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      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 /*
     23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
     24  * Use is subject to license terms.
     25  */
     26 
     27 #pragma ident	"%Z%%M%	%I%	%E% SMI"
     28 
     29 #include <sys/zfs_context.h>
     30 #include <sys/fm/fs/zfs.h>
     31 #include <sys/spa.h>
     32 #include <sys/spa_impl.h>
     33 #include <sys/dmu.h>
     34 #include <sys/dmu_tx.h>
     35 #include <sys/vdev_impl.h>
     36 #include <sys/uberblock_impl.h>
     37 #include <sys/metaslab.h>
     38 #include <sys/metaslab_impl.h>
     39 #include <sys/space_map.h>
     40 #include <sys/zio.h>
     41 #include <sys/zap.h>
     42 #include <sys/fs/zfs.h>
     43 #include <sys/arc.h>
     44 
     45 /*
     46  * Virtual device management.
     47  */
     48 
     49 static vdev_ops_t *vdev_ops_table[] = {
     50 	&vdev_root_ops,
     51 	&vdev_raidz_ops,
     52 	&vdev_mirror_ops,
     53 	&vdev_replacing_ops,
     54 	&vdev_spare_ops,
     55 	&vdev_disk_ops,
     56 	&vdev_file_ops,
     57 	&vdev_missing_ops,
     58 	NULL
     59 };
     60 
     61 /* maximum scrub/resilver I/O queue */
     62 int zfs_scrub_limit = 70;
     63 
     64 /*
     65  * Given a vdev type, return the appropriate ops vector.
     66  */
     67 static vdev_ops_t *
     68 vdev_getops(const char *type)
     69 {
     70 	vdev_ops_t *ops, **opspp;
     71 
     72 	for (opspp = vdev_ops_table; (ops = *opspp) != NULL; opspp++)
     73 		if (strcmp(ops->vdev_op_type, type) == 0)
     74 			break;
     75 
     76 	return (ops);
     77 }
     78 
     79 /*
     80  * Default asize function: return the MAX of psize with the asize of
     81  * all children.  This is what's used by anything other than RAID-Z.
     82  */
     83 uint64_t
     84 vdev_default_asize(vdev_t *vd, uint64_t psize)
     85 {
     86 	uint64_t asize = P2ROUNDUP(psize, 1ULL << vd->vdev_top->vdev_ashift);
     87 	uint64_t csize;
     88 	uint64_t c;
     89 
     90 	for (c = 0; c < vd->vdev_children; c++) {
     91 		csize = vdev_psize_to_asize(vd->vdev_child[c], psize);
     92 		asize = MAX(asize, csize);
     93 	}
     94 
     95 	return (asize);
     96 }
     97 
     98 /*
     99  * Get the replaceable or attachable device size.
    100  * If the parent is a mirror or raidz, the replaceable size is the minimum
    101  * psize of all its children. For the rest, just return our own psize.
    102  *
    103  * e.g.
    104  *			psize	rsize
    105  * root			-	-
    106  *	mirror/raidz	-	-
    107  *	    disk1	20g	20g
    108  *	    disk2 	40g	20g
    109  *	disk3 		80g	80g
    110  */
    111 uint64_t
    112 vdev_get_rsize(vdev_t *vd)
    113 {
    114 	vdev_t *pvd, *cvd;
    115 	uint64_t c, rsize;
    116 
    117 	pvd = vd->vdev_parent;
    118 
    119 	/*
    120 	 * If our parent is NULL or the root, just return our own psize.
    121 	 */
    122 	if (pvd == NULL || pvd->vdev_parent == NULL)
    123 		return (vd->vdev_psize);
    124 
    125 	rsize = 0;
    126 
    127 	for (c = 0; c < pvd->vdev_children; c++) {
    128 		cvd = pvd->vdev_child[c];
    129 		rsize = MIN(rsize - 1, cvd->vdev_psize - 1) + 1;
    130 	}
    131 
    132 	return (rsize);
    133 }
    134 
    135 vdev_t *
    136 vdev_lookup_top(spa_t *spa, uint64_t vdev)
    137 {
    138 	vdev_t *rvd = spa->spa_root_vdev;
    139 
    140 	ASSERT(spa_config_held(spa, RW_READER) ||
    141 	    curthread == spa->spa_scrub_thread);
    142 
    143 	if (vdev < rvd->vdev_children)
    144 		return (rvd->vdev_child[vdev]);
    145 
    146 	return (NULL);
    147 }
    148 
    149 vdev_t *
    150 vdev_lookup_by_guid(vdev_t *vd, uint64_t guid)
    151 {
    152 	int c;
    153 	vdev_t *mvd;
    154 
    155 	if (vd->vdev_guid == guid)
    156 		return (vd);
    157 
    158 	for (c = 0; c < vd->vdev_children; c++)
    159 		if ((mvd = vdev_lookup_by_guid(vd->vdev_child[c], guid)) !=
    160 		    NULL)
    161 			return (mvd);
    162 
    163 	return (NULL);
    164 }
    165 
    166 void
    167 vdev_add_child(vdev_t *pvd, vdev_t *cvd)
    168 {
    169 	size_t oldsize, newsize;
    170 	uint64_t id = cvd->vdev_id;
    171 	vdev_t **newchild;
    172 
    173 	ASSERT(spa_config_held(cvd->vdev_spa, RW_WRITER));
    174 	ASSERT(cvd->vdev_parent == NULL);
    175 
    176 	cvd->vdev_parent = pvd;
    177 
    178 	if (pvd == NULL)
    179 		return;
    180 
    181 	ASSERT(id >= pvd->vdev_children || pvd->vdev_child[id] == NULL);
    182 
    183 	oldsize = pvd->vdev_children * sizeof (vdev_t *);
    184 	pvd->vdev_children = MAX(pvd->vdev_children, id + 1);
    185 	newsize = pvd->vdev_children * sizeof (vdev_t *);
    186 
    187 	newchild = kmem_zalloc(newsize, KM_SLEEP);
    188 	if (pvd->vdev_child != NULL) {
    189 		bcopy(pvd->vdev_child, newchild, oldsize);
    190 		kmem_free(pvd->vdev_child, oldsize);
    191 	}
    192 
    193 	pvd->vdev_child = newchild;
    194 	pvd->vdev_child[id] = cvd;
    195 
    196 	cvd->vdev_top = (pvd->vdev_top ? pvd->vdev_top: cvd);
    197 	ASSERT(cvd->vdev_top->vdev_parent->vdev_parent == NULL);
    198 
    199 	/*
    200 	 * Walk up all ancestors to update guid sum.
    201 	 */
    202 	for (; pvd != NULL; pvd = pvd->vdev_parent)
    203 		pvd->vdev_guid_sum += cvd->vdev_guid_sum;
    204 
    205 	if (cvd->vdev_ops->vdev_op_leaf)
    206 		cvd->vdev_spa->spa_scrub_maxinflight += zfs_scrub_limit;
    207 }
    208 
    209 void
    210 vdev_remove_child(vdev_t *pvd, vdev_t *cvd)
    211 {
    212 	int c;
    213 	uint_t id = cvd->vdev_id;
    214 
    215 	ASSERT(cvd->vdev_parent == pvd);
    216 
    217 	if (pvd == NULL)
    218 		return;
    219 
    220 	ASSERT(id < pvd->vdev_children);
    221 	ASSERT(pvd->vdev_child[id] == cvd);
    222 
    223 	pvd->vdev_child[id] = NULL;
    224 	cvd->vdev_parent = NULL;
    225 
    226 	for (c = 0; c < pvd->vdev_children; c++)
    227 		if (pvd->vdev_child[c])
    228 			break;
    229 
    230 	if (c == pvd->vdev_children) {
    231 		kmem_free(pvd->vdev_child, c * sizeof (vdev_t *));
    232 		pvd->vdev_child = NULL;
    233 		pvd->vdev_children = 0;
    234 	}
    235 
    236 	/*
    237 	 * Walk up all ancestors to update guid sum.
    238 	 */
    239 	for (; pvd != NULL; pvd = pvd->vdev_parent)
    240 		pvd->vdev_guid_sum -= cvd->vdev_guid_sum;
    241 
    242 	if (cvd->vdev_ops->vdev_op_leaf)
    243 		cvd->vdev_spa->spa_scrub_maxinflight -= zfs_scrub_limit;
    244 }
    245 
    246 /*
    247  * Remove any holes in the child array.
    248  */
    249 void
    250 vdev_compact_children(vdev_t *pvd)
    251 {
    252 	vdev_t **newchild, *cvd;
    253 	int oldc = pvd->vdev_children;
    254 	int newc, c;
    255 
    256 	ASSERT(spa_config_held(pvd->vdev_spa, RW_WRITER));
    257 
    258 	for (c = newc = 0; c < oldc; c++)
    259 		if (pvd->vdev_child[c])
    260 			newc++;
    261 
    262 	newchild = kmem_alloc(newc * sizeof (vdev_t *), KM_SLEEP);
    263 
    264 	for (c = newc = 0; c < oldc; c++) {
    265 		if ((cvd = pvd->vdev_child[c]) != NULL) {
    266 			newchild[newc] = cvd;
    267 			cvd->vdev_id = newc++;
    268 		}
    269 	}
    270 
    271 	kmem_free(pvd->vdev_child, oldc * sizeof (vdev_t *));
    272 	pvd->vdev_child = newchild;
    273 	pvd->vdev_children = newc;
    274 }
    275 
    276 /*
    277  * Allocate and minimally initialize a vdev_t.
    278  */
    279 static vdev_t *
    280 vdev_alloc_common(spa_t *spa, uint_t id, uint64_t guid, vdev_ops_t *ops)
    281 {
    282 	vdev_t *vd;
    283 
    284 	vd = kmem_zalloc(sizeof (vdev_t), KM_SLEEP);
    285 
    286 	if (spa->spa_root_vdev == NULL) {
    287 		ASSERT(ops == &vdev_root_ops);
    288 		spa->spa_root_vdev = vd;
    289 	}
    290 
    291 	if (guid == 0) {
    292 		if (spa->spa_root_vdev == vd) {
    293 			/*
    294 			 * The root vdev's guid will also be the pool guid,
    295 			 * which must be unique among all pools.
    296 			 */
    297 			while (guid == 0 || spa_guid_exists(guid, 0))
    298 				guid = spa_get_random(-1ULL);
    299 		} else {
    300 			/*
    301 			 * Any other vdev's guid must be unique within the pool.
    302 			 */
    303 			while (guid == 0 ||
    304 			    spa_guid_exists(spa_guid(spa), guid))
    305 				guid = spa_get_random(-1ULL);
    306 		}
    307 		ASSERT(!spa_guid_exists(spa_guid(spa), guid));
    308 	}
    309 
    310 	vd->vdev_spa = spa;
    311 	vd->vdev_id = id;
    312 	vd->vdev_guid = guid;
    313 	vd->vdev_guid_sum = guid;
    314 	vd->vdev_ops = ops;
    315 	vd->vdev_state = VDEV_STATE_CLOSED;
    316 
    317 	mutex_init(&vd->vdev_dtl_lock, NULL, MUTEX_DEFAULT, NULL);
    318 	mutex_init(&vd->vdev_stat_lock, NULL, MUTEX_DEFAULT, NULL);
    319 	space_map_create(&vd->vdev_dtl_map, 0, -1ULL, 0, &vd->vdev_dtl_lock);
    320 	space_map_create(&vd->vdev_dtl_scrub, 0, -1ULL, 0, &vd->vdev_dtl_lock);
    321 	txg_list_create(&vd->vdev_ms_list,
    322 	    offsetof(struct metaslab, ms_txg_node));
    323 	txg_list_create(&vd->vdev_dtl_list,
    324 	    offsetof(struct vdev, vdev_dtl_node));
    325 	vd->vdev_stat.vs_timestamp = gethrtime();
    326 	vdev_queue_init(vd);
    327 	vdev_cache_init(vd);
    328 
    329 	return (vd);
    330 }
    331 
    332 /*
    333  * Allocate a new vdev.  The 'alloctype' is used to control whether we are
    334  * creating a new vdev or loading an existing one - the behavior is slightly
    335  * different for each case.
    336  */
    337 int
    338 vdev_alloc(spa_t *spa, vdev_t **vdp, nvlist_t *nv, vdev_t *parent, uint_t id,
    339     int alloctype)
    340 {
    341 	vdev_ops_t *ops;
    342 	char *type;
    343 	uint64_t guid = 0, islog, nparity;
    344 	vdev_t *vd;
    345 
    346 	ASSERT(spa_config_held(spa, RW_WRITER));
    347 
    348 	if (nvlist_lookup_string(nv, ZPOOL_CONFIG_TYPE, &type) != 0)
    349 		return (EINVAL);
    350 
    351 	if ((ops = vdev_getops(type)) == NULL)
    352 		return (EINVAL);
    353 
    354 	/*
    355 	 * If this is a load, get the vdev guid from the nvlist.
    356 	 * Otherwise, vdev_alloc_common() will generate one for us.
    357 	 */
    358 	if (alloctype == VDEV_ALLOC_LOAD) {
    359 		uint64_t label_id;
    360 
    361 		if (nvlist_lookup_uint64(nv, ZPOOL_CONFIG_ID, &label_id) ||
    362 		    label_id != id)
    363 			return (EINVAL);
    364 
    365 		if (nvlist_lookup_uint64(nv, ZPOOL_CONFIG_GUID, &guid) != 0)
    366 			return (EINVAL);
    367 	} else if (alloctype == VDEV_ALLOC_SPARE) {
    368 		if (nvlist_lookup_uint64(nv, ZPOOL_CONFIG_GUID, &guid) != 0)
    369 			return (EINVAL);
    370 	} else if (alloctype == VDEV_ALLOC_L2CACHE) {
    371 		if (nvlist_lookup_uint64(nv, ZPOOL_CONFIG_GUID, &guid) != 0)
    372 			return (EINVAL);
    373 	}
    374 
    375 	/*
    376 	 * The first allocated vdev must be of type 'root'.
    377 	 */
    378 	if (ops != &vdev_root_ops && spa->spa_root_vdev == NULL)
    379 		return (EINVAL);
    380 
    381 	/*
    382 	 * Determine whether we're a log vdev.
    383 	 */
    384 	islog = 0;
    385 	(void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_IS_LOG, &islog);
    386 	if (islog && spa_version(spa) < SPA_VERSION_SLOGS)
    387 		return (ENOTSUP);
    388 
    389 	/*
    390 	 * Set the nparity property for RAID-Z vdevs.
    391 	 */
    392 	nparity = -1ULL;
    393 	if (ops == &vdev_raidz_ops) {
    394 		if (nvlist_lookup_uint64(nv, ZPOOL_CONFIG_NPARITY,
    395 		    &nparity) == 0) {
    396 			/*
    397 			 * Currently, we can only support 2 parity devices.
    398 			 */
    399 			if (nparity == 0 || nparity > 2)
    400 				return (EINVAL);
    401 			/*
    402 			 * Older versions can only support 1 parity device.
    403 			 */
    404 			if (nparity == 2 &&
    405 			    spa_version(spa) < SPA_VERSION_RAID6)
    406 				return (ENOTSUP);
    407 		} else {
    408 			/*
    409 			 * We require the parity to be specified for SPAs that
    410 			 * support multiple parity levels.
    411 			 */
    412 			if (spa_version(spa) >= SPA_VERSION_RAID6)
    413 				return (EINVAL);
    414 			/*
    415 			 * Otherwise, we default to 1 parity device for RAID-Z.
    416 			 */
    417 			nparity = 1;
    418 		}
    419 	} else {
    420 		nparity = 0;
    421 	}
    422 	ASSERT(nparity != -1ULL);
    423 
    424 	vd = vdev_alloc_common(spa, id, guid, ops);
    425 
    426 	vd->vdev_islog = islog;
    427 	vd->vdev_nparity = nparity;
    428 
    429 	if (nvlist_lookup_string(nv, ZPOOL_CONFIG_PATH, &vd->vdev_path) == 0)
    430 		vd->vdev_path = spa_strdup(vd->vdev_path);
    431 	if (nvlist_lookup_string(nv, ZPOOL_CONFIG_DEVID, &vd->vdev_devid) == 0)
    432 		vd->vdev_devid = spa_strdup(vd->vdev_devid);
    433 	if (nvlist_lookup_string(nv, ZPOOL_CONFIG_PHYS_PATH,
    434 	    &vd->vdev_physpath) == 0)
    435 		vd->vdev_physpath = spa_strdup(vd->vdev_physpath);
    436 
    437 	/*
    438 	 * Set the whole_disk property.  If it's not specified, leave the value
    439 	 * as -1.
    440 	 */
    441 	if (nvlist_lookup_uint64(nv, ZPOOL_CONFIG_WHOLE_DISK,
    442 	    &vd->vdev_wholedisk) != 0)
    443 		vd->vdev_wholedisk = -1ULL;
    444 
    445 	/*
    446 	 * Look for the 'not present' flag.  This will only be set if the device
    447 	 * was not present at the time of import.
    448 	 */
    449 	if (!spa->spa_import_faulted)
    450 		(void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_NOT_PRESENT,
    451 		    &vd->vdev_not_present);
    452 
    453 	/*
    454 	 * Get the alignment requirement.
    455 	 */
    456 	(void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_ASHIFT, &vd->vdev_ashift);
    457 
    458 	/*
    459 	 * If we're a top-level vdev, try to load the allocation parameters.
    460 	 */
    461 	if (parent && !parent->vdev_parent && alloctype == VDEV_ALLOC_LOAD) {
    462 		(void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_METASLAB_ARRAY,
    463 		    &vd->vdev_ms_array);
    464 		(void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_METASLAB_SHIFT,
    465 		    &vd->vdev_ms_shift);
    466 		(void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_ASIZE,
    467 		    &vd->vdev_asize);
    468 	}
    469 
    470 	/*
    471 	 * If we're a leaf vdev, try to load the DTL object and other state.
    472 	 */
    473 	if (vd->vdev_ops->vdev_op_leaf &&
    474 	    (alloctype == VDEV_ALLOC_LOAD || alloctype == VDEV_ALLOC_L2CACHE)) {
    475 		if (alloctype == VDEV_ALLOC_LOAD) {
    476 			(void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_DTL,
    477 			    &vd->vdev_dtl.smo_object);
    478 			(void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_UNSPARE,
    479 			    &vd->vdev_unspare);
    480 		}
    481 		(void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_OFFLINE,
    482 		    &vd->vdev_offline);
    483 
    484 		/*
    485 		 * When importing a pool, we want to ignore the persistent fault
    486 		 * state, as the diagnosis made on another system may not be
    487 		 * valid in the current context.
    488 		 */
    489 		if (spa->spa_load_state == SPA_LOAD_OPEN) {
    490 			(void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_FAULTED,
    491 			    &vd->vdev_faulted);
    492 			(void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_DEGRADED,
    493 			    &vd->vdev_degraded);
    494 			(void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_REMOVED,
    495 			    &vd->vdev_removed);
    496 		}
    497 	}
    498 
    499 	/*
    500 	 * Add ourselves to the parent's list of children.
    501 	 */
    502 	vdev_add_child(parent, vd);
    503 
    504 	*vdp = vd;
    505 
    506 	return (0);
    507 }
    508 
    509 void
    510 vdev_free(vdev_t *vd)
    511 {
    512 	int c;
    513 	spa_t *spa = vd->vdev_spa;
    514 
    515 	/*
    516 	 * vdev_free() implies closing the vdev first.  This is simpler than
    517 	 * trying to ensure complicated semantics for all callers.
    518 	 */
    519 	vdev_close(vd);
    520 
    521 
    522 	ASSERT(!list_link_active(&vd->vdev_dirty_node));
    523 
    524 	/*
    525 	 * Free all children.
    526 	 */
    527 	for (c = 0; c < vd->vdev_children; c++)
    528 		vdev_free(vd->vdev_child[c]);
    529 
    530 	ASSERT(vd->vdev_child == NULL);
    531 	ASSERT(vd->vdev_guid_sum == vd->vdev_guid);
    532 
    533 	/*
    534 	 * Discard allocation state.
    535 	 */
    536 	if (vd == vd->vdev_top)
    537 		vdev_metaslab_fini(vd);
    538 
    539 	ASSERT3U(vd->vdev_stat.vs_space, ==, 0);
    540 	ASSERT3U(vd->vdev_stat.vs_dspace, ==, 0);
    541 	ASSERT3U(vd->vdev_stat.vs_alloc, ==, 0);
    542 
    543 	/*
    544 	 * Remove this vdev from its parent's child list.
    545 	 */
    546 	vdev_remove_child(vd->vdev_parent, vd);
    547 
    548 	ASSERT(vd->vdev_parent == NULL);
    549 
    550 	/*
    551 	 * Clean up vdev structure.
    552 	 */
    553 	vdev_queue_fini(vd);
    554 	vdev_cache_fini(vd);
    555 
    556 	if (vd->vdev_path)
    557 		spa_strfree(vd->vdev_path);
    558 	if (vd->vdev_devid)
    559 		spa_strfree(vd->vdev_devid);
    560 	if (vd->vdev_physpath)
    561 		spa_strfree(vd->vdev_physpath);
    562 
    563 	if (vd->vdev_isspare)
    564 		spa_spare_remove(vd);
    565 	if (vd->vdev_isl2cache)
    566 		spa_l2cache_remove(vd);
    567 
    568 	txg_list_destroy(&vd->vdev_ms_list);
    569 	txg_list_destroy(&vd->vdev_dtl_list);
    570 	mutex_enter(&vd->vdev_dtl_lock);
    571 	space_map_unload(&vd->vdev_dtl_map);
    572 	space_map_destroy(&vd->vdev_dtl_map);
    573 	space_map_vacate(&vd->vdev_dtl_scrub, NULL, NULL);
    574 	space_map_destroy(&vd->vdev_dtl_scrub);
    575 	mutex_exit(&vd->vdev_dtl_lock);
    576 	mutex_destroy(&vd->vdev_dtl_lock);
    577 	mutex_destroy(&vd->vdev_stat_lock);
    578 
    579 	if (vd == spa->spa_root_vdev)
    580 		spa->spa_root_vdev = NULL;
    581 
    582 	kmem_free(vd, sizeof (vdev_t));
    583 }
    584 
    585 /*
    586  * Transfer top-level vdev state from svd to tvd.
    587  */
    588 static void
    589 vdev_top_transfer(vdev_t *svd, vdev_t *tvd)
    590 {
    591 	spa_t *spa = svd->vdev_spa;
    592 	metaslab_t *msp;
    593 	vdev_t *vd;
    594 	int t;
    595 
    596 	ASSERT(tvd == tvd->vdev_top);
    597 
    598 	tvd->vdev_ms_array = svd->vdev_ms_array;
    599 	tvd->vdev_ms_shift = svd->vdev_ms_shift;
    600 	tvd->vdev_ms_count = svd->vdev_ms_count;
    601 
    602 	svd->vdev_ms_array = 0;
    603 	svd->vdev_ms_shift = 0;
    604 	svd->vdev_ms_count = 0;
    605 
    606 	tvd->vdev_mg = svd->vdev_mg;
    607 	tvd->vdev_ms = svd->vdev_ms;
    608 
    609 	svd->vdev_mg = NULL;
    610 	svd->vdev_ms = NULL;
    611 
    612 	if (tvd->vdev_mg != NULL)
    613 		tvd->vdev_mg->mg_vd = tvd;
    614 
    615 	tvd->vdev_stat.vs_alloc = svd->vdev_stat.vs_alloc;
    616 	tvd->vdev_stat.vs_space = svd->vdev_stat.vs_space;
    617 	tvd->vdev_stat.vs_dspace = svd->vdev_stat.vs_dspace;
    618 
    619 	svd->vdev_stat.vs_alloc = 0;
    620 	svd->vdev_stat.vs_space = 0;
    621 	svd->vdev_stat.vs_dspace = 0;
    622 
    623 	for (t = 0; t < TXG_SIZE; t++) {
    624 		while ((msp = txg_list_remove(&svd->vdev_ms_list, t)) != NULL)
    625 			(void) txg_list_add(&tvd->vdev_ms_list, msp, t);
    626 		while ((vd = txg_list_remove(&svd->vdev_dtl_list, t)) != NULL)
    627 			(void) txg_list_add(&tvd->vdev_dtl_list, vd, t);
    628 		if (txg_list_remove_this(&spa->spa_vdev_txg_list, svd, t))
    629 			(void) txg_list_add(&spa->spa_vdev_txg_list, tvd, t);
    630 	}
    631 
    632 	if (list_link_active(&svd->vdev_dirty_node)) {
    633 		vdev_config_clean(svd);
    634 		vdev_config_dirty(tvd);
    635 	}
    636 
    637 	tvd->vdev_deflate_ratio = svd->vdev_deflate_ratio;
    638 	svd->vdev_deflate_ratio = 0;
    639 
    640 	tvd->vdev_islog = svd->vdev_islog;
    641 	svd->vdev_islog = 0;
    642 }
    643 
    644 static void
    645 vdev_top_update(vdev_t *tvd, vdev_t *vd)
    646 {
    647 	int c;
    648 
    649 	if (vd == NULL)
    650 		return;
    651 
    652 	vd->vdev_top = tvd;
    653 
    654 	for (c = 0; c < vd->vdev_children; c++)
    655 		vdev_top_update(tvd, vd->vdev_child[c]);
    656 }
    657 
    658 /*
    659  * Add a mirror/replacing vdev above an existing vdev.
    660  */
    661 vdev_t *
    662 vdev_add_parent(vdev_t *cvd, vdev_ops_t *ops)
    663 {
    664 	spa_t *spa = cvd->vdev_spa;
    665 	vdev_t *pvd = cvd->vdev_parent;
    666 	vdev_t *mvd;
    667 
    668 	ASSERT(spa_config_held(spa, RW_WRITER));
    669 
    670 	mvd = vdev_alloc_common(spa, cvd->vdev_id, 0, ops);
    671 
    672 	mvd->vdev_asize = cvd->vdev_asize;
    673 	mvd->vdev_ashift = cvd->vdev_ashift;
    674 	mvd->vdev_state = cvd->vdev_state;
    675 
    676 	vdev_remove_child(pvd, cvd);
    677 	vdev_add_child(pvd, mvd);
    678 	cvd->vdev_id = mvd->vdev_children;
    679 	vdev_add_child(mvd, cvd);
    680 	vdev_top_update(cvd->vdev_top, cvd->vdev_top);
    681 
    682 	if (mvd == mvd->vdev_top)
    683 		vdev_top_transfer(cvd, mvd);
    684 
    685 	return (mvd);
    686 }
    687 
    688 /*
    689  * Remove a 1-way mirror/replacing vdev from the tree.
    690  */
    691 void
    692 vdev_remove_parent(vdev_t *cvd)
    693 {
    694 	vdev_t *mvd = cvd->vdev_parent;
    695 	vdev_t *pvd = mvd->vdev_parent;
    696 
    697 	ASSERT(spa_config_held(cvd->vdev_spa, RW_WRITER));
    698 
    699 	ASSERT(mvd->vdev_children == 1);
    700 	ASSERT(mvd->vdev_ops == &vdev_mirror_ops ||
    701 	    mvd->vdev_ops == &vdev_replacing_ops ||
    702 	    mvd->vdev_ops == &vdev_spare_ops);
    703 	cvd->vdev_ashift = mvd->vdev_ashift;
    704 
    705 	vdev_remove_child(mvd, cvd);
    706 	vdev_remove_child(pvd, mvd);
    707 	cvd->vdev_id = mvd->vdev_id;
    708 	vdev_add_child(pvd, cvd);
    709 	/*
    710 	 * If we created a new toplevel vdev, then we need to change the child's
    711 	 * vdev GUID to match the old toplevel vdev.  Otherwise, we could have
    712 	 * detached an offline device, and when we go to import the pool we'll
    713 	 * think we have two toplevel vdevs, instead of a different version of
    714 	 * the same toplevel vdev.
    715 	 */
    716 	if (cvd->vdev_top == cvd) {
    717 		pvd->vdev_guid_sum -= cvd->vdev_guid;
    718 		cvd->vdev_guid_sum -= cvd->vdev_guid;
    719 		cvd->vdev_guid = mvd->vdev_guid;
    720 		cvd->vdev_guid_sum += mvd->vdev_guid;
    721 		pvd->vdev_guid_sum += cvd->vdev_guid;
    722 	}
    723 	vdev_top_update(cvd->vdev_top, cvd->vdev_top);
    724 
    725 	if (cvd == cvd->vdev_top)
    726 		vdev_top_transfer(mvd, cvd);
    727 
    728 	ASSERT(mvd->vdev_children == 0);
    729 	vdev_free(mvd);
    730 }
    731 
    732 int
    733 vdev_metaslab_init(vdev_t *vd, uint64_t txg)
    734 {
    735 	spa_t *spa = vd->vdev_spa;
    736 	objset_t *mos = spa->spa_meta_objset;
    737 	metaslab_class_t *mc;
    738 	uint64_t m;
    739 	uint64_t oldc = vd->vdev_ms_count;
    740 	uint64_t newc = vd->vdev_asize >> vd->vdev_ms_shift;
    741 	metaslab_t **mspp;
    742 	int error;
    743 
    744 	if (vd->vdev_ms_shift == 0)	/* not being allocated from yet */
    745 		return (0);
    746 
    747 	dprintf("%s oldc %llu newc %llu\n", vdev_description(vd), oldc, newc);
    748 
    749 	ASSERT(oldc <= newc);
    750 
    751 	if (vd->vdev_islog)
    752 		mc = spa->spa_log_class;
    753 	else
    754 		mc = spa->spa_normal_class;
    755 
    756 	if (vd->vdev_mg == NULL)
    757 		vd->vdev_mg = metaslab_group_create(mc, vd);
    758 
    759 	mspp = kmem_zalloc(newc * sizeof (*mspp), KM_SLEEP);
    760 
    761 	if (oldc != 0) {
    762 		bcopy(vd->vdev_ms, mspp, oldc * sizeof (*mspp));
    763 		kmem_free(vd->vdev_ms, oldc * sizeof (*mspp));
    764 	}
    765 
    766 	vd->vdev_ms = mspp;
    767 	vd->vdev_ms_count = newc;
    768 
    769 	for (m = oldc; m < newc; m++) {
    770 		space_map_obj_t smo = { 0, 0, 0 };
    771 		if (txg == 0) {
    772 			uint64_t object = 0;
    773 			error = dmu_read(mos, vd->vdev_ms_array,
    774 			    m * sizeof (uint64_t), sizeof (uint64_t), &object);
    775 			if (error)
    776 				return (error);
    777 			if (object != 0) {
    778 				dmu_buf_t *db;
    779 				error = dmu_bonus_hold(mos, object, FTAG, &db);
    780 				if (error)
    781 					return (error);
    782 				ASSERT3U(db->db_size, >=, sizeof (smo));
    783 				bcopy(db->db_data, &smo, sizeof (smo));
    784 				ASSERT3U(smo.smo_object, ==, object);
    785 				dmu_buf_rele(db, FTAG);
    786 			}
    787 		}
    788 		vd->vdev_ms[m] = metaslab_init(vd->vdev_mg, &smo,
    789 		    m << vd->vdev_ms_shift, 1ULL << vd->vdev_ms_shift, txg);
    790 	}
    791 
    792 	return (0);
    793 }
    794 
    795 void
    796 vdev_metaslab_fini(vdev_t *vd)
    797 {
    798 	uint64_t m;
    799 	uint64_t count = vd->vdev_ms_count;
    800 
    801 	if (vd->vdev_ms != NULL) {
    802 		for (m = 0; m < count; m++)
    803 			if (vd->vdev_ms[m] != NULL)
    804 				metaslab_fini(vd->vdev_ms[m]);
    805 		kmem_free(vd->vdev_ms, count * sizeof (metaslab_t *));
    806 		vd->vdev_ms = NULL;
    807 	}
    808 }
    809 
    810 int
    811 vdev_probe(vdev_t *vd)
    812 {
    813 	if (vd == NULL)
    814 		return (EINVAL);
    815 
    816 	/*
    817 	 * Right now we only support status checks on the leaf vdevs.
    818 	 */
    819 	if (vd->vdev_ops->vdev_op_leaf)
    820 		return (vd->vdev_ops->vdev_op_probe(vd));
    821 
    822 	return (0);
    823 }
    824 
    825 /*
    826  * Prepare a virtual device for access.
    827  */
    828 int
    829 vdev_open(vdev_t *vd)
    830 {
    831 	int error;
    832 	int c;
    833 	uint64_t osize = 0;
    834 	uint64_t asize, psize;
    835 	uint64_t ashift = 0;
    836 
    837 	ASSERT(vd->vdev_state == VDEV_STATE_CLOSED ||
    838 	    vd->vdev_state == VDEV_STATE_CANT_OPEN ||
    839 	    vd->vdev_state == VDEV_STATE_OFFLINE);
    840 
    841 	if (vd->vdev_fault_mode == VDEV_FAULT_COUNT)
    842 		vd->vdev_fault_arg >>= 1;
    843 	else
    844 		vd->vdev_fault_mode = VDEV_FAULT_NONE;
    845 
    846 	vd->vdev_stat.vs_aux = VDEV_AUX_NONE;
    847 
    848 	if (!vd->vdev_removed && vd->vdev_faulted) {
    849 		ASSERT(vd->vdev_children == 0);
    850 		vdev_set_state(vd, B_TRUE, VDEV_STATE_FAULTED,
    851 		    VDEV_AUX_ERR_EXCEEDED);
    852 		return (ENXIO);
    853 	} else if (vd->vdev_offline) {
    854 		ASSERT(vd->vdev_children == 0);
    855 		vdev_set_state(vd, B_TRUE, VDEV_STATE_OFFLINE, VDEV_AUX_NONE);
    856 		return (ENXIO);
    857 	}
    858 
    859 	error = vd->vdev_ops->vdev_op_open(vd, &osize, &ashift);
    860 
    861 	if (zio_injection_enabled && error == 0)
    862 		error = zio_handle_device_injection(vd, ENXIO);
    863 
    864 	if (error) {
    865 		if (vd->vdev_removed &&
    866 		    vd->vdev_stat.vs_aux != VDEV_AUX_OPEN_FAILED)
    867 			vd->vdev_removed = B_FALSE;
    868 
    869 		vdev_set_state(vd, B_TRUE, VDEV_STATE_CANT_OPEN,
    870 		    vd->vdev_stat.vs_aux);
    871 		return (error);
    872 	}
    873 
    874 	vd->vdev_removed = B_FALSE;
    875 
    876 	if (vd->vdev_degraded) {
    877 		ASSERT(vd->vdev_children == 0);
    878 		vdev_set_state(vd, B_TRUE, VDEV_STATE_DEGRADED,
    879 		    VDEV_AUX_ERR_EXCEEDED);
    880 	} else {
    881 		vd->vdev_state = VDEV_STATE_HEALTHY;
    882 	}
    883 
    884 	for (c = 0; c < vd->vdev_children; c++)
    885 		if (vd->vdev_child[c]->vdev_state != VDEV_STATE_HEALTHY) {
    886 			vdev_set_state(vd, B_TRUE, VDEV_STATE_DEGRADED,
    887 			    VDEV_AUX_NONE);
    888 			break;
    889 		}
    890 
    891 	osize = P2ALIGN(osize, (uint64_t)sizeof (vdev_label_t));
    892 
    893 	if (vd->vdev_children == 0) {
    894 		if (osize < SPA_MINDEVSIZE) {
    895 			vdev_set_state(vd, B_TRUE, VDEV_STATE_CANT_OPEN,
    896 			    VDEV_AUX_TOO_SMALL);
    897 			return (EOVERFLOW);
    898 		}
    899 		psize = osize;
    900 		asize = osize - (VDEV_LABEL_START_SIZE + VDEV_LABEL_END_SIZE);
    901 	} else {
    902 		if (vd->vdev_parent != NULL && osize < SPA_MINDEVSIZE -
    903 		    (VDEV_LABEL_START_SIZE + VDEV_LABEL_END_SIZE)) {
    904 			vdev_set_state(vd, B_TRUE, VDEV_STATE_CANT_OPEN,
    905 			    VDEV_AUX_TOO_SMALL);
    906 			return (EOVERFLOW);
    907 		}
    908 		psize = 0;
    909 		asize = osize;
    910 	}
    911 
    912 	vd->vdev_psize = psize;
    913 
    914 	if (vd->vdev_asize == 0) {
    915 		/*
    916 		 * This is the first-ever open, so use the computed values.
    917 		 * For testing purposes, a higher ashift can be requested.
    918 		 */
    919 		vd->vdev_asize = asize;
    920 		vd->vdev_ashift = MAX(ashift, vd->vdev_ashift);
    921 	} else {
    922 		/*
    923 		 * Make sure the alignment requirement hasn't increased.
    924 		 */
    925 		if (ashift > vd->vdev_top->vdev_ashift) {
    926 			vdev_set_state(vd, B_TRUE, VDEV_STATE_CANT_OPEN,
    927 			    VDEV_AUX_BAD_LABEL);
    928 			return (EINVAL);
    929 		}
    930 
    931 		/*
    932 		 * Make sure the device hasn't shrunk.
    933 		 */
    934 		if (asize < vd->vdev_asize) {
    935 			vdev_set_state(vd, B_TRUE, VDEV_STATE_CANT_OPEN,
    936 			    VDEV_AUX_BAD_LABEL);
    937 			return (EINVAL);
    938 		}
    939 
    940 		/*
    941 		 * If all children are healthy and the asize has increased,
    942 		 * then we've experienced dynamic LUN growth.
    943 		 */
    944 		if (vd->vdev_state == VDEV_STATE_HEALTHY &&
    945 		    asize > vd->vdev_asize) {
    946 			vd->vdev_asize = asize;
    947 		}
    948 	}
    949 
    950 	/*
    951 	 * Ensure we can issue some IO before declaring the
    952 	 * vdev open for business.
    953 	 */
    954 	error = vdev_probe(vd);
    955 	if (error) {
    956 		vdev_set_state(vd, B_TRUE, VDEV_STATE_CANT_OPEN,
    957 		    VDEV_AUX_OPEN_FAILED);
    958 		return (error);
    959 	}
    960 
    961 	/*
    962 	 * If this is a top-level vdev, compute the raidz-deflation
    963 	 * ratio.  Note, we hard-code in 128k (1<<17) because it is the
    964 	 * current "typical" blocksize.  Even if SPA_MAXBLOCKSIZE
    965 	 * changes, this algorithm must never change, or we will
    966 	 * inconsistently account for existing bp's.
    967 	 */
    968 	if (vd->vdev_top == vd) {
    969 		vd->vdev_deflate_ratio = (1<<17) /
    970 		    (vdev_psize_to_asize(vd, 1<<17) >> SPA_MINBLOCKSHIFT);
    971 	}
    972 
    973 	return (0);
    974 }
    975 
    976 /*
    977  * Called once the vdevs are all opened, this routine validates the label
    978  * contents.  This needs to be done before vdev_load() so that we don't
    979  * inadvertently do repair I/Os to the wrong device.
    980  *
    981  * This function will only return failure if one of the vdevs indicates that it
    982  * has since been destroyed or exported.  This is only possible if
    983  * /etc/zfs/zpool.cache was readonly at the time.  Otherwise, the vdev state
    984  * will be updated but the function will return 0.
    985  */
    986 int
    987 vdev_validate(vdev_t *vd)
    988 {
    989 	spa_t *spa = vd->vdev_spa;
    990 	int c;
    991 	nvlist_t *label;
    992 	uint64_t guid;
    993 	uint64_t state;
    994 
    995 	for (c = 0; c < vd->vdev_children; c++)
    996 		if (vdev_validate(vd->vdev_child[c]) != 0)
    997 			return (EBADF);
    998 
    999 	/*
   1000 	 * If the device has already failed, or was marked offline, don't do
   1001 	 * any further validation.  Otherwise, label I/O will fail and we will
   1002 	 * overwrite the previous state.
   1003 	 */
   1004 	if (vd->vdev_ops->vdev_op_leaf && !vdev_is_dead(vd)) {
   1005 
   1006 		if ((label = vdev_label_read_config(vd)) == NULL) {
   1007 			vdev_set_state(vd, B_TRUE, VDEV_STATE_CANT_OPEN,
   1008 			    VDEV_AUX_BAD_LABEL);
   1009 			return (0);
   1010 		}
   1011 
   1012 		if (nvlist_lookup_uint64(label, ZPOOL_CONFIG_POOL_GUID,
   1013 		    &guid) != 0 || guid != spa_guid(spa)) {
   1014 			vdev_set_state(vd, B_FALSE, VDEV_STATE_CANT_OPEN,
   1015 			    VDEV_AUX_CORRUPT_DATA);
   1016 			nvlist_free(label);
   1017 			return (0);
   1018 		}
   1019 
   1020 		if (nvlist_lookup_uint64(label, ZPOOL_CONFIG_GUID,
   1021 		    &guid) != 0 || guid != vd->vdev_guid) {
   1022 			vdev_set_state(vd, B_FALSE, VDEV_STATE_CANT_OPEN,
   1023 			    VDEV_AUX_CORRUPT_DATA);
   1024 			nvlist_free(label);
   1025 			return (0);
   1026 		}
   1027 
   1028 		if (nvlist_lookup_uint64(label, ZPOOL_CONFIG_POOL_STATE,
   1029 		    &state) != 0) {
   1030 			vdev_set_state(vd, B_FALSE, VDEV_STATE_CANT_OPEN,
   1031 			    VDEV_AUX_CORRUPT_DATA);
   1032