default:
1740                 error = ENOTTY;
1741                 break;
1742 
1743         }
1744         mutex_exit(&zfsdev_state_lock);
1745         return (error);
1746 }
1747 
1748 int
1749 zvol_busy(void)
1750 {
1751         return (zvol_minors != 0);
1752 }
1753 
1754 void
1755 zvol_init(void)
1756 {
1757         VERIFY(ddi_soft_state_init(&zfsdev_state, sizeof (zfs_soft_state_t),
1758             1) == 0);
1759         mutex_init(&zfsdev_state_lock, NULL, MUTEX_DEFAULT, NULL);
1760 }
1761 
1762 void
1763 zvol_fini(void)
1764 {
1765         mutex_destroy(&zfsdev_state_lock);
1766         ddi_soft_state_fini(&zfsdev_state);
1767 }
1768 
1769 static int
1770 zvol_dump_init(zvol_state_t *zv, boolean_t resize)
1771 {
1772         dmu_tx_t *tx;
1773         int error = 0;
1774         objset_t *os = zv->zv_objset;
1775         nvlist_t *nv = NULL;
1776         uint64_t version = spa_version(dmu_objset_spa(zv->zv_objset));
1777 
1778         ASSERT(MUTEX_HELD(&zfsdev_state_lock));
1779         error = dmu_free_long_range(zv->zv_objset, ZVOL_OBJ, 0,
1780             DMU_OBJECT_END);
1781         /* wait for dmu_free_long_range to actually free the blocks */
1782         txg_wait_synced(dmu_objset_pool(zv->zv_objset), 0);
1783 
1784         tx = dmu_tx_create(os);
1785         dmu_tx_hold_zap(tx, ZVOL_ZAP_OBJ, TRUE, NULL);
1786         dmu_tx_hold_bonus(tx, ZVOL_OBJ);
1787         error = dmu_tx_assign(tx, TXG_WAIT);
1788         if (error) {
1789                 dmu_tx_abort(tx);
1790                 return (error);
1791         }
1792 
1793         /*
1794          * If we are resizing the dump device then we only need to
1795          * update the refreservation to match the newly updated
1796          * zvolsize. Otherwise, we save off the original state of the
1797          * zvol so that we can restore them if the zvol is ever undumpified.
1798          */
1799         if (resize) {
1800                 error = zap_update(os, ZVOL_ZAP_OBJ,
1801                     zfs_prop_to_name(ZFS_PROP_REFRESERVATION), 8, 1,
1802                     &zv->zv_volsize, tx);
1803         } else {
1804                 uint64_t checksum, compress, refresrv, vbs, dedup;
1805 
1806                 error = dsl_prop_get_integer(zv->zv_name,
1807                     zfs_prop_to_name(ZFS_PROP_COMPRESSION), &compress, NULL);
1808                 error = error ? error : dsl_prop_get_integer(zv->zv_name,
1809                     zfs_prop_to_name(ZFS_PROP_CHECKSUM), &checksum, NULL);
1810                 error = error ? error : dsl_prop_get_integer(zv->zv_name,
1811                     zfs_prop_to_name(ZFS_PROP_REFRESERVATION), &refresrv, NULL);
1812                 error = error ? error : dsl_prop_get_integer(zv->zv_name,
1813                     zfs_prop_to_name(ZFS_PROP_VOLBLOCKSIZE), &vbs, NULL);
1814                 if (version >= SPA_VERSION_DEDUP) {
1815                         error = error ? error :
1816                             dsl_prop_get_integer(zv->zv_name,
1817                             zfs_prop_to_name(ZFS_PROP_DEDUP), &dedup, NULL);
1818                 }
1819 
1820                 error = error ? error : zap_update(os, ZVOL_ZAP_OBJ,
1821                     zfs_prop_to_name(ZFS_PROP_COMPRESSION), 8, 1,
1822                     &compress, tx);
1823                 error = error ? error : zap_update(os, ZVOL_ZAP_OBJ,
1824                     zfs_prop_to_name(ZFS_PROP_CHECKSUM), 8, 1, &checksum, tx);
1825                 error = error ? error : zap_update(os, ZVOL_ZAP_OBJ,
1826                     zfs_prop_to_name(ZFS_PROP_REFRESERVATION), 8, 1,
1827                     &refresrv, tx);
1828                 error = error ? error : zap_update(os, ZVOL_ZAP_OBJ,
1829                     zfs_prop_to_name(ZFS_PROP_VOLBLOCKSIZE), 8, 1,
1830                     &vbs, tx);
1831                 error = error ? error : dmu_object_set_blocksize(
1832                     os, ZVOL_OBJ, SPA_MAXBLOCKSIZE, 0, tx);
1833                 if (version >= SPA_VERSION_DEDUP) {
1834                         error = error ? error : zap_update(os, ZVOL_ZAP_OBJ,
1835                             zfs_prop_to_name(ZFS_PROP_DEDUP), 8, 1,
1836                             &dedup, tx);
1837                 }
1838                 if (error == 0)
1839                         zv->zv_volblocksize = SPA_MAXBLOCKSIZE;
1840         }
1841         dmu_tx_commit(tx);
1842 
1843         /*
1844          * We only need update the zvol's property if we are initializing
1845          * the dump area for the first time.
1846          */
1847         if (!resize) {
1848                 VERIFY(nvlist_alloc(&nv, NV_UNIQUE_NAME, KM_SLEEP) == 0);
1849                 VERIFY(nvlist_add_uint64(nv,
1850                     zfs_prop_to_name(ZFS_PROP_REFRESERVATION), 0) == 0);
1851                 VERIFY(nvlist_add_uint64(nv,
1852                     zfs_prop_to_name(ZFS_PROP_COMPRESSION),
1853                     ZIO_COMPRESS_OFF) == 0);
1854                 VERIFY(nvlist_add_uint64(nv,
1855                     zfs_prop_to_name(ZFS_PROP_CHECKSUM),
1856                     ZIO_CHECKSUM_OFF) == 0);
1857                 if (version >= SPA_VERSION_DEDUP) {
1858                         VERIFY(nvlist_add_uint64(nv,
1859                             zfs_prop_to_name(ZFS_PROP_DEDUP),
1860                             ZIO_CHECKSUM_OFF) == 0);
1861                 }
1862 
1863                 error = zfs_set_prop_nvlist(zv->zv_name, ZPROP_SRC_LOCAL,
1864                     nv, NULL);
1865                 nvlist_free(nv);
1866 
1867                 if (error)
1868                         return (error);
1869         }
1870 
1871         /* Allocate the space for the dump */
1872         error = zvol_prealloc(zv);
1873         return (error);
1874 }
1875 
1876 static int
1877 zvol_dumpify(zvol_state_t *zv)
1878 {
1879         int error = 0;
1880         uint64_t dumpsize = 0;
1881         dmu_tx_t *tx;
1882         objset_t *os = zv->zv_objset;
1883 
1884         if (zv->zv_flags & ZVOL_RDONLY)
1885                 return (EROFS);
1886 
1887         if (zap_lookup(zv->zv_objset, ZVOL_ZAP_OBJ, ZVOL_DUMPSIZE,
1888             8, 1, &dumpsize) != 0 || dumpsize != zv->zv_volsize) {
1889                 boolean_t resize = (dumpsize > 0);
1890 
1891                 if ((error = zvol_dump_init(zv, resize)) != 0) {
1892                         (void) zvol_dump_fini(zv);
1893                         return (error);
1894                 }
1895         }
1896 
1897         /*
1898          * Build up our lba mapping.
1899          */
1900         error = zvol_get_lbas(zv);
1901         if (error) {
1902                 (void) zvol_dump_fini(zv);
1903                 return (error);
1904         }
1905 
1906         tx = dmu_tx_create(os);
1907         dmu_tx_hold_zap(tx, ZVOL_ZAP_OBJ, TRUE, NULL);
1908         error = dmu_tx_assign(tx, TXG_WAIT);
1909         if (error) {
1910                 dmu_tx_abort(tx);
1911                 (void) zvol_dump_fini(zv);
1912                 return (error);
1913         }
1914 
1915         zv->zv_flags |= ZVOL_DUMPIFIED;
1916         error = zap_update(os, ZVOL_ZAP_OBJ, ZVOL_DUMPSIZE, 8, 1,
1917             &zv->zv_volsize, tx);
1918         dmu_tx_commit(tx);
1919 
1920         if (error) {
1921                 (void) zvol_dump_fini(zv);
1922                 return (error);
1923         }
1924 
1925         txg_wait_synced(dmu_objset_pool(os), 0);
1926         return (0);
1927 }
1928 
1929 static int
1930 zvol_dump_fini(zvol_state_t *zv)
1931 {
1932         dmu_tx_t *tx;
1933         objset_t *os = zv->zv_objset;
1934         nvlist_t *nv;
1935         int error = 0;
1936         uint64_t checksum, compress, refresrv, vbs, dedup;
1937         uint64_t version = spa_version(dmu_objset_spa(zv->zv_objset));
1938 
1939         /*
1940          * Attempt to restore the zvol back to its pre-dumpified state.
1941          * This is a best-effort attempt as it's possible that not all
1942          * of these properties were initialized during the dumpify process
1943          * (i.e. error during zvol_dump_init).
1944          */
1945 
1946         tx = dmu_tx_create(os);
1947         dmu_tx_hold_zap(tx, ZVOL_ZAP_OBJ, TRUE, NULL);
1948         error = dmu_tx_assign(tx, TXG_WAIT);
1949         if (error) {
1950                 dmu_tx_abort(tx);
1951                 return (error);
1952         }
1953         (void) zap_remove(os, ZVOL_ZAP_OBJ, ZVOL_DUMPSIZE, tx);
1954         dmu_tx_commit(tx);
1955 
1956         (void) zap_lookup(zv->zv_objset, ZVOL_ZAP_OBJ,
1957             zfs_prop_to_name(ZFS_PROP_CHECKSUM), 8, 1, &checksum);
1958         (void) zap_lookup(zv->zv_objset, ZVOL_ZAP_OBJ,
1959             zfs_prop_to_name(ZFS_PROP_COMPRESSION), 8, 1, &compress);
1960         (void) zap_lookup(zv->zv_objset, ZVOL_ZAP_OBJ,
1961             zfs_prop_to_name(ZFS_PROP_REFRESERVATION), 8, 1, &refresrv);
1962         (void) zap_lookup(zv->zv_objset, ZVOL_ZAP_OBJ,
1963             zfs_prop_to_name(ZFS_PROP_VOLBLOCKSIZE), 8, 1, &vbs);
1964 
1965         VERIFY(nvlist_alloc(&nv, NV_UNIQUE_NAME, KM_SLEEP) == 0);
1966         (void) nvlist_add_uint64(nv,
1967             zfs_prop_to_name(ZFS_PROP_CHECKSUM), checksum);
1968         (void) nvlist_add_uint64(nv,
1969             zfs_prop_to_name(ZFS_PROP_COMPRESSION), compress);
1970         (void) nvlist_add_uint64(nv,
1971             zfs_prop_to_name(ZFS_PROP_REFRESERVATION), refresrv);
1972         if (version >= SPA_VERSION_DEDUP &&
1973             zap_lookup(zv->zv_objset, ZVOL_ZAP_OBJ,
1974             zfs_prop_to_name(ZFS_PROP_DEDUP), 8, 1, &dedup) == 0) {
1975                 (void) nvlist_add_uint64(nv,
1976                     zfs_prop_to_name(ZFS_PROP_DEDUP), dedup);
1977         }
1978         (void) zfs_set_prop_nvlist(zv->zv_name, ZPROP_SRC_LOCAL,
1979             nv, NULL);
1980         nvlist_free(nv);
1981 
1982         zvol_free_extents(zv);
1983         zv->zv_flags &= ~ZVOL_DUMPIFIED;
1984         (void) dmu_free_long_range(os, ZVOL_OBJ, 0, DMU_OBJECT_END);
1985         /* wait for dmu_free_long_range to actually free the blocks */
1986         txg_wait_synced(dmu_objset_pool(zv->zv_objset), 0);
1987         tx = dmu_tx_create(os);
1988         dmu_tx_hold_bonus(tx, ZVOL_OBJ);
1989         error = dmu_tx_assign(tx, TXG_WAIT);
1990         if (error) {
1991                 dmu_tx_abort(tx);
1992                 return (error);
1993         }
1994         if (dmu_object_set_blocksize(os, ZVOL_OBJ, vbs, 0, tx) == 0)
1995                 zv->zv_volblocksize = vbs;
1996         dmu_tx_commit(tx);
1997 
1998         return (0);
1999 }