xref: /freebsd/stand/libsa/zfs/zfsimpl.c (revision 06c3fb2749bda94cb5201f81ffdb8fa6c3161b2e)
1 /*-
2  * Copyright (c) 2007 Doug Rabson
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  */
26 
27 #include <sys/cdefs.h>
28 /*
29  *	Stand-alone ZFS file reader.
30  */
31 
32 #include <stdbool.h>
33 #include <sys/endian.h>
34 #include <sys/stat.h>
35 #include <sys/stdint.h>
36 #include <sys/list.h>
37 #include <sys/zfs_bootenv.h>
38 #include <machine/_inttypes.h>
39 
40 #include "zfsimpl.h"
41 #include "zfssubr.c"
42 
43 #ifdef HAS_ZSTD_ZFS
44 extern int zstd_init(void);
45 #endif
46 
47 struct zfsmount {
48 	char			*path;
49 	const spa_t		*spa;
50 	objset_phys_t		objset;
51 	uint64_t		rootobj;
52 	STAILQ_ENTRY(zfsmount)	next;
53 };
54 
55 typedef STAILQ_HEAD(zfs_mnt_list, zfsmount) zfs_mnt_list_t;
56 static zfs_mnt_list_t zfsmount = STAILQ_HEAD_INITIALIZER(zfsmount);
57 
58 /*
59  * The indirect_child_t represents the vdev that we will read from, when we
60  * need to read all copies of the data (e.g. for scrub or reconstruction).
61  * For plain (non-mirror) top-level vdevs (i.e. is_vdev is not a mirror),
62  * ic_vdev is the same as is_vdev.  However, for mirror top-level vdevs,
63  * ic_vdev is a child of the mirror.
64  */
65 typedef struct indirect_child {
66 	void *ic_data;
67 	vdev_t *ic_vdev;
68 } indirect_child_t;
69 
70 /*
71  * The indirect_split_t represents one mapped segment of an i/o to the
72  * indirect vdev. For non-split (contiguously-mapped) blocks, there will be
73  * only one indirect_split_t, with is_split_offset==0 and is_size==io_size.
74  * For split blocks, there will be several of these.
75  */
76 typedef struct indirect_split {
77 	list_node_t is_node; /* link on iv_splits */
78 
79 	/*
80 	 * is_split_offset is the offset into the i/o.
81 	 * This is the sum of the previous splits' is_size's.
82 	 */
83 	uint64_t is_split_offset;
84 
85 	vdev_t *is_vdev; /* top-level vdev */
86 	uint64_t is_target_offset; /* offset on is_vdev */
87 	uint64_t is_size;
88 	int is_children; /* number of entries in is_child[] */
89 
90 	/*
91 	 * is_good_child is the child that we are currently using to
92 	 * attempt reconstruction.
93 	 */
94 	int is_good_child;
95 
96 	indirect_child_t is_child[1]; /* variable-length */
97 } indirect_split_t;
98 
99 /*
100  * The indirect_vsd_t is associated with each i/o to the indirect vdev.
101  * It is the "Vdev-Specific Data" in the zio_t's io_vsd.
102  */
103 typedef struct indirect_vsd {
104 	boolean_t iv_split_block;
105 	boolean_t iv_reconstruct;
106 
107 	list_t iv_splits; /* list of indirect_split_t's */
108 } indirect_vsd_t;
109 
110 /*
111  * List of all vdevs, chained through v_alllink.
112  */
113 static vdev_list_t zfs_vdevs;
114 
115 /*
116  * List of supported read-incompatible ZFS features.  Do not add here features
117  * marked as ZFEATURE_FLAG_READONLY_COMPAT, they are irrelevant for read-only!
118  */
119 static const char *features_for_read[] = {
120 	"com.datto:bookmark_v2",
121 	"com.datto:encryption",
122 	"com.delphix:bookmark_written",
123 	"com.delphix:device_removal",
124 	"com.delphix:embedded_data",
125 	"com.delphix:extensible_dataset",
126 	"com.delphix:head_errlog",
127 	"com.delphix:hole_birth",
128 	"com.joyent:multi_vdev_crash_dump",
129 	"com.klarasystems:vdev_zaps_v2",
130 	"org.freebsd:zstd_compress",
131 	"org.illumos:lz4_compress",
132 	"org.illumos:sha512",
133 	"org.illumos:skein",
134 	"org.open-zfs:large_blocks",
135 	"org.openzfs:blake3",
136 	"org.zfsonlinux:large_dnode",
137 	NULL
138 };
139 
140 /*
141  * List of all pools, chained through spa_link.
142  */
143 static spa_list_t zfs_pools;
144 
145 static const dnode_phys_t *dnode_cache_obj;
146 static uint64_t dnode_cache_bn;
147 static char *dnode_cache_buf;
148 
149 static int zio_read(const spa_t *spa, const blkptr_t *bp, void *buf);
150 static int zfs_get_root(const spa_t *spa, uint64_t *objid);
151 static int zfs_rlookup(const spa_t *spa, uint64_t objnum, char *result);
152 static int zap_lookup(const spa_t *spa, const dnode_phys_t *dnode,
153     const char *name, uint64_t integer_size, uint64_t num_integers,
154     void *value);
155 static int objset_get_dnode(const spa_t *, const objset_phys_t *, uint64_t,
156     dnode_phys_t *);
157 static int dnode_read(const spa_t *, const dnode_phys_t *, off_t, void *,
158     size_t);
159 static int vdev_indirect_read(vdev_t *, const blkptr_t *, void *, off_t,
160     size_t);
161 static int vdev_mirror_read(vdev_t *, const blkptr_t *, void *, off_t, size_t);
162 vdev_indirect_mapping_t *vdev_indirect_mapping_open(spa_t *, objset_phys_t *,
163     uint64_t);
164 vdev_indirect_mapping_entry_phys_t *
165     vdev_indirect_mapping_duplicate_adjacent_entries(vdev_t *, uint64_t,
166     uint64_t, uint64_t *);
167 
168 static void
169 zfs_init(void)
170 {
171 	STAILQ_INIT(&zfs_vdevs);
172 	STAILQ_INIT(&zfs_pools);
173 
174 	dnode_cache_buf = malloc(SPA_MAXBLOCKSIZE);
175 
176 	zfs_init_crc();
177 #ifdef HAS_ZSTD_ZFS
178 	zstd_init();
179 #endif
180 }
181 
182 static int
183 nvlist_check_features_for_read(nvlist_t *nvl)
184 {
185 	nvlist_t *features = NULL;
186 	nvs_data_t *data;
187 	nvp_header_t *nvp;
188 	nv_string_t *nvp_name;
189 	int rc;
190 
191 	rc = nvlist_find(nvl, ZPOOL_CONFIG_FEATURES_FOR_READ,
192 	    DATA_TYPE_NVLIST, NULL, &features, NULL);
193 	switch (rc) {
194 	case 0:
195 		break;		/* Continue with checks */
196 
197 	case ENOENT:
198 		return (0);	/* All features are disabled */
199 
200 	default:
201 		return (rc);	/* Error while reading nvlist */
202 	}
203 
204 	data = (nvs_data_t *)features->nv_data;
205 	nvp = &data->nvl_pair;	/* first pair in nvlist */
206 
207 	while (nvp->encoded_size != 0 && nvp->decoded_size != 0) {
208 		int i, found;
209 
210 		nvp_name = (nv_string_t *)((uintptr_t)nvp + sizeof(*nvp));
211 		found = 0;
212 
213 		for (i = 0; features_for_read[i] != NULL; i++) {
214 			if (memcmp(nvp_name->nv_data, features_for_read[i],
215 			    nvp_name->nv_size) == 0) {
216 				found = 1;
217 				break;
218 			}
219 		}
220 
221 		if (!found) {
222 			printf("ZFS: unsupported feature: %.*s\n",
223 			    nvp_name->nv_size, nvp_name->nv_data);
224 			rc = EIO;
225 		}
226 		nvp = (nvp_header_t *)((uint8_t *)nvp + nvp->encoded_size);
227 	}
228 	nvlist_destroy(features);
229 
230 	return (rc);
231 }
232 
233 static int
234 vdev_read_phys(vdev_t *vdev, const blkptr_t *bp, void *buf,
235     off_t offset, size_t size)
236 {
237 	size_t psize;
238 	int rc;
239 
240 	if (vdev->v_phys_read == NULL)
241 		return (ENOTSUP);
242 
243 	if (bp) {
244 		psize = BP_GET_PSIZE(bp);
245 	} else {
246 		psize = size;
247 	}
248 
249 	rc = vdev->v_phys_read(vdev, vdev->v_priv, offset, buf, psize);
250 	if (rc == 0) {
251 		if (bp != NULL)
252 			rc = zio_checksum_verify(vdev->v_spa, bp, buf);
253 	}
254 
255 	return (rc);
256 }
257 
258 static int
259 vdev_write_phys(vdev_t *vdev, void *buf, off_t offset, size_t size)
260 {
261 	if (vdev->v_phys_write == NULL)
262 		return (ENOTSUP);
263 
264 	return (vdev->v_phys_write(vdev, offset, buf, size));
265 }
266 
267 typedef struct remap_segment {
268 	vdev_t *rs_vd;
269 	uint64_t rs_offset;
270 	uint64_t rs_asize;
271 	uint64_t rs_split_offset;
272 	list_node_t rs_node;
273 } remap_segment_t;
274 
275 static remap_segment_t *
276 rs_alloc(vdev_t *vd, uint64_t offset, uint64_t asize, uint64_t split_offset)
277 {
278 	remap_segment_t *rs = malloc(sizeof (remap_segment_t));
279 
280 	if (rs != NULL) {
281 		rs->rs_vd = vd;
282 		rs->rs_offset = offset;
283 		rs->rs_asize = asize;
284 		rs->rs_split_offset = split_offset;
285 	}
286 
287 	return (rs);
288 }
289 
290 vdev_indirect_mapping_t *
291 vdev_indirect_mapping_open(spa_t *spa, objset_phys_t *os,
292     uint64_t mapping_object)
293 {
294 	vdev_indirect_mapping_t *vim;
295 	vdev_indirect_mapping_phys_t *vim_phys;
296 	int rc;
297 
298 	vim = calloc(1, sizeof (*vim));
299 	if (vim == NULL)
300 		return (NULL);
301 
302 	vim->vim_dn = calloc(1, sizeof (*vim->vim_dn));
303 	if (vim->vim_dn == NULL) {
304 		free(vim);
305 		return (NULL);
306 	}
307 
308 	rc = objset_get_dnode(spa, os, mapping_object, vim->vim_dn);
309 	if (rc != 0) {
310 		free(vim->vim_dn);
311 		free(vim);
312 		return (NULL);
313 	}
314 
315 	vim->vim_spa = spa;
316 	vim->vim_phys = malloc(sizeof (*vim->vim_phys));
317 	if (vim->vim_phys == NULL) {
318 		free(vim->vim_dn);
319 		free(vim);
320 		return (NULL);
321 	}
322 
323 	vim_phys = (vdev_indirect_mapping_phys_t *)DN_BONUS(vim->vim_dn);
324 	*vim->vim_phys = *vim_phys;
325 
326 	vim->vim_objset = os;
327 	vim->vim_object = mapping_object;
328 	vim->vim_entries = NULL;
329 
330 	vim->vim_havecounts =
331 	    (vim->vim_dn->dn_bonuslen > VDEV_INDIRECT_MAPPING_SIZE_V0);
332 
333 	return (vim);
334 }
335 
336 /*
337  * Compare an offset with an indirect mapping entry; there are three
338  * possible scenarios:
339  *
340  *     1. The offset is "less than" the mapping entry; meaning the
341  *        offset is less than the source offset of the mapping entry. In
342  *        this case, there is no overlap between the offset and the
343  *        mapping entry and -1 will be returned.
344  *
345  *     2. The offset is "greater than" the mapping entry; meaning the
346  *        offset is greater than the mapping entry's source offset plus
347  *        the entry's size. In this case, there is no overlap between
348  *        the offset and the mapping entry and 1 will be returned.
349  *
350  *        NOTE: If the offset is actually equal to the entry's offset
351  *        plus size, this is considered to be "greater" than the entry,
352  *        and this case applies (i.e. 1 will be returned). Thus, the
353  *        entry's "range" can be considered to be inclusive at its
354  *        start, but exclusive at its end: e.g. [src, src + size).
355  *
356  *     3. The last case to consider is if the offset actually falls
357  *        within the mapping entry's range. If this is the case, the
358  *        offset is considered to be "equal to" the mapping entry and
359  *        0 will be returned.
360  *
361  *        NOTE: If the offset is equal to the entry's source offset,
362  *        this case applies and 0 will be returned. If the offset is
363  *        equal to the entry's source plus its size, this case does
364  *        *not* apply (see "NOTE" above for scenario 2), and 1 will be
365  *        returned.
366  */
367 static int
368 dva_mapping_overlap_compare(const void *v_key, const void *v_array_elem)
369 {
370 	const uint64_t *key = v_key;
371 	const vdev_indirect_mapping_entry_phys_t *array_elem =
372 	    v_array_elem;
373 	uint64_t src_offset = DVA_MAPPING_GET_SRC_OFFSET(array_elem);
374 
375 	if (*key < src_offset) {
376 		return (-1);
377 	} else if (*key < src_offset + DVA_GET_ASIZE(&array_elem->vimep_dst)) {
378 		return (0);
379 	} else {
380 		return (1);
381 	}
382 }
383 
384 /*
385  * Return array entry.
386  */
387 static vdev_indirect_mapping_entry_phys_t *
388 vdev_indirect_mapping_entry(vdev_indirect_mapping_t *vim, uint64_t index)
389 {
390 	uint64_t size;
391 	off_t offset = 0;
392 	int rc;
393 
394 	if (vim->vim_phys->vimp_num_entries == 0)
395 		return (NULL);
396 
397 	if (vim->vim_entries == NULL) {
398 		uint64_t bsize;
399 
400 		bsize = vim->vim_dn->dn_datablkszsec << SPA_MINBLOCKSHIFT;
401 		size = vim->vim_phys->vimp_num_entries *
402 		    sizeof (*vim->vim_entries);
403 		if (size > bsize) {
404 			size = bsize / sizeof (*vim->vim_entries);
405 			size *= sizeof (*vim->vim_entries);
406 		}
407 		vim->vim_entries = malloc(size);
408 		if (vim->vim_entries == NULL)
409 			return (NULL);
410 		vim->vim_num_entries = size / sizeof (*vim->vim_entries);
411 		offset = index * sizeof (*vim->vim_entries);
412 	}
413 
414 	/* We have data in vim_entries */
415 	if (offset == 0) {
416 		if (index >= vim->vim_entry_offset &&
417 		    index <= vim->vim_entry_offset + vim->vim_num_entries) {
418 			index -= vim->vim_entry_offset;
419 			return (&vim->vim_entries[index]);
420 		}
421 		offset = index * sizeof (*vim->vim_entries);
422 	}
423 
424 	vim->vim_entry_offset = index;
425 	size = vim->vim_num_entries * sizeof (*vim->vim_entries);
426 	rc = dnode_read(vim->vim_spa, vim->vim_dn, offset, vim->vim_entries,
427 	    size);
428 	if (rc != 0) {
429 		/* Read error, invalidate vim_entries. */
430 		free(vim->vim_entries);
431 		vim->vim_entries = NULL;
432 		return (NULL);
433 	}
434 	index -= vim->vim_entry_offset;
435 	return (&vim->vim_entries[index]);
436 }
437 
438 /*
439  * Returns the mapping entry for the given offset.
440  *
441  * It's possible that the given offset will not be in the mapping table
442  * (i.e. no mapping entries contain this offset), in which case, the
443  * return value depends on the "next_if_missing" parameter.
444  *
445  * If the offset is not found in the table and "next_if_missing" is
446  * B_FALSE, then NULL will always be returned. The behavior is intended
447  * to allow consumers to get the entry corresponding to the offset
448  * parameter, iff the offset overlaps with an entry in the table.
449  *
450  * If the offset is not found in the table and "next_if_missing" is
451  * B_TRUE, then the entry nearest to the given offset will be returned,
452  * such that the entry's source offset is greater than the offset
453  * passed in (i.e. the "next" mapping entry in the table is returned, if
454  * the offset is missing from the table). If there are no entries whose
455  * source offset is greater than the passed in offset, NULL is returned.
456  */
457 static vdev_indirect_mapping_entry_phys_t *
458 vdev_indirect_mapping_entry_for_offset(vdev_indirect_mapping_t *vim,
459     uint64_t offset)
460 {
461 	ASSERT(vim->vim_phys->vimp_num_entries > 0);
462 
463 	vdev_indirect_mapping_entry_phys_t *entry;
464 
465 	uint64_t last = vim->vim_phys->vimp_num_entries - 1;
466 	uint64_t base = 0;
467 
468 	/*
469 	 * We don't define these inside of the while loop because we use
470 	 * their value in the case that offset isn't in the mapping.
471 	 */
472 	uint64_t mid;
473 	int result;
474 
475 	while (last >= base) {
476 		mid = base + ((last - base) >> 1);
477 
478 		entry = vdev_indirect_mapping_entry(vim, mid);
479 		if (entry == NULL)
480 			break;
481 		result = dva_mapping_overlap_compare(&offset, entry);
482 
483 		if (result == 0) {
484 			break;
485 		} else if (result < 0) {
486 			last = mid - 1;
487 		} else {
488 			base = mid + 1;
489 		}
490 	}
491 	return (entry);
492 }
493 
494 /*
495  * Given an indirect vdev and an extent on that vdev, it duplicates the
496  * physical entries of the indirect mapping that correspond to the extent
497  * to a new array and returns a pointer to it. In addition, copied_entries
498  * is populated with the number of mapping entries that were duplicated.
499  *
500  * Finally, since we are doing an allocation, it is up to the caller to
501  * free the array allocated in this function.
502  */
503 vdev_indirect_mapping_entry_phys_t *
504 vdev_indirect_mapping_duplicate_adjacent_entries(vdev_t *vd, uint64_t offset,
505     uint64_t asize, uint64_t *copied_entries)
506 {
507 	vdev_indirect_mapping_entry_phys_t *duplicate_mappings = NULL;
508 	vdev_indirect_mapping_t *vim = vd->v_mapping;
509 	uint64_t entries = 0;
510 
511 	vdev_indirect_mapping_entry_phys_t *first_mapping =
512 	    vdev_indirect_mapping_entry_for_offset(vim, offset);
513 	ASSERT3P(first_mapping, !=, NULL);
514 
515 	vdev_indirect_mapping_entry_phys_t *m = first_mapping;
516 	while (asize > 0) {
517 		uint64_t size = DVA_GET_ASIZE(&m->vimep_dst);
518 		uint64_t inner_offset = offset - DVA_MAPPING_GET_SRC_OFFSET(m);
519 		uint64_t inner_size = MIN(asize, size - inner_offset);
520 
521 		offset += inner_size;
522 		asize -= inner_size;
523 		entries++;
524 		m++;
525 	}
526 
527 	size_t copy_length = entries * sizeof (*first_mapping);
528 	duplicate_mappings = malloc(copy_length);
529 	if (duplicate_mappings != NULL)
530 		bcopy(first_mapping, duplicate_mappings, copy_length);
531 	else
532 		entries = 0;
533 
534 	*copied_entries = entries;
535 
536 	return (duplicate_mappings);
537 }
538 
539 static vdev_t *
540 vdev_lookup_top(spa_t *spa, uint64_t vdev)
541 {
542 	vdev_t *rvd;
543 	vdev_list_t *vlist;
544 
545 	vlist = &spa->spa_root_vdev->v_children;
546 	STAILQ_FOREACH(rvd, vlist, v_childlink)
547 		if (rvd->v_id == vdev)
548 			break;
549 
550 	return (rvd);
551 }
552 
553 /*
554  * This is a callback for vdev_indirect_remap() which allocates an
555  * indirect_split_t for each split segment and adds it to iv_splits.
556  */
557 static void
558 vdev_indirect_gather_splits(uint64_t split_offset, vdev_t *vd, uint64_t offset,
559     uint64_t size, void *arg)
560 {
561 	int n = 1;
562 	zio_t *zio = arg;
563 	indirect_vsd_t *iv = zio->io_vsd;
564 
565 	if (vd->v_read == vdev_indirect_read)
566 		return;
567 
568 	if (vd->v_read == vdev_mirror_read)
569 		n = vd->v_nchildren;
570 
571 	indirect_split_t *is =
572 	    malloc(offsetof(indirect_split_t, is_child[n]));
573 	if (is == NULL) {
574 		zio->io_error = ENOMEM;
575 		return;
576 	}
577 	bzero(is, offsetof(indirect_split_t, is_child[n]));
578 
579 	is->is_children = n;
580 	is->is_size = size;
581 	is->is_split_offset = split_offset;
582 	is->is_target_offset = offset;
583 	is->is_vdev = vd;
584 
585 	/*
586 	 * Note that we only consider multiple copies of the data for
587 	 * *mirror* vdevs.  We don't for "replacing" or "spare" vdevs, even
588 	 * though they use the same ops as mirror, because there's only one
589 	 * "good" copy under the replacing/spare.
590 	 */
591 	if (vd->v_read == vdev_mirror_read) {
592 		int i = 0;
593 		vdev_t *kid;
594 
595 		STAILQ_FOREACH(kid, &vd->v_children, v_childlink) {
596 			is->is_child[i++].ic_vdev = kid;
597 		}
598 	} else {
599 		is->is_child[0].ic_vdev = vd;
600 	}
601 
602 	list_insert_tail(&iv->iv_splits, is);
603 }
604 
605 static void
606 vdev_indirect_remap(vdev_t *vd, uint64_t offset, uint64_t asize, void *arg)
607 {
608 	list_t stack;
609 	spa_t *spa = vd->v_spa;
610 	zio_t *zio = arg;
611 	remap_segment_t *rs;
612 
613 	list_create(&stack, sizeof (remap_segment_t),
614 	    offsetof(remap_segment_t, rs_node));
615 
616 	rs = rs_alloc(vd, offset, asize, 0);
617 	if (rs == NULL) {
618 		printf("vdev_indirect_remap: out of memory.\n");
619 		zio->io_error = ENOMEM;
620 	}
621 	for (; rs != NULL; rs = list_remove_head(&stack)) {
622 		vdev_t *v = rs->rs_vd;
623 		uint64_t num_entries = 0;
624 		/* vdev_indirect_mapping_t *vim = v->v_mapping; */
625 		vdev_indirect_mapping_entry_phys_t *mapping =
626 		    vdev_indirect_mapping_duplicate_adjacent_entries(v,
627 		    rs->rs_offset, rs->rs_asize, &num_entries);
628 
629 		if (num_entries == 0)
630 			zio->io_error = ENOMEM;
631 
632 		for (uint64_t i = 0; i < num_entries; i++) {
633 			vdev_indirect_mapping_entry_phys_t *m = &mapping[i];
634 			uint64_t size = DVA_GET_ASIZE(&m->vimep_dst);
635 			uint64_t dst_offset = DVA_GET_OFFSET(&m->vimep_dst);
636 			uint64_t dst_vdev = DVA_GET_VDEV(&m->vimep_dst);
637 			uint64_t inner_offset = rs->rs_offset -
638 			    DVA_MAPPING_GET_SRC_OFFSET(m);
639 			uint64_t inner_size =
640 			    MIN(rs->rs_asize, size - inner_offset);
641 			vdev_t *dst_v = vdev_lookup_top(spa, dst_vdev);
642 
643 			if (dst_v->v_read == vdev_indirect_read) {
644 				remap_segment_t *o;
645 
646 				o = rs_alloc(dst_v, dst_offset + inner_offset,
647 				    inner_size, rs->rs_split_offset);
648 				if (o == NULL) {
649 					printf("vdev_indirect_remap: "
650 					    "out of memory.\n");
651 					zio->io_error = ENOMEM;
652 					break;
653 				}
654 
655 				list_insert_head(&stack, o);
656 			}
657 			vdev_indirect_gather_splits(rs->rs_split_offset, dst_v,
658 			    dst_offset + inner_offset,
659 			    inner_size, arg);
660 
661 			/*
662 			 * vdev_indirect_gather_splits can have memory
663 			 * allocation error, we can not recover from it.
664 			 */
665 			if (zio->io_error != 0)
666 				break;
667 			rs->rs_offset += inner_size;
668 			rs->rs_asize -= inner_size;
669 			rs->rs_split_offset += inner_size;
670 		}
671 
672 		free(mapping);
673 		free(rs);
674 		if (zio->io_error != 0)
675 			break;
676 	}
677 
678 	list_destroy(&stack);
679 }
680 
681 static void
682 vdev_indirect_map_free(zio_t *zio)
683 {
684 	indirect_vsd_t *iv = zio->io_vsd;
685 	indirect_split_t *is;
686 
687 	while ((is = list_head(&iv->iv_splits)) != NULL) {
688 		for (int c = 0; c < is->is_children; c++) {
689 			indirect_child_t *ic = &is->is_child[c];
690 			free(ic->ic_data);
691 		}
692 		list_remove(&iv->iv_splits, is);
693 		free(is);
694 	}
695 	free(iv);
696 }
697 
698 static int
699 vdev_indirect_read(vdev_t *vdev, const blkptr_t *bp, void *buf,
700     off_t offset, size_t bytes)
701 {
702 	zio_t zio;
703 	spa_t *spa = vdev->v_spa;
704 	indirect_vsd_t *iv;
705 	indirect_split_t *first;
706 	int rc = EIO;
707 
708 	iv = calloc(1, sizeof(*iv));
709 	if (iv == NULL)
710 		return (ENOMEM);
711 
712 	list_create(&iv->iv_splits,
713 	    sizeof (indirect_split_t), offsetof(indirect_split_t, is_node));
714 
715 	bzero(&zio, sizeof(zio));
716 	zio.io_spa = spa;
717 	zio.io_bp = (blkptr_t *)bp;
718 	zio.io_data = buf;
719 	zio.io_size = bytes;
720 	zio.io_offset = offset;
721 	zio.io_vd = vdev;
722 	zio.io_vsd = iv;
723 
724 	if (vdev->v_mapping == NULL) {
725 		vdev_indirect_config_t *vic;
726 
727 		vic = &vdev->vdev_indirect_config;
728 		vdev->v_mapping = vdev_indirect_mapping_open(spa,
729 		    spa->spa_mos, vic->vic_mapping_object);
730 	}
731 
732 	vdev_indirect_remap(vdev, offset, bytes, &zio);
733 	if (zio.io_error != 0)
734 		return (zio.io_error);
735 
736 	first = list_head(&iv->iv_splits);
737 	if (first->is_size == zio.io_size) {
738 		/*
739 		 * This is not a split block; we are pointing to the entire
740 		 * data, which will checksum the same as the original data.
741 		 * Pass the BP down so that the child i/o can verify the
742 		 * checksum, and try a different location if available
743 		 * (e.g. on a mirror).
744 		 *
745 		 * While this special case could be handled the same as the
746 		 * general (split block) case, doing it this way ensures
747 		 * that the vast majority of blocks on indirect vdevs
748 		 * (which are not split) are handled identically to blocks
749 		 * on non-indirect vdevs.  This allows us to be less strict
750 		 * about performance in the general (but rare) case.
751 		 */
752 		rc = first->is_vdev->v_read(first->is_vdev, zio.io_bp,
753 		    zio.io_data, first->is_target_offset, bytes);
754 	} else {
755 		iv->iv_split_block = B_TRUE;
756 		/*
757 		 * Read one copy of each split segment, from the
758 		 * top-level vdev.  Since we don't know the
759 		 * checksum of each split individually, the child
760 		 * zio can't ensure that we get the right data.
761 		 * E.g. if it's a mirror, it will just read from a
762 		 * random (healthy) leaf vdev.  We have to verify
763 		 * the checksum in vdev_indirect_io_done().
764 		 */
765 		for (indirect_split_t *is = list_head(&iv->iv_splits);
766 		    is != NULL; is = list_next(&iv->iv_splits, is)) {
767 			char *ptr = zio.io_data;
768 
769 			rc = is->is_vdev->v_read(is->is_vdev, zio.io_bp,
770 			    ptr + is->is_split_offset, is->is_target_offset,
771 			    is->is_size);
772 		}
773 		if (zio_checksum_verify(spa, zio.io_bp, zio.io_data))
774 			rc = ECKSUM;
775 		else
776 			rc = 0;
777 	}
778 
779 	vdev_indirect_map_free(&zio);
780 	if (rc == 0)
781 		rc = zio.io_error;
782 
783 	return (rc);
784 }
785 
786 static int
787 vdev_disk_read(vdev_t *vdev, const blkptr_t *bp, void *buf,
788     off_t offset, size_t bytes)
789 {
790 
791 	return (vdev_read_phys(vdev, bp, buf,
792 	    offset + VDEV_LABEL_START_SIZE, bytes));
793 }
794 
795 static int
796 vdev_missing_read(vdev_t *vdev __unused, const blkptr_t *bp __unused,
797     void *buf __unused, off_t offset __unused, size_t bytes __unused)
798 {
799 
800 	return (ENOTSUP);
801 }
802 
803 static int
804 vdev_mirror_read(vdev_t *vdev, const blkptr_t *bp, void *buf,
805     off_t offset, size_t bytes)
806 {
807 	vdev_t *kid;
808 	int rc;
809 
810 	rc = EIO;
811 	STAILQ_FOREACH(kid, &vdev->v_children, v_childlink) {
812 		if (kid->v_state != VDEV_STATE_HEALTHY)
813 			continue;
814 		rc = kid->v_read(kid, bp, buf, offset, bytes);
815 		if (!rc)
816 			return (0);
817 	}
818 
819 	return (rc);
820 }
821 
822 static int
823 vdev_replacing_read(vdev_t *vdev, const blkptr_t *bp, void *buf,
824     off_t offset, size_t bytes)
825 {
826 	vdev_t *kid;
827 
828 	/*
829 	 * Here we should have two kids:
830 	 * First one which is the one we are replacing and we can trust
831 	 * only this one to have valid data, but it might not be present.
832 	 * Second one is that one we are replacing with. It is most likely
833 	 * healthy, but we can't trust it has needed data, so we won't use it.
834 	 */
835 	kid = STAILQ_FIRST(&vdev->v_children);
836 	if (kid == NULL)
837 		return (EIO);
838 	if (kid->v_state != VDEV_STATE_HEALTHY)
839 		return (EIO);
840 	return (kid->v_read(kid, bp, buf, offset, bytes));
841 }
842 
843 static vdev_t *
844 vdev_find(uint64_t guid)
845 {
846 	vdev_t *vdev;
847 
848 	STAILQ_FOREACH(vdev, &zfs_vdevs, v_alllink)
849 		if (vdev->v_guid == guid)
850 			return (vdev);
851 
852 	return (0);
853 }
854 
855 static vdev_t *
856 vdev_create(uint64_t guid, vdev_read_t *_read)
857 {
858 	vdev_t *vdev;
859 	vdev_indirect_config_t *vic;
860 
861 	vdev = calloc(1, sizeof(vdev_t));
862 	if (vdev != NULL) {
863 		STAILQ_INIT(&vdev->v_children);
864 		vdev->v_guid = guid;
865 		vdev->v_read = _read;
866 
867 		/*
868 		 * root vdev has no read function, we use this fact to
869 		 * skip setting up data we do not need for root vdev.
870 		 * We only point root vdev from spa.
871 		 */
872 		if (_read != NULL) {
873 			vic = &vdev->vdev_indirect_config;
874 			vic->vic_prev_indirect_vdev = UINT64_MAX;
875 			STAILQ_INSERT_TAIL(&zfs_vdevs, vdev, v_alllink);
876 		}
877 	}
878 
879 	return (vdev);
880 }
881 
882 static void
883 vdev_set_initial_state(vdev_t *vdev, const nvlist_t *nvlist)
884 {
885 	uint64_t is_offline, is_faulted, is_degraded, is_removed, isnt_present;
886 	uint64_t is_log;
887 
888 	is_offline = is_removed = is_faulted = is_degraded = isnt_present = 0;
889 	is_log = 0;
890 	(void) nvlist_find(nvlist, ZPOOL_CONFIG_OFFLINE, DATA_TYPE_UINT64, NULL,
891 	    &is_offline, NULL);
892 	(void) nvlist_find(nvlist, ZPOOL_CONFIG_REMOVED, DATA_TYPE_UINT64, NULL,
893 	    &is_removed, NULL);
894 	(void) nvlist_find(nvlist, ZPOOL_CONFIG_FAULTED, DATA_TYPE_UINT64, NULL,
895 	    &is_faulted, NULL);
896 	(void) nvlist_find(nvlist, ZPOOL_CONFIG_DEGRADED, DATA_TYPE_UINT64,
897 	    NULL, &is_degraded, NULL);
898 	(void) nvlist_find(nvlist, ZPOOL_CONFIG_NOT_PRESENT, DATA_TYPE_UINT64,
899 	    NULL, &isnt_present, NULL);
900 	(void) nvlist_find(nvlist, ZPOOL_CONFIG_IS_LOG, DATA_TYPE_UINT64, NULL,
901 	    &is_log, NULL);
902 
903 	if (is_offline != 0)
904 		vdev->v_state = VDEV_STATE_OFFLINE;
905 	else if (is_removed != 0)
906 		vdev->v_state = VDEV_STATE_REMOVED;
907 	else if (is_faulted != 0)
908 		vdev->v_state = VDEV_STATE_FAULTED;
909 	else if (is_degraded != 0)
910 		vdev->v_state = VDEV_STATE_DEGRADED;
911 	else if (isnt_present != 0)
912 		vdev->v_state = VDEV_STATE_CANT_OPEN;
913 
914 	vdev->v_islog = is_log != 0;
915 }
916 
917 static int
918 vdev_init(uint64_t guid, const nvlist_t *nvlist, vdev_t **vdevp)
919 {
920 	uint64_t id, ashift, asize, nparity;
921 	const char *path;
922 	const char *type;
923 	int len, pathlen;
924 	char *name;
925 	vdev_t *vdev;
926 
927 	if (nvlist_find(nvlist, ZPOOL_CONFIG_ID, DATA_TYPE_UINT64, NULL, &id,
928 	    NULL) ||
929 	    nvlist_find(nvlist, ZPOOL_CONFIG_TYPE, DATA_TYPE_STRING, NULL,
930 	    &type, &len)) {
931 		return (ENOENT);
932 	}
933 
934 	if (memcmp(type, VDEV_TYPE_MIRROR, len) != 0 &&
935 	    memcmp(type, VDEV_TYPE_DISK, len) != 0 &&
936 #ifdef ZFS_TEST
937 	    memcmp(type, VDEV_TYPE_FILE, len) != 0 &&
938 #endif
939 	    memcmp(type, VDEV_TYPE_RAIDZ, len) != 0 &&
940 	    memcmp(type, VDEV_TYPE_INDIRECT, len) != 0 &&
941 	    memcmp(type, VDEV_TYPE_REPLACING, len) != 0 &&
942 	    memcmp(type, VDEV_TYPE_HOLE, len) != 0) {
943 		printf("ZFS: can only boot from disk, mirror, raidz1, "
944 		    "raidz2 and raidz3 vdevs, got: %.*s\n", len, type);
945 		return (EIO);
946 	}
947 
948 	if (memcmp(type, VDEV_TYPE_MIRROR, len) == 0)
949 		vdev = vdev_create(guid, vdev_mirror_read);
950 	else if (memcmp(type, VDEV_TYPE_RAIDZ, len) == 0)
951 		vdev = vdev_create(guid, vdev_raidz_read);
952 	else if (memcmp(type, VDEV_TYPE_REPLACING, len) == 0)
953 		vdev = vdev_create(guid, vdev_replacing_read);
954 	else if (memcmp(type, VDEV_TYPE_INDIRECT, len) == 0) {
955 		vdev_indirect_config_t *vic;
956 
957 		vdev = vdev_create(guid, vdev_indirect_read);
958 		if (vdev != NULL) {
959 			vdev->v_state = VDEV_STATE_HEALTHY;
960 			vic = &vdev->vdev_indirect_config;
961 
962 			nvlist_find(nvlist,
963 			    ZPOOL_CONFIG_INDIRECT_OBJECT,
964 			    DATA_TYPE_UINT64,
965 			    NULL, &vic->vic_mapping_object, NULL);
966 			nvlist_find(nvlist,
967 			    ZPOOL_CONFIG_INDIRECT_BIRTHS,
968 			    DATA_TYPE_UINT64,
969 			    NULL, &vic->vic_births_object, NULL);
970 			nvlist_find(nvlist,
971 			    ZPOOL_CONFIG_PREV_INDIRECT_VDEV,
972 			    DATA_TYPE_UINT64,
973 			    NULL, &vic->vic_prev_indirect_vdev, NULL);
974 		}
975 	} else if (memcmp(type, VDEV_TYPE_HOLE, len) == 0) {
976 		vdev = vdev_create(guid, vdev_missing_read);
977 	} else {
978 		vdev = vdev_create(guid, vdev_disk_read);
979 	}
980 
981 	if (vdev == NULL)
982 		return (ENOMEM);
983 
984 	vdev_set_initial_state(vdev, nvlist);
985 	vdev->v_id = id;
986 	if (nvlist_find(nvlist, ZPOOL_CONFIG_ASHIFT,
987 	    DATA_TYPE_UINT64, NULL, &ashift, NULL) == 0)
988 		vdev->v_ashift = ashift;
989 
990 	if (nvlist_find(nvlist, ZPOOL_CONFIG_ASIZE,
991 	    DATA_TYPE_UINT64, NULL, &asize, NULL) == 0) {
992 		vdev->v_psize = asize +
993 		    VDEV_LABEL_START_SIZE + VDEV_LABEL_END_SIZE;
994 	}
995 
996 	if (nvlist_find(nvlist, ZPOOL_CONFIG_NPARITY,
997 	    DATA_TYPE_UINT64, NULL, &nparity, NULL) == 0)
998 		vdev->v_nparity = nparity;
999 
1000 	if (nvlist_find(nvlist, ZPOOL_CONFIG_PATH,
1001 	    DATA_TYPE_STRING, NULL, &path, &pathlen) == 0) {
1002 		char prefix[] = "/dev/";
1003 
1004 		len = strlen(prefix);
1005 		if (len < pathlen && memcmp(path, prefix, len) == 0) {
1006 			path += len;
1007 			pathlen -= len;
1008 		}
1009 		name = malloc(pathlen + 1);
1010 		bcopy(path, name, pathlen);
1011 		name[pathlen] = '\0';
1012 		vdev->v_name = name;
1013 	} else {
1014 		name = NULL;
1015 		if (memcmp(type, VDEV_TYPE_RAIDZ, len) == 0) {
1016 			if (vdev->v_nparity < 1 ||
1017 			    vdev->v_nparity > 3) {
1018 				printf("ZFS: invalid raidz parity: %d\n",
1019 				    vdev->v_nparity);
1020 				return (EIO);
1021 			}
1022 			(void) asprintf(&name, "%.*s%d-%" PRIu64, len, type,
1023 			    vdev->v_nparity, id);
1024 		} else {
1025 			(void) asprintf(&name, "%.*s-%" PRIu64, len, type, id);
1026 		}
1027 		vdev->v_name = name;
1028 	}
1029 	*vdevp = vdev;
1030 	return (0);
1031 }
1032 
1033 /*
1034  * Find slot for vdev. We return either NULL to signal to use
1035  * STAILQ_INSERT_HEAD, or we return link element to be used with
1036  * STAILQ_INSERT_AFTER.
1037  */
1038 static vdev_t *
1039 vdev_find_previous(vdev_t *top_vdev, vdev_t *vdev)
1040 {
1041 	vdev_t *v, *previous;
1042 
1043 	if (STAILQ_EMPTY(&top_vdev->v_children))
1044 		return (NULL);
1045 
1046 	previous = NULL;
1047 	STAILQ_FOREACH(v, &top_vdev->v_children, v_childlink) {
1048 		if (v->v_id > vdev->v_id)
1049 			return (previous);
1050 
1051 		if (v->v_id == vdev->v_id)
1052 			return (v);
1053 
1054 		if (v->v_id < vdev->v_id)
1055 			previous = v;
1056 	}
1057 	return (previous);
1058 }
1059 
1060 static size_t
1061 vdev_child_count(vdev_t *vdev)
1062 {
1063 	vdev_t *v;
1064 	size_t count;
1065 
1066 	count = 0;
1067 	STAILQ_FOREACH(v, &vdev->v_children, v_childlink) {
1068 		count++;
1069 	}
1070 	return (count);
1071 }
1072 
1073 /*
1074  * Insert vdev into top_vdev children list. List is ordered by v_id.
1075  */
1076 static void
1077 vdev_insert(vdev_t *top_vdev, vdev_t *vdev)
1078 {
1079 	vdev_t *previous;
1080 	size_t count;
1081 
1082 	/*
1083 	 * The top level vdev can appear in random order, depending how
1084 	 * the firmware is presenting the disk devices.
1085 	 * However, we will insert vdev to create list ordered by v_id,
1086 	 * so we can use either STAILQ_INSERT_HEAD or STAILQ_INSERT_AFTER
1087 	 * as STAILQ does not have insert before.
1088 	 */
1089 	previous = vdev_find_previous(top_vdev, vdev);
1090 
1091 	if (previous == NULL) {
1092 		STAILQ_INSERT_HEAD(&top_vdev->v_children, vdev, v_childlink);
1093 	} else if (previous->v_id == vdev->v_id) {
1094 		/*
1095 		 * This vdev was configured from label config,
1096 		 * do not insert duplicate.
1097 		 */
1098 		return;
1099 	} else {
1100 		STAILQ_INSERT_AFTER(&top_vdev->v_children, previous, vdev,
1101 		    v_childlink);
1102 	}
1103 
1104 	count = vdev_child_count(top_vdev);
1105 	if (top_vdev->v_nchildren < count)
1106 		top_vdev->v_nchildren = count;
1107 }
1108 
1109 static int
1110 vdev_from_nvlist(spa_t *spa, uint64_t top_guid, const nvlist_t *nvlist)
1111 {
1112 	vdev_t *top_vdev, *vdev;
1113 	nvlist_t **kids = NULL;
1114 	int rc, nkids;
1115 
1116 	/* Get top vdev. */
1117 	top_vdev = vdev_find(top_guid);
1118 	if (top_vdev == NULL) {
1119 		rc = vdev_init(top_guid, nvlist, &top_vdev);
1120 		if (rc != 0)
1121 			return (rc);
1122 		top_vdev->v_spa = spa;
1123 		top_vdev->v_top = top_vdev;
1124 		vdev_insert(spa->spa_root_vdev, top_vdev);
1125 	}
1126 
1127 	/* Add children if there are any. */
1128 	rc = nvlist_find(nvlist, ZPOOL_CONFIG_CHILDREN, DATA_TYPE_NVLIST_ARRAY,
1129 	    &nkids, &kids, NULL);
1130 	if (rc == 0) {
1131 		for (int i = 0; i < nkids; i++) {
1132 			uint64_t guid;
1133 
1134 			rc = nvlist_find(kids[i], ZPOOL_CONFIG_GUID,
1135 			    DATA_TYPE_UINT64, NULL, &guid, NULL);
1136 			if (rc != 0)
1137 				goto done;
1138 
1139 			rc = vdev_init(guid, kids[i], &vdev);
1140 			if (rc != 0)
1141 				goto done;
1142 
1143 			vdev->v_spa = spa;
1144 			vdev->v_top = top_vdev;
1145 			vdev_insert(top_vdev, vdev);
1146 		}
1147 	} else {
1148 		/*
1149 		 * When there are no children, nvlist_find() does return
1150 		 * error, reset it because leaf devices have no children.
1151 		 */
1152 		rc = 0;
1153 	}
1154 done:
1155 	if (kids != NULL) {
1156 		for (int i = 0; i < nkids; i++)
1157 			nvlist_destroy(kids[i]);
1158 		free(kids);
1159 	}
1160 
1161 	return (rc);
1162 }
1163 
1164 static int
1165 vdev_init_from_label(spa_t *spa, const nvlist_t *nvlist)
1166 {
1167 	uint64_t pool_guid, top_guid;
1168 	nvlist_t *vdevs;
1169 	int rc;
1170 
1171 	if (nvlist_find(nvlist, ZPOOL_CONFIG_POOL_GUID, DATA_TYPE_UINT64,
1172 	    NULL, &pool_guid, NULL) ||
1173 	    nvlist_find(nvlist, ZPOOL_CONFIG_TOP_GUID, DATA_TYPE_UINT64,
1174 	    NULL, &top_guid, NULL) ||
1175 	    nvlist_find(nvlist, ZPOOL_CONFIG_VDEV_TREE, DATA_TYPE_NVLIST,
1176 	    NULL, &vdevs, NULL)) {
1177 		printf("ZFS: can't find vdev details\n");
1178 		return (ENOENT);
1179 	}
1180 
1181 	rc = vdev_from_nvlist(spa, top_guid, vdevs);
1182 	nvlist_destroy(vdevs);
1183 	return (rc);
1184 }
1185 
1186 static void
1187 vdev_set_state(vdev_t *vdev)
1188 {
1189 	vdev_t *kid;
1190 	int good_kids;
1191 	int bad_kids;
1192 
1193 	STAILQ_FOREACH(kid, &vdev->v_children, v_childlink) {
1194 		vdev_set_state(kid);
1195 	}
1196 
1197 	/*
1198 	 * A mirror or raidz is healthy if all its kids are healthy. A
1199 	 * mirror is degraded if any of its kids is healthy; a raidz
1200 	 * is degraded if at most nparity kids are offline.
1201 	 */
1202 	if (STAILQ_FIRST(&vdev->v_children)) {
1203 		good_kids = 0;
1204 		bad_kids = 0;
1205 		STAILQ_FOREACH(kid, &vdev->v_children, v_childlink) {
1206 			if (kid->v_state == VDEV_STATE_HEALTHY)
1207 				good_kids++;
1208 			else
1209 				bad_kids++;
1210 		}
1211 		if (bad_kids == 0) {
1212 			vdev->v_state = VDEV_STATE_HEALTHY;
1213 		} else {
1214 			if (vdev->v_read == vdev_mirror_read) {
1215 				if (good_kids) {
1216 					vdev->v_state = VDEV_STATE_DEGRADED;
1217 				} else {
1218 					vdev->v_state = VDEV_STATE_OFFLINE;
1219 				}
1220 			} else if (vdev->v_read == vdev_raidz_read) {
1221 				if (bad_kids > vdev->v_nparity) {
1222 					vdev->v_state = VDEV_STATE_OFFLINE;
1223 				} else {
1224 					vdev->v_state = VDEV_STATE_DEGRADED;
1225 				}
1226 			}
1227 		}
1228 	}
1229 }
1230 
1231 static int
1232 vdev_update_from_nvlist(uint64_t top_guid, const nvlist_t *nvlist)
1233 {
1234 	vdev_t *vdev;
1235 	nvlist_t **kids = NULL;
1236 	int rc, nkids;
1237 
1238 	/* Update top vdev. */
1239 	vdev = vdev_find(top_guid);
1240 	if (vdev != NULL)
1241 		vdev_set_initial_state(vdev, nvlist);
1242 
1243 	/* Update children if there are any. */
1244 	rc = nvlist_find(nvlist, ZPOOL_CONFIG_CHILDREN, DATA_TYPE_NVLIST_ARRAY,
1245 	    &nkids, &kids, NULL);
1246 	if (rc == 0) {
1247 		for (int i = 0; i < nkids; i++) {
1248 			uint64_t guid;
1249 
1250 			rc = nvlist_find(kids[i], ZPOOL_CONFIG_GUID,
1251 			    DATA_TYPE_UINT64, NULL, &guid, NULL);
1252 			if (rc != 0)
1253 				break;
1254 
1255 			vdev = vdev_find(guid);
1256 			if (vdev != NULL)
1257 				vdev_set_initial_state(vdev, kids[i]);
1258 		}
1259 	} else {
1260 		rc = 0;
1261 	}
1262 	if (kids != NULL) {
1263 		for (int i = 0; i < nkids; i++)
1264 			nvlist_destroy(kids[i]);
1265 		free(kids);
1266 	}
1267 
1268 	return (rc);
1269 }
1270 
1271 static int
1272 vdev_init_from_nvlist(spa_t *spa, const nvlist_t *nvlist)
1273 {
1274 	uint64_t pool_guid, vdev_children;
1275 	nvlist_t *vdevs = NULL, **kids = NULL;
1276 	int rc, nkids;
1277 
1278 	if (nvlist_find(nvlist, ZPOOL_CONFIG_POOL_GUID, DATA_TYPE_UINT64,
1279 	    NULL, &pool_guid, NULL) ||
1280 	    nvlist_find(nvlist, ZPOOL_CONFIG_VDEV_CHILDREN, DATA_TYPE_UINT64,
1281 	    NULL, &vdev_children, NULL) ||
1282 	    nvlist_find(nvlist, ZPOOL_CONFIG_VDEV_TREE, DATA_TYPE_NVLIST,
1283 	    NULL, &vdevs, NULL)) {
1284 		printf("ZFS: can't find vdev details\n");
1285 		return (ENOENT);
1286 	}
1287 
1288 	/* Wrong guid?! */
1289 	if (spa->spa_guid != pool_guid) {
1290 		nvlist_destroy(vdevs);
1291 		return (EINVAL);
1292 	}
1293 
1294 	spa->spa_root_vdev->v_nchildren = vdev_children;
1295 
1296 	rc = nvlist_find(vdevs, ZPOOL_CONFIG_CHILDREN, DATA_TYPE_NVLIST_ARRAY,
1297 	    &nkids, &kids, NULL);
1298 	nvlist_destroy(vdevs);
1299 
1300 	/*
1301 	 * MOS config has at least one child for root vdev.
1302 	 */
1303 	if (rc != 0)
1304 		return (rc);
1305 
1306 	for (int i = 0; i < nkids; i++) {
1307 		uint64_t guid;
1308 		vdev_t *vdev;
1309 
1310 		rc = nvlist_find(kids[i], ZPOOL_CONFIG_GUID, DATA_TYPE_UINT64,
1311 		    NULL, &guid, NULL);
1312 		if (rc != 0)
1313 			break;
1314 		vdev = vdev_find(guid);
1315 		/*
1316 		 * Top level vdev is missing, create it.
1317 		 */
1318 		if (vdev == NULL)
1319 			rc = vdev_from_nvlist(spa, guid, kids[i]);
1320 		else
1321 			rc = vdev_update_from_nvlist(guid, kids[i]);
1322 		if (rc != 0)
1323 			break;
1324 	}
1325 	if (kids != NULL) {
1326 		for (int i = 0; i < nkids; i++)
1327 			nvlist_destroy(kids[i]);
1328 		free(kids);
1329 	}
1330 
1331 	/*
1332 	 * Re-evaluate top-level vdev state.
1333 	 */
1334 	vdev_set_state(spa->spa_root_vdev);
1335 
1336 	return (rc);
1337 }
1338 
1339 static spa_t *
1340 spa_find_by_guid(uint64_t guid)
1341 {
1342 	spa_t *spa;
1343 
1344 	STAILQ_FOREACH(spa, &zfs_pools, spa_link)
1345 		if (spa->spa_guid == guid)
1346 			return (spa);
1347 
1348 	return (NULL);
1349 }
1350 
1351 static spa_t *
1352 spa_find_by_name(const char *name)
1353 {
1354 	spa_t *spa;
1355 
1356 	STAILQ_FOREACH(spa, &zfs_pools, spa_link)
1357 		if (strcmp(spa->spa_name, name) == 0)
1358 			return (spa);
1359 
1360 	return (NULL);
1361 }
1362 
1363 static spa_t *
1364 spa_create(uint64_t guid, const char *name)
1365 {
1366 	spa_t *spa;
1367 
1368 	if ((spa = calloc(1, sizeof(spa_t))) == NULL)
1369 		return (NULL);
1370 	if ((spa->spa_name = strdup(name)) == NULL) {
1371 		free(spa);
1372 		return (NULL);
1373 	}
1374 	spa->spa_uberblock = &spa->spa_uberblock_master;
1375 	spa->spa_mos = &spa->spa_mos_master;
1376 	spa->spa_guid = guid;
1377 	spa->spa_root_vdev = vdev_create(guid, NULL);
1378 	if (spa->spa_root_vdev == NULL) {
1379 		free(spa->spa_name);
1380 		free(spa);
1381 		return (NULL);
1382 	}
1383 	spa->spa_root_vdev->v_name = strdup("root");
1384 	STAILQ_INSERT_TAIL(&zfs_pools, spa, spa_link);
1385 
1386 	return (spa);
1387 }
1388 
1389 static const char *
1390 state_name(vdev_state_t state)
1391 {
1392 	static const char *names[] = {
1393 		"UNKNOWN",
1394 		"CLOSED",
1395 		"OFFLINE",
1396 		"REMOVED",
1397 		"CANT_OPEN",
1398 		"FAULTED",
1399 		"DEGRADED",
1400 		"ONLINE"
1401 	};
1402 	return (names[state]);
1403 }
1404 
1405 #ifdef BOOT2
1406 
1407 #define pager_printf printf
1408 
1409 #else
1410 
1411 static int
1412 pager_printf(const char *fmt, ...)
1413 {
1414 	char line[80];
1415 	va_list args;
1416 
1417 	va_start(args, fmt);
1418 	vsnprintf(line, sizeof(line), fmt, args);
1419 	va_end(args);
1420 	return (pager_output(line));
1421 }
1422 
1423 #endif
1424 
1425 #define	STATUS_FORMAT	"        %s %s\n"
1426 
1427 static int
1428 print_state(int indent, const char *name, vdev_state_t state)
1429 {
1430 	int i;
1431 	char buf[512];
1432 
1433 	buf[0] = 0;
1434 	for (i = 0; i < indent; i++)
1435 		strcat(buf, "  ");
1436 	strcat(buf, name);
1437 	return (pager_printf(STATUS_FORMAT, buf, state_name(state)));
1438 }
1439 
1440 static int
1441 vdev_status(vdev_t *vdev, int indent)
1442 {
1443 	vdev_t *kid;
1444 	int ret;
1445 
1446 	if (vdev->v_islog) {
1447 		(void) pager_output("        logs\n");
1448 		indent++;
1449 	}
1450 
1451 	ret = print_state(indent, vdev->v_name, vdev->v_state);
1452 	if (ret != 0)
1453 		return (ret);
1454 
1455 	STAILQ_FOREACH(kid, &vdev->v_children, v_childlink) {
1456 		ret = vdev_status(kid, indent + 1);
1457 		if (ret != 0)
1458 			return (ret);
1459 	}
1460 	return (ret);
1461 }
1462 
1463 static int
1464 spa_status(spa_t *spa)
1465 {
1466 	static char bootfs[ZFS_MAXNAMELEN];
1467 	uint64_t rootid;
1468 	vdev_list_t *vlist;
1469 	vdev_t *vdev;
1470 	int good_kids, bad_kids, degraded_kids, ret;
1471 	vdev_state_t state;
1472 
1473 	ret = pager_printf("  pool: %s\n", spa->spa_name);
1474 	if (ret != 0)
1475 		return (ret);
1476 
1477 	if (zfs_get_root(spa, &rootid) == 0 &&
1478 	    zfs_rlookup(spa, rootid, bootfs) == 0) {
1479 		if (bootfs[0] == '\0')
1480 			ret = pager_printf("bootfs: %s\n", spa->spa_name);
1481 		else
1482 			ret = pager_printf("bootfs: %s/%s\n", spa->spa_name,
1483 			    bootfs);
1484 		if (ret != 0)
1485 			return (ret);
1486 	}
1487 	ret = pager_printf("config:\n\n");
1488 	if (ret != 0)
1489 		return (ret);
1490 	ret = pager_printf(STATUS_FORMAT, "NAME", "STATE");
1491 	if (ret != 0)
1492 		return (ret);
1493 
1494 	good_kids = 0;
1495 	degraded_kids = 0;
1496 	bad_kids = 0;
1497 	vlist = &spa->spa_root_vdev->v_children;
1498 	STAILQ_FOREACH(vdev, vlist, v_childlink) {
1499 		if (vdev->v_state == VDEV_STATE_HEALTHY)
1500 			good_kids++;
1501 		else if (vdev->v_state == VDEV_STATE_DEGRADED)
1502 			degraded_kids++;
1503 		else
1504 			bad_kids++;
1505 	}
1506 
1507 	state = VDEV_STATE_CLOSED;
1508 	if (good_kids > 0 && (degraded_kids + bad_kids) == 0)
1509 		state = VDEV_STATE_HEALTHY;
1510 	else if ((good_kids + degraded_kids) > 0)
1511 		state = VDEV_STATE_DEGRADED;
1512 
1513 	ret = print_state(0, spa->spa_name, state);
1514 	if (ret != 0)
1515 		return (ret);
1516 
1517 	STAILQ_FOREACH(vdev, vlist, v_childlink) {
1518 		ret = vdev_status(vdev, 1);
1519 		if (ret != 0)
1520 			return (ret);
1521 	}
1522 	return (ret);
1523 }
1524 
1525 static int
1526 spa_all_status(void)
1527 {
1528 	spa_t *spa;
1529 	int first = 1, ret = 0;
1530 
1531 	STAILQ_FOREACH(spa, &zfs_pools, spa_link) {
1532 		if (!first) {
1533 			ret = pager_printf("\n");
1534 			if (ret != 0)
1535 				return (ret);
1536 		}
1537 		first = 0;
1538 		ret = spa_status(spa);
1539 		if (ret != 0)
1540 			return (ret);
1541 	}
1542 	return (ret);
1543 }
1544 
1545 static uint64_t
1546 vdev_label_offset(uint64_t psize, int l, uint64_t offset)
1547 {
1548 	uint64_t label_offset;
1549 
1550 	if (l < VDEV_LABELS / 2)
1551 		label_offset = 0;
1552 	else
1553 		label_offset = psize - VDEV_LABELS * sizeof (vdev_label_t);
1554 
1555 	return (offset + l * sizeof (vdev_label_t) + label_offset);
1556 }
1557 
1558 static int
1559 vdev_uberblock_compare(const uberblock_t *ub1, const uberblock_t *ub2)
1560 {
1561 	unsigned int seq1 = 0;
1562 	unsigned int seq2 = 0;
1563 	int cmp = AVL_CMP(ub1->ub_txg, ub2->ub_txg);
1564 
1565 	if (cmp != 0)
1566 		return (cmp);
1567 
1568 	cmp = AVL_CMP(ub1->ub_timestamp, ub2->ub_timestamp);
1569 	if (cmp != 0)
1570 		return (cmp);
1571 
1572 	if (MMP_VALID(ub1) && MMP_SEQ_VALID(ub1))
1573 		seq1 = MMP_SEQ(ub1);
1574 
1575 	if (MMP_VALID(ub2) && MMP_SEQ_VALID(ub2))
1576 		seq2 = MMP_SEQ(ub2);
1577 
1578 	return (AVL_CMP(seq1, seq2));
1579 }
1580 
1581 static int
1582 uberblock_verify(uberblock_t *ub)
1583 {
1584 	if (ub->ub_magic == BSWAP_64((uint64_t)UBERBLOCK_MAGIC)) {
1585 		byteswap_uint64_array(ub, sizeof (uberblock_t));
1586 	}
1587 
1588 	if (ub->ub_magic != UBERBLOCK_MAGIC ||
1589 	    !SPA_VERSION_IS_SUPPORTED(ub->ub_version))
1590 		return (EINVAL);
1591 
1592 	return (0);
1593 }
1594 
1595 static int
1596 vdev_label_read(vdev_t *vd, int l, void *buf, uint64_t offset,
1597     size_t size)
1598 {
1599 	blkptr_t bp;
1600 	off_t off;
1601 
1602 	off = vdev_label_offset(vd->v_psize, l, offset);
1603 
1604 	BP_ZERO(&bp);
1605 	BP_SET_LSIZE(&bp, size);
1606 	BP_SET_PSIZE(&bp, size);
1607 	BP_SET_CHECKSUM(&bp, ZIO_CHECKSUM_LABEL);
1608 	BP_SET_COMPRESS(&bp, ZIO_COMPRESS_OFF);
1609 	DVA_SET_OFFSET(BP_IDENTITY(&bp), off);
1610 	ZIO_SET_CHECKSUM(&bp.blk_cksum, off, 0, 0, 0);
1611 
1612 	return (vdev_read_phys(vd, &bp, buf, off, size));
1613 }
1614 
1615 /*
1616  * We do need to be sure we write to correct location.
1617  * Our vdev label does consist of 4 fields:
1618  * pad1 (8k), reserved.
1619  * bootenv (8k), checksummed, previously reserved, may contian garbage.
1620  * vdev_phys (112k), checksummed
1621  * uberblock ring (128k), checksummed.
1622  *
1623  * Since bootenv area may contain garbage, we can not reliably read it, as
1624  * we can get checksum errors.
1625  * Next best thing is vdev_phys - it is just after bootenv. It still may
1626  * be corrupted, but in such case we will miss this one write.
1627  */
1628 static int
1629 vdev_label_write_validate(vdev_t *vd, int l, uint64_t offset)
1630 {
1631 	uint64_t off, o_phys;
1632 	void *buf;
1633 	size_t size = VDEV_PHYS_SIZE;
1634 	int rc;
1635 
1636 	o_phys = offsetof(vdev_label_t, vl_vdev_phys);
1637 	off = vdev_label_offset(vd->v_psize, l, o_phys);
1638 
1639 	/* off should be 8K from bootenv */
1640 	if (vdev_label_offset(vd->v_psize, l, offset) + VDEV_PAD_SIZE != off)
1641 		return (EINVAL);
1642 
1643 	buf = malloc(size);
1644 	if (buf == NULL)
1645 		return (ENOMEM);
1646 
1647 	/* Read vdev_phys */
1648 	rc = vdev_label_read(vd, l, buf, o_phys, size);
1649 	free(buf);
1650 	return (rc);
1651 }
1652 
1653 static int
1654 vdev_label_write(vdev_t *vd, int l, vdev_boot_envblock_t *be, uint64_t offset)
1655 {
1656 	zio_checksum_info_t *ci;
1657 	zio_cksum_t cksum;
1658 	off_t off;
1659 	size_t size = VDEV_PAD_SIZE;
1660 	int rc;
1661 
1662 	if (vd->v_phys_write == NULL)
1663 		return (ENOTSUP);
1664 
1665 	off = vdev_label_offset(vd->v_psize, l, offset);
1666 
1667 	rc = vdev_label_write_validate(vd, l, offset);
1668 	if (rc != 0) {
1669 		return (rc);
1670 	}
1671 
1672 	ci = &zio_checksum_table[ZIO_CHECKSUM_LABEL];
1673 	be->vbe_zbt.zec_magic = ZEC_MAGIC;
1674 	zio_checksum_label_verifier(&be->vbe_zbt.zec_cksum, off);
1675 	ci->ci_func[0](be, size, NULL, &cksum);
1676 	be->vbe_zbt.zec_cksum = cksum;
1677 
1678 	return (vdev_write_phys(vd, be, off, size));
1679 }
1680 
1681 static int
1682 vdev_write_bootenv_impl(vdev_t *vdev, vdev_boot_envblock_t *be)
1683 {
1684 	vdev_t *kid;
1685 	int rv = 0, rc;
1686 
1687 	STAILQ_FOREACH(kid, &vdev->v_children, v_childlink) {
1688 		if (kid->v_state != VDEV_STATE_HEALTHY)
1689 			continue;
1690 		rc = vdev_write_bootenv_impl(kid, be);
1691 		if (rv == 0)
1692 			rv = rc;
1693 	}
1694 
1695 	/*
1696 	 * Non-leaf vdevs do not have v_phys_write.
1697 	 */
1698 	if (vdev->v_phys_write == NULL)
1699 		return (rv);
1700 
1701 	for (int l = 0; l < VDEV_LABELS; l++) {
1702 		rc = vdev_label_write(vdev, l, be,
1703 		    offsetof(vdev_label_t, vl_be));
1704 		if (rc != 0) {
1705 			printf("failed to write bootenv to %s label %d: %d\n",
1706 			    vdev->v_name ? vdev->v_name : "unknown", l, rc);
1707 			rv = rc;
1708 		}
1709 	}
1710 	return (rv);
1711 }
1712 
1713 int
1714 vdev_write_bootenv(vdev_t *vdev, nvlist_t *nvl)
1715 {
1716 	vdev_boot_envblock_t *be;
1717 	nvlist_t nv, *nvp;
1718 	uint64_t version;
1719 	int rv;
1720 
1721 	if (nvl->nv_size > sizeof(be->vbe_bootenv))
1722 		return (E2BIG);
1723 
1724 	version = VB_RAW;
1725 	nvp = vdev_read_bootenv(vdev);
1726 	if (nvp != NULL) {
1727 		nvlist_find(nvp, BOOTENV_VERSION, DATA_TYPE_UINT64, NULL,
1728 		    &version, NULL);
1729 		nvlist_destroy(nvp);
1730 	}
1731 
1732 	be = calloc(1, sizeof(*be));
1733 	if (be == NULL)
1734 		return (ENOMEM);
1735 
1736 	be->vbe_version = version;
1737 	switch (version) {
1738 	case VB_RAW:
1739 		/*
1740 		 * If there is no envmap, we will just wipe bootenv.
1741 		 */
1742 		nvlist_find(nvl, GRUB_ENVMAP, DATA_TYPE_STRING, NULL,
1743 		    be->vbe_bootenv, NULL);
1744 		rv = 0;
1745 		break;
1746 
1747 	case VB_NVLIST:
1748 		nv.nv_header = nvl->nv_header;
1749 		nv.nv_asize = nvl->nv_asize;
1750 		nv.nv_size = nvl->nv_size;
1751 
1752 		bcopy(&nv.nv_header, be->vbe_bootenv, sizeof(nv.nv_header));
1753 		nv.nv_data = be->vbe_bootenv + sizeof(nvs_header_t);
1754 		bcopy(nvl->nv_data, nv.nv_data, nv.nv_size);
1755 		rv = nvlist_export(&nv);
1756 		break;
1757 
1758 	default:
1759 		rv = EINVAL;
1760 		break;
1761 	}
1762 
1763 	if (rv == 0) {
1764 		be->vbe_version = htobe64(be->vbe_version);
1765 		rv = vdev_write_bootenv_impl(vdev, be);
1766 	}
1767 	free(be);
1768 	return (rv);
1769 }
1770 
1771 /*
1772  * Read the bootenv area from pool label, return the nvlist from it.
1773  * We return from first successful read.
1774  */
1775 nvlist_t *
1776 vdev_read_bootenv(vdev_t *vdev)
1777 {
1778 	vdev_t *kid;
1779 	nvlist_t *benv;
1780 	vdev_boot_envblock_t *be;
1781 	char *command;
1782 	bool ok;
1783 	int rv;
1784 
1785 	STAILQ_FOREACH(kid, &vdev->v_children, v_childlink) {
1786 		if (kid->v_state != VDEV_STATE_HEALTHY)
1787 			continue;
1788 
1789 		benv = vdev_read_bootenv(kid);
1790 		if (benv != NULL)
1791 			return (benv);
1792 	}
1793 
1794 	be = malloc(sizeof (*be));
1795 	if (be == NULL)
1796 		return (NULL);
1797 
1798 	rv = 0;
1799 	for (int l = 0; l < VDEV_LABELS; l++) {
1800 		rv = vdev_label_read(vdev, l, be,
1801 		    offsetof(vdev_label_t, vl_be),
1802 		    sizeof (*be));
1803 		if (rv == 0)
1804 			break;
1805 	}
1806 	if (rv != 0) {
1807 		free(be);
1808 		return (NULL);
1809 	}
1810 
1811 	be->vbe_version = be64toh(be->vbe_version);
1812 	switch (be->vbe_version) {
1813 	case VB_RAW:
1814 		/*
1815 		 * we have textual data in vbe_bootenv, create nvlist
1816 		 * with key "envmap".
1817 		 */
1818 		benv = nvlist_create(NV_UNIQUE_NAME);
1819 		if (benv != NULL) {
1820 			if (*be->vbe_bootenv == '\0') {
1821 				nvlist_add_uint64(benv, BOOTENV_VERSION,
1822 				    VB_NVLIST);
1823 				break;
1824 			}
1825 			nvlist_add_uint64(benv, BOOTENV_VERSION, VB_RAW);
1826 			be->vbe_bootenv[sizeof (be->vbe_bootenv) - 1] = '\0';
1827 			nvlist_add_string(benv, GRUB_ENVMAP, be->vbe_bootenv);
1828 		}
1829 		break;
1830 
1831 	case VB_NVLIST:
1832 		benv = nvlist_import(be->vbe_bootenv, sizeof(be->vbe_bootenv));
1833 		break;
1834 
1835 	default:
1836 		command = (char *)be;
1837 		ok = false;
1838 
1839 		/* Check for legacy zfsbootcfg command string */
1840 		for (int i = 0; command[i] != '\0'; i++) {
1841 			if (iscntrl(command[i])) {
1842 				ok = false;
1843 				break;
1844 			} else {
1845 				ok = true;
1846 			}
1847 		}
1848 		benv = nvlist_create(NV_UNIQUE_NAME);
1849 		if (benv != NULL) {
1850 			if (ok)
1851 				nvlist_add_string(benv, FREEBSD_BOOTONCE,
1852 				    command);
1853 			else
1854 				nvlist_add_uint64(benv, BOOTENV_VERSION,
1855 				    VB_NVLIST);
1856 		}
1857 		break;
1858 	}
1859 	free(be);
1860 	return (benv);
1861 }
1862 
1863 static uint64_t
1864 vdev_get_label_asize(nvlist_t *nvl)
1865 {
1866 	nvlist_t *vdevs;
1867 	uint64_t asize;
1868 	const char *type;
1869 	int len;
1870 
1871 	asize = 0;
1872 	/* Get vdev tree */
1873 	if (nvlist_find(nvl, ZPOOL_CONFIG_VDEV_TREE, DATA_TYPE_NVLIST,
1874 	    NULL, &vdevs, NULL) != 0)
1875 		return (asize);
1876 
1877 	/*
1878 	 * Get vdev type. We will calculate asize for raidz, mirror and disk.
1879 	 * For raidz, the asize is raw size of all children.
1880 	 */
1881 	if (nvlist_find(vdevs, ZPOOL_CONFIG_TYPE, DATA_TYPE_STRING,
1882 	    NULL, &type, &len) != 0)
1883 		goto done;
1884 
1885 	if (memcmp(type, VDEV_TYPE_MIRROR, len) != 0 &&
1886 	    memcmp(type, VDEV_TYPE_DISK, len) != 0 &&
1887 	    memcmp(type, VDEV_TYPE_RAIDZ, len) != 0)
1888 		goto done;
1889 
1890 	if (nvlist_find(vdevs, ZPOOL_CONFIG_ASIZE, DATA_TYPE_UINT64,
1891 	    NULL, &asize, NULL) != 0)
1892 		goto done;
1893 
1894 	if (memcmp(type, VDEV_TYPE_RAIDZ, len) == 0) {
1895 		nvlist_t **kids;
1896 		int nkids;
1897 
1898 		if (nvlist_find(vdevs, ZPOOL_CONFIG_CHILDREN,
1899 		    DATA_TYPE_NVLIST_ARRAY, &nkids, &kids, NULL) != 0) {
1900 			asize = 0;
1901 			goto done;
1902 		}
1903 
1904 		asize /= nkids;
1905 		for (int i = 0; i < nkids; i++)
1906 			nvlist_destroy(kids[i]);
1907 		free(kids);
1908 	}
1909 
1910 	asize += VDEV_LABEL_START_SIZE + VDEV_LABEL_END_SIZE;
1911 done:
1912 	nvlist_destroy(vdevs);
1913 	return (asize);
1914 }
1915 
1916 static nvlist_t *
1917 vdev_label_read_config(vdev_t *vd, uint64_t txg)
1918 {
1919 	vdev_phys_t *label;
1920 	uint64_t best_txg = 0;
1921 	uint64_t label_txg = 0;
1922 	uint64_t asize;
1923 	nvlist_t *nvl = NULL, *tmp;
1924 	int error;
1925 
1926 	label = malloc(sizeof (vdev_phys_t));
1927 	if (label == NULL)
1928 		return (NULL);
1929 
1930 	for (int l = 0; l < VDEV_LABELS; l++) {
1931 		if (vdev_label_read(vd, l, label,
1932 		    offsetof(vdev_label_t, vl_vdev_phys),
1933 		    sizeof (vdev_phys_t)))
1934 			continue;
1935 
1936 		tmp = nvlist_import(label->vp_nvlist,
1937 		    sizeof(label->vp_nvlist));
1938 		if (tmp == NULL)
1939 			continue;
1940 
1941 		error = nvlist_find(tmp, ZPOOL_CONFIG_POOL_TXG,
1942 		    DATA_TYPE_UINT64, NULL, &label_txg, NULL);
1943 		if (error != 0 || label_txg == 0) {
1944 			nvlist_destroy(nvl);
1945 			nvl = tmp;
1946 			goto done;
1947 		}
1948 
1949 		if (label_txg <= txg && label_txg > best_txg) {
1950 			best_txg = label_txg;
1951 			nvlist_destroy(nvl);
1952 			nvl = tmp;
1953 			tmp = NULL;
1954 
1955 			/*
1956 			 * Use asize from pool config. We need this
1957 			 * because we can get bad value from BIOS.
1958 			 */
1959 			asize = vdev_get_label_asize(nvl);
1960 			if (asize != 0) {
1961 				vd->v_psize = asize;
1962 			}
1963 		}
1964 		nvlist_destroy(tmp);
1965 	}
1966 
1967 	if (best_txg == 0) {
1968 		nvlist_destroy(nvl);
1969 		nvl = NULL;
1970 	}
1971 done:
1972 	free(label);
1973 	return (nvl);
1974 }
1975 
1976 static void
1977 vdev_uberblock_load(vdev_t *vd, uberblock_t *ub)
1978 {
1979 	uberblock_t *buf;
1980 
1981 	buf = malloc(VDEV_UBERBLOCK_SIZE(vd));
1982 	if (buf == NULL)
1983 		return;
1984 
1985 	for (int l = 0; l < VDEV_LABELS; l++) {
1986 		for (int n = 0; n < VDEV_UBERBLOCK_COUNT(vd); n++) {
1987 			if (vdev_label_read(vd, l, buf,
1988 			    VDEV_UBERBLOCK_OFFSET(vd, n),
1989 			    VDEV_UBERBLOCK_SIZE(vd)))
1990 				continue;
1991 			if (uberblock_verify(buf) != 0)
1992 				continue;
1993 
1994 			if (vdev_uberblock_compare(buf, ub) > 0)
1995 				*ub = *buf;
1996 		}
1997 	}
1998 	free(buf);
1999 }
2000 
2001 static int
2002 vdev_probe(vdev_phys_read_t *_read, vdev_phys_write_t *_write, void *priv,
2003     spa_t **spap)
2004 {
2005 	vdev_t vtmp;
2006 	spa_t *spa;
2007 	vdev_t *vdev;
2008 	nvlist_t *nvl;
2009 	uint64_t val;
2010 	uint64_t guid, vdev_children;
2011 	uint64_t pool_txg, pool_guid;
2012 	const char *pool_name;
2013 	int rc, namelen;
2014 
2015 	/*
2016 	 * Load the vdev label and figure out which
2017 	 * uberblock is most current.
2018 	 */
2019 	memset(&vtmp, 0, sizeof(vtmp));
2020 	vtmp.v_phys_read = _read;
2021 	vtmp.v_phys_write = _write;
2022 	vtmp.v_priv = priv;
2023 	vtmp.v_psize = P2ALIGN(ldi_get_size(priv),
2024 	    (uint64_t)sizeof (vdev_label_t));
2025 
2026 	/* Test for minimum device size. */
2027 	if (vtmp.v_psize < SPA_MINDEVSIZE)
2028 		return (EIO);
2029 
2030 	nvl = vdev_label_read_config(&vtmp, UINT64_MAX);
2031 	if (nvl == NULL)
2032 		return (EIO);
2033 
2034 	if (nvlist_find(nvl, ZPOOL_CONFIG_VERSION, DATA_TYPE_UINT64,
2035 	    NULL, &val, NULL) != 0) {
2036 		nvlist_destroy(nvl);
2037 		return (EIO);
2038 	}
2039 
2040 	if (!SPA_VERSION_IS_SUPPORTED(val)) {
2041 		printf("ZFS: unsupported ZFS version %u (should be %u)\n",
2042 		    (unsigned)val, (unsigned)SPA_VERSION);
2043 		nvlist_destroy(nvl);
2044 		return (EIO);
2045 	}
2046 
2047 	/* Check ZFS features for read */
2048 	rc = nvlist_check_features_for_read(nvl);
2049 	if (rc != 0) {
2050 		nvlist_destroy(nvl);
2051 		return (EIO);
2052 	}
2053 
2054 	if (nvlist_find(nvl, ZPOOL_CONFIG_POOL_STATE, DATA_TYPE_UINT64,
2055 	    NULL, &val, NULL) != 0) {
2056 		nvlist_destroy(nvl);
2057 		return (EIO);
2058 	}
2059 
2060 	if (val == POOL_STATE_DESTROYED) {
2061 		/* We don't boot only from destroyed pools. */
2062 		nvlist_destroy(nvl);
2063 		return (EIO);
2064 	}
2065 
2066 	if (nvlist_find(nvl, ZPOOL_CONFIG_POOL_TXG, DATA_TYPE_UINT64,
2067 	    NULL, &pool_txg, NULL) != 0 ||
2068 	    nvlist_find(nvl, ZPOOL_CONFIG_POOL_GUID, DATA_TYPE_UINT64,
2069 	    NULL, &pool_guid, NULL) != 0 ||
2070 	    nvlist_find(nvl, ZPOOL_CONFIG_POOL_NAME, DATA_TYPE_STRING,
2071 	    NULL, &pool_name, &namelen) != 0) {
2072 		/*
2073 		 * Cache and spare devices end up here - just ignore
2074 		 * them.
2075 		 */
2076 		nvlist_destroy(nvl);
2077 		return (EIO);
2078 	}
2079 
2080 	/*
2081 	 * Create the pool if this is the first time we've seen it.
2082 	 */
2083 	spa = spa_find_by_guid(pool_guid);
2084 	if (spa == NULL) {
2085 		char *name;
2086 
2087 		nvlist_find(nvl, ZPOOL_CONFIG_VDEV_CHILDREN,
2088 		    DATA_TYPE_UINT64, NULL, &vdev_children, NULL);
2089 		name = malloc(namelen + 1);
2090 		if (name == NULL) {
2091 			nvlist_destroy(nvl);
2092 			return (ENOMEM);
2093 		}
2094 		bcopy(pool_name, name, namelen);
2095 		name[namelen] = '\0';
2096 		spa = spa_create(pool_guid, name);
2097 		free(name);
2098 		if (spa == NULL) {
2099 			nvlist_destroy(nvl);
2100 			return (ENOMEM);
2101 		}
2102 		spa->spa_root_vdev->v_nchildren = vdev_children;
2103 	}
2104 	if (pool_txg > spa->spa_txg)
2105 		spa->spa_txg = pool_txg;
2106 
2107 	/*
2108 	 * Get the vdev tree and create our in-core copy of it.
2109 	 * If we already have a vdev with this guid, this must
2110 	 * be some kind of alias (overlapping slices, dangerously dedicated
2111 	 * disks etc).
2112 	 */
2113 	if (nvlist_find(nvl, ZPOOL_CONFIG_GUID, DATA_TYPE_UINT64,
2114 	    NULL, &guid, NULL) != 0) {
2115 		nvlist_destroy(nvl);
2116 		return (EIO);
2117 	}
2118 	vdev = vdev_find(guid);
2119 	/* Has this vdev already been inited? */
2120 	if (vdev && vdev->v_phys_read) {
2121 		nvlist_destroy(nvl);
2122 		return (EIO);
2123 	}
2124 
2125 	rc = vdev_init_from_label(spa, nvl);
2126 	nvlist_destroy(nvl);
2127 	if (rc != 0)
2128 		return (rc);
2129 
2130 	/*
2131 	 * We should already have created an incomplete vdev for this
2132 	 * vdev. Find it and initialise it with our read proc.
2133 	 */
2134 	vdev = vdev_find(guid);
2135 	if (vdev != NULL) {
2136 		vdev->v_phys_read = _read;
2137 		vdev->v_phys_write = _write;
2138 		vdev->v_priv = priv;
2139 		vdev->v_psize = vtmp.v_psize;
2140 		/*
2141 		 * If no other state is set, mark vdev healthy.
2142 		 */
2143 		if (vdev->v_state == VDEV_STATE_UNKNOWN)
2144 			vdev->v_state = VDEV_STATE_HEALTHY;
2145 	} else {
2146 		printf("ZFS: inconsistent nvlist contents\n");
2147 		return (EIO);
2148 	}
2149 
2150 	if (vdev->v_islog)
2151 		spa->spa_with_log = vdev->v_islog;
2152 
2153 	/*
2154 	 * Re-evaluate top-level vdev state.
2155 	 */
2156 	vdev_set_state(vdev->v_top);
2157 
2158 	/*
2159 	 * Ok, we are happy with the pool so far. Lets find
2160 	 * the best uberblock and then we can actually access
2161 	 * the contents of the pool.
2162 	 */
2163 	vdev_uberblock_load(vdev, spa->spa_uberblock);
2164 
2165 	if (spap != NULL)
2166 		*spap = spa;
2167 	return (0);
2168 }
2169 
2170 static int
2171 ilog2(int n)
2172 {
2173 	int v;
2174 
2175 	for (v = 0; v < 32; v++)
2176 		if (n == (1 << v))
2177 			return (v);
2178 	return (-1);
2179 }
2180 
2181 static int
2182 zio_read_gang(const spa_t *spa, const blkptr_t *bp, void *buf)
2183 {
2184 	blkptr_t gbh_bp;
2185 	zio_gbh_phys_t zio_gb;
2186 	char *pbuf;
2187 	int i;
2188 
2189 	/* Artificial BP for gang block header. */
2190 	gbh_bp = *bp;
2191 	BP_SET_PSIZE(&gbh_bp, SPA_GANGBLOCKSIZE);
2192 	BP_SET_LSIZE(&gbh_bp, SPA_GANGBLOCKSIZE);
2193 	BP_SET_CHECKSUM(&gbh_bp, ZIO_CHECKSUM_GANG_HEADER);
2194 	BP_SET_COMPRESS(&gbh_bp, ZIO_COMPRESS_OFF);
2195 	for (i = 0; i < SPA_DVAS_PER_BP; i++)
2196 		DVA_SET_GANG(&gbh_bp.blk_dva[i], 0);
2197 
2198 	/* Read gang header block using the artificial BP. */
2199 	if (zio_read(spa, &gbh_bp, &zio_gb))
2200 		return (EIO);
2201 
2202 	pbuf = buf;
2203 	for (i = 0; i < SPA_GBH_NBLKPTRS; i++) {
2204 		blkptr_t *gbp = &zio_gb.zg_blkptr[i];
2205 
2206 		if (BP_IS_HOLE(gbp))
2207 			continue;
2208 		if (zio_read(spa, gbp, pbuf))
2209 			return (EIO);
2210 		pbuf += BP_GET_PSIZE(gbp);
2211 	}
2212 
2213 	if (zio_checksum_verify(spa, bp, buf))
2214 		return (EIO);
2215 	return (0);
2216 }
2217 
2218 static int
2219 zio_read(const spa_t *spa, const blkptr_t *bp, void *buf)
2220 {
2221 	int cpfunc = BP_GET_COMPRESS(bp);
2222 	uint64_t align, size;
2223 	void *pbuf;
2224 	int i, error;
2225 
2226 	/*
2227 	 * Process data embedded in block pointer
2228 	 */
2229 	if (BP_IS_EMBEDDED(bp)) {
2230 		ASSERT(BPE_GET_ETYPE(bp) == BP_EMBEDDED_TYPE_DATA);
2231 
2232 		size = BPE_GET_PSIZE(bp);
2233 		ASSERT(size <= BPE_PAYLOAD_SIZE);
2234 
2235 		if (cpfunc != ZIO_COMPRESS_OFF)
2236 			pbuf = malloc(size);
2237 		else
2238 			pbuf = buf;
2239 
2240 		if (pbuf == NULL)
2241 			return (ENOMEM);
2242 
2243 		decode_embedded_bp_compressed(bp, pbuf);
2244 		error = 0;
2245 
2246 		if (cpfunc != ZIO_COMPRESS_OFF) {
2247 			error = zio_decompress_data(cpfunc, pbuf,
2248 			    size, buf, BP_GET_LSIZE(bp));
2249 			free(pbuf);
2250 		}
2251 		if (error != 0)
2252 			printf("ZFS: i/o error - unable to decompress "
2253 			    "block pointer data, error %d\n", error);
2254 		return (error);
2255 	}
2256 
2257 	error = EIO;
2258 
2259 	for (i = 0; i < SPA_DVAS_PER_BP; i++) {
2260 		const dva_t *dva = &bp->blk_dva[i];
2261 		vdev_t *vdev;
2262 		vdev_list_t *vlist;
2263 		uint64_t vdevid;
2264 		off_t offset;
2265 
2266 		if (!dva->dva_word[0] && !dva->dva_word[1])
2267 			continue;
2268 
2269 		vdevid = DVA_GET_VDEV(dva);
2270 		offset = DVA_GET_OFFSET(dva);
2271 		vlist = &spa->spa_root_vdev->v_children;
2272 		STAILQ_FOREACH(vdev, vlist, v_childlink) {
2273 			if (vdev->v_id == vdevid)
2274 				break;
2275 		}
2276 		if (!vdev || !vdev->v_read)
2277 			continue;
2278 
2279 		size = BP_GET_PSIZE(bp);
2280 		if (vdev->v_read == vdev_raidz_read) {
2281 			align = 1ULL << vdev->v_ashift;
2282 			if (P2PHASE(size, align) != 0)
2283 				size = P2ROUNDUP(size, align);
2284 		}
2285 		if (size != BP_GET_PSIZE(bp) || cpfunc != ZIO_COMPRESS_OFF)
2286 			pbuf = malloc(size);
2287 		else
2288 			pbuf = buf;
2289 
2290 		if (pbuf == NULL) {
2291 			error = ENOMEM;
2292 			break;
2293 		}
2294 
2295 		if (DVA_GET_GANG(dva))
2296 			error = zio_read_gang(spa, bp, pbuf);
2297 		else
2298 			error = vdev->v_read(vdev, bp, pbuf, offset, size);
2299 		if (error == 0) {
2300 			if (cpfunc != ZIO_COMPRESS_OFF)
2301 				error = zio_decompress_data(cpfunc, pbuf,
2302 				    BP_GET_PSIZE(bp), buf, BP_GET_LSIZE(bp));
2303 			else if (size != BP_GET_PSIZE(bp))
2304 				bcopy(pbuf, buf, BP_GET_PSIZE(bp));
2305 		} else {
2306 			printf("zio_read error: %d\n", error);
2307 		}
2308 		if (buf != pbuf)
2309 			free(pbuf);
2310 		if (error == 0)
2311 			break;
2312 	}
2313 	if (error != 0)
2314 		printf("ZFS: i/o error - all block copies unavailable\n");
2315 
2316 	return (error);
2317 }
2318 
2319 static int
2320 dnode_read(const spa_t *spa, const dnode_phys_t *dnode, off_t offset,
2321     void *buf, size_t buflen)
2322 {
2323 	int ibshift = dnode->dn_indblkshift - SPA_BLKPTRSHIFT;
2324 	int bsize = dnode->dn_datablkszsec << SPA_MINBLOCKSHIFT;
2325 	int nlevels = dnode->dn_nlevels;
2326 	int i, rc;
2327 
2328 	if (bsize > SPA_MAXBLOCKSIZE) {
2329 		printf("ZFS: I/O error - blocks larger than %llu are not "
2330 		    "supported\n", SPA_MAXBLOCKSIZE);
2331 		return (EIO);
2332 	}
2333 
2334 	/*
2335 	 * Handle odd block sizes, mirrors dmu_read_impl().  Data can't exist
2336 	 * past the first block, so we'll clip the read to the portion of the
2337 	 * buffer within bsize and zero out the remainder.
2338 	 */
2339 	if (dnode->dn_maxblkid == 0) {
2340 		size_t newbuflen;
2341 
2342 		newbuflen = offset > bsize ? 0 : MIN(buflen, bsize - offset);
2343 		bzero((char *)buf + newbuflen, buflen - newbuflen);
2344 		buflen = newbuflen;
2345 	}
2346 
2347 	/*
2348 	 * Note: bsize may not be a power of two here so we need to do an
2349 	 * actual divide rather than a bitshift.
2350 	 */
2351 	while (buflen > 0) {
2352 		uint64_t bn = offset / bsize;
2353 		int boff = offset % bsize;
2354 		int ibn;
2355 		const blkptr_t *indbp;
2356 		blkptr_t bp;
2357 
2358 		if (bn > dnode->dn_maxblkid)
2359 			return (EIO);
2360 
2361 		if (dnode == dnode_cache_obj && bn == dnode_cache_bn)
2362 			goto cached;
2363 
2364 		indbp = dnode->dn_blkptr;
2365 		for (i = 0; i < nlevels; i++) {
2366 			/*
2367 			 * Copy the bp from the indirect array so that
2368 			 * we can re-use the scratch buffer for multi-level
2369 			 * objects.
2370 			 */
2371 			ibn = bn >> ((nlevels - i - 1) * ibshift);
2372 			ibn &= ((1 << ibshift) - 1);
2373 			bp = indbp[ibn];
2374 			if (BP_IS_HOLE(&bp)) {
2375 				memset(dnode_cache_buf, 0, bsize);
2376 				break;
2377 			}
2378 			rc = zio_read(spa, &bp, dnode_cache_buf);
2379 			if (rc)
2380 				return (rc);
2381 			indbp = (const blkptr_t *) dnode_cache_buf;
2382 		}
2383 		dnode_cache_obj = dnode;
2384 		dnode_cache_bn = bn;
2385 	cached:
2386 
2387 		/*
2388 		 * The buffer contains our data block. Copy what we
2389 		 * need from it and loop.
2390 		 */
2391 		i = bsize - boff;
2392 		if (i > buflen) i = buflen;
2393 		memcpy(buf, &dnode_cache_buf[boff], i);
2394 		buf = ((char *)buf) + i;
2395 		offset += i;
2396 		buflen -= i;
2397 	}
2398 
2399 	return (0);
2400 }
2401 
2402 /*
2403  * Lookup a value in a microzap directory.
2404  */
2405 static int
2406 mzap_lookup(const mzap_phys_t *mz, size_t size, const char *name,
2407     uint64_t *value)
2408 {
2409 	const mzap_ent_phys_t *mze;
2410 	int chunks, i;
2411 
2412 	/*
2413 	 * Microzap objects use exactly one block. Read the whole
2414 	 * thing.
2415 	 */
2416 	chunks = size / MZAP_ENT_LEN - 1;
2417 	for (i = 0; i < chunks; i++) {
2418 		mze = &mz->mz_chunk[i];
2419 		if (strcmp(mze->mze_name, name) == 0) {
2420 			*value = mze->mze_value;
2421 			return (0);
2422 		}
2423 	}
2424 
2425 	return (ENOENT);
2426 }
2427 
2428 /*
2429  * Compare a name with a zap leaf entry. Return non-zero if the name
2430  * matches.
2431  */
2432 static int
2433 fzap_name_equal(const zap_leaf_t *zl, const zap_leaf_chunk_t *zc,
2434     const char *name)
2435 {
2436 	size_t namelen;
2437 	const zap_leaf_chunk_t *nc;
2438 	const char *p;
2439 
2440 	namelen = zc->l_entry.le_name_numints;
2441 
2442 	nc = &ZAP_LEAF_CHUNK(zl, zc->l_entry.le_name_chunk);
2443 	p = name;
2444 	while (namelen > 0) {
2445 		size_t len;
2446 
2447 		len = namelen;
2448 		if (len > ZAP_LEAF_ARRAY_BYTES)
2449 			len = ZAP_LEAF_ARRAY_BYTES;
2450 		if (memcmp(p, nc->l_array.la_array, len))
2451 			return (0);
2452 		p += len;
2453 		namelen -= len;
2454 		nc = &ZAP_LEAF_CHUNK(zl, nc->l_array.la_next);
2455 	}
2456 
2457 	return (1);
2458 }
2459 
2460 /*
2461  * Extract a uint64_t value from a zap leaf entry.
2462  */
2463 static uint64_t
2464 fzap_leaf_value(const zap_leaf_t *zl, const zap_leaf_chunk_t *zc)
2465 {
2466 	const zap_leaf_chunk_t *vc;
2467 	int i;
2468 	uint64_t value;
2469 	const uint8_t *p;
2470 
2471 	vc = &ZAP_LEAF_CHUNK(zl, zc->l_entry.le_value_chunk);
2472 	for (i = 0, value = 0, p = vc->l_array.la_array; i < 8; i++) {
2473 		value = (value << 8) | p[i];
2474 	}
2475 
2476 	return (value);
2477 }
2478 
2479 static void
2480 stv(int len, void *addr, uint64_t value)
2481 {
2482 	switch (len) {
2483 	case 1:
2484 		*(uint8_t *)addr = value;
2485 		return;
2486 	case 2:
2487 		*(uint16_t *)addr = value;
2488 		return;
2489 	case 4:
2490 		*(uint32_t *)addr = value;
2491 		return;
2492 	case 8:
2493 		*(uint64_t *)addr = value;
2494 		return;
2495 	}
2496 }
2497 
2498 /*
2499  * Extract a array from a zap leaf entry.
2500  */
2501 static void
2502 fzap_leaf_array(const zap_leaf_t *zl, const zap_leaf_chunk_t *zc,
2503     uint64_t integer_size, uint64_t num_integers, void *buf)
2504 {
2505 	uint64_t array_int_len = zc->l_entry.le_value_intlen;
2506 	uint64_t value = 0;
2507 	uint64_t *u64 = buf;
2508 	char *p = buf;
2509 	int len = MIN(zc->l_entry.le_value_numints, num_integers);
2510 	int chunk = zc->l_entry.le_value_chunk;
2511 	int byten = 0;
2512 
2513 	if (integer_size == 8 && len == 1) {
2514 		*u64 = fzap_leaf_value(zl, zc);
2515 		return;
2516 	}
2517 
2518 	while (len > 0) {
2519 		struct zap_leaf_array *la = &ZAP_LEAF_CHUNK(zl, chunk).l_array;
2520 		int i;
2521 
2522 		ASSERT3U(chunk, <, ZAP_LEAF_NUMCHUNKS(zl));
2523 		for (i = 0; i < ZAP_LEAF_ARRAY_BYTES && len > 0; i++) {
2524 			value = (value << 8) | la->la_array[i];
2525 			byten++;
2526 			if (byten == array_int_len) {
2527 				stv(integer_size, p, value);
2528 				byten = 0;
2529 				len--;
2530 				if (len == 0)
2531 					return;
2532 				p += integer_size;
2533 			}
2534 		}
2535 		chunk = la->la_next;
2536 	}
2537 }
2538 
2539 static int
2540 fzap_check_size(uint64_t integer_size, uint64_t num_integers)
2541 {
2542 
2543 	switch (integer_size) {
2544 	case 1:
2545 	case 2:
2546 	case 4:
2547 	case 8:
2548 		break;
2549 	default:
2550 		return (EINVAL);
2551 	}
2552 
2553 	if (integer_size * num_integers > ZAP_MAXVALUELEN)
2554 		return (E2BIG);
2555 
2556 	return (0);
2557 }
2558 
2559 static void
2560 zap_leaf_free(zap_leaf_t *leaf)
2561 {
2562 	free(leaf->l_phys);
2563 	free(leaf);
2564 }
2565 
2566 static int
2567 zap_get_leaf_byblk(fat_zap_t *zap, uint64_t blk, zap_leaf_t **lp)
2568 {
2569 	int bs = FZAP_BLOCK_SHIFT(zap);
2570 	int err;
2571 
2572 	*lp = malloc(sizeof(**lp));
2573 	if (*lp == NULL)
2574 		return (ENOMEM);
2575 
2576 	(*lp)->l_bs = bs;
2577 	(*lp)->l_phys = malloc(1 << bs);
2578 
2579 	if ((*lp)->l_phys == NULL) {
2580 		free(*lp);
2581 		return (ENOMEM);
2582 	}
2583 	err = dnode_read(zap->zap_spa, zap->zap_dnode, blk << bs, (*lp)->l_phys,
2584 	    1 << bs);
2585 	if (err != 0) {
2586 		zap_leaf_free(*lp);
2587 	}
2588 	return (err);
2589 }
2590 
2591 static int
2592 zap_table_load(fat_zap_t *zap, zap_table_phys_t *tbl, uint64_t idx,
2593     uint64_t *valp)
2594 {
2595 	int bs = FZAP_BLOCK_SHIFT(zap);
2596 	uint64_t blk = idx >> (bs - 3);
2597 	uint64_t off = idx & ((1 << (bs - 3)) - 1);
2598 	uint64_t *buf;
2599 	int rc;
2600 
2601 	buf = malloc(1 << zap->zap_block_shift);
2602 	if (buf == NULL)
2603 		return (ENOMEM);
2604 	rc = dnode_read(zap->zap_spa, zap->zap_dnode, (tbl->zt_blk + blk) << bs,
2605 	    buf, 1 << zap->zap_block_shift);
2606 	if (rc == 0)
2607 		*valp = buf[off];
2608 	free(buf);
2609 	return (rc);
2610 }
2611 
2612 static int
2613 zap_idx_to_blk(fat_zap_t *zap, uint64_t idx, uint64_t *valp)
2614 {
2615 	if (zap->zap_phys->zap_ptrtbl.zt_numblks == 0) {
2616 		*valp = ZAP_EMBEDDED_PTRTBL_ENT(zap, idx);
2617 		return (0);
2618 	} else {
2619 		return (zap_table_load(zap, &zap->zap_phys->zap_ptrtbl,
2620 		    idx, valp));
2621 	}
2622 }
2623 
2624 #define	ZAP_HASH_IDX(hash, n)	(((n) == 0) ? 0 : ((hash) >> (64 - (n))))
2625 static int
2626 zap_deref_leaf(fat_zap_t *zap, uint64_t h, zap_leaf_t **lp)
2627 {
2628 	uint64_t idx, blk;
2629 	int err;
2630 
2631 	idx = ZAP_HASH_IDX(h, zap->zap_phys->zap_ptrtbl.zt_shift);
2632 	err = zap_idx_to_blk(zap, idx, &blk);
2633 	if (err != 0)
2634 		return (err);
2635 	return (zap_get_leaf_byblk(zap, blk, lp));
2636 }
2637 
2638 #define	CHAIN_END	0xffff	/* end of the chunk chain */
2639 #define	LEAF_HASH(l, h) \
2640 	((ZAP_LEAF_HASH_NUMENTRIES(l)-1) & \
2641 	((h) >> \
2642 	(64 - ZAP_LEAF_HASH_SHIFT(l) - (l)->l_phys->l_hdr.lh_prefix_len)))
2643 #define	LEAF_HASH_ENTPTR(l, h)	(&(l)->l_phys->l_hash[LEAF_HASH(l, h)])
2644 
2645 static int
2646 zap_leaf_lookup(zap_leaf_t *zl, uint64_t hash, const char *name,
2647     uint64_t integer_size, uint64_t num_integers, void *value)
2648 {
2649 	int rc;
2650 	uint16_t *chunkp;
2651 	struct zap_leaf_entry *le;
2652 
2653 	/*
2654 	 * Make sure this chunk matches our hash.
2655 	 */
2656 	if (zl->l_phys->l_hdr.lh_prefix_len > 0 &&
2657 	    zl->l_phys->l_hdr.lh_prefix !=
2658 	    hash >> (64 - zl->l_phys->l_hdr.lh_prefix_len))
2659 		return (EIO);
2660 
2661 	rc = ENOENT;
2662 	for (chunkp = LEAF_HASH_ENTPTR(zl, hash);
2663 	    *chunkp != CHAIN_END; chunkp = &le->le_next) {
2664 		zap_leaf_chunk_t *zc;
2665 		uint16_t chunk = *chunkp;
2666 
2667 		le = ZAP_LEAF_ENTRY(zl, chunk);
2668 		if (le->le_hash != hash)
2669 			continue;
2670 		zc = &ZAP_LEAF_CHUNK(zl, chunk);
2671 		if (fzap_name_equal(zl, zc, name)) {
2672 			if (zc->l_entry.le_value_intlen > integer_size) {
2673 				rc = EINVAL;
2674 			} else {
2675 				fzap_leaf_array(zl, zc, integer_size,
2676 				    num_integers, value);
2677 				rc = 0;
2678 			}
2679 			break;
2680 		}
2681 	}
2682 	return (rc);
2683 }
2684 
2685 /*
2686  * Lookup a value in a fatzap directory.
2687  */
2688 static int
2689 fzap_lookup(const spa_t *spa, const dnode_phys_t *dnode, zap_phys_t *zh,
2690     const char *name, uint64_t integer_size, uint64_t num_integers,
2691     void *value)
2692 {
2693 	int bsize = dnode->dn_datablkszsec << SPA_MINBLOCKSHIFT;
2694 	fat_zap_t z;
2695 	zap_leaf_t *zl;
2696 	uint64_t hash;
2697 	int rc;
2698 
2699 	if (zh->zap_magic != ZAP_MAGIC)
2700 		return (EIO);
2701 
2702 	if ((rc = fzap_check_size(integer_size, num_integers)) != 0) {
2703 		return (rc);
2704 	}
2705 
2706 	z.zap_block_shift = ilog2(bsize);
2707 	z.zap_phys = zh;
2708 	z.zap_spa = spa;
2709 	z.zap_dnode = dnode;
2710 
2711 	hash = zap_hash(zh->zap_salt, name);
2712 	rc = zap_deref_leaf(&z, hash, &zl);
2713 	if (rc != 0)
2714 		return (rc);
2715 
2716 	rc = zap_leaf_lookup(zl, hash, name, integer_size, num_integers, value);
2717 
2718 	zap_leaf_free(zl);
2719 	return (rc);
2720 }
2721 
2722 /*
2723  * Lookup a name in a zap object and return its value as a uint64_t.
2724  */
2725 static int
2726 zap_lookup(const spa_t *spa, const dnode_phys_t *dnode, const char *name,
2727     uint64_t integer_size, uint64_t num_integers, void *value)
2728 {
2729 	int rc;
2730 	zap_phys_t *zap;
2731 	size_t size = dnode->dn_datablkszsec << SPA_MINBLOCKSHIFT;
2732 
2733 	zap = malloc(size);
2734 	if (zap == NULL)
2735 		return (ENOMEM);
2736 
2737 	rc = dnode_read(spa, dnode, 0, zap, size);
2738 	if (rc)
2739 		goto done;
2740 
2741 	switch (zap->zap_block_type) {
2742 	case ZBT_MICRO:
2743 		rc = mzap_lookup((const mzap_phys_t *)zap, size, name, value);
2744 		break;
2745 	case ZBT_HEADER:
2746 		rc = fzap_lookup(spa, dnode, zap, name, integer_size,
2747 		    num_integers, value);
2748 		break;
2749 	default:
2750 		printf("ZFS: invalid zap_type=%" PRIx64 "\n",
2751 		    zap->zap_block_type);
2752 		rc = EIO;
2753 	}
2754 done:
2755 	free(zap);
2756 	return (rc);
2757 }
2758 
2759 /*
2760  * List a microzap directory.
2761  */
2762 static int
2763 mzap_list(const mzap_phys_t *mz, size_t size,
2764     int (*callback)(const char *, uint64_t))
2765 {
2766 	const mzap_ent_phys_t *mze;
2767 	int chunks, i, rc;
2768 
2769 	/*
2770 	 * Microzap objects use exactly one block. Read the whole
2771 	 * thing.
2772 	 */
2773 	rc = 0;
2774 	chunks = size / MZAP_ENT_LEN - 1;
2775 	for (i = 0; i < chunks; i++) {
2776 		mze = &mz->mz_chunk[i];
2777 		if (mze->mze_name[0]) {
2778 			rc = callback(mze->mze_name, mze->mze_value);
2779 			if (rc != 0)
2780 				break;
2781 		}
2782 	}
2783 
2784 	return (rc);
2785 }
2786 
2787 /*
2788  * List a fatzap directory.
2789  */
2790 static int
2791 fzap_list(const spa_t *spa, const dnode_phys_t *dnode, zap_phys_t *zh,
2792     int (*callback)(const char *, uint64_t))
2793 {
2794 	int bsize = dnode->dn_datablkszsec << SPA_MINBLOCKSHIFT;
2795 	fat_zap_t z;
2796 	uint64_t i;
2797 	int j, rc;
2798 
2799 	if (zh->zap_magic != ZAP_MAGIC)
2800 		return (EIO);
2801 
2802 	z.zap_block_shift = ilog2(bsize);
2803 	z.zap_phys = zh;
2804 
2805 	/*
2806 	 * This assumes that the leaf blocks start at block 1. The
2807 	 * documentation isn't exactly clear on this.
2808 	 */
2809 	zap_leaf_t zl;
2810 	zl.l_bs = z.zap_block_shift;
2811 	zl.l_phys = malloc(bsize);
2812 	if (zl.l_phys == NULL)
2813 		return (ENOMEM);
2814 
2815 	for (i = 0; i < zh->zap_num_leafs; i++) {
2816 		off_t off = ((off_t)(i + 1)) << zl.l_bs;
2817 		char name[256], *p;
2818 		uint64_t value;
2819 
2820 		if (dnode_read(spa, dnode, off, zl.l_phys, bsize)) {
2821 			free(zl.l_phys);
2822 			return (EIO);
2823 		}
2824 
2825 		for (j = 0; j < ZAP_LEAF_NUMCHUNKS(&zl); j++) {
2826 			zap_leaf_chunk_t *zc, *nc;
2827 			int namelen;
2828 
2829 			zc = &ZAP_LEAF_CHUNK(&zl, j);
2830 			if (zc->l_entry.le_type != ZAP_CHUNK_ENTRY)
2831 				continue;
2832 			namelen = zc->l_entry.le_name_numints;
2833 			if (namelen > sizeof(name))
2834 				namelen = sizeof(name);
2835 
2836 			/*
2837 			 * Paste the name back together.
2838 			 */
2839 			nc = &ZAP_LEAF_CHUNK(&zl, zc->l_entry.le_name_chunk);
2840 			p = name;
2841 			while (namelen > 0) {
2842 				int len;
2843 				len = namelen;
2844 				if (len > ZAP_LEAF_ARRAY_BYTES)
2845 					len = ZAP_LEAF_ARRAY_BYTES;
2846 				memcpy(p, nc->l_array.la_array, len);
2847 				p += len;
2848 				namelen -= len;
2849 				nc = &ZAP_LEAF_CHUNK(&zl, nc->l_array.la_next);
2850 			}
2851 
2852 			/*
2853 			 * Assume the first eight bytes of the value are
2854 			 * a uint64_t.
2855 			 */
2856 			value = fzap_leaf_value(&zl, zc);
2857 
2858 			/* printf("%s 0x%jx\n", name, (uintmax_t)value); */
2859 			rc = callback((const char *)name, value);
2860 			if (rc != 0) {
2861 				free(zl.l_phys);
2862 				return (rc);
2863 			}
2864 		}
2865 	}
2866 
2867 	free(zl.l_phys);
2868 	return (0);
2869 }
2870 
2871 static int zfs_printf(const char *name, uint64_t value __unused)
2872 {
2873 
2874 	printf("%s\n", name);
2875 
2876 	return (0);
2877 }
2878 
2879 /*
2880  * List a zap directory.
2881  */
2882 static int
2883 zap_list(const spa_t *spa, const dnode_phys_t *dnode)
2884 {
2885 	zap_phys_t *zap;
2886 	size_t size = dnode->dn_datablkszsec << SPA_MINBLOCKSHIFT;
2887 	int rc;
2888 
2889 	zap = malloc(size);
2890 	if (zap == NULL)
2891 		return (ENOMEM);
2892 
2893 	rc = dnode_read(spa, dnode, 0, zap, size);
2894 	if (rc == 0) {
2895 		if (zap->zap_block_type == ZBT_MICRO)
2896 			rc = mzap_list((const mzap_phys_t *)zap, size,
2897 			    zfs_printf);
2898 		else
2899 			rc = fzap_list(spa, dnode, zap, zfs_printf);
2900 	}
2901 	free(zap);
2902 	return (rc);
2903 }
2904 
2905 static int
2906 objset_get_dnode(const spa_t *spa, const objset_phys_t *os, uint64_t objnum,
2907     dnode_phys_t *dnode)
2908 {
2909 	off_t offset;
2910 
2911 	offset = objnum * sizeof(dnode_phys_t);
2912 	return dnode_read(spa, &os->os_meta_dnode, offset,
2913 		dnode, sizeof(dnode_phys_t));
2914 }
2915 
2916 /*
2917  * Lookup a name in a microzap directory.
2918  */
2919 static int
2920 mzap_rlookup(const mzap_phys_t *mz, size_t size, char *name, uint64_t value)
2921 {
2922 	const mzap_ent_phys_t *mze;
2923 	int chunks, i;
2924 
2925 	/*
2926 	 * Microzap objects use exactly one block. Read the whole
2927 	 * thing.
2928 	 */
2929 	chunks = size / MZAP_ENT_LEN - 1;
2930 	for (i = 0; i < chunks; i++) {
2931 		mze = &mz->mz_chunk[i];
2932 		if (value == mze->mze_value) {
2933 			strcpy(name, mze->mze_name);
2934 			return (0);
2935 		}
2936 	}
2937 
2938 	return (ENOENT);
2939 }
2940 
2941 static void
2942 fzap_name_copy(const zap_leaf_t *zl, const zap_leaf_chunk_t *zc, char *name)
2943 {
2944 	size_t namelen;
2945 	const zap_leaf_chunk_t *nc;
2946 	char *p;
2947 
2948 	namelen = zc->l_entry.le_name_numints;
2949 
2950 	nc = &ZAP_LEAF_CHUNK(zl, zc->l_entry.le_name_chunk);
2951 	p = name;
2952 	while (namelen > 0) {
2953 		size_t len;
2954 		len = namelen;
2955 		if (len > ZAP_LEAF_ARRAY_BYTES)
2956 			len = ZAP_LEAF_ARRAY_BYTES;
2957 		memcpy(p, nc->l_array.la_array, len);
2958 		p += len;
2959 		namelen -= len;
2960 		nc = &ZAP_LEAF_CHUNK(zl, nc->l_array.la_next);
2961 	}
2962 
2963 	*p = '\0';
2964 }
2965 
2966 static int
2967 fzap_rlookup(const spa_t *spa, const dnode_phys_t *dnode, zap_phys_t *zh,
2968     char *name, uint64_t value)
2969 {
2970 	int bsize = dnode->dn_datablkszsec << SPA_MINBLOCKSHIFT;
2971 	fat_zap_t z;
2972 	uint64_t i;
2973 	int j, rc;
2974 
2975 	if (zh->zap_magic != ZAP_MAGIC)
2976 		return (EIO);
2977 
2978 	z.zap_block_shift = ilog2(bsize);
2979 	z.zap_phys = zh;
2980 
2981 	/*
2982 	 * This assumes that the leaf blocks start at block 1. The
2983 	 * documentation isn't exactly clear on this.
2984 	 */
2985 	zap_leaf_t zl;
2986 	zl.l_bs = z.zap_block_shift;
2987 	zl.l_phys = malloc(bsize);
2988 	if (zl.l_phys == NULL)
2989 		return (ENOMEM);
2990 
2991 	for (i = 0; i < zh->zap_num_leafs; i++) {
2992 		off_t off = ((off_t)(i + 1)) << zl.l_bs;
2993 
2994 		rc = dnode_read(spa, dnode, off, zl.l_phys, bsize);
2995 		if (rc != 0)
2996 			goto done;
2997 
2998 		for (j = 0; j < ZAP_LEAF_NUMCHUNKS(&zl); j++) {
2999 			zap_leaf_chunk_t *zc;
3000 
3001 			zc = &ZAP_LEAF_CHUNK(&zl, j);
3002 			if (zc->l_entry.le_type != ZAP_CHUNK_ENTRY)
3003 				continue;
3004 			if (zc->l_entry.le_value_intlen != 8 ||
3005 			    zc->l_entry.le_value_numints != 1)
3006 				continue;
3007 
3008 			if (fzap_leaf_value(&zl, zc) == value) {
3009 				fzap_name_copy(&zl, zc, name);
3010 				goto done;
3011 			}
3012 		}
3013 	}
3014 
3015 	rc = ENOENT;
3016 done:
3017 	free(zl.l_phys);
3018 	return (rc);
3019 }
3020 
3021 static int
3022 zap_rlookup(const spa_t *spa, const dnode_phys_t *dnode, char *name,
3023     uint64_t value)
3024 {
3025 	zap_phys_t *zap;
3026 	size_t size = dnode->dn_datablkszsec << SPA_MINBLOCKSHIFT;
3027 	int rc;
3028 
3029 	zap = malloc(size);
3030 	if (zap == NULL)
3031 		return (ENOMEM);
3032 
3033 	rc = dnode_read(spa, dnode, 0, zap, size);
3034 	if (rc == 0) {
3035 		if (zap->zap_block_type == ZBT_MICRO)
3036 			rc = mzap_rlookup((const mzap_phys_t *)zap, size,
3037 			    name, value);
3038 		else
3039 			rc = fzap_rlookup(spa, dnode, zap, name, value);
3040 	}
3041 	free(zap);
3042 	return (rc);
3043 }
3044 
3045 static int
3046 zfs_rlookup(const spa_t *spa, uint64_t objnum, char *result)
3047 {
3048 	char name[256];
3049 	char component[256];
3050 	uint64_t dir_obj, parent_obj, child_dir_zapobj;
3051 	dnode_phys_t child_dir_zap, snapnames_zap, dataset, dir, parent;
3052 	dsl_dir_phys_t *dd;
3053 	dsl_dataset_phys_t *ds;
3054 	char *p;
3055 	int len;
3056 	boolean_t issnap = B_FALSE;
3057 
3058 	p = &name[sizeof(name) - 1];
3059 	*p = '\0';
3060 
3061 	if (objset_get_dnode(spa, spa->spa_mos, objnum, &dataset)) {
3062 		printf("ZFS: can't find dataset %ju\n", (uintmax_t)objnum);
3063 		return (EIO);
3064 	}
3065 	ds = (dsl_dataset_phys_t *)&dataset.dn_bonus;
3066 	dir_obj = ds->ds_dir_obj;
3067 	if (ds->ds_snapnames_zapobj == 0)
3068 		issnap = B_TRUE;
3069 
3070 	for (;;) {
3071 		if (objset_get_dnode(spa, spa->spa_mos, dir_obj, &dir) != 0)
3072 			return (EIO);
3073 		dd = (dsl_dir_phys_t *)&dir.dn_bonus;
3074 
3075 		/* Actual loop condition. */
3076 		parent_obj = dd->dd_parent_obj;
3077 		if (parent_obj == 0)
3078 			break;
3079 
3080 		if (objset_get_dnode(spa, spa->spa_mos, parent_obj,
3081 		    &parent) != 0)
3082 			return (EIO);
3083 		dd = (dsl_dir_phys_t *)&parent.dn_bonus;
3084 		if (issnap == B_TRUE) {
3085 			/*
3086 			 * The dataset we are looking up is a snapshot
3087 			 * the dir_obj is the parent already, we don't want
3088 			 * the grandparent just yet. Reset to the parent.
3089 			 */
3090 			dd = (dsl_dir_phys_t *)&dir.dn_bonus;
3091 			/* Lookup the dataset to get the snapname ZAP */
3092 			if (objset_get_dnode(spa, spa->spa_mos,
3093 			    dd->dd_head_dataset_obj, &dataset))
3094 				return (EIO);
3095 			ds = (dsl_dataset_phys_t *)&dataset.dn_bonus;
3096 			if (objset_get_dnode(spa, spa->spa_mos,
3097 			    ds->ds_snapnames_zapobj, &snapnames_zap) != 0)
3098 				return (EIO);
3099 			/* Get the name of the snapshot */
3100 			if (zap_rlookup(spa, &snapnames_zap, component,
3101 			    objnum) != 0)
3102 				return (EIO);
3103 			len = strlen(component);
3104 			p -= len;
3105 			memcpy(p, component, len);
3106 			--p;
3107 			*p = '@';
3108 			issnap = B_FALSE;
3109 			continue;
3110 		}
3111 
3112 		child_dir_zapobj = dd->dd_child_dir_zapobj;
3113 		if (objset_get_dnode(spa, spa->spa_mos, child_dir_zapobj,
3114 		    &child_dir_zap) != 0)
3115 			return (EIO);
3116 		if (zap_rlookup(spa, &child_dir_zap, component, dir_obj) != 0)
3117 			return (EIO);
3118 
3119 		len = strlen(component);
3120 		p -= len;
3121 		memcpy(p, component, len);
3122 		--p;
3123 		*p = '/';
3124 
3125 		/* Actual loop iteration. */
3126 		dir_obj = parent_obj;
3127 	}
3128 
3129 	if (*p != '\0')
3130 		++p;
3131 	strcpy(result, p);
3132 
3133 	return (0);
3134 }
3135 
3136 static int
3137 zfs_lookup_dataset(const spa_t *spa, const char *name, uint64_t *objnum)
3138 {
3139 	char element[256];
3140 	uint64_t dir_obj, child_dir_zapobj;
3141 	dnode_phys_t child_dir_zap, snapnames_zap, dir, dataset;
3142 	dsl_dir_phys_t *dd;
3143 	dsl_dataset_phys_t *ds;
3144 	const char *p, *q;
3145 	boolean_t issnap = B_FALSE;
3146 
3147 	if (objset_get_dnode(spa, spa->spa_mos,
3148 	    DMU_POOL_DIRECTORY_OBJECT, &dir))
3149 		return (EIO);
3150 	if (zap_lookup(spa, &dir, DMU_POOL_ROOT_DATASET, sizeof (dir_obj),
3151 	    1, &dir_obj))
3152 		return (EIO);
3153 
3154 	p = name;
3155 	for (;;) {
3156 		if (objset_get_dnode(spa, spa->spa_mos, dir_obj, &dir))
3157 			return (EIO);
3158 		dd = (dsl_dir_phys_t *)&dir.dn_bonus;
3159 
3160 		while (*p == '/')
3161 			p++;
3162 		/* Actual loop condition #1. */
3163 		if (*p == '\0')
3164 			break;
3165 
3166 		q = strchr(p, '/');
3167 		if (q) {
3168 			memcpy(element, p, q - p);
3169 			element[q - p] = '\0';
3170 			p = q + 1;
3171 		} else {
3172 			strcpy(element, p);
3173 			p += strlen(p);
3174 		}
3175 
3176 		if (issnap == B_TRUE) {
3177 		        if (objset_get_dnode(spa, spa->spa_mos,
3178 			    dd->dd_head_dataset_obj, &dataset))
3179 		                return (EIO);
3180 			ds = (dsl_dataset_phys_t *)&dataset.dn_bonus;
3181 			if (objset_get_dnode(spa, spa->spa_mos,
3182 			    ds->ds_snapnames_zapobj, &snapnames_zap) != 0)
3183 				return (EIO);
3184 			/* Actual loop condition #2. */
3185 			if (zap_lookup(spa, &snapnames_zap, element,
3186 			    sizeof (dir_obj), 1, &dir_obj) != 0)
3187 				return (ENOENT);
3188 			*objnum = dir_obj;
3189 			return (0);
3190 		} else if ((q = strchr(element, '@')) != NULL) {
3191 			issnap = B_TRUE;
3192 			element[q - element] = '\0';
3193 			p = q + 1;
3194 		}
3195 		child_dir_zapobj = dd->dd_child_dir_zapobj;
3196 		if (objset_get_dnode(spa, spa->spa_mos, child_dir_zapobj,
3197 		    &child_dir_zap) != 0)
3198 			return (EIO);
3199 
3200 		/* Actual loop condition #2. */
3201 		if (zap_lookup(spa, &child_dir_zap, element, sizeof (dir_obj),
3202 		    1, &dir_obj) != 0)
3203 			return (ENOENT);
3204 	}
3205 
3206 	*objnum = dd->dd_head_dataset_obj;
3207 	return (0);
3208 }
3209 
3210 #ifndef BOOT2
3211 static int
3212 zfs_list_dataset(const spa_t *spa, uint64_t objnum/*, int pos, char *entry*/)
3213 {
3214 	uint64_t dir_obj, child_dir_zapobj;
3215 	dnode_phys_t child_dir_zap, dir, dataset;
3216 	dsl_dataset_phys_t *ds;
3217 	dsl_dir_phys_t *dd;
3218 
3219 	if (objset_get_dnode(spa, spa->spa_mos, objnum, &dataset)) {
3220 		printf("ZFS: can't find dataset %ju\n", (uintmax_t)objnum);
3221 		return (EIO);
3222 	}
3223 	ds = (dsl_dataset_phys_t *)&dataset.dn_bonus;
3224 	dir_obj = ds->ds_dir_obj;
3225 
3226 	if (objset_get_dnode(spa, spa->spa_mos, dir_obj, &dir)) {
3227 		printf("ZFS: can't find dirobj %ju\n", (uintmax_t)dir_obj);
3228 		return (EIO);
3229 	}
3230 	dd = (dsl_dir_phys_t *)&dir.dn_bonus;
3231 
3232 	child_dir_zapobj = dd->dd_child_dir_zapobj;
3233 	if (objset_get_dnode(spa, spa->spa_mos, child_dir_zapobj,
3234 	    &child_dir_zap) != 0) {
3235 		printf("ZFS: can't find child zap %ju\n", (uintmax_t)dir_obj);
3236 		return (EIO);
3237 	}
3238 
3239 	return (zap_list(spa, &child_dir_zap) != 0);
3240 }
3241 
3242 int
3243 zfs_callback_dataset(const spa_t *spa, uint64_t objnum,
3244     int (*callback)(const char *, uint64_t))
3245 {
3246 	uint64_t dir_obj, child_dir_zapobj;
3247 	dnode_phys_t child_dir_zap, dir, dataset;
3248 	dsl_dataset_phys_t *ds;
3249 	dsl_dir_phys_t *dd;
3250 	zap_phys_t *zap;
3251 	size_t size;
3252 	int err;
3253 
3254 	err = objset_get_dnode(spa, spa->spa_mos, objnum, &dataset);
3255 	if (err != 0) {
3256 		printf("ZFS: can't find dataset %ju\n", (uintmax_t)objnum);
3257 		return (err);
3258 	}
3259 	ds = (dsl_dataset_phys_t *)&dataset.dn_bonus;
3260 	dir_obj = ds->ds_dir_obj;
3261 
3262 	err = objset_get_dnode(spa, spa->spa_mos, dir_obj, &dir);
3263 	if (err != 0) {
3264 		printf("ZFS: can't find dirobj %ju\n", (uintmax_t)dir_obj);
3265 		return (err);
3266 	}
3267 	dd = (dsl_dir_phys_t *)&dir.dn_bonus;
3268 
3269 	child_dir_zapobj = dd->dd_child_dir_zapobj;
3270 	err = objset_get_dnode(spa, spa->spa_mos, child_dir_zapobj,
3271 	    &child_dir_zap);
3272 	if (err != 0) {
3273 		printf("ZFS: can't find child zap %ju\n", (uintmax_t)dir_obj);
3274 		return (err);
3275 	}
3276 
3277 	size = child_dir_zap.dn_datablkszsec << SPA_MINBLOCKSHIFT;
3278 	zap = malloc(size);
3279 	if (zap != NULL) {
3280 		err = dnode_read(spa, &child_dir_zap, 0, zap, size);
3281 		if (err != 0)
3282 			goto done;
3283 
3284 		if (zap->zap_block_type == ZBT_MICRO)
3285 			err = mzap_list((const mzap_phys_t *)zap, size,
3286 			    callback);
3287 		else
3288 			err = fzap_list(spa, &child_dir_zap, zap, callback);
3289 	} else {
3290 		err = ENOMEM;
3291 	}
3292 done:
3293 	free(zap);
3294 	return (err);
3295 }
3296 #endif
3297 
3298 /*
3299  * Find the object set given the object number of its dataset object
3300  * and return its details in *objset
3301  */
3302 static int
3303 zfs_mount_dataset(const spa_t *spa, uint64_t objnum, objset_phys_t *objset)
3304 {
3305 	dnode_phys_t dataset;
3306 	dsl_dataset_phys_t *ds;
3307 
3308 	if (objset_get_dnode(spa, spa->spa_mos, objnum, &dataset)) {
3309 		printf("ZFS: can't find dataset %ju\n", (uintmax_t)objnum);
3310 		return (EIO);
3311 	}
3312 
3313 	ds = (dsl_dataset_phys_t *)&dataset.dn_bonus;
3314 	if (zio_read(spa, &ds->ds_bp, objset)) {
3315 		printf("ZFS: can't read object set for dataset %ju\n",
3316 		    (uintmax_t)objnum);
3317 		return (EIO);
3318 	}
3319 
3320 	return (0);
3321 }
3322 
3323 /*
3324  * Find the object set pointed to by the BOOTFS property or the root
3325  * dataset if there is none and return its details in *objset
3326  */
3327 static int
3328 zfs_get_root(const spa_t *spa, uint64_t *objid)
3329 {
3330 	dnode_phys_t dir, propdir;
3331 	uint64_t props, bootfs, root;
3332 
3333 	*objid = 0;
3334 
3335 	/*
3336 	 * Start with the MOS directory object.
3337 	 */
3338 	if (objset_get_dnode(spa, spa->spa_mos,
3339 	    DMU_POOL_DIRECTORY_OBJECT, &dir)) {
3340 		printf("ZFS: can't read MOS object directory\n");
3341 		return (EIO);
3342 	}
3343 
3344 	/*
3345 	 * Lookup the pool_props and see if we can find a bootfs.
3346 	 */
3347 	if (zap_lookup(spa, &dir, DMU_POOL_PROPS,
3348 	    sizeof(props), 1, &props) == 0 &&
3349 	    objset_get_dnode(spa, spa->spa_mos, props, &propdir) == 0 &&
3350 	    zap_lookup(spa, &propdir, "bootfs",
3351 	    sizeof(bootfs), 1, &bootfs) == 0 && bootfs != 0) {
3352 		*objid = bootfs;
3353 		return (0);
3354 	}
3355 	/*
3356 	 * Lookup the root dataset directory
3357 	 */
3358 	if (zap_lookup(spa, &dir, DMU_POOL_ROOT_DATASET,
3359 	    sizeof(root), 1, &root) ||
3360 	    objset_get_dnode(spa, spa->spa_mos, root, &dir)) {
3361 		printf("ZFS: can't find root dsl_dir\n");
3362 		return (EIO);
3363 	}
3364 
3365 	/*
3366 	 * Use the information from the dataset directory's bonus buffer
3367 	 * to find the dataset object and from that the object set itself.
3368 	 */
3369 	dsl_dir_phys_t *dd = (dsl_dir_phys_t *)&dir.dn_bonus;
3370 	*objid = dd->dd_head_dataset_obj;
3371 	return (0);
3372 }
3373 
3374 static int
3375 zfs_mount_impl(const spa_t *spa, uint64_t rootobj, struct zfsmount *mount)
3376 {
3377 
3378 	mount->spa = spa;
3379 
3380 	/*
3381 	 * Find the root object set if not explicitly provided
3382 	 */
3383 	if (rootobj == 0 && zfs_get_root(spa, &rootobj)) {
3384 		printf("ZFS: can't find root filesystem\n");
3385 		return (EIO);
3386 	}
3387 
3388 	if (zfs_mount_dataset(spa, rootobj, &mount->objset)) {
3389 		printf("ZFS: can't open root filesystem\n");
3390 		return (EIO);
3391 	}
3392 
3393 	mount->rootobj = rootobj;
3394 
3395 	return (0);
3396 }
3397 
3398 /*
3399  * callback function for feature name checks.
3400  */
3401 static int
3402 check_feature(const char *name, uint64_t value)
3403 {
3404 	int i;
3405 
3406 	if (value == 0)
3407 		return (0);
3408 	if (name[0] == '\0')
3409 		return (0);
3410 
3411 	for (i = 0; features_for_read[i] != NULL; i++) {
3412 		if (strcmp(name, features_for_read[i]) == 0)
3413 			return (0);
3414 	}
3415 	printf("ZFS: unsupported feature: %s\n", name);
3416 	return (EIO);
3417 }
3418 
3419 /*
3420  * Checks whether the MOS features that are active are supported.
3421  */
3422 static int
3423 check_mos_features(const spa_t *spa)
3424 {
3425 	dnode_phys_t dir;
3426 	zap_phys_t *zap;
3427 	uint64_t objnum;
3428 	size_t size;
3429 	int rc;
3430 
3431 	if ((rc = objset_get_dnode(spa, spa->spa_mos, DMU_OT_OBJECT_DIRECTORY,
3432 	    &dir)) != 0)
3433 		return (rc);
3434 	if ((rc = zap_lookup(spa, &dir, DMU_POOL_FEATURES_FOR_READ,
3435 	    sizeof (objnum), 1, &objnum)) != 0) {
3436 		/*
3437 		 * It is older pool without features. As we have already
3438 		 * tested the label, just return without raising the error.
3439 		 */
3440 		return (0);
3441 	}
3442 
3443 	if ((rc = objset_get_dnode(spa, spa->spa_mos, objnum, &dir)) != 0)
3444 		return (rc);
3445 
3446 	if (dir.dn_type != DMU_OTN_ZAP_METADATA)
3447 		return (EIO);
3448 
3449 	size = dir.dn_datablkszsec << SPA_MINBLOCKSHIFT;
3450 	zap = malloc(size);
3451 	if (zap == NULL)
3452 		return (ENOMEM);
3453 
3454 	if (dnode_read(spa, &dir, 0, zap, size)) {
3455 		free(zap);
3456 		return (EIO);
3457 	}
3458 
3459 	if (zap->zap_block_type == ZBT_MICRO)
3460 		rc = mzap_list((const mzap_phys_t *)zap, size, check_feature);
3461 	else
3462 		rc = fzap_list(spa, &dir, zap, check_feature);
3463 
3464 	free(zap);
3465 	return (rc);
3466 }
3467 
3468 static int
3469 load_nvlist(spa_t *spa, uint64_t obj, nvlist_t **value)
3470 {
3471 	dnode_phys_t dir;
3472 	size_t size;
3473 	int rc;
3474 	char *nv;
3475 
3476 	*value = NULL;
3477 	if ((rc = objset_get_dnode(spa, spa->spa_mos, obj, &dir)) != 0)
3478 		return (rc);
3479 	if (dir.dn_type != DMU_OT_PACKED_NVLIST &&
3480 	    dir.dn_bonustype != DMU_OT_PACKED_NVLIST_SIZE) {
3481 		return (EIO);
3482 	}
3483 
3484 	if (dir.dn_bonuslen != sizeof (uint64_t))
3485 		return (EIO);
3486 
3487 	size = *(uint64_t *)DN_BONUS(&dir);
3488 	nv = malloc(size);
3489 	if (nv == NULL)
3490 		return (ENOMEM);
3491 
3492 	rc = dnode_read(spa, &dir, 0, nv, size);
3493 	if (rc != 0) {
3494 		free(nv);
3495 		nv = NULL;
3496 		return (rc);
3497 	}
3498 	*value = nvlist_import(nv, size);
3499 	free(nv);
3500 	return (rc);
3501 }
3502 
3503 static int
3504 zfs_spa_init(spa_t *spa)
3505 {
3506 	struct uberblock checkpoint;
3507 	dnode_phys_t dir;
3508 	uint64_t config_object;
3509 	nvlist_t *nvlist;
3510 	int rc;
3511 
3512 	if (zio_read(spa, &spa->spa_uberblock->ub_rootbp, spa->spa_mos)) {
3513 		printf("ZFS: can't read MOS of pool %s\n", spa->spa_name);
3514 		return (EIO);
3515 	}
3516 	if (spa->spa_mos->os_type != DMU_OST_META) {
3517 		printf("ZFS: corrupted MOS of pool %s\n", spa->spa_name);
3518 		return (EIO);
3519 	}
3520 
3521 	if (objset_get_dnode(spa, &spa->spa_mos_master,
3522 	    DMU_POOL_DIRECTORY_OBJECT, &dir)) {
3523 		printf("ZFS: failed to read pool %s directory object\n",
3524 		    spa->spa_name);
3525 		return (EIO);
3526 	}
3527 	/* this is allowed to fail, older pools do not have salt */
3528 	rc = zap_lookup(spa, &dir, DMU_POOL_CHECKSUM_SALT, 1,
3529 	    sizeof (spa->spa_cksum_salt.zcs_bytes),
3530 	    spa->spa_cksum_salt.zcs_bytes);
3531 
3532 	rc = check_mos_features(spa);
3533 	if (rc != 0) {
3534 		printf("ZFS: pool %s is not supported\n", spa->spa_name);
3535 		return (rc);
3536 	}
3537 
3538 	rc = zap_lookup(spa, &dir, DMU_POOL_CONFIG,
3539 	    sizeof (config_object), 1, &config_object);
3540 	if (rc != 0) {
3541 		printf("ZFS: can not read MOS %s\n", DMU_POOL_CONFIG);
3542 		return (EIO);
3543 	}
3544 	rc = load_nvlist(spa, config_object, &nvlist);
3545 	if (rc != 0)
3546 		return (rc);
3547 
3548 	rc = zap_lookup(spa, &dir, DMU_POOL_ZPOOL_CHECKPOINT,
3549 	    sizeof(uint64_t), sizeof(checkpoint) / sizeof(uint64_t),
3550 	    &checkpoint);
3551 	if (rc == 0 && checkpoint.ub_checkpoint_txg != 0) {
3552 		memcpy(&spa->spa_uberblock_checkpoint, &checkpoint,
3553 		    sizeof(checkpoint));
3554 		if (zio_read(spa, &spa->spa_uberblock_checkpoint.ub_rootbp,
3555 		    &spa->spa_mos_checkpoint)) {
3556 			printf("ZFS: can not read checkpoint data.\n");
3557 			return (EIO);
3558 		}
3559 	}
3560 
3561 	/*
3562 	 * Update vdevs from MOS config. Note, we do skip encoding bytes
3563 	 * here. See also vdev_label_read_config().
3564 	 */
3565 	rc = vdev_init_from_nvlist(spa, nvlist);
3566 	nvlist_destroy(nvlist);
3567 	return (rc);
3568 }
3569 
3570 static int
3571 zfs_dnode_stat(const spa_t *spa, dnode_phys_t *dn, struct stat *sb)
3572 {
3573 
3574 	if (dn->dn_bonustype != DMU_OT_SA) {
3575 		znode_phys_t *zp = (znode_phys_t *)dn->dn_bonus;
3576 
3577 		sb->st_mode = zp->zp_mode;
3578 		sb->st_uid = zp->zp_uid;
3579 		sb->st_gid = zp->zp_gid;
3580 		sb->st_size = zp->zp_size;
3581 	} else {
3582 		sa_hdr_phys_t *sahdrp;
3583 		int hdrsize;
3584 		size_t size = 0;
3585 		void *buf = NULL;
3586 
3587 		if (dn->dn_bonuslen != 0)
3588 			sahdrp = (sa_hdr_phys_t *)DN_BONUS(dn);
3589 		else {
3590 			if ((dn->dn_flags & DNODE_FLAG_SPILL_BLKPTR) != 0) {
3591 				blkptr_t *bp = DN_SPILL_BLKPTR(dn);
3592 				int error;
3593 
3594 				size = BP_GET_LSIZE(bp);
3595 				buf = malloc(size);
3596 				if (buf == NULL)
3597 					error = ENOMEM;
3598 				else
3599 					error = zio_read(spa, bp, buf);
3600 
3601 				if (error != 0) {
3602 					free(buf);
3603 					return (error);
3604 				}
3605 				sahdrp = buf;
3606 			} else {
3607 				return (EIO);
3608 			}
3609 		}
3610 		hdrsize = SA_HDR_SIZE(sahdrp);
3611 		sb->st_mode = *(uint64_t *)((char *)sahdrp + hdrsize +
3612 		    SA_MODE_OFFSET);
3613 		sb->st_uid = *(uint64_t *)((char *)sahdrp + hdrsize +
3614 		    SA_UID_OFFSET);
3615 		sb->st_gid = *(uint64_t *)((char *)sahdrp + hdrsize +
3616 		    SA_GID_OFFSET);
3617 		sb->st_size = *(uint64_t *)((char *)sahdrp + hdrsize +
3618 		    SA_SIZE_OFFSET);
3619 		free(buf);
3620 	}
3621 
3622 	return (0);
3623 }
3624 
3625 static int
3626 zfs_dnode_readlink(const spa_t *spa, dnode_phys_t *dn, char *path, size_t psize)
3627 {
3628 	int rc = 0;
3629 
3630 	if (dn->dn_bonustype == DMU_OT_SA) {
3631 		sa_hdr_phys_t *sahdrp = NULL;
3632 		size_t size = 0;
3633 		void *buf = NULL;
3634 		int hdrsize;
3635 		char *p;
3636 
3637 		if (dn->dn_bonuslen != 0) {
3638 			sahdrp = (sa_hdr_phys_t *)DN_BONUS(dn);
3639 		} else {
3640 			blkptr_t *bp;
3641 
3642 			if ((dn->dn_flags & DNODE_FLAG_SPILL_BLKPTR) == 0)
3643 				return (EIO);
3644 			bp = DN_SPILL_BLKPTR(dn);
3645 
3646 			size = BP_GET_LSIZE(bp);
3647 			buf = malloc(size);
3648 			if (buf == NULL)
3649 				rc = ENOMEM;
3650 			else
3651 				rc = zio_read(spa, bp, buf);
3652 			if (rc != 0) {
3653 				free(buf);
3654 				return (rc);
3655 			}
3656 			sahdrp = buf;
3657 		}
3658 		hdrsize = SA_HDR_SIZE(sahdrp);
3659 		p = (char *)((uintptr_t)sahdrp + hdrsize + SA_SYMLINK_OFFSET);
3660 		memcpy(path, p, psize);
3661 		free(buf);
3662 		return (0);
3663 	}
3664 	/*
3665 	 * Second test is purely to silence bogus compiler
3666 	 * warning about accessing past the end of dn_bonus.
3667 	 */
3668 	if (psize + sizeof(znode_phys_t) <= dn->dn_bonuslen &&
3669 	    sizeof(znode_phys_t) <= sizeof(dn->dn_bonus)) {
3670 		memcpy(path, &dn->dn_bonus[sizeof(znode_phys_t)], psize);
3671 	} else {
3672 		rc = dnode_read(spa, dn, 0, path, psize);
3673 	}
3674 	return (rc);
3675 }
3676 
3677 struct obj_list {
3678 	uint64_t		objnum;
3679 	STAILQ_ENTRY(obj_list)	entry;
3680 };
3681 
3682 /*
3683  * Lookup a file and return its dnode.
3684  */
3685 static int
3686 zfs_lookup(const struct zfsmount *mount, const char *upath, dnode_phys_t *dnode)
3687 {
3688 	int rc;
3689 	uint64_t objnum;
3690 	const spa_t *spa;
3691 	dnode_phys_t dn;
3692 	const char *p, *q;
3693 	char element[256];
3694 	char path[1024];
3695 	int symlinks_followed = 0;
3696 	struct stat sb;
3697 	struct obj_list *entry, *tentry;
3698 	STAILQ_HEAD(, obj_list) on_cache = STAILQ_HEAD_INITIALIZER(on_cache);
3699 
3700 	spa = mount->spa;
3701 	if (mount->objset.os_type != DMU_OST_ZFS) {
3702 		printf("ZFS: unexpected object set type %ju\n",
3703 		    (uintmax_t)mount->objset.os_type);
3704 		return (EIO);
3705 	}
3706 
3707 	if ((entry = malloc(sizeof(struct obj_list))) == NULL)
3708 		return (ENOMEM);
3709 
3710 	/*
3711 	 * Get the root directory dnode.
3712 	 */
3713 	rc = objset_get_dnode(spa, &mount->objset, MASTER_NODE_OBJ, &dn);
3714 	if (rc) {
3715 		free(entry);
3716 		return (rc);
3717 	}
3718 
3719 	rc = zap_lookup(spa, &dn, ZFS_ROOT_OBJ, sizeof(objnum), 1, &objnum);
3720 	if (rc) {
3721 		free(entry);
3722 		return (rc);
3723 	}
3724 	entry->objnum = objnum;
3725 	STAILQ_INSERT_HEAD(&on_cache, entry, entry);
3726 
3727 	rc = objset_get_dnode(spa, &mount->objset, objnum, &dn);
3728 	if (rc != 0)
3729 		goto done;
3730 
3731 	p = upath;
3732 	while (p && *p) {
3733 		rc = objset_get_dnode(spa, &mount->objset, objnum, &dn);
3734 		if (rc != 0)
3735 			goto done;
3736 
3737 		while (*p == '/')
3738 			p++;
3739 		if (*p == '\0')
3740 			break;
3741 		q = p;
3742 		while (*q != '\0' && *q != '/')
3743 			q++;
3744 
3745 		/* skip dot */
3746 		if (p + 1 == q && p[0] == '.') {
3747 			p++;
3748 			continue;
3749 		}
3750 		/* double dot */
3751 		if (p + 2 == q && p[0] == '.' && p[1] == '.') {
3752 			p += 2;
3753 			if (STAILQ_FIRST(&on_cache) ==
3754 			    STAILQ_LAST(&on_cache, obj_list, entry)) {
3755 				rc = ENOENT;
3756 				goto done;
3757 			}
3758 			entry = STAILQ_FIRST(&on_cache);
3759 			STAILQ_REMOVE_HEAD(&on_cache, entry);
3760 			free(entry);
3761 			objnum = (STAILQ_FIRST(&on_cache))->objnum;
3762 			continue;
3763 		}
3764 		if (q - p + 1 > sizeof(element)) {
3765 			rc = ENAMETOOLONG;
3766 			goto done;
3767 		}
3768 		memcpy(element, p, q - p);
3769 		element[q - p] = 0;
3770 		p = q;
3771 
3772 		if ((rc = zfs_dnode_stat(spa, &dn, &sb)) != 0)
3773 			goto done;
3774 		if (!S_ISDIR(sb.st_mode)) {
3775 			rc = ENOTDIR;
3776 			goto done;
3777 		}
3778 
3779 		rc = zap_lookup(spa, &dn, element, sizeof (objnum), 1, &objnum);
3780 		if (rc)
3781 			goto done;
3782 		objnum = ZFS_DIRENT_OBJ(objnum);
3783 
3784 		if ((entry = malloc(sizeof(struct obj_list))) == NULL) {
3785 			rc = ENOMEM;
3786 			goto done;
3787 		}
3788 		entry->objnum = objnum;
3789 		STAILQ_INSERT_HEAD(&on_cache, entry, entry);
3790 		rc = objset_get_dnode(spa, &mount->objset, objnum, &dn);
3791 		if (rc)
3792 			goto done;
3793 
3794 		/*
3795 		 * Check for symlink.
3796 		 */
3797 		rc = zfs_dnode_stat(spa, &dn, &sb);
3798 		if (rc)
3799 			goto done;
3800 		if (S_ISLNK(sb.st_mode)) {
3801 			if (symlinks_followed > 10) {
3802 				rc = EMLINK;
3803 				goto done;
3804 			}
3805 			symlinks_followed++;
3806 
3807 			/*
3808 			 * Read the link value and copy the tail of our
3809 			 * current path onto the end.
3810 			 */
3811 			if (sb.st_size + strlen(p) + 1 > sizeof(path)) {
3812 				rc = ENAMETOOLONG;
3813 				goto done;
3814 			}
3815 			strcpy(&path[sb.st_size], p);
3816 
3817 			rc = zfs_dnode_readlink(spa, &dn, path, sb.st_size);
3818 			if (rc != 0)
3819 				goto done;
3820 
3821 			/*
3822 			 * Restart with the new path, starting either at
3823 			 * the root or at the parent depending whether or
3824 			 * not the link is relative.
3825 			 */
3826 			p = path;
3827 			if (*p == '/') {
3828 				while (STAILQ_FIRST(&on_cache) !=
3829 				    STAILQ_LAST(&on_cache, obj_list, entry)) {
3830 					entry = STAILQ_FIRST(&on_cache);
3831 					STAILQ_REMOVE_HEAD(&on_cache, entry);
3832 					free(entry);
3833 				}
3834 			} else {
3835 				entry = STAILQ_FIRST(&on_cache);
3836 				STAILQ_REMOVE_HEAD(&on_cache, entry);
3837 				free(entry);
3838 			}
3839 			objnum = (STAILQ_FIRST(&on_cache))->objnum;
3840 		}
3841 	}
3842 
3843 	*dnode = dn;
3844 done:
3845 	STAILQ_FOREACH_SAFE(entry, &on_cache, entry, tentry)
3846 		free(entry);
3847 	return (rc);
3848 }
3849 
3850 /*
3851  * Return either a cached copy of the bootenv, or read each of the vdev children
3852  * looking for the bootenv. Cache what's found and return the results. Returns 0
3853  * when benvp is filled in, and some errno when not.
3854  */
3855 static int
3856 zfs_get_bootenv_spa(spa_t *spa, nvlist_t **benvp)
3857 {
3858 	vdev_t *vd;
3859 	nvlist_t *benv = NULL;
3860 
3861 	if (spa->spa_bootenv == NULL) {
3862 		STAILQ_FOREACH(vd, &spa->spa_root_vdev->v_children,
3863 		    v_childlink) {
3864 			benv = vdev_read_bootenv(vd);
3865 
3866 			if (benv != NULL)
3867 				break;
3868 		}
3869 		spa->spa_bootenv = benv;
3870 	}
3871 	benv = spa->spa_bootenv;
3872 
3873 	if (benv == NULL)
3874 		return (ENOENT);
3875 
3876 	*benvp = benv;
3877 	return (0);
3878 }
3879 
3880 /*
3881  * Store nvlist to pool label bootenv area. Also updates cached pointer in spa.
3882  */
3883 static int
3884 zfs_set_bootenv_spa(spa_t *spa, nvlist_t *benv)
3885 {
3886 	vdev_t *vd;
3887 
3888 	STAILQ_FOREACH(vd, &spa->spa_root_vdev->v_children, v_childlink) {
3889 		vdev_write_bootenv(vd, benv);
3890 	}
3891 
3892 	spa->spa_bootenv = benv;
3893 	return (0);
3894 }
3895 
3896 /*
3897  * Get bootonce value by key. The bootonce <key, value> pair is removed from the
3898  * bootenv nvlist and the remaining nvlist is committed back to disk. This process
3899  * the bootonce flag since we've reached the point in the boot that we've 'used'
3900  * the BE. For chained boot scenarios, we may reach this point multiple times (but
3901  * only remove it and return 0 the first time).
3902  */
3903 static int
3904 zfs_get_bootonce_spa(spa_t *spa, const char *key, char *buf, size_t size)
3905 {
3906 	nvlist_t *benv;
3907 	char *result = NULL;
3908 	int result_size, rv;
3909 
3910 	if ((rv = zfs_get_bootenv_spa(spa, &benv)) != 0)
3911 		return (rv);
3912 
3913 	if ((rv = nvlist_find(benv, key, DATA_TYPE_STRING, NULL,
3914 	    &result, &result_size)) == 0) {
3915 		if (result_size == 0) {
3916 			/* ignore empty string */
3917 			rv = ENOENT;
3918 		} else if (buf != NULL) {
3919 			size = MIN((size_t)result_size + 1, size);
3920 			strlcpy(buf, result, size);
3921 		}
3922 		(void)nvlist_remove(benv, key, DATA_TYPE_STRING);
3923 		(void)zfs_set_bootenv_spa(spa, benv);
3924 	}
3925 
3926 	return (rv);
3927 }
3928