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  * Copyright (c) 2012, 2015 by Delphix. All rights reserved.
  24  * Copyright 2016 Nexenta Systems, Inc.  All rights reserved.
  25  * Copyright (c) 2013 Joyent, Inc.  All rights reserved.
  26  */
  27 
  28 #include <sys/zfs_context.h>
  29 #include <sys/spa_impl.h>
  30 #include <sys/refcount.h>
  31 #include <sys/vdev_disk.h>
  32 #include <sys/vdev_impl.h>
  33 #include <sys/abd.h>
  34 #include <sys/fs/zfs.h>
  35 #include <sys/zio.h>
  36 #include <sys/sunldi.h>
  37 #include <sys/efi_partition.h>
  38 #include <sys/fm/fs/zfs.h>
  39 
  40 /*
  41  * Virtual device vector for disks.
  42  */
  43 
  44 extern ldi_ident_t zfs_li;
  45 
  46 static void vdev_disk_close(vdev_t *);
  47 
  48 typedef struct vdev_disk_ldi_cb {
  49         list_node_t             lcb_next;
  50         ldi_callback_id_t       lcb_id;
  51 } vdev_disk_ldi_cb_t;
  52 
  53 static void
  54 vdev_disk_alloc(vdev_t *vd)
  55 {
  56         vdev_disk_t *dvd;
  57 
  58         dvd = vd->vdev_tsd = kmem_zalloc(sizeof (vdev_disk_t), KM_SLEEP);
  59         /*
  60          * Create the LDI event callback list.
  61          */
  62         list_create(&dvd->vd_ldi_cbs, sizeof (vdev_disk_ldi_cb_t),
  63             offsetof(vdev_disk_ldi_cb_t, lcb_next));
  64 }
  65 
  66 static void
  67 vdev_disk_free(vdev_t *vd)
  68 {
  69         vdev_disk_t *dvd = vd->vdev_tsd;
  70         vdev_disk_ldi_cb_t *lcb;
  71 
  72         if (dvd == NULL)
  73                 return;
  74 
  75         /*
  76          * We have already closed the LDI handle. Clean up the LDI event
  77          * callbacks and free vd->vdev_tsd.
  78          */
  79         while ((lcb = list_head(&dvd->vd_ldi_cbs)) != NULL) {
  80                 list_remove(&dvd->vd_ldi_cbs, lcb);
  81                 (void) ldi_ev_remove_callbacks(lcb->lcb_id);
  82                 kmem_free(lcb, sizeof (vdev_disk_ldi_cb_t));
  83         }
  84         list_destroy(&dvd->vd_ldi_cbs);
  85         kmem_free(dvd, sizeof (vdev_disk_t));
  86         vd->vdev_tsd = NULL;
  87 }
  88 
  89 /* ARGSUSED */
  90 static int
  91 vdev_disk_off_notify(ldi_handle_t lh, ldi_ev_cookie_t ecookie, void *arg,
  92     void *ev_data)
  93 {
  94         vdev_t *vd = (vdev_t *)arg;
  95         vdev_disk_t *dvd = vd->vdev_tsd;
  96 
  97         /*
  98          * Ignore events other than offline.
  99          */
 100         if (strcmp(ldi_ev_get_type(ecookie), LDI_EV_OFFLINE) != 0)
 101                 return (LDI_EV_SUCCESS);
 102 
 103         /*
 104          * All LDI handles must be closed for the state change to succeed, so
 105          * call on vdev_disk_close() to do this.
 106          *
 107          * We inform vdev_disk_close that it is being called from offline
 108          * notify context so it will defer cleanup of LDI event callbacks and
 109          * freeing of vd->vdev_tsd to the offline finalize or a reopen.
 110          */
 111         dvd->vd_ldi_offline = B_TRUE;
 112         vdev_disk_close(vd);
 113 
 114         /*
 115          * Now that the device is closed, request that the spa_async_thread
 116          * mark the device as REMOVED and notify FMA of the removal.
 117          */
 118         zfs_post_remove(vd->vdev_spa, vd);
 119         vd->vdev_remove_wanted = B_TRUE;
 120         spa_async_request(vd->vdev_spa, SPA_ASYNC_REMOVE);
 121 
 122         return (LDI_EV_SUCCESS);
 123 }
 124 
 125 /* ARGSUSED */
 126 static void
 127 vdev_disk_off_finalize(ldi_handle_t lh, ldi_ev_cookie_t ecookie,
 128     int ldi_result, void *arg, void *ev_data)
 129 {
 130         vdev_t *vd = (vdev_t *)arg;
 131 
 132         /*
 133          * Ignore events other than offline.
 134          */
 135         if (strcmp(ldi_ev_get_type(ecookie), LDI_EV_OFFLINE) != 0)
 136                 return;
 137 
 138         /*
 139          * We have already closed the LDI handle in notify.
 140          * Clean up the LDI event callbacks and free vd->vdev_tsd.
 141          */
 142         vdev_disk_free(vd);
 143 
 144         /*
 145          * Request that the vdev be reopened if the offline state change was
 146          * unsuccessful.
 147          */
 148         if (ldi_result != LDI_EV_SUCCESS) {
 149                 vd->vdev_probe_wanted = B_TRUE;
 150                 spa_async_request(vd->vdev_spa, SPA_ASYNC_PROBE);
 151         }
 152 }
 153 
 154 static ldi_ev_callback_t vdev_disk_off_callb = {
 155         .cb_vers = LDI_EV_CB_VERS,
 156         .cb_notify = vdev_disk_off_notify,
 157         .cb_finalize = vdev_disk_off_finalize
 158 };
 159 
 160 /* ARGSUSED */
 161 static void
 162 vdev_disk_dgrd_finalize(ldi_handle_t lh, ldi_ev_cookie_t ecookie,
 163     int ldi_result, void *arg, void *ev_data)
 164 {
 165         vdev_t *vd = (vdev_t *)arg;
 166 
 167         /*
 168          * Ignore events other than degrade.
 169          */
 170         if (strcmp(ldi_ev_get_type(ecookie), LDI_EV_DEGRADE) != 0)
 171                 return;
 172 
 173         /*
 174          * Degrade events always succeed. Mark the vdev as degraded.
 175          * This status is purely informative for the user.
 176          */
 177         (void) vdev_degrade(vd->vdev_spa, vd->vdev_guid, 0);
 178 }
 179 
 180 static ldi_ev_callback_t vdev_disk_dgrd_callb = {
 181         .cb_vers = LDI_EV_CB_VERS,
 182         .cb_notify = NULL,
 183         .cb_finalize = vdev_disk_dgrd_finalize
 184 };
 185 
 186 static void
 187 vdev_disk_hold(vdev_t *vd)
 188 {
 189         ddi_devid_t devid;
 190         char *minor;
 191 
 192         ASSERT(spa_config_held(vd->vdev_spa, SCL_STATE, RW_WRITER));
 193 
 194         /*
 195          * We must have a pathname, and it must be absolute.
 196          */
 197         if (vd->vdev_path == NULL || vd->vdev_path[0] != '/')
 198                 return;
 199 
 200         /*
 201          * Only prefetch path and devid info if the device has
 202          * never been opened.
 203          */
 204         if (vd->vdev_tsd != NULL)
 205                 return;
 206 
 207         if (vd->vdev_wholedisk == -1ULL) {
 208                 size_t len = strlen(vd->vdev_path) + 3;
 209                 char *buf = kmem_alloc(len, KM_SLEEP);
 210 
 211                 (void) snprintf(buf, len, "%ss0", vd->vdev_path);
 212 
 213                 (void) ldi_vp_from_name(buf, &vd->vdev_name_vp);
 214                 kmem_free(buf, len);
 215         }
 216 
 217         if (vd->vdev_name_vp == NULL)
 218                 (void) ldi_vp_from_name(vd->vdev_path, &vd->vdev_name_vp);
 219 
 220         if (vd->vdev_devid != NULL &&
 221             ddi_devid_str_decode(vd->vdev_devid, &devid, &minor) == 0) {
 222                 (void) ldi_vp_from_devid(devid, minor, &vd->vdev_devid_vp);
 223                 ddi_devid_str_free(minor);
 224                 ddi_devid_free(devid);
 225         }
 226 }
 227 
 228 static void
 229 vdev_disk_rele(vdev_t *vd)
 230 {
 231         ASSERT(spa_config_held(vd->vdev_spa, SCL_STATE, RW_WRITER));
 232 
 233         if (vd->vdev_name_vp) {
 234                 VN_RELE_ASYNC(vd->vdev_name_vp,
 235                     dsl_pool_vnrele_taskq(vd->vdev_spa->spa_dsl_pool));
 236                 vd->vdev_name_vp = NULL;
 237         }
 238         if (vd->vdev_devid_vp) {
 239                 VN_RELE_ASYNC(vd->vdev_devid_vp,
 240                     dsl_pool_vnrele_taskq(vd->vdev_spa->spa_dsl_pool));
 241                 vd->vdev_devid_vp = NULL;
 242         }
 243 }
 244 
 245 /*
 246  * We want to be loud in DEBUG kernels when DKIOCGMEDIAINFOEXT fails, or when
 247  * even a fallback to DKIOCGMEDIAINFO fails.
 248  */
 249 #ifdef DEBUG
 250 #define VDEV_DEBUG(...) cmn_err(CE_NOTE, __VA_ARGS__)
 251 #else
 252 #define VDEV_DEBUG(...) /* Nothing... */
 253 #endif
 254 
 255 static int
 256 vdev_disk_open(vdev_t *vd, uint64_t *psize, uint64_t *max_psize,
 257     uint64_t *ashift)
 258 {
 259         spa_t *spa = vd->vdev_spa;
 260         vdev_disk_t *dvd = vd->vdev_tsd;
 261         ldi_ev_cookie_t ecookie;
 262         vdev_disk_ldi_cb_t *lcb;
 263         union {
 264                 struct dk_minfo_ext ude;
 265                 struct dk_minfo ud;
 266         } dks;
 267         struct dk_minfo_ext *dkmext = &dks.ude;
 268         struct dk_minfo *dkm = &dks.ud;
 269         int error;
 270         dev_t dev;
 271         int otyp;
 272         boolean_t validate_devid = B_FALSE;
 273         ddi_devid_t devid;
 274         uint64_t capacity = 0, blksz = 0, pbsize;
 275 
 276         /*
 277          * We must have a pathname, and it must be absolute.
 278          */
 279         if (vd->vdev_path == NULL || vd->vdev_path[0] != '/') {
 280                 vd->vdev_stat.vs_aux = VDEV_AUX_BAD_LABEL;
 281                 return (SET_ERROR(EINVAL));
 282         }
 283 
 284         /*
 285          * Reopen the device if it's not currently open. Otherwise,
 286          * just update the physical size of the device.
 287          */
 288         if (dvd != NULL) {
 289                 if (dvd->vd_ldi_offline && dvd->vd_lh == NULL) {
 290                         /*
 291                          * If we are opening a device in its offline notify
 292                          * context, the LDI handle was just closed. Clean
 293                          * up the LDI event callbacks and free vd->vdev_tsd.
 294                          */
 295                         vdev_disk_free(vd);
 296                 } else {
 297                         ASSERT(vd->vdev_reopening);
 298                         goto skip_open;
 299                 }
 300         }
 301 
 302         /*
 303          * Create vd->vdev_tsd.
 304          */
 305         vdev_disk_alloc(vd);
 306         dvd = vd->vdev_tsd;
 307 
 308         /*
 309          * When opening a disk device, we want to preserve the user's original
 310          * intent.  We always want to open the device by the path the user gave
 311          * us, even if it is one of multiple paths to the same device.  But we
 312          * also want to be able to survive disks being removed/recabled.
 313          * Therefore the sequence of opening devices is:
 314          *
 315          * 1. Try opening the device by path.  For legacy pools without the
 316          *    'whole_disk' property, attempt to fix the path by appending 's0'.
 317          *
 318          * 2. If the devid of the device matches the stored value, return
 319          *    success.
 320          *
 321          * 3. Otherwise, the device may have moved.  Try opening the device
 322          *    by the devid instead.
 323          */
 324         if (vd->vdev_devid != NULL) {
 325                 if (ddi_devid_str_decode(vd->vdev_devid, &dvd->vd_devid,
 326                     &dvd->vd_minor) != 0) {
 327                         vd->vdev_stat.vs_aux = VDEV_AUX_BAD_LABEL;
 328                         return (SET_ERROR(EINVAL));
 329                 }
 330         }
 331 
 332         error = EINVAL;         /* presume failure */
 333 
 334         if (vd->vdev_path != NULL) {
 335 
 336                 if (vd->vdev_wholedisk == -1ULL) {
 337                         size_t len = strlen(vd->vdev_path) + 3;
 338                         char *buf = kmem_alloc(len, KM_SLEEP);
 339 
 340                         (void) snprintf(buf, len, "%ss0", vd->vdev_path);
 341 
 342                         error = ldi_open_by_name(buf, spa_mode(spa), kcred,
 343                             &dvd->vd_lh, zfs_li);
 344                         if (error == 0) {
 345                                 spa_strfree(vd->vdev_path);
 346                                 vd->vdev_path = buf;
 347                                 vd->vdev_wholedisk = 1ULL;
 348                         } else {
 349                                 kmem_free(buf, len);
 350                         }
 351                 }
 352 
 353                 /*
 354                  * If we have not yet opened the device, try to open it by the
 355                  * specified path.
 356                  */
 357                 if (error != 0) {
 358                         error = ldi_open_by_name(vd->vdev_path, spa_mode(spa),
 359                             kcred, &dvd->vd_lh, zfs_li);
 360                 }
 361 
 362                 /*
 363                  * Compare the devid to the stored value.
 364                  */
 365                 if (error == 0 && vd->vdev_devid != NULL &&
 366                     ldi_get_devid(dvd->vd_lh, &devid) == 0) {
 367                         if (ddi_devid_compare(devid, dvd->vd_devid) != 0) {
 368                                 error = SET_ERROR(EINVAL);
 369                                 (void) ldi_close(dvd->vd_lh, spa_mode(spa),
 370                                     kcred);
 371                                 dvd->vd_lh = NULL;
 372                         }
 373                         ddi_devid_free(devid);
 374                 }
 375 
 376                 /*
 377                  * If we succeeded in opening the device, but 'vdev_wholedisk'
 378                  * is not yet set, then this must be a slice.
 379                  */
 380                 if (error == 0 && vd->vdev_wholedisk == -1ULL)
 381                         vd->vdev_wholedisk = 0;
 382         }
 383 
 384         /*
 385          * If we were unable to open by path, or the devid check fails, open by
 386          * devid instead.
 387          */
 388         if (error != 0 && vd->vdev_devid != NULL) {
 389                 error = ldi_open_by_devid(dvd->vd_devid, dvd->vd_minor,
 390                     spa_mode(spa), kcred, &dvd->vd_lh, zfs_li);
 391         }
 392 
 393         /*
 394          * If all else fails, then try opening by physical path (if available)
 395          * or the logical path (if we failed due to the devid check).  While not
 396          * as reliable as the devid, this will give us something, and the higher
 397          * level vdev validation will prevent us from opening the wrong device.
 398          */
 399         if (error) {
 400                 if (vd->vdev_devid != NULL)
 401                         validate_devid = B_TRUE;
 402 
 403                 if (vd->vdev_physpath != NULL &&
 404                     (dev = ddi_pathname_to_dev_t(vd->vdev_physpath)) != NODEV)
 405                         error = ldi_open_by_dev(&dev, OTYP_BLK, spa_mode(spa),
 406                             kcred, &dvd->vd_lh, zfs_li);
 407 
 408                 /*
 409                  * Note that we don't support the legacy auto-wholedisk support
 410                  * as above.  This hasn't been used in a very long time and we
 411                  * don't need to propagate its oddities to this edge condition.
 412                  */
 413                 if (error && vd->vdev_path != NULL)
 414                         error = ldi_open_by_name(vd->vdev_path, spa_mode(spa),
 415                             kcred, &dvd->vd_lh, zfs_li);
 416         }
 417 
 418         if (error) {
 419                 vd->vdev_stat.vs_aux = VDEV_AUX_OPEN_FAILED;
 420                 return (error);
 421         }
 422 
 423         /*
 424          * Now that the device has been successfully opened, update the devid
 425          * if necessary.
 426          */
 427         if (validate_devid && spa_writeable(spa) &&
 428             ldi_get_devid(dvd->vd_lh, &devid) == 0) {
 429                 if (ddi_devid_compare(devid, dvd->vd_devid) != 0) {
 430                         char *vd_devid;
 431 
 432                         vd_devid = ddi_devid_str_encode(devid, dvd->vd_minor);
 433                         zfs_dbgmsg("vdev %s: update devid from %s, "
 434                             "to %s", vd->vdev_path, vd->vdev_devid, vd_devid);
 435                         spa_strfree(vd->vdev_devid);
 436                         vd->vdev_devid = spa_strdup(vd_devid);
 437                         ddi_devid_str_free(vd_devid);
 438                 }
 439                 ddi_devid_free(devid);
 440         }
 441 
 442         /*
 443          * Once a device is opened, verify that the physical device path (if
 444          * available) is up to date.
 445          */
 446         if (ldi_get_dev(dvd->vd_lh, &dev) == 0 &&
 447             ldi_get_otyp(dvd->vd_lh, &otyp) == 0) {
 448                 char *physpath, *minorname;
 449 
 450                 physpath = kmem_alloc(MAXPATHLEN, KM_SLEEP);
 451                 minorname = NULL;
 452                 if (ddi_dev_pathname(dev, otyp, physpath) == 0 &&
 453                     ldi_get_minor_name(dvd->vd_lh, &minorname) == 0 &&
 454                     (vd->vdev_physpath == NULL ||
 455                     strcmp(vd->vdev_physpath, physpath) != 0)) {
 456                         if (vd->vdev_physpath)
 457                                 spa_strfree(vd->vdev_physpath);
 458                         (void) strlcat(physpath, ":", MAXPATHLEN);
 459                         (void) strlcat(physpath, minorname, MAXPATHLEN);
 460                         vd->vdev_physpath = spa_strdup(physpath);
 461                 }
 462                 if (minorname)
 463                         kmem_free(minorname, strlen(minorname) + 1);
 464                 kmem_free(physpath, MAXPATHLEN);
 465         }
 466 
 467         /*
 468          * Register callbacks for the LDI offline event.
 469          */
 470         if (ldi_ev_get_cookie(dvd->vd_lh, LDI_EV_OFFLINE, &ecookie) ==
 471             LDI_EV_SUCCESS) {
 472                 lcb = kmem_zalloc(sizeof (vdev_disk_ldi_cb_t), KM_SLEEP);
 473                 list_insert_tail(&dvd->vd_ldi_cbs, lcb);
 474                 (void) ldi_ev_register_callbacks(dvd->vd_lh, ecookie,
 475                     &vdev_disk_off_callb, (void *) vd, &lcb->lcb_id);
 476         }
 477 
 478         /*
 479          * Register callbacks for the LDI degrade event.
 480          */
 481         if (ldi_ev_get_cookie(dvd->vd_lh, LDI_EV_DEGRADE, &ecookie) ==
 482             LDI_EV_SUCCESS) {
 483                 lcb = kmem_zalloc(sizeof (vdev_disk_ldi_cb_t), KM_SLEEP);
 484                 list_insert_tail(&dvd->vd_ldi_cbs, lcb);
 485                 (void) ldi_ev_register_callbacks(dvd->vd_lh, ecookie,
 486                     &vdev_disk_dgrd_callb, (void *) vd, &lcb->lcb_id);
 487         }
 488 skip_open:
 489         /*
 490          * Determine the actual size of the device.
 491          */
 492         if (ldi_get_size(dvd->vd_lh, psize) != 0) {
 493                 vd->vdev_stat.vs_aux = VDEV_AUX_OPEN_FAILED;
 494                 return (SET_ERROR(EINVAL));
 495         }
 496 
 497         *max_psize = *psize;
 498 
 499         /*
 500          * Determine the device's minimum transfer size.
 501          * If the ioctl isn't supported, assume DEV_BSIZE.
 502          */
 503         if ((error = ldi_ioctl(dvd->vd_lh, DKIOCGMEDIAINFOEXT,
 504             (intptr_t)dkmext, FKIOCTL, kcred, NULL)) == 0) {
 505                 capacity = dkmext->dki_capacity - 1;
 506                 blksz = dkmext->dki_lbsize;
 507                 pbsize = dkmext->dki_pbsize;
 508         } else if ((error = ldi_ioctl(dvd->vd_lh, DKIOCGMEDIAINFO,
 509             (intptr_t)dkm, FKIOCTL, kcred, NULL)) == 0) {
 510                 VDEV_DEBUG(
 511                     "vdev_disk_open(\"%s\"): fallback to DKIOCGMEDIAINFO\n",
 512                     vd->vdev_path);
 513                 capacity = dkm->dki_capacity - 1;
 514                 blksz = dkm->dki_lbsize;
 515                 pbsize = blksz;
 516         } else {
 517                 VDEV_DEBUG("vdev_disk_open(\"%s\"): "
 518                     "both DKIOCGMEDIAINFO{,EXT} calls failed, %d\n",
 519                     vd->vdev_path, error);
 520                 pbsize = DEV_BSIZE;
 521         }
 522 
 523         *ashift = highbit64(MAX(pbsize, SPA_MINBLOCKSIZE)) - 1;
 524 
 525         if (vd->vdev_wholedisk == 1) {
 526                 int wce = 1;
 527 
 528                 if (error == 0) {
 529                         /*
 530                          * If we have the capability to expand, we'd have
 531                          * found out via success from DKIOCGMEDIAINFO{,EXT}.
 532                          * Adjust max_psize upward accordingly since we know
 533                          * we own the whole disk now.
 534                          */
 535                         *max_psize = capacity * blksz;
 536                 }
 537 
 538                 /*
 539                  * Since we own the whole disk, try to enable disk write
 540                  * caching.  We ignore errors because it's OK if we can't do it.
 541                  */
 542                 (void) ldi_ioctl(dvd->vd_lh, DKIOCSETWCE, (intptr_t)&wce,
 543                     FKIOCTL, kcred, NULL);
 544         }
 545 
 546         /*
 547          * Clear the nowritecache bit, so that on a vdev_reopen() we will
 548          * try again.
 549          */
 550         vd->vdev_nowritecache = B_FALSE;
 551 
 552         return (0);
 553 }
 554 
 555 static void
 556 vdev_disk_close(vdev_t *vd)
 557 {
 558         vdev_disk_t *dvd = vd->vdev_tsd;
 559 
 560         if (vd->vdev_reopening || dvd == NULL)
 561                 return;
 562 
 563         if (dvd->vd_minor != NULL) {
 564                 ddi_devid_str_free(dvd->vd_minor);
 565                 dvd->vd_minor = NULL;
 566         }
 567 
 568         if (dvd->vd_devid != NULL) {
 569                 ddi_devid_free(dvd->vd_devid);
 570                 dvd->vd_devid = NULL;
 571         }
 572 
 573         if (dvd->vd_lh != NULL) {
 574                 (void) ldi_close(dvd->vd_lh, spa_mode(vd->vdev_spa), kcred);
 575                 dvd->vd_lh = NULL;
 576         }
 577 
 578         vd->vdev_delayed_close = B_FALSE;
 579         /*
 580          * If we closed the LDI handle due to an offline notify from LDI,
 581          * don't free vd->vdev_tsd or unregister the callbacks here;
 582          * the offline finalize callback or a reopen will take care of it.
 583          */
 584         if (dvd->vd_ldi_offline)
 585                 return;
 586 
 587         vdev_disk_free(vd);
 588 }
 589 
 590 int
 591 vdev_disk_physio(vdev_t *vd, caddr_t data,
 592     size_t size, uint64_t offset, int flags, boolean_t isdump)
 593 {
 594         vdev_disk_t *dvd = vd->vdev_tsd;
 595 
 596         /*
 597          * If the vdev is closed, it's likely in the REMOVED or FAULTED state.
 598          * Nothing to be done here but return failure.
 599          */
 600         if (dvd == NULL || (dvd->vd_ldi_offline && dvd->vd_lh == NULL))
 601                 return (EIO);
 602 
 603         ASSERT(vd->vdev_ops == &vdev_disk_ops);
 604 
 605         /*
 606          * If in the context of an active crash dump, use the ldi_dump(9F)
 607          * call instead of ldi_strategy(9F) as usual.
 608          */
 609         if (isdump) {
 610                 ASSERT3P(dvd, !=, NULL);
 611                 return (ldi_dump(dvd->vd_lh, data, lbtodb(offset),
 612                     lbtodb(size)));
 613         }
 614 
 615         return (vdev_disk_ldi_physio(dvd->vd_lh, data, size, offset, flags));
 616 }
 617 
 618 int
 619 vdev_disk_ldi_physio(ldi_handle_t vd_lh, caddr_t data,
 620     size_t size, uint64_t offset, int flags)
 621 {
 622         buf_t *bp;
 623         int error = 0;
 624 
 625         if (vd_lh == NULL)
 626                 return (SET_ERROR(EINVAL));
 627 
 628         ASSERT(flags & B_READ || flags & B_WRITE);
 629 
 630         bp = getrbuf(KM_SLEEP);
 631         bp->b_flags = flags | B_BUSY | B_NOCACHE | B_FAILFAST;
 632         bp->b_bcount = size;
 633         bp->b_un.b_addr = (void *)data;
 634         bp->b_lblkno = lbtodb(offset);
 635         bp->b_bufsize = size;
 636 
 637         error = ldi_strategy(vd_lh, bp);
 638         ASSERT(error == 0);
 639         if ((error = biowait(bp)) == 0 && bp->b_resid != 0)
 640                 error = SET_ERROR(EIO);
 641         freerbuf(bp);
 642 
 643         return (error);
 644 }
 645 
 646 static void
 647 vdev_disk_io_intr(buf_t *bp)
 648 {
 649         vdev_buf_t *vb = (vdev_buf_t *)bp;
 650         zio_t *zio = vb->vb_io;
 651 
 652         /*
 653          * The rest of the zio stack only deals with EIO, ECKSUM, and ENXIO.
 654          * Rather than teach the rest of the stack about other error
 655          * possibilities (EFAULT, etc), we normalize the error value here.
 656          */
 657         zio->io_error = (geterror(bp) != 0 ? EIO : 0);
 658 
 659         if (zio->io_error == 0 && bp->b_resid != 0)
 660                 zio->io_error = SET_ERROR(EIO);
 661 
 662         if (zio->io_type == ZIO_TYPE_READ) {
 663                 abd_return_buf_copy(zio->io_abd, bp->b_un.b_addr, zio->io_size);
 664         } else {
 665                 abd_return_buf(zio->io_abd, bp->b_un.b_addr, zio->io_size);
 666         }
 667 
 668         kmem_free(vb, sizeof (vdev_buf_t));
 669 
 670         zio_delay_interrupt(zio);
 671 }
 672 
 673 static void
 674 vdev_disk_ioctl_free(zio_t *zio)
 675 {
 676         kmem_free(zio->io_vsd, sizeof (struct dk_callback));
 677 }
 678 
 679 static const zio_vsd_ops_t vdev_disk_vsd_ops = {
 680         vdev_disk_ioctl_free,
 681         zio_vsd_default_cksum_report
 682 };
 683 
 684 static void
 685 vdev_disk_ioctl_done(void *zio_arg, int error)
 686 {
 687         zio_t *zio = zio_arg;
 688 
 689         zio->io_error = error;
 690 
 691         zio_interrupt(zio);
 692 }
 693 
 694 static void
 695 vdev_disk_io_start(zio_t *zio)
 696 {
 697         vdev_t *vd = zio->io_vd;
 698         vdev_disk_t *dvd = vd->vdev_tsd;
 699         vdev_buf_t *vb;
 700         struct dk_callback *dkc;
 701         buf_t *bp;
 702         int error;
 703 
 704         /*
 705          * If the vdev is closed, it's likely in the REMOVED or FAULTED state.
 706          * Nothing to be done here but return failure.
 707          */
 708         if (dvd == NULL || (dvd->vd_ldi_offline && dvd->vd_lh == NULL)) {
 709                 zio->io_error = ENXIO;
 710                 zio_interrupt(zio);
 711                 return;
 712         }
 713 
 714         if (zio->io_type == ZIO_TYPE_IOCTL) {
 715                 /* XXPOLICY */
 716                 if (!vdev_readable(vd)) {
 717                         zio->io_error = SET_ERROR(ENXIO);
 718                         zio_interrupt(zio);
 719                         return;
 720                 }
 721 
 722                 switch (zio->io_cmd) {
 723 
 724                 case DKIOCFLUSHWRITECACHE:
 725 
 726                         if (zfs_nocacheflush)
 727                                 break;
 728 
 729                         if (vd->vdev_nowritecache) {
 730                                 zio->io_error = SET_ERROR(ENOTSUP);
 731                                 break;
 732                         }
 733 
 734                         zio->io_vsd = dkc = kmem_alloc(sizeof (*dkc), KM_SLEEP);
 735                         zio->io_vsd_ops = &vdev_disk_vsd_ops;
 736 
 737                         dkc->dkc_callback = vdev_disk_ioctl_done;
 738                         dkc->dkc_flag = FLUSH_VOLATILE;
 739                         dkc->dkc_cookie = zio;
 740 
 741                         error = ldi_ioctl(dvd->vd_lh, zio->io_cmd,
 742                             (uintptr_t)dkc, FKIOCTL, kcred, NULL);
 743 
 744                         if (error == 0) {
 745                                 /*
 746                                  * The ioctl will be done asychronously,
 747                                  * and will call vdev_disk_ioctl_done()
 748                                  * upon completion.
 749                                  */
 750                                 return;
 751                         }
 752 
 753                         zio->io_error = error;
 754 
 755                         break;
 756 
 757                 default:
 758                         zio->io_error = SET_ERROR(ENOTSUP);
 759                 }
 760 
 761                 zio_execute(zio);
 762                 return;
 763         }
 764 
 765         ASSERT(zio->io_type == ZIO_TYPE_READ || zio->io_type == ZIO_TYPE_WRITE);
 766         zio->io_target_timestamp = zio_handle_io_delay(zio);
 767 
 768         vb = kmem_alloc(sizeof (vdev_buf_t), KM_SLEEP);
 769 
 770         vb->vb_io = zio;
 771         bp = &vb->vb_buf;
 772 
 773         bioinit(bp);
 774         bp->b_flags = B_BUSY | B_NOCACHE |
 775             (zio->io_type == ZIO_TYPE_READ ? B_READ : B_WRITE);
 776         if (!(zio->io_flags & (ZIO_FLAG_IO_RETRY | ZIO_FLAG_TRYHARD)))
 777                 bp->b_flags |= B_FAILFAST;
 778         bp->b_bcount = zio->io_size;
 779 
 780         if (zio->io_type == ZIO_TYPE_READ) {
 781                 bp->b_un.b_addr =
 782                     abd_borrow_buf(zio->io_abd, zio->io_size);
 783         } else {
 784                 bp->b_un.b_addr =
 785                     abd_borrow_buf_copy(zio->io_abd, zio->io_size);
 786         }
 787 
 788         bp->b_lblkno = lbtodb(zio->io_offset);
 789         bp->b_bufsize = zio->io_size;
 790         bp->b_iodone = (int (*)())vdev_disk_io_intr;
 791 
 792         /* ldi_strategy() will return non-zero only on programming errors */
 793         VERIFY(ldi_strategy(dvd->vd_lh, bp) == 0);
 794 }
 795 
 796 static void
 797 vdev_disk_io_done(zio_t *zio)
 798 {
 799         vdev_t *vd = zio->io_vd;
 800 
 801         /*
 802          * If the device returned EIO, then attempt a DKIOCSTATE ioctl to see if
 803          * the device has been removed.  If this is the case, then we trigger an
 804          * asynchronous removal of the device. Otherwise, probe the device and
 805          * make sure it's still accessible.
 806          */
 807         if (zio->io_error == EIO && !vd->vdev_remove_wanted) {
 808                 vdev_disk_t *dvd = vd->vdev_tsd;
 809                 int state = DKIO_NONE;
 810 
 811                 if (ldi_ioctl(dvd->vd_lh, DKIOCSTATE, (intptr_t)&state,
 812                     FKIOCTL, kcred, NULL) == 0 && state != DKIO_INSERTED) {
 813                         /*
 814                          * We post the resource as soon as possible, instead of
 815                          * when the async removal actually happens, because the
 816                          * DE is using this information to discard previous I/O
 817                          * errors.
 818                          */
 819                         zfs_post_remove(zio->io_spa, vd);
 820                         vd->vdev_remove_wanted = B_TRUE;
 821                         spa_async_request(zio->io_spa, SPA_ASYNC_REMOVE);
 822                 } else if (!vd->vdev_delayed_close) {
 823                         vd->vdev_delayed_close = B_TRUE;
 824                 }
 825         }
 826 }
 827 
 828 vdev_ops_t vdev_disk_ops = {
 829         vdev_disk_open,
 830         vdev_disk_close,
 831         vdev_default_asize,
 832         vdev_disk_io_start,
 833         vdev_disk_io_done,
 834         NULL,
 835         vdev_disk_hold,
 836         vdev_disk_rele,
 837         VDEV_TYPE_DISK,         /* name of this vdev type */
 838         B_TRUE                  /* leaf vdev */
 839 };
 840 
 841 /*
 842  * Given the root disk device devid or pathname, read the label from
 843  * the device, and construct a configuration nvlist.
 844  */
 845 int
 846 vdev_disk_read_rootlabel(char *devpath, char *devid, nvlist_t **config)
 847 {
 848         ldi_handle_t vd_lh;
 849         vdev_label_t *label;
 850         uint64_t s, size;
 851         int l;
 852         ddi_devid_t tmpdevid;
 853         int error = -1;
 854         char *minor_name;
 855 
 856         /*
 857          * Read the device label and build the nvlist.
 858          */
 859         if (devid != NULL && ddi_devid_str_decode(devid, &tmpdevid,
 860             &minor_name) == 0) {
 861                 error = ldi_open_by_devid(tmpdevid, minor_name,
 862                     FREAD, kcred, &vd_lh, zfs_li);
 863                 ddi_devid_free(tmpdevid);
 864                 ddi_devid_str_free(minor_name);
 865         }
 866 
 867         if (error && (error = ldi_open_by_name(devpath, FREAD, kcred, &vd_lh,
 868             zfs_li)))
 869                 return (error);
 870 
 871         if (ldi_get_size(vd_lh, &s)) {
 872                 (void) ldi_close(vd_lh, FREAD, kcred);
 873                 return (SET_ERROR(EIO));
 874         }
 875 
 876         size = P2ALIGN_TYPED(s, sizeof (vdev_label_t), uint64_t);
 877         label = kmem_alloc(sizeof (vdev_label_t), KM_SLEEP);
 878 
 879         *config = NULL;
 880         for (l = 0; l < VDEV_LABELS; l++) {
 881                 uint64_t offset, state, txg = 0;
 882 
 883                 /* read vdev label */
 884                 offset = vdev_label_offset(size, l, 0);
 885                 if (vdev_disk_ldi_physio(vd_lh, (caddr_t)label,
 886                     VDEV_SKIP_SIZE + VDEV_PHYS_SIZE, offset, B_READ) != 0)
 887                         continue;
 888 
 889                 if (nvlist_unpack(label->vl_vdev_phys.vp_nvlist,
 890                     sizeof (label->vl_vdev_phys.vp_nvlist), config, 0) != 0) {
 891                         *config = NULL;
 892                         continue;
 893                 }
 894 
 895                 if (nvlist_lookup_uint64(*config, ZPOOL_CONFIG_POOL_STATE,
 896                     &state) != 0 || state >= POOL_STATE_DESTROYED) {
 897                         nvlist_free(*config);
 898                         *config = NULL;
 899                         continue;
 900                 }
 901 
 902                 if (nvlist_lookup_uint64(*config, ZPOOL_CONFIG_POOL_TXG,
 903                     &txg) != 0 || txg == 0) {
 904                         nvlist_free(*config);
 905                         *config = NULL;
 906                         continue;
 907                 }
 908 
 909                 break;
 910         }
 911 
 912         kmem_free(label, sizeof (vdev_label_t));
 913         (void) ldi_close(vd_lh, FREAD, kcred);
 914         if (*config == NULL)
 915                 error = SET_ERROR(EIDRM);
 916 
 917         return (error);
 918 }